DE3302841A1 - Flame-retardant sheet or the like and manufacturing process therefor - Google Patents

Abstract

In a process for manufacturing flame-retardant construction material sheets, textiles, films or like materials which at least partly contain swellable fibres, said fibres are prepared, swollen with waterglass solution, and the waterglass in the fibres or the sheets, films etc. is colloidally precipitated out of the waterglass solution with the aid of a precipitation catalyst. This consists preferably of a diammonium hydrogen phosphate solution. The precipitation reaction takes place reliably below a pH of 11, preferably a pH around 10. At the same time, a concentration of the waterglass solution approximately between minimum 7 and maximum 70 per cent by weight is expedient for the reaction, preferably a concentration between 7 and 25 per cent by weight waterglass in the waterglass solution. In this manner, environmentally friendly, flame retardant construction material sheets, textile webs, films and the like can be provided which are both thermally and acoustically insulating and flame retardant and especially also avoid the disadvantages of asbestos sheets or similar asbestos products.

Description

Flame retardant plate or the like and manufacturing process therefor Description The invention relates to a method for producing flame retardant Building material panels, textiles, foils or

Like. Materials that contain swellable fibers.

As a fire protection material are z. B. Asbestos and rock wool layers, also known in the form of plates. Glass wool layers are also known. Both asbestos as well as stone and glass wool are incombustible, but have considerable material properties Disadvantage. Asbestos can, for example, become too cause considerable damage to health (asbestosis and asbestos cancer). Made of fiberglass one cannot form solid plates, but these fibers only as fleece for Use isolate. The same applies to rock wool. The aforementioned mineral fibers also do not offer any special heat, cold or noise protection, as is the case, for example is the case with a wooden panel.

We also already know wood fiber insulation boards, which on the one hand have the Avoid the aforementioned disadvantages of asbestos, rock wool and glass wool layers. Construction elements made on a wood basis can also be easily made into foils or panels Manufacture of very different thickness, but such are based on wood The components produced are easily flammable; they do not offer adequate protection against fire. u Cardboard or wood fiber insulation boards have already been proposed to make it more difficult to ignite by z. B. water-insoluble or in Attempts to fix water-soluble fillers to the wood fibers. These attempts however, did not lead to the desired results.

There is therefore the task of creating a method with the help its building material panels made on the basis of wood and / or textile fibers, Cardboard boxes, foils, textile fibers or the like "flame-retardant", possibly even "non-combustible" can be made. In addition, there is the task of such building material or insulation panels, Cardboard boxes, textile fibers or textile fabrics, chipboard or the like. To create.

The solution according to the invention for the production process consists in this essentially that in a method of the type mentioned in Claim 1 listed process steps are carried out. One obtains thereby, as will be explained in more detail below, for example insulation panels or tent sheets, in and / or around the fibers of which there is water glass and another substance that exert a flame protection or a flame retardant effect.

The invention also relates to flame-retardant panels, foils, etc., z. B. Building material panels and textile sheets. These are characterized according to the invention in that the plates or the like contain a proportion of swellable fibers, which are swollen with water glass solution and from which this water glass solution is colloidal has failed.

Additional developments of the invention are given below Description and in the features of further subclaims explained in more detail. The invention with its essential details is based on the following of exemplary embodiments and described in more detail with the help of the drawing. It show in a highly schematic way: Fig. 1 A flow chart for the production of paper, Cardboard or the like in a known manner, FIG. 2 shows a partial flow diagram of the inventive method Manufacturing method and in each case greatly enlarged. FIG. 3 shows a cross section of a fiber swollen with water glass solution and FIG. 4 shows a cross section through a Fiber according to FIG. 3 after precipitation.

A known manufacturing method will be described below with reference to FIG written on cardboard or paper, which is also used to manufacture insulating panels, Pressboard, etc. can serve. The individual work steps are through a with box marked I, II etc. are shown and included a catchphrase to characterize the respective work step, without the The work step referred to is related to the activity mentioned in the key words needs to restrict.

u-nah! 3 Position I begins the familiar flavor sequence for production of cardboard or paper with the "starting products". As fiber raw material z. B. used wood and wood waste. As far as these starting materials in the invention 2, steps 1 and 4, it must be swellable Fiber raw material, d. H. are natural fibers. As a starting product z. 3. Natural, swellable textile fibers also question. The procedure, one already To make woven textile web flame retardant, however, is in a separate embodiment treated.

