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(11) | EP 1 529 613 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method for a protective treatment of thatch |
| (57) The invention describes a method for a protective treatment of thatch against growth
of algae. This is done by dipping the thatch in a composition comprising a silicone
compound according to one of the formulas I-IV: (R1O)nSi(R2)3-n (I) (R2)3Si - O - Si(R2)3 (II) or wherein R1 is H, C1-C20 alkyl or C6-C20 aryl; R2 is C1-C20 alkyl, C1-C20 alkoxy, C6-C20 aryl or C6-C20 aryloxy; R3 is H, C1-C20 alkyl, C1-C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy; R4 is OH, C1-C20 alkyl, C1-C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy; n is 1-4, provided that n=1 if R1 is H; m is 2-100; o is 3-100; at a temperature between 0 and 200°C, wherein said method improves the water resistivity of the thatch. Algae growth on thatched roofs based on such thatch is prevented. The method of the invention can advantageously be combined with a treatment with fire retardants. Thatch can also be sprayed or treated with a fluid or gas, respectively, that improves the water resistivity of the thatch. |
[0001] The invention is related to a method for a protective treatment of thatch. Further, the invention is related to thatch, subjected to such treatment.
Background
[0002] Thatched roofs have been built for a long time and are very popular in some countries, like e.g. the UK or the Netherlands. The advantage of thatched roofs is that the insulation properties are very good. Thatched roofs are also popular because they are entirely made of natural materials and provide a pleasant appearance.
[0003] A disadvantage of thatched roofs is that algae often grow on the surface of the roof but also the internal of the thatched roof, such that a (bio)degradation process takes place inside the thatch layer of the roof. This may dramatically reduce life expectancy. Further, the presence of algae, moss and dirt is also undesirable from an aesthetic point of view.
[0004] In order to prevent the growth of algae on thatched roofs, thatched roofs are coated or otherwise treated with algicides, e.g. by a spraying process. As algicides, quartenary ammonium compounds may be used. Here, a disadvantage is that such algicides may easily be washed away from the surface of the thatched roof by rainfall. Further, such treatment appears only to be effective for 1-2 years. Next to that, some algicides may damage, decolor or otherwise harm the thatched roof.
[0005] Coating thatched roofs with protective fluids is e.g. known from GB 2105382. The document describes a complicated way for protecting thatched roofs: shrouding the thatch in a relatively lightweight cover which will prevent any appreciable amount of fluid from escaping (other than via any fluid outlet lines leading off from the cover); spraying the thatch, under the cover with the fluid, the spray being sufficiently pressurised for the fluid to penetrate beyond the upper (or lower) surface envelope of the thatch but not so pressurised as to cause the fluid to dislodge any appreciable portion of the thatch during spraying; and removing the cover to expose the thatch once again to the atmosphere. Due to the fact that this method is rather complicated, it is not often applied. Further, though the area between the thatch stems may be coated better than by a less elaborate coating, the coating may still be washed away by rainfall. This document does not describe how to prevent algae formation and/or growth.
[0006] Thatch on thatched roofs may also be coated with e.g. lacquers to provide a protective layer. A disadvantage of such layers is that they may change the colour of the thatch leading to a thatched roof without its natural colour. Another disadvantage is that the duration of the protection of such layers is generally limited for only about 1-2 years, due to wear of the coating (e.g. by UV light and natural fragmentation of the thatch). A further strong disadvantage of such coatings is that moisture retention in the thatch layer occurs, leading to increased algae problems after a number of years.
[0007] Another disadvantage of thatched roofs is that they are regarded as less safe in case of fire than conventional roof materials. To solve this problem thatched roofs are often sprayed with a fire retardant. Such fire retardant coatings are for example described in DE 19727998 and NL 9101915. The drawback of spraying fire retardants is that they may easily be washed away from the surface of the thatched roof by rainfall.
[0008] Hence, it is an object of the invention to provide a method for a protective treatment of thatch against growth of algae, that does not suffer, or suffers less, from one or more of above mentioned problems with respect to the formation of algae. In a further aspect of the invention, it is an object to provide a method for a protective treatment of thatch against growth of algae and against fire.
Description
[0009] According to the present invention there is provided a method for a protective treatment of thatch against growth of algae comprising treating at least part of the thatch stem with a composition comprising a silicon compound according to one of formulas (I) - (IV):
(R1O)nSi(R2)3-n (I)
(R2)3Si - O - Si(R2)3 (II)
or
wherein R1 is H, C1-C20 alkyl or C6-C20 aryl;
R2 is C1 - C20 alkyl, C1- C20 alkoxy, C6-C20 aryl or C6-C20 aryloxy;
R3 is H, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
R4 is OH, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
n is 1 - 4, provided that n = 1 if R1 is H;
m is 2 - 100;
o is 3 - 100;
at a temperature between 0 and 200 °C, wherein said method increases the water resistivity of the thatch.
[0010] In case there are more than one R1, R2, R3 and/or R4 groups, these groups are independent of each other. Preferably, m or o are 2-50, more preferably 0-10. For brevity, the silicon compound is further identified in the description as "the compound". The compounds as described above do not comprise amino silanes. Both formula's III and IV refer to two alternatives, IIIa and IIIb, and IVa and IVb, respectively. In a preferred embodiment, the alkyl, alkoxy groups, aryl groups and aryloxy groups may be substituted with one or more halogen atoms, preferably fluorine. Preferably, a compound of formula I has R1 C1-C20 alkyl.
[0011] Advantageously, this method provides thatch that suffers less from the growth of algae when e.g. used on thatched roofs.
[0012] The thatch used herein is preferably based on the type of Phragmites Australis thatch, as is found in e.g. Poland, Hungary, Austria, Turkey and the Netherlands. The term "composition" herein means a combination of materials like the compound with a solvent, and optionally surfactants, etc., a combination of gasses like the compound in a gaseous state together with e.g. steam, but herein "composition" may also mean the compound itself in liquid or gaseous state. This means that the composition, either as fluid or as gas, comprises about 0.01 wt.% to 100 wt.% of the compound, based on the total weight of the composition, and further, when the composition does not comprise 100 wt.% of the compound, e.g. a solvent (when fluid composition) or another gas (like steam) (when gaseous composition). Herein, thatch (stems) also comprises reed (stems) suitable for use on thatched roofs.
