FR3095156A1 - low density polyester foam core composite profiles - Google Patents

Abstract

Process for manufacturing a composite profile comprising a polyester foam core with a density of up to 250 kg / m3 and at least on one of its surfaces a functional element applied by collateral co-extrusion, the process comprising the following steps: metering of the constituents of the foam core in a first extruder; plasticization and mixing at high temperature to melt and homogenize these constituents; injection of a foaming gas and homogenization; cooling; extrusion causing the formation of the foam core; cooling of the foam core; dosage of the constituents of the functional element in a second extruder; plasticization and mixing at high temperature to melt and homogenize these constituents; cooling; and guiding the foam core as a needle near a die of the second extruder and extrusion causing formation of the functional element on at least one surface of the foam core. (Fig. 1B)

Description

composite profiles with low density polyester foam core

The present invention relates to composite profiles comprising a core of low-density polyester foam, as well as a method of manufacturing such composite profiles.

State of the art

The simple foaming of polyester is known and well documented in the literature. Foaming down to low densities of 40-80 kg/m³ provides optimum insulation performance, but at the expense of mechanical properties. Indeed, these foams are quickly and easily compressed and deformed.

In the particular case of polyester foams, the state of the art mostly concerns extruded foams in the form of sheets, films or plates, with one or more laminated or post-extruded layers, even agglomerated on one or two main sides. EP0836937B1 teaches the co-extrusion of an unfoamed PET film onto a PET foam. EP2345538 teaches the protection against ignition of a PET foam by the addition of a non-foamed skin containing flame retardants. Although the co-extrusion or lamination processes for the application of this skin are mentioned, the preferred method uses the agglomeration of powders on a main surface of the foam, at high temperature (280°C typically) and low pressure. . However, this route does not offer the flexibility of post-extrusion technology in terms of the design of the outer layer, which must be horizontal and flat here in order to be able to "scrape" the powder in order to control its thickness. Productivity is further limited by the residence time required for the agglomeration process. The preparation of the powder constitutes an additional step prior to its application, whereas in a post-extrusion the components are directly dosed in an extruder, melted, intimately mixed and applied in one step in the geometry of a desired complex profile via the post-extrusion tool.

The co-extrusion of a dense layer on (very) low density foams is however very problematic. EP0553522A1 teaches for example the manufacture of foam composites with at least one co-extruded layer. It is essential, according to this document, to control both the temperatures of the individual flows and the pressure in the co-extrusion tool, otherwise the foamed layer will collapse if the temperature of the flow of the outer layer is too high, is under-expanded if the temperature of the outer layer flux is too low, making the flux too viscous for the foam to expand sufficiently. A sufficient pressure to avoid foaming in the co-extrusion tool must also be reached, therefore the viscosities of the fluxes must be sufficient in a very precise temperature range according to each material used.

In general, co-extrusion imposes many constraints in terms of temperature, viscosities, and possible densities, generally making it difficult, if not impossible, to obtain composites with a foamed core of (very) low density. Moreover, even if certain composites with a low density foam core can be made, their appearance is most of the time unsatisfactory. This is obviously particularly disqualifying for applications which require reduced dimensional manufacturing tolerances, as in the case of composite profiles used in many fields, in particular for window or facade elements, in the automotive field, etc.

In particular to be able to respect the constraints of geometric tolerances, other solutions favored on the market are compact profiles comprising cavities providing structural reinforcement and a certain insulating power. These solutions are nevertheless much less efficient from a thermal or acoustic insulation point of view and from a compressive strength point of view, or even from a geometry/design point of view.

To overcome at least some of these disadvantages, there are also composite profiles of this type which are formed by a similar external rigid structure, not or slightly foamed, inside which polyurethane foam is then injected and foamed in particular to improve its insulation or compressive strength properties.

In conclusion and in general, the existing solutions do not make it possible to obtain composite sections associating a (very) low density core, in particular in polyester, with one or more external layers of protection or other, and this with tolerances weak manufacturing. In addition, the known methods, even for composite sections that do not meet all of these conditions, are either difficult to master or require many manipulations, thus making them economically unattractive.

