Silicone Surface-Control Additives

1. What functions do silicone surface additives perform?

Four functions are often confused:

Anti-cratering and anti-blocking are further effects some grades provide: BYK’s BYK-333 data sheet lists strong surface-tension reduction, better substrate wetting, avoidance of cratering, increased slip and gloss, and improved anti-blocking in aqueous systems (S2). See the guide How do wetting, leveling, slip and release differ?

2. What are silicone surface additives, chemically?

Most are organomodified polydimethylsiloxanes. BASF describes organomodified silicones used as substrate wetting, flow and leveling, or slip agents depending on the modification and silicone content (S1). BYK-333 is a polyether-modified polydimethylsiloxane (S2); TEGO Glide 450 is a polyether siloxane copolymer supplied as a 100% active clear liquid (S3). A superwetter article describes silicone polyether copolymers as low-viscosity, low-molecular-weight materials, where ethylene-oxide content affects solubility and compatibility with the formulation rather than water surface tension directly (S4).

Glossary: substrate wetting, wetting, surface tension, dynamic surface tension.

3. What other names are used?

Suppliers use: wetting agent, surface modifier, surface additive, flow and leveling additive, slip additive, anti-crater additive, silicone surfactant, superwetter, organomodified siloxane, polyether-modified siloxane, polyether siloxane, silicone polyether copolymer. Names overlap: a “wetting agent” may be silicone or non-silicone; a “slip additive” may be silicone, wax or a polyester-modified silicone. Always request the chemistry class, active content, carrier and the intended function.

4. Which industries and systems use them?

Typical systems named in manufacturer literature include solvent-borne, solvent-free and aqueous coatings; printing inks and overprint varnishes; adhesive systems based on polyurethanes, epoxies and acrylates; and ambient-curing polyurethane and epoxy plastic systems (BYK-333, S2). BASF and Evonik examples include car OEM and repair coatings, wood coatings and plastic coatings, in 2-pack and 100% radiation-curing systems (TEGO Glide 450, S3). A superwetter article reports tests in polyurethane and acrylic wood lacquers on glass, in a PET flexographic ink and in a solventless UV-curable coating (S4).

5. When are silicone surface additives suitable, and when not?

Reasonable candidates (subject to trials): defects where the liquid does not wet the substrate (beading, crawling), craters caused by surface-tension differences, a need for higher gloss or slip, or poor wetting of low-energy plastic films.

Not a cure for: contamination (oil, silicone, dust), poor surface preparation, unsuitable rheology, mismatched resin–solvent systems or application errors. An additive “should not replace basic process control” (guide section “Which process causes affect flow and leveling?”). Needs extra caution: any film that will be recoated, overprinted, laminated or bonded, because silicone at the surface can impair later adhesion.

6. What do published data sheets say about density, form and addition level?

Values are grade-specific. The two data sheets read for this page give: BYK-333, density 1.04 g/mL at 20 °C, general addition 0.05–0.3% additive (as supplied) on total formulation, up to 1% in aqueous and UV systems, “for orientation only”; and TEGO Glide 450, 100% active, 0.05–0.7% as supplied on total formulation, with 60 months’ shelf life in unopened original packaging (S2, S3). Another grade will differ. Do not copy these figures to a different additive.

7. Why do surface tension and surface energy decide wetting?

A liquid wets a solid when its surface tension is lower than the substrate’s surface energy. BASF states the contact-angle criteria: little to no wetting above 90°, partial wetting below 90°, and wetting at about 0°; solid surface energy is determined indirectly from contact angles with liquids of known surface tension (Young equation) (S1). The table gives the brochure’s example values.

8. What controls leveling, and why can a film still show orange peel?

BASF states that leveling time is proportional to viscosity and inversely proportional to surface tension and to the third power of film thickness, so doubling the film thickness shortens leveling time by a factor of eight; orange peel is surface bumpiness that often results from poor leveling (S1). That means film thickness, viscosity, drying speed and surface-tension gradients all matter, and a surface additive is only one lever. Evonik’s slip and flow guidance and BYK’s leveling notes make the same point: record thickness, application method, ambient conditions and cure sequence when comparing panels (guide section “Which process causes affect flow and leveling?”).

