Method for making a multi-layer plastic container with a handle

Abstract: The method and apparatus for making a multi-layer plastic bottle with a handle for holding liquids and the like which comprises enclosing a hollow parison of molten plastic which is at a blow molding temperature, pinching a portion of the hollow parison as the mold closes to form a hollow moil portion and neck portion, simultaneously pinching a portion of the hollow parison to form a hollow handle portion while leaving a portion of the parison to provide a passage 30 from the moil portion 16 to the handle portion 14 and thereafter expanding the parison through the moil portion to form the container.

Description: This invention relates to blow molding hollow plastic articles and particularly to blow molding hollow plastic articles with integral handles. Background and Summary of the Invention In the blow molding of hollow plastic articles, it has been common to close a hot tube within a mold and blow a hollow container with an integral handle. Where the tube comprises a single layer of plastic, this is readily achieved by pinching off the plastic in the area that forms the hollow of the handle. However, where a multi-layer plastic is desired, as, for example, where there is an intermediate plastic layer required for providing properties such as permeability or other properties as, for example, are required for containing solvent based products, it has been found that in order to weld the pinch off areas, a large and unsightly pinch off must be provided which not only is unsightly but forms a seam line that makes the handle uncomfortable to hold. In addition, this construction weakens the drop test performance of the container. Accordingly, the object of the present invention is to provide a method and apparatus for forming multi-layer containers having an integral handle which provide for proper pinch off; which avoid large uncomfortable and unsightly pinch offs; which have adequate drop test performance; and which minimize the number of handling steps in the formation of the bottle. In US-A-3,640,672 a blow-molded container having an integral handle is produced by means of a special blow tube, the blow tube having one opening for blowing the body of the container and another, positioned in the handle-forming part of the mold, for blowing the handle. According to US-A-3,342,916 a hollow handle is formed on a hollow water cooler cover by a "satellite" chamber formed between the handle and the main body, air injected into the satellite chamber passing through passages to form first the handle and then the main portion of the cover. In the method disclosed in US-A-3,892,828 a container having an integral handle is made by blowing a parison laminate having a high strength inner lamina and a low strength outer lamina. US-A-3,366,290 describes a plastic container with a hollow L-shaped handle which is made by vacuum forming two half-sections provided with integral flanges, placing the half-sections together and heat-sealing the flanges. According to US-A-3,444,285 a hollow plastics container with an integral handle is formed by blowing a plastic parison into shape within a partible mold an internal section of a wall of which partially collapses a portion of the parison into flash material. In accordance with the invention the above object is attained by the method as defined in claim 1 by the apparatus as defined in claim 4 and by the article as defined in claim 5. More specifically the invention provides a method for making a plastic container which comprises providing a hollow parison of molten plastic material at a blow molding temperature, pinching a portion of the hollow parison between mold sections to form a hollow moil portion, an integral neck portion and a body forming portion, said moil portion communicating with said body portion through said neck portion, forming an integral hollow handle portion connected to said body portion during said pinching by an integral double layer wall portion, said integral wall portion isolating said handle portion from said body portion, forming a passage extending between the moil portion and said handle portion, thereafter expanding the parison by applying gaseous pressure to the moil portion such that gaseous pressure passes through the moil portion to the neck portion then through the neck portion to the body portion to form the container, and through the moil portion to the said passage and then through said passage to the handle portion to expand the handle portion. Apparatus for making a plastic container with a handle by this method comprises mirror image mold sections positioned to close about a hollow parison, each said mold section including a hollow portion positioned to define the body of the container, a generally semi-circular portion positioned to define the finish of the container, a continuous groove for defining part of the handle, a shallow groove for defining a wall surrounded by the handle, an upper cavity for defining part of a moil portion and a groove for providing a passage in the blown container between the moil cavity and the grooves which cooperate to define the handle, said semi-circular portion providing a passage in the blown container between the moil cavity and the body cavity, said mold further including a guide portion for receiving a blow pipe for supplying gaseous pressure to the moil portion. The invention also provides a hollow blown plastic article comprising a hollow body portion, an integral neck portion, an integral hollow handle portion connected to the body portion by an integral wall, an integral hollow moil portion connected to the handle portion and the neck portion by said integral wall, said neck portion providing a passage in the blown article between the moil portion and the body portion, and an integral passage in said integral wall communicating between the moil portion and the hollow handle portion. Description of the Drawings Fig. 1 is a perspective view of a container embodying the invention. Fig. 2 is a perspective view of the container after it is blown and prior to being trimmed. Fig. 3 is a fragmentary elevational view of the container. Fig. 4 is a fragmentary sectional view taken along the line 4-4 in Fig. 3. Fig. 5 is a fragmentary plan view of a mold for forming the container. Fig. 6 is a fragmentary plan view showing the container in a mold section after it has been blown. Fig. 7 the fragmentary sectional view taken along the line 7-7 in Fig. 6 with the other mold section in position. Fig. 8 is a fragmentary sectional view taken along the line 8-8 in Fig. 6 with the other mold section in position. Description Referring to Fig. 1, the container 10 made in accordance with the invention comprises a hollow body 11 having a neck or finish 12 with fastening means for engaging a cap such as threads 13 thereon, an integral hollow handle 14 and a wall 15 connecting the handle 14 to the body 11. Referring to Fig. 2, as the container 10 is formed, as presently described, it includes a hollow moil portion 16 which is connected to both the handle portion 14 (Fig. 8) and the finish 12 (Fig. 7). In addition, flat plastic portion 17 closes the finger receiving opening of the handle (Fig. 8). The container thus must be trimmed to provide the configuration such as shown in Fig. 3 by removing the moil portion 16 and plastic portion 17. As can be seen from Fig. 4 which is a greatly enlarged section through the handle, the handle 14 is a multi-layer handle having a smooth continuous surface 18 and the layers of plastic are joined to form the double layered wall 15 that connects the handle to the body 11 of the container 10. The container is formed by expanding a parison within the sections of a mold. Referring to Fig. 5, one mold section 20 is shown and comprises a hollow portion 21 which is adapted to define the body of the container, a generally semi-circular portion 22 adapted to define the finish 12, a continuous groove 23 for defining part of the handle, a shallow groove 24 for defining the wall 15 and an upper cavity 25 for defining part of the moil portion 16. The mold section 20 further includes a small groove 26 for providing communication between the moil cavity 25 and the groove 23. Finally, the section 20 includes a guide portion 27 for receiving a blow pipe 28. The parison may comprise an extruded tube of plastic at blow molding temperature. When the sections of the mold are closed about the parison, the lower portion of the parison is pinched by a severe pinch off for defining the body 11 of the container, the upper portion is pinched for defining the moil portion 16, an intermediate portion is pinched for defining the handle 14, the wall 24 and the portion 17 while the groove 26 defines a passage 30 between the moil portion 25 and the groove 23. Thus when the blow pipe 28 is inserted to blow the container, as shown in Fig. 6, the expanding fluid can flow from the interior of the hollow moil 16 to the interior of the body 11 and also through the hollow portion 29 defined by the passage 30 to the interior of the handle so that the handle is blown outwardly. After the blow molding, the container is removed from the mold and trimmed by severing the moil portion 16, wall portion 17 and trimming the finish 12. The resultant container has a handle which does not have a rough seam line in the area of the upper portion of the handle (Fig. 4) which is engaged by the fingers. The severe pinch off in the wall 15 required for maintaining properties, such as permeability, is at the area not engaged by the fingers. Therefore, the container is more comfortable to hold and is not unsightly, has adequate drop test performance and has been made with a minimum of handling steps.

