LU86083A1 - COMPOSITE PANELS FOR BUILDINGS - Google Patents

Description

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COMPOSITE PANELS FOR BUILDINGS

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The present invention relates to composite panels for buildings, and in particular to a roof structure or a wall structure as well as to a method for promoting the adhesion of a cement mortar to an expanded polymer material.

The present invention relates more particularly to a composite panel for construction, this panel comprising a main body made of an expanded material with generally smooth skin and closed cells, this material comprising, on at least one of its surfaces, a protective cementitious lining material serving as ballast, adhering to this surface, these panels being suitable for use in the construction of roofings or roof linings and in the construction of internal or external walls. In particular, the expanded material is an expanded polymeric material with generally smooth skin and closed cells.

Composite panels have already been described, in particular those used in roofing roof structures, as for example in US patent 3,411,256. There is thus provided on the upper face of a waterproof membrane, an insulating layer of closed cell foam consisting of a series of insulating elements of closed cell foam, these elements forming joints between the adjacent elements. The insulating layer is also covered with a protective layer made of an inorganic material, such as mortar. These composite structures, however, suffer from ineffective bonding of the protective layer to the surface of the insulating elements, resulting in separation of the layers during normal handling and / or normal exposure to the weather. Such separation of the layers is due to the temperature cycle of the protective layer, due to the differences existing in the coefficients of expansion between the foam and the mortar. Another factor which probably contributes to this separation is the poor bonding of the protective layer to the generally smooth-skinned, closed-cell foam insulation, taking into account the removal of the known protective layers resulting in the development of stresses at the interface between the foam and the mortar.

In order to increase the adhesion between the mortar layer and the insulating layer, it has already been proposed to modify the mortar with a styrene-butadiene copolymer used in the form of latex. Although the presence of the styrene-butadiene latex in the mortar already improves the compatibility between the mortar and the insulating layer made of an expanded polymer, this is not yet sufficient to completely eliminate the problems of adhesion.

In order to physically reinforce the bonding and the adhesion of the layer of mortar to the insulating layer, it has already been proposed to cut notches in the insulating material or to emboss it by passing it along a roll having longitudinal projections. However, these techniques have the drawback either of reducing the thickness of the insulating layer, thus resulting in a non-negligible reduction in the insulating power, or of reducing the mechanical resistance of the insulating material, also favoring the appearance of microcracks which will be harmful to the overall strength of the composite material.

On the other hand, it has also been proposed to reinforce the mortar by incorporating fibrous material to maintain the integrity of the composition; in particular, it has been proposed; /. , - 3 - to add glass fibers. However, it has been found that after a certain time, the mortar promotes the disintegration of the glass fibers, rendering the composite panels unusable.

There is therefore a need for composite materials formed of an insulating layer and a cementitious layer having improved adhesion properties.

The object of the present invention is to provide a composite material which no longer exhibits the drawbacks mentioned above.

The present invention relates to a composite material, comprising an insulating layer and a mortar layer, in which the adhesion between these layers is significantly improved.

The present invention also relates to a composite panel comprising a layer of expanded material and a layer of mortar, this panel having excellent mechanical properties.

The subject of the present invention is also a. composite panel comprising a layer of expanded material, a layer of mortar and a layer of an organic resin providing adhesion between the two above layers.

The composite panel of the present invention comprising a main body made of somewhat generally smooth, closed cell expanded material and a protective mortar coating adhering to at least one surface of the main body of the expanded material by means of a layer. of an organic resin, is characterized in that the mortar coating comprises a cement chosen from Portland cements, metallurgical cements and pozzolan cements, a surfactant in an amount of 0.1 to 5% by weight based on cement, and polyolefin fibrillary films in an amount of 0.02 to 0.4% by weight based on the total weight of the mortar and in that the organic resin layer comprises an epoxy resin and an epoxy resin hardener , the thickness of '' - 4 - ι 4 the adhesion layer not exceeding 1 mm.

The present invention also relates to a method for promoting the adhesion of the cement mortar to the surface of the expanded material to form a composite panel, this method being characterized in that it comprises the steps which consist in - applying to the surface of the expanded material a layer of an epoxy resin containing a usual hardener of epoxy resins; c - apply a layer of cement mortar to the surface of the epoxy resin layer; - let the cement mortar harden.

