JP2007223273A - Sound absorbing material - Google Patents
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本発明は、植物由来原料を用いることにより大気中のＣＯ２濃度増加の抑制、石油可採年数の延長や、マテリアルリサイクル、サマーリサイクル、バイオリサイクルなどのリサイクルが可能な環境に優しい、しかも吸音性と曲げ強度とに優れた吸音材に関するものである。本発明の吸音材は、従来、吸音材として使用不可能であった、曲げ強度が必要とされる例えば建築材料や自動車内装材分野における最表層材や内面材などの幅広い分野で用いられるものである。 The present invention is an environment-friendly and sound-absorbing material that can suppress the increase in CO 2 concentration in the atmosphere by using plant-derived materials, extend the number of years that oil can be collected, and can recycle materials recycling, summer recycling, biorecycling, etc. And a sound-absorbing material excellent in bending strength. The sound-absorbing material of the present invention is conventionally used as a sound-absorbing material and is used in a wide range of fields such as the outermost layer material and inner surface material in the field of building materials and automobile interior materials that require bending strength. is there.
従来から、建築材料などに使用される吸音材としては、例えば鉱物由来のアスベスト、ガラス繊維からなるグラスウール等の無機繊維が多く用いられてきた。また、自動車内装材には、石油由来の不織布や発泡体などが吸音材として使用されてきた。 Conventionally, inorganic fibers such as asbestos derived from minerals and glass wool made of glass fibers have been used as sound absorbing materials used for building materials. In addition, petroleum-derived non-woven fabrics and foams have been used as sound absorbing materials for automobile interior materials.
しかしながら、前述の無機繊維は、鉱物やガラスの極細繊維が用いられていることから、現在、作業環境の汚染、作業者、使用者への健康障害、さらには廃棄処理の困難性が問題となっている。また、前述の不織布や発泡体は石油由来原料であるため、環境への負荷が少なくないなどの問題があった。さらには、例えば建築材料や自動車内装材用途の吸音材に要求される強度としては、施工性や搬送性、また使用時の耐久性を考慮すると、その曲げ強度はおおよそ８０〜８０００Ｎ／ｃｍ２程度のものがほしいところであるが、これらの不織布や発泡体は曲げ強度が低く、吸音材の用途が限定されていた。 However, since the inorganic fibers described above are made of mineral or glass ultrafine fibers, there are problems of contamination of the work environment, health problems for workers and users, and difficulty of disposal. ing. Moreover, since the above-mentioned nonwoven fabric and foam are petroleum-derived raw materials, there have been problems such as not only a small burden on the environment. Furthermore, for example, the strength required for sound absorbing materials for building materials and automobile interior materials is approximately 80 to 8000 N / cm 2 when considering workability, transportability, and durability during use. However, these non-woven fabrics and foams have low bending strength, and the use of the sound absorbing material is limited.
このような従来技術の問題点に対して、近年では天然繊維にバインダとして植物由来のポリ乳酸が混在した繊維系ボードが提案されている（特許文献１参照）。しかしながら、このボードは天然繊維とポリ乳酸を使用しているため、環境負荷が少ないという効果を有するものの、この文献で規定されている見かけ密度が０．２ｇ／ｃｍ３以上という範囲では優れた吸音性は得られない。このように、繊維系ボードのみでは優れた吸音性は得られない。 In recent years, a fiber-based board in which plant-derived polylactic acid is mixed as a binder with natural fibers has been proposed in order to solve such problems of the prior art (see Patent Document 1). However, since this board uses natural fiber and polylactic acid, it has the effect of reducing the environmental load, but it has excellent sound absorption in the range where the apparent density specified in this document is 0.2 g / cm 3 or more. Sex cannot be obtained. Thus, excellent sound absorption cannot be obtained only with the fiber board.
また、植物繊維を熱可塑性樹脂で結着した成形体が提案されている（特許文献２参照）。しかしながら、この成形体の結着材は熱可塑性樹脂であるものの、この文献で規定されている熱可塑性樹脂はポリオレフィン、ポリエステル、ポリアミドなどの石油系であることから、環境への負荷が少なくないという問題があった。また、このような成形体のみでは優れた吸音性は得られない。 Moreover, the molded object which bound the vegetable fiber with the thermoplastic resin is proposed (refer patent document 2). However, although the binder of this molded body is a thermoplastic resin, the thermoplastic resin specified in this document is petroleum-based, such as polyolefin, polyester, polyamide, etc., so there is not much impact on the environment. There was a problem. In addition, excellent sound absorption cannot be obtained only with such a molded body.
また、特許文献３には、天然繊維と生分解性繊維とからなる生分解性樹脂成形体が示されている。これは、成形体中の繊維間空間に開口性の膜を膜形成剤により形成し、この膜に通気抵抗を付与して吸音効果を高めたものである。この文献によると、低・中周波数域である２ｋＨｚ以下の吸音効果が改善されてはいるが、２ｋＨｚで吸音効果が約０．７５では低・中周波数域の優れた吸音材とは言えない。 Patent Document 3 discloses a biodegradable resin molded body composed of natural fibers and biodegradable fibers. In this method, an opening film is formed with a film forming agent in the inter-fiber space in the molded body, and a ventilation resistance is imparted to the film to enhance the sound absorbing effect. According to this document, although the sound absorption effect of 2 kHz or less which is a low / medium frequency region is improved, if the sound absorption effect is about 0.75 at 2 kHz, it cannot be said that the sound absorption material is excellent in the low / medium frequency region.
一方、有機繊維の不織布の表面に、通気量が０．０１〜３０ｍＬ／ｃｍ2・ｓｅｃの紙が積層された吸音材（特許文献４参照）や、有機繊維からなる不織布の表面に通気量が０．０１〜１０ｍＬ／ｃｍ2・ｓｅｃの紙が積層された吸音材（特許文献５参照）が開示されている。しかしながら、これら不織布は、いずれも有機繊維であるポリエステルやアラミド繊維などの石油系繊維を使用していることから、環境への負荷が少なくないという問題があった。さらに、これら不織布は曲げ強度が低いことから、それ自体が強度を有する補強材に貼り付けるという使用方法のみであり、吸音材としての用途が限定されていた。
本発明の目的は、かかる従来技術の欠点に鑑み、植物由来原料を用いることにより環境への負荷を低減できるとともに、例えば建築材料や自動車内装材などの、今まで吸音材としては強度が低いがために使用不可能であった、強度が必要とされる最表層材や内面材などの幅広い用途で用いられる吸音材を提供することにある。 The object of the present invention is to reduce the burden on the environment by using plant-derived raw materials in view of the disadvantages of the prior art, and has low strength as a sound-absorbing material such as building materials and automobile interior materials. Therefore, the object is to provide a sound-absorbing material that can be used for a wide range of applications such as an outermost layer material and an inner surface material that require strength.
本発明は、かかる課題を解決するために、次の手段を採用する。
（１）平均繊維長が５〜１００ｍｍの範囲内の天然繊維にバインダとしてポリ乳酸系樹脂が混在し、かつ、見かけ密度が０．２〜０．６ｇ／ｃｍ３の範囲内である繊維系ボードの表面に、通気度が０．０１〜５ｍＬ／ｃｍ2・ｓｅｃの範囲内のシート状物を貼り付けたことを特徴とする吸音材。
（２）ＪＩＳ Ａ ５９０５（２００３）に基づいて測定された曲げ強さが８０〜８０００Ｎ／ｃｍ２の範囲内である前記（１）に記載の吸音材。
（３）前記繊維系ボードと、シート状物との接着面積比率が３５％以下である前記（１）又は（２）に記載の吸音材。
（４）前記シート状物が紙である前記（１）〜（３）のいずれかに記載の吸音材。
（５）前記紙が木質パルプ紙である前記（１）〜（４）のいずれかに記載の吸音材。
（６）天然由来原料を全重量に対して９５重量％以上含む前記（１）〜（５）のいずれかに記載の吸音材。
（７）前記（１）〜（６）のいずれかに記載の吸音材を用いた建築材料又は自動車内装材。
The present invention employs the following means in order to solve such problems.
(1) A fiber-based board in which a polylactic acid resin is mixed as a binder with natural fibers having an average fiber length of 5 to 100 mm and an apparent density is in a range of 0.2 to 0.6 g / cm 3. A sound-absorbing material, characterized in that a sheet-like material having an air permeability of 0.01 to 5 mL / cm 2 · sec is attached to the surface.
