Photopolymerizable compositions and elements for refractive index imaging

Claim 2

A substantially solid, photopolymerizable composition that forms a refractive-index image upon exposure to actinic radiation as the sole processing step, said composition consisting essentially of: (a) 25 to 75% of a solvent soluble, thermoplastic polymeric binder; (b) 5 to 60% of a liquid ethylenically unsaturated monomer, said monomer having a boiling point above 100° C and being capable of addition polymerization; (c) 0.1 to 10% of a a photoinitiator system that activates polymerization of said unsaturated monomer upon exposure to actinic radiation; wherein said percentages are weight percentages of the total binder, unsaturated monomer and photoinitiator system of components (a), (b), and (c), the composition having a refractive index modulation of at least 0.005 as determined with 632.8 nm radiation from a transmission grating having a spatial frequency of about 1000 lines per millimeter, which transmission grating is prepared holographically from a layer of said composition.

Claim 3

The composition of claim 1 wherein either said binder or said unsaturated monomer contains a substituent from the group consisting of phenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic containing up to three aromatic rings, chlorine, bromine, and mixtures thereof, and the other component is substantially free of said substituent.

Claim 4

The composition of claim 2 wherein the unsaturated monomer contains said substituent and wherein the polymeric binder is substantially free of said substituent.

Claim 5

The composition of claim 3 wherein said unsaturated monomer is a phenoxyalkyl acrylate or methacrylate, a phenol ethoxylate acrylate or methacrylate, a phenyl alkyl acrylate or methacrylate, 2-(1-naphthyloxy)ethyl acrylate, the di(2-acryloxyethyl)ether of bisphenol-A, or ethoxylated bisphenol-A diacrylate, and wherein said polymeric binder is a cellulose acetate butyrate; an acrylate or methacrylate polymer or interpolymer; a vinyl butyral, acetal or formal polymer or interpolymer, or a vinyl acetate polymer or interpolymer.

Claim 6

The composition of claim 2 wherein the polymeric binder contains segments having said substituent and wherein the unsaturated monomer is substantially free of said substituents.

Claim 7

The composition of claim 5 wherein the polymeric binder is a styrene polymer or interpolymer, and wherein the unsaturated monomer is an alkylene glycol diacrylate or dimethacrylate, an acrylated or methacrylated polyol ester, or ethoxylated polyol acrylate or methacrylate esters.

Claim 8

The composition of claim 1 in which a solid ethylenically unsaturated monomer is also present.

Claim 9

The composition of claim 7 in which the solid ethylenically unsaturated monomer contains a carbazole group.

Claim 10

The composition of claim 8 wherein said ethylenically unsaturated monomer is selected from the group consisting of N-vinyl carbazole. 3,6-dibromo-9-vinyl carbazole, and mixtures thereof.

Claim 11

The composition of claim 7 wherein the solid ethylenically unsaturated monomer is selected from the group consisting of 2,4,6-tribromophenyl acrylate or methacrylate, pentachlorophenyl acrylate of methacrylate, 2-naphthyl acrylate or methacrylate, 2-(2-naphthyloxy)ethyl acrylate or methacrylate, the di-(2-acryloxyethyl)ether of tetrabromo-bisphenol A, and mixtures thereof.

Claim 12

The composition of claim 1 in which a plasticizer is also present, which plasticizer is selected from the group consisting of tris(2-ethylhexyl)phosphate, glyceryl tributyrate, and a compound having the general formula: wherein R· and R 2 each is an alkyl group of 1 to 10 carbon atoms, R 3 is H or an alkyl group of 8 to 16 carbon atoms, R4- is H or CH 3 , x is 1-4, y is 2-20, and z is 1-20.

Claim 13

The composition of claim 11 wherein the plasticizer is selected from the group consisting of triethylene glycol dicaprylate, triethylene glycol bis(2-ethylhexanoate), diethyl adipate, dibutyl adipate, tetraethylene glycol diheptanoate, dibutyl suberate, diethyl sebacate, tris(2-ethylhexyl)phosphate, and glyceryl tributyrate.

