Graphics Arts Surfynol Surfactants Superior Substrate Wetting Agents

Surfynol® Surfactants: Superior SubstrateWetting Agents in Water-Based Printing Inks

Introduction

The performance benefits of Surfynol surfac-tants have been evaluated in water-based inksto assess their effectiveness in providingsubstrate wetting while reducing or eliminatingthe need for alcohols. The substrates evalu-ated were difficult-to-wet polypropylene andpolyethylene films as well as flexible paperand coated stock. The results demonstratethat Surfynol SE-F, Surfynol 420, Surfynol 440and Surfynol 104 surfactants provide impor-tant benefits, including:

• excellent substrate wetting and improvedflow and leveling;

• VOC reduction through solvent reductionor elimination;

• antifoam/low foam; and

• broad FDA compliances (for specificinformation, call 800-345-3148).

Additionally, the study results indicate thatSurfynol surfactants have no adverse effect ongloss, water sensitivity, blocking or flexo-graphic plate swell.

A summary of surfactant recommendationsand use-levels for typical printing ink applica-tions is provided in Table 1. Typical physicalproperties of Surfynol SE-F, Surfynol 420,Surfynol 440 and Surfynol 104 surfactants arepresented in Table 2.

Table 2

Typical Properties

Surfynol Surfynol Surfynol Surfynol 104SE-F 420 440 50% Blends1

Specific Gravity @ 25°C 0.971 0.943 0.982 0.839–0.999

Density, lb/gal 8.1 7.9 8.2 7.0–8.3

Viscosity @ 20°C, cps <200 <200 <200 <200(Brookfield, Spindle #3)

HLB (Hydrophile- 4–5 4 8 4Lipophile Balance)

1Surfynol 104 surfactant is available as a 50% solution in isopropanol, n-propanol, dipropylene glycol monomethylether (DPM), propylene glycol, ethylene glycol, 2-butoxy ethanol (EB) and 2-ethylhexanol.

Table 1

Surfynol Surfactant Starting-Point Recommendations

Surfynol Surfynol Surfynol Surfynol 104 IPASubstrate SE-F 420 440 50% Blends1 Comparison

Polypropylene 1% + 3–5% 1% + 3–5% 1% + 3–5% 1% + 3–5% 10%Film alcohol alcohol alcohol alcohol

Polyethylene 1% + 3% 1% + 3% 1% + 3% 1% + 3% 10%Film alcohol alcohol alcohol alcohol

Coated Stock 1% 1% 1% 1% 2%

Flexible Paper 1% 1% 1% 1% 2%

Other Selection Criteria

VOC, wt% 40 28 4 60–87 100%

Foam Control Excellent Excellent Good Excellent Excellent

Water Resistance Excellent Excellent Good Excellent Excellent

Excellent Good

1Surfynol 104 surfactant is available as a 50% solution in isopropanol, n-propanol, dipropylene glycol monomethylether (DPM), propylene glycol, ethylene glycol, 2-butoxy ethanol (EB) and 2-ethylhexanol.

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Surface Tension and VOC Reduction

Water-based printing inks have inherently highsurface tensions due to the surface tension ofwater (72 dynes/cm). To reduce surface ten-sion and achieve good surface wetting withdefect-free printing, solvents such as isopro-panol (IPA) are often incorporated. Increasingconcerns about Volatile Organic Compound(VOC) levels, however, require many formula-tors to reduce their use of solvents. Surfac-tants, as a result, have become an even moreimportant component in water-based inkformulations.

Typical surface tension values, such as thoseobtained with a DuNouy ring instrument, areequilibrium measurements that characterize asystem at rest. These values, however, are notindicative of an ink’s ability to wet out a sub-strate under dynamic or high-speed printingconditions. Indications of high-speed printingperformance can more accurately be predictedby measuring dynamic surface tension with aninstrument such as a maximum bubble pres-sure tensiometer.

Low dynamic surface tension occurs when asurfactant has the ability to migrate rapidly tothe newly created ink/substrate interface.Typical surfactants, however, generallyprovide good equilibrium values, but poordynamic performance. Most commercial sur-factants also tend to stabilize foam. Surfynolsurfactants, in contrast, provide high perfor-mance under both equilibrium and dynamicconditions while minimizing foam. Theseproperties make Surfynol surfactants excellentalternatives to solvents used in water-basedinks for substrate wetting and improvedprintability.

