Thermoplastic adhesives .ppt

what are thermoplastic adhesives, types, properties, uses, its explanation with examples, use in the construction industry, applications, includes a market survey.

1. SUBMITTED BY: MAHIKA AGARWAL B.ARCH, 3 rd SEM THERMOPLASTIC ADHESIVES:

2. INTRODUCTION: Thermoplastic adhesives are plastic materials. The constituents of these adhesives are polymers that melt above a specific characteristic temperature and solidify upon cooling. The thermoplastic adhesive family also belongs to the hot-melt adhesives (HMAs). Thermoplastic adhesives can be applied as a molten liquid to encapsulate the fabric and then harden by cooling. These heat-activated adhesives generate joint strength almost instantly after cooling.

3. Thermoplastic adhesives  do not require a curing period. Instead, once the adhesive has been applied, it either cools (e.g., in the case of hot melt adhesives) or dries (e.g., in the case of glue) to form an adhesive bond between substrates . As thermoplastic materials do not require a curing period, they do not undergo a physical or chemical change upon the application of heat.  Therefore, they can be remelted and recycled for future attachment applications.

4. Some of the compounds from which thermoplastic adhesives are made include cellulose derivatives, polyacrylates, polyethers, polysulfones, saturated polyesters, and vinyl polymers and copolymers .

5. EXAMPLE: A good example of thermoplastic adhesive is hot glue used for crafts. The heat allows the chains to slide around much easier, and importantly, allow it to wet the materials that are being joined. Then once the adhesive cools, the chains grab onto each other again and the adhesive hardens, preventing the bonded materials from separating .

6. PROPERTIES: These adhesives hardens on cooling and soften when heated. They are fusible, soluble and poor heat and creep resistant. They have low/medium shear strengths and suffer from creep at high loadings. These are used for low/medium load assemblies. They have good resistance to oil and poor resistance to water. They are resistant to fungal attack and posses non-staining qualities.

7. Thermoplastic adhesives become deformable or flexible at relatively high temperature and melts when it is heated . It hardens into a vitreous transition state when it cools sufficiently (gluing). These are generally polymers with a high molecular weight , which have strong molecular bonds. After initial cooling and solidification , it can be heated and melted again, although its physical properties gradually change if it is melted several times.

8. USES: Used for woodwork glue. Used for joining metals and plastics. For fixing plastic laminates to wooden base. Used in packaging industry. Profile wrapping, product assembly. Laminating applications in wood work industry. Also many electronic manufacturers use them to affix parts and wires, to secure, insulate and protect the device’s components. Fabrication of furniture.

9. TYPES: Cellulose acetate. Cellulose acetate butyrate. Cellulose nitrate. Polyvinyl acetate. Polyamide. Acrylic.

10. CELLULOSE ACETATE AND CELLULOSE ACETATE BUTYRATE : Cellulose acetate and cellulose acetate butyrate are water clear and more heat resistant, but less water resistant, than cellulose nitrate . Cellulose acetate butyrate has better heat and water resistance than cellulose acetate and is compatible with a wide range of plasticizer .

11. CELLULOSE NITRATE: Cellulose nitrate is used as a raw material for solvent adhesives . Cellulose nitrate mixed with alcohol is well known as collodion . The adhesive film developed by cellulose nitrate is resistant to water but affected by strong acids and alkalies and aging. It is inflammable and in recent years it is replaced by others. Uses: As multipurpose adhesive, shoe adhesive .

12. POLYAMIDES: Polyamides are able to create a strong bond between several different types of substrates, including paper, wood and metal as well as plastics like treated polypropylene and polyethylene, ABS and vinyl. Some types of polyamides can even adhere PVC, which can be difficult to bond reliably . In many applications, polyamide hot melts offer an ideal blend of strength, flexibility, resistance to oils and chemicals and ease of use . USES: Used in wood working, furniture building and electrical.

13. ACRYLIC: An acrylic adhesive is a resin-based adhesive comprised of acrylic or methylacrylic polymers . They are extremely strong and efficient in bonding multiple objects together and are very environmentally resistant. Because of this environmental resistance, acrylic adhesives are often the preferred adhesive in the construction industry . In window mount bonding and sealing, sign making etc. USES :

14. THERMOPLASTIC ADHESIVE : POLYVINYL ACETATE (PVA): As an emulsion in water, PVA is sold as an adhesive for porous materials , particularly wood , paper and cloth . It is the most commonly used wood glue, both as the “white glue”, and the yellow “carpenters glue”. It is available in liquid form. Its curing time is 20 minutes along with pressure.it can be stored in cool areas, freezing should be avoided .

