FI69333C - FOERFARANDE FOER FRAMSTAELLNING AV FORMADE PRODUKTER - Google Patents

Description

. ro. <44 NOTICE OF PUBLICATION, Λ 7 - - ^ UTLÄGG NIN GSSKRIFT 69 333 C (45) Patents granted

Patent uoJ.'alat 10 01 10CG '(51) Ky.lk. * / Lnt.CI. * D 21 J 1/00 SUOMI FINLAND (21) Patent application - Patentansöknlng 791560 (22) HakemlspäivS - Ansökningsdag 16.05 * 79 (F » ) (23) Start date - Giltighetsdag 16.0 5.79 (41) Become public - Blivit offentlig 26.11.79

National Board of Patents and Registration NS Date of Initiation and Publication—

Patent- och registerstyrelsen '' Ansökan utlagd och utl.skrlften publlcerad 30.09.85 (32) (33) (31) Pyydetty etuoikeus - Begärd prlorltet 25.05 * 78

Sweden-Sweden (SE) 7805693-1 * (71) (72) Stein Gäsland, Dreyersvej 29, 2960 Rungsted Kyst, Denmark-Danmark (DK) (7 ^) Harry V. Norden (5 ^) Method of production of shaped articles - Förfarande for fram- ställning av formade produkter ______

The present invention relates to methods of making shaped articles, in particular to methods of making shaped wood fiber products in which the articles are made from aqueous suspensions of fibers.

Methods of production of conventional wood fiber products such as - in its thinnest form "paper" - in its medium-thick intermediate form "cardboard" and - in its thickest form "particle board" mainly comprise the dispersion of cellulose, ground pulp or chips in water at very low concentrations. In order to obtain a uniform distribution of the fibers so that they can be made into paper and board of satisfactory quality, flocculation of the fibers must be avoided. This requires that the fibers be dispersed in water in a weight ratio of 200: 1.

The water is removed - by drying with a wire cloth - then by pressing - and finally by heat drying

Paper and board have been produced on the same principle for soon 180 years.

The treatment of large volumes of water and the environmental problems associated with the dewatering of the 2 69333 parts that cannot be recycled have made the paper industry large heavy units, which must be able to use at least about 80% of their production capacity - day and year - to earn interest. large investments.

The reason for the high utility of wood fibers is their "innate" ability to form chemical compounds - the so-called hydrogen bridges - with each other, when the dry matter content approaches about 70% during drying. Thus, the final product is mechanically durable. This durability can be further improved by adding suitable binders. The use of binders becomes more topical the more the use of recycled fibers is made, as this strengthens the strength properties compared to fresh fibers. The binders can be added evenly to the pulp before the nonwoven mat is formed, or the binder can be added in the subsequent surface treatment. Both methods have their limitations - In pulp addition, the binder is added to the process at the time when the fiber dilution is highest. In that case, expensive ionic active binders must be used so that the binders adhere to the fibers and do not disappear with the water. Other additives do not give the best possible results - partly due to poor retention, partly due to high dilution.

- Surface treatment methods are effective in improving the surface properties of products, but not in improving internal strength properties. In the more common method, when improving the strength properties, the paper passes through an adhesive press. After the glue press, it is dried by heat treatment to a dry matter content of about 95%. The glue press can be. only light, low-viscosity liquids should be treated, which means that the viscosity of the binder must be reduced, which also reduces the bond strength. In addition, it is not possible to reach a concentration higher than about 13%, with the result that the sheet is so moist that the dewatering that consumes onn-qia as a stem must be carried out once more.

Prior to the first drying, the amount of water is usually 7,000 1 / ton of paper produced, and 1 in sizing is about s00 '; j per 69333 tonnes, so the total amount of water to be evaporated will be 2i times the amount of dry matter.

As a result of these limitations, amounts of binder in excess of 1/20 relative to the fiber are rare.

Known proposals for solving the problem of large amounts of water are: Small increase in concentration 1. Using foam formation, the amount of water can be calculated n.

100 times the amount of fiber.

