JP6253427B2 - Car article storage member - Google Patents
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- JP6253427B2 JP6253427B2 JP2014016689A JP2014016689A JP6253427B2 JP 6253427 B2 JP6253427 B2 JP 6253427B2 JP 2014016689 A JP2014016689 A JP 2014016689A JP 2014016689 A JP2014016689 A JP 2014016689A JP 6253427 B2 JP6253427 B2 JP 6253427B2
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- 238000003860 storage Methods 0.000 title claims description 132
- 239000002245 particle Substances 0.000 claims description 169
- 229920005992 thermoplastic resin Polymers 0.000 claims description 89
- 239000006260 foam Substances 0.000 claims description 60
- 239000011800 void material Substances 0.000 claims description 49
- 239000012792 core layer Substances 0.000 claims description 45
- 239000010410 layer Substances 0.000 claims description 36
- 239000002344 surface layer Substances 0.000 claims description 32
- 229920005672 polyolefin resin Polymers 0.000 claims description 25
- 239000011247 coating layer Substances 0.000 claims description 23
- 238000000465 moulding Methods 0.000 claims description 22
- 229920005989 resin Polymers 0.000 description 50
- 239000011347 resin Substances 0.000 description 50
- 238000010521 absorption reaction Methods 0.000 description 41
- 238000000034 method Methods 0.000 description 22
- 238000005187 foaming Methods 0.000 description 17
- 239000004088 foaming agent Substances 0.000 description 13
- 239000002612 dispersion medium Substances 0.000 description 12
- 238000005259 measurement Methods 0.000 description 11
- 238000005192 partition Methods 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 9
- -1 polypropylene Polymers 0.000 description 9
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 239000004743 Polypropylene Substances 0.000 description 8
- 230000000630 rising effect Effects 0.000 description 8
- 238000004891 communication Methods 0.000 description 7
- 229920001155 polypropylene Polymers 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 239000004793 Polystyrene Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000011049 filling Methods 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- 239000001569 carbon dioxide Substances 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229920002223 polystyrene Polymers 0.000 description 4
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- 239000011358 absorbing material Substances 0.000 description 3
- 239000002270 dispersing agent Substances 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- XPDWGBQVDMORPB-UHFFFAOYSA-N Fluoroform Chemical compound FC(F)F XPDWGBQVDMORPB-UHFFFAOYSA-N 0.000 description 2
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 239000003570 air Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 229920005606 polypropylene copolymer Polymers 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 229920005653 propylene-ethylene copolymer Polymers 0.000 description 2
- 238000010187 selection method Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- LVGUZGTVOIAKKC-UHFFFAOYSA-N 1,1,1,2-tetrafluoroethane Chemical compound FCC(F)(F)F LVGUZGTVOIAKKC-UHFFFAOYSA-N 0.000 description 1
- AHFMSNDOYCFEPH-UHFFFAOYSA-N 1,2-difluoroethane Chemical compound FCCF AHFMSNDOYCFEPH-UHFFFAOYSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 239000005995 Aluminium silicate Substances 0.000 description 1
- 239000004604 Blowing Agent Substances 0.000 description 1
- XWCDCDSDNJVCLO-UHFFFAOYSA-N Chlorofluoromethane Chemical compound FCCl XWCDCDSDNJVCLO-UHFFFAOYSA-N 0.000 description 1
- PMPVIKIVABFJJI-UHFFFAOYSA-N Cyclobutane Chemical compound C1CCC1 PMPVIKIVABFJJI-UHFFFAOYSA-N 0.000 description 1
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 239000004594 Masterbatch (MB) Substances 0.000 description 1
- 229920007962 Styrene Methyl Methacrylate Polymers 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- 150000004996 alkyl benzenes Chemical class 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 description 1
- HRYZWHHZPQKTII-UHFFFAOYSA-N chloroethane Chemical compound CCCl HRYZWHHZPQKTII-UHFFFAOYSA-N 0.000 description 1
- 239000000805 composite resin Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229960003750 ethyl chloride Drugs 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 235000012438 extruded product Nutrition 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- ADFPJHOAARPYLP-UHFFFAOYSA-N methyl 2-methylprop-2-enoate;styrene Chemical compound COC(=O)C(C)=C.C=CC1=CC=CC=C1 ADFPJHOAARPYLP-UHFFFAOYSA-N 0.000 description 1
- 229940073584 methylene chloride Drugs 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000013518 molded foam Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000002984 plastic foam Substances 0.000 description 1
- 239000000088 plastic resin Substances 0.000 description 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920002285 poly(styrene-co-acrylonitrile) Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920013716 polyethylene resin Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 229920001384 propylene homopolymer Polymers 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229920005792 styrene-acrylic resin Polymers 0.000 description 1
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- BIKXLKXABVUSMH-UHFFFAOYSA-N trizinc;diborate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]B([O-])[O-].[O-]B([O-])[O-] BIKXLKXABVUSMH-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Vehicle Step Arrangements And Article Storage (AREA)
- Molding Of Porous Articles (AREA)
Description
本発明は、自動車用物品収納部材に関し、より詳しくは、自動車のトランクルーム等に設置可能な自動車用物品収納部材に関する。 The present invention relates to an automobile article storage member, and more particularly to an automobile article storage member that can be installed in a trunk room of an automobile.
自動車には、一般的に、トランクルーム内等の所定位置に物品収納部材が設置されている。物品収納部材としては、例えば、ラゲッジボックス、ラゲッジトレイ、ツールボックスなどが挙げられ、荷物や工具、その他の物品等を収納可能に構成されて、自動車のトランクルーム内等に配置される。これらの物品収納部材としては、強度と耐衝撃性を有しつつ軽量性に優れる点で、ポリプロピレン系樹脂発泡粒子成形体にて構成されているものが提案されている（特許文献１）。 In general, an article storage member is installed in a predetermined position such as in a trunk room in an automobile. Examples of the article storage member include a luggage box, a luggage tray, a tool box, and the like. The article storage member is configured to store luggage, tools, other articles, and the like, and is arranged in a trunk room of an automobile. As these article storage members, those composed of a polypropylene resin foam particle molded body have been proposed in that they have strength and impact resistance and are excellent in light weight (Patent Document 1).
ところで、自動車には、ハイブリッド車や電気自動車など、電気モーターと減速機を有して構成されるパワーユニットを装備したものが増えてきている。パワーユニットは、通常、自動車の後方側にあるトランクルームの、下方側の所定位置に配置される。このような自動車において、電気モーターなどパワーユニットを形成する各部から高周波音が発生することが指摘されている。 By the way, an automobile equipped with a power unit including an electric motor and a speed reducer, such as a hybrid car and an electric car, is increasing. The power unit is usually arranged at a predetermined position on the lower side of the trunk room on the rear side of the automobile. In such an automobile, it has been pointed out that high-frequency sound is generated from each part forming a power unit such as an electric motor.
ところが、自動車用の物品収納部材として汎用されるポリプロピレン系樹脂発泡粒子成形体は、吸音性能の観点からは課題を残すものであった。したがって、近年、自動車においては、トランクルームなど物品収納部材の配置された部分から車室内に高周波音が漏れてしまうという高周波音域（たとえば、７ｋＨｚ以上、さらには９〜１０ｋＨｚ程度の音域における）の音漏れの問題が存在していた。 However, the polypropylene resin expanded resin molded body generally used as an article storage member for automobiles has a problem from the viewpoint of sound absorption performance. Therefore, in recent years, in automobiles, sound leakage in a high-frequency sound range (for example, in a sound range of 7 kHz or more, or about 9 to 10 kHz) in which high-frequency sound leaks from a portion where an article storage member such as a trunk room is disposed into the vehicle interior. There was a problem.
このような、トランクルームから車室内に高周波音が漏れ伝わってくるという騒音の問題を解消するため、ポリプロピレン系樹脂発泡粒子成形体からなる物品収納部材に対して別途準備された吸音材を設置する試みが実施される。しかしながら、このような試みでは、自動車の製造工程が煩雑となり製造コストの上昇を招くうえ、トランクルームの空間の一部を吸音材の設置に割り当てざるを得なくなりトランクルームとして活用できるスペースが狭くなるという問題がある。 In order to eliminate the problem of high-frequency sound leaking from the trunk room to the passenger compartment, an attempt is made to install a separately prepared sound-absorbing material for the article housing member made of a polypropylene resin foam particle molded body. Is implemented. However, in such an attempt, the manufacturing process of the automobile becomes complicated, leading to an increase in manufacturing cost, and a part of the space of the trunk room has to be allocated to the installation of the sound absorbing material, and the space that can be used as the trunk room becomes narrow. There is.
本発明は、軽量性に優れ、且つ、高周波音域の吸音性に優れる自動車用物品収納部材を提供する、ことを目的とする。 An object of the present invention is to provide an article storage member for automobiles that is excellent in light weight and excellent in sound absorption in a high frequency sound range.
本発明は、
（１）熱可塑性樹脂発泡粒子成形体からなり、上方に開口した凹状の収納部を有する自動車用物品収納部材において、
該物品収納部材は、少なくとも下面側に、連通した空隙を有する熱可塑性樹脂発泡粒子成形体で形成された吸音層を有しており、
該連通した空隙を有する熱可塑性樹脂発泡粒子成形体全体の空隙率が１５％以上５０％以下であり、該連通した空隙を有する熱可塑性樹脂発泡粒子成形体の表層部分の空隙率が１５％以上であり、
該表層部分の空隙率が、該表層部分を除いた成形体の内部の空隙率よりも大きい、または、該表層部分の空隙率と該成形体の内部の空隙率とが等しい、ことを特徴とする自動車用物品収納部材、
（２）前記連通した空隙を有する熱可塑性樹脂発泡粒子成形体の表層部分の空隙率が２０％以上４５％以下である、上記（１）に記載の自動車用物品収納部材、
（３）前記連通した空隙を有する熱可塑性樹脂発泡粒子成形体の最小厚みが１０ｍｍ以上４０ｍｍ以下である、上記（１）または（２）に記載の自動車用物品収納部材、
（４）前記連通した空隙を有する熱可塑性樹脂発泡粒子成形体の密度が０．０１ｇ／ｃｍ3以上０．２ｇ／ｃｍ3以下である、上記（１）から（３）のいずれかに記載の自動車用物品収納部材、
（５）前記連通した空隙を有する熱可塑性樹脂発泡粒子成形体は、貫通孔を有する熱可塑性樹脂発泡粒子を型内成形してなる、上記（１）から（４）のいずれかに記載の自動車用物品収納部材、
（６）前記連通した空隙を有する熱可塑性樹脂発泡粒子成形体の気泡膜厚が５μｍ以下である、上記（１）から（５）のいずれかに記載の自動車用物品収納部材、
（７）前記連通した空隙を有する熱可塑性樹脂発泡粒子成形体は、ポリオレフィン系樹脂発泡粒子を型内成形してなる、上記（１）から（６）のいずれかに記載の自動車用物品収納部材、
（８）前記連通した空隙を有する熱可塑性樹脂発泡粒子成形体は、筒状のポリオレフィン系樹脂発泡芯層と該発泡芯層を被覆するポリオレフィン系樹脂被覆層とからなる多層構造の発泡粒子を型内成形してなる、上記（１）から（６）のいずれかに記載の自動車用物品収納部材、を要旨とする。
The present invention
(1) In an automotive article storage member comprising a thermoplastic resin foam particle molded body and having a concave storage portion opened upward,
The article storage member has, on at least the lower surface side, a sound absorbing layer formed of a thermoplastic resin foamed particle molded body having a continuous void.
The porosity of the entire thermoplastic resin foam particle molded body having the continuous voids is 15% or more and 50% or less, and the porosity of the surface layer portion of the thermoplastic resin foam particle molded body having the continuous voids is 15% or more. der is,
The porosity of the surface layer portion is larger than the porosity of the molded body excluding the surface layer portion, or the porosity of the surface layer portion and the porosity of the molded body are equal. Automotive article storage member
(2) The article storage member for automobiles according to (1), wherein the porosity of the surface layer portion of the thermoplastic resin foam particle molded body having the communicating voids is 20% or more and 45% or less,
(3) The automobile article storage member according to the above (1) or (2), wherein a minimum thickness of the thermoplastic resin foamed particle molded body having the communicating voids is 10 mm or more and 40 mm or less,
(4) The density of the thermoplastic resin expanded particle molded body having the communicating void is 0.01 g / cm 3 or more and 0.2 g / cm 3 or less, according to any one of (1) to (3) above. Automotive article storage members,
(5) The automobile according to any one of (1) to (4), wherein the molded foam of thermoplastic resin particles having the communicating voids is formed by molding the expanded thermoplastic resin particles having through holes in a mold. Article storage member,
(6) The automotive article storage member according to any one of (1) to (5) above, wherein the foamed thermoplastic resin particle molded body having the communicating voids has a cell thickness of 5 μm or less.
