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. 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.
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.
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.
Uncured plastisol is used as polymer clay (“Fimo”), a variety of modelling clay.
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.
Nylon 11 or Polyamide 11 (PA 11) is a polyamide, bioplastic and a member of the nylon family of polymers produced by the polymerization of 11-aminoundecanoic acid.
It is produced from castor beans by Arkema under the trade name Rilsan. Nylon 11 is applied in the fields of oil and gas, aerospace, automotive, textiles, electronics and sports equipment, frequently in tubing, wire sheathing, and metal coatings.
History of Nylon
In 1938, a research director for Thann & Mulhouse, Joseph Zeltner, first conceived the idea of Nylon 11, which was suggested in the works of Wallace Carothers. Thann & Mulhouse had already been involved in processing castor oil for 10-undecenoic-acid, which would eventually be converted into the first amount of 11-aminoundecanoic acid in 1940 with the help of coworkers Michel Genas and Marcel Kastner. In 1944, Kastner sufficiently improved the monomer process and the first patents for Nylon 11 were filed in 1947. The first nylon 11 thread was created in 1950 and full industrial production began with the opening of the Marseilles production facility in 1955, which remains the sole producer of 11-aminoudecanoic acid today.
The chemical process of creating Nylon 11 begins with ricinoleic acid which makes up 85-90% of castor oil. Ricinoleic acid is first transesterified with methanol creating methyl ricinoleate, which is then cracked to create heptaldehyde and methyl undecylenate. These undergo hydrolysis to create methanol, which is re-used in the initial transesterification of ricinoleic acid, and undecylenic acid that is added on to hydrogen bromide. After hydrolysis, hydrogen bromide then undergoes nucleophilic substitution with ammonia to form 11-aminoudecanoic acid, which is polymerized into nylon 11.
Properties of Nylon
As seen in the table below, Nylon 11 has lower values of density, flexural and Young’s modulus, water absorption, as well as melting and glass transition temperatures. Nylon 11 is seen to have increased dimensional stability in the presence of moisture due to its low concentration of amides. Nylon 11 experiences 0.2-0.5% length variation and 1.9% weight variation after 25 weeks of submersion in water in comparison to 2.2-2.7% elongation variation and 9.5% weight variation for Nylon 6.
Due to its low water absorption, increased dimensional stability when exposed to moisture, heat and chemical resistance, flexibility, and burst strength, nylon 11 is used in various applications for tubing. In the fields of automotive, aerospace, pneumatics, medical, and oil and gas, nylon 11 is used in fuel lines, hydraulic hoses, air lines, umbilical hoses, catheters, and beverage tubing.
Nylon 11 is used in cable and wire sheathing as well as electrical housings, connectors and clips.
Nylon 11 is used in metal coatings for noise reduction and protection against UV exposure as well as resistance to chemicals, abrasion, and corrosion.
Nylon 11 is used in textiles through brush bristles, lingerie, filters, as well as woven and technical fabrics.
Nylon 11 is used in the soles and other mechanical parts of footwear. It is also seen in racket sports for racket strings, eyelets, and badminton shuttlecocks. Nylon 11 is used for the top layering of skis.