EP4426773A1

EP4426773A1 - Expanded polystyrene with a latex for floor applications

Info

Publication number: EP4426773A1
Application number: EP22802251.3A
Authority: EP
Inventors: Christof STAMPER
Original assignee: Isostar BV
Current assignee: Isostar BV
Priority date: 2021-11-05
Filing date: 2022-10-17
Publication date: 2024-09-11
Also published as: BE1029901B1; WO2023079390A1; BE1029901A1

Abstract

The present invention relates to a kit suitable for forming a recyclable insulating floor layer, the kit comprising: a plurality of expanded polystyrene (EPS) granules with a density of 10-35 kg/m3 and a moisture absorption by immersion of maximum 5%; and a binding agent, wherein the binding agent comprises a polymer-in-water emulsion. The invention further relates to a kit comprising recycled material, the kit suitable for forming a re-recyclable insulating floor layer, the kit comprising: a plurality of recycled flakes comprising cut up expanded polystyrene (EPS) granules, bonded by means of a first binding agent; and a second binding agent, wherein the binding agent comprises a polymer-in-water emulsion.

Description

EXPANDED POLYSTYRENE WITH A LATEX FOR FLOOR APPLICATIONS

TECHNICAL FIELD

The invention relates to insulating and lightweight floor elements. More specifically, the invention relates to a kit suitable for simply applying a thermal floor insulation, a method for applying a light floor insulation and said light floor insulation.

PRIOR ART

Cellular concrete or aerated concrete is a type of concrete that is characterized by its low density and strong insulating capacity. By adding a gas-forming additive, a porous and insulating material is created. The air bubbles formed are not in communication with each other. After the mass is taken out of the mold, it is cut into the desired product type: blocks, lintels, reinforced plates.

Expanded polystyrene (EPS) has been used for many purposes for over 50 years. It was originally intended as an insulation material, which is still its largest application, in addition to packaging. EPS products are manufactured in the form of blocks, plates or molded parts. The blocks can be cut into plates and many arbitrary molded parts. EPS building products are supplied pre-formed, such as EPS cavity boards and high- quality composite products such as sandwich panels or laminated roof insulation. US Patent US 5,916,681 teaches the use of EPS as loose insulation, in a sandwich panel, as a preformed board and in combination with cement. US 4,1234,242 describes a loose insulation consisting of fibers and a granular material.

Concrete is heavy and has a low thermal insulation, which is disadvantageous when insulating several floors. Furthermore, EPS is usually supplied either loose or preformed.

Relative to other insulating layers, [the present invention] aims at an improvement within the insulating layers for floors; in particular in the field of:

Recyclability: a major problem with current insulation materials is the limited possibility of recycling or reuse;

Improved thermal insulation;

Improved compressive strength;

Reduced ecological impact; and Simple method for installing such floor layers.

BE 1 026 242 describes an insulating floor layer, kit and method for its manufacture. An unforeseen disadvantage of the combination of water-based polymer emulsion and a multitude of EPS granules is that this water has to escape from the kit in order to obtain good curing of the floor layer. This is particularly a problem with thicker floor layers with only one free surface. Poor curing is pernicious for the insulating effect of the floor layer. While this can be remedied with layer-by-layer application and curing of the floor layer, this method takes significantly more time and labor. using EPS granules in combination with a water-based polymer emulsion

SUMMARY OF THE INVENTION

The invention relates to a kit suitable for forming an insulating floor layer according to claim 1. The inventors have surprisingly discovered that a moisture absorption by immersion of the EPS granules of up to 5% is essential for producing a thermally good insulating floor layer.

On the one hand, a low moisture absorption is necessary to allow recycling of a used floor layer into cut flakes that can be used again for a similar floor layer. All the more if washing the flakes is desired.

In addition, the exclusion of moisture absorption by the EPS granules is advantageous for obtaining a better thermal insulation. The thermal insulation can always be improved by providing a thicker insulating layer. Thicker insulation layers, however, are more difficult to dry and harden. For example, water from a polymer- in-water binding emulsion can remain in the insulating layer. This absorbed water significantly reduces the thermal insulation, which can partly negate the advantage of a thicker insulating layer. In addition, water can also enter the insulating layer via other routes, such as rising groundwater in the event of a faulty water barrier.

A preferred kit is described in claim 2. Such kits give rise to increased thermal insulation and compressive strength compared to kits with a lower weight percentage of EPS granules. In a second aspect, the invention relates to a method for applying an insulating floor layer to a substrate, comprising (a) mixing a plurality of expanded polystyrene granules with a binding agent resulting in a substantially liquid insulating material according to a kit according to the first aspect, (b) distributing the liquid insulating material on the substrate, and (c) curing the liquid insulating material to form an insulating floor layer.

This is advantageous over construction boards and other pre-formed building elements, as the kit can be used in any form of any size. For example, the substrate does not have to be flat, since the kit is form-free. The kit is also easy to transport and store in various forms, regardless of the shape of the intended insulating floor layer.

