DE102004009365A1 - Fuel tank for fluid, e.g. motor vehicles petrol, comprises exposed barrier layer of ethylene vinyl alcohol based material - Google Patents

Abstract

A fuel tank (10) comprises first layer of high-density polyethylene; a layer of binder; and an exposed barrier layer of ethylene vinyl alcohol based material.

Description

The invention relates to a fuel tank for a Automobile and in particular a multi-layer fuel tank Plastic.

• – Polyethylen hoher Dichte (High density polyethylene, HDPE);
• – einem Bindemittel;
• – einem Polyamid (PA) oder einem Copolymer, der Ethyleneinheiten und Vinylalkoholeinheiten (EVOH) enthält;
• – einem Bindemittel;
• – HDPE.

European patent EP742 236 describes gasoline tanks consisting of the following five layers:

• - High density polyethylene (HDPE);
• A binder;
• A polyamide (PA) or a copolymer containing ethylene units and vinyl alcohol units (EVOH);
• A binder;
• - HDPE.

A sixth location can be between one the binder layers and one of the HDPE layers are inserted. This sixth layer consists of manufacturing scrap, which forms during molding the tanks are formed, and to a much lesser extent not compliant tanks. This committee and the non-compliant Tanks are then ground until granules are obtained. This ground material is then melted again and directly in the tank coextrusion line extruded. The milled material can also be melted and redone by means of an extruding machine, e.g. a twin-screw brother be granulated before it is used again.

According to a variant, the recycled Product mixed with the HDPE from the two outer layers of the tank become. For example, Is it possible, that the granules of the recycled product with granules of fresh HDPE of these two layers is mixed. It is also possible to have one to use any combination of these two recyclings. Of the Content of recycled material can be up to 50% of the total weight represent the tank.

The European patent EP 731 308 describes a tube having an inner layer containing a mixture of polyamide and polyolefin with a polyamide matrix, and an outer layer containing a polyamide. These polyamide-based tubes are used for transporting gasoline and, in particular, for transporting the gasoline from the motor vehicle tank to the engine, with larger diameter but also for transporting hydrocarbons to service stations between the distributor pumps and the underground storage tanks.

According to another form of a Pipe may be a layer of a polymer, ethylene units and vinyl alcohol units Contains (EVOH), between the inner and outer layers added become. The structure: inner layer / EVOH / binder / outer layer is used advantageously.

In the EP 742 236 described tanks, in which the Spenlage is not in direct contact with the gasoline, admittedly have Speneigenschaften, but they are not enough, if very low gasoline losses are desired. EP 731 308 describes tubes whose outer layer is made of polyamide and in which the Spenlage is in direct contact with the gasoline, wherein the polyamide layer for the mechanical strength of the construction is necessary. New structures have been found which have better sputtering properties and are useful for various applications, such as automotive fuel tanks.

The present invention relates a plastic fuel tank with a multi-layered wall structure, at which a Spenlage forms an exposed side of the wall and preferably in direct contact with the fuel contained therein stands. The sponge layer of the structures of the invention forms one of exposed sides of the structure, i. it is not an inner one Location of the wall structure. Fuel tank structures embodying the invention embody, have walls, for example made of HDPE / Spenlage or HDPE / binder / barrier layer, where "HDPE" for polyethylene high density stands.

• – eine erste Lage aus Polyethylen hoher Dichte (HDPE),
• – eine Bindemittellage,
• – eine zweite Lage aus EVOH oder einer Mischung auf der Basis von EVOH, und
• – optional eine dritte Lage aus Polyamid (A) oder einer Mischung aus Polyamid (A) und Polyolefin (B).

Preferably, the fuel tank structure comprises in turn:

• A first layer of high density polyethylene (HDPE),
• A binder layer,
• A second layer of EVOH or a mixture based on EVOH, and
• Optionally a third layer of polyamide (A) or a mixture of polyamide (A) and polyolefin (B).

The following is the second location or the combination of the second and third layers is referred to as the "blocking position" and forms an outer surface of the Wall structure.

The invention is particularly suitable for one liquid such as automotive fuel or volatile hydrocarbon fuels such as. Gasoline, as losses are avoided by the structure so as not to pollute the environment.

The fuel tank according to the invention has the advantages that significantly less hydrocarbon fuel is emitted, that it meets strict environmental standards and requirements, economical to produce and assemble is and a long Life has.

The invention will now be described with reference to embodiments with reference to the accompanying drawings. In the drawings demonstrate:

1 a perspective view of an automotive plastic fuel tank according to a presently preferred embodiment of the invention;

2 a section of a section through a wall of the fuel tank of the 1 ; and

3 a section of a section through a wall of a gas tank according to another embodiment of the invention;

4 a section of a section through a wall of a fuel tank according to yet another presently preferred embodiment of the invention; and

5 an enlarged section of a section through a portion of the wall of the fuel tank as in 4 in the area of a squeeze line of the fuel tank.

1 illustrates an automotive fuel tank 10 plastic according to an embodiment of this invention with a wall 12 with a filler neck or pipe 14 made of plastic with a flange 16 and a fuel pump module 18 with a cover flange 20 each heat-welded to the wall. As in 2 shown, points the wall 12 an exposed first outer layer 22 made of HDPE, an inner exposed second layer 24 EVOH and a binder layer 26 in between, which glues the first and second layers together. The second location 24 is in contact with liquid fuel in the tank 10 and provides the primary vapor barrier, and the first layer 22 Ensures the primary strength and structural integrity of the tank. The adhesive layer joins the dissimilar first and second layers or allows them to adhere to each other.

3 illustrates a modified wall construction 12 ' a fuel tank 10 with an inner first layer 22 made of HDPE, an outer exposed second layer 24 EVOH and a binder layer 26 in between, which glues the first and second layers together. In both embodiments of the tank, the second vapor barrier layer 26 preferably also a third film or a third layer from EVOH 28 of a polyamide (A) or a mixture of a polyamide (A) and a polyolefin (B).

Preferably, the fuel tank 10 formed by simultaneously co-extruding all the layers and adhesives into a hollow preform, which is then placed in a mold having a cavity of the desired shape and configuration of the tank. The preform is then blow-molded to form the fuel tank.

The first location 22 is made of high density polyethylene (HDPE), which may also be blended with some carbon black or polish black for the purpose of coloration, and may also contain a regrind layer of HDPE made of regrinded broke from the manufacture of the fuel tanks 10 and / or recovered and re-milled HDPE. The first location 22 and an optionally present remelted layer preferably have substantially the same composition. The adhesive layer can be made of a wide variety of materials and is necessary to secure the layer of HDPE to the second vapor barrier layer and thus the structural integrity of the fuel tank 10 essential to meet various crash safety specifications of the automotive industry. The second vapor barrier layer is necessary to reduce the amount of hydrocarbon vapor passing through the wall 12 diffuse or escape from the fuel tank, which consists primarily of HDPE.

A typical multi-layer fuel tank wall 10 made of plastic has a thickness between about 3 mm and 10 mm, with an optimum total wall thickness of about 5 to 6 mm. Nominal values for the individual layers of the multi-layer plastic fuel tank 10 are as follows: the first location 22 accounts for between about 90 and 97% of the total wall thickness; the binder or adhesive layer 26 makes up between about 1 and 4% of the total wall thickness; and the second vapor barrier layer 24 or the second and third layers 24 . 28 together account for between about 2 and 6% of the total wall thickness. These areas of thickness of the individual layers are given by way of illustration only and may be used in the co-extrusion of the fuel tank wall preform 12 during the manufacture of the fuel tank 10 of course be varied.

During a manufacturing period of the fuel tanks 10 the thickness of the individual layers must be controlled to ensure optimum performance and quality of the fuel tank 10 in use. The thickness of the first layer 22 made of polyethylene is important as this layer is the vapor barrier layer (s) 24 . 28 Structurally protects and also strength and structural integrity of the fuel tank 10 self supplies. The thickness of the adhesive layer 26 is important to ensure sufficient adhesion between the adjacent layers of HDPE and the vapor barrier layer (s) 24 . 28 to secure. Finally, the thickness of the vapor barrier layer (s) 24, 28 is important to the Permeation (penetration) of hydrocarbon vapors through the fuel tank 10 and to prevent the atmosphere.

As for the first layer, high density polyethylene (HDPE) is described in Kirk-Othmer, 4th Edition, Vol. 17, pp. 704 and 724 to 725. According to ASTM D 1248-84, this is an ethylene polymer having a density of at least 0.940. The name HDPE denotes both ethylene homopolymers and copolymers thereof with small amounts of olefin. The density is advantageously between 0.940 and 0.965. In the present invention, the MFI of the HDPE is advantageously between 0.1 and 50. As an example, Eltex B 2008 ^® with a density of 0.958 and an MFI of 0.9 (in g / 10 min at 190 ° C under 2.16 kg), Finathene ^® MS201B of FINA and Lupolen ^® 4261 mentioned AQ from BASF.

As for the second situation, it will the EVOH copolymer also as saponified ethylene-vinyl acetate copolymer designated. The according to the present Invention saponified ethylene-vinyl acetate copolymer to be used is a copolymer with an ethylene content of between 20 and 70 Mol%, preferably between 25 and 70 mol%, wherein the degree of saponification the vinyl acetate component is not less than 95 mol%. At an ethylene content less than 20 mol% are the barrier properties under conditions high humidity not as high as you might want, while an ethylene content greater than 70 mol% leads to reductions in barrier properties. If the degree of saponification or the degree of hydrolysis is less than 98 mol% is, the barrier properties are sacrificed.

The term "barrier properties" refers to the impermeability for gases, liquids and in particular oxygen, and in motor vehicles for fuel. More particularly, the invention relates to fuels or volatile hydrocarbon fuels like gasoline for Motor vehicles.

