Patent Publication Number: US-2020277132-A1

Title: Biodegradable Tea and Coffee Wrapper and Tag

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. provisional application No. 62/813,094 filed Mar. 3, 2019, the disclosure of which is hereby incorporated herein by reference. 
    
    
     FIELD OF USE 
     The present disclosure relates to a biodegradable beverage wrapper and tag, and more particularly to the manufacture of a tea coffee bag tag and related wrappers that is non-GMO and fully compostable. 
     BACKGROUND OF THE INVENTION 
     With the proliferation of biodegradable and recycled materials, there is a need for a substrate, particularly for tea and coffee wrappers and tags, which provides for 100% bio-degradable and does not contain any inert or non-biodegradable components. 
     The tea hag was invented by accident more than 1.00 years ago by an American merchant Thomas Sullivan, who decided to send samples of tea to customers in small silk pouches. Some people were confused—assuming that the bags were supposed to be dunked in hot water just like traditional metal tea infusers. When Sullivan heard what they were doing, he spotted a gap in the market. Thus, serendipitously, the tea bag was born. 
     At first, there were complaints that the mesh of the bags was too fine, so he replaced the silk with gauze. And as tea bags entered mass production, cheaper paper was used instead. Tea drinkers were reluctant to abandon loose leaf tea, but by the 1950s, when families were embracing new labor-saving gadgets like never before, tea bags took off. 
     Bill Gorman, of the UK Tea Council, credits the tea bag with saving the tea industry. “We would not be drinking the volume of tea we do now without them,’ he says—and he would know. “The UK is the second-largest tea market per person in the world. Ireland is first. Without tea bags, the industry would be on its knees.” 
     Major brands such as PG Tips and Tetley no longer use wood pulp to make their paper, but a vegetable fibre derived from the abaca plant—a relative of the banana grown mostly in Indonesia and South America. However, according to the Tea Council, tea companies certainly use a lot of it —, around 96 percent of the tea made is with tea bags. 
     It adds up to a lot of paper, particularly when so many tea bags are no longer rectangular—the least wasteful design for a tea hag—but round or pyramid-shaped. A PG Tips pyramid bag, for instance, is made from a rectangle of perforated filter paper approximately 70 cm square. A traditional square tea bag, on the other hand, uses around 50 cm square of paper. 
     It is estimated that tea drinkers in Britain alone throw out 370,000 tons of tea bags and tea leaves each year, along with vegetable peelings, onion skins and coffee grinds. Most of this ends up in landfill sites. The environmental impact of tea bags could easily he reduced if people simply threw the bags on the compost heap or flower beds. But it&#39;s not that simple. For while most of a tea bag is made from biodegradable paper, around 2.0 to 30 percent is not made of biodegradable material. 
     In order to stop tea bags bursting open in transit or in the cup, many are sealed with a strip of heat-resistant polypropylene plastic. That plastic doesn&#39;t compost, even after a few years, and gardeners often find these small plastic meshes amid their homemade compost (along with those non-biodegradable stickers that are found on fresh fruit such as apples). In addition wrappers and tags of the tea don&#39;t readily biodegrade. 
     There have been attempts to solve this issue that has been met with limited success. U.S. Pat. No. 8,828,895 describes a method of making filter fabrics by utilizing mono-component, mono-constituent fibers made from both high and low melt temperature Polylactic Acid (PLA) fibers. U.S. Pat. No. 9,998,205 describes the use of mono-component PLA fibers combined with PLA powders also have the ability to remove chlorine from drinking water. Both patents describe string made from mono-component, mono-constituent PLA fibers. 
     But, there appear to be no tags or wrappers that are non-GMO and biodegradable in normal composting, and made from a renewable resource. Most wrappers are made from plastic film or foils that are made plastics or metals. 
     Thus, there remains a need in the art for a process and material for coffee and tea wrappers and tags to completely biodegrade. 
     SUMMARY 
     Compared to the above methods the present disclosure fulfills the above criteria and provides additional benefits that state of the art systems cannot provide. 