The insulating layer of expanded material used in the composite panel of the present invention is a material with generally smooth skin and closed cells, which is practically waterproof. In particular, expanded polymer materials with generally smooth skin and closed cells are particularly advantageous.

As examples of expanded polymer having a closed cell configuration, mention may in particular be made of expanded, molded or extruded polystyrene, the foams obtained from styrene-acrylonitrile (SAN) copolymer or from styrene-methyl methacrylate copolymer, expanded polyvinyl chloride, expanded polyurethane, expanded polyethylene or even phenolic foams and the like. As examples of other materials which can be used, mention may in particular be made of ceramic foams and glass foams.

In the composite panel of the present invention, however, it is preferred to use expanded polystyrene. Generally, the expanded polystyrene used in the present invention is in the form of plates which have been ex-extruded and which have a thickness varying between approximately 3 cm and approximately 12 cm, and a density ranging between approximately 20 kg / m 2 and 50 kg / m ^.

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One of the important advantages of the present invention resides in the fact that the expanded polystyrene panels can be used directly to form the composite material, without having to undergo additional operations, such as cutting notches or embossing.

The composite panel of the present invention then comprises a layer of organic resin which is spread over at least one surface of the panel of expanded polymer.

The Applicants have now unexpectedly found that excellent adhesion can be obtained between the insulating layer and the mortar layer, using as an organic resin an epoxy resin alloyed with a usual hardener of epoxy resins.

The epoxy resins used in the present invention can be saturated or unsaturated, aliphatic, cycloaliphatic or heterocyclic. They can be of monmeric or polymeric nature. It is preferable that the epoxy resins contain glycidyl ether or glycidyl ester groups and that they are in solid rather than liquid form. In addition, they will preferably have a molecular weight per epoxide of between 100 and approximately 2000, preferably between 110 and 500. As examples of epoxy resins, mention may in particular be made of polyethers of glycidyl of polyhydric phenols which are derived from an epihalohydrin such as for example epichlorohydrin, and a polyhydric phenol. Examples of such phenols include resorcinol, hydroquinone, bis (4-hydroxyphenyl) -2,2 propane or bisphenol A, 4,4'dihydroxybenzophenone, bis- \ (4-hydroxy-phenyl) -1, 1-ethane, bis (4-hydroxy-phenyl) -1,1-isobutane, bis (4-hydroxy-phenyl) -2,2-butane, bis (2-dihydroxynaphtyl) methane, phloroglucinol, and bis (4-hydroxyphenyl) sulfone. Mention may also be made of other polyhydric phenols such as the novolak resins containing more phenols or substituted phenols, with parts linked by methylene bridges, as well as phenolic compounds //. - 6 - halogens, for example bromine and chlorine.

Epoxy resins which consist of polyether glycidyl of polyhydric alcohols can be prepared by reacting a polyhydric alcohol with an epihalohydrin in the presence of an acid catalyst such as boron trifluoride, and subsequently treating the resulting product with an alkaline agent. dehydrohalogenation. Among the polyhydric alcohols which can be used during the preparation of these polyepoxides, mention may be made of glycerin; ethylene. glycol, propylene glycol, diethylene glycol, hexane diol, hexanetriol, trimethylolpropane, trimethylolethane, pentaerythritol and the like.

As other epoxy resins, mention may be made of glycidyl esters of polycarboxylic acids which are derived from an epihalohydrin and a polycarboxylic acid according to the methods described in US Patents 3,859,314 and 3,576,827 introduced here for references. Examples of polycarboxylic acids that may be mentioned include phthalic acid or its anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic anhydride, adipic acid, dimerized fatty acids , dibasic acids prepared from unsaturated fatty acids and acilic acids and the like. However, preferably glycidyl polyether bisphenol A is used.

The epoxy resins used in the present invention can also result from the mixture of several epoxy resins or from the mixture of an epoxy resin with a reactive diluent. As an example of reactive diluent, there may be mentioned the glycidyl ester of undecanoïgue acid (sold under the name of Cardura E10 by Shell).

