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Adhesives - high strength glues used to join things together.

Adhesives - high strength glues used to join things together. INTRODUCTION. can be just as tough and durable as welds,rivets or bolts. . form a bond by filling in the minute pits and fissures normally present even in very smooth surfaces. Adhesive bonds are :- economical

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Adhesives - high strength glues used to join things together.

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  1. Adhesives -high strength glues used to join things together. INTRODUCTION can be just as tough and durable as welds,rivets or bolts. form a bond by filling in the minute pits and fissures normally present even in very smooth surfaces. • Adhesive bonds are :- • economical • distribute the stress at the bonding point • resist moisture and corrosion • eliminate the need for rivets and bolts.

  2. Archaeologists have found 6000-year-old ceramic vessels that had broken and been repaired using plant resin. H I S T O R Y • The first adhesives were natural gums and other plant resins. Resin of a pine tree • Most early adhesives were animal glues made by rendering animal products such as the Native American use of buffalo hooves. • Egypt was one of the most prominent users of adhesives. Egyptians used animal glues to adhere tombs, furniture, ivory, and papyrus. Buffalo hooves

  3. CLASSIFICATION

  4. NATURAL Natural adhesives are those which are obtained from animal gelatins, vegetables and starches Types of natural adhesive • Animal • Casein • bituminous ADHESIVE Animal- made from the hides, hoofs and bones of animals. available in cake or more likely supplied in small beads. essential for restoration work, veneering and other applications where compatibility with original artifacts is needed. used extensively in the musical instrument industries. hides of animals

  5. CASEIN- Manufactured from soured, skimmed milk curbs, which are dried and crushed into a powder form. General joinery and woodwork use. To use the powder it is mixed with cold water into a smooth creamy paste. NATURAL ADHESIVE Bituminous- Bitumen may be defined as a non crystalline, solid or viscous material derived from petroleum. It is asphalt in solid state and mineral tar in semi fluid state. Bitumen jointed setts

  6. These are transformed into tough, heat-resistant solids by the addition of a catalyst or the application of heat. used in such structural functions as bonding metallic parts of aircraft and space vehicles. Eg.- epoxy cements, urea formaldehyde, melamine formaldehyde, polyester and silicon adhesives. THERMOSETTING ADHESIVES

  7. UREA FORMALDEHYDE THERMOSETTING ADHESIVES • More familiar to the cabinet and woodworker under the trade name 'Extramite'. • Used when a high quality but stable fix is required. • Sets at normal room temperatures and is relatively cheap and available. • Suitable for laminating, fabricating and veneering when large presses or good cramping facilities are available Adhesive being applied on veneers

  8. PHENOL FORMALDEHYDE (PH) THERMOSETTING ADHESIVES • Used where great strength is required, durable and water resistant. • An 'engineering adhesive' used for heavy structural work and quality Melamine formaldehyde (MF) • Amore expensive adhesive usually used as an additive. • Used in the production of hard decorative plastic laminates.

  9. RUBBER ADHESIVE THERMOSETTING ADHESIVES made by dissolving rubber in benzene. have excellent property of forming rigid bonds. This enable the adhesive the adhesive to flex and stretch under stress and recover to its original position as soon as the load is removed. have high bond strength and durability. Reclaimed natural rubber adhesive has the advantage flow cost as automobile tyres form the largest source of reclaimed rubber of making of adhesives

  10. Polyvinyl acetate (PVA) THERMOPLASTIC ADHESIVES • can be softened by heating, • used for bonding wood, glass, rubber, metal, and paper products. EX- neoprene, polyvinyl acetate and acrylic adhesives. • (White Glue) • It can be used on all woods, soft, hard, chipboards, plywood, etc. • A good general-purpose woodwork adhesive for indoor use only.

  11. ADVANTAGES • adequate strength is produced • it is possible to have a wide variety of combinations in joining. • a massive effect is created. • corrosion may be prevented between different metals joined by adhesive. • The surface of plastics, wood metals are joined by adhesive. • application process is economical, easy and speedy. • adhesives joints , impermeable for water and gas can be made.

  12. DISADVANTAGES • Unsuitable at high temperatures. • An adhesive requires sometime to attain the desired strength. • Specific adhesive is required to be used for specific substance

  13. PROPERTIES should have :- • high tensile strength • strong cohesive strength • adherence • fluidity • wettability

  14. HOW ADHESIVES • By loss of solvent Either evaporation of the solvent as in the case of contact adhesives or by the absorption into the timber in the case of emulsion (PVA) adhesives. • By cooling. Adhesives applied in a molten condition solidify on cooling. This has the advantage of a very fast set. WORK

  15. SYNTHETIC RESIN ADHESIVE PRODUCTS Use :- For bonding wood, ply woods, laminates , veneers, particles boards, block boards, hard boards and MDF to each other with superior water resistance and faster drying time • Featuers and benefits :- • specialized water resistant adhesive that protect furniture from water • 48 hour continuous cold water & 1hour boiling water resistance • Its special chemical properties gives superior bonding with adhesive, ply to laminate

  16. SYNTHETIC RUBBER ADHESIVE PRODUCTS Features and benefits :- • Multi purpose adhesive • Ideal viscosity gives superior coverage • Excellent bonding strength • Does not contain benzene

  17. PRODUCTS

  18. Tile fixing adhesive PRODUCTS Areas of Usage :- Used for vertical cladding In kitchens,smming pools, floors, bathrooms, terraces and dado areas

  19. APPLICATION METHODOF • The surface to be tiled should be sound and thoroughly cleaned. • Old surface should be free from wax, grease, polish, etc. • POUR 25 kg. bag in approx 8 lit. of clean water proportion approx. 3:1 of powder to water by volume) addition of water shall be adjusted to attain desired consistency.

  20. Mix with a trowel/slow speed drill (50-100 rpm) until a lump-free homogeneous paste is obtained • Spread the adhesive to a thickness of approx. 3 TO 5 mm and comb with a notched trowel • Start placing the marble or granite tiles on vertical surface . • Tap the tiles properly to ensure complete coverage of the backside of tiles and to eliminate the possibility of any air voids APPLICATION METHODOF

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