Method for the preparation of a degreasing product and the product resulting therefrom

Description

[0001] The object of the present invention relates to preparing and obtaining a solid detergent preferably, though not exclusively, used in industrial contexts, such as in industrial dishwashers.

State of the art

[0002] It is known that the detergents known and currently used in the washing of kitchenware use caustic soda (sodium hydroxide) as a base of their composition. This component develops its detergent capacity in a directly proportional way to its percentage amount in relation to the other components, i.e. in relation to its concentration.

[0003] In liquid detergents of this type caustic soda cannot be present in concentrations greater than 10-20% by weight, in order to avoid phase separations in the detergent. As a result the cleaning power of such detergents is limited.

[0004] In order to overcome this drawback, powder detergents have been provided wherein the concentration of caustic soda is increased. In any case, this type of detergent also presents problems. In fact, the detergent container must be inserted into the doser of the dishwasher machine top down, in order to allow for the detergent to be withdrawn by suitable jets of water: it is therefore understood that the opening of the container must be screened by a net to hold the detergent not dissolved by the jets of water. After repeated use (a detergent container serves for several washes) this net in any case tends to become blocked due to the formation of lumps, thus preventing or making difficult, further withdrawal of detergent.

Object and description of the invention

[0005] The object of the present invention is to provide a detergent for industrial use, in particular a detergent for dishwasher machines that overcomes the drawbacks stated above.

[0006] This problem is solved by an industrial use detergent composition as set out in the attached claims.

[0007] A further object of the present invention is a method of preparing said detergent.

[0008] The industrial use detergent according to the invention is a solid mass or agglomerate comprising an alkali metal or alkaline earth metal hydroxide and a medium , characterised by the fact that said medium is glycerol and/or a homologue or isomer.

[0009] The alkali metal or alkaline earth metal hydroxide will preferably be selected from sodium, potassium or calcium hydroxide. More preferably, it will be sodium hydroxide.

[0010] By the term "homologue" of glycerol is meant a superior homologue such as butantriol, pentantriol and similar.

[0011] By the term "isomer" of glycerol is meant a propanetriol different from 1,2,3-propanetriol, such as 1,1,2-propanetriol or 1,1,3-propanetriol.

[0012] The medium will preferably be glycerol. Without wishing to be linked to any theory, it is not excluded that in the conditions of preparation, storage and use of the detergent of the invention, the glycerol may, at least partially, salify thanks to the action of the hydroxide. Therefore, the term "glycerol", as used herein, can comprise glycerol in the true sense of the word, its mono-, bi and tribasic salts and mixtures thereof.

[0013] The glycerol and the alkali metal or alkaline earth metal hydroxide will be present in the detergent composition of the invention in ratios ranging between 1 : 4 and 4 : 1. Preferably the detergent composition will contain alkali metal or alkaline earth metal hydroxide in weight amounts ranging between 20% and 50%, more preferably between 22% and 30% and glycerol in weight amounts ranging between 10 and 55%, more preferably between 10% and 40%.

[0014] In the detergent composition of the invention various other additives may optionally be present, such as, surfactants, water softeners such as tripolyphosphates, other sources of alkalinity, colouring agents and inorganic cation complexants. Other possible additives will be selected from builder, viscosing agents, anti-redeposition agents, enzymes, oxidising or reducing bleach liquors, foam reducing agents, antimicrobe agents, perfumes and others. Such additives, absolutely conventional, can be used alone or in blends and in amounts dictated by the single requirements, as is well known to a man skilled in the art.

[0015] Any type of surfactant can be used in the composition of the invention, such as anionic, non-ionic, cationic or amphoteric surfactants.

[0016] Preferably non-ionic surfactants will be used, optionally in combination with hydrotrope surfactants, such as sodium xylensulfonate (commercial product SX 93% powder). The use of surfactants is required in the case in which the detergent composition of the invention must be for example used either in industrial laundries or as a detergent for industrial floor washing; typically, but not always, it is used in lower amounts or can be eliminated in the application in dishwashers. When the composition of the invention will contain surfactants, such additives will be present normally in amounts of between 0.2 and 2% by weight. It is not however excluded the use of hypersurfactant compositions, containing up to approximately 30% by weight of surfactants. If in any case the composition of the invention will be used as an industrial detergent for laundries, it will contain an amount of surfactants ranging between 10% and 30% by weight, together with other additives such as optic bleach liquors (0.1-0.3% by weight) and carboxymethylcellulose (0.5-1.5% by weight). If however the composition of the invention will be used as a concentrated floor cleaner, it will contain between 1% and 10% of surfactants.

