Abstract: A surface winder for forming mill rolls of sheet material such as polystyrene foam sheet features a surface winder with an automatic web or sheet material transfer arrangement whereby a full mill roll is displaced and replaced by an empty core. The empty core automatically receives the severed end of the web and the winding operation continues on the empty core in an uninterrupted fashion.

Abstract: Improvements in the production of foam form film or sheeting plastic products in order to increase the flexibility characteristics thereof by reducing the size of the voids and increasing the number of voids therein without substantially changing the bulk density, production rate or product size and by reducing the rate at which such foamed products solidify after formation.

Abstract: The present invention relates to a method and apparatus for the extrusion of tubular thermoplastic film which comprises extruding a melt of thermoplastic through an annular orifice to form a bubble or tube and while the tube is still in a semimolten condition, passing the tube through an extrusion cooling and shaping means having a plurality of multi-perforated air rings shaped in congruance to the desired shape of the inflating tube. This method allows increased production speeds and minimized gauge variation while maintaining bubble stability.

Abstract: Stability of a thermoformed foam meat tray, especially to overwrapping by machine, is enhanced by a circumferential flange of the side walls of generally V-shaped cross section to terminate at approximately the plane of the bottom of the tray. Full nestability is afforded by upper surfaces of the flange at an angle to each other smaller than the corresponding angle between lower surfaces of the flange.

Abstract: An adhesive closure for bags, such as sandwich bags for example, comprising an adhesive stripe located adjacent the open mouth portion of the bag. The adhesive stripe is covered until ready for use by the upper portion of the bag's front wall whereby upward displacement of the front wall exposes the adhesive stripe for sealing the upper portion of the bag walls together.

Abstract: A self-draining saucer is provided by combination of two concave discs (saucer shape). The lower disc has a central well defined by a depressed central bottom and circular wall. The upper disc is formed such that its bottom convex surface generally follows the concave upper surface of the lower disc. A vertical surface on the under side of the upper disc frictionally engages a similar surface inside the lower disc to retain the pair. Holes are provided through the top disc above the well in the lower disc for drainage of spilled liquid into the well. The combination is easily formed of thermoplastic resin and assembled on standard thermoforming machinery.

Abstract: A plastic bag such as trash can liners, grass and leaf bags, sandwich bags and the like is reinforced by placing spaced ribs therein, integral with the wall structure, the ribs having a rib-to-rib spacing in the order of 1/8 to 2 cm, the ribs being peaked and merging smoothly from a projecting peak to the thickness of the walls between the ribs, the peaks extending about 1.5 to 10 times the wall thickness of the film which is, preferably, in the order of about 0.4 to 2.0 mils. Upon extrusion, the extrusion die is formed with small notches with rounded corners so that the ribs are extruded while the film material is extruded, and provide additional material in the region of the ribs which merges smoothly with the material being extruded to form the film. Such rib-reinforced bag structures may be produced by forming a continuous roll of such bags, the individual bags in such a roll being readily separated along predetermined lines of weakness.

Abstract: Heat seals of improved delamination resistance are provided having increasing adhesion across the width of the seal band. The seals are produced by using a heat seal means having a temperature profile such that there is a temperature gradient in the seal width direction.

Abstract: The present invention relates to a method for shrink packaging relatively large objects such as, for example, a pallet load utilizing heat shrinkable thermoplastic structures. The thermoplastic bags are characterized by having a rectangular bottom configuration whereby when the bag structure is shrunk about the generally rectangular pallet load, the contour of the shrunken thermoplastic overwrapped material conforms substantially to the rectangular conformation of the pallet being overwrapped.

Abstract: A thermoplastic foamed resin extruding operation is described which uses an inner die lip machined to vary the width of the die annulus or opening so that varying thicknesses or mass concentrations or densities of preselected desired width will be formed in the extruded resin sheet obtained therefrom. The mass concentration variations in the extruded sheet are coordinated with a downstream thermoforming operation involving deep and shallow draw forming or different sheet fabrications such as folding, scoring, cutting, etc.

Abstract: In a method and apparatus for the extrusion of thermoplastic resinous materials and in particular coarse granular resinous materials which contain admixed therewith fine, powdery additives, a seal is provided for the extrusion apparatus to prevent escape or leakage therefrom of the fine powdery additive material admixed with the coarser granular resin.

