This invention provides a water based paint composition containing polyurethane resin which is formed by urethanation reaction of polyisocyanate compound with polyalkylene glycol and a further reaction of so formed isocyanate-containing prepolymer with a monohydric alcohol having at least 5 carbons, and water-soluble organic solvent having boiling point not higher than 150xc2x0 C.; and provides also a process for forming multi-layered coating, which comprises applying onto a metallic object cationic electropaint, above-described water based paint composition, water based intermediate coating and top coating, by the order stated.

This invention relates to water based paint compositions which are useful for improving chipping resistance and corrosion resistance, etc, of multi-layered coating formed of layers of cationic electropaint, intermediate coating and top coating, which are formed on metallic objects, in particular, car bodies and the like; and also to a process for forming multi-layered coating using such a water based paint composition.
Improvement in resistance properties of multi-layered coating composed of cationic electropaint, intermediate coating and top coating, which is applied onto outer shell portions of metallic car bodies, in particular, prevention of peeling or chipping due to impact exerted by collision with pebbles or gravel upflung by wheels of running cars, and prevention of thereby caused deterioration in corrosion resistance of the coating and progress in corrosion of the metal (coated object or substrate), is being attached increasing importance. For example, in cold districts of Europe and the United States, gravel mixed with a large amount of rock salt is often spread on road to prevent surface freezing, and cars running on such road frequently are hit with rock salt grains or small pebbles upflung by their wheels. Impacts so exerted on coated surfaces of car bodies frequently induce a phenomenon of local peeling of the coating, which is called xe2x80x9cchippingxe2x80x9d. When the metallic substrate surfaces at the hit spots are exposed as the coating thereon is peeled off, rusting starts from those spots and corrosion progresses easily. Other problems also occur such that chipping of top coating markedly impairs aesthetic appearance of cars. Stripping of coated films by chipping usually takes place more frequently at cars"" base or bottom portions and lower part of shell bodies around wheels, but it can occur also at hood and roof portions and local corrosion appreciably progresses within about a half to one year.
For the purpose of preventing such progress in corrosion of metal substrate caused by chipping, for example, U.S. Pat. No. 4,755,435 proposed to apply a barrier coating composed chiefly of modified polyolefin resin between an electrodeposited coating and intermediate coating. The modified polyolefin resin, however, is given a relatively high molecular weight and a large amount of organic solvent is required to dilute it to a viscosity suitable for application. This leads to such defects as adverse effects on safety and health of operators at the application time, environmental pollution after the application and danger of fire, explosion and the like during the application and baking. Moreover, when this barrier coating is left uncured before application of intermediate coating and top coating thereon, finished appearance factors of the multi-layered coating such as flowxe2x80x94andxe2x80x94leveling property are liable to be impaired and, therefore, it is the current practice to heat and dry the barrier coating before applying an intermediate coating thereon.
We have engaged in concentrative studies with the view to solve those problems as described above, and now discovered: a water based paint composition containing a polyurethane resin obtained by reaction of an isoiyanate-containing prepolymer with monohydric alcohol having at least 5 carbons, said prepolymer having been formed by urethanation reaction of polyisocyanate compound with polyalkylene glycol; and a water-soluble organic solvent having boiling point not higher than 150xc2x0 C., excels in chipping resistance; and furthermore, application of this water based paint composition between a cationic electropaint coating and an intermediate coating enables to form multi-layered coating exhibiting excellent chipping resistance. The present invention is whereupon completed.
Thus, according to the present invention, water based paint compositions (xe2x80x9cpresent paint compositionsxe2x80x9d) are provided, which are characterized by containing
(a) polyurethane resin obtained by reacting isocyanate-containing prepolymer with monohydric alcohol having at least 5 carbon atoms, said isocyanate-containing prepolymer having been obtained by urethanation reaction of polyisocyanate compound with polyalkylene-glycol, and
(b) water-soluble organic solvent having boiling point not higher than 150xc2x0 C.
Hereinafter the present paint composition is explained in further details.
The present paint composition can be formulated by, for example, causing conventional water based paint to contain: (a) polyurethane resin which is obtained by reacting isocyanate-containing prepolymer with monohydric alcohol having at least 5 carbon atoms, said prepolymer having been formed by urethanation reaction of polyisocyanate compound with polyalkylene glycol; and (b) a water-soluble organic solvent boiling at no higher than 150xc2x0 C.
As such water based paints in which the polyurethane resin (a) and the water-soluble organic solvent (b) are incorporated following the present invention, those paints known per se can be used. For example, water based paints which contain, as vehicle component, base resin such as water-dispersible or water-soluble acrylic resin, polyester resin, alkyd resin, urethane resin and the like which have crosslinkable functional groups, e.g., hydroxyl groups, and crosslinking agent such as hydrophilic or hydrophobic melamine resin; and as individual occasions demand, further contain such paint additives as coloring pigment, extender, antisettle agent, organic solvent and the like, can be used, which are formed by mixing and dispersing those components with, and in, water.
Polyurethane resin (a) is obtained by forming an isocyanate-containing prepolymer by urethanation reaction of polyisocyanate compound with polyalkylene glycol, and further reacting the prepolymer with monohydric alcohol having at least 5 carbons.
Polyisocyanate compounds are those containing at least two, preferably two, isocyanate groups per molecule. As such, aliphatic, alicyclic and aromatic diisocyanate compounds are conveniently used, in particular, aliphatic and alicyclic diisocyanates are preferred. Examples of aliphatic and alicyclic diisocyanates include C2-C12 aliphatic diisocyanates such as hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate and lysine diisocyanate; C4-C18 alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (isophorone diisocyanate), 4,4xe2x80x2-dicyclohexylmethane diisocyanate, methylcyclohexylene diisocyanate and isopropylidenedicyclohexyl-4,4xe2x80x2-diisocyanate; and modifications of those diisocyanates (e.g., carbodiimide-, urethodione- or urethoimine-containing modified products). They may be used either singly or as combination of more than one.
Polyalkylene glycols to be reacted with these polyisocyanate compounds include polyether glycols which are obtained by (block or random) polymerization or copolymerization of at least one compound selected from alkylene oxides (for example, C2-C7 alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide and the like) and cyclic ethers (for example, tetrahydrofuran and the like). Specific examples include polyethylene glycol, polypropylene glycol, polyethylene-propylene (block or random) glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol and polyoctamethylene ether glycol. It is generally preferred for these polyalkylene glycols to have number-average molecular weight ranging 500-5,000, in particular, 1,000-3,000.
In the occasion of preparing such polyurethane resin (a), it is permissible to use, concurrently with those polyisocyanate compound and polyalkylene glycol, low molecular weight glycol(s) having number-average molecular weight less than 500, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol and bishydroxymethylcyclohexane. Use rate of such low molecular weight glycol is usually not more than 20% by weight, preferably 0.1-20% by weight, inter alia 0.5-10% by weight, based on the weight of the polyalkylene glycol used.
Urethanation reaction of polyisocyanate compound with polykylene glycol (and if necessary low molecular weight glycol) may be performed under conditions known per se. These components are preferably reacted at such ratios that the formed isocyanate-containing prepolymer will contain at least two, preferably two, isocyanate groups per molecule.
Examples of monohydric alcohols having at least 5, preferably 6-10, carbon atoms, to be reacted with so obtained isocyanate-containing prepolymer include aliphatic alcohols such as amyl alcohol, hexyl alcohol, ethylbutyl alcohol, heptanol, octyl alcohol, 2-ethylhexyl alcohol, nonyl alcohol, decanol and the like. By effecting urethanation reaction of such monohydric alcohol with substantially all of the isocyanate groups contained in the above isocyanate-containing prepolymer, intended polyurethane resin (a) is obtained.
Said polyurethane resin (a) has in its molecule hydrophilic segments derived from polyalkylene glycol and hydrophobic segments derived from monohydric alcohol having at least 5 carbons, and may have number-average molecular weight usually within a range of 700-10,000, in particular, 1,300-5,000. It is desirable that said polyurethane resin (a) does not substantially have functional groups such as hydroxyl, isocyanate and the like in its molecule. Such polyurethane resin (a) includes those known per se, for example, commercially available TAFIGEL(trademark) PUR-60xe2x80x9d (Munzing Chemie GmbH).
Said water-soluble organic solvent (b) is one which has such solubility that at least 50 parts by weight, preferably at least 70 parts by weight, thereof is soluble in 100 parts by weight of water at 20xc2x0 C. Said water-soluble organic solvent (b) preferably has boiling point not higher than 150xc2x0 C., in particular, within a range of 80-130xc2x0 C. Specific examples of such water-soluble organic solvent (b) include: methyl lactate, dioxolan, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, monopropylene glycol methyl ether, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol and tert-butyl alcohol. In particular, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and monopropylene glycol methyl ether are preferred.
In the present paint compositions, blend ratios of polyurethane resin (a) and water-soluble organic solvent (b) can be selected over a wide range depending on, for example, kinds of those components used. Usually suitable range for polyurethane resin (a) is 0.01-10 parts by weight, in particular, 1-5 parts by weight (as solid) and that for water-soluble organic solvent (b) is 3-40 parts by weight, in particular, 5-20 parts by weight, both per 100 parts by weight of total resin component excepting that of polyurethane resin (a), in each paint composition according to the present invention.
While present paint compositions are useful as any of under coating, intermediate coating and top coating, because coating films thereof excel in chipping resistance, they can improve chipping resistance of multi-layered coating. For example, in an occasion of forming multi-layered coating on a metal substrate by successively applying a cationic electropaint (A), intermediate coating (C) and top coating (D), a present paint composition is applied onto the cationic electropaint-coated surface prior to application of an intermediate coating (C) thereon, to cause the coating film of the present paint composition to be present between the cationic electropaint coating and the intermediate coating, whereby to improve chipping resistance of resulting multi-layered coating.
Thus, according to the present invention, also a process (xe2x80x9cthe present processxe2x80x9d) for forming multi-layered coating is provided, which process comprising applying onto a metallic object or substrate a cationic electropaint (A), a present paint composition (B), a water based intermediate coating (C) and top coating (D), by the order stated.
Said metallic object is a substrate on which a multi-layered coating is to be formed according to the present process, which is subject to no particular limitation so long as the material has an electroconductive metallic surface compatible with cationic electropaint coating. More specifically, for example, materials made of iron, copper, aluminum, alloys containing these metals; and articles on which these metals are plated or vacuum deposited may be used. Shell bodies of automobiles, trucks, bases, motorcycles for which plates of those metals or alloys are used are suitable. Surfaces of such metallic objects are preferably chemically pretreated with phosphate, chromate or the like, prior to the cationic electropaint application.
As cationic electropaint (A), those known per se can be used. More specifically, water based paints in which basic resins which can be rendered water-soluble or water-dispersible when neutralized with organic or inorganic acid, such as epoxy, acrylic or polybutadiene-type resins having many amino groups in their skeletal structure are used as the base resin are useful. Such base resin(s) are blended with neutralizers, pigments (e.g., coloring pigments, extenders, rust protective pigments and the like), hydrophilic solvent, water, and if necessary curing agents, crosslinking agents and other additives and formed into paint compositions by a method known per se. As neutralizers to render such basic resins (which are usually used as dissolved in hydrophilic solvent) water-soluble or water-dispersible, organic acids such as acetic acid, hydroxyacetic acid, propionic acid, butyric acid, lactic acid and glycine; and inorganic acids such as sulfuric acid, hydrochloric acid and phosphoric acid can be used. Suitable blend ratio of the neutralizer is within a range of from about 0.1 to about 0.4 in terms of the neutralization equivalent, to base value (about 30-about 200 mgKOH/g) of said resin.
Such a cationic electropaint (A) is diluted with, for example, deionizing water to a solid content of about 5-40% by weight, and applied onto earlier described metallic object to effect cationic electrodeposition by a process known per se, while being maintained at a pH within a range of 5.5-8.0. The thickness of the electropaint coating usually is within a range of 10-40 xcexcm, preferably 15-30 xcexcm, as cured coating film. Such electropaint coating can be cured by heating at temperatures of about 140-about 210xc2x0 C. for around 10-40 minutes. According to the present process, above-described present paint composition (B) is applied either onto the electropaint-coated surface after said heating for curing or onto the unheated, uncured electropaint-coated surface.
The paint composition (B) is adjusted to have, for example, a viscosity of 10-40 seconds/ Ford Cup #4/20xc2x0 C. and a solid content of 30-60% by weight, and thereafter applied onto cured or uncured cationic electropaint-coated surface by means known per se, e.g., spray coating, brush coating, dip coating and the like. The applied coating film thickness suitably ranges, as dry film thickness, 1-20 xcexcm, in particular, 5-15 xcexcm.
Said polyurethane resin (a) in the present paint compositions has a function to raise viscosity of the compositions, but because the compositions also contain water-soluble organic solvent (b), they scarcely show viscosity rise and hence excel in coating operability. On the other hand, said water-soluble organic solvent (b) has relatively low boiling point and volatilizes during coating operations and does not substantially remain in the coating film after the application. Hence viscosity of the coating rapidly rises after the application and the resulting film is free from sagging or sliding down.
According to the present process, after applying a present paint composition (B) onto the electropaint (A)-coated surface, a water based intermediate coating (C) is applied onto the surface of the applied paint composition (B), preferably without intervening heating for curing.
As such water based intermediate coating (C), those known per se and excel in adhesive property, leveling property, distinctness-of-image gloss, overbake resistance and weatherability can be used. More specifically, water based intermediate paints containing, as vehicle component, base resin such as short oil or ultrashort oil alkyd resin not more than 30% in oil length, or oil-free polyester resin; and crosslinking agent such as amino resin: said vehicle component being suitably blended with extender, coloring pigment and other paint additives, can be conveniently used. As said alkyd resin and polyester resin, those preferred have hydroxyl values within a range of 60-140 mgKOH/g and acid values within a range of 10-50 mgKOH/g, and wherein unsaturated oil (or unsaturated fatty acid) is used as modifying oil. As amino resin serving as a crosslinking agent, for example, C1-C5 alkyletherified melamine resin, urea resin or benzoguanamine resin are suitable. Generally preferred blend ratios of those components are, based on the solid weight, 65-85% of such alkyd resin and oil-free polyester resin, in particular, 70-80%; 35-15% of the amino resin, in particular, 30-20%. It is also permissible to replace a part or whole of the amino resin with polyisocyanate compound or blocked polyisocyanate compound. It is generally preferred for coating film formed of such an intermediate paint to have a hardness (pencil hardness) within a range of 3B-2H.
Application of the water based intermediate paint (C) onto the surface which is coated with a present composition (B) can be performed in the manner similar to earlier described method. Usually preferred thickness for the coated film ranges 20-50 xcexcm, in particular, 25-40 xcexcm, as cured film thickness. After the application, the applied film of (C) or the two films of (B) and (C) can be cured by, for example, heating at temperatures of about 120-about 170xc2x0 C., in particular, at about 120-150xc2x0 C., for around 10-40 minutes. After curing these films or not curing the films but leaving (them uncured, top coating (D) is applied onto the surface coated with the water based intermediate coating (C).
As the top coating (D), paints known per se and are capable of forming coating films excelling in distinctness-of-image-gloss, leveling property, gloss, weatherability and chemical resistance can be used. More specifically, for example, liquid paints derived from acrylic resin/amino resin system, alkyd resin/amino resin system and polyester resin/amino resin system can be used, which may be in the form of organic solution, non-aqueous dispersion, aqueous solution or aqueous dispersion.
Top coating paints (D) can be classified into solid color paints formed by blending these liquid paints with solid color pigments; metallic paints formed by blending them with metallic pigments; and clear paints which contain little or no solid color or metallic pigment. According to the present process, one or more of these paints are used to form the top coating by 1-coat system, 2-coat system and the like. More specifically, there is solid color finish by 1-coat system in which a solid color paint is applied onto the intermediate coating surface to a cured film thickness of 10-40 xcexcm, in particular, 15-30 xcexcm, and heated at temperatures of about 100-about 160xc2x0 C. for around 10-40 minutes; or solid color or metallic finish method conducted by 2-coat-1-bake system or 2-coat-2-bake system, in which a solid color paint or metallic paint is applied onto the intermediate coating-applied surface to a cured film thickness of 10-30 xcexcm, in particular, 15-25 xcexcm, and either cured by heating or left uncured; onto which further a clear paint is applied to a cured film thickness of 20-60 xcexcm, in particular 30-50 xcexcm, and heated at temperatures from about 100 to about 160xc2x0 C. for around 10-40 minutes.
According to the present process, a coating film of the present paint composition (B) is formed between a cationic electropaint coating and an intermediate coating, whereby chipping resistance of ultimately formed multi-layered coating can be drastically improved. The present paint compositions, furthermore, have such advantages as (1) being free of environmental pollution problem or safety problem, because they are water based paints, (2) being capable of forming coatings of high decorative effect, as they are concurrently baked with intermediate coating, (3) good adhesive property to cationic electropaint coating, and (4) good adhesive property to intermediate coating.
Hereinafter the invention is more specifically explained, referring to Examples and Comparative Examples in which parts and percentages are by weight and thickness values of coating films are those of cured films.


