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Psa's and tapes the mfgr process
- 1. The Manufacturing Process PSA’s andTapes 28-01-2013 1
- 2. Introduction PSA Tapes werefirst introduced about 150 years ago. Initially medical tape and dressing was developed and a U.S. Patent was issued in 1846. PSA’s are widely used since the 19 th century. Industrial Tapes were introduced between the 1920 ,s and 1930,s . Hot Melt adhesives were introduced in the 1940,s . PSA Tapes are used for many different Applications. 28-01-2013 2
- 3. What is pressuresensitive adhesive ? Pressure sensitive adhesive, is adhesive which forms a bond when pressure is applied to bond it with the adherent. This is a material that holds two surfaces together solely by surface contact, which is achieved by slight initial external pressure. These adhesives require no activation with water, solvent or heat, and firmly adhere to many dissimilar surfaces with minimal pressure. Aggressive and permanently tacky at room temperature, PSAs can be used for bonding materials such as plastic, paper, metal, glass, and wood. As the name "pressure sensitive" suggests, the bond is influenced by the amount of pressure that is applied on the adhesive to the surface. 28-01-2013 3
- 4. Pressure sensitive adhesivesare designed with a balance between flow and resistance to flow. The bond forms because the adhesive is soft enough to flow, or wet, the adherent. The bond has strength because the adhesive is hard enough to resist flow when stress is applied to the bond. PSAs exhibit viscoelastic (viscous and elastic) properties, both of which are used for proper bonding. Pressure sensitive adhesives are characterized by their shear holding. The ability to hold in a shear mode is related to the formulation, coating thickness, rub-down, temperature, etc. 28-01-2013 4
- 5. Factors affecting ? Surfacefactors , such as smoothness, surface energy, removal of contaminants, etc. also , play important role in proper bonding. PSAs are usually designed to form a bond and hold properly at room temperatures. PSAs typically reduce or lose their tack at low temperatures and reduce their shear holding ability at high temperatures; special adhesives are made to function at high or low temperatures. It is important to choose an adhesive formulation which is designed for its intended use conditions. Once the adhesive and the adherent are in contact, there are molecular interactions such as , van der Walls forces , involved in the bond, which contribute significantly to the ultimate bond strength. 28-01-2013 5
- 6. Common Adhesive Types andTheir Properties 28-01-2013 6
- 7. Convenient & fastmeans of application. Ease of removability without damage of the substrate. Wide choice. Suitable for a number of applications. Easy printability. Easy laminate / bond ability Easy cut ability , die- cut ability. Structural integrity. Dimensional stability. Shape retention. PSA Tapes Key features 28-01-2013 7
- 8. Unique Characteristics Provide temporary andpermanent holding application. Provide insulation , thermal as well as electrical. Provide sound and vibration proofing. Cheaper packaging solution. Mounting. Assembling. Sealing Splicing. Medical / surgical mounting. 28-01-2013 8
- 9. For many years,rubber/resin formulations have been available that combine natural or synthetic rubber with tackifying resins, oils, antioxidants, or other ingredients as needed. They are typically either solvent-based or used in hot melts, and the aggressive nature of rubber adhesives makes excellent bonding easy to achieve. These adhesives are known for their high level of adhesion to a variety of substrates and facestocks, as well as their high coatability. Rubber-based adhesives provide high tack and peel, and make excellent general-purpose adhesives, because of their ability to adhere well to several non-polar, low- energy surfaces, including polyethylene and polypropylene. In general, rubber- based adhesives are often a more economical choice compared to most acrylics. Disadvantages of rubber-based adhesives include limited effectiveness when exposed to certain chemicals, UV rays, or high temperatures (over 150°F/66°C). In addition, they are more susceptible to oxidation and may darken, lose their tack, and become brittle if overexposed. Also, rubber/resin adhesives may turn soft and gummy if plasticizers, used in most polyvinyl chloride films (PVC), migrate into the adhesive. Rubber Base 28-01-2013 9
