Description:Technical field of the invention:
The present invention is related to a biodegradable additive for imparting and enhancing/ accelerating degradation of a polyolefin-based polymer and film thereof.

Particularly, the biodegradable additive of the invention is physically blended with polyolefin-based polymer materials and articles are manufactured from the resulting polymeric blend. This additive ensures stability during the shelf life to the polymeric blend as well as articles thereof but it initiates degradation only upon landfilling and enhances / accelerates the degradation under anaerobic bacterial condition after the disposal.

Background of the invention:
Mostly, the plastics withstand the forces of nature. Therefore, plastics are widely used to manufacture various articles which are used frequently in daily life as well as industrial fields including packaging. They are mass-produced industrially and their usage is increasing greatly. Recently, plastic wraps or bags are used by the fast food stores, department or provisional stores, vegetable vendors, etc. or packaging material or various disposable plastic products are widely used. The demand for these disposable plastic products has increased due to hygiene, convenience and inexpensive options.

Currently, the waste plastics are disposed-off either by landfill or incineration. Attempts have been made to recycle certain waste plastic but the scope is limited. The incineration of the waste plastics leads to environmental pollution. In the case of landfill of the waste plastic, it is difficult to secure a landfill site for an ever-increasing amount of plastic waste. Many plastics do not degrade in natural environments, and so in recent years, environmental littering and destruction due to discarded plastics has occurred. The disposable plastic waste products exist semi-permanently in nature and this causes environmental problems like making the ground unstable, emission of large quantities of harmful gases such as carbon monoxide leading to air pollution, etc. This landfilling of plastic waste imposes serious harm to the living.

Accordingly, in recent years, there are attempts made to develop plastics that can be degraded in natural environments upon landfilling.

To overcome the problems imposed due to landfilling of plastic waste, various degradable plastics have been developed. Primarily, the degradable plastics have been manufactured from the expensive raw materials. Secondly, these degradable plastics have weak physical properties and cause difficulties during manufacturing or may damage. The biodegradable polymer can be manufactured by chemical reaction by using suitable raw materials or by adding additives by physically blending with the polymer to make them biodegradable.

The following existing arts used additive to impart biodegradability to thermoplastic polymer after use and upon landfilling:

KR100602386 (B1) disclose the thermoplastic polymer composition which is structurally stable and is decomposed to harmless products by multiple decomposition like photodecomposition, thermal-decomposition, bio-decomposition, chemical decomposition or so on. The thermoplastic polymer composition comprises: 20 wt. % or more of common thermoplastic polymer component; 0.5-50 wt. % of bio decompostable material selected from starch, polysaccharide, cellulose, cellulose derivatives, wax, polycaprolactone and polylactic acid; 0.05-5 wt. % of promoter containing peroxide compound or surfactant; 0.2-10 wt. % of oxidant which is reacted with thermoplastic polymer component to produce peroxides or hydroperoxides; 0.5-6 wt. % of photodecomposition material containing transition metals; 1-50 wt. % of photo oxidants; and 1-50 wt. % of hydrophilic polymer. The thermoplastic polymer of this patent has weak physical properties and high price due to the use of starch-based components. Besides, it has low industrial applicability.

KR20080033620 (A) disclose the additive composition for biodegradation of the polyolefin-based thermoplastic polymer which ensure stability during the service life and decomposition into non-harmful compounds under natural environment after the use. The additive composition for biodegradation of the polyolefin-based thermoplastic polymer comprises, based on 100 wt. % of the total composition: (a) 10-30 wt. % of the conventional thermoplastic polymer; (b) 0.3-30 wt. % of the biodegradable material comprising at least one material selected from polylactic acid, polycaprolactone, aliphatic polyester, polysaccharides and wax; (c) 0.1-5 wt. % of an oxidation accelerator reacting with C-C bonds of the thermoplastic polymer to generate peroxide or hydroperoxide, and comprising at least one material selected from unsaturated fatty acids, liquid edible oil, organic acids and saccharide; (d) 0.1-3 wt. % of a catalyst for the oxidation accelerator, comprising at least one material selected from iron stearate and copper stearate; (e) 20-70 wt. % of an oxidation accelerating aid selected from the group consisting of clay minerals, calcium carbonate, talc, illite and zeolite; and (f) 0.5-15 wt. % of a hydrophilic group-containing polymer comprising at least one of polyvinyl alcohol, polyacrylic acid and polyethylene acrylic acid.
However, manufacturing of these biodegradable films consume a lot of natural resources like land, water and fertilizers. Their density is higher than polyolefin films, hence consumption is more and hence cost is high. These films are weaker than the polyolefin films. Some of the polymers based on PVA are water soluble, hence not suitable for many applications. Starch based films may degrade due to the fungal attack and lose their properties.

