The invention relates to a photographic element comprising at least one layer of photosensitive silver halide, a base material wherein said base material comprises at least one bottom sheet of biaxially oriented polymer sheet and deformable tie layer material, wherein said deformable tie layer material yield stress of between 6 and 10 MPa in compression which is less than 10% the yield stress of any of the other layers in the element.

This invention relates to photographic materials. In the preferred form it relates to base materials for photographic prints.
In prior art photographic papers comprising high strength biaxially oriented polypropylene layers, great care needs to be taken in handling the materials after exposure and development of the image. Prior art silver halide photographic papers are sensitive to some compressive forces. Dot matrix printers are commonly used to conveniently add various types of useful data to the opposite side of photographic materials. If sufficient localized force is applied from the back to the opposite side photosensitive layers, permanent surface deformation of the imaging side may create undesirable disturbances to the quality of the normally smooth surface of the image. It has been found that the small diameter (250 micrometers) print heads of some dot matrix printers are accelerated at a rate to impact the printed area to cause local stresses of more than 8 MPa, these have been found to permanently deform the emulsion and imaging side components if not sufficiently cushioned. This is particularly true for special photographic materials described in U.S. Pat. Nos. 5,853,965; 5,866,282; 5,888,643; 5,888,682; 5,888,683; and 5,902,720. These photographic materials include substantial replacement of prior art typical soft, thick polyethylene layers with high modulus oriented polypropylene layers which effectively reduce the cushioning effect when printed on the backside with high pressure dot matrix printers. It would be desirable to have a photographic base material that has a degree of compressibility in a location in the element that will not affect the quality of the imaging side, thus cushioning the pressure sensitive photographic layers. This will provide a photographic base material that has increased resistance to showing the effects of localized forces that may be applied to it on the side opposite the image after exposure and development.
There is a continuing need for photographic base materials that have resistance to compressive load after exposure to create an image that results in fewer defects in the print after development.
It is an object of the invention to provide photographic elements having improved resistance to concentrated backside compressive loads.
It is another object to provide photographic elements with reduced imaging side deformation caused by compressive loads after development.
It is a further object to provide photographic elements that have improved resistance to defects caused by high pressure dot matrix printers.
These and other objects of the invention are accomplished by a photographic element comprising at least one layer of photosensitive silver halide, a base material wherein said base material comprises at least one bottom sheet of biaxially oriented polymer sheet and deformable tie layer material, wherein said deformable tie layer material yield stress of between 6 and 10 MPa in compression which is less than 10% the yield stress of any of the other layers in the element.
The invention provides photographic base materials that have resistance to compressive load after exposure which results in fewer image defects in the print after development.
The invention has numerous advantages over prior practices in the art. The invention provides photographic elements that have less image side surface deformation caused by backside high pressure printing head compression during photofinishing of said elements. The flat surface will, therefore, present a pleasing image in the product without undesirable surface streaks. It will also help to reduce image discoloration caused by damage to pressure sensitive silver halide grains which results in undesirable image errors. These and other advantages will be apparent from the detailed description below.
The terms as used herein, xe2x80x9ctopxe2x80x9d, xe2x80x9cupperxe2x80x9d, xe2x80x9cemulsion sidexe2x80x9d, and xe2x80x9cfacexe2x80x9d mean the side or towards the side of an imaging member bearing the imaging layers. The terms xe2x80x9cbottomxe2x80x9d, xe2x80x9clower sidexe2x80x9d, and xe2x80x9cbackxe2x80x9d mean the side or towards the side of the imaging member opposite from the side bearing the imaging layers or developed image. The term xe2x80x9ctie layerxe2x80x9d as used herein refers to a layer of material that is used to adhere biaxially oriented sheets to a base such as paper, polyester, fabric, or other suitable material for the viewing of images.
The photographic element that provides improved resistance to high pressure forces on the backside comprises at least one silver halide and dye forming coupler containing imaging layer and a cushioning layer below at least one side imaging layer having a deformable tie layer material, wherein said deformable material having a yield stress in compression less than 10% of any of the other layers in the element. The deformable material suitably has a plastic deformation stress of between 6 and 10 MPa. The other image base materials have a plastic deformation of between about 60 and 100 MPa. The most preferred deformable material has plastic deformation stress of 8 MPa and comprises a medium density polyethylene (density 0.926) at least 20 xcexcm thick. Medium density polyethylene is hereby defined as having a density range, before extrusion, of 0.926 to 0.940. Other polyolefin layers having a plastic deformation stress below 10 MPa are also suitable. These may include polyethylene, polypropylene, ethylene-vinyl acetate, polybutylene, polymethylpentene, and polydicyclopentadiene. The cushioned layer, as incorporated in this invention, allows the backside compressive forces to be applied to a deformable layer that, once deformed, reduces the pressure on the silver grains and significantly reducing the deformation of the emulsion and any deformable tie layers on the emulsion side, thereby preventing surface imperfections. It is important that the cushioning layer undergoes an inelastic deformation and does not rebound or recover from the applied load.
The preferred location of deformable layer is below the oriented voided polyolefin sheet and under the photographic emulsion and as far as possible from the emulsion. This location is preferred because the deformable layer is most effective when it is located near the applied pressure. In this situation the force being applied to the emulsion can be more effectively dissipated. It is also possible to either add a second cushioning layer to the bottom side of a photographic element or to use the backside location as the sole cushion layer. Additional improvements may be realized with additional layers on the same side or in combination on the top and bottom sides of the base substrate.
The photographic element containing a biaxially oriented voided polyolefin sheet is normally adhered to a paper base by a lamination process. The preferred embodiment of this invention uses a melt extrudable polyolefin polymer to adhere the sheet to the paper base. Melt extrudable polyolefin polymers are used because of their relative low cost, stability, chemical inertness, and general ease of handling. Depending on the end use of the photographic element, it may be desirable to use a polyester base substrate in place of paper. In this case, a laminated cushion layer is critical because the polyester base has little or no compressibility in the thickness direction, and there is a greater need to have a force reducing layer to minimize pressure induced imperfections.
The sensitivity of a photographic emulsion layer containing silver halide may be impacted by a variety of parameters such as silver grain size, the ratio of silver grains to binder, as well as the addition of chemical addenda.
A deformable layer may also be formed by chemical or physical blowing agents. Typical materials comprise one or more from the list of azodicarbonamide, zeolite or molecular sieves, gases such as nitrogen, carbon dioxide or liquids that turn to gas at atmospheric pressure.
Any suitable biaxially oriented polyolefin sheet may be used for the sheet on the top side of the laminated base used in the invention. Microvoided composite biaxially oriented sheets are preferred and are conveniently manufactured by coextrusion of the core and surface layers, followed by biaxially orientation, whereby voids are formed around void-initiating material contained in the core layer. Such composite sheets may be formed as in U.S. Pat. Nos. 4,377,616; 4,758,462; and 4,632,869.
The core of the preferred composite sheet should be from 15 to 95% of the total thickness of the sheet, preferably from 30 to 85% of the total thickness. The nonvoided skin(s) should thus be from 5 to 85% of the sheet, preferably from 15 to 70% of the thickness.
The density (specific gravity) of the composite sheet, expressed in terms of xe2x80x9cpercent of solid densityxe2x80x9d is calculated as follows:                     Composite                          xe2x80x83                        Sheet                          xe2x80x83                        Density                    Polymer                          xe2x80x83                        Density              xc3x97    100    =      %              xe2x80x83            of              xe2x80x83            Solid              xe2x80x83            Density
Percent solid density should be between 45% and 100%, preferably between 67% and 100%. As the percent solid density becomes less than 67%, the composite sheet becomes less manufacturable due to a drop in tensile strength and it becomes more susceptible to physical damage.
The total thickness of the composite sheet can range from 12 to 100 xcexcm, preferably from 20 to 70 xcexcm. Below 20 xcexcm, the microvoided sheets may not be thick enough to minimize any inherent non-planarity in the support and would be more difficult to manufacture. At thickness higher than 70 xcexcm, little improvement in either surface smoothness or mechanical properties are seen, and so there is little justification for the further increase in cost for extra materials.
The biaxially oriented sheets of the invention preferably have a water vapor permeability that is less than 0.85xc3x9710xe2x88x925 g/mm2/day. This allows faster emulsion hardening, as the laminated support of this invention greatly slows the rate of water vapor transmission from the emulsion layers during coating of the emulsions on the support. The transmission rate is measured by ASTM F1249.
xe2x80x9cVoidxe2x80x9d is used herein to mean devoid of added solid and liquid matter, although it is likely the xe2x80x9cvoidsxe2x80x9d contain gas. The void-initiating particles which remain in the finished packaging sheet core should be from 0.1 to 10 xcexcm in diameter, preferably round in shape, to produce voids of the desired shape and size. The size of the void is also dependent on the degree of orientation in the machine and transverse directions. Ideally, the void would assume a shape which is defined by two opposed and edge contacting concave disks. In other words, the voids tend to have a lens-like or biconvex shape. The voids are oriented so that the two major dimensions are aligned with the machine and transverse directions of the sheet. The Z-direction axis is a minor dimension and is roughly the size of the cross diameter of the voiding particle. The voids generally tend to be closed cells, and thus there is virtually no path open from one side of the voided-core to the other side through which gas or liquid can traverse.
