Masking member

Abstract: A masking member (100) for use in a spray coating process comprising a molded foamed polystyrene panel (101) having a closed cell structure, a density in the range 12.5-50 g/l, a layer of emulsion-type adhesive (103) formed on one side of said panel (101), a release sheet (104) covering said adhesive layer (103), said panel (101) having grooves (102) formed on one side of said panel (101) or on both sides of said panel (101) and opposite each other, said grooves (102) having a depth such that the thickness of the polystyrene panel (101) beneath or between said grooves (102) is in the range about 0.30-0.85 times the thickness of the panel (101).

Description: The instant invention relates to a new masking member used to protect a part of the surface of an article from a spray coating, according to the preamble of claim 1. A spray coating is very difficult to coat locally on the surface of an article since such coating material is spread when said coating material is sprayed from a spray gun. Therefore, a masking member is necessary to protect part(s) of the surface of said article to be protected from said coating. Hitherto, adhesive tapes have been used as a masking member to protect a part of the surface of an article from said spray coating. Namely, said adhesive tapes are attached to a part of the surface of an article to protect it from said spray coating, and after said spray coating, said adhesive tapes are removed from the part of the article. Said part is not affected by said spray coating since said part was covered with said adhesive tapes during said spray coating. Nevertheless, said adhesive tapes as the masking member have faults in cases where the part to be protected from said spray coating is wide; it is troublesome to attach said adhesive tapes to the part to be protected and to remove said adhesive tapes from said part since a number of strips of said adhesive tapes must be attached to said part to cover the whole part. Further, in a case where said adhesive tapes are subjected to heat, said adhesive tapes stick to the part due to heating and the stripping of said adhesive tapes becomes very difficult. Said difficulty of attaching and removing of the masking member to/from the part to be protected may be a very serious problem, particularly for a continuous spray coating process in a mass-production system such as the spray coating process for a car body, electric utensils and the like. EP-A-0249444 discloses a corrosion, sound and vibration-proofing method involving applying temporary masking members to a surface which is then coated except in the masked places whereon the members are removed. According to the present invention there is provided a masking member for use in a spray coating process comprising a molded foamed panel with a layer of adhesive on one side and a release sheet covering said adhesive layer, said panel having grooves formed on one side of said panel or on both sides of said panel and opposite each other, characterised in that said panel is of polystyrene and has a closed cell structure and a density in the range 12.5-50 g/l, in that said adhesive is a layer of emulsion-type adhesive, and in that said grooves have a depth such that the thickness of the polystyrene panel beneath or between said grooves is in the range about 0.30-0.85 times the thickness of the panel elsewhere. When said masking member is used, said release sheet is removed from said adhesive layer and said masking member is snapped along selected grooves by hand to form a piece having the proper size corresponding with a part of an article which it is necessary to protect from a surface treatment. An object of a preferred feature of the invention is to prevent the adhesive layer from soaking into the panel since said panel consists of foamed polystyrene and the adhesive layer is formed by coating an emulsion type adhesive having a slow drying speed. This can be attained by a primer layer being an intermediate layer between said panel and the adhesive layer. To assist in easily snapping said masking member along said grooves to a piece having a proper size corresponding with a part of an article which is necessary to be protected from a surface treatment cutting lines may be included in the release sheet. The invention will be better understood from the following description which is given by way of example only with refrence to the accompanying drawings in which: Fig. 1 is a partial perspective view of a first embodiment of the instant invention. Fig. 2 is a partial side sectional view of the first embodiment of the instant invention. Fig. 3 is a partial perspective view of the first embodiment of the instant invention in the case of coating. Fig. 4 is a partial perspective view of the first embodiment of the instant invention in the case of removing the masking member from the article. Fig. 5 is a partial perspective view of a second embodiment of the instant invention. Fig. 6 is partial side sectional view of the second embodiment of the instant invention. Fig. 7 is a partial perspective view of a third embodiment of the instant invention. Fig. 8 is a partial side sectional view of the third embodiment of the instant invention. Fig. 9 is a perspective view of a piece of the third embodiment. Fig. 10 is a plane view of another embodiment of the release sheet having cutting lines. Fig. 11 is a plane view of further embodiment of the release sheet having cutting lines. Fig. 1 to Fig. 4 relate to a first embodiment of the instant invention. Referring now to Fig. 1 to FIg. 4 a masking member (100) comprises a panel (101) consisting of foamed polystyrene made by bead molding and having closed cells. Checkered grooves (102) are formed at regular intervals on both sides of said panel (101), and an adhesive layer (103) is formed on a side of said panel (101) and said grooves (102) are formed directly opposite each other. Said adhesive layer (103) is covered with a release sheet (104) such as a polyethylene film, a polypropylene film, a release paper, and the like to prevent sticking to another article, hands of workers, and the like when the masking member is handled, one placed upon another, transported, and the like. Said grooves may be formed when the panel is molded or by cutting after the panel is molded or cut out. When the masking member (100) is used, the release sheet (104) is removed from the adhesive layer (103) and the panel (101) is snapped along the grooves by hand to a piece having the proper size corresponding with a part (201) of an article (200) which is to be protected from a surface treatment such as coating, plating, phosphatizing and the like. The resulting piece is then attached to said part (201) of the surface of said article (200) by said adhesive layer (103) thereof as shown in Fig. 3. Paint is sprayed from a spray gun (300) on the surface of said article (200). The said part (201) of the surface of said article (200) is not subjected to said paint since said part (200) is covered with said piece of the masking member (100). After painting, said painted article (200) is heated to dry and /or cure if desired. After or before said heating, said piece is stripped by a hook (400), as shown in Fig. 4, or by hand or in a case where the heating temperature is higher enough than the softening point of the plastic used as the material of said panel (101), said piece will shrink by said heating and come off by itself from said part (201) of said article (200). Said formed polystyrene is made by bead molding and has closed cells and further, the density of said foamed polystyrene should be in the range 12.5 to 50 g/l and said grooves have a depth such that the thickness B of the polystyrene panel beneath or between said opposed grooves is in the range about 0.30-0.85 A, wherein A is the thickness of said foamed polystyrene panel. Said foamed polystyrene panel having closed cells may be very easily snapped along the grooves by hand since said foamed polystyrene is very brittle and the cell walls of said closed cells of said foamed polystyrene adhered weakly to each other. Nevertheless if the density of said foamed polystyrene is less than 12.5g/l and the thickness B is less than 0.30 A, the masking member may be easily broken along said grooves during operations such as transportation, storage, and the like and if the density of said foamed polystyrene is more than 50 g/l and the thickness B is more than 0.85 A, it may be difficult to snap said masking member along said grooves. Said adhesive layer (103) should be formed by coating an emulsion-type adhesive since said masking member comprises a foamed polystyrene panel having poor solvent-resistance and said emulsion-type adhesive contains only water as a solvent. Fig. 5 and Fig. 6 relate to the second embodiment of the instant invention. Referring now to Fig. 5 and Fig. 6 a masking member (110) comprises a panel (111) consisting of the same foamed polystyrene, and grooves (112), the same as in the first embodiment are formed on both sides of said panel (111). A primer layer (115) is formed on one side of said panel (111) and an adhesive layer (113) is formed on said primer layer (115). Said adhesive layer (113) is covered with a release sheet (114), the same as in the first embodiment. Said primer layer (115) prevents said adhesive layer (113) soaking into the panel (111) since said panel (111) consists of foamed polystyrene and the surface of said panel (111) is porous and further, as before mentioned, said adhesive layer is formed by the coating of an emulsion-type adhesive which has a slow drying speed and high penetrating property, and said primer layer (115) is formed by laminating a film of plastic such as polyethylene, polypropylene, vinylacetate-ethylene copolymer, polyvinylchloride and the like by heating or adhesive, or by coating with an emulsion or a solution of synthetic resin such as acrylic resin, polyvinylacetate resin, polyethylene, polypropylene, vinyl acetate-ethylene copolymer and the like, on a side of said panel (111). Further, the skin-like layer formed on the surface of said panel (111) since said panel (111) is made by bead molding, may also be used as said primer layer (115). Fig. 7 to Fig. 9 relate to a third embodment of the instant invention. Referring now to Fig. 7 to Fig. 9, a masking member (12) comprises a panel (121) again consisting of the same foamed polystyrene as in the first and second embodiments, and grooves (122), the same as in the first and second embodiments, are formed on both sides of said panel (121). An adhesive layer (123) is formed on a side of said panel (121) and said adhesive layer (123) is covered with a release sheet (124). Cuting lines (124A) along the grooves (122) of said panel (121) are formed in the release sheet (124). When the masking member (120) is used, said panel (121) is snapped along said grooves (122) by hand to a piece (121A) having a size corresponding with a part of the surface of an article and at the same time, said release sheet (124) is easily snapped along the cutting lines (124A). Said cutting lines may include perforated lines (124B) as shown in Fig. 10 and discontinuous lines (124C) as shown in Fig. 11.

