JP5477197B2 - Speaker diaphragm - Google Patents
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- JP5477197B2 JP5477197B2 JP2010146470A JP2010146470A JP5477197B2 JP 5477197 B2 JP5477197 B2 JP 5477197B2 JP 2010146470 A JP2010146470 A JP 2010146470A JP 2010146470 A JP2010146470 A JP 2010146470A JP 5477197 B2 JP5477197 B2 JP 5477197B2
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Description
本発明は、特定のサイズの発泡粒子からなる熱可塑性樹脂粒子発泡成形体から得られる熱可塑性樹脂粒子発泡フィルムを用いたスピーカー用振動板に関する。更に詳しくは、携帯電話などに使用するダイナミック型小型スピーカーやダイナミック型平面スピーカーの振動膜の部材として好適に使用しうる 熱可塑性樹脂粒子発泡成形体を切削する工程を含んでなる熱可塑性樹脂粒子発泡フィルム及びそれを用いた積層複合材に関する。 The present invention relates to a loudspeaker diaphragm using a foamed thermoplastic resin particle film obtained from a foamed thermoplastic resin particle formed of foam particles of a specific size. More specifically, foaming of thermoplastic resin particles comprising a step of cutting a foamed product of thermoplastic resin particles that can be suitably used as a vibration membrane member for dynamic type small speakers and dynamic type flat speakers used in mobile phones and the like. The present invention relates to a film and a laminated composite material using the film.
近年、携帯電話やスマートフォンなどの移動通信端末の小型化、高機能化、さらには、平面型テレビの薄肉化に伴い、搭載されるスピーカーに対しても、小型化、薄肉化、省電力化、音質改良に対する要求が高まっている。 In recent years, as mobile communication terminals such as mobile phones and smartphones have become smaller and more functional, and flat panel televisions have become thinner, the size of the installed speakers has also been reduced. There is an increasing demand for sound quality improvement.
スピーカーを小型化する技術として、従来同様、磁石とコイルを用いて振動膜を振動させるダイナミック型以外に、セラミックなどの圧電材料を用いた圧電型スピーカーが挙げられ、小型化、特に薄肉化に関しては、圧電型の方が有利とされているが、音質の観点、特に低音域の音の再現性に関してはダイナミック型の方が優れており、音質を重視する場合にはダイナミック型が採用される傾向にある。 In addition to the dynamic type that vibrates the vibration film using magnets and coils as in the past, piezoelectric speakers using a piezoelectric material such as ceramic can be cited as a technology for downsizing the speaker. However, the piezoelectric type is more advantageous, but the dynamic type is superior in terms of sound quality, especially the low-frequency sound reproducibility, and the dynamic type tends to be adopted when emphasizing sound quality. It is in.
また、圧電型に比べ音質に優れるダイナミック型においても、小型のものは振動膜が平面である場合が多く、振動膜がコーン形状の場合に比べ中音域の音質が劣る傾向にあり、まだまだ改良の余地が残されていた。 Also, in the dynamic type, which is superior in sound quality compared to the piezoelectric type, the smaller ones often have a flat diaphragm, and the mid-range tone quality tends to be inferior compared to the cone-shaped diaphragm. There was room left.
ダイナミック型平面スピーカーの音質を改良する試みとしては、特許文献１では、振動膜における、低次の振動モードに基づく振動の振幅を抑えて中音領域の音質を改良する目的で、振動膜にＰＥＴ（ポリエチレンテレフタレート）やＰＥＮ（ポリエチレンナフタレート）などの発泡体を貼付する試みが提案されている。また特許文献２では、独立気泡の低発泡ポリエチレンの両面にアルミニウムの面材を積相した複合板を振動板とすることが提案されている。しかしながら、ポリエチレンは耐熱性が低く、８０℃程度の温度下では剛性が大きく低下し、音質が変化することから携帯電話などへの適用は好ましくない。また、ポリエチレンテレフタレートもガラス転移温度が高くないため耐熱性は充分ではない。一方、ポリエチレンナフタレートは耐熱性が高く、８０℃程度では剛性低下が小さいため好ましいが、樹脂が高価であるため、汎用性に欠ける。更には、ポリエチレンテレフタレートやポリエチレンナフタレートは、高圧容器中で炭酸ガスなどの不活性ガスを浸透させ、圧力開放した後加熱発泡するなどの煩雑なバッチプロセスを適用せざるを得ず、製造コストが高いなどの欠点があった。 As an attempt to improve the sound quality of a dynamic flat speaker, in Patent Document 1, in order to improve the sound quality of the middle sound region by suppressing the amplitude of vibration based on the low-order vibration mode in the vibration film, PET is used as the vibration film. Attempts have been made to affix foams such as (polyethylene terephthalate) and PEN (polyethylene naphthalate). Patent Document 2 proposes that a diaphragm is a composite plate in which aluminum face materials are stacked on both sides of closed-cell low-foam polyethylene. However, polyethylene has low heat resistance, and its rigidity is greatly reduced at a temperature of about 80 ° C., and the sound quality changes. Also, polyethylene terephthalate is not high in heat resistance because its glass transition temperature is not high. On the other hand, polyethylene naphthalate is preferable because it has high heat resistance and a stiffness reduction of about 80 ° C. is small, but lacks versatility because the resin is expensive. Furthermore, polyethylene terephthalate and polyethylene naphthalate must be subjected to a complicated batch process such as infiltration of an inert gas such as carbon dioxide gas in a high-pressure vessel, heat release after releasing the pressure, and the production cost is increased. There were drawbacks such as high.
更には、市場において、ポリフェニレンエーテル系樹脂とポリスチレン系樹脂からなる変性ポリフェニレンエーテル系樹脂の予備発泡粒子を型内成型し、薄くスライスした発泡フィルムの両面にアルミニウム箔を積層した複合積層材を振動板に貼付したスピーカーが使用されている。しかしながら、予備発泡粒子の直径が２０００μｍ以上と大きく、セル径のばらつきも大きいことから、特に振動板自体が小さい小型スピーカーの場合、高密度である粒子の融着面が不規則に存在するため、得られる複合積層材が均一性に欠けるなどの欠点があった。 Furthermore, on the market, a composite laminated material in which pre-expanded particles of modified polyphenylene ether resin consisting of polyphenylene ether resin and polystyrene resin are molded in-mold, and aluminum foil is laminated on both sides of a thin sliced foam film is used as a diaphragm. The speaker affixed to is used. However, since the diameter of the pre-expanded particles is as large as 2000 μm or more and the variation in the cell diameter is large, especially in the case of a small speaker with a small diaphragm itself, the fused surface of the particles having high density exists irregularly, There were drawbacks such as the resulting composite laminate lacking uniformity.
一方、特許文献３では、ポリフェニレンエーテル系樹脂とポリスチレン系樹脂からなる、特定方向への加熱収縮率が大きな積層発泡シートが提案されており、ここで厚み０．２５〜０．５ｍｍの発泡フィルムが開示されている。しかしながら、この発泡フィルムは加熱収縮率を大きくする目的で押出方向に強く延伸して得るため、セルが厚み方向に大きく扁平しており、剛性に欠けるものであった。 On the other hand, Patent Document 3 proposes a laminated foamed sheet composed of a polyphenylene ether resin and a polystyrene resin and having a large heat shrinkage rate in a specific direction. Here, a foamed film having a thickness of 0.25 to 0.5 mm is proposed. It is disclosed. However, since this foamed film is obtained by strongly stretching in the extrusion direction for the purpose of increasing the heat shrinkage rate, the cell is greatly flattened in the thickness direction and lacks rigidity.
更に、特許文献４では、ポリフェニレンエーテル系樹脂とポリスチレン系樹脂からなる変性ポリフェニレンエーテル系樹脂からなる、密度６０〜３００ｋｇ／ｍ３、厚み０．１〜０．５ｍｍ、厚み方向の平均セル径Ａと押出方向の平均セル径Ｂ、幅方向平均セル径Ｃの比Ａ／ＢおよびＡ／Ｃがいずれも０．２〜１であることを特徴とする変性ポリフェニレンエーテル系樹脂押出発泡フィルムが開示されているが、押出発泡で製造することから、気泡を充分に真球としえずに若干ながら扁平するため、剛性向上にまだ改良の余地があった。 Furthermore, in Patent Document 4, a density of 60 to 300 kg / m 3 , a thickness of 0.1 to 0.5 mm, and an average cell diameter A in the thickness direction, which are made of a modified polyphenylene ether resin composed of a polyphenylene ether resin and a polystyrene resin, Disclosed is a modified polyphenylene ether resin extruded foam film characterized in that the ratio A / B and A / C of the average cell diameter B in the extrusion direction and the average cell diameter C in the width direction are both 0.2 to 1. However, since it is manufactured by extrusion foaming, the bubbles are flattened slightly without being fully spherical, so there is still room for improvement in rigidity.
