minimal application tech

Minimal application systemsAlternatives to padding processes in continuous textile finishing

Textile Effects

Minimal application systems

Target of minimal application

Reduce liquor pick-up compared to padding processes (60 90 %) on a level of 30 50 % resulting in

Less energy consumption Higher productivity due to higher production speed Less migration of finishing liquor Lower water consumption

Lower pick-up has to be compensated by higher bath concentration of finishing products

Textile Effects

Liquor pick-up in Finishing

%10 20 30 40 50 60 70 80 90 1000 110

Padding of woven goods

Padding of knit goods

Foam Finish

Weko humidification

Not suitable for textile finishing

Potential energy saving in water evaporation

Minimal application Conventional application (padding) independent on fiber/fabric

Textile Effects

Application systems in textile finishing

Pad application

Most universal application equipment No limitation in continuous finishing Affinity to substrate not desired in order to

avoid tailing effects

Comparatively high liquor pick-up of 60 90 % Resulting in lower drying efficacy9 Therefore minimal application technologies to be developed

Textile Effects

Dip-spin application Alternative to pad application No affinity of chemicals desired Affinity will create tailing if bath is used

several times

9 Re-use of bath is necessary due to cost reasons This is not an exhaust process Finishing bath added in a liquor ratio of approx. 8:19 After treating during approx. 5 min. bath is pumped back to

be re-used

Can be used during 1 shift if filtered to get rid of fibers and fluffs

Application systems in textile finishing

Textile Effects

Garment Manufacturing Washer (dip spin application)

Tumbler

Topper

Steam PressCuring Unit

Dip spin or spray process on garments

Textile Effects

Basic principle of minimal application Mechanical tools to reduce liquor pick-up Kiss-roll application Spray application Vacuum exhaustion (mainly on synthetics with low swelling) Muwa spray system

Dilution of finishing products by air instead of water (Application of instable foam) Stork CT system via rotary screen Texicon Monforts Vacu Foam (denim finish) Foam padding Foam knife on air application


Less important for textile finishing

Textile Effects

Kiss roll application

Done on one side only by roller, mainly for realizing single sided effects

Usually done on reverse side Hydrophilic finish, pigments,

stiff finish

Viscosity of bath can be increased by thickener

Engraved roller can be used if higher concentration is desired locally (e.g. for hot melt application)

Lower pick-up to be compensated by higher product concentration


Finishing liquor

Engraved roller

Textile fabric

Textile Effects

Minimal application technologiesSpray application (Weko spraying system)

Spraying done by centrifugal force Two systems necessary for face and backside Finishing products have to Provide a high mechanical stability

as high shear forces do occur

Provide a low foam tendency Should not create a film as this

might block spray nozzles

Be emulsifiable in aqueous systems for cleaning the nozzles

Formation of aerosols to be considered requiring an enclosed system with good air extraction

Textile Effects

Minimal application technologies

Vacuum technology

Can be used with or without padder decreasing liquor pick-up

Only suitable for synthetic fabrics providing low swelling with tight construction allowing good efficacy of vacuum

Water absorbed by swelling (e.g. on cellulose) cannot be removedby vacuum

Sucked off finishing liquor cannot be re-used again due to potential contamination with fibrous material

Saving of chemicals can therefore not be realized Only suitable to reduce drying energy on synthetics

Textile Effects

Finishing with instable foam

Dilution of finishing products done by air instead of water

Addition of foaming agent required Foam stability of 1 - 3 min. required

(time before first drop is created)

Too stable foam would create foam spots after drying Too instable foam would de-water before application

Foam weight of approx. 100 140 g/l to be adjusted Liquor pick-up of 30 50 % realistic


Textile Effects

Checking of foam parameters in lab

Foam to created on Kenwood mixer with 300 ml liquor at full speed

Check foam weight be filling in plastic cup with 100 ml (target 100 140 g/l)

Check foam stability by turning cup filled with foam, first drop should drain off after 1 3 minutes

