CA1127953A - Laminated light-polarizing sheet - Google Patents
Laminated light-polarizing sheetInfo
- Publication number
- CA1127953A CA1127953A CA324,879A CA324879A CA1127953A CA 1127953 A CA1127953 A CA 1127953A CA 324879 A CA324879 A CA 324879A CA 1127953 A CA1127953 A CA 1127953A
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- Prior art keywords
- light
- sheet
- polarizing
- laminated
- carbon atoms
- Prior art date
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Abstract
LAMINATED LIGHT-POLARIZING SHEET The specification discloses a laminated lightpolarizing sheet having an excellent humidity resistance with dimensional stability under conditions of high humidity as well as an excellent light resistance. The sheet has a light-polarizing film of a halogenated vinyl or vinylidene polymer containing polyene chains formed by partial dehydrohalogenation, and a film or sheet of an acrylate or methacrylate polymer laminated on at least one surface of the light-polarizing film.
Description
112"~9s3 The present invention relates to a laminated light-polarizing sheet.
Various films having polarization efficiency, that is, light-polarizing films, are already known, such as films made of polyvinyl alcohol-iodine, polyvinyl alcohol-polyene, polyvinyl alcohol-dichromic dye and the like.
However, since the polyvinyl alcohol used as the base material in these films is a hydrophilic polymer, the light-polarizing films lack humidity resistance.
We have previously developed a polyvinyl halide-polyene light-polarizing film which has improved humidity resistance (e.g. as disclosed in United States Patent No.
3,621,085). This light polarizing film has excellent humidity resistance since the base material thereof is a hydrophobic polymer.
However, since the known light-polarizing films, including the above-mentioned polyvinyl halide-polyene film, are formed into thin films by stretching a thicker film to a great extent in one direction, they are liable to be damaged by crazing, wrinkling or surface defects during handling, crazing during cutting in a direction at right angles to the stretching direction, and the like.
In order to overcome these drawbacks, a cellulose film, such as cellulose triacetate film, has been lam-inated on the light-polarizing film in order to reinforce it. However, the laminated light-polarizing sheet thus obtained still has some drawbacks. For example, in the case of a hydrophilic light-polarizing film, the resulting laminated light-polarizing sheet is hydrophilic and, when it is bonded to a glass plate under conditions of high humidity, bubbles are produced at the bonding interface.
liZ79~;3 Further, when the laminated sheet is maintained under high humidity, it swells due to water absorption and the edge portions thereof tend to peel off. In the case of a hydrophobic light-polarizing film, the light polarizing film itself has a water absorbing capacity of 0.07 to 0.4 ~ whereas the cellulose film, e.g. cellulose triace-tate film, is a hydrophilic film having a water absorbing capacity of 1.8 to 7.0 %. When these two films are laminated together, the hydrophobic light-polarizing film layer of the resulting laminate crazes and wrinkles under conditions of high humidity, such as 80 to 90 % RH, since it does not swell to the same extent as the cellulose film laminated thereon.
In view of these drawbacks, we have made intensive studies to obtain an improved laminated light-polarizing sheet and have found that a sheet having desirable proper-ties can be obtained by laminating a film or sheet of an acrylate or methacrylate polymer (hereinafter referred to merely as a polyacrylate sheet) onto a light-polarizing film of halogenated vinyl or vinylidene polymer containing polyene chains formed by partial dehydrohalogenation.
The main object of the present invention is to pro-vide a laminated light-polarizing sheet having very good humidity resistance with dimensional stability under conditions of high humidity, as well as very good light resistance. Another object of the present invention is to provide a laminated light-polarizing sheet which resists crazing and wrinkling.
According to the invention there is provided a laminated light-polarizing sheet comprising a light-polarizing film of a halogenated vinyl or vinylidene polymer containing polyene chains formed by partial dehydrohalogenation and a film or sheet of an acrylate or methacrylate polymer laminated on at least one surface of the light-polarizing film.
The laminated light-polarizing sheet of the present invention has good dimensional stability since the water absorbing capacity of both the pQlyacrylate sheet and the light-polarizing film is low and the laminated sheet hardly swells even in conditions of high humidity. More-over, the light-polarizing film layer of the laminated sheet hardly crazes and breaks by swelling due to water absorption since the water absorbing capacity of the poly-acrylate sheet layer (0.09 to 0.4 %) is similar to that of the light-polarizing film layer and there is thus little difference in water absorbing capacity between these layers. Further, the polyacrylate sheet layer has optical uniformity and good transparency and the laminated light-polarizing sheet is hardly damaged since the polyacrylate sheet layer is tough and flexible.
The light-polarizing film used in the present invention can be produced from an halogenated vinyl or vinylidene polymer according to the process disclosed in the above United States Patent No. 3,621,085. For example, the light-polarizing film can be produced by partially dehydrohalogenating a film of halogenated vinyl or vinylidene polymer in the presence of a basic compound, heating the film until it becomes blue to violet in order to form polyene chains therein, and then stretching the film in one direction to unidirectionally orient the polyene chains. Alternatively, the light-polarizing film can be produced by partially dehydrohalogenating 1~27953 halogenated vinyl or vinylidene polymer in the form of a solution in the presence of a basic compound, casting the resulting solution into a film, heating the film until the desired light absorption is observed within the visible light wavelength range, whereby polyene chains are formed, and then stretching the film in one direction to unidirec-tionally orient the polyene chains.
The halogenated vinyl or vinylidene polymer used in the production of the light-polarizing film is a homo-polymer or a copolymer of a monomer of the formula:
~Rl CH2 = C \ (I) X
in which X is halogen (preferably, chlorine or bromine);
Rl is hydrogen, -CN, -COOR2, -OOCR3 or an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.);
R2 is an alkyl group having 1 to 10 carbon atoms; and R3 is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.) or a cycloalkyl group having 5 to 10 carbon atoms (e.g. cyclohexyl, etc.). Typical examples of these polymers are a homopolymer or a copolymer of a vinyl halide and/or a vinylidene halide such as vinyl chloride, vinyl bromide, vinylidene chloride and the like. Further, the halogenated vinyl or vinylidene polymer may be a copolymer of the above monomer (I) and up to 90 mol % (based on all structural units of the polymer) of another copolymerizable monomer, preferably a monomer of the formula:
CH2 = C \ (II) 1~Z7953 in which R4 is hydrogen or an alkyl group having 1 to 10 carbon atoms; R5 is hydrogen, a hydrocarbon group having 1 to 10 carbon atoms, such as an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.) or a cycloalkyl group having 5 to 10 carbon atoms (e.g. cyclohexyl, etc.), a hetero-cyclic group having one or more hetero atoms selected from O, N and S (e.g. furfuryl, thienyl etc.) -CN, -COOR6, -OOCR7, or -OH; R6 is hydrogen or an alkyl group having 1 to 10 carbon atoms; R7 is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.), or a cycloalkyl group having 5 to 10 carbon atoms ~e.g. cyclohexyl etc.) and the alkyl chain of the groups R6 and R7 may be interrupted with O, N or S and the hydrocarbon group of R5 may be substituted with one or more halogens. When using a co-polymer of a vinyl halide and a vinylidene halide and/or one or more other copolymerizable monomers, the copolymer must be in the form of a block copolymer or a graft co-polymer so that polyene chains having a sufficient chain length can be formed, and it is preferable that the average chain length (polymerization degree) of a poly-vinyl halide block or a polyvinylidene halide block in the copolymer be more than 20. When the chain length is less than 20, it is difficult to obtain light-polarizing elements (polyene chains) having sufficient activity within the visible light range. Further, it is preferable that the molar ratio of the vinyl halide or the vinylidene halide to all the structural units of the polymer be 0.1/1 to 1/1, more preferably 0.5/1 to 1/1.
Suitable examples of block copolymers are as follows ~279S3 (they are shown by their monomer structural units wherein "VC" and "VB" stand for vinyl chloride and vinyl bromide, respectively):
VC-vinyl acetate, VC-acrylonitrile, VC-ethylene, VC-propylene, VC-styrene, VC-butadiene, VC-isoprene, VC-vinylidene chloride, VC-acrylic acid, VC-methyl acrylate, VC-methyl methacrylater VC-ethylene trifluoride, VB-vinyl acetate, VB-acrylonitrile, VB-ethylene, VB-pro-pylene, VB-vinylidene chloride, VB-styrene, VB-acrylic acid, VB-methyl acrylate, VB-methyl methacrylate, VC-vinyl acetate-vinyl alcohol, VC-vinylidene chloride-methyl acrylate, VC-vinyl fluoride-ethylene tetrafluoride, VB-styrene-methyl acrylate, ~-chlorovinylbenzene-vinyl-benzene, ~-chloroacrylonitrile-acrylonitrile and -chloro-acrylonitrile-methacrylic acid. Suitable examples of graft copolymers are polyvinyl chloride graft-copolymerized with methyl methacrylate or styrene, polyvinyl bromide graft-copolymerized with styrene and the like.
These polymers or copolymers capable of forming polyene chains can be used alone or in any combination with each other.
If necessary, one or more other polymers and additives, such as a stabilizer, a UV absorbing agent, a dye, an antistatic agent and the like, can be added to the light-polarizing f ilm.
The thickness of the light-polarizing film used in the present invention is not critical ~ut is usually in the range o 1 to 200~, preferably 5 to 50~.
The polyacrylate sheet used in the present invention is a non-oriented sheet produced from an acrylate or methacrylate polymer by a conventional method, such as llZ7953 emulsion casting, solution casting, melt extrusion and the like.