(7) The molded article for thermoplastic resin foamed particles having the communicating voids is obtained by molding the polyolefin resin foamed particles in a mold, and the automotive article storage member according to any one of (1) to (6) above ,
(8) The thermoplastic resin foamed particle molded body having the communicating voids is formed by molding foamed particles having a multilayer structure comprising a cylindrical polyolefin resin foam core layer and a polyolefin resin cover layer covering the foam core layer. The gist of the automobile article storage member according to any one of (1) to (6), which is formed by internal molding.
本発明によれば、軽量性に優れ、且つ、高周波音の吸音性に優れる自動車用物品収納部材が提供される。 ADVANTAGE OF THE INVENTION According to this invention, the articles | goods storage member for motor vehicles which is excellent in lightweight property and excellent in the sound-absorbing property of a high frequency sound is provided.
［物品収納部材１］
本発明の物品収納部材１は、所望の物品を収納可能な空間を形成したものである。物品収納部材１は、図１Ａ，図２に示すように、下面２側には、連通した空隙を有する熱可塑性樹脂発泡粒子成形体により形成された吸音層２３を有する。また、上面３側には、図１Ａ，図２の例に示すように、物品を収納可能な、上方に開口した、凹状の収納部２１が形成されている。さらに、物品収納部材１の上面側には、収納部２１を被覆する蓋材１２が取り付けられているが、蓋材１２は適宜備えられてよいものである。したがって、物品収納部材１は、蓋材１２で覆われずに物品収納部材１の上面３側を外方に露出させるものとされてもよい。蓋材１２は物品収納部材１の上面３の一部を覆うように構成されてもよい。また、物品収納部材１は、熱可塑性樹脂発泡粒子成形体に対して蓋材１２を回動自在に固定されてもよい。なお、物品収納部材１の上面３側とは、物品収納部材１が自動車に取り付けられた状態を想定した場合に物品収納部材１のうち車体上側を向く面を示すものとする。また、物品収納部材１の下面２側は、上面３側とは逆面側を示す。
[Article storage member 1]
The article storage member 1 of the present invention forms a space in which a desired article can be stored. As shown in FIGS. 1A and 2, the article storage member 1 has a sound absorbing layer 23 formed of a thermoplastic resin foamed particle molded body having a communicating void on the lower surface 2 side. Moreover, as shown in the example of FIG. 1A and FIG. 2, the upper surface 3 side is formed with a concave storage portion 21 that is open upward and can store articles. Furthermore, a lid member 12 that covers the storage portion 21 is attached to the upper surface side of the article storage member 1, but the lid member 12 may be appropriately provided. Therefore, the article storage member 1 may be exposed to the outside on the upper surface 3 side of the article storage member 1 without being covered with the lid member 12. The lid member 12 may be configured to cover a part of the upper surface 3 of the article storage member 1. Moreover, the article | item storage member 1 may fix the lid | cover material 12 rotatably with respect to a thermoplastic resin foam particle molded object. Note that the upper surface 3 side of the article storage member 1 indicates a surface of the article storage member 1 that faces the upper side of the vehicle body when it is assumed that the article storage member 1 is attached to an automobile. Further, the lower surface 2 side of the article storage member 1 indicates the opposite surface side to the upper surface 3 side.
物品収納部材１が、図１Ａ、図２に示すような、側壁４と仕切り壁５とを有するボックスタイプの物である場合を例として、さらに物品収納部材１について説明する。 The article storage member 1 will be further described by taking as an example the case where the article storage member 1 is a box-type object having a side wall 4 and a partition wall 5 as shown in FIGS. 1A and 2.
図２の例では、物品収納部材１の下面２側に、連通した空隙を有する熱可塑性樹脂発泡粒子成形体で形成された吸音層２３を形成する底面部２２が直方体形状の薄板状に形成されている。さらに底面部２２から物品収納部材１の上面３側に向けて、底面部２２の周縁に沿って立ち上がった側壁４と、側壁４で囲まれた空間を仕切る仕切り壁５とが備えられることで、凹状の収納部２１が形成される。なお、図１、図２の例は物品収納部材の一例であって、このような形状及び構成に限定されず、物品収納部材を設置するためのスペースの状況に応じて適宜特定されればよい。 In the example of FIG. 2, a bottom surface portion 22 that forms a sound absorbing layer 23 formed of a thermoplastic resin foam particle molded body having a communicating void is formed in a rectangular parallelepiped thin plate shape on the lower surface 2 side of the article storage member 1. ing. Furthermore, by providing the side wall 4 rising along the periphery of the bottom surface portion 22 from the bottom surface portion 22 toward the upper surface 3 side of the article storage member 1, and the partition wall 5 that partitions the space surrounded by the side wall 4, A concave storage portion 21 is formed. The examples of FIGS. 1 and 2 are examples of the article storage member, and are not limited to such shapes and configurations, and may be appropriately specified according to the situation of the space for installing the article storage member. .
なお、収納部２１の形状は、上方に開口された凹形状であれば適宜選択可能であり、例えば、図６に示すように、開口部２１の形状は、その断面形状が湾曲状となるように形成されてよい。さらに、開口部２１が複数存在する場合においては、その断面形状が湾曲状となるように形成されているものと、非湾曲状に形成されているものが組み合わされてよい。 The shape of the storage portion 21 can be selected as appropriate as long as it is a concave shape opened upward. For example, as shown in FIG. 6, the shape of the opening portion 21 is such that its cross-sectional shape is curved. May be formed. Further, in the case where there are a plurality of openings 21, those formed so that the cross-sectional shape is curved and those formed non-curved may be combined.
本発明の物品収納部材１は、熱可塑性樹脂発泡粒子成形体（以下、単に、発泡粒子成形体、成形体ということがある）からなる。なお、物品収納部材１の下面側にて吸音層２３を形成する成形体であり連通した空隙を有する熱可塑性樹脂発泡粒子成形体と、吸音層２３以外の部分を形成する熱可塑性樹脂発泡粒子成形体とは、一体的に形成されてよい。また、発泡粒子成形体は、下面側にて吸音層２３を形成する成形体であり連通した空隙を有する熱可塑性樹脂発泡粒子成形体と、吸音層２３以外の部分を形成する熱可塑性樹脂発泡粒子成形体とを別体にて成形して、これらの成形体を相互に位置あわせして固定、接着等により形成されたものであってもよい。また、物品収納部材１は、下面側に吸音層２３を形成する成形体であり連通した空隙を有する熱可塑性樹脂発泡粒子成形体が、吸音層２３以外の部分を形成する熱可塑性樹脂発泡粒子成形体をも兼ねるように構成されていてもよい。 The article storage member 1 of the present invention is made of a thermoplastic resin foamed particle molded body (hereinafter sometimes simply referred to as a foamed particle molded body or a molded body). In addition, it is the molded object which forms the sound absorption layer 23 in the lower surface side of the article | item storage member 1, and is the thermoplastic resin foam particle molded object which has the space | gap which connected, and the thermoplastic resin foam particle molding which forms parts other than the sound absorption layer 23 The body may be integrally formed. The foamed particle molded body is a molded body that forms the sound absorbing layer 23 on the lower surface side, and is a thermoplastic resin foamed particle molded body having a communicating void, and a thermoplastic resin foamed particle that forms a part other than the sound absorbing layer 23. The molded body may be formed separately from the molded body, and these molded bodies may be aligned with each other and fixed, bonded, or the like. The article storage member 1 is a molded body for forming the sound absorbing layer 23 on the lower surface side, and the thermoplastic resin foamed particle molded body having a communicating void forms a portion other than the sound absorbing layer 23. You may be comprised so that it may serve as a body.
吸音層２３を形成する成形体であり連通した空隙を有する熱可塑性樹脂発泡粒子成形体と、吸音層２３以外の部分を形成する熱可塑性樹脂発泡粒子成形体を構成する熱可塑性樹脂は、互いに同種の樹脂でも、異種の樹脂で構成されてもよい。物品収納部材１は、熱可塑性樹脂発泡粒子成形体で構成されることにより、軽量性と耐衝撃性に優れた物品収納部材となる。上記強度と耐衝撃性の観点からは、物品収納部材１をなす発泡粒子成形体は、ポリオレフィン系樹脂発泡粒子成形体であることが好ましい。 The thermoplastic resin foamed particle molded body that is a molded body that forms the sound-absorbing layer 23 and that has a communicating void, and the thermoplastic resin that constitutes the thermoplastic resin foamed-particle molded body that forms a part other than the sound absorbing layer 23 are the same type of each other. Or different types of resins. The article storage member 1 is an article storage member that is excellent in light weight and impact resistance by being formed of a thermoplastic resin foam particle molded body. From the viewpoint of the strength and impact resistance, the foamed particle molded body forming the article housing member 1 is preferably a polyolefin resin foamed particle molded body.
また、具体的に、例えば、物品収納部材１が、底面部２２と、底面部２２の周縁に沿って上面３側に立ち上がった側壁４と、側壁４で囲まれた空間を仕切る仕切り壁５とで形成された凹状の収納部２１を備える場合において、物品収納部材１の底面部２２に対応する部分を、連通した空隙を有する熱可塑性樹脂発泡粒子成形体で構成し、側壁４と仕切り壁５などの吸音層２３以外の部分を熱可塑性樹脂発泡粒子成形体で構成してよい。また、物品収納部材１の底面部２２に対応する部分と、側壁４と仕切り壁５のいずれについても、連通した空隙を有する熱可塑性樹脂発泡粒子成形体で構成されてよい。これらのいずれの場合でも、物品収納部材１の下面２側の少なくとも底面部２２が、連通した空隙を有する熱可塑性樹脂発泡粒子成形体で形成されることとなり、連通した空隙を有する熱可塑性樹脂発泡粒子成形体で構成された部分が吸音層２３をなすことになる。 Specifically, for example, the article storage member 1 includes a bottom surface portion 22, a side wall 4 that rises toward the top surface 3 along the periphery of the bottom surface portion 22, and a partition wall 5 that partitions a space surrounded by the side walls 4. In the case of including the concave storage portion 21 formed by the above, the portion corresponding to the bottom surface portion 22 of the article storage member 1 is formed of a thermoplastic resin foamed particle molded body having a communicating gap, and the side wall 4 and the partition wall 5 are formed. A part other than the sound absorbing layer 23 such as a thermoplastic resin foamed particle molded body may be formed. Moreover, you may be comprised with the part corresponding to the bottom face part 22 of the article | item storage member 1, and the side wall 4 and the partition wall 5 with the thermoplastic resin expanded particle molded object which has the space | gap which connected. In any of these cases, at least the bottom surface portion 22 on the lower surface 2 side of the article storage member 1 is formed of a thermoplastic resin foamed particle molded body having a continuous void, and the thermoplastic resin foam having a continuous void is formed. The part constituted by the particle compact forms the sound absorbing layer 23.
なお、物品収納部材１をなす発泡粒子成形体は、多数の発泡粒子を型内成形して得られる発泡粒子型内成形体であることが好ましい。この場合、発泡粒子成形体は、発泡粒子同士が加熱融着された構造を有する。このような成形体は、例えば、特開平２−２９９８２２号公報、特開平５−１４７１２０号公報などに記載されている方法を適宜用いて複数個の発泡粒子を型内成形することによって、具体的に成形することができる。 In addition, it is preferable that the expanded particle molded object which comprises the article | item storage member 1 is an expanded particle in-mold molded object obtained by shape-molding many expanded particles. In this case, the foamed particle molded body has a structure in which the foamed particles are heat-sealed. Such a molded body is concretely formed by, for example, molding a plurality of expanded particles in a mold appropriately using a method described in JP-A-2-299822, JP-A-5-147120, or the like. Can be molded.
