MXPA96004105A

MXPA96004105A - Bottle of plastic, molded, and a method to make my

Info

Publication number: MXPA96004105A
Application number: MXPA/A/1996/004105A
Authority: MX
Inventors: Petre Jeanmarie; Colloud Alain
Original assignee: Societe Anonyme Des Eaux Minerales D'evian
Priority date: 1994-03-16
Filing date: 1995-03-13
Publication date: 1998-02-01

Abstract

The present invention relates to a molded plastic bottle, comprising a neck designed to receive an upper part, a substantially cylindrical side wall, and a bottom formed with a central or canted portion and a convex peripheral surface, which includes radial grooves and which is connected to the concave central portion of the bottom via a substantially planar annular surface, the bottle is characterized in that the bottom of each slot is substantially and tangentially connected to said annular surface.

Description

PLASTIC BOTTLE. MOLDED. AND A METHOD TO DO THE SAME DESCRIPTION OF THE INVENTION The invention relates to a molded plastic bottle, designed in particular to contain still water or not to aerate, or some other non-aerated liquid. It also refers to a mold for making said bottle. The bottles of this type are made of a plastic material such as, for example, PET (polyethylene terephthalate), PVC (polyvinyl chloride), or other material, using well-known techniques of blow molding by injection or blow molding. by extrusion. The bottles generally include a neck, designed to receive a closure cap, a cylindrical wall having a transverse curvature, and a bottom having a shape designed to impart a certain amount of resistance thereto. In particular it is known to form a central, meshed, round portion at the bottom of such a bottle, said portion being connected to the cylindrical side wall of the bottle via an annular surface, convex, so that it can be stopped, which includes grooves or reinforcement ribs (as described for example in French patents 2 219 077 and 2 300 707). However, these funds are always the weak point of the bottles. In particular, the vertical drop tests of full bottles shows that the fracture or rupture regime of the bottom is approximately 70% for a bottle made of PVC that falls on its bottom from a height of one meter. Another disadvantage of said known funds is their low resistance to high internal pressure, as a result of an increase in the storage temperature of the complete bottles and / or shrinkage of the plastic material of the bottles during two or three weeks after their manufacture and filling. The high internal pressure, in a hermetically sealed bottle, results in the bottom becoming deformed and the bottle unstable. In addition, currently, bottles of this type are packaged and transported in stacked and spliced loads, so that the bottoms of the bottles of the upper layers of a load rest on the upper parts of the bottles of the lower layers and are they are subjected to dents and punctures by the lower layers, which can cause the funds to break or become permanently deformed, the bottles to tilt in the load, and the spliced loads to be unstable. A particular object of the invention is to avoid or at least reduce these disadvantages. The invention provides a molded plastic bottle having a bottom that exhibits improved stability and improved resistance to dents.

Up to now, the invention proposes a molded plastic bottle, comprising a neck designed to receive an upper part, a substantially cylindrical side wall, and a bottom formed with a concave or meshed central portion, and a convex peripheral surface including grooves radially and which is connected to the concave central portion of the bottom via a substantially planar annular surface, the bottle is characterized in that the bottom of each radial groove is substantially and tangentially connected to said flat annular surface. In the present invention, the curvature of a surface is always defined from the inside to the outside of the bottle, in this way, a concave surface has its concave face facing the outside of the bottle, and a convex surface presents his convex face looking towards the outside of the bottle. It has been observed, surprisingly, that a bottle bottom, having the above defined configuration, has both increased stability and resistance to internal pressure and puncture efforts, which are considerably greater than those obtainable in the prior art. . This is particularly because the grooves are tangentially connected to the flat surface of the bottom, whereby it is possible to avoid or considerably reduce the deformation of the bottom under the effect of pressure variations inside the bottle, thus guaranteeing its stability.

