WO2024129505A1 - Revêtements réfléchissants dans l'infrarouge proche basés sur des cristaux liquides cholestériques - Google Patents
Revêtements réfléchissants dans l'infrarouge proche basés sur des cristaux liquides cholestériques Download PDFInfo
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Definitions
- LIDAR Light Detection and Ranging
- LIDAR systems map out their environments by sending laser pulses outward. When the pulse contacts an object or obstacle, it reflects or bounces light back to the LIDAR unit. The system then receives the pulse and calculates the distance between it and the object, based on the elapsed time between emitting the light pulse and receiving the return light beam. As the beams return to the system, it begins forming a picture of what’s going on in the world around the vehicle and can use computer algorithms to piece together shapes for cars, people, and other obstacles.
- LIDAR uses the Near-Infrared region “NIR” of the electromagnetic spectrum, with wavelengths between 780 nm -2500 nm. NIR wavelengths are highly absorbed by dark colors due to existence of carbon black pigments in the vehicle coatings. If the light beams are absorbed, they cannot be reflected back and detected by the LIDAR system. This system therefore becomes unreliable with respect to the detection of dark coated vehicles. This presents considerable obstacles if we consider that dark colored cars, such as gray and black cars, are some of the most popular colors preferred by consumers and utilized in the car industry.
- NIR reflective pigments incorporated in the basecoat of the vehicle.
- Traditional vehicle coating systems typically have three layers: primer/basecoat/clearcoat.
- One solution has been to incorporate NIR reflective pigments in the basecoat layer, as shown in Fig. 1 A.
- the NIR radiation is mostly absorbed through the clearcoat, and partially absorbed and partly reflected by the basecoat.
- Another approach has been to incorporate NIR reflective pigments in the primer layer, also shown in Fig. IB. In this approach, the light emitted by a LIDAR sensor is absorbed through the clearcoat and basecoat layers and its partially reflected (and partially absorbed) by the primer layer.
- NIR reflecting dark pigments are extremely limited. Additional issues include jetness, color shift, particle settling and other instability issues which present a challenge with NIR reflecting pigments are incorporated in the basecoat and primer layers. Contaminations with carbon black pigments further hinders the NIR reflectivity in the basecoat and primer layers, leading to even further complexities. For the foregoing reasons, the current approaches are not desirable.
- CLCs cholesteric liquid crystals
- the pitch is determined by the concentration and the helical twist power of a chiral dopant, used in the synthesis of the CLCs.
- the helical pitch of CLCs will be discussed in further detail in the description section of this disclosure.
- the present invention pertains to clearcoat or topcoat compositions which comprise cholesteric liquid crystals in combination with a polymerizable monomer(s).
- the present disclosure further pertains to methods of developing and applying coatings, such as clearcoats or topcoats, which comprise cholesteric liquid crystals that are capable of reflecting light in the near-infrared region, such as for example in the wavelength range of 905 nm to 1550 nm.
- a coating composition for application on a substrate.
- the coating composition comprises at least one polymerizable monomer(s) and polymeric cholesteric liquid crystals (CLCs).
- the coating composition is preferably utilized as a clearcoat or topcoat on a substrate.
- the polymeric cholesteric liquid crystals have a helical pitch length effective to reflect light wavelengths in the near-infrared region, such as for example in a region of 905 nm to 1550 nm.
- polymeric CLCs which are mixed with the polymerizable monomer(s) - the CLCs have at least three different helical pitch lengths, effective to reflect light with wavelengths of 1010 nm, 1220 nm and 1440 nm.
- the polymerizable CLCs are first synthesized and developed into a bulk polymeric CLC material.
- three different polymerizable CLCs are synthesized in bulk polymeric form, and then broken down into micron sized chips.
- the different CLC chips with the varying pitch lengths are subsequently mixed with the polymerizable monomer(s) to create a mixture, and said mixture is then applied onto a substrate as a single layer.
- the polymerizable monomer(s) is the polymerized through curing, and a clearcoat or topcoat is formed containing CLCs which are capable of reflecting light of three different wavelengths.
- a coating composition for application on a substrate is disclosed.
