Resposta rápida: compradores trabalhando em 2K polyurethane primers usually get a cleaner first shortlist when they separate three different jobs instead of treating every silicone additive as the same primer aid. CHLUMIAG® 3467 should move first when the primer still needs a compatibility-first route para anti-cratering, substrate wetting, and leveling. CHLUMIFE® 3370 deserves earlier review when the project is a true reactive 2K PU route and the team wants stronger leveling, gloss-hold surface refinement, and smoothness inside a polyurethane crosslinking system. CHLUMIFE® 3166 belongs earlier when the primer still needs a broader balance of surface smoothness, substrate wettability, dry feel, anti-blocking, and gloss support, but the team can keep its pinhole, whitening, and foam watchpoints visible.
That is the commercially useful split. This page is not another broad coating-additives overview, and it is not a duplicate of the already-live 2K polyurethane topcoat ou waterborne primer pages. It is a new CHLUMICRYL® application page for buyers whose project lives specifically in the 2K PU primer window and who need a faster first screen before moving into the finish layer.
Why 2K polyurethane primers deserve their own additive page
A 2K polyurethane primer does a different job from a topcoat, and it also lives in a different system lane from a waterborne primer. In real B2B formulation work, primer teams usually are trying to stabilize surface entry, crater tolerance, nivelamento, and a sufficiently clean surface for the next coating step, rather than chasing the same final-feel priorities that dominate a finish coat.
That makes a stage-specific primer page worth publishing. Longchang already has broader live pages for CHLUMICRYL® Aditivos para tintas e revestimentos, aditivos niveladores, seleção aditiva orientada por defeitos, waterborne primers, e 2K polyurethane topcoats. Those pages explain the branch. This page answers the narrower question that often appears one step earlier in the line: which additive deserves the first sample round when a 2K PU primer still needs cleaner compatibility, better leveling inside a reactive PU route, or broader surface balance before topcoat?
What the current company-supported evidence actually separates
- CHLUMIAG® 3467 is supported by Longchang as a polissiloxano modificado multicomponente that prioriza a compatibilidade do sistema. The company page directly supports anticratera, molhamento do substrato, e nivelamento, with addition logic that fits either polyurethane modification or direct coating modification. Supported dosage is 0,05% a 1% of total formulation for solvent systems, 0,5% a 5% of resin amount for resin modification, and 0,5% a 5% of total formulation for water-based systems.
- CHLUMIFE® 3370 is supported by Longchang as a reactive hydroxyl polyester-modified polysiloxane that reacts with isocyanate e é suitable for two-component polyurethane crosslinking systems. The company page frames it around surface leveling, higher gloss, e better smoothness, with a supported dosage of 0.05% to 3% of total formulation. It can be added at any stage of production or later, and the current company page supports it in UV and solvent systems, not water-based systems.
- CHLUMIFE® 3166 is supported as a poliorganosiloxano modificado com poliéter para Sistemas à base de UV, solventes e água. Longchang supports reduced surface tension, molhabilidade do substrato, suavidade da superfície, resistência a arranhões, anti-bloqueio, nivelamento, melhoria do brilho, and especially excelente sensação de secura. The recommended dosage is 0,05% a 1%, with explicit cautions around pinholes, whitening, and possible foam stabilization.
That is enough company-supported separation to build a real buyer page. External framing is used only conservatively for the general industry point that a 2K PU primer additive decision usually splits into compatibility-first defect cleanup, reactive primer leveling inside the PU route, e broader surface-balance work before the finish layer.
Tabela de comparação rápida: qual rota merece aparecer em primeiro lugar?
| Buyer priority in 2K PU primers | Melhor primeira rota | Por que ele deve ser o primeiro? | Posto de observação principal |
|---|---|---|---|
| Compatibility-first anti-cratering, substrate-wetting, and leveling control in a more formulation-sensitive primer package | CHLUMIAG® 3467 | Longchang explicitly prioritizes system compatibility and supports anti-cratering, wetting, and leveling, plus polyurethane-modification use | Its supported caution is that the feel is slightly less refined when compared with more feel-led routes |
| Reactive 2K PU leveling and smoother primer-surface preparation before the finish layer | CHLUMIFE® 3370 | Longchang positions it for two-component polyurethane crosslinking systems and ties it to leveling, gloss, and smoothness | Keep the system boundary visible because the current company page supports UV and solvent routes, not water-based systems |
| Broader surface balance across wettability, smoothness, dry feel, anti-blocking, leveling, and gloss support | CHLUMIFE® 3166 | Longchang supports it across UV, solvent, and water-based systems with a wider surface-performance balance | Pinhole, whitening, and foam-stabilization risk should be screened early |
Quando CHLUMIAG® 3467 é a melhor primeira opção
3467 should move first when the 2K PU primer still looks compatibility-sensitive and the main question is whether the team can stabilize anti-cratering, substrate wetting, and leveling without narrowing the formulation window too fast. Longchang’s current product page is unusually helpful here because it does not position 3467 only as a generic leveling aid. It explicitly says the product prioriza a compatibilidade do sistema, and it also supports use for polyurethane modification.
That matters in 2K primer work. Some primer programs are not failing because the lab chose the wrong surface family in the abstract. They are failing because the system is still sensitive and the first screen needs a route that keeps formulation tolerance visible while still addressing crater and wetting pressure.
- Supported strengths: anti-cratering, substrate wetting, leveling, and compatibility-first behavior
- Lógica de adição: can be added with the polyol during resin prepolymerization, added later in polyurethane modification, or added directly to the coating system
- Ajuste do sistema: Sistemas à base de UV, solventes e água
- Atenção principal: Longchang notes that the feel is slightly less refined, so it should not be the automatic first choice if the project already has moved into a more feel-led or premium-finish target
In short, 3467 is the cleaner first screen when the primer team needs compatibility-first control before worrying about a more reactive or broader feel-balance route.
