Electro-optic display and lamination adhesive

An electro-optic display comprising first and second substrates, and a lamination adhesive layer and a layer of solid electro-optic material disposed between the first and second substrates, the lamination adhesive being characterized by any one or more of the following:

• (a) having a volume resistivity, measured at 10° C., which does not change by a factor of more than about 3 after being held at 25° C. and 45 percent relative humidity for 1000 hours;
• (b) having a peel strength from an electrode material in contact with the lamination adhesive of at least about 2 lb/inch;
• (c) the volume resistivity of the lamination adhesive changes by a factor of less than about 10 within a range of 10 to 90 percent relative humidity and over a temperature range of 10 to 50° C.;
• (d) the lamination adhesive has a thickness in the range of about 10 to about 20 μm;
• (e) the lamination adhesive has a shear modulus at 120° C. of not more than about 1 megapascal;
• (f) the product of the dielectric constant and the volume resistivity of the lamination adhesive is not greater than the product of the dielectric constant and the volume resistivity of the electro-optic medium within a range of 10 to 90 percent relative humidity and over a temperature range of 10 to 50° C.;
• (g) comprising an ultra-violet stabilizer;
• (h) comprising a light absorbing material.

A process for preparing an electro-optic display by providing a first subassembly comprising a solid electro-optic layer and a first substrate, providing a second subassembly comprising a second substrate, at least one of said subassemblies comprising an electrode, and laminating the two subassemblies to one another with a lamination adhesive so that the electro-optic layer is disposed between the first and second substrates, the lamination adhesive being characterized by any one or more of the following:

• (a) having a volume resistivity, measured at 10° C., which does not change by a factor of more than about 3 after being held at 25° C. and 45 percent relative humidity for 1000 hours;
• (b) having a peel strength from an electrode material in contact with the lamination adhesive of at least about 2 lb/inch;
• (c) the volume resistivity of the lamination adhesive changes by a factor of less than about 10 within a range of 10 to 90 percent relative humidity and over a temperature range of 10 to 50° C.;
• (d) the lamination adhesive has a thickness in the range of about 10 to about 20 μm;
• (e) the lamination adhesive has a shear modulus at 120° C. of not more than about 1 megaPascal;
• (f) the product of the dielectric constant and the volume resistivity of the lamination adhesive is not greater than the product of the dielectric constant and the volume resistivity of the electro-optic medium within a range of 10 to 90 percent relative humidity and over a temperature range of 10 to 50° C.;
• (g) comprising an ultra-violet stabilizer;
• (h) comprising a light absorbing material.

An electrophoretic display comprising first and second substrates, and a lamination adhesive layer and a layer of electrophoretic material disposed between the first and second substrates, the electrophoretic material comprising a plurality of capsules, each capsule comprising a capsule wall and an internal phase encapsulated within the capsule wall, the internal phase comprising electrically charged particles suspended in a suspending fluid and capable of moving through the fluid on application of an electric field to the electrophoretic material, the lamination adhesive being characterized by any one or more of the following:

• (a) the product of the dielectric constant and the volume resistivity of the lamination adhesive is from about 0.01 to about 100 times the product of the dielectric constant and the volume resistivity of the suspending fluid;
• (b) the ratio of the dielectric constant of the lamination adhesive to the dielectric constant of the suspending fluid within the temperature range of from 10 to 50° C. does not vary from this ratio at 25° C. by more than about 2 percent;
• (c) the ratio of the volume resistivity of the lamination adhesive to the volume resistivity of the suspending fluid within the temperature range of from 10 to 50° C. does not vary from this ratio at 25° C. by more than a factor of about 100;
• (d) the solubility of the suspending fluid in the lamination adhesive does not exceed about 1 percent weight/weight over the range of 10 to 50° C.;
• (e) being substantially free from mobile species.

A process for preparing an electrophoretic display by providing a first subassembly comprising a first substrate and a layer of an electrophoretic medium comprising a plurality of capsules, each capsule comprising a capsule wall and an internal phase encapsulated within the capsule wall, the internal phase comprising electrically charged particles suspended in a suspending fluid and capable of moving through the fluid on application of an electric field to the electrophoretic medium, providing a second subassembly comprising a second substrate, at least one of said subassemblies comprising an electrode, and laminating the two subassemblies to one another with a lamination adhesive so that the electro-optic layer is disposed between the first and second substrates, the lamination adhesive being characterized by any one or more of the following:

• (a) the product of the dielectric constant and the volume resistivity of the lamination adhesive is from about 0.01 to about 100 times the product of the dielectric constant and the volume resistivity of the suspending fluid;
• (b) the ratio of the dielectric constant of the lamination adhesive to the dielectric constant of the suspending fluid within the temperature over the range of from 10 to 50° C. does not vary from this ratio at 25° C. by more than about 2 percent;
• (c) the ratio of the volume resistivity of the lamination adhesive to the volume resistivity of the suspending fluid within the temperature over the range of from 10 to 50° C. does not vary from this ratio at 25° C. by more than a factor of about 100;
• (d) the solubility of the suspending fluid in the lamination adhesive does not exceed about 1 percent weight/weight over the range of 10 to 50° C.;
• (e) being substantially free from mobile species.

A microcell electrophoretic display comprising a substrate having a plurality of closed cavities formed therein, said cavities being at least partially filled with a electrophoretic medium comprising a plurality of electrically charged particles suspended in a suspending fluid and capable of moving therethrough on application of an electric field to the electrophoretic medium, the microcell electrophoretic display further comprising at least one electrode and a layer of lamination adhesive disposed between the cavities and the electrode, the lamination adhesive being characterized by any one or more of the following:

• (a) having a volume resistivity, measured at 10° C., which does not change by a factor of more than about 3 after being held at 25° C. and 45 percent relative humidity for 1000 hours;
• (b) having a peel strength from an electrode material in contact with the lamination adhesive of at least about 2 lb/inch;
• (c) the volume resistivity of the lamination adhesive changes by a factor of less than about 10 within a range of 10 to 90 percent relative humidity and over a temperature range of 10 to 50° C.;
• (d) the lamination adhesive has a thickness in the range of about 10 to about 20 μm;
• (e) the lamination adhesive has a shear modulus at 120° C. of not more than about 1 megaPascal;
• (f) the product of the dielectric constant and the volume resistivity of the lamination adhesive is not greater than the product of the dielectric constant and the volume resistivity of the electro-optic medium within a range of 10 to 90 percent relative humidity and over a temperature range of 10 to 50° C.;
• (g) comprising an ultra-violet stabilizer;
• (h) comprising a light absorbing material;
• (i) the product of the dielectric constant and the volume resistivity of the lamination adhesive is from about 0.01 to about 100 times the product of the dielectric constant and the volume resistivity of the suspending fluid;
• (j) the ratio of the dielectric constant of the lamination adhesive to the dielectric constant of the suspending fluid within the temperature over the range of from 10 to 50° C. does not vary from this ratio at 25° C. by more than about 2 percent;
• (k) the ratio of the volume resistivity of the lamination adhesive to the volume resistivity of the suspending fluid within the temperature over the range of from 10 to 50° C. does not vary from this ratio at 25° C. by more than a factor of about 100;
• (l) the solubility of the suspending fluid in the lamination adhesive does not exceed about 1 percent weight/weight over the range of 10 to 50° C.;
• (m) being substantially free from mobile species.