Polymer-containing granulates

Abstract

 A granulate useful in detergent formulations is disclosed, which comprises at least 10% by weight of polymer useful in such formulations and at least 20% by weight of at least one inorganic component which is also useful in such formulations. The granulate has a bulk density of at least 700 g/l, and possesses low hygroscopicity. A process formaking such a granulate is also disclosed.

Description

[0001] This invention is concerned with polymer-containing granules useful as a component for detergent formulations. In the following, "detergent formulations" is intended to encompass cleaning agents for both fabrics and hard surfaces.

[0002] For environmental reasons it has become desirable to reduce or eliminate the phosphate content of detergent formulations. Consequently a replacement component which would provide similar properties, such as inhibition of salt and soil redeposition on washed fabric, and hard surfaces and improved whiteness, must be added. Polymeric additives, especially polycarboxylated polymers, are suitable for this purpose.

[0003] Polymers are generally added to detergent formulations either in the form of a dry powder, formed by spray-drying a solution, dispersion, slurry or emulsion of polymer in a liquid ('wet polymer'), or directly as wet polymer to a detergent formulation in slurry form before drying. In both cases, the final product has a number of undesirable features.

[0004] The dry powder formed by spray-drying wet polymer alone is a material which is hygroscopic and therefore tends to become 'sticky' upon storage or in the final formulation itself. Such dry polymer also has a low bulk density, typically 300-500 g/l, which means that in a typical detergent formulation having density in the region of 700 g/l the polymer has a tendency to separate out; it also reduces the bulk density of the formulation. Furthermore, the dry polymer powder usually has a high proportion of fine material, leading to undesirable dusting problems in the final formulation, and further contributing to the problem of separation.

[0005] One method of adding wet polymer is to add it to other components of the final formulation before drying, and then to spray-dry the polymer and other components together. An example of a granulate composition made by such a method is disclosed in DE-A-3316513, in which a granule for use as a phosphate substitute, containing 30-75% zeolite together with at least 5% polycarboxylate, is made by spray-drying a slurry of the components. Such a spray-drying process invariably yields a granulated product of undesirably low density, and indeed the highest density achieved by this composition is 610 g/l; also, additional water - that introduced with the polymer - has to be removed.

[0006] An alternative method for adding wet polymer is to add it directly to the final formulation as it is mixed and dried in a rotating drum mixer. However wet polymer contains liquid (usually water) and polymer in a ratio of about 1:1, so that adding more than just a few percent of polymer requires the addition of a significant amount of liquid also: solubilization by the liquid of other components in the formulation tends to result in the formulation of a paste in the dryer. This problem cannot be avoided by reducing the liquid content of the polymer prior to addition, because the viscosity of the wet polymer becomes too high for satisfactory flowability and even distribution of the polymer amongst the other components.

[0007] The above method of adding wet polymer may be used when polymers are to be employed as agglomerating agents for salts; in such a case they are added at concentrations of only about 0.5%, so that the difficulties with excess liquid become insignificant.

[0008] The above problems also cannot be avoided by adding the polymer to solutions of other salts to be used in the final formulation such as sulphates and carbonates, and then drying by evaporation, because the polymers used are effective crystallization inhibitors for those salts.

[0009] In summary therefore, forms of dry polymer hitherto produced have proved unsatisfactory for detergent formulations in that (i) the polymer dried alone has particle size, hygroscopicity and density disadvantages and (ii) the polymer dried in the presence of the remainder of the formulation induces paste formation if dried in spray-mixing equipment or reduces to too low a density if dried in a spray tower. There was no indication, indeed the experience in (ii) contraindicated, that the polymer could be successfully combined with some of the other components for the detergent formulation into a granular form, having desirable particle size and bulk density, for addition to the detergent formulation.