- 10. The other typeof adhesive chemistry commonly used in PSAs is acrylic. Acrylic adhesives can either be solvent- or water-based, and are formulated by reacting monomers with the desired properties, which are then typically crosslinked to form the type of polymer needed. Monomers are the building blocks of polymers and are considered to be either “soft” or “hard.” The combination of hard and soft monomers can be adjusted based on the level of adhesive (polymer) performance needed. Crosslinking polymers improves the cohesive strength (internal strength of the adhesive, or the ability to stick to itself) of the acrylic formulation and can be accomplished in one of three ways: the use of thermal heat energy; by self- curing when a solvent is removed during the drying process; or through UV or EB non-thermal radiation. In general, acrylics are relatively firm and durable, but are not as aggressive as rubber-based adhesives. An acrylic adhesive can be modified to alter its adhesion properties based on the selection of monomers used, the level of polymerization created, or by adding tackifying resins or other chemicals. Acrylic base 28-01-2013 10
- 11. The advantages ofacrylic adhesives are typically the opposite of rubber adhesives. Acrylics provide excellent temperature, UV and oxidation resistance; therefore, they are often the preferred choice for outdoor applications. They resist the negative plasticizing action that can occur with rubber and hold up well to chemical exposure. Acrylic-based adhesives are very durable and have clarity and color stability. Acrylics bond well to polar surfaces like metal, glass, polyesters and polycarbonates, and have high peel, tack, and shear. Disadvantages of acrylics usually include poor adhesion to low-energy surfaces, such as polyethylene and polypropylene, as well as lower overall adhesion compared to rubber unless the adhesive is highly engineered. In general, acrylics are often more expensive than rubber-based adhesives. Acrylic base 28-01-2013 11
- 12. Silicone adhesives areanother chemical option for PSAs but are less common than rubber or acrylic. These specialized adhesives consist of silicone polymers that provide adhesion to silicon and other hard-to-adhere-to materials. Silicone-based adhesives can maintain adhesion over a range of temperatures; however, beyond their ability to adhere to difficult surfaces, their overall adhesive strength is low. Silicone adhesives are also more expensive. Silicone base 28-01-2013 12
- 13. Characteristics of pressure sensitiveadhesive ? Adhesion : Tack, Peel Resistance, Cohesive strength / or Shear resistance. Converting Properties : Printability, ability to Laminate, Cut ability, Die-cut ability. End Use Application : Ageing Resistance, Chemical and water resistance, bonding and de bonding properties, Process ability. 28-01-2013 13
- 14. Adhesion : Tack, isthe Wet ability of adhesive is nothing but to form a bond in a short time , with little pressure . hence the adhesive needs to have good flow. Tack depends upon 1. Viscosity The ability of the adhesive to flow and cover the applied surface to form a bond. 2. Modulus of elasticity The modulus decided the de-bond ability of the adhesive without any kind of adhesive failure , like leaving residue on the applied surface. 3. Time , temperature and external strain. 3.(a).Time and Temperature Has direct effect on the performance of the PSA. Time and Temperature influence the flow characteristics of the PSA 3.(b).External strain. Tack depends on the peel off force and the speed of peel off. As the speed increases the tack value tends to increase. 28-01-2013 14
- 15. Adhesion : Tack, Tack isthe initial attraction of an adhesive to a substrate—the instant grab of the adhesive, with no external pressure applied. Sometimes tack is referred to as "quick stick" or "thumb appeal." Tack properties are typically measured using the loop tack test 28-01-2013 15
