CA1188874A - Process of manufacturing a heat- insulating building board - Google Patents

Abstract

PROCESS OF MANUFACTURING A HEAT- INSULATING BUILDING BOARD

Abstract of the Disclosure A process of manufacturing a heat-insulating building board is disclosed, which comprises at least one plate of heat- insulating material, which is enclosed by a reinforcing material,which ensures the required strength.
The reinforcing material is introduced as a pulp into a vertical mold so as to fill the latter only in part. The plate of heat- insulating material is then preferably centrally immersed into the partly filled mold and is held in position so that the plate of heat- insulating material displaces the pulp and is enclosed by it.

Description

_ackground of the Invention This invention relates to a process of manu-facturing a heat-insula-ting building board, which consis-ts of at leas-t one pla-te of heat-insulating material, which is enclosed by a reinforcing material which ensures the required s-treng-th.

The desire for energy-saving buildings and for a subsequent applica-tion of heat-insulating layers in residential buildings has resulted in an enormous increase of the demand for various insulating ma-terials, such as insulating boards and insulating mats. The desire for elemen-ts and boards which are weather- and ire-resistant and dimensionally stable and have a high - bending strength is continuously increasing.

There are numerous effective insulating materials in the form of elements and boards bu-t none are known which are weather- and fire-resis-ting and dimensionally stable and have a high bending strength.
For this reason it is not possible to use a material of one kind for various purposes/ e.g., for walls and ceilings of a garret and for insulating a flat roof, a facade or a wall or for making a partition.
The requirements are so different tha-t -the properties of a single matexial are not sufficient. Austrian Patent Specification 322,165 describes process of manufacturing boards, plates or shaped eIements which have a heat-insulating core that is surrounded by a hydraulic binderr such as gypsum. The process is used for the continuous manufacture of a strip ~hich is, eOg., 0.6 meters wide and 7 centimeters high and which is finally cut into plates or boards having a desired length so that the binder does not cover the end faces.
The process comprises a plurality oE steps. The core is first inserted into a mold, which consists of a con-veyor belt and laterally disposed rubber belts. In the next s-tep the laterally disposed rubber belts diverye and the gypsum pulp is poured into the laterally ~ mab/ ~

widening space so that the core is lifted by bouyancy until it engages a pressure roller, which limits the lifting of the core. The gypsum plaster is introduced in such a manner -tha-t it encloses the core to about one-half of its height. When the gypsum plaster has hardened, the pressure roller is removed and additional gypsum pulp is poured in until the la-tter has risen to the upper edge of the laterally disposed rubber belts and entirely covers the core. That second layer is then hardened. Because the second gypsum layer is not applied until the first gypsum layer has hardened, a monolithic joint between the two layers is not obtained so tha-t the mechanical strength is lower than that which would be ensured by a homogeneous joint.

Summar~ of the Invention The disadvantages encountered in the manufacture of building boards of the known kind can be eliminated by the heat-insulating building board according to the invention.

It is an object in the invention to provide a proc ss of manufacturing individual heat-insulating building boards which consist of a composite that meets the above-mentioned requirements, has a high bending strength and can be made in a small number of working steps.

The process of manufacturing a building board of the kind mentioned first hereinbefore is characterized according to the invention in that the reinforcing material is introduced as a pulp into a vertical mold so as to fill the latter only in part and -the plate is then preferably centrally immersed into the partly filled mold and is held in position so that the pulp is displaced by the plate and encloses the latter.

According to another feature of the invention the p]ate and/or the mold is vibrated as the plate is immersed into the pulp so that the friction between the ~ 2 mab/ ~
.~
~ ~.

~ 3~

plate and the pulp is reduced and -the wettiny of the plate by the pulp is improved. For improved wettiny, the invention teaches -to moisten the plate and/or to apply a wetting agen-t -to the plate before it is imme-ised into the pulp. Another feature of the invention resides in that the reinforcing material contains binders which harden hydraulically and/or with carbonation and are mixed with water to form a pourable pulp, which when hardened has a density of 400 to 2500 kg/m3.

According to another feature of the invention the reinforcing material contains inorganic and~or organic synthetic fibrous materials and/or natural fibrous materials, fiber mates, fiber meshes or the like, as well as water-soluble modified plastic materials, air-entraining agents, foam stabili~ers, fine-grained admixtures and color pigments.

