fluorination improves the surface properties of · pdf filefluorination improves the surface...

Fluorination improves the surface properties of plastics

Job order productionfor your successLong-term stability

with no dimensional changes

Improved surface wettability

Reduced friction and stickiness

Better bonding and adhesion

Less permeation, diffusion and migration

Plastics are selected primarily according totheir mechanical and thermal properties,their suitability for processing and theirprice. Then, after careful selection, it’s oftenfound that the surface doesn’t meet require-ments. However, the surface is the only ma-terial property that can be changed inde-pendently. Very often, gas-phase fluorinationis the solution of choice.

Chemical reaction

Plastic surfaces are fluorinated by exposingthem to a fluorine mixture. Due to its highreactivity, fluorine partially replaces hydro-gen atoms in the material surface. Its prop-erties are modified mainly by the highersurface energy and the surface polarity.Systematic process control allows the resultof the fluorination process to be optimallyadjusted to the original polymer and thespecified application.

Fluorination is a chemical reaction, not acoating. Accordingly, fluorine atoms pene-trate the substrate’s molecular structure.The process doesn’t affect the properties ofthe base material, and its dimensions re-main unchanged.

Treatment processAll relevant treatment parameters are ad-justed to the product and the specific ob-jective of the treatment during a test phase.The values obtained are then applied as aformula for series production.The following relevant process parametersare controlled automatically and repro-ducibly:

• Fluorine concentration• Treatment duration• Process temperature

Non-fluorinated unpolar polymer chain

Fluorinated polar polymer chain

F

HF

F2

+ + +

+++

– – –

–––+ + +

Offline batch fluorination

Three-dimensional parts are treated in adiscontinuous process. They are pre-treatedin a vacuum chamber according to the for-mula specifically developed for the pur-pose. Small parts of only a few mm in sizeare fed into the cylindrical chamber as bulkmaterial. The cube-shaped chamber acceptslarger or mechanically sensitive parts incrates, grid boxes or transport units. Thesemay fill the chamber almost entirely.

Many industries

Significant new properties are created onthe surfaces of parts and materials, and of-ten more cost-efficient solutions can nowbe achieved without having to search for al-ternative materials or processing methods.Fluorination is successfully applied in manyindustries:

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

Fluorination at room temperature

Fluorination is the method of choice evenfor thermosensitive parts. The treatment isapplied at steady, low temperatures, usuallyat room temperature, avoiding local tem-perature peaks.

Component

Fluorine gas Residual

Component with activated surface

Inline web material fluorination

In an inline system, web material is fluori-nated in a continuous process. Treatmentresults are determined by throughput rateand fluorine concentration. The system isdesigned to treat a wide range of web ma-terials of varying thickness and widths ofup to b = 2.100 mm from roller to roller. Weprocess• Filter media• Films• Fabrics• Foams• Technical textiles• Non-woven fabrics

Long-term stability

The bond energy of the carbon-fluorinecompound created in the surface is extraor-dinarily high. Accordingly, the process offluorination is not reversible. The surfaceproperties achieved remain stable over longperiods.

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.This ensures a consistently high treatmentquality right down to the most remote cor-ner of the component.

30

40

50

Non-fluorinated

Source: Innovent e.V.

Sur

face

ene

rgy

[mN

/m]

Direct 1 month 3 months 6 monthsStorage period

PP Total energy

Web material

Fluorine gas Residual

Web material with activated surface

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. Fluorination can be applied to all plastics: ABS, EPDM, plasticsmade of renewable raw materials, NBR, HNBR, PC, PEEK, PMMA, polyamide, polyester, glass fibre-re-inforced polymers, mixed polymers, polypropylene, silicone, TPE, etc.

Better properties in practice


Wettability fluorination

Smoother fluid filmsand faster drying

Fluorination hydrophilises sur-faces, enhancing coating qualitythrough better wetting, film for-mation and adhesion properties.This yields significant savingswhen painting, printing or ap-plying decor to the surface. Asmoother water film also meansmore even drying, a higher printquality and less lime and mouldformation.

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 adhere 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


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.




