FR2778579A1 - Multilayer mat protecting ground against hydrocarbons and industrial solvents - Google Patents

Abstract

The laminated structure comprises a top non-woven hydrophobic material (2), a hydrophobic layer (3) of thermoplastic fibers forming an absorbent bed for common hydrocarbons and industrial solvents, a thermoplastic sealing film (4) and a lower covering (5). Preferred Features: A low-melting, strongly-adherent binder joins non-woven material to the absorbent bed. The sealing film (4) is self-adhesive on both faces, assuring bonding of the lower non-woven covering to the absorbent bed, which is hydrophobic and oleophilic. The weight of the upper non-woven is 20-100 g/m<2>, preferably 40-60 g/m<2>. The weight of the lower, preferably hydrophobic non-woven is 40-200 g/m<2>, preferably 60-100 g/m<2>. These sheets are formed by regular continuous filaments, preferably bonded by hot calendering. The non-woven bed is a monolayer of weight 350-1500 g/m<2>, preferably 600-1200 g/m<2>. It comprises discontinuous melt-blown fibers. The sealing film, in materials similar to the binder, is 25-80 mu m thick, preferably 40-60 mu m thick. The top layer is suitable for decorative or informative printing before or after assembly. The mat assembly includes means of holding-down, e.g. eyelets or loops. The mat may laid protectively on railway ballast.

Description

- 1 -

DESCRIPTION

The present invention relates in particular to the field of environmental protection, safety and prevention, more particularly in connection with interventions on various means of transport resulting in spills or projections of hydrocarbons or solvents, and a for object a multilayer protective sheet, as well as a mat and a device

protection formed from such a web.

Currently, hydrocarbons and solvents which are deliberately or involuntarily spilled on the ground, following interventions or due to the presence of leaks, in repair shops, tracks or parking lots, places of temporary stoppage (portions of railways) or the like, remain on the surface, drain through wastewater canals or

seep into the superficial and even deep layers of the soil.

In all cases, this results in aesthetic and chemical pollution of the area concerned, as well as possibly risks for personnel.

moving at this area.

Various products are already known, in particular in the form of a non-woven mattress, making it possible to collect by absorption the hydrocarbons and spilled solvents. However, these known products generally do not have a sufficiently strong structure to withstand significant mechanical stresses and to allow their handling after their impregnation, do not guarantee total protection of the floors against these liquid pollution (the liquids pass through the absorbent layer), appear soiled after absorption of liquids and unravel upon physical contact or exposure

to air flows.

The object of the present invention is in particular to alleviate the

aforementioned disadvantages.

To this end, its object is a multilayer protective sheet, in particular for protecting floors against pollution by hydrocarbons or industrial solvents, characterized in that it has a layered structure formed by the association of a non-woven web. upper hydrophobic woven fabric, a hydrophobic layer of thermoplastic fibers forming an absorbent pad for the usual hydrocarbons and industrial solvents, a waterproof film

thermoplastic and a lower veil.

-2-

The invention will be better understood, thanks to the following description, which

relates to a preferred embodiment, given by way of non-limiting example, and explained with reference to the appended schematic drawings, in which: FIG. 1 is a schematic sectional view of a multilayer web according to the invention, the Figure 2 is a top view of a protective mat installed between two railroad tracks, and, Figure 3 is a side elevational view in section showing the attachment of the protective mat shown in Figure 2 to l 'one of its ends

longitudinal.

As shown more particularly in Figure 1 of the accompanying drawings, the multilayer web has a layered structure formed by the association, successively, between its upper and lower faces, of an upper hydrophobic nonwoven web 2, of a hydrophobic layer 3. of thermoplastic fibers forming an absorbent mat for hydrocarbons and solvents

usual industrial, a thermoplastic waterproof film 4 and a bottom veil 5.

The unitary sandwich structure of the multilayer web is ensured, on the one hand, by the fact that the upper nonwoven web 2 is secured to the intermediate absorbent mat 3 by means of a binder 6 with low melting temperature and high tackiness. and, on the other hand, by the fact that the waterproof film 4 is self-adhesive on both sides and ensures the assembly of the lower nonwoven web 5 with the

hydrophobic and oleophilic absorbent mattress 3.

Thanks to the invention, a product is thus obtained with a great power of absorption of hydrocarbons and solvents (intermediate absorbent mat), constituting a completely waterproof protection for the covered areas (waterproof film) and having a great mechanical resistance and surfaces. to structure

consolidated and lint-free (upper and lower non-woven sails).