The void-initiating material may be selected from a variety of materials, and should be present in an amount of about 5 to 50% by weight based on the weight of the core matrix polymer. Preferably, the void-initiating material comprises a polymeric material. When a polymeric material is used, it may be a polymer that can be melt-mixed with the polymer from which the core matrix is made and be able to form dispersed spherical particles as the suspension is cooled down. Examples of this would include nylon dispersed in polypropylene, polybutylene terephthalate in polypropylene, or polypropylene dispersed in polyethylene terephthalate. If the polymer is preshaped and blended into the matrix polymer, the important characteristic is the size and shape of the particles. Spheres are preferred and they can be hollow or solid. These spheres may be made from cross-linked polymers which are members selected from the group consisting of an alkenyl aromatic compound having the general formula Arxe2x80x94C(R)xe2x95x90CH2, wherein Ar represents an aromatic hydrocarbon radical, or an aromatic halohydrocarbon radical of the benzene series and R is hydrogen or the methyl radical; acrylate-type monomers include monomers of the formula CH2=C(Rxe2x80x2)xe2x80x94C(O)(OR) wherein R is selected from the group consisting of hydrogen and an alkyl radical containing from about 1 to 12 carbon atoms and Rxe2x80x2 is selected from the group consisting of hydrogen and methyl; copolymers of vinyl chloride and vinylidene chloride, acrylonitrile and vinyl chloride, vinyl bromide, vinyl esters having formula CH2xe2x95x90CH(O)COR, wherein R is an alkyl radical containing from 2 to 18 carbon atoms; acrylic acid, methacrylic acid, itaconic acid, citraconic acid, maleic acid, fumaric acid, oleic acid, vinylbenzoic acid; the synthetic polyester resins which are prepared by reacting terephthalic acid and dialkyl terephthalics or ester-forming derivatives thereof, with a glycol of the series HO(CH2)nOH wherein n is a whole number within the range of 2-10 and having reactive olefinic linkages within the polymer molecule, the above described polyesters which include copolymerized therein up to 20 percent by weight of a second acid or ester thereof having reactive olefinic unsaturation and mixtures thereof, and a cross-linking agent selected from the group consisting of divinylbenzene, diethylene glycol dimethacrylate, diallyl ftimarate, diallyl phthalate and mixtures thereof.
Examples of typical monomers for making the crosslinked polymer include styrene, butyl acrylate, acrylamide, acrylonitrile, methyl methacrylate, ethylene glycol dimethacrylate, vinyl pyridine, vinyl acetate, methyl acrylate, vinylbenzyl chloride, vinylidene chloride, acrylic acid, divinylbenzene, acrylamidomethyl-propane sulfonic acid, vinyl toluene, etc. Preferably, the cross-linked polymer is polystyrene or poly(methyl methacrylate). Most preferably, it is polystyrene and the cross-linking agent is divinylbenzene.
Processes well known in the art yield non-uniformly sized particles, characterized by broad particle size distributions. The resulting beads can be classified by screening the beads spanning the range of the original distribution of sizes. Other processes such as suspension polymerization, limited coalescence, directly yield very uniformly sized particles.
The void-initiating materials may be coated with agents to facilitate voiding. Suitable agents or lubricants include colloidal silica, colloidal alumina, and metal oxides such as tin oxide and aluminum oxide. The preferred agents are colloidal silica and alumina, most preferably, silica. The cross-linked polymer having a coating of an agent may be prepared by procedures well known in the art. For example, conventional suspension polymerization processes wherein the agent is added to the suspension is preferred. As the agent, colloidal silica is preferred.
The void-initiating particles can also be inorganic spheres, including solid or hollow glass spheres, metal or ceramic beads or inorganic particles such as clay, talc, barium sulfate, calcium carbonate. The important thing is that the material does not chemically react with the core matrix polymer to cause one or more of the following problems: (a) alteration of the crystallization kinetics of the matrix polymer, making it difficult to orient, (b) destruction of the core matrix polymer, (c) destruction of the void-initiating particles, (d) adhesion of the void-initiating particles to the matrix polymer, or (e) generation of undesirable reaction products, such as toxic or high color moieties. The void-initiating material should not be photographically active or degrade the performance of the photographic element in which the biaxially oriented polyolefin sheet is utilized.
For the biaxially oriented sheet on the top side toward the emulsion, suitable classes of thermoplastic polymers for the biaxially oriented sheet and the core matrix-polymer of the preferred composite sheet comprise polyolefins.
Suitable polyolefins include polypropylene, polyethylene, polymethylpentene, polystyrene, polybutylene, and mixtures thereof. Polyolefin copolymers, including copolymers of propylene and ethylene such as hexene, butene, and octene are also useful. Polypropylene is preferred, as it is low in cost and has desirable strength properties.
The nonvoided skin layers of the composite sheet can be made of the same polymeric materials as listed above for the core matrix. The composite sheet can be made with skin(s) of the same polymeric material as the core matrix, or it can be made with skin(s) of different polymeric composition than the core matrix. For compatibility, an auxiliary layer can be used to promote adhesion of the skin layer to the core.
Addenda may be added to the core matrix and/or to the skins to improve the whiteness of these sheets. This would include any process which is known in the art including adding a white pigment, such as titanium dioxide, barium sulfate, clay, or calcium carbonate. This would also include adding fluorescing agents which absorb energy in the UV region and emit light largely in the blue region, or other additives which would improve the physical properties of the sheet or the manufacturability of the sheet. For photographic use, a white base with a slight bluish tint is preferred.
The coextrusion, quenching, orienting, and heat setting of these composite sheets may be effected by any process which is known in the art for producing oriented sheet, such as by a flat sheet process or a bubble or tubular process. The flat sheet process involves extruding the blend through a slit die and rapidly quenching the extruded web upon a chilled casting drum so that the core matrix polymer component of the sheet and the skin components(s) are quenched below their glass solidification temperature. The quenched sheet is then biaxially oriented by stretching in mutually perpendicular directions at a temperature above the glass transition temperature, below the melting temperature of the matrix polymers. The sheet may be stretched in one direction and then in a second direction or may be simultaneously stretched in both directions. After the sheet has been stretched, it is heat set by heating to a temperature sufficient to crystallize or anneal the polymers while restraining to some degree the sheet against retraction in both directions of stretching.
The composite sheet, while described as having preferably at least three layers of a microvoided core and a skin layer on each side, may also be provided with additional layers that may serve to change the properties of the biaxially oriented sheet. A different effect may be achieved by additional layers. Such layers might contain tints, antistatic materials, or different void-making materials to produce sheets of unique properties. Biaxially oriented sheets could be formed with surface layers that would provide an improved adhesion, or look to the support and photographic element. The biaxially oriented extrusion could be carried out with as many as 10 or more layers if desired to achieve some particular desired property.
These composite sheets may be coated or treated after the coextrusion and orienting process or between casting and full orientation with any number of coatings which may be used to improve the properties of the sheets including printability, to provide a vapor barrier, to make them heat sealable, or to improve the adhesion to the support or to the photo sensitive layers. Examples of this would be acrylic coatings for printability, coating polyvinylidene chloride for heat seal properties. Further examples include flame, plasma or corona discharge treatment to improve printability or adhesion.
By having at least one nonvoided skin on the microvoided core, the tensile strength of the sheet is increased and makes it more manufacturable. It allows the sheets to be made at wider widths and higher draw ratios than when sheets are made with all layers voided. Coextruding the layers further simplifies the manufacturing process.
The structure of a typical biaxially oriented, sheet of the invention is as follows:
The sheet on the side of the base paper opposite to the emulsion layers may be any suitable sheet. The sheet may or may not be microvoided. It may have the same composition as the sheet on the top side of the paper backing material. Biaxially oriented sheets are conveniently manufactured by coextrusion of the sheet, which may contain several layers, followed by biaxial orientation. Such biaxially oriented sheets are disclosed in, for example, U.S. Pat. No. 4,764,425.
The preferred biaxially oriented sheet is a biaxially oriented polyolefin sheet, most preferably a sheet of polyethylene or polypropylene. The thickness of the biaxially oriented sheet should be from 10 to 150 xcexcm. Below 15 xcexcm, the sheets may not be thick enough to minimize any inherent non-planarity in the support and would be more difficult to manufacture. At thicknesses higher than 70 xcexcm, little improvement in either surface smoothness or mechanical properties are seen, and so there is little justification for the further increase in cost for extra materials.
Suitable classes of thermoplastic polymers for the biaxially oriented sheet include polyolefins, polyesters, polyamides, polycarbonates, cellulosic esters, polystyrene, polyvinyl resins, polysulfonamides, polyethers, polyimides, polyvinylidene fluoride, polyurethanes, polyphenylenesulfides, polytetrafluoroethylene, polyacetals, polysulfonates, polyester ionomers, and polyolefin ionomers. Copolymers and/or mixtures of these polymers can be used.
