WO1994025253A1

WO1994025253A1 - Short-fiber-reinforced plastic foils

Info

Publication number: WO1994025253A1
Application number: PCT/EP1994/001346
Authority: WO
Inventors: Gerhard Ströhle; Peter Gujer; Willy Arber; Mario Slongo
Original assignee: Sika Ag, Vorm. Kaspar Winkler & Co.
Priority date: 1993-04-29
Filing date: 1994-04-28
Publication date: 1994-11-10
Also published as: CZ330794A3; JPH08505182A; AU6649894A; CA2136720A1

Abstract

Flexible plastic foils reinforced with surface-treated short fibers of approximately 0.3 to 10 mm length, and their use mainly in roof and tunnel construction. Such flexible short-fiber-reinforced plastic foils have very good overall properties, mainly a high resistance to aging, high stress resistance and high mechanical and thermal stability and weather resistance.

Description

SHORT-FIBER-REINFORCED PLASTIC FOILS

FIELD OF THE INVENTION

The present invention relates to a flexible plastic foil reinforced with surface-treated short fibers, a process for its production and its use.

BACKGRQPKD OF THE INVENTION

Non-reinforced as well as reinforced plastic foils are used for the most diverse purposes in the field of

building materials (for example, see SIA [Swiss Engineers and Architects Association] Standard 280 (1983)).

However, non-reinforced plastic foils have disadvantages. For example, they can have high shrinkage values, they have a large thermal. expansion coefficient, some have a lack of working properties (for example in welding), and may have only a mediocre strength. The result of this is that their use, in particular in connection with sealing and insulation such as in roof and tunnel construction, is not quite satisfactory. For this reason it has been attempted to reduce these disadvantages by means of a reinforcement.

Reinforcement of the plastic materials can be provided, for example, by weaves, woven fabrics, or fleeces of synthetic and inorganic fibers. The purpose of these reinforcements is to improve the properties of the plastic materials. For example, lattice-reinforced plastic foils are used in the field of building materials, which consist of a woven fabric, weave or fleece between the bottom and top .layer of the foil. However, a reinforcement of this type requires an extensive production process, poses the danger of delamination and causes problems with covering the knots.

To reduce these disadvantages it has been proposed to embed short fibers in the plastic materials and to omit the conventional fabric reinforcement completely.

Plastic materials containing conventional short fibers are described for example by Th. F. Schuler in

"Kautschuk und Gummi- Kunststoffe" [Caoutchouc and Plastic Rubber], Vol. 45. No. 7, July 1992, pp. 548 - 549, in "Kevlar Short Fiber Reinforcement of Elastomer Matrices". US Patent 4,595,620 discloses a folded article made of short-fiber-reinforced plastic foil, and French Patent Publication FR-A- 2,507,123 describes a semi-finished product containing a thermoplastic matrix with polyamide pulp embedded therein, wherein a portion of the pulp can be partially replaced by mineral short fibers. However, all these reinforcements made with conventional short fibers do not satisfactorily result in the desired physical and chemical properties, in particular in connection with flexible plastic :foils such as are employed in roof and tunnel construction. In addition, adhesion problems between the short fibers and the jmatrix occur. An article entitled "Renforcement du PVC Souple par les Fibres Santoweb W" [Reinforcement of Flexible PVC by Santoweb W Fibers] in "Composites, Plastiques Renforcees, Fibres de Verre Textile" [Composites, Reinforced Plastics, Textile Glass Fibers], Vol. 25, No. 1, 1985, pp. 50 to 55 describes surface-treated cellulose fibers in a matrix of plasticized polyvinyl

chloride. However, this reference does not provide any information beyond this regarding: the employment of other surface-treated short fibers and their surface treatment.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide seals or insulations, in particular for uses in roof construction and tunnel construction, which do not have the above-mentioned disadvantages.

This object is attained in accordance with the invention by means of a reinforced plastic foil, the

reinforcement of which is based on surface-treated short fibers. It was surprisingly found that a plastic foil reinforced in this way can not only be employed in roof and tunnel construction, but also does not have any

disadvantageous properties in comparison with the known plastic foils mentioned above and instead is superior to them in some of its properties. These, and other objects, will be readily understood by one skilled in the art, as reference is made to the

following drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 illustrates an embodiment of the distribution of the short fibers in a foil (top view), and Fig. 2

illustrates an embodiment of the distribution of the short fibers in a cross section of a foil.