The acrylate or methacrylate polymer used in the present invention is preferably a homopolymer or a co-polymer of a monomer of the formula:
lR8 CH2 = C - COORg (III) in which R8 is hydrogen or an alkyl group having 1 to 10 carbon atoms (preferably hydrogen or methyl); and Rg is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms (e.g.
cyclohexyl, isomenthyl, isobornyl, etc.), an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.), an aralkyl group having 7 to 10 carbon atoms (e.g. benzyl, p-isopropylbenzyl or a heterocyclic group containing one or more hetero atoms selected from O, N and S (e.g. fur-furyl, thienyl etc.), and the alkyl chain of the group Rg may be interrupted with O, N or S and the alkyl or aryl group may be substituted with one or more halogens ~e.g. bromine, etc.). Further, the acrylate or meth-acrylate polymer used in the invention may be a copolymerof the above monomer (III) and up to 5~ mol ~ (based on all the structural units of the polymer) of another copoly-merizable monomer of the formula:
~Rl o CH2 = C \ (IV) Rll in which Rlo is hydrogen or an alkyl group having 1 to 10 carbon atoms (preferably, hydrogen or methyl); and Rll is a hydrocarbon group having 1 to 10 carbon atoms, such as an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.), or a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms (e.g. cyclohexyl, etc.), a heterocyclic group having one or more hetero atoms selected from O, N and S (e.g. furfuryl, thienyl etc.~, -CN, -OH or -OOCR12; R12 is an alkyl group having 1 to 10 carbon atoms and the alkyl chain of the groups Rll and R12 may be interrupted with o, N, S, or -COO- and the group Rll may be substituted with one or more OH or halogens (e.g. bromine, etc.). Examples of the acrylate or methacrylate polymer are homopolymers such as poly-methyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polymethyl acrylate, polyethyl acrylate and the like; bipolymers such as methyl methacrylate-ethyl methacrylate copolymer, methyl methacrylate-propyl methacrylate copolymer, methyl methacrylate-butyl methacrylate copolymer, ethyl methacrylate-propyl methacrylate copolymer, methyl methacrylate-methyl acrylate copolymer, ethyl methacrylate-methyl acrylate copolymer, methyl methacrylate-ethyl acrylate copolymer, methyl acrylate-methyltriglycol acrylate copolymer, methyl methacrylate-methyltriglycol acrylate copolymer, methyl methacrylate-stearyl acrylate copolymer, methyl methacry-late-stearyl methacrylate copolymer, ethyl methacrylate-ethylacrylate copolymer, methyl methacrylate-butyl acrylate copolymer, methyl methacrylate-propyl acrylate copolymer, methyl methacrylate-2-hydroxyethyl methacrylate copolymer, methyl methacrylate-2-hydroxypropyl methacrylate copol~mer, ethyl methacrylate-2-hydroxyethyl methacrylate copolymer, ethyl methacrylate-2-hydroxypropyl methacrylate copolymer,methyl methacrylate-2-hydroxyethyl acrylate copolymer, methyl methacrylate-2-hydroxypropyl acrylate copolymer, ethyl methacrylate-2-hydroxyethyl acrylate copolymer, ethyl meth-acrylate-2-hydroxypropyl acrylate copolymer, methyl meth-acrylate-tetrahydrofurfuryl acrylate copolymer, methyl methacrylate-tetrahydrofurfuryl methacrylate copolymer, ethyl methacrylate-tetrahydrofurfuryl acrylate copolymer, ethyl methacrylate tetrahydrofurfuryl methacrylate copolymer, methyl methacrylate-benzyl acrylate copolymer, methyl methacrylate-benzyl methacrylate copolymer, methyl meth-acrylate-benzyl acrylate copolymer, methyl methacrylate-phenoxyethyl acrylate copolymer, methyl methacrylate-phenoxy-ethyl methacrylate copolymer, methyl methacrylate-cyclohexyl acrylate copolymer, methyl methacrylate-cyclohexyl meth-acrylate copolymer, methyl methacrylate-glycidyl acrylate copolymer, methyl methacrylate-glycidyl methacrylate copolymer, ethyl methacrylate-tribromophenyl acrylate copolymer,methyl methacrylate-dibromopropyl acrylate copolymer, methyl methacrylate-tropine acrylate copolymer, methyl methacry-late-tropine methacrylate copolymer, methyl acrylate-tropine methacrylate copolymer, ethyl methacrylate-tropine acrylate copolymer, methyl methacrylate-isobornyl methacrylate co-polymer, methyl methacrylate-isobornyl acrylate copolymer, ethyl methacrylate-isobornyl methacrylate copolymer, propyl methacrylate-isobornyl methacrylate copolymer, methyl methacrylate-isomenthyl acrylate copolymer, metyl meth-acrylate-isomenthyl methacrylate copol~mer, ethyl ~eth-acrylate-isomenthyl methacrylate copolymer, methyl acxylate-acrylonitrile copolymer, butyl acrylate-acrylonitrile co-polymer, n-propyl acrylate-acrylonitrile copolymer and the like; and terpolymers such as methy methacrylate-ethyl methacrylate-butyl methacrylate co~olymer, methyl meth-acrylate-ethyl methacrylate-methyl ~crylate copolymer, methyl methacrylate-ethyl methacrylate-methyltriglycol acrylate copolymer, methyl methacrylate-ethyl methacrylate-stearyl acrylate copolymer, methyl methacrylate-ethyl meth-acrylate-stearyl methacrylate copolymer, methyl methacry-late-ethyl methacrylate-tetrahydrofurfuryl acrylate copoly-mer, methyl methacrylate-ethyl methacrylate-tetrahydro-furfuryl methacrylate copolymer, methyl methacrylate-ethyl methacrylate-benzyl acrylate copolymer, methyl methacrylate-ethyl methacrylate-benzyl methacrylate copolymer, methyl methacrylate-ethyl methacrylate-phenoxyethyl acrylate co-polymer, methyl methacrylate-ethyl methacrylate-phenoxyethyl methacrylate copolymer, methyl methacrylate-ethyl meth-acrylate-cyclohexyl acrylate copolymer, methyl methacrylate-ethyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-ethyl methacrylate-glycidyl acrylate copolymer, methyl methacrylate-ethyl methacrylate-glycidyl methacrylate copolymer, methy methacrylate-ethyl methacrylate-tribromo-phenyl acrylate copolymer, methyl methacrylate-ethyl meth-acrylate-tribromophenyl methacrylate copolymer, methyl methacrylate-ethyl methacrylate-dibromophenyl methacrylate copolymer, methyl methacrylate-methyl acrylate-benzyl ~eth-` acrylate copolymer, methyl methacrylate-methyl acrylate-cyclohexyl acrylate copolymer, methyl methacrylate-methyl ~F~, acrylate-glycidyl methacrylate copolymer, methyl methacrylate-methyl acrylate-tribromophenyl methacrylate copolymer and the like. The thickness of the polyacrylate sheet can be varied widely but usually it is in the range of 5 to 10,000~ in order to provide good transparency and workability.
The laminated light-polarizing sheet of the present invention is produced by laminating the polyacrylate sheet on either or both surfaces of the light-polarizing film.
The lamination can be carried out by various methods.
For example, the lamination can be carried out by bonding the polyacrylate sheet to the light-polarizing film with an adhesive. Suitable examples of the adhesive to be used are an urethane adhesive (e.g. Adcoat 503-35 -Trade Mark- produced by Toyo Morton Co., Ltd.), an acrylate adhesive (e.g. SK-Daine lOOA, 701, 902 and 1002 -Trade Marks- produced by Soken Kagaku Co., Ltd.; Rheocoat 1020 -Trade Mark- produced by Rheochemical Co., Ltd.~, a nitrile adhesive (e.g. Cemedaine 210 -Trade Mark- produced by Cemedaine Co., Ltd.) and the like.
When the surface of the polyacrylate sheet is adhesively activated by wetting with a solvent, the lamination can be carried out by wetting the surface of the polyacrylate sheet with a solvent and immediately pressing it on the surface of the light-polarizing film to bond the sheet and the film. For example, when the polyacrylate sheet is made of an alkyl acrylate copolymer which is prepared from predominantly methyl methacrylate or ethyl methacrylate, the sheet can be readi~y wetted with a solvent such as an alcohol, a ketone, an ester or an ether and bonded to the light-polarizing film to obta;n ~127953 one form of laminated light-polarizing sheet of the present invention.
The lamination can also be carried out by melt extruding, injection molding or casting-thermosetting the above acrylate or methacrylate polymer on the surface of the light-polarizing film or heat-bonding the polyacrylate sheet to the light-polarizing film. Particularly when a thick laminated light-polarizing sheet is desired, it is preferable to carry out the lamination by melt extruding, injection molding or casting-thermosetting the acrylate or methacrylate polymer on the surface of the light-polarizing film. These methods are easily controllable and a hard and thick sheet can be obtained in a short time. Moreover, the resulting laminated light-polarizing sheet has good optical uniformity and good mechanical properties since little wrinkling and bubbling are produced by these methods.
The laminated light-polarizing sheet of the present invention can be used as it is in various fields, but it may be laminated on either or both surfaces thereof with another sheet material in order to reinforce the sheet, by which damage of the sheet by external force ~e.g. bending) can be prevented and further the heat deterioration can be reduced.
- Examples of such sheet material are the same or a different ~ind of the above polyacrylate sheets, as well as polyester sheets such as polyethylene terephthalate-isophthalate sheet, polybutylene terephthalate sheet, poly(ethylene-diethylene)terephthalate sheet; a poly-carbonate sheet such as poly(4,4'-diphenylpropane)carbonate sheet; ~ polyamide sheet such as nylon 6 sheet, nylon 66 ~Z7~;3 sheet, nylon 6-nylon 66 sheet, polyxylylene azipamide sheet, a polyolefin sheet such as polyethylene sheet, poly-propylene sheet, polybutene-l sheet; a polyvinyl sheet such as polystyrene sheet, polyvinyl chloride-vinylidene chloride sheet; a cellulose sheet such as c~llulose acetate sheet, cellulose triacetate sheet;
glass and the like. The laminating can be carried out by bonding the sheet material to the surface of the laminated light-polarizing sheet with an adhesive or a pressure sensitive adhesive or by casting a solution or a melt of the above sheet material on the surface of the laminated light-polarizing sheet. Alternatively, the sheet material can be heat-bonded to or injected on the surface of the polyacrylate sheet layer of the laminated light-polarizing sheet.
