JP4732792B2 - Water-dispersed acrylic pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet - Google Patents
Water-dispersed acrylic pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet Download PDFInfo
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Description
本発明は、水分散型アクリル系粘着剤組成物に関し、さらに詳しくは、透明性を有し、高凝集力であり、かつ耐熱性に優れた粘着シートを提供しうる水分散型アクリル系粘着剤組成物に関するものである。
The present invention relates to a water-dispersed acrylic pressure-sensitive adhesive composition, and more specifically, a water-dispersed acrylic pressure-sensitive adhesive that can provide a pressure-sensitive adhesive sheet having transparency, high cohesive force, and excellent heat resistance. It relates to a composition.
これまで、有機溶剤溶液型のアクリル系粘着剤組成物を用いた様々な粘着シートが開発されてきたが、最近では、環境問題の点より、有機溶剤を用いない水分散型のアクリル系粘着剤組成物が注目されている。
また、粘着剤組成物の用途が多岐にわたり、粘着剤組成物には透明で高凝集力や耐熱性を有するものも要求されるようになってきている。
Various adhesive sheets using organic solvent solution type acrylic adhesive compositions have been developed so far, but recently, water dispersion type acrylic adhesives that do not use organic solvents due to environmental problems. Compositions are drawing attention.
In addition, the pressure-sensitive adhesive composition has various uses, and the pressure-sensitive adhesive composition is required to be transparent and have high cohesive strength and heat resistance.
凝集力や耐熱性を改善する方法として、粘着剤組成物に層状粘土鉱物を分散させる方法が知られている（特許文献１参照）。この方法は、光重合タイプの粘着剤組成物に関するものであり、この方法を水分散型粘着剤組成物に適用しても、層状粘土鉱物が核となる凝集物が発生するという問題があった。
また、水分散型粘着剤ポリマーの合成時に層状粘土鉱物を添加する方法が知られている（特許文献２参照）。しかし、この方法は、粘着剤ポリマーの製造工程が複雑になる上、凝集物の発生を免れず、またこれより得られる粘着シートは透明性に劣る。
A method of adding a layered clay mineral during the synthesis of a water-dispersed pressure-sensitive adhesive polymer is known (see Patent Document 2). However, this method complicates the production process of the pressure-sensitive adhesive polymer, unavoidably generates aggregates, and the pressure-sensitive adhesive sheet obtained therefrom is inferior in transparency.
このように、従来の技術では、水分散型粘着剤組成物中に凝集物を発生することなく層状粘土鉱物を添加することは容易ではなく、所望の凝集力や耐熱性が得られなかったり、透明性が不十分となる等の問題を有していた。
また、本発明者らは、水分散型アクリル系粘着剤組成物中に層状粘土鉱物を添加するにあたり、スチレン−マレイン酸共重合体の部分エステル化物等からなる特定の界面活性剤を使用すると、層状粘土鉱物が核となる凝集物の発生を防止できることを、既に見出しているが、この場合、透明性が低下する問題があった。
Thus, in the prior art, it is not easy to add a layered clay mineral without generating aggregates in the water-dispersed pressure-sensitive adhesive composition, and the desired cohesive force and heat resistance cannot be obtained, There were problems such as insufficient transparency.
In addition, when adding a layered clay mineral to the water-dispersed acrylic pressure-sensitive adhesive composition, the present inventors use a specific surfactant composed of a partially esterified product of a styrene-maleic acid copolymer. Although it has already been found that the generation of agglomerates in which the layered clay mineral is a core can be prevented, in this case, there is a problem that transparency is lowered.
本発明は、このような事情に照らし、水分散型粘着剤組成物中に層状粘土鉱物を凝集物を発生することなく簡単に分散させることができ、これにより高凝集力で耐熱性に優れ、しかも透明性にも優れた粘着剤組成物を得ることを課題としている。
In light of such circumstances, the present invention can easily disperse the layered clay mineral in the water-dispersed pressure-sensitive adhesive composition without generating aggregates, and thereby has high cohesive force and excellent heat resistance, In addition, it is an object to obtain a pressure-sensitive adhesive composition having excellent transparency.
本発明者らは、上記の課題に対して、鋭意検討を重ねた結果、特定の分散剤を溶解した水溶液に有機化処理された（親油化された）層状粘土鉱物を加えて分散させ、この分散液をアクリル系粘着剤組成物中に添加することにより、層状粘土鉱物を凝集物を発生することなく分散可能で、これより得られる粘着シートは高凝集力で耐熱性に優れ、しかも透明性にも優れていることを見出し、本発明を完成するに至った。
As a result of intensive studies on the above problems, the present inventors added an organically treated (oleophilic) layered clay mineral to an aqueous solution in which a specific dispersant is dissolved, and dispersed, By adding this dispersion to the acrylic pressure-sensitive adhesive composition, the layered clay mineral can be dispersed without generating agglomerates, and the resulting pressure-sensitive adhesive sheet has high cohesive strength, excellent heat resistance, and transparency. As a result, the present invention has been completed.
すなわち、本発明は、（ａ）炭素数４〜１４個のアルキルアルコールの（メタ）アクリル酸アルキルエステルを主成分とするビニル系モノマー９０〜９９重量％と極性基含有モノマー１０〜１重量％とのアクリル系共重合体の水分散体中に、上記アクリル系共重合体１００重量部あたり、（ｂ）親水性官能基を有する有機カチオンで有機化処理された層状粘土鉱物１〜２０重量部が、（ｃ）リン酸系分散剤０．１〜５重量部の存在下、分散されている水分散型アクリル系粘着剤組成物の製造方法において、（ｃ）成分のリン酸系分散剤の水溶液に、（ｂ）成分の親水性官能基を有する有機カチオンで有機化処理された層状粘土鉱物を加えて分散させ、この分散液を、（ａ）成分のアクリル系共重合体の水分散体中に加えて混合分散することを特徴とする水分散型アクリル系粘着剤組成物の製造方法に係るものである。
特に、本発明は、（ｂ）成分の親水性官能基を有する有機カチオンで有機化処理された層状粘土鉱物がスメクタイト系である上記構成の水分散型アクリル系粘着剤組成物の製造方法、（ｂ）成分における親水性官能基を有する有機カチオンが水酸基含有の４級アンモニュウム塩である上記構成の水分散型アクリル系粘着剤組成物の製造方法、（ｃ）成分のリン酸系分散剤がヘキサメタリン酸ナトリウムである上記構成の水分散型アクリル系粘着剤組成物の製造方法を提供できるものである。
That is, the present invention includes (a) 90 to 99% by weight of a vinyl-based monomer having a main component of a (meth) acrylic acid alkyl ester of an alkyl alcohol having 4 to 14 carbon atoms and 10 to 1% by weight of a polar group-containing monomer. (B) 1 to 20 parts by weight of a layered clay mineral that has been organically treated with an organic cation having a hydrophilic functional group per 100 parts by weight of the acrylic copolymer. (C) In the method for producing a water-dispersed acrylic pressure-sensitive adhesive composition dispersed in the presence of 0.1 to 5 parts by weight of a phosphoric acid-based dispersant, an aqueous solution of the phosphoric acid-based dispersant as the component (c) In addition, a layered clay mineral organically treated with an organic cation having a hydrophilic functional group as component (b) is added and dispersed, and this dispersion is dispersed in an aqueous dispersion of the acrylic copolymer as component (a). In addition to mixing and dispersing Those of the method of producing a water-dispersible acrylic pressure-sensitive adhesive composition according to symptoms.
