BE1020760A3 - FOAMS BASED ON BUTENE AND ETHYLENE. - Google Patents

Description

Foams based on butene and ethylene

The present invention relates to foams based on butene and ethylene and more particularly foams based on butene-1 and ethylene.

Foams of polyethylene and LLDPE ("linear low-density polyethylene", a copolymer based on ethylene and an α-olefin) are already described for example in the document EP1373401.

The LLDPE used, however, is a copolymer which is very rich in ethylene and poor in α-olefin.

The foams obtained thus have the characteristics of foams based on polyethylene. These foams consequently have, for example, relatively good insulating properties, but flexibility or flexibility that is too low for certain applications.

On the other hand, foams based on a mixture of polyethylene and a polymer based on an α-olefin or a copolymer based on ethylene and on an α-olefin are also described in US Pat. document DE102009028200.

These foams may be richer in α-olefin and in particular in polybutene-1. However, when using a mixture of polyethylene and polybutene-1 or a mixture of polyethylene and a copolymer of ethylene and butene-1, rich in butene-1, we obtain foams whose mechanical strength is bad.

In this respect, it is known that polybutene-1 and polyethylene are not compatible. They form distinct phases (phase separation).

Indeed, this incompatibility is even used because films of a mixture of polybutene-1 and polyethylene are used as "easy peel" films (easy peel). These films are used for example in the field of packaging to allow easy opening. Under duress the film cracks and splits quickly.

These films, which comprise polybutene nodules or a butene-rich phase dispersed in a polyethylene phase or rich in ethylene, are weakened because the interface between polyethylene and polybutene is fragile. Within such a film, the cracks propagate easily between and / or especially at the interfaces between the polybutene nodules or dispersed butene rich phase (s) and the polyethylene or the ethylene-rich phase.

The incompatibility between polybutene-1 and polyethylene therefore leads to poor mechanical properties.

However for some applications, it would be interesting to have a very flexible foam and nevertheless have good mechanical properties.

This is possible thanks to the foams based on butene and ethylene according to the present invention and according to independent claim 1. In addition, the present invention also relates to a foaming process making it possible to obtain foams based on butene and on ethylene according to the present invention and according to independent claim 12.

Other embodiments of the foams and the foaming process according to the present invention are described in the dependent claims.

The present invention relates to foams based on butene and ethylene, which comprise at least one ethylene-based polymer rich in ethylene and at least one butene-based polymer rich in butene-1, the temperature melting thereof being less than 135 ° C.

This makes it possible to obtain very flexible foams having good mechanical properties.

Indeed, the use / addition of a butene-based polymer and rich in butene-1 makes it possible to greatly increase the flexibility / flexibility of the foams obtained. Moreover, this also makes it possible to maintain excellent flexibility / flexibility of the foams obtained over a wide temperature range. In particular, this makes it possible to ensure good flexibility / flexibility at high temperature (for example greater than 40 ° C.) and / or at low temperature (for example less than 20 ° C.).

On the other hand, the fact of using at least one butene-based polymer rich in polybutene-1, whose melting temperature is below 135 ° C., makes it possible, surprisingly, to obtain foams with excellent mechanical properties. In addition, the polyethylene component provides good properties in terms of thermal insulation. Furthermore, the use / addition of a butene-based polymer rich in butene-1 may further improve these thermal insulation properties.

An ethylene-rich polymer which is rich in ethylene may for example be at least one homopolymer or at least one ethylene copolymer. An ethylene-rich polymer that is rich in ethylene may be, for example, at least one polymer chosen from the following group: very low density polyethylene (PE-TBD / VLDPE), linear low density polyethylene (PE-BDL / LLDPE), low density polyethylene (PE-BD / LDPE), medium density polyethylene (PE-MD / MDPE), high density polyethylene (PE-HD / HDPE), very low molecular weight polyethylene ( ULMWPE), high molecular weight polyethylene (HMWPE).

An ethylene-based polymer may also be, for example, at least one copolymer, at least one block copolymer, at least one gradient copolymer, at least one random copolymer, at least one graft copolymer, at least one interpolymer or at least one a copolymer which represents a combination of several of these types of copolymers. A copolymer is a polymer which comprises at least two different monomers.

A butene-based ethylene-based foam according to the present invention may comprise at least one ethylene-rich and ethylene-rich polymer, which may preferably for example comprise at least 50%, preferably at least 51%, of preferably at least 55%, preferably at least 60%, preferably at least 70%, preferably at least 75%, preferably at least 80%, preferably at least 85%, preferably at least 90%, preferably at least 95%, preferably at least 97%, preferably at least 98% or at least 99% by weight of ethylene. Rich in ethylene may therefore mean for example comprising at least 50%, preferably at least 51%, preferably at least 55%, preferably at least 60%, preferably at least 70%, preferably at least 75%, preferably at least 80%, preferably at least 85%, preferably at least 90%, preferably at least 95%, preferably at least 97%, preferably at least 98% or at least 99% by weight ethylene. This allows for example to obtain foams having for example good thermal insulation properties.

A foam according to the present invention may in one embodiment for example comprise low density polyethylene (PE-BD / LDPE) as an ethylene-based and ethylene-rich polymer. The low density polyethylene can be obtained for example by radical polymerization of ethylene. The rate of connection of low density polyethylene is higher than the rate of connection of high density polyethylene (PE-HD / HDPE). The low density polyethylene may for example have a density of about 0.91 to 0.935 g / cm3.

A butene-based ethylene-based foam according to the present invention may comprise at least one ethylene-rich and ethylene-rich polymer whose melting temperature determined by DSC may, for example, be between 30 ° C. and 160 ° C. C, preferably between 40 ° and 155 ° C, preferably between 45 ° C and 150 ° C, preferably between 60 ° C and 147 ° C, preferably between 70 ° C and 146 ° C, preferably between 80 ° C C and 145 ° C, preferably between 85 ° C and 144 ° C, preferably between 90 ° C and 143 ° C, preferably between 95 ° C and 140 ° C, preferably between 100 ° C and 135 ° C, preferably between 102.5 ° C and 132.5 ° C, preferably between 105 ° C and 130 ° C, preferably between 105 ° C and 115 ° C or between 120 ° C and 130 ° C.

The melting temperature of an ethylene-rich ethylene-rich polymer determined by DSC can for example be in the case of low-density polyethylene (PE-BD / LDPE) be between 90 ° C and 120 ° C, preferably between 105 ° C and 118 ° C, preferably between 105.5 ° C and 117.5 ° C, preferably between 106 ° C and 117 ° C, preferably between 107 ° C and 115 ° C, preferably between 107 ° C and 115 ° C, preferably between 107 ° C and 115 ° C, preferably between 107 ° C and 115 ° C , 5 ° C and 114.5 ° C, preferably between 110 ° C and 114.25 ° C, preferably between 111 ° C and 114 ° C.

The melting point of an ethylene-rich ethylene-rich polymer, determined by DSC, can for example be in the case of high density polyethylene (PE-HD / HDPE) be between 115 ° C and 135 ° C, preferably between 120 ° C and 130 ° C, preferably between 122.5 ° C and 127.5 ° C.