9. What is the difference between static and dynamic surface tension?

Static (equilibrium) surface tension is measured when the liquid surface has settled, for example by the du Noüy ring or Wilhelmy plate methods. Dynamic surface tension is measured on rapidly renewed surfaces, as in a bubble-pressure tensiometer, and describes how quickly the additive reaches a new interface. BASF names the du Noüy ring for static and a bubble-pressure tensiometer for dynamic surface tension (S1). The superwetter article measured static surface tension at 0.1 wt% in water with a Wilhelmy plate, and dynamic surface tension at 0.2 wt% with a bubble tensiometer at 1 and 5 Hz (S4). Spraying, printing and roll coating create new interface in fractions of a second, so a low static value does not guarantee wetting at line speed.

10. Why do silicone wetting additives stabilise foam?

Surface-active molecules that strongly lower surface tension can also stabilise foam films. In the superwetter study, superwetters and competitor additives all showed some foam stabilisation, the strongest wetters produced the most foam, and 0.1 wt% of a defoamer reduced it (S4). BASF rates polysiloxane additives as foam stabilising in its qualitative table (S1), and the BYK-333 data sheet says tests should determine whether foam is stabilised in the specific system and notes that, in ambient-curing systems, adding the additive at the end of the process has helped avoid foam stabilisation (S2). Foam control and surface additives therefore have to be developed together; see Industrial defoamers and antifoams.

11. How do surface additives affect recoat, overprint and adhesion?

BASF’s table rates polysiloxane as having a high possibility of intercoat adhesion problems, and notes each resin–silicone combination has an optimum silicone level, with higher levels risking loss of intercoat adhesion without added benefit (S1). The BYK-333 data sheet likewise says cratering, recoatability and the influence on adhesion should be verified in testing (S2). Reactive and non-reactive additives migrate differently; that difference changes durability and overprintability, and “reactive” is not automatically safer. Always run the actual recoat, overprint, lamination or bonding step after the intended cure and ageing (guide section “How should downstream adhesion be included in a wetting-additive trial?”).

12. How is slip described and measured?

Slip is the lowering of the coefficient of friction (COF) of the cured surface. For plastic film and sheeting, ASTM D1894 describes determining the static (starting) and kinetic (sliding) coefficients of friction under specified test conditions, with a standard test temperature of 23 °C; the current edition in the catalogue is D1894-24 and the method is stated as not equivalent to ISO 8295 (S7). In a superwetter study, one slip additive (DC 57) gave weak wetting and a large drop in slip while the wetting additives caused no change in slip (S4), which shows that wetting and slip must be specified independently. Do not set a universal COF target: it depends on the contact pair, load, speed and handling outcome.

13. What are the temperature limits of silicone surface additives?

Manufacturer data are grade-specific. BASF states that polyether modifications on organomodified silicones begin to decompose at about 140–150 °C and that decomposition products may include unmodified silicone oil, which can harm intercoat adhesion; alkyl-modified silicones are suggested for higher-temperature applications (S1). The same article credits one wetter’s non-reactive acetoxy end-capping with long-term stability at high pH (S4). For stoving, powder-adjacent or extrusion-coating processes, request the supplier’s heat-stability data for the exact grade.

14. How is compatibility with the binder and solvent system judged?

Compatibility depends on structure and on the formulation. For polyether silicones, ethylene-oxide content affects solubility and compatibility rather than water surface tension (S4). A range of HLB (hydrophilic–lipophilic balance) values lets formulators match a grade to the system. Check haze, turbidity, separation on storage, crater-sensitivity, and the supplier’s recommendations on carrier, pre-dilution and addition stage. Do not mix concentrated additives together (guide section “Compatibility and incorporation”).

15. When and how should the additive be added during manufacturing?

Follow the exact grade’s instructions. Data sheets typically allow addition as supplied or as a pre-dilution in a suitable solvent to simplify dosing (S3), and some systems benefit from adding at the end of the batch to limit foam (S2). Keep the incorporation method used in a successful trial; a different production sequence, mixing energy or addition stage can change the result (guide section “Compatibility and incorporation”). Use accurate dosing: at 0.05–0.3% on a batch, small errors in addition mass are relatively large.

