Method for the production of a seal designed as a longitudinal seal for a linear track having a plate-shaped or bar-shaped base body that extends in a straight line or at an angle, said base body having at least one sealing lip adjoining the base body, wherein the sealing lip extends on at least one longitudinal side of the base body and is formed as a longitudinally sliding sealing lip of the longitudinal seal, wherein the seal has, at least in sections, a core made from a hard plastic, and a skin made from a comparatively weak plastic, wherein the core is substantially completely encased by the skin, wherein the base body is formed as core and skin and the base body has a main part of the core, wherein the at least one sealing lip is formed predominantly of skin, in that only one section of the core protrudes away from the base body into the connection region of the sealing lip that is otherwise formed of skin, and the core has at least one core end that passes through the skin, said core end passing through to the outside of the skin and forming an aperture, wherein the seal is produced, using sandwich technology, by injection moulding in an injection mould having a cavity that corresponds to the outer shape of the seal, wherein the injection mould has an overflow device adjoining the cavity, said overflow device being used to control the expansion of the skin component and of the core component in specific regions of the cavity, wherein the following steps take place for the production of the seal: a) skin component is injected into the cavity of the injection mould in the region of an injection site, in such a way that the skin component extends progressively within the cavity; b) core component is injected into the cavity of the injection mould containing the skin component in such a way that the core component progresses within the cavity to be at least partially encased by the skin component; c) the expansion of the skin component and of the core component in specific regions of the cavity is controlled by the overflow device by a part of the skin component and core component accommodated in the cavity overflowing out of the cavity as material overflow, and into the overflow device arranged adjoining the cavity in a region of the moulding wall. wherein the seal has, at least in sections, a core made from a hard plastic, and a skin made from a comparatively weak plastic, wherein the core is substantially completely encased by the skin, wherein the base body is formed as core and skin and the base body has a main part of the core, wherein the at least one sealing lip is formed predominantly of skin, in that only one section of the core protrudes away from the base body into the connection region of the sealing lip that is otherwise formed of skin, and the core has at least one core end that passes through the skin, said core end passing through to the outside of the skin and forming an aperture, wherein the seal is produced, using sandwich technology, by injection moulding in an injection mould having a cavity that corresponds to the outer shape of the seal, wherein the injection mould has an overflow device adjoining the cavity, said overflow device being used to control the expansion of the skin component and of the core component in specific regions of the cavity, wherein the following steps take place for the production of the seal: a) skin component is injected into the cavity of the injection mould in the region of an injection site, in such a way that the skin component extends progressively within the cavity; b) core component is injected into the cavity of the injection mould containing the skin component in such a way that the core component progresses within the cavity to be at least partially encased by the skin component; c) the expansion of the skin component and of the core component in specific regions of the cavity is controlled by the overflow device by a part of the skin component and core component accommodated in the cavity overflowing out of the cavity as material overflow, and into the overflow device arranged adjoining the cavity in a region of the moulding wall. a) skin component is injected into the cavity of the injection mould in the region of an injection site, in such a way that the skin component extends progressively within the cavity; b) core component is injected into the cavity of the injection mould containing the skin component in such a way that the core component progresses within the cavity to be at least partially encased by the skin component; c) the expansion of the skin component and of the core component in specific regions of the cavity is controlled by the overflow device by a part of the skin component and core component accommodated in the cavity overflowing out of the cavity as material overflow, and into the overflow device arranged adjoining the cavity in a region of the moulding wall.