Aishwarya Industries Tilak Nagar, kanpur, Uttar Pradesh

Polyvinyl chloride, (IUPAC Poly(chloroethanediyl)) commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups (ethenyls) having one of their hydrogens replaced with a chloride group.Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene.PVC is widely used in construction because it is cheap, durable, and easy to assemble. PVC production is expected to exceed 40 million tons by 2016.It can be made softer and more flexible by the addition of plasticizers, the most widely used being phthalates. In this form, it is used in clothing and upholstery, and to make flexible hoses and tubing, flooring, to roofing membranes, and electrical cable insulation. It is also commonly used in figurines and in inflatable products such as waterbeds, pool toys, and inflatable structures. PreparationPolyvinyl chloride is produced by polymerization of the vinyl chloride monomer (VCM), as shown.Since about 57% of its mass is chlorine, creating a given mass of PVC requires less petroleum than many other polymers.[citation needed] However, because PVC also has a much higher density than hydrocarbon polymers, and chlorine production has its own energy requirements, this ends up being of little practical relevance in the production of most solid objects.By far the most widely used production process is suspension polymerization. In this process, VCM and water are introduced into the polymerization reactor and a polymerization initiator, along with other chemical additives, are added to initiate the polymerization reaction. The contents of the reaction vessel are continually mixed to maintain the suspension and ensure a uniform particle size of the PVC resin. The reaction is exothermic, and thus requires a cooling mechanism to maintain the reactor contents at the appropriate temperature. As the volumes also contract during the reaction (PVC is denser than VCM), water is continually added to the mixture to maintain the suspension.Once the reaction has run its course, the resulting PVC slurry is degassed and stripped to remove excess VCM (which is recycled into the next batch) then passed though a centrifuge to remove most of the excess water. The slurry is then dried further in a hot air bed and the resulting powder sieved before storage or pelletization. In normal operations, the resulting PVC has a VCM content of less than 1 part per million.Other production processes, such as micro-suspension polymerization and emulsion polymerization, produce PVC with smaller particle sizes (10 μm vs. 120-150 μm for suspension PVC) with slightly different properties and with somewhat different sets of applications.The product of the polymerization process is unmodified PVC. Before PVC can be made into finished products, it almost always requires conversion into a compound by the incorporation of additives such as heat stabilizers, UV stabilizers, lubricants, plasticizers, processing aids, impact modifiers, thermal modifiers, fillers, flame retardants, biocides, blowing agents and smoke suppressors, and, optionally pigments.[5]PropertiesThe properties for PVC are usually categorized based on rigid and flexible PVCs.Property Rigid PVC Flexible PVCDensity [g/cm3][6] 1.3–1.45 1.1–1.35Thermal conductivity [W/(m·K)][7] 0.14–0.28 0.14–0.17Yield strength [MPa][6] 31–60 10–25Young's modulus [psi] 490,000[8] Flexural strength (yield) [psi] 10,500[8] Compression strength [psi] 9500[8] Coefficient of thermal expansion (linear) [mm/(mm °C)] 5×10−5[8] Vicat B [°C][7] 65–100 Not recommendedResistivity [Ω m][9][10] 1016 1012–1015Surface resistivity [Ω][9][10] 1013–1014 1011–1012HistoryPVC was accidentally discovered at least twice in the 19th century, first in 1835 by Henri Victor Regnault and in 1872 by Eugen Baumann. On both occasions the polymer appeared as a white solid inside flasks of vinyl chloride that had been left exposed to sunlight. In the early 20th century the Russian chemist Ivan Ostromislensky and Fritz Klatte of the German chemical company Griesheim-Elektron both attempted to use PVC (polyvinyl chloride) in commercial products, but difficulties in processing the rigid, sometimes brittle polymer blocked their efforts. Waldo Semon and the B.F. Goodrich Company developed a method in 1926 to plasticize PVC by blending it with various additives. The result was a more flexible and more easily processed material that soon achieved widespread commercial use.ApplicationsPVC's intrinsic properties make it suitable for a wide variety of applications. It is biologically and chemically resistant, making it the plastic of choice for most household sewerage pipes and other pipe applications where corrosion would limit the use of metal.With the addition of impact modifiers and stabilizers, it becomes a popular material for window and door frames. By adding plasticizers, it can become flexible enough to be used in cabling applications as a wire insulator. It is also used to make vinyl records.ClothingPVC has become widely used in clothing, to either create a leather-like material or at times simply for the effect of PVC. PVC clothing is common in Goth, Punk and alternative fashions. PVC is cheaper than rubber, leather, and latex and so it is more widely available and worn.

