Reflective and insulating mineral paint

Abstract

The present invention relates to a mineral reflective insulating paint containing a waterborne mineral binder, a waterborne organic polymer, an insulating mineral filler, a reflective pigment and water, the dry weight of the paint comprising from 10% to 30% by weight, preferably from 15% to 20% by weight, of mineral binder, from 0.5% to 5% by weight, preferably from 1% to 4.5% by weight, of organic polymer, from 5% to 20% by weight of insulating mineral filler, from 5% to 15% by weight of reflective pigment. The mineral binder is a silicate, preferably potassium silicate, or slaked lime. The reflective and insulating paint has a binder portion that comprises one or more mineral binders mainly. An organic binder in a limited and minor amount may also be present to provide properties such as flexibility and attachment to the support. The portion of organics in the paint is limited, and in particular is below the threshold of 5% by weight.

Description

[0001] Reflective and insulating mineral paint

[0002] The present invention relates to a reflective and insulating mineral paint and its manufacturing method.

[0003] The sun's energy reaches Earth in the form of a combination of visible light, which allows us to see colors, infrared wavelengths, which are primarily responsible for heat, and ultraviolet rays.

[0004] The largest contribution to the internal heat gain of a structure comes from infrared rays.

[0005] Reflective paints are designed to reflect solar energy, including heat-generating infrared energy.

[0006] Currently, paints on the market are based on acrylic, styrene-acrylic, vinyl, or fluorine-based binders (PVDF, etc.). Most binders are organic and derived from petroleum. Many paints also use hollow plastic spheres, such as polymethyl methacrylate or PMMA. These paints may be designed to have relatively long lifespans, but all will eventually "flourish" and generate microparticles of plastic. Furthermore, paints based on petroleum-based binders are not classified as naturally non-flammable. To achieve such a classification, it is necessary to introduce specific fillers of varying degrees of danger.

[0007] One objective of the invention is therefore to propose a reflective and insulating paint, meeting the classifications of mineral paints.

[0008] Another object of the invention is to provide such a paint which is non-flammable.

[0009] Another objective of the invention is to provide such a paint which is of satisfactory economic cost and easy to apply on all supports.

[0010] Another objective of the invention is to provide such a paint which can be used both indoors and outdoors, on the usual building supports, such as concrete, wood, metal cladding, steel trays, plasterboard, old paints, and this on vertical surfaces as well as on roofs.

[0011] For this purpose, the invention relates to a mineral reflective insulating paint comprising a mineral binder in aqueous phase, an organic polymer in aqueous phase, an insulating mineral filler, a reflective pigment and water. The dry mass of the paint comprises from approximately 10 to 30% by mass, preferably from approximately 15 to approximately 20% by mass, of mineral binder, from approximately 0.5 to approximately 5% by mass, preferably from approximately 1 to approximately 4.5% by mass, of organic polymer, from approximately 5 to approximately 20% by mass of insulating mineral filler, from approximately 5 to approximately 15% by mass of reflective pigment.

[0012] This means that the paint comprises, relative to the total mass of the paint, from 10 to 30% by mass, preferably from 15 to 20% by mass of mineral binder; from 0.5 to 5% by mass, preferably from 1 to 4.5% by mass of organic polymer; from 5 to 20% by mass of insulating mineral filler; and from 5 to 15% by mass of reflective pigment. These contents correspond to the contents in the dry mass defined above and indicate the dry (or active) matter content for each ingredient, expressed relative to the total mass of the paint.

[0013] The paint has in particular a dry mass or dry extract of between approximately 20.5 and 85%, preferably between approximately 26 and approximately 59.5%. This dry extract is preferably expressed in mass relative to the total mass of the paint.

[0014] Preferably, given the nature of the mineral binder, it is incorporated into the mixture in the form of an aqueous solution or dispersion, and therefore counts in the quantity of water contained in the paint. The paint therefore contains a proportion of water coming from the mineral binder in aqueous phase.

