Reaction setting, polymer, sealing material for liquid crystal displays

• US 4,470,668 A
• Filed: 07/13/1983
• Issued: 09/11/1984
• Est. Priority Date: 04/28/1981
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Inoue, Hiroshi, Kamoi, Sumio
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Lewis, David
• Application Number:
  US06/513,127
• Time in Patent Office: 426 Days
• Field of Search: 350/343, 350/344, 350/339 R, 350/334
• US Class Current: 349/153
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells

Abstract

A sealing material particularly suitable for producing liquid crystal display panels of which the base plates are made of flexible polymer film, which sealing material comprises a reaction-setting type polymer containing siloxane bonds in the molecules, which polymer is represented by the following general formula ##STR1## wherein R represents a lower alkyl group, and X¹, X², X³, X⁴, X⁵, X⁶ and X⁷ independently represent radicals selected from the group consisting of hydroxy, acetoxy, alkoxy, hydrogen, vinyl, epoxy, amino, glycol, phenyl, fluorinated alkyl and lower alkyl, and at least one of X¹ through X⁷ is a radical selected from the group consisting of hydroxy, acetoxy, alkoxy, hydrogen, vinyl, epoxy, amino and glycol, and n represents an integer of 5 to 10000. Since sealing material has high sealing strength for the polymer film over a long period of time and is free from solvents, the liquid crystal, the orientation processed films, the transparent electrodes and the base plates of the liquid display panels are not caused to deteriorate by this sealing material.

Claims

1. In a liquid crystal display element comprising upper and lower substrates both made of flexible polymeric film, a layer of liquid crystal material disposed between said substrates and sealing material surrounding said layer of liquid crystal material and sealing the space between said substrates to form a closed cell, the improvement which comprises:

said sealing material is free of solvents and comprises a reaction-setting type polymer containing siloxane bonds, and shows a characteristic infra-red absorption at least in the range of 1,000 cm^-1 to 1,100 cm^-1.

2. A liquid crystal display element as claimed in claim 1, wherein said reaction-setting type polymer is a polymer represented by the formula ##STR13## wherein R represents a lower alkyl group, and X¹, X², X³, X⁴, X⁵, X⁶ and X⁷ independently represent radicals selected from the group consisting of hydroxy, acetoxy, alkoxy, hydrogen, vinyl, epoxy, amino, glycol, phenyl, fluorinated alkyl and lower alkyl, and at least one of X¹ through X⁷ is a radical selected from the group consisting of hydroxy, acetoxy, alkoxy, hydrogen, vinyl, epoxy, amino and glycol, and n represents an integer of 5 to 10,000.

3. A liquid crystal display element as claimed in claim 1, further comprising a polydimethyl siloxane containing a group of ##STR14## at its molecular end.

4. A liquid crystal display element as claimed in claim 1, further comprising a filler comprising a metal oxide selected from the group consisting of silica gel and titanium oxide.

5. A liquid crystal display element as claimed in claim 1, further comprising a hardening reaction acceleration agent comprising platinate.

6. A liquid crystal display element as claimed in claim 1, wherein said polymer film is a film selected from the group consisting of polyethylene-terephthalate film, polybutylene-terephthalate film, polyether-sulfone film, polycarbonate film and polysulfone film.

7. A liquid crystal display element as claimed in claim 2, wherein, in said general formula, R and X⁷ each represent a methyl group, and at least one of X¹ through X⁶ is hydrogen.

8. A liquid crystal display element as claimed in claim 2, wherein, in said general formula, R represents a methyl group and X⁷ represents a phenyl group.

9. A liquid crystal display element comprising:

a twisted-nematic liquid crystal layer;

upper and lower transparent substrates disposed on opposite sides of said liquid crystal layer, said substrates both being made of flexible polymeric film, selected from the group consisting of polyethylene terephthalate films, polybutylene terephthalate films, polyether sulfone films, polycarbonate films and polysulfone films;

upper and lower transparent electrodes supported on the opposed inner faces of said upper and lower substrates respectively, said electrodes being effective to apply an electric field to said liquid crystal layer;

upper and lower polarizers mounted on the outer faces of said upper and lower substrates; and

a layer of sealing material disposed between said substrates surrounding said liquid crystal layer, said sealing material consisting essentially of a solvent-free, reaction-setting polysiloxane.

10. A liquid crystal display element as claimed in claim 9 including spacer particles disposed between said substrates for maintaining a substantially uniform spacing between said substrates.

11. A liquid crystal display element as claimed in claim 9 including upper and lower liquid crystal orientation films disposed between said upper and lower electrodes and the upper and lower surfaces of said liquid crystal layer, respectively.