A chemically-resistant multi-layered electro-optic device and a method of making the same

Abstract

This invention relates to a chemically resistant electro-optic device and its manufacturing method. The device comprises a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer comprising a conductive polymer, a first adhesive layer, and a second substrate layer comprising a thermoplastic resin. The first adhesive layer comprises polyurethane and polyvinyl alcohol, wherein the polyvinyl alcohol contains acetylacetyl acetate functional groups in its molecular structure.

Description

Technical Field

[0001] [Related Applications] This application claims priority to U.S. Provisional Patent Application No. 63 / 653,626, filed May 30, 2024, which, along with all other patents and patent applications disclosed herein, is incorporated herein by reference in its entirety. [Technology of Inventions]

[0002] This invention relates to a chemical-resistant, water-resistant, multilayer electro-optic device and its manufacturing method. The chemical-resistant and water-resistant multilayer electro-optic device comprises: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, a first adhesive layer, and a second substrate layer. The first adhesive layer comprises a polyurethane or acrylic polymer and cross-linked polyvinyl alcohol, wherein the polyvinyl alcohol contains acetylacetonate functional groups in its molecular structure. Prior Technology

[0003] The term "electro-optic," used in this paper in relation to materials or displays, refers to a material having first and second display states, where at least one optical property differs, and the material is switched from its first display state to its second display state by applying an electric field. While this optical property is typically color perceptible to the human eye, it can also be other optical properties such as optical transmission, reflection, emission, or, in the case of a machine-readable display, pseudo-color in the sense of a change in reflection of electromagnetic wavelengths outside the visible light range.

[0004] The terms "bistable" and "bistability" are used herein in their conventional sense to refer to a display comprising display elements having first and second display states that differ in at least one optical property, and that after any given element is driven by a finite-duration addressing pulse to acquire its first or second display state, that state remains for at least several times (e.g., at least four times) the minimum duration of the addressing pulse required to change the state of the display element. U.S. Patent No. 7,170,670 indicates that some particle-based electrophoretic displays with grayscale functionality are stable not only in their extreme black and white states but also in the intermediate gray state, and the same is true for some other types of electro-optical displays. Although for convenience, the term "bistable" may be used herein to encompass both bistable and multistable displays, this type of display is more appropriately referred to as "multistable" than "bistable."

[0005] An electro-optical device that has been the subject of in-depth research and development for many years, it is a particle-based electrophoretic display in which multiple charged particles move through a fluid under the influence of an electric field. Compared with liquid crystal displays, electrophoretic displays can have properties such as good brightness and contrast, wide viewing angle, dual stability, and low power consumption.

[0006] Numerous patents and applications, assigned to or published in the name of MIT, E Ink, E Ink California, LLC, and related companies, describe various techniques used in encapsulation and microcellular electrophoresis and other electro-optic media. Encapsulated electrophoresis media comprise a plurality of microcapsules, each containing: an inner phase containing electrophoretically moving particles in a fluid medium; and a capsule wall surrounding the inner phase. Typically, these capsules are themselves housed within a polymeric adhesive to form a coherent layer disposed between two electrodes. In microcellular electrophoresis displays, the charged particles and the fluid are not encapsulated within microcapsules but are instead retained in a plurality of cavities formed within a carrier medium, typically a polymer membrane.

[0007] The technologies described in these patents and applications include: (a) Electrophoretic particles, fluids, and fluid additives; see, for example: U.S. Patent Nos. 5,961,804; 6,017,584; 6,120,588; 6,120,839; 6,262,706; 6,262,833; 6,300,932; 6,323,989; 6,377,387; 6,515,649; 6,538,801; 6,580,545; 6,652,075; 6,693,620; 6,721,083; 6,727,881; 6,822,782; 6,831,771; 6,870,661; 6,927,892; 6,956,690; 6,958,849; 7 002,728;7,038,655;7,052,766;7,110,162;7,113,323;7,141,688;7,142,351;7,170,670;7,226,550;7,230,750;7,230,751;7,236,290;7,277,2 18;7,286,279;7,312,916;7,382,514;7,390,901;7,473,782;7,561,324;7,583,251;7,572,394;7,576,904;7,580,180;7,679,814;7,848,006;7, 903,319;8,018,640;8,115,729;8,257,614;8,270,064;8,363,306;8,390,918;8,582,196;8,654,436;8,902,491;8,961,831;9,052,564;9,341, 915;9,348,193;9,361,836;9,366,935;9,372,380;9,382,427;9,423,666;9,428,649;9,557,623;9,670,367;9,671,667;9,688,859;9,726,957;9 ,752,034;9,765,015;9,778,535;9,778,537;9,835,926;9,953,588;9,995,987;10,025,157;10,031,394;10,040,954;10,061,123;10,062,337;1 0,147,366; and 10,514,583; and U.S. Patent Application Publications 2003 / 0048522; 2003 / 0151029; 2003 / 0164480; 2004 / 0030125; 2004 / 0105036; 2005 / 0012980; 2009 / 0009852;2011 / 0217639; 2012 / 0049125; 2013 / 0161565; 2013 / 0193385; 2013 / 0244149; 2013 / 0063333; 2014 / 0011913; 2014 / 0078576; 2014 / 0104674; 2014 / 0231728; 2015 / 0177590; 2015 / 0185509; 2015 / 0241754; 2015 / 0301425; and 2016 / 0170106; (b) Capsules, adhesives, and encapsulation methods; see, for example: U.S. Patents 5,930,026; 6,067,185; 6,130,774; 6,262,706; 6,327,072; 6,392,786; 6,459,418; 6,727,881; 6,839,158; 6,866,760; 6,922,276; 6,958,848; 6,987,603; 7,110,164; 7,148,128; 7,184,197; 7,304,634; 7,327,511, U.S. Patent Application Publications Nos. 7,339,715, 7,411,719, 7,477,444, 7,561,324, 7,910,175, 7,952,790, 8,129,655, 8,446,664; and U.S. Patent Application Publications Nos. 2005 / 0156340, 2007 / 0091417, and 2009 / 0122389; (c) Microcellular structures, wall materials, and methods for forming microcells; see, for example: U.S. Patents 6,672,921; 6,751,007; 6,753,067; 6,781,745; 6,788,452; 6,795,229; 6,806,995; 6,829,078; 6,850,355; 6,865,012; 6,870,66 2;6,885,495;6,930,818;6,933,098;6,947,202;7,046,228;7,072,095;7,079,303;7,141,279;7,156,945;7,205,355;7,233,429;7,261,920;7,271,947;7,304,7 80;7,307,778;7,327,346;7,347,957;7,470,386;7,504,050;7,580,180;7,715,087;7,767,126;7,880,958;8,002,948;8,154,790;8,169,690;8,441,432;8,891, 156; 9,279,906; 9,291,872; 9,388,307; 9,436,057; 9,436,058; 9,470,917; 9,919,553; and 10,401,668; and U.S. Patent Application Publication Nos. 2003 / 0203101; 2014 / 0050814; and 2016 / 0059442; (d) A method for filling and sealing microcells; see, for example: U.S. Patents 6,545,797; 6,788,449; 6,831,770; 6,833,943; 6,930,818; 7,046,228; 7,052,571; 7,166,182; 7,347,957; 7,374,634; 7,385,751; 7,408,696; 7,557,981; 7,560,004; 7,564,614; 7,572,491; 7,616,374; 7,715,087; 7,715,088; 8,361,356; 8,625,188; 8,830,561; 9,346,987; and 9,759,978; and U.S. Patent Application Publication Nos. 2002 / 0188053; 2004 / 0120024; 2004 / 0219306; and 2015 / 0098124; (e) Films and subassemblies containing electro-optic materials; see, for example: U.S. Patents 6,825,829; 6,982,178; 7,110,164; 7,158,282; 7,554,712; 7,561,324; 7,649,666; 7,728,811; 7,826,129; 7,839,564; 7,843,62 1; 7,843,624; 7,952,790; 8,034,209; 8,177,942; 8,390,301; 9,238,340; 9,470,950; 9,835,925; and U.S. Patent Application Publication Nos. 2005 / 0122563; 2007 / 0237962; and 2011 / 0164301; (f) Backplates, adhesive layers, and other auxiliary layers and methods used in displays; see, for example: U.S. Patent Nos. D485,294; 5,930,026; 6,120,588; 6,124,851; 6,177,921; 6,232,950; 6,252,564; 6,312,304; 6,312,971; 6,376,828; 6,392,786; 6,413,790; 6,480,182; 6,498,114; 6,506,438; 6,518,949; 6,545,291; 6,639,578; 6,657,772; 6,664,944; 6,683,333; 6,7 10,540;6,724,519;6,816,147;6,819,471;6,825,068;6,831,769;6,842,279;6,842,657;6,865,010;6,873,452;6,909,532;6,967,640;7,012,60 0;7,012,735;7,030,412;7,075,703;7,106,296;7,110,163;7,116,318;7,148,128;7,167,155;7,173,752;7,176,880;7,190,008;7,206,119;7,2 23,672;7,230,751;7,256,766;7,259,744;7,301,693;7,304,780;7,327,346;7,327,511;7,347,957;7,365,733;7,388,572;7,401,758;7,492,4 97;7,535,624;7,551,346;7,554,712;7,560,004;7,583,427;7,649,674;7,667,886;7,672,040;7,688,497;7,826,129;7,830,592;7,839,564;7, 880,958;7,893,435;7,905,977;7,952,790;7,986,450;8,034,209;8,049,947;8,072,675;8,120,836;8,159,636;8,177,942;8,237,892;8,362,4 88;8,395,836;8,437,069;8,441,414;8,456,589;8,514,168;8,547,628;8,576,162;8,610,988;8,714,780;8,743,077;8,754,85​​9;8,797,258;8,797,633;8,797,636;9,147,364;9,025,234;9,025,238;9,030,374;9,140,​​952;9,201,279;9,223,164;9,238,340;9,285,648;9,454,057;9,529,240;9,620,066;9 ,632,373;9,666,142;9,671,635;9,715,155;9,777,201;9,897,891;10,037,735;10,190,743;10,324,577;10,365,533;10,372,008;10,446,585;10,466,565;10,495,9 41;10,503,041;10,509,294;10,613,407; and U.S. Patent Application Publication Nos. 2002 / 0060321; 2004 / 0085619; 2004 / 0105036; 2005 / 0122306; 2005 / 0122563; 2006 / 0255322; 2009 / 0122389; 2010 Patent applications Nos. 0177396, 2011 / 0164301, 2011 / 0292319, 2014 / 0192000, 2014 / 0210701, 2014 / 0368753, and 2016 / 0077375; and International Patent Application Publications Nos. WO2000 / 038000, WO2000 / 005704, and WO1999 / 067678; (g) Color formation and color adjustment; see, for example: U.S. Patents 6,017,584; 6,545,797; 6,664,944; 6,788,452; 6,864,875; 6,914,714; 6,972,893; 7,038,656; 7,038,670; 7,046,228; 7,052,571; 7,075,502; 7,167,155; 7,385,751; 7,492,505; 7,667,684; 7,684,108; 7,791,789; 7,800,813; 7,821,702; 7,839,564; 7,910,175; 7,952, 790;7,956,841;7,982,941;8,040,594;8,054,526;8,098,418;8,159,636;8,213,076;8,363,299;8,422,116;8,441,714;8,441,716;8,466,852; 8,503,063;8,576,470;8,576,475;8,593,721;8,605,354;8,649,084;8,670,174;8,704,756;8,717,664;8,786,935;8,797,634;8,810,899;8,830 ,559;8,873,129;8,902,153;8,902,491;8,917,439;8,964,282;9,013,783;9,116,412;9,146,439;9,164,207;9,170,467;9,170,468;9,182,646;9,195,111;9,199,441;9,268,191;9,285,649;9,293,511;9,341,916;9,360,733;9,361,836;9,383,623; and9,423,666; and U.S. Patent Application Publication No. 2008 / 004331 8;2008 / 0048970;2009 / 0225398;2010 / 0156780;2011 / 0043543;2012 / 0326957;2013 / 0242378;2013 / 0278995;2014 / 0055840;2014 / 0078576;2014 / 0340430;2014 / 0340736;2014 / 0362213;2015 / 0103394;2015 / 0118390;2015 / 0124345;2015 / 0198858;2015 / 0234250;2015 / 0268531;2015 / 0301246;2016 / 0011484; 2016 / 0026062; 2016 / 0048054; 2016 / 0116816; 2016 / 0116818; and 2016 / 0140909; (h) A method for driving a display; see, for example: U.S. Patent Nos. 5,930,026; 6,445,489; 6,504,524; 6,512,354; 6,531,997; 6,753,999; 6,825,970; 6,900,851; 6,995,550; 7,012,600; 7,023,420; 7,034,783; 7,061,166; 7,061,662; 7,116,466; 7,119,772; 7,177,066; 7,193,625; 7,202,847; 7,242,514; 7,259,744; 7,304,787; 7, 312,794;7,327,511;7,408,699;7,453,445;7,492,339;7,528,822;7,545,358;7,583,251;7,602,374;7,612,760;7,679,599;7,679,813;7,683 ,606;7,688,297;7,729,039;7,733,311;7,733,335;7,787,169;7,859,742;7,952,557;7,956,841;7,982,479;7,999,787;8,077,141;8,125,501 ;8,139,050;8,174,490;8,243,013;8,274,472;8,289,250;8,300,006;8,305,341;8,314,784;8,373,649;8,384,658;8,456,414;8,462,102;8, 514,168;8,537,105;8,558,783;8,558,785;8,558,786;8,558,855;8,576,164;8,576,259;8,593,396;8,605,032;8,643,595;8,665,206;8,681 ,191;8,730,153;8,810,525;8,928,562;8,928,641;8,976,444;9,013,394;9,019,197;9,019,198;9,019,318;9,082,352;9,171,508;9,218,77 3;9,224,338;9,224,342;9,224,344;9,230,492;9,251,736;9,262,973;9,269,311;9,299,294;9,373,289;9,390,066;9,390,661; and 9,412,314;and U.S. Patent Application Publications Nos. 2003 / 0102858; 2004 / 0246562; 2005 / 0253777; 2007 / 0091418; 2007 / 0103427; 2007 / 0176912; 2008 / 0024429; 2008 / 0024482; 2008 / 0136774; 2008 / 0291129; 2008 / 0303780; 2009 / 0174651; 2009 / 0195568; 20 09 / 0322721;2010 / 0194733;2010 / 0194789;2010 / 0220121;2010 / 0265561;2010 / 0283804;2011 / 0063314;2011 / 0175875;2011 / 0193840;2011 / 0193841;2011 / 0199671;2011 / 0221740;2012 / 0001957;2012 / 0098740;20 13 / 0063333;2013 / 0194250;2013 / 0249782;2013 / 0321278;2014 / 0009817;2014 / 0085355;2014 / 0204012;2014 / 0218277;2014 / 0240210;2014 / 0240373;2014 / 0253425;2014 / 0292830;2014 / 0293398;2014 / 0333685;20 14 / 0340734; 2015 / 0070744; 2015 / 0097877; 2015 / 0109283; 2015 / 0213749; 2015 / 0213765; 2015 / 0221257; 2015 / 0262255; 2015 / 0262551; 2016 / 0071465; 2016 / 0078820; 2016 / 0093253; 2016 / 0140910; and 2016 / 0180777; (i) Applications of displays; see, for example: U.S. Patent Nos. 6,118,426; 6,473,072; 6,704,133; 6,710,540; 6,738,050; 6,825,829; 7,030,854; 7,119,759; 7,312,784; 7,705,824; 8,009,348; 8,011,592; 8,064,962; 8,162,212; 8,553,012; 8,973,837; 9,188,829; and 9,197,704; and U.S. Patent Application Publications 2002 / 0090980; 2004 / 0119681; 2007 / 0285385; 2013 / 0176288; 2013 / 0221112; 2013 / 0233930; 2013 / 0235536; 2014 / 0049808; 2014 / 0062391; 2014 / 0206292; and 2016 / 0035291; and International Patent Application Publication WO00 / 36560; and (j) Non-electrophoretic displays; see, for example, U.S. Patents 6,241,921; 6,784,953; 6,795,138; 6,914,713; 6,950,220; 7,095,477; 7,182,830; 7,245,414; 7,420,549; 7,471,369; 7,576,904; 7,580,180; 7,850,867; 8,018,643; 8,023,071; 8,282,762; 8,319,759; And U.S. Patent Application Publications Nos. 8,994,705 and 2005 / 0099575, 2006 / 0262249, 2007 / 0042135, 2007 / 0153360, 2008 / 0020007, 2012 / 0293858, and 2015 / 0277160; and encapsulation and microcellular applications other than displays; see, for example, U.S. Patent No. 7,615,325; and U.S. Patent Application Publications Nos. 2015 / 0005720 and 2016 / 0012710.

