C20041
Flexible PU hardener for PU-foam primers (C20041)
The alternative (flexible) hardener for the PPS400xx series of coloured PU primers for PU foam and MDF (PPS40040 white, PPS40041 cream, PPS40042 yellow, PPS40043 walnut, PPS40044 light walnut, PPS40045 mahogany, PPS40090 black). Per the dealer note, primer cured with C20041 gives a more flexible film and better adhesion to the substrate than with the standard C20040; it's recommended for flexible parts and 'difficult' PU foam, and it dries slower. The 2019 catalogue lists it alongside C20040 at the same ratio — 20 % by weight. There's no data sheet, no maker's web page and no dealer listing, so the hardener's own specs (solids, isocyanate type, pack sizes) are unpublished.
- second component of the PPS400xx coloured PU primers for PU foam and MDF, in place of C20040
- flexible and thin PU-foam parts (mouldings, frame profiles, bendable decor)
- 'difficult' PU foam where primer on the standard hardener doesn't stick well
Ask about C20041
Answers are based on the C20041 data and the products it mixes with.
Mixing matrix
- % by weight: 20 %catalog% by volume: 30 %recommended
Flexible PU-foam parts, 'difficult' foam, poor primer adhesion on the standard hardener.
Fixed ratio, by weight. It replaces C20040 (or PC20042/PC20 per the current PPS40 page) — don't add it on top.
- S50Thinner% by weight: 20–25 %catalog% by volume: 40–50 %dealer
Standard thinner (normal evaporation).
Thinner amount is set by the primer, not the hardener.
- S50Thinner% by weight: 30 %recommended
The 'Finishing PU-foam products' schedule with the flexible hardener instead of C20040.
- S80Thinner% by weight: 20–30 %recommended
Only in heat above ~25 °C.
Slow hardener plus slow thinner drags drying out further — prefer S50.
- % by weight: C20040 20 % (2019 catalogue; official PPU schedule); PC20042 20 wt %/30 vol %, PC20 25 wt %/35 vol % (official PPS40 page)official
Ordinary rigid parts — faster drying, better sanding.
Alternatives — don't blend with C20041.
| Role | Material | % by weight | % by volume | When |
|---|---|---|---|---|
| base | PPS40040 / PPS40041 / PPS40042 / PPS40043 / PPS40044 / PPS40045 / PPS40090 | 20 %catalog | 30 %recommended | Flexible PU-foam parts, 'difficult' foam, poor primer adhesion on the standard hardener.Fixed ratio, by weight. It replaces C20040 (or PC20042/PC20 per the current PPS40 page) — don't add it on top. |
| Thinner | S50 | 20–25 %catalog | 40–50 %dealer | Standard thinner (normal evaporation).Thinner amount is set by the primer, not the hardener. |
| Thinner | S50 | 30 %recommended | — | The 'Finishing PU-foam products' schedule with the flexible hardener instead of C20040. |
| Thinner | S80 | 20–30 %recommended | — | Only in heat above ~25 °C.Slow hardener plus slow thinner drags drying out further — prefer S50. |
| hardener_alternative | C20040 / PC20042 / PC20 | C20040 20 % (2019 catalogue; official PPU schedule); PC20042 20 wt %/30 vol %, PC20 25 wt %/35 vol % (official PPS40 page)official | — | Ordinary rigid parts — faster drying, better sanding.Alternatives — don't blend with C20041. |
Percentages are per 100 parts of component A.
Characteristics
- Chemistry
- polyisocyanate hardener for 2K PU, flexible grade — exact type (aromatic/aliphatic) not publishedrecommended
- Elasticity
- higher than with the standard hardener C20040dealer
- Adhesion
- better adhesion to the substrate (PU foam) than with C20040dealer
- Reactivity
- slower drying than with C20040dealer
- Pot life
- 3 hdealer
- Drying · Touch-dry
- 30 mindealer
- Drying · Touch dry with C20041 (min)
- 40–60 minrecommended
- Drying · Full cure
- 6 hdealer
- Drying · Sanding (h)
- 3–4dealer
- Drying · Sanding with C20041 (h)
- 6–12 hrecommended
- Drying · Conditions
- 20 °C
- Lightfastness
- not statedrecommended
- Hardness
- lower than with C20040 (trade-off for elasticity)recommended
- Primer part A solids %
- 76 %dealer
- Primer part A viscosity
- 25 ± 2 sdealer
Application
HVLP
- Nozzle
- 1.8–2.2 (typ. 2) mmrecommended
- Pressure · air
- 2–2.5 barrecommended
- Spray viscosity
- 25–35 s DIN4recommended
- Consumption
- 150 g/m²dealer
- Coats
- 1–2recommended
- Flash-off
- 15–20 minrecommended
- Recoat
- enamel (PPL/RAL) after sanding, not before ~6 h; overnight preferredrecommended
- Sanding between coats
- P280–P320 (dealer) or K120 abrasive mat (schedule)dealer
The hardener is never applied on its own. Weigh the primer and 20 % C20041, stir, add S50, let it stand 5–10 min, strain. Don't flex parts until fully cured.
