DE3003371A1 - Scarcely flammable fibrous material prodn. - e.g. paper, cardboard, paperboard, fibreboard, with addn. of boron mineral and acidification - Google Patents

Abstract

In the prodn. of fibrous material, e.g. paper, cardboard, paperboard and fibreboard, from a (vegetable) fibre mat, 3 stages are used (conversion of the wood and other raw materials to half stuff, conversion of this to whole stuff and prodn. of the final fibre mat on endless or round wire machines). Conversion to the whole stuff includes milling the fibres to pulp and addn. of finishing agents. The novel feature is that B minerals (I), e.g. boracite, borax, colemanite, kernite-pandermite, rasorite or ulexite, in finely ground form, are mixed with the pulp, then mineral acid, esp. H2SO4 (96%) or phosphoric acid is added, pref. in the stoichiometric amt. needed for boric acid formation from (I). The pulp is then ripened for ca. an hour before conversion to the end prod. Very good fire retardancy is imparted with little increase cost of the end prod. Ca sulphate is formed in the conversion of (I), which imparts very high strength.

Description

Fiber material

The invention relates to a method for producing a fiber material such as paper, cardboard, paperboard and fiberboard, formed from a sheet or plate-shaped Tangled fibers, preferably made using vegetable fibers, there are three phases in its production - the processing of wood and other raw materials to pulp, the processing of the pulp to the raw material and the production of the closed fleece on Fourdrinier or cylinder mold machines - to distinguish The preparation of the pulp is the grinding of the fibers into a pulp and the addition of finishing agents.

The constantly increasing demands on the fire protection of materials of all kinds make it necessary, including this one Fiber materials before To protect fire or to equip it in such a way that it does not start or continue and support a fire. The manufacture of these fiber materials succeeds economically only in the wet process, for example for the production of one kilogram of paper up to 300 liters of water, for the production from 1 kg of fibreboard up to 100 liters of water are required. The production so happens in very thin aqueous suspensions what the introduction of Fire retardants, such as boric acid, for example not or practically not in Are soluble in water. The object of the invention is therefore to provide such to introduce water-insoluble fire retardants into the fiber materials without the proven and economically feasible wet process in their manufacture must be given up.

In the German patent application P 28 31 616.7 is a method for the production of a non-combustible one made from mineral materials Material specified in which using residual sewage sludge and / or moist wood cutting chips a solid body is produced in that this Boron minerals are added to the basic materials, these boron minerals with concentrated sulfuric acid are added and the resulting mixture is then glued with a plastic resin and is hot-pressed. This material that can be achieved in this way has similar material properties like chipboard, however, is due to the proportion of boric acid it contains as well at least partially glass- or ceramic-forming minerals, non-flammable. the The relationship between this well-known material and chipboard is also reflected in the species its manufacture, except for the preparation of the fire retardants with the manufacture from Chipboard is identical. The starting materials are therefore practically dry, or have a minimum of humidity up to a maximum of 25%.

In contrast, the fiber materials covered by the invention produced in the wet process on paper machines - Fourdrinier or cylinder mold machines, the aqueous starting suspension having a solids content of only 0.5 to a maximum Should have 2%. So in the case of the known material production it would still be the dry application of powdery, water-insoluble fire protection materials possible, so this separates in the production of the mentioned fiber materials, which are paper-like or are made from cardboard, cardboard or fibreboard. Nevertheless, the invention this proven process of converting boron minerals into boric acid can be used make, since the application of this procedure not only promises good fire protection to achieve, but because it is also very economical.

Another consideration when using this known method is that it should be possible with the combination of the known wet process for the production of paper, cardboard, cardboard and fibreboard using the known process for dry production of fire-protected materials, reinforced plasterboard produce which should have relatively good strength properties. Such plasterboards are urgently needed for dry interior work and plastering Walls are required because they not only have good properties that improve the indoor climate have, but also easy to assemble and, when using the invention Process should also be economically producible. Here, too, would be a matter of course Fire protection is very important, as this protection is particularly important for the interior lining demanded by rooms must become.

According to the invention it is possible to use the fiber material described in the introduction to produce in a fire-protected design by adding boron minerals to the pulp such as boracite, borax, colemanite, kernite, pandermite, rasorite or ulexite is added in finely ground form that after equal division of this mineral or these minerals to the mixture of mineral acid, in particular sulfuric acid (968-) or phosphoric acid, preferably in that for the formation of boric acid from the boron minerals necessary stoichiometric amount, is added and that the so pretreated After a maturing time of about one hour, the fiber pulp becomes the desired fiber material is further processed.