2. Swedish patents 355615, 366787, 362458 and 385029 describe the so-called high consistency sheeting, which makes it possible to lower the water / fiber ratio to 25. A higher consistency gives an uneven fiber distribution.

Completely dry sheeting

Completely dry sheeting of the cellulose fibers occurs when the so-called "Non-woven": a. See, e.g., U.S. Patent 3,575,749. At the same time, however, the innate ability of cellulose to form hydrogen bonds cannot be exploited. As a result, large amounts of liquid synthetic binders such as styrene butadiene or acrylic latexes must be added.

On an industrial scale, no processes have been implemented between the two extreme options: extremely low concentration and completely dry production.

However, the present invention solves the above-mentioned problems concerning the large amount of water and the limitations in the amount of additives in a new way and provides a method for preparing shaped articles starting from aqueous suspensions of fibers. This method is characterized in that after any dewatering and before shaping, one or more hydrocolloids are added to the suspension in order to completely bind the water. The amount of water in the formulation is about twice the amount of dry matter, which is a significant improvement over? 00 times for conventional paper and board production.

According to the invention, it is best to use cellulose, ground or chip fibers, synthetic fibers, e.g. polyester, polyamide or acrylic, and mineral fibers, e.g. asbestos.

According to the invention, it is most suitable to use starch, a starch derivative, dextrin as the hydrocolloid. polyvinyl alcohol, a cellulose derivative such as carboxymethylcellulose and hydroxyethyl cellulose, an animal protein such as casein, a vegetable protein such as soybean, a vegetable glue such as guar gum and rye rye and rye seed and powder of locust bean gum, algae, , etc. or from root vegetables such as potato or tapioca.

The invention is particularly advantageous at the fiber and coiloid concentrations shown in the curves of Figures 7-16.

The hydrocolloid may be added dry, dissolved in water or dispersed in water or other solution.

According to the invention, the shaping can be carried out at different temperatures and even at high pressure. In the shaping step, expansion can also be performed by releasing gas or water vapor

According to the invention, it is suitable to carry out the molding by extrusion or injection molding using machines of the same type as used in the plastics industry, coating with machines of the same type used in the plastics industry, the paper and board industry and in the .

The fiber suspension obtained after the addition of the hydrocolloid consists of a homogeneous plastic, solid paste of fiber, water and colloid. This paste has completely different properties from the fiber suspensions normally used in the manufacture of fiber products.

If such a conventionally prepared fiber suspension is used for extrusion, injection molding, rolling or pressing, the actual dewatering takes place instead of the forming process, and in the case of extrusion or injection molding. dried fiber clogs the nozzles. It is completely impossible to draw conventional fiber suspensions> ΐ ». · Η because the suspensions do not have any internal cohesive forces.

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Fortunately, the colloid is both - a process aid that binds water in the design and prevents the fibers from flocculating together - a functional end product aid that acts as a binder and thus increases mechanical strength.

More hydrocol1 is required to bind water than is commonly used in conventional methods. As can be seen from the experiments, the appropriate amount of coiloid is approximately 1/3 of the amount of fiber. The invention has thus eliminated the limitations on the amount of additives mentioned at the beginning.

The invention is described in more detail below with reference to the accompanying Figures 1-16. The figures illustrate examples, as the invention can certainly be applied to many different hardware options, as well as the various combinations between fibers and colloids are innumerable.

Figure 1. shows how fiber 1 can be dissolved in water in a fiberizer 2 with an efficient mixer 3. Mixing separates the individual fibers. The dissolution can be divided or supplemented by known steps such as disintegration, deinking defibering and grinding. The resulting suspension is transferred to filter 4 for concentration, also in a known manner. The addition of water 5 to the process can best be used to purify the fibers as a filter before any further concentration of the fiber in the crusher 6. The water 7 separated in the filter can be re-conveyed to the defiberer, possibly after purification. Impurities that come with the fiber can be removed by known dissolution processes in the fiberizer itself or on the way to the filter. After the water has been removed to the desired concentration level, hydrocollolide 8 is added, which is mixed by kneading 9, after which the paste is ready for shaping. The shaping is performed in a special device or possibly by extrusion directly from the kneading device. The desired temperature 10 can be set in the design.