In the work step according to II, the raw fiber material is shredded, z. B. with a rotor rake. In a further step marked III Then the pulping of the raw fiber material already shredded at II takes place. Corresponding The desired end product can also be "defibrated" in step III "cleaning" and "refining" are added.

In the previously known method for producing cardboard, paper or the like, the next step is "sources" in accordance with item IV of the pulp in an aqueous liquor.

this usually takes place at a temperature between 50 and 800 ° C instead of.

The swollen product then arrives in accordance with the previously known method in the "Dutch". The next work step, denoted by V in FIG. 1, takes place there the "grinding" of the fibers takes place.

Fillers are also usually added in this step, z. B. chalk, kaolin, paint, glue, bitumen and the like.

After a certain mixing time, the additives become part of a The precipitation process is fixed on the fibers with the help of aluminum sulfate (alum).

After the aforementioned fixing is usually carried out as the next step Storage in accordance with Item VI in storage chutes. The content of this Storage chests brought to a "headbox" according to the next step VII. In a corresponding machine, the "white water" can run off there and form the "sheet" is located above a sieve belonging to the corresponding machine. Included In the manufacturing process described above, both a "sheet" and a thin sheet can be used Sheet of paper as well as a z. B. 50 mm thick plate. The "5iebwasserpartie" are then usually nachgescnaltet vacuum boxes, press rolls, etc., which the further dewatering and solidification of the fibers and thus of the leaf or effect of the plate. As a rule, these also go through a drying tunnel. At the end of the above-described workflow, the finished product is then available in accordance with Item VIII in the form of sheets of paper, cardboard, plates or the like. These products are like known, easily flammable and offer no protection against fire.

The invention now begins at the following point: The work steps according to the dashed boxes according to items I to III are in an execution of the method according to the invention as the (known per se) processing of the fibers viewed and these processed fibers are according to the position symbol A of the work flow from FIG. 1 is transferred to the work flow of FIG. Included In the process according to the invention, those explained under IV and V, shown in FIG. 1 operations indicated in the dash-dotted boxes.

The processed fibers are processed in step 1) according to FIG. 2 swelled in a water glass solution. Then comes the next step accordingly Pos. 2) the "grinding" of the pulp swollen by the water glass. GemGz3 the next In step 3, the excess waterglass solution is removed (pumped off). This is followed by a very important one besides swelling in water glass solution more inventive Step, namely according to step 4) the colloidal precipitation of the in the Fibrous water glass from the water glass solution with the help of a precipitation catalyst. The precipitation catalyst in question should preferably not only be additionally flame-retardant Have properties, but also specifically to the one used in each case Alkali-silicate-type (commercial qualities) and their solution concentration be coordinated. As corresponding tests have shown, the use is cautious a diammonium hydrogen phosphate very well suited to the condensation process of To initiate the water glass correctly and to dominate the process.

Such a condensation process, moreover, lies in the knowledge based on the fact that the tendency to form Si-0-Si-0-Si chains is generally very strong is, d. H. that all alkali silicates are usually "unstable" and the property have to develop into higher molecular weight, ultimately colloidal aggregates with condensation to merge. In the case of water glass, this kind of condensation hardly occurs below pH 11 to such an extent that the resulting network and leaf structures first as "silica gel", then with further release of water as "Silica gel" and finally precipitate as water-insoluble silicon dioxide (sir2). For this reason it is necessary for the fiber to be as flame retardant as possible It is essential that the colloidal precipitation of the water glass from the Alkali silicate solution only takes place after the fiber is largely soaked and the water glass is finely and evenly distributed everywhere. This can be done with favorable conditions, as z. a. Softwoods offer a ratio of 1: 9 (fiber : Solution) be.

Another essential requirement for the introduction and implementation of the condensation or precipitation process according to the invention is the careful one Checking and controlling the pH value. In particular, the addition of the catalyst must be undertaken so carefully that as a result the relative height alkaline initial pH value of the water glass solution on the one hand not too fast or drops suddenly into the acidic range (with the risk of local acid residue concentrations), on the other hand, however, the precipitation process does not take place too slowly, because it does so in turn, the condensation process would be severely disturbed (risk of insufficient Dehydration).

