JPH0461895B2 - - Google Patents
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- Publication number
- JPH0461895B2 JPH0461895B2 JP59051528A JP5152884A JPH0461895B2 JP H0461895 B2 JPH0461895 B2 JP H0461895B2 JP 59051528 A JP59051528 A JP 59051528A JP 5152884 A JP5152884 A JP 5152884A JP H0461895 B2 JPH0461895 B2 JP H0461895B2
- Authority
- JP
- Japan
- Prior art keywords
- particles
- foam
- expandable
- conductive substance
- expandable particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000002245 particle Substances 0.000 claims description 75
- 239000006260 foam Substances 0.000 claims description 23
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 22
- 239000000839 emulsion Substances 0.000 claims description 21
- 239000000126 substance Substances 0.000 claims description 20
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 18
- 239000006229 carbon black Substances 0.000 claims description 14
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 12
- 239000004917 carbon fiber Substances 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 12
- 239000004020 conductor Substances 0.000 claims description 11
- 229920001169 thermoplastic Polymers 0.000 claims description 11
- 229920003023 plastic Polymers 0.000 claims description 8
- 239000004033 plastic Substances 0.000 claims description 8
- 150000001336 alkenes Chemical class 0.000 claims description 6
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 claims description 6
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 229920000620 organic polymer Polymers 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 2
- 239000002984 plastic foam Substances 0.000 claims 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 8
- -1 bromustyrene Chemical compound 0.000 description 5
- 229910002804 graphite Inorganic materials 0.000 description 5
- 239000010439 graphite Substances 0.000 description 5
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- 230000004927 fusion Effects 0.000 description 4
- 229920002681 hypalon Polymers 0.000 description 4
- 239000000178 monomer Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000004604 Blowing Agent Substances 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 3
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 238000006116 polymerization reaction Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 239000004416 thermosoftening plastic Substances 0.000 description 3
- 229920002554 vinyl polymer Polymers 0.000 description 3
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 239000001273 butane Substances 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- KYKAJFCTULSVSH-UHFFFAOYSA-N chloro(fluoro)methane Chemical compound F[C]Cl KYKAJFCTULSVSH-UHFFFAOYSA-N 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 238000004132 cross linking Methods 0.000 description 2
- 229920003020 cross-linked polyethylene Polymers 0.000 description 2
- 239000004703 cross-linked polyethylene Substances 0.000 description 2