Polypropylene (PP), also known as polypropene, is a thermoplastic polymer, made by the chemical industry and used in a wide variety of applications, including packaging, textiles (e.g. ropes, thermal underwear and carpets), stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes. An addition polymer made from the monomer propylene, it is rugged and unusually resistant to many chemical solvents, bases and acids.In 2007, the global market for polypropylene had a volume of 45.1 million tons, which led to a turnover of about 65 billion US-dollars (47.4 billion Euro).Most commercial polypropylene is isotactic and has an intermediate level of crystallinity between that of low-density polyethylene (LDPE) and high-density polyethylene (HDPE). Polypropylene is normally tough and flexible, especially when copolymerized with ethylene. This allows polypropylene to be used as an engineering plastic, competing with materials such as ABS. Polypropylene is reasonably economical, and can be made translucent when uncolored but is not as readily made transparent as polystyrene, acrylic, or certain other plastics. It is often opaque or colored using pigments. Polypropylene has good resistance to fatigue.The melting of polypropylene occurs as a range, so a melting point is determined by finding the highest temperature of a differential scanning calorimetry chart. Perfectly isotactic PP has a melting point of 171 °C (340 °F). Commercial isotactic PP has a melting point that ranges from 160 to 166 °C (320 to 331 °F), depending on atactic material and crystallinity. Syndiotactic PP with a crystallinity of 30% has a melting point of 130 °C (266 °F).[2]The melt flow rate (MFR) or melt flow index (MFI) is a measure of molecular weight of polypropylene. The measure helps to determine how easily the molten raw material will flow during processing. Polypropylene with higher MFR will fill the plastic mold more easily during the injection or blow-molding production process. As the melt flow increases, however, some physical properties, like impact strength, will decrease.There are three general types of polypropylene: homopolymer, random copolymer, and block copolymer. The comonomer used is typically ethylene. Ethylene-propylene rubber or EPDM added to polypropylene homopolymer increases its low temperature impact strength. Randomly polymerized ethylene monomer added to polypropylene homopolymer decreases the polymer crystallinity and makes the polymer more transparent.DegradationPolypropylene is liable to chain degradation from exposure to heat and UV radiation such as that present in sunlight. Oxidation usually occurs at the tertiary carbon atom present in every repeat unit. A free radical is formed here, and then reacts further with oxygen, followed by chain scission to yield aldehydes and carboxylic acids. In external applications, it shows up as a network of fine cracks and crazes that become deeper and more severe with time of exposure.For external applications, UV-absorbing additives must be used. Carbon black also provides some protection from UV attack. The polymer can also be oxidized at high temperatures, a common problem during molding operations. Anti-oxidants are normally added to prevent polymer degradation.HistoryPropylene was first polymerized to a crystalline isotactic polymer by Giulio Natta and his coworkers in March 1954.This pioneering discovery led to large-scale commercial production of isotactic polypropylene from 1957 onwards.Syndiotactic polypropylene was also first synthesized by Giulio Natta and his coworkers.An important concept in understanding the link between the structure of polypropylene and its properties is tacticity. The relative orientation of each methyl group (CH3 in the figure) relative to the methyl groups in neighboring monomer units has a strong effect on the polymer's ability to form crystals.A Ziegler-Natta catalyst is able to restrict linking of monomer molecules to a specific regular orientation, either isotactic, when all methyl groups are positioned at the same side with respect to the backbone of the polymer chain, or syndiotactic, when the positions of the methyl groups alternate. Commercially available isotactic polypropylene is made with two types of Ziegler-Natta catalysts. The first group of the catalysts encompases solid (mostly supported) catalysts and certain types of soluble metallocene catalysts. Such isotactic macromolecules coil into a helical shape; these helices then line up next to one another to form the crystals that give commercial isotactic polypropylene many of its desirable properties.Another type of metallocene catalysts produce syndiotactic polypropylene. These macromolecules also coil into helices (of a different type) and form crystalline materials.When the methyl groups in a polypropylene chain exhibit no preferred orientation, the polymers are called atactic. Atactic polypropylene is an amorphous rubbery material. It can be produced commercially either with a special type of supported Ziegler-Natta catalyst or with some metallocene catalysts.Modern supported Ziegler-Natta catalysts developed for the polymerization of propylene and other 1-alkenes to isotactic polymers usually use TiCl4 as an active ingredient and MgCl2 as a support.,The catalysts also contain organic modifiers, either aromatic acid esters and diesters or ethers. These catalysts are activated with special cocatalysts containing an organoaluminum compound such as Al(C2H5)3 and the second type of a modifier. The catalysts are differentiated depending on the procedure used for fashioning catalyst particles from MgCl2 and depending on the type of organic modifiers employed during catalyst preparation and use in polymerization reactions. Two most important technological characteristics of all the supported catalysts are high productivity and a high fraction of the crystalline isotactic polymer they produce at 70-80°C under standard polymerization conditions. Commercial synthesis of isotactic polypropylene is usually carried out either in the medium of liquid propylene or in gas-phase reactors.Commercial synthesis of syndiotactic polypropylene is carried out with the use of a special class of metallocene catalysts. They employ bridged bis-metallocene complexes of the type bridge-(Cp1)(Cp2)ZrCl2 where the first Cp ligand is the cyclopentadienyl group, the second Cp ligand is the fluorenyl group, and the bridge between the two Cp ligands is -CH2-CH2-, >SiMe2, or >SiPh2.