A butene-based ethylene-based foam according to the present invention may comprise at least one ethylene-rich and ethylene-rich polymer, which may have a melt flow index (melt flow index) for example measured at room temperature. 190 ° C with a standard mass of 2.16 kg (ISO 1133), which may be for example between 0.1 and 35 g / 10 min, preferably between 0.15 and 30 g / 10 min, preferably between 0.2 and 25 g / 10 min, preferably between 0.225 and 12 g / 10 min, preferably between 0.25 and 8 g / 10 min, preferably between 0.3 and 5 g / 10 min, preferably between between 0.325 and 4 g / 10 min, preferably between 0.35 and 0.8 g / 10 min, preferably between 0.6 and 0.7 g / 10 min.

A butene and ethylene based foam according to the present invention may comprise at least one butene-based polymer, which may preferably for example comprise at least 25%, preferably at least 30%, preferably at least 35% preferably at least 40%, preferably at least 45%, preferably at least 50%, preferably at least 55%, preferably at least 60%, preferably at least 65%, preferably at least 70%, preferably at least 75%, preferably at least 80%, preferably at least 85%, preferably at least 90%, preferably at least 95%, preferably at least 97%, preferably at least 98% or at least less than 99% by weight of butene-1. Rich in butene-1 may therefore mean for example comprising at least 50%, preferably at least 51%, preferably at least 55%, preferably at least 60%, preferably at least 70%, preferably at least 70%. %, preferably at least 80%, preferably at least 85%, preferably at least 90%, preferably at least 95%, preferably at least 97%, preferably at least 98% or at least 99% by weight butene-1. This allows for example to obtain foams with great flexibility / flexibility.

A butene-based polymer and / or a butene-based polymer rich in butene-1 can be, for example, a polymer comprising butene-1, 2-butene-2, E-butene-2 and / or or 2-methylpropene.

A butene and ethylene-based foam according to the present invention may comprise at least one butene-based polymer rich in butene-1, which may preferably for example comprise at least 50%, preferably at least 51%, preferably at least 55%, preferably at least 60%, preferably at least 65%, preferably at least 70%, preferably at least 75%, preferably at least 80%, preferably at least 85%, preferably preferably at least 90%, preferably at least 95%, preferably at least 97%, preferably at least 98%, preferably at least 99%, preferably at least 99.5%, preferably at least 99.9%, preferably at least 99%; at least 99.99%, preferably at least 99.999% by weight of butene-1. This provides foams with great flexibility / flexibility. Furthermore, a butene-based polymer rich in butene-1 may also improve the tolerance to additives (fillers) and / or thermal insulation properties.

A butene-based ethylene-based foam according to the present invention may comprise at least one butene-based polymer rich in butene-1, which may preferably for example have a melt flow index (melt flow index or melt flow rate). ) for example measured at 190 ° C. with a standard mass of 2.16 kg (ISO 1133 standard), which may for example be between 0.3 and 2 g / 10 min, preferably between 0.325 and 1.5 g / 10 min. preferably between 0.35 and 1 g / 10 min, preferably between 0.45 and 0.95 g / 10, preferably between 0.4 and 0.6 g / 10 min or between 0.7 and 0, 9 g / 10min.

A butene-based ethylene-based foam according to the present invention may comprise at least one butene-based polymer rich in butene-1, which may be for example a copolymer, a block copolymer, a gradient copolymer, a random copolymer, a graft copolymer, an interpolymer or a copolymer, which represents a combination of several of these types of copolymers. A copolymer may be a polymer that comprises at least two different monomers. The addition of a second and / or another monomer and the use of a copolymer makes it possible to modify and / or adapt the melting temperature of a butene-based polymer easily. In addition, the structure / nature of the copolymer can also influence the melting temperature. This makes it possible, for example, to reduce the melting temperature and / or to obtain a melting temperature, for example less than 135 ° C., while preserving the properties (and particularly the great flexibility / flexibility) of the polybutene-1.

A butene and ethylene based foam according to the present invention may comprise at least one butene-based polymer, which may be for example a copolymer comprising butene-1 and at least one other α-olefin. A butene-based polymer may for example be a copolymer comprising butene-1 and ethylene and / or propylene. The polymer-based use of butene, which is a copolymer comprising butene-1 and at least one other α-olefin, makes it possible to reduce the melting temperature of the butene-based polymer. Indeed, the incorporation of at least one other α-olefin, such as for example ethylene and / or propylene, in a copolymer comprising butene-1 and at least one other α-olefin may, for example, make it possible to to reduce the melting point of the copolymer, for example with respect to polybutene-1. The incorporation / addition of at least one other α-olefin, such as ethylene and / or propylene, to a butene-based polymer, to obtain a copolymer comprising butene-1 and at least one other α-olefin, can indeed possibly disrupt the crystallization of polybutene-1 and the formation of corresponding crystalline domains. This may, for example, lead to a decrease in the melting temperature of the polymer / copolymer, for example. In addition, the melting temperature of a butene-1-rich copolymer comprising butene-1 and at least one other α-olefin may preferably for example decrease when the content of α-olefin (for example ethylene and / or propylene) increases. This makes it possible, for example, to reduce the melting temperature and / or to obtain a melting temperature, for example less than 135 ° C., while preserving the properties (and particularly the great flexibility / flexibility) of the polybutene-1.

A butene-based polymer rich in butene-1 may, for example, be a copolymer comprising two monomers. A butene-based polymer rich in butene-1 may therefore for example be a copolymer comprising butene-1 and ethylene or propylene. Preferably a butene-based polymer rich in butene-1 may for example be a copolymer comprising butene-1 and ethylene. This makes it possible to avoid any alterations in the properties due to the presence of one or more additional types of monomers.

A butene-based polymer rich in butene-1 may, for example, comprise only a few units of another monomer. A butene-based polymer rich in butene-1 may, for example, comprise between 0.001% and 10%, preferably between 0.1% and 9%, preferably between 0.2% and 8%, preferably between 0.3% and 7%, preferably between 0.4% and 6%, preferably between 0.5% and 5.5%, preferably between 0.7% and 5%, preferably between 0.9% and and 4.5%, preferably between 1% and 4% of another monomer, for example another α-olefin, such as ethylene or propylene. This makes it possible, for example, to reduce the melting temperature and / or to obtain a melting temperature, for example less than 135 ° C., while preserving the properties (and particularly the great flexibility / flexibility) of the polybutene-1.

For example, a butene-based polymer rich in butene-1 may, for example, comprise only about 100, 50, 25, 10 or 3 units of another monomer. This also makes it possible, for example, to reduce the melting temperature and / or to obtain a melting temperature, for example less than 135 ° C., while retaining the properties (and particularly the great flexibility / flexibility of the polybutene-1).

