JP5661879B1 - Lightweight felt material - Google Patents

Abstract

The present invention provides a lightweight felt material that has high sound absorption and flame retardancy, is flexible, and is suitable for automobiles and vehicle interior materials, industrial materials, clothing, and the like. In a lightweight felt material, two hard cotton layers are 20 to 80% ultrafine fibers each having a fineness of 1.1 dtex or less, 10 to 60% hollow fibers imparting bulkiness, and are melted during the entire heat treatment. 10 to 60% of low melting point fibers are mixed, the fiber diameter of the nonwoven sheet is 2 to 20 μm, and the basis weight is 20 to 100 g / m 2. [Selection] Figure 1

Description

  The present invention relates to a lightweight felt material that has high sound absorption and flame retardancy, is flexible, and is suitable for automobiles and vehicle interior materials, industrial materials, clothing, and the like.

In general, an interior material is attached to an automobile in a trunk room or a luggage room, and a skin sheet having a soft velor-like or dilore-like texture is often used as the interior material. The surface sheet is constant intensity by bonding to the plastic or felt sheet on the lower side, to enhance the sound absorption and reduce the noise entering from the trunk room to the cabin, and further increase the rigidity and formability of the skin material However, it has been quite difficult to obtain a desired three-dimensional shape in the past.

  In order to obtain a desired three-dimensional shape, the present applicant has already sold an interior material in which a plain type skin material and a felt sheet are entangled and integrated by needle punching and then heat-press molded. Further, in Patent No. 5027456, when a spunbond nonwoven fabric integrated with a felt sheet is used, and the granular melt is dispersed and formed by preheating treatment on the entire surface of the spunbond nonwoven fabric, A spunbonded nonwoven fabric can be molded by being melted on the surface and bonded to a skin material. Since this felt material for interior materials can be formed by cold pressing, the surface of the skin material is not heated and pressurized, and thus an interior material that retains the color and nap of the skin can be obtained.

  The felt sheet is generally produced by blending ordinary polyester fibers and low-melting polyester fibers and further integrating them with a needle punch. Since this felt sheet has a relatively high fineness of the fibers used, the sound absorbing performance cannot be increased so much, and the fibers are shifted in the thickness direction by the needle punch, and the overall sound absorbing performance is inevitably lowered. In contrast, JP-A-53-41577, JP-A-6-212545 and JP-A-6-212546 provide a melt-blown nonwoven fabric (trade name: cinsalate) using ultrafine fibers and polyester short fibers, The nonwoven fabric is suitable as an interior material because it has high sound absorption and is flexible and easy to process.

Japanese Patent No. 5027456 JP-A-53-41577 JP-A-6-212545 JP-A-6-212546

  Melt blown non-woven fabrics are produced, for example, by integrating ultrafine fibers with an average fiber diameter of 10 μm or less spun by a melt blown method and polyester short fibers such as flame retardancy, and are generally quite excellent in sound absorption and heat insulation. . Melt blown non-woven fabrics are both lightweight and bulky, and are suitable not only as sound absorbing materials but also as heat insulating materials. At present, however, users are required to propose higher performance interior materials.

  Melt-blown nonwoven fabrics are used as automobile roof sheets in certain vehicle types by bonding a skin material such as spunlace to the front and back surfaces. In this roof sheet, spun laces on the front and back surfaces are bonded, and the spun lace tends to be wrinkled, making it difficult to fit the shape of the interior surface. It is pointed out that this roof sheet is more difficult to fit to the shape of the interior surface because the cut end face may adhere to the cutter when removing the shape with a Thomson cutter.

  The present invention has been proposed to further improve conventional automotive interior materials, and provides a lightweight felt material excellent in sound absorption and flame retardancy, and having a good balance of thickness, weight and density. It is an object. Another object of the present invention is to provide a lightweight felt material suitable not only for interior materials for automobiles and vehicles, but also for industrial materials and cold clothing.