In particular, the present invention is, (b) method for producing a component of the hydrophilic functional groups the arrangement of water-dispersible accession Li Le-based pressure-sensitive adhesive composition organically treated layered clay mineral with organic cation is a smectite having And (b) a method for producing a water-dispersed acrylic pressure-sensitive adhesive composition having the above structure, wherein the organic cation having a hydrophilic functional group in the component is a hydroxyl group-containing quaternary ammonium salt, and (c) a phosphoric acid-based dispersant as the component. Can provide a method for producing a water-dispersed acrylic pressure-sensitive adhesive composition having the above-described structure, wherein is sodium hexametaphosphate .
さらに、本発明は、支持体または剥離性支持体上に、上記各構成の方法で製造された水分散型アクリル系粘着剤組成物を塗布乾燥した粘着剤層を有することを特徴とする粘着シートに係るものである。特に、上記の粘着剤層が、２０μｍ厚での全光線透過率が９０〜１００％、ヘイズが０〜２％である上記構成の粘着シートを提供できるものである。
なお、本明細書にいう「粘着シート」には、シート状物のほか、テープ状物も含まれ、その他、ラベル状物等の公知の各種の粘着製品が含まれるものである。
Furthermore, the present invention has a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer obtained by applying and drying a water-dispersed acrylic pressure-sensitive adhesive composition produced by the method of each of the above-described structures on a support or a peelable support. It is related to. In particular, the above-mentioned pressure-sensitive adhesive layer can provide a pressure-sensitive adhesive sheet having the above-described structure having a total light transmittance of 90 to 100% and a haze of 0 to 2% at a thickness of 20 μm.
The “pressure-sensitive adhesive sheet” referred to in the present specification includes not only a sheet-like material but also a tape-like material, and various other known pressure-sensitive adhesive products such as a label-like material.
このように、本発明においては、水分散型アクリル系粘着剤組成物中に層状粘土鉱物を凝集物を発生することなく簡単に分散させることが可能であり、この水分散型アクリル系粘着剤組成物を使用することにより、従来では困難であった、高凝集力で耐熱性に優れ、しかも透明性にも優れる粘着シートを提供することができる。
Thus, in the present invention, the layered clay mineral can be easily dispersed in the water-dispersed acrylic pressure-sensitive adhesive composition without generating aggregates. By using the product, it is possible to provide a pressure-sensitive adhesive sheet having high cohesion, excellent heat resistance and excellent transparency, which has been difficult in the past.
本発明において、（ａ）成分のアクリル系共重合体の水分散体は、炭素数４〜１４個のアルキルアルコールの（メタ）アクリル酸アルキルエステルを主成分とするビニル系モノマーと極性基含有モノマーとのモノマー混合物を、通常の水分散重合法、例えば、乳化重合法、懸濁重合法等により共重合させることにより、得られるものである。
この水分散体におけるアクリル系共重合体の平均粒径は、特に限定されないが、シート化した際に良好な特性を得るため、適宜の範囲に設定されているのが望ましい。例えば、乳化重合法では０．１〜５０μｍ、好適には０．２〜１μｍ、懸濁重合法では１〜１００μｍ、好適には１０〜８０μｍであるのがよい。
In the present invention, the aqueous dispersion of the acrylic copolymer of the component (a) is composed of a vinyl monomer and a polar group-containing monomer, the main component of which is a (meth) acrylic acid alkyl ester of an alkyl alcohol having 4 to 14 carbon atoms. Is obtained by copolymerizing the monomer mixture with a conventional water dispersion polymerization method such as an emulsion polymerization method or a suspension polymerization method.
The average particle size of the acrylic copolymer in the aqueous dispersion is not particularly limited, but is desirably set within an appropriate range in order to obtain good characteristics when formed into a sheet. For example, the emulsion polymerization method may be 0.1 to 50 μm, preferably 0.2 to 1 μm, and the suspension polymerization method may be 1 to 100 μm, preferably 10 to 80 μm.
モノマー混合物において、ビニル系モノマーの主成分である炭素数４〜１４個のアルキルアルコールの（メタ）アクリル酸アルキルエステルには、ブチル基、イソブチル基、ペンチル基、イソペンチル基、ヘキシル基、プチル基、オクチル基、イソオクチル基、ノニル基、イソノニル基、デシル基、イソデシル基等のアルキル基を有するアクリル酸またはメタクリル酸のアルキルエステルが挙げられる。
これらのモノマーのほかに、モノマー全体の３０重量％以下の割合で、共重合可能な他のビニル系モノマーを併用してもよい。具体的には、上記炭素数以外のアルキルアルコールの（メタ）アクリル酸アルキルエステルや、酢酸ビニル、スチレンやその誘導体、（メタ）アクリロニトリル、（メタ）アクリルアミド等が挙げられる。
上記のビニル系モノマーと共に、必須成分として用いられる極性基含有モノマーには、（メタ）アクリル酸、イタコン酸、２−アクリルアミドプロパンスルホン酸等の酸基含有モノマー、２−ヒドロキシエチル（メタ）アクリレート、２−ヒドロキシプロピル（メタ）アクリレート等の水酸基含有モノマー等が挙げられる。
In the monomer mixture, the alkyl alcohol (meth) acrylic acid alkyl ester having 4 to 14 carbon atoms, which is the main component of the vinyl monomer, includes a butyl group, an isobutyl group, a pentyl group, an isopentyl group, a hexyl group, a ptyl group, Examples thereof include alkyl esters of acrylic acid or methacrylic acid having an alkyl group such as an octyl group, an isooctyl group, a nonyl group, an isononyl group, a decyl group, and an isodecyl group.
In addition to these monomers, other copolymerizable vinyl monomers may be used in combination at a ratio of 30% by weight or less of the total monomers. Specific examples include (meth) acrylic acid alkyl esters of alkyl alcohols other than the above carbon number, vinyl acetate, styrene and its derivatives, (meth) acrylonitrile, (meth) acrylamide, and the like.
Along with the above vinyl monomers, polar group-containing monomers used as essential components include acid group-containing monomers such as (meth) acrylic acid, itaconic acid, 2-acrylamidopropanesulfonic acid, 2-hydroxyethyl (meth) acrylate, Examples thereof include hydroxyl group-containing monomers such as 2-hydroxypropyl (meth) acrylate.
モノマー混合物において、炭素数４〜１４個のアルキルアルコールの（メタ）アクリル酸アルキルエステルを主成分とするビニル系モノマーと極性基含有モノマーとの使用割合は、前者のビニル系モノマーが９０〜９９重量％、特に好ましくは９４〜９８重量％で、後者の極性基含有モノマーが１０〜１重量％、特に好ましくは６〜２重量％であるのがよい。後者の極性基含有モノマーが１重量％未満となると層状粘土鉱物との十分な相互作用を得られず、凝集力や耐熱性が低下し、また１０重量％を超えると増粘し、やはり好ましい特性が得られない。
In the monomer mixture, the proportion of the vinyl monomer having a main component of the alkyl alcohol (meth) acrylic acid alkyl ester having 4 to 14 carbon atoms and the polar group-containing monomer is 90 to 99 weights of the former vinyl monomer. %, Particularly preferably 94 to 98% by weight, the latter polar group-containing monomer being 10 to 1% by weight, particularly preferably 6 to 2% by weight. If the latter polar group-containing monomer is less than 1% by weight, sufficient interaction with the layered clay mineral cannot be obtained, cohesive strength and heat resistance are reduced, and if it exceeds 10% by weight, the viscosity is increased, which is also preferable characteristics. Cannot be obtained.
