JP4295820B2 - Adhesive composition and its adhesive sheet - Google Patents

Description

（式中、Ｒは炭素数２〜２０の脂肪族の炭化水素基である）
で表される繰り返し単位を有するジオ―ルであり、たとえば、ブタンジオ―ルなどのジオ―ル成分とエチレンカ―ボネ―トなどのカ―ボネ―ト化合物との反応により、得られるものである。市販品として、ダイセル化学工業（株）製の商品名「ＰＬＡＣＣＥＬ ＣＤ２２０ＰＬ」、「同ＣＤ２１０ＰＬ」「同ＣＤ２０５ＰＬ」、「同ＣＤ２２０」「同ＣＤ２１０」などがある。
【００１１】
ポリオ―ル成分としては、上記の脂肪族系ポリカ―ボネ―トジオ―ルのほか、エチレングリコ―ル、プロピレングリコ―ル、ブタンジオ―ル、ヘキサンジオ―ル、オクタンジオ―ル、デカンジオ―ル、オクタデカンジオ―ルなどの直鎖状のジオ―ル成分なども使用できる。このようなポリオ―ル成分と反応させる多塩基酸成分は、炭素数が２〜２０の脂肪族または脂環族の炭化水素基を分子骨格としたものであり、上記炭化水素基は直鎖状であつても分枝状であつてもよい。具体的には、マロン酸、コハク酸、メチルコハク酸、アジピン酸、セバシン酸、１，１２−ドデカン二酸、１，１４−テトラデカン二酸、ｎ−ヘキシルアジピン酸、テトラヒドロフタル酸、エンドメチレンテトラヒドロフタル酸などや、これらの酸無水物やエステルなどの誘導体が用いられる。
【００１２】
本発明におけるＢ成分のアクリル系重合体は、上記Ａ成分のポリエステル系重合体に基づくすぐれた粘着特性と剥離ライナの剥離性を損なうことなく、その初期粘着性を改善するためのものであり、炭素数が４〜１４のアルキル基を有する（メタ）アクリル酸アルキルエステルを主単量体とした重合体であつて、かつ酸成分を実質的に含有しない、ガラス転移温度が−１０℃以下、好ましくは−１５℃以下（通常−９０℃程度まで）の重合体が用いられる。ここで、酸成分を実質的に含有しないとは、単量体成分としてアクリル酸、メタクリル酸、イタコン酸、マレイン酸などの不飽和カルボン酸を使用しないことを意味し、これにより電子機器などの腐食を防ぐようにしたものである。また、ガラス転移温度を−１０℃以下とすることにより、粘着力などの粘着特性とともに、上記本来の目的である初期粘着性の改善に好ましい結果を得るものである。
【００１３】
主単量体としての炭素数が４〜１４のアルキル基を有する（メタ）アクリル酸アルキルエステルは、ブチル基、イソブチル基、イソアミル基、ヘキシル基、ヘプチル基、２−エチルヘキシル基、イソオクチル基、イソノニル基、ラウリル基、イソミリスチル基などのアルキル基を有する（メタ）アクリル酸のアルキルエステルである。この主単量体とともに、不飽和カルボン酸以外の単量体として、たとえば酢酸ビニル、スチレン、２−ヒドロキシエチル（メタ）アクリレ―ト、（メタ）アクリロニトリルなど、アクリル系粘着剤に一般に用いられている公知のビニル系単量体を併用することもできる。これら他の単量体は、上記主単量体が５０重量％以上となる範囲内で使用するのが望ましい。
【００１４】
本発明の粘着剤組成物は、通常は、▲１▼上記Ａ成分のポリエステル系重合体と上記Ｂ成分のアクリル系重合体を別々に合成したのち、両者を塊状または溶液状で混合することにより、調製することができる。しかし、場合によつては、▲２▼一方の重合体中で他方を重合させるといつた方法で調製してもよいし、また、▲３▼両者を同時に重合するといつた方法で調製してもよい。
【００１５】
これらの調製方法において、Ａ成分のポリエステル系重合体とＢ成分のアクリル系重合体とは、両者の合計量中、Ａ成分のポリエステル系重合体が５０〜９５重量％、好ましくは６０〜９０重量％であり、Ｂ成分のアクリル系重合体が５０〜５重量％、好ましくは４０〜１０重量％であるのがよい。Ａ成分のポリエステル系重合体が９５重量％を超える、つまりＢ成分のアクリル系重合体が５重量％未満となると、初期粘着性の改善効果が十分に得られず、またＡ成分のポリエステル系重合体が５０重量％未満となる、つまりＢ成分のアクリル系重合体が５０重量％を超えると、粘着特性や剥離ライナの剥離性が低下する。
【００１６】
本発明の粘着剤組成物は、上記Ａ成分のポリエステル系重合体と上記Ｂ成分のアクリル系重合体とを主成分としたものであるが、通常はこれを架橋処理して、粘着特性にすぐれたものとすることができる。架橋処理は、架橋剤として、ポリイソシアネ―ト化合物、エポキシ化合物、アジリジン化合物などを加えて、これと上記の両重合体に含まれる水酸基などの官能基と反応させればよい。また、本発明の粘着剤組成物には、上記の架橋剤のほか、必要により、粘着付与剤、無機または有機の充填剤、金属粉、顔料などの粉体、粒子状物、箔状物などの従来公知の各種の添加剤を、含ませることができる。
