Patent Description:
Particulate mineral compositions have been developed to provide certain characteristics to polymers. For example, talc particulates have been developed to provide stiffness in plastics, or barrier performance in rubber. Exemplary talc particulates are described in <CIT>. These days, they are for instance used in polypropylene based formulations with talc contents ranging from about <NUM> to <NUM> wt. -%, based on the total content of the formulation.

For example, talcs may be used as functional fillers in polymer compositions, for example, to modify, enhance or modulate one or more electrical, physical, mechanical, thermal or optical properties of the functional compositions. Talcs may also be used as extender fillers, for example in inks or paints. For example, as plastic compounders, talc fillers provide stiffness, temperature resistance and dimensional stability.

Particulate wollastonites have also been employed as additives in paints and plastics. In plastics, wollastonite improves tensile and flexural strength, reduces resin consumption, and improves thermal and dimensional stability at elevated temperatures.

For high performance plastics, talc and/or wollastonite fillers employed are normally very fine. The bulk density and tapped density of these finely divided products is low, limiting their use, since this makes transport and handling difficult and economically challenging. In order to overcome these problems, compacted or deaerated particulate mineral compositions are generally offered on the market. Compacting is normally carried out using pelletisation presses, in the presence of water. Lower water content leads to higher bulk density, but lower dispersability for the end user. A compromise between these required properties must normally be found.

Ultrafine talc powder has a bulk density of about <NUM> to <NUM>/cm<NUM>. Compacted ultrafine talc powder normally has a tapped density of about <NUM> to <NUM>/cm<NUM>. Higher bulk densities, or tapped densities, will be required as demand for compacted particulate minerals is expected to rise in the future.

<CIT> discloses talc containing compositions for use in thermoplastic materials, comprising talc, polyethylene wax and a surface active agent, such as amines, quaternary ammonium salts, quaternary polyammonium salts or carboxylic acids. The lower the amount of polyethylene wax in the composition is, the more surface active agent needs to be added in order to obtain satisfactory results. Overall, the granulated compressed talc compositions maintain a relatively low talc content of <NUM> wt. -% or less. Resin composition comprising an inorganic filler are also disclosed in <CIT> and <CIT>.

The prior art therefore represents a problem.

In particular, the present invention is embodied by a composition comprising from <NUM> to <NUM> wt. -% organic binder, from <NUM> to <NUM> wt. -% water; and <NUM> to <NUM> wt. -% inorganic particulate material selected from talc, wollastonite or a mixture thereof, wherein the composition is a compressed granulated composition, such as brick, a briquette, a pellet, a pressing, a mould, a preform, a spray-dried powder, a tablet, an aggregate, a rod, a granulate, or an agglomerate, or any mixture thereof, wherein the wt. -% indicated is expressed compared to the total content non-aqueous components in the said composition, further wherein the said organic binder is selected from stearic acid or its salts, paraffin, glycerol monostearate, polyethylene glycol, ethylene-vinyl acetate (EVA) and mixtures thereof. It was found that compressed compositions with a high talc content and high bulk density and tapped density could be obtained.

The said organic binder is selected from stearic acid or its salts, paraffin, glycerol monostearate, polyethylene glycol, ethylene-vinyl acetate (EVA) and mixtures thereof. For example, the stearic acid salts may be selected from magnesium stearate, or zinc stearate. It was found that these organic binders were particularly suitable for use in the present invention.

According to one embodiment, the talc may be selected from micronized talc, bimodal talc, and cationic talc. It was found that the invention is applicable to all these types of talc.

According to one embodiment, the composition may be an essentially dry composition. For example, the water content may be <NUM> wt. -% or less. It was found that the compositions according to the present invention may suitably be used as dry compositions, without any detrimental effects.

According to one further embodiment, the talc and/or wollastonite particles that form part of the inorganic particulate material in the composition according to the invention may have a D<NUM> in the range of <NUM> to <NUM>, and/or a D<NUM> in the range of <NUM> to <NUM>. For example, the talc particles that for part of the inorganic particulate material in the composition according to the invention may have a D<NUM> in the range of <NUM> to <NUM> and/or a D<NUM> in the range of <NUM> to <NUM>. For example, the talc particles that for part of the inorganic particulate material in the composition according to the invention may have a D<NUM> in the range of <NUM> to <NUM> and/or a D<NUM> in the range of <NUM> to <NUM>. It was found that the present invention was particularly suitable for compaction of particulate materials of these particle sizes.