本発明の目的は、携帯電話やスマートフォンなどの移動通信端末の小型化、高機能化、さらには平面型テレビの薄肉化に伴い、搭載されるスピーカーに対して高まっている、小型化、薄肉化、省電力化、音質改良の要求に答えられる、軽量で剛性が高く、かつ、高温下であっても剛性の変化が少ない、携帯電話などに使用するダイナミック型小型スピーカーやダイナミック型平面スピーカーの振動膜の部材に好適に使用しうるスピーカー用振動板を提供することにある。 The object of the present invention is to reduce the size and thickness of a mobile communication terminal such as a mobile phone or a smart phone, which has been increased with respect to a speaker to be mounted along with the downsizing and high functionality of the mobile communication terminal and the thinning of a flat-screen television. Vibration of small dynamic type speakers and dynamic type flat speakers used for mobile phones, etc. that can respond to demands for power saving, sound quality improvement, light weight and high rigidity, and little change in rigidity even under high temperature An object of the present invention is to provide a speaker diaphragm that can be suitably used for a membrane member.
本発明者らは前記課題を解決すべく鋭意研究を重ねた結果、特定のサイズの予備発泡粒子からなる熱可塑性樹脂粒子発泡成形体から得られる熱可塑性樹脂粒子発泡フィルムが、表面均一性が高く、軽量かつ剛性に優れ、さらに８５℃の高温下においても剛性の変化が小さいことを見出し、該フィルム単独でも、さらには、該フィルムの両側にアルミニウム箔を積層してなる積層複合材でも、携帯電話、スマートフォン、平面型テレビなどに搭載されるダイナミック型小型スピーカーやダイナミック型平面スピーカーに対する小型化、薄肉化、省電力化、音質改良に対する要求に答えることができ、スピーカー用振動板として好適に使用可能であることを見出し、本発明の完成に至った。 As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a thermoplastic resin particle foamed film obtained from a thermoplastic resin particle foam molded article made of pre-expanded particles of a specific size has high surface uniformity. It was found to be lightweight and rigid, and the change in rigidity was small even at a high temperature of 85 ° C., and the film alone or even a laminated composite made by laminating aluminum foil on both sides of the film can be carried. It can meet the demands for miniaturization, thinning, power saving, and sound quality improvement for dynamic small speakers and dynamic flat speakers mounted on phones, smartphones, flat TVs, etc. It was found that this was possible, and the present invention was completed.
すなわち本発明は以下の通りである。
１）予備発泡粒子を用いて製造された熱可塑性樹脂粒子発泡成形体から得られた、厚みが０．１ｍｍ以上１．５ｍｍ以下の熱可塑性樹脂粒子発泡フィルムを用いたスピーカー用振動板であって、上記予備発泡粒子が実質的に直径１５００μｍ以下のもののみからなり、上記熱可塑性樹脂粒子発泡成形体が、アクリロニトリルを５重量％以上５０重量％以下含有し、密度が１００ｋｇ／ｍ 3 以上５００ｋｇ／ｍ 3 以下、ガラス転移温度が１０５℃以上であるスチレン系樹脂粒子発泡成形体であって、発泡成形体内部に、実質的に粒子状の未発泡部位が存在しないことを特徴とするスピーカー用振動板。
２）上記予備発泡粒子が実質的に直径３００μｍ以上のもののみからなることを特徴とする上記１）記載のスピーカー用振動板。
３）上記１）または２）記載の熱可塑性樹脂粒子発泡フィルムの両側にアルミニウム箔を積層してなることを特徴とするスピーカー用振動板。
４）上記熱可塑性樹脂粒子発泡成形体を切削する工程を含んで得られたことを特徴とする、上記１）〜３）のいずれか記載のスピーカー用振動板。
５）熱可塑性樹脂粒子発泡成形体を切削する工程を含んで得られた熱可塑性樹脂粒子発泡フィルムが、熱可塑性樹脂粒子発泡成形体或いは刃の少なくとも一方を往復運動させ、かつ、往路或いは復路の少なくとも一方の工程において熱可塑性樹脂粒子発泡成形体と刃が摺動することにより熱可塑性樹脂粒子発泡成形体を間歇的に切削することにより得られた熱可塑性樹脂粒子発泡フィルムであることを特徴とする、上記４）記載のスピーカー用振動板。
６）熱可塑性樹脂粒子発泡成形体を切削する工程を含んで得られた熱可塑性樹脂粒子発泡フィルムが、熱可塑性樹脂粒子発泡成形体を切削して薄片とした後、該薄片を、該熱可塑性樹脂のガラス転移温度−３０℃以上の温度、かつガラス転移温度以下の温度にて加熱しつつ平板化することにより得られたものであることを特徴とする、上記４）記載のスピーカー用振動板。
７）熱可塑性樹脂粒子発泡フィルムの、密度１００ｋｇ／ｍ3以上５００ｋｇ／ｍ3以下、１０％圧縮時の圧縮強度が０．８ＭＰａ以上であることを特徴とする、上記１）〜６）のいずれか記載のスピーカー用振動板。
That is, the present invention is as follows.
1) A speaker diaphragm using a thermoplastic resin particle foam film having a thickness of 0.1 mm or more and 1.5 mm or less, obtained from a thermoplastic resin particle foam molded article produced using pre-expanded particles. the pre-expanded particles Ri Do because only the following substantially diametrically 1500 .mu.m, the thermoplastic resin particle foamed molded article, acrylonitrile containing 5% by weight to 50% by weight, a density of 100 kg / m 3 or more 500kg / M 3 or less, and a glass transition temperature of 105 ° C. or more, which is a foamed molded product of a styrene resin particle, wherein there is substantially no particulate unfoamed portion inside the foamed molded product Diaphragm.
2) The loudspeaker diaphragm according to 1), wherein the pre-expanded particles are substantially composed only of particles having a diameter of 300 μm or more.
3) A loudspeaker diaphragm, wherein an aluminum foil is laminated on both sides of the thermoplastic resin particle foam film described in 1) or 2) above.
4) The loudspeaker diaphragm according to any one of 1) to 3) above, which is obtained by cutting the thermoplastic resin particle foam molded article.
5 ) The thermoplastic resin particle foam film obtained by cutting the thermoplastic resin particle foam molded article reciprocates at least one of the thermoplastic resin particle foam molded article or the blade, and travels forward or backward. It is a thermoplastic resin particle foam film obtained by intermittently cutting a thermoplastic resin particle foam molding by sliding a thermoplastic resin particle foam molding and a blade in at least one step. The speaker diaphragm according to 4) above.
6 ) After the thermoplastic resin particle foam film obtained including the step of cutting the thermoplastic resin particle foam molded article cuts the thermoplastic resin particle foam molded article into thin pieces, the thin pieces are converted into the thermoplastic resin. 4. The speaker diaphragm as described in 4) above, which is obtained by flattening while heating at a glass transition temperature of a resin of −30 ° C. or more and a temperature of the glass transition temperature or less. .
7 ) The thermoplastic resin particle foamed film has a density of 100 kg / m 3 or more and 500 kg / m 3 or less, and a compressive strength at 10% compression of 0.8 MPa or more, any of the above 1) to 6 ) Or a diaphragm for a speaker.
本発明は、実質的に直径１４００μｍ以下の予備発泡粒子のみ、あるいは、直径１４００μｍ以下、３００μｍ以上の予備発泡粒子のみで構成され、厚みが０．１ｍｍ以上、１．５ｍｍ以下の熱可塑性樹脂粒子発泡フィルムを単独に用いた、または、該フィルムの両側にアルミニウム箔を積層してなる積層複合材を用いたスピーカー用振動板に関する。なお、本発明における粒子の直径とはＪＩＳ Ｚ８８０１に基づく呼び寸法の網ふるいの通過を意味しており、例えば、直径１５００μｍ以下、とは、呼び寸法１５００μｍを通過したことを意味する。 The present invention substantially comprises only pre-expanded particles having a diameter of 1400 μm or less, or only pre-expanded particles having a diameter of 1400 μm or less and 300 μm or more, and has a thickness of 0.1 mm or more and 1.5 mm or less. The present invention relates to a speaker diaphragm using a film alone or using a laminated composite material in which aluminum foil is laminated on both sides of the film. In addition, the diameter of the particle | grains in this invention means passage of the net sieve of the nominal dimension based on JISZ8801, for example, the diameter of 1500 micrometers or less means having passed the nominal dimension 1500 micrometers.