【００１７】
本発明の粘着シ―ト類は、ポリエステルフイルムなどの各種のプラスチツクフイルム、紙、不織布、発泡体、金属箔、これらの積層物などを支持体として、この支持体の片面または両面に上記の粘着剤組成物からなる層を片面で通常１０〜１５０μｍの厚さに設けて、シ―ト状やテ―プ状などの形態としたものであり、その粘着面、つまり上記粘着剤組成物からなる層の表面には、表面保護や取り扱い性の点より、剥離ライナが貼り合わされる。
【００１８】
剥離ライナには、シリコ―ン処理していない剥離ライナを使用でき、とくに、ポリオレフイン系フイルムが好ましく用いられる。ポリオレフイン系フイルムには、ポリエチレン、ポリプロピレン、ポリメチルペンテン、エチレン−プロピレン共重合体またはこれらの混合物からなるフイルム、表面が上記同様のポリオレフインで加工されたフイルムなどを使用することができる。
【００１９】
このように作製される本発明の粘着シ―ト類は、すぐれた粘着特性を発揮し、初期粘着性にもすぐれているため、通常の粘着用途はもちろんのこと、瞬間的な接着が必要な用途、たとえば高速連続接着作業や接着後ただちに応力がかかるような用途にも、十分に使用できる。また、ポリエステル系重合体とともに使用するアクリル系重合体が酸性基を実質的に含まないため、酸性基による悪影響がなく、さらに、粘着面に貼り合わせる剥離ライナがシリコ―ン処理を施していない剥離ライナであつても、良好な剥離性が得られるため、粘着面へのシリコ―ンの移行の心配もなく、したがつて、酸成分やシリコ―ンの存在を好まない電子機器用途などにも、問題なく使用することができる。
【００２０】
【実施例】
つぎに、本発明を実施例によりさらに詳細に説明するが、本発明の範囲は以下の実施例によりなんら制限を受けるものではない。なお、以下において、部とあるのは重量部を意味するものとする。
【００２１】
実施例１
撹拌機、温度計および水分離管を付した四つ口セパラブルフラスコに、液状のポリカ―ボネ―トジオ―ル〔ダイセル化学工業（株）製の商品名「ＰＬＡＣＣＥＬ ＣＤ２２０ＰＬ」、水酸基価：５６．１ＫＯＨmg／ｇ〕２５０部、セバシン酸２６．６部、触媒としてチタニウムテトライソプロポキシド（以下、ＴＰＴという）０．１部を投入し、反応水排出溶剤としての少量のトルエンとキシレンの存在下、撹拌を開始しながら１８０℃まで昇温し、この温度で保持した。しばらくすると水の流出分離が認められ、反応が進行し始めた。約２５時間反応を続けて、重量平均分子量が３．８万のポリエステル系重合体の溶液を得た。
【００２２】
これとは別に、冷却管、窒素導入管、温度計および撹拌装置を備えた反応容器に、トルエン１００部を溶媒として、アクリル酸イソノニル５０部、アクリル酸エチル３８部、メタクリル酸メチル１０部、アクリル酸２−ヒドロキシエチル２部、過酸化ベンゾイル０．２部を投入し、窒素気流中で重合させることにより、ガラス転移温度が−４１℃で、重量平均分子量が４５万のアクリル系重合体の溶液を得た。
【００２３】
つぎに、上記のポリエステル系重合体の溶液とアクリル系重合体の溶液とを、ポリエステル系重合体９０部あたりアクリル系重合体１０部となるように、混合し、これにさらに架橋剤としてトリメチロ―ルプロパンのトリレンジイソシアネ―ト付加物（日本ポリウレタン社製の商品名「コロネ―トＬ」）３部（固形分）を加えて、混合し、粘着剤組成物の溶液とした。この粘着剤組成物の溶液を、アプリケ―タにより、厚さが３８μｍのポリエチレンテレフタレ―トフイルム上に塗布し、１２０℃で３分間乾燥して、厚さが３０μｍの粘着剤組成物の層を形成した。その粘着面に、剥離ライナとして厚さが１５０μｍのポリエチレンフイルムを貼り合わせて、粘着テ―プを作製した。
【００２４】
実施例２
実施例１で得たポリエステル系重合体の溶液とアクリル系重合体の溶液とを、ポリエステル系重合体８０部あたりアクリル系重合体２０部となるように、混合し、これにさらにトリメチロ―ルプロパンのトリレンジイソシアネ―ト付加物（日本ポリウレタン社製の商品名「コロネ―トＬ」）３部（固形分）を加えて、混合し、粘着剤組成物の溶液とした。この粘着剤組成物の溶液を用いて、以下、実施例１と同様にして、粘着テ―プを作製した。
【００２５】
実施例３
