WO1994016145A1

WO1994016145A1 - Composite material based on cellulose and manufacturing the same

Info

Publication number: WO1994016145A1
Application number: PCT/FI1994/000007
Authority: WO
Inventors: Rabbe Max Rafael Back
Original assignee: Rabbe Max Rafael Back
Priority date: 1993-01-08
Filing date: 1994-01-07
Publication date: 1994-07-21
Also published as: FI930073A0; FI930073A

Abstract

The invention relates to a solid and rigid composite material, consisting of a cellulose-containing, reinforcing main ingredient and a bonding agent, and possibly additives. Said reinforcing main ingredient is chopped cardboard and/or paper, at least half thereof being single or corrugated cardboard with the surface weight over about 130 g/m2 and the size of chopped particles varying mainly in the range 5 to 5000 mm2, and the positions accidental. The bonding agent is an adhesive known in itself in the art, the dry matter content whereof in the composite material being below about 20 per cent by weight. The mixed mass has been compressed prior to the adhesive curing so that the volume of the complete composite material is substantially smaller than the volume of the mixed ingredients thereof in free space.

Description

Composite material based on cellulose and manufacturing the same .

The present invention relates to solid and rigid composite material, consisting mainly of a cellulose-containing rein¬ forcing main ingredient and a binding agent, and potential additives. The invention also relates to a method and a means for producing said material.

Both within the industry and commerce, a great variety of pallets are used whereon goods to be transported are stacked and the load is kept coherent e.g. by means of shrink-wrap¬ ping thereon. In Finland, such pallets have in general been made of wood and they are used for a long time by being re¬ turned either empty or loaded in different ways to the owner. For said purpose, various follow-up systems are used in different companies in Finland to prevent losses of pallets. The costs per pallet per transport can in this manner be kept reasonable although the timber pallet in itself is quite costly. The follow-up and returning of pallets causes, however, additional costs. In a great many of countries no pallet return system has been organized, neither any kind of follow-up system, but the pallet in said systems is typically non-returnable in those countries, i.e. it is destroyed after one use. If the pallet is made of timber as in Finland, destroying it involves costs, because of which a special refuse disposal fee must be paid in certain countries like Germany. This fact and the high price of the wooden pallet causes that use of thereof is highly unprofitable. As a solution to the above problem the manu¬ facturing of disposable pallets from cardboard and es¬ pecially from corrugated cardboard has been started. Said pallets are produced so that the plane and the edges of the pallet are bent from large pieces of corrugated board and the legs of the pallet are made by glueing on top of each other pieces of a precisely given size cut from corrugated board. Said pallet is far more lighter than a wooden one, thus making a much higher useful load possible. In addition, said pallet is because of the material easy to dispose of because of and particularly, such pallet can be utilized e.g. as raw material in pulp industry, on the condition that the bonding agents used therein are appropriate. With said arrangement, for instance greater refuse disposal fees can be avoided, at least to some extent. A drawback related to said pallet is, however, that it must be produced entirely from virgin corrugated cardboard since the legs have to be glued together from corrugated cardboard pieces with accurately cut dimensions. Furthermore, the legs have to be glued individually into one in a kind of jig, thus slowing down the manufacturing process. Said details described above increase the price of the product.

It is conceivable, in theory, that e.g. the legs of a dis¬ posable pallet were be produced from an article based on a prior art compound material, i.e. composite material, in order to make the structure less expensive. E.g. several types of cellulose-based composite materials exist and they are commonly used. One of the most common ones is a material made from sawdust or chipped wood and from formaldehyde glue, known more commonly as chip board. Said material is relatively heavy in weight and expensive, because of which it is not very well appropriate for producing disposable products. In addition, the glue used therein makes the re¬ cycling of a product of that material difficult. The chip board cannot be used in any way e.g. as a raw material in the pulping process. Disposal by means of burning is ques¬ tionable, therefore, the refuse fees become high. Thus, the chip board is not appropriate for use as construction ma- terial for pallets.

The objective of the present invention is therefore to pro¬ vide a material which would be sufficiently solid and rigid for various purposes, and at least useful for structural a- terial in various parts of disposable pallets, and parti¬ cularly as legs, which should be relatively light in weight to be produced in great quantities. A second aim of the in¬ vention is a material which is easy to dispose of without detrimental effects, and which is particularly well suited for recycled use, for instance as a raw material in pulp in¬ dustry. A third aim of the present invention is a material which is appropriate for use as raw material in pulp indus¬ try without any particular further processing. A fourth aim of the invention is a material which should to as great extent as possible be made from a material which otherwise would go into waste. A further aim of the invention is a material which in no phase of production or use would cause environmental problems.