[0013] In a preferred embodiment, the composition is a fluid composition. According to a further embodiment of the invention, the method comprises a) treating at least part of the stem, preferably by dipping at least part of the stem, in the composition. As mentioned above, dipping can be performed in several ways. At least part of the stem, preferably about 5-90 cm, calculated from the bottom of the stem (which is dipped in the composition), more preferably about 10-50 cm, e.g. 20-40 cm of the stem is dipped in the composition. This can be performed at elevated temperatures, e.g. between about 30 and 200°C, preferably 30-150°C, and more preferably between about 30-100°C. Even more preferably, the temperature is not lower than about 5°C and not higher than about 80°C.
[0014] In yet a further embodiment, dipping is provided in a vessel, like an autoclave. Typical temperatures are between about 30-125°C, preferably between about 30-100°C. Even more preferably, the temperature is not lower than about 5°C and not higher than about 80°C. The pressure in such a vessel can be between about 1.2 and 5 bar. A treatment of about 1-15, preferably between about 1.5-5 minutes may usually be enough to provide the advantages of the invention.
[0015] According to another embodiment of the invention, the method comprises b) treating at least part of the stem, preferably by spraying at least part of the stem with the composition. This spraying can be performed to stems of thatch before preparing the thatched roof, but advantageously, the method of this embodiment can also be provided to ready thatched roofs. Spraying can be performed by means known to the person skilled in the art like providing a jet of liquid comprising the composition to at least part of the thatch stem or at least part of the roof, respectively, providing a kind of shower to at least part of the thatch stem or at least part of the roof, respectively, providing a haze of the liquid comprising the composition to at least part of the thatch stem or at least part of the roof, respectively, etc.
[0016] In a variation on this embodiment, the composition is provided to at least part of the roof by a steam treatment, wherein steam is led through the composition or wherein the composition is heated, such that steam comprising the compound can be provided to the thatched roof.
[0017] Contacting the thatch stems or thatched roof by spraying can be performed at elevated temperatures, e.g. between about 30 and 200°C, preferably 30-150°C, and more preferably between about 30-100°C. Even more preferably, the temperature is not lower than about 5°C and not higher than about 80°C. As mentioned above, heating can e.g. be performed by providing steam, but spraying at elevated temperatures can also be performed in a means like a vessel, container, etc, containing sprayers or sprinklers that are able to spray thatch or bunches of thatch, and wherein either the fluid or the vessel etc., or both are heated to the desired temperature. During spraying, the thatch or bunches of thatch may be rotated, e.g. to provide the liquid comprising the compound to the complete stem (or bunch). Herein, bunches are also indicated as bundles.
[0018] In yet another embodiment, a method is provided wherein the composition is a gaseous composition. In a preferred embodiment of the invention, the method comprises c) providing a gas comprising the composition to at least part of the stem. As mentioned above, this can be achieved by bringing the composition in the gas phase, bringing a fluid comprising the composition in the gas phase or by providing steam to the composition, thereby carrying the compound to at least part of the stem of thatch or bringing the composition in the gas phase. Herein, gas may also mean a vapour. For example, steam may be a carrier of a vapour of the compound.
[0019] This can be performed in a vessel, like an autoclave, etc. The method of providing the gas can be performed at elevated temperatures, e.g. between about 30 and 200°C, preferably 30-150°C, and more preferably between about 30-100°C. Even more preferably, the temperature is not lower than about 5°C and not higher than about 80°C. The pressure can be between about 1.2 and 5 bar. A treatment of about 1-15 minutes, preferably between about 1.5-10 minutes is usually enough to provide the advantages of the invention.
[0020] Referring to the embodiments above, the temperature the thatch or bunch of thatch experiences is below 200°C, preferably lower. However, when water vapour is present, preferably a saturated water vapour, thatch can experience a temperatures between about 80-200°C, preferably between about 80 and 150°C, without substantial damage, when the treatment last for only about 1-15 minutes.
[0021] In another embodiment, using a dipping fluid at a temperature of about 80-100°C, especially an aqueous fluid comprising the composition, provides the advantage that the thatch or reed also dries relatively quickly. The same applies for treating the thatch according to method b) or c) with a sprinkling liquid or a vapour, respectively, preferably a sprinkling liquid or a vapour, respectively further comprising water or water vapour, respectively. Due to the presence of water or water vapour, respectively, the thatch can experience a temperatures between about 80-200°C, preferably between about 80 and 150°C.
[0022] According to yet a further embodiment, after having treated the thatch by dipping with the composition, the thatch is treated by providing a gaseous composition comprising the compound (i.e. a combination of embodiment a) and c)).
[0023] According to yet a further embodiment, there is provided a method according to the invention, wherein after treating the thatch with the composition (either method a, b or c, or combinations thereof), the thatch is treated with steam. This method provides additional advantages in that the compound is better distributed in and over the thatch and/or in that bacteria and algae are eliminated. In yet a specific embodiment, the thatch stem is first dipped in the liquid comprising the composition, e.g. by a dipping of about 2-10 cm, and then steam is provided to the end of the stem that was dipped in the liquid and steam is provided along the longitudinal axis of the stem, thereby distribution the compound (composition) and/or the liquid comprising the compound (composition) through the whole stem. In an embodiment, this steam treatment is performed in an autoclave.
[0024] Due to the treatment of the thatch, the contact angle of water on the surface of the thatch stem is enlarged. For a given droplet on a solid surface, the contact angle is a measurement of the angle formed between the surface of a solid and the line tangent to the droplet radius from the point of contact with the solid. The contact angle is related to the surface tension by the Young's equation through which the behaviour of specific liquid-solid interactions can be calculated. A contact angle of zero results in wetting, while an angle between 0 and 90 results in spreading of the drop. Contact angles can be measured with e.g. optical methods known to the person skilled in the art. With the method of the invention, the contact angle is enlarged with at least 10°, e.g. about 10-50°, with respect to untreated thatch.