Among these saponified copolymers are those who are under Conditions have melt indices ranging from 0.5 to 100 g / 10 min, especially useful. Advantageously, the MFI is between 5 and 30 (g / 10 min at 230 ° C under 2.16 kg), where MFI is the abbreviation for "melt flow Index "(melt index), the flow rate in the molten state.

It goes without saying that This saponified copolymer contains small amounts of other comonomer ingredients may contain, including α-olefins such as. Propylene, isobutene, α-octene, α-dodecene, α-octadecene, etc., unsaturated carboxylic acids or their salts, partial alkyl esters, full alkyl esters, nitriles, amides and anhydrides of said acids and unsaturated sulfonic acids or their salts.

What the EVOH based blends are concerned, these are designed so that the EVOH forms the matrix, i.e. it represents at least 40% by weight of the mixture, and preferably at least 50%. The other components of the mixture are selected from Polyolefins, polyamides and "optional" functional polymers.

• – 55 bis 99,5 Teile von EVOH-Copolymer,
• – 0,5 bis 45 Teile Polypropylen und Kompatibilisierer, wobei die Anteile davon so verteilt sind, dass das Verhältnis der Menge von Polypropylen zur Menge von Kompatibilisierer zwischen 1 und 5 liegt.

As a first example of these second layer mixtures based on EVOH, compositions are mentioned which contain (by weight):

• 55 to 99.5 parts of EVOH copolymer,
• From 0.5 to 45 parts of polypropylene and compatibilizer, the proportions of which are distributed so that the ratio of the amount of polypropylene to the amount of compatibilizer is between 1 and 5.

Advantageous is the ratio of MFI of EVOH to MFI of polypropylene greater than 5 and preferably between 5 and 25. Advantageously, the MFI of the polypropylene is between 0.5 and 3 (in g / 10 min at 230 ° C and 2.16 kg). According to one advantageous embodiment the compatibilizer is a polyethylene with polyamide plug (on English: "polyethylene bearing polyamide grafts ") and arises from the reaction of (i) a copolymer of ethylene and a grafted or copolymerized unsaturated monomer X with (ii) a polyamide. The copolymer of ethylene and a grafted or copolymerized unsaturated monomer X is chosen X is copolymerized and may be selected from ethylene-maleic anhydride copolymers and ethylene-alkyl (methyl) acrylate-maleic anhydride copolymers, these copolymers being between 0.2 and 10% by weight maleic anhydride and between 0 and 40% by weight of alkyl (methyl) acrylate. According to one further advantageous embodiment the compatibilizer is a polypropylene with polyamide plug ( "Polypropylene bearing polyamide grafts ") which consists of the reaction of (i) a propylene homopolymer or copolymer with a grafted or copolymerized unsaturated monomer X with (ü) a polyamide is formed. Advantageously, X is grafted. The monomer X is advantageously an unsaturated carboxylic acid anhydride such as e.g. Maleic anhydride.

• – 50 bis 98 Gew.% eines EVOH-Copolymers,
• – 1 bis 50 Gew.% eines Polyethylens,
• – 1 bis 15 Gew.% eines Kompatibilisierers, der aus einer Mischung eines LLDPE Polyethylens oder Metallocens und einem Polymer besteht, der ausgewählt ist aus Elastomeren, Polyethylenen mit sehr geringer Dichte und Metallocenpolyethylenen, wobei die Mischung mit einer unsaturierten Carboxylsäure oder einem funktionellen Derivat dieser Säure co-gepfropft („cografted") ist.

As a second example of these EVOH-based mixtures, the following compositions are mentioned, which contain:

• From 50 to 98% by weight of an EVOH copolymer,
• From 1 to 50% by weight of a polyethylene,
• From 1 to 15% by weight of a compatibilizer consisting of a blend of an LLDPE polyethylene or metallocene and a polymer selected from elastomers, very low density polyethylenes and metallocene polyethylenes, said admixture with an unsatured carboxylic acid or a functional derivative thereof Acid is co-grafted.

Advantageously, the compatibilizer is chosen such that the MFI ₁₀ / MFI ₂ ratio is between 5 and 20, MFI _{2 being} the mass melt index at 190 ° C under a 2.16 kg load as measured in accordance with ASTM D 1238 and MFI ₁₀ of Mass melt index at 190 ° C under a load of 10 kg according to ASTM D 1238.

As a third example of this up EVOH based blends of the second layer become the following Called compositions, which contain:

- 50 to 98% by weight of an EVOH copolymer,

- 1 to 50% by weight of an ethylene alkyl (meth) acrylate copolymer,

- 1 to 15% by weight of a compatibilizer resulting from the reaction (i) a copolymer of ethylene and a grafted or copolymerized one unsatured monomer X has been formed with (ii) a copolyamide.

It is advantageous in the case of the copolymer made of ethylene and a grafted or copolymerized unsaturated Monomer X, that X is copolymerized and a copolymer of ethylene from maleic anhydride or a copolymer of ethylene, from alkyl (meth) acrylate and maleic anhydride. Advantageously, these copolymers include between 0.2 and 10% by weight of maleic anhydride and between 0 and 40% by weight of alkyl (meth) acrylate.

What the polyamide (A) and the mixture of polyamide (A) and polyolefin (B) of the third layer the term "polyamide" the following condensation products:

- one or more amino acids, such as. aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid of one or more lactams, e.g. Caprolactam, Oenantholactam and lauryl lactam;

- on or more salts or mixtures of diamines, e.g. hexamethylene diamine, Dodecamethylenediamine, meta-xylylenediamine, bis (paminocyclohexyl) methane and trimethylhexamethylenediamines with dibasic acids such as e.g. isophthalic acid, terephthalic acid, adipic acid, azelaic acid, suberic ( "Suberic acid "), sebacic acid and Dodecandicarboxylsäure.

As examples of polyamides, PA 6 and PA 6-6. It is also advantageously possible copolyamides to use. Mentioned can be also the copolyamides resulting from the condensation of at least two α, ω-aminocarboxylic or of two lactams or of a lactam and an α, ω-aminocarboxylic acid result. For this one can also mention the Copolyamide, resulting from the condensation of at least one α, ω-aminocarboxylic acid (or a lactam), at least one diamine and at least one dicarboxylic acid.

As examples of lactams, mention may be made of such lactams, containing between 3 and 12 carbon atoms on the main ring and which may be substituted. Mentioned can be e.g. β, β-dimethylpriolactam, α, α-dimethylpriolactam, Amylolactam, caprolactam, caupyllactam and lauryl lactam.

As examples of α, ω-aminocarboxylic acids, aminoundecanoic acid and aminododecanoic acid may be mentioned. As examples of dicarboxylic acids, adipic acid, sebacic acid, isophthalic acid, butanedioic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, sodium or lithium salts of sulfoisophthalic acid, dimerized fatty acids (these dimerized fatty acids have a dimer content of at least 98% and are preferably hydrogenated) and dodecanedioic acid HOOC - (CH ₂ ) ₁₀ -COOH.

The diamine can be an aliphatic Diamine with 6 to 12 atoms, it can be acrylic and / or saturated be cyclical. As examples can Hexamethylenediamine, piperazine, tetramethylenediamine, octamethylenediamine, Decamethylenediamine, dodecamethylenediamine, 1,5-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane, diamine polyols, Isophorone diamine (IPD), methylpentametylenediamine (MPDM), bis (aminocyclohexyl) methane (BACM) and bis (3-methyl-4-aminocyclohexyl) methane (BMACM).

Examples of copolyamides can be copolymers from caprolactam and lauryl lactam (PA6 / 12), copolymers of caprolactam, from adipic acid and hexamethylenediamine (PA 6 / 6-6), copolymers of caprolactam, from lauryl lactam, from adipic acid and hexamethylenediamine (PA 6/12 / 6-6), copolymers of caprolactam, from lauryl lactam, from 11-aminoundecanoic acid, from azanoic acid and from hexamethyldiamine (PA 6 / 6-9 / 11/12), copolymers of caprolactam, from lauryl lactam, from 11-aminoundecanoic acid, from adipic acid and hexamethylenediamine (PA 6 / 6-6 / 11/12) and copolymers of laurolactam, from azelaic acid and from hexamethylenediamine (PA 6-9 / 12).

Advantageously, the copolyamide is selected from PA 6/12 and PA 6 / 6-6. The advantage of these copolyamides is that their melting point is lower is the one of PA 6.

It is also possible to have any amorphous To use polyamide, which has no melting point.

The MFI of polyamides and blends of polyamides and of polyolefin of the present invention according to the im State of the art known rules at a temperature of 15 to 20 ° C above the Melting point of the polyamide measured. Regarding to PA 6 based blends, the MFI is measured at 235 ° C under 2.16 kg. Regarding of the PA 6-6 based blends, the MFI becomes less than 1 at 275 ° C kg measured.

Polyamide blends can be used become. Advantageously, the MFI of the polyamides is between 1 and 50 g / 10 min.

One would not abandon the context of the invention if some of the polyamide (A) were replaced by a Co polymer containing polyamide blocks and polyether blocks, that is, when using a mixture containing at least one of the above polyamides and at least one copolymer containing polyamide blocks and polyether blocks.

• 1) Polyamidsequenzen enthaltend Diaminkettenenden mit Polyoxyalkylensequenzen enthaltend Dicarboxylkettenenden.
• 2) Polyamidsequenzen enthaltend Dicarboxylkettenenden mit Polyoxyalkylensequenzen enthaltend Diaminkettenenden, welche durch Cyanoehty lierung und Hydrierung von α,ω-dihydroxylierten aliphatischen Polyoxyalkylensequenzen, auch als Polyetherdiole bekannt, erhalten werden.
• 3) Polyamidsequenzen enthaltend Dicarboxylkettenenden mit Polyetherdiolen, wobei die in diesem besonderen Fall erhaltenen Produkte Polyetheresteramide sind. Diese Copolymere werden vorteilhaft verwendet.

