BE1024635B1 - OPEN CELL FOAMS OF POLYOLEFINEN - Google Patents

Abstract

This invention relates to polyolefin based foams comprising a blend of (a) at least one first ethylene polymer made from ethylene homopolymers made by a high pressure process and polar ethylene copolymers produced by a high pressure process, is selected; (b) at least one thermoplastic elastomer having styrene blocks or at least one thermoplastic elastomer containing a crosslinked silicone type elastomer phase; (c) at least one second ethylene polymer which is different from the one or more ethylene polymers of component (a) and which has a melting point which is at least 5 ° C lower than the first ethylene polymer of component (a) having the lowest melting point, wherein the at least one second ethylene polymer is made of polar ethylene copolymers prepared by a high pressure process; Metallocene polyethylenes or combinations thereof is selected; wherein the at least one second ethylene polymer functions as a cell opening agent; and (d) comprise at least one ionomer.

Description

INVENTION PATENT économie

FPS Economy, K.M.B., SMEs and Energy

Intellectual Property Office

1024635 sheets

Date of issue: 14/05/2018

Priority date:

International classification: C08J 9/00, C08L 23/04

Registration number: BE2016 / 5739

Registration date: 05/10/2016

Owner:

NMC S.A.

4731, EYNATTEN Belgium

Inventor:

SCHÖPGES Florence 4831 BILSTAIN Belgium

JOB Denis

4031ANGLEUR

Belgium

MAYERES Jean-Pierre 4700 EUPEN Belgium

OPEN-CELLED FOAMS MADE OF POLYOLEFINES

The invention relates to foams based on polyolefins, which are a mixture of (a) at least one first ethylene polymer, which consist of ethylene homopolymers which have been produced by a high pressure process, and polar ethylene copolymers which have been produced by a high pressure process, is selected; (b) at least one thermoplastic elastomer with styrene blocks or at least one thermoplastic elastomer containing an elastomer phase of the cross-linked silicone type; (c) at least one second ethylene polymer which is different from the ethylene polymer (s) of component (a) and which has a melting point which is at least 5 ° C. lower than the first ethylene polymer of component (a) which has the lowest melting point, the at least one second ethylene polymer made of polar ethylene copolymers produced by a high pressure process; Metallocene polyethylene or combinations thereof is selected; wherein the at least one second ethylene polymer acts as a cell opening agent; and (d) comprise at least one ionomer.

BELGIAN INVENTION PATENT

FÖD Wirtschaft, K.M.B., Mittelstand & publication number: 1024635 Energy filing number: BE2016 / 5739

Office of Intellectual Property Boarding. Classification: C08J 9/00 C08L 23/04

Date of issue: 14/05/2018

The Minister for Enterprise

Due to the Paris Treaty of March 20, 1883 for the protection of industrial property;

Introduced under the Act of March 28, 1984 on Inventive Patents, Article 22, for inquiries prior to September 22, 2014;

Based on Title I “Invention Patents” of Book XI of the Economic Code, Article XI.24, introduced for inquiries from September 22, 2014;

Based on the royal decree of December 2, 1986 on the registration, granting and maintenance of patents for invention, Article 28;

Recorded on 05/10/2016 at the Intellectual Property Office based on the protocol.

Considering that for patent applications that fall within the scope of Title 1, Book XI, of the Economic Code, in accordance with Article XI.19, Section 4, second paragraph, of the Economic Code, if the patent application is the subject of a search report in which a lack of unity of invention within the meaning of paragraph 1 is mentioned, and if the applicant does not limit his application and does not file a divisional application in accordance with the search report, the granted patent will be limited to the claims for which the search report was created.

DECIDES:

Article 1. - An invention patent is granted to:

NMC S.A., Gert-Noël-Strasse, 4731 EYNATTEN Belgium;

represented by :

OFFICE FREYLINGER S.A., Route d'Arlon 234 P.O. Box 48, 8001, STREETS;

for a period of 20 years, subject to the payment of the annual patent fees mentioned in Article XI.48, §1 of the Economic Code, for: OPEN-CELLED FOAMS FROM POLYOLEFINES.

INVENTOR:

SCHÖPGES Florence, Grand Bosi 3, 4831, BILSTAIN;

JOB Denis, Rue Vaudrée 12, 4031, ANGLEUR;

MAYERES Jean-Pierre, Lindenweg 11, 4700, EUPEN;

PRIORITIES) :

SEPARATION:

Partial application of the previous application: Date of filing of the previous application:

Article 2. - This patent is granted without any prior examination of the patentability of the invention, without guaranteeing the merit of the invention or the accuracy of its description, and at the own risk of the patent applicant (s).

Brussels, 14/05/2018, in special representation:

BE2016 / 5739

P-NMC-046 / BE2

OPEN-CELLED FOAMS MADE OF POLYOLEFINES

Technical field

The present invention relates to soft open-cell foams made from polyolefins, a process for producing such foams and the resulting products.

