WO2018108693A1

WO2018108693A1 - Self-fusing antifouling tape

Info

Publication number: WO2018108693A1
Application number: PCT/EP2017/081814
Authority: WO
Inventors: Serge Sirlereaux; Martine VAN BUTSEL; Gregor PRZYBYLSKI
Original assignee: Renolit Se
Priority date: 2016-12-16
Filing date: 2017-12-07
Publication date: 2018-06-21

Abstract

Elastic, self-fusing tape (1, 1a, 1b) that comprises a carrier layer (3, 3a) based on self-fusing silicone and an antifouling layer (2, 2a) self-fusing to the carrier layer (3, 3a) based on antifouling silicone or a layer (1b) made of a mixture of a self-fusing silicone with an antifouling silicone, and a method for protecting objects (5) under water, comprising providing the elastic, self-fusing tape (1, 1a, 1b) and wrapping the object (5) under tensile load of the tape (1, 1a, 1b).

Description

Self-fusing antifouling tape

The present invention relates to tape-shaped antifouling protection which makes adhesives superfluous and can also be wrapped around objects underwater obtaining an antifouling coating. A multitude of maritime creatures settle on parts which are in contact with seawater for long periods of time, which is referred to as fouling. Above all, algae, mussels and barnacles present a great problem; the growth of these organisms is difficult to remove. In order to prevent such growth, various means are known, above all for ships, boats, etc. Thus, a biocidal antifouling paint is traditionally applied to the underwater surfaces of ships. The application of films having a particularly smooth surface or a specifically structured surface (e.g. fibres or an embossing) or those that are coated with antifouling paint has been proposed. With these more recent antifouling measures, renewal can be simpler and the smooth or specific surfaces can also enable avoiding or at least reducing biocidal antifouling substances.

Fouling does not only concern ships, but also fixedly installed equipment, such as pipes, linkage and cables. In contrast to ships, painting with antifouling paints or adhering antifouling films is laborious and thus also expensive. Replacing the antifouling means is even more difficult. In order to protect objects having bent surfaces, antifouling tapes have therefore already been proposed which can be applied more easily to bent surfaces, e.g. can be wrapped around pipes and rods. Thus, in US 2014/0377552 A1 , a multilayer antifouling tape is described in which a base layer is coated on one side with an adhesive and, on the other side, with a silicone layer which contains an antifouling substance; among other things, silicon oils, waxes and fats are mentioned. The base layer can comprise a polyurethane, a polyurethane acrylic resin, a rubber, a polyvinyl chloride, a polyester, a silicone, an elastomer and others, and can be single- or multi-layered. From JP 2001 -220524, a coating composition is known which comprises antifouling particles in a binder. The binder can either be applied to the surface to be protected or to a film. If a film is used, this is to be applied to the surface to be protected by means of adhesive. Materials based on silicon are preferred for both the binder and the adhesive.

These known tapes and films are difficult to remove when they cease to be effective and a replacement is necessary. Application underwater is not possible since the water film that adheres to the object to be protected prevents a useful adhesion. Surprisingly, it was now found that these problems can be solved by so-called self- fusing tapes, when an antifouling layer self-fusing to a carrier layer is applied to the carrier layer. Alternatively, single-layer tapes, which have the elasticity, tensile strength and adhesion to one another of self-fusing silicones and the antifouling effect of antifouling silicones, are possible. Single-layer, self-fusing tapes have been known for quite a while, see US

3,006,463 A, DE 197 36 668 A1 , KR 2009 0028751 A and US 2013/0095300 A1 , for example. They are based on silicones and serve to isolate and shield electrical lines. Such tapes are commercially available, e.g. under the name "Stretch & Seal" by Berry Plastic Corp., USA, and are also advertised for sealing tubes and for protecting pipes from rust and corrosion. In contrast to tapes with contact adhesives (or other adhesives), an adhesive connection is only obtained between the layers of the material. A force-fit connection results with the wrapped surfaces. For this, the tapes are very elastic, such that the restoring force permanently ensures a force closure between tape and surface. As a result, the tapes can be removed without leaving residue by simply cutting them along the wrapped object.

