DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION

(See Section 10 and Rule 13)

Title of invention:
A PLASTICIZER AND A THERMOPLASTIC RESIN FORMULATION

APPLICANT:
DEEPAK NITRITE LIMITED
An Indian entity having address as:
Registered & Corporate Office, 2nd Floor, Fermenter House, Alembic City, Alembic Avenue Road, Vadodara - 390 003, Gujarat, India
&
INSTITUTE OF CHEMICAL TECHNOLOGY
An Indian entity having address at:
Nathalal Parekh Marg, Near Khalsa College, Matunga East, Mumbai, Maharashtra 400019

The following specification particularly describes the invention and the manner in which it is to be performed.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
The present application is based on and claiming priority from Indian provisional Application Number 202321038091 filed on 02nd December 2023, the details of which are incorporated herein by a reference.
TECHNICAL FIELD
The present subject matter described herein, in general, relates to a field of polymer and surface chemistry, and more particularly relates to a plasticizer, a thermoplastic resin formulation and method of preparation for various applications, including in packaging materials, consumer goods, construction materials, medical devices and electrical and electronic component.
BACKGROUND
Plasticizers are versatile additives widely used across industries to enhance the properties and processability of various materials. In the case of resins, plasticizers are incorporated to increase flexibility, softness, and plasticity, making the materials easier to shape and manipulate. These substances achieve their effects by reducing intermolecular forces within the material, which also decreases viscosity, improving flow characteristics during manufacturing processes.
Additionally, plasticizers minimize friction, facilitating smoother handling and processing. Beyond polymers, plasticizers play a crucial role in concrete formulations, where they enhance workability and fluidity, enabling easier pouring and placement while reducing the water content needed. This not only improves the strength and durability of the final concrete but also makes the mixing and application more efficient. Thus, plasticizers serve as critical modifiers in both polymer and construction industries, tailoring materials to specific functional and operational requirements.
Application of plasticizers particularly for adding to polymers, plastics, resins such as polyvinyl chloride (PVC) is key for their processability to facilitate handling of the raw material during fabrication, or to meet the requirements of the end product's applications. For instance, in the absence of plasticizers, PVC is rigid, hard and brittle, which on addition of plasticizers makes it is suitable for products such as vinyl siding, roofing, vinyl flooring, rain gutters, plumbing, and electric wire insulation/coating.
Thus, while thermoplastic resins, including but not limited to polyvinyl chloride (PVC), and chlorinated polyvinyl chloride (CPVC), offer a diverse range of properties, these become available for varied end applications only upon formulating with appropriate plasticizers. For instance, PVC, known for its versatility and cost-effectiveness, finds extensive use in construction for pipes, window frames, and cables due to its fire resistance, insulation properties, and durability. CPVC, a chlorinated variant of PVC, shows enhanced heat resistance, making it suitable for hot water plumbing systems and industrial applications where higher temperatures are encountered.
Recycling thermoplastic resins like PVC is essential for sustainable management of polymer waste. However, recycled PVC often contains variable thermal histories and inconsistent formulations due to mixed sources, making it prone to loss of property during processing and reuse. This necessitates the development of advanced additives to improve the desired properties such as thermal stability, UV resistance, overall weatherability, and processability of recycled PVC. These enhanced additives play a critical role in ensuring durability and performance of recycled PVC under challenging environmental conditions, including high temperatures and harmful UV exposure.
Traditionally, the evaluation of plasticizer efficiency involves assessing various parameters, such as changes in glass transition temperature (Tg), mechanical strength, and thermal properties. However, ongoing developments in the industry are focused on improving formulations by seeking cost-effective materials that not only maintain, but may even enhance, performance characteristics. Today’s approach emphasizes sustainability, waste management, and efficiency, with a growing focus on turning waste into value-added products. This shift reflects a commitment to developing solutions that are not only economically viable but also environmentally responsible, aligning with the need for continuous improvement in material performance and resource utilization.
The existing plasticizer components such as chlorinated paraffin wax (CPW), or dibenzyl ether (DBE) are less effective in terms of softness, and processability. There exists a need to address environmental as well as economic considerations while maintaining or surpassing the performance of conventional plasticizers.
The incompatibility between the thermoplastic resin and plasticizer can cause exudation. Several associated factors such as temperature, humidity, mechanical stress, and weathering can lead to migration of the plasticizer from the resin surface. Such loss of plasticizer from the thermoplastic resin can impact flexibility, embrittlement, and cracking of the thermoplastic resin material.