- the coating composition comprises:
- CLCs polymeric cholesteric liquid cry stals
- the polymeric cholesteric liquid crystals (CLCs) have a helical pitch length effective to reflect light wavelengths in the near-infrared region.
- the polymeric cholesteric liquid crystals or “polymeric CLCs”, can be pre- synthesized prior to their mixture with the at least one polymerizable monomer(s), to form the coating composition.
- nematic liquid crystals can be obtained and combined with one or more chiral dopants, so that a helical structure is induced by the helical twisting power of the chiral dopants.
- the synthesis of the polymeric CLCs is controlled so that a specific helical pitch value, P. is achieved.
- a cholesteric liquid crystal mixture is combined with at least one polymerizable monomer(s) to form a coating composition.
- the coating composition is then applied to a substrate and polymerized through a curing process.
- the cholesteric liquid crystals have specific desired helical pitch length which is been predetermined and they are incorporated with the polymeric monomer(s) as a liquid mixture, rather than as polymeric CLC chips, disclosed in the prior embodiment.
- the cholesteric liquid cry stals in this coating composition can phase separate and form micron-sized droplets that will reflect light with wavelengths in the preset chosen region.
- the coating application process is repeated multiple times, for example three times.
- a layer is formed comprising CLCs which can reflect light of a different wavelength, thus resulting in combined coating layers which reflect light in the chosen region.
- a method of coating a substrate comprises: - applying a first coating composition comprising at least one polymerizable monomer(s) and cholesteric liquid crystals to form a first layer;
- - applying onto the first layer a second coating composition comprising at least one polymerizable monomer(s) and cholesteric liquid crystals to form a second layer; and -applying onto the second layer a third coating composition comprising at least one polymerizable monomer(s) and cholestenc liquid crystals to form a third layer.
- the cholesteric liquid cry stals in the first, second and third layers have a helical pitch length effective to reflect light wavelengths in the near-infrared region.
- the cholesteric liquid crystals have a helical pitch length effective for reflecting light with wavelengths in the range of 905 nm to 1550 nm.
- the first layer, second layer and third layer form a transparent clear coat or topcoat layer.
- a polymerizable CLC is first developed and is then applied onto a substrate a polymerized through a curing process to form a polymeric CLC layer that reflects light in a present wavelength region.
- the application process would be repeated multiple times, preferably three times.
- a polymerizable CLC would be applied, having different helical pitch lengths, capable of reflecting light in the near-infrared region. More specifically in this embodiment a of method of coating a substrate is disclosed, the method comprising:
- a third composition comprising a third polymerizable cholesteric liquid crystal mixture; wherein the first second and third polymerizable cholesteric liquid crystal mixtures comprise cholesteric liquid crystals with a helical pitch length effective to reflect light wavelengths in the near-infrared region.
- the application of the first, second and third compositions results in formation of a clear coat or topcoat layer.
- the polymerizable cholesteric liquid crystals in the first, second and third coating compositions have different helical pitch lengths, specifically effective to reflect wavelengths of 1010 nm, 1220 nm and 1440 nm.
- the polymerizable cholesteric liquid cry stal mixture of this embodiment can be applied onto a previously applied clearcoat layer, wherein the clearcoat layer and the CLC mixture can be cured together or can be cured in separate sequential steps. Three applications of three different layers would be necessary for this particular embodiment. In some embodiments, the polymerizable CLC mixture is applied in three different applications, and each of the three different layer is cured separately in a separate curing step.
- a coated article is disclosed.
- the coated article is produced with the coating compositions and coating methods disclosed herein. More particularly the coated article comprises an optional primer layer and/or optional basecoat layer and a clear coat layer.
- the clear coat layer comprises cholesteric liquid crystals having helical pitch length for effective reflection of light having wavelengths in the near-infrared region.
- FIG. 1A and FIG. IB show schematics for current NIR-reflective basecoat and primer coat systems.
- FIG. 2 shows a schematic diagram of the helical structure of cholesteric liquid crystals.
- FIG. 3 shows graphical depiction of reflection and transmission spectrum of cholesteric liquid crystal.
- FIG 4. Shows a schematic of light reflection from a clearcoat layer developed according to one of the embodiments of the present disclosure.