The copolymers containing polyamide blocks and polyether blocks result from the copolycondensation of reactive end-terminated polyamide sequences with polyether sequences containing reactive ends, such as, inter alia:

• 1) polyamide sequences containing diamine chain ends with polyoxyalkylene sequences containing dicarboxylic chain ends.
• 2) polyamide sequences containing dicarboxylic chain ends with polyoxyalkylene sequences containing diamine chain ends which are obtained by cyanoethylation and hydrogenation of α, ω-dihydroxylated aliphatic polyoxyalkylene sequences, also known as polyether diols.
• 3) polyamide sequences containing dicarboxylic chain ends with polyether diols, the products obtained in this particular case being polyetheresteramides. These copolymers are used advantageously.

The polyamide sequences, the dicarboxylic chain ends contain, e.g. from the condensation of α, ω-aminocarboxylic acids, lactams or dicarboxylic acids and diamines in the presence of a chain limiting dicarboxylic acid.

The polyether may e.g. a polyethylene glycol (PEG), a polypropylene glycol (PPG) or a polytetramethylene glycol Be (PTMG). The latter is also known as polytetrahydrofuran (PTHF).

The number average molar mass M _{n of} the polyamide sequences is between 300 and 15,000 and preferably between 600 and 5,000. The mass M _{n of} the polyether sequences is between 100 and 6,000 and preferably between 200 and 3,000.

The polymers containing polyamide blocks and polyether can contain also by chance comprise distributed units. These polymers can by the simultaneous reaction of the polyether and a polyamide block precursor.

For example, is it possible polyetherdiod, a lactam (or an α, ω-amino acid) and a chain limiting dibasic acid in the presence of a small Amount of water to react with each other. You get one Polymer, consisting essentially of polyether blocks, polyamide blocks of very different length but also contains different reagents that have reacted randomly and along the polymer chain random are distributed.

Whether this from the copolycondensation derived from polyamide and previously prepared polyether sequences or from a one-step reaction, these polymers, the polyamide blocks and polyether contain, e.g. D-shore hardness, which are between 20 and 75 and advantageously between 30 and 70 can and an inherent viscosity between 0.8 and 2.5, measured in meta-cresol at 250 ° C for an initial concentration of 0.8g / 100ml. The FMI values can between 5 and 20 (235 ° C under a load of 1 kg).

The polyetherdiol blocks are either as they are or with polyamide blocks, the carboxyl ends contained, copolycondensed, or they are aminated so that they are converted to polyether diamines and condensed with polyamide blocks which contain carboxyl ends. You can also use polyamide precursors and a chain limiter to produce polymers, the polyamide blocks and polyether blocks with random contain distributed units.

Polymers containing polyamides and polyether blocks, are disclosed in U.S. Patents 4,331,786; 4,115,475; 4 195 015; 4,839,441; 4,864,014; 4,230,838 and 4,332,920.

The ratio of the amount of copolymer, the polyamide blocks and polyether blocks contains to the amount of polyamide is advantageous based on the weight between 10/90 and 60/40. Mentioned can be e.g. Mixtures of (i) PA 6 and (ii) Copolymer with PA 6 blocks and PTMG blocks and mixtures of (i) PA 6 and (ii) copolymer with PA 12 blocks and PTMG blocks.

What the polyolefin (B) of the mixture of polyamide (A) and polyolefin (B) of the third layer, this may functionalized or non-functionalized or a mixture of at least one functionalized and / or at least one be non-functionalized. For simplicity, functionalized Polyolefins (B1) and non-functionalized polyolefins (B2) below described.

A non-functionalized polyolefin (B2) is conventional a homopolymer or copolymer of α-olefins or of diolefins such as. Ethylene, propylene, 1-butene, 1-octene or butadiene. As Example can mentioned become:

• – Propylenhomopolymere oder Copolymere;
• – Ethylen/α-Olefin Copolymere wie z.B. Ethylen/Propylen, EPR (Abkürzung für ethylene-propylene-rubber) und Ethylen/Propylen/Dien (EPDM);
• – Styren/Ethylen-Buten/Styren (SEBS), Styren/Butadien/Styren (SBS), Styren/Isopren/Styren (SIS) oder Styren/Ethylen-Propylen/Styren (SEPS) Block Copolymere;
• – Copolymere von Ethylen mit wenigstens einem Produkt, welches ausgewählt ist aus unsaturierten Carboxylsäuresalzen oder -estern, wie z.B. Alkyl(meth)acrylat (z.B. Methylacrylat) oder saturierten Carboxylsäurevinylestern, wie z.B. Vinylacetat, wobei es möglich ist, dass der Anteil von Comonomer bis zu 40 Gew.% beträgt.

Polyethylene homopolymers and copolymers, in particular LDPE, HDPE, linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE) and very low density polyethylene) and metallocene polyethylene;

• - propylene homopolymers or copolymers;
• Ethylene / α-olefin copolymers such as ethylene / propylene, EPR (abbreviation for ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM);
• Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS) or styrene / ethylene-propylene / styrene (SEPS) block copolymers;
• Copolymers of ethylene with at least one product selected from unsaturated carboxylic acid salts or esters, such as alkyl (meth) acrylate (eg, methyl acrylate) or saturated carboxylic acid vinyl esters, such as vinyl acetate, it being possible for the proportion of comonomer to be up to 40% by weight.

The functionalized polyolefin (B1) may be an α-olefin polymer with reactive units (functionalities); such reactive Units are acid, Anhydride or epoxy functions. As an example, the above polyolefins (B2) mentioned obtained with unsaturated epoxides, e.g. Glycidyl (meth) acrylate or with carboxylic acids or the corresponding salts or esters, e.g. (Meth) acrylic acid (wherein the latter wholly or partly with metals such as e.g. Zn etc. may be neutralized or alternatively with anhydrides of carboxylic acids such as Maleic anhydride) are grafted or copolymerized or terpolymerized. On functionalized polyolefin is e.g. a PE / EPR blend, at which the weight ratio within a big one Range may vary, e.g. between 40/60 and 90/10, with the Co-grafted with an anhydride, especially with maleic anhydride, corresponding to a degree of grafting of e.g. between 0.01 and 5 wt.%.

• – PE, PP, Copolymere von Ethylen mit Propylen, Buten, Hexen oder Octen, die z.B. zwischen 35 und 80 Gew.% Ethylen enthalten;
• – Ethylen/α-Olefin Copolymere wie z.B. Ethylen/Propylen Copolymere, EPR (Abkürzung für ethylene-propylene-rubber) und Ethylen/Propylen/Dien (EPDM) Copolymere;
• – Styren/Ethylen-Buten/Styren (SEBS), Styren/Butadien/Styren (SBS), Styren/Isopren/Styren (SIS) oder Styren/Ethylen-Propylen/Styren (SEPS) Blockcopolymere;
• – Ethylen-Vinylacetat (EVA) Copolymere, die bis zu 40 Gew.% Vinylacetat enthalten;
• – Copolymere von Ethylen und einem Alkyl(meth)acrylat, welche bis zu 40 Gew.% Alkyl(meth)acrylat enthalten;
• – Ethylenvinylacetat (EVA) und Alkyl(meth)acrylat Copolymere, welche bis zu 40 Gew.% Comonomere enthalten.

The functionalized polyolefin (B1) may be selected from the following (co) polymers grafted with maleic anhydride or glycidyl methacrylate, wherein the degree of grafting is, for example, between 0.01 and 5% by weight.

• - PE, PP, copolymers of ethylene with propylene, butene, hexene or octene, for example, between 35 and 80 wt.% Ethylene;
• Ethylene / α-olefin copolymers such as ethylene / propylene copolymers, EPR (abbreviation for ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM) copolymers;
• Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS) or styrene / ethylene-propylene / styrene (SEPS) block copolymers;
• Ethylene-vinyl acetate (EVA) copolymers containing up to 40% by weight of vinyl acetate;
• Copolymers of ethylene and an alkyl (meth) acrylate containing up to 40% by weight of alkyl (meth) acrylate;
• Ethylene vinyl acetate (EVA) and alkyl (meth) acrylate copolymers containing up to 40% by weight of comonomers.

The functionalized polyolefin (B1) may also be selected from ethylene / propylene copolymers which are predominantly Propylene, which is grafted with maleic anhydride and then condensed with monoamine polyamide (or a polyamide oligomer) is (products described in EP-A-0 342 066).

• – Ethylen/Alkyl(meth)acrylat/(meth)acrylsäure oder Maleinanhydrid oder Glycidylmethacrylat Copolymere;
• – Ethylen/Vinylacetat/Maleinanhydrid oder Glycidylmethacrylat Copolymere;
• – Ethylen/Vinylacetat oder Alkyl(meth)acrylat/(meth)acrylsäure oder Maleinanhydrid oder Glycidylmethacrylat Copolymere.

The functionalized polyolefin (B1) may also be a co- or terpolymer having at least the following units: (1) ethylene, (2) alkyl (meth) acrylate or saturated carboxylic acid such as vinyl ester and (3) anhydride eg maleic anhydride or (meth) acrylic acid or epoxide such as glycidyl (meth) acrylate. As examples of functionalized polyolefins of the latter type, mention may be made of the following copolymers in which ethylene is preferably at least 60% by weight and in which the termonomer (function) represents, for example, from 0.1 to 10% by weight of the copolymer:

• Ethylene / alkyl (meth) acrylate / (meth) acrylic acid or maleic anhydride or glycidyl methacrylate copolymers;
• Ethylene / vinyl acetate / maleic anhydride or glycidyl methacrylate copolymers;
• Ethylene / vinyl acetate or alkyl (meth) acrylate / (meth) acrylic acid or maleic anhydride or glycidyl methacrylate copolymers.