State of the art

Open-line polyolefin foams are interesting for obtaining a product that is softer than the corresponding quality with predominantly closed cells. There are several known methods for opening the cells of a foam, of which the following can be named:

a) extrusion of a closed-cell foam, then squeezing the foam to break apart the cell walls and to allow a connection for the gas of the cells between them: this requires an extra step for extrusion, which must be done offline depending on the case; furthermore, the amount of cells actually open will depend on the intensity and duration of the squeezing, and if the polymer composition is particularly elastic, the proportion of open cells will be lower than expected;

b) extrusion of a closed-cell foam, then piercing into the foam with needles, more or less deep and dense (needles per surface unit), in order to perforate the cell walls: additional work step after the extrusion, depending on the case, online or offline; several

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Plunge runs may be required to achieve the desired flexibility;

c) extrusion of a foam comprising a polyolefin type at a temperature higher than that which results in a foam with predominantly closed cells from this composition. The viscosity of the cell walls is lower because the extrusion temperature on the die is deliberately higher, the difficulty being the setting of this temperature (narrow window available) so that the foam does not collapse immediately after exiting the extrusion die. It is then necessary to solidify a certain depth of the surface of the foam by means of active cooling (inflated air, water jet, etc.), which gives sufficient rigidity to maintain the shape of the rest of the core of the foam and to limit its collapse. No online or offline work step is required to obtain the desired foam quality.

d) extrusion of a foam comprising a type of polyolefin and another polymer that is not a polyolefin. The incompatibility between these two types of polymer favors the breakage of the cell walls. A known example of this technique is given by US4384032 and WO 2006024658 (in this latter document a step of squeezing the foam is required: "mechanical opening of the cells").

e) Extrusion of a foam comprising a polyolefin with a melting temperature T1 and a polyolefin with a melting temperature T2 <T1, at a temperature higher than that which results in a foam with predominantly closed cells from this composition. The field of action for the extrusion temperature is enlarged compared to the previous method c) thanks to the difference between the melting points of the two polyolefins. It is also useful here to actively cool the surface of the foam immediately after

BE2016 / 5739 to exit the extrusion nozzle so that the foam does not collapse. No online or offline work step is required to obtain the desired foam quality. An example of this prior art is described in EP 405103.

f) Methods c) and e) may comprise mixtures using two polar polyethylene copolymers with different melting points and either a chloropolyethylene type polymer (EP1594919B1) or a metallocene polyethylene (EP1594918B1) to give the flexibility of the resulting To further increase foams.

A limitation of foams of the prior art e) is the temperature resistance of the foam, since the polyethylene copolymers selected as the starting material are less crystalline than an ethylene homopolymer such as LDPE. In addition, the compositions that use chlorinated polyethylene (CPE) have more intense nucleation (= generation of cells of the foam) due to the presence of additives that are required to produce the CPE. These additives reduce the size of the cells in favor of the flexibility of the foam, but to the detriment of the scope for obtaining foams with a larger cell size or the addition of other functional additives, such as flame retardants, if these themselves have a pronounced nucleating ability. Certain pigments or additives also have a not negligible nucleating capacity; the use of CPE can thus prevent the desired dosage of these other additives from being achieved.

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Subject of the invention

An object of the present invention is consequently to provide different foam compositions which enable the production of open-line foams with a good softness which are not or at least to a lesser extent susceptible to the disadvantages mentioned above.

General description of the invention

To solve the above-mentioned problem, the present invention provides, in a first aspect, a foam based on polyolefins, which comprises a mixture of the following components:

(a) at least a first ethylene polymer made from ethylene homopolymers (or polyethylene homopolymers) made by a high pressure process and polar ethylene copolymers (also referred to as "first" polar ethylene copolymers, as opposed to those of component (c )) made by a high pressure process (e.g. EVA, EBA, EMA, etc.), or a combination of the two;

(b) at least one thermoplastic elastomer with styrene blocks (TPE-S or TPS) or a thermoplastic elastomer containing a cross-linked silicone type elastomer phase;

(c) at least one second ethylene polymer which differs from the ethylene polymer (s) of component (a) and which has a melting point which is at least 5 ° C. lower than the first ethylene polymer of component (a) , which has the lowest melting point, the at least one second ethylene polymer consisting of polar ethylene copolymers (also referred to as “second” polar ethylene copolymers, in contrast to those of component (a)), which were produced by a high-pressure process (for example EVA , EBA, EMA, etc.); Metallocene polyethylene or their

B E2016 / 5739

Combinations is selected; wherein the at least one second ethylene polymer acts as a cell opening agent; and (d) at least one ionomer.

In another aspect, the invention relates to the use of a foam, such as that described in this document, for the production of seals, liquid absorption foams, filters,

Sound absorption elements etc.

Accordingly, in an additional aspect, the present invention particularly relates to seals, liquid absorption foams, filters, and sound absorption elements comprising a foam as described herein.

In yet another aspect, the invention relates to a method of making a foam as described herein, the method comprising the following steps:

(i) Dosing components (a) to (d) and possibly other components as described in this document, in particular other polymers, such as metallocene polyethylene, which none

Has a melting point which is at least 5 ° C lower than that of component (a), which has the lowest melting point, or ordinary additives or auxiliaries, premixed or individually metered, for feeding an extruder;

(ii) plasticizing and mixing the components at a high temperature to melt and homogenize the components;

(iii) injecting a foaming gas;

(iv) homogenizing the components and the gas;

(v) cooling the mass;

BE2016 / 5739 (vi) extruding through a temperature controlled die with a section of a predefined shape in the open air causing the foam to form;

(vii) cooling the foam thus formed, optionally in an active manner after exiting the nozzle, optionally by pulling and guiding the foam thus formed.

