A detergent tablet for fabric washing is compacted from a particulate composition containing detergent active compound, detergency builder, a bleach system comprising coated sodium percarbonate and at least one bleach activator, and optionally other detergent ingredients, where the tablet comprises a plurality of discrete regions, and wherein the bleach activator and the coated sodium percarbonate are concentrated in respective different regions of the tablet. This separation of activator and percarbonate increases the stability of the bleach activator.

This invention relates to tablets of compacted particulate detergent composition suitable for washing fabrics.
Detergent compositions in tablet form have been described in a number of documents including, for example, GB 911204 (Unilever), WO 90/02165 (Henkel) and EP-A-711827 (Unilever) and are sold now commercially. Tablets have several advantages over powdered products: they do not require measuring and are thus easier to handle and dispense into the washload, and they are more compact, hence facilitating more economical storage.
One issue that has been considered in the formulation of detergent tablets is the incorporation of bleaching ingredients, especially when the presence of bleach-sensitive ingredients such as enzymes and perfume is also desired. In a compressed tablet, the ingredients are much more intimately associated with one another than in a powder, and it would be foreseen that any adverse interactions and instability will be exacerbated.
It has become commonplace to use an inorganic peroxygen bleach jointly with a bleach activator. The latter is usually an organic compound which reacts with the peroxygen bleach in the wash liquor to generate a bleaching species such as peracetic acid which is effective at lower wash temperature than the bleach.
EP 737 738 (Clean tabs) discloses bleach tablets comprising coated sodium percarbonate and a bleach activator (TAED). However, this document does not teach the separation of the percarbonate and the bleach activator. The bleach tablets are intended to be used together with usual textile detergent compositions.
EP 0 481 793A (Unilever) is aimed at solving the particular storage problems that arise when sodium percarbonate, Na2CO3.1.5H2O2, is included in a tablet formulation. This persalt is less stable than sodium perborate in the presence of moisture, and hence more readily undergoes premature decomposition in which hydrogen peroxide is liberated and this decomposes readily. The solution proposed is to separate the sodium percarbonate from any other ingredient of the composition detrimental to its stability by segregation in a discrete region of the tablet.
This segregation can be achieved by isolating the percarbonate in a region of the tablet which may be a layer, core or insert, while other ingredients are present in other region(s), which may be other layers or the main body or matrix of the tablet. Alternatively, it is suggested that the percarbonate is present in regions which are relatively large granules or noodles distributed throughout the main body or matrix of the tablet, the granules or noodles being protected by coating or encapsulation with a water-soluble material.
Examples in the application demonstrated that percarbonate decomposition occurs even in the absence of bleach activator and is reduced when the percarbonate is segregated into discrete region(s).
EP 481 792 (Unilever) discloses a laundry detergent tablets containing a particulate bleaching composition which may comprise a bleach activator.
GB 911 204 (Unilever) discloses layered detergent tablets containing persalt bleach, for example, sodium perborate, and certain bleach activators, for example, sodium acetoxybenzene sulphonate and phthalic anhydride. To avoid destabilisation, the bleach activator is segregated from the remaining tablet ingredients, including persalt bleach.
Segregation is achieved by putting the bleach activator in a separate section or layer.
In contrast, EP 395 333A (Unilever) disclosed detergent tablets containing sodium perborate in conjunction with one or more bleach-sensitive ingredientsxe2x80x94tetraacetylethylenediamine (TAED) or similar bleach activator, enzyme, fluorescer, or any combination of thesexe2x80x94as well as detergent-active compound, detergency builders and optionally other ingredients. The persalt is not segregated from the bleach-sensitive ingredients.
This document taught that segregation of bleach activator from the perborate bleach was not necessary for TAED and similar activators. When compositions were prepared containing both perborate and TAED together, and then stored either as powders or as tablets compacted from those powders, a loss of bleaching activity during storage was observed but there was no significantly greater loss in tablets. In a number of instances the tablets showed better bleaching after storage than did powders where the ingredients are not in such close proximity.
This document also showed a similar finding when enzymes were incorporated in powders with the bleaching system and a comparison was made of enzyme stability both in these powders and in tablets compacted from the powders. During storage the decomposition of enzyme in tablets, where the compaction had necessarily brought the enzyme into closer proximity with the bleaching system was not significantly greater and in some cases was less than observed with powders.
WO 99/35225 and WO 99/35229 to WO 99/35236 (Henkel) all disclose segregation of ingredients within double layer laundry detergent tablets.
Surprisingly, it has now been found that the stability of the bleach sensitive ingredients can be further increased by encapsulating the sodium percarbonate and in addition segregating these sensitive ingredients from (encapsulated) sodium percarbonate, even though stability of percarbonate is not much affected by such xe2x80x9cdouble segregationxe2x80x9d. Therefore, in a first aspect, the present invention provides a tablet of compacted particulate detergent composition comprising a detergent-active compound, a detergency builder, a bleach system comprising sodium percarbonate in the form of particles having a coating of water-soluble material together with bleach activator which is preferably at least one bleach activator selected from N-diacylated and N,Nxe2x80x2-polyacylated amine bleach activators, and optionally other detergent ingredients, which tablet comprises a plurality of discrete regions, each of which is at least 10% of the total weight of the tablet, and wherein the bleach activators and the particles containing the sodium percarbonate within a water-soluble coating are concentrated in respective different regions of the tablet.
In a second aspect, the present invention provides a tablet of compacted particulate detergent composition comprising a detergent active compound, a detergency builder, a bleach system comprising sodium percarbonate in the form of particles having a coating of water-soluble material, at least one enzyme and optionally other detergent ingredients, where the tablet comprises a plurality of discrete regions each of which is at least 10% of the total weight of the tablet and wherein the said enzyme and the particles containing the sodium percarbonate within a water-soluble coating are concentrated in respective different regions of the tablet.
It will be appreciated that in this invention both bleach activator and enzyme may be incorporated in the same region(s) of the tablet while sodium percarbonate is concentrated in a different region or regions.
Preferably a region or regions in which sodium percarbonate is concentrated contain at least 80% better at least 90% or 95% of the sodium percarbonate present in the tablet and better still all of it. It is preferred that such regions contain at most 20% of all the bleach activator and/or at most 20% of a detergent enzyme present in the tablet, more preferably less than this. Correspondingly a region or regions in which bleach activator is concentrated or in which an enzyme is concentrated preferably contain at least 80% of the bleach activator or respectively enzyme present in the tablet more preferably at least 90% or 95% of the bleach activator or enzyme and at most 20% preferably at most 10% or 5% of the percarbonate present in the tablet.
If more than one enzyme is used in a tablet, it is possible but not preferred, to segregate one enzyme but not segregate another enzyme from the coated percarbonate. Preferably all the enzyme types present are segregated together so that one or more regions contain at least 90 or 95% of all enzyme but not more than 20% of the percarbonate. There may well be complete segregation so that regions which contain bleach, enzyme, or both, are free of percarbonate.
As will be mentioned in more detail below, tablets of this invention may contain water-soluble or water-insoluble detergency builder but the invention is particularly applicable to tablets which contain water-insoluble aluminosilicate detergency builder. The discrete region(s) are preferably in the form of layers of the tablet having two or more layers but other possibilities also exist.
Materials which may be incorporated in tablets of this invention, preferences concerning these materials, and other features will now be described and exemplified in more detail.
Discrete Regions
The discrete regions may be in the form of layers, and a tablet with two layers is one preferred embodiment of the present invention. One layer of this two-layer tablet contains the coated sodium percarbonate particles, and the other layer the particles of the bleach activator. Each layer of such a tablet is preferably substantially homogeneous, that is to say, is the compaction product of a single particulate composition, although that particulate composition may have been prepared by mixing a number of components and all its particles will not necessarily be identical. Typically, such a two-layer tablet is made on a tableting press by part filling the die with the composition of the first layer, pressing this layer, and then adding the composition of the second layer before pressing the tablet for a second time. It is preferred that the two layers of this tablet are not equal in sizexe2x80x94a weight ratio of 10:90 to 40:60 is preferable, and a ratio of 20:80 to 30:70 is more preferred, with a ratio of 25:75 being most preferred. Usually, the percarbonate particles are present in the larger layer.
An alternative preferred embodiment of the invention is a tablet which has a pair of opposite faces spaced apart from each other and joined by a peripheral surface of the tablet, wherein the tablet is subdivided into at least two regions which are each visible at a said face. One such tablet is one having a central core passing through the whole tablet. One particular method of manufacturing such tablets is described in our copending application, GB 9901688.3.
Other forms of discrete regions are known for detergent tablets and are included in the present invention, and include cores which do not pass all the way through the tablet and a central region completely enclosed by an outer region.
Sodium Percarbonate Granules
The granules of sodium percarbonate used in the present invention require a coating of water-soluble material. Suitable coating materials should be water-soluble, and not sensitive to the presence of bleach. They include sodium sulphate, sodium carbonate, sodium chloride and sodium borate. It is possible that the coating material will be a mixture of such materials.
It is unlikely that the coating material will exceed 20% by weight of the whole granule. Typically, the coating material will be less than 5% by weight of the whole granule, preferably less than 3% by weight. The minimum amount of coating material is determined by the requirement that the sodium percarbonate is fully encapsulated, but is likely to be at least 1% by weight, more preferably 2% by weight.
Coated sodium percarbonate granules are commercially available for example from Solvay, who manufacture granules coated with a sodium carbonate/sodium chloride mixture and Kemira who supply granules coated with sodium sulphate.
Bleach Activator
Preferred bleach activators are acylated amine bleach activators which have been widely disclosed in the art. Preferred examples include peracetic acid precursors, for example tetraacetylethylene diamine (TAED), which is widely used in detergent powders.
A bleach activator is required in tablets of the first aspect of the present invention, but may also be present in tablets of the second aspect. Bleach activator is usually present in an amount from 1 to 10% by weight of the tablet.