[0017] Preferred tripolyphosphates will be sodium tripolyphosphates. The tripolyphosphates will generally be used in amounts ranging between 1% and 23% by weight.

[0018] As additional sources of alkalinity, metasilicates or orthosilicates, phosphates, carbonates, sodium or potassium sesquicarbonates or bicarbonates, sodium and potassium borates and metaborates, amines such as mono-, di- and tri-ethanolamine may be used. Preferred metasilicates or orthosilicates will be sodium or potassium metasilicate or orthosilicate. Preferred phosphates will be alkali metal phosphates, condensed or cyclic phosphates, pyrophosphates. Such additional sources of alkalinity will generally be used in amounts ranging between 5% and 15% by weight.

[0019] The inorganic cation complexants are preferably selected among salts of: 2-phosphanobutane-1,2,4-tricarboxylic acid (PBTC), N-hydroxyethylamine diacetic acid, nitrilotriacetic acid (NTA), ethylenediamine tetracetic acid (EDTA), N-hydroxyethylaminetriacetic acid (HEDTA) and diethylenetriaminepentacetic acid (DTPA). Other possible inorganic cation complexants will be selected from water soluble acrylic polymers, such as polyacrylic acid, polymethacrylic acid and their copolymers, hydrolised polyacrylamide, hydrolised polymethacrylamide and their copolymers, or blends thereof, including salts thereof. Such polymers will be used in a molecular weight range between 4000 and 12000, more preferably between 4000 and 8000. Sodium polyacrylate with a molecular weight ranging between 4000 and 8000 is the preferred variety. Alternatively or in addition to such complexant agents phosphates such as those listed above may also be employed.

[0020] Particularly preferred inorganic cation complexants will be ethylenediaminetetraacetic acid (EDTA) or nitrilotracetic acid (N,N-bis(carboxymethyl)glycine, NTA) or blends thereof in a NTA/EDTA ratio of 3:1 - 1:15. The presence in the composition of a certain amount of EDTA, although not indispensable, seems to favour the formation of the solid agglomerate according to the invention.

[0021] Said complexant will be present in the detergent composition of the invention in amounts ranging between 5% and 40%.

[0022] Besides, the composition of the invention will be able to contain secondary solidifying agents or solubility modifiers, such as an amide (stearic acid monoethanolamide or lauric acid diethanolamide), an alkylamide, a solid polyethylene or polypropylene glycol, amides modified and made water soluble by treatment with acids or bases. Such solidifying agents will be present in the composition of the invention in weight amounts of between 5% and 20%, preferably between 10% and 15%.

[0023] The detergent composition of the invention is obtained according to the method described below.

[0024] A suspension of the medium (glycerol and/or a homologue or isomer thereof) is prepared with the optional additives, preferably selected from those listed above, and this suspension is heated to a temperature that may range between 50°C and 100°C. In this way the blend is maintained in a fluid state. To this blend is added the alkali metal or alkaline earth metal hydroxide, preferably in beads or in a solid state. An exothermia of the blend occurs and, after about 10 - 15 minutes, a more rigid mass is formed, that within 24 hours can be defined solid agglomerate. In the period elapsing between the addition of the hydroxide and hardening it is necessary to complete the transfer of the detergent composition into the final use containers.

[0025] Such containers will be generally applied to washing machines or dishwashers fitted with dissolution devices that use water jets directed towards the detergent. The water jet dissolves the necessary amount of detergent composition that is thus made available for the washing.

[0026] In alternative, the still fluid blend of the invention composition can be transferred into suitable moulds until solidification and then transferred into water soluble containers, such as, for example, sachets. For example, water soluble plastic sachets, water soluble films, paper and cardboard may be used. This enables to introduce the thus wrapped inventive composition directly into the funnel doser of the dishwasher.