According to one further embodiment, the compressed granulated composition has a tapped density in accordance with ISO <NUM>/<NUM> of <NUM> to <NUM>/cm<NUM>. Higher densities lead to better efficiency on storage, transport and handling of the compositions.

Also part of the present invention is a method for producing a compressed granulated composition of the invention, comprising the steps of compounding an organic binder, optionally water, and a particulate inorganic material in a mixing tank, followed by pelletising the obtained mixture. It was found that when the above mentioned components are used, standard pelletising techniques known to the skilled person in the art may be employed.

According to one embodiment, the method comprises an additional step of drying the mixture either prior to or after pelletisation by heating. It was found that a removal of water, if required, may be carried out at any time of the production process.

According to one embodiment, the method comprises an additional step of heating the organic binder prior to admixing with the water and the particulate material. Heating the said organic binder may help mixing of the components in the admixing step.

According to one further embodiment of the present invention, in the method, the organic binder is pre-mixed with water prior to admixture to the said particulate material, optionally wherein a surface agent is added to the mixture of organic binder and water. It was found that pre-mixing of the organic binder with water may improve the easy mixing of the components. Furthermore, the addition of a surface agent may help preparing the admixture.

Also part of the present invention is the use of the compressed granulated compositions of the invention as a filler in a polymeric composition, as is the filled polymeric composition comprising the composition of the present invention, or a derivate thereof. In accordance with the present invention, the compressed granulated compositions present certain advantages when used as fillers in polymeric compositions, such as improved handling and transport.

It is understood that the following description and references concern exemplary embodiments of the present invention and shall not be limiting the scope of the claims.

The present invention according to the appended claims provides compositions comprising particulate talc and/or wollastonite. The compositions may be in the shape of compressed compositions, such as tablets, pellets, granulates, aggregates, bricks, briquettes, pressings, moulds, preforms, spray-dried powders, rods, or any mixtures thereof.

Inorganic particulates have been used as fillers in polymeric compositions for a long time. Talc and wollastonite are particularly popular as fillers. The fillers are generally provided in dry form to the end user. As such, it is advantageous to compress the inorganic particulate matter into pellets or other compressed forms, in order to simplify handling and avoid dust formation. It is advantageous to provide compressed inorganic particulate matters having (i) a high weight content of the active ingredient, in this case talc and/or wollastonite, and (ii) a high bulk density and tapped density, in order to limit the volume occupied by the compressed particulate matter. It is further preferred than upon end-use, the compressed particulate matter has good dispersability in the polymeric composition, in other words, deagglomeration of the compressed form should be easy and efficient to obtain.

Natural minerals are not found in pure form. As used herein, the term "talc" means either the magnesium silicate mineral, or the mineral chlorite (magnesium aluminium silicate), or a mixture of the two, optionally associated with other minerals, for example, dolomite and/or magnesite, or furthermore, synthetic talc, also known as talcose.

As used herein, the term "wollastonite" means either calcium inosilicate mineral (CaSiO3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. It may also contain associated minerals such as garnets, vesuvianite, diopside, tremolite, epidote, plagioclase feldspar, pyroxene and calcite.

The present invention is based on the use of organic binders to provide compressed particulate talc and/or wollastonite. It was found that particularly high concentrations of talc and/or wollastonite can be obtained when <NUM> to <NUM> wt. -% organic binder are employed, based on the total weight of the non-aqueous components in the composition. A particular advantage is that the use of the organic binder may be employed in the presence or in the absence of water. The compressed particulate material may then be dried after compaction. Finally, the use of the mentioned amounts of organic binder lead to ideal compromise of compaction on the one hand and dispersability and mechanical performance on the other hand.

