NO142135B - USE OF A CELLULOSE FIBER MATERIAL IN TISSUE OR TRICOT FORM AS FREE-HANGING ROOF OR IN-WALL COATING - Google Patents

Description

In recent years, the technique of freely suspending ceilings in houses has undergone a development in several respects. The oldest technique consisted of stretching a weave, e.g. of jute, cotton or other cellulosic fiber, by hand and then painted, usually with white paint. The method has been improved by replacing the woven fabric with an elastic plastic film that is easier to tighten up and withstands settling in the house better, and which does not need to be painted, as it already has a seal. white, dense surface. A further improvement consists in these foils being swollen before installation using a swelling agent which is allowed to evaporate after hanging so that the foil shrinks and tightens by itself. By mixing glass fibers or other non-flammable fibers into the plastic film, it is achieved that it does not fall down in the event of a fire, but that, despite the mixing of stiff, non-swellable fibers, it retains its ability to swell in the solvent and then to shrink to full tightness after installation of the ceiling.

Several attempts have been made to tighten up tissue seams of e.g. jute or cotton in a similar way after they have first been swollen in water. However, all these attempts have been unsuccessful, because the threads in these weaves, as with all natural cellulose fibers, have an extremely insignificant swelling in their longitudinal direction,

while the swelling in the transverse direction of the threads, on the other hand, is significant. It has therefore not been possible to realize the swelling in the surface extent of the fabric which is a prerequisite for the method's application when erecting ceilings.

It has now been established the surprising fact that the cellulose fiber material in woven or tricot form based on the cellulose form cellulose II meets the aforementioned requirements very well, and thus according to the invention can be used as free-hanging ceiling or interior wall cladding with the property of swelling in water and assembly to be able to tighten itself by shrinking in its surface during drying. If you thus produce webs of cellulose II fibre, these webs can be swollen in water, so that the surface area increases by tens of percent. Such a swollen fabric can be used in the same way as previously used plastic foils for setting up ceilings, which tighten themselves when shrinking when the water (swelling medium) has evaporated.

The most common types of cellulose II fiber materials are produced by processing cellulose I materials, e.g. with strong alkalis or other strong electrolytes in aqueous solution or with liquid ammonia, amines or quaternary ammonium compounds and then washing away the reagents or dissolving the cellulose and spinning fibers from it, e.g. according to the viscose or cuprammonium method, or also by regenerating the cellulose from fibers of cellulose derivatives, e.g. acetate cellulose, nitro-cellulose and more. Other methods consist of partially substituting the cellulose's hydroxyl groups with e.g. methyl, ethyl, hydroxyethyl, hydroxypropyl, carboxymethylaminoethylamidoacrylic groups and more.

In most of these methods, not only the degree of crystallinity of the cellulose changes, but also its crystal structure, and it changes into a form commonly called cellulose II.

The difference between the crystal structure of cellulose I and cellulose II consists primarily in the fact that a crystal axis of the elementary cell is elongated in cellulose II, and that the angle between two crystal axes is simultaneously reduced. Different authors indicate different values which Treiber in his book "Die Chemie der Pflanzenzellwand", page 157 (Berlin 1957) has compiled into the following mean values:

The elementary cell is therefore somewhat more "loosely packed" in cellulose II than in cellulose I and should therefore be somewhat better available for swelling.

The degree of crystallinity, which is expressed as a percentage of crystalline material calculated on the total amount of cellulose in the fibres, varies with different cellulose materials. Different measurement methods also give different results, as will be seen from the following tables.

Phillipp, Nelson and Ziifle in "Textile Research Journal", 17, 585 (1947) give the following values for the crystallinity of various celluloses, as measured by acid hydrolysis:

P. H. Hermans and A. Weidinger state in "Journal Polymer Sei", 4, 135, (1949); 5, 656 (1950); 6, 533 (1951) the following values for the crystallinity of cellulose fibres, measured partly from X-ray diagrams, partly using density determinations:

It has also been shown to be essential in order to achieve large surface swelling of the fabrics that one maintains a low or moderate degree of orientation of the cellulose fibers used. Such an orientation is achieved both by mercerization of cellulose fibers and by spinning dissolved cellulose in that the fibers are stretched during the process. When producing fibers for the present purpose, this stretch should therefore be avoided or kept to a moderate size.