Object of the invention

An object of the present invention is therefore to find a solution making it possible to propose very light (therefore (very) low density) and/or very insulating composite profiles, in particular with one or more functional elements on at least certain faces of the profile. . It would be desirable to be able to use any kind of thermoplastic materials for these functional elements without compromising with respect to the foaming of the core. In addition, it would be desirable for the manufacturing process to be able to be carried out in line or at least without unnecessary manipulations during the process and this in the shortest possible time.

General description of the invention

1. dosage des constituants du cœur en mousse, pré-mélangés ou dosés individuellement, à l'alimentation d'une première extrudeuse ;
2. plastification et mélange des constituants du cœur en mousse à haute température pour fondre et homogénéiser ces constituants ;
3. injection d'un gaz de moussage et homogénéisation des constituants du cœur en mousse et du gaz ;
4. refroidissement de la masse obtenue ;
5. extrusion de cette masse à l'air libre à travers une filière, contrôlée en température, ayant une section de forme prédéfinie, provoquant la formation du cœur en mousse;
6. refroidissement du cœur en mousse ;
7. dosage des constituants de l’élément fonctionnel, pré-mélangés ou dosés individuellement, à l'alimentation d'une deuxième extrudeuse ;
8. plastification et mélange des constituants de l’élément fonctionnel à haute température pour fondre et homogénéiser ces constituants ;
9. refroidissement de la masse obtenue ;
10. extrusion de cette masse dans une filière dite de co-extrusion collatérale ; guidage du cœur en mousse comme pointeau pour la masse issue de ladite filière de co-extrusion collatérale, contrôlée en température, ayant une section de forme prédéfinie, provoquant la formation de ’élément fonctionnel par application sur au moins une surface du cœur en mousse.

In order to solve the problem mentioned above, the present invention proposes, in a first aspect, a method of manufacturing a profile comprising a core of polyester foam foamed without constraints in the open air with a density of up to 250 kg/m ³ , preferably from 30 to 180 kg/m ³ , in particular from 40 to 150 kg/m ³ , even more particularly from 50 to 100 kg/m³, and at least on one of its surfaces a functional element applied by so-called collateral co-extrusion, the process comprising the following steps:

1. metering of the constituents of the foam core, pre-mixed or individually metered, to feed a first extruder;
2. plasticization and mixing of the constituents of the foam core at high temperature to melt and homogenize these constituents;
3. injection of a foaming gas and homogenization of the constituents of the foam core and of the gas;
4. cooling of the mass obtained;
5. extruding this mass in the open air through a die, controlled in temperature, having a section of predefined shape, causing the formation of the foam core;
6. foam core cooling;
7. metering of the constituents of the functional element, pre-mixed or individually metered, to the feed of a second extruder;
8. plasticization and mixing of the constituents of the functional element at high temperature to melt and homogenize these constituents;
9. cooling of the mass obtained;
10. extrusion of this mass in a so-called collateral co-extrusion die; guiding the foam core as a needle for the mass coming from the said collateral co-extrusion die, controlled in temperature, having a section of predefined shape, causing the formation of the functional element by application on at least one surface of the foam core.

The above manufacturing process, known as collateral co-extrusion, makes it possible to reconcile aspects that have hitherto been considered difficult or even impossible to bring together in a product without having to implement a complex and laborious process. This is made possible mainly by the originality of the process to use the foam core as a punch for the creation of the functional element(s).

The advantages of the composite profiles that can be obtained by such a process are numerous. Firstly, the foaming of the foam core being done without constraints in the open air, the density of the foam core can be low, that is to say less than 100 kg/m ³ , or even less than 80 kg/m ³ . It is thus possible to obtain very light profiles, respectively very efficient in terms of insulation. Secondly, the polymer constituents of the functional element(s) can be chosen very freely (and therefore in a way that is well suited to the intended use of the composite profiles), especially as regards their nature, their extrusion temperature, their viscosity , their shape and/or geometric extent, etc. Third, the functional element(s) can themselves be foamed or not, depending on the needs or requirements of the final product.

