Gas-phase fluorinationsystems

Project planningPlant engineeringService

Fluorination of plastics for enhanced surface properties

• High-performance technology• Easy to operate• Comprehensive application know-how

Improved surface wettability

Reduced friction and stickiness

Better bonding and adhesion

Less permeation, diffusion and migration

Plastics are selected primarily according to their mechanical and thermal properties, their suitabilityfor processing and their price. After careful selection, it’s often found that the surface doesn’t meetrequirements. However, the surface is the only material property that can be changed independently.Very often, gas-phase fluorination is the solution of choice.The fluorination process enhances many surface properties. It is highly effective in modifying the topmaterial layer without adversely affecting the properties of the underlying material. No other methodcan achieve such a targeted effect.

Wettability fluorination

Smoother fluid filmsand faster drying

Fluorination hydrophilises sur-faces, enhancing coating qual-ity through better wetting, filmformation and adhesion prop-erties. This yields significantsavings when painting, printingor applying decor to the sur-face. A smoother water film alsomeans more even drying, ahigher print quality and lesslime and mould formation.

Anti-friction fluorination

Reduced friction, sticki-ness and clinging

The stickiness of elastomercomponents made of NBR,HNBR, EPDM or other types ofrubber and silicone is reducedto a minimum. Talcum, siliconeoils or other additives are nolonger required. These proper-ties are long time stable even ifthe material is regularly cleanedor sterilised. Contaminantsdon’t attract to the surface, soparts remain clean.

Adhesion fluorination

Better bonding andadhesion

Fluorination can improve theadhesion properties of plasticmaterials. The polarity of thesurface is increased, therebyimproving adhesion and wet-ting. Lamination lasts longer,flocking is more durable, andthe bonding of adhesives is im-proved.

Surface barrier fluorination

Less permeation, diffusion and migration

This type of fluorination createsa barrier against non-polar sub-stances, reducing permeation,diffusion and migration of short-chain fluids (solvents, petrol,coolants, glycerol, etc.) to a min-imum. Additives of the plasticmaterial no longer diffusethrough the surface, and ele-ments of the container filling nolonger permeate the wall.

Fluorination enhances product properties

Chemical reaction

Plastic surfaces are fluorinated by exposing them to a fluorine mixture. Due to its high re-activity, fluorine partially replaces hydrogen atoms in the material surface. Its propertiesare modified mainly by the higher surface energy and the surface polarity. Systematicprocess control allows the result of the fluorination process to be optimally adjusted to theoriginal polymer and the specified application.

Fluorination is a chemical reaction, not a coating. Accordingly, fluorine atoms penetrate thesubstrate’s molecular structure. The process doesn’t affect the properties of the base ma-terial, and its dimensions remain unchanged.

Non-fluorinated unpolar polymer chain

Fluorinated polar polymer chain

F

HF

F2

+ + +

+++

– – –

–––+ + +

Improved surface wettability

Reduced friction and stickiness

Better bonding and adhesion

Less permeation, diffusion and migration

Offline batch fluorination

Three-dimensional parts are treated in adiscontinuous process. They are pre-treated in a vacuum chamber according tothe formula specifically developed for thepurpose. The following materials can beused:

• Plastics• Caoutchouc• Rubber• Silicone• Elastomers• Plastics made of renewable raw materials

Inline web material fluorination

Fluorination is often used to make web ma-terial hydrophilic before coating, applyingadhesive, painting, etc. The material is fedcontinuously into the treatment chambervia a gate system. After fluorination, the ma-terial leaves the chamber via a downstreamgate system and is rolled up.

• Filter media• Films• Fabrics• Foams• Technical textiles• Non-woven fabrics

Long-term stability

The bond energy of the carbon-fluorine com-pound created in the surface is extraordi-narily high. Accordingly, the process of flu-orination is not reversible. The surfaceproperties achieved remain stable over longperiods.

Fluorination at room temperature

Fluorination is the method of choice evenfor thermosensitive parts. The treatment isapplied at steady, low temperatures, usuallyeven at room temperature, avoiding localtemperature peaks.