Check half-life after putting 1 l of foam in plastic cup

50 % of contained liquor shoulddrain off after > 30 minutes


Textile Effects

Minimal application systemsFinishing products suitable for foam application with DICRYLAN FOAMER HP

Product group Range name Rating

Antistatic agents ZEROSTAT +++

Anti-slipping agents FORNAX +++

Cross-linking resins KNITTEX +++

Softeners SAPAMINE +++

Polyethylene TURPEX Might be difficult in combination with silicone

Silicone ULTRATEX Might be difficult with silicone macro emulsions

Fluoro-chemicals OLEOPHOBOL Amount of foaming agent not to be exceeded

Polymers DICRYLAN +++

Flame retardant FLOVAN PYROVATEX

+++

Biocidal finish SILPURE +++

Textile Effects


Finishing product

Water

Finishing product

Water

Given bath concentration related to same product add-on

Pad application with 70 % liquor pick-up

Foam application with 35 % liquor pick-up

Reduced liquor pick-up

Amount of water Amount of water to be saved to be saved during dryingduring drying

Proportional two-dimensional demonstration

Textile Effects


Dilution of finishing liquor by air

Dilution factor approx. 7-10

Resulting in a foam weight of 100 140 g/l

Foam stability of 1 - 3 min. before dewatering is starting

Foam creation done by foam generator with stator / rotor device

Before foaming After foaming

Increased volume by dilution with air

Textile Effects

Foam structure

Aqueous finishing liquor

Air

Air

Surfactant foaming agent

Hydrophobic part

Hydrophilic part

Textile Effects

Foam structure

Finishing liquor

Hydrophobic end

Hydrophilic end

Timing of foam collapsing important

Too early de-watering might cause spots

Foam collapsing after starting drying might cause foam spots

Collapsing foam will wet textile fabric with finishing liquor

Textile Effects

Finishing with instable foamFoam application

System with good penetration preferred e.g. Stork CT by Rotary Screen Foam (RSF) application

Ensures good penetration of foam into fabric to be finished Pressure of 2.0 5.4 atm. given by foam generator transferred to textile Foam will immediately collapse after application9 Avoiding foam spots after drying

Textile Effects


Closed system


Open system

Foam coating with stable foam

Textile Effects

Principle of foam generator

1

2

3

4

5

6

4a 4b

Foam generated by high mechanical stress (stator/rotor) while feeding with A defined amount of air with a certain pressure A defined amount of finishing liquor

1 Finishing liquor 2 Air pressure 3 Air flow meter

4 Mixer 4a Stator 4b Rotor

5 Foam pipeline 6 counter pressure (system pressure)

4a

4b

Textile Effects

12

34

5

6

7


Stork CT 4 application system

1 Knife

2 Plastic profile

3 Pneumatic pressure hull

4 Protection blade

5 Foam feeding pipeline

6 Perforated rotary screen

7 Textile fabric

Foam pressure created by foam generator is directly transferred to textile fabric allowing good penetration

Foam

Textile Effects

Foam application parameters

Finishing products have to be foamable on required stability

Foam weight of 100 140 g/l De-watering starting after 1 - 3 min.

Foaming agent must not impair effects like oil- and water repellency Some products are difficult to foam (e.g. silicone macro emulsions) Foam stability can be increased by slightly increasing viscosity Might impair product penetration

Penetration might be insufficient in case of adding optical brighteners (potential double side effect)


Textile Effects

Requirements to instable foam used for finishing

Target Characteristic

Homogeneous character Uniform, fine pored

Degree of foaming Adjustable, foam weight of 100 140 g/l desired

Foam stability Low, dewatering to start after 1 - 3 minutes (first drop) but not before application

Dewatering Quick, to start immediately when contacting textile fabric


Textile Effects

Foam finishingAdvantages versus padding processes

Approx. 50 % saving of drying energy due to lower pick-up Higher productivity as a lower amount of water to be evaporated Almost no migration during drying Migration usually does not occur on a pick-up level below 30 -40 % Drying can be started at higher temperatures with higher efficacy

Textile Effects

Foam application

Limit of foam application

Padding with 300 g/l of product

Foam application with 600 900 g/l for getting same add-on

Foam application comes to its limit if a product concentration of approx. 300 g/l by padding has to be exceeded

product Product triple conc.

