Classifications

• • 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
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/08—Anti-corrosive paints
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/83—Chemically modified polymers
  • C08G18/837—Chemically modified polymers by silicon containing compounds
• • 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
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions

Definitions

• the present invention relates to an organic based lacquer/ varnish or coating in the form of organic based gel coatings as defined by the preamble of claims 1 and 8.
• the present invention further relates to the manufacture of lacquer/ varnish or coatings as defined by the preamble of claims 9, 10, 11 and 17 respectively.
• the present invention relates to utilization of such organic based lacquer/ varnish or such coating as a protective coating on surfaces of aluminium or steel, particularly of rolled aluminium.
• the present invention relates to a substrate comprising a coating of above mentioned type. (In the following we will generally - of practical reasons - refer to lacquers/ varnishes as lacquers only).
• EP Al 0 555 052 describes a fluid mixture comprising an acryl monomer, silica particles and at least one initiator for ultraviolet curing of said mixture, as well as a component to inhibit decomposition of the mixture caused by the ultraviolet radiation.
• the silica particles of said mixture are typically of a size 15-30 nm.
• the object of said mixture is the manufacture of transparent, organic based coatings that are wear and weather resistant.
• the patent is limited in its scope to one organic system, namely acryl, which in its basis is a mixture of a monomer with silica particles, not an organic resin.
• wear resistant coatings may be formed from a composition consisting of multifunctional organo-metallic components (designated A) that is combined with an organic monomer which includes several functional groups (designated B).
• A multifunctional organo-metallic components
• B organic monomer which includes several functional groups
• From DE 199 24 644 is known a method for the manufacture of a lacquer comprising nano- particles.
• the method comprises in-situ formation of the particles through hydrolysis and condensation of metal oxides, so-called sol-gel synthesis.
• the objective with performing the manufacture in-situ as suggested, is to control the particle size so that agglomeration does not lead to larger particles than desired.
• This publication too concentrates on systems leading to a single, common network of matrix and nano-particles, cfr. e.g. column 2, line 63-66.
• aqueous paintings and lacquers are dispersions of the relevant polymer, which after removal of the solvent (actually dispersion agent) builds a protective layer. This means that the polymer is not present in the form of an actual solution. When the water evaporates and the polymer settles on a surface, the many minor polymer particles "float together" and builds a continuous, protective coating. Even if this takes place in a degree that is good enough for many purposes, aqueous paintings and lacquers still provide a lot weaker protection than organic based lacquers and solvents, where the polymer prior to application is completely dissolved, and during the hardening builds a continuous protective layer with a basis in the single molecules of the polymer.
• the object of the present invention is to modify the wear resistivity of clear lacquer systems without changing other properties like brightness and glossiness.
• the invention more precisely consists of a lacquer or a gel-coat of the kind mentioned initially, which is characterized by the features defined by the characterizing part of claim 1. Further and preferred embodiments of the lacquer or the gel-coat according to the invention, are defined by the claims 2-7.
• the invention further relates to a finished hardened coating as defined by claim 8.
• the invention further concerns alternative embodiments of a method for the manufacture of such a lacquer or such a gel-coat as mentioned initially, which embodiments are characterized by the features defined by the characterizing parts of claims 9, 10, 11 and 17 respectively. Preferred embodiments of the method according to the invention are defined by the claims 12-16.
• the invention still further concerns a utilization of such a lacquer or such a gel-coat as defined by the characterizing part of claim 18.
• Preferred embodiments of the utilization according to the invention are defined by the claims 19-21.
• the invention relates to substrate comprising a coating of the mentioned type.
• the core of the invention may be expressed as providing the kind of lacquer or coating that the invention relates to with inorganic polymer particles of nano size, i.e. with a particle size mainly in the area 1-100 nm.
• Such particles cannot just be “added” in the form of particles as such, their provision need to take place through one or more of the alternative methods by which the particles are formed through chemical reactions taking place in situ or immediately prior to their addition to the base component of the lacquer.
• the three alternative embodiments of the method according to the invention, defined by the claims 9, 10 and 11 respectively, are in the following also designated as model 1, model 2 and model 3 respectively. It is however, also possible to combine the three methods as defined by claim 17.
