Biodegradable sunscreen paint

Abstract

The present invention relates to a biodegradable coating composition comprising a crosslinked starch and a filler, and optionally a polyol plasticizer, and to an exterior structure, such as a greenhouse, provided with a coating layer obtained by drying said coating composition. The present invention further relates to the removal of the coating layer using a targeted cleaning composition.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention is in the field of exterior coating compositions, particularly greenhouse shading coatings. [Background technology]

[0002] In horticulture, greenhouses are a primary tool for adapting growing conditions for specific plants. Greenhouses can be used to optimize plant growing conditions, for example, to ensure a stable supply of plant-based foods. However, seasonal weather changes affect outside temperature and light conditions, which are also influenced by geographic location. Too much light or heat can have a negative impact on crop growth.

[0003] It is known to apply shading paint to protect crops from excessive light and heat during the spring and summer. Shading paint is applied to greenhouses in the form of an aqueous composition containing some form of pigment and a binder. The binder is often a polymer, such as an acrylic polymer. After application and drying of the composition, a layer of pigment embedded in the polymer binder is formed on the greenhouse, which provides shading. However, to accommodate periods with less light and heat, it is preferable to apply a shading paint that can be degraded or actively removed.

[0004] In self-degrading shading paints, the binder slowly decomposes under the influence of ultraviolet light and water, causing the pigment to wash away from the greenhouse over the course of several months. Thus, the layer of shading paint gradually provides less and less shading, until eventually, there is very little shading paint left on the greenhouse. Typically, the decomposition rate of the shading paint is adjusted to weather conditions so that the shading paint more or less disappears after summer, when shading is no longer needed.

[0005] The second type of shading paint composition is the on / off shading paint, also known as removable shading paint or actively removable shading paint. This type of shading paint is optimized to withstand as many weather conditions as possible. At any time, a grower may decide to remove the shading paint to restore the normal transparency of the greenhouse windows. Removal is accomplished with a specialized cleaner, such as an alkaline-based cleaner.

[0006] Whether the shade coating is self-degrading or removable, the shade coating composition that disappears from the greenhouse will eventually enter the environment around the greenhouse. In the case of self-degrading shade coatings, the buildup of binder in the environment begins with the binder's slow decomposition, and rain washes the binder into the soil and / or surface water around the greenhouse. In the case of on / off shade coatings, detergents cause the binder to quickly solubilize. Because the size of the greenhouse's surface prevents the removal of the paint, the shade coating also ends up in the soil and / or surface water around the greenhouse.

[0007] WO 2018 / 169404 describes an alkali-removable, biodegradable coating comprising a polymeric polyester binder, preferably uncrosslinked, having a molecular weight of 2,000 to 50,000 g / mol and an acid value of 40 to 250 mg KOH / g polymer binder. While the binder is referred to as "biodegradable," it is not actually fully biodegradable, with biodegradability indicated as 23 to 83% (OECD 301F).

[0008] WO 99 / 22588 also describes an alkali-removable protective coating comprising a pigment and a polymeric binder, such as a vinyl or acrylate polymer. The binder has an acid number of 40 to 250 and a weight average molecular weight of 10,000 to 100,000. There is no mention of biodegradability, and the synthetic polymer chains and segments, once removed, are generally not environmentally friendly.

[0009] EP 2361957 describes an alkali-removable protective coating formulation comprising a binder and a pigment, the binder being a polymer produced by anionic polymerization, in particular an acrylate or vinyl polymer having an acid number of 100 to 200 and an average molecular weight of 5000 to 10000. There is no mention of biodegradability, and the polymer chains after removal are generally not environmentally friendly.

[0010] Both CN101914336 and CN102676006 also describe water-based polyacrylate coatings with no report on biodegradability or the environmental impact of the polymer chain fragments after removal.

[0011] In these light-blocking coatings, the polymer binder is a synthetic polymer, which pollutes the environment, at least to some extent, after the light-blocking coating is removed. It would be beneficial to obtain a light-blocking coating composition that does not affect the environment. To achieve this, the light-blocking coating composition must be completely biodegradable, and the remaining fragments of the light-blocking coating must be environmentally friendly. The present invention provides such a light-blocking coating composition.

[0012] EP 2370503 describes a biolatex conjugate for use in compositions for coating paper and cardboard, which provides excellent whiteness and brightness. The biolatex conjugate is included in a paper coating formulation that further includes styrene-butadiene latex ("SB latex"). As is generally known, SB latex is not biodegradable, and therefore the coating compositions herein are not biodegradable.

[0013] CN105368164 describes a biodegradable interior wall coating composition containing vegetable starch. The interior wall coating composition contains borax as a crosslinking agent, which is a CMR (carcinogenic, mutagenic, and / or reproductively toxic) in amounts greater than 0.3% by weight. Therefore, the composition in this document is primarily CMR, and therefore dangerous to apply to the exterior of structures such as greenhouses. [Brief explanation of the drawings]

[0014] [Figure 1] The evolution of the shading performance of the self-degrading paint type over time (Equations 1-4) is shown, represented by the average light transmittance from 400 to 800 nm over time. [Figure 2] The evolution of the light-blocking performance of the on / off type paints over time (Equations 7-10) is shown, represented by the average light transmittance from 400 to 800 nm over time. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention relates to a crosslinked starch and a filler, and optionally urea and / or A biodegradable coating composition and methods for applying and removing the coating composition are provided, which include a polyol plasticizer. The polyol plasticizer can be any known plasticizer containing two or more groups capable of hydrogen bonding, preferably hydroxy groups. Preferably, the polyol plasticizer is sorbitol, glycerol, ethylene glycol, polyethylene glycol, xylitol, glucose, fructose, galactose, mannitol, sucrose, maltitol, or any mixture thereof, and most preferably, sorbitol, glycerol, or ethylene glycol.

[0016] The coating composition of the present invention is intended for outdoor use, for example, as a shade coating on a greenhouse.By using cross-linked starch as a binder, the binder is completely biodegradable and environmentally friendly, while at the same time providing sufficient weather resistance to allow formulation as both a self-degrading coating composition and an on / off coating composition.The weather resistance of the coating of the present disclosure is very similar to that of coatings based on synthetic polymer binders, but offers the additional advantages of biodegradability and low environmental impact.

[0017] In this context, biodegradability is defined as biodegradability determined using method OECD 301, which is a commonly known method for assessing biodegradability, as outlined in more detail in the Examples. Biodegradability is defined as at least 90%, preferably at least 95%, biodegradability as determined using method OECD 301.

[0018] In this context, environmentally friendly is understood to mean that the binder is not only fully biodegradable but also has no further adverse environmental effects, and is therefore not carcinogenic, mutagenic or reproductively toxic (non-CMR).

[0019] Cross-linked starch The coating composition includes a cross-linked starch, which functions as a binder. The cross-linked starch provides the necessary adhesion to form a layer on a flat surface (such as a transparent greenhouse panel) after drying, the layer including the cross-linked starch and a filler. When used as a greenhouse shading paint, the layer provides shading within the greenhouse, resulting in light and / or heat reduction. When used as a shading paint on an opaque exterior wall and / or roof, the layer provides heat reduction.

[0020] The cross-linked starch may be any type of starch, or may be a mixture containing two or more types of starch. The starch may be cereal starch (e.g., rice, wheat, and corn), root starch (e.g., potato and cassava), or legume starch (e.g., mung bean, pea, fava, lentil, and chickpea), but may also be derived from other sources (e.g., acorn, arrowroot, barley, breadfruit, millet, oat, sago, sorghum, sweet potato, rye, taro, chestnut, water chestnut, and yam). Preferred starch types are cereal starches and root starches, especially corn starch and potato starch.

[0021] Starch is isolated from plants as a granular material, which contains amylose and amylopectin. Both amylose and amylopectin are water-soluble polymers of glucose; amylose is essentially a linear chain of hundreds to thousands of glucose moieties, while amylopectin is a branched molecule that can contain up to hundreds of thousands of glucose moieties. The ratio of amylose to amylopectin in a starch granule varies depending on the source of the starch and is commonly known. Generally, normal ("native") starch contains 10-30% amylose and 70-90% amylopectin by weight.

