The invention relates to anti-skinning agents containing mixtures of organic compounds (combinations of additives), whereby the organic compounds are selected from the groups of organic hydroxylamines, and xcex2-dicarbonyl compounds and/or selected derivatives of formic acid and also relates to compositions containing them, especially oxidatively drying paints or coating compositions.

The invention relates to anti-skinning agents containing mixtures of organic compounds (combinations of additives) and coating compositions containing them. The organic compounds are selected from the groups of organic hydroxylamines, and xcex2-dicarbonyl compounds and/or selected derivatives of formic acid. The invention further relates to compositions containing these anti-skinning agents, like coating compositions such as oxidatively drying paints.
Colorless and pigmented oxidatively drying paints and coatings based on oxidatively drying oils, alkyd resins, epoxy esters and other oxidatively drying refined oils are known. These oils and binders crosslink oxidatively under the influence of oxygen (preferably atmospheric oxygen) by means of the addition of driers, such as metal carboxylates of transition metals. If this crosslinking takes place before the product is actually used, they can form a solid binder film, a skin, on the surface when stored in open or closed containers. This is highly undesirable and should therefore be avoided since it makes the paint more difficult to work with, and commonly interferes with the uniform distribution of the driers. The accumulation of the driers in the paint skin that forms can lead to considerable delays in the drying of the paint when it is applied.
Skinning in the paint film after application is also disadvantageous. Excessively rapid drying of the surface of the paint prevents the lower film layers from drying evenly because they are shielded from oxygen, which is prevented from sufficiently penetrating into and dispersing within the paint film. This can lead among other things to flow problems in the paint film, adhesion problems, or insufficiently hard films.
It is known to add organic substances to the paint that inhibit the reaction of the drier metal with (atmospheric) oxygen by binding the oxygen or by complexing of the drier metal. Formulations of known compounds that are suitable for this purpose can be found e.g. in H. Kittel xe2x80x9cLehrbuch der Lacke und Beschichtungenxe2x80x9d, Colomb Verlag 1976; J. Bieleman xe2x80x9cLackadditivexe2x80x9d Wiley VCH 1998 or Rxc3x6mpp Lexikon xe2x80x9cLacke und Druckfarbenxe2x80x9d, Thieme Verlag 1998.
Furthermore, DE-A 3 418 988 describes the use of aliphatic xcex1-hydroxy ketones as anti-skinning agents, and DE-A 1 519 103 discloses N,N-dialkylated hydroxylamines for this purpose. Because of their low volatility, however, these agents can lead to severe delays in drying and often also to reduced film hardness values, so that their possible applications are limited. They have not been able to gain acceptance as anti-skinning agents.
EP-A 0 903 380 describes the use of xcex1-keto-functionalised carboxylic acids and dicarboxylic acids and of derivatives thereof, optionally in combination with diketo compounds, as anti-skinning agents. A disadvantageous property of such products lies in their limited stability and hence restricted storage life.
Finally, pyrazole or imidazole derivatives, optionally in combination with aliphatic diketones, in particular acetylacetone, are recommended for this purpose in WO 00/11090. However, the cited aromatic amines can cause severe discoloration in the coating composition and also in the applied paint film and likewise give rise to severe delays in drying.
Oximes (in particular butanone oxime) or suitable phenolic compounds are mostly used today as anti-skinning agents in industry. The phenolic anti-skinning agents display a significant delay in surface drying, however, such that alone they are only suitable for certain coating compositions. Oximes such as e.g. methyl ethyl ketoxime or butyraldoxime, on the other hand, display only slight delays in surface drying due to their volatility. The most significant disadvantage of the oximes, which are widely used today, lies in their toxicity. In long-term inhalation studies on rats and mice, for example, an increased occurrence of liver tumors was observed after exposure to butanone oxime, as a result of which the German MAK committee has classified the substance as a category III A 2 carcinogen (MAK list 1997) [MAK=maximum allowable concentration in the workplace]. As a consequence of this, users have to observe elaborate personal protection precautions when working with paints containing oximes as anti-skinning agents.
It is an object of the present invention to develop organic compounds which prevent skinning in paints and coating compositions over an extended period and display only a slight delay in surface drying. Furthermore, the film hardness values obtained in the resulting films or coatings should not be negatively influenced and no discoloration should be caused. The products should display no disadvantageous toxicological properties.
It is another object of the invention that the organic compounds can be incorporated into many different oxidatively drying paints and coatings and by virtue of their physical properties can be used straight-forwardly and for many purposes in corresponding coating compositions.
Surprisingly it was found that these requirements could be achieved by the use of mixtures containing the organic compounds described below. In particular, the above-mentioned disadvantages of the specified hydroxylamines as anti-skinning agents could also be avoided by combining such substances with the additional compounds described below, and hence products that better satisfy requirements as anti-skinning agents are obtained.
In air-drying paints the mixtures according to the invention are suitable for preventing undesirable skinning, for improving the complete drying of paint films after application and for reducing the tendency of the applied paint film to discolor.
The invention relates to an anti-skinning agent containing
a) an organic compound of formula (I)
where
R1 and R2 mutually independently represent hydrogen, a linear or branched, saturated or unsaturated C1-C20 aliphatic radical, which can optionally be mono- or polysubstituted, or a C6-C12 aryl radical, a C7-C14 araliphatic radical or a C5-C7 cycloaliphatic radical,
and either or both of
b) an organic compound of formula (II)
where
R3 represents hydrogen, a hydroxyl radical, a substituted or unsubstituted, saturated or unsaturated C1-C19 aliphatic radical, a C1-C7 alkoxy radical, or an amine radical xe2x80x94NR7R8,
R4 represents hydrogen, hydroxyl radical, a substituted or unsubstituted, saturated or unsaturated C1-C19 aliphatic radical, a C1-C7 alkoxy radical, or an amine radical xe2x80x94NR9R10,
R7 and R8 mutually independently represent hydrogen or a C1-C6 aliphatic radical,
R9 and R10 mutually independently hydrogen or a C1-C6 aliphatic radical, and
c) an organic compound of formula (III)
where
R5 represents hydrogen, a hydroxyl radical or a C1-C7 alkoxy radical and
R6 represents hydrogen or an amine radical xe2x80x94NR11R12,
R11 and R12 mutually independently represent hydrogen, substituted or unsubstituted C1-C6 aliphatic radical, or substituted or unsubstituted C5-C7 cycloaliphatic radical, or amine radical xe2x80x94NR1R2
with the proviso that R5 and R6 are not simultaneously hydrogen.
The invention also relates to compositions of matter containing these anti-skinning agents.
For the purposes of the invention mixtures of organic compounds of formulae (I) to (III) are used alone or as solutions or dispersions or emulsions in water and/or organic solvents. Suitable organic solvents include all conventional solvents, such as aromatics, white spirits, ketones, alcohols, ethers and fatty acid esters.
For the use according to the invention the organic compounds of formulae (I) to (III) can be used in a broad range of mixtures with one another. They are preferably used in the ratio (I):(II) or (III)=0.1:10 to 10:0.1 parts. In a mixture consisting of all three components, each of the components can mutually independently preferably be used in the ratio 0.1 to 10 to each of the other components used. They can be used in pure form or in aqueous solution or aqueous dispersion or emulsion or in the form of solutions in organic solvents, whereby aqueous in this context is intended to mean that water is either the sole solvent or is added in a quantity of over 50 wt. % relative to the solvent blend together with conventional organic solvents (e.g. alcohols).
The amount of anti-skinning agents primarily depends on the content of binder and drier used in the particular coating composition. As a general rule between 0.001 and 2.0 wt. % of mixtures of compounds according to formulae (I) to (III) should be added. Preferred amounts to be used are 0.01 to 0.5 wt. %, relative in each case to the overall recipe of the coating composition. The amounts can also depend on the type of binder and the pigments used. Thus in special systems the relative amount of additive to be used can also be greater than 2.0 wt. % (relative to the overall recipe).
It is an advantage of the anti-skinning agent of the present invention that it reliably prevent skinning in a wide range of binders and when used with various driers but does not unfavorably influence other drying properties of the paint.
The invention is further illustrated but is not intended to be limited by the following examples in which all parts and percentages are by weight unless otherwise specified.

Anti-skinning agents having a mixture of organic compounds and coating compositions containing them


An assay method for detecting potential cardiovascular disease (CVD) in a vascularized subject by assessing the concentration of holo-transcobalamin II (holo-TCII) in a sample from the subject where abnormally low levels of holo-TCII are indicative of CVD or susceptibility to CVD.

