# Bio-based polyols & biopolyurethanes

Renewable hydroxyl-functional building blocks from vegetable oils, lignin and cashew nutshell liquid that replace petrochemical polyols and isocyanates in flexible foams, coatings, TPU and elastomers — closing the carbon loop of a >$90 bn polyurethane market.

Source: https://en.bioecon.ru/technology/bio-based-polyols-biopolyurethanes/
Updated: 2026-08-18



## Overview and value chain

Markers: [EC: USDA BioPreferred + EU REACH/ECHA isocyanate restrictions + ISCC PLUS Mass Balance | OECD: Bio-based materials, Industrial biotechnology | Regulator: EPA (USA), REACH (EU)]

Bio-based polyols are hydroxyl-functional intermediates synthesised by
introducing –OH groups into the triglycerides of vegetable oils (soybean,
castor, rapeseed, linseed) or into alternative aromatic feedstocks (lignin,
cashew nutshell liquid). Reacted with (bio-)isocyanates, they yield
biopolyurethanes — flexible and rigid foams, thermoplastic polyurethanes (TPU),
coatings, adhesives and elastomers — that are 30–100% bio-derived versus their
petrochemical analogues. Natural-oil polyol lines such as BASF's Sovermol
typically carry 80–100% bio-content, while bio-PDO chain extenders cut
cradle-to-gate greenhouse-gas emissions by up to 86% versus fossil PDO. The
global polyurethane market is projected to exceed $90 bn through 2026, and the
US soy-polyol segment alone is forecast to grow from $487.6 M (2026) to
$1,033 M (2035) at an 8.70% CAGR — so even partial bio-content substitution
moves multi-billion-dollar procurement volumes. Hydroxyl values are tuned to
50–240 mg KOH/g to match flexible-foam, rigid-insulation or coating duties.

The key directions of bio-based polyols and biopolyurethanes are:
1. **Vegetable-oil polyols (Soybean / Castor / Rapeseed / UCO Polyols):** epoxidation of unsaturated fatty acids followed by acid-catalysed ring-opening with alcohols or diols — the workhorse route, supplying >80%-bio-content polyols for flexible foams, mattresses and automotive seating.
2. **Bio-based diisocyanates (Bio-PDI):** precision fermentation of lysine to 1,5-pentanediamine, then phosgene-free conversion to pentamethylene diisocyanate — the breakthrough that removes the last 100%-petrochemical half of a polyurethane, pioneered at 50 kt/yr scale in China.
3. **Non-isocyanate polyurethanes (NIPU):** reaction of cyclic carbonates (from epoxidised oils + captured CO2) with bio-based diamines, fully eliminating toxic phosgene and isocyanate chemistry — the EU-led response to ECHA isocyanate restrictions.
4. **Lignin & CNSL polyols (Aromatic Bio-Polyols):** partial hydrolysis of kraft/organosolv lignin or ethoxylation of cardanol from cashew nutshell liquid, delivering rigid aromatic backbones with inherent flame resistance and extreme hydrophobicity for marine coatings.

### Sectoral value chain

```
[vegetable oils / lignin / CNSL] ──> [epoxidation + ring-opening] ──> [bio-polyols (B2B)]
                                              │
                                   (OH value 50–240 mg KOH/g)
                                              │
                                              ▼
[bio-PU foam / TPU / coating] <─── [reaction with bio-PDI / NIPU] <─────┘
```

### Value chain levels

| Level | Description | Key inputs/outputs |
|:---|:---|:---|
| **Feedstock origination** | soybean, castor, rapeseed, UCO, lignin, CNSL sourcing | **In:** oilseeds, castor beans, waste oils.<br>**Out:** refined triglycerides. |
| **Epoxidation** | peracid oxidation of C=C bonds to oxirane rings | **In:** vegetable oil, H2O2, formic acid, resin.<br>**Out:** epoxidised oil. |
| **Ring-opening / polyol synthesis** | acid-catalysed ring-opening to install –OH groups | **In:** epoxide, alcohol/diol, catalyst.<br>**Out:** bio-polyol (set OH value). |
| **Bio-isocyanate / NIPU precursor** | fermented pentanediamine → PDI, or cyclic carbonate | **In:** lysine, sugars, CO2, diamines.<br>**Out:** bio-PDI / cyclic carbonate. |
| **PU reaction / foaming** | high-pressure mix of polyol + isocyanate, or NIPU | **In:** bio-polyol, bio-PDI, catalysts.<br>**Out:** foam / elastomer / TPU. |
| **Certification & QA** | ASTM D6866 C14, ISCC PLUS mass balance, CertiPUR | **In:** cured articles, test rigs.<br>**Out:** certified bio-PU product. |

