MXPA99005813A - Multichamber container with expanded interior walls - Google Patents

Abstract

Multichamber tubular containers (50) are made by extrusion or injection stretch blow molding. The containers usually will have two or three chambers and one or more web walls (42). The web walls are relatively rigid as formed. The web walls (42) must be stretched laterally to increase their flexibility which is needed for the uniform dispensing of product from the tubular chambers. The webs (42) can be stretched mechanically by the rotation of rods (46), such as stretch rods, or pneumatically by a differential gas pressure in the chambers while the webs (42) are at or near the glass transition temperature and can flow. The web walls for a circular tubular container can be stretched up to about one-half the diameter of the tubular container.

Description

CONTAINER OF MULTIPLE CAMERAS WITH EXPANDED INTERIOR WALLS FIELD OF THE INVENTION This invention relates to the molding of multi-chamber containers of more uniform assortment. More particularly, this invention relates to the blow-molding of containers with multiple chambers with laterally expanded inner woven walls to provide a more uniform supply of products from each of the chambers of the containers.

BACKGROUND OF THE INVENTION This invention is directed to container extensively and to tubular containers as one of the preferred embodiments. The highly flexible internal woven walls are very useful in the construction of tubular containers that will have uniform assortment properties. This allows an assortment force applied to the outer surface to be more uniformly received by the materials within the various chambers of the container.

Tubular containers are used to supply a number of products. These include food products, oral care products and personal care products. These are particularly useful in the assortment for products for personal care and oral care. These products are viscous materials such as lotions, pastes or gels. The tubular containers that are currently used are tubular single-chamber vessels primarily and span a range of materials and a number of manufacturing techniques. The tubes comprise metal tubes, multi-layer laminated tubes, extruded tubes and blow molded tubes. Metal tubes are usually collapsible aluminum tubes. Laminated multilayer pipes may be composed only of polymer layers or may contain paper and other layers of sheet metal. The paper layer can be a printed layer and a metal sheet layer would be a barrier layer, as well as a layer that produces a collapsible tube. The extruded tubes can be made from a continuously extruded tube that is cut to the desired lengths. This can be single-layer or multi-layer plastic construction.

In most laminated tubes or extruded tubes, the tube body is produced separately from the shoulder of the tube and the nozzle. The shoulder and nozzle of the tube can be injection molded and then joined on the body of the tube. If they are not thus formed and joined in the tube body, they can be molded by compression in the tube body. In this technique, the nozzle and the shoulder are formed at the same time as they are joined on the tube body.

The blow molded tubes are currently produced in a single chamber shape, by an extrusion blow molded technique. In this technique, the materials are extruded in a tubular form, placed in a mold that is of the desired tube shape, and a gas, such as air, is blown into the extrusion to form extrusion to the mold shape. The tube is then taken from the mold, has a fully formed shoulder and nozzle, as well as a side wall. The bottom end can also be closed. The tubular container can be filled by the top or the bottom end can then be cut so that the tub can be filled with product from the bottom and the bottom sealed. In contrast to multiple layer laminated tubes and extruded tubes, these blow molded tubes are produced in a finished form. It is not required in additional training such as a shoulder and nozzle connection. However, the blow molded tubes of this invention are also an improvement over the blow molded tubes currently used, since these can be produced to have a plurality of cameras and dividing walls that are highly flexible.

A preferred blow molded tubular container, recently developed by the inventor and others, produces blow-molded stretch-blow molding. These tubular containers with superior resistance and sweeping properties by means of the plastic being biaxially oriented have improved the strength for a given thickness. This injection stretch blow molding can be of a monolayer or multi-layer construction or can be of a single chamber or multiple chamber construction.

In the various techniques for producing multi-chamber tubular containers there is a need to increase the lateral dimension of the interior tissue walls. These are the walls that stop the tubular container in a plurality of chambers. The tissue walls are increased in the lateral dimensions for several reasons. One reason is to reduce the stiffness of tissue walls. Another reason is to assist in the formation of a lower crimping seal when the tubular container is filled by the bottom and then sealed with crimping. Another reason is that the fabric wall with an increased side dimension provides greater flexibility of the fabric walls, which in turn results in a more uniform assortment of the materials from the tubular container chamber.