The lightweight felt material according to the present invention is integrated by interposing a nonwoven sheet between two hard cotton layers. In this lightweight felt material, in both hard cotton layers, ultrafine fibers having a fineness of 1.1 dtex or less are 20 to 80%, hollow fibers imparting bulkiness are 10 to 60%, and low melting point fibers that are melted during the entire heat treatment are 10 to 10%. 60% is blended, the fiber diameter in the nonwoven sheet is 2 to 20 μm, and the basis weight is 20 to 100 g / m ² .

The lightweight felt material according to the present invention is integrated by thermocompression bonding with a non-woven sheet interposed between two hard cotton layers. In this lightweight felt material, in both hard cotton layers, preferably 20 to 80% ultrafine fibers having a fineness of 1.1 dtex or less, 10 to 30% hollow fibers imparting bulkiness, and low melting point fibers that melt during the overall heat treatment 10 to 60% may be blended, the fiber diameter in the nonwoven sheet may be ² to 20 μm, and the basis weight may be 20 to 100 g / m ² .

  In the lightweight felt material of the present invention, the ratio of the thickness of the upper hard cotton layer to the lower hard cotton layer is preferably 1: 1 to 1: 4, and the nonwoven sheet is a nonwoven fabric produced by a melt blown method. And preferred. Further, the hard cotton layer may further contain 10 to 30% of a short fiber or a repellent of a synthetic fiber having a normal fineness.

  In the method for producing a lightweight felt material according to the present invention, a non-woven sheet is placed on a traveling conveyor followed by a first web entangled with ultrafine fibers, hollow fibers, and low-melting fibers. And forming a three-layer laminate by placing a second web entangled with low-melting fibers, and then heat-treating and pressurizing the three-layer laminate at a temperature exceeding the melting point of the low-melting fibers. Achieve integration at the same time. In this production method, it is preferable to bond the nonwoven sheet and the first and second webs more reliably by fuzzing both surfaces of the nonwoven sheet by embossing at a low temperature or brushing the surface.

  The lightweight felt material according to the present invention is a composite material of a hard cotton layer and a non-woven sheet, and is relatively cheaper and more excellent in sound absorption and flame retardancy than an existing meltblown nonwoven fabric. The lightweight felt material of the present invention is flexible and easy to fit on the inner surface of a vehicle, and is not only used for automobiles and vehicle interior materials, but also for industrial materials such as soundproofing and heat insulating materials, heat insulation materials for ski wear, gloves, It can also be applied to cold clothing such as padded hats.

  The light weight felt material according to the present invention has a weight per unit area, thickness and density equivalent to those of an existing meltblown nonwoven fabric, has high sound absorption performance and flame retardancy suitable for FMVSS302, and has a good balance of thickness, weight and density. Specifications have been established. The lightweight felt material of the present invention is advantageous in terms of cost because it does not require an adhesive material during production, and can be advantageously used as an alternative to existing meltblown nonwoven fabrics by adjusting the sound absorption performance and flame retardancy as appropriate. is there.

  Since the manufacturing method of the lightweight felt material which concerns on this invention laminates | stacks a 1st web, a nonwoven sheet, and a 2nd web and heat-processes and integrates it, it is possible to batch-produce a lightweight felt material in one line. . If the manufacturing method of this invention is utilized, a lightweight felt material can be manufactured efficiently and the reduction of manufacturing cost will be attained. Moreover, if both surfaces of the nonwoven sheet are fluffed in advance, the peel strength of the entire felt material can be increased.

It is an expanded sectional view showing the lightweight felt material concerning the present invention. It is an expanded sectional view showing a modification of a lightweight felt material. It is a schematic side view which illustrates the manufacturing process of a lightweight felt material. It is a fragmentary perspective view which decomposes | disassembles and shows a three-layer laminated body. It is a graph which displays the felt material of Example 2, Example 3, and the sound absorption rate of comparison AC. It is a graph which displays the felt material of Example 5, Example 6, and the sound absorption rate of the comparison D.