本発明のスピーカー振動板としての性能である広い音域や、高い音圧をより効率良く発揮する上で、本発明における予備発泡粒子の直径は１４００μｍ以下であり、１０００μｍ以下が更に好ましい。一方、後述する予備発泡工程において加熱ムラなどにより十分に膨張しなかった粒子を除くという観点から、本発明における予備発泡粒子の直径は３００μｍ以上であり、５００μｍ以上が更に好ましい。なお、予備発泡工程において十分に発泡しなかった粒子が混入すると、熱可塑性樹脂粒子発泡フィルムに突起状の厚みムラが形成されたり、切削により熱可塑性樹脂粒子発泡フィルムを製造する際に刃が欠ける要因となるため、取り除く必要がある。 The diameter of the pre-expanded particles in the present invention is 1400 μm or less, more preferably 1000 μm or less, in order to more efficiently exhibit a wide sound range and high sound pressure as the performance of the speaker diaphragm of the present invention. On the other hand, from the viewpoint of removing particles that are not sufficiently expanded due to heating unevenness or the like in the pre-foaming step described later, the diameter of the pre-foamed particles in the present invention is 300 μm or more, and more preferably 500 μm or more. If particles that are not sufficiently foamed in the pre-foaming step are mixed, protrusion-like thickness unevenness is formed in the thermoplastic resin particle foam film, or the blade is chipped when manufacturing the thermoplastic resin particle foam film by cutting. It becomes a factor and needs to be removed.
本発明における熱可塑性樹脂粒子発泡フィルムの厚みは、０．１ｍｍ以上１．５ｍｍ以下であり、好ましくは、０．１５ｍｍ以上０．７ｍｍ以下であり、特に好ましくは０．２ｍｍ以上０．４ｍｍ以下である。厚みが０．１ｍｍを下回ると、特に厚みムラで肉薄になった部位で剛性低下が大きく、１．５ｍｍを超えると狭い部位での使用が制限され、薄肉化の要求に答えられなくなる。 The thickness of the foamed thermoplastic resin particle film in the present invention is from 0.1 mm to 1.5 mm, preferably from 0.15 mm to 0.7 mm, particularly preferably from 0.2 mm to 0.4 mm. is there. When the thickness is less than 0.1 mm, the rigidity is greatly reduced particularly in a portion that is thin due to uneven thickness, and when the thickness exceeds 1.5 mm, use in a narrow portion is restricted, and the request for thinning cannot be answered.
また本発明における熱可塑性樹脂粒子発泡フィルムの１０％圧縮時の圧縮強度は、０．８ＭＰａ以上であり、好ましくは１．０ＭＰａである。１０％圧縮時の圧縮強度が０．８ＭＰａを下回ると、積層発泡フィルムとした際に十分な剛性が得られない。
また本発明における熱可塑性樹脂粒子発泡フィルムの密度については、１００ｋｇ／ｍ３以上５００ｋｇ／ｍ３以下であり、好ましくは、１２０ｋｇ／ｍ３以上３００ｋｇ／ｍ３以下である。密度が１００ｋｇ／ｍ３を下回ると、スライスにより得られる発泡フィルムの剛性が不足し、５００ｋｇ／ｍ３を超えると上記発泡フィルムの軽量性が損なわれる。
Moreover, the compressive strength at the time of 10% compression of the thermoplastic resin particle foam film in the present invention is 0.8 MPa or more, preferably 1.0 MPa. When the compression strength at 10% compression is less than 0.8 MPa, sufficient rigidity cannot be obtained when a laminated foam film is obtained.
The density of the thermoplastic resin particle foam film in the present invention is 100 kg / m 3 or more and 500 kg / m 3 or less, preferably 120 kg / m 3 or more and 300 kg / m 3 or less. When the density is less than 100 kg / m 3 , the rigidity of the foamed film obtained by slicing is insufficient, and when it exceeds 500 kg / m 3 , the lightweight property of the foamed film is impaired.
この様な熱可塑性樹脂粒子発泡フィルムを得るには、基材である熱可塑性樹脂の剛性が高いことが好ましく、例えば、スチレン単独重合体、スチレン／アクリロニトリル共重合体、スチレン／α−メチルスチレン共重合体、スチレン／メタクリル酸共重合体、スチレン／α−メチルスチレン／アクリロニトリル共重合体、α−メチルスチレン／アクリロニトリル共重合体などのスチレン系樹脂、スチレン単独重合体とポリフェニレンエーテル系樹脂の混合物、スチレン／ブタジエン共重合体とポリフェニレンエーテル系樹脂の混合物などの変性ポリフェニレンエーテル系樹脂、メタクリル酸メチル単独重合体、メタクリル酸メチル／アクリル酸メチル共重合体などのポリメタクリル酸メチル系樹脂、エチレン／ノルボルネン類共重合体、エチレン／ジシクロペンタジエン共重合体などの環状オレフィン系樹脂、プロピレン単独重合体、プロピレン／エチレン共重合体、プロピレン／ブテン共重合体、エチレン単独重合体、エチレン／ブテン共重合体などのポリオレフィン系樹脂などが挙げられる。 In order to obtain such a foamed thermoplastic resin particle film, it is preferable that the thermoplastic resin as the base material has high rigidity. For example, styrene homopolymer, styrene / acrylonitrile copolymer, styrene / α-methylstyrene copolymer Polymer, styrene / methacrylic acid copolymer, styrene / α-methylstyrene / acrylonitrile copolymer, styrene resin such as α-methylstyrene / acrylonitrile copolymer, mixture of styrene homopolymer and polyphenylene ether resin, Modified polyphenylene ether resin such as a mixture of styrene / butadiene copolymer and polyphenylene ether resin, methyl methacrylate homopolymer, polymethyl methacrylate resin such as methyl methacrylate / methyl acrylate copolymer, ethylene / norbornene Copolymer, Ethylene / Olefinic resins such as dicyclopentadiene copolymers, propylene homopolymers, propylene / ethylene copolymers, propylene / butene copolymers, ethylene homopolymers, polyolefin resins such as ethylene / butene copolymers, etc. Is mentioned.
更には、基材である熱可塑性樹脂のガラス転移温度（以下、Ｔｇと表記する場合がある）は１０５℃以上であることが、携帯電話などに求められる８５℃環境下においても、寸法変化や剛性低下が小さく、また耐熱性の高いホットメルト接着剤を用いてアルミニウム箔などを積層する際にも寸法変化が小さいことから好ましい。 Further, the glass transition temperature of the thermoplastic resin as the base material (hereinafter sometimes referred to as Tg) is 105 ° C. or higher, and even under the 85 ° C. environment required for mobile phones, It is preferable because the dimensional change is small when laminating an aluminum foil or the like using a hot-melt adhesive having a low rigidity and high heat resistance.
なお、本発明において熱可塑性樹脂のガラス転移温度は、示差走査熱量測定（ＤＳＣ）において、試料１〜１０ｍｇを４０℃から２１０℃まで１０℃／分の速度で昇温、該温度で５分間保持後、ついで２１０℃から４０℃まで１０℃／分の速度で降温、当該温度で５分間保持後、再度４０℃から２１０℃まで１０℃／分の速度で昇温したときのチャートにおいて観察される２箇所の屈曲点の中間温度を言う。 In the present invention, the glass transition temperature of the thermoplastic resin is as follows. In differential scanning calorimetry (DSC), 1 to 10 mg of the sample is heated from 40 ° C. to 210 ° C. at a rate of 10 ° C./min and held at that temperature for 5 minutes. Then, the temperature is lowered from 210 ° C. to 40 ° C. at a rate of 10 ° C./min, held at that temperature for 5 minutes, and then observed again in the chart when the temperature is raised from 40 ° C. to 210 ° C. at a rate of 10 ° C./min. An intermediate temperature between two bending points.
