Device for accomplishing at least a liquid tight joint and a method for manufacturing such a device

A device and a method for forming at least a liquid tight joint between two elements. Either or both elements have sealing portions, which in an area intended for abutment of the elements provide said joint when said elements are brought together in the abutment area. The sealing portion is formed as a seal which by being formed by sequential injection moulding technique is molecularly integral with an area directly adjacent to said seal. The injection moulding technique allows a choice of a relatively softer material for the sealing portion and a high degree of design freedom, including designs of high hygiene standards, especially well suited for aseptic or sterile packaging systems.

FIELD OF THE INVENTION 
The present invention relates to sealing devices and more precisely to 
seals of the type which are able to provide at least a liquid tight joint 
between two elements. Such a joint may be used for instance when 
interconnecting pipes or pipe studs or when terminating a certain pipe 
length. 
The invention is especially applicable at manufacturing techniques where it 
is desirable to allow a high degree of design flexibility and a wide 
choise of materials. 
The technique according to the invention is particularly useful when 
manufacturing components to be included in aseptic or sterile systems, for 
instance packaging systems. 
BACKGROUND OF THE INVENTION 
Starting out from a known injection moulding technique, so called 
sequential injection moulding, which for instance is described in U.S. 
Pat. No. 4,448,324, according to the present invention, the actual 
technique is given a brand new utility, i.e. the possibility of providing 
high hygiene seals and manufacturing techniques for such. 
The insight that the sequential injection moulding technique allows the 
production of transition regions which are unnoticeable for the eye and 
not at least--in sterile systems --unnoticeable for bacteria and other 
micro-organisms, such unnoticeable or not existing transitions existing 
between regions of different injection mouldable materials, means the 
provision of a wide, new perspective within the technique relating to 
sealingly joining components. 
The technique suggested according to the present invention does also reduce 
the number of elements otherwise necessary for sealing purposes. 
SUMMARY OF THE INVENTION 
The present invention provides a device for forming at least a liquid tight 
joint between two elements, comprising a sealing portion arranged at 
either or both ends of the element, said portion giving said joint in an 
area intended for abutment of said elements when said elements are brought 
together in the abutment area. 
The device is characterized in that the sealing portion comprises a seal 
manufactured by sequential injection moulding technique integral with a 
region of said element at least directly adjacent to said sealing portion, 
said seal being of a material which is of a relatively softer material 
than said adjacent region. 
In one embodiment the seal continues into the said adjacent region, at 
outwardly facing free surfaces thereof, by transition surface portions 
forming continuously integral surfaces with the adjacent surface portions 
of the seal. 
In one specific embodiment the seal is arranged as a circumferencial seal 
around the edge of an opening in either element. 
The seal may be placed in a mounting flange around the opening and define 
the edge of the flange facing the inside of the opening. 
Preferably, the sealing portion or seal is formed from an injection 
mouldable material having a long term resiliency. 
In a specific embodiment the said adjacent region is injection moulded of a 
thermo-plastics material, for instance HD-polyethylene, and the sealing 
portion or seal is injection moulded of a material of the type "PERSTORP 
DRYFLEX 6". 
The invention does also provide a method for manufacturing a device for 
accomplishing of at least a liquid tight joint between two elements, 
comprising a sealing portion arranged in either or both elements, which 
sealing portion in a region intended for abutment of said elements forms 
said joint when said elements are brought together in the abutment area. 
The method is characterized in that the sealing portion or portions and 
region or regions immediately adjacent thereof are formed by sequential 
injection moulding, and that for the sealing portion there is used a 
relatively softer or more resilient material than for the area or areas 
immediately adjacent thereof. 
In one embodiment the sealing portion is injection moulded such that there 
is formed a soft transition into adjacent regions of an element, without 
the formation of any contamination collecting pockets. 
Preferably, the sealing portion is formed from a material having a long 
term resiliency. 
In one embodiment the sealing portion is formed by sequential injection 
moulding as the inner, circumferencial edge portion of a flanged opening.