Figure 2. shows the design with the extruder 1. The desired temperature is set in the extruder by heating or cooling. High temperature allows, as shown below, higher concentrations. First, drying is performed by radiation or convection 2, the residual extruded pattern of which is placed in steam-heated molds 69333. The hood above the rotating mold boxes, which recovers heat from the released steam, is not shown in the figure. When the mold boxes differ from each other 3, the production line is divided into sections of the desired size, and when the drying step is completed, the piece is removed, for example with compressed air 4. Before a new paste is placed in the mold boxes, these can be cleaned and otherwise prepared. Figure 2 shows the extrusion of the figure, but in fact a wide, flat die of the extruder can also be used to form flat sheets, which are dried and post-treated in the same way as paperboard.

Figure 3. shows the intermittent extrusion into a molded part, or as this operation is called in the plastics industry - "injection molding". The upper part of the mold body is firmly attached to the mouthpiece 1 of the extruder, and the lower part 2 is also used to transfer the material to the drying compartment 3. The hood above the drying compartment for recovering the released steam is not shown. The material is removed from the drying device, eg with compressed air 4. During drying, the material has shrunk, which is why it is compressed to the correct size.

By mixing additives that release gas - most often hydrogen, carbon dioxide or nitrogen - or extruding the paste at a temperature higher than 100 ° C and atmospheric pressure so that water vapor is released faster than in conventional drying, porous products can be obtained. Expansion can also be accomplished by foaming. A cover package with a hard outer shell and a soft shock-absorbing inner surface can be produced by holding two different surfaces of the molded article at different temperatures. "Sandwich" structures with an expanded core portion and integral outer surfaces can be made by cooling both outer surfaces during shaping while the core retains its temperature. The main principles of foam manufacturing can be ignored.

According to the invention, building elements such as plates can be manufactured, e.g. as shown in Figure 4. The paste 1 comes from the outlet box 2 and is leveled on a forming table 4 between two, for example, paper cover layers. The paste can possibly be pre-dried on a shaping table, e.g. by means of radiation. The main drying is carried out in a rather long drying oven 5, where the hydrocolloid partially migrates towards the surface and forms a paste in the cover layer. Finally, the manufacturing line is divided into suitable sizes 6. Through the expansion step, as described above, the desired compromise between durability, thermal insulation and sound insulation can be achieved.

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Figure 5 shows an example of coating a paste 2 made according to the invention. In this way, fibrous products can be combined, for example, with a plastic film 1.. After pre-treatment, the paste 3 is smoothed and dried 4.

The material formed according to the invention, while still moist and thus formable, can be placed in molds in which e.g. plates are made.

The articles made according to the invention can also be combined with other materials after molding, e.g. by printing on a decorative film or decorative printing, and a clear lacquer based on e.g. acrylic, PVC or polyurethane can then be added on top of this. The box made according to the invention can be covered with decorative paper or lined with a water-resistant material.

As mentioned, a larger increase in moth is required to bind water than is normally used to improve the strength properties in paper and board production. This large amount of binders can be considered a disadvantage of the present invention, as it is generally considered that all additives cause additional costs to the process. In this case, however, this is not the case, which is simply explained by the fact that the most common colloid - starch - costs about the same as cellulose. If, for this reason, cellulose is replaced by a mixture of starch and cheaper, weaker fiber, then the raw material costs per tonne become shark-less and the starch compensates for the reduced strength properties. The only type of paper or board that can be compared in rigidity and hardness to products made in accordance with the present invention is the so-called "waste paperboard", in the first stage of the manufacture of which paper is made, which in the following stage is glued together in several layers. Smooth test sheets with a basis weight of 4,00-1200 g / m 1; was made according to the invention and compared by stiffness measurement to a scrap board on the market. It turned out that only the most expensive grades of glue board were able to achieve the same stiffness properties - with the same weight per square meter - as the present invention using newsprint as a raw material and starch as a colloid. Such rigid glued board must be made from butter-containing pulps which cost about 14 (H) mc / square i, while according to the invention Amal 1a is obtained from one rigid board, e.g. by extruding a paste, yes »; The composition is 23% newsprint waste FIM 200 / tonne and H% starch (see Figure 11) l .200 FIM / tonne or an average raw material cost of FIM 69333 / tonne 4603 / tonne. Ko. the invention makes it possible to reduce the raw material costs by about 1/3 of normal compared to conventional methods and to maintain the stiffness properties.

