JP2017082161A - Foam-molded part - Google Patents

Foam-molded part Download PDF

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JP2017082161A
JP2017082161A JP2015214398A JP2015214398A JP2017082161A JP 2017082161 A JP2017082161 A JP 2017082161A JP 2015214398 A JP2015214398 A JP 2015214398A JP 2015214398 A JP2015214398 A JP 2015214398A JP 2017082161 A JP2017082161 A JP 2017082161A
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foam
molded product
bubbles
region
exposed
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JP6631780B2 (en
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輝雄 玉田
Teruo Tamada
輝雄 玉田
孝明 染谷
Takaaki Someya
孝明 染谷
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Kyoraku Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a foam-molded part having sufficient sound absorption performance without being incidental with a sound absorption member and utilizable as light-weight sound absorption stock in an automobile field or the like.SOLUTION: Provided is a foam-molded part having foam at the inside. Its surface is partially provided with a region to which foam is exposed. The region in which the foam is exposed is formed by cutting a surface film. The region in which the foam is exposed to the surface can be formed in such a manner that, when the foam-molded part is molded using a die, by beforehand forming a recessed part at the die, a projecting part is formed at the foam-molded part, and by cutting the projecting part. By forming the region in which the foam is exposed to the surface, sound absorption properties can be imparted to the foam-molded part.SELECTED DRAWING: Figure 1

Description

本発明は、内部に多数の気泡を有する発泡成形品に関するものであり、特に、吸音性能を付与した新規な発泡成形品に関するものである。   The present invention relates to a foam-molded product having a large number of air bubbles therein, and particularly relates to a novel foam-molded product imparted with sound absorbing performance.

発泡成形品として、例えば自動車のインストルメントパネル内に取り付けられる各種空調ダクトが知られている。これら空調ダクトには、発泡した樹脂材料を成形した発泡ダクトが広く用いられている。発泡ダクトは、軽量であり、例えばポリオレフィン系樹脂等の樹脂材料に発泡剤を加えて溶融混練し、押出機のダイから押し出される発泡パリソンをブロー成形することにより容易に製造することができる。   As the foam molded product, for example, various air-conditioning ducts installed in an instrument panel of an automobile are known. For these air conditioning ducts, foam ducts formed by molding a foamed resin material are widely used. The foam duct is lightweight and can be easily manufactured by, for example, adding a foaming agent to a resin material such as polyolefin resin, melt-kneading, and blow-molding a foam parison extruded from a die of an extruder.

あるいは、車室内の各種ボード、パネル、ドアトリム等においても、軽量化や断熱等の目的で、発泡材が広く使用されている。例えばドアトリムは、ドアパネルに内装されて使用され、小型車のバックドアのインナーパネルの穴隠し等として使用されるものである。   Or, various boards, panels, door trims and the like in the passenger compartment are widely used for the purpose of weight reduction and heat insulation. For example, a door trim is used by being embedded in a door panel, and is used as a hole concealment of an inner panel of a back door of a small car.

いずれの用途においても、使用する発泡材には衝撃吸収機能等、様々な機能が要求されるが、近年では、その吸音性能に対する要求も厳しくなってきている。自動車等の車両においては、エンジン音や排気音、ロードノイズ等、様々な音が車室内に入り込んでくる。このような騒音を低減するためには、発泡材も吸音性能や防音性能を有することが必要である。   In any application, the foamed material to be used is required to have various functions such as an impact absorbing function, but in recent years, the requirements for its sound absorbing performance have become stricter. In vehicles such as automobiles, various sounds such as engine noise, exhaust noise, and road noise enter the vehicle interior. In order to reduce such noise, it is necessary that the foam material also has sound absorption performance and sound insulation performance.

ダクトやボード等において、吸音性を改善する方法としては、対象となる周波数の吸音率の高い部材を発泡材に貼り付ける方法が知られている。しかしながら、この場合には、発泡材と異なる材質の吸音部材を付帯させる必要があるため、工数や部品点数が増加するという問題があり、さらには、リサイクル性が悪化するという問題もある。   As a method for improving sound absorption in a duct, a board, or the like, a method is known in which a member having a high sound absorption coefficient at a target frequency is attached to a foam material. However, in this case, since it is necessary to attach a sound absorbing member made of a material different from the foam material, there is a problem that man-hours and the number of parts are increased, and further, there is a problem that recyclability is deteriorated.

