IE43554B1 - Synthetic resin containers - Google Patents

Abstract

1517100 Plastics bottles LONZA Ltd 3 Dec 1976 [9 Jan 1976] 39726/76 Heading B8D [Also in Division B5] A plastics vessel, e.g. a bottle, comprises an inner layer 2 made of a "fresh" synthetic resin material and an outer thicker layer 3 made from waste synthetic resin material derived from used plastics vessels. The inner and outer layers may be shaped together, e.g. by co-extrusion, deep-drawing, co-extrusion blowing, co-injection moulding processes and combinations thereof, or the inner layer applied subsequently. In one example used containers, which have been formed in an injection-blow mould from an externally injection-coated deep drawn preform, are ground up and the resultant granulate utilized to form the external coating on another deep-drawn preform to form a container according to the invention. In another example, used vessels initially deep-drawn from a twolayer laminate are ground up, and the granulate utilized to form the outer layer of a two-layer laminate from which vessels are deep-drawn. Polyvinyl chloride, polypropylene, polyesters, ABS, and other acrylonitrile copolymers may be used for the "fresh" and "waste" layers, specific examples and combinations being given.

Description

The present invention is concerned with a vessel made of synthetic resin «hich comprises an external mantle layer and an internal layer, said inner layer being thinner than said outer layer, and is also con5 cemed with a process for producing such a vessel.

The importance of synthetic resins in the packaging industry is of ever increasing importance but, coupled with it, is also the problem of disposing of waste synthetic resins.

The idea of further utilising synthetic resin waste is not new. Thus, empty waste vessels are collected, washed and ground and from the synthetic resin granulates thus obtained, possibly with the addition of fresh material, new synthetic resin vessels Ij are produced. The vessels thus obtained from waste synthetic resin do not, however, satisfy the hygienic standards which are demanded in the foodstuff industry.

It is an object of the present invention to provide hygienically satisfactory vessels made from synthetic resin.

According to the present invention, there is provided a vessel made from synthetic resin, comprising an outer mantle layer and an inner layer, said inner layer being thinner than said outer layer, the outer : 25 mantle layer being made of synthetic resin from recycled vessels and the inner layer being made of fresh synthetic resin which is compatible with the synthetic resin of the mantle layer.

The present invention also provides a process 30 for the production of such a vessel, wherein a vessel -24 3 S a 4 is first produced from fresh synthetic resin and an outer layer, which is compatible with the fresh synthetic resin, is applied thereto, said outer layer being produced from a granulate obtained by grinding recycled vessels.

The inner coating can be carried out simultaneously with the production of the whole vessel or it can be carried out subsequently. However, coating is preferably carried out simultaneously during the production of the whole vessel. Numerous processes are available for this purpose, for example, co-extrusion (coating, laminating), deep drawing, co-extrusion blowing, co-injection moulding, co-injection mouldingblowing and combinations thereof. According to these processes, both materials, i.e. the regenerate and the fresh synthetic resin material, are simultaneously introduced into a mould and bonded.

The two materials, i.e. the recycled synthetic resin and the fresh synthetic resin, must be compatible with one another. By compatible in the meaning of the present invention, it is to be understood that the recycled synthetic resin, with regard to its properties, is not so influenced by the fresh synthetic resin up to a mixing ratio of 50:50 by weight that a substantial impairment of the properties occurs.

The thickness of the mantle and inner layers can be varied very considerably but a thickness ratio of mantle layer to inner layer of 10:5 to 10:0.01 is preferred.

Any thermoplastic material can be used for the outer layer, provided that the material of the inner -3layer is compatible therewith. Furthermore, the same material can also be used for both layers.

According to the present invention, it is possible to produce vessels, the inner layer of Which consists of a material which has liquid and/or gas barrier properties. Such materials include, for example, polypropylene, which serves as a barrier for water vapour, and acrylonitrile-containing synthetic resins, such as a graft polymer of acrylonitrile and methyl acrylate on an acrylonitrile-butadiene co-polymer, which has a barrier action to carbon dioxide and oxygen.

Typical material combinations of recycled synthetic resin/fresb synthetic resin layer include the following: polyvinyl chloride/polyvinyl chloride polyolefin/polypropylene polyester/polyester acrylonitrile-styrene co-polymer/acrylonitrile-styrene graft ter-polymer on a butadiene-acrylonitrile copolymer acrylonitrile-methyl acrylate co-polymer/graft polymer of acrylonitrile-methyl acrylate on an acrylonitrileerne thyl acrylate co-polymer acrylonitrile-styrene co-polymer/graft polymer of acrylonitrile-methyl acrylate on an acrylonitrilebutadiene or acrylonitrile-isoprene co-polymer acrylonitrile-methyl acrylate co-polymer/graft polymer of acrylonitrile-methyl acrylate on an acrylonitrilebutadiene co-polymer.

