Felt and soundproofing material

Abstract

To provide a felt from which a soundproofing material excellent in sound-absorbing performance, and having a light-weight and a large thickness, can be produced, the felt being excellent in shape followability when formed, a production method of the felt, and the soundproofing material formed from the felt.SOLUTION: A felt contains 1 to 15 mass% of a heat-expandable organic ballon, and has a surface weight of more than 400 g / m2 and 1200 g / m2 or less. The production method of the felt and the soundproofing material are also provided.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a felt, a method for manufacturing a felt, and a soundproofing material. [Background technology]

[0002] Noise in automobiles is reduced by installing various soundproofing materials in the engine compartment, dash, ceiling, floor, trunk, etc. Soundproofing materials are also used in construction materials other than automobiles, such as floors, walls, and ceilings. Soundproofing materials are required to have improved sound absorption performance as well as reduced weight (reduced bulk density). For example, Patent Document 1 discloses a method for producing a nonwoven fabric for soundproofing, which comprises impregnating a nonwoven fabric substrate, which is obtained by blending and thermally bonding nonwoven fabric substrate fibers with fibers having a lower melting point than the nonwoven fabric substrate fibers, with a coating liquid containing thermally expandable particles, expanding the thermally expandable particles to a thickness of 5 mm or more, and reducing the content of the thermally expandable particles after expansion to 20 g / m 2 The following method is described: [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-33675 Summary of the Invention [Problem to be solved by the invention]

[0004] The manufacturing method described in Patent Document 1 can produce a nonwoven fabric for soundproofing with a low bulk density by expanding thermally expandable microparticles, but because the nonwoven fabric substrate obtained by needle-punching a cross-laminated fiber web is impregnated with a coating liquid containing thermally expandable microparticles, it is difficult to increase the thickness of the nonwoven fabric for soundproofing. Therefore, in order to form it into a thick shape, the basis weight of the nonwoven fabric for soundproofing must be increased, making it difficult to reduce its weight. Furthermore, soundproofing materials are manufactured by pressing felt to fit the shape of the part where it is to be used. However, in areas where the felt is pulled during molding, such as curved surfaces, the fibers become sparse, impairing the sound-absorbing performance and appearance, so there is a demand for improvements in shape-following ability during molding.

[0005] The object of the present invention is to produce a light-weight, thick soundproofing material with excellent sound absorption performance, The present invention also provides a felt that is excellent in shape-following ability during molding, a method for manufacturing the felt, and a soundproofing material obtained by molding the felt. [Means for solving the problem]

[0006] The present inventors have found that the above problems can be solved by the following configuration.

[0007] (1) Contains 1 to 15% by mass of thermally expandable organic balloons and has a surface weight of 400 g / m 2 Exceeding 1200g / m 2 Below is the felt. (2) The felt according to (1), wherein the diameter of the thermally expandable organic balloon before expansion is 5 to 50 μm. (3) This is a method for producing felt by mixing thermally expandable organic balloons with fibers before subjecting the mixture to a fiber-opening roller in the air-laying method, a dry molding method for nonwoven fabrics. (4) A soundproofing material obtained by molding the felt according to (1) or (2) into a thickness of 2 to 120 mm by heat and pressure molding. [Effects of the Invention]

[0008] According to the present invention, it is possible to manufacture a light-weight, thick soundproof material having excellent sound absorption performance, Furthermore, it is possible to provide a felt that has excellent shape-following properties during molding, a method for producing the felt, and a soundproofing material obtained by molding the felt. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a graph showing the results of measurement of the sound absorption coefficient of the felt of Example 1 using a reverberation chamber method. [Figure 2] 1 is a cross-sectional photograph of a soundproofing material molded using the felt of Example 1. [Figure 3] 1 is a cross-sectional photograph of a soundproofing material molded using the felt of Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described below. Each configuration and combination thereof in the following embodiments is an example, and the present invention is not limited to the embodiments. In this specification, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0011] [felt] The felt of the present invention contains 1 to 15 mass % of thermally expandable organic balloons and has a surface weight of 400 g / m 2 Exceeding 1200g / m 2 The following is the result.