Corrugated board is a preferred and rigid form of packaging invented by Albert L. Jones in 1871, U.S. Patent 122023. The stiffness of the board relative to the amount of material used has been improved by making the center hollow and the surfaces tight. The most important quality feature is the high stacking height of full corrugated boxes, which is achieved by allowing the folds in the walls of the box to run vertically, and that rigid paper is used in this corrugated layer. fluting. However, in the production of base paper - inner fluting and outer liners - it has not been possible to implement this orientation of strength properties. In paper production, it is possible to align the fibers in the longitudinal direction of the machines, but not transversely. In corrugated board mills, the base paper is treated as whole lines and and the corrugations become unfortunate across the stiffest parts of both the fluting and the liner. This is greatly exacerbated by the fact that corrugated board mills, when corrugated, ruin some of the rigidity that paper mills have acquired in fluting.

These disadvantages are eliminated if k.o. the invention is used in corrugated board production e.g. as shown in figure 6: - The fibers in the liners 2 are oriented in the same direction as the corrugations - Fluting is pressed in the form of a paste according to the invention from a wide extruder die 1 with a wavy pattern.

- Stiffening fluting is not folded after shaping.

Before both liners 2 are attached, pre-drying with radiation 3 can be performed. The main drying is done in a long drying min in the same way as in conventional corrugated board production 4. In conventional production, the corrugations run transversely, while the in the invention they can be placed longitudinally, as shown in cross-section 5. If the heating furnace is made inclined, the released steam can be removed by natural convection 11 a 6. i 69333

In drying, the colloid in the middle layer migrates outwards towards the line-thighs and glues the two layers together so that no glue needs to be added. Another important improvement is the possibility of a higher wet stiffness property in resin addition so that the starch content in the middle layer is higher than usual. Finally, economy should not be forgotten. As mentioned above, the raw material costs of the fiber products are according to the invention about FIM 460 / ton. By way of comparison, corrugated board mills now buy their paper raw materials for about FIM 2,000 / tonne.

The production of corrugated board can, of course, be represented in many other ways than shown in Figure 6. According to the invention, for example, liners can be made using wide, flat extruder mouthpieces.

Due to the high concentration of the binder, the invention is of particular interest for the production of products in which a rigid, hard woody feature increases the marketing value of the final products, such as in the form of a box or carton. The invention is also particularly interesting when it is desired to produce hollow objects, because the conventional methods, which have to start from a smooth sheet, are difficult to manufacture. On the raw material side, the invention is of particular interest for the reuse of old newspapers. This feedback fiber is not - due to its low strength properties and drying rate - attractive compared to other reuse methods - and is therefore inexpensive. As will be shown later, newspaper waste paper requires less colloid to bind water than long fibers.

In cases where it is not desired to have a rigid and hard product but instead softer and tougher end products, the hydrocollate can be combined with a synthetic binder such as, for example, styrene-butadiene, acrylic or vinyl acetate latex.

In cases where an even stiffer product is desired than when using only a hydrocolloid as a binder, the hydrocolloid can be combined with other binders, such as cement.

Natural resins and synthetic resins can be added to prevent water absorption. To improve the wet strength, for example, urea formaldehyde resin, melamine formaldehyde resin, etc. can be added. Other additives can be fillers such as kaolin and chalk, pigment 69333 such as titanium dioxide, and dyes and flame retardants.

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Drying can be facilitated by the addition of a filler which makes the paste porous or by the addition of substances which absorb water, e.g. calcined gypsum or cement.