[0022] Also, there are plant varieties from which starches rich in amylose or amylopectin can be isolated, relative to the "natural" ratio between amylose and amylopectin in starch types. Starch types rich in amylose are called "amylose-rich" and starch types rich in amylopectin are called "waxy." Waxy starch is starch with an amylopectin content of at least 90% by weight, preferably at least 95% by weight, and more preferably at least 98% by weight. Amylose-rich starch is starch with an amylose content of at least 30% by weight, preferably at least 40% by weight, and more preferably at least 50% by weight.

[0023] Crosslinked starch in this context may be normal starch, which is defined as a starch type having a "native" ratio of amylose to amylopectin for the starch type in question. However, crosslinked starch may also be an amylose-rich starch or a "waxy" type of starch. In a preferred embodiment, the starch is a crosslinked waxy starch. In another preferred embodiment, the starch is a crosslinked normal starch.

[0024] Crosslinked starch is starch that has undergone a crosslinking reaction, thereby introducing covalent bonds between different segments of the same or different glucose polymers. This leads to a network of starch molecules. Crosslinking has been found to significantly improve weather resistance, so crosslinked starch has sufficient weather resistance to provide a usable coating.

[0025] The type of cross-linking agent is not particularly limited, so long as at least some cross-linking of the starch occurs and the cross-linking does not impart environmentally unfriendly properties. The cross-linked starch is preferably non-CMR, and the cross-linking agent is preferably non-CMR. More preferably, the cross-linked starch is a non-borax cross-linked starch, and the cross-linking agent is preferably not borax.

[0026] The crosslinked starch is preferably sodium trimetaphosphate crosslinked starch, ammonium zirconium carbonate crosslinked starch, copper crosslinked starch, magnesium crosslinked starch, borax crosslinked starch, zirconium crosslinked starch, titanium crosslinked starch (e.g., titanium lactate, titanium malate, titanium citrate, titanium ammonium lactate, polyhydroxy complexes of titanium, titanium triethanolamine, or titanium acetylacetonate crosslinked starch), calcium crosslinked starch, aluminum crosslinked starch (e.g., aluminum lactate or aluminum citrate crosslinked starch), cross-linked starch), boron cross-linked starch, chromium cross-linked starch, iron cross-linked starch, antimony cross-linked starch, glyoxal cross-linked starch, p-benzoquinone cross-linked starch, polycarboxylate cross-linked starch (e.g., citric acid, maleic acid, glutaric acid, succinic acid, phthalic acid, and / or malic acid cross-linked starch), phosphite cross-linked starch, phosphate cross-linked starch, silicate cross-linked starch (e.g., tetraethyl orthosilicate (TEOS)), epichlorohydrin cross-linked starch, periodate cross-linked starch, dialdehyde cross-linked starch, or anhydride cross-linked starch.

[0027] In a preferred embodiment, the crosslinked starch is sodium trimetaphosphate crosslinked starch, ammonium zirconium carbonate crosslinked starch, copper crosslinked starch, magnesium crosslinked starch, zirconium crosslinked starch, titanium crosslinked starch (e.g., titanium lactate, titanium malate, titanium citrate, titanium ammonium lactate, polyhydroxy complexes of titanium, titanium triethanolamine, or titanium acetylacetonate crosslinked starch), calcium crosslinked starch, aluminum crosslinked starch (e.g., Cross-linked starches include, for example, aluminum lactate or aluminum citrate cross-linked starches, boron cross-linked starches, chromium cross-linked starches, iron cross-linked starches, antimony cross-linked starches, p-benzoquinone cross-linked starches, polycarboxylate cross-linked starches (e.g., citric acid, maleic acid, glutaric acid, succinic acid, phthalic acid, and / or malic acid cross-linked starches), phosphite cross-linked starches, phosphate cross-linked starches, silicate cross-linked starches (e.g., tetraethyl orthosilicate (TEOS)), and periodate cross-linked starches.

[0028] Most preferably, the crosslinked starch is sodium trimetaphosphate (STMP) crosslinked starch or ammonium zirconium carbonate (AZC) crosslinked starch.

[0029] The crosslinked starch preferably has a crosslinking ratio, defined as the weight percent of crosslinker relative to the weight of crosslinked starch, of 1-50%, preferably 3-25%, more preferably 5-15%. A highly preferred crosslinking ratio is 3-50%, preferably 5-50%. The crosslinking ratio indicates the degree of crosslinking of the starch and directly affects weather resistance. The higher the degree of crosslinking, the higher the weather resistance.

[0030] Those skilled in the art will understand that the percentage of crosslinking is expressed based on the amount of starting material before the crosslinking reaction, and that to obtain crosslinked starch, the starch and crosslinking agent must also be subjected to reaction conditions (solvent, temperature, etc.) and workup appropriate for the type of crosslinking agent in question. For applicable types of crosslinking agents, appropriate reaction conditions and purification methods for obtaining crosslinked starch are generally known.

[0031] In a preferred embodiment, the cross-linked starch is a gelatinized cross-linked starch. In this context, gelatinized cross-linked starch in an aqueous coating composition provides a network of dissolved but covalently bonded starch molecules. After application to, for example, a greenhouse and subsequent drying, this provides a binder with sufficient adhesive and weather resistance.

[0032] Starch gelatinization is generally known to refer to the process by which starch granules in an aqueous environment dissolve to yield a solution of (individually solubilized) amylose and amylopectin molecules. Starch gelatinization generally requires high energy, such as high temperature and / or pressure.

[0033] In a highly preferred embodiment, the cross-linked starch is a pregelatinized cross-linked starch. Pregelatinized starch is starch that has been subjected to gelatinization, but is then dried, for example by spray drying or flash drying, or other methods known in the art, to obtain the pregelatinized starch. Pregelatinized starch has the advantage that it is easily soluble in water.

[0034] The cross-linked starch in the coating composition is preferably gelatinized. In a more preferred embodiment, the cross-linked starch is a pre-gelatinized starch that is subsequently cross-linked to provide the pre-gelatinized cross-linked starch.

[0035] In a further preferred embodiment, the cross-linked starch is a partially hydrolyzed cross-linked starch ("cross-linked starch hydrolysate"), such as by acid hydrolysis or enzymatic hydrolysis, which is further preferably additionally pregelatinized. Starch hydrolysis, as is generally known, results in shorter chain lengths. In the present coating composition, the application of partially hydrolyzed starch has the advantage of reduced viscosity, which facilitates the incorporation of the starch into the coating composition and, for example, the application of the coating composition to a greenhouse.

[0036] Hydrolyzed starch is defined in this context by its DE ("dextrose equivalent") value, as known in the art. DE indicates the degree to which the starch has been hydrolyzed. Pure glucose has a DE of 100, pure maltose has a DE of 50, and starch has a DE very close to 0. Partially hydrolyzed starch in this context is starch with a DE of 0.1 to 15, preferably 0.1 to 10, more preferably 0.5 to 10, or 1 to 10.

[0037] Generally, the partially hydrolyzed cross-linked starch is a cross-linked starch having a DE of 0.1-15, preferably 0.1-10, more preferably 0.5-10, or 1-10.

[0038] The crosslinked starch may have undergone further starch modifications. For example, the crosslinked starch may be further stabilized by etherification or esterification. Thus, the crosslinked starch of the present invention may also be hydroxyethylated, hydroxypropylated, or succinylated, for example. Furthermore, the crosslinked starch may be oxidized, for example by chlorite oxidation. The crosslinked starch may also be thermally inhibited.

[0039] Filler The biodegradable coating composition further comprises a filler. In this regard, the filler may also be referred to as a pigment. The filler may be, for example, an inorganic pigment such as calcium carbonate, titanium oxide, boehmite, mica, silicates (such as magnesium silicate or aluminum silicate), gypsum, barite, aluminum oxide, magnesium oxide, talc, clay, interference pigments, or any combination thereof.

[0040] For the purpose of shading a greenhouse or other exterior structure, those skilled in the art will understand that different types of fillers can be applied for different purposes and at different concentrations. For example, titanium dioxide has a high reflectivity, so relatively small amounts are needed for shading and heat reduction. Calcium carbonate requires more filler to achieve similar shading, but is less expensive and has the added advantage of becoming slightly translucent when wet. This allows the light intensity within the greenhouse to be adapted to weather conditions. Boehmite is known to provide high light scattering, making it suitable for shading greenhouses with a diffuse coating that can be used for crops that require uniformly high light intensity.

