WO2017216379A1

WO2017216379A1 - Polymer for an anti-fouling layer

Info

Publication number: WO2017216379A1
Application number: PCT/EP2017/064839
Authority: WO
Inventors: Andreas Brinkmann; Jill Nieradzik
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2016-06-17
Filing date: 2017-06-16
Publication date: 2017-12-21
Also published as: DE102016210863A1; EP3472226A1

Abstract

The invention relates to a polymer for an anti-fouling layer, which polymer can be produced by reacting a thiol with one or more coupling partners of the thiol, wherein the thiol and the one or more coupling partners are selected in such a way that the polymer comprises ≥ 30 wt% of hydrophobic blocks and ≥ 5 wt% of hydrophilic blocks, in each case in relation to the total weight of the polymer, wherein the hydrophobic blocks each comprise ≥ 10 hydrophobic functions and the hydrophilic blocks each comprise ≥ 3 hydrophilic functions.

Description

Polymer for an antifouling layer

The invention relates to a polymer for an antifouling layer, producible by the reaction of a thiol with one or more coupling partners of the thiol, wherein the thiol and the coupling partner are chosen so that the polymer over a certain proportion of hydrophobic blocks and over a certain proportion of hydrophilic blocks. The invention further relates to a mixture for producing such a polymer and to the use of such a polymer for an antifouling coating. Moreover, the invention relates to a process for the preparation of a corresponding polymer.

Surfaces are colonized in the presence of micro and or macroorganisms in natural waters or technical media such as cooling circuits within a very short time. Thus, it comes to the growth of biofilms to the growth of high biomass, which can lead to a significant restriction of objects, vehicles or buildings.

The following points show the problem, which is caused by the colonization of surfaces:

Gaining weight (eg in vehicles, ships and boats), Change in surface, increase in roughness change in hydrodynamic behavior, which in turn leads to increased fuel consumption, eg in ships,

Impairment of maneuverability / steering of ships up to a complete loss,

Environmental aspect of species displacement and destruction of ecosystems,

Surface damage e.g. of protective layers, which can lead to increased corrosion and thus to a reduction in the life of objects, components, vehicles and buildings and / or to increased maintenance costs,

Reduction in flow or blockage of piping in technical installations, which can lead to failure of these

Power loss of equipment (cooling capacity of heat exchangers).

In order to avoid or at least reduce the colonization of surfaces by microorganisms, essentially three methods are known in the prior art: a) The use of biocides in the medium of technical installations. In this case, biocides are added to the (optionally) contaminated by microorganisms medium to kill them or as a prophylaxis against the accumulation of such microorganisms.

A disadvantage of this method is that thereby biocides are released at least in the medium, so that the corresponding media can not be readily disposed of in the environment. In addition, it is regularly necessary to post-dope biocides, which is technically complex and costs. b) Use of biocide-containing coating as so-called antifouling coatings. Here, the surfaces to be protected are coated with a biocide-containing coating material which releases biocide on the surface by different mechanisms of action and kills organisms located there. A disadvantage of this method is that significant amounts of biocide are released into the respective medium and the corresponding coatings "bleed" in the long term if all the biocide has been released c) The use of biocide-free coatings based on silicones or other hydrophobic coating materials The purpose of the surface design is to cause reduced attachment of organisms without killing them, often causing a reduction in the force required to remove microorganisms from the surface.

Although these coatings contain no biocides, but regularly unbound hydrophobic substances such as silicones, so that bleeding or release is also possible here. An example of such a coating is disclosed (Dr. M. Nendza, Examining the Effects on the Marine Environment of Silicone Oils Used in Antifouling / Foul Release Products, ISSN 1862-4804, page 23). Furthermore, it is disadvantageous that the anti-fouling coatings known in the prior art, in particular those of group c), can be applied regularly only in a single way.

Against this background, it was an object of the present invention to provide a coating material that causes a vegetation-inhibiting effect without the release of substances, so that the risk of bleeding is not given. Furthermore, the use of biocides in the medium should not be necessary.

Preferably, the coating material according to the invention should be curable by various mechanisms in order to be able to take account of different application requirements. This object is achieved by a polymer for an antifouling layer, producible by the reaction of a thiol with one or more coupling partners of the thiol, wherein the thiol and the coupling partner or partners are selected so that the polymer> 30 wt .-% hydrophobic blocks and > 5% by weight of hydrophilic blocks, based in each case on the total weight of the polymer, the hydrophobic blocks each having> 10 hydrophobic functions and the hydrophilic blocks each having> 3 hydrophilic functions and the thiol comprising at least two thiol groups. Hydrophobic blocks within the meaning of the present invention are those portions of the polymer which (by themselves) have water-repellent properties.

