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Publication numberUS20050087213 A1
Publication typeApplication
Application numberUS 10/468,669
Publication dateApr 28, 2005
Filing dateFeb 18, 2002
Priority dateFeb 22, 2001
Also published asCA2438869A1, CA2438869C, DE60202369D1, DE60202369T2, EP1404623A2, EP1404623B1, US7361632, US7456142, US7939483, US20050253116, US20080015101, US20100186451, WO2002068352A2, WO2002068352A3
Publication number10468669, 468669, US 2005/0087213 A1, US 2005/087213 A1, US 20050087213 A1, US 20050087213A1, US 2005087213 A1, US 2005087213A1, US-A1-20050087213, US-A1-2005087213, US2005/0087213A1, US2005/087213A1, US20050087213 A1, US20050087213A1, US2005087213 A1, US2005087213A1
InventorsKarlheinz Hahn
Original AssigneeHahn Karlheinz U.G.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Water-soluble glass as corrosion protector in dishwashing machines
US 20050087213 A1
Abstract
A zinc-containing, water-soluble glass composition comprising from 41 to 54 mole % of P2O5, 10 to 30 mole % of alkali oxides, up to 5 mole % of SO3 and up to 25 mole % of ZnO.
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Claims(19)
1. A zinc-containing, water-soluble glass composition comprising:
from 41 to 54 mole % of P2O5,
10 to 30 mole % of alkali oxides,
up to 5 mole % of SO3 and
up to 25 mole % of ZnO.
2. The composition according to claim 1 characterised in that not more than 40 mole % of the total amount of alkali oxides in the composition is constituted by one or more members of the group consisting of Li2O and Na2O.
3. The composition according to claim 1 characterised in that the composition additionally comprises at least one alkaline-earth oxide with a total amount of alkaline-earth oxides of less than 20 mole %.
4. The composition according to claim 1 characterised in that the composition additionally comprises at least one oxide of antimony or arsenic present in the composition in an amount of of less than 5 mole %.
5. The composition according to claim 1 characterised in that the composition additionally comprises at least one oxide of an element from the group consisting of silicium, germanium, tin and lead present in the composition in an amount of with a total amount of such oxides of less than 10 mole %.
6. The composition according to claim 1 characterised in that the composition it additionally comprises at least one oxide of an element selected from the group consisting of silicon, aluminium and boron present in the composition in an amount of from 0. 1 to 10 mole.
7. The composition according to claim 1 characterised in that the composition does not comprise more than 0.5 mole-% of oxides of elements from the group IIIb of the Periodic System of Elements.
8. The composition according to claim 1 characterised in that the composition comprises
from 41 to 54 mole % of P2O5,
from 10 to 30 mole % of alkali oxides,
up to 5 mole % of SO3,
up to 25 mole % of ZnO,
less than 5 mole % alkaline-earth oxides, and
from 0.3 to 3 mole % of oxides of elements selected from the group consisting of silicon, aluminium and boron.
9. The composition according to claim 1 characterised in that the composition is present in the form of a transparent shaped body.
10. The composition according to claim 9 characterised in that the shaped body is manufactured by continuous glass manufacturing processes.
11. The composition according to claim 1 any of claims 1 to 8 characterised in that the composition it is present in a comminuted form.
12. The composition according to claim 11 characterised in that the composition is manufactured by the breaking of thin glass plates.
13. The composition according to claim 11 characterised in that the composition is manufactured by a process which includes a milling step.
14. The composition according to claim 13, characterised in that the milled glass has an average particle size of not more than 500 microns.
15. A process for the inhibition of corrosion of glassware in an automatic dishwashing process which comprises the step of: contacting said glassware with a zinc-containing, water-soluble glass composition according to claim 1.
16. A process for the inhibition of corrosion of glassware in an automatic dishwashing process characterised by:
providing a zinc-containing, water-soluble glass composition according to claim 1 at an appropriate place within an automatic dishwashing machine wherein the said composition is accessible to the wash liquor and/or rinse water.
17. A process for the inhibition of corrosion of glassware in an automatic dishwashing process characterised by:
contacting the glassware, in an automatic dishwashing machine, with wash liquor and/or rinse water containing an effective amount of a composition according to claim 1.
18. A process for the inhibition of corrosion of glassware in an automatic dishwashing process characterised by:
providing a zinc-containing, water-soluble glass composition according to claim 9 at an appropriate place within an automatic dishwashing machine wherein the said composition is accessible to the wash liquor and/or rinse water.
19. A process for the inhibition of corrosion of glassware in an automatic dishwashing process characterised by:
contacting the glassware, in an automatic dishwashing machine, with wash liquor and/or rinse water containing an effective amount of a composition according to claim 11.
Description

The invention is related to a novel zinc-containing, water-soluble glass composition, the use thereof for inhibition of corrosion of glassware in an automatic dishwashing process and related processes.