This method is advantageous over known insulating foams as it is simpler and cleaner. Due to a limited reaction, fewer harmful gases are released, less heat is formed as a result of exothermic reactions and the volume of the insulation material remains more or less constant. Further, the steps in the second aspect can be performed in the simplest order. For example, large quantities of granules and binding agent can be easily mixed in industrial concrete mixing plants. Small amounts of binding agent can be easily applied to the EPS on the substrate. This way no further material is befouled. Finally, it is possible to simultaneously provide the EPS granules with binding agent and apply the resulting slurry to the substrate. This can be done, for example, using a blower or screw suitable for EPS granules, provided with binding agent at the end. Finally, this is beneficial for leveling a floor, and appropriate insulation around pipes and other facilities in the floor of a building.

Another preferred kit is described in claim 3. Kits with only EPS granules and binding agent, especially in this ratio, can be processed into a floor layer. This floor layer can later be cut into flakes; which flakes can be reprocessed into an insulating floor layer in combination with a binding agent. In a third aspect, the invention relates to a kit consisting of recycled flakes, suitable for a re-recyclable floor layer according to claims 12-15. Excluding further components prevents undesired stacking or forced processing of these further components. In particular, the addition of cement-based products is strongly discouraged, as these crumble strongly during the recycling process and thus greatly reduce the quality of the recycled product.

In a fourth aspect, the invention relates to a method for recycling a floor layer. In a further aspect, the invention relates to the insulating layer formed with a kit according to the first aspect or by means of the method according to the second aspect.

This insulating layer has better thermal insulation and a lower specific gravity than aerated concrete and concrete with EPS granules. Furthermore, this insulating layer has a better compressive strength than polyurethane foams. Furthermore, this insulating layer is recyclable, unlike cement and foam-based products.

DETAILED DESCRIPTION

The invention relates to a kit suitable for forming a light, insulating floor layer. The invention furthermore relates to a method for providing an insulating floor layer. Finally, the invention relates to a light insulating floor layer.

Unless otherwise defined, all terms used in the description of the invention, including technical and scientific terms, have the meaning as commonly understood by a person skilled in the art to which the invention pertains. For a better understanding of the description of the invention, the following terms are explained explicitly.

In this document, 'a' and 'the' refer to both the singular and the plural, unless the context presupposes otherwise. For example, 'a segment' means one or more segments.

The terms "comprise", "comprising", "consist of", "consisting of", "provided with", "have", "having", "include", "including", "contain", "containing" are synonyms and are inclusive or open terms that indicate the presence of what follows, and which do not exclude or prevent the presence of other components, characteristics, elements, members, steps, as known from or disclosed in the prior art.

"Dispersion polymerization" is a type of precipitation polymerization, which means that the selected solvent is both the reaction medium and is a good solvent for the monomer and initiator but is not a good solvent for the polymer. As the polymerization reaction proceeds, particles of polymer form, forming a non- homogeneous solution. In dispersion polymerization, these particles are the site of polymerization. Quoting numerical ranges by endpoints includes all integers, fractions and/or real numbers between the endpoints, these endpoints included.

In a first aspect, the invention relates to a kit suitable for forming a recyclable insulating floor layer, the kit comprising:

A. a plurality of expanded polystyrene (EPS) granules with a density of 10-35 kg/m³ and a moisture absorption by immersion of up to 5%; and

B. a binding agent, wherein the binding agent comprises a polymer-in- water emulsion.

A problem with water-based emulsions is that water can be absorbed by EPS granules. EPS granules that absorb water show a significantly lower thermal insulation. This is a problem especially with thicker insulation layers, where water escapes less easily. The inventors have discovered that coating the plurality of EPS granules allows to obtain EPS granules with a moisture absorption upon immersion of less than 5%. As a result, the EPS granules with low moisture absorption show an improved insulation value in the final product. The improvement also increases as the insulating layer increases in thickness.

In a preferred embodiment, the moisture absorption upon immersion of the plurality of EPS granules is at most 4.5%, more preferably, the moisture absorption upon immersion of the plurality of EPS granules is at most 4.0%, more preferably, the moisture absorption upon immersion of the plurality EPS granules is at most 3.5%, more preferably, the moisture absorption upon immersion of the plurality of EPS granules is at most 3.0%, more preferably, the moisture absorption upon immersion of the plurality of EPS granules is at most 2.5%, more preferably, the moisture absorption upon immersion of the plurality of EPS granules is at most 2.0%, more preferably, the moisture absorption upon immersion of the plurality of EPS granules is at most 1.5%, more preferably, the moisture absorption upon immersion of the plurality of EPS granules is at most 1.0%, more preferably, the moisture absorption upon immersion of the plurality of EPS granules is 0.5% at most. The moisture absorption upon immersion is measured by immersion in water for 120 hours at a temperature of 23°C. The moisture absorption is then calculated as the difference in weight of the EPS granules before and after immersion, divided by the weight of the EPS granules before immersion, expressed in percent. In a preferred embodiment, the moisture absorption of the EPS granules is reduced by adding a base to the steam used to expand the polystyrene granules. In a preferred embodiment, 50 to 200 ml of aqueous base is added per m³ of water; wherein the aqueous base has a pH between 10 and 14, preferably a pH between 12 and 13. More preferably, the base is selected from the list of: sodium bisulfite, sodium hydroxide, sodium phosphonate or a mixture thereof. The inventors have discovered that adding an alkalizing agent to the steam boiler significantly reduces the moisture absorption by immersion of the obtained EPS granules.

