we want to produce bottle from pp ,could u please any body say which grade pp is the best for stretch blow molding.
hi all , i would like to get into the bottle water industry , i have a great design for a bottle but not to sure where to get it made. i would love to use a biodegradable product, like PLA. also where i can fill my product with natural spring water and so on . if anyone has any info i would much appreciate it THANX, JEFF.
PLA Injection molding
Feed throat, oF (oC).. 70 (20)
Feed Section, oF (oC)..355 (180)
Compression Section, oF (oC)..410 (210)
Metering Section, oF (oC)..415 (213)
Hot Runner, oF (oC)..420 (216)
Nozzle Tips, oF (oC)..425 (218)
Mold, oF (oC)..77 (25)
Screw Speed, RPM..50-100
Back Pressure, PSI..150-200
Mold Shrinkage, in/in..0.004 +/- 0.001
Hope this information may help!!!!
PLA Resin Density: 1.25g/cm3;
Melting temperature: 145~155°C;
Glass transition temperature: 55~58°C;
Crystaliztion temperature: 95~120°C;
Drying temperature: 90~100°C;
Barrel temperature: 180°C for feeding zone, 210~220°C for other zones;
Preform mold: Valve gate system compatiable, but make sure hot runner system can run with material leakage at temperature 220°C.
Mold temperature: no less than 25°C to avoid acid generation. Post cooling suggested to reduce cycle time.
In one word, existing PET preform injection system is compatiable with PLA preform injection.
Tell in details about formation of preform from PLA . Is it required that dehumidifying drying condition which required for PET. What is the melting temp. for PLA?
But we don't have idea on how to blow it into bottles.
But just for information:
As bottled water sales climb dramatically worldwide, the amount of discarded PET bottles dumped into the environment is staggering. Add to the environmental issues the current economical and political aspects involved with petroleumbased products and you have a host of good reasons why packagers are looking for alternative materials.
No wonder the bottled water industry is looking at PLA! It’s a natural solution in an industry committed to its consumers’ health and well-being.
PLA is a biodegradable thermoplastic derived from lactic acid. Lactic acid can be obtained on the basis of renewable starch containing resources (e.g. corn, wheat or sugar beat) by fermentation, or by chemical synthesis of non-renewable resources.
It resembles clear polystyrene, provides good aesthetics (gloss and clarity), but it is stiff and brittle and needs modifications for most practical applications (i.e. plasticizers increase its flexibility).
It can be processed like most thermoplastics into fibres, films, thermoformed or injection moulded. Used for compost bags, plant pots, diapers and packaging.
If composted properly it takes 3-4 weeks for complete degradation. The first stage of degradation (two weeks) is a hydrolisis to water soluble oligomers and lactic acid. The latter, as a naturally occurring substance, is a rapid metabolisation into CO2, water and biomass by a variety of micro-organisms.
There is little difference between PLA and PET bottles in terms of appearance and performance. In most cases, what you can do with PET, you can do with PLA, including shape, size, color and other design features. Customers will not know the bottle is made of PLA unless you tell them. The difference is found in material characteristics. Hence, the requirement for PLA-specific blow molders, which must address special issues. Traditional PET blow molders cannot handle PLA successfully.
The primary issue is one of material temperature, which includes both preheating of the preforms before entering the stretch-molding process and subsequent cooling down of blown bottles.
PLA preforms must be heated to 75°C (167°F) before entering the stretchmolding process, as opposed to 100°C for PET. At the higher temperature, PLA starts to shrink, so the typical PET blow molder is problematic with PLA.
While PLA preforms heat up easily, the material is difficult to cool down; bottle deformation results when they are not adequately cooled before they exit the molds. Therefore, the freshly blown bottles must be cooled down quickly before they leave their molds. Consequently, special cooling techniques must be designed and built into each mold.
Additionally, precision process controls over all heating lamps and blowing sequences is a must. Fluctuation of a degree or two either way leads to finished bottle quality issues. PLA’s temperature sensitivity also requires enhanced airflow to ensure even heating in the heat tunnels. When multiple heat tunnels are involved, as is generally the case in blow molders, it is critical to precisely compensate for potentially different heat lamps and airflow so that bottles from each tunnel are consistently heated for optimal performance in the molds. This ensures a consistently high-quality finished bottle.
Precision controls over air pressure and flows are equally critical. This technology helps move PLA material down from the preform’s neck area to the bottom to make sure desired thickness is achieved in the bottle from bottom to top.
annyone have anny info on this?