[0027] The invention composition can also be extruded, when still in its plastic phase, so as to form small pieces, such as small bricks or spheres, to be wrapped in water soluble packaging as described above.

[0028] As an example, the preparation of three detergent compositions in accordance with the invention will now be described.

EXAMPLE 1 - Preparation of a detergent composition for dishwashers

[0029] To 28 kg of glycerol are added 3 kg of atomised tripolyphosphate, 26 kg of NTA, 10.5 kg of EDTA in powder, 8 kg of anhydrous sodium metasilicate and 6 gr of colouring (yellow tartrazine E 102). The resulting mother suspension is heated to a temperature of 60-70°C.

[0030] To this suspension is added 24.5 kg of sodium hydroxide in beads. An exothermal reaction develops immediately. The suspension, still fluid, is distributed in the final use containers, inside which first a hardening within the course of 15 minutes and then the solidification of the mass occur, which reaches consistent levels within 24 hours in concomitance with the cooling of the same.

EXAMPLE 2 - Preparation of a detergent composition for dishwashers

[0031] The method of example 1 is repeated, but with the following amounts :

mother suspension
glycerol	36.7 kg
matrix (non ionic surfactant)	0.8 kg
atomised tripolyphosphate	18 kg
SX 93% powder (hydrotrope surfactant)	1 kg
Anhydrous sodium metasilicate	11 kg
EDTA powder	8 kg
colouring (yellow)	6 gr

alkali addition
sodium hydroxide beads	24.5 kg

EXAMPLE 3 - Preparation of a detergent composition for dishwashers

[0032] The method of example 1 is repeated, but with the following amounts :

mother suspension
glycerol	38.7 kg
non ionic surfactant MATRIX	1.044 Kg
atomised tripolyphosphate	3.5 kg
yellow tartrazine E 102	0.006 kg
SX 93% powder	1 kg
sodium polyacrylate
homopolymer PM 4000-8000	10 kg
EDTA sodium salt powder	9.25 kg
Anhydrous sodium metasilicate	12 kg

alkali addition
sodium hydroxide beads	24.5 kg

[0033] The reaction occurs with high exothermicity.

[0034] The detergent composition allows to overcome the disadvantages inherent to prior art industrial detergents. In fact, the solid mass is in the form of a single block and thus does not require the presence of holding nets or septums on the mouthpiece of the use container.

[0035] Besides, the detergent of the invention, thanks to the fact that it is a solid, can contain high amounts of caustic hydroxide, thus resulting in a better cleaning effect.

[0036] Finally, glycerol has, together with the inorganic cation complexants, a control effect on the hardness of the water and provides anticorrosive and detergent properties to the composition.

[0037] It should be noted that the presence of water in the composition does not play a fundamental role in the solidification of the same, although in fact a certain amount of water (0.1 - 3% by weight) will be generally present due to the use of ingredients that are not always anhydrous, it will also be possible to operate in anhydrous conditions without departing from the scope of the present invention.

[0038] It should also be noted that the presence of phosphonates is not indispensable for the purposes of the invention. Their presence may therefore be avoided.

[0039] The detergent composition according to the invention can be used in various sectors, such as an alkylating agent or detergent in milking machines, or as an industrial detergent for laundries or for cleaning floors, with small modifications to the composition within the claimed ranges.

Claims

1. A detergent composition comprising an alkali metal or alkaline earth metal hydroxide and a medium, characterised in that said medium is glycerol and/or a homologue or isomer thereof.

2. The detergent composition according to claim 1, wherein said alkali metal or alkaline earth metal hydroxide is selected between sodium hydroxide, potassium hydroxide or calcium hydroxide.

3. The detergent composition according to claim 1, wherein said detergent composition is in the form of a solid mass.

4. The detergent composition according to claim 1 o 2, wherein said hydroxide is sodium hydroxide.

5. The detergent composition according to any of claims 1 to 4, wherein said homologue of glycerol is selected from butantriolsorpentantriols.

6. The detergent composition according to any of claims 1 to 5, wherein said glycerol and/or the homologue or isomer thereof and said alkali metal or alkaline earth metal hydroxide will be present in weight ratios ranging between 1 : 4 and 4 : 1.

