MXPA99006587A - Method for making tubular containers - Google Patents

Abstract

In the manufacture of multichamber tubular containers it has been found that the inner divider walls (12) should be bonded to the exterior wall (10) by means of a band sealing method. In the band sealing method there is a band (30) that contacts the upper film and a band (32) that contacts the lower film that are to be bonded. In the present processes the upper band contacts the inner divider wall while the lower band contacts the exterior surface of the outer wall of the tubular container. In order to prevent the marring or otherwise putting a defect into the exterior surface of the outer wall the temperature of the lower band is maintained at a lower temperature than the upper band. This will decrease the temperature of the exterior surface of the outer wall and prevent imperfections in the exterior surface of the outer wall. The advantage is a multichamber tubular container without any imperfections in the exterior surface. This enhances the overall appearance of the tubularcontainer.

Description

METHOD FOR MAKING TUBULAR CONTAINERS FIELD OF THE INVENTION This invention relates to a method for joining inner walls to with tubular containers. More particularly, this invention relates to a method for attaching the interior divider walls to a tubular container to produce a multi-chamber tubular container.

-ANTAINING OF THE INVENTION There are several techniques for making multi-chamber tubular containers. The present invention is directed to multi-chamber tubular containers wherein each chamber makes contact with the upper wall of the tubular container and extends longitudinally from the nozzle outlet to the base of the tubular container. This is with distinction to the containers "tube in a tube" where the different chambers are located concentrically. It has been found that the arrangement in which each chamber is in contact with the tube wall, for example, with the tube wall that forms a part of each tubular chamber, provides better control over the assortment of the contents from the tubular vessel. . There can be a more uniform assortment of the contents of each chamber in the construction of a multi-chamber tubular container.

One problem that has been encountered in the manufacture of these multi-chamber tubular containers is the joining of the inner dividing walls on the tubular container wall. In one method the inner wall or inner walls are joined to the tube wall before the tube is formed by joining two longitudinal edges of the dividing wall to the outer wall. In this technique the inner wall is superimposed on the outer tubular container wall, each in a flat room. The two longitudinal edges of the interior divider wall are then attached to the inner surface of the outer tubular container wall. With the longitudinal edges of the outer wall being joined together to form a tubular container a tubular container with two chambers is formed. This tubular container can be of three or more chambers if there are additional interior walls. A problem that arises in the formation of these tubular containers is the joining of the interior divider walls to the outer tube wall. There must be a strong runoff test seal, but notwithstanding this, one where there is no scratching otherwise imperfections are placed on the outer surface of the outer tubular wall. Any imperfections will cause a perceptible imperfection in the decoration of the tube. Such imperfections are not acceptable since they affect the impression of the product by the potential buyer. The product seems to be damaged.

Various techniques have been tried in order to obtain a strong seal of the interior divider walls to the inner surface of the outer tubular container wall. A conventional heat seal formed by a heated plate surface on the inner dividing wall has the problem that the dividing wall is susceptible to sticking to the heated plate surface. Similarly, the ultrasonic seal was found to be ineffective in forming strong seals since the thinner interior divider wall is susceptible to damage during the application of ultrasonic energy. The only technique that was found to be highly effective at producing strong seals at commercially feasible speeds without imperfections on the outer surface of the outer wall is the use of a sealing band technique where the web is in contact with the outer surface of the outer wall. The outer wall is maintained at a lower temperature than that of the band that is in contact with the surface of the dividing wall. This results in strong seals without imperfections on the outer surface of the outer wall.

Band sealants customarily have two rotating bands. One band makes contact with the outer surface of a material to be joined and the other band makes contact with the outer surface of the other material. In this case, one material is the chamber divider wall and the other material is the outer tubular container wall. The bands can be metallic, ceramic or plastic material.

Woven glass fiber bands coated with polytetrafluoroethylene (PTFE) have been found to be very effective. Polytetrafluoroethylene is stable at elevated temperatures and has a very lubricious surface. This will not adhere to the materials with which it makes contact. The present invention is directed to the use of a band sealant wherein the band is in contact with the outer surface of the outer wall and is maintained at a reduced temperature. This technique solves the problem of producing strong seals at commercially feasible speeds without imperfections in the outer surface of the outer wall of the container.

