Dust-proof carton

Claim 1

A SEAL-END DUST-PROOF RECTANGULAR CARTON HAVING OPPOSITELY DISPOSED FRONT AND BACK WALLS, TWO OPPOSITELY DISPOSED SIDE WALLS, AND END CLOSURES COMPRISING NARROW END FLAPS EXTENDING INWARDLY FROM THE FRONT AND SIDE WALLS IN SUBSTANTIALLY THE SAME PLANE, THE ADJACENT ENDS OF THE SAID NARROW END FLAPS BEING MITERED TO AN ANGLE OF BETWEEN ABOUT 42* AND 44* WITH RESPECT TO THEIR LINE OF ARTICULATION, THE OTHER END OF THE NARROW END FLAPS EXTENDING FROM THE SIDE WALLS BEING SQUARED AT AN ANGLE OF ABOUT 90* WITH RESPECT TO THEIR LINE OF ARTICULATION, BROAD END FLAPS EXTENDING INWARDLY FROM BOTH ENDS OF THE BACK WALL AND BEING APPROXIMATELY EQUAL IN SIZE TO THE CROSS-SECTION OF THE SAID CARTON, SAID BROAD END FLAPS OVERLAPPING THE SAID NARROW END FLAPS AND BEING BONDED THERETO WITH A THERMOPLASTIC ADHESIVE, SAID ADHESIVE BEING SOLID BUT FLEXIBLE AT ROOM TEMPERATURE AND GARDUALLY SOFTENING TO A FLUID STATE ABOVE 200* F., AN EXCESS OF THE SAID ADHESIVE LYING BETWEEN THE SAID ADJACENT MITERED ENDS OF THE NARROW END FLAPS AND FORMING AN INTEGRAL PART OF THE SAID CARTON, AND A DOUBLE THICKNESS OF ADHESIVE INTERPOSED BETWEEN THE WQUARE ENDS OF THE NARROW FLAPS EXTENDING FROM THE SIDE WALLS AND THE SUPERPOSED PORTION OF THE BROAD END FLAPS WHEREBY A CARTON WITH DUSTPROOF CORNERS IS FORMED.