Thus, there is a need to develop an additive which can be blended with the polyolefin based polymer without affecting physical properties and remain stable during shelf life but efficiently disintegrate upon landfilling under anaerobic condition.

Objects of the invention:
A primary object of the invention is to provide a biodegradable additive which can be blended with polyolefin based polymer for imparting and enhancing /accelerating degradation of the same upon landfilling under anaerobic condition.

Another object of the invention is to provide the biodegradable additive which can be blended with polyolefin based polymer for imparting and enhancing /accelerating degradation of the same to solve the above-mentioned conventional problems like not fully degradable and exist in partial degradable form in the land.

Yet another object of the invention is to provide the biodegradable additive which can be blended with polyolefin based polymer for imparting and enhancing /accelerating degradation of the same where the blend polymer is stable during the shelf life of the product even in the presence of conditions including oxidation, heat, light, moisture, oxygen, etc.

Yet another object of the invention is to provide the biodegradable additive which can be blended with polyolefin based polymer for imparting and enhancing /accelerating degradation of the same where the additive of the invention causes natural degradation of polymers into harmless compounds under the anaerobic environment.

An additional object of the invention is to provide a biodegradable polyolefin based polymer comprising the biodegradable additive of the present invention, where the polymer is stable during the shelf life with excellent physical properties, easy to produce and inexpensive yet naturally degradable under the anaerobic environment.

Another additional object of the invention is to provide a biodegradable polyolefin based film comprising the biodegradable additive of the present invention, where the film is stable during the shelf life with excellent physical properties, easy to produce and inexpensive yet naturally degradable under the anaerobic environment.

Yet another additional object of the invention is to provide a process to manufacture the biodegradable polyolefin based polymer and film thereof comprising the biodegradable additive of the present invention, where the process is easy and inexpensive.

Summary of the invention:
The films made of polyolefin polymer including low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and polypropylene (PP) are very often used in conventional packaging materials and these packaging materials upon disposal exist semi-permanently in nature, and thus may cause a number of environmental problems and also increase the amount of waste generated. Surprisingly, it is found that when we added a biodegradable additive of the present invention to a polyolefin polymer followed by extrusion to prepare the films, it is imparting and enhancing/accelerating degradation of the films when disposed-off by way of the landfilling under anaerobic condition, but stable during the shelf life. The film of the present invention completely degraded when disposed-off in the land under anaerobic condition in 12 to 14 months.

According to the invention, there is provided a biodegradable additive for imparting and enhancing /accelerating degradation of a polyolefin polymer and film thereof under anaerobic condition, wherein
said additive comprises:
a) At least one catalyst or activator;
b) Filler; and
c) At least one promoter of anaerobic degradation.

Typically, the biodegradable additive comprises:
a) 11 to 12 % at least one catalyst or activator;
b) 18 to 19 % filler; and
c) 70 % at least one promoter of anaerobic degradation.

Typically, the at least one catalyst or activator is selected from Cobalt Sulphate, Copper Sulphate, Ferrous Sulphate, Manganese Sulphate, and/or Titanium Dioxide

Typically, the filler is selected from Calcium Carbonate, Calcium Sulphate Monohydrate or Calcium Sulphate Dihydrate.

Typically, the at least one promoter of anaerobic degradation is selected from Di-ammonium Phosphate, Potassium Dihydrogen Phosphate, Dicyandiamide and/or Soya Lecithin Powder

Typically, the biodegradable additive comprises:
a) the at least one catalyst or activator selected from Cobalt Sulphate, Copper Sulphate, Ferrous Sulphate, Manganese Sulphate and Titanium Dioxide;
b) the filler selected from Calcium Carbonate, Calcium Sulphate Monohydrate or Calcium Sulphate Dihydrate; and
c) the at least one promoter of anaerobic degradation selected from Di-ammonium Phosphate, Potassium Dihydrogen Phosphate, Dicyandiamide, and Soya Lecithin Powder.

Typically, the biodegradable additive comprises:
a) the catalyst or activator comprises 3.30 wt. % of Cobalt Sulphate, 0.0075 wt. % of Copper Sulphate, 0.45 wt. % of Ferrous Sulphate, 0.33 wt. % of Manganese Sulphate and 7.5 wt. % of Titanium Dioxide;
b) the filler comprises 8.41 wt. % of Calcium Carbonate; and
c) the promoter of anaerobic degradation comprises 14 wt. % of Di-ammonium Phosphate, 37 wt. % of Potassium Dihydrogen Phosphate, 14 wt. % of Dicyandiamide and 5 wt. % of Soya Lecithin Powder.

According to the invention, there is also provided a biodegradable polyolefin polymer; wherein the polymer comprises at least 1000 ppm of the biodegradable additive of the present invention (by weight of the polymer).

