NO129460B - - Google Patents

Description

Method of manufacture of

insulation materials with low specific gravity.

The invention relates to a method for production

of insulating materials with a low specific weight, whereby porous plastic particles are brought into water-containing inorganic binders and these mixtures are hardened, and the method is characterized by using aqueous alkali silicate solutions as binder,

to which such substances are added, which react slowly with the alkali silicates during precipitation of insoluble compounds and solidification of the mixture, these substances being selected from among tetrachlorophthalic acid, alkali borates, organic acid esters, organic acid anhydrides

there, silicofluorides of calcium, zinc, sodium and magnesium, or sodium boron fluoride, whereby as porous plastic particles an-

those which under the chosen conditions do not undergo any increase in volume during solidification, namely of polystyrene or polystyrene copolymers or polyvinyl chloride or copolymers of vinyl chloride and vinylidene chloride.

It is known that for the production of building elements with a low specific weight, one can mix fine-grained, porous thermoplastic plastic particles with closed pores, with aqueous binders, shape the mixtures and then allow them to harden. Substances known in the construction industry, such as cement, plaster or mortar, are used as binders. Instead of these inorganic binders, organic binders are also suitable, e.g. aqueous solutions of adhesive or hardenable synthetic resins, e.g. 'urea/formaldehyde condensation products. These binders have the disadvantage that they harden relatively slowly, so that the production of these insulating materials requires considerable time. The insulating materials also cannot withstand a lasting heat stress at very high temperatures, e.g. 800 to 900°C. If organic binders were used during production, they burn to a high degree.

When using the aforementioned inorganic binders, the mechanical strength of the insulating materials is destroyed, e.g. by the cement becoming brittle. furthermore, these insulating materials have the disadvantage that they have low breaking strength when they exhibit a lower bulk density, in other words when the proportion of porous synthetic resin particles is very high.

According to a proposal that does not belong to the technique

state and which is written by the patent holder, insulation materials with a low specific weight can be produced by mixing inflatable plastic particles with aqueous inorganic binders and allowing the mixtures to solidify when alkaline silicate-containing aqueous solutions are used as binders, with any suspended therein,

solid aqueous alkali silicates, and foams these mixtures into a homogeneous foam at a temperature higher than the softening point of the foamable plastic, possibly after they have become rigid at temperatures below the temperature at which the finely divided plastic foams.

It now turned out that such insulating materials which are produced by introducing porous plastic particles into water-containing inorganic binders, and where these mixtures are brought to solidify or harden into shaped bodies, can also be advantageously produced by using aqueous alkali silicate solutions as binders, which such substances are added which react slowly with alkali silicates during the precipitation of insoluble compounds and thereby cause the mixture to solidify or harden, whereby porous plastic particles are introduced which, under the chosen conditions for transfer to a solid or solidified form, do not undergo any increase in volume.

To produce these mixtures, the simple

components, namely the porous plastic particles, the alkali silicate solutions and the additives, which react with the alkali silicates, as homogeneously as possible. The individual components are used in such quantities that a relatively loose mass is formed which can be easily poured and which can be filled into molds and the like to be compressed into compact molded bodies.

As substances which react slowly in water with the alkali silicates during the precipitation of insoluble compounds, examples can be mentioned: tetrachlorophthalic acid, alkali borates, organic acid anhydrides, e.g. phthalic anhydride, organic esters, e.g. propyl acetate. It is advantageous to add substances such as silicofluorides, e.g. calcium silicofluoride, zinc silicofluoride, sodium silicofluoride and magnesium silicofluoride or sodium boron fluoride.

These substances are added to the mixtures in such a quantity that in it

at least a significant part of the silicic acid proportion in the alkali silicates used is precipitated.

By varying the added amounts of porous plastic particles, insulation materials with different specific weights can be produced. If you choose a very high proportion of these particles, e.g. up to 95% by volume, insulating materials with a density of about 50 to 250 kg/m 3 are obtained. Of course, by reducing the proportion of porous plastic particles, it is also possible to produce insulating materials with a higher density, for example up to 600 kg/ m<3>and a correspondingly higher breaking strength.

Porous plastic particles are used, for example, of polystyrene or polystyrene copolymers, for example of styrene and acrylonitrile, acrylic acid, butadiene and the like. These particles are produced in the usual way by heating particles of these plastics, which contain low-boiling liquids or gases as propellants, whereby the particles foam up. Furthermore, porous plastic particles based on vinyl chloride or copolymers of vinyl chloride and vinylidene chloride also come into consideration.

It is advantageous to add flame retardant compounds, e.g. inorganic halogen compounds or mixtures of chloroparaffin powder and antimony trioxide, to the porous plastic particles.