Valorization refers to the extraction, recovery or reuse of valuable compounds from waste materials or co-products of industrial processes and also recycled the plastic and resin articles. By implementing them as plasticizers reduces overall costs and potentially expands the applicability of thermoplastics in diverse sectors.
Therefore, there has always been a long felt need to develop a plasticizer, a thermoplastic resin formulations and method that integrates readily available and economically viable ingredients obtained as a co-product of various industrial processes that may be comparable to or surpass the properties of conventional plasticizers.
SUMMARY
Before the present system and its components are described, it is to be understood that this disclosure is not limited to the particular system and its arrangement as described, as there can be multiple possible embodiments which are not expressly illustrated in the present disclosure. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope of the present application. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in detecting or limiting the scope of the claimed subject matter.
As disclosed herein, the present subject matter relates to a plasticizer and a thermoplastic rein formulation.
In one implementation, a plasticizer formulation for thermoplastic resin comprising one or more nitroxylenes is disclosed.
In another implementation, a thermoplastic resin formulation is disclosed. The formulation may comprise a recycled thermoplastic material, wherein the recycled thermoplastic material comprises a primary plasticizer present in the amount in the range of 15 to 55 phr of the total weight of the recycled thermoplastic material. Further, the formulation may comprise a secondary plasticizer, wherein the secondary plasticizer is one or more nitroxylenes.
BRIEF DESCRIPTION OF FIGURES
The detailed description is described with reference to the accompanying Figures. In the Figures, the left-most digit(s) of a reference number identifies the Figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.
Figure 1 depicts the preparation of an article comprising a thermoplastic resin formulation, in accordance with one embodiment of the present disclosure.
Figure 2 depicts the graphical representation of Fourier-transform infrared spectroscopy (FTIR) analysis for the thermoplastic resin formulation, in accordance with one embodiment of the present disclosure.
Figure 3 depicts the graphical representation of Thermogravimetric analysis (TGA) analysis for the thermoplastic resin formulation, in accordance with one embodiment of the present disclosure.
Figure 4 depicts the graphical representation of Differential scanning calorimetry (DSC) analysis for the thermoplastic resin formulation, in accordance with one embodiment of the present disclosure.
DETAILED DESCRIPTION
Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment” in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
The words “comprising”, “having”, “containing”, and “including”, and other forms thereof are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be exhaustive listing of such item or items or meant to be limited to only the listed item or items. It must also be noted that the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Although any methods similar or equivalent to those described herein may be used in the practice or testing of embodiments of the present disclosure, the exemplary methods are described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
Various modifications to the embodiment may be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, a skilled person in the art may readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein. A detailed description of the invention will be described hereinafter.
The embodiments, examples and alternatives of the preceding paragraphs or the description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
The embodiments, examples and alternatives of the preceding paragraphs or the description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
The present disclosure relates to a plasticizer, a thermoplastic resin formulation and method of preparation. The formulation overcomes the major drawback such as reliance on costly, non-renewable raw materials, limited compatibility with certain thermoplastic resins, and environmental concerns stemming from hazardous co-products. By integrating readily available, cost-effective, and eco-friendly ingredients, often derived from industrial co-products, the disclosed formulation enhances material performance, including flexibility, thermal stability, and mechanical strength. Additionally, the method of preparation ensures efficiency, scalability, and sustainability, making it suitable for diverse applications while aligning with current industrial demands for economical and environmentally responsible solutions.
In an embodiment of the present disclosure, a plasticizer for thermoplastic resin formulation is disclosed. This plasticizer enhances the flexibility, processability, and mechanical properties of the resin while addressing compatibility and sustainability challenges. By utilizing materials such as one or more nitroxylenes, the plasticizer ensures improved performance and cost-effectiveness, making it suitable for a wide range of industrial applications.
Plasticizers increase the flow and thermo-plasticity of the thermoplastic resin polymer. This can be achieved by decreasing the viscosity of polymer melt, glass transition temperature, melting temperature, and elastic modulus of finished articles and products. During this process, the fundamental chemical, thermal, and mechanical characteristics of the plasticized material remains unaltered.
The plasticizer formulation may comprise a primary plasticizer and a secondary plasticizer. A primary plasticizer contributes to enhance elongation, softness and flexibility of polymer. The primary plasticizers are highly compatible with polymers and can be added in significant quantities depending on the formulation and application requirement.
A secondary plasticizer may not typically be used as the stand-alone plasticizer in a specific polymer system. Secondary plasticizers may have limited compatibility with the polymer and/or high volatility. Secondary plasticizers are variously used for product cost reduction, viscosity reduction, solvency enhancement of the polymer material, surface lubricity, and low temperature flexibility enhancement.