The plurality of expanded polystyrene (EPS) granules preferably have a density of

10-35 kg/m³. In a preferred embodiment, the EPS granules have a density between

15 and 35 kg/m³, more preferably the EPS granules have a density between 16 and

34 kg/m³, more preferably the EPS granules have a density between 17 and 33 kg/m³, more preferably the EPS granules have a density between 18 and 32 kg/m³, more preferably the EPS granules have a density between 18 and 31 kg/m³, more preferably the EPS granules have a density between 18 and 30 kg/m³, more preferably the EPS granules have a density between 18 and 29 kg/m³, more preferably the EPS granules have a density between 18 and 28 kg/m³, more preferably the EPS granules have a density between 18 and 27 kg/m³, more preferably the EPS granules have a density between 18 and 26 kg/m³, more preferably the EPS granules have a density between 18 and 25 kg/m³, more preferably the EPS granules have a density between 19 and 24 kg/m³, more preferably the EPS granules have a density between 19 and 23 kg/m³, more preferably the EPS granules have a density between 19 and 22 kg/m³, more preferably the EPS granules have a density between 20 and 22 kg/m³, most preferably the EPS have granules have a density between 20 and 21 kg/m³. With EPS granules of this preferred density, both a high insulation value and a high compressive strength are obtained. At higher and lower densities, the product's insulation value and compressive strength decrease.

Preferably, the plurality of expanded polystyrene (EPS) granules are fully preexpanded. In a preferred embodiment, the EPS granules have a diameter between 1 and 8 mm. Granules smaller than 1 mm gave rise to too much dust. Granules larger than 6 mm had a negative effect on the insulating effect of the final product. Preferably, the diameter of the EPS granules is between 2 and 6 mm, even more preferably between 3 and 6 mm, most preferably between 4 and 6 mm. EPS granules with a diameter between 4 and 6 mm gave rise to the highest insulation value for the final material. Granules smaller than 4 mm lead to a long drying period and a reduced compressive strength of the final insulating layer.

In a preferred embodiment, the EPS granules are "gray." Gray EPS is known to those skilled in the art and consists of EPS granules containing graphite or carbon. These are produced by adding graphite or carbon when forming unexpanded EPS beads. Grey EPS granules have better insulating properties. These are passed on to the final insulation material.

In a further preferred embodiment the mass fraction of the EPS granules in the kit is between 0.40 to 0.80, preferably between 0.61 to 0.75, even more preferably between 0.62 to 0.75, even more preferably between 0.63 to 0.75, even more preferably between 0.64 to 0.75, even more preferably between 0.65 to 0.75, even more preferably between 0.66 to 0.75, even more preferably between 0.67 to 0.74, even more preferably between 0.68 to 0.73.

In a preferred embodiment, the kit consists of the following components:

A. the expanded polystyrene (EPS) granules in a ratio of 61-75 wt.% to the weight of the complete kit; and

B. the binding agent in a ratio of 25-39 wt.% to the weight of the complete kit.

The inventors discovered that the higher weight percentages of EPS granules give rise to an improved insulation (lower lambda value) in both the initial product but in particular in the recyclate that can be produced from this initial product. In this way a more favorable, higher quality recycled material is obtained.

The binding agent is a polymer-in-water emulsion. The chain of this polymer consists mainly of carbon, oxygen, nitrogen, silicon such as polysiloxane. Preferably, the binding agent is a latex. "Latex" in this text is defined as a stable dispersion or emulsion of polymer particles in a solvent. This solvent is water. Even more preferably, the binding agent is a polymer-based binder. A binding agent based on dispersion polymerization will usually give rise to a latex, being a dispersion of polymer particles in a solvent. In a preferred embodiment, the polymer is selected from the group consisting of: polystyrene (PS), polystyrene-butadiene copolymer, polybutadiene rubber (BR), isoprene rubber (IR), chloroprene rubber (CR), nitrile rubber (NBR), ethylene-propylene-diene-monomer (EPDM), isobutylene isoprene rubber (HR), polyisobutylene (PIB), silicone rubber (VMQ), fluorine rubber (FKM), ethyl vinyl acetate rubber (EVA), chlorosulfonated polyethylene rubber (CMS), acrylate rubber (ACM) or polyurethane rubber (AU or EU). More preferably, the polymer is selected from the group of: polystyrene (PS), polystyrene-butadiene copolymer, polybutadiene rubber (BR), isoprene rubber (IR), ethylene-propylene- diene-monomer (EPDM), isobutylene isoprene rubber (HR), polyisobutylene (PIB) or ethyl vinyl acetate rubber (EVA). Even more preferably, the polymer is selected from the group consisting of: polybutadiene rubber (BR), isoprene rubber (IR), ethylene- propylene-diene-monomer (EPDM) and polystyrene-butadiene copolymer. Most preferably, the polymer is polystyrene-butadiene copolymer. Polystyrene-butadiene copolymer gives good adhesion to polystyrene surfaces. This is particularly important to prevent micro-cracks and associated thermal bridges. The inventors have surprisingly discovered that the use of a polystyrene-butadiene-based binding agent allows to obtain lambda values lower than 0.030 W/mK. Furthermore, polystyrene- butadiene copolymer has very good mechanical properties, resulting in a floor layer with high compressive strength. The use of a largely polystyrene based insulating layer for both beads and binding agent allows better recycling. The absence of heteroatoms, in particular chlorine and fluorine, but to a lesser extent nitrogen, phosphorous and silicon also contributes to this.