The foams according to the different embodiments of the invention described here have several advantages, both in terms of production and in relation to the foams themselves and their applications.

In fact, surprisingly, when combining thermoplastic elastomers and ionomers with ethylene homopolymers and polar copolymers, as described herein, it has been found that it is possible to produce very soft open-cell foams with a quality that is at least equivalent to that of known foams. In general, it is even possible to achieve lower densities or larger cell sizes than before, and this with a more easily controllable process, especially with regard to controlling the temperature with respect to the extrusion die. Indeed, the usable temperature range, i.e. H. the temperature range at which it is possible to produce a homogeneous foam without holes with a regular external appearance, significantly larger than in certain known processes (see below), generally by at least one degree Celsius, often more. Since the regulation is generally made close to a tenth or a few tenths of a degree, the extrusion results are very reproducible, be it in terms of the external appearance, the proportion of open cells or the density. The foams can also be produced with very conventional equipment without any special modification. In contrast to certain other known methods, no additional online or offline intervention is required to achieve the desired one

BE2016 / 5739

Degree of softness (which depends in particular on the density and the proportion of open cells). In addition, there are significantly fewer restrictions with regard to any additives and auxiliaries (and their amounts) than in certain known processes. Finally, the foams according to the invention have a rapid restoration of their original dimensions after compression and then relaxation of the load.

The foams according to the invention are preferably foams which comprise a high proportion of open cells, generally more than 50%, preferably more than 60%, even more preferably more than 70% and particularly preferably more than 80%. The proportion of open cells can be varied by controlling the temperature of the mass at the outlet of the extrusion die, the nozzle, in step (vi) (in conjunction with the cooling of step (v)). The proportion of open cells for the flexible foams can be determined, for example, according to the following measurement method:

Cutting pieces of foam perpendicular to the extrusion direction in lengths of 2, 4, 6 and 8 cm, weighing each piece;

- immersing the pieces in a solution of 95% water and 5% polyalkylene glycol for 10 minutes in a sealed container connected to a vacuum pump which is set to a negative pressure of ± 460 mbar;

- Remove the pieces and immerse in methanol for 2-3 seconds;

Placing the pieces in an oven at 60 ° C for 5 minutes;

- Removing the pieces and then possibly wiping the surfaces that still have traces of liquid on the outside of the foam;

- Weighing the pieces.

The difference in weight represents the amount of water absorbed by the porosity of the foam. By converting this weight to volume

BE2016 / 5739, knowing the density of the foam before weighing and its weight, therefore gives the volume of the foam and from it the volume percentage of the liquid absorbed.

Polyethylene homopolymer or ethylene homopolymer in connection with component (a) means polymers which have been produced under high pressure and are based on ethylene, in particular low-density polyethylene (LDPE), which preferably has a melt flow index (“melt flow index”) , MFI [190 ° C - 2.16 kg]) from 0.1 to 25, more preferably from 0.25 to 15, very particularly preferably 0.5 to 8 g / 10 min

The polar ethylene copolymers which were produced by a high-pressure process of component (a) are in particular ethylene / ethyl acrylate copolymers (EEA copolymers), ethylene / vinyl acetate copolymers (EVA copolymers), ethylene butyl acrylate copolymers (EBA copolymers) and ethylene methyl acrylate copolymers (EMA copolymers) ). The melt index [190 ° C. - 2.16 kg] of these copolymers can vary from 0.1 to 25, preferably from 0.7 to 15, very particularly preferably from 0.5 to 8 g / 10 min. The polar ethylene copolymers produced by a high pressure process, component (c), which are referred to as second polar copolymers to distinguish them from component (a), may a priori be of the same type as the latter, however, have a melting point that is at least 5 ° C lower than that of component (a) which has the lowest melting point (wherein component (a) consists of a polar ethylene homopolymer or a polar ethylene copolymer or a mixture of several of these ). EVA, EBA and EMA are preferably used as polar ethylene copolymers, especially in component (c).

Component (b) comprises at least one thermoplastic elastomer with styrene blocks (TPE-S or TPS), in particular a styrene-butadiene-styrene copolymer (SBS copolymer, such as KRATON D 1101), a styrene-ethylene-butylene-styrene copolymer (SEBS copolymer) such as KRATON G 1652), a polystyrene bB E2016 / 5739

Polyisoprene-b-polystyrene copolymer (SIS copolymer), a polystyrene-b-poly (ethylene propylene) -b-polystyrene copolymer (SEPS copolymer), a polystyrene-b-poly (ethylene ethylene / propylene) -b polystyrene copolymer (SEEPS copolymer) and their functionalized variants, which include polar groups along the central elastomer block; or a thermoplastic elastomer which contains a crosslinked silicone-type elastomer phase, in particular mixtures of a thermoplastic (polyolefin, polyurethane, polyester, etc.) with a crosslinked silicone rubber phase, see patent US6479580B1, preferably TPSiV.

Components (a), (b) and (c) each preferably make up 5 to 85% by weight of the total composition. Component (a) is preferably from 5% by weight to 80% by weight, more preferably from 10% by weight to 70% by weight, particularly preferably from 20% by weight to 60% by weight of the overall composition. Component (b) is preferably from 5% by weight to 80% by weight, more preferably from 10% by weight to 70% by weight, particularly preferably from 20% by weight to 60% by weight of the

Overall composition. Component (c) is preferably from 5% by weight to 80% by weight, more preferably from 10% by weight to 70% by weight, particularly preferably from 20% by weight to 60% by weight of the

Overall composition.

