JP2008222940A - Persistent antistatic foam - Google Patents

Persistent antistatic foam Download PDF

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Publication number
JP2008222940A
JP2008222940A JP2007066207A JP2007066207A JP2008222940A JP 2008222940 A JP2008222940 A JP 2008222940A JP 2007066207 A JP2007066207 A JP 2007066207A JP 2007066207 A JP2007066207 A JP 2007066207A JP 2008222940 A JP2008222940 A JP 2008222940A
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vinyl acetate
parts
carbon black
ethylene
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JP2007066207A
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Japanese (ja)
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Osamu Yasuda
治 安田
Teruhisa Igai
輝久 猪飼
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YASUDA PLASTIC KK
Sekisui Kasei Co Ltd
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YASUDA PLASTIC KK
Sekisui Plastics Co Ltd
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Priority to JP2007066207A priority Critical patent/JP2008222940A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a packaging material for a liquid crystal panel that has antistatic property due to small surface resistivity, can moderately be deformed so as to wrap the liquid crystal panel therein, has cushioning property (low surface hardness), can hold the liquid crystal panel not to slip on a shock absorbing material, can hold the panel between packaging materials not to shift, and is free from contaminants such as carbon black from the packaging materials and from the deposition on the panel. <P>SOLUTION: This packaging material is produced by foaming a resin mixture comprising an ethylene-vinyl acetate copolymer containing a vinyl acetate component of >20 wt.% and ≤40 wt.% and a conductive carbon black of 10-16 pts.wt. based on the copolymer of 100 pts.wt., and has a surface hardness (C-type hardness tester) of 20-40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、液晶パネルを包装するための緩衝性に優れた包装用材料に好適な持続性帯電防止発泡体に関する。   The present invention relates to a durable antistatic foam suitable for a packaging material having excellent buffering properties for packaging a liquid crystal panel.

従来のカーボンブラックを含む架橋発泡体は、薄いガラス板で構成される液晶パネルの輸送用包装材としては硬度が高く、緩衝性が不足しており輸送中に液晶パネルが破損する問題があった。   The conventional crosslinked foam containing carbon black has high hardness as a packaging material for transporting liquid crystal panels composed of thin glass plates, and there is a problem that the liquid crystal panel is damaged during transportation due to insufficient buffering properties. .

液晶パネルの包装方法としては、輸送用ボックスの中で包装用発泡体の間に液晶パネルを挟んで、緩衝材−パネル−緩衝材−パネル−緩衝材−・・−パネル−緩衝材のように何枚かを積重ねる。液晶パネル(薄いガラス基盤)の包装材として要求される品質は、帯電防止性、緩衝性、柔軟性、非すべり性及び異物が発生しないなどである。すなわち、導電性能まで必要はないが、表面固有抵抗値が小さく、静電気破壊防止、ほこり付着防止等の帯電防止性が備わっている。また液晶パネルを包み込むように適度に変形し、クッション性(表面硬度が低い)、緩衝性、柔軟性に優れる。パネルが緩衝材上で滑らなず、また包装材ではさんだ被包装物がずれないなど、非すべり性が優れている。包装材からの異物発生と付着がない、カーボンブラックが剥離しないなどである。   As a packaging method of the liquid crystal panel, the liquid crystal panel is sandwiched between the foams for packaging in the transport box, and the buffer material-panel-buffer material-panel-buffer material --- panel-buffer material, etc. Stack several pieces. The quality required as a packaging material for a liquid crystal panel (thin glass substrate) includes antistatic properties, buffer properties, flexibility, non-slip properties, and no foreign matter. In other words, although the conductive performance is not required, the surface resistivity is small, and antistatic properties such as prevention of electrostatic breakdown and prevention of dust adhesion are provided. Moreover, it deforms moderately so as to wrap the liquid crystal panel, and is excellent in cushioning properties (low surface hardness), buffering properties and flexibility. The non-slip property is excellent because the panel does not slide on the cushioning material, and the packaged material sandwiched by the packaging material does not slip. There is no generation and adhesion of foreign matter from the packaging material, and carbon black does not peel off.