Even more preferably, the binding agent is based on dispersion polymerization or copolymerization, preferably copolymerization. In a further preferred embodiment, the solvent used for dispersion polymerization or copolymerization may be water. This is environmentally friendly.

In a preferred embodiment, said binding agent, being a latex or whether or not based on dispersion polymerization, has a dry substance content between 20 and 70%, preferably between 25 and 65%, even more preferably between 25 and 60%, even more preferably between 30 and 50%, even more preferably between 35 and 45%.

The use of a binding agent contained in a solvent allows the granules to be completely mixed with the binding agent, wherein the surface of the EPS granules is completely covered thanks to the solvent. This improves the bond between the EPS granules and the polymer matrix. However, the solvent does not remain in the final product in large quantities but leaves the insulation material almost completely during curing.

Preferably, the latex is formed by dispersion polymerization, which is stopped at a high degree of polymerization. In a further preferred embodiment, a latex based on dispersion polymerization is capable of further polymerization after mixing with the EPS granules. This creates a strong, three-dimensional matrix. Still, the polymerization during this last step can be very small; the vast majority of polymer chains are formed in the production of the latex based on dispersion polymerization. Thus, the properties of both the polymer and the latex can be controlled without being dependent on the user. This is advantageous for use as a kit, for example for do-it-yourselfers.

A latex can be supplied ready for use in liquid form. This is advantageous over known polymer foams, such as polyurethane, wherein exothermic reactions are necessary to form the polymer. The polymerization reactions usually also lead to a significant volume increase in foaming. This makes it more difficult to apply said materials to form a floor. Due to this on-site reaction, the microscopic and macroscopic properties of these insulating foams are less consistent.

The degree of polymerization, branching and end functionalities can be better controlled. This is because these properties change only very slightly, as the majority of the polymerization takes place during the production of the latex, and not when the latex is used as a binding agent. However, control over the degree of crosslinking is very important.

The curing of insulating foams is accompanied by volatile, possibly toxic and environmentally harmful gases. The curing of a water-based latex polymer involves evaporation of water and little reaction. On the one hand, this is more environmentally friendly and, on the other hand, healthier for the skilled person who applies the insulation.

In a further preferred embodiment, the latex has a Brookfield viscosity of 1 to 10000 mPa.s, preferably 5 to 5000 mPa.s, even more preferably 1 to 1000 mPa.s, even more preferably 50 to 500 mPa.s, most preferably 50 to 300 mPa.s. This Brookfield viscosity is the viscosity measured with a Brookfield viscometer with spindle 1, at 50 revolutions per minute at a temperature of 20°C.

These polymers insulate thermally better than cement. As a result, the kit also has a better thermal insulation than aerated concrete based on similar EPS granules. The preferred polymers result in a good balance of compressive strength, weight and insulation. In a further preferred embodiment, the mass fraction of the binding agent in the kit is between 0.10 and 0.60, preferably between 0.20 and 0.50, even more preferably 0.22 to 0.45, even more preferably 0.25 to 0.40, even more preferably 0.25 to 0.39, even more preferably 0.25 to 0.35, even more preferably 0.26 to 0.34, most preferably between 0.27 and 0.33. dlO is the particle size where 10 wt.% of the expanded polystyrene granules have a smaller particle size and 90 wt.% of the expanded polystyrene granules have a larger particle size. d90 is the particle size where 90 wt.% of the expanded polystyrene granules have a smaller particle size and 10 wt.% of the expanded polystyrene granules have a larger particle size. The particle size is preferably determined by laser diffraction; wherein the mass based particle size distribution is obtained by multiplying the volume of the particles by the average density of the EPS granules. In a preferred embodiment, the EPS granules have a narrow particle size distribution. More preferably, dgo - dio, i.e. particle size distribution of the 80 wt.% EPS granules with the intermediate particle sizes, is less than 3.0 mm, more preferably less than 2.5 mm, more preferably less than 2.0 mm, more preferably less than 1.5 mm, more preferably less than 1.2 mm, more preferably less than 1.0 mm, more preferably less than 0.9 mm, more preferably less than 0.8 mm, more preferably less than 0.7 mm, more preferably less than 0.6 mm, more preferably less than 0.5 mm, more preferably less than 0.4 mm, more preferably less than 0.3 mm, more preferably less than 0.2 mm, most preferably less than 0.1 mm. Such narrow particle size distributions are advantageous on the one hand for laying the floor layer, in particular for covering all granules with sufficient binding agent and for leveling the obtained floor layer, for obtaining an insulating layer with constant and predictable insulation values and pressure values, and for optimal recycling of the floor layer into flakes. For example, with a narrow particle size distribution, the flake size can be better matched to the particle size of the EPS granules.