Typically, the biodegradable polyolefin polymer comprises the biodegradable additive of the present invention in the range of 1000 to 2000 ppm (by weight of the polymer).

The biodegradable polyolefin polymer of the invention is further used to prepare the film. The film is found to be stable during the shelf life of 5 years.

According to the invention, there is also provided a biodegradable film; wherein the film comprises at least 1000 ppm of the biodegradable additive of the present invention (by weight of the polymer).

Typically, the biodegradable film comprises the biodegradable additive of the present invention in the range of 1000 to 2000 ppm (by weight of the polymer).

The film prepared from the biodegradable polyolefin polymer of the present invention, upon the expiration of shelf life, is landfilled under the land and is found to be degraded completely in 12 to 14 months.

According to the invention there is also provided a process to manufacture the biodegradable polyolefin polymer of the invention and biodegradable film thereof, wherein the process comprising:
1. mixing a polyolefin polymer and the biodegradable additive of the present invention in the ratio of 90 to 80 : 10 to 20 wt./wt. followed by extrusion of the mixture at a rpm in the range of 80-100 rpm and a temperature in the range of 130 to 160°C to obtain a master batch comprising the biodegradable additive of the present invention; and
2. extruding the master batch and a virgin polymer in the ratio of 1 to 2: 98 to 99 wt./wt. at temperature in the range of 160 to 185°C to obtain a biodegradable polyolefin polymer of the present invention;
3. stretching the biodegradable polyolefin polymer of the present invention and further blown with air to obtain a biodegradable polyolefin film of the present invention;
said film is degradable when disposed-off by way of the landfilling under anaerobic condition but stable during the shelf life.

Typically, the polymer is selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and polypropylene (PP).

The biodegradable polyolefin polymer and film thereof of the present invention manufactured by the process of the present invention is observed to be degraded completely in 12 to 14 months, when disposed-off by way of landfilling under anaerobic conditions. However, the polymer is stable with excellent physical properties during the shelf life of the product even in the presence of conditions including oxidation, heat, light, moisture, oxygen, etc. It is also observed that the polymer is easy to produce and inexpensive yet naturally degradable under the anaerobic environment.

Detailed description of the invention:
The terms “a,” “an,” “the” and similar referents used in the context of describing the invention following claims are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

Certain embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the below-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

The percentage (%) or ppm mentioned herein is the percentage of each component calculated based on the total composition of the additive of the present invention or the composition of biodegradable polyolefin polymer of the present invention.

Polyolefin polymers including linear low density polyethylene, high density polyethylene, low density polyethylene, polypropylene, and other resins are thermoplastic. These polymers are taught by the literature as not biodegradable or only very slowly biodegradable. One of the objectives of the present invention is to impart and accelerate biodegradation of a wide range of such polymers to such an extent as to significantly reduce their environmental impact without adversely affecting their desirable physical properties. This objective is achieved by addition of the biodegradable additive of the present invention into the polymer composition.

The biodegradation of the biodegradable polymers is generally occurred by enzyme-catalyzed hydrolysis, oxidation, and/or reduction. Biodegradation is a functional decay of material upon exposure to a living environment, in terms of loss of strength, substance, transparency or good dielectric properties. In biodegradation, the high molecular weight polymers degrade to low molecular weight compounds due to the action of micro- and / or macro-organisms naturally. The rate of their biodegradation may vary from hours to years depending on the nature of the functional group and degree of complexity. This biodegradation can be accelerated by using the catalyst.

One embodiment of the present invention provides for imparting and enhancing /accelerating biodegradation of a polyolefin polymer and film thereof under anaerobic condition by means of additive. When the polymer comprises the additive of the present invention then it is more susceptible to degradation.

The biodegradable additive of the present invention which imparts and enhances /accelerates degradation of a polyolefin polymer and film thereof under anaerobic condition comprises:
a) At least one catalyst or activator;
b) filler; and
c) At least one promoter of anaerobic degradation.

In the present invention, the proportion of at least one catalyst or activator; filler; and at least one promoter of anaerobic degradation in the additive is important to achieve attributes like polymer comprising the additive of the present invention is stable during shelf life but imparts and enhances /accelerates degradation of the polyolefin polymer under anaerobic condition upon landfilling. If at least one catalyst or activator or at least one promoter of anaerobic degradation is eliminated from the additive, then it will adversely affect attributes like complete biodegradation of the polymer upon landfilling and unable to solve the conventional problems like not fully degradable and exist in partial degradable form in the land.

Preferably, the biodegradable additive comprises:
a) 11 to 12 % at least one catalyst or activator;
b) 18 to 19 % filler; and
c) 70 % at least one promoter of anaerobic degradation.

