Lightweight non-woven fabric and production method thereof

Abstract

The invention discloses a light-weight non-woven fabric and a production method thereof, belongs to the technical field of non-woven fabrics, and solves the problem that the gram weight and air permeability of the existing non-woven fabric meet the requirements of people at present, but the difficulty is high if the two advantages need to be further improved. Comprising light-weight polyester yarn, a plurality of micropores are formed in the light-weight polyester yarn, and the micropores are of a porous structure which is irregularly distributed; comprising the following steps: selecting a chemical fiber raw material with a melting point lower than 120 DEG C, and stirring and mixing; the chemical fiber raw materials are put into the tank body to be heated, and the chemical fiber raw materials in the tank body are kept in a molten state. Air is injected after chemical fiber raw materials are melted, the chemical fiber raw materials are dissolved through air pressure changes, heating is conducted in the screw extruder to reduce the air solubility, tiny bubbles are generated, nascent fibers with micropores are formed, the light polyester yarn is manufactured, the raw material consumption is reduced, and the light weight and the structural strength are kept.

Description

Technical Field

[0001] The invention relates to the technical field of nonwoven fabrics, and in particular to a lightweight nonwoven fabric and a production method thereof. Background Art

[0002] Nonwoven fabric, also known as nonwoven fabric, is a kind of fabric that is not made by traditional textile methods. It forms a strong sheet material by mechanically, thermally or chemically bonding or interweaving fiber raw materials. The production process of nonwoven fabrics includes spunbond, meltblown, spunlace, needle punching and many other methods, each of which has its unique characteristics and application areas. This material is widely used in many industries such as medical, hygiene, filtration, agriculture, clothing, etc. due to its advantages such as light weight, durability, high cost-effectiveness and fast production speed. Nonwoven fabrics are also regarded as an environmentally friendly material because of their recyclability and biodegradability, which helps to reduce waste and promote sustainable development. With the advancement of technology, nonwoven fabrics are constantly innovating to meet the growing market demand and the pursuit of high-performance materials.

[0003] Nonwoven fabrics are often used as surgical gowns, masks, sanitary napkins and diapers, which require appropriate weight to ensure comfort during use, and good air permeability to keep dry and reduce bacterial growth. At the same time, disposable wet wipes and cosmetic cotton pads require good air permeability to dry quickly, and moderate weight to ensure sufficient absorbency and softness. For current nonwoven fabrics, the effects that can be achieved in terms of weight and air permeability have already met the current needs of people. If these two advantages need to be further improved, there is a high degree of difficulty. However, there is also a way in the prior art, that is, adding a microporous structure to the fiber, and then lightening the fiber, and finally reducing the weight of the nonwoven fabric formed by it, such as a highly uniform microporous nonwoven fabric and The preparation method and application thereof, the technical key points of which are: comprising the following steps: (1) using PET slices as raw materials, adopting a spunbond method to prepare a spunbond PET filament web as a support layer; (2) using meltblown PET slices or meltblown PBT slices as raw materials, adopting a meltblown spinning method to prepare a meltblown PET web or a meltblown PBT web as a meltblown layer; (3) subjecting the support layer prepared in step (1) and the meltblown layer prepared in step (2) to thermal setting to prepare an SM non-woven fabric or an SMS non-woven fabric; (4) using PET two-component staple fibers as raw materials, opening, combing into a web and hot rolling to prepare a staple web as a staple fiber layer; (5) placing the staple fiber layer prepared in step (4) on the SM non-woven fabric or the SMS non-woven fabric prepared in step (3), and subjecting the staple fiber layer to thermal setting and hot pressing to obtain a microporous non-woven fabric.

[0004] Now we provide another way to implement it.

[0005] Therefore, a lightweight nonwoven fabric and a production method thereof are proposed to solve or alleviate the above problems. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a lightweight non-woven fabric and a production method thereof.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A lightweight nonwoven fabric comprises lightweight polyester yarns. The lightweight polyester yarns have a plurality of micropores, and the plurality of micropores are irregularly distributed in a porous structure.