- 16. Adhesion : Peel Resistance, Peelis the force required to pull off the Adhesive from the applied surface The peel strength depends upon , 1.Viscosity Viscosity has a direct effect on the peel strength. As the viscosity increases the peel strength increases. 2.Modulus of elasticity The modulus decided the de-bondability of the adhesive. Lower the modulus , easier is the removability of the product. 3.Time , temperature and external strain. 3.(a ).Time and Temperature Has direct effect on the performance of the PSA. Time and Temperature influence the peel str . of the PSA. More the dwell time more is the peel , but the peel decreases as the temp increases. 3.(b).External strain. Peel depends on the speed of peel off . As the speed increases the peel value tends to increase.28-01-2013 16
- 17. Adhesion : Peel Resistance, Themeasure of bond strength between an adhesive and a substrate is defined as adhesion. It is important to note that this is the measure of bond strength after pressure is applied to the adhesive, allowing for wet-out onto the substrate. Adhesion properties are typically measured using the 180° or 90° peel adhesion test method 28-01-2013 17
- 18. Adhesion : Cohesive strengthor Shear resistance. Shear/cohesive is the holding power of adhesive is nothing but the resistance to shear stress. The shear depends upon 1.Viscosity Increase in Mol.wt of a polymer increases the viscosity .The increase in viscosity increases the shear strength. 2.Modulus of elasticity The modulus decided the de-bond ability of the adhesive without any kind of adhesive failure , like leaving residue on the applied surface. masticated rubber posses a lower elastic modulus as compared to raw rubber obtained from coagulated latex. The mastication processes reduces the modulus of the polymer but does not alter the Glass Transition Temp. the reduction is modulus , results in lowering the shear str. 3.Time , temperature and external strain. Shear resistance of an adhesive depends on it’s internal cohesion , which is a function of the inherent viscosity or modulus. Shear resistance is thus dependent on the factors affecting the viscosity and modulus.28-01-2013 18
- 19. Adhesion : Cohesive strengthor Shear resistance. The internal or cohesive strength of an adhesive film is known as shear. This is not a measure of the bond between the adhesive and a substrate, but rather a measure of the internal strength of the adhesive itself. Shear properties are typically quantified using the static shear test method 28-01-2013 19
- 20. The adhesive playsa very crucial role in terms of performance of the product. The real technology lies in striking a balance of the three main properties of adhesive , like the Peel strength , the tack and the shear strength. 28-01-2013 20
- 21. Co-related to Adhesives ,like WB Acrylic / GP HMPSA For application , such as Packaging Tapes 28-01-2013 21
- 22. Co-related to Adhesives ,like SB Acrylic For application , such as Application Tapes, holding Tapes, Foam Tapes 28-01-2013 22
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- 26. Further classification ofpressure sensitive adhesive ? Water-based PSA (WB PSA) – a PSA applied in aqueous emulsion form and dried to form the adhesive film Solvent-based PSA (SB PSA) – a PSA applied in solvent solution form and dried to form the adhesive film Hot-melt PSA (HM PSA) – a PSA applied as a 100% solids, thermoplastic composition in the molten state Calendered PSA – a PSA applied as a 100% solids composition in a calendering operation 28-01-2013 26
- 27. Water-based PSA (WBPSA) Rubber Latex Acrylic Nat. Rubber Latex Syn. Rubber Latex Ready to Use Modified / compounded 28-01-2013 27
- 28. Solvent-based PSA (SBPSA) Rubber Silicone Nat. Rubber Syn. Rubber SBR Butyl Acrylic Silicone Ready to use Acrylic Ready to use 28-01-2013 28
- 29. Hot-melt PSA (HMPSA) SIS EVA SBS SIBS PU 28-01-2013 29
- 30. Calendered PSA Rubber Nat. Rubber Syn.Rubber SBR Butyl 28-01-2013 30
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- 32. Water-based PSA (WBPSA) Rubber Base Ingredients Parts per 100 Adhesive Application Nat ./ Syn. Rubber Latex 100 Packaging Tapes Surface protection Tapes Sponge Rubber Tapes Tackifing Agent Dispersion 100 Rheology Modifier 001 Anti Foaming Agent 000.5 Cross Linking Agent 28-01-2013 32
- 33. Water-based PSA (WBPSA) Acrylic Ready to Use for BOPP / Paper Packaging Tapes Modified Acrylic Ingredients Parts per 100 Adhesive Application Acrylic PSA 100 Surface protection Tapes Foam Tapes HvAc Tapes , like Alu Foil , FSK , Alu Glass Tackifing Agent Dispersion 100 Rheology Modifier 001 Anti Foaming Agent 000.5 Cross Linking Agent 001 28-01-2013 33
