| PATENT ASSIGNEE'S COUNTRY | USA |
| UPDATE | 10.99 |
| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | 26.10.99 |
| PATENT TITLE |
Carbamoyl substituted acetals and compositions containing the same |
| PATENT ABSTRACT |
A diacetal of a polyhydric alcohol is provided having at least one carbamoyl substituent bonded to an oxy group of the alcohol. The compound is useful as a nucleating agent in polymer resins and as a gelling agent. |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | 26.11.97 |
| PATENT REFERENCES CITED | This data is not available for free |
| PATENT CLAIMS |
What we claim is: 1. A compound comprising the addition product of (a) a diacetal formed by the condensation reaction of two moles of an aromatic aldehyde and a polyhydric alcohol having five or more hydroxyl groups; and (b) an isocyanate, whereby the isocyanate reacts with a free hydroxyl group of the polyhydric alcohol. 2. The compound of claim 1 wherein the polyhydric alcohol is selected from the group consisting of pentahydric and hexahydric alcohols. 3. The compound of claim 2 wherein the isocyanate is selected from the group consisting of aromatic, aliphatic and cycloaliphatic monoisocyanates. 4. The compound of claim 1 wherein the polyhydric alcohol is xylitol or D-sorbitol. 5. The compound of claim 4 wherein the isocyanate is selected from the group consisting of alkyl and cycloalkyl isocyanates. 6. The compound of claim 1 wherein the polyhydric alcohol is sorbitol and the isocyanate is selected from the group consisting of alkyl and cycloalkyl isocyanates. 7. The compound of claim 1 wherein a second mole of the isocyanate adds to a second free hydroxyl group of the polyhydric alcohol. 8. A compound having the formula: ##STR24## where p is 0 or 1; R.sub.1 and R.sub.2 are aromatic groups and may be the same or different; R.sub.3 and R.sub.4 are independently selected from the group consisting of --OH and --OC(O)N(R.sub.5)R.sub.6, where R.sub.5 is H, aryl, aliphatic or cycloaliphatic, and R.sub.6 is H or R.sub.5 ; and provided that at least one of R.sub.3 and R.sub.4 is --OC(O)N(R.sub.5)R.sub.6. 9. The compound of claim 8 wherein R.sub.1 and R.sub.2 are selected from the group consisting of phenyl and phenyl substituted with from 1 to 3 C.sub.1-4 alkyl, halo or C.sub.3-5 alkylene forming a carbocyclic ring with adjacent carbon atoms of the phenyl ring. 10. The compound of claim 8 wherein R.sub.6 is H. 11. The compound of claim 10 wherein p is 1. 12. The compound of claim 11 wherein R.sub.3 and R.sub.4 are --OC(O)N(R.sub.5)R.sub.6. 13. A composition comprising a thermoplastic resin having incorporated therein from 0.005 to 3 wt. % of a compound having the formula: ##STR25## where p is 0 or 1; R.sub.1 and R.sub.2 are aromatic groups and may be the same or different; R.sub.3 and R.sub.4 are independently selected from the group consisting of --OH and --OC(O)N(R.sub.5)R.sub.6, where R.sub.5 is H, aryl, aliphatic or cycloaliphatic, and R.sub.6 is H or R.sub.5, and provided that at least one of R.sub.3 and R.sub.4 is --OC(O)N(R.sub.5)R.sub.6. 14. The composition of claim 13 wherein the resin is selected from polyolefin, polyester, polyamide and poly(phenylene sulfide), syndiotactic polystyrene and polyketone resins. 15. The composition of claim 13 wherein p is 1 and R.sub.6 is H. 16. The composition of claim 15 wherein R.sub.3 and R.sub.4 are selected from --OC(O)N(R.sub.5)R.sub.6. 17. The composition of claim 16 wherein the resin is a polyolefin selected from the group consisting of polypropylene, propylene/ethylene copolymer and polyethylene. 18. The composition of claim 15 wherein the resin is a polyolefin selected from the group consisting of polypropylene, propylene/ethylene copolymer and polyethylene. 19. The composition of claim 13 wherein R.sub.5 is selected from the group consisting of cyclohexyl and isopropyl, and R.sub.6 is H. 20. The compound of claim 8 wherein R.sub.5 is selected from the group consisting of cyclohexyl and isopropyl, and R.sub.6 is H. -------------------------------------------------------------------------------- |
| PATENT DESCRIPTION |
BACKGROUND OF THE INVENTION This invention relates to carbamoyl derivatives of diacetals of polyhydric alcohols and aromatic aldehydes, which are useful as nucleating agents for polymer resins and as gelling and thickening agents for organic liquids. The use of nucleating agents to reduce the haze in articles manufactured from crystalline polyolefin resins is well known in the art. Representative acetals of sorbitol and xylitol, which have been employed as clarifying agents, include the following U.S. patents: Hamada, et al., U.S. Pat. No. 4,016,118, dibenzylidene sorbitols; Kawai, et al., U.S. Pat. No. 4,314,039, di(alkylbenzylidene) sorbitols; Mahaffey, Jr., U.S. Pat. No. 4,371,645, di-acetals of sorbitol having at least one chlorine or bromine substituent; Kobayashi, et al., U.S. Pat. No. 4,954,291, distribution of diacetals of sorbitol and xylitol made from a mixture of dimethyl or trimethyl substituted benzaldehyde