[0008] A method for producing a lightweight nonwoven fabric is also provided, for producing the lightweight nonwoven fabric, comprising the following steps: Step 1, selecting chemical fiber raw materials with a melting point lower than 120° C. for stirring and mixing; Step 2: putting the chemical fiber raw material into the tank body for heating, and keeping the chemical fiber raw material in the tank body in a molten state; Step 3, pressurizing air into the tank body through an air dissolving pump, so that the air is dissolved in the molten chemical fiber raw material in the tank body; Step 4, introducing the molten chemical fiber raw material containing dissolved air into the feed hopper of the screw extruder in batches, and keeping the tank sealed after each feeding; Step 5, extruding through a screw extruder, raising the temperature in the screw extruder, extruding through a spinneret, cooling the extruded primary fibers by water cooling, and then winding to form lightweight polyester yarns; Step 6, the lightweight polyester yarn is spread into a uniform fiber web by air flow or mechanical means, and the fiber web is sprayed with high-pressure water flow to form a lightweight non-woven fabric saturated with water; Step seven, the water-saturated lightweight non-woven fabric is sequentially dehydrated, dried, and finished before being rolled up to obtain the lightweight non-woven fabric.

[0009] Preferably, the discharge port of the screw extruder is connected to a spinneret, and the spinneret includes a spinneret with one end recessed to form a cavity, and the spinneret located on the side where the cavity is located is used for detachable connection with the discharge port of the screw extruder, and the end of the spinneret away from the screw extruder is provided with a spinneret hole connected to the cavity, the length of the spinneret hole is 60-120 cm, and a plurality of exhaust holes connected to the spinneret holes are provided on the outer peripheral wall of the spinneret.

[0010] Preferably, a support frame is provided on the outside of the screw extruder, a tank body is fixedly connected to the support frame, the tank body is connected to the feed hopper through a pipeline, the pipeline is connected to a solenoid valve, the tank body is detachably connected to a tank cover, the tank body comprises an inner tank and an outer tank, the inner tank and the outer tank are fixedly connected by a connecting block, and a accommodating cavity is formed therebetween, a heating wire is provided in the accommodating cavity and fits the outer peripheral wall of the inner tank, and the tank cover is connected to a pressurizing component.

[0011] Preferably, the pressurizing component comprises an air dissolving pump and a connecting pipe connected thereto, the other end of the connecting pipe passes through the tank cover, and the connecting pipe is sealed at the position where it passes through the tank cover.

[0012] Preferably, the accommodating cavity is filled with heat-insulating cotton wool.

[0013] Preferably, in step 5, the temperature in the screw extruder is 10-20° C. higher than the melting point of the chemical fiber raw material.

[0014] The present invention has the following beneficial effects: The production method of the present invention is to modify the chemical fiber raw material during hot melting. Different from the conventional chemical fiber preparation, in the present invention, after the chemical fiber raw material is melted, air is injected into it. This process utilizes the change of air pressure to dissolve or compress the air in the molten chemical fiber. When the molten chemical fiber raw material containing air is ready to be extruded in the screw extruder, we use the heating component inside the extruder to heat it. As the temperature rises, the solubility of air in the molten chemical fiber raw material decreases, resulting in the formation of countless tiny bubbles. After the bubbles leave the molten chemical fiber raw material under the influence of heating, they cannot dissolve again, so they will try to leave the molten chemical fiber raw material, so that hollow bubble spaces are formed in the molten chemical fiber raw material, and all of these bubble spaces are bubbles. These tiny bubbles gradually escape when being spun through the spinneret, so that the primary fibers have numerous micropores during the formation process. It is the existence of these micropores that gives the fibers an irregular porous structure, which has a significant impact on the performance of the polyester fibers. Through the process of the present invention, lightweight polyester yarns can be produced. Under the same length and thickness conditions, the amount of raw materials used for the polyester yarns is significantly reduced, while maintaining the light texture and original structural strength of the fibers, ultimately allowing the fibers to be processed in conjunction with the spunlace process to form the desired lightweight non-woven fabric.

[0015] In addition, the process of the present invention is highly controllable and can adjust the size and distribution of bubbles as needed, thereby precisely controlling the porous structure of the fiber, which not only improves the air permeability and moisture absorption of the fiber and non-woven fabric, but also brings about a wider expansion of the application areas of the fiber and non-woven fabric.