[0010] A high density polymer-containing granulate is known, from EP-A-368137; it contains 60-80% zeolite, 2-15% polycarboxylate, and 14-25% by weight of water, and has a density of 750-1000 g/l. However, the presence of such a large proportion of water-insoluble zeolite brings disadvantages. Water-insoluble salts have a tendency to deposit on fabrics, a problem which the addition of polymers is at least partly intended to counteract; in a granule containing such a high ratio of water-insoluble salt to polymer, any effect as a suspending agent which the polymer might have been intended to have would be virtually nullified by the large amount of zeolite introduced with the polymer.

[0011] A granular detergent additive is known from US-A-46981 74 which comprises 20-80% polymer, 20-80% nitrilotriacetic acid (NTA) and optionally up to 20% of another additive such as sodium sulphate. Densities of up to 690 g/l are disclosed, and the product is also said to have low hygroscopicity. However, the usefulness of this additive is limited by the necessity for it to comprise a significant proportion of NTA to obtain satisfactory performance; large proportions of NTA may be considered undesirable on environmental grounds. Furthermore the densities disclosed are still generally less than the average density of a typical detergent.

[0012] In a first aspect the present invention provides a composition, useful as a component of a detergent formulation, in the form of granules each comprising at least 10% by weight of polymer useful in such formulations and at least 20% by weight of at least one water-soluble inorganic component also useful in such formulations, the bulk density of said composition being at least 700 g/l. Preferred inorganic components are salts, such as sulphates, carbonates and silicates. Perborates (both mono- and tetrahydrate), percarbonates and persulphates may also be useful. In formulations where phosphates are still present, they may also be used as carriers. For all the above salts, the sodium form is preferred.

[0013] The present invention is also applicable to the case where the inorganic component is zeolite or clay, which are both water-insoluble. In such a case, a greater proportion of polymer is necessary in order to counteract the tendency of the water-insoluble component to deposit on fabrics, as indicated above. Accordingly in a second aspect the present invention provides a composition, useful as a component in detergent formulations, in the form of granules each comprising at least 20% by weight of polymer useful in such formulations and at least 20% by weight of zeolite, the bulk of density of said composition being at least 700 g/l.

[0014] It will be appreciated that in both cases the granules may contain minor amounts of other components which are suitable for use in detergent compositions.

[0015] The density of the granulate may be as low as 300 g/l or as high as 1400 g/l, although a density in the range from 700 to 1200 g/l is preferred, particularly over 900 g/l. The density depends on the type of inorganic component ("carrier"), on polymer type, and on manufacturing process conditions and equipment (discussed hereinafter), and also on the relative proportions of polymer(s) and carrier(s). Thus granules containing up to 80% polymer by weight may be prepared. In this case, the density of such granules will be at the bottom end of the desired range. Typically 10% to 50% by weight polymer is present in the granule (but at least 20%, preferably at least 25% where zeolite is present) , and more typically from 20% to 40%. The most preferred amount of polymer is 30%.

[0016] Suitable polymers include homopolymers or copolymers of dicarboxylic acids such as maleic acid, itaconic acid, mesaconic acid, fumaric acid, citraconic acid and the anhydrides of ds dicarboxylic acids, such as maleic anhydride; monocarboxylic acids such as acrylic acid, methacrylic acid, vinyl acetic acid, crotonic acid and acryloxypropionic acid; and unsaturated non-carboxylic aceds such as alkyl esters of acrylic or methacrylic acids such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and isobutyl methacrylate; hydroxyalkyl esters of acrylic or methacrylic acids such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate (including polyethoxylated esters); acrylamide, methacrylamide, N-tertiary butyl acrylamide, N-methyl acrylamide, N,N-dimethyl acrylamide; acrylonitrile, methacrylonitrile, allyl alcohol, allyl sulfonic acid, allyl phosphonic acid, vinylphosphonic acid, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, phosphoethyl methacrylate, N-vinyl pyrrolidone, N-vinylformamide, N-vinylimidazole, ethylene glycol diacrylate, trimethylolpropane triacrylate, diallyl phthalate, vinyl acetate, styrene, vinyl sulfonic acid and its salts, and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and its salts. Monomers of 1-olefins, such as diisobutylene and 1-octene, are also suitable, as is the polymer "POC" (the reaction product of acrylic acid and peroxodisulphate).

