Preamble to the Description
The following specification describes the invention and the manner in which is to be performed:
DESCRIPTION OF THE INVENTION
Technical field of the invention
The present invention relates to a method to recycle and reduce plastic wastes. More particularly, the invention relates to the method to convert recycled polyolefins into hot melt adhesive films and granules.
Background of the invention
Solid waste disposal is an important problem threatening today's world. Plastic waste forms a major portion of the solid waste and is dumped into oceans and landfills. Aquatic life and ecosystems are gradually getting destroyed and many ocean species of animals are found to be getting endangered or extinct. Additionally, traces of micro-plastics have been found in ocean fish used in food preparations.
The existing technologies to manufacture thermoplastic polyolefin hot melt adhesives (HMA) utilize virgin polymers such as ethylene vinyl acetate (EVA), poly vinyl acetate (PVA), thermoplastic poly urethane (TPU), which are based on fossil fuels. As a result, natural resources are depleted and it also adds to the burden of additional carbon emissions thereby contributing to global warming. These adhesives and adhesive films are utilized for bonding various substrates such as wood-to-glass, wood-to-wood, wood-to-plastic, Laminates-to-Wood etc.
[0005] The US patent document US20070187032 Al titled "Polyolefin based hot melt adhesive having improved heat resistance'''' discloses a hot melt adhesive composition, which exhibits improved heat resistance and is used to bond multiple components made of dissimilar materials. The composition includes a blend of

5% to 50% by weight of poly alpha olefin polymer, 5% to 65% by weight of tackifier, and 5% to 70% by weight of rubbery polymer, 0 to 3% by weight of stabilizer and wax. However, the document does not mention the use of recycled plastic.
[0006] The US patent document US6329468 Bl titled "Hot melt adhesive based on semicrystalline flexible polyolefins" discloses a flexible polyolefin-based hot melt adhesive composition for bonding nonwoven disposable articles. The composition includes polyolefin polymers, tackifier resin, a plasticizer, wax and stabilizer in which the melt flow rate of the polyolefin polymer is greater than 5 g/10 minutes and density is between 0.86 to 0.90 g/cm . However, there is no reference to use of recycled plastic polymer amongst the ingredients.
[0007] The US patent document US6218457 Bl titled "Hot melt adhesive with high peel and shear strengths for nonwoven applications'" relates to a polybutylene based hot melt adhesive composition, which can withstand high peel and shear loads at elevated temperature for extended periods of time without any change in bonding property. However, the ingredients include virgin polyolefins and not recycled plastic material.
[0008] The currently available methods pertain to converting virgin plastics to hot melt adhesives. None of them involve the use of reprocessed or recycled plastic material in the manufacturing process.
[0009] Hence, there is a need for a simple, energy-saving and economical method to utilize the recycled plastic material for the manufacture of hot melt adhesives which can bring about plastic waste reduction.
Summary of the invention
[0010] The present invention relates to a method of conversion of recycled polyolefins into hot melt adhesive films and granules. The method results in reduction and replacement of virgin plastics in the manufacture of thermoplastic

polyolefin hot melt adhesives as the method utilizes polyolefin-based thermoplastic wastes to manufacture polyolefin hot melt adhesive films and granules.
[0011] The thermoplastic polyolefin plastic wastes used in the invention consists of low density poly ethylene (LDPE), linear low density poly ethylene (LLDPE), high density poly ethylene (HDPE), poly propylene (PP), biaxially oriented poly propylene (BOPP), poly ethylene terephthalate (PET), poly vinyl chloride (PVC), ethylene vinyl acetate (EVA), poly vinyl alcohol (PVA1) and poly vinyl acetate (PVAc). The thermoplastic polyolefin wastes are in sorted or unsorted form.
[0012] In the present invention, the polyolefin plastic wastes are converted into different forms such as hot melt adhesive (HMA) films, granules as well as filler-mixed composite granules by using thermoplastic extrusion process, which includes blown/cast film extrusion, twin screw extrusion and granulator processes respectively.
[0013] The method of the invention involves the steps of mixing of ingredients of the composition including 80% to 90 % of recycled plastic granules, 4%-10% of tackifier, 5%-10% of polarity inducing agent and 0.2% -0.5% of catalyst by weight of the composition, loading the ingredients of the composition into a screw barrel extrusion machine, maintaining screw barrel movement at constant speed and the temperature inside the screw barrel extrusion machine between 160°C and 185°C, melting and reacting of the ingredients of the composition inside the screw barrel extrusion machine and extruding the reacted contents from the screw barrel extrusion machine as hot melt adhesive film and granule.
[0014] The process of manufacturing is completely effluent-free and uses plastics wastes thereby reducing plastic wastes. It does not have any form of waste generation during or after the process of manufacturing. All the ingredients and raw materials used in the invention are locally procured. The HMA films,