15. HOW PVA’s ARE USED? For onsite applications, squeeze bottles, paint rollers, or stiff bristle brushes offer convenient means of application. Some formulations are also adaptable to spraying. ADVANTAGES : Ready to use or requiring only limited mixing. Can be easily applied. Set rapidly at room temperature. Cure to a colourless bondline .

16. DISADVANTAGES: They tend to creep in stressed joints. Are even more subject to deformation at temperature above 49 deg celsius sor sustained periods. Possess only fair water and moisture resistance. USES: As wood glue. As paper adhesive during paper packaging conversion. In bookbinding and book arts, due to its flexible strong bond and non acidic nature .

17. In handicrafts. As wallpaper adhesive. As a primer for drywall and other substrates. As envelope adhesive.

18. ADVANTAGES: Vibration and noise damping. Insensitivity to corrosive environment   Direct and indirect reduction in joint weight. Higher chemical resistance against acids, bases, and alcohols, good resistance to moisture Electrical insulation Chip resistance Aesthetically-superior finishes Superb corrosion resistance

19. DISADVANTAGES:   They exhibit lower heat (i.e., lower operative maximum temperature) and strength resistance. May soften when reheated. Can be more expensive than thermoset. It tend to form weaker adhesive bond. Limited service temperature performance.

20. PERFORMANCE OF THERMOPLASTIC ADHESIVES: The performance is consistent and reproducible than thermosets for fundamental reasons. Thermoplastic, fully polymerized by manufacturer under highly controlled conditions of temperature, pressure , reaction rate and time. Thermoplastic adhesives can be bonded in a dry state which significantly reduces the possibility of voids so often experienced with epoxies and polyimide thermosets .

21. MARKET SURVEY: Polyfix Cyanoacrylate Glue Instant Bond: Price : ₹ 5/  Piece Brand – Polyfix Packaging Size - 0.500Mg Grade Standard - Industrial Grade,Cyanoacrylate Glue Features - Impact Resistant,Instant Curing Surface of Application - Household Product, Helmet, Metal Minimum Order Quantity - 50 Piece Supplier - Benson Polymers Ltd. 

22. Hardybond PVC WPC Adhesive : Price - ₹ 85/  Unit Brand – HARDYBOND Packaging Size - 20 ml Packaging Type – Pack Application Industry - Construction, WPC FURNITURE Surface Of Application – Plastic Form – Liquid Grade Standard – Chemical Strength – High Country of Origin - Made in India Minimum Order Quantity - 100 Unit Supplier - Hardy Smith Designs Private Limited

23. Superfix PVC Solvent Cement - 10 ml-5000 ml: Brand Superfix Grade Standard Industrial Grade Packing Type Plastic Bottle Form Liquid Packaging Size 500 ml and 250 ml Usage Prize Supplier Industrial ₹ 6.5 / piece Innomax industries, new delhi .

24. 1000mL PVC Solvent Cement: ₹ 115/  Piece  : Brand Aster Bond Grade Standard Industrial Grade Packaging Size 1000 ml Packaging Type Tin Form Liquid Surface Of Application Plastic Shelf Life 2 Year Minimum Order Quantity Supplier 60 Piece Sahjanand industries, Ahmedabad

25. Super m 250 ml Heavy Duty PVC Pipe Solvent Adhesive, Tin Can: ₹ 44/  Can   : Surface Of Application PVC Brand Super m Packaging Size 250 ml Packaging Type Tin Can Form Liquid Shelf Life 2 Years Country of Origin Supplier Made in India Akhar industries, ahmedabad

26. Ethyl-cyanoacrylate Super Bond Instant Glue for Plastic, ₹ 10/  Piece:   Packaging Size 10 ml to 100 ml Material Ethyl-cyanoacrylate Grade Standard Chemical Grade, Industrial Grade Usage/Application Plastic Packaging Type Bottle Form Liquid Color Transparent Fixture Time 1/2 sec Minimum Order Quantity 500 Piece

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