[0015] Preferably, given the nature of the organic polymer, it is incorporated into the mixture in the form of an aqueous solution or emulsion, and therefore counts in the quantity of water contained in the paint. The paint therefore contains a proportion of water coming from the organic polymer in the aqueous phase.

[0016] Thus, the invention may in particular comprise or use from approximately 30 to approximately 70% by weight of a mineral binder in aqueous phase, from approximately 1 to approximately 10% by weight of an organic polymer in aqueous phase, from approximately 5 to approximately 20% by weight of insulating mineral filler, from approximately 5 to approximately 15% by weight of reflective pigment, and water in a quantity sufficient to reach 100% by weight.

[0017] Thus, the invention also relates to a method for manufacturing mineral paint, comprising the mixture (i) of approximately 30 to approximately 70% by weight of a mineral binder in aqueous phase, preferably having the dry mass previously defined, (2i) of approximately 1 to approximately 10% by weight of an organic polymer in aqueous phase, preferably having the dry mass previously defined, (3i) of approximately 5 to approximately 20% by weight of insulating mineral filler, (4i) of approximately 5 to approximately 15% by weight of reflective pigment, and (5i) if necessary water in a sufficient quantity to reach 100% by weight. The insulating and reflective paint comprises a binder part which comprises one or more mineral binders as the main component. An organic binder in a limited and minor quantity may also be present to provide properties such as flexibility and adhesion to the support.In a preferred embodiment, the proportion of organic ingredients (all organics present) is less than 5% by weight of the paint, which advantageously allows the paint to comply with the FD T30-808 Family 1. - Class 1 b1 (organic parts < 5%) and VOB / C DI N 18363 2.4.1 standard. Another advantage is that this paint cannot ignite. Thus, the total content of organic ingredients in the paint is less than or equal to 5% by mass, relative to the total mass of the paint, preferably ranging from 3.0 to 5.0% by mass, preferably from 4.0 to 4.9% by mass.

[0018] An organic ingredient is defined as one that is primarily, or even exclusively, composed of carbon, hydrogen, oxygen, and possibly nitrogen, phosphorus, and / or sulfur atoms.

[0019] For example, in the paint according to the invention, the organic ingredients comprise, or even consist of, the organic polymer, and possibly the additive(s) such as stabilizer, resins, anti-foam additive, rheology agent, dispersant.

[0020] According to other advantageous aspects of the invention, the paint comprises one or more of the characteristics described below, taken individually or in all technically possible combinations.

[0021] The mineral binder may comprise or consist of silicate or slaked (aerial) lime. A water-based silicate binder, for example a potassium, sodium or lithium silicate, preferably a potassium silicate, is preferred. Silicates, such as potassium silicate, may be characterized by their silicate / metal oxide molar ratio, and this is advantageously 2 to 5, with a preference for 4.

[0022] The organic polymer(s) present are in aqueous phase, for example in dispersion, solution or aqueous emulsion.

[0023] The paint may in particular comprise a styrene acrylic copolymer, an acrylic polymer, a polyvinylidene fluoride (PVDF), a vinyl co- or ter-polymer, a fluoroethylene / vinyl ether copolymer (FEVE), a urethane alkyd resin, an epoxy alkyd resin, a hybrid polysiloxane, namely in particular a polysiloxane grafted onto acrylic, or a mixture of at least two organic polymers of the same category or of two different categories. The paint may also comprise, instead of the above, or in addition, a polymer of natural origin such as a polysaccharide, a polypeptide or a protein, a plant resin (e.g. rosin, elemi, gum arabic, frankincense, myrrh, sandarac, etc.), or a mixture of at least two polymers of natural origin of the same category or of two different categories.

[0024] A styrene acrylic copolymer, an acrylic polymer, an alkyd urethane or alkyd epoxy resin, a hybrid polysiloxane, alone or in combination with each other, preferably in aqueous dispersion or in emulsion, in particular for better longevity, are preferred.

