Description:TECHNICAL FIELD
The present invention relates to biopolyol polymers derived from natural oils, specifically castor oil, and their associated methods and applications. The invention focuses on bio-based polyurethane foam created by synthesizing high molecular weight biopolyol polymers derived from natural oils.

OBJECT OF THE INVENTION
The invention relates to biopolyol polymers and biopolyurethane foam derived from the said biopolyol polymers. The biopolyol polymers are derived from naturally occurring castor oil extracted from plant sources which are linked with a crosslinker that increases molecular weight and are further alkoxylated by alkylene oxides.
These biopolyols are produced through a cross-linking process that involves esterification, followed by alkoxylation, using specific catalysts under controlled conditions. The resulting biopolyols are used to manufacture polyurethane foams with a high bio-content, comparable in performance to those made from synthetic polyols derived from petroleum sources.
Synthetic polyols have been widely used to produce a variety of polyurethanes with flexible properties tailored to specific needs. However, their primary drawback is that they are derived from petrochemicals, a diminishing and non-renewable resource. In many applications, efforts are underway to replace synthetic polyols with bio-based alternatives. Unfortunately, bio-based polyols often have limitations, such as predefined molecular weights and functionalities, which restrict their ability to produce polyurethanes with the desired properties.
The present invention attempts a novel approach to obtain advanced biopolyols derived from natural biological sources, designed to overcome these limitations. This novel biopolyol features a high bio-content and enhanced functionalities achieved through cross-linking of natural polyols and subsequent chain elongation. With a sufficiently high molecular weight and flexible polymer chains, this polyol is ideal for producing bio-based polyurethane foams with high bio-content. These foams are particularly suitable for applications such as mattress manufacturing. The structural design of the biological polyol ensures a significantly high bio content, and as a result, the polyurethane foam produced from this composition demonstrates substantially improved bio-content as well.

BACKGROUND TECHNOLOGY
Previous art, such as U.S. Patent 1933697 and German Patent 479985, has mentioned polyesters derived from castor oil and various dibasic acids, primarily used as softening agents. However, these compounds lacked the necessary molecular functionality to react with isocyanates, making them unsuitable for polyurethane production. This invention addresses that limitation by controlling the esterification of castor oil with dibasic acids to predominantly form dimers. These dimers are subsequently treated with ethylene oxide and propylene oxide in the presence of double metal cyanide (DMC) catalysts, significantly increasing the molecular weight and producing a high molecular weight functional polyol.
The resulting polyol, derived from sustainable natural sources, offers numerous advantages, including enhanced flexibility. This makes it particularly suitable for producing polyurethane foams for a variety of commercial applications, such as mattresses, insulation materials, and more.
Polyurethane polyol derived from biological sources have emerged as very important class of polyols for mattress and related applications due to their versatility and performance. The conventional commercial polyurethane polyols are almost exclusively derived from petrochemical resources accounting for their high carbon foot-print, as well as their increasingly high cost.
As reviewed in Desroches, M et al.,( Polym. Rev. 2012, 52 (1), 38- 79) biobased polyols for polyurethanes are primarily derived from vegetable oils through various synthetic routes including epoxidation of olefinic functionalities, reactions involving double bonds of triglycerides, and utilization of carbonyl groups, with the review also covering commercial biobased polyols and their industrial synthesis as detailed in patent literature.
Maisonneuve, L et al., (OCL 2016, 23(5) D508) states about preparation of different vegetable oil-based polyurethanes via the isocyanate/alcohol route.
Fridrihsone, A et al. (J. Cleaner Prod. 2020, 266, 121403) evaluates a cradle-to-gate environmental impact of rapeseed oil, being the most dominant oil-bearing crop in Europe, based polyols developed at the LSIWC using two different routes – amidization with diethanolamine (DEA) and transesterification with triethanolamine (TEA). Developed rapeseed oil polyols have been used for the development of rigid PU foams for thermal insulation.
Different renewable sources have been explored for the preparation of biobased polyols including vegetable oils, microalgae, lignocellulose such as wood or annual crops, and polysaccharides. Biomass is rich with a wide range of chemical structures, from which different types of polyols can be prepared. Thus, lipids have been traditionally explored as a source to produce polyester polyols. Polysaccharides have been more employed for the preparation of polyether polyols, and lignocellulose has been investigated for the preparation of aromatic polyols. Table 1-2 highlights that among various biobased materials, polyols derived from vegetable oils have emerged as the most favored in both academic research and industrial applications due to their sustainable properties and performance.