[0008] Although electrophoretic media are typically opaque (because, for example, in many electrophoretic media, the particles substantially block visible light from passing through the display) and operate in a reflective mode, many electrophoretic displays can be made to operate in a so-called "shutter mode," where one display state is substantially opaque and the other is transparent. See, for example, U.S. Patents 5,872,552; 6,130,774; 6,144,361; 6,172,798; 6,271,823; 6,225,971 and 6,184,856. Dual electrophoretic displays, similar to electrophoretic displays but relying on changes in electric field strength, can operate in a similar mode; see U.S. Patent 4,418,346. Other types of electro-optic displays can also operate in a shutter mode. Electro-optic media operating in shutter mode can be used in multi-layer structures for full-color displays; in such structures, at least one layer adjacent to the viewing surface of the display operates in shutter mode to expose or hide a second layer that is farther from the viewing surface.

[0009] The manufacture of three-layer electrophoretic displays typically involves at least one lamination operation. For example, many of the aforementioned MIT and E Ink patents and applications describe a process for manufacturing encapsulated electrophoretic displays, in which an encapsulated electrophoretic medium containing capsules in an adhesive is coated onto a flexible substrate layer on a plastic film containing an indium tin oxide (ITO) or similar conductive coating (serving as one of the electrodes in the final display). The capsule / adhesive coating is then dried to form a robust electrophoretic medium adhesive layer firmly bonded to the substrate layer. A backplane containing a pixel electrode array and a suitable conductor arrangement connecting the pixel electrodes to drive circuitry is prepared separately. To form the final display, the substrate layer with the capsule / adhesive layer is laminated to the backplane using a laminating adhesive. In a preferred form of this process, the backplane is flexible and is prepared by printing the pixel electrodes and conductors onto a plastic film or other flexible substrate layer. An obvious lamination technique for mass-producing displays using this process is roll lamination using a laminating adhesive.

[0010] Electrophoretic displays typically comprise an electro-optic material layer and at least two other layers disposed on opposite sides of the electrophoretic material, one of which is an electrode layer. In such displays, most are electrode layers, and one or both of these electrode layers are patterned to define pixels of the display. For example, one electrode layer may be patterned as an extended column electrode and the other as an extended row electrode orthogonal to the column electrode, with the intersection of the column and row electrodes defining the pixel. Or more commonly, one electrode layer has a single continuous electrode configuration, and the other electrode layer is patterned as a matrix of pixel electrodes, each pixel electrode defining a pixel of the display. In another type of electrophoretic display intended for use with probes, printheads, or similar movable electrodes separate from the display, only the layer adjacent to the electro-optic material layer contains electrodes, and the layer on the opposite side of the electro-optic material layer is typically a protective layer intended to prevent the movable electrode from damaging the electro-optic material layer.

[0011] Fabricating a three-layer optoelectronic display typically involves at least one lamination operation. For example, many of the aforementioned MIT and E Ink patents and applications describe a process for manufacturing an encapsulated electrophoretic display, in which an encapsulated electrophoretic medium containing capsules in an adhesive is coated onto a flexible substrate layer containing indium tin oxide (ITO) or a similar conductive coating on a plastic film. A backplane containing a pixel electrode array and a suitable arrangement of conductors connecting the pixel electrodes to drive circuitry is fabricated separately. To form the final display, a laminating adhesive is used to laminate the substrate layer with the electro-optic material layer onto the backplane.

[0012] The aforementioned U.S. Patent No. 6,982,178 describes a method for assembling a solid-state electro-optic display, which is well-suited for mass production. Essentially, this patent describes a so-called "front-plane laminate" ("FPL") that sequentially comprises: a light-transmitting electrode layer; an electro-optic material layer electrically in contact with the light-transmitting electrode layer; an adhesive layer; and a release sheet. Typically, the light-transmitting electrode layer is supported on a light-transmitting substrate layer, which is preferably flexible, in that the substrate can be manually wound onto a roller with a diameter of, for example, 10 inches (254 mm) without permanent deformation. The substrate layer is typically a polymer film and generally has a thickness of about 1 to about 25 mils (25 to 634 μm), preferably about 2 to about 10 mils (51 to 254 μm). For convenience, the light-transmitting electrode layer is a thin metal or metal oxide layer, such as aluminum or ITO, or it may be a conductive polymer. Poly(ethylene terephthalate) (PET) films coated with aluminum or ITO are commercially available, for example, "Aluminized Mylar" ("Mylar" is a registered trademark) from EI du Pont de Nemours & Company, Wilmington DE. Such commercial materials can be used in front-plane laminates with good results. Assembly of electrophoretic displays using such front-plane laminates can be achieved by removing the release sheet from the front-plane laminate and bringing the adhesive layer into contact with the backplate under conditions that effectively adhere the adhesive layer to the backplate, thereby fixing the adhesive layer, electro-optic material layer, and light-transmitting electrode layer to the backplate. This process is well-suited for mass production because front-plane laminates can be mass-produced (typically using roll-to-roll coating technology) and then cut into segments of any size required for use with a specific backplate.

[0013] U.S. Patent No. 7,561,324 describes a so-called "dual release sheet," which is essentially a simplified version of the front-plane laminate of the aforementioned U.S. Patent No. 6,982,178. One form of dual release sheet comprises an electro-optic material layer sandwiched between two adhesive layers, wherein one or both of the adhesive layers are covered by the release sheet. Another form of dual release sheet comprises a layer of solid electro-optic material sandwiched between two release sheets. Both forms of dual release sheets are intended for use in a process substantially similar to that of assembling an electrophoretic display from the already described front-plane laminate, but involving two separate laminations; typically, in the first lamination, the dual release sheet is laminated to the front electrode to form a front sub-assembly, and then in the second lamination, the front sub-assembly is laminated to the backplane to form the final display, but the order of these two laminations can be reversed if desired.

[0014] U.S. Patent No. 7,839,564 describes a so-called "inverted front planar laminate," a variation of the front planar laminate described in U.S. Patent No. 6,982,178. This inverted front planar laminate may sequentially include: at least one of a light-transmitting protective layer and a light-transmitting electrode layer; an adhesive layer; an electro-optic material layer; and a release liner. This inverted front planar laminate is used to form an electro-optic device having a laminated adhesive layer between the electro-optic material layer and the light-transmitting electrode layer; a second adhesive layer, typically thin, may or may not be present between the electro-optic material layer and the backplate. Such an electro-optic display can combine good resolution with good low-temperature performance.

[0015] All the above references are incorporated into this paper in their entirety by way of citation.

[0016] Electro-optic devices, including those incorporating electrophoretic media, can be used in a wide range of applications, such as e-readers, electronic notebooks, self-adhesive labels, outdoor signs, variable transmittance windows, automotive surfaces, safety markings, security labels, and authentication films. Some applications require devices to be resilient to operate under a variety of conditions and resistant to a variety of chemicals. These conditions may include exposure to moisture, exposure to other chemicals such as organic solvents, or even immersion of the device in such solvents.

[0017] Employing flexible and cost-effective processes is crucial for manufacturing electro-optic devices. The optimal process involves manufacturing encapsulated electrophoretic media in a factory and then manufacturing the electro-optic device at a later time in a different factory. This is necessary because of the complex properties of encapsulated electrophoretic media, and different entities will use encapsulated electrophoretic media for various applications. Intermediate electro-optic laminates, such as FPL, reverse FPL, and others, enable this. For example, FPL can be manufactured in a factory, stored in a warehouse, and transported to another factory for device conversion after additional layers are attached. Typically, the conversion process involves removing one or more release layers from the intermediate electro-optic laminate, exposing the adhesive layer, and attaching the additional layer to the exposed adhesive surface. However, the presence of release layers can be challenging as it may limit the conversion process to a specific device. Furthermore, in the absence of release layers, the presence of adhesive layers may limit the manufacturer's ability to form the web of the intermediate electro-optic laminate, thereby increasing storage and transportation costs.

[0018] Designing chemically resistant electro-optic devices while simultaneously developing a cost-effective and convenient manufacturing process is challenging because different objectives require different formulations and manufacturing strategies. The inventors of this invention have unexpectedly discovered that using an intermediate electro-optic laminate containing a non-adhesive layer and without a release layer, a chemically resistant electro-optic device can be provided, which can be manufactured through a cost-effective and flexible process. This manufacturing method includes a thermoforming step in which a thermoplastic film is attached to the adhesive layer of the intermediate electro-optic laminate. The thermoforming step further includes pressing the thermoplastic film and the adhesive layer together to form a substrate layer on the adhesive layer. Summary of the Invention

[0019] In one embodiment, the present invention relates to a chemically resistant multilayer electro-optic device, comprising, in sequence: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, a first adhesive layer, and a second substrate layer. The first adhesive layer comprises: 20 to 80% by weight of polyurethane, a cross-linked acrylic polymer, or a mixture of polyurethane and cross-linked acrylic polymer, excluding solvent, based on the weight of the first adhesive layer; and 20 to 80% by weight of polyvinyl alcohol, excluding solvent, based on the weight of the first adhesive layer. The polyvinyl alcohol contains acetyl-acetyl functional groups in its molecular structure. The second substrate layer is formed using a thermoplastic film having a surface, the thermoplastic film comprising a thermoplastic resin. The thermoplastic film has a surface treatment such that the surface of the thermoplastic film contains polar functional groups. At least a portion of the polar functional groups are covalently bonded to the polyvinyl alcohol of the first adhesive layer, the covalent bond being formed by the reaction of the acetyl acetate functional groups of the polyvinyl alcohol with the polar functional groups on the surface of the thermoplastic film. The thermoplastic film used to form the second substrate layer may comprise a thermoplastic resin selected from the group consisting of polyethylene, polypropylene, polybutene, polyethylene terephthalate, ethylene copolymers, propylene copolymers, butene copolymers, and mixtures thereof. The polyvinyl alcohol may have a degree of hydrolysis of 90% to 99%. The polyvinyl alcohol may be crosslinked, formed by reacting polyvinyl alcohol with a crosslinking agent. The crosslinking agent may be selected from the group consisting of dialdehyde, diamine, and organozirconates. The crosslinking agent may be glyoxal, ZrO(OH)Cl*nH2O, and (NH4)2ZrO(CO3)2, or mixtures thereof. The polyvinyl alcohol may have a number average molecular weight of 1,000 to 1,000,000 Daltons.

[0020] The first adhesive layer may further include a UV absorber. The UV absorber may be water-soluble or water-dispersible. The first adhesive layer may further include a light stabilizer. The light stabilizer may be water-soluble or water-dispersible. The light stabilizer may be a hindered amine light stabilizer (HALS). The first adhesive layer may have a thickness of 1 to 10 micrometers. The chemical-resistant electro-optic device may further include a second adhesive layer disposed between the first substrate layer and the first transparent electrode layer, or disposed between the first transparent electrode layer and the electro-optic material layer. The chemical-resistant electro-optic device may include a second adhesive layer disposed between the first substrate layer and the first transparent electrode layer, and a third adhesive layer disposed between the first transparent electrode layer and the electro-optic material layer.

[0021] The electro-optic material layer of this chemical-resistant multilayer electro-optic device includes an electrophoretic medium comprising charged pigment particles, a charge control agent, and a nonpolar liquid. This electrophoretic medium can be encapsulated within multiple microcapsules or microcells. The electrophoretic medium may contain two or more charged particles with different colors and / or charge sizes. In the case of a microcell device, the device is an electrophoretic medium encapsulated within multiple microcells, each microcell comprising a microcell sublayer, a microcell wall, a microcell opening, and a sealing layer, the sealing layer being in contact with the second electrode layer.

[0022] The second electrode layer of the chemically resistant electro-optic device may comprise a conductive polymer. The electropolymer of the second electrode layer may be selected from the group consisting of poly(3,4-ethyldioxythiophene):polystyrene sulfonate (PEDOT-PSS), polyacetylene, polyphenylene sulfide, polystyrene, and combinations thereof.

[0023] When the first adhesive layer comprises polyurethane or a mixture of polyurethane and crosslinked acrylic polymer, the glass transition temperature of the polyurethane may be below 0°C, below -10°C, below -20°C, or below -30°C. The polyurethane may be crosslinked. The polyurethane in the first adhesive layer may be crosslinked. The polyurethane may have a number average molecular weight of 1,000 to 2,000,000 Daltons.

[0024] In cases where the first adhesive layer comprises a crosslinked acrylic polymer or a mixture of polyurethane and a crosslinked acrylic polymer, the crosslinked acrylic polymer may be formed from a self-crosslinked acrylic polymer. The crosslinked acrylic polymer may be an acrylic polymer containing epoxy functional groups. The crosslinked acrylic polymer may be a self-crosslinked epoxy acrylic emulsion, which is an acrylic polymer formed through emulsion polymerization. The weight ratio of the self-crosslinked acrylic polymer to polyvinyl alcohol may be from 0.15 to 0.30.

[0025] The chemically resistant multilayer electro-optic device of the present invention may include a piezoelectric layer comprising a piezoelectric material. The piezoelectric layer may be disposed between the first transparent electrode layer and the electro-optic material layer, or between the second electrode layer and the electro-optic material layer.

[0026] In another embodiment, the present invention relates to a method for manufacturing a chemically resistant multilayer electro-optic device. The chemically resistant multilayer electro-optic device sequentially comprises: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, a first adhesive layer, and a second substrate layer. The method for manufacturing the chemically resistant multilayer electro-optic device comprises: (a) providing an electro-optic sheet sequentially comprising: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, and a second electrode layer, the second electrode layer comprising a conductive polymer; and (b) forming a wet film on the second electrode layer of the electro-optic sheet by applying an aqueous adhesive composition to the second electrode layer, the aqueous adhesive composition comprising (i) 20 to 80% by weight of polyvinyl alcohol, excluding solvent, based on the weight of the aqueous adhesive composition, the polyvinyl alcohol containing acetyl-acetyl functional groups in its molecular structure. (i) a base; (ii) 20 to 80% by weight of polyurethane, a self-crosslinking acrylic polymer, or a mixture of polyurethane and a self-crosslinking acrylic polymer, excluding solvent, based on the weight of the aqueous adhesive composition; and (iii) an aqueous carrier; (c) forming an intermediate electro-optic laminate by applying heat to cure the wet film, the intermediate electro-optic laminate sequentially comprising: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, and an adhesive film, the adhesive film comprising 20 to 80% by weight of polyurethane, a self-crosslinking acrylic polymer, or a mixture ... (d) A mixture of a polymer or polyurethane or crosslinked acrylic polymer, and 20 to 80% by weight of polyvinyl alcohol, excluding solvent, based on the weight of the adhesive film, the polyvinyl alcohol containing acetyl-acetyl functional groups, wherein the adhesive film of the intermediate electro-optic laminate is non-adhesive at room temperature; and (d) providing a thermoplastic film having a surface, the thermoplastic film comprising a thermoplastic resin selected from the group consisting of polyethylene, polypropylene, polybutene, polyethylene terephthalate, ethylene copolymers, propylene copolymers, butene copolymers, and mixtures thereof, the thermoplastic film having a surface treatment. (e) The thermoplastic film surface contains polar functional groups; and the thermoplastic film is laminated with the intermediate electro-optic laminate at a temperature of 60°C to 100°C to form a chemically resistant multilayer electro-optic device, wherein the first adhesive layer of the chemically resistant multilayer electro-optic device is disposed between the second substrate layer and the second electrode layer, the second substrate layer comprising a thermoplastic film, wherein at least a portion of the polar functional groups on the surface of the thermoplastic film reacts with the acetyl acetyl functional groups of the polyvinyl alcohol of the adhesive film, such that the surface of the thermoplastic film of the second substrate layer is covalently bonded to the polyvinyl alcohol of the first adhesive layer.

