Minnesota Mining and Manufacturing Company

Roger W Lange

Harold G Sowman

Thomas Edward Wood

James P Mathers

Kathleen M Humpal

Alek P Szecsy

David C May

Thomas P Hedblom

Kyung H Moh

Kathleen A Hachey

Chris J Goodbrake

Arthur Mendel

Thomas E Forester

Mark R Holzer

Soon-Kun Kang

All-ceramic retroreflective elements which may be used in pavement markings comprising an opacified ceramic core and ceramic optical elements partially embedded into the core.

Durable retroreflective elements

An article suitable for use in bonding to metal, glass, or ceramic substrates at high temperatures, e.g., above about 400.degree. C, comprises (a) a thermally stable backing material, such as a metal foil or an inorganic fabric; and (b) a coating on at least a portion of at least one major surface of the backing material, the coating consisting essentially of fused or fusible particles selected from glass particles, ceramic particles, and mixtures thereof. Preferably, the coating further contains a non-pressure sensitive adhesive vehicle such as pine oil, to aid in application and retention of the particles.

High temperature label

Solid, transparent, non-vitreous, microspheres (zirconia-silica) are formed by extractive gelation (extracting carboxylic acid away from zirconyl carboxylate) of a sol in liquid medium such as hot peanut oil. Zirconyl carboxylate precursor sol is prepared and added in droplet form to the liquid extractant (peanut oil) at an elevated temperature at which a carboxylic acid is liberated from the zirconyl carboxylate. The droplets remain in the extractant for sufficient time to form stable gel spheroids which are separated from the extractant and fired to convert them to durable spheroids useful as lens elements in retroreflective sheeting.

Thermal extractive gelation process

A coated article having a substrate coated with a layer of silica particles is provided. The coating is substantially uniform in thickness, adheres aggressively to the substrate, and provides excellent antireflection properties to the substrate.

Silica coating

Solid, transparent, non-vitreous, zirconia and zirconia-silica ceramic microspheres, useful as lens elements in retroreflective pavement markings. The microspheres are characterized by:

Transparent non-vitreous zirconia microspheres

Pavement marking comprising ceramic microspheres held by a binder, said microspheres being solid, transparent, non-vitreous, ceramic particles which serve as lens elements in the retroreflective pavement markings. The ceramic microspheres formed by various sol gel techniques are characterized by having:

Pavement markings containing transparent non-vitreous ceramic

Solid, transparent, non-vitreous, ceramic particles useful as lens elements in retroreflective pavement markings characterized by having:

Transparent non-vitreous ceramic particulate

Primer compositions for adhering overcoatings derived from in situ polymerizations of uncured monomers onto inorganic substrates are disclosed. These primer compositions comprise at least one non-amino- or non-amido-containing silane, at least one of certain metal esters, and preferably an acidic material. The overcoatings are derived from epoxy and vinyl monomers. The primed and overcoated substrates of the present invention provide articles having protective, decorative, or other functional surface layers.

Primed inorganic substrates overcoated with curable protective

Solid, shaped and fired refractory articles, such as fibers and microspheres, of titanium dioxide are made by shaping, gelling, and firing titania sols. Said fibers can be made by extruding in air a viscous aqueous titania sol, and heating and firing the resulting green fiber to remove water, decompose and volatilize undesired constituents, and form a refractory fiber of polycrystalline titanium dioxide, which is useful, for example, to form refractory fabrics or as reinforcement for composites. Said microspheres can be made by dispersing droplets of an aqueous titania sol in an organic dehydrating liquid, separating the resulting green microspheres from the dehydrating liquid, and heating and firing the green microspheres to form solid refractory microspheres of polycrystalline titanium dioxide, which are useful, for example, in reflective signs or traffic marking surfaces. Said fired fibers and microspheres are preferably transparent to visible light with the titanium dioxide content thereof in its anatase form.

Shaped and fired articles of TiO.sub.2

A thin layer chromatographic plate housing a substrate and bonded there to a layer of discrete, spherical inorganic metal oxide particles bonded to the substrate by an inorganic metal oxide binder the particles and binder being SrO.sub.2, TiO.sub.2, ZrO.sub.2, or Al.sub.2 O.sub.3.

Thin layer chromatographic plates

Thin nonorganic films of complexes of titanium and stannous tin are formed on organic polymeric substrates to provide ultraviolet absorbing coatings which retard degradation of the polymeric material of the substrate due to ultraviolet light.

Growing community of inventors

Maplewood, MN, United States of America

Roger W Lange