[0041] The type of filler used in the present invention is not particularly limited. The weight ratio of filler to crosslinked starch is preferably in the range of 0.05 to 50, preferably 0.1 to 40, more preferably 0.5 to 30, more preferably 1 to 28.

[0042] Polyol Plasticizer In a more preferred embodiment, the biodegradable coating composition includes a polyol plasticizer, which has the effect of reducing the brittleness of the coating layer, thereby further improving weather resistance.

[0043] The polyol plasticizer can be any known plasticizer containing two or more groups capable of hydrogen bonding, preferably hydroxy groups. Preferably, the polyol plasticizer is sorbitol, glycerol, ethylene glycol, polyethylene glycol, xylitol, glucose, fructose, galactose, mannitol, sucrose, maltitol, urea, or any mixture thereof, and most preferably, sorbitol, glycerol, or ethylene glycol.

[0044] The weight ratio of crosslinked starch to polyol plasticizer, when present, is preferably in the range of 0.2-10, preferably 0.3-8, more preferably 0.4-6.

[0045] Coating Composition The biodegradable coating composition may be a dry coating composition or an aqueous coating composition. Dry coating compositions are preferably free-flowing powders which have the advantage that the weight of the composition is minimized.

[0046] Preferably, however, the coating composition of the present invention is an aqueous coating composition. The aqueous coating composition of the present invention preferably comprises a crosslinked starch as defined elsewhere, a filler, and water. This has the advantage that homogenization of the coating can be carried out in a controlled environment on a large scale.

[0047] More preferably, the aqueous coating composition is a concentrated coating composition that can be diluted at the application site, which has the advantage of minimizing shipping weight while allowing for large scale homogenization in a controlled environment.

[0048] The concentrated aqueous coating composition of the present invention preferably has a dry solids content of 10 to 90 wt. %, more preferably 25 to 70 wt. %, more preferably 40 to 70 wt. %, based on the total weight of the composition.

[0049] The concentrated aqueous coating composition is diluted with, for example, preferably 1 to 20 parts by weight of water, more preferably 1 to 15 parts by weight, more preferably 1 to 10 parts by weight, more preferably 2 to 8 parts by weight, and most preferably 3 to 6 parts by weight, based on the total weight of the concentrated aqueous coating composition, before application.

[0050] Due to this dilution, the dry solids content in the aqueous coating composition to be applied is preferably 1 to 50% by weight, preferably 3 to 35% by weight, more preferably 5 to 20% by weight, based on the total weight of the coating composition.

[0051] Thus, the aqueous coating composition of the present invention may have a dry solids content of 1 to 90 wt. %, preferably 3 to 70 wt. %, more preferably 5 to 65 wt. %, based on the total weight of the composition.

[0052] In a preferred embodiment, the coating composition comprises, expressed as a weight percentage by weight of the dry weight of the composition, 1 to 50%, preferably 1.5 to 30%, more preferably 2.0 to 20% of crosslinked starch.

[0053] Furthermore, the coating composition preferably comprises an amount of filler, expressed as a weight percentage of the dry weight of the composition, of 1 to 97 wt %, preferably 50 to 95 wt %, more preferably 75 to 94 wt %.

[0054] The coating composition may also optionally contain a polyol plasticizer in an amount, expressed as a weight percentage of the dry weight of the composition, of 0.05 to 20.0 wt %, preferably 0.5 to 15 wt %, more preferably 1.0 to 7.0 wt %.

[0055] Furthermore, the coating composition preferably comprises at least one selected from the group consisting of a dispersant, a wetting agent, a leveling agent, an adhesion promoter, a biocide, an antifoaming agent, a flocculating agent, a thickener, a pH modifier, and an antifreeze agent.

[0056] The dispersant may be, for example, a phosphate, acrylate, sulfonate or gluconate.

[0057] When present, the dispersant may be included in the composition in an amount of 0.05 to 2.5% by weight based on the dry weight of the composition.

[0058] The wetting agent may be, for example, a polyurea or a polyether.

[0059] When present, the humectant may be included in the composition in an amount of 0.05 to 2.5 wt. %, preferably 0.1 to 1.5 wt. %, based on the dry weight of the composition.

[0060] The leveling agent may be, for example, a fluorine- or silicone-containing nonionic surfactant, or a sulfosuccinate.

[0061] When present, the leveling agent may be included in the composition in an amount of 0.05 to 1.0 wt %, based on the dry weight of the composition.

[0062] The adhesion promoter can be, for example, a silane-based compound having amine or epoxy functionality, such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-(methylamino)propyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, Y-(2-aminoethyl-3-aminopropyl)triethoxysilane and Y-(2-aminoethyl-3-aminopropyl)methyldimethoxysilane, or a metal-based adhesion promoter.

[0063] When present, the adhesion promoter may be included in the composition in an amount of 0.05 to 4.0 wt %, preferably 0.1 to 1 wt %, based on the dry weight of the composition.

[0064] The biocide may be, for example, 1,2-benzisothiazol-3(2H)-one (BIT), 2-methyl-2H-isothiazol-3-one (MIT), 5-chloro-2-methyl-2H-isothiazol-3-one (CMIT), bromopol, sodium pyrithione, or zinc pyrithione.

[0065] When present, the biocide may comprise from 0.001 to 1.0% by weight of the composition, preferably from 0.002 to 0.5% by weight, based on the dry weight of the composition.

[0066] The antifoaming agent may be, for example, a liquid hydrocarbon, a natural oil, a hydrophobic silica, or a non-ionic surfactant such as a silicone.

[0067] When present, the antifoaming agent may be included in the composition in an amount of 0.1 to 2.0 wt %, preferably 0.25 to 1 wt %, based on the dry weight of the composition.

[0068] The flocculant can be, for example, a solvent capable of dissolving crosslinked starch, such as texanol (isobutyric acid), citrofol, an oleochemical glycol ether, methoxypropylene, acetyl tributyl citrate, or hexanoate.

[0069] When present, the flocculant may be included in the composition in an amount of 0.05 to 5.0 wt %, preferably 0.1 to 1.0 wt %, based on the dry weight of the composition.

[0070] The thickener can be, for example, xanthan gum, cellulose, a cellulose derivative such as hydroxyethyl cellulose (HEC) or microfibrillated cellulose (MFC), a polyurethane-based thickener, an acrylic copolymer, a clay, or a non-crosslinked starch-based thickener.

[0071] When present, the thickener may be included in the composition in an amount of 0.05 to 5.0 wt. %, preferably 0.08 to 1.5 wt. %, based on the dry weight of the composition.

[0072] The pH modifier can be, for example, a common acid or base, including strong and weak bases and strong or weak acids, as commonly known in the art. (Non-limiting) examples are sodium or potassium hydroxide, sodium bicarbonate, ammonia, hydrochloric acid, sulfuric acid, citric acid, and gluconic acid.

[0073] If present, the pH modifier may be included in the composition in an amount effective to achieve the desired pH, as is known in the art. The amount of pH modifier is preferably selected to achieve a final pH of the coating composition of 4 to 12, preferably 5 to 11, and more preferably 6 to 10.

[0074] The amount of the pH modifier is preferably in the range of 0.05 to 10.0% by weight based on the dry weight of the composition.

[0075] The antifreeze may be, for example, urea or glycol.

[0076] When present, the antifreeze agent may be included in the composition in an amount of 0.05 to 5.0% by weight, based on the dry weight of the composition.

[0077] The coating composition of the present invention can be prepared by dispersing the different raw materials in a container under agitation. In a preferred embodiment, the solid raw materials are dispersed in water to prepare an aqueous coating composition, as defined elsewhere.

[0078] Preferably, the stirring during dispersion is adjusted to achieve the desired particle size of the filler. The desired particle size of the filler is, for example, a particle size of up to 100 μm, preferably up to 70 μm. The particle size may be measured, for example, by a Malvern particle size analyzer, as is generally known in the art.