The present invention relates to an assay method for detecting potential cardiovascular disease (CVD) in a vascularized subject, e.g. a human or non-human animal, especially a mammal, and in particular to an assay method which may be used to detect potential cardiovascular disease before the onset of CVD symptoms noticeable by the subject.
Cardiovascular disease is a major source of ill health among the human, population yet early or preemptive treatment, e.g. with change of diet, reduction or cessation of smoking, increase in regular exercise, prescription of lipid lowering drugs, etc., has a high success rate.
There is accordingly a need for methods which can be used to detect CVD or the potential for or propensity to CVD before the disease has progressed beyond the stage where treatment is routinely successful or may be used to prevent further progression of the disease, and in particular to detect CVD at the early stages when the symptoms are, not apparent to the patient or his physician.
Such methods may be used to screen the general population, or at-risk groups within the population, e.g. males over 40, workers in high stress jobs, patients with unhealthy diets, smokers, etc. where potential CVD or propensity to CVD is diagnosed, preemptive treatment may be given and/or the patient may be encouraged to make adjustments to lifestyle and habits. Likewise, where CVD, potential CVD or propensity to CVD is detected, the patient may be submitted to further testing, e.g. using more expensive or time consuming techniques, such as ECG, with and. without physical activity, radioisotope imaging of myocardial perfusion, X-ray (e.g. CT) myocardial angiography, MR myocardial angiography or perfusion imaging, etc. to confirm the presence and status of CVD. By the use of such assay methods as a xe2x80x9ccoarse filterxe2x80x9d screening technique, unnecessary use of such expensive and time-consuming tests may be avoided while still increasing the. likelihood of as-yet undiscovered CVD being found and treated before health damage becomes irreversible.
The present invention is based on the realization that the protein complex holo-transcobalamin II, (holo TCII) a complex of the carrier protein transcobalamin II (TCII) and Vitamin B12 (cobalamin) is at efficient marker for cardiovascular disease, and in particular that abnormal low holo-TCII levels in body fluids such as blood is indicative of CVD or susceptibility to CVD.
For the avoidance of doubt, the term xe2x80x9ccobalaminxe2x80x9d is used herein synonymously with xe2x80x9cvitamin B12xe2x80x9d and includes all forms of vitamin B12 (e.g. cyanocobalamin; 5-6-dimethyl-benzimidazolyl cyanocobamide; methylcobalamine; 5xe2x80x2-deoxyadenoaylcobalamin) as may occur and be metabolically active (when appropriately presented) in the body.
Vitamin B12 (cobalamin) is a water soluble vitamin which forms part of the vitamin B complex found in foods. The core molecule consists of a corrin ring of four pyrole units which surround the essential cobalt atom. Cobalamin is the only vitamin which cannot be synthesised by animals or plants and must be absorbed from food in the gut. It can however be stored in the liver. It is synthesised by micro-organisms, in particular by anaerobic bacteria and yeasts.
Cobalamin functions in vivo as a co-enzyme and cobalamin enzymes catalyse three types of reaction: (i) intra-molecular rearrangements; (ii) methylations; and (iii) reduction of ribonucleotides to deoxyribonucleotides in some micro-organisms. In mammals, only two enzymic reactions, namely (i) and (ii) above, are known to require cobalamin as a co-enzyme.
In the process of digestion, a salivary protein called haptocorrin (which is also referred to in the art as R-binder or transcobalamins I and III collectively) binds cobalamin in the upper gastrointestinal tract forming a complex which passes through the stomach. Pancreatic enzymes digest the cobalamin-haptocorrin complex in the ileum, liberating cobalamin which is then bound to a protein called intrinsic factor, which is secreted by the gastric mucosa, to form a further complex. The cobalamin-intrinsic factor complex binds to a specific receptor in the lining of the terminal ileum, whereupon it is dissociated by a releasing factor and the cobalamin is transported actively across the membrane of the ileum into the blood stream.
Cobalamin does not circulate in the body in a free form in any appreciable amount. Probably 99% or so of cobalamin is bound by one of the transcobalamin proteins (TC I, II and III) or albumin.
The protein believed to be solely responsible for transporting cobalamin to target tissues is transcobalamin II (TCII), a critical trace protein without which cobalamin cannot cross cell membranes. Despite this important metabolic function, only about 6-25% of cobalamin in the serum is bound to TCIIxe2x80x94most is carried by haptocorrin. TCII comprises a single chain polypeptide of about 40 kDa found primarily in serum, seminal fluid and cerebro-spinal fluid. Cobalamin bound TCII (i.e. holo-TCII) attaches to specific receptors on cell membranes and, once bound, the holo-TCII is taken into cells by pinocytosis. The holo-TCII constitutes the metabolically active pool of cobalamin, since none of the other cobalamin binding proteins, including transcobalamins I and III, are able to facilitate entry of the vitamin into cells.
TCII is synthesised by the liver, vascular endothelium, enterocytes, macrophages and fibroblasts and circulates predominantly as apo-TCII, i.e. lacking bound cobalamin. It has a short half life of approximately 90 minutes.
Less than about a quarter of the total plasma cobalamin is associated with TCII. The rest is bound to the other transcobalamins or albumin as mentioned above. The function or role of the non-TCII transcobalamins is unclear, but since they bind both cobalamin and cobalamin-like substances, they may play a role in ensuring that potentially harmful analogues of cobalamin cannot compete with cobalamin by virtue of them being unable to enter cells if bound to TC I or III. They may play a role in removing cobalamin analogues from the circulation or may serve as a store of cobalamins. Alternatively, they may ensure that free cobalamin and analogues thereof are not available for utilisation by micro-organisms.
Thus viewed from one aspect the invention provides an assay method for the detection of cardiovascular disease (CVD), potential cardiovascular disease, or propensity to cardiovascular disease in a human or non-human animal subject, said method comprising assessing the concentration of holo-transcobolamin II (holo TCII) in a cobalamin containing sample from said subject, e.g. a sample of blood, plasma, serum, seminal fluid, amniotic fluid or cerebrospinal fluid, preferably a sample of blood, plasma or serum, in particular a sample of serum.
By assessing it is meant that a quantitative or semi-quantitative value for the concentration of holo-TCII is determined. This may be a value for the concentration of the sample as tested, e.g. after treatment to remove cells or other sample components not being assayed for, or to concentrate or dilute the sample or to transfer the holo-TCII to a separate medium, e.g. a solid substrate.
Alternatively, the assessment may simply be qualitative, ie. to indicate whether the holo-TCII concentration is above or below one or more pre-selected threshold values, e.g. values indicative of absence of CVD detectable by the assay, presence of CVD (or potential CVD or propensity to CVD) as detectable by the assay, or uncertainty as to presence or absence of CVD, etc. The precise values for such threshold values or other reference values for holo-TCII concentration may depend on the nature of the sample, the age, weight, sex and species of the subject and may be determined in a routine manner by testing equivalent subjects without CVD or with CVD at various stages of development.
A value indicative of holo-TCII concentration determined (or xe2x80x9cassessedxe2x80x9d) in accordance with the method of the invention may be an absolute concentration of holo-TCII or may alternatively be an index, ratio, percentage or similar indication of the concentration of holo-TCII and that of some other analyte, e.g. another transcobolamin or homocysteine. A preferred ratio is that between the concentration of holo-TCII and the total cobolamin concentration. Total cobolamin assays are known from the literature as are assays for other analytes such as homocysteine which was mentioned above.
The body sample used in the assay method of the invention may be any cobalamin containing sample, e.g. a body fluid or tissue sample, or a suspension etc. Generally the sample will not be urine or a sample taken from the gastrointestinal tract. Preferably, the sample will be a body fluid for example, seminal fluid, cerebro-spinal fluid or amniotic fluid, or more particularly blood or a blood derived sample. When this is the case, the sample used for analysis will preferably be cell-free and hence either serum or plasma may be used. The sample may be treated prior to being used in the assay method of the invention, for example it may be diluted by adding a buffer or other aqueous medium.
While assays for holo-TCII are known and may be used in the method of the invention, there has not previously been any suggestion that holo-TCII is a marker for CVD or propensity to CVD.
Examples of holo-TCII assays are described or referenced for example in: Herzlich et al., Lab. Invest. 58: 332-337 (1988); Markle, Critical Reviews in Clinical Laboratory Sciences 33: 247-356 (1996); Herbert, Am. J. Clin. Nutrition 59 (5 Suppl.): 1213S-1222S (1994); Das et al., J. Nutr. Biochem. 2: 455-464 (1991); van Kapel et al., Clin. Chim. Acta 172: 297-310 (1988); Lindemans et al., Clin. Chim. Acta 132: 53-61 (1983); Nexxc3x8 et al., Scand. J. Lab. Invest 37: 723-728 (1997); Morelli et al., J. Lab. Clin. Med. 89: 645-652 (1977); Carmel, Am. J. Clin. Pathol. 62: 367-372 (1974); Wickramasinghe et al., J. Clin. Pathol. 46: 537-539 (1993); Vu et al., Am. J. Hematol. 42: 202-211 (1993); Benhayoun et al., Acta Haematol. 89: 195-199 (1993); Rothenberg et al., Methods in Enzymology 281: 261-268 (1997); and in Frater-Schrader et al., pages 877-880 in xe2x80x9cVitamin B12xe2x80x9d, Zagalak et al (Ed), W. De Gruyter, Berlin, 1979.
Thus for example van Kapel et al. (supra) disclose a method for specifically separating TCII from other transcobalamins using heparin sepharose, thus facilitating the quantitation of holo-TCII by radioisotope dilution assay and the concentration of non-cobalamin carrying TCII by measuring the unsaturated cobalamin binding capacity of the bound TCII with radioactive cobalamin. Similar methods using microfine silica such as QUSO(trademark) have been used to bind TCII and allow its purification (in either apo or holo form) from TC I and III (see Das et al. (supra)). It is thought however that heparin sepharose is a more specific binder of TCII and some researchers have reported that TC I and III bind to silica in appreciable amounts (see Benhayoun et al. Acta Haematol. 89:195-199 (1993)). Toft et al. Scand. J. Clin. Lab. Invest. 54:62 (1994)) have recently proposed a method whereby transcobalamin II is adsorbed to cellulose and the cobalamin associated with the bound TCII may be quantified by standard methods.
An immunoassay for holo-TCII in which sepharose anti-TCII is used as described in Lindemans (supra) which uses a technique described by Lindemans et al. in Clin. Chim. Acta 95: 29-33 (1979).
The method currently used in clinical practice for determining holo-TCII involves adsorbing TCII to silica and then assaying the bound fraction for cobalamin content using either an immunoassay (as described for example by Kuemmerle et al. Clin. Chem. 38/10: 2073-2077 (1992) or a microbiological assay, the latter apparently producing the best results. This method is accurate and reliable.
In general, besides the sample under evaluation, calibration samples with known holo-TCII content will also be assessed in the performance of the assay method. Such determinations can be used to plot a calibration curve from which the holo-TCII content of the sample under investigation may be determined. The nature of the calibration samples and selection of conversion or adjustment factors used in the determination of the holo-TCII may vary depending, for example, on the manner in which holo-TCII is detected in the assay technique actually used and on other aspects of the method which affect the assay result, for example, buffer composition, assay conditions etc. Typically, calibration samples having holo-TCII contents of 0 to 300 pmol/L will be used. The reference range within which the value for holo-TCII will generally be found is 0 to 160 pmol/L. A holo-TCII concentration in serum below 35 pmol/L will generally be strongly indicative of deficiency.
A set of cobalamin standards, preferably with an extended concentration range of 80 to 800 pmol/L or broader, e.g. 0 to 1500 pmol/L, may be used to determine the total cobalamin content of the sample, and not just the holo-TCII content, if such a measurement is required.
Besides obtaining a determination of holo-TCII content for the sample under investigation, it may frequently be desirable to determine the total cobolamin content in the sample and/or the apo-TCII content in the sample. Many of the publications referred to above describe how this may be done.
In general, serum total cobolamin content for humans will be in the range 200-600 pmol/L and holo, TCII content will normally represent some 6 to 20% of this, ie. 30-160 pmol/L. A threshold value below which the assay may be held to be predictive of CVD or CVD propensity may generally be about 35 pmol/L, more preferably about 30 pmol/L especially about 20 pmol/L.
However, the threshold values are better calculated from holo-TCII determinations using the same assay technique for the same body sample type from a range of patients of similar type (age, sex, weight, species, etc.) from healthy through early stage CVD to serious CVD. Even more preferably, the threshold values will be values determined for the same patient at an earlier, healthy stage.
Viewed from a further aspect, the present invention provides an assay kit for use in the method of the invention, said kit comprising reagents and instructions for the performance of the assay method and for the interpretation of the results and, optionally, holo-TCII containing reference samples, and optionally, a detector.
The instructions in the kit may for example be in the form of a label, a manual or an instruction leaflet; however they may instead take the form of a computer program or a data carrier, e.g. a computer disc.
The detector, where present, will generally be one capable of detecting a reporter species, e.g. a spectrometer, a nuclear radiation detector, a scattered light detector, etc.
The reagents will be reagents suitable for holo-TCII determination, e.g. reagents as specifie d in t he literature cited herein which relates to holo-TCII determination.