- PXBRQCKWGAHEHS-UHFFFAOYSA-N dichlorodifluoromethane Chemical class FC(F)(Cl)Cl PXBRQCKWGAHEHS-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000004794 expanded polystyrene Substances 0.000 description 2
- 238000005187 foaming Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 2
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 229920001909 styrene-acrylic polymer Polymers 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- SBYMUDUGTIKLCR-UHFFFAOYSA-N 2-chloroethenylbenzene Chemical compound ClC=CC1=CC=CC=C1 SBYMUDUGTIKLCR-UHFFFAOYSA-N 0.000 description 1
- 235000004391 Chenopodium capitatum Nutrition 0.000 description 1
- 244000038022 Chenopodium capitatum Species 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- XYLMUPLGERFSHI-UHFFFAOYSA-N alpha-Methylstyrene Chemical compound CC(=C)C1=CC=CC=C1 XYLMUPLGERFSHI-UHFFFAOYSA-N 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- MPMBRWOOISTHJV-UHFFFAOYSA-N but-1-enylbenzene Chemical compound CCC=CC1=CC=CC=C1 MPMBRWOOISTHJV-UHFFFAOYSA-N 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 235000019404 dichlorodifluoromethane Nutrition 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000010097 foam moulding Methods 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
- 239000004702 low-density polyethylene Substances 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- HJWLCRVIBGQPNF-UHFFFAOYSA-N prop-2-enylbenzene Chemical compound C=CCC1=CC=CC=C1 HJWLCRVIBGQPNF-UHFFFAOYSA-N 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Description
本発明は、電磁波吸収材、導電性緩衝材等種々
の用途に利用できる導電特性及び誘電特性にすぐ
れた熱可塑性プラスチツク発泡性粒子及びそれか
らなる発泡体に関するものである。
従来、導電性を有する発泡体としては、(1)カー
ボンブラツクを添加した硬質又は軟質のウレタン
発泡体が実用に供されており、又、(2)スチレン系
樹脂粒子にカーボンブラツクを混合した後ビニル
系モノマーを滴下重合させ、次いで発泡剤を含浸
したスチレン系発泡体や、(3)導電性物質と高分子
化合物エマルジヨンと分散剤を水に分散させた分
散液を予備発泡粒子表面に塗布したポリオレフイ
ン系発泡体が提案されている。
しかし、(1)はカーボンブラツクの添加量に限度
があり、(2)はビニル系モノマーの重合工程を必要
とし、(3)は分散液の濃度、ひいては導電性物質塗
布量に限界がある、等の問題を有している。更
に、かかる方法により得られた発泡体の導電性
は、最良のものでも表面電気抵抗が104Ωのオー
ダーであり、必ずしも種々の使用目的にかなうも
のではない。
又、誘電性を有する発泡体としては、従来、ス
チレン系発泡体表面に墨汁等カーボン系塗料を塗
布したものや発泡フエライト焼結体等が試作され
ているが、性能面及び価格面で必ずしも満足でき
るものではない。
本発明は、かかる実情に鑑み鋭意研究の結果、
熱可塑性プラスチツク予備発泡粒子の表面に、特
定の展着剤を介して黒鉛粉末、カーボンブラツク
及び炭素繊維の混合物を展着することによりすぐ
れた導電性及び誘電性を有する発泡性粒子及びそ
れからなる発泡体を安価に提供するものである。
すなわち、本発明の第１は、熱可塑性プラスチ
ツク発泡粒子の表面に黒鉛粉末、カーボンブラツ
ク及び炭素繊維の混合物からなる導電性物質を展
着してなる導電性及び誘電性を有する発泡性粒
子、本発明の第２は熱可塑性プラスチツク発泡性
粒子を金型内で加熱融着してなる発泡体であつ
て、該発泡体を構成する発泡粒子の表面が黒鉛粉
末、カーボンブラツク及び炭素繊維の混合物から
なる導電性物質により展着された構造の導電性及
び誘電性を有する発泡体を内容とするものであ
る。
本発明で使用する熱可塑性プラスチツクとして
は、スチレン系、オレフイン系プラスチツク等が
あげられる。スチレン系プラスチツクとしては、
スチレン、α−メチルスチレン、エチルスチレ
ン、クロルスチレン、ブロムスチレン、ビニルト
ルエン等の重合体、又はこれらビニル芳香族モノ
マーを50重量％以上含有する共重合体等があげら
れる。スチレン系プラスチツクは粒径0.3〜３mm
の粒子であることが好ましく、常法によりプロパ
ン、ブタン、フロン等の発泡剤を含浸させたもの
を５〜60倍、好ましくは30〜50倍に予備発泡して
用いる。又、オレフイン系プラスチツクとして
は、エチレン、プロピレン、ブテン、ブタジエン
等の重合体、又はこれらオレフイン系モノマーを
50重合％以上含有する共重合体があげられ、これ
らは架橋構造を有していてもさしつかえない。オ
レフイン系プラスチツクの場合粒径0.3〜６mmの
粒子であることが好ましく、常法によりプロパ
ン、ブタン、フロン等の発泡剤を含浸させたもの
を５〜100倍、好ましくは10〜50倍に予備発泡し
て用いる。
本発明で使用する導電性物質としては、黒鉛粉
末、カーボンブラツク及び炭素繊維からなる混合
物が用いられる。
黒鉛粉末は天然、人造のいずれでもよいが鱗片
状のものが好ましく、その粒径は0.1〜50μのもの