[0025] The method of the invention can further be performed under a pressure of 0.2-10 bar, preferably 0.5-5 bar, more preferably between about 1.2 and 5 bar. This especially applies to the method wherein an autoclave is used, either for dipping (a), for treating with a gas (c) or for a combination thereof (simultaneously or successively). In another preferred embodiment, there is provided a method according to the invention, further comprising further providing a fire retardant to at least part of the thatch stem. This can be a method wherein the composition further comprises a fire retardant. Fire retardants are known to the person skilled in the art.
[0026] Preferably, the composition (either for use as dipping fluid, or as spraying fluid, or a fluid to provide a gas by heating or by providing steam) is an aqueous composition. Hence, in an embodiment, the composition comprises 0.1 wt. % or more of the compound, and further 0-99.9 wt.% of a solvent, wherein at least part of the solvent, preferably 0-99.9 wt.% of the total composition is water. Preferably, at least 90 wt.% of the total composition, more preferably at least 95 wt.% of the total composition comprises water, the rest comprising the compound (preferably between about 0.1 and 5 wt. % of the total composition) and additives. Part of the solvent may be replaced by additives like surfactants, stabilizers, etc.
[0027] In a preferred embodiment, the viscosity of the compound, as measured according to DIN 53015, at 20°, is between about 0.5-1200 mPa.s, preferably between about 0.9 and 1000 mPa.s, more preferably below about 800 mPa.s. The person skilled in the art will choose the compound or its oligomer, preferably in these viscosity ranges, depending upon which method is to be applied (a, b or c). The composition may further comprise a catalyst for polymerisation. This catalyst can be added to the composition shortly before use, such that the composition can polymerize on the thatch surface.
[0028] As a result of the treatments as mentioned in the above-described embodiments (a, b c and combinations thereof), the composition modifies the surface of the thatch. For example, this modification may mean a protective coating whereby OH-groups on the thatch surface are modified to OR-groups, wherein R means a residue, which is derived from molecules that are present in the fluid. The person skilled in the art will choose those fluids and those R-providing molecules in the fluid (i.e. chose those 'surface modifiers'), that the thatch is not chemically destroyed. Surprisingly, by the method of the invention, as described herein in the different embodiments, the growth of algae is diminished or eliminated.
[0029] The compound for treating the thatch stem may be selected from an alkoxy silane, a silanol, an alkoxy silanol, a siloxane, an alkoxy siloxane and an oligomer of one or more of the before mentioned. Preferably, the compound is a compound of one of formulas I-IV and preferably comprises one or more halogen atoms. More preferably, the compound comprises one or more fluor atoms.
[0030] The compounds that can be used in the composition of the invention, can be either in solution, emulsion, as pure liquid, as gas composition or as pure gas. The compounds are e.g. 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl -trimethoxysilane, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl-trichlorosilane, 3,3,4,4,5,5,6,6,7,7,8,8,8-tri-decafluorooctyltriethoxysilane, 3,3,4,4,-5,5,6, 6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl-triethoxysilane, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,-10,10,10-heptadecafluorodecyltrichlorosilane, 3,3,-4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-decyltrimethoxysilane, 3,3,4,4,5,5,6,6,6-nonafluoro-hexyltriethoxysilane, 3,3,4,4,5,5,6,6,6-nonafluorohexyltrimethoxysilane, 3,3,4,4,5,5,6,6,6-nonafluoro-hexyltrichlorosilane, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10,11,11,12,12,12-heneicosafluorododecyltri-ethoxysilane, 3,3,3-tri-fluoropropyltrichlorosilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane or 3-(1,1,2,2-tetra-fluoroethoxy)propyltrimethoxysilane or 3-(1,1,2,2-tetrafluoroethoxy)propyltrichlorosilane, or, methyltrimethoxysilane, methyltriethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, octyltriethoxysilane, isooctyltrimethoxysilane, hexedecyltrimethoxysilane, and cyclohexyltrimethoxysilane, and cyclohexyltriethoxysilane, and cyclohexenylethyl-triethoxysilane, cyclooctenyltrimethoxysilane, and also tetraethoxysilane and also vinyltrimethoxysilane, vinyl triethoxysilane, vinyltris(methoxyethoxy)silane or 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane and trifluoropropyltrimethoxysilane, trifluoropropylmethyldimethoxysilane.
[0031] Referring to the dipping method, in a most preferred embodiment the dipping is applied at temperatures below 80 °C, e.g. 0-60°C. Performing the method of the invention at higher temperatures may damage the thatch. In a further embodiment, dipping is applied at temperatures between 10 and 50 °C, e.g. at room temperature. The person skilled in the art will choose a temperature of the fluid, suitable to dip the thatch in the fluid.
[0032] The dipping may be a complete dipping of the thatch stem, but one may also dip part of the thatch stem, e.g. enough to provide the water resistivity of that part of the thatch on thatched roofs that is exposed to rainfall. This may e.g. mean a dipping of about 5-90 cm of the thatch stem, e.g. 20-40 cm.
[0033] Other methods, known in the art to protect thatched roofs, like e.g. the one described in GB 2105382, only provide a coating on the thatch stems of the thatched roof (and to a certain extend also in between the stems of the thatched roof). However, the method of the invention advantageously provides a treatment of substantially all thatch stems that may later be used in a thatched roof or another application. Another advantage is that the use of thatch treated against algae according to the method of the invention, allows thatched roofs to be treated less frequently than thatched roofs with untreated thatch or treated with known techniques. For example, with known techniques thatched roofs in countries like UK or the Netherlands have to be treated each year or every two years, whereas thatched roofs with thatch according to the invention do not need to be treated with an additional treatment within 5 years or even for its whole life time (about 30-60 years).