The ionomer or ionomers are preferably selected from the group of polymers comprising acid groups which are at least partially neutralized by monovalent or divalent counterions. In particularly preferred variants, the copolymers are ethylene-methacrylic acid. The percentage of acid groups (i.e. acid group monomers relative to the other monomers of the ionomer polymer) may also vary, but is preferably between 5 and 30%. The monovalent or divalent counterions are preferably sodium,

Lithium, calcium, magnesium and / or zinc selected; however, other counterions can also be useful. The degree of neutralization of the acid groups

B E2016 / 5739 can vary depending on the components used and the desired degree of softness; preferably the

Degree of neutralization lower than 80%. In certain cases, the amount of counterions can be higher or even in relation to the stoichiometry in the

There is excess, d. H. the degree of neutralization can exceed 100%.

The ionomer or ionomers make up 0.1 to 85% by weight of the total composition, preferably 0.5 to 70% by weight and even more preferably 0.75 to 50% by weight, particularly preferably 1 to 30% by weight. %, in particular 1.5 to 20% by weight or even 2 to 10% by weight. Particularly suitable ionomers are the ionomers SURLYN 1705-1, SURLYN 1652,

SURLYN 9520 or SURLYN 9650, although others can also be useful, such as SURLYN 1707, SURLYN 1901, SURLYN 9721, SURLYN 7940 or SURLYN 9945.

In certain variations, the foams may also include one or more additional metallocene polyethylenes that do not have a melting point that is at least 5 ° C lower than that of component (a), which has the lowest melting point, i. H. Metallocene polyethylenes which differ from those which can be used as or in component (c), preferably in an amount of 1 to 50% by weight, based on the total composition.

The so-called metallocene polyethylenes (mPE or PE-MC) are homopolymers which are obtained by a catalytic process with metallocenes (and consequently by a process which is different from the high-pressure process which is carried out by radical polymerization) and have little or no branching from include long type. Furthermore, the mPE generally have a relatively narrow molecular weight distribution. In general, suitable metallocene polyethylenes have a density of less than 925 kg / m ³ , preferably less than 920 kg / m ³ .

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According to a variant of the invention, the metallocene polyethylenes which can be used in or as component (c) have a melting point which is at least 5 ° C. lower than that of component (a) which has the lowest melting point . Regardless of whether or not component (c) comprises the metallocene polyethylenes which have a melting point which is at least 5 ° C. lower than that of component (a) which has the lowest melting point, the foams can do so additional metallocene polyethylenes, provided that their melting point is not at least 5 ° C lower than that of component (a), which has the lowest melting point. In practice, the additional metallocene polyethylene (s) may have a melting point that is greater than or equal to that of component (a), which has the lowest melting point. The melting point of the optional additional metallocene polyethylene (s) may be even greater than that of any of the polymers that form component (a).

The foams according to the invention can contain other components, in particular ordinary additives and auxiliaries, for example from the group comprising nucleating agents, de-nucleating agents, agents for controlling dimensional stability, antistatic agents, pigments, antioxidants, UV protection agents, lubricants, flame retardants and infrared reflecting / absorbing pigments and Crystallization means (means to accelerate the crystallization) are selected.

In order to regulate the cell structure advantageously, nucleating agents can therefore be used. "Passive" nucleating agents can be used, such as talc, calcium carbonate, silicon dioxide or calcium stearate. Preferably "active" nucleating agents can be used, such as the combinations of sodium hydrogen carbonate and / or citric acid that are commercially available ("HYDROCEROL" from CLARIANT, "SAFOAM" from REEDY, "TRACEL" from TRAMACO etc. and related products) release the gas by exposure to temperature

BE2016 / 5739 is decomposed during the process, which enables a particularly fine and regular cell structure to be obtained on the entire section of the foam. These "active" agents are available in the form of masterbatches based on the appropriate resin (polyethylene, ethylene copolymer, metallocene polyethylene, etc.). Preferably, the "passive" nucleating agents, such as those mentioned above, and "active" nucleating agents are used together to optimize cell structure and formulation costs, with the "active" nucleating agents generally being more expensive than the "passive" nucleating agents. The dosage of these nucleating agents is adjusted according to the desired cell structure. For example, 0.1 to 10% by weight of active nucleating agents are used, the passive nucleating agents defined above being included or not.

Agents that improve processability can also be added: fluoroelastomers, polyolefin waxes, silicone copolymers, etc.

Additives can be added which make it possible to enlarge the size of cells of the foam, such as oxidized polyolefin waxes, polar paraffins, etc.

The gases which can be used for foaming by direct gasification are known to the person skilled in the art; they are generally volatile organic compounds that have a boiling point (at 1 atmosphere) that is lower than the melting point of the base resin. For example, alkane hydrocarbons, CO ₂ , atmospheric gases (N ₂ , Ar, etc.). Of these products, alkanes are the preferred physical blowing agents, especially C3 and C ₄ alkanes. Isobutane is particularly preferably used.

During production, the extruded foam is preferably guided, practically without tension, through an extrusion press into a cooling section (air

B E2016 / 5739 or water or both) between the nozzle and the extruder to solidify the desired structure.

