WO2008026229A1 - Polymer film for use as a cover in agriculture - Google Patents

Polymer film for use as a cover in agriculture Download PDF

Info

Publication number
WO2008026229A1
WO2008026229A1 PCT/IT2006/000631 IT2006000631W WO2008026229A1 WO 2008026229 A1 WO2008026229 A1 WO 2008026229A1 IT 2006000631 W IT2006000631 W IT 2006000631W WO 2008026229 A1 WO2008026229 A1 WO 2008026229A1
Authority
WO
WIPO (PCT)
Prior art keywords
film
thermoplastic polyurethane
weight
present
hindered amines
Prior art date
Application number
PCT/IT2006/000631
Other languages
French (fr)
Inventor
Maurizio Zanon
Livio Stefani
Original Assignee
Pati S.P.A.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pati S.P.A. filed Critical Pati S.P.A.
Priority to PCT/IT2006/000631 priority Critical patent/WO2008026229A1/en
Publication of WO2008026229A1 publication Critical patent/WO2008026229A1/en
Priority to SM200900019T priority patent/SMP200900019B/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/08—Copolymers of ethene
    • C08L23/0846—Copolymers of ethene with unsaturated hydrocarbons containing other atoms than carbon or hydrogen atoms
    • C08L23/0869—Acids or derivatives thereof
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
    • A01G13/00—Protecting plants
    • A01G13/02—Protective coverings for plants; Coverings for the ground; Devices for laying-out or removing coverings
    • A01G13/0256—Ground coverings
    • A01G13/0268—Mats or sheets, e.g. nets or fabrics
    • A01G13/0275—Films
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
    • A01G9/00—Cultivation in receptacles, forcing-frames or greenhouses; Edging for beds, lawn or the like
    • A01G9/14—Greenhouses
    • A01G9/1438—Covering materials therefor; Materials for protective coverings used for soil and plants, e.g. films, canopies, tunnels or cloches
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/34—Heterocyclic compounds having nitrogen in the ring
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/08—Copolymers of ethene
    • C08L23/0846—Copolymers of ethene with unsaturated hydrocarbons containing other atoms than carbon or hydrogen atoms
    • C08L23/0853—Vinylacetate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
    • C08L75/04—Polyurethanes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
    • C08L75/04—Polyurethanes
    • C08L75/06—Polyurethanes from polyesters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2310/00—Agricultural use or equipment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/04—Homopolymers or copolymers of ethene
    • C08J2323/08—Copolymers of ethene
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
    • Y02A40/10—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in agriculture
    • Y02A40/25—Greenhouse technology, e.g. cooling systems therefor