撹拌機、温度計および水分離管を付した四つ口セパラブルフラスコに、液状のポリカ―ボネ―トジオ―ル〔ダイセル化学工業（株）製の商品名「ＰＬＡＣＣＥＬ ＣＤ２２０ＰＬ」、水酸基価：５６．１ＫＯＨmg／ｇ〕２５０部、アゼライン酸２４．６部、触媒としてのＴＰＴを０．１部投入し、反応水排出溶剤としての少量のトルエンとキシレンの存在下、撹拌を開始しながら１８０℃まで昇温し、この温度で保持した。しばらくすると水の流出分離が認められ、反応が進行し始めた。約２７時間反応を続けて、重量平均分子量が４．１万のポリエステル系重合体の溶液を得た。
【００２６】
これとは別に、冷却管、窒素導入管、温度計および撹拌装置を備えた反応容器に、トルエン１００部を溶媒として、アクリル酸ｎ−ブチル７０部、アクリル酸エチル２７部、アクリル酸２−ヒドロキシエチル３部、過酸化ベンゾイル０．２部を投入し、窒素気流中で重合させることにより、ガラス転移温度が−４６℃で、重量平均分子量が３８万のアクリル系重合体の溶液を得た。
【００２７】
つぎに、上記のポリエステル系重合体の溶液とアクリル系重合体の溶液とを、ポリエステル系重合体７０部あたりアクリル系重合体３０部となるように、混合し、これにさらに架橋剤としてトリメチロ―ルプロパンのトリレンジイソシアネ―ト付加物（日本ポリウレタン社製の商品名「コロネ―トＬ」）３部（固形分）を加えて、混合し、粘着剤組成物の溶液とした。この粘着剤組成物の溶液を用いて、以下、実施例１と同様にして、粘着テ―プを作製した。
【００２８】
比較例１
実施例１で得たポリエステル系重合体の溶液とアクリル系重合体の溶液とを、ポリエステル系重合体４０部あたりアクリル系重合体６０部となるように、混合し、これにさらにトリメチロ―ルプロパンのトリレンジイソシアネ―ト付加物（日本ポリウレタン社製の商品名「コロネ―トＬ」）３部（固形分）を加えて、混合し、粘着剤組成物の溶液とした。この粘着剤組成物の溶液を用いて、以下、実施例１と同様にして、粘着テ―プを作製した。
【００２９】
比較例２
実施例１で得たポリエステル系重合体の溶液に、ポリエステル系重合体１００部（固形分）あたり、架橋剤としてトリメチロ―ルプロパンのヘキサメチレンジイソシアネ―ト付加物（日本ポリウレタン社製の商品名「コロネ―トＬ」）３部（固形分）を加えて、混合し、粘着剤組成物の溶液とした。この粘着剤組成物の溶液を用いて、以下、実施例１と同様にして、粘着テ―プを作製した。
【００３０】
比較例３
実施例１で得たアクリル系重合体の溶液に、アクリル系重合体１００部（固形分）あたり、架橋剤としてトリメチロ―ルプロパンのヘキサメチレンジイソシアネ―ト付加物（日本ポリウレタン社製の商品名「コロネ―トＬ」）２部（固形分）を加えて、混合し、粘着剤組成物の溶液とした。この粘着剤組成物の溶液を用いて、以下、実施例１と同様にして、粘着テ―プを作製した。
【００３１】
上記の実施例１〜３および比較例１〜３の各粘着テ―プについて、以下の方法により、初期粘着力、粘着力および剥離ライナの剥離力を測定した。これらの測定結果は、表１に示されるとおりであつた。
【００３２】
＜初期粘着力＞
粘着テ―プを２０mm×１００mmの大きさに切断し、２３℃，６５％ＲＨの雰囲気中で、剥離ライナを引き剥がして、被着体としてのアルミ板に、２Kgロ―ラ１往復の条件で圧着した。１０秒後に、剥離速度３００mm／分の条件で、１８０°剥離粘着力（Kg／２０mm幅）を測定し、初期粘着力とした。
【００３３】
＜粘着力＞
アルミ板への圧着後、３０分経過後に測定した以外は、初期粘着力の場合と同様にして、１８０°剥離粘着力（Kg／２０mm幅）を測定し、粘着力とした。
【００３４】
＜剥離ライナの剥離力＞
粘着テ―プを５０mm×１００mmの大きさに切断し、支持体であるポリエチレンテレフタレ―トフイルム側を両面テ―プによりステンレス板に固定したのち、２３℃，６５％ＲＨの雰囲気中で、粘着テ―プから剥離ライナを引張り速度３００mm／分の条件で剥離したときの剥離力（ｇ／５０mm幅）を測定した。
【００３５】

【００３６】
上記の表１の結果から明らかなように、本発明の実施例１〜３の各粘着テ―プは、粘着力および剥離ライナの剥離性にすぐれ、また初期粘着性にもすぐれていることがわかる。これに対して、アクリル系重合体の使用量が多すぎる比較例１の粘着テ―プは、アクリル系重合体を単独で用いた比較例３の粘着テ―プの場合と同様に、粘着特性と剥離ライナの剥離性に劣り、ポリエスル系重合体を単独で用いた比較例２の粘着テ―プは、初期粘着性に劣つている。
【００３７】
【発明の効果】
