Claims
- 1. A moisture-proof electrical connector for sealingly connecting transmission means therein comprising
- (a) a connector body having a receiving means for accepting and receiving a transmission means; and
- (b) a sealant composition disposed along or adjacent to the receiving means, said sealant composition comprising:
- (i) polymeric adipic acid polyester in an amount at least about 50% by weight of the composition;
- (ii) silica thickening agent dispersed in said polymer;
- (iii) organofunctional coupling agent; and
- (iv) polyfunctional bridging agent, said silica thickening agent and said coupling and said bridging agents being present in amounts sufficient to cause gelation of said composition.
- 2. The connector of claim 1 wherein said composition has a viscosity of from about 125 units to about 350 units of 0.1 mm each as measured by ASTM D217 Standard Test Methods for Cone Penetration of Lubricating Grease.
- 3. The connector of claim 1 wherein:
- (a) the concentration of said polyester is from about 80% to about 95% by weight of the composition;
- (b) said silica thickening agent comprises a hydrophilic fumed silica in an amount at least 50% by weight of the silica; and
- (c) the concentration of said silica thickening agent is from about 5% to about 15% by weight of the composition.
- 4. The connector of claim 3 wherein said organofunctional coupling agent is selected from the group consisting of (glycodioxypropyl)trimethoxysilane, hexamethyldisilizane, (methacryloxypropyl)trimethoxysilane, (epoxycyclohexyl)-ethyltrimethoxysilane and mixtures of these.
- 5. The connector of claim 4 wherein said coupling agent comprises (glycodioxypropyl)trimethoxysilane in an amount from about 0.1% to about 0.4% by weight of the composition and said bridging agent comprises triethanolamine in an amount from about 0.2% to about 0.4% by weight of the composition.
- 6. The connector of claim 3 wherein said polyfunctional bridging agent is selected from the group consisting of ethylene glycol, pentaerythritol, trimethylolpropane, triethanolamine, and mixtures of these.
- 7. A moisture-proof electrical connector for sealing leak connecting transmission means therein comprising:
- (a) a connector body having a receiving means for accepting and receiving a transmission means; and
- (b) a sealant composition having a viscosity of from about 125 units to about 350 units of 0.1 mm each as measured by ASTM D217 Standard Test Methods for Cone Penetration of Lubricating Grease disposed along or adjacent to the receiving means, said sealant composition comprising:
- (i) polymeric adipic acid polyester in an amount from about 80% to about 88% by weight of the composition;
- (ii) fully hydrophobized silica thickening agent dispersed in said polymer in an amount from about 12% to about 18% by weight of the composition;
- (iii) organofunctional coupling agent; and
- (iv) polyfunctional bridging agent, said silica thickening agent and said coupling and said bridging agents being present in amounts sufficient to cause gelation of said composition.
- 8. The connector of claim 7 wherein said composition has a viscosity of from about 180 units to about 280 units of 0.1 mm each as measured by ASTM D217 Standard Test Methods for Cone Penetration of Lubricating Grease.
- 9. The connector of claim 7 wherein:
- (a) said polyester has an average molecular weight as calculated from solution viscosity measurements of from about 1,000 to about 8,000 and comprises the reaction product of adipic acid and a lower alkylene glycol; and
- (b) said silica thickening agent comprises a fully hydrophobized fumed silica.
- 10. The connector of claim 9 wherein said lower alkylene glycol is butylene glycol.
- 11. The connector of claim 9 wherein said organofunctional coupling agent is selected from the group consisting of (glycodioxypropyl)trimethoxysilane, hexamethyldisilizane, (methacryloxypropyl)trimethoxysilane, (epoxycyclohexyl)-ethyltrimethoxysilane and mixtures of these.
- 12. The connector of claim 9 wherein said polyfunctional bridging agent is selected from the group consisting of ethylene glycol, pentaerythritol, trimethylolpropane, triethanolamine, and mixtures of these.