In a preferred embodiment, the kit comprises further additives. These can be added to the kit as an additional component on the one hand, or they can be included in the latex or the EPS granules on the other. Additives that improve polymer properties are known to those skilled in the art, for example flame retardants to improve the flammability of the final material, additives to improve chemical resistance and the like. The addition of materials with a high specific gravity, for example sand or quartz sand, to increase the sound insulation of the material are also known. In a further, preferred embodiment, the kit contains lithium silicate as an additive. This additive is known as a densifier and hardening agent in concrete. Surprisingly, lithium silicate was also found to have a very favorable effect on the compressive strength of a polymer matrix with EPS granules in between. In a further, preferred embodiment the mass fraction of lithium silicate is preferably between 0.005 and 0.15, even more preferably between 0.02 and 0.10, most preferably between 0.03 and 0.07.

In another preferred embodiment, the kit contains as few additives as possible, preferably no additives. In another preferred embodiment, the kit contains neither cement nor lithium silicate. In another preferred embodiment, the kit is free of foaming agents, in particular free of polysorbate, sodium lauryl ether sulfate, sodium coceth sulfate, sodium dodecyl sulfate, sodium bicarbonate and isocyanate, especially methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI). These additives, in particular cement, lithium silicate and foaming agents, cause recycling problems. This makes the recycling process more difficult to control and/or the insulation quality of the recycled material is significantly reduced.

In the most preferred embodiment, the kit consists of the following components:

This gives rise to a building material with compressive strength higher than 150 kPa, lambda value of 0.030-0.036 W/mK. This material is cheaper to install than polyurethane foams (PUR) and has a higher compressive strength than PUR. The material is lighter than cellular concrete and insulates better thermally.

In one embodiment, the kit further comprises reinforcement. This usually consists of metal, for example steel or a fiber material. This reinforcement serves to improve the structural properties of the matrix. In a preferred embodiment, polymer-based fibers are used. These adhere better in a polymer matrix and have a coefficient of expansion similar to the surrounding polymer matrix. This is advantageous to prevent delamination, the detachment of the reinforcement from the polymer matrix formed by the drying of the latex. In the second aspect, the invention relates to a method for applying an insulating floor layer to a substrate, comprising (a) applying a binding agent to at least a part of a surface of a plurality of expanded polystyrene (EPS) granules to form a slurry, (b) applying the slurry to the substrate, and (c) curing the slurry to form an insulating floor layer.

In one embodiment, applying binding agent to the surface of the EPS granules comprises blending or mixing the granules well with the binding agent. Mixing can be done in a variety of methods. Traditional concrete mixers or other methods of mechanical stirring or mixing will suffice. Furthermore, it is also possible to add liquid latex when applying the EPS granules to a floor, for example by means of a blower or feed screw. Finally, the mixing in can also be done by means of manual stirring, certainly for smaller quantities.

Applying EPS and/or binding agent to the substructure includes any method that provides EPS granules and binding agent at the location where the structural element is formed.

A slurry in this text is a mixture consisting of small, solid particles and a liquid. In bulk, the properties of a slurry resemble those of a viscous liquid. In this text, the small, solid particles are always EPS granules. A slurry is easy to apply as it is "formfree." By this it is meant that a slurry, much like a fluid such as a viscous liquid, will take the shape of the container in which it is contained. This is advantageous for applying an insulating layer along, for example, pipes, foundations and structural elements. This is very beneficial for renovations to a home, such as insulating an existing home. There, space is often limited within an existing frame, which must be worked around.

Furthermore, the form-free nature of the slurry ensures a close fit. This is advantageous for the insulating effect, since small gaps in the insulation give rise to thermal bridges. These thermal bridges are places where the insulation is interrupted and have a very detrimental effect on the complete insulation of a house.

Finally, the slurry is not blown in under pressure. The mixing of known polymer foams usually takes place simultaneously with their application, under pressure. Due to the high pressure, this work is usually not clean. For this, the house is usually covered with paper or plastics, or it has to be cleaned again. The slurry is preferably not applied under pressure. Combining and applying the elements of the kit can be done simultaneously, separately and sequentially. The EPS granules and latex can first be combined to fill a slurry, for example in known concrete mixers, after which this slurry is applied to a floor. This makes it easy to mix large amounts of EPS with binding agent. It is also possible to apply and mix in the EPS granules and the latex simultaneously on the floor. This way, EPS and latex are mixed in evenly. Furthermore, material that comes into contact with the latex is reduced. Finally, simultaneous mixing and application is the fastest method for many floors. It is also possible to first apply the EPS granules and then add the latex. Conversely, the latex can also be applied first, which promotes careful application along existing elements, after which EPS granules are added. It is important here that part of the latex is still more or less liquid before adding the EPS granules. It is also possible to work in layers, wherein a layer of EPS and latex is used for laying different layers of insulation material at different intervals. This can speed up the curing of the insulation. A combination of the above is also possible. For example, it may be advantageous to first provide the irregular structural elements with a layer of latex, so that thermal bridges are further avoided.

Preferably, steps (b) mixing the EPS granules and the binding agent and (c) applying the expanded polystyrene to a floor and (d) applying the binding agent to a floor can be performed simultaneously, separately or sequentially.

"Smoothing" or "leveling" is to make the floor layer flat, even or level. Leveling the slurry can be done in one or more steps. This can be done both before and after curing the slurry into an insulating layer. Preferably, a first leveling takes place before the slurry hardens. This can be done very quickly by spreading out the slurry briefly, for example with a rake. If a completely flat surface is desired, the slurry can be completely smoothed out before or during curing. Furthermore, the surface can be polished or sanded smooth after curing. This is easier than with concrete as the material is considerably less hard.