In the previous copolymers may be the (meth) acrylic acid form a salt with Zn or Li.

The term "alkyl (meth) acrylate" in (B1) or (B2) denotes C1 to C8 alkyl methacrylates and acrylates and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

Further, the above-mentioned polyolefins (B1) also by a suitable method and means (Diepoxyd, dibasic acid, Peroxide, etc.) are crosslinked; the term "functionalized polyolefin" also includes mixtures the above mentioned Polyolefins with a difunctional reagent, e.g. divalent Acid, Dianhydride, diepoxy, etc., which can react with the latter, or Mixtures of at least two functionalized polyolefins, who can react with each other.

The above-mentioned copolymers, (B1) and (B2) can at random Way or blockwise copolymerized and can be a have linear or branched structure.

The molecular weight, the MFI index and the density of these polyolefins can also be in a wide range vary, which is clear to those skilled in the art. MFI, the abbreviation for melt flow Index (melt index) is the flow rate in the molten one State. He will be in accordance with the ASTM Standard 1238 measured.

Advantageous are the non-functionalized Polyolefins (B2) selected of polypropylene homopolymers or copolymers and any one of Homopolymer of ethylene or a copolymer of ethylene and a Comonomer of a higher α-olefinic Type such as e.g. Butene, hexene, octene or 4-methyl-1-pentene. Be mentioned can e.g. PPs, high density PEs, medium density PEs, linear Low density PEs, low density PEs and very high PEs low density. Of these polyethylenes, those skilled in the art will know that they produce according to a "radical-mediated" process be, according to a catalysis of the "Ziegler" type, or lately according to a so-called "metallocene" catalysis.

Advantageously, the functionalized polyolefins (B1) are selected from any polymer comprising α-olefin units and units which contain reactive polar functions, such as epoxide, carboxylic acid or carboxylic acid anhydride functions. As examples of such polymers, for example, the terpolymers of ethylene, are mentioned by Alcylacrylat and of maleic anhydride or of glycidyl methacrylate, such as the products Lotader ^® from Elf Atochem SA or Polyelefine, which are grafted with maleic anhydride, such as the products Orevac ^® from ELF Atochem SA, as well as terpolymers of ethylene, of alkyl acrylate and of (meth) acrylic acid. Polypropylene homopolymers or copolymers grafted with a carboxylic acid anhydride and then condensed with polyamides or monoamino polyamide oligomers may also be mentioned.

The MFI of (A) and the MFI of (B1) and (B2) can be selected within a wide range, but it is recommended that the MFI of (A) be greater than that of (B) to facilitate the dispersion of (B).

For small portions of (B), e.g. 10 to 15 parts, it is sufficient to use non-functionalized polyolefin (B2). The amount of (B2) and (B1) in the phase (B) depends on the amount of in (B1) existing functions, as well as their reactivity. Advantageous be (B1) / (B2) weight ratios ranging from 5/35 to 15/25. For small proportions of (B) is it also possible use only a mixture of polyolefins (B 1) to crosslink to obtain.

According to a first preferred embodiment of the invention the polyolefin (B) (i) a high density polyethylene (HDPE) and (ii) a mixture of a polyethylene (C1) and a polymer (C2) consisting of Elastomers, very low density polyethylenes and ethylene copolymers selected wherein the mixture (C1) + (C2) is grafted with an unsatured carboxylic acid is.

According to a second preferred embodiment of the invention the polyolefin (B) (i) polypropylene and (ii) a polyolefin which resulting from the reaction of a polyamide (C4) with a copolymer (C3), which is propylene and a grafted or copolymerized unsaturated Monomer X comprises.

According to a third preferred embodiment of the invention the polyolefin (B) (i) a polyethylene of the type LLDPE, VLDPE or Metallocene and (ii) an ethylene alkyl (meth) acrylate-maleic anhydride copolymer.

According to a fourth preferred embodiment of the invention is the polyamide (A) selected from mixtures of (i) Polyamide and (ii) a copolymer containing PA 6 blocks and PTMG blocks contains and Mixtures of (i) polyamide and (ii) a copolymer containing PA 12 blocks and PTMG blocks; the ratio the amounts of copolymer and polyamide by weight between 10/90 and 60/40 lies. According to one In the first variant, the polyolefin (B) (i) comprises a polyethylene of the Type LLDPE, VLDPE or metallocene and (ii) an ethylene-alkyl (meth) acrylate-maleic anhydride copolymer; according to a second variant, the polyolefin comprises two functionalized polymers, which comprise at least 50 mol% of ethylene units and react can, to form a crosslinked phase.

As regards the first embodiment, the proportions (by weight) are advantageously as follows:
60 to 70% polyamide,
5 to 15% of the co-grafted mixture of (C1) and (C2),
the remainder being high density polyethylene.

What the high density polyethylene is concerned, its density is advantageously between 0.940 and 0.965 and the MFI between 0.1 and 5 g / 10 minutes (190 ° C, 2.16 kg).

The polyethylene (C1) can from the mentioned above Polyethylenes selected his. Advantageously (C 1) is a high density polyethylene (HDPE) with a density of between 0.940 and 0.965. The MFI of (C1) is between 0.1 and 3g / 10 minutes (under 2.16 kg -190 ° C).

The copolymer (C2) may e.g. on Ethylene / propylene elastomer (EPR) or an ethylene / propylene / diene elastomer Be (EPDM). (C2) can also be a very low density polyethylene (VLDPE), which may be either an ethylene homopolymer or a copolymer of ethylene and an α-olefin is. (C2) may also be a copolymer of ethylene with at least one Be product that selected is made from (i) unsaturated carboxylic acids, their salts, their esters, (ii) vinyl esters and saturated carboxylic acids, (iii) unsaturated dicarboxylic acids, their salts, their esters, their hemiestern and their anhydrides. Advantageously, (C2) is an EPR.

Advantageously, 60 to 95 parts from (C1) to 40 to 5 parts of (C2).

The mixture of (C1) and (C2) is grafted with an unsaturated carboxylic acid, ie (C1) and (C2) are co-grafted. It would not be a departure from the context of the invention, a functional derivative of the acid. Examples of unsaturated carboxylic acids are those having 2 to 20 carbon atoms, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid or itaconic acid. The functional derivatives of these acids include, for example, the anhydrides, the ester derivatives, the amide derivatives, the imide derivatives, and the metal salts (eg, the alkali metal salts) of unsaturated carboxylic acids.

Unsaturated dicarboxylic acids with 4 to 10 carbon atoms and their functional derivatives, in particular their anhydrides are graft monomers which are particularly preferred. These graft monomers include e.g.

Maleic acid, fumaric acid, itaconic acid, citraconic acid, allyl succinic acid, 4-cyclohexene-1,2-dicarboxylic acid, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid, bicyclo (2,2,1) hept-5-en-2, 3-dicarboxylic acid, x-methylbicyclo (2,2,1) hept-5-ene-2,3-dicarboxylic acid, maleic anhydride, Itaconic anhydride, citraconic anhydride, allyl succinic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, 4-methylene-4-cyclohexene-l, 2-dicarboxylic anhydride, Bicyclo (2,2,1) hept-5-ene-2,3-dicarboxylic anhydride and x-methyl-bicyclo (2,2,1) hept-5-ene-2,2-dicarboxylic anhydride. Becomes advantageous Maleic anhydride used.

For grafting a graft monomer Various known ones can be applied to the mixture of (C1) and (C2) Procedure can be used. For example, This can be done by heating the polymers (C1) and (C2) at high temperature, about 150 ° C to 300 ° C, in the presence or in Absence of a solvent be carried out with or without a radical generator.

In the way mentioned above obtained graft-modified mixture of (C1) and (C2) the amount of grafting monomer can be selected appropriately, preferably between 0.01 to 10%, more preferably between 600 ppm and 2%, relative to the weight of the grafted (C1) and (C2). The Amount of grafted monomer is determined by the fact that the succinic Functions are studied by FTIR spectroscopy. The MFI of the co-grafted (C1) and (C2) is between 5 to 30 g / 10 min (190 ° C - 2.16 kg), preferably between 13 and 20.

Advantageously, the mixture of co-grafted (C1) and (C2) is such that the ratio of MFI ₁₀ / MFI _{2 is} greater than 18.5, with MFI _{10 designating} the flow rate at 190 ° C under a load of 10 kg and MFI ₂ the flow rate under a load of 2.16 kg. Advantageously, the MFI _{20 of} the blends of co-grafted polymers (C 1) and (C 2) is less than 24. MFI ₂₀ denotes the flow rate 190 ° C under a load of 21.6 kg.

As regards the second embodiment of the invention, the proportions (by weight) are advantageously as follows:
60 to 70% polyamide,
20 to 30% polypropylene,
From 3 to 10% of a polyolefin resulting from the reaction of a polyamide (C4) with a copolymer (C3) comprising propylene and a grafted or copolymerized unsaturated monomer X.

The MFI of the polypropylene is advantageously less than 0.5 g / 10min (230 ° C - 2.16 kg) and preferably between 0.1 and 0.5. Such products are in EP 647,681 described.

The grafted product of this second embodiment The invention will now be described. At the beginning, (C3) is prepared, which is either a copolymer of propylene and an unsaturated one Monomer X or a polypropylene is an unsaturated one Monomer X is grafted. X is an unsaturated monomer associated with the Propylene can be copolymerized or grafted onto the polypropylene can be and has a functional group with a polyamide can react. This functional group may e.g. a carboxylic acid dicarboxylic acid anhydride or an epoxide. As examples of monomers X, (meth) acrylic acid, maleic anhydride and unsaturated Epoxides, e.g. Glycidyl (meth) acrylate may be mentioned. Becomes advantageous Maleic anhydride used. As far as the grafted polypropylenes are concerned, X may be grafted onto polypropylene homo- or copolymers, such as e.g. Ethylene-propylene copolymers containing predominantly propylene (in moles). Advantageously (C3) is designed such that X grafts is. Grafting is a process known per se.

