AU2013369481B2

AU2013369481B2 - Plastic film

Info

Publication number: AU2013369481B2
Application number: AU2013369481A
Authority: AU
Inventors: Wolfgang BOLOM; Jan-Thorsten VOLLMER; Martin WILDINGER
Original assignee: Coveris Flexibles Austria GmbH
Current assignee: Coveris Flexibles Austria GmbH
Priority date: 2012-12-27
Filing date: 2013-12-16
Publication date: 2016-11-24
Anticipated expiration: 2033-12-16
Also published as: NZ709323A; AT513739A4; AU2013369481A1; PL2938489T3; AT513739B1; EP2938489A1; SI2938489T1; WO2014102080A1; DK2938489T3; ES2908058T3; EP2938489B1; PT2938489T

Abstract

The invention relates to a plastic film (1) for wrapping silage material (2), comprising a single-ply or multi-ply outer layer (3), a single-ply or multi-ply inner layer (4), and an intermediate layer (5) arranged between the outer layer (3) and the inner layer (4). The outer layer (3), the inner layer (4), and the intermediate layer (5) are designed to be gas-tight and at least partly translucent, preferably completely translucent, in the visible spectrum.

Description

2013369481 12 Oct 2016 1

PLASTIC FILM

The invention concerns a plastic film for the wrapping of 5 silage material, comprising a single-ply or multi-ply outer layer, a single-ply or multi-ply inner layer, as well as an intermediate layer arranged between the outer and the inner layer. 10 The ensiling of agricultural fodder such as grass, clover and oats or similar is a well-known process in which the feed material is preserved through lactic acid fermentation under the exclusion of air. For this purpose it is also known to compress the agricultural fodder into 15 bales and wrap it in a plastic film. This creates silage bales that can be stored by the farmer for a prolonged period of time for later use. Besides using the silage material to feed livestock, it may also be used as substrate for biogas plants. 20

Plastic films for producing silage bales must be gas-tight in order to prevent the surrounding air from penetrating the silage, which would encourage the formation of mould. To achieve this, commercially 25 available film is usually made to be elastic and is wrapped multiple times around the silage material. Moreover, plastic films known from the prior art are usually dyed to prevent light from entering into the inner layers of the film and deteriorating the gas-30 tightness of these layers over time. The usual colours are black, white and green. 2 2013369481 12 Oct 2016

These types of film are usually made of multiple layers and comprise in particular an inner layer, an intermediate layer and an outer layer. One problem with conventional, dyed silage film is, however, that it is 5 impossible for the farmer to tell from the outside what the condition of the silage is. It may be, for example, that the fodder is already mouldy throughout without being able to see this from the outside. Moreover, the dying involves the admixture of polyolefins, which adds 10 to the cost. The disposal of dyed materials causes additional problems.

Embodiments of the present disclosure aim to provide a plastic film for making silage bales which is durable and 15 gas-tight but still permits the farmer to assess the fodder contained therein, and which is simple and cost-effective to manufacture.

Any discussion of documents, acts, materials, devices, 20 articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before 25 the priority date of each claim of this application.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, 30 integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. 3 2013369481 12 Oct 2016

According to a first aspect there is provided a silage film, comprising - a single-ply or multi-ply outer layer, - a single-ply or multi-ply inner layer, 5 - as well as an intermediate layer located between the outer layer and the inner layer, wherein the outer layer, the inner layer and the intermediate layer are at least partially, preferably fully, translucent in the visible light 10 spectrum and are gas-tight; - wherein the outer layer is comprised of at least one of the substances LLDPE C8, LLDPE C6, mLLDPE C6, LDPE or mLLDPE C8, LLDPE C4, mLLDPE C4 or copolymers of these substances; 15 - wherein the inner layer is comprised of at least one of the substances LLDPE C8, LLDPE C6, mLLDPE C6, LDPE, mLLDPE C8, LLDPE C4, mLLDPE C4, copolymers of these substances, polyisobutylene, ethylene vinyl acetate, or ethylbutylacetate; and 20 - wherein the intermediate layer is comprised of at least one of the substances LLDPE C8, LLDPE C6, mLLDPE C6, LDPE, mLLDPE C8, LLDPE C4, mLLDPE C4 or copolymers of these substances. 25 According to a second aspect, there is provided a silage bale for the storage of silage material, in particular agricultural products such as straw, hay and maize, wherein the silage bale comprises a silage film according to the first aspect. 30

According to a third aspect, there is provided application of the silage film according to the first aspect for the production of a silage bale. 4 2013369481 12 Oct 2016

The translucence may only be provided in a certain wavelength range, preferably in the range of the visible spectrum, whereas other wavelengths, for example ultraviolet or infrared light, may be blocked out. The 5 individual layers may also exhibit varying translucence or varying gas-tightness respectively. The gas-tightness of six layers of non-oriented film may be in particular < 1400 cm3/(m2 x 24 h) according to DIN EN 14932:2007-03, version 14932:2006 in a test according to the method from 10 ANNEX A of the standard ISO 15105-2:2003.

