SELF-ADHESIVE FILM FOR SOIL FUMIGATION

Abstract

The present invention relates to the use of a fumigant barrier film for treating soil by fumigation, said film having, on at least one portion of the outer surface thereof or on at least one portion of the inner surface thereof or on at least one portion of the outer and inner surfaces thereof, at least one continuous self-adhesive or self-sticking or tackifying area. The present invention also relates to the method for sealing soil intended for fumigation treatment or in the process of fumigation treatment or which has been treated by fumigation, by covering said soil with a self-adhesive fumigant barrier film, as well as to a kit for fumigation treatment including at least one self-adhesive fumigant barrier film and at least one fumigant.

Claims

1. A method for fumigation treatment of soils, comprising using a self-adhesive barrier film having fumigant barrier properties and having an outer surface and an inner surface, wherein at least a portion of at least one of the outer surface or the inner surface comprises at least one of a continuous self-adhesive area, a continuous self-sticking area or a continuous tackifying area.

2. The method according to claim 1, wherein the at least one of the continuous self-adhesive area of the film, continuous self-sticking area or the continuous tackifying area of the film comprises i a continuous area parallel to the largest length of the film.

3. The method according to claim 1, wherein the film comprises at least one layer, said layer comprising a polymer selected from the group consisting of polyolefins, polyamides and polyesters; and wherein the film further comprises at least one of a tackifying agent or a tackifying resin.

4. The method according to claim 1 wherein the thickness of the self-adhesive fumigant barrier film is between 5 μm and about 100 μm.

5. The method according to claim 1 wherein the soils treated by fumigation comprise at least one of soils or substrates intended for market-gardening, horticultural crops, arboriculture, or grapevines.

6. A method for sealing a soil for fumigation treatment, said method comprising covering at least a portion of said soil with a self-adhesive barrier film wherein the film has fumigant barrier properties, an outer surface and an inner surface wherein at least a portion of the at least of one of the outer surface and the inner surface comprises at least one continuous self-adhesive area.

7. The method according to claim 6, wherein covering the soil by the self-adhesive fumigant barrier film comprises at least one of the following techniques: a) placing a first width of the self-adhesive fumigant barrier film on the soil, overlapping an area of the first width of the self-adhesive fumigant barrier film with a second width of said self-adhesive fumigant barrier film, and optionally applying pressure on the overlapping area, simultaneously or after placement of the second width of self-adhesive fumigant barrier film; b) placing a first width of not self-adhesive fumigant barrier film on the soil and placing a second width of not self-adhesive fumigant barrier film a distance from and parallel to the first layer of not self-adhesive fumigant barrier film and then placing a small strip of the self-adhesive fumigant barrier film between the first and second widths of the not self-adhesive, fumigant barrier film, whereby the small strip of self adhesive film overlaps the first and second widths of the not self-adhesive fumigant barrier film, and optionally applying pressure on the small strip of self-adhesive fumigant barrier film, simultaneously or after placement of the small strip of self-adhesive fumigant barrier film; c) placing alternating widths of the self-adhesive fumigant barrier film and not self-adhesive fumigant barrier film on the soil, whereby the self-adhesive film overlaps an area of the not self-adhesive fumigant barrier film, and optionally applying pressure on the overlapping area, simultaneously or after placement of the widths of fumigant barrier film.

8. The method according to claim 6 further comprising a step of injecting at least one fumigant either immediately before covering the soil with the fumigant barrier film, or immediately after covering the soil with the fumigant barrier film.

9. The method according to claim 6, wherein the fumigant is selected from the group consisting of methyl bromide, methyl iodide, methyl isothiocyanate, allyl isothiocyanate, 1,3-dichloropropene, chloropicrin, ethanedinitrile, sulfuryl fluoride, phosphine, tetrathiocarbonate, metam-sodium, metam-potassium, tetrahydro-3,5-dimethyl-1,3,5-thiadiazine-2-thione, alkyl sulfides, dialkyl disulfides, dialkyl polysulfides, thiosulfinates and combinations thereof.

10. A kit for fumigation treatment of a soil wherein the kit comprises at least one self-adhesive fumigant barrier film and at least one fumigant.