  The lightweight felt material 1 according to the present invention is integrated with a nonwoven sheet 5 interposed between two hard cotton layers 2 and 3 as shown in FIG. The hard cotton layers 2 and 3 usually have the same thickness, density, and basis weight distribution, and the sound absorbing performance of the felt material 1 may be further enhanced by appropriately adjusting the thicknesses of both as desired. When used as an interior material, the felt material 1 is further bonded with a skin material having a suitable appearance, tactile sensation, fuzziness, etc. at normal temperature or heat treatment.

  The lightweight felt material 1 generally has a three-layer structure as illustrated, and the hard cotton layer itself may be a plurality of layers. Moreover, the lightweight felt material 1 may arrange two nonwoven sheets in each of three layers of hard cotton layers, or may arrange three nonwoven sheets in each of four layers of hard cotton layers. In order to increase the adhesive strength between the nonwoven sheet and the hard cotton layer, it is possible to spray an adhesive powder in an amount that does not impair the sound absorbing performance or to apply an adhesive liquid between them.

  The hard cotton layers 2 and 3 are formed by entanglement of 20 to 80% of ultrafine fibers, 10 to 60% of hollow fibers, and 10 to 60% of low melting point fibers, and synthetic fibers having normal fineness may be appropriately added. The hard cotton layers 2 and 3 usually have the same fiber composition, but can be changed according to the use of the felt material 1. The ultrafine fibers, hollow fibers, and synthetic fibers having normal fineness are polyester, acrylic, polyamide, rayon, polypropylene, polyvinyl chloride, polyethylene, and the like. From the viewpoints of cost and heat resistance, it is preferable that all of the ultrafine fiber, hollow fiber, low melting point fiber and normal synthetic fiber are polyester.

  In the hard cotton layers 2 and 3, the ultrafine fiber means a fiber having a fineness of 1.1 dtex (1 denier) or less, which is difficult to spin normally. In the present invention, the ultrafine fiber and the ultrafine fiber are included. In order to produce short ultrafine fibers, a melt blow method, a centrifugal spinning method, a flash spinning method, a beating method, a mixed spinning method, a tag spinning method, or the like is used. The addition amount of the ultrafine fiber is 20 to 80% by weight, and preferably 40 to 80% by weight of a relatively large number of eyes. If the amount of extra fine fibers is less than 20%, it is difficult to improve the sound absorbing performance of the felt material 1, while if it exceeds 80%, it is difficult and uneconomical to make the felt material 1 bulky.

  In the hard cotton layers 2 and 3, the hollow fiber is produced using a special spinning nozzle in melt spinning of polyester, acrylic, polyamide, etc. as a kind of irregular cross-section fiber, or in the case of rayon spinning. A bubble having a hollow cross section can be produced by generating bubbles inside the fiber. This hollow fiber has a large apparent fineness and a tight crimp, generally has good heat retention and is light, and strengthens the felt material. The addition amount of the hollow fiber is 10 to 60% by weight, and preferably 10 to 30% by weight that can impart bulkiness. When adding less than 10% of hollow fibers, it is difficult to impart bulkiness to the felt material 1, while when it exceeds 60%, the flexibility of the felt material 1 is impaired.

  In the hard cotton layers 2 and 3, the low melting point fiber has a melting point of about 40 to 70 ° C. lower than that of the ultrafine fiber, the hollow fiber, and the synthetic fiber having the normal fineness, and the whole integrated and non-woven sheet 5 as a binder in the heat treatment Contributes to adhesion. Examples of the low melting point fiber include low melting point polyester, low melting point polyamide, polyethylene, and polypropylene, and may be a copolymer with ethylene or butene. As long as the low melting point fiber has a lower melting point than that of a normal fiber, a known fiber, a resin filament, or a mixed fiber having a melting point of 90 to 170 ° C. can be used. Fiber is also preferred. The addition amount of the low melting point fiber is 10 to 60% by weight, and preferably 20 to 50% by weight, which facilitates the integration of the whole. If the low melting point fiber is less than 10%, it becomes difficult to integrate the felt material 1 or adhere to the non-woven sheet 5 by heat treatment, while if it exceeds 60%, the entire felt material 1 becomes too hard.