[0079] Thus, the present invention further provides a method for preparing a biodegradable coating composition comprising a crosslinked starch and a filler, and optionally a polyol plasticizer, as defined elsewhere, comprising dispersing the crosslinked starch and the filler, and optionally the polyol plasticizer, in water. Preferably, dispersion is achieved by homogenization in a suitable container, such as a bucket or closable vessel, by methods for homogenization commonly known in the art. In a more preferred embodiment, homogenization is achieved by first homogenizing under high stress, followed by further mixing, until the desired particle size of the filler is achieved.

[0080] The coating compositions of the present invention can be formulated as on / off type coating compositions or as self-degrading type coating compositions, which types can be distinguished primarily by their rate of degradation under the conditions in which they are applied.

[0081] The amount of filler and the amount of cross-linked starch primarily determine whether the formulation is an on / off composition or an autodegrading composition. However, optional additional components of the formulation also affect the degradation of the coating. The degradation of the coating is further affected by external conditions such as weather. For this reason, no "hard" distinction can be made between on / off coatings and autodegrading coatings.

[0082] Those skilled in the art will understand that there is some overlap between the two types of coating compositions. A coating composition that has a higher decomposition rate under the weather conditions in which it is applied can more easily be considered a self-decomposing coating composition. Conversely, a coating composition that has a higher resistance to decomposition can be considered an on / off coating composition. Based on the following formulation examples and general knowledge about the decomposition rate of specific coating formulations, as well as some exemplary routine experiments, those skilled in the art can determine whether a particular coating formulation can be considered an on / off coating composition, a self-decomposing coating composition, or whether, in borderline cases, the assignment of either type is considered ambiguous.

[0083] Self-degrading blackout paint When the coating composition of the present invention is formulated as a self-degrading sunscreen coating, the coating composition contains less than 10% by weight of crosslinked starch, preferably less than 7.2% by weight, preferably less than 5% by weight, preferably less than 4% by weight, but more than 1% by weight, most preferably 1.5 to 7.2% by weight, based on the dry weight of the composition. Such compositions have the advantage that they do not need to be actively removed. They can also be formulated to remain intact for weeks or months, taking into account average weather conditions at the site.

[0084] The concentrated self-decomposing sunscreen coating preferably comprises, as a weight percent of the total composition: 35 to 55% by weight, preferably 40 to 50% by weight, of water, and 35 to 65% by weight, preferably 40 to 60% by weight, more preferably 45 to 55% by weight of a filler, and Contains 0.5 to 7.0% by weight, preferably 1 to 6% by weight, more preferably 1.5 to 5% by weight of crosslinked starch; More preferably, the weight percent of the non-aqueous material in the total composition is: 0.05 to 0.8% by weight, preferably 0.1 to 0.5% by weight, of an antifoaming agent, and / or 0.01 to 0.8% by weight, preferably 0.05 to 0.4% by weight, of a thickener, and / or 0.1 to 1% by weight, preferably 0.2 to 0.8% by weight, of a wetting agent, and / or 0.001 to 1.0% by weight, preferably 0.005 to 0.5% by weight, of a biocide, and / or 0.1 to 5.0% by weight, preferably 0.5 to 3.0% by weight, of a plasticizer, and / or 0.05 to 0.8% by weight, preferably 0.1 to 0.6% by weight, of a flocculant, and / or The adhesive promoter is contained in an amount of 0.02 to 0.5% by weight, preferably 0.05 to 0.25% by weight.

[0085] In a more preferred embodiment, the concentrated self-degrading sunblock coating comprises all of the above in combination.

[0086] The concentrated self-decomposing light-shielding coating is preferably applied in a diluted form, for example, by diluting 1 mass equivalent of the concentrated composition with 1 to 10 mass equivalents of water, more preferably 1 mass equivalent of the concentrated composition with 2 to 5 mass equivalents of water.

[0087] On / off light blocking paint When the coating composition of the present invention is formulated as an on / off sunscreen coating, the amount of crosslinked starch in the composition is preferably 2 to 30 wt. %, more preferably 5 to 25 wt. %, and even more preferably 6 to 20 wt. %, based on the dry weight of the composition. Such compositions have the advantage of remaining intact for many months, such as 2 to 9 months, preferably 3 to 6 months. Such compositions have the further advantage of being readily removable by active washing with an appropriate detergent.

[0088] The concentrated on / off blackout coating preferably comprises, as a weight percent of the total composition: 25 to 60% by weight, preferably 30 to 55% by weight, of water, and 35 to 64% by weight, preferably 40 to 60% by weight, more preferably 45 to 55% by weight of a filler, and Contains 2 to 20% by weight, preferably 3 to 18% by weight, more preferably 4 to 15% by weight of crosslinked starch, More preferably, 0.05 to 0.8% by weight, preferably 0.1 to 0.5% by weight, of an antifoaming agent, and / or 0.01 to 0.8% by weight, preferably 0.05 to 0.4% by weight, of a thickener, and / or 0.1 to 1% by weight, preferably 0.2 to 0.8% by weight, of a wetting agent, and / or 0.001 to 1.0% by weight, preferably 0.005 to 0.5% by weight, of a biocide, and / or 0.1 to 5.0% by weight, preferably 0.5 to 3.0% by weight, of a plasticizer, and / or 0.05 to 0.8% by weight, preferably 0.1 to 0.6% by weight, of a flocculant, and / or The adhesive promoter is contained in an amount of 0.02 to 0.5% by weight, preferably 0.05 to 0.25% by weight.

[0089] In a more preferred embodiment, the concentrated on / off blackout coating comprises all of the above in combination.

[0090] The concentrated on / off blackout coating is preferably applied in diluted form, such as by diluting 1 mass equivalent of the concentrated composition with 1 to 10 mass equivalents of water, more preferably 1 mass equivalent of the concentrated composition with 2 to 5 mass equivalents of water.

[0091] Coating removal A distinct advantage of the present invention is that the biodegradable coating composition can be removed at any time by treatment with a cleaning composition. While cleaning compositions are generally intended to remove on / off coating compositions, those skilled in the art will also understand that self-degrading coating compositions may be removed in the same manner as on / off coating compositions.

[0092] Prior art coating compositions were generally removed by alkaline cleaning compositions having a high pH of about 12 to 14. This coating composition has the advantage that it can be removed with an environmentally friendly aqueous cleaning composition that includes an amylolytic enzyme, and optionally further includes a buffer, a thickener, a sequestering agent, and / or a surfactant.

[0093] Those skilled in the art will recognize which enzymes can be considered as starch-degrading enzymes.Whether an enzyme can be considered as a starch-degrading enzyme can be tested by subjecting a certain amount of dissolved starch to the enzyme in question under reaction conditions suitable for the enzyme.If starch is degraded (this can be confirmed by commonly known methods), the enzyme in question can be considered as a starch-degrading enzyme.

[0094] Preferably, the starch-degrading enzyme comprises alpha-amylase [EC 3.2.1.1] or beta-amylase [EC 3.2.1.2]. Starch-degrading enzymes may also be introduced by incorporating one or more bacteria ("probiotics") into the cleaning composition, which probiotics release at least one starch-degrading enzyme.

[0095] The amylolytic enzyme is preferably present in the aqueous cleaning composition in an amount of 0.001 to 1.0 wt %, preferably 0.01 to 0.5 wt %, more preferably 0.05 to 0.3 wt %, on a dry mass basis relative to the total composition.

[0096] The cleaning composition preferably further comprises a pH modifier. Suitable pH modifiers for stabilizing an enzyme solution at an appropriate pH for the type of enzyme are generally known and generally comprise at least one weak acid and its conjugate base, or a weak base and its conjugate acid. Alternatively, a strong acid or strong base may be used to set the pH within a specific range. Suitable acids and bases (and their conjugate acids / bases) are well known in the art and may include, for example, citric acid, formic acid, gluconic acid, hydrofluoric acid, hydrochloric acid, ammonia, carbonates, and bicarbonates.

[0097] When present, the pH modifier may be present in the composition in an amount of 0.05 to 10% by weight, preferably 0.1 to 7.5% by weight, more preferably 0.2 to 5.0% by weight, based on the total weight of the composition, on a dry basis. The pH modifier may set the pH of the cleaning composition to 2 to 14, preferably 3 to 9.

