Milk bottle resin

Blow-molded bottles using LDPE were partly responsible for the rapid growth of polyethylene in the late 1940s and 1950s. However, with the introduction of high-density polyethylene in the late 1950s, a high stiffiiess resin suitable for the plastic milk bottle was introduced. 

Injection molding is unique compared to the other fabrication techniques used in the polyethylene industry because of the relatively low molecular 

Market Billion Pounds Annually Percent Market Share 

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Other properties that are important to the product or process include stress crack resistance, melt flow, and stiffness. Milk bottle resin has less stress crack resistance, higher flow, and slightly higher stiffness. If these properties would adversely affect the product/process, you should specify that you do not want significant quanities of milk bottle resin in the recycled resin. Other HDPE bottles are made from a lower density resin that has higher stress crack resistance and lower melt flow. 

Melt Flow Ratio of the FI and MI values is a relative measure of the polymer MWD where MFR values between 80-120 indicate that the MWD is relatively broad. Melt Index, Flow Index, MFR and density are only approximate values for each application. The milk bottle resin is an ethylene homopolymer, while the other products contain a small amount of comonomer (1-butene or 1-hexene) which is used to reduce polymer crystallinity. 

Dairy Milk bottle resin, ethylene homopolymer... 

The HDPE prepared with the Cr-based Phillips catalyst is the primary resin used in blow molding to manufacture various types of bottles. The two primary HDPE bottle applications are the milk bottle resin and the household industrial chemical (HIC) resin, with typical resin specifications summarized in Table 6.12. 

On occasion a potential market for plastics has been clearly defined and continually tantalizes resin suppliers by always remaining just out of reach. Such was the case with the dairy industry and the plastic milk bottle. 

Since the early 1960 s many of the largest resin suppliers have seen the huge potential volume to be gained by the replacement of the glass milk bottle with one made from a lightweight plastic. Several invested heavily in dairies and dairy equipment manufacturing without gaining acceptance by either the consumers or the dairy market. 

Celanese enjoys the major share of the merchant plastic milk bottles business in the United States because of this engineered high-density polyethylene resin. 

Wood fiber - recycled plastic composite lumber is a relatively new development and is similar to PS addition to plastic lumber because the potential exists for improved mechanical properties and dimensional stabilities. Wood fiber addition can serve as an excellent reinforcement for plastics, and wood fibers are abundant, lightweight, nonabrasive, nonhazardous and inexpensive. An effort is being made to examine the incorporation of treated and untreated aspen fibers into recycled HDPE milk bottles [Yam et al., 1990]. The work has shown tensile strength and Izod impact strength below that of HDPE alone when aspen fiber is added. Tensile modulus and flexural modulus are increased significantly above HDPE alone with the addition of wood fiber. Dispersion of the fiber in the resin has been reported as a dominating factor in the process thus far. 

For illustrative purposes, to demonstrate the state of polyolefin recycling in 1992, the life of 200 kg of virgin HOPE bottle resin is studied. The assumptions are that 10% of the resin is used in milk bottles, which is a homopolymer product, 8% is used in motor oil bottles, a difficult to clean product, and the remainder is used in other consumer bottles. A macroscopic perspective suggests that consumer products use about 5% post consumer recycled material and motor oil bottles about 25%. Some products would use more and some none at all. This does not take post industrial or internal scrap levels into consideration in terms of reclaimed content. It can be concluded that, at the current levels of recycling, a large fraction of the polyolefin molecules will be exposed to at most 4 thermal and shearing cycles. 

Blow-molded products represent the biggest use of HDPE resins, around 40%. Packaging applications account for by far the greatest share of this market. These include such products as bottles (especially for milk, juice, and soap), housewares, toys, pails, drums, and tanks. 

Many grades of polyethylene are used in food packaging, e.g., blow molded bottles for milk and blown film for wrapping meat and poultry. In the EU, the USA and other developed countries, the resin must satisfy governmental regulations for food contact. In the USA, the resin (including additives see Chapter 8)... 

The ultramarines range in color from a medium shade blue through violet to pink. A household example of an ultramarine blue in full shade is the Milk of Magnesia bottle. Standard grades of ultramarine pigments (uncoated) react with polyacetal resins, and I have observed color drift of these pigments in PC and PA 6/6. Some properties of ultramarine pigments are listed in Table 1. 

Sample preparation Prepare a column as follows. Swirl Chelating Sepharose Fast Flow resin (Pharmacia) in its bottle, add it to a polypropylene column to give a bed volume of 1.0-1.2 mL, wash 3 times with 2 mL portions of water, wash with 2 mL 10 mM copper sulfate, wash with two 2 mL portions of water. Centrifiige 5 mL milk at 10° at 1500 g for 15 min, remove the lower layer and add it to 10 mL succinate buffer, mix, centrifuge at 1500 g for 30 min, add the supernatant to the column. Wash with 2 mL succinate buffer, wash with 2 mL water, wash with 2 mL MeOH, wash with 2 mL water, wash with 700 pL citrate/phosphate buffer (be careful not to disturb bed), elute with 2.5 mL cit-rate/phosphate buffer (column is white and eluate is blue). Filter (Amicon Centricon 30,... 

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