[0017] Polymers can be in acid or neutralized or partially neutralized form with Na, K, NH₄ or other counterions. Molecular weights of the polymers may be from 500 to 5,000,000. Generally the higher molecular weight, the greater the degree of agglomeration obtained during manufacture of the granules and hence the larger the granules. Thus the choice of molecular weight will be at least partly dependent on the granulometry of the product required.

[0018] Examples of polymers employed in the present invention are an acrylic acid homo-polymer having a weight-average molecular weight of 4500 and an acrylic/maleic copolymer having a weight-average molecular weight of about 70,000.

[0019] The granules of the present invention can have a wide range of size distributions, from 1 micron to 2mm or more in diameter. Granulates with up to 80-% particles on 14 U.S. mesh (mesh size 1.18 mm) or with up to 80% particles through 100 U.S. mesh (mesh size 0.15 mm) can be produced. It is preferred that less than 50% by weight pass through 100 U.S. mesh. In a preferred option, the size of the granules formed is such that it approximates to the average size of particles in a standard detergent composition (0.2-­0.4mm typically).

[0020] The granular composition of the invention provides polymer suitable for use in detergent formulations in a form which has considerable advantages over the prior art. The dry granule may be added direct to the final formulation, thereby circumventing all the disadvantages associated with wet polymer. The composition can be adjusted to have a granulometry and density very similar to that of the other components in the final formulation, thereby avoiding the problems of separation and dusting associated with spray-dried polymer. Furthermore, the granular composition of the present invention does not suffer from the problems of hygroscopicity which affects spray-dried polymer. The larger particulate size means that there is less surface area per unit weight to absorb moisture, and also the proportion of hygroscopic polymer in each granule is obviously less than in 'dry polymer' powder. For the purposes of the present invention, a granulate which absorbs less than 20% of its own weight in water when exposed to moisture is preferred, particularly less than 10%. The method employed to determine this percentage of water absorption is as follows:

[0021] A previously weighed container is placed in an air-conditioned room at a temperature of 20°C and humidity of 50%, filled with a thin layer (5-20mm) of polymer and immediately reweighed, at which point the test starts. The container and polymer are then reweighed at ten minute intervals during the first hour, 30 minute intervals during the second hour, hourly during the next five hours and then every 24 hours. The percentage increase in weight gives the amount of water absorbed, and the figure quoted is that attained when a steady state has been reached.

[0022] Thus the present invention has successfully solved the problem of obtaining polymer in a form which is acceptable for direct addition to detergent formulations, without the attendant problems either of the liquid carrier associated with the polymer, or of the consequences of having removed that liquid carrier first. Furthermore, the present invention provides a much more flexible solution to the previous problems than known compositions such as those described hereinabove, in that there is a wide variety of inorganic components which can be incorporated with the polymer, with no individual compound being an essential prerequisite. Additionally, the density of the composition of the invention can be significantly higher than that possible with known compositions.

[0023] The present invention also provides, in further aspect, a detergent formulation containing polymer in the form of a composition as defined above; and in a still further aspect it comprises the use of a composition as defined above as a component in a detergent formulation. The proportion of the granulate composition of this invention required in a typical detergent formulation will generally be such as to give an active polymer content in the formulation of from 0.1 to 20% by weight, more usually between 1 and 5%.