With the epoxy resin, a conventional hardener of the epoxy resins is mixed. As curing agent for epoxy resins, mention may in particular be made of amino compounds, such as diamines, triamines and more generally alkylene polyamines.

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It is also possible to cure the epoxy resin by forming an adduct in situ resulting from the reaction of an amino compound and the epoxy resin.

In place of the amino compounds, polyamides can also be used as hardener. Generally, these products come from the reaction of a diamine with a dicarboxylic acid which is itself obtained by dimerization of fatty acids. The condensation of the dimerized fatty acid with an excess of diamine gives compounds of the polyaminoamide type which are particularly advantageous as curing agents for epoxy resins, titre As concrete examples, mention may be made of the polyaminoamides resulting from fatty acids having from 12 to 22 carbon atoms which are reacted with an alkylene polyamine, in particular the alkylenediamines, the alkyl group having from 1 to 6 carbon atoms.

In particular, mention may be made of Epilinks such as 350, 350M, 360, 370 (products marketed by AKZO) and Versamide 115, 115X, 125 and 140 (products marketed by General Mills).

As a rule, it is desirable to put an excess of polyaminoamide product over the epoxy resin. Most often, 100 to 150 parts of hardening compounds are used per 100 parts of epoxy resin.

The composite panel of the present invention also comprises a protective layer of mortar constituted by cement chosen from Portland cements, metallurgical cements or pozzolan cements, a surfactant and fibrillary films of polyolefins.

One of the advantages of the present invention lies in the fact that a wide range of cements can be used, which was far from being the case in the previous processes.

Indeed, Portland cements can be used which result from a mixture of limestone and clay and whose * general composition includes: * ’. . - 8 - 18 to 27% of S1O2 4 to 11% of A ^ O ^ 2 to. 5% Fe ^ O ^ 48 to 67% CaO 2% MgO 1.2% S03 0 to 2% d1 alkalis

Among the Portland cement-based cements, it is possible in particular to use types P30, P40 and P50 which form part of the composition given above.

It is also possible to use compensated shrinkage cements such as Portland cements of type K, M and S: - Type K: results from a mixture of Portland cement, anhydrous calcium sulfoaluminate (4 CaO. SA ^ O ^. SO ^) of calcium sulphate and lime.

- Type M: results from a mixture of Portland cement, calcium aluminate cement and calcium sulphate.

- Type S: results from the mixture of Portland cement with a significant quantity of tricalcium aluminate and modified by an excess of sodium sulfate.

Metallurgical cements can also be used, such as in particular slag cements including blast furnace cements. We know that slags are made up of the same elements as cements, but with a different lime content. Dairies therefore generally contain from 20 to 36% of S1O2 from 7 to 16% of A ^ O ^ from 0.7 to 2.5% of Fe2 ° 3

38 to 66% CaO

0.5 to 2.5% MgO

1.5 to 2.7% S

In the present invention, use is preferably made of a blast furnace cement which is constituted by 60 to 85% of Portland cement and by 40 to 15% of slag.

You can also use the pozzolans for, '/. - 9 - form the mortar layer. Pozzolans are siliceous materials which are able to combine directly with lime to form a mixture which can harden like a cement. Typical pozzolan cements can contain from 5 to 20% of pozzolan, and from 95 to 80% of Portland cement, the compositions of which have been described above.

The mortar composition also contains binder sand, in an amount such that the sand / cement ratio is between about 2.75: 1 and about 3: 1.

In the implementation of cements, the amount of water used is also very important, to give compositions of optimum usability. Generally, at least 25% by weight of water is used, relative to the weight of cement, and preferably an amount between 35 and 65% by weight.

The mortar composition also contains surfactants. Nonionic, anionic surfactants or mixtures thereof can be used.