DETAILED DESCRIPTION

Thus, the invention relates to a flexible plastic foil reinforced with short fibers, distinguished in that it contains a surface-treated arbitrary short fiber embedded in a matrix made of a plastic material.

The plastic material of the matrix which encloses the surface-treated short fibers like an envelope can be an arbitrary homopolymer or copolymer of, for example, a

thermoplastic material, an elastomer, a thermoplastic

elastomer or a polymer blend. All these plastics are known and therefore can be produced in a known manner, for example a polyreaction such as polyaddition, polycondensation and polymerization and a polymer-analogous reaction.

Thermoplasts are understood to be plastic materials with a linear or branched structure. Cited as examples are homo-polymers such as polyethylene of low, medium or high density, and especially ultra-low density, low density

polyethylene with a linear structure, polypropylene, polyamide such as Nylon 11 and Nylon 12, polyester, polyvinyl chloride, especially plasticized polyvinyl chloride, poly-1-butene, poly-isobutylene, ionomers, polyvinylidene chloride,

polymethyl methacrylate, polyvinyl alcohol, polyvinyl acetate, as well as copolymers of styrene/acrylonitrile, styrene/acrylonitrile and butadiene, polyvinyl chloride/ethylene vinyl acetate, ethylene/acrylic acid ester, ethylene/vinyl acetate, propylene copolymerized with other α-olefins such as ethylene or butene, ethylene/propylene/1-butene, vinylidene chloride/vinyl chloride, methyl methacrylate/ethyl acrylate, as well as Nylon 6/Nylon 66.

Elastomers are generally understood to be slightly cross-linked plastics. Cited as examples are: olefinic elastomers, such as ethylene/propylene copolymer,

ethylene/propylene dien copolymer, an ethyl/vinyl acetate copolymer and an ethylene/ethyl acrylate copolymer,

furthermore natural and synthetic caoutchouc, styrene-butadiene caoutchouc, butyl caoutchouc, nitrile caoutchouc, fluoride-elastomer, polyaerylate,, polyurethane, silicon caoutchouc, polysulfide caoutchouc, chloroprene caoutchouc, chloro-sulfonated polyethylene and chlorinated polyethylene.

Thermoplastic elastomers are, for example, styrene-butadiene-styrene elastomer, styrene-ethylene-butene-styrene, thermoplastic polyurethane elastomer as well as thermoplastic polyester and polyamide elastomers and polyolefinic

thermoplastic elastomers, wherein the elastomer component can be present in partially linked form.

Finally, polymer blends. can be used, which are mixtures of different polymers. Mentioned by way of example are polyvinyl chloride/ethylene-vinyl acetate (mixture ratio approximately 9:l to 6:4), polyvinyl chloride/vinyl chloridevinyl acetate (mixture ratio approximately 9:1 to 3:7), polyvinyl chloride/chlorinated polyethylene (mixture ratio approximately 9:1 to 4:6) and polyvinyl chloride/polymethyl methacrylate (mixture ratio approximately 9:1 to 8:2).

A thermoplastic is the preferred matrix, in particular polyvinyl chloride (PVC), an ethylene vinyl acetate grafted with polyvinyl chloride (EVA-gPVC), and an ultra-low density polyethylene (ULD-PE).

The surface-treated short fibers are, for example, man-made fibers and textile fibers.

Man-made fibers include, for example, boron fibers, glass-ceramic fibers, glass fibers, rock fibers, slag wool or whiskers.

Textile fibers include, for example, aramide fibers, polyvinyl chloride fibers, polypropylene fibers, polyphenylene sulfide fibers, polyetherimide fibers, polyamide fibers, polyimide fibers, polyester fibers or cotton fibers. These may be, but need not be, molecularly or longitudinally

oriented.

All these short fibers have been surface-treated. This surface treatment forms a thin film on the fibers, which is retained on the short fibers in the matrix and which, among other things, is responsible for the good adhesion to the matrix, if necessary via a modifier. These treatments can be performed either chemically in a known manner, for example by impregnating with a treatment agent, or physically. If required, drying is subsequently performed.