A support assembly provides for a method of mobilization that does not require removal of shelving and restocking of items on gondolas and warehouse pallet racking, even if the gondola or pallet racking is too wide for prior art mobilization methods. The support assembly comprises a pair of tubular members capable of engaging fork-like extensions of a hand truck or the like. The hand truck may have caster wheels for mobilization and may have a lifting mechanism for raising and lowering the support assembly by the fork-like extensions, when tongues extending from the tubular members are aligned and matingly engaged at a middle support and outer supports of the gondola. By using a plurality of such lift assemblies engaged along the length of the gondola or gondola run, a row of gondolas may be lifted and mobilized without removing shelving and restocking items on the shelves, even if the gondola is wide and the items stocked on the shelves of the gondola add substantial weight to the gondola. A push pull rod may be engaged at a engaging loop attached on a lower portion of each of the lift assemblies or a plurality of push pull rods may be engaged at a plurality of the engaging loops, transferring user force on the push pull rods to the lift assemblies as low on the lift assemblies as possible.

Within the context of this specification, gondola, gondola run, gondolas and gondola islands all refer to store shelving known in the field. Gondolas, such as the one depicted in FIGS. 13A-13C, are known with or without a central support column and with one or two sides having shelving attached. Warehouse pallet racking is also known, such as pallet racking used in home centers and warehouses. Unless otherwise expressly indicated, the term gondolas refers to both a single gondola or a gondola run having a plurality of gondolas or both.
Lifting systems are known that use a plurality of caster wheels to mobilize empty gondolas or gondolas that have at least a portion of the racked products removed from the gondolas. U.S. Patent Publication 2007/0194546, published Aug. 23, 2007, and U.S. Patent Publication 2007/0059138, published Mar. 15, 2007 illustrate systems with a screw or hydraulic jack for lifting gondolas, the description and drawings of which are hereby incorporated for background herein. Two devices are disposed on opposite sides of the gondolas at each upright support, which may be accessible behind a kick plate. Each upright support is raised using the lifting apparatus and the gondola, even if quite long, is movable using the lifting system as a hand truck, with each of the hand trucks being moved at the same time.
However, deep gondolas and gondolas with products racked on the gondolas cannot be moved using these known devices. An upright support in the middle of a gondola, between two opposite sides of the gondola, bows excessively, causing damage to the gondola support structure and tumbling of the products. Thus, a time consuming unracking and reracking of at least a significant portion of the products on the gondolas is required in order to mobilize the gondolas.

System for mobilization of stocked gondolas


Wood preservatives contain a copper compound, an alkanolamine, a triazole, an emulsifier and/or a phosphonium compound and are used for impregnating wood.