The invention thus solves the problems mentioned above by means of an elastic, self-fusing tape which comprises a carrier layer based on self-fusing silicone and an antifouling layer self-fusing to the carrier layer based on antifouling silicone. Alternatively, the tape is a single layer and comprises a mixture of antifouling silicone and self-fusing silicone. The tape according to the invention is free from adhesives or adhesive layers, which form an adhesive connection to other surfaces. The adhesion of the layers to one another is based only on the principle of self-fusing; an adhesive connection to other surfaces does not take place (unless the other surface has adhesive properties).

The invention further solves the object of protecting pipes, rods and other elongated objects underwater by wrapping these with an elastic, self-fusing tape that comprises a carrier layer based on self-fusing silicone and an antifouling layer self-fusing to the carrier layer based on antifouling silicone or a layer containing a mixture of antifouling silicone and self-fusing silicone, under tensile load on the tape.

Suitable objects are all those that can be wrapped. Typically, these are elongated objects, i.e. objects that have a length that is significantly greater than the cross- section. For example, pipes and rods, wherein both round and rectangular or even differently shaped cross-sections are possible. Of course, short piping pieces or bars can be wrapped, the length of which is less than their cross-section. It is important that the object does not have any overly flat surfaces or surfaces that are barely arched. The material of the object is not important since it is neither necessary nor desired for the tape to adhere to the object.

The tape according to the invention is elastic and self-fusing.

Here, elastic means a tear elongation measured according to DIN 53504 S1 of at least 200%, preferably at least 300% and in particular at least 500%. The upper limit is not determined by the use, but by the necessary stability of the material; it is typically at about 1000%. Furthermore, the tape has a restoring force measured according to DIN DIN 53512 of 20%, in particular of 60%, by means of which the force-fit sealing on the wrapped object is ensured. The tear strength measured according to DIN 53504 S1 is usually at least 5 MPa, preferably at least 7 MPa and in particular at least 9 MPa. Here too, the upper limit is determined by the material. Self-fusing means materials that form an adhesive connection with themselves, yet, in contrast to adhesives, do not adhesively connect to other surfaces. In this respect, self-fusing tapes up until now have been formed to have a single layer or had two identical external layers. In one preferred embodiment, the tape according to the invention has two different layers, since the carrier layer is not an antifouling layer. It is nevertheless self-fusing, since the material of the two layers is based on silicone. In the alternative embodiment, surprisingly, sufficient self-fusing despite the dilution of the self-fusing silicone with the antifouling silicone is achieved.

Based on silicone means that silicone is contained in such an amount that its mechanical properties define those of the layer and fusing layers is made possible. Typically, fillers and excipients are contained besides the silicone.

Suitable silicones, also called silicone elastomers or polyorganosiloxanes, are polymers made of bifunctional organosiloxanes, which are crosslinked by means of peroxides or with acetoxy or oxime crosslinkers, for example. Elasticity and adhesive capability of a layer are set in an inherently known manner by means of the amount of crosslinker. The crosslinking can take place at room temperature (RTV silicones) or preferably at an increased temperature (HTV silicones) of at least 80°C, e.g. up to 180°C.

The materials of the carrier layer and the antifouling layer are selected in such a way that the two layers have an adhesive strength according to DIN 53 357/A of at least 1 N/5cm, preferably at least 2 N/5cm and particularly preferred 5 N/5cm. With single layer tapes, so much self-fusing carrier silicone is used that the adhesive strength is at least 1 N/5cm. For the carrier layer or as the carrier silicone, silicone rubber crosslinked by peroxides, so-called HTV silicones, are preferred. The carrier layer or the carrier silicone gives the tape according to the invention its elasticity and tear strength and is also responsible for the necessary restoring force. Thus, the values of the carrier layer for the tear extension and tear strength are in the ranges for the tape mentioned above. The thickness of the carrier layer is preferably from 300 μιτι to 1 mm, particularly preferred from 450 μιτι to 850 μιτι, for example about 650 μιτι. Well suited are silicones which are commercially available under the name