granules and composite granules produced by the invention are used as thermoplastic binders in various applications.
Brief description of the drawings
[0015] The foregoing and other features of embodiments will become more apparent from the following detailed description of embodiments when read in conjunction with the accompanying drawings.
[0016] FIG 1 illustrates the flowchart for a method for conversion of recycled polyolefins into hot melt adhesive films and granules.
Detailed description of the invention
[0017] In order to make the matter of the invention clear and concise, the following definitions are provided for specific terms used in the following description.
[0018] The term "recycle" refers to converting to a reusable form.
[0019] The term "extrusion" refers to a manufacturing process in which a softened blank of a metal or plastic material is forced through a shaped metal piece or die.
[0020] The invention relates to a method of conversion of recycled polyolefins into hot melt adhesive films and granules. The invention replaces the use of virgin plastics and uses polyolefin-based thermoplastic wastes to manufacture polyolefin hot melt adhesive films and granules.
[0021] The method reduces carbon footprint in the manufacturing process of thermoplastic polyolefin hot melt adhesive film and granules by replacing the use

of depleting fossil fuels in virgin plastics manufacture with recycled thermoplastics.
[0022] The initial step in the invention is the recycling of plastic waste into recycled plastic granules. The sorted and/or unsorted plastic waste is washed to remove impurities such as labels and adhesives. The washed waste is loaded into different conveyer belts that run the waste through different shredders. The shredded plastic is melted and extruded to produce the recycled plastic granules.
[0023] The ingredients of the composition to prepare the hot melt adhesive films and granules include reprocessed or recycled plastic granules, tackifier, polarity inducing agents and catalyst.
[0024] The reprocessed or recycled plastic granules used are low density poly ethylene (LDPE), linear low density poly ethylene (LLDPE), high density poly ethylene (HDPE), poly propylene (PP), biaxially oriented poly propylene (BOPP), poly ethylene terephthalate (PET), poly vinyl chloride (PVC), ethylene vinyl acetate (EVA), poly vinyl alcohol (PVA1) and poly vinyl acetate (PVAc) either individually or in mixtures. The quantity of recycled plastic granules used as ingredient in extrusion is 80% to 90% by weight of the composition. The percentage is varied depending on bonding properties required for specific applications to which the hot melt adhesive is likely to be used.
[0025] The tackifier used in the composition of the invention is Poly Iso Butylene (PIB), which is in the form of granules or liquid. The tackifier acts as a 'cling' agent providing higher 'holding' properties to the hot melt adhesive film. The percentage of PIB is in the range of 4% to 10% of weight of the composition. However, the amount of tackifier used is varied based on different tackiness and film holding application requirements of the hot melt adhesive.
[0026] The polarity inducing agents used are Maleic Anhydride or Acrylic Acid. A relevant combination of both is used depending on the required end bonding