(2) The sound absorbing material according to (1), wherein the bending strength measured based on JIS A 5905 (2003) is in the range of 80 to 8000 N / cm 2 .
(3) The sound absorbing material according to (1) or (2), wherein a bonding area ratio between the fiber board and the sheet-like material is 35% or less.
(4) The sound absorbing material according to any one of (1) to (3), wherein the sheet-like material is paper.
(5) The sound absorbing material according to any one of (1) to (4), wherein the paper is wood pulp paper.
(6) The sound-absorbing material according to any one of (1) to (5), which includes 95% by weight or more of a naturally-derived material.
(7) A building material or automobile interior material using the sound absorbing material according to any one of (1) to (6).
本発明の吸音材によれば、平均繊維長が５〜１００ｍｍの範囲内の天然繊維にバインダとしてポリ乳酸系樹脂が混在し、かつ、見かけ密度が０．２〜０．６ｇ／ｃｍ３の範囲内である繊維系ボードの表面に、通気度が０．０１〜５ｍＬ／ｃｍ2・ｓｅｃの範囲内のシート状物を貼り付けたので、環境への負荷が低減できるとともに、曲げ強度と吸音性が向上し、今まで吸音材として使用不可能であった曲げ強度が必要とされる例えば建築材料や自動車内装材分野の最表層材や内面材などの幅広い用途で用いることができる。 According to the sound-absorbing material of the present invention, polylactic acid-based resin is mixed as a binder with natural fibers having an average fiber length in the range of 5 to 100 mm, and the apparent density is in the range of 0.2 to 0.6 g / cm 3 . Since a sheet-like material having an air permeability of 0.01 to 5 mL / cm 2 · sec is pasted on the surface of the fiberboard, the load on the environment can be reduced, and the bending strength and sound absorption For example, it can be used in a wide range of applications such as the outermost layer material and inner surface material in the field of building materials and automobile interior materials, which require bending strength that could not be used as a sound absorbing material.
以下、本発明を実施するための最良の形態について説明する。 Hereinafter, the best mode for carrying out the present invention will be described.
本発明の吸音材は、前述したとおり、平均繊維長が５〜１００ｍｍの範囲内の天然繊維にバインダとしてポリ乳酸系樹脂が混在し、かつ、見かけ密度が０．２〜０．６ｇ／ｃｍ３の範囲内にある繊維系ボードの表面に、通気度が０．０１〜５ｃｃ／ｃｍ２／ｓｅｃの範囲内のシート状物を貼り付けたことに特徴を有する。前述したように、生分解性繊維で構成される繊維ボードの見かけ密度や通気度を限定し、これに通気性のあるシート状物を積層した吸音材は、従来技術に散見されるが、本発明者らは、これらの条件を全て同時に満足させるとともに、特に強度を高める工夫をしたことにより、環境への負荷を低減できることは勿論、曲げ強度と吸音性に優れた建築材料及び自動車内装材用途の吸音材が得られることを見出した。 As described above, the sound-absorbing material of the present invention includes a natural fiber having an average fiber length of 5 to 100 mm mixed with a polylactic acid resin as a binder and an apparent density of 0.2 to 0.6 g / cm 3. It is characterized in that a sheet-like material having an air permeability in the range of 0.01 to 5 cc / cm 2 / sec is attached to the surface of the fiber board in the range of. As described above, sound absorbing materials in which the apparent density and air permeability of a fiber board made of biodegradable fibers are limited and laminated with air-permeable sheet-like materials are often found in the prior art. The inventors satisfy all of these conditions at the same time, and, in particular, by improving the strength, the load on the environment can be reduced, as well as building materials and automobile interior materials excellent in bending strength and sound absorption. It has been found that a sound absorbing material can be obtained.
本発明の吸音材を構成する繊維系ボードは、石油由来原料の使用比率を低減させ環境負荷を低減する観点から、天然繊維を用いることが必要である。よって、従来の石油を原料としたポリエステル短繊維やナイロン短繊維は、前記の観点より好ましくない。 The fiber-based board constituting the sound absorbing material of the present invention needs to use natural fibers from the viewpoint of reducing the usage ratio of petroleum-derived raw materials and reducing the environmental load. Therefore, conventional polyester short fibers and nylon short fibers made from petroleum are not preferred from the above viewpoint.
天然繊維としては、その中でもセルロース系繊維であることが好ましい。例えば、木質系や草本系のセルロース系繊維である。そして、強度の高い保温材を得るには、できるだけ繊維長の長いセルロース系繊維を用いることが好ましい。そのような繊維としては、具体的には、木材パルプ、バガス、ムギワラ、アシ、パピルス、タケ類等のイネ科植物、パルプ、木綿、ケナフ、ローゼル、アサ、アマ、ラミー、ジュート、ヘンプ、まお等の靭皮繊維、サイザルアサおよびマニラアサ等の葉脈繊維等であり、これらを単独で用いても良いがこれらの中から選ばれる１種以上の繊維が含まれていることが好ましい。これらのうちでも、比較的繊維長が長く、一年草であって熱帯地方及び温帯地方での成長が極めて早く容易に栽培できる草本類に属するケナフあるいはジュートから採取される繊維を採用すると、曲げ強度に優れた吸音材を得ることができる。特に、ケナフの靭皮にはセルロースが６０％以上と高い含有率で存在しており、かつ高い強度を有していることから、ケナフ靭皮から採取されるケナフ繊維を用いることが好ましい。 Among these natural fibers, cellulosic fibers are preferred. For example, woody and herbaceous cellulosic fibers. And in order to obtain a heat insulating material with high intensity | strength, it is preferable to use the cellulose fiber as long as possible. Specific examples of such fibers include wood pulp, bagasse, wheat straw, reeds, papyrus, bamboo and other grasses, pulp, cotton, kenaf, roselle, Asa, flax, ramie, jute, hemp, mao Bast fibers such as sisal as well as Manila Asa, and these may be used alone, but it is preferable that one or more fibers selected from these are included. Among these, if fibers are collected from kenaf or jute belonging to herbs that are relatively long in fiber length, are annual grasses, and grow very quickly and easily in the tropics and temperate regions, A sound-absorbing material having excellent strength can be obtained. In particular, it is preferable to use kenaf fibers collected from kenaf bast because kenaf bast contains cellulose at a high content of 60% or more and has high strength.
本発明では上記天然繊維は、その平均繊維長が５〜１００ｍｍの範囲内であることが必要である。これら一定の繊維長の、すなわち短繊維の天然繊維で繊維系ボードを構成することにより、優れた強度の繊維系ボードを得ることが可能となる。本発明者らは、短繊維の繊維長を５ｍｍ以上とすることにより、曲げ強度は勿論、吸音材施工時の施工性や搬送性、また使用時の耐久性をも満足するに必要な強度を有する繊維系ボードが得られることを見出した。短繊維長が５ｍｍを下回ると上記用途において必要とされる強度を得ることができない。一方、短繊維長が１００ｍｍを超えると、繊維系ボードの製造において、短繊維とポリ乳酸樹脂とを均一に分散させることが困難となり、生産性が低下すると共に強度が不均一となり、部分的に強度が低下する恐れがある。強度を発現させるためのより好ましい天然繊維の平均繊維長は、２０〜１００ｍｍ、最も好ましい範囲は５０〜１００ｍｍである。 In the present invention, the natural fiber needs to have an average fiber length in the range of 5 to 100 mm. By configuring the fiber board with natural fibers having a certain fiber length, that is, short fibers, it is possible to obtain a fiber board with excellent strength. By making the fiber length of the short fibers 5 mm or more, the present inventors have the strength necessary to satisfy not only the bending strength but also the workability and transportability during construction of the sound absorbing material and the durability during use. It has been found that a fiber-based board is obtained. If the short fiber length is less than 5 mm, the strength required in the above application cannot be obtained. On the other hand, when the short fiber length exceeds 100 mm, it becomes difficult to uniformly disperse the short fibers and the polylactic acid resin in the production of the fiber-based board, and the productivity is lowered and the strength is not uniform. Strength may be reduced. The average fiber length of the more preferable natural fiber for expressing the strength is 20 to 100 mm, and the most preferable range is 50 to 100 mm.