In a related embodiment, the plasticizer for thermoplastic resin formulation is one or more nitroxylene, a compound selected for its ability to enhance the flexibility, durability, and overall performance of thermoplastic materials in a cost-effective manner. The one or more nitroxylenes demonstrates excellent compatibility with a wide range of resins, effectively reducing brittleness and improving processability. Its unique chemical properties make it an efficient and reliable choice for industrial applications, offering cost advantages while maintaining or surpassing the performance of conventional plasticizers.
The one or more nitroxylenes are large-scale co-products formed during certain industrial processes particularly those involving nitration products of xylene or related aromatic compounds. The applicability of one or more nitroxylenes is assessed as a secondary plasticizer for plastics and thermoplastic resins.
In another related embodiment, the one or more nitroxylenes is a secondary plasticizer which is recovered as co-products of industrial processes, aligning with the principles of waste valorisation by transforming recovered co-products into value-added products. By recovering the one or more nitroxylenes from reaction streams, this approach not only provides an economically viable source of plasticizer but also addresses environmental challenges by achieving recycle and reuse of the thermoplastic materials while maintaining their desired properties. As a secondary plasticizer, the one or more nitroxylenes enhances the flexibility and processability of thermoplastic resin formulations while complementing the primary plasticizer to optimize the material’s mechanical and thermal properties.
In yet another related embodiment, the one or more nitroxylenes is selected from 3-nitro-o-xylene, 4-nitro-o-xylene, 4-nitro-m-xylene, 2-nitro-m-xylene, 5-nitro-m-xylene, 2-nitro-p-xylene or combinations thereof.
These compounds, characterized by their nitro-functionalized aromatic structures, offer tailored plasticizing properties that enhance the flexibility, processability, and performance of thermoplastic resin formulations. By utilizing different isomers of nitroxylene, it is possible to fine-tune the properties of the plasticizer to meet specific application requirements, such as improved thermal stability, processability, low volatility and optimized compatibility with various resins.
In an embodiment, the thermoplastic resin formulation is disclosed. The thermoplastic resin formulation comprises of a recycled thermoplastic material, wherein the recycled thermoplastic resin formulation is durable and can undergo multiple recycle without losing the desired properties. Further, the thermoplastic resin formulation material comprises a primary plasticizer present in the amount in the range of 15 to 55 phr of the total weight of the recycled thermoplastic material. The primary plasticizer plays a crucial role in improving the flexibility, softness, processability, outdoor weatherability, plasticizer solvency, flame retardancy, high and low temperature compatibility, and hydrolysis resistance of the resin, enabling it to meet performance requirements for various industrial applications.
The primary plasticizer may any of of but not limited to phthalates, polyesters, aliphatic dibasic acid esters, citrates, bio-based plasticizers, other terephthalates, trimellitates, phosphates, benzoates and others.
Phthalates may comprise one or more phthalate esters such as di-2-ethylhexyl-phthalate (DEHP), Diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and dibutyl phthalate (DBP), dihexyl phthalate (DHP), diisooctyl phthalate (DIOP), butyl benzyl phthalate (BBP), diisoheptyl phthalate (DIHP), di-iso-undecyl phthalate (DIUP), dimethyl phthalate (DMP), diisotridecyl phthalate (DTDP), and dioctyl phthalate (DOP) and the like.
Aliphatic dibasic acid esters may comprise one or more glutarates, adipates, azelates and sebacates such as but not limited to di-2-ethylhexyl sebacate (DOS), di-2-ethylhexyl azelate (DOZ), di-isodecyl sebacate (DIDS).
Also, the primary plasticizers are any one of phosphates comprising triaryl phosphates, alkyl diaryl phosphate esters; trimellitate esters selected from trimellitic anhydride (TMA), aliphatic dibasic acids such as adipic acid and diols; and bio-based plasticizers selected from epoxidized soybean oil (ESBO), epoxidized linseed oil (ELO), soybean oil, castor oil, palm oil, other vegetable oils, starches, sugars including isosorbide esters, and others.
The thermoplastic resin formulation achieves a fine balance between mechanical strength, thermal stability, and ease of processing, making the thermoplastic resin formulation suitable for diverse production techniques and target applications. Additionally, it is recyclable and durable, maintaining its core properties through multiple cycles. With added resistance to problems such as microbial growth, this thermoplastic resin formulation offers an environmentally responsible solution for high-performance applications.
