Elastic nonwoven fabric and process for producing the same

Abstract

The present application relates to a kind of elastic nonwoven fabric and its preparation process.Elastic nonwoven fabric includes upper substrate, lower substrate and elastic layer, elastic layer is between upper substrate and lower substrate, and upper substrate and lower substrate are respectively formed by at least two layers of nonwoven fabric, the lowermost layer of nonwoven fabric of upper substrate has multiple first hot melt grooves parallel and along the length direction of nonwoven fabric, each layer of nonwoven fabric of upper substrate is connected by hot melt at first hot melt groove, the uppermost layer of nonwoven fabric of lower substrate has multiple second hot melt grooves parallel and along the length direction of nonwoven fabric, and each layer of nonwoven fabric of lower substrate is connected by hot melt at second hot melt groove, and elastic layer includes multiple spandex filaments, each first hot melt groove, spandex filament and second hot melt groove are respectively one-to-one corresponding arrangement and are bonded by hot melt adhesive in first hot melt groove and second hot melt groove, and the produced elastic nonwoven fabric is not only good in air permeability, and the combination between each layer of nonwoven fabric is very close, avoids delamination.

Description

Technical Field

[0001] This invention relates to an elastic nonwoven fabric and its preparation process. Background Technology

[0002] Elastic nonwoven fabrics mainly consist of an upper substrate, an elastic layer, and a lower substrate. In some scenarios, the thickness of the upper and lower substrates made of nonwoven fabrics needs to be changed. For example, multiple layers or multiple nonwoven fabrics need to be combined to increase the thickness or improve the physical properties. Traditional hydroentangling methods result in poor hydroentangling effect due to the nonwoven fabric being too thick, and it is easy for the layers to separate.

[0003] The existing elastic nonwoven fabric is prepared by spraying hot melt adhesive onto the upper and lower substrates, then adhering the spandex filaments of the elastic layer to the sprayed adhesive layer, and then bonding them together to form an integral structure. This method affects the air permeability of the elastic nonwoven fabric because the sprayed adhesive layer covers a large area, and the adhesive mist easily adheres to the production equipment, making it difficult to clean. Summary of the Invention

[0004] The purpose of this invention is to provide an elastic nonwoven fabric and its preparation process. The produced elastic nonwoven fabric not only has good air permeability, but also has very tight bonding between the layers of nonwoven fabric, avoiding separation and delamination.

[0005] The technical solution of the elastic nonwoven fabric preparation process of the present invention is as follows: The elastic nonwoven fabric preparation process includes the following steps:

[0006] S1. Processing the upper base: overlap at least two layers of nonwoven fabric constituting the upper base, stretch them, and wrap them around the first heating roller. Multiple first annular protrusions are spaced apart along the axial direction on the first heating roller. Multiple parallel first hot melt grooves extending along the length of the nonwoven fabric are hot melted on the bottom layer of the upper base using the first annular protrusions. The layers of nonwoven fabric on the upper base are hot melted together through the first hot melt grooves. The hot melt groove is a groove formed under the dual action of heating and pressurization. The groove is also the hot melt bonding point of each layer of nonwoven fabric.

[0007] S2. Process the lower base. Overlap at least two layers of nonwoven fabric constituting the lower base and stretch them and wrap them around the second heating roller. Multiple second annular protrusions are spaced apart on the second heating roller along the axial direction. Multiple parallel second hot melt grooves that extend along the length of the nonwoven fabric are hot melted on the uppermost layer of nonwoven fabric of the lower base using the second annular protrusions. The layers of nonwoven fabric of the lower base are hot melted together through the second hot melt grooves.

[0008] S3. Applying adhesive to the first and second hot melt tanks: The adhesive is applied to the first and second hot melt tanks respectively by the adhesive application mechanism. The adhesive application mechanism includes an adhesive application head that is arranged one-to-one with each of the first and second hot melt tanks. The adhesive application head ensures that the adhesive is only distributed in the hot melt tank, thereby ensuring that the area between the hot melt tanks still has good air permeability.

[0009] S4. Elastic layer combing: The elastic layer spandex filaments are combed by combing teeth to arrange the spandex filaments at equal intervals. The spacing between adjacent spandex filaments is the same as the spacing between adjacent first hot melt tanks and adjacent second hot melt tanks, which facilitates subsequent compounding on the production line.

