WO2015155525A1

WO2015155525A1 - Particulate zeolite composition

Info

Publication number: WO2015155525A1
Application number: PCT/GB2015/051070
Authority: WO
Inventors: Suwitanan BOONSRI; Wichet KHAMSIANG; Prateep UDOMPUESH
Original assignee: Pq Silicas Uk Limited
Priority date: 2014-04-08
Filing date: 2015-04-08
Publication date: 2015-10-15
Also published as: ZA201606564B; GB201406268D0; CN106232522A; TR201614069T1

Abstract

A particulate, crystalline zeolite composition which comprises particles of co- crystallised zeolite A and zeolite HS, said composition having a calcium binding capacity of 20 to 120mg CaO/g anhydrous zeolite and/or an oil absorption of at least 60 g oil per 100 g of zeolite composition. The zeolite A and zeolite HS are preferably both in their sodium forms. Also disclosed is a particulate or granula detergent or detergent additive formulation which comprises particles of the zeolite composition and at least one surfactant absorbed by the particles.

Description

Particulate Zeolite Composition

Field The present invention relates to a particulate zeolite composition which is intended particularly, but not necessarily exclusively, for use in producing a particulate or granular detergent or detergent additive formulation comprised of the particulate zeolite composition and a surface active agent absorbed in or on the particles thereof. The zeolite composition is capable of absorbing relatively high amounts of surface active agent (e.g. a liquid non-ionic surface active agent) whilst providing a particulate or granular detergent or detergent additive formulation which is free-flowing.

Background Detergent formulations for use in laundry washing have been, and continue to be, the subject of extensive research and development, both in relation to the chemical nature of the individual components (surfactants, builders, etc.) and also the manner in which such individual components are compounded together to produce a final detergent formulation.

Surfactants (e.g. non-ionic surfactants) of a liquid or pasty nature have been used for many years in the production of water soluble, powdered or granular detergent formulations. For this purpose, the pasty or liquid surfactant (optionally with other components for a detergent formulation) has been absorbed or otherwise incorporated in a particulate or granular material to provide either a final detergent formulation or a detergent additive formulation which may then be mixed with other powdered or granular components to produce a final detergent formulation.

Historically, powdered or granular detergent or detergent additive formulations were produced by the spray-drying of an aqueous slurry which comprises the surfactant(s) and optionally other components of a detergent formulation. Such a procedure has the advantage that the particles produced are relatively porous and dissolve relatively easily in the laundry wash solution. There are however a number of disadvantages associated with the spray-drying procedure. In particular, the powder produced is of relatively low bulk density and thus of relatively high volume, thus increasing packaging requirements. Additionally, spray drying has a relatively high energy requirement and there are also environmental disadvantages in relation to fumes emitted from the spray dryer. In more recent times, there has been a move to the production of detergent or detergent additive formulations by granulation techniques. Such techniques produce products of higher bulk density than the above described spray drying process and are also less energy demanding. Another aspect of detergent formulation relates to the development of builders for ensuring adequate detergent formulation for the case where the water fed to the laundry washing machine contains calcium or magnesium ions, which can have an adverse effect on surfactant performance. For many years, phosphates were used as builders but have now fallen into environmental disfavour due to their eutrophic effect. Zeolites (e.g. zeolite A) have been used as replacements for phosphates as builders. The zeolites contain labile (usually sodium) ions in the zeolite structure which can be exchanged with calcium or magnesium ions in the wash solution, the builder function being provided by virtue of the fact that the calcium and/or magnesium ions remain bound within the zeolite structure. Zeolites are absorbent and can therefore be used for the production of particulate or granular detergent or detergent additive formulations by the absorption of surface active agents. Thus both the ion exchange capability and absorption capacity of zeolites have been regarded as important features for their use in detergent or detergent additive formulations. Thus, for example, Doucil 4A zeolite (a zeolite A) sold by PQ Corporation is stated in promotional literature as having a calcium binding capacity of greater than 155 mg CaO/g zeolite and having a liquid carrying capacity of about 38 g of liquid non-ionic surfactant per 100g of zeolite (the equivalent figures for sodium carbonate ("light"), sodium tripolyphosphate and nitrilotriacetic acid being between 20 and 30 g of liquid non-ionic surfactant per 100 g of the respective absorbent substrate).