Suitable polyolefins include polypropylene, polyethylene, polymethylpentene, and mixtures thereof. Polyolefin copolymers, including copolymers of propylene and ethylene such as hexene, butene and octene are also useful. Polypropylenes are preferred because they are low in cost and have good strength and surface properties.
Suitable polyesters include those produced from aromatic, aliphatic or cycloaliphatic dicarboxylic acids of 4-20 carbon atoms and aliphatic or alicyclic glycols having from 2-24 carbon atoms. Examples of suitable dicarboxylic acids include terephthalic, isophthalic, phthalic, naphthalene dicarboxylic acid, succinic, glutaric, adipic, azelaic, sebacic, fumaric, maleic, itaconic, 1,4-cyclohexanedicarboxylic, sodiosulfoisophthalic and mixtures thereof. Examples of suitable glycols include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, 1,4-cyclohexanedimethanol, diethylene glycol, other polyethylene glycols and mixtures thereof. Such polyesters are well known in the art and may be produced by well-known techniques, e.g., those described in U.S. Pat. Nos. 2,465,319 and U.S. Pat. No. 2,901,466. Preferred continuous matrix polyesters are those having repeat units from terephthalic acid or naphthalene dicarboxylic acid and at least one glycol selected from ethylene glycol, 1,4-butanediol and 1,4-cyclohexanedimethanol. Poly(ethylene terephthalate), which may be modified by small amounts of other monomers, is especially preferred. Other suitable polyesters include liquid crystal copolyesters formed by the inclusion of suitable amount of a co-acid component such as stilbene dicarboxylic acid. Examples of such liquid crystal copolyesters are those disclosed in U.S. Pat. Nos. 4,420,607; 4,459,402; and 4,468,510.
Useful polyamides include nylon 6, nylon 66, and mixtures thereof. Copolymers of polyamides are also suitable continuous phase polymers. An example of a useful polycarbonate is bisphenol-A polycarbonate. Cellulosic esters suitable for use as the continuous phase polymer of the composite sheets include cellulose nitrate, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate, and mixtures or copolymers thereof. Useful polyvinyl resins include polyvinyl chloride, poly(vinyl acetal), and mixtures thereof. Copolymers of vinyl resins can also be utilized.
The biaxially oriented sheet on the backside of the laminated base can be made with layers of the same polymeric material, or it can be made with layers of different polymeric composition. For compatibility, an auxiliary layer can be used to promote adhesion of multiple layers.
Addenda may be added to the biaxially oriented backside sheet to improve the whiteness of these sheets. This would include any process which is known in the art including adding a white pigment, such as titanium dioxide, barium sulfate, clay, or calcium carbonate. This would also include adding fluorescing agents which absorb energy in the UV region and emit light largely in the blue region, or other additives which would improve the physical properties of the sheet or the manufacturability of the sheet.
The coextrusion, quenching, orienting, anid heat setting of these biaxially oriented sheets may be effected by any process which is known in the art for producing oriented sheet, such as by a flat sheet process or a bubble or tubular process. The flat sheet process involves extruding or coextruding the blend through a slit die and rapidly quenching the extruded or coextruded web upon a chilled casting drum so that the polymer component(s) of the sheet are quenched below their solidification temperature. The quenched sheet is then biaxially oriented by stretching in mutually perpendicular directions at a temperature above the glass transition temperature of the polymer(s). The sheet may be stretched in one direction and then in a second direction or may be simultaneously stretched in both directions. After the sheet has been stretched, it is heat set by heating to a temperature sufficient to crystallize the polymers while restraining to some degree the sheet against retraction in both directions of stretching.
The biaxially oriented sheet on the backside of the laminated base, while described as having preferably at least one layer, may also be provided with additional layers that may serve to change the properties of the biaxially oriented sheet. A different effect may be achieved by additional layers. Such layers might contain tints, antistatic materials, or slip agents to produce sheets of unique properties. Biaxially oriented sheets could be formed with surface layers that would provide an improved adhesion, or look to the support and photographic element. The biaxially oriented extrusion could be carried out with as many as 10 layers if desired to achieve some particular desired property.
These biaxially oriented sheets may be coated or treated after the coextrusion and orienting process or between casting and full orientation with any number of coatings which may be used to improve the properties of the sheets ncluding printability, to provide a vapor barrier, to make them heat sealable, or to mprove the adhesion to the support or to the photo sensitive layers. Examples of this would be acrylic coatings for printability, coating polyvinylidene chloride for heat seal properties. Further examples include flame, plasma or corona discharge treatment to improve printability or adhesion.
The structure of a typical biaxially oriented sheet that may be laminated to the opposite side of the imaging elements is as follows:
The support to which the microvoided composite sheets and biaxially oriented sheets are laminated for the laminated support of the photosensitive silver halide layer may be a polymeric, a synthetic paper, cloth, woven polymer fibers, or a cellulose fiber paper support, or laminates thereof. The base also may be a microvoided polyethylene terephthalate such as disclosed in U.S. Pat. Nos. 4,912,333; 4,994,312; and 5,055,371.
The preferred support is a photographic grade cellulose fiber paper. When using a cellulose fiber paper support, it is preferable to extrusion laminate the microvoided composite sheets to the base paper using a polyolefin resin. Extrusion laminating is carried out by bringing together the biaxially oriented sheets of the invention and the base paper with application of an adhesive between them followed by their being pressed in a nip such as between two rollers. The adhesive may be applied to either the biaxially oriented sheets or the base paper prior to their being brought into the nip. In a preferred form, the adhesive is applied into the nip simultaneously with the biaxially oriented sheets and the base paper. The adhesive may be any suitable material that does not have a harmful effect upon the photographic element. A preferred material is polyethylene that is melted at the time it is placed into the nip between the paper and the biaxially oriented sheet.
During the lamination process, it is desirable to maintain control of the tension of the biaxially oriented sheets in order to minimize curl in the resulting laminated support. For high humidity applications ( greater than 50% RH) and low humidity applications ( less than 20% RH), it is desirable to laminate both a front side and back side film to keep curl to a minimum.
The surface roughness of this invention can also be accomplished by laminating a biaxially oriented sheet to a paper base that has the desired roughness. The roughness of the paper base can be accomplished by any method known in the art such as a heated impression nip or a press felt combined with a roller nip in which the rough surface is part of the press nip. The preferred roughness of the base paper is from 35 xcexcm to 150 xcexcm. This preferred range is larger than roughness range for the imaging support because of the loss of roughness that occurs in melt extrusion lamination.
In one preferred embodiment, in order to produce photographic elements with a desirable photographic look and feel, it is preferable to use relatively thick paper supports (e.g., at least 120 xcexcm thick, preferably from 120 to 250 xcexcm thick) and relatively thin microvoided composite sheets (e.g., less than 50 xcexcm thick, preferably from 20 to 50 xcexcm thick, more preferably from 30 to 50 xcexcm thick).
As used herein, the phrase xe2x80x9cphotographic elementxe2x80x9d is a material that utilizes photosensitive silver halide in the formation of images. In the case of thermal dye transfer or ink jet, the image layer that is coated on the imaging element may be any material that is known in the art such as gelatin, pigmented latex, polyvinyl alcohol, polycarbonate, polyvinyl pyrrolidone, starch, and methacrylate. The photographic elements can be single color elements or multicolor elements. Multicolor elements contain image dye-forming units sensitive to each of the three primary regions of the spectrum. Each unit can comprise a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art. In an alternative format, the emulsions sensitive to each of the three primary regions of the spectrum can be disposed as a single segmented layer.
The photographic emulsions useful for this invention are generally prepared by precipitating silver halide crystals in a colloidal matrix by methods conventional in the art. The colloid is typically a hydrophilic film forming agent such as gelatin, alginic acid, or derivatives thereof.
The crystals formed in the precipitation step are washed and then chemically and spectrally sensitized by adding spectral sensitizing dyes and chemical sensitizers, and by providing a heating step during which the emulsion temperature is raised, typically from 40xc2x0 C. to 70xc2x0 C., and maintained for a period of time. The precipitation and spectral and chemical sensitization methods utilized in preparing the emulsions employed in the invention can be those methods known in the art.
Chemical sensitization of the emulsion typically employs sensitizers such as: sulfur-containing compounds, e.g., allyl isothiocyanate, sodium thiosulfate and allyl thiourea; reducing agents, e.g., polyamines and stannous salts; noble metal compounds, e.g., gold, platinum; and polymeric agents, e.g., polyalkylene oxides. As described, heat treatment is employed to complete chemical sensitization. Spectral sensitization is effected with a combination of dyes, which are designed for the wavelength range of interest within the visible or infrared spectrum. It is known to add such dyes both before and after heat treatment.
After spectral sensitization, the emulsion is coated on a support. Various coating techniques include dip coating, air knife coating, curtain coating and extrusion coating.