Claims: A masking member for use in a spray coating process comprising a molded foamed panel (101, 111, 121) with a layer of adhesive (103, 113, 123) on one side and a release sheet (104, 114, 124) covering said adhesive layer, said panel having grooves (102, 112, 122) formed on one side of said panel or on both sides of said panel and opposite each other, characterised in that said panel is of polystyrene and has a closed cell structure and a density in the range 12.5-50 g/l, in that said adhesive is a layer of emulsion-type adhesive, and in that said grooves have a depth such that the thickness of the polystyrene panel beneath or between said grooves is in the range about 0.30-0.85 times the thickness of the panel elsewhere. A masking member of claim 1, wherein a primer layer (115) is provided between said panel (111) and said adhesive layer (113) to prevent said emulsion-type adhesive from soaking into said panel when said emulsion-type adhesive is coated on one side of said panel to form said adhesive layer. A masking member of claim 1 or 2 wherein said masking member is used to mask a car in the spray coating process of cars. A masking member of claim 3, wherein said masking member is used to mask the underside of a car. A masking member of claim 4, wherein a polyvinyl chloride sol is applied by spray coating to the underside of a car. A masking member of claim 1 or 2 wherein said masking member is used to mask an electric utensil in the spray coating process of electric utensils. A method of coating a utensil or car body by covering selected portions thereof by adhering thereto one or more masking portions taken from a masking member according to claim 1 or 2 by snapping off along said grooves, applying the coating and removing said portions. A method of masking selected portions of a utensil or car body during spray coating thereof using a masking member as claimed in either claim 1 or claim 2, comprising snapping off masking portions of the masking member along said grooves, adhering the masking portions to the selected portions of the utensil or car body and, after application of the spray coating, removing the masking portions. A method according to claim 7 or 8, wherein the portions are removed using a hook.

Inventors: HORIKI SEINOSUKE C O NAGOYA OI, IWATA HISAMI C O TOYOTA JIDOSH, MAKINO REIJI C O NAGOYA OILCHE, HORIKI, SEINOSUKE C/O NAGOYA OILCHEMICAL CO., LTD., IWATA, HISAMI C/O TOYOTA JIDOSHA KABUSHIKIKAISHA, MAKINO, REIJI C/O NAGOYA OILCHEMICAL CO., LTD.
Applicants: NAGOYA OILCHEMICAL, NAGOYA OILCHEMICAL CO., LTD.
Application year: 1989
Main classification: B05B15
IPC codes: C09J7, B05C17, B05B15