GB1597369A - Composite material - Google Patents

Description

(54) COMPOSITE MATERIAL (71) We, KJELD HOLBEK APS, a Danish Company of Lejrevej 74, DK-4320 Lejre, Denmark, do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a process for preparing a composite material containing cellulose fibers, the composite material prepared and products prepared from said composite material.

The present invention is based upon the concept of the uniform distribution of a polymer material constituted by solid discrete particles or solid discrete fibers having polymer at least at their surfaces and optionally inorganic particles or fibers in a cellulose fiber structure by a wet process using water-soluble synthetic polymeric polyelectrolytes to obtain effective flocculation of cellulose fibers, polymer particles or fibers and optionally inorganic particles or fibers to yield, after de-watering and drying, a product in which the said additives are uniformly distributed in the cellulose fiber structure, and in which the cellulose fibers are substantially undenatured and are bonded together in the normal way. as in paper or cardboard. The polymer or polymers of the polymer material are such that the polymer material is non-sticky at room temperature and will substantially remain discrete particles or fibers upon incorporation in the cellulose fiber structure and drying. On the other hand, the polymers are such as are able to flow and bind or form films on application of energy in a suitable form, for example by heating.

The present invention accordingly provides a process for preparing a composite material having a cellulose fiber structure in which the cellulose fibers are bonded together by hydrogen bonds, comprising preparing an aqueous suspension containing, in a nonflocculated state, a polymer material in the form of solid, discrete particles or fibres, having polymer at least at their surfaces, the polymer comprising one or more synthetic water-insoluble and water-nonswellable solid polymers which are non-sticky at room temperature and film-forming at temperatures above 80"C, and a cellulose fiber pulp; co-flocculating the polymer material and cellulose fibers by addition of a water-soluble synthetic polymeric polyelectrolyte flocculating agent, and immediately thereafter dewatering the resulting suspension to form a coherent material; and drying the coherent material under conditions which do not elicit the fusion of the polymer, the polymer of the polymer material being such that the polymer material remains in the form of substantially discrete particles or fibers upon drying.

If desired, the process may involve a further step of subjecting the dried material to heat and optionally to pressure to fuse the polymer.

The cellulose fiber structure with the polymer material incorporated therein as discrete elements and optionally with inorganic material incorporated therein produced in accordance with the present invention constitutes a valuable semi-finished product which, depending upon its specific constituents and their ratio, may be utilised for a variety of important purposes which make use of the capability of the uniformly incorporated polymer to flow and bind or form a film on application of energy in a suitable form, for example by heating.

Preferably the composite material comprises at least 2% by weight of polymer material.

The form in which the polymer is incorporated is suitably one in which it is chemically substantially inert to water and to cellulose fibers (in contrast to so-called "dispersions" or "emulsions" often used as polymer forms for incorporation in cellulose pulp) whereby the inherent bonding capabilities of the cellulose fibers are substantially undisturbed, and it is possible to obtain coherent structures of the composite material with even small contents of cellulose fibers. A wide variety of polymer forms already on the market for other purposes, are available for very uniform incorporation into the cellulose fiber structure in accordance with the present invention.

The polyelectrolytes contribute to the uniform distribution of polymer material and optional inorganic material in the cellulose fiber structure, and also contribute to a high retention when the process is performed on a paper making machine, thus contributing to maximum environment acceptability.

Where the fusion (i.e. film-formation) of the polymer has not been elicited, the composite materials produced by the process of the invention may be in the form of paperor cardboard-like sheet, web, plate, rod, profile, string or granulate materials, which through later application of heat or equivalent forms of energy e.g. pressure under conditions to elicit the bond- or film-forming properties of the polymer may be converted into materials of many different types, dependent upon the ratio between cellulose fibers and polymer material, the type and character of the polymer material, the content of optional additional materials (especially inorganic materials), and the performance and severity of the heat treatment and any pressure treatment. The end products obtained by the final heat treatment may therefore vary from polymer-impregnated paper-, pasteboardor cardboard-like materials to soft, elastic, or hard cellulose fiber-reinforced polymer articles and even to panels or shaped articles immediately appearing as having inorganic character, which to a large extent is determined by added inorganic materials such as minerals, including mineral or metal particles or fibers. Common to all the end products in question, irrespective of the possible great difference in their character, is that they contain cellulose fibers and a polymer as defined above, in which the fusion (film-formation) of the polymer has been elicited, and that, hence, they have been prepared from a semianished product or "plastic" which contained cellulose fibers, the polymer material as defined above distributed evenly between the cellulose fibers, and polyelectrolyte, and which semi-finished product was, for most practical purposes, a continuous (that is bonded together through the cellulose fibers) sheet-, web-, panel-, rod-, profile- or string-shaped material. In some aspects of the present invention, the cellulose fibers constitute a relatively large proportion of the end product and/or to a large extent contribute to the character of the end product, whereas other end products prepared from the semi-product essentially show properties determined by the polymer material used and the additives used; in such cases, the cellulose fiber structure has primarily served as a carrier material in the semi-finished product and as an aid in obtaining an even distribution of polymer material and added inorganic material and to obtain further advantages which appear from the following.

In a preferred embodiment of the process of the invention, inorganic material in the form of mineral or metal particles or fibers is added to the aqueous suspension prior to co-flocculation, and is evenly distributed throughout the cellulose fiber structure.

The above-mentioned semi-finished product obtained upon drying under conditions which do not elicit the fusion of the polymer may, if desired, be subjected to treatment eliciting the fusion of the polymer immediately subsequent to the drying, optionally in the same production line, for example through heat and optionally pressure treatment, or alternatively, it may be shipped as it is or after granulation, in other words as a "plastic" or semi-finished product for later preparation of end products from this semi-finished product through desired shaping or moulding and eliciting fusion of the polymer.

In the present context, the term "film-forming at temperatures above 80"C" is intended to characterize a polymer which, when applied, in the form of a dry powder, on to a surface and heated to above 80"C is capable of flowing to form a film within at most 60 minutes.

Preferably, the film-formation under the conditions mentioned will take place in the course of about 10 seconds or less to about 15 minutes, and it is often preferred to use polymers, the film-formation of which within such shorter periods is only elicited at temperatures above 1200C. Because of the water-insoluble and water-non-swellable character of the polymers used in the process of this invention, they are able to form a film which is substantially water-proof and water-resistant.

Polymers complying with the above requirements are various thermoplastic polymers, which during the heat treatment may further polymerize, but will not necessarily further polymerize, and various thermosetting polymers, including such thermosetting polymers which polymerize by a built-in curing or cross-linking agent, the effect of which is released at a certain heat treatment, and the effect of which may have a more or less quick on-set.

Polymers which are in the form of "dispersions", "emulsions" or "sols" in which the particles coalesce with each other to form films upon evaporation of water are not contemplated as polymer materials for the purpose of this invention. As indicated above, such "dispersions", solos" or "emulsions" of more or less sticky resin materials are widely used as additives for cellulose pulps prior to sheet formation, for example to impart a better wet strength to the paper material. Common to these resin materials is that they have at least a certain affinity to water and the wet cellulose fibers, but they also show a tendency to migrate with the water. Furthermore, the process, additives and modificatons used to emulsify or disperse such polymers in water and/or to impart to them their emulsifiable or dispersible properties, at the same time tend to reduce their final strength properties, and they will generally not be capable of yielding as strong films or bonds as the water-insoluble and water-non-swellable solid polymers used according to the invention which will not coalesce under the incorporation and drying conditions and which can be characterized as chemically substantially inert to water and cellulose fibers and, hence, will not disturb the pH conditions of the cellulose pulp or the hydrogen bonds between the cellulose fibers.

Thus, the polymers used according to the present invention are mostly those which have not been designed or adapted for incorporation in cellulose pulps, and yet, it has been found that by addition of the polyelectrolytes, the polymers may be effectively distributed evenly and retained in the cellulose structure without migration during web formation.

Only when the film-forming property (i.e. fusion) of the polymer is elicited, will the polymer of these substantially inert elements flow and form bonds or even a coherent film m the material.

Examples of polymers suitable for the purpose of the present invention include polyolefins such as polyethylene and polypropylene, vinyl polymers such as polyvinyl chloride and polyvinyl acetate, polystyrene, polyimides, polyamides, polyacrylates, ABS polymers, epoxy resin, epoxy/phenol resins, phenol resins, urea resins, melamine resins, polyester resins, melamine-polyester resins, cross-linked acrylic resins, silicone resins, polyurethane resins, and copolymers thereof such as copolyamides. Such polymers are available in solid forms in which they may be converted into a coherent film at temperatures above 80"C for periods from about 10 seconds to about 15 minutes. The heating treatment may, for example, be performed by high frequency treatment, ultrasound treatment, infrared radiation, microwaves and/or conventional application of heat.

One interesting polymer material for the purpose of the present invention is finely divided polymer material prepared from waste, for example suitable thermoplastics such as polyethylene ground at low temperature.

Also synthetic vulcanisable elastomers such as SBR in suitable forms are useful as the polymer for the purpose of the present invention.

For the preparation of composite materials which, in their form as finished products or shaped articles are to be used for outdoor purposes, it is advantageous to use inherently weather-resistant polymers, for example single component addition polymers such as cross-linked acrylic resins, polyesters, epoxy polyesters and polyurethanes, but also for example polyvinyl chloride, polypropylene and polyethylene are suitable polymers for preparing products for outdoor applications. For other purposes, for example containers for liquid products, including beverages such as milk or juice, polyethylene, polypropylene and copolymerized or otherwise hydrophobized melamine resins, for example melaminepolyester resins, are preferred polymers.

It is within the scope of the present invention to use more than one polymer material.

Thus, for example, a cross-linked synthetic polymer such as a polyester can be combined with a thermoplastic polymer such as polyethylene, polyvinyl chloride, or polypropylene. It is also possible to incorporate for example powdered bitumen or bitumen emulsion which acts as a cheap structure-filling, water-resistant component, preferably together with incorporation of a water film-disrupting surface-active material such as a tenside.

Another example of a combination of two polymer materials is a combination of non-plasticized polyvinyl chloride and plasticized polyvinyl chloride. According to the invention, it has been found that the combination of an essentially non-plasticized polymer and a relatively highly plasticized polymer is often to be preferred over the use of one polymer plasticized to a lesser degree.

