Aqueous dispersion for improving barrier properties

Fiber preparation treated with an aqueous polyolefin dispersion having a pH value from 7.5-9.4, the aqueous polyolefin dispersion containing:

• a. from 50 to 100 wt. % of an aqueous dispersion A comprising the following ingredients:
• i. from 41 to 98 wt. % of A1, A1 being a copolymer of ethylene and (meth)acrylic acid having a content of (meth)acrylic based groups of at least 14 wt. % based on the total weight of the copolymer or a mixture of different copolymers of ethylene and (meth)acrylic acid each having a content of (meth)acrylic based groups of at least 14 wt. % based on the total weight of the copolymer,
• ii. from 1 to 59 wt. % of A2, A2 being a hydrocarbon polymer containing olefinic structure units, or a mixture of hydrocarbon polymers containing other olefinic structure units, and
• iii. from 0-35 wt. % of additive different from A1 and A2,
• b. from 0 to 50 wt. % of a compound B, where compound B is a material dispersible or soluble in water and different from any of the ingredients of dispersion A
• wherein
• the wt. % of A and B is based on the solid content of the whole aqueous polyolefin dispersion,
• the wt. % of the ingredients of dispersion A is based on the solid content of dispersion A,
• the sum of the wt. % of ingredients i to iii of dispersion A is 100%.