（連通した空隙を有する成形体）
物品収納部材１の少なくとも下面２側の吸音層２３は、熱可塑性樹脂発泡粒子（発泡粒子と呼ぶことがある）で形成されており、且つ連通した空隙を有する成形体（連通空隙保有成形体６（以下、単に、成形体６と呼ぶことがある））にて形成されている。また、前記吸音層２３は、連通した空隙を有する本発明で規定する成形体により形成されていればよく、密度や空隙率が異なる複数種の成形体からなるものであってもよい。なお、物品収納部材１全体が、連通した空隙を有する成形体で形成されてよい。物品収納部材１の少なくとも下面２側が連通した空隙を有する熱可塑性樹脂発泡粒子成形体で形成されることにより、物品収納部材１は優れた吸音性を発揮する。上記観点から、連通空隙保有成形体６は、物品収納部材の下面２の全面を構成するように形成されることが好ましい。
(Molded body with continuous voids)
The sound absorbing layer 23 on at least the lower surface 2 side of the article storage member 1 is formed of thermoplastic resin foamed particles (sometimes referred to as foamed particles), and a molded body having a continuous void (communication void holding molded body 6). (Hereinafter, sometimes simply referred to as the molded body 6)). Further, the sound absorbing layer 23 may be formed of a molded body defined by the present invention having a continuous void, and may be formed of a plurality of types of molded bodies having different densities and void ratios. Note that the entire article storage member 1 may be formed of a molded body having a communicating gap. The article storage member 1 exhibits an excellent sound absorbing property by being formed of a thermoplastic resin foamed particle molded body having a space where at least the lower surface 2 side of the article storage member 1 communicates. From the above viewpoint, the communicating void-containing molded body 6 is preferably formed so as to constitute the entire lower surface 2 of the article storage member.
なお、連通した空隙を有する熱可塑性樹脂発泡粒子成形体を得るための方法としては、例えば、（ｉ）貫通孔を有する熱可塑性樹脂発泡粒子を金型内に充填し、加熱することにより発泡粒子同士を融着させ、前記貫通孔による連通した空隙を形成する方法、（ｉｉ）熱可塑性樹脂発泡粒子を金型内に充填し、充填時の発泡粒子間の空隙がなくならないように発泡粒子を加熱して発泡粒子同士の一部を互いに融着させることにより発泡粒子間に連通した空隙を形成する方法、（ｉｉｉ）円柱状または楕円柱状であり、その半径に対する長さの比が大きい熱可塑性樹脂発泡粒子を用いて型内成形体を得る方法や、（ｉｖ）これらの方法を組み合わせることによって粒子間の空隙や貫通孔による空隙の両方を形成する方法などが挙げられる。物品収納部材１の下面２側が連通空隙保有成形体６で形成されることにより、物品収納部材１を備えた自動車においてその自動車のパワーユニット等から発生する高周波音は、物品収納部材１の下面２側の連通空隙保有成形体６で効果的に吸音されて、高周波音の車室内側への伝播を抑制させることが可能となる。 In addition, as a method for obtaining a thermoplastic resin foamed particle molded body having continuous voids, for example, (i) a foamed particle is prepared by filling a mold with thermoplastic resin foamed particles having through holes and heating. (Ii) filling the thermoplastic resin foam particles in a mold and forming the foam particles so that the voids between the foam particles at the time of filling are not lost. A method of forming voids communicating between the expanded particles by fusing part of the expanded particles to each other by heating; (iii) cylindrical or elliptical column, and a thermoplastic having a large ratio of length to radius Examples thereof include a method of obtaining an in-mold molded body using resin foam particles, and (iv) a method of forming both voids between particles and voids by through holes by combining these methods. Since the lower surface 2 side of the article storage member 1 is formed by the communication gap possessing molded body 6, the high frequency sound generated from the power unit of the automobile in the vehicle equipped with the article storage member 1 is reduced to the lower surface 2 side of the article storage member 1. It is possible to effectively absorb the sound by the communicating gap possessing molded body 6 and to suppress the propagation of the high frequency sound to the vehicle interior side.
（連通した空隙を有する成形体の厚み）
連通した空隙を有する成形体（連通空隙保有成形体６）の最小厚み（図２において符号Ｗにて示す）は１０ｍｍ以上６０ｍｍ以下であることが好ましい。連通した空隙を有する成形体の最小厚みが上記範囲内であることにより、物品収納部材１の軽量性を有しつつ、吸音性を担保することが可能となる。さらに、耐衝撃性の観点からは、連通した空隙を有する成形体の最小厚みは１２ｍｍ以上であることが好ましく、１５ｍｍ以上であることがさらに好ましい。また、物品収納部材１の車内収納性の観点からは、最小厚みは５０ｍｍ以下であることが好ましく、４５ｍｍ以下であることがさらに好ましく、４０ｍｍ以下がもっとも好ましい。本発明においては、下面２側を形成する成形体として連通した空隙を有する成形体の最小厚みが比較的薄い場合であっても、特定の連通した空隙を有する発泡粒子成形体で構成されているので、優れた吸音性能が発揮される。
(Thickness of the molded body having a continuous void)
It is preferable that the minimum thickness (indicated by the symbol W in FIG. 2) of the molded body having the communicating voids (communication void-containing molded body 6) is 10 mm or more and 60 mm or less. When the minimum thickness of the molded body having the communicating voids is within the above range, it is possible to ensure sound absorption while having the light weight of the article storage member 1. Furthermore, from the viewpoint of impact resistance, the minimum thickness of the molded body having a continuous void is preferably 12 mm or more, and more preferably 15 mm or more. Moreover, from the viewpoint of in-vehicle storage of the article storage member 1, the minimum thickness is preferably 50 mm or less, more preferably 45 mm or less, and most preferably 40 mm or less. In the present invention, even if the minimum thickness of the molded body having a continuous void as the molded body forming the lower surface 2 side is relatively thin, the molded body is formed of a foamed particle molded body having a specific continuous void. Therefore, excellent sound absorption performance is demonstrated.
なお、連通した空隙を有する成形体の最小厚みは、次のように特定される。すなわち、連通した空隙を有する成形体における、物品収納部材１の下面２側から、物品収納部材１の上面３側への上下方向厚みの最小値をいう。例えば、図２の例では、物品収納部材１のうち収納部２１を形成する部分において底面部２２の下面２側表面から底面部２２の上面３側表面までの厚みＷが最小厚みとなっている。なお、図２の例のように収納部２１が複数個所存在する場合には、それぞれの収納部２１について同様の測定を行い、それらの測定値のち、最小の値を求める。 In addition, the minimum thickness of the molded object which has the space | gap which connected is specified as follows. That is, it refers to the minimum value of the thickness in the vertical direction from the lower surface 2 side of the article storage member 1 to the upper surface 3 side of the article storage member 1 in the molded body having the communicating void. For example, in the example of FIG. 2, the thickness W from the lower surface 2 side surface of the bottom surface portion 22 to the upper surface 3 side surface of the bottom surface portion 22 is the minimum thickness in the portion of the article storage member 1 where the storage portion 21 is formed. . When there are a plurality of storage units 21 as in the example of FIG. 2, the same measurement is performed for each storage unit 21, and the minimum value is obtained from these measured values.
なお、図６の例では、下面２側の表面から、収納部２１の最深部、すなわち破線Ｄの位置までの範囲で特定される部分までの厚みが、連通した空隙を有する成形体最小厚みとなる。 In the example of FIG. 6, the thickness from the surface on the lower surface 2 side to the deepest portion of the storage portion 21, that is, the portion specified in the range from the position of the broken line D, is the minimum thickness of the molded body having a continuous gap. Become.
（連通した空隙を有する成形体の密度）
連通した空隙を有する成形体（連通空隙保有成形体６）の密度は、０．０１ｇ／ｃｍ３以上０．２ｇ／ｃｍ３以下であることが好ましい。前記連通した空隙を有する成形体６の密度がこのような範囲内であれば、強度と軽量性を併せ持つ物品収納部材１となる。上記観点から、０．０１５〜０．１ｇ／ｃｍ３であることがより好ましく、０．０２〜０．０８ｇ／ｃｍ３であることがさらに好ましい。
(Density of compacts with continuous voids)
It is preferable that the density of the molded body having a continuous void (communication void-containing molded body 6) is 0.01 g / cm 3 or more and 0.2 g / cm 3 or less. When the density of the molded body 6 having the communicating voids is within such a range, the article storage member 1 having both strength and lightness is obtained. In view of the above, more preferably 0.015~0.1g / cm 3, further preferably 0.02 to 0.08 g / cm 3.
連通した空隙を有する成形体６の密度は、次のように特定される。すなわち、連通した空隙を有する成形体から所定寸法のカットサンプルを切り出し、そのカットサンプルの外形寸法を測定して体積（ｃｍ３）を算出するとともに、カットサンプルの重量（ｇ）を測定する。そして、カットサンプルの体積Ｖ（ｃｍ３）でカットサンプルの重量Ｍ（ｇ）を除することによりＭ／Ｖを算出する。そして、連通した空隙を有する成形体から任意に５箇所以上を選択して切り出されたカットサンプルごとに算出されたＭ／Ｖの値を算術平均する。こうして得られた算術平均値が、前記連通した空隙を有する成形体の密度とされる。 The density of the molded body 6 having the communicating voids is specified as follows. That is, a cut sample having a predetermined size is cut out from a molded body having a continuous gap, and the external dimensions of the cut sample are measured to calculate the volume (cm 3 ), and the weight (g) of the cut sample is measured. Then, M / V is calculated by dividing the weight M (g) of the cut sample by the volume V (cm 3 ) of the cut sample. Then, the arithmetic average of the M / V values calculated for each cut sample cut out by arbitrarily selecting five or more places from the formed body having the communicating voids. The arithmetic average value thus obtained is taken as the density of the molded body having the communicating voids.
（熱可塑性樹脂発泡粒子７）
連通した空隙を有する成形体（連通空隙保有成形体６）を構成している熱可塑性樹脂発泡粒子７は、図５Ａに示すように、貫通孔８を有して形成されていることが好ましく、熱可塑性樹脂発泡粒子７は中空状に形成されていることが好ましい。図５Ａの例では、熱可塑性樹脂発泡粒子７は断面円形状の貫通孔８を有して、円筒形状に形成されている。ただし、このことは、熱可塑性樹脂発泡粒子７の形状を限定するものではなく、例えば、熱可塑性樹脂発泡粒子７は、円柱、楕円柱、角柱等の柱状発泡粒子の柱の上下方向を貫通する筒孔を少なくとも有する形状のものであることが好ましい。上記形状の中でも、製造安定性の観点からは、円筒状の発泡粒子が好ましい。
(Thermoplastic resin expanded particles 7)
As shown in FIG. 5A, the thermoplastic resin foam particles 7 constituting the molded body having the communicating voids (communication void-containing molded body 6) are preferably formed with through-holes 8, The thermoplastic resin expanded particles 7 are preferably formed in a hollow shape. In the example of FIG. 5A, the thermoplastic resin foamed particle 7 has a through-hole 8 having a circular cross section and is formed in a cylindrical shape. However, this does not limit the shape of the thermoplastic resin foamed particles 7. For example, the thermoplastic resin foamed particles 7 penetrate through the columns of columnar foamed particles such as a cylinder, an elliptical column, and a prism. A shape having at least a cylindrical hole is preferred. Among the above shapes, cylindrical expanded particles are preferable from the viewpoint of production stability.
（熱可塑性樹脂）
熱可塑性樹脂発泡粒子７を構成する基材樹脂となる熱可塑性樹脂としては、具体的には、ポリエチレン系樹脂、エチレン−酢酸ビニル共重合体、ポリプロピレン系樹脂、スチレン改質ポリオレフィンなどのオレフィン系樹脂、ポリスチレン、ブタジエン変性ポリスチレン（耐衝撃性ポリスチレン）、スチレン−メタクリル酸メチル共重合体、スチレン−アクリロニトリル共重合体などのスチレン系樹脂、ポリメタクリル酸メチルなどのアクリル系樹脂等が、採用されてよい。これらの中でも、強度や耐衝撃性の観点からはポリオレフィン系樹脂が好適である。
(Thermoplastic resin)
Specific examples of the thermoplastic resin used as the base resin constituting the thermoplastic resin expanded particles 7 include olefin resins such as polyethylene resin, ethylene-vinyl acetate copolymer, polypropylene resin, and styrene-modified polyolefin. Styrene resins such as polystyrene, butadiene-modified polystyrene (impact polystyrene), styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, and acrylic resins such as polymethyl methacrylate may be employed. . Among these, polyolefin resins are preferable from the viewpoint of strength and impact resistance.