When the polymer material used according to the invention is in the form of particles consisting of polymer throughout, such powdery polymer material usually has a particle size of the order of 1 - 500 y, preferably 1 - 200 11 and especially 10 - 80 p. Alternatively, the polymer material may consist of polymer applied on an inorganic carrier, for example metal particles such as particles of brass, iron, zinc, aluminum, copper or bronze, or mineral or other inorganic particles such as TiO2, iron oxide, wollastonite, kaolin, de-glassed glass (i.e. partly crystallised glass formed by cold hardening the glass in a molten condition), calcium carbonate, quartz, sand, silica, steatite, talc, aluminum silicate, Synopal, barytes, diatomaceous earth, or amorphous SiO2. Such particles of polymer applied on an inorganic carrier typically have a particle size of 1 - 500 ij, preferably 1 - 200 'L. Alternatively, the polymer material may be in the form of polymer fibers or polymer applied on an inorganic carrier in the form of mineral fibers such as glass wool, glass rovings, stone wool, slag wool, kaolin wool or calcium silicate wool, or metal fibers such as fibers of brass, copper, aluminum, bronze or iron. The length of such inorganic fibers with polymer applied thereon is typically from 100 11 to 3 mm, and the thickness is typically from 5 to 30 ii. Certain minerals are available in particles which are rather elongated, for example wollastonite, but in the present context are considered particles and not fibers.

Some polymer materials with polymer applied on an inorganic carrier are commercial products manufactured, for example, for use in powder coating processes. The fraction of such products in the range below 30 U and above 80 U are usually considered as waste, but for the purpose of the present invention, such fractions, like the fraction in the range of 30 80 Il, are well suited. Examples of such commercial powder coating materials are polyolefins or epoxy, polyester, acrylic or polyamide resins applied on TiO2 particles, the amount of the polymer being 40 - 90% by weight, calculated on the total weight of the material, the higher weight amounts usually applying when the polymer is a polyolefin, a weight amount of 40 - 60% by weight being the normal range when the polymer is an epoxy, polyester, acrylic or polyamide resin.

For the purpose of the present invention, a considerably smaller amount of polymer applied on the inorganic carrier will be sufficient for most purposes, for example 2 - 40% by weight, 2 - 20% by weight being typical values for fibrous carrier materials and 5 - 40% by weight being typical values for particulate materials.

Particulate or fibrous polymer materials in which the polymer is applied on an inorganic carrier may be prepared in various ways. One way for preparing particulate polymer materials on an inorganic carrier is to extrude a mixture of carrier and the polymer and thereafter grind the mixture. When a thermosetting polymer is used in this operation, the extrusion should take place at a temperature at which the curing of the polymer is not elicited. The best compatibility between the polymer and the inorganic carrier material is obtained when one of these materials has a positive electrical surface potential and the other one has a negative electrical surface potential. Most polymers useful for the purpose of the present invention have inherently a negative surface potential, and most carrier materials also have negative surface potential, and when combining such materials which both inherently have a negative surface potential, it may be suitable to treat the carrier material with an agent changing the surface potential of the inorganic material from negative to positive. Various so-called coupling agents, i.e. compounds which are able to combine with both polymer and inorganic materials and thereby increase the compatibility between the polymer and the inorganic carrier or additive material have been found to have this property.

Such coupling agents are for example silanes (for example Silan A 1100, which is y-aminopropyltriethoxysilane from Union Carbide Corporation, New York, N.Y., U.S.A., and Dynasylan MEMO (y-methacryloxypropyl trimethoxysilane) or Dynasylan GLYMO (y-glycidyloxypropyltrimethoxysilane) from Dynamit Nobel, Germany, and chromium complexes (for example Volan (Volane is a Registered Trade Mark) (a methacrylic chromium complex of Werner-type from Seppic, Paris, France)).

To ensure a particularly effective distribution of the polymer on the carrier particles or fibres and to obtain a coherent polymer coating of maximum uniformity on the particles or fibres, a preferred process for preparing polymer-coated particles or fibers comprises maintaining particles or fibers of carrier material under vigorous agitation while in dried and optionally heated condition, for example with stirring or in an air flow, while the polymer is sprayed or added little by little in liquid or semi-liquid condition. (The polymer may also be added in solid state when the carrier material has a sufficiently high temperature during the application process, as the polymer, for example in the form of solid particles, will then be converted by the heat into the liquid or semi-liquid state necessary for the coating.) For example, a powder of wollastonite particles may be heated to about 350"C for removal of water film on the surface, whereafter at a temperature of above 1000C (to ensure that no water film is re-established on the particles during the process) a polymer in solid, liquid or semi-liquid state may be added to the agitated powder, for example a polyester or a paste-formed solven-free single-component epoxy resin such as "Araldit AV8" ["Araldite" is a Registered Trade Mark.] (from Ciba-Geigy, Switzerland) which is a thermosetting epoxy resin paste, or polyethylene.

The agitation of the inorganic carrier particles or fibers may be achieved in various ways, for example, it is possible to coat the fibers in a fluid bed with polymer, optionally with utilization of opposite electrostatic charge on fibers and polymer, and to apply the polymer (and optional processing aids, including tensides) immediately subsequent to the formation of glass wool fibers or stone wool fibers, and while these are being transported, by means of vacuum or an air flow, respectively, from the spinning elements where they were formed.

Mineral fibers with a coating of polymer which is film-forming at temperatures above 80"C, especially a coating constituting 2 - 40% by weight of the combined material, constitute an especially interesting polymer material which may be prepared as described above, and which, in addition to being used in the process of the invention, may be used for many other purposes where a film-forming polymer is to be used. As such materials show a large exposed surface of film-forming polymer in comparison with the amount of polymer, they may be used as very economical substitutes for polymer materials consisting solely of the polymer in question, for example in the preparation of various composite materials of otherwise known type. Apart from this, they may be used for the preparation of various novel products, the special properties of which depend upon the bonding between such mineral fibers with a coating of film-forming polymer.

Also fibers consisting solely of the film-forming polymer or a combination of film-forming polymer may be used. However, an advantage of polymer materials comprising polymer applied upon particles or fibers, in addition to the fact that these may inherently, by their incorporation, incorporate a desired inorganic component of the composite material, is that polymer having an inherent density below 1 will result in polymer materials with a density above 1 when combined with the inorganic carrier in sufficient amount. Particles or fibers having a density above 1 are more efficiently co-flocculated with cellulose fibers.

In one special aspect of the invention, the polymer of the polymer material may contain a blowing agent which, under the temperature conditions at which the fusion of the polymer occurs, simultaneously foams up the polymer to yield a cell structure, for example by vigorous evaporation or chemical reaction with evolution of a gas. Hereby, cellulose fiber-reinforced composite materials can be obtained. Polymers, for example polystyrene, containing blowing agents are commercially available. The blowing system of the polymer selected should be one which is only elicited at a suitable high temperature so that there will not be any undesired foaming during the drying of the composite material.

When an inorganic material in the form of mineral or metal particles or fibers is to be incorporated in the composite material, such particles or fibers are preferably the same particles or fibers as are mentioned above as possible carriers in polymer materials, that is, metal particles such as particles of brass, iron, zinc, aluminum, copper, or bronze, or mineral or other inorganic particles such as TiO2, iron oxide, wollastonite, kaolin, de-glassed glass (as hereinbefore defined), calcium carbonate, quartz, sand, silica, steatite, talc, aluminum silicate, Synopal (Registered Trade Mark), barytes, diatomaceous earth, or amorphous SiO2, the particle size of such inorganic particles typically being 1 - 500 ,u, or mineral fibers such as glass wool, glass rovings, stone wool, slag wool, kaolin wool or calcium silicate wool, or metal fibers such as fibers of brass, copper, aluminum, bronze, or iron. A special type of inorganic material which may be incorporated is an inorganic binder (conventionally termed a hydraulic binder) such as cement or kaolin cement. In that case, after drying the composite material, it is subjected to a heat treatment to fuse the polymer, optionally water is added to the material and the inorganic binder is allowed to harden. To improve the compatibility between polymer and added inorganic material when the film-forming properties of the polymer are later on elicited, a "coupling agent" of the type mentioned above, for example a silane, may be used. The inorganic material may previously be treated with the coupling agent, or the coupling agent may be added to the cellulose pulp, for example simultaneously with the inorganic material.

In the process of the invention, the polymer material is incorporated in an aqueous suspension of cellulose fibers, also called a cellulose fiber pulp, optionally together with inorganic material as discussed above. The cellulose fiber pulp may be prepared in the usual manner from for example sulphate or long-fibered sulphite cellulose, waste paper and waste cardboard, straw cellulose, thermomechanical cellulose fibers and optionally synthetic cellulose fibers such as rayon fibers. Waste cardboard is an especially suitable starting material. Cardboard may be converted into a cellulose fiber pulp by treatment in a pulper, optionally at an elevated temperature of up to 600C. The cellulose fiber concentration in the resulting cellulose pulp may, for example, be 1/2 - 4% by weight, usually at the most about 2% by weight and in ordinary paper making machines often 1/2 - 1% by weight. The cellulose fiber pulp may be treated according to conventional paper technology methods, for example by treatment in a hydrocyclone and in deflakers.

At a suitable point during or after pulping and prior to web formation, tensides, for example non-ionic tensides, antifoaming agents, aluminum hydroxide, ammonium phos phate, -diphosphate or -polyphosphate may be added. The non-ionic tensides reduce the interface activity, break molecular water film on particles and fibers and contribute to removal of minor air bubbles from polymer material and the optional inorganic material and may also contribute to the obtainment of a more compact final product. Aluminum hydroxide imparts greater fire resistance to the resulting material, and the ammonium phosphate materials mentioned are known defibrating agents used in paper industry and contribute to make the material more fire resistant. Also other fire inhibiting agents for example antimony trioxide or halogen-containing compounds, may be added at this stage.