Table 1. Cashew Nutshell Liquid (CNSL)-Based Polyols Available on the Market in 2021
Company Product Bio Content(%) OH Value (mg KOH/g) F* Application
Cardolite NX 88-93 175-200 3.3-4.4 CASE#
GX 59 to 95 175 to 475 3 to 4.4 Rigid PU@
ExaPhen XFN 73 to 99 180 to 550 3 to 8 CASE, Rigid PU
Palmer International Perrenol NA — 430 to 470 3 to 4 Rigid PU (Flame retardant)
# Coatings, adhesives, sealants and elastomers
@ polyurethanes

Table 2. Main Natural oil polyol (NOP) producers and the family of products in the catalogue
Company Product NOP Bio Content (%) OH Value (mg KOH/g) Fs Application

Alberdingk Boley Albodur Castor oil 100 NA NA CASE
BASF Sovermol Soybean oil 65 to 100 145 to 460 2 to 3.5 All
Cargill BiOH Soybean oil NA 40 to 68 0.8 to 2 CASE
98 70 to 110 1.3 to 2 Flexible PU
Croda Priplast Various 82 to 86 56 to 71 NA CASE
Eagle Chemicals T series Castor oil 100 102 to 168 NA Flexible PU
Emery Oleochemicals Emerox Palm oil 69 to 99 56 to 370 2 to 3.7 CASE, Flexible PU
45 to 99 230 to 370 1.1 CASE, Flexible PU
Hokoku Castor Oil Polyol Castor oil NA NA 2 to 5 CASE, Rigid PU
Itoh Oil Chemicals Uric Castor oil NA 90 to 340 1 to 3 CASE, Rigid PU
NivaPol Polem A Castor oil 47 to 99 160 to 340 4.7 to 8.2 Rigid PU
40 to 66 130 to 350 5.8 to 10.9 Rigid PU
Oléon Radia Various 100 50 to 395 2.3 to 2.6 CASE, Rigid PU
Polylabs BioPolyol Rapeseed oil 83 360 to 410 1.3 to 2.2 Rigid PU, Flexible PU
Stahl Relca Bio Rapeseed oil, Tall oil 70 to 80 260 to 280 1.1 Rigid PU
Vertellus Polycin Castor oil 100 52 to 160 2 to 2.7 CASE, Flexible PU
Source: https://pubs.acs.org/doi/10.1021/acssuschemeng.1c02361

Due to eventual possibility of availability and supply of petroleum raw materials, mainly imported leading the higher losses in foreign exchange as well as diversion of these petroleum resources to non-energy applications and the problems of soaring petrochemical prices, the need of developing an alternative source and that too bio-based have become increasingly urgent. In addition, a large amount of pollutants are also produced during the production, use, and disposal of petrochemical products, causing many environmental problems. India produces around 80% of the world's castor oil, with 18% coming from the Kutch region. The Kutch is a dry, treeless landscape with unreliable rains, but the castor plant is hardy and can be cultivated there. The castor plant is vital to small family shareholders in the Kutch. Castor oil presents a good candidate as a raw material for the production of bio polyols due to this reason. The castor oil production in no way results in taking away land meant for food production and is a renewable plant source for long term replacement of depleting petroleum reserves

SUMMARY
The invention relates to a biopolyol polymer and a biopolyurethane foam material derived from the said biopolyl polymer. The biopolyol polymer is derived from naturally occurring castor oil extracted from plant sources linking it with a crosslinker that increases molecular weight and alkoxylation by alkylene oxides.
The biopolyurethane foams are comparable to those obtained from petroleum-derived synthetic polyols, but they are made from a naturally occurring castor oil derivative that has a specified structure and high molecular weight, sourced from renewable plant materials.
The biopolyol polymer which contains a derivative of naturally occurring castor oil extracted from plant sources is synthesized by following steps:
a. First step consists of linking naturally occurring castor oils with crosslinking moieties such as diacids, anhydrides, diisocyanates or combinations thereof to increase molecular weight.
b. alkoxylation of the above synthesized product using alkoxides such as ethylene oxide and/or propylene oxide and a catalyst like double metal catalyst
The biopolyol polymer involves converting a natural polyol into a dimer, which is then reacted with alkoxides such as, but not limited to, ethylene oxide and/or propylene oxide in second step of synthesis.
The biopolyol polymer as stated above can be used in manufacture of foam which could be only achieved by using synthetic petroleum based polyols. The foam prepared using the said biopolyol polymer combination is prepared using common techniques for the manufacturing of foam.
The foam prepared using the biopolyol polymer combination has high natural replenishable content from the bio-based polyol made from biological raw materials directly replacing the synthetic polyols without loss of properties.