Other Bleach System Ingredients
A bleach system may also include a bleach stabiliser (heavy metal sequestrant) such as ethylenediamine tetramethylene phosphonate, diethylenetriamine pentamethylene phosphonate, and ethylenediamine disuccinate (EDDS).
Perfumes
Perfumes are known to be sensitive to the presence of bleaching systems and show a surprising increase in storage stability in tablets of the first aspect of the present invention, compared to tablets where only one form of segregation of the sodium percarbonate and bleach activator is used. Thus it is preferred that tablets of the first aspect contain a perfume. This perfume nay be present in only one region of the tablet, but can be present in the region containing coated percarbonate, and may be present throughout the whole tablet.
As is well known, a perfume normally consists of a mixture of a number of perfumery materials, each of which has a fragrance. The number of perfumery materials in a perfume is typically ten or more. The range of fragrant materials used in perfumery is very wide; the materials come from a variety of chemical classes, but in general are hydrophobic oils. In many instances, the molecular weight of a perfumery material is in excess of 150, but does not exceed 300.
Although the invention is not limited to specific perfumery materials, some perfumery materials which may be used include: acetyl cedrene; 4-acetoxy-3-pentyltetrahydropyran; 4-acetyl-6-t-butyl-1,1-dimethylindane, available under the trademark xe2x80x9cCELESTOLIDExe2x80x9d; 5-acetyl-1,1,2,3,3,6-hexamethylindane, available under the trademark xe2x80x9cPHANTOLIDExe2x80x9d; 6-acetyl-1-isopropyl-2,3,3,5-tetramethylindane, available under the trademark xe2x80x9cTRASEOLIDExe2x80x9d; alpha-n-amylcinammic aldehyde; amyl salicylate; aubepine; aubepine nitrile; aurantion; 2-t-butylcyclohexyl acetate; 2-t-butylcyclohexanol; 3-(p-t-butylphenyl)propanal; 4-t-butylcyclohexyl acetate; 4-t-butyl-3,5-dinitro-2,6-dimethyl acetophenone; 4-t-butylcyclohexanol; benzoin siam resinoids; benzyl benzoate; benzyl acetate; benzyl propionate; benzyl salicylate; benzyl isoamyl ether; benzyl alcohol; bergamot oil; bornyl acetate; butyl salicylate; carvacrol; cedar atlas oil; cedryl methyl ether; cedryl acetate; cinnamic alcohol; cinnamyl propionate; cis-3-hexenol; cis-3-hexenyl salicylate; citronella oil; citronellol; citronellonitrile; citronellyl acetate: citronellyloxyacetaldehyde; cloveleaf oil; coumarin; 9-decen-1-ol: n-decanal; n-dodecanal; decanol; decyl acetate; diethyl phthalate; dihydromyrcanol; dihydromyrcenyl formate; dihydromyrcenyl acetate; dihydroterpinyl acetate; dimethylbenzyl carbinyl acetate; dimethylbenzylcarbinol; dimethylheptanol; dimyrcatol; diphenyl oxide; ethyl naphthyl ether; ethyl vanillin; ethylene brassylate; eugenol; geraniol; geranium oil; geranonitrile; geranyl nitrile; geranyl acetate; 1,1,2,4,4,7-hexamethyl-6-acetyl-1,2,3,4-tetrahydronaphthalene, available under the trademark xe2x80x9cTONALIDxe2x80x9d; 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-2-benzopyran, available tinder the trademark xe2x80x9cGALAXOLIDExe2x80x9d; 2-n-heptylcyclopentanone; 3a,4,5,6,7,7a-hexahydro-4,7-methano-1(3)H-inden-6-ylpropionate, available under the trademark xe2x80x9cFLOROCYCLENExe2x80x9d; 3a,4,5,6,7,7a-hexahydro-4,7-methano-1(3)H-inden-6-ylacetate, available under the trademark xe2x80x9cJASMACYCLENExe2x80x9d; 4-(4xe2x80x2-hydroxy-4xe2x80x2-methylpentyl)-3-cyclohexenecarbaldehyde; alpha-hexylcinammic aldehyde; heliotropin; Hercolyn D; hexyl aldone; hexyl cinnamic aldehyde; hexyl salicylate; hydroxycitronellal; i-nonyl formate; 3-isocamphylcyclohexanol; 4-isopropylcyclohexanol; 4-isopropylcyclohexyl methanol; indole; ionones; irones; isoamyl salicylate; isoborneol; isobornyl acetate; isobutyl salicylate; isobutylbenzoate; isobutylphenyl acetate; isoeugenol; isolongifolanone; isomethyl ionones; isononanol; isononyl acetate; isopulegol; lavendin oil; lemongrass oil; linalool; linalyl acetate; LRG 201; 1-menthol; 2-methyl-3-(p-isopropylphenyl)propanal; 2-methyl-3-(p-t-butylphenyl)propanal; 3-methyl-2-pentyl-cyclopentanone; 3-methyl-5-phenyl-pentanol; alpha and beta methyl naphthyl ketones; methyl ionones; methyl dihydrojasmonate; methyl naphthyl ether; methyl 4-propyl phenyl ether; Mousse de chene Yugo; Musk ambrette; myrtenol; naroli oil; nonanediol-1;3-diacetate; nonanol; nonanolide-1,4, nopol acetate; 1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-acetyl-naphthalene, available under the trademark xe2x80x9cISO-E-SUPERxe2x80x9d; octanol; Oppoponax resinoid; orange oil; p-t-amylcyclohexanone; p-t-butylmethylhydrocinnamic aldehyde; 2-phenylethanol; 2-phenylethyl acetate; 2-phenylpropanol; 3-phenylpropanol; para-menthan-7-ol; para-t-butylphenyl methyl other; patchouli oil: pelargene; petitgrain oil; phenoxyethyl isobutyrate; phenylacetaldehyde diethyl acetal; phenylacetaldehyde dimethyl acetal; phenylethyl n-butyl ether; phenylethyl isoamyl ether; phenylethylphenyl acetate; pimento leaf oil; rose-d-oxide; Sandalone; styrallyl acetate) 1,1,4,4-tetramethyl-6-acetyl-7-ethyl-1,2,3,4-tetrahydronaphthalene, available under the trademark xe2x80x9cVERSALIDExe2x80x9d; 3,3,5-trimethyl hexyl acetate; 3,5,5-trimethylcyclohexanol; terpineol; terpinyl acetate; tetrahydrogeraniol; tetrahydrolinalool; tetrahydromuguol; tetrahydromyrcenol; thyme oil; trichloromethylphenycarbinyl acetate; tricyclodecenyl acetate; tricyclodecenyl propionate; 10-undecen-1-al; gamma undecalactone; 10-undecen-1-ol undecanol; vanillin; vetiverol; vetiveryl acetate; vetyvert oil; acetate and propionate esters of alcohols in the list above; aromatic nitromusk fragrances; indane musk fragrances; isochroman musk fragrances; macrocyclic ketones; macrolactone musk fragrances; and tetralin musk fragrances.
Perfumes frequently include solvents or diluents, for example: ethanol, isopropanol, diethylene glycol monoethyl ether, dipropylene glycol, diethyl phthalate and triethyl citrate.
Perfumes which are used in this invention may, if desired, have deodorant properties as disclosed in U.S. Pat. No. 4,303,679, U.S. Pat. No. 4,663,068 and EP-A-545556.
These perfumes may be incorporated into the particulate composition to be compacted by conventional means, such as by spraying onto the composition, or by adsorption onto a solid carrier which is incorporated into the composition. One particular type of perfume-containing particles is described in WO 96/21719 (Unilever).
Enzymes
The tablets of the first aspect of the present invention may contain one of the detergency enzymes well known in the art for their ability to degrade various soils and stains and so aid in their removal. An enzyme is a required constituent of tablets according to the second aspect of the invention.
Suitable enzymes include various proteases, cellulases, lipases, amylases, oxidases and mixtures thereof, which are designed to remove a variety of soils and stains from fabrics. Cellulases have a fabric softening function also. Detergency enzymes are commonly employed in the form of particles or marumes, optionally with a protective coating, in amount of from about 0.01% often from 0.1% to about 3% by weight of the tablet. A total enzyme content may exceed 3% but is unlikely to exceed 5%. The amount of any one enzyme is likely to tie in a range from 0.01% to 3% by weight of the whole tablet.
Detergent-active Compounds
Detergent-active compounds are suitably present in an amount of from 2% or 5% up to 50 wt %, more preferably from 5% or 8% up to 40 wt % of the whole tablet. These will most usually be anionic and nonionic surfactants and mixtures of the two. Amphoteric (including zwitterionic) and less commonly cationic detergents can also be used.
Anionic Surfactant Compounds
Synthetic (i.e. non-soap) anionic surfactants are well known to those skilled in the art. The anionic surfactant may comprise, wholly or predominantly, linear alkyl benzene sulphonate of the formula
where R is linear alkyl of 8 to 15 carbon atoms and M+ is a solubilising cation, especially sodium.
Primary alkyl sulphate having the formula
ROSO3xe2x88x92M+
in which R is an alkyl or alkenyl chain of 8 to 18 carbon atoms especially 10 to 14 carbon atoms and M+ is a solubilising cation, is also commercially significant as an anionic surfactant and may be used in this invention.
Frequently, such linear alkyl benzene sulphonate or primary alkyl sulphate of the formula above, or a mixture thereof will be the desired non-soap anionic surfactant and may provide 75 to 100 wt % of any anionic non-soap surfactant in the composition.
Examples of other non-soap anionic surfactants include olefin sulphonates; alkane sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates.
One or more soaps of fatty acids may also be included in addition to non-soap anionic surfactant. Examples are sodium soaps derived from the fatty acids from coconut oil, beef tallow, sunflower or hardened rapeseed oil.
Nonionic Surfactant Compounds
Nonionic surfactant compounds include in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide.
Specific nonionic surfactant compounds are alkyl (C8-22) phenol-ethylene oxide condensates, the condensation products of linear or branched aliphatic C8-20 primary or secondary alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylene-diamine.
Especially preferred are the primary and secondary alcohol ethoxylates, especially the C9-11 and C12-15 primary and secondary alcohols ethoxylated with an average of from 3 to 20 moles of ethylene oxide per mole of alcohol.
Amphoteric Surfactants
Amphoteric surfactants which may be used jointly with anionic or nonionic surfactants or both include amphopropionates of the formula:
where RCO is a acyl group of 8 to 18 carbon atoms, especially coconut acyl.
The category of amphoteric surfactants also includes amine oxides and also zwitterionic surfactants, notably betaines of the general formula
where R4 is an aliphatic hydrocarbon chain which contains 7 to 17 carbon atoms, R2 and R3 are independently hydrogen, alkyl of 1 to 4 carbon atoms or hydroxyalkyl of 1 to 4 carbon atoms such as CH2OH,
Y is CH2 or of the form CONHCH2CH2CH2 (amidopropyl betaine);
Z is either a COOxe2x88x92 (carboxybetaine), or of the form CHOHCH2SO3xe2x80x94 (sulfobetaine or hydroxy sultaine).
Another example of amphoteric surfactant is amine oxide of the formula
where R1 is C10 to C20 alkyl or alkenyl
R2, R3 and R4 are each hydrogen or C1 to C4 alkyl while n is from 1 to 5.
Detergency Builder
The detergent tablets of the invention contain one or more detergency builders, suitably in an amount of from 5 to 80 wt %, preferably from 20 to 80 wt %. These builders may be either water-soluble or water-insoluble, and a mixture of the two is also included within the scope of the present invention.
Water-soluble phosphorus-containing inorganic detergency builders include the sodium and potassium orthophosphates, metaphosphates, pyrophosphates and polyphosphates.
Alkali metal aluminosilicates are strongly favoured as environmentally acceptable water-insoluble builders for fabric washing. Alkali metal (preferably sodium; aluminosilicates may be either crystalline or amorphous or mixtures thereof, having the general formula:
0.8-1.5Na2O.Al2O3.0.8-6SiO2.xH2O
These materials contain some bound water (indicated as xe2x80x9cxH2Oxe2x80x9d) and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5-3.5 SiO2 units (in the formula above). Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature.
Suitable crystalline sodium aluminosilicate ion-exchange detergency builders are described, for example, in GB 1429143 (Procter and Gamble). The preferred sodium aluminosilicates of this type are the well known commercially available zeolites A and X, the zeolite P described and claimed in EP 384070 (Unilever) which is also referred to as zeolite MAP and mixtures thereof. Zeolite MAP is available from Crosfields under their designation Zeolite A24.
Conceivably, water-insoluble detergency builder could be a crystalline layered sodium silicate as described in U.S. Pat. No. 4,664,839.
NaSKS-6 is the trademark for a crystalline layered silicate marketed by Hoechst (commonly abbreviated as xe2x80x9cSKS-6xe2x80x9d). NaSKS-6 has the delta-Na2SiO5 morphology form of layered silicate. It can be prepared by methods such as described in DE-A-3,417,649 and DE-A-3,742,043. Other such layered silicates, which can be used have the general formula NaMSixO2x+1.yH2O wherein M is sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, and y is a number from 0 to 20, preferably 0.
Crystalline layered silicate may be used in the form of granules which also contain citric acid.
