Two piece syringes are made with Polypropylene barrel, either Homopolymer or Random Copolymer and plunger with built-in head, moulded out of High Density Polyethylene. Three piece syringes are made with both barrel and plunger of Polypropylene with a latex rubber bunge infront of plunger.
H110MA & R120 MK are the respective Homopolymer ad Random Copolymer grades used, the moulds generally being multi-cavity. Both the grades are approved as per U.S Pharmacopea XXIII. The grades and additives incorporated in them also comply with FDA. Relene M60075 is used for plunger of two piece syringes.
The syringes have to undergo theylene oxide, carbon dioxide mix or gamma sterilisation. The surface of the barrels are flame treated to make them conducive for printing.
Thin wall containers:
The containers have a wall thickness below 1.0 mm. High flow grades are used to mould multi- cavity containers. Controlled rheology grades help in getting warpage free mouldings. Random Copolymer gives good clarity and gloss. Polypropylene is used for hot fill applications, because of high melting point and HDT.
High Density Polyethylene is used to mould thin wall containers, used for frozen food applciations, because of its better impact strength at low temperature. Brittleness temperature measured for HDPE is - 73 deg, Cent.
Three types of toothbrushes are generally manufactured:
Low cost, where PPHP handles are used
Medium cost, where RCP handles are used.
High cost, where SAN handles are used.
A new development is the spring back brushes where the handles are made of PP Impact Copolymers or a combination of PP impact and Homopolymers.
The following grades are used:
H110 MA R120MK