When CHLUMIFE® 3370 is the better first move
3370 should move earlier when the buyer is working on a true reactive 2K polyurethane route and wants the additive choice to stay inside that system logic. Longchang supports 3370 as a reactive hydroxyl polyester-modified polysiloxane that reacts with isocyanate so the organosilicon can combine with the resin system in block or graft form. The company page also says it is suitable for two-component polyurethane crosslinking systems.
That makes 3370 commercially useful when the primer already is clearly a 2K PU system and the first question is not only broad wetting correction. It is whether the lab can achieve better leveling, smoother primer laydown, and a cleaner surface before the next coating stage without stepping outside the reactive polyurethane route.
- Supported strengths: leveling, higher gloss, and better smoothness
- Recommended dosage: 0.05% to 3% of total formulation
- Lógica de adição: can be added at any stage of production or later
- Ajuste do sistema: supported in UV and solvent systems, not water-based systems on the current company page
So 3370 is the better first benchmark when the buyer needs a reactive 2K PU primer route rather than a more compatibility-led or broader multi-system route.
Quando CHLUMIFE® 3166 é a melhor primeira opção
3166 deserves earlier review when the primer still needs a broader surface-balance route before the topcoat stage. Longchang’s company page positions 3166 around controle de tensão superficial, excelente sensação de secura, molhabilidade do substrato, suavidade da superfície, anti-bloqueio, nivelamento, e melhoria do brilho. That is a different first-screen role from 3467’s compatibility-first logic or 3370’s reactive-PU route.
This makes 3166 useful when the primer problem is still broader than one narrow crater or reactive-chemistry decision. Some teams need a first route that helps them judge whether the primer surface can become cleaner, smoother, and easier to handle before they narrow into a more specialized option.
- Supported strengths: substrate wettability, surface smoothness, anti-blocking, leveling, gloss support, and excellent dry feel
- Recommended dosage: 0,05% a 1% da formulação total
- Lógica de adição: can be added at any stage, and can be diluted first for easier addition
- Atenção principal: Longchang explicitly warns about pinholes, whitening, and possible foam stabilization, so a defoamer check should stay visible during qualification
That makes 3166 the better first route when the lab still needs a broader primer-surface read before it narrows into a tighter compatibility or reactive-system decision.
How buyers should choose before the first sample round
1. Start with the real stage of failure
If the primer still looks compatibility-sensitive and crater-prone, start with 3467. If the line already is clearly a 2K PU reactive route and needs a cleaner primer surface before the finish layer, move 3370 earlier. If the primer still needs a broader balance across wettability, smoothness, and handling, start with 3166.
2. Keep the system boundary visible
3467 and 3166 both sit across wider system windows. 3370 does not. That alone can save time when the team is screening more than one primer route in parallel.
3. Keep compatibility logic separate from reactive-route logic
Both 3467 and 3370 can touch leveling, but the supported selection logic is not the same. One is a compatibility-first route. The other is a reactive polyurethane route tied directly to isocyanate-crosslinking systems.
4. Use the watchpoint, not only the headline benefit
3467 keeps formulation tolerance visible but is not the most feel-led option. 3370 is best treated as a true 2K PU route, not a general water-based shortcut. 3166 can be broad and useful, but its pinhole, whitening, and foam watchpoints should be screened early.
5. Mantenha a primeira rodada equilibrada.
For many 2K PU primer projects, one compatibility-first route, um reactive PU routee um broader surface-balance route teach more than an overloaded first panel packed with near-neighbor additives.
Caminho recomendado para Longchang a partir desta página
- Visão geral do cluster: CHLUMICRYL® Aditivos para tintas e revestimentos
- Related stage-specific page: How to Choose Additives for Waterborne Primers
- Related finish-layer page: How to Choose Surface Additives for 2K Polyurethane Topcoats
- Página de funções relacionadas: Como escolher aditivos niveladores para revestimentos e tintas
- Related diagnosis page: Aditivo umectante vs. aditivo nivelador vs. antiespumante vs. surfactante fluorado em revestimentos e tintas
- 3467 product page: CHLUMIAG® 3467
- 3370 product page: CHLUMIFE® 3370
- 3166 product page: CHLUMIFE® 3166
PERGUNTAS FREQUENTES
Which additive should I screen first if my 2K PU primer still shows crater risk and formulation sensitivity?
Usually CHLUMIAG® 3467, because Longchang directly supports it around compatibility-first use, anti-cratering, substrate wetting, leveling, and polyurethane-modification routes.
When should 3370 move ahead of 3467?
3370 should move ahead when the project is clearly a reactive two-component polyurethane route and the main target is cleaner leveling and surface refinement inside that PU crosslinking system.
When does 3166 make more sense than the other two?
It makes more sense when the primer still needs a broader surface-balance screen across wettability, smoothness, anti-blocking, and handling, rather than only a compatibility-first or reactive-system decision.
Is this page the same as the 2K PU topcoat page?
No. The topcoat page is built around finish-layer selection logic. This new page is for the primer stage and helps buyers screen compatibility-first crater control, reactive primer leveling, and broader pre-topcoat surface balance.
Need a faster shortlist for 2K polyurethane primers?
If your primer project is stuck between compatibility-first defect cleanup, reactive PU leveling, e broader surface balance before topcoat, define the real first-screen job before requesting samples. That usually shows much faster whether 3467, 3370, or 3166 deserves the first round.