A method for making a black matrix type shadow mask color television tube. A shadow mask with standard size apertures is sprayed with a black brushing cellulose lacquer while at the same time drawing air, at high velocities, through the apertures to reduce the size of said apertures. A sufficient quantity of sprayed lacquer is utilized to obtain a 10% reduction in aperture size. The mask is then utilized to coat the tube's screen, i.e. its inside face, with a colloidal graphite paint to form the required adherent black matrix surface on said screen having a plurality of holes therein. The apertures of the shadow mask are then restored to their original size by rinsing the mask in acetone to remove the lacquer coating. The resultant original size apertures of the shadow mask are utilized to form the pattern of phosphor dots on the screen overlapping the holes in the black matrix.

This invention relates to the manufacture of color television picture tubes incorporating shadow masks, and more particularly to such tubes utilizing the so-called "Black Matrix".
One serious drawback of the standard shadow mask tube is the appearance of its picture viewed in daylight conditions or high ambient lighting conditions. In the standard shadow mask tube there are two principal factors contributing to this deficiency. Firstly, in order to accommodate beam landing errors the diameters of the phosphor dots are made larger than those of the beams, and secondly the spaces surrounding these dots is covered by a highly reflective aluminum coating. These two factors together mean that approximately 10% of the screen area is never excited by any electron beam but will nevertheless diffusely reflect ambient light and hence impair the appearance of the picture. In order to reduce this effect to acceptable limits a dark-tint face plate is used. This reduces, by a certain factor, the brightness of the reflected ambient light; but it also reduces, though only by half that factor, the brightness of the picture. Thus although there is a net improvement in appearance, the general level of picture brightness is reduced. This effect can be compensated by driving the phosphor harder, but this reduces the life of the tube. Taking this fact into consideration a face plate with approximately 50% transmission is generally considered a reasonable compromise.
A novel approach to the problem is firstly to arrange to accommodate beam landing errors by making the electron beams larger than the visible portions of the dots, and secondly to fill the space between these portions with a non-reflecting coating.
With this arrangement, if only 50% of the screen area is excited by electron beams and the remainder is substantially non-reflecting, then an 80% transmission face plate could be used, thereby providing a 54% increase in brightness with a 30% better contrast ratio between the picture and the reflected ambient light.
The arrangement can be achieved in principle by producing an appropriate pattern of holes in a black coating on the inside of the tube facce. The holes are made undersize on the standard phosphor dots which are subsequently superimposed on these holes. The diameters of the electron beams are again standard size but beam landing errors are accommodated by virtue of the fact that the effective light emitting area of each phosphor dot is restricted to that portion lying in its associated hole.
A critical step in this process is the production of the pattern of undersize holes. Since a shadow mask is unique to a tube this pattern can only be achieved by a technique which involves the temporary reduction in size of the apertures of a shadow mask.
Two methods have previously been proposed. One of these involves making the shadow mask with undersize holes which are subsequently enlarged by etching after it has been used to make the pattern of undersize holes in the black coating. The other method involves using a shadow mask with standard size holes which is then plated with a different metal to reduce their size. After the pattern of undersized holes in the black coating has been made the holes of the shadow mask are opened out again to their original size using a selective etch which will remove the plated layer, but which will not attack the underlying material from which the shadow mask is constructed. Both these methods are complicated by the fact that the enlargement of the holes has to be performed after the shadow mask has been fitted to its supporting frame and formed. It will be realized that there is a risk of trapping the etching solution between the mask and its frame which may cause contamination within the completed tube. A further disadvantage of the plating method is that it is time consuming and expensive on materials. Yet another disadvantage of methods involving the use of etching solutions is that they are liable to remove the oxide layer created during the forming of the shadow mask. If this oxide layer has to be recreated by a further heat treatment there is a serious risk that the shadow mask will slightly change its shape and thus lose its compatibility with the deposited pattern of phosphor dots.

Reducing aperture-size of shadow mask in painting black matrix CRT screen

International Standard Electric Corporation


A photochromic coating composition contains a silicon-containing precondensate derived from a hydrolysable silane containing a polymerizable functional group on a hydrolysis-stable radical, a photochromic dye, a stabilizer, and nanoscale particles. The coating composition, when applied to transparent plastic and glass substrates and cured, gives a coating having high light stability and good scratch resistance.