In the present invention, the tubular containers can be essentially of any shape. The lateral dimension of the inner fabric walls has been modified by laterally moving the rods, such as the stretching rods, in each chamber, while the tissue walls are in a heated condition so that the separating fabric walls are reformed to a differential side width as described in the United States of America Patent No. 2,951,264. Japanese Patent No. 5,254.00 discloses that a multi-segmented container can be blow molded. This further discloses that the different segments of this multi-segmented container may have different thickness depending on the amount of expansion of the pre-form during the blow molding process. However, this reform of the fabric walls to a different side width can be better achieved through the use of a differential gas pressure in one or more of the chambers. In the latter technique, this is done while the plastic is in the range of the glass transition temperature and can flow using an applied force. Also the cameras can be essentially of any number, size and layout. By expanding the width of the fabrics, the fabrics become less rigid and more flexible and provide a more uniform assortment from the containers.

The processes of the present invention solve problems of how to produce useful chamber vessels that have more uniform assortment properties, increased strength, less rigid and relatively thin tissue walls, and decreased return suction of air and product back into the tube. after the assortment. S provides a method for increasing the lateral dimension of the inner tissue of the container at the time when the containers are being produced or at a later time. These techniques are particularly useful for tubes produced by extrusion blow molding and blow-stretch injection molding techniques. E each of these techniques the woven walls are initially produced from the lateral dimension of the container. These tissue walls must be stretched to gain the properties and advantages described above.

Brief Summary of the Invention In the production of multi-chamber containers are blow molded, the interior woven walls of the chambers have limited flexibility. The lateral dimension of these tissue walls is essentially the diameter or the lateral dimension related to the container. In order to provide a more uniform assortment, the lateral dimension of the tissue edges should increase. This decreases the stiffness of the interior tissue walls and increases the flexibility of these tissue walls. This also helps in the formation of curling seals in tubular containers where the tissue wall will be inside the curling seal. The techniques of this invention can be effectively used to increase the lateral dimension of tissue walls produced by any technique. NeverthelessThese techniques are very useful when multi-chamber containers are produced by blow-molding and particularly when they are produced by blow-molding, drawn by injection. In these blow molding processes, a preform is cast by extrusion or injection. This pre-form will have the same number of cameras as the final container. This pre-forms and heated to around the transition temperature of the plastic glass and is placed in a mold having the desired shape of the container. A gas such as air is blown into the vessel to form a preform for the shape of the mold. For the extrusion blowing molding a gas, such as the air is blown into the open end of the preform is extruded to form this preform to the shape of the mold. For the stretch blow molding with injection, the stretching rods are placed in each chamber and a gas or fluid and injected as the stretching rods move downward to longitudinally stretch the tube preform while blowing the pre-form. tube shape laterally to the final tube shape. In a preferred embodiment, the tubular container forms with the finished shoulder and neck, fully formed and in place.

The tubular containers will usually be formed with a sufficiently large dispensing opening so that they can also be filled through this opening. However, as an option, the bottom can optionally be cut from the tubular container, if necessary and the tubular container then filled. This tubular container after having been filled from the bottom is then sealed curled. The top filling is preferred since it will retain more of the strength of the tubular container.

A method for laterally stretching the separating tissue walls of the multiple chambers of the tube by moving the rods, such as the stretching rods, laterally while the plastic of the inner walls is at a temperature at or near the temperature of the walls. transitioned from glass and in a flowable condition. This will stretch the inner fabric walls that are in contact with the rods to a larger lateral dimension than they were. This will reduce the stiffness of the fabric walls and increase the flexibility of the tissue walls. The lateral dimension of the inner woven wall can be measured with up to about one half of the circumference for a tubular container. However, it will primarily provide better control of the assortment of substances from multiple chambers.

Another additional option is to laterally stretch the tube walls by changing the pressure in at least one chamber during or after the time when the tubular container has been blown into its shape. This is useful when the container is formed by blow molding and can be achieved by increasing or decreasing the pressure in the blowing gas in a chamber during or after blowing in a chamber during or after blowing while the plastic in the chamber is blown. Woven walls are in a flowable condition. This will increase the lateral dimension of the tissue walls and result in a more flexible tissue wall and better control of the substance assortment from each chamber of the tubular container. Preferably, there are rods in the chambers by the pressure difference step to assist in the lateral stretching of the tissue walls.