[0010] S5. The upper substrate, elastic layer and lower substrate are composited. The upper substrate, elastic layer and lower substrate are stacked one on top of the other in sequence to ensure that each of the first hot melt groove, spandex filament and second hot melt groove corresponds one to one. Then, under tension, the upper substrate, spandex filament and lower substrate are hot-pressed together by passing around the heating traction wheel. The heating traction wheel also has the function of heating and pressurizing, but its heating temperature is lower than that of the heating roller. Its purpose is to ensure that some solidified glue can melt to improve the bonding performance, but its temperature is lower than the hot melt temperature of the nonwoven fabric.

[0011] Based on the above solution, a further improvement is made as follows: a heating resistance wire is provided in the first and / or second annular protrusions, so that only the corresponding first or second annular protrusion is heated. This ensures that heating is only applied to the hot melt groove.

[0012] Based on the above solution, further improvements are made as follows: the glue application mechanism includes a rectangular glue application cavity, and all glue application heads of the mechanism share the same cavity. This facilitates the unified heating and delivery of the hot melt adhesive.

[0013] Based on the above scheme, the following improvements are made: the cross-section of the first and / or second annular protrusions is arc-shaped or trapezoidal.

[0014] The technical solution of the elastic nonwoven fabric of the present invention is as follows: The elastic nonwoven fabric includes an upper substrate, a lower substrate, and an elastic layer. The elastic layer is located between the upper and lower substrates. The upper and lower substrates are each composed of at least two layers of nonwoven fabric. The bottommost layer of nonwoven fabric of the upper substrate has multiple parallel first hot melt grooves extending along the length of the nonwoven fabric. The layers of nonwoven fabric of the upper substrate are heat-fused together through the first hot melt grooves. The topmost layer of nonwoven fabric of the lower substrate has multiple parallel second hot melt grooves extending along the length of the nonwoven fabric. The layers of nonwoven fabric of the lower substrate are heat-fused together through the second hot melt grooves. The elastic layer includes multiple spandex filaments. Each first hot melt groove, spandex filament, and second hot melt groove is respectively arranged in a one-to-one correspondence and is bonded to each other by hot melt adhesive located in the first and second hot melt grooves.

[0015] Based on the above scheme, the following improvements are made: the cross-section of the first and / or second hot melt groove is arc-shaped or trapezoidal.

[0016] Based on the above scheme, the following improvements are made: the nonwoven fabrics of each layer of the upper substrate and / or lower substrate are composed of nonwoven fabrics of different materials.

[0017] Based on the above scheme, the following improvements are made: each layer of nonwoven fabric in the upper substrate and / or lower substrate is composed of nonwoven fabric of the same material.

[0018] Based on the above scheme, further improvements are made as follows: the basis weight range of single-layer nonwoven fabric is 12-60 g / m². 2 The fiber fineness of spandex yarn is 50D-540D, the spacing between two adjacent spandex yarns is 1-8mm, and the elongation ratio of spandex yarn is 1.1-3.5.

[0019] The beneficial effects of this invention are as follows: Compared with the prior art, when the upper and lower substrates of the elastic nonwoven fabric of this application need to increase thickness or require composite nonwoven fabrics made of multiple materials, the upper and lower substrates are joined by heat-melting multiple parallel vertical heat-melting grooves to achieve heat-melting connection of each layer of nonwoven fabric. Traditional hydroentangling methods cannot penetrate thicker nonwoven fabrics to achieve a good connection, and are prone to delamination. Simultaneously, the heat-melting grooves are used as adhesive reservoirs, ensuring that the adhesive is only distributed within the grooves, thus avoiding the adhesive completely covering the nonwoven fabric and affecting its breathability. This also saves on adhesive usage. Furthermore, the heat-melting grooves also serve as space to accommodate spandex fibers, preventing protrusions at the spandex fibers from affecting wearing comfort. Compared with the prior art, the elastic nonwoven fabric of this application has good breathability, and the bonding between each layer of nonwoven fabric is very tight. Especially after hot pressing with a heating traction wheel after lamination, the slightly cured adhesive is further melted, and the tightness of the bonding is further improved under pressure. It also has the advantage of avoiding delamination. The corresponding preparation process is also very fast and efficient, suitable for assembly line production, improving production efficiency. Attached Figure Description

[0020] Figure 1 This is a partial cross-sectional view of a specific embodiment of the elastic nonwoven fabric of the present invention.