[0024] Typical detergents for which the granular composition of the present invention may be suitable are usually based on surfactants and, optionally, on either precipitant or sequestrant builders. Suitable surfactants are, for example, anionic surfactants, such as (C₈ to C₁₂) alkylbenzenesulfonates, (C₁₂ to C₁₆) alkane sulfonates, (C₁₂ to C₁₆) alkylsulfates, (C₁₂ to C₁₆) alkylsulfosuccinates and (C₁₂ to C₁₆) sulfated ethoxylated alkanols. Nonionic surfactants may be (C₆ to C₁₂) alkylphenol ethoxylates, (C₁₂ to C₂₀) alkanol alkoxylates, and block copolymers of ethylene oxide and propylene oxide. Optionally, the end groups of polyalkylene oxides can be blocked. This means the free OH groups of the polyalkylene oxides can be etherified, esterified, acetalised and/or aminated. Another modification consists of reacting the free -OH groups of the polyalkylene oxides with isocyanates.

[0025] Nonionic surfactants may also include (C₄ to C₁₈) alkyl glucosides as well as the alkoxylated products obtainable therefrom by alkoxylation, particularly those obtainable by reaction of alkyl glucosides with ethylene oxide. Surfactants useful in detergents can also have an amphoteric character and they can be soaps. In general, the surfactants constitute from 2 to 50 wt % of a detergent.

[0026] Sequestrant builders contained in detergents have generally been phosphates, orthophosphates, pyrophosphates or especially sodium tripolyphosphate. However, because of the severe environmental pollution caused by the use of phosphates, the phosphate content of detergents and cleaning agents is increasingly being reduced so that detergents currently contain up to 25% of phosphates or preferably are phosphate-free. As discussed previously, the composition of the present invention is primarily of value as a means for introducing into the detergent a partial or complete replacement for phosphates, comprising polymers as previously listed. Other builders include zeolites, sodium carbonate, nitrilotriacetic acid, citric acid, tartaric acid, the salts of the aforesaid acids and the monomeric, oligomeric or polymeric phosphonates. Varying amounts of the individual substances are used in the preparation of detergent formulations. For example, sodium carbonate may be used in an amount of up to 80%, phosphates up to 80%, zeolites up to 40%, nitrilotriacetic acid and phosphonates up to 10% and polycarboxylic acids in an amount of up to 30% by weight based on the total detergent formulation.

[0027] Typical detergent formulations optionally also contain corrosion inhibitors, such as silicates as additional additives. Suitable silicates are, for example, sodium silicate, sodium disilicate and sodium metasilicate. The corrosion inhibitors can constitute up to 50 wt % of the detergent formulation. Other common additives to detergent and cleaning agent formulations are bleaching agents used in an amount of up to 30 wt %. Suitable bleaching agents are for example, perborates, percarbonates, or chlorine-generating substances, such as chloroisocyanurates. Another group of additives that can be used in detergents are greying inhibitors. Known substances of this type are carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose and graft copolymers of vinyl acetate and polyalkylene oxides having a molecular weight of 1000 to 15,000. Greying inhibitors are used in the detergent formulations in an amount of up to 5%. Other common detergent additives that can optionally be used are optical brighteners, enzymes and perfume. Powdered detergent formulations can also contain up to 50 wt % of a diluent, such as sodium sulfate. The detergent formulations can be anhydrous or they can obtain small amounts, for example up to 10 wt %, of water.

[0028] The composition of the present invention may be made by a process according to a further aspect of the invention, which comprises mixing polymer useful in detergent compositions with a liquid suitable for carrying or solubilizing said polymer and at least one solid inorganic component, the ratio of polymer to inorganic component being from 1:9 to 5:1, and subjecting the mixture to conditions of agitation and heat such that granules are formed. Generally the polymer and liquid are introduced together - as a slurry, solution, emulsion, suspension or dispersion of polymer in liquid. Preferably the granules formed are as defined hereinabove.

[0029] The particular conditions of heat and agitation which are required in order to produce the desired granules are complex, and dependent on a large number of interrelated variables. It is highly important that the polymer, liquid and inorganic component are subjected to a degree of turbulence such that rapid and intimate mixing, plus uniform heating is achieved; additionally a rapid and effective rate of heat transfer is required in order to evaporate the liquid very soon after the mixture is formed, especially when the inorganic component is soluble in the liquid.