本発明において、（ｂ）成分の有機化処理された層状粘土鉱物は、結晶構造中に交換性陽イオンを有する層状珪酸塩鉱物を、カチオン性界面活性剤等で親油化処理することにより、有機化処理されたものである。
層状珪酸塩鉱物には、モンモリロナイト、サポナイト、ヘクトライト スチーブンサイト等のスメクタイト系粘土鉱物、フッ素四ケイ素雲母等のマイカ系粘土鉱物が挙げられ、１種または２種以上を併用することができる。これらの中でも、スメクタイト系粘土鉱物が特に好ましく用いられる。
層状粘土鉱物の形状は、シリケート１枚の厚さが約１ｎｍで、幅方向の最大長が１００ｎｍ以下、好ましくは６０ｎｍ以下の板状である。１００ｎｍを超えると透明性が低下する。ここで言う形状は化学構造からの理論長であり、実測値ではない。
In the present invention, the layered clay mineral subjected to the organic treatment of the component (b) is obtained by subjecting the layered silicate mineral having an exchangeable cation in the crystal structure to a lipophilic treatment with a cationic surfactant or the like, Organically treated.
Examples of the layered silicate minerals include smectite clay minerals such as montmorillonite, saponite, and hectorite stevensite, and mica clay minerals such as fluorotetrasilicon mica, and one or more of them can be used in combination. Among these, smectite clay minerals are particularly preferably used.
The shape of the layered clay mineral is a plate shape in which the thickness of one silicate is about 1 nm and the maximum length in the width direction is 100 nm or less, preferably 60 nm or less. When it exceeds 100 nm, the transparency is lowered. The shape here is the theoretical length from the chemical structure, not the actual measurement.
交換性陽イオンとは、層状粘土鉱物の結晶層の表面に存在するナトリウムやカリウム等の金属イオンのことである。これらのイオンは親水性であるため、未処理の層状粘土鉱物を水に分散すると、層間に水が浸入膨潤してゲル化し、層状粘土鉱物の分散液をアクリル系共重合体の水分散体中へ分散させるのが困難になる。
そこで、この交換性陽イオンを親油性のカチオン性界面活性剤等でイオン交換することが必要になる。このようなカチオン性界面活性剤には、４級（アルキル）アンモニュウム塩、４級（アルキル）ホスニュウム塩等があり、特に末端に水酸基等の親水性官能基を含有しているものが用いられる。親水性官能基を含有しないカチオン性界面活性剤は、層状粘土鉱物の層間が親油性になり、水中で分散させることができない。
The exchangeable cation is a metal ion such as sodium or potassium existing on the surface of the crystal layer of the layered clay mineral. Since these ions are hydrophilic, when the untreated layered clay mineral is dispersed in water, water penetrates and swells between the layers and gels, and the dispersion of the layered clay mineral is dispersed in the aqueous dispersion of the acrylic copolymer. It becomes difficult to disperse into
Therefore, it is necessary to ion-exchange this exchangeable cation with a lipophilic cationic surfactant or the like. Such cationic surfactants include quaternary (alkyl) ammonium salts, quaternary (alkyl) phosphine salts, and the like, and in particular, those containing a hydrophilic functional group such as a hydroxyl group at the terminal are used. The cationic surfactant that does not contain a hydrophilic functional group becomes lipophilic between the layers of the layered clay mineral and cannot be dispersed in water.
親水性官能基を含有する有機カチオンを層間に導入することにより、水中でゲル化することなく層状粘土鉱物を分散することが可能になる。このような親水性官能基を含有する有機カチオンには、水酸基含有の４級（アルキル）アンモニュウム塩があり、例えば、プロピレンオキサイド骨格を有するアンモニュウム塩を挙げられる。
このように有機化処理剤として水酸基を含有するものを使用することにより、アクリル系共重合体における極性基含有モノマーに由来する極性基と相互作用して、粘着剤組成物に耐熱性を付与する相乗効果もある。
層状粘土鉱物を上記のように有機化処理するにあたり、その有機化処理量は、特に限定されないが、８０〜２４０モル当量／１００ｇであるのが好ましい。
By introducing an organic cation containing a hydrophilic functional group between layers, the layered clay mineral can be dispersed without gelation in water. Examples of the organic cation containing such a hydrophilic functional group include a quaternary (alkyl) ammonium salt containing a hydroxyl group, and examples thereof include an ammonium salt having a propylene oxide skeleton.
Thus, by using what contains a hydroxyl group as an organic processing agent, it interacts with the polar group derived from the polar group containing monomer in an acrylic copolymer, and gives heat resistance to an adhesive composition. There is also a synergistic effect.
When the layered clay mineral is subjected to the organic treatment as described above, the amount of the organic treatment is not particularly limited, but is preferably 80 to 240 molar equivalent / 100 g.
本発明において、（ｂ）成分の有機化処理された層状粘土鉱物の使用量は、（ａ）成分の水分散体を構成するアクリル系共重合体１００重量部あたり、１〜２０重量部、好ましくは３〜１５重量部、さらに好ましくは４〜１０重量部とするのがよい。
（ｂ）成分の層状粘土鉱物が１重量部未満となると、この層状粘土鉱物に基づく高凝集力や優れた耐熱性等が得られず、また２０重量部を超えると、粘着剤組成物が増粘して、塗布外観が低下する等の不具合が生じやすい。
In the present invention, the amount of the layered clay mineral subjected to the organic treatment of the component (b) is preferably 1 to 20 parts by weight per 100 parts by weight of the acrylic copolymer constituting the aqueous dispersion of the component (a), preferably Is 3 to 15 parts by weight, more preferably 4 to 10 parts by weight.
When the amount of the layered clay mineral (b) is less than 1 part by weight, high cohesive force or excellent heat resistance based on the layered clay mineral cannot be obtained, and when the amount exceeds 20 parts by weight, the pressure-sensitive adhesive composition increases. It tends to cause problems such as sticking and deterioration of the coating appearance.
本発明において、（ｃ）成分のリン酸系分散剤は、（ｂ）成分の有機化処理された層状粘土鉱物をアクリル系共重合体の水分散体中に凝集物を発生させることなく透明な状態まで良好に分散させる働きを有している。すなわち、（ｃ）成分のリン酸系分散剤は、低分子であるため、（ｂ）成分の層状粘土鉱物の微粒子一粒一粒に吸着し斥力により、粒子の凝集を抑制することができる。また（ｃ）成分のリン酸系分散剤は嵩高いので、立体障害による粒子の凝集を防ぐ効果も期待できる。
これに対して、スチレン−マレイン酸共重合体の部分エステル化物等の分散剤を使用すると、これが高分子で分子鎖が長いため、層状粘土鉱物の微粒子を擬似架橋する傾向があり、層状粘土鉱物を透明な状態まで分散させにくい。
In the present invention, the phosphoric acid-based dispersant of component (c) is transparent without generating an aggregate in the aqueous dispersion of the acrylic copolymer of the layered clay mineral subjected to the organic treatment of component (b). It has the function of dispersing well to the state. That is, since the phosphoric acid dispersant of component (c) has a low molecular weight, it can be adsorbed to each fine particle of the layered clay mineral of component (b) and suppress particle aggregation by repulsion. Moreover, since the phosphoric acid type | system | group dispersing agent of (c) component is bulky, the effect which prevents the aggregation of the particle | grains by a steric hindrance can also be anticipated.