Definitions

  • the present invention relates to a polymer film for use in agriculture as a cover for greenhouses and tunnels in accordance with the features set out in the preamble of the main claim.
  • polymer films as covers for agricultural greenhouses. These films have to meet numerous technical requirements both in terms of optical properties, in order to ensure maximum transparency to visible light and at the same time an effective barrier to far infrared radiation (greenhouse effect), and in terms of mechanical properties, such as, for example, tensile strength, yield point, impact strength and tear propagation strength.
  • optical properties in order to ensure maximum transparency to visible light and at the same time an effective barrier to far infrared radiation (greenhouse effect)
  • mechanical properties such as, for example, tensile strength, yield point, impact strength and tear propagation strength.
  • One of the more important technical characteristics sought in a polymer film for applications in the agricultural sector is that of resistance to the degradation caused by the action of sunlight and thermal oxidation. These latter damage the polymer chains over time, draining the film of both its mechanical characteristics and its optical characteristics.
  • a polymer film used as a cover for greenhouses has an average service life of a few dozen months (by way of reference, the example given by Appendix A of standard EN 13206:2001: a film of Class D in a climate zone with irradiation of from 100 to 130 kLy/year has a life of approximately 24 months), after which it becomes necessary to replace it because the film loses its inherent elasticity, becomes brittle and tends to become opaque.
  • the films used in this specific technical field are obtained from a polyolefin base formed, for example, from low density or linear low density polyethylene, commonly known by the acronyms LDPE and LLDPE, or also from ethylene-vinyl acetate or ethylene-butyl acrylate copolymers, commonly known by the respective acronyms EVA/C and EBA/C.
  • LDPE and LLDPE low density or linear low density polyethylene
  • EVA/C ethylene-vinyl acetate or ethylene-butyl acrylate copolymers
  • EVA/C ethylene-vinyl acetate or ethylene-butyl acrylate copolymers
  • UV absorbers Isuch as benzophenones, benzotriazoles, hydroxybenzophenones, benzoic acid esters, triazines, as well as some acrylates, salts and/or organometal complexes based on nickel or other metals, some oxamides and others still.
  • HALS hindered amine light stabiliser
  • UV-absorbing additives in percentages ranging from 2 to 4 times that of the UV absorber. They act by catalytically blocking the radicals which form owing to the effect of the absorption by the polymer chains of the energy provided by solar radiation, thus slowing down the rate of the photo-oxidation and depolymerisation reactions.
  • All types of HALS are potentially effective but, given their behaviour as Lewis bases, they suffer from interaction with acid substances which may block the functional groups thereof. In particular, in the case of films used as covers for greenhouses and tunnels, contact with numerous chemical products which are based on sulphur and halogens and which are normally used in agriculture may rapidly reduce their efficiency.
  • the object of the present invention is to provide a polymer film which is devised structurally and functionally to ⁇ maintain for a longer period the desired functional, mechanical and spectrophotometric characteristics by a greater resistance to the degradation caused by the action of solar radiation.
  • the film comprises a layer of polyolefin-based polymer material in which a light stabiliser based on hindered amines (HALS), and an effective amount of thermoplastic polyurethane, which is referred to hereinafter as TPU for the sake of brevity, are dispersed.
  • HALS hindered amines
  • TPU thermoplastic polyurethane
  • the film is normally of the single-layer type but may likewise be of the multi-layer type, which is coextruded or coupled, as long as the presence of a polyolefin material, of TPU and HALS, is provided for in at least one of the layers forming the film.
  • the polymer base which forms the film according to the invention is a polyolefin selected from those normally used in this type of application, such as, for example, a low density polyethylene (LDPE) or a linear low density polyethylene (LLDPE).
  • LDPE low density polyethylene
  • LLDPE linear low density polyethylene
  • the film is formed from an ethylene-vinyl acetate copolymer (EVA/C) or from an ethylene-butyl acrylate copolymer (EBA/C).