The advantages of the process itself are also significant. Indeed, the principle of collateral co-extrusion developed by the inventors, makes it possible to combine the advantages of conventional co-extrusion, such as speed and the absence of intermediate manipulations, with the advantages of known batch processes, namely the association of a low-density core with an outer protective layer of various materials, or even with additional functionalities, such as sealing lips, clipping profiles, etc. As the extrusion of the functional element takes place as soon as the foam core has sufficient stability due to the cooling of the least partial portion of the foam forming the core, the process is in principle not slowed down. In particular, it is possible to carry out the method of the invention online without unnecessary manipulations. In addition, several functional elements can be added to the profile either by as many consecutive extruders or, advantageously, by a single extruder, depending on the positioning of the functional elements. By way of example, it is possible to apply two or more sealing lips to several surfaces of the foam core, or to a functional element already present on the foam core, in a single pass through an extruder by configuring the die appropriately.

In a particularly advantageous variant, the manufacturing method according to the invention further comprises step f′) of machining and/or adjusting the section of the profile in terms of shape and/or dimensions, preferably by milling, planing, (cutting) cutting, thermoforming, local densification, post-expansion, etc., after step f).

Machining and/or adjustment can be particularly useful in the case of very demanding applications in terms of geometric tolerances and/or in terms of geometric complexity of the section of the composite profile.

The polyester foam core generally comprises one or more polyester (co)polymers chosen from recycled or non-recycled (co)polymers, selected from polyethylene terephthalate (PET), thermoplastic polyester elastomers (TPC-ET, TPC, TPE-E) , PETG, PEN, PCDT, …, or any mixture thereof. In addition, in the context of the present invention, the polyester foam forming the core can comprise quantities ranging up to 49% by weight of other (co)polymers compatible or made compatible with the polyester(s) used, for example, thermoplastic elastomers (TPE), non-polar polyethylene homopolymers or copolymers (LDPE, LLDPE, MDPE, HDPE, etc.), metallocene polyethylenes (comonomer butene, hexene, octene), polypropylene homopolymers or copolymers, copolymers and/or polar terpolymers of polyethylene (EVA, EBA, EMA, EEA, E-AMH, E-GMA, E-BA-GMA, etc.), polystyrene homopolymers or copolymers (ABS, HIPS, SAN, etc.), polyphenylene oxide (PPO), polycarbonates (PC), polyamides (PA6, 66, 6.66, 10, 12, etc.), elastomeric polyamide thermoplastics (TPA), urethane elastomeric thermoplastics (TPU), (co)polymers of crosslinkable ethylene, for example silane-grafted.

As already mentioned above, the present invention makes it possible to choose the nature of the (co)polymers of the functional element(s) in a particularly free manner. In practice. the functional element(s) comprise one or more (co)polymers, whether recycled or not, chosen from thermoplastic (co)polymers, including thermoplastic elastomers (TPE), in particular polyesters (identical to or different from that of the foam core), polar copolymers of polyethylene, polyamides, polycarbonates, poly-(phenylene oxide), polystyrenes, thermoplastic elastomers urethane (TPU), homopolymers or non-polar copolymers of polyethylene (LDPE, LLDPE, MDPE, HDPE, …), metallocene polyethylenes (butene, hexene, octene co-monomer), polypropylene homopolymers or copolymers, polar polyethylene copolymers and/or terpolymers (EVA, EBA, EMA, EEA, E-AMH, E-GMA, E-BA-GMA, etc.), polystyrene homopolymers or copolymers (ABS, HIPS, SAN, etc.), polyphenylene oxide (PPO), polycarbonates (PC), polyamides (PA6, 66, 6.66, 10, 12, …), elastomeric polyamide thermoplastics (TPA), thermoplastics urethane elastomers (TPU), crosslinkable ethylene (co)polymers, for example silane-grafted, etc., or their mixtures, reinforced or not with fibers, in particular glass fibers, carbon fibers, etc.

As mentioned, the functional element or elements may themselves be foamed or not. If they are foamed, the manufacturing process further comprises step h') of injecting a foaming gas into the second extruder and homogenizing the constituents and the gas before step i).

