Abstract: The invention relates to a light-transmitting gasket intended to be positioned on the base of a stopper or cap, in the form of a support having a light-transmitting coating applied to at least one of the surfaces thereof. The gasket is characterised in that the coating contains a watermark, i.e. an image visible in transmitted light, but not visible in reflected light.

Abstract: Sealing disc (1) for closing a container having a plug or cap closure, comprising a support (2) to be positioned at the bottom of the plug or of the cap, joined by means of a temporary adhesive (7) to a membrane seal (3) to be sealed on the mouth of the container, the membrane seal (3) being provided on all or part of its thickness with a prolongation constituting a pull tab (4), characterized in that the whole surface of the tab is folded back on the face of the membrane seal (3) in contact with the corresponding face of the support (2).

Abstract: Heat-sealable seal including a support bonded to an inner seal by a temporary adhesive is provided. The inner seal has a pull-tab which is folded back once on the surface of the inner seal in contact with the corresponding surface of the support. The inner seal includes a laminate having a reinforcing layer and a sheet of a conducting material, to the lower surface of which is applied a heat-sealing film. The temporary adhesive is applied to the whole surface of the inner seal once the pull-tab is folded back. The seal is characterized in that the laminate has over its entire thickness a notch from which the pull-tab emerges, and a fold line formed by the pull-tab once the pull-tab is folded back, the fold line having a shorter length than the length of the notch. Methods of producing the seal are also disclosed.

Abstract: Heat-sealable seal including a support bonded to an inner seal by a temporary adhesive is provided. The inner seal has a pull-tab which is folded back once on the surface of the inner seal in contact with the corresponding surface of the support. The inner seal includes a laminate having a reinforcing layer and a sheet of a conducting material, to the lower surface of which is applied a heat-sealing film. The temporary adhesive is applied to the whole surface of the inner seal once the pull-tab is folded back. The seal is characterized in that the laminate has over its entire thickness a notch from which the pull-tab emerges, and a fold line formed by the pull-tab once the pull-tab is folded back, the fold line having a shorter length than the length of the notch. Methods of producing the seal are also disclosed.

Abstract: Heat-sealable seal including a support bonded to an inner seal by a temporary adhesive is provided. The inner seal has a pull-tab which is folded back once on the surface of the inner seal in contact with the corresponding surface of the support. The inner seal includes a laminate having a reinforcing layer and a sheet of a conducting material, to the lower surface of which is applied a heat-sealing film. The temporary adhesive is applied to the whole surface of the inner seal once the pull-tab is folded back. The seal is characterized in that the laminate has over its entire thickness a notch from which the pull-tab emerges, and a fold line formed by the pull-tab once the pull-tab is folded back, the fold line having a shorter length than the length of the notch. Methods of producing the seal are also disclosed.

Abstract: Sealing disc (1) for closing a container having a plug or cap closure, comprising a support (2) to be positioned at the bottom of the plug or of the cap, joined by means of a temporary adhesive (7) to a membrane seal (3) to be sealed on the mouth of the container, the membrane seal (3) being provided on all or part of its thickness with a prolongation constituting a pull tab (4), characterized in that the whole surface of the tab is folded back on the face of the membrane seal (3) in contact with the corresponding face of the support (2).

Abstract: A process for making a dispersion of a high viscosity siloxane in a volatile cyclosiloxane comprises the step of effecting ring-opening polymerisation of a volatile cyclosiloxane under catalysis by a phosphazene base, and the step of stopping the polymerisation reaction before completion of the ring-opening polymerisation of the cyclosiloxane has occurred. Preferably the polymerisation reaction is stopped by adding carbon dioxide or an acid.

Abstract: A process for the ring-opening polymerisation of cyclosiloxanes, which comprises contacting a cyclosiloxane with 1-500 ppm by weight of a phosphazene base, based on the weight of cyclosiloxane, in the presence of water, preferably 0.5-10 mols per mol of phospazene base. Also claimed is a process in which the cyclosiloxane is present together with an agent which inhibits catalyst activity of the phosphazene base, e.g. carbon dioxide or water, in which the polymerisation is initiated by reducing the effect of the inhibiting agent e.g. by heating.