EXPANDABLE COMPOSITION COMPRISING A CYCLIC CARBONATE AND A BASE

Abstract

The present application relates to a thermally expandable composition which comprises at least one organic compound comprising at least two cyclic carbonate groups, at least one compound having at least one functional group with a pKa value of greater than 3 and at least one base, to shaped bodies which contain said composition, and to a method for sealing and filling voids in components, for strengthening or reinforcing components, in particular hollow components, and for bonding mobile components using shaped bodies of this type.

Claims

1. A thermally expandable composition comprising (1) at least one organic compound comprising at least two cyclic carbonate groups, (2) at least one compound having at least one functional group having a pKa value of greater than 3, and (3) at least one base.

2. The thermally expandable composition according to claim 1, wherein the organic compound is a polyether and/or polyester, to which at least two cyclic carbonate groups are bonded.

3. The thermally expandable composition according to claim 1, wherein the at least one organic compound is a cyclic organic carbonate of Formula (I) ##STR00007## being a single bond or a double bond, where if the ring contains a double bond, R.sub.1 is not bonded by an exo double bond, but rather by a single bond, and vice versa, and R.sub.1 is a linear or branched, substituted or unsubstituted alkyl, linear or branched, substituted or unsubstituted heteroalkyl, linear or branched, substituted or unsubstituted alkenyl, linear or branched, substituted or unsubstituted alkinyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, or C(O)R.sup.a, where R.sup.a is H, a linear or branched, substituted or unsubstituted alkyl, linear or branched, substituted or unsubstituted heteroalkyl, linear or branched, substituted or unsubstituted alkenyl, linear or branched, substituted or unsubstituted alkinyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, a is an integer from 0 to 5, and r is a natural number from 2 to 10.

4. The thermally expandable composition according to claim 3, wherein the at least one organic compound is a cyclic organic carbonate of Formula (II) ##STR00008## , a and r being as defined above and R.sub.2 being defined as R.sub.1.

5. The thermally expandable composition according to claim 4, wherein the at least one organic compound is a cyclic organic carbonate of Formula (III) or (IV), ##STR00009## each b and c being, independently of one another, a natural number from 1 to 5, and each X being independently selected from the group consisting of O, S and N.

6. The thermally expandable composition according to claim 5, wherein the at least one organic compound is a cyclic organic carbonate of Formula (V) or (VI) ##STR00010##

7. The thermally expandable composition according to claim 1, wherein the at least one base is a nitrogen-containing base.

8. The thermally expandable composition according to claim 7, wherein the at least one base is selected from the group consisting of 1-methylimidazole, 2,4-ethylmethylimidazole (EMI), 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[3.4.0]non-5-ene (DBN) and mixtures thereof.

9. The thermally expandable composition according to claim 1, wherein the thermally expandable composition comprises, based on the binder system (total weight of the composition prior to expansion without fillers), 20 to 90 wt. % of the at least one organic compound comprising at least two cyclic carbonate groups.

10. The thermally expandable composition according to claim 1, wherein the at least one functional group of the at least one compound is selected from OH, NH.sub.2 and/or SH groups.

11. The thermally expandable composition according to claim 1, wherein the at least one compound has at least two functional groups selected from OH and/or SH groups, having a pKa value of greater than 5.

12. A shaped body, wherein the shaped body comprises a thermally expandable composition according to claim 1.

13. A method for sealing and filling hollow spaces in components, for strengthening or stiffening components, and/or for bonding movable components, using a thermally expandable composition according to claim 1.

14. A method for sealing and filling hollow spaces in components and for strengthening or stiffening components, comprising steps of: inserting a shaped body according to claim 12 into a hollow space of a component; and heating the shaped body to a temperature of greater than 30 C., such that the thermally expandable composition expands and seals, fills, strengthens or stiffens the component.

15. A method for sealing and filling hollow spaces in components, for strengthening or stiffening components, and/or for bonding movable components, contacting the component(s) to be sealed, filled, strengthened, stiffened and/or bonded with the shaped body according to claim 12 and heating the shaped body to a temperature sufficient to activate the thermally expandable composition such that the thermally expandable composition expands and seals, fills, strengthens, stiffens and/or bonds the component(s).

16. The use of a shaped body according to claim 12 for acoustically sealing hollow spaces in components and/or for sealing hollow spaces in components against water and/or moisture, or for strengthening or stiffening components.

Description

EXAMPLES

[0128] Synthesis of an Organic Carbonate from Epoxide and Carbon Dioxide

[0129] Tetrabutylammonium iodide was obtained from Acros. Epoxides DER 331 and DER 749 were obtained from Dow Chemicals.

[0130] The carbonate was prepared using a two-part 1 liter glass reactor equipped with a hollow mechanical stirrer and a thermometer. The temperature was kept constant by connecting the thermometer to a hot plate. Dry ice (CO.sub.2) was added to another 1 liter round flask. The released gas was introduced into the main reactor through a polyethylene tube via the hollow stirrer. The epoxide was added into the reactor together with the corresponding catalyst (10 wt. % of the epoxide) and heated at 140 C. while stirring constantly. Bubbles could be observed in the epoxy mixture.

[0131] The 1 liter round flask was filled with dry ice every 4-5 hours. After 2-3 days, the mixture became white and highly viscous. At this time, the reaction mixture was cooled. It was possible to obtain the carbonates of DER 331 (product of epichlorohydrin with bisphenol A) and DER 749 (product of epichlorohydrin and tetramethylolmethane) as the product.

[0132] The synthesis of an organic carbonate starting from polyfunctional epoxides using tetrabutylammonium iodide as a synthesis catalyst is shown by way of example in the following diagram:

##STR00006##

Expandable Compositions

[0133] The expandable compositions were obtained by mixing the constituents listed in the following table (in parts by weight), the base being added last. The expansion and curing was then carried out at 180 C. for 60 min.

TABLE-US-00001 Example 1 2 3 4 5 6 7 DER 331 - carbonate 33.6 54.81 57 57 33 DER 749 - carbonate 14.0 33 DER 331 8.4 23.6 22 22 TMPMP 30 30 42 42 Phenol novolac 24.2 27.5 27.5 Cab-o-Sil TS 720 2.5 2.5 2.0 2.5 2.5 (pyrogenic silicic acid) Barium sulfate 24.5 11.69 15.0 11.7 11.7 Monarch 580 (carbon 1.0 Glass fibers (~2 mm long) 10.0 Glass hollow spheres 7.0 2-ethyl-4-methylimidazole 1 1 Sodium hydride (35% on 1 mineral oil) Sodium hydroxide 1 (finely ground) 1,1-dimethyl urea 3.2 3.3 3.3 TMPMP: Trimethylolpropane tris(3-mercaptopropionate)

[0134] The resulting foams are characterized by a high, achievable expansion rate. Furthermore, the foams based on cyclic organic carbonates are characterized by very clean decomposition. It was not possible to detect any decomposition products from the carbonate.