On the other hand, when a dispersant such as a partially esterified product of styrene-maleic acid copolymer is used, this is a polymer and has a long molecular chain. Is difficult to disperse to a transparent state.
（ｃ）成分のリン酸系分散剤には、オルソリン酸ナトリウム、ピロリン酸ナトリウム、トリポリリン酸ナトリウム、テトラリン酸ナトリウム、ヘキサメタリン酸ナトリウム、リン酸三ナトリウム等があり、特にヘキサメタリン酸ナトリウムが好ましい。
このような（ｃ）成分のリン酸系分散剤の使用量は、（ａ）成分の水分散体を構成するアクリル系共重合体１００重量部あたり、０．１〜５重量部、好ましくは０．３〜３重量部であり、さらに好ましくは０．５〜２重量部とするのがよい。（ｃ）成分のリン酸系分散剤が０．１重量部未満では効果がなく、凝集物が発生する傾向にあり、５重量部を超えると層状粘土鉱物の分散性が著しく低下する傾向にある。
Examples of the phosphoric acid dispersant as component (c) include sodium orthophosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium tetraphosphate, sodium hexametaphosphate, trisodium phosphate, and sodium hexametaphosphate is particularly preferable.
The amount of the phosphoric acid dispersant as the component (c) used is 0.1 to 5 parts by weight, preferably 0, per 100 parts by weight of the acrylic copolymer constituting the aqueous dispersion of the component (a). .3 to 3 parts by weight, more preferably 0.5 to 2 parts by weight. If the phosphoric acid dispersant of component (c) is less than 0.1 parts by weight, there is no effect and agglomerates tend to be generated, and if it exceeds 5 parts by weight, the dispersibility of the layered clay mineral tends to be significantly reduced. .
本発明においては、（ｂ）成分の有機化処理された層状粘土鉱物と（ｃ）成分のリン酸系分散剤を使用して、層状粘土鉱物の水分散液を調製する。この方法は、特に限定されないが、通常は、（ｃ）成分のリン酸系分散剤の水溶液をつくり、これに（ｂ）成分の有機化処理された層状粘土鉱物を加えて分散させればよい。
具体的には、水１００重量部にリン酸系分散剤０．１〜５重量部を加えて撹拌し、分散剤水溶液をつくる。これに有機化処理された層状粘土鉱物１〜２０重量部を加える。水分散液中の層状粘土鉱物の濃度は特に限定されないが、５〜２０重量％が望ましい。
層状粘土鉱物を加えたのち、放置して、層状粘土鉱物を十分に膨潤させ、層状粘土鉱物の層間距離を広げて、分散しやすくするのが望ましい。この膨潤に要する時間としては、特に限定されないが、放置温度が２３℃であれば３時間以上、好ましくは１２時間以上、さらに好ましくは２４時間以上必要である。
In the present invention, an aqueous dispersion of a layered clay mineral is prepared using an organically treated layered clay mineral of component (b) and a phosphoric acid dispersant of component (c). This method is not particularly limited, but usually, an aqueous solution of the phosphoric acid dispersant as the component (c) is prepared, and the layered clay mineral subjected to the organic treatment as the component (b) is added thereto and dispersed. .
Specifically, 0.1 to 5 parts by weight of a phosphoric acid dispersant is added to 100 parts by weight of water and stirred to form a dispersant aqueous solution. To this is added 1 to 20 parts by weight of an organically treated layered clay mineral. The concentration of the layered clay mineral in the aqueous dispersion is not particularly limited, but is preferably 5 to 20% by weight.
After adding the layered clay mineral, it is desirable that the layered clay mineral is allowed to swell sufficiently so that the layered clay mineral is sufficiently swollen and the interlayer distance of the layered clay mineral is increased to facilitate dispersion. The time required for this swelling is not particularly limited, but it is 3 hours or longer, preferably 12 hours or longer, more preferably 24 hours or longer if the standing temperature is 23 ° C.
このように膨潤させたのち、超音波分散機やホモミキサー等の適宜の分散機を用いて、層状粘土鉱物のシリケート層を剥離分散する。
層状粘土鉱物は通常シリケート層が何層にも重なった構造をしているので、層状粘土鉱物のシリケート層の平均重なりが６層以下になるまで分散するのが好ましい。６層を超えると層状粘土鉱物の総表面積が低下し、有機成分との相互作用が低下し粘着剤の強靭性が低下する。平均重なりの分析は、電子顕微鏡（ＴＥＭ）にて行うことができる。
このようにして得られる分散液は、液中の層状粘土鉱物の平均粒径が２００ｎｍ以下、好ましくは１５０ｎｍ以下になるまで分散されているのがよい。平均粒径が２００ｎｍを超えると、透明性が著しく低下する。
After swelling in this way, the silicate layer of the layered clay mineral is peeled and dispersed using an appropriate dispersing machine such as an ultrasonic dispersing machine or a homomixer.
Since the layered clay mineral usually has a structure in which the silicate layers overlap each other, it is preferable that the layered clay mineral is dispersed until the average overlap of the silicate layers of the layered clay mineral becomes 6 layers or less. When it exceeds six layers, the total surface area of the layered clay mineral is reduced, the interaction with the organic component is reduced, and the toughness of the adhesive is reduced. The average overlap analysis can be performed with an electron microscope (TEM).
The dispersion liquid thus obtained is preferably dispersed until the average particle size of the layered clay mineral in the liquid is 200 nm or less, preferably 150 nm or less. When the average particle size exceeds 200 nm, the transparency is remarkably lowered.
本発明においては、このようにして得られる層状粘土鉱物の水分散液を、（ａ）成分のアクリル系共重合体の水分散体中に加えて、適宜の方法で混合分散させることにより、本発明の水分散型アクリル系粘着剤組成物を調製する。
混合分散の方法は特に限定されないが、超音波等のハイパワー分散装置で分散を行うとアクリル系共重合体の水分散体由来の凝集物が発生する傾向があるため、ディスパー等を使用してこのような凝集物の発生を防ぐのが望ましい。
なお、上記の調製にあたり、粘着力の向上等の目的のため、透明性が低下しない限り、種々の添加剤を配合することができる。この添加剤は、（ａ）成分のアクリル系共重合体の水分散体中に添加しておいてもよいし、上記層状粘土鉱物の水分散液の混合分散時に、同時にまたは逐次的に添加するようにしてもよい。
In the present invention, the aqueous dispersion of the layered clay mineral thus obtained is added to the aqueous dispersion of the acrylic copolymer of component (a) and mixed and dispersed by an appropriate method. The water-dispersed acrylic pressure-sensitive adhesive composition of the invention is prepared.
The method of mixing and dispersing is not particularly limited, but if dispersion is performed with a high-power dispersing device such as ultrasonic waves, aggregates derived from an aqueous dispersion of an acrylic copolymer tend to be generated. It is desirable to prevent the generation of such aggregates.
In addition, in said preparation, various additives can be mix | blended for the objectives, such as an adhesive force improvement, as long as transparency does not fall. This additive may be added to the aqueous dispersion of the acrylic copolymer of component (a), or at the same time or sequentially when mixing and dispersing the aqueous dispersion of the layered clay mineral. You may do it.