     The current apparatus and method provides for a polylactic acid (PLA) that is a polymer that acts very much like polyester (PET) but is biodegradable thermoplastic aliphatic polyester and is made from renewable resources, such as corn starch, beets, and sugar cane. Most producers use Genetically Modified Organism (GMO) in the crops such as corn, beets, and the like as the feed stock for PLA. 
     Total-Corbion uses sugar cane from Thailand that is required to be non-GMO. The sugar cane is converted into sugar that can be fermented to form PLA. PLA can be produced in both a L or D configuration. The L form has a higher melt point. By combining the D &amp; L forms during polymerization, the melting point can be lowered and controlled at a specified melt temperature. 
     Polymerization of a racemic mixture of L- and D-lactides usually leads to the synthesis of poly-DL-lactide (PDLLA), which is amorphous. Use of stereospecific catalysts can lead to heterotactic PLA which has been found to show crystallinity. The degree of crystallinity, and hence many important properties, is largely controlled by the ratio of D to L enantiomers used, and to a lesser extent on the type of catalyst used. Apart from lactic acid and lactide, lactic acid O-carboxyanhydride (“lac-OCA”), a five-membered cyclic compound has been used academically as well. This compound is more reactive than lactide, because its polymerization is driven by the loss of one equivalent of carbon dioxide per equivalent of lactic acid. 
     Due to the chiral nature of lactic acid, several distinct forms of polylactide exist: poly-L-lactide (PLLA) is the product resulting from polymerization of L,L-lactide (also known as L-lactide). 
     It is well know that PLA polymers range from amorphous glassy polymer to semi-crystalline and highly crystalline polymer with a known glass transition 60-65° C., a melting temperature 130-180° C., and a tensile modulus 2.7-16 GPa. Heat-resistant PLA can withstand temperatures of 110° C. The basic known mechanical properties of PLA are between those of polystyrene and PET. It is also known that the melting temperature of PLLA can be increased by 40-50° C. and its heat deflection temperature can be increased from approximately 60° C. to up to 190° C. by physically blending the polymer with PDLA (poly-D-lactide). PDLA and PLLA form a highly regular stereocomplex with increased crystallinity. The temperature stability is maximized when a 1:1 blend is used, but even at lower concentrations of 3-10% of PDLA, there is still a substantial improvement. In the later case, PDLA acts as a nucleating agent, thereby increasing the crystallization rate. Biodegradation of PDLA is slower than for PLA due to the higher crystallinity of PDLA. The flexural modulus of PLA is higher than polystyrene and PLA has good heat sealability. 
     In one aspect, a non-woven fabric composition web of mono-component, mono-constituent PLA fiber composition consisting of: a mono-component, mono-constituent polylactic acid (PLA) fiber. The polylactic acid (PLA) fiber has different deniers and blend percentages of high and low melt fibers. The fibers, in one embodiment, have a melt flow temperature in a range of 145-175° C. and 105-165° C., for high melt flow fibers and low melt flow fibers respectively. 
     Any combination and/or permutation of the embodiments is envisioned. Other objects and features will become apparent from the following detailed description considered in conjunction with the accompanying drawings. 
     It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. 
       To assist those of skill in the art in making and using the disclosed composition and method, reference is made to the accompanying figures, wherein: 
         FIG. 1  shows a photomicrograph of the material used for a beverage tag and wrapper in accordance with one embodiment of the present disclosure; 
         FIGS. 2A-2B  illustrate the front and back, respectively, of one embodiment of a wrapper, and illustrating that color design may be utilized. 
     
    
    
     DETAILED DESCRIPTION 
     U.S. Pat. No. 8,828,895 describes methods to select a percentage of high temperature PLA blended with a low temperature PLA. The present invention is unlike bi-component fibers that have a specific percentage of high temperature polymer in a core and percentage of low temperature polymer on a sheath. This arrangement limits the ability to provide an intimate blend of fibers that can be adjusted for specific physical properties. 