さらにポリオレフィン系樹脂の中でも、ポリプロピレン系樹脂が好ましい。上記したポリプロピレン系樹脂としては、例えば、プロピレン単独重合体、プロピレンと他のコモノマーとの共重合体、あるいはこれらの混合物が挙げられる。プロピレンと他のコモノマーとの共重合体としては、例えば、プロピレン−エチレン共重合体、プロピレン−エチレン共重合体、プロピレン−エチレン−ブテン共重合体などが例示される。 Furthermore, among polyolefin resins, polypropylene resins are preferable. Examples of the polypropylene resin include a propylene homopolymer, a copolymer of propylene and another comonomer, or a mixture thereof. Examples of the copolymer of propylene and another comonomer include a propylene-ethylene copolymer, a propylene-ethylene copolymer, a propylene-ethylene-butene copolymer, and the like.
（貫通孔８）
貫通孔８は、図１，図５Ａ，図５Ｂの例では熱可塑性樹脂発泡粒子７の筒軸方向を法線とする面で熱可塑性樹脂発泡粒子７を切断した状態を想定した場合に認められる断面輪郭形状を円形状に形成されているが、楕円形状、多角形状など、その断面輪郭形状は特に限定されるものではない。
(Through hole 8)
The through holes 8 are recognized in the example of FIGS. 1, 5A, and 5B when assuming a state in which the thermoplastic resin foam particles 7 are cut along a plane whose normal is the cylindrical axis direction of the thermoplastic resin foam particles 7. Although the cross-sectional contour shape is formed in a circular shape, the cross-sectional contour shape such as an elliptical shape or a polygonal shape is not particularly limited.
熱可塑性樹脂発泡粒子成形体の状態で貫通孔８の直径は、１ｍｍ以上７ｍｍ以下であることが好ましい。貫通孔８の直径は、成形体断面写真における、発泡粒子に形成された貫通孔８の断面輪郭の平均径（貫通孔平均径）（図５Ａの例において符号Ｒで示す）であるものとする。貫通孔８の直径が上記範囲内であれば、吸音性能に優れた連通空隙保有成形体６を容易に得ることができる。なお、上記貫通孔８の直径は、成形体の断面写真を撮影し、その断面写真における貫通孔の直径を測定して算出することができる。上記観点から、貫通孔の直径は、１．１ｍｍ〜５ｍｍの範囲にあることがより好ましい。 It is preferable that the diameter of the through-hole 8 is 1 mm or more and 7 mm or less in the state of the thermoplastic resin foam particle molded body. The diameter of the through-hole 8 is the average diameter (through-hole average diameter) of the cross-sectional contour of the through-hole 8 formed in the foamed particle (indicated by the symbol R in the example of FIG. 5A) in the cross-sectional photograph of the molded body. . If the diameter of the through-hole 8 is within the above range, the communicating void-containing molded body 6 having excellent sound absorption performance can be easily obtained. The diameter of the through-hole 8 can be calculated by taking a cross-sectional photograph of the molded body and measuring the diameter of the through-hole in the cross-sectional photograph. From the above viewpoint, the diameter of the through hole is more preferably in the range of 1.1 mm to 5 mm.
さらに、熱可塑性樹脂発泡粒子７は、図５Ｂに示すように、筒状のポリオレフィン系樹脂発泡芯層９とその発泡芯層９を被覆するポリオレフィン系樹脂被覆層１０（単に、被覆層１０という場合がある。）とからなる多層構造を有するものであることが好ましい。この場合、発泡芯層９が、発泡した状態とされて発泡層をなしており、被覆層１０は、実質的に非発泡の状態とされた層である樹脂被覆層をなしていることが好ましい。なお、実質的にとは、気泡が全く存在しないもの（樹脂粒子を発泡させる際に一旦形成された気泡が溶融破壊されて気泡が消滅したものも包含する。）のみならず、得られる発泡粒子成形体の機械的強度に影響しない範囲で、ごく微小な気泡が僅かに存在するものも包含される。さらに図５Ｂに示すような熱可塑性樹脂発泡粒子においては、発泡芯層９に中空状の貫通孔８が形成されている。 Further, as shown in FIG. 5B, the thermoplastic resin foamed particles 7 include a cylindrical polyolefin resin foam core layer 9 and a polyolefin resin cover layer 10 that covers the foam core layer 9 (simply referred to as a cover layer 10). It is preferable to have a multilayer structure consisting of In this case, it is preferable that the foam core layer 9 is in a foamed state to form a foam layer, and the coating layer 10 is a resin coating layer that is a substantially non-foamed layer. . The term “substantially” means that there are no bubbles at all (including those in which bubbles once formed when the resin particles are foamed are melted and destroyed, and the bubbles disappear). In the range that does not affect the mechanical strength of the molded body, those in which a very small amount of bubbles are present are also included. Further, in the thermoplastic resin foam particles as shown in FIG. 5B, hollow through-holes 8 are formed in the foam core layer 9.
また、発泡芯層９を構成する樹脂と被覆層１０を構成する樹脂は熱可塑性樹脂であれば特に限定されず、例えば物性を同じくする樹脂であってもよいが、融点の異なる樹脂であることが好ましい。特に、熱可塑性樹脂発泡粒子７の被覆層１０を構成する樹脂は、発泡芯層９を構成する樹脂よりも低融点の樹脂であることが好適である。上記のような多層構造の発泡粒子を用いて型内成形を行い、連通した空隙を有する成形体（連通空隙保有成形体６）を得た場合、後述するように、連通した空隙を有する成形体全体の空隙率や表層部分の空隙率を制御することが容易となり、物品収納部材１の高周波音域での吸音特性を向上させることが容易となる。 The resin constituting the foam core layer 9 and the resin constituting the coating layer 10 are not particularly limited as long as they are thermoplastic resins. For example, resins having the same physical properties may be used, but resins having different melting points. Is preferred. In particular, the resin constituting the covering layer 10 of the thermoplastic resin foam particles 7 is preferably a resin having a lower melting point than the resin constituting the foam core layer 9. When molding is performed using the foamed particles having the multilayer structure as described above to obtain a molded body having continuous voids (molded void-containing molded body 6), a molded body having continuous voids as described later. It becomes easy to control the overall porosity and the porosity of the surface layer portion, and it is easy to improve the sound absorption characteristics of the article storage member 1 in the high frequency sound range.
（連通した空隙を有する成形体の表層部分の空隙率）
連通空隙保有成形体６において、表層部分の空隙率ａが１５％以上である。連通空隙保有成形体６の表層部分の空隙率が１５％以上であることで、物品収納部材１の吸音性能を向上させることができるという効果が得られる。上記観点から、連通空隙保有成形体６の表層部分の空隙率ａ％は、１８％以上５０％以下であることが好ましく、２０％以上４５％以下であることがさらに好ましい。なお上記のような表層部分の空隙率を有する、連通した空隙を有する発泡粒子成形体は、例えば融着性が改善された多層構造の発泡粒子を用いると、容易に製造することができる。
(Porosity of the surface layer portion of the molded body having continuous voids)
In the communicating void-containing molded body 6, the porosity a of the surface layer portion is 15% or more. The effect that the sound absorption performance of the article storage member 1 can be improved is obtained when the porosity of the surface layer portion of the communicating void-containing molded body 6 is 15% or more. From the above viewpoint, the porosity a% of the surface layer portion of the communicating void-containing molded body 6 is preferably 18% or more and 50% or less, and more preferably 20% or more and 45% or less. In addition, the foamed particle molded body having continuous voids having the porosity of the surface layer portion as described above can be easily produced by using, for example, foamed particles having a multilayer structure with improved fusing property.
（連通した空隙を有する成形体の表層部分の空隙率（％）と成形体内部の空隙率（％）の差）
さらに、前記成形体６においては、成形体の表層部分の空隙率（表層空隙率）（％）と成形体の内部の空隙率（内部空隙率と呼ぶことがある）（％）の差値である空隙率差（％）に関してみるに、表層部分の空隙率ａ（％）が内部空隙率ｂ（％）よりも大きい、または表層部分の空隙率ａ（％）と内部空隙率ｂ（％）が等しいことが、吸音性の観点からは好ましく、表層空隙率ａ（％）が内部空隙率ｂ（％）よりも大きいことがさらに好ましい。
(Difference between the porosity (%) of the surface layer portion of the molded body having continuous voids and the porosity (%) inside the molded body)
Further, in the molded body 6, the difference between the porosity of the surface layer portion (surface layer porosity) (%) and the internal porosity of the molded body (sometimes referred to as internal porosity) (%). Regarding a certain porosity difference (%), the porosity a (%) of the surface layer portion is larger than the internal porosity b (%), or the porosity a (%) of the surface layer portion and the internal porosity b (%) Are equal from the viewpoint of sound absorption, and it is more preferable that the surface layer porosity a (%) is larger than the internal porosity b (%).
ここに、成形体の表層部分とは、連通した空隙を有する発泡粒子成形体の最小厚みに対して、成形体の表面からの深さが該最小厚みの２０％以下であることを満たす部分を示すものとする。また、成形体の内部は、表層部分を除いた部分を示すものとする。 Here, the surface layer portion of the molded body is a portion satisfying that the depth from the surface of the molded body is 20% or less of the minimum thickness with respect to the minimum thickness of the foamed particle molded body having a continuous void. Shall be shown. Moreover, the inside of a molded object shall show the part except a surface layer part.
なお、表層部分の空隙率ａは、連通した空隙を有する発泡粒子成形体の断面写真を撮影し、その該当部分の断面写真から、空隙部分の面積と気泡膜（樹脂）部分の面積を算出し、その面積比率（面積％）として求めることができる。また、成形体内部の空隙率ｂは、成形体の断面写真を撮影し、その成形体表面から表層部分を除いた断面写真から、空隙部分の面積と気泡膜（樹脂）部分の面積を算出し、その面積比率（面積％）として求めることができる。 Note that the porosity a of the surface layer portion is obtained by taking a cross-sectional photograph of a foamed particle molded body having continuous voids, and calculating the area of the void portion and the area of the bubble membrane (resin) portion from the cross-sectional photograph of the corresponding portion. The area ratio (area%) can be obtained. Further, the porosity b inside the molded body is obtained by taking a cross-sectional photograph of the molded body and calculating the area of the void portion and the area of the bubble membrane (resin) portion from the cross-sectional photograph obtained by removing the surface layer portion from the surface of the molded body. The area ratio (area%) can be obtained.
（成形体全体の空隙率）
前記連通した空隙を有する成形体６は、成形体全体の空隙率が１５％以上５０％以下である。空隙率が１５％以上であることで、吸音性能に優れた成形体６となり物品収納部材１の吸音性能を向上させることができるという効果が得られる。また、空隙率が５０％以下であることで、音の透過が抑制され、吸音効率に優れた成形体６となる。こうした効果をより向上させる観点では、成形体６の空隙率は、２０％以上４０％以下がより好ましい。なお、上記のような空隙率を有する成形体は、貫通孔を有する発泡粒子を型内成形することによって、容易に得ることができる。
(Void ratio of the entire molded body)
The molded body 6 having the communicating voids has a porosity of 15% or more and 50% or less of the entire molded body. When the porosity is 15% or more, the molded body 6 having excellent sound absorption performance is obtained, and the effect that the sound absorption performance of the article storage member 1 can be improved is obtained. Further, when the porosity is 50% or less, the sound transmission is suppressed and the molded body 6 is excellent in sound absorption efficiency. From the viewpoint of further improving these effects, the porosity of the molded body 6 is more preferably 20% or more and 40% or less. In addition, the molded object which has the above void ratios can be easily obtained by carrying out in-mold shaping | molding of the foamed particle which has a through-hole.