7. The detergent composition according to claim 6, wherein said alkali metal or alkaline earth metal hydroxide is present in weight amounts ranging between 20% and 50%, preferably between 22% and 30%, and said glycerol and/or the homologue or isomer thereof is present in weight amounts ranging between 10% and 55%, preferably between 10% and 40%.

8. The detergent composition according to any of claims 1 to 7, further comprising additives selected from surfactants, water softeners such as tripolyphosphates, additional sources of alkalinity, colouring agents and inorganic cation complexants.

9. The detergent composition according to claim 8, wherein said surfactants are present in amounts ranging between 0.2 and 30% by weight, preferably between 0.2% and 2%, in the case of use in dishwashers, between 10% and 30% by weight in the case of use in laundries, or between 1% and 10% by weight in the case of use as a detergent for floors.

10. The detergent composition according to claim 8 or 9, wherein said surfactants are non ionic, preferably in combination with hydrotrope surfactants, such as sodium xylensulfonate.

11. The detergent composition according to claim 8, wherein said tripolyphosphates are sodium tripolyphosphates, and wherein said tripolyphosphates are present in amounts ranging between 1% and 23% by weight.

12. The detergent composition according to any of claim 8 to 11, wherein said additional sources of alkalinity are selected from sodium or potassium ortho-or metasilicate, phosphates, carbonates, bicarbonates or sesquicarbonates of sodium or potassium, metaborates and borates of sodium and potassium, amines such as mono-, di-, or triethanolamines.

13. The detergent composition according to claim 12, wherein said additional sources of alkalinity are present in amounts ranging between 5% and 15% by weight.

14. The detergent composition according to any of claims 8 to 13, wherein said inorganic cation complexants are selected from ethylenediamine tetraacetic acid (EDTA), nitrolotracetic acid (N,N-bis(carboxymethyl)glycine, NTA) or blends thereof in an NTA/EDTA ratio of 3:1 - 1:15.

15. The detergent composition according to any of claims 8 to 13, wherein said inorganic cation complexants are selected from water soluble acrylic polymers, such as polyacrylic acid, polymetacrylic acid and copolymers thereof, hydrolysed polyacrylamide, hydrolysed polymetacrylamide and copolymers thereof, hydrolysed polyacrylonitrile, hydrolysed polymetacrylonitrile and copolymers thereof, or mixtures thereof including salts thereof, and having a molecular weight ranging between 4000 and 12000, preferably between 4000 and 8000.

16. The detergent composition according to any of claims 8 to 15, wherein said complexant is present in amounts ranging between 5% and 40% by weight.

17. The detergent composition according to any of the claims 8 to 16, comprising secondary solidifying agents or solubility modifiers, selected from an amide (stearic acid monoethanolamide or lauric acid diethanolamide), an alkylamide, a solid polyethylene or polypropylene glycol, amides modified and made water soluble by treatment with acids or bases, in weight amounts ranging between 5% and 20%, preferably between 10% and 15%.

18. A method for the preparation of the detergent composition according to any of the claims 1 to 17, comprising the following operative steps:

a) heating the glycerol and/or a homologue or isomer thereof to a temperature of between 50°C and 100°C, optionally blended with additives selected from surfactants, water softeners such as tripolyphosphates, metasilicates, colouring agents, inorganic cation complexants, additional sources of alkalinity, polyphosphates, secondary solidifying agents or solubility modifiers;

b) Adding a predetermined amount of a alkali metal or alkaline earth metal hydroxide to the medium obtained in said steps a), thus obtaining a solid mass of final product.

19. The method according to claim 18, further comprising step c) of transferring said blend obtained in step b) into the final use containers or into moulds, prior to solidification.

20. The method according to claim 18, further comprising step c2) of extrusion of the blend obtained in step b) to obtain the solid composition in pieces.

21. The method according to claim 19, wherein said solidified composition is introduced in water soluble wrapping for final use.

22. Use of the detergent composition obtainable with the method according to any of the claims 18 to 21 as industrial detergent for dishwashers, laundries or floor cleaning.