According to a first characteristic of the invention, the basis weight of the upper nonwoven web 2 is between 20 and 100 g / m2, preferably between 40 and 60 g / m2, and the basis weight of the lower web 5, of nonwoven type and preferably hydrophobic, is between 40 and 200 g / m2, preferably between 60 and 100 g / m2. these webs being formed of continuous and regular filaments (with a diameter of about 20 μm) of polypropylene preferentially bonded by hot calendering (thus increasing the resistance

mechanical and planning the surface condition of said sails).

Advantageously, the nonwoven absorbent mattress 3 is of the

single-layer, has a weight of between 350 and 1500 g / m2.

-3- preferably between 600 and 1200 g / m2, and consists of discontinuous solid microfibers (1 to 10 μm in diameter and 1 to 5 cm in length) based on

polypropylene and / or polyethylene, obtained by fusion blowing.

The thick layer of fibers forming the absorbent mat 3 may, for example, consist of a non-woven product marketed by the applicant under the name MICROSORB (registered name) and be obtained by the process and with the process described in the patents of the States. - United of America Nos. 3,704,198, 3,849,241, 4,889,476 and 4,986,743 in the name of EXXON CHEMICAL COMPANY by extruding a polypropylene-type polymer having a viscosity (at given temperature and extrusion speed) such as: MFI 400-1200 g - 10

minutes according to ISO 1133.

However, it is also possible to use a mixture of polymers such as

that, for example, polypropylene: 100-90% and polyethylene: 0-10% by weight.

The retention of polluting liquids by the absorbent mattress is carried out

about 90% by capillarity and about 10% by chemical binding.

In accordance with another characteristic of the invention, the binder at low melting point 6 is chosen from the group formed by polyurethane glues, polyester glues, polyethylene glues and poly (ethylene / vinyl acetate) or EVA glues, has a softening temperature of less than 90 C, preferably less than 80 C, and is applied at a weight dose of between 5 and 30 g / m2, preferably between 10 and 20 g / m2

(advantageously around 15g / m2).

In addition, the waterproof film 4, resistant in particular to hydrocarbons and industrial solvents, consists of a thermoplastic material chosen from the group formed by polyethylene, polyurethane and poly (ethylene / vinyl acetate) (EVA) and has a thickness between 25 and 80 pm,

preferably between 40 and 60 μm (advantageously around 50 Prn).

Furthermore, the web 1 can also be used for advertising purposes or for informing the public and consumers, the upper nonwoven web 2 then being suitable for receiving a decorative and / or informative printing on its visible external face, front or rear. after its assembly with the

other layers 3 to 5 of the tablecloth 1.

Said upper web 2 will have a structure permeable to liquids which will thus be fully transmitted to the absorbent mattress 3, the latter only retaining the hydrocarbons and solvents concerned, without their presence being too visible (the upper web forming a cover covering the mattress 3 throat

liquids).

-4- In order to further reduce the possible traces of soiling at the level of the upper web 2, the latter could possibly be treated to make it simultaneously hydrophobic and permeable to hydrocarbons and their

derivatives (solvents).

Thus, all of the liquids arriving on the multilayer web passes through the upper web 2, the hydrocarbons and the solvents concerned being fixed by the mattress 3 and the water flowing through the edges of said web 1. The waterproof film 4 guarantees that no liquid seeps into the soil area below the

multilayer tablecloth 1.

A subject of the present invention is also a mat for protecting a surface against the effusions and projections of solvents and hydrocarbons, characterized in that it is mainly constituted by a portion of multilayer sheet 1 as described above. , and provided on at least two opposite edges 7, 7 'with means 8 for fixing or anchoring regularly spaced and integral with the different layers 2 to 5 of the web 1, for example in the form of eyelets, carabiners, loops elastic or the like. In accordance with a preferred embodiment of the invention, said protective mat consists of an elongated strip of multilayer ply 1 provided at its longitudinal side edges 7, 7 'with fixing and anchoring means 8, the sails not -woven upper 2 and lower 5 stopping laterally substantially at the level of the edges of the intermediate layer 3

forming an absorbent mattress.

Finally, the invention also relates, in particular, to a device for protecting the ballast or rubble arranged between the rails of a railway track or between two railway tracks, characterized in that it consists of at least one belt 1 elongated from the type described above, attached laterally to the fastening elements 9 "of the rails 9 on the sleepers 9 'and at its longitudinal ends opposite at least to each of the last covered sleepers 9', the width of said belt being less than the spacing between rails, so as to avoid the establishment of bridges

electrical between them.

As shown in Figure 2 of the accompanying drawings, the mat 1 can be provided with eyelets 8 through which can pass a fixing cord which also clings to the pads, lag bolts, griffins or the like which ensures the maintenance

rails 9.