Product double conc.

waterwater water

Lower add-on to be compensated by 2-3x higher product concentration

Foaming liquor

Textile Effects

Foam application


Flame retardant finish

Product concentration of 400 g/l frequently exceeded in pad application

Might cause difficulties to create the desired foam, especially if high amount of silicone macro emulsions are contained

Very high product concentration for foaming might increase bath viscosity having an influence on foam stability

9 Higher viscosity usually increases foam stability9 Foam might collapse too slow and not yet before drying

starts resulting in foam spots on dried fabric

Textile Effects

Foam application


Application of optical brighteners by foam

Might cause double side effects due to insufficient migration offinishing liquor

Problem is more severe if shading dyes are addedwith extremely low bath concentration

In case of adding optical brighteners it is recommended to increase liquor pick-up

This however reduces the advantages versus pad application which is the reason that many finishers refrain from applying FWAs by foam and prefer pad application

Textile Effects

Foam application

Limits of foam application

Potential impact of foaming agent

Might cause compatibility issues due to ionic character9 Amphoteric DICRYLAN FOAMER HP is preferred being

compatible both with anionic, cationic and nonionic systems

Influence of water and oil repellency to be considered9 Issue with anionic and nonionic surfactants, good results with

DICRYLAN FOAMER HP if recommended amount is not exceeded

Textile Effects

Foam application


Construction of textile fabrics to be finished

Tightly woven, heavy weight articles might show problems to enable a sufficient penetration

9 This might be true for work-wear based on twill, canvas, atlas or other constructions

Penetration could be increased by9 Choosing a higher pick-up9 Working with an application device applying foam

on face- and backside

Textile Effects

Foam finishing


Process parameters - Liquor pick-up A liquor pick-up below 30 % does usually not result in an

equal distribution of the applied finishing liquor

9 This is especially true for textile substrates with high swelling like e.g. viscose material

A liquor pick-up above 40 50 % decreases the cost advantage in process versus pad application

9 Taking into consideration the higher investment for foam application and the amortization a liquor pick-up of 40 -50 % should not be exceeded

Textile Effects

Foam finishing


Process parameters insufficient foam stability The foam stability requiring a dewatering starting

after 1-3 min. might be too low

9 Especially if certain silicone macro emulsions are added Poor emulsification quality will provide residues of

silicone oil destabilizing foam stability

9 Foam stability can be increased by slightly increasing bath viscosity adding low amount of DICRYLAN THICKENER X (1-3 g/l)

Textile Effects

Foam finishing


Potential Environmental Health & Safety issues Due to low pick-up the drying capacity of the stenter after

application is very high resulting in high productions speed

The rotary screen will therefore work with a high number of revolutions

The screen after passing the application slot will still containsome finishing liquors which might be transferred into an aerosol due to high centrifugal force

9 These potential aerosols have to be extracted by suction in order to avoid inhalation

Minimal application systemsMinimal application systemsLiquor pick-up in FinishingApplication systems in textile finishingSlide Number 5Slide Number 6Minimal application systemsMinimal application systemsMinimal application technologiesMinimal application technologiesMinimal application technologiesMinimal application technologiesMinimal application systemsMinimal application systemsFinishing with instable foamFoam structureFoam structureFinishing with instable foamSlide Number 19Principle of foam generatorFinishing with instable foamFinishing with instable foamFinishing with instable foamFoam finishingFoam applicationFoam applicationSlide Number 27Foam applicationSlide Number 29Foam finishingSlide Number 31Slide Number 32

minimal application tech

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