1. A method for estimating a temperature sensed upon contact with a surface comprising:
contactlessly applying pulsed heating to the surface;
contactlessly measuring a temperature change of the surface over time resulting from the pulsed heating;
determining a regression line for a function describing the temperature change;
calculating a gradient m of the regression line;
calculating a mean amplitude a of individual temperature oscillations produced by the pulsed heating;
determining a value of a parameter (vl) for the surface defined as:
vl
=
1
m
\xb7
a
;
\u2062
and
estimating the temperature sensed upon contact by comparing the value of the parameter (vl) for the surface with a set of known values of the parameter for a respective set of reference materials.
2. The method of claim 1 further comprising modifying the surface in order to normalize a color andor a transmission behavior of the surface.
3. The method of claim 2 wherein the surface is modified by applying at least one of a sticker, a tape, a liquid, a paste, and carbon black particles.
4. Apparatus for estimating a temperature sensed upon contact with a surface, comprising:
a heat source for applying pulsed contactless heating to the surface;
a thermometer for contactless measurement of a temperature of the surface; and
an evaluation unit determining a regression line for a function describing a temperature change over time during the pulsed heating, calculating a gradient m of the regression line, calculating a mean amplitude a of individual temperature oscillations produced by the pulsed heating, determining a value of a parameter (vl) for the surface defined as:
vl
=
1
m
\xb7
a
;
\u2062
and
estimating the temperature sensed upon contact by comparing the value of the parameter (vl) for the surface with a set of known values of the parameter for a respective set of reference materials.
5. The apparatus of claim 4, wherein the heat source comprises a rotatable screen having at least one opening, thermal energy being applied to the surface through the opening.
6. A method for estimating a temperature sensed upon contact with a surface comprising:
applying pulsed heating to the surface;
measuring a temperature change over time of the surface during the pulsed heating cycles;
determining a regression line for a function describing the temperature change;
calculating a gradient of the regression line;
calculating a mean amplitude of individual temperature oscillations produced by the pulsed heating;
performing a calibration utilizing a plurality of reference samples each having a respective known value of heat penetration coefficient, the calibration comprising assignment of a respective parameter to each respective value of the heat penetration coefficient known for each of the plurality of reference samples;
generating correlations between the parameters of each reference sample, the respective heat penetration coefficient values of each reference sample, and respective contact temperatures of each reference sample; and
estimating the temperature sensed upon contact based upon the correlations.
7. The method of claim 6 further comprising modifying the surface prior to the applying pulsed heating step in order to normalize a color andor a transmission behavior of the surface.
8. The method of claim 7 wherein the surface is modified by applying at least one of a sticker, a tape, a liquid, a paste, and carbon black particles.
9. The method of claim 6, wherein the application of pulse heating is accomplished by a heat source comprising a rotatable screen having at least one opening, the heating being applied to the surface through the opening.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Leach-proof microcapsule containing hydrophobic active molecules, wherein the microcapsule shell breaks upon exposure to a positive pressure drop across the inner and outer sides of the shell, 0<\u0394P=Pin\u2212Pout>5 bar, wherein Pin and Pout are the pressures in, respectively, out of the microcapsule, characterized in that, the microcapsule shell consists of a partially or fully alkylated organosilica compound, having an alkylation degree comprised between 2 and 100 mol. %, preferably between 5 and 20 mol. %, more preferably between 8 and 15 mol. %.
2. A microcapsule according to claim 1, wherein the microcapsule shell breaks upon exposure to a pressure drop across the inner and outer sides of the shell, \u0394P=Pin\u2212Pout, of not more than 1 bar, preferably, not more than 0.5 bar.
3. The microcapsule according to claim 2, characterized in that the hydrophobic active molecules are enclosed therein at a pressure higher than atmospheric by at least 0.5 bar, preferably by at least 1.0 bar.
4. The microcapsule according to claim 1, whereby the microcapsule is formed by sol-gel micro-encapsulation.
5. A microcapsule according to claim 1, characterized in that its shell has a hydrophilic-lipophilic balance of maximum 0.1.
6. A microcapsule according to claim 1, characterized in that the active molecules comprise at least one catalyst for use in active-catalyzed reactions, preferably benzoyl peroxide (BPO).
7. A process for preparing a leach-proof microcapsule according to claim 1, comprising the steps of:
(a) dissolving into a solvent (i) the hydrophobic active molecules and (ii) condensable microcapsule components, which comprise at least 2 wt %, preferably between 2 and 25 mol. % of an alkyl-modified silane molecule, and (iii) along with a fully hydrolysable silane; wherein the mol. % are defined with respect to the shell composition;
(b) emulsifying said solution to form an oil in water (OW) emulsion.
(c) treating the emulsion of step (b) with a condensation catalyst to form leach-proof organically modified silica microcapsules enclosing the hydrophobic active molecules.
8. A process according to claim 7, wherein the fully hydrolysable silane is an aminopropyl-modified silane, and wherein the OW emulsion is preferably prepared in the absence of any surfactant or mediating reagent.
9. The process according to claim 7, wherein the thus formed microcapsules are dispersed within a pressurized vessel in a mixture of monomersoligomers reactive with the active molecules enclosed in the microcapsules.
10. The process according to claim 7, whereby the microcapsules are prepared in a low boiling solvent, preferably liquefied petroleum gas (LPG).
11. A process according to claim 7 wherein the alkyl silicate molecule is an alkyl alkoxysilane, preferably methyl trimethoxysilane (MTMS), diethyl diethoxysilane. (DEDES), or triethyl methoxysilane (TEMS).
12. A foam precursor composition comprising microcapsules according to claim 1.
13. A pressurized can containing a foam precursor of composition according to claim 12, characterized in that the pressure in the container is such that the microcapsules shell is stable when stored in the can and breaks upon spraying the composition out of the can.
14. A pressurized can claim 13, containing a one component polyurethane foam precursor.