Sodium or potassium silicates in any concentration are preferably used as alkali silicate solutions.

In general, solutions of common merchandise are also used

a concentration of e.g. 38°Be. The molar ratio sodium oxide: silicon dioxide in the alkali silicates can be from 1:1.2 to

1:3.8. In addition to the substances mentioned, fillers can also be added to the mixtures, e.g. talc, chalk, kaolin, glass powder or quartz powder. In particular, zinc oxide comes into consideration as a filler.

It is essential that the components are mixed, possibly under strong cooling, within a short time, to avoid solidification while the mixture is in progress. The resulting mixtures are immediately filled into the molds or placed on endless belts where they are allowed to remain until a hard and pressure-resistant mass is formed. The aforementioned mixtures already solidify at room temperature. In order to accelerate the hardening process, however, it is advantageous to heat the mixtures, whereby the temperature should not exceed the softening point of the plastic particles used. Due to the properties of the mixtures that they harden or harden already at room temperature, it becomes possible to provide walls and the like with an insulating layer in a simple way. For this purpose, the wall to be insulated is provided with a wooden formwork, and the cavity is filled with mixtures prepared according to the invention. In order to obtain particularly pressure-resistant insulating materials, it is possible to compress the mixtures before they solidify into molded bodies to about 10 to 90% of its conceivable volume. This is particularly advantageous when mixtures containing a very large proportion of porous plastic particles are used.

Insulating substances produced according to the invention can be used as insulating material both against cold and against heat. If they are exposed to high temperatures, as they will be in the event of a fire, then their organic part burns. But what will remain is a porous and mechanically stable skeleton of the inorganic components, which, due to its structure, exhibits considerable resistance to the passage of heat energy. When using an excess of additives compared to the stoichiometrically necessary amount to precipitate the silicic acid, practically all the silicic acid is released from the alkali silicates, and since alkali silicates cannot practically be detected in the finished insulation materials, the materials have been produced according to the invention only little ability to absorb moisture or water.

These properties make the insulation materials suitable for many applications in the building industry. Depending on their room weight, they can be used instead of other foam materials, fiber materials, cork, wooden boards, plastic boards, hard rubber, lightweight concrete boards and the like. They can also be easily covered with metal, plasterboard, plastics, plaster, wallpaper and the like. In this way, laminate elements such as e.g. can be used as fire-resistant and insulating doors. As long as the insulation materials have a thickness of 15 mm and exhibit a bulk density of around 200 to 400 kg/m, such laminates can be classified as fire-retardant when tested according to DIN 4102. In the manufacture of laminates, of course, several insulation layers, produced in accordance with the invention, with different space weights, e.g. from 120 kg/m 3 and 350 kg/m 3, combined with each other.

Example 1

1a rapid mixer produces a mixture of the following ingredients within 3 minutes: 2,000 parts by weight of soda-water glass solution with a concentration of 39°Bé,

500 parts by weight of foamed polystyrene particles with

diameter 0.2 - 3 mm and as up-

shows a loose weight of 25 g/l,

400 parts by weight, sodium silicofluoride,

400 ■ parts by weight talc,

400 parts by weight of chlorinated paraffin in powder form with a

chlorine content of 75%,

100 parts by weight of powdered antimony trioxide.

This mixture contains 85.8 volume percent foamed polystyrene particles. It is immediately transferred to a perforated metal mold, the inner walls of which are lined with cloth, so that the loose mixture fills the mold completely. The shape has a length of 110 cm, a width of 57 cm and a height of 20 cm. In this the mixture is compressed to a height of 13 cm and is left in this state under a metallic lid which is kept at a constant height by means of a piston. This lid is somewhat smaller than the mold, so that a distance of about 1 mm remains between its outer edge and the walls. The mold is stored for 3 hours at a temperature of 70°c and then for 8 hours in a vacuum cabinet at a pressure of 50 Torr and the same temperature. After cooling, a highly pressure-resistant molded body with a bulk density of 180 g/l is removed from the mold. The resulting block is sawn with the aid of a band saw into individual slabs with a thickness of 2 to 4 cm, such as can be used as an intermediate layer in laminates.

Example 2

As described in example 1,. a loose mixture of the following ingredients is prepared: 1,750 parts by weight of hatron water glass with a concentration of 39°Bé\

300 parts by weight of foamed polystyrene particles with a diameter of 0.2 - 2.5 mm, which have a loose weight of 15 g/l,

200 parts by weight tetrachlorophthalic acid,

500 parts by weight of talc,

200 parts by weight chlorinated paraffin,

100 parts by weight of antimony trioxide,

300 parts by weight of borax.

