Plastisol

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Plastisol Plastisol1.JPG
Plastisol

Plastisol is a suspension of PVC or other polymer particles in a liquid plasticizer; it flows as a liquid and can be poured into a heated mold. When heated to around 177 degrees Celsius, the plastic particles dissolve and the mixture turns into a gel of high viscosity that usually cannot be poured anymore. On cooling below 60 degrees C, a flexible, permanently plasticized solid product results. [1] Aside from molding, plastisol is commonly used as a textile ink for screen-printing and as a coating, particularly in outdoor applications (roofs, furniture) and dip-coating.

Contents

Production

Pilot turbosphere (200 liters) equipped with water cooling system to produce plastisols. Turbosphere.jpg
Pilot turbosphere (200 liters) equipped with water cooling system to produce plastisols.

Uses

Textile ink

Plastisol is used as ink for screen-printing on to textiles. Plastisols are the most commonly used inks for printing designs on to garments, and are particularly useful for printing opaque graphics on dark fabrics.

Plastisol inks are not water-soluble. The ink is composed of PVC particles suspended in a plasticizing emulsion, and will not dry if left in the screen for extended periods. Garments don't need to be washed after printing. Plastisol inks are recommended for printing on colored fabric. On lighter fabric, plastisol is extremely opaque and can retain a bright image for many years with proper care.

Plastisol inks will not dry, but must be cured. Curing can be done with a flash dryer, or any oven. Most plastisols need to reach a temperature of about 180 degrees Celsius (350 Fahrenheit) for full curing. Plastisol tends to sit atop the fabric instead of soaking into the fibres, giving the print a raised, plasticized texture. Other inks can produce a softer feel.its also use for a high density print such as known as (HD) print . for this process have to do minimum 1 to 16 coats for a good HD print result and also have to bake after the print at 180 degree C for a long life better result

Slush molding

Plastisol is used for slush molding or slush casting, a form of spin casting that is more complex than simple resin casting, but less expensive and less sophisticated than the injection molding used for most plastic products. It involves metal molds that are filled with liquid plastisol. When the open mold cavities are filled, the mold is spun on a high speed centrifuge to force the liquid vinyl into the fine details on the interior of the mold. Then the metal mold is placed into a heating solution, usually an industrial salt heated to about 204 °C (400 °F). The liquid vinyl cooks for a few seconds. The mold is then removed from the heating solution and the remaining liquid is poured out. This leaves a thin skin of vinyl on the interior of the metal mold. The mold is then placed back into the heating solution for three to four minutes to cure. After curing, the mold is again removed from the heating solution, cooled with water, and placed on a rack. While the vinyl part is still warm in the mold, it is very flexible and can be removed from the mold with pliers. When the parts cool, they become rigid and are ready for assembly.

The metal molds can produce an unlimited number of castings. Unlike the flexible molds used for resin casting, metal molds are not adversely affected by heat. The metal molds allow grouping of several parts in one mold cavity and several mold cavities in one mold for faster production.

Solid rocket boosters

Plastisol process is used to bind polymer with metallic or metalloid agent and a liquid oxidizer, creating Electric Solid Propellant. This substance can be ignited and extinguished by electric impulse, providing pulsed rocket propulsion. With achievable pulse frequency reaching 60 Hz (60 ignition/extinguishing cycles per second), thrust of such boosters can be finely controlled; combined with possible minuscule dimensions, safety and low complexity it makes them usable as RCS thrusters of nanosatellites like the CubeSat. [2]

Polymer clay

Uncured plastisol is used as polymer clay ("Fimo"), a variety of modelling clay.

Road vehicles

Plastisol has seen limited uses as a material for the construction of lightweight road vehicles. The Optare Bonito minibus, launched in 2012, was the first commercial application of widespread plastisol construction in a road vehicle, although it failed to achieve any sales. Use of plastisol in road vehicle construction remains extremely limited as of 2019.

Soft Plastic Fishing Baits

Plastisol is used in the manufacturing of soft plastic fishing lures. Liquid plastisol is combined with various pigments, glitters, and powders, and is then injected into aluminum molds, forming soft lures effective in catching various species of fish.