To prevent their lifting and their tearing due to the turbulence and depressions generated by the passage of high-speed trains, -5- each belt 1 can be kept on the ground, at each of its two longitudinal ends, on the one hand . by burying an end portion 1 'of said mat I under a layer of ballast or rubble 10 and, on the other hand, by maintaining said mat 1 against the last cross member 9' covered by the latter, for example by the 'intermediary of at least one profiled bracket 11 with L-section attached to said mat 1 and fixed to said cross member 9' by nails 12 or the like (figures

2 and 3).

Of course, the invention is not limited to the embodiment

described and shown in the accompanying drawings. Modifications are still possible.

in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without going beyond the scope of

protection of the invention.

-6-

Claims (11)

1. Multilayer protective sheet, in particular for protecting floors against pollution by hydrocarbons or industrial solvents, characterized in that it has a layered structure formed by the association of a non-woven upper hydrophobic web (2), a hydrophobic layer (3) of thermoplastic fibers forming an absorbent mat for hydrocarbons and usual industrial solvents, a waterproof film (4) thermoplastic and a lower veil (5). 2. Multilayer web according to claim 1, characterized in that the upper nonwoven web (2) is secured to the intermediate absorbent mat (3) by means of a binder (6) at low melting point and high tackiness and in that the waterproof film (4) is self-adhesive on both sides and assembles the lower non-woven web (5) with the absorbent mat (3) hydrophobic and oleophilic. 3. Multilayer web according to any one of claims 1 and 2, characterized in that the basis weight of the upper nonwoven web (2) is between 20 and 100 g / m2, preferably between 40 and 60 g / m2, and in that the basis weight of the lower nonwoven web (5) , of nonwoven type and preferably hydrophobic, is between 40 and 200 g / m2, preferably between 60 and g / m2, these webs being formed of continuous and regular filaments of polypropylene preferably bonded by hot calendering. 4. Multilayer web according to any one of claims 1 to 3, characterized in that the non-woven absorbent mattress (3) is of the single-layer type, has a basis weight of between 350 and 1500 g / m2, preferably between 600 and 1200 g / m2, and consists of solid discontinuous microfibers, with polypropylene and / or polyethylene base obtained by fusion blowing. 5. Multilayer web according to any one of claims 2 to 4, characterized in that the binder at low melting point (6) is chosen from the group formed by polyurethane glues, polyester glues, polyethylene glues and poly (ethylene / vinyl acetate) glues, has a temperature of softening less than 90 C, preferably less than C, and is applied at a weight dose of between 5 and 30 g / m2, preferably between 10 and 20 g / m2. -7 - 6. Multilayer web according to any one of claims 2 to 4, characterized in that the waterproof film (4), resistant in particular to hydrocarbons and industrial solvents, consists of a thermoplastic material chosen from the group formed by polyethylene, polyurethane and poly (ethylene / vinyl acetate) and has a thickness between 25 and pim, preferably between 40 and 60 gum. 7. Multilayer web according to any one of claims 1 to 6, characterized in that the upper nonwoven web (2) is adapted to receive a decorative and / or informative printing on its visible external face, front or after its assembly with the other layers (3 to 5) of the web (1). 8. Protective mat for a surface against effusions and projections of solvents and hydrocarbons, characterized in that it is mainly constituted by a portion of multilayer sheet (1) according to one. any one of claims 1 to 7 provided on at least two opposite edges (7, 7 ') of means (8) for fixing or anchoring regularly spaced and integral different layers (2 to 5) of the web (1), for example in the form of eyelets. snap hooks, elastic loops or the like. 9. Protective mat according to claim 8, characterized in that it consists of an elongated strip of multilayer ply (1) provided at its longitudinal side edges (7, 7 ') with fixing and anchoring means ( 8), the upper (2) and lower (5) nonwoven webs stopping laterally substantially at the edges of the intermediate layer (3) forming an absorbent mat. 10. Device for protecting the ballast or rubble between the rails of a railway track or between two railway tracks, characterized in that it consists of: at least one elongated carpet (1) according to any one of claims 8 and 9 laterally secured to the fixing elements (9 ") of the rails (9) on the sleepers (9 ') and at its longitudinal ends opposite at least to each of the last covered sleepers (9'), the width of said belt being less than the spacing between rails. 11. Protective device according to claim 10, characterized in that each mat (1) is held on the ground, at each of its two longitudinal ends, on the one hand, by burying an end portion (1). ') of said mat (1) under a layer of ballast or rubble (10) and, on the other hand, by maintaining said mat (1) against the last cross member (9') covered by the latter, for example by the intermediate of at least one bracket (11) profiled in L-section attached to said mat (1) and fixed to said cross member (9 ') by nails (12) or the like.