     By using mono-component, mono-constituent fibers, the diameter, length, fiber shape, and melt temperature can be adjusted to achieve that desired properties. The low melt fiber melts completely and flows and adheres to the high melt fibers as shown in for example in  FIG. 1 . As shown, reference number  101  shows a PLA or Co-PLA fiber with a low melting point at about 130 C. In this embodiment, the fiber is shown after calendaring. Reference number  102  shows a PLA fiber in the same composition with a high melting point at about 175 C. Note that these different melting points are not a core fiber and a surrounding sheath fiber as previously known in the art. 
     While the US patent U.S. Pat. No. 8,828,895 provided for media up to 55 grams/square meter (gsm), tags and wrapping require heavier weights to obtain the strength and stiffness required. Thus this patent is not useful for tags or wrappers. 
     It was found in the present invention that by regulating the percentage of low melt fibers and processing conditions, the various properties of thickness, porosity, tensile strength and elongation can be controlled. 
     The following Examples further describe this material and process. The below examples are given merely to show how the invention may be implemented and in no way limits the invention to any particular embodiment. 
     Example 1 
     Initial production was produced with the following blend: 
     85% PS2438 1.5d×2.0″ High Melt—170-175° C. Melt Point 
     15% PS 2971 2.5d×1.5″ Low Melt—130° C. Melt point 
     The production line had 3 carding machines 2.5 m wide equipped with randomizer rolls to orient the fiber approximately 2:1 machine direction: cross-machine direction. 
     The webs were deposited on a continuous apron and the web was fed into a two-roll calendar heated at 140 C producing a nonwoven fabric in widths up to 2.5 meter wide. Other lines are capable of producing up to 5.5 m wide. 
     The product was produced at 40 gsm. While, this was acceptable for coffee or dusty product pouches, it did not have adequate strength and porosity needed for tags or wrapping. 
     Example 2 
     The next production run utilized a shorter Low melt fiber with the hope of achieving better dispersion. 
     85% PS2438 1.5d×2.0″ High Melt—170-175° C. Melt Point 
     15% PS 2971 2.5d×1.0″ Low Melt—130° C. Melt point 
     The product was run on the same production line at 40 gsm. The result was far better dispersion of the low melt fiber, but a marginal improvement of physical properties. 
     Example 3 
     At this point, a change of fiber manufacturing line was chosen to make more uniform fibers with less shrinkage to improve web quality and faster production rates. 
     The fiber blend was also changed to achieve a stronger and stiffer web. The new blend was: 
     80% NwN Type 490 1.7 dTex (1.5 denier) PLA×50 mm (2″) (Melt point 170° C.) 
     20% NwN Type 460 2.5 dTex (2.25 denier) PLA×38 mm (1.5″) (Melt point 135° C.) 
     The product was run at 40 gsm, but the strength increased by 80% and the stiffness was much improved. 
     Example 4 
     The next production run was established at an increased weight of 60 gsm and an increased binder level: 
     77% NwN Type 490 1.7 dTex (1.5 denier) PLA×50 mm (2″) (Melt point 170° C.) 
     23% NwN Type 460 2.5 dTex (2.25 denier) PLA×38 mm (1.5″) (Melt point 135° C.) 
     The result was a very strong product at 60 gsm that was suitable for printing and slitting for tags and wrappers. 
     The product was slit at 255 gsm and was printed at an established label company. Logos were developed and printed on the 60 gsm product as shown in  FIG. 2A  and  FIG. 2B . Also illustrated in  FIGS. 2A-B  is the ability for the biodegradable material to be printed in color. Biodegradable inks may be utilized to further the biodegradability of the wrappers and tags. Printability on the biodegradable formulation was shown to hold fine detail and color images unlike other biodegradable mixtures in the past. 
     In one aspect, when the tags are made of the same components as the filter media and string described in U.S. Pat. No. 8,828,895, all three products (filter, string, and tag) can be attached to each other using ultra-sonic sealing at very high speeds. 
     It was determined that a fabric with a weight greater than 50 gsm was superior for stiffness, tensile strength, and opacity. The best weight range is from 55 to 120 gsm. 
     The wrapper material is 60 gsm and can be printed with normal printing equipment and slit to the desired width. It seals easily with both controlled heated platens or with ultrasonics. 
