There are various methods for joining or splicing communication cable ends together. In so doing, there are many important considerations such as the use of compatible materials, how many cables are being spliced, is the spliced cable to be buried in soil, immersed in water or suspended in the air, what heat source is required to make the joint, i.e., flammable gasses, will the splice need to be reopened and remade without interruption of working circuits, will the joint have sufficient mechanical strength and is the cost feasible? Communication cables are typically constructed of a conductor bundle, surrounded by a metal strength and interference sheathing and an outer protective coating, typically of a low surface energy material such as polyethylene. When such cables are spliced and rejoined, the strength and integrity of the rejoined cable is critical. An enclosure or a closure body is used to sealingly surround the splice. The closure body is also typically formed of a low surface energy material.

One persistent problem in the use of splice closures involves the need for a complete seal about the splice or closure body. Many prior art splice closures accomplish sealing by providing a complex array of nuts and bolts, clamps, gaskets and heat shrink tubing, as well as potting gels and resins, in various combinations.

Besides the fact that these closure methods require significant assembly time, the closures still often suffer leaks or ruptures, particularly along their seals. This problem is even more acute at the end seal where the closure is sealed to the cable jacket, and where even the slightest defect can result in the migration of moisture

along the jacket or the inner surface of the closure. A lack of a complete (hermetic) seal can also be particularly detrimental for pressurized closures.

Although these seals may be strengthened by the use of adhesives, the adhesive bonds formed are normally weak due to the low surface energy of the polyethylene material of the closure, the end seals and cables. End seals can be used with a fusion bond and with hot melts as an alternative bonding material. Hot melt is placed between the resistance wires, and the wires are heated to form a bond between the cables and the end seal surfaces. Hot melt bonding can be used with different end seal materials such as foams, elastomers and thermoplastics, but the bond strength is weaker than a fusion bond seal. Communication, electrical, and fiber optic cables must be periodically spliced for any of a number of different reasons well known in the art. Once the splice has been made, it must be enclosed within a closure to protect it from environmental elements that may be detrimental to the integrity of the splice. Occasionally, these closures must be re-entered and the cables re-spliced.

Splices, however, may be any of a number of different sizes and it is not economical or feasible to provide and make available a closure for every splice size that may be created. To resolve this problem, closure extensions have been developed which may be appended to closures so that a closure may be assembled which may enclose a splice of any size.

A present drawback associated with such closure extensions is that they are typically fabricated from materials, as previously mentioned, having low energy surfaces, such as polyethylene, polypropylene, or an inclusive co-polymer. Because conventional adhesives (such as epoxy) will not adhere well to low energy surfaces, they may not be used to bond closure extensions together. Therefore, more expensive and complicated techniques must be implemented for sealing and bonding closure extensions together, such as melting and thermally fusing the closure extensions together at their interface, or mechanically coupling them together.

Adhesive bonding or the achievement of adhesion of coatings to low surface energy polymeric materials has been a technological problem since the inception of the use of such materials in industry. There are many descriptions of the problems with the adhesive bonding of low energy surfaces. The difficulty with adhesive

bonding of such materials stems, in part, from the fact that these materials are deemed to be "van der Waals" solids. That is, the primary force for cohesion that is available between polymer chains is that due to van der Waals or "dispersion" forces.

Low surface energy materials derive their strength from molecular entanglements, cross-linking, crystallization or some combination of these. The surface energy of a polymer is a reflection of the forces which hold the chains together and is therefore low for these materials. Examples of low surface energy polymers are polytetrafluoroethylene, polyethylene, polypropylene, silicones, etc.

One criterion for adhesive bonding is that the adhesive must come into intimate contact with the substrate. That is, the adhesive must completely "wet" the substrate. Low surface energy polymers are very difficult to wet by polar liquids because the polar liquids have a surface energy that is higher than that of the substrate. Most high strength adhesives are polar materials and hence their surface energy is too high to wet the surface of some polymers. If the surface is incompletely wet by an adhesive, there is a greater chance for interfacial voids and hence a weaker bond.

Another criterion for adhesive bonding is that the surface must be free of weak boundary layers. Commercial plastics usually contain a substantial amount of additives such as stabilizers and flow control agents. Also, with free radically polymerized materials, there is also a substantial fraction of low molecular weight polymer in addition to the high molecular weight portion. In general, these low molecular weight fractions exude to the surface and form weak boundary layers.