Substrates

Surfynol surfactants were evaluated in thefollowing flexographic and gravure printing inkapplications:

• Polymer film substrates for flexiblepackaging

– Polypropylene

– Polyethylene

• Paper substrates suitable for flexible pack-aging, folding cartons, food containers andpreprint linerboard

– Flexible paper (C1S)

– Coated stock

The ink systems were evaluated for equilib-rium and dynamic surface tension, ink print-ability, foam control, gloss, water sensitivity,blocking, film adhesion and flexographicphotopolymer plate swell.

Formulating Notes

Use-levels that include combinations ofSurfynol surfactants with reduced levels ofalcohol were selected as starting point recom-mendations for the polymeric film applications.However, Surfynol surfactants allow the for-mulating latitude required to balance thecompeting needs of performance, cost con-tainment and VOC reduction. For instance,Surfynol surfactants can be utilized at lessthan 1% use levels as a co-surfactant with theremaining alcohol. Alternatively, Surfynolsurfactants can be used as a total replacementfor alcohol at 2–3% for polymeric film applica-tions and 1% or less for paper substrates.

A common problem with many surfactants isthat they cause the ink viscosity to rise. If arise in viscosity occurs with the use of aSurfynol surfactant, introducing the surfactantat an early stage of the letdown with goodmixing is recommended.

Summary and Recommendations

Surfynol surfactants demonstrate the ability toprovide excellent substrate wetting and overallsystem VOC reduction in water-based inkformulations. These results are due to theirunique combination of low dynamic surfacetension and defoaming characteristics. Inaddition, Surfynol surfactants have no deleteri-ous impact on the other ink properties tested.The results reported in this study with isopro-panol have been observed with other commonsolvents, such as n-propanol.

Please refer to Table 1 for assistance in select-ing Surfynol surfactants. The starting pointrecommendations in Table 1 are based on theprintability results discussed in this brochure.In addition, various performance criteria arelisted in the table to further aid formulators inselecting appropriate Surfynol surfactants fortheir particular ink systems.

Performance Results

The data and results from the study are pre-sented on the following pages. Experimentalprocedures for all systems tested are outlinedin the Appendix of this brochure.

Flexible Polypropylene Film Inks

Two model water-based flexographic inkformulations, suitable for printing polypropy-lene flexible packaging films, are provided inFigures 1 and 2.

Figure 1 provides the equilibrium and dynamicsurface tension results of ink formulation 1,with and without Surfynol surfactants. A strongcorrelation can be seen between dynamicsurface tension reduction and the printabilityof the inks on polypropylene. This is demon-strated both photographically and through arating system. Here, Surfynol surfactants (withSurfynol SE-F and Surfynol 420 the mostnoteworthy) provide equal or superior print-ability at a 70% reduced alcohol level com-pared to the isopropanol-containing control.

Ink formulation 2 (Figure 2) was evaluated onan alternative polypropylene to demonstratethe broad-based performance of the Surfynolsurfactants. Surface tensions were againdetermined on the inks, both without surfac-tant and with combinations of surfactant and50% reduced alcohol. Printability, as with theearlier system, improves as dynamic surfacetension is reduced. Surfynol SE-F andSurfynol 420 surfactants, followed closely bySurfynol 104 and Surfynol 440, again demon-strate outstanding wetting properties.

Figures 1 and 2 also demonstrate foam controlperformance for the ink systems. The 10%alcohol control acts as an antifoam, preventingfoam formation, which results in higher inkfoam densities. This performance is readilyachieved with the Surfynol surfactant systemswithout the use of defoamers required withtypical surfactants. Surfynol surfactants areunique in this balance of surface tensionreduction and low foam, making themideally suited for water-based printinginks.

Other ink performance properties such asgloss, water sensitivity, blocking, adhesionand plate swell were evaluated with and with-out Surfynol surfactants. The results, providedin Table 3, clearly demonstrate that the addi-tion of Surfynol additives does not adverselyimpact other ink properties.

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Figure 1

Flexographic Ink for Polypropylene Flexible Film

Formulation 1

No Alcohol With With SurfynolModel Formulation No Surfactant Isopropanol Surfactant

Acrylic Polymer Emulsion1 44% 40% 40%

Acrylic Resin Solution2 11 10 10

Flexiverse Phthalo Blue GS 40 36 3615:3 Dispersion

Isopropanol — 10 3

Surfynol Surfactant (actives) — — 1

Water 5 4 10

100% 100% 100%

All inks adjusted to 25 seconds (#2 Zahn cup).Polypropylene Film: LBW 240 (ICI Americas Film Division); 33–36 dynes/cm (critical surface tension estimate).