Non-phosphorous water-soluble builders may be organic or inorganic. Inorganic builders that may be present include alkali metal (generally sodium) carbonate; while organic builders include polydarboxylate polymers, such as polyacrylates and acrylic/maleic copolymers, monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono- di- and trisuccinates, carboxymethyloxysuccinates, carboxymethyloxymalonates, dipicolinates and hydroxyethyliminodiacetates.
Alkali metal silicate, particularly sodium ortho-, meta- or disilicate has detergency building properties and may be used in substantial quantity in tablets for machine dishwashing. It is desirably included in smaller quantities in tablets for fabric washing. The presence of such alkali metal silicates may be advantageous in providing protection against the corrosion of metal parts in washing machines, besides providing some detergency building.
The detergency builder may also comprise an organic builder such as NTA (trisodium nitrilotriacetate monohydrate).
Tablet compositions preferably include polycarboxylate polymers, more especially polyacrylates and acrylic/maleic copolymers which can function as builders and also inhibit unwanted deposition onto fabric from the wash liquor.
If a composition is formulated to have low phosphate, the amount of inorganic phosphate builder may be less than 5 wt % of the tablet composition.
Disintegrants
A tablet of this invention may include a material which functions as a disintegrant. Such a material may be such as to swell on contact with water, thus subjecting the compacted tablet composition to internal pressure.
A number of materials are known for use as swelling disintegrants in pharmaceutical tablets and these may be used in detergent tablets of this invention. Examples include organic materials such as starches, for example, corn, maize, rice and potato starches and start derivatives, such as Primojel (Trade Mark) carboxymethyl starch and Explotab (Trade Mark) sodium starch glycolate; celluloses and cellulose derivatives, for example, Courlose (Trade Mark) and Nymcel (Trade Mark) sodium carboxymethyl cellulose, Ac-di-Sol (Trade Mark) cross-linked modified cellulose, and Hanfloc (Trade Mark) microcrystalline cellulosic fibres; and various synthetic organic polymers, notably cross-linked polvinyl pyrrolidone, for example, Polyplasdone (Trade Mark) Xl or Kollidon (Trade Mark) CL. Inorganic swelling disintegrants include bentonite clay.
Polymer Binder
Tablets of this invention may include an organic water-soluble polymer, serving as a binder when the particles are compacted into tablets. This polymer may be a polycarboxylate included as a supplementary builder, as mentioned earlier. It may be applied as a coating to some or all of the constituent particles prior to compaction.
As taught in our EP-A-522766, such polymers can function to enhance tablet disintegration at the time of use, as well as acting as a binder to enhance tablet strength prior to use.
It is preferred that such a binder material, if present, should melt at a temperature of at least 35xc2x0 C., better at 40xc2x0 C. or above, which is above ambient temperatures in many temperate countries. For use in hotter countries it will be preferred that the melting temperature is somewhat above 40xc2x0 C., so as to be above the ambient temperature.
For convenience the melting temperature of the binder material should be below 80xc2x0 C.
Preferred binder materials are synthetic organic polymers of appropriate melting temperature, especially polyethylene glycol. Polyethylene glycol of average molecular weight 1500 (PEG 1500) melts at 45xc2x0 C. and has proved suitable. Polyethylene glycol of higher molecular weight, notably 4000 or 6000, can also be found.
Other possibilities are polyvinylpyrrolidone, and polyacrylates and water-soluble acrylate copolymers.
The binder may suitably be applied to the particles by spraying, e.g. so as a solution or dispersion. It may be applied to particles which contain organic surfactant. If used, the binder is preferably used in an amount within the range from 0.1 to 10% by weight of the tablet composition, more preferably the amount is at least 1% or even at least 3% by weight of the tablets. Preferably the amount is not over 8% or even 6% by weight unless the binder serves some other additional function.
Water-soluble Disintegrants
Published patent applications have revealed that certain water-soluble materials function to promote tablet disintegration at the time of use and such materials may be used in tablets of this invention so as an alternative to, or in addition to, and insoluble but water-swellable disintegrant.
Such materials include compounds of high water-solubility, a specified form of sodium tripolyphosphate and combinations of these two. Such material may be present as at least 10 or 15% of the composition of a tablet or region thereof, possibly at least 25% up to 50 or 60%, possibly more.
Highly water soluble materials, which are one of the two possibilities are compounds, especially salts, with a solubility at 20xc2x0 C. of at least 50 gms per 100 gms of water.
Such materials have been mentioned in our published patent applications including EP-A-711827 and EP-A-838519. A solubility of at least 50 grams per 100 grams of water at 20xc2x0 C. is an exceptionally high solubility: many materials which are classified so as water soluble are less soluble than this.
Some highly water-soluble materials which may be used are listed below, with their solubilities expressed so as grams of solid to form a saturated solution in 100 grams of water at 20xc2x0 C.:
By contrast the solubilities of some other common materials at 20xc2x0 C. are:
Preferably this highly water soluble material is incorporated so as particles of the material in a substantially pure form (i.e. each such particle contains over 95% by weight of the material). However, the said particles may contain material of such solubility in a mixture with other material, provided that material of the specified solubility provides at least 50% by weight of these particles, better at least 80%.
A particularly preferred material, sodium acetate trihydrate, is normally produced by a crystallisation process, so that the crystallised product contains 3 molecules of water of crystallisation for each sodium and acetate ion pair. Sodium acetate in an incompletely hydrated form, which may be produced by a spray-drying route, can also be used.
Another possibility is that the said particles which promote disintegration are particles containing sodium tripolyphosphate with more than 50% of it (by weight of the particles) in the anhydrous phase I form. Such particles may contain at least 80% by weight tripolyphosphate and possibly at least 95%. Detergent tablets containing such material are the subject of our EP-A-839906.
Sodium tripolyphosphate is very well known so as a sequestering builder in detergent compositions. It exists in a hydrated form and two crystalline anhydrous forms. These are the normal crystalline anhydrous form, known so as phase II which is the low temperature form, and phase I which is stable at high temperature. The conversion of phase II to phase I proceeds fairly rapidly on heating above the transition temperature, which is about 420xc2x0 C., but the reverse reaction is slow. Consequently phase I sodium tripolyphosphate is metastable at ambient temperature.
A process for the manufacture of particles containing a high proportion of the phase I form of sodium tripolyphosphate by spray drying below 420xc2x0 C. is given in U.S. Pat. No. 4,536,377.
Particles which contain this phase I form will often contain the phase I form of sodium tripolyphosphate so as at least 55% by weight of the tripolyphosphate in the particles. Other forms of sodium tripolyphosphate will usually be present to a lesser extent. Other salts may be included in the particles, although that is not preferred.
Desirably, this sodium tripolyphosphate is partially hydrated. The extent of hydration should be at least 1% by weight of the sodium tripolyphosphate in the particles. It may lie in a range from 2.5 to 4%, or it may be higher, e.g. up to 8%.
Suitable material is commercially available. Suppliers include Rhone-Poulenc, France and Albright and Wilson, UK.
xe2x80x9cRhodiaphos HPA 3.5xe2x80x9d from Rhone-Poulenc has been found particularly suitable. It is a characteristic of this grade of sodium tripolyphosphate that it hydrates very rapidly in a standard Olten test. We have found that it hydrates as quickly as anhydrous sodium tripolyphosphate, yet the prehydration appears to be beneficial in avoiding unwanted crystallisation of the hexahydrate when the material comes into contact with water at the time of use.
Other Ingredients
The detergent tablets of the invention may also contain a fluorescer (optical brightener), for example, Tinopal (Trade Mark) DMS or Tinopal CBS available from Ciba-Geigy AG, Basel, Switzerland. Tinopal DMS is disodium 4,4xe2x80x2bis-(2-morpholino-4-anilino-s-triazin-6-ylamino)stilbene disulphonate; and Tinopal CBS is disodium 2,2xe2x80x2-bis-(phenyl-styryl)disulphonate.
An antifoam material is advantageously included, especially if a detergent tablet is primarily intended for use in front-loading drum-type automatic washing machines. Antifoam materials in granular form are described in EP 266863A (Unilever). Such antifoam particles typically comprise a mixture of silicone oil, petroleum jelly, hydrophobic silica and alkyl phosphate so as antifoam active material, sorbed onto a porous absorbed water-soluble carbonate-based inorganic carrier material.
Further ingredients which can optionally be employed in fabric washing detergent tablet of the invention include anti-redeposition agents such as sodium carboxymethylcellulose, straight-chain polyvinyl pyrrolidone (which can also act as a binder, as mentioned earlier) and the cellulose ethers such as methyl cellulose and ethyl hydroxyethyl cellulose, heavy metal sequestrants such as EDTA; soil release polymers, fabric softening agents, other fabric conditioning agents, colorants or coloured speckles.
Particle Size and Distribution
The discrete regions of a detergent tablet of this invention, are each a matrix of compacted particles. Preferably the particulate mixture of particles, from which each tablet region is compacted, has an average particle size before compaction in the range from 200 to 2000 xcexcm, more preferably from 250 to 1400 xcexcm. Fine particles, smaller than 180 xcexcm or 200 xcexcm may be eliminated by sieving before tableting, if desired, although we have observed that this is not always essential.
While the starting particulate composition may in principle have any bulk density, the present invention is especially relevant to tablets made by compacting powders of relatively high bulk density, because of their greater tendency to exhibit disintegration and dispersion problems.
Such tablets have the advantage that, as compared with a tablet derived from a low bulk density powder, a given dose of composition can be presented as a smaller tablet.
Thus the starting particulate composition may suitably have a bulk density of at least 400 g/liter, preferably at least 550 g/liter, and perhaps at least 600 g/liter.
Granular detergent compositions of high bulk density prepared by granulation and densification in a high-speed mixer/granulator, as described and claimed in EP 340013A (Unilever), EP 352135A (Unilever), and EP 425277A (Unilever), or by the continuous granulation/densification processes described and claimed in EP 361339A (Unilever) and EP 390251A (Unilever), are inherently suitable for use in the present invention.
Porosity
The step of compacting the particles reduces the porosity of the composition. Porosity is conveniently expressed as the percentage of volume which is air.
The air content of a tablet or region of a tablet can be calculated from the volume and weight of the tablet or region, provided the air-free density of the solid content is known. The latter can be measured by compressing a sample of the material under vacuum with a very high applied force, then measuring the weight and volume of the resulting solid.
The percentage air content of a tablet or region of a tablet varies inversely with the pressure applied to compact the composition while the strength of the tablet or region varies with the pressure applied to bring about compaction. Thus the greater the compaction pressure, the stronger the tablet or region becomes but the smaller the air volume within.
The invention may be applied when compacting particulate detergent composition to give tablets with a wide range of porosities. Specifically included among possible porosities it a porosity of up to 38% air volume, e.g. from 10 or 15 better 25% up to 35% air by volume in the tablet.