Recently, a trend in powdered or granular detergent formulations has been the use of high levels of non-ionic surfactants. This use of high levels of non-ionic surfactants reduces the amount of builder required for the detergent formulation since non-ionic surfactants are relatively unaffected by calcium and magnesium ions. A further feature of the use of high levels of liquid or pasty non-ionic surfactants is that the solid particulate material on or in which they are absorbed must have a high absorption capacity and provide a free-flowing particulate formation without excessive use of the carrier material. The latter feature is important in the case of an insoluble carrier material (e.g. a zeolite) to ensure that the amount of the insoluble carrier material used in the final detergent formulation can be tailored to minimize deposition onto laundered items.

For these reasons, zeolites are now used in detergent formulations for their liquid absorption capability rather than their builder properties.

EP 0 739 977 (The Procter & Gamble Co.) discloses the use of a powder consisting essentially of zeolite A, B, X or mixtures thereof and crystalline zeolite HS for the manufacture of a granular detergent composition or component having a bulk density greater than 650 g/l by mixing a liquid binder (e.g. a surfactant paste comprised of an anionic, cationic, amphoteric, zwitterion or non-ionic surfactant or a mixture thereof) with the powder. The powder material specifically disclosed in the Example of EP 0 739 977 was Zeolite A/HS supplied by Industrial Zeolites (UK) Ltd. which had oil absorption capacity of 45.5 ml/100 g as determined by BS3483:Part 7:1982 (corresponding to ISO 787/5-1980). The oil absorption value provides a representation of the ability of the powder to absorb liquid surfactant and the value obtained for the powder (45.5 ml/100g) was higher than that of 36ml/100 g for Wessalith® (a Zeolite A supplied by Degussa). No products with higher absorption capability, nor method of making such products, is disclosed in EP 0 739 977. There remains a need for a zeolite which is of enhanced liquid absorbing capacity and which may be used in the production of particulate or granular detergent or detergent additive formulations. The present invention is addressed to that need.

Summary of the Invention

The present invention provides particulate, crystalline zeolite compositions which are of high absorption capacity and which are eminently suitable for use in the production of particulate or granular detergent or detergent additive formulations. The zeolite compositions comprise particles of co-crystallised zeolite A and zeolite HS, preferably with at least 90% by weight of the particles having a size less than 20 μιη and/or a mean particle size in the range of 1 to 10 μιη. In one (the first) aspect of the invention, the particulate zeolite composition has a calcium binding capacity of 20 to 120 mg CaO/g anhydrous zeolite. Zeolites in accordance with this aspect of the invention are capable of having an oil absorption value of at least 60 g oil per 100 g of the zeolite composition and are a significant advance over prior art zeolite A/zeolite HS compositions as disclosed in EP 0 739 977 in terms of their ability to absorb surfactants. Zeolite compositions comprising particles of co-crystallised zeolite A and zeolite HS having oil absorption values of at least 60 g oil per 100 g of the zeolite composition are an important feature of the invention in their own right and provide a further (second) aspect thereof. Preferred zeolite compositions in accordance with the invention have a calcium binding capacity of 20 to 120 mg CaO/g anhydrous zeolite and an oil absorption value of at least 60 g oil per 100 g of the zeolite composition.

In the zeolite compositions of the first and second aspects of the invention, the co- crystallised zeolite A and zeolite HS are preferably in their sodium forms.

Further aspects of the invention relate to particulate or granular detergent or detergent additive formulations which comprise crystalline particles of co-crystallised zeolite A and zeolite HS, preferably in their sodium forms, and at least one surfactant absorbed by the particles, wherein the particles free of absorbed material preferably have a calcium binding capacity of 20 to 120 mg CaO/g anhydrous zeolite and/or an oil absorption value of at least 60 g of oil per 100 g of the zeolite particles. Preferably the crystalline particles of co-crystallised zeolite A and zeolite HS have a size distribution such that at least 90% by weight have a size less than 20 μιη and/or a mean particle size in the range 1 to 10 μιη.

Preferred zeolite compositions consist essentially of or consist of the particles of co- crystallised zeolite A and zeolite HS. Alternatively or additionally, the co-crystallised particles preferably consist essentially of or consist of zeolite A and zeolite HS.

Definitions

Throughout this specification, the term "comprising", "comprises" or "comprised of" means including the component(s) specified but not to the exclusion of the presence of others. The term "consisting essentially of" or "consists essentially of" means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to manufacture the components, and components added for a purpose other than achieving the technical effect of the invention. Typically, a composition consisting essentially of a set of components may comprise less than 10% by weight, more typically less than 5% by weight, and even more typically less than 1 % by weight of non-specified components.