  When the low melting point fiber is a core-sheath structure polyester fiber, the sheath fiber may be a low melting point polyester having a melting point of 110 ° C., 130 ° C., 150 ° C., 160 ° C. or the like. The core fiber is regular polyester having a melting point of 250 ° C. When the core / sheath PP / PE fiber is used, the sheath fiber is polyethylene having a melting point of 130 to 134 ° C., and the core fiber is polypropylene having a melting point of 165 ° C. Even if the core-sheath structure PP / PE fiber can be used at a relatively low cost, the binder effect is small and the resilience is slightly inferior to the core-sheath structure polyester fiber.

  The hard cotton layers 2 and 3 may further contain 10 to 30% of short fibers of synthetic fibers having a normal fineness or various repellents (recovered recycled cotton) in addition to the above-mentioned fibers. This is done mainly for cost reduction, and the addition amount is limited to a range where the sound absorption performance is not lowered. In terms of cost, it is advantageous to add a bristles, and the lightweight felt material 1 can be manufactured at a very low cost.

  In the lightweight felt material 1, the upper hard cotton layer 2 and the lower hard cotton layer 3 usually have the same thickness and density. Also, like the lightweight felt material 6 shown in FIG. 2, the thickness ratio of the hard cotton layers 2 and 3 can be changed to 1: 4, preferably 1: 2.2 in order to further improve the sound absorption performance. Even if the thickness ratio is increased further, the sound absorbing performance is hardly improved. If the thicknesses of the hard cotton layer 2 and the hard cotton layer 3 are different, it is necessary to arrange so that sound enters from the thinner hard cotton layer 2 side. If it enters, the sound absorption performance of the felt material 1 will fall.

In the upper hard cotton layer 2, it is usually desirable that the thickness is 10 to 19 mm and the basis weight is 100 to 300 g / m ² , and a preferable specification is a thickness of about 12 mm and a basis weight of about 177 g / m ² . On the other hand, the lower hard cotton layer 3, typically, it is desirable thickness is 19~30mm and basis weight is 100 to 300 g / ^{m 2,} preferred specifications is about thick 25 mm, basis weight of about 123 g / ^{m 2.}

  The nonwoven sheet 5 is desirably composed of ultrafine fibers having a fiber diameter of 2 to 20 μm, and the nonwoven sheet can be produced by the above-described methods, and is preferably produced by a melt blown method. The meltblown nonwoven sheet 5 is low in density and bulky, and has a high drape and is flexible. In the meltblown nonwoven sheet 5, a plurality of adjacent single fibers are bundled in the web to form a connecting portion in which at least a part in the fiber length direction is bonded to each other. For example, in a meltblown nonwoven sheet, a kneaded resin is extruded from a nozzle onto a conveyor while blowing hot air, and the ultrafine fibers are entangled with heat to form a sheet. In the meltblown nonwoven sheet, it is desirable that the connecting fibers including the connecting portions are bonded at the intersections with the fibers constituting the meltblown web.

The non-woven sheet 5 is a relatively thin non-woven fabric having a thickness of 0.1 to 1.0 mm and rich in drape, and preferably has a basis weight of 20 to 100 g / m ^2. The thickness is about 0.3 mm and the basis weight is about 40 g / m ² . Can not be sufficiently increased basis weight sound absorbing performance of the felt material 1 is less than 30 g / m ² nonwoven sheet 5, while flexibility on top even exceed 100 g / m ² less improvement in sound absorbing performance Is prone to decline.

  The ultrafine fibers constituting the non-woven sheet 5 are made of polyester, acrylic, polyamide, polypropylene, polyethylene, polyvinyl chloride, or the like, and is generally preferably polyester from the viewpoint of cost and heat resistance. This ultrafine fiber may be sprayed with a flame retardant or may be immersed in a solution of the flame retardant after forming the sheet. This flame retardant is also possible for the hard cotton layers 2 and 3.