The present invention relates to photochromic coating compositions and to substrates provided therewith. In particular, the present invention relates to photo-chromic coating compositions which comprise, as essential components, a silicon-containing precondensate, at least one photochromic dye and at least one stabilizer (for example an antioxidant and/or a UV absorber). These coating compositions are particularly suitable for providing substrates made from (preferably transparent) plastics and mineral glasses with a hard, scratch-resistant coating having a long-term photochromic action.
Photochromic components or elements having excellent photochromic behaviour, in particular over long periods, are nowadays employed in a wide variety of areas, the best-known being the area of photochromic spectacle lenses. At present, these photochromic substrates are produced by providing corresponding plastics with organic photochromic substances by very complex and expensive processes. In general, such processes are not suitable for use on a large scale and in a wide variety of areas. Furthermore, C. Sanchez, in J. Mater. Chem. 7(1) (1997), 61-65, describes the incorporation of spiropyrans and spirooxazines into organic/inorganic matrices of diethoxydimethylsilane/zirconium propoxide and methyldiethoxysilane/triethoxysilane, but without investigating the light stability of these systems.
It has now been found, in accordance with the invention, that photochromic coating compositions which are simple and inexpensive to produce on the basis of certain silicon-containing precondensates, photochromic dyes and stabilizers are suitable for providing corresponding substrates with a remarkably hard and scratch-resistant coating which exhibits long-term photochromicity. Coating compositions of this type are suitable for a large number of applications, such as, for example, photochromic spectacle lenses, lenses for sunglasses, visors and ski goggles, but also for glazing of all types, in particular for decorative needs, buildings, automobiles and aircraft, in which a photochromic effect is desired (and which are exposed to varying irradiation with light (in particular sunlight)).
Accordingly, the present invention provides a photochromic coating composition which comprises, as essential components:
(a) a silicon-containing precondensate derived from at least one hydrolysable silane A containing at least one hydrolysis-stable radical R which has a functional group X which is capable of undergoing a thermally and/or photochemically induced (optionally catalysed) polymerization reaction, and optionally from one or more additional hydrolysable compounds of elements from the group consisting of Si, Al, Ti, Zr, Ta, Nb, Sn, Zn, W and Ge;
(b) at least one photochromic dye; and
(c) at least one stabilizer, preferably selected from antioxidants and UV absorbers.
The above silane A usually contains at least one (and preferably a single) group X, which is an epoxide, mercapto or (meth)acrylyl group.
It is furthermore particularly preferred for the silane A to be selected from compounds of the following general formula (I):
R1xSiR3(3xe2x88x92x)Rxe2x80x83xe2x80x83(I)
in which the radicals R1 are identical or different (preferably identical) and are selected from halogen atoms (in particular Cl and Br), (preferably C1-4-)alkoxy groups and (preferably C2-6-)acyl groups (the groups R1 are particularly preferably methoxy or ethoxy groups); the radicals R3 are a (preferably unsubstituted) alkyl or aryl radical (for example methyl, ethyl, propyl, butyl or phenyl), and x is 1, 2 or 3 (preferably 2 or 3).
The radical(s) R is (are) preferably selected from those of the following general formulae (II) and (III):
in which R2 is hydrogen or methyl, and n is an integer from 1 to 6, preferably from 2 to 4, and in particular 3. However, the radical(s) R may also contain other functional groups and may optionally be fluorinated.
Specific examples of silanes A of this type are 3-glycidoxypropyltri(m)ethoxysilane and 3-(meth)acryloxypropyltri(m)ethoxysilane.
The photochromic dye (b) is preferably selected from the group consisting of the spirooxazines, spiropyrans, naphthopyrans (chromenes), fulgides and dihydroindolizines. Particular preference is given to photochromic dyes from the group consisting of the spirooxazines and naphthopyrans.
Suitable stabilizers which can be employed as component (c) in the present coating composition are all compounds which are capable of protecting the photochromic dyes (b) in a suitable manner against attack (for example decomposition) by radiation (in particular UV radiation) and/or (aggressive) chemical substances (oxygen, ozone, free radicals, etc.). Preferred examples thereof are antioxidants and UV absorbers.
The antioxidants which can be used as stabilizers in the coating composition according to the invention include the compounds known to the person skilled in the art as antioxidants. However, the antioxidant employed in accordance with the invention is preferably selected from the group consisting of phenols, hydroquinones, pyrocatechols and aromatic amines which are substituted by sterically hindered groups, and organic phosphites and phosphonates. The term xe2x80x9cphenolxe2x80x9d here is intended to cover not only monocyclic phenols, but also bicyclic (bisphenols), tricyclic (trisphenols) and polycyclic phenols and naphthols.
The UV absorbers which can be employed as stabilizers in the coating composition according to the invention include the compounds which are known to the person skilled in the art as UV absorbers. Preferred UV absorbers include derivatives of benzophenone, whose substituents (for example hydroxyl and/or alkoxy groups) are preferably in the 2- and/or 4-position; substituted benzotriazoles, 3-phenyl-substituted phenylacrylates (cinnamic acid derivatives) and salicylates.
Further UV absorbers which are preferred in accordance with the invention are natural products, such as 3-(5-imidazolyl)acrylic acid (urocanic acid) and ergosterol.
According to a preferred embodiment of the present invention, the coating composition according to the invention, besides the above essential components (a), (b) and (c), also comprises nanoscale particles, which are preferably selected from the group consisting of the oxides, nitrides, carbides, silicides, borides and carbo-nitrides of Al, Si, Ti, Zr, Hf, W, Ga, Nb, Ta, Sn, Zn and Ge. In the present connection, the term xe2x80x9cnanoscale particlesxe2x80x9d is taken to mean particles having a mean particle size of not greater than 200 nm, preferably not greater than 100 nm and particularly preferably not greater than 50 nm (for example up to 30 nm). The nanoparticles can also be employed in surface-modified form in order to prevent agglomeration of the particles. The surface modification is carried out here, for example, using epoxy-, amino-, mercapto- or (meth)acrylate-functional silanes; see, for example, DE-A-195 40 623.
Particularly preferred nanoscale particles for use in the present invention are those comprising SiO2 (for example silica sols).
Nanoscale particles of this type are preferably used, if at all, in amounts of from 2 to 100% by weight of the precondensate (a) employed, a proportion of from 5 to 50% by weight being even more preferred.
Components (a), (b) and (c) of the present coating composition are preferably present in such amounts, based on the total weight of these components, that component (b) makes up from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, and component (c) makes up from 0.1 to 5% by weight, preferably from 0.5 to 2.5% by weight.
The present invention is explained in greater detail below with reference to preferred embodiments.
As already mentioned above, the silicon-containing precondensate to be employed in the coating composition according to the invention is preferably derived from at least one hydrolysable silane A containing an epoxide, mercapto or (meth)acrylate group X.
The epoxide-based formulation comprises a precondensate derived from a silane A containing an epoxide group X, and optionally one or more other components, which are preferably selected from purely organic compounds containing an epoxide group (preferably containing two or more epoxide groups), additional organic compounds containing functional groups which are reacted with epoxide groups, hydrolysable silanes containing alkyl or fluorinated alkyl groups, additional metal oxides, the abovementioned nanoscale particles, spacers and crosslinking agents. A surfactant is also optionally added to the coating formulation.
The most preferred epoxide-based silane A is 3-glycidoxypropyltrimethoxysilane. Specific examples of other preferred silanes containing an epoxide group are 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyldimethylethoxysilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3,4-epoxybutyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.
Preferred examples of the abovementioned purely organic compounds containing an epoxide group are bisphenol A diglycidyl ether, 2,2-bis(4-(2,3-epoxypropoxy)cyclohexyl)propane, 1,4-butanediol diglycidyl ether, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 4-epoxyethyl-1,2-epoxycyclohexane, ethylene glycol diglycidyl ether, triglycidyl glycerol, cresyl glycidyl ether, neopentyl glycol diglycidyl ether, 1-(2,3-epoxypropoxy)-4-[N,N-bis(2,3-epoxypropyl)amino]benzene, bis(4-[N,N-bis(2,3-epoxypropyl)amino]phenyl)methane, triglycidyl isocyanurate, phenyl glycidyl ether, 5,5-dimethyl-1,3-bis(2,3-epoxypropyl)-2,4-imidazolidinedione, heptafluoropropyl-1,3-bis[2-(2,3-epoxypropoxy)hexafluoro-2-propyl]benzene, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-meta-dioxane, styrene oxide, butadiene dioxide, divinylbenzene dioxide, diglycidyl ether, poly(propylene glycol) bis(2,3-epoxypropyl ether), bis(3,4-epoxycyclohexyl) adipate, 3-bis[(2,3-epoxypropoxymethyl)methoxy]-1,2-propanediol, 1,4-bis(hydroxymethyl)cyclohexane bis(2,3-epoxypropyl ether) and hexahydrophthalic acid diglycidyl ether. Particularly preferred compounds from said group are cycloaliphatic or aliphatic compounds, such as 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and bis-3,4-epoxycyclohexyl adipate. These compounds are particularly preferred owing to their improved UV stability compared with aromatic compounds.
Organic compounds, such as, for example, phenols, can be introduced into the coating composition as spacers. The most frequently employed compounds for this purpose are bisphenol A, (4-hydroxyphenyl)adamantane, hexafluorobisphenol A, 2,2-bis(4-hydroxyphenyl)perfluoropropane, 9,9-bis(4-hydroxyphenyl)fluorenone, 1,2-bis-3-(hydroxyphenoxy)ethane, 4,4xe2x80x2-hydroxyoctafluorobiphenyl and tetraphenolethane.
The modification with alkyl-substituted alkoxysilanes can be carried out, for example, using the following compounds: tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, cyclohexyltrimethoxysilane, cyclopentyltrimethoxysilane, ethyltrimethoxysilane, phenylethyltrimethoxysilane, phenyltrimethoxysilane, n-propyltrimethoxysilane, cyclohexylmethyldimethoxysilane, dimethyldimethoxysilane, diisopropyldimethoxysilane, phenylmethyldimethoxysilane, phenylethyltriethoxysilane, phenyltriethoxysilane, phenylmethyldiethoxysilane and phenyldimethylethoxysilane.