This invention solves the problems of producing multi-chamber tubular containers, and in particular, blow molded tubular containers having improved control in the assortment of each of the chambers. This is solved by providing dividing fabric walls which have greater flexibility by having a larger lateral dimension than that of the tubular container. The greater flexibility of the interior fabric walls provides a more even distribution of an assortment force applied through the container.

Brief Description of the Drawings Figure 1 is a schematic diagram of the top fill embodiments of the present invention.

Figure 2 is a cross-sectional view of a shape for a multi-chamber container.

Figure 3 is a cross-sectional view of another form for a multi-chamber container.

Figure 4 is a cross-sectional view of a three chambered multi-chamber tubular container.

Figure 5 is a cross-sectional view of a tubular container of two-chamber multiple chambers with the tissue wall offset in the tubular chamber.

Figure 6 is an elevated view of a fabric being laterally stretched by the rods.

Figure 7 is a cross-sectional view of a tubular container of Figure 5.

Figure 8 is an elevated view of a tissue that has been stretched laterally through gas pressure.

Figure 9 is a cross-sectional view of a tubular container of Figure 10.

Figure 10 is a transverse sectional view of a tubular dual chamber container.

Figure 11 is a cross-sectional view of the three chambers.

Detailed description of the invention This invention will be described in greater detail with reference to the drawings. When not restricted to tubular containers, it will be described with reference to tubular containers as a preferred embodiment. Figure 1 schematically established the process for making blow molded tubulare containers. The first step is to mold the preform. This is usually extruded or molded by injection. If it is not inside a mold, the pre-form at about the transition temperature of the glass is then placed in a mold where the inner surface of the mold has the shape of the tubular container to be molded. A gas is then injected to stretch the preforms to the walls of the mold. If the preform is going to be blow molded with injection, insert one or more stretching rods into the preform. Usually, there will be at least one stretching rod in each chamber for a tubular multi-chamber vessel. When the preform is at a temperature where the plastic is around the transition temperature of the glass, the stretching rods move downward to stretch the plastic longitudinally. At a suitable time, a gas, just as air flows under pressure inside the preform. This gas pressure forces the walls of the pre-form laterally until they make contact with the interior surface of the mold. This cold mold surface cools the plastic so that it maintains this shape. The mold will usually be maintained at a certain temperature range by means of a heat transfer fluid that is fluid through the mold. Molding will occur at around the transition temperature of the resin glass.

As described during blow molding the plastic will be close to the flow point under the blowing pressure. This is usually around the glass transition temperature. The pre-form if it is not in a heated condition will be heated to around the transition temperature of the glass before being put into the mold. The gas pressure during blow molding will vary from about 10 bars to about 40 bars and preferably from about 12 bars to about 20 bars. The tubes are produced at a blowing rate of about 10 to 20. The tubular container is then removed from the mold. The walls are stretched laterally as described here. The tube is then filled and a lid is placed over the filling and assortment opening.

Embodiments A and B of the invention in Figure 1 are directed to tubular multi-chamber vessels wherein the interior fabric divider walls are stretched to increase the lateral dimension of the interior divider fabrics. This is preferable for sealed containers with curling, since the fabric or fabric separating chamber in the curling should be wider than the diameter of the tubular container when the tissue wall will be located longitudinally in the curling seal. This also provides more flexible and less rigid separating fabric walls, which in turn provide better control over the assortment. There will be a more uniform assortment. The separating fabric walls are mechanically stretched by means of the lateral movement of the rods after the tubular container has been formed 0 by differential pressure in the chambers when the tubular container is being formed or after the tubular container has been formed. These processes are established in the Figure 1 as incorporation ÍA and incorporation IB, respectively.

