PLASTICS, TEXTILES,
STONES AND CERAMICS
UNIT 3
3º ESO BILINGUAL
IES MIGUEL ESPINOSA
TECHNOLOGIES
PLASTICS, TEXTILES, STONES
AND CERAMICS
-ORIGIN
-PROPERTIES
-TRANSFORMATION
PLASTICS
-PHYSICAL
-ECOLOGICAL
CLASIFICATION
THERMOPLASTICS
THERMOSTABLE
ELASTOMERS
FORMATION
TECHNIQUES
-EXTRUSION
-LAMINATION
-VACUUN
FORMING
-MOULDING
SHAPING
AND
FINISHING
TECHNIQUES
-CUTTING
-PERFORATING
-TRIMMING AND
TRIMMER
JOINING
PLASTICS
-TEMPORARY UNIONS
-PERMANENT UNIONS
1. PLASTICS
1. ORIGIN
� PLASTICS, FOR THEIR PROPERTIES,
AVAILABILITY, TRANSFORMATION PROCESS AND
PRICES, ARE THE MATERIAL OF THE FUTURE.
� PLASTICS ARE MATERIALS FORMED BY
POLYMERS.
� THE POLYMERS IN PLASTICS ARE MADE FOR
LONG CHAINS OF CARBON ATOMS.
1. PLASTICS
� CLASIFICATION OF PLASTICS DEPENDING ON
THEIR ORIGIN:
- NATURAL PLASTICS: are obtained directly from raw
vegetable materials. Examples: cellulose and latex,
from animal protreins.
- SYNTHETIC PLASTICS: are made from compounds
extracted from petroleum, natural gas and coal.
Chemical process.
1. PLASTICS
� The transformation of these raw materials and
compounds into plastics is called polymerisation.
� Different plastics?
- During the manufacturing process, we can add
materials such as fibreglass, textile fibres, paper,
silicia and sawdust to reduce production costs, and to
develop certain characteristics.
- We can incorporate chemical additives to increase
flexibility and to strengthen the polymers, and we can
add pigments to give colour to the plastics.
1. PLASTICS
2. PROPERTIES OF PLASTICS
� The properties of plastics depend on their type and
their composition.
� Similar characteristics of many plastics:
- Strength
- Elasticity
- Rigidity
- Flexibility
* Although they vary from one type to another.
1. PLASTICS
� Common properties to the majority of plastics:
- mechanical: malleability, ductility, mechanicalresistance.
- Acoustic: acoustic insulation.
- Electrical: electrical insulation.
- Thermal: thermal insulation.
- Other properties: low density, impermeability.
Activity: look for the definition of each property (12: Strength, Elasticity, Rigidity, Flexibility, malleability, ductility, mechanicalresistance, acoustic insulation, electrical insulation, thermalinsulation, low density, impermeability)
1. PLASTICS
3. ECOLOGICAL PROPERTIES
Plastics contaminate a lot!!!
We can recycle plastics.
There are three recycling processes:
- Chemical recycling: we apply chemical processes to
make new materials from the original components of
plastic residues.
1. PLASTICS
- Mechanical recycling:
We make new products from plastic granules. Theprocess has five stages:
1. Separation and crushing � according to their type.
2. Floating. Wash and dry (centrifugal force).
3. Agglutination. The material is compacted and thenincorporated into other materials.
4. Extrusion. To melt the material � extruded into long filaments.
5. Pelletising. The filaments are then reduced togranules that we call pellet.
1. PLASTICS
- Energetic recycling. We can incinerate plastics and
the energy that is produced and used in industry, for
heating or producing electricity.
* Biodegradable: the majority of plastics are not.
2. CLASSIFICATION OF PLASTICS
ACCORDING TO ITS STRUCTURE:
2.1 Thermoplastics
2.2 Thermostable
2.3 Elastomers
2. CLASSIFICATION OF PLASTICS
2.1. Thermoplastics
From compounds acquired from petroleum.
When we heat them, they become soft���� which allows them to
be formed into different shapes.
The heating and cooling process can be repeated many times.
Made up and formed of weakly molecular chains.
2. CLASSIFICATION OF PLASTICS
Thermoplastics examplesPVC: Cloruro de polivinilo *
Strong. Waterproof. Durable.
Uses: tubes and pipes. Shoe soles. Gloves.
Waterproof clothing. Hosepipes.
PS: Poliestireno *. Two types:
a) Hard: Transparent. Can be coloured.
Uses: CD cases. Coat hangers.
Dairy products containers. Egg boxes.
b) Expanded (porexpan): porous. Soft.
Uses: packaging. Thermal and acoustic insulation.