[0027] The aqueous adhesive composition may also contain 0.5 to 8% by weight of a crosslinking agent, excluding solvent, based on the weight of the aqueous adhesive composition; the adhesive film of the intermediate electro-optic laminate formed in the curing step contains 20 to 80% by weight of crosslinked polyvinyl alcohol, excluding solvent, based on the weight of the adhesive film, and the crosslinked polyvinyl alcohol of the adhesive film contains crosslinked acetyl acetyl functional groups and non-crosslinked acetyl acetyl functional groups.

[0028] If the aqueous adhesive composition contains a self-crosslinking acrylic polymer or a mixture of polyurethane and a self-crosslinking acrylic polymer, the self-crosslinking acrylic polymer may contain one or more epoxy functional groups.

[0029] The electro-optic material layer may include an electrophoretic medium, which may contain charged pigment particles, charge control agents, and a nonpolar liquid. The electrophoretic medium may be encapsulated in multiple microcells or multiple microcapsules. If the electrophoretic medium is encapsulated in multiple microcells, each microcell may include a microcell basal layer, a microcell wall, a microcell opening, and a sealing layer, which is in contact with the second electrode layer.

[0030] The second electrode layer may comprise a conductive polymer. This electropolymer may be selected from the group consisting of poly(3,4-ethyldioxythiophene): polystyrene sulfonate (PEDOT-PSS), polyacetylene, polyphenylene sulfide, polystyrene, and combinations thereof.

[0031] This method may include the step of forming the web of the intermediate electro-optic laminate after its formation. Then, a thermoplastic film is laminated together with the intermediate electro-optic laminate at a temperature of 60°C to 100°C, a process that can be performed in a roll-to-roll process. In this step, the roll-to-roll process means that the web of the intermediate electro-optic laminate and the web of the thermoplastic film are simultaneously unfolded upstream, moved parallel to each other to the hot-pressing stage, and, while passing through the hot-pressing stage, the thermoplastic film and the adhesive film of the intermediate electro-optic laminate are pressed together at an elevated temperature (60°C to 100°C). Then, a continuous film containing the thermoplastic film attached to the intermediate electro-optic laminate can be rolled up downstream of the hot-pressing stage. Simple Explanation of the Diagram

[0032] Figure 1 illustrates a partial side view of multiple microcellular structures before filling and sealing.

[0033] Figure 2A illustrates a side view of a portion of the electro-optic device comprising microcells according to the present invention.

[0034] Figure 2B shows a side view of a portion of the electro-optic device comprising microcapsules according to the present invention.

[0035] Figure 3A illustrates a partial side view of an electro-optic sheet that can be used to form an intermediate electro-optic laminate containing microcells.

[0036] Figure 3B illustrates a partial side view of an electro-optic sheet that can be used to form an intermediate electro-optic laminate containing microcapsules.

[0037] Figure 4A illustrates a partial side view of an intermediate electro-optic laminate, which can be used to form an electro-optic device containing microcells.

[0038] Figure 4B illustrates a partial side view of an intermediate electro-optic laminate, which can be used to form an electro-optic device containing microcapsules.

[0039] Figure 5A is a schematic diagram of the manufacturing process for the intermediate electro-optic laminate.

[0040] Figure 5B shows a simplified schematic diagram of the side view of the intermediate electro-optic laminate.

[0041] Figures 6A and 6B illustrate the hot stamping process for manufacturing electro-optic devices.

[0042] Figure 7 shows the process of manufacturing microcells using a roll-to-roll process.

[0043] Figures 8A and 8B detail the use of photolithography to create microcells by applying a photomask to a conductive film coated with a thermosetting precursor.

[0044] Figures 8C and 8D detail alternative embodiments of fabricating microcell arrays using photolithography. In Figures 8C and 8D, a combination of top and bottom exposure is used, so that the microcell walls are cured by exposure to the top photomask in one lateral direction, and the walls in the other lateral direction are cured by exposure to the bottom of an opaque substrate conductor film.

[0045] Figures 9A-9D illustrate the steps of filling and sealing the microcell array.

[0046] Figure 10A illustrates a side view of the intermediate electro-optic laminate of the present invention, which includes a piezoelectric material layer disposed between the electro-optic material layer and the second electrode layer.

[0047] Figure 10B illustrates a side view of a chemical-resistant electro-optic device of the present invention, which is formed from the intermediate electro-optic laminate shown in Figure 10A.

[0048] Figure 11A illustrates a side view of the intermediate electro-optic laminate of the present invention, which includes a piezoelectric material layer disposed between the electro-optic material layer and the first light-transmitting electrode layer.

[0049] Figure 11B illustrates a side view of a chemical-resistant electro-optic device of the present invention, which is formed from the intermediate electro-optic laminate shown in Figure 11A.

[0050] Figures 12-15 illustrate side views of various intermediate electro-optic laminates of the present invention, which include a piezoelectric material layer. Implementation

[0051] Detailed Description of the Invention

[0052] The term "excluding solvents" in the weight of the first adhesive layer (or aqueous adhesive composition) of this invention means that the weight of the adhesive layer does not include water and other solvents that may be present in the adhesive layer.

[0053] Unless otherwise stated, the term "molecular weight" or "MW" as used herein refers to quantity average molecular weight. Quantity average molecular weight can be measured by gel permeation chromatography.

[0054] As used herein, the term "excluding solvent" in relation to the weight of a composition, membrane, or device layer means the weight of the composition, membrane, or device layer minus the weight of one or more solvents present. The solvent may be water, an organic solvent, or a combination of water and an organic solvent.

[0055] As used herein, the term "aqueous carrier" in relation to the composition refers to water, or a combination of water and organic solvents present in the composition. The components of the aqueous carrier may be added to the composition during the preparation process, including carriers or impurities of the raw materials.

[0056] The "degree of hydrolysis" of polyvinyl alcohol (PVA) refers to the percentage of acetate groups in the polymer that have been hydrolyzed into hydroxyl groups. Typically, PVA is manufactured by hydrolyzing the corresponding polyvinyl acetate. Unless completely hydrolyzed, the final polymer contains hydroxyl groups and unhydrolyzed acetate groups. The degree of hydrolysis (DH) is reported as a percentage by PVA manufacturers. The reported degree of hydrolysis value is derived from the following formula: DH = [(number of hydroxyl units in the polymer) × 100] / (number of hydroxyl units in the polymer + number of acetate units in the polymer). The degree of hydrolysis can be determined by proton NMR. In the case of PVA comprising acetyl-acetyl functional groups in this invention, the number of acetyl-acetyl functional groups does not affect the degree of hydrolysis, as this number is not a variable in the above formula.

[0057] The "glass transition temperature" of polymers (such as polyurethane) is the temperature at which the polymer transitions from a glassy state to a softer state. The glass transition state is measured using differential scanning calorimetry (DSC).

[0058] As used herein, the term "acrylic polymer" refers to polymers made using esters of acrylic acid, esters of methacrylic acid, acrylic acid and its derivatives, methacrylic acid and its derivatives, acrylic acid and its derivatives, and methacrylic acid and its derivatives. The term "acrylic polymer" also includes copolymers made from combinations of monomers.

[0059] As used in this article, "webbed" refers to a long, continuous roll of a flexible laminate or membrane.

[0060] The terms "crosslinking agent" and "crosslinker" are synonymous and refer to a reagent that can react with crosslinkable polymers to form crosslinked polymers.

[0061] The term "self-crosslinking acrylic polymer" as used in this article refers to acrylic polymers that can form crosslinked polymers by forming bonds between their own chains (same or different molecules), usually without the need for a crosslinking agent.

[0062] The term "non-adhesive" refers to the adhesive layer of an intermediate electro-optic laminate at room temperature, wherein the adhesive layer is attached to the surface of the intermediate electro-optic laminate, meaning that the adhesive layer will not adhere to itself or other non-adhesive materials at room temperature. For the adhesive layer located on the surface of the intermediate electro-optic laminate, the term "non-adhesive" means that the intermediate electro-optic laminate can be stored in a web at room temperature. With a corresponding adhesive layer, it is impractical to form the laminate into a useful web for later use.

[0063] The term "room temperature" refers to a temperature between 20°C and 30°C.

[0064] The term "use period" of a composition refers to the amount of time that the composition remains in a workable liquid form at a specified temperature.

[0065] As used herein, the term "chemical-resistant electro-optic device" refers to the integrity of an electro-optic display after exposure to organic solvents or water, or even after immersion in such solvents for a specified period of time.

[0066] The term "transmittance" as used herein refers to a layer that transmits sufficient light to allow an observer to see through the layer in order to observe changes in the display state of the electrophoretic medium, which are typically visible through the transmittance electrode layer and adjacent substrates (if present); in cases where the electrophoretic medium exhibits changes in reflectance at non-visible wavelengths, the term "transmittance" should of course be interpreted as referring to the transmission of the relevant non-visible wavelengths.

[0067] The term "contrast ratio" (CR) used in electro-optic displays is defined as the ratio of the light intensity of the brightest color (white) to the darkest color (black) that the display can produce. High contrast ratio or CR is generally considered a desirable display characteristic.

[0068] Piezoelectricity is the accumulation of electrical charge in a solid material in response to applied mechanical stress. Suitable piezoelectric materials may include polyvinylidene fluoride (PVDF), quartz (SiO2), aluminosilicate (AlPO4), gallium orthophosphate (GaPO4), tourmaline, barium titanate (BaTiO3), lead zirconate titanate (PZT), zinc oxide (ZnO), aluminum nitride (AlN), lithium tantalate, lanthanum gallium silicate, potassium, sodium tartrate, and any other known piezoelectric materials. Piezoelectricity can be used to drive the pigments of the electrophoretic material in an electro-optic display to generate an electrical charge, thereby energizing the electro-optic display. The electro-optic display can operate without a power source, energized solely by the electrical charge generated by the piezoelectric material. For example, in the case of an electro-optic display with an electrophoretic material, voltage can be generated by bending or introducing stress into the piezoelectric material, and this voltage can be used to cause the color pigments of the electrophoretic material in the electro-optic display to move. Electro-optic displays comprising electrophoretic media and piezoelectric materials have been previously disclosed, for example in U.S. Patent Nos. 7,002,728 and 7,679,814.

[0069] Figure 1 illustrates a partial side view of the structure of multiple microcells 100 before filling and sealing. Each microcell includes a microcell base 101, a microcell wall 102, and a microcell opening 103.

[0070] Structure of electro-optic devices containing microcell or microcapsule structures

[0071] Figure 2A illustrates a partial side view of an electro-optic device 200 comprising a plurality of microcells according to the present invention. An example of this electro-optic device 200 includes a first substrate layer 211, a first transparent electrode layer 210, a microcell layer 220, a sealing layer 230, a second electrode layer 250, a first adhesive layer 240, and a second substrate layer 212. The microcell layer 220 comprises a plurality of microcells defined by a microcell base 101, a microcell wall 102, and a microcell opening 103. Each of the plurality of microcells contains an electrophoretic medium 225 comprising charged particles in a nonpolar fluid. The electrophoretic medium 225 may also contain a charge control agent. The microcells are sealed by the sealing layer 230, which spans the microcell openings 103 of the plurality of microcells. The second electrode layer 250 is in contact with the sealing layer 230. The electro-optic device may include a second adhesive layer (not shown in Figure 2A) disposed between the sealing layer 230 and the second electrode layer 250. The electro-optic material layer 260 of the electro-optic device 200 includes a microcell layer 220 and a sealing layer 230. An electric field source (not shown in FIG. 2A) can be connected to a first transparent electrode layer 210 and a second electrode layer 250. Applying an electric field to the electrophoretic material layer 260 causes charged particles to migrate through the electrophoretic medium, thereby generating an image observed by an observer on the viewing side 205 of the electro-optic device 200. An optional primer layer (not shown in FIG. 2A) can be configured between the first transparent electrode layer 210 and the plurality of microcells.

[0072] Figure 2B illustrates a partial side view of an electro-optic device 290 comprising multiple microcapsules according to the present invention. An example of this electro-optic device 290 includes a first substrate layer 211, a first transparent electrode layer 210, an electro-optic material layer 265, a second adhesive layer 248, a second electrode layer 250, the first adhesive layer 240, and a second substrate layer 212. The electro-optic material layer 265 comprises multiple microcapsules and an adhesive. The microcapsules include an electrophoretic medium comprising charged particles in a nonpolar fluid. The electrophoretic medium may also contain a charge control agent. An electric field source (not shown in Figure 2B) may connect the first transparent electrode layer 210 and the second electrode layer 250. Applying an electric field to the electrophoretic material layer 265 causes charged particles to migrate through the electrophoretic medium, thereby generating an image observed by an observer on the viewing side of the electro-optic device 200, the viewing side being the side of the device closest to the first substrate layer 211.

[0073] The electro-optic device example illustrated in Figure 2A can be constructed from an intermediate electro-optic laminate 400, as shown in Figure 4A. The intermediate electro-optic laminate 400 can also be constructed from an electro-optic sheet 300, as shown in Figure 3A. The electro-optic sheet 300 includes a first substrate layer 211, a first transparent electrode layer 210, a microcell layer 220, a sealing layer 230, and a second electrode layer 250. The electro-optic material layer 260 includes the microcell layer 220 and the sealing layer 230. The intermediate electro-optic laminate 400 in Figure 4A includes a first substrate layer 211, a first transparent electrode layer 210, a microcell layer 220, a sealing layer 230, a second electrode layer 250, and an adhesive film 245.

[0074] The electro-optic device example illustrated in Figure 2B can be constructed from an intermediate electro-optic laminate 490, as shown in Figure 4B. The intermediate electro-optic laminate 490 can also be constructed from an electro-optic sheet 390, as shown in Figure 3B. The electro-optic sheet 390 includes a first substrate layer 211, a first transparent electrode layer 210, an electro-optic material layer 265 containing microcapsules and an adhesive, a second adhesive layer 248, and a second electrode layer 250. The intermediate electro-optic laminate 490 in Figure 4B includes a first substrate layer 211, a first transparent electrode layer 210, an electro-optic material layer 265 containing microcapsules and an adhesive, a second electrode layer 250, a second adhesive layer 248, and an adhesive film 245.

[0075] The electro-optic sheet 300 of Figure 3A can be transformed into the intermediate electro-optic laminate 400 of Figure 4A by coating an aqueous adhesive composition (252) onto the second electrode layer 250 and thermally curing the aqueous adhesive composition 252. Alternatively, curing can be performed by exposing the adhesive layer to UV light. An example of the process for manufacturing the intermediate electro-optic laminate 400 from the electro-optic sheet 300 is illustrated in Figure 5A. Specifically, an aqueous adhesive composition 242 is applied to the second electrode layer 250 of the electro-optic sheet 300, and then the applied aqueous adhesive composition is heated to form an adhesive film 245. Figure 5B shows a simplified illustration of the intermediate electro-optic laminate 400.

[0076] The intermediate electro-optic laminate can be prepared, safely stored, and transported to various locations for use in the manufacture of electro-optic devices. In fact, the adhesive layer of the intermediate electro-optic laminate is non-adhesive, and the intermediate electro-optic laminate can be rolled into a web for efficient storage.