Moreover, provision can be made, according to the invention, to add UV stabilisers and/or UV blockers to the film. 15

As a result of the transparent or partially translucent film according to the invention and the admixture of suitable UV stabilisers and/or UV blockers, tests of silage bales have shown that lactic acid fermentation as 20 well as storage of the baled fodder is possible for a period of up to one year.

The advantage for the farmer is that the condition of the fodder can be assessed at any time, and the manufacture 25 of the plastic film is simplified since it requires no additives to achieve colouring.

When applying the plastic film according to the invention, the fodder bale is first wrapped with a net 30 before it is wrapped with 4 to 6 layers of film according to the invention. This produces an air-tight coverage of the enclosed organic matter (grass, maize etc.), which causes lactic acid fermentation. 2013369481 12 Oct 2016 30 5

All layers of the plastic film may be produced with UV stabilisers and/or UV blockers. Benzophones may preferably be used as UV blockers. The layers of the plastic film may comprise a UV stabiliser, preferably 5 HALS at a quantity of 3000 ppm to 10000 ppm, preferably 5000 to 8000 ppm. Moreover, the light spectrum, which is permitted to pass through or which is blocked respectively, can be adjusted through the admixture of UV blockers . 10

The outer layer of the plastic film may be a composition of LLDPE C8, LLDPE C6, mLLDPE C6, LDPE, mLLDPE C8, LLDPE C4, mLLDPE C4 and/or copolymers of these substances. The outer layer may also be multi-ply, in which case the 15 composition relates to the sum of the layers. The outer layer may also contain a UV blocker.

The inner layer of the plastic film may be a composition of LLDPE C8, LLDPE C6, mLLDPE C6, LDPE, mLLDPE C8, LLDPE 20 C4, mLLDPE C4, copolymers of these substances, polyisobutylene, ethylene vinyl acetate, or ethylbutyl-acetate. The inner layer may also be multi-ply, in which case the composition relates to the sum of the layers. 25 The intermediate layer of the plastic film may be a composition of LLDPE C8, LLDPE C6, mLLDPE C6, LDPE, mLLDPE C8, LLDPE C4, mLLDPE C4 or copolymers of these substances. The intermediate layer may be multi-ply, in which case the composition relates to the sum of the layers . 6 2013369481 12 Oct 2016

The thickness of the plastic film may be between 10 pm and 50 pm, preferably between 22 pm and 27 pm, in particular 25 pm. 5 The thickness of the intermediate layer may be 40% to 70%, preferably 50% to 60% of the overall thickness of the plastic film. The thickness of the outer layer may be 10% to 25%, preferably 20% of the overall thickness of the plastic film. The thickness of the inner layer may be 10 10% to 35%, preferably 15% to 25% of the overall thickness of the plastic film. Should the layers be multi-ply, the figures relate to the sum of the thicknesses of the respective partial layers. 15 Moreover, according to the invention it is possible for the film to have more than three, preferably five layers. The outer layer may comprise a first partial outer layer and a second partial outer layer, and/or the inner layer may comprise a first partial inner layer and a second 20 partial inner layer. In this instance the second partial outer layer may be applied between the first partial outer layer and the intermediate layer, and the first partial inner layer may be applied between the intermediate layer and the second partial inner layer. 25

All layers may comprise a UV stabiliser, preferably HALS. Moreover, all layers may comprise a UV blocker.

The plastic film may also be made to have elastic 30 properties and a maximum elongation of at least 300%, preferably 390%, as well as a reversible wrap elongation of 30% to 150%. In longitudinal direction the plastic film may have an elongation at break of more than 300% 7 2013369481 12 Oct 2016 and in transverse direction of more than 300%, and the tensile strength in longitudinal direction is more than 20 N/mm2 and in transverse direction more than 20 N/mm2. 5 The invention concerns, furthermore, a silage bale for storing silage material, in particular of agricultural products like straw, hay and maize, in which the silage bale comprises a plastic film according to the invention, as well as the application of the plastic film according 10 to the invention for the production of silage bales.