Corrosion of glassware in cleaning and/or rinsing cycles of an automatic dishwashing machine is a well-known problem. It is believed that corrosion of glassware can be seen as two separate phenomena. On the one hand, corrosion is obviously caused by the leakage of minerals from the glass composition, accompanied by the hydrolysis of the silicate network. On the other hand, deposition of silicate material on the glassware may take place. Those phenomena will result, after a certain number of cleaning cycles, to damages on the glassware, such as turbidity, scratches, streaks and the like.

It is known that silicate compounds could be active against leakage of minerals from glass compositions. However, deposition of silicate material on the surface of glassware would be increased.

There are different approaches in the prior art proposed for the solution of above identified problems.

One approach is the use of zinc, either in metallic form (U.S. Pat. No. 3,677,820) or in the form of zinc compounds. The use of soluble zinc salts for inhibition of corrosion of glassware in automatic dishwashing processes is, for example, disclosed in U.S. Pat. No. 3,255,117.

There are, however, various disadvantages of the use of soluble zinc salts, in particular formation of precipitates of insoluble zinc salts with other ions in the wash liquor or rinse water. Thus, the use of insoluble zinc compounds for the inhibition of corrosion of glassware in automatic dishwashing processes has been proposed in European Patent Application EP 0 383 480 A1, EP 0 383 482 A1 and EP 0 387 997 A1. More particularly insoluble zinc salts such as zinc silicate, zinc carbonate, zinc oxide, basic zinc carbonate, zinc hydroxide, zinc oxalate, zinc monophosphate and zinc pyrophosphate have been proposed.

With these prior art compositions, it is disadvantageous that, due to the low solubility, or even insolubility, of the zinc compounds, it is difficult, if not impossible, to ensure an continuously sufficient amount of active corrosion inhibiting agent in the wash liquor or rinse water. Moreover, due to the high specific density of above mentioned insoluble zinc salts, separation problems of powder mixtures or deposition problems with liquid mixtures have occurred.

WO 97/11151 discloses glassy particles containing agents useful for laundry and cleaning products. Amongst others, material care agents are disclosed such as usual corrosion inhibitors such as paraffin oil, benzotriazole, and the like. The agents are encapsulated in glassy particles derived from at least partially water-soluble hydroxylic compounds such as sucrose, glucose and maltodextrin. No zinc-containing water-soluble glass compositions are disclosed therein.

WO 00/39259 discloses the use of water-soluble glasses as corrosion protection for glassware. This water-soluble glass composition comprises at least one compound, which in cleaning and/or rinsing cycles of a dishwashing machine releases a corrosion inhibiting agent. The solubility of the glass is defined by a mass loss of at least 0.5 mg under specified conditions. Amongst others, zinc-containing glasses are disclosed. In preferred embodiments, the glass building component is preferably phosphorous pentoxide and additionally comprises at least one alkali oxide. The examples disclosed therein are characterised by a content of SO3 of around 20%.

However, the glass composition disclosed in WO 00/39259 which is based on ZnO (which is presently believed to be a very effective glassware-protecting agent) turned out to be unsatisfactory for manufacture of a consumer appealing product. In fact, although it is possible, under certain conditions, to manufacture a transparent glass from the composition, this glass looses its transparency rapidly after some dishwashing cycles developing an unappealing appearance.

Related compositions obtained by variation of the components resulted in problems of producing a transparent glass in a continuous manufacturing process, which is required for production of large amounts of the glass product. In such processes, the raw materials for glasses are molten in a furnace at temperatures where they form a liquid glass melt with viscosities from 1 to 1000 dPas (100 dPas characterises the well know “Melting Point”) Afterwards the melt is continuously slowly cooled down and remains during a long period working temperature range where it shows a viscosity of 104 to 108 dPas. This is called the processing range of glass, determined by the “Working Point”, where the liquid glass shows a viscosity of 104 dPas and the “Littleton Point”, 107,6 dPas, where the shape of glass is formed by pressing or/and blowing. Finally, the composition reaches the glass transition temperature range (Tg) where its viscosity increases becoming a solid material. In this range (“Annealing Point”, viscosity of 1013 dPas and “Strain Point” 1014,6 dPas) tensions could be minimised due to annealing.

The time during which the glass remains within the working temperature range facilitates devitrification of the glass formulation. In non-continuous processes (such as those employed in the manufacture of optical glasses or glasses used as fillers for plastics), the glass is quickly cooled down after it comes out of the furnace and therefore devitrification does usually not occur. The formulation of the glass is, however, much more critical, when manufacturing transparent glasses in a continuous process with above described prolonged cooling down periods.

