Easily removable coating protective against solar radiation

Abstract: With the help of a first material (product I) transparent surfaces such as glass plates or outer surfaces of horticultural greenhouses can be provided with a coating protective against solar radiation by spraying or another method, in which this product I becomes indelible as a result of chemical transformation, so that a weather-proof coating is obtained. In order to remove this coating again, one applies a second material (product II) on top of this first material (product I) by spraying, which decomposes the indelibility of the first material, after which both materials can easily be removed from the transparent surface with the help of water.

Description: The invention relates to a method according to the preamble of the main claim. Such a method is known from EP-A-0 115 694 and is used for the temporary protection for painted or polished metal manufactured articles against weathering, contamination from the atmosphere, chemical attack etc. According to the present invention said coating in particular is applied onto a transparent surface such as a glass plate or the outer surface of a (horticultural) greenhouse, said coating material and said second material for removing said coating material being further described in the characterizing portion of said main claim. By applying a coating material onto the outer surface of a greenhouse burning of the plants in the greenhouse in spring and summer is prevented. Obviously the coating material has to be reasonably weather-proof but must be easely removable so that the luminous intensity of the glass wall of the greenhouse is not reduced during a number of months. According to the invention, one effectively makes use of a coating material (product I), which, during utilization thereof as a coating possesses the indelibility (weather-resistancy) required for such a coating, but the indelibility of which, if the material is to be removed again, can be discontinued with the help of the second material (product II), which causes the coating material (product I) to be easily removable, and can be taken off the transparent surface with the help of water (rain or rinse water). Effectively, product I can with that consist of one or more inorganic substances, which in dried condition of product I are light-reflective, one or more film shapers, one or more active substances, a preserving agent and other additives. In particular, product I can contain one or more inorganic pigments, at least one binding agent, at least one surface-active substance, a preserving agent and other additives. An effective binding agent for product I is constituted by a an organic (co)polymere with (neutralized) carboxylic acid residues. A thus composed product I can be brought in sprayable form with the help of water of another suitable solvent, and be applied onto the glass surface to be protected by spraying. Product II, which is used for making the coating consisting of product I removable again, consists of a solvent with at least one basic substance, at least one complex former, at least one surface-active substance and other additives. Particularly, in product II the solvent is water with a number of active components, among which one or more basic substances such as sodium hydroxide, one or more complex shapers such as trisodium salt of nitrilo-triacetic acid, one ore more surface-active substances, and other additives. The coating consisting of product I can be sprayed with such a basic product II, and by action of the basic material product I is decomposed in such a way, that the indelibility thereof disappears, so that product I together with product II are easily removable, for example by spraying clean with water. If one applies a coating, which in humid condition (with rain) need not be transparent, effectively finely divided calcium carbonate can be used as as a suitable pigment in product I. If on the other hand, one desires a coating which also transmits light to a great extent in a humid condition, one could employ for example calcium silicate. A suitable binding agent for product I is further the ammonium salt of hydrolized, partially esterified styrene maleic acid anhydride. In addition, other copolymeres with free carboxylic acid residues are also suitable as binding agent. Such binding agents are only slightly corrosive and are easily removable without burdening the environment. A great advantage of the method according to the invention and the materials used with it, product I and product II, is, that both product I and product II can be applied by spraying, whereby application and removal later on of a coating protective against solar radiation on a glass plate or such like can take place particularly easy. The invention is furhter explained with the help of an embodiment. EXAMPLE A coating material of the following composition was prepared: Composition product I finely divided calcium carbonate 30-60 percent by weight ammonium salt of hydrolized partially esterified copolymere of styrene and maleic acid-anhydride 4-12 percent by weight anti-foam agent 0-0,2 percent by weight thickening agent 0-1 percent by weight preserving agent 0,1 percent by weight non-ionic detergent 0-0,1 percent by weight water up to 100 percent by weight. If this product was sprayed onto glass plates, after drying a coating protective against solar radiation formed, that had indelible properties. For removing this coating again, a second material was prepared with the following composition: Composition product II (in utility concentration) sodium hydroxide 0,05-3 percent by weight trisodium salt of nitrilo-triacetic acid 1-5 percent by weight detergent 0,05-1 percent by weight water up to 100 percent by weight. By spraying with this product II the coating of product I easily came loose, and the glass plates could easily be cleaned by subsequently spraying them with water.

Claims: Method for applying a protective coating material onto a surface, and for removing this coating material afterwards, said coating material being formed by an aqueous composition and can be removed by using a second material in the form of an aqueous solution, characterized in that said coating in particular is applied onto a transparent surface such as a glass plate or the outer surface of a (horticultural) greenhouse, said coating material being formed by an aqueous composition of a finely divided inorganic pigment e.g. calcium carbonate or calcium cilicate, an ammonium salt of an organic copolymer e.g. a hydrolized copolymer of styrene and maleic acid anhydride and additives, which coating material becomes indelible after application as a result of chemical transformation, said second material for removing said coating material being formed by an aqueous solution of one or more basic substances such as sodium hydroxide, one of more chelating agents such as trisodium salt of nitrilo-triacetic acid and additives, which material is brought on top of said coating material such that the indelibility of said coating material is decomposed, after which both materials are removed from the transparent surface with the help of water. Coating material to be used with the method according to claim 1, characterized in that said coating material has the following composition: finely divided calcium carbonate 0-60 % by weight ammonium salt of hydrolized partially esterified copolymere of styrene and maleic acid-anhydride 4-12 % by weight anti-foam agent 0-0.2 % by weight thickening agent 0-1 % by weight perserving agent 0.1 % by weight non-ionic detergent 0-0.1 % by weight water up to 100 % Material for removing a coating material to be used with the method according to claim 1 or 2, characterized in that said second material has the following composition: sodium hydroxide 0.05-3 % by wheight trisodium salt of nitrilo-triacetic acid 1-5 % by weight detergent 0.05-1 % by weight water up to 100 %

Inventors: BERTELS ANTONIUS FRANCISCUS MA, VAN ROSSUM ANTOON JOHANNES GER, BERTELS, ANTONIUS FRANCISCUS MARIA, VAN ROSSUM, ANTOON JOHANNES GERARDUS
Applicants: BERTELS ANTONIUS FRANCISCUS MA, ROSSUM ANTOON JOHANNES GERARDU, BERTELS, ANTONIUS FRANCISCUS MARIA, VAN ROSSUM, ANTOON JOHANNES GERARDUS
Application year: 1991
Main classification: C09D5
IPC codes: C09D5, A01G9