この様な熱可塑性樹脂としては、例えば上記の内、スチレン／アクリロニトリル共重合体、スチレン／α−メチルスチレン共重合体、スチレン／メタクリル酸共重合体、スチレン／α−メチルスチレン／アクリロニトリル共重合体、α−メチルスチレン／アクリロニトリル共重合体、スチレン単独重合体とポリフェニレンエーテル系樹脂の混合物、スチレン／ブタジエン共重合体とポリフェニレンエーテル系樹脂の混合物、エチレン／ノルボルネン類共重合体、エチレン／ジシクロペンタジエン共重合体、などが挙げられる。 Examples of such a thermoplastic resin include, among the above, styrene / acrylonitrile copolymer, styrene / α-methylstyrene copolymer, styrene / methacrylic acid copolymer, styrene / α-methylstyrene / acrylonitrile copolymer. , Α-methylstyrene / acrylonitrile copolymer, mixture of styrene homopolymer and polyphenylene ether resin, mixture of styrene / butadiene copolymer and polyphenylene ether resin, ethylene / norbornene copolymer, ethylene / dicyclopentadiene A copolymer, and the like.
これらの内、比較的Ｔｇの高い熱可塑性樹脂で、かつ、既存の生産性の高い方法で発泡性粒子を得ることが可能であることから、スチレン／アクリロニトリル共重合体、スチレン／α−メチルスチレン共重合体、スチレン／メタクリル酸共重合体、スチレン／α−メチルスチレン／アクリロニトリル共重合体、α−メチルスチレン／アクリロニトリル共重合体などのスチレン系樹脂が最も好ましく、さらには、アクリロニトリルを５重量％以上５０重量％以下含有するスチレン系樹脂が好ましい。上記スチレン系モノマーとしては、スチレン、α−メチルスチレン、ジビニルベンゼン、ｐ−メチルスチレン、ｔ−ブチルスチレンなどの１種または２種以上が挙げられる。さらに、これらの内、安価でかつ樹脂とした際の耐熱性がさらに高いことから、α−メチルスチレン、またはスチレンとα−メチルスチレンの併用が好ましい。アクリロニトリルの含有量が５％未満では、重合後のスチレン系モノマーの残存が多くなり、５０重量％を越えると発泡剤の含浸量が低下すると共に、発泡成形体中に硬芯が増加する。 Among these, since it is possible to obtain expandable particles by a thermoplastic resin having a relatively high Tg and by an existing high productivity method, styrene / acrylonitrile copolymer, styrene / α-methylstyrene. Most preferred are styrene resins such as copolymers, styrene / methacrylic acid copolymers, styrene / α-methylstyrene / acrylonitrile copolymers, α-methylstyrene / acrylonitrile copolymers, and 5% by weight of acrylonitrile. Styrenic resins containing at least 50% by weight are preferred. Examples of the styrenic monomer include one or more of styrene, α-methylstyrene, divinylbenzene, p-methylstyrene, t-butylstyrene, and the like. Further, among these, α-methylstyrene or a combination of styrene and α-methylstyrene is preferable because it is inexpensive and has higher heat resistance when used as a resin. If the acrylonitrile content is less than 5%, the amount of styrene monomer after polymerization increases, and if it exceeds 50% by weight, the amount of impregnation of the foaming agent decreases and the hard core increases in the foamed molded article.
一方で、スチレン系モノマーとアクリロニトリルを共重合する工程において、本発明の効果を損なわない範囲で、他のモノマーを配合してもよい。前記他のモノマーとしては、ブタジエン、イソプレン、無水マレイン酸、メタクリル酸、メタクリル酸メチル、などが例示される。 On the other hand, you may mix | blend another monomer in the process which copolymerizes a styrene-type monomer and acrylonitrile in the range which does not impair the effect of this invention. Examples of the other monomer include butadiene, isoprene, maleic anhydride, methacrylic acid, and methyl methacrylate.
本発明におけるスチレン系樹脂の重合に使用する重合開始剤としては、有機過酸化物を用いるが、１０時間半減期温度が６０℃以上１２０℃以下であることが、重合転化率を高くしやすいことから好ましい。この様な重合開始剤としては、例えば、１，１−ジ（ｔ−ブチルパーオキシ）シクロヘキサン、１，１−ジ（ｔ−ブチルパーオキシ）−３，３，５−トリメチルシクロヘキサン、１，１−ジ（ｔ−ブチルパーオキシ）−２−メチルシクロヘキサン、１，１−ジ（ｔ−ヘキシルパーオキシ）−３，３，５−トリメチルシクロヘキサン、ジ（ｔ−ブチルパーオキシ）ヘキサハイドロテレフタレート、２，５−ジメチル−２，５−ジ（２−エチルヘキサノニルパーオキシ）ヘキサン、ジ（ｔ−ブチルパーオキシイソプロピル）ベンゼン、ジベンゾイルパーオキサイド、ｔ−ブチルパーオキシイソプロピルモノカーボネート、ｔ−ブチルパーオキシベンゾエート、２，２−ジ（ｔ−ブチルパーオキシ）ヘキサン、等が挙げられる。これらは１種でも２種以上で用いてもよく、また他の重合開始剤を併用しても良い。 As the polymerization initiator used for the polymerization of the styrene resin in the present invention, an organic peroxide is used, but a 10 hour half-life temperature of 60 ° C. or more and 120 ° C. or less tends to increase the polymerization conversion rate. To preferred. Examples of such a polymerization initiator include 1,1-di (t-butylperoxy) cyclohexane, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1 -Di (t-butylperoxy) -2-methylcyclohexane, 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, di (t-butylperoxy) hexahydroterephthalate, 2 , 5-Dimethyl-2,5-di (2-ethylhexanonylperoxy) hexane, di (t-butylperoxyisopropyl) benzene, dibenzoyl peroxide, t-butylperoxyisopropyl monocarbonate, t-butylper Examples thereof include oxybenzoate and 2,2-di (t-butylperoxy) hexane. These may be used alone or in combination of two or more, and other polymerization initiators may be used in combination.
本発明において用いる基材である熱可塑性樹脂の一つの候補であるスチレン系樹脂の重合方法としては、塊状重合、懸濁重合、乳化重合など公知の方法が挙げられる。これらの内、重合後に再度粒子化することなくスチレン系樹脂粒子が得られ、発泡剤を含浸して発泡性スチレン系樹脂粒子とし得ることから、懸濁重合が好ましい。上記懸濁重合の方法としては、例えば、前記スチレン系モノマー及びアクリロニトリルを、燐酸カルシウム、ハイドロキシアパタイト、ピロリン酸マグネシウムなどの難水溶性無機塩や、α−オレフィンスルフォン酸ソーダ、ドデシルベンゼンスルフォン酸ソーダなどのアニオン性界面活性剤を併用して水中に分散させ、重合開始剤などを加えて加熱することによりスチレン系樹脂粒子を得ることができる。 Examples of the polymerization method of the styrene resin that is one candidate of the thermoplastic resin that is the base material used in the present invention include known methods such as bulk polymerization, suspension polymerization, and emulsion polymerization. Among these, suspension polymerization is preferable because styrene resin particles can be obtained without being re-particulated after polymerization and can be impregnated with a foaming agent to form expandable styrene resin particles. Examples of the suspension polymerization method include, for example, the above styrene monomer and acrylonitrile, sparingly water-soluble inorganic salts such as calcium phosphate, hydroxyapatite, and magnesium pyrophosphate, α-olefin sodium sulfonate, sodium dodecylbenzene sulfonate, and the like. A styrenic resin particle can be obtained by using an anionic surfactant in combination and dispersing in water, adding a polymerization initiator, and heating.
本発明において用いる発泡性スチレン系樹脂粒子は、スチレン系樹脂粒子に発泡剤を含浸させたものであり、発泡剤を含浸させる方法としては、スチレン系樹脂粒子を水中に分散させた状態で発泡剤を加える、スチレン系樹脂粒子を発泡剤中に浸漬する、押出機内にて溶融したスチレン系樹脂と発泡剤を溶融混練し細孔状のダイから押出しつつ急冷・カッティングを行う、などの方法が挙げられるが、スチレン系樹脂粒子を水中に分散させた状態で発泡剤を加える方法が好ましく、より好ましくは、スチレン系樹脂粒子を懸濁重合により重合する際に、重合の途中、あるいは重合後に発泡剤を含浸させて発泡性スチレン系樹脂粒子を得る方法が、生産性の観点から好ましい。 The expandable styrene resin particles used in the present invention are obtained by impregnating styrene resin particles with a foaming agent. As a method of impregnating the foaming agent, the foaming agent is obtained by dispersing styrene resin particles in water. , Immersing styrene-based resin particles in a foaming agent, melting and kneading a styrene-based resin melted in an extruder and a foaming agent, and performing rapid cooling and cutting while extruding from a pore-shaped die. However, a method of adding a foaming agent in a state where styrene resin particles are dispersed in water is preferable, and more preferably, when the styrene resin particles are polymerized by suspension polymerization, during or after the polymerization, From the viewpoint of productivity, a method of obtaining expandable styrene resin particles by impregnating with styrene is preferable.