PE. Polietileno. Two types:
High density (HDPE)*: Rigid. Resistant. Transparent.
Low density (LDPE)*. Soft. Light. Transparent.
Uses: transparent packaging film. Bags. Cups and plates.
* ���� Recyclable plastic
2. CLASSIFICATION OF PLASTICS
Thermoplastics examplesPP. Polipropileno *
Flexible. Resistant to chemicals. Hard surface.
Uses: bottles and containers. Ropes. Bags.
Metacrilato*. Plexiglas. Transparent.
Uses: car headlights. Windows. Illuminated signs.
Goggles. Watches.
Teflón* non-stick. High heat resistance.
Uses: kitchen utensils. Paints. Aircraft and rocket exteriors.
Celofán (Biodegr.)
Transparent. Flexible. Resistant. Shiny. Adhesive.
Uses: packaging. Wrapping.
Nailon o Poliamida. Translucent. Shiny. Resistant.
Flexible. Waterproof.
Uses: fabrics. Toothbrushes. Tennis racket strings.
* ���� Recyclable plastic
2. CLASSIFICATION OF PLASTICS
2.2. Thermostable plastics
Made from compounds derived from petroleum.
Formed by strongly-linked chains running in different directions.
When heated, they become soft and can be shaped.
When cooled, they cannot be remoulded by applying heat.
2. CLASSIFICATION OF PLASTICS
Thermostable plastics:
Poliuretano (PUR)
Porous and flexible. Soft and dense.
Elastic and adhesive.
Uses: foam rubber for cushions. Sponges.
Thermal and acoustic insulation.
Glues and varnishes.
Resinas Fenólicas (PH). Baquelitas
Dark colours. Electric insulator.
+Fibreglass�Shock resistant.
+Asbestos (Amianto)� Heat resistant.
Uses: kitchen utensil handles.
Covers for electrical insulation.
Electric plugs and switchs.
2. CLASSIFICATION OF PLASTICS
Thermostable plastics:
Melanina
Light. Hard resistant. Tasteless and odourless.
Thermal insulator.
Uses: Small electric objects.
Thermal and acoustic insulation.
Kitchen surfaces. Plates and food containers.
Resinas de poliéster (UP)
Heat resistant (200 ºC)
Reinforced by fibre-glass for strength
and rigidity.
Uses: crash helmets. Bodywork for cars and
boats. Fishing rods.
2. CLASSIFICATION OF PLASTICS
2.3. Elastomers
Made by vulcanisation.
Vulcanisation: Charles Goodyear (1800-1860). Mixing sulphur and
rubber to 160 ºC� become hardness, resistance and durability
without losing its natural elasticity.
Formed by chains linked laterally and then folded over
themselves.
Hard, resistant and very elastic – stretching easily under force..
2. CLASSIFICATION OF PLASTICS
Elastomers:
Caucho natural (natural rubber)
From latex. Resistant and inert.
Uses: thermal and electrical insulation.
Mattresses. Tyres.
Synthetich rubber (polymer)
From petroleum. Resistant to chemicals.
Uses: tyres, steering wheels. Gloves.
Mattresses.
Neopreno
From synthetich rubber. Harder and more resistant
than synthetich rubber. Waterproof.
Uses: diving suits. Hosepipes. Gloves.
Mattresses: colchones Tyres: neumáticos -Wheels: ruedas steering wheels: volantes
3. FORMATION TECHNIQUES
� The plastic used to manufacture objects is available in three
different forms: powder, granules and resins.
� We can use different formation techniques depending on
the type and use of the plastic.
3. FORMATION TECHNIQUES
� EXTRUSION
� This technique has four steps:
1. We put thermoplastic, in granular form, into a previously heated
cylinder.
2. We apply pressure by means of a large, rotating screw, which forces the
melted material out, through a nozzle.
3. We cool the shaped material slowly in a refrigerated water bath until
it´s solid.
4. Finally, we collect the pieces of plastic through a feeder system.
Used to form: wrapping, lining for electric wires, tubes and pipes.
extrusiónNozzle: inyector
Feeder: alimentador
Wrapping: envoltura
3. FORMATION TECHNIQUES
� LAMINATION� Thermoplastic produced by the extrusion method is passed through a
series of hot cylinders to produce sheets of varying thickness.
� We can produce different finishes (glossy, matt or textured), depending
on the outer coating applied by the final cylinder.
� Applications: kitchen furniture, worktops, to cover surfaces of kitchen
and drawers.
calandrado.JPG
calandrado 2
Sheets: láminas, hojas.
Thickness: grosor
Glossy: liso, brillante.