空隙率は、次のようにして特定される。前記連通した空隙を有する成形体６から、複数個所の測定対象箇所を選択し、各測定対象箇所から厚みを成形体の厚みとしつつ所定の縦横寸法（例えば、縦２０ｍｍ×横２０ｍｍの寸法）のカットサンプルを切り出す。なお、上記カットサンプルは表層部と内部を含有する。該カットサンプルのそれぞれについて、カットサンプル外径寸法から体積Ｈ（ｃｍ３）を算出し、カットサンプルの空隙部を除いた体積Ｉ（ｃｍ３）を測定する。体積Ｉは、カットサンプルをアルコール中に沈めた時の、体積の増量分の値として求めることができる。このとき、アルコールとしては、例えばエタノールなどを用いることができる。そして、Ｈの値とＩの値に基づき、下記（式１）により空隙率を体積比率として算出する（体積％）。それぞれのカットサンプルについて算出された空隙率の値を算術平均し、それを空隙率とする。なお、測定対象箇所については、例えば上記した成形体６の密度を測定する際における測定点の選択方法と同様の方法を用いて選択することができる。 The porosity is specified as follows. A plurality of measurement target positions are selected from the molded body 6 having the communicating voids, and a predetermined vertical and horizontal dimension (for example, a dimension of 20 mm in length × 20 mm in width) is set while making the thickness from each measurement target position the thickness of the molded body. Cut out the cut sample. In addition, the said cut sample contains a surface layer part and the inside. For each cut sample, the volume H (cm 3 ) is calculated from the cut sample outer diameter, and the volume I (cm 3 ) of the cut sample excluding the voids is measured. The volume I can be determined as a value for an increase in volume when the cut sample is submerged in alcohol. At this time, as alcohol, ethanol etc. can be used, for example. And based on the value of H and the value of I, the porosity is calculated as a volume ratio by the following (Formula 1) (volume%). The porosity value calculated for each cut sample is arithmetically averaged and used as the porosity. In addition, about a measurement object location, it can select using the method similar to the selection method of the measurement point at the time of measuring the density of the above-mentioned molded object 6, for example.
（気泡膜厚）
前記連通した空隙を有する成形体６の気泡膜厚は５μｍ以下であることが好ましい。該成形体６の気泡膜厚が５μｍ以下であれば、高周波領域での吸音特性の向上効果がさらに見られる。気泡膜厚がより薄くなるほど、高周波音との相互作用がより顕著となり、吸音効果が向上すると考えられる。上記観点からは、連通した空隙を有する成形体６の気泡膜厚は、４μｍ以下が好ましく、３μｍ以下がさらに好ましい。なお、気泡膜の構造を維持し、物品収納部材としての強度を維持する観点からは、気泡膜厚は０．５μｍ以上であることが好ましい。
(Bubble film thickness)
The cell thickness of the molded body 6 having the communicating voids is preferably 5 μm or less. If the cell thickness of the molded body 6 is 5 μm or less, the effect of improving the sound absorption characteristics in the high frequency region is further seen. It is considered that as the bubble film thickness becomes thinner, the interaction with the high frequency sound becomes more remarkable and the sound absorbing effect is improved. From the above viewpoint, the cell thickness of the molded body 6 having the communicating voids is preferably 4 μm or less, and more preferably 3 μm or less. In addition, from the viewpoint of maintaining the structure of the bubble film and maintaining the strength as the article storage member, the bubble film thickness is preferably 0.5 μm or more.
気泡膜厚みＴｍは、前記連通した空隙を有する成形体６の平均気泡径ｄと、下記（式２）から誘導されうる下記（式３）とを用いて算出される。なお、下記（式２）は、「プラスチックフォームハンドブック」（発行所：日刊工業新聞社、昭和４８年２月２８日（１９７３年２月２８日）発行）、２２２頁目の「１．３．２の項」の記載に基づく。 The bubble film thickness Tm is calculated using the average bubble diameter d of the molded body 6 having the communicating voids and the following (Expression 3) that can be derived from the following (Expression 2). The following (Formula 2) is “Plastic Foam Handbook” (published by Nikkan Kogyo Shimbun, published on February 28, 1973 (February 28, 1973)), “1.3. Based on the description in Section 2.
上記（式２）中、ＶＳは基材樹脂の容積分率、ρｆは成形体６の見かけ密度（ｇ／ｃｍ３）、ρｓは基材樹脂の密度（ｇ／ｃｍ３）、ρｇは成形体の気泡内のガス密度（ｇ／ｃｍ３）、ｄは平均気泡径（μｍ）、Ｔｍは平均気泡膜厚み（μｍ）である。なお、平均気泡径は次のように測定される。サンプルの切断面を走査型電子顕微鏡にて写真を撮影する。得られた断面写真において、切断面の中心付近から八方向に等間隔に直線を引き、その直線と交わる気泡の数を全てカウントし、該直線の合計長さをカウントされた気泡数で除して得られた値を気泡径とする。なお、測定対象箇所については、例えば上記した成形体６の密度を測定する際における測定点の選択方法と同様の方法を用いて選択し、各測定対象箇所から厚みを成形体の厚みとしつつ所定の縦横寸法（例えば、縦２０ｍｍ×横２０ｍｍの寸法）のカットサンプルとする。 Above in (Equation 2), V S is the volume fraction of the base resin, the apparent density (g / cm 3) of ρf molded body 6, .rho.s the density of the base resin (g / cm 3), ρg molding The gas density (g / cm 3 ) in the bubbles of the body, d is the average bubble diameter (μm), and Tm is the average bubble film thickness (μm). The average bubble diameter is measured as follows. A photograph of the cut surface of the sample is taken with a scanning electron microscope. In the obtained cross-sectional photograph, straight lines are drawn at equal intervals in the eight directions from the vicinity of the center of the cut surface, the number of bubbles crossing the straight line is counted, and the total length of the straight lines is divided by the counted number of bubbles. The value obtained in this way is taken as the bubble diameter. In addition, about a measurement object location, it selects using the method similar to the selection method of the measurement point at the time of measuring the density of the above-mentioned molded object 6, for example, and it is predetermined, making thickness from each measurement object location into the thickness of a molded object A cut sample having a vertical and horizontal dimension (for example, a dimension of 20 mm in length × 20 mm in width).
発泡成形体においては、ρｆ＞＞ρｇ且つρｓ＞＞ρｇであることから、上記（式２）中、Ｖｓ＝ρｆ／ρｓと近似できる。そこで、この近似と（式２）に基づき、平均気泡膜厚みＴｍ（μｍ）は、下記（式３）から算出することができる。 In the foamed molded product, since ρf >> ρg and ρs >> ρg, Vs = ρf / ρs can be approximated in the above (Equation 2). Therefore, based on this approximation and (Expression 2), the average bubble film thickness Tm (μm) can be calculated from the following (Expression 3).
上記（式３）中、Ｘは、ρｓ／ρｆである。 In the above (Formula 3), X is ρs / ρf.
なお、物品収納部材１においては、前記連通した空隙を有する成形体６の密度αとその他の部分（成形体６を除く部分）を形成する成形体の密度βとの差の絶対値が、０．１ｇ／ｃｍ３以下であることが好ましい。前記密度αと密度βとの差の絶対値が０．１ｇ／ｃｍ３以下の範囲にあることで、物品収納部材１として、その全体強度を十分に保持されたものを得ることがより容易となる。 In the article storage member 1, the absolute value of the difference between the density α of the molded body 6 having the communicating voids and the density β of the molded body forming other parts (portions excluding the molded body 6) is 0. .1 g / cm 3 or less is preferable. When the absolute value of the difference between the density α and the density β is in the range of 0.1 g / cm 3 or less, it is easier to obtain the article storage member 1 having sufficiently maintained the overall strength. Become.
（立ち上がり部）
図１の例に示すように、物品収納部材１においては、底面部２２から起立した部分で構成される立ち上がり部が形成されてよい。図１の例では、立ち上がり部は、側壁４と仕切り壁５でなる部分として構成される。立ち上がり部は、底面部２２から連続一体的に構成されてよく、また、底面部２２を形成する連通した空隙を有する成形体とは別に成形された部材を、所定位置に取り付け固定して構成されてもよい。立ち上がり部に対応する部分を形成する成形体は、発泡粒子型内成形体であることが好ましく、例えば、株式会社ジェイエスピー製のピーブロック（商標）のような市販されている発泡体などが挙げられる。なお、立ち上がり部を別体として構成し、熱可塑性樹脂発泡粒子成形体で形成することにより、物品収納部材１の意匠性を向上させることができる。また、底面部２２の上方側を、熱可塑性樹脂発泡粒子成形体で形成することにより、物品収納部材１の意匠性はさらに向上する。
(Rising part)
As shown in the example of FIG. 1, in the article storage member 1, a rising portion configured by a portion rising from the bottom surface portion 22 may be formed. In the example of FIG. 1, the rising portion is configured as a portion including a side wall 4 and a partition wall 5. The rising portion may be configured continuously and integrally from the bottom surface portion 22, and is configured by attaching and fixing a member formed separately from a molded body having a continuous gap forming the bottom surface portion 22 at a predetermined position. May be. The molded body that forms the portion corresponding to the rising portion is preferably a foamed particle-in-mold molded body, such as a commercially available foam such as P-Block (trademark) manufactured by GS Corporation. It is done. In addition, the design property of the article | item storage member 1 can be improved by comprising a standup | rising part as a different body and forming with a thermoplastic resin foam particle molded object. Moreover, the design property of the article | item storage member 1 further improves by forming the upper side of the bottom face part 22 with a thermoplastic resin foam particle molding.
（高周波音での吸音性）
本発明の物品収納部材１は、熱可塑性樹脂発泡粒子成形体で構成され、少なくとも下面２側が連通した空隙を有する特定の成形体６で形成された吸音層２３を有することで、強度と耐衝撃性を有しつつ軽量性に優れ、且つ、高周波音域での吸音性に優れる。このため、この物品収納部材１を設けた自動車においては、高周波音域の音漏れの問題が抑制される。また、物品収納部材１に別体にて準備された吸音材を設置せずとも十分な吸音が可能となり、自動車においてトランクルームとして活用できるスペースをできるだけ広く確保することが容易となる。
(Sound absorption with high frequency sound)
The article storage member 1 of the present invention includes a sound absorbing layer 23 formed of a thermoplastic resin foamed particle molded body and formed of a specific molded body 6 having at least a gap communicating with the lower surface 2 side, thereby providing strength and impact resistance. In addition, it has excellent lightness and sound absorption in a high frequency sound range. For this reason, in the automobile provided with the article storage member 1, the problem of sound leakage in the high frequency sound range is suppressed. Further, sufficient sound absorption is possible without installing a separate sound absorbing material in the article storage member 1, and it is easy to secure as much space as possible as a trunk room in an automobile.
なお、物品収納部材１について、吸音性は、物品収納部材１の内部に対象となる音が侵入し拡散することにより、音のエネルギーが、振動を伴った熱エネルギーに変換され、反射する音の量が小さくなる性質を示すためであると考えられる。そして、前記連通した空隙を有する成形体６のように、表層部分の空隙率が従来よりも高く、１５％以上であるとともに、成形体全体の空隙率が１５％以上５０％以下であるという特定の空隙構造を有する成形体を用いて、吸音層２３が形成されることにより、物品収納部材１は高周波音の吸音に特に優れるものとなる。特に、このような空隙構造を有する発泡粒子成形体は、後述する特定の発泡粒子を型内成形することにより、容易に得ることができる。 Note that the sound absorption of the article storage member 1 is such that the sound energy is converted into thermal energy accompanied by vibration and reflected when the target sound enters and diffuses inside the article storage member 1. This is considered to be due to the property of reducing the amount. And like the molded object 6 which has the said communicating space | gap, while the porosity of a surface layer part is higher than before, it is 15% or more, and the porosity of the whole molded object is 15% or more and 50% or less specification By forming the sound absorbing layer 23 using the molded body having the void structure, the article storage member 1 is particularly excellent in sound absorption of high frequency sound. In particular, the foamed particle molded body having such a void structure can be easily obtained by in-mold molding specific foamed particles described later.