  • EVA/C ethylene-vinyl acetate copolymer
  • EBA/C ethylene-butyl acrylate copolymer
  • a polymer mixture based on EVA/C or EBA/C with LDPE or LLDPE, in any proportion.
  • the polyolefin base is advantageously mixed with the normal additives used in the sector in order to confer the desired antioxidant, slip, antistatic and antidrip properties and the desired properties of selective photo-absorption in the visible light range and/or the ultraviolet range and/or the infrared range, etc., at the dosages suggested by the suppliers of the additives and at any rate known to the experts in the art.
  • the light stabiliser added to the polyolefin-based mixture comprises HALS, which are preferably oligomeric or polymeric and of the secondary and tertiary type and also methylated or at any rate modified and substituted, and is constituted in a preferred composition variant by those substances only.
  • HALS oligomeric or polymeric and of the secondary and tertiary type and also methylated or at any rate modified and substituted
  • the light stabiliser is constituted by methylated HALS or by sterically hindered aminoxyamines, also known as NOR-HALS, in order to make use of the lower basicity thereof.
  • an effective amount of TPU is also added to the basic polymer mixture.
  • the TPU may be either of the aromatic type or of the aliphatic type, with a polyester or polyether structure.
  • the use of aliphatic, polyester or polyether TPU is preferred because aromatic TPU may give rise, as a result of photo-oxidative reactions, to chromophore groups which tend to confer a brownish yellow colour on the film.
  • Films to which aromatic TPU, which is per se advantageously less expensive, is added, could also be used in particular applications where a possible colouring does not have negative effects.
  • TPUs having a polyester structure are generally less expensive, while TPUs based on polyether generally exhibit greater resistance to hydrolysis.
  • the TPU and the HALS are present in a ratio by weight of from 2:1 to 25: 1.
  • the TPU is added to the polymer mixture in such a manner as to attain a fraction by weight of from 5% to 30%, preferably from 7% to 15%, while, for their part, the HALS are added in such a manner as to attain a fraction by weight of from 0.2% to 2.5%, preferably from 0.8% to 1.6%, with respect to the film.
  • the polyolefin family and the TPUs have physico-chemical characteristics which are relatively diverse with respect to each other, so that, in liquid phase, the two compounds are poorly miscible in each other.
  • the TPU and the polyolefin base are selected in such a manner as to have comparable melting points, differing by less than 40 0 C, and similar apparent viscosities in the range of the speed gradients usual for extrusion processes. Examples
  • the criterion of reduction to 50% of the initial value for elongation at break in tensile stress tests according to EN ISO 527-1 and EN ISO 527-3 was used.
  • Specimen 1 did not reach the 750 hours of exposure, corresponding to the first sampling.
  • Specimen 2 test interrupted at 750 hours of exposure owing to the intense brownish yellow colour exhibited by the specimen.
  • Specimen 3 from 3,000 to 3,500 hours
  • Specimen 5 from 2,500 to 3,000 hours.
  • the films of type 4 were found to be sound even at the end of the third winter of use, but with residual mechanical characteristics which unexpectedly suggest that they might last at least another year, with an increase of from 30 to 50% in resistance to photodegradation with respect to the films of the conventional type used as controls.
  • the present invention therefore achieves the object proposed of providing a polymer film having greater resistance to polymer degradation caused by exposure to sunlight.
  • the invention offers numerous other advantages for use, including the fact that the polymer film so obtained has, compared with a conventional polyolefin-based film, improved characteristics of elasticity and tear resistance and greater IR efficiency (greenhouse effect), evaluated as absorption of radiation in the far infrared range, wavelengths of from 7,000 to 13,000 nm, in accordance with the standard EN 13206:2001.
  • the IR efficiency measured on specimens of type 5 film was 75%, against values higher than 85% for the type 4 film obtained in accordance with the present invention.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Environmental Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Soil Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