[0030] In a preferred embodiment of the process which achieves the above requirements, the components are mixed in a horizontal cylindrical chamber having an axial shaft which carries a series of radial blades extending almost to the wall of the chamber, which forces the mixture into a highly turbulent thin layer around the wall of the chamber. A pressure differential moves the mixture along the chamber, where it is additionally subjected to heating by one or both of hot air blown through the chamber and heating of the chamber wall in contact with the mixture layer. The mixture may be subjected to heating as soon as it enters the chamber; alternatively, heat may be applied after the mixture has passed a little way along the chamber, so that initial mixing occurs before the commencement of evaporation. This alternative procedure may also be embodied by employing two chambers, in series, the first of which subjects the mixture solely to high agitation and the second of which subjects it both to agitation and to heating. This method allows greater control of the degree of turbulence at each stage, although, for reasons outlined above, care may be needed in determining the residence time in the initial mixing chamber to ensure that evaporation does not commence too late.

[0031] Although the chamber(s) is preferably horizontal, this is not essential and it may be inclined or even vertical.

[0032] The unique combination of turbulence and rate of heat transfer provided by the process of this invention results in a product which was not previously achievable. The granules produced are generally an agglomeration of many particles, each particle comprising a core of inorganic component ('carrier') coated with a layer of polymer, although under certain conditions a homogeneous mixture may be formed. The process of the invention is particularly advantageous in the case where the inorganic component is soluble in the liquid (usually water) carrying the polymer. An example is where the inorganic component is a sulphate, which is soluble in water. In such a case, the evaporation of the liquid in this process is so rapid that solubilization of the inorganic carrier occurs only to an extent which is insufficient to deleteriously affect the density or particle size of the final granulate product. This would be impossible with conventional techniques.

[0033] As mentioned above, the parameters influencing the nature of the final product are many and complex. The relative proportions of polymer and carrier are significant; increasing the proportion of polymer reduces the density of the final granules, and also results in larger granules by causing more agglomeration. The nature of the components is also significant. As discussed previously, the molecular weight of the polymer can influence the granulometry of the final product. It can be advantageous for the inorganic component to be an anhydrous salt, since this will absorb water carrying the polymer during mixing, thereby leaving less to be evaporated and speeding the process. The two main process conditions which need to be influenced are the rate of heat transfer to the components as they are being mixed, and the degree of turbulence of that mixing. As a generalisation, increasing either the rate of heat transfer or the turbulence reduces the degree of agglomeration, and hence the size of the particles.

[0034] The rate of heat transfer may be enhanced by increasing either the temperature or the flowrate of the hot air which is passed through the chamber, or by increasing the temperature of the heating jacket around the wall of the chamber. As discussed previously, the positions of the hot air inlet and the heating jacket may also be adjusted to influence the timing and rate of heat transfer. The initial temperature of the liquid carrying the polymer may also be varied; increasing this not only improves the evaporation capacity of the apparatus, but also the homogeneity of the final granule by reducing the initial viscosity of the liquid/polymer system. The rate of heat transfer is also increased by greater turbulence.

[0035] The turbulence of the mixture in the chamber may be increased by increasing the speed of rotation of the shaft and blades. It is also influenced by the nature of the blades - their number, shape, orientation, etc; it will be appreciated that the precise effect of the blades is a matter for assessment in each case.

[0036] Another factor of significance is the residence time of the mixture in the chamber - i.e. the length of time of its exposure to heating and/or turbulent mixing, which has to be adjusted to provide the optimum balance. The mixture is drawn through the chamber largely by a pressure differential, variation of which will of course alter the residence time. The length of the chamber - or separation into a mixing and a mixing/heating chamber - is another influencing factor.

[0037] Preferred embodiments of both the process and the composition of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic representation of an agglomerating apparatus suitable for performing a preferred process of the invention;

Figures 2 to 4 are graphs showing the granulometry of compositions of the invention.