The problems described above can be solved and the aims thus disclosed are attained by means of a composite material ac¬ cording to the invention, which is characterized in what is stated in the characteristic features' part of claim 1. The method of the present invention for manufacturing said ma¬ terial is characterized in what is defined in the character¬ istic features• part of claim 5, and the means for manufac¬ turing said material is characterized in what is defined in the characteristic features* part of claim 17.

An advantage of the invention is that the material taught thereby can be produced from paper and/or cardboard material otherwise thrown into waste, and that the material, after the actual utilization, can be employed as a raw material in the pulping process. The composite material according to the invention is therefore excellent for circulation. Since starch adhesive is advantageously used in the material, no environmental detriments come about in any phase of the process because of the bonding agent or the dissolvent. An advantage of the production method of the invention is that continuous-actingly dimensioned products can be manufactured therewith, that is, the shape or size of the material will not be changed in the course of the process, e.g. for the reason that this process is a so-called dry-method. The means of the invention includes the advantage that it is simple in structure, neither does it require any excep¬ tionally costly structural parts which are difficult to produce.

The invention is described below in detail, referring to the accompanying figures.

Fig. 1 presents a phase diagram of the method of the present invention.

Fig. 2 presents the means of the invention in top view as a section along plane A-A of Fig 3A.

Figs 3A and 3B present a cross-section of the means of the invention along plane B-B of Fig. 2 with the compression die in open; respectively, closed position.

Figs 4A and 4B present two embodiments of the mould of the invention for producing a U-shaped, respectively hollow, composite material blank with square cross-section in longitudinal horizontal II and vertical I images and end image III.

The compound or composite material according to the in¬ vention mainly consists of chopped cardboard and/or paper as a reinforcing ingredient, and of an adhesive or equivalent used as the binding agent. At least about half of said chopped material is, according to the invention, chopped cardboard, being either of chopped corrugated cardboard or single cardboard, so that such a material is considered as cardboard in which the surface weight is over about 130 g / m². The size of the chopped particles is, according to the invention, over about 5 mm², e.g. 2 x 2.5 mm, and at most, about 5000 mm₂, e.g. about 7 x 7 cm. The maximum dimensions of the chopped particles is to a large extent determined by the size of the piece produced of the chopped material be¬ cause the particles have to be inserted into the compression mould. On the other hand, very small chopped particles gen- erate problems because of the curing of the material. The chopped particles are mixed with the adhesive and pressed to acquire the dimensions of the end product, whereby the chop¬ ped particles in the product are positioned in random, and the particles have, also due to the effect of compression, been deformed, and perhaps also their size may be different. This has resulted in homogeneous, that is, isotropic, ma¬ terial in different directions. The complete composite material contains relatively little of the adhesive. The dry matter content of the adhesive is at most about 20 per cent by weight, preferably in the range from 5 to 15 per cent by weight. The composite material according to the invention has been compressed from the initial materials into complete material so that the volume of the end product is substan¬ tially lower than the volume of the mixed ingredients there- of without compression, i.e. in free space. Such material is easy to work mechanically, and the strength thereof suffices for use e.g. as pallet components, and the volumetric weight thereof is reasonably low.

The size of the chopped cardboard and paper particles varies preferably within slightly more narrow limits than those de¬ scribed above, e.g. in the range 25 to 1000 mm², and prefer¬ ably of the order 1 cm x 1 cm - 2 cm x 2 cm. It also seems that at least half of the proportion of the cardboard is preferably corrugated board, in order to provide appropriate lightness, strength and rigidity, and workability.

In order to make the composite material of the invention circulatable and to keep the price thereof low, it is ad- vantageous to use starch adhesive as the adhesive, parti¬ cularly corn starch adhesive. If needed, wax can be added as an additive in the adhesive so that the moisture resistance of the composite material of the invention can be enhanced. For additives, also chemicals can be used to prevent the growth of bacteria or algae or other detrimental organisms.