• particles of the relevant type and size are not present as discrete particles in a lacquer matrix.
• the particles will rather form their own inorganic/ organic network that comes in addition to the organic network of the lacquer.
• These two networks will be present side by side independent of each other, but they may to a larger or lesser degree be attached to each other through cross-linked bondings.
• the degree of network formation is to some extent dependent also by which of the three manufacturing model that is chosen and by the particle size, and cannot be predicted entirely on a theoretical basis.
• the invention is not, however, limited to certain degrees of network formation or to any certain mechanism for the formation of such networks.
• the lacquer/ gel-coat is present in its fresh form, it will comprise varying degrees of the two networks discussed, but the degree of cross-linking in three dimensions will be significantly lower than in the finished, hardened coating.
• a first particle dispersion is prepared by partial hydrolysis of one or more monomer compounds of the kind previously stated.
• a solvent compatible with the solvent of the lacquer to be modified is used for this purpose.
• the mentioned sol is added to the lacquer, and at this stage the sol includes nano-particles of desired size. It is preferred also to modify the surface of the particles through a treatment that may comprise adsorption of polymers, reactions with a silane, a zirconate, a zircoaluminate, an orthotitanate, an aluminate or a combination of such treatments.
• a solution containing monomer compounds of the formula M(OR) n or R'-M(OR) n is used as a starting solution.
• M is a metal ion and R is an organic group chosen among alkyl, alkenyl, aryl or combinations of these with from 1 to 8 carbon atoms.
• R is a simple alkyl with 1-4 carbon atoms.
• the index is an integer from 1 to 6 dependent upon the valency of the metal ion.
• the first step is hydrolysis of the metal alkoxide, where alkoxide ligands are replaced by hydroxyl groups:
• the second step is condensation, where hydroxyl groups either may react with hydroxyl or alkoxy groups from other metal centres, forming M-O-M bonds and either water or alcohol.
• the resulting solution consists of inorganic polymer particles dispersed in a solvent.
• a preferred variant includes the addition of a compound with functional OH-groups, like e.g. butyldiglycol or ethylhexanol during the hydrolysis/ condensation step. This has shown the formation of a stable sol that is compatible with lacquers/ gel-coats.
• a compound with functional OH-groups like e.g. butyldiglycol or ethylhexanol
• BDG butyldiglycol
• ⁇ -APS ⁇ -aminopropyltriethoxysilane
• a BDG- molecule will be able to substitute an ethoxy-group of ⁇ -APS (-ODGB).
• -ODGB is probably significantly more difficult to substitute by -OH compared to the case of -OEt due to possible interactions between the -ODGB substituent and the Si-atom. Such interactions are not significant between OEt and the Si atom.
• an intermolecular variant is also possible.
• the amino group of a silane molecule in the vicinity of another silane molecule catalyses the hydrolysis/ condensation of the latter silane molecule. This way nano-particles compatible with the acrylic lacquer are formed.
• model 2 a controlled amount of inorganic compounds of the mentioned type is added to an existing commercial clear lacquer or an existing commercial gel-coat.
• the condensation reaction provides for the formation of polymer chains (polymerizes) from monomer (single) molecules
• the hydrolysis provides for a polycrystalline precipitation or oxohydroxide precipitation taking place in contact with the components of the lacquer.
• a suitable choice of inorganic compound combined with exchange (replacement) of alkoxide groups with strong ligands will slow down the hydrolysis reactions compared to condensation reactions, which will ensure that said chains do not become too long, but swill stay within a range herein denoted as oligomers.
• model 1 it is preferred additionally to modify the surface of the particles through a treatment that may comprise adsorption of polymer, reaction with a silane, a zirconate, a zircoalummate, an orthotitane, an aluminate, or a combination of such treatments.
• a treatment may comprise adsorption of polymer, reaction with a silane, a zirconate, a zircoalummate, an orthotitane, an aluminate, or a combination of such treatments.
• model 3 a powder of agglomerated particles of the above mentioned type is first established.
• the agglomerates of the powder are so loose that they may be broken down to particles of nano size with a mechanical treatment, a chemical treatment or a combination of such treatments.
• clay based materials represent an alternative that may be used for model 3.