The test was performed with an injection molding machine, model Demag Stubbe S 55 d, usually intended for plastic materials. The crusher mouthpiece of the machine was 3 mm in diameter. There was no difficulty in squeezing the paste from this mouthpiece into a mold with a casting opening of 250 mm and a material thickness of 2 mm. Leaving a 0.3 mm gap between the two parts of the mold, a film having a thickness of 0.2 mm after drying was pressed. The prerequisites for trouble-free injection molding and film extrusion were: - Complete water binding in the paste. Insufficient addition of hydro-colloid caused drying in the mouthpiece, which was clogged by the fibers.

- Adequate fluidity. At too high concentrations, interfaces could be observed in the shaped material.

In the experiments, boxes resembling cigar steps were made, which, after drying, resembled more wooden than cardboard steps.

In order to determine the concentrations and colloids as well as the suspended material that could be used, a whole series of experiments were performed.

The minimum and maximum amount of colloid in which the invention is useful was measured in the laboratory for various fiber cones. Two criteria were selected for this work:

Criterion for maximum amount of hydrocolloid: A so-called Haake consistometer was used. This is a thermostatically controlled through hole with a piston through which a 2 mm hole is drilled. The consistometer is used in the plastics industry to measure the viscosity of thermoplastics after melting.

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The viscosity is calculated from the formula:,? = ——. K s where i] = viscosity Pascal x seconds G = load in kiloponds t = time sec s = measuring distance mm K = hole device constant = 2.5

The criterion chosen was 10,000 Pascal seconds, as in the plastics industry this is considered to be relatively high, but still unproblematic.

Criterion for the minimum amount of hydroko 11 oi di a:

The same Haake consistometer was used to determine how much colloid was needed to make a homogeneous tape without the tendency to dry as it discharged out of the nozzle. The dewatering tendency is reflected in the free (shimmering) water. he surface.

According to these two criteria, the angular curves in Figures 7-16 are drawn. The fiber consistency is on the abscissa and the coiloid concentration on the ordinate - both in weight percent of the whole paste. The final separation up to 100% is water.

The Mi name criterion gives the left curves of the angle curves and the maximum criterion the right, and the area between the branches is thus the most useful invention.

In Figures 7-9, the fiber raw material is newsprint feedback fiber and the compression temperature is 20 ° C. The colloids are koM = cold water1 soluble oxidized maize starch,

Amijel 5, from CPC p = natural potato starch G = Quar gum, Super Co 1 U Powder, from General Mills oM = oxidized maize starch, Amisol 05594, from CPC M - natural maize starch CMC = carboxymethylcellulose, Majol PS 6, Uddeholmic i; VA · - polyvinyl alcohol i, Covol 9930, CPCrsta r 'AA = polyacrylamide, GP 999, WR Granan 12 69333

It can be seen, for example, from Figure 8 that at a fiber consistency of 16%, at least 7% of the starch is required as a colloid to bind water. As the amount of colloid is increased, the paste thickens so that at 10% it is so thick that the possibility of compression without a particularly strong extruder can be doubted.

Natural corn starch and ordinary cold water-soluble starch gave the same curve M. In potato starch, it appeared that ordinary cold water 1 soluble type met the requirements of the criteria with smaller increments than natural starch and the peak of maximum concentration shifted to the left. However, after vigorous kneading, the viscosity and water bonds were restored to the same level as in natural potato starch. Only the curve P for natural starch is drawn in the figure.

Figures 10-12 still show old newspapers as a fibrous raw material, but the extrusion temperature has been raised to 85eC. The colloids are P = natural potato starch CMC = carboxymethylcellulose, Majol PS 6, Uddeholm G = guar gum, SuperCol U Powder, General M i11 s M = natural corn starch A = alginate, Protanal H, Protan & Fagertunista oM = oxidized corn starch, Amisol 05594, from CPC PVA = polyvinyl alcohol, Covol 9930, from CPC PAA = polyacrylamide, GR 999, from WR Grace The tips of the curves show how high fiber consistencies can be further worked based on the selected criteria. Comparing the corn-starch curves M in Fig. 8 and Fig. 11, it can be seen that an increase in the compression temperature of 20 -> 85 ° C causes an increase in the maximum fiber concentrations of 20 -> 28%. The colloidal concentration at 85 ° C and the maximum fiber concentration are 6%, so that the amount of water becomes 66%, i.e. about twice the dry matter content.

