SE421541B - PROCEDURE FOR MANUFACTURE OF FORMED PRODUCTS - Google Patents

Description

7805693-4 'In basically the same way, paper has now been produced and cardboard for almost 180 years. The management of the large water the quantities, as well as the environmental problems associated with them discharge of the part of the water that cannot be returned to process, has made the paper industry big, heavy units that must utilize at least approx. $ 80 of production the capacity - around the clock and all year round - to be able to return on large investments.

The reason for the great usefulness of wood fibers is theirs "innate" ability to form chemical compounds - so called hydrogen bridges - between each other when the water wiped off so that the dry matter begins to pass cs. $ 70.

This gives the electrical product a mechanical strength that can be further improved by adding binder.

The use of binders is becoming increasingly relevant as one switches to higher levels of recycled fibers, as these do not provide the same strength as the first ones use the fibers. The binder can be added homogeneously in stock before the fiber mat is formed or it can be used at a subsequent vt treatment. Both methods have however, its limitations: - In the case of stock addition, the binder is added to it point in the process where the fibers are present in the largest dilution, whereby expensive ionic agents must be used binder for it to adhere to the fibers in instead of disappearing with the water.

- Surface methods are effective for improving the products surface properties, but not for the improvement of the interior the strength. The most common method of strength enhancement is done by the paper passing through an adhesive press after heating with how dried to a dry content of approx. 95 É. The glue press can only handle thin, low- viscous liquids, so the binder must have a viscosity degraded, with reduced biud power as a result. In addition one cannot get higher in concentration than one. § 13 with the result that the sheet is moistened so strongly that it energy-intensive drying of water with heat 7805693-4 lost is performed once more.

As a result of these limitations are binder amounts over l / 20 of the amount of fiber rare.

Two completely different suggestions for solving the problem with those large vsttenmïngderna are already known: The Swedish patents 355615, 366787, 362458 and 385029, which so far has not been commercially available, describes so-called high-consistency nrkforming, med which it is possible to reduce the amount of water to 25 times the amount of fiber. Higher consistency gives uneven Iiber distribution.

- Completely dry srkforming sv oellulose fiber occurs for the manufacture of so-called "nonwoven".

U.S. Patent 3,575,749. However, the benefit of the innate property of cellulose to form hydrogen bridges, resulting in large quantities synthetic binders such as styrene butadiene or scryl-lutexes must be added.

No industrial work has been done between these two areas now - extremely low concentration and completely dry production.

According to the present invention, however, how to the above problems with the large vnttenmüngdernu and the restrictions on the addition of inhibitors again sweet and produced a process for producing shaped products based on water suspensions sv fibers, which process is characterized by adds one or more hydroholloids to the suspension before molding.

The fibers which according to the invention can be suitably used are fibers of cellulose, slipuussu or spinach, synthetic fiber, e.g. fiber of polyester, yolysmide or acrylic as well as minor fiber of e.g. Asbestos. 7805693-4 According to the invention, it is convenient to susom hydrocolloid use starch, starch derivatives, polyvinyl alcohol, cellulose derivatives, fruit glues such as gun: gun and johunuesbröd- kernel flour, slginate, synthetic hydrocolloids such as polyacrylamide or meal meal such as wheat, oats, rye, barley, etc. or root plants such as potatoes or tapioca.

The invention is particularly advantageous for those concentrations of fibers and colloids shown in the curves in the figures 4 - 12 below.

The bydrocolloid can be added to the fiber suspension dry or after dissolving in water.

According to the invention, the molding can take place at such a high temperature that the shaped product expands due to release steam or other gas formation. The molding can also have a rune under high pressure.

According to the invention, it is suitable to carry out the shaping by extrusion and injection molding with machines similar in the plastics industry or by filling, pressing and drawing with machines similar to those in the metal industry.

The íibors suspension you receive after the addition of the hydrocolloid consists of a homogeneous plastic and cohesive paste of fiber, water and colloid. This pasta has completely properties other than the fiber suspensions as normal used in the production of fiber products. About one traditional iibers suspension is subjected to extrusion, injection molding, beading or pressing takes place instead a dewatering after which the extrusion and injection molding nozzles are clogged with unwrought fiber. Pulling off traditional fiber suspension is completely impossible as the the ion has no cohesive strength. 7805693-4 Sisol can be seen from the subsequent experiments down in water quantities at the formation of approximately 2 times the dry matter content, which is a significant improvement compared to 200 times in traditional production of paper and cardboard.