Complex geometries

Gas-phase fluorination yields absolutelyconsistent application results. Cavities, un-dercuts, recesses and wraps, as well as tex-tured and coarse surfaces, are treated ho-mogeneously and without any shadowing.The result is consistent surface qualityacross all parts.

FTS develops and manufactures fluorination systems

Gas-phase fluorination is a dry method for treating surfaces. It is easy to use, and its repro-duction accuracy is high. The method can create many effects that aren’t possible with othermethods. The fluorination systems offered by FTS reflect the latest technological knowledge.They can be customised to meet individual requirements. Long-term stability and carefultreatment of the material are the characteristic features of fluorination, as are its environmentalcompatibility and cost efficiency.

Suitable for many industriesSignificant new properties are created on the surfaces of partsand materials, and often more cost-efficient solutions can beachieved without having to search for alternative materials orprocessing methods. Fluorination is successfully applied inmany industries:

• Automotive• Construction materials• Lighting• Print products• Electrical engineering• Filtration• Aerospace• Medical technology• Building services• Technical textiles• Tunnelling• Packaging• Household appliances

Offline fluorination Systems for three-dimensional substrates

Occupational safety

Fluorine is the most reactive element in the periodic system. Itsprocessing is subject to legal and other regulations pertaining tooccupational safety. Our systems process only fluorine mixtures oftype F2/N2 10/90, i.e. 10% fluorine and 90% nitrogen. To controlthese mixtures, we rely on type-approved valves and pressure reg-ulators that are implemented as redundant units.State-of-the-art technology has been used for many years to storeF2/N2 mixtures and to supply the fluorine. The threshold limitvalue (TLV) is monitored continuously for additional safety, andalarm and shut-down functions are triggered if required.

Offline systems apply fluorination to three-dimensional parts inbatch cycles: Shaped parts are fed into the vacuum chamber, fluo-rination is applied, and the parts are subsequently removed. Thevacuum chamber is the core of any offline fluorination system madeby FTS. It is optimised for the parts to be treated and for theirquantity, the transport units and the loading and unloading proce-dure. All systems come complete with vacuum pumps and fixtures,fluorine supply and removal equipment, and control and safety de-vices.

Diameter

400 600 1000 1600 2000

Custom dimensions availableupon request

Cube- or cylinder-shaped vacuum chamber

The cube-shaped chamber accepts larger or mechanically sensitiveparts in transport units or in loose arrangement. The cylindricalchamber accepts small parts as bulk material, moving them care-fully to ensure uniform fluorine exposure.

Treatment process

For fluorination, products in the vacuum chamber are exposed to afluorine/nitrogen mixture. Treatment duration, fluorine concentra-tion profile and process temperature are adjusted to the specificproduct and application characteristics. The parameters inside thechamber are homogeneous at all times. All parameters are testedin pre-production trials. They are stored as a formula in the PLCand can be reproduced reliably.

Opening

250 x 400 400 x 600 600 x 1000 1000 x 1600

Custom dimensions available upon request

Inline fluorination Systems for web material

Inline systems fluorinate web material in a continuous process.The material enters and exits the fluorination chamber via a gatesystem. Films, fabrics and foams of almost any origin and thicknesscan be processed. Inline fluorination systems from FTS comprise atreatment chamber and two gate systems incorporating a flushingzone. The systems come complete with vacuum pumps and fixtures,the fluorine supply and disposal system, and control and safetydevices. Unwinders and winders are available as options.

Environmental protection

Fluorination is an environmentally friendly way of pre-treating sur-faces:• to avoid waste-water flow,• to eliminate solvent-based paints and adhesives, and• to save energy thanks to low temperatures.

Fluorination systems do not emit any harmful substancesGas-phase fluorination is a dry chemical process neutralising the flu-orine mixture and the resulting byproducts directly within the process.Exhaust air is fed through an absorber containing calcium carbonategrit (CaCO3). Inside the absorber, the gas is converted into calciumfluoride (CaF2), also known as fluorspar, a frequently occurring mineralthat is non-toxic, environmentally neutral and non-water-soluble. Thecalcium carbonate absorber is designed to comply with current legallimits as well as any limits to be expected in the future.