Depending on the requirements of the intended application of the composite profiles, it may be advantageous, especially in the case of foamed functional elements, to provide a step k), in particular a step k1) of calibrating the functional element, and/or according to needs a step k2) of drawing the composite profile.

A particularity of this method of manufacturing a profile is that it makes it very easy to add or integrate other elements to the composite profiles. For example, in an advantageous variant, the method comprises a step of incorporating third-party/additional functional elements in and/or on the foam core and/or in one of the functional elements, in particular reinforcing elements, for example reinforcing elements in organic or inorganic fibres, woven, non-woven, knitted, textile or metallic, before step j).

As already mentioned above, the present process for manufacturing a composite profile is advantageously carried out in such a way as to carry out steps g) and following directly once the foam core has set, that is to say when it has sufficient dimensional stability for the application of the functional element.

It should be noted that steps g) and following can be carried out consecutively in several extruders or simultaneously in a single extruder for the application of multiple functional elements.

Another important aspect of the invention relates to foam profiles comprising a core of polyester foam foamed in the open air with a density of up to 250 kg/m ³ , preferably from 30 to 180 kg/m ³ , in particular from 40 to 150 kg/m ³ , more particularly still from 50 to 100 kg/m³, and at least on one of its surfaces a functional element applied by so-called collateral co-extrusion, preferably by means of a manufacturing process of a profile as described in this document.

The invention also proposes, in a second aspect, composite foam sections comprising a core of polyester foam foamed in the open air with a density of up to 250 kg/m ³ , preferably from 30 to 180 kg/m ³ , in particular from 40 to 150 kg/m ³ , more particularly still from 50 to 100 kg/m³, and at least on one of its surfaces a functional element applied by collateral co-extrusion, preferably by means of a process of manufacture of a composite profile as described here.

Preferably, as already mentioned, the foam core has been worked by machining and/or adjustment in terms of shape and/or dimensions, preferably by milling, planing, (cutting), thermoforming, local densification, post-expansion , ….

In certain embodiments, the composite foam profiles incorporate third functional elements in and/or on the foam core, in particular reinforcing elements, for example metallic reinforcing elements.

A third aspect of the invention relates to the use of a composite profile according to the invention or of a composite profile obtained with a manufacturing process according to the invention in thermal and/or acoustic insulation, sealing, damping intended to attenuate or eliminate oscillations or vibrations, stiffening, or lightening, as assembly or structural elements and/or sealing of doors, windows and facades, decoration, etc. , in particular in the fields of construction, automotive, aviation, or others.

A functional element in the sense of the present invention is an element or a structure added to the surface of the composite foam profiles to give them some particular (local) function. It can be any type of function, in particular sealing, assembly or fixing, in particular as a "male" or "female" coupling element, reinforcement, stiffening, protection, more precise sizing ( reduction of dimensional manufacturing tolerances), decoration, aesthetic or haptic finish (finish to the touch), etc. It should be noted that a functional element can simultaneously have several of these functions and composite foam profiles can include several distinct functional elements having in turn one or more different functions.

The expressions "composite profile" or "composite foam profile" in the sense of the invention are profiles comprising a core of polyester foam, this core having been obtained by foaming in the open air, therefore without external constraints during the foaming , resulting in a core of polyester foam of reduced density ranging up to 250 kg/m ³ , preferably from 40 to 150 kg/m ³ , more particularly from 50 to 100 kg/m ³ . Unlike the foamed polyester core, the functional element(s) can be foamed or not, in polyester or in another composite material or not.

In summary, the invention therefore proposes in a first aspect a method aimed at modifying a polyester foam (for example PET), with open or closed cells, by adding to it one or more functional elements, whether foamed or not. They partially or completely cover the outer surface of the foam. These functional elements can be of various composition depending on the end use and the properties to be obtained. They can form a contour or a protection around the foam core or they can also add another particular functionality to the foam, such as the possibility of clipping, sealing, etc. The functional element can generally provide mechanical reinforcement, better shock absorption, UV protection, fire protection, visual or haptic modification to the foam, etc.