  In order to continuously manufacture the lightweight felt material 1, a felt manufacturing apparatus 7 having a combined arrangement schematically illustrated in FIG. 3 may be used. The conveyor 8 usually has a net-like structure through which hot air and cold air can pass, and travels over the entire length of the felt manufacturing apparatus 7. Adjacent first and second card / cross wrappers 10 and 12 form an accumulation layer by mixing ultrafine fibers, hollow fibers and low melting point fibers with a known card machine, and this accumulation layer is overlapped with the cross wrapper. Thus, webs 14 and 16 (see FIG. 4) having a predetermined thickness are obtained.

  In the long non-woven sheet 5, the sheet winding roll 18 is horizontally installed between the card / cross wrappers 10 and 12, and is sent out from the winding roll onto the conveyor 8. On the other hand, the long non-woven sheet 5 can be fed from outside the apparatus via a plurality of rollers 20. If both surfaces of the non-woven sheet 5 are fluffed in advance by embossing at a low temperature or surface brushing, the non-woven sheet and the first and second webs can be more reliably bonded.

  The heat treatment machine 22 is installed behind the second card / cross wrapper 12 and is heated by the hot air circulating in the machine to form a three-layer laminate 24 of the second web 16, the non-woven sheet 5 and the first web 14 (see FIG. 4). Is uniformly heated on the conveyor 8. This heating temperature needs to exceed the melting point of the low-melting fibers in the webs 14 and 16, thereby melting the low-melting fibers. A pair of pressure rollers 26 and a cooler 28 are sequentially installed behind the heat treatment machine 22. The lightweight felt material 1 is obtained from the three-layer laminate 24 by the heat treatment machine 22 and the pair of pressure rollers 26.

  In the felt manufacturing apparatus 7, first, ultrafine fibers, hollow fibers, low melting point fibers, and the like are entangled by the first card / cross wrapper 10, and the first web 14 corresponding to the lower hard cotton layer 3 is sent out onto the conveyor 8. Next, the long nonwoven sheet 5 is continuously placed on the first web 14 on the conveyor 8. In the second card / cross wrapper 12, a predetermined amount of ultrafine fibers, hollow fibers, low melting point fibers, and the like are entangled, and the second web 16 corresponding to the upper hard cotton layer 2 is fed onto the conveyor 8, and a non-woven sheet is obtained. 5 to form a three-layer laminate 24.

  The three-layer laminate 24 (see FIG. 4) that has passed through the second card / cross wrapper 12 is uniformly heated on the conveyor 8 in the heat treatment machine 22 and further pressed by a pair of pressure rollers 26 to be entirely Feltization and integration are achieved simultaneously, and the lightweight felt material 1 is continuously produced. The obtained lightweight felt material 1 passes through the cooler 28 and is cooled by the cold air descending in the cooler.

The obtained lightweight felt material 1 generally has a thickness of 8 to 50 mm and a basis weight of 300 to 500 g / m ² , and suitable specifications are a thickness of about 38 mm and a basis weight of about 340 g / m ² . In special applications, the thickness is possible up to about 100 mm, basis weight is the upper limit of 3000 g / ^{m 2} approximately, the density is lower limit 0.005 g / cm ^3, the upper limit is 0.043 g / cm ³ or more even Is possible.

As an example of general specifications of the lightweight felt material 1, the density is set to 0.0425 g / cm ³ when the thickness is 8 mm and the weight per unit area is 340 g / m ² . When a thick 10~40mm with basis weight 340 g / ^{m 2,} a density in thickness 10mm 0.0340g / cm ^3, the density in the thickness 15mm 0.0227g / cm ^3, density of 0.0170g / cm ³ with a thickness of 20mm When the thickness is 25 mm, the density is 0.0136 g / cm ^{3. When} the thickness is 30 mm, the density is 0.0113 g / cm ^{3. When} the thickness is 35 mm, the density is 0.0001 g / cm ^{3. When} the thickness is 40 mm, the density is 0.0076 g / cm ³ . . Moreover, basis weight 425 g / ^{m 2} with a thickness 50 mm, basis weight 510 g / ^{m 2} with a thickness 60 mm, basis weight 595 g / ^{m 2} with a thickness 70 mm, basis weight 680 g / ^{m 2} with a thickness 80 mm, basis weight 850 g / m in thickness 100mm ^When it is ² , the density becomes 0.0076 g / cm ³ .