ELASTOSIL R™, e.g. ELASTOSIL® R 6225, ELASTOSIL® R 6550, ELASTOSIL® R 101/25, ELASTOSIL® R 101/35, ELASTOSIL® R 101/45, ELASTOSIL® R

401/10, ELASTOSIL® R 401/20, ELASTOSIL® R 401/30 OH and ELASTOSIL® R 401/30 S from Wacker Chemie AG, DE. Furthermore, the HTV silicones Addisil 140 E, Addisil 440 E, Addisil 442 E, Tufel II 94406, Tufel II 94405, Addisil IND 1040 E and Addisil IND 2040 E from Momentive Performance Materials Inc., US and the HTV silicones XIAMETER® RBB- 2000-35 Base, XIAMETER® RBB- 2002-30 Base, XIAMETER® RBB- 2002-70 Base, XIAMETER® RBB- 2300-30 Base, XIAMETER® RBB- 2030-40 Base and XIAMETER® RBB- 2220-55 Base from DOW Corning Corp., US, and HTV silicones from Shin-Etsu Siliconesof America, Inc., US are well suited. The antifouling layer is preferably produced from cold-crosslinked antifouling silicones, for example 1 K, 2K or 3K silicones, e.g. with acetoxy or oxime

crosslinkers. The mechanical properties of the antifouling layer are chosen in such a way that the elasticity of the carrier layer is not impaired, i.e. the tear extension is generally higher than for the carrier layer. The tear strength of the antifouling layer is less important and its restoring force does not play a role. The thickness of the layer is typically from 100 μιτι to 150 μιτι.

A silicone is used which can be obtained on the market as an antifouling silicone. Any antifouling silicone can be used that has a maximum fouling rate of 5% when measured statical for at least 1 year, preferably at least 1 .5 years and particularly preferred at least of 2.5 years, according to ASTM 6990-03 in connection with ASTM 3623-78a. Fouling rate means the surface area of the sample that is covered by the growth. Silicones not especially provided with an antifouling effect, such as the self-fusing carrier silicones, for example, usually have a fouling rate of less than 5% for 6 months maximum. Mostly, the fouling rate after one year is 100%, i.e. the test sample is completely overgrown.

The antifouling layer can contain a biocidal substance. All biocides known as such can be used, for example copper and copper compounds (e.g. copper dioxide, copper pyrithione, copper thiocyanate), zinc pyrithione, isothiazolinones, dichlofluanid and tolylfluanid as well as tralopyril and medetomidine. Such antifouling silicones are described, for example, in EP 2 516 559 B1 and in the prior art described there.

It is preferred that the antifouling layer does not contain biocidal substances; the antifouling effect of such antifouling silicones is based on their composition.

Well suited silicones for the antifouling layer are, for example, SILIC PRO 77460, HEMPAGUARD 89909, SILIC ONE 77450, HEMPASIL X5, HEMPASIL 77500, HEMPASIL X7, HEMPASIL Nexus and HEMPASIL X3+ 87509 with crosslinker 98980 and 98951 (Hempel A/S, DK), Intersleek 1 100 SR made of parts A, B, C and Intersleek 970, Intersleek 757, Intersleek 425, Intersleek 900 (International Paint Ltd., GB), Sea lion, Sea lion repulse, Sea lion resilient (Jotun (Germany) GmbH) and Sigmaghde 120, Sigmaghde 890, Sigmaghde 790 und Sigmaghde 990 (PPG Industries, Inc., US).

Typical widths of the tape are from 5 cm to 50 cm, preferably up to 30 cm, particularly preferred from 10 to 20 cm. The width constitutes a compromise: the wider the tape, the more of the surface that is covered by one wrapping. However, during wrapping, a sufficient tension must be exerted on the tape, which requires more and more force as the width increases. The length is not particularly limited; the rolls should be able to be handled, but must not have to be fixed too often. In this respect, lengths of 5 to 200 m, preferably 20 to 100 m, and particularly about 50 m are well suited. The particular advantage is that, by means of the tape according to the invention, a protection can also be produced on objects that are underwater. Wrapping under tensile load sufficiently presses out the water between object and tape as well as between the windings of the tape; small left-over quantities do not impact the self- fusing. Adhering to the object is not the aim; the tape is held in a force-fit manner by its elasticity by means of the restoring force.

