GB863872A - Improvements in or relating to calenders and rolls therefor - Google Patents

Abstract

863,872. Embossing surfaces. DORNBUSCH, P., [trading as DORNBUSCH & CO.]. March 28, 1958 [April 26, 1957; Dec. 5, 1957; Dec. 7, 1957], No. 9948/58. Class 100(2) An embossing calender has an embossing roll and a counter roll, each roll comprising a core covered by a jacket of elastically yieldable material, the jacket of the embossing roll comprising a seamless band which carries the embossing pattern and is formed of a settable synthetic material, e.g. a polymer of vinyl chloride or silicone rubber, which is readily deformable before setting and which after setting is elastically yieldable. The formation of the pattern on the embossing roll jacket may be effected by any known method or with the aid of the apparatus shown in the drawing wherein an outer cylindrical member 1 has end flanges 2, 3 to which are detachably secured covers 5, 4 respectively by wing nuts 6. The flange 2 and cover 4 each have an annular collar 7 and a perforated cylinder 8 is clamped between the two collars 7. The covers 4, 5 have connection pipes 12, 14 which communicate with the space 13 within the cylinder 8, and central bores through which a core 15 can be inserted. A flexible tubular pattern mould 11 is formed by coating a cylindrical roller pattern of the same size and bearing the same positive design as the desired embossing roller with a paste-like synthetic material which when set has an elastic property and is pulled off the pattern roller to form a seamless tube bearing the negative design on its inner surface. The pattern mould 11 is fitted inside the perforated cylinder 8 and suction is applied to the annular space 9 between the members 1 and 8 through a connection 10 whereby the pattern mould is held closely against the inner wall of the cylinder 8. Alternatively this may be effected by introducing hydraulic fluid through the connections 12, 14. A mass of paste-like synthetic material is introduced through the pipe 14 into the space 13 surrounding the core 15, air in the space (or the hydraulic fluid if this has been used) escaping through the pipe 12. When the space 13 is filled the connection 14 is closed and a heating or cooling medium is introduced through the connection 10 to set the synthetic material. Once the material is set the cover 4 is removed and the core 15 surrounded by a jacket of the material is withdrawn from the cylinder 8: the mould 11 I is stripped off the outside of the jacket leaving the completed roller bearing the positive design on the outside of the jacket. A jacket for the counter roll bearing the negative of the pattern carried by the embossing roll may be formed by replacing the core 15 with a drum whose diameter is such that a narrow annular space is left between it and the pattern mould 11. The annular space is filled with paste-like synthetic material which is allowed to set and form a second tubular pattern mould. This second mould is removed from the drum and turned inside out; it is then used to produce the counter roll in the same way as the first pattern mould was used to make the embossing roll.