(C4) is a polyamide or a polyamide oligomer. Polyamide oligomers are in EP 342,066 and FR 2 291 225 described. The polyamides (or oligomers) (C4) are the products of the condensation of the above-mentioned monomers. Mixtures of polyamides can be used. PA-6, PA-11, PA 12, the copolyamide containing units are advantageous 6 and units 12 (PA-6/12) and the caprolactam, hexmethylenediamine and adipic acid based copolyamide (PA-616.6). The polyamides or oligomers (C4) may contain acid, amine or monamine ends. In order for the polyamide to contain a monoamine finish, it is sufficient to use a chain terminator of the formula R ₁ -NH | R ₂ , in which:
R _{1 is} hydrogen or a linear or branched alkyl group having up to 20 carbon atoms,
R _{2 is} a group having up to 20 linear or branched alkyl or alkenyl carbon atoms, a saturated or unsaturated cycloaliphatic radical, an aromatic radical or a combination of the former The limiting agent may be, for example, laurylamine or oleylamine.

Advantageously (C4) is a PA-6, a PA-11 or a PA-12. The proportion by weight of C4 in C3 + C4 is advantageously between 0.1 and 60%. The reaction of (C3) with (C4) is preferably in the molten state stood executed. For example, (C3) and (C4) can be mixed in an extruder at a temperature generally between 230 and 250 ° C. The average residence time of the molten material in the extruder may be between 10 seconds and 3 minutes, and preferably between 1 and 2 minutes.

Concerning the third embodiment, the proportions (by weight) are advantageously as follows:
60 to 70% polyamide,
5 to 15% of an ethylene-alkyl (meth) acrylate maleic anhydride copolymer.

The rest is a polyethylene of the Type LLDPE, VLDPE or metallocene; advantageous is the density of this polyethylene between 0.870 and 0.925 and the MFI between 0.1 and 5 (190 ° C - 2.16 kg).

Advantageously, the ethylene-alkyl include (meth) acrylate maleic anhydride Copolymers between 0.2 to 10% by weight maleic anhydride up to 40% by weight and preferably 5 to 40% by weight of alkyl (meth) acrylate. Your MFI is between 2 and 100 (190 ° C - 2.16 kg). The alkyl (meth) acrylates have already been described above. The melting point is between 80 and 120 ° C. These copolymers are commercially available. You are being radical-mediated Polymerization produced at a pressure of between 200 and 2500 can be bar.

Concerning the fourth embodiment, the proportions (by weight) are advantageously as follows:
According to a first variant:
60 to 70% of the mixture of polyamide and a copolymer comprising polyamide blocks and polyether blocks,
5 to 15% of an ethylene-alkyl (meth) acrylate-maleic anhydride copolymer.

The rest is a polyethylene of the Type LLDPE, VLDPE or metallocene, its density advantageously between 0.870 and 0.925 and its MFI between 0.1 and 5 (190 ° C - 2.16 kg) lies.

Advantageously, the ethylene-alkyl include (meth) acrylate maleic anhydride Copolymers between 0.2 to 10% by weight of maleic anhydride, up to 40% by weight and preferably 5 to 40% by weight of alkyl (meth) acrylate. Your MFI is between 2 and 100 (190 ° C - 2.16 kg). The alkyl (meth) acrylates have already been described above. The melting point is between 80 and 120 ° C. These copolymers are commercially available. You are being radical-mediated Polymerization produced at a pressure of between 200 and 2500 can be bar.

According to a second variant:
40 to 95% of a blend of polyamide and a copolymer containing polyamide blocks and polyether blocks,
60 to 5% of a mixture of an ethylene-alkyl (meth) acrylate-maleic anhydride copolymer and an ethylene-alkyl (meth) acrylate-glycidyl methacrylate copolymer.

The copolymer with the anhydride was defined in the first variant. The ethylene / alkyl (meth) acrylate / glycidyl methacrylate Copolymer may be up to 40% by weight, preferably between 5 and 40% by weight, of alkyl (meth) acrylate and up to 10% by weight of unsaturated epoxide, preferably 0.1 to 8%. Advantageously, the alkyl (meth) acrylate is methyl (Meth) acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate and 2-ethylhexyl acrylate selected. The amount of alkyl (meth) acrylate is preferably between 20 and 35%. The MFI is advantageously between 5 and 100 (in g / 10 minutes at 190 ° C below 2.16 kg) and the melting point is between 60 and 110 ° C. This Copolymer can be prepared by radical-mediated polymerization of the monomers to be obtained.

• – tertiäre Amine wie z.B. Dimethyllaurylamin, Dimethylstearylamin, N-Butylmorpholin, N,N-Dimethylcyclohexylamin, Benzyldimethylamin, Pyridin, 4-Dimethylaminopyridin, 1-Methylimidazol, Tetramethylehtylhydrazin, N,N-Dimethylpiperazin, N,N,N',N'-Tetramethyl-1,6-Hexandiamin, eine Mischung aus tertiären Aminen mit 16 bis 18 Kohlenstoffatomen, die unter dem Namen Dimethylallowamin bekannt ist,
• – tertiäre Phosphine wie z.B. Triphenylphosphin,
• – Zink-Alkyldithiocarbamate,
• – Säuren.

To accelerate the reaction between the epoxide and anhydride functions, catalysts can be added. Of the compounds which can accelerate the reaction between the epoxide and anhydride functions, the following are particularly mentioned:

• Tertiary amines such as dimethyllaurylamine, dimethylstearylamine, N-butylmorpholine, N, N-dimethylcyclohexylamine, benzyldimethylamine, pyridine, 4-dimethylaminopyridine, 1-methylimidazole, tetramethylehtylhydrazine, N, N-dimethylpiperazine, N, N, N ', N'-tetramethyl 1,6-hexanediamine, a mixture of tertiary amines containing 16 to 18 carbon atoms, known by the name dimethylallowamine,
• Tertiary phosphines such as triphenylphosphine,
• Zinc alkyldithiocarbamates,
• - acids.

The preparation of the mixtures of third layer can be carried out Be that different ingredients in the molten state be mixed in the apparatus, which is usually in the thermoplastic Polymer industry is used.

The first location may be from one location consist of fresh HDPE and a layer of recycled polymers, those from the manufacturing committee of the transport or storage devices or of those already mentioned non-compliant devices as per stand obtained by the technique. This recycled location is on the Side of the binder layer. In the following text these two Layers for the sake of simplicity by the term "first layer" designated.

The thickness of the first layer can be between 2 and 10 mm, the second layer between 30 and 500 um and that of the third layer between 30 μm and 2 mm. The total thickness is usually between 3 and 10 mm.

A binder layer can also be between the second and third layers are inserted. As examples of binders can the functionalized polyolefins (B1) described above can be mentioned. The binder between the first and second layers and the binder between the second and third position may be identical or different his. Described in the below descriptions of binders the term "polyethylene" is both homopolymers as well as copolymers; Such products were mentioned earlier in the Polyolefins of the third layer described.

As a first example of a binder can the above in the first preferred embodiment of the third layer mentioned mixture of co-grafted (C1) and (C2).

• – 95 bis 70 Teile eines Polyethylens (E) mit einer Dichte zwischen 0,910 und 0,930,
• – wobei die Mischung (D) und (E) derart ist, dass: seine Dichte zwischen 0,910 und 0,930 liegt, der Anteil von gepfropfter unsaturierter Carboxylsäure zwischen 30 und 10.000 ppm liegt, der MFI (ASTM D 1238 -190°C – 2,16 kg) zwischen 0,1 und 3g/10 Minuten liegt. Der MFI bezeichnet den Fließgeschwindigkeitsindex.

As a second example of a binder, mixtures may be mentioned which include:
5 to 30 parts of a polymer (D) which in turn comprises a mixture of a polyethylene (D1) having a density between 0.910 and 0.40 and a polymer (D2) selected from elastomers, very low density polyethylenes and metallocene polyethylenes wherein the mixture (D1) + (D2) is co-grafted with an unsaturated carboxylic acid;

• 95 to 70 parts of a polyethylene (E) with a density between 0.910 and 0.930,
• Wherein the mixture (D) and (E) are such that: its density is between 0.910 and 0.930, the proportion of grafted unsaturated carboxylic acid is between 30 and 10,000 ppm, the MFI (ASTM D 1238 -190 ° C - 2, 16 kg) is between 0.1 and 3 g / 10 minutes. The MFI refers to the flow rate index.

The density of the binder is advantageously between 0.915 and 0.920. Advantageous are (D1) and (E) LLDPEs and preferably have the same comonomer. This Comonomer can be selected be from 1-witches, 1-octene and 1-butene.

• – 5 bis 30 Teile eines Polymers (F), der seinerseits eine Mischung eines Polyethylens (F1) mit einer Dichte von zwischen 0,935 und 0,980 und einem Polymer (F2) umfasst, der ausgewählt ist aus Elastomeren, Polyethylenen sehr geringer Dichte und Ethylencopolymeren, wobei die Mischung (F1) + (F2) mit einer ungesättigten Carboxylsäure co-gepfropft ist,
• – 95 bis 70 Teile eines Polyethylens (G) mit einer Dichte zwischen 0,930 und 0,950,
• – wobei die Mischung von (F) und (G) derart ist, dass: seine Dichte zwischen 0,930 und 0,950 und vorteilhaft zwischen 0,930 und 0,940 liegt, der Gehalt von gepfropfter ungesättiger Carboxylsäure zwischen 30 und 10.000 ppm liegt, der gemäß ASTM D 1238 bei 190°C – 21,6 kg gemessene MFI (Schmelzindex) zwischen 5 und 100 liegt.