The suspension to be flocculated should desirably conform with such conditions with respect to pH value and zeta potential which are known within paper technology to yield a good retention. The pH is usually in the range of 5 - 8 but may also be higher, for example up to 9. The zeta potential is preferably kept at a low numerical value which is between +20 and -20 millivolts, preferably in the range of about +10 to -10 millivolts and especially in the range between +5 and -5 millivolts. It is well known that changes of the pH and/or ionic strength of the suspension will change the zeta potential. Also, for example addition of strongly cationic or strongly anionic tensides will substantially change the zeta potential and may in certain cases even convert the zeta potential from positive to negative or vice versa. Silanes and polyelectrolytes have also been found to have a considerable influence upon the zeta potential of suspensions of the present kind.

In order to further improve the flocculation, opposite electric surface potential of cellulose fibers and polymer material may be utilized. Cellulose fibers inherently have a relatively high negative surface potential, and the same applies to certain polymer materials such as polyesters and epoxy resins. It may be suitable in such cases to "convert" the surface potential of the polymer-material, the example using a cationic tenside of a type which, when it has been applied on the polymer with subsequent drying, cannot be re-dissolved in water, for example Fintex 577 which is described in Experiment A which follows. Also treatment with silanes and subsequent drying to build up a monomolecular layer may convert an inherently negative surface potential on polymers into positive. The treatment of polymer materials with cationic tensides can be performed for example by adding the cationic tenside to an aqueous suspension of the polymer material and thereafter drying the polymer material. Another possibility is to treat dried, heated polymer particles with cationic tenside. A third possibility is to incorporate cationic tenside in the polymer proper.

The Schopper Riegler degree of the cellulose fibers in the cellulose pulp may vary within wide limits, for example from about 15 to about 80. Often, the Schopper Riegler degree will be in the range of 30 - 60, for example 30 - 40 or especially 40 - 60. When the cellulose fibers are thermomechanical fibers, the Schopper Riegler degree is preferably lower, for example about 15.

According to the invention, the polymer material is incorporated by co-flocculation by means of a polyelectrolyte. Polyelectrolytes are macromolecules with "built-in" ionic groups, vide for example, Römpps Chemie-Lexikon, 7th Edition, Stuttgart, 1975, page 2755 - 2756. The polyelectrolytes preferred for the purpose of this invention are synthetic water soluble polyelectrolytes suitable for flocculation purposes, but are not necessarily polyelectrolytes which have previously been suggested for use in cellulos preferably 0.2 - 1% by weight, calculated on the dry weight of the components of the suspension. In addition to assisting in improved flocculation in systems where an inorganic material is added, the silane will also later on, upon eliciting of the film-forming properties of the polymer, be advantageous in that it functions as a coupling agent.

When silane and conventional cellulose fiber flocculating agents such as alum are added, these are usually added before or during the mixing of the components of the suspension.

The optimum flocculation in a particular system may be assessed by the skilled art worker by means of easily performed introductory model experiments.

The polymer material may be combined with the cellulose pulp in the machine chest where effective mixing of these components and the optional inorganic material may be performed with suitable mixing means such as a stirrer, the polyelectrolyte being thereafter added immediately prior to passing the suspension to the dehydrating stage.

It is often preferred to add the polymer material to cellulose pulp as an aqueous suspension rather than as a dry material. Such suspension may suitably be prepared in a high concentration, for example a solid content of 30 - 90% by weight, by vigorous agitation, using, for example, surface active agents such as Berol 373 ["Berol" is a Registered Trade Mark], the data of which are stated in connection with the Examples.

Also, thixotropy agents may be added to the suspension to avoid sedimentation. The suspension of the polymer material is suitably maintained at room temperature. When an inorganic material is to be added, this may be either added separately, in dry form or in aqueous suspension, or it may be included in the suspension containing the polymer material.

When the polymer material and/or the inorganic material comprises fibers, it is desired that they are in defibrilated form before they are combined wth the cellulose pulp. Effective defibrilation may be obtained by beating the fibers in the presence of a suitable tenside, and it has also been found according to the invention that agitation, for short periods of at the most 1 minute, of the fibers with a polyelectrolyte results in an efficient defibrilation of fibers. Fiber materials are preferably defibrilated in aqueous suspension of a concentration of less than 1% by weight, for example, an effective method of defibrilating glass wool is to beat glass wool in a concentration of 0.5% in water, for a period of at the most 1 minute in the presence of a cationic polyelectrolyte such as Prodefloc C1 in a concentration of for example 0.01%.

When the composite material is to be used for articles which, in their end use, are to be stable for long periods under conditions involving exposure to moisture, the cellulose fibers may be protected against deterioration by addition of an antimicrobial agent, for example a fungicide. The antimicrobial agent may be applied on the surface of the finished articles subsequent to their final heat treatment, for example in the form of antimicrobial sprays or as constituents of a paint coating or other coating.

In the preparation of composite materials for articles which are to be exposed to moisture, for example, roofing panels or building panels, it may also be suitable to add an anti-moisture impregnating agent, for example one of the known "wood protecting oils" such as Pinotex Goriol, or Bondex, preferably in colourless form. These wood protecting oils may easily be emulsified and co-flocculated with the cellulose pulp. Bitumen emulsion and paraffin emulsion are other suitable impregnating agents which may be added to the cellulose pulp prior to the flocculation. An interesting impregnating agent is an oil emulsion with an added cationic tenside which is decomposed at temperatures of about 100"C. By addition of such emulsion, the following function can be obtained: First, the emulsion is co-flocculated with the cellulose pulp, and in the web formation, the cellulose fibers are bonded through hydrogen bonds. In the drying operation, the tenside from the oil emulsion is decomposed due to the drying heat, and through this, the cellulose fibers are effectively impregnated with the oil which has a tendency to penetrate into the ends of the cellulose fibers. On the subsequent eliciting of the film-forming properties of the polymer, a strong, water-resistant material is obtained.

With respect to the water resistance of the articles prepared from the composite material, it may be suitable to use tensides and polyelectrolytes which are decomposed during the heat treatment, as tensides and polyelectrolytes tend to be hygroscopic.

In connection with the preparation of composite materials comprising cement, it has been found that the optimum flocculation and retention is obtained by first adding a cationic polyelectrolyte and subsequently adding a further polyelectrolyte, vide Examples 50 - 54.

In the following description of the process, the paper making machine is described as a machine of the endless wire type, but the process may also be performed on any other type of paper making machine, or other machine adapted for de-watering a flocculated suspension to form a web or sheet, for example the hydroformer or rotoformer type ("non-woven' '-type).

A successful co-flocculation manifests itself in that the added particles or fibers of polymer material and optionally other additions, especially inorganic material, are retained practically completely in the flocs on the wire and are not entrained with the water passing through the wire, not even when very small particles of for example 5 U or less are concerned. The de-watering treatment is performed in a manner known per se and with a wire velocity adapted to the character of the cellulose pulp, the content of added materials, the efficiency of suction and the desired web thickness. In some embodiments of the present invention, it is desired to prepare relatively thick sheets or webs with sheet weights up to for example 2 - 3 kg/m2 (dry weight), and in these cases it may be suitable to keep the wire velocity small for certain types of paper making machines. Normally, the wire velocities in ordinary paper making machines are between 10 and 500 meters per minute, but when it is desired to prepare webs with high sheet weights up to for example 2-3 kg, wire velocities as low as 2 - 10 meters per minute may be used.

Thereafter, the web formed by the bonding between cellulose fibers (hydrogen bonds) may be passed from the wire to drying and rolling up stages in a manner known per se, for example through passage between the conventional wet press rollers and over heated drums, optionally with a cooling drum immediately prior to the winding up. It is important that the drying is performed under time/temperature conditions which will not elicit the film-forming properties of the polymer material. Suitable drying temperatures are in the range up to about llO"C, for example in the range of 80 - 100"C. To obtain good results in the later eliciting of the bonding or film-forming properties of the polymer, it is necessary that the web has previously been effectively dried, preferably to a water content of at the most 5% by weight or most preferably to constant weight. It might in principle be possible to ship the semi-finished product with a higher water content, for example up to 50% by weight, and the further drying could then be performed in connection with any shaping treatment prior to the final heat treatment. However, the most suitable "dry" semi-finished product will be one having a water content of at the most 25, especially at the most 15, % by weight and preferably at the most 5 % by weight.

The composite material of the invention in the form of the semi-finished product may be shipped in the form of rolls, sheets or strips, or, if the de-watering has been performed in an extruder, in the form of an extrudate, but it may also, in the manufacturing station, be punched or cut to desired shapes and sizes corresponding to the products or articles to which it is to be converted in the final heat treatment. The waste material resulting from the cutting or punching operation may be recycled; it may simply be beaten in the pulper and can constitute part of the starting material for a later production.

When it is desired to subject the semi-finished product to the final heat treatment in the factory where the semi-finished product is produced, the dried web can suitably proceed directly to the further treatment where the temperature is elevated from drying temperature to film-forming temperature. Prior to or simultaneously with the elevation of the temperature to the film-forming temperature, the web or sheet may be subjected to a forming or shaping operation, usually under pressure. This shaping operation may also be performed at a stage where the web has not been totally dried, the further drying being then performed in a later stage.

As mentioned above, the composite material in the form of the semi-finished product may also be prepared in the form of an extrudate in that the wet material is subjected to extruding in a manner known per se the drying being performed simultaneously with or subsequent to extruding. The extruding technique may be used for preparing even very thick materials in large plate or tube dimensions.

When the semi-finished product of the invention is to be in laminated, possibly cross-laminated form, this may either be prepared by laminating moist webs on or after the wire of the paper making machine, or dry sheets or webs may be moistened a little, for example with steam, and thereby brought to adhere through the hydrogen bonds of the cellulose fibers. Preferably the laminate has a higher content of polymer in its surface layers than in its interior layers.

The composite material of the invention can easily be adhered to limiting surfaces, for example metal or glass surfaces, as the polymer, on eliciting of the film-forming properties, will serve as adhesive to the limiting surfaces in question. In this way, both a cohesive and an adhesive effect are obtained in the heat treatment. This may for example be utilized in the preparation of electrically isolating components which are to be arranged between limiting surfaces of metal, for example in the preparation of commutators in which the isolating material may be introduced in the form of a material of the invention and adhered to the metal limiting surfaces in a very simple and efficient way. Another utilization is the preparation of sandwich materials in which the composite materials of the invention may be used as "binder sheet" between for example two metal or glass plates.