The organic binder may be present in an amount of <NUM> wt. -% to <NUM> wt. -% based on the total amount of the non-aqueous components in the composition material. For example, the composition according to the present invention comprises about <NUM> wt. -% organic binder, or about <NUM> wt. -% organic binder, or about <NUM> wt. -% organic binder, or about <NUM> wt. -% organic binder, or about <NUM> wt. -% organic binder, or about <NUM> wt. -% organic binder, or about <NUM> wt. -% organic binder, or from <NUM> wt. -% to <NUM> wt. -% organic binder, or from <NUM> wt. -% to <NUM> wt. -% organic binder, or from <NUM> wt. -% to <NUM> wt. -% organic binder, or from <NUM> wt. -% to <NUM> wt. -% organic binder, or from <NUM> wt. -% to <NUM> wt. -% organic binder, based on the total amount of non-aqueous components.

The organic binder employed is selected from stearic acid or its salts, paraffin, glycerol monostearate, polyethylene glycol, ethylene-vinyl acetate (EVA) and mixtures thereof. For example, if the organic binder is a stearic acid salt, it may be magnesium stearate, or zinc stearate, or a mixture thereof.

Water may be comprised in the composition according to the present invention by up to <NUM> wt. -%, based on the total amount of non-aqueous components. For example, the compressed composition may comprise about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, or about <NUM> wt. -% water, based on the total weight of non-aqueous material. For example, the composition according to the present invention may comprise from <NUM> wt. -% to <NUM> wt. -% water, or from <NUM> wt. -% to <NUM> wt. -% water, or from <NUM> wt. -% to <NUM> wt. -% water, or from <NUM> wt. -% to <NUM> wt. -% water, or from <NUM> wt. -% to <NUM> wt. -% water, or from <NUM> wt. -% to <NUM> wt. -% water, or from <NUM> wt. -% to <NUM> wt. -% water, based on the total amount of non-aqueous components in the composition.

In other embodiments, the composition according to the present invention may be essentially free of water. For example the composition may comprise water in amount that is no longer detectable by ordinary means, or the composition may comprise less than <NUM> wt. -% water, or less than <NUM> wt. -% or less than <NUM> wt. -% water, based on the total amount of non-aqueous components in the composition.

Water may be added in order to ease compaction of the particulate inorganic material in the presence of organic binder, and may subsequently be removed, or not, depending on the requirements of the end material.

The present invention concerns the provision of compressed compositions of particulate inorganic material selected from talc and/or wollastonite. According to the present invention, the composition may comprise any relative proportion of talc and wollastonite. For example, the inorganic particulate material may consist of or essentially consist of talc, or the inorganic particulate material may consist of or essentially consist of wollastonite. In other embodiments, the inorganic particulate may be a <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or an about <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or a <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or an about <NUM>:<NUM> (by weight) mixture of talc and wollastonite a <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or an about <NUM>:<NUM> (by weight) mixture of talc and wollastonite a <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or an about <NUM>:<NUM> (by weight) mixture of talc and wollastonite a <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or an about <NUM>:<NUM> (by weight) mixture of talc and wollastonite a <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or an about <NUM>:<NUM> (by weight) mixture of talc and wollastonite a <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or an about <NUM>:<NUM> (by weight) mixture of talc and wollastonite a <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or an about <NUM>:<NUM> (by weight) mixture of talc and wollastonite a <NUM>:<NUM> (by weight) mixture of talc and wollastonite, or an about <NUM>:<NUM> (by weight) mixture of talc and wollastonite.

In accordance with the present invention, the amount of talc and/or wollastonite may be from <NUM> to <NUM> wt. -%, based on the total amount of non-aqueous components in the composition. For example, the amount of talc and/or wollastonite may be about <NUM> wt. -%, or about <NUM> wt. -%, or about <NUM> wt. -%, or about <NUM> wt. -%, or about <NUM> wt. -%, or about <NUM> wt. -%, or about <NUM> wt. -%, or about <NUM> wt. -%, or about <NUM> wt. -%, or about <NUM> wt. -%, or from <NUM> wt. -% to <NUM> wt. -%, or from <NUM> wt. -% to <NUM> wt. -%, or from <NUM> wt. -% to <NUM> wt. -%, or from <NUM> wt. -% to <NUM> wt.

