Edge-Protection Tape

Abstract

A self-adhesive edge-protection tape is intended to improve the protective effect for glass edges. This is achieved by providing an adhesive tape which comprises, in sequence directed towards the substrate to be covered, a backing layer (hard phase) and a soft phase comprising a polymer foam, a viscoelastic composition and/or an elastomeric composition, where the thickness of the hard phase is ≦150 μm, the thickness of the soft phase is ≧200 μm and the ratio of the thickness of the soft phase to the thickness of the hard phase is ≧4. The invention also relates to a solar module which comprises an adhesive tape according to the invention adhesive-bonded around at least one portion of the edges thereof, and the use of the claimed adhesive tape for the protection of edges of a solar module.

Claims

1. An adhesive tape for the protection of glass edges, comprising, in sequence directed towards the substrate to be covered, a hard phase which is a backing layer, and a soft phase consisting of a polymer foam having pressure-sensitive adhesive property, and having a polymer basis selected from polyolefins, polyacrylates, and mixtures thereof, wherein, the thickness of the hard phase is ≦150 μm, the thickness of the soft phase is ≧200 μm and the ratio of the thickness of the soft phase to the thickness of the hard phase is ≧4.

2. The adhesive tape according to claim 1, wherein the hard phase comprises a polymer selected from the group consisting of polyvinyl chlorides, polyethylene terephthalates, polyurethanes, polyolefins, polybutylene terephthalates, polycarbonates, polymethyl methacrylates, polyvinyl butyrals, ionomers and mixtures of two or more thereof.

3. The adhesive tape according to claim 2, wherein the polymer basis of the hard phase is one selected from the group consisting of polyvinyl chlorides, polyethylene terephthalates, polyurethanes, polyolefins and mixtures thereof.

4. (canceled)

5. (canceled)

6. The adhesive tape according to claim 1, wherein the thickness of the soft phase is up to 1800 μm.

7. The adhesive tape according to claim 1, wherein the flexural stiffness of the hard phase is at most 10 mN/mm.

8. A solar module comprising an adhesive tape according to claim 1, wherein the adhesive is bonded around at least one portion of the edges of the solar module.

9. A method for protecting edges of a solar molecule comprising application of an adhesive tape according to claim 1 to a substrate.

10. The adhesive tape according to claim 1, wherein thickness of the soft phase is ≧300-1500 μm.

11. The adhesive tape according to claim 1, wherein the soft phase has a polymer basis of one or more polyacrylates.

Description

EXAMPLES

[0087] Methods:

[0088] A) Measurement of Flexural Stiffness

[0089] The flexural stiffness was determined by using a Softometer KWS from Wolf. A test strip of the material to be tested here measuring 15 mm×75 mm is fixed to the specimen table. The specimen table can be tilted through 30°, in such a way that, during tilting, a medium requiring testing comes into contact with a force sensor. The force determined in mN via the sensor represents a value that can be compared with flexural stiffness.

[0090] B) Dart-Drop Test

[0091] The dart drop test was carried out by a method based on falling-ball tests (for example DIN 52306, 52338) and stone-impact tests (cf. DIN 20567-3). In this test, an object accelerated under gravity falls onto a test substrate, and the resultant damage is evaluated.

[0092] The falling projectile was guided within a tube in order to obtain a precise impact area. The impactor moreover had a defined impact area and impact profile, thus making it possible to study the effect of point loads in comparison with area loads. The kinetic energy on impact was used as controllable variable of the projectile, and can be varied via mass and also via drop height. The energy can either be calculated from the drop height or else determined by way of the projectile's velocity at impact. The velocity was determined by using a light-beam system.

[0093] The impactor used was a stainless steel cylinder with a cut-out. The impact area of the impactor was 90 mm.sup.2, calculated as difference between the area of the base circle of the cylinder and the area of the cut-out. The impactor weighed 400 g.

[0094] The variables measured as results were the extent of damage to the substrate and the extent of damage to the adhesive tape. The studies used the edge of a sheet of float glass of thickness 6 mm to which relevant edge-protection tapes had been applied. The extent of damage to edge-protection tape and glass was the measured variable studied.

[0095] For evaluation of each test, a value was selected from four distinguishable classifications between which clear differences existed.