A polymer film, particularly for use as a* cover in agriculture, comprises at least one layer of polyolefin-based polymer material in which a light stabiliser based on hindered amines (HALS), and an effective amount of thermoplastic polyurethane are dispersed.

Description

Polymer film for use as a cover in agriculture
DESCRIPTION Technical field The present invention relates to a polymer film for use in agriculture as a cover for greenhouses and tunnels in accordance with the features set out in the preamble of the main claim. Technological background
In the technical sector of reference of the present invention, it is known to use polymer films as covers for agricultural greenhouses. These films have to meet numerous technical requirements both in terms of optical properties, in order to ensure maximum transparency to visible light and at the same time an effective barrier to far infrared radiation (greenhouse effect), and in terms of mechanical properties, such as, for example, tensile strength, yield point, impact strength and tear propagation strength. One of the more important technical characteristics sought in a polymer film for applications in the agricultural sector is that of resistance to the degradation caused by the action of sunlight and thermal oxidation. These latter damage the polymer chains over time, draining the film of both its mechanical characteristics and its optical characteristics. In fact, it is known that a polymer film used as a cover for greenhouses has an average service life of a few dozen months (by way of reference, the example given by Appendix A of standard EN 13206:2001: a film of Class D in a climate zone with irradiation of from 100 to 130 kLy/year has a life of approximately 24 months), after which it becomes necessary to replace it because the film loses its inherent elasticity, becomes brittle and tends to become opaque. Typically, the films used in this specific technical field are obtained from a polyolefin base formed, for example, from low density or linear low density polyethylene, commonly known by the acronyms LDPE and LLDPE, or also from ethylene-vinyl acetate or ethylene-butyl acrylate copolymers, commonly known by the respective acronyms EVA/C and EBA/C. Compounds capable of conferring on the polymer mixture the desired properties in terms of photo-oxidation resistance, surface activity, absorption of infrared radiation and modification of transmitted photosynthetically active radiation (P.A.R.), etc., are therefore advantageously added to those polymers.
As regards resistance to the polymer degradation caused by light (photodegradation), it is known to use light stabilisers which slow down, more or less efficiently, the processes which result in the progressive breakage of the polymer chains, thus prolonging the service life of the film. Many families of compounds suitable for use in polymer mixtures as light stabilisers are available on the market. There may be mentioned, for example, UV absorbers, Isuch as benzophenones, benzotriazoles, hydroxybenzophenones, benzoic acid esters, triazines, as well as some acrylates, salts and/or organometal complexes based on nickel or other metals, some oxamides and others still.
Together with the compounds mentioned above, it is also known to use as stabilisers sterically hindered amines, which are usually referred to in the sector by the acronym HALS (hindered amine light stabiliser) and which are identified thus hereinafter for the sake of brevity. HALS are normally dosed together with UV-absorbing additives in percentages ranging from 2 to 4 times that of the UV absorber. They act by catalytically blocking the radicals which form owing to the effect of the absorption by the polymer chains of the energy provided by solar radiation, thus slowing down the rate of the photo-oxidation and depolymerisation reactions. All types of HALS are potentially effective but, given their behaviour as Lewis bases, they suffer from interaction with acid substances which may block the functional groups thereof. In particular, in the case of films used as covers for greenhouses and tunnels, contact with numerous chemical products which are based on sulphur and halogens and which are normally used in agriculture may rapidly reduce their efficiency.
Despite the presence on the market of all of the families of compounds indicated generically above, there is still a need in the technical sector of reference to prolong the service life of polymer films used as covers in agriculture by increasing their resistance to photodegradation. Description of the invention
The object of the present invention is to provide a polymer film which is devised structurally and functionally to\ maintain for a longer period the desired functional, mechanical and spectrophotometric characteristics by a greater resistance to the degradation caused by the action of solar radiation.
That object is achieved by the present invention by means of a polymer film produced in accordance with the claims which follow.
Preferred embodiment of the invention
In accordance with a first aspect of the present invention, the film comprises a layer of polyolefin-based polymer material in which a light stabiliser based on hindered amines (HALS), and an effective amount of thermoplastic polyurethane, which is referred to hereinafter as TPU for the sake of brevity, are dispersed.
The film is normally of the single-layer type but may likewise be of the multi-layer type, which is coextruded or coupled, as long as the presence of a polyolefin material, of TPU and HALS, is provided for in at least one of the layers forming the film.
The polymer base which forms the film according to the invention is a polyolefin selected from those normally used in this type of application, such as, for example, a low density polyethylene (LDPE) or a linear low density polyethylene (LLDPE). Preferably, however, the film is formed from an ethylene-vinyl acetate copolymer (EVA/C) or from an ethylene-butyl acrylate copolymer (EBA/C). Likewise preferred is the use of a polymer mixture based on EVA/C or EBA/C with LDPE or LLDPE, in any proportion. The polyolefin base is advantageously mixed with the normal additives used in the sector in order to confer the desired antioxidant, slip, antistatic and antidrip properties and the desired properties of selective photo-absorption in the visible light range and/or the ultraviolet range and/or the infrared range, etc., at the dosages suggested by the suppliers of the additives and at any rate known to the experts in the art.
