AdhesivesAdhesives

Pressure Sensitive Adhesive Tapes for Sales and Marketing Professionals

Tape University Basics May 12, 2009

Larry K. PostNorth American Technical Services &

Strategic Account Technology ManagerAshland, Inc.

Dublin, OH

Larry K. PostNorth American Technical Services &

Strategic Account Technology ManagerAshland, Inc.Dublin, OH

• More than 30 years in PSA tape industry

• Specializing in solution, emulsion and radiation cure PSA adhesives

• B.S. and M.S. in chemistry from Wright State University

• Graduate research on synthesis and polymer characterization of new polymerizable herbicide monomers

Types of AdhesivesTypes of Adhesives

• Calendered (Rubber)• Hot Melt (Thermoplastic

Elastomers)• Reactive (Acrylic and

Silicone)• Radiation Cured

• Calendered (Rubber)• Hot Melt (Thermoplastic

Elastomers)• Reactive (Acrylic and

Silicone)• Radiation Cured

• Water Based (Rubber and Acrylics)

• Solvent (Acrylic, Rubber, and Silicone)

• Water Based (Rubber and Acrylics)

• Solvent (Acrylic, Rubber, and Silicone)

Solid AdhesivesSolid Adhesives Liquid AdhesivesLiquid Adhesives

Common PSAsCommon PSAs

• Natural Rubber

• Synthetic Rubber

• Acrylic Adhesives

• Silicone Adhesives

Rubber Based AdhesivesRubber Based Adhesives• Elastomer

• Natural and Synthetic Rubbers (Butyl, Styrene Butadiene, Polyisoprene, Thermoplastic Elastomers)

• Tackifiers• Natural (Rosin, Rosin Salts and Esters) • Synthetic Hydrocarbons(C5, C9, Polyterpenes)

• Fillers• Clay, Calcium Carbonate, Talc and Silica

• Plasticizing Oil• Polybutene • Naphthenic Oils

• Anti-oxidants• Cross Linking Agents• Flame Retardants• Colorants• Deodorants

• Elastomer• Natural and Synthetic Rubbers (Butyl, Styrene Butadiene,

Polyisoprene, Thermoplastic Elastomers)• Tackifiers

• Natural (Rosin, Rosin Salts and Esters) • Synthetic Hydrocarbons(C5, C9, Polyterpenes)

• Fillers• Clay, Calcium Carbonate, Talc and Silica

• Plasticizing Oil• Polybutene • Naphthenic Oils

• Anti-oxidants• Cross Linking Agents• Flame Retardants• Colorants• Deodorants

Performance Characteristics and Features

Performance Characteristics and Features

• Multi-component systems requires intensive processing

• Natural and synthetic components• Applied as 100% solids and from solutions• Cost effective• Good tack and adhesion to a variety of surfaces

including low surface energy surfaces• Good shear strength

• Multi-component systems requires intensive processing

• Natural and synthetic components• Applied as 100% solids and from solutions• Cost effective• Good tack and adhesion to a variety of surfaces

including low surface energy surfaces• Good shear strength

Duct, and some Packaging and Masking Tapes are based on Natural Rubber

Performance CharacteristicShortcomings

Performance CharacteristicShortcomings

Fair Chemical, UV and Oxidation Resistance Poor Elevated Temperature Resistance Moderate Useful Life Time Requires Extensive Processing

(except hot melt)

Fair Chemical, UV and Oxidation Resistance Poor Elevated Temperature Resistance Moderate Useful Life Time Requires Extensive Processing

(except hot melt)

Rubber vs. Thermoplastic Rubber Adhesives

Rubber vs. Thermoplastic Rubber Adhesives

• Tackifiers• Anti-oxidants• Fillers• Oils• Same formulating

principles• Can be coated as

100% solids or from solution

• Tackifiers• Anti-oxidants• Fillers• Oils• Same formulating

principles• Can be coated as

100% solids or from solution

• Natural rubber adhesives have higher operating temperatures

• Natural rubber can be chemically crosslinked vs. physical crosslinks for thermoplastic rubber

• Thermoplastic rubber adhesives melt

• Natural rubber adhesives require intensive mixing

Similarities Differences

Natural Rubber

Tackification

Natural Rubber

Tackification

From Handbook of PSA Technology 3rd Edition, pg. 265, edited by Don Satas,

Satas & Associates, Rhode Island © 1999.