Wood preservatives based on inorganic copper compounds with alkanolamines as complexing agents are known (European Patent 89,958). Despite high copper contents, the activity of these agents against wood-destroying Basidiomycetes is insufficient in comparison with known copper- and chromate-containing salts having a comparable copper content.
It has now been found that wood preservatives based on copper compounds and alkanolamines, which contain a triazole compound and an emulsifier or which contain a phosphonium compound, have very good activity against wood-destroying Basidiomycetes. The present invention relates to mixtures which contain a triazole compound and an emulsifier, to mixtures which contain a phosphonium compound and to mixtures which contain a triazole compound, an emulsifier and a phosphonium compound.
In spite of the content of copper compounds in the wood preservative, on dilution with water the triazole compounds form a clear emulsion. The advantage of the novel agents is that triazole compounds which are insoluble in water are present in the novel agents in the the form of aqueous emulsions or clear aqueous concentrates. Clear aqueous liquids are formed on dilution with water.
Homogeneous concentrates can be obtained by adding small amounts of organic solvents to the wood preservative, for example alcohols (ethanol or isopropanol), glycols (ethylene glycol or propylene glycol), glycol ethers (ethylene glycol monomethyl ether or ethylene glycol monoethyl ether), glycol ether esters (butylglycol acetate), dimethylformamide or N-methyl-pyrrolidone. The solvents additionally act as solubilizers for the triazoles. With the additional use of arylcarboxylic acids, cycloalkylcarboxylic acids or aliphatic C5-C20-mono- or dicarboxylic acids or corresponding amine, alkali metal or copper salts, however, the use of solvents can be reduced to a minimum for obtaining homogeneous concentrates.
The copper compounds can be used as water-soluble or water-insoluble compounds, for example copper sulfate, copper acetate, copper hydroxide, copper oxide, copper borate, copper fluoride or basic copper carbonate.
An alkanolamine is, in particular, monoethanolamine; the use of other alkanolamines, for example isopropanolamine, 1,1- or 1,2-diaminoethanol, aminoethylethanolamine, diethanolamine, triethanolamine or methylethanolamine, is possible.
The amount of added alkanolamines is advantageously such that a pH of 7 or more, preferably from 8.5 to 10.5, is established in the dilute aqueous impregnating solution. The amount of amines should be sufficient for complexing the copper (1 g atom of copper requires about 4 mol equivalents of amine).
A triazole compound is, for example, 1-(2-(2,4-dichlorophenyl)-4-methyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazole, 1-(2-(2,4-dichlorophenyl)-1,3-dioxolan-2-ylmethyl)-1H-1,2,4-triazole (azaconazole), 1-(2-(2,4-dichlorophenyl)-4-ethyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazole, 1-(2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazole (propiconazole), 1-(2-(2,4-dichlorophenyl)-4-phenyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazole or xcex1-tert-butyl-a-(p-chlorophenylethyl)-H-1,2,4-triazole-1-ethanol (tebuconazole).
An emulsifier is, for example, an anionic, cationic or nonionic emulsifier or a mixture thereof. Nonionic emulsifiers are, for example, adducts of ethylene oxide (EO) or propylene oxide or mixtures thereof with organic hydroxy compounds, for example alkylphenols, fatty acids, fatty alcohols and mixtures thereof. Examples of suitable cationic emulsifiers are quaternary ammonium compounds and/or salts of fatty amines (for example dimethyl-(C12-C14)-alkylamines).
A quaternary ammonium compound is, for example, a compound of the general formula R1R2R3R4N+Zxe2x88x92, where R1 is alkyl of 8 to 20 carbon atoms, in particular alkyl of 12 to 20 carbon atoms or benzyl which is unsubstituted or substituted by C1-C20-alkyl or halogen, R2 is C1-C6-alkyl, C3-C9-alkoxyalkyl or polymeric ethylene oxide (EO) or propylene oxide (PO) where the number of EO or PO units n is from 2 to 50, R3 is C1-C6-alkyl, C3- or C4-alkoxy or polymeric ethylene oxide (EO) or propylene oxide (PO) where the number of EO or PO units n is from 2 to 50 and R4 is C1-C20-alkyl, or two of the radicals R1 to R4, together with the nitrogen atom, form a heterocyclic radical which contains 4 or 5 carbon atoms and one, two or three double bonds, the carbon atoms being unsubstituted or substituted by C1-C4-alkyl or halogen, and Z is an acid radical, eg. halide.
Particularly suitable phosphonium compounds are compounds of the formula
R13R2P+Yxe2x88x92
where R1 is alkyl of 1 to 6 carbon atoms, hydroxyalkyl of 1 to 6 carbon atoms or phenyl, R2 is alkyl of 8 to 18 carbon atoms and Y is an acid radical, in particular a halide anion.
R1 and R2 are preferably straight-chain.
The quaternary phosphonium compounds may be present individually or as mixtures in the novel concentrates. Examples of such phosphonium compounds are trimethyl-n-dodecylphosphonium chloride, triethyl-n-decylphosphonium bromide, tri-n-propyl-n-tetradecylphosphonium chloride, trimethylol-n-hexadecylphosphonium chloride, tri-n-butyl-n-tetradecylphosphonium chloride, tri-n-butyl-n-dodecylphosphonium bromide, tri-n-butyl-n-decylphosphonium chloride, tri-n-butyl-n-hexadecylphosphonium bromide, tri-n-hexyl-n-decylphosphonium chloride, triphenyl-n-dodecylphosphonium chloride, triphenyl-n-tetradecylphosphonium bromide and triphenyl-n-octadecylphosphonium chloride.
Aliphatic carboxylic acids can be added to improve the homogeneity of the concentrates. Examples of such acids are propionic acid, hexanoic acid, heptanoic acid, branched carboxylic acids, eg. 2-ethylenehexanoic acid or isooctanoic acid, neocarboxylic acids, aliphatic dicarboxylic acids, eg. sebacic acid, cycloalkylcarboxylic acids, eg. cyclohexanoic acid, and arylcarboxylic acids, eg. benzoic acid or 3- or 4-hydroxybenzoic acid.
When the abovementioned acids are used, it is advantageous in some cases to improve the penetration of the wood preservative in large scale industrial processes by adding complex-forming, polymeric nitrogen compounds, eg. polyethyleneimines.
Polyethyleneimines (PEI, polymin) are known and are formed by polymerization of 1,2-ethyleneimine. They contain the nitrogen in primary (terminal group), secondary or tertiary (branching) form. Polyethyleneimines where n is greater than 10 are suitable; very good results are obtained when PEI having a degree of polymerization n between 50 and 1,000 are used.
The wood preservatives may, if required, contain further compounds, for example compounds having a fungicidal anion, such as a boron compound (for example alkali metal borate, aminoborate, boric acid or boric ester) and fluorides (for example potassium fluoride and/or salts of fluoboric acid and/or fluophosphoric acid and/or difluophosphoric acid).
The action spectrum of the novel wood preservatives can, if required, be improved by adding further active ingredients. Examples of suitable compounds are N-organodiazeniumdioxy compounds, organotin compounds, in particular tributyltin (TBT) compounds and isothiazoline compounds of the following formula