このような状況から、発泡材に吸音性能を付与することが検討されている。例えば特許文献1には、熱可塑性樹脂発泡体本体の少なくとも一部の表面から内部に通じる多数の小孔を有する穴あき熱可塑性樹脂発泡体が開示されており、小孔の形状を工夫することで吸音性能の高い穴あき熱可塑性樹脂発泡体とすることが試みられている。発泡材に孔を開けることで吸音性を付与することができれば、特別な吸音部材が不要になり、前記のような様々な問題を解消できるものと期待される。   Under such circumstances, it has been studied to impart sound absorbing performance to the foam material. For example, Patent Document 1 discloses a perforated thermoplastic resin foam having a large number of small holes leading from the surface of at least a part of a thermoplastic resin foam body to the inside, and devises the shape of the small holes. Attempts have been made to produce a perforated thermoplastic resin foam having high sound absorption performance. If sound absorbing properties can be imparted by making holes in the foamed material, it is expected that a special sound absorbing member will be unnecessary and various problems as described above can be solved.

特開2006−265294号公報JP 2006-265294 A

しかしながら、例えば独立気泡を有する発泡材の場合、吸音性に乏しく、十分な吸音性能を付与することが難しいという問題が残っている。特許文献1に記載されるような小孔の形状の工夫では、要求される吸音性能を実現することは難しいのが実情である。   However, for example, in the case of a foam material having closed cells, there remains a problem that sound absorption is poor and it is difficult to provide sufficient sound absorption performance. In reality, it is difficult to achieve the required sound absorption performance with the device of the shape of the small holes as described in Patent Document 1.

本発明は、このような従来の実情に鑑みて提案されたものであり、吸音部材を付帯させることなく、十分な吸音性能を付与することが可能で、自動車分野等において軽量吸音素材として利用することが可能な発泡成形品を提供することを目的とする。   The present invention has been proposed in view of such a conventional situation, and can provide sufficient sound absorbing performance without attaching a sound absorbing member, and is used as a lightweight sound absorbing material in the automotive field and the like. An object of the present invention is to provide a foam molded article that can be used.

前述の目的を達成するために、本発明の発泡成形品は、内部に気泡を有する発泡成形品であって、表面に気泡が露呈した領域を部分的に有することを特徴とするものである。   In order to achieve the above-mentioned object, the foamed molded product of the present invention is a foamed molded product having bubbles inside, and is characterized in that it partially has a region where the bubbles are exposed on the surface.

また、本発明の発泡成形品の製造方法は、内部に気泡を有する発泡成形品の製造方法であって、金型を用いて発泡成形品を成形する際に、金型に凹部を形成しておくことで、発泡成形品に突出部を形成し、前記突出部を切除することにより発泡成形品の表面に気泡が露呈した領域を部分的に形成することを特徴とするものである。   The method for producing a foam molded product of the present invention is a method for producing a foam molded product having bubbles inside, and when forming the foam molded product using a mold, a recess is formed in the mold. Thus, a protruding portion is formed in the foam molded product, and a region where bubbles are exposed is partially formed on the surface of the foam molded product by cutting out the protruding portion.

ブロー成形等により成形される発泡成形品においては、内部に気泡が形成されるものの、表面には、いわゆるスキン層が形成された状態となっており、気泡は吸音性能に寄与しない。本発明においては、例えばスキン層を切除することにより、表面に気泡が露呈した領域を部分的に有する形態となっているので、気泡による吸音性が付与される。   In a foam molded product formed by blow molding or the like, although bubbles are formed inside, a so-called skin layer is formed on the surface, and the bubbles do not contribute to sound absorption performance. In the present invention, for example, by removing the skin layer, the surface is partially provided with a region where air bubbles are exposed, so that sound absorption by the air bubbles is imparted.

本発明によれば、吸音部材を付帯させることなく、十分な吸音性能を有する発泡成形品を実現することができ、自動車分野等において軽量吸音素材として利用することが可能な発泡成形品を提供することが可能である。   ADVANTAGE OF THE INVENTION According to this invention, the foaming molded product which can implement | achieve the foaming molded product which has sufficient sound-absorbing performance, without attaching a sound-absorbing member, and can be utilized as a lightweight sound-absorbing material in the automotive field etc. It is possible.

本発明を適用した発泡成形品の一実施形態を示す概略平面図である。It is a schematic plan view which shows one Embodiment of the foaming molded product to which this invention is applied. 本発明を適用した発泡成形品の他の実施形態を示す概略平面図である。It is a schematic plan view which shows other embodiment of the foaming molded product to which this invention is applied. 金型による成形工程の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the shaping | molding process by a metal mold | die. 突出部の切除工程を示す概略断面図である。It is a schematic sectional drawing which shows the cutting process of a protrusion part. 実施例及び比較例の垂直入射吸音率を示す特性図である。It is a characteristic view which shows the normal incidence sound absorption coefficient of an Example and a comparative example.

以下、本発明を適用した発泡成形品の実施形態について、図面を参照しながら詳細に説明する。   Hereinafter, embodiments of a foam molded product to which the present invention is applied will be described in detail with reference to the drawings.

