Wingtack Hydrocarbon Resins in Pressure Sensitive Adhesives
Transcription
Wingtack Hydrocarbon Resins in Pressure Sensitive Adhesives
HYDROCARBON SPECIALTY CHEMICALS tel : (33) (0) 3 44 55 68 05 fax : (33) (0) 3 44 55 67 06 http://www.crayvalley.com Wingtack Hydrocarbon Resins in Pressure Sensitive Adhesives Application Guide L105-1 _ January 2010 PSA GENERALITIES Definition of a PSA Chemistries Formulating Styrene Block Copolymers Coating process Testing PSA Wingtack tackifying resin range Applications & orientation formulations Labels Tapes Films L105-1 _ January 2010 2 Definition A PSA (Pressure Sensitive Adhesive) is an adhesive that remains permanently sticky and can adhere with only a light pressure (finger pressure). Synonymous: Self-adhesive Permanently tacky L105-1 _ January 2010 3 Chemistries A PSA can be based on different chemistries and in various solvents: Water based Solvent based Hot Melts (WB) (SB) (HM) X X X (UV) X X X X Acrylic copolymers Styrene block copolymers (SBC) Rubber-based (natural or synthetic) L105-1 _ January 2010 X 4 Chemistries Acrylic based PSA (WB or SB) The acrylic itself gives the properties: no need to formulate Optional formulation: tackifying resin, antifoam, wetting agent… Styrene block copolymers & rubber-based PSA (WB, HM or SB) Must be formulated with tackifier: SBC, NR and SBR are not tacky (PSA) by themselves. Formulation comprises at least: a polymer (SBC, NR or SBR) a tackifying resin a plasticizer L105-1 _ January 2010 5 Formulating SBC based PSA Styrene Block Copolymers Incompatible blocks of hard (poly-styrene, Tg=95°C) and soft (polyisoprene, Tg=- 60°C or poly-butadiene, Tg=- 90°C) pol ymers → SIS or SBS Different architectures Soft phase PS Diblock Star / Radial Hard phase PS PI or PB PS PS PS PS Triblock PS Global structure of SBC L105-1 _ January 2010 6 Formulating SBC based PSA Dynamical Mechanical Analysis of a SIS block copolymer showing the 2 incompatible phases: • The soft / elastomer phase made of poly-isoprene (Tg# - 60°C) giving TACK • The hard phase made of poly-styrene (Tg# 95°C) givi ng COHESION G' Tanδ Tg (PI) L105-1 _ January 2010 Tg (PS) 7 Temperature (°C) Formulating SBC based PSA Formulation contains at least: Styrene Block Copolymer to choose depending on the final application Tackifying resin to choose compatible with the soft phase of the SBC in order to decrease G' modulus to meet Dahlquist's criteria Plasticizer in general: paraffinic or naphthenic oil Log G‘ et Log G’’ POLYMER POLYMER + RESIN 10 10 10 9 99 8 88 7 77 6 66 5 55 4 44 3 33 Temperature Temperature L105-1 _ January 2010 non PSA Critè re de Dahlquist Dahlquist criteria 8 PSA Formulating SBC based PSA Two different types of resins can be added: WINGTACK aliphatic tackifying resin: Low Molecular weight G’ and soft phase viscosity Compatible with the soft phase Dahlquist criterium ok G’ < 105 Soft phase Tg High Tg (40 – 50 °C) WINGTACK = Tackifying resin NORSOLENE S 155 aromatic reinforcing resin: Low Molecular weight Viscosity (PS) Tg (PS) remains high Compatible with the PS phase High Tg (95 - 100 °C) High SP NORSOLENE = Reinforcing resin L105-1 _ January 2010 9 Formulating SBC based PSA Tackifying resin : effect on Modulus (G’) and Tg G’ (Pa) Neat Polymer + Tackifying resin + plasticizer PSA Window 1.E+05 - 10 L105-1 _ January 2010 10 + 10 Tg (°C) Formulating SBC based PSA High SP C9 resin : effect on performances Material Quantity SIS Tack = affe cte d by Norsolène S 155 % 30 44.5 