KR20160045619A - Lightweight felts - Google Patents

Abstract

(assignment)
Sound-absorbing property and flame retardancy and is flexible, and provides a lightweight felt material suitable for automobiles, vehicle interior materials, industrial materials, clothing materials, and the like.
(Solution)
In the lightweight felt material, the two-layered mirror-surface layer is composed of 20 to 80% of microfine fibers having a fineness of 1.1 dtex or less, 10 to 60% of hollow fibers imparting balquing property, To 60% are mixed, and the nonwoven sheet has a fiber diameter of 2 to 20 占 퐉 and a basis weight of 20 to 100 g / m2.

Description

Lightweight felt material {LIGHTWEIGHT FELTS}

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

In automobiles, an interior material is usually adhered to a trunk room, a rugby room, and the like. In this case, a velor-like or dilor-like skin sheet having a soft touch is often used. This skin sheet is adhered to the plastic or felt sheet under the skin material to increase the sound absorption property to reduce the noise penetrating into the vehicle room from the trunk room and to increase rigidity and moldability to maintain constant strength , It has conventionally been difficult to obtain a desired three-dimensional shape.

In order to obtain a desired three-dimensional shape, the present applicant has already sold an interior material in which a planar type skin material and a felt sheet are intertwined by needle punching, integrated, and then subjected to heat press molding. Japanese Patent No. 5027456 discloses a spunbonded nonwoven fabric that is integrated with a felt sheet and that the granular molten material on the entire surface of the spunbonded nonwoven fabric is dispersed The spunbonded nonwoven fabric can be surface-melted and bonded to the skin material to be molded and processed. Since the felt material for the interior material can be formed by a cold press, the surface of the skin material is not heated or pressed, so that an interior material that maintains the color of the skin and the nap sensation can be obtained.

The above-mentioned felt sheet is generally produced by mixing ordinary polyester fibers and low-melting-point polyester fibers with one another by needle punching. This felt sheet can not have a high sound absorption performance because the fiber used has a high degree of fineness, so that the fibers are shifted in the thickness direction by needle punching, and the overall sound absorption performance is inevitably lowered inevitably. On the other hand, Japanese Patent Application Laid-Open No. 53-41577, Japanese Patent Application Laid-Open Nos. 6-212545 and 6-212546 disclose melt-blown methods using microfibers and polyester staple fibers ) Nonwoven fabric (trade name: THINSULATE), and the nonwoven fabric is suitable as an interior material since it is highly sound-absorbing and is flexible and easy to process.

Japanese Patent No. 5027456 Japanese Patent Application Laid-Open No. 53-41577 Japanese Patent Application Laid-Open No. 6-212545 Japanese Patent Application Laid-Open No. 6-212546

The meltblown nonwoven fabric is produced by integrating, for example, ultrafine fibers having an average fiber diameter of 10 占 퐉 or less and polyester short fibers such as flame retardancy, which are spun by the meltblown method, Sound absorption and heat insulation. The meltblown nonwoven fabric is lightweight and has a large volume and is suitable as a heat insulating material as well as a sound absorbing material. However, at present, it is demanded by users to offer a higher performance interior material.

In addition, the meltblown nonwoven fabric is adhered with a skin material such as spun lace to its front and back surfaces, and is used as a vehicle roof sheet in some types of vehicles. In this loop sheet, sponges or the like of its top and bottom surfaces are adhered, and this spun lace tends to be wrinkled, making it difficult to fit the shape of the inner scene. It is pointed out that this loop sheet is more difficult to fit the shape of the inner scene, because the cut surface may adhere to the cutter when cutting the shape with the Thomson cutter.

The present invention has been proposed in order to further improve a conventional automotive interior material, and aims to provide a lightweight felt material excellent in sound absorption and flame retardancy, and further balanced in thickness, weight and density. It is another object of the present invention to provide a lightweight felt material suitable not only for automobiles and automobile interior materials, but also for industrial materials, winter clothes, and the like.

The lightweight felt material according to the present invention integrates the entirety by interposing a nonwoven sheet between two hard surface layers (hard cotton layers). In this lightweight felt material, in both of the specular surface layers, 20 to 80% of microfine fibers having a fineness of 1.1 decitex or less, 10 to 60% of hollow fibers giving bulkiness, and low melting point fibers 10 to 60% of the fibers are mixed and the fibers have a diameter of 2 to 20 占 퐉 and a basis weight of 20 to 100 g / m2 in the nonwoven sheet.