The catalyst or activator is selected from Cobalt Sulphate, Copper Sulphate, Ferrous Sulphate, Manganese Sulphate and/ or Titanium Dioxide.
The filler is selected from Calcium Carbonate, sparingly water soluble product such as Calcium Sulphate Monohydrate or Calcium Sulphate Dihydrate.
The promoter of anaerobic degradation is selected from Di-ammonium Phosphate, Potassium Dihydrogen Phosphate, Dicyandiamide and/ or Soya Lecithin Powder.

The catalyst or activator is chosen very carefully and it is used in the combination and also in very specific proportions in the present invention. Similarly, the promoter of anaerobic degradation is chosen very carefully and it is used in the combination and also in very specific proportions in the present invention.

Typically, the biodegradable additive of the present invention comprises:
a) the catalyst or activator selected from Cobalt Sulphate, Copper Sulphate, Ferrous Sulphate, Manganese Sulphate and Titanium Dioxide;
b) the filler selected from Calcium Carbonate, Calcium Sulphate Monohydrate or Calcium Sulphate Dihydrate; and
c) the promoter of anaerobic degradation selected from Di-ammonium Phosphate, Potassium Dihydrogen Phosphate, Dicyandiamide and Soya Lecithin Powder.

Preferably, the biodegradable additive of the present invention comprises:
a) the catalyst or activator comprises 3.30 wt. % of Cobalt Sulphate, 0.0075 wt. % of Copper Sulphate, 0.45 wt. % of Ferrous Sulphate, 0.33 wt. % of Manganese Sulphate and 7.5 wt. % of Titanium Dioxide;
b) the filler comprises 18.41 wt. % of Calcium Carbonate; and
c) the promoter of anaerobic degradation comprises 14 wt. % of Di-ammonium Phosphate, 37 wt. % of Potassium Dihydrogen Phosphate, 14 wt. % of Dicyandiamide and 5 wt. % of Soya Lecithin Powder.

The additive is prepared by mixing the components namely Calcium Carbonate with Titanium Dioxide, Cobalt Sulphate, Manganese Sulphate, Ferrous Sulphate and Copper Sulphate by dissolving in minimum amount of water in a specific proportion as stated above to obtain a mixture. This mixture is dried in an oven at 120°C. The dried material is collected in the form of lumps. These lumps are grinded along with Diammonium Phosphate, Potassium Dihydrogen phosphate, Dicyandiamide and Soya Lecithin powder to obtain a biodegradable additive in a specific proportion as stated above to obtain the biodegradable additive of the present invention. The additive of the present invention is blended with polyolefin to produce a polymer material which is stable during shelf life but imparts and enhances /accelerates degradation of the polyolefin polymer under anaerobic condition when it is disposed-off by landfilling. This material may be stable because of an induction time before degradation may be initiated.

Another embodiment of the present invention provides a biodegradable polyolefin polymer; wherein the polymer comprises at least 1000 ppm of biodegradable additive of the present invention (by weight of the polymer).

Preferably, the biodegradable polyolefin polymer comprises the biodegradable additive of the present invention in the range of 1000 to 2000 ppm (by weight of the polymer).

The biodegradable polyolefin polymer of the invention is further used to prepare the film.

Yet another embodiment of the present invention provides a biodegradable film; wherein the biodegradable film comprises at least 1000 ppm of biodegradable additive of the present invention (by weight of the polymer).

Preferably, the biodegradable film comprises the biodegradable additive of the present invention in the range of 1000 to 2000 ppm (by weight of the polymer).

The film of the present invention is found to be stable during the shelf life of 5 years.

The film of the present invention upon the expiration of shelf life is disposed-off by landfilling and is found to be decomposed and degraded completely in 12 to 14 months.

Typically, the polymer used in the biodegradable polymer of the invention is selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and polypropylene (PP).

Yet another embodiment of the present invention provides a process to manufacture the biodegradable polyolefin polymer of the present invention and biodegradable film of the present invention.

A polyolefin polymer and the biodegradable additive of the present invention is mixed in the ratio of 90 to 80: 10 to 20 wt./wt. and further the mixture is extruded at a rpm in the range of 80-100 rpm and temperatures in the range of 130 to 160°C to obtain a master batch comprising the biodegradable additive of the present invention.
The master batch obtained is extruded with a virgin polymer in the ratio of 1 to 2: 98 to 99 wt./wt. at temperatures in the range of 160 to 185°C to obtain a biodegradable polyolefin polymer. The extruded mixture is stretched and blown with air to obtain a biodegradable polyolefin film.
The film obtained according to the invention is biodegradable when disposed-off by way of the landfill under anaerobic conditions but stable during the shelf life.

