GB2337759A - Paint stripping poultice system - Google Patents

Abstract

A paint stripping system is provided which includes a blanket that is adapted to be placed over a chemical paint-stripping composition in order to enhance the efficiency of said composition. The blanket includes a first layer consisting of a machine-glazed tissue paper or natural craft paper, the weight of which is at least 12 g/m<SP>2</SP>. It further includes a second layer of a low-density polyethylene that is laminated to the first layer. The density of low-density polytheylene is at least 918 kg/mm<SP>3</SP>. A preferred low-density polyethylene is polyvinylidene. A method for chemically stripping layers of paint or varnish from a surface is further provided.

Description

1 PAINT STRIPPING POULTICE SYSTEM 2337759 The present invention relates

generally to a paint stripping poultice system and, more particularly, to such a system that includes a universal cover or blanket having at least one non-porous layer laminated to a porous layer. The impermeable layer is preferably composed of a material selected from polyethylene and an ethylene methacrylic acid copolymer material. The porous layer is preferably a glazed tissue paper material. It has been found that the use of such a laminated cover improves the efficiency of virtually all chemical paint-stripping compositions since it creates a poultice-like environment that permits the chemical paint stripping composition to interact more efficiently with the paint or varnish being stripped by preventing evaporation thereof. In addition, it has been found that such a blanket provides a matrix for the softened paintor varnish to adhere, thus facilitating its removal from the surface.

The use of a cover or poultice to be applied over a chemical paintstripping composition to improve its efficiency is well known. See, for example, U.S. Patent NO. 5,188,675 which issued on February 23, 1993 to Michael I.D. Brailsford for Paint System for Removing Paint; U.S. Patent No. 4,579,670 which issued on April 1, 1986 to Michael I.D. Brailsford for Paste Stripper System for Surfaces; and U.S. Patent No. 4,426,250 which issued on January 17, 1984 to Michael I.D. Brailsford for Stripper System for Surfaces.

1 1 1 These patents disclose the use of covers or blankets fabricated from generic materials such as cloth, newspaper or plastics which are intended to limit the evaporation of the chemical paint-stripping compositions over which they are applied. Such blankets permit the chemical paintstripping compositions to penetrate deeply through multiple layers of the paint or varnish in a much shorter time period than if left uncovered. This increases the efficiency of the chemical paint-stripping composition and frequently eliminates the need for repeated applications. It further serves to reduce the amount of labour required and the attendant pollution caused thereby.

A problem heretofore experienced with conventional covers or blankets relates to their unknown permeability. Frequently, this makes them subject to degradation by the chemical paint-stripping composition over which they are applied. Blankets that are particularly permeable tend to absorb the chemical paint-stripping composition and paint or varnish being removed and, therefore, become quite heavy. This impedes their ability to quickly and efficiently remove the paint or varnish coatings from the surface. This problem becomes particularly acute when used on vertical surfaces.

Covers manufactured from plastic sheeting work well in enhancing the efficacy of the chemical paint-stripping compositions. Unfortunately, however, plastic sheeting does not facilitate the removal of the stripped coating because 3 - S the coatings tend not to adhere to the plastic sheeting. As uch, the stripped coating tends to quickly fall away from such covers. This is a particular problem when the system is used outdoors since the removed paint or varnish has actually blown away from the cover.

The present invention consists in a paint stripping blanket adapted to be placed over a chemical paint-stripping composition, said blanket including an inner layer comprising a porous material laminated to an outer layer comprising an impermeable material.

The blanket can be used as part of a poultice system for stripping paint and varnish from coated surfaces. The cover or blanket is adapted to create a poultice-like environment for the chemical paint-stripping composition so as to improve the efficiency of such composition by preventing the evaporation thereof during use.

The outer layer preferably comprises an impermeable material selected from polyethylene and ethylene methacrylic acid copolymer.

The inner layer may for example comprise a layer of a glazed, tissue paper material that is applied directly against the chemical paint- stripping composition.

The blanket further serves to assist the user of the system in physically removing the coating from the surface being stripped.

The system of the invention may be used in conjunction with most chemical paint-stripping compositions such as, for 4 - example, sodium hydroxide, aromatic hydrocarbons, methylene chloride, aliphatic dibasic esters, n-methyl-2-pyrrolidone, furfuryl alcohol and formic acid.

