Dismantlable Adhesives Research Articles

High-molecular-weight polar acrylate block copolymers as high-performance dismantlable adhesive materials in response to photoirradiation and postbaking

Controlled synthesis of block copolymers as dismantlable adhesives using an organotellurium-mediated living radical polymerization (TERP) for discussion of adhesion strength and failure mode.

ラジカル重合による分解性ポリマーの合成と解体性接着材料の設計に関する研究

省エネルギーや廃棄物処理などの低環境負荷の取り組みのため，使用時の高機能化・高性能化と使用後の分解性・解体性を両立できる材料が求められ，問題解決のための新しい技術として，使用後に解体することを予め材料設計や製品設計に組み込んだ解体性接着への関心が高まっている。本論文では，まず解体性接着材料ならびにその技術の概要を示し，分解性ならびに反応性ポリマーを用いた解体性接着材料の開発の詳細について総括的に報告する。著者らが開発してきたポリペルオキシドや反応性のポリアクリル酸エステルブロックコポリマーを粘接着剤として応用して新規な二重刺激応答性の解体性接着材料の設計することで，使用中の粘接着剤の性能安定性と必要に応じて外部刺激を加えることによる容易で迅速な解体の両方が実現できることを示した。高性能粘着特性を有するポリマー材料を設計するための有機テルル化合物を用いるリビングラジカル重合を用いた極性基を含む高分子量アクリル酸エステルブロック共重合体の合成についても報告する。

解体性接着剤の最近の技術動向

接合部の分離が容易に行える解体接着剤について，その最近の動向を取り上げ，解説を行う。このような接着剤は，被接合物の材料リサイクルに役立つのみならず，工作物の仮止めや部品のリワークにも適用できる。熱可塑樹脂の熱溶融を利用する場合が多いが，熱膨張性材料の併用も行われている。近年では，新しい解体因子を用いた接着剤も登場しており，たとえば通電により剥離する接着剤も市販されている。

Organotellurium-Mediated Living Radical Polymerization (TERP) of Acrylates Using Ditelluride Compounds and Binary Azo Initiators for the Synthesis of High-Performance Adhesive Block Copolymers for On-Demand Dismantlable Adhesion

We report the organotellurium-mediated living radical polymerization (TERP) using diphenylditelluride (DT-Ph) and di-n-butylditelluride (DT-Bu) in the presence of a binary azo initiator system consisting of 2,2′-azobis(isobutyronitrile) (AIBN) and 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) (AMVN) with different decomposition rates for the facile synthesis of high-molecular-weight block copolymers containing a polar side group. The block copolymers containing the poly(tert-butyl acrylate) (PtBA) sequence as the reactive segment and the random copolymer sequences of n-butyl acrylate (nBA) or 2-ethylhexyl acrylate (2EHA) with 2-hydroxyethyl acrylate (HEA) as the adhesive segment were synthesized. The concurrent use of the binary initiators was revealed to effectively increase both the polymerization reactivity and the molecular weight of the polymers along with a narrow molecular weight distribution. The produced block copolymers exhibited high performance for the dismantlable adhesion responsible for ...

Thermal behavior and dismantlability of adhesives containing various inorganic salts

As a fundamental study on the development of dismantlable adhesives containing chemically reactive materials, the thermal behavior and dismantlability of an epoxy adhesive containing one of the twenty-seven inorganic salts (chlorides, perchlorates, and nitrates) were observed. In the thermal behavior measured by the differential scanning calorimetry, epoxy adhesives with inorganic salts containing iron, copper, zinc, and aluminum cations released heats of reaction at lower temperatures than the adhesive alone or the adhesives with other inorganic salts. Since such inorganic salts were considered to be effective candidates as fillers in dismantlable adhesives, the adhesion strengths of their mixtures with the adhesive were observed after heat aging at 270 °C for 30 min. The results showed that both chloride and perchlorate salts specifically decreased the adhesion strength after heating. On the other hand, the effect of nitrate salts on the decrease in adhesion strength was low in comparison with the chloride and perchlorate salts.

Precise Synthesis of Acrylic Block Copolymers and Application to On-demand Dismantlable Adhesion Systems in Response to Photoirradiation and Postbaking

Precise Synthesis of Acrylic Block Copolymers and Application to On-demand Dismantlable Adhesion Systems in Response to Photoirradiation and Postbaking

Dismantlement studies of dismantlable polyurethane adhesive by controlling thermal property

This paper investigated the design of dismantlable polyurethane adhesives and dismantling method. To study the dismantlement property of dismantlable polyurethane adhesive by controlling thermal property, we synthesized polyurethane adhesive with various hard segment contents and used thermally expansive microcapsules. The dismantlement of bonded adherend was caused by the expansion of the adhesive layer with the expansion of the thermally expansive microcapsule and softening of the adhesive. For the dismantlement of bonded adherend, the adhesive is needed to have low storage modulus at the expansion temperature of thermally expansive microcapsule. High storage modulus of the adhesive was good for the bonding strength but not for dismantlability. In our study, the dismantlability became better as the hard segment content of adhesive decreased and the bonding strength and heat-resistance were excellent when the hard segment content was more than 25% because of high storage modulus and physical property. Consequently, optimum hard segment content was 25%, which showed excellent adhesion strength and dismantlement of bonded adherend was possible with microwave treatment for 4 min. Using zinc oxide with high dielectric constant could shorten microwave treatment time needed for the dismantlement of the bonded adherend to 3 min by enhancing the heating efficiency of the adhesive.