16. How do application method and speed affect results?

Spraying, curtain coating, roll coating, flexographic and gravure printing, and drawdown create interface at very different rates and film thicknesses. Evaluate wetting on the actual substrate and at the relevant line speed, not only on a laboratory drawdown or beaker test (guide section “Dynamic wetting, levelling and intercoat compatibility”). Record film thickness, application route, ambient conditions and cure sequence for every trial.

17. How are silicone additives used in printing inks and overprint varnishes?

BYK-333’s listed applications include printing inks and overprint varnishes (S2). In a published study on a PET flexographic ink, two superwetters performed strongly with no change in slip, and in a solventless UV-curable coating one superwetter gave superior wetting with no slip impact (S4). Silicone in ink or varnish can impair overprinting, laminating and adhesive bonding, so ask the converter which next steps follow printing.

18. What defects are typically linked to surface additives?

Source basis: S1, S2, S4 and the guide section “Troubleshooting: avoid additive-by-symptom selection”.

19. What happens in storage and handling?

Silicone-polyether additives can turn turbid or separate at low temperature; BYK states this may occur below 5 °C and that the product should be warmed to 20 °C and mixed well (S2). TEGO Glide 450 data note reversible turbidity at low temperatures and 60 months’ shelf life in unopened original packaging (S3). Ask suppliers for storage temperature limits, shelf life and whether re-homogenisation is needed before use.

20. Which substrates and exposure conditions matter?

Substrate surface energy decides how hard wetting is. Low-energy plastics such as polypropylene (about 28 mN/m) and polyethylene (about 33 mN/m) are harder to wet than glass (about 70 mN/m) or PVC (about 40 mN/m) according to the BASF brochure (S1). Treatment (corona, flame, primer) and contamination (oil, mould-release, plasticiser migration) change real surface energy. For polyolefin films, wetting tension can be checked with dyne solutions; ASTM D2578 addresses wetting tension of polyethylene and polypropylene films, but its D2578-17 edition appears as “historical” in the catalogue, so confirm the current edition before citing (S6).

21. How should a wetting or crater problem be investigated?

1. Confirm the defect on a control panel and preserve the mixing and production record.
2. Check substrate cleanliness and surface energy (dyne test, contact angle).
3. Check formulation: surface-tension mismatch of resin, solvent and substrate; local contamination; incompatible additives.
4. Check application and drying: film thickness, viscosity, solvent balance, temperature, line speed.
5. Only then screen a surface additive, from a chemistry matched to the symptom, at a dose ladder.
6. Test the finished surface for the next operation: recoat, print, bond, lamination.

22. How should candidate additives and samples be chosen?

Ask the manufacturer to explain why a candidate fits the stated binder, substrate and process, and which side effects should be examined. Choose two to three structurally different candidates (for example one wetting-oriented, one leveling or slip-oriented), not several grades with the same chemistry. Agree the sample quantity with the trial scale: laboratory screening needs small volumes because addition levels are in tenths of a percent, but a scale-up trial needs enough for a full batch and a control.

23. How should a qualification trial be structured?

Source basis: guide section “Trial design: measure benefits and tradeoffs”.

24. Which documents should be requested?

Current technical data sheet and safety data sheet for the exact grade; composition or function description; active and as-supplied basis; incorporation instructions; storage and shelf life; traceability and change-notification terms; and written declarations for food contact, VOC, PFAS or other restrictions, each stating its scope and documentary basis. Neither a silicone-containing nor a silicone-free label establishes compliance of a finished coating or article (guide section “Testing and documentation”).

25. Which test methods and standards are relevant?

No standard certifies every wetting, leveling and adhesion outcome; ask a qualified laboratory to select current methods. The full text of the standards above was not read.

26. What acceptance criteria are sensible?

Define separate criteria for wetting (coverage, contact angle or visible defect-free area), leveling (appearance or gloss on the production article), slip (a measured COF only if slip is a requirement), foam (a defined foam test) and downstream adhesion (a defined recoat, print or bond test after ageing). The numerical limits belong to your product and customer specification; this page does not provide them. Improved coverage on a laboratory panel does not establish acceptable adhesion on the production article.

27. What changes from laboratory to production?

Mixing energy, addition point, batch size and ambient conditions differ. A dosage that worked in a 1 kg batch may behave differently at 1,000 kg because local over-concentration or shear history changes. Validate the actual production sequence, run the next-operation test on production samples, and confirm lot-to-lot consistency before approving a supplier.