On the other hand, as regards resistance to photo-degradation, the light stabiliser added to the polyolefin-based mixture comprises HALS, which are preferably oligomeric or polymeric and of the secondary and tertiary type and also methylated or at any rate modified and substituted, and is constituted in a preferred composition variant by those substances only. Preferably, the light stabiliser is constituted by methylated HALS or by sterically hindered aminoxyamines, also known as NOR-HALS, in order to make use of the lower basicity thereof.
According to the invention, an effective amount of TPU is also added to the basic polymer mixture. The TPU may be either of the aromatic type or of the aliphatic type, with a polyester or polyether structure. However, the use of aliphatic, polyester or polyether TPU is preferred because aromatic TPU may give rise, as a result of photo-oxidative reactions, to chromophore groups which tend to confer a brownish yellow colour on the film. Films to which aromatic TPU, which is per se advantageously less expensive, is added, could also be used in particular applications where a possible colouring does not have negative effects. TPUs having a polyester structure are generally less expensive, while TPUs based on polyether generally exhibit greater resistance to hydrolysis. In the polymer mixture used to produce the film according to the invention, the TPU and the HALS are present in a ratio by weight of from 2:1 to 25: 1. In particular, the TPU is added to the polymer mixture in such a manner as to attain a fraction by weight of from 5% to 30%, preferably from 7% to 15%, while, for their part, the HALS are added in such a manner as to attain a fraction by weight of from 0.2% to 2.5%, preferably from 0.8% to 1.6%, with respect to the film. It is known that the polyolefin family and the TPUs have physico-chemical characteristics which are relatively diverse with respect to each other, so that, in liquid phase, the two compounds are poorly miscible in each other. This means that they are mixed homogeneously with each other by physical mixing inside an extruder, into which they are both fed in the predefined proportion, making use of the mechanical action of the screw in which a transport and compression region, a mixing region and a final compression region are combined. Preferably, the TPU and the polyolefin base are selected in such a manner as to have comparable melting points, differing by less than 400C, and similar apparent viscosities in the range of the speed gradients usual for extrusion processes. Examples
A film based on aliphatic polyester TPU and four films based on EVA/C, having, respectively, the formulations indicated below, were prepared: Specimen 1 : aliphatic polyester TPU: 98.0% antiblocking agent: 2.0%
Specimen 2:
EVA/C with 9% of VA 90.5% aromatic polyester TPU 8.0%
HALS 1.0% antiblocking agent 0.5%
Specimen 3:
EVA/C with 9% of VA 90.5% aliphatic polyester TPU 8.0%
HALS 1.0% antiblocking agent 0.5%
Specimen 4:
EVA/C with 9% of VA 80.5% aliphatic polyester TPU 18.0% HALS 1.0% antiblocking agent 0.5%
Specimen 5:
EVA/C with 9% of VA 98.5%
HALS 1.0% antiblocking agent 0.5%
The formulations were mixed in a drive extruder of the Bandera single- screw type having a diameter of 45 mm, L/D=25, driven at an extrusion rate of 40 rev/min, with an internal temperature profile increasing from 1350C to 1800C, and were then extruded in such a manner as to form respective films having a thickness of 0.150 mm, numbered 1 to 5, from which were obtained the samples for the accelerated ageing tests in a SAIREM-SEPAP chamber, at a constant temperature of 6O0C. In order to determine the conclusion of each test, the criterion of reduction to 50% of the initial value for elongation at break in tensile stress tests according to EN ISO 527-1 and EN ISO 527-3 was used.
Specimen 1: did not reach the 750 hours of exposure, corresponding to the first sampling.
Specimen 2: test interrupted at 750 hours of exposure owing to the intense brownish yellow colour exhibited by the specimen.
Specimen 3: from 3,000 to 3,500 hours
Specimen 4: more than 3,500 hours
Specimen 5: from 2,500 to 3,000 hours.
A practical use check was carried out only for the formulation corresponding to Specimen 4, which was the best result of the test, using as a comparison (control) the formulation of Specimen 5 and producing in an industrial-scale plant coextruded films having a thickness of 0.150 mm, which were installed from the month of October 2003 on a seVies of individual tunnels, three per type, in a test field belonging to the Applicant located in a climate zone of the northern hemisphere with irradiation intensity corresponding to approximately 130 kLy/year.
All of the films of type 5 were found to be still sound after two years, but with a longitudinal elongation at break of approximately 50% of the initial value.
The films of type 4 were found to be sound even at the end of the third winter of use, but with residual mechanical characteristics which unexpectedly suggest that they might last at least another year, with an increase of from 30 to 50% in resistance to photodegradation with respect to the films of the conventional type used as controls.
The present invention therefore achieves the object proposed of providing a polymer film having greater resistance to polymer degradation caused by exposure to sunlight. At the same time, the invention offers numerous other advantages for use, including the fact that the polymer film so obtained has, compared with a conventional polyolefin-based film, improved characteristics of elasticity and tear resistance and greater IR efficiency (greenhouse effect), evaluated as absorption of radiation in the far infrared range, wavelengths of from 7,000 to 13,000 nm, in accordance with the standard EN 13206:2001. In the example given, in fact, the IR efficiency measured on specimens of type 5 film was 75%, against values higher than 85% for the type 4 film obtained in accordance with the present invention.