Fortunately, the colloid is both process aid in shaping by binds the water and prevents the fibers from (looks as well as functional aid for the final product through one it Incorporates as a binder and thus provides mechanical strength.

For the binding of the water, more hydrocolloid is needed than what son is usually used as a binder in traditional methods. As can be seen from the experiments, a suitable colloidal nïngd approximately 1/3 sv the amount of fiber. The invention has thereby eliminated the restrictions on binder appointment as nïmndel initially.

The invention will be described in more detail below with reference to the attached figures 1 - 12. The figures relieves specimens, as the invention can of course be practiced in many different mechanical equipment as well as combination the possibilities: ellen fibers and colloids are innumerable.

Pig. 1 shows how fiber 1 can be dissolved in water 2 in one pulper 3 equipped with a stirrer 4. The vigorous stirring separates the individual fibers from each other in one for and the suspension is then transferred to the filter 6 for concentration, also pi per se known manner. Separated water 7 from the filter 6 can be returned to the pulper. On the road from the pulper to the filter, a purification may optionally be performed of the mass 5 for removal of contaminants. After straining over the filter 6, the mass can optionally be further concentrated by pressing 8 and then hydrocolloid 9 is added, which incorporate by curing 10 with paste ready for molding obtained. The forming can be performed as an extrusion directly out from the kneading partner or in special equipment. 7805693-4 Fig. 2 shows shaping with extruder 1. The extruder is set by heating or cooling desired temperature. High temperature gives, as will be seen later, the possibility of higher concentrations. To further facilitate drying can a pre-dryer is performed e.g. with an infrared dryer 2 before it the extruderude profile is applied with steam heated mold boxes.

Cup, above the rotating Iormlddornn, to be taken the heat in the released steam is not plotted. When the Iorm boxes before each other 3, the web is divided into desired straw games, and when the drying is complete, the manufactured product is released more. with compressed air 4. Before new pasta. added to. íormlådorne these can be cleaned and otherwise sweetened. Fig. 2 wines extrusion of profile, but one can of course also use a wide flat extruder die to produce flat sheets, which are dried and reworked on the same sweet as cardboard.

Fig. 3 shows intermittent extrusion into molds, or as it is called in the plastics industry - "injection molding".

The upper part of the mold tool is permanently mounted to extruder nozzle 1. The lower part is moved up to the nozzle for applying pesto and is then withdrawn with same device 2. After this formniug the substances are dried step by step through a drying plant. Coupon above the drying plant, to produce liberated steam, is not registered. After drying, loosen at 3 the finished the objects.

By extruding pasta at temperatures above 100 ° C Atmospheric pressure expands water vapor to a porous product obtained. Packaging with hard surface and soft shock absorbers The inner side can then be produced by the fabric is first held above the saturation pressure..Nir the pressure so reduced, the part of the mold that forms the outer side below saturation temperature and the other side above.

Sandwich constructions with expanded core and compact surfaces can be produced by cooling both surfaces at 7805693-4 the extrusion while the core maintains its high temperature.

The principles of foam plastic manufacturing can be transferred.

Articles made according to the present invention can naturally combined with other materials, e.g. so that a box made according to the invention is sprinkled with decorative paper or lined with waterproof material.

As mentioned, the water bond requires a larger colloidal additive than what is normally used as strength enhancement means for the production of paper and board. This big amount of binder may appear to be a disadvantage of the present invention, since one generally reasons so that all "Agents" and additives make the process more expensive.

In the present case, however, this is not the case, which most easily explained by the fact that the most common colloid - starch - costs about the same as cellulose. If therefore, replace cellulose with a mixture of starch and cheaper, weaker fiber, so the cost of raw materials per tonne lower, and the strength compensates for the lower strength.

The only type of paper or cardboard that in stiffness and hardness can be compared with products made according to the present invention is so-called "laminated cardboard", where mouth first in a production step produces paper as in a subsequent production step is glued together in several layers.