A butene-based ethylene-based foam according to the present invention may comprise at least one butene-based polymer and / or a butene-1-butene-1-based polymer, whose melting temperature determined by DSC may be for example less than 135 ° C, preferably less than 134 ° C, preferably less than 133 ° C, preferably less than 132 ° C, preferably less than 131 ° C, preferably less than 130 ° C, preferably less than 129.5 ° C, preferably less than 129 ° C, preferably less than 128.5 ° C, preferably less than 128 ° C, preferably less than 127.5 ° C, preferably less than 127 ° C C, preferably less than 126.5 ° C, preferably less than 126 ° C, preferably less than 125.5 ° C, preferably less than 125 ° C, preferably less than 124.5 ° C, preferably less than 124 ° C, preferably less than 123.5 ° C, preferably less than 123 ° C, preferably less than 122.5 ° C, preferably less than 122 ° C, preferably less than 121.5 ° C, preferably less than 121 ° C C, preferably less than 120.5 ° C, preferably less than 120 ° C, preferably less than 119.5 ° C, preferably less than119 ° C, preferably less than 118.5 ° C, preferably less than 118 ° C, preferably less than 117.5 ° C, preferably less than 117 ° C, preferably less than 116.5 ° C, preferably less than 116 ° C, preferably less than 115.5 ° C, preferably less than 115 ° C, preferably less than 114.5 ° C, preferably less than 114 ° C, preferably less than 113.5 ° C, preferably less than 113 ° C, preferably less than 112, 5 ° C, preferably less than 112 ° C, preferably less than 11.5 ° C preferably less than 111 ° C, preferably less than 110.5 ° C, preferably less than 110 ° C, preferably less than 107.5 ° C or preferably less than 105 ° C. Experiments carried out in the context of the present invention have made it possible to observe that the use of a butene-based polymer rich in butene-1, the melting temperature of which is preferably less than 135 ° C., for example, to obtain a a mixture of an ethylene-based polymer rich in ethylene on the one hand and a butene-based polymer rich in butene-1 on the other, makes it possible to improve, surprisingly, the mechanical properties of the foams based on butene and ethylene, according to the present invention, obtained thanks to this mixture.

A butene-based ethylene-based foam according to the present invention may comprise at least one butene-based polymer and / or a butene-1-butene-1-based polymer, whose melting temperature determined by DSC may be for example greater than 60 ° C, preferably greater than 70 ° C, preferably greater than 75 ° C, preferably greater than 80 ° C, preferably greater than 85 ° C, preferably greater than 90 ° C, preferably greater than 95 ° C, preferably greater than 100 ° C, preferably greater than 105 ° C, preferably greater than 106 ° C, preferably greater than 106.5 ° C, preferably greater than 107 ° C, preferably greater than 108 ° C, preferably greater than 109 ° C, preferably greater than 110 ° C, preferably greater than 111 ° C, preferably greater than 111.5 ° C, preferably greater than 112 ° C, preferably greater than at 112.5 ° C, preferably greater than 113 ° C or preferably greater than 113.5 ° C. This allows for example to ensure good mechanical strength foams based on butene and ethylene according to the present invention at higher temperature.

The melting temperature of a polymer or a copolymer can be determined for example by differential scanning calorimetry (DSC). The melting temperature of a polymer or copolymer may preferably be the melting temperature which corresponds to the maximum (peak) of a detected melting peak in DSC. The melting temperature of a polymer or copolymer may also be a temperature range which corresponds to a melting peak (beginning and end of the peak) detected in DSC. The melting temperature of a polymer or copolymer may also be an average of the start value and the end value of a temperature range corresponding to a detected melting peak in DSC (average value start and end value of the peak).

The melting temperature may for example be measured by DSC by heating a sample in a sealed capsule up to 180 ° C with a temperature ramp of 10 ° C per minute. Alternatively it is for example also possible to proceed to a first heating up to 180 ° C with a temperature ramp of 10 ° C per minute, to maintain the temperature at 180 ° C for example for 5 minutes, to cool the sample up to -20 ° C with a temperature ramp of 10 ° C per minute, hold the sample at -20 ° C for eg 5 minutes and then proceed to a second heat up to 180 ° C with a temperature ramp of 10 ° C per minute, to measure the melting temperature during this second heating.

The melting temperature of a polymer or copolymer may preferably be the melting temperature of the majority form of this polymer or copolymer. The melting temperature of a polymer or copolymer may therefore preferably be the melting temperature which corresponds to the peak detected in DSC, the area under the peak is the largest.

The melting temperature of a polymer or copolymer may also preferably be the melting temperature determined for the thermodynamically most stable form of this polymer or copolymer. For a polymer and / or a copolymer comprising several polymorphic forms, for example polybutene-1 and / or a copolymer comprising butene-1, the melting temperature of the polymer may be the melting temperature of the thermodynamically most stable form. of this polymer (for example Form I in the case of polybutene-1) or copolymer.

A butene-based ethylene-based foam according to the present invention may comprise at least one ethylene-rich and ethylene-rich polymer on the one hand and at least one butene-butene-1-rich butene-1-based polymer. on the other hand, so that the difference between the melting temperatures of ethylene / ethylene-rich polymer and / or butene-1 / butene-1 / butene-1-based polymer on the other hand may be for example less than 40 ° C, preferably less than 35 ° C, preferably less than 30 ° C, preferably less than 25 ° C, preferably less than 20 ° C, preferably less than 15 ° C, preferably less than 10 ° C, preferably less than 6 ° C, preferably less than 3 ° C, preferably less than 2 ° C. When using several ethylene-rich polymers rich in ethylene and / or several butene-based polymers rich in butene-1, the difference between the melting temperatures for each pair of polymers used may for example be minus 40 ° C, preferably less than 35 ° C, preferably less than 30 ° C, preferably less than 25 ° C, preferably less than 20 ° C, preferably less than 15 ° C, preferably less than 10 ° C, preferably less than 6 ° C, preferably less than 3 ° C, preferably less than 2 ° C. Experiments carried out in the context of the present invention have made it possible to observe that the use of a mixture comprising an ethylene-rich polymer and an ethylene-rich polymer on the one hand and a butene-based and butene-rich polymer. 1 on the other hand, whose melting temperatures are similar / similar, makes it possible to further improve the mechanical properties of the foams obtained. This may make it possible, for example, to avoid an excessive difference in the properties and particularly, for example, in terms of the viscosity and / or the crystallinity of the ethylene-based and ethylene-rich polymer on the one hand and the polymer on the other hand. butene base and rich in butene-1 on the other hand during the implementation and / or mixing and / or extrusion and / or accounting and / or foaming. This may therefore, for example, make it possible to improve the homogeneity of the polymer blend and thus contribute to facilitating or improving, for example, the use and / or mixing and / or extrusion of the polymer blend and / or the accounting and / or the stability of the interface between the rich polybutene-1 phase and the polyethylene-rich phase and / or to improve the mechanical properties of the foams obtained.