Without leaving the tried and tested wet process, the Base materials for the production of paper, cardboard, cardboard and fiberboard minerals added, which have a fire-retardant effect on their own, but also boric acid, which is known to have very good fire protection properties.

These fire protection materials interfere with the known manufacturing process these materials are not and are also extremely inexpensive, so that the end products are only marginally more expensive as a result. The extraordinary progress in this is, however, that the end materials are not only fire-proof, but due to the fact that calcium sulphate (gypsum) is formed during the conversion of the boron minerals, a very high strength of the materials is achieved. This can be explained by this that the Colciumsulfat supports the bonding of the individual fibers to each other or the tangled fiber is extremely solidified.

However, not only fiber materials can be used in this way how paper, cardboard, paperboard and fibreboard are made, but1 like this has already been mentioned, also reinforced plasterboard, whereby that should be formed Calcium sulfate for the characteristics of this forming fiber material as Gypsum board may not be sufficient, it may also be made more suitable for the pulp Plaster of paris can be attached. This creates a completely new fiber material, the is of extraordinary importance, especially for the interior design of rooms, since it significantly improved strength properties compared to the known plasterboard having.

Instead of introducing the mineral acid in a stoichiometric ratio, it can also be added in such an amount that the mixture immediately after Adding the mineral acid, a pH value between 1.5 and 3.0, preferably 2.0, is achieved. A tendency towards neutralization can be seen when carrying out the process by extending the ripening time after adding the mineral acid.

The addition of the boron minerals is expediently afterwards to the preparation of the stock, i.e. either in the preparation machines - for example Dutch or Refiner - or in the laid paper.

Should a weighting of the starting material be necessary or desired so it is also possible to put the pulp at this stage before further processing add other coarse to fine-grained minerals.

It has proven very useful for the production water to circulate is, as this results in the chemicals dissolved in this production water, in particular the proportion of boric acid dissolved in the water is added back to the production process will. This production water can certainly also be transferred to the fiber fleece on the wire section are sprayed on, with water-soluble fire retardants also being sprayed on can. It is also possible to manufacture two- or multi-layer panels, with due to two-material or multi-head casserole fiber pulp with a relatively higher boron mineral / mineral acid content can be poured onto a previous or forming fleece.

Overall, this results in a fiber material on the fibers of which boric acid particles attached and the spaces between the individual fibers at least partially are filled with plaster, i.e. fiber materials that are more depending on the mineral content fibreboard-shaped or more plasterboard-shaped.

The process according to the invention will be explained in more detail using four examples are: Example 1 For the production of a flame-retardant paper for packaging are registered in the Dutch of the stock preparation for approx. 1000 kg of end product: 321 kg absolutely dry waste paper (newsprint) 321 kg absolutely dry soda cellulose and, after sufficient fiber digestion, 240 kg colemanite with 44% boron content, finely ground.

Fresh water is used first for the pulp and later that from the Production of such paper originating wastewater of the round or fourdrinier machine related.

The fiber / colemanite mixture is now made by slowly adding 117 kg of a 96% sulfuric acid acidified to a pH of 2.0 to 2.5. That Mixture should then ripen for at least an hour and is then as usual further processed.

Until this processing, the pH value has been reduced to approx.

4.5 increased. The end product is a solid, non-flammable one Paper.

Example 2 For the production of a flame retardant cardboard, for example for the interior trim of automobiles, are in the Dutch of the stock preparation Entered for 1000 kg of end product: 300 kg of dry soda kraft paper 200 kg atro waste paper (rolled files) 100 kg Ia soda power.

For the production of the pulp, fresh water and, After the start of production, the return water from the suction section of the Fourdrinier machine related.

240 kg of colemanite (approx. 45% boron content) become homogeneous in the pulp mixed in. As soon as the fiber / colemanite mixture reaches the desired uniform distribution has 117 kg of concentrated sulfuric acid (96%) slowly in the circulating pulp added and mixed until the mixture is homogeneous and has a pH value from 2.0 to 2.5. The material can mature in the machine chest; the pH has then risen to around 4.5 to 4.8. The pulp is processed as usual. The result is a strong cardboard box that is no longer flammable.