本発明においては、このように調製される水分散型アクリル系粘着剤組成物を、紙、織布、不織布、プラスチックフィルム、金属箔、発泡シート等からなる支持体、あるいは、これらに剥離処理を施した剥離性支持体の片面または両面に、塗布乾燥して、粘着剤層を形成することにより、粘着シートを作製することができる。
この粘着シートは、上記水分散型アクリル系粘着剤組成物の特性に起因して、その粘着剤層が透明性に優れていることを特徴としている。具体的には、粘着剤層の２０μｍ厚での全光線透過率が９０〜１００％、特に好ましくは９２〜１００％であり、またヘイズが０〜２％、特に好ましくは０〜１．５％である。
In the present invention, the water-dispersed acrylic pressure-sensitive adhesive composition prepared as described above is a support made of paper, woven fabric, non-woven fabric, plastic film, metal foil, foamed sheet, or the like, or is subjected to a peeling treatment. A pressure-sensitive adhesive sheet can be produced by coating and drying on one or both sides of the peelable support thus applied to form a pressure-sensitive adhesive layer.
This pressure-sensitive adhesive sheet is characterized in that the pressure-sensitive adhesive layer is excellent in transparency due to the characteristics of the water-dispersed acrylic pressure-sensitive adhesive composition. Specifically, the total light transmittance at 20 μm thickness of the pressure-sensitive adhesive layer is 90 to 100%, particularly preferably 92 to 100%, and haze is 0 to 2%, particularly preferably 0 to 1.5%. It is.
なお、全光線透過率とは、光源より入射した光が、試料を透過する割合のことであり、全光線透過率（％）＝〔（透過光量）／（入射光量）〕×１００で、表される。この全光線透過率が９０％未満では、透過した光が弱くなり透明性が低下する。
また、ヘイズとは、光源より入射した平行光が、試料を透過した際、透過光中の散乱光の割合のことであり、ヘイズ（％）＝〔（透過光中の散乱光）／（全透過光）〕×１００で、表される。このヘイズが２％を超えると散乱光の割合が増加し、白濁して見える傾向にある。
The total light transmittance is a ratio of light incident from the light source to be transmitted through the sample. Total light transmittance (%) = [(transmitted light amount) / (incident light amount)] × 100. Is done. If the total light transmittance is less than 90%, the transmitted light becomes weak and the transparency is lowered.
The haze is the ratio of the scattered light in the transmitted light when the parallel light incident from the light source passes through the sample. Haze (%) = [(scattered light in the transmitted light) / (total Transmitted light)] × 100. When this haze exceeds 2%, the ratio of scattered light increases and it tends to appear cloudy.
つぎに、本発明の実施例を記載して、より具体的に説明する。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。また、層状粘土鉱物の水分散液における層状粘土鉱物の平均粒径とは、ＬＳ１３ ３２０型粒度分布計（ベックマンコールター社）にて平均粒径（ｎｕｍｂｅｒ％）を測定したものである。
Next, examples of the present invention will be described in more detail. In the following, “parts” means parts by weight. The average particle diameter of the layered clay mineral in the aqueous dispersion of the layered clay mineral is obtained by measuring the average particle diameter (number%) with an LS13 320 type particle size distribution meter (Beckman Coulter, Inc.).
冷却管、窒素導入管、温度計および撹拌機を備えた反応容器を用い、アクリル酸ブチル９５部、アクリル酸５部、３−メタクリロイルオキシプロピルトリメトキシシラン（架橋剤）（信越シリコーン社製の「ＫＢＭ−５０３」）０．０５部、２，２′−アゾビス〔２−（５−メチル−２−イミダゾリン−２−イル）プロパン〕ジヒドロクロライド（重合開始剤）０．１部を、ポリオキシエチレンラウリル硫酸ナトリウム（乳化剤）１．５部を添加した水１００部に加えて、乳化重合した。これに１０％アンモニウム水を添加してｐＨ８に調整し、アクリル系共重合体の水分散体を得た。
Using a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer, 95 parts of butyl acrylate, 5 parts of acrylic acid, 3-methacryloyloxypropyltrimethoxysilane (crosslinking agent) (“Shin-Etsu Silicone” KBM-503 ") 0.05 part, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride (polymerization initiator) 0.1 part, polyoxyethylene In addition to 100 parts of water to which 1.5 parts of sodium lauryl sulfate (emulsifier) was added, emulsion polymerization was performed. 10% ammonium water was added thereto to adjust the pH to 8, and an aqueous dispersion of an acrylic copolymer was obtained.
また、イオン交換水９０部にヘキサメタリン酸ナトリウム（キシダ化学社製）０．５部を添加した水溶液に、スメクタイト系層状粘土鉱物（幅方向の理論長５０ｎｍ）をプロピレンオキサイド骨格を有する４級アンモニュウム塩で有機化処理し、層間を１２０モル当量／１００ｇ有機化処理した層状粘土鉱物（コープケミカル社製の「ルーセンタイトＳＰＮ」）１０部を配合し、４８時間浸漬して膨潤させたのち、ホモミキサーにて回転数７，０００ｒｐｍで１５分間分散を行い、層状粘土鉱物の水分散液を調製した。水分散液中の層状粘土鉱物の平均粒径は、１１６ｎｍであった。
A quaternary ammonium salt having a propylene oxide skeleton and a smectite layered clay mineral (theoretical length in the width direction of 50 nm) in an aqueous solution in which 0.5 part of sodium hexametaphosphate (manufactured by Kishida Chemical Co., Ltd.) is added to 90 parts of ion-exchanged water. 10 parts of layered clay mineral (“Lucentite SPN” manufactured by Co-op Chemical Co., Ltd.) whose layers were organically treated at 120 molar equivalents / 100 g were blended and immersed for 48 hours to swell and then homomixer The dispersion was carried out at 7,000 rpm for 15 minutes to prepare an aqueous dispersion of layered clay mineral. The average particle diameter of the layered clay mineral in the aqueous dispersion was 116 nm.
上記のアクリル系共重合体の水分散液２００部に対し、上記の層状粘土鉱物の水分散液１００．５部を加えて、ホモミキサーにて回転数１，０００ｒｐｍで１０分間撹拌混合して、水分散型アクリル系粘着剤組成物を得た。
つぎに、この水分散型アクリル系粘着剤組成物を、シリコーン系剥離剤を塗布した剥離ライナー上に塗布し、１２０℃で３分間加熱乾燥して、粘着剤層の厚さが２０μｍである粘着シートを作製した。
To 200 parts of the above acrylic copolymer aqueous dispersion, add 100.5 parts of the above layered clay mineral aqueous dispersion, and stir and mix with a homomixer at 1,000 rpm for 10 minutes. A water-dispersed acrylic pressure-sensitive adhesive composition was obtained.
Next, this water-dispersed acrylic pressure-sensitive adhesive composition is coated on a release liner coated with a silicone-based release agent, and heated and dried at 120 ° C. for 3 minutes, whereby the pressure-sensitive adhesive layer has a thickness of 20 μm. A sheet was produced.
ヘキサメタリン酸ナトリウムの添加量を１部に変更した以外は、実施例１と同様にして、層状粘土鉱物の水分散液を調製した。水分散液中の層状粘土鉱物の平均粒径は、１１９ｎｍであった。
実施例１で得たアクリル系共重合体の水分散体２００部に対し、上記の層状粘土鉱物の水分散液１０１部を加えた以外は、実施例１と同様にして、水分散型アクリル系粘着剤組成物を得、またこれを用いて、粘着シートを作製した。
A layered clay mineral aqueous dispersion was prepared in the same manner as in Example 1 except that the amount of sodium hexametaphosphate added was changed to 1 part. The average particle size of the layered clay mineral in the aqueous dispersion was 119 nm.