When wrapping, a tensile load of the tape is to be maintained. Usually, when wrapping, an overlap of the tape (i.e. the winding layers) of 30 to 70%, preferably of about 50%, is provided.

In a particularly preferred embodiment, the antifouling layer does not cover the entire carrier layer, but rather substantially only the part of the carrier layer that is exposed after wrapping. Accordingly, the antifouling layer covers about 35 to 75%, preferably 55%, of the carrier layer. As a result, the amount of the more expensive antifouling silicone can be reduced without forfeiting the effect. The surface of the tape overlapped by the carrier layer does not contribute to the antifouling effect and, accordingly, can be implemented without an antifouling layer. A further advantage is an optimised adhesion. It is advantageous if the silicone of the carrier layer has a different colour or colour intensity to the antifouling silicone. This makes it easier for the user to correctly wrap the tape around the object to be protected. Furthermore, single-layer tapes can be used in which a silicone tape is obtained by mixing a sufficiently elastic and tear-resistant silicone with an antifouling silicone, said silicone tape having a fouling rate of a maximum of 5%, measured statistical according to ASTM 6990-03 in connection with ASTM 3623-78a and a tear extension according to DIN 53504 S1 of at least 200% and a tear strength according to DIN 53504 S1 of at least 5 MPa and a restoring force according to DIN 53512 of at least 20%. The antifouling silicones mentioned above are designed as painting agents and typically have a tear extension of only 120% and a tear strength of 2 - 2.5 MPa, which does not produce tapes that can be used for wrapping.

Mixtures of at least 50% by weight of antifouling silicone with a silicone suitable for the carrier layer, as they have been described above, have proved to be useful. The maximum amount of antifouling silicone depends on the mechanical properties of the antifouling silicone. If this already results in elastic and tear- resistant layers, then up to 90% by weight can be contained. If the resulting layers, however, are barely elastic and tear-resistant, a maximum of 60 or 70% by weight should be contained. Tapes according to the invention can be produced in a known manner as such. Preferably, the material of the carrier layer is applied to a release liner and this layer is subsequently coated with the material of the antifouling layer, or vice versa. The materials are then, e.g. in the case of HTV silicones, additionally crosslinked by heating in a dry oven. Alternatively, the carrier layer and the antifouling layer can be produced separately on release liners and then brought together in a roller gap by means of pressure to form the tape according to the invention. Many silicones can be extruded, such that the tape can also be produced by means of co-extrusion, or individual layers can be extruded. The tape is wound to a roll with at least one release liner. Suitable release liners are known to the person skilled in the art; those based on polyester or polyethylene, for example, are well suited. As usual, the production can take place in greater widths, the tapes are brought to the desired width before rolling up by means of cutting in the machine direction. It is a great advantage of the invention that the present tape can be easily removed in order to renew the protection. It is sufficient to cut the layers along the object, e.g. by means of a knife, and then to take them away. Since no adhesion is formed between the tape and the object, it is also not necessary to clean the surface. Fouling organisms on the old tape are removed along with it. The new tape is simply wrapped around the object after removing the old, sliced tape.

The invention is explained in more detail with reference to the enclosed figures, though without being limited to the embodiments concretely shown. The invention also relates to all combinations of preferred embodiments, so far as these are not mutually exclusive. The indications "about" or "approx." in connection with a number mean that values at least 10% higher or lower or at least 5% higher or lower and, in any case, at least 1 % higher or lower are also included.