本発明において使用することの出来る発泡剤としては、プロパン、イソブタン、ノルマルブタン、イソペンタン、ノルマルペンタン、ネオペンタンなど炭素数３以上５以下の炭化水素等の脂肪族炭化水素類、およびジフルオロエタン、テトラフルオロエタンなどのオゾン破壊係数がゼロであるフッ化炭化水素類などの揮発性発泡剤が挙げられる。また、これらの発泡剤を併用することもできる。 Examples of the blowing agent that can be used in the present invention include aliphatic hydrocarbons such as hydrocarbons having 3 to 5 carbon atoms such as propane, isobutane, normal butane, isopentane, normal pentane, and neopentane, and difluoroethane and tetrafluoroethane. And volatile foaming agents such as fluorinated hydrocarbons having zero ozone depletion coefficient. Moreover, these foaming agents can also be used together.
発泡剤の使用量としては、スチレン系樹脂粒子１００重量部に対して、好ましくは０．５重量部以上１２重量部以下、更に好ましくは２重量部以上９重量部以下である。 The amount of the foaming agent to be used is preferably 0.5 parts by weight or more and 12 parts by weight or less, more preferably 2 parts by weight or more and 9 parts by weight or less with respect to 100 parts by weight of the styrene resin particles.
本発明において用いる基材である熱可塑性樹脂の一つの候補である発泡性スチレン系樹脂粒子の製造方法は、例えば以下のとおりである。所定量の水性懸濁媒体中に所定量のスチレン系モノマー及びアクリロニトリル、重合開始剤、必要に応じてその他添加剤を添加し、所定の温度、好ましくは９０℃以上１００℃未満で一定時間重合し、スチレン系単量体の転化率が８０％から９０％に達した時点で重合工程を完了させる。該重合工程の後、重合温度を所定の温度、好ましくは１００℃以上１２０℃以下に上げ、所定時間熱処理工程を実施することが好ましい。その後、所定の温度まで降温し、発泡剤等を仕込んだ後、再び昇温する。所定の温度、好ましくは１０５℃以上１２０℃以下で一定時間発泡剤含浸工程を実施する。実施後冷却をすると発泡性スチレン系樹脂粒子が得られる。 The production method of expandable styrene resin particles, which is one candidate of the thermoplastic resin that is the substrate used in the present invention, is as follows, for example. A predetermined amount of styrenic monomer and acrylonitrile, a polymerization initiator, and other additives as necessary are added to a predetermined amount of an aqueous suspension medium, and polymerization is performed at a predetermined temperature, preferably 90 ° C. or higher and lower than 100 ° C. for a certain period of time. The polymerization process is completed when the conversion of the styrene monomer reaches 80% to 90%. After the polymerization step, it is preferable to raise the polymerization temperature to a predetermined temperature, preferably 100 ° C. or higher and 120 ° C. or lower, and perform the heat treatment step for a predetermined time. Thereafter, the temperature is lowered to a predetermined temperature, and after charging a foaming agent or the like, the temperature is raised again. The foaming agent impregnation step is performed at a predetermined temperature, preferably 105 ° C. or higher and 120 ° C. or lower for a predetermined time. After cooling, foamable styrene resin particles are obtained.
なお、ビーズ発泡法により方形状の熱可塑性樹脂発泡体を得る方法は、既知の方法を採用することができ、例えば、炭化水素等の発泡剤を含有した発泡性熱可塑性樹脂粒子を回転攪拌式予備発泡装置で、水蒸気、あるいは水蒸気と空気の混合気体を用いて加熱することにより予備発泡粒子を得、得られた予備発泡粒子を方形状の金型内に充填し、水蒸気等を用いて加熱することにより、方形状の発泡体を得ることができる。なお、熱可塑性樹脂発泡体の密度は、予備発泡粒子を得る際の加熱条件で容易に調整することができる。 As a method for obtaining a rectangular thermoplastic resin foam by a bead foaming method, a known method can be adopted. For example, a foaming thermoplastic resin particle containing a foaming agent such as hydrocarbon is rotated and stirred. Pre-foamed particles are obtained by heating with water vapor or a mixed gas of water vapor and air in a pre-foaming device, and the obtained pre-foamed particles are filled in a rectangular mold and heated with water vapor or the like. By doing so, a square-shaped foam can be obtained. In addition, the density of a thermoplastic resin foam can be easily adjusted with the heating conditions at the time of obtaining pre-expanded particle.
なお、予備発泡後の発泡粒子の篩い分けのみならず、予備発泡前においても、呼び寸法６００μｍの網ふるいを通過した発泡性樹脂粒子のみを予備発泡に使用すると、硬芯と呼ばれる、粒子中心付近の未発泡部位がなく、切削性に優れた発泡成形体が得られることから好ましい。 In addition to the sieving of the foamed particles after the pre-foaming, even before the pre-foaming, if only the foamable resin particles that have passed through a screen sieve having a nominal size of 600 μm are used for the pre-foaming, it is called a hard core, near the particle center This is preferable because there is no unfoamed portion and a foamed molded article having excellent machinability is obtained.
本発明の熱可塑性樹脂粒子発泡成形体は、内部に硬芯が存在しないようにすることで、切削加工用として好適に使用することが出来、スライス加工により、厚さ０．１ｍｍ以上１．５ｍｍ以下の発泡フィルムを、収率よく得ることができる。 The thermoplastic resin particle foam molded article of the present invention can be suitably used for cutting by making no hard core inside, and by slicing, the thickness is from 0.1 mm to 1.5 mm The following foamed films can be obtained with good yield.
さらに、本発明は、熱可塑性樹脂発泡体を切削する工程を含んでなるスピーカー用振動板に関するものであり、前記熱可塑性樹脂発泡体を切削する工程は、熱可塑性樹脂発泡体或いは刃の少なくとも一方を往復運動させ、かつ、往路或いは復路の少なくとも一方の工程において熱可塑性樹脂発泡体と刃を摺動させることにより熱可塑性樹脂発泡体を間歇的に切削することを特徴とする。 Furthermore, the present invention relates to a speaker diaphragm comprising a step of cutting a thermoplastic resin foam, and the step of cutting the thermoplastic resin foam includes at least one of a thermoplastic resin foam or a blade. The thermoplastic resin foam is intermittently cut by sliding the thermoplastic resin foam and the blade in at least one of the forward path and the backward path.
具体的には、熱可塑性樹脂発泡体を固定し、往復運動する刃により切削する方法、またはレール上を往復運動する架台に熱可塑性樹脂発泡体を固定し、固定した刃により切削する方法が挙げられる。このように、熱可塑性樹脂発泡体或いは刃の少なくとも一方を往復運動させ、かつ、往路或いは復路の少なくとも一方の工程において熱可塑性樹脂発泡体と刃を摺動させることにより、表面が滑らかであり、中央付近においても厚み精度が高い熱可塑性樹脂発泡フィルムが得られる。更には、熱可塑性樹脂発泡体と刃が摺動する際に、熱可塑性樹脂発泡体の面と刃が平行ではなく角度をなしており、最初に点で接触することが、切削時の熱可塑性樹脂発泡体の毟れを抑制しやすいことから好ましい。当該角度はバイアス角と呼ばれ、５〜８５°であることが好ましい。 Specifically, a method of fixing a thermoplastic resin foam and cutting with a reciprocating blade, or a method of fixing a thermoplastic resin foam on a rack that reciprocates on a rail and cutting with a fixed blade is mentioned. It is done. Thus, the surface is smooth by reciprocating at least one of the thermoplastic resin foam or blade, and sliding the thermoplastic resin foam and blade in at least one step of the forward path or the return path, A thermoplastic resin foam film with high thickness accuracy can be obtained even in the vicinity of the center. Furthermore, when the thermoplastic resin foam and the blade slide, the surface of the thermoplastic resin foam and the blade are not parallel, but at an angle, and the first contact with the point is the thermoplasticity during cutting. It is preferable because it is easy to prevent the resin foam from curling. This angle is called a bias angle and is preferably 5 to 85 °.
なお本発明における、熱可塑性樹脂発泡体または刃の往復運動は、完全に軸上を往復する場合のみならず、一方がクランクギアと連結されるなどにより往復運動に加えて僅かに上下運動を伴う場合も含むものとする。 In addition, the reciprocating motion of the thermoplastic resin foam or blade in the present invention is not only when reciprocating completely on the shaft, but is accompanied by a slight vertical motion in addition to the reciprocating motion by one side being connected to the crank gear. Including cases.