（吸音性の特定）
物品収納部材１の吸音性の程度は、例えば、ＪＩＳ Ａ１４０５−２に準拠した音響管による吸音率の測定により得られた値にて評価できる。吸音率の測定は、物品収納部材１から選択された測定対象箇所（吸音層２３を形成する連通した空隙を有する熱可塑性樹脂発泡粒子成形体）から、垂直入射吸音率測定器を用い、音響管直径１６ｍｍの音響管を使用し、２〜１０ｋＨｚの吸音率を測定し、周波数５．５ｋＨｚ、７．８ｋＨｚ、１０ＫＨｚにおける吸音率を、ｎ数＝３の平均値として算出することができる。垂直入射吸音率測定器としては、例えばＡＣＩＭＳ（株式会社神戸製鋼所製）を使用することができる。
(Specification of sound absorption)
The degree of sound absorption of the article storage member 1 can be evaluated by, for example, a value obtained by measuring the sound absorption coefficient with an acoustic tube in accordance with JIS A1405-2. The sound absorption coefficient is measured by using a normal incident sound absorption coefficient measuring device from a measurement target portion selected from the article storage member 1 (a thermoplastic resin foam particle molded body having a continuous void forming the sound absorption layer 23). An acoustic tube having a diameter of 16 mm is used, a sound absorption coefficient of 2 to 10 kHz is measured, and the sound absorption coefficient at frequencies of 5.5 kHz, 7.8 kHz, and 10 KHz can be calculated as an average value of n number = 3. As the normal incident sound absorption coefficient measuring device, for example, ACIMS (manufactured by Kobe Steel, Ltd.) can be used.
（５０％歪時圧縮応力）
５０％歪時圧縮応力は、例えば次のように測定することができる。すなわち、上記吸音性の特定の場合と同様に物品収納部材１から選択された測定対象箇所から、例えば縦５０ｍｍ×横５０ｍｍ×厚み２５ｍｍのサイズの試験片を切り出す。その試験片を用い、ＪＩＳ Ｋ７２２０：２００６に準拠し、５０％歪み時の圧縮応力を測定することができ、強度や耐衝撃性を評価できる。５０％歪時の圧縮応力は、０．０８〜０．５ＭＰａであることが好ましく、０．１〜０．３ＭＰａであることがより好ましい。５０％歪時の圧縮応力が低いほど、柔軟性に優れるものとなり、耐衝撃性に優れる成形体となる。
(Compressive stress at 50% strain)
The 50% strain compressive stress can be measured, for example, as follows. That is, a test piece having a size of, for example, 50 mm in length, 50 mm in width, and 25 mm in thickness is cut out from a measurement target portion selected from the article storage member 1 in the same manner as in the specific case of sound absorption. Using the test piece, the compressive stress at 50% strain can be measured according to JIS K7220: 2006, and the strength and impact resistance can be evaluated. The compressive stress at 50% strain is preferably 0.08 to 0.5 MPa, and more preferably 0.1 to 0.3 MPa. The lower the compressive stress at the time of 50% strain, the better the flexibility and the molded article with excellent impact resistance.
［物品収納部材１の製造方法］
物品収納部材１は次のように製造することができる。ここでは、物品収納部材１が、底面部２２に対応する部分と、側壁４と仕切り壁５のいずれについても、連通した空隙を有する熱可塑性樹脂発泡粒子成形体で構成され、且つ、図２に示す形状である場合を例として、その製造方法の一例について説明する。
[Manufacturing method of article storage member 1]
The article storage member 1 can be manufactured as follows. Here, the article storage member 1 is formed of a thermoplastic resin foamed particle molded body having a communicating space for both the portion corresponding to the bottom surface portion 22 and the side wall 4 and the partition wall 5, and FIG. Taking the case of the shape shown as an example, an example of the manufacturing method will be described.
（熱可塑性樹脂発泡粒子７の製造）
次に、本発明に用いられる発泡粒子の製造方法について説明する。ここでは、発泡粒子が多層構造である場合を例として、その発泡粒子の製造方法の例について示す。発泡粒子は、ポリオレフィン系樹脂で構成される非発泡状態の芯層と、その芯層を構成するポリオレフィン系樹脂の融点Ｔｃ（℃）より低い融点Ｔｓ（℃）のポリオレフィン系樹脂で構成される非発泡状態の外側被覆層とからなる多層樹脂粒子を、後述する方法により発泡させることにより得ることができる。
(Manufacture of thermoplastic resin expanded particles 7)
Next, the manufacturing method of the expanded particle used for this invention is demonstrated. Here, taking as an example the case where the expanded particles have a multilayer structure, an example of a method for producing the expanded particles will be described. The expanded particles are a non-foamed core layer composed of a polyolefin resin, and a non-foamed core layer composed of a polyolefin resin having a melting point Ts (° C.) lower than the melting point Tc (° C.) of the polyolefin resin constituting the core layer. Multilayer resin particles composed of a foamed outer coating layer can be obtained by foaming by the method described later.
多層樹脂粒子は、例えば、次のようにして得られる。芯層形成用押出機と被覆層形成用押出機の２台の押出機を共押出ダイに連結し、芯層形成用押出機には、芯層形成用のポリオレフィン系樹脂と、必要に応じて供給される添加剤とを溶融混練し、一方の被覆層形成用押出機には被覆層形成用のポリオレフィン系樹脂と、必要に応じて供給される添加剤とを溶融混練する。さらに、それぞれの溶融混練物を前記ダイ内で合流させ、非発泡状態の筒状の芯層と、芯層の外側表面を被覆する非発泡状態の外側被覆層とからなる鞘芯型の複合体を形成する。そして、押出機先端に付設された口金の細孔から該複合体をストランド状に押出し、ペレタイザーで粒子の重量が所定の重量となるようにストランド状の押出成形体を切断することにより、筒状のポリオレフィン系樹脂からなる芯層とこれを被覆するポリオレフィン系樹脂からなる外側被覆層とからなる多層樹脂粒子を得ることができる。 Multilayer resin particles are obtained, for example, as follows. Two extruders, a core layer forming extruder and a coating layer forming extruder, are connected to a coextrusion die, and the core layer forming extruder includes a polyolefin resin for forming the core layer, and if necessary. The supplied additive is melt-kneaded, and one coating layer forming extruder is melt-kneaded with the polyolefin resin for forming the coating layer and, if necessary, the additive to be supplied. Further, a sheath-core type composite comprising a non-foamed cylindrical core layer and a non-foamed outer coating layer covering the outer surface of the core layer by joining the respective melt-kneaded materials in the die. Form. Then, the composite is extruded into a strand shape from the pores of the die attached to the tip of the extruder, and the strand-shaped extruded product is cut with a pelletizer so that the weight of the particles becomes a predetermined weight. It is possible to obtain multi-layer resin particles comprising a core layer made of a polyolefin resin and an outer coating layer made of a polyolefin resin covering the core layer.
本発明に用いられる多層発泡粒子は、上記した多層樹脂粒子を用いて例えば次に示すような分散媒放出発泡方法などの発泡方法を実施することにより、得ることができる。 The multilayer foamed particles used in the present invention can be obtained by carrying out a foaming method such as the following dispersion medium release foaming method using the multilayer resin particles described above.
（分散媒放出発泡方法）
分散媒放出発泡方法においては、非発泡状態の芯層と外側被覆層からなる多層樹脂粒子を、オートクレーブ等の密閉容器内において分散媒に分散させ芯層を構成するポリオレフィン系樹脂の軟化温度以上の温度に加熱し、発泡剤を圧入して多層樹脂粒子に発泡剤を含浸させる。次に、密閉容器内の圧力を発泡剤の蒸気圧以上の圧力に保持しながら、密閉容器内の一端を開放し、多層樹脂粒子と分散媒とを同時に容器内よりも低圧の雰囲気下に放出する。このとき、多層樹脂粒子が発泡する。発泡により、少なくとも芯層が発泡状態となって発泡芯層をなす。こうして、発泡粒子を得ることができる。なお、分散媒放出発泡方法においては、分散媒は、通常、水系媒体が使用される。
(Dispersion medium release foaming method)
In the dispersion medium releasing foaming method, multilayer resin particles composed of a non-foamed core layer and an outer coating layer are dispersed in a dispersion medium in an airtight container such as an autoclave, and the temperature exceeds the softening temperature of the polyolefin resin constituting the core layer. Heat to temperature and press-fit a foaming agent to impregnate the multilayer resin particles with the foaming agent. Next, while maintaining the pressure inside the closed container at a pressure equal to or higher than the vapor pressure of the foaming agent, one end inside the closed container is opened, and the multilayer resin particles and the dispersion medium are simultaneously released into a lower pressure atmosphere than inside the container. To do. At this time, the multilayer resin particles are foamed. By foaming, at least the core layer is in a foamed state to form a foamed core layer. Thus, expanded particles can be obtained. In the dispersion medium releasing foaming method, an aqueous medium is usually used as the dispersion medium.
分散媒放出発泡方法においては、容器内で多層樹脂粒子が加熱された場合に多層樹脂粒子同士が容器内で互いに融着しないように、分散媒体中に分散剤を添加することが好ましい。分散剤は、多層樹脂粒子１００重量部当り、０．００１重量部〜５重量部程度使用されることが好ましい。 In the dispersion medium releasing foaming method, it is preferable to add a dispersant to the dispersion medium so that the multilayer resin particles are not fused to each other in the container when the multilayer resin particles are heated in the container. The dispersant is preferably used in an amount of about 0.001 to 5 parts by weight per 100 parts by weight of the multilayer resin particles.
発泡剤としては、例えば、プロパン、ブタン、ヘキサン、ヘプタン等の脂肪族炭化水素類、シクロブタン、シクロヘキサン等の環式脂肪族炭化水素類、クロロフロロメタン、トリフロロメタン、１，２−ジフロロエタン、１，２，２，２−テトラフロロエタン、メチルクロライド、エチルクロライド、メチレンクロライド等のハロゲン化炭化水素などの有機系物理発泡剤や、窒素、酸素、空気、二酸化炭素、水といったいわゆる無機系物理発泡剤などといった各種の物理発泡剤が例示される。また有機系物理発泡剤と無機系物理発泡剤を併用することもできる。こうした各種物理発泡剤の中でも、窒素、酸素、空気、二酸化炭素、水からなる群から選択される１又は２以上の無機系物理発泡剤を主成分とするものが好適である。 Examples of the blowing agent include aliphatic hydrocarbons such as propane, butane, hexane, and heptane, cyclic aliphatic hydrocarbons such as cyclobutane and cyclohexane, chlorofluoromethane, trifluoromethane, 1,2-difluoroethane, 1 Organic physical foaming agents such as halogenated hydrocarbons such as 1,2,2,2-tetrafluoroethane, methyl chloride, ethyl chloride, and methylene chloride, and so-called inorganic physical foaming such as nitrogen, oxygen, air, carbon dioxide, and water Various physical foaming agents such as agents are exemplified. An organic physical foaming agent and an inorganic physical foaming agent can also be used in combination. Among these various physical foaming agents, those mainly composed of one or more inorganic physical foaming agents selected from the group consisting of nitrogen, oxygen, air, carbon dioxide, and water are suitable.
分散媒放出発泡方法における発泡剤の容器内への充填量は、使用する発泡剤の種類と発泡温度と得ようとする発泡粒子の見掛け密度に応じて適宜選択される。具体的には、例えば発泡剤として二酸化炭素を使用し、分散媒体として水を使用した場合、発泡開始直前の安定した状態にある密閉容器内の圧力、すなわち密閉容器内空間部の圧力（ゲージ圧）が、０．６〜６ＭＰａ（Ｇ）となるようにすることが好ましい。なお、一般的に、目的とする発泡粒子の見掛け密度が小さいほど密閉容器内空間部の圧力は高い値とすることが望ましく、目的とする発泡粒子の見掛け密度が大きいほど密閉容器内空間部の圧力は低い値とすることが望ましい。 The filling amount of the foaming agent in the dispersion medium releasing foaming method is appropriately selected according to the type of foaming agent used, the foaming temperature, and the apparent density of the foamed particles to be obtained. Specifically, for example, when carbon dioxide is used as a foaming agent and water is used as a dispersion medium, the pressure in the sealed container in a stable state immediately before the start of foaming, that is, the pressure in the space in the sealed container (gauge pressure) ) Is preferably 0.6 to 6 MPa (G). In general, the smaller the apparent density of the target foamed particles, the higher the pressure in the space inside the sealed container, and the higher the apparent density of the target foamed particles, the higher the pressure in the space inside the sealed container. It is desirable to set the pressure to a low value.
