Patent GB-957933-A (GB)
Title: Method of manufacturing improved corrugated paperboard
Inventor: KRESSE HERMAN JOSEPH
IPC: D21H17/34
Filed: 1962-10-01
Abstract: A wax-copolymer blend comprises about 40%-75% by weight of the wax-paraffin wax and microcrystalline wax are mentioned, with the remainder comprising the copolymer.  Suitable copolymers are ethylene-vinyl acetate copolymer -with about 60-80% (preferably about 72%) by weight of ethylene-, ethylene ethyl acrylate copolymer-with about 65-85% by weight of ethylene-, or mixtures of these copolymers. The blend may be prepared by heating about half the wax to about 250-300 DEG F. in a high shear mixer, adding the copolymer to form a concentrate in which there are no discrete particles of the copolymer, and finally adding the rest of the wax. If the copolymer used has marginal heat sealing properties an additive-for example polyethylene or various rubbers of which examples are given-may be added.  Wax additives-for example an antioxidant-may also be used.ALSO:A wax-copolymer blend comprises about 40-75% by weight of the wax-paraffin wax and microcrystalline was are mentioned-with the remainder comprising the copolymer. Suitable copolymers are ethylene-vinyl acetate copolymer-with about 60-80% (preferably about 72%) by weight of ethylene-, ethylene ethyl acrylate copolymer-with about 65-85% by weight of ethylene-or mixtures of these copolymers. The blend may be prepared by heating about half the wax to about 250-300 DEG  F. in a high shear mixer, adding the copolymer to form a concentrate in which there are no discrete particles of the copolymer, and finally adding the rest of the wax.  If the copolymer used has marginal heat-sealing properties an additive-for example polyethylene or various rubbers of which examples are given, may be added. Wax additives-for example an antioxidant-may also be used.ALSO:A corrugated paper-board comprises at least one corrugated layer coated with a wax-copolymer blend, and at least one monoplanar liner bonded to the corrugated layer through the blend. The blend is applied to both sides of the paper layer by not roll "kiss" coating, gravure coating or curtain coating.  The layer is then passed through corrugating rollers at about 100-110 DEG F, and the liner, heated sufficiently to effect a proper seal, is brought into contact with the corrugated layer.  A second liner, if desired, is bonded in like manner to the other side of the corrugated layer while a double-walled corrugated board may be formed (Fig. 3 not shown). Penetration of the blend into the paper may be increased by heating the paper in an oven or by first applying wax to the paper followed by a thin coating of the blend.  The blend or just the wax itself may be applied to one or both sides of the liner(s).  A suitable blend comprises about 40%-75% by weight of the wax-preferably paraffin wax or perhaps microcrystalline wax-and the remainder comprising the copolymer. Suitable copolymers are ethylene-vinyl acetate copolymers-with about 60-80% by weight ethylene-, ethylene ethyl acrylate copolymer-with about 65-85% by weight ethylene-, and mixtures of these copolymers.  If the copolymer used has marginal heat sealing properties an additive may be included - for example polyethylene or a rubber (examples given) - while a wax additive, - for example an antioxidant may also be included.