Hydrophilic blocks in the context of the present invention are those subregions of the polymer which (considered alone) have hydrophilic properties.

Water-attracting or water-repellent means that the respective pure substance as a coating material of a surface has a static water edge angle of> 90 ° (water-repellent) or <90 ° (water-attracting).

The hydrophobic blocks within the meaning of the present invention, which are counted on the respective weight fraction, comprise in each case> 10, preferably> 50, more preferably> 100 hydrophobic functions and the hydrophilic blocks which are counted for the respective weight fraction comprise> 3 in each case, preferably> 10 and more preferably> 20 hydrophilic functions.

The length of a hydrophobic block is determined in each case by a limiting hydrophilic function (terminal block) or two such functions, always viewed along the main chain of the polymer.

The length of a hydrophilic block is determined by the limitation of a hydrophobic function (terminal block) or two such functions, each along the main chain of the polymer.

Hydrophobic and hydrophilic functions are group or chain constituents which in each case impart the hydrophobic or hydrophilic property to the respective block. Preferred hydrophilic and hydrophobic functions are listed below.

It has surprisingly been found that the polymers according to the invention have a surprisingly good effect on inhibition of growth. This is - without being bound by theory - attributed to the respective proportions of hydrophilic and hydrophobic blocks in the polymer. The antifouling property of coatings of the polymer according to the invention is preferably determined according to ASTM D3623-78a (2012) "Standard Test Method for Testing Anodizing Panels in Shallow Submergence". A further advantage of the polymers to be used according to the invention is that they are curable (polymerizable) in two ways and can thus form very different mechanical, physical and chemical structural properties on the surface.

It will be understood by those skilled in the art that for the monomers of the polymer according to the invention, those compounds are suitable which comprise more than one thiol group, preferably two thiol groups. It is also comprehensible to the person skilled in the art that it is likewise preferred for the coupling partners of the thiol that they are in monomers which have a plurality of coupling partners, preferably two coupling partners. This results in block copolymers, in general it is preferred in the context of the present invention that the polymer according to the invention is a block copolymer.

Preferred coupling partners of the thiol are selected from the group consisting of acrylic group, vinyl group, isocyanate group and epoxy group.

For the purposes of the present invention, preference is given to the hydrophilic blocks forming> 40% by weight and / or the hydrophilic blocks> 10, more preferably> 15% by weight of the polymer.

For the polymer according to the invention it is preferred that the hydrophobic functions of the hydrophobic blocks are selected from the group consisting of hydrocarbon radicals, fluorinated hydrocarbon radicals, siloxane radicals, fluorinated siloxane radicals and silazane radicals.

Siloxane radicals are particularly preferred in this context as hydrophobic functions.

Preferred within the meaning of the present invention is a polymer according to the invention, wherein the hydrophilic functions of the hydrophilic blocks are selected from the group consisting of glycol radicals, ether radicals, ester radicals, amine radicals and amide radicals.

Glycol radicals are particularly preferred in this context as hydrophilic functions.

In the case of the respective functions, it is possible that these are either part of the main chain of the polymer (backbone) or that they are present as side chains. It should be noted, however, that for the classification into a hydrophilic or hydrophobic block in each case the effect of the chain constituent is to be assessed with its entire residues.

Preferred within the meaning of the invention is a polymer according to the invention, wherein the hydrophilic functions in the hydrophilic blocks are glycol radicals and / or the hydrophobic functions in the hydrophobic blocks are siloxane radicals and / or the coupling partner of the thiol group is an acrylic group.

It is very particularly preferred in this connection that the monomers from which the polymer according to the invention is formed comprise two coupling functions or two thiol groups.

The preferred coupling function of a thiol is generally an acrylic group.

For the purposes of the invention it is preferred that a polymer according to the invention is formed partly by radiation-induced and partly by ion-induced mechanism. A preferred ion-induced mechanism is an addition reaction. By mixed polymerization with different mechanisms, it is possible to adjust the desired surface functions and properties in a particularly suitable manner. In particular, it is possible to select a suitable mechanism for the appropriate processing form. For example, it is preferred that the coating resulting from the polymer comprise a microstructure. In this case, at least partial radiation curing (radical polymerization) is helpful in structuring.

In this context, a microstructure is understood to mean a structure introduced on the micrometer scale or sub-micrometer scale by means of printing, pressing or molding processes. This structure is introduced by a suitable tool, e.g. a transparent stamp containing a negative structure of the microstructure.

For applying this microstructure, in many cases it is preferred that a radiation-curing mechanism be chosen. The polymer according to the invention thus makes it possible to use very similar polymers (namely from the same monomers formed) in various ways. For example, it is possible to use the same monomer mixture for different application conditions.

Accordingly, a part of the present invention is a mixture for the preparation of a polymer for an antifouling layer according to the invention comprising a thiol and a coupling partner for the thiol, each as defined above.

