Adhesive masking tape

0001The invention relates to a self-adhesive protective film preferably for the protection of Finish of automobiles against undesirable contamination and damage during the assembly and transportation.

0002The preservation and protection of motor vehicles in transit from Manufacturer to dealer has been practiced for some time. It is known that to preserve cars, paraffin waxes in the thickness of 5 to 20 are applied to. It has been found that, especially on horizontal areas of the vehicles, a thin and usually nonuniform coat against external influences such as the corrosive effect of bird droppings, not enough provides protection. A considerable disadvantage of sealing with paraffin wax is the need to remove the preservative using a steam jet, surfactants or solvents. The environmentally friendly Rückgewinnug and disposal of the residues entail considerable deployment of apparatus also very high costs.

0003Self-protective films for motor vehicles have also for some time known. In most cases, these are permanently adhesive Protective Decorative films, such as a stone chip protection film. These remain self-adhesive films following its permanently on the vehicle.

0004Reversibly self-adhesive films for protecting the car during transportation have been found only in a few special cases without much success using.

0005Thus, in 1977 a self-adhesive film from Beiersdorf AG, consisting of a PVC film having a crosslinked self-adhesive composition of polyacrylate and isocyanate, to Protection of the coating on the front of the vehicle against stone chips and dirt used by impacting insects during the running of the automobile. However, the application was found to be problematic because the polyacrylate composition very had to be highly crosslinked to no interaction with the vehicle to paint show. This led to application problems due to insufficient adhesion of Film.

0006Also known are polyacrylate compositions which are not crosslinked and after 16 hours at 80 ° C a good compatibility with paint surfaces show, but they are so soft that they left on the primer when the film is ground residues. Once this Compositions are chemically or radiation-crosslinked, they can be pulled off without leaving a residue, but then give rise to permanent deformations on the paint surface.

0007From Japanese Patent Application JP 02 199 184 discloses a radiation-crosslinkable pressure known, in which for the protective lacquer layers applied to a low glass transition temperature must be set to permanent deformations of the varnish layer to prevent. There are problems owing to inadequate bond strength of the self-adhesive film on motor vehicles to during transport and storage in the open air.

0008European Patent Application EP 0519278 discloses the protection of automobiles a film which consists of a carrier which, with a pressure-sensitive rubber-based adhesive of a dynamic modulus of elasticity of 2 x 10⁵ to 7 x 10⁶ dyne / cm², Corresponding to SI units a value of 2 x 10⁴ to 70 x 10⁴ Pa, at 60 ° C, is coated. Of the Adhesive may also with a silicone oil or a low molecular weight acrylic polymer be mixed. Performance tests with a self-adhesive film indicate relatively good compatibility with paint surfaces. The adhesive strength after However, alternating climatic conditions on customary in the automotive industry paints is low that the required bond in practice not always sufficient given is. Particularly in wet conditions on the film, the adhesive strength is often reduced so that the film during transportation of the vehicle it is protecting becomes detached so that no protection exists. Furthermore is called elastic modulus range not a sufficient criterion for a serviceable Adhesive.

0009The object of the invention is to remedy this situation, in particular a self-adhesive was to provide protective film that does not, or at least the disadvantages of the prior art not to the same extent.

0010This object is achieved by a self-adhesive protective film as in the claims characterized in more detail.

0011The protective film of the invention is a self-adhesive protective film, having as a carrier, a film with a self-adhesive composition of polyethylene - Depending on the type and compounding - with a loss angle tan δ of 0.6 to 1.0, measured at a temperature of 60 ° C and a frequency of 10^-2 Hz, and 0.4 to 0.7, measured at a temperature of 60 ° C and a frequency of 10 Hz, is coated. The protective film has a thickness of 50 to 200 microns, preferably 65 to 80 order.

0012The film preferably consists of polypropylene, polyethylene or a mixture of two components. The film has a thickness of 10 to 100 microns, preferably 50 to 60 in order to. Furthermore, the film in a preferred embodiment is free of halogen. to improve the unrolling properties from a large roll, the film has on its back be provided with a release coating.

0013To optimize the properties of the self-adhesive may with one or more Additives such as rosin esters, hydrocarbon resins, paraffin oils, anti-aging agents mixed or elastomers and yet be free of halogen beyond.

0014To improve the anchoring of the adhesive to the film is the use of a primer possible.

0015For self-adhesive protective films use different adhesive compositions is possible. The Most, however, have serious disadvantages which severely restrict their use.