Claims

C L A I M S
1. A polymer film, particularly for use as a cover in agriculture, comprising at least one layer of polyolefin-based polymer material in which a light stabiliser based on hindered amines (HALS) is dispersed, characterised in that arc effective amount of thermoplastic polyurethane is also dispersed in the layer of polymer material.
2. A film according to claim 1, wherein the thermoplastic polyurethane and the light stabiliser based on hindered amines are present in the layer in a ratio by weight of from 2: 1 to 25: 1.
3. A film according to claim 1 or 2, wherein the thermoplastic polyurethane is present in a fraction by weight of from 5% to 30% with respect to the film and the light stabiliser based on hindered amines is present in a fraction by weight of from 0.2% to 2.5% with respect to the film.
4. A film according to claim 3, wherein the thermoplastic polyurethane is present in a fraction by weight df from 7% to 15% with respect to the film and the light stabiliser based on hindered amines is present in a fraction by weight of from 0.8% to 1.6% with respect to the film.
5. A film according to one or more of the preceding claims, wherein the thermoplastic polyurethane is of the aliphatic type.
6. A film according to one or more of the preceding claims, wherein the thermoplastic polyurethane has a polyester structure.
7. A film according to one or more of claims 1 to 5, wherein the thermoplastic polyurethane has a polyether structure.
8. A film according to one or more of the preceding claims, wherein the layer of polymer material is based on an ethylene-vinyl acetate copolymer (EVA/C) or an ethylene-butyl acrylate copolymer (EBA/C).
9. A film according to one or more of the preceding claims, wherein the layer of polymer material is constituted by a mixture based on an ethylene-vinyl acetate copolymer (EVA/C) or an ethylene-butyl acrylate copolymer (EBA/C) with low density polyethylene (LDPE) or linear low density polyethylene (LLDPE), in any mixture ratio.
10. A process for the production of a film for use as a cover in agriculture, comprising the unitary operation of mixing at high temperature a polyolefin base with a light stabiliser and extruding the mixture to obtain the film, characterised by adding an effective amount of thermoplastic polyurethane (TPU) during the mixing stage.
11. A method for improving the resistance to photo-degradation of a film comprising a layer of polyolefin-based polymer material in which a light stabiliser based on hindered amines is dispersed, characterised in that an effective amount of thermoplastic polyurethane is dispersed in the polymer material.
12. A method according to claim 11, wherein the thermoplastic polyurethane and the light stabiliser based on hindered amines are present in a ratio by weight of from 2: 1 to 25: 1.
13. A method according to claim 11 or 12, wherein the thermoplastic polyurethane is present in a fraction by weight of from 5% to 30% with respect to the film and the light stabiliser based on hindered amines is present in a fraction by weight of from 0.2% to 2.5% with respect to the film.
14. A method according to one or more of claims 11 to 13, wherein the thermoplastic polyurethane is of the aliphatic type.
15. A method according to one or more of claims 11 to 14, wherein the thermoplastic polyurethane has a polyester structure.
16. A method according to one or more of claims 11 to 14, wherein the thermoplastic polyurethane has a polyether structure.
PCT/IT2006/000631 2006-08-29 2006-08-29 Polymer film for use as a cover in agriculture WO2008026229A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/IT2006/000631 WO2008026229A1 (en) 2006-08-29 2006-08-29 Polymer film for use as a cover in agriculture
SM200900019T SMP200900019B (en) 2006-08-29 2009-03-26 Polymeric film for use as a cover in agriculture