As can be seen, the composition according to the present invention comprises from <NUM> wt. -% to <NUM> wt. -% organic binder and from <NUM> wt. -% to <NUM> wt. -% inorganic particulate matter, based on the total amount of non-aqueous components in the composition. The rest (up to <NUM> wt. -%) may be made up by surface active agents and/or impurities. However, the composition according to the present invention may also comprise essentially <NUM> wt. -% organic binder and inorganic particulate matter, based on all the non-aqueous materials.

In accordance with one embodiment of the present invention, the talc may be a micronized talc. In accordance with one embodiment of the present invention, the talc may have a monomodal particle size distribution, or the talc may have a polymodal particle size distribution, such as for example a bimodal particle size distribution. In accordance with one embodiment of the present invention, the talc may be a cationic talc.

Similarly, in accordance with the present invention, the wollastonite may be present as a finely divided wollastonite. In accordance with one embodiment of the present invention, the wollastonite may have a monomodal particle size distribution, or the wollastonite may have a polymodal particle size distribution, such as for example a bimodal particle size distribution.

In accordance with the present invention, the talc may have a median particle size (D<NUM>) in the range of <NUM> to <NUM>, for example the D<NUM> of the talc may be about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>.

In accordance with the present invention, the talc may have a D<NUM> particle size in the range of <NUM> to <NUM>, for example the D<NUM> of the talc may be about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>.

In accordance with the present invention, the wollastonite may have a median particle size (D<NUM>) in the range of <NUM> to <NUM>, for example the D<NUM> of the wollastonite may be about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>.

In accordance with the present invention, the wollastonite may have a D<NUM> particle size in the range of <NUM> to <NUM>, for example the D<NUM> of the wollastonite may be about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>.

Unless otherwise stated, particle size properties for talc referred to herein for the inorganic particulate materials are as measured in a well-known manner by sedimentation of the particulate material in a fully dispersed condition in an aqueous medium using a Sedigraph <NUM> machine as supplied by Micromeritics Instruments Corporation, Norcross, Georgia, USA (www. micromeritics. com), referred to herein as a "Micromeritics Sedigraph <NUM> unit", and measured in accordance with ISO <NUM>-<NUM>. Such an instrument provides measurements and a plot of the cumulative percentage by weight of particles having a size, referred to in the art as the 'equivalent spherical diameter' e. d), less than given e. The mean particle size D<NUM> is the value determined in this way of the particle e. d at which there are <NUM>% by weight of the particles which have an equivalent spherical diameter less than that D<NUM> value. The D<NUM> value is the value at which <NUM> % by weight of the particles have an esd less than that D<NUM> value.

The compressed particulate compositions according to the present invention may have a tapped density of <NUM>/cm<NUM> or higher, or of <NUM>/cm<NUM> or lower. For example, the tapped density may be from <NUM>/cm<NUM> to <NUM>/cm<NUM>, or from <NUM>/cm<NUM> to <NUM>/cm<NUM>, from <NUM>/cm<NUM> to <NUM>/cm<NUM>, from <NUM>/cm<NUM> to <NUM>/cm<NUM>, from <NUM>/cm<NUM> to <NUM>/cm<NUM>, such as for example about <NUM>/cm<NUM>, or about <NUM>/cm<NUM>, or about <NUM>/cm<NUM>, or about <NUM>/cm<NUM>, or about <NUM>/cm<NUM>, or about <NUM>/cm<NUM>, or about <NUM>/cm<NUM>, or about <NUM>/cm<NUM>, or about <NUM>/cm<NUM>. As used herein the tapped density of the compressed particulate compositions are measured in accordance with ISO <NUM>/<NUM>.

The present invention also concerns methods for the production of the compositions according to the invention, i.e. methods for obtaining the compressed granulated compositions from their respective raw materials.

According to the present invention, the compositions may be obtained by (i) admixing an organic binder, optionally water and an inorganic particulate materials selected from talc and/or wollastonite, and (ii) compressing the said compounded mixture.

According to the present invention, the compression step may serve to shape the inorganic particulate matter with the organic binder and optionally the water into shapes that are practical for handling, such as tablets, pellets, granulates, aggregates, bricks, briquettes, pressings, moulds, preforms, spray-dried powders, rods, or any mixtures thereof. These compression methods are known to the skilled person in the art. For example, pellets may be obtained using a KAHL press, or a California Pellet Mill, or an Alexanderwerk press.