Silane compounds, for example, such as amino silanes or epoxy silanes, or polyurethane or sugar compounds (for example dexol) are considered as chemical treatment agents (see, for example, in the series of documents of the firm DEGUSSA the No. 75 of Oct. 1987, entitled "Pigmente"

[Figments] or the brochure "Textilglas" [Textile Glass] of VETROTEX).

Etching of the fibers, for example, can be mentioned as a physical treatment which is used with carbon fibers and aramide fibers in particular, or metallizing or roughening of the fibers.

These fibers which are used as short fibers have a length of approximately 0.3 to 10 mm, mainly 1 to 6 mm, particularly 3 to 6 mm, a diameter of approximately 5 μm to 1 mm and in particular a fineness of approximately 8 to 14 μm.

The amount of surface-treated short fibers in the plastic foil lies between 1 to 40 weight-%, mainly 2 to 20 weight—% and particularly 2 to 16 weight-%.

This amount, and therefore the ratio of short fibers to the matrix, can vary as a function of the use made of the short fiber-reinforced plastic foil. For example, to obtain as high as possible a strength and a high module, more than 15% of short fibers are used. But if only improved

dimensional stability is required, less than 5% of short fibers are used. These amounts relate to the employment of glass fibers. If short fibers with a different module or different strength are used, which in addition have a

different adhesion to the matrix,, the amounts of short fibers can change.

The surface-treated short fibers are embedded in the matrix and are statistically distributed on the top, the bottom and in the center. They can be present by themselves or mixed with other surface-treated short fibers, such as textile fibers and metal fibers, or textile fibers and glass fibers. In the case of mixed fibers this is a hybrid

reinforcement.

The surface-treated short fibers embedded in the matrix are invisible as such to the naked eye.

The surface-treated short fibers are preferably present as individual fibers, particularly in view of the distribution.

The preferred fiber is a glass fiber.

By combining different materials (plastic material of the matrix and surface-treated short fibers), the physical properties of the individual components are exceeded.

In addition, the plastic foils reinforced with surface-treated short fibers can advantageously contain additives of an organic and/or inorganic nature.

Examples of such additives are:

a. Colorizing additives in amounts of approximately 0.1 to 15 weight-%, such as pigments, if colored short- fiber-reinforced plastic foils are desired, cited by way of example are inorganic pigments such as titanium oxide, iron oxide, lead chrornate, chromium oxide, carbon black and zinc oxide, as well as organic pigments such as chromium ophtale, azo pigments, dipyrolopyrole, naphthol- AS-pigments, phthalo-cyanine, quinacridone, derivates of perylene tetracarbonic acid, aminoanthraquinone and isoindoline pigments;

b. Plasticizers in amounts of approximately 25 to 40 weight-%, for example on the basis of phthalic acid, such as di(2-ethylheχyl)phthalate, diisooctyl phthalate, di(n-octyl)phthalate, di-n-alkyl phthalate, such as dimethyl phthalate, diethyl phthalate, di-propyl

phthalate, dibutyl phthalate, diisobutyl phthalate, butylbenzyl phthalate, dipentyl phthalate, dihexyl phthalate and diisoheptyl phthalate, diisononyl

phthalate, di(n-nonyl)phthalate, diisodecyl phthalate, diundecyl phthalate, diisotridecyl phthalate,

dicyclohexyl phthalate, diphenyl phthalate,

dimethoxyglycol phthalate, dibutoxylglycol phthalate and di(methylcyclohexyl) phthalate; furthermore plasticizers on the basis of adipic acid, such as butylbenzyl adipate, benzyl-2-ethylhexyl adipate, triisotridecyl adipate, di(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, dibutyl adipate, diisobutyl adipate,

dibutoxyethyl adipate, diisooctyl adipate and di-n-alkyl adipate; plasticizers on the basis of azelaiσ acid, such as di-2-ethylhexyl azelate, diisooctyl azelate and di-n-hexyl azelate; plasticizers on the basis of sebacic acid, such as dibutyl sebacate, dioctyl sebacate, dimethyl sebacate and diisodecyl sebacate; as well as plasticizers on the basis of phosphonic acid, such as trialkyl

