The invention relates to a method for welding two different polyolefin plastics using a primer, said primer containing at least one maleic anhydride graft polyolefin polymer. The invention also relates to correspondingly welded products.

The invention relates to a method for welding a polyolefin plastic and a plastic consisting of a polymer with at least one aromatic unit in the polymer main chain, using a primer which contains at least one polymer built from at least one monomer with at least one double bond. The invention also relates to correspondingly welded products.

The invention relates to a method for bonding two different plastics using a primer. The two plastics which are to be joined to each other have a weighted quadratic distance between the Hansen parameter (R.sub.a).sup.2 of more 22 MPa and the primer contains a polymer which has a weighted quadratic distance between the Hansen parameter (R.sub.a).sup.2 of less than 22 MPa to both of the plastics which are to be joined. The invention also relates to correspondingly bonded products.

The invention relates to a method for welding a polyamide plastic and a poly(meth)acrylateparticularly a polymethyl methacrylateplastic using a primer, said primer containing at least one copolymer synthesised from at least one styrene or styrene derivative and at least one maleic anhydride or maleic anhydride derivative. The invention also relates to correspondingly welded products.

The invention relates to a method for welding a polyolefin plastic and a plastic based on at least one polymer containing carbonyl groups, using a primer which contains, in relation to the proportion of polymer in said primer, at least 20 wt. % of a polymer that comprises maleic anhydride or maleic anhydride derivative units. The invention also relates to correspondingly welded products.

A process for producing a thermoplastic composite pipe, where the process includes: a) providing a tubular liner having a wall containing a thermoplastic polymer A in the region of the outer surface; b) providing a tape containing reinforcing fibres in a matrix containing a thermoplastic polymer B, where polymer A and polymer B are different; c) applying a film or a composite which is produced in d) and is composed of a film and a tape provided in step b) to the tubular liner, with melting of the outer surface of the liner and of the contact surface of the film either beforehand, simultaneously or thereafter, d) applying the tape provided in b) to the outer surface of the film, with melting of the outer surface of the film applied and of the contact surface of the tape either beforehand, simultaneously or thereafter,
where the surface of the film which is brought into contact with the liner contains a moulding compound containing polymer A to an extent of at least 30% by weight, and the opposite surface of the film contains a moulding compound containing polymer B to an extent of at least 30% by weight.

A process for producing a thermoplastic composite pipe is provided. The thermoplastic composite pipe thus produced contains a liner, two or more composite layers composed of tape laminas, and a single- or multilayer intermediate lamina arranged between different composite layers. Composite formation between identical polymers in the process achieves improved adhesion. The thermoplastic composite pipe is especially suitable for offshore applications in oil or gas production.

A component includes at least first and second plastics component parts which are interconnected in a connection zone. A reinforcing element includes at least one wire which bridges the connection zone. The first and second plastics component parts are welded together and/or are fused together in the connection zone. The plastics component parts may be bonded to one another.

The present invention relates to a process for the production of at least two-layer thermoplastic foam sheets via thermal welding of at least two thinner thermoplastic foam sheets. In the process of the invention, at least two heating elements are conducted on mutually offset planes between the surfaces to be welded of the thinner thermoplastic foam sheets, and the foam sheets here do not touch the heating elements. The number of layers of the thermoplastic foam sheet is per se a result of the number of thinner thermoplastic foam sheets that are thermally welded to one another. If by way of example three thinner thermoplastic foam sheets are thermally welded to one another, a three-layer thermoplastic foam sheet is per se obtained, and if there are four thinner thermoplastic foam sheets the result is accordingly per se a four-layer thermoplastic foam sheet.

A method for joining together different components or different sections of a single component, wherein at least one of the components is a thermoplastic fiber composite component, by using a threaded fastener. Heat is used for softening the thermoplastic fiber composite component to be joined together with the threaded fastener. A joined-together fiber composite component of a vehicle, aircraft or spacecraft, can be obtained by the disclosed method.