（熱可塑性樹脂発泡粒子成形体の成形）
一対の雄型と雌型を有して構成される金型を準備する。金型は、例えば物品収納部材１の形状に対応した型内形状を備えている。この金型内に熱可塑性樹脂発泡粒子７を充填して型内成形を実施することにより、熱可塑性樹脂発泡粒子成形体が形成される。そして、この熱可塑性樹脂発泡粒子成形体が物品収納部材１をなす。なお、作製された物品収納部材１を形成する熱可塑性樹脂発泡粒子成形体には上述したように連通した空隙が形成されている。ただし、ここに説明した作製方法の例では、物品収納部材１全体に連通した空隙が形成される。
(Molding of molded thermoplastic resin particles)
A mold having a pair of male mold and female mold is prepared. The mold has an in-mold shape corresponding to the shape of the article storage member 1, for example. By filling the mold with the thermoplastic resin foam particles 7 and carrying out in-mold molding, a thermoplastic resin foam particle molded body is formed. The thermoplastic resin expanded particle molded body forms the article storage member 1. Note that, as described above, the communicating voids are formed in the thermoplastic resin expanded particle molded body forming the manufactured article storage member 1. However, in the example of the manufacturing method described here, a void communicating with the entire article storage member 1 is formed.
（連通した空隙）
ここに、熱可塑性樹脂発泡粒子成形体に形成される連通した空隙は、（Ａ）可塑性樹脂発泡粒子７に形成された中空状の貫通孔８に由来する空隙や、（Ｂ）隣り合う可塑性樹脂発泡粒子７，７相互間の間隙に形成される空隙が連通して、熱可塑性樹脂発泡粒子成形体の一方面側から他方面側まで連通した状態で空隙が形成されている。
(Communication gap)
Here, the continuous voids formed in the thermoplastic resin foam particle molded body are (A) voids derived from the hollow through-holes 8 formed in the plastic resin foam particles 7, and (B) adjacent plastic resins. The voids are formed in a state where the voids formed in the gap between the expanded particles 7 and 7 communicate with each other and communicate from the one surface side to the other surface side of the thermoplastic resin foam particle molded body.
なお、熱可塑性樹脂発泡粒子７として、中空状の貫通孔８を有する発泡芯層９とその発泡芯層９の外周面を被覆する被覆層１０とで構成される多層構造を有し、且つ、発泡芯層９よりも低融点の樹脂で被覆層１０を構成した多層発泡粒子が用いられた場合、熱可塑性樹脂発泡粒子成形体の連通した空隙は、空隙全体のうち上記（Ａ）に示す空隙の占める割合が上記（Ｂ）に示す空隙の占める割合よりも大きくなった状態となる。このような空隙の状態の形成が、高周波音域での吸音特性を特に向上させると考えられる。 The thermoplastic resin foam particles 7 have a multilayer structure composed of a foam core layer 9 having a hollow through-hole 8 and a coating layer 10 covering the outer peripheral surface of the foam core layer 9, and When multi-layer expanded particles in which the coating layer 10 is made of a resin having a melting point lower than that of the expanded core layer 9 are used, the connected voids of the thermoplastic resin expanded particle molded body are voids shown in (A) above in the entire void. The ratio occupied by becomes larger than the ratio occupied by the voids shown in (B) above. It is considered that the formation of such a void state particularly improves the sound absorption characteristics in the high frequency sound range.
このような熱可塑性樹脂発泡粒子７においては、被覆層１０のほうが、発泡芯層９よりも低温で加熱融着しやすくなっていることから、発泡芯層９の２次発泡を抑制しつつも、熱可塑性樹脂発泡粒子７同士を融着することが可能である。したがって、熱可塑性樹脂発泡粒子７の貫通孔８の形状を２次発泡で不定形に変化させることを抑制しつつ、熱可塑性樹脂発泡粒子７を融着できることとなり、熱可塑性樹脂発泡粒子成形体の連通した空隙の均一性が向上するとともに、発泡粒子成形体表面の空隙率の低下が抑制される。したがって、物品収納部材１の吸音性を均一化させ、さらに高周波音域での吸音特性を向上させることが容易となる。また、２次発泡に頼らずに熱可塑性樹脂発泡粒子７を相互融着でき、熱可塑性樹脂発泡粒子成形体の連通した空隙の全体空隙率を高めることも容易となるので、高周波音域での吸音特性を向上させることができる。 In such a thermoplastic resin foamed particle 7, the coating layer 10 is easier to heat-fuse at a lower temperature than the foamed core layer 9, while suppressing secondary foaming of the foamed core layer 9. It is possible to fuse the thermoplastic resin expanded particles 7 together. Therefore, the thermoplastic resin foamed particles 7 can be fused while suppressing the shape of the through-holes 8 of the thermoplastic resin foamed particles 7 from being changed to an indeterminate shape by secondary foaming. The uniformity of the communicating voids is improved, and the decrease in the void ratio on the surface of the foamed particle molded body is suppressed. Therefore, it is easy to make the sound absorption property of the article storage member 1 uniform and further improve the sound absorption characteristics in the high frequency sound range. In addition, the thermoplastic resin foam particles 7 can be fused to each other without relying on secondary foaming, and it becomes easy to increase the overall porosity of the communicating pores of the thermoplastic resin foam particle molded body. Characteristics can be improved.
［物品収納部材１の使用］
物品収納部材１は、自動車用物品収納部材として使用可能であり、図３，図４に示すように、自動車１５において車室１８の後方側に通常位置するトランクルーム１９内に設置されて使用可能なものである。図３，図４は、物品収納部材１を設置した自動車１５の例を説明するための図面である。なお、この例に示す自動車１５は、電気モーターによる駆動の可能な自動車である。自動車１５には、物品収納部材１の下方側に電気モーター１６や減速機（図示せず）などを備えたパワーユニットが配置されている。なお符号１７は電気モーター１６の出力を制御するインバータである。
[Use of article storage member 1]
The article storage member 1 can be used as an article storage member for automobiles, and can be used by being installed in a trunk room 19 that is normally located on the rear side of the passenger compartment 18 in the automobile 15 as shown in FIGS. Is. 3 and 4 are drawings for explaining an example of the automobile 15 in which the article storage member 1 is installed. The automobile 15 shown in this example is an automobile that can be driven by an electric motor. In the automobile 15, a power unit including an electric motor 16 and a speed reducer (not shown) is disposed on the lower side of the article storage member 1. Reference numeral 17 denotes an inverter that controls the output of the electric motor 16.
このような自動車１５においては、物品収納部材１のうち電気モーター１６により近い位置にある下面側が、連通した空隙を有する成形体６で構成されている。そして、この成形体６は、高周波音域の吸音性に優れる。こうしたことから、自動車１５においては、パワーユニットから高周波音が発生したとしても、物品収納部材１にて高周波音が吸音されることになり、高周波音の発生源からトランクルーム１９側に音が漏れる虞が抑制され、さらに、座席シート２０の設けられている車室１８内に音が漏れる虞も抑制され、自動車１５の乗員に高周波音を感じさせる虞を抑制することができる。 In such an automobile 15, the lower surface side, which is closer to the electric motor 16 in the article storage member 1, is composed of a molded body 6 having a communicating gap. And this molded object 6 is excellent in the sound-absorbing property of a high frequency sound range. For this reason, in the automobile 15, even if high frequency sound is generated from the power unit, high frequency sound is absorbed by the article storage member 1, and there is a possibility that sound leaks from the high frequency sound generation source to the trunk room 19 side. In addition, the possibility of sound leaking into the passenger compartment 18 where the seat 20 is provided is also suppressed, and the possibility of causing the passenger of the automobile 15 to feel high-frequency sound can be suppressed.
次に、物品収納部材１について実施例を用いてより詳細に説明する。 Next, the article storage member 1 will be described in more detail using examples.
実施例１から８、比較例１から３
（発泡粒子の調製）
内径６５ｍｍの芯層形成用押出機および内径３０ｍｍの外側被覆層形成用押出機の出口側に多層ストランド形成用ダイが取付けられた押出機を用い、芯層を形成するためのポリオレフィン系樹脂、及び外側被覆層を形成するためのポリオレフィン系樹脂を、それぞれの押出機に供給し、溶融混練してそれぞれ溶融混練物とした。芯層を形成するポリオレフィン系樹脂、及び外側被覆層を形成するポリオレフィン系樹脂は、それぞれ発泡芯層、被覆層を構成することを予定された樹脂であり、それぞれを表１，表２に示す。なお表１，表２中、ＰＰはポリプロピレンを示し、ＰＥ／ＰＳは、ポリエチレンとポリスチレンの複合樹脂を示す。
Examples 1 to 8, Comparative Examples 1 to 3
(Preparation of expanded particles)
A polyolefin-based resin for forming a core layer using an extruder having a core layer forming extruder having an inner diameter of 65 mm and an extruder having a multi-layer strand forming die attached to the outlet side of an outer coating layer forming extruder having an inner diameter of 30 mm; and The polyolefin resin for forming the outer coating layer was supplied to each extruder and melt-kneaded to obtain melt-kneaded materials. The polyolefin-based resin forming the core layer and the polyolefin-based resin forming the outer coating layer are resins that are planned to form the foam core layer and the coating layer, respectively, and are shown in Tables 1 and 2, respectively. In Tables 1 and 2, PP represents polypropylene, and PE / PS represents a composite resin of polyethylene and polystyrene.
芯層を構成する樹脂、及び外側被覆層を構成する樹脂を用いてそれぞれに調製された溶融混練物は、多層ストランド形成用ダイに導入され、ダイ内で合流してダイ先端に取付けた口金の小孔から、円筒形状のストランドとして押出された（非発泡芯層の重量％：外側被覆層の重量％＝９５：５）。さらに押出されたストランドが水冷され、ペレタイザーで切断され乾燥されて円筒形状の多層樹脂粒子が得られた。多層樹脂粒子は、外側被覆層と非発泡状態の芯層の２層（鞘芯形状）に積層された構造を有しており、芯層に貫通孔を有した構造に形成される。 The melt-kneaded materials prepared respectively using the resin constituting the core layer and the resin constituting the outer coating layer are introduced into a die for forming a multi-layer strand, merged in the die, and attached to the tip of the die. From the small holes, it was extruded as a cylindrical strand (% by weight of the non-foamed core layer:% by weight of the outer coating layer = 95: 5). Further, the extruded strand was cooled with water, cut with a pelletizer and dried to obtain cylindrical multilayer resin particles. The multilayer resin particle has a structure in which two layers (sheath core shape) of an outer covering layer and a non-foamed core layer are laminated, and is formed in a structure having a through hole in the core layer.
なお、芯層を構成する樹脂については、気泡調整剤としてホウ酸亜鉛の含有量が１０００重量ｐｐｍとなるように、芯層を構成する樹脂を基材樹脂としたマスターバッチが調製されて、芯層形成用押出機に供給された。 As for the resin constituting the core layer, a master batch was prepared using the resin constituting the core layer as the base resin so that the content of zinc borate as the bubble regulator was 1000 ppm by weight. It was supplied to the layer forming extruder.