Extrusions were also performed at temperatures higher than 85 ^ 0, which is the highest temperature in the diagram. However, due to evaporation, it was not possible with the available measuring equipment to measure the criteria for pi pe i tä nti n i m i rna.il i s i 1 le and maxima i s i 1 le koi looid maar i 1 le. The Fräs compression test was performed on a 140 ° C paste consisting of 41 X of newspaper pulp as a fiber and 6% of natural potato starch as a colloid so that the ratio of water content to dry matter was less than 1 pound. The energy demand for drying can thus be the invention to be lower than in conventional paper and board manufacturing. Potato starch was added to the pulp as undissolved and heat coagulated immediately before pressing. Squeezing through a 2 mm thick mouthpiece went smoothly. After passing through the opening of the mouthpiece, the paste during the release of steam expanded into a belt-like network with a specific gravity of 0.2 kg / dm3 after drying compared to 0.8 kg / dm at normal compression temperatures of 100 ° C.

Figure 13 still shows newspaper waste paper as the fibrous raw material, but instead of using pure hydrocolloid, ordinary wheat flour with a degree of grinding of about 78% has been used. Presses were performed as usual at temperatures of 20 ° C and 85 ° C. The curves show e.g. that the maximum criterion concentration is lower for wheat flour than for starches.

Figure 14. shows a fibrous newspaper waste paper a and a colloid of natural potato starch, but before measuring the criterion points, 4% of 50% styrene-butadiene latex, OL 675, from Dow. In this figure, the difference between the amount of water and the amount of retained fibers and colloid obtained from the diagram is 98% water, while in all other diagrams the difference is almost 100% as water. The temperature was 20 ° C. Comparing the potato-starch curve in Fig. 7, it can be seen that the latex increases the water retention capacity and makes the paste more flexible, causing the lower criterion curve to move down and the maximum fiber consistency to the right.

In Figure 15, the old raw material is unbleached kraft paper sacks and the colloid is natural corn starch. Compression was performed as usual at 20 ° C and 85 ° C. The experiment showed that this fiber sulphate pulp, based on its more sensitive dewatering capacity and also higher flocculation tendency, required more colloid than newsprint pulp to meet the minimum criterion, with the "left corner branch" rising higher. This is revealed by comparing the curves M in Figures 8 and 11.

Figure 16. shows the criteria for extruding blends in which the fiber is newsprint and the colloid is casein. The casein used was Polish 30 mesh nitric acid casein. To facilitate the dissolution of the casein, it was added as a dry mixture containing 53% casein, 1% sodium carbonate (Na, CO 2) and 3% moisture. The figure in Figure 16 shows 14 69333. sodium carbonate read as colloid.

Extrusions through the Haake Consistometer and other design were more comfortable in the middle of these two different branches of the curve, and not too close to the peak of the maximum dry matter content. In the vicinity of the minimum criterion and close to the top, the paste and the final product had a granular structure - grinding less than in the mass.

To draw the criterion curves, the amounts of fiber and colloids are shown on a dry matter basis. The moisture introduced into the system with the fiber or colloid is calculated as water - within the accuracy of the concentration measurements. However, the amount of water in colloids other than starch and wheat flour was so small that it was excluded from the calculations.

The following is a set of experimental data.

The fibrous raw material was dissolved in hot water at a concentration of 2X and with vigorous stirring. The suspension thus formed was dewatered through a sieve with a sieve density of 3/4 mm and compressed between the hands to a dry matter content of 10 and 35 X.

In order to obtain reproducible curves, it proved very important to always use the same temperature - time in the preparation and storage of the pastes before measuring the criterion points. Different methods were used for hot water and cold water soluble hydrocollo de Ilie.