[0016] In summary, the process of the present invention not only improves the processing efficiency of chemical fiber raw materials, but also reduces the load of mechanical equipment during the production of non-woven fabrics, and reduces the gram weight of non-woven fabrics of the same area, making the non-woven fabrics more lightweight. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 This is a SEM photo of the cross section of the lightweight polyester yarn in the present invention; Figure 2 It is a structural schematic diagram of the screw extruder in the present invention; Figure 3 It is a structural schematic diagram of the spinneret in the present invention; Figure 4 It is a cross-sectional view of the spinneret in the present invention.

[0019] In the figure: 1, support frame; 2, tank body; 3, connecting pipe; 4, dissolved air pump; 5, feed hopper; 6, screw extruder; 7, spinneret; 9, exhaust hole; 10, cavity. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] In the description of the present invention, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the invention is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0024] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] A lightweight nonwoven fabric comprises lightweight polyester yarns. The lightweight polyester yarns have a plurality of micropores, and the plurality of micropores are irregularly distributed in a porous structure.

[0027] The present invention also provides a method for producing a lightweight nonwoven fabric, which is used to produce the lightweight nonwoven fabric, comprising the following steps: Step 1, selecting chemical fiber raw materials with a melting point lower than 120° C. for stirring and mixing; Step 2: putting the chemical fiber raw material into the tank body 2 for heating, and keeping the chemical fiber raw material in the tank body 2 in a molten state; Step 3, pressurizing air into the tank body 2 through the air dissolving pump 4, so that the air is dissolved in the molten chemical fiber raw material in the tank body 2; Step 4, introducing the molten chemical fiber raw material containing dissolved air into the feed hopper 5 of the screw extruder 6 in batches, and keeping the tank body 2 sealed after each introduction; Step 5, extruding through a screw extruder 6, raising the temperature in the screw extruder 6, extruding through a spinneret, cooling the extruded primary fibers by water cooling, and then winding to form lightweight polyester yarns; Step 6, the lightweight polyester yarn is spread into a uniform fiber web by air flow or mechanical means, and the fiber web is sprayed with high-pressure water flow to form a lightweight non-woven fabric saturated with water; Step seven, the water-saturated lightweight non-woven fabric is sequentially dehydrated, dried, and finished before being rolled up to obtain the lightweight non-woven fabric.

[0028] By going through the above steps, air can be injected into the chemical fiber raw material after it is melted, so that the air can be dissolved in the molten chemical fiber raw material under the change of air pressure, so that before the molten chemical fiber raw material containing air is about to be extruded in the screw extruder 6, the molten chemical fiber raw material containing air can be heated by the heating component in the screw extruder 6, and after the molten chemical fiber raw material containing air is heated, the solubility of air therein can be reduced, so that a number of tiny bubbles will be generated in the molten chemical fiber raw material containing air, and the tiny bubbles can escape during the spinning process of the spinneret, so that the nascent fiber formed by the molten chemical fiber raw material containing air after being ejected through the spinneret has a number of micropores, and the several micropores present an irregular porous structure, so that the final lightweight polyester yarn has less raw material usage and lighter texture under the same length and thickness, and the structural strength will not change much.

[0029] Preferably, the discharge port of the screw extruder 6 is connected to a spinneret, which includes a spinneret 7 with one end recessed to form a cavity 10. The spinneret 7 located on the side where the cavity 10 is located is used for detachable connection with the discharge port of the screw extruder 6, and a spinneret hole connected to the cavity 10 is provided at one end of the spinneret 7 away from the screw extruder 6, and the length of the spinneret hole is 60-120 cm. A plurality of exhaust holes 9 connected to the spinneret holes are provided on the outer peripheral wall of the spinneret 7.

[0030] When the spinneret is spinning, the molten chemical fiber raw material containing dissolved air can enter the cavity 10, and then enter the spinneret hole from the cavity 10. After further heating, the molten chemical fiber raw material containing dissolved air can release the air dissolved therein in the spinneret hole, and the air can leave through the exhaust hole 9. At the same time, the molten chemical fiber raw material containing dissolved air can be cooled and formed in the longer spinneret hole, so that it maintains its shape, and after leaving the spinneret hole, a relatively formed primary fiber can be obtained.