ここで、施工時の搬送性、使用時の耐久性を満足するに必要な曲げ強度とは、ＪＩＳ Ａ ５９０５：２００３に準拠して測定される曲げ強さにおいて、８０〜８０００Ｎ／ｍ２の範囲内のものを指す。より好ましい曲げ強度は、１００〜８０００Ｎ／ｍ２、最も好ましい範囲は５００〜８０００Ｎ／ｍ２である。 Here, the bending strength required to satisfy the transportability during construction and the durability during use is a range of 80 to 8000 N / m 2 in bending strength measured according to JIS A 5905: 2003. It points to the inside. A more preferable bending strength is 100 to 8000 N / m 2 , and a most preferable range is 500 to 8000 N / m 2 .
また、本発明では上記の短繊維を結合されるためのバインダ（結合剤）として、ポリ乳酸樹脂を用いる必要がある。ポリ乳酸樹脂を用いると強度に優れた繊維系ボードを得ることができると同時に、石油系原料の使用比率を低下させ、環境負荷を低減できるからである。ポリ乳酸樹脂は、非石油系原料、すなわちトウモロコシなどの植物を原料とするものであり、製造工程においても石油系の溶剤をほとんど使用しないために、繊維系ボードの製造、使用および廃棄の階段を全体で考えたとき、環境への負荷を少なくすることができるものである。また、ポリ乳酸樹脂は、生分解性プラスチックの中でも強度が高く、融点が１７０℃程度と適度な耐熱性を有すると共に、成形性に優れ、他の天然繊維や木質系材料との接着性も優れている。 Moreover, in this invention, it is necessary to use a polylactic acid resin as a binder (binder) for couple | bonding said short fiber. This is because when a polylactic acid resin is used, a fiber-based board having excellent strength can be obtained, and at the same time, the use ratio of petroleum-based raw materials can be reduced, and the environmental load can be reduced. Polylactic acid resin is made from non-petroleum-based raw materials, that is, plants such as corn, and uses almost no petroleum-based solvent in the manufacturing process. When considered as a whole, the load on the environment can be reduced. In addition, polylactic acid resin has high strength among biodegradable plastics, has a melting point of about 170 ° C. and moderate heat resistance, is excellent in moldability, and has excellent adhesion to other natural fibers and wood-based materials. ing.
ポリ乳酸樹脂としては、ポリ乳酸ホモポリマーの他、乳酸コポリマーおよびブレンドポリマー等の乳酸系ポリマーが含まれている。乳酸系ポリマーの重量平均分子量は、一般に５〜５０万である。また、ポリ乳酸樹脂におけるＬ−乳酸単位とＤ−乳酸単位の構成モル比Ｌ／Ｄは、１００／０〜０／１００のいずれであっても良いが、高い融点を得るにはＬ乳酸あるいはＤ乳酸のいずれかの単位を９０モル％以上含むことが好ましい。 The polylactic acid resin includes a lactic acid-based polymer such as a lactic acid copolymer and a blend polymer in addition to a polylactic acid homopolymer. The weight average molecular weight of the lactic acid polymer is generally 5 to 500,000. In addition, the constituent molar ratio L / D of the L-lactic acid unit to the D-lactic acid unit in the polylactic acid resin may be any of 100/0 to 0/100. However, in order to obtain a high melting point, L-lactic acid or D It is preferable to contain 90 mol% or more of any unit of lactic acid.
また、ポリ乳酸樹脂には、カルボジイミド化合物を添加することが好ましい。乳酸系ポリマーまたはこれに含まれるオリゴマーの反応活性末端を不活性化し、ポリ乳酸系樹脂の加水分解を抑制するものである。従って、高温や高湿環境下で使用された場合に劣化しにくい繊維系ボードを得るために好適なポリ乳酸樹脂を得ることが可能となる。ここで言うカルボジイミド化合物としては、例えば、ジイソシアネート化合物を重合したものが好適に用いられるが、中でも４，４−ジシクロヘキシルメタンカルボジイミドの重合体やテトラメチルキシリレンカルボジイミドの重合体やその末端をポリエチレングリコールなどで封鎖したカルボジイミド化合物が好ましく用いられる。 Moreover, it is preferable to add a carbodiimide compound to the polylactic acid resin. The reaction active terminal of the lactic acid polymer or the oligomer contained therein is inactivated to suppress hydrolysis of the polylactic acid resin. Therefore, it is possible to obtain a polylactic acid resin suitable for obtaining a fiber-based board that hardly deteriorates when used in a high temperature or high humidity environment. As the carbodiimide compound, for example, a polymer obtained by polymerizing a diisocyanate compound is preferably used. Among them, a polymer of 4,4-dicyclohexylmethane carbodiimide, a polymer of tetramethylxylylene carbodiimide, or a terminal thereof is polyethylene glycol or the like. A carbodiimide compound blocked with is preferably used.
また、ポリ乳酸樹脂の全重量に対して０．１〜２０重量％の結晶核剤を含有させることにより、結合剤であるポリ乳酸の結晶核の形成を促進させ、繊維系ボードの曲げ強度を向上することができる。結晶核剤としては、一般にポリマーの結晶核剤として用いられるものを用いることができ、本発明で使用する結晶核剤としては、ポリ乳酸樹脂中に均一に分散し効率良く結晶核を形成できる点で特にタルクが好ましい。タルクの平均粒径としては好ましくは分散性の点から０．５〜７μｍであり、例えば燃焼時の損失分を除いた成分中のＳｉＯ２とＭｇＯの割合が９３重量％以上であるタルクを挙げることができる。本発明で使用する結晶核剤は、１種のみでもよくまた２種以上の併用を行ってもよい。 In addition, by containing 0.1 to 20% by weight of a crystal nucleating agent with respect to the total weight of the polylactic acid resin, the formation of crystal nuclei of polylactic acid as a binder is promoted, and the bending strength of the fiber-based board is increased. Can be improved. As the crystal nucleating agent, those generally used as a polymer crystal nucleating agent can be used, and the crystal nucleating agent used in the present invention can be uniformly dispersed in a polylactic acid resin to efficiently form crystal nuclei. In particular, talc is preferable. The average particle size of talc is preferably 0.5 to 7 μm from the viewpoint of dispersibility, and examples include talc in which the ratio of SiO 2 and MgO in the component excluding the loss during combustion is 93% by weight or more. be able to. The crystal nucleating agent used in the present invention may be used alone or in combination of two or more.
前述のとおり、繊維系ボードは、植物由来のポリ乳酸樹脂や、好ましくはセルロース系繊維などの天然繊維を含むものであるが、環境負荷低減の観点から、前記の天然由来原料を繊維系ボード全重量に対して９５重量％以上含むことが好ましく、植物由来原料のみからなる繊維系ボードであることがより好ましい。 As described above, the fiber-based board includes plant-derived polylactic acid resin, and preferably natural fibers such as cellulosic fibers. From the viewpoint of reducing the environmental burden, the above-mentioned naturally-derived raw material is added to the total weight of the fiber-based board. On the other hand, it is preferable to contain 95% by weight or more, and it is more preferable that the fiber board is composed only of plant-derived materials.
かくして成る繊維系ボードは、その見かけ密度が０．２〜０．６ｇ／ｃｍ３の範囲内であることが、目標とする吸音性を得るために必要である。見かけ密度を０．６ｇ／ｃｍ３以下にすることで多孔質性のボードが形成され、音波が孔を通り抜ける際に孔壁付近で空気の乱流が発生する。この乱流が音波を摩擦エネルギーに変化させることで吸音作用が行われ、吸音材として必要な吸音率が得られ、かつ、軽量な繊維系ボードを得ることが可能となる。一方、見かけ密度が０．６ｇ／ｃｍ３を上回るとボード内部の空隙が少なくなり必要とする吸音率が得られなくなり、また、軽量性が失われるために好ましくない。また、見かけ密度が０．２ｇ／ｃｍ３を下回ると強度が失われるため好ましくない。 The fiber board thus formed needs to have an apparent density in the range of 0.2 to 0.6 g / cm 3 in order to obtain a target sound absorbing property. When the apparent density is 0.6 g / cm 3 or less, a porous board is formed, and turbulence of air is generated in the vicinity of the hole wall when sound waves pass through the hole. This turbulent flow changes sound waves into frictional energy, so that a sound absorbing action is performed, a sound absorption coefficient required as a sound absorbing material is obtained, and a lightweight fiber board can be obtained. On the other hand, if the apparent density exceeds 0.6 g / cm 3 , the gap inside the board is reduced and the required sound absorption coefficient cannot be obtained, and the lightness is lost. Moreover, since an intensity | strength will be lost when an apparent density is less than 0.2 g / cm < 3 >, it is unpreferable.
