DD247911A5 - Weatherproof plasticizer-free film especially for motor vehicles - Google Patents

Abstract

The invention relates to a plasticizer-free film, in particular for the interior and exterior of motor vehicles and a method for their preparation. The aim of the invention is to provide such uncrosslinked and thermoformable film with good mechanical properties, such as tensile strength, high Keltflexibilitaet, impact strength, heat distortion resistance and weather resistance. According to the invention, the film consists of 65 to 25 wt .-% of a partially crystalline ethylene-propylene-diene terpolymer with 65 to 82 wt .-% ethylene 18 to 35 wt .-% propylene 3 to 8 wt .-% ter component and 0 to 10 wt .-% fillers, such as chalk, kaolin, talc, soot, silica u. as well as 100 parts by weight of said plastics, 0.1 to 1.0 part by weight of stabilizers such as hindered phenolic antioxidants and the like. a.0.1 to 2.0 parts by weight lubricant such as metal salts of carboxylic acids u. From 0 to 5 parts by weight of colorant 0 to 4 parts by weight of aliphatic extender oils From the film according to the invention it is possible with advantage to produce a deformable composite film of EPDM / PP film with a crosslinked polyolefin foam layer. Fig. 1

Description

Field of application of the invention

The invention relates to a weather-resistant, plasticizer-free, uncrosslinked and thermoformable film, in particular for use in the interior and exterior of motor vehicles, based on ethylene-propylene-diene terpolymers, homo- and / or copolymers of propylene and optionally fillers and conventional Additives made by extruding or calendering with a film thickness of about 0.2 to 3 mm, and a method for producing such films.

Characteristic of the known technical solutions

For the interior trim and equipment of motor vehicles, such as side panels, crash pads, dashboards, headrests, sky or on external surfaces as corrosion protection soft PVC films are still used today. However, soft PVC films have the disadvantage that the plasticizer swells or evaporates over time and leaves unwanted fittings, for example on the windshields, which must be removed again and again. Furthermore, the content of polyvinyl chloride is disadvantageous, since there is a risk of the formation of corrosion-promoting hydrogen chloride due to the high exhaust gas temperatures when the film in the region of the exhaust system and the engine. Also occurs due to the loss of plasticizer occurring over time, an embrittlement of the film, which adversely affects their functionality and durability, especially at minus temperatures.

In DE ^ OS 2806726 a trained as Dröhnschutz protective layer for motor vehicle floors is described, which is a carrier layer based on polyolefins, in particular ethylene-propylene rubber, and at least 30 wt .-% preferably at least 70Gew .-% fillers based on bitumen, softening substances as it contains oils and acoustically active minerals like talc, slate, graphite, mica. This mostly soft plastic and soundproofing

The high filler contents of this film, however, reduce the strength of the film and favor in calendered films the so-called white fracture. Since the films of both applications are deformed onto the body parts, whitening is in any case undesirable for optical reasons. The protection against stone chipping is not sufficient for this protective layer. Blends of uncrosslinked ethylene-propylene sequence polymers with isotactic polypropylene have become known from DE-O 2732969, which can be processed, for example, by molding or extruding into shaped articles such as bumpers, seat shells, veneers, dashboards, spoilers, switch panels, steering wheel sheathing and ski shoes , However, depending on the composition, these blends either do not have sufficient cold flexibility or sufficient heat resistance.

From DE-OS 2742910 a thermoplastic elastomer mixture of 25 to 85 wt .-% of a substantially amorphous ethylene-propylene copolymer and 15 to 75Gew .-% of a crystalline block copolymer of propylene is known, which is particularly well for the production of cable sheathing and bumpers suitable for motor vehicles. However, as stated in DE-OS 2821342, the thermoplastic elastomer mixtures of DE-O 2742910 in terms of hardness, tensile strength, better resistance to high temperatures certainly in need of improvement, for a number of applications, and are for example in these properties by a Molding material and moldings produced therefrom according to DE-O 2821 342 exceeded.

In DE-O 2821 342 thermoplastic elastomer mixtures containing 30 to 75 parts of crystalline isotactic propylene homopolymer and 25 to 70 parts of a substantially amorphous rubbery ethylene-propylene polymer and a maximum of 15 parts of polyethylene which proportionally replace the propylene homopolymer are described , Although these mixtures have partly improved properties compared with binary molding compounds, it has been found that the mechanical properties of the elastomer mixtures known from DE-OS 2821342, in particular with regard to impact strength, tensile strength and low-temperature flexibility, are in need of improvement for extreme stresses. This is particularly due to the used in the substantially amorphous rubbery ethylene-propylene polymers. On the other hand, higher crystalline EPDM or EPM rubbers, which are to be referred to as partially crystalline, with a crystallization temperature (DSC maximum temperature) from / above 24 ° C than for the applications specified in DE-OS 2742910 and 2821342 evaluated as unsuitable.

From the company magazine "The Arc" of CHW Hüls, September 1974, No. 174, pages 18 to 22, the use of ethylene-propylene rubber both for injection molded parts for use in the automotive industry as well as for roofing films u.a. Known.

Object of the invention

The aim of the invention is to increase the utility value properties of such films in a cost-effective manner.

Explanation of the essence of the invention

The invention has for its object to provide a weather-resistant, plasticizer-free, uncrosslinked and thermoformable film, which is suitable for use in the interior and exterior of motor vehicles and the characteristic of this application high stresses both in terms of mechanical properties, such as tensile strength, high low-temperature flexibility , Impact resistance and heat distortion resistance, weatherability, and a method for producing the film.