• a controlled amount of inorganic polymer particles is meant an amount that is sufficient to allow the particles to form such a network as described above.
• the amount required will have to be determined in each separate case in dependence of particle size, particle type and type of lacquer.
• the amounts of inorganic particles will stay between an interval of from 0.5 to 50 % by weight calculated on a basis of the laquer in question. At concentrations close to or below the lower of said limits the particles will only to a limited degree be able to form the network necessary to obtain the desired improvement of the lacquer's properties. At concentrations above said upper limit there is a risk that the particles will negatively affect the lacquer's appearance, so that it will no longer appear as glossy, smooth and clear as prior to the particle addition.
• the metal ion M according to the invention is chosen among a series of metals, such as zirconium, aluminium, titanium, silicon, magnesium, chrome, manganese, iron, cobalt and several others.
• metals such as zirconium, aluminium, titanium, silicon, magnesium, chrome, manganese, iron, cobalt and several others.
• the organic part R of the molecule is an alkyl, an alkenyl, an aryl or a combination of these groups, of practical reasons limited in size to groups comprising a maximum of 8 carbon atoms.
• R does not have more than 4 carbon atoms, and more preferred that it is a simple alkyl like methyl, ethyl, propyl or butyl. While the normal thing will be that one of the three distinct methods for modifying a base lacquer/ gel-coat is chosen for a given application, it is also possible to combine two of the methods or all three methods (or elements of these methods) as defined by claim 17.
• coatings with a thickness between 1 and 50 ⁇ m are made, depending on the coating method and the properties of the substrate. Due to the improved properties of the coating made according to the invention, such as high wear resistance, the coating thickness may be lower, e.g. in the range 1 to 10 ⁇ m.
• lacquers are suited for the purpose of the invention, and the type is largely decided by the area of use. To mention the most important ones, acrylic lacquers, epoxy lacquers, polyester lacquers, polyurethane lacquers, polyamide lacquers and polycarbonate lacquers, may all be used as a the basis lacquer according to the invention.
• a gel-coat is used e.g. to manufacture products like car top-boxes, plastic boats, plastic containers/ tanks or body works, which may all include reinforcements in the form of glass fibres or the like.
• the processing steps are thus significantly different from applying a laquer even though the chemical principles of their outer layer are quite similar.
• a product is gel-coated, a model with a shape complementary to the desired product is first formed in a material to which the gel-coat will not adhere with any significant strength.
• the gel-coat is thereafter applied to the model by means of conventional techniques, and thereafter provided with any desired reinforcements, normally followed by another layer of gel-coat.
• the first applied layer of gel-coat constitutes the outer layer of the product, and has in this connection the same function as the lacquer, namely to form an attractive and strong surface, also providing UV- protection so that the material does not decompose under the top layer.
• a commercial clear polyurethane lacquer (DD lacquer from Scanox, Norway) was modified according to model 2, and applied to a parquet (floor).
• the polyurethane lacquer is a two component lacquer where one component is the resin (component A) and the other component is a hardener (component B).
• TMOS tetramathoxy-orthosilane
• the other board was exposed to a burning flame for at least 20 seconds and thereafter observed.
• the part covered with modified lacquer had turned white due to formation of a thin oxide layer that served to inhibit the flames.
• the part covered with the non-modified lacquer was completely black and had started burning immediately after contact with the flames.
• a commercial clear epoxy lacquer VS 150 from Valspar, USA was modified according to model 2 and used for coating of aluminium sheets.
• the eopxy lacquer was a one component lacquer comprising both the resin and a cross-linker. Modification: 20 ml of a mixture of 61 g tetraethoxy-orthosilane (TEOS) from Sigma Aldrich, CH, 200 g butanol and 121 g aluminium sec-butoxide from Sigma Aldrich, CH was added dropwise with about 2 second intervals between each drop to 40 ml of lacquer under vigorous agitation (800 rpm). The entire process lasted about 40 minutes.
• TEOS tetraethoxy-orthosilane
• the wear resistance properties were tested by means of a hardness pen of type Erichsen, Germany.
• the method consists of making a scratch with the hardness pen.
• the force applied being controlled by a spring.