phosphate, for example tributyl phosphate, tri(2-ethylbutyl) phosphate, tri(2-ethylhexyl) phosphate, trichloroethyl phosphate, 2-ethylhexyldiphenyl phosphate, cresyldiphenyl phosphate, triaryl phosphates such as triphenyl phosphate and arylalkyl phosphates, such as triisopropylphenyl phosphate and tricresyl phosphate; c. Fungicides in amounts of approximately 0.1 to 2 weight-%, such as 10,10-oxy-bis-phenoxyarsine, N-(trihalogenomethylthio)-phthalimide, diphenyl antimony-2-ethylhexanoate, copper-bis-(-3-hydroxy quinoline) and tributyl oxide and derivates;

d. Filler materials in amounts of approximately o.l to 50 weight-%, mainly mineral materials such as

carbonates and silicates, such as calcium, barium

sulfate, calcium sulfate and- aluminum hydroxide; e. Anti-oxidants of known types in amounts of approximately 0.05 to 3 weight-%, mainly of the type of sterically hindered phenols, secondary aromatic amines, thioether, phosphite and phosphonite;

f. Light-stabilizers in amounts of approximately 0.1 to 3 weight-%, such as o-hydroxyphenyl-benzotriazoles, o-hydroxyphenyl triazines and o-hydroxybenzophenones, as well as those of the type of sterically hindered amines (HALS);

g. Flame-retardants in amounts of approximately 0.1 to 60 weight-%, such as antimony trioxide, aluminum trihydrate, magnesium hydroxide and magnesium oxide, phosphoric acid ester, chloroparaffin,

dibromopentaerythritol, hexachlorocyclopentadiene, octabromodiphenyl ether, polydibromophenylene oxide and tetrabromobisphenol-A;

h. Stabilizers in amounts of approximately 1 to 5 weight-%, such as Ba/Zn, Ba/Cd, Ca/Zn stabilizers in the form of salts of organic acids and inorganic acids, such as Ba/Cd carboxylate and Ca/Zn carboxylate or substituted phenols; organotin stabilizers, aminocrotonic acid ester, 2-phenylindole, phenylurea, diphenylthio urea, Fb soaps, methyltin mercaptide, di-n-octyltin mercaptide and aminocarbonic acid ester;

i. Co-stabilizers in amounts of approximately 1 to 5 weight-%, such as organic phosphite, epoxidized fatty acid ester, such as epoxidized soybean oil, epoxidized castor oil, epoxidized linseed oil, epoxidized sunflower oil, also sorbin, trismethylol-propane, dipentaerythritol and pentaerythritol;

k. Modifiers in amounts of approximately 2 to 10 weight-%, such as glycidyl methacrylate (GMA), polymethyl methacrylate (PMMA), ethylene vinyl acetate (EVA), vinyl chloride/ethylene-vinyl acetate co-polymer, chlorinated polyethylene, aerylnitryl/butadiene/styrene graft

polymer, vinyl chloride/aerylester graft polymer, methylmethacrylate/butadiene/styrene graft polymer, α- methylstyrene/acrylnitrile (α-MS/AN), polyurethane (PU), EVA with reactive OH, polyolefins and polyolefin co- and terpolymers chemically modified with maleic acid

anhydride (HAH), and

1. Lubricants in amounts of approximately 0.1 to 2 weight-%, such as calcium laurate, calcium stearate, calcium arachinate and calcium-12-oxyetereate, as well as the corresponding tin, zinc and magnesium salts.

All these additives can be present alone or mixed with each other, for example two or several modifiers which are different from each other, in a total amount of 0.1 to 70.0 weight-%, preferably 2 to 45 weight-%, referring to the total amount of the foil.

Short-fiber-reinforced plastic foils of the invention which are of particular interest for their technical use include approximately 44 to 55 weight-% of plasticized polyvinyl chloride as the plastic matrix, which contains approximately 2 to 16 weight-% of surface treated glass fibers of a length of 3 to 6 mm, and as an additive approximately 35 to 45 weight-% of mainly plasticizers, stabilizers, co-stabilizers, lubricants, fungicides and, if required,

modifiers; also a plastic matrix containing approximately 75 to 80 weight-% of ethylene vinyl acetate grafted with

polyvinyl chloride, approximately 5 to 10 weight-% of surface-treated glass fibers of a length of 3 to 6 mm and

approximately 2 to 20 weight-% of an additive, mainly a stabilizer, co-stabilizer, lubricant, fungicide and, if required, a modifier; as well as a plastic matrix of

approximately 90 to 95 weight-% of ultra-low density

polyethylene containing approximately 2 to 5 weight-% of surface-treated glass fibers of a length of 3 to 6 mm and approximately 2 to 5 weight-% of an additive, mainly a

modifier.