The invention proposes a film based on a thermoplastic elastomer mixture which is characterized by a content of 65 to 25% by weight of a semicrystalline ethylene-propylene-diene terpolymer with 65 to 82% by weight of ethylene, 18 to 35% by weight of propylene, 3 to 8Gew .-% tercomponent with a melt index MFI (230/5) of 0.5 to 2.0 g / 10 min, a tensile strength of at least 10N / mm ² and a DSC peak temperature of mindestens4O ⁰ C, 35 bis75Gew. % Propylene homopolymer and / or propylene copolymer having a melt index MFI (230 / 2.16) less than 2 g / 10 min but not less than 0.2 g / 10 min, 0 to 10 wt% fillers, such as circles, kaolin, talc, carbon black, silica, silicic anhydride or the like, or mixtures thereof, as well as 100 parts by weight of the aforementioned plastics

0.1 to 1.0 parts by weight of stabilizers ^ hindered phenolic antioxidants, phenolic phosphites,

Thioester aliphatic carboxylic acids, 0.1 to 2 parts by weight of lubricants, such as metal salts of carboxylic acids, montan acid esters, hydrogenated

Hydrocarbon resins 0 to 5 parts by weight of colorant

0 to 4 parts by weight of aliphatic and / or naphthenic extender oils.

The filler-free or virtually filler-free film of ethylene-propylene-diene terpolymer (EPDM) and polypropylene according to the invention fulfills a bundle of property requirements which also ensure the long service life and functionality required in the field of motor vehicle applications. The film according to the invention can be processed by deformation processes, such as thermoforming process, vacuum forming, or cold forming to desired molding. The film according to the invention is distinguished in particular by the properties listed below:

1. very good stone chip resistance

2. good cold resistance

3. high tensile strength and elongation

4. high tear propagation resistance

5. low moisture sensitivity

6. good abrasion resistance

7. adequate gasoline resistance

8. good light and weather resistance

9. matte surfaces suitable for embossing

10. good contractibility

11. Temperature resistance of a molded part of the film, i. good heat resistance

12. no shrinkback under sunlight of a molded part of the film

13. no white fracture of the film during deformation

14. Preservation of the film also during and after deformation

15. Corrosion protection.

The film according to the invention is therefore particularly suitable for the interior and exterior of motor vehicles, since it has good strength values with good weather resistance and service life both at high temperatures and at low temperatures and also has high resistance to abrasion, stone chipping and similar mechanical superficial stresses

The film can also be produced in a corresponding coloring and can be formed individually or in combination with other materials to form corresponding parts due to their good deep drawability in a variety of forms.

The inventively selected and used for the film semi-crystalline ethylene-propylene-diene terpolymers having a very high tensile strength or tensile strength, preferably of at least 15 N / mm ² , whose degree of crystallinity is correlated with the DSC maximum temperature and at least about 40 ⁰ C. , in the preferred range at least about 43 ^° C., in conjunction with the selected polypropylenes, allow the production of the film by calendering or extrusion having the properties described.

In particular, ethylidene norbornene is suitable as the terpolymer, but also dicyclopentadiene.

Since the extent of crystallinity also correlates with the ethylene content as well as with the tensile strength, in a preferred embodiment of the invention ethylene-propylene-diene terpolymers having an ethylene content of at least 70% by weight are used.

The semicrystalline EPDM's have the processing technology advantage over the amorphous and almost amorphous EPDMs in that they are obtained in crumbly form and can also be pelletized and therefore can be easily metered and mixed and therefore processed directly on continuously operating mixing machines.

The amorphous rubbers, however, are rubbery and are in lump or ball shape and are not pelletizable without additives.

The DSC maximum temperature of the EPDM's is determined with the differential scanning calorimeter, as well as the heat of crystallization. The latter is also a measure of the degree of crystallinity. The heat of crystallization of the ethylene-propylene-diene terpolymers used according to the invention should be about at least 15cal / g.

The propylene homopolymer and / or propylene copolymer used are preferably those having a melt index MFi (230 / 2.16) of less than 2 g / 10 min, preferably less than 1 g / 10 min, but not less than 0.2 g / 10 min. These are in particular selected propylene homopolymers, random propylene copolymers, block propylene copolymer with 5 to 20 wt .-% copolymerized ethylene, which have a particularly low melt index. These selected polypropylenes, together with the ethylene-propylene-diene terpolymers used, enable good processing into films by calendering, which is a particularly economical process or else by extrusion. Here, films having a thickness of about 0.2 to 1.0 mm are preferably produced by calendering, while films in thicknesses of about 0.7 to 3 or more millimeters can be produced by extrusion. It is also possible to make thinner films thicker by laminating or duplicating calendered and / or extruded films. Since polypropylene adheres very strongly, it is extremely difficult to calender polypropylene while avoiding sticking to the calender rolls. Also, in order to avoid this sticking of the polypropylene during calendering, close process parameters of the specified type are to be observed. Here, the selection of stabilizers and lubricants is important. When making the film by calendering, however, it should be noted that polypropylene with an MFI (230 ° C / 21.6 N) less than 0.1 g / 10 min is no longer suitable for use, as can no longer be sufficient calendering.

In order to prevent the degradation of the polymers during plasticizing and calendering or extrusion and at the same time to allow very high processing temperatures, stabilizers and anti-aging agents for polyolefins, in particular based on sterically hindered phenolic antioxidants, phenolic phosphites, thioesters of aliphatic carboxylic acids, optionally mixtures thereof but in relatively small quantities.

For example, there are used as stabilizers pentaerythritol tetra-jS-S 1 -di-t-butyl-hydroxyphenylpropionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol) distearyl pentaerythritol diphosphite and 2,6-di-t-butylbenzyl. butyl-4-methylphenol in question.

In particular, metal salts of carboxylic acids, such as calcium soaps, calcium stearate, zinc stearate and, in particular, montanic acid esters and / or hydrogenated hydrocarbon resins are added as lubricants for the processing.

Other auxiliaries, such as flame retardants, UV absorbers can be contained in the film.

The compositions used in the invention can be processed very surprisingly well, even lighter than z. B. only polypropylene calendered or extruded films.

Since fillers generally reduce the strength properties of the film, fillers are added in the novel film only in small amounts, which may be on the one hand to inorganic powdery fillers such as chalk, talc, lime or kaolin or preferably also to so-called reinforcing fillers such semi-active or active carbon blacks, silica, silicic anhydride, glass fibers, or mixtures of the aforementioned fillers. Even mica or barite can be provided in small quantities. The fillers should be very finely divided, so that they do not adversely affect the subsequent processing of the film by thermoforming or compression, etc., and also do not impair the surface quality. The fillers should not exceed a particle size, determined when passing through a 30 / xm sieve, but preferably below 20 to 10 / xm sieve.