[0034] Thatch comprises an external surface and an internal surface. With internal surface is not only meant the surface of the larger internal channel that is present, but especially the surface of the numerous smaller pores that are present in the stem wall, with pore diameters varying from about a few hundred µm's to about 0.1 µm or less. In the method of the invention, it is believed that the composition modifies the internal surface of the thatch. In this way, thatch is protected through and through, thereby providing a much better protection of thatch against algae than with methods known in the art. This may be due to a reduced capillary effect or activity of the pores of the thatch.
[0035] Now, when thatch is used e.g. on thatched roofs, rain will not, or will not easily, penetrate the pores of the thatch. Foil processes, growth of algae etc. in and on the thatch of the roof is surprisingly prevented or reduced. Further, the protection of the thatch is not easily reduced due to a washing out by rain or natural fragmentation of the thatch, since water does substantially not penetrate into the small pores of the thatch.
[0036] In an embodiment of the invention, the invention is directed to a method wherein the composition comprises at least one selected from silane, silanol and siloxane and oligomers and polymers of silane, silanol and siloxane, and further optionally a suitable carrier. Suitable carriers may be necessary, e.g. to dissolve the silane, silanol, siloxane, or polysiloxane or to emulsify the mixture. Suitable carriers may therefore be solvents or emulsifiers, etc. Also oligomers or polymers of silane or siloxane may be used. Such oligomers or polymers may be used as starting materials, but part of the oligomerisation or polymerisation may also be obtained during the treatment of the invention and/or during the subsequent drying. The invention is also directed to a method wherein the silane, silanol or siloxane comprises a fluor modified silane, silanol or siloxane (i.e. wherein silane, silanol, siloxane, oligomers and polymers of silane, silanol and siloxane are fluor modified). Halogen modified components may advantageously be used, since they may be water soluble, but provide a hydrofobic surface (especially internal surface) of the thatch.
[0037] Good treatment results may be obtained with fluids comprising alkyl trialkoxy silanes, such as trimethoxy propylsilane, oligosiloxanes comprising e.g. 3-50 monomers, polysiloxanes (comprising more than about 50 monomers), halogen modified silanes, siloxanes, and polysiloxanes, and mixtures of two or more of these.
[0038] An advantage of using a fluid comprising at least one selected from silane, siloxane and polysiloxane is that such fluids do not change the colour of the thatch. Further, advantageously a method is provided wherein the fluid modifies the internal surface, but wherein the pores are not closed (the smaller pores within the stem wall). Hence, this method allows a breathing of the thatch (thatched roof) and prevents an accumulation of water which may be the case for thatched roofs treated with a coating or lacquer (e.g. when a method according GB 2105382 is used). In other words, thatch treated according to the method of the invention has an increased water resistivity (reduced capillary force for water) but is nevertheless permeable for water vapour.
[0039] In one embodiment, the invention is directed to a method, wherein the fluid comprises 0.1 wt. % or more siloxane and a solvent for siloxane (e.g. iso paraffin), and in a further embodiment, the invention is directed to a method, wherein the fluid comprises 0.1 wt. % or more silane and a solvent for silane (e.g. acetone). In a further embodiment, the invention is directed to a method, wherein the fluid comprises 0.1 wt. % or more of a oligomer or polymer of siloxane or silane. Hence, the invention is also directed to a method wherein the fluid comprises 0.1 wt. % or more siloxane and/or silane, and further a solvent (suitable for siloxane, silane or both components).
[0040] Also mixtures of two or more components selected from silane, silanol, siloxane and oligomers and polymers of siloxane and silane may be chosen, as well as e.g. halogen modifications of these components (e.g. fluor modified). Silane, silanol, siloxane and oligomers and polymers of silane, silanol and siloxane, etc. may also be used undiluted, provided they are liquid at the dipping temperature.
[0041] Thatch has a hydrophilic surface. After the treatment of the invention, the thatch is dried, e.g. by a drying at room temperature. After this drying the surface of the thatch is hydrophobic. Due to the hydrophilic surface before, and probably also during part of the treatment, it is possible to add to the fluid also hydrophilic substances or additives, like e.g. fire retardants. Fire retardants are usually based on urea, borates, phosphates, bromides, etc. and are usually soluble in water. This also applies to most of the fire retardants that are used for protection of thatched roofs.
[0042] Fire retardants are generally sprayed on thatched roofs. The disadvantage of such fire retardants is that they may be easily washed away due to rainfall and a disadvantage of only spraying on the roofs is that only part of the thatch of the thatched roof is protected. However, the invention provides advantageously a solution to this problem by providing a method according to the invention wherein the fluid further comprises a fire retardant. In this way, the method of the invention affords thatch that has a hydrophobic surface as well as a surface impregnated or coated with a fire retardant.
[0043] In contrast to state of the art methods for protection of thatched roofs against fire, wherein only the thatch at the surface of the thatched roof is treated, all thatch stems that may be used for such thatched roofs have a kind of protective coating with a fire retardant, thereby substantially diminishing the danger of fire or a fast progress of fire. Next to that, the method of the invention provides a further advantage since the fire retardants are better attached to the thatch surface, especially the internal surface, due to the protective treatment with a fluid that increases the water resistivity. Without being bound to any theory, this may be due to a partly or completely shielding, encapsulation or coating of the fire retardants by the surface modifiers. Also other additives may be added to the fluid, like e.g. fungicides, algicides, etc.
[0044] According to yet a further aspect of the invention, there is provided a thatch stem (or bunch of thatch stems (reed stems)) comprising a water-resistant internal surface obtainable by applying the method according to one of the preceding claims. This thatch stem has a capillary power for water of 0-1 cm, after dipping at room temperature for 1 minute in an ink solution (preferably indian ink solution with 1-5 gram ink per liter water). The thatch is kept in this fluid for 1 minute and then removed from the fluid. The thatch is cut, such that the stem wall can visually be inspected. The ink has penetrated the thatch stem wall to a certain height cp (or length) and this length cp is measured (capillary power).