The term "consisting of" or "consists of" means including the components specified excluding other components.

Whenever appropriate, the term "comprises", "comprising" or "comprised of" may also be taken to include the additional meanings "consisting essentially of", "consists essentially of", "consists of" or "consisting of".

Oil absorption values referred to herein are as determined in accordance with ISO 787/5 - 1980 and are expressed as grams of oil per 100 g of zeolite particles.

Surfactant absorption values are determined using an Absorptometer C (supplied by Brabender GmbH & Co, Germany) and a method based on ASTM D2414 for measurement of the absorption of oil by carbon black. In the method, 30 g of the zeolite under investigation is placed in the sample chamber of the Absorptometer C. A liquid surfactant (Synperonic® A3, a non-ionic surfactant supplied by Croda International, see infra for composition details) is added to the sample at a rate of 4 ml/minute while the mixing blades of the Absorptometer C rotate at 125 rpm. The instrument measures the torque in the mixture, which increases as the liquid is added until the powder is saturated. Further addition of liquid at this point reduces the torque. The instrument is programmed to turn off both burette and mixer 10 seconds after maximum torque in the mixer is reached; the amount of surfactant added at this point corresponds to the surfactant absorption value of the sample.

Calcium Binding Capacity (CBC) values (expressed in mg CaO per g of the zeolite composition) are determined in accordance with the method described in GB 1 473 201 . In this test, an accurately weighed sample of the zeolite, corresponding to 1 g of the anhydrous zeolite, was dispersed in 1 litre of an aqueous solution of 0.594 g of CaCI₂ (equivalent to 300 mg of CaO per litre) and the pH adjusted to 10, if necessary, with dilute NaOH. The suspension is stirred vigorously for 15 minutes at 22C (+/-2C) after which a 250ml sample of the suspension is filtered using a Buchner funnel. The residual calcium content of the solution (x mg per litre of CaO) is determined and the calcium binding capacity of the zeolite calculated as 300-x mg of CaO.

Particle sizes and particle size distributions as referred to herein are by weight and are determined using a Malvern Mastersizer 2000 equipped with the sample dispersion unit Hydro 2000S (supplied by Malvern Instruments Ltd., UK). Measurement of particle size was carried out with the zeolite dispersed in demineralized water, with 150 seconds of sonication (tip displacement 40%) before measurement and a stirrer speed of 2450 rpm in the sample dispersion unit. Particle size distributions were calculated using Mie theory assuming a sample Rl of 1.5295 and an absorption coefficient of 0.1 . Detailed Description of the Invention

As outlined above, the invention provides particulate zeolite compositions having an absorbency which renders them eminently suitable for the production of particulate or granular detergent or detergent additive formulations which comprise at least one surfactant absorbed on or in the zeolite particles. The invention has been based on the surprising finding that it is possible to produce zeolite particles which comprise co- crystallised zeolite A and zeolite HS and which have a much higher liquid absorption capacity than the product disclosed in EP 0 739 977. Zeolite compositions in accordance with the first aspect of the invention have a calcium binding capacity of 20- 120 mg CaO/g anhydrous zeolite and typically have an oil absorption value of at least 60 g oil per 100 g of the zeolite composition. This compares with the value of 45.5 ml/100 g (equivalent to 42.77 g/100 g - taking the specific gravity of linseed oil to be 0.94) quoted for the zeolite A/HS investigated in EP 0 739 977. Preferred embodiments of zeolite composition in accordance with the first aspect of the invention have a calcium binding capacity of 40-120 mg CaO/g anhydrous zeolite, even more preferably 40-100 mg CaO/g anhydrous zeolite. Alternatively or additionally preferred embodiments of zeolite composition in accordance with the first aspect of the invention have an oil absorption value of at least 65 g oil per 100 g of the zeolite composition, with some embodiments of zeolite composition in accordance with the first aspect of the invention having an oil absorption of at least 70 g oil per 100 g of the zeolite composition. Embodiments of zeolite composition in accordance with the first aspect of the invention can have oil absorption values up to 80 g or even 85 g oil per 100 g of the zeolite composition. More generally, zeolite compositions in accordance with the first aspect of the invention have an oil absorption value of 60 g to 85 g oil per 100 g of the zeolite composition. Embodiments of the zeolite compositions may have an oil absorption value of 60 g to 80 g (e.g. 60 g to 75 g) oil per 100 g of the zeolite composition.