Here are shown

Figure 1 , a tape according to the invention made of a carrier layer and an antifouling layer;

Figure 2, a tape according to the invention made of a carrier layer and an antifouling layer that is less wide;

Figure 3, a tape according to the invention having a layer made of a mixture of antifouling silicone and self-fusing carrier silicone;

Figure 4 shows a pipe which is wrapped by the tape from Figure 1 ; and

Figure 5 shows a pipe which is wrapped by the tape from Figure 2.

In Figure 1 , a tape 1 according to the invention made of a carrier layer and an antifouling layer is schematically depicted in cross-section. It comprises the carrier layer 2 made of self-fusing silicone and the antifouling layer 3 made of antifouling silicone. Figure 2 illustrates a preferred embodiment of a tape 1 a according to the invention made of a carrier layer 2a and an antifouling layer 3a, in which the antifouling layer 3a has a smaller width than the carrier layer 2a.

Figure 3 shows an alternative tape 1 b according to the invention, in which only one layer 4 made of a mixture of antifouling silicone and self-fusing silicone is present.

In Figures 4 and 5, a section of a pipe 5 is shown, which, according to the invention, is protected from growth by wrapping with the tape. In Figure 4, the tape from Figure 1 was used; the overlap of the tape 1 is indicated by dashed lines. In Figure 5, the tape from Figure 2 was used; the overlap of the tape 1 a is, in turn, indicated by dashed lines. The antifouling layer 2a is not as wide here as the tape 1 a. The border, up to which the antifouling layer 2a extends, is indicated by dotted lines; the carrier layers 3a lie directly next to one another in the region between the dotted line and the end of the tape 1 a. By doing so, on the one hand, the self- fusing property is increased and, on the other hand, costs for expensive antifouling silicone can be saved.

List of reference numbers

1 , 1 a Tape having a carrier layer and an antifouling layer

1 b Single layer tape

2, 2a Carrier layer

3, 3a Antifouling layer

4 Layer made of a mixture of carrier silicone and antifouling silicone

5 Pipe

Claims

1 . Elastic, self-fusing tape which comprises a carrier layer based on self-fusing silicone and an antifouling layer self-fusing to the carrier layer based on antifouling silicone or a layer made of a mixture of a self-fusing silicone with an antifouling silicone.

2. Tape according to claim 1 , wherein the tape is free from adhesives or

adhesive layers, which form an adhesive connection to other surfaces except for those based on silicone.

3. Tape according to claim 1 or 2, wherein the tape has a tear extension

measured according to DIN 53504 S1 of at least 200%, preferably at least 300% and particularly preferably at least 500%, and a return force measured according to DIN 53512 of > 20%, in particular of > 60%, and a tear strength measured according to DIN 53504 S1 of at least 5 MPa, preferably at least 7 Pa and in particular at least 9 MPa.

4. Tape according to one of claims 1 to 3, wherein the antifouling layer contains at least one biocide, in particular selected from copper and copper

compounds, preferably copper dioxide, copper pyrithione, copper

thiocyanate; zinc pyrithione; one or more isothiazolinones; dichlofluanid; tolylfluanid; tralopyril; medetomidine and mixtures of two or more thereof.

5. Tape according to one of claims 1 to 3, wherein the antifouling layer does not contain biocides.

6. Tape according to one of claims 1 to 5, wherein the silicone is a crosslinked polymer made of bifunctional organosiloxanes.

7. Tape according to claim 6, wherein the silicones are crosslinked by means of peroxide or by means of acetoxy and/or oxime crosslinker.

8. Tape according to one of claims 1 to 7, wherein the silicone of the carrier layer is a peroxide-crosslinked polyorganosiloxane.

9. Tape according to one of claims 1 to 8, wherein the silicone of the antifouling layer is a polyorganosiloxane crosslinked by acetoxy and/or oxime crosslinker.

10. Method for protecting objects under water, comprising:

- providing an elastic, self-fusing tape that comprises a carrier layer based on a self-fusing silicone and an antifouling layer self-fusing to the carrier layer based on antifouling silicone or a layer made of a mixture of a se!f- fusing silicone with an antifouling silicone,

- wrapping the object under tensile load of the tape.

11. Method according to claim 9, characterised in that the object is a pipe or a rod.