Advantageously, the radwidth of said flat annular surface is greater than the radius of the concave central portion of the bottom of the bottle, and the diameter of said concave central bottom portion is smaller than the diameter of the upper part, which is provided in the neck of the bottle. In a preferred embodiment of the invention, the convex peripheral surface of the bottom is connected to the flat annular surface via a concave annular surface, and to the side wall of the bottle via a convex cylindrical surface, whose generating line is a circular arc which It has a large radius of curvature. At one end, the bottom of each radgroove formed in the convex peripheral surface is tangenty connected to the connecting surface between said flat annular surface and said convex peripheral surface. At its other end, the bottom of each radgroove is connected to the wall of the bottle via a concave surface. In general, said bottom shape of a molded plastic bottle allows its resistance to dents and increased internal pressure to be improved by a factor of 1.5 to 2, and the invention is applicable to bottles having bottoms that they are circular or in some other way, v. gr. , substanty square or rectangular, polygonal or other. The invention also provides a mold for making a bottle of the type described above, said mold comprising a bottom wall formed with a central convex or projecting surface, a concave peripheral surface, including radribs, and a substanty planar annular surface connecting the surface central with the concave peripheral surface, the mold is characterized in that the upper part of the radribs connects substanty and tangenty with said flat annular surface. The racwidth of the flat annular surface of the bottom of the mold is preferably greater than the radius of the central projection surface of the bottom of the mold. The characteristics of the bottom of the bottle are usually found in the bottom of the mold with inverted curves in shape. The invention will be better understood, and other features, details and advantages thereof, will appear more clearly reading the following description, presented by way of example, and with reference to the accompanying drawings, in which: Figure 1 is a view in diagrammatic elevation of a bottle, made of a plastic mater to which the invention is applied; Figure 2 is a diagrammatic average view on a larger scale, in axsection, of the bottom of said bottle; Figure 3 is a fragmentary cross-sectional view on line lll-lll of Figure 2; Figures 4 and 5 are diagrammatic, elevation and lower plan views of a bottle with a substanty rectangular section; and Figure 6 is a diagrammatic fragmentary view in axsection of a mold for making a bottle of the invention. The bottle 10 of Figure 1, designed to contain still or non-aerated mineral water, is in a conventional manner and is made of a conventional mater such as PET (polyethylene terephthalate) by blow molding by injection or blow molding. extrusion The bottle essenty comprises a threaded neck 12 designed to receive a threaded sealing cap 14, a tapered upper portion 16, connecting the neck 12 to a cylindrical lateral wall 18 of circular cross-section, and a bottom 20, the cylindrical lateral wall 18 of the bottle being formed with a transverse reinforcing curvature 22 and with a clamping waist 24 provided substanty at half height. The bottom 20 of the bottle (Figure 2) has a circular indented contour and comprises a meshed central portion 26, concave in shape (its concave face facing the outside of the bottle, as indicated above), which is connected to the side wall 18 of the bottle successively via a flat annular surface 28 and via a convex peripheral surface 30, which forms a support surface for the bottle to remain straight on any support 32, the bottom of the bottle further comprises an annular, concave connecting surface, 34, between the flat annular surface 28 and the convex peripheral surface 30, and a cylindrical convex connecting surface 36 between said convex peripheral surface 30 and the cylindrical wall 18 of the bottle. On the convex peripheral surface 30, radial grooves 38 are formed, said grooves (which are grooves on the outside of the bottle and which form projection ribs on the inside of the bottle) being regularly spaced around the periphery of the bottle. the convex surface 30, its number is on the scale of 6 to 20, and preferably being 9, 10 or 1 1. More precisely, the bottom profile of the bottle, in axial section, can be defined as follows, with reference to Figure 2: The convex cylindrical surface 36, which connects the vertical cylindrical wall 18 of the bottle with the convex surface 30 to stand on the support, has a circularly arched generating line, with a radius of curvature R 1, which is relatively large, v. gr. , approximately 90 mm, when the radius of the cross section of the indian cylindrical wall 18 is approximately 45 mm. The profile of the convex surface 30 is a circular arc of radius R2, e.g. , approximately 7 mm in the aforementioned example, which tangentially connects with the circular arc of radius R 1 defining the surface 36. The circular arc of radius R 2 defines the profile of the convex surface 30 which is tangentially connected with the circular arc of radius R3 defining the profile of the concave annular surface 34, said radius R3 being approximately 20 mm in the aforementioned example. The circular arc of the radius R3 defining the profile of the surface 34, is connected tangentially with the flat annular surface 28, which extends perpendicularly to the longitudinal axis 40 of the bottle, the distance d between said flat annular surface 28 and the flat tangential transverse to the convex surface 30, being from about 3 mm to 4 mm, in the aforementioned example. The concave central portion 26 of the bottom is defined in axial section by a circular arc of radius R4, which is about 9 mm, in the aforementioned example, said concave circular arc of radius R4 connecting to the flat annular surface 28 via a convex annular surface 42 having a profile in axial section, which is defined by a circular arc of radius R5 having a value of approximately 5 mm in the aforementioned example. Each radial groove 38 has a V-shaped cross section (Figure 3) with a round bottom 44, the side walls 46 of each groove making between them an angle of about 70 ° in the aforementioned example, and connecting with the convex surface 30 via round portions 48 of small radius of curvature (approximately 1 mm in the aforementioned example). The number of radial grooves 38 is in the range of 6 to 20, the angle in the center a between the axes of two consecutive grooves is in the range of 60 ° to 18 °.