It is of course also possible to add to the film for colorant, which, however, should also be very finely divided ig like the other fillers, so that they do not make adversely noticeable in a further processing or deformation of the film. As colorants, in addition to dyes, pigments, such as titanium dioxide, it is also possible to use carbon black in small amounts, which additionally has the advantage of increasing the weather resistance of the carrier layer. In this case, even small amounts in the carrier layer are sufficient.

In addition, in view of the processability of the ethylene-propylene polymers used, elasticizing substances may also be added in minor amounts below ~4 parts by weight, based on 10 parts by weight of polymer, such as aliphatic and / or naphthenic extender oils.

A preferred embodiment of the film according to the invention with high elastomer contents, which has particularly good properties in the cold, such as high impact strength, is characterized by a content of

60 to 40% by weight of ethylene-propylene-diene terpolymer 40 to 60% by weight of homo and / or copolymer of propylene 0 to 6% by weight of fillers

'And on 100Gew.-parts of the aforementioned plastics

0.1 to 1.0 parts by weight of stabilizers, such as hindered phenolic antioxidants, phenolic phosphites,

Thioester aliphatic carboxylic acids, 0.1 to 2 parts by weight of lubricants, such as metal salts of carboxylic acids, montan acid esters, hydrogenated

Hydrocarbon resins Obis5Gew.-parts Colorant

0 to 4 parts by weight of aliphatic and / or naphthenic extender oils,

wherein the film in the longitudinal direction has a tensile strength of at least 20 N / mm ^2, preferably 25 to 28 N / mm ² and an elongation at break of at least 450%, preferably of at least 550% and a cold impact value after VDCh of at least -50T.

For such applications in the motor vehicle, in which no extreme low-temperature impact is required, for example in the interior, a somewhat harder adjusted film is proposed according to the invention, which is characterized by a content of

45 to 25% by weight of ethylene-propylene-diene terpolymer

75 to 55 wt .-% homo- and / or copolymer of propylene

0 to 6% by weight of fillers

and to 100 parts by weight of the aforementioned plastics

0.1 to 1.0 parts by weight of stabilizers ₍ such as sterically hindered phenolic antioxidants, phenolic phosphites,

Thioester aliphatic carboxylic acids, 0.1 to 2 parts by weight of lubricants, such as metal salts of carboxylic acids, montan acid esters, hydrogenated

Hydrocarbon resins 0 to 5 parts by weight of colorant

0 to 4 parts by weight of aliphatic and / or naphthenic extender oils

wherein the film in the longitudinal direction has a tensile strength of at least 24N / mm ² , preferably from 26 to 28 N / mm ² and an elongation at break of at least 450%, preferably at least 500%; an ethylene-propylene-diene terpolymer having a tensile strength of at least 15 N / mm ^{2 is} used; an ethylene-propylene-diene terpolymer having a DSC maximum temperature of at least 43 ° C is used; an ethylene-propylene-diene terpolymer having an ethylene content of at least 70% by weight is used; a propylene homopolymer and / or propylene copolymer having a melt index MFI {230 / 2.16) less than 1 g / 10 min is used; a propylene copolymer having an ethylene content of 5 to 20% by weight is used; Fillers having a maximum particle size, determined when passing through a 30 p.m sieve, preferably ΙΟμ, ιη sieve are used; a side with a layer of a cross-linked polyolefin foam, in which at least 15 wt .-%, preferably at least 20Gew .-% of a polar copolymerized polymer are contained in 100 parts by weight of polyolefin resin or resin mixtures, directly adherent thermally or flame-laminated ; the release force between PP / EPDM film and foam layer is at least 8N / 5cm, preferably more than 12N / 5cm, and in particular is higher than the inherent strength of the foam; As a polar copolymerized polymer butyl acrylate in an amount of at least 15 wt .-% based on the polyolefin resin or

resin mixture is provided; is provided as a polar copolymerized polymer vinyl acetate in an amount of at least 20Gew .-% based on the polyolefin resin or -harzgemisch.

The film of the invention is particularly well finished by embossing the surface in a dull or grained texture. This shows the quality of the material of the film, as in a subsequent deformation of the film, for. B. by vacuum forming, the embossing of the surface of the film is perfectly maintained. It is also possible to optionally print or varnish the surface of the film. This requires the use of suitable paints, such. B. two-component paints no special pretreatment of the film surface.

An essential property of the film according to the invention is its deep drawability, i. the possibility, in particular by hot deformation, such as deep drawing, or pressing, for example by means of vacuum against a corresponding shape or in a closed mold, to produce moldings from corresponding blanks of the film. The high flexibility of the film allows a high degree of deformation and thus a good adaptation to given shapes. However, the film according to the invention is also so largely flexible and deformable, of course, depending on the thickness that it can be applied at low desired degrees of deformation without deformation in the heated state by cold working on corresponding preformed parts. In any case, a made of the film according to the invention is characterized

Molded part by a high dimensional stability and heat resistance. It is also to be expected that in the production,

z. B. by calendering or extruding subsequently embossed surface of the film even in a hot deformation, such as deep drawing, their embossing maintains due to the good heat resistance of the film.

For the interior of a motor vehicle, for example, molded parts such as side panels, door inner panels, armrests, tunnel covers, dashboards, sky can be made entirely or partially from the film of the invention. It is also possible to connect the film with other films or textile textile fabrics, to laminate or to process, for example, crash pads or backfoaming for example with polyurethane foam.

In the exterior of a motor vehicle, the film according to the invention can be applied and used directly or as a molded part as a protective cover.