[0012] The felt of the present invention can be used to manufacture soundproofing materials. The felt of the present invention has excellent shape conformability during molding. This is thought to be because the felt of the present invention contains thermally expandable organic balloons, which expand when heated during press molding, and the fibers do not become sparse even in parts of the felt that are pulled during molding, such as curved surfaces.

[0013] The surface weight of the felt of the present invention is 400 g / m 2 Exceeding 1200g / m 2 is as follows: 500~1000g / m 2 It is preferable that the thickness is 600 to 800 g / m 2 It is more preferable that:

[0014] The thickness of the felt of the present invention is not particularly limited, but is preferably 5 to 60 mm. It is more preferably 10 to 50 mm, and even more preferably 15 to 40 mm.

[0015] <Thermal-expandable organic balloon> The felt of the present invention contains 1 to 15 mass % of thermally expandable organic balloons relative to the total mass of the felt. The thermally expandable organic balloons contained in the felt of the present invention are in a state before being expanded by heating, and are typically present dispersed among the fibers in the felt. The type of thermally expandable organic balloon that can be used in the present invention is not particularly limited, but it is preferable that the thermally expandable organic balloon be a thermally expandable microcapsule formed by encapsulating a volatile organic solvent (e.g., hydrocarbon, ether, halogenated hydrocarbon, etc.) in a thermoplastic resin (e.g., copolymers of acrylonitrile, vinylidene chloride, (meth)acrylic acid ester, etc.).

[0016] The thermally expandable organic balloon preferably expands in volume by 5 to 15 times when heated, More preferably, the volume expands by 7 to 13 times, and even more preferably, the volume expands by 8 to 12 times. The temperature at which the thermally expandable organic balloons expand is not particularly limited, but is preferably 140 to 220°C, and more preferably 160 to 200°C.

[0017] The diameter of the thermally expandable organic balloon before expansion is preferably 5 to 50 μm, more preferably 15 to 40 μm.

[0018] The felt of the present invention preferably contains 2 to 15 mass %, more preferably 3 to 10 mass %, and even more preferably 4 to 8 mass % of thermally expandable organic balloons relative to the total mass of the felt.

[0019] <Fiber> The felt of the present invention typically contains fibers. The type of fiber is not particularly limited, and for example, natural fibers, chemical fibers, etc. can be used. Examples of natural fibers include cotton, silk, hemp, wool, jute, etc. Examples of chemical fibers include polyester fibers, polyamide fibers, acrylic fibers, polyolefin fibers, glass fibers, acetate fibers, rayon, recycled wool, etc.

[0020] The fibers used in the felt of the present invention are preferably short fibers, and the fiber length is preferably 10 to 64 mm, more preferably 20 to 40 mm.

[0021] The felt of the present invention preferably contains fibers in an amount of 50 to 90 mass %, more preferably 65 to 85 mass %, based on the total mass of the felt.

[0022] <Binder> The felt of the present invention preferably contains a binder. The binder has the function of bonding the fibers together. The type of binder is not particularly limited, but preferred are thermosetting resins such as phenolic resin, epoxy resin, urethane resin, silicone resin, xylene resin, and unsaturated polyester resin, and thermoplastic resins such as polyester, polypropylene, polyethylene, and polyamide. By heating these thermosetting resins and thermoplastic resins, a binder is formed, which can bond the fibers together. The thermosetting resin for forming the binder is preferably in the form of powder. The thermoplastic resin for forming the binder is preferably in the form of fiber or powder. The fiber of the thermoplastic resin is The thermoplastic resin fiber may have a core-sheath structure. Examples of the thermoplastic resin fiber having a core-sheath structure include a fiber having a core made of a normal polyester and a sheath made of a low-melting point polyester.

[0023] When the felt of the present invention contains a binder, the content of the binder is preferably 5 to 40% by mass, more preferably 15 to 30% by mass, based on the total mass of the felt.