     Trials were performed on a pilot basis to increase the percentage of low melt, mono-component, mono-constituent fibers. The result was increased stiffness, increased strength and less opacity. This appears to be helpful to improve the clarity of the tea and coffee bags. 
     Fibers that are finer denier such as 0.6 to 1.4 denier will allow for greater opacity and better coverage, but may sacrifice strength. Fibers that are coarser such as 3 to 6 denier may be stronger but may result is more holes and less coverage. 
     Further, increasing the binder content appears to decrease the airflow and may allow the production of wrapping material with controlled airflow to prevent the intrusion of undesirable materials such as mold, mildew, fungus or bacteria through the wrapping into the material inside the wrapping. 
     Further, this increased binder level can be adjusted to allow moisture to escape from the material inside the wrapper. 
     Depending on the embodiment, the wrapper may be used for meat, vegetables, fish, candy, cheese, or any foodstuff where controlled breathability, printability, and rapid biodegradability are desirable. 
     The tag and wrapper go completely clear when wet allowing the material inside to be seen clearly. Since the wrapper can be sealed with heat or ultrasonics, this eliminates the need for sealing tape. 
     Additionally, Titanium Dioxide may be added to the fibers to increase opacity. Other pigments such as Phthalo Blue, Phthalo green, yellow ochre, iron oxide, or other color fast pigments may be used to have colors that are water fast and withstand fading in sunlight. 
     The printing could use vegetable dyes or the fabric could be fully colored with vegetable dyes to remain organic and completely compostable. 
     Finally, an impermeable film of PLA or other plastic such as PE, PP, PET, or polyamide can be laminated to the wrapping to prevent airflow in either direction of the wrapping material. 
     The following aspects were found possible utilizing the teachings of the invention. A non-woven fabric composition web for a tea or a coffee wrapper and tag consists of a tea or a coffee wrapper and tag having a plurality of mono-component, mono-constituent polylactic acid (PLA) fibers and a pigment. The polylactic acid (PLA) fibers as described herein have different deniers and a blend percentages of a high melt PLA fiber and a low melt PLA fibers with a melt flow temperature in a range of 145-175° C. and 105-165° C., respectively. Again, the tea or the coffee wrapper and tag are non-GMO and fully compostable in about 30 days. In one aspect, the fibers have a weight range from 55 gsm to 150 gsm. In another aspect, the fibers have a weight range from 55 to 75 gsm. The fibers have a percentage of a high melt fiber ranging from 55% to 95% and a percentage of a low-melt fiber ranging from 5% to 45%. Depending on the embodiment, the fibers may also have a denier ranging from 0.7 to 6.0 denier. The fibers may also have a length that ranges from 12 mm to 130 mm Fiber denier ranges from 1.5 to 2.5 denier as also achievable using the principles of the present invention. The fibers may also have a length that ranges from 25 mm to 51 mm Depending on the embodiment, the pigment used with the fibers is a titanium dioxide pigment for making the non-woven fabric composition opaque in color. The pigment may also be a color fast pigment selected from a group consisting of Phthalo Blue, Phthalo Green, iron oxide, Yellow Ochre, and any combination thereof. Depending on the embodiment, the pigment is added to either the low melt PLA fiber, the high melt PLA fiber, or both the low and the high melt PLA fibers to provide a colored fabric. The tea or the coffee wrapper and tag are printable with text, drawings, or logos in biodegradable colored ink or other ink that bio grades well. The wettability for the material used for the tea and coffee wrappers and tags is sufficient so that fine designs on the wrapper and tag do not bleed off and keep their detailed form and color. The composition for the tea or the coffee wrapper and tag may also be used for wrapping meat, vegetables, fish, candy, cheese, or foodstuff to provide controlled breathability and rapid biodegradability. 
     Any headings and sub-headings utilized in this description are not meant to limit the embodiments described thereunder. Features of various embodiments described herein may be utilized with other embodiments even if not described under a specific heading for that embodiment. 
     Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. 
     While exemplary embodiments have been described herein, it is expressly noted that these embodiments should not be construed as limiting, but rather that additions and modifications to what is expressly described herein also are included within the scope of the invention. Moreover, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations are not made express herein, without departing from the spirit and scope of the invention.