Cross-cutting technologies of the sector:
- **Epoxidation + ring-opening chemistry (Epoxidation + Ring-Opening):** peracid generation in situ from H2O2 and carboxylic acid over a cation-exchange resin, followed by acid-catalysed oxirane opening — controls OH value and functionality.
- **Bio-PDO fermentation (Bio-PDO Fermentation):** precision fermentation of corn-dextrose glucose to 1,3-propanediol (Susterra/Zemea), used as a chain extender and polytrimethylene ether glycol (PO3G) polyol.
- **ISCC PLUS mass balance (ISCC PLUS Mass Balance):** certified book-and-claim accounting that allocates renewable feedstock to bio-attributed PU grades (Desmopan EC, Sovermol) in existing asset bases.

---

## US

The US anchors the soy-polyol segment, leveraging the Midwest soybean crushing belt and federal procurement preference under USDA BioPreferred.

### soy-polyol leadership, bio-PDO chain extenders, automotive + bedding demand
- **Cargill BiOH polyols:** epoxidised/hydroxylated soybean-oil polyols sold into mattress and automotive flexible foam (Room & Board upholstery, Ford seating), replacing a portion of petrochemical polyol.
- **CovationBio PDO (ex–DuPont Tate & Lyle):** 77,000 t/yr bio-PDO from regenerative Midwestern corn, processed in Loudon, TN — 86% lower carbon footprint (4.41 kg CO2 eq) than fossil PDO, 20 years in market.
- **US soy-polyol market:** $487.6 M in 2026, forecast to $1,033 M by 2035 at 8.70% CAGR, with EPA TSCA Section 5 pathways and USDA BioPreferred accelerating reformulation.

---

## CN

China is the global hub for bio-based diisocyanates, converting castor oil and fermented diamines into the world's first fully bio-based PU elastomers and foams.

### bio-PDI breakthrough, castor-oil mega-plants, state green-chemistry subsidies
- **Cathay Biotech (688065.SH):** precision-ferments lysine to bio-based pentanediamine (50 kt/yr, the PDI precursor) and long-chain dicarboxylic acids (115 kt/yr, DC10–DC18), plus bio-polyamides (100 kt/yr); 2025 Q3 revenue RMB 2.545 bn (+14.9%), 494 patents.
- **Castor-oil polyol plants:** large Zhejiang and Jiangsu facilities modify castor oil into polyols for the global sustainable-footwear sole supply chain.
- **State subsidies:** green-chemistry projects subsidised under national carbon-intensity-of-industry programmes, with GB indoor-air-quality standards tightening purity specs.

---

## EU

The EU leads on non-isocyanate polyurethanes (NIPU) and circular feedstocks, driven by ECHA restrictions on toxic isocyanates in construction foams and coatings.

### NIPU R&D, UCO/animal-fat feedstocks, ISCC PLUS + OEKO-TEX certification
- **Covestro bio-aniline + MDI:** the €8.4 M EU-funded Bio4PURConti project (June 2026) targets the world's first continuous bio-based aniline process for MDI, cutting up to ~20 Mt/yr of global fossil-aniline CO2; Desmopan EC TPU carries up to 60% biomass carbon (>20% lower footprint).
- **BASF Sovermol polyols:** natural-oil polyols (rapeseed/castor) at 80–100% bio-content for solvent-free industrial, marine and wind-power coatings.
- **Circular feedstocks:** used cooking oil (UCO) and technical animal fats epoxidised into polyols, avoiding food-vs-land competition; OEKO-TEX Standard 100 and CertiPUR govern eco-leather and furniture-foam emissions.