Unilever Home and Personal Care USA division of Conopco, Inc.


In a safety device for a tank system with a tank pipe 1 which has a pliable region and a rigid region, a reinforcing element 7 is allocated to the rigid region of the tank pipe 1. The reinforcing element 7 is hollow and is in contact with the entire circumference of the tank pipe 1 with its interior contour.

This application claims the priority of German patent document 103 38 065.5, filed Aug. 19, 2004, the disclosure of which is expressly incorporated by reference herein.
The invention concerns a safety device for a tank system having a tank pipe.
German patent document DE 36 35 468 C2 discloses a tank pipe having one end that faces a filler neck and another end that faces a fuel container. The tank pipe has a pliable region which includes an internal rubber hose and a bellows-like outer hose, to compensate for deformation in the event of an accident. The bellows-like outer hose allows for a sufficient deformation path for this purpose, while the internal rubber hose serves for a good flow behavior when filling the tank. If the elasticity of the inner rubber hose is exceeded in the event of an accident, the rubber hose tears on a target breakage site. The tightness of the tank pipe remains guaranteed since the elasticity of the outer hose is designed for large deformation pathways.
A tank pipe disclosed in German patent document DE 36 35 469 A1 has a filler neck or a fuel container arranged on ends thereof. The tank pipe likewise has a pliable region including two corrugated pipes with different strength inserted one into the other, to compensate for deformations. The internal corrugated pipe has a lesser strength than the outer corrugated pipe. While the outer corrugated pipe enables a sufficient deformation path for the action of force in the event of an accident, the inner corrugated pipe detaches from the outer corrugated pipe in response to a specified force.
To summarize, the tank pipes known from the state of the art include a pliable region having two pipes lying one inside the other to compensate for deformations arising in the event of an accident.
One object of the present invention is to provide a tank pipe which offers enhanced safety for those involved in traffic in the event of a collision.
This and other objects and advantages are achieved by the safety device according to the invention, which consists of a hollow reinforcing element that is attached externally on the tank pipe. The reinforcing element conforms to the tank pipe so that it is in contact therewith over its entire circumference. (However, within the scope of the invention, it is also possible for the reinforcing element to be only partially in contact with the tank pipe.) The reinforcing element has a stiffening function.
Due to a separate mode of construction of tank pipe and reinforcing element, different materials can be used for the two components. This way the positive characteristics of the individual materials can be combined with each other. Furthermore the tank pipe can be used for different types of motor vehicles, and reinforced individually with the reinforcing element on the particularly endangered places for the respective type of motor vehicle. In the event of an accident, motor vehicle parts arranged in the vicinity of the tank pipe can come into contact with and damage to the tank pipe. Due to the special stiffening on the endangered region of the tank pipe, the tank pipe is protected from this type of damage.
In one embodiment, the reinforcing element has a basically circular cross section that is constant over its entire length. In this way, the reinforcing element and the tank pipe (which in this embodiment likewise has a constant circular cross section) are harmonized with each other, with the inside diameter of the reinforcing element corresponding to the outside of the tank pipe. The reinforcing element encloses the tank pipe like a second skin and in this way requires little space. Furthermore, the reinforcing element has a particularly stable construction due to the constant cross section in the longitudinal direction.
It is, however, also possible within the scope of the invention that the cross section of the reinforcing element is not constant over the its length, but is tapered, for example. In this way, the reinforcing element can be individually adapted to different tank pipes and the tank pipe can be freely configured. Likewise curvatures of the tank pipe can be taken into consideration in manufacturing the reinforcing element.
In order to install the reinforcing element simply and rapidly on the tank pipe, it consists of several separate components according to a further embodiment. Two sleeves can be provided as components, which are applied from the exterior to opposite sides of the tank pipe and thereby enclose it. The sleeves have a basically semicircular cross section. The longitudinal axis of the reinforcing element corresponds to the longitudinal axis of the tank pipe (which can be manufactured independently of the reinforcing element). Time is saved and costs can be reduced due to rapid installation. Providing three or four sleeves as reinforcing elements that are joined with one another during assembly is also possible. In this way, the reinforcing element can be adapted to the shape of the tank pipe.
The sleeves have recesses for accommodating fastening fixtures in accordance with a further embodiment. The installation is simplified in this way because the fastening points are already specified and fastening fixtures can simply be inserted into the receptacles.
In a further embodiment, the fastening fixtures are constructed in one piece with the tank pipe, for example, as elevations on the tank pipe. In this way, the reinforcing element can simply be clipped onto the tank pipe in one assembly step, and can also be released again. The elevations are constructed such that they snap into the recesses of the reinforcing element. The snap-fit can take place through a projection that is mounted on the elevation. This has the advantage that no additional fastening fixtures are needed for assembly, so that costs are saved. But other fastening possibilities of the sleeves are also possible, such as, for example, a gluing connection or a screwing connection.
The recesses are constructed trapezoid-like in a further embodiment.
In another embodiment, the boundary regions of the sleeves facing one another delimit a meandering separation line. For this purpose, the boundary regions of the sleeves have trapezoidal regions, and are harmonized with one another such that they engage into one another, but do not come into contact, following the installation of the tank pipe. In this way, they prevent sliding of the two sleeves toward one another in a longitudinal direction.
The fastening fixtures are constructed in one piece with one of the sleeves in a further embodiment, so that no additional fastening fixtures are needed, and costs as well as time are saved in installation. For example, the boundary regions of one of the sleeves can be bent outwardly as a fastening fixture. The sleeve has individual projecting boundary regions for this purpose that are bent toward the outside on their ends. These ends can be used as hooks or hinges for joining the two sleeves. This is a type of fastening fixture, which is simple to manufacture.
In accordance with a further embodiment, one of the sleeves has peripherally extending projections that have recesses for accommodating fastening fixtures. That is, the projections are tongue-like boundary regions of the sleeves, with recesses that are parallel to the longitudinal axis of the sleeve. The recesses can, for example, be constructed as oblong holes so that the bent boundary regions of the other sleeve can hook into the recesses, providing a simple detachable connection. The recesses may, of course, have other shapes, such as, for example, circular or rectangular. The fastening fixtures that are to be accommodated into the recesses are correspondingly adapted.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.