- 34. Solvent-based PSA (SBPSA) Ingredients Parts per 100 Adhesive Application Nat ./ Syn. Rubber 100 Electrical insulation Tapes Surface protection Tapes Sponge Rubber Tapes Tackifing Agent 1 100 Tackifing Agent 2 080 Filler 030 Plasticizer 005 Cross Linking Agent 002 Suitable Solvent 100 28-01-2013 34
- 35. Suitable Solvents Solvent Chemicalformula Boiling point Dielectric constant Density Dipole moment Non-polar solvents Hexane CH3-CH2-CH2- CH2-CH2-CH3 69 °C 1.88 0.655 g/ml 0.00 D Benzene C6H6 80 °C 2.3 0.879 g/ml 0.00 D Toluene C6H5-CH3 111 °C 2.38 0.867 g/ml 0.36 D Polar aprotic solvents Ethyl acetate CH3-C(=O)-O- CH2-CH3 77 °C 6.02 0.894 g/ml 1.78 D Acetone CH3-C(=O)-CH3 56 °C 21 0.786 g/ml 2.88 D Polar protic solvents Ethanol CH3-CH2-OH 79 °C 24.55 0.789 g/ml 1.69 D Water H-O-H 100 °C 80 1.000 g/ml 1.85 D 28-01-2013 35
- 36. Hot-melt PSA (HMPSA) SIS ready to use EVA ready to use SBS ready to use SIBS ready to use PU ready to use 28-01-2013 36
- 37. Calendered PSA Rubber Nat. Rubber Syn.Rubber SBR Butyl 28-01-2013 37
- 38. Characteristic Rubber-Based AcrylicModified 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 Moderate Solvent resistance Poor Good Low/moderate Excellent Ultraviolet 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 28-01-2013 38
- 39. Types of PSA’coated products Tapes Labels Misc. Products 28-01-2013 39
- 40. Types of PSA’Tapes We are going to talk more about Tapes in this presentation Single Side Double Side Reinforced Unsupported With liner Without liner 28-01-2013 40
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- 42. PSA’ Tapes Single sideadhesive Without liner Adhesive Substrate With liner Adhesiv e Substrateliner 28-01-2013 42
- 43. PSA’ Tapes Double sideadhesive Adhesive Substrate Adhesive Release Liner 28-01-2013 43
- 44. PSA’ Tapes reinforced Adhesive ReleaseLiner Reinforcement 28-01-2013 44
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- 46. variety of PSA’Tapes Packaging Tapes Industrial Tapes Automobile Tapes Mounting Tapes Surface protection Tapes Electrical insulation Tapes Surgical Tapes Thermal insulation Tapes 28-01-2013 46
- 47. variety of PSA’Tapes Fabrics based Foam based Non woven based Metal foil based Film Based BOPP PVC Poly Ester Poly Ethylene Poly Amide Cotton Nylon Rayon Fiber Glass Aluminum Copper Paper based Kraft Crepe Poly Ester PP PU EVA Nitrile EPDM 28-01-2013 47
- 48. Double Coated Adhesive Tapes Unsupported AdhesiveTapes Foam Mounted Tapes & Sealing Products Label Base Stocks & Single Coated Adhesive Tapes 28-01-2013 48
- 49. Pressure sensitive adhesivetape manufacturing process ? Prior to the tape manufacturing process ,it is necessary to understand the characteristics of the PSAs , and the backing material / face stock / substrate and the conditions under which they will be used to satisfy end-use requirements without causing process ability concerns , And this will lead to a successful product. 28-01-2013 49
- 50. Surface Contour. Thecontour of the substrate will influence product selection (see Figure 3). For uses requiring conformability around irregular angles, more flexible materials should be employed. Regardless of the strength of the formulation, it is virtually impossible for an adhesive to overcome a continuous stress placed on it by a rigid material trying to return to its original form (memory). For such applications, one should choose a conformable product with a tissue or nonwoven carrier facestock or consider adding stress relief to the converted part via scoring or perforation. critical Issues are 28-01-2013 50
- 51. Surface Energy. Theability of an adhesive to wet out over the surface of a material is related to its surface energy. Low-surface-energy (LSE) materials do not allow the adhesive to wet out, whereas high-surface-energy materials allow excellent wet-out and provide the best adhesion. Rubber-based adhesives generally offer better adhesion to LSE substrates—a softer, better flow. Some materials require special treatment—corona treatment, primers, topcoats—to promote better adhesion. On some LSE materials, adhesion levels will improve with longer adhesive dwell times. critical Issues are 28-01-2013 51