[0045] Further, the thatch according to the invention is characterised by comprising the compound (as used in the method of the invention) on its surface and in its pores. For example, the thatch contains about 0.0001-5 wt.%, preferably 0.001-1 wt.% of the compound. Further, thatch treated according to the method of the invention shows a reduction in water take-up of more than 20 % with respect to the untreated thatch, preferably at least a 50 %. Preferably, the water take-up of thatch treated according to the invention is less than 10 wt.% of the total thatch stem, preferably less than about 5 wt.%, more preferably less than 2 wt.%, and even more preferably below 0.5 wt.%, and even most preferably between 0.02 and 0.05 wt.% of the total weight of the thatch stem. Hereby, water take-up is measured as the difference (wt.%) of the weight of the thatch before and after immersing the thatch for 1 hour in water at room temperature, followed by a drying at room temperature during 1 hour.
[0046] Further, according to another aspect of the invention, there is provided the use of a composition comprising a silicon compound according to one of formulas (I) - (IV):
(R1O)nSi(R2)3-n (I)
(R2)3Si - O - Si(R2)3 (II)
or
wherein R1 is H, C1-C20 alkyl or C6-C20 aryl;
R2 is C1 - C20 alkyl, C1 - C20 alkoxy, C6-C20 aryl or C6-C20 aryloxy;
R3 is H, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
R4 is OH, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
n is 1 - 4, provided that n = 1 if R1 is H;
m is 2 - 100;
o is 3-100;
for providing a protective treatment of thatch, especially for providing protection against algae or the growth of algae.
[0047] In another embodiment, the method of the invention comprises a treatment of the thatch with one or more selected from fungicides, algicides and fire retardants, followed by a protective treatment of thatch against growth of algae comprising dipping the thatch in a fluid that increases the water resistivity of the thatch (a) or the other treatment methods (b, c).
[0048] In a further embodiment, the method of the invention further comprises a vacuum treatment. The treatment of the invention may be followed by such a vacuum treatment in order to improve the penetration of the fluid into the pores etc. and thereby to improve the surface modification of the internal surface by the surface modifiers. In another embodiment, the method of the invention further comprises a pressure treatment. Vacuum and pressure treatments may also be used both, e.g. first a vacuum treatment, followed by a pressure treatment. Hence, the invention is also directed to a method further comprising a vacuum treatment and/or a pressure treatment
[0049] In a further aspect of the invention, the invention is directed to thatch comprising a water-resistant internal surface obtainable by applying the method according to one of the preceding claims with at least one selected from silane, silanol, siloxane and oligomers and polymers of silane, silanol, and siloxane (and further optionally a suitable carrier). Such thatch may have a capillary power for water of less than 1 cm. This can be measured by (vertically) dipping the thatch in water wherein a dye (e.g. ink) is dissolved for a certain amount of time (e.g. a minute) and then investigating the height the ink has penetrated the stem wall of the thatch. This height or penetration length is indicated as capillary power. Thatch treated according to the method of the invention will have a capillary power of less than 1 cm, e.g. 0.5 cm, whereas thatch treated in the same way, but with a algicide known in the art, may have a capillary power of 4 or more cm. Untreated thatch may have a capillary power of about 10 cm or more.
[0050] In another aspect of the invention, the invention is also directed to the use of a comprising the compound as described above for a protective treatment of thatch against growth of algae. Such use also increases the water resistivity of the thatch.
[0051] Herein, thatch comprises thatch for thatched roofs, e.g. stems of 10-200 cm, preferably about 100-200 cm, and also comprises individual thatch stems that can be used to make thatched roofs. An example of thatch suitable for application in the invention is Schermer-Beemster thatch (or reed), but also other thatch known to the person skilled in the art can be applied.
Figure 1 schematically describes a bunch 2 of thatch stems 1 with a length 1, being dipped in a liquid 3, contained in a vessel. The dip height dp is calculated from the bottom 4 of the bunch 2 to the surface of liquid 3.
Figures 2a and 2b schematically show the capillary power cp after, i.e. the way a liquid travels in the thatch stem 1 after being dipped for 1 minute in liquid (for this test, the same set up as schematically shown in figure 1 can be used). 2a shows untreated thatch 1, figure 2b shows treated thatch stem 1. The capillary power cp is the height the liquid penetrated the thatch stem wall. Figure 2c schematically shows part of a thatch stem 1, with surface 8 and a droplet 6, having a contact angle θ.
Figure 3 schematically shows an autoclave 10, with liquid 3 and an optional sensor 11, e.g. for pressure, temperature, or a number of sensors for pressure and temperature, etc.
Figure 4 schematically shows a steam treatment, with a means 20 for generating steam through an opening 25.
Examples
Example 1: influence of treatment on thatch and their performance
[0052] Thatch of Noord-Holland (Schermer-Beemster), standard quality, with stems of 40 cm length 1 (see also figure 1) (obtained by selecting a part of this length from the middle of a 2 m thatch stem) is bundled to a bundle 2 with a diameter of about 10 cm of thatch. The diameter of the thatch is typically about 2-5 mm.
The bundle 2 of thatch 1 was treated with the following fluids 3:
1. acetic anhydride (100 %)
2. DMDHEU (dimethylol dihydroxy ethyelene urea), 5 % in water, Clariant
3. Bethoguard 3-(benzo[b]thien-2-yl)-5,6-dihydro-1,4,2-oxathiazine-4-oxide, 3.1 % in water, from Janssen Pharmaceutica
4. an (oligomer) siloxane blend, comprising about 6-7 wt. % dissolved in isoparaffin
5. Arquad (didecyldimethyl-ammonium chloride) 1 % in water, from Akzo Nobel
6. Water (blank)
[0053] The bundle 2 of the thatch 1 was treated according to the following two methods (all experiments were done twice):
A:
- dipping the bundle 2 in the fluid 3 at 120-125 °C
- 30 minutes vacuum
- 60 minutes 8 bar
- remove from fluid
- 1 week drying in air at about 25-30 °C
B:
Same method as A, but dipping at about 20 °C.