The lightweight felt material according to the present invention has a nonwoven sheet interposed between two mirror-surface layers, and the whole is integrated by thermocompression bonding. In this lightweight felt material, in both of the specular surface layers, 20 to 80% of microfine fibers having a fineness of 1.1 decitex or less, 10 to 30% of hollow fibers giving glue property, and low melting point fibers 10 to 60% of the fibers are blended, and the nonwoven sheet may have a fiber diameter of 2 to 20 占 퐉 and a basis weight of 20 to 100 g / m2.

In the lightweight felt material of the present invention, the ratio of the thickness of the upper (upper) specular layer to the thickness of the lower (lower) specular layer is preferably from 1: 1 to 1: 4, Nonwoven fabrics are preferred. In the specular surface layer, 10 to 30% of synthetic fibers having a fineness of normal staple fibers may be further contained.

In the method for producing a lightweight felt material according to the present invention, a nonwoven sheet is placed on a running conveyor followed by a first web entangled with microfine fibers, hollow fibers and low melting point fibers, and further, a microfine fiber, a hollow fiber, The second web to be entangled is placed to form a three-layer laminate, and then the three-layer laminate is simultaneously subjected to heat treatment and pressurization at a temperature exceeding the melting point of the low melting point fiber to attain the simultaneous felting and integration . In this production method, it is preferable to more firmly bond the nonwoven sheet and the first and second webs by fluffing up both surfaces of the nonwoven sheet by embossing treatment at low temperature or brushing the surface.

The lightweight felt material according to the present invention is a composite material of a specular surface layer and a nonwoven sheet, and is superior in sound absorption properties and flame retardancy even when compared with conventional melt blown nonwoven fabrics, and is relatively inexpensive. The lightweight felt material of the present invention has flexibility and is easy to fit on the inner surface of a vehicle, and can be used not only as an interior material for an automobile or a vehicle, but also for industrial materials such as soundproof thermal insulation materials, It is also applicable to clothing materials.

The lightweight felt material according to the present invention has a balance of thickness, weight and density with a basis weight, a thickness and a density equal to those of a conventional meltblown nonwoven fabric, a sound absorbing performance and a flame retardancy suitable for FMVSS302. The lightweight felt of the present invention can be advantageously used as a substitute for a conventional meltblown nonwoven fabric by appropriately adjusting sound-absorbing performance and flame-retardant performance since it is advantageous in terms of cost since no adhesive material or the like is required at the time of production.

The method for producing a lightweight felt material according to the present invention is a method in which a first web, a non-woven sheet and a second web are laminated and heat-treated to be unified, so that a lightweight felt material can be produced in one line. By using the production method of the present invention, it is possible to efficiently produce a lightweight felt material and to reduce the manufacturing cost. Further, if the both surfaces of the nonwoven sheet are previously floated, the peel strength of the entire felt material can be increased.

1 is an enlarged cross-sectional view showing a lightweight felt material according to the present invention.
2 is an enlarged cross-sectional view showing a modification of the lightweight felt material.
3 is a schematic side view illustrating a manufacturing process of a lightweight felt material.
4 is a partial perspective view showing the three-layered laminate in a disassembled state.
5 is a graph showing the sound absorption ratios of the felt materials of the second and third embodiments and the comparative examples A to C;
Fig. 6 is a graph showing sound absorption ratios of the felt material and the comparison D of Examples 5 and 6; Fig.

As shown in Fig. 1, the lightweight felt material 1 according to the present invention is integrated by interposing a nonwoven sheet 5 between two mirror-surface layers 2 and 3. The mirror-surface layers 2 and 3 are usually of the same thickness, density and basis weight distribution, and the sound-absorbing performance of the felt material 1 may be further improved by appropriately adjusting the thickness and the like of the two according to the desire. When the felt material (1) is used as an interior material, a skin material having a desirable appearance, feel, nap sensation or the like is further adhered by ordinary temperature or heat treatment.

The lightweight felt material 1 may have a three-layer structure generally as shown and the mirror surface layer itself may have a plurality of layers. In addition, the lightweight felt material 1 may be formed by arranging two nonwoven sheets in each of three layers of the specular surface layers, or three nonwoven sheets in each of the four specular layers, In order to increase the adhesive strength of the specular surface layer, it is also possible to spray the adhesive powder in an amount sufficient to prevent the sound absorbing performance from being deteriorated, and to apply the adhesive liquid therebetween.