28. Which commercial formats are common?

Surface additives are usually supplied as clear or hazy liquids in pails, drums or intermediate bulk containers, either neat (100% active) or as solutions or emulsions. Ask for active content, solvent or carrier, viscosity, flash point (for solvent-containing grades), container size and the minimum order or sample availability; none of these is established by this page.

29. What information is needed to request a quotation?

• Substrate and its preparation; coating, ink or adhesive system and application method.
• Defect description and when it appears; current additive package.
• The next operation: recoating, printing, bonding, release or contact handling.
• Existing test methods and acceptance ranges; regulatory restrictions in writing.
• Trial quantity, annual volume, packaging and destination.

Use the RFQ brief tool to assemble this in the browser.

30. What do purchasing teams usually ask?

Is the grade silicone-containing or silicone-free in writing; what is the active content and cost per unit of active; what dose does our system need; what is the shelf life; who manufactures it and where; how are formulation changes notified; and what regulatory declarations are available. Compare cost in use, including the cost of rejects, rework, surface preparation and qualification, rather than cost per kilogram alone.

31. How do silicone additives compare with non-silicone surface additives?

BASF lists non-silicone alternatives for wetting and leveling, including fluorinated polyacrylates (flow and leveling agents with fluorinated side chains), sulfosuccinates, alkoxylated surfactants and star-shaped polymers, and rates fluorocarbon-modified polyacrylates as low in intercoat-adhesion risk but good in foam stabilisation, while polysiloxanes are rated as high in intercoat-adhesion risk (S1). PFAS-related restrictions on fluorinated additives are an active regulatory topic; see PFAS-free coating additives. The right choice depends on whether silicone can be tolerated downstream and on regulatory and customer requirements. The comparison Substrate wetting versus pigment dispersion clarifies a frequent confusion.

32. What are the advantages and disadvantages?

Advantages: very low surface tension at small doses; improved wetting of difficult substrates; fewer craters caused by surface-tension gradients; improved gloss and slip in many systems; low addition levels. Disadvantages: foam stabilisation; risk of intercoat and overprint adhesion loss; potential for craters when incompatible or overdosed; possible thermal degradation of polyether modifications above about 140–150 °C (S1); contamination of equipment and downstream lines; grade-specific behaviour that can’t be transferred between products.

33. How should cost and performance be compared?

Calculate cost per treated tonne of finished coating at the lowest effective dose after a ladder test and compare aged performance. Include the cost of failed recoat or print operations. A low-cost additive that needs a higher dose or causes occasional defects may cost more in use.

34. What regulatory and sustainability questions arise?

Ask in writing for VOC content, silicone content, PFAS status, food-contact suitability, biodegradability or aquatic-toxicity information where relevant, and the jurisdiction each declaration covers. This page makes no declaration for any product. Silicone additives are used at tenths of a percent, so the question is usually about the finished article’s declarations rather than the additive’s share, but requirements differ by use.

35. What supplier qualification questions should be asked?

Who manufactures the grade and where; what quality system and documents support it; how formulation changes are notified; lot-to-lot consistency data; the technical-support path; and complaint handling. See the supplier qualification checklist. PAXOMER does not confirm any supplier’s approvals or capacity on this page.

36. Which related pages should I read next?

• Guide: Silicone wetting and surface-control additives
• Guide: Specialty coating additives
• Guide: PFAS-free coating additives
• Related page: Industrial defoamers and antifoams
• Related page: Industrial coating additives
• Comparison: Substrate wetting versus pigment dispersion

Engineering and purchasing FAQs

Each answer is general technical information, not a specification or a quotation.

Is wetting the same as adhesion?

How does a silicone wetting additive reduce craters?

Why does my coating foam more after I add a wetting additive?

How much silicone surface additive should I use?

Can silicone additives be used if the coating will be recoated or overprinted?

What is the difference between static and dynamic surface tension?

Why will a coating wet glass but bead on polypropylene?

What does a slip additive do, and how is slip tested?

Are silicone additives suitable at high temperature?

Is a silicone-free additive always safer for adhesion?

Which documents should I request from an additive supplier?

Does PAXOMER supply a particular silicone additive?