25 50 to 25 NORSOLENE S 155 20 N / 25 mm WINGTACK C5 0 to 25 Plasticizer 15 10 5 5 0 Antioxidant 0 0.5 10 20 30 40 50 60 % Norsolène S 155 (WINGTACK + NORSOLENE S 155 = 100) Re sistance at 70 °C=de pe nding on Norsolène S 155 % 40 180 35 160 30 140 Time ( hours) N / 25 mm Peel strength = depending on Norsolène S 155 % 25 20 15 120 100 80 60 10 40 5 20 0 0 0 10 20 30 40 50 0 60 L105-1 _ January 2010 10 20 30 % Norsolène S 155 % Norsolène S 155 11 40 50 60 Formulating SBC based PSA MATERIAL EFFECTS TYPE SBC Thermoplastic behaviour provides flow and bond SBS, SIS, SEBS Cohesion/strength Tackifying resin ( compatible with Midblock) Reinforcing resin (compatible with endblock) Increase Tg of Midblock Wingtack C5 and C5/C9 Decrease viscosity Wingtack 10 (liquid C5 polymer: no bleeding) Increase cohesion and Norsolene S155 T° resistance Fillers Reduce cost Calcium carbonate Pigment Plasticizer Reduce viscosity, cohesion, modulus and hardness Increase tack at low temperature Antioxidant L105-1 _ January 2010 Reduce degradation of PSA during manufacturing and use 12 Oil (naphthenic, paraffinic) Formulating SBC PSA Styrene content: Increases the cohesion Decreases tack at room temperature PS block MW: Increases tensile strength Increases temperature resistance Increases Hot-melt viscosity Diblock content: Increases tack and adhesion Decreases hardness Decreases cohesion Increases label convertibility SBS is more cohesive and less tacky than SIS. SBS need to be tackified with C9/C5 resins which will plasticize as well the PS end blocks with the following consequences : Increase of tack/adhesion Possible decrease of cohesion L105-1 _ January 2010 13 Formulating SBC PSA Effect on performances with the increase of different parameters: Parameters Polymer Tack Adhesion Cohesion Quantity Styrene Mw (PS) Diblock Tackifying resin Quantity % aromatic Mw Tg Reinforcing resin Quantity (few) Mw Tg L105-1 _ January 2010 14 (few) SAFT Coating process Drying / Cooling Roll of finished material Liner Laminating Release or anchorage treatment (silicone / Corona, Flame) L105-1 _ January 2010 PSA coating 15 Facestock (for labels) or protection (for tapes) Coating process Raw materials Formulation Coating Coating on different substrates Printing Cutting a Cr Polyolefin (PE, PP…) Silicone (for paper and PVC substrates) PET y lle a yV Release liner Different coating systems Mayer bar Gravure roller Knife Slot die Curtain coating … Adhesive Facestock Lab coating machine L105-1 _ January 2010 16 Testing DMTA: Dynamical Mechanical Thermal Analysis Shear Loop tack Probe tack 10 MW and polydispersity y 10 2.5 Tack = adhesion 10 9 G" (Pa) Peel Entranglement s = Cohesion 10 8 2.0 Flow 10 7 1.5 tan_delta G' (Pa) 10 6 1.0 10 5 10 4 0.5 Green: G’’= viscous modulus 10 3 Red: Tan δ =G’’/G’ 2 10 -60.0 -42.0 -24.0 -6.0 12.0 30.0 48.0 66.0 Temp [°C] L105-1 _ January 2010 Blue: G’ = elastic modulus 17 84.0 102.0 0.0 120.0 Testing Adhesion: strength of the interface between the adhesive and the substrate, measured by peel test with an angle of 90° or 180°. Adhesive failure Substrates 180° peel Tack: initial adhesion, measured by loop tack or rolling ball tack Rolling ball tack Loop tack L105-1 _ January 2010 18 Testing Cohesion: intrinsic strength of the adhesive, measured by shear test Adhesive Substrates Cohesive failure Static shear SAFT: Shear Adhesion Failure Temperature (cohesion measured under an increase of temperature) L105-1 _ January 2010 19 Optimisation