Glass Packaging PDF

GLASS PACKAGING OUT 1 INTRODUCTION 2 COMPOSITIONS AND PROPERTIES OF GLASS 3 MANUFACTURING OF GLASS CONTAINERS LINE TODAY'S 4 5 CLOSURE FOR GLASS CONTAINERS ADVANTAGES AND DISADVANTAG...

GLASS PACKAGING OUT 1 INTRODUCTION 2 COMPOSITIONS AND PROPERTIES OF GLASS 3 MANUFACTURING OF GLASS CONTAINERS LINE TODAY'S 4 5 CLOSURE FOR GLASS CONTAINERS ADVANTAGES AND DISADVANTAGES OF GLASS CONTAINERS AGENDA CLASS OBJECTIVES EXPECTATIONS AND OUTCOMES Able to discuss he factor of selecting Able to describe glass compositions closure for glass containers. and properties as well as glass Able to list out pro and cons of glass manufacturing process. containers. INTRODUCTION “an amorphous inorganic product of fusion that has been cooled to a rigid condition without crystallising” ASTM GLASS COMPOSITIONS * Basic structural unit: silicon-oxygen tetrahedron Si atom surrounded by four O2 atoms. * Basic raw materials: mines or quarries – reduces oxides at 1500°C * Principle ingredients: silica (derived from sand flintz, quartz) * Alkali fluxes: sodium/pottasium carbonates – lower the fusion temperature and viscosity of silica * Calcium and magnesium carbonates (limestone and dolomite): act as stabilizers * Lead – clarity & brilliance * Alumina – hardness and durability * Boron – reduce leaching GLASS PROPERTIES MECHANICAL When force is applied – glass usually breaks because of its amorphous structure * (brittle) Presence of surface flaws eg. microcracks/scratch/checks (stress concentrator) – * found mostly at glass surface which occur during manufacturing process or from careless handling. GLASS PROPERTIES PHYSICAL Internal Pressure Resistant Internal pressure produces bending stresses at various points on outer surface of glass. Important for carbonated beverages bottles & bottles processed in boiling water/ pressurised hot water. GLASS PROPERTIES PHYSICAL Resistance to Impact Two forms of impact: Moving bottle contacting stationary object (eg. bottle dropped) Moving object contacting stationary bottle (eg. filling line) Design features - to strengthen contact points of bottle sidewall. Surface treatments to lessen fragility of glass. GLASS PROPERTIES PHYSICAL Vertical Load Strength Glass can resist severe compression. Design of shoulder is important to minimise breakage during high speed filling and sealing operations. GLASS PROPERTIES PHYSICAL Resistance to Scratches & Abrasions Overall strength of glass can be significantly impaired by surface damage especially for thin-walled bottles (one-trip bottles). Surface treatment involving tin compounds (or other treatments) to provide scuff resistance. GLASS PROPERTIES THERMAL * Resistance to thermal failure depends on: Type of glass used Shape of the container Wall thickness * Stresses occur due to differences in expansion & shrinkage rate. * Sudden heating leads to surface compression and internal tension - temporary and disappear when equilibrium temperature reached. * Sudden cooling much more damaging than sudden heating. GLASS PROPERTIES OPTICAL * Optically isotropic – no crystalline structure. * (US Pharmacopeia) Light resistant container: passes no more than 10% of incident radiation at any wavelength between 290 and 450 nm through average sidewall thickness * Light transmission controlled by addition of colouring additives. GLASS MATERIALS Mines / Quarries Silica sand Dolomite Quartz GLASS MANUFACTURING Blow and Blow (B&B) 01 Press and Blow (P&B) 02 Narrow Neck Press and Blow (NNPB) 03 01 BLOW AND BLOW (B&B) Glass Bottle 02 PRESS & BLOW PROCESS (P&B) Glass Jar 03 NARROW NECK PRESS AND BLOW (NNPB) Glass Bottle CLOSURE FOR GLASS CONTAINER Factors to be considered in selecting closure Seal effectiveness: prevent loss of contents or prevent penetration of substance from outside. Easy opening & re-closing: provide good re-seal. Dispensing: easy for consumer to reach the content. Decorative effect: should harmonise with the container also add sales appeal. Packaging line: not too complicated to be applied. Product compatibility: closure material should not react with container content. Cost: not too expensive. Evidence of inviolability/tampering – roll-on pilfer proof (ROPP) closures. CLOSURE FOR GLASS CONTAINER Actual sealing components of closure must have intimate contact with glass finish to form effective seal. Gasket made of rubber/plastisols used for vacuum closures and heat-processed food containers. Liner Cushioning material (wad) with a facing material to isolate content from contact with wad. Usually made of paperboard, coated with plastic/metal foil  CLOSURE FOR GLASS CONTAINER Type of closures according to its function: to contain and protect content to retain internal pressure to secure content inside container to maintain vacuum inside container  PROS CONS AND ADVANTAGES DISADVANTAGES Abundant raw materials. Accepted as safest packaging materials. Tendency to shatter: due to physical, mechanical Inert: no detectable reaction to organic liquids (eg.oils abuse or sudden change in temperature. & solvents) but hydrofluoric acid is the only liquid which reacts rapidly with glass at room temperature. Heavy weight: transportation cost. Impermeable: good barrier to water & gas. No odour. Lack of flexibility: rigid structure. Rigid: easy to handle on filling line & retain its shape during all phase of marketing. Consumer unfriendly: broken glass inside products. Combined with foil to make effective tamper-evident container. Re-sealable: unused products can be kept and saved for future use. Transparent: able to showcase products & entice buyer. Creative shape & design: attractive to consumers also as crafts or collectibles after product used up. Recyclable: does not pollute / environmental friendly.