Objectives

Non-fluorinated Fluorinated

Optimal paints Durable adhesive bonds

Consistent film formation Stronger bonding

Improved wetting(hydrophilic properties)

Increasedsurface energy

Fluorination

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

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

Wettability fluorination

Smoother fluid films and faster drying

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

Adhesion fluorination


Hydrophilic filter material

Faster-drying appliances

Enhanced print adhesion

Perfect paint layers in critical areas

Dripping behaviour of PS tubes

Capillary effect of filter material

Grid-cut testing of paint adhesion to substrate

Adhesion of flocking material to substrate



Examples of treated products

Non-fluorinated Fluorinated0

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]


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.

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.

Silicon

eRub

ber

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




Adhesion of a label with and without the effect of diffusing contents

Diffusion of ingredients

Soiling behaviour of silicone

Rubber doesn’t stick – without talcum or silicone oilO-rings are easy to separate and install

Non-sticking profiled seals

Diffusion-proof containers for chemicals

Diffusion-proof dispensers

Examples of treated products

The FTS service offeringfor surface finishing

Tests and pre-production series

Each new treatment is subject to a seriesof tests, adjusting it to the product anddefining the optimal parameters that arethen saved as the formula. Our customersare welcome to participate in the testingprocess and to verify the new impact of thecomponent in its intended use. The param-eters used can be repeated reliably and willlater be applied in series production.

Series production

FTS can fluorinate small and medium pro-duction series, even if parts are highly di-verse:• Bulk material from 1 mm in size• Components in racks and transport units

up 1.800 mm in size• Web material up to a width of 2.100 mm

FTS is specialised in fluorination with 25years experience in the field. Our high levelof competence is based on our highly qual-ified personnel and our equipment fleet,which is maintained to the latest techno-logical standards by our in-house plant en-gineering department. Regular participationin research projects ensures that we keepabreast of state-of-the-art technology, andunderlines our position as a developmentleader.

Process development

FTS changes the properties of plastics insuch a way that specified functions areachieved in an optimal manner: adhesion,sliding, wetting and barrier formation areoptimised. The components' dimensionsand physical properties remain unchanged.FTS identifies the possibilities and also thelimits of the fluorination process.


Service

Our customers from many industries appre-ciate our quick and uncomplicated commu-nication. FTS offers any service you mayneed:• Analytical investigations• Individual, customised packaging• Storage of intermediate and finished

products• Just-in-time delivery on call• Quick and uncomplicated order process-

ing• Individual labelling and identification

Quality management

We are certified according to DIN EN ISO9001:2008 by the TÜV CERT certification of-fice of TÜV Hessen, certificate no. 73 100 145.• We apply defined parameter sets. These

are defined together with the customeraccording to the product and its use dur-ing sample evaluation and are stored asa formula in the PLC.

• The process of fluorination is fully auto-mated. Deviations from target values areidentified and signalled. The entire pro-cedure is documented.

• Surface tension is measured using testink according to DIN ISO 8296.

• Initial-sample test reports and test cer-tificates are generated upon request.

Wettability fluorination Anti-friction fluorination Adhesion fluorination Surface barrier fluorination




Benefits of gas-phase fluorination

• Long-term stabilityDepending on the material, the effects achieved onthe surface remain stable for several months.

• Even application with no geometric constraintsEven deep grooves, undercuts or cavities with smallopenings are pre-treated consistently. All exposedsurfaces have identical properties.

• ReproducibilityThe fully automated procedure facilitates easy con-trol and monitoring of influencing factors, allowingthe exact result to be replicated later on.

• Low temperaturesThe treatment is performed at low temperaturesthat doesn't affect the plastic material. Local temperature peaks are avoided.

• Antibacterial effectFluorination has an antibacterial effect for a limited period.

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' individualrequirements. We utilise our extensive ex-perience in plant engineering and opera-tion – from planning and construction toinstallation and commissioning.

Plant engineeringFTS 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. Please feelfree to inquire.

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.

Fluor Technik System GmbHAltebergstraße 27–2936341 Lauterbach, GermanyPhone +49 (0) 6641 9685 0Fax +49 (0) 6641 9685 [email protected]

Fluor Technik System GmbH

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