[0024] <Other ingredients> The felt of the present invention may contain other components in addition to the components described above. Other components include, for example, miscellaneous wool (recycled old clothing), fiber waste, urethane chip waste, crushed nonwoven fabric waste, flame retardants, fillers (calcium carbonate, etc.), and the like. When the felt of the present invention contains the above-mentioned other components, the content of the above-mentioned other components is: The content of the porous material is preferably 5 to 90% by mass, more preferably 40 to 80% by mass, based on the total mass of the felt.

[0025] The felt of the present invention is preferably a single layer felt. The felt of the present invention is preferably a felt that can be combined with a nonwoven fabric having a design or other function. Examples of the nonwoven fabric include a needle-punched nonwoven fabric, a spunlace nonwoven fabric, a melt-blown nonwoven fabric, and a spunbond nonwoven fabric.

[0026] [Felt manufacturing method] The method for producing the felt of the present invention is preferably an air-laying method, which is a dry molding method for nonwoven fabric, in which thermally expandable organic balloons and fibers are mixed together before being subjected to a defibrating roller.

[0027] The above manufacturing method employs the air-laying method, which is a dry molding method for nonwoven fabrics, and since the thermally expandable organic balloons and fibers are mixed in a dry state, a thick felt can be manufactured. In addition, before being subjected to the fiber-opening roller of the air-laying method (for example, immediately before the fiber-opening roller), By adding the thermally expandable organic balloons, the thermally expandable organic balloons can be uniformly mixed into the fibers without adding a step of mixing the fibers with the thermally expandable organic balloons. The fiber-opening roller is a roller that defibrates the fibers supplied to the air-laying machine and carries them to a zone where they are dispersed by the air flow. Furthermore, in the above-mentioned manufacturing method, the felt can be manufactured by mixing the thermally expandable organic balloons with the fibers, and then heating and forming the mixture into a sheet. This eliminates the need for the steps of impregnating the fibers with a coating solution containing the thermally expandable organic balloons and squeezing them, resulting in excellent production efficiency and reduced powder shedding. There is also little risk of the thermally expandable organic balloon falling off. Furthermore, in the above manufacturing method, the thermally expandable organic balloons are mixed in during the fiber-opening process, so the thermally expandable organic balloons are dispersed more uniformly throughout the layer than in a method in which the felt is first manufactured and then impregnated with a wet method. The thermally expandable organic balloons and fibers can be those described above. When mixing the thermally expandable organic balloons with the fibers, it is preferable to further mix the above-mentioned thermosetting resin or thermoplastic resin for forming the binder.

[0028] When the thermally expandable organic balloons and fibers are mixed together, the other components described above may be further mixed therewith.

[0029] The mixing ratio of each component used in the production of the felt is preferably adjusted so that the content of each component in the felt falls within the above-mentioned range.

[0030] [Soundproofing material] The soundproofing material of the present invention is preferably obtained by hot-press molding the above-mentioned felt of the present invention. During hot-press molding, it is preferable that the thermally expandable organic balloons expand, so that the fibers do not become sparse even in parts where the felt is pulled during molding, such as curved surfaces. The thickness of the soundproof material of the present invention is not particularly limited, but is preferably 2 to 120 mm, more preferably 15 to 100 mm, and even more preferably 20 to 80 mm.

[0031] The surface weight of the soundproofing material of the present invention is 400 g / m, which is the same as the above-mentioned felt. 2 Exceeding 1200g / m 2 Preferably, the density is 500 to 1000 g / m or less. 2 More preferably, it is 600 to 800 g / m 2It is more preferable that: [Example]

[0032] The present invention will be described in more detail below with reference to the following examples. The materials, amounts used, proportions, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention.

[0033] [1] Manufacturing method Example 1 Felt was produced by air-laying using 18% by mass of 9 μm diameter glass fiber, 53% by mass of disassembled old clothing, 23% by mass of powdered phenolic resin, and 6% by mass of thermally expandable organic balloons. The surface weight of the felt was 800 g / m 2 It was. Next, this felt is molded and heated in a mold heated to 180°C to a thickness of 20 mm and a surface weight of 800 g / m 2 We manufactured soundproofing material (molded felt).