As examples of nonionic surfactants, there may be mentioned: fatty acid esters, such as glycerol monostearate, diethylene glycol laurate, propylene glycol monostearate, sorbitol monolaurate and pentaerythritol monostearate, acid derivatives of ethylene oxide products, such as the reaction product of six moles of ethylene oxide with one mole of oleic acid, condensation products of ethylene oxide with alcohols, such as stearyl alcohol, and condensation products of ethylene oxide with phenols, naphthols and alkyl phenols such as di-t-butylphenoxy-nonacoxyethylene-ethanol. The condensation products of ethylene oxide with alkyl phenols are preferred.

Examples of anionic surfactants include: alkyl aryl sulfonates, such as sodium dodecylbenzene sulfonate; sulphate derivatives of higher fatty alcohols (that is to say alcohols of at least 9 carbon atoms and ordinarily of at most 17 carbon atoms), such as sodium lauryl sulphate; sulfonated animal and vegetable oils, such as sulfonated fish and castor oils, sulfonated acyclic hydrocarbons, etc.

• At least 15% of the component formed by anionic surfactant of the cement additive of the present invention should be constituted by a higher alkyl sodium sulfate, for example sodium lauryl sulfate, and the component formed by the anionic surfactant: which should preferably consist of a mixture of an alkyl aryl sulfonate and a sodium alkyl sulfate.

In the present invention, however, it is preferred to use the sodium salt of naphthalene sulfonate.

Surfactants are generally used in an amount of 0.1 to 5% by weight relative to the weight of cement, but it is preferable to use an amount between 0.5 and 2% by weight.

To prevent the cement mortars from cracking, which considerably reduces their potential resistance, it is preferable to reinforce them with reinforcing agents.

The Applicants have now found that by using fibrillar polyolefin fibers, not only is the desired reinforcement obtained, but also unexpectedly better adhesion is obtained between the insulating layer and the cementitious layer.

It is preferred to use polyolefin films which have been fibrillated beforehand, for example according to the method described in Belgian patent 856,389 (equivalent to US patents 4,297,409 and GB 1,582,945), so that they form networks continuous open like nets during the preparation of the mortar. Polypropylene fibrillar films preferably having a length of between 1.2 and 3.6 cm, more particularly equal to approximately 2.4 cm, are used, and in a proportion of 0.02 to 0.4% by weight based on the weight • · - 11 - i, total mortar. A content exceeding 0.4% by weight gives a composition which is more difficult to mix, since the saturation threshold is exceeded, which leads to a coating with lower resistance.

The mortar compositions are prepared by simply adding the additives necessary to obtain a mixture having the desired workability and consistency.

It has been found that the composite panels obtained from the mortar compositions of the present invention thus modified have better resistance to freeze-thaw cycles, to thermal cycles, and a better flexural modulus. In addition, it has been found that with the presence of fibrillary polyolefin films, the formation of microcracks is significantly reduced.

The composite panel of the invention is produced using an extruded expanded polystyrene panel. The usual panels have a thickness varying between 3 and 12 cm, a width usually between 30 and 70 cm and a length most often between 1 m and 2.5 m. It is understood that instead of panels, it is possible to use slabs which result from the cutting of the panels described above.

One of the surfaces of the panel is covered with a layer of an epoxy resin containing a usual hardener for epoxy resin, most often at a rate of 100 to 120 parts per 100 parts of resin.

The thickness of the resin layer does not exceed 5 mm, and generally not 1 mm. In particular, it is most often between 0.05 and 0.5 mm.

A layer of mortar is poured over the surface covered by the epoxy resin. In general, the thickness of the mortar layer is between 1 and 5 cm.

According to an embodiment of the present invention, the cement mortar is prepared by mixing a blast furnace cement containing about 35% slag with a '. - 12 - sufficient amount of water to have a water / cement ratio of 0.3 to 0.7, an amount of sand binding in an amount ensuring a sand / cement ratio of between approximately 2.75: 1 and 3: 1 ; to this we add about 0.5 to 2% by weight of sodium salt of naphthalene sulfonate as surfactant and finally we mix from 0.04 to 0.4% by weight relative to the mortar of fibrillar polypropylene films . The panels thus formed are then cured under ambient temperature conditions.

The following examples are given to illustrate: the present invention but without limiting its scope.

Example 1

Several extruded polystyrene panels with a length of 2.5 m, a width of 0.6 m and a thickness of 4 cm were used.