The extruder can be any suitable extruder, in particular a single-screw extruder or a co-rotating or counter-rotating twin-screw extruder.

It is possible to make foams from the compositions of the present invention in several shapes: round or square profiles, concave or convex irregular shapes, solid or hollow bodies, etc.

It is sufficient to extrude the mixture of polymers + gas through a nozzle with the design and shape required to give the desired expanded final shape.

For hollow forms, a nozzle needle and a nozzle can be used to implement the hollow body, the mixture of polymer + gas (optionally by air or by an adequate coolant) in the molten state flowing around the nozzle needle to solidify as soon as it is on the free air is by cooling it.

Other peculiarities and features of the invention will become apparent from the detailed description of some examples presented below for the purpose of illustration. The quantities of parts or percentages of the constituents given below are to be understood as parts by weight or percentages by weight, unless stated otherwise. The abbreviation MB used in the examples refers to a basic mixture or master batch of the specified constituents; MFI stands for the melt flow index, which is measured according to ASTM D1238 at 190 ° C and under a load of 2.16 kg and is expressed in g / 10 min, unless otherwise stated.

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Examples

Example 1 (comparative example):

Small round seal with a diameter of 7 mm. An air blowing ring after the foam exits the nozzle allows the edge of the foam to solidify, which preserves the shape of the foam by preventing it from collapsing.

Components Parts Chlorine polyethylene (35% chlorine) 35 Low density polyethylene (LDPE, 926 kg / m ³ , melting temperature = 113 ° C, MFI [190 ° C - 2.16 kg] = 1.7 g / 10 min) 35 EVA (14% VA, melting temperature = 91 ° C, MFI [190 ° C - 2.16 kg] = 7 g / 10 min) 30th MB LDPE + Sb ₂ O ₃ (80:20) 5 MB 30% EVA + 70% glycerol monostearate 2.2 MB 60% carbon black + 40% LDPE 1 Oxidized polyethylene wax 1

The Sb ₂ O ₃ makes it possible to achieve a fire class for the foam. However, the combined nucleation effect of the Sb ₂ O ₃ and the CPE requires the addition of oxidized polyethylene wax, which makes it possible to control the cell size (EP1527132B1). The foam has fine lines (± 1000 / cm ² ); the

Quality is difficult to stabilize because the composition is very sensitive to temperature fluctuations. The temperature of the mass entering the extrusion die is 115.5 ° C, the pressure on the die is 39 bar. The density of the foam is 30 kg / m ³ .

The temperature regulation range to maintain open cell consistency and acceptable dimensions is only a few tenths of a degree (° C),

B E2016 / 5739 da. H. close to the control options in regulating the temperature of the zones of the process.

Example 2 (According to the Invention)

Extrusion on the same machine, with the same nozzle, with the same throughput and the same temperature of the zones of the cylinder as in Example 1.

Components Component category Parts SBS (KRATON D 1101) b 28 Low density polyethylene (LDPE, 926 kg / m ³ , melting temperature = 113 ° C, MFI [190 ° C - 2.16 kg] = 1.7 g / 10 min) a 42 EVA (18% VA, melting temperature = 86 ° C, MFI [190 ° C-2.16 kg] = 2 g / 10 min) c 30th ionomer SURLYN 1705-1 (zinc counterion, MFI [190 ° C-2.16 kg] = 5.5 g / 10 min) d 5 Glycerol monostearate 3rd MB 60% carbon black + 40% LDPE 0.4 MB LDPE + talc (75:25) 2nd

The foam does not contain Sb2C> 3. The ease of maintaining the quality of the open cells is better than that of Example 1. The temperature range in which a conformal foam is obtained is very wide, because between 114.4 ° C and 112.6 ° C (entering the extrusion die) Dimensions). The pressure on the tool is 60 bar, the density is 29.5 kg / m ³ , the cell size is ± 350 / cm ² . The supply pressure undeniably enables a considerable reduction in density.

Example 3 (comparative example):

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Extrusion on a different machine than in Examples 1 and 2.

Round seal with a diameter of ± 17 mm. An air-blowing ring after the foam emerges from the nozzle makes this possible

Allow the edge of the foam to solidify, which maintains the shape of the foam by preventing it from collapsing.

Components Parts SBS (KRATON D 1101) 24th Low density polyethylene (LDPE, 926 kg / m ³ , melting temperature = 113 ° C, MFI [190 ° C - 2.16 kg] = 1.7 g / 10 min) 36 EVA (18% VA, melting temperature = 86 ° C, MFI [190 ° C - 2.16 kg] = 2 g / 10 min) 30th MB LDPE + aluminum particles (60:40) 2.4 MB 10% EVA / 90% mixture of stearamide and palmitamide (65:35) 6 Metallocene polyethylene (QUEO 1001, density: 910 kg / m ³ , melting temperature = 106 ° C - MFI [190 ° C - 2.16 kg] = 1.0 g / 10 min) 10th MB LDPE + talc (50:50) 1

The metallocene polyethylene enables the stretch resistance of the foam to be improved. At a temperature of the entering the nozzle

Mass of 100.8 ° C, the cell structure is partially open, the density is 24 kg / m ³ , the pressure at the nozzle is 16 bar. When the temperature of the mass entering the extrusion die is increased by 1 ° C, the amount of open cells increases, but the surface of the foam looks less good and the foam collapses a little. It is not possible to find a satisfactory compromise.

