針對上述本發明,以下更詳細地進行說明。 <1>本發明之透明導電性封裝膠帶之層構成 圖1係表示本發明之透明導電性封裝膠帶之概略性剖視圖。 圖2係表示將本發明之透明導電性封裝膠帶作為蓋材並與載帶熱密封之狀態之一例之概略性剖視圖。 如圖1所示,本發明之透明導電性封裝膠帶係經由接著劑層2將中間層3貼合於基材膜1,並於其上積層熱密封層4而成者。此處,中間層3係包含藉由共擠出法一併製膜第一中間層3a與第二中間層3b而成之共擠出膜。 再者,藉由共擠出法而進行之製膜與如貼合僅為單體膜之層壓製法等不同,係將熔融後之複數種樹脂自複數個較細之狹縫狀之間隙擠出而進行。 因此,藉由共擠出而形成之層間之界面顯示出極其特異之結構,該結構與藉由層壓製法之自黏等交聯相互作用所形成之層間結構大不相同。 具體而言,認為藉由共擠出而形成之界面形成各樹脂之結晶相互滲入之互鎖結構,具有極其複雜之結構。 因此,於本發明中,有僅憑表述為藉由共擠出法而成膜之層而對中間層加以特定之方法,即,可僅憑藉由製造方法所產生之物體之特定而表述本發明之特徵。 於將本發明之透明導電性封裝膠帶應用作載帶之蓋材時,以熱密封層4之面對向之方式將本發明之封裝膠帶重合並熱密封於載帶5之袋部6上。 <2>基材膜 於本發明中,基材膜可使用使包含聚對苯二甲酸乙二酯(PET)、聚萘二甲酸乙二酯等聚酯、聚丙烯等聚烯烴、尼龍等聚醯胺、聚碳酸酯等熱塑性樹脂之膜沿一軸或二軸方向延伸而成之膜。 該等可單獨使用,或亦可藉由任意之積層方法將同種或異種之2種或2種以上之膜積層後使用。 就顯示出適合封裝膠帶之透明性、耐熱性及耐濕性之方面而言,可尤佳地使用PET膜。 為了強化與接著劑層之接著強度,亦可視需要對與接著劑層相接之側之表面預先實施電暈放電處理、電漿處理、噴砂處理等表面處理。 又,為了防止垃圾或灰塵向表面之附著或防止與其他面之接觸所導致之靜電之產生,亦可視需要使用界面活性劑、離子液體、導電性聚合物、導電性碳黑、金屬蒸鍍、金屬氧化物等導電性微粒子等對與和接著劑層相接之側相反之面即最外面實施抗靜電處理。 基材膜之厚度可由業者適當地設定,就對封裝膠帶賦予適當之強度或韌性之目的而言,例如為3~25 μm。 <3>接著劑層 經由接著劑層將中間層貼合於基材膜之一面。此處,作為接著劑,可使用任意之乾式層壓用接著劑。 作為乾式層壓用接著劑,可使用1液或2液硬化型之乙烯系、(甲基)丙烯酸系、聚醯胺系、聚酯系、聚醚系、聚胺基甲酸酯系、環氧系、橡膠系等溶劑型、水性型、或乳膠型等之層壓用接著劑。 又,接著劑之塗佈可為凹版塗佈、輥塗等,不論其方法如何均可。 接著劑層之厚度可適當調整,例如為了對封裝膠帶賦予適度之剛性,為1~10 g/m2
,較佳為2~5 g/m2
。若薄於1 g/m2
,則無法使接著強度均勻,又,無法縮小剝離強度最大差值而使之具有穩定所需之剛性。 又,若厚於10 g/m2
,則於價格方面不利,不僅如此,亦存在剛性變得過強而導致封裝膠帶產生龜裂之情況。 <4>中間層 於本發明中,中間層係位於基材膜與熱密封層之間之層,並且係包含藉由共擠出法製膜第一中間層與第二中間層而成之膜。 第一中間層係位於基材膜側之層。該層對封裝膠帶賦予緩衝性,確保與載帶之密封強度,同時經由接著劑層與基材膜達成較高之層間接著強度。 進而,亦為承擔內襯支持第二中間層之作用而提高共擠出製膜時之製膜穩定性之層。 於本發明中,第一中間層係包含聚乙烯系樹脂。 此處,作為聚乙烯系樹脂,可列舉利用丙烯酸、甲基丙烯酸、順丁烯二酸酐、反丁烯二酸等不飽和羧酸對直鏈狀(線狀)低密度聚乙烯、高壓法低密度聚乙烯、中密度聚乙烯、高密度聚乙烯、聚丙烯、乙烯-乙酸乙烯酯共聚物、離子聚合物樹脂、乙烯-丙烯酸乙酯共聚物、乙烯-丙烯酸共聚物、乙烯-甲基丙烯酸共聚物、乙烯-丙烯共聚物、進而甲基戊烯聚合物、聚乙烯、聚乙烯系樹脂或者聚丙烯系樹脂等聚烯烴系樹脂進行改性而成之酸改性聚烯烴系樹脂或該等之2種或2種以上之混合物等。 為了確保密封強度、充分地發揮提高製膜穩定性之功能,又,對封裝膠帶賦予良好之柔軟性及透明性,尤佳為使用直鏈狀低密度聚乙烯。 於本發明中,直鏈狀低密度聚乙烯係使用茂金屬觸媒等單點觸媒或齊格勒-納塔觸媒等多點系觸媒,使乙烯與碳數3~20之α-烯烴於低溫、低壓下共聚合而獲得之共聚物。 作為碳數3~20之α-烯烴,具體而言,可列舉:丙烯、1-丁烯、1-戊烯、4-甲基-1-戊烯、1-己烯、1-辛烯、1-壬烯、1-癸烯、1-十二烯等。 又,作為共聚合方法,可列舉利用低壓法、漿料法、溶液法、氣相法等使乙烯及α-烯烴聚合之方法。 第一中間層可為1層,亦可包含特性不同之2層以上。例如,於第一中間層使用直鏈狀低密度聚乙烯之情形時,亦可包含靠近基材層之側之密度相對較高且捲取性優異之包含直鏈狀低密度聚乙烯之第一中間層A與靠近第二中間層之側之密度相對較低且柔軟之包含直鏈狀低密度聚乙烯之第一中間層B。 藉由第一中間層A而發揮良好之捲取性,藉由第一中間層B而發揮緩衝性,藉此可達成捲取性與緩衝性之兼顧。 為了發揮適當之緩衝性,第一中間層與第二中間層所使用之聚乙烯系樹脂層之密度較佳為0.900 g/cm3
以上、0.940 g/cm3
以下,第一中間層所使用之聚乙烯系樹脂層之密度更佳為0.910 g/cm3
以上、0.930 g/cm3
以下。尤其是第一中間層B所使用之聚乙烯系樹脂層之密度較佳為0.910 g/cm3
以上、0.915 g/cm3
以下。 若樹脂之密度高於上述範圍,則於熱密封於載帶時,有作為中間層之緩衝性容易降低、對載帶表面形狀之追隨性容易變差、與載帶之密接強度(剝離強度)容易降低、剝離時之剝離強度最大差值容易增大之傾向。 若樹脂密度低於上述範圍,則有熱密封於載帶時之經熔融之樹脂之流動性容易變得過強,故而經熔融之樹脂容易自封裝膠帶端擠出而污染熱密封治具之烙鐵,或於以中間層積層膜之狀態捲取保管時容易產生貼附而容易導致處理變難之傾向。 第二中間層係位於熱密封層側之層。該層係與熱密封層發揮穩定之層間接著強度並有助於密封性與易剝離性之兼顧之層。 於本發明中,第二中間層係包括包含乙烯・α-烯烴共聚物與苯乙烯・丁二烯嵌段共聚物之樹脂組合物。 此處,作為乙烯・α-烯烴共聚物,可使用關於上述第一中間層而列舉之直鏈狀低密度聚乙烯。 藉由使用上述直鏈狀低密度聚乙烯,透明性提高,與聚苯乙烯、苯乙烯・丁二烯嵌段共聚物之摻合比對應之剝離強度之控制變得容易。 又,作為構成苯乙烯・丁二烯嵌段共聚物之苯乙烯系單體,例如可列舉:苯乙烯、氯苯乙烯、氯甲基苯乙烯、第三丁基苯乙烯、乙烯基甲苯等。 又,作為可與該等共聚合之單體,除丁二烯以外,亦可包含異戊二烯、丙烯腈、甲基丙烯腈等。 除苯乙烯・丁二烯嵌段共聚物以外,亦可包含聚苯乙烯、耐衝擊性聚苯乙烯、苯乙烯・丁二烯接枝共聚物、苯乙烯與異戊二烯之嵌段或接枝共聚物、丙烯腈・丁二烯・苯乙烯共聚物或該等之2種或2種以上之混合物等。 可尤其適當地使用使苯乙烯50~90質量%與丁二烯50~10質量%共聚合而成之苯乙烯・丁二烯嵌段共聚物。 於樹脂組合物中,若源自聚苯乙烯系樹脂及苯乙烯之單元之比率過多,則有透明性降低,另一方面,層間之密接性增高而易剝離性降低之傾向。又,於與第一中間層共擠出時,有製膜性降低之傾向。 形成第二中間層之樹脂組合物可藉由調整乙烯・α-烯烴共聚物與苯乙烯・丁二烯嵌段共聚物之摻合比而控制與熱密封層之層間接著強度,並兼顧所需之易剝離性及密封性。 此處,兩者之摻合比可根據所使用之苯乙烯・丁二烯嵌段共聚物中之源自苯乙烯之單元之含量與所需之密封強度(剝離強度)等由業者適當地調整。 為了自與第一中間層及下述熱密封層之平衡中獲得適合作為封裝膠帶之密封強度及易開封性,第二中間層較佳為具有70~110℃、更佳為82℃以上、例如82~85℃之維卡軟化點。 為了獲得此種第二中間層,形成第二中間層之樹脂組合物例如係將乙烯・α-烯烴共聚物30~70質量%與苯乙烯・丁二烯嵌段共聚物70~30質量%摻合而成。 作為兩者之摻合比,更佳為相對於乙烯・α-烯烴共聚物50~70質量%而苯乙烯・丁二烯嵌段共聚物為50~30質量%,進而較佳為相對於乙烯・α-烯烴共聚物55~70質量%而苯乙烯・丁二烯嵌段共聚物為45~30質量%,兩者之合計為100質量%。 若超過上述範圍、苯乙烯含量較少、維卡軟化點過高,則層之柔軟性不足而有損密封性及層間之密接性。反之,若苯乙烯含量較多、維卡軟化點過低,則剝離強度最大差值增大而有損易剝離性。 再者,於本發明中,維卡軟化點係基於JISK7206之A120法而測定之值。 第一及第二中間層之厚度之合計為15~50 μm,更佳為20~45 μm。若中間層整體之厚度過薄,則無法發揮充分之緩衝性且無法確保密封強度。 又,製膜變得不穩定而無法製膜均勻之膜。反之,若過厚,則必須提高密封溫度並延長密封時間以確保密封強度,從而欠佳。 又,第二中間層之厚度為2~20 μm,更佳為5~15 μm。若第二中間層過薄,則密封強度降低,從而欠佳。反之,若過厚,則於中間層製膜時容易產生褶皺或偏厚、針孔,從而欠佳。 形成第一及第二中間層之膜係藉由利用膨脹法、T模法等慣用之膜製膜法將2層共擠出而形成。 再者,藉由共擠出法而進行之製膜與如貼合僅為單體膜之層壓製法等不同,係將熔融後之複數種樹脂自複數個較細之狹縫狀之間隙擠出而進行。 為了提高與接著劑層及熱密封層之接著強度,亦可視需要預先對膜之表面實施電暈放電處理、電漿處理、噴砂處理等表面處理。 又,第一及第二中間層亦可於不損及發明之效果之範圍內視需要包含任意之添加劑。 作為此種添加劑,可使用為了調整樹脂膜之成形加工性或生產性、各種物性而通常使用之各種樹脂用添加劑。但是,就對透明性、層間密接性及易剝離性等之影響而言,不包含導電性微粒子等粒子。 <5>熱密封層 於本發明中,熱密封層係包含使導電性微粒子分散於丙烯酸系樹脂中而成之透明導電性熱密封材。 就易剝離性、熱密封性及黏連性之方面而言,透明導電性熱密封材較佳為具有20~100℃、更佳為具有30~60℃之玻璃轉移點。若玻璃轉移點過低,則熱密封層變柔軟而有損塗膜形成性及易剝離性。反之,若玻璃轉移點過高,則熱密封層變硬而無法獲得充分之密封強度。 再者,於本發明中,玻璃轉移點係依據JISK7121所測得之值。 於本發明中,丙烯酸系樹脂包含丙烯酸系單體之均聚物及共聚物。作為丙烯酸系單體,例如可列舉:(甲基)丙烯酸甲酯、(甲基)丙烯酸乙酯、(甲基)丙烯酸丙酯、(甲基)丙烯酸正丁酯、(甲基)丙烯酸異丁酯等。其中,所謂(甲基)丙烯酸酯,係指丙烯酸酯或甲基丙烯酸酯。 又,作為可與該等共聚合之單體,可列舉:苯乙烯系單體例如苯乙烯、氯苯乙烯、氯甲基苯乙烯、第三丁基苯乙烯、乙烯基甲苯等。 具體而言,可列舉:聚(甲基)丙烯酸甲酯、聚(甲基)丙烯酸乙酯、聚(甲基)丙烯酸丁酯、(甲基)丙烯酸甲酯-(甲基)丙烯酸丁酯共聚物、(甲基)丙烯酸甲酯與苯乙烯之無規、嵌段或接枝共聚物、(甲基)丙烯酸乙酯與苯乙烯之無規、嵌段或接枝共聚物等。就塗膜形成性等之方面而言,可尤佳地使用與苯乙烯之共聚物。 丙烯酸酯與苯乙烯之共聚物中之苯乙烯含有率可根據形成第二中間層之樹脂及所需之易剝離性而由業者適當地決定,例如苯乙烯含有率為0~30質量%,更佳為0~20質量%。 若苯乙烯含有率過高,則玻璃轉移點降低,可能會有損塗膜形成性及易剝離性。反之,於苯乙烯含有率較少之情形時,存在難以形成均質之塗膜之情形。 藉由使用該等丙烯酸系樹脂作為熱密封材之黏合劑而達成所需之熱密封性或易剝離性,不僅如此,例如即便於使用尤佳之PET膜作為基材膜之情形時,亦可防止黏連之產生。 又,於本發明中,分散於丙烯酸系樹脂中之導電性微粒子係表面塗佈有摻雜有銻之氧化錫之硫酸鋇粒子或二氧化矽粒子或摻雜有銻之氧化錫之針狀粒子。 摻雜有銻之氧化錫係藉由利用離子摻雜法利用銻原子取代氧化錫分子上之氧原子而獲得。 於本發明中,可適當地使用以體積電阻率成為500 Ω・m以下、較佳為100 Ω・m以下之方式將該摻雜有銻之氧化錫塗佈於硫酸鋇粒子或二氧化矽粒子上而成之微粒子或包含該摻雜有銻之氧化錫之針狀粒子。 藉由將摻雜有銻之氧化錫塗佈於微粒子上後使用,可獲得廉價且均勻之微小粉末。尤其是於塗佈於折射率被設為1.6左右之硫酸鋇粒子或折射率被設為1.5左右之二氧化矽粒子上之情形時,藉由將成為核之粒子之平均粒徑設為0.3 μm以下、更佳為0.2 μm以下、進而0.1 μm以下,粒子不會使可見光擴散,故而可確保較高之透明性。 藉由使用針狀之摻雜有銻之氧化錫,可以較少之添加量獲得較高之導電性,且可確保較高之透明性。 於本發明中,作為適當使用之針狀粒子之粒子尺寸,平均長度(平均長徑)為100~2000 nm,更佳為200~2000 nm。又,平均長度(平均長徑)/平均直徑(平均短徑)之縱橫比為10以上,較佳為20~30。 再者,於本發明中,將摻雜有銻之氧化錫塗佈於硫酸鋇粒子或二氧化矽粒子上而成之微粒子之平均粒徑係由體積累積分佈表示藉由雷射繞射散射法所測得之粒徑分佈時之50%粒徑(d50中徑),針狀之摻雜有銻之氧化錫之平均長度及平均直徑係藉由利用電子顯微鏡(SEM)進行觀察並對任意30個進行測定所得之平均值。 使用塗佈有摻雜有銻之氧化錫之硫酸鋇粒子或二氧化矽粒子或摻雜有銻之氧化錫之針狀粒子作為導電性微粒子,並使其分散於丙烯酸系樹脂中,藉此以少量之導電性微粒子達成較高之抗靜電特性。因此,可將熱密封層設定為較薄,又,無損透明性。 進而,於與聚苯乙烯製或聚碳酸酯製載帶進行熱密封時,可與第一及第二中間層之作用相輔相成而達成良好之密封強度及剝離強度,從而可兼顧優異之密封性與易剝離性。 關於丙烯酸系樹脂與上述導電性微粒子之質量比,相對於丙烯酸系樹脂100質量份,導電性微粒子為10~400質量份。 若導電性微粒子之量多於上述範圍,則塗膜之透明性變差,從而欠佳。另一方面,若導電性微粒子之量少於上述範圍,則無法獲得所需之抗靜電性能,從而欠佳。 就透明性、密封性及抗靜電效果之觀點而言,熱密封層之厚度較佳為0.1~5 μm、尤其是0.2~2 μm之範圍。於本發明中,熱密封層係包含上述丙烯酸系樹脂與塗佈有摻雜有銻之氧化錫之硫酸鋇粒子或二氧化矽粒子或針狀之摻雜有銻之氧化錫之組合,故而即便使層厚較薄,亦可獲得充分之抗靜電效果。 於本發明中,關於熱密封層,其表面電阻率於22℃、40% RH下為105
~1012
Ω/□之範圍內。又,於23±5℃、12±3% RH下,自5000 V衰減99%所需之電荷衰減時間為1秒以下,而具有優異之靜電特性。 若上述表面電阻率超過1012
Ω/□,則靜電擴散效果變得極差,而難以保護電子零件免受靜電破壞,又,若未達105