Related Research Articles

Polyvinyl chloride Synthetic plastic polymer

Polyvinyl chloride colloquial: polyvinyl, vinyl; abbreviated: PVC) is the world's third-most widely produced synthetic plastic polymer. About 40 million tons of PVC are produced each year.

Screen printing printing technique

Screen printing is a printing technique where a mesh is used to transfer ink onto a substrate, except in areas made impermeable to the ink by a blocking stencil. A blade or squeegee is moved across the screen to fill the open mesh apertures with ink, and a reverse stroke then causes the screen to touch the substrate momentarily along a line of contact. This causes the ink to wet the substrate and be pulled out of the mesh apertures as the screen springs back after the blade has passed. One colour is printed at a time, so several screens can be used to produce a multi-coloured image or design.

Casting (metalworking) Pouring liquid metal into a mold

In metalworking and jewellery making, casting is a process in which a liquid metal is somehow delivered into a mold that contains a negative impression of the intended shape. The metal is poured into the mold through a hollow channel called a sprue. The metal and mold are then cooled, and the metal part is extracted. Casting is most often used for making complex shapes that would be difficult or uneconomical to make by other methods.

Thermoplastic plastic that becomes soft when heated and hard when cooled

A thermoplastic, or thermosoftening plastic, is a plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.

Thermosetting polymer polymer material that irreversibly cures

A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin. Curing is induced by heat or suitable radiation and may be promoted by high pressure, or mixing with a catalyst. Heat is not necessarily to be applied externally. It is often generated by the reaction of the resin with a curing agent. Curing results in chemical reactions that create extensive cross-linking between polymer chains to produce an infusible and insoluble polymer network.

Injection moulding injection molding process

Injection moulding is a manufacturing process for producing parts by injecting molten material into a mould, or mold. Injection moulding can be performed with a host of materials mainly including metals, glasses, elastomers, confections, and most commonly thermoplastic and thermosetting polymers. Material for the part is fed into a heated barrel, mixed, and injected into a mould cavity, where it cools and hardens to the configuration of the cavity. After a product is designed, usually by an industrial designer or an engineer, moulds are made by a mould-maker from metal, usually either steel or aluminium, and precision-machined to form the features of the desired part. Injection moulding is widely used for manufacturing a variety of parts, from the smallest components to entire body panels of cars. Advances in 3D printing technology, using photopolymers that do not melt during the injection moulding of some lower temperature thermoplastics, can be used for some simple injection moulds.

Sand casting Metal casting process using sand as the mold material

Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries. Over 60% of all metal castings are produced via sand casting process.

Compression molding

Compression Moulding is a method of moulding in which the moulding material, generally preheated, is first placed in an open, heated mould cavity. The mould is closed with a top force or plug member, pressure is applied to force the material into contact with all mould areas, while heat and pressure are maintained until the moulding material has cured. The process employs thermosetting resins in a partially cured stage, either in the form of granules, putty-like masses, or preforms.

Rotational molding

Rotational Molding involves a heated hollow mold which is filled with a charge or shot weight of material. It is then slowly rotated, causing the softened material to disperse and stick to the walls of the mold. In order to maintain even thickness throughout the part, the mold continues to rotate at all times during the heating phase and to avoid sagging or deformation also during the cooling phase. The process was applied to plastics in the 1950s but in the early years was little used because it was a slow process restricted to a small number of plastics. Over time, improvements in process control and developments with plastic powders have resulted in a significant increase in usage.

Spin casting, also known as centrifugal rubber mold casting (CRMC), is a method of utilizing inertia to produce castings from a rubber mold. Typically, a disc-shaped mold is spun along its central axis at a set speed. The casting material, usually molten metal or liquid thermoset plastic, is then poured in through an opening at the top-center of the mold. The filled mold then continues to spin as the metal solidifies.