In an embodiment, the recycled thermoplastic material of the thermoplastic resin formulation comprises polyvinyl chloride (PVC), and chlorinated polyvinylchloride (CPVC) or combinations thereof. PVC, a widely used and versatile thermoplastic, is chosen for its excellent durability, chemical resistance, and ease of processing. CPVC offers enhanced thermal and chemical resistance due to the chlorination process, making it ideal for applications requiring higher temperature resistance or exposure to harsh chemicals.
By incorporating recycled versions of these materials, the formulation not only takes advantage of the inherent properties of these resins but also supports environmental sustainability and economic benefits by reusing materials that would otherwise contribute to waste. In an embodiment, the formulation may comprise recycled PVC, recycled CPVC or their combination that allows for customization of the formulation to suit specific mechanical, and thermal performance requirements across a variety of applications.

In a related embodiment, the recycled thermoplastic material is present in an amount in the range of 50-80% of the total weight of the formulation. Preferably, the recycled thermoplastic material is present in an amount in the range of 60-70% of the total weight of the formulation.
In an embodiment, the thermoplastic resin formulation comprises of a secondary plasticizer. The secondary plasticizer is typically added in smaller amounts compared to the primary plasticizer but plays a vital role in improving the flexibility, processing characteristics, and overall performance of the thermoplastic resin. It helps to maintain the balance between rigidity and softness, providing enhanced durability and resistance to thermal degradation.
The choice of secondary plasticizer, such as the one or more nitroxylenes, allows for customization of the formulation to meet specific application requirements, such as better compatibility with different resin types, improved mechanical strength, or greater cost-effectiveness. By incorporating a secondary plasticizer, the formulation benefits from improved processing efficiency and extended material properties, making it suitable for a wide range of industrial and commercial applications.
In a related embodiment, the secondary plasticizer is present in an amount in the range of 0.1 to 30 parts per hundred resins (phr). Preferably, the secondary plasticizer is present in an amount in the range of 5-25 phr.
In an embodiment, the formulation comprises of one or more additives selected from stabilizers, lubricants, fillers as well as swelling agents. Additives are significant in shaping formulation properties and influencing product quality by adjusting and fine-tuning the characteristics of thermoplastics to create products tailored for diverse applications requiring varying degrees of flexibility.
Amongst them, stabilizers are essential for their critical role in preventing degradation and maintaining the integrity of the final product. Several types of stabilizers commonly used, including antioxidants, UV stabilizers, heat stabilizers, and light stabilizers.
Antioxidants inhibit oxidation reactions that can cause polymer degradation, while UV stabilizers absorb or scatter ultraviolet radiation to protect against photochemical degradation.
Heat stabilizers prevent thermal degradation at elevated temperatures, and light stabilizers protect against degradation induced by exposure to sunlight or artificial light sources. In a preferred embodiment, the stabilizers may be selected from lead salts, organotin compounds, barium, cadmium and zinc salts, organic phosphates, polyols, calcium/zinc stabilizers, lead stearate and organic tin/calcium-zinc hybrid stabilizers etc.
Lubricants are additives indispensable in various industries, particularly in polymer processing, where they facilitate the smooth and efficient manufacturing of plastic products. They get incorporated into polymer formulations reducing friction between polymer chains and processing equipment, thereby enhancing flow properties, and preventing melt fracture during extrusion or molding processes. Lubricants also aid dispersion of other additives, improve surface finish, and prevent adhesion. In a preferred embodiment, lubricants may be selected from the paraffin wax, polyethylene wax, Fischer-Tropsch wax, oxidized polyethylene wax, ester wax, stearic acid and metal stearates etc.
Fillers are integral components in polymer formulations for enhancing the properties and performance of the final product. Fillers modify mechanical, thermal, and electrical properties, as well as to reduce costs and improve processability of the polymers. They are typically inert materials added to the polymer matrix in varying concentrations, ranging from a few percent to as high as 50% or more. for imparting stiffness, strength, and dimensional stability to the polymer, making it suitable for a wide range of applications. Types of fillers include minerals such as calcium carbonate, talc, and silica, as well as organic fillers like wood flour, cellulose, and glass fibers. Additionally, fillers can help reduce shrinkage and warpage during processing, leading to enhanced dimensional accuracy and surface finish in moulded or extruded parts. In a preferred embodiment, fillers may be selected from calcium carbonate, titanium dioxide, dolomite, zinc oxide, mica, talc, barium sulphate and silica etc.
Swelling agents are substances that have the remarkable ability to increase in volume when they come into contact with water or other liquids. In a preferred embodiment, swelling agents may be selected from benzene, toluene, xylene, carbon tetrachloride, methylene dichloride, 1-chlorobutane, 1-chlorohexane, 1-chloroethane, 1-chlorodecane, Bromo-chlorobenzene, bromonaphtol, bromo-hydroxybenzene, carbon tetrabromide, dichloro-nitrobenzene etc.