The above-mentioned random position and formation of the chopped paper and/or cardboard particles can be obtained according to the invention by compressing in free space a relatively dry mixture of chopped materials and bonding agent into at least half of the volume it has in free space after mixing, but typically into about one fourth or one fifth of the initial volume of the mixture.

Fig. 1 gives a rough image of the steps of the method of the invention for producing a solid and rigid composite ma- terial. If needed, the cardboard and/or paper serving as the raw material is torn in advance in phase PI to make the chopping simpler. For the raw material, waste cardboard or paper, or equivalent can be used because the size of the raw material pieces is in no way significant. In phase P2, the carboard or paper is chopped into the above-mentioned order of magnitude of 5 to 5000 mm² or into a more preferred order of magnitude mentioned above. In the next phase P3 the chopped material thus obtained is advantageously heated to a temperature which is below the curing temperature of the adhesive being used, but substantially above the ambient temperature. In the instance in which starch adhesive, par¬ ticularly corn starch adhesive, is used for the adhesive, the preheating is taken to a temperature which is somewhat below about 50°C. By said procedure the curing of the adhesive will be accelerated in a heating phase M3 described below but it is not compulsory. The moisture content of the cardboard or paper used in the method of the invention is conventional, whereby the moisture of the cardboard or paper is on the average below about 25 per cent by weight, prefer- ably below about 15 per cent by weight. Under no circum¬ stances the paper or cardboard should be wet. Wet material is not appropriate for use in the method of the invention, for it must be dried to the above moisture in a manner known in itself but not described in detail in the present appli¬ cation. At least about half of the cellulose-containing main ingredient used is cardboard or equivalent, the surface weight thereof being at least about 130 g/m², preferably half thereof, i.e. a quarter of the entire cellulose-con¬ taining material is cardboard. If too thin initial material is used, the end product will be heavy and/or the curing of the adhesive becomes more difficult.

In phase LI, the starch adhesive, as in the present in¬ stance, is mixed in a manner known in itself in the art. In order to prepare the bonding agent, 1 part of starch, pre¬ ferably corn starch, and about 2 to 7 parts, preferably 3 to 5 parts, of water to be used as diluent are mixed, and pos¬ sibly additives, as described above. Said glue mass is mixed for one half to one hour at the same time as the temperature of the glue mass is maintained at about 20 to 35°C, prefer¬ ably at 25 to 30°C, for providing uniform glue mass.

For the mixing phase Ml of the adhesive and the chopped ma¬ terial, both chopped cardboard and/or paper material is dispensed in phase P4 and the adhesive in phase L2 so that the mass composed of the adhesive and the chopped material will contain adhesive to the extent that less than 50 per cent by weight of the diluent of the adhesive, i.e. water here, is included in the mass. It is preferred that the proportion of adhesive mixed with the chopped material is such that the diluent makes up less than about 40 per cent by weight of the composite mass, preferably in the range 13 to 30 per cent by weight. Using a diluent and glue content like this, the adhesive can be spread uniformly on the surface of the chopped particles within the mixture without making the chopped material too wet. The mixture Ml of the adhesive and chopped material is implemented for instance in a means compressing the composite mass so that chopped ma¬ terial not including any adhesive is let into a separate feed chamber, thereafter adhesive is sprayed through channels in the walls into said feed chamber, and the mass is compressed with a die into a compression chamber. Uniform feeding of the adhesive and the compression thereafter into the compression chamber generates such a motion in the com¬ posite mass which mixes the adhesive uniformly. It is also possible to mix the adhesive and chopped material mechan¬ ically in a separate mixer prior to being fed into the com¬ pression chamber. Said mechanical mixing may also be rein- forced by blowing air or the mixture can be implemented by fluidized bed method or any equivalent method. It is also possible to mix the chopped material and the dry bonding powder first, and moisten the premixture with a diluent, or vice versa.

In the next phase M2 the mixed composite mass thus obtained is compressed at a temperature substantially below the hard¬ ening temperature of the bonding agent, and in the above- mentioned manner at least into half of the volume which the mass has when mixed and in free space. The compression pressure of the composite mass is at least about 50 bar, preferably of the order 120 to 150 bar. Hereby, the volume of the mass reduces advantageously to about one fourth or fifth of the volume it had in free space. In said com- pression phase, the final dimensions of the composite mass quantity are essentially formulated. If the production is the same as production of single pieces, the dimensions of the final composite material piece are obtained, or, if a continuous or intermittent process is in question, the transversal dimensions of the final composite material blank are obtained.

