Jawaban singkat: pembeli sedang mengerjakan 2K polyurethane basecoats usually get a cleaner first shortlist when they separate three different additive jobs instead of asking one silicone route to solve every surface problem at once. CHLUMIWE® 3071 should move first when the basecoat still needs better substrate wetting, spread, and first-contact entry. CHLUMIAG® 3467 deserves earlier review when the system is still compatibility-sensitive and the main pressure sits around anti-cratering, pullback control, and broader leveling stability. CHLUMIFE® 3370 belongs earlier when the buyer already is in a true 2K polyurethane crosslinking route and wants a reactive leveling and gloss-hold path before the finish layer.
That is the commercially useful split. This page is intentionally narrower than Longchang’s already-live 2K polyurethane primer, 2K polyurethane topcoat, Dan 2K polyurethane clearcoat pages. Those pages solve adjacent stage questions. This new page answers the tighter B2B decision that sits in the middle: which additive route deserves the first sample round when the 2K PU basecoat still is not laying down cleanly enough before the next layer?
Why 2K polyurethane basecoats deserve their own additive page
A basecoat is not judged the same way as a primer or a final clear layer. In many practical polyurethane coating builds, the basecoat is the appearance-setting middle layer. Buyers usually care about whether the film wets the substrate cleanly, whether crater or pullback risk is under control, and whether the basecoat can level well enough before the next coating step locks in the result.
That makes a dedicated basecoat page worth publishing. Longchang already has broader live pages for the Pelapis dan Aditif Tinta CHLUMICRYL® hub, the cross-function coating defect additive selection page, and the stage-neighbor pages for 2K PU primers, topcoats, and clearcoats. Those pages explain the larger branch. This page answers a narrower buyer question: should the first additive decision in a 2K PU basecoat focus on substrate entry, compatibility-first crater cleanup, or reactive leveling inside the polyurethane route?
General industry framing also supports that split. External coating references commonly separate wetting and substrate-entry problems from crater-sensitive compatibility issues and from final leveling inside a reactive PU build. That outside framing is used here only conservatively. The product-specific facts below stay tied to Longchang-supported product pages.
What the current company-supported evidence already separates
- CHLUMIWE® 3071 is supported by Longchang as a polisiloksan yang dimodifikasi polieter dengan low viscosity dan low surface tension, providing excellent spreadability, wetting, and penetration. The current company page also frames it as useful on difficult-to-process substrates and says it can improve flow, leveling, recoatability, and gloss retention. Supported dosage is 0,1% hingga 1,0%, and the product can be added during grinding, stirring, or after production.
- CHLUMIAG® 3467 is supported by Longchang as a agen perata reaktif dan polisiloksan termodifikasi multi-komponen. The company page states that it can graft onto polyurethane resins through reaction of its hydroxyl groups with isocyanates and directly supports leveling, anti-cratering, and substrate wetting. It is also positioned around polyurethane modification or direct coating modification. Supported dosage is 0,05% hingga 1% of total formulation for solvent systems and 0,5% hingga 5% for resin modification or water-based systems.
- CHLUMIFE® 3370 is supported by Longchang as a reactive hydroxyl polyester-modified polysiloxane. The current company page says it reacts with isocyanate, is suitable for two-component polyurethane crosslinking systems, and improves surface leveling, gloss, and smoothness. Supported dosage is 0.05% to 3% of total formulation, and the page keeps it in Sistem UV dan pelarut, not water-based systems.
That is enough company-supported separation to build a real 2K PU basecoat buyer page without inventing unsupported resin chemistry or application claims.