Fluorinated silanes are introduced into the coating composition in particular if a low surface energy of the coating, which results in dirt- and water-repellent properties, is desired. Examples of silanes which are suitable for this purpose are those which contain directly silicon-bonded, fluorinated alkyl radicals having at least four carbon atoms, the carbon atoms in the xcex1- and xcex2-position to the silicon preferably carrying no fluorine atoms, for example (tridecafluoro-1,1,2,2-tetrahydrooctyl)methyldiethoxysilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl)triethoxysilane, (heptadecafluoro-1,1,2,2-tetrahydrodecyl)methyldiethoxysilane and (heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane.
Examples of other hydrolysable compounds which can be used for the preparation of the silicon-containing precondensate (a) are, in particular, the alkoxides (preferably containing C1-4-alkoxy groups) of aluminium, titanium, zirconium, tantalum, niobium, tin, zinc, tungsten and germanium. Specific examples of compounds of this type are aluminium sec-butoxide, titanium isopropoxide, titanium propoxide, titanium butoxide, zirconium isopropoxide, zirconium propoxide, zirconium butoxide, zirconium ethoxide, tantalum ethoxide, tantalum butoxide, niobium ethoxide, niobium butoxide, tin t-butoxide, tungsten(VI) ethoxide, germanium ethoxide, germanium isopropoxide and di-sec-butoxyaluminotriethoxysilane.
In particular in the case of the more reactive alkoxides (for example of Al, Ti, Zr, etc.), it may be advisable to employ these in complexed form, examples of suitable complexing agents being, for example, unsaturated carboxylic acids and xcex2-dicarbonyl compounds, such as, for example, methacrylic acid, acetylacetone and ethyl acetoacetate.
The incorporation already mentioned above of nanoscale inorganic particles into the coating composition results in improved scratch resistance and stability of the resultant coating and also allows the production of relatively thick coatings. In addition, the refractive index of the coating can be adjusted in this way. Examples of nanoscale particles which are suitable in accordance with the invention are those comprising SiO2, ZrO2, TiO2, HfO2, GeO2, Nb2O5, Ta2O5, SnO2, Al2O3, ZnO and GeO2, those comprising SiO2 being particularly preferred.
The epoxide-based coatings are preferably cured thermally. Crosslinking agents which are suitable for this purpose are, in particular, imidazoles, amines and acid anhydrides. If imidazoles are to be employed as crosslinking agent, 1-methylimidazole is particularly preferred. Other preferred examples of imidazole crosslinking agents are 2-methylimidazole and 2-phenylimidazole. Examples of crosslinking agents from the group consisting of primary, secondary and tertiary amines are ethylenediamine, diethylenetriamine, triethylenetetramine, 1,6-diaminohexane, 1,6-bis(dimethylamino)hexane, tetramethylethylenediamine, N,N,Nxe2x80x2,Nxe2x80x3,Nxe2x80x3-pentamethyldiethylenetriamine, 1,4-diazabicyclo[2.2.2]octane, cyclohexane-1,2-diamine, 2-(aminomethyl)-3,3,5-trimethylcyclopentylamine, 4,4xe2x80x2-diaminocyclohexylmethane, 1,3-bis(aminomethyl)cyclohexane, bis(4-amino-3-methylcyclohexyl)methane, 1,8-diamino-p-menthane, 3-(aminoethyl)-3,3,5-trimethylcyclohexylamine (isophoronediamine), piperazine, piperidine, urotropin, bis(4-aminophenyl)methane and bis(4-aminophenyl) sulphone. The amines employed as crosslinking agent may also be functionalized with silanes. Examples thereof are N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, aminopropyltrimethoxysilane and aminopropyltriethoxysilane. In addition, boron trifluoride adducts of amines, such as, for example, BF3/ethylamine, can be employed. Furthermore, the crosslinking and curing can be accomplished with the aid of acid anhydrides (preferably in combination with tertiary amines), such as methylbicyclo[2.2.1]heptene-2,3-dicarboxylic anhydride, hexahydronaphthylenedicarboxylic anhydride, phthalic anhydride and 1,2-cyclohexanedicarboxylic anhydride.
As mentioned above, a surfactant can also be added to the coating formulation. This prevents aggregation of the dye molecules in the coating. Furthermore, it is of course also possible to add organic solvents to the coating composition in order to match its viscosity to the requirements of the coating method employed (for example dipping, spraying, brushing, spin coating, etc.).
A further preferred coating composition is one based on acrylate or methacrylate, i.e. one which comprises a precondensate based on a silane A containing a (meth)acrylate group X. A coating composition of this type can be prepared using the same additional materials as already described above in connection with the epoxide-based coating composition.
Specific (and preferred) examples of silanes A containing a (meth)acrylate group X are 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 2-(meth)acryloxyethyltrimethoxysilane and 2-(meth)acryloxyethylmethyldimethoxy-silane. Of these, 3-methacryloxypropyltrimethoxysilane is particularly preferred.
Example of components which can be used as spacers in the case of (meth)acrylate-based coating compositions are bisphenol A bisacrylate, bisphenol A bismethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, diethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, 2,2,3,3-tetrafluoro-1,4-butanediol diacrylate and dimethacrylate, 1,1,5,5-tetrahydroperfluoropentyl 1,5-diacrylate and -dimethacrylate, hexafluorobisphenol A diacrylate and dimethacrylate, octafluorohexanediol 1,6-diacrylate and -dimethacrylate, 1,3-bis(3-methacryloxypropyl)tetrakis(trimethylsiloxy)disiloxane, 1,3-bis(3-acryloxypropyl)tetrakis(trimethylsiloxy)disiloxane, 1,3-bis(3-methacryloxypropyl)tetramethyldisiloxane and 1,3-bis(3-acryloxypropyl)tetramethyldisiloxane.
The (meth)acrylate-based coating compositions are preferably cured with the aid of thermal catalysts. Examples thereof are the conventional thermal polymerization initiators, such as, for example, azobisisobutyronitrile, diacyl peroxides (for example dibenzoyl peroxide and dilauroyl peroxide), peroxodicarbonate, alkyl peresters, perketals, alkyl or aryl peroxides, ketone peroxides and hydroperoxides.
Component (a) of the coating composition according to the invention can be obtained, for example, by a process as described, for example, in xe2x80x9cJournal of Sol-Gel Science and Technologyxe2x80x9d (1994), Volume 2, pp. 635-639.
The nanoscale particles preferably employed can be added in the form of wettable powders or in the form of colloidal suspensions and in surface-modified form.
It has been found in accordance with the invention that the switching kinetics of the conversion from the colourless state into the coloured state of the photochromic materials can be controlled (in general slowed) via the concentration of the crosslinking agent and/or through variation of the type of crosslinking agent or spacer used.
In order to achieve effective retardation of the switching kinetics, from 1 to 50 mol %, preferably from 10 to 30 mol %, of crosslinking agent are usually employed per functional group of the network-forming components and spacers.
As an alternative to or in combination with the crosslinking agent concentration, the switching kinetics of the photochromic dyes in the matrix can be adjusted through variation of the type of crosslinking agent and/or type of spacer (polar). In this case, stepless adjustment up to multiple values are achieved in comparison with the kinetics in ethanolic solution.
The term xe2x80x9cpolar spacersxe2x80x9d here is taken to mean organic compounds containing at least two functional groups (epoxide, (meth)acrylyl, mercapto, vinyl, etc.) at the molecule ends, which, owing to the incorporation of aromatic or heteroaromatic groups (such as phenyl, benzyl, etc.) and heteroatoms (such as O, S, N, etc.), have polar properties and can undergo a polar interaction with the photosubstances.
The polar spacers are usually employed in a molar ratio to the network-forming components of up to 3:1, preferably of up to 1:1.
Examples of the abovementioned polar spacers are the following:
a) based on epoxide:
poly(phenyl glycidyl ether)-co-formaldehyde, bis(3,4-epoxycyclohexylmethyl) adipate, 3-[bis(2,3-epoxypropoxymethyl)methoxy]-1,2-propanediol, 4,4-methylenebis-(N,N-diglycidylaniline), bisphenol A diglycidyl ether, N,N-bis(2,3-epoxypropyl)4-(2,3-epoxypropoxy)aniline, 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexanecarboxylate), glycerol propoxide triglycidyl ether, diglycidyl hexahydrophthalate, tris(2,3-epoxypropyl) isocyanurate, poly(propylene glycol) bis(2,3-epoxypropyl ether), 4,4xe2x80x2-bis(2,3-epoxypropoxy)biphenyl
b) based on methacrylate and acrylate:
bisphenol A dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-diisopropenylbenzene, divinylbenzene, diallyl phthalate, triallyl 1,3,5-benzenetricarboxylate, 4,4xe2x80x2-isopropylidenediphenol dimethacrylate, 2,4,6-triallyloxy-1,3,5-triazine, 1,3-diallylurea, N,Nxe2x80x2-methylenebisacrylamide, N,Nxe2x80x2-ethylenebisacrylamide, N,Nxe2x80x2-(1,2-dihydroxyethylene)bisacrylamide, (+)-N,Nxe2x80x2-diallyltartaramide, methacrylic anhydride, tetraethylene glycol diacrylate, pentaerythritol triacrylate, diethyldiallyl malonate, ethylene diacrylate, tripropylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol trimethacrylate, allyl methacrylate, diallyl carbonate, diallyl succinate, diallyl pyrocarbonate.
The preferred photochromic compounds (b) employed for the purposes of the present invention are photochromic compounds which belong to the class of the spirooxazines or naphthopyrans (chromenes).
Examples of particularly preferred photochromic compounds which belong to the class of the spirooxazines are those of the following general formula (IV):
in which
R1 and R2, identical to or different from one another, are hydrogen, halogen (for example chlorine, bromine or fluorine), C1-5-alkoxy, nitro, cyano or linear or branched C1-5-alkyl (optionally with one or more substituents from the group consisting of the halogen atoms, such as chlorine, bromine and fluorine, C1-5-alkoxy, C1-5-alkylthio, C1-5-carboxyalkyl and cyano groups); and
R1 and R2 can be linked to any of the 4-, 5-, 6- and 7-positions of the indoline unit;
R3 and R4, independently of one another, are a linear or branched C1-5-alkyl group, a phenyl group or a benzyl group; or
R3 and R4, together with the carbon atom to which they are linked, can form a C4-8-cycloalkyl group;
R5 is a phenyl group, benzyl group or allyl group or a linear or branched C1-5-alkyl group, which may optionally be substituted by one or more halogen atoms (for example chlorine, bromine or fluorine) and/or one or more C1-5-alkoxy groups, C1-5-alkylthio groups, C1-5-carboxyalkyl groups or cyano groups;
R6 is a hydrogen atom, halogen atom (such as, for example, chlorine, bromine or fluorine) or a group selected from the following: C1-5-alkoxy groups, C1-5-alkylthio groups, C1-5-carboxyalkyl groups, nitro groups and cyano groups; and linear or branched C1-5-alkyl groups, which may optionally be substituted by one or more halogen atoms, such as, for example, chlorine, bromine or fluorine, and/or one or more C1-5-alkoxy groups, C1-5-alkylthio groups, C1-5-carboxyalkyl groups and cyano groups; or
R6 is a fused aromatic or heterocyclic ring; and
R6 can be located in any of the 7xe2x80x2-, 8xe2x80x2-, 9xe2x80x2- and 10xe2x80x2-positions of the naphthalene radical if it is not hydrogen or a fused aromatic or heterocyclic ring;
R7 is hydrogen or an xe2x80x94NR8R9 group, in which R8 and R9, independently of one another, are a hydrogen atom, a linear or branched C1-5-alkyl group, a phenyl group or a benzyl group; or R8 and R9, together with the nitrogen atom to which they are linked, form a monocyclic or polycyclic structure having 5 to 12 members, which optionally contains a further heteroatom selected from nitrogen and oxygen; and X is CH or N.