[0077] An example of the manufacturing process for an electro-optic device from an intermediate electro-optic laminate is illustrated in Figures 6A and 6B. Figure 6A shows a thermoplastic film 212 attached to the adhesive film 245 of the intermediate electro-optic laminate 400 to provide the electro-optic device 200, wherein the thermoplastic film 212 serves as the second substrate layer of the electro-optic device 200. The thermoplastic film 212 is attached to the adhesive film (245) of the intermediate electro-optic laminate 400 by pressing the two components together at an elevated temperature. Figure 6B illustrates an example of this processing step using a hot stamping device. As shown in Figure 6B, this process step can be performed via a roll-to-roll process. The thermoplastic film 212 and the intermediate electro-optic laminate 400, derived from two different webs, are fed parallel to each other into a hot stamping station (610), where pressure is applied at an elevated temperature. The pressure at elevated temperatures allows the adhesive film 245 of the intermediate electro-optic laminate 400 to adhere to the thermoplastic film (212), providing an electro-optic device 200 comprising a second substrate layer 212 adhered to the first adhesive layer 240 of the device. The manufactured device 200 can be collected in a web (620). At a later time and in different locations, the web can be easily converted into the final device by cutting portions of the web to appropriate sizes. As described above, the manufactured electro-optic device may contain microcells or microcapsules, depending on the structure of the intermediate electro-optic laminate (400 or 490).

[0078] Formation of microcell arrays

[0079] Techniques for constructing microcells. Microcells can be formed in batch processes or in a continuous roll-to-roll process as disclosed in U.S. Patent No. 6,933,098. The latter provides a continuous, low-cost, high-volume manufacturing technique for producing compartments used in a variety of applications, including useful reagent delivery and electro-optical displays. Microcell arrays suitable for use in this invention can be manufactured using microimprinting, as illustrated in FIG7. A punch (700) can be positioned above or below the web 704 (not shown); however, alternative configurations are feasible. See, for example, U.S. Patent No. 7,715,088, which is incorporated herein by reference in its entirety. A conductive substrate can be constructed by forming a conductive film 701 on a polymer substrate that becomes the bottom (or backing layer) of the device microcells. The conductive film serves as the first light-transmitting electrode layer of the device. A composition comprising a thermoplastic, thermosetting, or a precursor thereof 702 is then coated onto the conductive film. The thermoplastic or thermosetting precursor layer is embossed with a punch in the form of a roller, plate, or belt at a temperature higher than the glass transition temperature of the thermoplastic or thermosetting precursor layer.

[0080] Thermoplastic or thermosetting precursors used to prepare microcells can be polyfunctional acrylates or methacrylates, vinyl ethers, epoxides, and their oligomers or polymers. Combinations of polyfunctional epoxides and polyfunctional acrylates are also very useful for obtaining the desired physical-mechanical properties. Crosslinkable oligomers that impart flexibility, such as carbamate acrylates or polyester acrylates, can be added to improve the flexural strength of the imprinted microcells. The composition may contain polymers, oligomers, monomers, and additives, or only oligomers, monomers, and additives. The glass transition temperature (or Tg) of such materials is typically in the range of about -70°C to about 150°C, or about -20°C to about 50°C. Microimprinting processes are generally performed at temperatures above the Tg. The microimprinting temperature and pressure can be controlled using a heated die or a heated housing substrate pressed against it by a mold.

[0081] As shown in Figure 7, the mold detaches during or after the precursor layer hardens to reveal the microcellular array 503. Precursor layer hardening can be achieved by cooling, solvent evaporation, radioactive crosslinking, thermal crosslinking, or moisture crosslinking. If the curing of the thermosetting precursor is achieved by UV radiation, UV light can be irradiated onto the transparent conductor film from the bottom or top of the web, as shown in both figures. Alternatively, a UV lamp can be placed inside the mold. In this case, the mold must be transparent to allow UV light to pass through a pre-patterned punch onto the thermosetting precursor layer. The punch can be prepared by any suitable method, such as diamond turning or photoresist, followed by etching or electroplating. The punch master template can be manufactured by any suitable method, such as electroplating. Electroplating involves sputtering a thin layer (typically 3000 Å) of a metal (such as chromium-containing high-nickel) onto a glass substrate. The mold is then coated with a layer of photoresist and exposed to UV light. A photomask is placed between the UV and photoresist layers. The exposed areas of the photoresist harden. The unexposed areas are then removed by cleaning with a suitable solvent. The remaining hardened photoresist is dried and sputtered again in a thin layer of a metal. The master template is then ready for electroforming. A typical material for electroforming is nickel-cobalt. Alternatively, the master template can be made of nickel by electroforming or electroless nickel deposition. The mold base plate is typically between approximately 50 and 400 micrometers. The master template can also be manufactured using other microengineering techniques, including e-beam writing, dry etching, chemical etching, laser writing, or laser interference as described in “Replication techniques for micro-optics”, SPIE Proc., Vol. 3099, pp. 76-82 (1997). Alternatively, the mold can be manufactured using photomachining of plastics, ceramics, or metals.

[0082] Before applying the UV-curable resin composition, the mold may be treated with a release agent to facilitate the demolding process. The UV-curable resin may be degassed before dispensing and may optionally contain a solvent. This solvent (if present) is readily evaporable. The UV-curable resin is dispensed onto the punch by any suitable means, such as coating, dipping, pouring, etc. The dispenser may be movable or stationary. The conductive film is stacked on the UV-curable resin. If necessary, pressure may be applied to ensure proper adhesion between the resin and the plastic and to control the thickness of the microcell substrate. This pressure may be applied using a laminating roller, vacuum forming, a pressure device, or any other similar means. If the punch is metallic and opaque, the plastic substrate is typically transparent to the photochemical rays used to cure the resin. Conversely, the punch may be transparent to photochemical rays, and the plastic substrate may be opaque. For good transfer of molding features to the transfer sheet, the conductive film must have good adhesion to the UV-curable resin, which should have good release properties to the mold surface.

[0083] The microcell array of this invention typically comprises a pre-formed conductive film, such as indium tin oxide (ITO) conductor wires; however, other conductive materials, such as silver or aluminum, can be used. The conductive layer can be supported or integrated into a substrate layer, such as polyethylene terephthalate, polybutylene terephthalate, polyarylamine, polyimide, polycyclic olefin, polyurethane, epoxy, and composites thereof. A radiocurable polymer precursor layer can be coated onto the conductive film. The film and precursor layer are then radio-exposed to an image to form a microcell wall structure. After exposure, the precursor material is removed from the unexposed areas, leaving cured microcell walls that bond the conductive film / support web. Image exposure can be completed by using UV or other forms of radiation through a photomask to create an exposure image or predetermined pattern of the radiocurable material coated on the conductive film. Although generally unnecessary, a photomask can be placed and the conductor film, i.e., the ITO lines, aligned so that the transparent photomask portion aligns with the space between the ITO lines, and the opaque photomask portion aligns with the ITO material (intended for use in the microcell substrate region).

[0084] Lithography. Microcells can also be manufactured using lithography. The lithography process for manufacturing microcell arrays is described in Figures 8A and 8B. As shown in Figures 8A and 8B, a microcell array 800 is prepared by exposing a radiocurable material 801 coated onto a conductive film 802 using known methods to UV light (or alternatively, other forms of radiation, electron beams, etc.) through a photomask 806, and forming microcell walls 102 corresponding to the image projected through the photomask 806. The conductive film 802 is preferably mounted on a substrate layer (803), which may contain a plastic material.

[0085] In the photomask 806 of Figure 8A, the dark squares represent the opaque areas 804 of the photomask, and the spaces between the dark squares represent the transparent areas 805 of the photomask 806. UV light irradiates the radiocurable material 801 through the transparent areas 805 of the photomask 806. Exposure is preferably performed directly on the radiocurable material 801, i.e., the UV light does not pass through the substrate layer 803 or the conductor film 802 (upper exposure). Therefore, the substrate 803 or the conductor film 802 does not need to be transparent to UV light or other wavelengths of radiation used.

[0086] As shown in Figure 8B, the exposed areas (such as the microcell wall 102) harden. The unexposed areas (protected by the opaque area 804 of the photomask 806) are then removed using a suitable solvent or developer to form microcells 807. The solvent or developer is selected from those commonly used to dissolve or reduce the viscosity of radiocurable materials, such as methyl ethyl ketone (MEK), toluene, acetone, and isopropanol. The microcells can be prepared similarly by placing the photomask under a conductor film / substrate support web. In this case, UV light irradiates from the bottom through the photomask, and the substrate must be transparent to the radiation.

[0087] Image exposure. Another alternative method for preparing the microcell array of the present invention by image exposure is illustrated in Figures 8C and 8D. When using opaque conductor lines, these conductor lines can serve as photomasks for bottom-exposure. The durable microcell walls are formed by additional exposure from above through a second photomask having opaque lines perpendicular to the conductor lines. Figure 8C illustrates the fabrication of the microcell array 800 of the present invention using the top and bottom exposure principle. The conductor film 802 is opaque and has a line pattern. The radiocurable material 801 coated on the conductor film 802 and the substrate layer 803 is exposed from the bottom through the conductor film 802, which serves as the first photomask. The second exposure is performed from the "top" side through a second photomask 816 having a line pattern perpendicular to the conductor film 802. The spaces 815 between the lines 814 are substantially transparent to UV light. In this process, the microcell wall material 801 is oriented in one direction to cure from bottom to top and in the vertical direction to cure from top to bottom, and they are bonded together to form the microcell wall 102 of the integral microcell 807. As shown in FIG8D, the unexposed areas are then removed by solvent or developer as described above to reveal the microcell 807.

[0088] The microcells can be constructed from thermoplastic elastomers that have good compatibility with the microcells and do not interact with the medium. Examples of useful thermoplastic elastomers include ABA and (AB)n-type diblock, triblock, and multiblock copolymers, wherein A is styrene, α-methylstyrene, ethylene, propylene, or norbornene; B is butadiene, isoprene, ethylene, propylene, butene, dimethylsiloxane, or propylene sulfide; and A and B cannot be the same in the formula. The value n ≥ 1, preferably 1-10. Particularly useful are diblock or triblock copolymers of styrene or oxymethylstyrene, such as SB (poly(styrene-b-butadiene)), SBS (poly(styrene-b-butadiene-b-styrene)), SIS (poly(styrene-b-isoprene-b-styrene)), SEBS (poly(styrene-b-ethylene / butene-b-styrene)), poly(styrene-b-dimethylsiloxane-b-styrene), poly(α-methylstyrene-b-isoprene), poly(α-ene-b-isoprene-b-α-methylstyrene), poly(α-methylstyrene-b-propenesulfide-b-α-methylstyrene), and poly(α-methylstyrene-b-dimethylsiloxane-b-α-methylstyrene). Commercially available styrene block copolymers are particularly useful, such as the Kraton D and G series (from Kraton Polymer, Houston, Texas). Crystalline rubbers have also been found to be very useful, such as poly(ethylene-copoly-propylene-copoly-5-methylene-2-norbornene); or EPDM (ethylene-propylene-diene trimer) rubbers, such as Vistalon 6505 (obtained from Exxon Mobil, Houston, Texas) and its graft copolymers.

[0089] This thermoplastic elastomer can be dissolved in solvents or solvent mixtures that are immiscible with the carrier in the microcells, and whose specific gravity is less than that of the carrier. Low surface tension solvents are preferred for the coated composition because their wetting properties are superior to those of the microcell walls and fluids. Solvents or solvent mixtures with a surface tension below 35 dyne / cm or below 30 dyne / cm are preferred. Suitable solvents include alkanes (preferably C6-12 alkanes, such as heptane, octane, or Isopar solvent from Exxon Chemical Company, nonane, decane, and their isomers), cycloalkanes (preferably C6-12 cycloalkanes, such as cyclohexane and decahydronaphthalene), alkylbenzenes (preferably mono- or di-C1-6 alkylbenzenes, such as toluene, xylene, etc.), alkyl esters (preferably C2-5 alkyl esters, such as ethyl acetate, isobutyl acetate, etc.), and C3-5 alkyl alcohols (such as isopropanol and their isomers). Mixtures of alkylbenzenes and alkanes are particularly useful.

[0090] In addition to polymer additives, the polymer mixture may also include wetting agents (surfactants). Wetting agents (such as FC surfactants from 3M, Zonyl fluorinated surfactants from DuPont, fluoroacrylates, fluoromethyl acrylates, fluorinated long-chain alcohols, perfluorinated long-chain carboxylic acids and their derivatives, and Silwet polysiloxane surfactants from OSi in Greenwich, Connecticut) may also be included in the composition to improve the adhesion of the sealant to microcells and provide a more flexible coating process. Other components, including crosslinking agents (such as diazidides, such as 4,4'-diazidodiphenylmethane and 2,6-di-(4'-azidobenzylmethyl)-4-methylcyclohexanone), vulcanizing agents (such as 2-benzothiazole disulfide and tetramethylthiuram disulfide), polyfunctional monomers or oligomers (such as hexanediol, diacrylate, trimethylolpropane, triacrylate, divinylbenzene, diallyl phthalate), thermal initiators (such as dilauryl peroxide and benzoyl peroxide), and photoinitiators (such as isopropyl 9-oxosulfur (ITX), Irgacure 651 and Irgacure 369 from Ciba-Geigy), are also extremely useful for enhancing the physical and mechanical properties of the sealant through crosslinking or polymerization reactions during or after the coating process.

[0091] The microcell array 900 can be fabricated using any of the methods described above. As shown in the cross-sections of Figures 9A-9D, the microcell wall 102 extends upward from the microcell base 101 and the first light-transmitting electrode layer 210 (which serves as the first light-transmitting electrode layer of the electro-optic device) to form an open microcell. In one embodiment, the first light-transmitting electrode layer 210 is formed on or at the microcell base 101. Although Figures 9A-9D show the first light-transmitting electrode layer 210 as continuous and running on the microcell base 101, the first light-transmitting electrode layer 210 may also be continuous and running below or within the microcell base 101, or it may be interrupted by the microcell wall 102. Figure 2A illustrates a microcell array including the first light-transmitting electrode layer 210.

[0092] Next, the microcells are filled with an electrophoretic medium 225, which contains charged particles in a nonpolar fluid, to form a plurality of filled microcells. These microcells can be filled using various techniques. In some embodiments, a doctor blade coating can be used to fill the microcells to the depth of the microcell wall 102. In other embodiments, inkjet microinjection can be used to fill the microcells. In yet another embodiment, a microneedle array can be used to fill an array of microcells with the electrophoretic medium 225. Figure 9B illustrates the filled microcells 970.

[0093] As shown in Figure 9C, after filling, the microcells are sealed by applying an aqueous sealing composition to form a sealed microcell 980, which includes a sealing layer 230. In some embodiments, this sealing process may involve exposure to heat, dry hot air, or UV radiation. The sealing layer must have good barrier properties against the non-polar fluid of the electrophoretic medium 225. Figure 9C illustrates the filled and sealed microcells 980.

[0094] In an alternative embodiment, iterative lithography can be used to fill multiple individual microcells with a desired mixture. This process typically involves coating an empty microcell array with a layer of positive working photoresist, selectively opening a specific number of microcells by image exposure of the photoresist, developing the photoresist, filling the opened microcells with the desired mixture, and sealing the filled microcells by a sealing process. These steps can be repeated to create sealed microcells filled with other mixtures. This process can form large microcell sheets with desired proportions or concentrations of mixtures.