When an inorganic binder is incorporated as inorganic material in the composite material, it is usually not preferred to perform any pressing operation after the inorganic binder has hardened. Composite materials containing inorganic binder may, according to the invention, be treated in two different ways subsequent to web formation: Either, the composite material is dried only to a stage which leaves sufficient water in the material for hardening the inorganic binder, and the hardening of the inorganic binder is allowed to proceed, the heat treatment being performed subsequent to the hardening of the inorganic binder, but without any substantial pressure applied during the heat treatment, or the composite material is dried and heat-treated before the inorganic binder hardens, whereafter the hardening of the inorganic binder is allowed to take place, either simply by exposing the composite material to ambient humidity, or by positively applying water to the composite material subsequent to the heat treatment.

In the products of the present invention, the proportion of cellulose fibers may vary within wide limits, e.g. from 5% by weight to 95% by weight, calculated on dry weight of the material.

The products having a cellulose fiber content in the upper part of the range, for example 95% cellulose fibers and 5% polymer material, may be paper- or cardboard- like materials, the strength and water resistance properties of which are improved by the incorporated polymer material. If the polymer is one which easily fills all cavities, for example low density polyethylene, such composite materials, after the heat treatment, may be used as water-resistant or liquid-proof packaging materials, for example for containers for beverages such as milk or juice. With proper selection of polymer, for example low density polyethylene, these materials may be heat-weldable, and by incorporation of polymer materials improving the strength properties, for example polyester-coated fibers, very strong packaging materials may be obtained. Another example of an interesting material for milk containers with improved rigidity properties is a composite material of the invention in the form of a laminate with cement and polymer material in the outer layers thereof. If materials of this kind are to be coloured, a colour pigment may be incorporated as an inorganic material in the way described above, or the polymer material may consist of a polymer applied on an inorganic colour pigment as carrier, but the colouring may also be performed in conventional way after the sheet or web formation. However, any colouring of the cellulose fibers should be performed prior to the final heat treatment, as the cellulose fibers would otherwise become wholly or partially unavailable to the colouring treatment.

Any printing of the materials should also preferably be performed prior to the final heat treatment.

From webs having a high content of cellulose fibers, it is also possible to prepare products having properties resembling wood or hard wood fiber boards by subjecting one thick layer or several superimposed layers of the semi-finished product with a polymer suitable for this purpose to heat and pressure treatment. The material becomes more compact and rigid, the higher pressure is applied. Strength properties of a laminate of this type may be further improved by arranging the layers with alternating fiber direction, that is, alternating manufacturing direction, like plywood, and layers of other materials may also be included, for example aluminum foil, lead foil, or composite materials of different content, also suitably prepared according to the invention. The bonding between the layers of such laminate may be obtained solely by the heat and pressure treatment, the polymer bonding together the layers. Lamination may also be utilized for preparing other types of composite materials of the invention, and a laminate be shipped as such for later heat-treatment. A suitable composition for a wood- or wood fiber panel-like product is, for example, 85% of cellulose fibers and 15% of polypropylene particles or polyvinyl chloride particles. If desired, part of the cellulose fiber content may be replaced with wood shavings or straw particles, for example, the composition may instead be 15% of polypropylene particles, 60% of cellulose fibers and 25% of wood shavings or straw particles.

The products which, in addition to cellulose fibers and polymer, contain an inorganic material, either incorporated as such or as the carrier in the polymer material, often have cellulose fiber contents in the range of 15 - 35% by weight. Such materials are interesting semi-finished products for preparing a wide spectrum of end products. Examples of these and similar materials are: A composite material for preparing various articles which are conventionally prepared from polymer throughout or from other materials, for example system toy bricks or other shaped articles such as dishes, dispensable cutlery, rice bowls, serving trays, cartridge cases, packaging drums, and district heating tubes, may consist of 30 - 70% by weight of cellulose fibers, about 40% by weight of mineral wool fibers, and about 30% by weight of polymer material in which the film-forming polymer is applied in an amount of 15 - 40% by weight on mineral wool fibers. This composite material as a single layer, a laminate, a wound-up strip or an extrudate, may be converted to the above-mentioned shaped articles by compressing with heat, for example at a pressure of 2 kg/cm2 - 10,000 kg/cm2, and a temperature of about 100"C. (It applies quite generally that when eliciting the film-forming properties of the polymer materials, one should not employ temperatures above 1700C for any longer period when it is desired to avoid any damaging of the cellulose fibers. However, brief (for example up to 60 seconds) heating to higher temperatures such as 250"C is usually tolerated.) When the shaped articles are to be coloured, pigment particles may be incorporated instead of part of the mineral wool fibers, or the polymer proper may be coloured. Surface smoothness and material strength of the finished shaped articles depend to a large extent on the shaping conditions: the higher pressure, the smoother surface and the better strength. Typical pressures are from 10 - 100 kg/cm2 and up to pressures of 1000 10,000 kg/cm2. By suitable selection of polymer, for example heat-curing polyester resin or melamine-polyester with short curing time, a very short time cycle in the die may be obtained. For system toy bricks, a suitable polymer will, for example, be an ABS, epoxy or polyester resin, and a suitable polymer for dishes and rice bowls is a copolymer of melamine. Suitable polymers for e.g. spectacle frames, knife handles and artificial teeth are for example epoxy polyester, polyester or acrylic resin.

A strong structural material for preparing for example laminate panels, boats, drums, boards, chairs or automobile bodies may be composed of 15% by weight of cellulose fibers and 85% by weight of mineral wool fibers, covered by about 15% by weight of polyester.

The laminate panels may be prepared in the same way as described above, and they may be used for the same purpose as ordinary commercial laminate panels, for example for interior walls, kitchen table tops or bathroom wall cover, and they are advantageous in that they are most simply prepared from cheaper starting materials than the conventional laminate panels. For the preparation of for example boats, sheets or strips of the semi-finished product of the invention in moistened condition may be shaped in the desired configuration, whereafter the eliciting of the film-forming properties of the polymer is performed under pressure (for example 100 kg/cm2) and heat.

A fibrous material, for example suitable for roofing felt and floor felt, may consist of 15 20% by weight of cellulose fibers, 50 - 70% by weight of mineral wool fibers and 15 - 25% by weight of a polymer material which is, for example, glass, stone or slag wool fibers of lengths about 3 mm, or glass rovings with a coating of 15 - 20% by weight of film-forming polymer or which is inorganic particles, for example of sand or wollastonite, having a coating of 20 - 40% by weight of film-forming polymer. Alternatively, the film-forming polymer could be present as particles consisting solely of the polymer, the inorganic materials mentioned then being added per se, in which case the amount of polymer will preferably be 5 - 10% higher.

A wear-resisting flooring material of the invention may consist of 15% by weight of cellulose fibers, 50% by weight of glass fibers and, as the polymer material, for example a combination of 20% by weight of polyvinyl chloride and 50% by weight of polymer-coated mineral wool fibers.

A composite material for preparing hard, strong and electrically insulating shaped articles, for example electrical isolators, including commutator materials, hair curler bodies, and printed circuits, may, for example, contain about 15% by weight of cellulose fibers, suitably straw cellulose, and 85% of polymer material consisting of wollastonite particles of 5 - 200 It with a coating of 10 - 50% by weight of polymer, for example a polyester or an epoxy polyester resin. On heat treatment with or after high pressure, that is, pressures above 1000 kp/cm2, preferably above 4000 kp/cm2, an almost mineral or stoneware-like, compact product with high strength is obtained. Similar products may also be obtained if the wollastonite particles and the polymer are incorporated separately.

Composite materials resembling these may also b prepared from powders of the mineral and polymer components in question, but the use of the composite material of the invention avoids all problems involving incompatibility or de-mixing. Also, the sheet or plate form blank of the composite material is easy to handle, and for preparation of shaped articles of greater thickness, the composite material may be used in laminated form, including rolls, or as an extrudate. Also granulates may be used. Similar material for the same field of use may, for example, consist of 20% by weight of cellulose fibers, about 60% by weight of wollastonite powder having a particle size in the range of 5 - 200 xu (all powders used according to the invention preferably show a particle size characteristic corresponding to the grain curve of concrete) and 20% by weight of a commercial particulate powder coating material consisting of epoxy resin on 435to TiO2 and 2% BaSO4.

Hard, weather-proof and durable panel materials, for example for use as exterior p nels on buildings, such as roof panels, may be prepared from a composite material containing 15 - 40% by weight of cellulose, the remainder being inorganic material and polymer, the polymer content being 15 - 40% by weight, and the content of inorganic material being 20 70% by weight. One example is a composite material having 35% by weight of cellulose fibers and 65% by weight of polymer material consisting of mineral wool fibers having a coating of 15% by weight of polyester. Various other composite materials suitable for this purpose are illustrated in Examples 1 - 24 and 45 - 54. One preferred roofing panel material comprises about 20% by weight of cellulose fibers, for example from cardboard, 40 - 50% by weight of inorganic particulate material, for example wollastonite or sand having a particulate size below 300 Il, and 30 - 40% by weight of polymer particles. The polymer particles may, for example, comprise a relatively rigid polymer and a softer, to a greater extent structure-filling polymer. For example, the relatively rigid polymer may be non-plasticized polyvinyl chloride, and the other polymer in the combination may be plasticized polyvinyl chloride. Cross-linked polyethylene is another good polymer for use in such roofing panels. In the preparation of roofing panels, the composite material, either a single layer or a laminate of several layers (for exampl formed by web lamination of several webs, suitably by running suspension from several tanks on one and the same wire, in which case there is suitably a larger content of polymer in the bottom and top layers) is shaped in the desired configuration while still wet, for example through corrugated rollers to form corrugated roofing panels, whereafter the shaped panels may be dried, either in oven or between drying rollers, and thereafter subjected to a temperature eliciting the filmformation of the polymer, for example 1700C, if necessary or if desired under pressure, either between rollers or in a platen press.

A composite material which is suitable as backing for flooring materials, for example as backing for flooring e.g., polyvinyl chloride foam flooring, may be prepared from e.g. 15 25, preferably about 20, % by weight of cellulose fibers, 40 - 60% by weight, preferably about 50% by weight, of mineral fibers, for example glass wool or stone wool, and 30 - 40% by weight, preferably 30 - 35% by weight, of polymer. Such backings have previously been prepared of asbestos fibers, but due to the health hazards associated with asbestos fibers, it is necessary to find substitutes for asbestos-containing products. The present backing constitutes a dimension-stable, acceptable and compatible backing for polyvinyl chloride floorings. Examples of suitable polymers for the purpose are polyethylene, for example cross-linking polyethylene, and polyvinyl chloride. When the polymer is polyvinyl chloride, the backing may be "welded" to the remaining components of the polyvinyl chloride flooring concomittantly with the eliciting of the film-forming properties.