[0098] The cleaning composition preferably further comprises a thickening agent, which may be, for example, xanthan gum, cellulose, a cellulose derivative such as hydroxyethyl cellulose (HEC) or microfibrillated cellulose (MFC), a polyurethane thickener, clay, or hydrophobic silica.

[0099] When present, thickeners may be included in the cleaning composition in an amount of from 0.05 to 5% by dry weight of the total composition.

[0100] The cleaning composition preferably further comprises a sequestration agent, which may be, for example, ethylenediaminetetraacetic acid (EDTA), sodium citrate, gluconic acid, or N,N-dicarboxymethylglutamic acid tetrasodium salt (GLDA).

[0101] When present, the sequestrant may be included in the cleaning composition in an amount of from 1 to 20% by weight, preferably from 5 to 15% by weight, dry mass based on the total weight of the composition.

[0102] The cleaning composition preferably further comprises a surfactant, such as a silicone, phosphate, sulfosuccinate, or nonionic surfactant, such as an ethoxy or propoxy-containing fatty alcohol. When present, the surfactant may be present in the cleaning composition in an amount of 0.1 to 20 wt. %, preferably 0.5 to 15 wt. %, and more preferably 0.5 to 5 wt. % by dry weight, based on the total weight of the composition.

[0103] The cleaning composition may further preferably contain 0.001 to 1% by weight of a known anti-foaming agent.

[0104] In a more preferred embodiment, the cleaning composition comprises all of the above in combination.

[0105] The cleaning composition can be obtained by dispersing the ingredients in water and mixing appropriately.

[0106] Exterior structure containing coating composition The present invention further provides an exterior structure at least partially provided with a biodegradable coating composition as defined elsewhere. In this respect, the exterior structure is an artificial structure where human activity occurs, such as a house, an office, an industrial building, or an agricultural building such as a greenhouse. In a preferred embodiment, the coating composition is applied to the outer surface of the exterior structure. In a further preferred embodiment, at least the roof portion of the exterior structure is essentially covered with the biodegradable coating composition. This provides for regulation of the interior climate of the exterior structure, in particular heat reduction.

[0107] In a preferred embodiment, the exterior structure comprises one or more transparent panels. In a more preferred embodiment, the one or more transparent panels are arranged on the roof portion of the exterior structure. In a highly preferred embodiment, the exterior structure is an industrial building or a greenhouse, most preferably a greenhouse. When the coating of the present invention is applied to one or more transparent panels included in the exterior structure, preferably its roof portion, the interior climate is further regulated by light reduction.

[0108] The exterior structure can be any structure the interior of which requires heat reduction and / or shading. In a preferred embodiment, the coating composition is applied to the exterior surface of the exterior structure, particularly an industrial building or greenhouse, most preferably the exterior surface of a greenhouse.

[0109] Thus, application of the coating of the present invention can reduce temperatures within an exterior structure, whether or not the exterior structure includes transparent panels. Thus, application of the coating of the present invention to essentially opaque sections of an exterior structure provides heat reduction.

[0110] Additionally, light intensity can be reduced by at least partially, and preferably essentially completely, applying a coating to one or more transparent panels contained within the exterior structure, most preferably located in (at least) the roof portion of the exterior structure, which not only achieves light reduction but also further temperature reduction, collectively referred to as "shading."

[0111] The transparent panel included in the exterior structure can be any type of transparent panel, preferably a glass panel, a polycarbonate panel, a polyvinylidene fluoride (PVDF) panel, a polyacrylic panel, a polyvinyl chloride (PVC) panel, or a polyethylene panel.

[0112] The present invention relating to a method for regulating the internal climate of an exterior structure will be discussed below on the basis that the exterior structure is, for example, a greenhouse. However, the present invention is not limited to application to greenhouses, and any exterior structure may be provided with this biodegradable coating composition to achieve light and / or heat reduction therein, and thus benefit from the advantages achieved by the present invention.

[0113] The present invention further provides a method for regulating the interior climate of an exterior structure, preferably a greenhouse or industrial building, most preferably a greenhouse, comprising: a) providing the exterior structure at least in part with an aqueous biodegradable coating composition as defined elsewhere; and b) drying the aqueous biodegradable coating composition to obtain a biodegradable coating layer. The coating is preferably applied to the exterior surface of the exterior structure.

[0114] In a preferred embodiment, the exterior structure comprises one or more transparent panels. In a further preferred embodiment, at least one or more transparent panels is at least partially, preferably essentially completely, coated with the aqueous biodegradable coating composition.

[0115] For example, the climate inside a greenhouse can be adjusted by increasing or decreasing shading. After application and drying, the biodegradable coating composition of the present invention increases the shading inside the greenhouse. Increasing shading has the effect of reducing the light intensity inside the greenhouse, which can be beneficial for the growth of certain crops, especially in late spring or summer. Increasing shading also reduces the temperature inside the greenhouse, which is often suitable for late spring or summer.

[0116] Active or passive removal of the coating of the present invention increases the transparency of the panel and therefore increases the light intensity within the exemplary greenhouse. At the same time, removal has the effect of increasing the internal temperature. This can be advantageous, for example, in late summer or fall, when certain crops may benefit from enhanced light conditions and no longer require increased shading.

[0117] Coating the exterior structure and / or any transparent panels contained therein with the aqueous coating composition can be accomplished by any means. Preferably, the aqueous coating composition is applied by spraying or brushing the coating composition onto the exterior structure, including any transparent panels contained therein. This can be done manually, but can also be done using specialized equipment, such as specialized spraying equipment, including tanks with spray hoses and nozzles attached to an individual's back, a helicopter, or a drone. After application of the aqueous coating composition, a water layer forms on the surface of the transparent panel. Subsequent drying results in the formation of a dry coating layer, which provides light protection.

[0118] The transparent panels of the exemplary greenhouse, or any non-transparent portions of the exterior structure, need not be completely covered with the biodegradable coating composition. In some embodiments, portions or non-transparent portions of the transparent panels can be left uncovered to further regulate heat and light conditions. In other embodiments, in situations where the greenhouse includes multiple transparent panels, some of the panels can be completely covered while other transparent panels remain completely uncovered. This also provides for regulation of the greenhouse's internal climate.

[0119] However, in preferred embodiments, at least all of the transparent panels of the exemplary greenhouse roof are substantially completely covered with the coating composition, thereby maximizing shading of the greenhouse interior. In further preferred embodiments, all of the transparent panels of the exemplary greenhouse are substantially completely covered with the coating composition. When applying coatings to non-transparent portions of the exterior structure, partial or complete coverage is equally possible, with similar goals of heat reduction.

[0120] Drying the biodegradable coating composition does not have to be an active step. Drying of the coating composition is preferably accomplished by allowing the weather to bring about drying. However, in some embodiments, the drying step can be accelerated, for example, by blowing air or by applying heat.

[0121] The coating composition applied to a transparent panel or other location and then dried may also be referred to as a dried coating layer, or simply a coating layer. The coating layer comprises the crosslinked starch and filler, and other optional ingredients, in the same relative amounts as the aqueous coating composition defined elsewhere.

[0122] Both the self-degrading coating composition and the on / off coating composition can be removed by contacting the surface of the exterior structure with the dried coating layer with a cleaning composition as defined elsewhere, said contacting being achieved by any conceivable means, preferably by spraying or brushing, either manually or using specialized equipment as defined elsewhere.

[0123] Contacting the coating layer with a cleaning composition degrades the biodegradable coating layer, particularly the crosslinked starch contained therein, resulting in an at least partially degraded coating composition comprising amylose and / or amylopectin fragments.

[0124] Rinsing the exterior structure allows for the removal of at least partially decomposed coating composition. This results in an increase in internal temperature and, if the coating is applied to one or more transparent panels, an increase in light intensity. Rinsing can be accomplished with a water hose or by spraying with water. Preferably, however, rinsing is accomplished by allowing rain to rinse the exterior structure.

[0125] The washing process results in amylose and / or amylopectin fragments being transferred to the soil and / or surface water surrounding the outer structure. The amylose and amylopectin, as well as their fragments, can be further decomposed in the soil by microorganisms in an environmentally friendly manner. The same applies to other components of the cleaning composition. Therefore, the coating of the present invention and its removal are environmentally friendly and biodegradable.