特許文献1は導電性合成樹脂発泡体及びその製造方法に関し、エチレン−酢酸ビニル共重合体100重量部、導電性カーボンブラック15〜25重量部、その他架橋剤、発泡剤を提示している。
特開平6−136171号
Patent Document 1 relates to a conductive synthetic resin foam and a method for producing the same, and presents 100 parts by weight of an ethylene-vinyl acetate copolymer, 15 to 25 parts by weight of conductive carbon black, other crosslinking agents, and a foaming agent.
JP-A-6-136171

特許文献2は、ポリエチレン0〜100重量%及びエチレン共重合体100〜0重量%からなるポリオレフィン樹脂100重量部、導電性カーボンブラック12〜20重量部、架橋剤0.1〜1.5重量部及び化学発泡剤2〜15重量部からなり、エチレン共重合体として、エチレンを少なくとも60重量%及びビニルアセテート5〜40重量%を含有する単量体混合物からなる共重合体を使用することが記載されている。
特開昭61−197641号
Patent Document 2 discloses a polyolefin resin consisting of 0 to 100% by weight of polyethylene and 100 to 0% by weight of an ethylene copolymer, 12 to 20 parts by weight of conductive carbon black, and 0.1 to 1.5 parts by weight of a crosslinking agent. And 2 to 15 parts by weight of a chemical foaming agent, and as the ethylene copolymer, a copolymer comprising a monomer mixture containing at least 60% by weight of ethylene and 5 to 40% by weight of vinyl acetate is described. Has been.
JP 61-197641 A

特許文献3は導電性発泡体組成物に関し、エチレン−酢酸ビニル共重合体として、酢酸ビニル成分が1〜35重量%が記載されている。
特開昭63−168442号
Patent Document 3 relates to a conductive foam composition, and describes 1 to 35% by weight of a vinyl acetate component as an ethylene-vinyl acetate copolymer.
JP-A 63-168442

しかし特許文献1は帯電防止性能には優れているものの、パネルを包み込むように適度に変形し、表面硬度が低くクッション性にすぐれるというものではなく、液晶パネル用の緩衝材としてはなおクッション性、柔軟性が不十分である。また特許文献2は、大気圧下での架橋発泡であり、さらに高MFRの原料を使用するためセルサイズが大きくなり、外観が劣り、緩衝性に劣る発泡体となりやすい。特許文献3は、帯電防止性能には優れているものの、パネルを包み込むように適度に変形し、表面硬度が低くクッション性にすぐれるというものではなく、液晶パネル用の緩衝材としてはなおクッション性、柔軟性が不十分である。   However, although Patent Document 1 is superior in antistatic performance, it does not deform appropriately so as to wrap the panel, has low surface hardness and excellent cushioning properties, and is still cushioning as a cushioning material for liquid crystal panels. Insufficient flexibility. Further, Patent Document 2 is cross-linked foaming under atmospheric pressure, and further, since a high MFR raw material is used, the cell size becomes large, the appearance is poor, and the foam tends to be inferior in buffering properties. Although Patent Document 3 is excellent in antistatic performance, it is not suitably deformed so as to wrap the panel, has low surface hardness and excellent cushioning properties, and is still cushioning as a cushioning material for liquid crystal panels. Insufficient flexibility.

本発明の目的は、表面固有抵抗値が小さく帯電防止性が備わり、またパネルを包み込むように適度に変形し、クッション性(表面硬度が低い)があり、パネルが緩衝材上で滑らず、また包装材ではさんだ被包装物がずれず、包装材からのカーボンブラック等の異物発生と付着がない持続性帯電防止発泡体、特に液晶パネル用包装材を提供するものである。   The object of the present invention is to have a small surface resistivity, antistatic property, moderate deformation so as to wrap the panel, cushioning property (low surface hardness), the panel does not slide on the cushioning material, and The object of the present invention is to provide a durable antistatic foam, particularly a liquid crystal panel packaging material, in which the packaged material sandwiched by the packaging material does not shift and the generation and adhesion of foreign matters such as carbon black from the packaging material does not occur.

本発明は特定のエチレン−酢酸ビニル共重合体とカーボンブラックとの混合物を架橋発泡させた架橋発泡体からなる持続性帯電防止発泡体である。
すなわち、酢酸ビニル成分が20重量%を超え、40重量%以下であるエチレン−酢酸ビニル共重合体100重量部に対して、導電性カーボンブラック10〜16重量部を含む樹脂混合物を発泡させ、表面硬度(C型硬度計)が20〜40であることを特徴とする持続性帯電防止発泡体である。
The present invention is a durable antistatic foam comprising a crosslinked foam obtained by crosslinking and foaming a mixture of a specific ethylene-vinyl acetate copolymer and carbon black.
That is, a resin mixture containing 10 to 16 parts by weight of conductive carbon black is foamed with respect to 100 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate component of more than 20% by weight and 40% by weight or less. It is a continuous antistatic foam characterized by having a hardness (C-type hardness meter) of 20 to 40.