In the subsequent phase M3, for the composite mass the di¬ mensions obtained in the preceding phase M2 are still main- tained, while the temperature is raised to a temperature above the curing temperature of the bonding agent, so that, thanks to the curing of the bonding agent, a desired ma- terial is obtained. When a starch adhesive such as the one in the present invention is in question, the temperature is raised above the gelling temperature of said bonding agent, to above of about 63°C, depending on the type of starch. As regards various makes of starch adhesives, the gelling temperature somewhat varies so that the above temperature should not be considered a limitation as such. When a different bonding agent is used, its curing temperature is probably entirely different. For said curing phase M3 of the bonding agent, the dimensions of the piece are maintained as they were during the compression phase M2, or approximately as such. A slight increase in volume will not cause any essential harm, and on the other hand, it is also possible to increase the compression somewhat for said heating or curing phase M3, particularly in a continuous or inter¬ mittent process as will be described below.

In the subsequent preheating phase M4 at least part of di¬ luent bound in the cured composite material is removed therefrom. For avoiding material damages, said diluent, or moisture when water is in question, is removed at a tempera¬ ture below the boiling point. The drying is accomplished in this manner merely to such diluent content of the composite material which makes the mechanical working of the material required in this phase feasible. For instance, when using starch adhesive, the piece is still quite soft after the curing phase M3 of the adhesive, so that the cutting of a composite material profile produced continuous or inter¬ mittent, and the other processing without damaging it is difficult. Hereby, part of the water is removed whereby the cutting and other treatment is again possible. Said after- treatment is marked as phase KM1 in Fig. 1.

The final drying of the composite material, i.e. evaporation of potential diluent, is accomplished outside the production apparatus proper in a storage volume within a few days thereafter as stage KM2, whereby the product acquires its final hardness and strength, whereafter the product is ready for final use KM3. Particularly said continuous or intermit¬ tent production into a profile or rod, plate or equivalent is a most advantageous production method, whereby the pro- duction rate can be raised to a high level. Semiproducts produced as produces of a continuous or intermittent process are cut in phase KM1 into either blanks or into final di¬ mensions for an end product.

Figs 2 and 3A, 3B present an embodiment according to the invention for a means with which the composite material described above can be manufactured as an intermittent process. In the present instance, the apparatus comprises a press section 1 for both composite mass mixing Ml and pressing M2, a heating section 2 for curing M3 the bonding agent, and a predrying section 3 for removal M4 of the diluent. In the present case, the press section 1 comprises both a compression chamber 4 and a feed chamber 5. As an extension to the compression chamber 4 the press section 1 comprises a contraction part 6 defined by mould 1 , which essentially determines the cross-section shape of the com¬ posite material piece. The compression chamber 4 is a cyl¬ indrical chamber being round or rectangular in cross- section, or different therefrom, at the other end thereof being provided a reciprocatingly moving compression die 8 providing the compression pressure in the feed direction SI of the composite mass. The compression chamber 4 includes said mould 7 in the end opposite to the die 8, which is substantially a conical mould in structure and basically similar to what is used in extrusion moulding. The com¬ pression chamber and the mould are thus extensions to each other in the compression direction SI and preferably co¬ axial.

As an extension to the press section 1 from the mould 7 on¬ wards a heating section 2 is provided in which the composite mass is heated to above the curing temperature of the bond- ing agent. The cross-sectional surface of the channel 9 of the heating section 2 is of the same order of magnitude as the initial cross-section 10 of the mould 7. The cross- section of the channel 9 may thus in principle be slightly greater than the initial cross-section 10 of the mould, or it may be somewhat convergent in the feeding direction SI therefrom. In other words, the channel 9 may at the first end lib be slightly smaller than at the entry end 11a corresponding to the initial cross-section 10 of the mould. Therewith the compression pressure can be controlled, which otherwise is determined by the friction between the com¬ posite mass and the walls of the chambers and channels of the apparatus. The length L of the heating section 2 is suf¬ ficient so that the adhesive in the compressed composite ma- terial would substantially be cured completely though it is necessary to pay attention not to allow the composite mass be overheated so that it is provided with appropriate motion velocity to have enough time to be heated in order to be cured throughout the cross-section area.