[0031] Preferably, a support frame 1 is provided on the outside of the screw extruder 6, and a tank body 2 is fixedly connected to the support frame 1. The tank body 2 is connected to the feed hopper 5 through a pipeline, and a solenoid valve is connected to the pipeline. The tank body 2 is detachably connected to a tank cover, and the tank body 2 includes an inner tank and an outer tank, and the inner tank and the outer tank are fixedly connected by a connecting block, and a accommodating cavity is formed between the two, and a heating wire is arranged in the accommodating cavity to fit the outer peripheral wall of the inner tank, and the tank cover is connected to a pressurizing component.

[0032] Preferably, the pressurizing component includes an air dissolving pump 4 and a connecting pipe 3 connected thereto, the other end of the connecting pipe 3 passes through the tank cover, and the connecting pipe 3 is sealed at the position where it passes through the tank cover.

[0033] Preferably, the accommodating cavity is filled with heat insulating cotton wool.

[0034] By filling the containing cavity with heat-insulating cotton wool, the heat overflow can be reduced during the heating process of the tank body 2, so that the chemical fiber raw material can be kept warm therein.

[0035] Preferably, in step 5, the temperature in the screw extruder 6 is 10-20° C. higher than the melting point of the chemical fiber raw material.

[0036] By making the temperature in the screw extruder 6 in step five higher than the melting point of the chemical fiber raw material by 10-20°C, it is possible to further heat the molten chemical fiber raw material containing dissolved air. At the same time, a higher temperature of 10-20°C can make the air dissolved in the molten chemical fiber raw material containing dissolved air less likely to dissolve therein, and can escape therefrom to form tiny bubbles.

[0037] The present invention adopts the production process of lightweight non-woven fabrics for processing, heats and melts the chemical fiber raw materials, and allows the introduction of air after melting. This process cleverly uses the change in air pressure to allow air to dissolve in the molten chemical fiber raw materials. Before the air-rich molten chemical fiber raw materials are ready to be extruded in the screw extruder 6, the present invention accurately heats them through the heating component in the extruder. As the temperature increases, the air solubility in the molten chemical fiber raw materials decreases, resulting in the formation of countless tiny bubbles therein. The purpose of precise heating is to make the change in the air solubility in the molten chemical fiber raw materials controllable and to enable the bubbles to leave in a regular manner.

[0038] These bubbles are gradually separated from the molten chemical fiber raw material when it is spun through the spinneret, which makes the primary fiber have numerous micropores during the formation process.

[0039] The presence of these micropores gives the fiber an irregular porous structure, which has a significant impact on the performance of the fiber. Through the process of the present invention, lightweight polyester yarn can be produced. Under the same length and thickness conditions, the amount of raw material used for this polyester yarn is significantly reduced, while maintaining the light texture and original structural strength of the fiber.

[0040] In addition, the process of the present invention is also highly controllable, and the size and distribution of bubbles can be adjusted as needed, so as to accurately control the porous structure of the fiber, which not only improves the air permeability and hygroscopicity of the fiber, but also brings a wider expansion of the application field of the fiber. Furthermore, the present invention can also use this lightweight polyester yarn to perform hydroentanglement processing on non-woven fabrics. This non-woven fabric not only inherits all the functional characteristics of lightweight polyester yarn, but also can significantly reduce the gram weight of the non-woven fabric under the condition of equal cross-sectional area. In the field of non-woven fabrics, which are already extremely light materials, the present invention achieves a more obvious weight reduction while ensuring the structural strength of the non-woven fabric.

[0041] The non-woven fabric made of lightweight polyester filaments has a further enhanced breathability. Even when it is stationary, the non-woven fabric can achieve air circulation inside and outside through the airways formed between the micropores. This feature makes the non-woven fabric not feel stuffy when it comes into contact with human skin, providing a more comfortable use experience.

[0042] In addition, the nonwoven fabric of the present invention also has excellent hygroscopic properties. Due to the microporous structure inside the fiber, the nonwoven fabric can quickly absorb and conduct moisture, and is suitable for occasions requiring good hygroscopicity, such as sanitary products, sportswear, etc. At the same time, this microporous structure can also provide a certain filtering function, making the nonwoven fabric also have potential application value in the fields of air filtration, water filtration, etc.