In a preferred embodiment, the EPS granules and the binding agent are mixed in for 30 seconds to 15 minutes, preferably for 30 seconds to 10 minutes, more preferably for 40 seconds to 5 minutes, more preferably for 50 seconds to 4 minutes.

Curing of the slurry takes 2 to 96 hours. This mainly depends on the thickness of the insulating layer, and to a lesser extent on the temperature and humidity. The curing of the slurry can simply be done in the air. In a preferred embodiment, the curing of the slurry is stimulated. This can be done by forced or natural convection above the floor surface, for example by properly ventilating the house. The use of absorbents can also accelerate curing.

In a preferred embodiment, the thickness of the insulating layer is between 1 and 60 cm, preferably between 2 and 50 cm, even more preferably between 3 and 50 cm, even more preferably between 4 and 50 cm. The upper limit of 50 cm is usually only used when building a floor, and of course not an intermediate floor, wherein both an insulating layer and a structurally supporting and leveling layer are desired. Above 60 cm lower lambda values are noted.

In a preferred embodiment, the EPS granules and binding agent are applied under low pressure. When applying under high pressure, it is often difficult to work cleanly. Masking and/or cleaning up leads to an extra cost.

The substructure is the surface on which the floor is installed. This can be a concrete layer, another floor layer, the ground, the foundation or a combination of the above. Furthermore, the substructure can also comprise structural elements, pipes and the like. The slurry can easily be applied on top of these elements, regardless of their structure.

In a third aspect, the invention relates to a kit comprising recycled material, the kit suitable for forming a re-recyclable insulating floor layer, the kit comprising:

A. a plurality of recycled flakes comprising cut up expanded polystyrene (EPS) granules, bonded by means of a first binding agent; and

B. a second binding agent, wherein the binding agent comprises a polymer-in-water emulsion.

In a preferred embodiment, the average particle size of the recycled flakes dso,rec is at least 0.5 mm larger, preferably at least 1.0 mm larger, more preferably at least 1.5 mm larger, more preferably at least 2.0 mm larger, most preferably at least 2.5 mm larger, than the average particle size dso, EPS of the bonded expanded polystyrene (EPS) granules.

In a preferred embodiment, the first and second binding agents are based on the same polymer or copolymer. Even more preferably, the first and second binding agents are based on the same polymer-in-water emulsion. In a preferred embodiment, the plurality of recycled flakes have a density comprised between 4 and 25 kg/m³, preferably between 15 and 25 kg/m³.

In one embodiment, an amount of (virgin) expanded polystyrene (EPS) granules can also be added to the recycled flakes. This addition will benefit the insulation value and compressive strength. Furthermore, a more manageable and predictable insulating layer is also obtained. However, the amount of recycled material is lower, and the amount of fresh material is higher, which means that this measure also has an ecological impact. It is therefore advantageous to produce the first floor layer and all recycled floor layers in such a way that the amount of new (virgin) material remains as low as possible; in order to keep the fraction of recycled material as high as possible and to optimize the ecological impact of the first product and the recyclates based on it.

In a fourth aspect, the invention relates to a method for recycling a floor layer, this floor layer mainly consisting of bonded expanded polystyrene granules, comprising the steps of:

- cutting up said bonded expanded polystyrene granules into recycled flakes.

In a preferred embodiment, the flakes are cut to an average particle size of the recycled flakes dso,rec at least 0.5 mm larger, preferably at least 1.0 mm larger, more preferably at least 1.5 mm larger, more preferably at least 2.0 mm larger, most preferably at least 2.5 mm larger than the average particle size dso, EPS of the bonded expanded polystyrene (EPS) granules being cut. This improves the compressive strength and insulation value of the recycled product.

In a preferred embodiment, the method further comprises the step of: binding the recycled flakes by means of a binding agent, preferably a polymer-in-water emulsion, even more preferably the same polymer that binds said bonded expanded polystyrene granules.

In a preferred embodiment, the recycled flakes have a density between 4 and 25 kg/m³, more preferably between 15 and 25 kg/m³.

The fifth aspect of the invention comprises an insulating floor layer formed with a kit according to the first or third aspect, or by the method according to the second aspect. This insulating floor layer is advantageous compared to aerated concrete thanks to a higher insulation value. The insulating floor layer is also lighter. Compared to conventional polymer foams, the insulating floor layer according to the present invention has a better compressive strength and is easier to install.

A floor layer according to this text can be located between the foundation and the ground floor, as well as between any two floors. The use of light insulation places less pressure on the structural elements of the building. A building according to this text can be any building, such as houses or office buildings, but also stables, warehouses and the like.

In a preferred embodiment, the final, solid insulation layer has a lambda value of less than 0.040 W/mK, preferably less than 0.037 W/mK, even more preferably less than 0.035 W/mK, even more preferably less than 0.034 W/mK, even more preferably lower than 0.033 W/mK, most preferably lower than 0.032 W/mK.

The lambda value is the coefficient of thermal conduction of a material and expresses how much heat is conducted per unit of time through a surface of Im² with a thickness of Im at a temperature difference of 1°C (IK). This is related to the thermal resistance coefficient R of a material layer with thickness d if A = R/d. These units are defined according to ISO 10456.

