From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Technical document detailing the properties and applications of cellular rubber, including insulation and bonding to metal.
| Identifier | ExFiles\Box 178\2\ img060 | |
| Date | 25th March 1940 guessed | |
| -5- It is very effective in both cases. Here are 2 boxes of equal size and thickness. One is made of pinewood, the other of cellular rubber. In each there is an electric horn which I can turn on from these switches. As a heat insulator rubber offers several advantages. It is waterproof and does not absorb water. This is a point of more importance than might be expected because heat insulation is frequently required under conditions where condensation and absorption of water are sufficient to reduce materially the efficiency of a number of standard types of insulating material. (Passenger Aircraft. Refrigerator cars.) Cellular rubber being of course flexible and stretchable can be made to conform to any shape or can be molded to any desired special shape. As a further illustration of the versatility of rubber, the cellular structure can be made in either hard or soft rubber. Here is an example of a hard rubber cellular board weighing only 5 1/2 pounds per cubic foot. It has all the needed stiffness and permanence required for board types of insulation. It has already been thoroughly tested and its applications are rapidly increasing. One objection which had to be overcome was that of inflammability. Because of the large surface area which accompanies low density, cellular rubber would burn readily if the rubber were an ordinary hard rubber compound. It was therefore necessary to develop special compounds which have reduced the flammability to very satisfactory levels. This hard cellular rubber with noncommunicating pores is now being produced in considerable volume and because of its permanent insulating qualities and lack of water absorption it should find a growing market. Bonding: Progress is continuing in improving the adhesion of rubber to metal. It is now possible to adhere rubber to almost any metal with bond strengths definitely higher than they were a few years ago. This has had an interesting effect on design because with weaker bonds it was necessary to resort to numerous complications in design or to add compressive forces to supplement the bond between the metal and rubber. Today bond strengths have improved to the point where we can simplify some of the designs depending only on the rubber to metal adhesion to hold the pieces together. The best bonds are still obtained on brass plate surfaces but cements have been improved to the point where very satisfactory results can be obtained in numerous applications without the brass plating. Rubber tank linings are an example of such an application in which the benefits of the chemical resistance of rubber can be conferred on steel tanks, by lining them with rubber of suitable composition. In these cases simple adhesion is obtainable with the cements which are now available, and linings can be applied either at the rubber manufacturer's plant or in the customer's factory. | ||