Airmix (air-assisted airless)
- Nozzle
- 0.28–0.33 mm (11–13 thou), 40–60° fanrecommended
- Pressure · fluid
- 60–100 barrecommended
- Pressure · air
- 1–2 barrecommended
- Consumption
- 150 g/m²dealer
For production runs; HVLP is handier on small decor.
Conventional spray
- Nozzle
- 1.8–2 mmrecommended
- Pressure · air
- 3–4 barrecommended
- Consumption
- 150 g/m²dealer
Process and compatibility
- Substrate preparation
- thoroughly degrease PU foam / polystone, then PPS400xx adhesion primercatalog
- Sanding
- P280–P320 by hand (dealer) or K120 mat (schedule); with C20041 wait longer than the 3–4 h given for the standard C20040dealer
- Temperature and humidity
- 20–25 °C (schedule); RH below ~70 %schedule
- Don'ts
- Don't blend with C20040/PC20042/PC20 — they're alternatives, not additives.
- Don't go over 20 % 'for more flex' — excess isocyanate leaves a soft or brittle, badly cured film.
- Don't sand at 3–4 h like with the standard hardener — the film is still soft and clogs paper.
- Don't leave the can open — moisture ruins hardener.
- Not for use with water-borne products.
Storage
- Storage temperature
- +5…+25 °C, dry, tightly closedrecommended
- After opening
- reseal at once; discard if cloudy, skinned or gelledrecommended
Safety: Contains isocyanates. Wear overalls, gloves and goggles; when spraying use an A2P3 respirator or air-fed mask and good extraction. Anyone sensitised to isocyanates must not use it. Flammable — keep away from ignition sources. Dispose of waste at an approved site.
Sources
Value tags: “official”, “dealer”, “catalog”, “schedule” are Technocolor data; “workshop” is from our own datasheets; “recommended” is our engineering estimate (hover to see the reasoning).
- PPS40043 dealer page: C20041 note; solids A 76±1 %, 25±2 s CF-8, pot life 3 h, touch 30 min, full 6 h (standard hardener)
- PPS40045 dealer page: same note and specs; S50 20–30 wt % / 40–50 vol %; 150 g/m²
- PPS40042 dealer page: same note; instruction 150 g/m², dry 3–4 h, sand P280–P320, PPL enamel 150 g/m²
- woodonline PPS40040 page: same C20041 note
- Technocolor catalogue 2019 «Лаки и краски для профессиональной отделки древесины», PU primers page (readkong transcript): PPS400xx hardener С20040, С20041 20 %, S50 20–25 %, solids 76 %; hardener chemistry groups
- official PPU finishing schedule (uses C20040 20 %, S50 30 %, 150 g/m², 4 h at 20–25 °C, K120 mat)
- official PPS40 page: PC20042 20 wt %/30 vol %, PC20 25/35, S50 20–30
- definitions of elasticity, adhesion, pot life
- application methods
- dealer search — no result (also PC20041, С20041, 20041, C20040, PC20042)
Not covered by the sources
- no official t-color.ru page, no dealer listing (t-colormarket.ru search empty 2026-10-04), no TDS/SDS found (web search budget exhausted this session)
- current code unconfirmed (C20041 vs PC20041) and whether still produced
- solids % of the hardener
- density
- isocyanate type (aromatic vs aliphatic)
- pot life of the C20041 mix (only standard-hardener 3 h known)
- drying/sanding times with C20041 (only 'slower' stated)
- volume ratio (weight 20 % only)
- packaging sizes, shelf life, price
- quantified elasticity (Erichsen) / hardness
- whether C20040 = current PC20042