properties of the HMA produced. The polarity inducing agent gets 'co-grafted' with the base recycled plastic and provide polar properties to the HMA films. This provides superior bonding and adhesion properties to bind the substrates to be bonded. The percentage of Maleic Anhydride or Acrylic Acid used in the invention ranges from 5% to 10% of the weight of the composition. The quantity of polarity inducing agent added is varied based on the polarity and adhesion levels required in the hot melt adhesive films or granules.
[0027] The composition discloses the use of Dicumyl Peroxide (DCP), Benzoyl Peroxide or Iso Butyl Peroxide as catalyst in the process of blown film extrusion into HMA films or granules. The catalyst is used in the quantity range from 0.2% to 0.5%) of the weight of the composition. The percentage of catalyst is varied based on the level of co-grafting and polymerization required in the produced HMA films or granules.
[0028] According to the invention, the polyolefin plastic wastes are converted into hot melt adhesive films, granules as well as filler-mixed composite granules by using thermoplastic extrusion process, which includes blown or cast film extrusion, twin screw extrusion and granulator processes respectively. The invention uses a normal single screw barrel extruder in manufacturing both the adhesive blown or cast films as well as adhesive granules.
[0029] Figure 1 illustrates the steps involved in the method (100) of conversion of recycled polyolefins into hot melt adhesive films and granules. The method starts with the step (101) of the mixing the ingredients of the composition including 80% to 90% of recycled plastic granules, 4%-10% of tackifier, 5%-10% of polarity inducing agent and 0.2% - 0.5% of catalyst by weight of the composition. At step (102), ingredients of the composition are loaded into a screw barrel extrusion machine. At step (103), the screw barrel movement is maintained at constant speed and the temperature inside the screw barrel extrusion machine is maintained between 160°C and 185°C. At step (104) the ingredients of the

composition inside the screw barrel extrusion machine are melted and reacted. Finally, at step (105) the reacted contents from the screw barrel extrusion machine are extruded as hot melt adhesive film and granule.
[0030] The ingredients of the composition are mixed together and loaded into a hopper above the blown/cast film extrusion machine or granule extrusion machine. The ingredients slowly enter into a temperature-controlled screw barrel, where the temperature is maintained between 160°C and 185°C. The temperature to be maintained in the screw barrel depends on the quantity and ingredients of the composition used in the blown/cast film/granulation process, such that the product with relevant adhesive properties for specified application(s) is obtained.
[0031] As the ingredients of the composition enter the temperature-controlled screw barrel, they melt and start reacting with each other. The speed of the screw barrel movement is maintained in order to give the appropriate time for the melt-reaction process for various ratios of the ingredients in the composition as needed. At the end of the screw barrel, the reacted plastic is either extruded as hot melt adhesive film (blown/cast film) or as hot melt adhesive granule depending on type of product required.
[0032] The invention is a composition to make hot melt adhesive film and granules comprising of 80% to 90% recycled plastic granules, 4%-10% tackifier, 5%>-10%) polarity inducing agent and 0.2% -0.5% catalyst by weight of the composition.
[0033] The recycled plastic granules used in the composition of the present invention include LDPE, LLDPE, HDPE, PP, PET, PVC, EVA, PVA1 and PVAc. The recycled plastic granules in the composition are present individually or as mixture.
[0034] The tackifier used in the composition is Poly Iso Butylene and the polarity inducing agent is Maleic Anhydride, Acrylic Acid or a combination of both. The

catalyst used in the composition is either Dicumyl Peroxide or Benzoyl Peroxide or is Butyl Peroxide.
[0035] Example 1: A composition containing 90% reprocessed LDPE granules, 5% Maleic Anhydride, 4.5% Poly Iso Butylene and 0.5% Dicumyl Peroxide is mixed and loaded into a screw barrel extrusion machine. The temperature of inside the machine is maintained at 160°C and the speed of screw barrel movement is maintained at 20 rpm. The reacted contents are extruded from the screw barrel extrusion machine as hot melt adhesive film/granule.
[0036] Example 2: A composition containing 65% recycled LDPE granules, 15% recycled PET granules, 8% Maleic Anhydride, 3.5% Acrylic Acid, 8% Poly Iso Butyl ene and 0.5% Dicumyl Peroxide is mixed and loaded into a screw barrel extrusion machine. The temperature of inside the machine is maintained at 160°C and the speed of screw barrel movement is maintained at 20 rpm. The reacted contents are extruded from the screw barrel extrusion machine as hot melt adhesive film/granule.
[0037] The method of manufacture according to the invention involves maintaining the temperature well within 200°C. Hence, there is no toxic reaction or fumes related to melting of recycled plastics.
[0038] The invention relates to a method by which all recyclable thermoplastic wastes are converted into HMA films and granules. These are used as bonding adhesive films with various substrates like wood, wood veneers (plywood), decorative lamination on wood, decorative veneer lamination on wood, bonding shoe/sandal soles, bonding cardboard layers for packing materials among others.
[0039] The invention is a totally green technology as the method used plastic wastes and does not have any form of harmful waste generation during or after the process of manufacturing. The entire manufacturing process is effluent-free as it does not use water or generate waste water during or after the manufacturing process. The hot melt adhesive films or granules produced by the method of the