Ω/□,則可能會自外部經由蓋材對電子零件通電,而有電子零件受到電破壞之危險性。 另一方面,於作為藉由靜電而產生之電荷之擴散速度之標準之電荷衰減時間超過1秒之情形時,靜電擴散效果變得極差,而難以保護電子零件免受靜電破壞。 再者,上述表面電阻率及電荷衰減時間可依據作為美國之軍用標準之MIL-B-81705C進行測定。 可視需要使熱密封層含有分散穩定劑、界面活性劑、抗黏連劑等添加劑。 熱密封層可藉由凹版塗佈法、氣刀塗佈法、刮刀塗佈(blade coating)法、刮刀塗(knife coating)法、桿式塗佈法、直接輥式塗佈法、逆輥塗佈法、斜板式塗佈法、孔縫式塗佈法等塗佈方法塗佈形成於第二中間層上。 <6>導電性封裝膠帶 如上述之本發明之封裝膠帶具有總光線透過率成為70%以上且霧度值成為30%以下般之透明性。更佳為總光線透過率為75%以上且霧度值為25%以下,尤佳為總光線透過率為80%以上且霧度值為23%以下。 因此,使用本發明之封裝膠帶之編帶包裝體可自封裝膠帶之上,於未開封之狀態下藉由目視或相機檢查來檢查、確認有無內容物、填充狀態等。 並且,本發明之封裝膠帶具有於自載帶開封時,於密封部,於第二中間層與熱密封層之層間產生剝離(層間剝離),而不會受熱密封層與載帶之熱融合條件影響之穩定之剝離性能。該剝離強度(層間接著強度)弱於熱密封層與載帶之剝離強度,較佳為100~1200 gf/15 mm之範圍。 若剝離強度變得未達100 gf/15 mm,則有於包裝體之傳輸及保管中產生剝離而內容物脫落之危險性。又,若剝離強度超過1200 gf/15 mm,則有於將封裝膠帶剝離時載帶振動而導致內容物飛出之情況,從而欠佳。 再者,於本發明中,剝離強度係23℃、相對濕度40%之環境下之180度剝離(剝離速度300 mm/min)之值。 又,剝離強度最大差值較佳為30 gf/1 mm以下。若剝離強度最大差值超過50 gf/1 mm,則有於將封裝膠帶剝離時載帶振動而導致內容物飛出之虞,從而欠佳。 再者,所謂此處所言之剝離強度最大差值,係指使用2條寬為0.5 mm之熱密封條將封裝膠帶與載帶進行熱密封,並將其剝離時之剝離強度之最大值與最小值之差。 剝離強度最大差值之測定條件係於23℃、相對濕度40%之環境下以剝離速度300 mm/min之條件將測定長度20 mm進行180度剝離時之數值。 作為應用本發明之封裝膠帶之載帶之材質,為聚氯乙烯、聚苯乙烯、聚酯、聚丙烯、聚碳酸酯、聚丙烯腈、ABS(Acrylonitrile Butadiene Styrene,丙烯腈-丁二烯-苯乙烯共聚物)等,尤佳為聚苯乙烯及聚碳酸酯。 又,亦可為於該等樹脂中混練導電性碳黑微粒子、金屬微粒子、使金屬氧化物具有導電性之導電性微粒子、有機矽化合物或者界面活性劑作為抗靜電對策或者塗佈有包含該等者之材質。 繼而,列舉與導電性微粒子之類型對應之實施例對本發明具體地進行說明。 [實施例] <實驗I> [實施例1] 藉由共擠出製膜包含密度0.925之直鏈狀低密度聚乙烯(Prime Polymer(股)製造之EVOLUE SP2520)之第一中間層(厚度20 μm)、及包括包含密度0.919之直鏈狀低密度聚乙烯(Prime Polymer(股)製造之ULT-ZEX 2021L)60質量%與苯乙烯・丁二烯嵌段共聚物(Asahi Kasei Chemicals(股)製造之Asaflex 810,苯乙烯含有率65質量%)40重量%之樹脂組合物(維卡軟化點85℃)之第二中間層(厚度10 μm),獲得總厚度30 μm之膜。 隔著包含多元醇與硬化劑之接著劑層對該膜之第一中間層之面與厚度12 μm之雙軸延伸PET膜(東洋紡織(股)製造之E7415單面抗靜電・單面電暈處理類型)之電暈處理面進行乾式層壓。 繼而,藉由輥式塗佈法將使導電性微粒子(表面塗佈有摻雜有銻之氧化錫之硫酸鋇粒子,平均粒徑0.25 μm)240質量份分散於丙烯酸系樹脂(甲基丙烯酸甲酯等之共聚物)100質量份中而成之透明導電性熱密封材(玻璃轉移點50℃)以厚度2 μm塗佈於所獲得之積層體之第二中間層之面,而製造本發明之封裝膠帶。 針對所獲得之封裝膠帶,於以下之條件下測定表面電阻率、電荷衰減時間、霧度值、總光線透過率、剝離強度、及剝離強度最大差值。 (表面電阻率) 於22℃、40% RH下,使用三菱化學ANALYTECH(股)製造之Hiresta UP以探針URS、施加電壓10 V進行測定。 (電荷衰減時間) 於23±5℃、12±3% RH下,依據MIL-B-81705C,並利用ETS公司(Electro-Tech Systems,Inc)製造之STATIC DECAY METER-406C測定自5000 V衰減99%所需之時間。 (霧度值及總光線透過率) 依據JIS K7136及JIS K7361並使用東洋精機製作所(股)製造之Haze-gard II進行測定。 (剝離強度) 於150℃、0.5秒、3.0 kgf/cm2
之條件下將所獲得之封裝膠帶熱密封於聚苯乙烯基材,繼而,於23℃、40% RH下,利用東洋baldwin(股)製造之Tensilon萬能試驗機HTH-100測定剝離強度。(剝離速度=300 mm/min,180°剝離) (剝離強度最大差值) 使用2條寬0.5 mm之熱密封條於150℃、0.4秒、3.0 kgf之條件下將所獲得之封裝膠帶熱密封於聚苯乙烯製載帶,繼而,於23℃、40% RH下,利用Vanguard Systems(股)製造之剝離強度測試機VG-20測定剝離強度(剝離速度=300 mm/min,測定長度20 mm,180°剝離),求出最大值與最小值之差。 將測定結果示於下述表1。 [表1]
實施例中所製造之本發明之封裝膠帶具有適當之表面電阻率,且電荷衰減時間充分短,故而具有優異之靜電特性,可良好地保護電子零件免受靜電破壞等。又,具有較高之透明性,即便藉由相機檢查亦可容易地確認內容物之狀態。 進而,具有良好之剝離強度,一面將內容物充分地密封,一面保持易開封性。尤其是剝離強度之剝離強度最大差值較小,可獲得極其順暢之剝離感。 [實施例2] 使用二氧化矽粒子代替硫酸鋇粒子作為導電性微粒子之芯材,除此以外,以與實施例1相同之方式製造本發明之封裝膠帶。所獲得之封裝膠帶顯示出與實施例1之封裝膠帶相同之性質。 [實施例3] 使用包含該直鏈狀低密度聚乙烯80質量%與該苯乙烯・丁二烯嵌段共聚物20重量%之樹脂組合物作為第二中間層,除此以外,以與實施例1相同之方式製造本發明之封裝膠帶。所獲得之封裝膠帶顯示出適宜之表面電阻率及靜電特性,剝離強度雖適宜,但小於實施例1,而密封性略差。 [比較例1] 使用無銻氧化錫粉末作為導電性微粒子,並使用使該氧化錫粉末240質量份分散於該丙烯酸系樹脂100質量份中而成之熱密封材,除此以外,以與實施例1相同之方式製造封裝膠帶。 所獲得之封裝膠帶與實施例之封裝膠帶相比,表面電阻率較大,電荷衰減時間較長,而靜電擴散效果較差。 [比較例2] 使用厚度30 μm之聚乙烯膜代替包含第一及第二中間層之共擠出膜,除此以外,以與實施例1相同之方式製造封裝膠帶。所獲得之封裝膠帶與實施例之封裝膠帶相比,熱密封層與中間層之間之層間接著強度較小,密封性較差。 <實驗IIA> [實施例1] 藉由共擠出製膜包含密度0.925之直鏈狀低密度聚乙烯(Prime Polymer(股)製造之EVOLUE SP2520)之第一中間層(厚度20 μm)、及包括包含密度0.919之直鏈狀低密度聚乙烯(Prime Polymer(股)製造之ULT-ZEX 2021L)60質量%與苯乙烯・丁二烯嵌段共聚物(Asahi Kasei Chemicals(股)製造之Asaflex 810,苯乙烯含有率65質量%)40重量%之樹脂組合物(維卡軟化點85℃)之第二中間層(厚度10 μm),獲得總厚度30 μm之膜。 隔著包含多元醇與硬化劑之接著劑層對該膜之第一中間層之面與厚度12 μm之雙軸延伸PET膜(東洋紡織(股)製造之E7415單面抗靜電・單面電暈處理類型)之電暈處理面進行乾式層壓。 繼而,藉由輥式塗佈法將使導電性微粒子(摻雜有銻之氧化錫之針狀粒子,石原產業(股)製造之FS-10P)210質量%分散於苯乙烯-甲基丙烯酸酯共聚物100質量%中而成之透明導電性熱密封材(玻璃轉移點50℃)以厚度2 μm塗佈於所獲得之積層體之第二中間層之面,製造本發明之封裝膠帶。 針對所獲得之封裝膠帶,於以下之條件下測定表面電阻率、電荷衰減時間、霧度值、總光線透過率、剝離強度、及剝離強度最大差值。 將測定結果示於下述表2。 [表2]
[實施例2] 使用包含該直鏈狀低密度聚乙烯80質量%與該苯乙烯・丁二烯嵌段共聚物20重量%之樹脂組合物作為第二中間層,除此以外,以與實施例1相同之方式製造本發明之封裝膠帶。所獲得之封裝膠帶顯示出適宜之表面電阻率及靜電特性,剝離強度雖適宜,但小於實施例1,而密封性略差。 [實施例3] 使用包含直鏈狀低密度聚乙烯(Prime Polymer(股)製造之ULT-ZEX UZ2022L,密度0.919 g/cm3
)55質量%與該苯乙烯・丁二烯嵌段共聚物45重量%之樹脂組合物作為第二中間層,除此以外,以與實施例1相同之方式製造本發明之封裝膠帶。所獲得之封裝膠帶顯示出與實施例1同等之性能。 [實施例4] 使用包含直鏈狀低密度聚乙烯(Prime Polymer(股)製造之ULT-ZEX UZ2022L,密度0.919 g/cm3
)80質量%與該苯乙烯・丁二烯嵌段共聚物20重量%之樹脂組合物作為第二中間層,除此以外,以與實施例1相同之方式製造本發明之封裝膠帶。所獲得之封裝膠帶顯示出與實施例1同等之表面電阻率及靜電特性,剝離強度雖適宜,但略小於實施例1,而密封性略差。 [實施例5] 使用包含直鏈狀低密度聚乙烯(Prime Polymer(股)製造之EVOLUE SP2020,密度0.916 g/cm3
)60質量%與該苯乙烯・丁二烯嵌段共聚物40重量%之樹脂組合物作為第二中間層,除此以外,以與實施例1相同之方式製造本發明之封裝膠帶。所獲得之封裝膠帶顯示出與實施例1同等之性能。 [比較例1] 使用無銻氧化錫粉末作為導電性微粒子,並使用使該導電性微粒子210質量%分散於該苯乙烯-甲基丙烯酸酯共聚物100質量%中而成之熱密封材,除此以外,以與實施例1相同之方式製造封裝膠帶。所獲得之封裝膠帶與實施例之封裝膠帶相比,表面電阻率較大,電荷衰減時間較長,而靜電擴散效果較差。 [比較例2] 使用厚度30 μm之聚乙烯膜代替包含第一及第二中間層之共擠出膜,除此以外,以與實施例1相同之方式製造封裝膠帶。所獲得之封裝膠帶與實施例之封裝膠帶相比,熱密封層與中間層之間之層間接著強度較小,而密封性較差。 <實驗IIB> [實施例1] 藉由共擠出製膜包含直鏈狀低密度聚乙烯1(Prime Polymer(股)製造之EVOLUE SP2020,密度0.916 g/cm3
)之第一中間層A(厚度7.5 μm)、包含直鏈狀低密度聚乙烯3(Prime Polymer(股)製造之EVOLUE SP1520,密度0.913 g/cm3
)之第一中間層B(厚度12.5 μm)、及包含樹脂組合物2B1(含有55質量%之直鏈狀低密度聚乙烯1、45重量%之苯乙烯・丁二烯嵌段共聚物1(Asahi Kasei Chemicals(股)製造之Asaflex 810,苯乙烯含有率65質量%)之混合物,維卡軟化點85℃)之第二中間層(厚度10 μm),獲得總厚度30 μm之膜。 隔著包含多元醇與硬化劑之2液硬化型胺基甲酸酯接著劑層對該膜之第一中間層之面與厚度12 μm之雙軸延伸PET膜1(東洋紡織(股)製造之E7415單面抗靜電・單面電暈處理類型)之電暈處理面進行乾式層壓。 繼而,藉由輥式塗佈法將透明導電性熱密封材2B1(含有68質量%之導電性微粒子1(石原產業(股)製造之FS-10P,摻雜有銻之氧化錫之針狀粒子)、32質量%之苯乙烯-甲基丙烯酸酯共聚物之混合物,玻璃轉移點50℃)以厚度1 μm塗佈於所獲得之積層體之第二中間層之面作為密封層,而製造本發明之封裝膠帶。 針對所獲得之封裝膠帶,於以下之條件下測定表面電阻率、電荷衰減時間、霧度值、總光線透過率、剝離強度、及剝離強度最大差值。 所獲得之封裝膠帶顯示出適宜之表面電阻率及靜電特性、剝離強度。 [實施例2] 使用樹脂組合物2B2(含有60質量%之直鏈狀低密度聚乙烯3、40質量%之苯乙烯・丁二烯嵌段共聚物1之混合物,維卡軟化點85℃)作為第二中間層,除此以外,以與實施例1相同之方式製造本發明之封裝膠帶。 所獲得之封裝膠帶顯示出適宜之表面電阻率及靜電特性、剝離強度。 [比較例1] 使用直鏈狀低密度聚乙烯2(Prime Polymer(股)製造之EVOLUE SP2520,密度0.925 g/cm3
)作為第一中間層A,無第一中間層B,使用樹脂組合物2B3(含有55質量%之直鏈狀低密度聚乙烯4(Prime Polymer(股)製造之ULT-ZEX UZ2022L,密度0.919 g/cm3
)、45重量%之苯乙烯・丁二烯嵌段共聚物1之混合物)作為第二中間層,使用透明導電性熱密封材2B2(含有68質量%之導電性微粒子2(無銻之氧化錫之針狀粒子)、32質量%之苯乙烯-甲基丙烯酸酯共聚物1之混合物)作為密封層,除此以外,以與實施例1相同之方式製造本發明之封裝膠帶。 所獲得之封裝膠帶顯示出表面電阻率非常高、電荷衰減時間非常長、電特性較差之結果。 [比較例2] 使用直鏈狀低密度聚乙烯2作為第一中間層A,無第一中間層B,使用直鏈狀低密度聚乙烯4作為第二中間層,除此以外,以與實施例1相同之方式製造本發明之封裝膠帶。 所獲得之封裝膠帶顯示出剝離強度非常低、無法測定剝離強度最大差值、密接性較差之結果。 [表3] The present invention will be described in more detail below. <1> Layer structure of the transparent conductive packaging tape of the present invention FIG. 1 is a schematic cross-sectional view showing the transparent conductive packaging tape of the present invention. 