2Q An additional feature of the invention resides in that the plate consists of synthetic organic products, such as polystyrene, polyurethane, foamed phenol resin, foamed rubber or similar foams, which have in the dry state a density below 200 kg/m , preferably below 40 kg/m3.

Also in accordance with the invention the plate may consist of natural organic products, such as straw, reed, coconut fiber, wood fiber, sawdust, cork, ri~e shells, raw cotton or the like, which in the form of plates have in the dry state a density below 400 kg/m3, preferably below 200 kg/m3.

According to a further feature of the invention, the plate consists of inorganic products, such as expanded perlite, vermiculite, expanded clay, expanded shale, granulated ash, foamed silicate, foamed water-glass, glass wool, mineral wool, crushed foamed slag or the like, which in the form of plates have in the dry state a density mab/ ~J~r~
~' below 600 kg/m3, preferably below 300 ky~m3.

Also in accordance with the invention the plate is formed at its ends with steps or with a tongue and groove. These formations may subsequently be formed by milling.

In one aspect the invention provides a process for manufacturing a heat-insul.ating building board, which includes at l~ast one plate of heat-insula-ting material enclosed by a reinforcing material which ensures the required strength, said method comprising: providing a mold; orienting the mold with its longest interior dimension ex-tending vertically;
introducing a hardenable reinforcing ma-terial as a pulp into the mold so as to fill the mold to a pre-determined volume so tha-t the mold is filled only in part; di~pl~ing the plate into the L~artly filled m~ld and holding it in posi~tion so that the pulp is displaced hy the plate and encloses the latter; permi-ttin~ the reinforcing material to ~arden~ and removing the finished board from the ~old.

Illustrative embodiments of the invention will now be explained with reference to the drawings.
.
Brief Description of the Drawings Figure 1 is a -transverse sectional view taken at right angles to the longitudinal direction of the building board and shows a first illustrative embodiment of a building board according to the invention.
Figure 2 is a similar view showing a second embodiment of a building board according -to the inven-tion;
Figure 3 is a similar view showing a third illustrative embodiment of a building board according to the invent.ion;

mab/`f Figure 4 is a similar view showing a fourth embodiment of a building board accordiny to the invention;
Figure 5 is a similar view showing a fifth embodiment o a building board according to the invention;

Description of the Preferred Embodimenks Figure 1 shows a heat-insulating plate 1, which just as in the o-ther embodiments, shown in Figures 2 to 5, may consist of syn-the-tic organic products, such as foamed polystyrene, foamed polyurethane, foamed phenol resin, foamed rubber or similar foams, which have in a dry sta-te a density ~elow 200 kgJm3, preferably below 40 kg/m3. Al-ternatively, the plate 1 may consist of natural organic produc-ts, such as s-traw, reed, coeonut fiber, wood fiber, sawdus-t cork, rice hulls, raw cotton or the like, which in the form of plates have in a dry state a density below 400 kg/m3, preferably below 200 kg/m3. These materials can also ; be used for making the plate 1 shown in Figures 2 to 5~

Finally, -the plate 1 shown in Figures 1 to 5 may be made from inorganic products, sueh as expanded - 4a -mab/J~-rJ~

perlite; vermiculite, expanded clay, expanded shale, granulated ash, foamed silicate, foamed wa-ter-glass~
mineral wool, crushed ~oamed slay, glass wool or the like in the form of a prefabricated element consisting of any of these produc-ts or a combination thereof.

The plates can be prefabricated in that the abo~e-mentioned materials are processed together with an inorganic binde~, such as Port:land cement, high-alumina lO cement, aluminum cement, hydrophobic cement, gypsum, hydraulic lime, slaked lime, or with other binders, such as spent sulfite liquor cellulose products, or water-soluble plastics materials, to form prefabricated plates.

The material 2 surrounding the plate l serves as a support and is dimensionally stable and fire- and weather-resisting. It may preferably consist of binders whîch harden hydraulically and/or with carbonation, such as Portland cement, natural cement, slaked lime, hydro-20 phobic cement, white cement, or plastic-modified forms of said materials in a pure form or with fine-grained frost-and fire-resisting admixtures, preferably in particle siæes below lO mm. To improve the heat insulation, the invention calls for incorporating an air-entraining agent in a cement paste or mortar obtained by mixing said materials with water. Fibers 3 may be admixed to improve the dimensional stability and the bending strength. The fibers 3 consist of individual or interlaced inorganic and/or organic synthetic and/or natural fibrous materials, 30 fiber mats, fiber meshes or the like, which in the process according to the invention are added during the preparation of the cement paste or mortar or are added thereto in the mold before hardening takes place.