In a preferred embodiment, the formulation comprises of one or more additives such as heat stabilizers and lubricants. Heat stabilizers are employed to prevent degradation or loss of efficacy of the formulation when exposed to elevated temperatures, ensuring its integrity and functionality over time. Lubricants, on the other hand, serve to reduce friction between particles, facilitating the manufacturing process and improving the consistency and quality of the final product. By integrating these additives into the formulation, the overall effectiveness and reliability of the product are bolstered, meeting the desired standards of performance and durability.
Thus, the plasticizer formulations comprising one or more nitroxylenes of the instant invention further comprising additives provides formulations having a range of desired properties of density, viscosity, tensile strength, softening temperatures etc.
In an embodiment, the formulation has a density in the range between 1.535 to 1.575 gm/ml at a temperature in the range between 20-30°C. Preferably, the formulation has a density in the range between 1.545 to 1.565 gm/ml at a temperature in the range between 22-28°C.
In an embodiment, the formulation has a softening temperature in the range between 65-85°C. Preferably, the softening temperature is in the range between 70-80°C. This targeted range offers enhanced mechanical properties, improved dimensional stability, and better adaptability to operational environments where precise thermal responses are critical. The defined softening temperature range thus makes the formulation suitable for applications requiring controlled thermal transitions, ensuring consistent performance and reliability.
In an embodiment, the formulation has a tensile strength in the range between 5-15Mpa. Preferably, the tensile strength is in the range between 7-13Mpa. This range ensures the material can withstand moderate mechanical stress while maintaining its integrity, making it particularly suitable for applications where controlled strength and resilience are essential for performance and reliability.
In an embodiment, the formulation has a % of elongation in the range between 150-170%. Preferably, the % of elongation is in the range between 152-168%. Due to this % of elongation the material can adapt to dynamic stresses, impact resistance and strains without compromising performance, making it ideal for applications requiring high flexibility and durability under repeated mechanical loading.
In an embodiment, the formulation has shore D-hardness in the range between 40-60 shore D. Preferably, the shore D-hardness is in the range between 45-55 shore D. This hardness range provides durability and versatility, making the formulation particularly effective in applications requiring both strength and moderate flexibility.
In an embodiment, the formulation has a water absorption capacity in the range between 0.50-0.80 % for a period in a range between 20-30 hours. Preferably, the water absorption capacity is in the range between 0.55-0.75% for a period in a range between 22-28 hours. Thus, the formulation is ideal for applications requiring moderate moisture resistance without compromising mechanical properties.
In another embodiment, referring to figure 1, an article comprising the thermoplastic resin is disclosed. The thermoplastic resin, incorporating recycled materials and carefully selected plasticizers, is used to produce durable, flexible, and high-performance items. These articles can include everyday consumer goods such as packaging materials, automotive parts, medical devices, or construction components, each benefiting from the resin's improved mechanical strength, processability, and sustainability. By using a combination of recycled thermoplastic materials like PVC, and CPVC, along with primary and secondary plasticizers, the resulting articles are not only cost-effective but also environmentally friendly, helping reduce waste and reliance on virgin raw materials.
In an embodiment, referring to figure 1, a method for preparing a thermoplastic resin formulation from recycled thermoplastic material is disclosed. This method involves a series of steps to combine and process various components to achieve an optimal resin composition.
The recycled thermoplastic material is obtained in the form of particles with sizes 50-200 microns. These particles are then mixed with secondary plasticizers and can be extruded in pellets. They are further used for processing via extrusion, calendaring, and injection molding to obtain one or more articles.
The method begins with selecting a recycled thermoplastic material, as the base material comprising a primary plasticizer in a specified amount, typically within a range of 15 to 55 phr, to enhance the flexibility and processability of the resin. Next, a secondary plasticizer is introduced, often lot-wise, to further adjust the material’s properties and ensure compatibility with other components. The method may also involve adding additives, such as stabilizers, lubricants, or flow agents, to improve thermal stability, reduce friction, and facilitate the moulding or extrusion processes. The ingredients are thoroughly mixed in at least one selected from tumble mixer, rotary drum mixer and batch mixer to create a uniform formulation, ensuring consistent performance across a range of applications.