[0038] Referring to Figure 1, preferred apparatus for the agglomeration process of the invention comprises a horizontal cylindrical chamber 2 having at one end inlets 4,6 for the liquid/polymer system and dry inorganic carrier respectively, and at its other end an outlet 8 for the granulated product. An air compressor 22 pushes the air (and hence the material) along the chamber, and a fan 10 contributes to a pressure drop which also helps to draw the material through.

[0039] Heating is accomplished partly by hot air injected into the chamber through inlet 12, and partly by a coaxial heating jacket 14 around the chamber. Hot air inlet 12 and jacket 14 are spaced along the chamber from the raw material inlets 4,6 so that material in the initial portion of the chamber is not subjected to heating, but only to mixing. As discussed previously, in an alternative embodiment this initial mixing without heating phase (which is not always essential) may be performed in a separate chamber.

[0040] Turbulent mixing is accomplished by means of a rapidly rotating axial shaft 16 which carries a series of blades 18 each extending radially towards the wall of the chamber. In this embodiment each blade is substantially rectangular, and its outer edge is spaced from the internal wall of the chamber 2 by a few millimetres (this spacing being adjustable). Shaft 16 is driven by a motor 20. In certain embodiments movement of the material along the chamber may be accomplished solely by the rotating blades, without the need for a pressure differential.

[0041] The operation of the apparatus of Figure 1 is as follows, described with reference to a preferred composition comprising a polymer/water system.

[0042] Dry carrier and a solution of polymer in water enter the chamber 2 through respective inlets 4,6. The polymer solution may already be at elevated temperature in order to reduce its viscosity and improve mixing. Inside the chamber the shaft 16 and its blades 18 are rotated at a high rate, typically from 500 to 3000 rpm. The rate employed depends of course on factors such as the diameter of the drum, since the important parameter is the tangential velocity imparted to the mixture at the surface of the chamber wall (in this particular embodiment the tangential velocity is generally from 10 to 30 ms-¹).

[0043] The mixture of polymer, water and carrier is drawn through the chamber by the combined action of compressor 22 and fan 10, whilst the centrifugal force created by the rapdily rotating blades 18 forces the mixture into a highly dynamic suspension in the form of a thin layer around the internal surface of the chamber wall. The precise thickness of the layer depends on a number of factors, particularly the degree of centrifugal force exerted on it, but it is approximately 1-2 mm. The blades are preferably arranged to extend close enough to the chamber wall that their outer edges contact and disrupt the layer of agglomerating mixture, thereby generating further turbulence and inhibiting the development of excessively large granules.

[0044] The residence time of the mixture in the initial unheated portion of the chamber is very short - of the order of a few seconds. It is especially important if the carrier is soluble in water that the carrier does not begin to dissolve before evaporation of the water begins. Of course, if necessary the apparatus may be arranged so that the mixture is subjected to heating as soon as it enters the mixing chamber.

[0045] Alter this initial mixing phase, the mixture is subjected to heating by hot air injected through inlet 12 and saturated steam passing around jacket 14. Together these provide a very efficient combination of both convective and conductive heat transfer, resulting in rapid evaporation of the water from the mixture. The continuous rotation of the mixture layer and individual particles within it provides ideal conditions of turbulence and particle separation, permitting uniform heating and excellent agglomeration.

[0046] The mixture reaches outlet 8 after a time period of from around 10 seconds to a few minutes, by which time it has agglomerated into dense, dry granules of polymer and carrier, with the water being removed as vapour.

[0047] Specific examples of granulated compositions of the present invention produced by the above exemplified process are as follows:

Example 1:

[0048] A granulate containing 30% dry polymer is obtained as follows: 100 kg/h of sodium sulphate and 95 kg/h of a 45% water solution of an acrylic acid homopolymer having a weight average molecular weight of 4500 are fed continuously into the mixer chamber.

[0049] The shaft speed rotation is 900 rpm, the hot air is fed (co-currently with the granule flow) into the mixing chamber at 225°C and 280 m³/h. Saturated steam at 160°C is fed into the jacket.

