MATERIALS CONTAINING FLUORESCING ADDITIVE

Abstract: The invention relates to rubbers, polymers, resins and similar materials which contain as a fluorescent additive a fraction distilled from crude oil, the fraction containing in the main aromatic and naphthenic compounds and being visible, i.e. fluorescent, in ultraviolet light. The additive is needed in only small amounts, usually less than 1 % of the total amount of the material. The materials mixed with the additive can be used for manufacturing various safety equipment and for marking various types of equipment, structures or packaging which should be distinguishable especially in conditions of poor visibility.

Description: Materials containing fluorescing additive. The invention relates to rubbers, polymers or resins which have been rendered fluorescent by adding an additive fluorescent in UV light. In a case in which it is desirable to make certain parts or areas of an object clearly distinguishable from the background, the conventional method is to illuminate those objects more or less strongly with visible light. Objects which should be clearly visible may also be painted with a strongly distinguishable color, or such color may be admixed with them. Owing to the prevailing circumstances, conventional visible light may not always penetrate effectively enough through the medium to the object, and therefrom to the observer. Such a situation may prevail in the natural environment in rain or fog, or in a closed space in which the atmosphere is, for example, more or less saturated with liquid or solid particles, whereby the penetration of visible light through the atmosphere is weak¬ ened. A solution to the problem is to use, instead of visible light, radiation of approx. 350 - 400 nm within the ultraviolet wavelength, and to use in the manufacture of the object which should be visible an additive fluorescent in UV light. Thus a certain object can be distinguished very well from its background and/or from other surrounding objects. The use of plastics in both exterior and interior spaces is constantly increasing. Therefore there is a need for plastics and corresponding materials with an improved visibility in UV light. According to the invention it has been observed that various polymeric materials can be rendered fluorescent in UV light by adding to the materials small amounts of certain fractions obtained from crude oil. Thus the rubbers, polymers, resins or similar materials which contain a fluorescent material in accordance with the invention are characterized in that there has been admixed with them, as a fluorescent additive, a fraction obtained at 350-400 °C in the distillation of crude oil, the fraction containing in the main aromatic and naphthenic compounds. If the oil fraction is separated by distillation, the fraction concerned is the fraction distilling at 350-400 °C in vacuum distillation. This is so-called heavy vacuum gas oil, i.e. HVGO. The oil fraction may also be a fraction somewhat heavier than HVGO, i.e. flux oil for blowing, used in the oxidation of bitumen. If the object to be illuminated is made from rubber, polyester, resin, or some other material of corresponding type, it is possible to admix with the material a fraction distilled at a high temperature, e.g. 350 - 400 °C, in the distillation of crude oil, the fraction containing large amounts of aromatic compounds and containing no asphaltenic compounds or a very small amount of them. The rubber, polymer, resin or corresponding material may be any substance of this type with which the said fluorescent crude oil fraction can be admixed. It may be a natural macromolecule or a synthetic polymer, with which a number of other additives may be admixed, depending on the intended use. The material may be entirely of the above- mentioned plastic material, or the suitable base or frame structure may be, for example in order to provide mechanical strength and/or rigidity, of some other material such as wood, metal, various macromolecules, glass or various ceramic materials, and this base or frame may be coated with a fluorescent rubber, resin, polymer or the like. The polymer may be, for example, a polyolefin such as polyethylene, polypropylene, or a mixed polymer of various olefins, or a polymer of styrene, vinyl chloride or various other monomers, which polymers may have rubber-like, i.e. elastomeric properties. Many natural resins and macromolecules, some examples being cellulose derivatives, natural rubber, starch derivatives, etc., are usable. A fluorescent oil-like additive needs to be admixed in only small amounts with the macromolecular substances in order that the entire mixture, and the piece, package, coating, etc., made therefrom, should be fluorescent in UV light. The amount to be admixed is 0.01 - 10 %, preferably less than 1 %. In this case the other properties of the polymers and corresponding materials do not substantially change, and the said pieces which have been manufactured from the material containing the additive may be used for the same purposes as the material not containing the additive. Typical objects fluorescent in UV light are lane markings, roadway markings, traffic signs, guide posts, curbstones, curb markers, and many kinds of safety and security equipment and markings on roadways. Furthermore, fluorescent materials may be used in buoys and life belts to increase safety in navigation. The penetration of UV light in poor visibility conditions, such as fog and rain, is better than that of visible light. Packaging for hazardous substances may be made from fluorescent plastics, in which case, for example, in a fire situation the packages can be rapidly recognized and removed from the scene of the fire. In places in which maintaining night vision is important, such as the cockpits of ships and airplanes, switches and scales made of a fluorescent material may be "illuminated" with UV light without reducing dark adaptation of the eye. The functioning of the invention is described below with examples, which are, however, not intended as limiting the use of fluorescent additives only to the mixtures and objects described in the examples. Example 1. Flux oil having a viscosity of 85 mm 2 /s at 50 °C was admixed at a rate of 0.1 % with EVA polymer B-5028 (a copolymer of ethylene and vinyl alcohol, manufacturer Neste Oy). A sheet was prepared from the mixture, and the sheet was irradiated with a 160 W Claude Mixopal UV lamp. The mixture was fluorescent, but the properties of the mixture did not otherwise change substantially. Example 2. A HVGO-type oil fraction was melt-mixed at a rate of 0.1 % with polyethylene plastic NCPE 2224 (Neste Oy). The material was compression molded into a sheet, which was fluorescent in UV light. The UV lamp used was a 160 W Claude Mixopal lamp having a wavelength range of 350-400 nm. Example 3. A HVGO-type oil fraction was melt-mixed at a rate of 0.1 % with polystyrene plastic SP 453 (Neste Oy). A sheet compression molded from the material fluoresced intensely in the light of a Claude Mixopal lamp. Example 4. A HVGO-type oil fraction was melt-mixed at a rate of 5 % with styrene-butadiene-styrene elastomer Vector 241 ID (manufacturer Dexco Inc). A sheet compression molded from the material fluoresced in the light of a Claude Mixopal lamp. The fluorescence produced in the above examples was white. Plastic materials with which an additive has not been admixed according to the invention are not distinguishable in UV light.

Claims: Claims 1. Rubbers, polymers and resins containing a fluorescent additive, characterized in that with the said materials there has been admixed at a rate of 0.01 - 10 %, preferably 0.1 - 1 %, an additive fluorescent in ultraviolet radiation, the additive containing in the main aromatic and naphthenic compounds, but containing only a small amount of or no asphaltenic compounds. 2. A rubber, polymer or resin material according to Claim 1, characterized in that the fluorescent material is admixed with copolymers of polyethylene or ethylene. 3. A rubber, polymer or resin according to Claim 1 or 2, characterized in that the fluorescent material is admixed with a homo- or copolymer of styrene.

Inventors: BLOMBERG TIMO, TURPEINEN HARRI, BLOMBERG, TIMO, TURPEINEN, HARRI
Applicants: BLOMBERG TIMO, NESTE OY, TURPEINEN HARRI
Application year: 1993
Main classification: C08K5
IPC codes: C08K5, C08L21, C08L23, C08L101