The recycled thermoplastic material comprising a primary plasticizer is mixed with the secondary plasticizer. The secondary plasticizer penetrates and swells the recycled thermoplastic material. As the system is heated, the secondary plasticizer molecules diffuse into the polymer and weaken the polymer-polymer interactions. The secondary plasticizer molecules act as shields to reduce polymer-polymer interactive forces and prevent the formation of the rigid network. This reduction in intermolecular or van der Waals forces along the polymer chains increases the flexibility, softness, and elongation of the polymer.
The formulation can further be granulated and then moulded in form of an article, including but not limited to insulation for food contact and medical applications, toys and teething products for infants, pneumatic tires, flooring, inflatable products, foams, roofing membranes, food packaging, footwear, coats, sporting gear, jacketing and wires, car undercoating, carpets, pool liners, power filler cables, toys, magnetic cards, hoses, furniture, exterior siding, bottles, mats, coaches, belts, shoes, frames, windows, conveyor belts, garden PVC pipes, agricultural pipes, tubing, vents, air conditioner conduits, drainage pipes, other building, and construction end-use applications and the like.
Examples are set forth below to further illustrate the nature of the invention and the manner of carrying it out. However, the invention should not be considered as being limited to the details thereof.
Examples:
Example 1: Selection of a suitable secondary plasticizer for PVC
Routinely plasticizers formulations employ CPW or DBE owing to their properties and ease of availability. To determine the suitability of one or more nitroxylenes as a secondary plasticizer, 3-nitro-o-xylene was chosen for comparative studies with chlorinated paraffin wax (CPW), and dibenzyl ether (DBE).
Polymer compatibility/stability analysis of 3-nitro-o-xylene samples was conducted using an alkali test following which parameters such as change in hardness (%), weight (%) and dimension (%) were measured on day 7 and day 28 using reference test standards for methods such as IS:15058:2002.
The plasticizer 3-nitro-o-xylene was added lot-wise with continuous stirring until complete adsorption is achieved, resulting in the formation of a blended mass. Throughout the mixing process, adsorption behaviour of the plasticizer was gathered by recording visual changes, including the amount of plasticizer added with notable alterations in the appearance or consistency of the mixture.
It was observed that while the stabilities of 3-nitro-o-xylene, CPW, and DBE composites were comparable on day 7, surprisingly, 3-nitro-o-xylene demonstrated significantly better stability and softness than CPW and DBE under alkaline conditions on day 28.

Table 1: The table 1 illustrates the comparison between the stability of 3-nitro-o-xylene, CPW and DBE when tested significantly for 7 days and 28 days.
Sr. No Parameters Unit 3-nitro-o-xylene Chlorinated paraffin wax (CPW) Dibenzyl ether (DBE)
1 Alkaline Stability Test (7days)
Change in Hardness % 1.02 1.78 2.94
Change in Weight % 1.62 1.59 1.86
Change in Dimension (L*W*T) % No change No change No change
2 Alkaline Stability Test (28 days)
Change in Hardness % 4.08 7.14 7.84
Change in Weight % 3.2 3.32 3.88
Change in Dimension (L*W*T) % No change No change No change

On day 7, all three plasticizers show similar changes in hardness, weight, and dimensions, indicating comparable initial stability. However, after 28 days, 3-nitro-o-xylene exhibits the least change in hardness (4.08%) and weight (3.2%), suggesting it maintains better softness and lower property loss under alkaline conditions. In contrast, CPW and DBE show higher change in hardness and weight, indicating greater brittleness and degradation over time. Further, DBE shows potential leachability, volatile loss and surface migration over time. This highlights that 3-nitro-o-xylene show enhanced performance in long-term stability, low volatility, and weatherability compared to the other plasticizers.
Further, it was noted that 3-nitro-o-xylene shows compatibility with PVC to obtain the blended mass. 3-nitro-o-xylene was tested as a secondary plasticizer for PVC along with another primary plasticizer.

Example 2: Comparative evaluation of 3-nitro-o-xylene, CPW, and DBE as a secondary plasticizer for Recycled PVC
Three samples of recycled PVC was blended with different plasticizers: CPW, DBE, and 3-nitro-o-xylene to assess the suitability of the provided 3-nitro-o-xylene samples as plasticizers for PVC resin to understand the applicability and effectiveness of 3-nitro-o-xylene as a secondary plasticizer for PVC resin in comparison to other commonly used commercially available options.
The granulated formulation samples with 3-nitro-o-xylene, CPW, DBE were rolled into sheets. Thus the 3-nitro-o-xylene - PVC formulation was processed on two roll mills at 170°C to obtain a sheet wherein gap between the rolls was maintained constant for comparing the formulations.