On a surface of these panels, a layer of Epikote 213 epoxy resin (based on diglycidyl ether of bisphenol A) was applied, to which the same quantity of a polyaminoamide was previously mixed as hardener. The thickness of the adhesion layer was approximately 0.1 mm.

On the other hand, a mortar comprising 500 kg of blast furnace cement containing 35% slag was prepared, so as to form a cement whose composition (in% by weight) is:

Si02 29-35 Fe2 ° 3 0.2-1

CaO 38-46 MgO 4-12 A1203 10-16 S 0.6 - 1.9 1560 kg of Meuse sand, and 125 1 of water.

Sodium salt of naphthalene sulfonate was mixed with this composition in an amount of 1% on the weight of the cement, and fibrillar polypropylene films were incorporated in an amount of 0.04% relative to the weight of the mortar.

The mortar was poured over the surface of the panel already covered with epoxy resin.

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The mortar layer was then dried, leaving it at room temperature for 28 days.

The composite panel thus formed was subjected to a thermal cycle comprising an exposure for 1 hour to UV and infrared radiation up to a temperature of 80 ° C., then half an hour of rain and finally half an hour of rest .

No deformation or cracking was found after 75 cycles.

- For comparison, an extruded expanded polystyrene panel was covered with the same mortar, but omitting the layer of epoxy resin. It was found that there was practically no grip.

For comparison, a panel of the same type was covered with a mortar comprising a latex of a styrene-butadiene copolymer (proportion 30/70). The composite panel was subjected to the same thermal cycle as that described above, and detachment was found after 14 cycles.

Example 2

Extruded expanded polystyrene panels were used such as those described in Example 1.

On a surface of these panels, a layer of Epikote 213 epoxy resin (based on diglycidyl ether of bisphenol A) was applied to which the same quantity of a polyaminoamide was previously mixed as a hardener. The thickness of the adhesion layer was approximately 0.4 mm.

On the other hand, a mortar comprising 500 kg of Portland P30 cement containing 10% pozzolan was prepared to „* form a cement whose composition in percent by weight is: SiC> 2 * 25.6 to 27.2 ^ e2 ^ 3: 2.9 to 3.1

CaO: 63.2 to 64.0 MgO: 2.8 to 3.0 A1203: 6.3 to 7.7 S03: 2.4 to 3.0 remainder: 1.9 to 2.5 1,560 kg of sand Meuse and 125 1 of water.

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Sodium salt of naphthalene sulfonate was mixed with this composition at a rate of 1% on the weight of cement and different quantities of fibrillary polypropylene films, namely 0.1% in test 2A and 0, were incorporated. .07% in test 2B.

The mortar was poured over the surface of the panel already covered with epoxy resin.

The mortar layer was then dried, leaving it at room temperature for 28 days.

The composite panels thus formed were subjected to a thermal cycle comprising an exposure for 1 hour to UV and infrared radiation up to a temperature of 80 ° C, then half an hour of rain and finally half an hour of rest.

The results are shown in Table 1 below.

TABLE 1

Test 2A: no cracking after 75 cycles Test 2B: no cracking after 75 cycles

Example 3

Extruded expanded polystyrene panels were used like those described in Example 1.

A layer of Epikote 213 epoxy resin was applied to a surface of these panels to which the same amount of polyaminoamide was previously mixed as a hardener. The thickness of the adhesion layer was 0.1 mm.

The same cement mortar was prepared as in Example 1, but three compositions were made having different contents of fibrillary polypropylene films.

Composition A contained 0.44% by weight based on the mortar.

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Composition B contained 0.88% and Composition C contained 1.32%.

After having spread the various mortars on the surface of the panels already covered by the epoxy resin, they were left to dry for 28 days at room temperature.

The flexural modulus of the various composite panels was determined (Table 2).