A method of sealing body parts such as an edge fold of a motor vehicle component, for example a door, a rear or front flap or a sliding roof panel, includes a two-step pre-cross-linking of the sealing composition in the rough body part. In a first step the surface of a UV-active sealing composition is pre-cross-linked by UV irradiation, and in a second step immediately following, the edge fold adhesive and the sealing composition are hardened by thermal action. The edge-sealed body parts produced by the method are transportable and are of visually and functionally satisfactory quality after passing through cleaning baths and after thermal hardening in a KTL kiln. Since the sealing is carried out in the rough body part rather than during the coating process, the method provides a substantial potential cost saving.

This invention relates to methods of edge fold sealing at the edges of body parts.
For edge fold sealing in motor vehicle construction, a hardenable material is commonly laid over the outwardly open part of the fold, usually in the form of a bead. The hardenable material is gelled in a first hardening operation, for example by inductive heating of the sheet metal in the region of the hardenable composition, and is then completely cured in a following hardening operation, which may take place, for example, in a KTL, i.e., xe2x80x9ccathodic dip coatingxe2x80x9d) kiln. As the hardenable composition, polyvinyl chloride (PVC) is often employed.
This method presents problems when the hardenable material encloses pockets of air or absorbs liquids or gases before final hardening that will expand during subsequent kiln hardening and form outwardly visible blisters. These blisters in the first place impair the visual appearance of the sealed edge and in the second place form weak spots permitting corrosive attack in the seal.
In an alternative conventional finishing step in the production of vehicle parts, for example doors, hatch and hood flaps, sliding roof panels and the like, two sheet metal parts are connected by folding the edge of an outer part over the edge of an inner part. Thus, in building the unfinished rough body part, an adhesive is first applied to the oiled metal sheet, generally consisting of steel, hot-galvanized or electrically galvanized steel or aluminum, along the edge of the outer part, generally by xe2x80x9cswirlxe2x80x9d processes in a layer having a thickness of about 0.2 mm and, after insertion of the inner part, the outer edge of the outer part is rolled over the periphery of the inner part. Only then is the corrosion-sensitive edge of the outer part sealed by coating, usually by hand, with a sealant such as PVC plastisols for example. For reasons of production technology, quality and economy, it would be desirable to eliminate such edge fold sealing from the coating process and relegate it to construction of the rough body part, i.e. to employ the first method described above. In other words, there should be no material applications in the coating process that might impair the coating surface in any way. Hitherto, this objective has not been satisfactorily achieved, since as yet no dependable and economical procedure is available for the purpose.
German Offenlegungsschift No. 33 14 896 describes an adhesive for edge fold sealing that is pre-cross-linked by ultraviolet (UV) irradiation and is later finish-hardened in the kiln after passing through the cleaning baths at temperatures of around 180xc2x0 C. together with the KTL priming. Apart from the relative simplicity of UV irradiation, it also has the disadvantage that the resulting hardening, and hence the cross-linking as well, takes place only from the outside in. For layer thicknesses greater than 0.3 mm, adequate pre-cross-linking can not be assured even with increased irradiation time, and the underlying layers remain un-cross-linked in a pasty condition. This pasty layer, beneath the pre-cross-linked surface has significant negative effects on the visual appearance of the seal. First, since the parts are at times transported manually, one consequence is that the adhesive, while not tacky, is not solid, resulting in fingerprints which may constitute a visual drawback. Second, there is danger that this uncross-linked material may be forced out of the seal upon thermal hardening in the KTL kiln as a result of expansion of the air enclosed between the edge fold bond and the seal. Third, upon subsequent cooling, the pasty seal material may be drawn back in the edge fold. Fourth, adhesives tend, especially in un-cross-linked condition, to absorb moisture, leading to formation of blisters upon thermal exposure in the KTL kiln.
The conditions described above are significant in the sense that it is desirable for reasons of economy to produce the parts in a finished form, that is, including the seal, at a central station and ship them from the central station to production lines which may be located in different parts of the world where they go directly into the cleaning bath which is the first step in the coating process. This procedure involves a substantial potential saving since the rough body parts and the sealing steps, which are in any event unwelcome in the coating process, can be avoided on the production line. Moreover, any new sealing process should be capable of integration in existing finishing operations on the rough body parts satisfactorily and without major financial outlay. In this respect, the requirement for an additional kiln would be absolutely unacceptable.
Accordingly, it is an object of the present invention to provide a method of edge fold sealing which overcomes disadvantages of the prior art.
Another object of the invention is to provide a method of edge fold sealing in which blister formation due to enclosed gases or liquids is suppressed in the subsequent kiln treatment, and/or good xe2x80x9chandlingxe2x80x9d of the sealed parts is assured throughout process.
These and other objects of the invention are attained by providing a method of edge fold sealing which includes pre-hardening of a seal in a plurality of steps which may include ultraviolet radiation hardening and/or thermal hardening by infrared radiation, inductive heating and hot air impingement and/or reactive hardening without any external application of energy.
In accordance with the invention, a special process for the production of vehicle components, and particularly a new method of edge fold sealing, is provided in which fabrication is greatly simplified and quality enhanced.
Thus, by the method of the present invention, the disadvantages of the prior art are overcome, and edge fold sealing is carried out that satisfies all requirements for secure production of attachments and, in particular, for worldwide transport of xe2x80x9croughxe2x80x9d or oiled parts, otherwise known as xe2x80x9cparts tourism.xe2x80x9d In such cases, it is important for the visual quality of the edge fold seal to remain perfect even after prolonged transport of the parts through various climate zones and to ensure a smooth surface without pits, cracks, etc. Furthermore, the method may be applied to the rough body parts without any major fixed investment, and substantial manufacturing advantages can be gained by the new method.
According to a preferred embodiment of the invention, hardening of the seal takes place by a photochemical reaction, induced by light, in particular UV light, combined with a multi-step hardening procedure. Depending on the kind of seal, the UV light has a depth of penetration from about 0.01 to 1 mm, so that a surface hardening of the seal is achieved but deeper penetration of the UV radiation is also possible. The seal surface thus hardened protects against the entry of gases or liquids into the seal so that, upon later thermal hardening, no blisters will be raised. In addition, with such a surface hardening, emergence of any gases already contained in the seal is suppressed or prevented during thermal hardening.
Advantageously, the photochemical hardening is accomplished in such manner that, upon subsequent thermal hardening, the region of the composition that has already been photochemically hardened will be further hardened by the thermal hardening, i.e. so that functional groups which are already present for the photochemical as well as the thermal hardening will also be thermally cross-linked to enhance the hardening. In this way, an especially stable surface of the sealing composition is created.
For all embodiments of the method, a sealing procedure may be employed in which hardening is an exothermal process, so that once initiated, the hardening process continues at least in part, and correspondingly a more complete hardening is achieved. For this purpose, the sealing may combine reactive sealing components so as to be capable of initiating the hardening process without application of external energy.
In a further embodiment according to the invention, at least two unlike hardening processes are carried out prior to coating of the sealed body part. Preferably one of the hardening processes effects hardening of the outer surface of the seal and the other hardening process hardens the region of contact of the seal with the body part. In this way the method assures that the seal will absorb no liquid during the coating process, in particular liquid from a liquid cleaning preceding coating such as an aqueous solution and/or an aqueous immersion coating that would lead to blister formation upon subsequent thermal hardening, for example, in a KTL kiln.
In another embodiment, the thermal hardening, at least in a first stage, is kiln-free or accomplished by only partial heating of the body parts that are provided with the seal. In this way, a favorable overall procedure is achieved in that a hardening sufficient to prevent subsequent blister formation is integrated in the process as a whole without major outlay.
In still another embodiment of the invention, the process is carried out so that the two unlike hardening processes are conducted in succession at a time interval of less than 2 hours. In this way, a sufficient hardening of the seal is achieved without permitting it to absorb any significant quantity of gases or liquids that might lead to the problems outlined above. A time interval of less than 1 hour, preferably less than 20 minutes, desirably less than 5 minutes, is advantageous. That is, the two hardening processes preferably take place simultaneously or in immediate succession, without any additional interposed steps.
According to the invention, the alternative embodiments may advantageously be combined with each other.
The method of the invention is based on at least two-step cross-linking of the edge fold seal. Thus in a first step, a UV-active sealing composition is hardened by UV irradiation and, in a second directly following step, advantageously both the edge fold adhesive and the seal are cross-linked from the inside by thermal heating.
The hardening from the outside by UV irradiation partially cross-links the edge fold seal, effecting firstly a graspability or solidity of the seal surface important for manual handling, secondly a wash-out resistance to the liquids circulating against it at up to 70xc2x0 C. under high pressure in the cleaning baths for degreasing the oiled bodywork, phosphating, and passing through the cathodic dip coating bath (KTL), and thirdly, due to the further cross-linking in a second hardening process, assures seal quality for a long exposure time, partly under hot-moist climatic conditions for more than 3 weeks. Exposure time specifies the time within which the adhesive performs the specified function and suffers no quality drawbacks after complete hardening in the KTL kiln, which takes place at temperatures around 180xc2x0 within about 25 minutes. In a less than 100% cross-linked condition, the adhesive generally tends to absorb water, leading to blister formation upon heat hardening and possibly adversely affecting both appearance and strength.
For the hardening process producing adhesive cross-linking under UV radiation, activated double bonds, as for example compounds containing acrylate groups, the radical polymer reaction is triggered by way of a photoinitiator which is a radical former initiated by UV rays. Depending on the particular photoinitiator, the optimal wavelength is in the range from 200 to 400 mm. To achieve a satisfactory result in terms of solidity, etc., an irradiation time of less than 30 seconds, preferably less than 5 seconds, at an intensity of preferably 0.001 to 50 watts/cm2, is suitable. This makes possible a procedure in which, for example, the UV irradiation can be carried out by robots directly after application of the seal and in the same operation. The UV lamp is advantageously located directly following the nozzle applying the sealing material.
The thermal hardening from within partially cross-links the edge fold bond and the seal and effects a positional stability, precluding relative displacement of the two sheet-metal parts, i.e. inner part and the outer part. As sources of thermal energy, induction heating, infrared (IR) irradiation, hot air blasts, etc. are useful. In the case of IR irradiation, although the costly fixed investment for an induction plant may be avoided, it is not as effective as inductive heating.
As a result of the invention it was found that a two-stage hardening process is adequate to assure sufficient positional stability of the parts being attached even without complete hardening since the outer seal part hardened with UV radiation also contributes to structural strength. If desired, the IR lamps may be positioned on the robot to irradiate the seal directly after UV irradiation. For satisfactory quality of the sealing surface, it is preferable that the UV irradiation takes place prior to the thermal exposure. This assures that any air contained between the edge fold bond and the seal will be kept inside during thermal heating.
Furthermore, in another preferred embodiment, the reaction induced by UV irradiation is accelerated by heating the sealing composition, for example, to temperatures around 60xc2x0 C. This may be done by heating the sealing composition itself before or as it is applied and/or heating the edge fold shortly before applying the sealing composition, for example, by a hot air blast and/or inductive heating, in order thereby to pre-heat the applied sealing composition.
Preferably, heating by IR and/or a hot air blast is employed. This definitely reduces or eliminates the danger of warping of parts since the parts are less severely stressed thermally than is the case in inductive heating for example.
Visual imperfections resulting from air inclusion in the edging between bonding and sealing are greatly reduced since the adhesive with twofold pre-hardening builds up sufficiently high strength in a short time and thus prevents both air inclusions upon heating in the KTL kiln as well as withdrawal of adhesive material into the edging upon cooling.
Since the sealing can be done more economically and with savings of material by the use of robots during rough fabrication rather than in a coating shop by hand as is conventional, resources such as time and space in the coating shop can be saved.
The method according to the invention provides advantages in properties such as good handling and positional stability as well as good exposure time, thus meeting all requirements for secure transport both internally and externally, and it overcomes the disadvantages of the prior art methods in which quality is impaired by blister formation. The advantages according to the invention permit fabrication of parts having edge seals, as for example doors, front and rear flaps, sliding roof panels, etc., at a central location and shipment of the parts to outside production lines. This xe2x80x9cparts tourismxe2x80x9d is otherwise known as CKD (xe2x80x9ccompletely knocked downxe2x80x9d) and is economical because fixed investment for the production of rough bodywork can be reduced.
For optimal processing the edge fold adhesive should be applicable in thin layers and exhibit good oil wetting. After heat hardening in the KTL kiln, the adhesive should provide a good, aging resistant adhesion to the metal substrate, a strength of more than 15 Mps and an ultimate elongation of at least 5%.
For the seal, the same adhesive used in the edge fold may be employed, in which case it will contain hardenable components that, in the most preferred embodiments, may be hardened either by UV irradiation or thermally. In that case the ultimate elongation should be at least 15%, preferably 30%, to avoid any risk of cracking under the thermal stresses.
The adhesives described above are generally formulated on the basis of epoxide technology, rubber technology or acrylate technology. etc., and also in combination with suitable polyurethane components or organic polymer fillers. Some examples are given in German Offenlegungsschrift No 33 14 896, to which reference is made also with respect to the conditions of reaction. The seal is preferably applied in a thickness of 150-4000 microns, desirably in the range of 350-1000 microns. Preferably the seal is applied in the form of a bead, the application of the bead being carried out for example as a xe2x80x9cswirl.xe2x80x9d
A light-induced hardening, in particular by irradiation with UV light, may advantageously take place immediately after application of the seal, preferably not later than a few minutes after application. The UV irradiation may take place at the same time as, previous to, or after a further hardening, in particular an IR, hot air stream or induction hardening, in which the sheet metal areas to be sealed and/or immediately adjacent areas may be heated.
Depending on the particular sealant employed, care should be taken, especially in case of insufficient exothermal hardening, to avoid a hardening which may possibly fail if the hardening process is not carried out with sufficient intensity. To assure success of the hardening process, it is accordingly necessary to work with a sufficient intensity of the hardening parameters (UV light, heat, etc.) to assume adequate hardening.
Advantageously, the sealing is carried out with a material for which the minimum hardening temperature is adjusted to not over 140xc2x0 C., for example, so that an induction hardening is possible. The epoxide resins commonly employed, which require a hardening temperature of about 150xc2x0 C. up to 170xc2x0 C., are therefore less suitable. However, such epoxides may be employed in the interior of the fold, since the final hardening in the KTL kiln does not present that problem.