Technical References

References below were opened on the access date shown. A source supports only the statement it is cited for. Standards are cited by number and title from public catalogue entries; their full text was not read unless stated.

1. S1. Wetting Agents and Surface Modifiers (brochure). BASF. www.basf.com/dam/jcr:172fed1c-9f96-3e2f-9479-8a4fc0305275/basf/www/global/segmen (opens in a new tab) manufacturer literature · accessed 2026-10-27
   Surface tensions and energies, contact-angle criteria, leveling relationship, thermal limit of polyether modification and qualitative foam and intercoat-adhesion ratings. Figures are as read from text extraction.
2. S2. BYK-333 data sheet (issue 11/2012, hosted copy). BYK-Chemie, 2012-11. media.knowde.com/image/upload/v1733488148/TDS-BYK-333.pdf20241206-1-godtbj.pdf (opens in a new tab) manufacturer datasheet · accessed 2026-10-27
   Chemistry, density, addition levels, cautions and low-temperature storage. A hosted copy; current issue should be checked at byk.com.
3. S3. TEGO Glide 450 technical data (Evonik COATINO). Evonik Operations GmbH. www.coatino.com/products/PR_52006331 (opens in a new tab) manufacturer datasheet · accessed 2026-10-27
   Manufacturer technical page opened 2026-10-29; confirms chemistry, 100 % active, 0.05–0.7 % on total formulation and 60 months' shelf life.
4. S4. A New Era in Superwetters for Waterborne and UV-Curable Coatings and Inks. PCI Magazine (Paint and Coatings Industry). www.pcimag.com/articles/93299-a-new-era-in-superwetters-for-waterborne-and-uvcur (opens in a new tab) technical literature · accessed 2026-10-27
   Manufacturer-authored trade article with application tests; numeric surface-tension tables were images and not readable.
5. S5. ASTM D1331-20(2024), Surface and Interfacial Tension of Solutions of Paints, Solvents, Solutions of Surface-Active Agents, and Related Materials. ASTM International, 2024. store.astm.org/d1331-20r24.html (opens in a new tab) standard catalogue · accessed 2026-10-27
   Catalogue scope text only; full standard not read.
6. S6. ASTM D2578-17, Wetting Tension of Polyethylene and Polypropylene Films (ANSI webstore entry). ASTM International. webstore.ansi.org/standards/astm/astmd257817 (opens in a new tab) standard catalogue · accessed 2026-10-27
   Shown as historical; current edition not confirmed.
7. S7. ASTM D1894, Static and Kinetic Coefficients of Friction of Plastic Film and Sheeting (D1894-06 page listing D1894-24 as active). ASTM International, 2024. store.astm.org/d1894-06.html (opens in a new tab) standard catalogue · accessed 2026-10-27
   Catalogue page; full standard not read.
8. S9. ASTM D3359-23, Standard Test Methods for Measuring Adhesion by Tape Test. ASTM International, 2023. store.astm.org/d3359-23.html (opens in a new tab) standard catalogue · accessed 2026-10-27
   Catalogue listing shows D3359-23 as active (updated Mar 2023); full standard not read.
9. S10. ASTM D4541, Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers. ASTM International. www.document-center.com/standards/show/ASTM-D4541 (opens in a new tab) standard catalogue · accessed 2026-10-27
   Title from a standards-reseller listing; edition not read.

Regional manufacturing evidence

Company and trade publications cited in Manufacturing Regions & International Supply. Each supports only the statement it is cited for (checked 29–30 October 2026). Naming a company here does not state or imply a relationship with PAXOMER.

1. R02. Shin-Etsu Chemical invests in silicone (Gunma Complex, main silicones production base in Japan). CHEManager International. chemanager-online.com/en/news/shin-etsu-chemical-invests-in-silicone (opens in a new tab) checked 2026-10-30
2. R03. KCC silicone business and Daejuk silicone factory, Seosan. Asia Economy. www.asiae.co.kr/en/article/2024111515274449741 (opens in a new tab) checked 2026-10-30
3. R42. BYK production expansion completed in Shanghai (silicone additives). BYK (ALTANA). www.byk.com/en/company-news/news/detail/byk-production-expansion-successfully-co (opens in a new tab) checked 2026-10-30