[0021] Figure 2 A schematic diagram of the production line principle for the preparation process of elastic nonwoven fabric;

[0022] Figure 3 This is the front view of the first heating roller (drawn in a detached manner).

[0023] Figure 4 This is a schematic diagram of the joint between the adhesive application mechanism and the lower substrate.

[0024] In the figure: 1-upper substrate, 11-upper nonwoven fabric of the upper substrate, 12-lower nonwoven fabric of the upper substrate, 121-first hot melt groove, 2-lower substrate, 21-upper nonwoven fabric of the lower substrate, 211-second hot melt groove, 22-lower nonwoven fabric of the lower substrate, 3-spandex filament, 4-carding teeth, 5-guide wheel, 6-first heating roller, 61-first annular convex strip, 7-adhesive coating mechanism, 71-adhesive coating head, 72-adhesive coating cavity, 8-second heating roller, 9-heating traction wheel. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0028] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0029] Specific embodiments of the elastic nonwoven fabric of the present invention: such as Figure 1As shown, the elastic nonwoven fabric includes an upper substrate 1, a lower substrate 2, and an elastic layer. The elastic layer is located between the upper and lower substrates. The upper and lower substrates are each composed of at least two layers of nonwoven fabric. In this embodiment, there are two layers made of two different materials. The bottom layer of the upper substrate 1 has multiple parallel first hot-melt grooves 121 extending along the length of the nonwoven fabric. The layers of nonwoven fabric in the upper substrate 1 are heat-fused together through the first hot-melt grooves 121. The top layer of the lower substrate 2 has multiple parallel second hot-melt grooves 211 extending along the length of the nonwoven fabric. The layers of nonwoven fabric in the lower substrate 2 are heat-fused together through the second hot-melt grooves 211. The elastic layer includes multiple spandex filaments 3. Each first hot-melt groove 121, spandex filament 3, and second hot-melt groove 211 is respectively arranged in a one-to-one correspondence and is bonded to each other by hot-melt adhesive located in the first hot-melt grooves 121 and the second hot-melt grooves 211. The cross-sections of the first hot-melt grooves 121 and the second hot-melt grooves 211 are trapezoidal.

[0030] Specifically, the elastic nonwoven fabric includes an upper substrate, a lower substrate, and an elastic layer sandwiched between the two. The three are bonded together to form an elastic composite layer. The basis weight of a single layer of nonwoven fabric ranges from 12 to 60 g / m². 2 The elastic composite layer has a stretch ratio of 2-3 times. The elastic layer is composed of multiple spandex filaments arranged in the same direction and at equal intervals. The spandex filaments have a fiber fineness of 50D-540D, a spacing of 1-8mm between adjacent filaments, and a stretch ratio of 1.1-3.5. For example, one embodiment of the spandex filaments has a fiber fineness of 140D, a stretch ratio of 2.2, and a spacing of 2mm between adjacent filaments.

[0031] In this application, the upper and lower substrates of the elastic nonwoven fabric require increased thickness or the composite of nonwoven fabrics made of multiple materials. This is achieved by using multiple parallel vertical hot-melt grooves to achieve hot-melt bonding of the nonwoven fabric layers. Traditional hydroentangling methods cannot penetrate thicker nonwoven fabrics to achieve a good bond, easily leading to delamination. Simultaneously, the hot-melt grooves serve as adhesive reservoirs, ensuring the adhesive is only distributed within them. This prevents the adhesive from completely covering the nonwoven fabric, which would affect its breathability, and also saves on adhesive usage. Furthermore, the hot-melt grooves also serve as space to accommodate spandex filaments 3, preventing protrusions at these filaments from affecting wearing comfort. Compared to existing technologies, the elastic nonwoven fabric of this application has excellent breathability, and the bonding between the layers is very tight. Especially after hot pressing with the heated traction wheel 9 after lamination, the slightly cured adhesive is further melted, and the tightness of the bonding is further improved under pressure. It also has the advantage of preventing delamination. The corresponding manufacturing process is also very fast and efficient, suitable for assembly line production, improving production efficiency.