From Handbook of PSA Technology 3rd Edition, pg. 265, edited by Don Satas,

Satas & Associates, Rhode Island © 1999.

Fig. 13-3 Effect of resin concentration on peel adhesion (X), tack (*) and shear resistance (0) for hydrocarbon resin in natural rubberFig. 13-3 Effect of resin concentration on peel adhesion (X), tack (*) and shear resistance (0) for hydrocarbon resin in natural rubber

1400

1200

1000

800

600

400

200

Synthetic AdhesivesSynthetic Adhesives

• Acrylic Adhesives• 2-Ethyl Hexyl Acrylate, Butyl Acrylate

and co-monomers• Cross Linker

• Silicone Adhesives• Dimethyl and Diphenyl Dimethyl

Silicones• Catalyst (Platinum or Peroxide)

• Acrylic Adhesives• 2-Ethyl Hexyl Acrylate, Butyl Acrylate

and co-monomers• Cross Linker

• Silicone Adhesives• Dimethyl and Diphenyl Dimethyl

Silicones• Catalyst (Platinum or Peroxide)

• Colorless-excellent clarity• Balanced shear, adhesion

and tack• Low Tg

• Excellent resistance to thermal and UV degradation

• Excellent aging characteristics

• Broad temperature performance range

• Colorless-excellent clarity• Balanced shear, adhesion

and tack• Low Tg

• Excellent resistance to thermal and UV degradation

• Excellent aging characteristics

• Broad temperature performance range

• Good resistance to non-polar solvents

• Water resistant• Non-corrosive• Easily formulated• Biocompatible (ISO

10993)• Sterilizable (EtO &

Radiation) chemistry

Acrylic PSA FeaturesAcrylic PSA Features

Solution AcrylicsSolution Acrylics

• Good balance of properties; generally higher performance than emulsion acrylics

• Coater ready

• Mechanically stable

• Viscosity controlled by solvent & solids

• Newtonian rheology

• Solvent management

• Good balance of properties; generally higher performance than emulsion acrylics

• Coater ready

• Mechanically stable

• Viscosity controlled by solvent & solids

• Newtonian rheology

• Solvent management

UL foil tape, mounting tapes, and transfer tapes

Emulsion AcrylicsEmulsion Acrylics

• Polymerized in water (surfactant needed)

• Good properties similar to solution acrylics but typically lower adhesion, tack and shear.

• Stabilize emulsion from biological attack

• Some sensitive to water

• Environmentally safe

• Less expensive than solution acrylics

• Polymerized in water (surfactant needed)

• Good properties similar to solution acrylics but typically lower adhesion, tack and shear.

• Stabilize emulsion from biological attack

• Some sensitive to water

• Environmentally safe

• Less expensive than solution acrylics

Packaging tape largest application for emulsion acrylics

From Advances in Pressure Sensitive

Adhesive Technology, Don Satas, p. 3, ©

1989, Satas & Associates, RI.

Effect of Crosslinking and Molecular Weight on Mechanical Properties

Effect of Crosslinking and Molecular Weight on Mechanical Properties

Silicone Adhesives’ FeaturesSilicone Adhesives’ Features

• Wide temperature use range up to 500F • Biocompatible (ISO 10993)• Sterilizable (EtO and Radiation)• Resistant to moisture, UV, oxidation, chemical

and biological attack• Excellent electrical insulation properties• Adheres to difficult to bond to substrate such as

polyimides and fluoropolymers• Clean removability

• Wide temperature use range up to 500F • Biocompatible (ISO 10993)• Sterilizable (EtO and Radiation)• Resistant to moisture, UV, oxidation, chemical

and biological attack• Excellent electrical insulation properties• Adheres to difficult to bond to substrate such as

polyimides and fluoropolymers• Clean removability

Silicone Adhesives have….Silicone Adhesives have….

