CA2329731A1 - Solid, meltable, thermohardeninig mass, its production and its use - Google Patents
Solid, meltable, thermohardeninig mass, its production and its use Download PDFInfo
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- CA2329731A1 CA2329731A1 CA002329731A CA2329731A CA2329731A1 CA 2329731 A1 CA2329731 A1 CA 2329731A1 CA 002329731 A CA002329731 A CA 002329731A CA 2329731 A CA2329731 A CA 2329731A CA 2329731 A1 CA2329731 A1 CA 2329731A1
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- 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
- C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
- C09D183/04—Polysiloxanes
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L85/00—Compositions of macromolecular compounds obtained by reactions forming a linkage in the main chain of the macromolecule containing atoms other than silicon, sulfur, nitrogen, oxygen and carbon; Compositions of derivatives of such polymers
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- 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
- C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
- C09D183/14—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms
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- 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
- C09D185/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing atoms other than silicon, sulfur, nitrogen, oxygen, and carbon; Coating compositions based on derivatives of such polymers
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Abstract
The invention relates to a solid, meltable and thermohardening mass, comprising condensates (K) derived from at least one hydrolyzable silane and possibly one or more hydrolyzable metal compounds. Groups (A) positioned on the central atoms (M) of the condensates (K) permit the further condensation of the condensates. At least 70 % of the central atoms (M) present one or more non-hydrolyzable organic groups (R) linked to same, a part of which can be substituted by complex-forming species coordinated with the central atoms (M).
At temperatures of between 50 and 200 ~C the condensates (K) have a minimum viscosity of between 10 mPa.s and 150 Pa.s. The above mass is suitable, for example, for a powder coating for coating metal, plastic, glass and ceramic substrates.
At temperatures of between 50 and 200 ~C the condensates (K) have a minimum viscosity of between 10 mPa.s and 150 Pa.s. The above mass is suitable, for example, for a powder coating for coating metal, plastic, glass and ceramic substrates.
Description
SOLID, MELTABLE, THERM08ARDENING MASS, ITS PRODUCTION
AND ITS USE
The present invention relates to a solid, meltable and heat-curable organic-inorganic composition, to its preparation and to its use.
The use of powder coating materials has become widely established, since in contrast to coating systems applied as solutions the said materials release significantly lower amounts of volatile constituents and may therefore be used in a way which is substantially more compatible with the environment. The powder coating materials generally comprise thermoplastic (organic) filled polymer particles which may be applied to a substrate surface and which then flow out on heating, so producing an impervious coat. A
disadvantage of such powder coating materials, however, is that for many applications they are unsuitable or of only limited suitability owing to the properties of their constituent polymers. One of these disadvantageous properties is a gradual softening behaviour, which permits a flowable phase only at relatively high temperatures, and, owing to the high viscosity which prevails even at these high temperatures, the need to apply thick layers (not less than from 80 to 100 ~,m). Moreover, a feature of thermoplastic materials is their relatively poor mechanical properties, especially as regards abrasion resistance and scratch resistance.
Reactive systems, especially those which feature the structure of an inorganic network (examples being organic-inorganic composite materials produced by sol-gel techniques), although possessing excellent mechanical properties and high abrasion resistance, are not thermoplastic, since the inorganic network is built up spontaneously and even at room temperature leads to such high degrees of condensation that thermoplasticity is unable to occur.
AND ITS USE
The present invention relates to a solid, meltable and heat-curable organic-inorganic composition, to its preparation and to its use.
The use of powder coating materials has become widely established, since in contrast to coating systems applied as solutions the said materials release significantly lower amounts of volatile constituents and may therefore be used in a way which is substantially more compatible with the environment. The powder coating materials generally comprise thermoplastic (organic) filled polymer particles which may be applied to a substrate surface and which then flow out on heating, so producing an impervious coat. A
disadvantage of such powder coating materials, however, is that for many applications they are unsuitable or of only limited suitability owing to the properties of their constituent polymers. One of these disadvantageous properties is a gradual softening behaviour, which permits a flowable phase only at relatively high temperatures, and, owing to the high viscosity which prevails even at these high temperatures, the need to apply thick layers (not less than from 80 to 100 ~,m). Moreover, a feature of thermoplastic materials is their relatively poor mechanical properties, especially as regards abrasion resistance and scratch resistance.
Reactive systems, especially those which feature the structure of an inorganic network (examples being organic-inorganic composite materials produced by sol-gel techniques), although possessing excellent mechanical properties and high abrasion resistance, are not thermoplastic, since the inorganic network is built up spontaneously and even at room temperature leads to such high degrees of condensation that thermoplasticity is unable to occur.
It has now surprisingly been found that it is possible to stop the formation of (hetero)polycondensates based on hydrolysable silanes and, if desired, other hydrolysable (metal) compounds at such a low degree of crosslinking (degree of condensation) that the condensates in question are produced as meltable solids, which may be melted to a low-viscosity coating and subsequently cured thermally (and also, if appropriate, photochemically) by further condensation and, if appropriate, by the reaction of organic groups that are present. The arrest of the formation of the (hetero)polycondensates at a low degree of crosslinking may be brought about by a raft of measures, which are elucidated in more detail below.
The present invention provides a solid, meltable and heat-curable composition which comprises condensates K derived from at least one hydrolysable silane and, if desired, from one or more hydrolysable metal compounds, (1) central atoms M of the condensates K bearing groups A which permit further condensation of the condensates, (2) at least 70% of the central atoms M having one or more nonhydrolysable organic groups R
attached thereto, some of which may be replaced by complex-forming species coordinated with the central atoms M, and (3) the condensates K passing through a viscosity minimum in the range from 10 mPa.s to 150 Pa.s within the temperature range from 50 to 200°C.
The above composition is suitable, for example, as a powder coating material for the coating of substrates, for example for producing an abrasion resistant and anticorrosive coating on metals, for example as a (transparent) topcoat (over a polyurethane basecoat, for example) in the automotive industry.
In the text below, the present invention is elucidated in more detail with reference to preferred embodiments thereof.
The monomeric hydrolysable compounds on which the condensates K are based preferably comprise one or more hydrolysable silanes, especially silanes of the general formula RnSlXq_nr in which R is an organic group defined in more detail below, the groups X, which may be identical or different and are preferably identical, are hydrolysable radicals, and n may adopt the value 1, 2 or 3, preferably 1 or 2 and with particular preference 1. The radicals X are preferably selected from halogen atoms (especially chlorine and bromine), alkoxy groups, alkylcarbonyl groups and acyloxy groups, particular preference being given to alkoxy groups, especially C1-q alkoxy groups such as methoxy and ethoxy.
Among the hydrolysable silanes used, it is also possible for a small fraction (preferably less than 5 mol.°s, based on all the monomeric hydrolysable compounds used) to comprise silanes of the above formula in which n is 0.
The hydrolysable metal compounds which may be used in addition to the at least one hydrolysable silane are preferably those which derive from metals of main groups IIIa and IVa and of transition groups IVb, Vb and VIb of the Periodic Table, particular preference being given to compounds of aluminium, titanium and zirconium. The hydrolysable compounds of the last-mentioned elements, taking into consideration their substantially higher reactivity in hydrolysis and condensation than that of the silicon compounds, are preferably complex compounds, the subject of complexing agents that may be used being addressed in more detail later on below. If corresponding compounds which are more active are to be used, examples being the alkoxides of Al, Ti and/or Zr, appropriate measures must be taken to ensure that the high reactivity of these compounds does not lead to problems in setting the desired degree of condensation and/or the desired viscosity pattern, for example by working at a low temperature (e.g. 0°C or below) and/or using the compounds in small amounts and/or in high dilution.
The present invention provides a solid, meltable and heat-curable composition which comprises condensates K derived from at least one hydrolysable silane and, if desired, from one or more hydrolysable metal compounds, (1) central atoms M of the condensates K bearing groups A which permit further condensation of the condensates, (2) at least 70% of the central atoms M having one or more nonhydrolysable organic groups R
attached thereto, some of which may be replaced by complex-forming species coordinated with the central atoms M, and (3) the condensates K passing through a viscosity minimum in the range from 10 mPa.s to 150 Pa.s within the temperature range from 50 to 200°C.
The above composition is suitable, for example, as a powder coating material for the coating of substrates, for example for producing an abrasion resistant and anticorrosive coating on metals, for example as a (transparent) topcoat (over a polyurethane basecoat, for example) in the automotive industry.
In the text below, the present invention is elucidated in more detail with reference to preferred embodiments thereof.
The monomeric hydrolysable compounds on which the condensates K are based preferably comprise one or more hydrolysable silanes, especially silanes of the general formula RnSlXq_nr in which R is an organic group defined in more detail below, the groups X, which may be identical or different and are preferably identical, are hydrolysable radicals, and n may adopt the value 1, 2 or 3, preferably 1 or 2 and with particular preference 1. The radicals X are preferably selected from halogen atoms (especially chlorine and bromine), alkoxy groups, alkylcarbonyl groups and acyloxy groups, particular preference being given to alkoxy groups, especially C1-q alkoxy groups such as methoxy and ethoxy.
