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US 2020/0165471 A1Published application
Surface functionalized titanium dioxide nanoparticles
AssigneeBASF SE
InventorsReinhold OEHRLEIN, Raphael DABBOUS, Michelle RICHERT, Gabriele BAISCH
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Abstract
The present invention relates to surface functionalized titanium dioxide nanoparticles, a method for its production, a coating composition, comprising the surface functionalized titanium dioxide nanoparticles and the use of the coating composition for coating holo-grams, wave guides and solar panels. Holograms are bright and visible from any angle, when printed with the coating composition, comprising the surface functionalized tita-nium dioxide nanoparticles.
Claims17
1:
- Surface functionalized titanium dioxide nanoparticles treated with
- a) a phosphonate of formula:
- or a mixture of phosphonates of formula (I), wherein:
- R1 and R2 are independently of each other hydrogen, or a C1-C4alkyl group,
- R3 is a group CH2═CH—, or a group of formula —[CH2]n—R4, wherein
- n is an integer of 1 to 12,
- when n>3 one —CH2— may be replaced by —S— with the proviso that S is not directly linked to P, or R4,
- R4 is hydrogen, or a group of formula
- R5 is hydrogen, or a C1-C4alkyl group,
- R6 is hydrogen, or a C1-C4alkyl group,
- X1 is O, or NH, and
- b) bonded with an alkoxide of formula R7O− (II) and/or
- wherein:
- R7 is a C1-C8alkyl group, which may be interrupted one or more times by —O— and/or substituted one or more times by —OH,
- R8 is hydrogen, or a C1-C4alkyl group,
- R9 is hydrogen, —CH2OH, —CH2SPh, —CH2OPh, or a group of formula R10—[CH2OH—O—CH2]n1—,
- n1 is an integer of 1 to 5,
- X2 is O, or NH,
- R10 is a group of formula —CH2—X3—CH2—C(═O)—CR11═CH2,
- X3 is O, or NH, and
- R11 hydrogen, or a C1-C4alkyl group.
18 more elements
2:
- The surface functionalized titanium dioxide nanoparticles according to claim 1, which have a size from 1 nm to 40 nm.
3:
- The surface functionalized titanium dioxide nanoparticles according to claim 1, wherein the weight ratio of titanium dioxide nanoparticles to phosphonate(s) of formula (I) and alkoxide(s) of formula (II) and (III) is in the range of from 99-1 to 50-50.
4:
- The surface functionalized titanium dioxide nanoparticles according to claim 3, wherein the weight ratio of phosphonate(s) of formula (I) and alkoxide(s) of formula (II) and (III) varies from 1-99 to 50-50.
5:
- The surface functionalized titanium dioxide nanoparticles according to claim 1, which exhibit a refractive index of greater than 1.70, when coated on a glass plate and dried at 60° C.
6:
- The surface functionalized titanium dioxide nanoparticles according to claim 1, wherein in the phosphonate of formula (I):
- R1 and R2 are hydrogen,
- R3 is a group CH2═CH—, or a group of formula —[CH2]n—R4, wherein
- n is an integer of 1 to 5, and
- R4 is hydrogen, or a group of formula
2 more elements
7:
- The surface functionalized titanium dioxide nanoparticles according to claim 1, wherein the alkoxide of formula (III) is derived from at least one of the following alcohols:
8:
- The surface functionalized titanium dioxide nanoparticles according to claim 1, which is:
- a) treated with a phosphonate of formula
- b) bonded with an alkoxide of formula EtO− (D-2), iPropO− (D-4) and
- or
- a) treated with a phosphonate of formula
- and
- b) bonded with an alkoxide of formula EtO− (D-2) and iPropO− (D-4.
4 more elements
9:
- A coating composition, comprising the surface functionalized titanium dioxide nanoparticles according to claim 1 and a solvent.
10:
- A security, or decorative element, comprising a substrate, which may contain indicia or other visible features in or on its surface, and on at least part of the said substrate surface, a coating, comprising the surface functionalized titanium dioxide nanoparticles according to claim 1.
11:
- A method for forming a surface relief microstructure on a substrate, the method comprising:
- a) forming a surface relief microstructure on a discrete portion of the substrate;
- and
- b) depositing the coating composition according to claim 9, on at least a portion of the surface relief microstructure.
1 more element
12:
- The method according to claim 11, wherein step a) comprises:
- a1) applying a curable compound to at least a portion of the substrate;
- a2) contacting at least a portion of the curable compound with surface relief microstructure forming means;
- and
- a3) curing the curable compound.
2 more elements
13:
- A process for preparing titanium dioxide nanoparticles, the process comprising:
- (a) adding a solution of concentrated hydrogen chloride (33% in water) diluting this solution with half volume of distilled water (60-29.8/volume-volume) diluting this solution with additional ethanol (90-1910/volume-volume) (resulting in solution I) to a solution of titanium-tetra-iso-propoxide first stirred in (absolute) ethanol (10-90/weight-volume) resulting in a solution II, both volumes of the solutions I and II being equal,
- (b) stirring the obtained clear solution for 5 days at room temperature, and
- (c) evaporating the clear solution at 20-30° C./20 mm until a constant weight is achieved to obtain titanium dioxide nanoparticles.
1 more element
14:
- The process according to claim 13, comprising
- d) dissolving the titanium dioxide nanoparticles obtained in step c) in a solvent, such as, for example, ethanol, or isopropanol,
- e) adding the phosphonate(s) of formula (I) and optionally the alcohol of formula
- and
- (e) stirring the mixture obtained in step (e) until a transparent solution is obtained, and (d) evaporating the mixture until the weight remains constant, wherein:
- R8 is hydrogen, or a C1-C4alkyl group,
- R9 is hydrogen, —CH2OH, —CH2SPh, —CH2OPh, or a group of formula R10—[CH2OH—O—CH2]n1—,
- n1 is an integer of 1 to 5,
- X2 is O, or NH,
- R10 is a group of formula —CH—X3—CH2—C(═O)—CR11═CH2,
- X3 is O, or NH, and
- R11 hydrogen, or a C1-C4alkyl group.
9 more elements
15:
- Titanium dioxide nanoparticles obtained by the process according to claim 13, which have a particle size from 1 nm to 40 nm and a TiO2-content of at least 40% by weight, a film of which dried at 25° C. shows a refractive index of greater than 1.70 (589 nm).
16:
- The titanium dioxide nanoparticles according to claim 15, which are storable at 4° C. for at least 3 months and can be redissolved in methanol, ethanol, propanol, 2-methoxy ethanol, iso-propanol, 2-iso-propoxy ethanol, butanol, ethyl acetate, propyl acetate and butyl acetate.
17:
- A process, comprising coating an article with the coating composition according to claim 9, where the article is selected from the group consisting of a hologram, a wave guide and a solar panel.