The biodegradable polyolefin polymer of the present invention manufactured by the process of the invention as well as the biodegradable film of the present invention manufactured by the process of the invention is observed to be degraded completely in 12 to 14 months when disposed-off by landfilling under anaerobic conditions. However, the polymer is stable with excellent physical properties during the shelf life (4 to 5 years) of the polymer /film even in the presence of conditions including oxidation, heat, light, moisture, oxygen, etc. It is also observed that the polymer is easy to produce and inexpensive yet naturally degradable under the anaerobic environment

The present invention can be illustrated with the below mentioned examples and comparative examples but not by way of limitations. In other words, exemplary illustrations of the operation of the present invention, the practice of its formulation and rendering of the disclosed process are described in the following examples. In addition to the preferred modes of operation, a practitioner of sufficient skill in the art will appreciate that the metes and bounds of the present invention are not limited by the specific instances described herein, rather are defined by the equivalents provided by the claims of the present invention.

Example 1:
The biodegradable additive of the invention was prepared according to the formulation in Table 1:
Table 1: Formulation A of the biodegradable additive of the present invention

Sr. No. Ingredients Formulation A
% (By wt.)
1 Catalyst or Activator 11.5875
Cobalt Sulphate 3.30
Copper Sulphate 0.0075
Ferrous Sulphate 0.45
Manganese Sulphate, 0.33
Titanium Dioxide 7.5
2 Filler 18.4125
Calcium Carbonate 18.4125
3 Promoter of anaerobic degradation 70
Di-ammonium Phosphate 14
Potassium Dihydrogen Phosphate 37
Dicyandiamide 14
Soya Lecithin Powder 5

18.4125 Kg of Calcium Carbonate was loaded in a ribbon blender. To this, 7.5 Kg of Titanium Dioxide was added in the above ribbon blender and mixed well for 15 minutes. 3.30 Kg of Cobalt Sulphate was dissolved in 3.5 Kg of water followed by loading the same on powder mixture in the ribbon blender and mixed. 0.33 kg of Manganese Sulphate was dissolved in 0.6 Kg of water followed by loading the same in the ribbon blender and mixed. 0.45 Kg of Ferrous Sulphate was dissolved in in 0.6 Kg of water followed by loading the same in the ribbon blender and mixed. 0.0075 Kg of Copper Sulphate was dissolved in 50 gms of water followed by loading the same in the ribbon blender and mixed. The mixture in the ribbon blender was mixed for 15-20 minutes. The mixture was poured in a tray and the same was dried in an oven at 120°C. The dried material was collected in the form of lumps. These lumps were ground along with 14 Kg Di-ammonium Phosphate, 37 Kg Potassium Dihydrogen Phosphate, 14 Kg Dicyandiamide and 5 Kg Soya Lecithin Powder on Multi mill to obtain the biodegradable additive having Formulation A.

Master Batch
Master Batch Processing Parameters:
Feed RPM:15-20
Screw RPM: 80-100
Torque: 25-30%
Output rate: 2-2.5 kg/hr
Temperature profile of extruder during Master Batch:
Zone B2 B3 B4 B5 B6 B7 B8 B9 B10 Die Ad Die
°C 150 150 145 145 145 145 145 150 150 155 160

Master Batch A with 10 % Formulation A of the biodegradable additive of the present invention according to table 1:
The extruder was heated to 130°C (processing temperature is to be set according to the melting point of LLDPE). The LDPE polymer was mixed with 10 % of the Formulation A of the biodegradable additive of the present invention (according to table 1). The mixture was charged into a volumetric feeder by increasing RPM to 80 and further set at 14 RPM. The mixture proceeded through a twin-screw where it was homogeneously mixed with LLDPE matrix at 80 RPM in heated conditions from zones B2 to B10. The hot melt strand came out from a two-strand die (Die AD and Die heated at 155°C and 160°C) and was passed through rollers of a water bath where it solidified. The strands were passed through the air knife to remove excess water and further dried. The strands were cut into granule forms with the help of a high-speed cutter to obtain a Master Batch A comprising 10 % biodegradable additive having Formulation A according to table 1. The colour of the master batch A stabilized to light brown.

Master Batch B with 20 % Formulation A of the biodegradable additive of the present invention according to table 1:
The extruder was heated to 130°C (processing temperature is to be set according to the melting point of LLDPE). The LDPE polymer was mixed with 20 % of the Formulation A of the biodegradable additive of the present invention (according to table 1). The mixture was charged into a volumetric feeder by increasing RPM to 80 and further set at 14 RPM. The mixture proceeded through a twin-screw where it was homogeneously mixed with LLDPE matrix at 80 RPM in heated conditions from zones B2 to B10. The hot melt strand came out from a two-strand die (Die AD and Die heated at 155°C and 160°C) and was passed through rollers of a water bath where it solidified. The strands were passed through the air knife to remove excess water and further dried. The strands were cut into granule forms with the help of a high-speed cutter to obtain a Master Batch B comprising 20 % biodegradable additive having Formulation A according to table 1. The colour of the master batch B stabilized to light brown.