A water-dispersed acrylic system is the same as in Example 1, except that 101 parts of the aqueous dispersion of the layered clay mineral is added to 200 parts of the aqueous dispersion of the acrylic copolymer obtained in Example 1. A pressure-sensitive adhesive composition was obtained, and a pressure-sensitive adhesive sheet was produced using this.
ヘキサメタリン酸ナトリウムの添加量を２部に変更した以外は、実施例１と同様にして、層状粘土鉱物の水分散液を調製した。水分散液中の層状粘土鉱物の平均粒径は、１３２ｎｍであった。
実施例１で得たアクリル系共重合体の水分散体２００部に対し、上記の層状粘土鉱物の水分散液１０２部を加えた以外は、実施例１と同様にして、水分散型アクリル系粘着剤組成物を得、またこれを用いて、粘着シートを作製した。
A layered clay mineral aqueous dispersion was prepared in the same manner as in Example 1 except that the amount of sodium hexametaphosphate added was changed to 2 parts. The average particle size of the layered clay mineral in the aqueous dispersion was 132 nm.
In the same manner as in Example 1, except that 102 parts of the aqueous dispersion of the above layered clay mineral was added to 200 parts of the aqueous dispersion of the acrylic copolymer obtained in Example 1, the water-dispersed acrylic system was used. A pressure-sensitive adhesive composition was obtained, and a pressure-sensitive adhesive sheet was produced using this.
分散剤として、ヘキサメタリン酸ナトリウム０．５部に代えて、ピロリン酸ナトリウム１部を添加した以外は、実施例１と同様にして、層状粘土鉱物の水分散液を調製した。水分散液中の層状粘土鉱物の平均粒径は、１０８ｎｍであった。
実施例１で得たアクリル系共重合体の水分散体２００部に対し、上記の層状粘土鉱物の水分散液１０１部を加えた以外は、実施例１と同様にして、水分散型アクリル系粘着剤組成物を得、またこれを用いて、粘着シートを作製した。
An aqueous dispersion of layered clay mineral was prepared in the same manner as in Example 1 except that 1 part of sodium pyrophosphate was added instead of 0.5 part of sodium hexametaphosphate as a dispersant. The average particle diameter of the layered clay mineral in the aqueous dispersion was 108 nm.
A water-dispersed acrylic system is the same as in Example 1, except that 101 parts of the aqueous dispersion of the layered clay mineral is added to 200 parts of the aqueous dispersion of the acrylic copolymer obtained in Example 1. A pressure-sensitive adhesive composition was obtained, and a pressure-sensitive adhesive sheet was produced using this.
比較例１
ヘキサメタリン酸ナトリウム０．５部を添加しなかった以外は、実施例１と同様にして、層状粘土鉱物の水分散液を調製した。水分散液中の層状粘土鉱物の平均粒径は、１０７ｎｍであった。
実施例１で得たアクリル系共重合体の水分散体２００部に対し、上記の層状粘土鉱物の水分散液１００部を加えた以外は、実施例１と同様にして、水分散型アクリル系粘着剤組成物を得、またこれを用いて、粘着シートを作製した。
Comparative Example 1
An aqueous dispersion of layered clay mineral was prepared in the same manner as in Example 1 except that 0.5 part of sodium hexametaphosphate was not added. The average particle diameter of the layered clay mineral in the aqueous dispersion was 107 nm.
In the same manner as in Example 1, except that 100 parts of the aqueous dispersion of the layered clay mineral was added to 200 parts of the aqueous dispersion of the acrylic copolymer obtained in Example 1, the water-dispersed acrylic type was used. A pressure-sensitive adhesive composition was obtained, and a pressure-sensitive adhesive sheet was produced using this.
比較例２
ヘキサメタリン酸ナトリウムの添加量を７部に変更した以外は、実施例１と同様にして、層状粘土鉱物の水分散液の調製を試みた。しかし、層状粘土鉱物が膨潤せず、水中にうまく分散させることができなかった。このため、水分散型アクリル系粘着剤組成物および粘着シートを得ることができなかった。
Comparative Example 2
Preparation of an aqueous dispersion of layered clay mineral was attempted in the same manner as in Example 1 except that the amount of sodium hexametaphosphate added was changed to 7 parts. However, the layered clay mineral did not swell and could not be dispersed well in water. For this reason, the water-dispersed acrylic pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet could not be obtained.
比較例３
分散剤として、ヘキサメタリン酸ナトリウム０．５部に代えて、スチレンーマレイン酸共重合体の部分エステル化物からなる界面活性剤（荒川化学工業社製の「アラスター７０３Ｓ」）２部を添加した以外は、実施例１と同様にして、層状粘土鉱物の水分散液を調製した。水分散液中の層状粘土鉱物の平均粒径は、１３８ｎｍであった。
実施例１で得たアクリル系共重合体の水分散体２００部に対し、上記の層状粘土鉱物の水分散液１０２部を加えた以外は、実施例１と同様にして、水分散型アクリル系粘着剤組成物を得、またこれを用いて、粘着シートを作製した。
Comparative Example 3
As a dispersant, instead of 0.5 parts of sodium hexametaphosphate, 2 parts of a surfactant ("Alaster 703S" manufactured by Arakawa Chemical Industries) made of a partially esterified product of a styrene-maleic acid copolymer was added. In the same manner as in Example 1, an aqueous dispersion of layered clay mineral was prepared. The average particle size of the layered clay mineral in the aqueous dispersion was 138 nm.
In the same manner as in Example 1, except that 102 parts of the aqueous dispersion of the above layered clay mineral was added to 200 parts of the aqueous dispersion of the acrylic copolymer obtained in Example 1, the water-dispersed acrylic system was used. A pressure-sensitive adhesive composition was obtained, and a pressure-sensitive adhesive sheet was produced using this.
比較例４
ヘキサメタリン酸ナトリウムの添加量を１部に、有機化処理した層状粘土鉱物（コープケミカル社製の「ルーセンタイトＳＰＮ」）の配合量を２５部に、それぞれ変更した以外は、実施例１と同様にして、層状粘土鉱物の水分散液を調製した。水分散液中の層状粘土鉱物の平均粒径は、１２４ｎｍであった。
実施例１で得たアクリル系共重合体の水分散体２００部に対し、上記の層状粘土鉱物の水分散液１１６部を加えた以外は、実施例１と同様にして、水分散型アクリル系粘着剤組成物を得、またこれを用いて、粘着シートを作製した。
Comparative Example 4
Example 1 except that the amount of sodium hexametaphosphate added was changed to 1 part, and the amount of organically treated layered clay mineral (“Lucentite SPN” manufactured by Co-op Chemical) was changed to 25 parts. Then, an aqueous dispersion of layered clay mineral was prepared. The average particle diameter of the layered clay mineral in the aqueous dispersion was 124 nm.
In the same manner as in Example 1, except that 116 parts of the aqueous dispersion of the above layered clay mineral was added to 200 parts of the aqueous dispersion of the acrylic copolymer obtained in Example 1, the water-dispersed acrylic system was used. A pressure-sensitive adhesive composition was obtained, and a pressure-sensitive adhesive sheet was produced using this.