Plan test sheets were manufactured according to the invention in range 400 - 1200 grams per 12 and was compared by stiffness measurements with marketed, laminated cardboard. It turned out then that only the most expensive qualities of laminated carton could have the same stiffness - at the same basis weight - which the present invention provided with the cheapest the raw materials. Such rigid laminated board must be made of krsftmoasahaltigs paper types. which costs about l500 kronor per tonne, while according to the invention one receives equal rigid cardboard e.g. by extrusion of a pnsta consisting of 23 ß newspaper-filled to SEK 200 per tonne and 8 ß starch (See Fig. 8) to SEK 1,400 per ton or so vaossss-Å to an average raw material cost of SEK 510 per tonne.

Thus, with the present invention, one can reduce the raw food cost node to about 1/3 of the normal with craan-.imm11almnoder.

Due to the high content of binder, it is present invention particularly interesting for the production of products where stiff, hard and woody character raises the end product nose market value, such as packaging in the form of sv boxes and cartons. The invention is also particularly interesting then you want to make hollow objects, as it is difficult traditional methods where one must start from plan sheets.

On the raw material side, the invention is particularly interesting for reuse of old newspapers. This recycled fiber is, due to uv its low strength, less attractive to others recycling methods - and therefore cheap. Son later shall appears, needed for the newspapervfull also less colloid for the mitten binding than for long fibers.

For determining the concentrations and types of fibers and colloids that could be used a whole series of experiments were made.

Boxes similar to cigars were prepared, which after drying resembled more boxes of wood than of cardboard. The boxes - was set by extrusion through a square nozzle with a gap width of 2.5 mm.

For different fiber concentrations, one minimal and one were encountered maximum amount of colloid within which the invention is useful.

The minimum amount was determined, ie the requirement for complete binding of the water and the maximum amount of how thick a paste can be be for it to still be extrudable. 7805693-4 Criterion for maximum amount of hydrocolloid: A viscometer recommended in the plastics industry for measuring the viscosity of thermoplastics after melting was used - a so-called Haake consistometer. This is a thermostatate controlled flow viscometer with piston through which a 2 mm hole has been drilled. The viscosity calculated according to the formula G - t I e K IN viscosity tone in Pascalseknnder = the load in kp time 1 seconds uätstrückan i nn 9- å: n n: u a- n, _g, ¿g n 1 r device coneant for the borehole = 2.5 As a criterion, 10,000 Pascal seconds were chosen, then this in the plastics industry is considered to be relatively high, however however, hassle-free.

The criterion for the minimum amount of hydrocolloidz Sanna Haake consistometer was used "to establish how much colloid was needed to get a homogeneous thread with no tendency to dewater nt of the nozzle.

Drainage tendency can be seen through free (shiny) water in the surface of the trees.

With these two criteria, the angular curves in Pig. 4 - 12 engraved. The fiber concentration has been deposited on the abscissa and the colloid concentration on the ordinate - both in weight percent of whole pasta. The difference up to 100 f is water. Minimi- the criterion gives the left leg in the angular curves and the maximum criterion the higher, and between the legs the invention is thus practical useful.

Figs. 4 - 6, the fiber raw material is old newspapers and extruders. temperature 20 ° C. The colloids are 7805693-4 _ 10 - koM = cold water soluble oxidized corn starch, Amijel M 5 from CPC P = native potato starch G = guur flour, SuperCol U Powder from General Mills oM = oxidized corn starch, Amisol 05594 from CPC H = native corn starch GMC = cerboxymethylcellulose, Majol PS 6 from Uddeholm PVA = polyvinyl alcohol, Covol 9930 from CPC PAA = pulyucrylumide, GR 999 from W R Grace Fig. 5 shows e.g. that at a fiber concentration possibly l6 '% a minimum of 7 ß corn starch is needed as a colloid to bind the water. As the amount of colloid increases, the paste thickens, to be at 10 ß as thick as the possibility of extrusion without particularly powerful extrusion machines can be doubted.

Native corn starch and ordinary cold water-soluble corn starch gave the same curve M. For potato starch, however, it turned out that ordinary litter-soluble type, gave the criteria with lower additives other than present starch. Only the curve for native starch is engraved.P.

On Pig. 7 - 9, the tiber raw material is still old newspapers, but the extrusion temperature has been raised to 85 ° C.