本発明の発泡成形品は、内部に多数の気泡を有する発泡成形体であり、その形態としては、ボード、パネル、ダクト等、任意である。成形方法も、押出し成形やブロー成形、真空成形、射出成形等、任意である。   The foam-molded article of the present invention is a foam-molded article having a large number of bubbles inside, and the form thereof is arbitrary such as a board, a panel, and a duct. The molding method is also arbitrary such as extrusion molding, blow molding, vacuum molding, injection molding and the like.

例えばブロー成形により形成される発泡成形品を例に説明すると、発泡成形品は、例えば押出機のダイから発泡樹脂を押し出すことによって形成した発泡パリソンを金型で挟んでブロー成形することにより製造される。製造される発泡成形品は、独立気泡構造を有する構成とすることにより、軽量で断熱性に優れたものとすることができる。独立気泡構造とは、複数の独立した気泡セルを有する構造であり、少なくとも独立気泡率が70%以上のものを意味する。   For example, a foam molded product formed by blow molding will be described as an example. A foam molded product is manufactured by, for example, blow molding a foam parison formed by extruding a foam resin from a die of an extruder with a mold. The The foamed molded article to be produced can be made light and excellent in heat insulation by adopting a structure having a closed cell structure. The closed cell structure is a structure having a plurality of independent cell cells, and means a cell having at least a closed cell ratio of 70% or more.

発泡成形品の製造に際しては、原料樹脂に所要の添加剤を加え、ブロー成形に供する。ブロー成形では、物理発泡剤を用いて発泡した発泡樹脂を成形する。物理発泡剤としては、空気、炭酸ガス、窒素ガス、水等の無機系発泡剤や、ブタン、ペンタン、ヘキサン、ジクロロメタン、ジクロロエタン等の有機系発泡剤等を使用することができる。これらの中で、発泡剤としては、空気、炭酸ガス、または窒素ガスを用いることが好ましい。これらを用いることで有機物の混入を防ぐことができ、耐久性等の低下を抑制することができる。   In the production of a foam-molded product, a necessary additive is added to the raw material resin, which is subjected to blow molding. In blow molding, foamed resin is molded using a physical foaming agent. As the physical foaming agent, inorganic foaming agents such as air, carbon dioxide gas, nitrogen gas and water, and organic foaming agents such as butane, pentane, hexane, dichloromethane and dichloroethane can be used. Among these, it is preferable to use air, carbon dioxide gas, or nitrogen gas as the foaming agent. By using these, mixing of organic substances can be prevented, and deterioration of durability and the like can be suppressed.

また、発泡方法としては、超臨界流体を用いることが好ましい。すなわち、炭酸ガスまたは窒素ガスを超臨界状態とし、原料樹脂を発泡させることが好ましい。超臨界流体を用いることで、均一且つ確実に発泡することができる。なお、超臨界流体が窒素ガスの場合の条件としては、例えば臨界温度−149.1℃、臨界圧力3.4MPaとすればよく、超臨界流体が炭酸ガスの場合の条件としては、例えば臨界温度31℃、臨界圧力7.4MPaとすればよい。   Moreover, it is preferable to use a supercritical fluid as the foaming method. That is, it is preferable to make carbon dioxide gas or nitrogen gas into a supercritical state and foam the raw material resin. By using a supercritical fluid, foaming can be performed uniformly and reliably. The conditions when the supercritical fluid is nitrogen gas may be, for example, a critical temperature of 149.1 ° C. and a critical pressure of 3.4 MPa. The conditions when the supercritical fluid is carbon dioxide gas are, for example, the critical temperature. What is necessary is just to set it as 31 degreeC and a critical pressure 7.4MPa.

こうして発泡処理された原料樹脂を公知の方法でブロー成形することにより、発泡成形品を成形する。ブロー成形に際しては、先ず、押出機内で成形に用いる原料樹脂を混練して基材樹脂を作製する。原料樹脂としては、任意の樹脂を採用することが可能であるが、ポリオレフィン系樹脂、例えばポリエチレン系樹脂やポリプロピレン系樹脂等が好適である。ポリエチレン系樹脂としては、低密度ポリエチレン(LDPE)や、高密度ポリエチレン(HDPE)、直鎖状短鎖分岐ポリエチレン(LLDPE)等を用いることができる。また、エチレンやプロピレンと他の共重合性モノマーとの共重合体であってもよい。   The foamed molded product is formed by blow molding the foamed raw material resin by a known method. In blow molding, first, a raw material resin used for molding is kneaded in an extruder to produce a base resin. Although any resin can be adopted as the raw material resin, a polyolefin-based resin such as a polyethylene-based resin or a polypropylene-based resin is preferable. As the polyethylene resin, low density polyethylene (LDPE), high density polyethylene (HDPE), linear short chain branched polyethylene (LLDPE), or the like can be used. Further, it may be a copolymer of ethylene or propylene and another copolymerizable monomer.