To achieve special effects, e.g. with regard to fire properties, the cellulose fibers can be mixed with fibers of other material, e.g. mineral fibres. This can happen either during spinning, when yarn is spun from mixed fibres, or during weaving, when threads of different fiber material are used in the same weave.

Before or after weaving, the fiber material should be treated with flame retardant substances which ensure that the weave cannot burn, but only chars if it is exposed to fire. Examples of such substances are phosphates, phosphites, phosphonium compounds, borates, bromine or chlorine compounds, antimony compounds and so on.

The weaves can also be coated with different plastic materials in the form of solutions, emulsions or foils so that the product e.g. should have a denser surface, better flame resistance or other desired properties. The plastic materials should be swellable in water, so the plastic layer follows the weave during the swelling of the cloth.

In the following, some design examples will be given.

Example 1

A cotton fabric is dipped for 5 minutes in an 85°C hot, 3% solution of sodium hydroxide in water. It is then dipped for one minute in a 25°C hot 20% solution of sodium hydroxide in water, after which it is immediately freed of all lye by rinsing with water. During the entire process, one avoids stretching the cloth more than what is needed for its transport through the baths.

After careful further washing out of all lye residues, the fabric is impregnated with a solution of 10 parts diammonium orthophosphate and 30 parts urea in 60 parts water. After the excess solution has been squeezed out, the fabric is dried for 13 minutes at a temperature of 160°C. It is then washed in water and dried. This flame retardant treatment means that the fabric cannot sustain combustion, but in the event of a fire will only be charred to a heavily ashed coal shell. The fabric is sewn together in pieces of a suitable size for ceilings using cotton thread that has been similarly flame retardant treated, or glass fiber thread. The fabric is then swollen in water and fixed side up against the wall at the right height under the ceiling of the room where it will serve as a ceiling. It then does not need to be fastened, but is simply hung up loosely like a sack. When the water evaporates, the tissue shrinks and tightens by itself.

You can also coat this fabric with plastic to get a

more fireproof product. The following example constitutes an embodiment of this:

Example 2:

A fabric according to example 1 is coated on one side with the following paste:

8 parts ethyl hydroxyethyl cellulose

7 " triethanolamine

4 " triaminotriazine

5 " pentaerythrite

7 "- ammonium polyphosphate

3 titanium dioxide

0.5 " oxaldehyde

2.5 formic acid

63 " water

The coated surface is sprinkled with 3 cm long glass threads to a weight of 20g/m^ and is then dried in an oven at 100°C. After drying, the cloth is coated again on the same side with the same paste and dried once more in the same way.

The resulting cloth is cut into pieces of suitable size, moistened in water to maximum swelling and set up as a ceiling in the same way as indicated in example 1.

The coating placed on the fabric has the property that in the event of a fire it produces a strong coal foam that is very difficult to ash.

This coal foam acts as a heat insulator and thereby protects the parts of the building above from heating up so strongly that ignition occurs.

The ethyl hydroxyethyl cellulose has changed into a water-insoluble form during the reaction with the oxaldehyde, but is still swellable in water. The ceiling can therefore be washed after installation if necessary.

Example 3

Staple fibers are produced from viscose cellulose using negligible stretch during spinning. 95 parts of these fibers are mixed with 5 parts of aluminum silicate fibers with a fiber diameter of 2.5 ^1, which are carded and spun into a yarn with coarseness no. 30. The yarn is then woven into a fabric with 10 threads/cm in the warp and weft direction. The glass threads make up every tenth thread in both the warp and weft direction. The fabric is flameproofed with ammonium phosphate and urea in the same way as in example 1. You can also, as in example 2, coat it with plastic mass. You then do not need to sprinkle it with glass threads, as the aluminium-silicate threads which are already tensioned into the yarn give the fabric sufficient load-bearing capacity in the event of a fire, so that it will form a continuous coal foam mineral fiber mat.