[0043] During the production process, the process of the present invention can also flexibly adjust the porous structure of the fiber and the performance of the non-woven fabric according to specific application requirements. For example, by adjusting parameters such as the heating temperature, the screw extrusion speed, and the spinneret aperture, fibers and non-woven fabrics with different aperture sizes, porosities, and mechanical properties can be produced to meet the needs of different industries and markets.

[0044] In summary, the products of the present invention have excellent air permeability, moisture absorption and filtration performance while maintaining a light texture and good structural strength, opening up new possibilities for the application of textile materials. Through the process of the present invention, lightweight polyester yarns and non-woven fabrics with better performance and wider applications can be produced to meet the market demand for high-performance fiber materials.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A lightweight nonwoven fabric, characterized in that: The invention comprises a lightweight polyester yarn, on which a plurality of micropores are present, and the plurality of micropores are in an irregularly distributed porous structure.

2. A method for producing a lightweight nonwoven fabric, for producing the lightweight nonwoven fabric as claimed in claim 1, characterized in that: The steps include: Step 1, selecting chemical fiber raw materials with a melting point lower than 120° C. for stirring and mixing; Step 2: putting the chemical fiber raw material into the tank body (2) for heating, and keeping the chemical fiber raw material in the tank body (2) in a molten state; Step three, pressurizing air into the tank body (2) through the air dissolving pump (4), so that the air is dissolved in the molten chemical fiber raw material in the tank body (2); Step 4, introducing the molten chemical fiber raw material containing dissolved air into the feed hopper (5) of the screw extruder (6) in batches, and keeping the tank body (2) sealed after each introduction; Step 5, extruding through a screw extruder (6), raising the temperature in the screw extruder (6), extruding through a spinneret, cooling the extruded nascent fibers by water cooling, and then winding to form lightweight polyester filaments; Step 6, the lightweight polyester yarn is spread into a uniform fiber web by air flow or mechanical means, and the fiber web is sprayed with high-pressure water flow to form a lightweight non-woven fabric saturated with water; Step seven, the water-saturated lightweight non-woven fabric is sequentially dehydrated, dried, and finished before being rolled up to obtain the lightweight non-woven fabric.

3. The method for producing a lightweight nonwoven fabric according to claim 2, characterized in that: The discharge port of the screw extruder (6) is connected to a spinneret, the spinneret comprising a spinneret (7) with one end recessed to form a cavity (10), the spinneret (7) located on the side where the cavity (10) is located being used for being detachably connected to the discharge port of the screw extruder (6), and a spinneret hole connected to the cavity (10) is provided at one end of the spinneret (7) away from the screw extruder (6), the length of the spinneret hole being 60-120 cm, and a plurality of exhaust holes (9) connected to the spinneret hole are provided on the outer peripheral wall of the spinneret (7).

4. The method for producing a lightweight nonwoven fabric according to claim 3, characterized in that: A support frame (1) is arranged outside the screw extruder (6), a tank body (2) is fixedly connected to the support frame (1), the tank body (2) is connected to the feed hopper (5) through a pipeline, the pipeline is connected to a solenoid valve, the tank body (2) is detachably connected to a tank cover, the tank body (2) comprises an inner tank and an outer tank, the inner tank and the outer tank are fixedly connected by a connecting block, and a receiving cavity is formed between the two, a heating wire is arranged in the receiving cavity and is in contact with the outer peripheral wall of the inner tank, and the tank cover is connected to a pressurizing component.

5. The method for producing a lightweight nonwoven fabric according to claim 4, characterized in that: The pressurizing component comprises an air dissolving pump (4) and a connecting pipe (3) connected thereto, the other end of the connecting pipe (3) passes through the tank cover, and the connecting pipe (3) is sealed at the position where it passes through the tank cover.

6. The method for producing a lightweight nonwoven fabric according to claim 4, characterized in that: The accommodating cavity is filled with heat-insulating cotton wool.

7. The method for producing a lightweight nonwoven fabric according to claim 2, characterized in that: In step 5, the temperature in the screw extruder (6) is 10-20° C. higher than the melting point of the chemical fiber raw material.

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