With this mixture, there is the advantage that the curing mechanism can be adapted to the application requirement.

Particularly preferred in this context is a mixture according to the invention, further comprising a compound for starting an ion-induced polymerization (eg a catalyst) and / or a compound for starting a radiation-induced polymerization.

Preferred compounds for starting an ion-induced polymerization in this case are amines, phosphines and generally Lewis acids such as gadolinium (III) triflates or tetrafluoroborates.

Preferred compounds for initiating radiation-induced polymerization in this context are α-hydroxy, α-alkoxy or α-aminoaryl ketones, e.g. o hydroxyketone and azo compounds or acylphosphine oxide.

In particular, when both types of compounds are present for starting in the mixture according to the invention, it is possible either to choose the respective Aushärungsme- mechanism or use both curing mechanisms, possibly even in parallel. Thus, by selecting the concentration of the initiator compound and the different reaction rates of photocatalysis and ionic catalysis crucial influence on the polymerization can be taken, for example, to generate surface equilibrium reactions (solubility effect) or geometric structures by embossing / pressure application techniques (Riblett structuring).

Part of the invention is also the use of a polymer according to the invention for an antifouling coating. It is preferred in this context that the anti-tarnish coating consists of> 90% by weight, more preferably completely of the polymer according to the invention. Part of the invention is also a process for the preparation of a polymer according to the invention comprising the steps: a) providing a mixture according to the invention or the individual constituents of such a mixture and b) polymerizing the thiol and the coupling partner of the thiol by means of an ionic and / or radiation-induced mechanism.

As already indicated above, the polymer according to the invention can be produced for a growth-inhibiting coating by the process according to the invention. The curing mechanisms can be selected, it being understood that the type of curing (polymerization) can be influenced by adding starter compounds for the particular polymerization mechanism.

As already discussed above, antifouling coatings can be prepared with the polymers according to the invention. Preferred substrates for the antifouling coatings of the polymers according to the invention are surfaces which are in permanent contact with water or building surfaces.

Preferred within the meaning of the present invention are the surfaces in contact with water of ships, bridges and other permanent water contact structures, the surfaces of water tanks and the surfaces of heat exchangers

It is preferred in this context that a substrate coated according to the invention, measured according to ASTM D3623-78a (2012), remains free of growth by microorganisms for one year. Examples

example 1

Coating of a substrate with a polymer according to the invention

(ion-induced polymerization)

Table 1

Implementation (with reference to Table 1)

Position 1 is presented in a suitable vessel. Gradually, positions 2 and 3 are added. Just before the application, positions 4 and 5 are added. Last, position 6 is added. Then the material is stirred (Speedmixer 200 rpm / 6 min) until a homogeneous mixture is obtained. Then the material can be applied (eg spraying, brushes, rollers, printing, etc.). As a substrate, organic surfaces such as plastics or other paint layers, inorganic surfaces such as glass or ceramics, natural materials such as wood or metallic surfaces can be used. Each forms a solid coating. Example 2

Coating of a substrate by means of a polymer according to the invention

(radical polymerization)

Table 2 Procedure (with reference to Table 2)

Position 1 is presented in a suitable vessel. Gradually, positions 2 to 6 are added. Then the material is stirred (Speedmixer 200 rpm / 6 min) until a homogeneous mixture is obtained. Then the material can be applied (eg spraying, brushes, rollers, printing, etc.). After the acetone has escaped, the applied film can be cured with a UV source such as a mercury vapor lamp. As a substrate, organic surfaces such as plastics or other paint layers, inorganic surfaces such as glass or ceramics, natural materials such as wood or metallic surfaces can be used. Each forms a solid coating. Example 3

Coating of a substrate with a polymer according to the invention

(ionic and radical polymerization)

Table 3

Implementation (with reference to Table 3)

Position 1 is presented in a suitable vessel. Gradually, positions 2 to 4 are added. Just before the application positions 5 and 6 are added. Last, position 7 is added. Then the material is stirred (Speedmixer 200 rpm / 6 min) until a homogeneous mixture is obtained. Then the material can be applied (eg spraying, brushes, rollers, printing, etc.). After the acetone has escaped, the applied film can be cured with a UV source such as a mercury vapor lamp. In parallel, the ion-induced curing mechanism takes place. As a substrate, organic surfaces such as plastics or other paint layers, inorganic surfaces such as glass or ceramics, natural materials such as wood or metallic surfaces can be used. Each forms a solid coating. Example 4

Coating test without the use of thiols:

Table 4

Procedure (with reference to Table 4)

Position 1 is presented in a suitable vessel. Gradually, positions 2 to 5 are added. Then the material is stirred (Speedmixer 200 rpm / 6 min) until a homogeneous mixture is obtained. Subsequently, the material can be applied (e.g., syringes, brushes, rollers, printing, etc.).