- the present disclosure relates to coatings to be applied on substrates, wherein the coatings incorporate cholesteric liquid crystals, which are effective to reflect light in the near-infrared region or “NIR”.
- the coatings are particularly useful in applications involving automobiles or transport of vehicles, wherein near-infrared sensing systems are utilized for recognition of vehicles.
- Cholesteric liquid crystals (CLCs) are self-assembled systems consisting of elongated (rod-like) chiral organic molecules, a schematic depiction of which can be seen in Fig. 2. They possess orientational order that locally the average direction of the long molecular axes of the constituent molecules are aligned along a common direction known as the liquid crystal (LC) director.
- birefringence refers to the double refraction of light in a transparent molecularly ordered material. This is manifested by the existence of orientation-dependent differences in refractive index.
- the experienced refractive index is known as the ordinary refractive index; if the polarization is parallel to the LC director, the experienced refractive index is n e and n 0 is known as the extraordinary refractive index.
- CLCs possess a spatial helical structure where the liquid crystal director twists around an orthogonal axis, known as the helical axis, as shown in Fig. 2.
- the liquid crystal director On a plane perpendicular to the helical axis, the liquid crystal director is unidirectional and does not vary’ with position.
- the liquid crystal director twists.
- the distance for the director to rotate 360° is known as the pitch, or helical pitch, and is denoted by “P” as show n in Fig. 2.
- a typical reflection and transmission spectrum of a cholesteric liquid crystal is show n in Fig. 3. The sum of the reflection and transmission is 100%, indicating there is no absorption.
- the reflected light is circularly polarized with the same handedness as the helical structure of the liquid crystals. If the incident light is unpolarized, it can be decomposed into two components: one left-handed circular polarization and the other one with right-handed circular polarization.
- the unit o HTP is pm' 1 .
- a positive value of HTP means the induced helical structure is right-handed, while a negative value of HTP means the induced helical structure is left-handed.
- commercially available nematic liquid crystals were used along with and chiral dopants and construct CLCs which reflect light in the wavelength region from 905 nm to 1550 nm. These wavelengths are of particular importance within the scope of this disclosure because current LIDAR systems largely employ wavelengths from 905 nm to 1550 nm. However, it is to be understood that these are non-liming examples of wavelengths to be used, and do not limit the broader scope of the present invention, which can utilize CLCs for reflection purposes of any desired wavelength, depending on the application for which it is intended.
- the average refractive index n and birefringence An of a ty pical CLC are about
- NIR near-infrared region
- CLC When a CLC is confined in a layer, its reflection depends on the orientation of the helical axis. It only reflects light when the helical axis is uniformly perpendicular to the layer. It is desirable that the CLCs have wide temperature regions, and they are stable and transparent for visible light.
- the CLCs prepared according to the methods disclosed herein are incorporated into coating compositions, for example clearcoat or topcoat coating compositions.
- coating compositions for example clearcoat or topcoat coating compositions.
- Such coatings can be used in multilayered automotive coating applications, and are particularly envisioned to be effective, when a basecoat or primer/basecoat combination layer has dark pigmented colors incorporated therein.
- the CLCs within the clearcoat or topcoat layer, the absorption issues which are common with darkly pigmented primer or basecoats will be mitigated, and reflection of specific w avelengths can occur based on the composition of the clearcoat not the underlying coats. This will lead to more efficient reflection properties and more accurate sensing capabilities with respect to LIDAR type systems, or other sensing systems which use light reflection as a means of operation.
- a coating composition for application on a substrate comprises:
- CLCs polymeric cholesteric liquid cry stals
- the polymeric cholesteric liquid crystals (CLCs) have a helical pitch length effective to reflect light wavelengths in the near-infrared region.
- the polymeric cholesteric liquid crystals or “polymeric CLCs”, can be presynthesized prior to their mixture with the at least one polymerizable monomer(s), to form the coating composition.
- nematic liquid crystals can be obtained and combined with one or more chiral dopants, so that a helical structure is induced by the helical twisting power of the chiral dopants.