The blanket of the paint stripping system of the present invention requires a pH tolerance of between 1 and 14. It includes at least one porous layer and at least one impermeable layer laminated together. The porous layer is adapted to be applied directly over the chemical paintstripping composition and is formed from a porous material such as, for example, paper. Particularly preferred materials are natural craft paper and machine-glazed tissue paper, preferably having at least 15% recycled postindustrial secondary fibers. In a particularly preferred embodiment, the porous paper layer includes about 20% post industrial secondarv fibers. The weight of the paper layer should be between about 12 g/M2 and about 35 g/m' and, preferably between about 15 g/M2 and about 25 g/M2. A particularly preferred weight for the porous paper layer is between about 18 g/M2 and about 22 g/M2. A particularly preferred brand of such glazed tissue paper is supplied by Saugerties Corp in Saugerties, N.Y.

The blanket of the paint stripping system of the present invention includes an outer, impermeable layer that is laminated or otherwise bonded to the inner, porous layer. This outer, impermeable layer consists of an impermeable material selected from low density polyethylene, highdensity polyethylene, and an ethylene methacrylic acid - copolymer. A preferred material for the impermeable layer is a low- density polyethylene material such as a polyvinylidene. The density of the impermeable material should be between about 918 kg /M3 and about 962 kg /M3 and, preferably, between about 918 kg/m3 and about 930 kg /M3.

In a preferred embodiment, the porous, inner layer is a glazed material on which is laminated the outer, impermeable layer. The combined weight of the laminated blanket should be between about 16 and about 65 g/M2 with a preferred weight between 23 and 45 g/M2. A particularly preferred weight for the blanket is between about 30 and about 40 2 9/m.

The resultant blanket provides a relatively lightweight, laminated cover that affords maximum impermeability to virtually all chemical paintstripping compositions thus preventing impeding degradation thereof. The inner porous layer is absorbent and will readily adhere to the softened or emulsified paint or varnish to facilitate removal thereof, particularly when used in conjunction with a spatula or stripping tool.

The impermeable outer layer creates a vapour barrier for the chemical paint-stripping composition thus impeding evaporation thereof. It further serves to prevent the spread of toxic fumes that may be given off by the chemical paint-stripping composition, thus protecting the public from inadvertent contact not only with the chemical paint- - 6 stripping compositions but also with the underlying paint and varnish coatings. this is particularly important when used to strip lead painE from a surface.

The blanket also serves to protect the chemical paintstripper composition from the elements, which is particularly important when used to remove paint or varnish from exterior surfaces. It also facilitates the removal of coatings from vertical or horizontal situations such as floors or ceilings.

One additional adv-antage of the blanket of the present system is that it can be printed with warnings concerning the potentially hazardous nature of the process and instructions on the stripping process.

It has been discovered that the invention has been particularly effective -.,Then applied over chemical paint stripping compositions -In paste form designed to be used over moulded or other irregular surfaces. In such applications, it creates a reverse mould formed of the paste and softened coating tha-- serves to reduce the need for having to use sharp stripping tools on such delicate surfaces.

The paint strippinj system of the present invention is particularly effective -.,.hen used to remove paints that have been applied using a brush, roller or sprayer. In order to provide an even thickness, it is important the chemical paint stripping composi---Jon be also applied evenly, otherwise an uneven striD will result. By using the blanket - 7 of the system of the present invention, any irregular application of the stripping compound can be smoothed out by hand or a roller. This provides a more even distribution of the paint-stripping composition and, consequentially, a more even or regular stripping of the coating.

The invention as described above can be supplied as sheets or rolls of any size convenient to the area of the application of the chemical paintstripping composition. Similarly, the chemical paint-stripping composition can be provided in liquid, paste or compound form and may be applied by brush, roller, or sprayer or any other method suggested by the manufacturer of the chemical paintstripping composition.

In another embodiment of the present invention, the blanket can be manufactured so that the impermeable layer can be peeled from the paper layer in situ. In such a configuration, the drying process can be accelerated when the paint has been released from the surface and the stripping is complete. This is particularly important when used in combination with sodium hydroxide-based paint stripping compositions since it permits a shrinking and setting process to take place. This allows the remaining paper layer with the attached chemical paint stripping composition and the paint or varnish to be easily pulled away from the surface. When used in conjunction with a delicate plaster moulding, for example, it eliminates the need for sharp tools or excessive water and scrubbing - 8 brushes.