Design of experiments are often used to optimise formulations in order to reach the best compromise, depending on the final application. A: Wingtack ET 2 60.0 113 2 0.0 0.0 116 110 120 123 2 2 15.0 B: Norsolene S155 L105-1 _ January 2010 45.0 15.0 C: Oil SAFT°C 20 Wingtack range C9 modified C5 Pure C5 5 0 WT 10 (10°C) WT Plus (96°C) 8 15 WT Extra (97°C) WT ET (95°C) 25 WT STS (94°C) 30 Aromatic content % WT 86 (87°C) WT 95 (98°C) WT RWT 7850 (102°C) WT 98 (98°C) Isoprene compatible Butadiene compatible Pure C5 (pure aliphatic hydrocarbon) resins are compatible with isoprene C9 modified C5 (aromatic modified C5) resins are compatible with isoprene, butadiene and styrene (plastification of styrene end-blocks) ⇒ the best compatibility gives the best tack and adhesion L105-1 _ January 2010 21 Wingtack range Typical values WT 10 WT 95 WT RWT 7850 WT 98 WT PLUS WT EXTRA WT ET WT STS WT 86 R&B SP, °C 10 98 102 98 96 97 95 94 87 Tg , °C -31 55 52 48 53 52 50 44 42 1.5 1.7 2.4 3.1 1.6 1.4 2.0 3.0 1.2 Mn 370 1100 1000 1000 1000 1100 1000 850 650 Mw 500 1700 2100 2000 1600 2000 1600 1500 1300 Mw/Mn 1.4 1.5 2.1 2.0 1.6 1.8 1.6 1.8 2.0 COLOUR, G (50% Toluene solution) GPC g/mol L105-1 _ January 2010 22 Application vs adhesive performances Classification of PSA Permanent (paper labels, packaging tapes, brown envelopes…) High initial tack High adhesion Cohesion depending on application Repositionable (book covers, white envelopes…) High final adhesion but low build-up in performance (can be removed and replaced immediately after sticking, not possible after a couple of days) Medium to low tack Cohesion depending on application Removable (temporary protections, masking tapes…) Must not damage the substrate or leave any residue when removed High cohesion Medium tack Adhesion depending on application L105-1 _ January 2010 23 Application vs market: Labels a Cr Label construction y lle a yV Release liner Adhesive Examples Face stock Face stock treatment Protective liner Paper None Silicone Plastic (PE, PP) Corona, Flame Non treated plastic PVC None Silicone L105-1 _ January 2010 24 Facestock Application vs market: Labels Formulations SBC with high di-block content is compulsory to have good die-cutting (low elastic modulus and high Tan δ at low frequency) High tackifying content High oil content, naphthenic oils are preferred because they will bring higher tack Key performance characteristics Good die-cutting and convertibility (low elastic modulus) High tack on low energy substrates (achieved with a high level of tackifier) L105-1 _ January 2010 25 Application vs market: Labels Orientation formulations Permanent label Material Low temperature label Quantity Material Quantity SIS (16%S, 55% DB) 15 SIS (16%S, 55% DB) 15 SBS (33%S, 78% DB) 20 SBS (33%S, 78% DB) 20 Wingtack ET 30 Wingtack ET 45 Wingtack 86 25 Wingtack 10 10 - 20 Naphthenic oil 10 Naphthenic oil 0 - 10 Antioxidant 1 Antioxidant L105-1 _ January 2010 26 1 Application vs market: Tapes Single coated Tape construction Easy release coating (LAB) Backing Primer Examples Backing Adhesive Anchorage treatment Release Non polar plastic (PE, PP) Corona, Flame None Polar plastic (PET) Corona, Flame LAB* Paper Primer Silicone Reinforced tape Release coating Backing Bundles of reinforcing filaments Adhesive Double coated Textile None LAB PVC Primer None Release liner Adhesive Carrier Adhesive *LAB= Easy release coating L105-1 _ January 2010 27 Application vs market: Tapes Formulation Highly