0016Ultimate Evolution size for a self-adhesive system that the use Such protectors fulfilled any conditions, the rheological profile of the compounded self-adhesive system. Thus, should the glass transition point, characterized by a tan δ maximum, are at temperatures from -5 ° to -25 ° C. and the maximum nearly frequency constant assume values ​​of up to 1.0. This ensures an excellent Repositioning due to a very low initial. At temperatures above from 10 to 30 ° C, preferably 20 ° C, an increase in the tan δ is a function of the Temperature required. It should at 60 ° C the tan δ at 10^-2 Hz minimal 0.6 amounted to at fall 10 Hz to a minimum 0.4. This ensures the marked rise in bond within the first 30 minutes after bonding.

0017Known non-polar self-adhesive compositions, comprising polyacrylate and polyurethane show in the test, in which they are applied for 16 hours at 80 ° C on painted sheets, better Paint compatibility than polar compositions. However, on the other hand they are too soft and residues of composition when the film is removed. If the masses or radiation- are chemically crosslinked, they lead to unwanted paint-film deformation.

0018Self-adhesive compositions based on natural rubber resin can no residue at very Pull lower resist deformation. These compositions are, however, under the influence of UV radiation is not stable to aging.

0019A self-adhesive polyisobutylene with the loss modulus G "of G" = 1.29 x 10⁶dyne / cm², Corresponding in SI units to a value of G "= 12.9 x 10⁴ Pa, and a Loss angle tan δ of 0.2 (both values ​​measured at a temperature of 60 ° C and a frequency of 1 Hz) shows only very slight paint deformations. However, the Peel force is very low from the paint surface by alternating climatic conditions and thus not properly set.

0020For the skilled worker shows a predictable on a polypropylene / polyethylene film smeared self-adhesive composition of polyethylene vinyl acetate with a loss angle tan δ from 0.6 to 1.0, measured at a temperature of 60 ° C and a frequency of 10^-2 Hz, and from 0.4 to 0.7, measured at a temperature of 60 ° C and a frequency of 10 Hz, the desired properties. In particular, on a 50 micron thick polypropylene / polyethylene film, in which the two polymers in a ratio of 9: 9: 1 to 1 preferably 4: 6, used and having a pre-coat of polyethylene vinyl acetate, shows the self-adhesive composition according to the invention on with polyurethane varnish lacki Erten and 130 ° C dried sheets after storage for 16 hours at 80 ° C no deformation lacquer.

0021The peel force of the protective film of the invention of various adhesion reasons is practical 2 to 5 N / cm. Even exposure of the protective film with UV light, For example, with a 500 W strong UV lamp with a sunlight spectrum over 5 days, resulting in no detectable degradation of the properties of the protective film. It occurs no embrittlement, and the self-adhesive composition causes neither paint deformations nor residues of composition occur to peel off the protective film.

0022In addition, the protective film of the invention is characterized in that it in great width over the hood, roof and trunk of the automobile is to apply and to plan because of its flexibility and easy spherically shaped surfaces adapts very well. This is to protect the most vulnerable to pollution horizontal Surfaces possible. However, even narrow areas such as the door leads below the windows can be easily covered. Protection of the vertical surfaces on the vehicle is particularly appropriate during its assembly.

0023The self-adhesive composition has on the one hand on different in the automotive industry stoving enamels common good adhesion to, even under humidity or Humid climate influence, so that the protective film even under wind exposure not from Vehicle replaces, on the other hand it is reversible due to very low initial adhesive adhesive, so that during application to correct the position of the protective film is the vehicle possible. In addition, the self-adhesive composition shows a distinct Rise in bond strength even with low initial adhesive force and within the first 30 minutes after bonding.

0024The protective film is resistant to sunlight, moisture, heat and cold, the Weathering resistance is given up to six months.

0025After application of the protective film and by the self-adhesive composition after storage for 16 hours at 80 ° C and under atmospheric influence any deformations of including lying on coat. Moreover, ensuring the uniform overall thickness the protective film in comparison to preservation with wax, flawless protection against contamination and damage of the entire vehicle.

0026After use, the protective film is without residue despite the good adhesion it necessarily removable and without tearing the backing film. Since the protective film is halogen-free, is a material or energy recovery the same problem.

0027In the following the invention will be explained with reference to examples which are not so however wishing to restrict unnecessary.