Preferred photochromic compounds from the class of the spirooxazines which are suitable for use in the present invention are those containing the following substituents in the general formula (IV):
R1 and R2, independently of one another, are hydrogen or a methyl group;
R3 and R4 are both a methyl group or together form a cyclohexyl group;
R5 is a methyl group;
R7 is a hydrogen atom or an xe2x80x94NR8R9 group, in which R8 and R9, together with the nitrogen atom to which they are linked, form a piperidyl, morpholyl, pyrrolidyl or hexamethyleneamine ring;
R6 is a hydrogen atom, a nitro group or an oxomethyl, oxoethyl or oxophenyl group; and
X is CH.
Specific examples of compounds of the above formula (IV) are 1,3,3-trimethyl-6xe2x80x2-piperidinospiro[indolino-2,3-(3H)naphtho(2,1-b)(1,4)oxazine], which is available under the trade name Variacrol Red PNO from Great Lakes Chemical Italia S.r.l. and has the following formula:
and 1,3,3-trimethylspiro[indolino-2,3-(3H)naphtho(2,1-b)(1,4)oxazine], which is available under the tradename Variacrol Blue A from Great Lakes Chemical Italia S.r.l. and has the following formula:
Examples of photochromic compounds which belong to the class of the chromenes (naphthopyrans) and are useful for the purposes of the present invention are those having the following general formula (V):
in which
R10 and R11, independently of one another, are a hydrogen atom, a linear or branched C1-5-alkyl group, a phenyl group, which may be substituted by 1 to 5 halogen atoms (for example fluorine, chlorine or bromine), or a cyclopropyl group; or R10 and R11 together form an alicyclic C5- or C6-group or an adamantyl group.
Preferred photochromic compounds from the above class of the chromenes are those of the general formula (V) in which R10 and R11 are an unsubstituted phenyl group.
A specific example of a photochromic compound from the class of the chromenes having the above formula (V) is 2,2-diphenyl-5,6-benzo(2)chromene, which is available under the tradename Variacrol Photo L from Great Lakes Chemical Italia S.r.l. and has the following formula:
Antioxidants and UV absorbers which can be employed in accordance with the invention as stabilizers have already been mentioned above. Specific examples thereof are 2,6-di-tert-butyl-4-methylphenol (BHT), bis(3,5-di-tert-butyl-4-hydroxyphenyl)methane (BDPM), tetrafluorohydroquinone, ergosterol and urocanic acid and (optionally) substituted triphenylphosphites (for example trinonylphenyl phosphite (TNPP)).
It is of course also possible for other stabilizers to give particularly desirable results, depending on the specific circumstances. Examples of such stabilizers are N,Nxe2x80x2-disubstituted p-phenylenediamines, diphenylamine derivatives, aminophenol derivatives, phenylbenzylureas, aldehyde-amine condensation products (for example heterocyclic compounds), ketone-amine condensation products (for example heterocyclic compounds), sulphur compounds, such as mercaptans (alkylmercaptans, mercaptobenzimidazole), thioethers (thiobisphenols, thiobisalkanecarboxylic acid esters), disulphides (for example dialkyl sulphides), dithiocarbamates, derivatives of dithiophosphoric acid, thiobisphenols, sulphur-containing amines, tocopherol, octyl and dodecyl gallate, ascorbic acid, lactic acid, citric acid and tartaric acid and their salts, and the like.
The preparation of a photochromic coating composition according to the invention will be illustrated below with reference to a specific example using 3-glycidoxypropyltrimethoxysilane as silane A.
The preparation begins with a 2-step pre-hydrolysis of 3-glycidoxypropyltrimethoxysilane (GPTMS) using dilute hydrochloric acid at room temperature. A solution of bisphenol A in ethyl alcohol is added to the pre-hydrolysed GPTMS at room temperature with stirring, after which 1-methylimidazole is added. The mixture is then stirred at room temperature for a further 1 hour. After the addition of the photochromic compound, the stabilizer and a surfactant in order to achieve better dispersion of the photochromic compound, the mixture is stirred for a further 30 minutes, which gives a solution which is suitable for coating of plastic and glass articles.
If organic epoxide compounds, other silane compounds, alkoxides of elements other than silicon and/or inorganic nanoscale particles and the like are to be additionally introduced into the coating composition, modified synthetic methods are employed, if necessary. For example, additional silane components can, with the exception of fluoroalkylsilane compounds, be subjected to pre-hydrolysis together with the epoxide-based silanes. Additional epoxides, such as bis(3,4-epoxycyclohexyl) adipate or 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate, and organic compounds other than bisphenol A can then be added. If trialkoxysilanes containing a fluorinated alkyl group are to be introduced into the coating composition, these silanes are preferably added after the other silane components have been prehydrolysed. Two phases thus form. The amount of water necessary for semi-stoichiometric hydrolysis of the fluorinated alkoxysilanes is then added, and the mixture is stirred at least until it only exhibits one phase. This process ensures homogeneous distribution of the fluorinated silane and is particularly recommended since fluorinated alkoxysilanes generally hydrolyse more quickly than the other silane components employed. If desired, alkoxides of other elements can be added to the coating composition. In the case of alkoxides which hydrolyse more rapidly than comparable silicon compounds, these are preferably employed in the form of complexed precursors in order to prevent precipitation of the corresponding oxides during the hydrolysis. As already mentioned above, complexing agents which are suitable for this purpose are, for example, methacrylic acid, acetylacetone and ethyl acetate.
Nanoscale particles, such as, for example, those mentioned above, can be added to the coating composition in order to provide the coating with additional hardness. In order to prevent agglomeration of the particles in the coating sol, the surfaces of the particles are preferably modified by means of suitable stabilizers. Preferred nanoscale particles introduced into the coating composition are those which are commercially available in the form of wettable powders or colloidal solutions in alcohols. Particularly suitable for the aims of the present invention are SiO2 particles in methanol and isopropanol, which are commercially available from Nissan Chemical (MA-ST, IPA-ST). The nanoscale particles are preferably added to the coating composition after pre-hydrolysis of silane A. The alcoholic SiO2 sol, to which an additional sol stabilizer (for example tetrahexylammonium hydroxide) has been added, is mixed with the pre-hydrolysed epoxysilane, and all or some of the solvent is then stripped off under reduced pressure. In a preferred procedure, a mixture of nanoscale particles in silane A (for example based on epoxide) is firstly prepared separately, and the suitable amount of the nanoscale particles in this form is then added to the pre-hydrolysed silane component(s) of the coating composition.
The coating compositions applied to the substrates can be cured by means of a multiplicity of possible curing agents, as already indicated above. In the case of epoxysilanes, amines are preferred since they result in lower curing temperatures compared with anhydrides. If imidazoles are employed as curing agent, 1-methyl-imidazole is particularly preferred. Further curing agents which are particularly suitable for the purposes of the present invention are aliphatic and cycloaliphatic amines. Aliphatic amines containing primary amino groups are very reactive and result in short pot lives. For this reason, cycloaliphatic amines, such as isophoronediamine or menthanediamine, and tertiary amines, such as tetramethylethylenediamine, are particularly preferred. Since these compounds are more reactive than the imidazoles, they are wherever possible not added to the coating composition until just before the coating operation.
If desired, the coating formulation can be diluted with solvents, for example alcohols, such as methanol and ethanol, or tetrahydrofuran, in order to match the viscosity of the coating composition to the requirements of the specific coating process employed.
Naturally, in the case of silanes A containing (meth)acrylate groups and other silanes containing suitable groups X, analogous processes to those just outlined for the case of the epoxysilanes can be employed for the preparation of the coating composition.
As already mentioned above, the coating compositions prepared are applied to the corresponding substrates in the manner which is conventional to the person skilled in the art and subsequently cured thermally and/or photochemically, depending on the presence of functional groups and the curing catalysts. Particular preferred coating methods are dipping, roll coating, spray coating and spin coating.
The coating composition according to the invention is particularly suitable for providing (preferably transparent) substrates made from plastic or glass with a photochromic coating. Examples of such substrates are spectacle lenses, sunglasses, optical lenses, building, automobile and aircraft glazing, visors for helmets (for example for motorcyclists and skiers). Further suitable substrates are paper, textiles, metal, wood, stone and ceramic.
The coating compositions according to the invention are more specifically suitable, for example, for the following applications:
for glazing and windows of means of transport of all types (ships, rail vehicles, automobiles, aircraft), as complete or partial coating and on laminatable films which can be applied to the windows;
for interior and exterior architectural glazing made from glass and plastic, including room dividers (computer workstations, cultural centres, such as museums, concert halls and exhibition rooms, public buildings, private dwellings, greenhouses);
coatings on films of all types (roller blinds, laminatable films, packaging material for, for example, gifts and plants, best-by date seals in packaging);
for visual aids and as sight and dazzle protection (spectacles, sunglasses, sports goggles, helmet visors, contact lenses, magnifying glasses, reading aids);
for marking paper (banknotes, documents), identity cards, credit and cheque cards and other valuables;
for optical elements with self-regulating transmission (lenses, graduated lenses, filters, lenses for photographic equipment, telescopes, video cameras, film cameras);
as decoration elements on lamps, textiles, such as clothing, textile applications outside, such as sunshades and tents, furniture, sanitary articles, toys, joke articles, facades, vehicles (photochromic paint);
as decorative elements on wall coverings, paints, stage sets;
as decorative elements in the paper industry (greetings cards, letterheads, labelling, attachment of advertising;
for products made from ceramic and porcelain (tiles, crockery, ornamental figures);
in art (paintings, pictures, sculptures, design of special effects);
as decorative elements for ornaments and jewellery (photochromic wigs, back-lining of gemstones or imitation gemstones, fashion jewellery, such as, for example, glass pearl necklaces);
in cosmetics (hair lacquer, nail varnish, lipstick);
in shops for displays, special offers, etc.;
as interlayer between two glass sheets;
for temporary masks.