Correspondingly preferred zeolite compositions in accordance with the second aspect of the invention have an oil absorption value of at least 65 g oil per 100 g of the zeolite composition, with some embodiments of zeolite composition in accordance with the second aspect of the invention having an oil absorption of at least 70 g oil per 100 g of the zeolite composition. Embodiments of zeolite composition in accordance with the second aspect of the invention can have oil absorption values up to 80 g or even 85 g oil per 100 g of the zeolite composition. More generally, zeolite compositions in accordance with the second aspects of the invention have an oil absorption value of 60 g to 85 g oil per 100 g of the zeolite composition. Embodiments of the zeolite compositions may have an oil absorption value of 60 g to 80 g (e.g. 60 g to 75 g) oil per 100 g of the zeolite composition. Zeolite compositions in accordance with the second aspect of the invention therefore similarly have higher oil absorption values than for the zeolite A/HS investigated in EP 0 739 977.

Zeolite compositions in accordance with the first and second aspects of the invention preferably have a particle size distribution such that at least 90% by weight of the particles have a size less than 20 μιη. More preferably, at least 90% by weight of the particles have a size less than 15 μιη, e.g. less than 10 μιη. Alternatively or additionally, the zeolite particles will preferably have a mean particle size in the range 1 to 10 μιη, more preferably 2 to 8 μιη. The preferred zeolite compositions may be produced by reaction of aqueous solutions of sodium aluminate and sodium silicate prepared in concentrations, and mixed together in such proportions, that the overall mixed solution has the following molar ratios.

(3.5 - 5.5)Na₂O.AI₂0₃. (1.9-2.1 )SiO_z. (80-95)H₂O. More preferably, the ratios are:

(3.5-5.0)Na₂O.AI₂O₃.(1.9-2.1 )SiO2. (80-90)H₂O. The zeolite composition can be prepared by intensive mixing of the sodium aluminate and sodium silicate solutions at a temperature above 70°C. The resulting mixed solution forms a gel which is maintained above 70°C (e.g. at 95°-100°C) with mixing. The reaction proceeds with crystallisation and the conditions are maintained to form particles of co-crystallised zeolite A and zeolite HS having the parameters defined for the first and/or second aspects of the invention.

The product of crystallisation will generally be a slurry which may then be cooled using a flash evaporator, filtered and washed with de-ionised water. Zeolite compositions comprising particles of co-crystallised zeolite and zeolite HS, preferably in their sodium forms, with the composition being such as to have a calcium binding capacity of 20-120mg CaO/g of anhydrous zeolite and/or an oil absorption value of at least 60 g oil per 100 g of the zeolite composition are eminently suitable for the production of particulate or granular detergent or detergent additive formulations by absorption of liquid or pasty compositions comprising at least one surfactant and optionally other components of a detergent formulation. Particularly suitable such compositions are those having a particle size distribution such that at least 90% by weight of the particles have a size less than 15 μιη and/or a mean particle size in the range 1 to 10 μιη. The zeolite composition has a high absorption capacity for liquid or pasty compositions comprising a surfactant. The surfactant may, for example, be an anionic, cationic, zwitterionic or amphoteric surfactant. However, the zeolite compositions are most especially useful in the case where the surfactant is a non-ionic surfactant since high loadings of such surfactants may be achieved using the zeolite composition. Such non-ionic surfactants to be absorbed by the zeolite composition preferably comprise at least one ethoxylated long chain alcohol, most preferably such a surfactant in which the residue of the alcohol has 12 to 20, even more preferably 12 to 15, carbon atoms. For example, embodiments of zeolite composition in accordance with the invention are capable of absorbing of at least 70 g of Synperonic® A3 per 100 g of the zeolite composition using the test described herein (Synperonic® A3 is a non- ionic surfactant supplied by Croda International comprising the residue of an alcohol having 12 to 15 carbon atoms, the surfactant incorporating an average of three oxyethylene units per alcohol residue).

The particulate or granular detergent or detergent additive formulation may be produced by admixing the zeolite composition with the liquid or pasty composition comprising the surfactant using techniques that are well established in the art, e.g. a high speed mixer. The liquid or pasty composition may incorporate surfactant(s), with the resulting product being a detergent additive formulation which may be compounded with other ingredients for a detergent formulation to produce a final product. Alternatively, the liquid or pasty surfactant composition incorporating the surfactant(s) may additionally incorporate other components of a detergent formulation such as to produce a final detergent formulation per se.