It was observed that the process of sheet formation took longer with DBE compared to CPW and 3-nitro-o-xylene. Subsequent testing using a shore strength A hardness tester indicated that the sheets produced with DBE were harder in texture compared to those made with 3-nitro-o-xylene and CPW.
Example 3: 3-nitro-o-xylene as a secondary plasticizer for recycled PVC
The granulated formulation was obtained for optimization of 3-nitro-o-xylene as a secondary plasticizer for recycled PVC. All the components including PVC resin as a resin/polymer material, dioctyl phthalate (DOP) as a primary plasticizer, either of 3-nitro-o-xylene, CPW, DBE as a secondary plasticizer, lead stearate as a heat stabilizer, and PE wax as a lubricant, was weighed and mixed to create a premix for the subsequent processing of the PVC formulations. The formulation included 35 phr of primary plasticizer, 5 phr of secondary plasticizer, 3 phr of a lead stearate, and 3 phr of PE wax.
A comparative study was conducted between three commercial secondary plasticizers involving DBP and CPW, with 3-nitro-o-xylene. The premixed PVC formulation was then processed or compounded in a Batch Mixer/Torque Rheometer at 170°C to produce a homogeneously compounded PVC mass. The compounded PVC was subsequently ground into granules for further processing. Compression molding was employed to fabricate films from the granulated PVC, with sheets formed at 200°C. Samples were extracted from the sheets for subsequent analyses, such as tensile testing (elongation), tear strength testing, shore hardness assessment, and others (refer table 2 and 3).
Table 2: The table 2 illustrates the comparative data of mechanical properties for the selection of 3-nitro-o-xylene over CPW and DBE as a secondary plasticizer.
Sr. No Parameters Unit 3-nitro-o-xylene Chlorinated paraffin wax (CPW) Dibenzyl ether (DBE)
1 Density at 23 c gm/ml 1.555 1.554 1.5258
2 Vicat softening temperature C 74.3 74.5 73.9
3 Tensile strength Mpa 10 12.6 11.5
4 % of elongation % 160 175 225
5 Water absorption, for 24 hours % 0.62 0.67 0.69
6 Indentation hardness-Shore D Shore D 49 56 51
7 Ash content % 27.7 24.4 24.5
8 Carbon black content % 18.5 17.1 19.6

Table 3: The table 3 illustrates the results for accelerated test
Sr. No Parameters Unit 3-nitro-o-xylene Chlorinated paraffin wax (CPW) Dibenzyl ether (DBE)
1 Accelerated test (for 28 days)
Change in strength % 40 35 43
Change in elongation % 45 37 42.5

The table illustrates the effects of a 28-day accelerated extraction test on material properties exposed to 3-nitro-o-xylene, Chlorinated Paraffin Wax (CPW), and Dibenzyl Ether (DBE). Referring to table 2 and table 3, the increased change in elongation, and lower Indentation hardness-Shore (D) indicates enhanced plasticizing effect of the secondary plasticizer. Specifically, 3--nitro-o-xylene showed enhanced effect in view of properties related to flexibility and softness.
The observed colour difference among the PVC sheets was minimal. Results obtained from the torque rheometer revealed the torque difference and plasticisation time for PVC formulations containing CPW and 3-nitro-o-xylene were nearly equivalent, whereas those with DBP differed. This suggests that the maximum torque required for compounding PVC with DBP is higher compared to CPW and 3-nitro-o-xylene. Consequently, it can be inferred that 3-nitro-o-xylene and CPW confer greater flexibility to the PVC compared to DBP.
Example 4: Comparative analysis of the thermal and plasticizing behaviours of the substances
Fourier-transform infrared spectroscopy (FTIR): Referring to Figure 2 Spectrographs have been included to demonstrate the compatibility analysis using FTIR instruments for the samples. No additional observations or comparisons are mentioned.
Thermogravimetric analysis (TGA): Referring to Figure 4, Thermograms show comparable mass changes at temperatures above 300°C, with initial degradation temperatures up to 250°C being similar across the samples. This suggests similar thermal stability up to this point for all three materials.
Differential scanning calorimetry (DSC): Referring to Figure 3, The thermogram analysis indicates that 3-Nitroxylene (3-Nox) has a greater drop in TG (TG charge) compared to Chlorinated Paraffin Wax (CPW), implying that 3-nitro-o-xylene exhibits better plasticizing properties than CPW. This observation suggests that 3-nitro-o-xylene has superior ability to soften or alter the material’s behaviour under thermal stress, which could enhance performance in specific applications compared to CPW.