Photochromic coating composition comprising nanoscales particles and process for providing substrate coated with the same

Institut fxc3xcr Neue Materialien gemeinnxc3xctzige GmbH


A human computer interface system capable of providing real time context intelligence in relation to automatically recognized input signals. The system provides for the real time monitoring of operator and/or user inputs providing intelligent support by way of text, electronically presented data, information and speech outputs.

1. Field of the Invention
This is invention relates to the field of human computer interfacing and more particularly but not exclusively to intelligent systems and their ability to process botch voice and data inputs.
2. Discussion of Prior Art
State of the art applications and database interrogation methods usually comprise the use of trained operators utilizing menu driven interface systems to retrieve the required data or information on demand. Such systems typically require the operator to have knowledge of the access requirements of a number of databases and in most cases further constrains the operator to using and having access to only one such database at a time.
In areas such as Telephone Call Centres, typically used by companies for customer query and complaint processing, trained operators are required to ask predetermined questions of the callers to enable them to then manually access whichever particular database is required, in order to identify such features as part numbers, makes and/or models for use in processing the query or complaint. For example, a typical call center operator may be required to respond to customer requests for information over a range of differing company products, namely telephones, washing machines, televisions, audio equipment etc. The operator would therefore have to quickly establish which particular type of product the caller is referring to following by the make, model number, serial number and possibly date of purchase, these types of information most probably being stored on more than one database. The requirement to switch between a range of databases using a keyboard and/or mouse and conduct a conversation using a predetermined set of closely worded questions can be an arduous task for a call center operator and our invention would significantly reduce the operator work load and call time per transaction.
Numerous other applications where access to a range of databases is required which currently use manual operator access may include logistics and support, physical security and tasks such as those performed by ships"" captains when steering vessels, pilots and airborne engineers.
European Patent Application No. 92119615.0 discloses a speech dialogue system for facilitating human-computer interaction. This speech dialogue based invention, although having a human-computer interaction role, does not perform the function of assisting a human operator in his or her tasks but is designed to replace a human operator. The invention allows a human to speak to a machine, and through a speech recognition system a response to input speech is formulated and an output made according to the understood semantic content of the input speech. The understanding of a semantic content of an input speech from the user is made by detecting keywords in the input speed with the keywords in the input speed being limited in advance in accordance with the needs of the overall system.
The speech dialogue system therefore assists a customer by replacing a human operator and not by supporting an operator throughout a series of transactions. Our invention utilizes a human computer interface system and an intelligence system which enables real time analysis of operator and/or customer inputs (keyboard, mouse, speech etc.) and provides a reasoning facility designed specifically to support an operator by navigating a xe2x80x9crichxe2x80x9d data domain (one or more databases) in response to contextual keywords and phrases provided by a automatic speech recognition system.
Our invention provides apparatus and a method of providing real-time context intelligence of automatically recognized key words/phrases, for use in hands free searches of simple and more complex databases. Additionally it provides a flexible and powerful approach to improving current Call Centre Software support by integrating a fully functional Human Computer Interface (HCI)System with an Intelligent system and allowing these to be further integrated with an existing software Application.
Accordingly there is provided a human-computer interface system, comprising user interface and display means for both inputting speech and data and outputting visual and speech responses, human-computer interface means for recognition of a user input and subsequent passing of recognized inputs to an intelligence systems means, and for supplying output signals to the user interface and display means, intelligence system means for correlating the recognized user input with the context of the operation being performed by the user, based on an intelligent assessment of the context of the user operation, and based on such assessment, sending output signals to the user interface and display means which may comprise information or data retrieved from an applications or database.
According to another aspect of the invention there is provided a method a method of providing real time context intelligence in relation to automatically recognized input signals whereby information and/or data inputted from a user interface and display means is recognized by a human-computer interface means such that it can be passed to an intelligence system means whereby the recognized user input data and information is correlated with the context of the operation being performed by the user, and based on an intelligent assessment of the context of the user operation, output signals are sent back to the user interface and display means, said output signals capable of comprising information or data retrieved from applications or database.