本発明は、上記により、表面固有抵抗値が小さく帯電防止性が備わり、またパネルを包み込むように適度に変形し、クッション性(表面硬度が低い)があり、パネルが緩衝材上で滑らず、また包装材ではさんだ被包装物がずれず、包装材からのカーボンブラック等の異物発生と付着がない持続性帯電防止発泡体、特に液晶パネル用包装材を提供できる。   As described above, the present invention has a small surface specific resistance value, an antistatic property, is appropriately deformed so as to wrap the panel, has a cushioning property (low surface hardness), the panel does not slide on the cushioning material, In addition, it is possible to provide a durable antistatic foam, particularly a liquid crystal panel packaging material, in which the packaged material sandwiched between the packaging materials does not shift and the generation and adhesion of foreign matters such as carbon black from the packaging material does not occur.

(エチレン−酢酸ビニル共重合体)
本発明に使用される基材樹脂として100重量%のエチレン−酢酸ビニル共重合体を使用する。そして酢酸ビニル成分の含有量が20重量%を超え、40重量%以下のエチレン−酢酸ビニル共重合体である。酢酸ビニル成分が20重量%以下のものでは発泡体の柔軟性が不足する。40重量%を超えるものでは柔らかくなりすぎる。より好ましい含有量は23〜30重量%、さらに好ましくは25〜27重量%である。なお、基材樹脂として必ずしも100重量%でなくてもよく、表面硬度(C型硬度計)が20〜40を満足する範囲内で微量又は少量の低密度ポリエチレン樹脂(LDPE)等他の樹脂が含まれていてもよい。
(Ethylene-vinyl acetate copolymer)
100% by weight of ethylene-vinyl acetate copolymer is used as the base resin used in the present invention. And it is an ethylene-vinyl acetate copolymer whose content of a vinyl acetate component exceeds 20 weight% and is 40 weight% or less. When the vinyl acetate component is 20% by weight or less, the flexibility of the foam is insufficient. If it exceeds 40% by weight, it becomes too soft. A more preferable content is 23 to 30% by weight, and further preferably 25 to 27% by weight. The base resin may not necessarily be 100% by weight, and other resins such as a small amount or a small amount of low density polyethylene resin (LDPE) may be used as long as the surface hardness (C-type hardness meter) satisfies 20 to 40. It may be included.

エチレン−酢酸ビニル共重合体の密度は0.92〜0.97g/cmが好ましく、0.92〜0.95g/cmがより好ましい。またメルトフローレートはカーボンブラックとの混練性、発泡性に優れるため、2.0〜6.0g/10minのエチレン−酢酸ビニル共重合体が好ましい。 Ethylene - Density vinyl acetate copolymer is preferably 0.92~0.97g / cm 3, more preferably 0.92~0.95g / cm 3. In addition, since the melt flow rate is excellent in kneadability and foamability with carbon black, an ethylene-vinyl acetate copolymer of 2.0 to 6.0 g / 10 min is preferable.

前記の密度及びメルトフローレートはJIS K6922で規定された方法で測定されたものである。   The density and the melt flow rate are measured by the method defined in JIS K6922.

(導電性カーボンブラック)
導電性カーボンブラックがエチレン−酢酸ビニル共重合体100重量部に対し、10〜16重量部である。11〜15重量部が好ましく、11〜13重量部がより好ましい。導電性カーボンブラックが10重量部未満であると帯電防止効果がなくなり、導電性カーボンが16重量部より多いと発泡性が低下し、表面硬度が高くなり、パネルを包み込むように適度に変形することがなくなる。また、発泡体からカーボンブラックが分離して被包装物を汚す恐れがある。
(Conductive carbon black)
The conductive carbon black is 10 to 16 parts by weight with respect to 100 parts by weight of the ethylene-vinyl acetate copolymer. 11 to 15 parts by weight is preferable, and 11 to 13 parts by weight is more preferable. When the conductive carbon black is less than 10 parts by weight, the antistatic effect is lost, and when the conductive carbon is more than 16 parts by weight, the foaming property is lowered, the surface hardness is increased, and the panel is appropriately deformed so as to wrap the panel. Disappears. In addition, carbon black may be separated from the foam to contaminate the package.

本発明で使用する導電性カーボンブラックとしては、ファーネスブラック、アセチレンブラック、チャンネルブラック、ケッチェンブラック、サーマルブラック、カーボンナノチューブ等があり、これらは単独で用いても2種類以上を併用しても良い。これらの中では、ケッチェンブラックが好ましい。例えばライオン株式会社製、商品名「ケッチェンブラックEC300J」を用いることができる。   Examples of the conductive carbon black used in the present invention include furnace black, acetylene black, channel black, ketjen black, thermal black, and carbon nanotube. These may be used alone or in combination of two or more. . Of these, ketjen black is preferred. For example, a product name “Ketjen Black EC300J” manufactured by Lion Corporation can be used.