The mirror-surface layers 2 and 3 may be formed by entanglement of 20 to 80% of microfine fibers, 10 to 60% of hollow fibers and 10 to 60% of low melting point fibers, and synthetic fibers of normal fineness may be appropriately added. The mirror-surface layers 2 and 3 generally have the same fiber composition, but they can be changed in accordance with the use of the felt material 1. Fig. Polyester, acrylic, polyamide, rayon, polypropylene, polyvinyl chloride, polyethylene, etc. may be used for the microfine fibers, the hollow fibers and the synthetic fibers of usually fineness. In terms of cost and heat resistance, it is preferable that any of polyester fiber, hollow fiber, low melting point fiber and synthetic fiber of normal fineness be polyester.

In the specular surfaces 2 and 3, microfine fibers mean fibers having a fineness of 1.1 dtex (1 denier) or less, which is difficult to be ordinarily radiated. In the present invention, microfine fibers and ultrafine fibers are also included. The melt blowing method, the centrifugal spinning method, the flash spinning method, the beating method, the mixed spinning method, the tag spinning method and the like are used for producing the monofilament microfibers. The added amount of the microfine fibers is 20 to 80% by weight, preferably 40 to 80% by weight, which is a relatively large amount. If the addition amount of the microfine fibers is less than 20%, it is difficult to increase the sound absorbing performance of the felt material 1. On the other hand, if it exceeds 80%, it is difficult to make the felt material 1 large in volume and is also economical.

In the specular surface layers 2 and 3, the hollow fiber is a kind of heterogeneous cross-section fibers, and for example, a special spinning nozzle is used for melt spinning of polyester, acrylic, polyamide or the like In the case of rayon spinning, bubbles may be generated inside the fibers to form a hollow sectioned yarn. This hollow fiber is strong in appearance, has a large fineness, has a strong crimp, generally has good warmth and lightness, and strengthens the elasticity of the felt. The amount of the hollow fibers to be added is 10 to 60% by weight, preferably 10 to 30% by weight, which can impart balmability. When the hollow fiber is added in an amount of less than 10%, it is difficult to impart the elastic property to the felt material 1. On the other hand, if the hollow fiber exceeds 60%, the flexibility of the felt material 1 is impaired.

In the specular surfaces 2 and 3, the low melting point fibers have a melting point of about 40 to 70 DEG C lower than that of the microfine fibers, the hollow fibers and the synthetic fibers of normal fineness, ). ≪ / RTI > Examples of the low melting point fibers include low melting point polyesters, low melting point polyamides, polyethylene, and polypropylene, and may be copolymers with ethylene or butene. The low-melting-point fiber may be a known fiber or a resin filament having a melting point of 90 to 170 캜 or a mixed fiber thereof if the melting point is lower than that of ordinary fibers, and a composite fiber such as a parallel or sheath core structure is also preferable. The amount of the low melting point fibers to be added is 10 to 60% by weight, preferably 20 to 50% by weight, in which the whole is easily integrated. If the content of the low melting point fibers is less than 10%, it is difficult to integrate the felt material 1 with the heat treatment or adhere to the nonwoven sheet 5 by heat treatment, while if it exceeds 60%, the felt material 1 becomes too hard as a whole.

When the low melting point fiber is a sheath core structure polyester fiber, the sheathing fiber may be a low melting point polyester having a melting point of 110 deg. C, 130 deg. C, 150 deg. C or 160 deg. C, The fibers of the core are regular polyesters having a melting point of 250 캜. In the case of sheath core PP / PE fibers, the sheathing fibers are polyethylene having a melting point of 130 to 134 占 폚, and the fibers of the core are polypropylene having a melting point of 165 占 폚. The sheath core structure PP / PE fiber has a smaller binder effect and less repulsive property than the sheath core structure polyester fiber, even though the PP / PE fiber can be used at a relatively low cost.

In the specular surfaces 2 and 3, in addition to the above-mentioned respective fibers, it may further contain 10 to 30% of staple fibers of synthetic fibers having various finenesses or various yarns (recovered regenerated surfaces) And the addition amount is within a range in which the sound absorption performance is not deteriorated. From the viewpoint of cost, the lightweight felt material 1 can be produced at a very low cost because it is advantageous to put a flattened hatch.