The composite material of this invention may also be used for preparing friction materials, for example brake linings. For this purpose, materials are incorporated which are known to be suitable in friction materials, for example brass powder, barium sulphate, graphite, bronze powder, and wollastonite and Synopal or slag wool fibers. Composite materials suitable for brake linings are illustrated in Examples 33 - 36. When preparing materials for brake linings, it is especially preferred that the fiber direction of the finished brake linings or brake bodies are, to the extent possible, perpendicular to their contact face.

To this end, a laminate of several layers of friction material-containing composite material is made, the fiber direction being the same in all the layers, the laminate is subjected to heat and pressure to elicit the film-forming properties of the polymer, and the resulting material is thereafter cut out into brake linings in a direction perpendicular to the fiber orientation.

In the Experiments given below, percentages are by weight unless otherwise indicated.

Experiment A In a kneader, 25% by weight of wollastonite powder (FW200 from Pargas, Finland) of particle size 1 - 200 11 were mixed with 75% by weight of a liquid polyester containing cross-linking agent and accelerator. The resulting mixture was extruded in a conventional plastic extruder which makes the polyester solidify. Thereafter, the resulting material was treated in a hammer mill until 80% of the material had a particle size of less than 70 p.

In a corresponding manner and from the same starting materials, powdery wollastonite/ polyester materials were prepared with a content of 35% of wollastonite and 65% of the polyester, 45% of the wollastonite and 55% of the polyester, 70% of wollastonite and 30% of epoxypolyester, and 70% of wollastonite and 30% of polyurethane, respectively.

Experiment B In a mixer, 75% by weight of wollastonite powder (FW200 from Pargas, Finland) and 25% of particulate solid polyester of such particle size that 80% of the particles have a size of less than 70 > , were mixed. The energy applied through the mixing softened the polyester particles to such an extent that part of them adhered to the wollastonite particles.

Experiment C Flocculation in various systems.

Flocculation experiments were performed with the following two recipes: Recipe No. 1: 70 g cardboard (2% aqueous suspension, beaten to 380SR) 10 g polypropylene particles, particle size below 100 U 30 g wollastonite/polyester material, polyester content 75%, prepared as described in Experiment A 30 g wollastonite/polyester material, polyester content 65%, prepared as described in Experiment A.

30 g wollastonite/polyester material, polyester content 55%, prepared as described in Experiment A.

Recipe No. 2: 70 g cardboard (2% aqueous suspension, beaten to 380SR) 10 g polypropylene particles, particle size below 100 U 30 g wollastonite/polyester material, polyester content 75%, prepared as described in Experiment A 30 g wollastonite/polyester material, polyester content 65%, prepared as described in Experiment A 30 g wollastonite/polyester material, polyester content 55%, prepared as described in Experiment A 104 g wollastonite powder.

The above suspensions were used in a concentration of 0.2% in water.

The experiments were performed in a 1000 ml graduated cylinder as follows: 1. Measure 1000 ml suspension.

2. Add flocculating agent.

3. Shake thoroughly.

4. Allow to stand on table, start timing.

5. Withdraw sample (at surface) and measure zeta potential and pH.

6. Record time (t40,)) when "precipitate" passes 400 ml line.

7. Record time (t2()o) when "precipitate" passes 200 ml line. If 200 ml line is not passed within 10 minutes, the volume of the precipitate is measured.

FLOCCULATION EXPERIMENTS WITH RECIPE 1 Zeta potential, Flocculation agent t400 t200 % Transmission millivolts pH Remarks Negative control 2:10 6:40 rather turbid -26.4 5.5 0.4% alum 6:40 half-clear -30.9 6.0 0.5% AC 6:40 half-clear -30.5 6.0 0.4% alum + 0.5% AC 2:15 7:20 half-clear -25.3 5.5 0.4% alum + 0.5% AC + 0.5% silane 2:10 6:30 rather clear -29.2 5.0 0.4% alum + 1.0% AC 2:40 205 ml clear, 91% -15.6 5.5 0.4% alum + 2.0% AC 2.36 205 ml clear, 89% -13.9 6.0 1.0% alum + 1.0% AC 2:07 7:40 clear, 87% -14.7 6.0 0.4% K-alum + 1.0% AC 2:20 8:20 clear, 82% -21.5 6.0 0.4% K-alum + 1.0% AC 2:03 7:40 clear, 86% -20.5 5.0 (after 10 minutes) 0.4% K-alum + 1.0% AC + 0.5% silane 1:55 6:20 clear, 85% -21.3 5.5 0.4% alum + 0.25% 829.8 Hercufloc clear, 93% + 6.3 6.0 very fast AC : Prodefloc AC, SIlane: Silan A1100 Hercufloc 829.8: polyelectrolyte, water soluble cationic polymer, polyacrylamide.

FLOCCULATION EXPERIMENTS WITH RECIPE 2 Zeta potential Flocculation agent t400 t200 % Transmission millivolts pH Remarks Negative control rather turbid, 68% -27.6 6.0 0.4% alum + 1.0% AC 1:30 clear, 90% - 7.5 5.0 h = 105 ml 0.4% alum + 0.25% 829.8 Hercufloc clear, 87% +13.3 6.0 very fast 0.25% 829.8 Hercufloc half-clear, 82% +14.5 6.5 very fast 0.4% alum + 0.25% N/2M 0:30 1:15 half-clear, 77% -19.8 7.0 very fast 0.4% alum + 0.25% N/2M + 0.5% AC 0:25 AC 0:25 1:10 half-clear, 83% -16.5 6.5 very fast 0.4% alum 0.25% AX-Special 7.0 0.4% alum + 0.25% A7 0:32 1:00 7.00 very fast 0.4% alum + 0.25% A7 + 0.5% AC 0:26 0:50 88% -17.9 7.0 very fast 0.4% alum + 0.25% C1 clear, 96% + 3.6 6.0 very fast 0.25% C1 0:27 clear, 96% + 2.6 7.0 very fast 0.125% C1 0:26 clear, 95% - 6.0 7.0 0.25% C4 0:36 clear, 97% +18.1 5.5 very fast 0.25% C8 0:25 clear, 97% + 7.4 6.0 0.25% C6 0:30 clear, 98% + 9.7 6.0 N/2M: Prodefloc N2M: polyelectrolyte, water soluble, high molecular anionic polymer flocculant AX-Special: polyelectrolyte, water soluble anionic polymer flocculant A7: polyelectrolyte, water soluble anionic polymer flocculant C1: Prodefloc C1, polyelectrolyte, water soluble, high molecular cationic polymer flocculant C4: Prodefloc C4, polyelectrolyte, water soluble, high molecular cationic polymer flocculant C8: Prodefloc C8, polyelectrolyte, water soluble, cationic polymer flocculant C6: Prodefloc C6, polyelectrolyte, water soluble, high molecular cationic polymer flocculant FLOCCULATION EXPERIMENTS WITH RECIPE 2 Zeta potential, Flocculation agent t400 t200 % Transmission millivolts pH Remarks Negative control rather turbid, 68% -27.6 6.0 0.4% alum + 1.0% AC 1:30 clear, 90% - 7.5 5.0 h = 105 ml 0.4% alum + 0.25% 829.8 Hercufloc clear, 87% +13.3 6.0 very fast 0.25% 829.8 Hercufloc half-clear, 82% +14.5 6.5 very fast 0.4% alum + 0.25 N/2M 0:30 1:15 half-clear, 77% -19.8 7.0 very fast 0.4% alum + 0.25% N/2M + 0.5% AC 0:25 1:10 half-clear, 83% -16.5 6.5 very fast 0.4% alum + 0.25% AX-Special 7.0 0.4% alum + 0.25% A7 0:32 1:00 7.0 very fast 0.4% alum + 0.25% A7 + 0.5% AC 0:26 0:50 88% -17.9 7.0 very fast 0.4% alum + 0.25% C1 clear, 96% + 3.6 6.0 very fast 0.25% C1 0:27 clear, 96% + 2.6 7.0 very fast 0.125% C1 0:26 clear, 95% - 6.0 7.0 0.25% C4 0:36 clear, 97% +18.1 5.5 very fast 0.25% C8 0:25 clear, 97% + 7.4 6.0 0.25% C6 0:30 clear, 98% + 9.7 6.0 Experiment D.

0.7 g Fintex 577, an "irreversible" cationic tenside of the type quarternary ammonium compound, was mixed with 100 ml of water, and 10 g of a powder poymer material consisting of 55% polyester applied on 43% TiO2/2% BaSO4, particle size distribution 0.1 - 30 , was added. The resulting suspension was allowed to stand for 10 minutes.

Thereafter, the aqueous phase was filtered off, and the polymer material was dried in an oven at about 60"C. The resulting polymer material coated with the irreversible tenside was added to 1.5 liter of an 1.5% suspension of cellulose fibers in water. It was evident that a considerable attraction between the cellulose fibers and the polymer material was obtained, as the particles of the polymer material flocculated together with the cellulose fibers. The resulting suspension was applied on a sieve, 100 mesh. The flocculate was retained on the sieve, and the water passing the sieve was substantially free of polymer particles.

In the Examples given below percentages are by weight unless indicated otherwise and terms not previously defined have the following meaning: Newspaper: Cellulose pulp prepared by heating old newspapers.

Cardboard: Cellulose pulp prepared by beating waste cardboard.

Sulphate: Sulphate cellulose pulp.

Sulphite: Sulphite cellulose pulp.

"SR: Schopper Riegler degree.

Wollastonite FW50: Wollastonite powder having a particle size of 1 - 500 Il, from Pargas, Finland.

Wollastonite FW200: Wollastonite powder having a particle size of 1 - 200 U from Pargas, Finland.

Synopal: Synopal (a synthetic mineral made from sand, dolomite, chalk, and aluminiumcontaining mineral) dust, particle size below 100 .