(発泡剤)
本発明で使用し得る発泡剤は、基材となる熱可塑性樹脂の溶融温度以上の分解温度を有する化学発泡剤であれば使用できる。例えば、アゾ系化合物のアゾジカルボンアミド、バリウムアゾジカルボキシレート等:ニトロソ系化合物のジニトロソペンタメチレンテトラミン、トリニトロトリメチルトリアミン等;ヒドラジット系化合物の4,4’−オキシビスベンゼンスルホニルヒドラジッド等;スルホニルセミカルバジッド系化合物の4,4’−オキシビスベンゼンスルホニルセミカルバジッド、トルエンスルホニルセミカルバジッド等を挙げることができる。これらは単独で用いても、二種以上併用してもよい。これらのうち、アゾジカルボンアミドが好ましく、アゾジカルボンアミドとジニトロソペンタメチレンテトラミンを併用することが特に好ましい。
前記発泡剤の使用量は、前記エチレン−酢酸ビニル共重合体からなる樹脂成分100重量部に対し、通常0.5〜15重量部が好ましい。前記発泡剤が前記樹脂成分100重量部に対して0.5重量部未満の場合、発泡倍率が上がらず、15重量部を超えると、良好な発泡体が得られないからである。
(Foaming agent)
As the foaming agent that can be used in the present invention, any chemical foaming agent having a decomposition temperature equal to or higher than the melting temperature of the thermoplastic resin serving as a substrate can be used. For example, azo compounds azodicarbonamide, barium azodicarboxylate, etc .: nitroso compounds dinitrosopentamethylenetetramine, trinitrotrimethyltriamine, etc .; hydragit compounds 4,4′-oxybisbenzenesulfonyl hydrazide, etc .; Examples of the sulfonyl semicarbazide compound include 4,4′-oxybisbenzenesulfonyl semicarbazide and toluenesulfonyl semicarbazide. These may be used alone or in combination of two or more. Of these, azodicarbonamide is preferable, and it is particularly preferable to use azodicarbonamide and dinitrosopentamethylenetetramine in combination.
The amount of the foaming agent used is usually preferably 0.5 to 15 parts by weight with respect to 100 parts by weight of the resin component comprising the ethylene-vinyl acetate copolymer. This is because when the foaming agent is less than 0.5 part by weight relative to 100 parts by weight of the resin component, the foaming ratio does not increase, and when it exceeds 15 parts by weight, a good foam cannot be obtained.

(発泡助剤)
本発明において、発泡助剤を発泡剤の種類に応じて添加することができる。本発明で用い得る前記発泡助剤としては、尿素を主成分とした化合物、酸化亜鉛、酸化鉛等の金属化合物、サリチル酸、ステアリン酸などを主成分とする化合物、即ち高級脂肪酸あるいは高級脂肪酸の金属化合物などがある。その使用量は、前記エチレン−酢酸ビニル共重合体からなる樹脂成分100重量部に対し、通常0.3〜5.0重量部が好ましい。
(Foaming aid)
In the present invention, a foaming aid can be added depending on the type of foaming agent. Examples of the foaming aid that can be used in the present invention include compounds containing urea as a main component, metal compounds such as zinc oxide and lead oxide, compounds containing salicylic acid and stearic acid as main components, that is, higher fatty acids or higher fatty acid metals. There are compounds. The amount used is preferably 0.3 to 5.0 parts by weight per 100 parts by weight of the resin component comprising the ethylene-vinyl acetate copolymer.

(架橋剤)
本発明で用いる架橋剤としては、前記エチレン−酢酸ビニル共重合体からなる樹脂成分の流動開始温度以上の分解温度を有するものであれば使用できる。
(Crosslinking agent)
As a crosslinking agent used by this invention, if it has a decomposition temperature more than the flow start temperature of the resin component which consists of said ethylene-vinyl acetate copolymer, it can be used.

特に、加熱により分解され、遊離ラジカルを発生してその分子間もしくは分子内に架橋結合を生じせしめるラジカル発生剤であるところの有機過酸化物が好ましく、例えばジクミルパーオキサイド、1,1−ジターシャリーブチルパーオキシ−3,3,5−トリメチルシクロヘキサン、2,5−ジメチル−2,5−ジターシャリーブチルパーオキシヘキサン、2,5−ジメチル−2,5−ジターシャリーブチルパーオキシヘキシン、1.3−ビス・ターシャリーブチルパーオキシイソプロピルベンゼン、ターシャリーブチルパーオキシケトン、ターシャリーブチルパーオキシベンゾエートなどを挙げることができる。上記化合物の中でも、1.3−ビス・ターシャリーブチルパーオキシイソプロピルベンゼンが好ましい。   In particular, organic peroxides which are radical generators that decompose by heating and generate free radicals to form crosslinks between or within the molecules are preferred, such as dicumyl peroxide and 1,1-diter. Sharry butyl peroxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-ditertiary butyl peroxyhexane, 2,5-dimethyl-2,5-ditertiary butyl peroxyhexyne, 1 .3-bis tertiary butyl peroxyisopropylbenzene, tertiary butyl peroxyketone, tertiary butyl peroxybenzoate, and the like. Among the above compounds, 1.3-bis tertiary butyl peroxyisopropylbenzene is preferable.