For example, a functional element made of polyolefins or thermoplastic elastomers aims at an aesthetic and haptic modification of the foam thus covered or the sealing of the resulting composite profile.

The addition of a functional element made of polyester, polyamide, polycarbonate, poly-(phenylene oxide), polystyrene, whether or not reinforced with fibers, in particular glass fibers, carbon fibers, etc., for example, makes it possible to improve the hardness and compressive strength of polyester foams (e.g. PET).

As mentioned, functional elements can be foamed or not. The foaming of the functional element makes it possible, for example, to improve the thermal insulation properties while increasing the hardness of the composite profiles, if desired (optimization of the performance/weight ratio of the composite).

These functional elements are applied by collateral co-extrusion, at thicknesses ranging for example from 100 μm to 5 mm.

Description of the drawings

Other particularities and characteristics of the invention will emerge from the detailed description of some advantageous embodiments presented below, by way of illustration, with reference to the appended drawings. These show:

is a cross section A) of a hollow profile 10 with walls 11 forming empty compartments 15 of the state of the art and

is a cross section of a composite profile 20 according to the invention for the same use comprising a foam core 25 to which a first functional element 21 has been applied, namely a peripheral layer, provided with a second functional element 22, namely a connecting element; and

is a cross section A) of a hollow section 30 with walls 31 forming empty compartments 35 of the state of the art and

is a cross section B) of a corresponding composite profile 40 according to the invention for the same use comprising a foam core 45 on which a first functional element 42 has been applied, namely a peripheral layer, provided with a second element functional 41 in the form of attachment elements, for example adapted to receive the connectors 22 of the section of [Fig. 1B].

Claims (13)