The laminated light-polarizing sheet thus obtained has light resistance since the polyacrylate sheet has UV
screening properties. However, when an improved light resistance is required in order to prevent photo-deterioration of the laminated light-polarizing sheet, it is preferable to impart light filter properties to the light-polarizing film layer or another layer of the laminated light-polarizing sheet, or if any, the adhesive layer, so that at least one of these layers has a light transmittance of not less than 60 % within the wavelength range of 500 to 800m~ and of not more than 10 ~ within the wavelength range of 230 to 420 m~.
The light filter properties can be provided by treating the polyacrylate sheet in a solution of a yellow dye having a maximum light absorption around 400 m~ and a UV absorber at a temperature from room temperature to the ~1;~7953 softening point of the polymer thereof for several seconds to several tens of minutes, washing with water (or removing a solvent) and then drying. Alternatively, the yellow dye and the W absorber may be admixed with the materials of the polyacrylate sheet, the light-polarizing film or the adhesive before forming the sheet, film or adhesive layer.
Suitable examples of the yellow dye having a maximum light absorption around 400 m~ are a disperse dye such as C.I. Disperse Yellow 17 ~ and the like, a direct dye such as Direct Fast Yellow 5G ~, C.I. Direct Yellow 17 ~, C.I.
Direct Yellow 20 ~ and the like. These dyes can be used alone or in any combination thereof. When the poly-acrylate sheet is treated in a solution, the solution preferably has a concentration of the yellow dye of 0.1 to 5 parts by weight per 100 parts by weight of the solvent.
The UV absorber preferably has a light absorption capacity over a wide wavelength range towards the long wavelengths. Suitable examples of the W absorber are a benzophenone derivative such as 2,2'-dihydroxy-4,4'-di-methoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone and the like. These UV absorbers can be used alone or in any combination thereof. When the polyacrylate sheet is treated in a solution, the solution has preferably a con-centration of the UV absorber of 0.1 to 10 parts by weight - per 1~0 parts by weight of the solvent.
When the yellow dye and the UV absorber are admixed with the materials of the polyacrylate sheet, light-polarizing film or adhesive, the amount of the dye and the UV absorber vary with the thickness of the sheet, film or adhesive layer, but, usually it is preferable to use 0.05 to 5 parts by weight of the dye and 0.05 to 10 parts by weight of the UV absorber per 100 parts by weight of the materials.
Examples of the solvent for the dye and the W
absorber are an alcohol such as methanol, ethanol, butanol and the like; an ether such as methyl cellosolve, ethyl cellosolve, methyl carbitol, ethyl carbitol and the like;
a glycol such as ethylene glycol, diethylene glycol and the like; an ester such as ethyl acetate, methyl acetate and the like.
The laminated light-polarizing sheet of the present invention can be suitably used in the liquid crystal display device of watches, electric computers and other various instruments. The laminated light-polarizing sheet can also be used in other various fields such as sunvisors, displays, interior decorations and the like.
Besides, in the production of liquid crystal displays, it is necessary to bond the laminated light-polarizing sheet of the present invention to a liquid crystal cell, a reflex plate and the like. Therefore, it is convenient to provide a pressure sensitive adhesive layer on either or both surfaces of the laminated light-polarizing sheet and/or a reflex plate on either surface of the laminated light-polarizing sheet. These laminated light-polarizing sheets having pressure sensitive adhesive layers and/or a reflex plate are also included in the scope of the present invention.
Examples of the pressure sensitive adhesive are a natural rubber, a synthetic rubber elastomer, vinyl chloride-vinyl acetate copolymer, polyvinyl alkyl ether, polyalkyl acrylate and the like. Usually, the thickness ~1279s3 of the pressure sensitive adhesive layer is about 5 to about 30~. It is preferable that the surface of the pressure sensitive adhesive layer is covered by a release paper or film.
A thin plate of 10 to 100~ in thickness plated with gold, silver, cooper, aluminum, chrome and the like can be used as the reflex plate. A plastic film having a metal deposited thereon can also be used as the reflex plate.
It is useful to deposit a metal on a plastic film having an uneven surface since the resulting deposited film becomes a non-directional reflex plate. Further, the function as the reflex plate can be provided by depositing a metal, such as aluminum, on either surface of the poly-acrylate sheet of the laminated light-polarizing sheet.
In this case, the thickness of the deposit is about 50 to 3,000 A.
Preferred forms of the invention are described below with reference to the accompanying drawings, in which:
Fig. 1 is a graph showing the light transmittance curve of a laminate obtained in Examplé 3; and Fig. 2 is a cross-sectional view of a laminated light-polarizing sheet.
Examples of the construction of the laminated light-polarizing sheet are as follows (wherein 1 is a light-- polarizing film layer, 2 is an adhesive layer, 3 is a polyacrylate sheet layer, 4 is another transparent sheet material layer, 5 is a pressure sensitive adhesive layer, 6 is a reflex plate layer, and 7 is a release film layer~:
(1) The laminated light-polarizing sheet comprising the light-polarizing film layer and the polyacrylate sheet layer:
~lZ7~5;~
1/3, 3/1/3, 1/2/3, 3/2/1/2/3, 3/2/1/2/4, 4/3/2/1/2/3/4 ~ 2) The laminated light-polarizing sheet comprising the light-polarizing film layer, the polyacrylate sheet layer and the pressure sensitive adhesive layer:
7/5/1/3, 7/5/1/2/3, 7/5/1/2/3/5/7, 7/5/3/1/3, 7/5/3/2/1/2/3, 7/5/3/2/1/2/3/5/7 - 16a -,. .-- ,~ . ', ~,..~
~Z7953 (3) The laminated light-polarizing sheet com-prising the light-polarizing film layer, the polyacr~late sheet layer and the reflex plate la~er:
6/2/1/3, 6/5/1/3, 6/5/1/2/3, 6/2/1/2/3, 6/2/1/3/5/7, 6/5/1/2/3/5/7, 6/2/1/2/3/5/7, 6/5/3/2/1/2/3, 6/2/3/2/1/2~3, 6/5/3/2/1/2/3/5/7, 6/2/3/2/1/2/3/5/7.
The following Examples illustrate the present in-~ention but are not to be constxued as limiting the scope thereof.
Example 1 (a) An adhesi~e solution of the following com-position was coated on one surface of a polyethylene tere-phthalate release film (50~) with a doctor knife (gap:
4/1,000 inch~ and dried on a metal frame at 80C for 2 minutes in a hot-air drying chamber. The coating weight was 12.4 g/m2.
Composition of the adhesive solution Acrylic adhesive (SK-Daine 701) 10 parts by weight Curing agent 0.0022 "
Ethyl acetate 90 "
A polyacrylate sheet produced from methyl metha-crylate-ethyl acrylate copolymer was bonded to the surface of the adhesive layer on the film at 50~C for 2 seconds under a pressure of 2.0 kg/cm2. A~ter removing the release film, a polyene-containing light-polarizing film produced by partial dehydrohalogenation of p~lyvinyl chloride (20 ~ was bonded to the adhesive layer on the polyacrylate sheet at 60C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet (construction: 3/2/1).
(b) The surface of the light-polarizing film layer l~Z7953 of the above-obtained laminated light-polarizing sheet (opposite face to the polyacrylate sheet-bonding surface) was bonded to an adhesiYe layer which is formed on another polyacylate sheet produced by the same procedure in the above (a) at 60C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet, both surfaces of which are laminated with a polyacrylate sheet (construction: 3/2/1/2/3).
(c) A pressure sensitive adhesive layer coyered by a release film was provided on one surface of the laminated light-polarizing sheet obtained in the above (b) in the following manner.
A pressure sensitive adhesive solution of the following composition was coated on one surface of a poly-ethylene terephthalate release film (50 ~) with a doctor knife (gap: 4/1,000 inch) and dried on a metal frame at 80C for 2 minutes in a hot-air drying chamber, by which the pressure sensitive composition was coated in an amount of 11.0 g/m .
Composition of the pressure sensitive adhesive solution Acrylate pressure sensitive adhesive 10 parts by weight (SK-Daine lOOB) Ethyl acetate 26 "
To the surface of the pressure sensitive adhesive layer thus formed was further bonded the laminated light-polarizing sheet produced in the same manner as in the .
above (b) at 60~C for 2 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet (construction: 7/5/3/2/1/2/3).
(d) For comparative purpose, according to the 1~i3 same procedures as in the above (a) to (c), to both surfaces of the polyene-containing light-polarizing film (20 ~) were bonded cellulose triacetate films (Fujitac produced by Fuji Film Co., Ltd., 50 ~) with the above adhesive solution and one surface thereof was provided with a pressure sensitive adhesive layer covered by the release film to obtain a laminated light-polarizing sheet.
These laminated light-polarizing sheets were cut into a piece of 1.5 cm x 2.0 cm and carefully bonded to liquid crystal cells. These cells were allowed to stand at 60C for 20 hours under 90 % RH. The cellulose film-laminated light-polarizing sheet of (d) crazed along the stretching direction of the light-polarizing film layer thereof and bubbles were observed between the cell and the pressure sensitive adhesive layer thereof. To the contrary, the polyacrylate sheet-laminated light-polari~ing sheets of (a) to (c) did not craze and no bubble was observed.
Example 2 A pressure sensitive adhesive solution of the following composition was coated on one surface of a poly-ethylene terephthalate release film (50 ~) and dried at 80C for 2 minutes. The pressure sensitive adhesive com-position was coated in an amount of 11.0 g/cm .
Composition of the pressure sensitive adhesive solution - Acrylate pressure sensitive adhesiYe 10 parts by weight (SK-Daine lOOB) Ethyl acetate 26 "
To the surface of the adhesive layer of the film obtained above ~as bonded the light-polarizing film layer of the laminated light-polarizing sheet obtained in Example - l~Z7953 1 (a) at 60C for 2 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet (construction: 3/2/1/5/7).
