Multilayer film comprising layer of plasticized polyvinyl acetal with reduced flowability

Patent metadata

Field	Value
Publication number	US-10603882-B2
Application number	US-201716091724-A
Country	US
Kind code	B2
Filing date	Apr 5, 2017
Priority date	Apr 8, 2016
Publication date	Mar 31, 2020
Grant date	Mar 31, 2020

Abstract

A multilayer laminating film contains at least one first and one second layer of plasticized polyvinyl acetal, wherein the first layer comprises a first plasticizer and a first polyvinyl acetal with a degree of acetalization of 75.1-84.0 mol % and a molar ratio of continuous sequences of vinyl alcohol groups with 5 members with a stereochemical sequence of rrrr of more than 0.23 based on the total amount of continuous syndiotactic sequences of vinyl alcohol groups with 3 members in the polyvinyl acetal, and the second layer comprises a second plasticizer and a second polyvinyl acetal with a degree of acetalization of 60-84 mol %.

First claim

The invention claimed is:

1. A multilayer film comprising at least one first and one second layer of plasticized polyvinyl acetal, wherein the first layer comprises a first plasticizer and a first polyvinyl acetal with a degree of acetalization of 75.1-84.0 mol % and a molar ratio of continuous sequences of vinyl alcohol groups with 5 members with a stereochemical sequence of rrrr of more than 0.23 based on the total amount of continuous syndiotactic sequences of vinyl alcohol groups with 3 members in the polyvinyl acetal and the second layer comprises a second plasticizer and a second polyvinyl acetal with a degree of acetalization of 60-84 mol %.

2. The multilayer film of claim 1 , comprising at least one first layer and at least two second layers, wherein a first layer is embedded between two second layers.

3. The multilayer film of claim 1 , comprising at least two first layers and at least one second layer, wherein a second layer is embedded between two first layers.

4. The multilayer film of claim 1 , wherein the first polyvinyl acetal has a molar ratio of continuous syndiotactic sequences of vinyl alcohol groups with 3 members of at least 0.13 based on the total amount of vinyl alcohol groups in the first polyvinyl acetal.

5. The multilayer film of claim 1 , wherein the first polyvinyl acetal has a solution viscosity in a 5% by weight solution in ethanol of more than 80 mPas.

6. The multilayer film of claim 1 , wherein the first and/or second polyvinyl acetal has/have a residual acetate content of 0.1 to 8 mol %.

7. The multilayer film of claim 1 , wherein the first polyvinyl acetal has a polymerisation degree of less than 2500.

8. The multilayer film of claim 1 , wherein the total plasticizer content of the combined layers is from 10 to 42% by weight based on the total weight of the multilayer film.

9. The multilayer film of claim 1 , wherein one first layer of polyvinyl acetal comprises 10-60% plasticizer by weight and 90-40 wt. % of the first polyvinyl acetal.

10. The multilayer film of claim 1 , wherein one second layer of polyvinyl acetal comprises 10-40% plasticizer by weight and 90-60 wt. % of the second polyvinyl acetal.

11. The multilayer film of claim 1 , wherein the film exhibits a surface structure created by melt fracture or by embossing having a surface roughness Rz between 10 and 100 μm.

12. The multilayer film of claim 1 , wherein a mixture of the first plasticizer and the first polyvinyl acetal has a melt flow rate at 100° C. (MFR 100) of less than 220 mg/10 min.

13. The multilayer film of claim of claim 1 , which has a wedged-shaped profile.

Assignees

• Kuraray Europe Gmbh

Inventors

• Steuer Martin
• Wenzlik Daniel
• Kusudo Takeshi
• Lellig Philipp
• Keller Uwe

Classifications

• B32B2405/00

  Adhesive articles, e.g. adhesive tapes · CPC title

• B32B27/22

  using plasticisers · CPC title

• B32B2307/102

  Insulating · CPC title

• B32B27/306 Primary

  comprising vinyl acetate or vinyl alcohol (co)polymers · CPC title

• B32B17/10605

  Type of plasticiser · CPC title