where R1 is hydrogen, an alkyl, alkenyl or alkynyl radical of 1 to 18 carbon atoms, cycloalkyl having a C3-C6-ring and not more than 12 carbon atoms or an aralkyl or aryl radical of not more than 19 carbon atoms and R2 and R3 independently of one another are hydrogen, halogen or C1-C4-alkyl, or R2 and R3 are part of an aromatic radical.
It is also possible to add further fungicides or insecticides, for example in emulsified form, such as N-tridecyl-2,6-dimethylmorpholine (tridemorph) and/or 4-(3-para-tert-butylphenyl)-2-methyl-propyl-2,6-cis-dimethylmorpholine (fenpropimorph) and/or chlorinated phenols tetrachloroisophthalodinitrile N-cyclohexyl-N-methoxy-2,5-dimethylfuran-3-carboxamide N-dimethyl-Nxe2x80x2-phenyl-(N-fluoromethylthio)-sulfamide N,N-dimethyl-Nxe2x80x2-toluyl-(N-fluoromethylthio)-sulfamide methyl benzimidazole-2-carbamate 2-thiocyanomethylthiobenzothiazole 2-iodobenzanilide 1-(1xe2x80x2, 2xe2x80x2, 4xe2x80x2-triazol-1xe2x80x2-yl)-1-(4xe2x80x2-chlorophenoxy)-3,3-dimethylbutan-2-one 1-(1xe2x80x2, 2xe2x80x2, 4xe2x80x2-triazol-1xe2x80x2-yl)-1-(4xe2x80x2-chlorophenoxy)-3,3-dimethylbutan-2-ol hexachlorocyclohexane O,O-diethyldithiophosphorylmethyl-6-chlorobenzoxazolone 2-(1,3-thiazol-4-yl)-benzimidazole N-trichloromethylthio-3,6,7,8-tetrahydrophthalimide N-(1,1,2,2-tetrachloroethylthio)-3,6,7,8-tetrahydrophthalamide N-trichloromethylthiophthalimide 3-iodo-2-propylbutyl carbamate O,O-dimethyl S-(2-methylamino-2-oxoethyl) dithiophosphate O,O-dimethyl O-(3,5,6-trichloro-2-pyridyl) thiophosphate O,O-dimethyl S-(N-phthalimido)-methyl dithiophosphate O,O-diethyl O-(xcex1-cyanobenzylideneamino) thiophosphate 6,7,8,9,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,3,4-benzodioxothiepene 3-oxide (4-ethoxyphenyl)-(dimethyl)-3-(4-fluoro-3-phenoxyphenyl)-propyl silane 2-sec-butylphenyl N-methylcarbamate 2-propoxyphenyl N-methylcarbamate 1-naphthyl N-methylcarbamate norbornene dimethanohexachlorocyclosulfite 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)-urea synthetic pyrethroids, such as 3-phenoxybenzyl (+)-3-(2,2-dichlorovinyl-2,2-dimethyl)-cyclopropane-1-carboxylate xcex1-cyano-3,3-phenoxybenzyl 3-(2,2-dichlorovinyl-2,2-dimethyl)-cyclopropane-1-carboxylate 3-(2,2-dibromovinyl-2,2-dimethyl)-xcex1-cyano-m-phenoxybenzyl (1R,3R)-cyclopropanecarboxylate (deltamethrin) xcex1-cyano-3-phenoxybenzylisopropyl-2,4-chlorophenyl acetate.
In concentrated form, the water-dilutable wood preservatives generally contain the copper, for example, in an amount of from 1.0 to 15.0% by weight, calculated as metal.
Suitable concentrates consist of, for example,
from 2.50 to 45%, in particular 10 to 20%, of copper compounds,
from 5.00 to 50%, in particular 20 to 40%, of alkanolamine,
from 0.25 to 15%, in particular 1 to 10%, of triazole compounds,
from 2.50 to 40%, in particular 10 to 20%, of phosphonium compounds,
from 0.5 to 30%, in particular 5 to 15%, of an emulsifier,
from 0 to 40% of a compound having a fungicidal inorganic or organic anion,
from 0 to 40% of an organic solvent,
from 0 to 40% of an aliphatic mono- or dicarboxylic acid and/or cycloalkylcarboxylic acid and/or cycloarylcarboxylic acid and
from 0 to 15% of a complex-forming, polymeric nitrogen compound,
the sum being 100% by weight in each case, and, if required, minor amounts of other components, for example ammonia, corrosion inhibitors, complex-forming acids (eg. nitrilotriacetic acid or ethylenediaminetetraacetic acid where water of relatively high hardness is used) and, if required, water, the amount of which however can generally be kept small and which essentially serves handling purposes.
In addition to the wood preservatives (concentrates), the present invention also relates to the impregnating solutions of correspondingly lower individual concentration which can be prepared by diluting the concentrates with water. The application concentration corresponds to, for example, from 0.01 to 1.50% by weight of metal, eg. copper, in the aqueous impregnating solution, depending on the method of impregnation and the level of risk to which the wood to be impregnated is exposed.
Dissolving the copper salts, if necessary with heating, in the alkanolamines, with or without the addition of acid, water or solvents, and subsequent addition of the emulsifier, the triazole compounds and/or phosphonium compounds result in the formation of highly concentrated pastes, liquid concentrates or two-phase mixtures which, after dilution with water, can be used for impregnating wood. They give a clear liquid in water, even at a high concentration.
The impregnating solution can be used for preserving wood by manual methods, such as spraying, brushing on, immersion or trough impregnation, or by large-scale industrial processes, such as the pressure process, alternating pressure process or double vacuum process. Wood is understood both as solid wood and as woodworking materials, such as particle boards or plywood; here, the wood preservative may also be introduced in the glue mixing process.
The degree of fixing of the copper in the novel preservatives is high; it is more than 90% when large scale industrial methods are used.
The concentrates or solutions can be colored by water-soluble or water-emulsifiable dyes and/or pigment preparations.
Wax, paraffin and/or acrylate dispersions may be added to achieve a water-repellant effect or to improve the fixing.
The concentrates can, if required, also be incorporated in binder-containing water-dilutable systems (primers or transparent coats).
The Examples which follow illustrate the invention.
Determination of the limit of action against wood-destroying fungi
The method is used for determining the preventive action of wood preservatives against wood-destroying fungi.
Identical wooden blocks (5xc3x972.5xc3x971.5 cm) dried to a constant weight at 103xc2x0 C. are completely impregnated with stepwise amounts of the wood preservative to be tested and are dried, washed thoroughly with water (washing out the active ingredient mixture from the wood) and exposed to attack by cultures of wood-destroying fungi in glass dishes. The nutrient medium used for the fungi is malt agar (containing 4% of malt extract). The destruction of the wood caused by the fungal attack is measured by the weight loss of the wood specimens; a weight loss of 2% or more is evaluated as wood destruction.
A lower active ingredient concentration at which the wood just begins to be destroyed and an upper active ingredient concentration at which no wood destruction is detectable and hence complete wood preservation has been achieved are stated. It is always necessary to start from the upper active ingredient concentration for evaluating a wood preservative in practice.
The determination of the limit of the action against wood-destroying fungi (in kg of active ingredient or mixture of active ingredients per m3 of wood)
The result should be understood as follows. The lower the limit, the better the fungicidal action. 1 kg/m3 is thus better than 2 kg/m3.