以上のように、本発明は、脂肪族系ポリカ―ボネ―トジオ―ルを必須のポリオ―ル成分としたポリエステル系重合体とともに、酸成分を実質的に含有しないガラス転移温度が−１０℃以下のアクリル系重合体を特定量使用したことにより、粘着力とさらに初期粘着力にすぐれ、しかもポリオレフイン系フイルムなどのシリコ―ン処理を施していない剥離ライナを用いても、良好な剥離性が得られる、したがつて、電子機器用途などに対して、酸成分やシロキサンガスの発生による機器の腐食や誤動作などの問題が起こらない、また瞬間的な接着が必要な用途、たとえば高速連続接着作業や接着後ただちに応力がかかるような用途にも十分に使用できる粘着剤組成物とその粘着シ―ト類を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure-sensitive adhesive composition containing a polyester polymer and an acrylic polymer, and a pressure-sensitive adhesive sheet in the form of a sheet or tape.
[0002]
[Prior art]
The acrylic pressure-sensitive adhesive is mainly composed of an acrylic copolymer obtained by copolymerizing (meth) acrylic acid alkyl ester as a main monomer and adding an acid component such as acrylic acid to this. It is widely used in various fields as having excellent adhesive properties such as high adhesive strength. However, since the acrylic pressure-sensitive adhesive contains the acid component, when it is used as an adhesive material for an electronic device or the like, if the device is directly touched, the device or the like may be corroded.
[0003]
Adhesive sheets have a release liner attached to protect the adhesive surface and handleability. Acrylic adhesives have a surface that is treated with a silicone treatment to obtain good release properties. You are using a liner. However, with this type of release liner, silicon migrates to the adhesive surface and siloxane gas is generated inside the electronic equipment, which can cause corrosion and malfunction of the electronic equipment.
[0004]
On the other hand, recently, an adhesive mainly composed of a polyether polymer having a carbonate bond in the molecule has been proposed. Such polyester-based adhesives do not have to worry about corrosion of electronic equipment due to acid components such as acrylic adhesives, and have been subjected to silicone treatment such as polyolefin film to protect the adhesive surface. Even when a release liner is used, sufficiently good peelability can be obtained, so there is no concern about the transfer of silicone to the adhesive surface. There is no particular risk of malfunction.