[0095] Sealing of filled microcells can be accomplished in many ways. One method involves mixing an aqueous sealing composition with an electrophoretic medium composition. The aqueous sealing composition may be immiscible with the electrophoretic composition, preferably having a lower specific gravity. These two compositions, the aqueous sealing composition and the electrophoretic medium composition, are thoroughly mixed and immediately applied to multiple microcells using a precision coating apparatus, such as a Meyer bar, gravure printing, doctor blade, trough coating, or slit coating. Excess fluid is scraped off using a brush or similar device. A small amount of a weak solvent or solvent mixture, such as isopropanol, methanol, or an aqueous solution thereof, can be used to clean residual fluid from the top surface of the microcell septa. The aqueous sealing composition is then separated from the electrophoretic medium composition and floats above the liquid electrophoretic medium composition. Alternatively, after filling the microcells with a mixture of the electrophoretic dielectric composition and the aqueous sealing composition, a substrate can be deposited on top to control the metering of the composition mixture and facilitate the phase separation of the aqueous sealing composition from the electrophoretic dielectric composition, thereby forming a uniform sealing layer. The substrate layer used can be a functional substrate of the final structure or a sacrificial substrate, such as a release substrate, which can be removed later. The aqueous sealing composition is then hardened in situ (i.e., upon contact with the electrophoretic dielectric composition) to form the sealing layer. Hardening of the aqueous sealing composition can be accomplished by UV or other forms of radiation, such as visible light, IR, or electron beams. Alternatively, if heat or moisture can be used to cure the aqueous sealing composition, then heat or moisture can also be used to harden it.

[0096] In another approach, the electrophoretic medium composition is first filled into microcells, followed by coating the filled microcells with an aqueous sealing composition. This coating can be achieved using conventional coating and printing processes, such as felt coating, inkjet printing, or other printing processes. In this approach, the sealing layer is formed in situ by hardening the aqueous sealing composition through solvent evaporation, radiation, heat, moisture, or interfacial reaction. Interfacial polymerization after UV curing is beneficial to the sealing process. Mismixing between the electrophoretic medium composition and the sealing film is significantly suppressed by the formation of a thin barrier layer at the interface through interfacial polymerization. The sealing is then completed by a post-curing step, such as by UV radiation. Using an aqueous sealing composition with a lower specific gravity than the electrophoretic medium composition can further reduce the degree of mismixing. Volatile organic solvents can be used to adjust the viscosity and thickness of the sealing film. The rheological properties of the aqueous sealing composition can be adjusted for optimal sealing performance and coatability. When volatile solvents are used for protective films, it is preferable that they are not miscible with the solvents in the electrophoretic media composition.

[0097] After the microcells are filled and sealed, the sealed array can be laminated with a second electrode layer 250 containing multiple electrodes. The second electrode layer 250 can be attached to the sealing layer 230 to form an electro-optic device 990, as shown in FIG. 9D. The second electrode layer 250 can be attached to the sealing layer 230 using an adhesive (the adhesive layer is not shown in FIG. 9D). The adhesive can be conductive. The adhesive of the adhesive layer can be a pressure-sensitive adhesive, a hot-melt adhesive, or a heat, water, or radiation-curable adhesive. The laminated adhesive can be post-cured by radiation (such as UV) through the upper conductive layer if the latter is transparent to radiation. In other embodiments, multiple electrodes can be directly bonded to the sealed microcell array. FIG. 9D illustrates an assembly 990 comprising filled and sealed microcells and first and second electrode layers (210 and 250).

[0098] Microcells can typically be any shape, and their size and shape can vary. Within the same system, microcells can have a uniform size and shape. However, there can be microcells with mixed shapes and sizes. The openings of microcells can be circular, square, rectangular, hexagonal, or any other shape. The size of the partitions between the openings of microcells can also vary. The size of individual microcells can range from about 1 × 10¹ to about 1 × 10⁶ μm², from about 1 × 10² to about 1 × 10⁶ μm², or from about 1 × 10³ to about 1 × 10⁵ μm².

[0099] The depth of the microcell can range from about 5 to about 200 μm, or from about 10 to about 100 μm. The ratio of the microcell opening to the total area ranges from about 0.05 to about 0.95, or from about 0.4 to about 0.9.

[0100] Electrophoretic medium.

[0101] In this invention, electrophoretic medium refers to a composition contained in microcells or microcapsules. For display applications, microcells or microcapsules may be filled with at least one type of charged pigment particles in a nonpolar fluid. The electrophoretic medium may contain one type of charged particles, or more than one type of particles with different colors, charges, and charge polarities. The charged particles move through the electrophoretic medium under the influence of an electric field applied across the electro-optic material layer. The charged particles may be inorganic or organic pigments that have undergone polymer surface treatment to improve their stability. The electrophoretic medium may contain pigments of white, black, cyan, magenta, yellow, blue, green, red, and other colors. The electrophoretic medium may also contain charge control agents, charge adjuvants, rheological modifiers, and other additives. Examples of nonpolar fluids include hydrocarbons such as Isopar, decalin, 5-ethylenyl-2-norbornene, fatty oils, paraffin oils, and silicone fluids; aromatic hydrocarbons such as toluene, xylene, phenyl styrene, dodecylbenzene, or alkylnaphthalene; halogenated solvents such as perfluoronaphthene, perfluorotoluene, perfluoroxylene, dichlorotrifluorotoluene, 3,4,5-trichlorotrifluorotoluene, chloropentafluorobenzene, dichlorononane, or pentachlorobenzene; and perfluorinated solvents such as FC-43, FC-70, or FC-5060 from 3M Company, St. Paul MN; low molecular weight halogenated polymers such as poly(perfluoropropylene oxide) from TCI America, Portland, Oregon; poly(chlorotrifluoroethylene) such as Halocarbon Oils from Halocarbon Product Corp., River Edge, NJ; and perfluoropolyalkyl ethers such as Galden from Ausimont or DuPont. Delaware's KrytoxOils and Greases K-Fluid series; derived from Dow-corning's polydimethylsiloxane-based polysiloxane oil (DC-200).

[0102] The electrophoretic medium may contain two or more types of charged particles. The electrophoretic medium may contain four types of charged particles: Type I, Type II, Type III, and Type IV charged particles. Type I, Type II, Type III, and Type IV charged particles may contain Type I, Type II, Type III, and Type IV pigments, and each possesses a first, second, third, and fourth color, respectively. The first, second, third, and fourth colors may be different from each other. Type I particles may contain inorganic pigments and possess a first charge polarity. Type II and Type III particles may possess a second charge polarity opposite to the second charge polarity. Type IV particles may possess either a first or second charge polarity. Type I particles may be white. Type II, third, and fourth charged particles may possess colors selected from the group consisting of cyan, magenta, and yellow.

[0103] sealing layer

[0104] The microcells are sealed with a sealing layer 230 that spans the microcell openings of multiple microcells.

[0105] The sealing layer must provide a barrier to the electrophoresis medium, preventing the nonpolar fluid from being removed from the microcells. Furthermore, because the sealing layer contacts the electrophoresis medium and seals it within the microcavities, it must (1) be virtually insoluble in the nonpolar fluids of the electrophoresis medium, and (2) act as a good barrier to nonpolar fluids, preventing them from diffusing out of the microcells during the device's lifespan. Poor barrier properties of the sealing layer to nonpolar fluids can lead to a reduction in fluid flow from the electrophoresis medium and sealing layer sagging. In certain applications where the electrophoresis apparatus may be exposed to harsh environments, such as exposure to organic solvents or water, or even immersion in such solvents, the sealing layer must also be waterproof. That is, the sealing layer must be resilient in water and must protect the electrophoresis medium under these conditions.

[0106] Water-based adhesive composition

[0107] The adhesive film of the intermediate electro-optic laminate of the present invention, and the first adhesive layer of the subsequent electro-optic device, are formed by initially applying an aqueous adhesive composition to the second electrode layer, as shown in FIG5A. The coating of the aqueous adhesive composition can be performed by various coating or printing methods. The aqueous adhesive composition may contain (a) 20% to 80% by weight of polyurethane, self-crosslinking acrylic polymer, or a combination of polyurethane and self-crosslinking acrylic polymer, excluding solvent, based on the weight of the aqueous adhesive composition; (b) 20% to 80% by weight of polyvinyl alcohol, excluding solvent, based on the weight of the aqueous adhesive composition, wherein the polyvinyl alcohol contains acetyl-acetyl functional groups in its molecular structure; and (c) 10% to 90% by weight of an aqueous carrier, based on the weight of the aqueous adhesive composition. The aqueous adhesive composition may also contain 0.5% to 8% by weight of a polyvinyl alcohol crosslinking agent, excluding solvent, based on the weight of the aqueous adhesive composition. The aqueous adhesive composition may also contain 0.3% to 2% by weight of a light absorber, excluding solvent, based on the weight of the aqueous adhesive composition. The aqueous adhesive composition may also contain 0.1% to 0.8% by weight of a light stabilizer, excluding solvent, based on the weight of the aqueous adhesive composition. The light stabilizer may be a hindered amine light stabilizer (HALS).

[0108] This polyurethane is typically prepared via a polyaddition process involving diisocyanates. Non-limiting examples of polyurethanes include polyether polyurethanes, polyester polyurethanes, polycarbonate polyurethanes, polyether polyurea, polyurea, polyester polyurea, polyester polyurea, polyisocyanates (such as polyurethanes containing isocyanate bonds), and polycarbodiimides (such as polyurethanes containing carbodiimide bonds). Typically, this polyurethane contains carbamate groups. The polyurethane used in the aqueous adhesive composition can be prepared using methods known in the art. Preferably, the polyurethane in the aqueous adhesive composition of the present invention can be a polyether polyester polyurethane, a polycarbonate polyurethane, or mixtures thereof. In one example, the polyurethane in the aqueous adhesive composition is an aliphatic polycarbonate polyurethane. In another example, the polyurethane in the aqueous adhesive composition is an aqueous dispersion. The polyurethane can be a crosslinked polyurethane or a non-crosslinked polyurethane. The aqueous adhesive composition may contain 30% to 80% by weight, or 40% to 65% by weight, or 45% to 60% by weight of polyurethane excluding solvents. The polyurethane can have a number average molecular weight of 1,000 to 2,000,000 Daltons, 5,000 to 1,500,000 Daltons, 10,000 to 1,000,000 Daltons, or 30,000 to 800,000 Daltons. Non-limiting examples of commercially available polyurethanes that can be used in waterborne adhesive compositions include Relca® PU-406 from Stahl Polymers, Alberdingk® U6150 from Alberdingk® Boley, Alberdingk U400N from Alberdingk® Boley, HD2125 from Hauthaway, Witcobond® W-281F from Chemtura Corp., and Dispercoll® U53 from Covesto.

[0109] Self-crosslinking polymers contain functional groups that enable reactions between polymer chains (same or different polymer molecules) without the need for separate reactants. These self-crosslinking polymers are typically in the form of aqueous dispersions or emulsions and are usually the product of the reaction of at least two monomers. For example, such polymers may contain carbonyl and amine functional groups, or epoxy and hydroxyl, amine, or carboxyl functional groups. Self-crosslinking acrylic polymers can be formed from one or more acrylic monomers, such as, for example, methacrylates, methyl methacrylate, butyl acrylate, butyl methacrylate, styrene, and methylstyrene.

[0110] The aqueous adhesive composition may contain a self-crosslinking acrylic polymer and polyvinyl alcohol in a weight ratio of 0.15 to 0.30, 0.18 to 0.28, or 0.19 to 0.27.

[0111] The polyvinyl alcohol in this aqueous adhesive composition contains acetyl-acetyl functional groups in its molecular structure. The polyvinyl alcohol may have a number average molecular weight of 1,000 to 1,000,000 Daltons. The polyvinyl alcohol may have a degree of hydrolysis of 90% to 99%, or 91% to 98%, or 92% to 96%. The aqueous adhesive composition may contain 30% to 80% by weight, or 40% to 65% by weight, or 45% to 60% by weight of polyvinyl alcohol, excluding solvents, based on the weight of the aqueous adhesive composition.

[0112] An example of polyvinyl alcohol containing acetylacetonate functional groups in its molecular structure is GOHSENX™ Z-410, supplied by Mitsubishi Chemical. This material is crosslinkable and can be crosslinked by heat treatment or by exposure to UV radiation. Other commercially available examples of polyvinyl alcohol containing acetylacetonate functional groups in their molecular structure include GOHSENX™ Z-100, GOHSENX™ Z-200, GOHSENX™ Z-205, GOHSENX™ Z-210, GOHSENX™ Z-220, GOHSENX™ Z-300, and GOHSENX™ Z-320. The polyvinyl alcohol can be a copolymer formed by the polymerization of vinyl alcohol and acetylacetonate. The polyvinyl alcohol can also be a trimer formed by the polymerization of vinyl alcohol, vinyl acetate, and acetylacetonate.

[0113] The aqueous adhesive composition may contain polyvinyl alcohol and polyurethane in weight ratios of 4 to 0.4, 3 to 0.3, 2 to 0.2, 1.5 to 0.7, 1.3 to 0.8, 1.2 to 0.85, or 1.1 to 0.9.

[0114] The aqueous adhesive composition may include: 0.5% to 8% by weight of polyvinyl alcohol crosslinking agent, excluding solvent, based on the weight of the aqueous adhesive composition; and 0.2% to 8%, 0.3% to 6%, 0.4% to 5%, 0.5% to 4%, and 0.8% to 3% by weight of polyvinyl alcohol crosslinking agent, excluding solvent, based on the weight of the aqueous adhesive composition. The crosslinked polyvinyl alcohol in the adhesive layer is formed by the reaction of polyvinyl alcohol with the crosslinking agent. Therefore, the aqueous adhesive composition includes polyvinyl alcohol and a crosslinking agent. The crosslinking agent reacts with polyvinyl alcohol at the hydroxyl or acetoacetyl functional groups of the polyvinyl alcohol. That is, the crosslinking agent reacts with two or more polyvinyl alcohol polymer molecules to form bonds between the polymers. The crosslinking agent has two or more reactive functional groups, such as alcohols, amines, and aldehydes. Non-limiting typical examples of crosslinking agents include diamines, polyamines, diols, polyols, dialdehydes, diacetic acid hydrazides, organotitanates, organozirconates, and organoborates. The crosslinking agent can be a saturated dialdehyde having 2 to 6 carbon atoms, such as glyoxal.

[0115] The adhesive layer quality requirement of the electro-optic device of the present invention requires that the adhesive film of the intermediate electro-optic laminate includes polyvinyl alcohol, wherein the acetyl-acetyl functional groups are not all cross-linked. That is, even if the aqueous adhesive composition contains a cross-linking agent that allows cross-linking of polyvinyl alcohol through acetyl-acetyl functional groups, the polyvinyl alcohol of the adhesive film of the intermediate electro-optic laminate must still have uncross-linked acetyl-acetyl functional groups. Of course, if the aqueous adhesive composition does not contain such a cross-linking agent, then the polyvinyl alcohol of the adhesive film contains acetyl-acetyl functional groups. Therefore, in the case where the aqueous adhesive composition contains a cross-linking agent, the stoichiometry of the aqueous adhesive composition must be controlled so that after the polyvinyl alcohol cross-links to form an adhesive film, the cross-linked polyvinyl alcohol of the adhesive film of the intermediate electro-optic laminate still retains acetyl-acetyl functional groups. These acetyl acetyl functional groups ultimately need to react with the polar groups on the surface of the thermoplastic film of the second substrate layer to form an adhesive between the first adhesive layer and the thermoplastic film.

[0116] The aqueous adhesive composition must be a fluid with appropriate viscosity to be successfully applied to the second electrode layer to form the adhesive film of the intermediate electro-optic laminate. Rheology modifiers may be used to adjust the viscosity of the aqueous adhesive composition. Furthermore, the aqueous adhesive composition must have a sufficiently long shelf life. In some cases, polyvinyl alcohol crosslinking agents, self-crosslinking acrylic resins, or other components in the aqueous adhesive composition may increase its viscosity to a level that prevents its application to the second electrode layer to form the adhesive film of the intermediate electro-optic laminate. Therefore, the aqueous adhesive composition must be formulated with care to ensure a sufficiently long shelf life. The crosslinking agent may have a shelf life exceeding 1 day, 3 days, 5 days, or 7 days. Non-limiting examples of polyvinyl alcohol crosslinkers that can provide long-life water-based adhesive compositions include Safelink™ SPM-01 from Mitsubishi Chemical and glyoxal and organic zirconates such as ZrO(OH)Cl*nH2O (provided by Daiichi Kigenso Kagaku Kogyo Co., Ltd with ZIRCOZOL ZC-2) and (NH4)2ZrO(CO3)2 (provided by Daiichi Kigenso Kagaku Kogyo Co., Ltd with ZIRCOZOL AC-7).

