Patent Application
20150034006
The present invention relates to a masking strip, in particular a masking strip for masking the interior surfaces of a gap between two substrates to be painted.
In the automotive repair market it is common to use some type of masking material to achieve an accurate and smooth paint edge when spraying a vehicle part with paint, such as a coloured paint or clear lacquer. Existing products include masking tapes (such as Scotch High Performance Masking Tape 3434, available from 3M United Kingdom plc) and masking foam tapes (such as Soft Edge Masking Foam Tape, again available from 3M United Kingdom plc). One particular use is to mask the interior surfaces of a gap between two vehicle parts, one of which is static and one of which is moveable, such as an “A”, “B” or “C” pillar (the pillar of a vehicle between the windscreen and a front door, between a front door and a rear door, and between a rear door and a backlight, respectively), a front wing and a bonnet and a vehicle door. The aperture created in the vehicle bodywork may be termed the door opening aperture, and is bounded by at least one of the static vehicle parts mentioned above, the roof and the door sill. To achieve a smooth paint line in this situation the masking tape or foam is positioned within the gap between the two parts, and fixed to one of the interior surfaces of the gap between the parts using an adhesive. An edge of the tape or foam is positioned at the top of the gap nearest the surface to be sprayed. This can require considerable skill to achieve a smooth paint line. To improve the repeatability of the paint line several options are available. Firstly, it is possible to fold over one edge of a masking tape onto the adhesive side to create a spacer that acts to lift the edge of the tape away from the interior surface of the gap at the top. Allowing a non-contact region at the top of the gap allows a smooth paint line to be created as there is no pooling of the paint or lacquer against the hard edge of the masking tape. This creates a smooth paint line on the static vehicle part to which the masking tape is affixed with adhesive. Secondly, it is possible to use a masking tape or foam that is provided with a gap filler. An example of this is discussed in WO2008/023081, which is concerned with a sealing strip comprising a lateral adhesive sheet, or backing, which is provided with a joint, or gap, filler formed from an elastomer. The joint filler is positioned within the gap between the two vehicle parts to fill the gap and to be in contact with the interior surface of the gap formed by the moveable vehicle part. In addition, to provide a smooth paint line the lateral adhesive sheet is positioned proud of the top of the gap to prevent overspray.
Even if a spacer or gap filler is provided it may still be necessary to apply the masking strip with skill if masking a complex shape or small gap, both of which are found increasingly in modern vehicles. With this in mind, the foam materials used in masking foam tapes and masking strips may be open cell materials, allowing paint or lacquer that is oversprayed to be absorbed away from the edge of the masking tape or strip. An example of this is discussed in WO2006/109093, which is concerned with a masking strip having at least one non-adhesive foam region that when paint pools against it absorbs the paint and produces a smooth paint line. A second approach is to provide a masking tape material with an absorbent edge coating, such as discussed in WO2003/092996. The absorbent edge material is intended to absorb paint to prevent it from being absorbed by the main body of a masking tape and passing between the tape and the surface it is fixed to, which may otherwise cause a rough paint line. A superabsorbent material is proposed as being particularly suitable to form the absorbent edge material.
However, whilst each of these solutions, when used carefully and correctly, gives a smooth paint line on the movable and/or static vehicle parts, it would be advantageous to be able to produce such a smooth paint line on the static vehicle part repeatedly without the need to employ absorbent foam materials, edge coatings or spacers.
The present invention aims to offer this alternative by providing a masking strip for masking the interior surfaces of a gap between two substrates to be painted, comprising: a backing having a first surface and a second surface, and a gap filler, extending from the backing and adapted to prevent the flow of paint into the gap; wherein the backing is formed from, or attached to, a fibre-containing material that acts to wick paint away from the interior surface of the gap to which the masking strip is fixed.
The advantage of providing a material that wicks paint away from the interior surface of the gap is that any excess paint will not have chance to pool against the edge of the masking strip, which may create a hard edge or otherwise spoil the finish of a smooth paint line.
Preferably the gap filler extends from the first surface or the second surface of the backing
The second surface of the backing may carry an adhesive to fix the masking strip to an interior surface of the gap.
The masking strip may further comprise a spacer attached to the second surface of the backing In this case preferably the spacer is formed from the fibre-containing material The spacer may be a composite spacer comprising a base layer and a cover layer. Preferably the cover layer is a fibre-containing material.
Preferably the fibre-containing material contains at least one of natural, cellulose or synthetic fibres. The fibre-containing material may comprise one of: paper, tissue, woven material or non-woven material. A paper material preferably has a weight in the range 35 to 100 gsm. A paper material may be textured. A tissue material may have a weight in the range 10 to 35 gsm.
The fibre-containing material may be perforated.
Preferably the gap filler comprises a foam material.
The present invention will now be described by way of example only and with reference to the accompanying drawings, in which:
In the present invention a different approach has been adopted. Rather than use an absorbent foam material or a spacer alone to create a smooth paint line on a static vehicle part, a fibre-containing material is employed to wick paint away from the interior surface of the gap to which the masking strip is fixed. By wicking paint away from the interior surface pooling of paint along the edge of the masking strip is avoided, which in turn leads to a smooth paint edge. To ensure that a smooth paint edge is also achieved on the interior surface of the gap to which the masking strip is not fixed, a gap filler is employed. In the following description references to “paint” should be understood to include a base coat (the coloured paint layer seen on vehicles) and a clear coat (also known as lacquer), and a smooth paint edge is an edge that is smooth to touch, which does not cause a finger nail to catch against the edge of the paint coating.