前記架橋剤の使用量は、前記エチレン−酢酸ビニル共重合体からなる樹脂成分100重量部に対し、0.5〜2.0重量部が好ましい。 The amount of the crosslinking agent used is preferably 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the resin component made of the ethylene-vinyl acetate copolymer.

前記架橋剤が0.5重量部未満である場合、架橋が不十分となり、発泡直後の気泡膜強度が不十分でガス抜けしてしまい、発泡体となりにくい。前記架橋剤が2.0重量部を超えると、過剰に架橋し、発泡倍率が上がり難くなる。   When the amount of the crosslinking agent is less than 0.5 parts by weight, the crosslinking is insufficient, the cell membrane strength immediately after foaming is insufficient and the gas escapes, and it is difficult to form a foam. When the cross-linking agent exceeds 2.0 parts by weight, the cross-linking agent is excessively cross-linked and it is difficult to increase the expansion ratio.

(発泡体の製造方法)
発泡方法は、(架橋)常圧発泡法、(架橋)加圧発泡法などの公知の発泡方法が使用できる。
(Method for producing foam)
As the foaming method, a known foaming method such as (crosslinking) atmospheric pressure foaming method or (crosslinking) pressure foaming method can be used.

(架橋)加圧発泡法は、発泡倍率15倍以下の強度のある微細なセルの発泡体が得られやすいことから好ましい方法である。好ましい発泡体の発泡倍率は8〜15倍である。   The (crosslinking) pressure foaming method is a preferred method because it is easy to obtain a fine cell foam having a foaming ratio of 15 times or less. The foaming ratio of a preferable foam is 8 to 15 times.

具体的には、前記のエチレン−酢酸ビニル共重合体と、導電性カーボンブラックとからなる混合物に、架橋剤及び発泡剤、発泡助剤を添加し、例えば単軸押出機、2軸押出機、バンバリーミキサー、加圧型ニーダー、カレンダーロール等の混練装置で架橋剤、発泡剤が分解しない温度及び圧力にて混練して発泡性架橋性組成物を得る。ついで、この発泡性架橋性組成物に架橋を施し、発泡剤を分解温度以上に加熱して発泡させる。前記混練装置としては加圧型ニーダーが好ましい。   Specifically, a cross-linking agent, a foaming agent, and a foaming aid are added to a mixture of the ethylene-vinyl acetate copolymer and conductive carbon black, for example, a single screw extruder, a twin screw extruder, A foamable crosslinkable composition is obtained by kneading with a Banbury mixer, a pressure kneader, a calender roll or the like at a temperature and pressure at which the crosslinking agent and foaming agent are not decomposed. Next, the foamable crosslinkable composition is crosslinked and the foaming agent is heated to a temperature higher than the decomposition temperature to cause foaming. As the kneading apparatus, a pressure type kneader is preferable.

(架橋)加圧発泡法では、発泡性架橋性組成物を密閉系金型に充填し、加圧下に加熱温度120〜160℃、加熱時間20〜70分の条件で加熱し、架橋剤及び発泡剤を完全に分解させ、除圧して、発泡体を得る。 (Crosslinking) In the pressure foaming method, a foamable crosslinkable composition is filled in a closed mold, heated under pressure at a heating temperature of 120 to 160 ° C., and a heating time of 20 to 70 minutes. The agent is completely decomposed and depressurized to obtain a foam.

(発泡体の密度)
本発明に係る発泡体の密度は、60〜200kg/mであることが好ましい。発泡体の密度が60kg/m未満では良好な発泡体とすることができなかったり、強度が不足し、200kg/mを超えると、緩衝性、柔軟性、軽量性や加工性にかける。
(Foam density)
The density of the foam according to the present invention is preferably 60 to 200 kg / m 3 . If the density of the foam is less than 60 kg / m 3 , a good foam cannot be obtained, or the strength is insufficient. If the density exceeds 200 kg / m 3 , the cushioning property, flexibility, lightness and workability are applied.