繊維系ボードは、少なくとも片面にシート状物が例えば熱可塑性樹脂、熱硬化性樹脂等の接着剤で一体に貼り合わせられて本発明の吸音材を構成する。 The fiber-based board constitutes the sound-absorbing material of the present invention by integrally bonding a sheet-like material on at least one surface with an adhesive such as a thermoplastic resin or a thermosetting resin.
シート状物としては、例えば、紙、フィルム、布帛等が好ましく、いずれのものでもよいがその通気度は０．０１〜５ｍＬ／ｃｍ2・ｓｅｃの範囲内であることが必要である。ボード表面にシート状物を貼り付けることにより、シート状物が音波により振動する。この際に通気孔内で音波を振動エネルギーに変化させることで吸音作用が行われ、前述の繊維系ボード自体の吸音作用と相まって、吸音材全体として優れた吸音性が得られる。 As the sheet-like material, for example, paper, film, fabric and the like are preferable, and any of them may be used, but the air permeability needs to be within a range of 0.01 to 5 mL / cm 2 · sec. By attaching the sheet-like material to the board surface, the sheet-like material is vibrated by sound waves. At this time, a sound absorbing action is performed by changing sound waves into vibration energy in the vent hole, and in combination with the sound absorbing action of the above-described fiber board itself, an excellent sound absorbing property as the whole sound absorbing material is obtained.
更に優れた吸音性を得る場合には、繊維ボードとシート状物層間での接着面積比率を３５％以下にすることで、音波によるシート状物の振動面積を増加させることができ、これにより吸音性能が向上し、厳しい吸音性が要求される建築材料、自動車内装材用吸音材などに適用することが可能となる。 In order to obtain more excellent sound absorption, the vibration area of the sheet can be increased by the acoustic wave by setting the bonding area ratio between the fiber board and the sheet to 35% or less. The performance is improved, and it becomes possible to apply to building materials that require strict sound absorbing properties, sound absorbing materials for automobile interior materials, and the like.
本発明の吸音材の厚さは、厳しい吸音性が要求される建築材料、自動車内装材用吸音材などに適用する場合、１０ｍｍ以上であることが好ましい。 The thickness of the sound-absorbing material of the present invention is preferably 10 mm or more when applied to building materials that require strict sound-absorbing properties, sound-absorbing materials for automobile interior materials, and the like.
次に、本発明の吸音材を得るための好ましい製造方法を説明する。 Next, a preferable manufacturing method for obtaining the sound absorbing material of the present invention will be described.
まず、公知のカット方法で得たポリ乳酸からなる平均繊維長が２０〜１００ｍｍ程度の短繊維と、平均繊維長が５〜１００ｍｍの範囲内の天然繊維とを準備する。これら両繊維を混合比率が１０：９０〜６０：４０の範囲内になるように取り分け、オープナー、ローラーカード、ニードルパンチングマシン、などの装置により混綿、開繊及び繊維間を絡合させて布状の不織布を得る。この工程でポリ乳酸樹脂を短繊維状として混綿、開繊しているので、ポリ乳酸樹脂と天然繊維とを均一に分散させることができ、均一な吸音孔が形成される。 First, short fibers having an average fiber length of about 20 to 100 mm made of polylactic acid obtained by a known cutting method and natural fibers having an average fiber length in the range of 5 to 100 mm are prepared. These fibers are separated so that the mixing ratio is within the range of 10:90 to 60:40, and mixed cotton, fiber opening, and fibers are intertwined by a device such as an opener, a roller card, a needle punching machine, or the like to form a cloth. A non-woven fabric is obtained. In this step, since the polylactic acid resin is blended and opened as a short fiber, the polylactic acid resin and the natural fiber can be uniformly dispersed, and uniform sound absorbing holes are formed.
混合して得られた布状物を、表面温度が１７０〜２２０℃に加熱された熱板で挟んだ後、圧力が０．５〜１０ＭＰa程度になるように圧縮するか、またはこれら加熱と圧縮を同時に行うことで板状のボードに成形する。この際、布状物は適当なスペーサを介して１〜１５０段程度の複数段にしたうえで纏めて過熱及び圧縮を同時に行い、これら条件を適宜操作することにより前述の見かけ密度、曲げ強度及び厚みを有する繊維系ボードを得る。しかし、圧力が０．５〜１０ＭＰａ程度の圧縮時の加熱温度が１７０℃未満では、ポリ乳酸繊維が溶融せずボード全体にバインダが行きわたらない。また、加熱温度が２２０℃以上ではボードに焦げが発生し、天然繊維の強度が落ちることから、施工性や搬送性、また使用時の耐久性に必要な強度が得られない可能性がある。 The cloth-like material obtained by mixing is sandwiched between hot plates heated to a surface temperature of 170 to 220 ° C. and then compressed so that the pressure is about 0.5 to 10 MPa, or these heating and compression are performed. Are simultaneously formed into a plate-like board. At this time, the cloth-like material is made into a plurality of stages of about 1 to 150 stages through appropriate spacers, and then superheated and compressed simultaneously, and by appropriately operating these conditions, the above-mentioned apparent density, bending strength and A fibrous board having a thickness is obtained. However, when the heating temperature during compression at a pressure of about 0.5 to 10 MPa is less than 170 ° C., the polylactic acid fiber does not melt and the binder does not reach the entire board. Further, when the heating temperature is 220 ° C. or higher, the board is burnt and the strength of the natural fiber is lowered, so that there is a possibility that the strength required for workability, transportability, and durability during use may not be obtained.
次にこの繊維系ボードの表面に、シート状物を接着剤で接着する。接着剤としては例えば熱可塑性樹脂、熱硬化性樹脂などを用い、以下の接着方法により接着する。 Next, a sheet-like material is bonded to the surface of the fiber board with an adhesive. As the adhesive, for example, a thermoplastic resin, a thermosetting resin or the like is used, and adhesion is performed by the following adhesion method.
例えば、繊維系ボード成形後、ボード表面に樹脂溶液を等間隔に置き、シート状物を接着面積比率３５％以下となるように貼り付けるのである。また、接着面積比率を低下させるために樹脂溶液をボードの端部のみに置き、シート状物を貼り付けることもできる。この場合、前記樹脂溶液はポリ乳酸樹脂であることが好ましい。一方、ボードの表面にシート状物を置き、その上から接着面積比率３５％以下となるように等間隔に加熱溶融した接着樹脂を塗布し、冷却によって固化させるというホットメルト接着法でもよい。さらには、接着面積比率を抑えるためにボードの端部のみをホットメルト接着法により接着させてもよい。また、生産性を高めたい場合には、前記ポリ乳酸短繊維と天然繊維との布状物、又は前記布状物の積層体の表裏面、あるいは表面か裏面のいずれかにシート状物を積層し、加熱した後圧縮するが、加熱と圧縮を同時に行うことにより、布状物中のポリ乳酸を溶融させ、シート状物を貼り付けても良い。 For example, after forming the fiber-based board, the resin solution is placed on the board surface at equal intervals, and the sheet-like material is pasted so that the adhesion area ratio is 35% or less. Moreover, in order to reduce the bonding area ratio, the resin solution can be placed only on the edge of the board and a sheet-like material can be attached. In this case, the resin solution is preferably a polylactic acid resin. On the other hand, a hot melt bonding method may be used in which a sheet-like material is placed on the surface of the board, and an adhesive resin that is heated and melted at equal intervals so as to have a bonding area ratio of 35% or less is applied and solidified by cooling. Furthermore, in order to suppress the bonding area ratio, only the end portion of the board may be bonded by a hot melt bonding method. When it is desired to increase productivity, a sheet-like material is laminated on the cloth-like material of the polylactic acid short fiber and natural fiber, or on the front and back surfaces of the laminate of the cloth-like material, or on the front surface or the back surface. Then, after heating, compression is performed. However, by performing heating and compression simultaneously, the polylactic acid in the cloth-like material may be melted and the sheet-like material may be attached.
なお、シート状物の通気度は、厚さを操作することにより０．０１〜５ｍＬ／ｃｍ2・ｓｅｃの範囲内に調整できる。以上により、本発明の吸音材が得られる。 The air permeability of the sheet-like material can be adjusted within the range of 0.01 to 5 mL / cm 2 · sec by manipulating the thickness. Thus, the sound absorbing material of the present invention is obtained.