A thus applied material for no curing reaction by which the applied films remained liquid, even after several days.

In this example, it has been found that it is not possible to cure the above composition to a sufficient extent for a coating. Example 5

Auslagerungsversuche to determine the inhibition of growth

To test the effectiveness, 10 × 10 cm PVC test panels were prepared with a coating from Example 1 and outsourced over a breeding season March / May to September / October 2015 off Norderney in the sea. After each month the plate is evaluated for growth according to ASTM D3623 - 78a (2012).

Figure 1 presents the results of the vegetation assessment. Each inspection is one month away from the previous one and the first inspection was taken one month after removal from storage. The fouling rating represents the proportion of the test area unoccupied by microorganisms. It can be seen that considerable fouling is still present even after five months. Similar results were also found for coated with coating according to Example 2 and 3 substrates.

Example 6

Anti-fouling assessment in barnacle rapid test

For the evaluation of antifouling, three samples were offshore off Norderney in an alternate immersion zone. The assessment was based on the number of fishpox larvae picked up, whereby the outsourcing took place one week in the period from 27 May 2016 to 3 June 2016. In each case PVC plates were examined, wherein a PVC plate was coated with the coating of Example 1, the second PVC plate according to the manufacturer with the coating "silicone one fouling release antifouling silicone and hydrogel-based" coated according to the manufacturer Hempel The third PVC sheet was used uncoated and the result is shown in Table 5.

It turns out that the coating according to the invention effectively protects against colonization with barnacle larvae in comparison to the comparative examples. Similar effects were also observed for the coating of Examples 2 and 3.

Table 5

Example "7 Coating of a Substrate with an Alternative Inventive Polymer" A hydrophobic block is a hydrophilic block

Table 6

execution

Position 1 Triethylenediamine is placed in a suitable vessel. Then position 2 butyl acetate is added and the mixture is stirred. Preferably, a laboratory magnetic stirrer at about 500 U / min is used. After position 1 has dissolved in position 2, position 3 diethylenetriamine is added, while the product is stirred further. Thereafter, position 4 glycol di (3-mercaptopropionate) is weighed and the mixture is allowed to stir for 5 minutes at medium speed. Finally, just before application to the substrate of the second coupling partner, the Tegomer® V-Si 2250 (polydimethylsiloxane diacrylate) is added, thereby starting the reaction which is observed by a temperature increase. In particular, the substrates mentioned in Example 1 can be used as the substrate. Each forms a solid coating,

Claims

Expectations

1. Polymer for an antifouling layer, which can be produced by reacting a thiol with one or more coupling partners of the thiol, the thiol and the coupling partner or partners being selected such that the polymer contains >30% by weight of hydrophobic blocks and >5% by weight. -% hydrophilic blocks, each based on the total weight of the polymer, wherein the hydrophobic blocks each comprise >10 hydrophobic functions and the hydrophilic blocks each comprise >3 hydrophilic functions and wherein the thiol comprises at least two thiol groups.

2. Polymer according to claim 1, wherein the coupling partner of the thiol is selected from the group consisting of acrylic group, isocyanic group and epoxy group.

3. Polymer according to claim 1 or 2, wherein the hydrophobic functions of the hydrophobic blocks are selected from the group consisting of hydrocarbon residues, fluorinated hydrocarbon residues, siloxane residues, fluorinated siloxane residues and silazane residues.

4. Polymer according to one of the preceding claims, wherein the hydrophilic functions of the hydrophilic blocks are selected from the group consisting of glycol residues, ether residues, ester residues, amine residues and amide residues.

5. Polymer according to one of the preceding claims, wherein the hydrophilic functions in the hydrophilic blocks are glycol residues and / or the hydrophobic functions in the hydrophobic blocks are siloxane residues and / or the coupling partner of the thiol group is an acrylic group.

6. Polymer according to one of the preceding claims, wherein the polymer was formed partly by radiation-induced and partly by ion-induced mechanism.

7. Mixture for producing a polymer for an antifouling layer according to one of the preceding claims, comprising a thiol, and a coupling partner for the thiol, each as defined in one of the preceding claims.

8. A mixture according to claim 8, further comprising a compound for initiating an ion-induced polymerization and/or a compound for initiating a radiation-induced polymerization.

9. Use of a polymer as defined in one of claims 1 to 6 for an antifouling coating.

10. A process for producing a polymer according to one of claims 1 to 6, comprising the steps: a) providing a mixture according to one of claims 7 or 8 or the individual components of such a mixture, b) polymerizing the thiol and the coupling partner of the thiol by means an ionic and/or radiation-induced mechanism.