In spite of the high surfactant loadings that may be achieved using the zeolite composition, the invention allows the production of free-flowing particulate or granular detergent or detergent additive formulations. These formulations may comprise agglomerates of the zeolite particles bound together by the surfactant.

The invention will be illustrated with reference to the following non-limiting Examples. In the Examples, all percentages are on a weight basis, unless otherwise stated.

Example 1

A zeolite composition in accordance with the invention was synthesised using a sol-gel process from sodium aluminate and sodium silicate solutions which were prepared and reacted in accordance with the following procedure.

To prepare the sodium aluminate solution, a 30 m³ steel reactor was charged with 16,105 kg of aqueous sodium aluminate mother liquor (0.40% Al₂0₃, 8.50% Na₂0) and 1 ,778 kg of 50% aqueous sodium hydroxide solution (38.75% Na₂0). The resultant mixture was then heated to 101 °C by passage through a plate heat exchanger. 2,179 kg of alumina trihydrate ATH, (62%AI₂0₃) was then added to the heated solution which was maintained at 101 °C with mixing for about 30 minutes to ensure most of the ATH was digested to produce the sodium aluminate solution for use in the synthesis. Separately, an aqueous solution of sodium silicate (the solution containing 25.50% Si0₂ and 16.80% Na₂0) having a total weight 6,443 kg and a temperature of 85°C was prepared. Considered together, the sodium aluminate and sodium hydroxide solutions had the following molar ratios - 3.65 Na₂0. Al₂0₃. 1 .97 Si0₂. 81 H₂0.

A synthesis gel was then prepared by injecting 950 kg/minute of the sodium aluminate solution and 318 kg/minute of the sodium silicate solution (both as prepared above) into a jet mixer and then into an insulated crystalliser vessel equipped with baffles and mixing impellers driven by a 15 kW (20 horsepower) motor. The temperature of the sodium silicate solution was controlled at 80°C.

The gel mixture was then heated to 98-100°C by injection of steam and held at that temperature in the insulated vessel for about 90 minutes.

The product (a slurry) from the crystalliser was cooled to 60-65°C using a flash evaporator. The cooled slurry was filtered by means of a filter press, washed with soft water and then dried through a ring mill dryer at 98°C.

The resulting product was a crystalline solid comprised of particles of co-crystallised sodium forms of zeolite A and zeolite HS, for which the particle size distribution was represented by the following values: ϋ(10) = /.26μηι

D (50) = 5. 12μνη

D (90) = 11.89μνη

The product had a calcium binding capacity of 64 mg CaO per g anhydrous zeolite.

The ability of the product to absorb (i) linseed oil (in accordance with ISO 787/5-1980, and (ii) Synperonic® A3 in accordance with the method outlined above) was determined. Synperonic® A3 is a non-ionic surface active agent, described by its manufacturers (Croda) as an "ethoxylate (3) of a fully saturated C12/C15 alcohol". The results were shown in Table 1 below which also incorporates the corresponding linseed oil and Synperonic® A3 absorption values for Wessalith P, a zeolite A supplied by Degussa. Table 1

It will be noted that the zeolite composition produced in Example 1 , i.e. a composition in accordance with the invention, had a significantly improved absorption capacity for both linseed oil and Synperonic® A3 as compared to Wessalith P.

It will also be noted that the linseed oil absorption value of the product of Example 1 was superior to the zeolite A/HS evaluated for the purposes of EP 0 739 977, that zeolite having an oil absorption capacity of 45.5 ml/100 g (i.e. 42.77 g/100 g).

The zeolite composition of Example 1 was eminently suitable for the use in production of free-flowing detergent and detergent additive formulations.

Example 2

This Example describes production of a zeolite composition in accordance with the invention using seed crystals in conjunction with a sol-gel process.

Preparation of Seed Crystals Seed crystals were prepared in accordance with the following procedure, which is a modification of that described in Example 1.