The colloids are P = nntive potato starch CNC = carboxymethylcellulose, MaJo1 PS 6 from Uddeholm G = guar flour, SnperCol U Powder from General Mills IN ll netive corn starch A = ulginate, Protunal H from Protan & Fagertun oM = oxidized corn starch, Amisol 05594_from CPC PVA = polyvinyl alcohol, Covol 9930 from CPC PAA = polyacrylamide, GR 999 from W R Grace 7805693-4 -lli The tip of the angular curves indicates how high the fiber concentration is only work with, still based on the selected criteria terierna. By comparing the corn starch curves N on Fig. 5 and Pig. 8 shows that the increase in extrusion temperature from 20 to 85 ° C causes an increase in maximum fiber concentration from 20 to 28 ß. The colloid concentration at 85 ° C and maximum Iiber concentration is 6 ß so that the amount of water is $ 66 or about twice as dry.

Extrusions were also performed there at temperatures higher than the 85 00, which is the highest temperature for the diagrams. But on due to evaporation, it was with incidental measuring equipment it is not possible to meet the criterion points for minimal and maximum amount of colloid. At 140 ° C an extrusion was performed en post consisting of 41 ß newspapers as Iiber and 6 $ nntiv potato starch as kelloid, sl to ratio water 3 dry matter content was below 1%. The potato potato the fiber mass was set undissolved and gelatinized in heat immediately before extrusion. The extrusion through 2mm mnnstycke went smoothly. After placing the nozzle opening expanded the paste during administration to a filamentous one nets, son after drying showed a specific weight of 0.2 kg / dna against 1.2 kg / dm3 for normal extrusion at temperatures below 100 ° C.

Pl Pig. 10, the tiber robbery is still old newspapers, but instead of using pure hydrocolloid has been used ordinary wheat flour with a degree of refinement cn. $ 78. The extrusions was performed as usual at 20 and 85 ° C. The curves show i.a. that the maximum fiber concentration is lower for wheat flour than for the starches.

Pi Fig. Ll fiber fibers raw old bags of unbleached kraft- paper, and the colloid is native corn starch. The extrusion rings performed as usual at 20 and 85 ° C. The experiments showed that this fiber - sulphate mnsaa - due to easier washing ability, and also greater tendency to flock, required 7805693-4l - 12 - more colloidal than newspaper mass to meet the minimum the criterion, whereby "left elbow" was lifted higher.

This is obtained by comparing with the curves M on Pig. 5 and 8. A Fig. 12 shows that the invention is also useful for synthetic fibers. The fiber selected was polyamide, Perlon x 400 weiss h'matt dtex 2.2 dte: G mn from Bayer and the hydrocolloid was cold water soluble corn starch.

For this Ibern the curves went at 20 and 85 ° C so surprisingly close to each other that the curve in Fig._l2 applies both temperatures.

The extrusions through the Haake consistometer and others shaping went most comfortably in the middle between the two curve legs and not too close to the tip for maximum dry matter. IN near the minimum criterion and near the tip got the pasta and the alum product a grainy structure - less for grinding masaa One for kraftmassa.

When drawing the criteria knots, the fiber and colloidal the quantities dry-dried. Moisture introduced into the system with fiber or colloid is included as water - during the quarrel in the concentration indications. However, the supply was off in water containing all colloids other than starch and flour eå small that it was discarded in the calculations.

In the following, some experimental data will be provided.

The fiber raw material was dissolved in hot water at 2 ß concentration and crunchy stirring. The resulting suspension was irrigated through a sieve cloth with 3/4 mm mesh width and pressed so between hands to dry contents between 10 and 35 ß.

To obtain reproducible curves, it turned out very important to always use the same temperature - time - process during preparation and storage of pustaer before measurement 7805693-4 .IJ- ev criterion points. Different methods were used for heating water-soluble and carbon-water-soluble hydrocolloids.