Claims: A method for making a plastic container which comprises providing a hollow parison of molten plastic material at a blow molding temperature, pinching a portion of the hollow parison between mold sections to form a hollow moil portion (16), an integral neck portion (12) and a body forming portion (11), said moil portion (16) communicating with said body portion (11) through said neck portion (12), forming an integral hollow handle portion (14) connected to said body portion (11) during said pinching by an integral double layer wall portion (15), said integral wall portion (15) isolating said handle portion (14) from said body portion (11), forming a passage (30) extending between the moil portion (16) and said handle portion (14), thereafter expanding the parison by applying gaseous pressure to the moil portion (16) such that gaseous pressure passes through the moil portion (16) to the neck portion (12) then through the neck portion (12) to the body portion (11) to form the container, and through the moil portion (16) to the said passage (30) and then through said passage (30) to the handle portion (14) to expand the handle portion (14). A method as claimed in claim 1 wherein the hollow parison is a multi-layer parison. A method as claimed in claim 1 or 2 including the step of trimming the hollow moil portion (16), the neck portion (12) and the area (17) surrounded by the handle. An apparatus for making a plastic container with a handle by a method as claimed in claim 1 comprising mirror image mold sections (20) positioned to close about a hollow parison, each said mold section including a hollow portion (21) positioned to define the body of the container, a generally semi-circular portion (22) positioned to define the finish of the container, a continuous groove (23) for defining part of the handle, a shallow groove (24) for defining a wall surrounded by the handle, an upper cavity (25) for defining part of a moil portion and a groove (26) for providing a passage in the blown container between the moil cavity and the groove (23) which cooperates to define the handle, said semi-circular portion (22) providing a passage in the blown container between the moil cavity and the body cavity, said mold said mold further including a guide portion (27) for receiving a blow pipe for supplying gaseous pressure to the moil portion. A hollow blown plastic article comprising a hollow body portion (11), an integral neck portion (12), an integral hollow handle portion (14) connected to the body portion (11) by an integral wall (15), an integral hollow moil portion (16) connected to the handle portion (14) and the neck portion (12) by said integral wall (15), said neck portion (12) providing a passage in the blown article between the moil portion (16) and the body portion (11), and an integral passage (30) in said integral wall (15) communicating between the moil portion (16) and the hollow handle portion (14). A blown article as claimed in claim 5 wherein said integral wall (15) comprises a double layer of plastic, each layer being multi-layered.

Inventors: KRALL THOMAS J, MYERS ROBERT A, KRALL, THOMAS J., MYERS, ROBERT A.
Applicants: OWENS ILLINOIS PLASTIC PROD, OWENS-ILLINOIS PLASTIC PRODUCTS INC.
Application year: 1991
Main classification: B29C49
IPC codes: B29C49, B65D23