---

## Leading companies and research institutes

| Company / Institute | Country | Key products / platforms | Tech features | Status 2026 |
|:---|:---|:---|:---|:---|
| **Cargill** | 🇺🇸 USA | *BiOH soy polyols* | epoxidised soybean oil, flexible foam | Commercial |
| **CovationBio PDO** | 🇺🇸 USA | *Susterra / Zemea bio-PDO* | 77,000 t/yr, 86% lower CO2 | Commercial |
| **Covestro** | 🇩🇪 Germany | *Desmopan EC bio-TPU, bio-aniline MDI* | up to 60% biomass, Bio4PURConti | Commercial |
| **BASF** | 🇩🇪 Germany | *Sovermol natural-oil polyols* | 80–100% bio-content, castor/rapeseed | Commercial |
| **Cathay Biotech** | 🇨🇳 China | *bio-pentanediamine, long-chain diacids* | 50 kt/yr PDI precursor, 688065.SH | Commercial |
| **Jayant Agro-Organics** | 🇮🇳 India | *castor bio-polyols (Vithal Castor Polyols)* | 90% VCPL stake (2026), NSE:JAYAGROGN | Commercial |

---

## Tech stack and innovations

The stack couples oleochemical polyol synthesis with a new generation of bio-based hard-segment monomers and non-isocyanate routes.

1. **Epoxidation + ring-opening route (Epoxidation + Ring-Opening):**
   - peracetic/formic acid generated in situ from 50% H2O2 over a cation-exchange resin at 50–70°C opens C=C bonds into oxiranes.
   - ring-opening with methanol gives flexible, low-functionality polyols; ethylene glycol or glycerol raises functionality for rigid foams — OH value targeted to 150 mg KOH/g.
2. **Bio-PDO and bio-PDI hard segments (Bio-PDO / Bio-PDI):**
   - corn-dextrose fermentation to 1,3-propanediol (PO3G polyol / chain extender), and lysine fermentation to 1,5-pentanediamine converted to pentamethylene diisocyanate.
   - case: Cathay Biotech's 50 kt/yr pentanediamine enables 100%-bio-derived PU elastomers; CovationBio PDO cuts GHG 69% and non-renewable energy 60%.
3. **Non-isocyanate polyurethanes (NIPU):**
   - CO2-added cyclic carbonates from epoxidised oils react with bio-based diamines, yielding hydroxy-PU with no phosgene or free isocyanate.
   - residual –OH groups improve adhesion to metal and glass, suiting EU construction and coating uses under ECHA limits.

---

## Value chains and production pipelines

### Industrial pipeline of soy-polyol-derived bio-PU flexible foam (ASTM D3574 / DIN EN 1024)

```
┌───────────────────────────┐      ┌───────────────────────────┐
│ 1. Oil purification & QC  │ ───> │ 2. Epoxidation            │
└───────────────────────────┘      └───────────────────────────┘
                                                 │
                                                 ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 4. Ring-opening → polyol  │ <─── │ 3. Wash, neutralise, dry  │
└───────────────────────────┘      └───────────────────────────┘
              │
              ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 5. A-component + foaming  │ ───> │ 6. Curing + QA/QC         │
└───────────────────────────┘      └───────────────────────────┘
```

#### Stage 1: Oil purification and input QC
Soybean oil is filtered and bleached with activated clay; the iodine value must exceed 120 g I2/100 g (unsaturation) and the acid value stay below 1 mg KOH/g to protect downstream catalysts.

#### Stage 2: Epoxidation of triglycerides
Oil, formic acid and a cation-exchange resin are charged; 50% hydrogen peroxide is dosed over 3–4 h at 60°C with jacket cooling — the exotherm is held below 85°C to avoid gel-forming polymerisation.

#### Stage 3: Wash, neutralisation and vacuum drying
The resin is filtered out, the epoxidised oil is washed with deionised water and neutralised, then vacuum-dried at 90°C / 50 mbar to water content below 0.05%.

#### Stage 4: Ring-opening to polyol
The epoxide is reacted with methanol or ethylene glycol over phosphoric acid at 120°C for 4 h; excess alcohol is vacuum-stripped and the polyol is tuned to a hydroxyl value of ~150 mg KOH/g.

#### Stage 5: A-component preparation and foaming
The bio-polyol is blended with water (blowing agent) and amine catalyst, then mixed with bio-PDI isocyanate in a 150-bar high-pressure mix head and dispensed into a 50°C mould — start time 10–15 s, gel time 40–60 s.

#### Stage 6: Curing and QA/QC
The moulded foam is demoulded after 5 min and cured 24 h at room temperature; ASTM D3574 covers density, tensile strength and compression set, and fluctuation-chamber testing confirms no residual amine or isocyanate emissions before the bio-PU article ships.