原料樹脂(例えばポリオレフィン系樹脂)は、ペレット化して用いるのが一般的であり、原料樹脂ペレットをブロー成形機のホッパーから投入し、シリンダで溶融混練する。この時、必要な添加剤を同時に投入し、原料樹脂と混練する。添加剤としては、分散剤、及び造核剤として機能する無機粒子、化学発泡剤である。   The raw material resin (for example, polyolefin resin) is generally used after being pelletized, and the raw material resin pellet is charged from a hopper of a blow molding machine and melt-kneaded in a cylinder. At this time, necessary additives are simultaneously added and kneaded with the raw material resin. Additives include dispersants, inorganic particles that function as nucleating agents, and chemical foaming agents.

無機粒子と化学発泡剤は、原料樹脂中に発泡核を形成させるために用いられるものであり、造核剤として機能するものである。無機粒子としては、タルクや炭酸カルシウム等を挙げることができるが、その効果が大きいこと、剛性の向上も併せて実現できること等の理由から、タルクが好ましい。化学発泡剤としては、無味無臭で分解残渣が無毒である炭酸水素ナトリウム(重曹)等の無機系の発泡剤が好適である。化学発泡剤としては、クエン酸やクエン酸塩等を併用することもでき。この場合、例えば重曹等を主化学発泡剤、クエン酸等を補助化学発泡剤として添加する。   The inorganic particles and the chemical foaming agent are used for forming foaming nuclei in the raw material resin and function as a nucleating agent. Examples of the inorganic particles include talc and calcium carbonate, and talc is preferable because of its great effect and the achievement of improved rigidity. As the chemical foaming agent, an inorganic foaming agent such as sodium hydrogen carbonate (bicarbonate) having no taste and odor and having no decomposition residue is suitable. As the chemical foaming agent, citric acid or citrate can be used in combination. In this case, for example, sodium bicarbonate is added as the main chemical foaming agent, and citric acid or the like is added as the auxiliary chemical foaming agent.

分散剤は、前記無機粒子や化学発泡剤を原料樹脂中にムラなく分散させるために用いられるものであり、金属石鹸等が用いられる。金属石鹸は、長鎖脂肪酸のナトリウム、カリウム以外の金属塩であり、ステアリン酸石鹸、ヒドロキシステアリン酸石鹸、ラウリン酸石鹸、ベヘン酸石鹸等を挙げることができる。   The dispersant is used for uniformly dispersing the inorganic particles and the chemical foaming agent in the raw material resin, and a metal soap or the like is used. The metal soap is a metal salt other than sodium and potassium long-chain fatty acids, and examples thereof include stearic acid soap, hydroxystearic acid soap, lauric acid soap, and behenic acid soap.

発泡成形に際しては、原料樹脂ペレットに所定の添加量となるように前述の添加剤等を配合し、押出機のシリンダ内で混練した後、ダイ内アキュムレータに貯留し、続いて、所定の樹脂量が貯留された後にリング状ピストンを水平方向に対して直交する方向(垂直方向)に押し下げる。そして、環状ダイのダイスリットより、例えば押出速度700kg/時以上で、円筒状のパリソンとして分割金型の間に押し出す。その後、分割金型を型締してパリソンを挟み込み、さらにパリソン内にエアを吹き込み、発泡成形品を成形する。   At the time of foam molding, the above-mentioned additives are blended into the raw resin pellets so as to have a predetermined addition amount, kneaded in the cylinder of the extruder, stored in an accumulator in the die, and then a predetermined resin amount Is stored, the ring-shaped piston is pushed down in the direction perpendicular to the horizontal direction (vertical direction). And it extrudes between division molds as a cylindrical parison from the die slit of an annular die at an extrusion speed of 700 kg / hour or more, for example. Thereafter, the split mold is clamped to sandwich the parison, and air is blown into the parison to form a foam molded product.

なお、発泡成形品を成形する方法としては、前述のようなブロー成形に限らず、押し出されたパリソンを金型に吸い付けて所定の形状の成形品を成形するバキューム成形を用いても良い。また、エアの吹き込みや吸引を行わず、押し出されたパリソンを金型で挟み込んで成形するコンプレッション成形を用いても良い。   In addition, as a method of shape | molding a foaming molded product, you may use the vacuum shaping | molding which attracts | sucks the extruded parison to a metal mold | die and shape | molds a molded product of a predetermined | prescribed shape. Alternatively, compression molding may be used in which the extruded parison is sandwiched between molds without being blown or sucked.

以上が発泡成形品の基本的な成形方法であるが、次に、成形された発泡成形品に吸音性能を付与する方法について説明する。   The above is the basic method for molding a foam molded product. Next, a method for imparting sound absorbing performance to the molded foam molded product will be described.

先ず、発泡成形品の厚さは、3.0mm以上であることが好ましい。また、発泡倍率は3.0倍以上である。そして、発泡成形品に吸音性能を付与するためには、発泡成形品の表面状態を最適化する必要がある。   First, the thickness of the foam molded product is preferably 3.0 mm or more. The expansion ratio is 3.0 times or more. And in order to provide sound absorption performance to a foam molded product, it is necessary to optimize the surface state of the foam molded product.