These layers must be removed before the plastic can be effectively bonded or coated.

There is a substantial science and technology developed around the surface preparation of low surface energy plastics for adhesive bonding or coating. The methods which have been developed include flame treatment, corona discharge treatment, plasma treatment, oxidation by ozone, oxidation by oxidizing acids, sputter etching as well as coating with higher surface energy materials. This last method is also known as "priming" and may have to be preceded by one of the physical methods (e.g. corona discharge treatment) in order to have the primer adhere well to the surface.

In general, the surface preparation methods described above act to increase the surface energy of the polymer and/or eliminate weak boundary layers and may also increase surface roughness. The surface energy of these plastics is usually increased by the introduction of oxidized species into the surface. The elimination of weak boundary layers may take place by crosslinking and/or ablation of the exuded species. There is usually a trade-offbetween the oxidation process and the weak boundary layers removal process since over-oxidized materials may themselves form a weak boundary layer.

Very few of the methods described in the literature are useful for a wide range of plastics. In general, the treatment method or the priming means is usually quite specific for the type of plastic used. This is a severe limitation for the general user of adhesive bonding since many of the physical methods of surface treatment require substantial capital investment. Thus, there is a need for a simple, easy to use adhesive bonding method that is capable of adhering, without priming, to a wide range of plastics including those classed as "low surface energy" plastics.

An efficient, effective means for adhesively bonding low surface energy plastic substrates such as polyethylene and polypropylene has long been sought for the assembly and repair of cable splice closures. Typically, such assembly and repair is performed in the field. Consequently, there has been a considerable and long felt need for a simple, easy to use adhesive that can readily and effectively bond mating cable splice closure surfaces together as well as bonding communication cables to the end seals and bonding the end seals to the closure.

While an adhesive that can bond low surface energy plastics is advantageous, the commercial utility of such an adhesive would be enhanced if the components of the adhesive were combined in a convenient mix ratio and could be easily carried to a job site and readily applied using conventional adhesive dispensers without the need for laborious pre-mixing of the various components of the adhesive. Thus, there is not only a need for an adhesive that can bond low surface energy plastics, but a need for such an adhesive that is pre-blended and can be easily carried and readily applied without a material reduction in storage stability or performance.

Unfortunately, a suitable solution to the problems associated with varying the

size of closures, ease of installation, seal integrity and strength, has not been satisfactorily addressed by the prior art. Therefore, what is needed is an apparatus and a method for sealing cable splice closures with a low surface energy adhesive. It is also highly desirable to vary the size of such closures, modularly configured for protecting cables by the use of low surface energy materials bonded together by a low surface energy adhesive.

Summarv of the Invention The present invention accordingly, provides an apparatus and method for sealing cable splice closures and for varying the size of such closures, modularly configured, for protecting cables by the use of low surface energy materials bonded together by a low surface energy adhesive. To this end, a variable size cable closure includes a sectioned closure housing formed of a low surface energy plastic material and has joint surfaces formed on each section of the closure. The joint surfaces are configured to define adjacent sections of the housing, the adjacent sections being separable at the joint surfaces and reattached to remaining sections and added sections of the closure housing. Each joint surface is attached to a mating joint surface by a low surface energy adhesive.

A principal advantage of the present invention is that cable closure housings can be opened, modified in size by adding or removing sections of the original housing, then closing the housing by sealing the edges of the modified housing with an adhesive having improved bonding strength for use with low surface energy materials. The strength of the bond is substantially the same as the strength of the original material.

Brief Description of the Drawings Fig. 1 is an isometric view illustrating an embodiment of a cable closure housing.

Fig. 2 is an isometric view illustrating the closure housing of Fig. 1 with a cover portion partially removed.

Figs. 3-8 are diagrammatic views illustrating embodiments of various modified cable closures.

Fig. 9 is a partial cross-sectional side view illustrating an embodiment of a

bonded joint.

Fig. 10 is an isometric view illustrating an embodiment of a closure housing.

Fig. 11 is a diagrammatic side view illustrating an embodiment of a section of a closure housing.

Fig. 12 is a partial cross-sectional side view illustrating an embodiment of a bonded joint.

Fig. 13 is a partial cross-sectional side view illustrating an embodiment of a section of a closure housing.

Fig. 14 is an isometric view illustrating an embodiment of a closure housing.

Fig. 15 is an isometric view illustrating an embodiment of a closure housing.