A computing device determines one or more first degree correlations based on valuation information. The computing device determines one or more important variables based on at least a comparison between the absolute value of the one or more first degree correlations to a first threshold value. The computing device determines a valuation function based on at least one or more of the determined one or more important variables.

Machine learning is a branch of artificial intelligence that concerns the construction and study of systems that can learn from data. Many machine learning problems involve inferring a function from random labeled examples. For example, a machine learning system could be trained on email messages to learn to distinguish between spam and non-spam messages. After learning, it can then be used to classify new email messages into spam and non-spam folders. A focus of machine learning pertains to the concepts of representation and generalization. Representation of data instances and functions evaluated on these instances are part of all machine learning systems. Generalization is the property that the system will perform well on unknown data instances; the conditions under which this can be guaranteed are a key object of study in the subfield of computational learning theory. There are a wide variety of machine learning tasks and applications. For example, optical character recognition, in which printed characters are recognized automatically based on previous examples, is a classic example of machine learning.

Machine learning customer valuation functions

International Business Machines Corporation


A central solar receiver comprises an axisymmetric housing having front and rear ends and having an aperture at the front end, an elongated tubular window mounted in the aperture co-axially with the housing, a volumetric solar absorber disposed within the housing and extending around and along the elongated window for absorbing solar radiation that has passed therethrough; and working fluid ingress and egress formed in the housing so as to, respectively, inject thereto, and withdraw therefrom, a pressurized working fluid in a manner enabling the working fluid interaction with the volumetric absorber. The window has an open front end which is secured to the housing at the front end thereof, and a closed rear end which is disposed adjacent the rear end of the housing and is free of any securing thereto.