Tabel perbandingan singkat: rute mana yang layak ditampilkan di layar pertama?
| Observed 2K PU basecoat situation | Rute pertama terbaik | Mengapa ini harus didahulukan? | Titik pengawasan utama |
|---|---|---|---|
| The basecoat still struggles with surface entry, spread, or uniform first-contact laydown before the team can honestly judge crater behavior | CHLUMIWE® 3071 | Longchang supports it directly around low surface tension, spreadability, wetting, penetration, and broader flow or recoatability support | Its company page notes a possible foam-stabilizing effect, so buyers should keep that risk visible during formulation screening |
| The system already is in a polyurethane route but still looks compatibility-sensitive, with crater, pullback, or broader leveling instability | CHLUMIAG® 3467 | Longchang positions it as a reactive leveling route that can graft into polyurethane systems and supports anti-cratering, substrate wetting, and leveling together | The company page says it prioritizes compatibility, so buyers chasing a more refined hand feel may still need a later finish-layer check |
| The 2K PU basecoat route already fits directionally, but the film still needs cleaner reactive leveling, gloss hold, and smoother appearance before the next layer | CHLUMIFE® 3370 | Longchang supports it specifically for two-component polyurethane crosslinking systems, with reactive isocyanate-linked leveling, gloss, and smoothness | The current company page does not position it for water-based systems, so keep it inside the supported system window |
When CHLUMIWE® 3071 is the better first move
3071 should move first when the basecoat still has not entered the substrate cleanly enough. This is the better route when the film shows weak spread, unstable first-contact coverage, or a laydown problem that appears before the team can even judge whether crater control or reactive leveling is the real next bottleneck.
That supported logic matters because Longchang does not position 3071 only as a vague wetting additive. The current company page keeps together low surface tension, spreadability, wetting, penetration, and broader support around flow, leveling, recoatability, and gloss retention.
3071 is usually the better first route when:
- the basecoat still is not entering the substrate or previous layer cleanly,
- the film lays down unevenly before a more specific crater diagnosis is even possible,
- the buyer wants a first screen that improves surface entry without jumping immediately into a stronger reactive or compatibility-first route, or
- the project needs a faster wetting benchmark before moving into more specialized PU additive decisions.
The watchpoint stays practical. Longchang notes that 3071 may have a foam-stabilizing effect, so the lab should not ignore air-release behavior while screening it.
When CHLUMIAG® 3467 is the better first move
3467 deserves the earlier screen when the 2K PU basecoat already sits inside the right polyurethane lane but still behaves as a compatibility-sensitive surface problem. This is the stronger first route when the basecoat shows crater risk, pullback, or unstable leveling that is harder to solve with simple wetting correction alone.
The current Longchang-supported page is direct here. 3467 is not positioned only as a general silicone. It is described as a agen perata reaktif yang dapat dicangkokkan ke polyurethane resins through reaction of its hydroxyl groups with isocyanates. The same page also supports anti-cratering, substrate wetting, and leveling, which is exactly why it earns a compatibility-first place in a 2K PU basecoat shortlist.
3467 is usually the better first route when:
- the basecoat still shows crater, pullback, or anti-cratering pressure inside a PU system,
- simple wetting correction is not enough because the package still looks formulation-sensitive,
- the buyer wants one first screen that keeps together leveling, crater control, and substrate wetting, or
- the development path may include polyurethane modification rather than only late direct addition.
This route is especially useful when the basecoat is not failing because of one isolated surface symptom, but because the full polyurethane surface-control window still is not stable enough.
When CHLUMIFE® 3370 is the better first move
3370 belongs earlier when the 2K polyurethane basecoat already is broadly compatible, but the team still needs a more specific reactive leveling and appearance-control route before the next layer. This is the stronger route when the buyer wants cleaner flow-out, smoother appearance, and better gloss hold inside a true two-component polyurethane crosslinking system.
The supported company evidence is narrow but useful. Longchang positions 3370 as a reactive hydroxyl polyester-modified polysiloxane that reacts with isocyanate, is suitable for two-component polyurethane crosslinking systems, and improves surface leveling, gloss, and smoothness. That is the cleaner fit when the basecoat already wets directionally and the next question is how to refine its reactive appearance before the finish layer.
3370 is usually the better first route when:
- the coating line already is committed to a true 2K PU route,
- the basecoat needs smoother flow and better visible appearance rather than only broader wetting correction,
- the lab wants a more specifically reactive PU leveling benchmark, atau
- the next coating step will expose any remaining roughness or weak laydown too clearly to ignore.