- the synthesis of the polymeric CLCs is controlled so that a specific helical pitch value, P, is achieved. This will determine that reflective wavelength of the particular polymeric CLC synthesized.
- the concentration of the chiral dopant with respect to the concentration of the nematic liquid crystals can be adjusted (according to formulas described above) so that a desired helical pitch. P, is achieved.
- a polymerizable nematic liquid crystal monomer(s) can be combined with one or more chiral dopant and one or more photoinitiator(s) to produce a polymerized cholesteric liquid cry stal. Once this mixture is cured/crosslinked, through photo-curing or thermal curing, a bulk polymeric CLC is created. This bulk polymeric CLC material can then be broken down to polymeric CLC chips, of micron or nano size.
- these small polymeric CLC chips or particles can be incorporated directly with a polymeric monomer(s) (such as those used in clearcoat formulations). This mixture is then applied onto a substrate and the polymeric monomer is polymerized, at ambient temperatures, or through thermal or photo curing, to create a polymeric CLC containing coating layer.
- a polymeric monomer(s) such as those used in clearcoat formulations.
- only one coating layer is necessary 7 .
- Three different polymeric CLCs can be combined with the polymeric monomer(s) in this embodiment, having three different helical pitch values. P, so that they can reflect wavelengths of three different lengths. If the different CLCs are incorporated all in one coating composition, then only a single layer of coating is required to create a clearcoat or topcoat which has reflectivity of various wavelengths.
- the polymeric CLCs incorporated into the coating composition have different helical pitch lengths, effective to reflect light of wavelengths in the near-infrared region.
- the poly meric CLCs incorporated into the coating composition have different helical pitch lengths, effective to reflect light of wavelengths in the region of 800 nm to 2500 nm. or more specifically in the region of 905 nm to 1550 nm.
- the polymeric CLCs incorporated into the coating composition have different helical pitch lengths, effective to reflect light of wavelengths of 1010 nm, 1220 nm and 1440 nm.
- three different bulk polymeric CLCs are developed/synthesized, each having the three different reflective wavelength properties, and they are subsequently processed and broken down into micron or nano sized chips.
- the three different types of polymeric CLCs chips or particles are then mixed with a polymerizable monomer(s) and the mixture is coated onto a substrate and subsequently polymerized.
- the specific reflective wavelength chosen for a given mixture will depend on the coverage that is required for that application.
- cholesteric liquid crystals have a low viscosity and thus they are not capable of being coated. Therefore, development of polymeric cholesteric liquid cry stals which are able to be incorporated into existing polymer coatings is desirable.
- Various methods for developing cholesteric liquid crystals with a specific helical pitch value are known in the art.
- the pitch of a cholesteric liquid cry stal material may be tuned or achieved by combining liquid crystal materials in the nematic phase with a chiral material or chiral dopant, which is capable of inducing a cholesteric phase within the liquid crystal materials.
- the pitch will depend on the weight ratios or concentrations of nematic liquid crystal material to chiral dopant.
- Cholesteric liquid crystal compounds are known in the art and are described for example in U.S. Patent publications 4,293,435 and 5,332,522, 5,886,242, 5,847,068, 5,780,629, 5,744,057, the contents of which are incorporated herein by reference.
- Other cholesteric liquid crystal compounds can also be utilized for purposes of this disclosure such as commercially available CLCs with known helical pitch length, or nematic liquid crystal compositions which require combination of a chiral dopant compound for the conversion to the cholesteric phase.
- Such commercially available nematic compounds include RM23, RM 105, RM82, RM257, and RM96 available from Merck.
- chiral dopant compounds are also known in the art, for example chiral dopant LC756 available from BASF.
- One or more, crosslinkers, reducing agents, or photo-initiators can also be used for the polymerization of the cholesteric liquid cry stals, one such example of a photo-initiator being Benzophenone (BP), available from Sigma-Aldrich.
- BP Benzophenone
- An appropriate solvent can also be added during the synthesis of the cholesteric liquid crystals so that homogeneous mixture is achieved.
- the polymeric cholesteric liquid crystals are combined with at least one polymerizable monomer(s) so that a coating composition is formed.