Metal injection molding metalworking process

Metal injection molding (MIM) is a metalworking process in which finely-powdered metal is mixed with binder material to create a "feedstock" that is then shaped and solidified using injection molding. The molding process allows high volume, complex parts to be shaped in a single step. After molding, the part undergoes conditioning operations to remove the binder (debinding) and densify the powders. Finished products are small components used in many industries and applications.

Foundry factory that produces metal castings

A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools. The most common metals processed are aluminium and cast iron. However, other metals, such as bronze, brass, steel, magnesium, and zinc, are also used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed.

Fusible core injection molding, also known as lost core injection molding, is a specialized plastic injection molding process used to mold internal cavities or undercuts that are not possible to mold with demoldable cores. Strictly speaking the term "fusible core injection molding" refers to the use of a fusible alloy as the core material; when the core material is made from a soluble plastic the process is known as soluble core injection molding. This process is often used for automotive parts, such as intake manifolds and brake housings, however it is also used for aerospace parts, plumbing parts, bicycle wheels, and footwear.

Permanent mold casting is a metal casting process that employs reusable molds, usually made from metal. The most common process uses gravity to fill the mold, however gas pressure or a vacuum are also used. A variation on the typical gravity casting process, called slush casting, produces hollow castings. Common casting metals are aluminium, magnesium, and copper alloys. Other materials include tin, zinc, and lead alloys and iron and steel are also cast in graphite molds.

Casting Manufacturing process in which a liquid is poured into a mold to solidify

Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting materials are usually metals or various time setting materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods. Heavy equipment like machine tool beds, ships' propellers, etc. can be cast easily in the required size, rather than fabricating by joining several small pieces.

Resin casting is a method of plastic casting where a mold is filled with a liquid synthetic resin, which then hardens. It is primarily used for small-scale production like industrial prototypes and dentistry. It can be done by amateur hobbyists with little initial investment, and is used in the production of collectible toys, models and figures, as well as small-scale jewellery production.


Out of autoclave composite manufacturing is an alternative to the traditional high pressure autoclave (industrial) curing process commonly used by the aerospace manufacturers for manufacturing composite material. Out of autoclave (OOA) is a process that achieves the same quality as an autoclave but through a different process. OOA curing achieves the desired fiber content and elimination of voids by placing the layup within a closed mold and applying vacuum, pressure, and heat by means other than an autoclave. An RTM press is the typical method of applying heat and pressure to the closed mold. There are several out of autoclave technologies in current use including resin transfer molding (RTM), Same Qualified Resin Transfer Molding (SQRTM), vacuum-assisted resin transfer molding (VARTM), and balanced pressure fluid molding. The most advanced of these processes can produce high-tech net shape aircraft components.

Polymer solution casting is a manufacturing process used to make flexible plastic components which are typically in the shape of a single or multi-lumen tube commonly utilized in the medical device industry. This manufacturing technology is unique in that the process does not require conventional extrusion or injection molding technologies, yet it readily incorporates components and features traditionally produced by these processes.

Transfer molding is a manufacturing process in which casting material is forced into a mold. Transfer molding is different from compression molding in that the mold is enclosed [Hayward] rather than open to the fill plunger resulting in higher dimensional tolerances and less environmental impact. Compared to injection molding, transfer molding uses higher pressures to uniformly fill the mold cavity. This allows thicker reinforcing fiber matrices to be more completely saturated by resin. Furthermore, unlike injection molding the transfer mold casting material may start the process as a solid. This can reduce equipment costs and time dependency. The transfer process may have a slower fill rate than an equivalent injection molding processes.

In plastics processing, dip molding is a process of shaping of plastics by moulding. The coating of components with PVC has many applications. Plastic dip moulding is a technique where metal parts are coated with a plastic vinyl material. It is used to protect and make the metal parts more resistant to scratches and abrasions.

References

  1. Schey, J.A. "Introduction to Manufacturing Processes", The McGraw-Hill Companies (3rd Edition, 2000). Page 555.
  2. W. Sawka, M. McPherson "Electrical Solid Propellants: A Safe, Micro to Macro Propulsion Technology" 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference July 14–17, 2013, San Jose, CA. Retrieved on 1 July 2016