The laminated light-polarizing sheet thus obtained had an excellent adhesion workabilit~.
Example 3 (a) An adhesive solution (A) having a light filter activity of the following composition was coated on one surface of a polyethylene terephthalate release film (50 ~) and dried at 60C for 2 minutes. The adhesive solution was coated in an amount of 9.7 g/m2.
Composition of the adhesive solution (A) Urethane adhesive (Adcoat 503-35) ~ 50 parts by weight Yellow dye (C.I. Disperse ~ellow 60) ~ 0.125 "
UV absorber (2,2',4,4'-tetrahydroxy- 1.5 "
benzophenone) Ethyl acetate 25 "
Methyl ethyl ketone 25 "
A polyacrylate sheet produced from methyl metha-crylate-ethyl acrylate copolymer was bonded to the surface of the adhesive layer on the film obtained above at 60C
for 2 seconds under a pressure of 2.0 kg/cm2. The thus obtained laminate had a light transmittance of not less than 35 % within the visible light wavelength range of more than 425 m~ and not more than 10 % within the wavelength range of 230 to 390 m~ as shown in the light transmittance curve of the accompanying Figure 1.
After removing the polyethylene terephthalate release film, to the adhesive layer of the resulting poly-acrylate sheet was bonded a polyene-containing light-polarizing film produced by partial dehydrohalogenation . ,~
~27953 of poly~inyl chloride (20 ~ at 85C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet bonded with a polyacrylate sheet la~er having light filter properties on one surface of the light-polarizing film.
(b) In the same manner as described in the above (a), another polyacrylate sheet having an adhesive layer was formed by using an adhesi~e solution (B~ of the following composition.
Composition of the adhesive solution (B) Urethane adhesive (Adcoat 503-35) 50 parts by weight Methyl ethyl ketone 25 "
Ethyl acetate 25 "
The surface of the light-polarizing film layer of the laminated light-polarizing sheet obtained in (a) was bonded to the surface of the adhesive layer of the polyacrylate sheet obtained above at 60C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet having the polyacrylate sheet layer on both surfaces of the light-polarizing film.
(c) In the same manner as described in Example 1 (c), to the surface of the layer of the adhesive solution (B) of the laminated light-polarizing sheet obtained in the above (b) was provided with a layer of a pressure sensitive adhesive in the following manner.
That is, the same pressure sensitive adhesive solution as used in ~xample 1 (c) was coated on one surface of a polyethylene terephthalate release film L50 ~) with a doctor ~nife (gap: 4/1,000 inch) and dried on a metal frame at 80c for 2 minutes in a hot air drying chamber ~7953 (the coated amount of the pressure sensitiye adhesive:
11. 0 kg/cm2) .
To the surface of the pressure sensitiYe adhesiYe layer thus formed was bonded the laminated light-polarizing sheet obtained in the aboYe (b~ at 60C for 2 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet having light filter properties (construc-tion: 7/5/3/2/1/2/3).
The laminated light-polarizing sheet thus obtained was cut into a piece of 2 cm x 7 cm and bonded to a liquid crystal cell. The cell was allowed to stand at 70C
under 95 % RH and no damage such as crazing was observed even if after lO0 hours. Further, the cell was exposed to a xenon fadeometer for lO0 hours but display performance thereof hardly changed as shown in the following table.
Before exposure After exposure Ho 39 % 42 %
Hgo 17 ~ 21 ~
(Ho is the average percent light transmitted with the polari-zation axes parallel. Hgo is the average percent light transmitted with the polarization axes crossed. The light transmittance was measured within the waYelength range of 400 to 700 m~ at intervals of lO m~.) Example 4 The surface of the light-polarizing film layer of the laminated light-polarizing sheet obtained in Example 3 (a) was bonded to an adhesive layer formed on a cellulose triacetate film (Fujitac produced by Fuji Film Co., Ltd.
50~), said adhesive layer ~eing formed by the same procedure as in Example 3 (a) using the adhesive solution (B), at 60C
11~7953 for 3 seconds under ~ pressu~e of 2.0 k~/c~2 to obtain a laminated light-polarizing sheet having the polyacrylate sheet layer and the cellulose triacetate fil~ layer on each surface of the light-polarizing film ~construction:
3/2/1/2/4). The laminated light-polarizing sheet was allowed to stand at 75C for 10 days under 95 % RH but no crazing and no change were observed.
Example 5 According to the same procedure in Example 1 (a), a polyacrylate sheet layer produced from methyl methacrylate- .
ethyl acrylate copolymer was bonded to a polyene-containing light-polarizing film produced by partial dehydrohalogena-tion of polyvinyl chloride to obtain a laminated light-polarizing sheet (construction: 3/2/1). The surface of the light-polarizing film layer of the laminated light-polariz-ing sheet was bonded to an adhesive layer on an aluminum reflex plate (20u , reflectance: 85 ~) (formed by coating the same adhesive solution as used in Example 1 on the aluminum plate) at 60C for 2 seconds under a pressure of 1.5 kg/cm2 to obtain a laminated light-polarizing sheet having a reflex plate layer (construction: 3/2/1/2/6).
Example 6 The release film of the laminated light-polarizing sheet obtained in Example 2 was removed. An aluminum réflex plate (20 ~, reflectance: 35 ~) washed with acetone at severa. times was pressed onto the pressure sensitive adhesive layer of the laminated light-polarizing sheet at room temperature for 2 seconds under a pressure of 2.0 kg/cm2 `to obtain a laminated light-polarizing sheet having a reflex plate layer (construction: 3/2/1/5/6).
~ . __ llZ7953 Example 7 A polyvinyl chloride was partially dehydro-halogenated to obtain a polyene-containing film. The film was stretched in one direction to obtain a light-polarizing film.
A methyl methacylate-methyl acrylate copolymer (molar ratio of copolymerization: 50 : 50~ was molten and extruded through a slit to obtain a non-oriented sheet of 20 ~ in thickness.
The above-obtained light-polarizing film and the polyacrylate sheet thus obtained were bonded with an acrylate adhesive (SK-Daine lOOOA ~ ) as shown in the accompanying ~igure 2 (which is the cross section of the laminate in which 1 is the light-polarizing film, 2 is the adhesive layer (thickness: 5 ~) and 3 is the polyacrylate sheet layer) to obtain a laminated light-polarizing sheet (construction:
3/2/1/2/3).
The laminated light-polarizing sheet was fixed in a metal frame die and the die was closed with a cover plate. A molten acrylate resin (Delpet ~ , produced by Asahi Kasei Co., Ltd.) was injected into the die through a nozzle of an extruder (produced by Nippon Seiko Co., Ltd.; die being cooled with water, cylinder temperature: 180 to 220C, nozzle temperature: 220C, sum of injection time and curing time: 10 seconds, injection pressure: 100 kg/cm2, back pressure: 20 kg/cm2) to obtain a laminated light-polarizing sheet of 2 mm in thickness (construction: 3/2/1/2/3/4).
The laminated light-polarizing sheet thus obt~ined had an excellent polarization efficiency and a bright field 30 of view. ~ach layer of the sheet had an excellent bond ~ - 24 -1:127953 strength. Further, when the sheet was allowed to stand at 80C under 95 % RH, no damage such as crazing was observed.
Example 8 An acrylate adhesive (SK-Daine 701] was coated on one surface of a polyethylene terephthalate release film with a doctor knife and dried at ~0C for 2 minutes. An poly-acrylate sheet produced from methyl methacrylate-butyl metha-crylate copolymer (m.p. 70C) was bonded to the adhesive layer on the film obtained above at 50C for 2 seconds under a pressure of 2.0 kg/cm . After removing the release film, a polyene-containing light-polarizing film produced form polyvinyl chloride (20~ was bonded to the adhesive layer of the above-obtained polyacrylate sheet at 60C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet.
The surface of the light-polarizing film layer of the above-obtained laminated light-polarizing sheet was heat-bonded to a hard transparent polyvinyl chloride sheet (500 ~) at 120C for about 10 minutes under a pressure of 60 kg/cm2 to obtain a laminated light-polarizing sheet having excellent polarization efficiency and light transmit-tance (construction: 3/2/1/4).
.. _ . . . . . .
Various films having polarization efficiency, that is, light-polarizing films, are already known, such as films made of polyvinyl alcohol-iodine, polyvinyl alcohol-polyene, polyvinyl alcohol-dichromic dye and the like.
However, since the polyvinyl alcohol used as the base material in these films is a hydrophilic polymer, the light-polarizing films lack humidity resistance.
We have previously developed a polyvinyl halide-polyene light-polarizing film which has improved humidity resistance (e.g. as disclosed in United States Patent No.
3,621,085). This light polarizing film has excellent humidity resistance since the base material thereof is a hydrophobic polymer.
However, since the known light-polarizing films, including the above-mentioned polyvinyl halide-polyene film, are formed into thin films by stretching a thicker film to a great extent in one direction, they are liable to be damaged by crazing, wrinkling or surface defects during handling, crazing during cutting in a direction at right angles to the stretching direction, and the like.
In order to overcome these drawbacks, a cellulose film, such as cellulose triacetate film, has been lam-inated on the light-polarizing film in order to reinforce it. However, the laminated light-polarizing sheet thus obtained still has some drawbacks. For example, in the case of a hydrophilic light-polarizing film, the resulting laminated light-polarizing sheet is hydrophilic and, when it is bonded to a glass plate under conditions of high humidity, bubbles are produced at the bonding interface.
liZ79~;3 Further, when the laminated sheet is maintained under high humidity, it swells due to water absorption and the edge portions thereof tend to peel off. In the case of a hydrophobic light-polarizing film, the light polarizing film itself has a water absorbing capacity of 0.07 to 0.4 ~ whereas the cellulose film, e.g. cellulose triace-tate film, is a hydrophilic film having a water absorbing capacity of 1.8 to 7.0 %. When these two films are laminated together, the hydrophobic light-polarizing film layer of the resulting laminate crazes and wrinkles under conditions of high humidity, such as 80 to 90 % RH, since it does not swell to the same extent as the cellulose film laminated thereon.