A body of carbonaceous or other material for use in corrosive environments such as oxidising media or gaseous or liquid corrosive agents at elevated temperatures, in particular in molten salts such as cryolite, is coated with a protective surface coating which improves the resistance of the body to oxidation or corrosion and which may also enhance the bodies electrical conductivity and/or its electrochemical activity. The protective coating is applied in one or more layers from a colloidal slurry containing reactant or non-reactant substances, or a mixture of reactant and non-reactant substances, in particular mixtures containing silicon carbide and molybdenum silicide or silicon carbide and silicon nitride, which when the body is heated to a sufficient elevated temperature reaction sinter as a result of micropyretic reaction and/or sinter without reaction to form the protective coating.

The invention relates to bodies of materials such as, for example, carbonaceous materials, for use in corrosive environments such as oxidising media or gaseous or liquid. corrosive agents at elevated temperatures, coated with a protective surface coating which improves the resistance of the bodies to oxidation or corrosion and which may also enhance the electrical conductivity and/or electrochemical activity of the body.
Carbonaceous materials are important engineering materials used in diverse applications such as aircraft bodies, electrodes, heating elements, structural materials, rocket nozzles, metallurgical crucibles, pump shafts, furnace fixtures, sintering trays, induction furnace susceptors, continuous casting dies, ingot molds, extrusion canisters and dies, heat exchangers, anodes, high temperature insulation (porous graphite), gas diffusers, aerospace structural materials, bearings, substrates in electronics industry, brazing and joining fixtures, diamond wheel molds, nozzles, glass molds etc. Although carbonaceous materials have properties which make them useful for the applications mentioned above, the resistance to oxidation is one property which has limited the use of these materials. Much effort is therefore underway to improve the resistance to oxidation of such materials.
Traditional methods of preventing oxidation of carbonaceous materials have involved the deposition of adherent and highly continuous layers of materials such as silicon carbide or metals such as aluminum. The deposit of such materials has normally been carried out by techniques such as vapor deposition (both PVD and CVD) or by electrochemical methods. Vapor deposition is an extremely slow and costly process and additionally may not be carried out for large parts such as electrodes. It is also known to plasma spray alumina/aluminium onto the sides of carbon anodes used as anodes for aluminium electrowinning, but this coating method is expensive. Other techniques such as electrochemical methods are limited in the type of materials that may be applied as coatings and size limitations again may be present. Sol-gel techniques are known for the application of coatings. However, it is well known that these techniques are not adequate for oxidation protection, because they produce extremely thin films, usually of the order of 1 micrometer thick, that are most often porous and have a tendency to delaminate especially under conditions of thermal expansion mismatch with the substrate.
Therefore, there is a need for developing a cost effective versatile method for coating carbonaceous materials with an adherent coating that will effectively prevent oxidation and the loss of the carbonaceous substrate because of rapid or slow burning.
According to the invention, a protective coating on a body of carbonaceous or other material which improves the resistance of the body to oxidation, and which may also enhance the bodies electrical conductivity and/or its electrochemical activity is applied from a colloidal slurry containing particulate reactant or non-reactant substances, or a mixture of particulate reactant and non-reactant substances, which when the body is heated to a sufficient elevated temperature form the protective coating by reaction sintering and/or by sintering without reaction.
The coatings of the invention are xe2x80x9cthickxe2x80x9d coatings, of the order of tens of micrometers thick, and contain refractory particulate materials which adjust to the thermal expansion mismatch and, in most embodiments, after sintering or oxidation during use, are able to provide a continuous thick silica layer for oxidation prevention.
The invention is particularly advantageous when the body is made of carbonaceous material, for instance petroleum coke, metallurgical coke, anthracite, graphite, amorphous carbon, fulerene such as fulerene C60 or C70 or of a related family, low density carbon or mixtures thereof. The coatings are particularly adherent on carbon substrates because the high surface activity bonds the particles to the carbon.
It is advantageous for bodies of low-density carbon to be protected by the coating of the invention, for example if the component is exposed to oxidising gas released in operation of an electrolytic cell, or also when the substrate is part of a cell bottom. Low density carbon embraces various types of relatively inexpensive forms of carbon which are relatively porous and very conductive, but hitherto could not be used successfully in the environment of aluminium production cells on account of the fact that they were subject to excessive corrosion or oxidation. Now it is possible by coating these low density carbons according to the invention, to make use of them in these cells instead of the more expensive high density anthracite and graphite, taking advantage of their excellent conductivity and low cost.
The invention also concerns coated bodies with substrates of a metal, alloy, intermetallic compound or refractory material, to which the protective coating is applied.
Two types of coatings have been developed and are described in this application. One will be called the micropyretic type and the other the non-micropyretic type. Micropyretic coatings contain combustible materials which provide heat during combustion and also add desired constituents to the coating after combustion of the coating. The non-micropyretic type does not contain any combustible. Mixtures of micropyretic and non-micropyretic coatings are also possible. Both coatings involve the application of a colloidal slurry which is applied to the substrate by painting, spraying, dipping or pouring onto the substrate. When several layers of such coatings are applied, it is possible that some may contain micropyretic constituents and some may not.
Thus, the applied colloidal slurry may contain micropyretic particulate reactant substances which undergo a sustained micropyretic reaction to produce for example refractory borides, silicides, nitrides, carbides, phosphides, oxides., aluminides, metal alloys, intermetallics, and mixtures thereof, of titanium, zirconium, hafnium, vanadium, silicon, niobium, tantalum, nickel, molybdenum and iron, the micropyretic reactant substances being finely divided particulates including elements making up the refractory material produced.
Such micropyretic reactant substances may for instance compriseparticles, fibers or foils of Ni, Al, Ti, B, Si, Nb, C, Cr2O3, Zr, Ta, TiO2, B2O3, Fe, Mo or combinations thereof.
It is essential to use colloids and mixtures of colloids for application of the coatings. Three types of colloidal processing are possible. The first involves the gelation of certain polysaccharide solutions. This, however, is relatively unimportant to this invention. The other two which involve colloids and metal organic compounds are relevant to this invention. These two involve the mixing of materials in a very fine scale. Colloids are defined as comprising a dispersed phase with at least one dimension between 0.5 nm (nanometer) and about micrometers in a dispersion medium which in our case is a liquid. The magnitude of this dimension distinguishes colloids from bulk systems in the following way: (a) an extremely large surface area and (b) a significant percentage of molecules reside in the surface of colloidal systems. Up to 40% of molecules may reside on the surface. The colloidal systems which are important to this invention are both the thermodynamically stable lyophylic type (which include macromolecular systems such as polymers) and the kinetically stable lyophobic type (those that contain particles).
Insoluble oxides in aqueous suspension develop surface electric charges by surface hydroxylation followed by dissociation of surface hydroxyl groups. Typical equations could be:
M(OH) surface +H2O⇄MOxe2x88x92surface +H3O+
M(OH) surface +H2O⇄M(OH2)+ surface +OHxe2x88x92
where M represents a metal or a complex cation.
Such surface charges and the London and Van der Waals forces keep the particles from agglomerating. An adsorbed layer of material, polymer or surface active agent, modifies the interaction of particles in several ways. In the mixing process described below we introduce new materials and other agents into the colloids.
Colloids may form through cation hydrolysis. Many metal ions are subject to hydrolysis because of high electronic charge or charge density. Initial products of hydrolysis can condense and polymerize to form polyvalent metal or polynuclear ions, which are themselves colloidal. Charge and pH determine the ligands for central cations and the anion/cation ratio controls the degree of polymerization and stability of the suspension. The pH could vary from 0-14. A wide range of polynuclear cationic hydrolysis products may exist with charge from 2+ to 6+. Polynuclear anionic hydrolysis products could also have a wide range of charges.
The formation of colloids involves a starting material for example a reagent grade metal salt which is converted in a chemical process to a dispersible oxide which forms the colloidal solution on addition of dilute acid or water. Removal of water (drying) and or removal of the anions from the colloidal solution produces a gel like product. In the method of the invention for oxidation resistant coatings, the colloid thus acts as a binder to the other additives and also densifies the product formed. The calcination process in air yields an oxide product after decomposition of salts whereas carbon, silicon, boron etc. may be added to the colloid to yield a non oxide ceramic in the coating. The colloidal solutions may also be blended.
The colloidal carrierxe2x80x94usually colloidal alumina, colloidal ceria, colloidal silica, colloidal yttria or colloidal monoaluminium phosphate and usually in an aqueous mediumxe2x80x94has been found to assist in moderating the micropyretic reaction and to considerably improve the properties of the coating whether produced by reaction sintering or non-reactive sintering. It is however not necessary for all of the applied layers of the slurry to have a colloidal carrier. Excellent results have been obtained using some slurries with a colloidal carrier and others with an organic solvent. Combinations of a colloidal carrier in aqueous medium and an organic solvent have also worked well.
In the case of micropyretic coatings an additional step after the drying of the applied slurry on the coating will be the firing (combustion) of the constituents of the slurry by direct flame, concentrated sunlight, plasma, laser, electron beam or by traditional methods such as passing a current through the conductive substrate or placing the coated article inside a furnace at a predetermined temperature or by heating the coating by an induction method or by radiant heating.