[0005]
[Problems to be solved by the invention]
As described above, the polyester-based pressure-sensitive adhesive has an advantage that there is no possibility of causing corrosion or malfunction of an electronic device due to generation of an acid component or a siloxane gas, compared with an acrylic pressure-sensitive adhesive. There is a drawback that it is poor in tackiness. Therefore, it cannot be used for applications that require instantaneous bonding, for example, high-speed continuous bonding work or applications where stress is applied immediately after bonding.
[0006]
In light of such circumstances, the present invention avoids corrosion and malfunction of electronic devices due to generation of acid components and siloxane gas, and provides a pressure-sensitive adhesive composition with improved initial tackiness and its pressure-sensitive adhesive sheets. It is intended to provide.
[0007]
[Means for Solving the Problems]
As a result of intensive investigations to achieve the above object, the present inventors have found that by using a specific acrylic polymer in combination with a polyether polymer having a carbonate bond in the molecule, In addition to avoiding problems such as corrosion and malfunction of electronic equipment due to the generation of components and siloxane gas, it is possible to obtain adhesive compositions and adhesive sheets that exhibit good adhesive properties, especially improved initial adhesiveness. The present invention has been completed.
[0008]
That is, the present invention relates to A) 60 to 90 % by weight of a polyester polymer having an aliphatic polycarbonate diol as an essential polyol component, and B) a glass transition temperature substantially not containing an acid component is −10 ° C. or lower. A pressure-sensitive adhesive composition comprising 40 to 10% by weight of an acrylic polymer (Claim 1), in particular, a pressure-sensitive adhesive having the above-mentioned constitution wherein the weight average molecular weight of the polyester polymer of the component A is 10,000 or more The present invention relates to an agent composition (claim 2). Further, the present invention relates to a sheet-like or tape-like pressure-sensitive adhesive sheet (Claim 3) having a layer made of the pressure-sensitive adhesive composition having the above-described structure on one side or both sides of a support. .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the polyester-based polymer of component A is a polyester having an aliphatic polycarbonate diol as an essential polyol component, that is, 50% by weight or more of the aliphatic polycarbonate diol. The polyester of a polyol component and a polybasic acid component, preferably 60% by weight or more, having a weight average molecular weight of 10,000 or more and usually 200,000, preferably 20,000 to 150,000, more preferably 3 What is 10,000 to 120,000 is used. If the molecular weight of the polyester polymer is too low, it is difficult to obtain good results in adhesive properties such as adhesive strength.
[0010]
Aliphatic polycarbonate diol is the following formula:

(In the formula, R is an aliphatic hydrocarbon group having 2 to 20 carbon atoms)
A diol having a repeating unit represented by, for example, a diol obtained by reaction of a diol component such as butane diol with a carbonate compound such as ethylene carbonate. Commercially available products include “PLACCEL CD220PL”, “CD210PL”, “CD205PL”, “CD220”, and “CD210” manufactured by Daicel Chemical Industries, Ltd.
[0011]
Polyol components include the above-mentioned aliphatic polycarbonate diols, ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, decandiol, octadecandiol -A linear diol component such as a glue can also be used. The polybasic acid component to be reacted with such a polyol component has an aliphatic or alicyclic hydrocarbon group having 2 to 20 carbon atoms as a molecular skeleton, and the hydrocarbon group is linear. Or may be branched. Specifically, malonic acid, succinic acid, methyl succinic acid, adipic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, n-hexyladipic acid, tetrahydrophthalic acid, endomethylenetetrahydrophthal Acids and derivatives of these acid anhydrides and esters are used.
[0012]
The acrylic polymer of the B component in the present invention is for improving the initial adhesiveness without impairing the excellent adhesive properties based on the polyester polymer of the A component and the release property of the release liner, A polymer having (meth) acrylic acid alkyl ester having an alkyl group having 4 to 14 carbon atoms as a main monomer and containing substantially no acid component, having a glass transition temperature of −10 ° C. or lower, A polymer having a temperature of −15 ° C. or lower (usually up to about −90 ° C.) is preferably used. Here, substantially not containing an acid component means that an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, itaconic acid, maleic acid or the like is not used as a monomer component. It is intended to prevent corrosion. Moreover, by setting the glass transition temperature to −10 ° C. or lower, it is possible to obtain favorable results for improving the initial adhesiveness, which is the original purpose, as well as adhesive properties such as adhesive strength.
