An aqueous adhesive composition containing a graft copolymerized product of low amylose starch and acrylamide with rheological and remoistening adhesive properties suitable for coating low basis weight kraft paper on transfer roll coating equipment to make remoistenable sealing tapes. The desired properties of the adhesive composition are obtained by a controlled graft copolymerization together with a simultaneous gelatinization of the starch at temperatures below 210.degree. F. and with the essential addition of cupric or ferric ions before initiating the reaction. The resulting coatable adhesive has a comparatively low viscosity as required for transfer roll coating while retaining the improved adhesion properties of the acrylamide.
RELATED APPLICATIONS
This application is a continuation-in-part of our prior pending application, Ser. No. 103,596, filed Dec. 14, 1979, now abandoned.
A particulate substantially homogeneous polymeric product is made by dispersing ungelatinised polysaccharide in aqueous monomer containing polymerization initiator, initiating polymerization and thereby inducing exothermic polymerization, utilizing the exotherm to provide part at least of the heat necessary to gelatinise the polysaccharide and thereby producing a comminutable gel comprising polymerized monomer and gelatinised polysaccharide, comminuting the gel and drying the comminuted gel. The product generally comprises a blend of water soluble synthetic polymer, gelatinised polysaccharide having a low degree of graft polymerization and optionally gelatinised polysaccharide. Products comprising these components are particularly suitable for use as wallpaper adhesives.
A transfer roll coating color is described comprising a pigment and an adhesive as main components, wherein the average aspect ratio of the pigment is 10 or less, the adhesive is a low viscosity starch adhesive, the solids content of the color is about 58 weight % or higher, and the viscosity of the color determined at 60 rpm by using a No. 4 rotor of a Brookfield.TM. viscometer is 1,500 cps or less. Coated papers obtained by transfer roll coating using the colors at an amount of 5 g/m2 or higher per side also are disclosed.
Novel adhesive products are prepared by coating a novel adhesive formulation onto appropriate substrates. The adhesive formulation is capable of maintaining coatable viscosity at solids levels in excess of 58% and may comprise an interpolymer prepared in the presence of a high concentration of chain transfer agents, and may also comprise external and/or internal crosslinking agents. The Williams Plasticity Number of solids from the formulation may be less than 1.8 (determined in the absence of external crosslinking agents). Alkyl acrylamidoglycolate alkyl ether monomer copolymerized with a more reactive monomer provides an interpolymer having reduced need for strong acid catalysis.
Novel adhesive products are prepared by coating a novel adhesive formulation onto appropriate substrates. The adhesive formulation is capable of maintaining coatable viscosity at solids levels in excess of 58% and may comprise an interpolymer prepared in the presence of a high concentration of chain transfer agents, and may also comprise external and/or internal crosslinking agents The Williams Plasticity Number of solids from the formulation may be less than 1.8 (determined in the absence of external crosslinking agents). Alkyl acrylamidoglycolate alkyl ether monomer copolymerized with a more reactive monomer provides an interpolymer having reduced need for strong acid catalysis.
Alkenyl succinic anhydride (ASA) size emulsions are prepared using a grafted cationic acrylamide starch co-polymer as an emulsification agent. The ASA size emulsions of the present invention exhibit significantly greater stability compared to presently available ASA size emulsions. The grafted starch co-polymer also is a more efficient emulsification agent for ASA size, permitting the use of less emulsification agent, thereby saving cost.