DETAILED DESCRIPTION
Castor oil cannot be directly added to the regular polyol in the polyurethane foam production process due to its low molecular weight, which results in foams with reduced compression set values. Additionally, the reactivity of the hydroxyl groups attached to the castor oil and the structure of the castor oil molecule contribute to the production of low-quality polyurethane foams. To address these issues, castor oil molecules must be chemically linked together and then alkoxylated to form a high molecular weight biopolyol polymer. This modified structure can then be converted into polyurethane foams when reacted with isocyanates, such as toluene diisocyanate, using standard polyurethane foam manufacturing processes for applications like mattresses.
The biopolyol developed through this modification process not only produces usable products like polyurethane foam mattresses but is also compatible with current foaming technologies and capable of sustaining the demands of both continuous and discontinuous foam production processes.
Our unique process for modifying castor oil results in a high bio-content polyol with increased molecular weight and functionality. This innovation leads to a product with reduced petroleum content and enhanced mechanical properties.
The specific embodiments described herein have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

EXAMPLES
Example 1a
1860 g (2mol) of castor oil is added to a reaction vessel. 146 g (1 mol) of adipic add is further added to the vessel. The reaction is started and as the reaction proceeded the acid value was measured. Tetrabutyl-n-titanate (100 ppm) was used as a catalyst. The reaction was stopped at an acid value of lower than 5 mg KOH/g and an hydroxyl value between 93 - 99 mg KOH/g, with a molecular weight of 1970 g/mol. The yield is 98.2%. This adduct was then alkoxylated with a 90:10 mixture of 1430 g alkoxides (propylene oxide:ethylene oxide), using a DMC catalyst.
The hydroxyl value of the polyol is 56 mg KOH/g and the corresponding molecular weight is 3400 g/mol. This polyol was used to make flexible foams using a regular foaming formulation.

Stage 1a

Example 1b
1860 g (2mol) of castor oil is added to a reaction vessel. 102 g (0.7mol) of adipic acid is further added to the vessel. The reaction is started and as the reaction preceded the acid value was measured. Tetrabutyl-n-titanate (100 ppm) was used as a catalyst. The reaction was stopped at an acid value of Lower than 5 mg KOH/g and an hydroxyl value between 113 - 119 mg KOH/g, with a molecular weight of 1926 g/mol. The yield is 98.2 %. This adduct was then alkoxylated with a 90:10 mixture of 2076 g alkoxides (propylene oxide:ethylene oxide), using a DMC catalyst. The hydroxyl value of the polyol is 56 mg KOH/g and the corresponding molecular weight is 4000 g/mol. This polyol was used to make flexible foams using a regular foaming formulation.
Stage 1b

Example 2a

1860 g (2 mol) of castor oil is added to a reaction vessel. 148 g (1 mol) of phthalic anhydride is further added to the vessel. The reaction is started and as the reaction proceeded the acid value was measured. Tetrabutyl-n-titanate (100 ppm) was used as a catalyst. The reaction was stopped at an acid value of lower than 5 mg KOH/g and a hydroxyl value between 92-98 mg KOH/g, with a molecular weight of 1990 g/mol. The yield is 99.1 %. This adduct was then alkoxylated with a 90:10 mixture of 1410 g alkoxides (propylene oxide:ethylene oxide), using a DMC catalyst. The hydroxyl value of the polyol is 56 mg KOH/g and the corresponding molecular weight is 3400 g/mol. This polyol was used to make flexible foams using a regular foaming formulation. (The presence of predominately diester and further alkoxylation is confirmed by FT-IR and 1H NMR)