[0013]
The (meth) acrylic acid alkyl ester having an alkyl group having 4 to 14 carbon atoms as the main monomer is a butyl group, isobutyl group, isoamyl group, hexyl group, heptyl group, 2-ethylhexyl group, isooctyl group, isononyl Alkyl ester of (meth) acrylic acid having an alkyl group such as a group, a lauryl group, and an isomyristyl group. Along with this main monomer, as monomers other than unsaturated carboxylic acids, for example, vinyl acetate, styrene, 2-hydroxyethyl (meth) acrylate, (meth) acrylonitrile, etc. are generally used for acrylic adhesives. Known vinyl monomers can also be used in combination. These other monomers are preferably used within the range where the main monomer is 50% by weight or more.
[0014]
The pressure-sensitive adhesive composition of the present invention is usually prepared by separately synthesizing (1) the polyester polymer of component A and the acrylic polymer of component B, and then mixing them together in a lump or solution. Can be prepared. However, in some cases, (2) it may be prepared by any method when the other polymer is polymerized in one polymer, or (3) it may be prepared by any method when both are polymerized simultaneously. Also good.
[0015]
In these preparation methods, the polyester polymer of component A and the acrylic polymer of component B are 50 to 95% by weight, preferably 60 to 90% by weight of the polyester polymer of component A in the total amount of both. %, And the B-component acrylic polymer is 50 to 5% by weight, preferably 40 to 10% by weight. If the polyester polymer of component A exceeds 95% by weight, that is, if the acrylic polymer of component B is less than 5% by weight, the effect of improving the initial tackiness cannot be sufficiently obtained, and the polyester component weight of component A When the coalescence is less than 50% by weight, that is, when the acrylic polymer of the component B exceeds 50% by weight, the adhesive properties and the peelability of the release liner are lowered.
[0016]
The pressure-sensitive adhesive composition of the present invention is mainly composed of the polyester polymer of the component A and the acrylic polymer of the component B. Usually, this is cross-linked and has excellent adhesive properties. Can be. The crosslinking treatment may be performed by adding a polyisocyanate compound, an epoxy compound, an aziridine compound or the like as a crosslinking agent and reacting with this with a functional group such as a hydroxyl group contained in both of the above polymers. In addition to the above-mentioned crosslinking agent, the pressure-sensitive adhesive composition of the present invention, if necessary, a tackifier, an inorganic or organic filler, a powder such as a metal powder or a pigment, a particulate material, a foil-like material, etc. Various conventionally known additives can be included.
[0017]
The pressure-sensitive adhesive sheet of the present invention comprises various plastic films such as polyester film, paper, non-woven fabric, foam, metal foil, laminates thereof, etc. as a support, and the above-mentioned pressure-sensitive adhesive on one or both sides of the support. The layer composed of the adhesive composition is usually provided with a thickness of 10 to 150 μm on one side to form a sheet or tape, and the adhesive surface, that is, the above-mentioned adhesive composition. A release liner is bonded to the surface of the layer from the viewpoint of surface protection and handleability.
[0018]
As the release liner, a release liner that has not been subjected to a silicon treatment can be used, and in particular, a polyolefin-based film is preferably used. As the polyolefin-based film, a film made of polyethylene, polypropylene, polymethylpentene, an ethylene-propylene copolymer or a mixture thereof, a film whose surface is processed with the same polyolefin as described above, and the like can be used.
[0019]
The adhesive sheets of the present invention produced in this way exhibit excellent adhesive properties and excellent initial adhesiveness. Therefore, not only normal adhesive applications but also instantaneous adhesion is required. It can be sufficiently used for applications such as high-speed continuous bonding work and applications where stress is applied immediately after bonding. In addition, since the acrylic polymer used together with the polyester polymer does not substantially contain acidic groups, there is no adverse effect due to acidic groups, and the release liner that is bonded to the adhesive surface is not subjected to silicone treatment. Even with a liner, good releasability can be obtained, so there is no concern about the transfer of silicone to the adhesive surface, and therefore for electronic equipment applications that do not like the presence of acid components or silicone. Can be used without problems.
[0020]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, the scope of the present invention is not restrict | limited at all by the following Examples. In the following, “parts” means parts by weight.