- the polymerizable monomer(s) selected are preferably those which are appropriate for utilization in clearcoat and topcoat applications, which are common in multilayered coated articles, such as automobiles or transport vehicles.
- Non-limiting polymerizable monomer(s) can include monomers which can be cross-linked to form polyurethanes, polyesters, poly acrylates, poly ethers, and polyamines, or any other known polymerizable monomers which are suitable for clearcoat or topcoat compositions.
- Curing or crosslinking agents can further be incorporated in the coating compositions, so that ambient temperature curing, or thermal curing, or photo/UV curing can be initiated once the coating composition is applied onto a substrate.
- Further additives may also be incorporated into the coating compositions, such as including but not limited to including levelling agents, polymerization catalysts, rheology modifying agents, thickening agents, antioxidants, solvents, optional pigments and other known coating formulation additives.
- the coating composition formed from the mixture of at least one polymerizable monomer(s) and the polymeric CLCs is a transparent clearcoat coating composition, which is applied onto a basecoat or primer/basecoat layer having a darkly pigmented color, i.e.. comprising dark pigments.
- a basecoat or primer/basecoat layer having a darkly pigmented color, i.e.. comprising dark pigments.
- Such basecoat layers or primer layers can include those having dark gray or black colors for example, due to their incorporation of carbon black pigments.
- a cholesteric liquid cry stal mixture is combined with at least one polymerizable monomer(s) to form a coating composition.
- the coating composition is the applied to a substrate and polymerized through a curing process.
- the cholesteric liquid cry stals have specific desired helical pitch length which is been predetermined and they are incorporated with the polymeric monomer(s) as a liquid mixture, rather than as polymeric CLC chips, disclosed in the prior embodiment.
- the cholesteric liquid crystals in this coating composition can phase separate and form micron-sized droplets that will reflect light with wavelengths in the preset chosen region.
- the coating application process is repeated multiple times, for example three times. With each coating application, a layer is formed comprising CLCs which can reflect light of a different wavelength, thus resulting in combined coating layers which reflect light in the chosen region.
- a method of coating a substrate comprises:
- a first coating composition comprising at least one polymerizable monomer(s) and cholesteric liquid crystals to form a first layer
- a second coating composition comprising at least one polymerizable monomer(s) and cholesteric liquid crystals to form a second layer;
- a third coating composition comprising at least one polymerizable monomer(s) and cholesteric liquid crystals to form a third layer.
- the cholesteric liquid crystals in the first, second and third layers have a helical pitch length effective to reflect light wavelengths in the near-infrared region.
- the cholesteric liquid crystals have a helical pitch length effective for reflecting light with wavelengths in the range of 905 nm to 1550 nm.
- the first layer, second layer and third layer form a transparent clear coat or topcoat layer.
- the cholesteric liquid crystals contained in the first, second and third coating compositions have different helical pitch lengths. More specifically, helical pitch lengths are effective to reflect light having wavelengths of 1010 nm, 1220 nm and 1440 nm.
- the first layer, second layer or third layer can each incorporate the CLCs disclosed herein, although each layer has to have a different CLC having a different helical pitch length so that the required region of reflection can be covered by the reflection effected in the multiple layers.
- Either the first, second or third layer can incorporate the CLCs of 1010 nm, 1220 nm or 1440 nm, just as long as each layer incorporates a CLC different from other layers. Therefore, the order of the layers can vary and will not impact the ability 7 of the three layers in combination from being able to reflect light of wavelengths in the NIR region of 905 nm to 1550 nm.
- the layers are applied separately, followed by a curing or polymerization step after application of each layer.
- a primer coat or a basecoat is optionally applied on to the substate.
- a multilayered coating process is common, wherein a primer layer is first applied, followed by a pigmented basecoat layer, and finished with a protective clearcoat or topcoat layer (terms used interchangeably for purposes of this disclosure).
- the clear coat or topcoat layers disclosed here are applied onto a substrate having a dark pigmented primer coat or base coat thereon.
- a polymerizable CLC is first developed and is then applied onto a substrate a polymerized through a curing process to form a polymeric CLC layer that reflects light in a present wavelength region.
- the application process would be repeated multiple times, preferably three times.
