Patent Application
20100229462
Plastic film products have penetrated every sector of the agriculture market in the United States and throughout the world. One of the greatest uses of agricultural films is specifically the one used for mulching. In some cases though, there can be some very serious environmental problems once the film usage is completed. However, these mulching films are necessary in today's “plasticulture”. These films provide a local greenhouse affect by raising the soil temperature of the area covered. The humidity of the soil is well maintained to such level that plant seed germination and root growth is greatly enhanced.
In addition, there is a great savings in water usage since the mulch film prevents evaporation of the water. Another benefit is that chemicals such as fertilizers, pesticides, and herbicides are more easily available to the plants or seeds when protected by the mulch films. These films also greatly reduce weeds that would otherwise fight the intended crop for water and soil nutrients.
However, these mulching films despite all the benefits are causing grave disposal problems to farmers. Removal of these films is necessary because a residual film hampers the next cultivating crop for the farm operations. The previous film suffocates the next crop's root system and presents a great problem for the farm equipment. Therefore, the removal of these films is a necessity and done at a very high price. Burning of the film is severally restricted in most localities especially in the US when dealing with the EPA and since the films may contain residual pesticides and herbicides, burning is definitely out of the question. Exporting these residual films containing dirt, pesticides, and herbicides to China is no longer a valid option. Land filling is expensive and the films trap air which takes up more space. Therefore disposing of these films in a landfill this is not a viable option either.
In most cases the residual film is gathered and collected in a large pile to slowly degrade with time. This option has some inherent problems since pieces of the film can be carried by the wind and in turn, contaminating the landscape and other farmer's land, which can lead to legal issues.
In response, Cerowna LP has developed and designed a controlled photo, chemical, and thermal degradable film system which can incorporate bio degradable technology that addresses all of the above
A method is taught for increase crop yield and weight per acre comprising the steps of providing a degradable mulch film, then laying the degradable mulch film over a cleared field, and covering a portion of the degradable mulch film with soil. The mulch film is made up a below ground degradable film (B) and an above ground degradable film (A), film B is co-extruded with film A and another film B to have a BAB structure where the films B and film A have a single layer feel. Film B is a plastic resin treated with an acid and having an additive that supplies a source of oxygen, and a metal stearate. Film A is a plastic resin an additive for aiding decomposition and an additive to retard decomposition.
For the purpose of illustrating the invention, there is shown in the drawings a form that is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.
The invention is a method for increase crop yield and weight per acre by providing a degradable mulch film comprised of a below ground degradable film (B) and an above ground degradable film (A). This degradable mulch film 10,
Film A is made from a plastic resin and having an additive for aiding decomposition and an additive for promoting decomposition.
The plastic resin of film A can be any number of resins including: polypropylene (PP), as a homopolymer or a copolymer as well as syndiotactic PP; polyethylene (PE), including low density PE (LDPE), linear low density PE (LLDPE); condensation polymers such as polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycarbonate (PC), PE/LDPE blends, PE/masterblends and combinations thereof. The plastic resin makes up from 99.96% to 90% by weight of the above ground resin A. The additive for aiding decomposition is a metal prodegradant. Examples of metal prodegradents include stearates such as cobalt, cerium, iron, manganese, zirconium, nickel and combinations thereof. The additive for aiding decomposition makes up from 0.02% to 5% by weight of the above ground resin A. The additive to retard decomposition is an additive can be an UV stabilizer, metal oxides, primary and secondary antioxidants like butylated hydroxytoluene (BHT) or lonol and Irganox 1010, Irganox 1076, Irgafos 168, Sandostab PEPQ. The additive to retard decomposition makes up from 0.02% to 5% by weight of the above ground resin A.
Film B is made from a natural resin or a plastic resin, which is treated with an acid and a source of oxygen and a metal stearate.