2 is a schematic cross-sectional view showing an example of a state in which the transparent conductive sealing tape of the present invention is used as a cover material and is heat-sealed with a carrier tape. As shown in FIG. 1, the transparent conductive packaging tape of the present invention is obtained by bonding an intermediate layer 3 to a base film 1 through an adhesive layer 2 and laminating a heat-sealing layer 4 thereon. Here, the intermediate layer 3 includes a co-extruded film formed by co-extrusion of the first intermediate layer 3a and the second intermediate layer 3b. Furthermore, the film formation by the co-extrusion method is different from the lamination method such as laminating only a monomer film, which extrudes a plurality of melted resins from a plurality of thin slit-shaped gaps. Go out. Therefore, the interface between the layers formed by coextrusion shows a very specific structure, which is very different from the interlayer structure formed by cross-linking interactions such as self-adhesion by the lamination method. Specifically, it is considered that an interlocking structure in which crystals of each resin penetrate into each other through an interface formed by co-extrusion has an extremely complicated structure. Therefore, in the present invention, there is a method of specifying the intermediate layer only by expressing it as a layer formed by a co-extrusion method, that is, the present invention can be expressed only by the specificity of an object produced by a manufacturing method. Characteristics. When the transparent conductive sealing tape of the present invention is applied as a cover material of a carrier tape, the sealing tape of the present invention is recombined and heat-sealed on the bag portion 6 of the carrier tape 5 with the heat-sealing layer 4 facing away. <2> Base film In the present invention, the base film can be made of a polymer including polyester such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefin such as polypropylene, and nylon. Films made of thermoplastic resins such as amines and polycarbonates are stretched along one or two axes. These can be used alone, or two or more kinds of the same kind or different kinds can be laminated by any lamination method and used. In terms of showing transparency, heat resistance, and moisture resistance suitable for a packaging tape, a PET film can be particularly preferably used. In order to strengthen the bonding strength with the adhesive layer, surface treatments such as corona discharge treatment, plasma treatment, and sand blasting treatment may also be performed on the surface in contact with the adhesive layer in advance as necessary. In addition, in order to prevent the adhesion of garbage or dust to the surface or the generation of static electricity caused by contact with other surfaces, surfactants, ionic liquids, conductive polymers, conductive carbon black, metal evaporation, Conductive fine particles such as metal oxides are subjected to antistatic treatment to the outermost surface, which is the side opposite to the side where the adhesive layer is in contact. The thickness of the base film can be appropriately set by the supplier, and for the purpose of imparting appropriate strength or toughness to the sealing tape, it is, for example, 3 to 25 μm. <3> The adhesive layer is bonded to one surface of the base film through the adhesive layer. Here, as the adhesive, any adhesive for dry lamination can be used. As the adhesive for dry lamination, one- or two-component hardened vinyl, (meth) acrylic, polyamide, polyester, polyether, polyurethane, or cyclic Solvent-based, water-based, or latex-type laminating adhesives such as oxygen-based and rubber-based adhesives. The application of the adhesive may be gravure coating, roll coating, or the like, regardless of the method. The thickness of the adhesive layer can be appropriately adjusted, for example, in order to impart moderate rigidity to the sealing tape, it is 1 to 10 g / m 2 , Preferably 2 to 5 g / m 2 . If thinner than 1 g / m 2 , The adhesive strength cannot be made uniform, and the maximum difference in peel strength cannot be reduced to make it rigid enough to stabilize. Also, if it is thicker than 10 g / m 2 However, it is disadvantageous in terms of price. Not only this, but there are also cases where the rigidity becomes too strong and the packaging tape is cracked. <4> Intermediate layer In the present invention, the intermediate layer is a layer located between the substrate film and the heat-sealing layer, and includes a film made of a first intermediate layer and a second intermediate layer by a co-extrusion method. The first intermediate layer is a layer on the substrate film side. This layer imparts cushioning properties to the sealing tape, ensures the sealing strength with the carrier tape, and achieves a higher layer indirect strength through the adhesive layer and the substrate film. Furthermore, it is a layer that improves the film-forming stability during co-extrusion in order to take on the role of the lining to support the second intermediate layer. In the present invention, the first intermediate layer system includes a polyethylene resin. Here, examples of the polyethylene-based resin include linear (linear) low-density polyethylene using a unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic anhydride, and fumaric acid, and low-pressure polyethylene. Density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionic polymer resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymerization Materials, ethylene-propylene copolymers, and further polymer modified polyolefin resins such as methylpentene polymers, polyethylene, polyethylene resins, or polypropylene resins, or acid-modified polyolefin resins or the like A mixture of two or more. In order to ensure the sealing strength and fully exert the function of improving the stability of film formation, and to impart good flexibility and transparency to the sealing tape, it is particularly preferable to use a linear low-density polyethylene. In the present invention, the linear low-density polyethylene is a single-point catalyst such as a metallocene catalyst or a multi-point catalyst such as a Ziegler-Natta catalyst. Copolymer obtained by copolymerizing olefins at low temperature and low pressure. Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-dodecene, and the like. Examples of the copolymerization method include a method for polymerizing ethylene and an α-olefin by a low-pressure method, a slurry method, a solution method, and a gas phase method. The first intermediate layer may be one layer, or may include two or more layers having different characteristics. For example, in the case where a linear low-density polyethylene is used for the first intermediate layer, it is also possible to include a first linear-low-density polyethylene containing a relatively high density on the side close to the base material layer and excellent rewindability The intermediate layer A and the first intermediate layer B including a linear low-density polyethylene having a relatively low density and a side near the second intermediate layer are relatively soft. By using the first intermediate layer A to exhibit good rewindability, and by using the first intermediate layer B to exhibit cushioning properties, it is possible to achieve both reelability and cushioning properties. In order to exert appropriate cushioning