A butene-based ethylene-based foam according to the present invention may comprise at least one ethylene-rich and ethylene-rich polymer on the one hand and at least one butene-butene-1-rich butene-1-based polymer. on the other hand, so that the difference between the melt flow index (melt flow index) for example measured at 190 ° C with a standard mass of 2.16 kg (ISO 1133 standard) of a polymer ethylene-rich and ethylene-rich, on the one hand, and butene-1-based butene-based polymer, on the other hand, may preferably be, for example, less than 25 g / 10 min, preferably minus 24 g / 10 min, preferably minus 23.5 g / 10 min, preferably minus 23 g / 10 min, preferably minus 20 g / 10 min, preferably minus 17.5 g / 10 min. min, preferably minus 15 g / 10 min, preferably minus 12.5 g / 10 min, preferably minus 10 g / 10 min, preferably minus 7.5 g / 10 min, preferably e of minus 5 g / 10 min, preferably minus 2.5 g / 10 min, preferably minus 2 g / 10 min, preferably minus 1.5 g / 10 min, preferably minus 1.25. g / 10 min, preferably minus 1.2 g / 10 min, preferably minus 1 g / 10 min, preferably minus 0.8 g / 10 min, preferably minus 0.5 g / 10 min, preferably less than 0.3 g / 10 min, preferably minus 0.2 g / 10 min. When using several polymers based on ethylene and rich in ethylene and / or several butene-based polymers and rich in butene-1, the difference between the melt flow index (melt flow index) for example measured at 190 ° C. with a standard mass of 2.16 kg (ISO 1133 standard) for each pair of polymers used may preferably be, for example, less than 25 g / 10 min, preferably less than 24 g / 10 min, of preferably minus 23.5 g / 10 min, preferably minus 23 g / 10 min, preferably minus 20 g / 10 min, preferably minus 17.5 g / 10 min, preferably minus 15 g / 10 min. 10 min, preferably minus 12.5 g / 10 min, preferably minus 10 g / 10 min, preferably minus 7.5 g / 10 min, preferably minus 5 g / 10 min, preferably minus 2.5 g / 10 min, preferably minus 2 g / 10 min, preferably minus 1.5 g / 10 min, preferably minus 1.25 g / 10 min, preferably minus 1.2 g / 10 min, preferably minus 1 g / 10 min, preferably minus 0.8 g / 10 min, preferably minus 0.5 g / 10 min, preferably minus 0.3 g / 10 min, preferably minus 0.2 g / 10 min. This can furthermore make it possible, for example, to avoid a too great difference in properties and particularly for example in terms of the viscosity of the ethylene-based and ethylene-rich polymer on the one hand and the butene-based polymer and rich in butene-1 on the other hand, especially in the molten state. This may therefore also possibly contribute to facilitating or improving, for example, the implementation and / or the mixing and / or the extrusion and / or the accounting and / or the stability of the interface between the polybutene-1-rich phase and the polyethylene-rich phase and / or to improve the mechanical properties of the foams obtained.

The foams according to the present invention may also comprise at least one additive (filler). These additives may, for example, comprise at least one additive that improves the insulating and particularly thermal insulation properties, such as for example at least one additive comprising carbon black, carbon nanotubes, fullerenes and / or flakes ( flakes) / metal particles, in particular aluminum flakes. On the other hand, these additives may also comprise at least one additive which facilitates the implementation and / or foaming, such as for example at least one additive comprising talc, a mixture of talc and polyethylene, a mixture of talc and LDPE, one or more clays, titanium dioxide, silicon dioxide, Γ EVA and / or one or more fatty acid esters and / or glycerol esters, such as for example one or more stearate (s), such as for example, barium stearate, sodium stearate, glycerol stearate and / or glycerol alpha-monostearate, and / or one or more fatty acid amides, for example stearamide or palmitamide, and / or or at least one derivative of at least one of these compounds / additives and / or a mixture of at least two of these compounds / additives. In addition, at least one additive may also comprise, for example, at least one stabilizer, at least one UV absorber, at least one plasticizer and / or at least one flame retardant and / or at least one derivative of at least one of these compounds / additives and / or a mixture of at least two of these compounds / additives.

The foams according to the present invention based on ethylene and butene may for example have open cells and / or closed cells. For example, open cells and / or closed cells may be obtained depending on the extrusion and / or foaming conditions. For example, open cells may also be obtained by mechanical perforation of closed cell foams or by temperature conditions (implementation temperature during the foaming sufficiently / higher) allowing at least partial opening of the cell walls. The nature of the cells of the foams obtained can, for example, influence their properties. Indeed, closed cell foams may for example be rigid and / or less flexible / flexible and / or less compressible.

When using a mixture of an ethylene-based polymer rich in ethylene on the one hand and polybutene-1 (homopolymer of butene-1) on the other hand, a phase separation due to incompatibility between the ethylene or polyethylene-rich phase and the polybutene-1 or polybutene-1-rich phase. Moreover, the foams obtained in this case have poor mechanical properties. Indeed, the mixture, which comprises nodules / nuclei of polybutene-1 or rich polybutene-1 dispersed in a polyethylene phase or rich in polyethylene, is weakened because the interface between the polybutene-1 nodules or rich in polybutene-1 and the polyethylene or the polyethylene-rich phase is fragile. Cracks propagate easily between and especially at the interfaces between polybutene-1 or polybutene-1-rich nodules and polyethylene or the polyethylene-rich phase. The incompatibility between polybutene-1 and polyethylene therefore leads to poor mechanical properties.

A phase rich in polyethylene may for example be a phase comprising for example at least 50%, preferably at least 51%, preferably at least 55%, preferably at least 60%, preferably at least 65%, preferably at least 55%, preferably at least 70%, preferably at least 75%, preferably at least 80%, preferably at least 85%, preferably at least 90%, preferably at least 95%, preferably at least 97%, preferably at least 98%, preferably at least 99%, preferably at least 99.5%, preferably at least 99.9%, preferably at least 99.99%, preferably at least 99.999% by weight, of polyethylene and / or ethylene. A phase and / or a nodule / nuclei rich in polybutene-1 may mean for example a phase and / or a nodule / nuclei comprising for example at least 50%, preferably at least 51%, preferably at least 55%, preferably at least 60%, preferably at least 65%, preferably at least 70%, preferably at least 75%, preferably at least 80%, preferably at least 85%, preferably at least 90%, preferably preferably at least 95%, preferably at least 97%, preferably at least 98%, preferably at least 99%, preferably at least 99.5%, preferably at least 99.9%, preferably at least 99.99%, preferably at least 99%. at least 99.999% by weight of polybutene-1 and / or butene-1.