Among the hydrolysable silanes used, it is also possible for a small fraction (preferably less than 5 mol.°s, based on all the monomeric hydrolysable compounds used) to comprise silanes of the above formula in which n is 0.
The hydrolysable metal compounds which may be used in addition to the at least one hydrolysable silane are preferably those which derive from metals of main groups IIIa and IVa and of transition groups IVb, Vb and VIb of the Periodic Table, particular preference being given to compounds of aluminium, titanium and zirconium. The hydrolysable compounds of the last-mentioned elements, taking into consideration their substantially higher reactivity in hydrolysis and condensation than that of the silicon compounds, are preferably complex compounds, the subject of complexing agents that may be used being addressed in more detail later on below. If corresponding compounds which are more active are to be used, examples being the alkoxides of Al, Ti and/or Zr, appropriate measures must be taken to ensure that the high reactivity of these compounds does not lead to problems in setting the desired degree of condensation and/or the desired viscosity pattern, for example by working at a low temperature (e.g. 0°C or below) and/or using the compounds in small amounts and/or in high dilution.
In the condensates K that are used in the composition of the invention, preferably at least 75, in particular at least 85 and with particular preference at least 95% (including 100%) of the central atoms M are silicon atoms, the remainder to 100%
originating from the other hydrolysable metal compounds used, especially compounds of A1, Ti and Zr.
Preferred condensates K comprise at least 5, preferably at least 10 and in particular at least 20 central atoms M. The number of central atoms M may, for example, be up to 300, preferably up to 200 and in particular up to 150. The central atoms M are preferably connected via oxygen bridges. Moreover, it is preferred for at least 70 and preferably at least 80% of the central atoms M to have at least one organic group R (not replaced by complex-forming species), all of the remainder of the central atoms M preferably being coordinated with complex-forming species.
Finally, it is also preferred for the numerical ratio x of the central atoms M present in the condensates K to the sum of the groups A which these central atoms bear and which permit further condensation (inorganic crosslinking) to be in the range from 1:2 to 20:1, in particular from l:l to 10:1, with particular preference from 2:1 to 5:1. These groups A on the central atoms M comprise preferably hydroxyl, alkoxy, aryloxy, acyloxy (e. g. acetoxy), enoxy or oxime groups. Preferably, at least 80% of the binding sites, which permit further condensation, on the central atoms M are groups A (e. g. hydroxyl groups), with the remaining binding sites being blocked by complex-forming species. Suitable complexing agents are, for example, chelate formers such as (3-diketones (e. g. acetylacetone), (3-keto esters (e. g. acetyl acetate), organic acids (e. g. acetic acid, propionic acid, acrylic acid, methacrylic acid), a-hydroxy carboxylic acids (e.g. a-hydroxypropionic acid), or else inorganic complex-forming species such as, for example, fluoride, thiocyanate, cyanate and cyanide ions and also ammonia and quaternary ammonium salts such as, for example, tetraalkylammonium salts (chlorides, bromides, hydroxides, etc.), examples being tetramethylammonium and tetrahexylammonium salts.
In addition to the abovementioned central atoms M, which are derived preferably from Si, A1, Ti and Zr, the condensates K may also comprise end groups comprising alkali metal and/or alkaline earth metal atoms.
Various measures, and combinations thereof, may be used to promote the formation of the condensates K, which are used in the composition of the invention, with the desired viscosity behaviour, a relatively low degree of condensation and a relatively low ratio of central atoms to binding sites capable of further condensation. For example, as already mentioned above, it is possible to conduct the polycondensation at relatively low temperatures and/or with high dilution of the (monomeric) hydrolysable starting compounds and/or with sharply curtailed condensation times. In accordance with the invention, however, preference is given to other measures, especially the (concomitant) use of hydrolysable starting compounds whose condensation at room temperature is hindered or prevented by sterically (more) bulky organic groups R
but is able to take place readily at the elevated temperatures required to melt the composition of the invention (and at temperatures above these). A further measure which is preferred in accordance with the invention, and which may be used alternatively or in addition to the measures already mentioned, is the incorporation into the composition of the invention of one or more substances which at the elevated temperatures required to melt the composition (or even at higher temperatures) release a catalyst for the condensation of the remaining condensable binding sites (especially an acid or base).
Finally, a further preferred measure of the invention, which may likewise be used alternatively or in addition to the other measures, comprises using hydrolysable starting compounds with organic groups R
which at the elevated temperatures required to melt the composition (or higher temperatures) are able to enter into a reaction (catalysed or otherwise) with identical or different reactive organic groups R that leads to an organic crosslinking of the existing condensates. In this case it is possible, for example, to incorporate into the composition of the invention a thermal addition-polymerization catalyst and/or condensation-polymerization. catalyst which is activated only at the temperatures required to melt the composition of the invention (or at temperatures above these). In this way, besides the inorganic crosslinking of the condensates K (i.e. further condensation) there may also be an additional organic crosslinking of these condensates. It is of course also possible to carry out such an organic crosslinking photochemically (preferably with added photoinitiator and with UV
irradiation) and in addition to thermal curing (for example, subsequently thereto).
The measures set out above are elucidated in more detail below.
Groups suitable for the steric hindrance or prevention of the condensation of hydrolysed species at room temperature or at a temperature which is necessary for the later required removal of volatile constituents from the reaction mixture, with formation of a solid mass, are bulky organic groups R, such as, for example, unsubstituted or substituted C6-to aryl groups and (cyclo)aliphatic groups which produce a steric hindrance corresponding at least to that of an isopropyl group. Groups R which are preferred for this purpose in accordance with the invention are (unsubstituted or substituted) phenyl groups.
Accordingly, a preferred group of hydrolysable starting compounds for preparing the condensates K is that of the hydrolysable phenylsilanes and diphenylsilanes, examples being phenyltrimethoxysilane and phenyl-_ 7 _ triethoxysilane and the corresponding diphenyl compounds, and also the compounds which have already undergone partial or complete hydrolysis, such as diphenylsilanediol, for example. Additionally or alternatively to the provision of sterically bulky groups R (especially on the silicon atom) it is also possible to provide, in the starting compounds, thermally labile organic groups R, for example ethyl groups and vinyl groups, which decompose at elevated temperatures and so clear the way for a (direct) linking of the central atoms to which they were attached. Accordingly, a further preferred group of starting compounds for the condensates K used in accordance with the invention consists of silanes containing, for example, ethyl groups or vinyl groups, examples being ethyltri(m)ethoxysilane and vinyltri(m)ethoxysilane.
The abovementioned organic crosslinking of the condensates used in accordance with the invention may be brought about, for example, by starting from hydrolysable starting compounds (preferably silicon compounds) which possess organic radicals R which enter into a (chain) reaction at relatively high temperatures, either by themselves or with the aid of a catalyst which is activated at these relatively high temperatures. In this context mention might be made, in particular, of epoxy-containing groups R and of groups R having a reactive carbon-carbon multiple bond (especially double bond). Specific and preferred examples of such radicals R are glycidyloxyalkyl and (meth)acryloyloxyalkyl radicals, which preferably are attached to a silicon atom and preferably have 1 to 6 carbon atoms in the alkyl radical, especially glycidyloxypropyl and methacryloyloxypropyl groups.
Accordingly, a further group of hydrolysable starting compounds used with preference consists of glycidyloxyalkyltri(m)ethoxysilane and methacryl-oyloxyalkyltri(m)ethoxysilane. It is of course also possible to use starting compounds having different groups R which are able to react with one another, such as, for example, groups R with a carbon-carbon multiple bond and groups R with an SH group (which at elevated temperatures arid, if appropriate, with catalysis are able to add onto the carbon-carbon multiple bond) or groups R with an epoxide ring and groups R with an amino group. Very generally, it is possible to use groups R, or combinations of groups R, which at elevated temperatures are able to enter into a catalysed or uncatalysed addition-polymerization reaction or condensation-polymerization reaction.
Addition-polymerization reactions are preferred since unlike condensation reactions they do not lead to any by-products. In such a case it may be advisable to carry out separate preparation of polycondensates containing groups R that are reactive with one another, and to combine the separately prepared polycondensates with one another only as solids.
As already elucidated in more detail above, a further measure for setting the desired viscosity pattern and/or for inhibiting further condensation at room temperature or slightly elevated temperature of the condensates K that are used comprises blocking condensable sites on the central atoms by complex forming species, the corresponding complexes being removed at the temperatures required to melt the composition of the invention (or at temperatures above these) and so clearing the way for further condensation. Complexing agents suitable for this purpose have already been indicated above. Complexing agents of this kind are used preferably in combination with metal compounds which differ (in terms of the central atom) from the hydrolysable silanes, but may also be used in the form of complexed silanes.