[0096] These were:

[0097] Classification 1: no damage or only minimal deformation of the protective tape;

[0098] Classification 2: distinct damage to the edge-protection tape, tape penetrated by impact;

[0099] Classification 3: clearly visible penetration of the tape, but no damage to the glass surface;

[0100] Classification 4: damage to the float glass.

[0101] Evaluation was achieved by awarding points for the individual criteria. The first step here was to evaluate the occurrence of damage in classification 4 on a yes/no system. If damage in classification 4 had occurred, zero points were awarded in each of the columns “glass breakage” and “damage”.

[0102] If no damage in classification 4 had occurred, 5 baseline points were then awarded for the “glass breakage” criterion, and were doubled or trebled as appropriate to reflect the drop height of the impactor (1 m, 1.5 m and 2 m). If, therefore, no damage in classification 4 was discernible at a drop height of 2 m, 15 points were awarded for “glass breakage”. The extent of damage to the adhesive tape was also evaluated by using further points. Here, damage in classification 1 was evaluated at 5 points, damage in classification 2 at 3 points and damage in classification 3 at 1 point, in each case under the criterion “extent of damage”.

[0103] Finally, points were also awarded for what is known as “edge lift”, i.e. if the adhesive tape remained in the position surrounding the edges after it had been adhesive-bonded around the edges of the float glass. If this was the case around the entire parameter, 10 points were awarded. If there was clear separation of the adhesive tape from the substrate by departing from the U-shaped position surrounding the edge because of lift of the “arms” of the U, zero points were awarded. Appropriate intermediate assessments were possible by award of 2, 4, 6 or 8 points (2 points for lift/separation which was severe, although not complete, 8 points for only slight separation).

[0104] The total number of points achieved was calculated. A large number of points corresponds to compliance with the usage criteria, while a relatively low number of points signifies defects. The maximum number of points achievable in accordance with the descriptions above was 30. Table 1 collates the results.

[0105] Hard and soft phases:

[0106] Hard phase H1: PET foil of thickness 12 μm

[0107] Hard phase H2: PET foil of thickness 75 μm

[0108] Hard phase H3: PE foil of thickness 135 μm

[0109] Hard phase H4: HDPE foil of thickness 35 μm

[0110] Hard phase H5: PU foil of thickness 300 μm

[0111] Soft phase S1: Foam of density 140 kg/m.sup.3 made of PE-EVA blend (70% by weight of PE, 30% by weight of EVA), thickness 400 μm; provided with a resin-modified pressure-sensitive polyacrylate adhesive composition of thickness 50 μm respectively on the upper and lower side

[0112] Soft phase S2: Foam of density 140 kg/m.sup.3 made of PE-EVA blend (70% by weight of PE, 30% by weight of EVA), thickness 800 μm; provided with a resin-modified pressure-sensitive polyacrylate adhesive composition of thickness 50 μm respectively on the upper and lower side

[0113] Soft phase S3: Self-adhesive polyacrylate foam of thickness 800 μm

[0114] Soft phase S4: Polyacrylate foam of thickness 1000 μm, provided with a resin-modified pressure-sensitive polyacrylate adhesive composition of thickness 50 μm respectively on the upper and lower side

[0115] To the extent that the Comparative Examples used no (inventive) soft phase, the hard phases were adhesive-bonded on the substrate by using a resin-modified pressure-sensitive polyacrylate adhesive composition of thickness 50 μm.

TABLE-US-00001 TABLE 1 Dart-drop test results Hard Soft Drop Glass Extent of Edge No. phase phase height breakage damage life Σ According to the invention 1 H1 S2 2 m 15 1 10 26 2 H1 S4 2 m 15 1 8 24 3 H2 S3 2 m 15 3 8 26 4 H2 S4 2 m 15 3 10 28 5 H3 S1 2 m 15 1 10 26 6 H3 S2 2 m 15 1 10 26 7 H3 S3 2 m 15 1 8 24 8 H4 S3 2 m 15 1 8 24 9 H4 S2 2 m 15 1 10 26 Comparison 10 H5 none 2 m 0 0 10 10 11 H2 none 2 m 0 0 8 8 12 H4 none 2 m 0 0 10 10 13 none S2 2 m 0 0 10 10