[0117] Second substrate layer

[0118] The second substrate layer of the chemically resistant electro-optic device of the present invention is formed of a thermoplastic film. The thermoplastic film used to form the second substrate layer may contain a thermoplastic resin selected from the group consisting of polyethylene, polypropylene, polybutene, polyethylene terephthalate, ethylene copolymers, propylene copolymers, butene copolymers, and mixtures thereof.

[0119] The second substrate layer must protect the optoelectronic element from mechanical damage and prevent moisture and other materials from diffusing into the device. To manufacture a chemically resistant device, the second substrate layer must be strongly bonded to the adhesive layer. The inventors of this invention have discovered that a strong bond can be achieved between the second electrode and the second substrate layer via an adhesive layer, wherein the thermoplastic film of the second substrate layer is surface-treated to include polar groups. These polar groups can form covalent bonds with the acetyl-acetyl functional groups of the polyvinyl alcohol in the adhesive layer. Therefore, the adhesive layer formed by crosslinking polyvinyl alcohol with a crosslinking agent should contain non-crosslinked acetyl-acetyl functional groups. In other words, the crosslinking of the polyvinyl alcohol should be partial.

[0120] Numerous methods are available for surface treatment of thermoplastic films containing thermoplastic resins, such as polyethylene, polypropylene, polybutene, ethylene copolymers, propylene copolymers, and butene copolymers. Non-limiting examples of these methods include corona treatment, flame treatment, plasma treatment, and chemical treatments, such as ozone treatment.

[0121] The electrophoretic display of the present invention may include a piezoelectric material layer comprising a piezoelectric material. This electrophoretic display can operate without a power supply. This simplifies the structure of the electrophoretic display. The piezoelectric material layer may be disposed between (a) the electro-optic material layer and the first transparent electrode layer, (b) the electro-optic material layer and the second electrode layer, or (c) side-by-side with the electro-optic material layer.

[0122] Piezoelectricity is the accumulation of electrical charge in a solid material (piezoelectric material) in response to applied mechanical stress. Examples of piezoelectric materials include polyvinylidene fluoride (PVDF), quartz (SiO2), aluminosilicate (AlPO4), gallium orthophosphate (GaPO4), tourmaline, barium titanate (BaTiO3), lead zirconate titanate (PZT), zinc oxide (ZnO), aluminum nitride (AlN), lithium tantalate, lanthanum gallium silicate, sodium potassium tartrate, and any other known piezoelectric material. The piezoelectric material may further comprise ionic liquids.

[0123] When viewed from the viewing side of the display, the voltage generated by piezoelectricity can drive the pigments in the electrophoretic material layer to change the color or image of the electrophoretic material. For example, a voltage can be generated by bending or by introducing stress into an electro-optic display containing a piezoelectric material layer, and this voltage can be used to cause the color pigments in the electrophoretic material to move.

[0124] Figure 10A shows an example of an electro-optic component including a piezoelectric material layer. Figure 10A is a cross-sectional view of component 1000A, which includes a piezoelectric material layer 1002 capable of driving an electro-optic material layer 260. The electro-optic component includes a first substrate layer 211, a first transparent electrode layer 210, an electro-optic material layer 260, a piezoelectric material layer 1002, and a second electrode layer 250. The piezoelectric material layer 1002 is located between the second electrode layer 250 and the electro-optic material layer 260, while the electro-optic material layer 260 is disposed between the first transparent electrode layer 210 and the piezoelectric material layer 1002. The electro-optic material layer 260 may include a plurality of microcells (not shown in Figure 10A), each of the plurality of microcells including a microcell base, a microcell wall, and a microcell opening, and containing an electrophoretic medium. A sealing layer (not shown in Figure 10A) spans the microcell openings of the plurality of microcells. The sealing layer may be located adjacent to the piezoelectric layer 1002. The first transparent electrode layer 210 may have the form of a single continuous electrode (also called a conductive layer), and the second electrode layer 250 may include multiple pixel electrodes (pixel electrode matrix). The electro-optic component 1000A can be used to fabricate an electro-optic device (1000B) by applying an aqueous adhesive composition to the second electrode layer (250) of the present invention, curing the aqueous adhesive composition to form an adhesive film, and then attaching a thermoplastic film to the adhesive film by hot stamping to form a chemically resistant electro-optic device 1000B, as shown in FIG10B. The chemically resistant electro-optic device 1000B of FIG10B includes a first substrate layer 211, a first transparent electrode layer 210, an electro-optic material layer 260, a piezoelectric material layer 1002, a second electrode layer 250, a first adhesive layer 240, and a second substrate layer 212. The user can bend the display to generate a voltage sufficient to operate the display.

[0125] Figure 11A illustrates a cross-sectional view of another example of an electro-optic component 1100A, which includes a piezoelectric material layer 1002 capable of driving an electro-optic material layer 260. The electro-optic component includes a first substrate layer 211, a first transparent electrode layer 210, a piezoelectric material layer 1002, an electro-optic material layer 260, and a second electrode layer 250. The piezoelectric material layer 1002 is located between the first transparent electrode layer 210 and the electro-optic material layer 260, while the electro-optic material layer 260 is disposed between the second electrode layer 250 and the piezoelectric material layer 1002. The electro-optic material layer 260 may include a plurality of microcells (not shown in Figure 11A), each microcell including a microcell base, a microcell wall, and a microcell opening, and containing an electrophoretic medium. A sealing layer (not shown in Figure 11A) spans the microcell openings of the plurality of microcells. The sealing layer may be located adjacent to the second electrode layer 250. The electro-optic component may further include an adhesive layer (not shown in FIG11A) disposed between the electro-optic material layer 260 and the second electrode layer 250. The first light-transmitting electrode layer 210 may have the form of a single continuous electrode (also referred to as a conductive layer), and the second electrode layer 250 may include multiple pixel electrodes (pixel electrode matrix). The electro-optic component 1100A can be used to fabricate a chemically resistant electro-optic device (1100B) by applying an aqueous adhesive composition to the second electrode layer (250) of the present invention, curing the aqueous adhesive composition to form an intermediate electro-optic laminate including an adhesive film, and attaching a thermoplastic film to the adhesive film of the intermediate electro-optic laminate by hot stamping. The chemically resistant electro-optic device 1100B of FIG11B includes a first substrate layer 211, a first light-transmitting electrode layer 210, a piezoelectric material layer 1002, an electro-optic material layer 260, a second electrode layer 250, a first adhesive layer 240, and a second substrate layer 212. Users can bend the display to generate enough voltage to power it.

[0126] Figure 12 illustrates a cross-sectional view of an example electro-optic component 1200, which includes (1) a piezoelectric material layer 1002 capable of driving an electro-optic material layer 260 and (2) a sealing layer. The electro-optic component includes a first transparent electrode layer 210, an electro-optic material layer 260, a piezoelectric material layer 1002, and a second electrode layer 250. In this embodiment, the piezoelectric material layer 1002 is disposed between the electro-optic material layer and the second electrode layer 250. The piezoelectric material layer 1002 overlaps only with a first portion of the electrophoretic material layer 260. The second electrode layer 250 overlaps with all piezoelectric material layers 1002 and a second portion of the electro-optic material layer, wherein the second portion of the electro-optic material layer does not overlap with the piezoelectric material layer 1002. The first portion of the electro-optic material layer may contain a first plurality of microcells (not shown in Figure 12) and may have a first resistance, while the second portion of the electro-optic material layer may contain a second plurality of microcells (not shown in Figure 12) and may have a second resistance. The first transparent electrode layer 210 is adjacent to the electro-optic material layer 260 and on the opposite side of the piezoelectric material layer 1002 and the second electrode layer 250, as illustrated in FIG12. Each of the first and second plurality of microcells includes a microcell base, a microcell wall, and a microcell opening, and contains an electrophoretic medium. A sealing layer (not shown in FIG12) spans the microcell openings of the first and second plurality of microcells. This sealing layer may be located adjacent to the piezoelectric material layer 1002 and the second electrode layer 250 (on the side of the electro-optic material layer opposite to the first transparent electrode layer 210). The electro-optic component 1200 can be used to fabricate a chemically resistant electro-optic device by applying an aqueous adhesive composition to the second electrode layer of the present invention, curing the aqueous adhesive composition, and attaching a thermoplastic film by hot stamping.

[0127] In another example, the piezoelectric material layer 1002 may be laminated onto a semiconductor or high-resistivity layer 1312, and then the semiconductor or high-resistivity layer 1312 may be laminated onto a first transparent electrode layer 210, as shown in FIG13, instead of directly laminating the piezoelectric material layer onto or overlapping the electro-optic material layer as shown in FIG10A, 11A, and 12. In this configuration, the electro-optic component 1300 includes a semiconductor or high-resistivity layer 1312. The semiconductor or high-resistivity layer 1312 replaces the electro-optic material layer 260 at the top portion of the piezoelectric material layer 1002, thereby reducing the overall thickness of the display and preventing rapid dissipation of charge on the piezoelectric material layer 1002. Therefore, locally generated charge (generated through the piezoelectric material layer 1002) can be effectively and efficiently applied to the electro-optic material layer 260. This improves the contrast of the display. The first transparent electrode layer 210 and the second electrode layer 250 sandwich an electro-optic material layer 260, a semiconductor or high-resistivity layer 1312, and a piezoelectric material layer 1002, as shown in FIG13. The electro-optic material layer 260 may contain multiple microcells (not shown in FIG13), each of the multiple microcells including a microcell base, a microcell wall, and a microcell opening, and containing an electrophoretic medium. A sealing layer (not shown in FIG13) may span the microcell openings of the multiple microcells. The sealing layer (not shown in FIG13) may be located adjacent to the first transparent electrode layer 210. The sealing layer (not shown in FIG13) may be located adjacent to the second electrode layer 250. The electro-optic component 1300 can be used to prepare a chemically resistant electro-optic device by applying an aqueous adhesive composition to the second electrode layer (250) of the present invention, curing the aqueous adhesive composition, and attaching a thermoplastic film by hot stamping.

[0128] In another example, Figure 14 illustrates a cross-sectional view of an electro-optic assembly 1400, which includes a piezoelectric layer and a sealing layer. The assembly 1400 differs from the assembly illustrated in Figure 13 in that only a portion of the piezoelectric material layer 1002 overlaps with the first light-transmitting electrode layer 210. In this configuration, the piezoelectric material layer 1002 is avoided from being placed in a neutral plane position, allowing for better image generation from the piezoelectric material layer 1002. Furthermore, the piezoelectric material layer 1002 may be a metallized piezoelectric material layer and may be covered by a metal layer 1413. In some examples, a first semiconductor layer 1312 may be disposed between the metal layer 1413 and the first light-transmitting electrode layer 210. Another semiconductor layer, a second semiconductor layer 1410, may be disposed between the piezoelectric material layer 1002 and the second electrode layer 250. It should be understood that all layers described herein, including the first light-transmitting electrode layer 210 and the second electrode layer 250, may be light-transmitting, allowing the final device to be viewed from any direction or orientation. The electro-optic material layer 260 may comprise a plurality of microcells (not shown in FIG. 14), each of the plurality of microcells including a microcell base, a microcell wall, and a microcell opening, and containing an electrophoretic medium. A sealing layer (not shown in FIG. 14) spans the microcell openings of the plurality of microcells. This sealing layer (not shown in FIG. 14) may be located adjacent to the second electrode layer 250. This sealing layer (not shown in FIG. 14) may be located adjacent to the second semiconductor layer 1410. The electro-optic component 1400 can be used to fabricate a chemically resistant electro-optic device by applying an aqueous adhesive composition to the second electrode layer of the present invention, curing the aqueous adhesive composition, and attaching a thermoplastic film by hot stamping.

[0129] Figure 15 illustrates a cross-sectional view of another example of an electro-optic assembly 1500. The electro-optic assembly 1500 includes a piezoelectric material layer and a sealing layer. As shown in Figure 15, the electro-optic material layer 260 may partially extend below the piezoelectric material layer 1002 to overlap it, ensuring a robust connection with the piezoelectric material layer 1002. In this example, the electro-optic display layer 260 may have: a portion having microcells 807, and another generally flat portion 1515 configured to establish a connection with the piezoelectric material layer 1002. In this configuration, the piezoelectric material layer 1002 is arranged to overlap the generally flat portion 1515 to ensure a good connection with the electro-optic material layer 260. This configuration advantageously establishes a strong connection between the piezoelectric material layer 1002 and the electro-optic material layer 260. For example, this configuration provides a robust connection between the piezoelectric material layer 1002 and the electro-optic material layer 260 capable of withstanding repeated bending or stress applied to the electro-optic display 1500. Furthermore, a first adhesive layer 240 may be disposed between the piezoelectric material layer 1002 and the first transparent electrode layer 210. Each microcell 807 includes a microcell opening, and a sealing layer 230 spans each microcell opening. Additionally, a second electrode layer 250 is adjacent to the electro-optic material layer 260. The electro-optic component 1500 can be used to fabricate a chemically resistant electro-optic device by applying an aqueous adhesive composition to the second electrode layer of the present invention, curing the aqueous adhesive composition, and attaching a thermoplastic film by hot stamping. Example

[0130] [Preparation of an electro-optic sheet:] An electro-optic sheet is prepared, which sequentially comprises a first substrate layer, a first transparent electrode layer, a first transparent electrode layer comprising indium tin oxide, an electro-optic material layer, and a second electrode layer comprising poly(3,4-ethyldioxythiophene) polystyrene sulfonate (a conductive polymer). The electro-optic material layer comprises a plurality of microcells. Each microcell comprises a microcell base, a microcell wall, a microcell opening, and a sealing layer. The sealing layer spans the microcell opening. The sealing layer is in contact with the second electrode layer. Figure 3A illustrates a side view of the electro-optic sheet.

[0131] [Preparation of Aqueous Adhesive Compositions:] Aqueous adhesive compositions are prepared by mixing the components of an aqueous adhesive composition. Tables 1 and 2 provide aqueous adhesive compositions. The content of the aqueous adhesive compositions in Table 1 represents the weight of the active material. That is, the composition does not include the solvent.

[0132] [Preparation of the intermediate electro-optic laminate:] Each aqueous adhesive composition was coated onto the second electrode layer of the separated electro-optic sheet and exposed to a temperature of 80°C to 100°C for 3 hours to cure into an aqueous adhesive composition, forming an adhesive film on the second electrode and thus forming an intermediate electro-optic laminate. The adhesive layer of this intermediate electro-optic laminate is non-adhesive, and the intermediate electro-optic laminate can be rolled into a web. Figure 4A illustrates a side view of the intermediate electro-optic laminate.

[0133] [Preparation of the electro-optic device:] The adhesive layers of each prepared intermediate electro-optic laminate are aligned with a thermoplastic film and exposed to a hot stamping machine at 95°C and a pressure of 1 MPa to 50 MPa for 0.5 seconds to form the electro-optic device. The thermoplastic film comprises polypropylene, which is surface-treated to form polar groups on the surface of the thermoplastic film. The adhesive strength of the first adhesive layer of the device is described below. Figure 2A illustrates a side view of the intermediate electro-optic laminate.

[0134] evaluate.

[0135] The shelf life of this water-based adhesive composition was evaluated at 25°C. This shelf life is evaluated based on the time during which the water-based adhesive composition can still be applied to a surface.

[0136] The chemical resistance of the electro-optic device was evaluated by immersing the device in a solvent or aqueous solution for a specific time and then assessing the adhesive strength of the adhesive layer. Specifically, the chemical resistance of the electro-optic device was assessed by: (a) immersing the device in toluene at room temperature for 5 hours; (b) immersing the device in ethanol at room temperature for 5 hours; (c) immersing the device in acetone at room temperature for 5 hours; (d) immersing the device in water at 100°C for 30 minutes; (e) immersing the device in water at 100°C for 2 hours; (f) immersing the device in 0.1M HCl at 25°C for 2 hours; (g) immersing the device in 0.1M acetic acid solution at 25°C for 2 hours; and (h) immersing the device in 0.1M NH4OH solution at 25°C for 4 hours.