[8] These complexes are converted to polymerization catalysts by activating them with a special organoaluminum cocatalyst, methylalumoxane MAOManufacturingMelt processing of polypropylene can be achieved via extrusion and molding. Common extrusion methods include production of melt-blown and spun-bond fibers to form long rolls for future conversion into a wide range of useful products, such as face masks, filters, nappies (diapers) and wipes.The most common shaping technique is injection molding, which is used for parts such as cups, cutlery, vials, caps, containers, housewares, and automotive parts such as batteries. The related techniques of blow molding and injection-stretch blow molding are also used, which involve both extrusion and molding.The large number of end-use applications for polypropylene are often possible because of the ability to tailor grades with specific molecular properties and additives during its manufacture. For example, antistatic additives can be added to help polypropylene surfaces resist dust and dirt. Many physical finishing techniques can also be used on polypropylene, such as machining. Surface treatments can be applied to polypropylene parts in order to promote adhesion of printing ink and paints.ApplicationsSince polypropylene is resistant to fatigue, most plastic living hinges, such as those on flip-top bottles, are made from this material. However, it is important to ensure that chain molecules are oriented across the hinge to maximize strength.Very thin sheets of polypropylene are used as a dielectric within certain high-performance pulse and low-loss RF capacitors.High-purity piping systems are built using polypropylene. Stronger, more rigid piping systems, intended for use in potable plumbing, hydronic heating and cooling, and reclaimed water applications, are also manufactured using polypropylene.[10] This material is often chosen for its resistance to corrosion and chemical leaching, its resilience against most forms of physical damage, including impact and freezing, its environmental benefits, and its ability to be joined by heat fusion rather than gluing.Many plastic items for medical or laboratory use can be made from polypropylene because it can withstand the heat in an autoclave. Its heat resistance also enables it to be used as the manufacturing material of consumer-grade kettles. Food containers made from it will not melt in the dishwasher, and do not melt during industrial hot filling processes. For this reason, most plastic tubs for dairy products are polypropylene sealed with aluminum foil (both heat-resistant materials). After the product has cooled, the tubs are often given lids made of a less heat-resistant material, such as LDPE or polystyrene. Such containers provide a good hands-on example of the difference in modulus, since the rubbery (softer, more flexible) feeling of LDPE with respect to polypropylene of the same thickness is readily apparent. Rugged, translucent, reusable plastic containers made in a wide variety of shapes and sizes for consumers from various companies such as Rubbermaid and Sterilite are commonly made of polypropylene, although the lids are often made of somewhat more flexible LDPE so they can snap on to the container to close it. Polypropylene can also be made into disposable bottles to contain liquid, powdered, or similar consumer products, although HDPE and polyethylene terephthalate are commonly also used to make bottles. Plastic pails, car batteries, wastebaskets, cooler containers, dishes and pitchers are often made of polypropylene or HDPE, both of which commonly have rather similar appearance, feel, and properties at ambient temperature.A common application for polypropylene is as biaxially oriented polypropylene (BOPP). These BOPP sheets are used to make a wide variety of materials including clear bags. When polypropylene is biaxially oriented, it becomes crystal clear and serves as an excellent packaging material for artistic and retail products.Polypropylene, highly colorfast, is widely used in manufacturing carpets, rugs and mats to be used at home.Polypropylene is widely used in ropes, distinctive because they are light enough to float in water.For equal mass and construction, polypropylene rope is similar in strength to polyester rope. Polypropylene costs less than most other synthetic fibers.Polypropylene is also used as an alternative to polyvinyl chloride (PVC) as insulation for electrical cables for LSZH cable in low-ventilation environments, primarily tunnels. This is because it emits less smoke and no toxic halogens, which may lead to production of acid in high-temperature conditions.Polypropylene is also used in particular roofing membranes as the waterproofing top layer of single-ply systems as opposed to modified-bit systems.