As a third example of a binder, mixtures may be mentioned which include:

• From 5 to 30 parts of a polymer (F) which in turn comprises a mixture of a polyethylene (F1) having a density of between 0.935 and 0.980 and a polymer (F2) selected from elastomers, very low density polyethylenes and ethylene copolymers, wherein the mixture (F1) + (F2) is co-grafted with an unsaturated carboxylic acid,
• 95 to 70 parts of a polyethylene (G) having a density between 0.930 and 0.950,
• Wherein the mixture of (F) and (G) is such that: its density is between 0.930 and 0.950 and advantageously between 0.930 and 0.940, the content of grafted unsaturated carboxylic acid is between 30 and 10,000 ppm, which is in accordance with ASTM D 1238 190 ° C - 21.6 kg measured MFI (melt index) is between 5 and 100.

As a fourth example of a binder may mention a polyethylene which is grafted with maleic anhydride, an MFI of 0.1 to 3, has a density between 0.920 and 0.930 and between 2 and 40% by weight in n-decane at 90 ° C insoluble Contains substances. To the proportion of insoluble in n-decane Determining substances, the grafted polyethylene at 140 ° in n-decane solved, the solution is cooled to 90 ° C and Precipitate products out; the mixture is then filtered and the portion is insoluble Component; is the percentage by weight which fails and by filtration at 90 ° C is collected. If the proportion is between 2 and 40%, points the binder has a good resistance to fuel.

The grafted polyethylene becomes advantageous dissolved in a non-grafted polyethylene, in such a way that the Binders a mixture of 2 to 30 parts of a grafted Polyethylene having a density of between 0.930 and 0.980 and of 70 to 98 parts of a non-grafted polyethylene with a Density between 0.910 and 0.940, preferably between 0.915 and Is 0.935.

As a fifth example of a binder, there can be mentioned mixtures comprising:
50 to 100 parts of a polyethylene homo- or copolymer (J) having a density greater than or equal to 0.9,
0 to 50 parts of a polymer (K) selected from polypropylene homo- or copolymer (K1), poly (1-butene) homo- or copolymer (K2) and polystyrene homo- or copolymer (K3),
wherein the amount of (J) + (K) is 100 parts, the mixture of (J) and (K) is grafted with at least 0.5% by weight of a functional monomer,
and this grafted mixture is itself diluted in at least one polyethylene homo or copolymer (L) or in at least one polymer of elastomeric type (M) or in a mixture of (L) and (M).

According to one embodiment of the invention, (J) is an LLDPE having a density of 0.91 to 0.930, wherein the comonomer contains between 4 and 8 carbon atoms. According to one another embodiment of the Invention is (K) a HDPE, which advantageously has a density of at least 0.945 and preferably between 0.950 and 0.980.

Advantageous is the functional Monomer maleic anhydride and its content is between 1 and 5% by weight of (n + (K).

Advantageously, (L) is an LLDPE, in which contains the comonomer between 4 and 8 carbon atoms and its Density preferably at least 0.9 and more preferably between Is 0.910 and 0.930.

Advantageous is the amount of (L) or (M) or (L) + (M) between 97 and 75 parts per 3 to 25 parts (J) + (K), wherein the amount of (J) + (K) + (L) + (M) is 100 parts.

As the sixth example of a binder can Mixtures mentioned are made of a polyethylene of the type HDPE, LLDPE, VLDPE or LDPE, 5 to 35% of a grafted metallocene polyethylene and 0 to 35% of an elastomer, the sum being 100%.

• – wenigstens ein Polyethylen oder ein Ethylen-Copolymer,
• – wenigstens ein Polymer, welcher ausgewählt ist aus Polypropylen oder einem Propylen-Copolymer, Poly(1-Buten) Homo- oder Copolymer, Polystyren Homo- oder Copolymer und vorzugsweise Polypropylen, wobei diese Mischung mit einem funktionellen Monomer gepfropft ist und diese gepfropfte Mischung selbst optional mit wenigstens einem Polyolefin oder wenigstens einem Polymer von elastomerer Natur oder einer Mischung derselben verdünnt ist. In der obigen gepfropften Mischung, stellt Polyethylen vorteilhaft wenigstens 50 % der Mischung und vorzugsweise 60 bis 90 Gew.% der Mischung dar.

As a seventh example of a binder, there can be mentioned mixtures comprising:

• At least one polyethylene or one ethylene copolymer,
• - At least one polymer which is selected from polypropylene or a propylene copolymer, poly (1-butene) homo- or copolymer, polystyrene homo- or copolymer and preferably polypropylene, said mixture is grafted with a functional monomer and this grafted mixture itself optionally diluted with at least one polyolefin or at least one polymer of an elastomeric nature or a mixture thereof. In the above grafted mixture, polyethylene is advantageously at least 50% of the mixture, and preferably 60 to 90% by weight of the mixture.

Advantageous is the functional Monomer selected from carboxylic acids and their derivatives, acid chlorides, Isocyanates, oxazolines, epoxides, amines or hydroxides, and preferably unsaturated Dicarboxylsäureanhydriden.

• – wenigstens ein LLDPE oder VLDPE Polyethylen,
• – wenigstens ein Elastomer auf der Basis von Ethylen, der ausgewählt ist aus Ethylen-Propylen Copolymeren und Ethylen-Buten Copolymeren,
• – wobei diese Mischung aus Polyethylen und einem Elastomer mit einer ungesättigten Carboxylsäure oder einem funktionellen Derivat dieser Säure gepfropft ist,
• – diese co-gepfropfte Mischung optional mit einem Polymer verdünnt ist, der ausgewählt ist aus Polyethylen Homo- oder Copolymeren und Styrenblockcopolymeren, wobei das Bindemittel (a) einen Ethylengehalt nicht unter 70 mol%, (b) einen Anteil an Carboxylsäure oder seiner Derivate von 0,01 bis 10 Gew.% des Bindemittels, und (c) ein MFI₁₀/MFI₂ Verhältnis von 5 bis 20 aufweist, bei welchem MFI₂ der Massen-Schmelzindex bei 190°C unter einer Last von 2,16 kg ist, der gemäß ASTM D 1238 gemessen ist, und MFI₁₀ der Massen-Schmelzindex bei 190°C unter einer Last von 10 kg, gemessen bei ASTM D 1238, ist.

As an eighth example of a binder, mixtures may be mentioned which include:

• At least one LLDPE or VLDPE polyethylene,
• At least one ethylene-based elastomer selected from ethylene-propylene copolymers and ethylene-butene copolymers,
• Wherein said mixture of polyethylene and an elastomer is grafted with an unsaturated carboxylic acid or a functional derivative of said acid,
• - This co-grafted mixture is optionally diluted with a polymer selected from polyethylene homopolymers or copolymers and styrene block copolymers, wherein the binder (a) has an ethylene content not less than 70 mol%, (b) a proportion of carboxylic acid or its derivatives of 0.01 to 10% by weight of the binder, and (c) has an MFI ₁₀ / MFI ₂ ratio of 5 to 20, in which MFI _{2 is} the mass melt index at 190 ° C under a load of 2.16 kg, measured according to ASTM D 1238 and MFI _{10 is} the mass melt index at 190 ° C under a load of 10 kg as measured by ASTM D 1238.

• – Füllstoffe (Mineralfüllstoffe, flammenhemmende Füllstoffe, etc.),
• – Faserstoffe,
• – Farbstoffe,
• – Pigmente,
• – optische Aufheller,
• – Antioxidanten,
• – UV Stabilisatoren.

The various layers of the structure of this invention, including the binder layers, may also contain at least one of the following additives:

• Fillers (mineral fillers, flame retardant fillers, etc.),
• - fibrous materials,
• - dyes,
• - pigments,
• - optical brighteners,
• - antioxidants,
• - UV stabilizers.

[Examples]

The following products were used:
EVOH D: ethylene-vinyl alcohol copolymer with 29 mol% ethylene,
MFI 8 (210 ° C - 2.16 kg), mp 188 ° C, crystallization temperature 163 ° C, Tg (glass transition temperature) 62 ° C.

The blends for the third layer were off Polyamide and polyolefin produced, known as Orgalloy®, and were made from the following products:

Polyamides (A)

PA 1: Copolyamide 6 / 6-6 of medium viscosity with a melting point of 196 ° C and a melt index of 4.4 g / 10 minutes according to ASTM 1238 at 235 ° C under one Weight of 1 kg.

PA 2: Copolyamide 6 / 6-6 of medium viscosity with a melting point of 196 ° C and a melt index of 6.6 g / 10 minutes according to ASTM 1238 at 235 ° C under one Weight of 1 kg.

Polyolefins (B2)

LLDPE: Linear polyethylene lower Density with a density of 0.920 kg / 1 according to ISO 1872/1 and a melt index of 1 g / 10 minutes according to ASTN 1238 at 190 ° C weighing 2.16 kg.

HDPE: High density polyethylene with a density of 0.952 kg / 1 according to ISO 1872/1 and a melt index of 0.4 g / 10 min according to ASTM 1238 at 190 ° C under a weight of 2.16 kg.

Polyolefins (B1)

B 1-1: This is a carrier PE with a content of 3000 ppm of maleic anhydride and a melt index 1 g / 10 minutes according to ASTM 1238 at 190 ° C weighing 2.16 kg.

antioxidants

• Anti 1: antioxidant of the handicapped phenolic type.
• Anti 2: secondary Antioxidant of the phosphite type.