Example 2b

1860 g (2 mol) of castor oil is added to a reaction vessel. 104 g (0.7 mol) of phthalic anhydride is further added to the vessel. The reaction is started and as the reaction proceeded the add value was measured. Tetrabutyl-n-titanate (100 ppm) was used as a catalyst. The reaction was stopped at an acid value of lower than 5 mg KOH/g and a hydroxyl value between 112- 118 mg KOH/g, with a molecular weight of 1951 g/mol. The yield is 99.1%. This adduct was then alkoxylated with a 90:10 mixture of 2049 g alkoxides (propylene oxide:ethylene oxide), using a DMC catalyst. The hydroxyl value of the polyol is 56 mg KOH/g and the corresponding molecular weight is 4000 g/mol. This polyol was used to make flexible foams using a regular foaming formulation. The characterization of the said adduct has been thoroughly conducted, with the corresponding illustrations provided in Drawings 1 to 3 for reference.

Example 3a
1860 g (2 mol) of castor oil is added to a reaction vessel. 174 g (1 mol) of toluenediisocyante is further added to the vessel. The reaction is started and as the reaction proceeded the NCO % was measured. The reaction was stopped at an NCO % value of zero and a hydroxyl value between 92-98 mg KOH/g, with a molecular weight of 2034 g/mol. The yield was 99.6 %. This adduct was then alkoxylated with a 90:10 mixture of 1366 g alkoxides (propylene oxide:ethylene oxide), using a DMC catalyst. The hydroxyl value of the polyol was 56 mg KOH/g and the corresponding molecular weight is 3400 g/mol. This polyol was used to make flexible foams using a regular foaming formulation.
Example 3b
1860 g (2 mol) of castor oil is added to a reaction vessel. 121 g (0.7 mol) of phthalic anhydride is further added to the vessel. The reaction was started and as the reaction proceeded the NCO % was measured. The reaction was stopped at an NCO % value of zero and a hydroxyl value between 112- 115 mg KOH/g, with a molecular weight of 1982 g/mol. The yield was 99.6%. This adduct was then alkoxylated with a 90:10 mixture of 2018 g alkoxides (propylene oxide:ethylene oxide), using a DMC catalyst. The hydroxyl value of the polyol is 56 mg KOH/g and the corresponding molecular weight is 4000 g/mol. This polyol was used to make flexible foams using a regular foaming formulation.

The properties of the biopolyol polymer, as synthesized in the examples above, are summarized in Table 4.

The analysis for 1H NMR for castor oil and the adduct is given below.

Table 3: 1H NMR analysis of castor oil and castor oil phthalic anhydride adduct
Carbons Chemical shifts of protons attached to the carbons of castor oil Chemical shift of protons attached to the carbons of castor oil-phthalic anhydride adduct
Methylene group of castor acid attached to carbonyl group C2 2.3 ppm, 2.2
Methylene group of castor acid C3 1.6 ppm, 1.77
Methylene group of castor acid attached to carbonyl group C4, C5, C5, C6, C7 1.3 ppm, 17.54/9 1.3 ppm, 47.4
Methine group of double bond C8 2.05 ppm, 2.39
Methine group of double bond C9 5.6 ppm, 0.97 5.5 ppm, 6.69
Methylene group of castor acid C10 5.4 ppm, 1.29
Methylene group of castor acid C11 2.2 ppm,2.00
Methane group attached to the hydroxyl group C12 3.6 ppm,0.99 3.6 ppm, 3.8 ppm, 1.1 and 0.58
Methylene group of castor acid C13 1.3 ppm,17.54/9
Methylene group of castor acid C14, C15, C16, C17 1.3 ppm, 17.54/9 1.3 ppm, 47.4
End methyl group of the castor acid C18 0.88 ppm3.35 0.88 ppm, 8.06
OH 1.6 ppm, 1.77
Glycerol unit GA 4.2 ppm, 0.76 4.3 ppm, 3.73
Glycerol unit GB 4.3 ppm, 0.71
Glycerol unit GC 5.22 ppm,0.39 4.9 ppm, 1.00
Phthalic anhydride, 4 protons are present i0n the acid and there is presence of 1 phthalic acid for 2 molecules of castor acid 7.6 ppm, 1.81