In addition, the use of a butene-based polymer rich in butene-1, whose melting point is, for example, less than 135 ° C., and / or particularly a copolymer of butene-1 and of another α-olefin, such as ethylene, rich in butene-1, instead of polybutene-1 (homopolymer of butene-1), does not seem to significantly improve the dispersion of the polybutene-1 phase or rich in polybutene-1 in the polyethylene phase or rich in polyethylene. Indeed, the use of a butene-based polymer rich in butene-1, whose melting temperature is for example less than 135 ° C, and / or particularly a copolymer of butene-1 and of another α-olefin, such as ethylene, rich in butene-1, but nevertheless including another α-olefin, such as for example ethylene (which could potentially play a role of accounting), does not improve not the accounting and dispersion of the polybutene-1 or polybutene-1-rich phase in the polyethylene or polyethylene-rich phase. The size of the nodules of the polybutene-1 or polybutene-1-rich phase hardly changes (does not decrease significantly, but remains similar, see Figure 1 and 2). The level of α-olefin and / or, for example, ethylene, of a butene-based polymer rich in butene-1, whose melting temperature is, for example, less than 135 ° C., and / or particularly of a copolymer of butene-1 and another α-olefin, such as for example ethylene, rich in butene-1, does not therefore seem sufficient to improve the dispersion of the polybutene-1 or polybutene-rich phase. 1 and / or to improve the accounting of the polybutene-1 or polybutene-1-rich phase and the polyethylene or polyethylene-rich phase and / or to play the role of accounting between the two phases, particularly at the interface between them.

However, the use of a butene-based polymer rich in butene-1, whose melting point is, for example, less than 135 ° C., and / or particularly a butene-1 copolymer and a Another α-olefin, such as ethylene, rich in butene-1, nevertheless makes it possible surprisingly to obtain foams having good mechanical properties. Indeed, there is no deterioration of foams in case of mechanical stress and particularly in case of repeated mechanical stress. The formation of cracks / cracks is not observed. This may be due for example to a lower degree of crystallinity for a butene-based polymer rich in butene-1, whose melting point is, for example, less than 135 ° C., and / or particularly for a butene-butene copolymer. 1 and another α-olefin, such as ethylene, rich in butene-1, which causes a lower degree of crystallinity in the polybutene-1 or polybutene-1-rich nodules dispersed in the polyethylene or in a phase rich in polyethylene. A lower crystallinity of the polybutene-1 or polybutene-1-rich nodules dispersed in the polyethylene or in a polyethylene-rich phase may, for example, lead to a more amorphous and / or predominantly amorphous interface between the two phases. This may possibly allow for example to promote and / or improve the interpenetration of the two phases at the interface between them, so that the interface between the two phases can be enhanced.

The present invention also relates to a foaming process for obtaining foams based on ethylene and butene according to the present invention, wherein at least one ethylene-rich and ethylene-rich polymer and at least one polymer based on of butene and rich in butene-1, the melting temperature of the latter being less than 135 ° C., are foamed with the aid of at least one foaming agent.

In the foaming process according to the invention, the foaming and / or the extrusion can for example be carried out with an operating temperature during foaming and / or extrusion of less than 150 ° C. preferably less than 145 ° C, preferably less than 140 ° C, preferably less than 135 ° C, preferably less than 132.5 ° C, preferably less than 130 ° C, preferably less than 127.5 ° C, preferably less than 126 ° C, preferably less than 125 ° C, preferably less than 122.5 ° C, preferably less than 120 ° C, preferably less than 117.5 ° C, preferably less than 116 ° C, preferably below 115 ° C, preferably below 114.5 ° C, preferably below 114 ° C, preferably below 113.5 ° C, preferably below 113 ° C, preferably below 112.5 ° C, preferably below less than 112 ° C, meadow less than 111.5 ° C, preferably less than 111 ° C, preferably less than 110.5 ° C, preferably less than 110 ° C, preferably less than 109.5 ° C, preferably less than 109 ° C. The implementation temperature during foaming may preferably, for example, correspond to the maximum die mass temperature during extrusion and / or foaming.

In the foaming process according to the invention, the operating temperature during foaming and / or extrusion (which may for example correspond to the maximum die mass temperature) may for example be between 40 ° C. and 150 ° C, preferably 50 ° C and 140 ° C, preferably between 90 ° C and 130 ° C, preferably between 100 ° C and 120 ° C, preferably between 102 ° C and 117.5 ° C, preferably between 105 ° C and 116 ° C, preferably between 106 ° C and 115.5 ° C, preferably between 107 ° C and 115 ° C, preferably between 107.5 ° C and 114.5 ° C, preferably between 108 ° C and 114 ° C.

Too high or too low a temperature during foaming and / or extrusion may for example result in uncontrolled and / or inefficient and / or inhomogeneous foaming. Under these conditions, it may even be difficult, if not impossible, to obtain for example a relatively homogeneous foam and / or a foam having a certain dimensional stability and / or a foam having particular well-defined properties. Moreover, it can for example also become very difficult under these conditions to obtain and / or vary the desired properties. Indeed, the implementation temperature during foaming and / or extrusion is for example an important parameter, which can control the foaming. A control of the implementation temperature during foaming and / or extrusion thus makes it possible, if necessary, to obtain homogeneous foams and / or foams having a certain dimensional stability and / or foams having properties specific and well defined.

The experiments carried out in the context of the present invention have made it possible to determine that, in the foaming process according to the invention, the processing temperature during foaming and / or extrusion (which may preferably for example correspond, for example) at the die mass temperature) may for example correspond to or be greater than the glass transition temperature or the softening point or the temperature corresponding to the beginning of the melting peak (determined by DSC) or preferably at the temperature of melting of the ethylene-based polymer and / or the butene-based polymer rich in butene-1. A temperature may be, for example, the glass transition temperature or the softening point or the temperature corresponding to the beginning of the melting peak (determined by DSC) or the melting point of the ethylene-rich and ethylene-rich polymer. and / or butene-based polymer rich in butene-1, if it is equal to said temperature plus or minus 50 ° C, preferably plus or minus 40 ° C, preferably plus or minus 30 ° C, preferably plus or minus 25 ° C, preferably plus or minus 22.5 ° C, preferably plus or minus 20 ° C, preferably plus or minus 17.5 ° C, preferably plus or minus 15 ° C, more preferably or at least 14 ° C, preferably plus or minus 13 ° C, preferably plus or minus 12 ° C, preferably plus or minus 11 ° C, preferably plus or minus 10 ° C, preferably plus or minus 9 ° C preferably more or less 8 ° C, preferably plus or minus 7 ° C, preferably more or less 6 ° C, preferably plus or minus 5 ° C, preferably plus or minus 4 ° C, preferably plus or minus 3 ° C, preferably plus or minus 2 ° C, preferably plus or minus 1 ° C C, preferably plus or minus 0.75 ° C, preferably plus or minus 0.5 ° C, preferably plus or minus 0.1 ° C, preferably plus or minus 0.01 ° C or preferably more or less 0.001 ° C.

