Polaroid Corporation

Polaroid Corporation, Patent Dept.

William C Schwarzel

Rong-Chang Liang

Lloyd D Taylor

Maurice J Fitzgerald

Frederick R Kearney

Daoshen Bi

Rong C Liang

Chieh-Min Cheng

Avinash C Mehta

F Richard Cottrell

Roger A Boggs

Jayprakash C Bhatt

Anthony C Giudice

Tung Feng Yeh

Leonard C Wan

John B Mahoney

Tung-Feng Yeh

John C Warner

John M Hardin

Charles I Sullivan

Michael A Young

Stanley J Jasne

Robert P Short

Donna J Guarrera

Stephen R Sofen

Rita S Shon Baker

An imaging medium comprises a substrate carrying a color-change layer. This color-change layer comprises two layers or phases comprising two color-forming reagents which react upon heating to cause a change in the color of the layer. The color-change layer is deactivated by exposure to actinic radiation such that after deactivation it no longer undergoes its thermal color-change. The color-change layer is detachable from the substrate by heating to a temperature lower than required to cause the color change, so that upon contact of the imaging medium with a receiving sheet each individual pixel of the color-change layer may be left attached to the substrate, transferred to the receiving sheet but left uncolored, or transferred to the receiving sheet and colored to a color level determined by the energy used in the associated thermal print head element. The medium may be imaged by imagewise heating, followed by blanket exposure to deactivating actinic radiation, or by imagewise exposure to the actinic radiation, followed by heating of the whole color-change layer.

Heat and radiation-sensitive imaging medium, and processes for use thereof

Heat and radiation-sensitive imaging medium, and processes for use

The present invention discloses the use of rubber and surfactant to enhance the durability and resolution of on-press developable lithographic printing plates. The rubber is preferably incorporated into a photoresist as discrete particulate rubber. To ensure a uniform and stable dispersion, the rubber is suspended in the photoresist by means of a surfactant having an HLB approximately between 7.0 and 18.0.

Lithographic plate with disperse particulate rubber additive

Lithographic printing plates with dispersed rubber additives

The present invention provides a lithographic printing plate comprising a substrate and a photocurable polymeric photoresist, such as those based on free-radical initiated photocuring mechanisms. To constrain detrimental and undesired activity of excess free radicals, an embodiment of the printing plate is further provided with a free-radical regulating system. In a particular embodiment, the free-radical regulating system is provided as an overcoat, the overcoat being a light-transmissive overcoat and comprising a polymer having a pendant free-radical trapping group. A particular polymer for the overcoat has the formula ##STR1## wherein, m is from approximately 20% by weight to approximately 95% by weight, and n is from approximately 0% by weight to approximately 75% by weight. Capable of deactivating free-radicals actinically generated in the photoresist subsequent to exposure, the polymer is soluble in fountain or ink solution and incompatible with the photoresist.

Photoreaction quenchers in on-press developable lithographic printing

The present invention sets forth the incorporation of a substituted 2-phenyl-4,6-bis (trichloromethyl)-1,3,5-triazine in photoresists of lithographic printing plates for the purpose of promoting their shelf-life, room light stability, and developability. The present invention provides a photocurable composition comprising at least a photopolymerizable ethylenically unsaturated monomer having at least one terminal ethylenic group and capable of forming a polymer upon exposure to actinic radiation; and an s-triazine capable of initiating free radical polymerization of the photopolymerizable ethylenically unsaturated monomer and being represented by the following general formula [I]: ##STR1## wherein R.sub.1 is either OR.sub.4 or NR.sub.5 R.sub.6, wherein R.sub.5 and R.sub.6 may or may not be identical with each other, either R.sub.5 or R.sub.6 may represent hydrogen, and wherein R.sub.4 and at least one of R.sub.5 and R.sub.6 represent a ballast group capable of preventing the substantial volatilization of the s-triazine from the photoresist composition, the ballast group being a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, the substituted or unsubstituted alkyl group having at least 4 carbon atoms, the substituted or unsubstituted aryl group having at least 6 carbon atoms; R.sub.2 and R.sub.3 may or may not be identical with each other and each represent hydrogen, halogen, phenyl, a substituted or unsubstituted alkyl group, or an alkoxyl group; X and Y may or may not be identical with each other and each represent chlorine or bromine; and m and n may or may not be identical with each other and are each an integer of 0, 1, or 2. Desirable compositions will further comprise at least one photooxidizable leuco triarylmethane dye.