Biodegradable Polymer and Films
Processing Parameters:
Feed RPM: 285
Screw RPM: 320
Output rate: 600 gm/hr
Thickness: 50 µm
Temperature profile:
Zone Z1 Z2 Z3 Z4 Z5
°C 160 170 175 180 185

Biodegradable Polymer and Biodegradable Film A comprising with 1 % of Formulation A of the biodegradable additive of the present invention according to table 1:
1 Kg Master Batch A and 99 Kg LDPE polymer were mixed into the hopper and processed in the extruder as per the above-mentioned parameters. A melt of biodegradable polymer came out from the crosshead die. The film was pulled slowly by a plier and it was passed from the collapsing grid to the pulling roller. Guide collapsed the film through Guide rollers and attached it to the winding roller. The film was punched and provided with air to blow it according to the required size. After achieving the desired thickness of 50 µm, a tube was cut at the winding roller end and attached to the unit. After adjusting tube size according to the 50 µm thickness, film A was wound on the roller.
The film A has shelf life: 5 years.
Biodegradable Polymer and Biodegradable Film B comprising with 2 % of Formulation A of the biodegradable additive of the present invention according to Table 1:
2 Kg Master Batch B and 98 Kg LDPE polymer were mixed into the hopper and processed in the extruder as per the above-mentioned parameters. A melt came out from the crosshead die. The film was pulled slowly by a plier and it was passed from the collapsing grid to the pulling roller. Guide collapsed the film through Guide rollers and attached it to the winding roller. The film was punched and provided with air to blow it according to the required size. After achieving the desired thickness of 50 µm, a tube was cut at the winding roller end and attached to the unit. After adjusting tube size according to the 50 µm thickness, film B was wound on the roller.
The film B has shelf life: 5 years.
Comparative Example 1:
The comparative additive was prepared according to the formulation in Table 2:

Table 2: Formulation B of the comparative additive

Sr. No. Ingredients Formulation B
% (By wt.)
1 Catalyst or Activator 38.625
Cobalt Sulphate 11
Copper Sulphate 0.025
Ferrous Sulphate 1.50
Manganese Sulphate, 1.10
Titanium Dioxide 25
2 Filler 61.375
Calcium Carbonate 61.375
3 Promoter of anaerobic degradation 0
Di-ammonium Phosphate -
Potassium Dihydrogen Phosphate -
Dicyanadiamide -
Soya Lecithin Powder -

61.375 Kg of Calcium carbonate was loaded in a ribbon blender. To this, 25Kg of Titanium Dioxide was added in the above ribbon blender and mixed well for 15 minutes. 11 Kg of Cobalt Sulphate was dissolved in 11 Kg of water followed by loading the same on powder mixture in the ribbon blender and mixed. 1.10 kg of Manganese Sulphate was dissolved in 2 Kg of water followed by loading the same in the ribbon blender and mixed. 1.50 Kg of Ferrous Sulphate was dissolved in 2 Kg of water followed by loading the same in the ribbon blender and mixed. 0.025 Kg of Copper Sulphate was dissolved in 100 gms of water followed by loading the same in the ribbon blender and mixed. The mixture in the ribbon blender was mixed for 15-20 minutes. The mixture was poured in a tray and the same was dried in an oven at 120°C. The dried material was collected in the form of lumps. These lumps were ground on Multi mill to obtain the comparative additive having Formulation B.
Master Batch Processing Parameters:
Feed RPM:15-20
Screw RPM: 80-100
Torque: 25-30%
Output rate: 2-2.5 kg/hr
Temperature profile of extruder during Master Batch:
Zone B2 B3 B4 B5 B6 B7 B8 B9 B10 Die Ad Die
°C 150 150 145 145 145 145 145 150 150 155 160

Master Batch C with 10 % Formulation B of the comparative additive according to the Table 2:
The extruder was heated to 130°C (processing temperature is to be set according to the melting point of LLDPE). The LDPE polymer was mixed with 10 % of the Formulation B of the comparative additive according to the table 2. The mixture was charged into a volumetric feeder by increasing RPM to 80 and further set at 14 RPM. The mixture proceeded through a twin-screw where it was homogeneously mixed with LLDPE matrix at 80 RPM in heated conditions from zones B2 to B10. The hot melt strand came out from a two-strand die (Die AD and Die heated at 155°C and 160°C) and was passed through rollers of a water bath where it solidified. The strands were passed through the air knife to remove excess water and further dried. The strands were cut into granule forms with the help of a high-speed cutter to obtain a Master Batch C comprising 10 % comparative additive having Formulation B according to the table 2. The colour of the master batch A stabilized to light brown.