成形される発泡成形品は、内部に気泡を有するものであるが、表面には表面被膜(いわゆるスキン層)が形成された状態となっており、内部の気泡は吸音性能にほとんど寄与しない。そこで、本発明においては、この表面のスキン層を切除することで気泡を露呈させ、発泡成形品に吸音性を付与することとする。   The foamed molded article to be molded has air bubbles inside, but a surface film (so-called skin layer) is formed on the surface, and the internal air bubbles hardly contribute to the sound absorbing performance. Therefore, in the present invention, by removing the skin layer on the surface, air bubbles are exposed and sound absorption is imparted to the foam molded product.

図1は、本発明を適用した発泡成形品の一実施形態を示すものである。本実施形態の発泡成形品1は、所定の厚さのボード状の形態を有するものであり、その表面に気泡Bが露呈する領域2が部分的に形成されていることが特徴事項となっている。具体的には、発泡成形品1の表面には、円形の領域2が複数配列形成されている。   FIG. 1 shows an embodiment of a foam molded product to which the present invention is applied. The foamed molded product 1 of the present embodiment has a board-like form with a predetermined thickness, and the region 2 where the bubbles B are exposed is partially formed on the surface thereof. Yes. Specifically, a plurality of circular regions 2 are arranged on the surface of the foam molded product 1.

このように、発泡成形品1の表面に気泡Bが露呈する領域2を部分的に形成することにより、発泡成形品1に吸音性能が付与される。この時、気泡Bが露呈する領域2の形状や大きさは、吸音対象となる音の周波数等により適宜設計すればよいが、例えば領域2の面積は、発泡成形品1の表面面積の10%〜60%とすることが好ましい。領域2の面積が小さすぎたり大きすぎると、十分な吸音性能を付与することが難しい。   In this way, by partially forming the region 2 where the bubbles B are exposed on the surface of the foam molded product 1, sound absorbing performance is imparted to the foam molded product 1. At this time, the shape and size of the region 2 where the bubbles B are exposed may be appropriately designed depending on the frequency of the sound to be absorbed, etc. For example, the area of the region 2 is 10% of the surface area of the foam molded product 1. It is preferable to set it to -60%. If the area of the region 2 is too small or too large, it is difficult to provide sufficient sound absorbing performance.

領域2の形状としては、図1の例では円形としたが、例えば矩形や方形等、任意の形状とすることができる。図2に示す発泡成形品1においては、表面に気泡Bが露呈する領域2が、矩形の領域として複数配列形成されている。図2に示す例では、領域2は概ね長方形状であり、短辺が湾曲形状とされている。   The shape of the region 2 is circular in the example of FIG. 1, but may be any shape such as a rectangle or a rectangle. In the foam molded product 1 shown in FIG. 2, a plurality of regions 2 where the bubbles B are exposed on the surface are formed as a rectangular region. In the example shown in FIG. 2, the region 2 is generally rectangular, and the short side is curved.

また、前記表面に気泡が露呈した領域2において、当該領域に臨む気泡は、表面と直交する方向に引き伸ばされた形状(斜め方向に引き伸ばされたものも含む)であることが好ましい。これにより、吸音性がより向上する。このような形状とするには、後述の製造方法のように、突出部を形成し、これを切除すればよい。   Further, in the region 2 where the bubbles are exposed on the surface, it is preferable that the bubbles facing the region have a shape stretched in a direction perpendicular to the surface (including those stretched in an oblique direction). Thereby, the sound absorption is further improved. In order to obtain such a shape, a protruding portion may be formed and cut off as in the manufacturing method described later.

前述の表面に気泡Bが露呈する領域2は、発泡成形品1の表面のスキン層を切除することにより容易に形成することができる。例えば、図3に示すように、発泡成形品1の成形の際に、金型3に凹部(あるいは孔部)4を形成しておく。この状態で軟化した発泡樹脂材料を成形すると、発泡樹脂材料が金型に押し付けられることにより、その一部が凹部4内に入り込み、突出部1A形成される。なお、成形に際して、前記凹部4において真空吸引し、突出部1Aの形成を促進することも可能である。   The region 2 where the bubbles B are exposed on the surface can be easily formed by cutting away the skin layer on the surface of the foam molded article 1. For example, as shown in FIG. 3, a recess (or hole) 4 is formed in the mold 3 when the foam molded product 1 is molded. When the foamed resin material softened in this state is molded, the foamed resin material is pressed against the mold, so that a part of the foamed resin material enters the recess 4 to form the protruding portion 1A. In the molding, it is possible to suck the vacuum in the concave portion 4 to promote the formation of the protruding portion 1A.