In the embodiment A of figure 1 and figure 2, the rods, which can be stretching rods, are rotated by the rotation of the head piece that holds the rods. However, the mold can be rotated and the rods kept stationary. This causes the tissue wall. This causes the separating tissue wall to stretch laterally. This is described in greater detail in Figures 10 and 11. In embodiment IB and 2B of Figure 1, during just after the molding formation with container blowing, a differential pressure is made in one more of the chambers. This will cause a dividing fabric wall where there is a differential pressure to stretch in the lowered pressure chamber. A differential pressure of more d around a bar, and preferably of more than about d 3 bars is advantageously used. However, higher and lower differential pressures can be used. After the fabric walls have been formed to the desired side dimension, the bottom is cut off in the case when the bottom is to be filled when a larger filling opening is to be provided. The filled chamber and the bottom are sealed with curling. When the tubular container is to be filled by the upper part, the tubular container is filled and the lid is placed in place to seal the tubular container.

Figures 2 and 3 show two different cross sections for the tubular containers 20. These containers have a dividing fabric wall 22. They may be round, Figure 2 or elliptical as in Figure 3. However, the containers may be of many sizes. others different way There is no real limitation as to the shape of the container.

Figure 4 shows a container with three chambers. The container 30 has the inner tissue walls 36 and 38. Figure 5 shows the incorporation of the container 30 with an off-center tissue wall 34.

Figures 6 and 7 describe the stretching of the tissue wall of a dual chamber container 50. Here, the stretching is by the mechanical action of the lateral rotation of the rods, such as the stretching rods. This will be done while the plastic is at or near the transition temperature of the glass. This rotation of the rods 46 causes the plastic of the dividing fabric wall 42 to stretch laterally. The effect of this stretch is shown in Figure 7. This can be carried out when the tube is blown or after the tube has been blown. It is preferred to rotate the stretching rods immediately after the tube has been blown, but while the tube is in the mold 48.

Figure 8 depicts the lateral stretching of the chamber divider tissue wall or the tissue walls by a differential pressure. Here there is a single dividing fabric wall 42 but the technique is applicable to a plurality of tissue walls. In this embodiment IB and 2B, the gas pressure in the chamber 54 will be greater than the chamber 56. This causes the tissue wall 42 to stretch towards and around the rod 46 that is in the chamber 56. Even though it is not In many cases it is preferred to maintain a rod at least one lower pressure chamber to assist in the lateral stretching of the tissue wall. This rod will hold the tissue wall will allow an increased lateral stretch of the tissue wall. This is shown in greater detail in Figure 9. This differential gas pressure can be achieved by increasing the pressure in the chamber 54 or by lowering the pressure in the chamber 56. The result will be essentially the same. In the embodiment 2B the bottom end is then cut off and the tubular container is inverted for filling. After filling it is sealed and curled. This lateral stretching is carried out while the plastic is heated at or near the transition temperature of the glass and is mouldable. This can be done while the container is being blown or after the container is blown. It is preferred that this be done immediately after the tube is blown and while the plastic is still being heated. Figures 10 and 11 show stretched tissue walls placed through the containers.

In Figure 10, the tissue wall 42 is shown in a laterally extended and flexible position in the tubular container 50. The volume of the chambers 54 and 56 may vary depending on the amount of product to be filled that is filled in each camera. In Figure 11 a tubular container 60 is shown having 3 chambers created by two tissue walls. The fabric wall 68 separates the chambers 62 and 66 and the tissue wall 70 separates the chambers 64 and 66. The walls 68 70 have been extended by laterally stretching the fabric walls after the tubular container has been blow molded. When molding with blow, the tissue walls will be placed through the tubular container as shown in Figure 4.

The processes for the lateral stretching of the walls of woven chamber dividers have been described as part of the process for making the container by co-blowing molding. However, containers can be produced by other than blow molding and the tissue walls can be stretched laterally at a later time. It will only be necessary to heat the fabric walls to around the transition temperature of the plastic glass and laterally stretch the plastic mechanically in a unique way through the use of the rotation of the rods or through the use of a differential pressure with or without the use of rods When the rod or rods are rotated through the rotation of the head piece that holds the rod or rods, the tissue stop is stretched laterally. Similarly, when there is a sufficient differential gas pressure on any side of the tissue wall, the tissue wall will stretch laterally. This can be caused by increasing the pressure on one side of the tissue wall or by decreasing the pressure on the other side of the tissue wall.