Fig. 16 is a partial end view of the closure housing of Fig. 15.

Fig. 17 is a partial end view illustrating an embodiment of a sleeve for closing a closure housing.

Figs. 18-20 are partial cross-sectional end views illustrating embodiments of terminal boxes mounted on closure housings.

Fig. 21 is an isometric view illustrating an embodiment of a cable closure housing.

Fig. 22 is an isometric view partially illustrating an embodiment of a cable closure housing.

Fig. 23 is an isometric view partially illustrating an embodiment of a cable closure housing.

Fig. 24 is a partial cross-sectional side view illustrating an embodiment of bonded flanges of closure housing sections.

Fig. 25 is an isometric view partially illustrating an embodiment of a cable closure housing.

Fig. 26 is a partial cross-sectional side view illustrating an embodiment of bonded flanges of closure housing sections.

Fig. 27 is a partial cross-sectional side view illustrating an embodiment of bonded flanges of closure housing sections.

Fig. 28 is a partial cross-sectional side view illustrating a trimmable section of a closure housing.

Fig. 29 is a partial cross-sectional side view illustrating an embodiment of bonded edges of closure housing sections.

Fig. 30 is an isometric view illustrating a portion of a closure housing including a heating element for curing adhesive.

Description of the Preferred Embodiment A sectioned closure housing 10, Fig. 1, is formed of a low surface energy material. Housing 10 is a generally tubular dome enclosure of a sufficient height to accommodate a number of spliced cables 12 extending from a pedestal 14, and entering into housing 10. The housing 10 may be manufactured in any suitable way such as injection molding or blow molding, particularly by one piece injection molding of polyolefin materials such as polyethylene or polypropylene. Housing 10 includes a first section 16 and a second section 18. First section 16, Fig. 2, includes an open base 20 and a shoulder 22. Second section 18 is connected to first section 16 at shoulder 22 and also includes a closed distal end 24. Second section 18 is tapered at wall 19 between the connection at shoulder 22 and distal end 24.

Adjacent sections 16, 18, Fig. 3, may be separated by cutting through housing 10 at shoulder 22. Thus, ajoint surface 26 defines an end of section 16 and ajoint surface 28 defines an end of section 18. A portion 30 of second section 18 adjacent shoulder 22 is separated and removed by cutting through housing 10 at a cut line A to form a remaining portion 34. Ajoint surface 32, Fig. 4, on remaining portion 34 is attachable to first section 16 and reattached by a bead of low surface energy adhesive 33. Adhesive 33, as described herein, readily bonds with low surface energy plastics and is an acrylic monomer including organoborane amine complexes. Due to the taper of second section 18, joint surface 32 may be insertable into first section 16.

Alternately, a portion 36, Fig. 5, of second section 18, adjacent end 24, is separated and removed by cutting through housing 10 at a pair of cut lines B and C. In this case, a pair ofjoint surfaces 38, 40, on remaining portions 42, 44, respectively, are abutted and reattached with the low surface energy adhesive 33, see Fig. 6. Further, a cut line such as illustrated at D in Fig. 7, can be made in second section 18 and an extension piece 46, Fig. 8, added by applying the low surface energy adhesive 33 at abutting joints 48, 50. To aid in stabilizing or maintaining a bond line 52, Fig. 9,

during curing of adhesive 33, a strip of tape 54 or the like, can be positioned to engage adjacent sections 10a, 10b, of housing 10.

Housing 100, Fig. 10, may be configured as a substantially cylindrical section 102 having opposite ends 104, 106. A first joint 104a is formed on end 104 and a second reduced diameter joint 106a is formed on end 106. An adjacent cylindrical section 108 may also be configured as substantially cylindrical and have opposite ends 110, 112 including a first joint 11 Oa and a second reduced diameter joint 1 12a, respectively, Sections 102, 108 may or may not include a lengthwise slit, only one of which, 102a is shown. Although not shown, well known end seals may be used to provide sealed cable ports at opposite ends 104, 106 of cylindrical housing 100.

Section 102, Fig. 11, is illustrated as having the first joint 104a having a first diameter D1 and the second joint 106a having a second reduced diameter D2, less than D1. Section 108 may be similarly configured so that joint 106a, Fig. 12, of section 102 can be telescopingly fitted into engagement with second joint 1 10a of section 108.

