Plastics Information
10/13 Q&A: SPG Group is offering antistatic type of APET film for electronic or ESD sensitive packaging purpose. SPG Group APET is fully compatible with Eastman Chemical EastaStat PETG line, but with economic costs. SPG Group APET antistatic film's surface resistiviey is 109 to 1010 that is considering one of the best packaging material for your hard disk drive component packaging or one-way electronic packaging of computer/electronic parts. And the best of all, APET is considering an "Environmental-Safe" material.
10/4/99 Q&A: SPG Group bottle grade resins are the top-grade polythylene terephthalate (PET) thermoplastic resins primarily used in beverage (soft drinks and water), food and pharmaceutical packaging. These materials give the finished package the clarity, light weight, and impact resistance consumers demand. Manufacturers find SPG Group PET resin easy to mold, and allows them to obtain exotic shapes for package styling and ultimately shelf appeal. Above is a sample of produce package.
source: DuPont Packaging
09/27 Q&A: Above is a sample of produce package. The top layer is called OPP or BOPP-Biaxially Oriented Poly Propolyn. OPP is widely used in packaging industry especially in food and medical containers. BOPP is also the base film for industrial packaging tape. Due to its production character, the tear-strength is very strong. Elvax® EVA ethylene vinyl acetate copolymer resins are available from DuPont in a wide range of packaging film and coating grades. Elvax® combines tough, low-temperature sealability with excellent clarity, cling, flexibility, impact and puncture resistance. Its easy processability at low temperatures results in energy savings and trouble-free processing.
source: DuPont Packaging
09/10/99 Q&A: Generally speaking, drying PET or APET resins (see graph above) before processing is critical, why? PET or APET resin are hygroscopic that is they pick up moisture from the air easily. Because of this fact, an in-line desiccant hopper dryer is recommended to process PET or APET resin. A desiccant hopper dryer is a dryer where desiccant dried air is passed over the resin. The dry air absorbs and removes the excess water, leaving dry resin. Moisture that is not removed prior to extrusion reacts with the polyester to break down the molecular weight, causing a decrease in viscosity and melt strength, and a decrease in properties. Unfortunately, the effects of the moisture are invisible in the sheet so the physical properties can be affected even when the problem
source: DuPont Packaging
8/27 Q&A: Above is a snack bar packaging structure sample, it is a four layers structure with Surlyn film at the bottom with paper, LDPE and foil above it. Why Surlyn? Why "foil"? Why not "metalized PET"?
Surlyn(R)
is the DuPont name for its family of ionomer resins. SurlynSurlyn(R)
resins are available for use in conventional extrusion/coextrusion blown film, cast film,
and extrusion coating equipment designed to process polyethylene resins.* SurlynSurlyn(R) ionomer resins have a combination of properties
that are unique among polymers. They are made from ethylene acid copolymers, in which the
acid groups are partially neutralized with either zinc or sodium ions. The acid in the
polymer gives polarity and reduces crystallinity. The ionic bonding between the polymer
chains gives outstanding melt strength, toughness, and clarity.
source: DuPont Packaging
08/15 Q&A: Above is a liquid packaging structure sample, it is a three layers structure sandwich with Elvax and metalized PET in the middle. Why Elvax? Why "Metalized PET"? Why PET? Why not other plastics? Elvax® is the DuPont registered trademark for its ethylene-vinyl acetate (EVA) copolymer resins. In the packaging industry, typical processing applications for Elvax® include blown film, extrusion coated film, cast film, coextruded film, and blends with other resins. The Elvax® grades in this guide are sorted by vinyl acetate content. The vinyl acetate units in the copolymer modify the basic polyethylene structure and its properties. The addition of vinyl acetate units in the polyethylene provides these advantages: lower sealing temperature, increased flexibility, improved optical properties, greater adhesion, and increased impact and puncture resistance.
source: DuPont Packaging
8/7/99 Question: From the picture above (e.g. a
typical noodle cup packaging structure), the noodle cup itself is made of PS (Poly
Styrene) foam or commonly called styrofoam. But, the lid itself has more complicated
structure due to various reasons such as humidity-, pollution-, insect prevention and
shipping protection. For printing purpose (e.g. logo), the top-layer of lid is made of
paper. The layer LDPE is to block humidity. The foil layer is to prevent insect intrusion.
Then, what is "PRIMER" for? What is "Appeal"?
8/4/99 Q&A: More on PVC ?
PVC is made of by 56% Chlorine and 44% Ethylene combination. In the manufacturing of vinyl chloride monomer (VCM), ethylene and chlorine are first combined to made ethylene dichloride (EDC). Because EDC is a liquid at normal room temperature and pressure, it can easily be transported around the world for use in VCM plants. VCM is processed into PVC using a variety of closed-process methods that result in a freee-flowing powder or vinyl resin with a consistency between sugar and flour.
08/01/99 Question: What is #3 "V" stands for as above? The "V" stands for "Vinyl" and more closely it is PVC (Polyvinyl Chloride) or PVDC (Polyvinylidene Chloride). The vast majority of PVC is used in construction application, such as PVC pipe and vinyl siding. Only 7% or less of PVC sales is in the area of packaging, and PVC represent less than 5% of all plastic packaging application. PVDC is almost exclusively used in food and medical packaging application where PVC and other plastic films provide insufficient moisture, gas, and flavor barrier properties.
07/23/99 Question: What names of polymers can be drawn into fibers? A polymeric fiber is a polymer whose chains are stretched out straight (or close to straight) and lined up next to each other, all along the same axis. Polymers arranged in fibers like this can be spun into threads and used as textiles including Polyethylene, Polypropylene, Nylon, Polyester, Kevlar/Nomex, Polyacrylonitrile, Cellulose and Polyurethanes. It is important to point out that fibers are always made of polymers which are arranged into crystals.
07/05/99 Question: What is Mylar? Mylar is a polyester film made by Du Pont. The balloons are made of a sandwich, composed of Mylar and aluminum foil. Materials like this, make of two kinds of material, care called composites. However, the water balloons is made of natural rubber which is also one of the most popular natural material in our world.