The experiments carried out in the context of the present invention have made it possible to determine that, in the foaming process according to the invention, the processing temperature during foaming and / or extrusion (which may preferably for example correspond, for example) at maximum die temperature) may, for example, be within plus or minus 50 ° C, preferably at plus or minus 40 ° C, preferably at plus or minus 30 ° C, preferably at plus or minus 25 ° C, preferably at plus or minus 22.5 ° C, preferably at plus or minus 20 ° C, preferably at plus or minus 17.5 ° C, preferably at +/- 15 ° C, preferably at plus or minus 14 ° C, preferably at plus or minus 13 ° C, preferably at plus or minus 12 ° C, preferably at plus or minus 11 ° C, preferably at more or less 10 ° C, preferably at plus or minus 9 ° C, meadow preferably at most +/- 7 ° C, preferably at plus or minus 6 ° C, preferably at plus or minus 5 ° C, preferably at plus or minus 4 ° C. ° C near, preferably to plus or minus 3 ° C, preferably to plus or minus 2 ° C near or preferably to plus or minus 1 ° C near the melting temperature of the ethylene-based polymer and / or butene-based polymer rich in butene-1. This allows a good mix of polymers and effective foaming.

On the other hand, the experiments carried out in the context of the present invention have also made it possible to determine that, in the foaming process according to the invention, the temperature of implementation during foaming and / or extrusion (which can for example preferably correspond to the temperature in the form of a spinneret) may for example preferably be less than 150 ° C. This makes it possible, for example, to retain good control of the foaming. Indeed, beyond this temperature control foaming seems difficult and foaming seems ineffective. The products obtained may for example tend to collapse instead of forming a foam having good dimensional stability.

The foaming agent (s) used in the foaming process according to the invention may (for example) comprise at least one chemical foaming agent and / or at least one physical foaming agent. A chemical foaming agent may for example comprise at least one compound or a mixture of compounds, which can release at least one gas (such as for example nitrogen or CO2). A chemical foaming agent may for example comprise azodicarbonamide, azodiisobutyronitrile, benzol-sulphonylhydrazide, 4,4-oxybenzolsulfonylsemicarbazide, 4,4-oxybis (benzolsulfonylhydrazid), diphenylsulfon-3,3-disulfonyl- hydrazide, p-toluolsulfonylsemicarbazide, N, N-dimethyl-N, N-dinitrosoterephthalamide, trihydrazintriazine, N = N-dinitrosopentamethylenetetramine, dinitrosotrimethyltriamine, sodium hydrogencarbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, potassium carbonate, diazobenzene, diazotoluene, hydrazodicarbonamide, diazoisobutyronitrile, barium carboxylate, 5-hydroxytetrazole and / or at least one derivative and / or mixture of at least two of these compounds.

A physical foaming agent used in the foaming process according to the invention may for example comprise at least one gas or at least one liquid, which may preferably be volatile. A physical foaming agent may for example comprise carbon dioxide, nitrogen, argon, water, air, helium, aliphatic hydrocarbons with 1 to 6 carbon atoms, aliphatic alcohols with 1 to 3 carbon atoms, fully or partially halogenated aliphatic hydrocarbons with 1 to 4 carbon atoms, methane, ethane, propane, n-butane, isobutane, n-butane; pentane, isopentane, neopentane, hexane, isohexane, heptane, octane, methylpentane, dimethylpentane, butene, pentene, 4-methylpentene, hexene, 2,2-dimethylbutane, petroleum ether, methanol, ethanol, n-propanol, isopropanol, fully or partially chlorinated and / or fluorinated aliphatic hydrocarbons, trichlorofluoromethane, trichloromethane, tetrachloromethane, chlorofluoromethane, methyl chloride, methylene chloride, ethyl chloride e, ethylene chloride, 1,1,1-trichloroethane, 1,1,1-trifluoroethane, dimethyl ether and / or at least one derivative of at least one of these compounds and / or a mixture of at least two of these compounds.

In the foaming process according to the invention and in order to obtain foams according to the invention, the foaming can for example take place by mechanical means, such as, for example, a reactor and / or a mixer and / or an extruder. In addition, the foaming agent may for example be added to the ethylene-rich polymer and the butene-butene-1-rich polymer by mechanical means, such as a reactor and / or a mixer and / or an extruder, in the foaming process according to the invention and to obtain foams according to the invention. In the foaming process according to the invention and to obtain foams according to the invention, the foaming can therefore preferably be carried out for example by extrusion. This can allow for example an easy and effective foaming.

In addition, it is possible to obtain either ethylene and butene based foams herein having open cells and / or closed cells by a foaming method according to the invention, for example depending on the conditions. extrusion and / or foaming. Conditions allowing for example to obtain closed cell foams are given in the examples below. Open cell foams can nevertheless for example be obtained by virtue of temperature conditions (implementation temperature during the foaming enough / higher) allowing at least partial opening of the cell walls. The nature of the cells of the foams obtained can, for example, influence their properties. Indeed, closed cell foams can for example be rigid and / or less flexible / flexible and / or less compressible than open cell foams.

Examples: 1) Dispersion A- Mixture of polyethylene and polybutene-1 made for comparison

For a mixture of an ethylene-rich and ethylene-rich polymer on the one hand and polybutene-1 (homopolymer) on the other hand (70% by weight of LDPE / LDPE, 2601TX17 of SABIC and 30% by weight of polybutene-1, homopolymer PB 110 from LYONDELLBASELL), a phase separation is observed due to the incompatibility between the polyethylene phase or rich in ethylene and the polybutene-1 phase or rich in polybutene-1 (see Figure 1).

Figure 1 is an image of a section of the mixture obtained using an electron microscope. There are small nuclei / nodules of polybutene-1 or polybutene-1-rich dispersed in a polyethylene phase or rich in polyethylene.

Moreover, the foams obtained in this case have poor mechanical properties.

Indeed, the mixture, which comprises nodules of polybutene-1 or rich in polybutene-1 dispersed in a polyethylene phase or rich in polyethylene, is weakened because the interface between the polybutene-1 nodules or polybutene-rich 1 dispersed in a polyethylene phase or rich in polyethylene is fragile.

In case of mechanical stress and particularly in case of repeated mechanical stress, there is a degradation of the foams and their properties, more particularly for example the formation of cracks / cracks.

Cracks propagate easily between and especially at the interfaces between polybutene-1 or polybutene-1-rich nodules and polyethylene or the polyethylene-rich phase.

The incompatibility between polybutene-1 and polyethylene therefore leads to poor mechanical properties.

B-Mixture of an ethylene-rich and ethylene-rich polymer and a butene-based polymer rich in butene-1

For a mixture of a polymer based on ethylene and rich in ethylene on the one hand and butene-based polymer rich in butene-1, whose melting point is for example less than 135 ° C. (for example a copolymer), on the other hand, there is also a phase separation due to incompatibility between the polyethylene rich phase and the rich polybutene-1 phase (see Figure 2). The mixing conditions are identical.

FIG. 2 is an image of a section of a mixture of 70% by weight of LDPE / LDPE, 2601TX17 of SABIC and 30% by weight of a butene-based polymer rich in butene-1, whose melting temperature is, for example, less than 135 ° C., KOATTRO KT AR 05, TfUS = 114 ° C., from LYONDELLBASELL, obtained using an electron microscope (the mixing conditions are identical to the conditions used for the mixing of polyethylene and a butene-1 homopolymer described above). There are small nuclei / nodules of polybutene-1 or polybutene-1-rich dispersed in a polyethylene phase or rich in polyethylene.