Further characteristics according to the invention become apparent from the claims, the drawings and the description. 15 20 25

The following provides a more detailed explanation of the invention by way of exemplary embodiments. Shown are in:

Fig. 1 a first exemplary embodiment of a plastic film according to the invention;

Fig. 2 a second exemplary embodiment of a plastic film according to the invention;

Fig. 3 an axonometric representation of an upright silage bale, wrapped in a plastic film according to the invention;

Fig. 4 a cross-section of a silage bale, wrapped in a plastic film according to the invention.

Fig. 1 shows a first exemplary embodiment of a plastic 30 film 1 according to the invention. The plastic film 1 comprises an outer layer 3, an inner layer 4 and an intermediate layer 5. The outer layer 3 is made up of 92% mLLDPE and 8% HALS UV stabiliser masterbatch. The term 8 2013369481 12 Oct 2016 masterbatch designates the type of plastic granulate used. The thickness of the outer layer 3 is 20% of the overall thickness of the multi-ply plastic film. It is the outer boundary of the multi-ply plastic film. The 5 internal side of the outer layer 3 is adjacent to the intermediate layer 5.

The intermediate layer 5 consists of a blend analogous to the outer layer as well as the inline edge trim return. 10 The lateral roll ends are trimmed off during manufacture and returned to the extruder; this creates the material called edge trim return.

The thickness of the intermediate layer 5 is 60% of the 15 overall thickness of the multi-ply plastic film. The internal side of the intermediate layer 5 is adjacent to the inner layer 4. The inner layer 4 is comprised of 90% ethylene vinyl acetate, 5% HALS UV stabiliser masterbatch and 5% polyisobutylene. The thickness of the inner layer 20 4 is 20% of the overall thickness of the multi-ply plastic film. In the wrapped state, the inner layer 4 is the inner boundary of the multi-ply plastic film 1 to the adjacent layer of film. 25 Fig. 2 shows a second exemplary embodiment of a plastic film 1 according to the invention. The outer layer 3 comprises the first partial outer layer 6 and the second partial outer layer 7. The first partial outer layer 6 is the outermost layer of the film and consists of 92% 30 mLLDPE and 8% HALS UV stabiliser masterbatch. The thickness of the first partial outer layer 6 is 10% of the overall thickness of the multi-ply plastic film. The second partial outer layer 7 is located between the first 9 2013369481 12 Oct 2016 partial outer layer 6 and the intermediate layer 5. The second partial outer layer 7 consists of 95% mLLDPE and 5% HALS UV stabiliser. 5 The thickness of the second partial outer layer 7 is 10% of the overall thickness of the multi-ply plastic film. The intermediate layer 5 is located underneath the second partial outer layer 7. It consists of a blend that is analogous to that of the second partial outer layer, as 10 well as the inline edge trim granulate. The regranulate may comprise the components of all layers. Its share of the overall thickness of the multi-ply plastic film 1 is 50%. The inner layer 4, which consists of the first partial inner layer 8 and the second partial inner layer 15 9, is located underneath the intermediate layer 5.

The first partial inner layer 8, which is located between the intermediate layer 5 and the second partial inner layer 9, consists of 85% mLLDPE, 10% LDPE and 5% HALS UV 20 stabiliser masterbatch. Its thickness is 10% of the overall thickness of the multi-ply plastic film 1. The second partial inner layer 9, which is adjacent to the next layer of film, forms the innermost layer of the multi-ply plastic film. It consists of 92% LLDPE and 8% 25 polyisobutylene. The thickness of the second partial inner layer 9 is 20% of the overall thickness of the multi-ply plastic film, and it is the only layer that does not contain HALS UV stabiliser. 30 Sufficient impermeability of the film can preferably be established through standardised methods for impermeability testing. For example DIN EN 14932:2007-03, version 14932:2006 specifies an impermeability of 2013369481 12 Oct 2016 20 10 < 1400 cm3/ (m2 x 24 h) . Such a specification can be achieved according to the method provided in ANNEX A of the standard ISO 15105-2:2003 with preferably 6 layers of the non-oriented film. 5

Fig. 3 depicts an axonometric representation of an upright silage bale 10, which is wrapped in an exemplary embodiment of a plastic film 1 according to the invention. The silage bale has the approximate form of a 10 cylinder. The cross-sectional plane for Fig. 4 is shown.