Facile Synthesis of Main-Chain Degradable Block Copolymers for Performance Enhanced Dismantlable Adhesion

Block copolymers consisting of readily degradable polyperoxides and non-degradable vinyl polymers as the block segments were successfully synthesized by reversible chain transfer catalyzed polymerization, which is one of living radical polymerization techniques. The block copolymers showed characteristic morphology and wettability being different from the polymer blends. When block copolymers containing polyperoxide and polymethacrylate blocks were heated below 150 °C, the polyperoxide blocks were completely degraded and the polymethacrylate blocks were recovered without degradation. Block copolymers containing a poly(2-ethylhexyl methacrylate) block were then investigated as a dismantlable adhesion material, which requires adequate bonding strength during use and easy debonding on demand. Among the several block copolymers, the one consisting of poly(2-ethylhexyl methacrylate) and polyperoxide from methyl sorbate (PPMS) (M(n) = 4900) exhibited good performance as a pressure-sensitive adhesive (PSA). After heating the test specimens in a temperature range from 60 to 100 °C, PSA performance, which was evaluated by 180° peel strength and shear holding power measurements, was significantly diminished. Especially, after heating at 100 °C for 1 h, spontaneous debonding of some test specimens was observed because of the evolution of volatile acetaldehyde from PPMS.

Cohesive Force Change Induced by Polyperoxide Degradation for Application to Dismantlable Adhesion

Polyperoxides containing peroxy bonds as the main-chain repeating units are a new class of degradable polymers because of significant changes in their molecular weight and physical properties during a degradation process. In this study, the application of linear and network polyperoxides to dismantlable adhesion was investigated. When the linear polyperoxide obtained from methyl sorbate and oxygen (PP-MS) was used as a pressure-sensitive adhesive (PSA), its shear holding power and 180° peel strength immediately decreased upon heating at 70 °C or under UV irradiation. Low-molecular-weight products, which were generated by the degradation of PP-MS, behaved as a plasticizer to effectively reduce the cohesive force. The adhesive properties of two types of polyperoxides-based network polymers, the cross-linking point and main-chain degradable network polymers, were evaluated. A cross-linking point degradable network polymer was produced by the oxygen cross-linking of dienyl-functionalized poly(ethylene glycol). A main-chain degradable network polymer was formed by the diisocyanate cross-linking of a hydroxy-functionalized polyperoxide. Both network polymers showed a higher adhesive strength than PP-MS due to their three-dimensional network structure. Noteworthy, the adhesive strength of the main-chain degradable network polymer was varied from the level of PSA to structural adhesives by increasing the added amount of the diisocyanate cross-linker. After heating at 110 °C, the cohesive and adhesive strengths significantly decreased. The linear and network polyperoxides are shown to be promising materials for dismantlable adhesion.

J0403-1-3 熱膨張性マイクロカプセル混入接着剤に生じる残留応力の有限要素解析([J0403-1]締結・接合部の力学と評価(1):接着接合)

Adhesive joints have a lot of merits. For instance, it is easy to bond different types of materials and realize light weight structures. However, the bonded adherend has been difficult to be recycled. Currently, dismantlable adhesives that can be separated by a trigger have been developed. In this case, the adherends are recyclable. The adhesives include thermally expansive microcapsules (TEM). However, some properties of TEM are still unknown. In this research, the effect of the size and position of TEM in adhesives is studied using FEA.

An induction heating method with traveling magnetic field for long structure metal

AbstractA novel dismantlable adhesion method for recycling operation of interior materials is proposed. This method applies a high‐frequency induction heating (IH) and a thermoplastic adhesive. For adhesion of interior materials to long steel studs, a conventional spiral coil such as IH cooking heater is inadequate for uniform heating to the stud. Therefore, we have proposed an induction heating method with traveling magnetic field for perfect long structure bonding. In this paper, we describe the new adhesion method using a 20‐kHz, three‐phase 200‐V inverter and linear induction coil. From induction heating characteristics to thin steel plates and long studs, the method demonstrates its usefulness for uniform heating to long structures. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(4): 32–39, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20833

ポリマー分野におけるエコ対応―２ 環境対応の接着―解体性接着剤の技術動向―

Current technical trends on dismantlable adhesion are summarized in the article. The adhesives are useful for the adherend material recycling because their joints can be separated after use. Many dismantlable adhesives having novel dismantlement factors have recently been developed. An adhesive including thermally expansive fillers is the most typical one. An electrically separating adhesive and thermally melting adhesives, for instance, are also developed and become widely used in these days. Another adhesive, which we developed, can resist high temperature and has high strength by the combination of changing thermally expansive fillers and resin modification that is suitable for dismantlable adhesives. It seems that new generation of dismantlable adhesives, for which electrochemical phenomena and surface physics are utilized, will be realized in the future.