Next, the present invention will be described based on examples, but the present invention is not limited to the examples. In order to manufacture the lightweight felt material 1 shown in FIG. 1, the felt manufacturing apparatus 7 shown in FIG. 3 is used, 40% of fine polyester fiber having a fineness of 0.75 denier, 15% of hollow polyester fiber having a fineness of 15 denier, and 4 denier of fineness. 25% low-melting polyester fibers and 20% polyester short fibers having a fineness of 3 denier are mixed to form two webs 14 and 16 having a basis weight of 150 g / m ² . As the nonwoven sheet 5, a polyester melt blown sheet (trade name: Kuraflex BTS0040EM, manufactured by Kuraray Co., Ltd.) having a basis weight of 40 g / m ² is used.

The nonwoven sheet 5 is sandwiched between the webs 14 and 16, and the whole is heated and bonded. The obtained lightweight felt material 1 has the non-woven sheet 5 positioned at the center of the felt material, and the thickness and basis weight distribution of the upper and lower hard cotton layers 2 and 3 are equal. This lightweight felt material 1 has a thickness of 38 mm and a basis weight of 340 g / m ² .

Using a test machine, a lightweight felt material 1 having the same fiber composition as in Example 1 is manufactured using polyester repellents instead of polyester short fibers having a fineness of 3 denier in Example 1. In this lightweight felt material 1, the upper hard cotton layer 2 has a thickness of 19 mm and a basis weight of 155 g / m ² , while the lower hard cotton layer 3 has a thickness of 19 mm and a basis weight of 155 g / m ² . .

The obtained lightweight felt material 1 has a thickness of 38 mm and a basis weight of 350 g / m ² . Considering the cost, if it is about 20%, polyester fluff can be added instead of polyester short fibers.

Using the felt manufacturing apparatus 7 shown in FIG. 3, the webs 14 and 16 have the same fiber composition as that in Example 1, and the webs 14 and 16 sandwich the non-woven sheet 5 same as that in Example 1 and heat-bond the whole. A lightweight felt material 1 is manufactured. The obtained lightweight felt material 1 has a thickness of 38 mm and a basis weight of 407 g / m ² .

About the lightweight felt material 1 which is Example 2 and Example 3, it compares with the following product.
Comparison A: Melt blown non-woven fabric with a thickness of 38 mm (trade name: Shinsarate TC3303 300)
(Weight per unit of 356 g / m ² )
Comparison B: 38mm thick melt blown nonwoven fabric (trade name: Thinsulate regular 300)
Comparative C: Felt material having the same fiber composition as in Example 3 and having no non-woven sheet 5 interposed (thickness 38 mm and basis weight 386 g / m ² )

  The lightweight felt material 1 of Examples 2 and 3 and the comparisons A to C all have a thickness of 38 mm. With respect to these products, sound absorption data by the normal incidence method was measured, and the results are shown in Table 1 below.

  FIG. 5 is a graph showing the results of Table 1. From this graph, it is clear that the lightweight felt material 1 of Examples 2 and 3 has a sound absorption coefficient equal to or higher than that of comparisons A and B, which are known melt blown nonwoven fabrics (trade name: cinsalate). Further, from the sound absorption coefficient of Comparative C, the nonwoven sheet 5 is essential in the lightweight felt material of the present invention.