が好適に用いられる。カーボンブラツクとしては
一般的なもの、熱処理等の処理を施したもの等を
適宜選択使用できるが、特に〓ケツチエンブラツ
ク（商品名、ライオン・アクゾー株製）〓が好適
である。又、炭素繊維としては直径１〜10μ長さ
0.1〜３mmのものが適当である。黒鉛粉末、カー
ボンブラツク及び炭素繊維の混合比率は特に限定
されないが、重量比で１対１対１〜10対１対１の
範囲が好適である。
導電性物質の展着量は、少な過ぎると導電性能
が不十分となり、反対に多過ぎると成形品密度が
高くなり、又、導電性物質が高価なため経済的で
なくおのずと限界がある。例えばプラスチツク発
泡粒子全表面積１m2当たり６〜30gの範囲が適当
であり、より好ましくは７〜20g、更に好ましく
は７〜15g程度である。
本発明で使用するエマルジヨンとしては有機高
分子エマルジヨンが好適で、例えばアクリル系、
スチレン・アクリル系、酢酸ビニル系、エチレ
ン・酢酸ビニル系等市販のものが用いられる。
導電性物質とエマルジヨンの使用比率は、導電
性物質の比率が大き過ぎると成形品の発泡粒子相
互融着性が悪くなり、反対にエマルジヨン比率が
大き過ぎると導電性能が低下するので、重量比で
３対１〜１対３の範囲（但し、エマルジヨンは固
形分換算）で選択される。
上記の如くして得られた熱可塑性プラスチツク
発泡性粒子を加熱・融着して得られた発泡体は該
発泡体を構成する発泡粒子の表面が上記混合物か
らなる導電性物質により展着された構造からな
る。即ち、該発泡体を形成する粒子の融着面に上
記混合物からなる導電性物質が展着された構造と
なる。
本発明の発泡性粒子は、例えば(1)熱可塑性プラ
スチツク粒子の常法による予備発泡、(2)予備発泡
粒子表面へのエマルジヨンの付着、(3)導電性物質
の展着、(4)乾燥により得られ、発泡体は更に(5)発
泡性粒子の成形用金型への充填と常法による成形
により得られる。
(2)の工程におけるエマルジヨンの付着はミキサ
ー、ブレンダー等を用い、予備発泡粒子上に市販
のエマルジヨンを希釈することなくそのまま滴下
しつつ混合することにより行われる。
(3)の工程はエマルジヨン付着作業の終了後、直
ちに導電性物質を少量ずつ添加し混合することに
より行われる。この工程はエマルジヨンが乾燥固
化する前に、即ち液状である間に、粉末状の導電
性物質を徐々に添加し展着させるもので、外表面
に近いほど導電物質濃度の大きな展着予備発泡粒
子が得られる。黒鉛粉末、カーボンブラツク及び
炭素繊維の混合物からなる混合物は、予めよく混
合しておくのがよい。
(4)の工程はエマルジヨン中の水分を蒸発させ、
エマルジヨン樹脂粒子の保護コロイド膜を破壊し
て連続皮膜を形成させ、導電性物質を予備発泡粒
子表面に強固に接着させるものである。特にこの
工程では、導電性物質を展着した未乾燥予備発泡
粒子を流動、振動、かきまぜ等により動かし解し
つつ乾燥することにより、予備発泡粒子相互のブ
ロツキングを防止することができる。
以下、実施例及び比較例を挙げて本発明をさら
に詳しく説明するが、本発明はこれらにより何ら
制限をうけないことは云うまでもない。
実施例 １
平均粒径0.8mmの球状の発泡ポリスチレン粒子
〔鐘淵化学工業(株)製、商品名〓カネパールGB〓〕
を水蒸気で加熱し、発泡倍率50倍の予備発泡粒子
を得た。
この粒子300gをミキサーに入れ、ミキサーを
回転しつつ、スチレン・アクリル系エマルジヨン
〔カネボウ・エヌエスシー(株)製、商品名〓ヨドゾ
ールGF−１〓、固型分46重量％〕490gを徐々に滴
下し、予備発泡粒子表面にエマルジヨンを付着さ
せた。別に、天然鱗片状黒鉛粉末〔日本黒鉛工業
(株)製、商品名〓CSPE〓粒度範囲１〜15μ〕135g
と〓ケツチエンブラツク〓45g及び炭素繊維〔東
邦レーヨン(株)製、商品名「CFミルドフアイバー」
直径7μ長さ0.2〜0.3mm〕45gを予め混合しておき、
ミキサーを回転しつつ、エマルジヨン付着予備発
泡粒子上に徐々に添加し、導電性物質展着粒子を
得た。この粒子の導電性物質展着量は約8.5g／m2
であつた。
次いで、この粒子をミキサーから取出し、ポリ
エチレンフイルム上にひろげ、ヘラで時々かきま
ぜながら室温下で乾燥させた。５時間後にほぼ乾
燥状態に達し、そのまま一夜放置した。
上記の如くして得られた乾燥粒子を用い、通常
の発泡スチレン成形機により600×370×55mmの板
を成形した。この板は粒子の融着が完全で密度が
49g／であつた。この板の電気抵抗、誘電特
性、圧縮特性、熱伝導率を第１表に示した。
実施例 ２
実施例１の条件のうち、エマルジヨンを酢酸ビ
ニル系〔ダイセル化学工業(株)製、商品名「セビア
ンA22126」、固型分40重量％〕560gに変更した以
外は実施例１と同様にして、粒子の融着が完全で
密度が47g／の板を成形した。この板の電気抵
抗、誘電特性等を第１表に示した。
尚、粒子の導電性物質展着量は実施例１と同じ
であつた。
実施例 ３
導電性物質として、粒径の異なる天然燐片状黒
鉛粉末を３種併用〔日本カーボン(株)製、商品名
「Ｒ−１」粒度範囲１〜44μを45g、日本黒鉛工
業(株)製、商品名「CSPE」粒度範囲１〜15μを
45g、日本黒鉛工業(株)製、商品名「CSSP」粒
度範囲0.1〜5μを45g〕し、これに「ケツチエンブ
ラツク」45g及び「CFミルドフアイバー」45gを
混合したものを用いた以外は実施例１と同様にし
て粒子の融着が完全で密度が50g／の板を成形
した。この板の電気抵抗、誘電特性等を第１表に
示した。
尚、粒子の導電性物質展着量は実施例１と同じ
であつた。
比較例 １
導電性物質として、「CSPE」169gと「ケツチ
エンブラツク」56gを混合使用し炭素繊維は用い
ずにその他の条件を実施例１と同様にして粒子の
融着が完全で密度が43g／の板を成形した。こ
の板の電気抵抗、誘電特性等は第１表のようであ
つた。
尚、粒子の導電性物質展着量は実施例１と同じ
であつた。
比較例 ２
「カネパールGB」を発泡倍率50倍の予備発泡
粒子とし、導電性物質を展着せずに600×370×50
mmの板を成形した。この板は密度が21g／であ
り、電気抵抗、誘電特性は第１表のようであつ
た。