Excellent Wetting and VOC Reduction with Surfynol Surfactants3

Excellent Foam Control with Surfynol Surfactants

1Vancryl® 954 (Air Products and Chemicals, Inc., Polymer Chemicals Division). Other choices include Joncryl 74 (S.C. Johnson Polymer) and Lucidene 603 (Morton International).2Vancryl 68S. Other choices include Joncryl 61 and Morcryl 134 (Morton International).3Photos taken at 3.7x magnification.

No IPA 10% IPA 3% IPA + 1% 3% IPA + 1% 3% IPA + 1% 3% IPA + 1%No Surfactant Control Surfynol SE-F Surfynol 420 Surfynol 440 Surfynol 104

Printability Rating(1 = Poor; 10 = Excellent) 2 9 10 10 9 9

Alcohol Replacement (wt %) — 0% 70% 70% 70% 70%

Dyne

s/cm

25

35

45

EquilibriumDynamic

Surface Tension69.7

35.2

42.8

31.8

36.1

32.7

37.6

34.7

38.7

33.1

38.042.5

Ink

Dens

ity (g

/ml)

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.52

0.84

0.72 0.75 0.71

0.83

No IPANo Surfactant

10% IPAControl

3% IPA + 1%Surfynol SE-F

3% IPA + 1%Surfynol 420



Unagitated Ink

- - - -

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Figure 2

Flexographic Ink for Polypropylene Flexible Film

Formulation 2



Flexiverse Diarylide AAOT Yellow 14 Dispersion 43 39 39

PE Wax Emulsion2 5 5 5



Water 5 4 8

100% 100% 100%

All inks adjusted to 25 seconds (#2 Zahn cup).Polypropylene Film: Bicor BSR-ONE (Mobil); 34–38 dynes/cm (critical surface tension estimate).



1Joncryl 624. Other choices include Lucidene 605.2Jonwax 26 (S.C. Johnson Polymers).3Photos taken at 3.7x magnification.




Ink

Dens

ity (g

/ml)

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.56

0.89 0.87 0.87

0.73

0.88

No IPANo Surfactant

10% IPAControl





Unagitated Ink

- - - -

Dyne

s/cm

25

35

45

EquilibriumDynamic

Surface Tension70.9

36.3

43.4

31.7

35.532.0

35.934.3

37.6

33.236.1

44.7

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Flexible Polyethylene Film Inks

A model flexographic ink suitable for printingpolyethylene flexible packaging films is pro-vided in Figure 3. The experimental results(Figure 3) again indicate a strong correlationbetween the dynamic surface tension of theink and printability on the polyethylene sub-strate. In addition, the photographs and sub-jective printability ratings clearly demonstratethat a 70% reduction in alcohol in combinationwith 1% Surfynol SE-F, Surfynol 420 orSurfynol 440 surfactant provides superiorwetting performance compared to the 10%isopropanol-containing control.

Foam control performance is also presented inFigure 3. Low foam is obtained with the con-trol ink containing 10% alcohol. Yet, similarfoam control performance is obtained in theformulation with a 70% alcohol reduction andthe addition of 1% Surfynol surfactant. Hereagain, Surfynol surfactants demonstratetheir defoaming and outstanding surfacetension reducing capabilities, making theman excellent choice when formulating inksfor polyethylene and other nonporous,difficult-to-wet surfaces.

Other ink performance properties, such asgloss, water sensitivity, blocking, adhesionand plate swell, were investigated with andwithout Surfynol surfactants. As seen with thepolypropylene inks, the results provided inTable 3 clearly demonstrate that there are nodeleterious effects with the addition ofSurfynol surfactants.

Coated Stock and Flexible Paper Inks

Inks formulated for porous substrates occa-sionally require wetting agents to assure wet-out and defect-free coverage. Surface defectsthat may require wetting agents include mot-tling and “snowflakes,” both of which arerelated to poor flow and leveling. Surfynolsurfactants can solve these problems, whileallowing the removal of alcohol and theirVOCs.