The addition of water may aid the cohesion of the inorganic particulate material, but it is not absolutely required. For example, no water may be added to the mixture, or some water may be added to the mixture. In case water is added to the mixture, this may be removed by heating either prior to or after the compression step.

The present invention also concerns the use of the compressed compositions as fillers in polymeric materials. For example, the particulate talc and/or wollastonite comprised in the compressed compositions according to the invention may be employed as fillers in polymeric materials, such as polypropylenes, polyethylenes, polyamides, polyester-based blends etc..

The compressed compositions may be introduced into the polymeric materials by compounding.

It should be noted that the present invention may comprise any combination of the features and/or limitations referred to herein, except for combinations of such features which are mutually exclusive. The foregoing description is directed to particular embodiments of the present invention for the purpose of illustrating it. It will be apparent, however, to one skilled in the art, that many modifications and variations to the embodiments described herein are possible. All such modifications and variations are intended to be within the scope of the present invention, as defined in the appended claims.

Micronised talc (Steamic T1 - Imerys; bulk density: <NUM>/cm<NUM>; D<NUM>: <NUM>; D<NUM>: <NUM>) was tested with and without organic binder (glycerol monostearate GMS, zinc stearate ZS, paraffin, polyethylene glycol PEG, magnesium stearate MgS, stearic acid SN d, styrene-ethylene/butylene-styrene, aqueous dispersion SEBS, and ethylene-vinyl acetate EVA). The micronized talc (<NUM> wt. -% or more) and the organic binder (up to <NUM> wt. -%) were compressed into pellets in the presence of <NUM> wt. -% water, dried and subjected to the Turbula test, intended to simulate transport of the pellets. The samples used were as shown in Table I:.

The tapped densities (d) of the various samples were measured before Turbula test (<NUM>), after Turbula test (T), and after severe Turbula test (Ts), in which ceramic beads were introduced into the sample. The Turbula test was carried out using a Turbula® T2F mixing equipment (Willy Bachoffen). It is used to shake the inorganic particulate material so as to reduce its compaction level. The method employed consisted of introducing <NUM> of the compacted powder to be tested in a <NUM> plastic container. After the container is closed, it is introduced in the Turbula basket and clamped. Then Turbula is set at full power for <NUM> minutes before the container is opened to take back the powder sample. The tapped densities were measured in accordance with ISO <NUM>/<NUM>. The results are shown in Table II:.

While the use of organic binder does not appear to show improvements on the neat (fresh) material, after simulation of transport under normal and severe conditions, the tapped densities of the products treated with glycerol monostearate and zinc stearate show clearly improved tapped densities, leading to easier handling of the compacted inorganic materials at the point of use.

The sieve residue (SR) at various mesh sizes of the pellets before (<NUM>) and after (T) Turbula testing were also measured. The results are shown in Table III:.

It is apparent that the compacted particles obtained using organic binders are all more stable under transport testing conditions.

Some of the compacted talcs shown in Table I above were tested by dispersion into a <NUM> polypropylene film.

<NUM> of High-viscosity polypropylene resin, type ATO PPC <NUM> grade <NUM>,<NUM> was introduced in the mixer (Brabender Plastograph EC plus, equipped with Mixer <NUM> which includes <NUM> cylindrical rotors), and set at <NUM> at <NUM> rpm. When the polymer had melted and torque reached <NUM> N/m, mixer speed was increased to <NUM> rpm. <NUM> of the compacted mineral was introduced, and time count started. After <NUM> mixing, or after <NUM> mixing, a <NUM> sample of the compound is taken out and cooled down.

The obtained samples were pressed into films using a Gibitre Press at <NUM>, with a <NUM> thick and <NUM> diameter mould between the press plates. <NUM> of compound was placed on the lower metal plate sandwiched between two aluminium foils. The upper press plate was placed in contact with the compound to heat it for <NUM>, then the plates were pressed at <NUM> bar on the compound for <NUM>. The press was opened to take out the <NUM> diameter and <NUM> thick film which was then cooled for <NUM> minutes before removing the aluminium foils.

