Abstract:
A netless straw mat or blanket for grass seed and other such applications is formed by applying an adhesive to a layer of straw. The layer of straw is compressed and formed into a roll for distribution and use at an installation site.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 61/779,526 filed on Mar. 13, 2013, entitled, MESHLESS BLANKET FOR GRASS SEED, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Various types of erosion control blankets or mats have been developed. In use, blankets of this type are placed on the ground following excavation or the like to prevent erosion, retain moisture, and to protect the seeds from being blown away due to wind or weather. The blankets also prevent or reduce consumption of grass seeds by birds or other animals. 
     Known erosion control blankets may be made from straw or other material that is held together by a mesh including polymer net and polymer thread. The polymer net does not readily degrade, and the net may therefore remain for some time after the grass has begun to grow. The net tends to become entangled in lawn mowers, and may also pose a hazard for wildlife. 
     SUMMARY OF THE INVENTION 
     One aspect of the present invention is the method of making netless/meshless mat for erosion control of soil that has been seeded for grass or the like. The method includes providing plant material comprising stalks of plants. The plant material may comprise straw or other suitable substantially dry material. The plant material is formed in a layer, an adhesive is applied to the layer of plant material. The layer of plant material may be formed on a moving conveyor, and the adhesive may be sprayed onto the mat utilizing a spray head positioned above the conveyor. After the adhesive is applied one or more fans may be utilized to provide forced air drying of the adhesive. The layer of material is compressed (before or after drying the material utilizing forced air) utilizing a pair of rollers or a pressing plate. The mat may be formed into a roll, or it may cut into individual sheets and stacked. The mat may be placed onto a soil surface that has been seeded with grass or other seeds to prevent erosion and to protect the grass seeds from birds and other animals. The blanket does not require polymer mesh or other reinforcements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The FIGURE is a partially schematic isometric view of a device utilized to make an erosion control blanket according to one aspect of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the FIGURE, a device  1  may be utilized to produce an erosion control blanket  10  according to one aspect of the present invention. According to one aspect of the present invention, bales of straw  9  are fed into a separator or chopper  4  that breaks up the bales of straw  9  and blows loose straw through a conduit  7  to a hopper  5 . Straw from hopper  5  is distributed onto a first conveyor  8  by a tamber wheel  6  to create a relatively uniform layer  12  of straw  2  on first conveyor  8 . The chopper  4 , hopper  5 , and tamber wheel  6  may comprise known components previously utilized in the art in connection with production of straw blankets of the type having a mesh reinforcement. Although separator  4  is referred to as a “chopper”, it will be understood that the primary function of the separator or chopper  4  is to break up the bales of straw  9 , and the individual stalks of straw are preferably not cut or broken such that the stalks remain as long as possible. Conveyor  8  moves the layer of straw  12  under an applicator  18  of an adhesive-applying device  16 . Adhesive-applying device  16  may comprise a reservoir/pump unit  22 , and a conduit  24  that supplies adhesive to the applicator  18 . Applicator  18  may comprise a spray head that sprays adhesive  20  onto layer  12  of straw  2 . The adhesive  20  may comprise a hot melt adhesive, and the glue-applying device  16  may include a heating element or unit (not shown) that heats/melts the adhesive  20  prior to application by applicator  18 . Alternatively, as discussed below, applicator  18  may comprise a sprayer that applies a biodegradable ethylene vinyl acetate adhesive that may be dried using forced air  38  of fan unit  36 . In the illustrated example, applicator  18  comprises an elongated spray head that distributes the adhesive  20  onto the layer  12  of straw. However, the glue may be applied utilizing a plurality of individual spray heads or other suitable device. 
     After the adhesive  20  is applied, the layer  12  of straw  2  passes between first and second rollers  26  and  28 . The rollers  26  and  28  compress the layer  12  to form a mat or blanket  30 . The layer  12  of straw may be compressed utilizing devices other than rollers  26  and  28 . For example, a reciprocating press plate (not shown) may be utilized to compress the layer  12 . After being compressed, the mat or blanket  30  is then transported on an optional second conveyor  32  and wound onto a roll  34 . The blanket  30  may have a width “W” of about 4′, and may be cut into pieces having a length of, for example, 25′ such that roll  34  comprises a 4′×25′ piece of mat or blanket  30 . 
     The adhesive  20  may comprise a HM067 hot melt adhesive available from Southern Chemical Formulators, Inc. This adhesive is preferably applied at a rate of about four pounds for each 4′×25′ blanket, or about 0.04 pounds per square foot. This provides a mat or blanket  30  having significant strength. 
     Alternatively, adhesive  20  may comprise an ethylene vinyl acetate co-polymer such as LD Davis APX 1039 available from LD Davis Industries of Jenkintown, Pa. This adhesive is biodegradable, and provides sufficient strength and flexibility to permit the blanket to be wound into rolls for transportation and storage. Other suitable adhesives include LD Davis AP 601, APX 1038, APX 1040, and PY 10 adhesives. The adhesive may be applied utilizing an automated process as described above, or the adhesive  20  may be applied utilizing a manual process. For example, a manual process according to one aspect of the present invention includes combining 11.65 ounces of the APX 1039 adhesive with 3.3 ounces of water in a Wagner Flexio 570HVLP spray gun container. Chopped straw having a length of about 3 inches to about 7 inches is placed on a surface of about 20 inches by about 48 inches, and the adhesive  20  is sprayed at a distance of about 6 inches to about 12 inches onto the surface of the straw. The straw blanket is then forced air dried utilizing a fan, and cut into individual mats of about 20 inches by about 48 inches and stacked. The forced air drying process (manual and automated) preferably utilizes air that is at or below room temperature. Sheets of polymer film (not shown) may be positioned between the individual sheets of straw, and the straw blankets are preferably stacked in 15 sheets to form the equivalent of one bale that is equivalent to a 4′×25′ commercial blanket. Alternatively, a 4′×25′ blanket may be sprayed, forced air dried and rolled to form a single roll of material. 
     Referring again to the drawing, if the device  1  is utilized in connection with an ethylene vinyl adhesive, a fan unit  36  is positioned over the conveyor  8 , or optionally over the second conveyor  32 . The fan  36  blows air  38  onto the layer  12  of straw after spraying the ethylene vinyl acetate adhesive onto the straw utilizing applicator  18  of adhesive-applying device  16 . The air  38  is preferably at room temperature or below room temperature. It will be understood that the device  16  and/or applicator  18  may include a suitable reservoir/pump unit  22  and conduit  24  as required for a particular adhesive composition. The straw may be formed into a roll  34  as discussed above. Alternatively, an elongated blade  40  may be utilized to cut the blanket  10  into individual pieces that may be stacked as described above. 
     In general, the blanket  30  has sufficient strength and flexibility to permit rolling of the blanket into a roll  34 , and to permit subsequent handling and application of the blanket. Blanket  30  preferably has a strength of at least about 5.0 lbs. per linear foot of the material. Although the adhesive  20  preferably comprises an ethylene vinyl acetate adhesive, other adhesives may also be utilized according to the present invention.