Claim 14

The composition of claim 11 in which said plasticizer is substituted for at least a portion of the liquid ethylenically unsaturated monomer.

Claim 15

A substantially solid, photopolymerizable composition that forms a refractive-index image upon exposure to actinic radiation as the sole processing step, said composition consisting essentially of: (a) 25 to 75% of a solvent-soluble thermoplastic polymeric binder; (b) 5 to 60% of a liquid ethylenically unsaturated monomer, said monomer having a boiling point above 100°C and being capable of addition polymerization; and c) 0.1 to 10% of a photoinitiator system that activates polymerization of said unsaturated monomer upon exposure to actinic radiation; wherein said percentages are weight percentages of the total binder, unsaturated monomer and photoinitiator system of components (a), (b) and (c), with the proviso that either said binder or said unsaturated monomer contains a substituent selected from the group consisting of phenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic containing up to three aromatic rings, chlorine, and bromine.

Claim 16

A substantially solid, photopolymerizable composition that forms a refractive-index image upon exposure to actinic radiation as the sole processing step, said composition consisting essentially of: (a) 25 to 75% of a solvent-soluble thermoplastic polymeric binder; (b) 5 to 60% of a liquid ethylenically unsaturated monomer, said monomer having a boiling point above 100°C and being capable of addition polymerization; and c) 0.1 to 10% of a photoinitiator system that activates polymerization of said unsaturated monomer upon exposure to actinic radiation; wherein said percentages are weight percentages of the total binder, unsaturated monomer and photoinitiator system of components (a), (b) and (c), with the proviso that either said binder or said unsaturated monomer contains a substituent selected from the group consisting of phenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic containing up to three aromatic rings, chlorine, and bromine.

Claim 17

The composition of claim 14 having a refractive index modulation of at least 0.005 as determined with 632.8 nm radiation from a transmission grating having a spatial frequency of about 1000 lines per millimeter, which transmission grating is prepared holographically from a layer of said composition.

Claim 18

A photosensitive element for preparing a refractive-index image by exposure to actinic radiation as the sole processing step, said element comprising a substrate that supports a substantially solid, photopolymerizable composition consisting essentially of: (a) 25 to 75% of a solvent-soluble thermoplastic polymeric binder; (b) 5 to 60% of a liquid ethylenically unsaturated monomer, said monomer having a boiling point above 100 C and being capable of addition polymerization and (c) 0.1 to 10% of a photoinitiator system that activates polymerization of said unsaturated monomer upon exposure to actinic radiation; wherein said percentages are weight percentages of the total binder, unsaturated monomer and photoinitiator system of components (a), (b) and (c), the composition having a refractive index modulation of at least 0.005 as determined with 632.8 nm radiation from a transmission grating having a spatial frequency of about 1000 lines per millimeter, which transmission grating is prepared holographically from a layer of said composition.

Claim 19

A photosensitive element for preparing a refractive-index image by exposure to actinic radiation as the sole processing step, said element comprising a substrate that supports a substantially solid, photopolymerizable composition consisting essentially of: (a) 25 to 75% of a solvent-soluble thermoplastic polymeric binder; (b) 5 to 60% of a liquid ethylenically unsaturated monomer, said monomer having a boiling point above 100 C and being capable of addition polymerization and (c) 0.1 to 10% of a photoinitiator system that activates polymerization of said unsaturated monomer upon exposure to actinic radiation; wherein said percentages are weight percentages of the total binder, unsaturated monomer and photoinitiator system of components (a), (b) and (c), the composition having a refractive index modulation of at least 0.005 as determined with 632.8 nm radiation from a transmission grating having a spatial frequency of about 1000 lines per millimeter, which transmission grating is prepared holographically from a layer of said composition.

Claim 20

1 7. The photosensitive element of claim 16 wherein either said binder or said unsaturated monomer contains a substituent from the group consisting of phenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic containing up to three aromatic rings, chlorine, bromine, and mixtures thereof, and the other component is substantially free of said substituent.