本発明の吸音材は、曲げ強度が低いがために今まで吸音材として使用不可能であった、例えば建築材料及び自動車内装材分野などの曲げ強度が必要とされる最表層材や内面材などに好適に用いることができる。 The sound-absorbing material of the present invention has been unusable as a sound-absorbing material until now because of its low bending strength, for example, the outermost layer material and inner surface material that require bending strength in the fields of building materials and automobile interior materials, etc. Can be suitably used.
以上、実施例によって本発明の吸音材について、更に詳細に説明するが、これらは本発明を限定するものではない。 As mentioned above, although the sound-absorbing material of the present invention will be described in more detail by way of examples, these do not limit the present invention.
［測定方法］
（１）平均繊維長
ＪＩＳ Ａ １０１５：１９９９ ８．４．１に準じて測定した。
試料を８００ｍｇ量り取り、ステープルダイヤグラムを作成し、図記したステープルダイヤグラムを５０の繊維長群に等分し、各区分の境界及び両端の繊維長を測定し、両端繊維長の平均に４９の境界繊維長を加えて５０で除し、平均繊維長（ｍｍ）を算出し、２回の平均値をとった。
[Measuring method]
(1) Average fiber length It measured according to JIS A 1015: 1999 8.4.1.
Weigh 800 mg of sample, create a staple diagram, divide the illustrated staple diagram into 50 fiber length groups, measure the boundary of each segment and the fiber length at both ends, and find 49 boundaries at the average fiber length at both ends The fiber length was added and divided by 50, the average fiber length (mm) was calculated, and the average value was taken twice.
（２）見かけ密度
ＪＩＳ Ａ ５９０５：２００３ ６．３に準じて測定した。
繊維系ボードを温度２０℃、湿度６５％ＲＨの標準状態にて２４ｈｒ放置後、１０ｃｍ×１０ｃｍの試験片を３枚切り出した。
１枚の試験片について、上記規定中図５に示す測定箇所の幅、長さ及び厚さを測定し、それぞれについての平均値を求め試験片の幅、長さ及び厚さとし、体積（ｖ）を求めた。次に、質量（ｍ）を測定し、次式によって算出した。厚さは０．０５ｍｍ、幅及び長さは０．１ｍｍ、質量は０．１ｇの精度まで測定し、密度は０．０１ｇ／ｃｍ３単位まで算出した。
１枚の試験片ごとに密度を求めた上で、３枚の試験片の平均値を求めた。
密度（ｇ／ｃｍ３）＝ｍ／ｖ
ここに、ｍ：質量（ｇ）
ｖ：体積（ｃｍ３）。
(2) Apparent density It was measured according to JIS A 5905: 2003 6.3.
The fiber board was left to stand for 24 hours in a standard state of a temperature of 20 ° C. and a humidity of 65% RH, and three 10 cm × 10 cm test pieces were cut out.
For one test piece, the width, length, and thickness of the measurement points shown in FIG. 5 are measured in the above definition, and the average value for each is obtained to obtain the width, length, and thickness of the test piece. Volume (v) Asked. Next, mass (m) was measured and calculated by the following formula. The thickness was measured to 0.05 mm, the width and length were 0.1 mm, the mass was measured to an accuracy of 0.1 g, and the density was calculated to 0.01 g / cm 3 units.
After obtaining the density for each test piece, the average value of the three test pieces was obtained.
Density (g / cm 3 ) = m / v
Where m: mass (g)
v: Volume (cm 3 ).
（３）曲げ強さ
ＪＩＳ Ａ ５９０５：２００３ ６．６に準じて測定した。繊維系ボードから、縦方向および横方向のそれぞれについて、幅５０ｍｍ、長さ１５０ｍｍの試験片を３枚ずつ採取した。上記規定に準じた曲げ強さ試験装置（支点及び荷重作用点の曲率半径はそれぞれ５．０ｍｍ）に、スパン（Ｌ）１００ｍｍとして試験片を設置し、スパンの中間位置にて試験片の表面から平均変形速度５０ｍｍ／分の荷重を加え、その最大荷重（Ｐ）を測定し、次式によって曲げ強さを求め、６枚の平均値を算出した。
曲げ強さ(ＭＰａ)＝３ＰＬ／２ｂｔ２
ここに、Ｐ：最大荷重（Ｎ）
Ｌ：スパン（ｍｍ）
ｂ：試験片の幅（ｍｍ）
ｔ：試験片の厚さ（ｍｍ）。
(3) Bending strength Measured according to JIS A 5905: 2003 6.6. Three test pieces each having a width of 50 mm and a length of 150 mm were collected from the fiber board in each of the longitudinal direction and the transverse direction. A test piece is installed as a span (L) of 100 mm in a bending strength test apparatus (the radii of curvature of the fulcrum and load application point are 5.0 mm each) in accordance with the above regulations, and from the surface of the test piece at an intermediate position of the span. An average deformation speed of 50 mm / min was applied, the maximum load (P) was measured, the bending strength was determined by the following formula, and the average value of 6 sheets was calculated.
Bending strength (MPa) = 3PL / 2bt 2
Where P: Maximum load (N)
L: Span (mm)
b: Width of test piece (mm)
t: thickness of the test piece (mm).
（４）通気量
ＪＩＳ Ｌ １０９６−１９９９ ８.２７．１ Ａ法（フラジール形法）に準じて測定した。試料の異なる５か所から約２０ｃｍ×２０ｃｍの試験片を採取し、フラジール形試験機を用い、円筒の一端（吸気側）に試験片を取り付けた。試験片の取り付けに際し、円筒の上に試験片を置き、試験片上から吸気部分を塞がないように均等に約９８Ｎ（１０ｋｇｆ）の荷重を加え試験片の取り付け部におけるエアーの漏れを防止した。試験片を取り付けた後、加減抵抗器によって傾斜形気圧計が１２５Ｐａの圧力を示すように吸込みファンを調整し、そのときの垂直形気圧計の示す圧力と、使用した空気孔の種類とから、試験機に付属の表によって試験片を通過する空気量を求め、５枚の試験片についての平均値を算出した。
(4) Aeration rate Measured according to JIS L 1096-1999 8.27.1 Method A (Fragile Form Method). Test pieces of about 20 cm × 20 cm were collected from five different locations of the samples, and the test pieces were attached to one end (intake side) of the cylinder using a Frazier type tester. When attaching the test piece, the test piece was placed on the cylinder, and a load of about 98 N (10 kgf) was applied evenly from above the test piece so as not to block the intake portion, thereby preventing air leakage at the test piece attachment portion. After attaching the test piece, the suction fan was adjusted so that the inclination type barometer showed a pressure of 125 Pa by an adjusting resistor, and from the pressure indicated by the vertical type barometer and the type of air hole used, The amount of air passing through the test piece was obtained from a table attached to the test machine, and the average value for the five test pieces was calculated.
（５）吸音材の吸音率
ＪＩＳ Ａ １４０５：１９９８に拠って垂直入射吸音率を測定した。
試料から直径９０ｍｍの円形の試験片を３枚採取した。
試験装置としては、電子測器株式会社製の自動垂直入射吸音率測定器（型式１００４１A）を用いた。この試験装置におけるインピーダンス管は、外径１０１．６ｍｍ、内径９１．６ｍｍ、全長２１６０ｍｍであった。
試験片を、インピーダンス管の一端に金属反射板との間に空気層がないように設置した。そして、１００〜２０００Ｈｚの周波数域の音波を段階的に試験片に垂直に入射させ、その周波数の平面波について入射音響パワーに対して試験体表面に入る（戻ってこない）音響パワーの比を測定し、３枚の試験片についての平均値を算出した。
(5) Sound Absorption Rate of Sound Absorbing Material The normal incident sound absorption rate was measured according to JIS A 1405: 1998.
Three circular test pieces having a diameter of 90 mm were collected from the sample.
As a test apparatus, an automatic normal incidence sound absorption measuring device (model 10041A) manufactured by Denki Sokki Co., Ltd. was used. The impedance tube in this test apparatus had an outer diameter of 101.6 mm, an inner diameter of 91.6 mm, and a total length of 2160 mm.
The test piece was placed at one end of the impedance tube so that there was no air layer between it and the metal reflector. Then, a sound wave having a frequency range of 100 to 2000 Hz is incident on the test piece in a stepwise manner, and a ratio of the acoustic power that enters (does not return to) the surface of the specimen with respect to the incident acoustic power is measured with respect to the plane wave of that frequency. The average value about three test pieces was calculated.