[0126] Accordingly, the present invention further provides a method for removing a biodegradable coating layer comprising crosslinked starch and a filler as defined elsewhere from an exterior structure, preferably a transparent panel located within said exterior structure, comprising contacting said biodegradable coating composition on the exterior structure with a cleaning agent comprising an amylolytic enzyme as defined elsewhere, and rinsing the exterior structure.

[0127] In a more preferred embodiment, the biodegradable coating composition that is removed from an exterior structure, such as a greenhouse, is a coating composition formulated as an on / off coating composition that includes 2 to 30 wt. %, preferably 5 to 25 wt. %, and more preferably 6 to 20 wt. % crosslinked starch, based on dry weight.

[0128] Although for purposes of clarity and concise description, features are described herein as part of the same or separate embodiments, it will be understood that the scope of the present invention may include embodiments having all or any combination of the described features.

[0129] The invention will now be described with reference to the following non-limiting examples. [Example]

[0130] biodegradable Biodegradability is assessed using the standardized method OECD 301. In these examples, versions OECD 301A and / or OECD 301F are applied, which provide equivalent results in terms of biodegradability. Only the method for detecting COD differs.

[0131] Briefly, biodegradability is analysed as follows: A more detailed method description is available from the OECD. A suspension of the test composition in water with a solids content of 15 mg / L is inoculated with the microorganism and incubated in duplicate under aerobic conditions in the dark. A blank (also in duplicate) with the same amount of inoculum but without the test composition is run in parallel, as well as a reference compound (15 mg / L sodium acetate) with the same amount of inoculum. Assays containing the test composition and the control substance at the test concentration are also run to verify the degree of inhibition. All assays are run under gentle agitation and kept at 22°C throughout for 28 days.

[0132] COD (Chemical Oxygen Demand) is measured at the beginning and end of the assay, with further COD measurements taken on days 1, 4, 7, 11, 14, 17, 21 and 25. The test is expressed as a % biodegradability of the tested composition, with 100% biodegradability being an optimal result.

[0133] Fillers are generally inorganic minerals and, as such, are not "biodegradable," but they also do not contribute to the environmental impact of the coating compositions of the present invention. The same is true for water in aqueous compositions. Thus, the "biodegradability" of the coating compositions of the present invention is essentially determined by the binder (crosslinked starch), which is the primary organic component of the coating composition.

[0134] Weather resistance (abrasion resistance) To evaluate the weatherability of the coating layer, the following protocol is followed. The coating compositions were applied to two types of transparent panels: 4 mm thick standard glass panels (no specific treatment) or 200 μm PVC panels (5 Star Office, no specific treatment). Comparable results were obtained with the two types of panels, and the results shown are for the glass panels.

[0135] The weather resistance of the coating layer is analyzed based on the coating that is actually applied. The concentrated coating (recipe below) is prepared and dispensed by diluting it with water using 25% by weight of the concentrated coating and 75% by weight of water.

[0136] The coating layer is applied by spraying it with a pneumatic system that blows air at 2 bar through a special nozzle, generating tiny droplets. The coating is applied to the panels at a temperature of 22 (±2) °C and a relative humidity of 40-60%. To simulate the tilt of a greenhouse, the panels (glass or plastic) are tilted at an angle of 30° during application of the diluted coating composition.

[0137] The coating layer is allowed to dry at ambient temperature without the use of an air or heating system. Once the coating layer is dry, an evaluation of the weatherability of the coating layer can be performed. The coated panels are placed outside and allowed to age naturally under summer conditions with rain and UV rays from the sun, and are repeatedly analyzed for the following parameters: 1. To visually assess the degradation of the coating, photographs of the coating layer are taken in a light cabin using a normative light source (D65). 2. Light transmittance measurements of the coating layer are performed using a UV-Visible spectrophotometer (JASCO UV-Visible or JAZ20C from OCEAN OPTICS, which provide equivalent results). The light transmittance over the range of 400-800 nm is averaged to provide a single value for light transmittance, which allows the amount of light blocked by the coating layer to be quantified.

[0138] Between each measurement (image and light transmittance measurement), the coating is exposed to external weather conditions. The coating layer is placed on an external support inclined at 30° to replicate the slope of a greenhouse. As external conditions (temperature, rain, wind, etc.) are always different, tests are carried out in parallel on a reference coating layer with known performance.

[0139] Cleaning performance The on / off coating layer (and optionally the self-degrading coating composition) can be removed with a suitable cleaning composition.

[0140] Testing of the cleaning compositions was carried out using on / off coating layers that were left in open weather conditions for 15 weeks. The coating compositions were applied and allowed to dry as described above.

[0141] The cleaning composition was applied in the same manner as the coating composition. The cleaning composition was applied at a 1:6 weight dilution of the concentrated cleaning composition, the recipe of which is given below. The cleaning composition was left on the coated surface and allowed to dry as indicated by weather conditions.

[0142] The cleaning composition, and in particular the enzymes contained therein, degrades the binder structure, resulting in loss of adhesion to the substrate. Other components of the cleaning composition allow for the removal of fillers present in the coating layer.

[0143] The cleaning agent and coating layer are rinsed away by successive rain showers, the mechanical action of which dissolves the mixture of cleaning composition and coating layer.

[0144] Visual inspection of the coating layer is performed after rinsing. Cleaning performance is defined as optimal when no residue remains on the substrate. Cleaning performance is defined as medium when the binder has been removed but some filler is still present on the substrate.

[0145] Cleaning performance is defined as poor if the coating is still present on the substrate after rinsing.

[0146] Self-degrading blackout paint The table represents different autolyzing formulas (as concentrated solutions). In formulas 1-3, various amounts of TACKIDEX I231 (from ROQUETTE) were used. This gelatinized potato starch had already been cross-linked by the supplier using a phosphate-based cross-linker. In formula 4, TACKIDEX 036SP (from ROQUETTE) was used. This gelatinized potato starch was not cross-linked by the supplier. In formula 5, a non-cross-linked pea starch, TACKIDEX N735, was used. Formula 6 was prepared without starch.

[0147] The various raw materials listed in the table below were homogenized in a suitable vessel, with the stirring speed increased to above 800 RPM before adding the filler and reduced to below 600 RPM once sufficient dispersion of the powders was achieved.

[0148] The abrasion resistance of different formulas compared to the commercially available self-decomposing paint Eclipse F4 is shown in Figure 1. Formula 3 is equivalent to Eclipse F4 in terms of abrasion resistance. Formula 3 has higher abrasion resistance even after 12 weeks. Formulas 1 and 2 are also suitable as light-blocking paints.

[0149] The coating layers of Coatings 1-3 are similar to the reference throughout the week based on visual inspection. [Table 1] Antifoamant = Foamaster NXZ / BASF, thickener = Kelzan RD / CP KELCO, wetting agent = BYK 347 / BYK, flocculant = Texanol / EASTMANN, filler slurry (78 wt.% calcium carbonate) = Omyaflow 15-ME / OMYA, adhesion promoter = Silquest A1100 / MOMENTIVE, biocide = Acticide MBS / THOR, plasticizer = Neosorb 70 / 02 / ROQUETTE.

[0150] The biodegradability of Formulas 1-3 reaches 100% in 28 days using method OECD 301A performed on the entire coating composition.

[0151] The biodegradability of Formulas 1-3 reaches 96% in 28 days using method OECD 301F, with the filler replaced by water.

[0152] Light blocking paint on / off The ingredients listed in the table below were homogenized in a suitable vessel, with the stirring speed increased to above 800 RPM before adding the filler and reduced to below 600 RPM once sufficient dispersion of the powders was achieved. [Table 2] Antifoamant = Foamaster NXZ / BASF, thickener = Kelzan RD / CP KELCO, wetting agent = BYK 347 / BYK, flocculant = Texanol / EASTMANN, filler slurry (78 wt.% calcium carbonate) = Omyaflow 15-ME / OMYA, adhesion promoter = Silquest A1100 / MOMENTIVE, biocide = Acticide MBS / THOR, plasticizer = Neosorb 70 / 02 / ROQUETTE.