The silver halide emulsions utilized in this invention may be comprised of any halide distribution. Thus, they may be comprised of silver chloride, silver chloroiodide, silver bromide, silver bromochloride, silver chlorobromide, silver iodochloride, silver iodobromide, silver bromoiodochloride, silver chloroiodobromide, silver iodobromochloride, and silver iodochlorobromide emulsions. It is preferred, however, that the emulsions be predominantly silver chloride emulsions. By predominantly silver chloride, it is meant that the grains of the emulsion are greater than about 50 mole percent silver chloride. Preferably, they are greater than about 90 mole percent silver chloride; and optimally greater than about 95 mole percent silver chloride.
The silver halide emulsions can contain grains of any size and morphology. Thus, the grains may take the form of cubes, octahedrons, cubo-octahedrons, or any of the other naturally occurring morphologies of cubic lattice type silver halide grains. Further, the grains may be irregular such as spherical grains or tabular grains. Grains having a tabular or cubic morphology are preferred.
The photographic elements of the invention may utilize emulsions as described in The Theory of the Photographic Process, Fourth Edition, T. H. James, Macmillan Publishing Company, Inc., 1977, pages 151-152. Reduction sensitization has been known to improve the photographic sensitivity of silver halide emulsions. While reduction sensitized silver halide emulsions generally exhibit good photographic speed, they often suffer from undesirable fog and poor storage stability.
Reduction sensitization can be performed intentionally by adding reduction sensitizers, chemicals which reduce silver ions to form metallic silver atoms, or by providing a reducing environment such as high pH (excess hydroxide ion) and/or low pAg (excess silver ion). During precipitation of a silver halide emulsion, unintentional reduction sensitization can occur when, for example, silver nitrate or alkali solutions are added rapidly or with poor mixing to form emulsion grains. Also, precipitation of silver halide emulsions in the presence of ripeners (grain growth modifiers) such as thioethers, selenoethers, thioureas, or ammonia tends to facilitate reduction sensitization.
Examples of reduction sensitizers and environments which may be used during precipitation or spectral/chemical sensitization to reduction sensitize an emulsion include ascorbic acid derivatives; tin compounds; polyamine compounds; and thiourea dioxide-based compounds described in U.S. Pat. Nos, 2,487,850; 2,512,925; and British Patent 789,823. Specific examples of reduction sensitizers or conditions, such as dimethylamineborane, stannous chloride, hydrazine, high pH (pH 8-11) and low pAg (pAg 1-7) ripening are discussed by S. Collier in Photographic Science and Engineering, 23, 113 (1979). Examples of processes for preparing intentionally reduction sensitized silver halide emulsions are described in EP 0 348 934 A1 (Yamashita), EP 0 369 491 (Yamashita), EP 0 371 388 (Ohashi), EP 0 396 424 A1 (Takada), EP 0 404 142 A1 (Yamada), and EP 0 435 355 A1 (Makino).
The photographic elements of this invention may use emulsions doped with Group VIII metals such as iridium, rhodium, osmium, and iron as described in Research Disclosure, September 1996, Item 38957, Section I, published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire PO10 7DQ, ENGLAND. Additionally, a general summary of the use of iridium in the sensitization of silver halide emulsions is contained in Carroll, xe2x80x9cIridium Sensitization: A Literature Review,xe2x80x9d Photographic Science and Engineering, Vol. 24, No. 6, 1980. A method of manufacturing a silver halide emulsion by chemically sensitizing the emulsion in the presence of an iridium salt and a photographic spectral sensitizing dye is described in U.S. Pat. No. 4,693,965. In some cases, when such dopants are incorporated, emulsions show an increased fresh fog and a lower contrast sensitometric curve when processed in the color reversal E-6 process as described in The British Journal of Photography Annual, 1982, pages 201-203.
A typical multicolor photographic element of the invention comprises the invention laminated support bearing a cyan dye image-forming unit comprising at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan dye-forming coupler; a magenta image-forming unit comprising at least one green-sensitive silver halide emulsion layer having associated therewith at least one magenta dye-forming coupler; and a yellow dye image-forming unit comprising at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler. The element may contain additional layers, such as filter layers, interlayers, overcoat layers, subbing layers, and the like. The support of the invention may also be utilized for black and white photographic print elements.
The photographic elements may also contain a transparent magnetic recording layer such as a layer containing magnetic particles on the underside of a transparent support, as in U.S. Pat. Nos. 4,279,945 and 4,302,523. Typically, the element will have a total thickness (excluding the support) of from about 5 to about 30 xcexcm.
In the following Table, reference will be made to (1) Research Disclosure, December 1978, Item 17643, (2) Research Disclosure, December 1989, Item 308119, and (3) Research Disclosure, September 1996, Item 38957, all published by Kenneth Mason Publications, Ltd., Dudley Annex, 12 a North Street, Emsworth, Hampshire PO10 7DQ, ENGLAND. The Table and the references cited in the Table are to be read as describing particular components suitable for use in the elements of the invention. The Table and its cited references also ways of preparing, exposing, processing and manipulating the images contained therein.
The photographic elements can be exposed with various forms of energy which encompass the ultraviolet, visible, and infrared regions of the electromagnetic spectrum as well as with electron beam, beta radiation, gamma radiation, x-ray, alpha particle, neutron radiation, and other forms of corpuscular and wave-like radiant energy in either noncoherent (random phase) forms or coherent (in phase) forms, as produced by lasers. When the photographic elements are intended to be exposed by x-rays, they can include features found in conventional radiographic elements.
The photographic elements are preferably exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image, and then processed to form a visible image, preferably by other than heat treatment. Processing is preferably carried out in the known RA-4(trademark)(Eastman Kodak Company) Process or other processing systems suitable for developing high chloride emulsions.
The laminated substrate of the invention may have copy restriction features incorporated such as disclosed in U.S. Pat. Nos. 5,752,152 and 5,919,730. These applications disclose rendering a document copy restrictive by embedding into the document a pattern of invisible microdots. These microdots are, however, detectable by the electro-optical scanning device of a digital document copier. The pattern of microdots may be incorporated throughout the document. Such documents may also have colored edges or an invisible microdot pattern on the back side to enable users or machines to read and identify the media. The media may take the form of sheets that are capable of bearing an image. Typical of such materials are photographic paper and film materials composed of polyethylene resin coated paper, polyester, (poly)ethylene naphthalate, and cellulose triacetate based materials.
The microdots can take any regular or irregular shape with a size smaller than the maximum size at which individual microdots are perceived sufficiently to decrease the usefulness of the image, and the minimum level is defined by the detection level of the scanning device. The microdots may be distributed in a regular or irregular array with center-to-center spacing controlled to avoid increases in document density. The microdots can be of any hue, brightness, and saturation that does not lead to sufficient detection by casual observation, but preferably of a hue least resolvable by the human eye, yet suitable to conform to the sensitivities of the document scanning device for optimal detection.
In one embodiment the information-bearing document is comprised of a support, an image-forming layer coated on the support and pattern of microdots positioned between the support and the image-forming layer to provide a copy restrictive medium. Incorporation of the microdot pattern into the document medium can be achieved by various printing technologies either before or after production of the original document. The microdots can be composed of any colored substance, although depending on the nature of the document, the colorants may be translucent, transparent, or opaque. It is preferred to locate the microdot pattern on the support layer prior to application of the protective layer, unless the protective layer contains light scattering pigments. Then the microdots should be located above such layers and preferably coated with a protective layer. The microdots can be composed of colorants chosen from image dyes and filter dyes known in the photographic art and dispersed in a binder or carrier used for printing inks or light-sensitive media.
In a preferred embodiment the creation of the microdot pattern as a latent image is possible through appropriate temporal, spatial, and spectral exposure of the photosensitive materials to visible or non-visible wavelengths of electromagnetic radiation. The latent image microdot pattern can be rendered detectable by employing standard photographic chemical processing. The microdots are particularly useful for both color and black-and-white image-forming photographic media. Such photographic media will contain at least one silver halide radiation sensitive layer, although typically such photographic media contain at least three silver halide radiation sensitive layers. It is also possible that such media contain more than one layer sensitive to the same region of radiation. The arrangement of the layers may take any of the forms known to one skilled in the art, as discussed in Research Disclosure 37038 of February 1995.
The following examples illustrate the practice of this invention. They are not intended to be exhaustive of all possible variations of the invention. Parts and percentages are by weight unless otherwise indicated.
A photographic paper support was produced by refining a pulp furnish of 50% bleached hardwood kraft, 25% bleached hardwood sulfite, and 25% bleached softwood sulfite through a double disk refiner, then a Jordan conical refiner to a Canadian Standard Freeness of 200 cc. To the resulting pulp furnish was added 0.2% alkyl ketene dimer, 1.0% cationic cornstarch, 0.5% polyamide-epichlorohydrin, 0.26 anionic polyacrylamide, and 5.0% TiO2 on a dry weight basis. An about 46.5 lbs. per 1000 sq. ft. (ksf) bone dry weight base paper was made on a fourdrinier paper machine, wet pressed to a solid of 42%, and dried to a moisture of 10% using steam-heated dryers achieving a Sheffield Porosity of 160 Sheffield Units and an apparent density 0.70 g/cc. The paper base was then surface sized using a vertical size press with a 10% hydroxyethylated cornstarch solution to achieve a loading of 3.3 wt. % starch. The surface sized support was calendered to an apparent density of 1.04 gm/cc.