[0032] Specific embodiments of the elastic nonwoven fabric preparation process of the present invention: as follows Figure 2-4 As shown, the process for preparing elastic nonwoven fabric includes the following steps:

[0033] In the upper substrate 1, at least two layers of nonwoven fabric constituting the upper substrate 1 are overlapped, stretched and wrapped around the first heating roller 6. Multiple first annular protrusions 61 are spaced apart along the axial direction on the first heating roller 6. Multiple parallel first hot melt grooves 121 extending along the length of the nonwoven fabric are hot melted on the bottom layer of the upper substrate 1 using the first annular protrusions 61. The layers of nonwoven fabric in the upper substrate 1 are hot melted together through the first hot melt grooves 121. The hot melt groove is a groove formed under the dual action of heating and pressurization. The groove is also the hot melt bonding point of each layer of nonwoven fabric.

[0034] Processing the lower base 2 involves overlapping and stretching at least two layers of nonwoven fabric constituting the lower base 2, and then passing them around the second heating roller 8. The second heating roller 8 has multiple second annular protrusions spaced along the axial direction. The second annular protrusions are used to heat-melt multiple parallel second hot melt grooves 211 on the uppermost layer of nonwoven fabric of the lower base 2. The layers of nonwoven fabric of the lower base 2 are heat-melted together through the second hot melt grooves 211.

[0035] The first hot melt tank 121 and the second hot melt tank 211 are coated with adhesive. The adhesive coating mechanism 7 is used to coat the first hot melt tank 121 and the second hot melt tank 211 respectively. The adhesive coating mechanism 7 includes an adhesive coating head 71 that is arranged one-to-one with each of the first hot melt tank 121 and each of the second hot melt tank 211. The adhesive coating head 71 ensures that the adhesive is only distributed in the hot melt tank, thereby ensuring that the area between the hot melt tanks still has good air permeability.

[0036] The elastic layer is combed by combing teeth 4 to comb each spandex filament 3 of the elastic layer, so that each spandex filament 3 is arranged at equal intervals, and the spacing between each adjacent spandex filament 3 is the same as the spacing between each adjacent first hot melt groove 121 and each adjacent second hot melt groove 211, which facilitates subsequent compounding on the production line.

[0037] The upper substrate 1, elastic layer and lower substrate 2 are composited. The upper substrate 1, elastic layer and lower substrate 2 are stacked one on top of the other in sequence to ensure that each of the first hot melt groove 121, spandex filament 3 and second hot melt groove 211 corresponds one to one. Then, under tension, the upper substrate 1, spandex filament 3 and lower substrate 2 are hot-pressed together by passing around the heating traction wheel 9. The heating traction wheel 9 also has the function of heating and pressurizing, but its heating temperature is lower than that of the heating roller. Its purpose is to ensure that some solidified glue can melt to improve the bonding performance, but its temperature is lower than the hot melt temperature of the nonwoven fabric.

[0038] In this embodiment, heating resistance wires are provided in the first annular protrusion 61 and the second annular protrusion, so that only the corresponding first annular protrusion 61 or second annular protrusion is heated. This ensures that only the hot melt groove is heated. The glue application mechanism 7 includes a rectangular glue application cavity 72, and each glue application head 71 of the glue application mechanism 7 shares the same glue application cavity 72. This facilitates the unified heating and delivery of hot melt adhesive. The cross-sections of the first annular protrusion 61 and the second annular protrusion are arc-shaped or trapezoidal.