[0021]
Example 1
In a four-necked separable flask equipped with a stirrer, a thermometer and a water separation tube, a liquid polycarbonate diol (trade name “PLACCEL CD220PL” manufactured by Daicel Chemical Industries, Ltd., hydroxyl value: 56. 1 KOH mg / g] 250 parts, sebacic acid 26.6 parts, titanium tetraisopropoxide (hereinafter referred to as TPT) 0.1 part as a catalyst, and in the presence of a small amount of toluene and xylene as reaction water discharge solvents, While starting stirring, the temperature was raised to 180 ° C. and maintained at this temperature. After a while, water outflow separation was observed, and the reaction started to proceed. The reaction was continued for about 25 hours to obtain a polyester polymer solution having a weight average molecular weight of 38,000.
[0022]
Separately, in a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer, 100 parts of toluene as a solvent, 50 parts of isononyl acrylate, 38 parts of ethyl acrylate, 10 parts of methyl methacrylate, acrylic A solution of an acrylic polymer having a glass transition temperature of −41 ° C. and a weight average molecular weight of 450,000 by adding 2 parts of 2-hydroxyethyl acid and 0.2 part of benzoyl peroxide and polymerizing in a nitrogen stream. Got.
[0023]
Next, the polyester polymer solution and the acrylic polymer solution are mixed so as to be 10 parts of the acrylic polymer per 90 parts of the polyester polymer. 3 parts (solid content) of a tolylene diisocyanate adduct of rupropane (trade name “Colonate L” manufactured by Nippon Polyurethane Co., Ltd.) was added and mixed to obtain a solution of an adhesive composition. The pressure-sensitive adhesive composition solution was applied onto a polyethylene terephthalate film having a thickness of 38 μm by an applicator and dried at 120 ° C. for 3 minutes to form a layer of the pressure-sensitive adhesive composition having a thickness of 30 μm. Formed. A polyethylene film having a thickness of 150 μm was bonded to the adhesive surface as a release liner to produce an adhesive tape.
[0024]
Example 2
The polyester polymer solution obtained in Example 1 and the acrylic polymer solution were mixed so that the acrylic polymer was 20 parts per 80 parts of the polyester polymer, and this was further mixed with trimethylolpropane. Tolylene diisocyanate adduct (trade name “Colonate L” manufactured by Nippon Polyurethane Co., Ltd.) 3 parts (solid content) was added and mixed to obtain a solution of the pressure-sensitive adhesive composition. An adhesive tape was prepared in the same manner as in Example 1 using the adhesive composition solution.
[0025]
Example 3
In a four-necked separable flask equipped with a stirrer, a thermometer and a water separation tube, a liquid polycarbonate diol (trade name “PLACCEL CD220PL” manufactured by Daicel Chemical Industries, Ltd., hydroxyl value: 56. 1 KOHmg / g] 250 parts, 24.6 parts azelaic acid and 0.1 part TPT as catalyst were added, and the temperature was raised to 180 ° C. while stirring was started in the presence of a small amount of toluene and xylene as reaction water discharge solvents. Warmed and held at this temperature. After a while, water outflow separation was observed, and the reaction started to proceed. The reaction was continued for about 27 hours to obtain a polyester polymer solution having a weight average molecular weight of 41,000.
[0026]
Separately, in a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 100 parts of toluene as a solvent, 70 parts of n-butyl acrylate, 27 parts of ethyl acrylate, 2-hydroxy acrylate 3 parts of ethyl and 0.2 part of benzoyl peroxide were added and polymerized in a nitrogen stream to obtain an acrylic polymer solution having a glass transition temperature of −46 ° C. and a weight average molecular weight of 380,000.
[0027]
Next, the polyester polymer solution and the acrylic polymer solution are mixed so as to be 30 parts of the acrylic polymer per 70 parts of the polyester polymer. 3 parts (solid content) of a tolylene diisocyanate adduct of rupropane (trade name “Colonate L” manufactured by Nippon Polyurethane Co., Ltd.) was added and mixed to obtain a solution of an adhesive composition. An adhesive tape was prepared in the same manner as in Example 1 using the adhesive composition solution.
[0028]
Comparative Example 1
The polyester polymer solution obtained in Example 1 and the acrylic polymer solution were mixed so that the acrylic polymer was 60 parts per 40 parts of the polyester polymer, and this was further mixed with trimethylolpropane. Tolylene diisocyanate adduct (trade name “Colonate L” manufactured by Nippon Polyurethane Co., Ltd.) 3 parts (solid content) was added and mixed to obtain a solution of the pressure-sensitive adhesive composition. An adhesive tape was prepared in the same manner as in Example 1 using the adhesive composition solution.