properties, the density of the polyethylene resin layer used in the first intermediate layer and the second intermediate layer is preferably 0.900 g / cm 3 Above 0.940 g / cm 3 Hereinafter, the density of the polyethylene resin layer used in the first intermediate layer is more preferably 0.910 g / cm 3 Above 0.930 g / cm 3 the following. Especially, the density of the polyethylene resin layer used in the first intermediate layer B is preferably 0.910 g / cm 3 Above 0.915 g / cm 3 the following. If the density of the resin is higher than the above range, when heat-sealed to a carrier tape, cushioning properties as an intermediate layer are easily reduced, followability to the surface shape of the carrier tape is easily deteriorated, and adhesion strength (peel strength) with the carrier tape is easily deteriorated. It is easy to decrease, and the maximum difference in peel strength at the time of peeling tends to increase. If the resin density is lower than the above range, the fluidity of the molten resin that is heat-sealed on the carrier tape tends to become too strong, so the molten resin is easily extruded from the end of the sealing tape and contaminates the soldering iron of the heat-sealing fixture Or, when it is wound up and stored in the state of an intermediate laminated film, it tends to be attached, which tends to make handling difficult. The second intermediate layer is a layer on the heat-sealing layer side. This layer is a layer that exerts a stable layer indirectly with the heat-sealing layer and contributes to both sealing and easy peeling. In the present invention, the second intermediate layer system includes a resin composition including an ethylene · α-olefin copolymer and a styrene · butadiene block copolymer. Here, as the ethylene / α-olefin copolymer, a linear low-density polyethylene exemplified for the first intermediate layer can be used. By using the linear low-density polyethylene described above, transparency is improved, and control of the peel strength corresponding to the blending ratio of polystyrene and styrene-butadiene block copolymer becomes easy. Examples of the styrene-based monomer constituting the styrene-butadiene block copolymer include styrene, chlorostyrene, chloromethylstyrene, third butylstyrene, and vinyltoluene. Moreover, as a monomer copolymerizable with these, in addition to butadiene, isoprene, acrylonitrile, methacrylonitrile, etc. may be included. In addition to styrene and butadiene block copolymers, polystyrene, impact-resistant polystyrene, styrene and butadiene graft copolymers, and blocks or grafts of styrene and isoprene Branch copolymer, acrylonitrile · butadiene · styrene copolymer or a mixture of two or more of these. Particularly, a styrene-butadiene block copolymer obtained by copolymerizing 50 to 90% by mass of styrene and 50 to 10% by mass of butadiene can be suitably used. In a resin composition, when the ratio of the unit derived from a polystyrene resin and styrene is too much, transparency will fall, and on the other hand, the adhesiveness between layers will become high and easy peelability will fall. In addition, when co-extruded with the first intermediate layer, film forming properties tend to decrease. The resin composition forming the second intermediate layer can control the indirect adhesion strength to the layer of the heat-sealing layer by adjusting the blending ratio of the ethylene-α-olefin copolymer and the styrene-butadiene block copolymer, and take into account the needs Easy to peel and seal. Here, the blending ratio of the two can be appropriately adjusted by the supplier according to the content of the styrene-derived unit in the styrene-butadiene block copolymer used and the required sealing strength (peel strength). . In order to obtain the sealing strength and easy opening property suitable for the sealing tape from the balance with the first intermediate layer and the following heat sealing layer, the second intermediate layer preferably has 70 to 110 ° C, more preferably 82 ° C or higher, for example Vicat softening point at 82 to 85 ° C. In order to obtain such a second intermediate layer, the resin composition forming the second intermediate layer is, for example, a mixture of 30 to 70% by mass of an ethylene / α-olefin copolymer and 70 to 30% by mass of a styrene / butadiene block copolymer. Combined. The blending ratio of the two is more preferably 50 to 70% by mass with respect to the ethylene / α-olefin copolymer and 50 to 30% by mass with respect to the styrene / butadiene block copolymer, and still more preferably with respect to ethylene.・ The α-olefin copolymer is 55 to 70% by mass and the styrene-butadiene block copolymer is 45 to 30% by mass, and the total of the two is 100% by mass. If it exceeds the above range, the styrene content is small, and the Vicat softening point is too high, the softness of the layer is insufficient, which impairs the sealability and the adhesion between the layers. Conversely, if the styrene content is too large and the Vicat softening point is too low, the maximum difference in peel strength will increase and the easy peelability will be impaired. In the present invention, the Vicat softening point is a value measured based on the A120 method of JISK7206. The total thickness of the first and second intermediate layers is 15 to 50 μm, and more preferably 20 to 45 μm. If the thickness of the entire intermediate layer is too thin, sufficient cushioning properties cannot be exhibited and seal strength cannot be secured. In addition, the film formation becomes unstable and a uniform film cannot be formed. Conversely, if it is too thick, the sealing temperature must be increased and the sealing time must be extended to ensure the sealing strength, which is not good. The thickness of the second intermediate layer is 2 to 20 μm, and more preferably 5 to 15 μm. If the second intermediate layer is too thin, the sealing strength is reduced, which is not good. Conversely, if it is too thick, wrinkles or excessive thickness and pinholes are likely to occur during the film formation of the intermediate layer, which is unfavorable. The film forming the first and second intermediate layers is formed by coextruding the two layers by a conventional film-forming method such as an expansion method or a T-die method. Furthermore, the film formation by the co-extrusion method is different from the lamination method such as laminating only a monomer film, which extrudes a plurality of melted resins from a plurality of thin