2 F2

+ 2 CaCO3

2 CaF2

+ 2 CO2

+ O2

Material width and thickness

Inline systems are designed to the maximum width and thicknessof the material to be processed. The material's maximum length isdetermined by the choice of winder.

Treatment process

For fluorination, products in the vacuum chamber are exposed to afluorine/nitrogen mixture. Treatment duration is defined by thelength of the active treatment section inside the chamber and thematerial feed rate. The fluorine concentration profile and processtemperature are adjusted to the products and the specified treat-ment results. The parameters inside the chamber are homogeneousat all times. Optical measurement in the UV range is applied tomonitor fluorine concentration. Any deviation from the target valueis compensated by a dosing and control valve system. All parame-

ters are trial-tested in advance and are stored as formulasin the PLC to ensure reliable repeatability.

Frequent applications

The following web materials are treated prior to prin-ting, coating, laminating or hydrophilising:

• Foams• Technical textiles• Fabrics• Films

Frame width

400 1000 2000 5000

Custom dimensions available upon request

Objectives

Process backgroundFluorination increases surface roughness,enlarging the contact surface and hence im-proving adhesive bonding. Adhesion fluori-nation is used whenever the application re-quires extensive and uniform layer bonding:increasing surface energy also improveswetting and film formation, as well as thebonding of paints and adhesives. When ap-plied as a pre-treatment, fluorination cre-ates absolutely consistent results, even incomplex geometries with undercuts, re-cesses or wraps.

Use• To apply paint, flocking or decor• To produce compound plastics• To bond plastics with other materials using

adhesive• To treat man-made and natural fibres• To pre-treat reinforcement fibres for com-

pounds

Three physical effects have a significantimpact on the bond between adhesives orpaints and the component. Fluorination canenhance these effects:

• Wetting• Film formation• Adhesion

Fluorination for better adhesion yields costbenefits.

• No primer is needed• Environmentally friendly water-based

paint can be used• More cost-efficient paint and adhesive

systems can be used• Fewer paint layers are needed

Process backgroundThe wetting properties of plastic materialsdepend on the polarity pairing: different po-larities cause the liquid to form drops onthe surface. Fluorination creates higher sur-face energies in polar plastics that are thusadjusted to the surface energy of the liquid.Such surfaces are very suitable for wettingwith polar liquids.

Use The larger and smoother surface of the liq-uid covering a component has the followingbenefits:

• Faultless liquid films• More uniform coating• Enhanced printability• Faster drying• Better draining of liquids• Prevention of mould formation• Improved lubrication effect of liquid

Wetting plastic surfaces is much easier afterthey have been fluorinated.

• Enhanced liquid films• More uniform layers• Improved drying• Smooth draining of liquids

Non-fluorinated Fluorinated

Surface energiesNon-fluorinated Fluorinated

(mN/M) (mN/M)

Polyethylen Low Density LDPE 32 54

Polyethylene PE-UHMW 37 54

Polypropylene PP 29 66

Polyoximethylene POM 40 72

Polyethylene PET 32 72

Ethylene propylene diene co-polymer EPDM 40 58

Polybutylene PBT 30 72

Polycarbonate PC 32 56

Polyphenylene sulfide PPS 32 60

Polysiloxan elastomer SI 32 54Source: Fluor Technik System GmbH

Adhesion fluorination

Better bonding and adhesion

Wettability fluorination

Smoother fluid films and faster drying

Optimal paints Durable adhesive bonds

Consistent film formation Stronger bonding

Improved wetting(hydrophilic properties)

Increasedsurface energy

Fluorination

Anti-friction fluorination

Reduced friction coefficient, stickiness and clinging

Friction forces on glass [N]Non-fluorinated Fluorinated

Formula 1 [N] Formula 7 [N]

LSR2650B 15.6 3.9 1.0

LSR2630B 10.1 6.3 0.7

FSL7651A 9.2 5.6 0.8

FVMQ 12 11 6

Silplus60Ex 9.2 2 0.8

NBR 9.2 5.5

PPE 8.5 4.2

EPDM 10.5 4.6Source: Innovent e.V.