Claim 21

The photosensitive element of claim 16 in which a solid, ethylenically unsaturated monomer is also present in said solid photopolymerizable composition.

Claim 22

The photosensitive element of claim 16 in which a plasticizer is also present in said solid photopolymerizable composition, which plasticizer is selected from the group consisting of tris(2-ethylhexyl)phosphate, glyceryl tributyrate, and a compound having the general formula: wherein R 1 and R 2 each is an alkyl group of 1 to 10 carbon atoms, R 3 is H or an alkyl group of 8 to 16 carbon atoms, R4 is H or CH 3 , x is 1-4, y is 2-20, and z is 1-20.

Claim 23

The photosensitive element of claim 16 wherein the photopolymerizable composition is permanently adhered to a support.

Claim 24

The photosensitive element of claim 16 wherein a protective coversheet is releasably adhered to a surface of the photopolymerizable composition.

Claim 25

The photosensitive element of claim 16 wherein the substrate is transparent to actinic radiation.

Claim 26

The photosensitive element of claim 16 wherein the substrate is transparent to visible radiation.

Claim 27

The photosensitive element of claim 16 wherein the photopolymerizable composition is releasably adhered to the substrate.

Claim 28

The photosensitive element of claim 24 wherein a protective coversheet is releasably adhered to a surface of the photopolymerizable composition, and wherein the adhesive force between the substrate and the photosensitive composition is greater than the adhesion force between the photopolymerizable composition and the protective coversheet.

Claim 29

The photosensitive element of claim 21 or 25 wherein the substrate and protective coversheets are flexible webs.

Claim 30

A process for forming a light-stable hologram in a photopolymerizable layer on a substrate surface comprising in either order: A) exposing to modulated actinic radiation bearing holographic information a photopolymerizable element comprising a sheet support and releasably adhered thereto a photopolymerizable layer comprising: a) a solvent soluble, thermoplastic polymeric material, b) at least one liquid ethylenically unsaturated monomer capable of addition polymerization having a boiling point above 100 C, and c) a photoinitiator system activatable by the actinic radiation, wherein the composition has a refractive index modulation of at least 0.005 as determined with 632.8 nm radiation from a transmission grating having a spatial frequency of about 1000 lines per millimeter prepared holographically from a later of said composition, and wherein the modulated actinic radiation bearing holographic information is formed by interaction of a reference beam of coherent actinic radiation with an image modulated beam of the same coherent actinic radiation and wherein a plane in the intersection corresponds to the plane of the photopolymerizable B) laminating the surface of the photopolymerizable layer to the substrate surface, and then C) removing the sheet support from the exposed photopolymer layer.

Claim 31

A process for forming a light-stable hologram in a photopolymerizable layer on a substrate surface comprising in either order: A) exposing to modulated actinic radiation bearing holographic information a photopolymerizable element comprising a sheet support and releasably adhered thereto a photopolymerizable layer comprising: a) a solvent soluble, thermoplastic polymeric material, b) at least one liquid ethylenically unsaturated monomer capable of addition polymerization having a boiling point above 100 C, and c) a photoinitiator system activatable by the actinic radiation, wherein the composition has a refractive index modulation of at least 0.005 as determined with 632.8 nm radiation from a transmission grating having a spatial frequency of about 1000 lines per millimeter prepared holographically from a later of said composition, and wherein the modulated actinic radiation bearing holographic information is formed by interaction of a reference beam of coherent actinic radiation with an image modulated beam of the same coherent actinic radiation and wherein a plane in the intersection corresponds to the plane of the photopolymerizable B) laminating the surface of the photopolymerizable layer to the substrate surface, and then C) removing the sheet support from the exposed photopolymer layer.

Claim 32

A process of claim 27 wherein steps A, B, and C are repeated one or more times to form a multilayer holographic record.

Claim 33

A process of claim 27 wherein the reference beam and image modulated beam enter the same side of the photopolymerizable layer to form a transmission hologram.