A 30 m³ steel reactor was charged with 17,231 kg of aqueous sodium aluminate mother liquor (0.40% Al₂0₃, 8.50% Na₂0) and 6,210 kg of 50% aqueous sodium hydroxide solution (38.75% Na₂0). The resultant mixture was then heated to 101 °C by passage through a plate heat exchanger. 2,369 kg of alumina trihydrate (ATH, 62%AI₂0₃) was then added to the heated solution which was maintained at 101 °C with mixing for about 30 minutes to ensure that most of the ATH was digested to produce a sodium aluminate solution. Separately, an aqueous solution of sodium silicate (the solution containing 25.50% Si0₂ and 16.80% Na₂0) having a total weight 6,443 kg and a temperature of 85°C was prepared.

Considered together, the sodium aluminate and sodium hydroxide solutions had the following molar ratios - 5.4 Na₂0. Al₂0₃. 1 .97 Si0_2. 90 H₂0.

A synthesis gel was then prepared by injecting 1050 kg/minute of the sodium aluminate solution and 318 kg/minute of the sodium silicate solution (both as prepared in this part of the Example) into a jet mixer and then into an insulated crystalliser vessel equipped with baffles and mixing impellers driven by a 15 kW (20 horsepower) motor.

The gel mixture was then heated to 98-100°C by injection of steam and held at that temperature in the insulated vessel for about 120 minutes. The product (a slurry) from the crystalliser was cooled to 60-65°C using a flash evaporator. The cooled slurry was filtered by means of a filter press, washed with soft water and then dried through a ring mill dryer at 98°C.

The product was a crystalline solid comprised of particles of co-crystallised zeolite A and zeolite HS with a median particle size of 9.44 μιη. The product was used to provide seed crystals for the synthesis of the final zeolite composition.

Synthesis of Zeolite Composition A 30 m³ steel reactor was charged with 19,605 kg of aqueous sodium aluminate mother liquor (0.40% Al₂0₃, 8.50% Na₂0) and 5,349 kg of 50% aqueous sodium hydroxide solution (38.75% Na₂0). The resultant mixture was then heated to 101 °C by passage through a plate heat exchanger. 2,562 kg of alumina trihydrate (ATH, 62%AI₂0₃) was then added to the heated solution which was maintained at 101 °C with mixing for about 30 minutes to ensure that most of the ATH was digested to produce a sodium aluminate solution.

Separately, an aqueous solution of sodium silicate (the solution containing 25.50% Si0₂ and 16.80% Na₂0) having a total weight 7,586 kg and a temperature of 85°C was prepared.

Considered together, the sodium aluminate and sodium hydroxide solutions had the following molar ratios - 4.95 Na₂0. Al₂0₃. 1 .97 Si0₂. 90 H₂0.

A batch of seed crystals (synthesised as described in the first part of this Example) was prepared by mixing 200 kg of the seed crystals with 1 ,250 kg soft water for 30 minutes in a 3.7 m³ tank. A synthesis gel was then prepared by injecting 1 ,050 kg/minute of the sodium aluminate solution and 318 kg/minute of the sodium silicate solution (both as prepared in this part of the Example) into a jet mixer and then into an insulated crystalliser vessel equipped with baffles and mixing impellers driven by a 15 kW (20 horsepower) motor. Simultaneously, the batch of seed crystals was added directly to the crystalliser vessel over the same time period for addition of the mixture of sodium aluminate and sodium silicate solutions.

The gel mixture was then heated to 98-100°C by injection of steam and held at that temperature in the insulated vessel for about 120 minutes.

The product (a slurry) from the crystalliser was cooled to 60-65°C. The cooled slurry was filtered by means of a filter press, washed with soft water and then dried through a ring mill dryer at 98°C. The resulting product was a crystalline solid comprised of particles of co-crystallised sodium forms of zeolite A and zeolite HS, for which the particle size distribution was represented by the following values:

D(10) = 1.01\\m

D (50) = 7.84μνη D (90) = 15.83μπ\

The product had a calcium binding capacity of 31 mg CaO per g zeolite. The ability of the product to absorb (i) linseed oil in accordance with ISO 787/5-1980 and (ii) Synperonic® A3 in accordance with the method outlined above was measured. The results are shown in Table 2 below, which also includes the corresponding values for the product of Example 1 and Wessalith P (zeolite A).

Table 2

It will be noted from the above Table that the product of Example 2 had a slightly higher oil absorption value than that of Example 1 but a slightly inferior ability to absorb Synperonic® A3. Nevertheless, the product of Example 2 had a superior oil absorption value to that of Wessalith P (zeolite A) and also the product tested for the purpose of EP 0 739 977.