As an extension to the heating section 2 in the feed di¬ rection SI of the composite material, a predrying section 3 is provided, wherethrough drying air is circulated to make at least part of the glue diluent exit, such as water in the composite material. For said purpose, the cross-sectional area of the channel 12 of the predrying section 3 is some¬ what larger than the cross-sectional of the composite ma¬ terial when entering from the heating section 2, so that the drying air is provided space to circulate between the co - posite material rod and the wall of the channel 12.

In embodiment presented in the figures, a feed chamber 5 is associated with the compression section 1, being provided with a die 13 moving transversally to the feed direction SI of the composite mass, and at the feed chamber and typically thereabove with a feeding funnel 14 for the chopped card¬ board and paper material. In the present instance, the size of the feeding chamber 5 determines the dispensing P4 of chopped material. In the present instance, the walls of the feeding chamber 5 are provided with glue channels 15 for supplying glue into the chopped paper and cardboard material within the feeding chamber. The glue dispensing L2 is accomplished with an apparatus not shown in the figures, being any appropriate type known in the art.

The above described means operates as follows. After the feeding die 13 is pulled back in the direction opposite to the pushing direction S2, a material channel 16 from the feeding funnel 14 opens to the feeding chamber 5, whereby chopped the paper and cardboard material moves into the feeding chamber 5. Thereafter the feeding die 13 performs a work motion in the pushing direction S2 and at the same time, glue is supplied through the glue channels 15 among the chopped material. The feeding die 13 is pushed to the end position until the the material channel 16 closes. Thereafter the compression die 8 moves in the composite material feeding direction SI, whereby the material in the compression chamber 4 is compressed and thrust through the convergent part of the mould 7 and the initial cross-section area 10 shaped into the final dimensions onwards to the heating section 2. In the heating section 2 the com-posite mass is cured owing to the effect of the curing of the glue contained therein. Thereafter the composite material rod moves onwards to the predrying section 3 in which at least some of the potential diluent is removed. Said process is intermittently continuous in that the compression die 8 performs a work impact of a given length in direction SI, whereafter it moves in the direction opposite thereto, thus providing space in the compression chamber 4 into which the feeding die 13 through the feeding chamber 5 pushes more of the composite mass as the compression die is in said re- tracted position. When the feeding die has once again closed the material channel 16, the compression die 8 performs a new compression motion SI. In this manner the process is continued when said two die mechanisms operate alternately, whereby the composite material rod penetrates through the mould and the heating section a short distance at a time as an uninterrupted rod, profile, pipe or plate.

Fig. 4A presents a mould 7 provided with a mandrel 17 for pressing a U-shaped profile. Fig. 4B presents a mould 7 provided with a round mandrel 17 for producing a profile with a circular hole. There may, in fact, exist mandrels 7 of any shape.

A completely die-operated compression means is described above, but the compression section 1 may also be implemented with a compression screw for continuous compression of the composite mass. The feed chamber may also be provided with a feeding screw for continuous feeding of material. Also reci- procatingly moving feeding screws may be employed performing both the mixing and die compression. The chopped material and the glue can be mixed, not only in communication with the compression section, but also in a more or less detached mixer in which chopped paper and cardboard and the bonding agent are mixed using a mechanical mixing means, whereby the mixing can be intensified e.g. by air blowing. Also fluidized bed -type mixing is conceivable.

In order to maintain the compression chamber 4 and the mould 7 below the glue curing temperature, for instance the mould 7 can be provided with cooling members 19 and insulated it from the heating section 2 with a thermal insulation 18 therebetween. The heating of the heating section 2 is per¬ formed by means of heating elements 20, these being, inter alia, resistor or high-frequency heaters.

As a particular embodiment of the invention a material may be introduced in which no diluent is contained in the ad¬ hesive, whereby the adhesive is mixed with the chopped ma¬ terial dry, e.g. as a powder, and it melts in the heating process, thus binding the chopped particles together when cooling. The adhesive can be thermosetting plastic or thermoplast, or a melting resin obtained from natural sources, wax or equivalent. The composite material is now typically drier than the one described above so that there is no need for the diluent removal phase. The adhesives available do not favour recycling of the material, and they are relatively expensive, therefore, the methods described in the present description may be most often preferable. However, it is obvious that the material of the invention may also be produced in batches as individual pieces.