Thus, it is an object of the present invention to provide for a zinc-containing, water-soluble glass composition for use as a corrosion inhibiting product in an automatic dishwashing process which allows production of transparent glass in a continuous manufacturing process which glass maintains its transparency upon dissolution over a sufficient number of dishwashing cycles.

This object is solved by a zinc-containing, water-soluble glass composition comprising from 41 to 54 mole % of P2O5, 10 to 30 mole % of alkali oxides, up to 5 mole % of SO3 and up t 25 mole % of ZnO.

In a preferred embodiment of the inventive glass composition not more than 40 mole %, preferably not more than 20 mole%, most preferably not more than 1 Omole % of the total amount of alkali oxides in the glass formulation is constituted by one or more members of the group consisting of Li2O and Na2O.

Preferably, the inventive composition additionally comprises at least one alkaline-earth oxide with a total amount of alkaline-earth oxides of less than 20 mole %, preferably less than 10 mole % and, most preferably less than 5 mole %.

Also preferably, the inventive composition additionally comprises at least one oxide of antimony or arsenic with a total amount of such oxides of less than 5 mole %, preferably less than 3 mole %, most preferably less than 1 mole %.

The inventive composition may comprise oxides of an element from the group consisting of silicium, germanium, tin and lead with a total amount of such oxides of less than 10 mole %, preferably less than 5 mole %, most preferably less than 3 mole %, wherein no single of such oxides is present in an amount exceeding 5 mole %, more preferably 2 mole %.

Even more preferably, the inventive composition additionally comprises at least one oxide of an element selected from the group consisting of aluminium and boron with a total amount of such oxides of from 0.1 to 10 mole %, preferably from 0.2 to 5 mole %, most preferably from 0.3 to 3 mole %.

It is also preferred that the glass compositions according to the present invention do not comprise more than 0.5 mole % of oxides of elements from the group IIIb of the Periodic System of Elements (i.e. the group comprising Scandium, Yttrium, the Lanthanide series and the Actinide series).

The presently most preferred composition according to the invention consists of from 41 to 54 mole % of P2O5, from 10 to 30 mole % of alkali oxides, up to 5 mole % of SO3, up to 25 mole % of ZnO, less than 5 mole % of alkaline-earth oxides, and from 0.3 to 3 mole % of oxides of elements selected from the group consisting of silicon, aluminium and boron.

In the most preferred embodiment of the invention, the composition is present in the form of a transparent shaped body, preferably manufactured by continuous glass manufacturing processes like casting, pressing or blowing.

In an alternative, the composition is present in a comminuted form, preferably either manufactured by breaking of thin glass plates or by milling, wherein the milled glass most preferably has an average particle size of not more than 500 microns.

The invention is specifically related to the use of the inventive glass composition for inhibition of corrosion of glassware in an automatic dishwashing process, particularly to the use of a transparent glass composition, which remains transparent upon dissolution.

Thus, the invention is also related to processes for inhibition of corrosion of glassware in an automatic dishwashing process, either characterised by contacting the glassware, in an automatic dishwashing machine, with wash liquor and/or rinse water containing an effective amount of the inventive composition, or by providing the composition, in particular in the form of a shaped body, such as a glass block drop casted and pressed in a continuous manufacturing process, at an appropriate place within an automatic dishwashing machine being accessible for the wash liquor and/or rinse water.

Very surprisingly, only the specific selection of components in their indicated ranges simultaneously fulfils the requirements of releasing ZnO during the dishwashing cycles in an amount enough to ensure glassware corrosion protection, providing for a dissolution rate of the glass enabling to use a block of reasonable weight for a reasonable number of washing cycles (for example, 40 g for 60 cycles), and allowing manufacture of a transparent glass block in an continuous manufacturing process which glass block does not loose its transparency during a sufficient number of dishwashing cycles.

Although a multitude of glass formulations is known from the prior art, we are presently not aware of any such composition with this specific choice of components in the specified ranges. In particular, above mentioned advantageous features enabling the desired use of the glass composition for manufacturing a consumer appealing glass product for inhibition of corrosion of glassware in automatic dishwashing has neither been anticipated nor obvious for someone skilled in the art from the prior art documents related to glass formulations.