本発明に用いる刃は、得られる発泡フィルムの表面平滑性が高いことから、鋸刃ではなくナイフ刃が好ましい。更には、刃のたわみによる厚み精度低下を回避し得ることから、刃の厚みが３ｍｍ以上であることが好ましい。 The blade used in the present invention is preferably a knife blade instead of a saw blade because the foamed film obtained has high surface smoothness. Furthermore, the thickness of the blade is preferably 3 mm or more because a decrease in thickness accuracy due to the deflection of the blade can be avoided.
また、前記熱可塑性樹脂発泡体と刃の少なくとも一方を往復運動させかつ、往路或いは復路の少なくとも一方の工程において熱可塑性樹脂発泡体と刃を摺動させることにより熱可塑性樹脂発泡体を間歇的に切削する方法においては、熱可塑性樹脂発泡体の密度が１００〜５００ｋｇ／ｍ３であることが好ましい。密度が１００ｋｇ／ｍ３を下回ると厚み精度が損なわれる場合があり、５００ｋｇ／ｍ３を超えると切削時に熱可塑性樹脂発泡フィルムに割れを生じる場合がある。 Further, the thermoplastic resin foam is intermittently moved by reciprocating at least one of the thermoplastic resin foam and the blade and sliding the thermoplastic resin foam and the blade in at least one of the forward path and the return path. In the cutting method, the density of the thermoplastic resin foam is preferably 100 to 500 kg / m 3 . If the density is less than 100 kg / m 3 , the thickness accuracy may be impaired, and if it exceeds 500 kg / m 3 , the thermoplastic foam film may be cracked during cutting.
前記熱可塑性樹脂発泡体と刃の少なくとも一方を往復運動させ、かつ、往路或いは復路の少なくとも一方の工程において熱可塑性樹脂発泡体と刃を摺動させることにより熱可塑性樹脂発泡体を間歇的に切削する方法において、熱可塑性樹脂発泡体と刃に一定荷重を掛け続けることで一往復毎に切削する方法もあるが、一回の切削毎に熱可塑性樹脂発泡体を一定量繰り出し、該繰り出し分を切削する方法が、熱可塑性樹脂発泡フィルム端部の厚み精度が良好なため使用可能な面積が広いことから、好ましい。 The thermoplastic resin foam is intermittently cut by reciprocating at least one of the thermoplastic resin foam and the blade and sliding the thermoplastic resin foam and the blade in at least one of the forward path and the return path. In this method, there is a method in which a constant load is continuously applied to the thermoplastic resin foam and the blade to cut each round, but a certain amount of the thermoplastic foam is fed out for each cutting, The cutting method is preferable because the usable area is wide because the thickness accuracy of the end portion of the thermoplastic resin foam film is good.
熱可塑性樹脂発泡体を切削することで薄片が得られる。この薄片をそのまま本発明の熱可塑性樹脂発泡フィルムとしてもよいが、該薄片はあたかも鉋屑のように巻癖がつき、取扱が困難なものとなる傾向がある。その場合、該薄片を熱可塑性樹脂のガラス転移温度−３０℃以上、かつガラス転移温度以下の温度にて加熱しつつ平板化を行うことが好ましい。ここで、加熱しつつ平板化を行うとは、具体的には、アイロンをかける、２枚の平面板に挟みこんで加熱オーブンに入れる、端部を冶具に固定し軽く外側に延伸しながら加熱など、加熱しながら平面部に一定の応力を与え平板化することを言う。 A flake is obtained by cutting the thermoplastic resin foam. This thin piece may be used as the thermoplastic resin foam film of the present invention as it is, but the thin piece tends to be curled as if it is sawdust and difficult to handle. In that case, it is preferable to perform flattening while heating the thin piece at a glass transition temperature of the thermoplastic resin of −30 ° C. or higher and lower than the glass transition temperature. Here, flattening while heating is, specifically, ironing, sandwiching between two flat plates and placing in a heating oven, heating while fixing the end to a jig and lightly extending outward It refers to flattening by applying a certain stress to the flat part while heating.
前記加熱温度がガラス転移温度−３０℃未満だと巻癖を充分にとることができない場合があり、ガラス転移温度を超えると、熱可塑性樹脂発泡フィルムが更に膨らんだり潰れるなどにより厚み精度が低下する場合がある。なお、加える応力としては、熱可塑性樹脂発泡フィルムが潰れないことから０．１ＭＰａ以下が好ましい。 If the heating temperature is less than the glass transition temperature of −30 ° C., sufficient curling may not be achieved. If the heating temperature exceeds the glass transition temperature, the thermoplastic resin foam film is further swelled or crushed, resulting in a decrease in thickness accuracy. There is a case. The stress to be applied is preferably 0.1 MPa or less because the foamed thermoplastic resin film is not crushed.
また本発明は、熱可塑性樹脂粒子発泡フィルムの少なくとも片面にアルミニウム箔を積層した積層発泡フィルムにも関する。 The present invention also relates to a laminated foam film in which an aluminum foil is laminated on at least one surface of a thermoplastic resin particle foam film.
本発明において熱可塑性樹脂粒子発泡フィルムに積層されるアルミニウム箔は、厚さが０．００５〜０．０５ｍｍであることが好ましく、厚さが０．００７〜０．０２ｍｍであることがより好ましい。厚みが０．００５ｍｍを下回ると積層の際にアルミニウム箔に皺が入る場合があり、厚さが０．０５ｍｍを超えると軽量性が損なわれる場合がある。 In the present invention, the aluminum foil laminated on the thermoplastic resin particle foam film preferably has a thickness of 0.005 to 0.05 mm, and more preferably 0.007 to 0.02 mm. When the thickness is less than 0.005 mm, wrinkles may enter the aluminum foil during lamination, and when the thickness exceeds 0.05 mm, the lightness may be impaired.
本発明において熱可塑性樹脂発泡フィルムにアルミニウム箔を積層する方法に特に制限は無く、接着剤や粘着剤、熱融着などの方法が採用可能だが、生産性や積層複合材の厚み精度の観点から、接着剤による積層が好ましい。 In the present invention, there is no particular limitation on the method of laminating the aluminum foil on the thermoplastic resin foam film, and methods such as adhesives, pressure-sensitive adhesives, and heat fusion can be adopted, but from the viewpoint of productivity and thickness accuracy of the laminated composite material. Lamination with an adhesive is preferred.
前記積層に使用する接着剤としては、無溶剤系で収縮が小さいことが好ましく、エポキシ系接着剤、アクリル系接着剤、シアノアクリレート系接着剤、ウレタン系接着剤、ホットメルト接着剤などが例示される。 The adhesive used for the lamination is preferably solventless and has a small shrinkage, and examples thereof include an epoxy adhesive, an acrylic adhesive, a cyanoacrylate adhesive, a urethane adhesive, and a hot melt adhesive. The
次に、本発明を実施例に基づいて更に詳細に説明するが、本発明はこれら実施例のみに限定されるものではない。 EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples.
〈フィルムの厚み測定〉
厚みゲージを用いて、４５０ｍｍ×３００ｍｍのサンプルについて、サンプル周辺端部３０ｍｍを除いて切り出し、ランダムに３０箇所で厚みを測定し、算術平均により平均厚みを算出すると共に、最大値と最小値の差を算出した。
<Film thickness measurement>
Using a thickness gauge, a sample of 450 mm × 300 mm was cut out except for the sample peripheral edge 30 mm, the thickness was randomly measured at 30 locations, the average thickness was calculated by arithmetic average, and the difference between the maximum value and the minimum value Was calculated.
〈フィルムの密度測定〉
上記熱可塑性樹脂発泡フィルムの厚み測定を行ったサンプルについて、縦横の長さ及び重量を測定し、縦横の長さと平均厚みから体積を算出し、重量を体積で除して算出した。
<Film density measurement>
About the sample which measured the thickness of the said thermoplastic resin foamed film, the length and width were measured, the volume was computed from the length and width and average thickness, and the weight was divided | segmented and calculated.
〈フィルム端部の厚み測定〉
上記熱可塑性樹脂発泡フィルムの厚み測定の際に切り取られた周辺端部について、厚みゲージを用いて、四隅部での厚みを測定し、最小値を端部最小厚みとした。
<Measurement of film edge thickness>
About the peripheral edge part cut off in the case of the thickness measurement of the said thermoplastic resin foam film, the thickness in a four corner part was measured using the thickness gauge, and the minimum value was made into the edge part minimum thickness.