比較例５
ヘキサメタリン酸ナトリウムの添加量を１部に変更し、かつ有機化処理した層状粘土鉱物（コープケミカル社製の「ルーセンタイトＳＰＮ」）１０部に代えて、水酸化マグネシウム（ＪＦＥミネラル社）１０部を配合するようにした以外は、実施例１と同様にして、水酸化マグネシウムの水分散液を調製した。水分散液中の水酸化マグネシウムの平均粒径は、１４６ｎｍであった。
実施例１で得たアクリル系共重合体の水分散体２００部に対し、上記の水酸化マグネシウムの水分散液１０１部を加えた以外は、実施例１と同様にして、水分散型アクリル系粘着剤組成物を得、またこれを用いて、粘着シートを作製した。
Comparative Example 5
The amount of sodium hexametaphosphate added was changed to 1 part, and 10 parts of magnesium hydroxide (JFE Minerals) was replaced with 10 parts of layered clay mineral ("Lucentite SPN" manufactured by Corp Chemical). An aqueous dispersion of magnesium hydroxide was prepared in the same manner as in Example 1 except that it was mixed. The average particle size of magnesium hydroxide in the aqueous dispersion was 146 nm.
In the same manner as in Example 1, except that 101 parts of the aqueous dispersion of magnesium hydroxide was added to 200 parts of the aqueous dispersion of the acrylic copolymer obtained in Example 1, a water-dispersed acrylic system was used. A pressure-sensitive adhesive composition was obtained, and a pressure-sensitive adhesive sheet was produced using this.
比較例６
ヘキサメタリン酸ナトリウムの添加量を１部に変更し、かつ有機化処理した層状粘土鉱物（コープケミカル社製の「ルーセンタイトＳＰＮ」）１０部を配合しなかった以外は、実施例１と同様にして、分散剤の水溶液を調製した。
実施例１で得たアクリル系共重合体の水分散体２００部に対し、上記の分散剤の水溶液９１部を加えた以外は、実施例１と同様にして、水分散型アクリル系粘着剤組成物を得、またこれを用いて、粘着シートを作製した。
Comparative Example 6
Example 1 except that the amount of sodium hexametaphosphate added was changed to 1 part, and 10 parts of organically treated layered clay mineral (“Lucentite SPN” manufactured by Corp Chemical Co.) was not blended. An aqueous solution of the dispersant was prepared.
A water-dispersed acrylic pressure-sensitive adhesive composition in the same manner as in Example 1, except that 91 parts of the aqueous solution of the above-described dispersant was added to 200 parts of the aqueous dispersion of the acrylic copolymer obtained in Example 1. A pressure-sensitive adhesive sheet was prepared using this product.
上記の実施例１〜４および比較例１，３〜６の各サンプルについて、以下の方法にて、凝集物の発生割合、ヘイズ、全光線透過率、弾性率、耐熱保持性の試験を行った。これらの測定結果は、表１に示されるとおりであった。
なお、ヘイズ、全光線透過率、弾性率の測定を行った粘着シートの厚さは２０μｍで、測定雰囲気は２３℃、４５％ＲＨで行った。
About each sample of said Examples 1-4 and Comparative Examples 1, 3-6, the test of the generation | occurrence | production ratio of an aggregate, a haze, a total light transmittance, an elastic modulus, and heat resistance retention property was done with the following method. . These measurement results were as shown in Table 1.
In addition, the thickness of the adhesive sheet which measured the haze, the total light transmittance, and the elasticity modulus was 20 micrometers, and measurement atmosphere was 23 degreeC and 45% RH.
＜凝集物の発生割合＞
水分散型アクリル系粘着剤組成物を、＃８０ナイロンメッシュでフィルタリングを行い、メッシュ上に残った固形分を秤量し、疑集物の発生割合を下記の式より求めた。
〔凝集物の発生割合〕（％）＝（メッシュ上の固形分）ｇ／（理論固形分総量）ｇ
×１００
<Occurrence rate of aggregate>
The water-dispersed acrylic pressure-sensitive adhesive composition was filtered with a # 80 nylon mesh, the solid content remaining on the mesh was weighed, and the occurrence rate of suspected substances was determined from the following formula.
[Occurrence ratio of agglomerates] (%) = (solid content on mesh) g / (total theoretical solid content) g
× 100
＜ヘイズ、全光線透過率＞
粘着シートを、スライドガラス（ＭＩＣＲＯ ＳＬＩＤＥ ＧＬＡＳＳ Ｓ−１２１４、７６mm×２６mm×１．３mm、ＭＡＴＳＵＮＡＭＩ社製）に貼り合わせる。剥離ライナーを取り除いたのち、フィルム濁度計（日本電色工業社の「ＮＤＭ−２０Ｄ」）を用いて、ヘイズ、全光線透過率の測定を行った。
<Haze, total light transmittance>
The pressure-sensitive adhesive sheet is bonded to a slide glass (MICRO SLIDE GLASS S-1214, 76 mm × 26 mm × 1.3 mm, manufactured by MATSUNAMI). After removing the release liner, haze and total light transmittance were measured using a film turbidimeter (“NDM-20D” manufactured by Nippon Denshoku Industries Co., Ltd.).
＜弾性率＞
粘着シートを３mm角に切り出し、塗工の幅方向に丸めたものを使用した。つかみの間隔を１０mmにし、引張り速度は５０mm／分にし、引張り試験機ＴＧ−１ＫＮ（ミネベア社）にて、応力−歪試験を行い、その初期傾きから、弾性率を求めた。
<Elastic modulus>
A pressure-sensitive adhesive sheet was cut into a 3 mm square and rounded in the width direction of the coating. The distance between the grips was set to 10 mm, the pulling speed was set to 50 mm / min, and a stress-strain test was performed with a tensile tester TG-1KN (Minebea), and the elastic modulus was obtained from the initial inclination.
＜耐熱保持性＞
７０mm×２５mm×０．４mmのアルミ板に、１５mm×１５mmに切り出した厚さ２０μｍの粘着シートを貼り合わせる。同サイズのアルミ板を、５kgロールで１往復して圧着して、貼り合わせたのち、２３℃の雰囲気で２４時間放置後、各雰囲気温度でせん断方向に２kgの荷重を加え、２時間保持可能な最高温度を調べた。
<Heat resistance retention>
An adhesive sheet having a thickness of 20 μm cut into 15 mm × 15 mm is bonded to an aluminum plate of 70 mm × 25 mm × 0.4 mm. After the aluminum plate of the same size is reciprocated once with a 5kg roll, and bonded together, it is allowed to stand for 24 hours in an atmosphere at 23 ° C. The highest temperature was investigated.