Example 4 (According to the Invention)

Extrusion on the same machine as in example 3.

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Components Component category Parts SBS (KRATON D 1101) b 24th Low density polyethylene (LDPE, 926 kg / m ³ , melting temperature = 113 ° C, MFI [190 ° C -2.16 kg] = 1.7 g / 10 min) a 36 EVA (18% VA, melting temperature = 86 ° C, MFI [190 ° C-2.16 kg] = 2 g / 10 min) c 25th MB LDPE + aluminum particles (60:40) 2.4 ionomer SURLYN 1705-1 (zinc counterion, MFI [190 ° C-2.16 kg] = 5.5 g / 10 min) d 5 MB 10% EVA / 90% blend of stearamide and Palmitamide (65:35) 6 Metallocene polyethylene (QUEO 1001, density: 910 kg / m ³ , melting temperature = 106 ° C - MFI [190 ° C 2.16 kg] = 1.0 g / 10 min) 10th MB LDPE + talc (50:50) 1

With the same flow and gas controls as in Comparative Example 3, when the temperature of the mass entering the nozzle

103 ° C, the cell structure is closed. The density drops to 21.4 kg / m ³ , the pressure at the nozzle is 16.9 bar. In order to open the cells, the temperature of the mass entering the extrusion die is increased: to

103.6 ° C; the amount of open cells increases rapidly and becomes completely comparable to that of Example 1, but has much finer cells. The

The surface of the foam remains good and the foam does not collapse. The density is 20.7 kg / m ³ , the pressure 16.5 bar. The cell size comes close to that of Example 3. The stability of the quality of the foams (degree of open cells) is very good over time. When the foam is squeezed and the load is relaxed, the foam returns to its original dimension very quickly.

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Example 4b (According to the Invention)

Extrusion on the same machine as for example 4.

Components Component category Parts SBS (KRATON G 1652) b 24th Low density polyethylene (LDPE, 926 kg / m ³ , melting temperature = 113 ° C, MFI [190 ° C - 2.16 kg] = 1.7 g / 10 min) a 36 EVA (18% VA, melting temperature = 86 ° C, MFI [190 ° C-2.16 kg] = 2 g / 10 min) c 25th MB LDPE + aluminum particles (60:40) 2.4 ionomer SURLYN 1705-1 (zinc counterion, MFI [190 ° C - 2.16 kg] = 5.5 g / 10 min) d 5 MB 10% EVA / 90% blend of stearamide and Palmitamide (65:35) 6 Metallocene polyethylene (QUEO 1001, density: 910 kg / m ³ , melting temperature = 106 ° C - MFI [190 ° C 2.16 kg] = 1.0 g / 10 min) 10th MB LDPE + talc (50:50) 1

The foam is extruded at a temperature of the mass entering the extrusion die of 106.0 ° C (SEBS has a somewhat higher temperature resistance than SBS). The pressure at the nozzle is 20.8 bar, the foam is very good and the amount of open cells is also good as in example 4 according to the invention. The density is 23.6 kg / m ³ .

Example 5

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Extrusion on the same machine as for Examples 3 and 4. The MB 10%

EVA / 90% mixture of stearamide and palmitamide (65:35) is replaced by glycerol monostearate:

Components Component category Parts SBS (KRATON D 1101) b 24th Low density polyethylene (LDPE, 926 kg / m ³ , melting temperature = 113 ° C, MFI [190 ° C-2.16 kg] = 1.7 g / 10 min) a 36 EVA (18% VA, melting temperature = 86 ° C, MFI [190 ° C-2.16 kg] = 2 g / 10 min) c 25th MB LDPE + aluminum particles (60:40) 2.4 ionomer SURLYN 1705-1 (zinc counterion, MFI [190 ° C - 2.16 kg] = 5.5 g / 10 min) d 5 Glycerol monostearate 3rd Metallocene polyethylene (QUEO 1001, density: 910 kg / m ³ , melting temperature = 106 ° C - MFI [190 ° C 2.16 kg] = 1.0 g / 10 min) 10th MB LDPE + talc (50:50) 1

With the same gas flow and temperature controls as in Example 4, with the temperature of the mass entering the nozzle exceeding 103.9 ° C, the cell structure closes somewhat. The density is 21.6 kg / m ³ , the pressure at the nozzle is 17.7 bar. This is the effect of the less pronounced internal lubrication of the glycerol monostearate compared to the mixture of fatty acid amides. In order to open the cells, however, the temperature of the mass entering the extrusion die is increased to 104.4 ° C .; the amount of open cells increases rapidly and becomes completely comparable to that of Example 4, and the density increases to 26.7 kg / m ³ .

The surface of the foam remains good and the foam does not collapse. The temperature of the mass entering the extrusion die

BE2016 / 5739 is reduced a little to 104.0 ° C, the density drops to 25 kg / m ³ and the quality of the open cells is comparable to that of Example 4. Despite the less good lubrication of this composition, it is possible to obtain an open-line foam with a flexibility that matches that of the

State of the art f) is at least comparable, at the same time benefiting from an expanded regulation range for the temperature of the mass of the composition entering the nozzle.

Example 6 (comparative example):

Extrusion of a rectangular profile of 50 x 25 mm. An air blowing ring after the foam exits the nozzle allows the edge of the foam to solidify, which preserves the shape of the foam by preventing it from collapsing.