The following examples served to illustrate the use and advantages of the system of the present invention. EXAMPLE 1 A 1900 C paneled Dine door had approximately 30 coats of old oil-based lead and latex paints. It was cut into four sections with eac'- section numbered from 1 to 4. An alkaline paint stripper in paste form was applied to each section to a thickness of approximately 3.2 mm (1kinch). the test was performed indoors at a temperature of 1CC (650F) and at a humid-izy level of approximately 20%. The sections were placed in a vertical position. Section 1 was covered with a blanket having a low- density polyethylene layer laminated to a layer of glazed tissue paper. The weight of the glazed t--'ssue paper was 26 g/M2. Section 2 was covered with two sheets of newspaper; section 3 was covered with a single 7ayer of 4 ml polyethylene; and section 4 was left uncovered. All sections were left for 24 hours and the removal -.,Tas accomplished with a paintstripping tool. Results:

Section 4. Approximately 50% of the paint was removed and the chemical paint-stripping composition was partially dried. In some areas the paint was very difficult to remove as the paste had adhered to the remaining paint. another coating of the paste paint- stripping composition at the same thickness was needed to remove the remaining paint.

9 - Section 3. Approximately 65% of the paint had been removed but with very patchy results due to large air bubbles that had formed under the polyethylene. another coating was required to remove the remaining paint.

Section 2. Approximately 40% of the paint had been removed and the paper had turned dark brown due to the alkalinity. It had partially disintegrated which made it difficult to remove the paper. The paste had not dried out as much as was the case with the uncovered section. Another coat of the stripper was required to remove the remainder of the paint.

Section 1. Apart from some small areas within the crevices in the panelling, all the paint was removed. No further application was required. EXAMPLE 2 The opposite sides of the door sections of Example 1 were coated with the same stripper and to the same thickness. The sections were left outdoors for approximately 24 hours at temperatures ranging from 7 to 200C (45 to 68OF). The door panels were in direct sun for about six hours with medium to light winds. Results:

Section 4. After eight hours in the sun and wind, the alkaline chemical paint-stripping compound had lost most of its moisture and had dried out. The stripper was difficult to remove. when it was finally removed, about 60% of the paint remained.

- Section 3. Although the polyethylene coating stuck to the surface of the chemical paint-stripping compound when first applied, the paintstripping compound formed a crust and began to dry out. During the test, the polyethylene sheet was actually blown off the sample and it was necessary to tape the polyethylene to the surface. At the conclusion of the test, approximately 60% of the paint remained.

Section 2. The results were similar to the sample of Section 3, but it occurred in less time. Approximately 40% of the total paint on the surface was removed after the first application.

Section 1. Due to the action of the wind and sun, a crust formed a seal around the edge of the blanket that held it firmly in place. The action of -the sun through the polyethylene/paper laminated blanket served to increase the temperature within the chemical paint- stripping composition, thereby increasing its efficiency. When tested after 10 hours, it was estimated that the point would have been ready for complete removal. After the 24-hour test period, paint was completely removed leaving bare wood. EXAMPLE 3 Three 929 cm2 (one square foot) sections of an approximately 10 year old metal automobile hood were coated with a methylene chloride paint- stripping composition that had been applied by brush. The test occurred outdoors at a temperature of about 18'C (65'F). One section was covered with the laminated polyethylene/paper blanket of the present invention, the second with a plastic film comprising a layer of Saran Wrap(D and the third section was left uncovered. After 20 minutes the following results were noted. The section covered by the laminated blanket of the present invention was stripped by removing the blanket with a plastic spatula which was inserted between the metal surface and softened paint and paint stripping composition, all of which came away attached to the blanket revealing the original zinc coating. With respect to the second section, the Saran Wrap was removed leaving the stripper and softened paint attached to the surface. The use of a metal scraper was required to remove the composition and some of the paint. Some of the original paint remained, requiring a second application of the chemical paint-stripping composition. The third section, which was left uncovered, required a substantial amount of scraping to remove the paint and two further applications of chemical paintstripping compositions to remove all the paint. In addition, the scraping required to remove the chemical paint-stripping composition and paint in sections two and three penetrated the electroplated zinc, necessitating filling and sanding prior to repainting. EXAMPLE 4 Three sections each measuring 2.5 M2 (three square yards) of a 70 year old brick wall coated with a mixture of whitewash, old lead paint and latex paint were tested in an exterior situation with an ambient temperature of between 12 - 4.5 and 13'C (40 to 55'F). An alkaline paste paint stripping composition was applied to each section to a thickness of about 3.2 mm (I/Binch) and left for eight hours. The first section was covered with the blanket of the present invention; the second section with 4 ml polyethylene and the third section was left uncovered. After eight hours each section was examined with the following results.