（６）接着面積比率
前記吸音率測定に用いた紙積層繊維系ボードとシート状物との接着面積比率を次の方法で求めた。
(6) Adhesion area ratio The adhesion area ratio between the paper laminated fiber board used for the sound absorption measurement and the sheet-like material was determined by the following method.
シート状物として紙を積層した吸音材から紙を全て剥離した後、前記紙に付着した接着剤より、ｍｍ単位の透明な方眼フィルムを用いて接着面積を測定した。まず、透明なフィルムに１ｍｍの距離を置いて直角に交わる縦線と横線を引き、多数の１ｍｍ２角の正方形が描いた透明な方眼フィルムを作成した。線の太さは０．２８ｍｍとした。次に前記方眼フィルムを前記シート状物に当て、接着部分の１ｍｍ２角正方形の数を測定し、正方形の合計より接着面積を算定した。この場合、１ｍｍ２に満たない接着剤部分は接着していないものとみなした。なお、シート状物に接着剤が付着しない場合は、シート状物を剥離した後の繊維系ボード表面より前記方眼シートを用いて同様の方法で求める。また、繊維系ボード表面とシート状物とにそれぞれ接着剤が残った場合は、繊維系ボード及びシート状物の両方より前期方眼シートを用いて同様の方法で接着面積を求める。以上より、接着面積比率を下記の式より求めた。
接着面積比率（％）＝接着面積（ｍ２）／繊維系ボードの全表面積（ｍ２）×１００。
After all the paper was peeled from the sound-absorbing material in which the paper was laminated as a sheet-like material, the adhesive area was measured using a transparent grid film in mm units from the adhesive attached to the paper. First, draw a vertical and horizontal lines intersecting at right angles at a distance of 1mm to transparent film to create a transparent grid film squares depicting the number of 1mm 2 square. The thickness of the line was 0.28 mm. Then against the grid film to the sheet material, the number of 1 mm 2 square square adhered portion was measured to calculate the bonding area than the sum of the square. In this case, the adhesive part less than 1 mm 2 was regarded as not adhered. In addition, when an adhesive agent does not adhere to a sheet-like thing, it calculates | requires by the same method using the said square sheet from the fiber-type board surface after peeling a sheet-like thing. Moreover, when an adhesive agent remains on the fiber board surface and the sheet-like material, respectively, the adhesion area is obtained by the same method using the grid sheet from both the fiber board and the sheet-like material. From the above, the adhesion area ratio was determined from the following formula.
Adhesive area ratio (%) = adhesive area (m 2 ) / total surface area of fiber board (m 2 ) × 100.
（実施例１）
ポリ乳酸樹脂を公知の方法で繊維化し、捲縮付与後カットして短繊維が繊度６．６デシテックスで、平均繊維長が５１ｍｍのポリ乳酸短繊維を得た。一方、平均繊維長が７５ｍｍのケナフの靭皮繊維を用意した。このポリ乳酸短繊維とケナフ靭皮繊維とを３０：７０の重量比でローラーカードを用いて混綿し、開繊して不織布を得た。この不織布を２５枚積層し、目付２３５２ｇ／ｍ２の積層体を得た。２枚の鉄板の間に１０ｍｍのスペンサーと共に挟み、２００℃の温度の加熱下のプレス機で圧力２．４ＭＰａ、１０分間加熱加圧成形を行った。得られた繊維系ボードの重量は２２９４ｇ／ｍ２であり、厚さは８．８ｍｍであり、見かけ密度は０．２４ｇ／ｃｍ３であった。得られた繊維系ボードに厚みが９１μｍであり、通気度が０．１５ｍＬ／ｃｍ2・ｓｅｃのパルプ紙を接着面積比率１４％になるように幅１５ｍｍ、長さ１５ｍｍの大きさに接着剤として熱可塑性の樹脂溶液をボード表面に６０ｍｍ間隔で点状に置いて紙と接着し、本発明の吸音材を得た。なお、この際の接着面積比率は１４．１％であった。
Example 1
The polylactic acid resin was fiberized by a known method, cut after crimping, and short fibers were obtained having a fineness of 6.6 dtex and an average fiber length of 51 mm. Meanwhile, a kenaf bast fiber having an average fiber length of 75 mm was prepared. This polylactic acid short fiber and kenaf bast fiber were mixed using a roller card at a weight ratio of 30:70, and opened to obtain a nonwoven fabric. 25 sheets of this nonwoven fabric were laminated to obtain a laminate having a basis weight of 2352 g / m 2 . The steel plate was sandwiched between two steel plates together with a 10 mm spencer, and was subjected to pressure and pressure molding for 10 minutes with a press machine heated at a temperature of 200 ° C. for 10 minutes. The obtained fiber-based board had a weight of 2294 g / m 2 , a thickness of 8.8 mm, and an apparent density of 0.24 g / cm 3 . The obtained fiber-based board has a thickness of 91 μm and an air permeability of 0.15 mL / cm 2 · sec as an adhesive having a width of 15 mm and a length of 15 mm so that the bonding area ratio is 14%. A thermoplastic resin solution was placed on the board surface in the form of dots at intervals of 60 mm and adhered to paper to obtain the sound absorbing material of the present invention. In this case, the adhesion area ratio was 14.1%.
このようにして、得られた紙積層吸音材の特性を表１に示した。この紙積層吸音材は、曲げ強さと吸音性に満足のいくものであった。 The characteristics of the paper laminated sound absorbing material thus obtained are shown in Table 1. This paper laminated sound absorbing material was satisfactory in bending strength and sound absorbing property.
（実施例２）
実施例１の不織布を用い、この不織布を３３枚積層し、目付３３１６ｇ／ｍ２の積層体を得た。この積層体を実施例１と同一の方法にて加圧成形し、重量が３２４９ｇ／ｍ２であり、厚さが９．５ｍｍであり、見かけ密度が０．３３ｇ／ｃｍ３の繊維系ボードを得た。得られた繊維系ボードに厚みが９１μｍであり、通気度が０．１５ｍＬ／ｃｍ2・ｓｅｃのパルプ紙を接着面積比率１４％になるように幅１５ｍｍ、長さ１５ｍｍの大きさに樹脂溶液をボード表面に６０ｍｍ間隔で置いて紙と接着し、本発明の吸音材を得た。
(Example 2)
Using the nonwoven fabric of Example 1, 33 sheets of this nonwoven fabric were laminated to obtain a laminate having a basis weight of 3316 g / m 2 . This laminate was pressure-molded by the same method as in Example 1, and a fiber board having a weight of 3249 g / m 2 , a thickness of 9.5 mm, and an apparent density of 0.33 g / cm 3 was obtained. Obtained. A pulp solution having a thickness of 91 μm and an air permeability of 0.15 mL / cm 2 · sec is applied to the obtained fiber-based board so that the resin solution has a width of 15 mm and a length of 15 mm so that the adhesion area ratio is 14%. It was placed on the surface of the board at intervals of 60 mm and adhered to paper to obtain a sound absorbing material of the present invention.
なお、この際の接着面積比率は１４．５％であった。このようにして、得られた紙積層吸音材の特性を表１に示した。この紙積層吸音材は、曲げ強さと吸音性に優れたものであった。 In this case, the adhesion area ratio was 14.5%. The characteristics of the paper laminated sound absorbing material thus obtained are shown in Table 1. This paper laminated sound absorbing material was excellent in bending strength and sound absorbing property.