図4に示すように、この突出部1A(図中、斜線部分)を切除することでスキン層が切除され、発泡成形品1の表面に気泡Bが露呈する領域2が凹部4の形状に応じて形成される。例えば、金型3に
形成される凹部4の開口形状を円形とすれば、図1に示すような円形の領域2が形成される。金型3に形成される凹部4の開口形状を長方形とすれば、図2に示すような長方形の領域2が形成される。突出部1Aの切除は、例えばスクレーパーのようなものを用いて行えばよく、複数の突出部1Aを一括して切除することができる。
As shown in FIG. 4, the skin layer is cut by cutting this protruding portion 1 </ b> A (the hatched portion in the drawing), and the region 2 where the bubbles B are exposed on the surface of the foam molded product 1 corresponds to the shape of the recess 4. Formed. For example, if the opening shape of the recess 4 formed in the mold 3 is circular, a circular region 2 as shown in FIG. 1 is formed. If the opening shape of the recess 4 formed in the mold 3 is a rectangle, a rectangular region 2 as shown in FIG. 2 is formed. The projecting portion 1A may be excised using, for example, a scraper, and the plurality of projecting portions 1A can be excised together.

前記突出部1Aの切除により、気泡が外部に連通した状態になり、吸音性に効果を発揮する。前記突出部1Aを形成すると、気泡が突出部1Aの頂部に向かって引き伸ばされる形状となる。そして、突出部1Aの切除により、この引き伸ばされた形状の気泡の切断面が表面に露呈し、外部に連通する。このような形状の気泡が表面に露呈することで、吸音性能が大きく向上するものと推測される。   By cutting out the protruding portion 1A, the air bubbles communicate with the outside, and the sound absorbing effect is exhibited. When the protrusion 1A is formed, the bubbles are stretched toward the top of the protrusion 1A. Then, by cutting off the protruding portion 1A, the expanded cut surface of the bubble is exposed on the surface and communicates with the outside. It is presumed that the sound absorption performance is greatly improved by exposing such shaped bubbles to the surface.

なお、前記突出部1Aの形成において、突出部1Aの高さも吸音性に影響を与える。突出部1Aの高さにより、気泡の引き伸ばし状態が変わることによるものと考えられる。具体的には、前記突出部1Aの高さを1.0mm〜4.0mmとすることが好ましく、2.5mm〜4.0mmとすることがより好ましい。前記範囲とすることで、吸音性向上の効果が高い。突出部1Aの高さが1.0mm未満であると、気泡の引き伸ばしが不十分となり、十分な吸音効果を得ることが難しくなるおそれがある。突出部1Aの高さが4.0mmを越えると、成形が難しくなるおそれがある。   In the formation of the protrusion 1A, the height of the protrusion 1A also affects the sound absorption. It is considered that the expansion state of the bubbles changes depending on the height of the protruding portion 1A. Specifically, the height of the protruding portion 1A is preferably 1.0 mm to 4.0 mm, and more preferably 2.5 mm to 4.0 mm. By setting it as the said range, the effect of a sound absorption improvement is high. If the height of the protruding portion 1A is less than 1.0 mm, the expansion of the bubbles may be insufficient, and it may be difficult to obtain a sufficient sound absorbing effect. If the height of the protruding portion 1A exceeds 4.0 mm, molding may become difficult.

以上のように、本発明の発泡成形品は、表面に気泡が露呈する領域を形成しているので、吸音部材を付帯させることなく、吸音性能を付与することが可能である。したがって、工数や部品点数を増加することなく、またリサイクル性を損なうことなく、十分な吸音性効果を有する軽量吸音素材を提供することが可能である。   As described above, since the foamed molded article of the present invention forms a region where bubbles are exposed on the surface, it is possible to impart sound absorbing performance without attaching a sound absorbing member. Therefore, it is possible to provide a lightweight sound-absorbing material having a sufficient sound-absorbing effect without increasing the number of man-hours and the number of parts and without impairing the recyclability.

以上、本発明を適用した実施形態についてを説明してきたが、本発明が前述の実施形態に限られるものでないことは言うまでもなく、本発明の要旨を逸脱しない範囲において、種々の変更を加えることが可能である。   As mentioned above, although embodiment which applied this invention has been described, it cannot be overemphasized that this invention is not what is limited to the above-mentioned embodiment, In the range which does not deviate from the summary of this invention, a various change can be added. Is possible.

以下、本発明の具体的な実施例について、実験結果を基に説明する。   Hereinafter, specific examples of the present invention will be described based on experimental results.