Method for hot water soluble colloids:

About 200 g of the fiber suspension and the dry-mixed colloid are combined in an attempt to achieve the desired criterion and placed in a sealed glass jar and oven at 110 ° C for 10 minutes. The temperature of the oven is reduced to 95 ° C, at which temperature the sample is allowed to stand for 30 minutes. The glass jar is then opened and, after rapid mixing of the contents, the viscosity and water binding at 85 ° C are measured. The rest of the sample should be 60 min. in a sealed glass jar - now (for many temperatures) after which these same two criteria are measured at 20 ° C. If the test is allowed to stand for more than 60 minutes at room temperature, a lower water binding value and a higher viscosity are obtained.

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The curves of corn) starch, oxidized corn starch, potato starch, wheat flour, polyvinyl alcohol, alginate, CMC and guar are drawn after such a measurement, although the latter three colloids are actually cold-water soluble.

Method for cold water soluble colloids:

Cold water-soluble colloids clump easily when added ϊ to the fibrous slurry. In order to avoid the resulting clogging of the orifice of the conistor, the powder must be sprinkled very evenly, carefully and in small portions on the surface of the fibrous slurry, and immediately after each addition a very vigorous effort must be made. Also in connection with this method, n.

200 g of suspension in each sample. Viscosity and ve-water binding measurements were performed at 20 ° C immediately after the last addition of the coiloid dose. The rest of the sample was allowed to be 90 min. in an oven at 95 ° C before measuring the two criteria also at 85 ° C.

This method was used for cold water soluble corn starch, cold water soluble oxidized corn starch, cold water soluble potato starch, and casein and polyacrylamide. If the method were used for CMC and guar, about 1% more colloid would be needed than with the hot water soluble method, probably on the grounds that the colloids would be incompletely soluble without heating.

Finally, a number of experiences with drying paste samples are presented.

If the drying was carried out in an oven at 105 ° C so that the 1 mm thick paste cakes were allowed to dry and dry on the untreated iron surface, difficulties may arise in the subsequent removal from the iron surface. Experience shows that removal is easier by adding a large amount of colloid and using the most efficient colloids as the water tower, i.e., when working in: areas with naxi micrometer, Figures 7-16.

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If, instead, the specimens were heated on a hot plate, the detachment problem was greatly reduced, and when cut through the dried test sheets, it could be seen that the hydrocolloid on the surface was enriched on the surface facing the hot plate. This confirms the recent claim that large numbers of moths facilitate removal. The higher number of moths on the surface of the test sheet from which the heat was introduced can be explained by the fact that the colloid travels with the water towards the heat generating iron plate where the water evaporates and the hydrocolloid remains because it cannot migrate back and forth with the steam.

If the drying was performed in a Teflon-coated metal mold, there were no difficulties in removing the pre-dried fiber products.

Claims (9)

1. Process for the production of molded products starting from aqueous suspensions of fibers, characterized in that, only after any dewatering, during kneading or such processing of the pulp, one or more hydrocarbons are added in such large amount that the remaining water is completely bonded, after which the products are formed by extrusion, injection molding, coating, rolling, pressing, drawing etc. and then dried or cured in another way. 2. A method according to claim 1, characterized in that wood fibers, e.g. fibers of cellulose, abrasive or spin, synthetic fibers e.g. polyester, polyamide or acrylic fibers and organic fibers such as asbestos or glass fibers. 3. A process according to any one of claims 1 or 2, characterized in that hydrocolloid is used e.g. starch from any plant species, starch derivative, dextrin, polyvinyl alcohol, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, animal protein such as casein, vegetable oil such as guar gum, carbohydrate protein or hydrochloric acid meal and vegetable flour meal polyacrylamide and flour from cereals such as wheat, oats, shrimp, etc. or from root plants such as potatoes and tapioca. 4. A process according to any one of claims 1-3, characterized in that the concentrations of fibers and coils which can be used are those produced by the curves in Figures 7 - 16. 5. A process according to any one of claims 1-4, characterized in that the hydrocolloid is added to the fiber suspension dry, dissolved in water or dispersed in water or other liquid. Method according to any of claims 1-5, characterized in that the molded product is expanded due to gas formation, released No or foaming.