[0025] The polymers preferably have a low glass transition temperature (TG), in particular between about -20 and about +15°C, preferably between about -5 and about 10°C, and / or, preferably, a TMMF (minimum film formation temperature) close to 0°C. This makes it possible in particular to avoid the use of plasticizer or organic cosolvent.

[0026] Examples of emulsion polymers: Styrene acrylic Acronal ® S 559 from BASF, hybrid polysiloxane Acronal ® S 813 from BASF, PVDF polymer KYNAR AQUATEC® FMA-12, CRX or ARC (PVDF and acrylic blend) from ARKEMA, vinyl terpolymer VINNAPAS® EAF 375 from WACKER, FEVE polymer LUMIFLON FE4300 from AGC.

[0027] Mineral fillers are solid, insoluble, non-reactive inorganic substances used primarily to modify the mechanical, thermal, or aesthetic properties of a material. The primary function of an insulating filler is to limit the conduction of heat or electricity.

[0028] The insulating mineral fillers are preferably siliceous fillers or ceramic fillers. They can be spherical and hollow, in the form of aerogel or microporous granules, particularly silica-based. A mixture of several fillers or fillers of different particle sizes is preferred, in order to preferably have a Gaussian-type particle size curve.

[0029] These may in particular be hollow glass spheres, in particular borosilicate glass, or hollow ceramic spheres. The hollow ceramic spheres preferably have a true density of between 0.65 and 0.85 and / or a particle size of 20 to 500 μm. The hollow glass spheres preferably have a true density of between 0.08 and 0.4 and / or a particle size of 10 to 80 μm. Examples of hollow spheres: E-SPHERES® SL150 ceramics from ENVIROSPHERES®, iM16K borosilicate glass from 3M. It may also be an aerogel, preferably formed from SiC>2 treated to be hydrophobic, preferably with a particle size of between 1 and 100 μm. Treatments for making SiC>2 hydrophobic are known, for example a silane treatment. These treatments are well known and commonly used by manufacturers. Example of silica aerogel: Quartzene Z2HI from SVENSKA AEROGEL or Enova® Aerogel IC3110 from CABOT.Silica aerogels are remarkable thermal insulators because their structure effectively limits heat transfer by convection, conduction, and radiation. With a very low thermal conductivity (approximately 0.01 W / m K), they are considered one of the best thermal insulators available.

[0030] It may also be silica-based granules, preferably composed of SiO2, with a particle size of between 10 and 1000 pm. Example of TEGO® Therm H PG 4000 silica granules from the company EVONIK.

[0031] It is also possible to mix two or more of these types of fillers.

[0032] The pigments are preferably mineral, and advantageously reflective.

[0033] A treated TiO2 can be used. TiO2 can be in rutile form. The treatment can notably consist of the creation of a core-shell structure, the core being the pigment, the shell being a (very thin) layer of silicon allowing to block free radicals, a potential cause of polymer degradation. In the case of TiO2, this structure can also be covered by a (very thin) layer of aluminum allowing the reflection of IR. Such TiO2-based pigments are known and commercially available, for example the treated TiO2 ALTIRIS® 800 from the company VENATOR.

[0034] One or more colored reflective pigments may also be used, such as, for example: iron oxide PY42 (yellow ochre), nickel yellow PY53, bismuth yellow PY184, mixed oxide yellow PY216, red iron oxide PR101, ultramarine violet PV15, chromium oxide green PG17, titanium cobalt green PG50, manganese oxide PBk33, complex inorganic pigment of black mixed oxide of iron (III) and chromium (III) PBr29.

[0035] It is also possible to mix the TiO2-based pigment and at least one colored pigment.

[0036] The invention also relates to any usual building support, interior or exterior, such as a room or wall made of concrete, wood, metal cladding, steel trays, plasterboard, old paint, etc., totally or partially coated with one or more layers of reflective and insulating paint according to the invention. The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example.

