Synthetic multilayer object

Abstract

An axisymmetrical multilayer object forming a wall of thickness E, said object being composed of a first resin forming the structure of the object and representing at least 80% of the volume of the object, and of a second resin forming at least two fine functional layers, said functional layers being imprisoned separately in the first resin, the multilayer structure being characterized in that a. the functional layers are distributed in separate parts of the object b. the functional layers form bodies of revolution centered on the axis of symmetry of the object c. the two functional layers are placed partially one on top of the other in a direction perpendicular to said wall.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for realizing multilayer objects by compression molding of a multilayer dose. PRIOR ART [0002] U.S. Pat. No. 4,876,052 describes a multilayer object (FIG. 1), characterized in that a first synthetic resin 3 is fully imprisoned inside a second synthetic resin 2. This multilayer object is obtained by compression molding of a composite dose in which the first resin is totally imprisoned in the second resin. The multilayer structure described in U.S. Pat. No. 4,876,052 is particularly interesting for objects such as receptacles or lids. However, the objects obtained according to the method described in U.S. Pat. No. 4,876,052 require a large proportion of functional resin in the object, thereby engendering two major drawbacks: the first being a prohibitive cost and the second a lowered resistance to mechanical stresses. The lack of adhesion between the functional resin and the outer resin reduces the solidity of the...

AI Technical Summary

Benefits of technology

"The invention is a special object made up of two layers of resin. The first layer is made up of a resin that forms the structure of the object, while the second layer is made up of a resin that forms two thin layers. These layers are separate and are embedded within the first layer. The layers are evenly distributed throughout the object and form bodies of revolution around the object's axis of symmetry. The two layers are also partially placed on top of each other in a perpendicular direction to the wall. This design provides a unique and symmetrical appearance to the object."

Problems solved by technology

However, the objects obtained according to the method described in U.S. Pat. No. 4,876,052 require a large proportion of functional resin in the object, thereby engendering two major drawbacks: the first being a prohibitive cost and the second a lowered resistance to mechanical stresses.

The lack of adhesion between the functional resin and the outer resin reduces the solidity of the object and creates a risk of decohesion of the outer layer.

Another drawback of U.S. Pat. No. 4,876,052 lies in the fact that the respective quantity of the resins 2 and 3 is only poorly adjustable.

However, the multilayer objects realized from two resins according to patent JP 2098415 have two major drawbacks: the first being that of having the barrier resin 3 exposed on a central surface area of the object over at least 10% of the total surface area of the object, and the second being that of requiring a quantity of barrier resin 7 in the object amounting to at least 30% of the total quantity of resin.

This produces, on the one hand, objects having a prohibitive cost and, on the other hand, objects having heavily modified mechanical properties, mainly in the center of the object.

Another drawback of patent JP 2098415 lies in the fact that the respective quantity of the resins 2 and 3 is only slightly adjustable, these quantities being fixed by the geometry of the object and by the flows during the compression of the dose.

This central region of the object not covered by the barrier resin layer 3 weakens the barrier performance of the object and renders this solution less effective.

In the case of high-speed molding, it can be detrimental to use a compression device as described in patent application CH01619 / 04.

This method has the drawback of requiring a high barrier resin percentage (in the order of 20%) in order significantly to reduce the permeability of the object, since the strips do not form a continuous layer.

Another drawback of patent EP926078 lies in the fact that the position of the strips in the object cannot be controlled.

This can limit the use of the objects described in patent EP926078, for hygiene reasons, when the packaged product is in contact with the laminar multilayer object.

Another drawback of patent EP926078 is linked to the limited choice of resins, which must exhibit viscosities and melting temperatures which allow the strips to be maintained during the compression of the dose.

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