Fig. 4 shows a cross-section of a silage bale 10, which is wrapped in an exemplary embodiment of a plastic film 1 according to the invention. The silage material 2 is 15 wrapped approximately 4 to 10 times with the multi-ply plastic film 1. For application purposes the film is wound onto rolls. The outer layers 3, 6 are located on the outside of said roll. However, when wrapping the silage bale 10 the film is applied such that the outer layers 3, 6 are located on the inside of silage bale 10.

The inner layers 4, 9 of film 1 are facing outwards on silage bale 10. 2013369481 12 Oct 2016

LIST OF REFERENCE NUMBERS 5 10 11 1 Plastic film 2 Silage material 3 Outer layer 4 Inner layer 5 Intermediate layer 6 First partial outer layer 7 Second partial outer layer 8 First partial inner layer 9 Second partial inner layer 10 Silage bale

Claims

1. A silage film for wrapping of silage material, comprising - a single-ply or multi-ply outer layer, - a single-ply or multi-ply inner layer, - as well as an intermediate layer located between the outer layer and the inner layer, wherein the outer layer, the inner layer and the intermediate layer are at least partially, preferably fully, translucent in the visible light spectrum and are gas-tight; - wherein the outer layer is comprised of at least one of the substances LLDPE C8, LLDPE C6, mLLDPE C6, LDPE or mLLDPE C8, LLDPE C4, mLLDPE C4 or copolymers of these substances; - wherein the inner layer is comprised of at least one of the substances LLDPE C8, LLDPE C6, mLLDPE C6, LDPE, mLLDPE C8, LLDPE C4, mLLDPE C4, copolymers of these substances, polyisobutylene, ethylene vinyl acetate, or ethylbutylacetate; and - wherein the intermediate layer is comprised of at least one of the substances LLDPE C8, LLDPE C6, mLLDPE C6, LDPE, mLLDPE C8, LLDPE C4, mLLDPE C4 or copolymers of these substances.

2. A silage film according to any one of the preceding claims, wherein the layers comprise a UV stabiliser, preferably HALS, at a quantity of 3000 ppm to 10000 ppm, preferably 5000 to 8000 ppm.

3. A silage film according to any one of the preceding claims, wherein the layers comprise a UV blocker at a quantity of up to 5000 ppm.

4. A silage film according to any one of the preceding claims, wherein the thickness of the silage film is between 10 pm and 50 pm, preferably between 20 pm and 27 pm, in particular 25 pm.

5. A silage film according to any one of the preceding claims, wherein the thickness of the intermediate layer is 40% to 70%, preferably 50% to 60% of the overall thickness of the silage film.

6. A silage film according to any one of the preceding claims, the thickness of the outer layer is 15% to 25%, preferably 20% of the overall thickness of the silage film.

7. A silage film according to any one of the preceding claims, wherein the thickness of the inner layer is 10% to 35%, preferably 15% to 25% of the overall thickness of the silage film.

8. A silage film according to any one of the preceding claims, wherein the outer layer comprises a first partial outer layer and a second partial outer layer, and the inner layer comprises a first partial inner layer and a second partial inner layer, in which the second partial outer layer is located between the first partial outer layer and the intermediate layer, and the first partial inner layer is located between the intermediate layer and second partial inner layer.

9. A silage film according to claim 8, wherein the first partial inner layer comprises a UV stabiliser, preferably HALS, and the second partial inner layer has no UV stabiliser.

10. A silage film according to claim 8 or 9, wherein the first partial inner layer and the second partial inner layer comprise a UV blocker.

11. A silage film according to any one of the preceding claims, wherein the silage film is made to be elastic and provides a maximum elongation of at least 200%, as well as a reversible wrap elongation of 30% to 150%.

12. A silage film according to claim 11, wherein the silage film provides a maximum elongation of at least 390%.

13. A silage film according to any one of the preceding claims, wherein the silage film has an elongation at break in longitudinal direction of more than 300% and in transverse direction more than 300%, where the tensile strength is more than 20 N/mm2 in longitudinal direction and more than 20 N/mm2 in transverse direction.

14. Silage bale for the storage of silage material, in particular agricultural products such as straw, hay and maize, wherein the silage bale comprises a silage film according to any one of the preceding claims .

15. Application of the silage film according to any one of the claims 1 to 16 for the production of a silage bale .