表１
┌────┬──────┬────┬──────┬──────┬─────┐
│ │凝集物の発生│ヘイズ │全光線透過率│ 弾性率 │耐熱保持性│
│ │ （％） │ （％）│ （％） │（Ｎ／mm2 ）│ （℃） │
├────┼──────┼────┼──────┼──────┼─────┤
│ │ │ │ │ │ │
│実施例１│ ０ │ ０．８│ ９２．３ │ ５５．６ │ １８０ │
│ │ │ │ │ │ │
│実施例２│ ０ │ １．１│ ９２．４ │ ９０．０ │ １８０ │
│ │ │ │ │ │ │
│実施例３│ ０ │ １．２│ ９２．２ │ ４０．０ │ １８０ │
│ │ │ │ │ │ │
│実施例４│ ０ │ ０．９│ ９２．９ │ ８３．３ │ １８０ │
│ │ │ │ │ │ │
├────┼──────┼────┼──────┼──────┼─────┤
│ │ │ │ │ │ │
│比較例１│ ５ │ ５．１│ ９１．３ │ １３．３ │ １８０ │
│ │ │ │ │ │ │
│比較例３│ ０ │ ４．１│ ９１．８ │ ５０．０ │ １８０ │
│ │ │ │ │ │ │
│比較例４│ ０ │ ２．２│ ９１．５ │ ８３．３ │ ２００ │
│ │ │ │ │ │ │
│比較例５│ ０ │６５．２│ ９１．０ │ ６２．５ │ １００ │
│ │ │ │ │ │ │
│比較例６│ ０ │ ０．７│ ９２．４ │ １６．８ │ ８０ │
│ │ │ │ │ │ │
└────┴──────┴────┴──────┴──────┴─────┘
Table 1
┌────┬──────┬────┬──────┬──────┬─────┐
│ │ Aggregate generation │ Haze │ Total light transmittance │ Elastic modulus │ Heat resistance │
│ │ (%) │ (%) │ (%) │ (N / mm 2 ) │ (℃) │
├────┼──────┼────┼──────┼──────┼─────┤
│ │ │ │ │ │ │
│Example 1 │ 0 │ 0.8│ 92.3 │ 55.6 │ 180 │
│ │ │ │ │ │ │
│Example 2│ 0 │ 1.1│ 92.4 │ 90.0 │ 180 │
│ │ │ │ │ │ │
│Example 3│ 0 │ 1.2│ 92.2 │ 40.0 │ 180 │
│ │ │ │ │ │ │
Example 4 | 0 | 0.9 | 92.9 | 83.3 | 180 |
│ │ │ │ │ │ │
├────┼──────┼────┼──────┼──────┼─────┤
│ │ │ │ │ │ │
│Comparative Example 1│ 5 │ 5.1│ 91.3 │ 13.3 │ 180 │
│ │ │ │ │ │ │
│Comparative Example 3│ 0 │ 4.1│ 91.8 │ 50.0 │ 180 │
│ │ │ │ │ │ │
│Comparative Example 4│ 0 │ 2.2│ 91.5 │ 83.3 │ 200 │
│ │ │ │ │ │ │
│Comparative Example 5│ 0 │65.2│ 91.0 │ 62.5 │ 100 │
│ │ │ │ │ │ │
│Comparative Example 6│ 0 │ 0.7│ 92.4 │ 16.8 │ 80 │
│ │ │ │ │ │ │
└────┴──────┴────┴──────┴──────┴─────┘
上記の表１の結果から明らかなように、本発明の実施例１〜４の水分散型アクリル系粘着剤組成物は、凝集物の発生がみられず、これより得られる粘着シートは、ヘイズが２％以下、全光線透過率が９０％以上で、透明性に優れており、また弾性率が高くて高凝集力を示し、さらに耐熱保持性にも優れていることがわかる。
これに対し、比較例１，３〜６では、水分散型アクリル系粘着剤組成物に凝集物がみられたり、粘着シートの透明性に劣るか、あるいは凝集力が低いか、耐熱保持性に劣る等の欠点があり、上記の各特性をすべて満足させることができなかった。
As is clear from the results in Table 1 above, the water-dispersed acrylic pressure-sensitive adhesive compositions of Examples 1 to 4 of the present invention showed no occurrence of aggregates, and the pressure-sensitive adhesive sheet obtained therefrom had a haze. Is 2% or less, the total light transmittance is 90% or more, it is excellent in transparency, it has a high elastic modulus and exhibits a high cohesive force, and is also excellent in heat resistance retention.
On the other hand, in Comparative Examples 1 and 3-6, the water-dispersed acrylic pressure-sensitive adhesive composition has aggregates, the pressure-sensitive adhesive sheet is inferior in transparency, or the cohesive force is low. There were drawbacks such as inferiority, and all of the above characteristics could not be satisfied.
Claims (6)
(A) an acrylic copolymer of 90 to 99% by weight of a vinyl monomer and 10 to 1% by weight of a polar group-containing monomer, the main component of which is a (meth) acrylic acid alkyl ester of an alkyl alcohol having 4 to 14 carbon atoms. (B) 1 to 20 parts by weight of a layered clay mineral treated with an organic cation having a hydrophilic functional group per 100 parts by weight of the acrylic copolymer is (c) phosphoric acid. In the method for producing a water-dispersed acrylic pressure-sensitive adhesive composition that is dispersed in the presence of 0.1 to 5 parts by weight of a system dispersant, the component (b) is added to the aqueous solution of the phosphoric acid dispersant as the component (c). A layered clay mineral that has been organically treated with an organic cation having a hydrophilic functional group is added and dispersed, and this dispersion is added to the aqueous dispersion of the acrylic copolymer of component (a) and mixed and dispersed. Water dispersion type a Method for producing a drill-based adhesive composition.
(B) a layered clay mineral which has been organically treated with an organic cation having a hydrophilic functional group of the component, method for producing a water-dispersible accession Li Le-based pressure-sensitive adhesive composition according to claim 1 which is smectite.
The method for producing a water-dispersed acrylic pressure-sensitive adhesive composition according to claim 1 or 2 , wherein the organic cation having a hydrophilic functional group in component (b) is a hydroxyl group-containing quaternary ammonium salt.
The method for producing a water-dispersed acrylic pressure-sensitive adhesive composition according to any one of claims 1 to 3 , wherein the phosphoric acid-based dispersant of component (c) is sodium hexametaphosphate.
A pressure-sensitive adhesive having a pressure-sensitive adhesive layer on which a water-dispersed acrylic pressure-sensitive adhesive composition produced by the method according to any one of claims 1 to 4 is applied and dried on a support or a peelable support. Sheet.
The pressure-sensitive adhesive sheet according to claim 5 , wherein the pressure-sensitive adhesive layer has a total light transmittance of 90 to 100% and a haze of 0 to 2% at a thickness of 20 μm.
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| JPH10168182A (en) * | 1996-12-09 | 1998-06-23 | Agency Of Ind Science & Technol | Dispersion and its production |
| JPH1171477A (en) * | 1997-04-30 | 1999-03-16 | J M Huber Corp | Surface-treated clay product, production and use thereof, and product obtained therefrom |
| JP2002294209A (en) * | 2001-03-30 | 2002-10-09 | Sekisui Chem Co Ltd | Pressure-sensitive adhesive composition, process for preparation thereof, and pressure-sensitive adhesive tape |
| JP2002363522A (en) * | 2001-06-06 | 2002-12-18 | Nitto Denko Corp | Clear pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet thereof |
| JP2003140559A (en) * | 2001-11-07 | 2003-05-16 | Nitto Denko Corp | Filmlike filter for preventing glass breakage and plasma display device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10168182A (en) * | 1996-12-09 | 1998-06-23 | Agency Of Ind Science & Technol | Dispersion and its production |
| JPH1171477A (en) * | 1997-04-30 | 1999-03-16 | J M Huber Corp | Surface-treated clay product, production and use thereof, and product obtained therefrom |
| JP2004509986A (en) * | 2000-09-21 | 2004-04-02 | ローム アンド ハース カンパニー | Modified nanocomposite compositions and methods of making and using the same |
| JP2002294209A (en) * | 2001-03-30 | 2002-10-09 | Sekisui Chem Co Ltd | Pressure-sensitive adhesive composition, process for preparation thereof, and pressure-sensitive adhesive tape |
| JP2002363522A (en) * | 2001-06-06 | 2002-12-18 | Nitto Denko Corp | Clear pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet thereof |
| JP2003140559A (en) * | 2001-11-07 | 2003-05-16 | Nitto Denko Corp | Filmlike filter for preventing glass breakage and plasma display device |
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