実施例A−1
図1に示すように、表面に気泡が露呈する領域の形状が円形の発泡成形品(45mm×45mm)を作製した。成形に際しては、突出部の高さが1.0mm〜2.0mmとなるようにして成形し、これを切除した。円形の気泡露呈領域の直径は3mm、発泡成形品における気泡露呈領域の面積率は11.1%である。得られた発泡成形品の吸音率は、周波数2000Hzで5.0%、周波数4000Hzで6.0%であった。
Example A-1
As shown in FIG. 1, a foamed molded product (45 mm × 45 mm) in which the shape of the region where air bubbles are exposed on the surface was circular was produced. At the time of molding, the projecting portion was molded so that the height was 1.0 mm to 2.0 mm, and this was excised. The diameter of the circular bubble exposure region is 3 mm, and the area ratio of the bubble exposure region in the foamed molded product is 11.1%. The sound absorption coefficient of the obtained foamed molded product was 5.0% at a frequency of 2000 Hz and 6.0% at a frequency of 4000 Hz.

実施例A−2
実施例A−1と同様、表面に気泡が露呈する領域の形状が円形の発泡成形品を作製した。成形に際しては、突出部の高さが1.0〜2.0mmとなるようにして成形し、これを切除した。円形の気泡露呈領域の直径は5mm、発泡成形品における気泡露呈領域の面積率は17.4%である。得られた発泡成形品の吸音率は、周波数2000Hzで8.0%、周波数4000Hzで9.0%であった。
Example A-2
As in Example A-1, a foamed molded product having a circular shape in the region where bubbles were exposed on the surface was produced. At the time of molding, the projecting part was shaped so as to have a height of 1.0 to 2.0 mm, and this was excised. The diameter of the circular bubble exposure region is 5 mm, and the area ratio of the bubble exposure region in the foam molded product is 17.4%. The sound absorption coefficient of the obtained foamed molded product was 8.0% at a frequency of 2000 Hz and 9.0% at a frequency of 4000 Hz.

実施例A−3
実施例A−1と同様、表面に気泡が露呈する領域の形状が円形の発泡成形品を作製した。成形に際しては、突出部の高さが1.0〜2.0mmとなるようにして成形し、これを切除した。円形の気泡露呈領域の直径は7mm、発泡成形品における気泡露呈領域の面積率は29.5%である。得られた発泡成形品の吸音率は、周波数2000Hzで13%、周波数4000Hzで20%であった。
Example A-3
As in Example A-1, a foamed molded product having a circular shape in the region where bubbles were exposed on the surface was produced. At the time of molding, the projecting part was shaped so as to have a height of 1.0 to 2.0 mm, and this was excised. The diameter of the circular bubble exposure region is 7 mm, and the area ratio of the bubble exposure region in the foamed molded product is 29.5%. The sound absorption coefficient of the obtained foamed molded product was 13% at a frequency of 2000 Hz and 20% at a frequency of 4000 Hz.

実施例B−2
図1に示すように、表面に気泡が露呈する領域の形状が円形の発泡成形品を作製した。成形に際しては、突出部の高さが2.5mm〜4.0mmとなるようにして成形し、これを切除した。円形の気泡露呈領域の直径は5mm、発泡成形品における気泡露呈領域の面積率は17.4%である。得られた発泡成形品の吸音率は、周波数2000Hzで21%、周波数4000Hzで39%であった。
Example B-2
As shown in FIG. 1, a foam molded product having a circular shape in the region where bubbles are exposed on the surface was produced. At the time of molding, the projecting portion was molded so that the height was 2.5 mm to 4.0 mm, and this was excised. The diameter of the circular bubble exposure region is 5 mm, and the area ratio of the bubble exposure region in the foam molded product is 17.4%. The sound absorption coefficient of the obtained foamed molded product was 21% at a frequency of 2000 Hz and 39% at a frequency of 4000 Hz.

実施例B−3
実施例B−2と同様、表面に気泡が露呈する領域の形状が円形の発泡成形品を作製した。成形に際しては、突出部の高さが2.5mm〜4.0mmとなるようにして成形し、これを切除した。円形の気泡露呈領域の直径は7mm、発泡成形品における気泡露呈領域の面積率は29.5%である。得られた発泡成形品の吸音率は、周波数2000Hzで38%、周波数4000Hzで42%であった。
Example B-3
In the same manner as in Example B-2, a foamed molded product having a circular shape in the region where bubbles were exposed on the surface was produced. At the time of molding, the projecting portion was molded so that the height was 2.5 mm to 4.0 mm, and this was excised. The diameter of the circular bubble exposure region is 7 mm, and the area ratio of the bubble exposure region in the foamed molded product is 29.5%. The sound absorption coefficient of the obtained foamed molded product was 38% at a frequency of 2000 Hz and 42% at a frequency of 4000 Hz.