Claims

1. A solid and rigid composite material, mainly consisting of cellulose-containing reinforcing main ingredient and a binding agent and of potential additives, characterized in that said reinforcing main ingredient is chopped cardboard and/or paper, about half thereof containing single or corru¬ gated cardboard of over about 130 g/m² surface weight, and in which the size of chopped particles varies in the range 5 to 5000 mm², and the positions whereof being accidental, that the binding agent is an adhesive known in itself in the art, the dry matter content whereof in the composite ma¬ terial being below about 20 per cent by weight and that the volume of the composite material is substantially smaller than the volume of the mixed ingredients thereof in free space.

2. Composite material according to claim 1, characterized in that the size of the chopped cardboard and paper par- tides is in the range 25 to 1000 mm², preferably of the order 1 cm x 1 cm to 2 cm x 2 cm, and that at least about half of said cardboard proportion is corrugated cardboard.

3. Composite material according to claim 1, characterized in that the bonding agent is starch adhesive, preferably corn starch adhesive, and the dry matter content thereof in the composite material is in the range 5 to 15 per cent by weight and that, if required, the bonding agent contains wax or equivalent to enhance the moisture resistance, and/or an additive to prevent the growth of detrimental organisms.

4. Composite material according to claim 1, characterized in that the volume of the composite material is at most about half, and preferably about a quarter or fifth of the volume of the mixture of the ingredients in free space.

5. A method for producing solid and rigid composite material according to claim 1 using a dry method, said material consisting mainly of cellulose-containing con¬ solidating main ingredient and a binding agent, and potential additives, characterized in that (a) the cardboard and/or paper used as the reinforcing main ingredient is chopped essentially to size class of about 5 to 5000 mm²,

(b) for producing composite mass, such quantity of a bonding agent is mixed in said chopped material with which the proportion of the potential diluent of the bonding agent in the mass remains below about 50 per cent by weight,

(c) the composite mass is compressed at a temperature substantially below the curing temperature of the bonding agent at least to about half of the volume the mass has in free space,

(d) the composite mass is heated to a temperature above the curing temperature of the bonding agent by maintaining ap¬ proximately the dimensions produced in the preceding com¬ pression phase for making a composite material, and (e) from the cured composite material at least part of the diluent is removed, if needed, by means of ventilation.

6. Method according to claim 5, characterized in that at least half of the reinforcing main ingredients included in the mass is single or corrugated cardboard, the surface weight thereof being over about 130 g/m², that the size of the chopped ingredients is in the range 25 to 1000 mm, pre¬ ferably of the order of magnitude about 1 cm x 1 cm to 2 cm x 2 cm, and that the moisture of the paper and/or cardboard employed is on an average below about 25 per cent by weight, preferably below about 15 per cent by weight.

7. Method according to claim 5, characterized in that such an amount of bonding agent is mixed in said chopped material which the dry matter content of the bonding agent in said composite mass is below about 20 per cent by weight, prefer¬ ably 5 to 15 per cent by weight, and that the bonding agent used in said mass contains such amount of diluent with which the proportion thereof in the mass settles in a value below about 40 per cent by weight, preferably approximately in the range 13 to 30 per cent by weight.

8. Method according to claim 7, characterized in that for producing the bonding agent to be used in the composite mass, 1 part of starch, perferably corn starch, and 2 to 7 parts of water, perferably about 3 to 5 parts, to be used as diluent, and potential additives are mixed, and that in the course of mixing the temperature of the glue mass is main¬ tained in the range from 20 to 35 °C, preferably from 25 to 30 °C.

9. Method according to claim 5, characterized in that the chopped material used as the main ingredient is preheated prior to the mixing phase thereof and of the bonding agent to a temperature below the curing temperature of the bonding agent, but which is essentially above the ambient temperature.

10. Method according to claims 8 and 9, characterized in that when the bonding agent is starch adhesive, the pre¬ heating is implemented to a temperature somewhat below about 50 °C.

11. Method according to claim 5, characterized in that the mixing of said bonding agent and said main ingredient is im¬ plemented either in a device compressing the composite mass or alternately, by mixing mechanically or using the fluid- ized bed method, or equivalent method in a dispensing funnel or in a separate container or mixer.

12. Method according to claim 5, characterized in that the composite mass is compressed by at least 50 bar pressure, preferably by a pressure of order of magnitude 120 to 150 bar, whereby the volume of the mass advantageously reduces to about a quarter of what the mass has in free space.