The number of agglomerates greater than <NUM> were counted by optical inspection after dispersion durations of <NUM> minutes and <NUM> minutes. This was done using a Nikon binocular SMZ-<NUM>, with magnification in position <NUM> (field <NUM>). The mineral agglomerates were identified by alternating the film illumination by reflection and transmission. The black particles in transmission revealed as white in reflection were considered to be mineral agglomerates. Observation was carried out over the whole of the <NUM> diameter film. All agglomerates above <NUM> were counted. The results are shown in Table IV.

The use of most organic binders gave better results than the use of talc without organic binder.

The compacted talcs according to the present invention were loaded into polypropylene compositions at <NUM> wt. -% loading. An extruder was side fed by adding the mineral or mineral composition via forced side feeder. In addition to the compacted talcs according to the Comparative Example <NUM> above and the Examples above, an unfilled polypropylene and a polypropylene filled with a non compacted talc were tested. The polypropylenes obtained were tested for flexural modulus (ISO <NUM>), impact resistance (ISO <NUM>-1eA) and heat deflection temperature (ISO <NUM>/A). In addition the number of agglomerates greater than <NUM> was counted by optical inspection. The validity and reproducibility of the results is shown by the standard deviations (σ) obtained. The results are shown in Table V:.

The compacted talc from the Comparative Example is not well dispersed (> <NUM> agglomerates) and provides lower reinforcement and lower impact resistance. The use of the additives at <NUM> to <NUM> wt. -% ensures much better redispersion and good reinforcement, even very close to the pure talc powder.

Various talc and talc/wollastonite compositions were compacted and pelletised, and subsequently loaded into polypropylene compositions at about <NUM> wt. -% loading. Micronised talc (Luzenac A3 - Imerys Austria; D<NUM>: <NUM>; D<NUM>: <NUM>) and wollastonite (Nyglos 4W - NYCO; diameter: <NUM>; average length: <NUM>) were tested as in test series <NUM>. The organic binder employed was glycerol monostearate (GMS; Atmer <NUM> - Croda Polymer Additives).

The talc/wollastonite mixtures were treated with a GMS/water mixture, obtained by dissolving the GMS in water at about <NUM>. <NUM> talc/wollastonite mixture was mixed in a Henschel mixer at <NUM> rpm for <NUM> minutes. The relevant amount of GMS/water mixture was added carefully. After addition of <NUM>% of the GMS/water mixture, the mixing speed was reduced to <NUM> rpm at the remaining <NUM>% GMS/water mixture was added. The mixing was stopped, any material adhering to the sides of the contained was scraped down using a spatula, and the mixture was then mixed at <NUM> rpm for a total of <NUM> minutes, with a stop after <NUM> minutes to scrape down any material adhering to the sides of the contained.

The treated talc/wollastonite mixtures were compacted using a Kahl press (<NUM> compaction ratio, die <NUM>/<NUM>), with rollers at low speed. The obtained pellets were dried at <NUM> for <NUM>. The formulations as shown in Table VI were pelletised:.

Eventhough the exact amount of water in the pelletised compositions has not been measured, it is thought that this is considerably below the amount of water introduced, since a drying process of <NUM> at <NUM> was carried out, thus bringing the water content down to <NUM> wt. -% or less.

The polypropylenes obtained were tested for flexural modulus (ISO <NUM>), impact resistance (ISO <NUM>-1eA) and heat deflection temperature (ISO <NUM>/A). In addition the number of agglomerates greater than <NUM> was counted by optical inspection. The validity and reproducibility of the results is shown by the standard deviations (σ) obtained. The results are shown in Table VII:.

Claim 1:
Composition comprising
from <NUM> to <NUM> wt.-% organic binder;
from <NUM> to <NUM> wt.-% water; and
for <NUM> to <NUM> wt.-% inorganic particulate material selected from talc, wollastonite or a mixture thereof,
wherein the composition is a compressed granulated composition., such as brick, a briquette, a pellet, a pressing, a mould, a preform, a spray-dried powder, a tablet, an aggregate, a rod, a granulate, or an agglomerate, or any mixture thereof,
wherein the wt.-% is expressed compared to the total content non-aqueous components in the said composition,
further wherein the said organic binder is selected from stearic acid or its salts, paraffin, glycerol monostearate, polyethylene glycol, ethylene-vinyl acetate (EVA) and mixtures thereof.