The short-fiber-reinforced plastic foil of the invention is primarily a soft, flexible, economically

advantageous structure having excellent overall properties, of which an excellent dimensional stability, high aging resistance, very good weathering, impermeability to moisture, high load-carrying ability (important with ground water seals, for example), ability to withstand being walked on, resistance to chemical effects, mainly great mechanical stability and thermal stability, great tensile strength, low module of elasticity, permeability to water vapor, low coefficient of elongation, little shrinking, very good resistance to

microorganisms, ability of the foil to be recycled and good mechanical attachment and adhesiveness should be mentioned. Furthermore, this structure is stable over a length of time from low temperatures (-30º) to high temperatures (+80ºC); it primarily has increased tearing resistance along with

simultaneous greater stretching, which results in an

improvement of the total dynamic characteristics of the short-fiber-reinforced plastic foil structure of the invention.

Manufacture of the short-fiber-reinforced plastic foil can be performed in accordance with known processes, such as compressing, casting or calendering, extrusion, blowing, drawing or brushing processes. After manufacture, the short-fiber- reinforced plastic foil is pre-fabricated in the factory primarily into the form of rolls or into tarpaulins.

The preferred process is the calendering process. With this process, for example, the matrix components (for example, S-PVC powder), the surface-treated short fibers and, if required, the additives are first intimately mixed in accordance with the dry blend method in a hot mixing device while stirring at a temperature of approximately 110ºC to 130ºC for approximately 8 to 12 minutes and the dry blend is prepared. However, the surface-treated short fibers can also be directly placed into the compounder or planetary roller extruder in which the dry blend (for example S-PVC powder and the additives, if required) are already present. After cooling the mixture to about 65ºC to 75ºC in the cooling mixer, the mixture is placed into a multi-axial compounder or a multi-axial planetary roller extruder in which

plastification of the mixture takes place at approximately 150ºC to 180ºC. Subsequently the plastified mixture is conveyed from the extruder to the calender and is passed between the calender rollers at suitable roller pressures, temperature and speed, in the course of which it is provided with defined thickness, density, transparency or defined surface effects, such as luster, smoothness and designs. The finished foil is subsequently rolled up. In this connection it is essential that all components are homogeneously and intimately admixed before entry into the calender. Use of this process does not result in overstretching problems which can occur particularly with non-reinforced foils.

Short-fiber-reinforced plastic foils are employed for the most different uses, such as floor and wall coverings, for pipes, hoses, ribbons and profiled sections and

particularly as foils themselves, i.e. as thin, flat, webs which can be rolled up and have a thickness of approximately 0.1 to 6.0 mm, mainly 0.8 to 4 mm, for flexible seals and insulations (heat, cold, sound), for example in roof

construction, tunnel construction, for pool systems, for pond systems, for landfill systems, as linings for chemical vats and in water protection, for example as catch basins, drinking water reservoirs and tank linings.

The advantages of the short-fiber-reinforced plastic foil in accordance with the invention are obvious.

The capacity of being welded by robots is considerably improved over that of non-reinforced foils and the thermal expansion coefficient is lowered. The dimensional stability is also increased. Reductions in tensile strength are caused by contractions when welding non-reinforced foils and in contrast thereto the stability of the seams is retained when using short-fiber-reinforced plastic foils.

In contrast to foils reinforced by lattices, woven fabrics, webs, weaves or fleeces, all knot covering problems are removed. The adhesion of the fabric to the foil plays a decisive part with fabric-reinforced foils, because poorly adhering fabrics lead to delamination. Such delamination problems are completely secondary with short-fiber-reinforeed plastic foils of the invention, because the short fibers are anisotropically distributed in the matrix.