The plastic resin of film B is a resin can be any number of resins including: polypropylene (PP), as a homopolymer or a copolymer as well as syndiotactic PP; polyethylene (PE), including low density PE (LDPE), linear low density PE (LLDPE); condensation polymers such as polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycarbonate (PC). This resin can also be a bio resin such as polylactic acid (PLA), polycaprotone, mater-B or other bio-resins that meet the ASTM 6400 composting requirements and combinations of these resins thereof. If a bio-resin is used that meet the ASTM 6400 composting requirements it is not necessary to add an acid and a source of oxygen and a metal stearate. However one or more of these additives could be added to help in the decomposition process. The plastic resin or bio-resin makes up from 98.98% to 75% by weight of the below ground resin B. The acid, which the plastic resin is treated with, can include but is not limited to: acrylic acid, methacylic acid, maleic anhydride, vinyl acetate, ethyl acetate, citric acid and combinations thereof. This acid can be added in a range of 2% to 20% by weight. Note that the polymer may also include an acid polymer examples are ethylene ethyl acetate (EEA), ethylene maleic anhydride copolymer (EMA), ethylene vinyl acetate copolymer (EVA). An example of such a polymer is Nucrel from DuPont 1202 HC with 11.5% by weight of methacylic acid in a polyethylene. The additive for aiding decomposition is a metal prodegradant. Examples of metal prodegradents include stearates such as cobalt, cerium, iron, manganese, zirconium, nickel and combinations thereof. The additive for aiding decomposition makes up from 0.02% to 5% by weight of the below ground resin B. The additive that is a source of oxygen can be a pigment that contains oxygen, an oxidizer or combinations thereof. This is not limited to either organic or inorganic pigments. An example of an inorganic pigment, which contains oxygen is iron oxide, and example of a synthetic pigment is syn-oxHB-1053 Black from the Hoover Color Corporation, and an example of an oxidizer is potassium permanganate. The additive that is a source of oxygen makes up from 1% to 40% by weight of the above ground resin B.
This mulch film is laid in a farmer's or grower's field as long sheets, with most of the mulch film positioned above ground, the above ground degradable film A,
This unique mulch film allows for a ground covering for a specified growing season but then also degrades at the desired time so that it does not have to be taken up, and can be plowed back into the field where it will finish degrading. As it is made up from two materials the mulch film is then capable of decomposing in both an above ground and a below ground environment. The above ground film has the benefit of oxygen in the air as well as sunlight, which provides ultraviolet rays and heat energy to aid in the decomposition. Therefore the degradation method of the above ground degradable film is a combination of an oxo-degradation, thermal degradation, ultraviolet degradation. Below the ground the portion of the mulch, which is covered by soil does not have ready access to oxygen or ultraviolet rays, and must relay on heat energy, micro organisms, fungi and the chemical composition of the below ground resin to supply the needed elements to biodegrade. The below ground degradation is a combination of thermal degradation, chemical degradation and biodegration.
The mulch film can be distributed in roll form so that it can be unrolled into long sheets on the field. The plastic used will not sticking to itself. This non-stick function makes it easy to unroll the mulch film right to the core. The rolls can be made in any length, but rolls that cover 4,000, 6,000 and 8,000 feet provide the benefit of matching farm acreage and convention methods of coverage calculations. These lengths also complement lengths of other products used in fields including drip-tape coils. In addition these lengths minimize the changing of rolls to reduce labor cost for handling shorter rolls. The roll can be configured to work on layer equipment manufactured by Kenco, Rainflo and JGB and on home made layers with similar specifications. These pieces of equipment generally use 48 inch, 52 inch and 60 inch widths. Therefore the width of the rolls of degradable mulch film can come in these width as well as any other widths that might be demanded by the growers or that is found useful. There is usually a three (3) inch core at the center of the roll, and the diameter and weight of the rolls must be compatible with the capacity of the equipment. However the width of the core can be altered or modified so that it might work on a large variety of layer equipment.
The mulch roll has a special manufacturing process that the roll is configured with the middle portion of the width of the roll is made of an above ground degradable film A,
For shipping the roll of mulch film has an outer wrap around the product to maximize storage life of the product and to protect the outer portion of the roll and prevent pre-mature degradation. For best results in using the mulch film it is important to keep the roll in the outer wrap and store it in a cool, dry area, out of sunlight until application of the mulch roll. Care should be taken with the roll to prevent denting. Once the wrap is opened the laying of the roll and planting through the above ground degradable film should be performed within a limited time. When applying the mulch film roll it is important to use the clutch properly on the tractor to avoid undue stress on the mulch film. Choose a day that is not too windy or when the soil is to wet or to dry. It is important to take care in the preparation of the bed on minimize clumps, rocks and other sharp objects which might have a adverse affect on the mulch film.
One of the things that makes this mulch film special is that both the above ground degradable film A and the below ground degradable film B are formulated to degrade coincidentally so that the anchor function continues until the above ground film no longer requires anchoring. The mulch film then degrades into the soil with no harm to the soil.
The degrading of the mulch film provides several benefits to the growers, first it protects the environment by eliminating massive quantities of plastic that would otherwise lay in disposal sites for extended periods of times and second, the cost for pick up and disposal of an ordinary plastic film is eliminated.
