Multi-layer wrapper construction
AssigneesCartons St-Laurent Inc., St. Laurent Paperboard Inc.
InventorSerge Koutitonsky
Life of this patent
Estimating the term…
Abstract
A multi-layer paper or paperboard construction that has good moisture vapour barrier qualities and mechanical strength and is easily repulpable. The construction permits the use of a very thin PVdC/butyl acrylate barrier layer by primer and laminant layers disposed on the inside surfaces of the paper substrates. The primer and laminant layers are a blend of a inorganic pigment dispersion and a styrene acrylate binder. The multi-layer construction has particular application as a wrapper to protect bulk rolled paper and paperboard prior to shipment from the paper mill and as a linerboard facing in corrugated boxes where liner packaging requires protection against water vapour.
Claims11
A recyclable multi-layer moisture vapour barrier construction comprising:
- (a) a first paper or paperboard substrate having an inner and outer surface;
- (b) a primer layer applied on the inner surface of said first paper or paperboard layer, said primer layer comprising an inorganic pigment and a styrene acrylate copolymer binder;
- (c) a moisture vapour barrier layer applied on the primer layer, said barrier layer comprising a copolymer of polyvinylidene chloride and butyl acrylate, the polyvinylidene chloride being present in an amount greater than that of the butyl acrylate;
- (d) a laminant layer applied on the barrier layer, said laminant layer comprising an inorganic pigment and a styrene acrylate copolymer binder;
- (e) a second paper or paperboard substrate having an inner and outer surface, said inner surface being applied on the laminant layer.
A recyclable multi-layer moisture vapour barrier wrapper construction comprising:
- (a) a first paper or paperboard substrate having inner and outer surface;
- (b) a primer layer applied on the inner surface of said first paper or paperboard layer, said primer layer comprising about 75-80 parts per 100 parts by dry weight of an inorganic pigment having at least 90% of its particle size below 2 microns and about 20-25 parts per 100 parts by dry weight of a binder of styrene acrylate copolymer having a glass transition temperature in the range of 20.degree.-25.degree. C., said primer layer being applied at a rate of about 10 to 15 gsm;
- (c) a moisture vapour barrier layer applied on the primer layer, said barrier layer comprising a copolymer of a relatively major amount of polyvinylidene chloride and a relatively minor amount of butyl acrylate and having a minimum film forming temperature in the range of 12.degree. to 18.degree. C., said barrier layer applied at a rate of about 3 to 10 gsm;
- (d) a laminant layer applied on the barrier layer, said laminant layer comprising about 75-80 parts by dry weight of an inorganic pigment having a particle size below about 15 microns and about 20-25 parts per 100 parts by dry weight of a binder of styrene acrylate copolymer having a glass transition temperature in the range of 20.degree.-25.degree. C., said laminant layer being applied at a rate of about 10 to 15 gsm;
- (e) a second paper or paperboard substrate having an inner and outer surface, said inner surface being applied on the laminant layer.
Dependencies are inferred from the claim text.