11. The method according to claim 7 further comprising a step of injecting at least one fumigant either immediately before covering the soil with the fumigant barrier film, or immediately after covering the soil with the fumigant barrier film.

12. The method according to claim 7, wherein the fumigant is selected from the group consisting of methyl bromide, methyl iodide, methyl isothiocyanate, allyl isothiocyanate, 1,3-dichloropropene, chloropicrin, ethanedinitrile, sulfuryl fluoride, phosphine, tetrathiocarbonate, metam-sodium, metam-potassium, tetrahydro-3,5-dimethyl-1,3,5-thiadiazine-2-thione, alkyl sulfides, dialkyl disulfides, dialkyl polysulfides, thiosulfinates and combinations thereof.

13. The method according to claim 8, wherein the at least one fumigant is selected from the group consisting of methyl bromide, methyl iodide, methyl isothiocyanate, allyl isothiocyanate, 1,3-dichloropropene, chloropicrin, ethanedinitrile, sulfuryl fluoride, phosphine, tetrathiocarbonate, metam-sodium, metam-potassium, tetrahydro-3,5-dimethyl-1,3,5-thiadiazine-2-thione, alkyl sulfides, dialkyl disulfides, dialkyl polysulfides, thiosulfinates and combinations thereof.

14. The method according to claim 6, wherein the film comprises at least one layer, said layer comprising a polymer selected from the group consisting of polyolefins, polyamides and polyesters; and wherein the film further comprises at least one of a tackifying agent or a tackifying resin.

15. The method according to claim 6, wherein the thickness of the self-adhesive barrier film is between 5 μm and 100 μm.

16. The method according to claim 6, wherein the soils treated by fumigation comprise at least one of soils or substrates intended for market-gardening, horticultural crops, arboriculture, or grapevines.

17. The kit for fumigation treatment of a soil according to claim 10, wherein the at least one fumigant comprises at least one volatile sulfur-containing organic compound.

18. The kit for fumigation treatment of a soil according to claim 10, wherein the at least one fumigant comprises dimethyl disulfide.

Description

[0102] The following examples illustrate the invention but without limiting its scope, which is defined by the appended claims.

Manufacture of the PE or Barrier, Stretch and Adhesive Film

[0103] Among the known plastic films and in particular those used in the fields of food packaging, protection of elements stored on pallets or for ensilage for example, the films are often so-called “stretch films” that have tackifying properties. More particularly, an extremely stretchable and self-adhesive (tackifying, sticky) film may then be used up to 180% of its initial length. So that the film is optimized for stretch and adhesion, it may for example consist of two or more polymer layers, at least one of which may contain an elastomer, and at least one, identical or different, may contain a tackifier, such as PIB.

[0104] Other examples of fumigation films having tackifying properties are presented below:

Film No. 1a: conventional gas barrier film prepared by extrusion blow molding, and containing three layers as follows:

TABLE-US-00001 Polyethylene EVOH Polyethylene
Film No. 1b: conventional gas barrier film prepared by extrusion blow molding, with one tackifying layer:

TABLE-US-00002 Polyethylene EVOH Polyethylene + PIB
Film No. 1c: conventional gas barrier film prepared by extrusion blow molding, containing four layers, including one tackifying layer:

TABLE-US-00003 Polyethylene EVOH Polyethylene Polyethylene + PIB
Film No. 2a: transparent photocatalytic gas barrier film prepared by extrusion blow molding, containing three layers as follows:

TABLE-US-00004 Polyethylene EVOH Polyethylene + photocatalytic TiO.sub.2
Film No. 2b: gas barrier film, photocatalytic and transparent, with tackifying layer, prepared by extrusion blow molding, and containing four layers as follows:

TABLE-US-00005 Polyethylene EVOH Polyethylene + photocatalytic TiO.sub.2 Polyethylene + PIB
Film No. 3a: colored photocatalytic gas barrier film, prepared by extrusion blow molding, and containing four layers as follows:

TABLE-US-00006 Polyethylene EVOH Polyethylene + photocatalytic TiO.sub.2 Polyethylene + carbon black
Film No. 3b: colored photocatalytic gas barrier film, with tackifying layer, prepared by extrusion blow molding, and containing four layers as follows:

TABLE-US-00007 Polyethylene EVOH Polyethylene + photocatalytic TiO.sub.2 Polyethylene + carbon black + PIB
Film No. 3c: colored photocatalytic gas barrier film, with tackifying layer, prepared by extrusion blow molding, and containing five layers as follows:

TABLE-US-00008 Polyethylene EVOH Polyethylene + photocatalytic TiO.sub.2 Polyethylene + carbon black Polyethylene + PIB

Example of Application of a “Self-Adhesive” Gas Barrier Film

[0105] For this test, tackifying (or self-adhesive) films, corresponding to film No. 1b above, with three layers with a total thickness of 30 μm, width of 2.5 m and length of 100 m, are used. Two series of films are obtained by the extrusion blow molding technique, familiar to a person skilled in the art, using:

for the first series: a tackifying polyethylene masterbatch (PE)/PIB type PW 60, marketed by the company Polytechs, at a rate of 5%, 10% and 15% (i.e. 3 films) by weight of tackifying masterbatch relative to the total weight of the film, and
for the second series: a tackifying polyethylene masterbatch (PE)/PIB type PW 70, marketed by the company Polytechs, at a rate of 5%, 10% and 15% (i.e. 3 films) by weight of tackifying masterbatch relative to the total weight of the film.

[0106] Many techniques may be envisaged for stretching a film and covering soil that is intended to be fumigated with a film that is impervious to the fumigant vapors. Among these techniques, we may mention, for purposes of illustration, the following three techniques:

Technique No. 1

[0107] Placement of the film is performed conventionally with a “filming” machine, for example a machine commonly used for fumigation treatment with methyl bromide, using a solvent adhesive or translucent hot-melt adhesive. The operation comprises placement of a first strip (or width) of self-adhesive fumigant barrier film, then gluing of a second width of film on a portion of this first strip of film, with an overlap width from about 10 cm to 30 cm.

Technique No. 2

[0108] Using an existing filming machine, of the type described for example in application WO 2001/0119167, a first strip of gas barrier film (conventional, non-tackifying) and a second strip are placed, leaving a space about 5 cm to 20 cm wide between these two widths. Then, while placing the third strip, bonding the strip of self-adhesive gas barrier film (about 10 cm to 50 cm wide, typically 40 cm) between the 2 strips placed previously, by simple pressure.

Technique No. 3

[0109] Using the filming machine from Technique 1 and/or from Technique 2, alternating placement of widths of non-adhesive (non-tackifying) barrier film and of self-adhesive (tackifying) barrier film, the widths generally being roughly 3 meters wide.

Example of Application of a Film According to Technique No. 1

[0110] Application of the various films was carried out according to technique No. 1, namely with the filming machine used for fumigation treatment with methyl bromide.

[0111] A first strip of self-adhesive barrier film (film 1b)) is placed, and then a second strip of self-adhesive barrier film (film 1b)) is bonded to the edge of this first strip of film, by simple pressure, and so on, so as to cover the whole width of the field. The overlap area is about 20 cm.

[0112] All the tackifying fumigant barrier films that have been described in the present invention have satisfactory tackifying power for use in soil fumigation, while ensuring perfect imperviousness and thus retaining the fumigant vapors under the film, more precisely between the soil and the film, so that no fumigant vapor, or only very small amounts of fumigant, escape into the atmosphere.

[0113] The use, according to the present invention, of a self-adhesive fumigation film thus offers numerous advantages, among which we may mention:

possibility of sticking/unsticking, of the “Post-it™” type, therefore easy to remove and reposition. This also facilitates removal of the plastic cover,
possibility of using the same recycling channels as for conventional fumigation film,
ease of use of the film without any handling of adhesive during fumigation: the adhesive (or tackifying) agent is added to the film during manufacture, therefore there is no need to add an adhesive (hot-melt adhesive or solvent adhesive) on the strips of films already positioned on the field,
keeping an identical number of operators as observed during placement of conventional fumigation films,
final cost (material and time) lower compared to the gluing techniques for the strips of conventional films.