• the hardness value correlated to the force is read from the pen. Parallel readings showed that the force on the sheet covered by the modified lacquer was beyond 1 N, while the force on the sheet covered by the non-modified lacquer was below 0.2 N.
• Example 3 A commercial clear acrylic lacquer (SZ-006 from Rhenania, Germany) was modified according to model 2 and used for coating aluminium sheets.
• the acrylic lacquer was a one-component lacquer containing both resin and cross-linkers.
• the wear resistance properties were tested by means of a Universal Wear Testing Machine from Eyre/ Biceri.
• One of the lacquered sheets was strapped to the apparatus.
• a cotton pole was attached to the movable part and placed on the lacquered sheet with a constant weight of 588 g (3x load) and the apparatus was started.
• the number of turns was automatically counted. After 20 turns the surface of the sheet was metallized and observed.
• the number of die lines on the part coated with non-modified lacquer was comparatively large. On the part coated with modified lacquer the die lines were barely visible.
• the lacquer was optically clear.
• the clearness of a lacquer may be quantified by measuring the brightness (RD/20).
• the brightness of the modified lacquer had a value of 1793, which was in the magnitude of the brightness of the non-modified lacquer (1773).
• the sol particle size was determined by means of the light scattering principle. A commercial instrument, "Zetasizer 3" from Malvern, UK, was used to determine the size distribution. The size distribution was sharp and the average particle size was 5 nm.
• the wear resistance properties were tested by means of a Universal Wear Testing Machine from Eyre/ Biceri, as for example 3.
• the constant weight was 588 g (3x load).
• the number of die lines on the part coated with non-modified lacquer was comparatively large. On the part coated with modified lacquer the die lines were barely visible. On an empiric scale from 1 to 6 where 1 is best (no die lines) and 6 worst (many die lines) the modified lacquer got value 2 and the non-modified lacquer got value 3.
• the lacquer was optically clear.
• the clearness of a lacquer may be quantified by measuring diffuse transmission. This may be performed e.g. by using a clear glass plate as a substrate for the lacquer. First the diffuse transmission is measured on the glass plate alone. Thereafter the lacquer is applied to the glass plate and the diffuse transmission is measured again. The change in diffuse transmission after the application of the lacquer is a good measure of the clearness of the lacquer (provided that the interface between lacquer and the glass plate does not contribute significantly to the light scattering). The measurements was done with an apparatus according to the DIN 5036 standard.
• Diffuse transmission of the clear glass plate was measured to 0.5%.
• the non-modified lacquer was applied to the glass plate (coating layer of 5 ⁇ m).
• the diffuse transmission was thereafter measured to 1.5%.
• Diffuse transmission for the modified lacquer was measured below 6%.
• the commercial lacquer used for example 3 was modified according to model 1 and applied to alumimum sheets. Modification: 4.7 g of tetra isopropyl orthotitane from Sigma Aldrich, CH was added to 15.3 g pentanoic (valeric) acid under agitation. Thereafter 0.45 g of distilled water was added under agitation. After 15 minutes agitation of this sol, 10 g sol was added to 10 g lacquer under agitation.
• the sol particle size was measured by means of "Zetasizer 3" from Malvern, UK. The size distribution was sharp and the average particle size was 3 nm.
• the wear resistance properties were tested by means of a Universal Wear Testing Machine from Eyre/ Biceri, as for example 3.
• the constant weight was 980 g (5x load).
• the number of die lines on the part coated with non-modified lacquer was comparatively large. On the part coated with modified lacquer the die lines were barely visible. On an empiric scale from 1 to 6 where 1 is best (no die lines) and 6 worst (many die lines) the modified lacquer got value 3 and the non-modified lacquer got value 6.
• the lacquer was optically clear.
• the clearness of a lacquer may be quantified by measuring the brightness (RD/20).
• the brightness of the modified lacquer had a value of 1693, which was comparable to the brightness of the non-modified lacquer (1773).
• a commercial clear gel-coat was modified according to model 1 and used for providing a protective layer on a glass reinforced polyester plate.
• a zirconia sol adapted to styrene was manufactured by mixing 40 ml of a Zr(OPr) 4 solution from Sigma Aldrich, CH with 29.6 ml methacrylic acid under agitation. When the composition had reached room temperature 3.72 ml water was slowly added under agitation. Thereafter 40 ml of styrene was added. Unsaturated polyester was added to the composition to yield a 70% polyester. After the addition of peroxide the composition was applied to a mould with a brush and reinforced with polyester/ glass.
