Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/22—Compounds of iron
  • C09C1/24—Oxides of iron
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D201/00—Coating compositions based on unspecified macromolecular compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82B—NANOSTRUCTURES FORMED BY MANIPULATION OF INDIVIDUAL ATOMS, MOLECULES, OR LIMITED COLLECTIONS OF ATOMS OR MOLECULES AS DISCRETE UNITS; MANUFACTURE OR TREATMENT THEREOF
  • B82B3/00—Manufacture or treatment of nanostructures by manipulation of individual atoms or molecules, or limited collections of atoms or molecules as discrete units
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/36—Compounds of titanium
  • C09C1/3607—Titanium dioxide
  • C09C1/3676—Treatment with macro-molecular organic compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
  • C09C3/10—Treatment with macromolecular organic compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2991—Coated
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2991—Coated
  • Y10T428/2998—Coated including synthetic resin or polymer

Definitions

• the invention relates to a method for coating substrate surfaces with LCST polymers, in particular the coating of pigment particles and in particular the irreversible coating of particulate and non-particulate substrate surfaces in general.
• LCST polymers are polymers that are soluble in a solvent at low temperatures and are separated from the solution as a separate phase when the temperature rises and the so-called LCST (lower critical solution temperature) is reached.
• Pigments are finely divided, particulate materials which, when mixed in a carrier or matrix material, influence or determine the coloring.
• the pigments are used in the smallest possible quantities for cost reasons. Due to interaction forces, agglomeration phenomena occur in particular when the pigment particles are incorporated into the carrier or matrix material, so that the number of particles available for coloring is reduced. Dissolving the agglomerates is sometimes very difficult - 2 -
• the pigment particles in particular of inorganic pigments, have a significantly higher density than the generally organic carrier or matrix material, so that sedimentation effects are observed when pigment dispersions are left to stand for a long time.
• the object of the present invention is to treat particles in such a way that they are stabilized as dispersed particles in liquid media, for example in paints.
• the particles are provided with a coating with LCST polymers, this being done by first dissolving an LCST polymer in a solvent at a temperature below LCST, mixing the particles with the solution thus obtained and then the temperature of the so mixture obtained until the onset of deposition of LCST polymer on the particle surfaces and possibly beyond.
• LCST polymers are particularly suitable for forming complete envelopes of particles without influencing the color of the particles themselves, since the LCST polymers are completely transparent in the visible range.
• particles which can be coated using the process according to the invention include:
• Pigments Titanium dioxide, iron oxide, zinc oxide, carbon black and Cu phthalocyanine particles;
• Fillers barium sulfate, talc, silicate, heavy spar particles;
• Nanoparticles iron oxide, titanium dioxide and silicon dioxide particles
• Microfibers glass, carbon, textile and polymer fibers.
• the particles due to the coating of the particles with LCST polymer, better compatibility of the particles or particles with the carrier medium or a matrix can be achieved, i. H. the particles can be adapted to aqueous or organic media regardless of their nature.
• the coating of the particles, in particular platelet-shaped particles of effect pigments, with LCST polymer also provides protection against mechanical damage in the case of shear loads, such as, for example, B. extrusion offers.
• the particles are preferably mixed into the solution of the LCST polymer as a dispersion, the same solvent as that of the LCST polymer solution preferably being used and the temperature of the dispersion being lowered below the LCST.
• the LCST polymer coatings are particularly preferably carried out as a complete coating of the (pigment) particles. - 4 -
• the layer thicknesses of the LCST polymer coatings are preferably -> 20 nm, more preferably> 25 n-ii and particularly preferably -> 50 nm.
• a particularly homogeneous, thick coating of surfaces is obtained if the material to be coated in the mixture with the LCST polymer solution is cyclically cooled one or more times and heated again after the initial heating to a temperature above the LCST.
• the coating process is particularly preferably carried out in such a way that, after the coating has been formed or when the coating is formed, the LCST polymers are immobilized on the surface of the substrates to be coated with it.
• crosslinking or anchoring can be achieved by suitable modifications of the polymer and / or the substrate, as a result of which chemical bonds are formed between the individual polymer chains (crosslinking) and / or between the substrate and the LCST polymer.