slit-shaped gaps. Go out. In order to improve the bonding strength with the adhesive layer and the heat-sealing layer, the surface of the film may be subjected to surface treatments such as corona discharge treatment, plasma treatment, and sandblasting treatment in advance as necessary. In addition, the first and second intermediate layers may include any additives as needed within a range that does not impair the effects of the invention. As such additives, various resin additives generally used for adjusting the moldability, productivity, and various physical properties of a resin film can be used. However, particles such as conductive fine particles are not included in the effects on transparency, interlayer adhesion, and easy peelability. <5> Heat-sealing layer In the present invention, the heat-sealing layer includes a transparent conductive heat-sealing material in which conductive fine particles are dispersed in an acrylic resin. In terms of easy peelability, heat sealability, and adhesion, the transparent conductive heat sealant preferably has a glass transition point of 20 to 100 ° C, and more preferably 30 to 60 ° C. If the glass transition point is too low, the heat-sealing layer will become soft and the coating film forming property and easy peelability will be impaired. Conversely, if the glass transition point is too high, the heat-sealing layer becomes hard and sufficient sealing strength cannot be obtained. In the present invention, the glass transition point is a value measured in accordance with JIS K7121. In the present invention, the acrylic resin includes homopolymers and copolymers of acrylic monomers. Examples of the acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate. Esters, etc. The (meth) acrylate means an acrylate or a methacrylate. Examples of the copolymerizable monomer include styrene-based monomers such as styrene, chlorostyrene, chloromethylstyrene, third butylstyrene, and vinyltoluene. Specific examples include poly (meth) acrylate, poly (meth) acrylate, poly (meth) acrylate, and (meth) acrylate-butyl (meth) acrylate copolymerization. Materials, random, block or graft copolymers of methyl (meth) acrylate and styrene, random, block or graft copolymers of ethyl (meth) acrylate and styrene, and the like. In terms of coating film formability, a copolymer with styrene can be particularly preferably used. The content of styrene in the copolymer of acrylate and styrene can be appropriately determined by the industry according to the resin forming the second intermediate layer and the required easy peelability. For example, the content of styrene is 0 to 30% by mass, more It is preferably 0 to 20% by mass. If the styrene content is too high, the glass transition point is lowered, which may impair coating film formation properties and easy peelability. Conversely, when the styrene content is small, it may be difficult to form a uniform coating film. By using these acrylic resins as adhesives for heat-sealing materials, the required heat-sealing properties or easy peelability can be achieved. Not only this, for example, even when a particularly good PET film is used as a base film, it may Prevent adhesions. In the present invention, the conductive fine particles dispersed in the acrylic resin are coated with barium sulfate particles doped with antimony-doped tin oxide or silicon dioxide particles or needle-shaped particles doped with antimony-doped tin oxide. . Antimony-doped tin oxide is obtained by replacing an oxygen atom on a tin oxide molecule with an antimony atom by an ion doping method. In the present invention, the antimony-doped tin oxide can be suitably used so that the volume resistivity becomes 500 Ω · m or less, preferably 100 Ω · m or less, to barium sulfate particles or silicon dioxide particles. The above-mentioned fine particles or acicular particles containing the antimony-doped tin oxide. By applying antimony-doped tin oxide to fine particles, a cheap and uniform fine powder can be obtained. In particular, when coating on barium sulfate particles with a refractive index of about 1.6 or silicon dioxide particles with a refractive index of about 1.5, the average particle diameter of particles that become cores is set to 0.3 μm. In the following, more preferably 0.2 μm or less, and further 0.1 μm or less, the particles do not diffuse visible light, so high transparency can be ensured. By using acicular tin oxide doped with antimony, higher conductivity can be obtained with less added amount, and higher transparency can be ensured. In the present invention, as the particle size of the acicular particles suitably used, the average length (average major diameter) is 100 to 2000 nm, and more preferably 200 to 2000 nm. The aspect ratio of the average length (average major diameter) / average diameter (average minor diameter) is 10 or more, and preferably 20 to 30. Furthermore, in the present invention, the average particle diameter of the microparticles obtained by coating antimony-doped tin oxide on barium sulfate particles or silicon dioxide particles is represented by a cumulative volume distribution by a laser diffraction scattering method. The measured 50% particle size (d50 median diameter), the average length and average diameter of the needle-like antimony-doped tin oxide and the average diameter were observed by using an electron microscope (SEM) and any arbitrary 30 The average value obtained by measurement. Barium sulfate particles doped with antimony-doped tin oxide or silicon dioxide particles or antimony-doped tin oxide needle-shaped particles are used as conductive fine particles and dispersed in an acrylic resin. A small amount of conductive fine particles achieve high antistatic properties. Therefore, the heat-sealing layer can be made thin and the transparency is not impaired. Furthermore, when heat-sealed with a carrier tape made of polystyrene or polycarbonate, it can complement the effects of the first and second intermediate layers to achieve good sealing strength and peel strength, so that both excellent sealing properties and Easy to peel off. The mass ratio of the acrylic resin to the conductive fine particles is 10 to 400 parts by mass based on 100 parts by mass of the acrylic resin. When the amount of the conductive fine particles is more than the above range, the transparency of the coating film is deteriorated, which is not good. On the other hand, if the amount of the conductive fine particles is less than the above range, the required antistatic performance