An inventive method for producing the film of a composition according to the invention is characterized in that a mass ₍ containing

65 to 25 wt .-% of a partially crystalline ethylene-propylene-diene terpolymer with

65 to 82% by weight of ethylene

From 18 to 35% by weight of propylene

3 to 8% by weight of the component,

having a melt flow index MFI (230/5) of 0.5 to 2.0 g / 10 min, a tensile strength of at least 10 N / mm ² and a DSC maximum temperature of at least 40 ^° C .; 35 to 75% by weight of propylene homopolymer and / or propylene copolymer having a melt index MF! (230 / 2.16) less than 2g / 10min, but not less than 0.2g / 10min; 0 to 10% by weight of fillers such as chalk, kaolin, talc, carbon black, silica, silicic anhydride or the like, or mixtures thereof

as well as 100 parts by weight of the aforementioned plastics

0.1 to 1.0 part by weight of stabilizers ₍ hindered phenolic antioxidants, phenolic phosphites,

Thioesters of aliphatic carboxylic acids, 0.1 to 2 parts by weight of lubricants, such as metal salts of the carboxylic acid, Montansäüreester, hydrogenated

Hydrocarbon resins Obis5Gew.-parts Colorant

0 to 4 parts by weight of aliphatic and / or naphthenic extender oils,

which has a melt index MFI (230/5) of about 0.8 to about 8, preferably 1 to 6g / 10min, mixed with heating to a temperature of about 50 ⁰ C to about 80 ⁰ C and when exposed to higher temperatures of about 17O ⁰ C to 21O ⁰ C further plasticized and homogenized and on exposure to maximum temperatures of about 165 ° C to about 210 ⁰ C to films of a thickness of 0.2 to about 1.5 mm calendered or to films of a thickness of about 0.7 to 4mm at melt temperatures of 190 ⁰ C to 260 ⁰ C are extruded.

For the good processability of the molding composition for producing uniform void-free films by preferably calendering or extruding, the melt index (230/5) of the plastic composition is in the range from about 0.8 to about 10 g / 10 min, preferably in the range from 1 to about 6 g / 10min to choose. Since the selected semicrystalline EPDM's are in particulate form or can be prepared, the materials can be mixed in a simple manner, eg heating-cooling-mixer combination and metered and with the help of the usual equipment for plastics such as kneader or extruder or screw kneader at a melt temperature from 165 ° C to about 210 ⁰ C plasticized. This mass can be further plasticized and homogenized in a further second plasticizing step at higher temperatures, for example on rollers or in a strainer or to be fed to a calender. The calender should have at least four rolls which may be arranged in the known form such as I, L, F or Z. For calendering the films according to the invention, the calender rolls should have a slightly falling temperature seen in the working direction, wherein the two first feed rollers should have the highest temperature, preferably 190 ⁰ C to 23O ⁰ C, while the last calender roll to a 2O ⁰ C to 30 ⁰ C may have lower temperature, since it essentially serves the smoothing and calibration. The film according to the invention can be calendered at roll withdrawal speeds and thus production speeds of at least 10 meters per minute and more, depending on the thickness of the film. In the extrusion of the film according to the invention, the plasticization and shaping in an apparatus, that is carried out continuously in an extruder, whereby also the feed zone to the discharge zone, an increasing temperature gradient, starting at about 100 ⁰ C to a maximum of about 250 ⁰ C is provided. Very thick foils are called plates. In the production of the films by calendering or extrusion, it is possible to directly inline a surface embossing on a surface side of the film by the kaiandrierte film inline on a surface side at the melt temperature of 110 ⁰ C to 170 ⁰ C and an embossing roll temperature of 8O ⁰ C is embossed to 140 ⁰ C and an embossing pressure of 20 to 100 bar.

For the production of moldings z. B. as trim parts for a motor vehicle are produced from the film according to the invention according to the configuration of the desired molded part stamped blanks, which are then preheated to temperatures of 120 ⁰ C to about 170 ⁰ C and then deformed using pressure or vacuum to the desired shape , The film can be here perfect, ie deform without wrinkles and without white fracture. In particular, the deep-drawing methods, such as vacuum forming, the vacuum printing method with positive or negative mold, are used as the shaping method. The moldings produced in this way show a very good shape and an extremely good heat resistance

 The film can also be processed by blow molding the molding by means of overpressure.

The film of the invention can also be used with other fabrics to composite films or multilayer films z. B. be connected by lamination or by means of adhesion promoter. In particular, composites of the film with sheets or metal plates or foils show good resistance to corrosion resistance and rigidity with cold workability. Such PP-EPDM films laminated metal sheets have a wide field of application.

The film according to the invention can also be part of a multilayer film, and be joined, for example, to textile fabrics. For the interior of automobiles often non-slip and soft trim parts are desired, for example, by backing of soft PVC films with foam, especially soft PVC foam, so far produced. However, all materials which contain plasticizers adhere to the disadvantages explained at the outset, which occur due to the sweating out of the plasticizers. It is therefore desirable to use plasticizer-free but elastic foams for the interior of motor vehicles, such as crosslinked or uncrosslinked polyolefin foams, as described for example from DE-PS 1694130, DE-AS 1694194 or DE-AS 2417 557 u. a.

have become known. Since ordinary polyolefin, such as polyethylene, is nonpolar, it can not be directly or massively adhered to many materials, or only with insufficient adhesive strengths. without adhesion promoter, connect.

It has now surprisingly been found that the film according to the invention can be thermally or flame-laminated directly adherent with a crosslinked polyolefin foam, wherein in 100Gew.-parts polyolefin resin or polyolefin at least 15Gew .-%, preferably at least 20Gew .-% of a polar copolymerized polymer are included. The polyolefin resins suitable for use in the invention for the foam here include high, medium or low density polyethylene, ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-styrene copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid Copolymers, ethylene-acrylic acid ester copolymers, ethylene-acrylic acid salt copolymers, polybutene-1, propylene-butene copolymers or mixtures of two or more of these polymers.

It is also possible to replace minor amounts of the polyolefin resin with miscible rubbers or miscible plastics, but with the content of polar copolymerized polymer then being based on the total amount of resin

The miscible rubbers include natural rubber, ethylene-propylene rubber, butyl rubber, polyisobutylene, polybutadiene, polyisoprene and styrene-butadiene rubber.

The miscible plastics include acrylonitrile-butadiene-styrene resins, polystyrene, chlorinated polyethylenes, chlorinated polypropylenes, and chlorosulfonated polyethylenes.