[0037] Example 1:

[0038] The insulating and reflective paint is composed of: % dry extract weight / paint weight means the mass share of the dry (active) compound in relation to the total mass of the paint (water included).

[0039] Potassium silicate in solution in water, dry extract 30 and 40% (by weight), has a silica / potassium molar ratio of 3.8.

[0040] The silicate stabilizer has a solids content of 50% (by weight). The styrene acrylic copolymer has the following characteristics: solids content 50%

[0041] ±1% (by weight), pH 6 to 7.5, Viscosity 70-4000 mPa.s at 23°C, average particle size 0.15 pm, TMMF 3°C, density 1.03, TG 5°C.

[0042] Hollow spheres of borosilicate glass have the following characteristics: actual density 0.3, average diameter 15 pm. The rutile-form TiC>2 is treated with a layer of SiC>2, then covered with alkali-resistant aluminum oxide: density 4.2, average particle diameter 0.8 pm.

[0043] Example 2:

[0044] The insulating and reflective paint is composed of:

[0045] Potassium silicate in solution in water, dry extract 30 and 40% (by weight), has a silica / potassium molar ratio of 3.8.

[0046] The silicate stabilizer has a dry extract of 50% (by weight).

[0047] The styrene acrylic copolymer has the following characteristics: solids content 50% ±1% (by weight), pH 6 to 7.5, Viscosity 70-4000 mPa.s at 23°C, average particle size

[0048] 0.15 pm, TMMF 3°C, density 1.03, TG 5°C.

[0049] The organic alkyd epoxy emulsion resin has the following characteristics: solids content 42% ±1% (by weight), TMMF 0°C, density 1.00. The silicon aerogel has the following characteristics: actual density 0.2, average diameter 4.65 pm, thermal conductivity 28 to 33 mW / m K, BET specific surface area 100 to 300 m 2 / g.

[0050] The silica-based granules have the following characteristics: actual density 0.3, average diameter 30 pm, thermal conductivity 30 mW / m K, BET specific surface area 190 m 2 / g.

[0051] Rutile-form TiC>2 is treated with a layer of SiC>2, then covered with alkali-resistant aluminum oxide: density 4.2, average particle diameter 0.8 pm.

[0052] The final paint has a dry extract of 30 to 50% by weight (relative to the total weight of the paint) and 40 to 70% by volume (relative to the total volume of the paint), the volatile part comes from the water contained in the emulsions or solution as well as the added water.

[0053] Laboratory results demonstrated a Solar Reflectance Index (SRI) of 112. SRI is the ability of a roofing material to reflect solar energy. Calculated from Solar Reflectance (SR) and Thermal Emittance (EI): Index on a scale of 0 to 100 which is defined by: SRI = 0 for a reference black body. SRI = 100 for a standard white color. SRI values ​​can exceed 100.

[0054] Example 3:

[0055] The potassium silicate solution is replaced by a sodium silicate solution in the composition of example 1 or 2.

[0056] Example 4:

[0057] The potassium silicate solution is replaced by a lithium silicate solution in the composition of example 1 or 2.

[0058] Example 5:

[0059] The potassium silicate solution is replaced by an air lime solution in the composition of example 1 or 2.

[0060] Example 6:

[0061] The aqueous phase styrene acrylic copolymer is replaced by an aqueous phase acrylic resin or polymer in the compositions of Examples 1-5.

[0062] Example 7:

[0063] The aqueous styrene acrylic copolymer is replaced by an aqueous vinyl copolymer resin in the compositions of Examples 1-5.

[0064] Example 8:

[0065] The aqueous styrene-acrylic copolymer is replaced by a hybrid silicone resin (hybrid polysiloxane Acronal ® S 813 from BASF) in the aqueous phase in the compositions of Examples 1-5.

[0066] Example 9: The aqueous phase styrene acrylic copolymer is replaced by an aqueous phase PVDF resin (KYNAR AQUATEC® FMA-12) in the compositions of Examples 1-5.