In the lightweight felt material (1), the upper specular layer (2) and the lower specular layer (3) are generally the same in thickness and density. In addition, as in the lightweight felt material 6 shown in Fig. 2, it is possible to change the thickness ratio to 1: 4, preferably 1: 2.2 for the mirror-surface layers 2 and 3 in order to further improve the sound- And the sound absorption performance is hardly improved even if the ratio of the thickness is made larger. When the thickness of the specular surface layer 2 differs from that of the specular surface layer 3, it is necessary to arrange the specular surface layer 2 so that sound is incident from the thinner specular surface layer 2. For example, when sound is incident from the thicker specular surface layer 3 side, The sound absorbing performance of the ash 1 is lowered.

In the upper specular surface layer 2, the thickness is preferably 10 to 19 mm and the basis weight is preferably 100 to 300 g / m 2, and the preferable thickness is about 12 mm and the basis weight is about 177 g / m 2. On the other hand, the lower specular surface layer 3 preferably has a thickness of 19 to 30 mm and a basis weight of 100 to 300 g / m 2, and a preferable specimen is a thickness of about 25 mm and a basis weight of about 123 g / m 2.

The nonwoven sheet 5 is preferably composed of microfine fibers having a fiber diameter of from 2 to 20 mu m, and the nonwoven sheet can be produced by each of the above-mentioned methods, preferably by the meltblown method. The meltblown nonwoven sheet 5 is low density, bulky, and drape-rich and flexible. A plurality of short fibers adjacent to each other in the web are gathered with respect to the meltblown nonwoven sheet 5 to form a connection portion in which at least a part of the fibers in the longitudinal direction of the web is adhered to each other. For example, in a meltblown nonwoven sheet, a kneaded resin is extruded from a nozzle onto a conveyor while blowing out hot air, and the ultra-fine fibers are entangled with heat to form a sheet. In the meltblown nonwoven sheet, it is preferable that the connecting fibers including the connecting portion are bonded at the intersections of the fibers constituting the meltblown web.

The nonwoven fabric sheet 5 is preferably a relatively thin, drapable nonwoven fabric having a thickness of 0.1 to 1.0 mm and preferably has a basis weight of 20 to 100 g / m 2, The basis weight is about 40 g / m 2. If the basis weight of the nonwoven sheet 5 is less than 30 g / m 2, the sound absorbing performance of the felt material 1 can not be sufficiently increased. On the other hand, when the basis weight of the nonwoven sheet 5 exceeds 100 g / m 2, the improvement in sound absorption performance is small and the flexibility tends to deteriorate.

The microfine fibers constituting the nonwoven sheet 5 are made of polyester, acrylic, polyamide, polypropylene, polyethylene, polyvinyl chloride or the like, and are preferably polyester in view of cost and heat resistance. The microfine fibers may be sprayed after the formation of the sheet or immersed in a solution of the flame retardant agent. This flame retardancy can be similarly applied to the specular surfaces 2, 3 as well.

In order to continuously produce the lightweight felt material 1, the felt manufacturing apparatus 7 of the combination arrangement schematically illustrated in Fig. 3 may be used. The conveyor 8 generally 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. In the first and second card cross wrappers 10 and 12 adjacent to each other, an accumulated layer is formed by mixing superfine fibers, hollow fibers, and low melting point fibers with a known card unit, and the stacked layers are stacked in a cross- (See Fig. 4).

The long non-woven sheet 5 is horizontally disposed between the card cloth wrappers 10 and 12, and is discharged from the winding roll onto the conveyor 8. On the other hand, the long non-woven sheet 5 can be fed from the outside of the apparatus via a plurality of rollers 20. [ Both sides of the non-woven sheet 5 can be adhered more reliably to the non-woven sheet and the first and second webs if they are pre-folded by embossing at low temperature or brushing the surface beforehand.

The heat treatment machine 22 is provided at the rear of the second card cross wrapper 12 and the second web 16, the nonwoven sheet 5 and the first web 14) (see Fig. 4) is uniformly heated on the conveyor 8. The three- This heating temperature needs to exceed the melting point of the low melting point fibers in the webs 14 and 16, thereby melting the low melting point fibers. A pair of pressure rollers 26 and a cooler 28 are additionally provided in the rear of the heat treatment device 22 in sequence. 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, the first card cloth wrapper 10 is first entangled with ultrafine fibers, hollow fibers and low melting point fibers, and the first web 14 corresponding to the lower specular surface layer 3 On the conveyor (8). Subsequently, on the conveyor 8, a long nonwoven sheet 5 is successively placed on the first web 14. The second card cross wrapper 12 entraps a predetermined amount of ultrafine fibers, hollow fibers and low melting point fibers and the second web 16 corresponding to the upper specular layer 2 on the conveyor 8 And is continuously placed on the nonwoven sheet 5 to form a three-layer laminate 24.