解体性接着技術－最近の進展－

解体性接着技術－最近の進展－

平面加熱のための移動磁界方式誘導加熱の試み

As one of the effective dismantlable adhesion method, the ALLOVER method for interior construction using induction heating and thermoplastic adhesive has been proposed. And the uniform heating method to straight steel stud with induction heating applied 3-phase traveling magnetic field using linear induction coils was also proposed. This paper describes the experiments and analysis for uniform heating to extended heating area of flat metals using desired several induction coils. The proposed coil winding methods for uniform heating to wide heating area may be applied not only interior works of tiles or floorboards but also industrial part's heating.

小形誘導加熱におけるコア付集中巻コイルの試み

As an interior construction, a dismantlable adhesion method using induction heating (IH) and thermoplastic adhesive has been proposed. The method is called “the allover method”. But when a distance between an induction coil for generating EMF and heated metal is existed considerably, the conventional induction coil couldn't heat the metal sufficiently. That is, heating characteristics of the metal depend on the distance. In this paper, a new heating coil with concentrated winding having ferrate core is experimented. From experiments, an electric equivalent circuit is deduced, and heating characteristics of heated metal at the distances are analyzed. The usefulness of concentrated winding coil is cleared by analyzed characteristics.

An Induction Heating Method with Traveling Magnetic Field for Long Structure Metal

A novel dismantlable adhesion method for recycling operation of interior materials is proposed. This method is applied a high frequency induction heating and a thermoplastic adhesive. For an adhesion of interior material to long steel stud, a conventional spiral coil as like IH cooking heater gives inadequateness for uniform heating to the stud. Therefore, we have proposed an induction heating method with traveling magnetic field for perfect long structures bonding. In this paper, we describe on the new adhesion method using the 20kHz, three-phase 200V inverter and linear induction coil. From induction heating characteristics to thin steel plates and long studs, the method is cleared the usefulness for uniform heating to long structures.

解体性と耐熱性を兼備した構造用接着剤の組成設計

耐熱接着性と加熱解体性を兼備する構造用エポキシ樹脂接着剤の組成設計を試みた。イミド骨格を有する高極性単官能エポキシ（グリシジルフタルイミド: GPI) をビスフェノールA型エポキシ樹脂に配合することにより，他の単官能エポキシ添加系と比較して硬化樹脂の Tg 低下を抑制しつつ Tg を越えた温度域での軟化が大きくなり，ゴム平坦域弾性率を効果的に低下させうることを見出した。また，同エポキシ組成であっても硬化剤種によって熱軟化挙動は異なり，潜在性硬化触媒ジシアンジアミド／ジクロロフェニルジメチルウレアは，Tg 低下抑制効果と熱軟化効果のバランスに優れた硬化物を与えた。これらの知見を基に，80℃以上の Tg，3GPa以上のガラス領域樹脂弾性率を保ちつつ，ゴム状平坦域弾性率を約 2MPa にまで低下させ得る GPI 25%含有エポキシ樹脂組成物を得た。さらに，上記樹脂組成物に膨張黒鉛を 10%添加することにより，80℃せん断接着強さが 20MPa という構造材適用レベルの耐熱接着性を有し，かつ，膨張黒鉛の熱膨張により加熱解体する解体性接着剤組成を見出した。

つけてはがす高分子 解体性接着剤の技術と応用

つけてはがす高分子 解体性接着剤の技術と応用

移動磁界コイルを用いた誘導加熱接着装置の研究

“The allover method” using induction heating and thermoplastic adhesive is the effective dismantlable adhesion method for interior constructions, because of the advantage to facilitate recycling, reduce a sick house syndrome and easy work. Authors are studying on the new heating coil for adhesion and dismantling at the constructions. This paper describes a linear induction coil with traveling magnetic field for long structures.

Bond strength and disbonding behavior of elastomer and emulsion-type dismantlable adhesives used for building materials

A new form of dismantlable adhesive technology has been developed. This is a revolutionary development in the construction industry, which makes it possible for the bonded building materials to be separated by the simple application of heating over100°C.This article describes the design of dismantlable adhesives (elastomer type and emulsion type) and the evaluation of uses for building materials. The weight fraction of thermally expansive particles from 5% to 15% is suitable for both bond strength and dismantlement of joints. The bond strength of joints could not decrease after durability test at 60°C–95% RH for 30days, and then the joints were separated easily by heating from 150 to 180°C.At this technology, manufacturing is equal to conventional adhesives and time of heating for dismantlement is quite short, so it is efficient for not only performance (adhesion and dismantlement), but also manufacturing and cost.