Slag fiber, glass fiber Rockwool: In all cases fibers having a diameter of 5 U logarithmically distributed down to 1 U and up to 30 , length from 1 mm up to 10 mm, predominantly about 3 mm.

Polyester: Polyester powder from Emser Werke, Switzerland, 70% of the particles having a size below 80 Il, the rest up to 200 U.

Polyester on TiO2/BaSO4: A commercial product from Pulvercoat, Germany, consisting of 55% of polyester applied on 43% of TiO2/2% of BaSO2, particle size 30 - 80 U.

Polypropylene: Particle size below 100 .

Epoxy polyester: From Emser Werke, Switzerland, 80% of the particles have a size below 70 Il, the remainder have a size of up to 200 ,u.

PVC: 80% of the particles have a size below 70 > , the remainder have a size of up to 200 U.

Urethane: Isonate 123 P (caprolactam-blocked polymeric isocyanate), the Upjohn Company, Kalamazoo, Michigan.

Copolyamide: Gril-tex 2P, melting temperature 120 - 1300C, a copolyamide with monomeric units of polyamide 12, polyamide 6 and polyamide 6.6, from Emser Werke.

Particle size below 80 > .

Berol 373: A non-ionic tenside consisting of an alkylene oxide adduct based upon normal primary alcohol; the tenside has hydrophilic (water soluble) character. The product is a clear liquid with 100% active content. From Berol Kemi AB, 44401 Stenungsund 1, Sweden.

"Triton" [Registered Trade Mark] CF10 may also be used instead of Berol 373.

"Triton" CF10: Alkylphenoxypolyethoxyethanol from Rohm & Haas, Philadelphia, USA.

"Nopco", [Registered Trade Mark], NXZ: Antifoaming agent containing non-ionic emulsifier, from Nopco Chemical Company, 60 Bark Place, New Ark, New Jersey, USA.

Fintex 577: A cationic tenside of the type quaternary ammonium compound from Berol Kemi AB. This tenside is of "irreversible" character, that is, after having become attached to its substrate (single layer structure), it cannot be re-dissolved with water.

Sand: Danish beach sand, particle size below 300 .

Cement, white: White Portland cement; Blaine: 3400 cm2/g; 77 - 83% C3S.

Polyethylene, crosslinked: A produce from Sigma, 67.3% of particles have size above 200 U.

PVC 3107/11/2: A plasticized product (32% plasticizer + carbon black).

PVC 3085/92A/1: A non-plasticized (rigid) product.

PVC 3085/91A/3: A plasticized product (32% plasticizer).

PVC O-VI-107-1: A non-plasticized (rigid) product.

PVC 5 WSW 67-951: A plasticized product.

The above PVC products are all from British Industrial Plastics Limited, Darlington, England.

Retention: Assessed visually.

Water absorption, %, day: Percentage weight increase after about 24 hours.

Examples I - 23 were all performed on a laboratory "sheet former", and all components were mixed in the vessel of the sheet former prior to starting the suction. The holding time in the vessel after mixing all components except the flocculating agent was about 5 minutes, the flocculating agent being added immediately prior to sheet formation. After sheet formation, the sheets were dried in a ventilated oven, and thereafter, the sheets were heat-treated in a heated press.

Example No. 1 2 3 4 5

Newspaper, %, 60 "SR 30 Cardboard, %, 40 "SR 25 Sulphate, %, 35 "SR 15 15 8 Sulphate, %, 35 "SR 15 Wollastonite FW50, % 65 Wollastonite FW200, % 40 50 65 65 Polyester, % 30 25 20 20 20 Silan A 1100, % of inorg. 0.5 0.5 Dynasylan GLYMO, % of inorg. 0.5 Volan, % of inorg. 0.5 (as hereinbefore defined) Triethylamine % of inorg. 0.5 Prodefloc AC, % 0.5 0.5 0.5 0.5 0.5 Sheet weight g/m2 2000 2000 2000 2000 2000 Retention, % . . . . . . . . . 97-98 . . . .. . . . . . pH (adjusted) 6 6 6 6 6 Drying temperature, C 80 80 80 80 80 Heating temperature, C 190 190 190 190 190 Heating time, minutes 4 4 4 4 4 Heating pressure, kg/cm2 40 40 40 40 40 Density, g/cm3 1.1 1.2 1.3 1.3 1.2 Annealing residue, % 41 51 66 66 66 Tensile strength, kg/cm 30 42 42 43 43 Water absorption, %, day 10 8 4 4 5 Water vapour absorption 6 5 2 2 3 at 85% relative moisture, % Example No. 6 7 8 9 10

Cardboard, %, 40 "SR 25 25 25 25 25 Wollastonite FW50, % 50 50 50 50 50 Polyester, % 25 20 20 Polypropylene, % 5 Epoxy polyester, % 25 PVC, % 5 Urethane, % 25 Silan A 1100, % of inorg. 0.5 0.5 0.5 0.5 0.5 Prodefloc AC, % 0.5 0.5 0.5 0.5 0.5 Sheet weight, g/m2 2000 2000 2000 2000 2000 Retention, % . . . . . . . . . 97-98 . . . .. . . . .. . . . pH (adjusted) 5.5 5.5 5.5 5.5 5.5 Drying temperature, C 80 80 80 80 80 Heating temperature, C 190 190 200 190 200 Heating time, minutes 4 4 4 4 4 Heating pressure, kg/cm2 40 40 40 40 40 Density, g/cm3 1.3 1.3 1.3 1.3 1.3 Annealing residue, % 51 51 51 51 51 Tensile strength, kg/cm 42 45 50 36 48 Water absorption, %, day 9 6 9 8 6 Example No. 11 12 13 14 15

Cardboard, %, 40 "SR 20 20 20 20 20 5 Wollastonite FW200, % 60 Synopal, % 60 8 Mineral wool, slag fibers, % 60 10 Mineral wool, glass fibers, % 60 Mineral wool, Rockwool, % 60 15 Polyester, % 20 20 20 20 20 Silan A 1100, % of inorg. 0.5 0.5 0.5 0.5 0.5 Prodefloc AC, % 0.5 0.5 0.5 0.5 0.5 20 Sheet weight, g/m2 2000 2000 2000 2000 2000 Retention, % 97 97 98 98 98 25 pH (adjusted) 5.5 5.5 5.5 5.5 5.5 Drying temperature, "C 80 80 80 80 80 Heating temperature, "C 190 190 190 190 190 30 Heating time, minutes 4 4 4 4 4 Heating pressure, kg/cm2 40 40 40 40 40 35 Density, g/cm3 1.3 1.3 1.1 1.1 1.1 Annealing residue, % 61 61 61 61 61 Tensile strength, kg/cm 42 38 52. 68 50 40 Water absorption, %, day 7 6 8 10 7 Example No. 16 17 18 19 20

Cardboard, %, 50 "SR 20 20 20 20 20 Wollastonite FW50, % 43 43 43 43 43 * Mineral wool, slag fibers, % 15 15 15 15 15 Ho Polyester, % 20 20 20 17 15 Polypropylene, % 3 5 Aluminum hydroxide, % 1 1 1 1 1 Ammonium phosphate, % 1 1 1 1 1 Berol 373, % 0.1 0.1 0.1 Nopoc, NXZ, % 0.2 0.2 0.2 0.2 Silan A 1100, % of inorg. 0.5 0.5 0.5 0.5 0.5 Triethylamine % of inorg. 0.4 0.4 0.4 0.4 0.4 Prodefloc AC, % 0.4 0.4 0.4 0.4 0.4 Sheet weight, g/m2 2000 2000 2000 2000 2000 Retention, % . .97-98. pH (adjusted) 5.5 5.5 5.5 5.5 5.5 Drying temperature, "C 80 80 80 80 80 Heating temperature, "C 190 190 190 190 190 Heating time, minutes 4 4 4 4 4 Heating pressure, kg/cm2 40 40 40 40 40 Density, g/cm3 1.3 1.3 1.3 1.3 1.3 Annealing residue, % 60 60 60 60 60 Tensile strength, kg/cm 44 44 46 46 47 Water absorption, %, day 7 7 6 6 6 Example No. 21 22 23

Cardboard, %, 50 "SR 20 20 25 Wollastonite FW50, % 43 44 35 Mineral wool, slag fibers, % 15 Polyester, % 15 0 o - Polyester on TiO2 and BaSO4 36 Copolyamide, % 5 PVC, % 40 Aluminum hydroxide, % 1 Ammonium phosphate, % 1 Berol 373, % 0.1 Nopco, NXZ, % 0.2 Silan A 1100, % of inorg. 0.5 0.5 Triethylamine, % of inorg. 0.4 Prodefloc AC, % 0.4 0.5 Prodefloc C1 % 0.1 Sheet weight, g/m2 2000 2000 Retention, % .... 97-98 . pH (adjusted) 5.5 5.5 5.5 Drying temperature, C 80 80 80 Heating temperature, C 190 190 190 Heating time, minutes 4 4 4 Heating pressure, kg/cm2 40 40 40 Density, g/cm3 1.3 1.2 Annealing residue, % 60 59 Tensile strength, kg/cm 52 40 Example 24 In a full scale experiment on a paper making machine, the mixture used consisted of 400 kg cardboard cellulose, beaten to 25 SR, 500 kg of polyester material consisting of 55% polyester applied on 43% TiO2/2% BaSO4, particle size 30 - 80 , 100 kg wollastonine FW200 and 5 liters of silan A 1100. Prodefloc AC was continuously added in an amount corresponding to 0.5%, calculated on the dry matter of the recipe, and the point of addition for Prodefloc AC was in the tube from the overflow chest to the inlet chest. The wire of the paper making machine was from Nordiskafilt AB, "V tvira" quality 6050/0 (double plastic wire), and wire volocity was 8 meters/minute.

The cellulose was beaten in the normal way, and the polyester was added together with the wollastonite powder in the machine chest (100 m ) which was equipped with a powerful stirrer. The temperature of the cellulose pulp was about 50 C, and its dry matter content was 2%. The dry matter content in the final sheet prior to rolling up was 50 - 55%. Sheet weights from 1200 g/m2 to 2000 g/m2 were prepared. An investigation of the final material by means of surface microscope showed that the wollastonite was evenly distributed in the sheet. The wire side did not have any greater content of wollastonite than the upper side. A sample of this cardboard-like composite material was shaped and dried in corrugated shape in a profile dryer, and the dried material was compressed into corrugated panels in a smaller die at a pressure of about 8 kg/cm2 at a temperature of about 1700C for 15 minutes. The resulting panel is excellently suited for use as a roof coating panel.