The present invention relates to thermoplastic foam particles having excellent conductive and dielectric properties that can be used for various purposes such as electromagnetic wave absorbers and conductive cushioning materials, and foams made from the same. Conventionally, as conductive foams, (1) hard or soft urethane foams with added carbon black have been put into practical use, and (2) styrene resin particles mixed with carbon black have been used in practical use. A styrene foam impregnated with a blowing agent after dropwise polymerization of a vinyl monomer, and (3) a dispersion of a conductive substance, a polymer compound emulsion, and a dispersant dispersed in water were applied to the surface of the pre-expanded particles. Polyolefin foams have been proposed. However, (1) has a limit on the amount of carbon black added, (2) requires a polymerization process of vinyl monomer, and (3) has a limit on the concentration of the dispersion liquid and, by extension, the amount of conductive material applied. There are other problems. Furthermore, the electrical conductivity of the foam obtained by such a method is such that the surface electrical resistance is on the order of 10 4 Ω at best, and it is not necessarily suitable for various purposes. In addition, as dielectric foams, styrene-based foams coated with carbon-based paints such as Indian ink, and foamed ferrite sintered bodies have been prototyped, but these have not always been satisfactory in terms of performance and price. It's not possible. The present invention has been developed as a result of intensive research in view of the above circumstances.
Expandable particles having excellent conductivity and dielectricity by spreading a mixture of graphite powder, carbon black and carbon fiber on the surface of pre-expanded thermoplastic plastic particles via a specific spreading agent, and foam made from the same. It provides the body at low cost. That is, the first aspect of the present invention is a foamed particle having conductivity and dielectricity, which is formed by spreading a conductive substance consisting of a mixture of graphite powder, carbon black, and carbon fiber on the surface of foamed thermoplastic plastic particles. The second aspect of the invention is a foam formed by heat-sealing expandable thermoplastic plastic particles in a mold, wherein the surface of the expanded particles constituting the foam is made of a mixture of graphite powder, carbon black, and carbon fiber. The content is a foam having conductive and dielectric properties, which has a structure spread with a conductive material. Thermoplastic plastics used in the present invention include styrene plastics, olefin plastics, and the like. As a styrene plastic,
Examples include polymers such as styrene, α-methylstyrene, ethylstyrene, chlorostyrene, bromustyrene, vinyltoluene, and copolymers containing 50% by weight or more of these vinyl aromatic monomers. Styrene plastic has a particle size of 0.3 to 3 mm.
Preferably, the particles are impregnated with a blowing agent such as propane, butane, or chlorofluorocarbon by a conventional method and then pre-expanded to a size of 5 to 60 times, preferably 30 to 50 times. In addition, as olefin plastics, polymers such as ethylene, propylene, butene, butadiene, or these olefin monomers are used.