Claim 34

A process of claim 27 wherein the reference beam enters one side of the photopolymerizable layer and the image modulated beam enters the other side of the photopolymerizable to form a reflection hologram.

Claim 35

A process of claim 27 wherein the substrate surface is reflective.

Claim 36

A one-step process for forming a light-stable reflection hologram in a photopolymerizable element which comprises (A) a support sheet transparent to actinic radiation and (B) a layer of photopolymerizable, substantially solid composition adhered to the support sheet wherein the composition comprises a) a solvent soluble, thermoplastic polymeric material, b) at least one liquid ethylenically unsaturated monomer capable of addition polymerization having a boiling point above 100° C, and c) a photoinitiator system activatable by the actinic radiation, wherein the composition has a refractive index modulation of at least 0.005 as determined with 632.8 nm radiation from a transmission grating having a spatial frequency of about 1000 lines per millimeter prepared holographically from a layer of said composition, the process comprising exposing the photopolymerizable element to modulated actinic radiation bearing holographic information wherein the modulated actinic radiation is formed by intersection of a reference beam of coherent actinic radiation with an image modulated beam of the same coherent actinic radiation at a plane corresponding to th plane of the photopolymerizable layer wherein the reference beam enters one side of the photopolymerizable layer and the image modulated enters the reverse side of the photopolymerizable layer.

Claim 37

A one-step process for forming a light-stable reflection hologram in a photopolymerizable element which comprises (A) a support sheet transparent to actinic radiation and (B) a layer of photopolymerizable, substantially solid composition adhered to the support sheet wherein the composition comprises a) a solvent soluble, thermoplastic polymeric material, b) at least one liquid ethylenically unsaturated monomer capable of addition polymerization having a boiling point above 100° C, and c) a photoinitiator system activatable by the actinic radiation, wherein the composition has a refractive index modulation of at least 0.005 as determined with 632.8 nm radiation from a transmission grating having a spatial frequency of about 1000 lines per millimeter prepared holographically from a layer of said composition, the process comprising exposing the photopolymerizable element to modulated actinic radiation bearing holographic information wherein the modulated actinic radiation is formed by intersection of a reference beam of coherent actinic radiation with an image modulated beam of the same coherent actinic radiation at a plane corresponding to th plane of the photopolymerizable layer wherein the reference beam enters one side of the photopolymerizable layer and the image modulated enters the reverse side of the photopolymerizable layer.

Claim 38

A process of claim 32 wherein the image modulated beam is formed from coherent radiation of the reference beam which is transmitted through the photopolymerizable element to illuminate an object and generate an image modulated beam back through the photopolymerizable element and coaxial to the reference beam.

Claim 39

A process of claim 33 wherein the object is a reflection hologram.

Claim 40

A process of claim 32 wherein the liquid monomer contains one or more phenyl, phenoxy, naphthyl, naphthyloxy, or heteroaromatic group containing three or fewer aromatic rings or a chloro or bromo atom and wherein the polymeric material is substantially free of said groups of atoms.

Claim 41

A process of claim 32 wherein the polymeric material contains one or more phenyl, phenoxy, naphthyl, naphthyloxy, or heteroaromatic group containing three or fewer aromatic rings or a chloro or bromo atom and wherein the liquid monomer is substantially free of said groups or atoms.

Claim 42

A process of claim 32 wherein the liquid monomer is a substituted or unsubstituted phenoxy alkyl acrylate or methacrylate; a substituted or unsubstituted phenol ethoxylate acrylate or methacrylate; or a substituted or unsubstituted phenyl alkyl acrylate or methacrylate; 2-(1-naphthyloxy)ethyl acrylate; the di(2-acryloxyethyl)ethyl of bisphenol-A; or ethoxylated bisphenol-A diacrylate; and wherein the solvent soluble, thermoplastic, polymeric material is a cellulose acetate butyrate; an polyacrylate or methacrylate or interpolymer; a polyvinyl butyral, acetal or formal or interpolymer; or a polyvinyl acetate or interpolymer.