• Better resistance to moisture, microbes, UV, chemicals, and oxidation

• Broader temperature use range

• Lower adhesion and tack at room temperature, but better properties at temperature extremes

• More expensive

• Better resistance to moisture, microbes, UV, chemicals, and oxidation

• Broader temperature use range

• Lower adhesion and tack at room temperature, but better properties at temperature extremes

• More expensive

…than acrylic and rubber based adhesives

Applications for Silicone PSAsApplications for Silicone PSAs

• Printed Circuit Board Mask• Solder Mask• Electrical Insulating Tapes• Silicone to Silicone Bonding Applications

(Splicing Tape)• Low Friction Tape• Plasma Spray Tape• Medical Applications

• Printed Circuit Board Mask• Solder Mask• Electrical Insulating Tapes• Silicone to Silicone Bonding Applications

(Splicing Tape)• Low Friction Tape• Plasma Spray Tape• Medical Applications

Silicone PSA Compositions MQ Silicate Tackifier Resin

From T. Mitchell Dow Corning Presentation, February 2002

Properties of AdhesivesProperties of Adhesives

• Chemistry• Molecular Weight • Rubber:Resin:Filler:Oil

Ratio• Degree of Cross linking• Tg

• Chemistry• Molecular Weight • Rubber:Resin:Filler:Oil

Ratio• Degree of Cross linking• Tg

• Chemistry• Molecular Weight• Degree of Chain

Entanglement• Degree of Cross Linking• Tg

• Chemistry• Molecular Weight• Degree of Chain

Entanglement• Degree of Cross Linking• Tg

Rubber Adhesives Acrylic & Silicone Adhesives

Physical properties and fitness for use are governed chemistry, molecular weight, crosslink density, and additives

Considerations for Adhesive SelectionConsiderations for Adhesive Selection• Environment

• Temperature of Application and Use• Relative Humidity• Exposure to Sunlight, Water, Chemicals

• Application• Machine or Hand Applied• Speed of unwind or liner removal• Pressure of application• Time for bond formation

• Functionality• Surface (Chemistry, Texture and Cleanliness)• Barrier Properties• Removable residue free, repositionable or permanent• Leachable Materials• FDA compliant (skin and food)• Regulatory compliant• Material and Performance specifications• Life Time

• Cost

• Environment• Temperature of Application and Use• Relative Humidity• Exposure to Sunlight, Water, Chemicals

• Application• Machine or Hand Applied• Speed of unwind or liner removal• Pressure of application• Time for bond formation

• Functionality• Surface (Chemistry, Texture and Cleanliness)• Barrier Properties• Removable residue free, repositionable or permanent• Leachable Materials• FDA compliant (skin and food)• Regulatory compliant• Material and Performance specifications• Life Time

• CostChemistry and Process

determine adhesive properties which combined drive COST!

Performance ComparisonPerformance Comparison

• TACK and PEEL: Rubber>Acrylic>Silicone

• COHESIVE STRENGTH at ELEVATED TEMPERATURE: Silicone>Acrylic>Rubber

• STABILITY: Silicone>Acrylic>Rubber

• TEMPERATURE RANGE: Silicone>Acrylic>Rubber

• COST: Silicone>Acrylic>Rubber

• Convertibility Silicone>Acrylic>Rubber

• TACK and PEEL: Rubber>Acrylic>Silicone

• COHESIVE STRENGTH at ELEVATED TEMPERATURE: Silicone>Acrylic>Rubber

• STABILITY: Silicone>Acrylic>Rubber

• TEMPERATURE RANGE: Silicone>Acrylic>Rubber

• COST: Silicone>Acrylic>Rubber

• Convertibility Silicone>Acrylic>Rubber

How Things “Stack-Up”How Things “Stack-Up”

CHARACTERISTIC RUBBER ACRYLIC MOD ACRYLIC SILICONE Cost Lowest Medium/High Medium/High Very High

Tack Medium/High Medium/Low High Low

Temperature Resistance Low High Low/Moderate Very High

Adhesion Medium/High Moderate/High High Medium/Low

Shear Medium/High Moderate/High Low Excellent

Solvent Resistance Poor Good Low/Moderate Excellent

UV Resistance Poor Excellent Poor Excellent

Plasticizer Resistance Poor Moderate/Good Poor/Moderate Excellent

Low-surface-energy Materials Excellent Poor/Moderate Excellent Poor*

High-surface-energy Materials Excellent Excellent Excellent Moderate

J Johnston - Personal communication

* High to low surface energy silicones, poor to low surface energy ethylenes

How do you know which adhesive to use?

How do you know which adhesive to use?

Factors to Consider•Surfaces

•Application•Functional Properties•Service Temperature•Thermal Resistance•Chemical Resistance

•Barrier Properties•Durability

•Construction•Cost

The selection of the type of adhesive is determined by understanding the functional properties required, application technique and cost.