• suitable modification of the LCST polymers would be the introduction of a radical-crosslinkable group or of acid chloride or chloroformate groups, since this results in a reaction with OH, NH groups in the polymer (crosslinking) or with OH-, NH- Groups on the substrate surface (anchoring) is possible.
• Another possibility for immobilizing the LCST polymer layer is also in the thermodynamic sense, either by modifying the LCST polymer with groups that strongly interact with the substrate surface (ionic, polar, non-polar interactions) or by aiming for the lowest possible LCST of the polymer , - 5 -
• the polymer can also be grafted onto the surface by radicals (see T. Tsubokawa, A. Naitoh, J. Jpn. Soc. Color Mater. 72 (8) (1999) 475).
• a disadvantage of this technique is that the grafting-from process requires a functionalized surface that is not available or cannot be created for all substrates.
• the additional functionalization of the surface that may be required means an additional process step.
• the subsequent polyreaction is then to be carried out in the presence of the substrates, which in turn require very specific reaction conditions, such as temperature, solvent, etc., which often leads to at least partial flocculation of the substrate particles.
• very specific reaction conditions such as temperature, solvent, etc.
• the advantage of the present method lies in the general possibility of modifying surfaces of various types with polymer layers of adjustable thickness.
• the polymer is immobilized thermodynamically on the substrate surface, so that often - 6 -
• the LCST temperature is as low as possible below the operating temperature of the coated substrate, for example room temperature, and that the difference to the LCST is as large as possible, i.e. H.
• the temperature difference is preferably _> 10 ° C, more preferably at -> 15 ° C.
• the LCST is therefore preferably ⁇ .15, more preferably ⁇ . 10 ° C.
• fillers for plastics and lacquers which are in particle form and should be present in the end product as finely and evenly as possible.
• this method is suitable for improving the properties of these fillers, in that the filler particles are retained individually and do not form agglomerations and, moreover, can simultaneously be adapted to the plastic matrix or the coating medium or the coating carrier.
• the method described above is also suitable for coating non-particulate substrate surfaces with LCST polymer, whereby
• step (b) the solution obtained in step (a) is brought into contact with the substrate surface of the non-particulate substrate to be coated;
• Polymer is increased on the substrate surface or beyond.
• Another particularly important application of the present invention is in the coating of semiconductor wafers as a substrate with LCST polymers.
• the surface of the semiconductor wafers can be made hydrophobic in some areas or over the entire area with deposited LCST polymers, or else can be hydrophilized.
• the method according to the invention is therefore also suitable for achieving masks on the surfaces of semiconductor wafers by specifically depositing and immobilizing LCST polymers with a hydrophilic and / or hydrophobic character on the surface.
• the present invention thus relates not only to the process according to the invention, but also to pigments with a coating of an LCST polymer which have the abovementioned advantages.
• the scope of the invention also includes fillers which have an LCST polymer coating on their surface and in particular also semiconductor wafers which comprise a surface coating of immobilized LCST polymers.
• the pigments coated according to the invention can be used to produce binder-free pigment pastes with a carrier medium, preferably water or an organic solvent, which, owing to their freedom from binders, can be used universally in paints and varnishes. This eliminates the need to keep modified pigment pastes for paints and varnishes with different binder systems in stock.
• the binder-free pigment pastes according to the invention can be very easily mixed into the receiving media (paints, lacquers, plastics, etc.) because, owing to the LCST loading, - 8th -
• Layering prevents agglomeration of the pigment particles and the mixing process does not have to take this into account (there is no need for dispersing).
• the LCST coating according to the present invention - whether with particulate or non-particulate substrates - can serve as a protective layer for underlying coatings with UV stabilizers, chromophores or luminescent components.
• the coating with LCST polymers can also function as a modified particle surface on which the surface can be further functionalized.
• LCST polymers which are particularly suitable in connection with the present invention are, for example:
• PEO Polyethylene oxide
• PPO Polypropylene oxide
• Fig. 4 inventive effect of LCST polymers on the color strength of pigments.