Master Batch D with 20 % Formulation B of the comparative additive according to Table 2:
The extruder was heated to 130°C (processing temperature is to be set according to the melting point of LLDPE). The LDPE polymer was mixed with 20 % of the Formulation B of the comparative additive according to the table 2. The mixture was charged into a volumetric feeder by increasing RPM to 80 and further set at 14 RPM. The mixture proceeded through a twin-screw where it was homogeneously mixed with LLDPE matrix at 80 RPM in heated conditions from zones B2 to B10. The hot melt strand came out from a two-strand die (Die AD and Die heated at 155°C and 160°C) and was passed through rollers of a water bath where it solidified. The strands were passed through the air knife to remove excess water and further dried. The strands were cut into granule forms with the help of a high-speed cutter to obtain a Master Batch D comprising 20 % comparative additive having Formulation B according to the table 2. The colour of the master batch B stabilized to light brown.

Biodegradable Polymer and Films
Processing Parameters:
Feed RPM: 285
Screw RPM: 320
Output rate: 600 gm/hr
Thickness: 50 µm
Temperature profile:
Zone Z1 Z2 Z3 Z4 Z5
°C 160 170 175 180 185

Biodegradable Polymer and Biodegradable Film C comprising with 1 % of Formulation B of the comparative additive according to the table 2:
1 Kg Master Batch C and 99 Kg LDPE polymer were mixed into the hopper and processed in the extruder as per the above-mentioned parameters. A melt of biodegradable polymer came out from the crosshead die. The film was pulled slowly by a plier and it was passed from the collapsing grid to the pulling roller. Guide collapsed the film through Guide rollers and attached it to the winding roller. The film was punched and provided with air to blow it according to the required size. After achieving the desired thickness of 50 µm, a tube was cut at the winding roller end and attached to the unit. After adjusting tube size according to the 50 µm thickness, film C was wound on the roller.
The film C has shelf life: 4 years.
Biodegradable Polymer and Biodegradable Film D comprising with 2 % of Formulation B of the comparative additive according to the table 2:
2 Kg Master Batch D and 98 Kg LDPE polymer were mixed into the hopper and processed in the extruder as per the above-mentioned parameters. A melt came out from the crosshead die. The film was pulled slowly by a plier and it was passed from the collapsing grid to the pulling roller. Guide collapsed the film through Guide rollers and attached it to the winding roller. The film was punched and provided with air to blow it according to the required size. After achieving the desired thickness of 50 µm, a tube was cut at the winding roller end and attached to the unit. After adjusting tube size according to the 50 µm thickness, film D was wound on the roller.
The film D has shelf life: 4 years.
Degradation Study:
The Film A, Film B, Film D, Film made of LDPE without additive (control) were landfilled and degradation study under anaerobic conditions was done every two months by testing its percentage elongation (By ASTM D 882). The testing parameters are as follows:
Instrument details:
Model Name: Universal Testing Machine
Manufacturer: International Equipment
Test Condition:
Conditioning: 24 hrs at Room Temp (25 ± 2 0C)
Relative Humidity: 50 ± 5%
Materials:
2, 4, 6, 8, 10, 12, 14 months exposed Control LDPE film
2, 4, 6, 8, 10, 12, 14 months exposed Film A
2, 4, 6, 8, 10, 12, 14 months exposed Film B
2, 4, 6, 8, 10, 12, 14 months exposed Film D
Sample size: 25 x100 x 0.04-0.05 mm.
The results of degradation study of the film A and B against Film D and Control films is tabulated in table 3.

Table 3: Degradation study results

Film Percentage Elongation
Before Exposure After 2 months After 4 months After 6 months After 8 months After 10 months After 12 months After 14 months % Degradation
Control 176.66 171.4 164.34 139.66 119.16 91.86 67.13 42.39 76
Film D 146.08 136.7 131.80 110.06 91.44 70.11 51.13 30.67 79
Film A 151.26 132.57 129.70 106.38 76.67 51.42 24.20 0 100
Film B 157.34 127.54 116.22 98.95 55.42 29.89 0 - 100

According to the results illustrated in the Table 3, the Film B comprising 2% biodegradable additive of formulation A of the present invention according to Table 1 demonstrated more degradation by way of reduction in elongation (100 %) in 12 months and completely disintegrated in the land. At the end of 12 months’ time, no micro plastics were observed in soil sample when examined microscopically under SEM.
While Film A comprising 1 % biodegradable additive of formulation A of the present invention according to the Table 1 demonstrated degradation by way of reduction in elongation (100 %) in 14 months and completely disintegrated in the land.
While that of Control film and Film D comprising 2 % comparative additive of formulation B according to the Table 2 demonstrated only 79 % and 76 % degradation respectively by way of reduction in elongation at the end of 14 months. At the end of 18 months’ time, micro plastics were observed in soil sample when examined microscopically under SEM.