The three-layered laminate 24 (see FIG. 4) having passed through the second card cross wrapper 12 is uniformly heated on the conveyor 8 in the heat treatment apparatus 22, and is further heated by a pair of pressure rollers 26 to simultaneously achieve the entire felting and the integration, and the lightweight felt material 1 is continuously produced. The lightweight felt material 1 thus obtained is cooled by cold air falling in the cooler by passing through the cooler 28. [

The obtained lightweight felt material 1 is preferably 8 to 50 mm in thickness and 300 to 500 g / m 2 in basis weight, and a preferable thickness is about 38 mm and a basis weight of about 340 g / m 2. In a specific use, the thickness can be up to about 100 mm, the basis weight can be about 3000 g / m 2, the density can be 0.005 g / cm 3, and the upper limit can be 0.043 g / cm 3 or more.

As an example of a general specification of the lightweight felt material (1), the density is 0.025 g / cm 3 when the thickness is 8 mm and the basis weight is 340 g / m 2. A thickness of 10 mm, a density of 0.0340 g / cm3, a thickness of 15 mm, a density of 0.0227 g / cm3, a thickness of 20 mm, a density of 0.0170 g / cm3, a thickness of 25 mm and a density of 0.0136 g / Cm3, a thickness of 30 mm, a density of 0.0113 g / cm3, a thickness of 35 mm, a density of 0.0097 g / cm3, a thickness of 40 mm and a density of 0.0085 g / cm3. It has a basis weight of 580 g / m 2, a thickness of 60 mm, a basis weight of 510 g / m 2, a thickness of 70 mm, a basis weight of 595 g / M < 2 >, the density becomes 0.0085 g / cm < 3 >.

Example 1

Next, the present invention will be described based on examples, but the present invention is not limited to the examples. In order to produce the lightweight felt material 1 shown in Fig. 1, 40% of ultrafine polyester fibers with a fineness of 0.75 denier and 15% by weight of hollow polyester fibers with a fineness of 15 denier were prepared by using the felt manufacturing apparatus 7 shown in Fig. , 25% of low melting point polyester fibers having a fineness of 4 denier and 20% of 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 meltblown sheet having a basis weight of 40 g / m 2 (trade name: Graflex BTS0040EM, manufactured by Kuraray Co., Ltd.) is used.

A nonwoven sheet (5) is placed between the webs (14, 16) and the whole is heat bonded. The obtained lightweight felt material (1) has the nonwoven sheet (5) positioned at the center of the felt material, and the thickness and the basis weight distribution of the upper and lower specular layers (2, 3) are equal. The lightweight felt 1 has a thickness of 38 mm and a basis weight of 340 g / m 2.

Example 2

A lightweight felt material (1) having the same fiber composition as in Example 1 was prepared using a polyester tumbler in place of the polyester single strand having a fineness of 3 denier in Example 1 by using a tester. In this lightweight felt material 1, the upper specular surface layer 2 has a thickness of 19 mm and a basis weight of 155 g / m 2 while the lower specular surface layer 3 has a thickness of 19 mm and a basis weight of 155 g / to be.

The obtained lightweight felt material (1) had a thickness of 38 mm and a basis weight of 350 g / m 2. Considering the cost, 20% of the polyester monofilaments can be added instead of the polyester staple fibers.

Example 3

Using the felt manufacturing apparatus 7 shown in Fig. 3, the webs 14 and 16 are of the same fiber composition as the first embodiment, and the nonwoven sheets 5, which are the same as those of the first embodiment, And the whole is heated and adhered to produce a lightweight felt material 1. The obtained lightweight felt material (1) had a thickness of 38 mm and a basis weight of 407 g / m 2.

The lightweight felt material (1) of Example 2 and Example 3 is compared with the following products.

Comparative A: meltblown nonwoven fabric having a thickness of 38 mm (trade name: Shinhwa TC3303 300)

         (Basis weight 356 g / ㎡)

Comparative B: meltblown nonwoven fabric having a thickness of 38 mm (trade name: ShinShirt Regular 300)

Comparative C: Felt material in which the nonwoven sheet 5 does not intervene in the same fiber composition as in Example 3

         (Thickness 38 mm and basis weight 386 g / m 2)

The lightweight felt material (1) of Examples 2 and 3 and Comparative Examples A to C all have a thickness of 38 mm. Sound absorption data by the vertical incidence method was measured for these products, and the results are shown in Table 1 below.