Intelligent human/computer interface system

Bae Systems (Land and Sea Systems) Limited


The present invention is directed to a composition comprising a hydrogenated block copolymer of a vinyl aromatic and conjugated diene polymer, having a lamellar morphology and high aromatic hydrogenation level.

The present invention is directed to a composition of a hydrogenated block copolymer of a vinyl aromatic monomer and a conjugated diene monomer.
Various hydrogenated block copolymer compositions have been disclosed in previous applications, such as in copending applications Ser. No. 09/330,520 and Ser. No. 09/330,663, filed Jun. 11, 1999. Additionally, fabricated articles produced from such hydrogenated block copolymers have been disclosed in copending applications Ser. Nos. 09/575,063 and 09/575,062, filed May 19, 1999. However, a combination of good impact strength, processability and surface appearance is difficult to achieve in some applications of these polymers, such as in extruded sheet.
Therefore, there remains a need for hydrogenated block copolymer compositions having a superior balance of impact strength, processability and surface aesthetics which can be advantageously applied in extruded sheet applications.
It has been surprisingly discovered that an excellent balance of impact strength, processability and surface aesthetics can be obtained in a composition comprising a hydrogenated block copolymer, wherein the hydrogenated block copolymer comprises a hard segment phase volume of at least two distinct blocks of hydrogenated polymerized vinyl aromatic monomer, herein referred to as hydrogenated vinyl aromatic polymer block, and a soft segment phase volume of at least one block of hydrogenated polymerized conjugated diene monomer, herein referred to as hydrogenated conjugated diene polymer block, wherein the hydrogenated block copolymer is further characterized by:
a) a sufficient soft segment phase volume such that a lamellar morphology is achieved,
b) a total number average molecular weight (Mnt) of from 35,000 to 65,000; and
c) a hydrogenation level such that each hydrogenated vinyl aromatic polymer block has an aromatic hydrogenation level of greater than 90 percent and each hydrogenated conjugated diene polymer block has a hydrogenation level of greater than 95 percent.
It has been surprisingly discovered that this composition offers excellent impact, processability and surface aesthetic properties and is ideal for use in extruded sheet applications.
The composition of the present invention comprises a hydrogenated block copolymer of alternating blocks having at least three blocks as represented by the formula A(BA)n, wherein A is a hydrogenated vinyl aromatic polymer hard block and B is a hydrogenated conjugated diene polymer soft block, wherein n is an integer from 1-3, including triblock, multi-block, tapered block, and star block copolymers, e.g. as SB""S, SB""SB""S, and the like (wherein S is hydrogenated polystyrene, Bxe2x80x2 is hydrogenated polybutadiene). The block copolymers may, however, contain any number of additional blocks, wherein these blocks may be attached at any point to the block copolymer backbone, as long as a lamellar morphology is still achieved. Thus, linear blocks would include for example ABA, ABAB, ABABA, ABABAB, and the like. The block copolymer can also be branched, wherein polymer chains are attached at any point along the block copolymer backbone. In addition, blends of any of the aforementioned block copolymers can also be used as well as blends of the block copolymers with their homopolymer counterparts as long as the required properties of the composition are met. In other words, an ABA block copolymer can be blended with a ABABA block copolymer and/or an A homopolymer, as long as lamellar morphology is still achieved.
The vinyl aromatic monomer used in preparing block copolymers, which are subsequently hydrogenated, is typically a monomer of the formula:
wherein Rxe2x80x2 is hydrogen or alkyl, Ar is phenyl, halophenyl, alkylphenyl, alkylhalophenyl, naphthyl, pyridinyl, or anthracenyl, wherein any alkyl group contains 1 to 6 carbon atoms which may be mono or multisubstituted with functional groups such as halo, nitro, amino, hydroxy, cyano, carbonyl and carboxyl. More preferably Ar is phenyl or alkyl phenyl with phenyl being most preferred. Typical vinyl aromatic monomers include styrene, alpha-methylstyrene, all isomers of vinyl toluene, especially paravinyltoluene, all isomers of ethyl styrene, propyl styrene, butyl styrene, vinyl biphenyl, vinyl naphthalene, vinyl anthracene and the like, and mixtures thereof. The block copolymer can contain more than one specific polymerized vinyl aromatic monomer. In other words, the block copolymer can contain a polystyrene block and a poly-alpha-methylstyrene block. The hydrogenated vinyl aromatic polymer block may also be a hydrogenated copolymer of a hydrogenated vinyl aromatic, wherein the vinyl aromatic portion is at least 50 weight percent of the copolymer, as long as lamellar morphology is still achieved.
The conjugated diene monomer used in preparing block copolymers, which are subsequently hydrogenated, can be any monomer having two conjugated double bonds. Such monomers include for example 1,3-butadiene, 2-methyl-1,3-butadiene, 2-methyl-1,3 pentadiene, isoprene and similar compounds, and mixtures thereof. In one embodiment, the conjugated diene polymer block is a polybutadiene. Polybutadiene can contain either a 1,2 configuration, which hydrogenates to give the equivalent of a 1-butene repeat unit, or a 1,4-configuration, which hydrogenates to give the equivalent of an ethylene repeat unit.
A block is herein defined as a polymeric segment of a copolymer which exhibits microphase separation from a structurally or compositionally different polymeric segment of the copolymer. Microphase separation occurs due to the incompatibility of the polymeric segments within the block copolymer. The separation of block segments can be detected by the presence of distinct glass transition temperatures. Microphase separation and block copolymers are widely discussed in xe2x80x9cBlock Copolymers-Designer Soft Materialsxe2x80x9d, PHYSICS TODAY, February, 1999, pages 32-38.
Block copolymers useful in the composition of the present invention, advantageously have a specific morphology. Morphology is the mesoscopic self assembly of the blocks in the molten and solid states producing compositional patterns as described in xe2x80x9cBlock Copolymers-Designer Soft Materialsxe2x80x9d PHYSICS TODAY, February 1999 by Bates and Fredrickson. The specific advantageous morphology for use in the composition of the present invention is a lamellar morphology, wherein the self assembly of blocks is in discrete layers. Morphology can be determined by SAXS (small angle x-ray scattering) analysis, which is well known by those skilled in the art and described in The Physics of Block Copolymers, Ian W. Hamley, Chapter 5, Oxford University press, 1998, NY.
Lamellar morphology can be achieved in different ways and is dependent upon the phase volume of the soft block segment. Generally, the soft segment phase volume is of a sufficient quantity to achieve a lamellar morphology. Typically the phase volume of the soft block segment will be greater than 35, preferably greater than 37, more preferably greater than 40 and most preferably greater than 45 to 65, preferably to 60, more preferably to 55 and most preferably to 45 weight percent conjugated diene, based on the total weight of the block copolymer. The weight ratio of hydrogenated conjugated diene polymer block to hydrogenated vinyl aromatic polymer block is typically 35:65 or more, preferably greater than 40:60. The total weights of the hydrogenated vinyl aromatic polymer blocks and the hydrogenated conjugated diene polymer block(s) is typically at least 80 weight percent, preferably at least 90, and more preferably at least 95 weight percent of the total weight of the hydrogenated copolymer.
The total number average molecular weight (Mnt) of the hydrogenated block copolymers useful in the present invention is typically from 35,000, preferably from 42,000, more preferably from 45,000 and most preferably from 47,000 to 80,000, typically to 70,000, and generally to 60,000. The Mn, as referred to throughout the present specification, is determined by gel permeation chromatography, compared against polystyrene standards. The molecular weight of the hydrogenated block copolymer and properties obtained are dependent upon the molecular weight of each of the hydrogenated polymeric blocks.
The Mna of the hydrogenated vinyl aromatic polymer block will typically be from 6,000, preferably from 7,000, more preferably from 8,000 to 50,000, preferably to 40,000, more preferably to 30,000 and most preferably to 25,000. The hydrogenated conjugated diene polymer block will typically have a Mnb of from 3,000, preferably from 5,000 to 30,000, preferably to 25,000, and most preferably to 20,000.
Each individual block of the hydrogenated block copolymer can have its own distinct Mn. In other words, for example, two hydrogenated vinyl aromatic polymer blocks within the hydrogenated block copolymer may each have a different Mn.
The order-disorder temperature (ODT) of the hydrogenated block copolymer of the present invention must be below the degradation temperature of the hydrogenated block copolymer and is also determined by the Mn. This allows for ease in processing at typical extruder temperatures. Typically, the ODT is from 150xc2x0 C. to 350xc2x0 C., but is generally less than or equal to 350xc2x0 C., preferably less than 325, more preferably less than 300, and most preferably less than 290xc2x0 C.
Methods of making block copolymers are well known in the art. Typically, block copolymers are made by anionic polymerization, examples of which are cited in Anionic Polymerization: Principles and Practical Applications, H. L. Hsieh and R. P. Quirk, Marcel Dekker, N.Y., 1996. In one embodiment, block copolymers are made by sequential monomer addition to a carbanionic initiator such as sec-butyl lithium or n-butyl lithium. In another embodiment, the copolymer is made by coupling a triblock material with a divalent coupling agent such as 1,2-dibromoethane, dichlorodimethylsilane, or phenylbenzoate. In this embodiment, a small chain (less than 10 monomer repeat units) of a conjugated diene polymer can be reacted with the vinyl aromatic polymer coupling end to facilitate the coupling reaction. Vinyl aromatic polymer blocks are typically difficult to couple, therefore, this technique is commonly used to achieve coupling of the vinyl aromatic polymer ends. The small chain of diene polymer does not constitute a distinct block since no microphase separation is achieved. Coupling reagents and strategies which have been demonstrated for a variety of anionic polymerizations are discussed in Hsieh and Quirk, Chapter 12, pgs. 307-331. In another embodiment, a difunctional anionic initiator is used to initiate the polymerization from the center of the block system, wherein subsequent monomer additions add equally to both ends of the growing polymer chain. An example of a such a difunctional initiator is 1,3-bis(1-phenylethenyl) benzene treated with organolithium compounds, as described in U.S. Pat. Nos. 4,200,718 and 4,196,154, which are herein incorporated by reference.