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IT2006/000631 WO2008026229A1 (en) 2006-08-29 2006-08-29 Polymer film for use as a cover in agriculture

Publications (1)

Publication Number Publication Date
WO2008026229A1 true WO2008026229A1 (en) 2008-03-06

Family

ID=37909690

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IT2006/000631 WO2008026229A1 (en) 2006-08-29 2006-08-29 Polymer film for use as a cover in agriculture

Country Status (2)

Country Link
SM (1) SMP200900019B (en)
WO (1) WO2008026229A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2163570A1 (en) * 2008-09-10 2010-03-17 Rohm and Haas France SA Urethane Arcrylic Blends
CN108912468A (en) * 2018-05-29 2018-11-30 厦门协四方工贸有限公司 A kind of anti-aging bubble chamber film and its moulding process
CN109721984A (en) * 2017-10-31 2019-05-07 丹阳博亚新材料技术服务有限公司 A kind of heat-insulated antifog greenhouse film
EP3578036A1 (en) 2018-06-06 2019-12-11 Thrace Nonwovens & Geosynthetics S.A. Development of a flame retardant groundcover fabric for greenhouses
WO2022023782A1 (en) * 2020-07-27 2022-02-03 Plastika Kritis S.A. Films for agricultural structures
CN114347609A (en) * 2022-01-10 2022-04-15 高碑店市立信神农科技发展有限责任公司 Low-temperature-resistant long-life greenhouse film

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57168928A (en) * 1981-04-10 1982-10-18 Toyo Soda Mfg Co Ltd Agricultural film
EP0612795A1 (en) * 1993-02-24 1994-08-31 CONSTAB POLYMER-CHEMIE GmbH & Co. Light stabilized polymer compositions
EP1184416A1 (en) * 2000-08-29 2002-03-06 Ciba SC Holding AG Method for reducing dust deposition on polyolefin films
JP2003000076A (en) * 2001-06-20 2003-01-07 Mitsubishi Chem Mkv Co Polyolefin-based resin film for agriculture
WO2005111142A1 (en) * 2004-05-13 2005-11-24 Oleg Leonidovich Kulikov Thermoplastic polymer material

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57168928A (en) * 1981-04-10 1982-10-18 Toyo Soda Mfg Co Ltd Agricultural film
EP0612795A1 (en) * 1993-02-24 1994-08-31 CONSTAB POLYMER-CHEMIE GmbH & Co. Light stabilized polymer compositions
EP1184416A1 (en) * 2000-08-29 2002-03-06 Ciba SC Holding AG Method for reducing dust deposition on polyolefin films
JP2003000076A (en) * 2001-06-20 2003-01-07 Mitsubishi Chem Mkv Co Polyolefin-based resin film for agriculture
WO2005111142A1 (en) * 2004-05-13 2005-11-24 Oleg Leonidovich Kulikov Thermoplastic polymer material