The use of a butene-based polymer rich in butene-1, whose melting temperature is, for example, less than 135 ° C., and / or particularly a copolymer of butene-1 and of another olefin, such as ethylene, rich in butene-1, instead of polybutene-1 (homopolymer of butene-1), does not seem to significantly improve the dispersion of the phase of polybutene-1 or rich polybutene-1 in the polyethylene phase or rich in polyethylene.

Indeed, the use of a butene-based polymer rich in butene-1, whose melting temperature is for example less than 135 ° C, and / or particularly a copolymer of butene-1 and of another α-olefin, such as ethylene, rich in butene-1, but nevertheless including another α-olefin, such as for example ethylene (which could potentially play a role of accounting), does not improve however, no accounting and dispersion of the polybutene-1 or polybutene-1-rich phase in the polyethylene or polyethylene-rich phase. The size of the nodules of the polybutene-1 or polybutene-1-rich phase hardly changes (does not decrease significantly, but remains similar, see Figure 1 and 2).

The level of α-olefin and / or, for example, ethylene, of a butene-based polymer rich in butene-1, whose melting temperature is, for example, less than 135 ° C., and / or particularly of a copolymer of butene-1 and another α-olefin, such as ethylene, rich in butene-1, therefore does not seem sufficient to improve the dispersion of the polybutene-1 or polybutene-rich phase. 1 and / or to improve the accounting of the polybutene-1 or polybutene-1-rich phase and the polyethylene or polyethylene-rich phase and / or to play the role of accounting between the two phases, particularly at the interface between them.

However, the use of a butene-based polymer rich in butene-1, whose melting point is, for example, less than 135 ° C., and / or particularly a butene-1 copolymer and a Another α-olefin, such as ethylene, rich in butene-1, nevertheless makes it possible surprisingly to obtain foams having good mechanical properties.

Indeed, there is no deterioration of foams in case of mechanical stress and particularly in case of repeated mechanical stress. The formation of cracks / cracks is not observed.

This may be due for example to a lower degree of crystallinity for a butene-based polymer rich in butene-1, whose melting point is, for example, less than 135 ° C., and / or particularly for a butene-butene copolymer. 1 and another α-olefin, such as ethylene, rich in butene-1, which results in a lower degree of crystallinity in the polybutene-1 nodules or rich in polybutene-1 dispersed in polyethylene or in a phase rich in polyethylene. A lower crystallinity of the polybutene-1 or polybutene-1-rich nodules dispersed in the polyethylene or in a polyethylene-rich phase may, for example, lead to a more amorphous and / or predominantly amorphous interface between the two phases.

This may possibly allow for example to promote and / or improve the interpenetration of the two phases at the interface between them, so that the interface between the two phases can be enhanced.

2) foams based on ethylene and butene according to the invention and obtaining these foams

Foams according to the present invention were prepared with three different compositions (see entries 1, 2 and 3 of Table 1). In addition, for comparison, a PE-BD / LDPE foam was also prepared under similar conditions (see entry 4, Table 1).

Table 1

In addition, each mixture (1,2,3 and 4) further comprises a mixture of several additives: - 3% by weight (relative to the weight of the mixtures of the table) of an additive comprising a mixture of glycerol ester (ATMER 122, CRODA, 70% by weight) and EVA (30% by weight), - 3% by weight (based on the weight of the mixtures of the table) of an additive comprising a mixture of 40% of flake of aluminum in 60% of PE-BD / LDPE, and 2% by weight (based on the weight of the mixtures of the table) of an additive comprising a mixture of 50% by mass of talc in 50% by weight of LDPE / LDPE.

Blends 1, 2, 3 and 4 are extrusion foamed with isobutane using an extruder and using the parameters shown in Table 2.

Table 2

The foaming and / or the extrusion is / are carried out with an operating temperature of between 108.8 ° C. and 110.7 ° C. This temperature is in this case the temperature in a die mass. The maximum die mass temperature is therefore in all cases less than 150 ° C.

For foams based on ethylene and butene based on the present invention (see entries 1 to 3 of Table 1) and for the corresponding foaming process, the implementation temperature corresponds for example to plus or minus 5 ° C to the melting temperature of the ethylene-based polymer and / or the melting temperature of the butene-butene-1-rich polymer.

The foaming is effective and the foams thus obtained for each mixture (1, 2 and 3) have good dimensional stability (no collapse of foams during foaming, nor subsequently at room temperature). The foams obtained are closed cell foams.

In addition, the foams thus obtained for each mixture (1,2 and 3) have good mechanical properties despite the incorporation of a butene-based polymer rich in butene-1.

Indeed, even in the case of mechanical stress and / or stress, no degradation of the foams or their properties is observed (see also the results of the compression tests below). In particular, there is no evidence of crumbling or formation of cracks, cracks, crevices, or other signs of degradation of the foam, even under repeated stress and / or in case of repeated mechanical stress.

Foams thus obtained for each mixture (1,2,3 and 4) were characterized by measuring their density and the number of cells per square centimeter.

Table 3

The foams obtained for each mixture (1,2,3 and 4) were also characterized by measuring their density after a heat treatment at 50 ° C. allowing degassing (see Table 4).

Table 4

It is observed that the density of foams according to the invention comprising a butene-based polymer rich in butene-1 (mixture 1,2 and 3) decreases during degassing (see Table 4).

In addition, the foams according to the present invention obtained for each mixture (1,2 and 3) have excellent flexibility / flexibility (see Table 5 and Figure 3). The flexibility / flexibility of the foams obtained with the mixtures according to the present invention (mixtures 1,2 and 3) is higher than that of a polyethylene foam (mixture 4). Indeed, at equal compression, the flexibility / flexibility of the foams obtained with the mixtures according to the present invention (mixtures 1,2 and 3) comprising a butene-based polymer and rich in butene-1 is higher and the stress is therefore consequently less important (see Table 5 and Figure 3).

It is furthermore noted that the flexibility / flexibility of the foams according to the present invention (mixtures 1, 2 and 3) increases and that the stresses consequently decrease when the content of a butene-based polymer rich in butene-1 increases in the mixture used for foaming (see Table 5 and Figure 3).

Table 5

The relative stress-strain characteristics in compression (see Table 5 and Figure 3) are determined by a compression test by measuring the stress (in N / mm 2) as a function of the compression ratio (in%).

On the other hand, the thermal conductivity of the foams obtained was also measured (see Table 6). Thermal conductivity can give an indication of the thermal insulation properties of foams.

Table 6

It is found that the thermal conductivity of the foams according to the present invention comprising a butene-based polymer rich in butene-1 (mixture 1,2 and 3) is lower than that of a polyethylene foam. The thermal insulation properties of the foams according to the present invention comprising a butene-based polymer rich in butene-1 (mixture 1,2 and 3) are consequently better.