In addition, each section 102, 108 may include a reduced diameter portion 114, Fig. 10. By cutting through section 102 of housing 100, for example, adjacent reduced diameter portion 114, Fig. 13, a new joint can be created. For example, a cut made at cut line E will result in a shortened length of section 102 into portions F and G, each portion including a joint having a diameter D1 and another joint having a diameter D2 as discussed above. These shortened length portions F and G, may be removed from existing housings to reduce the overall length, or may be added to housings to increase their overall length.

Where section 102 is slit at 102a, Fig. 10, adjacent severed edges el and e2 are formed. These edges may be engaged and secured with a bead of adhesive 33 extending along edges el and e2, Fig. 14. Cable ties 115, or the like, may be used to exert a mechanical force to maintain slit 102a closed during the curing process for adhesive 33. Alternatively, a housing 116, Fig. 15, may include a pair of lengthwise slits 118, 120 along the length thereof each slit having severed edges. One of the slits 118, for example, may include a strip 122, Fig. 16, of low surface energy material attached to respective edges e3, e4 by adhesive 33, thus forming a living

hinge 124 for moving a first portion 1 16a of housing 116 relative to a second portion 1 16b. Housing 116 may be of a single wall construction as shown or a double wall construction, not shown. Slit 120 may be secured closed by adhesive 33 and cable ties, not shown, in the manner described above and illustrated in Fig. 14. Also, slit 120 may be secured with the assistance of an elastomer sleeve 126, Fig. 17. Sleeve 126 may be secured to an edge e5 whereby a pocket 128 of sleeve 126 receives edge e5 and adhesive 33 is provided in pocket 128. Also, an edge e6 is adhered to a surface 130 of sleeve 126. In this manner, sleeve 126 provides a mechanical and adhesive retainer for closing overlapped edges e5 and e6 of slit 120, and also provides for a substantially smooth inner surface 131 on housing 116.

Occasionally, it is desirable to mount a terminal box 134 on outer surface 131 of housing 116, for example. Typically, terminal boxes 134 are mounted by using standard hardware such as clamps, bolts, etc. However, the bonding strength of adhesive 33 provides a useful mounting for a terminal box 134 without hardware.

This can be accomplished by providing an adhesive well 132, Fig. 18, 132a, Fig. 19 and 132b, Fig. 20. The well can provide a pocket for retaining adhesive 33 and a bond can be established between housing 116 and terminal box 134. Also, terminal box 134, Fig. 20, may include a protruding member 136, which may be in the form of a rib or a plurality of extensions which protrude into a receptacle 138 formed in housing 116 and including the adhesive 33.

A re-enterable sectioned closure housing may be in a rectangular form such as housing 140, Fig. 21, formed in half sections 142, 144. One of the half sections 142 includes a flange 146 for mating engagement with a flange 148 of half section 144.

The flanges 146, 148 are typically held together by well known hardware including, clamps, bolts, etc. The half sections are sealingly engaged by having a well known resilient gasket 141 provided in a groove (not shown) between mating flanges 146, 148. One or both ofthe half sections 142, 144 may include, for example, cable ports 150 such as those illustrated in Fig. 21 and which extend from an end 144a and from an opposite end 144b of half section 144. In this manner, cables may enter and exit housing 140 and a splice may be sealingly protected within housing 140 and available for re-entry when desired. Also, if desired, a no access seal can be obtained by

applying a bead of adhesive between mating flanges 146, 148 rather than a gasket and clamp arrangement as described. Although not shown, well known end seals may be used to provide sealed cable ports at opposite ends 144a, 144b of rectangular housing section 144.

A spacer extension unit 152, Figs. 21 and 22, may be provided between half sections 142, 144 to form an expanded housing 140a. Spacer extension unit 152 includes flanges 154, 156. Flange 154 can be matingly engaged with flange 148 of half section 144, and flange 156 can be matingly engaged with flange 146 of half section 142. For re-entry into housing 140a, flanges 148, 154 may be held together by hardware and include a resilient sealing gasket therebetween as described above.

Since re-entry is available at flanges 148, 154, flanges 146, 156 may be sealed by applying a bead of adhesive 33, Fig. 22, therebetween. Further, a complete no-access seal may. be accomplished, if desired by providing a bead of adhesive 33 between flanges 148, 154 and between flanges 146, 156.