cannot be obtained, which is not satisfactory. From the viewpoints of transparency, sealing properties, and antistatic effect, the thickness of the heat-sealing layer is preferably in the range of 0.1 to 5 μm, particularly 0.2 to 2 μm. In the present invention, the heat-sealing layer includes a combination of the above-mentioned acrylic resin and antimony-doped tin oxide barium sulfate particles or silicon dioxide particles or needle-like antimony-doped tin oxide. Making the layer thinner can also obtain a sufficient antistatic effect. In the present invention, the surface resistivity of the heat-sealing layer is 10 at 22 ° C and 40% RH. 5 ~ 10 12 Ω / □. In addition, at 23 ± 5 ° C and 12 ± 3% RH, the charge decay time required to attenuate 99% from 5000 V is less than 1 second, and has excellent electrostatic characteristics. If the above surface resistivity exceeds 10 12 Ω / □, the electrostatic diffusion effect becomes extremely poor, and it is difficult to protect electronic parts from electrostatic damage. 5 Ω / □, the electronic parts may be energized from the outside through the cover material, and the electronic parts may be damaged by electricity. On the other hand, when the charge decay time, which is the standard for the diffusion rate of the charges generated by static electricity, exceeds 1 second, the electrostatic diffusion effect becomes extremely poor, and it is difficult to protect the electronic parts from electrostatic damage. In addition, the surface resistivity and charge decay time can be measured according to MIL-B-81705C, which is a military standard in the United States. If necessary, the heat sealing layer may contain additives such as a dispersion stabilizer, a surfactant, and an anti-blocking agent. The heat seal layer can be applied by a gravure coating method, an air knife coating method, a blade coating method, a knife coating method, a rod coating method, a direct roll coating method, or a reverse roll coating. A coating method such as a cloth method, a swash plate coating method, or a slot coating method is applied and formed on the second intermediate layer. <6> The conductive sealing tape has the transparency such that the sealing tape of the present invention has a total light transmittance of 70% or more and a haze value of 30% or less. More preferably, the total light transmittance is 75% or more and the haze value is 25% or less, and even more preferably the total light transmittance is 80% or more and the haze value is 23% or less. Therefore, the tape package using the sealing tape of the present invention can be inspected and confirmed by the visual inspection or the camera inspection or the filling state from the sealing tape in an unopened state. In addition, when the self-supporting tape is unsealed, the sealing tape of the present invention has peeling (interlayer peeling) between the second intermediate layer and the heat-sealing layer at the sealing portion without being subjected to the thermal fusion condition of the heat-sealing layer and the carrier tape. Effect of stable peeling performance. The peel strength (layer indirect adhesion strength) is weaker than the peel strength of the heat-sealing layer and the carrier tape, and is preferably in the range of 100 to 1200 gf / 15 mm. If the peel strength does not reach 100 gf / 15 mm, there is a danger that peeling may occur during transportation and storage of the package and the contents may fall off. In addition, if the peel strength exceeds 1200 gf / 15 mm, the carrier tape may vibrate and cause the contents to fly out when the sealing tape is peeled off, which is not preferable. In the present invention, the peel strength is a value of 180-degree peel (peeling speed: 300 mm / min) under an environment of 23 ° C. and a relative humidity of 40%. The maximum difference in peel strength is preferably 30 gf / 1 mm or less. If the maximum difference in peel strength exceeds 50 gf / 1 mm, the carrier tape may vibrate and cause the contents to fly out when the sealing tape is peeled off, which is not satisfactory. In addition, the maximum difference in peel strength referred to here means the maximum and minimum peel strength when the sealing tape and the carrier tape are heat-sealed by using two heat sealing strips with a width of 0.5 mm. The difference in values. The measurement conditions for the maximum difference in peel strength are the values when a measurement length of 20 mm was peeled at 180 degrees at a peeling speed of 300 mm / min under an environment of 23 ° C and a relative humidity of 40%. The material of the carrier tape to which the sealing tape of the present invention is applied is polyvinyl chloride, polystyrene, polyester, polypropylene, polycarbonate, polyacrylonitrile, ABS (Acrylonitrile Butadiene Styrene, acrylonitrile-butadiene-benzene Ethylene copolymers) and the like, particularly preferably polystyrene and polycarbonate. In addition, conductive carbon black fine particles, metal fine particles, conductive fine particles that make a metal oxide conductive, an organic silicon compound, or a surfactant may be mixed in these resins as an antistatic measure or coated with such materials. Material. Next, the present invention will be specifically described with examples corresponding to the types of the conductive fine particles. [Example] <Experiment I> [Example 1] The first intermediate layer (thickness 20) containing linear low-density polyethylene (EVOLUE SP2520 manufactured by Prime Polymer) was formed by coextrusion. μm) and 60% by mass of linear low-density polyethylene (ULT-ZEX 2021L manufactured by Prime Polymer) with a density of 0.919 and a styrene-butadiene block copolymer (Asahi Kasei Chemicals) The second intermediate layer (thickness 10 μm) of the resin composition (Vica softening point 85 ° C.) of Asaflex 810 manufactured by Asaflex 810, 65% by mass of styrene content, and 40% by weight, to obtain a film having a total thickness of 30 μm. The surface of the first intermediate layer of the film and the biaxially stretched PET film with a thickness of 12 μm (E7415 single-sided antistatic and single-sided corona made by Toyobo Co., Ltd.) with an adhesive layer containing a polyol and a hardener. Treatment type) Corona treated surface is dry laminated. Next, 240 parts by mass of conductive fine particles (barium sulfate particles doped with antimony doped with tin oxide with an average particle diameter of 0.25 μm) were dispersed in an acrylic resin (methacrylic acid methyl) by a roll coating