Elastomeric films and gloves
There is disclosed a composition for producing an elastomeric film comprising: a synthetic polymer, sulphur, and a metal-oxide cross-linking agent. The concentration of the total solids in the composition is between 5-20% by weight of the composition. Also disclosed is a multiple-coating method of manufacturing an elastomeric film comprising the steps of: (i) providing a composition comprising a synthetic polymer, a cross linking agent, wherein the concentration of the total solids in the composition is between 5-20% by weight of the composition, (ii) contacting the composition with a mould to form a layer of composition on the mould, (iii) contacting the layer of composition on the mould with a further amount of the composition to form a further layer, (iv) drying the composition, and (v) curing the composition.
1. A multiple-coating method of manufacturing a layered elastomeric film comprising the steps of:
(i) dipping a mould into a coagulant containing calcium ions at a concentration of between 1% and 10% by weight, followed by
(ii) drying or partially drying the coagulant-dipped mould,
(iii) dipping the coagulant-coated mould into a composition for producing an elastomeric film having a total solids content of between 5% and 20% and a temperature of between 25° C. and 45° C. for a dwell time of between 1.0 and 10.0 seconds to produce a layer of elastomeric film composition on the mould,
(iv) drying the elastomeric film composition,
(v) dipping the mould into a composition for producing an elastomeric film having a total solids content of between 5% and 20% and a temperature of between 25° C. and 45° C. for a dwell time of between 1.0 and 10.0 seconds to produce a further layer of elastomeric film composition on the mould, directly on the preceding elastomeric film layer;
(vi) optionally repeating the drying step (iv) and the further dipping step (v), and
(vii) drying and curing the layered elastomeric film, wherein the average thickness of each layer is between 6% and 90% of the average thickness of the total layered elastomeric film, and the average thickness of the total layered elastomeric film is between about 0.01 mm and about 0.3 mm.
2. The method according to claim 1 , wherein the composition for producing an elastomeric film comprises a synthetic elastomeric polymer or copolymer.
3. The method according to claim 2 , wherein the composition for producing an elastomeric film comprises a polymer containing free ionically cross-linkable groups and covalently cross-linkable groups.
4. The method according to claim 3 , wherein the composition for producing an elastomeric film further comprises a metal oxide cross-linking agent.
5. The method according to claim 4 , wherein the composition further comprises sulphur and/or one or more accelerators.
6. The method according to claim 1 , wherein the drying step (iv) and the further dipping step (v) are repeated at least once.
7. The method according to claim 1 , wherein the film has between 2 to 15 layers.
8. The method according to claim 7 , wherein the film has between 2 to 6 layers.
9. The method according to claim 8 , wherein the film has two or three layers.
10. The method according to claim 9 , wherein the average thickness of each layer is between 30-70% of the average thickness of the total layered elastomeric film.
11. The method of claim 1 , wherein the mould is a hand-shaped mould, and the layered elastomeric film is in the shape of a glove.
12. The layered elastomeric film produced by the method of claim 1 .