- 52. PSA Tapes mainlyconsist of two main components , the carrier / backing material and the Adhesive. Generally Tapes are produced by coating a carrier ( or backing material ) , such as plastic films , fabrics, paper or foil with a adhesive , which is normally in liquid form. These adhesives contain solvents , such as water, or organic chemicals such as toluene, ethyl acetate etc, as carriers. The solvent is evaporated with help of hot air impregnation , so that a dry adhesive film is formed , above the backing material with a firm bond . In some cases the back-side of the tape is coated for non adhesive or release properties, which helps to have easy unwind property , with no adhesive transfer. 28-01-2013 52
- 53. The Backing material Thebacking material is the most important component of PSA Tapes . The backing or carrier provided the necessary strength and body to tape product. The backing has to be sufficiently strong . the backing needs to have reasonably good tensile strength , elongation , conformability, moderate heat resistance , chemical resistance, abrasion resistance etc. The various backing materials that are common in use are shown above. The backing materials need a primer coat or chemical or physical , surface preparation / treatment before adhesive coating. 28-01-2013 53
- 54. Surface Treatment Plastics Filmsare widely used in Packaging applications such as Self Adhesive Tapes, Laminates, Printing etc. As we know all these films are chemically inert and have very low surface energy. The below mentioned table gives an idea about the surface tension of various polymers. Sr.No. Polymer Surface Tension of Homo polymer in Dynes/Cm2 1 Poly Ethylene PE 31 2 Poly Propylene PP 32 3 Poly iso butylene PIB 27 4 Polystyrene PS 33 5 Poly Tetra Fluro Ethylene PTFE 19 28-01-2013 54
- 55. Surface Treatment From theabove tables it is very clear that the polymer surfaces need treatment to enhance the wettability , printability , and adhesion properties. Or in other words the surface tension has to match that of the coating materials. The common methods of surface treatment for films are chemical etching flame treatment carona treatment plasma treatment however chemical etching method is outdated. 28-01-2013 55
- 56. Surface Treatment Flame treatment Inthis process propane or butane flame is used to treat the polymer surface. Here the electron density is lower and therefore the ionization rate . The higher temp in the flame poses a problem for most polymer surfaces. Carona treatment Here the atmospheric air is ionized by help of high voltage transformer. The mechanism is like this. Two idler rollers form the two electrodes. High voltage of high frequency is produced with the help of a transformer. The high voltage applied to the two electrodes . one electrode ( Idler is insulated with silicone rubber coating , which is a perfect di electric. 28-01-2013 56
- 57. Surface Treatment Plasma Treatment Radiofrequency ( rf) glow discharge ( Cold gas plasma) of hydrogen in combination with vapourised liquid provides unique sueface modification. In this method gas molecules are excited by subjecting to an electric field , typically radio frequency energy. The radio frequency creates free electrons . these electrons gain energy from imposed field and collide with Nat gas molecules. The collision and transfer of energy form no of reactive species. These particles interact with solid surfaces placed in the plasma. This leads to dramatic modification of the molecular structure. Hydrogen in composition with liquid oxygen contributing co-reactant is used as the plasma. This creates stable oxygen moieties which is chemically reactive. This reactivity is ideal for forming tenacious bonds with selected adhesives. 28-01-2013 57
- 58. Advantages of plasma. gethigher treatment levels , upto 60 dynes/ cm2. no surface degradation low temp process the surface treatment has a long life back side treatment is eliminated treatment is permanent viable alternative for carona treatment is ineffective especially on PTFE electronic bombardment is 100% greater than carona. treatment is uniform through out the surface treatment on higher thickness , thicker than 0125 inch is possible. 28-01-2013 58