One possibility for promoting the further condensation at elevated or high temperatures of the condensates K that are used in accordance with the invention, and by this means setting the desired viscosity behaviour, comprises incorporating into the _ g _ composition of the invention one or more substances which at elevated temperatures release and/or give off species which are catalytically active with respect to the condensation. Examples of such catalytically active species are protons, hydroxide ions, fluoride ions and the like. For example, at temperatures above 160°C, tetraalkylammonium salts release tertiary amines, which are likewise catalytically active. As already mentioned, the same principle may be applied to the organic crosslinking as well, namely by incorporating into the composition of the invention, for example, a thermally activatable free-radical initiator, such as a peroxide or an azo compound, for example, which then initiates the thermal addition polymerization of corresponding organic groups R.
In addition to the above components that are essential and/or preferred for the preparation of the composition of the invention, it is of course also possible to add to the said composition, or to incorporate into it, other components in order, in addition, to achieve other desirable properties. For example, it is possible to use, as some of the starting compounds to be hydrolysed, those containing fully or partly fluorinated radicals R, in order to obtain coatings having hydrophobic and oleophobic properties.
In this case, appropriate starting compounds that might be mentioned include, for example, trialkoxysilanes having a 2- (preferably C2_12) perfluoroalkylethyl radical. Another possibility for introducing fluorine atoms into the composition of the invention is, for example, to use perfluorocarboxylic acids (for example, as complex-forming species) or fluorinated organic copolymers (see below).
If an organic crosslinking of the condensates K
used in the composition of the invention is intended with the aid of groups R capable of an addition polymerization or condensation-polymerization reaction at elevated temperatures (or on irradiation), it may prove to be useful to incorporate into the composition of the invention, as well, corresponding purely organic monomers, which are preferably solid at room temperature and have the capacity to be included in the addition-polymerization and/or condensation-s polymerization reaction of the corresponding organic groups R, examples being caprolactam, malefic acid and pyromellitic dianhydride. The same also relates to the possible incorporation of polymers into the composition of the invention, in which context mention might be made, for example, of silane-functionalized polyesters and other powder coating substances.
The composition of the invention may also comprise customary fillers. Particular preference is given to the incorporation of nanoparticulate oxide powders with or without surface modification (particle size preferably up to 200 nm, in particular up to 100 nm), such as those, for example, of silica, alumina (especially boehmite) and zirconium oxide. These nanoparticulate oxide powders may be incorporated into the composition of the invention either during the preparation of the condensates and/or after their preparation.
Of course, the composition of the invention may also comprise other additives customary for powder coating materials, such as levelling additives, brighteners, dyes, pigments and the like. Preferably, however, at least 50~ by weight and in particular at least 80°s by weight of the composition of the invention comprises the above condensates K. Fillers and/or the abovementioned nanoparticulate oxide powders are used preferably in an amount of up to 25°s by weight, in particular up to 15% by weight.
The composition of the invention may be prepared by techniques familiar to the person skilled in this art, an example being the sol-gel process. This is followed by removal of the volatile auxiliaries (e.g. organic solvents and water) used in the course of the preparation process and of the volatile materials formed during the process (e.g. alcohols in the case of - ~. 1 -the hydrolysis of alkoxides). This removal takes place likewise with the aid of common techniques and equipment, such as rotary evaporators, thin-film evaporators, spray dryers and the like, for example.
Following removal of the volatile constituents to give a solid mass, this mass may be processed further, if desired, to an appropriate particle size or to an appropriate particle size distribution, by grinding, sieving and the like, for example.
The use of the mass obtained in this way (powder coating material) for the coating of substrates, especially those of metals, plastics, glass and ceramic, may likewise take place with the aid of known techniques, but preferably by means of electrostatic powder coating.
The examples which follow serve to illustrate the present invention further. In the context of the invention, the viscosity of the condensates K is measured in accordance with the standards DIN 1342 T1 and T2 and DIN 53018 T1 using a rotational viscometer ("Rheolab MC 20" from Physica Mel~technik GmbH & Co KG, D-70567 Stuttgart) with plate and cone geometry in accordance with DIN 53018 T1 (cone angle 2°). Two measurement systems are employed:
System 1: Cone radius 1.25 cm; can be used for measuring viscosities ranging from 0.5 to 3200 Pa. s;
System 2: Cone radius 3.75 cm; can be used for measuring viscosities ranging from 0.02 to 120 Pa. s.
System 2 allows more precise measurements than system 1 in the viscosity range below 1 Pa.s. In the region of overlap between the two measuring systems, identical condensates at identical temperature give identical viscosity values. The viscosity is measured in all cases at a shear rate of 1.05 rad/s and a heating rate of 2 K/min in the temperature range from 50 to 200°C.
Example 1 48.87 g (0.2 mol) of diphenyldimethoxysilane were added to 14.82 g (0.1 mol) of vinyl-trimethoxysilane. 37.8 g of 0.1 N HC1 were added dropwise to the mixture with vigorous stirring. Gentle heating occurred. Following the addition, stirring was continued at room temperature for 1 h. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about 5 - 6 mbar for 1 h. This gave a free-flowing powder having a viscosity minimum of from 0.02 to 0.03 Pa.s and a melting temperature of 172°C.
After milling (Red Devil, from Erichsen) the powder was applied electrostatically (manual spray gun, from 4Vagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)).
The coated A1 panels were cured in a convection oven at 170°C for 30 minutes. The resultant smooth, transparent coating of 35 ~m in thickness exhibited quasi-thermosetting behaviour, as demonstrated by DSC
analyses (DSC 200, from Netsch).
Example 2 73.3 g (0.3 mol) of diphenyldimethoxysilane were added to 24.8 g (0.1 mol) of methacryl-oyloxypropyltrimethoxysilane (MPTS). A mixture of 1.2 g (0.02 mol) of 'y-A10(OH) and 73 g of O.1 N HC1 was added dropwise to the mixture with vigorous stirring. Marked heating occurred. The dispersal of the y-A10(OH) in the aqueous medium was carried out by first introducing the aqueous HCl solution, then slowly adding the y-A10(OH) (Disperal~ Sol P3, from Condea) with vigorous stirring, and finally treating the suspension with ultrasound at room temperature for about 20 minutes.
Following the addition of the aqueous y-A10(OH) solution, stirring was continued at room temperature for 15 minutes. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about 5 - 6 mbar for 1 hour. This gave a non free-flowing powder having a viscosity minimum of from 0.02 to 0.04 Pa.s and a melting temperature of 147°C.
The powder was applied uniformly to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)) and cured in a convection oven at 170°C for 30 minutes.
The resultant transparent coating exhibited quasi-thermosetting behaviour, as demonstrated by DSC
analyses.
Example 3 61.09 g (0.25 mol) of diphenyldimethoxysilane were added to 14.82 g (0.1 mol) of vinyl trimethoxysilane. A mixture of 1.2 g (0.0047 mol) of N
trimethoxysilylpropyl-N,N,N-trimethylammonium chloride and 45.5 g of 0.1 N HC1 were added dropwise to the mixture with vigorous stirring. Gentle heating occurred. Following the addition, stirring was continued at room temperature for 1 h. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about 5 - 6 mbar for 1 h. This gave a free-flowing powder having a viscosity minimum of from 0 . 3 to 1 . 8 Pa. s and a melting temperature of 90°C.
The powder was applied uniformly to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)) and cured in a convection oven at 170°C for 30 minutes, as demonstrated by DSC analyses.
Example 4 A 50 ml round-bottomed flask was charged with 0.015 mol of a technical-grade solution of zirconium tetra-n-propoxide in n-propanol (amount of Zr[OPr]9, determined by gravimetry: 77.3% by weight). 0.015 mol of methacrylic acid was added slowly dropwise to the zirconium tetra-n-propoxide, with stirring, during which a slightly exothermic reaction occurred. The reaction mixture was stirred in the closed flask for 30 minutes, protected from the light, after which it was processed further directly.
48.87 g (0.2 mol) of diphenyldimethoxysilane were added to 14.82 g (0.1 mol) of vinyl trimethoxysi:Lane. The zirconium tetra-n propoxide/methacrylic acid mixture prepared as described above was added dropwise to this mixture with stirring.
40 g of 0.1 N HC1 were added dropwise with vigorous stirring to the resultant reaction mixture.
Gentle heating occurred. Following the addition, stirring was continued at room temperature for 1 h, with protection from the light. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about 5 -6 mbar for 1 h. This gave a free-flowing powder having a viscosity minimum of from 0.03 to 0.1 Pa.s and a melting temperature of 93°C.
The powder was intimately mixed with 2~ by weight of benzoin (based on the finished powder) and, following a grinding operation, was applied uniformly to aluminium. panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)) and cured in a convection oven at 170°C for 30 minutes, as demonstrated by DSC analyses.
Example 5 39.66 g (0.2 mol) of phenyltrimethoxysilane, 14.82 g (0.1 mol) of vinyltrimethoxysilane and 97.74 g (0.4 mol) of diphenyldimethoxysilane were weighed out in the stated sequence . 91 . 8 g of 0 . 1 N HC1 were added dropwise to the mixture with vigorous stirring. Gentle heating occurred. Following the addition, stirring was continued at room temperature for lh. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about - 6 mbar for 1 h. This gave a free-flowing powder having a viscosity minimum of from 0.1 to 0.3 Pa.s and a melting temperature of 100°C.