In view of these drawbacks, we have made intensive studies to obtain an improved laminated light-polarizing sheet and have found that a sheet having desirable proper-ties can be obtained by laminating a film or sheet of an acrylate or methacrylate polymer (hereinafter referred to merely as a polyacrylate sheet) onto a light-polarizing film of halogenated vinyl or vinylidene polymer containing polyene chains formed by partial dehydrohalogenation.
The main object of the present invention is to pro-vide a laminated light-polarizing sheet having very good humidity resistance with dimensional stability under conditions of high humidity, as well as very good light resistance. Another object of the present invention is to provide a laminated light-polarizing sheet which resists crazing and wrinkling.
According to the invention there is provided a laminated light-polarizing sheet comprising a light-polarizing film of a halogenated vinyl or vinylidene polymer containing polyene chains formed by partial dehydrohalogenation and a film or sheet of an acrylate or methacrylate polymer laminated on at least one surface of the light-polarizing film.
The laminated light-polarizing sheet of the present invention has good dimensional stability since the water absorbing capacity of both the pQlyacrylate sheet and the light-polarizing film is low and the laminated sheet hardly swells even in conditions of high humidity. More-over, the light-polarizing film layer of the laminated sheet hardly crazes and breaks by swelling due to water absorption since the water absorbing capacity of the poly-acrylate sheet layer (0.09 to 0.4 %) is similar to that of the light-polarizing film layer and there is thus little difference in water absorbing capacity between these layers. Further, the polyacrylate sheet layer has optical uniformity and good transparency and the laminated light-polarizing sheet is hardly damaged since the polyacrylate sheet layer is tough and flexible.
The light-polarizing film used in the present invention can be produced from an halogenated vinyl or vinylidene polymer according to the process disclosed in the above United States Patent No. 3,621,085. For example, the light-polarizing film can be produced by partially dehydrohalogenating a film of halogenated vinyl or vinylidene polymer in the presence of a basic compound, heating the film until it becomes blue to violet in order to form polyene chains therein, and then stretching the film in one direction to unidirectionally orient the polyene chains. Alternatively, the light-polarizing film can be produced by partially dehydrohalogenating 1~27953 halogenated vinyl or vinylidene polymer in the form of a solution in the presence of a basic compound, casting the resulting solution into a film, heating the film until the desired light absorption is observed within the visible light wavelength range, whereby polyene chains are formed, and then stretching the film in one direction to unidirec-tionally orient the polyene chains.
The halogenated vinyl or vinylidene polymer used in the production of the light-polarizing film is a homo-polymer or a copolymer of a monomer of the formula:
~Rl CH2 = C \ (I) X
in which X is halogen (preferably, chlorine or bromine);
Rl is hydrogen, -CN, -COOR2, -OOCR3 or an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.);
R2 is an alkyl group having 1 to 10 carbon atoms; and R3 is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.) or a cycloalkyl group having 5 to 10 carbon atoms (e.g. cyclohexyl, etc.). Typical examples of these polymers are a homopolymer or a copolymer of a vinyl halide and/or a vinylidene halide such as vinyl chloride, vinyl bromide, vinylidene chloride and the like. Further, the halogenated vinyl or vinylidene polymer may be a copolymer of the above monomer (I) and up to 90 mol % (based on all structural units of the polymer) of another copolymerizable monomer, preferably a monomer of the formula:
CH2 = C \ (II) 1~Z7953 in which R4 is hydrogen or an alkyl group having 1 to 10 carbon atoms; R5 is hydrogen, a hydrocarbon group having 1 to 10 carbon atoms, such as an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.) or a cycloalkyl group having 5 to 10 carbon atoms (e.g. cyclohexyl, etc.), a hetero-cyclic group having one or more hetero atoms selected from O, N and S (e.g. furfuryl, thienyl etc.) -CN, -COOR6, -OOCR7, or -OH; R6 is hydrogen or an alkyl group having 1 to 10 carbon atoms; R7 is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.), or a cycloalkyl group having 5 to 10 carbon atoms ~e.g. cyclohexyl etc.) and the alkyl chain of the groups R6 and R7 may be interrupted with O, N or S and the hydrocarbon group of R5 may be substituted with one or more halogens. When using a co-polymer of a vinyl halide and a vinylidene halide and/or one or more other copolymerizable monomers, the copolymer must be in the form of a block copolymer or a graft co-polymer so that polyene chains having a sufficient chain length can be formed, and it is preferable that the average chain length (polymerization degree) of a poly-vinyl halide block or a polyvinylidene halide block in the copolymer be more than 20. When the chain length is less than 20, it is difficult to obtain light-polarizing elements (polyene chains) having sufficient activity within the visible light range. Further, it is preferable that the molar ratio of the vinyl halide or the vinylidene halide to all the structural units of the polymer be 0.1/1 to 1/1, more preferably 0.5/1 to 1/1.
Suitable examples of block copolymers are as follows ~279S3 (they are shown by their monomer structural units wherein "VC" and "VB" stand for vinyl chloride and vinyl bromide, respectively):
VC-vinyl acetate, VC-acrylonitrile, VC-ethylene, VC-propylene, VC-styrene, VC-butadiene, VC-isoprene, VC-vinylidene chloride, VC-acrylic acid, VC-methyl acrylate, VC-methyl methacrylater VC-ethylene trifluoride, VB-vinyl acetate, VB-acrylonitrile, VB-ethylene, VB-pro-pylene, VB-vinylidene chloride, VB-styrene, VB-acrylic acid, VB-methyl acrylate, VB-methyl methacrylate, VC-vinyl acetate-vinyl alcohol, VC-vinylidene chloride-methyl acrylate, VC-vinyl fluoride-ethylene tetrafluoride, VB-styrene-methyl acrylate, ~-chlorovinylbenzene-vinyl-benzene, ~-chloroacrylonitrile-acrylonitrile and -chloro-acrylonitrile-methacrylic acid. Suitable examples of graft copolymers are polyvinyl chloride graft-copolymerized with methyl methacrylate or styrene, polyvinyl bromide graft-copolymerized with styrene and the like.
These polymers or copolymers capable of forming polyene chains can be used alone or in any combination with each other.
If necessary, one or more other polymers and additives, such as a stabilizer, a UV absorbing agent, a dye, an antistatic agent and the like, can be added to the light-polarizing f ilm.
The thickness of the light-polarizing film used in the present invention is not critical ~ut is usually in the range o 1 to 200~, preferably 5 to 50~.
The polyacrylate sheet used in the present invention is a non-oriented sheet produced from an acrylate or methacrylate polymer by a conventional method, such as llZ7953 emulsion casting, solution casting, melt extrusion and the like.
The acrylate or methacrylate polymer used in the present invention is preferably a homopolymer or a co-polymer of a monomer of the formula:
lR8 CH2 = C - COORg (III) in which R8 is hydrogen or an alkyl group having 1 to 10 carbon atoms (preferably hydrogen or methyl); and Rg is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms (e.g.
