Milk cartons

Inks for polymer coated paper board are designed for printing on polyethylene coated SBS (solid bleached sulfate) paper board substrates used in milk cartons, ice cream cartons, beverage cups, and paper plates. 

A typical ink for coated board is composed of an epoxy ester based pigment dispersion, styrene acrylic emulsion vehicle, and an epoxy ester solution vehicle. The epoxy resin commonly used is an ester of drying or semi-drying fatty acid and acrylic acid (Sect 5.2.3). The system undergoes oxidation to give moisture and alkali resistance [11]. Alternative polymers that may be used in inks for coated board are aziri-dine (ethylene imine) crosslinking styrene acrylic or a VAE (vinyl acetate ethylene) self crosslinldng emulsion polymer. 

Milk carton ink must have resistance to alkaline detergent based chain lubricants. A fatty add acrylic epoxy ester [11] is the key resin used in this type of ink. Spedal pigment dispersions are used based on the same epoxy ester since conventional styrene acryhc based pigment dispersions are not stable in epoxy ester based systems. 

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The AKDs are used in paper sizing appHcations. Paper sizing chemicals provide paper and paperboard with resistance to wetting by Hquids, especially water repeUency in paper cups, milk cartons, photographic paper, coatings, and packaging paper (139) (see Paper Papermaking additives). 

Alkaline sizing agents are especially effective in milk-carton board and printing and writing grades that utilize calcium carbonate fillers. 

We use extrusion coating to apply thin layers of polymer to the surface of non-polymeric substrates such as cardboard or aluminum foil. Extrusion coated materials are extensively used in food packaging. Products include the coated cardboard used to make milk cartons and the coated aluminum foil used to seal dairy product tubs. The process of extrusion coating has much in common with film casting. 

The coating of polymer that we put on paperboard serves two purposes when we convert it into juice and milk cartons. It prevents the contents from leaking out and it acts as an adhesive so that we can heat-seal the coated paperboard to itself to form a container. Low density polyethylene is the polymer of choice for this application it has sufficient melt strength to... 

Touch your head you re touching a polymer— your hair Polymers are in plastic milk cartons, bicycle helmets, tires, playground balls, cotton, wood, tennis shoes, and your toothbrush. 

Some polymers are natural, like your hair. Many others, like the plastic milk carton, are synthetic, or manufactured. 

Poly(vinyl acetate) emulsions are used in bookbinding, milk cartons, envelopes, and automobile upholstery. 

Figure 1.25 Life-cycle flow diagram for milk cartons.

Ryan et al. (1992) analyzed the concentrations of CDDs/CDFs in Canadian bleached-paper milk containers from 1988 to 1989 and examined the resulting concentrations transferred to the milk. Milk-carton paper manufactured prior to 1989 tested positive for 2,3,7,8-TCDF and 2,3,7,8-TCDD, with levels on a TEQ basis varying between 1.4 and 55 ng/kg of paper. Bleached milk-carton paper produced after mid-1989 tested negative for these compounds at a limit of detection of 1 ng/kg paper. Storage of 3 types of milk in the pre-1989 low- and high-level cartons resulted in the transfer of the TCDD/TCDF into the milk, most of which occurred within the first 7 days. The TCDD/TCDF transfer varied between 3 and 25%, with whole and 2% fat milk accumulating about twice the concentrations of skim milk. On the basis of these results, milk stored for up to 14 days at 5 °C in currently produced bleached-paper containers with less than 1 ng TEQ/kg of paper would not contain any detectable CDDs/CDFs (<0.005 ng TEQ/kg milk). 

Rappe C, Lundstroem G, Glas B, et al. 1990. Levels of PCDDs and PCDFs in milk cartons in commercial milk. Chemosphere 20 1649-1656. 