A model formulation suited for flexographiccoated stock ink and gravure flexible paper inkapplications is presented in Figure 4, alongwith test results. As with the flexographic filmink systems, a strong correlation can be seenbetween the dynamic surface tension values ofthe ink and printability on the substrates. Theaddition of 2% isopropanol reduces the dy-namic surface tension enough to allow moder-ate printability. However, when the isopropanolis replaced by 1% Surfynol surfactant, thesurface tension reduction and printabilityimproves significantly. Surfynol 420 andSurfynol 104 provide the best results on thecoated stock, while Surfynol SE-F, Surfynol420 and Surfynol 104 perform best on theflexible paper substrate.

The foam control data in Figure 4 indicatesthat the Surfynol surfactants provided similaror superior defoaming performance whencompared to the isopropanol-containingcontrol.

As illustrated in the polymeric film applicationareas, the unique combination of dynamicsurface tension reduction and defoamingcapabilities also makes Surfynol surfac-tants ideally suited for water-based inksfor porous substrates.

Gloss, water sensitivity, blocking, adhesionand plate swell were also evaluated with andwithout Surfynol surfactants. The results inTable 3 indicate there are no adverse effectson ink performance with the addition ofSurfynol surfactants.

Table 3

No Detrimental Effects with Surfynol Surfactants(Results for All Ink Formulations)

Gloss <1.5% variance with the IPA-containing control

Water Sensitivity No difference from the IPA-containing control

Blocking No difference from the IPA-containing control

Substrate Adhesion No difference from the IPA-containing control

Flexographic Plate Swell <1.5% weight gain over the IPA-containing control

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Figure 3

Flexographic Ink for Polyethylene Flexible Film



Flexiverse Diarylide AAOT Yellow 14 Dispersion 43 39 39

PE Wax Emulsion2 5 5 5



Water 5 4 10

100% 100% 100%

All inks adjusted to 25 seconds (#2 Zahn cup).Polyethylene Film: High Density, Corona Treated (Mobil); 32–35 dynes/cm (critical surface tension estimate).



1Joncryl 624. Other choices include Lucidene 605.2Jonwax 26.3Photos taken at 3.7x magnification.




Dyne

s/cm

25

35

45

EquilibriumDynamic

Surface Tension69.5

38.143.6

31.4

37.2

30.4

36.7

32.0

38.5

31.8

37.9

47.8

Ink

Dens

ity (g

/ml)

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.50

0.87 0.88 0.89

0.79

0.89

No IPANo Surfactant

10% IPAControl





Unagitated Ink

- - - -

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Figure 4

Ink for Coated Stock and Flexible Paper



Acrylic Resin Solution2 15 15 15

Flexiverse BFD-1121 30 30 30

Isopropanol — 2 —


Water 10 8 9

100% 100% 100%

All inks adjusted to 25 seconds (#2 Zahn cup).Coated Stock: Clay-coated Linerboard (Riverwood), Flexographic Printed; Flexible Paper: Coated One-Side, C1S (James River Corp.), Gravure Printed.



1Joncryl 89. Other choices include Lucidene 370 and Vancryl 989.2Joncryl 61. Other choices include Morcryl 134 and Vancryl 68S.3Photos taken at 3.7x magnification.

No IPA 2% IPA 1% 1% 1% 1%No Surfactant Surfynol SE-F Surfynol 420 Surfynol 440 Surfynol 104

Printability Rating(1 = Poor; 10 = Excellent)

Coated Stock (shown above) 4 7 8 9 8 9

Flexible Paper 6 7 9 9 8 9


Dyne

s/cm

25

35

45

EquilibriumDynamic

Surface Tension68.7

38.3

44.7

30.5

35.5

29.534.1

31.7

35.9

28.232.6

38.8

Ink

Dens

ity (g

/ml)

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.760.81 0.81 0.84

0.73

0.84

No IPANo Surfactant

2% IPAControl

1%Surfynol SE-F

1%Surfynol 420

1%Surfynol 440

1%Surfynol 104

Unagitated Ink

- - - -

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© Air Products and Chemicals, Inc., 1999 (20000) Printed in USA 120-9937

The information in this literature is offeredwithout charge for use by technically qualifiedpersonnel at their discretion and risk. All state-ments, technical information and recommenda-tions are based on tests and data which webelieve to be reliable, but their accuracy orcompleteness is not guaranteed and no war-ranty of any kind is made.