Another way to extend the size of a rectangular sectioned closure housing includes an end to end abutment of half closure portions 158, 160, Fig. 23, to form an expanded housing, only a portion of which is illustrated since the other half portion (not shown) is identical. A first part 158 of the half closure portion includes cable ports 157 at an end 158a and an opposed abutment surface 158b. A second part 160 of the half closure portion includes cable ports 159 at an end 160a and an opposed abutment surface 160b. Abutment surfaces 158b, 160b, Fig. 24, are connected at internal flanges 162, 164, respectively, by a bond utilizing adhesive 33 in an adhesive well 165 formed by a void between the abutting flanges 162, 164. However, internal flanges 162 do not extend to housing flanges 158c, 160c, Fig. 23, which are butt welded at a seam 161 using adhesive 33. Alternatively, a center extension 166, Fig.

25, can be positioned between first part 158 and second part 160, and interconnected by means of external flanges 168, best illustrated in Figs. 26, 27. In Fig. 28, flanges 168a and 168b abut forming an adhesive well 170 for retaining a bead of adhesive 33 for bonding flanges 168a and 168b together. Flanges 168a, 168b, being external flanges, may extend along housing flanges 158c, 166c, 160c, as illustrated in Fig. 25.

Alternatively, external flanges 168a, 168b may be discontinued at housing flanges

158c, 166c, 160c, which can be butt welded at seams (not shown) but similar to seam 161, Fig. 23, using adhesive 33 as mentioned above. In Fig. 27, flanges 168c and 168d abut to form a void defining an alternate adhesive well 172 for retaining a bead of adhesive.33 for bonding flanges 168e and 168d together. In Fig. 28, a preformed closure half 174 includes a section 174a which is trimmable at cut lines T so that when section 174a is removed from closure half 174, trim flanges 168e and 168f remain to be abutted to form well 173, similar to flanges 168c, 168d described above and illustrated in Fig. 27. In the event that flanges, either internal or external, are not desired, a pair of wall portions 176a, 176b may be abutted by the use of an "H" strip 178, Fig. 29 including a pair of opposed closed end grooves 180a, 180b formed back-to-back to receive wall portions 176a, 176b. Adhesive 33, retained in grooves 180a, 180b, bonds strip 178 to the wall portions 176a, 176b.

The use of adhesives in the utility and communications industries has not been widely accepted, primarily due to the slow cure of adhesives at cold temperatures.

To effectively address this issue, the concept of a resistive heating element 182, Fig.

30, in conjunction with adhesive 33 has been developed. This concept involves the use of resistive heating element 182, powered by a portable energy source to assist in curing a bead of adhesive 33 set on a mating surface 184 of a mating flange 186 of one-half portion of a cable splice closure body 188, the other half portion of the closure body 188 not being shown. This is similar to the configuration shown in Figs.

21 and 22.

In theory, any form of resistive heating element 182 may be used to aid in curing adhesive 33 by embedding the element 182 into the flange 186, on the surface 184 of flange 186 or into adhesive bead 33. Using a direct current (DC) power supply (not shown) and nichrome based heating element 182, curing of adhesive 33 can be enhanced.

Material selection for the end seals and cable closures of the present invention requires good bonding capabilities to provide proper sealing as well as providing resistance to contamination, moisture and pressure. Bonding of surfaces to be sealed involves bonding of adhesive 33 to polyethylene cable jackets and to end seal bodies, cable closure bodies and trimmable washers which may be used. As such, polyolefin

and polyolefin elastomers are suitable materials for the washers, end seal bodies and cable closure bodies.

Material selection for the adhesive 33 utilizes polymerizable acrylic compositions that incorporate polymerization initiator systems based on organoborane amine complexes. The compositions are particularly useful as sealants and/or encapsulants for use with splice enclosures and the like, especially those which are manufactured from low surface energy materials (e.g. polyethylene, polypropylene, polytetrafluoroethylene, etc.) or which are used with cables sheathed with such materials.

Broadly, the polymerizable compositions comprise a polymerization initiator system and at least one acrylic monomer capable of free radical polymerization. The polymerization initiator systems comprise organoborane amine complex and a material that is reactive with the amine for liberating the organoborane. The organoborane component of the complex initiates free-radical polymerization of acrylic monomer to form an acrylic polymer that can be useful as a sealant or encapsulant. To stabilize the organoborane against premature oxidation, it is complexed with amine. The organoborane is liberated from the complex by reacting the amine portion of the complex with the amine-reactive material.