invention utilize up to 90% of recycled thermoplastic wastes, which is used as an ingredient. This reduces the quantity of plastic waste in the landfill and oceans.
[0040] The main advantages of the invention is that thermoplastic wastes are converted to hot melt adhesive (HMA) films and granules, bringing very high value addition to plastics recycling, and also contributing to plastics wastes reduction. Further, since sorted and unsorted plastic wastes are used for obtaining the recycled plastic granule used in the invention, the burden of sorting the plastic waste during recycling is reduced.
[0041] The method of the invention is simple, easy to operate and energy-saving. The machinery consists of simple extrusion machines and ingredients for manufacture are locally available in India. This makes the invention highly economical and cost effective. Further, the hot melt adhesives produced by the present invention have huge export potential.
[0042] While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.

Claims: We Claim:
1. A method (100) of conversion of recyclable thermoplastic, obtained from
sorted and unsorted plastic wastes, into hot melt adhesive films and
granules, the method comprising the steps of:
a. mixing one or more ingredients of a composition comprising of at
least 80% to 90% recycled plastic granules, at least 4% to 10%
tackifier, at least 5% to 10% polarity inducing agent and at least
0.2%) to 0.5%) catalyst by weight of the composition;
b. loading the ingredients of the composition into a screw barrel
extrusion machine;
c. maintaining the screw barrel movement at constant speed and the
temperature inside the screw barrel extrusion machine between
160°Cand 185°C;
d. melting and reacting of the ingredients of the composition inside
the screw barrel extrusion machine and
e. extruding the reacted contents from the screw barrel extrusion
machine as hot melt adhesive film and granule.
2. The method as claimed in claim 1, wherein the recycled plastic granules is
selected from a group of low density poly ethylene (LDPE), linear low
density poly ethylene (LLDPE), high density poly ethylene (HDPE), poly
propylene (PP), biaxially oriented poly propylene (BOPP), poly ethylene
terephthalate (PET), poly vinyl chloride (PVC), ethylene vinyl acetate
(EVA), poly vinyl alcohol (PVA1) and poly vinyl acetate (PVAc).
3. The method as claimed in claim 1, wherein the tackifier used is Poly Iso
Butyl ene.

4. The method as claimed in claim 1, wherein the polarity inducing agent is
selected from:
a. Maleic Anhydride;
b. Acrylic Acid; or
c. combination of both above.
5. The method as claimed in claim 1, wherein the catalyst used is selected
from Dicumyl Peroxide (DCP), Benzoyl Peroxide and Iso Butyl Peroxide.
6. The method as claimed in claim 1, wherein no toxic fumes are evolved,
and no effluent is generated.
7. A composition to make hot melt adhesive film and granules, wherein the
composition comprises of:
a. at least 80% to 90% of recycled plastic granules;
b. at least 4%-10% of tackifier;
c. at least 5%-10% of polarity inducing agent; and
d. at least 0.2% -0.5% of catalyst by weight of the composition.
8. The composition as claimed in claim 7, wherein the recycled plastic granules is selected from low density poly ethylene (LDPE), linear low density poly ethylene (LLDPE), high density poly ethylene (HDPE), poly propylene(PP), biaxially oriented poly propylene (BOPP), poly ethylene terephthalate (PET), poly vinyl chloride (PVC), ethylene vinyl acetate (EVA), poly vinyl alcohol (PVA1) and poly vinyl acetate (PVAc).
9. The composition as claimed in claim 7, wherein the tackifier used is Poly Iso Butyl ene.

Internal Ref: OR19C017
10. The composition as claimed in claim 7, wherein polarity inducing agents
is selected from:
a. Maleic Anhydride;
b. Acrylic Acid; or
c. combination of both above.
11. The composition as claimed in claim 7, wherein the catalyst used is
selected from Dicumyl Peroxide (DCP), Benzoyl Peroxide and Iso Butyl
Peroxide.