The copolyamide, the polyolefin and the functional polyolefin are fed via three independent weighing devices (or simply by dry premixing the various granules) into the funnel of a co-rotating Werner-Pfleiderer twin screw extruder with a diameter of 40 mm, L / D = 40 (9 cylinders ("Sleeves") and 4 struts, ie a total length of 10 cylinders. The total flow rate of the extruder is 50 kg / h and the speed of rotation of the screws is 150 rpm and the material temperatures for the cylinders 3/4, 6/7 and 7/8 and at the nozzle outlet are 245, 263, 265 and 276 ° C, respectively , The extruded bars are granulated and then oven-dried at 80 ° under vacuum for 8 hours. The compositions are given in Table 1 below (parts by weight): TABLE 1

Orgalloy ^® 1: mixture of polyamide 6 and of polyolefin corresponding to the third preferred embodiment of the third layer and (by weight) is composed of:
65 parts PA6,
25 parts of a linear low density polyethylene with an MFI of 0.9 g / 10 minutes and a density of 0.920,
10 parts of a copolymer of ethylene, of butyl acrylate and of maleic anhydride in proportions by weight of 91/6/3 and MFI of 5 (190 ° C - 2.16 kg).

The binders described in the section "Second Example of a Binder" are designated Binder 2a - Binder 2d and their details are given in Table 2 below.

Other currently preferred embodiment

How best in 4 shows a further preferred embodiment of a multi-layer fuel tank 50 plastic tank wall 52 on, which has six layers of polymer material. From the outside of the tank inside, the fuel tank has an outer layer 54 on, which is preferably formed from HDPE, an intermediate layer 56 , which is preferably formed from recovered and re-milled material, an adhesive layer 59 , a locked position 60 , which is preferably formed from EVOH, another adhesive layer or Dämferlage 62 , and an inner situation 64 , Which is preferably formed from a polyamide or a mixture or an alloy of polyamide and polyolefins such as ORGALLOY ^®, generally, a composition may have as described above. Also, the HDPE, the reground, the adhesion, the dampers and the EVOH layers may also be of the above-described compositions.

The HDPE may have FINATHENE® MS201 with a density of the order of about 0.950. The adhesive and adhesive / damping layers 58 and 62 may be of a linear low density Maleinanhydridpolyethylen, such as that available under the trade name OREVAC ^® 18334 polyethylene. The blocked position 60 an EVOH copolymer may be, such as the product sold under the trade name SOARNOL ^® DT2903 copolymer sold by Atofina in Europe and Soarus in the United States.

The re-milled situation 56 is preferably reclaimed and re-milled scrap material and thus a mixture of different materials containing the fuel tank 50 form. If necessary, to be compatible with the HDPE outer layer 54 To obtain the reproduced can be diluted with HDPE, so that the re-milled position 56 has no ORGALLOY ^® matrix. Advantageously, when the regrind mass is diluted, an excess of re-massed mass can be produced which can be used for other applications, such as various valve bodies, carriers or other arrangements where the ORGALLOY® or nylon-based matrix is beneficial can, for example, due to their increased resistance to the penetration of hydrocarbon vapor.

Between the spenlage 60 and the inner situation 64 is a damper position 62 to improve the mechanical integrity of the fuel tank, as may be tested by various impact tests known in the art. The damper layer 62 may, although not necessarily, be made of the same material as the adhesive layer 58 although it is not necessary to provide an adhesive between the ORGALLOY and EVOH layers as these will adhere to each other by themselves. It has been found that one may degrade the structural integrity of the fuel tank at least some designs by allowing the ORGALLOY ^® and connects EVOH layers directly to each other, since the ORGALLOY ^® position does not take up the impact energy sufficient to the relatively fragile and thin EVOH To protect the situation. Therefore, the disposed between the EVOH and the ORGALLOY ^® location damper layer is primarily designed to dissipate energy and thereby increase the structural integrity of the fuel tank against Aufprälle or collisions.

For ease of processing and to improve compatibility with existing extrusion and blow molding tools, the various layers may have thicknesses similar to those in a conventional six-layer fuel tank comprising an outer layer of HDPE, a layer of remelted mass adjacent to the outer layer Adhesive layer between the layer of re-ground mass and a screed of EVOH and a further adhesive layer between the Spenlage and an inner layer of HDPE has. In view of the large capital cost of extrusion and blow molding equipment for fuel tanks, it is desirable that the equipment currently used to make conventional six-layer fuel tanks also be able to use the described multi-layer fuel tank 50 manufacture. Accordingly, the, inner situation 64 from ORGALLOY ® 30% of the total thickness of the fuel tank wall 52 make out, the damper position 62 in the order of 5% of the thickness of the fuel tank wall, the Spenlage 60 can be 3% of the total thickness, the adhesive layer 58 can 3% of the total thickness, the location 56 Of regrinded mass can make up about 40% of the total thickness and the outer layer 54 about 19% of the total thickness. Of course, these thicknesses illustrate only a presently preferred embodiment, and may be changed as desired within the scope of the present tools, or may be further changed as new or different tools are used. Through experiments, it was found that the hydrocarbon-spanning properties of the ORGALLOY® layer 64 Do not significantly change over a range of about 10% to 40% of the thickness of the fuel tank wall, provided the design of the fuel tank 50 is flexible. Are desirably the ORGALLOY ^® material may be through the same extrusion equipment as conventional six-layer fuel tank extruded which is suitable for polyethylene, so that the processing and manufacturing of the multilayered fuel tank 50 is very flexible and can be easily adapted to today's processing machines with the same tools, without requiring a large conversion.

If the multi-layer fuel tank 50 is constructed in the manner described above, it shows an outstanding hydrocarbon sponge ice as compared with conventional six-layer fuel tanks tung. This is to a large extent on the ORGALLOY ^® inner layer 64 which, in turn, is an outstanding hydrocarbon penetration donor and is significantly more resistant to hydrocarbon permeation than HDPE. The fuel tank thus has a first Spenlage, the inner ORGALLOY ^® position 64 includes, and also has a second Spenlage with the EVOH Spenlage 60 on. These layers 60 . 64 are arranged in series, thus significantly improving the overall resistance of the fuel tank 50 against the penetration of hydrocarbons. Both the EVOH Spenlage 60 as well as the inner ORGALLOY ^® layer 64 are at least substantially continuous and thereby reduce or eliminate the penetration windows in the fuel tank 50 ,

As in 5 is even shown in the area of the squeeze line 70 a blow molded fuel tank 50 the inner situation 64 continuous, indicating the penetration of hydrocarbon vapor along the squeeze line 70 significantly reduced. Blow molded fuel tanks are formed by placing a preform into a blow mold, closing the mold, and inflating the preform into the mold. When the mold is closed, the preform also closes and a squeezing line forms where the preform has been closed between the molds. With conventional six-layer fuel tanks, the permeability along the squeeze line is a problem because the EVOH sizing in the area of squeezing is not continuous. Since the EVOH spall layer does not seal itself in the conventional six-layer fuel tanks in the area of crushing, a penetration window is defined in the gap between parts of the sponge layer, allowing hydrocarbon vapors to escape more easily. The multi-layer fuel tank described here is, even if between the Spenlage 60 a similar window or gap exists (as in 5 shown schematically), no corresponding window or a corresponding gap in the inner layer 64 so that the extent of hydrocarbon penetration through the squeeze line 70 is greatly reduced. It is currently believed, without wishing to be bound by any particular theory or numerical range, that it is estimated that 20 to 30% of the hydrocarbon emissions from conventional six-layer fuel tanks are through the area of the squeeze line. Thus, the continuous inner layer decreases 64 in the fuel tank 50 even in the area of the squeeze line 70 strongly the hydrocarbon emissions from the fuel tank 50 ,

As in 5 shown, indicates the inner ORGALLOY ^® location 64 a different rheology than the inner layer of HDPE from conventional six-layer fuel tanks. Desirably, the inner ORGALLOY® provides location in the area of squeeze line 70 a flat inner surface throughout 62 that greatly reduces or eliminates problems that can occur with a conventional six-layer fuel tank. In conventional six-layer fuel tanks, the flow of material during the squeezing operation is relatively unpredictable and difficult to control. It is normal for a notch or depression to form on the inner surface of the HDPE inner layer in the area of the pinch line. This notch can reduce the structural integrity of the fuel tank against such things as internal pressure, which can result in breakage or cracking around the notch. Empirical data has shown that the multi-layer fuel tank 50 exhibits greater mechanical performance, including resistance to internal pressure, as evidenced by a significant improvement in the fuel tank burst test. Some empirical tests to date show that the fuel tank 50 in the order of 20 to 35% greater resistance to internal pressure than the conventional six-layer fuel tank. The rheology of the ORGALLOY® sheet, which has a lower viscosity than polyethylene, not only forms a continuous, relatively smooth inner surface 72 but also does not affect the thickness or integrity of the EVOH spine in the area of the squeeze line 70 to the extent that is found in conventional six-layer fuel tanks. You want to achieve that spenlage 60 of the multi-layer fuel tank in the area of the squeezing line 70 not as thin as conventional six-layer fuel tanks. This leads to even further improved resistance to penetration of hydrocarbon vapors, even in the area of the squeeze line 70 of the multi-layer fuel tank 50 ,

The resistance to hydrocarbon permeation greatly improved over conventional six-layer fuel tanks allows the multi-layered fuel tank 50 To meet the extremely stringent emission standards that are in force or are being considered in the state of California, for example. These standards include LEV II and PZEV, which require greatly reduced vehicle emissions. Although the construction of some conventional six-layer fuel tanks could meet the requirements of LEV II, it will not meet the requirements of the more restrictive PZEV guidelines. The multi-layer fuel tank 50 The disclosed embodiment provides significantly higher resistance to hydrocarbon permeation and can be readily designed to meet PZEV requirements. As regards the barrier performance of various materials in polymeric fuel tanks for non-alcoholic fuels or low-alcohol fuels such as CARB PhII, if HDPE were assigned a general permeability rate of 1000, ORGALLOY® would have a transmittance rate of approximately 1.5, more than 600, in approximate numbers - less than the quota for HDPE. For comparison, EVOH would have a permeability rate of 0.6. Thus, one sees that ORGALLOY ® alone is a vastly better barrier to hydrocarbon emissions than HDPE. Although nylon based and therefore somewhat prone to alko non-greasy fuels, ORGALLOY ® still offers much better resistance to hydrocarbon permeability than HDPE. Using similar general quotas, HDPE can have a permeability rate of 1000 for high-alcohol fuels such as the TF1 test fuel containing 10% ethanol while ORGALLOY® has a permeability rate of only about 225%. As a result, ORGALLOY ® has a more than four times lower permeability rate than HDPE, even for high-alcohol fuels.