Components Parts Chlorine polyethylene (35% chlorine) 35 Low density polyethylene (LDPE, melting temperature = 113 ° C, 926 kg / m ³ , MFI [190 ° C - 2.16 kg] = 1.7 g / 10 min) 35 EVA (14% VA, melting temperature = 91 ° C, MFI [190 ° C - 2.16 kg] = 7 g / 10 min) 30th MB LDPE + talc (50:50) 0.1 MB 30% EVA + 70% glycerol monostearate 2.2 MB 60% carbon black + 40% LDPE 0.2

The foam is extruded at a temperature of the mass entering the extrusion die of 111.5 ° C., the pressure on the die is 22 bar. The density of the foam is 27.1 kg / m ³ , but the pressure on the mold is too low to be able to increase the gas content in order to lower the density due to a risk of pre-expansion (there would then not be enough pressure to keep the foaming gas in solution before the foams escape into the atmosphere). The foam is in terms of

BE2016 / 5739

The amount of open cells is very difficult to regulate (compressibility of the foam) because the temperature has a great influence on this composition (a few tenths of a degree are sufficient to change the content of open / closed cells).

A measurement of the temperature resistance, which consists in assessing the shrinkage of the foam after 16 hours of exposure to different temperatures, was carried out on this foam. The results are as follows:

Temperature (° C) Length (mm) Mean of the Shrinkage (mm) Mean of the Shrinkage (%) 20 ° C 400.0 80 ° C 388.0 -12.0 -3.0 90 ° C 381.0 -19.0 -4.8

Example 7

The same extruder, the same die as in Example 6, but with the following 15 composition:

Components Component category Parts SBS (KRATON D 1101) b 24th Low density polyethylene (LDPE, 926 kg / m ³ , melting temperature = 113 ° C, MFI [190 ° C - 2.16 kg] = 1.7 g / 10 min) a 36 Metallocene polyethylene (QUEO 1001, density: 910 kg / m ³ , melting temperature = 106 ° C - MFI [190 ° C 2.16 kg] = 1.0 g / 10 min) 10th EVA (18% VA, melting temperature = 86 ° C, MFI [190 ° C - 2.16 kg] = 2 g / 10 min) c 25th

BE2016 / 5739

ionomer SURLYN 1705-1 (zinc counterion, MFI [190 ° C - 2.16 kg] = 5.5 g / 10 min) d 5 MB LDPE + talc (50:50) 1.5 MB 30% EVA + 70% glycerol monostearate 3rd MB 60% carbon black + 40% LDPE 0.2

The metallocene polyethylene is used to improve the tensile strength of the formulation. The EVA copolymer used has a lower crystallinity than in Comparative Example 6, which enables the softness of the

Increase wording.

The foam is extruded at a temperature of the mass entering the extrusion die of 110.7 ° C, the pressure on the die is 23 bar. The density of the foam is 22.1 kg / m ³ (there is more gas than in

Comparative example 6 and the pressure on the tool is nevertheless at least the same). The foam is very easy to regulate in terms of the amount of open cells (compressibility of the foam), the quality of the open cells is completely comparable to that of the foam of comparative example 6. Talc could be added; the nucleation of the cells is less than that of Comparative Example 6 (which contains chloropolyethylene, which causes strong nucleation due to the additives it contains).

A measurement of the temperature resistance which consists of the shrinkage of the foam after 16 hours of exposure to different

Assessing temperatures was done on this foam. The results are as follows:

Temperature (° C) Length (mm) Mean of the Shrinkage (mm) Mean of the Shrinkage (%) 20 ° C 400.0 80 ° C 389.3 -10.7 -2.7 90 ° C 382.3 -17.7 -4.4

It is found that the performance in terms of shrinkage at the

Temperature of this foam even a little better than that of

Comparative example 6 is, although in example 7 according to the invention an EVA5 resin with a lower melting temperature ET is used, so that the

Density of the foam of the present example is 20% lower.

Example 8

The same extruder, the same die as in Examples 1 and 2, but with the following composition:

BE2016 / 5739

Components Component category Parts SBS (KRATON D 1101) b 28 Low density polyethylene (LDPE, 926 kg / m ³ , melting temperature = 113 ° C, MFI [190 ° C - 2.16 kg] = 1.7 g / 10 min) a 42 Metallocene polyethylene ENGAGE 8440 [DOW, OctenmLLDPE, density: 897 kg / m ³ , melting temperature = 93 ° C-MFI (190 ° C-2.16 kg) = 1.6] c 25th ionomer SURLYN 1705-1 (zinc counter ion, MFI [190 ° C-2.16 kg] = 5.5 g / 10 min) d 5 MB LDPE + talc (50:50) 2.5 Glycerol monostearate 3rd MB 60% carbon black + 40% LDPE 0.4

The foam is extruded at a temperature of the mass entering the extrusion die 15 of 106.4 ° C., the pressure on the die is 35 bar.

The density of the foam is 23 kg / m ³ . The foam is very soft, the cells are well opened, very light in terms of the number of open cells

BE2016 / 5739 to regulate, the quality of the open cells is completely comparable to that of the foam of Examples 1 and 2.