cyclohexyl, isomenthyl, isobornyl, etc.), an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.), an aralkyl group having 7 to 10 carbon atoms (e.g. benzyl, p-isopropylbenzyl or a heterocyclic group containing one or more hetero atoms selected from O, N and S (e.g. fur-furyl, thienyl etc.), and the alkyl chain of the group Rg may be interrupted with O, N or S and the alkyl or aryl group may be substituted with one or more halogens ~e.g. bromine, etc.). Further, the acrylate or meth-acrylate polymer used in the invention may be a copolymerof the above monomer (III) and up to 5~ mol ~ (based on all the structural units of the polymer) of another copoly-merizable monomer of the formula:
~Rl o CH2 = C \ (IV) Rll in which Rlo is hydrogen or an alkyl group having 1 to 10 carbon atoms (preferably, hydrogen or methyl); and Rll is a hydrocarbon group having 1 to 10 carbon atoms, such as an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms (e.g. phenyl, naphthyl, etc.), or a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms (e.g. cyclohexyl, etc.), a heterocyclic group having one or more hetero atoms selected from O, N and S (e.g. furfuryl, thienyl etc.~, -CN, -OH or -OOCR12; R12 is an alkyl group having 1 to 10 carbon atoms and the alkyl chain of the groups Rll and R12 may be interrupted with o, N, S, or -COO- and the group Rll may be substituted with one or more OH or halogens (e.g. bromine, etc.). Examples of the acrylate or methacrylate polymer are homopolymers such as poly-methyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polymethyl acrylate, polyethyl acrylate and the like; bipolymers such as methyl methacrylate-ethyl methacrylate copolymer, methyl methacrylate-propyl methacrylate copolymer, methyl methacrylate-butyl methacrylate copolymer, ethyl methacrylate-propyl methacrylate copolymer, methyl methacrylate-methyl acrylate copolymer, ethyl methacrylate-methyl acrylate copolymer, methyl methacrylate-ethyl acrylate copolymer, methyl acrylate-methyltriglycol acrylate copolymer, methyl methacrylate-methyltriglycol acrylate copolymer, methyl methacrylate-stearyl acrylate copolymer, methyl methacry-late-stearyl methacrylate copolymer, ethyl methacrylate-ethylacrylate copolymer, methyl methacrylate-butyl acrylate copolymer, methyl methacrylate-propyl acrylate copolymer, methyl methacrylate-2-hydroxyethyl methacrylate copolymer, methyl methacrylate-2-hydroxypropyl methacrylate copol~mer, ethyl methacrylate-2-hydroxyethyl methacrylate copolymer, ethyl methacrylate-2-hydroxypropyl methacrylate copolymer,methyl methacrylate-2-hydroxyethyl acrylate copolymer, methyl methacrylate-2-hydroxypropyl acrylate copolymer, ethyl methacrylate-2-hydroxyethyl acrylate copolymer, ethyl meth-acrylate-2-hydroxypropyl acrylate copolymer, methyl meth-acrylate-tetrahydrofurfuryl acrylate copolymer, methyl methacrylate-tetrahydrofurfuryl methacrylate copolymer, ethyl methacrylate-tetrahydrofurfuryl acrylate copolymer, ethyl methacrylate tetrahydrofurfuryl methacrylate copolymer, methyl methacrylate-benzyl acrylate copolymer, methyl methacrylate-benzyl methacrylate copolymer, methyl meth-acrylate-benzyl acrylate copolymer, methyl methacrylate-phenoxyethyl acrylate copolymer, methyl methacrylate-phenoxy-ethyl methacrylate copolymer, methyl methacrylate-cyclohexyl acrylate copolymer, methyl methacrylate-cyclohexyl meth-acrylate copolymer, methyl methacrylate-glycidyl acrylate copolymer, methyl methacrylate-glycidyl methacrylate copolymer, ethyl methacrylate-tribromophenyl acrylate copolymer,methyl methacrylate-dibromopropyl acrylate copolymer, methyl methacrylate-tropine acrylate copolymer, methyl methacry-late-tropine methacrylate copolymer, methyl acrylate-tropine methacrylate copolymer, ethyl methacrylate-tropine acrylate copolymer, methyl methacrylate-isobornyl methacrylate co-polymer, methyl methacrylate-isobornyl acrylate copolymer, ethyl methacrylate-isobornyl methacrylate copolymer, propyl methacrylate-isobornyl methacrylate copolymer, methyl methacrylate-isomenthyl acrylate copolymer, metyl meth-acrylate-isomenthyl methacrylate copol~mer, ethyl ~eth-acrylate-isomenthyl methacrylate copolymer, methyl acxylate-acrylonitrile copolymer, butyl acrylate-acrylonitrile co-polymer, n-propyl acrylate-acrylonitrile copolymer and the like; and terpolymers such as methy methacrylate-ethyl methacrylate-butyl methacrylate co~olymer, methyl meth-acrylate-ethyl methacrylate-methyl ~crylate copolymer, methyl methacrylate-ethyl methacrylate-methyltriglycol acrylate copolymer, methyl methacrylate-ethyl methacrylate-stearyl acrylate copolymer, methyl methacrylate-ethyl meth-acrylate-stearyl methacrylate copolymer, methyl methacry-late-ethyl methacrylate-tetrahydrofurfuryl acrylate copoly-mer, methyl methacrylate-ethyl methacrylate-tetrahydro-furfuryl methacrylate copolymer, methyl methacrylate-ethyl methacrylate-benzyl acrylate copolymer, methyl methacrylate-ethyl methacrylate-benzyl methacrylate copolymer, methyl methacrylate-ethyl methacrylate-phenoxyethyl acrylate co-polymer, methyl methacrylate-ethyl methacrylate-phenoxyethyl methacrylate copolymer, methyl methacrylate-ethyl meth-acrylate-cyclohexyl acrylate copolymer, methyl methacrylate-ethyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-ethyl methacrylate-glycidyl acrylate copolymer, methyl methacrylate-ethyl methacrylate-glycidyl methacrylate copolymer, methy methacrylate-ethyl methacrylate-tribromo-phenyl acrylate copolymer, methyl methacrylate-ethyl meth-acrylate-tribromophenyl methacrylate copolymer, methyl methacrylate-ethyl methacrylate-dibromophenyl methacrylate copolymer, methyl methacrylate-methyl acrylate-benzyl ~eth-` acrylate copolymer, methyl methacrylate-methyl acrylate-cyclohexyl acrylate copolymer, methyl methacrylate-methyl ~F~, acrylate-glycidyl methacrylate copolymer, methyl methacrylate-methyl acrylate-tribromophenyl methacrylate copolymer and the like. The thickness of the polyacrylate sheet can be varied widely but usually it is in the range of 5 to 10,000~ in order to provide good transparency and workability.
The laminated light-polarizing sheet of the present invention is produced by laminating the polyacrylate sheet on either or both surfaces of the light-polarizing film.
The lamination can be carried out by various methods.
For example, the lamination can be carried out by bonding the polyacrylate sheet to the light-polarizing film with an adhesive. Suitable examples of the adhesive to be used are an urethane adhesive (e.g. Adcoat 503-35 -Trade Mark- produced by Toyo Morton Co., Ltd.), an acrylate adhesive (e.g. SK-Daine lOOA, 701, 902 and 1002 -Trade Marks- produced by Soken Kagaku Co., Ltd.; Rheocoat 1020 -Trade Mark- produced by Rheochemical Co., Ltd.~, a nitrile adhesive (e.g. Cemedaine 210 -Trade Mark- produced by Cemedaine Co., Ltd.) and the like.
When the surface of the polyacrylate sheet is adhesively activated by wetting with a solvent, the lamination can be carried out by wetting the surface of the polyacrylate sheet with a solvent and immediately pressing it on the surface of the light-polarizing film to bond the sheet and the film. For example, when the polyacrylate sheet is made of an alkyl acrylate copolymer which is prepared from predominantly methyl methacrylate or ethyl methacrylate, the sheet can be readi~y wetted with a solvent such as an alcohol, a ketone, an ester or an ether and bonded to the light-polarizing film to obta;n ~127953 one form of laminated light-polarizing sheet of the present invention.
The lamination can also be carried out by melt extruding, injection molding or casting-thermosetting the above acrylate or methacrylate polymer on the surface of the light-polarizing film or heat-bonding the polyacrylate sheet to the light-polarizing film. Particularly when a thick laminated light-polarizing sheet is desired, it is preferable to carry out the lamination by melt extruding, injection molding or casting-thermosetting the acrylate or methacrylate polymer on the surface of the light-polarizing film. These methods are easily controllable and a hard and thick sheet can be obtained in a short time. Moreover, the resulting laminated light-polarizing sheet has good optical uniformity and good mechanical properties since little wrinkling and bubbling are produced by these methods.
The laminated light-polarizing sheet of the present invention can be used as it is in various fields, but it may be laminated on either or both surfaces thereof with another sheet material in order to reinforce the sheet, by which damage of the sheet by external force ~e.g. bending) can be prevented and further the heat deterioration can be reduced.
- Examples of such sheet material are the same or a different ~ind of the above polyacrylate sheets, as well as polyester sheets such as polyethylene terephthalate-isophthalate sheet, polybutylene terephthalate sheet, poly(ethylene-diethylene)terephthalate sheet; a poly-carbonate sheet such as poly(4,4'-diphenylpropane)carbonate sheet; ~ polyamide sheet such as nylon 6 sheet, nylon 66 ~Z7~;3 sheet, nylon 6-nylon 66 sheet, polyxylylene azipamide sheet, a polyolefin sheet such as polyethylene sheet, poly-propylene sheet, polybutene-l sheet; a polyvinyl sheet such as polystyrene sheet, polyvinyl chloride-vinylidene chloride sheet; a cellulose sheet such as c~llulose acetate sheet, cellulose triacetate sheet;
glass and the like. The laminating can be carried out by bonding the sheet material to the surface of the laminated light-polarizing sheet with an adhesive or a pressure sensitive adhesive or by casting a solution or a melt of the above sheet material on the surface of the laminated light-polarizing sheet. Alternatively, the sheet material can be heat-bonded to or injected on the surface of the polyacrylate sheet layer of the laminated light-polarizing sheet.
The laminated light-polarizing sheet thus obtained has light resistance since the polyacrylate sheet has UV
screening properties. However, when an improved light resistance is required in order to prevent photo-deterioration of the laminated light-polarizing sheet, it is preferable to impart light filter properties to the light-polarizing film layer or another layer of the laminated light-polarizing sheet, or if any, the adhesive layer, so that at least one of these layers has a light transmittance of not less than 60 % within the wavelength range of 500 to 800m~ and of not more than 10 ~ within the wavelength range of 230 to 420 m~.
The light filter properties can be provided by treating the polyacrylate sheet in a solution of a yellow dye having a maximum light absorption around 400 m~ and a UV absorber at a temperature from room temperature to the ~1;~7953 softening point of the polymer thereof for several seconds to several tens of minutes, washing with water (or removing a solvent) and then drying. Alternatively, the yellow dye and the W absorber may be admixed with the materials of the polyacrylate sheet, the light-polarizing film or the adhesive before forming the sheet, film or adhesive layer.
Suitable examples of the yellow dye having a maximum light absorption around 400 m~ are a disperse dye such as C.I. Disperse Yellow 17 ~ and the like, a direct dye such as Direct Fast Yellow 5G ~, C.I. Direct Yellow 17 ~, C.I.
Direct Yellow 20 ~ and the like. These dyes can be used alone or in any combination thereof. When the poly-acrylate sheet is treated in a solution, the solution preferably has a concentration of the yellow dye of 0.1 to 5 parts by weight per 100 parts by weight of the solvent.
The UV absorber preferably has a light absorption capacity over a wide wavelength range towards the long wavelengths. Suitable examples of the W absorber are a benzophenone derivative such as 2,2'-dihydroxy-4,4'-di-methoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone and the like. These UV absorbers can be used alone or in any combination thereof. When the polyacrylate sheet is treated in a solution, the solution has preferably a con-centration of the UV absorber of 0.1 to 10 parts by weight - per 1~0 parts by weight of the solvent.
When the yellow dye and the UV absorber are admixed with the materials of the polyacrylate sheet, light-polarizing film or adhesive, the amount of the dye and the UV absorber vary with the thickness of the sheet, film or adhesive layer, but, usually it is preferable to use 0.05 to 5 parts by weight of the dye and 0.05 to 10 parts by weight of the UV absorber per 100 parts by weight of the materials.
Examples of the solvent for the dye and the W
absorber are an alcohol such as methanol, ethanol, butanol and the like; an ether such as methyl cellosolve, ethyl cellosolve, methyl carbitol, ethyl carbitol and the like;
a glycol such as ethylene glycol, diethylene glycol and the like; an ester such as ethyl acetate, methyl acetate and the like.
