DK148717B - PATH OR SHEET-FIBER PRODUCT, ISAER PAPER AND PAPER, AND THE PROCEDURE FOR ITS MANUFACTURING - Google Patents

Description

in 148717

The invention relates to a web or sheet-shaped fiber product, in particular paper and cardboard, which, in addition to organic fibers such as cellulose, and a binder contains from 1 to 95% by weight of inorganic fibers such as mineral wool fibers, as well as conventional additives.

From US Patent Nos. 3,418,203, Nos. 3,150,033, and Nos. 2,705,198, fiber products of this kind are known in which the binder which interconnects the fibers contained in the product consists essentially of salts 10 resulting from a reaction between a water-soluble silicate and a water-soluble acid.

The fiber product of the invention differs from the known products in that the binder is based on water glass and has a content of carbamide and propylene glycol.

With a web or sheet-shaped fiber product according to the invention, a product is obtained which exhibits a fast and good bonding effect during manufacture, which means that as a starting product for the mineral fibers, waste material obtained in the manufacture of various products of mineral wool can be used, and that the driving time in the paper machine can be significantly shortened, thereby achieving an energy saving.

The invention also relates to a process for preparing the fiber product, and this process is characterized by providing an alkaline mixture by adding a glass of water to a suspension of the organic fibers in addition to said carbamide and propylene glycol. amount of 1-30% by weight of the total fiber suspension - and the inorganic fibers, after which the mixture is prepared in a manner known per se after further treatment, e.g. after the addition of glue, dyes, 35 fillers and thickeners, work up to the final product.

In a preferred embodiment of the process, the water glass is added directly to the cellulose fiber suspension and the inorganic fibers are added in the form of a separate fiber suspension.

The invention is explained in more detail below by means of some examples.

EXAMPLE 1 In a pulper, glass fibers and 10 water are mixed for 5 minutes to obtain a suspension or a slurry. The intermixed amount of fiberglass includes 10% by weight. In comparison, a conventional cellulosic fiber slurry generally contains 3-3.5% by weight of cellulose, which thus gives a relatively high water content when introduced into a wire for dewatering. A pulp containing a certain amount of glass fibers dries considerably faster in the paper machine than a pure cellulose fiber pulp, which is advantageous for economic reasons, since the rate of manufacture can thereby be increased.

After mixing, the fiberglass slurry is introduced into a fabric vessel.

In another vessel, a 3% cellulose fiber slurry of bleached birch pulp is prepared. To this 25 is added 5% sodium water glass binder - with the S i / Na ratio 3.4 to 1 - calculated on the total amount of fiberglass and cellulose fiber slurry and containing a carbamide amount of 1.5% of the binder amount and a propylene glycol amount of 0 , 3% of the bind-30 average. The function of the water glass binder is partly to reduce the moisture content of the fibers, ie. to make them more water repellent and partly to reduce the pore radius, ie. filling the pores in the sheet so that the pore diameter is reduced and fluid penetration is made more difficult.

The fiberglass slurry is added and mixed with the cellulosic fiberglass slurry. The proportion of glass fibers included in the composition is up to 10% by weight of the total amount. The mixture of cellulose fibers, glass fibers and water glass binder is alkaline, i.e. The pH is up to 9.0-9.5. By way of comparison, at this stage, a usual cellulose fiber mass usually has a pH of up to 4.5. No wetting agent or alum is added to the slurry, and there is no increase in temperature as in conventional manufacture.

The resulting slurry then passes through a cone mill and is routed in a conventional manner through the inlet box of a paper machine onto a wire.

A fiber product prepared in the manner described above has advantages above all of very good tear strength and very good printing properties, e.g. for multicolor printing, which is due to a good dimensional stability between the fibers in the product. The quality can also be very appropriate, e.g. for packaging, because of its good formability.

EXAMPLE 2

This test was carried out in exactly the same manner as the sample of Example 1, but with 30% admixture of mineral wool fibers, 10% water glass binder and 60% 25 cellulose fibers.

With the increased admixture of mineral wool, drying occurred faster than in the first example.

The paper got good dielectric properties, good strength against wear and against tensile and impact.

The shrinkage and contraction ability was negligible.

EXAMPLE 3

The test was carried out in the same way as the previous two, only with altered proportions of the components. In this case, 90% mineral wool fibers were blended with 5% water glass binder and 5% cellulose fibers.

The paper produced had good properties in terms of low combustibility and flammability and good thermal stability, and it was additionally resistant to mold.

EXAMPLE 4

In this fourth test, which was also performed in the same way as the others, 50% mineral wool fibers, 10% water glass binder, 5% melamine resin and 35% cellulose fibers were used.

The specific properties of this quality were good bending properties and a very smooth surface.

As can be seen from the examples, by varying the amount of mineral wool fibers, cellulose fibers and water glass binder, paper grades with different properties can be obtained. Thus, by mixing large percentages of mineral wool fibers - 20 attempts have been made to mix up to 95% by weight - paper grades with e.g. excellent fire retardant properties.

Experiments with up to 30% by weight of water glass binder have also been performed with good results.

In the examples given above, different types of paper grades have been prepared. However, the invention is not limited to fiber products alone in the form of relatively thin sheets, such as cardboard, cardboard and the like, but may well comprise a product up to a few centimeters thick in the form of felt.

In the examples given, carbamide and propylene glycol are added to the binder, but of course, said substances can equally well be added to suspension 35 separately.