The powder was applied uniformly to aluminium 5 panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)) and cured in a convection oven at 160°C for 30 minutes, as demonstrated by DSC analyses.
Example 6 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [(3-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows:
0.36 g (0.006 mol) of y-A10(OH) was added in portions with vigorous stirring to 18 g of 0.1 N HC1.
Subsequently, 11.61 g (0.1 mol) of malefic acid were added in portions with vigorous stirring to the clear solution formE:d. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of minutes. Following the addition, stirring was 25 continued at room temperature for 4 h. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -20 mbar for 0.5 h, dried under reduced pressure 30 (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of from 4.3 to 8.6 Pa.s and a melting temperature of 90°C, an average density of 1.29 g/cm3 and a particle size distribution of 20 - 100 N,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSC analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 7 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [(3-(3,4-epoxy-cyclohexyl)ethyl]trimethoxysilane (ETMS). To this solution were added in portions 26.88 g (0.025 mol) of finely mortared glycidyl-endcapped poly(bisphenol A-co-epichlorohydrin) (Mn approximately 1075). After about 15 minutes, a clear solution had formed (mixture A). A
mixture B was prepared in parallel as follows : 11. 61 g (0.1 mol) of malefic acid were added in portions with vigorous stirring to 18 g of 0.1 N HCl. Following the addition, stirring was continued at room temperature for 10 minutes so that a transparent mixture formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of minutes. Following the addition, stirring was continued at room temperature for 4 h. As the reaction 25 time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and 30 subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of 10 Pa.s and a melting temperature of 93°C, an average density of 1.29 g/cm3 and a particle size distribution of 20 - 100 Vim. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSC analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 8 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24. 63 g (0.1 mol) of [(3- (3, 4-epoXy-cyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A
mixture B was prepared in parallel as follows: 11.61 g (0.1 mol) of malefic acid were added in portions to 18 g of 0.1 N HC1. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-f:Lowing powder having a viscosity minimum of 13.3 Pa.s and a melting temperature of 102°C, an average density of 1.29 g/cm3 and a particle size distribution of 20 - 100 Vim. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSC analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 9 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS), 5.44 g (0.015 mol) of bis(3-glycidyloxy-propyl)tetramethyldisiloxane (BGTS), 6.54 g (0.03 mol) of pyromellitic dianhydride and up to 3.00 g (0.05 mol) of Si02 (10.00 g of Organosol~ (silica sol in 2-propanol, Si02 content in the sol - 29. 9%, from Bayer) ) were added at room temperature with vigorous stirring to 24.63 q (0.01 mol) of [(3-(3,4-epoxycyclohexyl)ethyl] trimethoxy-silane (ETMS).
With vigorous stirring and ice cooling, 18 g of 0.1 N HC1 was added dropwise to the white suspension formed over the course of 5 minutes. Following the addition, stirring was continued at room temperature for 14 h. With increasing reaction time, the suspension initially present turned into a transparent sol. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 - 20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of from 80 to 95 Pa.s and a melting temperature in the range from 95 to 105°C, an average density of 1.26 g/cm3 and a particle size distribution of 10 - 100 ~,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco0, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at from 120 to 150°C for 20 to 120 minutes. The resultant - 18a -coherent, transparent coating of 10 - 20 ~m in thickness possesses good adhesion (Gt 0/l, TT 0/1).
Example 10 24.44 g (0.1 mol) of diphenyldimethoxysilane 5 (DPDMS), 2.3 g (0.01 mol) of dodecanedicarboxylic acid (DD) and 'up to 6 g (0.1 mol) of Si02 (20.00 g of Organosol~ (silica sol in 2-propanol, Si02 content in the sol - 29.9%, from Bayer)) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [(3-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows: 11.61 g (0.1 mol) of malefic acid were added in portions with vigorous stirring to the clear solution formed. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. With increasing reaction time, the suspension initially present turned into a clear sol. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 - 20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of from 6.5 to 10 Pa.s and a melting temperature in the range from 90 to 100°C, an average density of 1.29 g/cm3 and a particle size distribution of 10 - 100 ~,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at from 120 to 150°C for from 20 to 120 minutes. The resultant coherent, transparent coating of 10 - 25 ~m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 11 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) and up to 3.00 g (0.05 mol) of Si02 (10.00 g of Organosol~ (silica sol in 2-propanol, Si02 content in the sol - 29.9%, from Bayer)) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [~3-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows: 11.61 g (0.1 mol) of malefic acid were added in portions with vigorous stirring to the clear solution formed. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. With increasing reaction time, the suspension initially present turned into a clear sol. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 - 20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of 8.4 Pa.s and a melting temperature in the range from 85 to 95°C, an average density of 1.29 g/cm3 and a particle size distribution of 10 - 100 ~,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at from 120 to 150°C for from 20 to 120 minutes. The resultant coherent, transparent coating were 10 - 25 ~m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 12 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [(3-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows:
0.36 g (0.006 mol) of y-A10(OH) was added in portions with vigorous stirring to 18 g of 0.1 N HC1.
Subsequently, 11.61 g (0.1 mol) of malefic acid were v added in portions with vigorous stirring to the clear solution formed. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. With increasing reaction time, the suspension initially present turned into a white, solid mass . The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This 15 gave a free-flowing powder having a viscosity minimum of from 4.3 to 8.6 Pa.s and a melting temperature of 90°C, an average density of 1.29 g/cm3 and a particle size distribution of 20 - 100 ~tm. Following the melting operation, the powder has thermosetting properties, as 20 demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)).
The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion to the substrate (Gt 0/1, TT 0/1) .
Example 13 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) and 6.54 g (0.03 mol) of pyromellitic - 21a -dianhydride were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [~3-(3,4-epoxycyclo-hexyl)ethyl]trimethoxysilane (ETMS).
With vigorous stirring and ice cooling, 18 g of 0.1 5 N HCl was added dropwise to the white suspension formed over the course of 5 minutes. Following the addition, stirring was continued at room temperature for 14 h. With increasing reaction time, the suspension initially present turned into a transparent sol. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 - 20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having an average density of 1.26 g/cm3 and a particle size distribution of 10 - 100 Nxn. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at from 120 to 150°C for 20 to 120 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 14 12.22 g (0.05 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [~i-(3,4 epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows:
5.8 g (0.05 mol) of malefic acid were added in portions with vigorous stirring to the clear solution formed.
Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. With increasing reaction time, the suspension initially present turned into a white, solid mass . The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having an average density of 1.29 g/cm3 and a particle size distribution of 20 -100 ~,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM
analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)).
The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 15 A mixture of 25.3 ml of glycidyloxypropyltrimethoxysilane, 80.3 ml of phenyltrimethoxysilane, 16.8 ml of silica sol 300-30 (300, from Bayer), 10 ml of water and 0.52 ml of hydrochloric acid was stirred intensively until the temperature of the mixture had risen, owing to the heat of reaction, to about 45 to 50°C. Immediately thereafter, the mixture was concentrated on a rotary evaporator at a bath temperature of approximately 50°C.
When solvent no longer went over, a viscous material had formed which on cooling could be pulverized. When the powder was heated on a hotplate at 200°C, the powder changed to a low-viscosity melt, with foaming, and slowly solidified over the course of from 10 to 15 minutes. A transparent, highly glossy coat was formed.
Example 16 27.6 ml of phenyltrimethoxysilane, 17 g of diphenylsilanediol, 14 g of tetramethylammonium hydroxide x 5 H20 and 10 g of H20 was stirred intensively until the mixture had warmed, owing to the heat of reaction, to about 45 to 50°C. Drying on a rotary evaporator gave a powder which formed a very low-viscosity melt and hardened within 1 to 2 hours at 200°C (decomposition of the tetramethylammonium hydroxide).
originating from the other hydrolysable metal compounds used, especially compounds of A1, Ti and Zr.
Preferred condensates K comprise at least 5, preferably at least 10 and in particular at least 20 central atoms M. The number of central atoms M may, for example, be up to 300, preferably up to 200 and in particular up to 150. The central atoms M are preferably connected via oxygen bridges. Moreover, it is preferred for at least 70 and preferably at least 80% of the central atoms M to have at least one organic group R (not replaced by complex-forming species), all of the remainder of the central atoms M preferably being coordinated with complex-forming species.