The recycled synthetic resin can be produced by grinding recycled vessels, grinding under water being preferred. The number of recyclings is not critical _4_ so long as the requirements for the packaging are fulfilled.

The vessels according to the present invention, for example bottles, containers, kettles and the like, always have a physiologically satisfactory inner layer due to their special construction and can be used for all packaging purposes.

The following Examples are given for the purpose of illustrating the present inventions io Example 1.

A deep-drawn preform made from an acrylonitrile graft polymer of the kind known under the Trade Mark Barex 210 was applied to the core of an injection blowing machine.

A co-polymer comprising about 75% by weight acrylonitrile and about 25% by weight methyl acrylate was injected thereon at a temperature of from 140 to 170°C. to give a container, biaxial orientation thereby resulting. The weight ratio of the inner “Barex layer 20 to the outer acrylonitrile-methyl acrylate co-polymer layer was 1:20. The container was transparent, hard and resistant to impact.

After use, the container was recycled and ground to a coarse granulate. The regenerate thus obtained was further used as injection mould material for producing an outer mantle in the above-described manner. The deepdrawn preform was made of fresh Barex 210.

After 10 recyclings, the outer layer material consisted of about 64.5% by weight acrylonitrile-methyl acrylate co-polymer and about 35.5% by weight Barex 210. In comparison with the original acrylonitrile-5methyl acrylate co-polymer, this mixture showed an increase of the impact tensile strength of about 90% with approximately the same elasticity modulus.

Example 2.

In the manner described in Example 1, a preform of a graft polymer of acrylonitrile-styrene on a butadiene-acrylonitrile co-polymer was used and the outer layer vras formed from an acrylonitrile-styrene co-polymer. Here again, after use and recycling, the container was ground and used again for the outer mantle. The inner layer was formed from fresh graft polymer of acrylonitrile-styrene-butadiene.

Example 3. ............. ' 1 Containers were formed in the manner described in Example 1 in which not only the inner layer but also the outer layer consisted of polyethylene terephthalate.

Example 4.

A bonded foil, which had been produced by coextrusion, laminating or coating, consisting of two layers of a graft polymer of acrylonitrile-methyl acrylate on an acrylonitrile-butadiene co-polymer of the type known under the trade name of Barex 210, was deep drawn to form a container.

The regenerate, obtained by grinding the used and recycled container, was used for the production of the outer layer of a new container. The inner layer was made from fresh Barex 210. After about 10 such recyclings, the properties of the outer layer of the container were just about the same as the original outer 3θ layer.

In the Figure of the accompanying drawing, there -6ie illustrated, by way of example, a vessel according to the present invention in the form of a synthetic resin bottle (1), consisting of an outer thick-walled mantle layer (3) made from a regenerate obtained by recycling and an inner thin-walled layer (2) made from fresh material.

Claims (11)

1. A vessel made from synthetic resin, comprising an outer mantle layer cod an inner layer, said inner layer being thinner than said outer layer, the outer mantle 5 layer being made of synthetic resin from recycled vessels and the inner layer being made of fresh synthetic resin which is compatible v/ith the synthetic resin of the mantle layer.

2. A vessel according fo claim 1, wherein the inner 10 layer is made Of a synthetic resin with barrier properties

3. A vessel according to claim 1 or 2, wherein the inner layer is made of polypropylene.

4. A vessel according to claim 1 or 2, wherein the inner layer is made of a synthetic resin material with 15 a high content of acrylonitrile.

5. A vessel according to claim 4, wherein the inner layer is made of a graft polymer of acrylonitrile-acrylic acid ester grafted on to an acrylonitrile-butadiene and/or acrylonitrile-isoprene co-polymer. 20

6. A vessel according to any of the preceding claims, wherein the thickness ratio of the mantle layer to the inner layer is 10:5 to 10:0.01.

7. A vessel according to any of the preceding claims, wherein the mantle layer and the inner layer are made of 25 the same material.

8. A vessel according to claim 1, substantially as hereinbefore described and exemplified.

9. A process for the production of a vessel according to claim 1, wherein a vessel is first produced from fresh 30 synthetic resin and an outer layer, which is compatible v/ith the fresh synthetic resin, is applied thereto, said -8•·ΐ H ΰ α 4 outer layer being produced from a granulate obtained by grinding recycled vessels.

10. A process for the production of vessels according to claim 1, substantially as hereinbefore described and 5 exemplified.

11. Vessels according to claim 1, whenever produced by the process according to claim 9 or 10.