To prepare, clean and dry a square, half-gallon milk carton. Pour in 4 cups of fuel and 2 tablespoons of denatured alcohol. Mix well. Add 2 1/2 cups of soap powder or 3 1/2 cups of soap flakes. Stir until it begins to thicken, approximately 15 minutes. Seal the carton with tape and let it sit for 2 days. The mixture will thicken into a firm buttery paste. Chill for an hour in the refrigerator, remove, and carefully peel off the milk carton. Cut the resulting block into 1-inch slabs and place them in individual sandwich bags. Double wrap to help contain the fumes. 

Other Paperboard Remaining paperboard products consist of familiar products such as board for packaging foodstuffs, shirt board, and tablet backs. Some paperboard is bleached for use in packaging food products. Milk carton stock is an example of the use of bleached board. 

Milk Carton/PE dioxins 4 Milk 1.0x10 Ryan, et al. 1991... 

As with most items on a vacuum line that contain mercury, place the Toepler pump in a secondary container that is firmly attached to another surface to contain any mercury that may spill from an accident as well as protect the pump from accidental bumps (see Fig. 7.28). Plastic containers (such as plastic milk cartons) are particularly good because the mercury will not affect plastic. Conversely, mercury may amalgamate with the metals in a metal can, which could destroy any containment capabilities. In addition, it is easier to get mercury out of a plastic container (with smooth walls) than out of a metal one (with a narrow rim). The plastic tub can be glued onto the table with some epoxy. The epoxy will stick better if you roughen up the bottom surface of the plastic container with sandpaper. Because not all epoxies stick to plastic, test the epoxy before assuming that it will hold. 

Packaging material was examined as a potential contamination source for food after migration of PCDD/Fs from chlorine-bleached cartons into milk had been demonstrated.49 Other studies confirmed that PCDD/Fs carried over from bleached milk cartons and bleached coffee filters.50,51 Ffowever, the paper industry recently agreed to reduce the amount of PCDDs and PCDFs in bleached paper products to below lpg TEQ g 1 (ppt) therefore, migration of PCDD/Fs from milk packaging material is no longer considered a source of concern. 

Melt index is close to 3.5, tensile strength about 1,500 psi (6.9 MPa), melting point of 99 to 100C, and needle penetration test at 25C is 1 to 10. Just over 10wt% of LDPE produced in the USA find use in typical wax applications, such as paper coatings and floor polishes. A major use is coated paperboard for milk cartons. 

A typical construction of a coated board milk carton would be (from outside to inside) LDPE/paperboard/ionomer/aluminium foiEionomer/LDPE. 

All rubbers, glasses, and plastics are polymers. You are probably familiar with natural polymers like cellulose (the building block of plant fibers) and synthetic polymers like polyethylene (plastic milk cartons), polyisoprene (automobile tires), polyethylene terephthalate (soft drink bottles), polymethyl methacrylate (Plexiglas ), polyvinylidene chloride (transparent plastic wrap), polytetrafluoroethylene (Teflon ), and various polyesters (fabrics). Polyvinyl chloride, the polymer shown earlier, is used to make rigid pipes, house siding, and protective coverings for automobile seals and dashboards, among many other applications. 

If you are going to store dynamite, a good Idea Is to store it in a cool place and turn It over once a month. It will take more than a month to start leaking, but it is better to be safe than sorry. Also It Is a good Idea to store It In a leak proof carton, such as a milk carton, so that in case It does leak, the nltro wMI be contained and It won t run out all over the place. 

Examples Jean asked why no one makes a paper milk carton that opens without tearing. 

Some of the procedures of value for processing of mixed plastic wastes may also be useful for the recovery of value from the laminates used for efficient packaging of food and beverages (e.g., milk cartons, Tetrapaks). A combination of heat and pressure may be employed on a recycle stream of this type of material to fuse the mixed fibrous and resin components into a dense board-like product [31, 32]. This highly weather and insect resistant product, Eco Superwood Plastic Lumber, may be sawn, nailed, drilled, etc., like wood, and it resists rotting in direct contact with the soil without the need for preservatives. 

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