Abstract: The present invention relates to a method for the extrusion of tubular thermoplastic film which comprises extruding a melt of thermoplastic through an annular orifice to form a bubble or tube and while the tube is still in a semimolten condition, passing the tube through an extrusion cooling and shaping means having a plurality of multi-perforated air rings shaped in congruance to the desired shape of the inflating tube. This method allows increased production speeds and minimized gauge variation while maintaining bubble stability.

Abstract: A packaging tray, especially adapted for the containment of moisture containing food products such as meat, poultry and fresh produce comprising a bottom supporting surface having a plurality of spaced apart liquid entrapping recesses. The individual recesses have a larger cross-sectional area at their base than at their top.

Abstract: A method and apparatus for the production of improved heat seals in thermoplastic materials which includes causing displacement of thermoplastic material in the area being sealed during the sealing operation. The displaced thermoplastic serves to reinforce that area of the seal which is normally weakened as a result of the heat sealing step.

Abstract: A method is provided for preparing continuous, seamless blown thermoplastic film tubing by extruding a melt of the thermoplastic through an annular orifice into an instantaneous cylindrical shape, inflating the film tube thus formed and cooling such inflated tubing. In the process, the extruded tube while still plastic is passed through an external cooling and shaping means having a multi-perforated air ring shaped in congruance to the desired shape of the inflating tube. A major advantage of this process is that production speeds can be increased while maintaining bubble stability.This is a Division of application Ser. No. 366,388, filed June 4, 1973, now U.S. Pat. No. 3,867,083 issued on Feb. 18, 1975.

Abstract: A thin gauge plastic cover having a downwardly depending, outwardly flaring side wall the upper portion of which is integrally joined to an annular top. The cover top has a plurality of combination ventilation and finger holes. The cover is also provided with a lower arcuate locking rim provided with a plurality of cut-away portions to allow the rim to expand in diameter when it is locked over the periphery of a circular plate. The cut-away portions of the locking rim also expose portions of the plate rim to permit manually restraining the plate when the cover is being removed from the plate.

Abstract: Improvement in the process and apparatus of Application Ser. No. 236,766 filed Mar. 21 1971, now U.S. Pat. No. 3,769,124. There is described a technique for butt welding a trailing end of one roll of thermoplastic film or sheet material to the leading edge of another roll of such material by vertically superimposing the trailing and leading portions of the two rolls, aligning the lateral edges of such portions over a significant distance sufficient to insure angular alignment of the two rolls at the butt weld. Severing the two portions along a coincident transverse line, heating the severed portions to an extent sufficient to weld such together, and bringing the heated transverse edges of the two portions together while maintaining lateral edge alignment of said portions, whereby butt welding such into a continuous sheet.

Abstract: A method and apparatus are provided to continuously monitor and measure the average size of individual foam cells contained in a foam structure, such as polystyrene foam for example, as it is being fabricated. Such an arrangement permits the prompt adjustment of process conditions and/or the concentration of nucleating agents in the extrusion system in the event the foam cell size deviates from a preselected norm. The method comprises illuminating the surface of a foam sheet, receiving and collecting at least a portion of the light which is diffused and reflected from the foam sheet with a detector photocell, electrically measuring the amount of light energy received by the photocell and converting such measurements into a cell size measurement.

Abstract: A thermoplastic bag comprising a front wall and a rear wall. The upper edge of said rear wall is turned inwardly and the resultant downwardly facing pouch is sealed along its edges to the upper edges of the rear bag walls. The upper portion of the front bag wall has an adhesive stripe extending across the width thereof. The adhesive stripe is protected from direct contact with the pouch on the opposite wall, until it is desired to close and seal the bag, by means of a strip of release paper covering the adhesive or, alternatively, by folding a portion of the front bag wall back upon itself to cover the adhesive stripe.

Abstract: A resinous blend composition, and thermoplastic film structures fabricated therefrom having improved physical properties, comprising a polyolefin (e.g., polypropylene & copolymers thereof with ethylene) containing a minor amount based on the weight of the polyolefin and sufficient to improve the heat sealing characteristics of films fabricated from such blends, of a normally solid, resinous, random multipolymer of a mixture comprising pentadiene, 1,3 and at least one other hydrocarbon compound containing ethylenic unsaturation copolymerizable therewith. Examples of such ethylenically unsaturated hydrocarbons include cyclopentadiene, isoprene, 2-methylbutene-2, tertiary butylstyrene, .beta.-pinene, dipentene, .beta.-phellandrene, .alpha.-methylstyrene, and mixtures thereof.