An eyeglass device comprised of a primary eyeglass frame and an auxiliary eyeglass frame, each containing lenses therein. The primary eyeglass frame includes a bridge and earpieces, which are connected to extensions on each side of the frame. The bridge may made of a flexible memory alloy, such as NiTi or CuAlBe. The extensions have magnets mounted on the undersides of them. The auxiliary eyeglass frame also includes a bridge and temporal extensions. These extensions have magnets mounted to the tops of them. The magnets engage magnetically with each other to connect the auxiliary eyeglass frame to the primary eyeglass frame. The flexible bridges of the primary and auxiliary eyeglass frames assist in preventing the auxiliary eyeglass frame from becoming dislodged from the primary eyeglass frame in case it jostled by the wearer because they can withstand slight distortion.

The present invention relates to an eyeglass device comprising auxiliary eyeglasses, which are attached to primary eyeglasses by magnetic or mechanical engagement.
With eyeglass clips which are attached by means of conventional attachments, the clips may become disengaged by torsion. As the frame is twisted or turned in any axial, radial or other direction, the clips will become dislodged from the primary frame, thus falling off or, at a minimum, becoming out of alignment and perhaps partially disconnected from the primary frame. To address this problem the rigidity of the primary frame must therefore be balanced, so as not to deform too much when subjected to various types of torsion. This has been true of primary frames used in association with both of magnetic and non-magnetic auxiliary frames. Today, frames are commonly manufactured with more flexible materials.
Another alternative has been to have an auxiliary eyeglass frame made out of extremely flexible material. However, auxiliary frame of this type have the disadvantage of being very fragile.
Various types of auxiliary eyeglass frames which contain magnetic material to facilitate adhesion to the primary eyeglass frame have been disclosed in the prior art. U.S. Pat. No. 4,070,103 discloses an eyeglass frame in which the peripheral edges of the primary frame and lens rim covers contain magnetic strips to hold the lens rim cover in place on the primary frame. U.S. Pat. No. 5,416,537 discloses an eyeglass frame which contains magnetic members on the temple of the primary frame which engage a corresponding magnetic member on the temple of the auxiliary frame. U.S. Pat. No. 5,642,177 discloses an auxiliary eyeglass frame which uses the same principle of magnets on the temporal portions as U.S. Pat. No. 5,416,537; however the auxiliary frame disclosed in U.S. Pat. No. 5,642,177 contains a hinge on the bridge of the frame which allows it to be folded. U.S. Pat. No. 5,568,207 discloses an auxiliary frame which contains small extensions on the temporal portions of the frame which secure the auxiliary frame to the primary eyeglass frame in addition to using the principle of magnetic members as disclosed in U.S. Pat. No. 5,416,537. U.S. Pat. No. 6,012,811 discloses an auxiliary eyeglass frame in which the bridge includes a U-shaped structure having two arms on the top and bottom of the bridge, respectively, with magnets located in respective arms, and the bridge of the primary frame, including its magnetic member, is sandwiched between the two arms.
There are many disadvantages to the eyeglasses described above. The auxiliary eyeglass frame described in U.S. Pat. No. 4,070,103 requires magnetic strips on both the primary and auxiliary frames. The auxiliary eyeglass frame described in U.S. Pat. No. 5,416,537 has the magnets attaching at the top of the primary frame, thus requiring the wearer to be extraordinarily precise in placing the auxiliary frame on the primary frame. The auxiliary eyeglass frame disclosed in U.S. Pat. No. 5,642,177 has front mounted magnets, which may cause the auxiliary frame to separate from the primary frame if jostled by the wearer.
Canadian patent 2,235,798, Canadian application 2,258,142, and U.S. Pat. No. 5,894,335 provide other examples of mechanical and/or magnetic attachment of auxiliary and primary frames.
The primary objective of this present invention is to provide an auxiliary eyeglass frame which securely attaches to a primary eyeglass frame by magnets.
This objective is achieved by a primary and auxiliary eyeglass frame combination comprised of a auxiliary eyeglass frame and a primary eyeglass frame, each containing separate lenses therein. The auxiliary eyeglass frame includes two side portions which are connected by a bridge. Each side portion of the frame has a temporal extension with magnets mounted, preferably, on a top of each extension. The primary eyeglass frame also includes two side portions which are connected by a bridge. The bridges of both the primary and auxiliary frames may be made of a flexible memory alloy, such as NiTi, or CuAlBe similar to that disclosed in U.S. Pat. No. 5,640,217, so that the bridges are more deformable than other parts of the frames. Each side portion has a temporal extension to which temporal members, providing ear pieces, are connected. Each temporal extension also has a magnet mounted, preferably, on an underside of the extension. The auxiliary eyeglass frame is secured to the primary eyeglass frame by the magnetic force between the bottom mounted magnets on the primary frame""s temporal extensions and the top mounted magnets on the auxiliary frame""s temporal extensions. If the bridge of either the primary or auxiliary frame is made of a flexible shape memory alloy, such as NiTi or CuAlBe, it would be less likely that the auxiliary frame will become dislodged if jostled by the wearer because both frames would be able to withstand slight deformation. In other words, a relatively flexible portion linking two more rigid frame parts could deform to absorb an impact on one frame part, preventing the shock being transmitted to the other frame part.
According to another aspect of the invention, magnets may be mounted on one or both frames at any suitable location, such as on one or both bridges, for example, and one or more other, possibly adjacent, locations of one or both frames (where a magnet is not mounted, for example, the temporal extensions or temples), may be made of a flexible shape memory alloy or other suitable flexible material.
Magnetic engagement of primary and auxiliary frame parts may be obtained by provision of cooperating permanent magnets on both frame parts, or by a permanent magnet on only one frame part with a cooperating portion of the other frame part being made of magnetic material functioning as a temporary magnet.
The primary and auxiliary frames may rely for attachment together on magnetic engagement alone, or such magnetic engagement may be supplemented or replaced by mechanical engagement provided, for example, by suitably located clips, pins and sockets or other suitable releasable fastenings, as described in any of the references referred to above, the disclosures of which are incorporated herein by reference.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.


The invention provides personal wash compositions which deposit high levels of sunscreen while maintaining good lather. Enhanced deposition, from bar or liquid, is based on specific sunscreens used, particularly on their solubility.

The invention relates to personal wash compositions which deposit high levels of sunscreen (SPF  greater than 2) while maintaining good lather (i.e., suffer minimal lather degradation over time relative to compositions with more xe2x80x9coilyxe2x80x9d sunscreens). Enhanced deposition is found from both bar and liquid compositions and is based on the solubility or non-solubility of the sunscreen used.
It is a difficult task to deposit significant levels of sunscreen from skin cleansers. Moreover, most sunscreens severely defoam the cleanser composition. Therefore, previous attempts to deliver sunscreen from cleansers resulted in cleanser having low levels of protection (i.e., SPF  less than 2); which had unsatisfactory user properties (e.g., low lather); and which were expensive to make (because of high levels of sunscreen required to obtain effective protection).
One reason deposition has been so difficult to achieve is that most of sunscreens used are either water insoluble oils or insoluble fine solid particles (e.g., ZnO, TiO2). Such sunscreens are generally dispersed into dilute suspensions by surfactants present in the cleanser. As a result, and without wishing to be bound by theory, it is believed that most of the sunscreen will remain suspended, the suspended sunscreen will be removed when skin is rinsed, and little will be left to deposit on the skin. Further, dispersions of the sunscreens into the wash liquid tends to defoam the liquor. In addition, incorporation of oily sunscreen in bars also generally increases softness, stickiness and mush.
Unexpectedly, applicants have found a novel class of sunscreens which can be delivered and provide superior sun protection. These sunscreens can be deposited even in presence of anionic surfactants. Unlike most sunscreens, these are much more soluble in water than the usual xe2x80x9coilyxe2x80x9d sunscreen and provide measurable sun protection even at low levels of addition (e.g., 0.1-15%, preferably 0.5 to 12%, more preferably 1.0 to 10% by wt.). Moreover, since they are more soluble in water, they do not defoam cleanser during wash process.
More specifically, applicants have found specific sunscreen agents which are organic molecules absorbing light in the UV range. These sunscreens are water-soluble UV absorbers (greater than or equal to 0.1% preferably greater than 0.5% water solubility on a weight to weight basis at neutral pH). The sunscreens include a functional group that is anionic or at least part of the sunscreen becomes anionic (e.g., anionic functional group incorporated at sufficiently high pH) at suitable pH (e.g., pH xe2x89xa73, preferably greater than 4, preferably 4 to 10) and the sunscreens are water soluble or become soluble at suitable pH (again about 3 to 10). Examples of such molecules include: phenylbenzimidazole sulphonic acid, anionic salts of said acid which form at pH of 7 and above and mixtures thereof (forming at pH between 4 and 7); ferulic acid, its anionic salts and mixtures thereof; benzophenone-4, its anionic salts and mixtures thereof; and benzophenone-9, its anionic salts and mixtures thereof. Preferably, the sunscreen agents are used in the form of their salts generally at pH 7 and above.
