Alpha Packaging, a manufacturer of plastic bottles and jars for the personal care, pharmaceutical and nutritional supplement industries, has recently introduced four 32-ounce narrow-neck bottles that are made using a two-stage blow molding process. Each of the new 32-oz. bottles represents the largest size in Alpha’s four most popular polyethylene terephthalate (PET) liquid lines: Boston Rounds, Cosmo Rounds, Modern Rounds and Capri Ovals.

These bottles are typically used for large quantities of hand sanitizers, liquid soaps, shampoos and conditioners, and other liquids used around the home or in larger institutional settings. The overflow for each bottle exceeds 1000ml (1 liter), so they are ideal for items marketed as either 32 liquid ounces or liter-size.

All four bottles are made from the same 50-gram 28-410 preforms on two-stage (reheat and blow) machinery at Alpha’s Salt Lake City plant. Reheat and blow is a stretch blow molding process in which a plastic preform is injection molded in one process, and then at a later time, that preform is fed into a machine, reheated, and stretch blow molded in a second step. Often, preforms are made by one company and purchased by another company to make the finished bottle. However, in the case of these 50-gram preforms, Alpha manufactures both the preform and the bottles in its two-stage process.

Alpha’s 50-gram preforms are available in standard colors of clear, light amber, cobalt blue and white for any of the four styles of narrow-neck bottles. Minimums for colored bottles are 50,000 pieces; clear bottles have a one-pallet minimum.

The two-stage process has several advantages over Alpha’s usual single-stage injection stretch blow molding process, especially for the larger bottles for which Alpha is using it. According to Bob Wilson, director of Alpha Technology Center, “The two-stage stretch blow molding process offers the ability to produce fairly lightweight containers with very high impact resistance, which is ideal for these large PET bottles.” The two-stage process also has some drawbacks, including visual imperfections and blemishes in some of the large PET bottles.

Samples of Alpha’s stock bottles, including all four of its new 32-oz. bottles, can be ordered by visiting www.alphap.com/products/catalog.html and searching under Alpha’s PET Narrow Neck bottles.