FIELD OF INVENTION

[0001] The present invention relates to a biodegradable drinking straw made from com husk. The present invention also relates to a method of treatment of the com husk for preparing the biodegradable drinking straw.

BACKGROUND OF THE INVENTION

[0002] Single use plastic straws are the most commonly used drinking straws world over. However, they are non-biodegradable, and therefore has emerged as the major plastic pollutant in environment including marine eco systems, and cause damage to wildlife and humans. Many countries regions, and municipalities have banned single-use plastic straws to reduce plastic pollution. The plastic used in plastic straws become microplastics and enter the food chain and cause many ailments in humans and animals.

[0003] Biodegradable single use straws such as paper straw are already marketed with the intent to replace single use plastic straws. However, paper straws are not an ideal replacement for plastic straws because, paper straws become soggy and disintegrate in cold and hot beverages which is inconvenient to the user. Also, plastic straws have an equally negative carbon foot print, thereby burdening the environment.

[0004] Other biodegradable ecofriendly straws include bamboo straws and metal straws. Bamboo straws and metal straws are reusable straws, and is not practical for being used as single use straws. Further, these straws are not economical for single use because it is not cost effective when compared to plastic straws. Metals straws may cause allergic reaction in users and is not a good option to use with hot beverages as it can cause lip bum.

[0005] The present invention relates to a drinking straw which is viable as a single use straw, is cost effective and is biodegradable. The drinking straw as per the invention does not become soggy when placed inside hot or cold liquid and do not cause allergy or burnt lips. The drinking straw as per the present invention is made from com husk.

[0006] Com husks are the outer covering of an ear of com. Com husks are naturally bio-degradable, fibrous and weather resistant material which has proved to be ideal for protection of com cobs from rain, sunlight and insects. The naturally sun-dried com husks stored well has a shelf life of 6 to 12 months. Com husk is a natural waste product which are produced in abundance and is available all throughout a year and does not have a widely known industrial or domestic use. Com husks has the distinctive advantage of moderate strength, toughness and high elongation with high durability. Use of com husk for making straws has the potential to monetize this waste product into a commercially viable raw material. It can also provide extra income to the farmers and has the potential to provide consumers with an ecofriendly replacement for plastic straws. Com husks being a natural waste, will provide an economically viable option for use as a single use straw. Using com husk for making drinking straw has the potential to reduce agricultural waste and preventing burning of the waste material which cause air pollution. The production volume of com in India in the year 2020-21 was 32 million metric tons and in the year 2021-22 is 30 million metric tons. There are no large scale commercial or industrial use available for com husk.

[0007] Therefore, a need exists for replacing single use plastic straws with single use biodegradable straw option, which is also economical. The present invention addresses this need by providing a single use biodegradable com husk straw.

[0008] The present invention also provides a method of treating the raw com husk before it can be made to a straw.

OBJECT OF THE INVENTION

[0009] The object of the present invention is to provide a drinking straw which is biodegradable, for use as a single use straw. It does not become soggy when placed inside hot or cold liquid. The single use biodegradable straw as per the present invention is made from com husk.

[0010] Another object of the present invention is to provide a method for making a biodegradable straw from com husk.

[0011] Yet another obj ective of the invention is to provide a method of treating the com husk before rolling into straw.

[0012] Another objective of the invention is to provide a method for rolling the biodegradable straw.

SUMMARY OF THE INVENTION

[0013] The present invention comprises a biodegradable drinking straw made from com husk. The com husk is cut into rectangular strips. The straw is made of two layers, a first layer made from a strip which is spirally rolled, and a second layer made from another strip which is horizontally rolled. The two layers are bond together with an adhesive. The drinking straw has a diameter of about 6 mm to 12 mm.

[0014] The present invention also comprises a method of making the drinking straw from com husk. The com husk is chemically treated with potassium hydroxide to make the rectangular strips sturdier and rigid. The treatment also provides deterrence against fungus, molds and bacteria.

[0015] Specific embodiments of the invention are as below.

[0016] Embodiment A relates to a method of treating com husk for use as a drinking straw, method comprising steps of; clean the com husk using water to remove dirt and impurities, cutting the cleaned husk in to rectangular stripes, immerse the cut stripes in 5% potassium hydroxide for about 10-30 minutes, wash the KOH treated com husk stripes to remove impurities, dry the com husk stripes at about 40-50°C, roll the dried com husk stripes in to the form of a drinking straw,

[0017] Embodiment B relates to the method as defined in previous embodiment, wherein the com husk is cut in to rectangular stripes based on the curvature of whole com husk sheath.

[0018] Embodiment C relates to the method as defined in previous embodiment, wherein a single drinking straw comprises two layers of treated com husk stripes.

[0019] Embodiment D relates to the method as defined in previous embodiment, wherein the process of rolling treated com husk in to drinking straw comprises steps of; spirally rolling a first layer of treated com husk along an axis of a rod, a second layer is horizontally rolled over the first layer along axis of the rod, applying an adhesive between the first layer and the second layer, the rolled layers are allowed to dry and bond together, the dried rolls are baked in an over at about 100 to 150°C.

[0020] Embodiment E relates to the method as defined in previous embodiment, wherein after baking the straws, a thin coating of wax is applied on the straw.

[0021] Embodiment F relates to the method as defined in previous embodiment, wherein the coating of wax is applied inside a dehumidifying chamber. [0022] Embodiment G relates to the drinking straw as per the method defines in previous embodiments.

[0023] Embodiment H relates to the drinking straw as defined in previous embodiment, wherein the diameter of the rod is from 6mm to 12mm.