[0153] Regarding the starches used in formulas 7-10, In Formulas 7 and 9, various amounts of TACKIDEX I231 (available from ROQUETTE) were used. This pregelatinized potato starch had already been cross-linked by the supplier using a phosphate-based cross-linker. In Formulas 8 and 10, TACKIDEX 036SP (available from ROQUETTE) was used. This pregelatinized potato starch was not cross-linked by the supplier but was cross-linked in house using 11.4% cross-linker by weight of starch (Formula 8) or 10% cross-linker by weight of starch (Formula 10), the cross-linker being BACOTE 20 (available from MEL CHEMICALS).

[0154] The wear resistance of the different formulas is shown in Figure 2 in comparison with the following references: -Eclipse F4 - a self-degrading, light-resistant reference applied at a 1:3 dilution -Eclipse LD 2-On / Off Blackout Reference Applied at 1:3 Dilution All of the formulas 7 to 10 can be used as on / off light-blocking coatings. Formulas 8 and 10 have better performance than Formulas 7 and 9 due to their higher crosslinking degree.

[0155] Visual inspection revealed that all coating layers 7-9 were similar throughout the observation period. 20 weeks (5 months) is a moderate lifespan for an on / off coating composition before it is removed by a cleaning composition. Biodegradability for all coatings 7-10 was 98±2% based on OECD 301F.

[0156] Cleaning Composition Different cleaning compositions for removing on / off coating compositions are listed in the table below (as concentrated solutions).

[0157] Cleaner 1 is a pH-neutral cleaner. Enzymes are added to the formula to break down the starch coating. Other ingredients, such as surfactants, are added to improve cleaning performance.

[0158] Cleaner 2 is an acid cleaner in which citric acid is used as a pH modifier. The acidic pH of the formulation and the presence of enzymes allows for the breakdown of the starch coating layer.

[0159] Wash 3 is an acid wash in which tartaric acid is used as a pH modifier. No enzymes are used in this formula, but a sequestrant is added to aid in the removal of fillers. [Table 3] Antifoaming agent = SAG 1572 / VAN MEEUWEN, thickener = Kelzan RD / CP KELCO, surfactant = Berol 1 8 5 / NOURYON, pH modifier = citric acid / BRENNTAG, enzyme = Amplify Prime / NOVOZYME, sequestrant = gluconic acid / ROQUETTE.

[0160] Cleaners 1 and 2 provide optimal clearance of coating layers 7-10 without residue. Cleaner 3 also provides some cleaning, but was found to be unable to provide complete removal of the coating; resin and filler residues remained present on the substrate surface.

[0161] Example 2 Two identical wooden sheds, the interiors of which typically become hot under sunny summer conditions, were used as models for industrial buildings. The (opaque) roof portion of one of the sheds was coated with an on / off shade coating according to Equation 10. Under sunny summer conditions, the shed with the shade coating was significantly cooler than the shed without the shade coating. The coating composition could be removed with a cleaning composition containing amylolytic enzymes.

[0162] Insights drawn from examples It has been discovered that cross-linked starch can be used as a binder instead of conventional synthetic polymer binders to create a biodegradable coating composition that can be used, for example, as a greenhouse shading paint. Using cross-linked starch, shading performance is maintained or improved with higher biodegradability, providing a shading paint with less environmental impact. The present invention may be configured as follows. [Section 1] A biodegradable coating composition comprising a crosslinked starch and a filler, and optionally a polyol plasticizer. [Section 2] Item 1, further comprising at least one selected from the group consisting of water, and / or dispersants, wetting agents, leveling agents, adhesion promoters, biocides, antifoaming agents, flocculants, thickeners, pH modifiers, and antifreeze agents. The biodegradable coating composition according to item 1, further comprising at least one selected from the group consisting of water, dispersants, wetting agents, leveling agents, adhesion promoters, biocides, antifoaming agents, flocculants, thickeners, pH modifiers, and antifreeze agents. [Section 3] Item 3. The biodegradable coating composition according to Item 1 or 2, wherein the crosslinked starch is pregelatinized. [Section 4] Item 4. The biodegradable coating composition according to any one of Items 1 to 3, wherein the crosslinked starch has a crosslinking ratio, defined as the weight % of the crosslinking agent relative to the weight of the crosslinked starch, of 1 to 50%, preferably 5 to 25%. [Section 5] The crosslinked starch may be sodium trimetaphosphate crosslinked starch, ammonium zirconium carbonate crosslinked starch, copper crosslinked starch, magnesium crosslinked starch, borax crosslinked starch, zirconium crosslinked starch, titanium crosslinked starch (e.g., titanium lactate, titanium malate, titanium citrate, titanium ammonium lactate, polyhydroxy complex of titanium, titanium triethanolamine, or titanium acetylacetonate crosslinked starch), calcium crosslinked starch, aluminum crosslinked starch (e.g., aluminum lactate or aluminum citrate crosslinked starch), boron crosslinked starch, Item 5. The biodegradable coating composition according to any one of Items 1 to 4, wherein the crosslinked starch is chromium-crosslinked starch, iron-crosslinked starch, antimony-crosslinked starch, glyoxal-crosslinked starch, p-benzoquinone-crosslinked starch, polycarboxylate-crosslinked starch (e.g., citric acid, maleic acid, glutaric acid, succinic acid, phthalic acid, and / or malic acid-crosslinked starch), phosphorous-crosslinked starch, phosphate-crosslinked starch, silicate-crosslinked starch (e.g., tetraethyl orthosilicate (TEOS)), epichlorohydrin-crosslinked starch, periodate-crosslinked starch, dialdehyde-crosslinked starch, or anhydride-crosslinked starch. [Section 6] Item 6. The biodegradable coating composition according to any one of Items 1 to 5, wherein the polyol plasticizer is sorbitol, glycerol, ethylene glycol, polyethylene glycol, xylitol, glucose, fructose, galactose, mannitol, sucrose, maltitol, urea, or any mixture thereof. [Section 7] Item 7. The biodegradable coating composition according to any one of items 1 to 6, wherein the filler comprises at least one of calcium carbonate, titanium oxide, boehmite, mica, silicate, gypsum, barite, aluminum oxide, magnesium oxide, talc, clay, interference pigment, or any combination thereof. [Section 8] Item 8. The biodegradable coating composition according to any one of Items 1 to 7, wherein the amount of the crosslinked starch is 1 to 50% by weight, preferably 1.5 to 30% by weight, more preferably 2.0 to 20% by weight, and / or the amount of the polyol plasticizer is 0.05 to 20.0% by weight, preferably 0.5 to 15% by weight, more preferably 1 to 7% by weight, and / or the amount of the filler is 1 to 97% by weight, preferably 50 to 95% by weight, more preferably 75 to 94% by weight, all of which are expressed based on the dry weight of the composition. [Section 9] Item 9. The self-degrading biodegradable coating composition according to item 8, wherein the amount of cross-linked starch is less than 7% by weight, based on the dry weight of the composition. [Section 10] Item 9. The on / off type biodegradable coating composition according to item 8, wherein the amount of cross-linked starch is 2 to 30% by weight based on the dry weight of the composition. [Section 11] Item 11. An outer structure at least partially provided with the biodegradable coating according to any one of items 1 to 10. [Section 12] Item 12. The exterior structure of item 11, wherein the exterior structure is a greenhouse or an industrial building, and preferably the exterior structure comprises a transparent panel at least partially provided with the biodegradable coating composition. [Section 13] A method for regulating the internal climate of an exterior structure, preferably a greenhouse or industrial building, comprising: a) providing an aqueous biodegradable coating composition according to any one of items 2 to 10 on an outer surface of the exterior structure at least partially; and b) drying the aqueous biodegradable coating composition to obtain a biodegradable coating layer, wherein the exterior structure preferably comprises one or more transparent panels, and the transparent panels are at least partially, preferably completely, covered with the coating composition. [Section 14] Item 14. The method according to item 13, wherein the external structure is provided with the aqueous biodegradable coating composition by spraying or brushing. [Section 15] Item 15. The method of item 13 or 14, further comprising the step of removing the biodegradable coating layer, the step comprising contacting the biodegradable coating layer with an aqueous cleaning composition comprising an amylolytic enzyme, and optionally further comprising a sequestering agent, a surfactant, and / or a pH modifier; allowing the cleaning composition to at least partially degrade the biodegradable coating layer to obtain a degraded coating layer composition; and rinsing the degraded coating layer composition. [Section 16] Item 16. The method according to item 15, wherein the biodegradable coating layer contains 2 to 30% by weight of crosslinked starch, as a weight percent based on dry matter. [Section 17] 1. A method for removing a biodegradable coating layer comprising crosslinked starch and a filler, and optionally a polyol plasticizer, from an exterior structure, the method comprising contacting the biodegradable coating layer on the exterior structure with a cleaning agent comprising an amylolytic enzyme and rinsing the exterior structure. [Section 18] Item 11. The exterior structure according to item 11, or the method according to any one of items 13 to 17, wherein the one or more transparent panels are glass panels, polycarbonate panels, polyvinylidene fluoride (PVDF) panels, polyacrylic panels, polyvinyl chloride (PVC) panels, or polyethylene panels. [Section 19] Item 11. A method for preparing the biodegradable coating composition according to any one of items 1 to 10, comprising dispersing the crosslinked starch and the filler, and optionally the polyol plasticizer, in water.