This invention relates to a central solar receiver, and, particularly, to a window for use in such a receiver for admitting and passing thereto concentrated solar radiation.
The present invention is particularly directed to a central solar receiver which comprises a housing with a solar absorber adapted to absorb concentrated solar radiation at high temperatures, commonlyxe2x80x94above 500xc2x0 C., and a working fluid circulating therein in indirect or direct heat exchange relationship with the solar absorber. The housing of such a solar receiver is formed with an aperture located in the focal region of a solar radiation concentration system, and holding a window adapted to admit highly concentrated solar radiation from the concentration system and to pass it towards the solar absorber.
The solar absorber used in central solar receivers of the above kind is often a volumetric solar absorber that is fabricated in the form of a three-dimensional matrix enabling the working fluid to flow therethrough, thereby transferring the heat to the working fluid. Such solar receivers are described, for example, in IL 97091 and U.S. Pat. No. 5,323,764.
The working fluid used in central solar absorbers normally either serves as heat carrier fluid or else is designed to perform a heat induced, possibly catalyzed, endothermic chemical reaction between components of the working fluid.
For various industrial applications such as the operation of gas turbines for electricity generation or the performance of endothermic reactions of the kind specified, it is necessary to enable the working fluid to circulate through the system at an elevated pressure of at least about 2 atmospheres. At such a pressure, the density of the circulating gaseous working fluid is higher than it would have been if it were in the non-pressurized state and, consequently, pressure losses during circulation are lower.
One of the most critical problems associated with a pressurized central solar receiver having a window, is the mechanical strength of the window. Materials that have required optical and thermal properties, tend to be brittle, which means that while they can withstand large compression stresses, they tend to crack or shatter under even relatively small tension stresses. Stresses in the window are created by the gas pressure in the interior of the receiver and also by uneven thermal expansion of the window and other receiver components that are in contact therewith, as they heat up during operation.
U.S. Pat. No. 5,323,764 and U.S. Pat. No. 5,421,322 disclose a central solar receiver with a window having a frusto-conical shape having a front large-diameter and rear small-diameter open ends both formed with cylindrical front and rear rims at which the window is secured to the housing at its front and rear ends. The front end of the housing is formed with an annular positioning groove and the front rim of the window is received therewithin and secured there by means of an O-ring. The rear rim of the window is secured within a metal block which inter alia includes thermal expansion absorbing bellows and a reflector adapted to protect the block and also the bellows from concentrated solar radiation entering the window.
It is an object of the present invention to provide a new window for use in a central solar receiver and a new central solar receiver using the same.
According to one aspect of the present invention, there is provided a central solar receiver comprising:
an axisymmetric housing having front and rear ends and having an aperture at the front end;
an elongated tubular window mounted in said aperture co-axially with the housing, the window having an open front end which is secured to the said housing at the front end thereof, and a closed rear end which is disposed adjacent the rear end of the housing and is free of any securing thereto, the window having a first surface facing incident concentrated solar radiation and a second surface facing the interior of the housing;
a volumetric solar absorber disposed within said housing and extending around and along said elongated window for absorbing solar radiation that has passed therethrough; and
working fluid ingress and egress formed in said housing so as to, respectively, inject thereto, and withdraw therefrom, a pressurized working fluid in a manner enabling the working fluid interaction with said volumetric absorber.
In accordance with another aspect of the present invention, there is provided a window for use in a central solar receiver of the above kind, for admitting and passing into the receiver incident highly concentrated solar radiation, the window having an elongated tubular shape with an open front end adapted for being secured in said aperture of the receiver, and a closed rear end free of any securing means.
The design of the window of the present invention and the manner of its mounting in the central solar receiver, whereby the window is secured only at its front end, simplify the receiver""s design and prevent the window from having undue constraints, which renders it suitable for use at high temperatures and elevated pressures.
The window is preferably of a frusto-conical shape, with its open front end being a large diameter end and its closed rear end being a small diameter end. However, the window may have any other elongated axisymmetric shape, e.g. a cylindrical shape, in which case its front end may be formed with a rim having a diameter greater than that of the remainder of the window.
Preferably, the window""s front end is secured to the housing by elastic mounting devices such as, e.g. spring-loaded clamps, that permanently exert on the window""s body axial force that keeps the window in place and prevents its motion under forces acting thereon during thermal and pressure cycles when the receiver is operated.
Preferably, the rear closed small-diameter end of the window is in the form of a cap-like concave surface continuously merging with the window""s conical surface. This shape of the closed end, and the frusto-conical shape of the window""s body, ensure that any pressure exerted on the window from within the housing produces force components acting perpendicular and along the window""s surface, which only results in compression stresses rather than tension stresses that may cause the window to crack.
Preferably, the working fluid ingress is located adjacent the rear end of the housing co-axially therewith so as to face said closed end of the window. It is still more preferable that an additional solar absorber is mounted in the housing between the working fluid ingress and the closed end of the window so as to absorb concentrated solar radiation that has passed through the closed end. Thereby, the working fluid ingress is protected from direct penetration thereto of concentrated solar radiation and is pre-heated, while entering the receiver, before its interaction with said volumetric solar absorber. The additional solar absorber may also be a volumetric solar absorber.


The invention provides compositions, kits and methods for depositing a composition comprising a plurality of magnetic particles, to a target site of a subject by delivering the composition via controlled inhalation to a region of the subject's respiratory tract and applying a magnetic field to a target site within the region of the subject's respiratory tract to capture the particles in said target site.

The lungs can be described as a dense tree, where the airways resemble branches, ending with raspberry-like acinar sacs. The acinar sacs are made of alveoli, the basic respiratory units of the lungs. The alveolar lumen is composed of a confluent layer of alveolar epithelial cells where the underlying alveolar wall membrane is perfused by a vast network of capillaries (FIG. 1B). The main function of the lungs is undertaken within the alveolar space with the exchange of oxygen and carbon dioxide.
The lungs constitute the largest non-invasive pathway for drug delivery, with an exchange surface estimated at over 100 m2 in an average adult. This pathway is particularly attractive for treating lung diseases topically, including lung cancer, asthma and obstructive diseases (e.g., COPD). Moreover, from a systemic delivery perspective, it can represent the only available non-invasive delivery method for many drugs that cannot be orally administered through the digestive system due to degradation (e.g., proteins such as insulin).
In past decades, there has been substantial progress in understanding respiratory fluid dynamics and the transport of inhaled therapeutic aerosols, including the physical (e.g., aerodynamic) determinants affecting lung deposition outcomes. Nevertheless, the ability to target either a specific pulmonary region (e.g., alveolar region) or a localized point within the airway tree (e.g., lung tumors in the context of bronchogenic carcinoma) remains poor.

Targeted delivery of aerosols of magnetized active agents

TECHNION RESEARCH & DEVELOPMENT FOUNDATION LIMITED


An adjustable helmet, particularly a cyclist""s helmet having at least one longitudinal spar which is intended to be positioned above the parting, two end pieces one of which is intended to be positioned above the forehead and the other one above the back of the head. Guides between the end pieces and the longitudinal spar which are aligned approximately in parallel with the parting. Two lateral elements which are intended to be positioned above the temples, guides between the end pieces and the lateral elements which are aligned obliquely to the parting, and an adjusting and/or locating device for the relative position of the longitudinal spar, end pieces, and lateral elements.