The applied colloidal slurry contains particulate substances which sinter above a given temperature, in particular reactant and/or non-reactant substances like silicon carbide that reaction sinter and/or sinter without reaction above 900xc2x0 C. The coating may be pre-formed prior to use, in which case the reactant and/or non-reactant substances have been reaction sintered and/or sintered without reaction to provide an adherent coating on the body prior to use. Alternatively, the micropyretic reaction sintering or the non-reactive sintering may take place only when the body coated with the coating components is used-at high temperature.
When use of a silicon-carbide-containing coating is contemplated at temperatures below 900xc2x0 C. then normally micropyretic coatings are preferred; when use is contemplated at above 900xc2x0 C. then non-micropyretic coatings are also acceptable. This is because the coatings become effective after they sinter. Above 900xc2x0 C., sintering may occur during exposure to the service conditions at the high temperature. Below 900xc2x0 C. the micropyretic reaction and the combustion initiation process will provide the required heat for the sintering operation. Nevertheless, it remains possible to sinter non-micropyretic coatings above 900xc2x0 C. and then use them below 900xc2x0 C.
In-situ repair of coatings during use is also contemplated by both types of coatings.
The constituents of the slurries are
(a) A carrier, chosen from colloidal liquids which could be colloidal alumina, colloidal ceria, colloidal yttria, colloidal silica, colloidal zirconia or mono-aluminum phosphate or colloidal cerium acetate or mixtures thereof.
(b) A powder additive containing carbides, silicides, borides, nitrides, oxides, nitrides, carbonitrides, oxynitrides, boric acid and its salts, and combinations of these. When choosing combinations of powder additives the particle size selection is of importance. It is preferable to choose particle size below 100 microns and, when employing combinations of powder additives, to choose particle sizes which are varied such that the packing of particles is optimized. For example when choosing a composition containing mostly SiC and some MOSi2 it is preferable to choose the particle size of the MOSi2 much smaller (at least three times smaller) than the SiC. Generally, the ratio of the particle sizes will be in the range from 2:1 to 5:1, preferably about 3:1, for instance with large particles in the range 15 to 30 micrometers and small particles in the range 5 to 10 micrometers.
(c) Metallic particles such as for example Ni, Pt, Al, Cr or intermetallic particles such as for example NiAl, NiAl3, CrSi, CrB etc. or combinations thereof, in which case the particle sizes will be varied to achieve optimum packing, as for powder additives.
(d) Micropyretic agents. These agents are particles, fibers or foils of materials such as Ni, Al, Ti, B, Si, Nb, C, Cr2O3, Zr, Ta, TiO2, B2O3, Fe, Mo or combinations which may react to yield heat as well as yielding clean and nascent products from the combustion. Typical reactions could be for example Cr2O3+2Al+2B which reacts spontaneously to give CrB2 and Al2O3 with a large release of heat. The adiabatic temperature of such a micropyretic reaction is 6500xc2x0 K. Tables I, II and III give a partial listing of examples of micropyretic reactions and products and the amount of heat released in each reaction. xcex94H(KJ/mole) is the enthalpy release for the reaction and Tad K is the adiabatic temperature (xc2x0 K.) which is expected to be reached in such reactions.
(e) Metal organic compounds principally metal alkoxides of the general formula M(OR)z where M is a metal or complex cation made up of two or more elements, R is an alkyl chain and z is a number usually in the range 1 to 12, or alternatively described as solutions in which molecules in which organic groups are bound to a metal atom through oxygen. Examples are silicon tetraisomyloxide, aluminum butoxide, aluminum isopropoxide, tetraethyl orthosilicates, etc. Formates, acetates and acetylacetonates are also considered in this category.
(f) Pyrolizable chlorosilanes, polycarbosilanes, polysilazanes and other organosilicon polymers as binders which pyrolize to useful products for oxidation prevention. Such compounds are expected to participate in the micropyretic reaction in a beneficial but complex manner to increase the yield of useful product with a morphology and size which assists in making the coating more adherent and tight.
(g) Buffer solutions to modify the pH of the slurry. These are standard laboratory grade alkalines or acids.
(h) Binding agents such as methyl cellulose, clays like kaolinite, polyvinyl butyral, fused silica and activators, etc.
Considering the above defined constituent groups (a) to (h), the slurries used in the invention are made up of at least one of the additives from groups (b), (c) and/or (d) in a colloidal carrier from group (a), optionally together with one or more components from groups (e) to (h). Some materials may be present under more than one heading. For instance silica or alumina in colloidal form can be included in the carrier, and in powder form as additive. Particulate nickel and aluminium can be present as a micropyretic reactant, but in excess of the stoichiometric amount, whereby the excess forms a particulate additive. It is also possible for the powder additive to be the same as the reaction product of the micropyretic reaction.
The non-reactant substances may comprise antioxidant or oxidation prevention materials such as boric acid and its salts, and fluorides; bonding enhancing materials such as methyl-cellulose, particulate alumina or urea; metallic, intermetallic, semi-metallic, polymeric, refractory and/or ceramic materials such as borides, carbides, nitrides, silicides, oxides, oxynitrides and mixtures thereof; pyrolizable chlorosilanes, polycarbosilanes, polysilanes and other organometal polymers which pyrolize to useful products for oxidation prevention or enhancing bonding, or their pyrolized products: thermosetting resins; thermoplastic resins; and mixtures thereof.
Examples of thermosetting resins are epoxides, phenolic resins and polyimides. Examples of thermoplastic resins are polycarbonates, eg. Lexan(trademark), polyphenylene sulfides, polyether ether ketones, polysulfones, eg. Udel(trademark), polyetherimides and polyethersulfones.
The coating advantageously contains at least one silicon-containing compound, which may be included as a reactant and/or as a non-reactant, advantageously in a substantial amount, usually accounting for 30 wt % or more of the coating, advantageously 50 wt % or more. Silicon compounds when reacted or sintered form on the body a relatively impervious silica skin, providing excellent resistance against oxidation and corrosion. Formation of such a silicous skin can be enhanced by including colloidal silica in the carrier.
The applied coating for instance contains at least one carbide, nitride, boride or oxide of silicon or combinations thereof, in combination with at least one silicide of titanium, zirconium, hafnium, vanadium, niobium, tantalum, nickel, molybdenum, chromium and iron, or a combination of at least two carbides, nitrides, borides or oxides of silicon. One particularly advantageous combination includes silicon carbide with molybdenum silicide. Another includes silicon carbide with silicon nitride. These silicon-based combinations can be used alone or in combination with other silicon or non-silicon non-reactants or with micropyretic reactants, and particularly with colloidal silica in the carrier. When such coatings are sintered before use in an oxidising atmosphere, or when such coatings are used in an oxidsing atmosphere, the coatings are converted to produce a relatively impervious silica skin.
The invention is useful for protecting the various engineering materials made of carbon listed at the outset. A main application of the invention is however for the protection of components of electrochemical cells for molten salt electrolysis which components in use are exposed to a corrosive atmosphere, or to a molten salt electrolyte, such as cryolite, and/or to a product of electrolyis in the cell. Such components are thus coated with a protective surface coating which improves the resistance of the components to oxidation or corrosion and which may also enhance the electrical conductivity and/or electrochemical activity. The protective coating is applied from a colloidal slurry containing particulate reactant or non-reactant substances, or a mixture of particulate reactant and non-reactant substances, which when the component is heated to a sufficient elevated temperature, prior to or upon insertion in the cell, form the protective coating by reaction sintering and/or by sintering without reaction.
Such components may have a carbonaceous substrate, or a substrate of a metal, alloy, intermetallic compound or refractory material, to which the protective coating is applied. The component may be a cathode or a cathode current feeder, an anode or an anode current feeder, eg. for a Hall-Heroult cell, or a bipolar electrode for new cell designs.
The invention is particularly applicable to components which are exposed to corrosive or oxidising gas released in operation of the cell or present in the cell operating conditions, the component comprising a substrate of carbonaceous material (particularly low-density carbon), refractory material or metal alloy that is subject to attack by the corrosive or oxidising gas and is protected from corrosion or oxidation by the protective surface coating.
The invention also concerns a method of improving the resistance to oxidation or corrosion of a body of material for use in corrosive environments such as oxidising media or gaseous or liquid agents at elevated temperatures, the body being in particular a component of an electrochemical cell for molten salt electrolysis which component in use is exposed to a corrosive atmosphere, or to a molten salt electrolyte and/or to a product of electrolyis in the cell. This method comprises applying to the body a protective coating from a colloidal slurry containing reactant or non-reactant substances, or a mixture of reactant and non-reactant substances, followed by heating the body prior to or during use to a sufficient temperature to cause the reactant and/or non-reactant substances to reaction sinter and/or to sinter without reaction to form an adherent protective coating.
The method of application of the slurry involves painting (by brush or roller), dipping, spraying, or pouring the liquid onto the substrate and allowing for drying before another layer is added. The coating need not entirely dry before the application of the next layer. However if one or more layers with micropyretic constituents are present, then it is preferable to dry completely prior to firing. Layers may be added to already fired coatings either for repair or for additional build up. Even when micropyretic constituents are absent, it is preferred to heat the coating with a suitable heat source such as a torch (butane or oxyacetylene), a laser, a furnace, etc., so as to improve densification of the coating. Heating takes place preferably in air but could be in other oxidising atmospheres or in inert or reducing atmospheres.
The substrate may be treated by sand blasting or pickled with acids or fluxes such as cryolite or other combinations of fluorides and chlorides prior to the application of the coating. Similarly the substrate may be cleaned with an organic solvent such as acetone to remove oily products and other debris prior to the application of the coating. These treatments will enhance the bonding of the coatings to the substrate.
After coating the substrate applied by dipping, painting, spraying or combinations of such techniques in single or multi-layer coatings and drying, a final coat of one or more of the liquids listed in (a)-(e) may be applied lightly prior to use.
More generally, after fabrication and before use, the body can be painted, sprayed, dipped or infiltrated with reagents and precursors, gels and/or colloids.
Examples of some non-micropyretic slurries and some micropyretic slurries are given in Table IV and Table V respectively.