A low lambda value is advantageous for good insulation. It has been found that the use of a polymer based binding agent provides better thermal insulation than cement.

In a preferred embodiment, the structurally stable insulating layer has a minimum compressive strength of 100 kPa, preferably the minimum compressive strength is greater than 110 kPa, even more preferably the minimum compressive strength is greater than 120 kPa, even more preferably the minimum compressive strength is greater than 130 kPa, even more preferably the minimum compressive strength is greater than 140 kPa, even more preferably the minimum compressive strength is greater than 150 kPa.

This compressive strength is sufficient for use as a building material and a very good compromise between weight, insulation and structural element. The compressive strength is significantly higher than that of many polymer-based pre-pressed sheets and foams. In a preferred embodiment, the insulating layer has a specific gravity of 10 to 50 kg/m³, preferably 15 to 35 kg/m³, even more preferably 15 to 30 kg/m³, even more preferably a specific gravity of 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 or 29 kg/m³. A light, insulating material can be used advantageously in apartments and the like. This saves a lot of weight. In renovations, the aim is often to add insulation without modifying the structural elements of the house. Aerated concrete is often too heavy for this.

EXAMPLES

The present invention should not be construed as being limited to the embodiments described above and certain modifications or changes may be added to the examples described without having to re-evaluate the appended claims.

Expanded polystyrene granules 1

Expanded polystyrene granules were purchased as non-expanded beads. These nonexpanded beads are "white," and therefore contain no graphite or carbon. These were expanded to a limited extent in a prefoamer under the influence of steam. The prefoamer is equipped with a mixer. Prefoaming was carried out for 45s, with steam at a pressure of 0.25 bar. This steam has a temperature between 104 and 120°C.

After prefoaming, the semi-expanded polystyrene granules are dried in a drying bed. Hot air is blown from under the semi-expanded granules into this drying bed. The hot air has a temperature of about 60° at the beginning of the bed. It drops to about 40°C at the end of the bed. The granules typically undergo two cycles through the drying bed. The EPS granules remain in the drying bed for approximately 2 minutes per cycle. The dry, semi-expanded PS granules are stored in a silo, where they cool further.

The semi-expanded polystyrene granules are fully expanded in a block press measuring 4m x Im x 1.2m. Superheated steam is used for this, at a pressure of 900 bar and a temperature of 210°C, which acts on the prefoamed polystyrene granules for a short peak of 6 seconds.

The moisture absorption upon immersion, after 24 hours, was 9%.

Expanded polystyrene granules 2

Example 1 was repeated with beads of the same commercial series but a higher specific gravity. In addition, hydrophilic polymer was added to the block press steam tank in a ratio of 0.0001 wt.% to water.

The moisture absorption upon immersion of the produced EPS granules was now only 3.1%. This is probably due to the coating of EPS granules with the hydrophilic polymer in the expansion process and/or the sealing of micropores in the EPS granules by the hydrophilic polymer. Example 1: Kit

The EPS granules 1, with a diameter of 4 mm, were combined with a latex based on a dispersion copolymer. These were mixed well and poured into a mold to a height of 8 cm. Approximately 15-16 kg of beads and 14 kg of latex were used for 1 m³ of final material. These were mixed together in a concrete mixer for 2 minutes. After this, the slurry was poured into a mold. The slurry hardened into a solid insulating layer after 4 hours. The lambda value of the solid insulation layer was measured as 0.0356 W/mK. The compressive strength was 40 kPa.

Example 2: Kit met lithium silicate

For Example 2, the example was repeated according to Example 1. When mixing in the latex and the EPS granules 1, 2 kg of lithium silicate hardening solution was further added. A solid insulating layer was again produced from this.

2 kg of lithium silicate hardening agent was added. The solid insulating layer had a lambda value of 0.0364 W/mK. The compressive strength of the final material was 157 kPa.

Example 3: Kit with different EPS diameters

An insulating layer according to Example 2 was produced. Different diameters of EPS granules 1 were tested for their influence on the lambda value. The mass fraction of the EPS granules according to Examples 1-2 was thereby preserved. For EPS granules with diameters below 1 mm, dust problems were encountered. For EPS granules with diameters larger than 6 mm, the insulation value of the end result decreased sharply. For EPS granules with a diameter between 1 and 6 mm, the lambda value was always between 0.0350 W/mK and 0.0370 W/mK. For EPS granules with a diameter between 4 and 6 mm, the lambda value was always between 0.0350 W/mK and 0.0362 W/mK.

Example 4: Kit with gray EPS granules

Example 1 was repeated, but the EPS granules were now "grey" polystyrene granules. These gray granules contain graphite and are known to those skilled in the art. A solid insulating layer was again made from this. This insulation layer was also gray in color, resulting in a lower lambda value of 0.0329 W/mK.

Example 5: Kit with gray EPS granules and lithium silicate

Example 2 was repeated, with the gray polystyrene granules from Example 4. Here again, lithium silicate was found to greatly improve the compressive strength of the final material. The compressive strength was 159 kPa, and the lambda value for this product was 0.03344 W/mK. The acoustic insulation of the material was calculated to be 17 dB / 10 cm. The use of silicate significantly improved the compressive strength but had a negative impact on the insulating properties.