• a commercial clear epoxy lacquer was modified according to model 3 and applied to aluminum sheets.
• the epoxy lacquer was a one-component lacquer comprising both the resin and the cross- linker. Modification: 9 g of a commercial bohemite powder from Condea Chemi was added to 20 g butanol under agitation. Thereafter 2.14 g of methacrylic acid was added under agitation. After 15 minutes of agitation the resulting sol was subjected to an ultrasound treatment (300 W 5min., 50% pulse), and the sol was added to 10 g of lacquer under agitation.
• the wear resistance properties were tested by means of a Universal Wear Testing Machine from Eyre/ Biceri, as in example 3.
• the constant weight was 588 g (3x load).
• the number of die lines on the part coated with non-modified lacquer was comparatively large. On the part coated with modified lacquer the die lines were barely visible. On an empiric scale from 1 to 6 where 1 is best (no die lines) and 6 worst (many die lines) the modified lacquer got value 1 and the non-modified lacquer got value 3.
• the lacquer was optically clear.
• the clearness of a lacquer may be quantified by measuring the brightness (RD/20).
• the brightness of the modified lacquer had a value of 1727, which was comparable to the brightness of the non-modified lacquer (1693)
• ⁇ -aminopropyltriethoxysilane 60 g was added to 13.2 g of BDG and 15.18 g of distilled water. The sol was agitated moderately for 12 hours. 5 g of the sol was then added to 1 g of lacquer under moderate agitation.
• the wear resistance properties were measured by means of a "taber abraser" according to ISO standard D 4060-95.
• the method comprises exposing the lacquered surface to wear by means of a rubber wheel rotating on the sample. The number of turns is automatically registered (1000 turns), and the force is determined by a known weight (500 g). The sheets are weighed before and after the test. The weight loss of the sheet coated with non-modified lacquer was 12.37 mg, while the weight loss of the sheet coated with the modified lacquer was 1.22 mg.
• the wear resistance properties were also tested by means of a Universal Wear Testing Machine from Eyre/ Biceri, as in example 3.
• the constant weight was 980 g (5x load).
• the number of die lines on the part coated with non-modified lacquer was comparatively large. On the part coated with modified lacquer the die lines were barely visible. On an empiric scale from 1 to 6 where 1 is best (no die lines) and 6 worst (many die lines) the modified lacquer got value 1 and the non-modified lacquer got value 6.
• the wear resistance properties were tested by means of a Universal Wear Testing Machine from Eyre/ Biceri, as in example 3.
• the constant weight was 588 g (3x load).
• the number of die lines on the part coated with non-modified lacquer was comparatively large. On the part coated with modified lacquer the die lines were barely visible. On an empiric scale from 1 to
• the present invention largely is related to modification of existing, commercial lacquers/ varnishes or gel-coats, but is not exclusively limited to such products.
• the invention is thus applicable to other lacquer/ varnishes, e.g. special lacquers that have not earlier been commercially available and new lacquers or varnishes that may possible constitute separate invention per se., etc.
• lacquers/ varnishes or gel- coats that are ready for use. In a commercial situation it may very well be more convenient to perform the modification by introducing the nano-particles as another step of the process than the very last one.

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• Chemical & Material Sciences (AREA)
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• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
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• General Chemical & Material Sciences (AREA)
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• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
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• Laminated Bodies (AREA)

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Citations (13)

• 2000
  • 2000-07-05 NO NO20003462A patent/NO319405B1/no unknown
• 2001
  • 2001-07-05 CA CA002415045A patent/CA2415045A1/en not_active Abandoned
  • 2001-07-05 JP JP2002514237A patent/JP2004504472A/ja active Pending
  • 2001-07-05 AU AU2001290356A patent/AU2001290356A1/en not_active Abandoned
  • 2001-07-05 EP EP01970355A patent/EP1297080A2/en not_active Withdrawn
  • 2001-07-05 WO PCT/NO2001/000287 patent/WO2002008343A2/en active Application Filing

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