and unsubstituted benzaldehyde; and Rekers, U.S. Pat. No. 5,049,605, bis(3,4-dialkylbenzylidene) sorbitols including substituents forming a carbocyclic ring. Methods for manufacturing the acetals may be found in Murai, et al. U.S. Pat. No. 3,721,682 and New Japan Chemical EP 0 497 976. Although the exact mechanism is not well understood, it is generally believed that the nucleating agent must solubilize and reform into a very fine network within the polyolefin resin. This crystalline network provides nucleation sites, which reduces the size of the spherulites formed in the resin as it cools. Small spherulites do not scatter visible light as effectively as large spherulites, so the nucleated polyolefin resin has improved clarity. The acetals may be incorporated into a thermoplastic resin as a nucleating agent by blending the acetals and powdered resin together, and then extruding the mixture. One concern that arises during processing is that the acetals can sublimate and redeposit causing "plate out". Consequently, it is often desirable to employ acetals with a relatively low volatility. As the melting point of the nucleating agent increases, however, it generally becomes necessary to extrude the resin/acetal mixture at higher temperatures. One method of using lower processing temperatures is disclosed in Mannion, U.S. Pat. No. 5,198,484; the acetals are milled to ultrafine particle size, and dissolved in the resin at below their melt temperature. Nevertheless, milling the acetals requires additional processing steps and capital investments in equipment. Further, the solubility of the acetal in the resin may become a factor at operating temperatures below the nucleating agent's melt temperature. Additional considerations in regard to the performance of the acetals as nucleating agents in polymer resins include the cost and availability of the aromatic aldehydes, organoleptics and efficacy. An alternative clarifying agent for polyolefin resin is disclosed in New Japan Chemical JP 6-256590 (1994). A polyurea containing polymethylene segments of 2 to 12 carbons was found to be an effective crystal clarifying agent at concentrations of 0.01% to 0.05%. SUMMARY OF THE INVENTION Therefore, an object of the invention is to provide a nucleating agent/gelling agent which is efficacious in a broad range of thermoplastic resins and organic liquids. Another object of the invention is to provide a carbamoyl derivative of a diacetal of an aromatic aldehyde and a polyhydric alcohol. Another object of the invention is to provide a carbamoyl derivative which is economical to manufacture and use, has low plate out and good organoleptic properties, i.e. low odor and taste transfer characteristics. A further object of the invention is to provide a novel class of compounds which can be readily tailored to achieve desired resin solubility and melt temperature. Accordingly, a carbamoyl derivative of a diacetal is provided, characterized as a diacetal formed by the condensation reaction of two moles of an aromatic aldehyde and a polyhydric alcohol having five or more hydroxyl groups, having a carbamoyl substituent bonded to an oxy group of the polyhydric alcohol. The carbamoyl substituted acetal may be used as a nucleating agent by incorporating the compound into a thermoplastic resin under conditions in which the carbamoyl acetal is melted or dissolved in the molten resin, after which the composition is allowed to cool. In another aspect of the invention, the carbamoyl acetal is blended with an organic liquid in an amount sufficient to gel or thicken the liquid. DETAILED DESCRIPTION OF THE INVENTION Without limiting the scope of the invention, the preferred embodiments and features are hereinafter set forth. Unless otherwise indicated, all parts and percentages are by weight and conditions are ambient, i.e. one atmosphere of pressure and 25.degree. C. The term "aromatic" refers to single and fused double-ring compounds having at least one unsaturated hydrocarbon ring. The term "aryl" refers to single and fused double ring unsaturated hydrocarbons. Unless otherwise specified, aliphatic hydrocarbons are from 1 to 20 carbon atoms in length, and cycloaliphatic hydrocarbons comprise from 3 to 8 carbon atoms. All of the United States patents cited in the specification are hereby incorporated by reference. The carbamoyl acetals of the present invention may be characterized as a diacetal, formed by the condensation reaction of an aromatic aldehyde and a polyhydric alcohol, wherein at least one oxy atom of the alcohol component of the acetal has a carbamoyl substituent bonded thereto. The carbamoyl radical may be "N" substituted with a group selected from aryl, aliphatic and cycloaliphatic groups, which themselves may have from 1 to 4 substituents selected from alkyl, alkoxy, halo and phenyl. Preferably, the carbamoyl radical has one N substituent selected from phenyl, alkyl and cycloalkyl groups. The polyhydric alcohol may have a second free oxy group, as with a hexahydric alcohol or higher, and