(表面硬度)
この発泡体の表面硬度(C型硬度計)は20〜40である。表面硬度(C型硬度計)が40を超えるとクッション性、柔軟性が不十分で被包装物が破損する恐れがある。表面硬度(C型硬度計)が20未満では包装体の形態保持性が不十分となり、被包装物が破損する恐れがある。表面硬度が20〜40であることで、クッション性、柔軟性に優れ、被包装物を包み込むように適度に変形し、液晶パネル包装材として保護緩衝性能に優れる。
(surface hardness)
The surface hardness (C-type hardness meter) of this foam is 20-40. If the surface hardness (C-type hardness meter) exceeds 40, the cushioning property and flexibility are insufficient and the packaged product may be damaged. If the surface hardness (C-type hardness meter) is less than 20, the form retainability of the package is insufficient, and the package may be damaged. When the surface hardness is 20 to 40, it is excellent in cushioning properties and flexibility, is appropriately deformed so as to wrap an article to be packaged, and is excellent in protective buffer performance as a liquid crystal panel packaging material.

(表面固有抵抗)
この発泡体の表面固有抵抗は10Ω以上〜1013Ω以下である。10Ω未満となるようなカーボン添加量では発泡体からカーボンが分離して被包装物に付着する恐れがある。1013Ωを超えると帯電防止性能が不足する。
(Surface resistivity)
The surface specific resistance of this foam is 10 8 Ω or more and 10 13 Ω or less. If the amount of carbon added is less than 10 8 Ω, carbon may separate from the foam and adhere to the package. If it exceeds 10 13 Ω, the antistatic performance is insufficient.

かかる持続性帯電防止発泡体、特に液晶パネル用包装材は、帯電防止性を満足し、クッション性、柔軟性を満足し、カーボンブラックの剥離がない外観の良好な発泡体として得られる。   Such a long-lasting antistatic foam, particularly a packaging material for a liquid crystal panel, is obtained as a foam that satisfies antistatic properties, satisfies cushioning properties and flexibility, and has a good appearance with no carbon black peeling.

<実施例1>
表1に記載のように、エチレン−酢酸ビニル共重合体(東ソー株式会社製、商品名「ウルトラセン 634」、酢酸ビニル含有量26重量%、密度0.949g/cm、メルトフローレート4.3g/10min)55.6重量部、導電性カーボンブラックのマスターバッチ(前記エチレン−酢酸ビニル共重合樹体(東ソー株式会社製、商品名「ウルトラセン 634」80重量%と導電性カーボンブラック(ライオン株式会社製、商品名「ケッチェンブラックEC300J」)20重量%からなる)55.5重量部、さらに架橋剤として1,3−ビス(t−ブチルパーオキシイソプロピル)ベンゼン(化薬アクゾ社製、「パーカドックス14R−G」)0.7重量部、発泡剤としてアゾジカルボンアミド(三協化成社製、「セルマイクZ−687」)5.5重量部及びN,N’−ジニトロソペンタメチレンテトラミン(三協化成社製、「セルマイクA」)0.1重量部、発泡助剤として尿素系発泡助剤(三協化成社製、「セルトンNP」)0.4重量部、亜鉛華0.5重量部、ステアリン酸1.0重量部を加え、加圧式ニーダー混練機(トーシン社製、商品名「TD1−5M」)で、温度が115℃になるまで昇温しつつ約15分間混練し、ミキシングロールにてシート状にした。ついで、158℃に加熱されたプレス内の金型(150×150×15mm)に上記シート状混練物を充填し、20分間加圧下で加熱し、除圧後、厚み約30mmの発泡体を得た。なお、カーボンブラックは、EVA樹脂100重量部に対して、11.1重量部になるようにエチレン−酢酸ビニル共重合体およびカーボンブラックのマスターバッチを添加している。
<Example 1>
As shown in Table 1, ethylene-vinyl acetate copolymer (trade name “Ultrasen 634” manufactured by Tosoh Corporation, vinyl acetate content 26% by weight, density 0.949 g / cm 3 , melt flow rate 4. 35.6 parts by weight 55.6 parts by weight, conductive carbon black masterbatch (the ethylene-vinyl acetate copolymer tree (trade name “Ultrasen 634”, manufactured by Tosoh Corporation) and conductive carbon black (Lion 55.5 parts by weight), further comprising 1,3-bis (t-butylperoxyisopropyl) benzene (made by Kayaku Akzo Co., Ltd.) as a crosslinking agent. "Parkadox 14R-G") 0.7 parts by weight, azodicarbonamide as a blowing agent (manufactured by Sankyo Kasei Co., Ltd., "Cermic Z- 87 ") 5.5 parts by weight and 0.1 part by weight of N, N'-dinitrosopentamethylenetetramine (manufactured by Sankyo Kasei Co., Ltd.," Cermic A "), urea foaming aid (Sankyo Kasei) as a foaming aid "Selton NP") 0.4 parts by weight, zinc white 0.5 parts by weight, stearic acid 1.0 parts by weight, pressure kneader kneader (product name "TD1-5M" manufactured by Toshin Co., Ltd.) Then, the mixture was kneaded for about 15 minutes while raising the temperature to 115 ° C. and formed into a sheet with a mixing roll, and then the above-mentioned mold (150 × 150 × 15 mm) in the press heated to 158 ° C. The sheet-like kneaded material was filled, heated under pressure for 20 minutes, and decompressed to obtain a foam having a thickness of about 30 mm.The carbon black was 11.1 parts by weight with respect to 100 parts by weight of the EVA resin. Ethylene-vinyl acetate copolymer And it has been added to the master batch of carbon black.