Claims

1. A biodegradable coating composition for interior climate control of an exterior structure, comprising a cross-linked starch, a filler, and a urea and / or polyol plasticizer.

2. 10. The biodegradable coating composition of claim 1, further comprising water and / or at least one selected from the group consisting of a dispersant, a wetting agent, a leveling agent, an adhesion promoter, a biocide, an antifoaming agent, a flocculating agent, a thickener, a pH modifier, and an antifreeze agent.

3. The biodegradable coating composition according to claim 1 or 2, wherein the cross-linked starch is pre-gelatinized.

4. 4. The biodegradable coating composition according to claim 1, wherein the cross-linked starch has a cross-linking ratio, defined as the weight percentage of cross-linking agent relative to the weight of the cross-linked starch, of 1 to 50%.

5. 4. The biodegradable coating composition according to claim 1, wherein the cross-linked starch has a cross-linking ratio, defined as the weight percentage of cross-linking agent relative to the weight of the cross-linked starch, of 5 to 25%.

6. 6. The biodegradable coating composition according to any one of claims 1 to 5, wherein the crosslinked starch is sodium trimetaphosphate crosslinked starch, ammonium zirconium carbonate crosslinked starch, copper crosslinked starch, magnesium crosslinked starch, borax crosslinked starch, zirconium crosslinked starch, titanium crosslinked starch, calcium crosslinked starch, aluminum crosslinked starch, boron crosslinked starch, chromium crosslinked starch, iron crosslinked starch, antimony crosslinked starch, glyoxal crosslinked starch, p-benzoquinone crosslinked starch, polycarboxylate crosslinked starch, phosphite crosslinked starch, phosphate crosslinked starch, silicate crosslinked starch, epichlorohydrin crosslinked starch, periodate crosslinked starch, dialdehyde crosslinked starch, or anhydride crosslinked starch.

7. 7. The biodegradable coating composition according to claim 6, wherein the titanium cross-linked starch is a starch cross-linked with titanium lactate, titanium malate, titanium citrate, titanium ammonium lactate, a polyhydroxy complex of titanium, titanium triethanolamine, or titanium acetylacetonate.

8. 7. The biodegradable coating composition according to claim 6, wherein the aluminum cross-linked starch is a starch cross-linked with aluminum lactate or aluminum citrate.

9. 7. The biodegradable coating composition of claim 6, wherein the polycarboxylate cross-linked starch is a starch cross-linked with citric acid, maleic acid, glutaric acid, succinic acid, phthalic acid, and / or malic acid.

10. The biodegradable coating composition according to claim 6, wherein the silicate cross-linked starch is a starch cross-linked with tetraethyl orthosilicate (TEOS).

11. 11. The biodegradable coating composition according to any one of claims 1 to 10, wherein the polyol plasticizer is sorbitol, glycerol, ethylene glycol, polyethylene glycol, xylitol, glucose, fructose, galactose, mannitol, sucrose, maltitol, or any mixture thereof.

12. 12. The biodegradable coating composition of any one of claims 1 to 11, wherein the filler comprises at least one of calcium carbonate, titanium oxide, boehmite, mica, silicates, gypsum, barite, aluminum oxide, magnesium oxide, talc, clay, interference pigments, or any combination thereof.

13. 13. The biodegradable coating composition according to any one of claims 1 to 12, wherein the amount of the crosslinked starch is from 1 to 50 wt.%, and / or the amount of the polyol plasticizer is from 0.05 to 20.0 wt.%, and / or the amount of the filler is from 1 to 97 wt.%, all wt.% being expressed based on the dry weight of the composition.

14. 14. The biodegradable coating composition of claim 13, wherein the amount of the cross-linked starch is 1.5 to 30% by weight, the weight percentage being expressed based on the dry weight of the composition.

15. 14. The biodegradable coating composition of claim 13, wherein the amount of the cross-linked starch is 2.0 to 20% by weight, the weight percentage being expressed based on the dry weight of the composition.

16. 14. The biodegradable coating composition of claim 13, wherein the amount of the polyol plasticizer is 0.5 to 15 wt %, where wt % is expressed based on the dry weight of the composition.

17. 14. The biodegradable coating composition of claim 13, wherein the amount of the polyol plasticizer is 1 to 7 wt%, where wt% is expressed based on the dry weight of the composition.

18. 14. The biodegradable coating composition of claim 13, wherein the amount of the filler is 50 to 95 wt. %, the wt. % being expressed based on the dry weight of the composition.

19. 14. The biodegradable coating composition of claim 13, wherein the amount of the filler is 75 to 94 wt. %, where wt. % is expressed based on the dry weight of the composition.

20. 14. The self-degrading biodegradable coating composition of claim 13, wherein the amount of cross-linked starch is less than 7% by weight, based on the dry weight of the composition.

21. 14. The on / off type biodegradable coating composition according to claim 13, wherein the amount of cross-linked starch is 2 to 30% by weight, based on the dry weight of the composition.

22. An external structure at least partially provided with a biodegradable coating according to any one of claims 1 to 21.

23. 23. The exterior structure of claim 22, wherein the exterior structure is a greenhouse or an industrial building.

24. 24. The exterior structure of claim 23, wherein the exterior structure comprises a transparent panel at least partially comprising the biodegradable coating composition.

25. 22. A method for regulating the internal climate of an exterior structure, comprising: a) providing an aqueous biodegradable coating composition according to any one of claims 2 to 21 at least partially on an outer surface of the exterior structure; and b) drying the aqueous biodegradable coating composition to obtain a biodegradable coating layer.

26. 26. The method of claim 25, wherein the exterior structure is a greenhouse or an industrial building.

27. 27. The method of claim 25 or 26, wherein the exterior structure comprises one or more transparent panels, the transparent panels being at least partially covered with the coating composition.

28. 27. The method of claim 25 or 26, wherein the exterior structure comprises one or more transparent panels, the transparent panels being completely covered with the coating composition.

29. The method of any one of claims 25 to 28, wherein the exterior structure is provided with the aqueous biodegradable coating composition by spraying or brushing.

30. 30. The method of any one of claims 25 to 29, further comprising the step of removing the biodegradable coating layer, the step comprising contacting the biodegradable coating layer with an aqueous cleaning composition comprising an amylolytic enzyme, and optionally further comprising a sequestering agent, a surfactant, and / or a pH modifier; allowing the cleaning composition to at least partially degrade the biodegradable coating layer to obtain a degraded coating layer composition; and rinsing the degraded coating layer composition.

31. 31. The method of claim 30, wherein the biodegradable coating layer comprises, as a weight percentage on a dry matter basis, 2 to 30% by weight of cross-linked starch.

32. 1. A method for removing a biodegradable coating layer comprising crosslinked starch and a filler and a urea and / or polyol plasticizer from an exterior structure, the method comprising contacting the biodegradable coating layer on the exterior structure with a cleaning agent comprising an amylolytic enzyme and rinsing the exterior structure.

33. 22. A method for preparing a biodegradable coating composition according to any one of claims 1 to 21, comprising dispersing the crosslinked starch and the filler and the urea and / or polyol plasticizer in water.

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