[0029]
Comparative Example 2
Into the polyester polymer solution obtained in Example 1, trimethylolpropane hexamethylene diisocyanate adduct (trade name, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent per 100 parts (solid content) of the polyester polymer. “Coronate L”) 3 parts (solid content) was added and mixed to obtain a solution of the pressure-sensitive adhesive composition. An adhesive tape was prepared in the same manner as in Example 1 using the adhesive composition solution.
[0030]
Comparative Example 3
Into the acrylic polymer solution obtained in Example 1, per 100 parts (solid content) of the acrylic polymer, a hexamethylene diisocyanate adduct of trimethylolpropane as a crosslinking agent (trade name of Nippon Polyurethane Co., Ltd.) "Coronate L") 2 parts (solid content) was added and mixed to obtain a solution of the pressure-sensitive adhesive composition. An adhesive tape was prepared in the same manner as in Example 1 using the adhesive composition solution.
[0031]
For each of the adhesive tapes of Examples 1 to 3 and Comparative Examples 1 to 3, the initial adhesive force, the adhesive force, and the release force of the release liner were measured by the following methods. These measurement results were as shown in Table 1.
[0032]
<Initial adhesive strength>
The adhesive tape is cut to a size of 20 mm x 100 mm, the release liner is peeled off in an atmosphere of 23 ° C and 65% RH, and the aluminum plate as the adherend is subjected to 2 kg roller 1 round trip condition Crimped with. Ten seconds later, the 180 ° peel adhesion (Kg / 20 mm width) was measured under the condition of a peel speed of 300 mm / min to obtain the initial adhesive strength.
[0033]
<Adhesive strength>
The 180 ° peel adhesive strength (Kg / 20 mm width) was measured and used as the adhesive strength in the same manner as in the case of the initial adhesive strength, except that the measurement was performed after 30 minutes had elapsed after crimping to the aluminum plate.
[0034]
<Peeling force of peeling liner>
The adhesive tape is cut to a size of 50 mm x 100 mm, the polyethylene terephthalate film side that is the support is fixed to the stainless steel plate with a double-sided tape, and then the adhesive tape is adhesive in an atmosphere of 23 ° C and 65% RH. The peeling force (g / 50 mm width) was measured when the release liner was peeled from the tape at a tensile speed of 300 mm / min.
[0035]

[0036]
As is clear from the results in Table 1 above, each of the adhesive tapes of Examples 1 to 3 of the present invention is excellent in adhesive strength, release liner release property, and initial adhesiveness. Recognize. On the other hand, the pressure-sensitive adhesive tape of Comparative Example 1 in which the amount of the acrylic polymer used is too much is similar to the pressure-sensitive adhesive property of Comparative Example 3 using the acrylic polymer alone. The adhesive tape of Comparative Example 2 using the polyester polymer alone is inferior in the initial adhesiveness.
[0037]
【The invention's effect】
As described above, the present invention has a glass transition temperature of −10 ° C. or less substantially free from an acid component together with a polyester-based polymer containing an aliphatic polycarbonate diol as an essential polyol component. By using a specific amount of this acrylic polymer, it has excellent adhesive strength and initial adhesive strength, and even with a release liner that has not been treated with silicone, such as polyolefin film, good release properties can be obtained. Therefore, there are no problems such as corrosion or malfunction of equipment due to generation of acid components or siloxane gas, and applications that require instantaneous bonding, such as high-speed continuous bonding work. It is possible to provide a pressure-sensitive adhesive composition and its pressure-sensitive adhesive sheet that can be sufficiently used for applications where stress is applied immediately after bonding.

Claims (3)

A) 60 to 90 % by weight of a polyester polymer having an aliphatic polycarbonate diol as an essential polyol component, and B) Acrylic polymer 40 to substantially containing no acid component and having a glass transition temperature of −10 ° C. or lower. A pressure-sensitive adhesive composition comprising 10 % by weight. The pressure-sensitive adhesive composition according to claim 1, wherein the polyester polymer of the component A has a weight average molecular weight of 10,000 or more. A pressure-sensitive adhesive sheet comprising a layer made of the pressure-sensitive adhesive composition according to claim 1 or 2 on one side or both sides of a support.