In addition, the thermal conductivity decreases when the butene-based polymer content rich in butene-1 increases. The thermal insulation properties of the foams according to the present invention are thus improved by the addition of a butene-based polymer rich in butene-1 (mixture 1,2 and 3).

Open cell foams can for example be obtained in a similar manner, but using temperature conditions (implementation temperature during the foaming enough / higher) allowing at least partial opening of the cell walls.

Claims (15)

1. Foam based on butene and ethylene, characterized in that it comprises at least one ethylene-based polymer rich in ethylene and at least one butene-based polymer rich in butene-1, the melting temperature of the latter being less than 135 ° C. 2. Foam based on butene and ethylene according to claim 1, characterized in that it comprises at least one ethylene-based polymer rich in ethylene selected from the following group: very low density polyethylene (PE -TBD / VLDPE), linear low density polyethylene (PE-BDL / LLDPE), low density polyethylene (PE-BD / LDPE), medium density polyethylene (PE-MD / MDPE), high-density polyethylene density (PE-HD / HDPE), very low molecular weight polyethylene (ULMWPE), high molecular weight polyethylene (HMWPE). 3. Foam based on butene and ethylene according to one of claims 1 or 2, characterized in that it comprises at least one ethylene-based polymer rich in ethylene, which comprises at least 50% by weight ethylene and / or whose melting temperature determined by DSC is between 30 ° C and 160 ° C and / or whose melt index is between 0.1 and 35 g / 10 min. 4. Foam based on butene and ethylene according to one of the preceding claims, characterized in that it comprises at least one butene-based polymer and rich in butene-1, which comprises at least 50% by weight of butene-1 and / or whose melt index is between 0.4 and 0.6 g / 10 min. 5. Foam based on butene and ethylene according to one of the preceding claims, characterized in that it comprises at least one butene-based polymer and rich in butene-1, which comprises at least 50% by weight of butene-1 and / or whose melt index is between 0.4 and 0.6 g / 10 min. 6. Foam based on butene and ethylene according to one of the preceding claims, characterized in that it comprises at least one butene-based polymer and rich in butene-1, which is a copolymer and / or a copolymer comprising butene-1 and at least one other α-olefin. 7. Foam based on butene and ethylene according to one of the preceding claims, characterized in that it comprises at least one butene-based polymer and rich in butene-1, which is a copolymer comprising butene-1 and ethylene. 8. Foam based on butene and ethylene according to one of the preceding claims, characterized in that it comprises at least one butene-based polymer and rich in butene-1 whose melting temperature determined by DSC is lower at 120 ° C and / or is greater than 60 ° C. 9. Foam based on butene and ethylene according to one of the preceding claims, characterized in that it comprises at least one butene-based polymer and rich in butene-1 and at least one polymer based on ethylene and ethylene-rich selected such that the difference between the DSC-determined melting temperatures of a butene-based / butene-1-rich polymer and an ethylene-based polymer and rich in ethylene on the other hand is less than 40 ° C. 10. Foam based on butene and ethylene according to one of the preceding claims, characterized in that at least one butene-based polymer and rich in butene-1 and at least one ethylene-based polymer and rich ethylene selected such that the difference between the melt flow rate of a butene-based / butene-1-rich polymer and an ethylene-rich / ethylene-based polymer on the other hand is less than 25 g / 10 min or less than 1 g / 10 min. 11. Foam based on butene and ethylene according to one of the preceding claims, characterized in that it comprises at least one additive selected from: at least one additive that improves the insulation properties and particularly thermal insulation , an additive comprising carbon black, carbon nanotubes, fullerenes, flakes / metal particles, aluminum flakes, at least one additive which facilitates the implementation and / or foaming, at least an additive comprising talc, a mixture of talc and polyethylene, a mixture of talc and LDPE, one or more clays, titanium dioxide, silicon dioxide, EVA and / or one or more esters of fatty acid and / or one or more fatty acid amides and / or one or more glycerol esters, one or more stearate (s), barium stearate, sodium stearate, glycerol stearate and / or glycerol alpha-monostearate, at least one stabilizer, at least a UV absorber, at least one plasticizer and / or at least one flame retardant and / or at least one derivative of at least one of these compounds / additives and / or a mixture of at least two of these compounds / additives. 12. A foaming process for obtaining foams based on ethylene and butene, characterized in that at least one ethylene-rich and ethylene-rich polymer and at least one butene-based and high-molecular-weight polymer. butene-1, the melting temperature of the latter being less than 135 ° C, are foamed with at least one foaming agent. 13. A foaming process for obtaining foams based on ethylene and butene according to claim 12, characterized in that the foaming can be carried out (e) with a temperature of implementation during the foaming and / or the extrusion of less than 150 ° C. 14. A foaming process for obtaining foams based on ethylene and butene according to one of claims 12 or 13, characterized in that the foaming can be carried out (e) with a processing temperature during foaming and or extrusion which may correspond to or be greater than the glass transition temperature or the softening point or the temperature corresponding to the beginning of the melting peak (determined by DSC) or the melting point of the polymer to ethylene base and rich in ethylene and / or butene-based polymer rich in butene-1. 15. A foaming process for obtaining foams based on ethylene and butene according to one of claims 12 to 14, characterized in that the foaming is carried out using at least one physical foaming agent and / or chemical selected from: at least one compound or a mixture of compounds, which may release at least one gas, azodicarbonamide, azodiisobutyronitrile, benzolsulfonylhydrazide, 4,4-oxybenzolsulfonylsemicarbazide, 4,4-oxybis ( benzolsulfonylhydrazid), diphenylsulfon-3,3-disulfonyl hydrazide, p-toluolsulfonylsemicarbazide, N, N-dimethyl-N, N-dinitrosoterephthalamide, trihydrazintriazine, N = N-dinitrosopentamethylenetetramine, dinitrosotrimethyltriamine, sodium hydrogencarbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, potassium carbonate, diazobenzene, diazotoluene, hydrazodicarbonamide, diazoisobutyronitrile, barium carboxylate, 5- hyd roxytetrazole, at least one gas or at least one liquid, which may preferably be volatile, carbon dioxide, nitrogen, argon, water, air, helium, aliphatic hydrocarbons with 1 to 6 carbon atoms, aliphatic alcohols with 1 to 3 carbon atoms, fully or partially halogenated aliphatic hydrocarbons with 1 to 4 carbon atoms, methane, ethane, propane, n butane, isobutane, n-pentane, isopentane, neopentane, hexane, isohexane, heptane, octane, methylpentane, dimethylpentane, butene, pentene, 4-methylpentene, hexene, 2,2-dimethylbutane, petroleum ether, methanol, ethanol, n-propanol, isopropanol, aliphatic hydrocarbons totally or partially chlorinated and / or fluorinated, trichlorofluoromethane, trichloromethane, tetrachloromethane, chlorofluoromethane, methyl chloride, chlorine methylene chloride, ethyl chloride, ethylene chloride, 1,1,1-trichloroethane, 1,1,1-trifluoroethane, dimethyl ether and / or at least one derivative of at least one of these compounds and / or a mixture of at least two of these compounds