Example 4

A 400 denier viscose silk thread, which has been produced under negligible stretch during spinning, is woven together with an equally coarse glass fiber thread into a weave with 10 threads/cm in both the warp and weft direction. The glass threads make up every tenth thread in both the warp and weft directions. The fabric is flameproofed with ammonium phosphate and urea in the same way as in example 1.

It is then ready to be used as an inflatable ceiling. It can also be coated with plastic mass in the same way as stated in example 3 for use as an ignition protective ceiling.

When the shrinkage is greater than the swelling, these fiberglass threads, which do not participate in either swelling or shrinkage, do not prevent the use of the fabric for self-tensioning ceilings. You can of course increase the shrinkage effect in these by leaving the viscose silk thread moist already during weaving. When shrinking after installation of the roof, the glass threads give a certain ripple effect which can be used for decorative purposes.

Example 5

From a thread produced in accordance with example 3, a tricot fabric is produced which is then flame-retardant treated in accordance with example 3, after which the fabric is coated with plastic mass in the same way as according to example 3.

The tricot weave has the advantage over the woven fabric that, in the case of complicated room shapes, it has less tendency to give rise to wrinkles or distortions in the fabric surface during its own tightening (shrinkage).

One can also knit the tricot fabric from viscose silk thread, produced in accordance with example 4, and then replace part of the silk threads with glass fiber thread, so certain threads in the tricot fabric will be made up of glass fibers, which are then coated with plastic mass in the same way as mentioned-in example 3.

Example 6

Cotton is treated with a solution of 2-aminoethylsulphuric acid

and sodium hydroxide in water and heated to obtain an aminoethyl cellulose with a degree of substitution of approx. 1.2. After being washed clean for a reaction solution, product-t is then treated with tetrakis-hydroxymethylphosphonium chloride and ammonia in aqueous solution, washed and dried. The resulting fiber is mixed with;

about. 5% fiberglass with stack length 2 cm and diameter 5 \u and carded out. The resulting fiber pile is glued in a dot pattern with melamine glue, dried and cured at an oven temperature of 105°C.

The resulting product, which is of the non-woven cloth type, can, after swelling in water, be used for setting up ceilings in the same way as stated in the previous examples.

Example 7

Bleached sulfate cellulose from pine is aminoethylated and phosphonium-treated in the same way as the cotton in the previous example. A sheet of paper with a gram weight of 50 is produced from the resulting fiber.

On the wet sheet sprinkle twisted rayon threads (length 3 cm, roughness

840 denier) produced in the same way as in example 4 and flame retardant treated by aminoethylation and phosphonium treatment as well as finished with polyethyleneimine treated with tetrakis-hydroxymethylphosphonium chloride, and glass fiber threads of the same length and denier number, twisted from glass fibers with a diameter of 5 u and finished on

the same way as the rayon threads, assuming a mixing ratio between rayon and glass threads of 3:1. The wire layer has a gram weight of 75.

On top of this layer of rayon and glass threads, a further suspension of the above-described aminoethylated and phosphonium-treated cellulose fiber is poured, so that together with the thread layer and the first sheet it forms a paper with a gram weight of 175. This sheet is impregnated with a solution of ethyl ethoxyl cellulose

and oxaldehyde in water, squeezed off and dried. The resulting sheet can be used as a ceiling in the same way as in previous examples.

You can also cover it with a mass of the same type as

1 example 2 and use the formed product as a ceiling according to the above.

Claims (2)

1. Application of a cellulose fiber material in woven or tricot form based on the cellulose form Cellulose II as a free-hanging ceiling or interior wall covering with the property, after swelling in water and assembly, to be able to tighten itself by shrinking in its surface during drying. 2. Use of cellulose material as specified in claim 1, coated with a water-swellable plastic mass.