High-strength film laminates with layers of polyvinyl(n)acetal containing plasticizers and polyvinyl(iso)acetal containing plasticizers

摘要

The film laminate comprises three layers A, B and C, where each of the layers contains a plasticizer and a polyvinyl acetal. One of the layers A, B or C contains polyvinyl(iso)acetal as polyvinyl acetal having an average degree of polymerization of less than 3000, a proportion of polyvinyl alcohol groups of 10-25 wt.% and an amount of polyvinyl(iso)acetal group of 50-80 wt.%, where a layer B is arranged between the layers A and C. A content of the plasticizer is less than 32 wt.%. The layer B comprises a polyvinylacetal having a proportion of polyvinyl alcohol groups. The film laminate comprises three layers A, B and C, where each of the layers contains a plasticizer and a polyvinyl acetal. One of the layers A, B or C contains polyvinyl(iso)acetal as polyvinyl acetal having an average degree of polymerization of less than 3000, a proportion of polyvinyl alcohol groups of 10-25 wt.% and a proportion of polyvinyl(iso)acetal group of 50-80 wt.%, where a layer B is arranged between the layers A and C. A proportion of the plasticizer is less than 32 wt.%. The layer B comprises a polyvinylacetal having a proportion of polyvinyl alcohol groups, which are equal to or greater than the proportion of polyvinyl alcohol groups of the polyvinyl acetal in the layers A and C. The layers are made of a composition comprising: a first plasticizer and a first polyvinyl(iso)acetal with a proportion amount of polyvinyl(iso)acetal group of 50-80% wt.% and the proportion of polyvinyl alcohol groups of 10-25 wt.%; a second plasticizer and a polyvinyl(n)acetal with the proportion of polyvinyl alcohol groups of 10-25 wt.%; a third plasticizer and a second polyvinyl(iso)acetal with the proportion of polyvinyl(iso)acetal of 50-80 wt.% and the proportion of the polyvinyl alcohol groups of 10-25 wt.%; a first plasticizer and a first polyvinyl(n)acetal with a proportion amount of polyvinyl(iso)acetal group of 10-25 wt.%; a second plasticizer and polyvinyl(iso)acetal with the proportion of polyvinyl(iso)acetal groups of 50-80 wt.% and the proportion of polyvinyl alcohol groups of 10-25 wt.%; a third plasticizer and a second polyvinyl(n)acetal with the proportion of polyvinyl alcohol groups of 10-25 wt.%; a second polyvinyl(iso)acetal with the proportion of polyvinyl(iso)acetal of 50-80 wt.% and the proportion of polyvinyl alcohol groups of 10-25 wt.%; and a third plasticizer and a third polyvinyl(iso)acetal with the proportion of polyvinyl(iso)acetal group of 50-80 wt.% and the proportion of polyvinyl alcohol groups 10-25 wt.%. The layers have a plasticizer content, which differs by less than 10 phr. The film laminate is produced by coextrusion and merging of the layers. The polyvinyl(iso)acetal results from a reaction of polyvinyl alcohol with aliphatic keto compounds having 4-10C with a branch at alpha -position or beta -position to a keto group and with aliphatic, unbranched keto compound having 2-10C.