Examples include copolymers containing 50% or more of polymerization, and these may have a crosslinked structure. In the case of olefin plastic, the particles are preferably 0.3 to 6 mm in diameter, and are impregnated with a blowing agent such as propane, butane, or chlorofluorocarbon by a conventional method, and then pre-foamed to a size of 5 to 100 times, preferably 10 to 50 times. and use it. The conductive material used in the present invention is a mixture of graphite powder, carbon black, and carbon fiber. The graphite powder may be either natural or artificial, but flake-like graphite powder is preferred, and those with a particle size of 0.1 to 50 microns are suitably used. As the carbon black, a general carbon black or a carbon black that has been subjected to treatments such as heat treatment can be selected and used as appropriate, but KETSUCHEN BLACK (trade name, manufactured by Lion Akzo Co., Ltd.) is particularly suitable. Also, carbon fibers have a diameter of 1 to 10μ in length.
A thickness of 0.1 to 3 mm is suitable. The mixing ratio of graphite powder, carbon black and carbon fiber is not particularly limited, but a weight ratio of 1:1:1 to 10:1:1 is suitable. If the amount of the conductive substance spread is too small, the conductive performance will be insufficient, and if it is too large, the density of the molded product will be high, and since the conductive substance is expensive, it is not economical and there is a limit. For example, the amount is suitably in the range of 6 to 30 g, more preferably 7 to 20 g, and even more preferably 7 to 15 g per m 2 of the total surface area of the foamed plastic particles. The emulsion used in the present invention is preferably an organic polymer emulsion, such as acrylic,
Commercially available materials such as styrene/acrylic, vinyl acetate, and ethylene/vinyl acetate are used. The ratio of the conductive substance to the emulsion to be used should be determined based on the weight ratio, because if the ratio of the conductive substance is too large, the mutual fusion of the foamed particles of the molded product will deteriorate, and on the other hand, if the emulsion ratio is too large, the conductive performance will decrease. The ratio is selected in the range of 3:1 to 1:3 (in terms of solid content for emulsions). A foamed product obtained by heating and fusing the thermoplastic foamable particles obtained as described above has a surface of the foamed particles constituting the foamed product that is spread with a conductive substance made of the above mixture. Consists of structure. That is, the foam has a structure in which the conductive material made of the mixture is spread on the fused surfaces of the particles forming the foam. The expandable particles of the present invention can be produced by, for example, (1) pre-foaming thermoplastic particles by a conventional method, (2) adhering an emulsion to the surface of the pre-expanded particles, (3) spreading a conductive substance, and (4) drying. The foam is further obtained by (5) filling expandable particles into a mold and molding by a conventional method. The adhesion of the emulsion in step (2) is carried out by using a mixer, blender, etc., and dropping and mixing a commercially available emulsion as it is without dilution onto the pre-expanded particles. Step (3) is carried out by adding and mixing a conductive substance little by little immediately after the emulsion application process is completed. In this process, before the emulsion is dried and solidified, that is, while it is in a liquid state, a powdered conductive substance is gradually added and spread on the pre-expanded particles, with the concentration of the conductive substance being higher nearer to the outer surface of the emulsion. is obtained. The mixture of graphite powder, carbon black and carbon fibers is preferably mixed well in advance. Step (4) evaporates the water in the emulsion,
The protective colloid film of the emulsion resin particles is destroyed to form a continuous film, and the conductive substance is firmly adhered to the surface of the pre-expanded particles. Particularly in this step, blocking of the pre-expanded particles with each other can be prevented by drying the undried pre-expanded particles on which the conductive substance has been spread while moving and dissolving them by flowing, vibrating, stirring or the like. The present invention will be explained in more detail below with reference to Examples and Comparative Examples, but it goes without saying that the present invention is not limited in any way by these. Example 1 Spherical expanded polystyrene particles with an average particle size of 0.8 mm [manufactured by Kanebuchi Chemical Co., Ltd., trade name: Kanepal GB]
was heated with steam to obtain pre-expanded particles with an expansion ratio of 50 times. 300g of these particles were placed in a mixer, and while the mixer was rotating, 490g of styrene-acrylic emulsion [manufactured by Kanebo NSC Co., Ltd., trade name: Yodozol GF-1, solid content: 46% by weight] was gradually added dropwise. Then, the emulsion was attached to the surface of the pre-expanded particles. Separately, natural flaky graphite powder [Nippon Graphite Industries
Manufactured by Co., Ltd., product name: CSPE, particle size range: 1 to 15μ, 135g
45g of Ketsuchen Black and carbon fiber [manufactured by Toho Rayon Co., Ltd., product name: "CF Milled Fiber"]
Mix 45g of diameter 7μ and length 0.2~0.3mm in advance.