Polyethylene terephthalate (sometimes written poly(ethylene terephthalate)), commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination with glass fiber.Depending on its processing and thermal history, polyethylene terephthalate may exist both as an amorphous (transparent) and as a semi-crystalline polymer. The semicrystalline material might appear transparent (particle size < 500 nm) or opaque and white (particle size up to a few microns) depending on its crystal structure and particle size. Its monomer (bis-β-hydroxyterephthalate) can be synthesized by the esterification reaction between terephthalic acid and ethylene glycol with water as a byproduct, or by transesterification reaction between ethylene glycol and dimethyl terephthalate with methanol as a byproduct. Polymerization is through a polycondensation reaction of the monomers (done immediately after esterification/transesterification) with ethylene glycol as the byproduct (the ethylene glycol is directly recycled in production).The majority of the world's PET production is for synthetic fibers (in excess of 60%) with bottle production accounting for around 30% of global demand. In discussing textile applications, PET is generally referred to as simply "polyester" while "PET" is used most often to refer to packaging applications. The polyester industry makes up about 18% of world polymer production and is third after polyethylene (PE) and polypropylene (PP).UsesSailcloth is typically made from PET fibers also known as polyester or under the brand name Dacron; colorful lightweight spinnakers are usually made of nylon.PET can be semi-rigid to rigid, depending on its thickness, and it is very lightweight. It makes a good gas and fair moisture barrier, as well as a good barrier to alcohol (requires additional "barrier" treatment) and solvents. It is strong and impact-resistant. It is naturally colorless with a high transparency.Plastic bottles made from PET are excellent barrier materials and are widely used for soft drinks (see carbonation). For certain specialty bottles, PET sandwiches an additional polyvinyl alcohol to further reduce its oxygen permeability.Biaxially oriented PET film (often known by one of its trade names, "Mylar") can be aluminized by evaporating a thin film of metal onto it to reduce its permeability, and to make it reflective and opaque (MPET). These properties are useful in many applications, including flexible food packaging and thermal insulation, such as "space blankets". Because of its high mechanical strength, PET film is often used in tape applications, such as the carrier for magnetic tape or backing for pressure sensitive adhesive tapes.Non-oriented PET sheet can be thermoformed to make packaging trays and blisters. If crystallizable PET is used, the trays can be used for frozen dinners, since they withstand both freezing and oven baking temperatures.When filled with glass particles or fibers, it becomes significantly stiffer and more durable. This glass-filled plastic, in a semi-crystalline formulation, is sold under the tradename Rynite, Arnite, Hostadur, and Crastin.While most thermoplastics can, in principle, be recycled, PET bottle recycling is more practical than many other plastic applications. The primary reason is that plastic carbonated soft drink bottles and water bottles are almost exclusively PET. PET has a resin identification code of 1. One of the uses for a recycled PET bottle is for the manufacture of polar fleece material. Among its many uses, companies such as English Retreads use the PET material to line their products. It can also make fiber for polyester products.Because of the recyclability of PET and the relative abundance of post-consumer waste in the form of bottles, PET is rapidly gaining market share as a carpet fiber. Mohawk Industries released everSTRAND in 1999, a 100% post-consumer recycled content PET fiber. Since that time, more than 17 billion bottles have been recycled into carpet fiber.[4] Pharr Yarns, a supplier to numerous carpet manufacturers including Looptex, Dobbs Mills, and Berkshire Flooring,produces a BCF (bulk continuous filament) PET carpet fiber containing a minimum of 25% post-consumer recycled content.PET, as with many plastics, is also an excellent candidate for thermal disposal (incineration), as it is composed of carbon, hydrogen, and oxygen, with only trace amounts of catalyst elements (but no sulfur). PET has the energy content of soft coal.PET was patented in 1941 by the Calico Printers' Association of Manchester. The PET bottle was patented in 1973 by Nathaniel Wyeth.One of the most important characteristics of PET is referred to as intrinsic viscosity (IV)The intrinsic viscosity of the material, measured in deciliters per gram (dℓ/g) is dependent upon the length of its polymer chains. The longer the polymer chains, the more entanglements between chains and therefore the higher the viscosity. The average chain length of a particular batch of resin can be controlled during polycondensation.The intrinsic viscosity range of PETFiber grade0.40 – 0.70 dℓ/g Textile0.72 – 0.98 dℓ/g Technical, tire cordFilm grade0.60 – 0.70 dℓ/g BoPET (biaxially oriented PET film)0.70 – 1.00 dℓ/g Sheet grade for thermoformingBottle grade0.70 – 0.78 dℓ/g Water bottles (flat)0.78 – 0.85 dℓ/g Carbonated soft drink gradeMonofilament1.00 – 2.00 dℓ/g[edit]Drying