While not wishing to be bound by theory, these anionic organic sunscreen molecules are believed to bind to positively charged sites on proteins within the skin thereby accounting for enhanced deposition. Because molecules deposited through binding from solution cover the surface uniformly, the UV protection is also believed to be more effective than protection obtained from oily or particulate sunscreens where the deposition may be localized to small areas of skin and leave some areas unprotected. Moreover, because the agents are more soluble in water than oily components, they cause less defoaming than the oily or particulate sunscreen agents. As noted above, oily, particulate sunscreens are believed to suspend in surfactants and more readily wash off when rinsed, thereby leading to lower deposition. Oily agents also lead to mushier bars. The specific sunscreen agents of the invention avoid these problems.
Some of the organic sunscreen materials of the invention are not new. For example, WO 14053 to Cussons Int. Ltd. teaches personal wash compositions containing sunscreen agents including phenylbenzimidazole sulphonic acid (which is recited among a list of sunscreen agents which may be used (page 7).
The reference does not recognize that the sulphonic acid sunscreen agent or salts thereof provide superior sun protection relative to other sunscreens including even those used in the reference itself (see Examples 1-3 of reference). The higher water solubility also makes the sunscreens less defoaming and more soluble for personal wash products where foaming is considered a desirable attribute.
U.S. Pat. Nos. 4,933,174 and 4,701,321 by J. Bernstein (assigned to Amethyst Investment Group, Inc.) teaches a liquid PW composition, which comprises nonionic and amphoteric surfactants, and sunscreen materials including aminobenzoic acid, the esters of an aminobenzoic acid, homosalate, 2-hydroxy-4-methoxylbenzophenone (oxybenzone) or 2-ethoxyethyl p-methoxycinnamate (cinoxate). Nonionic and amphoteric surfactants instead of anionic surfactants are used to enhance the deposition of sunscreen agents. Repeated washing and bathing with the compositions leaves a long-lasting layer of sunscreens in the stratum corneum of the skin. The reference fails to recognize that specific anionic sunscreens (e.g., anionic salts) of the invention, particularly when used in systems comprising anionic surfactants, deposit better than other sunscreens.
The noted U.S. patents also do not specifically include phenylbenzimidazole sulphonic acid, benzophenone-4 or any of the other materials suitable for our invention as candidates for the sunscreen agents claimed. These patents further require that formulations contain only nonionic or amphoteric surfactant and further requires that the compositions be used repeatedly over many weeks to achieve the claimed effects.
Unexpectedly, applicants have found that when specific sunscreens and/or their salts are used in personal wash compositions, they are more water soluble than many oily particulate sunscreens normally used (e.g., xe2x80x9cnormalxe2x80x9d oils having solubility of less than 0.1% wt. by wt. water compared to more soluble xe2x80x9csaltsxe2x80x9d of subject invention); they provide enhanced sun protection factor or SPF (e.g. SPF greater than 2, to about 25, preferably greater than 3 to 20, more preferably from about 4 to 15); and the sunscreen does not depress foaming (e.g., foaming does not depress over time compared with more oily components whose lather does depress more quickly over time).
Generally, using the sunscreens of invention, foaming does not depress more than about 50%, preferably more than 30%, preferably more than about 25% over 30 minutes time using test as defined in examples.
More specifically, the present invention provides a personal wash composition, particularly personal wash compositions which may be in bar or liquid form. In one embodiment the compositions are bars comprising:
(1) 20% to 85% by wt of first anionic surfactant which may be fatty acid soap or a synthetic anionic;
(2) 0-25%, preferably 1-20% second surfactant selected from the group consisting of second anionic surfactant (different from first), nonionic, amphoteric, cationic and mixture thereof;
(3) 0-15% free fatty acid;
(4) 0-20% water soluble structurant (e.g., polyalkylene glycol, EO-PO copolymers);
(5) 0 to 40%, preferably 0-35% alkanoate (e.g., glycerol monostearate) having chain length of C12 to C24; and
(6) 0.1 to 10% of a sunscreen agent, anionic salt (e.g., functional group attached to sunscreen agent which, in solution, yields negative charge such as, for example, sulfates, sulfonates, carboxylates, phosphates, phosphonates, etc.), or mixtures thereof (at least some portion of the sunscreen must be in its salt form; however, this is inherently accomplished by specifying minimum pH values);
wherein sunscreen agent (by which is meant overall equilibrium of the acid form of the sunscreen, its salt and mixtures) has a water solubility of greater than or equal to 0.1%, preferably greater than 0.5% on weight to weight basis as measured at pH 7;
wherein said sunscreen has SPF of greater than 2 to 25; and
wherein composition does not degrade more than 50% lather, preferably no more than 35%, more preferably no more than 25% over 30 minutes as defined in examples.
Bars generally will have 1-15%, preferably 2-12% water.
In a second embodiment, composition may be liquid composition comprising:
(1) 10-80% anionic surfactant;
(2) 0-25% of second surfactant selected from group consisting of anionic different from first, nonionic, amphoteric/zwifterionic, cationic and mixtures thereof; and
(3) 0.1 to 10% of a sunscreen agent, salt thereof or mixtures as defined above;
wherein sunscreen agent has a water solubility of greater than or equal to 0.1%, preferably greater than 0.5% on weight to weight basis as measured at pH 7;
wherein said sunscreen has SPF of greater than 2 to 25; and
wherein composition does not degrade more than 50% lather, preferably no more than 35%, more preferably no more than 25% over 30 minutes as defined in examples.
The present invention is based on applicants unexpected finding that certain sunscreen agents and/or salts thereof are anionic, water-soluble compounds which provide enhanced SPF while simultaneously not depressing foam relative to more oily, less water soluble sunscreen compounds (e.g., those which are generally less soluble and have solubility of less than 0.5% wt. for wt. water). These xe2x80x9cmorexe2x80x9d water-soluble sunscreen agents and/or anionic salts thereof (counterions may exist to anionic group as well) provide unexpectedly enhanced effect whether used in bar or liquid cleanser compositions.
In one embodiment, the invention comprises bar compositions comprising:
(1) 20 to 85% by wt. of a first anionic surfactant which is fatty acid soap or synthetic anionic;
(2) 0 to 25% by wt. of a second surfactant selected from the group consisting of a second anionic (differing from the first), nonionic surfactant, amphoteric/zwitterionic surfactant, cationic surfactant and mixtures thereof;
(3) 0 to 15% by wt. free fatty acid (particularly where bar is a predominantly fatty acid soap bar);
(4) 0 to 20% of a water-soluble structurant which is neither soap nor non-soap detergent and has MW in the range 40 to 100xc2x0 C. (e.g., polyalkylene glycol EO-PO copolymers);
(5) 0 to 40% glycerol monoalkanoate of C12-C24 chain length; and
(6) 0.1 to 10% of a sunscreen agent and/or salt thereof (providing anionic charge) wherein sunscreen and/or salt thereof has SPF greater than 2 to 25, preferably greater than 3 to 20, more preferably greater than about 4 to 15;
wherein sunscreen agent and/or salt has solubility of greater than or equal to 0.1%, preferably greater than 0.5% on weight to weight basis as measured neutral pH; and
wherein sunscreen agent and/or salt has lather which does not substantially degrade over time relative to more oily components.
In second embodiment of the invention, compositions may be liquid cleanser comprising:
(1) 10-80% first anionic surfactant; and
(2) 0 to 25% second surfactant selected from the group consisting of anionic different from first, nonionic, amphoteric/zwitterionic, cationic and mixtures thereof;
(3) 0.1 to 10% of sunscreen and/or salt thereof as defined with bar compositions thereof; and
(4) balance water,
wherein compositions has SPF values, solubility and lather parameters as defined for bar compositions above.
Each of these embodiments is described in more detail below.
First Anionic
The first anionic surfactant may be a synthetic surfactant or fatty acid soap. Although not preferred, the bar compositions may comprise a xe2x80x9cpurexe2x80x9d soap composition. Such bars are generally not mild (although they do foam well and have sensory properties preferred by some consumers) and so it is generally preferred to use bars which are predominantly synthetic or which are combinations of synthetic and soap.
The term xe2x80x9csoapxe2x80x9d is used here in its popular sense, i.e., the alkali metal or alkanol ammonium salts of aliphatic alkane- or alkene monocarboxylic acids. Sodium, potassium, mono-, di and tri-ethanol ammonium cations, or combinations thereof, are suitable for purposes of this invention. In general, sodium soaps are used in the compositions of this invention, but from about 1% to about 25% of the soap may be potassium soaps. The soaps useful herein are the well known alkali metal salts of natural or synthetic aliphatic (alkanoic or alkanoic) acids having about 12 to 22 carbon atoms, preferably about 12 to about 18 carbon atoms. They may be described as alkali metal carboxylates of acrylic hydrocarbons having about 12 to about 22 carbon atoms.
Soaps having the fatty acid distribution of coconut oil may provide the lower end of the broad molecular weight range. Those soaps having the fatty acid distribution of peanut or rapeseed oil, or their hydrogenated derivatives may provide the upper end of the broad molecular weight range.