Thus, film A and film B of the present invention comprising 1 % to 2% (i.e. 1000 to 2000 ppm) biodegradable additive of formulation A of the present invention degraded in 12 and 14 months respectively under anaerobic conditions and no micro plastics were observed in soil sample. The polymer and film of the present invention is stable with excellent physical properties during the shelf life (5 years) even in the presence of conditions including oxidation, heat, light, moisture, oxygen, etc. The process to manufacture biodegradable polymer and film thereof is easy and inexpensive yet naturally degradable under the anaerobic environment.
, Claims:Claims:
1. A biodegradable additive for imparting and enhancing/ accelerating degradation of a polyolefin polymer and film thereof under anaerobic conditions, wherein
said additive comprises:
a) At least one catalyst or activator;
b) Filler; and
c) At least one promoter of anaerobic degradation.

2. The biodegradable additive as claimed in claim 1, wherein the additive comprises:
a) 11 to 12 % at least one catalyst or activator;
b) 18 to 19 % filler; and
c) 70 % at least one promoter of anaerobic degradation.

3. The biodegradable additive as claimed in claims 1 and 2, wherein the catalyst or activator is selected from Cobalt Sulphate, Copper Sulphate, Ferrous Sulphate, Manganese Sulphate and/or Titanium Dioxide

4. The biodegradable additive as claimed in claims 1 and 2, wherein the filler is selected from Calcium Carbonate, Calcium Sulphate Monohydrate or Calcium Sulphate Dihydrate.

5. The biodegradable additive as claimed in claims 1 and 2, wherein the promoter of anaerobic degradation is selected from Di-ammonium Phosphate, Potassium Dihydrogen Phosphate, Dicyandiamide and/or Soya Lecithin Powder.

6. The biodegradable additive as claimed in claim 1, wherein the biodegradable additive comprises:
a) the at least one catalyst or activator comprises Cobalt Sulphate, Copper Sulphate, Ferrous Sulphate, Manganese Sulphate and Titanium Dioxide;
b) the filler namely Calcium Carbonate, Calcium Sulphate Monohydrate or Calcium Sulphate Dihydrate; and
c) the at least one promoter of anaerobic degradation selected from Di-ammonium Phosphate, Potassium Dihydrogen Phosphate, Dicyandiamide, and Soya Lecithin Powder.

7. A biodegradable polyolefin polymer; wherein the polymer comprises a polyolefin polymer and the biodegradable additive as claimed in any of the claims 1 to 6.

8. The biodegradable polyolefin polymer as claimed in claim 7, wherein the polymer comprises at least 1000 ppm of the biodegradable additive as claimed in any of the claims 1 to 6.

9. The biodegradable polyolefin polymer as claimed in claim 7, wherein the polymer comprises 1000 to 2000 ppm of the biodegradable additive as claimed in any of the claims 1 to 6.

10. The biodegradable polyolefin polymer as claimed in claims 7 to 9, wherein the polymer is selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and polypropylene (PP).

11. A biodegradable film, wherein the film comprises a polyolefin polymer and the biodegradable additive as claimed in any of the claims 1 to 6.

12. The biodegradable film as claimed in claim 11, wherein the film comprises at least 1000 ppm of the biodegradable additive as claimed in any of the claims 1 to 6.

13. The biodegradable film as claimed in claim 11, wherein the film comprises 1000 to 2000 ppm of the biodegradable additive as claimed in any of the claims 1 to 6.

14. The biodegradable film as claimed in claims 11 to 13, wherein the polymer is selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and polypropylene (PP).

15. A process to manufacture the biodegradable polyolefin polymer as claimed in any of the claims 7 to 10 and biodegradable film as claimed in any of the claims 11 to 14, wherein the process comprising:
1) mixing a polyolefin polymer and the biodegradable additive as claimed in any of the claims 1 to 6 in the ratio of 90 to 80: 10 to 20 wt./wt. followed by extrusion of the mixture at a rpm in the range of 80-100 rpm and a temperature in the range of 130 to 160°C to obtain a master batch comprising the biodegradable additive as claimed in claims 1 to 6; and
2) extruding the master batch and a virgin polymer in the ratio of 1 to 2: 98 to 99 wt./wt. at temperature in the range of 160 to 185°C to obtain a biodegradable polyolefin polymer as claimed in claims 7 to 10;
3) stretching the biodegradable polyolefin polymer of step 2 and further blown with air to obtain a biodegradable polyolefin film as claimed in claims 11 to 14;
said film is degradable when disposed-off by way of the landfilling under anaerobic condition but stable during the shelf life.

16. The process as claimed in claim 15, wherein the polymer is selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and polypropylene (PP).

Dated this 18th day of March 2023

(Dr Shilpa H. Gharve)
Agent for the Applicant
(Reg. No. IN/PA 890)