3. FORMATION TECHNIQUES
� VACUUM FORMING
� For plastic sheets with a large surface.
� Steps:
1. Put a thermoplastic sheet into a mould.
2. Use a heater to heat the mould and soften the plastic.
3. Extract the air below the sheet so that the plastic is pulled against the
inside walls of the shaped mould, and the desired form is created.
4. Leave the mould to cool, then remove the object.
Applications/ Used to form: bathtubs, dashboards, shop signs and egg
boxes.
Conformado al vacío1 Conformado al vacío2
Vacuum forming: conformado al vacío
Bathtubs: A bathtub is a long, usually rectangular container which you fill with
water and sit in to wash your body.
Dashboard: salpicadero
3. FORMATION TECHNIQUES
� MOULDING
A hollow container or mold with the final form of the wished product IS
used as counterfoil in order to make the plastic acquire the form of
the above mentioned interior surface
There are three principal techniques:
1. Inyection
2. Blow moulding
3. Compression
Counterfoil: matriz
To spill: verter
3. FORMATION TECHNIQUES
� Blow moulding
1. We put a tubular-shaped piece of
plastic (from extrusion) into a
hollow mould which has the same
shape as the object that we want
to make.
2. We close the mould and blow
pressurised air into it, so that the
plastic adheres to the sides of the
mould and takes its shape.
3. When the object is cold, we
remove it from the mould.
Used to form: hollow objects (bottles and flasks)
Hollow: object that has an empty space or cavity inside. Flasks:
frascos.
3. FORMATION TECHNIQUES
� Injection moulding
1. We inject melted material into a mould.
2. When the material has cooled and solidified, we extract it from the
mould.
Used to form: domestic utensils such as buckets and containers, vehicle and
aircraft components.
Bucket: round container with a flat botton for water and other fluids.
3. FORMATION TECHNIQUES
� Compression
1. We put thermostable plastic in granular form into the base of a cavity
mould.
2. The outer part of the cavity mould, shaped the same, is closed to
compress the material inside. Then we heat it and it becomes soft and
malleable.
Used to form: different types of containers, machine bodywork and electrical
appliances.
3. The plastic adapts to the shape of the
cavity between the two parts of the
mould.
4. We extract the object when the plastic
has cooled and solidified..
4. SHAPING AND FINISHING TECHNIQUES
We can use different tools and machines to finish the plastic objects that
have made.
Principal techniques: cutting, perforating, trimming and filing.
4. SHAPING AND FINISHING TECHNIQUES
CUTTING:
- Cutter
- Scissors
- Steel bit
- Feetsaw
- Jig saw
�To cut sheets of different thickness, depending on
their hardness.
�To cut soft, thin and flexible sheets.
�To cut sheets less than 1 mm in thickness.
�To cut soft, low density plastics. Can make straight,
slanting and curved cuts.
� to cut very large sheets of plastic, and rigid plastics
in general. Can make straight, slanting and curved cuts.
4. SHAPING AND FINISHING TECHNIQUES
CUTTING
- Power press
- Hot metal thread trimmer
� to cut flat sheets of low density plastic. Makes
simple objects by applying preasure.
� to cut sheets of soft thermoplastic. (poliestireno
expandido or porexpan)
4. SHAPING AND FINISHING TECHNIQUES
PERFORATING:
- Drill bit�Tool that makes holes in plastics.
Consists of inserting a long, thin, round and
threaded piece of metal into the head of the
machine that envolves high speed for cutting
holes.
4. SHAPING AND FINISHING TECHNIQUES
TRIMMING AND FILING:
- Lima y Escofina
A file has a rough surface.
Used to finish the surfaces and edges of hard materials.
A rasp has an even rougher surface, covered with “teeth”.
Used to finish the surfaces and edges of soft materials.
5. JOINING PLASTICS
Una vez manipulados, los plásticos pueden juntarse mediante uniones
desmontables o fijas.
5.1. Uniones desmontables
Permiten la unión y separación de las piezas mediante elementos roscados
que impiden la rotura del plástico.
Son:
-Tornillo pasante con tuerca.
-Tornillo de unión.
-Enroscado.
5. JOINING PLASTICS
5.2. Uniones fijas
Se usan cuando no se prevé la separación o desmontaje ya que no se
pueden separar sin que se produzca la rotura de los elementos.
Los plásticos se pueden unir mediante adhesivos o soldadura.
-Adhesivos: unión permanente cuando se interpone entre dos
superficies. Pueden ser resinas, cemento acrílico o adhesivos de
contacto.
-Soldadura: unión por medio de calor y presión. Es muy utilizado el
método de mordazas calientes.