<実施例2>
表1に記載のように、エチレン−酢酸ビニル共重合体(東ソー株式会社製、商品名「ウルトラセン 634」、酢酸ビニル含有量26重量%、密度0.949g/cm、メルトフローレート4.3g/10min)48重量部、導電性カーボンブラックのマスターバッチ(前記エチレン−酢酸ビニル共重合体(東ソー株式会社製、商品名「ウルトラセン 634」80重量%と導電性カーボンブラック(ライオン株式会社製、商品名「ケッチェンブラックEC300J」)20重量%からなる)65重量部、さらに架橋剤として1,3−ビス(t−ブチルパーオキシイソプロピル)ベンゼン(化薬アクゾ社製、「パーカドックス14R−G」)0.7重量部、発泡剤としてアゾジカルボンアミド(三協化成社製、「セルマイクZ−687」)8.0重量部、発泡助剤として尿素系発泡助剤(三協化成社製、「セルトンNP」)0.7重量部、亜鉛華1.5重量部、ステアリン酸1.0重量部、ステアリン酸亜鉛0.7重量部を加え、加圧式ニーダー混練機(トーシン社製、商品名「TD1−5M」)で、温度が115℃になるまで昇温しつつ約15分間混練し、ミキシングロールにてシート状にした。ついで、158℃に加熱されたプレス内の金型(150×150×15mm)に上記シート状混練物を充填し、20分間加圧下で加熱し、除圧後、厚み約26mmの発泡体を得た。なお、カーボンブラックは、EVA樹脂100重量部に対して、13重量部になるようにエチレン−酢酸ビニル共重合体およびカーボンブラックのマスターバッチを添加している。
<Example 2>
As shown in Table 1, ethylene-vinyl acetate copolymer (trade name “Ultrasen 634” manufactured by Tosoh Corporation, vinyl acetate content 26% by weight, density 0.949 g / cm 3 , melt flow rate 4. 3 g / 10 min) 48 parts by weight, conductive carbon black masterbatch (the ethylene-vinyl acetate copolymer (manufactured by Tosoh Corporation, trade name “Ultrasen 634”) and conductive carbon black (manufactured by Lion Corporation) (Trade name “Ketjen Black EC300J”) 65 parts by weight), and 1,3-bis (t-butylperoxyisopropyl) benzene (manufactured by Kayaku Akzo Corporation, “Parkadox 14R— G ") 0.7 parts by weight, azodicarbonamide as a blowing agent (manufactured by Sankyo Kasei Co., Ltd.," Cermic Z-687 ") 8.0 parts by weight, 0.7 parts by weight of urea-based foaming aid (manufactured by Sankyo Kasei Co., Ltd., “Selton NP”), 1.5 parts by weight of zinc white, 1.0 part by weight of stearic acid, stearin Add 0.7 parts by weight of zinc acid, and knead for about 15 minutes with a pressure kneader kneader (trade name “TD1-5M”, manufactured by Toshin Co., Ltd.) until the temperature reaches 115 ° C. Then, the above-mentioned kneaded material was filled in a die (150 × 150 × 15 mm) in a press heated to 158 ° C., heated under pressure for 20 minutes, and after depressurization, the thickness was about A foam of 26 mm was obtained, and the master batch of ethylene-vinyl acetate copolymer and carbon black was added so that the carbon black was 13 parts by weight with respect to 100 parts by weight of the EVA resin.

<比較例1〜3>
表1の配合で実施例と同様にして発泡体を得た。
<Comparative Examples 1-3>
A foam was obtained in the same manner as in the example with the formulation shown in Table 1.