Finally, it is also preferred for the numerical ratio x of the central atoms M present in the condensates K to the sum of the groups A which these central atoms bear and which permit further condensation (inorganic crosslinking) to be in the range from 1:2 to 20:1, in particular from l:l to 10:1, with particular preference from 2:1 to 5:1. These groups A on the central atoms M comprise preferably hydroxyl, alkoxy, aryloxy, acyloxy (e. g. acetoxy), enoxy or oxime groups. Preferably, at least 80% of the binding sites, which permit further condensation, on the central atoms M are groups A (e. g. hydroxyl groups), with the remaining binding sites being blocked by complex-forming species. Suitable complexing agents are, for example, chelate formers such as (3-diketones (e. g. acetylacetone), (3-keto esters (e. g. acetyl acetate), organic acids (e. g. acetic acid, propionic acid, acrylic acid, methacrylic acid), a-hydroxy carboxylic acids (e.g. a-hydroxypropionic acid), or else inorganic complex-forming species such as, for example, fluoride, thiocyanate, cyanate and cyanide ions and also ammonia and quaternary ammonium salts such as, for example, tetraalkylammonium salts (chlorides, bromides, hydroxides, etc.), examples being tetramethylammonium and tetrahexylammonium salts.
In addition to the abovementioned central atoms M, which are derived preferably from Si, A1, Ti and Zr, the condensates K may also comprise end groups comprising alkali metal and/or alkaline earth metal atoms.
Various measures, and combinations thereof, may be used to promote the formation of the condensates K, which are used in the composition of the invention, with the desired viscosity behaviour, a relatively low degree of condensation and a relatively low ratio of central atoms to binding sites capable of further condensation. For example, as already mentioned above, it is possible to conduct the polycondensation at relatively low temperatures and/or with high dilution of the (monomeric) hydrolysable starting compounds and/or with sharply curtailed condensation times. In accordance with the invention, however, preference is given to other measures, especially the (concomitant) use of hydrolysable starting compounds whose condensation at room temperature is hindered or prevented by sterically (more) bulky organic groups R
but is able to take place readily at the elevated temperatures required to melt the composition of the invention (and at temperatures above these). A further measure which is preferred in accordance with the invention, and which may be used alternatively or in addition to the measures already mentioned, is the incorporation into the composition of the invention of one or more substances which at the elevated temperatures required to melt the composition (or even at higher temperatures) release a catalyst for the condensation of the remaining condensable binding sites (especially an acid or base).
Finally, a further preferred measure of the invention, which may likewise be used alternatively or in addition to the other measures, comprises using hydrolysable starting compounds with organic groups R
which at the elevated temperatures required to melt the composition (or higher temperatures) are able to enter into a reaction (catalysed or otherwise) with identical or different reactive organic groups R that leads to an organic crosslinking of the existing condensates. In this case it is possible, for example, to incorporate into the composition of the invention a thermal addition-polymerization catalyst and/or condensation-polymerization. catalyst which is activated only at the temperatures required to melt the composition of the invention (or at temperatures above these). In this way, besides the inorganic crosslinking of the condensates K (i.e. further condensation) there may also be an additional organic crosslinking of these condensates. It is of course also possible to carry out such an organic crosslinking photochemically (preferably with added photoinitiator and with UV
irradiation) and in addition to thermal curing (for example, subsequently thereto).
The measures set out above are elucidated in more detail below.
Groups suitable for the steric hindrance or prevention of the condensation of hydrolysed species at room temperature or at a temperature which is necessary for the later required removal of volatile constituents from the reaction mixture, with formation of a solid mass, are bulky organic groups R, such as, for example, unsubstituted or substituted C6-to aryl groups and (cyclo)aliphatic groups which produce a steric hindrance corresponding at least to that of an isopropyl group. Groups R which are preferred for this purpose in accordance with the invention are (unsubstituted or substituted) phenyl groups.
Accordingly, a preferred group of hydrolysable starting compounds for preparing the condensates K is that of the hydrolysable phenylsilanes and diphenylsilanes, examples being phenyltrimethoxysilane and phenyl-_ 7 _ triethoxysilane and the corresponding diphenyl compounds, and also the compounds which have already undergone partial or complete hydrolysis, such as diphenylsilanediol, for example. Additionally or alternatively to the provision of sterically bulky groups R (especially on the silicon atom) it is also possible to provide, in the starting compounds, thermally labile organic groups R, for example ethyl groups and vinyl groups, which decompose at elevated temperatures and so clear the way for a (direct) linking of the central atoms to which they were attached. Accordingly, a further preferred group of starting compounds for the condensates K used in accordance with the invention consists of silanes containing, for example, ethyl groups or vinyl groups, examples being ethyltri(m)ethoxysilane and vinyltri(m)ethoxysilane.
The abovementioned organic crosslinking of the condensates used in accordance with the invention may be brought about, for example, by starting from hydrolysable starting compounds (preferably silicon compounds) which possess organic radicals R which enter into a (chain) reaction at relatively high temperatures, either by themselves or with the aid of a catalyst which is activated at these relatively high temperatures. In this context mention might be made, in particular, of epoxy-containing groups R and of groups R having a reactive carbon-carbon multiple bond (especially double bond). Specific and preferred examples of such radicals R are glycidyloxyalkyl and (meth)acryloyloxyalkyl radicals, which preferably are attached to a silicon atom and preferably have 1 to 6 carbon atoms in the alkyl radical, especially glycidyloxypropyl and methacryloyloxypropyl groups.
Accordingly, a further group of hydrolysable starting compounds used with preference consists of glycidyloxyalkyltri(m)ethoxysilane and methacryl-oyloxyalkyltri(m)ethoxysilane. It is of course also possible to use starting compounds having different groups R which are able to react with one another, such as, for example, groups R with a carbon-carbon multiple bond and groups R with an SH group (which at elevated temperatures arid, if appropriate, with catalysis are able to add onto the carbon-carbon multiple bond) or groups R with an epoxide ring and groups R with an amino group. Very generally, it is possible to use groups R, or combinations of groups R, which at elevated temperatures are able to enter into a catalysed or uncatalysed addition-polymerization reaction or condensation-polymerization reaction.
Addition-polymerization reactions are preferred since unlike condensation reactions they do not lead to any by-products. In such a case it may be advisable to carry out separate preparation of polycondensates containing groups R that are reactive with one another, and to combine the separately prepared polycondensates with one another only as solids.
As already elucidated in more detail above, a further measure for setting the desired viscosity pattern and/or for inhibiting further condensation at room temperature or slightly elevated temperature of the condensates K that are used comprises blocking condensable sites on the central atoms by complex forming species, the corresponding complexes being removed at the temperatures required to melt the composition of the invention (or at temperatures above these) and so clearing the way for further condensation. Complexing agents suitable for this purpose have already been indicated above. Complexing agents of this kind are used preferably in combination with metal compounds which differ (in terms of the central atom) from the hydrolysable silanes, but may also be used in the form of complexed silanes.
One possibility for promoting the further condensation at elevated or high temperatures of the condensates K that are used in accordance with the invention, and by this means setting the desired viscosity behaviour, comprises incorporating into the _ g _ composition of the invention one or more substances which at elevated temperatures release and/or give off species which are catalytically active with respect to the condensation. Examples of such catalytically active species are protons, hydroxide ions, fluoride ions and the like. For example, at temperatures above 160°C, tetraalkylammonium salts release tertiary amines, which are likewise catalytically active. As already mentioned, the same principle may be applied to the organic crosslinking as well, namely by incorporating into the composition of the invention, for example, a thermally activatable free-radical initiator, such as a peroxide or an azo compound, for example, which then initiates the thermal addition polymerization of corresponding organic groups R.
In addition to the above components that are essential and/or preferred for the preparation of the composition of the invention, it is of course also possible to add to the said composition, or to incorporate into it, other components in order, in addition, to achieve other desirable properties. For example, it is possible to use, as some of the starting compounds to be hydrolysed, those containing fully or partly fluorinated radicals R, in order to obtain coatings having hydrophobic and oleophobic properties.
In this case, appropriate starting compounds that might be mentioned include, for example, trialkoxysilanes having a 2- (preferably C2_12) perfluoroalkylethyl radical. Another possibility for introducing fluorine atoms into the composition of the invention is, for example, to use perfluorocarboxylic acids (for example, as complex-forming species) or fluorinated organic copolymers (see below).
If an organic crosslinking of the condensates K
used in the composition of the invention is intended with the aid of groups R capable of an addition polymerization or condensation-polymerization reaction at elevated temperatures (or on irradiation), it may prove to be useful to incorporate into the composition of the invention, as well, corresponding purely organic monomers, which are preferably solid at room temperature and have the capacity to be included in the addition-polymerization and/or condensation-s polymerization reaction of the corresponding organic groups R, examples being caprolactam, malefic acid and pyromellitic dianhydride. The same also relates to the possible incorporation of polymers into the composition of the invention, in which context mention might be made, for example, of silane-functionalized polyesters and other powder coating substances.
The composition of the invention may also comprise customary fillers. Particular preference is given to the incorporation of nanoparticulate oxide powders with or without surface modification (particle size preferably up to 200 nm, in particular up to 100 nm), such as those, for example, of silica, alumina (especially boehmite) and zirconium oxide. These nanoparticulate oxide powders may be incorporated into the composition of the invention either during the preparation of the condensates and/or after their preparation.
Of course, the composition of the invention may also comprise other additives customary for powder coating materials, such as levelling additives, brighteners, dyes, pigments and the like. Preferably, however, at least 50~ by weight and in particular at least 80°s by weight of the composition of the invention comprises the above condensates K. Fillers and/or the abovementioned nanoparticulate oxide powders are used preferably in an amount of up to 25°s by weight, in particular up to 15% by weight.