（実施例３）
実施例１の不織布を用い、この不織布を４４枚積層し、目付４４４３ｇ／ｍ２の積層体を得た。この積層体を実施例１と同一の方法にて加圧成形し、重量が４３５４ｇ／ｍ２であり、厚さが９．８ｍｍであり、見かけ密度が０．４２ｇ／ｃｍ３の繊維系ボードを得た。得られた繊維系ボードに厚みが９１μｍであり、通気度が０．１５ｍＬ／ｃｍ2・ｓｅｃのパルプ紙を接着面積比率１４％になるように幅１５ｍｍ、長さ１５ｍｍの大きさに樹脂溶液をボード表面に６０ｍｍ間隔で置き、紙と接着した。この際の接着面積比率は１４．１％であった。このようにして、得られた紙積層吸音材の特性を表１に示した。この紙積層吸音材は、特に曲げ強さが１７６２Ｎ／ｃｍ２と大きい上、吸音性にも優れたものであった。
(Example 3)
Using the nonwoven fabric of Example 1, 44 sheets of this nonwoven fabric were laminated to obtain a laminate having a basis weight of 4443 g / m 2 . This laminate was press-molded by the same method as in Example 1, and a fiber board having a weight of 4354 g / m 2 , a thickness of 9.8 mm, and an apparent density of 0.42 g / cm 3 was obtained. Obtained. A pulp solution having a thickness of 91 μm and an air permeability of 0.15 mL / cm 2 · sec is applied to the obtained fiber-based board so that the resin solution has a width of 15 mm and a length of 15 mm so that the adhesion area ratio is 14%. It was placed on the board surface at intervals of 60 mm and adhered to paper. The adhesion area ratio at this time was 14.1%. The characteristics of the paper laminated sound absorbing material thus obtained are shown in Table 1. This paper laminated sound absorbing material had a particularly high bending strength of 1762 N / cm 2 and an excellent sound absorbing property.
（実施例４）
実施例１の不織布を用い、この不織布を５６枚積層し、目付５８１１ｇ／ｍ２の積層体を得た。この積層体を実施例１と同一の方法にて加圧成形し、重量が５６９４ｇ／ｍ２であり、厚さが１０．２ｍｍであり、見かけ密度が０．５７ｇ／ｃｍ３の繊維系ボードを得た。得られた繊維系ボードに厚みが９１μｍであり、通気度が０．１５ｍＬ／ｃｍ2・ｓｅｃのパルプ紙を接着面積比率１４％になるように幅１５ｍｍ、長さ１５ｍｍの大きさに樹脂溶液をボード表面に６０ｍｍ間隔で置き、紙と接着した。この際の接着面積比率は１４．３％であった。このようにして、得られた紙積層吸音材の特性を表１に示した。この紙積層吸音材は、特に曲げ強さが実施例中２８１１Ｎ／ｃｍ２と大きく、吸音性にも優れたものであった。
Example 4
Using the nonwoven fabric of Example 1, 56 sheets of this nonwoven fabric were laminated to obtain a laminate having a basis weight of 5811 g / m 2 . This laminate was press-molded by the same method as in Example 1, and a fiber board having a weight of 5694 g / m 2 , a thickness of 10.2 mm, and an apparent density of 0.57 g / cm 3 was obtained. Obtained. A pulp solution having a thickness of 91 μm and an air permeability of 0.15 mL / cm 2 · sec is applied to the obtained fiber-based board so that the resin solution has a width of 15 mm and a length of 15 mm so that the adhesion area ratio is 14%. It was placed on the board surface at intervals of 60 mm and adhered to paper. The adhesion area ratio at this time was 14.3%. The characteristics of the paper laminated sound absorbing material thus obtained are shown in Table 1. This paper laminated sound-absorbing material had a particularly high bending strength of 2811 N / cm 2 in the examples, and was excellent in sound-absorbing properties.
（比較例１）
実施例１の不織布を用い、この不織布を７枚積層し、目付６５４ｇ／ｍ２の積層体を得た。この積層体を実施例１と同一の方法にて加圧成形し、重量が６４４ｇ／ｍ２であり、厚さが８．７ｍｍであり、見かけ密度が０．０７ｇ／ｃｍ３の繊維系ボードを得た。得られた繊維系ボードに厚みが９１μｍであり、通気度が０．１５ｍＬ／ｃｍ2・ｓｅｃのパルプ紙を接着面積比率１４％になるように幅１５ｍｍ、長さ１５ｍｍの大きさに樹脂溶液をボード表面に６０ｍｍ間隔で置いて紙と接着し、本発明の吸音材を得た。この際の接着面積比率は１３．９％であった。
(Comparative Example 1)
Seven sheets of this nonwoven fabric were laminated | stacked using the nonwoven fabric of Example 1, and the laminated body of 654 g / m < 2 > of fabric weight was obtained. This laminate was press-molded by the same method as in Example 1, and a fiber board having a weight of 644 g / m 2 , a thickness of 8.7 mm, and an apparent density of 0.07 g / cm 3 was obtained. Obtained. A pulp solution having a thickness of 91 μm and an air permeability of 0.15 mL / cm 2 · sec is applied to the obtained fiber-based board so that the resin solution has a width of 15 mm and a length of 15 mm so that the adhesion area ratio is 14%. It was placed on the surface of the board at intervals of 60 mm and adhered to paper to obtain a sound absorbing material of the present invention. The adhesion area ratio at this time was 13.9%.
このようにして、得られた紙積層吸音材の特性を表１に示した。この紙積層吸音材は、吸音性に優れていたが、見かけ密度が低く、曲げ強さに劣るものであった。 The characteristics of the paper laminated sound absorbing material thus obtained are shown in Table 1. This paper laminated sound-absorbing material was excellent in sound-absorbing property, but had a low apparent density and inferior bending strength.
（比較例２）
実施例１の不織布を用い、この不織布を７５枚積層し、目付７６９４ｇ／ｍ２の積層体を得た。この積層体を実施例１と同一の方法にて加圧成形し、重量が７４８６ｇ／ｍ２であり、厚さが１１．０ｍｍであり、見かけ密度が０．７８ｇ／ｃｍ３の繊維系ボードを得た。得られた繊維系ボードに厚みが９１μｍであり、通気度が０．１５ｃｃ／ｃｍ２／ｓｅｃのパルプ紙を接着面積比率１４％になるように幅１５ｍｍ、長さ１５ｍｍの大きさに樹脂溶液をボード表面に６０ｍｍ間隔で置いて紙と接着し、本発明の吸音材を得た。この際の接着面積比率は１４．２％であった。
(Comparative Example 2)
Using the nonwoven fabric of Example 1, 75 sheets of this nonwoven fabric were laminated to obtain a laminate having a basis weight of 7694 g / m 2 . This laminate was press-molded in the same manner as in Example 1, and a fiber board having a weight of 7486 g / m 2 , a thickness of 11.0 mm, and an apparent density of 0.78 g / cm 3 was obtained. Obtained. A pulp solution having a thickness of 91 μm and an air permeability of 0.15 cc / cm 2 / sec is applied to the obtained fiber-based board so that the resin solution has a width of 15 mm and a length of 15 mm so that the adhesion area ratio is 14%. It was placed on the surface of the board at intervals of 60 mm and adhered to paper to obtain a sound absorbing material of the present invention. The adhesion area ratio at this time was 14.2%.
このようにして、得られた紙積層吸音材の特性を表１に示した。この紙積層吸音材は、曲げ強さには優れていたが、繊維系ボードの見かけ密度が高すぎたため吸音性に劣るものであった。 The characteristics of the paper laminated sound absorbing material thus obtained are shown in Table 1. This paper laminated sound-absorbing material was excellent in bending strength but was inferior in sound-absorbing property because the apparent density of the fiber board was too high.
（比較例３）
繊維長７５ｍｍのケナフ靭皮繊維を５ｍｍ径のスクリーンを有する粉砕機に投入し、平均繊維長３ｍｍのケナフ靭皮繊維を得た。ポリ乳酸樹脂を公知の方法で繊維化し、捲縮付与後カットして繊度６．６デシテックス、長さ５ｍｍのポリ乳酸短繊維を得た。得られたケナフ靭皮繊維とポリ乳酸短繊維とをそれぞれ７０：３０の重量比でハンマーミルに投入し、混合して前記原料の混合物を得た。この混合物をベルトコンベアの上にフォーミングし、２枚の鉄板の間に１０ｍｍのスペーサーと共に挟み、２００℃加熱下のプレス機で圧力２．４ＭＰａ、１０分間加熱加圧成型を行った。得られた繊維系ボードの厚さは９．７ｍｍ、密度は０．３４ｇ／ｃｍ３であった。得られた繊維系ボードに厚みが９１μｍであり、通気度が０．１５ｍＬ／ｃｍ2・ｓｅｃのパルプ紙を接着面積比率１４％になるように幅１５ｍｍ、長さ１５ｍｍの大きさに樹脂溶液をボード表面に６０ｍｍ間隔で置いて紙と接着し、本発明の吸音材を得た。この際の接着面積比率は１４．２％であった。
(Comparative Example 3)
A kenaf bast fiber having a fiber length of 75 mm was put into a pulverizer having a screen having a diameter of 5 mm to obtain a kenaf bast fiber having an average fiber length of 3 mm. The polylactic acid resin was fiberized by a known method, and after crimping, it was cut to obtain a polylactic acid short fiber having a fineness of 6.6 dtex and a length of 5 mm. The obtained kenaf bast fiber and polylactic acid short fiber were put into a hammer mill at a weight ratio of 70:30, respectively, and mixed to obtain a mixture of the raw materials. The mixture was formed on a belt conveyor, sandwiched between two iron plates together with a 10 mm spacer, and subjected to pressure and pressure molding for 10 minutes with a press machine heated at 200 ° C. under a pressure of 2.4 MPa. The obtained fiber board had a thickness of 9.7 mm and a density of 0.34 g / cm 3 . A pulp solution having a thickness of 91 μm and an air permeability of 0.15 mL / cm 2 · sec is applied to the obtained fiber-based board so that the resin solution has a width of 15 mm and a length of 15 mm so that the adhesion area ratio is 14%. It was placed on the surface of the board at intervals of 60 mm and adhered to paper to obtain a sound absorbing material of the present invention. The adhesion area ratio at this time was 14.2%.