The water glass primarily effects flame protection in the fibers, the phosphate, on the other hand, hinders the afterglow more. In the combination of water glass and diammonium phosphate Both substances prevent the fibers from catching fire and afterglowing, which results in "asbestos-like" behavior in those produced in this way Plates od. The like. Achieved, although the raw material made of natural fibers with which has these own advantages. Accordingly, according to the The above-described method produced plates, foils or the like. Materials on the one hand very favorable cold insulation, heat insulation and sound insulation properties similar to wood fiber insulation boards, at the same time, however, these panels also provide effective protection against fire, as they are "flame retardant". Accordingly, have the according to the invention Process produced plates, foils or the like. In each case advantageous material properties of different materials, without the respective disadvantages of these previously known different materials have to be accepted.

It has surprisingly been found that the bringing together of the two solutions, namely water glass and diammonium hydrogen phosphate solution, automatically a natural one Precipitation reaction within the soaked fibers triggers if one takes appropriate conditions into account. When using the aforementioned Reaction chemicals has a concentration of water glass solution between 7 and 70 percent by weight have been found to be expedient, preferably one concentration between 7 and 25 percent by weight of water glass in the water glass solution. Furthermore is when using the aforementioned solutions advantageous that the precipitation reaction at the waterglass solution is carried out at a pH that depends on the concentration of the solution lies approximately between pH = 7 to pH = 11, preferably at a pH value of around 10. Thereby must control the aforementioned pH range at which the precipitation reaction takes place - as known to the chemical expert - not too quickly, but also not driven too slowly. Tests have shown that an approximation time leads to a precipitation reaction of about 2 to 3 minutes.

Accordingly, there is a practical implementation of the method a development thereof is that in the precipitation process, preferably at several different points, pH measuring devices check the resulting pH values and preferably control the measuring equipment of the precipitation process.

In this way one can achieve that the acidification of the waterglass solution also locally evenly, z. B. is achieved within a larger container.

Appropriately after the precipitation of the water glass solution takes place an addition of auxiliaries and / or fillers that are mixed with the fibrous materials. This is usually done and is in a mixing vat or a Dutchman Work step 5) indicated in FIG. 2. In this case, if necessary. In a known manner Precipitation takes place with aluminum sulfate. As according to the workflow diagram As can be seen in FIG. 2, the fiber suspension according to the position symbol B is then selected the workflow according to FIG. 2 at the corresponding point in the previously known Workflow according to FIG. 1 introduced, namely in step VI "Storage". The remaining work steps can then be carried out in the manner initially described in items VI, VII and VIII described manner.

There is an advantageous further development of the method according to the invention nor is that the fibers prepared in steps I to III before they come into contact with the water solution according to step 1) (Fig. 2), be dried beforehand, as in the step shown in dash-dotted lines 0) is indicated according to FIG. Usually the processing of the fibers brings in the work steps I to III a possibly considerable wetting of the fibers with it. By drying, e.g. B. in a cyclone dryer, it is achieved that the drier Fiber better resp.

be able to absorb more water glass solution in step 1).

It has also been found that the swelling of the pulp in the water glass solution according to step 1) is particularly favorable at one temperature from about 10 to 200 ° C takes place. Swelling in a water glass solution that is as cold as possible is advantageous because the swelling solution is anyway due to the subsequent "grinding" warmed up. An advantageous further training that improves the economy of the process consists in the fact that the mixture of fibers and water glass solution according to the water glass solution pumped off in step 3) is fed back into the manufacturing process will. Pumping off the excess waterglass solution (step 3)) also has the task of preventing the corresponding container from falling out Excess gailert-like "silica gel" forms, whereby the entire further Production process could be disrupted. The aforementioned drying of the fibers before The swelling with water glass can possibly. After washing, cleaning and / or a Special treatment (e.g. removal of the lignin) of the fiber is carried out.

A slightly modified embodiment is that with the method described above thin sheets, paper or the like. In the method described above Way to be made. It can be used as a starting material instead of wood fibers also swellable textile fibers, d. H. i. d. R.

natural textile fibers to serve. Possibly. you can too work with a mixture of appropriate swellable wood and textile fibers.