The total amount of the rubber and / or the plastic; which are blended therewith is equal to or less than that of the polyolefin, and is preferably 10 to 46 parts by weight per 100 parts by weight of the polyolefin.

The crosslinked polyolefin foams used to make the polypropylene-ethylene-propylene-diene terpolymer film and foam layer composite film of the present invention are especially made by peroxide crosslinking with foaming with chemical blowing agents. However, physically crosslinked polyolefin foams may also be used, which then contain no crosslinking agent.

Suitable crosslinking agents are organic peroxides, such as dicumyl peroxide, di-tert-butyl peroxide, 1,3-bis (tert-butyl peroxiisopropyl) benzene,

2,5-dimethyl-2,5-di (tert-butylperoxy) hexane and

2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3;

Azide compounds such as

1,9-nonane-bis-sulfonazide and

1,7-heptane-bis (sulfonazide); and

Silicon-containing peroxide, such as silyl peroxide.

The crosslinking agent is selected so that it decomposes thermally at a temperature lower than the decomposition temperature of the blowing agent to be used.

The amount of the crosslinking agent depends on the type of the polyolefin and the blowing agent and the amount of the blowing agent, and is 0.01 to 3 parts by weight per 100 parts of the polyolefin.

The blowing agent has a decomposition temperature higher than the softening point of the polyolefin and also has a decomposition temperature higher than that of the crosslinking agent. It is used in an amount of 0.1 to 30 parts by weight per 100 parts of resin. The propellant closes, for example

azodicarbonamide,

-dinitrosopentamethylenetetramine,

barium,

Hydroazodicarbonamid,

p-Toluolsulfonylsemicarbacit and

Trihydrazine triazine.

Polyolefin, crosslinking agent and blowing agent are kneaded with mixing before thermal expansion. The kneading is usually carried out in a Henschel mixer, a mixing roll, a Banbury mixer or extruder. In doing so, care must be taken not to decompose the crosslinking agent and the blowing agent.

The resin composition is formed into sheets, sheets, particles, etc. by an extruder, a press, calender roll, etc. In this process step, it is important to avoid the decomposition of the crosslinking agent and the blowing agent as in the kneading process.

In the foaming process, the heating is usually carried out in one stage by raising the temperature to such a high level that the crosslinking agent and the blowing agent are decomposed. However, a two-stage heating process may also be employed such that first the crosslinking agent is decomposed and subsequently the blowing agent is decomposed by further temperature increases. The decomposition of the crosslinking and blowing agent can be carried out under heating under high pressure, and then the expansion can be carried out by reducing the pressure. Preshaped foamable particles can be foamed in a metallic mold into foamed products.

Plate-like foamable material can be continuously transferred to a foamed sheet by heating on a wire mesh conveyor in a hot air oven.

According to the invention it has been found that a high adhesive strength, which is measured as a release force according to DIN 53357, is achieved with such a polyolefin foam, in which polar copolymers, such as ethylene-butyl acrylate and / or ethylene-vinyl acetate are present in sufficient quantities , In particular, a crosslinked polyolefin foam having a butyl acrylate content greater than 9% by weight, preferably greater than 15% by weight, has been found to be particularly suitable for flame lamination with a PP / EPDM film. At high laminating speeds, separation strengths are obtained which are above the intrinsic strength of the foam used.

The invention can be realized with a polyolefin foam containing as polyolefin resin exclusively a polar copolymer, such as ethylene-butyl acrylate, ethylene ethyl acrylate or ethylene vinyl acetate, if sufficient contents of vinyl acetate and / or butyl acrylate and / or ethyl acrylate are included or mixtures of these copolymers with a polyethylene or another polyolefin, but in compliance with the above conditions. In particular, according to the invention it is possible to produce composite films in which the release force between PP / EPDM film and foam layer is at least 8 N / 5 cm, preferably more than 12 N / 5 cm and, in particular, higher than the inherent strength of the foam.

The degree of crosslinking of the polyolefin foam used is generally between 60 and 80%, depending on the process. The crosslinked polyolefin foams are also predominantly closed-cell, elastic foams. These give the composite film according to the invention made of PP / EPDM film and polyolefin foam layer a particularly soft feel of the composite. In addition, the composite film of the invention is characterized by a very good thermoformability, wherein the foam structure is retained. Also, the composite film is characterized by special lightweight, high impact strength and high impact strength. The filler-free or virtually filler-free film of polypropylene and ethylene-propylene-diene terpolymer according to the invention, in combination with the special adhesive foam layer, fulfills a bundle of property requirements which ensure a high service life and functionality in the motor vehicle application sector. For the composite film in particular foam layers in the range of about 2 to 20 mm are laminated with the PP / EPDM film, without a primer layer, either by flame laminating or by thermal lamination, wherein the layers to be joined together in each of the methods prematurely above the plasticizing temperature heated the plastic temperature and connected together. The Flammenkaschierung is carried out with devices known per se, wherein the speed of the Schaumstoffart and the foam thickness is dependent. Here, too, it can be seen that the acrylate-containing polyolefin foam is superior to the vinyl acetate-containing one, since in the former, good adhesion is achieved even at higher laminating speeds.

For the composite film in particular lightweight foams with densities of about 20 to 70, preferably from about 20 to 40 kg / m ³ are used.

A chemically crosslinked polyolefin foam is preferred for the composite film according to the invention, since it can be deformed sufficiently late by deep drawing or the like, even in conjunction with the PP / EPDM film. However, physically crosslinked polyolefin foams are also useful.

In the following examples, the preparation of the thermoplastic crosslinked polyolefin foam is carried out as described in DE-PS 1694130 by mixing and compounding the polymers with the blowing agent, the peroxide and any additives and then formed by an extruder into a homogeneous matrix. The foaming takes place directly or after intermediate storage in a heating oven at temperatures of 200 ⁰ C to 25O ⁰ C. The amount of blowing agent additive depends on the desired bulk density.

embodiment

The invention will be illustrated by the following examples.