〈フィルムの圧縮強度評価〉
熱可塑性樹脂発泡フィルムを３ｃｍ×３ｃｍに１０枚切り出して重ねて測定試料とし、２３℃雰囲気下、オートグラフを用いて１ｍ／ｍｉｎの速度で圧縮し、変形量が１０％となった際の応力（Ｎ）を試料面積（０．０３ｍ×０．０３ｍ＝０．０００９ｍ２）で除すことにより、１０％圧縮時の圧縮強度を算出した。
<Compressive strength evaluation of film>
Ten sheets of thermoplastic resin foam film cut into 3 cm x 3 cm and stacked to make a measurement sample, compressed at a speed of 1 m / min using an autograph in a 23 ° C atmosphere, and the stress when the deformation amount becomes 10% The compressive strength at 10% compression was calculated by dividing (N) by the sample area (0.03 m × 0.03 m = 0.0009 m 2 ).
〈フィルムの耐熱性評価〉
発泡フィルムの中央部から１００ｍｍ×１００ｍｍのサンプルを切り出し、各辺の長さを測定した後、８５℃に設定した熱風オーブン中にて２時間加熱後に再度測定し、加熱後の長さを加熱前の長さで除して寸法変化の割合を算出した。
<Evaluation of heat resistance of film>
A sample of 100 mm × 100 mm was cut out from the center of the foamed film, the length of each side was measured, and then measured again after heating in a hot air oven set at 85 ° C. for 2 hours, and the length after heating was measured before heating. The ratio of dimensional change was calculated by dividing by the length of.
（実施例１）
株式会社カネカ製の低発泡成形用耐熱発泡性ポリスチレン系樹脂、ヒートマックス（商標）ＨＭ５の内、ＪＩＳ Ｚ８８０１に基づく呼び寸法６００μｍの網ふるいを通過した樹脂だけを取り出し、予備発泡し、再度 呼び寸法５００μｍの網ふるいを通過しない樹脂だけを取り出し成形することにより、４５０ｍｍ×３００ｍｍ×２５ｍｍ、密度２１０ｋｇ／ｍ３の方形状成形体を得た。この方形状発泡体を、以下の切削機を用いて目標厚み０．３ｍｍに設定して切削を行った。
Example 1
Of the heat-resistant foam polystyrene resin for heat-expandable molding made by Kaneka Co., Ltd., HeatMax (trademark) HM5, take out only the resin that passed through a screen sieve with a nominal size of 600μm based on JIS Z8801, pre-foamed, and again nominal size Only a resin that did not pass through a 500 μm mesh sieve was taken out and molded to obtain a rectangular molded body of 450 mm × 300 mm × 25 mm and density 210 kg / m 3 . The rectangular foam was cut using the following cutting machine at a target thickness of 0.3 mm.
使用した切削機は、レール上を床面に平行に往復運動する架台があり、該架台の下部に発泡体を固定し、上向きに固定された刃の上を発泡体が往復することで切削を行い、切削毎、即ち一往復毎に発泡体が目標切削厚み分下がってくることで連続的に切削を行う構成の木材加工用切削機である。なお、バイアス角は１０°に設定した。切削された薄片は巻癖が強く、直径１５ｍｍ程度の巻物状になっていたが、２枚のアルミ板に挟み、１１０℃に設定した熱風オーブン中にて１０分加熱後、放冷して取り出したところ、密度２１０ｋｇ／ｍ３、平均厚み０．３０ｍｍ、最大値と最小値の差は０．０３ｍｍ、端部最小厚みは０．２８ｍｍで、表面の平滑な熱可塑性樹脂粒子発泡フィルムを得た。この発泡フィルムの１０％圧縮時の圧縮強度は４．５ＭＰａであり、樹脂のガラス転移温度は１２２℃であり、耐熱性評価での寸法変化は１．００で変わらなかった。 The cutting machine used has a gantry that reciprocates on the rail parallel to the floor surface. The foam is fixed to the lower part of the gantry, and cutting is performed by the foam reciprocating on the blade fixed upward. This is a woodworking cutting machine configured to perform cutting continuously every time cutting is performed, that is, for each reciprocation, the foam is lowered by a target cutting thickness. The bias angle was set to 10 °. The cut flakes had a strong curl and were in the form of a roll with a diameter of about 15 mm, but were sandwiched between two aluminum plates, heated in a hot air oven set at 110 ° C. for 10 minutes, allowed to cool, and then taken out. The result was a density of 210 kg / m 3 , an average thickness of 0.30 mm, a difference between the maximum and minimum values of 0.03 mm, and a minimum edge thickness of 0.28 mm. . The compression strength of the foamed film at 10% compression was 4.5 MPa, the glass transition temperature of the resin was 122 ° C., and the dimensional change in the heat resistance evaluation was 1.00.
（実施例２）
実施例１で得られた熱可塑性樹脂粒子発泡フィルムの両面に、大日本ホイル製ＶＣコートアルミ箔（塩ビ系粘着剤付きの厚さ０．０１２ｍｍのアルミニウム箔）を貼付したところ、剛性の高い積層発泡フィルムが得られた。
(Example 2)
When both sides of the thermoplastic resin particle foam film obtained in Example 1 were pasted with Dai Nippon Foil VC coated aluminum foil (0.012 mm thick aluminum foil with PVC adhesive), a highly rigid laminate was obtained. A foam film was obtained.
（実施例３）
実施例１の方形状成形体について、実施例１と同じ切削機を用いて目標厚み０．７ｍｍに設定して切削を行い、実施例１と同様にして平板化を行った。
(Example 3)
The rectangular shaped body of Example 1 was cut using the same cutting machine as in Example 1 with a target thickness of 0.7 mm, and flattened in the same manner as in Example 1.
（実施例４）
実施例３で得られた熱可塑性樹脂粒子発泡フィルムに実施例２と同様にして厚さ０．０１２ｍｍのアルミニウム箔を貼付したところ、剛性の高い積層発泡フィルムが得られた。
Example 4
When an aluminum foil having a thickness of 0.012 mm was attached to the thermoplastic resin particle foamed film obtained in Example 3 in the same manner as in Example 2, a highly rigid laminated foamed film was obtained.
（実施例５）
実施例１と同様に、株式会社カネカ製の低発泡成形用耐熱発泡性ポリスチレン系樹脂、ヒートマックス（商標）ＨＭ５の内、ＪＩＳ Ｚ８８０１に基づく呼び寸法６００μｍの網ふるいを通過した樹脂だけを取り出し、予備発泡し、再度 呼び寸法５００μｍの網ふるいを通過しない樹脂だけを取り出し成形することにより、４５０ｍｍ×３００ｍｍ×２５ｍｍ、密度１４０ｋｇ／ｍ３の方形状成形体を得、さらに、実施例１と同様にして目標厚み０．３ｍｍに設定して切削、平板化を行った。
(Example 5)
In the same manner as in Example 1, out of the heat-resistant foaming polystyrene resin for low foam molding manufactured by Kaneka Co., Ltd., Heatmax (trademark) HM5, only the resin that passed through a screen sieve having a nominal size of 600 μm based on JIS Z8801 was taken out. By pre-foaming and again taking out and molding only the resin that does not pass through a net sieve having a nominal size of 500 μm, a rectangular molded body of 450 mm × 300 mm × 25 mm and density of 140 kg / m 3 is obtained. Then, cutting and flattening were performed with the target thickness set to 0.3 mm.
（実施例６）
実施例５で得られた熱可塑性樹脂粒子発泡フィルムに実施例２と同様にして厚さ０．０１２ｍｍのアルミニウム箔を貼付したところ、剛性の高い積層発泡フィルムが得られた。
(Example 6)
When an aluminum foil having a thickness of 0.012 mm was attached to the thermoplastic resin particle foam film obtained in Example 5 in the same manner as in Example 2, a highly rigid laminated foam film was obtained.