Results example 1
[0054] The thatch 1 after method A was very brittle and useless for application in thatched roofs. Thatch treated according to method B was not brittle and could be used for application in thatched roofs. However, only the thatch treated according to the invention (i.e. with a fluid that increases the water resistivity) provided a thatched roof with good properties (see also examples 2 and 3).
Example 2: capillary power
[0055] Thatch treated according to method B with fluids 3-5 were measured with respect to their capillary power. This experiment is performed at room temperature (20°C). The experiment was performed in the following way (see also figures 1 and 2 (I and II)):
[0056] Ink was added to a can with water, such that a coloured aqueous solution is obtained. Thatch 1 in the bunch of thatch 2 is dipped in this solution 3 in a vertical way (perpendicular to the surface of the fluid), such that the thatch is with 5 cm (calculated from the 'bottom' 4 of the thatch) in the fluid (dipping height dp). The thatch is kept in this fluid for 1 minute and then removed from the fluid. The thatch is cut, such that the stem wall can visually be inspected. The ink has penetrated the thatch stem to a certain height cp (or length) and this length cp is measured (capillary power). This height of the ink in stem wall is shown in figure 2 (schematically the cut stem is shown).
Results example 2
[0059] Though the capillary power cp may be estimated in different ways, it is clear that the thatch treated according to the invention provides excellent water resistivity results, thereby providing thatch with a diminished probability of growth of algae.
Example 3: humidity in a thatched roof and algae growth
[0060] Small pilot thatched roofs were made by the bundles 2 of thatch treated according to the method of the invention and with thatch that was untreated or treated with 3-5.
[0061] Additionally, thatch treated with a lacquer (nr. 7: e.g. white spirit/solvent-based drying oils (e.g. linseed/polyunsaturated drying oils)) or with a commercially available vinylacrylate copolymer (nr. 8). The relative humidity was tested according to known techniques with a probe a few centimetres under the surface of the bundle (thus within the bundle of thatch) after rainfall.
Results example 3
[0062] The relative humidity of untreated thatch in the thatched roof was about 90-100%, measured directly after rainfall. Thatch treated according to the invention provided a thatched roof with a relative humidity after rainfall equal to the relative humidity of the surrounding atmosphere (e.g. 60%). Thatch treated with fluids 3 and 5 showed a relative humidity between the relative humidity of the atmosphere and the relative humidity of untreated thatch. Thatch treated with a lacquer (nr. 7) or with the copolymer (nr. 8) provided thatched roofs with also a low relative humidity. However, the humidity increases after some months due to an accumulation under the thatch that is treated with the lacquer. This lacquer layer provides a closed surface, such that water vapour cannot disappear.
[0063] Further, after a 6 months of testing, all thatched roofs change colour and algae growth was observed (also on thatched roofs based on thatch treated with nr. 7 or nr. 8), except for the thatched roofs based on thatch treated according to the invention. These roofs showed no algae growth on the thatch.
Example 4: method without pressure or vacuum
[0064] Thatch 1 of Noord-Holland (Schermer-Beemster), standard quality with stems of 40 cm I (obtained by selecting a part of this length from the middle of a 2 m thatch stem) is bundled to a bundle 2 with a diameter of about 10 cm of thatch.
[0065] The bundle 2 of thatch was treated with the following fluids:
9. oligomer siloxane (low molecular oligomerised alkylalkoxysilane), an oligomerised silane with reactive OR groups. (It can react with OH groups of the cellulosic surface of the thatch and/or can also polymerise to polysiloxane. During and after drying, polymerisation may also take place, e.g. as a result of a pH change.)
9.a. The oligomer siloxane is solved in isoparaffine (7%). Next to this fluid, also fluids were used which were diluted with acetone:
9.b. 2x diluted
9.c. 5x diluted, and
9.d. 10x diluted.
10. Alkylalkoxysilane (trimethoxy propyl silane)
10.a. 100% fluid. Next to this fluid, also fluids were used which were diluted with acetone
10.b. 2x diluted,
10.c. 10x diluted and 20x diluted
11. Fluor modified organofunctional polysiloxane (Protectosil SC, Degussa).
11.a. 50% aqueous solution. Next to this solution, more diluted solutions as fluids 3 were used, which were further diluted with water
11.b. 2x diluted,
11.c. 10x diluted and
11.d. 20x diluted.
[0066] Thatch stems 1 were treated with these fluids according to method C:
C:
- dipping the bundle 2 in the fluid 3 at about 20 °C
- 1 minute
- remove from fluid 3
- 1 day drying in air at about 25-30 °C
Results example 4
[0068] All thatch treated according to method C with fluids 9a-d, 10a-c and 11a-d had a capillary power cp smaller than 1 cm, even the most diluted fluids.
Example 5
[0069] Thatch of Noord-Holland (Schermer-Beemster), standard quality with stems of 15 cm 1 is bundled to a bundle 2 with a diameter of about 10 cm of thatch and used for dipping with another series of fluids 3, amongst others the silane siloxane blend of example 1:
12. an (oligomer) siloxane blend, comprising about 6-7 wt. % dissolved in isoparaffin
12.a. 6-7% fluid
12.b. same as 11a, but 10x diluted with white spirit
12.c. white spirit (blank)
[0070] Thatch were treated with these fluids 3 according to method D (all experiments were performed 3 times):
- dipping the bundle 2 in the fluid 3 at about 20 °C
- 2 minutes
- remove from fluid
- 1 week drying in air at about room temperature
Results example 5
[0072] The following results were obtained for the capillary power cp:
12.a. 0 cm
12.b. 0 cm
12.c. about 10 cm
[0073] This experiment also shows that even strong diluted silane/siloxane fluids can be used to obtain the advantages of the invention.
Example 6: Autoclave treatment
[0074]
A
1. A bunch 2 of thatch (10 stems with a length 1 of about 20 cm) were dipped in a 0.3 wt.% fluor (poly)silane solution (Protectosil SC, Degussa, Lots 2930207214-2L11-BS and 2930405273) (comprising modified organofunctional polysiloxane) with a dip height dh of 3 cm (i.e. substantially vertically dipping the thatch 3 cm in the liquid 3, calculated from the bottom 4 of the stem) for three minutes.