The composition of the invention may be prepared by techniques familiar to the person skilled in this art, an example being the sol-gel process. This is followed by removal of the volatile auxiliaries (e.g. organic solvents and water) used in the course of the preparation process and of the volatile materials formed during the process (e.g. alcohols in the case of - ~. 1 -the hydrolysis of alkoxides). This removal takes place likewise with the aid of common techniques and equipment, such as rotary evaporators, thin-film evaporators, spray dryers and the like, for example.
Following removal of the volatile constituents to give a solid mass, this mass may be processed further, if desired, to an appropriate particle size or to an appropriate particle size distribution, by grinding, sieving and the like, for example.
The use of the mass obtained in this way (powder coating material) for the coating of substrates, especially those of metals, plastics, glass and ceramic, may likewise take place with the aid of known techniques, but preferably by means of electrostatic powder coating.
The examples which follow serve to illustrate the present invention further. In the context of the invention, the viscosity of the condensates K is measured in accordance with the standards DIN 1342 T1 and T2 and DIN 53018 T1 using a rotational viscometer ("Rheolab MC 20" from Physica Mel~technik GmbH & Co KG, D-70567 Stuttgart) with plate and cone geometry in accordance with DIN 53018 T1 (cone angle 2°). Two measurement systems are employed:
System 1: Cone radius 1.25 cm; can be used for measuring viscosities ranging from 0.5 to 3200 Pa. s;
System 2: Cone radius 3.75 cm; can be used for measuring viscosities ranging from 0.02 to 120 Pa. s.
System 2 allows more precise measurements than system 1 in the viscosity range below 1 Pa.s. In the region of overlap between the two measuring systems, identical condensates at identical temperature give identical viscosity values. The viscosity is measured in all cases at a shear rate of 1.05 rad/s and a heating rate of 2 K/min in the temperature range from 50 to 200°C.
Example 1 48.87 g (0.2 mol) of diphenyldimethoxysilane were added to 14.82 g (0.1 mol) of vinyl-trimethoxysilane. 37.8 g of 0.1 N HC1 were added dropwise to the mixture with vigorous stirring. Gentle heating occurred. Following the addition, stirring was continued at room temperature for 1 h. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about 5 - 6 mbar for 1 h. This gave a free-flowing powder having a viscosity minimum of from 0.02 to 0.03 Pa.s and a melting temperature of 172°C.
After milling (Red Devil, from Erichsen) the powder was applied electrostatically (manual spray gun, from 4Vagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)).
The coated A1 panels were cured in a convection oven at 170°C for 30 minutes. The resultant smooth, transparent coating of 35 ~m in thickness exhibited quasi-thermosetting behaviour, as demonstrated by DSC
analyses (DSC 200, from Netsch).
Example 2 73.3 g (0.3 mol) of diphenyldimethoxysilane were added to 24.8 g (0.1 mol) of methacryl-oyloxypropyltrimethoxysilane (MPTS). A mixture of 1.2 g (0.02 mol) of 'y-A10(OH) and 73 g of O.1 N HC1 was added dropwise to the mixture with vigorous stirring. Marked heating occurred. The dispersal of the y-A10(OH) in the aqueous medium was carried out by first introducing the aqueous HCl solution, then slowly adding the y-A10(OH) (Disperal~ Sol P3, from Condea) with vigorous stirring, and finally treating the suspension with ultrasound at room temperature for about 20 minutes.
Following the addition of the aqueous y-A10(OH) solution, stirring was continued at room temperature for 15 minutes. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about 5 - 6 mbar for 1 hour. This gave a non free-flowing powder having a viscosity minimum of from 0.02 to 0.04 Pa.s and a melting temperature of 147°C.
The powder was applied uniformly to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)) and cured in a convection oven at 170°C for 30 minutes.
The resultant transparent coating exhibited quasi-thermosetting behaviour, as demonstrated by DSC
analyses.
Example 3 61.09 g (0.25 mol) of diphenyldimethoxysilane were added to 14.82 g (0.1 mol) of vinyl trimethoxysilane. A mixture of 1.2 g (0.0047 mol) of N
trimethoxysilylpropyl-N,N,N-trimethylammonium chloride and 45.5 g of 0.1 N HC1 were added dropwise to the mixture with vigorous stirring. Gentle heating occurred. Following the addition, stirring was continued at room temperature for 1 h. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about 5 - 6 mbar for 1 h. This gave a free-flowing powder having a viscosity minimum of from 0 . 3 to 1 . 8 Pa. s and a melting temperature of 90°C.
The powder was applied uniformly to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)) and cured in a convection oven at 170°C for 30 minutes, as demonstrated by DSC analyses.
Example 4 A 50 ml round-bottomed flask was charged with 0.015 mol of a technical-grade solution of zirconium tetra-n-propoxide in n-propanol (amount of Zr[OPr]9, determined by gravimetry: 77.3% by weight). 0.015 mol of methacrylic acid was added slowly dropwise to the zirconium tetra-n-propoxide, with stirring, during which a slightly exothermic reaction occurred. The reaction mixture was stirred in the closed flask for 30 minutes, protected from the light, after which it was processed further directly.
48.87 g (0.2 mol) of diphenyldimethoxysilane were added to 14.82 g (0.1 mol) of vinyl trimethoxysi:Lane. The zirconium tetra-n propoxide/methacrylic acid mixture prepared as described above was added dropwise to this mixture with stirring.
40 g of 0.1 N HC1 were added dropwise with vigorous stirring to the resultant reaction mixture.
Gentle heating occurred. Following the addition, stirring was continued at room temperature for 1 h, with protection from the light. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about 5 -6 mbar for 1 h. This gave a free-flowing powder having a viscosity minimum of from 0.03 to 0.1 Pa.s and a melting temperature of 93°C.
The powder was intimately mixed with 2~ by weight of benzoin (based on the finished powder) and, following a grinding operation, was applied uniformly to aluminium. panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)) and cured in a convection oven at 170°C for 30 minutes, as demonstrated by DSC analyses.
Example 5 39.66 g (0.2 mol) of phenyltrimethoxysilane, 14.82 g (0.1 mol) of vinyltrimethoxysilane and 97.74 g (0.4 mol) of diphenyldimethoxysilane were weighed out in the stated sequence . 91 . 8 g of 0 . 1 N HC1 were added dropwise to the mixture with vigorous stirring. Gentle heating occurred. Following the addition, stirring was continued at room temperature for lh. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of about - 6 mbar for 1 h. This gave a free-flowing powder having a viscosity minimum of from 0.1 to 0.3 Pa.s and a melting temperature of 100°C.
The powder was applied uniformly to aluminium 5 panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)) and cured in a convection oven at 160°C for 30 minutes, as demonstrated by DSC analyses.
Example 6 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [(3-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows:
0.36 g (0.006 mol) of y-A10(OH) was added in portions with vigorous stirring to 18 g of 0.1 N HC1.
Subsequently, 11.61 g (0.1 mol) of malefic acid were added in portions with vigorous stirring to the clear solution formE:d. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of minutes. Following the addition, stirring was 25 continued at room temperature for 4 h. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -20 mbar for 0.5 h, dried under reduced pressure 30 (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of from 4.3 to 8.6 Pa.s and a melting temperature of 90°C, an average density of 1.29 g/cm3 and a particle size distribution of 20 - 100 N,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSC analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 7 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [(3-(3,4-epoxy-cyclohexyl)ethyl]trimethoxysilane (ETMS). To this solution were added in portions 26.88 g (0.025 mol) of finely mortared glycidyl-endcapped poly(bisphenol A-co-epichlorohydrin) (Mn approximately 1075). After about 15 minutes, a clear solution had formed (mixture A). A
mixture B was prepared in parallel as follows : 11. 61 g (0.1 mol) of malefic acid were added in portions with vigorous stirring to 18 g of 0.1 N HCl. Following the addition, stirring was continued at room temperature for 10 minutes so that a transparent mixture formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of minutes. Following the addition, stirring was continued at room temperature for 4 h. As the reaction 25 time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and 30 subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of 10 Pa.s and a melting temperature of 93°C, an average density of 1.29 g/cm3 and a particle size distribution of 20 - 100 Vim. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSC analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 8 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24. 63 g (0.1 mol) of [(3- (3, 4-epoXy-cyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A
mixture B was prepared in parallel as follows: 11.61 g (0.1 mol) of malefic acid were added in portions to 18 g of 0.1 N HC1. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. As the reaction time increased, the suspension initially present became a white, solid mass. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-f:Lowing powder having a viscosity minimum of 13.3 Pa.s and a melting temperature of 102°C, an average density of 1.29 g/cm3 and a particle size distribution of 20 - 100 Vim. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSC analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 9 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS), 5.44 g (0.015 mol) of bis(3-glycidyloxy-propyl)tetramethyldisiloxane (BGTS), 6.54 g (0.03 mol) of pyromellitic dianhydride and up to 3.00 g (0.05 mol) of Si02 (10.00 g of Organosol~ (silica sol in 2-propanol, Si02 content in the sol - 29. 9%, from Bayer) ) were added at room temperature with vigorous stirring to 24.63 q (0.01 mol) of [(3-(3,4-epoxycyclohexyl)ethyl] trimethoxy-silane (ETMS).