Process for the manufacture of a composite profile comprising a core of foamed polyester foam without constraints in the open air with a density of up to 250 kg/m ³ , preferably of 40 to 150 kg/m ³ , more particularly still of 50 to 100 kg/m ³ , and at least on one of its surfaces a functional element applied by so-called collateral co-extrusion, the method comprising the following steps:
a) metering of the constituents of the foam core, pre-mixed or individually metered, to the feed of a first extruder;
b) plasticizing and mixing the constituents of the foam core at high temperature to melt and homogenize these constituents;
c) injection of a foaming gas and homogenization of the constituents of the foam core and of the gas;
d) cooling of the mass obtained;
e) extrusion of this mass in the open air through a die, controlled in temperature, having a section of predefined shape, causing the formation of the foam core;
f) foam core cooling;
g) metering of the constituents of the functional element, pre-mixed or individually metered, at the feed of a second extruder;
h) plasticization and mixing of the constituents of the functional element at high temperature to melt and homogenize these constituents;
i) cooling of the mass obtained;
j) extrusion of this mass in a so-called collateral co-extrusion die comprising guiding the foam core as a needle for the mass coming from the said die, controlled in temperature, having a section of predefined shape, causing the formation of the element functional by application to at least one surface of the foam core. Method of manufacturing a profile according to claim 1, in which the polyester foam core comprises one or more (co)polymers, whether recycled or not, of polyester chosen from polyethylene terephthalate, PET, thermoplastic polyester elastomers, in particular TPC-ET, TPC or TPE-E, PETG, PEN, PCDT, or any mixture thereof. Process for manufacturing a composite profile according to claim 1 or 2, in which the functional element comprises one or more (co)polymers, whether recycled or not, chosen from thermoplastic (co)polymers, including thermoplastic elastomers, TPE, in particular polyesters, polar copolymers of polyethylene, polyamides, polycarbonates, poly-(phenylene oxide), polystyrenes, thermoplastic elastomers urethane, TPU, homopolymers or non-polar copolymers of polyethylene, in particular LDPE, LLDPE, MDPE and/or HDPE, metallocene polyethylenes comprising in particular butene, hexene and/or octene comonomers, polypropylene homopolymers or copolymers, polar polyethylene copolymers and/or terpolymers, in particular EVA, EBA, EMA, EEA, E- AMH, E-GMA and/or E-BA-GMA, polystyrene homopolymers or copolymers, in particular ABS, HIPS and/or SAN, polyphenylene oxide, PPO, polycarbonates, PC, polyamides, in particular PA6, 66, 6.66, 10 and/or 12, elastomeric polyamide thermoplastics, TPA, urethane elastomeric thermoplastics, TPU, crosslinkable ethylene (co)polymers, for example silane-grafted, or mixtures thereof, reinforced or not with fibers, preferably glass or carbon fibers. Method of manufacturing a composite profile according to any one of the preceding claims, further comprising a step f') of machining and/or adjusting the section of the profile in terms of shape and/or dimensions, preferably by milling, planing, (cutting) cutting, thermoforming, local densification, post-expansion, after step f) and/or a step h′) of injection of a foaming gas into the second extruder and homogenization of the constituents and gas before step i) and/or a step k) of calibrating the functional element and/or pulling the profile and/or a step of incorporating third-party functional elements in and/or on the foam core , in particular reinforcing elements, for example reinforcing elements made of organic or inorganic fibers, woven, nonwoven, knitted, textile or metallic, before step j). Process for the manufacture of a composite profile according to any one of the preceding claims, in which the steps g) and following are carried out consecutively in several extruders or simultaneously in a single extruder for the application of multiple functional elements and/or all the steps are done online. Profile of composite foam comprising a core of polyester foam foamed in the open air with a density of up to 250 kg/m ³ , preferably from 40 to 150 kg/m ³ , more particularly from 50 to 100 kg/m ³ , and at least on one of its surfaces a functional element applied by so-called collateral co-extrusion. Composite foam profile according to claim 6, obtained by means of a method of manufacturing a profile according to any one of the preceding claims Composite foam profile according to Claim 6 or 7, in which the foam core has been worked by machining and/or adjustment in terms of shape and/or dimensions, preferably by milling, planing, (cutting) cutting, thermoforming, local densification and/or post-expansion. Composite foam profile according to any one of Claims 6 to 8, in which the polyester foam core comprises one or more one or more recycled or non-recycled polyester (co)polymers chosen from polyethylene terephthalate PET, thermoplastic polyester elastomers, including TPC-ET, TPC and/or TPE-E, PETG, PEN, PCDT, or any mixture thereof. Composite foam profile according to any one of Claims 6 to 9, in which the functional element comprises one or more (co)polymers chosen from recycled or non-recycled (co)polymers chosen from thermoplastic (co)polymers, including thermoplastic elastomers, TPE, in particular polyesters, polar copolymers of polyethylene, polyamides, polycarbonates, poly-(phenylene oxide), polystyrenes, thermoplastic elastomers urethane, TPU, homopolymers or non-polar copolymers of polyethylene , in particular LDPE, LLDPE, MDPE and/or HDPE, metallocene polyethylenes comprising in particular butene, hexene and/or octene comonomers, polypropylene homopolymers or copolymers, copolymers and/or polar terpolymers of polyethylene, in particular EVA, EBA , EMA, EEA, E-AMH, E-GMA and/or E-BA-GMA, polystyrene homopolymers or copolymers, in particular ABS, HIPS and/or SAN, polyphenylene oxide, PPO, polycarbonates, PC , polyamides, in particular PA6, 66, 6.66, 10, and/or 12, elastomeric polyamide thermoplastics, TPA, urethane elastomeric thermoplastics, TPU, crosslinkable ethylene (co)polymers, for example silane-grafted, or mixtures thereof , reinforced or not with fibres, preferably with glass or carbon fibres. Composite foam profile according to any one of Claims 6 to 10, in which the functional element is foamed. Composite foam profile according to any one of Claims 6 to 11, incorporating third-party functional elements in and/or on the foam core, in particular reinforcement elements, for example metal reinforcement elements. Use of a composite profile according to any one of Claims 6 to 12 or of a composite profile obtained by a manufacturing process according to any one of Claims 1 to 5 in thermal and/or acoustic insulation applications, sealing, damping intended to attenuate or eliminate oscillations or vibrations, stiffening, as elements for assembling and/or sealing doors, windows and facades, decoration, in particular in the fields of construction , automotive, aviation.