While rotating the mixer, it was gradually added onto the emulsion-attached pre-expanded particles to obtain conductive substance-spread particles. The amount of conductive material spread on these particles is approximately 8.5g/m 2
It was hot. The particles were then removed from the mixer, spread on a polyethylene film, and dried at room temperature while occasionally stirring with a spatula. It reached a nearly dry state after 5 hours, and was left as it was overnight. Using the dry particles obtained as described above, a plate of 600 x 370 x 55 mm was molded using an ordinary styrene foam molding machine. This board has perfect particle fusion and high density.
It was 49g/. The electrical resistance, dielectric properties, compression properties, and thermal conductivity of this plate are shown in Table 1. Example 2 Same as Example 1 except that the emulsion was changed to 560 g of vinyl acetate type [manufactured by Daicel Chemical Industries, Ltd., trade name "Sevian A22126", solid content 40% by weight]] A plate with complete fusion of particles and a density of 47 g/ was molded. The electrical resistance, dielectric properties, etc. of this plate are shown in Table 1. The amount of conductive material spread on the particles was the same as in Example 1. Example 3 Three types of natural scaly graphite powders with different particle sizes were used in combination as conductive substances [Nippon Carbon Co., Ltd., trade name "R-1", 45 g of particle size range 1 to 44μ, Nippon Graphite Industries Co., Ltd. ), product name "CSPE" particle size range 1-15μ
45g, manufactured by Nippon Graphite Industries Co., Ltd., trade name "CSSP" particle size range 0.1 to 5μ], mixed with 45g of "Ketsutien Black" and 45g of "CF Milled Fiber" were used. A plate with complete particle fusion and a density of 50 g/m was molded in the same manner as in Example 1. The electrical resistance, dielectric properties, etc. of this plate are shown in Table 1. The amount of conductive material spread on the particles was the same as in Example 1. Comparative Example 1 A mixture of 169 g of "CSPE" and 56 g of "Ketschen Black" was used as the conductive material, and the other conditions were the same as in Example 1 without using carbon fiber, so that the particles were completely fused and the density was 43 g. A plate of / was molded. The electrical resistance, dielectric properties, etc. of this plate were as shown in Table 1. The amount of conductive material spread on the particles was the same as in Example 1. Comparative example 2 "Kanepal GB" is used as pre-expanded particles with a foaming ratio of 50 times, and the size is 600 x 370 x 50 without spreading a conductive substance.
A plate of mm was formed. This plate had a density of 21 g/, and its electrical resistance and dielectric properties were as shown in Table 1.
【表】
実施例 ４
密度0.924g／cm3、MI値1.5、平均粒径1.3mmの低
密度ポリエチレン粒子をパーオキサイド架橋によ
り架橋度50％の架橋ポリエチレンとした後、60℃
の飽和フロン12（CCl2F2）ガス中に60分放置して
フロン12を含浸させた。この架橋発泡性ポリエチ
レン粒子を水蒸気で加熱し、発泡倍率35倍の予備
発泡粒子を得た。
この粒子300gをミキサーに入れ、ミキサーを
回転しつつ、スチレン・アクリル系エマルジヨン
〔カネボウ・エヌエスシー(株)製、商品名〓ヨドゾ
ールGF−１〓、固型分46重量％〕490gを徐々に滴
下し、予備発泡粒子表面にエマルジヨンを付着さ
せた。別に、天然鱗片状黒鉛粉末〔日本黒鉛工業
(株)製、商品名〓CSPE〓粒度範囲１〜15μ〕135g
と〓ケツチエンブラツク〓45g及び炭素繊維〔東
邦レーヨン(株)製、商品名「CFミルドフアイバー」
直径7μ長さ0.2〜0.3mm〕45gを予め混合しておき、
ミキサーを回転しつつ。エマルジヨン付着予備発
泡粒子上に徐々に添加し、導電性物質展着粒子を
得た。この粒子の導電性物質展着量は約8.5g／m2
であつた。
次いで、この粒子をミキサーから取出し、ポリ
エチレンフイルム上にひろげ、ヘラで時々かきま
ぜながら室温下で乾燥させた。５時間後にほぼ乾
燥状態に達し、そのまま一夜放置した。
上記の如くして得られた乾燥粒子を用い、通常
の発泡ポリスチレン成形機により600×370×50mm
の板を成形した。この板は粒子の融着が完全で密
度が60g／であつた。この板の電気抵抗、誘電
特性、圧縮特性、熱伝導率を第２表に示した。
比較例 ３
実施例４の架橋ポリエチレン予備発泡粒子を用
い、導電性物質を展着せずに密度が32g／の板
を成形した。
この板の電気抵抗、誘電特性等は第２表の通り
であつた。[Table] Example 4 Low-density polyethylene particles with a density of 0.924 g/cm 3 , an MI value of 1.5, and an average particle size of 1.3 mm were made into cross-linked polyethylene with a degree of cross-linking of 50% by peroxide cross-linking, and then heated at 60°C.