Claims

A particulate, crystalline zeolite composition which comprises particles of co- crystallised zeolite A and zeolite HS, said composition having a calcium binding capacity of 20 to 120mg CaO/g anhydrous zeolite.

A zeolite composition as claimed in claim 1 wherein the co-crystallised zeolite A and zeolite HS are in their sodium forms.

A zeolite composition as claimed in claim 1 or 2 wherein said composition has a calcium binding capacity of 40 to 120 mg CaO/g anhydrous zeolite.

A zeolite composition as claims in claim 3 wherein said composition has a calcium binding capacity of 40 to 100 mg CaO/g anhydrous zeolite.

A zeolite composition as claimed in any one of claims 1 to 4 having an oil absorption value of at least 60 g oil per 100 g of zeolite composition.

A zeolite composition as claimed in claim 5 having an oil absorption of at least 65 g oil per 100 g of the zeolite composition.

A zeolite composition as claimed in claim 6 having an oil absorption of at least 70 g oil per 100 g of the zeolite composition.

A zeolite composition as claimed in claim 5 having an oil absorption of 60 g to 85 g oil per 100 g of the zeolite composition.

A zeolite composition as claimed in claim 8 having an oil absorption of 60 g to 80 g oil per 100 g of the zeolite composition.

10. A zeolite composition as claimed in claim 9 having an oil absorption of 60 g to 75 g oil per 100 g of the zeolite composition.

11 . A particulate, crystalline zeolite composition which comprises particles of co- crystallised zeolite A and zeolite HS, said composition having an oil absorption value of at least 60 g oil per 100 g of the zeolite composition.

A zeolite composition as claimed in claim 1 1 wherein the co-crystallised zeolite A and zeolite HS are in their sodium forms.

13. A zeolite composition as claimed in claim 11 or 12 having an oil absorption of at least 65 g oil per 100 g of the zeolite composition.

14. A zeolite composition as claimed in claim 13 having an oil absorption of at least 70 g oil per 100 g of the zeolite composition.

15. A zeolite composition as claimed in claim 1 1 or 12 having an oil absorption of 60 g to 85 g oil per 100 g of the zeolite composition.

16. A zeolite composition as claimed in claim 15 having an oil absorption of 60 g to 80 g oil per 100 g of the zeolite composition.

17. A zeolite composition as claimed in claim 16 having an oil absorption of 60 g to 75 g oil per 100 g of the zeolite composition.

18. A zeolite composition as claimed in any one of claims 1 to 17 which consists essentially of said particles.

19. A zeolite composition as claimed in any one of claims 1 to 17 which consists of said particles.

A zeolite composition as claimed in any one of claims 1 to 19 wherein said particles consist essentially of co-crystallised zeolite A and zeolite HS in their sodium forms.

A zeolite composition as claimed in any of claims 1 to 19 wherein said particles consist of co-crystallised zeolite A and zeolite HS in their sodium forms.

22. A zeolite composition as claimed in any one of claims 1 to 21 having a particle size distribution such that at least 90% by weight of the particles have a size less than 20 μιη.

23. A zeolite composition as claimed in claim 22 having a particle size distribution such that at least 90% by weight of the particles have a size less than 15 μιη.

24. A zeolite composition as claimed in claim 23 having a particle size distribution such that at least 90% by weight of the particles have a size less than 10 μιη.

25. A zeolite composition as claimed in any one of claims 1 to 24 wherein the zeolite particles have a mean particle size in the range 1 to 10 μιη.

26. A zeolite composition as claimed in claim 25 wherein the zeolite particles have a mean particle size in the range 2 to 8 μιη. method of producing a zeolite composition comprising the steps of: preparing a gel at a temperature above 70 °C from an aqueous admixture of sodium aluminate and sodium silicate having the following composition by mole

(3.5 - 5.5) Na₂0. Al₂0₃. (1 .9 - 2.1 ) Si0_2. (80-95) H₂0, and effecting crystallisation of a zeolite composition from the gel under conditions such that the zeolite composition produced comprises particles of co-crystallised zeolite A and zeolite HS in their sodium forms and has a calcium binding capacity of 20 to 120 mg.CaO/g anhydrous zeolite.

28. A method as claimed in claim 27 wherein said aqueous admixture has the following composition by mole

(3.5 - 5.0) Na₂0. Al₂0₃. (1 .9 - 2.1 ) Si0₂. (80 - 90) H₂0.