It is preferred to use soaps having the fatty acid distribution of coconut oil or tallow, or mixtures thereof, since these are among the more readily available fats. The proportion of fatty acids having at least 12 carbon atoms in coconut oil soap is about 85%. The proportion will be greater when mixtures of coconut oil and fats such as tallow, palm oil or non-tropical nut oils or fats are used, wherein the principle chain lengths are C16 and higher. Preferred soap for use in the compositions of this invention has at least about 85% fatty acids having about 12-18 carbon atoms.
Coconut oil employed for the soap may be substituted in whole or in part by other xe2x80x9chigh-lauricxe2x80x9d oils, that is, oils or fats wherein at least 50% of the total fatty acids are composed of lauric or myristic acids and mixtures thereof. These oils are general exemplified by the tropical nut oils of the coconut oil class. For instance, they include: palm kernel oil, babassu oil, ouricuri oil, tucum oil, cohune nut oil, muru-muru oil, jaboty kernel oil, khakan kernel oil, dika nut oil, and ucuhuba butter.
A preferred soap is a mixture of about 15% to about 20% coconut oil and about 80% to about 85% tallow. These mixtures contain about 95% fatty acids having about 12 to about 18 carbon atoms. The soap may be prepared from coconut oil in which case the fatty acid content is about 85% of C12-C18 chain length.
The soaps may contain unsaturation in accordance with commercially acceptable standards. Excessive unsaturation is normally avoided.
Soaps may be made by the classic kettle boiling process or modern continuous soap manufacturing processes wherein natural fats and oils such as tallow or coconut oil or their equivalents are saponified with an alkali metal hydroxide using procedures well known to those skilled in the art. Alternatively, the soaps may be made by neutralizing fatty acids, such as lauric (C12), myristic (C14), palmitic (C16) or staric (C18) acids with an alkali metal hydroxide or carbonate.
The first anionic detergent active which may be used may be aliphatic sulfonates, such as a primary alkane (e.g., C8-C22) sulfonate, primary alkane (e.g., C8-C22) disulfonate, C8-C22 alkene sulfonate, C8-C22 hydroxy alkane sulfonate or alkyl glycerol ether sulfonate (AGS); or aromatic sulfonates such as alkyl benzene sulfonate.
The first anionic may also be an alkyl sulfate (e.g., C12-C18 alkylsulfate) or alkyl ether sulfate (including alkyl glycerol ether sulfates). Among the alkyl ether sulfates are those having the formula:
RO(CH2(CH2xe2x80x94O)nSO3M
wherein R is an alkyl or alkenyl having 8 to 18 carbons, preferably 12 to 18 carbons; n has an average value of greater than 1.0, preferably greater than 3: and M is a solubilizing cation such as sodium, potassium ammonium or substituted ammonium. Ammonium and sodium lauryl ether sulfates are preferred.
The anionic may also be alkyl sulfosuccinates (including mono- and dialkyl, e.g., C6-C22 sulfosuccinates); alkyl and acyl taurates, alkyl and acyl sarcosinates, sulfoacetates, C8-C22 alkyl phosphates and phosphates, alkyl phosphate esters and alkoxyl alkyl phosphate esters, acyl lactates, C8-C22 monoalkyl succinates and maleates, sulphoacetates, alkyl glycosides and acyl isethionates.
Sulfosuccinates may be monoalkyl sulfosuccinates having the formula:
R4O2CCH2CH(SO3M)CO2M;
and amide-MEA sulfosuccinates of the formula
R4CONHCH2CH2O2CCH2CH(SO3M)CO2M
wherein R4 ranges from C8-C22 alkyl and M is a solubilizing cation.
Sarcosinates are generally indicated by the formula
RCON(CH3)CH2CO2M,
wherein R ranges from C8-C20 alkyl and M is a solubilizing cation.
Taurates are generally identified by formula:
R2CONR3CH2CH2SO3M
wherein R2 ranges from C8-C20 alkyl, R3 ranges from C1-C4 alkyl and M is a solubilizing cation.
Particularly preferred are the C8-C18 acyl isethionates. These esters are prepared by reaction between alkali metal isethionate with mixed aliphatic fatty acids having from 6 to 18 carbon atoms and an iodine value of less than 20. At least 75% of the mixed fatty acids have from 12 to 18 carbon atoms and up to 25% have from 6 to 10 carbon atoms.
Acyl isethionates, when present, will generally range from about 10% to about 70% by weight of the total composition. Preferably, this component is present from about 30% to about 60%.
The acyl isethionate may be an alkoxylated isethionate such as is described in Ilardi et al., U.S. Ser. No. 796,748, hereby incorporated by reference. This compound has the general formula:
wherein R is an alkyl group having 8 to 18 carbons, m is an integer from 1 to 4, X and Y are hydrogen or an alkyl group having 1 to 4 carbons and M+ is a monovelent cation such as, for example, sodium, potassium or ammonium.
In general the anionic component will comprise from about 10 to 70% of the composition, preferably 20-50% by wt. of the composition.
Second Surfactant
The second surfactant may be any of the anionics defined above except that it differs from the first anionic. The second component may also be any of the amphoteric or nonionics discussed below as well as a mixture of the anionic, amphoteric and/or nonionic.
Amphoteric detergents which may be used in this invention include at least one acid group. This may be a carboxylic or a sulphonic acid group. They include quaternary nitrogen and therefore are quaternary amido acids. They should generally include an alkyl or alkenyl group of 7 to 18 carbon atoms. They will usually comply with an overall structural formula:
wherein
R1 is alkyl or alkenyl of 7 to 18 carbon atoms: R2 and R3 are each independently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 3 carbon atoms;
m is 2 to 4;
n is 0 to 1
X is alkylene of to 3 carbon atoms optionally substituted with hydroxyl, and
Y is xe2x80x94CO2xe2x80x94 or xe2x80x94SO3xe2x80x94
Suitable amphoteric detergents within the above general formula include simple betaines of formula:
and amido betaines of formula:
where m is 2 or 3;
In both formulae R1, R2 and R3 are as defined previously. R1 may in particular be a mixture of C12 and C14 alkyl groups derived from coconut so that at least half, preferably at least three quarters of the groups R1 have 10 to 14 carbon atoms. R2 and R3 are preferably methyl.
A further possibility is that the amphoteric detergent is a sulphobetaine of formula:
where m is 2 or 3, or variants of these in which xe2x80x94(CH2)3SO3xe2x80x94 is replaced by:
In these formula R1, R2 and R3 are as discussed previously.
The nonionic which may be used as the second component of the invention include in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are alkyl (C6-C22) phenols-ethylene oxide condensates, the condensation products of aliphatic (C8-C18) primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called nonionic detergent compounds include long chain tertiary amine oxides, long chain tertiary phosphine oxides and dialkyl sulphoxides.
The nonionic may also be a sugar amide, such as a polysaccharide amide. Specifically, the surfactant may be one of the lactobionamides described in U.S. Ser. No. 816,419 to Au et al. which is hereby incorporated by reference or it may be one of the sugar amides described in U.S. Pat. No. 5,009,814 to Kelkenberg, hereby incorporated into the subject application by reference.
Other surfactants which may be used are described in U.S. Pat. No. 3,723,325 to Parran Jr., which is also incorporated into the subject application by reference.
In general the second component (i.e., second anionic nonionic and/or amphoteric compound or mixture) is incorporated into the composition as less than 20% by weight, preferably 1 to 15% by weight of the composition.
Structurant
In general, bars of the invention may comprise 0 to 75% structurant (e.g., free fatty acid, water soluble structurant, glycerol monoalkanoate noted below). Preferably, the bar will contain 5% to 65% structurant though none is required.
Free Fatty Acid
Free fatty acids of 8-22 carbon atoms may also be desirably incorporated within the compositions of the present invention. Some of these fatty acids are present to operate as superfatting agents and others as skin feel and creaminess enhancers. Superfatting agents enhance lathering properties and may be selected from fatty acids of carbon atoms numbering 8-18, preferably 10-16, generally in an amount up to 15% by weight (although higher amounts may be used) of the composition. Skin feel and creaminess enhancers, the most important of which is stearic acid, are also desirably present in these compositions.
Water Soluble Structurant
Another compound which may be used in the bar is water soluble structurant (e.g., polyalkylene glycol).
This component should comprise 0% by wt. to 60%, preferably greater than 5% to 40% by wt. of the bar composition.
The structurant (e.g., polyalkylene glycol) has a melting point of 40xc2x0 C. to 100xc2x0 C., preferably 45xc2x0 C. to 100xc2x0 C., more preferably 50xc2x0 C. to 90xc2x0 C.
Materials which are envisaged as the water soluble structurant (b) are moderately high molecular weight polyalkylene oxides of appropriate melting point and in particular polyethylene glycols or mixtures thereof.
Polyethylene glycols (PEG""s) which may be used may have a molecular weight in the range 1,500-20,000.
It should be understood that each product (e.g., Union Carbide""s Carbowax(copyright) PEG 8,000) represents a distribution of molecular weights. Thus PEG 8,000, for example, has an average MW range of 7,000-9,000, while PEG 300 has an average MW range from 285 to 315. The average MW of the product can be anywhere between the low and high value, and there may still be a good portion of the material with MW below the low value and above the high value.