The boundary matters. The current company page keeps 3370 in Sistem UV dan pelarut, not water-based systems, so buyers should keep the first screen inside that supported window.
How buyers should choose before the first sample round
1. Decide whether the basecoat problem starts with entry, compatibility, or reactive leveling
If the film still cannot spread or enter cleanly, start with 3071. If the surface already enters but still shows crater-sensitive instability, move earlier to 3467. If the package is directionally right and the main target becomes smoother reactive appearance before the next layer, 3370 deserves the earlier test.
2. Keep the stage logic separate from primer and topcoat logic
Do not force a primer-style or clearcoat-style answer onto a basecoat. The basecoat usually has to become uniform enough for the next layer, so the first additive decision should match that middle-stage job instead of repeating a general coating article.
3. Keep the polyurethane route visible
3467 and 3370 are both commercially useful here because the company-supported pages keep them attached to polyurethane logic rather than only generic silicone language. If the trial plan ignores whether the route is a true 2K PU system, the comparison becomes less useful.
4. Keep watchpoints inside the first trial design
3071 may stabilize foam. 3467 prioritizes compatibility more than refined feel. 3370 is not positioned by Longchang for water-based systems. Those watchpoints should sit inside the first panel plan instead of being rediscovered later.
5. Keep the first sample set small
For many 2K PU basecoat projects, a practical first plan is one 3071 substrate-entry route, satu 3467 compatibility-first crater-control route, dan satu 3370 reactive leveling route. That usually teaches more than screening a crowded set of near-neighbor additives without a clear decision frame.
Rute Longchang yang direkomendasikan dari halaman ini
- Substrate wetting route: CHLUMIWE® 3071
- Compatibility-first crater-control route: CHLUMIAG® 3467
- Reactive PU leveling route: CHLUMIFE® 3370
- Gambaran umum klaster: Pelapis dan Aditif Tinta CHLUMICRYL®
- Related stage page: How to Choose Surface Additives for 2K Polyurethane Primers
- Related stage page: Cara Memilih Aditif Permukaan untuk Lapisan Atas Poliuretan 2K
- Related stage page: How to Choose Surface Additives for 2K Polyurethane Clearcoats
- Halaman cacat terkait: Wetting Additive vs Leveling Additive vs Defoamer vs Fluorine Surfactant in Coatings and Inks
- Halaman fungsi terkait: Cara Memilih Aditif Perata untuk Pelapis dan Tinta
PERTANYAAN YANG SERING DIAJUKAN
What is the best first additive if the 2K PU basecoat still does not wet cleanly?
Usually 3071, especially when the visible problem still starts with spread, penetration, and first-contact laydown rather than a clearly reactive PU leveling issue.
When should I test 3467 before 3370?
Test 3467 earlier when the basecoat still looks compatibility-sensitive and crater-prone. Test 3370 earlier when the package already is directionally stable and the remaining target is smoother reactive leveling and gloss hold.
Why is 3370 not the first answer for every 2K PU basecoat?
Because some basecoat failures start before reactive appearance refinement matters. If the film still is not entering the surface or still is cratering from a broader compatibility issue, 3071 or 3467 may teach the lab more in the first round.
Can one of these routes solve every basecoat defect?
No. Their supported first-screen jobs are different enough that buyers should not treat them as interchangeable. The faster path is to identify whether the basecoat is failing at substrate entry, compatibility-sensitive crater control, or reactive leveling.
Is this page meant for water-based 2K PU basecoats too?
Only partly. 3071 and 3467 both have company-supported water-based windows. 3370 does not. So buyers should keep the supported system boundary visible instead of assuming all three routes are interchangeable in water-based 2K PU work.
Need a tighter shortlist?
If your 2K polyurethane basecoat still is not laying down cleanly, stop treating it as one generic silicone-additive problem. First decide whether the real bottleneck is substrate wetting and spread, compatibility-first crater cleanup, atau reactive PU leveling before the finish layer. That usually makes the next CHLUMICRYL® sample decision much faster.