The testing of the properties was carried out according to the following measuring characteristics:

Shore hardness D according to DIN 53505

- Tensile strength according to DIN 54355

Mooney viscosity determination according to ASIM-D1640

Melt index MFI according to DIN 53735

- Separation strength according to DIN 53357

- Heat resistance according to Vicat according to DIN 53460

- Tensile strength according to DIN53455

- Elongation at break according to DIN 53455

- yield stress DIN 53455

- Cold shock value after VDCh

Example 1: Production of the film

60 parts by weight of polypropylene copolymer having an ethylene content of 10% and an MFI (190/5) of 0.8 g / 10 min are mixed with 40 parts by weight of EPDM having a Mo'oney viscosity ML (1 + 4) 100 ° of 85, an MFI (230/5) of 0.8 g / 10min and an ethylene content of 67% by weight of a propylene content of 30% by weight and an ethylidene norbornene content of 3Gew% and a tensile strength of 16.3 N / mm ² and a DSC -Maximum temperature of 44 ⁰ C with 0.45 parts by weight of hindered Am in (Chimasorb® 944) and benzotriazole (Tinuvin® 327) as a stabilizer, 0.15 parts by weight of calcium stearate as a lubricant and 2 wt . Parts color (TiO ₂ ) processed in a Heizkühlmischer at 70 ⁰ C to a free-flowing mixture, plasticized and homogenized in a twin screw at temperatures up to 200 ⁰ C and fed to a rolling mill. From this, the mass is fed to a calender at a temperature of about 180-19O ⁰ C and pulled out to a film of 0.75 mm. At the outlet of the calender is an embossing device with which the desired surface structure at an embossing temperature of the embossing roller of about 11O ⁰ C and an embossing pressure of 40 bar is generated. The film has a tensile strength in the longitudinal extent of 28N / mm ² and elongation at break in the longitudinal extent of 635%, cold impact value of -55 ° C, Shore hardness D50

 The plasticized mass had an MFI (230/5) of 1.8g / 10min.

Example 2: Production of a film

47 parts by weight of the polypropylene copolymer mentioned in Example 1 are premixed with 53 parts by weight of the EPDM from Example 1 and the other slugs of Example 1 in a Heizkühlmischer at 70 ⁰ C, fed to a Zweiwellenkneter and plasticized at 170 ⁰ C to 18O ⁰ C. and brought to a rolling mill with temperatures of about 180 ⁰ C to 200 ° C. Via a strainer, the calender is charged with the mass plasticized to about 190 ^° C., which is calendered to give a film having a thickness of 0.8 mm, followed by embossing.

The 0.8 mm thick film has a tensile strength in the longitudinal direction of 26.5 N / mm ² and an elongation at break in the longitudinal direction of 650% and a longitudinal stretching tension of 10.6 N / mm ² , Shore hardness D of 49 and cold impact value after VDCh of

The MFI (230/5 of the mixture was 1.6g / 10min.

Example 3: Production of a film

As described in Example 2, a film is made by calendering. The thickness of the film was 0.3 mm, the tear strength was measured at 26 N / mm ² and the elongation at break at 670%. The cold impact value after VDCh was -55 ° C, the Shore hardness D48.

Example 4: Production of a film

42 parts by weight of a polypropylene homopolymer having a density of 0.9 g / ml and an MFI (190/5) of 0.7 g / 10 min are premixed with 58 parts by weight of the EPDM of Example 1 in a heating mixer , plasticized and homogenized in an internal mixer and fed to the calender via a rolling mill, drawn out to form a film of a thickness of 0.8 mm and embossed. The film has a tensile strength in longitudinal extension of 25 N / mm ² and an elongation at break in the longitudinal direction of 680%. The MFI (230 + 5) of the mixture was 1.5 g / 10 min.

Examples 5 to 13: Production of foams

The foams for lamination of the films produced in Examples 1 to 4 were prepared as follows:

In each case 100 parts by weight of the polyolefin or polyolefin mixture mentioned in Table 1 are homogeneously mixed with the amounts of azodicarbonamide and dicumyl peroxide also mentioned in Table 1, processed to a homogeneous granulate by plasticizing and converted to a matrix by subsequent extrusion. This matrix is processed in a circulating air oven at 225 ° C to a foam whose density was 30 kg / m ³ and whose thickness is shown in Table 1.

The matrix required for producing the foam according to example 6 was additionally laminated on one side with a 230 .mu.m, thick polyethylene film.

The approach of Example 7 contains no dicumyl peroxide, since the matrix was treated with 9Mrad electron beam before the foaming and thereby crosslinked.

Examples 5, 6, 7, 8, 11 are comparative examples.

Example 14: (comparison)

The produced in Example 2 polypropylene EPDM film of 0.8 mm thickness was connected to the flame laminating at a speed of 6.5 and 8.0m / min with the polyethylene foam produced in Example 5 the thickness of 10mm. The peel strength of the two substrates was measured as the release force according to DIN 53357. The release strength is listed in Table 2.

Example 15: (Comparison)

A composite ₍ as described in Example 14, prepared from the film Example 2 and the foam from Example 6, wherein the side of the foam covered with PE film was laminated with the PP / EPDM film. Table 2 included.

Example 16: (comparison)

A composite was prepared as described in Example 14 of the Example 2 film and the physically cured foam of Example 7 at 8.0 and 10.0 m / min laminating speed, respectively. Separation strengths can be found in Table 2.

Example 17: (comparison)

The film of Example 3 was flame-laminated with the 9 wt% vinyl acetate-containing foam of Example 8 at 8.0 and 10.0 m / min. The separation strengths are listed in Table 2.

Example 18:

A composite was made by flame lamination of the PP / EPDM film of Example 2 and the 15 wt .-% vinyl acetate-containing foam of Example 9 at 4.0; 6.5 and 8.0m / min. The measured separation strengths are included in Table 2.

Example 19:

The PP / EPDM film of Example 2 was flame-laminated with the 25 wt.% Vinyl acetate-containing foam of Example 10 at 6.5 and 8.0 m / min. The separation strengths are listed in Table 2.