The sample was left in saturated Freon 12 (CCl 2 F 2 ) gas for 60 minutes to impregnate it with Freon 12. The cross-linked foamable polyethylene particles were heated with steam to obtain pre-expanded particles with an expansion ratio of 35 times. 300g of these particles were placed in a mixer, and while the mixer was rotating, 490g of styrene-acrylic emulsion [manufactured by Kanebo NSC Co., Ltd., trade name: Yodozol GF-1, solid content: 46% by weight] was gradually added dropwise. Then, the emulsion was attached to the surface of the pre-expanded particles. Separately, natural flaky graphite powder [Nippon Graphite Industries
Manufactured by Co., Ltd., product name: CSPE, particle size range: 1 to 15μ, 135g
45g of Ketsuchen Black and carbon fiber [manufactured by Toho Rayon Co., Ltd., product name: "CF Milled Fiber"]
Mix 45g of diameter 7μ and length 0.2~0.3mm in advance.
While the mixer is running. It was gradually added onto the emulsion-adhered pre-expanded particles to obtain conductive substance-spread particles. The amount of conductive material spread on these particles is approximately 8.5g/m 2
It was hot. The particles were then removed from the mixer, spread on a polyethylene film, and dried at room temperature while occasionally stirring with a spatula. It reached a nearly dry state after 5 hours, and was left as it was overnight. Using the dry particles obtained as described above, a size of 600 x 370 x 50 mm was molded using a normal expanded polystyrene molding machine.
A plate was formed. In this plate, the particles were completely fused and the density was 60 g/. The electrical resistance, dielectric properties, compression properties, and thermal conductivity of this plate are shown in Table 2. Comparative Example 3 Using the crosslinked polyethylene pre-expanded particles of Example 4, a plate having a density of 32 g/m was molded without spreading a conductive substance. The electrical resistance, dielectric properties, etc. of this plate were as shown in Table 2.
Claims (1)
鉛粉末、カーボンブラツク及び炭素繊維の混合物
からなる導電性物質を展着してなる発泡性粒子。 ２ 熱可塑性プラスチツクがスチレン系又はオレ
フイン系プラスチツクである特許請求の範囲第１
項記載の発泡性粒子。 ３ 導電性物質の展着量が6g／m2以上である特
許請求の範囲第１項記載の発泡性粒子。 ４ 体積抵抗が103Ω・cm未満かつ表面抵抗が103
Ω未満である特許請求の範囲第１項記載の発泡性
粒子。 ５ 比誘電率が３以上かつ誘電損失が0.2以上で
ある特許請求の範囲第１項記載の発泡性粒子。 ６ 展着剤が有機高分子エマルジヨンである特許
請求の範囲第１項記載の発泡性粒子。 ７ 熱可塑性プラスチツク発泡性粒子を金型内で
加熱融着してなる発泡体であつて、該発泡体を構
成する発泡粒子の表面が黒鉛粉末、カーボンブラ
ツク及び炭素繊維の混合物からなる導電性物質に
より展着された構造の発泡体。 ８ 熱可塑性プラスチツクがスチレン系又はオレ
フイン系プラスチツクである特許請求の範囲第７
項記載の発泡体。 ９ 導電性物質の展着量が6g／m2以上である特
許請求の範囲第７項記載の発泡体。 １０ 体積抵抗が103Ω・cm未満かつ表面抵抗が
103Ω未満である特許請求の範囲第７項記載の発
泡体。 １１ 比誘電率が３以上かつ誘電損失が0.2以上
である特許請求の範囲第７項記載の発泡体。 １２ 展着剤が有機高分子エマルジヨンである特
許請求の範囲第７項記載の発泡体。[Scope of Claims] 1. Expandable particles formed by spreading a conductive substance made of a mixture of graphite powder, carbon black, and carbon fibers on the surface of expandable thermoplastic plastic particles. 2 Claim 1 in which the thermoplastic plastic is a styrene-based or olefin-based plastic
Expandable particles as described in section. 3. The expandable particles according to claim 1, wherein the spread amount of the conductive substance is 6 g/m 2 or more. 4 Volume resistance is less than 10 3 Ω・cm and surface resistance is 10 3