The section covered with the blanket of the present invention required additional time to remove all of the paint but the strippe-r was still active and the blanket was put back in place. After a further eight hours all the paint was removed down to the original brick face. The section under the 4 ml polyethylene had fallen off, and the paste was drying out resulting in only about 40% of the,oaint being able to be removed. The uncovered section had dried out completely and had become attached to the partly emulsified paint making it very difficult to remove. EXAMPLE 5 A 30-foot sea cruiser was chosen for this example. object was to remove the anti-fouling coatings from the fiberglass hull using a chemical stripper containing nmethyl-2pyrrolidone as the main active ingredient. The paint stripping composition was applied with a brush to one complete side of the hull to a thickness of about 1.6 mm (l/16 inch). The blanket of the present invention was applied over one half of the area to be stripped and the other half was left uncovered. After six hours, the paint - 13 stripping composition was removed from the entire surface area with the following results: The paint stripping composition on the uncovered side had not dried out although it had lost much of its paint stripping ability. In contrast, the composition over which the blanket of the present invention had been applied stripped the paint down to the fiberglass surface. Furthermore, most of the paint stripping composition and loose anti-fouling paint adhered to the blanket of the present invention and was easily stripped off when the blanket was removed. EXAMPLE 6 An alkaline paint stripping composition was applied to a 1920 C panelled door covered with approximately 20 coats of paint and placed in a vertical position. The composition was applied directly to the outercoated surface and the laminated cover of the present invention comprising a layer of glazed paper and low-density polyethylene was applied over the paint stripping composition. Once the stripping composition had softened and emulsified the first few layers of paint began to slip and fall to the floor taking the paste with it. A comparable area on the same door had the same stripping composition placed over the paint with the blanket of the present invention. The stripping composition and the blanket remained in place until all of the paint was removed.

Claims (14)

1. A paint stripping blanket adapted to be placed over a chemical paintstrlipping composition, said blanket including an inner layer comprising a porous material laminated to an outer layer comprising an impermeable material.

2. A paint stripping blanket according to claim 1 wherein said inner porous layer comprises a layer of a machine glazed tissue paper.

3. A paint stripping blanket according to claim 1 wherein said inner porous layer comprises a layer of natural craft paper.

4. A paint stripping blanket according to any preceding claim wherein the weight of said porous material is between 12 g/m2 and 35 g/M2.

5. A paint stripping blanket according to claim 4 wherein the weight of said porous material is between 15 g/M2 and 25 g/M2.

6. A paint stripping blanket according to claim 5 wherein the weight of said porous material is between 18 g/M2 and 22 g/M2.

7. A paint stripping blanket according to any preceding claim wherein said outer impermeable layer comprises a layer of an impermeable material selected from high-density polyethylene, low-density polyethylene and an ethylene metacrylic acid copolymer.

8. A paint stripping blanket according to claim 7 wherein the impermeable material is a low-density polyethylene.

9. A paint stripping blanket according to any preceding claim wherein the density of the impermeable material is between 918 kg /M3 and 962 kg /MM3.

10. A paint stripping blanket according to claim 9 wherein the density of the impermeable material is between 918 kg /MM3 and 930 kg/mm 3.

11. A paint stripping blanket substantially as herein described with reference to any one of the examples.

12. A paint stripping system including a blanket according to any preceding claim.

13. A method for chemically stripping a coating from a surface, sad method comprising the steps of:

applying a chemical paint stripping composition to said coating over said surface; applying over said composition a blanket according to any one of claims 1 to 10; permitting said composition to interact with the coating to be stripped; and stripping said coating from said surface by physically removing said blanket to which the coating is adhered.

14. A method for chemically stripping a coating from a surface substantially as herein described with reference to any one of the examples.