As natural, swellable fibers, both in the panel as well as dried plants, straw, reeds, cotton in the production of film and the like in question.

Another, somewhat modified embodiment consists in the Application of the process in the textile sector. Instead of the previously known work steps I to III or the process step a (preparation of the fibers) can manufacture a textile web, e.g. B. step a tarpaulin. It essentially consists from swellable, d. H. usually natural textile fibers. Such a tarpaulin is then impregnated with water glass solution according to process steps b and then the precipitation takes place in the manner already described according to method step c of the water glass.

If necessary, the excess can also be used in this exemplary embodiment Water glass solution can be withdrawn before precipitation, for example when soaking the tarpaulin took place inside a container. Possibly. can also be a Such tarpaulin or the like. Textile web before swelling with water glass solution if necessary still be dried, as in connection with the process step 0) according to FIG. 1 has already been described.

Regardless of the raw materials and the desired end product (Plates, sheets, foils, textiles, etc.) there is an advantageous further development the method is that after the precipitation of the water glass the fibers, for. B. by means of a heat treatment, additional water is removed. Namely, this results in more desirable Way to get more and more quickly from the original silica or silica gel pure silicon dioxide (SiO2) is produced.

The aforementioned withdrawal of water can be done by adding heat in the course the already described further processing according to the known work steps VI to VIII take place.

Water glass (solution) comes on the basis of potassium silicates as well as sodium silicates.

Two very essential steps of the invention are illustrated with the aid of the figures 3 and 4 will be explained. Fig. 3 shows, greatly enlarged, a fiber F, which with The water solution is aurgewellt, whereby the water glass solution through the inclined Hatching lines is indicated. In Fig. 4 the same fiber; 'is shown after she has been exposed to a treatment with diammonium hydrogen phosphate solution and the precipitation process has taken place. In the fiber F 'oof are found accordingly that is, in addition to the silicic acid salts precipitated from the water glass solution (dash-dotted Hatching) also the salts of phosphoric acid, which are indicated by crosses are.

It should also be mentioned that the fibers F, as tests have shown, during the swelling process can soak with water glass solution that it up to a ratio of 1: 9 of fiber weight to waterglass solution weight can.

In addition to finding the appropriate swelling solution, namely the water glass solution, and a suitable precipitation catalyst, in particular the diammonium hydrogen phosphate solution as an important aspect for the invention also that when they are brought together of these two solutions under the corresponding, detailed conditions natural precipitation reaction takes place.

Fig. 4 shows at the same time a greatly enlarged, schematized Partial cross-section of the product resulting from the aforementioned process. This not only has the advantages already mentioned at the beginning, according to which on the one hand it is good heat, cold and sound insulating, but at the same time also flame retardant. In addition, the corresponding process products (sheets, foils, textiles etc.) non-toxic and particularly environmentally friendly. This also applies in particular with regard to the composition and dosage of the chemicals involved in the filling process (tea glass and phosphates). (In the examples above, one ilasserglas on the Based on sodium silicate.) The process according to the invention can also be used for starting materials, which contain other components in addition to swellable fibers, such as z. B. is the case in the production of chipboard. You just have to pay attention that it contains a sufficiently high proportion of swellable fibers. Possibly. textiles can not only be used in the finished fabric, but also as yarns accordingly be treated.

Auxiliary and / or additives to be added after the waterglass solution has precipitated out Fillers are chalk, glue, kaolin, paint, waxes, bitumen, etc. As already mentioned, such auxiliaries or fillers can be precipitated with aluminum sulfate (alum). They can also be fixed to the fiber using other commercially available fixing materials.

So that the precipitation process of the water glass, even with industrial ones Production, e.g. B. in larger containers, is not missed, are on several, pH measuring devices are attached to different places, which control the pH values.

Appropriately, these measuring devices are used, for. B. to control the precipitation process via electrical or electronic links. For example, the local concentration of acid residues is measured. Accordingly the rate of acidification of the waterglass solution is controlled.

At another point in the process sequence, namely in step 5 (Fig. 2) a similar control and control can take place, namely the phase the glue precipitation.

A major advantage of the method according to the invention or the Plates, foils, etc. produced therewith consist of the following: One achieves that a flame-retardant material or a combination of flame-retardant materials is incorporated into the fiber and is fixed in it. Through later machining processes, atich in the manufacturing process, these flame-retardant substances can then no longer be lost.