Example 6: Floor

Concrete foundations were laid in a new construction on a hard surface. An EPDM film was provided as a water barrier between the foundations and the surface. A slurry was produced containing 16 kg of gray EPS beads, 13 kg of latex and 2 kg of lithium silicate per Im³ of insulation material. These components were mixed in a concrete mixer for 4 minutes, forming a slurry. The slurry was poured on top of the EPDM film to the height of the foundations, with an average thickness of 8 cm. The minimum thickness was 5 cm. The slurry was leveled first with the serrated side of a rake, then with the flat side of the rake. The slurry hardened into a solid, flat insulation layer. Above this was a layer of screed followed by floor tiles.

Example 7: Floor

During a renovation, the water pipes and cable pipes for electricity and communication were exposed and partially renewed on a concrete base. A slurry of the same composition and method as Example 5 was produced in a concrete mixer. The slurry was poured on top of the concrete layer. The slurry was pressed around the pipes and tubes with a rake. The resulting layer was 12 cm high and was leveled. The pipes and tubes, except for their connections, lay completely within the flat insulation layer. Example 8: Intermediate floor

An existing intermediate floor with wooden joists and OSB boards on top was further insulated and finished. A polypropylene film was applied on top of the OSB boards. A slurry of the same composition and procedure as Example 5 was produced. This was mixed in on top of the film to a thickness of 4 cm. It was completely leveled. Above this, wood laminate was applied.

After this improvement, the floor was not only better thermally insulated, but also considerably quieter compared to stepping or walking on the intermediate floor. The applied insulation layer had an (acoustic) damping capacity.

Example 9:

Example 1 was repeated, with the EPS granules 2 with lower moisture absorption. The lambda value of the solid insulation layer was measured as 0.0321 W/mK. The compressive strength was 41 kPa.

Examples 10-12:

The insulating layer according to Examples 1, 2 and 9 was cut into flakes with an average particle size of 7 mm. The flakes were rebonded with a latex binding agent. The insulation values were 0.044 W/mK, 0.048 W/mK and 0.039 W/mK respectively for the recyclate from Examples 1, 2 and 9.

Examples 13-17

Gray EPS granules with the following properties were produced: sorption

With each series of EPS granules 13—17, 1 m³ of EPS granules was mixed with 14 kg of polymer emulsion. These were mixed well into a slurry and poured into a 20 cm high mold and leveled along the top of the mold. The insulating slurry was allowed to cure for 1 week at a temperature of 20°C.

The resulting insulating layers were tested and had the following properties:

The compressive strength was measured at 10% compression in kPa. The lambda value was determined based on the steady-state thermal resistance.

Claims

23 CLAIMS

1. Kit suitable for forming a recyclable insulating floor layer, the kit comprising:

2. Kit according to preceding claim 1, the kit comprising:

3. Kit according to preceding claim 1 or 2, wherein the plurality of expanded polystyrene (EPS) granules have a moisture absorption by immersion of up to 3%.

4. Kit according to any of the preceding claims 1-3, wherein the expanded polystyrene (EPS) granules have a density of 20-35 kg/m³ and preferably a density of 22-35 kg/m³.

5. Kit according to any of the preceding claims 1-4, wherein the expanded polystyrene (EPS) granules are coated.

6. Kit according to any of the preceding claims 1-5, wherein the binding agent has a viscosity of up to 300 mPa.s.

7. Kit according to any of the preceding claims 1-6, wherein the binding agent comprises a polymer-in-water emulsion, wherein the polymer is a styrenebutadiene copolymer.

8. Kit according to any of the preceding claims 1-7, wherein the kit has a chloride content of at most 0.1 wt.%, preferably 0.01 wt.%.

9. Kit according to any of the preceding claims 1-8, wherein the kit comprises neither cement nor lithium silicate.

10. Kit according to any of the preceding claims 1-9, wherein the kit is free of foaming agents, in particular free of polysorbate, sodium lauryl ether sulfate, sodium coceth sulfate, sodium dodecyl sulfate, sodium bicarbonate and isocyanate, especially methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI).

11. Kit according to any of the preceding claims 1-10, wherein 10 wt.% of the expanded polystyrene (EPS) granules have a particle size smaller than dio and 90 wt.% of the expanded polystyrene (EPS) granules have a particle size smaller than doo, wherein doo - dio is less than 3.0 mm, preferably less than 1.5 mm, most preferably less than 0.5 mm.

12. Kit comprising recycled material, the kit suitable for forming a re-recyclable insulating floor layer, the kit comprising:

C. a plurality of recycled flakes comprising cut up expanded polystyrene (EPS) granules, bonded by means of a first binding agent; and

D. a second binding agent, wherein the binding agent comprises a polymer-in-water emulsion.

13. Kit according to claim 12, wherein the average particle size of the recycled flakes dso,rec is at least 1 mm larger, preferably at least 2 mm larger, than the average particle size dso, EPS of the bonded expanded polystyrene (EPS) granules.

14. Kit according to any of the preceding claims 12 or 13, wherein the first binding agent and the second binding agent comprise the same polymer.

15. Kit according to any of the preceding claims 12-14, wherein the plurality of recycled flakes have a density comprised between 4 and 25 kg/m³, preferably between 15 and 25 kg/m³.