[0034] <Comparative Example 1> A felt and a soundproofing material were produced in the same manner as in Example 1, except that no thermally expandable organic balloons were used. The surface weight of the felt in Comparative Example 1 was 1200 g / m 2 Also, The soundproofing material of Comparative Example 1 has a thickness of 20 mm and a surface weight of 1200 g / m 2 It was.

[0035] <Comparative Example 2> Felt and soundproofing materials were produced in the same manner as in Example 1, except that no thermally expandable organic balloons were used and the surface weight was adjusted to be the same as in Example 1. The surface weight of the felt in Comparative Example 2 was 800 g / m 2 The thickness of the soundproofing material of Comparative Example 2 was 20 mm, and the surface weight was 800 g / m 2 It was.

[0036] [2] Evaluation of physical properties Test pieces were cut out from the soundproofing material manufactured in [1] above, and the test pieces were used to measure (1) the air permeability, (2) Sound absorption performance and (3) three-point bending load were measured. In addition, (4) shape conformability during molding was evaluated from the cross-sectional photographs of the felt when it was molded in a mold in [1] above.

[0037] (1) Airflow volume (airflow resistance) The airflow resistance was measured according to ISO9053. The air permeability of the soundproofing material of Example 1 is 19744 Ns / m 4 It was. The air permeability of the soundproofing material of Comparative Example 1 is 18956 Ns / m 4 It was. From the above, it was found that Example 1 was lighter than Comparative Example 1 and had the same amount of air permeability.

[0038] (2) Sound absorption performance The results of the measurement of sound absorption coefficient in a reverberation room, which was performed in accordance with JIS A1409:1998, the measurement method for sound absorption coefficient in a reverberation room, are shown in Figure 1. The horizontal axis of Figure 1 is frequency (Hz), and the vertical axis is sound absorption coefficient. In FIG. 1, ● indicates the results of Example 1, ◯ indicates the results of Comparative Example 1, and Δ indicates the results of Comparative Example 2. As shown in Figure 1, it was found that the sound absorption performance of the soundproofing material of Example 1 was excellent. It was found that the soundproofing material of Example 1 was lighter than the soundproofing material of Comparative Example 1, and also had the same or better soundproofing effect in terms of acoustic performance.

[0039] (3) Three-point bending load The three-point bending load was measured with reference to JIS K 7171. As a result, the maximum point load was 6.0 N in Example 1. The maximum point load in Comparative Example 1 was 7.1 N, and it is presumed that the soundproofing material of Example 1 has sufficient rigidity.

[0040] (4) Shape conformability during molding Figure 2 shows a cross-sectional photograph of a soundproofing material molded using the felt of Example 1. Figure 3 shows a cross-sectional photograph of a soundproofing material molded using the felt of Comparative Example 1. The parts shown in Figures 2 and 3 are parts at corresponding positions. 2 and 3, it can be seen that the curvature of the curved surface is greater than that of the felt of Example 1 in Fig. 2, even though the surface weight of the felt of Comparative Example 1 is lower than that of the felt of Comparative Example 1. In other words, the felt of Example 1 conforms to the shape of the mold with right-angled corners better than the felt of Comparative Example 1 (the area of ​​the region formed by the surfaces of the corners of the mold and the curved surface of the felt is smaller in Example 1 than in Comparative Example 1). Therefore, it was found that the felt of Example 1 was lighter in weight and had higher shape conformability during molding than the felt of Comparative Example 1.

Claims

1. A thermally expandable organic balloon containing 1 to 15 mass % and a surface weight of 400 g / m ２ Exceeding 1200 g / m ２ Below is the felt.

2. 2. The felt according to claim 1, wherein the diameter of the thermally expandable organic balloon before expansion is 5 to 50 μm.

3. This is a method for producing felt by mixing thermally expandable organic balloons with fibers before subjecting the mixture to a fiber-opening roller in the air-laying method, a dry molding method for nonwoven fabrics.

4. A soundproofing material obtained by molding the felt according to claim 1 or 2 into a thickness of 2 to 120 mm by heat and pressure molding.

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