- 59. Surface Contamination. Thepresence of surface contamination such as skin oils and bodily fluids can prevent contact of the adhesive with the substrate. There are many different types of surface contamination, most of which are not visible to the eye but can be identified analytically. It may not be possible to obtain an acceptable bond without cleaning the surface (e.g., through washing or flame treating). Surface contamination may be present if one can detect loose material on the surface of a substrate or the material feels slippery, greasy, or slimy. Contamination may also be suspected if testing indicates poor bond strength and the adhesive feels "dead" after removal from the substrate. critical Issues are 28-01-2013 59
- 60. Pressure sensitive adhesivetape manufacturing process ? Adhesive Coating Rewinding and slitting or slicing Testing Packing Drying 28-01-2013 60
- 61. Adhesive Coating For Water borne/ Solvent borne adhesives 28-01-2013 61
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- 64. Coating machine Gravure Coating MethodCan handle Viscosity upto ( CPS ) Coating speed mtr/min Coating Weight ( gm/Sq.mtr.) Myer Bar 10-200 200 3.-25. Kiss 100-2000 700 3.-20. Gravure 100-2000 700 3.-20. 28-01-2013 64
- 65. Coating Method Canhandle Viscosity upto ( CPS ) Coating speed mtr/min Coating Weight ( gm/Sq.mtr.) Hot Melt 500-20000 300 10-300 28-01-2013 65
- 66. Coating machine with OnlinePriming 28-01-2013 66
- 67. Coating machine Comma /reverse roll Coating Method Can handle Viscosity upto ( CPS ) Coating speed mtr/min Coating Weight ( gm/Sq.mtr.) Comma / Reverse Roll 1000-6000 300 10-200 28-01-2013 67
- 68. Foam or Leather Sheetfeed adhesive coating Machine Coating Method Can handle Viscosity upto ( CPS ) Coating speed mtr/min Coating Weight ( gm/Sq.mtr.) Comma / Reverse Roll 1000-6000 300 10-200 28-01-2013 68
- 69. Foam or Leather Sheetfeed lamination Machine 28-01-2013 69
- 70. Hot Melt adhesive CoatingMc Roller Type Coating Method Can handle Viscosity upto ( CPS ) Coating speed mtr/min Coating Weight ( gm/Sq.mtr.) Hot Melt 500-20000 300 10-300 28-01-2013 70
- 71. Hot Melt adhesive CoatingMc Nozzle Type Coating Method Can handle Viscosity upto ( CPS ) Coating speed mtr/min Coating Weight ( gm/Sq.mtr.) Hot Melt 500-20000 300 10-300 28-01-2013 71
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- 73. Drying Drying of coatingsremoves the inert inactive solvent used to suspend , dissolve or disperse the active ingredients ( polymer , binder, pigments, slip agent, hardener , coating aids etc. ) , so that only the desired coating remains on the desired surface / substrate. Solvents could be water , or active organic materials Usually the drying process is a thermal one , in which heat is supplied , to the coated fluid and the solvent in it is vaporised. 28-01-2013 73
- 74. Drying Coating - DryingInteractions The purpose of drying process is to produce a uniform dry coating from the applied wet coating , by evaporation of solvent . If wet coating applied is uniform then the dryer must immobilize it and maintain its uniformity throughout the drying process. Drying and Coating processes are interdependent and interactive. The requirements of coating process determine the drying parameters. The needs and limitations of dryer influence the coating process. 28-01-2013 74
- 75. Drying A dryer designedto evaporate water differs significantly from one intended for use with volatile organic solvent. The bonder system influences the drying temp and air velocity. A low viscosity formulation is far more susceptible to damage in the dryer than a high viscosity one. Lower air viscosity must be used in the drying process to avoid moving the coating and damaging it. 28-01-2013 75
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- 80. Slitting / slicing Thethree most common slitting methods used are Razor , Shear , and Crush (score) 28-01-2013 80
- 81. Slitting / slicing RazerCutting 28-01-2013 81
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- 84. Slitting / slicing Machines SlittingMachine 28-01-2013 84
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- 88. Testing Peel strength / TensileStrength Shear test 28-01-2013 88
- 89. Please feel freeto contact us For more Information Our website : www.psadhesive.com Personal Email : psatechno@gmail.com Cell : 00 91 9850242282 28-01-2013 89