This mixture contains 86.3 volume percent foamed polystyrene particles. The mixture is filled into a wooden formwork in front of a wall and sealed mechanically. After 24 hours, the wooden formwork is removed, and a layer is then left on the brickwork, which, after complete drying, has a density of 213 g/l.

Example 3

As described in example 1, a loose mixture of the following components is prepared:

1,600 parts by weight soda water glasses with concentration

39°Bé,

150 parts by weight potassium water glass with concentration

25°Bé,

89.25 parts by weight of foamed polystyrene particles with a diameter of 0.2 - 2.5 mm, and which have a loose weight of 21 g/l,

300 parts by weight chlorinated paraffin,

100 parts by weight of antimony trioxide,

250 parts by weight of magnesium silicofluoride."

This mixture contains 94.4 volume percent foamed polystyrene particles.

The mixture is filled in the form described in example 1,

and after compression to 85% of the original volume, it is stored for 10 hours at 70°c. There is a hard shape-

me with a density of 100 g/l, which has a thermal conductivity at 0°C of 0.03 5 kcal/mh °C.

Example 4

As described in example 1, a loose mixture of the following components is prepared: 1,750 parts by weight of soda ash solution with a concentration of 39°Be,

300 parts by weight polyurethane foam with closed cells,

which has been transferred to particles with a grain size of 2-6 mm, and which exhibits a loose weight of 40 g/l,

150 parts by weight sodium silicofluoride,

100 parts by weight tetrachlorophthalic acid,

300 parts by weight talc,

150 parts by weight chlorinated paraffin,

7 5 parts by weight of antimony trioxide.

This mixture is filled in a wooden mold consisting of door frames, which is 57 cm wide, 110 cm long and 20 cm high. After

the door frames have been removed, a form body appears, still loose,

but already firm enough to stand, which is stored for 24 hours at 20°C

and then another 24 hours at 30°C under a pressure of 15 Torr. The finished molded body has a bulk density of 375 g/l which is divided into plates of 4 cm width. When testing these plates according to DIN 4102

with shielding on both sides with 3 mm thick asbestos cement sheets, they achieve a heat resistance duration of more than 60 minutes.

Example 5

1a rapid mixer prepares at room temperature a mixture of the following ingredients: 2,000 parts by weight of soda-water glass solution with a concentration of 39°Be,

200 parts by weight of soda ash glass powder with grain size 0.2 - 1 mm, water content 16 percent by weight.

150 parts by weight sodium silicofluoride,

500 parts by weight of zinc oxide,

300 parts by weight chlorinated paraffin,

100 parts by weight of antimony trioxide,

425 parts by weight of foamed polystyrene particles with a particle size of 2-6 mm and a loose weight of 17 g/l.

The mixture is filled into a wooden mold, smoothed evenly and compressed to 40% of the original height. In this condition, the mixture is stored for 4 hours. A solid block is created that can be removed from the mold. This is stored for 2 days at room temperature and 5 days at 75°C. The block is cut using. a band saw 4 cm thick boards.

The foam material has a bulk density of 173 g/l, is well pressure-

and rub-resistant and has a smooth surface. By. storage in water, a weight increase of 3.12% after 24 hours can be determined, whereby an unchanged good compressive strength is still exhibited.

These boards are used to build up a laminate, where one side consists of asbestos cement boards and the other side of rigid gypsum boards. This laminate is distinguished by a very high flame resistance. Such plates can be used as insulation material of a completely general nature. By increasing the proportion of plastic particles, the room weight can also be significantly reduced, e.g. to 100 g/l.

Claims (3)

1. Process for the production of insulating materials with a low specific weight, by introducing porous plastic particles into water-containing inorganic binders and curing these mixtures, characterized in that aqueous alkali silicate solutions are used as a binder, to which such substances are added that react slowly with the alkali silicates during the precipitation of insoluble compounds and stiffening of the mixture, these substances being selected from among tetrachlorophthalic acid, alkali borates, organic acid esters, organic acid anhydrides, silicofluorides of calcium, zinc, sodium and magnesium, or sodium boron fluoride, whereby porous plastic particles are used which do not undergo some volume increase during solidification, namely of polystyrene or polystyrene copolymers or polyvinyl chloride or copolymers of vinyl chloride and vinylidene chloride. 2. Method according to claim 1, characterized in that before curing the mixtures are compressed from 20 to 90% of their original volume, and that the curing takes place in a compressed state. 3. Method according to claims 1 and 2, characterized in that the curing is carried out at higher temperatures.