5 shows the results of Table 1 in a graph. From this graph, it is clear that the lightweight felt material 1 of Examples 2 and 3 has a sound absorption ratio equal to or higher than that of Comparative A and B which are known meltblown nonwoven fabrics (trade name: Synthetic). From the sound absorption ratio of the comparison C, the nonwoven sheet 5 is essential in the lightweight felt material of the present invention.

Example 4

Using the felt manufacturing apparatus 7 shown in Fig. 3, the webs 14 and 16 are of the same fiber composition as the first embodiment, and the nonwoven sheets 5, which are the same as those of the first embodiment, And the whole is heated and adhered to produce a lightweight felt material 6 (Fig. 2). In the lightweight felt material 6, the upper specular surface layer 2 has a thickness of 12 mm and a basis weight of 202 g / m 2 while the lower specular surface layer 3 has a thickness of 26 mm and a basis weight of 165 g / .

The lightweight felt material 6 having different thicknesses of the mirror-surface layers 2 and 3 has a different basis weight distribution and a total weight of about 50 g / m 2. However, the lightweight felt material 1 The sound absorption performance is greatly increased.

Example 5

The lightweight felt material (1) is produced in the same manner as in Example 1. The obtained lightweight felt material (1) had a thickness of 20 mm and a basis weight of 327 g / m 2.

Example 6

A lightweight felt material (1) is produced by the same fiber blending as in Example 2. The obtained lightweight felt material (1) had a thickness of 20 mm and a basis weight of 333 g / m 2.

The lightweight felt material (1) of Example 5 and Example 6 is compared with the following products.

Comparative D: meltblown nonwoven fabric having a thickness of 20 mm (trade name: ShinShil TC3303 300)

        (Basis weight 326 g / ㎡)

The lightweight felt materials (1) and D of Example 5 and Example 6 were all 20 mm thick. Sound absorption data by the vertical incidence method was measured for these products, and the results are shown in Table 2 below.

6 shows the results of Table 2 in a graph. It is clear from this graph that the lightweight felt material 1 of Examples 5 and 6 has a sound absorption ratio equal to or higher than that of Comparative D which is a known meltblown nonwoven fabric (trade name: Synthetic) even at a thickness of 20 mm.

1: lightweight felt material
2: upper specular layer
3: Lower specular layer
5: Non-woven sheet

Claims (7)

A lightweight felt material comprising a pair of mirror-surface layers sandwiched between two mirror-surface layers interposed between the mirror-surface layers, wherein both of the mirror-surface layers comprise 20-80% of microfine fibers having a fineness of 1.1 decitex or less, 10-60% And 10 to 60% of low-melting-point fibers to be melted at the time of the whole heat treatment are blended, and the nonwoven sheet has a fiber diameter of 2 to 20 占 퐉 and a basis weight of 20 to 100 g / m2. A lightweight felt material having a large volume that thermally compresses and integrates the entire body by interposing a non-woven sheet between two specular surfaces of the two specular layers. In both specular surfaces, 20 to 80% of microfine fibers having a fineness of 1.1 decitex or less, 10 to 30% of hollow fibers and 10 to 60% of low melting point fibers to be melted at the time of heat treatment as a whole are blended, and the nonwoven sheet has an average fiber diameter of 2 to 20 占 퐉 and a basis weight of 20 to 100 g / Lightweight felt material such as. 3. The method according to claim 1 or 2,
Wherein the ratio of the thickness of the upper specular layer to the thickness of the lower specular layer is 1: 1 to 1: 4. 3. The method according to claim 1 or 2,
Wherein the nonwoven sheet is a nonwoven fabric produced by a meltblown method. 3. The method according to claim 1 or 2,
The light-weight felt material according to any one of claims 1 to 3, further comprising 10 to 30% of short fiber or half-finished yarn of synthetic fibers of normal fineness in the specular surface layer. A nonwoven sheet was placed on the running conveyor following the first web entangled with the microfine fibers, the hollow fibers and the low melting point fibers, and the second web entangled with the microfine fibers, the hollow fibers and the low melting point fibers was placed on the conveyor. Layer laminate, and subsequently, the three-layer laminate is simultaneously subjected to heat treatment and pressing at a temperature exceeding the melting point of the low-melting-point fiber to attain simultaneous felting and integration. The method according to claim 6,
The nonwoven sheet is bonded to the first and second webs more reliably by embossing both surfaces of the nonwoven sheet by embossing treatment at low temperature or by brushing the surface.

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