2. The bunch 2 of thatch was placed in an autoclave 10 (Webeco A25, 2.7 kW, 22 1), partially filled with water (liquid 3). The read is arranged above the water surface, such that there is no physical contact with the liquid water 3 in the autoclave 10. The autoclave is heated for 15 minutes at temperature of 121 °C at 1.2 bar (e.g. measured by sensor(s) 11. e.g., by selecting a certain pressure value, the required temperature is reached).
3. Thereafter, no heat is transferred to the contents of the autoclave 10 and temperature and pressure reduce.
4. After a few minutes autoclave 10 was opened.
B
This experiment is the same as A, with the exception that autoclave 10 was opened
(step 4) after a few hours, such that the temperature could slowly be reduced during
this time.
C
This experiment is the same as A, with the exceptions that thatch 1 was not dipped
in the solution (step 1) and instead of water in the autoclave (step 2), the 0.3 wt.%
fluor polysilane solution as liquid 3 was used (no contact of the liquid in the autoclave
with the thatch).
D
This experiment describes the same autoclave treatment as described in A, but from
thatch that was not treated with a compound according to the invention. The untreated
bunch 1 of thatch was placed in an autoclave 10 (as above), partially filled with
water (liquid 3). The read is arranged above the water surface, such that there is
no physical contact with the liquid water in the autoclave. The autoclave 10 is heated
for 15 minutes at temperature of 121°C at 1.2 bar. Thereafter, no heat is transferred
to the contents of the autoclave 10 and temperature and pressure reduces. After a
few minutes the autoclave 10 is opened.
A-D
After the treatment of the bunches obtained in A-D, the bunches were dried during
about 30 minutes at room temperature, subsequently completely immersed in water during
1.5 h and dried again.
Results example 6
[0075] The capillary power cp as described above was determined by vertically dipping the bunch 2 of thatch 1 in an ink solution (liquid 3) for, in this case 3 minutes, with a dip height dh of 1 cm. This was done before the complete treatments (reference value) and after the treatments. For treatments A, B and C, the capillary power cp reduced with 50% or more, whereas the treatment with only water (D) did not provide a reduction. Experiments with a dip time of 1 minute do not provide substantially different results.
[0076] Further, the contact angle was measured by digital camera (with a focussing lense). For thatch treated according to A, B and C, the contact angle 0 (see figure 2c) of drop 6 on thatch 1 increased with >10°, whereas treatment D did not result in an increase of the contact angle. Figure 2c schematically depicts a part of a surface 8 of a thatch stem 1, with a droplet (of water) 6. The contact 0 is indicated in the figure. Contact angle 0 of untreated thatch is less than about 90°, typically about 10-50°. Water on thatch treated according to the invention has a contact angle of at least 55°, but at least 10°, preferably 10-50° larger than the same thatch before the treatment according to the invention. The contact angle before treatment depends upon the kind of thatch used.
Example 7: Steam treatment
[0077]
A
1. A bunch 2 of thatch (10 stems with a length 1 of about 20 cm) were dipped in a 0.3 wt.% fluor polysilane solution (Protectosil SC, Degussa) with a dip height dh of 3 cm (i.e. substantially vertically dipping the thatch 3 cm in the liquid 3, calculated from the bottom 4 of the stem 1) for three minutes.
2. Thereafter, steam was provided to the bunch of thatch. The steam was directed to the dipped part of the thatch (4), in the longitudinal direction, as indicated by the arrow in figure 4, the steam being provided by a means 20 like a vessel providing steam at a temperature of about 100°C - 150°C through an opening 25 for about 1 minute. The distance between opening 25 and bunch 2 of thatch can be chosen such, that the temperature the thatch or reed experiences is about 50-80°C.
3. Thereafter, the bunch 2 of thatch is dried at room temperature (in air).
B
This treatment is the same as treatment A, with the exception that instead of dipping
in a fluor polysilane solution (step 1), only step 2 and 3 were performed, and instead
of a steam in step 2, the fluor polysilane solution was used in vessel 20, which was
heated to a temperature between 125 and 150°C.
C
This is the same treatment as B, but with the exception that instead of the fluor
polysilane solution used in step 2 (note, there is no step 1 in treatment B (and C))
a isobutyltriethoxysilane (100 %, Cugla) in means 20 for providing "steam". In this
treatment, no steam is provided, but gaseous isobutyltriethoxysilane is provided,
by heating liquid 3 (isobutyltriethoxysilane) in vessel 20 to a temperature of 150-200°C.
The temperature the bunch 2 of thatch experiences is between about 50-80°C.
D
This treatment is the same as A, but without the dipping with a liquid comprising
the compound according to the invention as in step 1 of treatment A, i.e. a treatment
with only steam (step 2).
Results example 7:
[0078] The capillary power cp as described above was determined by vertically dipping the bunch 2 of thatch 1 in an ink solution (liquid 3) for 3 minutes with a dip height dh of 1 cm. This was done before (reference value) the complete treatments and after the treatments. For treatments A, B and C, the capillary power cp reduced with 50% or more, whereas the treatment with only water (D) did not provide a reduction. Experiments with a dip time of 1 minute do not provide substantially different results.
[0079] Further, the contact angle was measured by a digital camera (see above). For thatch treated according to A, B and C, the contact angle θ increased with >10 °, whereas treatment D did not result in an increase of the contact angle.
[0080] Especially with respect to treatments B and C (no first dip step 1), a longer "steam" step (step 2) than about 1 minute, e.g. 2-15 minutes, can provide even better results, e.g. in terms of complete treatment of the internal surface of the thatch.
Example 8: pilot thatched roofs
[0081] Small pilot thatched roofs of 0.5 m2 were made using Dutch Schermer-Beemster) thatch.
A
A first roof was provided with a thatched roof of thatch treated with a dipping treatment,
wherein a complete dip of the 40 cm stems in a 0.3 wt.% fluor polysilane solution
(Protectosil SC, Degussa) was performed for 1 minute, followed by a subsequent drying.