[0137] According to the method of ASTM D093, the force required to separate the adhesive layer at a 180° angle is measured at a speed of 5 mm / s to evaluate the anti-adhesion of the adhesive layer on the second electrode.

[0138] Table 1: Waterborne adhesive compositions containing polyurethane, polyvinyl alcohol, and crosslinking agents. The content of each component in this waterborne adhesive composition is expressed as a percentage by weight of the active material, excluding water and other solvents. The weight percentage content of the components does not include solvents (including water) in the raw materials. content Element Ex1 Ex2 Ex3 Polyurethane dispersions [1] 48.0 48.0 Polyurethane dispersions [2] 48.0 Polyvinyl alcohol containing reactive acetyl-acetyl functional groups [3] 48.0 48.0 Polyvinyl alcohol containing reactive acetyl-acetyl functional groups [4] 48.0 Crosslinking agents for crosslinked polyvinyl alcohol [5] 3.0 3.0 3.0 Water-based ultraviolet absorbers [6] 0.5 0.5 0.5 Hindered amine light stabilizers (HALS)[7] 0.5 0.5 0.5 Water and other solvents

[15] QS QS QS Adhesion strength of the adhesive layer on the thermoplastic polymer of the final electro-optic device (unit: N / in) Higher than 16 Higher than 16 Higher than 16 [1]Alberdingk® U6150, an aliphatic carbonate polyurethane aqueous dispersion, supplied by Alberdingk Boley. [2] Relca PU-406, an aliphatic carbonate polyurethane aqueous dispersion, supplied by Stahl. [3]GOHSENX™ Z320, provided by Mitsubishi Chemical. [4] GOHSENX™ Z410, provided by Mitsubishi Chemical. [5] Safelink™ SPM-01 glyoxylate, supplied by Mitsubishi Chemical; the stoichiometry of this crosslinking agent allows polyvinyl alcohol to be partially crosslinked during the intermediate electro-optic lamination stage. [6], [7] EVERSORB® AQ1 contains UV absorbers and HALS.

[15] Small amounts of organic solvents may be present as impurities and / or as part of the component carrier provided by the manufacturer.

[0139] Table 1 shows the aqueous adhesive composition, which includes (a) polyvinyl alcohol with acetyl-acetyl functional groups, (b) polyurethane, and (c) a crosslinking agent (for polyvinyl alcohol). The stoichiometry of this aqueous adhesive composition enables the formation of an intermediate electro-optic laminate containing partially crosslinked polyvinyl alcohol, and an electro-optic device with strong adhesion between the second substrate layer (whose surface contains polar functional groups) and the first adhesive layer, and between the second electrode layer (containing poly(3,4-ethyldioxythiophene)polystyrene sulfonate) and the first adhesive layer. Furthermore, since the adhesive film of the intermediate electro-optic laminate is non-adhesive, the intermediate electro-optic laminate can be stored as a web. It has been observed that if the adhesive film of the intermediate electro-optic laminate contains fully crosslinked polyvinyl alcohol, the final electro-optic device has a deficient characteristic: the adhesion strength between the first adhesive layer and the second substrate layer is weak.

[0140] Table 2: Waterborne adhesive compositions containing polyurethane and polyvinyl alcohol, but without crosslinking agents and chemically resistant in organic solvents. The content of each component in this waterborne adhesive composition is expressed as a percentage by weight of the active material, excluding water and other solvents. The weight percentage content of the components does not include solvents (including water) in the raw materials. Element Ex4 Ex5 Ex6 Ex7 Polyurethane dispersions [8] 48.0 48.0 Polyurethane dispersions [1] 48.0 Self-crosslinking acrylic polymers[9] 18.0 Self-crosslinking acrylic polymers

[10] Polyurethane mixtures

[11] Styrene-butadiene copolymer

[12] Polyvinyl alcohol containing reactive acetyl-acetyl functional groups [3] 48.0 48.0 78.0 Polyvinyl alcohol containing reactive acetyl-acetyl functional groups [4] 48.0 Rheology modifiers

[13] 2.0 2.0 2.0 2.0 Water-based ultraviolet absorbers [6] 1.5 1.5 1.5 1.5 Hindered amine light stabilizers (HALS)[7] 0.5 0.5 0.5 0.5 Water and solvents

[15] QS QS QS QS Adhesion strength of the adhesive layer on the imprinted substrate (unit: N / in) Higher than 16 Higher than 16 Higher than 16 Higher than 16 Adhesive strength of the adhesive layer after immersion in toluene at 25°C for 5 hours (unit: N / in) Higher than 16 Higher than 16 Higher than 16 Higher than 16 Adhesive strength of the adhesive layer after immersion in ethanol at 25°C for 5 hours (unit: N / in) Higher than 16 Higher than 16 Higher than 16 Higher than 16 Adhesive strength of the adhesive layer after immersion in acetone at 25°C for 5 hours (unit: N / in) Higher than 16 Higher than 16 Higher than 16 Higher than 16 Element Ex8 Compare Ex.9 Compare Ex.10 Polyurethane dispersions [9] Polyurethane dispersions [1] Self-crosslinking acrylic polymers

[10] Self-crosslinking acrylic polymers

[11] 18 Polyurethane mixtures

[12] 96 Styrene-butadiene copolymer

[13] 96 Polyvinyl alcohol containing reactive acetyl-acetyl functional groups [3] 78 Polyvinyl alcohol containing reactive acetyl-acetyl functional groups [4] Rheology modifiers

[13] 2 2 2 Water-based ultraviolet absorbers [6] 1.5 1.5 1.5 Hindered amine light stabilizers (HALS)[7] 0.5 0.5 0.5 Water and other solvents

[15] QS QS QS Adhesion strength of the adhesive layer on the imprinted substrate (unit: N / in) Higher than 16 4 4 Adhesive strength of the adhesive layer after immersion in toluene at 25°C for 5 hours (unit: N / in) Higher than 16 Less than 1 Less than 1 Adhesive strength of the adhesive layer after immersion in ethanol at 25°C for 5 hours (unit: N / in) Higher than 16 4 4 Adhesive strength of the adhesive layer after immersion in acetone at 25°C for 5 hours (unit: N / in) Higher than 16 Less than 1 Less than 1 [1]Alberdingk® U6150, supplied by Alberdingk Boley. [3]GOHSENX™ Z320, provided by Mitsubishi Chemical. [4] GOHSENX™ Z410, provided by Mitsubishi Chemical. [6], [7] EVERSORB® AQ1 contains UV absorbers and HALS. [8]Alberdingk® U6100, provided by Alberdingk Boley. [9]Alberdingk® AC3600, provided by Alberdingk Boley.

[10] Alberdingk® AC3660, supplied by Alberdingk Boley.

[11] HS4305, provided by Henkel.

[12] F9022N, provided by Henkel.

[13] Hydrophobically modified alkali-soluble acrylic emulsion (HASE); Solthix A100, Lubrizol.

[15] Small amounts of organic solvents may be present as impurities and / or as part of the component carrier provided by the manufacturer.

[0141] Table 2 shows the first adhesive layer of the electro-optic device of the present invention formed from the aqueous adhesive composition (Ex.4 to Ex.8) of the present invention, which has higher adhesive strength than the comparative electro-optic device under various conditions. The aqueous adhesive composition of the present invention comprises (i) a combination of polyurethane or self-crosslinking acrylic polymer and polyvinyl alcohol containing acetyl-acetyl functional groups.

[0142] Table 3: Comparison of the curing service life and adhesion strength of the electro-optic device of the present invention after immersion in an aqueous solution. Condition Ex4 Ex5 Ex6 Immerse in water at 100°C for 30 minutes (unit: N / in) 6 6 Less than 1 Immerse in water at 100°C for 2 hours (unit: N / in) Less than 1 Less than 1 Less than 1 Immerse in 0.1M HCl solution at 25°C for 2 hours (unit: N / in) Higher than 16 Higher than 16 Higher than 16 Immerse in 0.1M acetic acid solution at 25°C for 4 hours (unit: N / in). Higher than 16 3 Less than 1 Immerse in 0.1M NaOH solution at 25°C for 2 hours (unit: N / in) Higher than 16 Higher than 16 Higher than 16 Immerse in 0.1M NH4OH solution at 25°C for 4 hours (unit: N / in) Higher than 16 3 Less than 1 Immerse in toluene solution at 25°C for 5 hours (unit: N / in) Higher than 16 Higher than 16 Higher than 16 Immerse in ethanol solution at 25°C for 5 hours (unit: N / in) Higher than 16 Higher than 16 Higher than 16 Immerse in acetone solution at 25°C for 5 hours (unit: N / in) Higher than 16 Higher than 16 Higher than 16 Usage period (days) 180 180 180 Condition Ex7 Ex8 Immerse in water at 100°C for 30 minutes (unit: N / in) Higher than 16 Higher than 16 Immerse in water at 100°C for 2 hours (unit: N / in) Higher than 16 Higher than 16 Immerse in 0.1M HCl solution at 25°C for 2 hours (unit: N / in) Higher than 16 Higher than 16 Immerse in 0.1M acetic acid solution at 25°C for 4 hours (unit: N / in). Higher than 16 Higher than 16 Immerse in 0.1M NaOH solution at 25°C for 2 hours (unit: N / in) Higher than 16 Higher than 16 Immerse in 0.1M NH4OH solution at 25°C for 4 hours (unit: N / in) Higher than 16 Higher than 16 Immerse in toluene solution at 25°C for 5 hours (unit: N / in) Higher than 16 Higher than 16 Immerse in ethanol solution at 25°C for 5 hours (unit: N / in) Higher than 16 Higher than 16 Immerse in acetone solution at 25°C for 5 hours (unit: N / in) Higher than 16 Higher than 16 Usage period (days) 30 30

[0143] Table 3 shows that, compared to the electro-optic device of the present invention having a first adhesive layer composed of a combination of polyurethane and polyvinyl alcohol, the electro-optic device of the present invention having improved water resistance. It was also observed that when the weight ratio of the self-crosslinking acrylic polymer to polyvinyl alcohol was 0.15 to 0.30, the adhesive strength of the first adhesive layer (to the second substrate layer and the second electrode layer) was higher. Furthermore, the water-based adhesive composition of the present invention has an acceptablely long shelf life.

[0144] Table 4: Waterborne adhesive compositions containing polyvinyl alcohol with active acetyl functional groups and polyurethanes with various conversion temperatures. Element Ex4 Ex6 Ex.11 Polyurethane dispersions [8] 48 Polyurethane dispersions [1] 48 Polyurethane dispersions

[14] 48 Polyvinyl alcohol containing reactive acetyl-acetyl functional groups [3] 48 48 48 Rheology modifiers [9] 2.0 2.0 2.0 Water-based ultraviolet absorbers [6] 1.5 1.5 1.5 Hindered amine light stabilizers (HALS)[7] 0.5 0.5 0.5 Water and other solvents

[15] QS QS QS Glass transition temperature of polyurethane (unit: °C) Below -40 Below 0 Below 25 The required hot stamping temperature (degrees Celsius) is applied for 0.5 seconds to achieve 16 N / in. or greater adhesive strength 80-90 90-100 100-110 [1]Alberdingk® U6150, supplied by Alberdingk Boley. [3]GOHSENX™ Z320, provided by Mitsubishi Chemical. [8]Alberdingk® U6100, provided by Alberdingk Boley. [6], [7] EVERSORB® AQ1 contains UV absorbers and HALS. [9] Hydrophobically modified alkali-soluble acrylic emulsion (HASE); Solthix A100, Lubrizol.

[14] Alberdingk® U9190, provided by Alberdingk Boley.

[15] Small amounts of organic solvents may be present as impurities and / or as part of the component carrier provided by the manufacturer. Table 4 shows that when the glass transition temperature (Tg) of the polyurethane in the first adhesive layer is -30°C or lower, the hot stamping temperature required to achieve a very strong adhesion layer for the first adhesive layer is lower. That is, a lower Tg is beneficial to the hot stamping process steps.

[0145] Terms and Conditions

[0146] Clause 1: A chemically resistant multilayer electro-optic device, comprising, in sequence: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, a first adhesive layer, and a second substrate layer, wherein the first adhesive layer comprises: 20 to 80% by weight of polyurethane, cross-linked acrylic polymer, or a mixture of polyurethane and cross-linked acrylic polymer, excluding solvent, based on the weight of the first adhesive layer; and 20 to 80% by weight of polyvinyl alcohol, excluding solvent, based on the weight of the first adhesive layer, wherein the polyvinyl alcohol contains acetyl-acetyl functional groups in its molecular structure; the second substrate layer is formed using a thermoplastic film having a surface, the thermoplastic film comprising a thermoplastic resin, the thermoplastic film having a surface treatment such that the surface of the thermoplastic film contains polar functional groups, wherein at least a portion of the polar functional groups are covalently bonded to the polyvinyl alcohol of the first adhesive layer, the covalent bond being formed by the reaction of the acetyl-acetyl functional groups of the polyvinyl alcohol with the polar functional groups on the surface of the thermoplastic film.

[0147] Clause 2: The chemical-resistant multilayer electro-optic device of Clause 1, wherein the electro-optic material layer comprises an electrophoretic medium comprising charged pigment particles, a charge control agent and a nonpolar liquid, the electrophoretic medium being encapsulated in multiple microcells or multiple microcapsules.

[0148] Clause 3: As in Clause 2, the chemical-resistant multilayer electro-optic device, wherein each of the plurality of microcells comprises a microcell base layer, a microcell wall, a microcell opening and a sealing layer, the sealing layer spanning the microcell opening and contacting the second electrode layer.

[0149] Clause 4: A chemically resistant multilayer electro-optic device as described in any of Clauses 1 to 3, wherein the second electrode layer comprises a conductive polymer.

[0150] Clause 5: Chemically resistant multilayer electro-optic devices as described in Clause 4, wherein the conductive polymer is selected from the group consisting of poly(3,4-ethyldioxythiophene): polystyrene sulfonate (PEDOT-PSS), polyacetylene, polyphenylene sulfide, polystyrene, and combinations thereof.

[0151] Clause 6: A chemically resistant multilayer electro-optic device as described in any of Clauses 1 to 5, wherein the thermoplastic film used to form the second substrate layer comprises a thermoplastic resin selected from the group consisting of polyethylene, polypropylene, polybutene, polyethylene terephthalate, ethylene copolymers, propylene copolymers, butene copolymers, and mixtures thereof.

[0152] Clause 7: A chemically resistant multilayer electro-optic device as described in any of Clauses 1 to 6, wherein the first adhesive layer comprises polyurethane or a mixture of polyurethane and crosslinked acrylic polymer, and wherein the glass transition temperature of the polyurethane is below -30°C.

[0153] Clause 8: A chemically resistant multilayer electro-optic device as described in any of Clauses 1 to 7, wherein the first adhesive layer comprises polyurethane or a mixture of polyurethane and crosslinked acrylic polymer, and wherein the polyurethane is crosslinked.

[0154] Clause 9: A chemically resistant multilayer electro-optic device as described in any of Clauses 1 to 8, wherein the polyvinyl alcohol is cross-linked, and the cross-linked polyvinyl alcohol is formed by reacting polyvinyl alcohol with a cross-linking agent.

[0155] Clause 10: Chemically resistant multilayer electro-optic devices as described in Clause 9, wherein the crosslinking agent is selected from the group consisting of dialdehyde, diamine and organozirconate.

[0156] Clause 11: A chemically resistant multilayer electro-optic device as described in any of Clauses 1 to 10, wherein the degree of hydrolysis of the polyvinyl alcohol is 90% to 99%.