In some embodiments of this invention it is preferred to include a fairly small quantity of polyalkylene glycol (e.g., polyethylene glycol) with a molecular weight in the range from 50,000 to 50,000, especially molecular weights of around 100,000. Such polyethylene glycols have been found to improve the wear rate of the bars. It is believed that this is because their long polymer chains remain entangled even when the bar composition is wetted during use.
If such high molecular weight polyethylene glycols (or any other water soluble high molecular weight polyalkylene oxides) are used, the quantity is preferably from 1% to 5%, more preferably from 1% or 1.5% to 4% or 4.5% by weight of the composition. These materials will generally be used jointly with a larger quantity of other water soluble structurant (b) such as the above mentioned polyethylene glycol of molecular weight 1,500 to 10,000.
Some polyethylene oxide polypropylene oxide block copolymers melt at temperatures in the required range of 40xc2x0 C. to 100xc2x0 C., and may be used as part or all of the water soluble structurant (b). Preferred ere are block copolymers in which polyethylene oxide provides at least 40% by weight of the block copolymer. Such block copolymers may be used in mixtures with polyethylene glycol or other polyethylene glycol water soluble structurant.
Glycerol Monoalkanoate
Another optional structurant which may be used is glycerol monoalkanoate wherein alkanoate group may be C12-C24 alkyl (e.g., glycerol monostearate). This may comprise 0-60% by wt. of bar, preferably 5% to 50% by wt.
Sunscreen
The sunscreens of the invention are defined by the fact that they are sunscreens which form salts (at sufficient pH) so that the salts or an equilibrium of salt and the acid form of the sunscreen have a solubility of greater than 0.1% wt/wt., preferably greater than 0.5% as measured at neutral pH. As noted, in general the pH of the composition has to be high enough to have at least some portion of the anionic salt.
The anionic salts are formed by functional anionic groups well known to those skilled in the art such as sulphates, sulfonates, carboxylates, phosphates, phosphonates and other groups which are well known to provide anionic charges in solution.
Unexpectedly, applicants have found that use of these sunscreens and/or salts which have the defined solubility will provide enhanced SPF (e.g., 2 to 25) relative to other sunscreens while at the same time not depressing the lather function of the final composition.
Examples of such sunscreen compounds include phenylbenzimidazole sulphonic acid and salts thereof; ferulic acid and salts thereof; benzophenone and its salts thereof. Other examples include variants of benzophenone and salts thereof.
Other Compounds
Skin mildness improvers also preferably used in the composition of the invention are salts of isethionate. Effective salts cations may be selected from the group consisting of alkali metal, alkaline earth metal, ammonium, alkyl ammonium and mono-, di or tri-alkanolammonium ions. Specifically preferred cations include sodium potassium, lithium, calcium, magnesium, ammonium, triethylammonium, monoethanolammonium, diethanolammonium or triethanolammonium ions.
Particularly preferred as a mildness improver is simple unsubstituted sodium isethionate.
The skin mildness improver will be present from about 0.5% to about 50%. Preferably, the mildness improver is present from about 1% to about 25%, more preferably from about 2% to about 15, optimally from 3% to 10% by weight of the total composition.
Other performance chemicals and adjuncts may be needed with these compositions. The amount of these chemicals and adjuncts may range from about 1% to about 40% by weight of the total composition. For instance, from 2 to 10% of a suds-busing detergent salt may be incorporated. Illustrative of this type additive are salts selected from the group consisting of alkali metal and organic amine higher aliphatic fatty alcohol sulfates, alkyl aryl sulfonates and the higher aliphatic fatty acid taurinates.
Adjunct materials including germicides, perfumes, colorants, pigments such as titanium dioxide and water may also be present.
The bar compositions of the invention have SPF of greater than 2 to 25, preferably greater than about 3 to 20 and more preferably greater than about 4 to 15.
SPF is defined as per the protocol in the example section.
In addition compositions have lather of which does not degrade more than 50%, preferably more than 35%, preferably more than 25% over 30 minute period.
In a second embodiment, the compositions of the invention may also be liquid compositions as noted above.
Liquid
First Anionic
In the liquid compositions, the first anionic surfactant may be any of the surfactants as for the bars above except that it will not be xe2x80x9csoapxe2x80x9d as defined therein.
Second Surfactant
The second surfactant may also be one of the above as defined for bars.
Optional
The liquids of this invention may be isotropic single phase liquids or they may be structured as defined and using structurants as defined in U.S. Pat. No. 5,952,286 to Puvvada et al. hereby incorporated by reference into the subject invention.
The compositions may contain oils or emollients as noted below.
Vegetable oils: Arachis oil, castor oil, cocoa butter, coconut oil, corn oil, cotton seed oil, olive oil, palm kernel oil, rapeseed oil, safflower seed oil, sesame seed oil and soybean oil.
Esters: Butyl myristate, cetyl palmitate, decyloleate, glyceryl laurate, glyceryl ricinoleate, glyceryl stearate, glyceryl isostearate, hexyl laurate, isobutyl palmitate, isocetyl stearate, isopropyl isostearate, isopropyl laurate, isopropyl linoleate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, propylene glycol monolaurate, propylene glycol ricinoleate, propylene glycol stearate, and propylene glycol isostearate.
Animal Fats: Acytylatelte lanolin alcohols, lanolin, lard, mink oil and tallow.
Fatty acids and alcohols: Behenic acid, palmitic acid, stearic acid, behenyl alcohol, cetyl alcohol, eicosanyl alcohol and isocetyl alcohol.
Other examples of oil/emollients include mineral oil, petrolatum, silicone oil such as dimethyl polysiloxane, lauryl and myristyl lactate.
It should be understood that where the emollient may also function as a structurant, it should not be doubly included such that, for example, if the structurant is 15% oleyl alcohol, no more than 5% oleyl alcohol as xe2x80x9cemollientxe2x80x9d would be added since the emollient (whether functioning as emollient or structurant) never comprises more than 20%, preferably no more than 15% of the composition.
The emollient/oil is generally used in an amount from about 1 to 20%, preferably 1 to 15% by wt. of the composition. Generally, it should comprise no more than 20% of the composition.
In addition, the compositions of the invention may include optional ingredients as follows:
Organic solvents, such as ethanol; auxiliary thickeners, such as carboxymethylcellulose, magnesium aluminum silicate, hydroxyethylcellulose, methylcellulose, carbopols, glucamides, or Antil(copyright) from Rhone Poulenc; perfumes; sequestering agents, such as tetrasodium ethylenediaminetetraacetate (EDTA), EHDP or mixtures in an amount of 0.01 to 1%, preferably 0.01 to 0.05%; and coloring agents, opacifiers and pearlizers such as zinc stearate, magnesium stearate, TiO2, EGMS (ethylene glycol monostearate) or Lytron 621 (Styrene/Acrylate copolymer); all of which are useful in enhancing the appearance or cosmetic properties of the product.
The compositions may further comprise antimicrobials such as 2-hydroxy-4,2xe2x80x24xe2x80x2 trichlorodiphenylether (DP300); preservatives such as dimethyloldimethylhydantoin (Glydant XL1000), parabens, sorbic acid etc.
The compositions may also comprise coconut acyl mono- or diethanol amides as suds boosters, and strongly ionizing salts such as sodium chloride and sodium sulfate may also be used to advantage.
Antioxidants such as, for example, butylated hydroxytoluene (BHT) may be used advantageously in amounts of about 0.01% or higher if appropriate.
Cationic conditioners which may be used include Quatrisoft LM-200 Polyquaternium-24, Merquat Plus 3330xe2x80x94Polyquaternium 39; and Jaguar(copyright) type conditioners.
Polyethylene glycols which may be used include:
Thickeners which may be used include Amerchol Polymer HM 1500 (Nonoxynyl Hydroethyl Cellulose); Glucam DOE 120 (PEG 120 Methyl Glucose Dioleate); Rewoderm(copyright) (PEG modified glyceryl cocoate, palmate or tallowate) from Rewo Chemicals; Antil(copyright) 141 (from Goldschmidt).
Another optional ingredient which may be added are the defloculating polymers such as are taught in U.S. Pat. No. 5,147,576 to Montague, hereby incorporated by reference.
Another ingredient which may be included are exfoliants such as polyoxyethylene beads, walnut sheets and apricot seeds.
The liquid compositions, like the bar compositions will have SPF values and lather volume as defined for the bars.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts or ratios of materials or conditions or reaction, physical properties of materials and/or use are to be understood as modified by the word xe2x80x9caboutxe2x80x9d.
Where used in the specification, the term xe2x80x9ccomprisingxe2x80x9d is intended to include the presence of stated features, integers, steps, components, but not to preclude the presence or addition of one or more features, integers, steps, components or groups thereof.
The following examples are intended to further illustrate the invention and are not intended to limit the invention in any way.
Unless indicated otherwise, all percentages are intended to be percentages by weight.

Personal wash sunscreen compositions which deposit and lather well

Unilever Home and Personal Care USA division of Conopco, Inc.