- a polymerizable CLC would be applied, having different helical pitch lengths, capable of reflecting light in the near-infrared region. More specifically in this embodiment a of method of coating a substrate is disclosed, the method comprising:
- a third composition comprising a third polymerizable cholesteric liquid crystal mixture; wherein the first second and third polymerizable cholesteric liquid crystal mixtures comprise cholesteric liquid crystals with a helical pitch length effective to reflect light wavelengths in the near-infrared region.
- the application of the first, second and third compositions results in formation of a clear coat or topcoat layer.
- the polymerizable cholesteric liquid crystals in the first, second and third coating compositions have different helical pitch lengths, specifically effective to reflect wavelengths of 1010 nm, 1220 nm and 1440 nm.
- the polymerizable cholesteric liquid cry stal mixture of this embodiment can be applied onto a previously applied clearcoat layer, wherein the clearcoat layer and the CLC mixture can be cured together or can be cured in separate sequential steps. Three applications of three different layers would be necessary for this particular embodiment. In some embodiments, the polymerizable CLC mixture is applied in three different applications, and each of the three different layer is cured separately in a separate curing step.
- a coated article is disclosed.
- the coated article is produced with the coating compositions and coating methods disclosed herein. More particularly the coated article comprises an optional primer layer and/or optional basecoat layer and a clear coat layer.
- the clear coat layer comprises cholesteric liquid crystals having helical pitch length for effective reflection of light having wavelengths in the near-infrared region.
- the clear coat layer comprises: first layer comprising cholesteric liquid crystals with helical pitch lengths effective to reflect light of wavelength 1010 nm, 1220 nm or 1440 nm; a second layer comprising cholesteric liquid crystals with helical pitch lengths effective to reflect light of wavelength of 1010 nm, 1220 nm or 1440 nm; and a third layer comprising cholesteric liquid crystals with helical pitch lengths effective to reflect light of wavelength of 1010 nm, 1220 nm or 1440 nm.
- the helical pitch lengths of the cholesteric liquid crystals contained in the first, second and third layers of the coated articles disclosed herein are different.
- the clear coat layers of the coated articles disclosed herein incorporate at least one polymerizable monomer(s). such as the those disclosed in previous discussion relating to the coating methods and compositions described in previous sections of this disclosure.
- the coated articles of the present invention have clear coat layer which are effective in reflecting light of wavelengths in the range of 905 nm to 1550 nm.
- the coated articles disclosed herein can optionally include a primer layer and/or the optional basecoat layer comprise dark pigments, such as is the case for automotive or vehicles having darkly pigmented primer or basecoat layers.
- the clear coat or topcoat coating compositions intended to be used as part of this disclosure in the methods and coated articles disclosed herein can comprise polymeric monomer(s) that are capable of incorporation in solvent bome or water- bome coatings.
- the clear coat polymeric monomer(s) can be selected from a wide variety of compounds that are form either thermoplastic or thermosetting type polymers.
- the polymeric monomer(s) can from can be an acry lic ty pe polymers, which are commonly available and widely used for automotive applications and finishes.
- acrylic esters include methyl methacrylate, butyl methacrylate and 2- ethylhexyl acrylate.
- suitable co-polymerizable monomers include styrene and acrylonitrile. Where the acrylic polymer is of the thermosetting type, there should be present suitable functional monomers which can result in crosslinking.
- Examples would include hydroxyl containing acrylic monomers such as hydroxy ethyl methacrylate and hyroxypropyl methacrylate and acid containing acrylic monomers such as acrylic acid and methacrylic acid. These materials can be crosslinked with a curing agent such as an aminoplast condensate or a polyisocyanate. Examples of suitable aminoplasts are those described above.
- Polyisocyanates and blocked polyisocyanates can also be used as curing agents.
- suitable polyisocyanates include monomeric polyisocyanates such as toluene diisocyanate and 4,4'-methylene-bis-(cyclohexyl isocyanate), isophorone diisocyanate and isocyanate prepolymers such as the trimers of monomeric polymeric polyisocyanates such as those mentioned above.
- the polyisocyanate can be optionally blocked.