BRIEF SUMMARY OF THE INVENTION The present invention is directed to a method for securing the interior divider walls to the interior surface of the exterior wall of a container by means of the use of a band sealing technique. In the band sealing technique said one band makes contact with the surface of the inner divider wall and the other band makes contact with the outer surface of the outer wall. The band that contacts the surface of the interior divider wall is at a temperature higher than that of the band that contacts the exterior surface of the exterior wall. The band that contacts the surface of the interior divider wall will be around the sealing temperature of the plastic of the interior divider wall above it. This is a temperature sufficient to raise the temperature of the plastics to be bonded around the melting temperature to about 15 ° C below the melting temperature. The contact time will be about 0.05 to 20 seconds, and preferably about 0.1 to 10 seconds. The contact pressure of the strip with the plastic films will be from about 0.1 kg / cm2 to about 7 kg / cm2 and preferably from about 0.25 kg / cm2 to about 4 kg / cm2.

A key feature in the process is that the web in contact with the interior divider wall is at a temperature of at least about 25 ° C to about 200 ° C, and preferably at least about 50 ° C. C at about 150 ° C above that of the band that is in contact with the outer surface of the outer wall. In this way the band in contact with the outer wall absorbs the heat that is applied by the other band keeping the outer surface of the outer wall at a temperature below that at which the heat can cause surface imperfections. After the seal is made, the seal is cooled by an air flow or by contact with a cooled band.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows an interior divider wall lying on the outer wall before joining.

Figure 2 schematically shows a band sealer.

Figure 3 shows a tubular container in section with the interior divider wall.

DETAILED DESCRIPTION OF THE INVENTION The invention is directed to producing strong seals at commercially feasible rates without imperfections in the outer surface of the plastic of the outer wall. This is achieved through the use of a band sealer.

In Figure 1 there is shown an interior divider wall 12 lying on an outer wall 10. The longitudinal edges 18 and 20 of the interior divider wall are to be sealed to the exterior wall along the longitudinal edges. This is achieved by the use of the belt sealing device of Figure 2. The belt sealant consists of the belts 30 and 32. The belt 30 is supported by the pulley wheels 34 and 36 and the belt 32 is supported by the wheels. of pulley 38 and 40. Heating block 31 heats band 30 and heater block 33 heats band 32. These heaters are independently adjustable, each heating a particular band. Each heating block is in contact with the respective band with the contact pressure being adjustable. The pinch wheels 35 (a) and 35 (b) apply a pressure to the film between the band 30 and the band 32. These pinch wheels are adjustable so that the applied pressure can be adjusted.

The cooling blocks 42 and 44 cool the bands 30 and 32 and the seal areas as the lamination seal passes through this part of the band sealant. Each cooling block is in contact with the respective band with the contact pressure being adjustable. All these bands make contact with the seal area and not with the complete layers 10 and 12. The layers that are to be sealed at the seal manufacturing point are passed through the band sealant. The heaters are adjusted to provide a strong seal but not to provide imperfections in the outer surface of the outer layer. As shown, the outer layer 10 is the lowermost layer and the inner divider layer 12 rests on this layer 10. The heater 31 is adjusted to a temperature higher than that of the heater 33. The pressure forming the seal is adjusted by force of the pressure wheels 35 (a) and 35 (b) against one another and the heating blocks against their respective bands. The heater 31 will be at a temperature to maintain the strip 30 at least about 25 ° C to about 200 ° C above that of the strip 32 which is heated by the heater 33 and preferably around 50 ° C to about 150 ° C. In a preferred mode the heater 33 is at room temperature, that is, the heater 33 is in an off state with the heat of sealing provided only by the heater 31. The heater 31 applies heat to the interior divider wall by means of the heater band 30. In this manner the heat is not applied directly to the outer surface of the outer wall 10. However, the band 33 will be heated through contact with the outer layer 10 which is the outer surface of the tubular container wall.

The pressure wheels 35 (a) and 35 (b) are set at a pressure of about 0.1 kg / cm2 to about 7 kg / cm2, and preferably around 0.25 kg / cm2 to about 4 kg / cm2. Similarly, heater blocks 31 and 33 and cooling blocks 42 and 44 lie against their respective bands at about the same pressures as the pressure wheels. The pressure of the heating blocks, the pressure wheels and the cooling blocks can be the same or different. These pressures force the softened plastic layers together to produce a stronger seal joint. In the final band sealing step, the sealed layers pass through the cooling blocks.

The inner divider layer and the outer plastic layer to be joined can be any thermoplastic material. These include polyolefins such as polyethylene, polypropylenes and polybutadienes; copolymers of ethylene with vinyl compounds such as vinyl alcohol and vinyl acetate; acrylononeutulebutadienes-styrenes; and polyesters such as polyethylene terephthalate. The thickness of the outer wall can vary from about 0.2 millimeters to 0.5 millimeters. The inner divider layer will generally have a thickness of less than the outer layer. The interior divider wall will have a thickness of about .015 millimeters to about 0.2 millimeters.

