PC73
PC73 Adhesion PU hardener
Special polyurethane hardener for the PTS73 adhesion primer. Its only published pairing is PTS73 (30–50 % by weight and by volume), which is thinned with the polyester thinner S11 and applied to furniture fronts and panels faced with melamine paper, and over solid wood. PC73 is not on the 2025–2026 catalog hardener chart — it is a niche component, supplied to order by dealers.
- Second component of the PTS73 PU adhesion primer over melamine paper (furniture fronts, panels)
- Priming under a PU system over solid wood and melamine-paper-faced board
Ask about PC73
Answers are based on the PC73 data and the products it mixes with.
Characteristics
- Chemistry
- PU (isocyanate) hardener, adhesion gradedealer
- Solids · Host part A
- 20 ± 1 %dealer
- Lightfastness
- assume NOT non-yellowing — keep it under a topcoat; don't use for clear finishes on pale timber without a testrecommended
- Moisture sensitivity
- isocyanate hardeners are sensitive to waterofficial
- Pot life
- over 4 hdealer
- Drying · Full dry (min)
- 30–40 mindealer
- Drying · Conditions
- 20 °C
- Interior or exterior
- interior use (PTS73 system)dealer
Application
HVLP
- Nozzle
- 1.3–1.5 (host PTS73 mix)recommended
- Pressure · air
- inlet 2.0–2.2 bar with trigger pulled, air cap ≤ 0.7 barrecommended
- Spray viscosity
- 14–18 s DIN4 for the PTS73 + PC73 + S11 mixrecommended
- Consumption
- 80–100dealer
- Coats
- 1 thin, even coatrecommended
Weigh PC73 into PTS73, stir, then add S11; stand 5–10 min and strain. Degrease melamine and scuff it (P240–P320) before priming.
Airmix (air-assisted airless)
- Nozzle
- 09 (0.009" ≈ 0.23 mm) tip, 40° fan; fluid pressure at the low end (≈15–20 bar), atomising air 1–1.5 barrecommended
Roller
- Consumption
- 8–12dealer
Roller-coater line: S11 near 20 %, 8–12 g/m² film.
Process and compatibility
- Goes with
- PTS73
- Thinners in mixes
- S11
- Substrate preparation
- melamine paper / solid wood: clean, degrease, scuffdealer
- Temperature and humidity
- work at 18–25 °C, RH ≤ 70 %recommended
- Don'ts
- Don't mix up PC73 with PC72/PC20 — PC73 is the only hardener published for PTS73
- Don't thin PTS73 with S50 — only S11 is listed
- Don't leave the can open: moisture ruins the hardener
- Don't exceed 50 % — excess hardener makes the film brittle
Storage
- Packaging
- под заказ (supplied to order), pack sizes not publisheddealer
- Storage temperature
- +5…+25 °C, tightly closed, dryrecommended
Safety: Contains isocyanates and organic solvents: flammable, respiratory irritant, may cause sensitisation. Work in a ventilated booth with a respirator (air-fed or A2P3 when spraying), nitrile gloves and goggles.
Mixed into
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).
- t-colormarket PTS73 page: PC73 «Отвердитель ПУ адгезивный» 30–50 % wt/vol, S11 20–100 % wt / 25–100 % vol, part A solids 20 ± 1 %, viscosity 100 ± 5 s VZ-4, pot life >4 h, full dry 30–40 min, spray 80–100 g/m², roller 8–12 g/m²
- linked PC73 page — HTTP 404 (checked 2026-10-04); /catalog/otverditeli_1/c73/ also 404; search q=PC73 returns nothing; re-checked 2026-10-05: still 404, search q=PC73 still empty
- woodonline PC73 card: «Используется как 2-й компонент в составе ПУ грунтов», type ПУ, to order
- woodonline PTS73 card: same PC73/S11 mix table; viscosity 100±5 s VZ-4; solids 20±1 %; full dry 30–40 min; substrates massiv + melamine paper; «изолирующий»; interior
- 2019 Technocolor catalog p.16: PTS73 solids 20 %, hardener С73 30–50 %, thinner S11 20–100 %
Not covered by the sources
- no official t-color.ru product page; dealer link /catalog/lkm/otverditeli/c73/ returns 404 (t-colormarket has no own PC73 page)
- PC73 solids, NCO content, viscosity, density, flash point not published
- aromatic vs aliphatic chemistry / yellowing resistance not published (absent from 2025–26 hardener chart)
- default ratio inside 30–50 % not published (40 % is derived)
- shelf life, storage temperature, pack sizes not published
- no official finishing schedule uses PC73/PTS73
- PTS73 part-A viscosity 100 ± 5 s VZ-4 published by dealer looks inconsistent with 20 % solids — unverified
- no Technocolor TDS/SDS PDF found for PC73 or PTS73
- no published spray nozzle / pressure / spray viscosity for PTS73 — all application settings are derived
- PTS73 dust-free / sanding / recoat times not published (only full dry 30–40 min)