Approach to heat expandable materials
AssigneeSika Technology AG
InventorsGeng Lin, Leslie Wolschleger, Nicolae Bordeanu
Life of this patent
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Abstract
A thermally expandable composition, including at least one epoxy-functional polymer, at least one thermoplastic polymer, at least one chemical blowing agent, and at least one activator, wherein the epoxy-functional polymer is present in the composition before expansion with an amount of between 30 and 75 wt.-%, based on the total composition, and the epoxy-functional polymer includes at least 300 mmol epoxy groups per kg polymer, and wherein the chemical blowing agent is able to form at least one reaction product with at least two amino groups upon thermal decomposition, and the chemical blowing agent is in the composition before expansion with an amount of between 5 and 30 wt.-%, based on the total composition.
Claims19
A thermally expandable composition, consisting essentially of:
- (a) at least one epoxy-functional polymer EP, wherein:
- (i) the at least one epoxy-functional polymer EP is present in the composition before expansion in an amount of between 30 and 75 wt.-%, based on the total composition, and
- (ii) the at least one epoxy-functional polymer EP comprises at least 300 mmol epoxy groups per kg polymer EP,
- (b) a first thermoplastic polymer P1 having a melt flow index of between 100 and 200 g/10 min and a second thermoplastic polymer P2 having a melt flow index of between 0.1 and 60 g/10 min,
- (c) at least one chemical blowing agent B, wherein:
- (i) the at least one chemical blowing agent B is able to form at least one reaction product with at least two amino groups upon thermal decomposition, and
- (ii) the at least one chemical blowing agent B is present in the composition before expansion in an amount of between 12.2 and 25 wt.-%, based on the total composition,
- (d) optionally at least one activator A,
- (e) optionally at least one additive selected from the group consisting of stabilizers, antioxidants, fillers, colorants, tackifiers, dispersion aids, homogenizers, and adhesion promoters.
Dependencies are inferred from the claim text.