Example 20: (Comparison)

A composite of PP / EPDM film of Example 2 and the polyethylene and EPDM containing foam of Example 11 was prepared by flame lamination at 8.0 and 10.0 m / min. The measured separation forces are shown in Table 2.

Step Example! 21:

The PP / EPDM film produced in Example 2 was flame-laminated with the foam of ethylene-butyl acrylate copolymer and polyethylene according to Example 12 at speeds of 8.0 and 10.0 m / min. A separation of the two substrates was no longer possible, since the foam previously tore. The measured values are in Table 2.

Example 22:

A composite of the PP / EPDM film of Example 2 and the 19 wt .-% butyl acrylate-containing foam of Example 13 by flame lamination at 8.0 and 10.0 m / min was prepared. A separation of the two substrates was no longer possible. The test values are listed in Table 2.

Example 23:

The PP / EPDM film produced in Example 1 was flame-laminated with the butyl acrylate-containing foam prepared according to Example 12 at 8.0 and 10.0 m / min and tested for release strength. Test values see table 2.

Example 24:

The PP / EPDM film produced in Example 4 was flame-laminated with the foam of Example 12 at 8.0 and 10.0 m / min.

Separation was not possible (see Table 2).

As can be seen from Table 2, no satisfactory adhesion values are obtained when flame lamination between a PP / EPDM film is attempted with a pure polyethylene foam (Example 14), a pure polyethylene foam whose top was previously laminated with a polyethylene film (Example 15), a pure physical crosslinked polyethylene foam (Example 16), a polyethylene foam containing only 9 weight percent vinyl acetate (Example 17), and an EPDM-containing polyethylene foam (Example 20).

Satisfactory adhesion is achieved in flame lamination with a 15 wt.% Vinyl acetate foam when laminated particularly slowly, but the economy is still very low (Example 18).

An improved economy through higher laminating speeds is achieved with a foam with 25 wt .-% vinyl acetate (Example 19).

Very good adhesion, even at high laminating speeds, is achieved with foams containing butyl acrylate, as demonstrated by Examples 21 to 23.

The invention is illustrated by way of example in the drawing. Show it

FIG. 1: View of a composite film

Figure 2: view of a deep-drawn molded part made of a composite film

In the figure 1, the structure of a composite film 1 is shown schematically. The film 2 consists essentially of a calendered or extruded plastic film based on EPDM and propylene homopolymer and / or propylene copolymer. This film 2, which may possibly be embossed on its upper side 5, is adhesively bonded on its underside to the foam layer 3. The composite film 1 shown in Figure 1 is deformed for example to form a part 1 a of FIG. 2. This deformation can be done for example by deep drawing, wherein the composite foil is preheated to a temperature of about 125 to 150 ⁰ C and then deformed by means of a vacuum against a mold. In this deformation, the top of the film 2 comes to rest against the mold.

But it is also possible to compress the composite film 1 according to Figure 1 under preheating by means of a molding press also to the desired shape.

Table 1

5 6 7 8th Examples 9 10 11 12 13 LD-PE (parts by weight) MFI (190 / 2,16) 100 2 100 2 100 2 - - 71 4 25 2 - Copolymer (parts by weight) MFI (190 / 2.16) Vinyiacetate content (wt%) Butyl acrylate content (wt%) - - MII 100 7 9 100 2.5 15 100 2.1 25 I I I 75 2 19 100 2 19 EPDM (parts by weight) - - - - - - 29 - - Azodicarbonamide (parts by weight) Dicumyl peroxide (parts by weight) 19 0.9 19 0.9 23 23 0.9 19 0.9 19 0.9 23 0.9 23 0.9 19 0.9 Matrix laminated with PE foil - + - - - - - - - -

Foam thickness (mm) 10 10 5 6 10 10 5 5 10

Table 2

Example no. Foam thickness (mm) Laminating speed (m / min) Release force (N / 5cm) 14 14 10 10 6.5 8.0 2,0 1,5 CJl CJl 10 10 6.5 8.0 2.4 * 1.5 CD CD 5 5 8.0 10.9 2.4 1.9 17 17 6 6 8.0 10.0 1.9 1.9 OO OO OO 10 10 10 4.0 6.5 8.0 > 25.0 *> 1.7> 1.8 19 19 10 10 6.5 8.0 > 27.2 * 4.4 20 20 5 5 8.0 10.0 5.3 2.5 NJ NJ 5 5 8.0 10.0 > 17.0 *> 16.5 * NJ NJ N) N) 10 10 8.0 10.0 > 26,0 *> 18,0 * 23 23 5 5 8.0 10.0 > 17.0 *> 17.0 * 24 24 5 5 8.0 10.0 > 17.0 *> 17.0 *

Separation force of the substrates is greater than the inherent strength of the foam. Hence demolition or splitting of the foam.

Claims (15)