After preparation of the block copolymer, the copolymer is hydrogenated to remove sites of unsaturation in both the conjugated diene polymer block and the vinyl aromatic polymer block segments of the copolymer. Any method of hydrogenation can be used and such methods typically include the use of metal catalysts supported on an inorganic substrate, such as Pd on BaSO4 (U.S. Pat. No. 5,352,744) and Ni on kieselguhr (U.S. Pat. No. 3,333,024) both of which are incorporated herein by reference. Additionally, soluble, homogeneous catalysts such those prepared from combinations of transition metal salts of 2-ethylhexanoic acid and alkyl lithiums can be used to fully saturate block copolymers, as described in Die Makromolekulare Chemie, Volume 160, pp. 291, 1972. The copolymer hydrogenation can also be achieved using hydrogen and a heterogeneous catalyst such as those described in U.S. Pat. Nos. 5,352,744, 5,612,422 and 5,645,253 which are herein incorporated by reference. The catalysts described therein are heterogeneous catalysts consisting of a metal crystallite supported on a porous silica substrate. An example of a silica supported catalyst which is especially useful in the polymer hydrogenation is a silica which has a surface area of at least 10 m2/g which is synthesized such that is contains pores with diameters ranging between 3000 and 6000 angstroms. This silica is then impregnated with a metal capable of catalyzing hydrogenation of the polymer, such as nickel, cobalt, rhodium, ruthenium, palladium, platinum, other Group VIII metals, combinations or alloys thereof Other heterogeneous catalysts can also be used, having average pore diameters in the range of 500 to 3,000 angstroms.
Alternatively, the hydrogenation can be conducted in the presence of a mixed hydrogenation catalyst characterized in that it comprises a mixture of at least two components. The first component comprises any metal which will increase the rate of hydrogenation and includes nickel, cobalt, rhodium, ruthenium, palladium, platinum, other Group VIII metals, or combinations thereof. Preferably rhodium and/or platinum is used. However, platinum is known to be a poor hydrogenation catalyst for nitrites, therefore, platinum would not be preferred in the hydrogenation of nitrile copolymers. The second component used in the mixed hydrogenation catalyst comprises a promoter which inhibits deactivation of the Group VIII metal(s) upon exposure to polar materials, and is herein referred to as the deactivation resistant component. Such components preferably comprise rhenium, molybdenum, tungsten, tantalum or niobium or mixtures thereof.
The amount of the deactivation resistant component in the mixed catalyst is at least an amount which significantly inhibits the deactivation of the Group VIII metal component when exposed to polar impurities within a polymer composition, herein referred to as a deactivation inhibiting amount. Deactivation of the Group VIII metal is evidenced by a significant decrease in hydrogenation reaction rate. This is exemplified in comparisons of a mixed hydrogenation catalyst and a catalyst containing only a Group VIII metal component under identical conditions in the presence of a polar impurity, wherein the catalyst containing only a Group VIII metal component exhibits a hydrogenation reaction rate which is less than 75 percent of the rate achieved with the mixed hydrogenation catalyst.
Preferably, the amount of deactivation resistant component is such that the ratio of the Group VIII metal component to the deactivation resistant component is from 0.5:1 to 10:1, more preferably from 1:1 to 7:1, and most preferably from 1:1 to 5:1.
The mixed catalyst can consist of the components alone, but preferably the catalyst additionally comprises a support on which the components are deposited. In one embodiment, the metals are deposited on a support such as a silica, alumina or carbon. In a more specific embodiment, a silica support having a narrow pore size distribution and surface area greater than 10 meters squared per gram (m2/g) is used.
The pore size distribution, pore volume, and average pore diameter of the support can be obtained via mercury porosimetry following the proceedings of ASTM D-4284-83.
The pore size distribution is typically measured using mercury porosimetry. However, this method is only sufficient for measuring pores of greater than 60 angstroms. Therefore, an additional method must be used to measure pores less than 60 angstroms. One such method is nitrogen desorption according to ASTM D-4641-87 for pore diameters of less than about 600 angstroms. Therefore, narrow pore size distribution is defined as the requirement that at least 98 percent of the pore volume is defined by pores having pore diameters greater than 300 angstroms and that the pore volume measured by nitrogen desorption for pores less than 300 angstroms, be less than 2 percent of the total pore volume measured by mercury porosimetry.
The surface area can be measured according to ASTM D-3663-84. The surface area is typically between 10 and 100 m2/g, preferably between 15 and 90 with most preferably between 50 and 85 m2/g.
The desired average pore diameter of the support for the mixed catalyst is dependent upon the polymer which is to be hydrogenated and its molecular weight (Mn). It is preferable to use supports having higher average pore diameters for the hydrogenation of polymers having higher molecular weights to obtain the desired amount of hydrogenation. For high molecular weight polymers (Mn greater than 200,000 for example), the typical desired surface area can vary from 15 to 25 m2/g and the desired average pore diameter from 3,000 to 4,000 angstroms. For lower molecular weight polymers (Mn less than 100,000 for example), the typical desired surface area can vary from 45 to 85 m2/g and the desired average pore diameter from 300 to 700 angstroms.
Silica supports are preferred and can be made by combining potassium silicate in water with a gelation agent, such as formamide, polymerizing and leaching as exemplified in U.S. Pat. No. 4,112,032. The silica is then hydrothermally calcined as in Iler, R. K., The Chemistry of Silica, John Wiley and Sons, 1979, pp. 539-544, which generally consists of heating the silica while passing a gas saturated with water over the silica for about 2 hours or more at temperatures from about 600xc2x0 C. to about 850xc2x0 C. Hydrothermal calcining results in a narrowing of the pore diameter distribution as well as increasing the average pore diameter. Alternatively, the support can be prepared by processes disclosed in Iler, R. K., The Chemistry of Silica, John Wiley and Sons, 1979, pp. 510-581.
A silica supported catalyst can be made using the process described in U.S. Pat. No. 5,110,779, which is incorporated herein by reference. An appropriate metal, metal component, metal containing compound or mixtures thereof, can be deposited on the support by vapor phase deposition, aqueous or nonaqueous impregnation followed by calcination, sublimation or any other conventional method, such as those exemplified in Studies in Surface Science and Catalysis, xe2x80x9cSuccessful Design of Catalystsxe2x80x9d V. 44, pg. 146-158, 1989 and Applied Heterogeneous Catalysis pgs. 75-123, Institute Francais du Petrole Publications, 1987. In methods of impregnation, the appropriate metal containing compound can be any compound containing a metal, as previously described, which will produce a usable hydrogenation catalyst which is resistant to deactivation. These compounds can be salts, coordination complexes, organometallic compounds or covalent complexes.
Typically, the total metal content of the mixed supported catalyst is from 0.1 to 10 wt. percent based on the total weight of the silica supported catalyst. Preferable amounts are from 2 to 8 wt. percent, more preferably 0.5 to 5 wt. percent based on total catalyst weight.
The amount of mixed supported catalyst used in the hydrogenation process is much smaller than the amount required in conventional unsaturated polymer hydrogenation reactions due to the high reactivity of the hydrogenation catalysts. Generally, amounts of less than 1 gram of supported catalyst per gram of unsaturated polymer are used, with less than 0.1 gram being preferred and less than 0.05 being more preferred. The amount of supported catalyst used is dependent upon the type of process, whether it is continuous, semi-continuous or batch, and the process conditions, such as temperature, pressure and reaction time wherein typical reaction times may vary from about 5 minutes to about 5 hours. Continuous operations can typically contain 1 part by weight supported catalyst to 200,000 or more parts unsaturated polymer, since the supported catalyst is reused many times during the course of continuous operation. Typical batch processes can use 1 part by weight supported catalyst to 5,000 parts unsaturated polymer. Higher temperatures and pressures will also enable using smaller amounts of supported catalyst. Alternatively, continuous processes can also be used using fixed bed catalysts of the above.
The hydrogenating agent can be any hydrogen producing compound which will efficiently hydrogenate the unsaturated polymer. Hydrogenating agents include, but are not limited, to hydrogen gas, hydrazine and sodium borohydride. In a preferred embodiment, the hydrogenating agent is hydrogen gas.
The level of hydrogenation of the block copolymer is generally greater than 95 percent of the conjugated diene polymer block and greater than 90 percent of the vinyl aromatic polymer block segments, typically greater than 99 percent of the conjugated diene polymer block and greater than 95 percent of the vinyl aromatic polymer block segments, preferably greater than 99.5 percent of the conjugated diene polymer block and greater than 97 percent of the vinyl aromatic polymer block segments, more preferably greater than 99.9 percent of the conjugated diene polymer block and 98.5 percent of the vinyl aromatic polymer block segments, even more preferably greater than 99 percent of the vinyl aromatic polymer segments. The term xe2x80x98level of hydrogenationxe2x80x99 refers to the percentage of the original unsaturated bonds which become saturated upon hydrogenation. The level of hydrogenation for the hydrogenated vinyl aromatic polymer block is determined by UV-VIS spectrophotometry, while the level of hydrogenation of the hydrogenated conjugated diene polymer block is determined by proton NMR.

Hydrogenated block copolymer compositions