As noted, the use of a laterally elongated fabric provides a very flexible barrier that improves the uniform delivery of products from different chambers of the tubular container. The fabric walls are less rigid and more flexible. This also allows the fabric to be aligned in the ripple in the crimped sealed tubes. In this way, a more uniform thickness is being sealed. In this last aspect, the tissue wall for a dual chamber tube will preferably be about one half the circumference for the round tubular containers. This will be around 1 / 2pd where d is the diameter of the tube. However, depending on the number of tissue walls and their location in the container, these can be of various lengths when stretched laterally.

The blow molded tubular containers of this invention have high strength and uniform assortment properties. Tubular containers can be made of any materials that can be blown and stretched. Preferred materials are polyethylene terephthalate, polyethylene naphthanate, modified polyethylene terephthalate, modified polyethylene naphthanate, mixtures of these polyesters and polypropylene. The fluid used for blow molding the tubular containers will usually be air dried, however, other fluids such as nitrogen, carbon dioxide or various inert gases or fluids may be used.

The molds, the rods and the stretching rods and other equipment used in the process are standard in commerce. No special or particular equipment is required. The advantages of the tubular containers present will be achieved by the following described processes.

The techniques that are described are very useful to increase the lateral dimension of the tissue walls? tubular containers with multiple chambers. These techniques can be modified to various degrees, however, all these modifications are within the concepts of the techniques described.

Claims (9)

R E I V I N D I C A C I O N S

1. A method for making containers having a plurality of longitudinally located chambers comprising: (a) forming a preform of said container, said preform having at least one inner tissue wall separating a plurality of longitudinally positioned chambers, said at least one inner tissue wall extending from one end to the other end of said pre-form. (b) placing said preform into a mold and stretching said preform at least by blowing a ga inside said preform to form a container having the shape of said mold, said container having at least a wall of inner fabric separating said plurality of longitudinally positioned chambers, an opening opening at one end and having another closed end, said at least one interior tissue wall extending from one end to said other end of the container; Y (c) characterized in that a differential gas pressure is provided in at least one of said plurality of chambers with respect to each other of said plurality of chambers to increase the lateral dimension of said at least one inner wall to a larger dimension that said one said at least one interior tissue wall with the formation of said container.

2. The method as claimed in clause 1, characterized in that said container is a tubular container.

3. The method as claimed in clause 1, characterized in that each chamber of said pre-form is stretched longitudinally as the gas is blown into the pre-form.

4. A method as claimed in clause 3, characterized in that said stretching of the longitudinal length is achieved by means of at least one stretching rod that extends inside each chamber of said preform, at least one stretching rod. It moves longitudinally to stretch said preform.

5. A method as claimed in clause 4, characterized in that the lateral dimension of at least one woven wall is elongated while in a heated condition.

6. A method as claimed in clause 5, characterized in that after blowing a gas into said preform to form said preform in said container, a differential gas pressure is formed from one chamber to the other chamber to increasing the lateral dimension d said at least one wall of inner fabric by e stretching said at least one wall of inner fabric.

7. A method as claimed in clause 6, characterized in that there are at least two chambers, the gas pressure in one of said chambers is different from the gas pressure in another of the chambers to thereby increase the lateral dimension of the gas. said at least one interior woven wall.

8. A method as claimed in clause 5, characterized in that during the period of the differential gas pressure there is at least one rod in a chamber d a lower differential gas pressure.

9. A method as claimed in clause 8, characterized in that said container is a tubular container. E S U M N Tubular multi-chamber vessels are made by extrusion or stretch blow molding with injection. The containers will usually have two or three chambers and one or more tissue walls. The tissue walls are relatively rigid when formed. The fabric walls must be stretched laterally to increase their flexibility which is necessary for the uniform assortment of the product from the tubular chambers. The fabrics can be stretched mechanically by the rotation of the rods, such as the stretching rods or pneumatically by means of a differential gas pressure in the chambers while the tissues are at or near the glass transition temperature and can flow . The tissue walls for a circular tubular container can be stretched to about one half the diameter of the tubular container.