[0024] The specific embodiments are discussed in detail below.

BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1. Fig 1 illustrates the first layer spiral rolling of the straw.

[0026] Figure 2. Fig 2. Illustrates the second layer horizontal roll which is carried out over the first spiral roll.

DETAILED DESCTRIPTION OF THE INVENTION

[0027] The present invention will now be described more fully herein after. For the purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Thus, before describing the present invention in detail, it is to be understood that this invention is not limited to particularly exemplified systems or embodiments that may of course, vary. The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only, and in no way limits the scope and meaning of the invention or of any exemplified term. Likewise, the invention is not limited to various embodiments given in this specification.

[0028] As used herein, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise. The term "and/or" means one or all of the listed elements or a combination of any two or more of the listed elements. [0029] The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.

[0030] When the term “about” is used in describing a value or an endpoint of a range, the disclosure should be understood to include both the specific value and endpoint referred to.

[0031] As used herein the terms “comprises”, “comprising”, “includes”, “including”, “containing”, “characterized by”, “having” or any other variation thereof, are intended to cover a non-exclusive inclusion.

[0032] The present invention comprises a biodegradable drinking straw made from com husk. The com husk is cut in to rectangular strips and treated with potassium hydroxide. The treated strips are used to make the drinking straw which is the final product.

[0033] The com husk used in the present invention was procured from local vegetable market in Cochin, Kerala.

[0034] The straw is made of two layers, a first layer made from a strip which is spirally rolled (10) (Figure 1) and a second layer made from another strip which is horizontally rolled (Figure 2, 30). The two layers are bonded together with an adhesive (20) to make a rod shape. The rod has a diameter from 6 mm to 12 mm and a length of about 8 cm to 15 cm.

[0035] The present invention also comprises a method of making the drinking straw from com husk. The com husk is chemically treated with potassium hydroxide to make the rectangular strips sturdier and rigid. The treatment also provides deterrence against fungus, molds and bacteria.

[0036] The com husks are washed in water to remove any dirt and impurities on the surface of the husk. The cleaned husk is cut in to rectangle shaped strips. The strips are cut in to rectangle shapes based on the curvature of whole com husk sheath.

Chemical treatment of Corn husks

[0037] The cut strips are immersed in 5% potassium hydroxide (KOH) solution; preferably food grade KOH, for about 10 to 30 minutes. Preferably the cut strips are immersed in 5% KOH solution for about 20 minutes. A slimy layer is usually formed during the KOH treatment. After 20 min the com husk strips are rinsed with water till the KOH residue and the slimy layer formed on the husk strips are removed or washed off. The above treated com husk strips are dried at a temperature of about 40 to 50 degrees Celsius.

[0038] The com husk become sturdier, rigid and thin after the chemical treatment. The chemical treatment prevents formation of fungus and molds on the strip and also has antibacterial effect. This increases the shelf life of the com husk straws.

Rolling of the strips to a drinking straw

[0039] Two rectangular strips are used to make one com husk straw. Com husk straw is made of two layers made from two rectangular strips. The first layer is spirally rolled along the axis of a rod and the second layer is horizontally rolled on to the spirally rolled layer, to cover the spirally rolled layer.

[0040] The edges of the spirally rolled layer may be applied with an adhesive to hold the spiral coil. Adhesive is also applied in between the two layers to bond the two layers together to make a single drinking straw. The straw is then allowed to dry and bond together to make the finished product. The dried straw rolls are baked in an oven at about 100 to 150°C.

[0041] Once the rolls/straws are baked a coating of wax is applied on the rolls inside a dehumidifying chamber in the absence of moisture.

[0042] The structural strength and rigidity of the treated straw improves the quality of the finished product. The chemically treated straw shows negligible or no moisture absorption. This prevents the straw from becoming soggy when immersed in a hot or cold beverage.

[0043] Examples

[0044] Example 1 : Migration test

[0045] Migration testing is usually performed on polymeric products that are in contact with food to determine whether chemical substances are transferred from packaging and food contact material to food. The transfer of chemicals from food contact materials to food is called migration. The passing substances are called migrants. The migration test was conducted as per BIS test method IS 9845: 1998. (RA 2020).

Experimental method: (Please explain the method here, the reports states stimulat is n- heptane, condition @38degree C, for 30 min)

[0046] In the present invention, the no. of leachents migrating from our straw into the liquid/food it come in contact with during usage is well below permissible limits. Also, the test results prove that the amount of extractive migrating in fact slightly reduced post treatment with the proprietary chemical (KOH).

[0047] Example 2: Microbial count test [0048] For the microbiological quality and safety of a product, the number of viable microorganisms such as bacteria and fungi that a product contains is decisive. The total germ count is determined and this test is an important part of ensuring product quality. Testing is performed in accordance with pharmacopoeia regulations & standardised procedures.

* colony forming units

[0049] The experimental results indicate that the no. of fungus/bacteria/virus present in the com husk is significantly reduced by a factor of more than 9,000 times. Post treatment with KOH, the microbial count reduces to acceptable standards, which are well below permissible regulatory standards.

[0050] A higher microbial count will significantly increase health and safety concerns. Pretreatment with KOH improves the shelf life of the product.

[0051] The straw as per the present invention is a good replacement for single use plastic drinking straw. The straw as per the present invention is also a single use drinking straw, which can be disposed of after single use. Since com straws are biodegradable, the disposed straw will not pose any environmental threat, as it will decompose over time. The single use biodegradable com husk straw as per the present invention addresses the technical problems posed by plastic straws and other alternates available in the market.

[0052] While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope of the invention as claimed.