[0067] Example 10: The aqueous phase styrene-acrylic copolymer is replaced by a resin

[0068] FEVE (LUMIFLON FE4300 from AGC) in aqueous phase in the compositions of examples 1-5.

[0069] The solar reflectance index of the compositions of Examples 3 to 10 was measured as described in Example 2, and corresponds to that of Examples 1 and 2, to within plus or minus 1 point (uncertainty of the measurement).

Claims

CLAIMS 1. Mineral reflective insulating paint containing an aqueous-phase mineral binder, an aqueous-phase organic polymer, an insulating mineral filler, a reflective pigment and water, the paint comprising, relative to the total mass of the paint, from 10 to 30% by mass, preferably from 15 to 20% by mass, of mineral binder, from 0.5 to 5% by mass, preferably from 1 to 4.5% by mass, of organic polymer, from 5 to 20% by mass of insulating mineral filler, from 5 to 15% by mass of reflective pigment.

2. Paint according to claim 1, characterized in that it comprises or uses from 30 to 70% by weight of a mineral binder in aqueous phase, from 1 to 10% by weight of an organic polymer in aqueous phase, from 5 to 20% by weight of insulating mineral filler, from 5 to 15% by weight of reflective pigment, and water in sufficient quantity to reach 100% by weight.

3. Paint according to claim 1 or 2, characterized in that the total content of organic ingredients in the paint is less than or equal to 5% by mass, relative to the total mass of the paint, preferably ranging from 3.0 to 5.0% by mass, preferably from 4.0 to 4.9% by mass.

4. Paint according to any one of claims 1 to 3, characterized in that the mineral binder is a silicate, preferably potassium silicate, and slaked lime.

5. Paint according to any one of claims 1 to 4, characterized in that the organic polymer is a styrene acrylic copolymer, an acrylic polymer, a vinyl co- or ter-polymer, a polyvinylidene fluoride (PVDF), a fluoroethylene / vinyl ether copolymer (FEVE), a urethane alkyd resin, an epoxy alkyd resin, a hybrid polysiloxane, a polymer of natural origin, or a mixture of at least two of these polymers.

6. Paint according to any one of claims 1 to 5, characterized in that the insulating mineral filler comprises silica and / or ceramic particles, preferably glass or borosilicate glass particles.

7. Paint according to claim 6, characterized in that the silica or ceramic particles are in the form of hollow spheres, aerogel or microporous granules.

8. Paint according to claim 7, characterized in that it comprises hollow spheres of glass or borosilicate glass or ceramic; preferably the hollow ceramic spheres have a real density of between 0.65 and 0.85 and / or a particle size of 20 to 500 pm, and the hollow glass spheres have a real density of between 0.08 and 0.4 and / or a particle size of 10 to 80 pm.

9. Paint according to claim 7 or 8, characterized in that it comprises a hydrophobic silica aerogel, preferably having a particle size of between 1 and 100 pm; and / or silica granules, preferably having a particle size of between 10 and 1000 pm.

10. Paint according to any one of claims 1 to 9, characterized in that the reflective pigment is TiCh, preferably TiC>2 particles coated with silicon, and optionally with an aluminum layer as an outer layer.

11. Paint according to any one of claims 1 to 10, characterized in that it comprises 50% by weight of a mineral binder, 5% by weight of an organic polymer in aqueous phase, 10% by weight of insulating mineral filler, 10% by weight of reflective pigment, and water in sufficient quantity to reach 100% by weight.

12. Method for manufacturing the mineral paint according to any one of claims 1 to 11, comprising mixing (i) from 30 to 70% by weight of a mineral binder in aqueous phase, containing from 10 to 30% by weight of mineral binder, (2i) from 1 to 10% by weight of an organic polymer in aqueous phase, containing from 0.5 to 5% by weight of organic polymer, (3i) from 5 to 20% by weight of insulating mineral filler, (4i) from 5 to 15% by weight of reflective pigment, and (5i) if necessary water in sufficient quantity to reach 100% by weight.

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