このようにして、得られた紙積層吸音材の特性を表１に示した。この紙積層吸音材は、吸音性に優れていたが、ケナフ靭皮繊維の平均繊維長が３ｍｍと極端に短いものであったため、曲げ強さに劣るものであった。 The characteristics of the paper laminated sound absorbing material thus obtained are shown in Table 1. This paper laminated sound-absorbing material was excellent in sound-absorbing property, but was inferior in bending strength because the average fiber length of kenaf bast fibers was as extremely short as 3 mm.
（比較例４）
実施例１の不織布を用い、この不織布を５６枚積層し、目付５８１１ｇ／ｍ２の積層体を得た。この積層体を実施例１と同一の方法にて加圧成形し、重量が５６９４ｇ／ｍ２であり、厚さが１０．２ｍｍであり、見かけ密度が０．５７ｇ／ｃｍ３の繊維系ボードを得た。得られた繊維系ボードに厚みが９５μｍであり、通気度が４８．６ｍＬ／ｃｍ2・ｓｅｃのパルプ紙を接着面積比率１４％になるように幅１５ｍｍ、長さ１５ｍｍの大きさに樹脂溶液をボード表面に６０ｍｍ間隔で置き、紙と接着した。この際の接着面積比率は１４．３％であった。
(Comparative Example 4)
Using the nonwoven fabric of Example 1, 56 sheets of this nonwoven fabric were laminated to obtain a laminate having a basis weight of 5811 g / m 2 . This laminate was press-molded by the same method as in Example 1, and a fiber board having a weight of 5694 g / m 2 , a thickness of 10.2 mm, and an apparent density of 0.57 g / cm 3 was obtained. Obtained. A pulp solution having a thickness of 95 μm and an air permeability of 48.6 mL / cm 2 · sec is applied to the obtained fiber-based board so that the resin solution has a width of 15 mm and a length of 15 mm so that the adhesion area ratio is 14%. It was placed on the board surface at intervals of 60 mm and adhered to paper. The adhesion area ratio at this time was 14.3%.
このようにして、得られた紙積層吸音材の特性を表１に示した。この紙積層吸音材は、曲げ強さに優れているが、通気度が高すぎるため吸音性にやや劣るものであった。 The characteristics of the paper laminated sound absorbing material thus obtained are shown in Table 1. This paper laminated sound-absorbing material is excellent in bending strength, but has a slightly inferior sound-absorbing property because the air permeability is too high.
以上の実施例と比較例の値を纏めたのが次の表１である。 Table 1 below summarizes the values of the above examples and comparative examples.
なお、この表の総合評価欄において、「◎」印は周波数２０００Ｈｚの垂直吸音率が０．８０以上で、かつ、曲げ強さが１００Ｎ／ｃｍ２以上の場合を、「○」印は周波数２０００Ｈｚの垂直吸音率が０．７０以上で、かつ、曲げ強さが５０Ｎ／ｃｍ２以上の場合を、「×」印は周波数２０００Ｈｚの垂直吸音率が０．７０未満であるか、又は曲げ強さが５０Ｎ／ｃｍ２未満の場合とした。 In the comprehensive evaluation column of this table, “◎” indicates a case where the vertical sound absorption coefficient at a frequency of 2000 Hz is 0.80 or more and a bending strength is 100 N / cm 2 or more, and “◯” indicates a frequency of 2000 Hz. When the vertical sound absorption coefficient is 0.70 or more and the bending strength is 50 N / cm 2 or more, the symbol “x” indicates that the vertical sound absorption coefficient at a frequency of 2000 Hz is less than 0.70 or the bending strength. Was less than 50 N / cm 2 .
本発明の吸音材は建築材料及び自動車内装材などの吸音材として好適に用いることができる。また、強度を有することで上記分野に限らず幅広い用途に用いられるが、特に曲げ強度が必要とされる最表層材や内面材に好適に用いることができる。 The sound absorbing material of the present invention can be suitably used as a sound absorbing material for building materials and automobile interior materials. Moreover, although it has intensity | strength, it can be used not only for the said field | area but for a wide range of uses, It can use suitably for the outermost layer material and inner surface material in which bending strength is especially required.
Claims (7)
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| JP2007270417A (en) * | 2006-03-07 | 2007-10-18 | Toray Ind Inc | Fiber-based board, furniture, game machine, building material, and method for producing fiber-based board |
| JP2012505978A (en) * | 2008-10-16 | 2012-03-08 | イーマン８ ピーティワイ リミテッド | Composite sound-absorbing material |
| JP2016199827A (en) * | 2015-04-13 | 2016-12-01 | 王子ホールディングス株式会社 | Biodegradable industrial paper |
| US9546439B2 (en) | 2014-05-15 | 2017-01-17 | Zephyros, Inc. | Process of making short fiber nonwoven molded articles |
| US10113322B2 (en) | 2014-12-08 | 2018-10-30 | Zephyros, Inc. | Vertically lapped fibrous flooring |
| US10460715B2 (en) | 2015-01-12 | 2019-10-29 | Zephyros, Inc. | Acoustic floor underlay system |
| WO2020116399A1 (en) * | 2018-12-04 | 2020-06-11 | マクセルホールディングス株式会社 | Method for controlling sound absorbing characteristic of soundproof material |
| US10755686B2 (en) | 2015-01-20 | 2020-08-25 | Zephyros, Inc. | Aluminized faced nonwoven materials |
| US11541626B2 (en) | 2015-05-20 | 2023-01-03 | Zephyros, Inc. | Multi-impedance composite |
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| JP2007270417A (en) * | 2006-03-07 | 2007-10-18 | Toray Ind Inc | Fiber-based board, furniture, game machine, building material, and method for producing fiber-based board |
| JP2012505978A (en) * | 2008-10-16 | 2012-03-08 | イーマン８ ピーティワイ リミテッド | Composite sound-absorbing material |
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| US9623627B2 (en) | 2008-10-16 | 2017-04-18 | Zephyros, Inc. | Composite sound absorber |
| US9546439B2 (en) | 2014-05-15 | 2017-01-17 | Zephyros, Inc. | Process of making short fiber nonwoven molded articles |
| US10329701B2 (en) | 2014-05-15 | 2019-06-25 | Zephyros, Inc. | Method of forming a nonwoven molded article |
| US10113322B2 (en) | 2014-12-08 | 2018-10-30 | Zephyros, Inc. | Vertically lapped fibrous flooring |
| US11542714B2 (en) | 2014-12-08 | 2023-01-03 | Zephyros, Inc. | Vertically lapped fibrous flooring |
| US10460715B2 (en) | 2015-01-12 | 2019-10-29 | Zephyros, Inc. | Acoustic floor underlay system |
| US10755686B2 (en) | 2015-01-20 | 2020-08-25 | Zephyros, Inc. | Aluminized faced nonwoven materials |
| JP2016199827A (en) * | 2015-04-13 | 2016-12-01 | 王子ホールディングス株式会社 | Biodegradable industrial paper |
| US11541626B2 (en) | 2015-05-20 | 2023-01-03 | Zephyros, Inc. | Multi-impedance composite |
| WO2020116399A1 (en) * | 2018-12-04 | 2020-06-11 | マクセルホールディングス株式会社 | Method for controlling sound absorbing characteristic of soundproof material |
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