The laminated light-polarizing sheet of the present invention can be suitably used in the liquid crystal display device of watches, electric computers and other various instruments. The laminated light-polarizing sheet can also be used in other various fields such as sunvisors, displays, interior decorations and the like.
Besides, in the production of liquid crystal displays, it is necessary to bond the laminated light-polarizing sheet of the present invention to a liquid crystal cell, a reflex plate and the like. Therefore, it is convenient to provide a pressure sensitive adhesive layer on either or both surfaces of the laminated light-polarizing sheet and/or a reflex plate on either surface of the laminated light-polarizing sheet. These laminated light-polarizing sheets having pressure sensitive adhesive layers and/or a reflex plate are also included in the scope of the present invention.
Examples of the pressure sensitive adhesive are a natural rubber, a synthetic rubber elastomer, vinyl chloride-vinyl acetate copolymer, polyvinyl alkyl ether, polyalkyl acrylate and the like. Usually, the thickness ~1279s3 of the pressure sensitive adhesive layer is about 5 to about 30~. It is preferable that the surface of the pressure sensitive adhesive layer is covered by a release paper or film.
A thin plate of 10 to 100~ in thickness plated with gold, silver, cooper, aluminum, chrome and the like can be used as the reflex plate. A plastic film having a metal deposited thereon can also be used as the reflex plate.
It is useful to deposit a metal on a plastic film having an uneven surface since the resulting deposited film becomes a non-directional reflex plate. Further, the function as the reflex plate can be provided by depositing a metal, such as aluminum, on either surface of the poly-acrylate sheet of the laminated light-polarizing sheet.
In this case, the thickness of the deposit is about 50 to 3,000 A.
Preferred forms of the invention are described below with reference to the accompanying drawings, in which:
Fig. 1 is a graph showing the light transmittance curve of a laminate obtained in Examplé 3; and Fig. 2 is a cross-sectional view of a laminated light-polarizing sheet.
Examples of the construction of the laminated light-polarizing sheet are as follows (wherein 1 is a light-- polarizing film layer, 2 is an adhesive layer, 3 is a polyacrylate sheet layer, 4 is another transparent sheet material layer, 5 is a pressure sensitive adhesive layer, 6 is a reflex plate layer, and 7 is a release film layer~:
(1) The laminated light-polarizing sheet comprising the light-polarizing film layer and the polyacrylate sheet layer:
~lZ7~5;~
1/3, 3/1/3, 1/2/3, 3/2/1/2/3, 3/2/1/2/4, 4/3/2/1/2/3/4 ~ 2) The laminated light-polarizing sheet comprising the light-polarizing film layer, the polyacrylate sheet layer and the pressure sensitive adhesive layer:
7/5/1/3, 7/5/1/2/3, 7/5/1/2/3/5/7, 7/5/3/1/3, 7/5/3/2/1/2/3, 7/5/3/2/1/2/3/5/7 - 16a -,. .-- ,~ . ', ~,..~
~Z7953 (3) The laminated light-polarizing sheet com-prising the light-polarizing film layer, the polyacr~late sheet layer and the reflex plate la~er:
6/2/1/3, 6/5/1/3, 6/5/1/2/3, 6/2/1/2/3, 6/2/1/3/5/7, 6/5/1/2/3/5/7, 6/2/1/2/3/5/7, 6/5/3/2/1/2/3, 6/2/3/2/1/2~3, 6/5/3/2/1/2/3/5/7, 6/2/3/2/1/2/3/5/7.
The following Examples illustrate the present in-~ention but are not to be constxued as limiting the scope thereof.
Example 1 (a) An adhesi~e solution of the following com-position was coated on one surface of a polyethylene tere-phthalate release film (50~) with a doctor knife (gap:
4/1,000 inch~ and dried on a metal frame at 80C for 2 minutes in a hot-air drying chamber. The coating weight was 12.4 g/m2.
Composition of the adhesive solution Acrylic adhesive (SK-Daine 701) 10 parts by weight Curing agent 0.0022 "
Ethyl acetate 90 "
A polyacrylate sheet produced from methyl metha-crylate-ethyl acrylate copolymer was bonded to the surface of the adhesive layer on the film at 50~C for 2 seconds under a pressure of 2.0 kg/cm2. A~ter removing the release film, a polyene-containing light-polarizing film produced by partial dehydrohalogenation of p~lyvinyl chloride (20 ~ was bonded to the adhesive layer on the polyacrylate sheet at 60C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet (construction: 3/2/1).
(b) The surface of the light-polarizing film layer l~Z7953 of the above-obtained laminated light-polarizing sheet (opposite face to the polyacrylate sheet-bonding surface) was bonded to an adhesiYe layer which is formed on another polyacylate sheet produced by the same procedure in the above (a) at 60C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet, both surfaces of which are laminated with a polyacrylate sheet (construction: 3/2/1/2/3).
(c) A pressure sensitive adhesive layer coyered by a release film was provided on one surface of the laminated light-polarizing sheet obtained in the above (b) in the following manner.
A pressure sensitive adhesive solution of the following composition was coated on one surface of a poly-ethylene terephthalate release film (50 ~) with a doctor knife (gap: 4/1,000 inch) and dried on a metal frame at 80C for 2 minutes in a hot-air drying chamber, by which the pressure sensitive composition was coated in an amount of 11.0 g/m .
Composition of the pressure sensitive adhesive solution Acrylate pressure sensitive adhesive 10 parts by weight (SK-Daine lOOB) Ethyl acetate 26 "
To the surface of the pressure sensitive adhesive layer thus formed was further bonded the laminated light-polarizing sheet produced in the same manner as in the .
above (b) at 60~C for 2 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet (construction: 7/5/3/2/1/2/3).
(d) For comparative purpose, according to the 1~i3 same procedures as in the above (a) to (c), to both surfaces of the polyene-containing light-polarizing film (20 ~) were bonded cellulose triacetate films (Fujitac produced by Fuji Film Co., Ltd., 50 ~) with the above adhesive solution and one surface thereof was provided with a pressure sensitive adhesive layer covered by the release film to obtain a laminated light-polarizing sheet.
These laminated light-polarizing sheets were cut into a piece of 1.5 cm x 2.0 cm and carefully bonded to liquid crystal cells. These cells were allowed to stand at 60C for 20 hours under 90 % RH. The cellulose film-laminated light-polarizing sheet of (d) crazed along the stretching direction of the light-polarizing film layer thereof and bubbles were observed between the cell and the pressure sensitive adhesive layer thereof. To the contrary, the polyacrylate sheet-laminated light-polari~ing sheets of (a) to (c) did not craze and no bubble was observed.
Example 2 A pressure sensitive adhesive solution of the following composition was coated on one surface of a poly-ethylene terephthalate release film (50 ~) and dried at 80C for 2 minutes. The pressure sensitive adhesive com-position was coated in an amount of 11.0 g/cm .
Composition of the pressure sensitive adhesive solution - Acrylate pressure sensitive adhesiYe 10 parts by weight (SK-Daine lOOB) Ethyl acetate 26 "
To the surface of the adhesive layer of the film obtained above ~as bonded the light-polarizing film layer of the laminated light-polarizing sheet obtained in Example - l~Z7953 1 (a) at 60C for 2 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet (construction: 3/2/1/5/7).
The laminated light-polarizing sheet thus obtained had an excellent adhesion workabilit~.
Example 3 (a) An adhesive solution (A) having a light filter activity of the following composition was coated on one surface of a polyethylene terephthalate release film (50 ~) and dried at 60C for 2 minutes. The adhesive solution was coated in an amount of 9.7 g/m2.
Composition of the adhesive solution (A) Urethane adhesive (Adcoat 503-35) ~ 50 parts by weight Yellow dye (C.I. Disperse ~ellow 60) ~ 0.125 "
UV absorber (2,2',4,4'-tetrahydroxy- 1.5 "
benzophenone) Ethyl acetate 25 "
Methyl ethyl ketone 25 "
A polyacrylate sheet produced from methyl metha-crylate-ethyl acrylate copolymer was bonded to the surface of the adhesive layer on the film obtained above at 60C
for 2 seconds under a pressure of 2.0 kg/cm2. The thus obtained laminate had a light transmittance of not less than 35 % within the visible light wavelength range of more than 425 m~ and not more than 10 % within the wavelength range of 230 to 390 m~ as shown in the light transmittance curve of the accompanying Figure 1.
After removing the polyethylene terephthalate release film, to the adhesive layer of the resulting poly-acrylate sheet was bonded a polyene-containing light-polarizing film produced by partial dehydrohalogenation . ,~
~27953 of poly~inyl chloride (20 ~ at 85C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet bonded with a polyacrylate sheet la~er having light filter properties on one surface of the light-polarizing film.
(b) In the same manner as described in the above (a), another polyacrylate sheet having an adhesive layer was formed by using an adhesi~e solution (B~ of the following composition.
Composition of the adhesive solution (B) Urethane adhesive (Adcoat 503-35) 50 parts by weight Methyl ethyl ketone 25 "
Ethyl acetate 25 "
The surface of the light-polarizing film layer of the laminated light-polarizing sheet obtained in (a) was bonded to the surface of the adhesive layer of the polyacrylate sheet obtained above at 60C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet having the polyacrylate sheet layer on both surfaces of the light-polarizing film.
(c) In the same manner as described in Example 1 (c), to the surface of the layer of the adhesive solution (B) of the laminated light-polarizing sheet obtained in the above (b) was provided with a layer of a pressure sensitive adhesive in the following manner.
That is, the same pressure sensitive adhesive solution as used in ~xample 1 (c) was coated on one surface of a polyethylene terephthalate release film L50 ~) with a doctor ~nife (gap: 4/1,000 inch) and dried on a metal frame at 80c for 2 minutes in a hot air drying chamber ~7953 (the coated amount of the pressure sensitiye adhesive:
11. 0 kg/cm2) .