Low-density polyethylene (LDPE) is a thermoplastic made from petroleum. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its manufacture employs the same method today. LDPE is commonly recycled[citation needed] and has the number "4" as its recycling symbol. Despite competition from more modern polymers, LDPE continues to be an important plastic grade. In 2009 the worldwide LDPE market reached a volume of 22.2 billion US-Dollars (15.9 billion Euro).PropertiesLDPE is defined by a density range of 0.910–0.940 g/cm³. It is not reactive at room temperatures, except by strong oxidizing agents, and some solvents cause swelling. It can withstand temperatures of 80 °C continuously and 95 °C for a short time. Made in translucent or opaque variations, it is quite flexible, and tough but breakable.[citation needed]LDPE has more branching (on about 2% of the carbon atoms) than HDPE, so its intermolecular forces (instantaneous-dipole induced-dipole attraction) are weaker, its tensile strength is lower, and its resilience is higher. Also, since its molecules are less tightly packed and less crystalline because of the side branches, its density is lower. LDPE contains the chemical elements carbon and hydrogen.Chemical resistance Excellent resistance (no attack) to dilute and concentrated acids, alcohols, bases and estersGood resistance (minor attack) to aldehydes, ketones and vegetable oilsLimited resistance (moderate attack suitable for short-term use only) to aliphatic and aromatic hydrocarbons, mineral oils, and oxidizing agentsPoor resistance, and not recommended for use with Halogenated hydrocarbons.ApplicationsLDPE is widely used for manufacturing various containers, dispensing bottles, wash bottles, tubing, plastic bags for computer components, and various molded laboratory equipment. Its most common use is in plastic bags. Other products made from it include:Trays and general purpose containersFood storage and laboratory containersCorrosion-resistant work surfacesParts that need to be weldable and machinableParts that require flexibility, for which it serves very wellVery soft and pliable partsSix pack ringsJuice and milk cartons, whose "cardboard" is actually liquid packaging board, a laminate of paperboard and LDPE (as the water-proof inner and outer layer), and often with of a layer of aluminum foil (thus becoming aseptic packaging).Parts of computer hardware, such as hard disk drives, screen cards, and optical disc drivesPlayground slidesPlastic wraps

Bottle caps, or closures, are used to seal the openings of bottles of many types. They can be small circular pieces of metal, usually steel, with plastic backings, and for plastic bottles a plastic cap is used instead. A bottle cap is typically colorfully decorated with the logo of the brand of beverage. Caps can also be plastic, sometimes with a pour spout. Flip-Top caps like Flapper closures provide controlled dispensing of dry products. Bottle caps are often made of a different type of plastic than the bottle itself, and are often recyclable.Bottle caps were originally designed to be pressed over and around the top of a glass bottle to grab a small flange on the bottleneck. The Crown Cork was patented by William Painter on 2 February 1892 (U.S. Patent 468,258). It originally had 24 teeth and a cork seal with a paper backing to prevent contact between the contents and the metal cap. The current version has 21 teeth. To open these bottles, a bottle opener is generally advised, although some bottles incorporate a screw cap, eliminating the need for the opener.Individuals have experimented with different ways of opening bottles, including using teeth or snapping them open across another surface. A separate interest to collecting bottle caps is that of interesting ways to open bottles.The height of the crown cap was reduced and specified in the German standard DIN 6099 in the 1960s. This also defined the "twist-off" crown cap, now widely used in the United States, Canada, and Australia. This bottle cap is pressed around screw threads instead of a flange. Such a bottle cap can be taken off merely by twisting the cap.Bottle caps are also a way for bottlers to hold promotions, especially for soda companies. A message is