[0039] Specifically, spandex filaments are unwound from the spandex filament unwinding mechanism. Several unwound spandex filaments pass through the spandex filament traction frame, which arranges adjacent spandex filaments at a fixed interval and conveys them backward. Nonwoven fabric is unwound from its corresponding unwinding frame, and the upper and lower substrates are unwound and conveyed backward under the traction of their respective downstream traction shafts. A slitting mechanism cuts the edge material of the elastic nonwoven fabric after it has passed through the heated traction wheel. The cut elastic nonwoven fabric continues to be conveyed backward, and the cut edge material is collected in a waste bin. The slitting mechanism includes two symmetrically arranged cutters, the distance between which can be adjusted according to actual production needs. Edge material is removed from both sides of the elastic nonwoven fabric after passing through the two cutters. A cooling traction assembly cools the elastic nonwoven fabric, allowing the adhesive inside the elastic nonwoven fabric to cool and set rapidly, and then continues to convey the elastic nonwoven fabric backward. The winding mechanism winds up the elastic nonwoven fabric output from the tension adjusting shaft to form an elastic nonwoven fabric roll. The formed elastic nonwoven fabric roll is left to rest naturally for 24-48 hours, and then the rested elastic nonwoven fabric roll is rewound to release the internal stress accumulated during the production process, eliminate uneven winding tension, and stabilize the performance of the elastic nonwoven fabric, thereby improving the rewinding quality and yield.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. The process for preparing elastic nonwoven fabric includes the following steps: S1. Process the upper base. Overlap at least two layers of nonwoven fabric constituting the upper base and stretch them and wrap them around the first heating roller. Multiple first annular protrusions are spaced apart along the axial direction on the first heating roller. Multiple parallel first hot melt grooves extending along the length of the nonwoven fabric are hot melted on the bottom layer of the upper base using the first annular protrusions. The layers of nonwoven fabric of the upper base are hot melted together through the first hot melt grooves. S2. Process the lower base. Overlap at least two layers of nonwoven fabric constituting the lower base and stretch them and wrap them around the second heating roller. Multiple second annular protrusions are spaced apart on the second heating roller along the axial direction. Multiple parallel second hot melt grooves that extend along the length of the nonwoven fabric are hot melted on the uppermost layer of nonwoven fabric of the lower base using the second annular protrusions. The layers of nonwoven fabric of the lower base are hot melted together through the second hot melt grooves. S3. Applying adhesive to the first and second hot melt tanks: Adhesive is applied to the first and second hot melt tanks respectively by an adhesive application mechanism. The adhesive application mechanism includes an adhesive application head that corresponds to each of the first and second hot melt tanks. S4. Elastic layer combing: The elastic layer spandex filaments are combed by combing teeth so that the spandex filaments are arranged at equal intervals, and the spacing between adjacent spandex filaments is the same as the spacing between adjacent first hot melt grooves and adjacent second hot melt grooves. S5. The upper substrate, elastic layer and lower substrate are composited. The upper substrate, elastic layer and lower substrate are stacked one on top of the other in sequence to ensure that each of the first hot melt groove, spandex filament and second hot melt groove corresponds one to one. Then, under tension, the upper substrate, spandex filament and lower substrate are hot-pressed together by passing around the heating traction wheel.

2. The process for preparing elastic nonwoven fabric according to claim 1, characterized in that, Heating resistance wires are provided in the first and / or second annular protrusions, so that only the corresponding first or second annular protrusion is heated.

3. The process for preparing elastic nonwoven fabric according to claim 1, characterized in that, The glue application mechanism includes a rectangular glue application cavity, and all glue application heads of the glue application mechanism share the same glue application cavity.

4. The process for preparing elastic nonwoven fabric according to claim 1, characterized in that, The cross-section of the first and / or second annular protrusion is arc-shaped or trapezoidal.

5. An elastic nonwoven fabric prepared by the elastic nonwoven fabric preparation process according to any one of claims 1-4, characterized in that, The device includes an upper substrate, a lower substrate, and an elastic layer. The elastic layer is located between the upper and lower substrates. The upper and lower substrates are each composed of at least two layers of nonwoven fabric. The bottom layer of nonwoven fabric on the upper substrate has multiple parallel first hot melt grooves extending along the length of the nonwoven fabric. The layers of nonwoven fabric on the upper substrate are heat-fused together through the first hot melt grooves. The top layer of nonwoven fabric on the lower substrate has multiple parallel second hot melt grooves extending along the length of the nonwoven fabric. The layers of nonwoven fabric on the lower substrate are heat-fused together through the second hot melt grooves. The elastic layer includes multiple spandex filaments. Each first hot melt groove, spandex filament, and second hot melt groove is respectively arranged in a one-to-one correspondence and is bonded to each other by hot melt adhesive located in the first and second hot melt grooves.

6. The elastic nonwoven fabric according to claim 5, characterized in that, The cross-section of the first and / or second hot melt groove is arc-shaped or trapezoidal.

7. The elastic nonwoven fabric according to claim 5, characterized in that, The upper and / or lower substrates are composed of nonwoven fabrics of different materials.

8. The elastic nonwoven fabric according to claim 5, characterized in that, Each layer of nonwoven fabric in the upper and / or lower substrate is made of the same material.

9. The elastic nonwoven fabric according to claim 5, characterized in that, The basis weight range of single-layer nonwoven fabric is 12-60 g / m². 2 The fiber fineness of spandex yarn is 50D-540D, the spacing between two adjacent spandex yarns is 1-8mm, and the elongation ratio of spandex yarn is 1.1-3.5.

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