In the embodiment shown in Figure l, the mold used to manufacture the building board may have in its bottom a trapezoidal recess so that the corresponding portion of the building board is formed with a trapezoidal tongue.
~0 A corresponding groove can be formed in the upper end face of the building board, e.g., in that the mold is provided beEore the hardening of the mater-ial ab/ Y~1 7~
with a cover which has a correspondiny -trapezoidal recess.
In -that case much fewer dowels will be required to fix the insulating board to masonry and the fixing means will not injure the visible surface.

The building boards shown in Figure 2 may be formed in a similar manner with a semicircular tongue.
The complementary semicircular groove may be ormed, e.g., in the heat-insulating plate 1. The joints be-tween adjoining building boards may be improved in accordance with Figure 2 in that a fixing strip 3a consis-ting, e.g., of fibrous material, is embedded in the reinforcing material. Alternative fastening means consist of individual lugs, plates or hooks 3b, which are anchored in the building board, as shown in Figure 3. Where a building board is provided with such additional fastening means, the adjoining board will be provided with a mating recess 4 for accommodating the fastening means. The board may be provided on its exposed surEace with a colored and/or structured layer, which may be obtained by an addition of fine-grained admixtures and/or color pigments to the material 2. In the embodiment shown in Figure 3, the bottom surface of the mold is complementary to the recess 4 and the protruding plate 1. Besidesl the cover of the mold is provided with a recess which corresponds to the width of the plate 1.

In the embodiment shown in Figure 4, the plate 1 is pro~idedJ e.g., with dovetail grooves and is immersed into the pulp in contact with the right-hand inside surface of the mold. The mold is provided at the bottom with a step 4a so that the material 2 does not reach the bottom. As a result, the finished building board has a recess 4a, which can receive the protruding portion 5 of the hardened material 2 of an adjoining building board as the building boards are assembled. The cover of that mold has a recess which has the same width as the plate 2 so that the material 2 Eorms the protruding portion 5 at the top.
The embodiment shown in Figure 5 is similar to that of Figure 3 but comprises two plates 1. The mold and its cover are so shaped that two recesses are obtained ,~ mab/~¦1 on the top end face of the finished building board and may receive two pla-tes 1 protruding from the lower end face of an adjacent building board as the building boards are asser~led.
The process according to the :invention for the manufacture of heat-insulating boards will now be e~plained more fully with reference to examples, to which the invention is not restricted.
Example 1 The ma-terial 2 consisted of a cement paste which was based on Portland cement and contains 0.1~ air-entraining agent and 2.0% by volume fibers. That paste was stirred under superatmospherie pressure in a forced circulation mixer rotating at high speed to form a mix of high porosity, which was poured into a vertical mold.
The mold was filled to such an extent that it was filled to its top edge by the subsequent immersing of a poly-styrene board 5 cm thic7c into the material 2 so that the latter was displaced. The extremely lightweight polystyrene plate 1 was held against floating up by a mounting provided on the end facès or the longitudinal edges and against a lateral slipping by a guide. The plate 1 was held in the mold until the material 2 had hardened. The mold caused the material 2 to form a tongue and groove. When the material 2 had hardened, the resulting building board ha~ing dimensions of, e.g., lOOx60x8 centimeters, had a spacific gravity of 300 kg/m3 and the average ultimate load with an effectîve span of 50 cm amounted to 80 kg.
Example 2 To make the material 2, a basic mixture con-sisting of 9 parts by weight of foamed polystyrene spheres 0.2 to 3.0 mm diameter and 91 parts by weight was stirred with water and 0u3% air-entraining agent in a forced circulation mixer. The material was poured into a vertical mold, into which a close-mesh glass fiber mat was immersed, e.g., at the edge, as a plate 1. The pressure applied by the material 2 forced the glass fiber mat against the wall of the mold so that the mat served virtually as a filter preven-ting a movement of the poly-styrene particles to the outside. This resulted in the formation of an outer layer consisting of cement paste reinforced with glass Eibers, ~ rnab/ Y,~-1 ,~ ~

- , - ~ -a ~'7~

and of a core layer consisiing of cement-bonded polystyrene.
The plate 1 remalned in the mold un-til the materia~ 2 had hardened. A building board made in this manner and having dimensions of 150 x 60X 8 centime~ers had a specific gravit~y of 350 kg/m~.and wi-th an effective span of 50 cn had an average ultimate load of 100 kg.