- 13. The connector of claim 9 wherein said coupling agent comprises (glycodioxypropyl)trimethoxysilane in an amount from about 0.02% to about 0.5% by weight of the composition and said bridging agent comprises triethanolamine in an amount from about 0.05% to about 1.0% by weight of the composition.
- 14. A moisture-proof electrical connector for sealingly connecting transmission means therein comprising:
- (a) a connector body having a receiving means for accepting and receiving a transmission means; and
- (b) a sealant composition having a viscosity of from about 125 units to about 350 units of 0.1 mm each as measured by ASTM D217 Standard Test Methods for Cone Penetration of Lubricating Grease disposed along or adjacent to the receiving means, said sealant composition comprising:
- (i) polymeric adipic acid polyester in an amount from about 85% to about 95% by weight of the composition;
- (ii) hydrophilic silica thickening agent dispersed in said polymer in an amount from about 5% to about 15% by weight of the composition;
- (iii) organofunctional coupling agent; and
- (iv) polyfunctional bridging agent, said silica thickening agent and said coupling and said bridging agents being present in amounts sufficient to cause gelation of said composition.
- 15. The connector of claim 14 wherein said composition has a viscosity of from about 180 units to about 280 units of 0.1 mm each as measured by ASTM D217 Standard Test Methods for Cone Penetration of Lubricating Grease.
- 16. The connector of claim 14 wherein:
- (a) said polyester has an average molecular weight as calculated from solution viscosity measurements of from about 1,000 to about 8,000 and comprises the reaction product of adipic acid and a lower alkylene glycol; and
- (b) said silica thickening agent comprises fumed silica.
- 17. The connector of claim 16 wherein said lower alkylene glycol is butylene glycol.
- 18. The connector of claim 14 wherein said organofunctional coupling agent is selected from the group consisting of (glycodioxypropyl)trimethoxysilane, hexamethyldisilizane, (methacryloxypropyl)trimethoxysilane, (epoxycyclohexyl)-ethyltrimethoxysilane and mixtures of these.
- 19. The connector of claim 14 wherein said polyfunctional bridging agent is selected from the group consisting of ethylene glycol, pentaerythritol, trimethylolpropane, triethanolamine, and mixtures of these.
- 20. The connector of claim 14 wherein said coupling agent comprises (glycodioxypropyl)trimethoxysilane in an amount from about 0.02% to about 0.5% by weight of the composition and said bridging agent comprises triethanolamine in an amount from about 0.05% to about 1.0% by weight of the composition.
Parent Case Info
The present application is a continuation-in-part of application Ser. No. 767,566, filed Aug. 20, 1985, now U.S. Pat. No. 4,714,801, which is in turn a continuation of application Ser. No. 620,411, filed June 14, 1984, now abandoned, both of which are assigned to the assignee of the present invention and incorporated herein by reference.
The present invention relates to sealant compositions, electrical connectors including said sealant compositions, and methods of making same. More particularly, this invention relates to sealant compositions resistant to water diffusivity and weather resistant connectors containing these compositions.
The quality and durability of electrical connections are important factors in the design of electrical systems, especially electrical systems utilized in the telecommunications industry. The quality of electrical connections is determined not only by the extent of effective electrical insulation surrounding the connection, but also the extent to which the actual connection is maintained in a moisture-free, non-corrosive environment. The existence of water at the connection site is detrimental in several respects. For example, the "crosstalk" which frequently plagues telecommunication systems is sometimes caused by moisture in the connections which provides a path for signal leakage. The presence of water also has the obvious disadvantage of fostering corrosion thus negatively impacting upon the durability of the connection. The ability of the connecting material and/or apparatus to withstand degradation in the face of environmental variations, for example, temperature cycling, also has an impact upon connection durability. A faulty connection, especially in telecommunication systems, may be expensive and time consuming to repair or replace because of inaccessibility and difficulty of identification.