method. A transparent conductive heat-sealing material (glass transition point: 50 ° C) made of 100 parts by mass of a copolymer such as an ester) was applied to the surface of the second intermediate layer of the obtained laminated body at a thickness of 2 μm to produce the present invention. Of packaging tape. With respect to the obtained sealing tape, the surface resistivity, charge decay time, haze value, total light transmittance, peel strength, and maximum difference in peel strength were measured under the following conditions. (Surface resistivity) The measurement was performed at 22 ° C and 40% RH using Hiresta UP manufactured by Mitsubishi Chemical Analytech Co., Ltd. with a probe URS and an applied voltage of 10 V. (Charge decay time) At 23 ± 5 ° C and 12 ± 3% RH, according to MIL-B-81705C, and using STATIC DECAY METER-406C manufactured by ETS company (Electro-Tech Systems, Inc) to measure 99 decay from 5000 V % Time required. (Haze value and total light transmittance) Measurement was performed in accordance with JIS K7136 and JIS K7361 using Haze-gard II manufactured by Toyo Seiki Seisakusho Co., Ltd. (Peel strength) at 150 ° C, 0.5 seconds, 3.0 kgf / cm 2 The obtained sealing tape was heat-sealed on a polystyrene substrate under the conditions, and then the peeling strength was measured at 23 ° C and 40% RH using a Tensilon universal testing machine HTH-100 manufactured by Toyo Baldwin Co., Ltd. (Peeling speed = 300 mm / min, 180 ° peeling) (Maximum difference in peeling strength) The obtained sealing tape was heat-sealed under the conditions of 150 ° C, 0.4 seconds, and 3.0 kgf using two 0.5 mm wide heat sealing strips The peel strength was measured on a polystyrene carrier tape using a peel strength tester VG-20 manufactured by Vanguard Systems at 23 ° C and 40% RH (peel speed = 300 mm / min, and a length of 20 mm was measured. , 180 ° peeling), and the difference between the maximum value and the minimum value was determined. The measurement results are shown in Table 1 below. [Table 1] The packaging tape of the present invention manufactured in the embodiment has a suitable surface resistivity and a sufficiently short charge decay time, so it has excellent electrostatic characteristics and can well protect electronic parts from electrostatic damage. In addition, it has high transparency, and the state of the contents can be easily confirmed even by a camera inspection. Furthermore, it has a good peeling strength, and while the contents are sufficiently sealed, the easy-opening property is maintained. In particular, the maximum difference in peel strength between the peel strengths is small, and an extremely smooth peeling feeling can be obtained. [Example 2] A sealing tape of the present invention was produced in the same manner as in Example 1 except that silicon dioxide particles were used as the core material of the conductive fine particles instead of barium sulfate particles. The obtained sealing tape showed the same properties as the sealing tape of Example 1. [Example 3] A resin composition containing 80% by mass of the linear low-density polyethylene and 20% by weight of the styrene-butadiene block copolymer was used as a second intermediate layer. Example 1 produced the packaging tape of the present invention in the same manner. The obtained sealing tape showed suitable surface resistivity and electrostatic characteristics. Although the peeling strength was suitable, it was smaller than that in Example 1 and the sealing property was slightly inferior. [Comparative Example 1] A heat sealing material obtained by dispersing 240 parts by mass of the tin oxide powder in 100 parts by mass of the acrylic resin was used as the conductive fine particles except for antimony-free tin oxide powder. Example 1 produced the packaging tape in the same manner. Compared with the sealing tape of the embodiment, the obtained sealing tape has a larger surface resistivity, a longer charge decay time, and a lower electrostatic diffusion effect. [Comparative Example 2] A packaging tape was produced in the same manner as in Example 1 except that a polyethylene film having a thickness of 30 μm was used instead of the coextruded film including the first and second intermediate layers. Compared with the obtained sealing tape of the embodiment, the obtained sealing tape has a lower indirect contact strength between the heat-sealing layer and the intermediate layer, and a lower sealing performance. <Experiment IIA> [Example 1] A first intermediate layer (thickness: 20 μm) including a linear low-density polyethylene (EVOLUE SP2520 manufactured by Prime Polymer) was formed by coextrusion, and Includes linear low-density polyethylene (ULT-ZEX 2021L manufactured by Prime Polymer) with a density of 0.919 and 60% by mass of styrene-butadiene block copolymer (Asaflex 810 manufactured by Asahi Kasei Chemicals) The second intermediate layer (thickness: 10 μm) of the resin composition (vicat softening point: 85 ° C.) of 40% by weight of a styrene content rate of 65% by mass, yielded a film having a total thickness of 30 μm. The surface of the first intermediate layer of the film and the biaxially stretched PET film with a thickness of 12 μm (E7415 single-sided antistatic and single-sided corona made by Toyobo Co., Ltd.) with an adhesive layer containing a polyol and a hardener. Treatment type) Corona treated surface is dry laminated. Next, 210% by mass of conductive fine particles (acicular particles doped with antimony tin oxide, FS-10P manufactured by Ishihara Sangyo Co., Ltd.) were dispersed in styrene-methacrylate by a roll coating method. A transparent conductive heat-sealing material (glass transition point: 50 ° C.) made of 100% by mass of the copolymer was applied to the surface of the second intermediate layer of the obtained laminated body at a thickness of 2 μm to manufacture the sealing tape of the present invention. With respect to the obtained sealing tape, the surface resistivity, charge decay time, haze value, total light transmittance, peel strength, and maximum difference in peel strength were measured under the following conditions. The measurement results are shown in Table 2 below. [Table 2] [Example 2] A resin composition containing 80% by mass of the linear low-density polyethylene and 20% by weight of the styrene-butadiene block copolymer was used as a second intermediate layer. Example 1 produced the packaging tape of the present invention in the same manner. The obtained sealing tape showed suitable surface resistivity