All the embodiments of the present invention described above were made on a laboratory scale and tested in a front door opening aperture of a 2007 Vauxhall Astra 3-door hatchback. In use, the door was opened and the masking strips applied to the interior surface of the static vehicle part, which in this example included the “B” pillar, roof and door sill. The spacer was positioned at the top of the gap adjacent the static vehicle panel and the door closed, causing the gap filler to fill the gap. A clear coat (P190-6990 with hardener P210-872 and diluent P850-1694, all available from PPG Industries (UK) Limited, Needham Road Stowmarket Suffolk IP14 2AD) was sprayed onto the vehicle. All four embodiments of the present invention resulted in a smooth paint line on the static vehicle part tested.
In two of the embodiments described above the fibre-containing material used is a paper material. In the case of crepe paper, the paper material is textured. Suitable paper materials include plain or coloured office paper, crepe paper, tissue paper and lightweight cardstock. Alternatively, the paper material can be chosen by weight, and preferably has a weight in the range of 35 to 100 gsm. Lighterweight tissue materials are employed in the fourth embodiment described above. Such materials can be chosen to have a weight preferably in the range 10 to 35 gsm. As an alternative to the non-woven material used in the third embodiment described above, woven materials, such as textiles, may be used as the fibre-containing materials. In each case, suitable materials are those that do no exhibit excessive linting or other disintegration or delamination behaviour in use or manufacture of the masking strip.
Preferably the fibre-containing material contains at least one of natural, cellulose or synthetic fibres. Suitable natural fibres include vegetable and animal derived fibres such as: silk, cotton, jute, flax, ramie, sisal, and hemp; suitable cellulose fibres include regenerated and pure cellulose, such as rayon; suitable synthetic fibres include extruded fibres such as: nylon, polyester, acrylic, polypropylene and polyolefin. To improve the wicking behaviour of the fibre-containing material it may be perforated. The spacer 23, 31, 39 has a thickness preferably in the range 0.6 mm and 1.1 mm. The height of the spacer 23, 31, 39 is preferably in the 3 mm and 8 mm.
The gap filler 13, 20, 28, 36 is preferably formed from a foam material, such as an open or closed cell foam material, but is preferably a closed-cell foam material such as a polyurethane foam, for example, Caligen X4200AM (RTM), available in the UK from CALIGEN FOAM LTD, Broad Oak, Accrington, Lancashire, BB5 2BS. The gap filler 13, 20, 28, 36 may be crimped at the point it extends from the backing 10, 17, 25, 33. If the backing 17, 25, 33 is not formed from the fibre-containing material it is also preferably formed from a foam material, such as an open or a closed cell material. The gap filler 13, 20, 28, 36 extends from the backing 10, 17, 25, 33 so as to be parallel in
In the embodiments of the present invention where the backing is a foam material, it is preferably a strip of flexible, compressible and/or conformable material, such as a polyethylene foam material, for example, Aveolite TA1001®, available in the UK from SEKISUI ALVEO AG, Queens Chambers, Eleanors Cross, Dunstable, Bedfordshire, LU6 1SU. Where the gap filler 13, 20, 28, 36 and the backing 10, 17, 25, 33 are both foam materials, one may be chosen to be more dense than the other, for example, the foam material forming the backing 10, 17, 25, 33 may be more dense than the foam material forming the gap filler 13, 20, 28, 36.
In the above embodiments of the present invention a two-part construction of the masking strip (utilising a separate gap filler 13, 20, 28, 36 and backing 10, 17, 25, 33) is used. In this case the gap filler may extends from either the first or the second surface of the backing, with the former being shown in the embodiments. However, the backing 10, 17, 25, 33 and the gap filler 13, 20, 28, 36 may be formed as an integral body from a single strip of material, such as a foam material or a fibre-containing material (in the case of the first embodiment of the present invention).
The embodiments of the present invention described above are suitable for use in masking a gap formed between any static and moveable vehicle panel forming part of a door opening aperture. A door may be framed or frameless, and the gap filler 13, 20, 28, 36 may be sized to fill a large gap or a small gap, or may be folded in on itself or shaped to create a compressible body that is easily positioned and held within either a large gap or a small gap.
Although the backing 17, 25, 33 and gap filler 13, 20, 28, 36 when formed of a foam material are preferably elongate bodies of rectangular cross-section, the cross-section of each may be triangular, elliptical or polygonal. In each of the embodiments described above, the gap filler 13, 20, 28, 36 extends from the first surface 11, 18, 26, 34 of the backing 10, 17, 25, 33. However, as an alternative the gap filler 13, 20, 28, 36 may extend from the second surface 12, 19, 27, 35 of the backing 10, 17, 25, 33. In this case it may also be folded or otherwise bent away from the adhesive layer 15, 22, 30a, 38b. Any suitable adhesive may be used to join the backing 10, 17, 25, 33, the gap filler 13, 20, 28, 36, the spacer 23, 31, 39, and the parts of the composite spacer 31, 31a, 31b, 39, 39a, 39b together.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1021983.0 | Dec 2010 | GB | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US11/66364 | 12/21/2011 | WO | 00 | 1/16/2014 |