Various sealant compositions have been used in electrical connectors to form sealed connections. For example, U.S. Pat. No. 3,410,950-Freudenberg, which is incorporated herein by reference, discloses open U-type or channel-type connecting devices having a sealant system. The pre-insulated connector disclosed therein has one insulating film surrounding the outside of the open U-type ferrule, the ferrule having one or more wire receiving projections on its inside surface. Sealing material is contained between the inside insulating film and the surface of the ferrule adjoining the projections. When the connector is crimped onto wires, the projections rupture the inside film layer permitting the sealing material to flow around the wires. Impregnated polyurethane foams are described as the preferred sealant material, although flowable plastic materials are mentioned as alternatives.
The sealants used with connectors of the type described above frequently have a silicone base. Although sealants of this type do repel moisture, they also have a tendency over a period of time to creep out of the connector. Their oil base has been observed to separate and to "cream" or "bleed" during storage. Furthermore, fractions of the silicone based sealants have significant vapor pressures under common ambient conditions. Fractions of the sealant, therefore, vaporize when exposed to the atmosphere and condense on nearby surfaces including switch gear contacts resulting in accelerated arcing and corrosion.
The sealant material disclosed herein has dielectric properties similar to those of silicone based sealants. The problems described above, however, are greatly reduced. The compositions of the present invention have lower water and oxygen diffusivity than silicone based sealants. The sealants generally have higher viscosities, thus greatly reducing the problem of migration, that is, creeping and extraction. The lower vapor pressures of the herein disclosed sealants greatly decrease the problem of contamination of the surrounding area.
Accordingly, it is an object of the present invention to provide sealant compositions and sealed electrical connectors which are resistant to the passage of water.
It is a further object of the present invention to provide sealant compositions and sealed electrical connections which are resistant to the passage of oxygen.
It is yet another object of the present invention to provide sealant compositions whose properties, including water sorption and viscosity, are relatively constant over a wide range of temperatures.
It is a still further object of this invention to provide sealant compositions which are resistant to creep and extraction caused by exogenous agents such as water and heat.
It is an additional object of the present invention to provide sealant compositions and sealed electrical connectors having little or no inherent tendency to cause corrosion at the connection or in the area surrounding the connection.
These and other objects of the present invention are generally satisfied by sealant compositions comprising adipic acid derived polymeric polyesters and silica. The sealant compositions of the present invention also preferably include a bridging agent to promote gelation of the compositions and stability of the gel structure. According to certain embodiments of the present invention, the mixture further comprises wetting or dispersing agents for promoting dispersion and homogenization of the silica. A surfactant may also be included in certain embodiments to promote wetting and dispersion of the silica. The compositions may also optionally include antimicrobial agents, corrosion inhibitors and/or antioxidants.
The objects of the present invention are also generally satisfied by connectors which incorporate the compositions of the present invention. According to one preferred embodiment, the connector includes a receiving means for accepting and receiving a transmission means. The transmission means provides means for transmitting electrical current or signals, such as an electrical wire. A sealant according to the present invention is disposed within or adjacent to the wire receiving means, the sealant being substantially flowable but substantially non-migratory under crimping pressure.
The objects of the present invention are also generally satisfied by methods of manufacturing electrical connectors which incorporate the compositions of the present invention. According to one preferred embodiment, the manufacturing methods require providing a connector body having a receiving means for accepting and receiving a transmission means. The methods further require dispensing a sealant according to the present invention into said connector body.
US Referenced Citations (13)
Non-Patent Literature Citations (2)
| Entry |
| Damusis, Sealants, Reihold Publishing Corp., New York, N.Y., 1967, pp. 116-169. |
| Iler, The Colloid Chemistry of Silica and Silicates, Cornell University Press, Ithaca, N.Y., 1955, pp. 169 and 170. |
Continuations (1)
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Date |
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| Parent |
620411 |
Jun 1984 |
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Continuation in Parts (1)
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767566 |
Aug 1985 |
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Patent Grant
5004869