Not Applicable
Not Applicable
The invention relates to an adjustable helmet, particularly a cyclist""s helmet.
Helmets are headpieces made of plastic or metal which are intended to protect the user from detrimental or injury-causing influences. Thus, driver""s helmets serve for shock absorption during a fall, worker""s helmets protect from objects that fall down, and fireman""s helmets which additionally have a vapour-deposited outer surface protect from the effects of heat. Helmets are also used in various sports as a protection against falls, sports equipment or objects that fall down, particularly in cycling, inline skating, riding, ice hockey or mountain climbing.
In many cases, helmets consist of a resistive outer shell which, for being worn, may be fixed at some points to an insert which is adjustable or, in part, is even removable and has a crossed rib. Many helmets have an outer shell with a cushioning lining in moulded plastic foam, particularly as a protection from shocks. Such helmets are used in cycling, in particular. However, there are also helmets which are integrally pressed from solid plastic foam and are worn with no specific inserts and with or without a padding. An adjustable chin strap allows them to be safely worn in most designs.
The known helmets which are lined with plastic foam or are integrally pressed from solid plastic foam generally are accommodated to a certain head size. However, such helmets also exist with an inner ring or a retaining plate which allow them to be adjustably supported on the circumference of the head to allow accommodation to different head sizes. Such systems may be adjustable, in particular, via Velcro closures or adjusting rings. These possible adjustments, however, involve losses to safety because the head is not directly supported via cushioning members in the shell, at least in some areas.
In addition, helmets are known already with exchangeable plastic foam paddings which allow them to be accommodated to various head shapes. However, such systems cause great expenditure and are restricted in variability.
Therefore, it is the object of the invention to provide a helmet of an improved adjustability with no loss to safety and with no need to exchange accommodating elements.
An adjustable helmet, particularly a cyclist""s helmet, according to the invention has
at least one longitudinal spar which is intended to be positioned above the parting,
two end pieces one of which is intended to be positioned above the forehead and the other one above the back of the head,
guides between the end pieces and the longitudinal spar which are aligned approximately in parallel with the parting,
two lateral elements which are intended to be positioned above the temples,
guides between the end pieces and the lateral elements which are aligned obliquely to the parting, and
an adjusting and/or locating device for the relative position of the longitudinal spar, end pieces, and lateral elements.
This helmet provides adjustability in the longitudinal direction and cross direction by the fact that the longitudinal spar and the end pieces are adapted to be displaced with respect to each other along the guide aligned approximately in parallel with the parting, and that end pieces and lateral elements are adapted to be displaced relative to each other along the guides directed obliquely to the parting. Since the displacement of the end pieces also implies the one of the lateral elements the adjustment of the length and width of the helmet is simultaneous. The adjusting and/or locating devices, in particular, may be such as locate the longitudinal spar, end pieces, and lateral elements in a relative position which is achieved by manually acting on those elements. Thus, the devices may specifically be clamping devices which locate the end pieces on at least one of the guides. However, the devices may also be devices which when actuated cause a change to the relative position of the aforementioned elements to each other. Those can be designed so as to be capable, in addition, of maintaining the elements in an adjusted position.
Thus, the inventive helmet allows to make changes to both the longitudinal and transverse dimensions of a helmet in an extremely simple manner. The components the relative position of which is changed here may be cushioning elements which are made from a plastic foam, for example, so that no losses to safety will occur. Moreover, it is unnecessary to exchange components for an adjustment to different head sizes.
According to an advantageous aspect, the helmet may have two longitudinal spars which are approximately parallel. Each of these parallel longitudinal spars may be guided with respect to the end pieces by means of guides aligned approximately in parallel with the parting. Preferably, the parallel longitudinal spars may be connected to each other by cross webs in order to form a particularly stable helmet component which can be arranged above the parting.
The end pieces may have longitudinal-spar end portions which are flush with the at least one longitudinal spar and which are engaged by the guides aligned approximately in parallel with the parting. This helps achieve a continuation of the stabilizing, weight-saving, and air permeable spar structure up to the inside of the end portions.
According to another aspect, the lateral elements also are designed as curved spars. The end pieces further may be designed with legs aligned in a U shape and/or V shape which are engaged by the guides aligned obliquely to the parting.
If the aforementioned aspects are combined with each other the helmet will be of a structure comprising longitudinal spars overlapping the partings and lateral spars overlapping the temples with all of the spars being converged at the ends above the back of the head and the forehead in end piece material accumulations which provide a particularly good protection.
According to another aspect, guides directed transversely to the parting are arranged between the at least one longitudinal spar and the lateral elements, which stabilize the helmet in a cross direction and prevent a relative displacement of the longitudinal spar and the lateral elements in a longitudinal direction.
The guides directed in parallel with and/or obliquely to and/or transversely to the parting may have straight-lined guide bodies which engage complementary pockets of the longitudinal spar and/or the end pieces and/or the lateral elements. Then, the guides may be completely integrated in the cross-sections of the various components so as not to form interfering components or components that are even apt to cause injuries.
If was mentioned already the adjusting and/or locating device may solely serve for fixing the elements in their manually adjusted relative position. Instead, however, it may be a device which allows to adjust the relative position. In addition, the setting device may have self-locking properties such that it also is a device for locating the elements in the relative position chosen.
The adjusting and/or locating device may be designed in different ways. In a particularly advantageous aspect, this device has at least one setting screw which engages at least two of the elements adapted to be displaced relative to each other in order to change their relative position by rotating the setting screw by means of an actuating member which is connected thereto. The guides between the displaceable elements ensure that the elements which are not engaged by the setting screw are appropriately displaced. Moreover, the setting screw may fix the elements in the relative position adjusted by means of a threadable, self-locking engagement with these.
It is particularly advantageous if the setting screw extends across three adjacent elements the relative position of which needs a displacement, and engages at least the two outer ones of these elements because a uniform displacement of all elements and a particularly firm coherence thereof may then be realized in their adjusted position. To this end, the setting screw particularly may extend through the longitudinal spar and into the two end pieces so as to cause their displacement directly and the displacement of the lateral elements indirectly via guides.
Generally, however, it is also possible for the setting screw to extend through the longitudinal spar and into the two end pieces in a cross direction in order to displace the lateral elements directly and the end pieces indirectly via guides. Further, the setting screw may also extend into two end pieces through a lateral element or into two lateral elements through one end piece.
According to an advantageous aspect, the setting screw is designed to be flexible so that it may follow a bulging of the elements being adjusted that these have for an adaptation to the general shape of a human""s head. This also helps achieve that the screw is surrounded by cushioning material at any point, which farther improves safety. On the other hand, this favours an accommodation of the elements being adjusted to the shape of the head and their thin-walled design. It is preferred that the setting screw be designed flexible if it extends across elements that need an adjustment.
The setting screw engages at least one of the elements to be adjusted by being in a threadable engagement with those. Basically, it may be in a threadable engagement with all elements through which or into which it extends. Oppositely directed threads or threads having different pitches can ensure that the elements are displaceable towards each other or away from each other by rotating the setting screw. It is not definitely necessary for the screw to engage the longitudinal spar. Rather, its position may be clearly defined by guides which are parallel or directed transversely to the parting.
According to an advantageous aspect, the setting screw has an axial support on one of the elements so that when actuated it will not be displaced with respect to this element. This favours a stationary mounting of an actuating member.
According to a further aspect, there are two setting screws which are symmetrically arranged. This promotes an axial alignment, a setting, and a safe location of the elements. For example, the setting screws may be guided into the two end pieces through longitudinal spars which are substantially parallel. However, they also may extend into the two end pieces through the two lateral elements. In addition, it naturally is also possible for the two setting screws to extend into the lateral elements through the two end pieces.
Two setting screws may be adjustable by means of a separate or common actuating member which acts on the two setting screws via a gear set. The gear set may specifically be a wheel gear set. In particular, it may be a spur gear set, a bevel gear set or a worm gear set, depending on how the setting screws and the actuating member are aligned towards each other.
On a principle, however, the adjusting and/or locating device can be designed in another way. For example, it may have two toothed racks the ends facing away from each other are connected to various elements that need an adjustment (e.g. the end pieces) and, in an overlapping area, mesh with a gear which is supported on a further element (e.g. the longitudinal spar) and can be adjusted by means of an actuating member. The actuating member may be arranged on the same element as is the gear, or on another, in which case it is connected to the gear via a shaft. The toothed racks and, if necessary, the shaft may be designed to be flexible.
Preferably, the actuating member is designed as an adjusting gear.
The elements being adjusted which are intended to be positioned on the head of the wearer directly or via a padding on the inside may be made, completely or in part, of a cushioning material. Specifically, they may be made of a plastic foam.
The adjusting and/or locating devices may be made, completely or in part, of a plastic material.
The material which also is particularly suited for use in guide bodies of the guides is plastic or metal.
Generally, it is possible for the elements being adjusted to define the outer surface of the helmet. Furthermore, the helmet may have a shell at its outside. This can be fixed, in particular, only to one of the elements that need an adjustment. However, the shell can also be defined by portions that imbricatedly overlap each other and are fixed only to one of the elements each.


A MEMS-based display device is described, wherein an array of interferometric modulators are configured to reflect light through a transparent substrate. The transparent substrate is sealed to a backplate and the backplate may contain electronic circuitry fabricated on the backplane. The electronic circuitry is placed in electrical communication with the array of interferometric modulators and is configured to control the state of the array of interferometric modulators.

1. Field of the Invention
The field of the invention relates to microelectromechanical systems (MEMS). More specifically, the field of the invention relates to interferometric modulator based displays.
2. Description of the Related Technology
Display devices such as LCDs generally require electronic controlling circuitry located exterior to a protective package surrounding the display element. For example, an LCD comprises two sheets of glass surrounding a liquid crystal element. Controlling an LCD typically requires circuitry external to the package formed by the two sheets of glass. Positioning such controlling circuitry exterior to this protective package necessarily increases either the footprint or the height of the device.
Other types of displays are based on microelectromechanical systems (MEMS). These MEMS can include micro mechanical elements, actuators, and electronics. Micromechanical elements may be created using deposition, etching, and or other micromachining processes that etch away parts of substrates and/or deposited material layers or that add layers to form electrical and electromechanical devices. One type of MEMS device is called an interferometric modulator. An interferometric modulator may comprise a pair of conductive plates, one or both of which may be transparent and/or reflective in whole or part and capable of relative motion upon application of an appropriate electrical signal. One plate may comprise a stationary layer deposited on a substrate, the other plate may comprise a metallic membrane separated from the stationary layer by an air gap. Such devices have a wide range of applications, and it would be beneficial in the art to utilize and/or modify the characteristics of these types of devices so that their features can be exploited in improving existing products and creating new products that have not yet been developed.

Method and device for providing electronic circuitry on a backplate


A voltage level translator circuit has a digital logic circuit having a digital logic signal, at least one high-voltage capacitor having a first and second connection, wherein one of the first and second connections is electrically coupled to the digital logic signal, and a cross-coupled inverter pair having, the output of at least one inverter of the pair electrically coupled to the other connection of the at least one high-voltage capacitor. A high-voltage driving circuit has two low-voltage input signals, two high-voltage output signals, a first signal being a high-side drive signal and a second signal being a low-side drive signal, two level translators, a first level translator corresponding to the high-side drive signal, and a second level translator corresponding to the low-side drive signal, the level translators including a digital logic circuit having a digital logic signal, at least one high-voltage capacitor having a first and second connection, wherein one of the first and second connections is electrically coupled to the digital logic signal, and a cross-coupled inverter pair having, the output of at least one inverter of the pair electrically coupled to the other connection of the at least one high-voltage capacitor.

Many types of imaging systems, such as flat panel displays and non-thermal, direct marking print heads require bi-directional drive of many high voltage elements. These imaging systems typically have arrays of imaging elements that form images on displays or on print surfaces by selective turning on and off the imaging elements. High-voltage output transistors generally control the on or off state of the elements by selectively connecting them to either a positive or a negative high voltage supply rail, or to neither.
Generally, low-voltage signals, relative to the driving signals for the imaging elements, control the timing and state of the drive signals. Display and print head driving controllers, or chips, receive relatively low-voltage serial digital bit streams of image data and convert them to parallel data of 96 to 640 bits wide. The driver chips then translate the levels of the low-voltage signals to track the high voltage supply rails and use those level-translated signals to switch high-voltage output transistors that control the on and off state of the imaging elements.
The terms 'low-voltage' and 'high-voltage' used here relate to each other. A 'low-voltage' signal is one used to drive the logic circuitry, generally between 2.5 and 5 V. A 'high-voltage' signal is one that is higher than the voltage used to drive the logic circuitry, such as signals between 10 and 100 V.
Existing driver chips use high-voltage transistors in DC coupled configurations to accomplish this level translation. These high-voltage transistors typically require large isolation areas around each transistor, therefore requiring large areas of the chip substrate such as silicon, increasing the cost of the chip.
One solution lies in the use of capacitively coupled level translation that requires less area and therefore enables lower cost chips. However, existing capacitively coupled isolation circuits generally take up too much area and are too complex to fits hundreds of copies on a single chip.

Low-voltage to high-voltage level translation using capacitive coupling