Abstract This relates to blow molded plastic containers wherein at least the body of such containers is of a laminated construction including, for example, a barrier layer which in the case of the container receiving carbonated products would be a gas barrier layer. It has been found that delamination does occur and this is now solved by selectively providing the container body with minute vent openings which do not extend entirely through the container body, but into that area where delamination occurs and there is an accumulation of a permeant, such as CO 2 . The minute vents may be formed in the exterior wall of the container either by way of piercing pins or by utilizing a laser. In the case of the piercing pins, there are incorporated in the blow mold for blow molding the container from a preform and are generally placed along the parting lines of the blow mold and also in central parts of the wall. The construction and operation of the piercing pins may be provided in several forms.
In an apparatus for forming a blow molded container having a laminated body wall including an outer layer, a gas barrier layer and at least one inner layer, and there being at least one vent opening in said container body from the exterior of said container entirely through said outer layer and said gas barrier layer, said apparatus comprising a blow mold having a cavity for blow molding said container from a preform formed with said outer layer, said gas barrier layer and said at least one inner layer, and forming means for forming said vent opening entirely through said outer layer and said gas barrier layer and terminating in said body wall.
Claim 2
Dependent Claim
113 words
In an apparatus for forming a blow molded container having a laminated body wall including an outer layer, a gas barrier layer and at least one inner layer, and there being at least one vent opening in said container body from the exterior of said container entirely through said outer layer and said gas barrier layer, said apparatus comprising a blow mold having a cavity for blow molding said container from a preform formed with said outer layer, said gas barrier layer and said at least one inner layer, and forming means for forming said vent opening entirely through said outer layer and said gas barrier layer and terminating in said body wall.
Claim 3
Dependent Claim
15 words
Apparatus according to claim 1 wherein said forming means are carried by said blow mold.
Claim 4
Dependent Claim
31 words
Apparatus according to claim 1 wherein said forming means are in the form of a piercing pin unit mounted in said blow mold for projecting a piercing pin into said cavity.
Claim 5
Dependent Claim
24 words
Apparatus according to claim 3 wherein said piercing pin unit includes a fluid motor for timed projection of said piercing pin into said cavity.
Claim 6
Dependent Claim
20 words
Apparatus according to claim 1 wherein said forming means are laser means operable separate and apart from said blow mold.