- suitable blocking agents are those materials which are capable of unblocking at elevated temperatures such as lower aliphatic alcohols such as methanol, oximes such as methyl ethyl ketoxime, and lactams such as caprolactam.
- Blocked isocyanates can be used to form stable one-package systems.
- Polyfunctional isocyanates with free isocyanate groups can be used to form two-package room temperature curable systems, which are well-known in the art.
- Polyesters can also be used in the formulation of the clear topcoat.
- these polyesters are polyester polyols which are designed to be cured with a polyisocyanate or with an aminoplast resin.
- the polyesters are formed by the poly esterification of an organic polycarboxylic acid or its functional equivalent thereof with an organic polyol.
- acids which can be used are phthalic acid, terephthalic acid, tetrahydrophthalic acid, hexa-hydrophthalic acid, azelaic acid and dimerized fatty acid including mixtures.
- suitable polyols are ethylene glycol, 1 ,4-butanediol.
- polycaprolactone-type polyesters may be employed which are formed from reaction of a cyclic lactone such as epsilon-caprolactone with a polyol or a hydroxy acid such as ethylene glycol and dimethylolpropionic acid.
- Polyurethanes may also be used as the polymer in the clear coat or topcoat coating composition.
- Well-know polymers in this category include poly(ester-urethane) polyols which can be cured with an aminoplast or polyisocyanate as described above. The polyester polyol is usually first prepared and then reacted with the polyisocyanate.
- polyesters which may be used are those mentioned above.
- the polyisocyanate can be aromatic, aliphatic and cycloaliphatic with aliphatic and cycloaliphatic being preferred because of their better ultraviolet light stability.
- the polyurethane-based coating compositions can be applied to the basecoat over both the metallic and elastomeric parts of a substrate, such as for example an automobile, and this allows for expanded potential surfaces which can be coating with the compositions described herein.
- the coating compositions When the coating compositions are applied onto a substrate, various known coating applications means can be utilized.
- the coating compositions can be sprayed on, through conventional spraying means including electrostatic spraying applications.
- Other known application techniques can include, brushing, dipping or flow coating techniques, although the manner of which the coatings disclosed herein are applied onto a substrate are not limited to any particular application means.
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Abstract
Sont divulguées des compositions de revêtement pour des applications sur un substrat, les compositions de revêtement comprenant un ou plusieurs monomères polymères et des cristaux liquides cholestériques. Les revêtements forment des revêtements transparents ou des couches supérieures capables de réfléchir la lumière de longueurs d'onde dans la région proche infrarouge. Sont également divulgués des procédés d'application de revêtements sur un substrat, les revêtements comprenant un ou plusieurs monomères polymères et des cristaux liquides cholesténiques capables de réfléchir la lumière dans la région proche infrarouge.
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US202263387044P | 2022-12-12 | 2022-12-12 | |
US63/387,044 | 2022-12-12 |
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WO2024129505A1 true WO2024129505A1 (fr) | 2024-06-20 |
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PCT/US2023/082903 WO2024129505A1 (fr) | 2022-12-12 | 2023-12-07 | Revêtements réfléchissants dans l'infrarouge proche basés sur des cristaux liquides cholestériques |
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6800337B1 (en) * | 1997-10-15 | 2004-10-05 | Basf Aktiengesellschaft | Thermal insulating coating |
CN109337489A (zh) * | 2018-09-06 | 2019-02-15 | 华南师范大学 | 一种红外反射涂料及其制备方法和应用 |
WO2022047096A1 (fr) * | 2020-08-27 | 2022-03-03 | Swimc Llc | Revêtement présentant une réflectance solaire améliorée |
-
2023
- 2023-12-07 WO PCT/US2023/082903 patent/WO2024129505A1/fr unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6800337B1 (en) * | 1997-10-15 | 2004-10-05 | Basf Aktiengesellschaft | Thermal insulating coating |
CN109337489A (zh) * | 2018-09-06 | 2019-02-15 | 华南师范大学 | 一种红外反射涂料及其制备方法和应用 |
WO2022047096A1 (fr) * | 2020-08-27 | 2022-03-03 | Swimc Llc | Revêtement présentant une réflectance solaire améliorée |
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