Invention claim: 1. weather-resistant, plasticizer-free, uncrosslinked and thermoformable film, in particular for use in the interior and exterior of motor vehicles, based on ethylene-propylene-diene terpolymers, homopolymers and / or copolymers of propylene and optionally fillers and conventional additives, prepared by extrusion or calendering with a film thickness of about 0.2 to 3 mm, characterized by a content of 65 to 25 wt .-% of a semi-crystalline ethylene-propylene-diene terpolymer with 65 to 82% by weight of ethylene
From 18 to 35% by weight of propylene
3 to 8% by weight of the component, having a melt flow index MFI (230/5) of 0.5 to 2.0 g / 10 min, a tensile strength of at least 10 N / mm ² and a DSC maximum temperature of at least 40 ° C; From 35 to 75% by weight of propylene homopolymer and / or propylene copolymer having a melt index M Fl (230 / 2.16) less than 2 g / 10 min but not less than 0.2 g / 10 min; 0 to 10 wt. % Fillers, such as chalk, kaolin, talc, carbon black, silica, silicic anhydride or the like, or mixtures thereof, as well as 100 parts by weight of the aforementioned plastics 0.1 to 1.0 parts by weight of stabilizers, such as hindered phenolic antioxidants, phenolic phosphites, Thioesters of aliphatic carboxylic acids,
0.1 to 2 parts by weight of lubricant, such as metal salts of carboxylic acids, montan acid esters, hydrogenated Hydrocarbon resins
0 to 5 parts by weight of colorant 0 to 4 parts by weight of aliphatic and / or naphthenic extender oils. 2. film according to item 1, characterized by a content of 60 to 40% by weight of ethylene-propylene-diene terpolymer 40 to 60 wt .-% homo and / or copolymer of propylene 0 to 6% by weight of fillers and to 100 parts by weight of the aforementioned plastics 0.1 to 1.0 parts by weight of stabilizers ₍ such as sterically hindered phenolic antioxidants, phenolic phosphites, Thioesters of aliphatic carboxylic acids,
0.1 to 2 parts by weight of lubricant, such as metal salts of carboxylic acids, montanic acid esters, hydrogenated Hydrocarbon resins
0 to 5 parts by weight of colorant 0 to 4 parts by weight of aliphatic and / or naphthenic extender oils, wherein the film in the longitudinal direction has a tensile strength of at least 20 N / mm ^2, preferably 25 to 28 N / mm ² and an elongation at break of at least 450%, preferably of at least 550% and a cold impact value to VDCh of at least -5O ⁰ C. 3. film according to item 1, characterized by a content of 45 to 25 wt .-% ethylene-propylene-diene terpolymer
75 to 55% by weight of homo- and / or copolymer of propylene
0 to 6% by weight of fillers and to 100 parts by weight of the aforementioned plastics 0.1 to 1.0 parts by weight of stabilizers, such as hindered phenolic antioxidants, phenolic phosphites, Thioesters of aliphatic carboxylic acids,
0.1 to 2 parts by weight of lubricant, such as metal salts of carboxylic acids, montan acid esters, hydrogenated Hydrocarbon resins
0 to 5 parts by weight of colorant 0 to 4 parts by weight of aliphatic and / or naphthenic extender oils wherein the film in the longitudinal direction has a tensile strength of at least 24 N / mm ² , preferably from 26 to 28 N / mm ² and an elongation at break of at least 450%, preferably at least 500%. 4. A film according to any one of items 1 to 3, characterized in that an ethylene-propylene-diene terpolymer having a tensile strength of at least 15 N / mm ^{2 is} used. 5. A film according to any one of items 1 to 4, characterized in that an ethylene-propylene-diene terpolymer is used with a DSC maximum temperature of at least 43 ° C. A film according to any one of items 1 to 5, characterized in that an ethylene-propylene-diene terpolymer having an ethylene content of at least 70% by weight is used. 7. A film according to any one of items 1 to 6, characterized in that a propylene homopolymer and / or propylene copolymer having a melt index MFI (230 / 2.16) is less than 1 g / 10 min used. 8. A film according to any one of items 1 to 7, characterized in that a propylene copolymer having an ethylene content of 5 to 20 wt .-% is used. 9. A film according to any one of items 1 to 8, characterized in that fillers having a maximum particle size, determined when passing through a 30 / um sieve, preferably lO / xm sieve are used. 10. A film according to any one of items 1 to 9, characterized in that a side with a layer of a cross-linked polyolefin foam, wherein in lOOGew.-Teile Polyolefinharzbzw. Resin mixtures at least 15 wt .-%, preferably at least 20 wt .-% of a polar copolymerized polymer, are contained, directly adhesive or thermally flame-retardant. 11. A film according to item 10, characterized in that the release force between PP / EPDM film and foam layer is at least 8 N / 5 cm, preferably more than 12 N / 5 cm, and in particular is higher than the inherent strength of the foam. 12. A film according to item 10 or 11, characterized in that as a polar copolymerized polymer butyl acrylate in an amount is provided by at least loGew ^ based on the polyolefin resin or resin mixture. 13. A film according to item 10 or 11, characterized in that is provided as the polar copolymerized polymer vinyl acetate in an amount of at least 20 wt .-% ₍ based on the Polyolefinharzbzw-resin mixture. 14. A method for producing a film according to any one of items 1 to 9, characterized in that containing a mass From 65% to 25% by weight of a semi-crystalline ethylene-propylene-diene terpolymer having from 65% to 82% by weight of ethylene
From 18 to 35% by weight of propylene
3 to 8% by weight of the component, with a melt index MFI (230/5) of 0.5 to 2.0 g / 10min, a tensile strength of at least 10N / mm ² and a DSC peak temperature of at least 40 ⁰ C; From 35% to 75% by weight of propylene homopolymer and / or propylene copolymer having a melt index MFI (230 / 2.16)> less than 2g / 10min, but not less than 0.2g / 10mm; From 0 to 10% by weight of fillers, such as chalk, kaolin, talc, carbon black, silica, silicic anhydride or the like, or mixtures thereof, and to 100 parts by weight of the aforementioned plastics 0.1 to 1.0 parts by weight of stabilizers ^ hindered phenolic antioxidants, phenolic Phosphites, thioesters of aliphatic carboxylic acids, 0.1 to 2 parts by weight of lubricants, such as metal salts of carboxylic acids, montanic acid esters, hydrogenated Hydrocarbon resins
0 to 5 parts by weight of colorant 0 to 4 parts by weight of aliphatic and / or naphthenic extender oils, which has a melt index MFI (230/5) of from about 0.8 to about 8, preferably 1 to 6 g / 10 min. has, with heating to a temperature of about 5O ⁰ C to about 80 ⁰ C mixed and further plasticized and homogenized on exposure to higher temperatures of about 170 ⁰ C to 210 ⁰ C and upon exposure to maximum temperatures of about 165 ⁰ C bis about 210 ° C into films having a thickness of 0.2 to about 1.5 mm kalandriertoderzu foils having a thickness of about 0.7 to 4 mm at melt temperatures of 19O ⁰ C to 260 ⁰ C are extruded. 15. The method according to item 14, characterized in that the calendered film is embossed inline on a surface side at a melt temperature of 110 ⁰ C to 170 ⁰ C and an embossing roll temperature of 80 ⁰ C to 140 ⁰ C and an embossing pressure of 20 to 100 bar , For this 1 page drawings