Example 3 For the production of approx. 1000 kg of a flame retardant Wood fiber insulation board is in the Dutchman of the stock preparation 643 kg defibrator material or Wood pulp or a mixture of the two substances introduced. This mixture is brought to the desired degree of grinding by grinding and then 240 kg of colemanite (approx. 45% boron content) mixed in homogeneously and then slowly 117 kg of concentrated sulfuric acid (96%) mixed in. The pH of the mixture should be range from 2.0 to 2.5. Then the mixture should be in the vat for about an hour mature and then sent for further processing. The pH after ripening is anc3estieyen to about 4.5 to 4.8. A wood fiber insulation board produced in this way is not only fire-protected, but also has excellent strength values on.

Example 4 For the production of a fiber-reinforced plasterboard in the Dutch of the stock preparation 225 kg of wood pulp or defibrator material or a mixture of both entered and first with fresh water, later with production water, brought in a fiber suspension with 5% solids content. Then 480 kg of colemanite (approx. 45t boron content) are added and mixed until until a homogeneous mixture is obtained. Then 235 kg of concentrated sulfuric acid are added (96%) slowly mixed in, whereby the initial pH value of the mixture does not fall below 2.0 however, it should not be more than 2.8. This mixture matures in the machine chest at least one hour, the pH increasing to 4.5 to 4.8. The fiber mixture is then further processed like a fiber insulation board, but with the end product is to be addressed as reinforced plasterboard.

It is interesting here that the boric acid content of the plasterboard is Circulating production water is about 26% by weight in the end product, the The product is therefore non-flammable in the sense of DIN 4102, class A2, in order to go even further when carrying out this procedure the Character of a plasterboard To obtain it is possible in addition to the matured pulp expediently add plaster mixed with production water.

The end result is definitely a reinforced plasterboard that isn't is only fire-protected or non-combustible, but also has remarkable strength properties having.

Claims (10)

PATENT CLAIMS ====== ~ ===== e ============= Method of manufacturing a fiber material such as paper, cardboard, paperboard and fiberboard, formed from one sheet-shaped or plate-shaped fiber tangle, preferably produced using of vegetable fibers, the production of which has three stages - the processing of wood and other raw materials into pulp, the processing of pulp into raw material and the production of the closed web on Fourdrinier or cylinder mold machines - are to be differentiated, whereby the preparation to the pulp is the grinding of the fibers to a pulp and the addition of finishing substances, characterized in that that the pulp boron minerals such as Boracite, borax, Colemanite, kernite, pandermite, rasorite or ulexite are added in finely ground form that after even distribution of this mineral resp. of these minerals to the mixture of mineral acid, especially sulfuric acid (96%) or phosphoric acid, preferably in the form of boric acid from the boron minerals necessary stoichiometric amount is added and that the so pretreated After a maturing time of about one hour, the fiber pulp becomes the desired fiber material is further processed. 2. The method according to claim 1, characterized in that the admixture the boron minerals takes place following processing into the raw material 3. Procedure according to one of claims 1 or 2, characterized in that mineral acid in such Amount is added that the mixture has a pH between 1.5 and 3.0 preferably 2.0 achieved. 4. The method according to one or more of the preceding claims, characterized in that the pulp before further processing further coarse until finely ground minerals are added. 5. The method according to one or more of the preceding claims, through this characterized that the pulp before further processing with production water, if necessary with the addition of accelerators or retarders, plaster of paris added will. 6. The method according to one or more of the preceding claims, characterized in that the production water is circulated. 7. The method according to claim 6, characterized in that production water is sprayed onto the fiber fleece on the wire section. 8 The method according to claim 6 or 7, characterized in that the Water-soluble fire retardants are added to the production water. 9. Procedure according to one or more. of the preceding claims, characterized in that by two-material flow (Multiple headbox) pulp with relatively higher. Boron mineral / mineral acid content is poured onto a previous or forming fleece. 10. Fiber material such as paper, cardboard, paperboard, fibreboard and fiber-reinforced Gypsum boards, formed from a sheet or plate-shaped fiber tangle, made preferably under Use of vegetable fibers, characterized in that boric acid particles are attached to the fibers and the spaces between the individual Fibers are at least partially filled with plaster of paris.