5-72.9

BE2016 / 5739

P-NMC-046 / BE

Claims (15)

EXPECTATIONS 1. Foam based on polyolefins, which comprises a mixture of the following components: (a) at least a first ethylene polymer selected from ethylene homopolymers made by a high pressure process and polar ethylene copolymers made by a high pressure process; (b) at least one thermoplastic elastomer with styrene blocks or at least one thermoplastic elastomer containing an elastomer phase of the cross-linked silicone type; (c) at least one second ethylene polymer that differs from the one or more Distinguishes ethylene polymers of component (a) and which has a melting point which is at least 5 ° C. lower than the first ethylene polymer of component (a) which has the lowest melting point, the at least one second ethylene polymer consisting of polar ethylene Copolymers made by a high pressure process; Metallocene polyethylenes or combinations thereof is selected; wherein the at least one second ethylene polymer acts as a cell opening agent; and (d) at least one ionomer. 2. Foam according to claim 1, wherein the ionomer or ionomers are selected from the group of polymers comprising acid groups which are at least partially neutralized by monovalent or divalent counterions, preferably ethylene-methacrylic acid copolymers. 3. Foam according to claim 2, wherein the monovalent or divalent counterions of sodium, lithium, calcium, magnesium and / or zinc BE2016 / 5739 are selected, the degree of neutralization of the acid groups preferably being less than 80%. 4. Foam according to one of claims 1 to 3, wherein the polar ethylene copolymers, which were produced by a high pressure process, the component (a) from ethylene-ethyl acrylate copolymers, ethylene-vinyl acetate copolymers, ethylene-butyl acrylate copolymers, ethylene-methyl acrylate copolymers or one Combination of several of these compounds are selected. 5. Foam according to one of claims 1 to 4, wherein the polar ethylene copolymers, which were produced by a high pressure process, the component (c) from ethylene-ethyl acrylate copolymers, ethylene-vinyl acetate copolymers, ethylene-butyl acrylate copolymers, ethylene-methyl acrylate copolymers or one Combination of several of these compounds are selected. 6. Foam according to one of claims 1 to 5, wherein the at least one thermoplastic elastomer with styrene blocks of component (b) made of styrene-butadiene-styrene copolymers, styrene-ethylene-butylene-styrene copolymers, Polystyrene b Polystyrene baths Polystyrene-b-polyisoprene-b-polystyrene copolymers, poly (ethylene-propylene) -b-polystyrene copolymers, poly (ethylene-ethylene / -propylene) -b-polystyrene copolymers, functionalized variants which include polar groups along the central elastomer block, or a combination of several of these compounds is selected. 7. Foam according to one of claims 1 to 6, wherein components (a), (b) and (c) each make up 5 to 85% by weight of the total composition and the ionomer or components (d) 0.1 to Make up 85% by weight of the total composition, preferably 0.5 to 20% by weight and particularly preferably 1 to 10% by weight. BE2016 / 5739 8. Foam according to any one of claims 1 to 7, which further comprises 1 to 50% by weight of metallocene polyethylene which has a melting point which is not at least 5 ° C lower than that of component (a), which has the lowest melting point has, based on the total composition. 9. Foam according to one of claims 1 to 8, which is also ordinary Includes additives and auxiliaries selected from the group consisting of nucleating agents, de-nucleating agents, dimensional stability control agents, antistatic agents, pigments, antioxidants, UV protection agents, lubricants, flame retardants and infrared reflecting / absorbing pigments and crystallization agents. 10. seal, liquid absorption foams, filters or sound absorption elements comprising a foam according to any one of claims 1 to 9. 11. A method of making a foam according to any one of claims 1 to 9, the method comprising the following steps: (i) dosing of components (a) - (d), premixed or individually dosed, for feeding an extruder; (ii) plasticizing and mixing the ingredients at a high temperature to melt and homogenize the ingredients; (iii) injecting a foaming gas; (iv) homogenizing the components and the gas; (v) cooling the mass; (vi) extruding through a temperature controlled die with a section of a predetermined shape in the open air causing foam formation; (vii) cooling the foam so formed. B E2016 / 5739 12. The method of claim 11, wherein the cooling of the foam in step (vii) is performed actively after exiting the nozzle. 5 13. The method of claim 11 or 12, wherein step (vii) further comprises Pulling and guiding the foam formed includes. 14. Use of a foam according to one of claims 1 to 9 or one obtained by the method according to one of claims 11 to 13 10 foams for the production of seals, Liquid absorption foams, filters or Sound absorption elements. BE2016 / 5739 OPEN-CELLED FOAMS MADE OF POLYOLEFINES Summary The invention relates to foams based on polyolefins which select a mixture of (a) at least one first ethylene polymer, which consist of ethylene homopolymers which have been produced by a high pressure process, and polar ethylene copolymers which have been produced by a high pressure process is; (b) with at least one thermoplastic elastomer 10 styrene blocks or at least one thermoplastic elastomer containing a cross-linked silicone type elastomer phase; (c) at least one second ethylene polymer which differs from the ethylene polymer (s) of component (a) and which has a melting point which is at least 5 ° C. lower than the first ethylene polymer of component (a) 15, which has the lowest melting point, the at least one second ethylene polymer from polar ethylene copolymers made by a high pressure process; Metallocene polyethylenes or combinations thereof is selected; wherein the at least one second ethylene polymer acts as a cell opening agent; and (d) at least one ionomer 20 include. tateniamft ftn «nt Office öftR« »wföp« 'e: i ^r ») $ Ri. certification «