To the surface of the pressure sensitiYe adhesiYe layer thus formed was bonded the laminated light-polarizing sheet obtained in the aboYe (b~ at 60C for 2 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet having light filter properties (construc-tion: 7/5/3/2/1/2/3).
The laminated light-polarizing sheet thus obtained was cut into a piece of 2 cm x 7 cm and bonded to a liquid crystal cell. The cell was allowed to stand at 70C
under 95 % RH and no damage such as crazing was observed even if after lO0 hours. Further, the cell was exposed to a xenon fadeometer for lO0 hours but display performance thereof hardly changed as shown in the following table.
Before exposure After exposure Ho 39 % 42 %
Hgo 17 ~ 21 ~
(Ho is the average percent light transmitted with the polari-zation axes parallel. Hgo is the average percent light transmitted with the polarization axes crossed. The light transmittance was measured within the waYelength range of 400 to 700 m~ at intervals of lO m~.) Example 4 The surface of the light-polarizing film layer of the laminated light-polarizing sheet obtained in Example 3 (a) was bonded to an adhesive layer formed on a cellulose triacetate film (Fujitac produced by Fuji Film Co., Ltd.
50~), said adhesive layer ~eing formed by the same procedure as in Example 3 (a) using the adhesive solution (B), at 60C
11~7953 for 3 seconds under ~ pressu~e of 2.0 k~/c~2 to obtain a laminated light-polarizing sheet having the polyacrylate sheet layer and the cellulose triacetate fil~ layer on each surface of the light-polarizing film ~construction:
3/2/1/2/4). The laminated light-polarizing sheet was allowed to stand at 75C for 10 days under 95 % RH but no crazing and no change were observed.
Example 5 According to the same procedure in Example 1 (a), a polyacrylate sheet layer produced from methyl methacrylate- .
ethyl acrylate copolymer was bonded to a polyene-containing light-polarizing film produced by partial dehydrohalogena-tion of polyvinyl chloride to obtain a laminated light-polarizing sheet (construction: 3/2/1). The surface of the light-polarizing film layer of the laminated light-polariz-ing sheet was bonded to an adhesive layer on an aluminum reflex plate (20u , reflectance: 85 ~) (formed by coating the same adhesive solution as used in Example 1 on the aluminum plate) at 60C for 2 seconds under a pressure of 1.5 kg/cm2 to obtain a laminated light-polarizing sheet having a reflex plate layer (construction: 3/2/1/2/6).
Example 6 The release film of the laminated light-polarizing sheet obtained in Example 2 was removed. An aluminum réflex plate (20 ~, reflectance: 35 ~) washed with acetone at severa. times was pressed onto the pressure sensitive adhesive layer of the laminated light-polarizing sheet at room temperature for 2 seconds under a pressure of 2.0 kg/cm2 `to obtain a laminated light-polarizing sheet having a reflex plate layer (construction: 3/2/1/5/6).
~ . __ llZ7953 Example 7 A polyvinyl chloride was partially dehydro-halogenated to obtain a polyene-containing film. The film was stretched in one direction to obtain a light-polarizing film.
A methyl methacylate-methyl acrylate copolymer (molar ratio of copolymerization: 50 : 50~ was molten and extruded through a slit to obtain a non-oriented sheet of 20 ~ in thickness.
The above-obtained light-polarizing film and the polyacrylate sheet thus obtained were bonded with an acrylate adhesive (SK-Daine lOOOA ~ ) as shown in the accompanying ~igure 2 (which is the cross section of the laminate in which 1 is the light-polarizing film, 2 is the adhesive layer (thickness: 5 ~) and 3 is the polyacrylate sheet layer) to obtain a laminated light-polarizing sheet (construction:
3/2/1/2/3).
The laminated light-polarizing sheet was fixed in a metal frame die and the die was closed with a cover plate. A molten acrylate resin (Delpet ~ , produced by Asahi Kasei Co., Ltd.) was injected into the die through a nozzle of an extruder (produced by Nippon Seiko Co., Ltd.; die being cooled with water, cylinder temperature: 180 to 220C, nozzle temperature: 220C, sum of injection time and curing time: 10 seconds, injection pressure: 100 kg/cm2, back pressure: 20 kg/cm2) to obtain a laminated light-polarizing sheet of 2 mm in thickness (construction: 3/2/1/2/3/4).
The laminated light-polarizing sheet thus obt~ined had an excellent polarization efficiency and a bright field 30 of view. ~ach layer of the sheet had an excellent bond ~ - 24 -1:127953 strength. Further, when the sheet was allowed to stand at 80C under 95 % RH, no damage such as crazing was observed.
Example 8 An acrylate adhesive (SK-Daine 701] was coated on one surface of a polyethylene terephthalate release film with a doctor knife and dried at ~0C for 2 minutes. An poly-acrylate sheet produced from methyl methacrylate-butyl metha-crylate copolymer (m.p. 70C) was bonded to the adhesive layer on the film obtained above at 50C for 2 seconds under a pressure of 2.0 kg/cm . After removing the release film, a polyene-containing light-polarizing film produced form polyvinyl chloride (20~ was bonded to the adhesive layer of the above-obtained polyacrylate sheet at 60C for 5 seconds under a pressure of 2.0 kg/cm2 to obtain a laminated light-polarizing sheet.
The surface of the light-polarizing film layer of the above-obtained laminated light-polarizing sheet was heat-bonded to a hard transparent polyvinyl chloride sheet (500 ~) at 120C for about 10 minutes under a pressure of 60 kg/cm2 to obtain a laminated light-polarizing sheet having excellent polarization efficiency and light transmit-tance (construction: 3/2/1/4).
.. _ . . . . . .
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A laminated light-polarizing sheet compris-ing a light-polarizing film of a halogenated vinyl or vinyli-dene polymer containing polyene chains formed by partial dehydrohalogenation and a film or sheet of an acrylate or methacrylate polymer laminated on at least one surface of the light-polarizing film.
2. A laminated light-polarizing sheet according to Claim 1, wherein the film or sheet is laminated on the surface of the light-polarizing film with an adhesive.
3. A laminated light-polarizing sheet according to Claim 1, wherein the film or sheet is directly laminated on the surface of the light-polarizing film.
4. A laminated light-polarizing sheet according to Claim 1, wherein said sheet has a light transmittance of not less than 60 % within the wavelength range of 500 to 800 mµ and of not more than 10 % within the wavelength range of 230 to 420 mµ.
5. A laminated light-polarizing sheet according to Claim 1, wherein a pressure sensitive adhesive layer covered by a release film is further provided on at least one surface of the laminated light-polarizing sheet.
6. A laminated light-polarizing sheet according to Claim 1, wherein a reflex plate is further laminated on either surface of the laminated light-polarizing sheet.
7. A laminated light-polarizing sheet according to Claim 6, wherein a pressure sensitive adhesive layer covered by a release film is further provided on at least one surface of the laminated light-polarizing sheet.
8. A laminated light-polarizing sheet according to Claim 1, wherein the film or sheet is that of a homo-polymer or a copolymer of a monomer of the formula:
in which R8 is hydrogen or an alkyl group having 1 to 10 carbon atoms; and R9 is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a heterocyclic group containing one or more hetero atoms selected from 0, N and S, and the alkyl chain of the group R9 may be interrupted with 0, N or S and the alkyl or aryl group may be substituted with one or more halogens.
in which R8 is hydrogen or an alkyl group having 1 to 10 carbon atoms; and R9 is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a heterocyclic group containing one or more hetero atoms selected from 0, N and S, and the alkyl chain of the group R9 may be interrupted with 0, N or S and the alkyl or aryl group may be substituted with one or more halogens.
9. A laminated light-polarizing sheet according to Claim 1, wherein the film or sheet is that of a copolymer of the monomer of the formula:
in which R8 is hydrogen or an alkyl group having 1 to 10 carbon atoms; and R9 is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a heterocyclic group containing one or more hetero atoms selected from 0, N and S, and the alkyl chain of the group R9 may be interrupted with 0, N or S and the alkyl or aryl group may be substituted with one or more halogens, and up to 50 mol % (based on all the structural units of the polymer) of another copolymerizable monomer of the formula:
in which R10 is hydrogen or alkyl group having 1 to 10 carbon atoms; and R11 is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms, a heterocyclic group having one or more hetero atoms selected from O, N and S, -CN, -OH or -OOCR12;
R12 is an alkyl having 1 to 10 carbon atoms, and the alkyl chain of the groups R11 and R12 may be inter-rupted with O, N, S, or -COO- and the group R11 may be substituted with one or more OH or halogens.
in which R8 is hydrogen or an alkyl group having 1 to 10 carbon atoms; and R9 is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a heterocyclic group containing one or more hetero atoms selected from 0, N and S, and the alkyl chain of the group R9 may be interrupted with 0, N or S and the alkyl or aryl group may be substituted with one or more halogens, and up to 50 mol % (based on all the structural units of the polymer) of another copolymerizable monomer of the formula:
in which R10 is hydrogen or alkyl group having 1 to 10 carbon atoms; and R11 is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a cycloalkyl or bicycloalkyl group having 5 to 10 carbon atoms, a heterocyclic group having one or more hetero atoms selected from O, N and S, -CN, -OH or -OOCR12;
R12 is an alkyl having 1 to 10 carbon atoms, and the alkyl chain of the groups R11 and R12 may be inter-rupted with O, N, S, or -COO- and the group R11 may be substituted with one or more OH or halogens.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA324,879A CA1127953A (en) | 1979-04-04 | 1979-04-04 | Laminated light-polarizing sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA324,879A CA1127953A (en) | 1979-04-04 | 1979-04-04 | Laminated light-polarizing sheet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1127953A true CA1127953A (en) | 1982-07-20 |
Family
ID=4113921
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA324,879A Expired CA1127953A (en) | 1979-04-04 | 1979-04-04 | Laminated light-polarizing sheet |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1127953A (en) |
-
1979
- 1979-04-04 CA CA324,879A patent/CA1127953A/en not_active Expired
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