The expandable particles according to claim 1, wherein the expandable particles are less than Ω. 5. The expandable particles according to claim 1, which have a relative dielectric constant of 3 or more and a dielectric loss of 0.2 or more. 6. The expandable particles according to claim 1, wherein the spreading agent is an organic polymer emulsion. 7 A foam made by heat-sealing expandable thermoplastic plastic particles in a mold, where the surface of the foamed particles constituting the foam is a conductive material made of a mixture of graphite powder, carbon black, and carbon fibers. A foam with a structure expanded by. 8 Claim No. 7 in which the thermoplastic plastic is a styrene-based or olefin-based plastic
Foam as described in Section. 9. The foam according to claim 7, wherein the amount of the conductive substance spread is 6 g/m 2 or more. 10 Volume resistivity is less than 10 3 Ω・cm and surface resistance is
8. The foam of claim 7, which has a resistance of less than 10 3 Ω. 11. The foam according to claim 7, which has a dielectric constant of 3 or more and a dielectric loss of 0.2 or more. 12. The foam according to claim 7, wherein the spreading agent is an organic polymer emulsion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59051528A JPS60195134A (en) | 1984-03-16 | 1984-03-16 | Electrically-conductive thermoplastic plastic expandable particle and foam consisting thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59051528A JPS60195134A (en) | 1984-03-16 | 1984-03-16 | Electrically-conductive thermoplastic plastic expandable particle and foam consisting thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60195134A JPS60195134A (en) | 1985-10-03 |
| JPH0461895B2 true JPH0461895B2 (en) | 1992-10-02 |
Family
ID=12889513
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59051528A Granted JPS60195134A (en) | 1984-03-16 | 1984-03-16 | Electrically-conductive thermoplastic plastic expandable particle and foam consisting thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60195134A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4235693C1 (en) * | 1992-10-22 | 1994-07-14 | Hein Farben Gmbh | Process for flame retardant treatment of polyolefin particle foams |
| JPH1041674A (en) * | 1996-07-24 | 1998-02-13 | Mitsubishi Cable Ind Ltd | Wave absorber and manufacture thereof |
| JP4789307B2 (en) * | 2000-06-23 | 2011-10-12 | 旭化成ケミカルズ株式会社 | Functional polyolefin resin expanded particles and in-mold molded articles thereof |
| JP6247459B2 (en) * | 2013-06-14 | 2017-12-13 | 旭化成株式会社 | Foamed particles and foamed particle molded body |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52130868A (en) * | 1976-04-23 | 1977-11-02 | Reuter Technologie Gmbh | Molded conductive foam |
| JPS5889624A (en) * | 1981-11-24 | 1983-05-28 | Karitasu Kogyo Gijutsu Kaihatsu Center:Kk | Manufacture of polystyrene foam molded product capable of preventing and eliminating static electricity |
| JPS5892540A (en) * | 1981-11-30 | 1983-06-01 | Fujimori Kogyo Kk | Conductive foam molding body and manufacture therefor |
-
1984
- 1984-03-16 JP JP59051528A patent/JPS60195134A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52130868A (en) * | 1976-04-23 | 1977-11-02 | Reuter Technologie Gmbh | Molded conductive foam |
| JPS5889624A (en) * | 1981-11-24 | 1983-05-28 | Karitasu Kogyo Gijutsu Kaihatsu Center:Kk | Manufacture of polystyrene foam molded product capable of preventing and eliminating static electricity |
| JPS5892540A (en) * | 1981-11-30 | 1983-06-01 | Fujimori Kogyo Kk | Conductive foam molding body and manufacture therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60195134A (en) | 1985-10-03 |
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