The handling properties and mainly the adhesion of the short fibers are considerably improved over conventional short- fiber-reinforced plastic materials in accordance with the initially cited prior art. In contrast to the surface-treated cotton fibers in plasticized PVC, the plastic foils of the invention have universal applicability for the most diverse surface-treated short fibers.

Manufacture of the short-fiber-reinforced plastic foils is considerably simpler with the calender process.

Added to this is that the short-fiber-reinforced plastic foils are easier to recycle than a fabric-reinforced or fleece-reinforced foil. Finally, short-fiber-reinforced plastic foils have a lesser volume than lattice-reinforced foils.

The following examples illustrate the invention, without its being limited thereby.

Example 1 (Manufacturing the short-fiber-reinforced foil)

The dry blend is prepared in a hot mixing device (interior temperature 120ºC) in accordance with the dry blend process (Kunststoff Handbuch PVC [PVC Plastic Handbook], part 2, Becker/Braun, 1986, published by Hanser-Verlag, pp. 832 to 834) from the components recited in Table 1 in the percentage amounts stated by stirring them in approximately 8 to 12 minutes. Next, the short fibers surface-treated with an amino silane compound or an epoxy silane compound are introduced into the hot mixing device with the amounts/lengths also recited in Table I under further stirring and mixing for approximately 2 to 4 minutes at 120°C. Following cooling of the mixture in a cooling mixer to approximately 70ºC, the mixture is placed into a Buss kneader, in which homogenization and plastification of the mixture takes place at approximately 160ºC. Subsequently the plastified mixture is conveyed from the extruder to the calender, in which the fiber-reinforced foil is made with a desired thickness of 0.8 to 4 mm and a width of l to 2 meters. Next, it is cooled to 25ºC by cooling rollers and is rolled up.

The properties of the short-fiber-reinforced foils obtained in accordance with Examples 1 to 12 can be found in Table II below.

The properties of the short-fiber-reinforced foils obtained in accordance with Examples 13 to 20 can be found in Table III below.

The tests for "Dimensional Stability 1" and

"Dimensional Stability 2" in Table II were performed as follows:

Dimensional Stability 1

This test is performed following the standard SIA 280.

Round test bodies are stamped out for this purpose, their dimensions are measured and they are stored at 80ºC for 24 hours.

After the samples have cooled, they are again measured and the change in diameter is recorded.

Dimensional Stability 2

This test is performed as follows:

Rectangular test bodies are heated to 80°C, isolated and immediately stretched with a force of 200 N. The stretched samples are immediately cooled in ice water and measured. Subsequently the samples are again stored at 80°C for 24 hours and the change in length measured.

Example 21

A foil of a thickness of 1.5 mm and a width of 200 cm, produced in accordance with Example 2 with the addition, of 10% of EC glass fibers of 3 mm in length, is rolled out over the thermal insulation and is mechanically fastened at the corners and the edge area in accordance with the prescribed placement instructions. The foil webs are welded together along their long sides by means of hot air.

Among other things, the foil placed in this manner has the following properties: high UV and weathering

resistance, good mechanical values (tensile strength,

resistance to tear propagation, etc.), very good resistance to environmental effects (microorganisms, water, wind, etc.), permeability to water vapor, good chemical resistance, very good dimensional stability, capability for recycling and good flexibility when cold.

Example 22

A foil produced in accordance with Example 3 with an addition of 5% EC-10 glass 4.5 mm, a width of 200 cm and a thickness of 2.4 mm is fastened to the wall of a tunnel with mechanical fastening pins. The long sides of the foils are welded together by means of hot air. In this way the tunnel lining foil protects against the intrusion of water.

The foil placed in this manner has the following properties, among others: good mechanical strength, good dimensional stability, good resistance to the intrusion of water, it is flame-retardant and capable of being recycled.

Claims

WHAT IS CLAIMED IS :

1. A short-fiber-reinforced plastic foil, characterized in that it is flexible and consists of a plastic matrix containing surface-treated short fibers.

2. A shortr-fiber-reinforσed plastic foil in accordance with claim 1, characterized in that the matrix is a

thermoplastic material, an elastomer, a thermoplastic

elastomer or a polymer blend.