DETAILED DESCRIPTION OF THE INVENTION 
The reference numerial 10 in FIG. 1 shows a flexible packaging container 
having a stud 11 attached to one side thereof, and where a joint element 
12 of the male type is arranged for being placed inside the stud for 
sealing the package. In the condition shown in FIG. 1 the package 10 is in 
the final filling stage and is maintained in filling position by means of 
a support rod 13 which grips the male element 12 internally, and by means 
of a pair of support fingers 14 gripping the female element 11 externally. 
The flanged end 16 of a filling pipe 15 is brought against the female 
element 11. There is maintained a compressing pressure between the flange 
16 and the female element 11, such that a circumferencial sealing ring 17 
provides the intended sealing function. 
In FIG. 2, in partial section, there is shown the interaction between three 
elements which in this case are necessary for the sealing procedure. The 
seal should be at least liquid tight, but in view of the fact that the 
system primarily is intended for aseptic or sterile handing, the seal 
should of course in such an application form an efficient barrier or lock 
against penetration of gas, vapour and micro-organisms. 
According to the present invention the seal in FIG. 3 is proposed, where 
the stud 11a is pressed against the flange part 16a of a filling pipe 15. 
The flange part 16a and the visible part of the filling pipe in FIG. 3 are 
manufactured from a plastics material, for instance HD-polyethylene, and 
the sequential injection moulding technique mentioned has been used such 
that a circumferencial sealing portion 17a is formed. 
In this particular embodiment said sealing portion has been injection 
moulded from a relatively softer material than the material of the part 
16a and 15. Such a material may for instance be the one sold under the 
trade name "PERSTORP DRYFLEX 6". 
The sealing portion 17a merges into the flange portion 16a, in the areas 
not visible from the outside, by a molecular bond between the molecules of 
the material of the element 17a and the material of the element 16a, 
respectively. For the rest, in the sections of the transitions facing 
outwardly, the structure has continuous and smooth surface sections, and 
there is no way of identifying, neither by the eye or at an microorganism 
level, any recesses or corresponding which might act as hearths for 
bacterial growth. 
According to the embodiment in FIG. 3, the element 11a is of a material 
which is relatively harder than the material of the sealing portion 17a 
and may for instance consist of the same plastics material as the elements 
16a, 15, i.e. HD-polyethylene. 
In FIG. 4 there is a packaging container 10' basically of the same type as 
in FIG. 1, but where the male and female parts 12' and 11' of the 
container closure include an integral seal 12'a formed by sequential 
injection moulding, i.e. the female part 11' and the circumferential 
sealing ring 17a' are formed by sequential injection moulding. A molecular 
bond is obtained between the part 11' and the ring 17a' and, additionally, 
there will be no contamination collecting pockets at the exposed border 
region, instead the molecular bond allows the formation of a perfectly 
smooth transition region at the surface facing the inside of the female 
part 11'. 
In FIG. 4 the seal 17a' cooperates with a groove 17a" in the male part 12' 
and, basically, the seal is of the radial seal type. However, the 
sequential injection moulding technique does also allow the formation of 
axial type of seals, i.e. seals of the type in FIG. 3. The type of 
material relation in FIG. 4 basically is the same as in FIG. 3. The 
softer, long term resilient material of the ring 17a' should, however, as 
the material of the ring 17a in FIG. 3, give a molecular bond, when 
injection moulded, with the material of the male part 11'. 
If necessary, the groove 17a" may also be formed by applying the sequential 
injection moulding technique. 
Within the packaging field the parts 11, 12 and 11', 12' form what is 
called a spout, i.e. a reclosable closure, especially well suited for 
bag-in-box systems. 
In one further development of the seal structure and the manufacturing 
technique thereof, the seal is injection moulded by said sequential 
injection moulding technique from a self-sterilizing termoplastics 
material. Such material compositions are known in general terms and may 
for instance include chemical systems creating ozone when exposed to 
oxidization. 
Although the invention has been exemplified in connection with a specific 
embodiment it is realised that the inventive idea is restricted merely by 
the contents of the accompanying claims.