[0050] Finished product (granulates) is discharged continuously starting about one minute after the operation start-up, at 143 kg/h, 0,5% residual moisture and 100°C. The density of the product is 1000 g/lt and the granulometry spectrum, compared with leading fabric wash detergents, is shown in Figure 2.

Example 2:

[0051] A product containing 10% dry polymer is obtained by employing the same process conditions as Example 1, but with 100 kg/h of sodium sulphate and 28 kg/h of an acrylic/maleic copolymer having a weight average molecular weight of 70,000.

[0052] Density of the granulates is 1200 g/lt, and the granulometry distribution is shown in Figure 3.

Example 3:

[0053] A product containing 30% dry polymer is obtained as follows: 120 kg/h of sodium carbonate and 115 kg/h of the polymer of Example 1 are fed continuously into the mixing chamber. The shaft speed rotation is 1800 rpm, the hot air is fed co-currently at 200°C. Saturated steam at 180°C is fed into the jacket. Finished product is obtained at 1% residual moisture at 70°C. The density of the product is 860 g/lt and the granulometry spectrum is shown in Figure 4.

Claims

1. Granules, useful as a component in detergent formulations, each comprising at least 10% by weight of polymer useful in such formulations and at least 20% by weight of at least one water-soluble inorganic component also useful in such formulations, the bulk density of said composition being at least 700 g/l.

2. Granules according to Claim 1, wherein said inorganic component is one or more of sulphate, carbonate, phosphate, silicate, percarbonate or perborate, preferably sulphate or carbonate.

3. Granules, useful as a component in detergent formulations, each comprising at least 20% by weight of polymer useful in such formulations and at least 20% by weight of zeolite and for clay, the bulk density of said composition being at least 700 g/l.

4. Granules according to any preceding Claim, having a bulk density of at least 900 g/l.

5. Granules according to any preceding Claim, wherein said polymer is polycarboxylated polymer, preferably a homopolymer or copolymer of one or more of acrylic acid, methacrylic acid, maleic acid, acrylamide, itaconic acid, (C₁-C₄)-alkyl (meth)acrylates or amides, alpha-chloroacrylic acid, alkylvinyl­ether or vinylesters.

6. Granules according to any preceding Claim wherein the proportion of polymer is from 20 to 40%, preferably 30%.

7. Granules according to any preceding Claim wherein the granule size is such that less than 50% by weight passes through 100 US mesh (mesh size 0.15 mm).

8. Granules according to any preceding Claim which absorbs less than 20%, preferably less than 10%, of its weight in water when exposed to moisture, tested according to the method hereinbefore described.

9. The use of granules according to any preceding Claim as a component in a detergent formulation.

10. A detergent formulation containing polymer in the form of granules according to any of claims 1 to 8.

11. A process for making a polymer-containing component useful in a detergent formulation comprising mixing polymer useful in detergent formulations with a liquid suitable for carrying or solubilizing said polymer and at least one solid inorganic component itself useful in detergent formulations, wherein the ratio of polymer to inorganic component is from 1:9 to 5:1, and subjecting the mixture to conditions of agitation and heat such that granules are formed.

12. Process according to claim 11, wherein the mixture is introduced into a cylindrical chamber (2) containing a rapidly rotating axial shaft (16) carrying a series of blades (18), and heat applied to the mixture along at least a part of the length of said chamber.

13. Process according to claim 12, wherein the mixture is initially introduced into a first cylindrical chamber also containing a rapidly rotating axial shaft carrying a series of blades, in which chamber no heating takes place.

14. Process according to claim 12 or 13, wherein said heat is applied by one or both of hot air injected into said chamber (2) and heating of the internal surface of said chamber.

15. Process according to any one of claims 11 to 14 wherein said inorganic component is zeolite, clay or as defined in claim 2, and said polymer is as defined in claim 5.

16. Process according to any one of claims 11 to 15 wherein said liquid is water.

Drawing