The bottom profile 44 of each radial rib can be defined (Figure 2) by a convex circular arc of radius R6 which is tangentially connected to the flat annular surface 28 via a concave circular arc of radius R7, and which is connected to the surface cylindrical 36 via a concave circular arc of radius R8 and a convex circular arc of radius R9, the circular arc of radius R9 tangentially connecting with the circular arc of radius R1 of surface 36, and with the circular arc of radius R8, this same circular arc of radius R8 connecting tangentially to the circular arc of radius R6. The bottom 44 of each radial rib is tangentially connected with the flat annular surface 28 of the bottom of the bottle and with the concave annular connector surface 34 between said flat annular surface 28 and the convex surface 30 so that it stands on a support 32. This is why the bottoms of the grooves 38 are tangentially connected with the flat annular surface 28, so that it is possible to avoid the deformation directed upwards and downwards of the bottom under the effect of variations of pressure inside a sealed full bottle , and that the flat portion 28 of the bottom can be maintained at a distance, d, substantially constant from the support surface 32 of the bottle (pressure variations due to material shrinkage or temperature variations being less than 0.5 bar for a bottle containing calm water), said distance remaining substantially the same regardless of whether the bottle is full or empty. In the aforementioned numerical example, the radius R6 may be about 5 mm, the radius R7 about 45 mm, the radius R8 about 5.5 mm, and the radius R9 about 1.5 mm. The concave central portion 26 of the bottom of the bottle has a diameter substantially smaller than that of the upper part 14 of the bottle (eg, from about 18 mm to 20 mm, when the top has a diameter of about 30 mm. ) and is connected to the flat annular surface 28, which has a radial width or degree that is advantageously greater than the radius of the concave central portion 26 of the bottom. The resistance of the bottom of the bottle to puncture efforts, in the case of a stacked and spliced load, is greatly increased. As a result, the stability of the stacked and spliced load is improved. The resistance to the retention of the bottle, during storage, is also improved, without observing any deformation of smoothing (inclination in relation to the vertical) after a storage of 7 days at 40 ° C. In addition, no background break was observed in vertical drop tests from a height of one meter (bottles made of PET filled with calm water and hermetically sealed).

In the embodiment of Figures 4 and 5, the bottle has a substantially rectangular cross section, having convex curved sides, and its bottom 20 has a curved contour which is substantially rectangular, being defined by two long convex sides 50 and two sides short convexes 52, interconnected by convex circular arcs or round portions 54. As noted above, the bottom 20 comprises a concave, meshed central portion, 26, which is connected via a flat annular surface 28 with a convex peripheral surface 30 for stopping about a support surface, and radial ribs 38, regularly spaced apart, formed on said convex surface 30. As can be clearly seen in Figure 5, the radial grooves 38 are formed along the diagonals 56 of the bottom 20. The number of Slots are advantageously on the scale of 12 to 16 (14 in the example shown), and can be on the scale of 8 to 20 or 10 to 20, as a function of the shape and size of the fund. On the other hand, the characteristics of the bottom of the bottle of Figures 4 and 5 are the same as those already described for the bottle of Figures 1 to 3. Figure 6 is a diagrammatic fragmentary view in axial section of a mold for making a bottle of the invention, such as a bottle of Figures 1 to 3. The mold 60 comprises a bottom wall 62 having an internal face comprising a central surface 64, convex, projecting, shaped, a concave peripheral surface 66 including radial ribs 68, regularly spaced, and an annular surface 70 substantially planar, which connects the convex central surface 64 with the concave peripheral surface 66, the concave peripheral surface 66 connecting with the internal peripheral face 72 of the mold. The shapes of the inner face of the bottom of the mold correspond to the bottom shapes of the bottle of Figures 1 to 3 with inverted curvature, the concave surfaces of the bottom of the mold corresponding to the convex surfaces of the bottom of the bottle, and vice versa , and the radial ribs 68 of the bottom of the mold corresponding to the radial grooves 38 of the bottom of the bottle.