printed on the inside of the cap and people with the right message may win a prize. Since the bottle must be purchased to determine the message and win, people usually purchase more of the drink to increase their chances of winning. The most common prize is a free soda from that company.Some companies, such as Snapple, also print interesting facts on the inside of their caps. Mickey's Malt Liquor as well, prints riddles underneath the 24 and 40 oz. bottle caps. Usually this is done on wide-mouthed bottles that have large caps with enough printing area to put a short sentence. Purpose of closuresMany containers and packages require a means of closing. It can be a separate device or seal or sometimes a integral latch or lock. Depending on the contents and container, closures have several functions:Keep the container closed and the contents contained for the specified shelf life until time of openingProvide a barrier to dirt, oxygen, moisture, etc. Control of permeation is critical to many types of products: foods, chemicals, etc.Keep the product secure from undesired premature openingProvide a means of reclosing or reusing the containerAssist in dispensing and use of productAllow reasonable ease to open the container by the intended user. Difficult to open containers may cause wrap rage. The force or torque required to open a closure is an important consideration for packaging engineers.Many types of packaging with their closures are regulated for strength, safety, security, communication, recycling, and environmental requirements.Types of closuresClosures need a means of attaching to the container with sufficient security. Threads, lugs, hinges, locks, adhesives, etc. are used.Many closures need to have the ability to adjust to slight manufacturing variation in the container and the closure structure. Some closures are made of flexible material such as cork, rubber, or plastic foam. Often an o-ring or a closure liner (gasket made of pulp or foam cap liner) is used. Linerless closures often use a deformable plastic rim or structure to maintain the seal.Secondary seals are common with sensitive products that may deteriorate or where extra security is needed. Foil or plastic innerseals are used on some bottles, Heat sealed lidding films are used on some tubs. External shrink bands, labels, and tapes are sometimes used outside the primary closure structure.Screw topA screw closure is a mechanical device which is screwed on and off of a threaded "finish" on a container. Either continuous threads (C-T) or lugs are used. Metal caps can be either preformed or in some instances, rolled on after application. Plastic caps may use several types of molded polymer.Some screw tops have multiple pieces. For example, a mason jar often has a lid with a built in rubbery seal and a separate threaded ring or band.Crown capsBeverage bottles are frequently closed with crown beverage caps. These are shallow metal caps that are crimped into locking position around the head of the bottle.Snap onSome closures snap on . For opening , the top is designed to pry off or , break off, or have a built in dispenser.  Friction fitSome containers have a loose lid for a closure. Laboratory glassware often has ground glass joints that allow the pieces to be fitted together easily.An Interference fit or friction fit requires some force to close and open, providing additional security. Paint cans often have a friction fit plug.DispensingA wide variety of convenience dispensing features can be built in to closures. Spray bottles and cans with aerosol spray have special closure requirements. Pour spouts, measuring attachments, sifting devices, etc. are common.HistoryEarly pottery and ceramic containers often had lids that fit reasonably snug onto the body of the container. The narrow necks of ancient amphora were closed with a plug of cork, wood, or ceramic and sealed with mortar.[3] Wooden Barrels often had bungholes closed by cork or wood bungs.Some early tinplate cans were made with threaded necks for screw top closures.Beverage bottles started using the Hutter Stopper in 1893. This involved a porcelain plug fitted with a rubber washer, which was then forced down into the lip of the bottle. This technique only works with carbonated beverages. The Hutter Stopper became standard in beer bottling in the late 1890s / early 1900s. Bail closures on bottles were invented by Henry William Putnam in 1859. These involved heavy wire bail attached to a bottle's neck that swung over the cork to hold it in.The world's first modern bottle cap, the crown cork, was invented by William Painter in 1890 in Baltimore. The screw cap using rust resistant aluminum was first used in prescription drug bottling in the 1920s.Molded urea based bottle caps were first introduced in the early 1900s.