The compositions as exemplified in the following Table have been produced in a continuous commercial glass pressing processing as outlined hereinabove. It is easily possible to manufacture shaped bodies of transparent glass with a weight of about 40 g. When used an automatic dishwashing machine, the glass block was completely dissolved after several dishwashing cycles. For example 1 a glass block with the dimensions (1×5×3) cm3 was completely dissolved after 60 cycles in the dishwasher, if you choose the conditions described in prEN 12875-1 with Calgonit Powerball Tab as detergent. No loss of transparency of the glass block was observed over this time period.

The glass corrosion inhibiting activity of these glass blocks were tested according the methods as described in detail in WO 00/39259. The results were found to be at least equal, in case of the composition according to Example 1 even significantly better.

TABLE
Component Exp. 1 [mole %] Exp. 2 [mole %] Exp. 3 [mole %]
P2O5 50 45 43
Na2O 1 0 0
Li2O 0 3 0
K2O 27.5 25 29
ZnO 14.5 15 19
CaO 3 5 0
SO3 0 4.5 3
Sb2O3 0 0.5 0
SiO2 2 0 3
Al2O3 0.5 0 1
B2O3 1.5 2 2
Total 100 100 100

The features disclosed in the foregoing description, and the claims may, both separately and in any combination thereof, be material for realising the invention in diverse forms thereof.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7456142 *Jul 11, 2007Nov 25, 2008Reckitt Benckiser N.V.washing the glassware with a composition comprising P2O5, Li2O or Na2O, SO3 and ZnO; keeping transparency
US7709434May 2, 2008May 4, 2010Ecolab Inc.Compositions including Ca and Mg ions and gluconate and methods employing them to reduce corrosion and etch
US7741262Oct 31, 2008Jun 22, 2010Ecolab Inc.EDTA-free, phosphorus-free, zinc-free, aluminum-free; cleaning instruments such as medical or dental equipment; water soluble magnesium and calcium salts, gluconate, alkalinity and chelating agent
US7749329May 2, 2008Jul 6, 2010Ecolab Inc.Cleaning compositions containing water soluble magnesium compounds and methods of using them
US7919448Mar 17, 2010Apr 5, 2011Ecolab Usa Inc.Hard surface cleaner; low or free of zinc, aluminum, and phosphorus
US7922827May 24, 2010Apr 12, 2011Ecolab Usa Inc.Cleaning compositions containing water soluble magnesium compounds and methods of using them
US7960329May 2, 2008Jun 14, 2011Ecolab Usa Inc.Compositions including magnesium ion, calcium ion, and silicate and methods employing them to reduce corrosion and etch
US8021493May 2, 2008Sep 20, 2011Ecolab Usa Inc.Cleaning compound mixture containing detergent, surfactant, base to adjust pH, corrosion resistant and diluting water; detergent contains water insolubility calcium and magnesium salts; precipitation to form protective coating on substrate
US8071528May 2, 2008Dec 6, 2011Ecolab Usa Inc.Reduce scale formation on an article during a cleaning process; magnesium hydroxide, water insoluble source of magnesium ion; sodium carbonate; sodium hydroxide; surfactants; solid composition partially dissolves in water with calcium hardness to precipitate as a non-calcite crystal of aragonite
US8207102May 2, 2008Jun 26, 2012Ecolab Usa Inc.Compositions including hardness ion and threshold agent and methods employing them to reduce corrosion and etch
US8464553 *Feb 5, 2010Jun 18, 2013Schott AgProduction of a pharmaceutical container from the melt
US20100203270 *Feb 5, 2010Aug 12, 2010Andreas LangsdorfProduction of a pharmaceutical container from the melt
Classifications
U.S. Classification134/25.1, 501/73, 501/45
International ClassificationC11D3/00, C03C3/19, C03C3/072, C03C3/074, C03C3/064, C03C3/066, C03C3/062, C03C3/16, C03C3/07, C11D3/08, C03C3/17, C11D7/04
Cooperative ClassificationC03C3/16, C03C4/0064, C11D3/0073, C03C4/0035, C11D3/08, C03C2218/355
European ClassificationC03C4/00L, C03C4/00D, C11D3/00B15, C11D3/08, C03C3/16
Legal Events
DateCodeEventDescription
Feb 23, 2007ASAssignment
Owner name: RECKITT BENCKISER N.V., NETHERLANDS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:RECKITT BENCKISER N.V.;REEL/FRAME:018930/0483
Effective date: 20060627
Owner name: RECKITT BENCKISER N.V.,NETHERLANDS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:RECKITT BENCKISER N.V.;US-ASSIGNMENT DATABASE UPDATED:20100413;REEL/FRAME:18930/483
Feb 13, 2004ASAssignment
Owner name: RECKITT BENCKISER N.V., NETHERLANDS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HAHN, KARLHEINZ ULRICH GERHARD;REEL/FRAME:014336/0993
Effective date: 20040210