Prevention of oxidation of carbonaceous and other materials at high temperatures


Desoxypeganine and its pharmaceutically acceptable acid addition salts can be used in the treatment of alcoholism. Said substances are administered preferably in a continuos and controlled manner. The pharmaceutical administration form enables controlled release, e.g. for oral, transdermal or another route of parenteral administration.

Deoxypeganine and its pharmaceutically acceptable acid addition salts can be used for the treatment of alcoholism. These substances are preferably administered in a continuous and controlled manner. The pharmaceutical administration form makes controlled release possible for, for example, oral, transdermal or alternatively parenteral administration.
The invention relates to the use of deoxypeganine and its pharmaceutically suitable acid addition salts for the treatment of alcoholism. These compounds are released in a continuous and controlled manner from appropriate pharmaceutical formulations, which are administered, for example, orally, transdermally or otherwise parenterally.
In particular, the present invention makes pharmaceutical formulations available which release suitable compounds for the treatment of alcoholism in a controlled manner.
While acute withdrawal in alcohol-dependent patients and the treatment of life-endangering withdrawal delirium in special wards is no longer a medical problem today, there is still no satisfactory treatment of chronic alcoholism. About 80% of the treated alcoholics relapse within a year. They need help by means of a reliably acting and highly tolerable agent against the desire for alcohol which leads to the relapse.
In spite of the human problems and of the immense national economic damage associated with the problem of chronic alcoholism, innovation in the medicinal treatment of chronic alcoholism is stagnating worldwide and very particularly in the Federal Republic of Germany.
In the case of the pharmaceuticals which are employed for the control of the effects of alcohol and of alcoholism, the following must be differentiated:
1. Sobering-up agents (amethysts).
2. Agents for the treatment of life-threatening alcohol intoxication, e.g. naloxone (Narcanti), physostigmine.
3. Pharmaceuticals for making acute alcohol withdrawal easier, e.g. neuroleptics (Neurocil, Melleril), piracetam, clonidine, carbamazepine, and withdrawal delirium: clomethiazole (Distraneurin).
4. Substances which block the degradation of alcohol at the acetaldehyde stage and as a result produce an artificial alcohol intolerance. Disulfiram (Antabuse), the main representative of this group, is the medicament which is employed most frequently for the treatment of alcoholism. Antabuse, however, is not a therapeutic, as this and related substances decrease neither the desire for alcohol nor influence the causes of the condition.
5. Agents which are intended to satisfy the compulsive desire for alcohol (the craving) and thus to prevent the relapse of the treated alcoholics. There is an urgent need, in particular, for these agents, but an efficacious medicament for the treatment of chronic alcoholism has still not been found.
Clinical trials with fenfluoramine and bromocriptine have not been repeated and confirmed.
The great hopes which had been placed in the lithium therapy of chronic alcoholism have not been fulfilled.
The best results yet have been achieved with zimelidine, but this serotonin reuptake inhibitor, which was marketed as an antidepressant under the name Normud, had to be withdrawn because of serious side effects and is no longer available. Galanthamine, an alkaloid from Amaryllidaceae, is still being clinically tested at present.
The object of the invention is therefore the provision of a pharmaceutical which, by controlled release of an oral, transdermal or otherwise parenteral formulation, makes an efficacious and practical treatment of alcoholism possible by decreasing the desire for alcohol.
This object is achieved according to the invention by a formulation and its use for the treatment of alcoholism, which formulation comprises an efficacious amount of the active compound deoxypeganine (1,2,3,9-tetrahydropyrrolo[2,1-b]quinazoline) and/or one of its pharmaceutically tolerable acid addition salts.
This achievement is all the more surprising as the pharmacological actions of deoxypeganine have in fact been intensively investigated in the former USSR, but the action of a deoxypeganine-containing formulation, attributed to deoxypeganine, of decreasing the desire of alcoholics for alcohol has not been described up to now.
Deoxypeganine is obtained by isolation from the harmel peganum (Peganum harmala) or by synthesis.
On account of its pharmacological properties, deoxypeganine belongs to the group of reversibly acting cholinesterase inhibitors. It is closely related in its actions to physostigmine, neostigmine and galanthamine, but also has specific properties. Deoxypeganine inhibits not only the degradation of acetylcholine, but also that of dopamine.
This advantage offsets its somewhat lower dose-related cholinesterase inhibitory action. Deoxypeganine was intended in the former Soviet Union as an antidote and prophylactic in poisoning by organic thiophosphoric acid esters.
In contrast to neostigmine, deoxypeganine crosses the blood-brain barrier and antagonizes the cerebral action of cholinergic toxins.
The present invention is directed at formulations by means of which deoxypeganine or one of its pharmaceutically acceptable acid addition salts are released in a continuous, controlled manner.
Pharmaceutical forms which release active compounds in a controlled manner are known in the prior art. The administration of pharmaceutically active compounds by means of such formulations can be carried out orally, transdermally or otherwise parenterally.
The formulations for oral administration suitable in the context of the present invention are described below.
In such a formulation, the pharmaceutical active compound is encapsulated in a semipermeable membrane, e.g. of cellulose acetate. A tiny hole is drilled in the capsule material using a drill or a laser. Water is absorbed by the capsule material in the body of the patient who is being treated. The pharmaceutical active compound is gradually driven through the small opening by osmotic pressure in the desired, constant and controlled manner. Such systems are described in U.S. Pat. Nos. 3,760,805, 3,760,806, 3,764,984, 3,845,770, 3,916,899 and 3,987,790. In these systems, the pharmaceutical active compounds can be present in solid form or absorbed on ion exchanger resins.
Another system for oral administration according to the present invention is described by Sheth and Leeson in U.S. Pat. No. 4,137,300. This patent describes a formulation which comprises a wax matrix.
The active compounds of the present invention are administered in a fitting and suitable manner by means of appropriate formulations. The solid active compounds can be administered in solution or as a dispersion. The solution or dispersion medium can be inorganic or organic. Suitable solution or suspension media for deoxypeganine are, for example, water, silicone oil or mineral oil.
Silicone oils are understood here as meaning linear-polymeric dimethylsiloxanes and mineral oils are understood as meaning the distillation products obtained from mineral raw materials (petroleum, lignite tar and coal tar, wood, peat), which essentially consist of mixtures of saturated hydrocarbons.
In order to make the administration of a compound by means of a formulation as described above possible, the following additives can be added to the system:
antioxidants, synergists, stabilizers,
preservatives,
flavor corrigents,
colorants,
solvents, solubilizers,
surfactants (emulsifiers, solubilizers, wetting agents, antifoams),
viscosity- and consistency-influencing agents, gel-forming agents,
absorption accelerators,
adsorption agents,
moisture retention agents,
lubricants (e.g. flow-regulating agents),
disintegration- and solution-influencing agents,
fillers (extenders),
peptizing agents,
release-delaying agents.
This list makes no claim to completeness. Many substances fulfil not only one function, they are therefore to be assigned to a number of the excipient groups mentioned. Thus, for example, types of starch are used as fillers in tablet and powder production. However, at the same time they are flow-regulating agents, adsorption agents, hydrogel-forming agents and viscosity enhancers.
The suitable, physiologically acceptable substances are known to the person skilled in the art.
In a formulation for the transdermal administration of compounds according to the present invention, the pharmaceutical active compound can be contained in a matrix from which it is released in the desired gradual, constant and controlled manner. The permeability of the matrix during the release of the compound is based on diffusion. A system of this type is described in German Patent DE 33 15 272. This system consists of an impermeable back layer, a specially constructed supersaturated active-compound reservoir associated with it, made of a polymer matrix, a contact-adhesive layer permeable to the active compound, associated with the reservoir, and a protective layer which can be removed again for use, covering the contact-adhesive layer. Systems in which the reservoir layer has such a high intrinsic tackiness that it is simultaneously the contact-adhesive layer are also possible.
If the active compound is absorbed through the skin, the patient to be treated in this way receives a controlled and predeterminable supply of the active compound.
Other suitable transdermal formulations are described in U.S. Pat. Nos. 3,742,951, 3,797,494, 3,996,934 and 4,031,894. These formulations fundamentally consist of a back layer, which is one of the surfaces, an adhesive layer permeable to the active compound, which is the other surface, and finally a reservoir which comprises the active compound between the two layers forming the surfaces. Alternatively to this, the active compound can also be contained in a multiplicity of microcapsules which are distributed within the permeable adhesive layer. In each case, the active compound is continuously released from the reservoir or the microcapsules through a membrane into the adhesive layer permeable to the active compound, which is in contact with the skin or mucosa of the patient to be treated. In the case of microcapsules, the capsule material can also act as a membrane.
Formulations which are suitable for the otherwise, parenteral administration of deoxypeganine and its salts are those which permit a depot action of the active compound. In this context, the formulation is administered as an injection solution on a nonaqueous basis. The possible solvents are known to the person skilled in the art. Examples which may be mentioned are the vegetable oils which individual pharmacopeias prescribe. Peanut oil, olive oil, almond oil, sunflower oil, soybean oil and sesame oil are prominent. Castor oil often shows a particularly favorable solubility for medicaments; in addition oils of animal origin are also suitable. The oils are physiologically indifferent and highly tolerable. The prerequisite for this is that they are specially purified and have low acid and peroxide counts. As intravenous administration is not possible because of the lack of miscibility with the blood serum and can lead to pulmonary embolism, only their use for intramuscular and subcutaneous injection preparations is possible. Oily solutions and suspensions remain at the site of administration for a very long time (often up to 1 month) and release the active compounds over a prolonged period.
The dose of deoxypeganine or its pharmaceutically acceptable acid addition salts must be so high that a lasting action is achieved and needs individual adjustment. The active compound content of the present formulation is preferably between 0.1 and 90% by weight, in particular preferably between 5 and 20% by weight, based on the total weight of the formulation.

Pharmaceutical composition containing desoxypeganine for the treatment of alcoholism


A capacitive physical-quantity detection apparatus includes a movable electrode (2d) which is displaced in response to a physical quantity. A fixed electrode (3, 4) opposed to the movable electrode forms a capacitor in conjunction with the movable electrode. A signal applying device (23, 24) operates for applying a first signal between the movable electrode and the fixed electrode. The first signal is periodic, and has at least a first time period for detection of a capacity variation and a second time period for displacement of the movable electrode to implement self diagnosis. A C-V conversion circuit (21) operates for generating a voltage which depends on a variation in a capacitance of the capacitor during the first time period. A signal processing circuit (22) operates for processing the voltage generated by the C-V conversion circuit into a second signal depending on the physical quantity. A changing device (23) operates for changing the first signal in the second time period between a state for execution of self diagnosis and a state for unexecution of self diagnosis. The first signal in the state for execution of self diagnosis applies a pseudo physical quantity to the movable electrode.

1. Field of the Invention
This invention relates to a capacitive-type apparatus for detecting a physical quantity such as an acceleration, an angular velocity, or a pressure.
2. Description of the Related Art
In a typical capacitive physical-quantity detection apparatus, a movable electrode and a fixed electrode are opposed to each other to form a capacitor, and a physical quantity is detected on the basis of the capacitance of the capacitor.
There are known capacitive physical-quantity detection apparatuses of various types which are designed to implement self diagnoses. In a self-diagnosis mode of operation of such a known apparatus, an electrostatic force is generated between a movable electrode and a fixed electrode to produce a state where a pseudo physical quantity is deemed to be acting on the movable electrode.
Self diagnosis is carried out by inspecting a response of an apparatus sensing portion to the pseudo physical quantity.
Japanese published unexamined patent application 5-322921 corresponding to U.S. Pat. No. 5,506,454 discloses a system for diagnosing characteristics of a capacitive acceleration sensor. In a diagnosis mode of operation of the system, a signal applicator serves as a means for applying a diagnosis signal to a fixed electrode so that a force corresponding to an acceleration is exerted onto a movable electrode. Diagnosis is carried out by inspecting a response of the sensor to the acceleration-corresponding force.
U.S. Pat. No. 5,540,095 discloses an accelerometer including two fixed electrodes opposed to a movable electrode. In a self-test mode of operation of the accelerometer, a carrier voltage level fed to one of the fixed electrodes is made different from a normal value to apply a pseudo physical quantity to the movable electrode. Self test is implemented by inspecting a response of an accelerometer sensing portion to the applied pseudo physical quantity.
U.S. Pat. No. 5,583,290 discloses a micromechanical sensing apparatus including two fixed electrodes opposed to a movable electrode. During a normal mode of operation of the apparatus, carrier signals having different center voltages are applied to the fixed electrodes respectively, and detection is made as to the capacitance of a capacitor formed by the fixed electrodes and the movable electrode. In a self-test mode of operation of the apparatus, a voltage fed to the movable electrode is made different from a normal value to apply a pseudo physical quantity to the movable electrode. Self test is implemented by inspecting a response of an apparatus sensing portion to the applied pseudo physical quantity.

Capacitive physical-quantity detection apparatus