• a PEO-PPO-PEO block copolymer with a molecular weight of 4,000 g / mol and an LCST value of 8 ° C (available from Aldrich) as an LCST polymer is distilled at approx. 5 ° C with a concentration of approx 10% by weight brought into solution. This solution is tempered to about 1 ° C.
• a 1 vol.% Dispersion of a titanium dioxide pigment (Kronos 2310 from Kronos International) is produced, weighing 6.8 g of the pigment with 400 g glass beads (diameter 3 mm) and 168 g of distilled water in a wide-necked flask made of polypropylene and weighing approx . 30 min. be dispersed in a Scandex shaker. The dispersion (pigment in water) is sieved off the glass beads and stirred further with a magnetic stirrer. The pigment dispersion is heated to about 1 ° C.
• the temperature-controlled polymer solution is added to the cooled pigment dispersion with continued stirring until the polymer - 10 -
• Mer fraction in the mixture is 5% by weight, based on the weight of pigment.
• the dispersion After a further 2 h of tempering to 1 ° C., the dispersion is warmed to room temperature (23 ° C.) and at this temperature for 15 min. held.
• the ESA method is a relatively new method for characterizing particle surfaces (R. W. O'Brien, D. W. Camron, W. N. Rowlands, J. Colloid Interface Sci. 173 (1985), 406):
• a high-frequency alternating electric field is applied to a particle dispersion, the particles execute a movement corresponding to the external electric field. Due to a density difference between the aqueous medium and the particles, a sound wave is generated at the phase boundaries of the aqueous medium, which however has a phase shift with respect to the excitation wave of the electric field.
• This phase shift, as well as the amplitude of this sound wave (ESA) is a direct function of the mobility ⁇ of the particles, whereby the dynamic mobility in turn depends on the excitation frequency and on particle properties such as zeta potential and particle size. If the dynamic mobility ⁇ of a particle which has an adsorbed polymer layer is now divided by the mobility ⁇ 0 of the particle without polymer coating, the result is - 11 -
• a 1 vol.% Titanium dioxide pigment dispersion is produced as described above.
• the dispersion is heated to 23 ° C. with stirring.
• 400 g of the dispersion are now weighed into the ESA measuring cell, with the addition of a saturated potassium nitrate solution (23 ° C.) and a one-molar KOH or a one-molar nitric acid solution (likewise 23 ° C.) to pH 8.5 and to a conductivity of 500 ⁇ S / cm.
• This is followed by the measurement of the dynamic mobility of the titanium dioxide particles without polymer coating at a 0.5 MHz excitation frequency.
• the dispersion is transferred to a tempered vessel and cooled to 2 ° C. with stirring.
• 100 ⁇ l of LCST polymer solution (10% by weight) are added and after 5 min. warmed to 23 ° C.
• the suspension is filled back into the ESA measuring cell and the dynamic mobility is measured again at 0.5 MHz.
• the relative mobility value ⁇ / ⁇ 0 obtained is then plotted against the amount of polymer added (FIG. 1, curve 1).
• Fe 2 0 3 pigments (Bayferrox 120 FS from Bayer AG) are coated with the same LCST polymer under the same conditions and the same quantitative ratios.
• the ⁇ / ⁇ 0 -reduced dynamic mobility of the coated pigment particles was determined analogously to Example 1. The data are shown graphically in Fig. 1 (curve 2). - 12 -
• Example 2 copper phthalocyanine blue pigment particles (Heliogen Blue from BASF AG) are coated with the same LCST polymer, the proportions for coating the particles being the same.
• the ⁇ / ⁇ 0 -reduced dynamic mobility of the coated pigment particles was determined analogously to Example 1. The data are shown graphically in FIG. 1 (curve 3).
• Organic pigments such as the Cu phthalocyanine blue used here generally show only weak interaction with strongly polar substances, such as, for example, owing to their relatively hydrophobic surface.
• the upper curve of FIG. 2 represents this case. It can be seen that the acrylate binder used as a negatively charged so-called polyelectrolyte shows no interaction with the likewise strongly negatively charged pigment particle surface of the copper phthalocyanine blue pigment, the reduced dynamic mobility ⁇ / ⁇ 0 , determined in water according to the ESA method at 23 ° C, remains constant.