13. Method according to claim 5 or 8, characterized in that in the curing phase of the bonding agent, the volume of the composite mass is maintained either the same as the volume of the preceding compression phase or alternatively the compression is slightly is increased by reducing the volume, and that when the bonding agent is starch adhesive, the temperature is raised to above the gelling temperature thereof.

14. Method according to claim 5 or 8, characterized in that the diluent is removed at least by the aid of ventilation, but possibly also by heating, whereby the temperature is maintained below the boiling point of the diluent, and that drying is accomplished in said manner only to such diluent content of the composite material wherewith the mechanical working required by the material is possible.

15. Method according to claim 5, characterized in that chopped cardboard and/or paper are/is made from waste and/or circulated material.

16. Method according to any one of claims 5 to 15, characterized in that the composite material is manufactured as a continuous or intermittent process into rod, plate, pipe, profile or equivalent, and after said diluent removal phase it is cut into pieces of requisite length.

17. A compression means for producing solid and rigid composite material according to claim 1, consisting mainly of cellulose-containing reinforcing main ingredient and a binding agent, and potential additives, said means including at least a compression chamber (4) , a contraction section (6) and a heating section (2), characterized in that the compression chamber (4) is provided with means (8) for producing requisite compression pressure in the composite mass; that the contraction section (6) is a mould (7) , substantially determining at least the cross-sectional shape of the composite material piece; that the heating section (2) is an elongated pipe or equivalent, the inner surface (9) whereof being at least approximately equivalent to the shape of the initial cross-section (10) of the mould; and that the compression chamber (4) , the mould (7) and the heating section (2) are positioned in succession as ex¬ tensions to each other in order to produce a continuously or intermittently operating means.

18. Compression means according to claim 17, characterized in that the compression chamber (4) includes either a reci- procatingly moving compression die (8) for intermittent or intermittently continuous compression of the composite mass or alternatively, a compression screw for continuous com¬ pression of the composite mass.

19. Compression means according to claim 17, characterized in that the mould (7) is tapering in the feed direction (SI) of the composite mass, that the cross-section of the channel (9) in the heating section (2) is the same as the initial cross-section (10) of the mould, or the cross-section of the heating section slightly contracts at the input end (11a) when travelling towards the output end (lib) in the mass supply direction (SI) , that a thermally insulating part (18) is provided between the mould and the heating section, and that the length (L) of the heating section (2) suffices re¬ lative to the motion velocity of the composite mass so that the adhesive at least mainly becomes cured by the length thereof, thus producing the composite material.

20. Compression means according to claim 17, characterized in that the compression section (4) and/or mould (7) have been cooled.

21. Compression means according to claim 17, characterized in that the means also includes a feed chamber (5) connected to the compression chamber (4), and a feed die (13) moving within said chamber, said die opening, during the backward motion, the material channel (16) from the feeding funnel (14) into the feed chamber (15) and during the forward feed motion (S2) closing said material channel, thus forcing the composite mass into the compression chamber.

22. Compression means according to claim 21, characterized in that from the feed funnel (14) the chopped cardboard and paper material is transferred into the feed chamber (4) , that the bonding agent is supplied into said chopped ma¬ terial through adhesive channels in the walls of the feed chamber (5) and that mixing of the chopped material and the adhesive into composite material is carried out in the feed chamber (5) and/or the compression chamber (4) by the aid of the motion of a feed die or screw, respectively, of com¬ pression die or screw.

23. Compression means according to claim 17, characterized in that for mixing the chopped cardboard and paper and the adhesive, the means comprises a mechanical mixer and/or air puhallus members for fluidized-bed type mixing or for in¬ tensifying the mixing either in the feeding funnel (14) or in a separate mixer located therebefore.

24. Compression means according to claim 18 or 21, characterized in that the compression die (8) , resp. screw, operates substantially in the feed direction (SI) of the composite mass and the operation direction (S2) of the feed die (13) forms a greater angle compared with said feed di¬ rection or it is preferably transversal to the feed direc¬ tion (SI) of said mass.

25. Compression means according to claim 17, characterized in that the means comprises furthermore a predrying section (3) as an extension to the heating section (2) , this being an elongated pipe or equivalent, the cross-section of said channel (12) being greater than the cross-section of the composite material emitted from the heating section and that the drying section (3) include means for making the drying air circulate along the surface or surfaces of the composite material.