cohesive polymer (high styrene, low di-block content…) Medium quantity of tackifying resin Just the oil quantity needed for processing (to decrease migration) Wingtack 95 can be used to have low noisy tapes (in SIS based formulations) Norsolene S155 can be added up to 10% to reinforce cohesion and temperature resistance Key performance characteristics High cohesion is generally required Good wetting Other properties depend on final application L105-1 _ January 2010 28 Application vs market: Tapes Orientation formulations OPP tape Kraft tape Material Material Quantity Quantity SIS (15%S, 19% DB) 40 SIS (15%S, 38% DB) Wingtack 98 48 Wingtack 98 45 - 50 Naphthenic oil 11 Oil 5 - 10 Antioxidant 1 Antioxidant L105-1 _ January 2010 29 45 1 Application vs market: Tapes Orientation formulation for OPP tapes using SIBS polymer Material PSA Tape PSA Tape Kraton D1171™ (SIBS 18%S, 26%DB) 20 20 Kraton D1118™ (SBS 33%S, 78%DB) 20 - - 20 49.8 49.8 Nyflex 222™ 10 10 Antioxidant 0.2 0.2 Rolling ball tack (cm) 1.4 1.7 Loop tack (N/25mm, ss) 36.7 27.3 180° Peel (N/25mm, ss) 24 15.1 SAFT (°C, 1/2kg) 84 83 Kraton D1102™ (SBS 29.5%S, 17%DB) Wingtack STS L105-1 _ January 2010 30 Application vs market: Tapes Orientation formulations Masking tape Material Quantity SIS (15%S, 19% DB) 35 Wingtack Plus 44 Norsolene S155 9 Calcium carbonate 5 Titanium dioxide 1 Naphthenic oil 5 Antioxidant 1 L105-1 _ January 2010 Key performance characteristics : Very good cohesion No transfer after ageing 31 Application vs market: Films Film construction Examples Face stock Face stock treatment Protective liner PE, PP Corona, Flame None PVC None Silicone L105-1 _ January 2010 32 Application vs market: Films Orientation formulations SB protective film HM protective film Material Material Quantity Quantity SIS (15%S, 19% DB) 45 Natural rubber 50 Wingtack 98 50 Wingtack 95 45 Paraffinic oil 5 Paraffinic oil 5 Antioxidant 1 Antioxidant 1 Solvent L105-1 _ January 2010 33 To get the right viscosity WINGTACK in PRESSURE SENSITIVE ADHESIVE These results obtained in our laboratory are given in good faith according to the method used and the samples checked. The values cannot be used to set specifications. They are indicated without Cray Valley’s guarantee or liability. All given formulations are starting formulations and they are indicated without Cray Valley’s guarantee or liability. They are based on our present technical knowledge and experience. They do not relieve processors of the responsibility of carrying out their own tests and experiments, because many factors that could influence the result may arise during processing and application; neither do they imply or give legally binding assurance of certain properties or of suitability for a specific purpose. Any proprietary formulation should be respected. Shelf life : Norsolene and Wingtack resins are inert and stable. Their shelf life mainly depends on the storage conditions and end use. Their average shelf life is about 2 years. This average shelf life is given without Cray Valley’s guarantee because Cray Valley does not control end uses and the storage conditions at customers. Storage : all resins with a low softening point present a risk of solidifying, which increases in hot weather. Therefore for softening points of less or equal to 100 °C, we recommend : storage in a cool (25 °C max), ventilat ed area, out of the sunlight; do not stack pallets; avoid storage for prolonged period. L105-1 _ January 2010 34