調製された多層樹脂粒子８００ｇと分散媒の水３Ｌを、容量５Ｌの密閉容器内に仕込み、多層樹脂粒子１００重量部に対する配合比で、分散剤としてカオリンを０．３重量部、界面活性剤（商品名：ネオゲン（商標）、第一工業製薬株式会社製、アルキルベンゼンスルホン酸ナトリウム）を０．４重量部（有効成分として）、及び硫酸アルミニウムを０．０１重量部が、それぞれ密閉容器内に添加された。次いで、密閉容器内に発泡剤として二酸化炭素を圧入し、密閉容器内の内容物を撹拌しながら表１、表２に示す発泡温度より５℃低い温度まで加熱昇温して、その温度を１５分間保持して高温ピーク熱量を調整した。その後、さらに表１、表２に示す発泡温度まで加熱昇温して再度１５分間保持した。しかる後、密閉容器内の内容物を大気圧下に水と共に放出した。このとき芯層は、発泡して発泡芯層をなし、外側被覆層は、発泡芯層の周面を被覆する被覆層をなした。こうして多層の発泡粒子を得た。得られた発泡粒子については、見掛け密度が測定された。測定方法は、既述した方法が用いられた。結果は表１、表２に示すとおりである。 The prepared multilayer resin particles (800 g) and dispersion medium water (3 L) were charged into a closed container with a capacity of 5 L, and the mixing ratio with respect to 100 parts by weight of the multilayer resin particles was 0.3 parts by weight of kaolin as a dispersant, a surfactant ( Product name: Neogen (trademark), Daiichi Kogyo Seiyaku Co., Ltd., sodium alkylbenzene sulfonate) 0.4 parts by weight (as an active ingredient) and 0.01 parts by weight of aluminum sulfate are added to the sealed container. It was done. Next, carbon dioxide is injected as a foaming agent into the sealed container, and the contents in the sealed container are heated to a temperature lower by 5 ° C. than the foaming temperatures shown in Tables 1 and 2 while stirring. The high temperature peak heat amount was adjusted by holding for a minute. Thereafter, the mixture was further heated to the foaming temperatures shown in Tables 1 and 2 and held again for 15 minutes. Thereafter, the contents in the sealed container were discharged together with water under atmospheric pressure. At this time, the core layer was foamed to form a foam core layer, and the outer coating layer was a coating layer covering the peripheral surface of the foam core layer. In this way, multi-layer expanded particles were obtained. The apparent density was measured for the obtained expanded particles. As the measurement method, the method described above was used. The results are as shown in Tables 1 and 2.
（物品収納部材の下面側を形成する成形体の調製）
雄型と雌型の一対の金型を準備した。金型としては、その内部空間を物品収納部材の形状にしたものが準備された。下面側の形状は、長さ３００ｍｍ、幅２５０ｍｍ、且つ表１，２に示す厚みを有するものである。なお、物品収納部材としてはラゲッジボックスが想定された。
(Preparation of molded body forming lower surface side of article storage member)
A pair of male and female molds were prepared. As the mold, one having an internal space in the shape of an article storage member was prepared. The shape on the lower surface side has a length of 300 mm, a width of 250 mm, and the thicknesses shown in Tables 1 and 2. A luggage box was assumed as the article storage member.
発泡粒子を、ラゲッジボックスの形状をした成形体に成形可能に設計された金型に充填し、スチーム加熱による型内成形方法を実施して、発泡粒子成形体を得た。なお、型内成形方法における加熱方法（スチーム加熱を行う方法）は次のように実施された。両面の型のドレン弁を開放した状態でスチームを５秒間金型内に供給して予備加熱（排気工程）を行った後、表１、表２に示す成形圧（成形蒸気圧）より０．０８ＭＰａ（Ｇ）低い圧力で一方加熱を行い、さらに表１、表２に示す成形蒸気圧より０．０４ＭＰａ（Ｇ）低い圧力で逆方向から一方加熱を行った後、表１、表２に示す成形蒸気圧で、両面から本加熱を行った。加熱終了後、放圧し、３０秒間空冷した後、金型を開放し型内成形された発泡粒子成形体を取り出した。得られた発泡粒子成形体は、８０℃のオーブンにて１２時間養生された。こうして、実施例１から８について、物品収納部材の下面を形成する連通空隙保有成形体となる発泡粒子成形体が得られた。比較例１から３については、物品収納部材の下面を形成する連通空隙保有成形体と比較されるための成形体をなす発泡粒子成形体が得られた。 The foamed particles were filled in a mold designed to be molded into a shaped body having a luggage box shape, and an in-mold molding method by steam heating was performed to obtain a foamed particle molded body. The heating method (method of performing steam heating) in the in-mold molding method was performed as follows. Steam was supplied into the mold for 5 seconds with the drain valves of the double-sided molds open, and preheating (evacuation process) was performed. Then, the molding pressure (molding steam pressure) shown in Tables 1 and 2 was set to 0. One heating is performed at a lower pressure of 08 MPa (G), and one heating is performed from the opposite direction at a pressure 0.04 MPa (G) lower than the molding vapor pressure shown in Tables 1 and 2, and then the results are shown in Tables 1 and 2. The main heating was performed from both sides with the forming vapor pressure. After the heating was completed, the pressure was released, and after air cooling for 30 seconds, the mold was opened and the foamed particle molded body molded in the mold was taken out. The obtained expanded particle molded body was cured in an oven at 80 ° C. for 12 hours. Thus, with respect to Examples 1 to 8, foamed particle molded bodies serving as communication void-containing molded bodies forming the lower surface of the article storage member were obtained. For Comparative Examples 1 to 3, foamed particle molded bodies were obtained that were molded to be compared with the communicating void-containing molded body forming the lower surface of the article storage member.
得られた発泡粒子成形体について、気泡膜厚、貫通孔平均径、成形体密度、成形体全体の空隙率（％）、成形体表層の空隙率（ａ）（表１，２中、表層空隙率）（％）、成形体内部の空隙率（ｂ）（表１，２中、内部空隙率）（％）、空隙率差（ａ−ｂの値）（％）、成形体の最小厚みが測定された。これらについて測定方法は、既述した方法が用いられた。結果は表１、表２に示すとおりである。 About the obtained foamed particle molded body, the bubble film thickness, the through-hole average diameter, the molded body density, the porosity of the entire molded body (%), the porosity of the molded body surface layer (a) (in Tables 1 and 2, the surface layer voids) Rate) (%), porosity inside the molded body (b) (in Tables 1 and 2, internal porosity) (%), porosity difference (value of ab) (%), minimum thickness of the molded body Measured. The measurement method described above was used for these. The results are as shown in Tables 1 and 2.
なお、表層部分の空隙率ａは、連通した空隙を有する発泡粒子成形体の断面写真を撮影し、その下面側の表面から３ｍｍまでの表層部分の断面写真から、空隙部分の面積と気泡膜（樹脂）部分の面積を算出し、その面積比率（面積％）として求めた。また、内部空隙率ｂは、成形体の内部に相当する部分を切り出して、その内部に相当する部分の断面写真を撮影し、その断面写真から、空隙部分の面積と気泡膜（樹脂）部分の面積を算出し、その面積比率（面積％）として求めた。 The porosity a of the surface layer portion is obtained by taking a cross-sectional photograph of a foamed particle molded body having continuous voids, and from the cross-sectional photograph of the surface layer portion up to 3 mm from the surface on the lower surface side, the area of the void portion and the bubble film ( The area of the (resin) portion was calculated, and the area ratio (area%) was obtained. Further, the internal porosity b is obtained by cutting out a portion corresponding to the inside of the molded body, taking a cross-sectional photograph of the portion corresponding to the inside, and from the cross-sectional photograph, the area of the void portion and the bubble film (resin) portion. The area was calculated and obtained as the area ratio (area%).
（吸音性）
得られた発泡粒子成形体を用いＪＩＳ Ａ１４０５−２に準拠した音響管による吸音率の測定により、吸音率が特定された。吸音率の測定は、連通した空隙を有する熱可塑性樹脂発泡粒子成形体で形成された吸音層部分において垂直入射吸音率測定器を用い、音響管直径１６ｍｍの音響管を使用し、２〜１０ｋＨｚの吸音率を測定することで測定された。また、周波数５．５ｋＨｚ、７．８ｋＨｚ、１０ｋＨｚにおける吸音率が、ｎ数＝３の平均値として算出された。垂直入射吸音率測定器としては、ＡＣＩＭＳ（株式会社神戸製鋼所製）が使用された。結果を表１，表２に示す。
(Sound absorption)
The sound absorption coefficient was specified by measuring the sound absorption coefficient with an acoustic tube in accordance with JIS A1405-2 using the obtained foamed particle molded body. The sound absorption coefficient is measured by using a normal incident sound absorption coefficient measuring device in a sound absorption layer portion formed of a thermoplastic resin foam particle molded body having a continuous void, using an acoustic tube having a diameter of 16 mm, and having a frequency of 2 to 10 kHz. It was measured by measuring the sound absorption rate. Further, the sound absorption coefficient at frequencies of 5.5 kHz, 7.8 kHz, and 10 kHz was calculated as an average value of n number = 3. ACIMS (manufactured by Kobe Steel, Ltd.) was used as a normal incident sound absorption coefficient measuring device. The results are shown in Tables 1 and 2.
参考例
（発泡粒子の調製）
内径９５ｍｍの芯層形成用押出機の出口側にストランド形成用ダイが取付けられた押出機を用い、芯層を構成するポリオレフィン系樹脂を押出機に供給し、溶融混練してそれぞれ溶融混練物とした。被覆層を形成させない以外は、実施例１と同様にして樹脂粒子、発泡粒子、及び、発泡粒子成形体を得た。得られた発泡粒子、及び、発泡粒子成形体を用いて実施例１と同様の測定を行った。結果は表１に示す。
Reference example (preparation of expanded particles)
Using an extruder having a strand forming die attached to the outlet side of the core layer forming extruder having an inner diameter of 95 mm, the polyolefin resin constituting the core layer is supplied to the extruder, and melted and kneaded, respectively. did. Resin particles, expanded particles, and expanded particle molded bodies were obtained in the same manner as in Example 1 except that the coating layer was not formed. The same measurement as in Example 1 was performed using the obtained expanded particles and the expanded particle molded body. The results are shown in Table 1.
１．物品収納部材
２．下面
３．上面
４．側壁
５．仕切り壁
６．連通空隙保有成形体
７．連通空隙保有成形体を形成する熱可塑性樹脂発泡粒子
８．貫通孔
９．発泡芯層
１０．被覆層
１２．蓋材
１５．自動車
１６．電気モーター
１７．インバータ
１８．車室
１９．トランクルーム
２０．座席シート
２１．収納部
２２．底面部
２３．吸音層
1. 1. Article storage member Lower surface 3. Upper surface 4. 4. Side wall Partition wall6. 6. Molded body with communicating voids 7. Foamed thermoplastic resin particles that form a molded article having a continuous void. Through hole 9. Foam core layer 10. Cover layer 12. Lid 15. Automobile 16. Electric motor 17. Inverter 18. Car compartment 19. Trunk room 20. Seat seat 21. Storage unit 22. Bottom portion 23. Sound absorbing layer
Claims (8)
該物品収納部材は、少なくとも下面側に、連通した空隙を有する熱可塑性樹脂発泡粒子成形体で形成された吸音層を有しており、
該連通した空隙を有する熱可塑性樹脂発泡粒子成形体全体の空隙率が１５％以上５０％以下であり、該連通した空隙を有する熱可塑性樹脂発泡粒子成形体の表層部分の空隙率が１５％以上であり、
該表層部分の空隙率が、該表層部分を除いた成形体の内部の空隙率よりも大きい、または、該表層部分の空隙率と該成形体の内部の空隙率とが等しい、ことを特徴とする自動車用物品収納部材。
In an automotive article storage member comprising a thermoplastic resin foam particle molded body and having a concave storage portion opened upward,
The article storage member has, on at least the lower surface side, a sound absorbing layer formed of a thermoplastic resin foamed particle molded body having a continuous void.
The porosity of the entire thermoplastic resin foam particle molded body having the continuous voids is 15% or more and 50% or less, and the porosity of the surface layer portion of the thermoplastic resin foam particle molded body having the continuous voids is 15% or more. der is,
The porosity of the surface layer portion is larger than the porosity of the molded body excluding the surface layer portion, or the porosity of the surface layer portion and the porosity of the molded body are equal. Article storage member for automobile.
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| JP2023057790A (en) | 2021-10-12 | 2023-04-24 | 株式会社ジェイエスピー | Expanded polypropylene-based-resin particles and method for producing molded expanded-particle object |
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| JP2787224B2 (en) * | 1989-05-15 | 1998-08-13 | 株式会社ジェイ エス ピー | Olefin-based resin foam molded article and method for producing the same |
| JPH05147120A (en) * | 1991-11-28 | 1993-06-15 | Mitsubishi Yuka Badische Co Ltd | Manufacture of porous structure |
| JP2805286B2 (en) * | 1994-08-16 | 1998-09-30 | 株式会社ジェイエスピー | Polyolefin-based resin foam molded article having communicating voids and method for producing the same |
| JP3759997B2 (en) * | 1996-07-12 | 2006-03-29 | 株式会社ジェイエスピー | Luggage box |
| JP4582674B2 (en) * | 2000-10-11 | 2010-11-17 | 株式会社ジェイエスピー | Polyester resin expanded particles and molded articles thereof |
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