Example 25.

In a "Bakelite" [Registered Trade Mark] die, three layers of the cardboard-like composite material prepared according to Example 24 were arranged on top of each other.

At a pressure of 200 kg/cm2 and a temperature of 1700C for about 15 minutes, there was prepared an excellent dish with sharp contours, good die release properties and a material character resembling that of glass fiber-reinforced polyester.

Examples 26-36 These Examples were performed on a pilot plant paper making machine. The same procedure as in Examples 1 - 24 was followed, that is, in the machine chest, cellulose pulp, polymer material and any inorganic additives were mixed, and the processing aids stated, except that the flocculation agents, were also added at this stage. The flocculating agents were added immediately prior to the transfer of the suspension to the wire. The data for these Examples appear from the Table below in which the various designations have the same meaning as in Examples 1 - 23. The barium sulphate material is barium sulphate powder having a particle size below 100 U the brass powder has a particle size below 200 U Instead of Hercufloc 829.3, also, for example, Hercufloc 853 may be used.

Example No. 26 27 28 29 30 31 32 33 34 35 36

Straw cellulose, 25 15 %, 40"SR Sulphate, 80 20 17 20 15 20 10 %, 35"SR Sulphite, 90 15 %, 35"SR Thermomechanical 95 cellulose fibers, %, 40"SR Glass fibers, % 60 55 Slag fibers, % 51.5 20 20 10 15 Rockwool fibers, % 60 o Wollastonite 15 10 10 FW200, % Example No. 26 27 28 29 30 31 32 33 34 35 36 Synopal, % 10 Barium sulphate, % 25 10 10 Brass powder, % 22 23 25 25 Polyester on 20 30 18 18 12 20 15 TiO2/BaSO4 Prolypropylene, % 5 20 Copolyamide, % 10 20 3.5 10 Ammonium poly- 0.2 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 phosphate Ammonium hy- 1.5 droxide Triton CF10 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Silan A 1100, 0.4 0.6 0.6 0.6 0.6 0.7 0.7 0.7 0.7 % of inorganic Nopoc NXZ, 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 % of inorganic Alum, % 2.1 2.1 2 0.5 0.4 0.5 0.5 0.4 0.5 0.6 0.6 Prodefloc AC 0.5 0.3 0.5 0.6 0.7 0.4 0.5 0.5 0.4 0.6 0.5 Hercufloc 829.3 0.05 0.1 Prodefloc CL 2 0.5 While the materials prepared according to Examples 1 - 24 all show a relatively hard and plate-like character, subsequent to the release of the film-forming properties of the polymer, the materials prepared according to Examples 26 - 28 show a pasteboard-like character subsequent to the film-formation of the polymer, but they show a better wet-strength than ordinary pasteboard. The materials prepared according to Examples 29 32 show a character like non-woven fabric (fleece), whereas the materials prepared according to Examples 33 - 36 are suitable for use as friction materials, especially for brake linings.

Instead of brass powder, bronze powder could be used, and instead of polyester applied on the inorganic carrier, non-carrier-containing polyester particles may be used and also epoxy polyester could be used. Instead of polypropylene, polyethylene can be used.

Example 37 In the same manner as described in Examples 26 - 36, a composite material was prepared using 20% sulphate cellulose and 80% of a polymer material consisting of Rockwool fibers having a coating of phenol formaldehyde resin polymerized to an extent of 80%, the resin constituting 3 - 4% of the polymer material. The resulting product is suitable for preparing hard boardlike panels and shaped articles by heat treatment at a pressure of 200 kg/cm In another experiment, the same resin-covered Rockwool fibers were used in an amount of 85%, the amount of sulphate cellulose being 15%. A similar material suitable for the same purpose as above was obtained.

Example 38 In the manner described in Examples 26 - 36, a composite material was prepared from the following recipe: About 200 liters of water 1350 g of sulphate cellulose 300 g of polyethylene powder (SA65), particle size 300 - 500 0.2 % (3 g) of Prodefloc C1.

The sheet weight of the product was 228 g/m2. After drying, the product has slightly uneven, pasteboard-like character, and after releasing of the film-formation of the polymer under a pressure of 50 kg/cm2 for about 2 minutes, a uniform, parchment-like material of a good waterproof character was obtained.

Example 39 The procedure as described in Examples 26 - 36 was followed using the following recipe: About 200 liters of water 1350 g of sulphate cellulose 300 g of polypropylene (LM229), particle size 300 - 500 F 5 - 10% of a 1% solution of Prodefloc AC 0.2% (3 g) of Prodefloc C6.

The zeta potential of the resulting suspension was -6.0 millivolts, and the sheet weight of the product was 268 g/m2. The product resembled the composite material prepared according to Example 38.

Example 40 The procedure as described in Examples 26 - 36 was followed using the following recipe: 100 liter of water 675 g of sulphate cellulose 150 g of polypropylene (LM229) about 5 % of 1% solution of Prodefloc AC 0.2 % (1.5 g) of Prodefloc C6 1/2 ml of Silan A 1100.

The sheet weight of the product was 316 g/m2.

Example 41 The procedure as described in Examples 26 - 36 was followed using the following recipe: About 200 liter of water 1000 g of sulphate cellulose 1000 g of glass wool 800 g of polyester resin (Polyester-Lack, 861-0984) 0.11 % (1.65 g) of Prodefloc C1 0.89 % 1.35 g) of Prodefloc C4.

The suspension of water, sulphate cellulose, glass wool and polyester resin was initially run through a deflaker.

The pH of the suspension was 6.5, and the zeta potential was +4.6 millivolts. The sheet weight of the product was 330 g/m2.

Example 42 The procedure as described in Example 41 was followed using the following recipe: About 200 liters of water 500 g of sulphate cellulose 1500 g of glass wool 800 g of polyester resin (Polyester-Lack, 861-0984).

The above mixture was finely distributed in a deflaker.

Thereafter, 0.15% (2.25 g) of Prodefloc C1 was added.

The pH of the suspension was 6.5, and the zeta potential was from +4.0 millivolts to -9.2 millivolts.

The sheet weight of the product was 310 g/m3. The product is, as the product prepared according to Example 41, nice and uniform.

Example 43 The same procedure as described in Examples 26 - 36 was followed using the following recipe: About 200 liters of water 500 g of sulphate cellulose 1500 g of Rockwool fibers, to which mixture was added a mixture of: 800 g of grey epoxy powder (epoxy on 45% TiO2) 0.15% of Prodefloc C1 (2.25 g) 10 ml of Fintex 577 1 liter of water.

The ph was 6.5, and the zeta potential was +6.8 millivolts.

The sheet weight of the product was 432 g/m2.

Example 44 The procedure as described in the previous examples was followed using the following recipe: About 100 liters of water 75 g of cellulose fibers (old cardboard, 42"SR) 375 g of glass wool 519 g of polyester having a content of 35% of wollastonite 606 g of Wollastonite FW50 10 g of tenside WKT 15 ml of 1% Prodefloc C1.

The pH was 7.0, and the zeta potential was -10.1 millivolts.

Examples 45 - 54.

Examples 45 - 54 were all performed on a laboratory "sheet former" as follows: Cardboard cellulose was beaten, sand was added to the resulting pulp, and thereafter polymer was added, said polymer having been passed through a sieve (430 U) in wet condition, and the resulting mixture was stirred for 2 minutes at 1000 r.p.m. Flocculating agent was added, and the stirring was continued for 15 - 20 seconds at 200 - 400 r.p.m. After this flocculation, the batch was poured into a vessel of a sheet former and was stirred for approximately 1/2 minute, and the suction was started. After sheet formation, the sheets were dried in a ventilated oven and thereafter treated in a heat press.

Example No. 45 46 47 48 49

Cardboard, %, 50 "SR 20 20 20 20 20 * Sand, % 45 45 45 45 45 S PVC (3107/11/2), % 85; 80)* 75)* 70)* 65)* PVC (3085/92A/1), % 15 20) 30 35 335 Prodefloc C1, 0.125 0.125 0.125 0.125 0.125 % of inorg.

Sheet weight, g/m2 3000 3000 3000 3000 3000 Retention, % 100 100 100 100 100 Drying temperature, "C 60 60 60 60 60 Heating temperature, "C 250 250 250 250 250 Heating time, minutes 1/2 1/2 1/2 1/2 1/2 Heating pressure, kg/cm2 40 40 40 40 40 *Addition of 35% of a mixture of the two PVC's in the weight ration indicated.

Example No. 50 51 52 53 54

Cardboard, %, 50 "SR 20 20 20 20 20 Sand, % 45 30 45 45 30 Cement, white 30 15 15 30 Polyethylene, cross- 15 20 20 8 -linked, % PVC (3085/91A/3), % 85)" 85420 20 PVC (O-VI-107-1), % 10 15 15 PVC (5WSW67-951), % 10 Prodefloc C1, 0.125 2)** 2)** 2)** 2)** % of inorg. ) ) 0.125 0.125 0.125 0.125 Prodefloc N2M 1) 13 1) 1) Sheet weight, g/m2 3000 3000 3000 3000 3000 Retention, % 100 90 90 90 90 Drying temperature, "C 60 60 60 60 60 Heating Temperature, C 250 250 250 250 250 Heating time, minutes 1/2 1/2 1/2 1/2 1/2 Heating pressure, kg/cm2 40 40 40 40 40 * Addition of 20% of a mixture of the two PVC's in the weight percentage ratio indicated.

**Addition of a total of 0.125% of the two polyelectrolytes in the weight ration indicated. First, the two parts by weight of Prodefloc C1 was added, and thereafter, the one part by weight of Prodefloc N2M was added.

Example 55 A material for use as backing for polyvinylchloride flooring was made from cellulose fibers (20 - 40" SR) 20% glass wool 50% polyvinyl chloride (10 - 70 30%.

The cellulose fibers and the glass wool were defibrilated separately in a beater. (The glass wool was beaten up to 0.5% suspension in water with 0.01% of Prodefloc C1 added.