TABLE 2

Panels Panels Panels

with composition A with composition B with composition C

31,000 kN / mm2 27,000 kN / mm2 '‘23 .000 kN / mm2

Claims (15)

1. Composite construction panel comprising a main body made of an expanded material with generally smooth skin and closed cells and a protective mortar coating adhering to at least one surface of the main body of expanded material by means of a layer of an organic resin, characterized in that the mortar coating comprises a cement chosen from Portland cements, metallurgical cements and pozzolan cements, a surfactant in an amount of 0.1 to 5% by weight based on cement, and fibrillar polyolefin films with a 0.02 to 0.4% by weight basis based on the mortar, and in that the organic resin layer comprises an epoxy resin and an epoxy resin hardener , the thickness of the adhesion layer not exceeding 1 mm. 2. Construction panel according to claim 1, characterized in that the thickness of the adhesion layer is between 0.05 and 0.5 mm. 3. Construction panel according to any one of claims 1 or 2, characterized in that the expanded material is chosen from expanded polystyrene molded or ex-extruded, the foams obtained from styrene-acrylonitrile copolymer or copolymer methyl styrene-methacrylate, expanded polyvinyl chloride, expanded polyurethane, expanded polyethylene, phenolic foams, ceramic foams and glass foams. 4. Construction panel according to claim 3, characterized in that the expanded material is extruded polystyrene. "'- 17 - 5. Construction panel according to any one of claims 1 to 4, characterized in that the metallurgical cement is a blast furnace cement comprising from 15 to 40% slag and 85 to 60% Portland cement. 6} Construction panel according to any one of claims 1 to 5 ,. characterized in that the surfactant of the mortar composition is chosen from nonionic surfactants, anionic surfactants 1 or their mixtures. 7. Construction panel according to claim 6, characterized in that the surfactant is the sodium salt of naphthalene sulfonate. 8. Construction panel according to any one of claims 6 or 7, characterized in that the surfactant is present in the mortar at a rate of 0.5 to 2% by weight based on the cement present in the mortar . 9. Panel according to any one of claims 1 to 8, characterized in that the polyolefine fibrillar films present in the mortar are fibrillar films of polypropylene. 10. Construction panel according to any one of claims 1 to 9 characterized in that the adhesion layer comprises (1) an epoxy resin, chosen from saturated, unsaturated, aliphatic, cycloaliphatic or heterocyclic epoxy resins, and preferably a bisphenol A gly-cidyle ether, and (2) an epoxy resin hardener, preferably a polyaminoamide. 11. Construction panel according to claim 10, characterized in that the hardener is introduced at the rate of ψ> * - 18 - • * 100 to 150 parts per 100 parts of epoxy resin. 12. Construction panel according to any one of claims 10 or 11, characterized in that the epoxy resin is the diglycidyl ether of bisphenol A and the hardener is a polyaminoamide. -13) A method for promoting the adhesion of a mortar composition to the surface of an expanded material to form 1 a building panel according to any one of claims 1 to 12, this method being characterized in that it includes the steps which consist in: - applying to the surface of the expanded material a layer of an epoxy resin containing a usual hardener of epoxy resins; - apply a layer of mortar to the surface of the layer of epoxy resin; - let the mortar harden. 14. Method according to claim 13, characterized in that an expanded material is chosen chosen from expanded or extruded polystyrene, the foams obtained from styrene-acrylonitrile copolymer or from styrene-methyl methacrylate copolymer, polyvinyl chloride expanded, expanded polyurethane, expanded polyethylene, phenolic foams, ceramic foams and glass foams. 15. The method of claim 14, characterized in that the expanded material that is used is extruded polystyrene. 1 Method according to claim 13, characterized in that the layer of mortar comprises a cement chosen from Portland cements, metallurgical cements and <. · *. -19- t pozzolans, a surfactant chosen from anionic and nonionic surfactants and used at a rate of 0.1 to 5% by weight based on the weight of the cement and of polyolefin fibrillary films at a rate of 0.02 to 0.4% by weight based on the weight of the mortar. 17. Method according to claim 16, characterized in that the fibrillar films of polyolefin are fibrillar films of polypropylene. 18. Method according to any one of claims 13 to 17 characterized in that the epoxy resin is the diglycidyl ether of bisphenol A and that the hardener is a poly-aminoamide. Brussels, the Par Pon of Societies known as C.B.R. BETON S.A. and SYNFINA S.A.