With vigorous stirring and ice cooling, 18 g of 0.1 N HC1 was added dropwise to the white suspension formed over the course of 5 minutes. Following the addition, stirring was continued at room temperature for 14 h. With increasing reaction time, the suspension initially present turned into a transparent sol. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 - 20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of from 80 to 95 Pa.s and a melting temperature in the range from 95 to 105°C, an average density of 1.26 g/cm3 and a particle size distribution of 10 - 100 ~,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco0, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at from 120 to 150°C for 20 to 120 minutes. The resultant - 18a -coherent, transparent coating of 10 - 20 ~m in thickness possesses good adhesion (Gt 0/l, TT 0/1).
Example 10 24.44 g (0.1 mol) of diphenyldimethoxysilane 5 (DPDMS), 2.3 g (0.01 mol) of dodecanedicarboxylic acid (DD) and 'up to 6 g (0.1 mol) of Si02 (20.00 g of Organosol~ (silica sol in 2-propanol, Si02 content in the sol - 29.9%, from Bayer)) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [(3-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows: 11.61 g (0.1 mol) of malefic acid were added in portions with vigorous stirring to the clear solution formed. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. With increasing reaction time, the suspension initially present turned into a clear sol. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 - 20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of from 6.5 to 10 Pa.s and a melting temperature in the range from 90 to 100°C, an average density of 1.29 g/cm3 and a particle size distribution of 10 - 100 ~,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at from 120 to 150°C for from 20 to 120 minutes. The resultant coherent, transparent coating of 10 - 25 ~m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 11 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) and up to 3.00 g (0.05 mol) of Si02 (10.00 g of Organosol~ (silica sol in 2-propanol, Si02 content in the sol - 29.9%, from Bayer)) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [~3-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows: 11.61 g (0.1 mol) of malefic acid were added in portions with vigorous stirring to the clear solution formed. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. With increasing reaction time, the suspension initially present turned into a clear sol. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 - 20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having a viscosity minimum of 8.4 Pa.s and a melting temperature in the range from 85 to 95°C, an average density of 1.29 g/cm3 and a particle size distribution of 10 - 100 ~,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at from 120 to 150°C for from 20 to 120 minutes. The resultant coherent, transparent coating were 10 - 25 ~m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 12 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [(3-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows:
0.36 g (0.006 mol) of y-A10(OH) was added in portions with vigorous stirring to 18 g of 0.1 N HC1.
Subsequently, 11.61 g (0.1 mol) of malefic acid were v added in portions with vigorous stirring to the clear solution formed. Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. With increasing reaction time, the suspension initially present turned into a white, solid mass . The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This 15 gave a free-flowing powder having a viscosity minimum of from 4.3 to 8.6 Pa.s and a melting temperature of 90°C, an average density of 1.29 g/cm3 and a particle size distribution of 20 - 100 ~tm. Following the melting operation, the powder has thermosetting properties, as 20 demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)).
The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion to the substrate (Gt 0/1, TT 0/1) .
Example 13 24.44 g (0.1 mol) of diphenyldimethoxysilane (DPDMS) and 6.54 g (0.03 mol) of pyromellitic - 21a -dianhydride were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [~3-(3,4-epoxycyclo-hexyl)ethyl]trimethoxysilane (ETMS).
With vigorous stirring and ice cooling, 18 g of 0.1 5 N HCl was added dropwise to the white suspension formed over the course of 5 minutes. Following the addition, stirring was continued at room temperature for 14 h. With increasing reaction time, the suspension initially present turned into a transparent sol. The product was treated on a rotary evaporator at 40°C and a final pressure of 10 - 20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having an average density of 1.26 g/cm3 and a particle size distribution of 10 - 100 Nxn. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (A1 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)). The coated aluminium panels were heat-treated in a convection oven at from 120 to 150°C for 20 to 120 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 14 12.22 g (0.05 mol) of diphenyldimethoxysilane (DPDMS) were added at room temperature with vigorous stirring to 24.63 g (0.1 mol) of [~i-(3,4 epoxycyclohexyl)ethyl]trimethoxysilane (ETMS) (mixture A). A mixture B was prepared in parallel as follows:
5.8 g (0.05 mol) of malefic acid were added in portions with vigorous stirring to the clear solution formed.
Following the addition, stirring was continued at room temperature for 10 minutes until a transparent mixture had been formed.
With vigorous stirring and ice cooling, mixture B was added dropwise to mixture A over the course of 30 minutes. Following the addition, stirring was continued at room temperature for 4 h. With increasing reaction time, the suspension initially present turned into a white, solid mass . The product was treated on a rotary evaporator at 40°C and a final pressure of 10 -20 mbar for 0.5 h, dried under reduced pressure (7 mbar, 45°C) in a convection oven for 5 h, and subjected to grinding (Red Devil, from Erichsen). This gave a free-flowing powder having an average density of 1.29 g/cm3 and a particle size distribution of 20 -100 ~,m. Following the melting operation, the powder has thermosetting properties, as demonstrated by DSM
analyses. The coating powder is applicable electrostatically using a conventional manual spray gun (from Wagner-ESB) to aluminium panels (Al 99.5 mill finish, pretreated with alkaline surfactant (Almeco~, from Henkel)).
The coated aluminium panels were heat-treated in a convection oven at 130°C for 20 minutes. The resultant coherent, transparent coating of 10 - 20 ~,m in thickness possesses good adhesion (Gt 0/1, TT 0/1).
Example 15 A mixture of 25.3 ml of glycidyloxypropyltrimethoxysilane, 80.3 ml of phenyltrimethoxysilane, 16.8 ml of silica sol 300-30 (300, from Bayer), 10 ml of water and 0.52 ml of hydrochloric acid was stirred intensively until the temperature of the mixture had risen, owing to the heat of reaction, to about 45 to 50°C. Immediately thereafter, the mixture was concentrated on a rotary evaporator at a bath temperature of approximately 50°C.
When solvent no longer went over, a viscous material had formed which on cooling could be pulverized. When the powder was heated on a hotplate at 200°C, the powder changed to a low-viscosity melt, with foaming, and slowly solidified over the course of from 10 to 15 minutes. A transparent, highly glossy coat was formed.
Example 16 27.6 ml of phenyltrimethoxysilane, 17 g of diphenylsilanediol, 14 g of tetramethylammonium hydroxide x 5 H20 and 10 g of H20 was stirred intensively until the mixture had warmed, owing to the heat of reaction, to about 45 to 50°C. Drying on a rotary evaporator gave a powder which formed a very low-viscosity melt and hardened within 1 to 2 hours at 200°C (decomposition of the tetramethylammonium hydroxide).
Claims (25)
1. Solid, meltable and heat-curable composition which comprises condensates K derived from at least one hydrolysable silane and, if desired, from one or more hydrolysable metal compounds, central atoms M of the condensates K bearing groups A which permit further condensation of the condensates, at least 70% of the central atoms M having one or more nonhydrolysable organic groups R attached thereto, some of which may be replaced by complex-forming species coordinated with the central atoms M, and the condensates K passing through a viscosity minimum in the range from 10 mPa.s to 150 Pa.s within the temperature range from 50 to 200°C.
2. Composition according to Claim 1, characterized in that at least 75 and preferably at least 85% of the central atoms M are silicon atoms.
3. Composition according to either of Claims 1 and 2, characterized in that the condensates K have at least 5 and up to 300, preferably at least 10 and up to 200 central atoms M.
4. Composition according to any one of Claims 1 to 3, characterized in that the central atoms M other than silicon are selected from the group Al, Ti and Zr.
5. Composition according to any one of Claims 1 to 4, characterized in that at least 80 and preferably at least 90% of the central atoms M have at least one organic group R.
6. Composition according to any one of Claims 1 to 5, characterized in that the numerical ratio x of the total number of central atoms M present in the condensates to the sum of the groups A which these central atoms bear and which permit further condensation is from 1:2 to 20:1, preferably from 1:1 to 10:1.
7. Composition according to any one of Claims 1 to 6; characterized in that the groups A which permit further condensation of the condensates K are selected from hydroxyl, alkoxy, aryloxy, acyloxy, enoxy and oxime groups.
8. Composition according to any one of Claims 1 to 7, characterized in that the organic groups R are selected at least in part from sterically hindered groups, especially unsubstituted or substituted C6-10 aryl groups and (cyclo)aliphatic groups having a steric hindrance which is at least equal to that of an isopropyl group.
9. Composition according to any one of Claims 1 to 8, characterized in that the organic groups R are selected at least in part from groups which are able to enter into a catalyzed or uncatalyzed thermal and/or photochemical addition-polymerization or condensation-polymerization reaction.