a second carbamoyl substituent may be bonded to the second oxy group. The carbamoyl acetals of the present invention may be conveniently made from diacetals of pentahydric and hexahydric alcohols, preferably xylitol and D-sorbitol, respectively, and characterized by the formula: ##STR1## where p is 0 or 1, preferably 1; R.sub.1 and R.sub.2 are aromatic groups and may be the same or different, preferably R.sub.1 and R.sub.2 are selected from phenyl and phenyl substituted with from 1 to 3 C.sub.1-4 alkyl, halo and C.sub.3-5, alkylene forming a carbocyclic ring with adjacent atoms of an unsaturated hydrocarbon ring; R.sub.3 and R.sub.4 are selected from the group consisting of --OH and --OC(O)N(R.sub.5)R.sub.6 where R.sub.5 is H, aryl, aliphatic or cycloaliphatic, and R.sub.6 is H or R.sub.5, preferably H; provided that at least one of R.sub.3 and R.sub.4 is --OC(O)N(R.sub.5)R.sub.6. The carbamoyl acetal may be synthesized by the addition reaction of an isocyanate and a free hydroxyl group of a diacetal. Monoisocyanates are preferred. Suitable isocyanates may be characterized by the formula R--N.dbd.C.dbd.O, where R is aryl, aliphatic or cycloaliphatic, preferably phenyl, alkyl, or cycloalkyl, and each R may be further substituted with from 1 to 4 substituent groups selected from phenyl, alkyl, halo and alkoxy. Examples of suitable isocyanates include methylisocyanate, ethylisocyanate, propylisocyanate, isopropylisocyanate, butylisocyanate, tert-butylisocyanate, octylisocyanate, octadecylisocyanate, cyclohexylisocyanate, chloromethylisocyanate, ethoxycarbonylisocyanate, phenylisocyanate, o-tolylisocyanate and allylisocyanate. The diacetal may be reacted with a mixture of isocyanates to provide a carbamoyl acetal with two different carbamoyl substituents. Diacetals useful in the present invention may be made by the condensation reaction between two moles of an aromatic aldehyde and one mole of a polyhydric alcohol. The aromatic aldehydes are single or fused double ring aldehydes having at least one unsaturated hydrocarbon ring, and include benzaldehyde, naphthaldehyde, indan aldehyde and tetrahydronaphthaldehyde (tetralin aldehyde). The aromatic aldehydes may be unsubstituted or have from one to five substituent groups selected from C.sub.1-4 alkyl, C.sub.1-4 alkoxy, hydroxy, halogen, C.sub.1-6 alkylthio, C.sub.1-6 alkylsulfoxy, C.sub.3-5 alkylene forming a carbocyclic ring with adjacent carbon atoms on an unsaturated hydrocarbon ring, carboxyl, (C.sub.1 -C.sub.20 alkyloxy)carbonyl, (C.sub.1 -C.sub.20 alkyloxy)ethyloxycarbonyl, (C.sub.1 -C.sub.12 alkyl)phenyl, halogenated phenyl, (C.sub.1 -C.sub.12 alkoxy)phenyl, (C.sub.1 -C.sub.12 alkyloxy)ethyloxyethyloxycarbonyl and (C.sub.1 -C.sub.12 alkyloxy)ethyloxyethyloxyethyloxycarbonyl groups. Preferably, the aromatic aldehyde is selected from unsubstituted benzaldehyde, benzaldehyde having from one to three substituent groups selected from C.sub.1-4 alkyl, halogen and C.sub.3-5 alkylene forming a carbocyclic ring with adjacent carbon atoms on an unsaturated hydrocarbon ring, including p-methyl, p-ethyl, 2,4-dimethyl, 3,4-dimethyl and 2,4,5-trimethyl benzaldehyde, 5-indan aldehyde and 5', 6', 7', 8'-tetrahydro-2-naphthaldehyde. Preferred aromatic aldehydes are represented by the formula: ##STR2## wherein n is 0, 1, 2 or 3, and R is, at each occurrence, selected from C.sub.1-4 alkyl, halogen, or a three or four membered alkylene group forming a carbocyclic ring with adjacent atoms of the unsaturated parent ring. Mixtures of the aromatic aldehydes may be provided and will result in a distribution of diacetals having the same or different aromatic components, referred to as symmetric and asymmetric diacetals, respectively. The aromatic aldehydes typically react with the polyhydric alcohol to form acetals in the 1:3 and 2:4 positions. The polyhydric alcohols have five or more hydroxyl groups. The sugar alcohols represented by the formula HOCH.sub.2 (CHOH).sub.n CH.sub.2 OH, where n=3-5, have been found to be especially useful. Preferably, the polyhydric alcohol is a pentahydric or hexahydric alcohol, most preferably xylitol or D-sorbitol. The condensation reaction is typically conducted in a hydrophobic organic liquid medium in the presence of an acid catalyst, as is well known in the art. Diacetals of sorbitol and benzaldehyde and alkyl-substituted benzaldehyde, are commercially available from Milliken Chemical, a division of Milliken & Company, Spartanburg, S.C., U.S.A. The addition reaction between an isocyanate and alcohol to form a urethane is well known in the art. Preferably, a good solvent for the reactants is employed in the reaction mixture, such as a methyl pyrrolidone, in particular 1-methyl-2-pyrrolidone. The following example demonstrates the addition reaction between dibenzylidene sorbitol acetal (DBS), having two free hydroxyl groups, and cyclohexyl isocyanate. |
| PATENT EXAMPLES | This data is not available for free |
| PATENT PHOTOCOPY | Available on request |
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