Example 3 Formula for material 2:
Expande~ perlite, particle size 0~0 to 3~0 mm 5.0 ~/0 by weight Expanded clay (500 g/liter), particle size 3Ø to 10.0mm 95.0 % by weight Cement content 350 kg/m3 Water cement ratio 0.7 Air-entraining agent: 0.3 % by weight of the cement.
Mixing was effected in a forced circulation mixer so that the cement paste which contained the perlite was prepared first and the expanded clay was subsequently admixed for a short time. rrhe resulting mix was poured into a vertical mold. A mat of synthetic fibers was{sub-sequently immersed int~ the mold and held in po~etio~ by the means described in Exarnple 1. The resulting building board having dimensions of 120 60 8 centimetPrs had a specific gravity of 600 kg/m3 and wi-th an effective span of 50 cm had an average ultimate load of 200 kg~
In the examples mentioned above) the heat-insulating material could be introduced into the mold first 7 fol~owed by the introduction of the reinforcing--material as a pulp. But air-bubbles may then be included and would reduce the strength of the finished building board. The danger is avoided by the process according to the invention, which results in an intimate hond between the two materials so that a high strength is ensured.
other advantages afforded by the building board according to the invention over conventional boards reside in that they have a very wlde field of applica-tion because they resis-t water and fire and have a high bending strength. For instance, they can be used to insulate basement walls and facades, or as lost formwork in the making of concrete walls and f~oors, as walls and ceilings of garrets, and as partitions between rooms, also ins-tead of wood in 7~

the erection of barns ahd huts9, where the fire risk is very high. In all these uses, all embodlments have a sur.face which corresponds to a final plaster coat or may be used as a plaster base for a ready-mixed colored external plsster.

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for manufacturing a heat-insulating building board, which includes at least one plate of heat-insulating material enclosed by a reinforcing material which ensures the required strength, said method comprising:
providing a mold;
orienting the mold with its longest interior dimension extending vertically;
introducing a hardenable reinforcing material as a pulp into the mold so as to fill the mold to a predetermined volume so that the mold is filled only in part;
dipping the plate into the partly filled mold and holding it in position so that the pulp is dis-placed by the plate and encloses the latter;
permitting the reinforcing material to harden; and removing the finished board from the mold.

2. A process according to claim 1, wherein one of the plate and the mold is vibrated as the plate is dipped into the pulp.

3. A process according to claim 1 or 2, including the step of applying a wetting agent to the surface of the plate before the plate is dipped into the pulp.

4. A process according to claim 1 or 2, wherein the reinforcing material contains binders which harden hydraulically or with carbonation and which are mixed with water to form a pourable pulp, which when hardened has in a dry state a density of 400 to 2500 kg/m3.

5. A process according to claim 1 or 2 wherein the reinforcing material is selected from the group consisting of natural fibrous materials, fiber mats, and fiber meshes, and contains water-soluble modified plastic materials, air-entraining agents, foam stabilizers, fine-grained admixtures and color pigments.

6. A process according to claim 1 or 2, wherein the plate consists of synthetic foamed organic materials selected from the group consisting of poly-styrene, polyurethane, phenolic resins, and rubber having in a dry state a density below 200 kg/m3.

7. A process according to claim 1 or 2, wherein the plate is formed from natural fibrous products selected from the group consisting of straw, reed, coconut fiber, wood fiber, sawdust, cork, rice hulls, and raw cotton having in a dry state a density below 400 kg/m.

8. A process according to claim 1 or 2, wherein the plate is formed from inorganic materials selected from the group consisting of expanded perlite, vermiculite, expanded clay, expanded shale, granulated ash, foamed silicate, foamed water-glass, glass wool, mineral wool, and crushed foamed slag, which have in a dry state a density below 600 kg/m3.

9. A process according to claim 1 or 2, wherein the molded board has at opposed ends a tongue and groove formed by the mold.

10. A process according to claim 1 or 2, wherein the molded board has its opposite ends a tongue and groove which have been subsequently formed by milling.