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2163570A1 (en) * 2008-09-10 2010-03-17 Rohm and Haas France SA Urethane Arcrylic Blends
EP2163571A1 (en) * 2008-09-10 2010-03-17 Rohm and Haas Company Urethane acrylic blends
US8455099B2 (en) 2008-09-10 2013-06-04 Rohm And Haas Company Urethane acrylic blends
AU2009212774B2 (en) * 2008-09-10 2014-11-13 Rohm And Haas Company Urethane acrylic blends
CN109721984A (en) * 2017-10-31 2019-05-07 丹阳博亚新材料技术服务有限公司 A kind of heat-insulated antifog greenhouse film
CN108912468A (en) * 2018-05-29 2018-11-30 厦门协四方工贸有限公司 A kind of anti-aging bubble chamber film and its moulding process
EP3578036A1 (en) 2018-06-06 2019-12-11 Thrace Nonwovens & Geosynthetics S.A. Development of a flame retardant groundcover fabric for greenhouses
GR20180100240A (en) * 2018-06-06 2020-02-13 Thrace Nonwovens & Geosynthetics Αβεε Μη Υφαντων Υφασματων Και Γεωσυνθετικων Προϊοντων Develop,ent of a flame retardant groundcover fabric for greenhouses
GR1009783B (en) * 2018-06-06 2020-07-07 Thrace Nonwovens & Geosynthetics Αβεε Μη Υφαντων Υφασματων Και Γεωσυνθετικων Προϊοντων Develop,ent of a flame retardant groundcover fabric for greenhouses
WO2022023782A1 (en) * 2020-07-27 2022-02-03 Plastika Kritis S.A. Films for agricultural structures
CN114347609A (en) * 2022-01-10 2022-04-15 高碑店市立信神农科技发展有限责任公司 Low-temperature-resistant long-life greenhouse film

Also Published As

Publication number Publication date
SMP200900019B (en) 2010-01-19
SMAP200900019A (en) 2009-05-11

Similar Documents

Publication Publication Date Title
WO2008026229A1 (en) Polymer film for use as a cover in agriculture
EP3654756B2 (en) Greenhouse screen
ES2703705T3 (en) Stabilized resin composition
Al-Salem Influence of natural and accelerated weathering on various formulations of linear low density polyethylene (LLDPE) films
WO2013152100A1 (en) Stabilized polyolefins having increased agrochemical and uv resistance and methods of use
KR20060047208A (en) Process for producing transparent material made of polylactic acid and transparent material made of polylactic acid
EP3762451B1 (en) Artificial turf fiber with uv protection substances
DE60105484T2 (en) Polyolefin film compositions having anti-fog properties
EP1118635A2 (en) Tranparent, flame retardant, UV-stable film of a crystallisable thermoplastic material
Singh Butola et al. Photostability of HDPE filaments stabilized with UV absorbers (UVA) and light stabilizers (HALS)
DE10007673A1 (en) Opaque white film used for interiors, displays and coatings, comprises a crystallizable thermoplastic, barium sulfate pigment, UV stabilizer(s) and optical brightener(s)
DE10007672A1 (en) White-opaque, flame-retardant, UV-stabilized film with low transparency made of a crystallizable thermoplastic
KR101607153B1 (en) Resin composition for industry protective film using UV master batch and Manufacturing protective film using the same
WO2001053394A1 (en) Transparent films made of cristallizable thermoplastic materials, production method and utilization thereof
CN1132219A (en) Agricultural fluorescent film having excellent resistance to weathering
CN113563661B (en) Long-acting weather-resistant master batch for agricultural film, and preparation method and application thereof
JP4015489B2 (en) Polyolefin resin composition for extrusion lamination with excellent weather resistance
CN108099325B (en) Degradable biaxially oriented polypropylene tape base film and preparation method thereof
Montagna et al. Comparative study of degradation of PP modified with an organic pro-degradant subjected to natural and artificial ageing
KR0143137B1 (en) Low density polyethylene film
CN108912468B (en) Anti-aging bubble film and forming process thereof
GB2247681A (en) A photo-degradable plastics material
KR20000042841A (en) Polyolefin-based film composition for agriculture excellent in near ultraviolet rays shielding property
KR101655183B1 (en) Resin composition of controlling scattering light wavelength and mushroom cultivating envelope using the same
EP1276794B1 (en) Dyed, low-flammability, uv-stable, thermoformable film consisting of a crystallizable thermoplastic, method for producing said film and use thereof

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 06796271

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase

Ref country code: DE

NENP Non-entry into the national phase

Ref country code: RU

122 Ep: pct application non-entry in european phase

Ref document number: 06796271

Country of ref document: EP

Kind code of ref document: A1