Abstract: Low-density, high service temperature polymer foam is extruded by heating a crystalline polymer resin above its crystalline melt point to melt the resin, selecting a blowing agent combination, combining the blowing agent combination with the resin to create a mixture, cooling the mixture to a temperature approaching a freezing temperature for the mixture, and extruding the foam through a die. The blowing agent combination is made up of 50 to less than 100 mole percent of a first blowing agent having a boiling temperature at STP of greater than 310° K, and more than 0 to 50 mole percent of a second blowing agent having a boiling temperature at STP of less than 310° K. The blowing agent combination has an equilibrium solubility vapor pressure in the polymer of less than 45 atm at the foaming temperature and greater than or equal to 1 atm at the glass transition temperature.

Abstract: A crystalline polymer resin, such as poly(ethylene terephthalate), is heated to melting. One or more blowing agents is selected wherein at least one of the blowing agents has a boiling point greater than the glass transition temperature for the resin and less than the forming temperature, such as the temperature of the mold used to form the useful article. The blowing agent(s) and resin are combined to create a mixture with a blowing agent concentration sufficient to produce a theoretical sheet foam density of less than 0.4 g/cm3. The mixture is cooled to a temperature approaching the freezing point of the mixture, and then extruded into a substantially uniform closed cell polymer foam sheet of density less than 0.4 g/cm3. The extruded sheet is then cooled by direct contact with a cooling surface at a surface temperature below the glass transition temperature such that the blowing agent(s) condenses and the sheet has a density of greater than 0.4 g/cm3 and a sheet crystallinity of less than 15%.

Abstract: PET foam is processed into flakes. The flakes are densified in a pellet mill at between about 300.degree. F. and about 350.degree. F. to produce pellets. The pellets are then dried in a desiccant dryer at about 350.degree. F. for about 6 hours, so that the dew point of the pellets reaches about -40.degree. F. The dried pellets have an intrinsic viscosity about equal to virgin PET and a crystallinity greater than 20%. This material can be reused as if it were virgin PET.

Abstract: A container (e.g., for food) has a top portion, a bottom portion connected to the top portion by a hinge, and a closure opposite the hinge. The closure is a tab-and-slot type, with the tab curved in a direction away from the slot to encourage closing and discourage opening of the container. A beveled edge on the top surface serves as a designated pressure-application area for a user's thumb, assisting with opening and/or closing of the closure with one hand. Mating step-type peripheral flanges in the top and bottom slope upward from the hinge to the closure to create a multi-level seal that gets larger near the closure. The step shape of the top flange also helps create a channel in the top that catches any liquid spilled on the container, and barriers on either side of the closure in the channel discourage the liquid from entering the container through the closure.

Abstract: Low-density, high service temperature polymer foam is extruded by heating a crystalline polymer resin above its crystalline melt point to melt the resin, selecting a blowing agent combination, combining the blowing agent combination with the resin to create a mixture, cooling the mixture to a temperature approaching a freezing temperature for the mixture, and extruding the foam through a die. The blowing agent combination is made up of 50 to less than 100 mole percent of a first blowing agent having a boiling temperature at STP of greater than 310.degree. K, and more than 0 to 50 mole percent of a second blowing agent having a boiling temperature at STP of less than 310.degree. K. The blowing agent combination has an equilibrium solubility vapor pressure in the polymer of less than 45 atm at the foaming temperature and greater than or equal to 1 atm at the glass transition temperature.

Abstract: A crystalline polymer resin, such as poly(ethylene terephthalate), is heated to melting. One or more blowing agents is selected wherein at least one of the blowing agents has a boiling point greater than the glass transition temperature for the resin and less than the forming temperature, such as the temperature of the mold used to form the useful article. The blowing agent(s) and resin are combined to create a mixture with a blowing agent concentration sufficient to produce a theoretical sheet foam density of less than 0.4 g/cm.sup.3. The mixture is cooled to a temperature approaching the freezing point of the mixture, and then extruded into a substantially uniform closed cell polymer foam sheet of density less than 0.4 g/cm.sup.3. The extruded sheet is then cooled by direct contact with a cooling surface at a surface temperature below the glass transition temperature such that the blowing agent(s) condenses and the sheet has a density of greater than 0.4 g/cm.sup.

Abstract: A container (e.g., for food) has a top portion, a bottom portion connected to the top portion by a hinge, and a closure opposite the hinge. The closure is a tab-and-slot type, with the tab curved in a direction away from the slot to encourage closing and discourage opening of the container. A beveled edge on the top surface serves as a designated pressure-application area for a user's thumb, assisting with opening and/or closing of the closure with one hand. Mating step-type peripheral flanges in the top and bottom slope upward from the hinge to the closure to create a multi-level seal that gets larger near the closure. The step shape of the top flange also helps create a channel in the top that catches any liquid spilled on the container, and barriers on either side of the closure in the channel discourage the liquid from entering the container through the closure.

Abstract: A formed plastic container having a cover portion and a bottom portion, also includes a latch. The latch has a projection extending out from the cover, and a locking flap extending out from the bottom that flexes to meet and hold the projection. In one embodiment, the projection includes a tab, and the locking flap includes a rib that lifts the flap above the tab when closed, in order to reduce the possibility of the tab coming away from the flap.

Abstract: A container for housing a food dish includes a receiving shell defining a first cavity and a cover shell that is releasably lockable to the receiving shell for providing a cover with a second cavity over the first cavity. The cover shell has side walls with inward projections for entrapping the food dish seated within the receiving shell when the cover shell is releasably locked to the receiving shell.