• a 1 vol.% Pigment dispersion is prepared analogously to Example 1. This is tempered to 23 ° C and adjusted to a conductivity of 2,500 ⁇ S / cm and a pH of 8.5 by using KOH and KN0 3 solutions.
• a 20% by weight aqueous acrylic binder solution (Viacryl SC 323w / 70SBB, previous name: Resydrol WY 323, Vianova Resins, company Hoechst, Germany, also at pH 8 , 5 set) added and the relative mobility determined as a function of the amount of binder added (upper curve in FIG. 2).
• the 1 vol.% Pigment suspension is cooled to 2 ° C., 5 wt.% LCST polymer solution based on the pigment mass (10 wt.% Polymer solution in water) is added and after 30 min.
• a 20% by weight aqueous acrylate binder solution (likewise adjusted to pH 8.5) is titrated in and the relative mobility is determined as a function of the amount of binder added (lower curve in FIG. 2).
• the pigment particles are modified according to the invention with an LCST polymer (here the aforementioned PEO-PPO-PEO polymer) on their surface before being brought into contact with the acrylate binder, there is a much stronger interaction (lower curve of FIG. 2) and in order to - 14 -
• an LCST polymer here the aforementioned PEO-PPO-PEO polymer
• FIG. 3 shows the brightness values of a black blend (DIN 53 235, (1977), tests on standard color depth samples, standard color depths and color depth standards) of a lacquer layer pigmented with Ti0 2 , the Ti0 2 pigment particles being compared, as is conventional in industrial practice, with inorganic aftertreatment (Technical information, titanium dioxide pigments in industrial coatings, Kronos International, Leverkusen) and organic post-treatment (Technical information, titanium dioxide pigments in industrial coatings, Kronos International, Leverkusen) are used. The brightness value obtained in the inorganic aftertreatment was set to 100%.
• the titanium dioxide pigment treated with LCST polymers according to the invention shows a significantly increased brightness value Y. This is evidence of the better dispersion state of the titanium dioxide particles or, in other words, of a reduced degree of agglomeration. - 15 -
• the color strength measurements used in the present example show an improved dispersion state of the pigment particles (here Cu-phthalocyanine blue and iron oxide Bayferrox 120 FS) after a coating according to the invention (analogous to Example 4) with LCST polymer. Particularly drastic improvements can be seen in the iron oxide pigment (see FIG. 4).
• the relative color strength was measured here using white pigments (EN ISO 8781-1, (1995), methods for assessing the dispersion behavior, Part 1: Determination of the color strength development of colored pigments; DIN EN ISO 787-24, (1995) , General test methods for pigments and fillers, Part 24: Determination of the relative color strength of colored pigments and the relative tax capacity of white pigments - photometric methods).
• a semiconductor wafer with a 1 x 1 cm silicon dioxide surface is immersed in 3 ml of distilled water. It is cooled to 2 ° C. and 0.2 ml of a 10% by weight LCST polymer solution (for example PEO-PPO-PEO block copolymer, molecular weight approx. 4000, LCST approx. 8 ° C.) is added. After 2 hours at 2 ° C, the temperature is raised to 23 ° C within one hour. Then it is cooled again to 2 ° C, but only for a period of 10 min. and warmed to 23 ° C within an hour. This cooling and heating cycle is carried out three times in total. After the last cycle, the wafer remains in the liquid coating medium at 23 ° C for 24 hours and is then rinsed with distilled water. - 16th

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• Chemical & Material Sciences (AREA)
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• Crystallography & Structural Chemistry (AREA)
• Nanotechnology (AREA)
• Manufacturing & Machinery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
• Paints Or Removers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

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  • 2000-02-15 DE DE2000106538 patent/DE10006538C2/de not_active Expired - Lifetime
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  • 2001-02-15 WO PCT/EP2001/001670 patent/WO2001060926A1/de not_active Ceased
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  • 2001-02-15 AU AU2001242406A patent/AU2001242406A1/en not_active Abandoned
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