Method of moulding containers from at least two different plastic materials, machine for carrying out this method and containers obtained thereby

Claim 1

A method of moulding hollow objects such as containers from plastic material consisting of at least two compatible plastic materials which are sealable to each other and which differ in either of their nature and their colour, said method including the steps of providing a mould and a counter-mould, as well as arranging them so as to leave an injection space between the wall of said mould and the wall of said counter-mould and injecting said component material of said article of manufacture into said injection space, wherein the improvement comprises the following operating steps: a--defining within said space through separating means at least one first sub-space and one second sub-space which are contiguous to each other at a junction zone in the region of said separating means; b--injecting into said first sub-space a first one of said two materials in a predetermined volume computed to be just that required to fill said first sub-space substantially; c--injecting into said second sub-space a second one of said two materials; d--removing said separating means while said first material is still fluid in said junction zone; and e--continuing injection of said second material under a predetermined pressure such that the total volume of said second material injected is larger than that of said second sub-space so as to achieve a local interpenetration of said second material into said first material within said junction zone between said spaces.

Claim 2

A method of moulding hollow objects such as containers from plastic material consisting of at least two compatible plastic materials which are sealable to each other and which differ in either of their nature and their colour, said method including the steps of providing a mould and a counter-mould, as well as arranging them so as to leave an injection space between the wall of said mould and the wall of said counter-mould and injecting said component material of said article of manufacture into said injection space, wherein the improvement comprises the following operating steps: a--defining within said space through separating means at least one first sub-space and one second sub-space which are contiguous to each other at a junction zone in the region of said separating means; b--injecting into said first sub-space a first one of said two materials in a predetermined volume computed to be just that required to fill said first sub-space substantially; c--injecting into said second sub-space a second one of said two materials; d--removing said separating means while said first material is still fluid in said junction zone; and e--continuing injection of said second material under a predetermined pressure such that the total volume of said second material injected is larger than that of said second sub-space so as to achieve a local interpenetration of said second material into said first material within said junction zone between said spaces.