Appendix

Experimental Procedures

Sample Preparation

Ink bases for each formulation listed in Figures1–4 were prepared both with and withoutalcohol or surfactant. For each flexible film ink,90 parts of the base were mixed with 10 partsof a combination of surfactant, alcohol andwater. For the paper substrate inks, 98 partsof the ink base were combined with 2 partsalcohol or surfactant and water. All formula-tions were adjusted to a viscosity of 25 sec-onds on a #2 Zahn cup.

Surface Tension Measurements

Surface tension values were determined on aSensaDyneTM 6000 Tensiometer (Chem-DyneResearch Corporation). Samples were diluted50/50 with water to reduce viscosity to withinthe operating range of the instrument; there-fore, the values are relative. Both equilibrium(1 bubble/second) and dynamic (5 bubbles/second) surface tensions were evaluated. Thecritical surface tensions of the substrates weredetermined via surface tension fluids fromDiversified Enterprises, Inc.

Printability

Flexographic printing (flexible films and coatedstock) was performed using a Pamarco handproofer equipped with a #165 anilox. A Geigerpress was utilized for gravure printing (flexiblepaper). Printability was visually evaluated on aqualitative scale of 1–10, with 10 being anexcellent film. Dewetting and pinholing werethe major defects on the nonporous sub-strates, and mottling was the major defect onthe porous substrates.

Foam Test

Ink samples (50 grams) were agitated at12,000 rpm for 1 minute utilizing a WaringBlender. Densities were measured before andafter agitation.

Blocking

Blocking was evaluated via ASTM D2793-69.

Adhesion

Adhesion was evaluated via the 610 Scotchtape test.

Water Resistance

Water droplets were placed on the cured filmsand wiped off at the following intervals: 0.5, 1,2 and 5 minutes.

Gloss

Gloss values were determined at 60 degreeswith a Dr. Lange Reflectometer.

Plate Swell

One-inch squares of Letterflex Photopolymerflexographic printing plate on a steel backing(WR Grace) were cut and then pre-weighed onan analytical balance. The plates were placedin the formulated inks for 24 hours, then re-moved, cleaned and re-weighed to determineplate swelling via weight increase. Thesevalues were then compared with those of thecontrol containing no surfactant.

Raw Material Suppliers

Air Products and Chemicals, Inc.:Vancryl 954, Vancryl 68S;

Sun Chemical Corporation:Flexiverse Phthalo Blue GS Dispersion,Flexiverse Diarylide AAOT Yellow Dispersion;

S.C. Johnson Polymer:Joncryl 624, Joncryl 89, Joncryl 61,Jonwax 26 PE Wax Emulsion.

For More Information

If you’d like additional information, write or callAir Products and Chemicals, Inc., at the follow-ing locations.

Air Products and Chemicals, Inc.Performance Chemicals7201 Hamilton BoulevardAllentown, PA 18195-1501Telephone: 800-345-3148(Outside U.S./Canada 610-481-6799)Fax: 610-481-4381http://www.airproducts.com

Latin AmericaAir Products and Chemicals, Inc.Latin American Region7201 Hamilton BoulevardAllentown, PA 18195-1501Telephone: 610-481-7290Fax: 610-481-5817

Air Products and Chemicalsde Mexico S.A. de C.V.Suite 26, Piso 12World Trade CenterAvenida de las Naciones No 1Col. Napoles, México D.F. 03810MexicoTelephone: +52-5-488-0790Fax: +52-5-488-0798

Air Products Gases Industriais Ltda. (APGIL)Praca Radialista Manoel de Nobrega, 65Casa Verde02517-160 São Paulo, SPBrazilTelephone: +55-11-856-1707Fax: +55-11-856-1781

EuropeAir Products Nederland B.V.Kanaalweg 15, Box 31933502 GD UtrechtNetherlandsTelephone: +31-30-2857100Fax: +31-30-2857111

AsiaAir Products Japan, Inc.3-18-19, Toranomon, Minato-KuTokyo 105JapanTelephone: +81-3-3432-7031Fax: +81-3-3432-7052

Air Products Asia, Inc.Rm 5507-10 Hopewell Centre183 Queen’s Road EastWanchaiHong KongTelephone: +852-2527-0515Fax: +852-2527-1957

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Graphics Arts Surfynol Surfactants Superior Substrate Wetting Agents

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