Low-volatility, substituted 2-phenyl-4,6-bis (halomethyl)-1,3,5-triazine

A photoreactive binder that may be used to enhance photospeed in either conventional plates or on-press developable lithographic printing plates. Briefly, a polymer of m-isopropenyl-.alpha.,.alpha.-dimethylbenzyl isocyanate is derivatized for vinyl group reactivity by reacting the isocyanate groups thereof with hydroxyalkyl acrylate. The resulting photopolymeric binder provides significantly higher photospeed than the non-reactive binder currently utilized in the production of conventional printing plates. The resulting lithographic printing plate also shows better durability (as manifested by longer run-length) and is more easily developed by the microencapsulated developers utilized in the present invention. As to the preparation of the photoreactive binders, the application discloses a method of copolymerizing m-isopropenyl-.alpha.,.alpha.-dimethylbenzyl isocyanate (m-TMI) through complexation with an electron-deficient monomer such as maleic anhydride to accelerate free radical copolymerization with other monomers, and thus, provides greater monomer-to-polymer conversion. Use of the resulting product in the photoresist of a lithographic printing plate improves its adhesion to an underlying substrate.

Synthesis of photoreactive polymeric binders

The addition, to a thermal imaging medium comprising a color-forming compound which undergoes a change of color upon heating above a color-forming temperature for a color-forming time, the color-forming

Stabilization of thermal images

There is described a photographic system wherein development of an exposed photosensitive element with an aqueous alkaline photographic developing composition is effected in the presence of a compound represented by the formula ##STR1## wherein R is --OH, --OR.sub.4, --NH.sub.2 --NHR.sub.5 or --NR.sub.4 R.sub.6 ; R.sub.1 is hydrogen, --NH.sub.2, alkyl, substituted alkyl, aryl or substituted aryl; R.sub.2 and R.sub.3 each independently is hydrogen, alkyl, aralkyl or aryl; R.sub.4 is a protecting group which can be removed in the presence of a base; R.sub.5 is an activating group which can render the neighboring hydrogen atom acidic; R.sub.6 is an electron withdrawing group which is capable of stabilizing the negative charge on the nitrogen atom which is produced upon removal of R.sub.4 upon contact with alkali; and PHOTO is a photographically useful group. The compounds provide controlled release of the photographically useful group by a base-catalyzed elimination when contacted by the aqueous alkaline processing composition.

Photographic compounds

There is described a photographic system wherein development of an exposed photosensitive element with an aqueous alkaline photographic developing composition is effected in the presence of a compound represented by the formula ##STR1## wherein R is --OH, --OR.sub.4, --NH.sub.2 --NHR.sub.5 or --NR.sub.4 R.sub.6 ; R.sub.1 is hydrogen, --NH.sub.2, alkyl, substituted alkyl, aryl or substituted aryl; R.sub.2 and R.sub.3 each independently is hydrogen, alkyl, aralkyl or aryl; R.sub.4 is a protecting group which can be removed in the presence of a base; R.sub.5 is an activating group which can render the neighboring hydrogen atom acidic; R.sub.6 is an electron withdrawing group which is capable of stabilizing the negative charge on the nitrogen atom which is produced upon removal of R.sub.4 upon contact with alkali; and PHOTO is a photographically useful group. The compounds provide controlled release of the photographically useful group by a base-catalyzed elimination when contacted by the aqueous aklaline processing composition.

Photographic system utilizing a compound capable of providing controlled

Photographic diffusion transfer film units including polymeric diffusion control layers are disclosed. The diffusion control layers comprise polymers which are hydrolyzable in an alkaline medium so as to convert a layer comprising one or more of the polymers from a condition of impermeability to alkali or materials soluble in or solubilized by an aqueous alkaline processing composition to a condition of substantial permeability thereto.

Hydrolyzable diffusion control layers in photographic products

A diffusion control layer for a diffusion transfer photographic film unit comprising a urethane polymer including recurring backbone units capable of undergoing .beta.-elimination degradation in an alkaline environment.

Diffusion control layers for diffusion transfer photographic film

Photosensitive elements for color diffusion transfer film units comprising a support layer, at least two selectively-sensitized silver halide layers having image-dye forming materials associated therewith, and a novel interlayer, separating the silver halide layers, comprising a polymeric hydroxamic acid polyvalent metal salt which serves as a barrier to the migration of solubilized image-dye forming material until it is rendered permeable to the image-dye forming material subsequent to contact with a sequestering agent for the polyvalent metal of the salt barrier.

Growing community of inventors

Billerica, MA, United States of America

William C Schwarzel