Patent GB-451592-A (GB)
Title: Hand-rails and the like for public conveyances
IPC: B60N3/02
Filed: 1935-02-05
Abstract: Elastic phenol formaldehyde resins for casting on to hand rails &c. for public conveyances are made, according to one example by condensing phenol or cresol under reflux with formaldehyde and lactic acid, dimethylamine or sodium bicarbonate.  After the resin has separated out, it is removed from the supernatant solution, and, after addition of glycerol is evaporated in vacuo until a product which is thickly liquid at room temperature is formed.  In a further example, phenol or cresol are preliminarily condensed under reflux with formaldehyde and a sodium hydroxide solution. After preliminary condensation, which may continue until the artificial resin separates out, the sodium hydroxide is neutralized with acid e.g. hydrochloric, phosphoric acetic or lactic acid and the resin thereupon evaporated in vacuo.  Before this evaporation, glycerol may be added.  The glycerol may be replaced by glycol or triacetin and the sodium hydroxide by sodium bicarbonate, potassium hydroxide, &c.ALSO:Hand-rails and like supports for public conveyances comprise a tubular or solid metal core provided with a cast-on sheathing of hardened phenol-formaldehyde resin.  The sheathing may range from 1 mm. to about 10 mm. in thickness.  The resin is cast on to the core in a mould and then hardened.  Elastic phenol-formaldehyde resins are used and are hardened at about 60 to 80 DEG  C., if necessary under pressure.  In one example, 10 kgms. of phenol or cresol are condensed under reflux with 10-15 kgm. of formaldehyde and 1 kgm. of dimethylamine or 50-100 gm. of sodium bicarbonate. After the resin has separated out, it is removed from the supernatant solution and, after addition of 2 kgm. of glycerol is evaporated in vacuo at temperatures not greater than 100 DEG  C. until a product which is thickly liquid at room temperature is formed. The resin is poured into the mould containing the metal core and the mould and cast resin are heated to harden the resin.  In a second example 10 kgm. of phenol or cresol are condensed under reflux with 15-20 kgm. of formaldehyde and 1 kgm. of lactic acid. The separated condensation product, after the addition of 2 kgm. of glycerol is evaporated in vacuo and cast and hardened as in the first example.  In a third example, 10 kgm. of phenol or cresol are preliminarily condensed under reflux with 15-50 kgm. of formaldehyde and 100-2000 gm. of a 25 per cent sodium hydroxide solution.  After preliminary condensation, which may continue until the artificial resin separates out, the sodium hydroxide is neutralized with acid, e.g. hydrochloric, phosphoric, acetic or lactic acid and the resin thereupon evaporated in vacuo as in the first example.  Before this evaporation, 1-2 kgm. of glycerol may be added to impart elasticity.  The casting and hardening proceed as in the first example.  The glycerol may be replaced by glycol or triacetin and the sodium hydroxide by sodium bicarbonate, potassium hydroxide, &c.ALSO:Hand-rails and like supports for public conveyances comprise a tubular or solid metal core provided with a cast-on sheathing of hardened phenol-formaldehyde resin.  The sheathing may range from 1 mm. to about 10 mm. in thickness.  The resin is cast on to the core in a mould and then hardened.  Elastic phenol-formaldehyde resins are used and are hardened at about 60 to 80 DEG  C., if necessary under pressure.  Examples of methods of preparing and hardening the resin are given in the Specification.