Process for the production of industrial parts of synthetic material comprising a rigid portion surmounted by a flexible portion and the industrial part produced by said process

Claim 2

Process for production of an industrial component which comprises a portion of rigid material partly surrounded by a portion of flexible material, including the steps of: making a model of said rigid portion; producing a first mould from said model; adding to the model additional material shaped and dimensioned to correspond to the shape and dimension of said flexible portion; producing a second mould from said model with said additional material thereon; placing said first mould in an injection moulding machine and injecting material to produce said rigid portion; removing said rigid portion from said first mould; inserting said rigid portion in said second mould; placing said second mould with said rigid portion inserted therein in a casting machine; and casting flexible material and uniting it to said rigid portion to produce said industrial component.

Claim 3

A process according to claim 1 wherein said rigid material is a compact polyurethane with high mechanical properties and whose density is of the order of 1 g/cm 3 .

Claim 4

A process according to claim 2 wherein said compact polyurethane is produced from straight chain polyethylene adipate with a molecular weight of from 2 to 4000, diphenyl methane isocyanate and 1, 4-butane diol.

Claim 5

A process according to claim 1 in which said flexible material is a polyurethane foam whose density is from 0.2 to 0.6 g/cm 3 and whose surface hardness is from 10 to 300 sh. A.

Claim 6

A process according to claim 1 in which said polyurethane foam comprises from 60 to 80% of open cells and from 20 to 40% of closed cells.

Claim 7

A process according to claim 1 in which the moulds are of epoxy resins.

Claim 8

A process according to claim 1 in which the moulds are of aluminum.

Claim 9

An industrial part when produced by the process according to claim 1.

Claim 10

Process for production of a sealing shutter of a heating, or air-conditioning, system which comprises a rigid portion consisting of hinges and bearing members of the shutter and a flexible portion at least partially surmounting said rigid portion, comprising the steps of: making a model of said rigid portion; producing a first mould from said model; adding to said model additional material shaped and dimensioned to correspond to the shape and dimension of said flexible portion of said shutter; producing a second mould from said model with said additional material thereon; forming within said first mould by injection moulding said rigid portion of the shutter composed of a compact poly urethane with a density of the order of 1 g/cm 3 ; removing said rigid portion from said first mould; inserting said rigid portion thus produced in said second mould and introducing into said second mould material to form therein at a temperature of about 40° C. to about 50° C. foamed polyurethane comprising about 60 to 80% of open cells and about 20 to 40% of closed cells, having a density of from about 0.2 to 0.6 g/cm 3 and a surface hardness of from about 10° to 30° sh. A and which becomes united to said rigid portion of said shutter.

Claim 11

Process for production of a sealing shutter of a heating, or air-conditioning, system which comprises a rigid portion consisting of hinges and bearing members of the shutter and a flexible portion at least partially surmounting said rigid portion, comprising the steps of: making a model of said rigid portion; producing a first mould from said model; adding to said model additional material shaped and dimensioned to correspond to the shape and dimension of said flexible portion of said shutter; producing a second mould from said model with said additional material thereon; forming within said first mould by injection moulding said rigid portion of the shutter composed of a compact poly urethane with a density of the order of 1 g/cm 3 ; removing said rigid portion from said first mould; inserting said rigid portion thus produced in said second mould and introducing into said second mould material to form therein at a temperature of about 40° C. to about 50° C. foamed polyurethane comprising about 60 to 80% of open cells and about 20 to 40% of closed cells, having a density of from about 0.2 to 0.6 g/cm 3 and a surface hardness of from about 10° to 30° sh. A and which becomes united to said rigid portion of said shutter.

Claim 12

A shutter for a central heating, or air conditioning system when produced by a method according to claim 9.