Stirring was limited to maximum 1 minute.) The suspensions were combined, and the polyvinyl chloride is added. Just before the inlet chest of the paper machine, 0.2% Prodefloc C1 was added, and the resulting flocculate was de-watered and the web was dried. The web is suitable for application of the polyvinyl chloride foam and the upper finishing coat of the flooring. The backing is able to suspend itself during the manufacturing, and the heat applied when combining the polyvinylchloride foam and upper finish bonds the backing intimately to the foam.

Example 56 Using the same procedure as in Example 55, a composite material was made from cellulose fibers 20% by weight glass wool 45% by weight PVC (3107/11/2) 80%) ) 35% by weight PVC (3085/92A/1) 20%) Example 57 Analogously to the procedure in Example 55, a composite material was made from cellulose 20% glass wool 45% cross-linking 35% polyethylene Example 58 Analogously to Examples 45 - 54, a material suitable for use as roofing panel was made from cellulose 20% by weight sand 45% by weight po

Claims (48)

1. Example 61 Analogously to Examples 45 - 54, a material suitable for use as a roofing panel was made from cellulose 20% by weight cement, white 20% by weight Sand 25% by weight PVC (3085/9lA/3) 85%) PVC (0-VI-107/1) 15%) 35% by weight WHAT WE CLAIM IS: 1. A process for preparing a composite material having a cellulose fiber structure in which the cellulose fibers are bonded together by hydrogen bonds, comprising preparing an aqueous suspension containing, in a non-flocculated state, a polymer material in the form of solid, discrete particles of fibers, having polymer at least at their surfaces, the polymer comprising one or more synthetic water-insoluble and water-nonswellable solid polymers which are non-sticky at room temperature and film-forming at temperatures above 80"C, and a cellulose fiber pulp; co-flocculating the polymer material and cellulose fibers by addition of a water-soluble synthetic polymeric polyelectrolyte flocculating agent, and immediately thereafter de-watering the resulting suspension to form a coherent material; and drying the coherent material under conditions which do not elicit the fusion of the polymer, the polymer of the polymer material being such that the polymer material remains in the form of substantially discrete particles or fibers upon drying.
2. 2. A process according to claim 1 comprising the further step of subjecting the dried material to heat and optionally to pressure to fuse the polymer.
3. 3. A process according to claim 1 or 2 in which an inorganic material in the form of mineral or metal particles or fibers is added to the aqueous suspension prior to co-flocculation.
4. 4. A process according to claim 3 in which the inorganic material comprises metal particles of brass, iron, zinc, aluminum, copper or bronze, or mineral articles of TiO2, iron oxide, wollastonite, kaolin, de-glassed glass (as hereinbefore defined, calcium carbonate, quartz, sand, silica, steatite, talc, aluminum silicate, a synthetic mineral comprising sand, chalk and dolomite, barytes, diatomaceous earth or amorphous SiO2.
5. 5. A process according to claim 3 in which the inorganic material comprises synthetic mineral fibers of glass wool, glass rovings, stone wool, slag wool, kaolin wool or calcium silicate wool or metal fibers of brass, copper, aluminum, bronze or iron.
6. 6. A process according to claim 5 in which is incorporated glass wool fibers as inorganic material and polyvinyl chloride as the polymer.
7. 7. A process according to any one of claims 3 to 6 in which is incorporated, as inorganic material, an inorganic binder.
8. 8. A process according to claim 7 in which the inorganic binder is cement or kaolin cement.
9. 9. A process according to claim 7 or 8 comprising subjecting the dried material to a heat treatment to fuse the polymer, optionally adding water to the material and thereafter allowing the inorganic binder to harden.
10. 10. A process according to any one of the preceding claims in which the polymer material is added to the cellulose pulp as an aqueous suspension containing a surface-active agent.
11. 11. A process according to any one of claims 3 to 10 in which the inorganic material is added to the cellulose pulp as an aqeuous suspension.
12. 12. A process according to any one of the preceding claims in which the zeta potential of the suspension to be flocculated is maintained at -20 to +20 millivolts.
13. 13. A process according to claim 12 in which the zeta potential is maintained at -10 to +10 millivolts.
14. 14. A process according to claim 13 in which the zeta potential is maintained at -5 to +5 millivolts.
15. 15. A process according to any one of the preceding claims in which fibrous material is incorporated as the polymer material or as inorganic material, and the fibrous material is defibrillated by agitating it in aqueous suspension with an added polyelectrolyte.
16. 16. A process according to any one of the preceding claims in which the polyelectrolyte is added in an amount of 0.005 - 2% by weight, calculated on dry weight of the constituents of the suspension to be flocculated.
17. 17. A process according to any one of the preceding claims in which the composite material comprises at least 2% by weight, based on the composite material, of polymer material.
18. 18. A process according to any one of the preceding claims in which the polymer material comprises: 1) particles of polymer having a particle size of 1 - 500 ,u, 2) particles of an inorganic carrier coated with polymer, said particles have a particle size of 1 - 500 3) fibers of polymer, or 4) inorganic fibers coated with polymer.
19. 19. A process according to claim 18 in which the polymer material is in the form of particles 1) or 2) having a particle size of 1 - 200 p.
20. 20. A process according to any one of the preceding claims in which the polymer is a polyolefin, vinyl polymer, polystyrene, polyimide, polyamide, polyacrylate, ABS polymer, epoxy resin, epoxy/phenol resin, phenol resin, urea resin, melamine resin, polyester resin, melamine-polyester resin, cross-linked acrylic resin, silicone resin or polyurethane resin or a copolymer thereof, or a synthetic vulcanisbale elastomer.
21. 21. A process according to claim 20 in which the polymer is polyvinyl chloride, polyvinyl acetate or a copolyamide.
22. 22. A process according to claim 20, in which the polymer is the synthetic vulcanisable elastomer SBR.
23. 23. A process according to any one of claims 1 to 19 in which the polymer is a cross-linked synthetic polymer and a thermoplastic synthetic polymer or a cross-linked synthetic polymer, powdered bitumen or bitumen emulsion and a thermoplastic synthetic polymer.
24. 24. A process according to claim 23 in which the cross-linked synthetic polymer is a polyester and the thermoplastic synthetic polymer is polyethylene, polyvinyl chloride or polypropylene.
25. 25. A process according to any one of claims 1 to 19 in which the polymer is a combination of a non-plasticized and a plasticized polymer.
26. 26. A process according to claim 25 in which the polymer is a combination of a non-plasticized polyvinyl chloride and a plasticized polyvinyl chloride.
27. 27. A process according to any one of the preceding claims in which the polymer material comprises particles of an inorganic carrier material coated with polymer, the carrier material being metal particles of brass, iron, zinc, aluminum, copper or bronze, or mineral particles of TiO2, iron oxide, wollastonite, kaolin, de-glassed glass (as hereinbefore defined), calcium carbonate, quartz, sand, silica, steatite, talc, aluminum silicate, a synthetic mineral comprising sand, chalk, and dolomite, barytes, diatomaceous earth or amorphous SiO2.
28. 28. A process according to claim 27, in which the particles of polymer material comprise a polyolefin or an epoxy, polyester, acrylic or polyamide resin applied on TiO2 particles, the polymer being 40 - 90% by weight of the total weight of the polymer material.
29. 29. A process according to any one of claims 1 to 26 in which the polymer material comprises polymer-coated inorganic fibers, the fibers being mineral fibers of glass wool, glass rovings, stone wool, slag wool, kaolin wool or calcium silicate wool, or metal fibers of brass, copper, aluminum, bronze or iron.
30. 30. A process according to claim 27 or 29 in which the polymer constitutes 2 - 40% by weight of the total weight of the polymer material.
31. 31. A process according to claim 30 in which the carrier is particulate and the polymer constitutes 5 - 40% by weight of the total weight of the polymer material.
32. 32. A process according to claim 30 in which the carrier is fibrous and the polymer constitutes 2 - 20% by weight of the total weight of the polymer material.
33. 33. A process according to any one of the preceding claims in which the polymer of the polymer material is in the form of a cellular structure formed by the polymer containing a blowing agent, which, under the temperature conditions at which fusion of the polymer takes place, simultaneously foams up the polymer to yield a cell structure.
34. 34. A process according to any one of the preceding claims, in which the composite material contains an anti-moisture impregnating agent which is a wood-protecting oil, a bitumen emulsion, or a paraffin emulsion, or an oil emulsion containing a cationic tenside which is decomposed at temperatures of about 100"C.
35. 35. A process according to any one of the preceding claims, in which the composite material after dewatering is extruded to form an extrudate.
36. 36. A process according to any one of the preceding claims in which the dewatered and dried product is granulated and the polymer is then fused.
37. 37. A process according to any one of claims 1 - 34 in which the composite material is prepared in the form of a laminate comprising layers of composite material.
38. 38. A process according to claim 37 in which the material has a higher content of the polymer in surface layers than in interior layers.
39. 39. A process according to any one of the preceding claims, in which a composite material is prepared from a suspension comprising 15 - 40% by weight of the cellulose fibers, 15 40% by weight of the polymer, and 20 - 70% by weight of inorganic material.
40. 40. A process according to claim 1, substantially as hereinbefore described with reference to any one of the Examples.
41. 41. A process according to any one of claims 1 - 39 in which the composite material prepared is formed into a roof panel by application of heat and pressure.
42. 42. A process according to claim 41 in which the composite material comprises about 20% by weight of cellulose fibers, 40 - 50% by weight of inorganic particulate material and 30 - 40% by weight of polymer.
43. 43. A process according to claim 42 in which the inorganic particulate material is wollastonite or sand having a particle size below 300 U.
44. 44. A process according to claim 41 substantially as hereinbefore described with reference to any one of Examples 1 to 24, 45 to 54 and 58 to 61.
45. 45. A process according to any one of claims 1 - 39 in which the composite material is prepared is formed into a flooring backing web by application of heat and/or pressure.
46. 46. A process according to claim 45 in which the composite material comprises 15 - 25% by weight of cellulose fibers, 40 to 60% by weight of glass wool or stone wool, and 30 - 40% by weight of polymer.
47. 47. A process according to claim 45 substantially as hereinbefore described with reference to any one of Examples 29 to 32 and 55 to 57.
48. 48. A composite material or a product comprising a fused polymer when obtained by a process as claimed in any one of the preceding claims.