In conclusion, the analysis of 3-nitro-o-xylene, DBE, and chlorinated paraffin wax (CPW), and the control material through FTIR (See Figure 2), TGA (See Figure 3), and DSC (See Figure 4) tests reveals valuable insights into their thermal and plasticizing behaviours. The FTIR spectrographs confirm material compatibility without revealing significant differences. TGA results show similar thermal stability up to 250°C, indicating no major discrepancies in the initial degradation temperatures. However, DSC analysis highlights that 3-nitro-o-xylene demonstrates superior plasticizing properties compared to CPW, suggesting it may offer enhanced performance in applications requiring better thermal behaviour and material flexibility.
As a result, through extensive experimentation and analysis of test results, it was observed that the properties exhibited by 3-nitro-o-xylene as a secondary plasticizer are not only comparable but also superior to those of other commercially utilized secondary plasticizers. Based on these conclusive findings and observations, it is determined that 3-nitro-o-xylene can indeed be effectively employed as a secondary plasticizer for recycled PVC and CPVC.
The presently disclosed a plasticizer, a thermoplastic resin formulation and method of preparation may have the following advantageous functionalities over the conventional art:
• Softened, flexible and bendable PVC and CPVC.
• Less plasticization time.
• Reuse of co-products.
• Cost-efficient and environmentally sustainable.
• Increased recyclability and lifecycle of PVC and CPVC based articles.
• Easier to handle plasticized PVC for further processing to end products leading to a huge range of possibilities for new applications.
The foregoing description shall be interpreted as illustrative and not in any limiting sense. A person of ordinary skill in the art would understand that certain modifications would be encompassed within the scope of this disclosure. The embodiments, examples and alternatives of the preceding paragraphs or the description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments unless such features are incompatible.
,CLAIMS:WE CLAIM:
1. A plasticizer for thermoplastic resin formulation, wherein the plasticizer is selected from one or more nitroxylenes.
2. The plasticizer as claimed in claim 1, wherein the one or more nitroxylenes is a secondary plasticizer.
3. The plasticizer as claimed in claim 1, wherein the one or more nitroxylenes is recovered as co-products of industrial processes.
4. The plasticizer as claimed in claim 1, wherein the one or more nitroxylenes is selected from 3-nitro-o-xylene, 4-nitro-o-xylene, 4-nitro-m-xylene, 2-nitro-m-xylene, 5-nitro-m-xylene, 2-nitro-p-xylene or combinations thereof.
5. A thermoplastic resin formulation, comprising:
a recycled thermoplastic material, wherein the recycled thermoplastic material comprises a primary plasticizer present in the amount in the range of 15 to 55 phr of the total weight of the recycled thermoplastic material; and
a secondary plasticizer, wherein the secondary plasticizer is one or more nitroxylenes.
6. The formulation as claimed in claim 5, wherein the recycled thermoplastic material comprises polyvinyl chloride (PVC), and chlorinated polyvinylchloride (CPVC) or combinations thereof.
7. The formulation as claimed in claim 5, wherein the recycled thermoplastic material is present in an amount in the range of 50-80% of the total weight of the formulation.
8. The formulation as claimed in claim 5, wherein the one or more nitroxylenes is selected from 3-nitro-o-xylene, 4-nitro-o-xylene, 4-nitro-m-xylene, 2-nitro-m-xylene, 5-nitro-m-xylene, 2-nitro-p-xylene or combinations thereof.
9. The formulation as claimed in claim 5, wherein the secondary plasticizer is present in an amount in the range of 0.1 to 30 phr the total weight of the recycled thermoplastic material.
10. The formulation as claimed in claim 5, wherein the formulation comprises of one or more additives selected from stabilizers, lubricants, fillers, and swelling agents.
11. The formulation as claimed in claim 5, wherein the formulation has a density in the range between 1.535 to 1.575 gm/ml at a temperature in the range between 20-30°C.
12. The formulation as claimed in claim 5, wherein the formulation has a softening temperature in the range between 65-85°C.
13. The formulation as claimed in claim 5, wherein the formulation has a tensile strength in the range between 5-15Mpa.
14. The formulation as claimed in claim 5, wherein the formulation has a % of elongation in the range between 150-170%.
15. The formulation as claimed in claim 5, wherein the formulation has shore D-hardness in the range between 40-60 shore D.
16. The formulation as claimed in claim 5, wherein the formulation has a water absorption capacity in the range between 0.50-0.80 % for a period in a range between 20-30 hours.
17. An article comprising the thermoplastic resin formulation of claim 5.

Dated this 2nd Day of December 2024.

DEEPAK KUNDLIK PAWAR
IN/PA-2052
AGENT FOR THE APPLICANT