実施例C
図2に示すように、表面に気泡が露呈する領域の形状が長方形の発泡成形品(45mm×45mm)を作製した。成形に際しては、突出部の高さが2.5mm〜4.0mmとなるようにして成形し、これを切除した。長方形の気泡露呈領域のサイズは、40mm×10mmであり、形成した気泡露呈領域の数は3である。得られた発泡成形品の吸音率は、周波数2000Hzで54%であった。
Example C
As shown in FIG. 2, a foamed molded product (45 mm × 45 mm) having a rectangular shape in which the air bubbles are exposed on the surface was produced. At the time of molding, the projecting portion was molded so that the height was 2.5 mm to 4.0 mm, and this was excised. The size of the rectangular bubble exposure area is 40 mm × 10 mm, and the number of the bubble exposure areas formed is three. The sound absorption coefficient of the obtained foamed molded product was 54% at a frequency of 2000 Hz.

比較例
突出部の形成や切除を行わず、表面に気泡が露呈する領域を形成していない発泡成形品を比較例とした。比較例の発泡成形品の吸音率は、周波数2000Hzで0.7%、周波数4000Hzで3.0%であった。
Comparative Example A foamed molded article in which no protrusions were formed or excised, and no region where air bubbles were exposed on the surface was formed. The sound absorption coefficient of the foamed molded product of the comparative example was 0.7% at a frequency of 2000 Hz and 3.0% at a frequency of 4000 Hz.

作製した各実施例及び比較例の発泡成形品について、垂直入射吸音率の測定結果を図5に示す。いずれの周波数領域においても、比較例の発泡成形品の吸音率に比べて、実施例の発泡成形品の吸音率が高くなっており、表面に気泡が露呈する領域の形成が吸音性の向上に効果があることが明らかである。   FIG. 5 shows the measurement results of the normal incidence sound absorption coefficient for the foamed molded products of the respective examples and comparative examples. In any frequency region, the sound absorption rate of the foamed molded product of the example is higher than the sound absorption rate of the foamed molded product of the comparative example, and the formation of the region in which bubbles are exposed on the surface improves the sound absorption. It is clear that there is an effect.

1 発泡発泡品
2 表面に気泡が露呈する領域
3 金型
4 凹部
B 気泡
DESCRIPTION OF SYMBOLS 1 Foam foam 2 Area | region where air bubbles are exposed on the surface 3 Mold 4 Recessed part B Air bubbles

Claims (6)

内部に気泡を有する発泡成形品であって、表面に気泡が露呈した領域を部分的に有することを特徴とする発泡成形品。   A foam-molded article having bubbles therein, wherein the foam-molded article has a part of the surface where the bubbles are exposed. 前記気泡が露呈した領域は、表面被膜を切除することにより形成されたものであることを特徴とする請求項1記載の発泡成形品。   2. The foamed molded article according to claim 1, wherein the region where the bubbles are exposed is formed by excising a surface coating. 表面に気泡が露呈した領域は、円形の領域、方形の領域、または矩形の領域であることを特徴とする請求項1または2記載の発泡成形品。   The foam molded article according to claim 1 or 2, wherein the area where the air bubbles are exposed on the surface is a circular area, a square area, or a rectangular area. 前記表面に気泡が露呈した領域において、気泡が表面と直交する方向に引き伸ばされた形状であることを特徴とする請求項1から3のいずれか1項記載の発泡成形品。   The foam molded article according to any one of claims 1 to 3, wherein in the region where the bubbles are exposed on the surface, the bubbles are stretched in a direction perpendicular to the surface. 内部に気泡を有する発泡成形品の製造方法であって、
金型を用いて発泡成形品を成形する際に、金型に凹部を形成しておくことで、発泡成形品に突出部を形成し、
前記突出部を切除することにより発泡成形品の表面に気泡が露呈した領域を部分的に形成することを特徴とする発泡成形品の製造方法。
A method for producing a foam molded product having bubbles inside,
When forming a foam molded product using a mold, by forming a recess in the mold, a protrusion is formed on the foam molded product,
A method for producing a foam molded article, wherein a region where bubbles are exposed is partially formed on the surface of the foam molded article by cutting out the protruding portion.
前記突出部の形成により、突出部近傍の気泡が突出部の頂部に向かって引き伸ばされることを特徴とする請求項5記載の発泡成形品の製造方法。   6. The method of manufacturing a foam molded article according to claim 5, wherein the air bubbles in the vicinity of the protrusion are stretched toward the top of the protrusion due to the formation of the protrusion.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020032666A (en) * 2018-08-31 2020-03-05 積水化成品工業株式会社 Resin composite, and manufacturing method of resin composite

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58199149A (en) * 1982-05-15 1983-11-19 松下電工株式会社 Manufacture of building board
JPH03150145A (en) * 1989-11-07 1991-06-26 Chiyuugai:Kk Sound absorbing and insulating material and its manufacture

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58199149A (en) * 1982-05-15 1983-11-19 松下電工株式会社 Manufacture of building board
JPH03150145A (en) * 1989-11-07 1991-06-26 Chiyuugai:Kk Sound absorbing and insulating material and its manufacture

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020032666A (en) * 2018-08-31 2020-03-05 積水化成品工業株式会社 Resin composite, and manufacturing method of resin composite

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