Curable composition and cured product thereof
The present invention provides a sealant composition that includes a reactive silyl group-containing organic polymer, and gives a cured product having a low modulus and not having wrinkles or cracks on the surface even though the sealant includes as a curing catalyst a tetravalent tin compound, which is presumed to reduce recovery. The sealant composition is a one-component curable sealant composition including: a linear organic polymer (A) having a number average molecular weight of 11,000 to 30,000, and having an ethanol-elimination reactive silyl group at a molecular terminal; a tetravalent tin compound (B); and a plasticizer (C).
1. A one-component curable sealant composition, comprising:
100 parts by weight of a linear organic polymer (A) having a number average molecular weight calculated from the amount of hydroxy groups of 11,000 to 30,000, and having a triethoxysilyl group at a molecular terminal;
0.5 to 10 parts by weight of a tetravalent tin compound (B);
70 to 200 parts by weight of a plasticizer (C); and
a silane coupling agent
comprising a mixture of triethoxyvinylsilane and trimethoxyaminosilane.
2. The one-component curable sealant composition according to claim 1 , wherein the tetravalent tin compound (B) is at least one of a dibutyltin compound and a dioctyltin compound.
3. The one-component curable sealant composition according to claim 1 , wherein the component (A) comprises at least one of a polyoxyalkylene polymer and a polyacrylate polymer as its backbone.
4. The one-component curable sealant composition according to claim 1 , wherein the component (A) has a number average molecular weight calculated from the amount of hydroxy groups of 13,000 to 25,000.
5. The one-component curable sealant composition according to claim 1 , wherein the organic polymer (A) is derived from a polyoxyalkylene polymer formed by ring-opening addition polymerization of an alkylene oxide in the presence of a double metal cyanide complex catalyst.
6. The one-component curable sealant composition according to claim 1 , wherein the organic polymer (A) is a polyoxypropylene polymer.
7. The one-component curable sealant composition according to claim 1 , wherein the organic polymer (A) has 1.0 to 2.0 ethanol-elimination reactive silyl groups per molecule on average.
8. The one-component curable sealant composition according to claim 1 , which gives a cured product having a modulus at 100% elongation, measured by a method defined in ISO 8339, of 0.4 MPa or lower.
9. A one-component curable sealant for buildings, comprising the curable sealant composition according to claim 1 .
10. A one-component curable sealant for working joints, comprising the curable sealant composition according to claim 1 .
11. A one-component curable sealant for curtain walls, comprising the curable sealant composition according to claim 1 .
12. A one-component curable sealant for balcony window frames, comprising the curable sealant composition according to claim 1 .
13. A one-component curable sealant for stone materials, comprising the curable sealant composition according to claim 1 .
14. A one-component curable sealant for bridges, comprising
the curable sealant composition according claim 1 .
15. A cured product of the one-component curable sealant composition according to claim 1 .
16. The one-component curable sealant composition according to claim 1 , wherein the number of the triethoxysilyl groups in the organic polymer (A) per molecule of the polymer on average is 1.2 to 1.6.
17. The one-component curable sealant composition according to claim 1 , which comprises 70 to 150 parts by weight of the plasticizer (C) for 100 parts by weight of the organic polymer (A).