3. A short-fiber-reinforced plastic foil in accordance with claim 2, characterized in that the matrix is a

thermoplastic material.

4. A short-fiber-reinforced plastic foil in accordance with claim 3, characterized in that the matrix is a

homopolymer made of polyethylene, polypropylene, polyamide, polyester or polyvinyl chloride, or a copolymer made of styrene/acrylonitrile, styrene/butadiene/acrylonitrile or polyvinyl chloride/ethylvinyl-acetate.

5. A short-fiber-reinforced plastic foil in accordance with claim 4, characterized in that the matrix is a

plasticized polyvinyl chloride, ethylene vinyl acetate grafted with polyvinyl chloride or an ultra-low density polyethylene.

6. A short-fiber-reinforcea plastic foil in accordance with one of the claims l to 5, characterized in that the surface-treated short fibers have a length of 0.3 to 10 mm and a diameter of 5 μm to 1 mm.

7. A short-fiber-reinforced plastic foil in accordance with claim 6, characterized in that the surface-treated short fibers have a length of 1 to 6 mm.

8. A Short-fiber-reinforced plastic foil in accordance with one of the claims 1 to 7, characterized in that the foil contains 1 to 40 weight-% of surface-treated short fibers.

9. A short-fiber-reinforced plastic foil in accordance with claim 8, characterized in that the foil contains 2 to 16 weight-% of surface-treated short fibers.

10. A short-fiber-reinforced plastic foil in accordance with one of the claims 1 to 9, characterized in that the surface-treated fibers are synthetic fibers or textile fibers.

11. A short-fiber-reinforced plastic foil in accordance with claim 10, characterized in that the synthetic fibers are boron fibers, glass-ceramic fibers, glass fibers, carbon fibers, metallic fibers or rock fibers.

12. A short-fiber-reinforced plastic foil in accordance with claim 10, characterized in that textile fibers are aramide fibers, polyvinyl chloride fibers, polypropylene fibers, polyphenylene sulfide fibers, polyetherimide fibers, polyamide fibers, polyimide fibers or polyester fibers.

13. A short-fiber-reinforσed plastic foil in accordance with claim 11, characterized in that the short fibers are glass fibers.

14. A short-fiber-reinforced plastic foil in accordance with one of the claims 1 to 13, characterized in that the short fibers are surface-treated with epoxy silane or amino silane.

15. A short-fiber-reinforced plastic foil in accordance with one of the claims 1 to 14, characterized in that the foil additionally contains one or more additives in an amount of 0.1 to 70 weight-%.

16. A short-fiber-reinforced plastic foil in accordance with one of the claims 1 to 15, characterized in that the plastic matrix contains approximately 44 to 55 weight-% of plasticized polyvinyl chloride which contains approximately 2 to 16 weight-% of surface-treated glass fibers of a length of 3 to 6 mm and approximately 35 to 45 weight-% of at least one additive selected from the group consisting of plasticizers, stabilizers, co-stabilizers, lubricants, fungicides, and modifiers.

17. A short-fiber-reinforced plastic foil in accordance with one of the claims 1 to 15, characterized in that the plastic matrix contains approximately 75 to 80 weight-% of ethylene vinyl acetate grafted with polyvinyl chloride, which contains approximately 2 to 10 weight-% of surface-treated glass fibers of a length of 3 to 6 mm and approximately 10 to 20 weight-% of an additive selected from the group consisting of plasticizers, stabilizers, co-stabilizers, lubricants, fungicides, and modifiers.

18. A short-fiber-reinforced plastic foil in accordance with one of the claims 1 to 15, characterized in that the plastic matrix contains approximately 90 to 95 weight-% of ultra-low density polyethylene, which contains approximately 2 to 5 weight-% of surface-treated glass fibers of a length of 3 to 6 mm and approximately 2 to 5 weight-% of a modifier.

19. A method for producing a short-fiber-reinforced plastic foil in accordance with one of the claims 1 to 18 by means of a calender method.

20. A method of use comprising using the short-fiber-reinforced plastic foil in accordance with one of the claims 1 to 18, for constructing a roof or tunnel.

21. A method of use comprising using the short-fiber-reinforced plastic foil in accordance with one of the claims to 18, as a seal for landfills, water reservoirs, tank linings and water protection.