| abstract |
The invention relates to water-based adhesives for industrial applications obtained by mixing water-redispersible polymer powder and water-soluble polymer powder with water, wherein the weight ratio of the water-redispersible polymer powder to the water- soluble polymer powder is from about 0.001 : 1 to 100 : 1 and the water-based adhesive has a set speed of less than 300 sec, when measured with a 36 µm thick layer at 23°C and 50% relative humidity and 385 µm thick carton boards with a weight of 275 +/- 3 g/m2 and Cobb values on one side of 43 g/min/m2 and 27 g/min/m2 on the other side, has a solids content of about 7.5 to 70 wt.-% and a Brookfield viscosity at 23°C at 20 rpm, measured according to the ASTM D1084 standard, of about 500 to 10'0OO mPas. The water-based industrial adhesive has the capability to bond a low surface tension substrate to a cellulosic substrate, in particular with a weight-ratio of water-redispersible polymer powder to water-soluble polymer powder from about 0.5 : 1 to 100 : 1 , thus can replace conventional aqueous adhesives based on synthetic polymer dispersions. The benefits of the invention are manifold such as faster set speeds and increased machine speeds, logistical advantages due to handling powders instead of liquids, leading to e.g. prolonged shelf life, no water transportation and being an environmentally friendly, low VOC containing adhesive. |