Plastics are inherently permeable to cer-tain gases and liquids. This is why plasticcontainers lose some of their contents overtime. Such permeation causes odours andimpacts the environment. The weight andproperties of the contents change, and la-bels may peel off. Components migratingfrom plastic materials may change theproduct properties to an extent that causescomponent failure. Fluorination preventssuch adverse effects, and very often a morecost-efficient packaging material can beused.

Process backgroundFluorinated surfaces act like a barrier againstnonpolar substances. Inner and outer con-tainer surfaces modified by fluorination re-duce the permeation of short-chain solvents,coolants, glycerine and petrol. The diffusionof material components through and fromthe fluorinated surface is significantly re-duced.

Use• To reduce the the permeation of petrol and

diesel fuel from tanks of motor vehiclesand other equipment

• To limit the migration of softeners andother additives, preventing plastics frombecoming brittle

• To improve resistance to acidic and causticsolutions, preventing surfaces from swellingor becoming greasy

Surface barrier fluorination

Less permeation, diffusion and migration

Many components made of elastomers suchas NBR, HNBR, EPDM, silicone and otherrubbers have a dull surface. These are oftensticky and don’t slide well across other sur-faces. This may cause difficulties during as-sembly and adverse effects during use. Ad-ditives, talcum and silicone oils are oftenused as a remedy. Fluorination significantly reduces contam-ination by additives and avoids other dis-advantages. Fluorinated surfaces retaintheir properties over long periods evenwhen subject to regular cleaning and ster-ilisation. Reduced surface stickiness alsoreduces soiling, enhancing the components'visual appeal.

Process backgroundIntensive fluorination causes the fluorineatoms to be embedded in the surface. Sticki-ness and static and dynamic friction are sig-nificantly reduced. This effect is enhanced bythe inherent increase in surface roughnesswhile the rubber-specific properties remainunaffected.

Use• To minimise friction and soiling• To reduce creaking and crackling caused by

high static friction between rubber and mat-ing surfaces

• To reduce stick/slip effect in sliding motion• To facilitate assembly• To enhance visual appeal• To reduce stickiness: Release agents become

obsolete, parts are easier to separate, andparts subject to static load release withouteffort.

0

10

20

30

40

50

60

70

Mass loss [g]

Non-fluorinated

Fluorinated by FTS

Source: Innovent e.V.100 200 300 400 500 Storage period [h]

Silicone

Rubber

Non-fluorinated Fluorinated

FTS has focussed on the development andmanufacture of fluorination systems andfluorination services for more than 20 years.Realised projects, memberships in trade as-sociations, cooperation with universitiesand research institutes, as well as manypatents, are proof of FTS' expertise. We aremember of the Flock Association of EuropeFAoE e.V.

ConsultingFTS advises on actions, potential applica-tions and effects of gas-phase fluorinationof plastics and other materials. For optimalresults, FTS tests the treatment parametersin its own laboratory in close cooperationwith its customers.

Development and engineeringFTS develops and designs systems that arecustomised to our customers' individual re-quirements. We utilise our extensive expe-rience in plant engineering and operation –from planning and construction to installa-tion and commissioning.

Plant engineering FTS builds inline and offline systems forgas-phase fluorination, adjusting themspecifically to the requirements defined bythe product or operation. Ancillary systemssuch as fluorine supply, calcium carbonateabsorber and work safety devices are in-cluded in the equipment design.

ServiceFTS offers a full range of services: from op-erator training and routine maintenance tosystem extension and conversion. We sup-port the approval and certification of thesystems.

Job order productionFTS refines the surfaces of supplied prod-ucts for further processing and installation:bulk material, products placed in transportunits, web material, etc.Please feel free to inquire.

Fluor Technik System GmbHAltebergstraße 27–2936341 Lauterbach, GermanyPhone +49 (0) 6641 9685 0Fax +49 (0) 6641 9685 50info@fts-de.comwww.fts-de.com

Korfl

ür M

arbu

rg D

R xx

031

4 01

2

Fluor Technik System GmbH