Examples

example 1

0028A self-adhesive composition of polyethylene, the toluene in a proportion of 15% is dissolved, tan with a vinyl acetate content of 45 wt .-% and a loss angle δ of 0.8, at a temperature of 60 ° C and a frequency of 10^-2 measured Hz is, is in a coating unit with coating bar and drying tunnel on a 50 .mu.m thick, 1450 mm wide, both sides corona-pretreated, with Carbamatlack and with EVA-Primer provided white foil with 15 g / m² applied, wherein the film of 90% Polypropylene and 10% polyethylene. The drying temperature is 60 to 100 ° C with a residence time of 3 minutes. On channel end is coated circumcised carrier web at the edges and bars of 66 m in length and 1400 mm Width wound.

0029The self-adhesive film produced can be in use for the protection of motor vehicles wrinkle-free handle, applied flawlessly and after use without defects again pull it off.

0030The material is characterized by the following physical properties:<tables><table><tgroup cols="2"><tbody><row><entry align="left">Overall thickness of protective film:</entry><entry align="left">65 microns</entry></row><row><entry align="left">Peel strength from the PU varnish after storage for 16 hours at 80 ° C, a peel angle of less than 90 ° and a peel rate of 300 mm / min:</entry><entry align="left">3.8 N / cm</entry></row><row><entry align="left">Peel force from the reverse side at a peel angle of less than 90 ° and a peel rate of 300 mm / min:</entry><entry align="left">0.5 N / cm</entry></row></tbody></tgroup></table></tables>The measurements were performed with an instrument from Rheometric Scientific under deformation-constant Conditions performed.

example 2

0031Referring to Example 1 is initially 90 wt .-% polyethylene vinyl acetate with a vinyl acetate content of 45 wt .-% and a loss angle tan δ of 0.78 (60 ° C and 10^-2 Hz) and 10 wt .-% rosin ester with a softening point of 85 ° C mixed, dissolved in toluene in a proportion of 15%, and according to Example 1 on a Film consisting of 80% polypropylene and 20% polyethylene, with 12 g / m²coated.

0032The material is characterized by the following physical properties:<tables><table><tgroup cols="2"><tbody><row><entry align="left">Overall thickness of protective film:</entry><entry align="left">63 microns</entry></row><row><entry align="left">Peel strength from the PU varnish after storage for 16 hours at 80 ° C, a peel angle of less than 90 ° and a peel rate of 300 mm / min:</entry><entry align="left">3.1 N / cm</entry></row><row><entry align="left">Peel force from the reverse side at a peel angle of less than 90 ° and a peel rate of 300 mm / min:</entry><entry align="left">0.4 N / cm</entry></row></tbody></tgroup></table></tables>

example 3

0033A self-adhesive composition of polyethylene vinyl acetate with a vinyl acetate of 45 Wt .-% and a loss angle tan δ of 0.6 (60 ° C and 10 Hz) is in an extruder with slot die in coextrusion at 160 to 170 ° C with a layer of Example 1 known film extruded in the width of 1700 mm, the self-adhesive composition having 15 g / m² is applied. The film receives a thickness of 52 microns. Then this cut into rolls of 66 m length and 1500 mm width.

0034The material is characterized by the following physical properties:<tables><table><tgroup cols="2"><tbody><row><entry align="left">Overall thickness of protective film:</entry><entry align="left">67 microns</entry></row><row><entry align="left">Peel strength from the PU varnish after storage for 16 hours at 80 ° C, a peel angle of less than 90 ° and a peel rate of 300 mm / min:</entry><entry align="left">3.2 N / cm</entry></row><row><entry align="left">Peel force from the reverse side at a peel angle of less than 90 ° and a peel rate of 300 mm / min:</entry><entry align="left">0.5 N / cm</entry></row></tbody></tgroup></table></tables>

example 4

0035Referring to Example 3 are initially 90 wt .-% polyethylene vinyl acetate with a vinyl acetate content of 45 wt .-% and a loss angle tan δ of 0.58 (60 ° C and 10 Hz) and 10 wt .-% rosin ester with a softening point of 85 ° C and mixed according to example 3 co-extruded with a film is known from Example 1 wherein the self-adhesive composition having 19 g / m² is applied. This gives the film a Thickness of 61 microns.

The material is characterized by the following physical properties:

0036<tables><table><tgroup cols="2"><tbody><row><entry align="left">Overall thickness of protective film:</entry><entry align="left">80 microns</entry></row><row><entry align="left">Peel strength from the PU varnish after storage for 16 hours at 80 ° C, a peel angle of less than 90 ° and a peel rate of 300 mm / min:</entry><entry align="left">2.8 N / cm</entry></row><row><entry align="left">Peel force from the reverse side at a peel angle of less than 90 ° and a peel rate of 300 mm / min:</entry><entry align="left">0.8 N / cm</entry></row></tbody></tgroup></table></tables>