29. A method as claimed in claim 27 or 28 wherein the zeolite composition produced is as claimed in any one of claims 1 to 10.

30. A method of producing a zeolite composition comprising the steps of:

(i) preparing a gel at a temperature above 70 °C from an aqueous admixture of sodium aluminate and sodium silicate having the following composition by mole

(3.5 - 5.5) Na₂0. Al₂0₃. (1 .9 - 2.1 ) Si0₂. (80 - 95) H₂0, and

(ii) effecting crystallisation of a zeolite composition from the gel under conditions such that the zeolite composition produced comprises particles of co-crystallised zeolite A and zeolite HS in their sodium forms has an oil absorption value of at least 60g oil per 100g of the zeolite composition.

31 . A method as claimed in claim 30 wherein said aqueous admixture has the following composition by mole

(3.5 - 5.0) Na₂0. Al₂0₃. (1 .9 - 2.1 ) Si0₂. (80 - 90) H₂0.

32. A method as claimed in claim 30 or 31 wherein the zeolite composition produced is as claim in any one of claims 11 to 17.

33. A particulate or granular detergent or detergent additive formulation which comprises crystalline particles of co-crystallised zeolite A and zeolite HS and at least one surfactant absorbed by said particles, wherein the individual zeolite particles free of absorbed material preferably have a size distribution such that at least 90% by weight have a size less than 20 μιη and have a calcium binding capacity of 20 to 120 mg CaO/g anhydrous zeolite.

34. A formulation as claimed in claim 33 wherein the co-crystallised zeolite A and zeolite HS are in their sodium forms.

35. A formulation as claimed in claim 33 or 34 wherein said zeolite particles free of absorbed material comprise a zeolite composition as claimed in any one of claims 1 to 10 or as produced by the method of any one of claims 27 to 29.

36. A particulate or granular detergent or detergent additive formulation which comprises crystalline particles of co-crystallised zeolite A and zeolite HS and at least one surfactant absorbed by said particles, wherein the individual zeolite particles free of absorbed material preferably have a size distribution such that at least 90% by weight have a size less than 20 μιη and have an oil absorption value of at least 60 g of oil per 100 g of the zeolite particles.

37. A formulation as claimed in claim 36 wherein the co-crystallised zeolite A and zeolite HS are in their sodium forms.

38. A formulation as claimed in claim 36 or 37 wherein said zeolite particles free of absorbed material comprise a zeolite composition as claimed in any one of claims 11 to 17 or as produced by the method of any one of claims 30 to 32.

39. A formulation as claimed in any one of claims 33 to 38 which is free-flowing.

40. A formulation as claimed in any one of claims 33 to 39 wherein the surfactant comprises at least one non-ionic surfactant.

41 . A formulation as claimed in claim 40 wherein the non-ionic surfactant comprises at least one ethoxylated long chain alcohol.

42. A formulation as claimed in claim 41 wherein the residue of the alcohol has 12 to 20 carbon atoms.

A formulation as claimed in claim 42 wherein the residue of the alcohol has 12 to 15 carbon atoms.

44. A formulation as claimed in any one of claims 33 to 43 comprising agglomerates of said zeolite particles.

45. A method of producing a particulate or granular detergent or detergent additive formulation comprising admixing relative amounts of a zeolite composition as claimed in any one of claims 1 to 26 and a liquid comprising at least one surface active agent under conditions to produce said particulate or granular detergent additive formulation.

46. A method as claimed in claim 45 wherein said amounts and said conditions produce a free-flowing detergent or detergent additive formulation.

47. A method as claimed in claim 45 or 46 wherein the surfactant comprises at least one non-ionic surfactant.

A method as claimed in claim 47 wherein the non-ionic surfactant comprises at least one ethoxylated long chain alcohol.

A method as claimed in claim 48 wherein the residue of the alcohol has 12 to 20 carbon atoms.

A method as claimed in claim 49 wherein the residue of the alcohol has 12 to 15 carbon atoms.

A method as claimed in any one of claims 45 to 50 wherein said amounts and said conditions produce a detergent or detergent additive formulation comprised of agglomerates of said zeolite particles.

A method of laundry washing comprising dissolving a particulate or granular detergent or detergent additive formulation as claimed in any one of claims 33 to 41 or as produced by the method of any one of claims 45 to 51 in water to produce an aqueous wash solution, and effecting said laundry washing with said aqueous wash solution.