If the fuel tank is designed in the manner described above, the overall resistance to hydrocarbon permeability of the multi-layer fuel tank is 50 for non-alcoholic or low-alcohol fuels of the order of 2½ to 3 times better than conventional six-layer fuel tanks. Expressed in approximate relative numbers, when assigning a permeability rate of 100 to the conventional six-layer fuel tank for such fuels, the multi-layered fuel tank 50 a permeability rate in the order of 30 to 40 on. Furthermore, the multi-layer fuel tank 50 For high-alcohol fuels such as TF1, the permeability rate is about half that of conventional six-ply plastic tanks. When a conventional six-layer fuel tank has a permeability rate of 100 for high-alcohol fuels, the multi-layered fuel tank 50 has a transmittance rate of about 45 to 55 for comparison. Further, test results have shown that the multi-layered fuel tank 50 has a transmittance rate of about 45 to 55 for comparison. Furthermore, test results have shown that the multi-layer fuel tank 50 CARB Ph II can deliver significantly reduced emissions of approximately 4 to 7 mg / day with an average of approximately 5 mg / day, and TF 1 provides 7 to 10 mg / day with an average of approximately 8 mg / day. These results are from an 80-week soak test at 40 ° C with 70-liter fuel tanks. The tanks had a surface area of about 2.1 m ² and a squish length of about 2 meters. Under similar test conditions with conventional similar sized fuel tanks, the transmission rates for conventional six-layer fuel tanks were more than twice that for CAB Ph II fuel and typically over 60% higher at TF1. It is believed that the permeability rate will not change significantly over the intended life of the fuel tank of 15 years or more.

Desirably, the multi-layer fuel tank dramatically reduces emissions of the largest soils commonly called aromatics. Typical aromatics include, but are not limited to, benzene, toluene, ethyltoluene, xylene and heavy aromatics. Even for fuels with high alcohol content, the emission of aromatics is the multi-layer fuel tank 50 only 1/10 of the emission of conventional six-layer fuel tanks, while the overall transmission rate of the multi-layer fuel tank 50 about half the size of a conventional six-layer fuel tank. Accordingly, the emission of the largest contaminants in the multi-layer fuel tank 50 considerably reduced. The emission of alkanes and oxygenates is also the multi-layer fuel tank 50 significantly reduced.

Because the inner ORGALLOY ® location 64 provides a consistent, thick and continuous internal barrier layer, is resistance to hydrocarbon permeability in the multi-layered fuel tank 50 from tank to tank, very consistent from day to day and month to month. In the processing and formation of the multi-layer fuel tank 50 There are very small deviations. In contrast, in the conventional six-layer fuel tank, variations in the thickness of the EVOH layer in any part of the fuel tank can drastically deteriorate its performance with respect to hydrocarbon permeability. Since EVOH is relatively expensive and brittle, it is important to control the thickness of the EVOH throughout the fuel tank. The conventional six-layer fuel tanks rely almost entirely on the EVOH layer for their resistance to penetration of hydrocarbons. Accordingly, while some conventional six-ply fuel tanks may be designed to meet some of the increasingly stringent emission standards, it is unlikely that all or even a significant number of conventional six-ply fuel tanks will be defective due to processing deviations including equipment, environment, human impact and the like meet these increased standards in a given manufacturing period.

Furthermore, the inner ORGALLOY ® has location 64 and the multi-layer fuel tank 50 in general, higher mechanical performance at higher temperatures compared to HDPE and to fuel tanks using an inner layer of HDPE, as in conventional six-layer fuel tanks. The inner ORGALLOY ® layer 64 has a significantly higher melting point, generally in the range of about 190 ° C to 204 ° C (375 ° F to 400 ° F), than that of HDPE, which has a melting point in the range of about 124 ° C to 135 ° C (255 ° F) ° F to 275 ° F). Thus, learns the multi-layer fuel tank 50 less bending of its walls 52 As the temperature increases, it reduces or eliminates the risk of the internal situation 64 is melted by returned to the fuel tank 50 even very hot fuel, such as from a fuel rail. For example, in some diesel fuel systems, the fuel may be recycled at temperatures up to 124 ° C (255 ° F), which is in the range of the melting point of HDPE, thereby melting the HDPE or its structural integrity, at least locally and intermittently, influence negatively. In contrast, fuel returned at temperatures of 124 ° C (255 ° F) can not significantly degrade the inner ORGALLOY® layer 64 cause it has a much higher melting temperature. The structural integrity of the multi-layer fuel tank 50 as measured for example by impact tests is also better than that of conventional six-layer fuel tanks, at least in certain temperature ranges, especially at higher temperatures. Because the multi-layer fuel tank 50 shows improved structural integrity is a potential for reducing the thickness of the fuel tank wall 52 available, which saves weight and costs.

Although the fuel tank construction described herein has been generally described with reference to a blow molded fuel tank having a squeeze line, it may also be used to advantage in a thermoforming operation wherein two halves of a fuel tank are generally separately formed and then joined together, eg, by welding. The inner ORGALLOY ® layer 64 is still continuous because the inner layer of one half of the tank is welded together with the inner layer of the other half of the tank to reduce or prevent permeability windows. In a thermoformed tank, the weld line extends around the entire circumference because the fuel tank is formed in two separate halves. Accordingly, this weld line between the two tank halves may be a significant source of hydrocarbon emissions in conventional thermoformed fuel tanks. This source of hydrocarbon emissions can be greatly reduced or eliminated when constructing the fuel tank in the manner described above, since permeability windows are at least partially reduced or eliminated, and the continuous inner layer is of a material which permits hydrocarbon permeation through the tank walls 52 greatly delayed.

The invention is not limited to the embodiments described above, for example, the outer layer 54 from HDPE may not be necessary if the re-milled layer 56 nylon-based matrix, as the HDPE and re-ground layers may not be compatible. To facilitate welding of other components to the outer layer nylon matrix (if the outer HDPE layer is not used), such as vent valves or the flange of a fuel pump module, these components may be formed of a nylon-based material. Further, although the can Spenlagen the last-described embodiment of EVOH and ORGALLOY ^® are formed, other materials are used. The EVOH may be removed or replaced with other materials resistant to hydrocarbon permeation and, moreover, the inner layer may be formed of a polyamide or other blend of polyamide and polyolefin as ORGALLOY. As another example, this may be with respect to the sponge layer 60 described EVOH material can be replaced by another polyamide or a mixture of polyamide and polyolefin, such as ORGALLOY ^® . This may be particularly desirable when the multilayer fuel tank to be filled with non-alcoholic fuels or fuels with a low alcohol content, because materials such as polyamide or blends of polyamide and polyolefin such as ORGALLOY ^® are a great spene to hydrocarbon permeation, rule particularly non alkoholi fuels. As another example, the multi-layer fuel tank 50 instead of blow molding and thermoforming by any other method such as overmolding with polyethylene or the like, in which a film is formed with layers of hydrocarbon barrier material. Of course, no matter which method is used to form the fuel tank, other materials suitable for a particular application may be used.

Claims (11)

Fuel tank with a tank wall, which the Interior of the fuel tank surrounds, with the tank wall an inner Layer of a mixture of polyamide and polyolefin adjacent to has the interior of the fuel tank and a Spenlage, the essentially surrounds the inner layer, and at least one structural layer, which surrounds the Spenlage. A fuel tank according to claim 1, wherein the tank wall is formed from a multilayer preform, which in its final form is blow-molded and has a pinch line in a region, in which the preform during the blow molding process is closed, the inner layer so is designed that part of the inner layer into another Part of the inner layer intervenes when the preform is squeezed is going to be a continuous inner layer of the tank wall without one Transmittance window to build. Fuel tank according to one of the preceding claims, the in addition one between the Spenlage and the at least one structural layer arranged adhesive layer comprises. Fuel tank according to one of the preceding claims, the a further arranged between the inner layer and the Spenlage damper position includes. Fuel tank according to one of the preceding claims, at which the inner layer has a continuous inner surface, which is designed to be in contact with fuel in the fuel tank to stand. Fuel tank according to one of the preceding claims, which an outer layer, a Spenlage, one between the outer layer and the Spenlage arranged adhesive layer, an inner layer of a mixture of polyamide and polyolefin adjacent to the interior of the fuel tank, and one between the spine layer and the inner layer damper position contains. A fuel tank according to claim 6, wherein the adhesive layer and the damper position are made of the same material. Fuel tank according to one of the preceding claims, the also one between the outer layer and the backlash arranged reposted layer comprises. A fuel tank according to claim 8, wherein the re-ground Location between the outer location and the adhesive layer is arranged. A fuel tank according to claim 8 or 9, wherein the re-ground layer has a nylon-based matrix. A fuel tank according to claim 8 or 9, wherein the re-ground layer comprises a polyethylene-based matrix.