Claims

1. - A molded plastic bottle, comprising a neck (12) designed to receive an upper part (14), a lateral wall (18) substantially cylindrical, and a bottom (29) formed with a concave or meshed central portion (26) and a convex peripheral surface (30), which includes radial grooves (38) and which is connected to the concave central portion (26) of the bottom via a substantially flat annular surface (28), the bottle is characterized in that the bottom ( 44) of each radial slot (38) connects substantially and tangentially with said planar annular surface (28).

2. A bottle according to claim 1, characterized in that the radial width of said flat annular surface (28) is greater than the radius of the concave central portion (26) of the bottom.

3. A bottle according to claim 1 or 2, characterized in that the diameter of the concave central portion (26) of the bottom is smaller than the diameter of the upper part (14) for screwing around the neck of the bottle.

4. A bottle according to any of the preceding claims, characterized in that the convex peripheral surface (30) of the bottom is connected to the flat annular surface (28) via a concave annular surface (34).

5. A bottle according to any of the preceding claims, characterized in that the convex peripheral surface (30) of the bottom is connected to the side wall (18) via a convex cylindrical surface (36), whose generating line is a circular arc which has a large radius of curvature.

6. A bottle according to any of the preceding claims, characterized in that the bottom (44) of each radial groove 38 formed in the convex peripheral surface (30) is tangentially connected to the connector surface (34) between the flat annular surface (28) of the bottom and the convex peripheral surface (30).

7. A bottle according to any of the preceding claims, characterized in that the bottom (44) of each radial slot (38) is connected to the side wall (18, 36) of the bottle via a convex surface followed by a concave surface

8. A bottle according to any of the preceding claims, characterized in that the radial grooves (38) have a V-shaped cross section.

9. A bottle according to any of the preceding claims, characterized in that the profile of the bottom (44) of each radial groove (38) comprises a convex circular arc connecting via a concave circular arc with the flat annular surface (28) of the bottom of the bottle and via a convex circular arc followed by a concave circular arc with the wall side of the bottle.

10 -. 10 - A bottle according to any of the preceding claims, characterized in that its bottom (20) has a circular contour and the number of radial grooves (38) is on the scale of 6 to 20, and in particular is 9, 10 u 1 1. 1 1 .- A bottle according to any of claims 1 to 9, characterized in that its bottom (20) has a substantially polygonal outline, eg. , square or rectangular, and comprises radial slots (38) uniformly spaced. 12. A bottle according to claim 1, characterized in that the radial grooves (38) extend along the diagonals (56) of the bottom. 13. A bottle according to claim 1 or 12, characterized in that the number of radial grooves (38) is on the scale of 8 to 20 or 10 to 20, and in particular on the scale of 12 to 16 14. A bottle according to any of the preceding claims, characterized in that, when full, said flat annular surface (28) remains at an axial distance (d) substantially equal from the bottom of the convex peripheral surface (30) like when the bottle is empty. 15 - A mold for making a bottle according to any of the preceding claims, comprising a lower wall (62) formed with a central convex or projecting surface (64), a concave peripheral surface (66), including radial ribs (68) and a flat annular surface (70) connecting the central surface ( 64) to the concave peripheral surface (66), the mold being characterized in that the upper part of the radial ribs (68) is substantially and tangentially connected with said flat annular surface (70).