[0157] Clause 12: A chemically resistant multilayer electro-optic device as described in any of Clauses 1 to 11, wherein the first adhesive layer comprises a crosslinked acrylic polymer or a mixture of polyurethane and a crosslinked acrylic polymer, the crosslinked acrylic polymer being formed by crosslinking a self-crosslinked acrylic polymer containing epoxy functional groups.

[0158] Clause 13: A chemically resistant multilayer electro-optic device as described in any of Clauses 1 to 12, wherein the chemically resistant multilayer electro-optic device includes a piezoelectric layer comprising a piezoelectric material, the piezoelectric layer being disposed between the first transparent electrode layer and the electro-optic material layer, or between the second electrode layer and the electro-optic material layer.

[0159] Clause 14: A method for manufacturing a chemically resistant multilayer electro-optic device, the chemically resistant multilayer electro-optic device sequentially comprising: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, a first adhesive layer, and a second substrate layer, the method comprising the following steps: (1) providing an electro-optic sheet, the electro-optic sheet sequentially comprising: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, and a second electrode layer, the second electrode layer comprising a conductive polymer; (2) forming a wet film on the second electrode layer of the electro-optic sheet by applying an aqueous adhesive composition to the second electrode layer, the aqueous adhesive composition comprising (i (ii) 20 to 80% by weight of the aqueous adhesive composition, excluding solvent, of polyvinyl alcohol containing acetyl-acetyl functional groups in its molecular structure; and (iii) 20 to 80% by weight of the aqueous adhesive composition, excluding solvent, of polyurethane, self-crosslinking acrylic polymer, or a mixture of polyurethane and self-crosslinking acrylic polymer; and (iii) an aqueous carrier; (3) forming an intermediate electro-optic laminate by applying heat to cure the wet film, the intermediate electro-optic laminate sequentially comprising: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, and an adhesive film, the adhesive film encapsulating... Containing, by weight of the adhesive film excluding solvent, 20 to 80% by weight of polyurethane, crosslinked acrylic polymer, or mixture of polyurethane or crosslinked acrylic polymer, and by weight of the adhesive film excluding solvent, 20 to 80% by weight of polyvinyl alcohol, the polyvinyl alcohol containing acetyl-acetyl functional groups, wherein the adhesive film of the intermediate electro-optic laminate is non-adhesive at room temperature; (4) providing a thermoplastic film having a surface, the thermoplastic film comprising a thermoplastic resin selected from polyethylene, polypropylene, polybutene, polyethylene terephthalate, ethylene copolymer, propylene copolymer, butene copolymer, and mixtures thereof. The group comprising the thermoplastic film having a surface treatment such that the surface of the thermoplastic film contains polar functional groups; (5) at a temperature of 60°C to 100°C, the thermoplastic film is laminated together with the intermediate electro-optic laminate to form a chemically resistant multilayer electro-optic device, the first adhesive layer of the chemically resistant multilayer electro-optic device being disposed between the second substrate layer and the second electrode layer, the second substrate layer comprising a thermoplastic film, wherein at least a portion of the polar functional groups on the surface of the thermoplastic film reacts with the acetyl acetyl functional groups of the polyvinyl alcohol of the adhesive film, such that the surface of the thermoplastic film of the second substrate layer is covalently bonded to the polyvinyl alcohol of the first adhesive layer.

[0160] Clause 15: The method of manufacturing a chemically resistant multilayer electro-optic device as described in Clause 14, wherein the aqueous adhesive composition comprises 0.5 to 8% by weight of a crosslinking agent, excluding solvent, based on the weight of the aqueous adhesive composition, and wherein the adhesive film of the intermediate electro-optic laminate formed in the curing step comprises 20 to 80% by weight of crosslinked polyvinyl alcohol, excluding solvent, based on the weight of the adhesive film, and the crosslinked polyvinyl alcohol of the adhesive film comprises crosslinked acetyl acetyl functional groups and non-crosslinked acetyl acetyl functional groups.

[0161] Clause 16: A method of manufacturing a chemically resistant multilayer electro-optic device as described in Clause 14 or Clause 15, wherein the aqueous adhesive composition comprises a self-crosslinking acrylic polymer or a mixture of polyurethane and a self-crosslinking acrylic polymer, the self-crosslinking acrylic polymer comprising an epoxy functional group.

[0162] Clause 17: A method for manufacturing a chemically resistant multilayer electro-optic device as described in any of Clauses 14 to 16, wherein the electro-optic material layer comprises an electrophoretic medium comprising charged pigment particles, a charge control agent and a nonpolar liquid, and the electrophoretic medium is encapsulated in a plurality of microcells or a plurality of microcapsules.

[0163] Clause 18: The method of manufacturing a chemical-resistant multilayer electro-optic device as described in Clause 17, wherein each of the plurality of microcells comprises a microcell bottom layer, a microcell wall, a microcell opening, and a sealing layer, the sealing layer spanning the microcell opening and contacting a second electrode layer.

[0164] Clause 19: A method for manufacturing a chemically resistant multilayer electro-optic device as described in any of Clauses 14 to 18, wherein the conductive polymer is selected from the group consisting of poly(3,4-ethyldioxythiophene):polystyrene sulfonate (PEDOT-PSS), polyacetylene, polyphenylene sulfide, polystyrene, and combinations thereof.

[0165] Clause 20: A method of manufacturing a chemical-resistant multilayer electro-optic device as described in any of Clauses 14 to 19, wherein the method includes the step of forming a web of the intermediate electro-optic laminate after the intermediate electro-optic laminate is formed.

[0166] 100: Multiple electrodes 101: Base of microcell 102: Microcell wall 103: Microcell opening 200: Electro-optical devices containing microcells 205: Viewing side of the device 210: First transparent electrode layer 211: First substrate layer 212: Second substrate layer 220: Microcellular layer 225: Electrophoretic medium 230: Sealing layer 240: First adhesive layer 242: Water-based adhesive composition 245: Adhesive membrane 248: Second adhesive layer in an electro-optic device containing microcapsules 250: Second electrode layer 260: Electro-optic material layer containing microcells 265: Electro-optic material layer containing microcapsules 290: Electro-optical devices containing microcapsules 300: Electro-optic sheet containing microcells 390: Electro-optic sheet containing microcapsules 400: Intermediate electro-optic laminate containing microcells 400: Intermediate electro-optic laminate containing microcapsules 610: Hot stamping station 620: Web of the electro-optic device 700: Male bond 701: Conductive film 702: Thermoplastic or thermosetting precursor layer 703: Microcell Array 704: Web 800: Microcell Array 801: Radiocure material that forms microcells 802: Conductive film 803: Substrate layer 804: Opaque area of ​​the photomask 805: Transparent area of ​​the photomask 806: Photomask 807: Microcell 814: Lines of the photomask 815: Space between photomask lines 816: Second Light Mask 900: Microcell array containing the first transparent electrode layer 970: Filled microcells containing the first transparent electrode layer 980: Filled and sealed microcells containing the first transparent electrode layer 990: Filled and sealed microcells containing electrodes 1000: Component type containing piezoelectric material layer 1002: Piezoelectric material layer 1100: Component type containing piezoelectric material layer 1200: Component type containing piezoelectric material layer 1300: Component type containing piezoelectric material layer 1312: Semiconductor or high-resistivity layer 1300: Component type containing piezoelectric material layer 1410: Second Semiconductor 1413: Metal layer 1500: Component type containing piezoelectric material layer 1515: Flat portion of the microcell layer

Claims

1. A chemically resistant multilayer electro-optic device, comprising, in sequence: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, a first adhesive layer, and a second substrate layer, wherein the first adhesive layer comprises: 20 to 80% by weight of polyurethane, cross-linked acrylic polymer, or a mixture of polyurethane and cross-linked acrylic polymer, excluding solvent, based on the weight of the first adhesive layer; and 20 to 80% by weight of polyvinyl alcohol, excluding solvent, based on the weight of the first adhesive layer, wherein the polyvinyl alcohol contains acetyl-acetyl functional groups in its molecular structure; the second substrate layer is formed using a thermoplastic film having a surface, the thermoplastic film comprising a thermoplastic resin, the thermoplastic film having a surface treatment such that the surface of the thermoplastic film contains polar functional groups, wherein at least a portion of the polar functional groups are covalently bonded to the polyvinyl alcohol of the first adhesive layer, the covalent bond being formed by the reaction of the acetyl-acetyl functional group of the polyvinyl alcohol with the polar functional group on the surface of the thermoplastic film.

2. The chemical-resistant multilayer electro-optic device of claim 1, wherein the electro-optic material layer comprises an electrophoretic medium comprising charged pigment particles, a charge control agent and a nonpolar liquid, the electrophoretic medium being encapsulated in multiple microcells or multiple microcapsules.

3. The chemical-resistant multilayer electro-optic device of claim 2, wherein each of the plurality of microcells comprises a microcell base layer, a microcell wall, a microcell opening and a sealing layer, the sealing layer spanning the microcell opening and contacting the second electrode layer.

4. The chemical-resistant multilayer electro-optic device of claim 1, wherein the second electrode layer comprises a conductive polymer.

5. The chemically resistant multilayer electro-optic device of claim 4, wherein the conductive polymer is selected from the group consisting of poly(3,4-ethyldioxythiophene): polystyrene sulfonate (PEDOT-PSS), polyacetylene, polyphenylene sulfide, polystyrene, and combinations thereof.

6. The chemically resistant multilayer electro-optic device of claim 1, wherein the thermoplastic film for forming the second substrate layer comprises a thermoplastic resin selected from the group consisting of polyethylene, polypropylene, polybutene, polyethylene terephthalate, ethylene copolymers, propylene copolymers, butene copolymers, and mixtures thereof.

7. The chemically resistant multilayer electro-optic device of claim 1, wherein the first adhesive layer comprises polyurethane or a mixture of polyurethane and crosslinked acrylic polymer, and wherein the glass transition temperature of the polyurethane is below -30°C.

8. The chemical-resistant multilayer electro-optic device of claim 1, wherein the first adhesive layer comprises polyurethane or a mixture of polyurethane and crosslinked acrylic polymer, and wherein the polyurethane is crosslinked.

9. The chemically resistant multilayer electro-optical device of claim 1, wherein the polyvinyl alcohol is cross-linked, and the cross-linked polyvinyl alcohol is formed by reacting the polyvinyl alcohol with a cross-linking agent.

10. The chemically resistant multilayer electro-optic device of claim 9, wherein the crosslinking agent is selected from the group consisting of dialdehyde, diamine and organozirconate.

11. The chemically resistant multilayer electro-optical device of claim 1, wherein the degree of hydrolysis of the polyvinyl alcohol is 90% to 99%.

12. The chemically resistant multilayer electro-optic device of claim 1, wherein the first adhesive layer comprises a crosslinked acrylic polymer or a mixture of polyurethane and a crosslinked acrylic polymer, the crosslinked acrylic polymer being formed by crosslinking a self-crosslinked acrylic polymer containing epoxy functional groups.

13. A chemical-resistant multilayer electro-optic device as claimed in any one of claims 1 to 12, wherein the chemical-resistant multilayer electro-optic device includes a piezoelectric layer comprising a piezoelectric material, the piezoelectric layer being disposed between the first transparent electrode layer and the electro-optic material layer, or between the second electrode layer and the electro-optic material layer.

14. A method for manufacturing a chemical-resistant multilayer electro-optic device, the chemical-resistant multilayer electro-optic device sequentially comprising: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, a first adhesive layer, and a second substrate layer, the method for manufacturing the multilayer electro-optic device comprising the following steps: providing an electro-optic sheet, the electro-optic sheet sequentially comprising: the first substrate layer, the first transparent electrode layer, the electro-optic material layer, and the second electrode layer, the second electrode layer comprising a conductive polymer; By applying an aqueous adhesive composition to the second electrode layer of the electro-optic sheet to form a wet film on the second electrode layer, the aqueous adhesive composition comprises (i) 20 to 80% by weight of the aqueous adhesive composition excluding solvent, wherein the polyvinyl alcohol contains acetyl-acetyl functional groups in its molecular structure; (ii) 20 to 80% by weight of the aqueous adhesive composition excluding solvent, wherein the polyvinyl alcohol contains acetyl-acetyl functional groups in its molecular structure; and (iii) an aqueous carrier. An intermediate electro-optic laminate is formed by applying heat to cure the wet film. The intermediate electro-optic laminate sequentially comprises: a first substrate layer, a first transparent electrode layer, an electro-optic material layer, a second electrode layer, and an adhesive film. The adhesive film comprises 20 to 80% by weight of the polyurethane, the cross-linked acrylic polymer, or a mixture of the polyurethane or the cross-linked acrylic polymer, excluding solvent, based on the weight of the adhesive film, and 20 to 80% by weight of polyvinyl alcohol, excluding solvent, based on the weight of the adhesive film. The polyvinyl alcohol contains acetyl-acetyl functional groups. The adhesive film of the intermediate electro-optic laminate is non-adhesive at room temperature. A thermoplastic film having a surface is provided, the thermoplastic film comprising a thermoplastic resin selected from the group consisting of polyethylene, polypropylene, polybutene, polyethylene terephthalate, ethylene copolymers, propylene copolymers, butene copolymers, and mixtures thereof, the thermoplastic film having a surface treatment such that the surface of the thermoplastic film comprises polar functional groups; the thermoplastic film is pressed together with an intermediate electro-optic laminate at a temperature of 60°C to 100°C to form a chemically resistant multilayer electro-optic device, the first adhesive layer of the chemically resistant multilayer electro-optic device being disposed between a second substrate layer and a second electrode layer, the second substrate layer comprising the thermoplastic film, wherein at least a portion of the polar functional groups on the surface of the thermoplastic film reacts with the acetyl acetyl functional groups of the polyvinyl alcohol of the adhesive film, such that the surface of the thermoplastic film of the second substrate layer is covalently bonded to the polyvinyl alcohol of the first adhesive layer.

15. A method for manufacturing a chemically resistant multilayer electro-optic device as claimed in claim 14, wherein the aqueous adhesive composition comprises 0.5 to 8% by weight of a crosslinking agent, excluding solvent, based on the weight of the aqueous adhesive composition, and wherein the adhesive film of the intermediate electro-optic laminate formed in the curing step comprises 20 to 80% by weight of crosslinked polyvinyl alcohol, excluding solvent, based on the weight of the adhesive film, wherein the crosslinked polyvinyl alcohol of the adhesive film comprises crosslinked acetyl acetyl functional groups and non-crosslinked acetyl acetyl functional groups.

16. A method for manufacturing a chemically resistant multilayer electro-optic device as claimed in claim 14, wherein the aqueous adhesive composition comprises a self-crosslinking acrylic polymer or a mixture of polyurethane and a self-crosslinking acrylic polymer, the self-crosslinking acrylic polymer comprising an epoxy functional group.

17. A method for manufacturing a chemical-resistant multilayer electro-optic device according to any one of claims 14 to 16, wherein the electro-optic material layer comprises an electrophoretic medium comprising charged pigment particles, a charge control agent and a nonpolar liquid, and the electrophoretic medium is encapsulated in a plurality of microcells or a plurality of microcapsules.

18. A method for manufacturing a chemical-resistant multilayer electro-optic device as claimed in claim 17, wherein each of the plurality of microcells comprises a microcell bottom layer, a microcell wall, a microcell opening, and a sealing layer, the sealing layer spanning the microcell opening and contacting the second electrode layer.

19. A method for manufacturing a chemically resistant multilayer electro-optic device as claimed in any one of claims 14 to 16, wherein the conductive polymer is selected from the group consisting of poly(3,4-ethyldioxythiophene): polystyrene sulfonate (PEDOT-PSS), polyacetylene, polyphenylene sulfide, polystyrene, and combinations thereof.

20. A method of manufacturing a chemical-resistant multilayer electro-optic device as claimed in any one of claims 14 to 16, wherein the method includes the step of forming a web of the intermediate electro-optic laminate after the intermediate electro-optic laminate is formed.

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