The stages of the above ground degradable film A are that: first, there is transition period, second is the on-set of degradation and physical property loss, third there is embrittlement, fourth there is fragmentation, fifth there is miniaturization and sixth the film is visually gone. At this stage the average Mn and average Mw are typically below 500 Daltons. Transition Period is a period which the product exhibits features of normal plastic. This may be different for different crops but in one case it might be for about 100 days after application. Next is the onset of embrittlement, which commences at the end of the transition time. Then the film goes into the embrittlement stage, which can very in length but in one embodiment it might be 30 to 60 days. The film then goes into fragmentation. Fragmentation is marked by substantially all of the plastic having fragmented into brittle pieces with dimensions between several feet to several inches or smaller. During fragmentation the film loses elastic characteristics and changes crystallinity so that there is no sticking or adhering of the film fragments to the farming equipment when the field is plowed, disked, roto-tilled, or in other ways worked. Miniaturization then occurs at the end of the fragmentation stage when the mechanical action of plowing, tilling or discing adds to the breakdown of the embrittled film. At this stage all pieces of the film further fragment into miniature pieces between one inch and confetti sized pieces or smaller. Then after one or two years in the soil all the pieces are visually gone.
The above ground degradable film A
In one of the embodiments of the invention a mulch film 28,
In another embodiment of the invention addition elements and compounds can be added to the plastic or natural resin, which would help nourish the soil once the film starts to decompose. Examples of these additives include the three primary macronutrients: nitrogen, phosphorous and potassium, as well as the three secondary macronutrients: calcium, sulfur and magnesium. In addition trace elements or micronutrients such as copper, iron, boron, chlorine, manganese, zinc, selenium and molybdenum. Ammonium based compounds such as anhydrous ammonium nitrate, ammonium phosphates and urea. One example of a compound that could be added is potash, which is a combination of potassium with chlorine. By adding combinations of these elements and compounds to the resin matrix the soil would be enriched by the decomposition of this mulch films.
In another embodiment of the invention addition compounds can be added to the plastic or natural resin, which would give the mulch film a natural repellant to insects and pest through the addition of an essential oil. These essential oils are volatile materials, which occur in certain plants and are recovered by an accepted procedure such that the nature and composition of the product is nearly as practicable and unchanged by such procedures. These oils have been extracted from 3000 plants of which 200 to 300 are commonly traded on the world markets. Essential oils or plant extracts are the compounds found in the leaves, stems and reproductive structures of the plant. Essential oils are aromatic volatile liquids distilled from shrubs, flowers, trees, roots, bushes and seeds. None are synthetic or hydrogenated but are highly oxygenated species of complex compositions. Essential oils are different from vegetable oils such as corn oil, peanut oil and olive oil. They are not greasy and do not clog the pores like many vegetable oils in the human arteries. An essential oil is an aromatic, volatile substance extracted by distillation or physical expression from a single botanical species. The resulting oil should have nothing added or removed. Examples of these essential oils include, but are not limited to cedarwood oil, neem oil, citronella oil, wintergreen oil, oil of wintergreen (methyl salicylate), eucalyptus oil, tea tree oil and combinations thereof. It should be noted that some of these oils may have more than one verity for example cedarwood oil comes as cedarwood oil cedrus atlantica, cedarwood oil cedrus deodara, cedarwood oil Chinese cupressus funebris franco, cedarwood oil Texas juniperus ashei Buchholz, cedarwood oil juniper juniperus recurva Buch-ham ex D. Don, cedarwood oil Virginian Juniperius Virginiana L. In addition Eucalyptus oil can be broken down into eucalyptus globules, citronelle eucalyptus citriodora, eucalyptus camaldulensis.
It should be noted that methyl salicylate, oil of wintergreen in the past was a natural product commonly distilled from the twigs of Sweet Birch and Eastern Teaberry. Today it is possible to synthesize methyl salicylate by esterifying salicylic acid with methanol.
The mulch film is comprised of two different films, which are bonded or brought together in two different ways either using co-extrusion technology or a unique laminator like structure. This mulch film brings the these two different types of films A and B together so that the film appears, feels and act as one film. The mulch film has no bump or change in diameter where the two types of film abut or adjoin. To produce this unique mulch film one can use from 2 to 6 extruders. This process also blends well to preserve the film technology using 2 to 6 extruders. The two or three film resins structures can be extruded into thin films by the cast-die process and joined together as the thin film exits the die.
By varying the composition of components 2, 3, 4, and 5, we can achieve various degrees of degradation under the soil.