Table 4: Finished biopolyol polymer properties

Example Castor oil-crosslinker Castor oil-crosslinker ratio Functionality Molecular weight in first step (g/mol} OHv• in first step (mg KOH/g}. Molecular weight In the final polyol after alkoxylation (g/mol) Bio % in the final polyol (approx. in %} OHv after the final step (mg KOH/g)
1a Castor oil- adipic acid 2-1 3.4 1970 97 3400 54 56
1b 2-0.7 4 1926 116 4000 45 56
2a Castor oil- phthalic anhydride 2-1 3.4 1990 96 3400 54 56
2b 2-0.7 4 1951 115 4000 45 56
3a Castor oil-TDI 2-1 3.4 2034 94 3400 55 56
3b 2-0.7 4 1982 113 4000 45 56

The formula used for determination of molecular weight is:
Molecular Weight = (56100 x functionality/OHv)
(ref: Mihaillonescu, Chemistry and Technology of Polyols and Polyurethanes, znct Edition, pg 44, Vol 1, Smithers Rapra.)

Example 4
The foaming is carried out using the regular foaming formulations with toluene diisocyanate.

Table 5: Typical foam formulation
Bio Polyol Biopolyol polymer made as per description made herein Manufacturer 90
Polymer polyol A standard polymer polyol with solids content of around 45 – 49 % like Arcol HS 200 Covestro 10
Niax A1 Catalyst promoting the basic chemical reactions between polyol and isocyanate and water and isocyanate Momentive 0.0425
Niax A33 Catalyst promoting gelling reactions between polyol and isocyanate Momentive 0.1625
L618 Silicone for providing foam stability from Momentive 1.4
Water For inducing blowing reaction - 3.35
T9 Stannous octoate catalyst for gelling Evonik 0.6
TDI (Index: 106) Toluene diisocynate Gujarat Narmada Valley Fertilizers & Chemicals Limited (GNFC) 43.7

The properties obtained on the foam made with bio polyol

Table 6: Foam analysis report

Material Biopolyol polymer based Formulation Synthetic Polyol based Formulation
Synthetic polyol Dow Voranol 8010 0 90
Bio Polyol 90 0
Polymer polyol 10 10
Niax Al 0.03 0.03
Niax A33 0.1 0.1
Niax L618 1.25 1.25
Water 2.8 2.8
T9 0.75 0.75
TDI(Index :106) 38.1 38.1
Bio content in foam (%) 34.7 0
Foam Properties Biopolyol Formulation Synthetic Polyol Formulation
Density (kg/m3) 33 34
Hardness at 40%- (N) 146 172.65
Support Factor 1.99 1.9
Resiliency % 38 41
Tensile strength kg/cm2

Tensile Strength 0.718 0.851
Elongation (%} 133.71 187
Compression Set (%) 7.4 4.17
Bio content (%) 34.7 0 , Claims:We Claim,
1. A biopolyol polymer and polyurethane foam derived from the said biopolyols comparable to those obtained from petroleum derived synthetic polyols comprising of a derivative of naturally occurring castor oil extracted from plant sources characterized by a specified structure and enhanced molecular weight.
2. The biopolyol polymer as claimed in claim 1 wherein the biopolyol polymer which contains a derivative of naturally occurring castor oil extracted from plant sources is synthesized by following steps:
a. Linking naturally occurring castor oil extracted from plant sources with crosslinking moieties that increases molecular weight such as diacids, anhydrides, diisocyanates or combinations thereof;
b. Alkoxylation of the above synthesized product using alkoxides such as ethylene oxide and/or propylene oxide and catalyst such as double metal catalyst.
3. The biopolyol polymer as claimed in claim 1 wherein the natural polyol is dimeric.
4. The biopolyol polymer as claimed in claim 1 can be used in manufacture of foam with properties which could be only achieved by using synthetic petroleum based polyols.
5. The alkoxides as claimed in claim 2 are but not limited to ethylene oxide and/or propylene oxide.
6. The foam prepared using the said biopolyol polymer as claimed in claim 4 is prepared using common techniques for the manufacturing of foam with high bio-content.
7. The foam prepared using the said biopolyol polymer as claimed in claim 4, has high natural replenishable content from the bio-based polyol made from biological raw materials directly replacing the petroleum based synthetic polyols without loss of properties