All of the features described above and / or listed in the claims can, individually or in any combination with one another, essential to the invention be.

Claims (18)

Claims; Process for the production of flame retardant Building material panels, textiles, foils or the like. Materials that contain swellable fibers contain the following procedural steps: a) The fibers are processed; b) the fibers are swollen with water glass solution and excess waterglass solution is removed; c) that in or on the fibers, Plates, foils or the like. The water glass located in it becomes colloidal with the water glass solution With the help of a precipitation catalyst precipitated. 2. The method according to claim 1, characterized in that an on the type of water glass used and its solution concentration, the coordinated precipitating catalyst Has a pH value between 7 and 11 and expediently has flame-retardant properties Has. 3. The method according to claim 1 or 2, characterized in that the colloidal precipitation of the water glass from the water glass solution with a diammonium hydrogen phosphate solution he follows. 4. The method according to any one of claims 1 to 3, characterized in that that the concentration of the water glass solution between 7 and 70 percent by weight is, preferably between 7 and 25 percent by weight of water glass in the water glass solution. 5. The method according to any one of claims 1 to 4, characterized in that that the precipitation reaction in the water glass solution takes place at a pH value of depending on the concentration of the solution, is approximately between pH = 7 and pH = 11, preferably at a pH around 10. 6. The method according to any one of claims 1 to 5, characterized in that that the swelling of the pulp in the waterglass solution at a temperature of about 10 to 200 ° C takes place. 7. The method according to claim 1 to 6, characterized in that the Lowering the pH of the water glass solution in order to carry out the colloidal precipitation It is done so carefully that it results in the high alkaline pH starting value of the Water glass solution does not suddenly drop into the acidic range, but the precipitation of the water glass in the fibers is in the pH range around 10, preferably that the precipitation reaction takes place with an approximation time of about 2 to 3 minutes. 8. The method according to any one of claims 1 to 7, characterized in that that the fibers are dried with water glass solution before swelling, if necessary after washing, cleaning and / or special treatment (e.g. removing the lignin). 9. The method according to claim 1 to 8, characterized in that the Mixture of fibers and water glass solution during and / or after swelling is ground. 10. The method according to any one of claims 1 to 9, characterized in, that after swelling the fibers with water glass solution, preferably in a container Excess waterglass solution contained therein is drawn off will. 11. The method according to claim 10, characterized in that the withdrawn excess waterglass solution is reused according to the recycling principle. 12. The method according to any one of claims 1 to 11, characterized in that that after the precipitation of the waterglass solution, auxiliaries and / or fillers are added and mixed with the fibrous materials, possibly with a precipitation with aluminum sulfate takes place or other fixatives are used. 13. The method according to any one of claims 1 to 12, characterized in that that in the course of further treatment after the precipitation the fibers, plates, textile webs, Foils or the like. any water absorbed in the silica gel or silica gel is withdrawn, preferably by pressure, heat, mechanical or other treatment. 14. The method according to any one of claims 1 to 13, characterized in, that if the water glass fails, preferably in several different places, pH measuring devices control the pH values and expediently the precipitation process steer. 15. The method according to any one of claims 1 to 14 for the production of flame-retardant building material panels, foils or the like. Material, characterized in that for the preparation of swellable Fibers from starting products such as residual wood from the sawmill or similar starting products it is assumed, expediently in a first processing stage, the comminution of the wood or the like. swellable base materials takes place, preferably in a second Phase the defibrillation (defibrillation) takes place and expediently adapts to it followed by cleaning and refining of the fiber raw material. 16. The method according to any one of claims 1 to 14 for the production of flame retardant textiles, e.g. B. tarpaulin or yarn, characterized in that that as preparation of the swellable fibers, the production of yarns or a corresponding textile web is made, which is at least partially made of natural, swellable Fibers. 17. Flame retardant plate or film, e.g. B. Building material panel, textile web Od. Like., characterized in that they have at least a significant proportion of Contains swellable fibers which are swollen with water glass solution and from which this water glass solution is colloidal. 18. Plate or the like. According to claim 17, characterized in that in and / or on their fibers swollen with water glass, silicon dioxide and prophoral salts are located. - Description -