（比較例１）
予備発泡の前後で、網ふるいを使用しない以外は、実施例１と同様にして方形状成形体を得、実施例１と同じ切削機を用いて目標厚み０．３ｍｍに設定して切削を行なった結果、切削の段階で、刃こぼれが多発し、刃こぼれしていない部分の発泡フィルムを選別し、実施例１と同様にして平板化を行った。評価結果を表１に示す。得られた熱可塑性樹脂発泡フィルムは、密度２１２ｋｇ／ｍ３、平均厚み０．３ｍｍ、最大値と最小値の差は０．０４ｍｍ、端部最小厚みは０．０５ｍｍで、表面は平滑だが、非常に脆い剛性にも欠ける熱可塑性樹脂発泡フィルムを得た。この発泡フィルムの１０％圧縮時の圧縮強度は４．３ＭＰａであり、耐熱性評価での寸法変化は１．００で変わらなかった。
(Comparative Example 1)
Before and after pre-foaming, a rectangular shaped product was obtained in the same manner as in Example 1 except that no mesh sieve was used, and cutting was performed using the same cutting machine as in Example 1 with a target thickness of 0.3 mm. As a result, at the stage of cutting, blade spilling occurred frequently, and the foamed film in the portion where the blade was not spilled was selected and flattened in the same manner as in Example 1. The evaluation results are shown in Table 1. The obtained thermoplastic resin foam film has a density of 212 kg / m 3 , an average thickness of 0.3 mm, a difference between the maximum value and the minimum value of 0.04 mm, a minimum edge thickness of 0.05 mm, and a smooth surface. A foamed thermoplastic resin film that is also brittle and lacks rigidity was obtained. The compression strength of the foamed film at 10% compression was 4.3 MPa, and the dimensional change in the heat resistance evaluation was 1.00, which was unchanged.
（比較例２）
比較例１で得られた熱可塑性樹脂粒子発泡フィルムに実施例２と同様にして厚さ０．０１２ｍｍのアルミニウム箔を貼付したところ、剛性に欠ける積層発泡フィルムしか得られなかった。
(Comparative Example 2)
When an aluminum foil having a thickness of 0.012 mm was applied to the thermoplastic resin particle foamed film obtained in Comparative Example 1 in the same manner as in Example 2, only a laminated foam film lacking in rigidity was obtained.
（比較例３）
使用する樹脂を、株式会社カネカ製の発泡成形用耐熱発泡性ポリスチレン系樹脂、ヒートマックス（商標）ＨＭに代えた以外は、実施例１と全く同様に方形状成形体を得、実施例１と同様にして切削、平板化を行った。得られた熱可塑性樹脂発泡フィルムは、密度３６ｋｇ／ｍ３、平均厚み０．３１ｍｍ、最大値と最小値の差は０．０６ｍｍと若干大きいが、端部最小厚み０．２８ｍｍの表面の平滑な熱可塑性樹脂発泡フィルムを得た。この発泡フィルムの樹脂のガラス転移温度１１６℃で、耐熱性評価での寸法変化は１．００で変わらなかったが、１０％圧縮時の圧縮強度は０．３ＭＰａであり、剛性に欠ける熱可塑性樹脂粒子発泡フィルムを得た。
(Comparative Example 3)
A rectangular molded body was obtained in the same manner as in Example 1 except that the resin used was changed to Kaneka's heat-resistant foamable polystyrene resin for foam molding, Heatmax (trademark) HM. In the same manner, cutting and flattening were performed. The obtained thermoplastic resin foam film has a density of 36 kg / m 3 , an average thickness of 0.31 mm, and the difference between the maximum value and the minimum value is a little as large as 0.06 mm, but the surface of the end minimum thickness of 0.28 mm is smooth. A thermoplastic resin foam film was obtained. This foamed film resin has a glass transition temperature of 116 ° C., and its dimensional change in heat resistance evaluation was 1.00, but the compression strength at 10% compression was 0.3 MPa, and the thermoplastic resin lacking rigidity. A particle foam film was obtained.
（比較例４）
比較例３で得られた熱可塑性樹脂粒子発泡フィルムに実施例２と同様にして厚さ０．０１２ｍｍのアルミニウム箔を貼付したところ、剛性に欠ける積層発泡フィルムしか得られなかった。
(Comparative Example 4)
When an aluminum foil having a thickness of 0.012 mm was applied to the thermoplastic resin particle foam film obtained in Comparative Example 3 in the same manner as in Example 2, only a laminated foam film lacking in rigidity was obtained.
（比較例５）
実施例１の内、予備発泡後のみ、網ふるいを使用しない以外は、実施例１と全く同様にして、４５０ｍｍ×３００ｍｍ×２５ｍｍ、密度２１０ｋｇ／ｍ３の方形状成形体を得た。さらに、実施例１と同じ切削機を用いて目標厚み０．３ｍｍに設定して切削を行い、実施例１と同様にして平板化を行った。得られた熱可塑性樹脂発泡フィルムは、密度２１０ｋｇ／ｍ３、平均厚み０．３０ｍｍ、最大値と最小値の差は０．０３ｍｍ、端部最小厚みは０．２８ｍｍで、表面の平滑な熱可塑性樹脂粒子発泡フィルムを得たが、収率が低くなった。具体的には、切削工程において、頻繁に硬芯が影響していると思われる刃こぼれが発生し、結果として、傷の無い表面の均一なフィルムは、わずか５０枚しか得られず、さらに、平坦化工程において、フィルム割れが発生し、最終的には、３０枚しか良好なフィルムが得られなかった。実施例１においては、７０枚以上のフィルムが安定的に得られている。こうして得られた傷の無い表面の均一なフィルムの１０％圧縮時の圧縮強度は４．５ＭＰａであり、樹脂のガラス転移温度は１２２℃であり、耐熱性評価での寸法変化は１．００となり、実施例１と同等の結果であった。
(Comparative Example 5)
Of Example 1, only after pre-foaming, a square shaped body having a size of 450 mm × 300 mm × 25 mm and a density of 210 kg / m 3 was obtained in exactly the same manner as Example 1 except that no mesh sieve was used. Further, using the same cutting machine as in Example 1, cutting was performed with the target thickness set to 0.3 mm, and flattening was performed in the same manner as in Example 1. The obtained thermoplastic resin foam film has a density of 210 kg / m 3 , an average thickness of 0.30 mm, a difference between the maximum and minimum values of 0.03 mm, a minimum edge thickness of 0.28 mm, and a smooth thermoplastic surface. A resin particle foam film was obtained, but the yield was low. Specifically, in the cutting process, blade spillage that seems to be frequently affected by the hard core occurs, and as a result, only 50 films with a uniform surface with no scratches can be obtained. In the flattening step, film cracking occurred, and finally only 30 good films were obtained. In Example 1, 70 or more films were stably obtained. The film having a uniform surface having no scratch obtained in this way has a compressive strength at 10% compression of 4.5 MPa, the glass transition temperature of the resin is 122 ° C., and the dimensional change in the heat resistance evaluation is 1.00. The results were the same as in Example 1.
（比較例６）
比較例５で得られた傷の無い表面の均一な熱可塑性樹脂粒子発泡フィルムに実施例２と同様にして厚さ０．０１２ｍｍのアルミニウム箔を貼付したところ、アルミニウム箔の表面に皺が目立つ外観の悪い積層発泡フィルムが得られた。
(Comparative Example 6)
When an aluminum foil having a thickness of 0.012 mm was applied to the uniform foamed thermoplastic resin particle surface of the scratch-free surface obtained in Comparative Example 5 in the same manner as in Example 2, the appearance in which wrinkles were conspicuous on the surface of the aluminum foil was observed. A laminated foam film having a poor thickness was obtained.
実施例１〜６で得られた発泡フィルムおよび積層発泡フィルムを図３に示すような１１ｍｍ×７ｍｍの型で打ち抜き、市販の携帯電話用スピーカーを解体し、スピーカー用振動板の部分を取り替えて評価したところ、良好な音響性能を発現し、十分にスピーカー用振動板として使用可能であることを確認した。
一方で、比較例１〜６で得られたもので、同様にスピーカー用振動板として評価したが、音域の狭い、音圧の低いものしか得られなかった。
実施例１〜６、比較例１〜６の対比により、本発明の効果は明らかである。
The foamed film and laminated foamed film obtained in Examples 1 to 6 were punched with an 11 mm × 7 mm mold as shown in FIG. 3, the commercially available mobile phone speaker was disassembled, and the speaker diaphragm was replaced. As a result, it was confirmed that good acoustic performance was exhibited and it could be sufficiently used as a speaker diaphragm.
On the other hand, it was obtained in Comparative Examples 1 to 6 and was similarly evaluated as a speaker diaphragm, but only a narrow sound range and a low sound pressure were obtained.
The effects of the present invention are clear by comparing Examples 1 to 6 and Comparative Examples 1 to 6.
１ 熱可塑性樹脂発泡体
２ 刃
３ 発泡体を所定量繰り出し可能な架台
DESCRIPTION OF SYMBOLS 1 Thermoplastic resin foam 2 Blade 3 Stand which can pay out predetermined amount of foam
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| JP2009035709A (en) * | 2007-07-10 | 2009-02-19 | Kaneka Corp | Film obtained by extruding and foaming modified polyphenylene ether resin and laminated composite material using the same |
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