B
A second thatched roof was made by providing untreated thatch, but treating this untreated
thatch by spraying the thatched roof 0.3 wt.% fluor polysilane solution (Protectosil
SC, Degussa). This spraying was performed with a low pressure sprayer (other means
are also possible) over the whole surface, until the surface was so wet that the thatched
roof started dripping.
C
Same roof as above, but without any treatment of the thatched roof at all.
A-C
All roofs were wetted with water by 8 sprinklers, provided at the top of the roof,
providing water during about 8 hours and a total volume of water of 60 liters. During
and after sprinkling, the weight of the thatched roof was monitored.
Results example 8
[0082] It appeared that the untreated thatched roof (C) had a water take-up of about 0.7 liter/m2, and the weight increased during the whole period of sprinkling. The roof treated according to treatment A had a water take up of about 0.3 liter/m2. Further it was observed that after about 4 hours of sprinkling with water, there was no increase of weight anymore. The sprayed roof (treatment B) showed a water take-up of about 0.35 liter/m2 and there was no increase of the weight of the thatched roof after about 6-7 hours of sprinkling with water.
[0083] After these experiments, the roofs were arranged outside during 4 months. Thereafter, the roofs were dried inside at room temperature, and were sprinkled with water in the same way as described above. The results on water take-up were identical, which shows that the protection according to the invention is not a temporal effect.
Example 9: steam treatment of thatch
[0084] Referring to figure 4, steam is provided from a vessel 20 through opening 25 to a bunch 2 of thatch stems 1, to the end of thatch that was dipped in the liquid (according to method a). Figure 4, and thereby the method for providing steam after a treatment a), may however also be performed horizontally, or upside down. In the latter embodiment, the compound or whole composition is carried by the steam (and/or by water formed by the steam) from the dipped end through and over the thatch, thereby helped by gravity.
1. A method for a protective treatment of thatch against growth of algae comprising treating
at least part of the thatch stem with a composition comprising a silicon compound
according to one of formulas (I) - (IV):
(R1O)nSi(R2)3-n (I)
(R2)3Si - O - Si(R2)3 (II)
or
wherein R1 is H, C1-C20 alkyl or C6-C20 aryl;
R2 is C1 - C20 alkyl, C1 - C20 alkoxy, C6-C20 aryl or C6-C20 aryloxy;
R3 is H, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
R4 is OH, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
n is 1 - 4, provided that n = 1 if R1 is H;
m is 2-100;
o is 3 - 100;
at a temperature between 0 and 200 °C, wherein said method increases the water resistivity of the thatch.
(R1O)nSi(R2)3-n (I)
(R2)3Si - O - Si(R2)3 (II)
or
wherein R1 is H, C1-C20 alkyl or C6-C20 aryl;
R2 is C1 - C20 alkyl, C1 - C20 alkoxy, C6-C20 aryl or C6-C20 aryloxy;
R3 is H, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
R4 is OH, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
n is 1 - 4, provided that n = 1 if R1 is H;
m is 2-100;
o is 3 - 100;
at a temperature between 0 and 200 °C, wherein said method increases the water resistivity of the thatch.
2. Method according to claim 1, wherein the composition is a fluid composition.
3. Method according to claim 1 or claim 2, comprising a) dipping at least part of the
stem in the composition.
4. Method according to claim 1 or claim 2, comprising b) spraying at least part of the
stem with the composition.
5. Method according to claim 1, wherein the composition is a gaseous composition.
6. Method according to claim 1 or claim 5, comprising c) providing a gas comprising the
composition to at least part of the stem.
7. The method according to any of claims 1-6, wherein the method is performed under a
pressure of 0.2-10 bar.
8. The method according to any of claims 1-7, wherein after treating the thatch with
the composition, the thatch is treated with steam.
9. The method according to any of claims 1-8, wherein the compound with one of formulas
I-IV comprises one or more halogen atoms.
10. The method according to claim 9, wherein the compound comprises one or more fluor
atoms.
11. The method according to any of claims 1-10, comprising further providing a fire retardant
to at least part of the thatch stem.
12. The method according to any of claims 2-4, wherein the composition is an aqueous liquid.
13. The method according to any of claims 2-4 or 12, wherein the composition further comprises
a fire retardant.
14. Method according to any of claims 2-4, 12 or 13, wherein the dipping is applied at
temperatures below 100 °C.
15. Method according to any of claims 2-4, or 12-14, wherein the fluid comprises 0.1 wt.
% or more of the compound, and further 0-99.9 wt.% of a solvent.
16. A thatch stem comprising a water-resistant internal surface obtainable by applying
the method according to one of the preceding claims.
17. The thatch stem according to claim 16, having a capillary power for water of 0-1 cm.
18. Use of a composition comprising a silicon compound according to one of formulas (I)
- (IV):
(R1O)nSi(R2)3-n (I)
(R2)3Si - O - Si(R2)3 (II)
or
wherein R1 is H, C1-C20 alkyl or C6-C20 aryl;
R2 is C1 - C20 alkyl, C1 - C20 alkoxy, C6-C20 aryl or C6-C20 aryloxy;
R3 is H, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
R4 is OH, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
n is 1 - 4, provided that n = 1 if R1 is H;
m is 2 -100;
o is 3 - 100;
for providing a protective treatment of thatch.
(R1O)nSi(R2)3-n (I)
(R2)3Si - O - Si(R2)3 (II)
or
wherein R1 is H, C1-C20 alkyl or C6-C20 aryl;
R2 is C1 - C20 alkyl, C1 - C20 alkoxy, C6-C20 aryl or C6-C20 aryloxy;
R3 is H, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
R4 is OH, C1 - C20 alkyl, C1 - C20 alkoxy; C6-C20 aryl or C6-C20 aryloxy;
n is 1 - 4, provided that n = 1 if R1 is H;
m is 2 -100;
o is 3 - 100;
for providing a protective treatment of thatch.
19. Use according to claim 18, for providing protection against algae or the growth of
algae.