Figure 2008222940
Figure 2008222940

[表面硬度の測定方法]
表面硬度は、縦50×横50×厚み10以上(mm)の試料を5枚切り出してアスカーゴム・プラスチック硬度計C形(高分子計器(株)製)を用いて測定した。その条件は1kg荷重下30秒後の値を表面硬度とし、5枚の試料の相加平均値を表面硬度とした。
[Measurement method of surface hardness]
The surface hardness was measured using a Asker rubber / plastic hardness meter C type (manufactured by Kobunshi Keiki Co., Ltd.) by cutting out 5 samples of 50 × 50 × 10 (mm) thickness. The condition was that the value after 30 seconds under 1 kg load was the surface hardness, and the arithmetic average value of the five samples was the surface hardness.

[表面固有抵抗(表面抵抗率)の測定方法]
JIS K6911:1995「熱硬化性プラスチック一般試験方法」記載の方法により測定した。即ち、試験装置((株)アドバンテスト製デジタル超高抵抗/微少電流計 R8340及びレジスティビティ・チェンバR12702A)を使用し、試料サンプルに、約30Nの荷重にて電極を圧着させ500V1分間充電後の抵抗値を測定し、次式により算出した。試料サンプルは、100×100×原厚み(10以下)mmとした。
Ps=π(D+d)/(D−d)×Rs
Ps:表面抵抗率(MΩ)
D :表面の環状電極の内径(cm)
d :表面電極の内円の外径(cm)
Rs:表面抵抗(MΩ)
[Measurement method of surface resistivity (surface resistivity)]
Measured by the method described in JIS K6911: 1995 “General Test Method for Thermosetting Plastics”. That is, using a test device (Advantest Co., Ltd. digital ultra-high resistance / microammeter R8340 and resiliency chamber R12702A), an electrode is crimped to a sample sample with a load of about 30 N, and the resistance after charging for 500 V for 1 minute. The value was measured and calculated by the following formula. The sample sample was 100 × 100 × original thickness (10 or less) mm.
Ps = π (D + d) / (D−d) × Rs
Ps: Surface resistivity (MΩ)
D: Inner diameter (cm) of the annular electrode on the surface
d: outer diameter of inner circle of surface electrode (cm)
Rs: Surface resistance (MΩ)

表1により、本発明の実施例は比較例と比べ、表面固有抵抗値が小さく帯電防止性が備わり、またパネルを包み込むように適度に変形し、クッション性(表面硬度が低い)が要求され、パネルが緩衝材上で滑らず、また包装材ではさんだ被包装物がずれず、包装材からのカーボンブラック等の異物発生と付着がない持続性帯電防止発泡体、特に液晶パネル用包装材を提供できる。   According to Table 1, the embodiment of the present invention has a small surface specific resistance value and an antistatic property as compared with the comparative example, and is appropriately deformed so as to wrap the panel, and requires cushioning properties (low surface hardness). Providing long-lasting antistatic foams, especially liquid crystal panel packaging materials, where panels do not slip on cushioning materials, the packaged material sandwiched by packaging materials does not slip, and carbon black and other foreign materials are not generated or adhered to the packaging materials. it can.

本発明は、持続性帯電防止発泡体に適用でき、液晶パネルを包装するための保護緩衝性能に優れた包装用材料に使用できる。   INDUSTRIAL APPLICABILITY The present invention can be applied to a continuous antistatic foam and can be used as a packaging material having excellent protective buffering performance for packaging a liquid crystal panel.

Claims (3)

酢酸ビニル成分が20重量%を超え、40重量%以下であるエチレン−酢酸ビニル共重合体100重量部に対して、導電性カーボンブラック10〜16重量部を含む樹脂混合物を発泡させ、表面硬度(C型硬度計)が20〜40であることを特徴とする持続性帯電防止発泡体。   A resin mixture containing 10 to 16 parts by weight of conductive carbon black is foamed with respect to 100 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate component of more than 20% by weight and 40% by weight or less. A continuous antistatic foam characterized by having a C-type hardness meter) of 20 to 40. 前記エチレン−酢酸ビニル共重合のMFRが2〜6g/10minである請求項1記載の持続性帯電防止発泡体。   The persistent antistatic foam according to claim 1, wherein the MFR of the ethylene-vinyl acetate copolymer is 2 to 6 g / 10 min. 請求項1又は2記載の持続性帯電防止発泡体からなる液晶パネル用包装材。





The packaging material for liquid crystal panels which consists of a durable antistatic foam of Claim 1 or 2.





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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012046240A (en) * 2010-08-30 2012-03-08 Sekisui Plastics Co Ltd Tray for packaging component and packing body using it

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012046240A (en) * 2010-08-30 2012-03-08 Sekisui Plastics Co Ltd Tray for packaging component and packing body using it

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