and electrostatic characteristics. Although the peeling strength was suitable, it was smaller than that in Example 1 and the sealing property was slightly inferior. [Example 3] ULT-ZEX UZ2022L made of Prime Low Polyethylene (Prime Polymer) was used, and the density was 0.919 g / cm 3 ) A sealing tape of the present invention was produced in the same manner as in Example 1 except that 55% by mass of the resin composition containing 45% by weight of the styrene-butadiene block copolymer was used as the second intermediate layer. The obtained sealing tape exhibited performance equivalent to that of Example 1. [Example 4] ULT-ZEX UZ2022L made from Prime Polymer (strand) was used, and the density was 0.919 g / cm 3 ) The sealing tape of the present invention was produced in the same manner as in Example 1 except that 80% by mass of the resin composition containing 20% by weight of the styrene-butadiene block copolymer was used as the second intermediate layer. The obtained sealing tape showed the same surface resistivity and electrostatic characteristics as in Example 1. Although the peeling strength was appropriate, it was slightly smaller than that in Example 1, and the sealing property was slightly inferior. [Example 5] A linear low-density polyethylene (EVOLUE SP2020 manufactured by Prime Polymer) was used, and the density was 0.916 g / cm 3 ) A sealing tape of the present invention was produced in the same manner as in Example 1 except that a resin composition of 60% by mass and 40% by weight of the styrene-butadiene block copolymer was used as the second intermediate layer. The obtained sealing tape exhibited performance equivalent to that of Example 1. [Comparative Example 1] An antimony-free tin oxide powder was used as the conductive fine particles, and 210% by mass of the conductive fine particles were dispersed in 100% by mass of the styrene-methacrylate copolymer. Other than that, a packaging tape was produced in the same manner as in Example 1. Compared with the sealing tape of the embodiment, the obtained sealing tape has a larger surface resistivity, a longer charge decay time, and a lower electrostatic diffusion effect. [Comparative Example 2] A packaging tape was produced in the same manner as in Example 1 except that a polyethylene film having a thickness of 30 μm was used instead of the coextruded film including the first and second intermediate layers. Compared with the sealing tape of the embodiment, the obtained sealing tape has a lower indirect contact strength between the heat-sealing layer and the intermediate layer, and a lower sealing performance. 〈Experiment IIB〉 [Example 1] Film formed by coextrusion including linear low-density polyethylene 1 (EVOLUE SP2020 manufactured by Prime Polymer Co., Ltd., density 0.916 g / cm 3 ) Of the first intermediate layer A (thickness 7.5 μm), including linear low-density polyethylene 3 (EVOLUE SP1520 manufactured by Prime Polymer), density 0.913 g / cm 3 ) 'S first intermediate layer B (thickness 12.5 μm) and resin composition 2B1 (containing 55 mass% of linear low density polyethylene 1, 45 weight% of styrene-butadiene block copolymer 1 ( A second intermediate layer (thickness 10 μm) of a mixture of Asaflex 810 manufactured by Asahi Kasei Chemicals (stock), 65% by mass of styrene), Vicat softening point 85 ° C.), to obtain a film having a total thickness of 30 μm. A 12-m-thick biaxially stretched PET film 1 (manufactured by Toyobo Co., Ltd.) with a two-liquid curable urethane adhesive layer containing a polyhydric alcohol and a hardener and a surface of the first intermediate layer of the film The corona-treated surface of E7415 single-sided antistatic and single-sided corona treatment type) is dry laminated. Next, the transparent conductive heat-sealing material 2B1 (contains 68% by mass of conductive fine particles 1 (FS-10P manufactured by Ishihara Sangyo Co., Ltd.) and needle-shaped particles doped with antimony tin oxide were prepared by a roll coating method ), A mixture of 32% by mass of a styrene-methacrylate copolymer, with a glass transition point of 50 ° C.) was coated on the surface of the second intermediate layer of the obtained laminated body with a thickness of 1 μm as a sealing layer to manufacture the present invention. Invented packaging tape. With respect to the obtained sealing tape, the surface resistivity, charge decay time, haze value, total light transmittance, peel strength, and maximum difference in peel strength were measured under the following conditions. The obtained sealing tape showed suitable surface resistivity, electrostatic characteristics, and peeling strength. [Example 2] A resin composition 2B2 (a mixture containing 60% by mass of linear low-density polyethylene 3 and 40% by mass of styrene-butadiene block copolymer 1 and a Vicat softening point of 85 ° C) was used. Except as a second intermediate layer, the packaging tape of the present invention was manufactured in the same manner as in Example 1. The obtained sealing tape showed suitable surface resistivity, electrostatic characteristics, and peeling strength. [Comparative Example 1] Linear low-density polyethylene 2 (EVOLUE SP2520 manufactured by Prime Polymer Co., Ltd., density 0.925 g / cm 3 ) As the first intermediate layer A, without the first intermediate layer B, a resin composition 2B3 (containing 55% by mass of linear low-density polyethylene 4 (ULT-ZEX UZ2022L manufactured by Prime Polymer) was used, and the density was 0.919 g / cm 3 ), 45% by weight of a mixture of styrene-butadiene block copolymer 1) as the second intermediate layer, using a transparent conductive heat-seal 2B2 (contains 68% by mass of conductive fine particles 2 (antimony-free tin oxide) Needle-shaped particles) and a mixture of 32% by mass of styrene-methacrylate copolymer 1) were used as a sealing layer, and the sealing tape of the present invention was produced in the same manner as in Example 1. The obtained packaging tape showed results of very high surface resistivity, very long charge decay time, and poor electrical characteristics. [Comparative Example 2] A linear low-density polyethylene 2 was used as the first intermediate layer A, a first intermediate layer B was not used, and a linear low-density polyethylene 4 was used as the second intermediate layer. Example 1 produced the packaging tape of the present invention in the same manner. The obtained sealing tape showed results of very low peel strength, failure to measure the maximum difference in peel strength, and poor adhesion. [table 3]