Method for hot water soluble colloids: Approx. ¿00 grams of fiber suspension and torri-mixed colloid in such a case but tries to "meet" what is sought criterion, is placed in a closed glass jar in a heating cabinet at 110 ° C for 10 minutes. The temperature of the heating bucket is then heated to 95 ° C at which temperature the sample is obtained stand for 30 minutes, after which the glns jar can be opened and after rapid stirring of the contents, viscosity meets and padding at 85 00. The rest of the sample is given stand another 60 minutes in the closed glae jar - now at room temperature - after which but measure the same two criteria at 20 ° C. If the samples get size longer In 60 minutes at room temperature, worse water is obtained. binding and higher viscosity.

The corn starch curves, oxidized corn starch, potato starch, wheat flour, polyvinyl alcohol, electric yeast, CNC and guer are plotted after meeting in this way, even if the latter three colloids are actually so a method mentioned below is also useful.

Method for carbon soluble colloids: Cold water-soluble colloids give easy clumping upon addition to the fiber suspension. In order to avoid consequent clogging en hole in the consistency meter, the powder must be sprinkled very evenly, gently and in small portions over the fiber suspension sioneus surface, and one must knead very vigorously immediately after the addition of each serving. Also in this method ce was used. 200 grams of suspension for each sample. Measurement of possible viscosity and water content at 20 ° C was performed immediately after the addition of last portion colloid. The rest of the sample got size x vaossäs-4 _14- 90 minutes 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 polyacrylamide. If the method was used for GMC and guar needed es. 1 $ more colloid than with it set up the "hot water soluble method", probably due that the colloids dissolve incompletely without heating. constantly.

Finally, some experience gained from the drying of the pasta samples.

If the drying was carried out in a heating cabinet at 105 ° C, then that 1 mm tocka pasta cakes were allowed to lie and dry on untreated iron surface could difficulties with the subsequent detachment from jïrnytan occur. Experience suggests that the removal occurs most easily when adding a large amount of colloid and at use of the most effective colloids for water binding, or in other words when working in areas close to the the criterion in Fig. 1 - 12.

If the test pieces were instead heated on a hot plate, the problem was 'with the detachment considerably reduced, and in the case of genome-cutting of the dried test sheets could be found to be an enrichment of colloid in the surface against the hotplate. This confirms the recent made claims that a large amount of colloid facilitates losatagningen. The greater amount of colloid in the surface of the sample the sheet from which the worm was added can be explained by the colloid travels with the water towards the heat-emitting iron the plate where the water evaporates, and the hydrocolloid becomes lying still, di it can not wander back with the steam.

If the drying was performed on Teflon coated metal mold, occurred no problems at all with loosening the pre-dried ones the fiber products.

Claims (6)

7805693-4 _ 15 _ Pstentkrav Process for the production of shaped products based on sensory suspensions of fiber, characterized in that but only after a possible watering or suspension during kneading or similar processing of the pulp adds one or more new hydrocolloids in such an amount a remaining water is completely bound, after which the products are formed by extrusion, injection molding, rolling, pressing, drawing, etc. and the custom is dried or hardened in the snnst manner. Process according to Claim 1, characterized in that wood fiber, e.g. cellulose or abrasive fibers, synthetic fibers, e.g. fiber of polyester, yolyamide or acrylic as well as mineral fiber possibly e.g. Asbestos. Process according to Claim 1 or 2, characterized in that the hydrocolloid used is e.g. starch from any plant, starch derivative, polyvinyl alcohol, cellulose derivative such as carboxymethylcellulose and hydroxyethylcellulose, plant glue such as guar flour or locust bean gum, alginate or synthetic hydrocoilnides such as e.g. polyserylamide, flour from cereals such as wheat, oats, rye, barley, etc. or from root plants such as potatoes and tapioca. Process according to one of Claims 1 to 3, characterized in that the concentrations of colloid and fiber which can be used are those which appear from the curves in Figures 4 to 12. Processing according to one of Claims 1 to 4, characterized in that the hydrocolloid is added to the fiber suspension dry or after dissolution in water. Process according to one of Claims 1 to 5, characterized in that the molding takes place at such a high temperature that the molded product expands due to free-ground steam or other gas formation. Process according to one of Claims 1 to 6, characterized in that the molding takes place under high pressure and high temperature. THEREFORE PUBLICATIONS: Sweden putentnnsöknn 7608245-2 §D21J 1/16), 210 080 (D21J 1/16), 335 492 gC04B 43/02 Great Britain Germany 1,058,828 (D21J 1/16)