Figure 3 is a partially sectioned view of a tubular container having an outer wall 10 and an inner wall 12. The inner wall is attached to the outer wall 10 at the edge 18 and at the edge 20. The seal is around from 1 millimeter to about 5 millimeters or more in width. The seal is continuous, has superior strength and the outer surfaces of the outer wall 10 are smooth without imperfections. The lower curl seal 22 seals the bottom of the tube. The upper part has an attached nozzle.

The foregoing establishes the preferred embodiments of the processes for sealing an interior divider wall to an exterior wall. Any modifications which incorporate the techniques described herein will be considered to be within the present invention.

Claims (15)

1. - A method for making tubular multi-chamber vessels comprising overlaying at least a second film on a first film and sealing the longitudinal edges of said second film to said first film, contacting the longitudinal edges of said first film and sealing said longitudinal edges of said first film together to form a tubular body, and fastening an outlet nozzle to one end of the tubular body, the improvement comprising sealing the longitudinal edges of said second film on said first film by means of a band of sealing, a band in contact with said first film being at a lower temperature than a band in contact with said second film.

2. - A method as claimed in clause 1 characterized in that the band in contact with said first film is at a temperature of about 25 ° C to about 200 ° C less than the band in contact with said second film.

3. - A method as claimed in clause 2 characterized in that the band in contact with said first film is at a temperature of about 50 ° C to about 150 ° C less than the band in contact with said second film.

4. - A method as claimed in clause 1 characterized in that said first film and said second film are composed of at least one layer of a polyolefin.

5. - A method as claimed in clause 1 characterized in that said polyolefin is selected from the group consisting of polyethylene, polypropylenes, polybutadienes, ethylene vinyl alcohol copolymers, ethylene vinyl acetate, acrylonitrile-butadiene-styrenes copolymers, and polyesters and mixtures thereof.

6. - A method as claimed in clause 1 characterized in that said first film has a thickness of about 0.2 millimeters to about 0.5 millimeters and said second film has a thickness of about 0.015 millimeters to about 0.2 millimeters.

7. - A method as claimed in clause 1 characterized in that during at least part of the sealing time of the longitudinal edges of said second film on said first film a pressure is applied to said first film and said second film to place said first film and said second film in a more intimate contact.

8. - A method as claimed in clause 7 characterized in that said pressure is from about 0.1 kg / cm2 to about 7 kg / cm2.

9. - A method for making tubular multi-chamber vessels comprising overlaying at least a second film on a first film and sealing the longitudinal edges of said second film to said first film, contacting the longitudinal edges of said first film and sealing said longitudinal edges of said first film together to form a tubular body, and fastening an outlet nozzle to one end of the tubular body, the improved component comprises sealing the longitudinal edges of said second film on said first film by means of band sealing , a band in contact with said first film being at a temperature of about 25 ° C to about 200 ° C lower than a band in contact with said second film.

10. - A method as claimed in clause 9 characterized in that the band in contact with said first film is at a temperature of about 50 ° C to about 150 ° C less than the band in contact with said first film.

11. - A method as claimed in clause 9 characterized in that said first film and said second film are composed of at least one layer of a polyolefin.

12. - A method as claimed in clause 9 characterized in that said polyolefin is selected from the group consisting of polyethylene, polypropylenes and polybutadienes, ethylene vinyl alcohol copolymers, ethylene vinyl acetate, acrylonitrile-butadiene-styrenes copolymers, polyesters and mixtures thereof.

13. - A method as claimed in clause 9 characterized in that said first film has a thickness of about 0.2 millimeters to about 0.5 millimeters and said second film has a thickness of about 0.015 millimeters to about 0.2 millimeters.

14. - A method as claimed in clause 9 characterized in that during at least part of the time of sealing the longitudinal edges of said second film on said first film a pressure is applied to said first film and said second film to place said first film and said second film in a more intimate contact.

15. - Such a method - and as claimed in clause 14 characterized in that said pressure is about 0.1 kg / cm2 to about 7 kg / cm2. ABSTRACT In the manufacture of tubular multi-chamber containers it has been found that the interior divider walls must be joined to the outer wall by means of a band sealing method. In the band sealing method there is a band that makes contact with the upper film and a band that makes contact with the lower film that are to be joined. In the present process the upper band makes contact with the inner divider wall while the lower band makes contact with the outer surface of the outer wall of the tubular container. In order to avoid scratching or otherwise to put a defect on the outer surface of the outer wall the temperature of the lower band is maintained at a lower temperature than that of the upper band. This will lower the temperature of the exterior surface of the exterior wall and avoid imperfections in the exterior surface of the exterior wall. The advantage is a tubular container of multiple chambers without any imperfections in the outer surface. This improves the overall appearance of the tubular container.