Using the felt manufacturing apparatus 7 shown in FIG. 3, the webs 14 and 16 have the same fiber composition as that in Example 1, and the webs 14 and 16 sandwich the non-woven sheet 5 same as that in Example 1 and heat-bond the whole. A lightweight felt material 6 (FIG. 2) is manufactured. In the lightweight felt material 6, the upper hard cotton layer 2 has a thickness of 12 mm and a basis weight of 202 g / m ² , while the lower hard cotton layer 3 has a thickness of 26 mm and a basis weight of 165 g / m ² .

The light weight felt material 6 having different thicknesses of the hard cotton layers 2 and 3 is different in the weight distribution and the total weight is heavier by about 50 g / m ^2, but compared with the light weight felt material 1 having the same thickness of the hard cotton layers 2 and 3. Sound absorption performance is greatly increased.

A lightweight felt material 1 is produced with the same fiber composition as in Example 1. However, the obtained lightweight felt material 1 has a thickness of 20 mm and a basis weight of 327 g / m ² .

A lightweight felt material 1 is produced with the same fiber composition as in Example 2. However, the obtained lightweight felt material 1 has a thickness of 20 mm and a basis weight of 333 g / m ² .

About the lightweight felt material 1 which is Example 5 and Example 6, it compares with the following product.
Comparison D: Melt blown non-woven fabric with a thickness of 20 mm (trade name: Thinsulate TC3303 300)
(Weight per unit of 326 g / m ² )

  Both the lightweight felt material 1 and the comparative D of Example 5 and Example 6 have a thickness of 20 mm. For these products, the sound absorption data by the normal incidence method was measured, and the results are shown in Table 2 below.

  FIG. 6 is a graph showing the results of Table 2. From this graph, it is clear that the lightweight felt material 1 of Examples 5 and 6 has a sound absorption coefficient equal to or higher than that of Comparative D, which is a known melt blown nonwoven fabric (trade name: Thinsulate), even at a thickness of 20 mm.

1 Lightweight felt material
2 Upper hard cotton layer 3 Lower hard cotton layer 5 Non-woven sheet

Claims (7)

A lightweight felt material in which a nonwoven sheet is interposed between two hard cotton layers to integrate the whole, and both hard cotton layers have a fine fiber of 20 to 80% and a bulkiness of 1.1 dtex or less. 10 to 60% of hollow fibers imparting the properties, 10 to 60% of low melting point fibers that melt during the entire heat treatment are mixed, the fiber diameter in the nonwoven sheet is 2 to 20 μm, and the basis weight is 20 to 100 g / m ² Lightweight felt material for some interior materials. An ultra-fine fiber 20 which is a bulky lightweight felt material in which a nonwoven sheet is interposed between two hard cotton layers and the whole is integrated by thermocompression bonding. 80%, 10-30% hollow fibers imparting bulkiness, 10-60% low melting point fibers that melt during the entire heat treatment are blended, and the fiber diameter in the non-woven sheet is 2-20 μm, and the basis weight is 20-20. Lightweight felt material for interior materials that is 100 g / m ² .   The lightweight felt material according to claim 1 or 2, wherein the thickness ratio of the upper hard cotton layer to the lower hard cotton layer is 1: 1 to 1: 4.   The lightweight felt material according to claim 1 or 2, wherein the nonwoven sheet is a non-woven fabric produced by a melt blown method. Hardness in cotton layer, according to claim 1 or 2 lightweight felt material according contain further 10-30% short fibers or garnetted stock of synthetic fibers.   A non-woven sheet is placed on a traveling conveyor followed by a first web entangled with ultrafine fibers, hollow fibers, and low-melting fibers, and a second web entangled with ultrafine fibers, hollow fibers, and low-melting fibers. A method for producing a lightweight felt material that forms a three-layer laminate and then heat-treats and pressurizes the three-layer laminate at a temperature exceeding the melting point of the low-melting fiber to simultaneously achieve the entire felt and integration. . By fuzz on both sides of the nonwoven sheet in brushing of embossing processing or surface, nonwoven sheet and production method of claim 6 wherein more reliably bond the first and second webs.

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