10. Composition according to Claim 9, characterized in that the organic radicals R include polymerizable carbon-carbon multiple bonds and/or epoxide rings.
11. Composition according to either of Claims 9 and 10, characterized in that one portion of the groups R
contain epoxide rings and another portion of the groups R contain amino groups and/or in that one portion of the groups R contain carbon-carbon multiple bonds and another portion of the groups R contain thiol groups.
contain epoxide rings and another portion of the groups R contain amino groups and/or in that one portion of the groups R contain carbon-carbon multiple bonds and another portion of the groups R contain thiol groups.
12. Composition according to any one of Claims 1 to 11, characterized in that some of the groups R contain fluorine atoms.
13. Composition according to any one of Claims 1 to 12, characterized in that it further comprises a thermally activatable or releasable addition-polymerization catalyst for the organic crosslinking and/or one or more substances which at elevated temperatures release a catalyst for the further condensation of the condensates that are present.
14. Composition according to any one of Claims 1 to 13, characterized in that the condensates K make up at least 50% by weight, preferably at least 80% by weight, of the composition.
15. Composition according to any one of Claims 1 to 14, characterized in that it further comprises fillers and/or nanoparticulate oxide powders in an amount of up to 25% by volume.
16. Process for coating substrates with a powder coating material, characterized in that the powder coating material comprises the composition according to any one of Claims 1 to 15.
17. Process according to Claim 16, characterized in that the powder coating material is applied by electrostatic powder coating.
18. Process according to either of Claims 16 and 17, characterized in that the substrates comprise those of metals, plastics, glass or ceramic.
19. Use of the composition according to any one of Claims 1 to 15 in a powder coating material for producing abrasion-resistant and anticorrosive coatings on metals.
20. Process for preparing a solid, meltable, heat-curable composition, comprising the controlled hydrolytic polycondensation of one or more hydrolysable compounds of silicon and/or corresponding silanols, alone or in combination with one or more hydrolysable metal compounds, at least some of the compounds used having non-hydrolysable organic groups R, and/or of corresponding precondensates, in order to obtain condensates which within the temperature range from 50 to 200°C pass through a viscosity minimum in the range from 10 mPa.s to 150 Pa.s, and the subsequent removal of volatile compounds used in the polycondensation or formed during it.
21. Process according to Claim 20, characterized in that at least one of the hydrolysable compounds used is a silane having one or two phenyl groups as groups R.
22. Process according to either of Claims 20 and 21, characterized in that at least one of the hydrolysable compounds used is a silane having a radical R containing epoxy groups and/or methacrylic groups and/or vinyl groups.
23. Process according to any one of Claims 20 to 22, characterized in that the hydrolysable metal compounds are present, at least in part, in complexed form.
24. Process according to any one of Claims 20 to 23, characterized in that the metal compounds are selected from compounds of Al, Ti and Zr.
25. Process according to any one of Claims 20 to 24, characterized in that incorporated into the composition is a thermally activatable and/or releasable catalyst for the further condensation of the condensates K and/or the addition polymerization or condensation polymerization of corresponding organic groups R and also, if desired, a photochemically activatable catalyst for the addition/condensation polymerization of corresponding organic groups R.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19817785.2 | 1998-04-21 | ||
| DE19817785A DE19817785A1 (en) | 1998-04-21 | 1998-04-21 | Fusible and heat-curable solid materials, useful as the basis of coating powders for plastics, glass, ceramics and especially metals |
| PCT/EP1999/002666 WO1999054412A1 (en) | 1998-04-21 | 1999-04-20 | Solid, meltable, thermohardeninig mass, its production and its use |
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| CA2329731A1 true CA2329731A1 (en) | 1999-10-28 |
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| EP (1) | EP1088036B1 (en) |
| JP (1) | JP2002512293A (en) |
| CN (1) | CN1301283A (en) |
| AT (1) | ATE229999T1 (en) |
| AU (1) | AU3928199A (en) |
| CA (1) | CA2329731A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8114513B2 (en) | 2006-04-27 | 2012-02-14 | Sachtleben Chemie Gmbh | UV-curable undercoat |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100795714B1 (en) * | 2000-08-21 | 2008-01-21 | 다우 글로벌 테크놀로지스 인크. | Organosilicate resins as hardmasks for organic polymer dielectrics in fabrication of microelectronic devices |
| GB0212324D0 (en) * | 2002-05-29 | 2002-07-10 | Dow Corning | Silicon composition |
| US7802450B2 (en) | 2003-03-14 | 2010-09-28 | Central Glass Company, Limited | Organic-inorganic hybrid glassy materials and their production processes |
| WO2004081086A1 (en) * | 2003-03-14 | 2004-09-23 | Central Glass Company, Limited | Organic-inorganic hybrid vitreous material and method for producing same |
| US7451619B2 (en) | 2003-06-26 | 2008-11-18 | Central Glass Company, Limited | Organic-inorganic hybrid glassy materials and their production processes |
| DE10353507A1 (en) | 2003-11-17 | 2005-06-30 | Basf Coatings Ag | Hydrolysates and / or condensates of oligomers and polymers containing epoxide and silane groups, process for their preparation and their use |
| DE10357116A1 (en) | 2003-12-06 | 2005-07-07 | Solvay Barium Strontium Gmbh | Deagglomerated barium sulfate |
| JP2005239498A (en) * | 2004-02-27 | 2005-09-08 | Central Glass Co Ltd | Organic-inorganic hybrid glassy material and its production method |
| KR100935157B1 (en) | 2006-04-19 | 2010-01-06 | 연세대학교 산학협력단 | Surface modified organic·inorganic hybrid glass and producing method thereof |
| WO2007120014A1 (en) * | 2006-04-19 | 2007-10-25 | Industry-Academic Cooperation Foundation, Yonsei University | Surface modified organic·inorganic hybrid glass, protecting group induced alcohol or its derivative and producing method thereof |
| DE102008031360A1 (en) | 2008-07-04 | 2010-01-14 | K+S Ag | A method for producing curable compositions comprising coarse and / or nanoscale, coated, deagglomerated and preferably functionalized magnesium hydroxide particles, and of cured thermoplastic or thermosetting polymers or composites comprising deagglomerated and homogeneously distributed Magnesiumhydroxidfüllstoffpartikel |
| US20140323677A1 (en) * | 2011-09-01 | 2014-10-30 | Toagosei Co., Ltd. | Thermal-shock-resistant cured product and method for producing same |
| WO2014091811A1 (en) * | 2012-12-11 | 2014-06-19 | 東レ株式会社 | Heat-curable coloring composition, cured film, touch panel provided with said cured film, and method for producing touch panel using said heat-curable coloring composition |
| CN113278315A (en) * | 2021-05-27 | 2021-08-20 | 广州大学 | Protective coating and preparation method and application thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL84025A0 (en) * | 1986-10-03 | 1988-02-29 | Ppg Industries Inc | Organosiloxane/metal oxide coating compositions and their production |
| DE3917535A1 (en) * | 1989-05-30 | 1990-12-06 | Fraunhofer Ges Forschung | Scratch-resistant materials - prepd. by hydrolysis of silane-based mixt. with removal of volatile hydrolysis prods. before applying coating or moulding |
| DE4011045A1 (en) * | 1990-04-05 | 1991-10-10 | Fraunhofer Ges Forschung | METHOD FOR COATING PLASTIC SUBSTRATES AND VARNISH FOR USE IN THIS METHOD |
| US5280098A (en) * | 1992-09-30 | 1994-01-18 | Dow Corning Corporation | Epoxy-functional silicone resin |
-
1998
- 1998-04-21 DE DE19817785A patent/DE19817785A1/en not_active Withdrawn
-
1999
- 1999-04-20 AT AT99922116T patent/ATE229999T1/en not_active IP Right Cessation
- 1999-04-20 CA CA002329731A patent/CA2329731A1/en not_active Abandoned
- 1999-04-20 AU AU39281/99A patent/AU3928199A/en not_active Abandoned
- 1999-04-20 WO PCT/EP1999/002666 patent/WO1999054412A1/en active IP Right Grant
- 1999-04-20 JP JP2000544748A patent/JP2002512293A/en active Pending
- 1999-04-20 CN CN99806343A patent/CN1301283A/en active Pending
- 1999-04-20 DE DE59903843T patent/DE59903843D1/en not_active Expired - Lifetime
- 1999-04-20 EP EP99922116A patent/EP1088036B1/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8114513B2 (en) | 2006-04-27 | 2012-02-14 | Sachtleben Chemie Gmbh | UV-curable undercoat |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002512293A (en) | 2002-04-23 |
| EP1088036B1 (en) | 2002-12-18 |
| WO1999054412A1 (en) | 1999-10-28 |
| DE59903843D1 (en) | 2003-01-30 |
| EP1088036A1 (en) | 2001-04-04 |
| DE19817785A1 (en) | 1999-10-28 |
| CN1301283A (en) | 2001-06-27 |
| ATE229999T1 (en) | 2003-01-15 |
| AU3928199A (en) | 1999-11-08 |
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