Useful organoborane amine complexes may be readily prepared using known techniques and preferably have the following general structure where R1 is an alkyl group having 1 to 10 carbon atoms, and R2 and R3 are independently selected from alkyl groups having 1 to 10 carbon atoms and phenyl- containing groups. More preferably, R1, R2 and R3 are alkyl groups having 1 to 5 carbon atoms such as methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, and pentyl.

Most preferred are complexes in which R1, R2 and R3 are each ethyl groups.

The value of v is selected so as to provide an effective ratio of primary amine nitrogen atoms to boron atoms in the complex. The primary amine nitrogen atom to

boron atom ratio in the complex is broadly about 1:1 to 4:1. Preferably, however, the ratio is about 1:1 to 2: 1, more preferably about 1:1 to 1.5:1, and most preferably about 1:1. A primary amine nitrogen atom to boron atom ratio of less than 1:1 could leave free organoborane, a material that tends to be pyrophoric. At primary amine nitrogen atom to boron atom ratios in excess of 2:1, the practical utility of the complex diminishes as the amount of complex that must be employed becomes larger.

"Am" represents the amine portion of the complex and may be provided by a wide variety of materials having at least one amine group, including blends of different amines. More preferably, "Am" is a polyamine (a material having two or more amine groups). While polyamines having two to four amine groups are especially preferred, polyamines with two amine groups (i.e., diamines) are most preferred.

"Am" may be a primary or secondary monoamine, such as those represented by the structure: wherein R4 and R5 are independently selected from the group consisting of hydrogen and alkyl groups having 1 to 10 carbon atoms, and alkylaryl groups in which the amine group is not directly attached to the aryl structure. Particular examples of these amines include ammonia, ethylamine, butylamine, hexylamine, octylamine, and benzylamine.

The amine may also be a polyamine such as those described by the structure H2N-R6-NH2 in which R6 is a divalent, organic radical comprised of an alkyl, aryl or alkylaryl group. Preferred among these materials are alkane diamines which may be branched or linear, and having the general structure: in which x is a whole number greater than or equal to 1, more preferably about 2 to 12, and R7 is hydrogen or an alkyl group, preferably methyl. Particularly preferred

examples of alkane diamines include 1 ,2-ethanediamine, 1,3 -propanediamine, 1,5- pentanediamine, 1,6-hexanediamine, 1,12-dodecanediamine, 2-methyl-1,5- pentanediamine, 3-methyl-1,5-pentanediamine, and isomers ofthese materials. While alkane diamines are preferred, other alkyl polyamines may be used such as triethylene tetraamine and diethylene triamine.

Useful polyamines may also be provided by a polyoxyalkylenepolyamine.

Polyoxyalkylenepolyamines suitable in making complexes may be selected from the following structures: H2NR8(R9O)w (Ri0O)x-(R9O)y R8M{2 (i.e., polyoxyalkylene diamines); or [H2NR8-(R9O)w]z Ri 1.

R8, R9 and R10 are alkylene groups having 1 to 10 carbon atoms and may be the same or may be different. Preferably, R8 is an alkyl group having 2 to 4 carbon atoms such as ethyl, n-propyl, iso-propyl, n-butyl or iso-butyl. Preferably, R9 and R10 are alkyl groups having 2 or 3 carbon atoms such as ethyl, n-propyl or iso- propyl. R 1 is the residue of a polyol used to prepare the polyoxyalkylenepolyamine (i.e., the organic structure that remains if the hydroxyl groups are removed.) R11 may be branched or linear, and substituted or unsubstituted (although substituents should not interfere with oxyalkylation reactions).

The value of w is 3 1, more preferably about 1 to 150, and most preferably about 1 to 20. Structures in which w is 2, 3 or 4 are useful too. the value of x and y are both 3 0. The value of z is > 2, more preferably 3 or 4 (so as to provide, respectively, polyoxyalkylene triamines and tetraamines). For the polyoxyalkylene, molecular weights of less than about 5,000 may be used, although molecular weights of about 1,000 or less are more preferred, and molecular weights of about 250 to 1,000 are most preferred.

Examples of particularly preferred polyoxyalkylenepolyamines include polyethyleneoxidediamine, polypropyleneoxidediamine, polypropyleneoxidetriamine, diethyleneglycolpropylenediamine, triethyleneglycolpropylenediamine,

polytetramethyleneoxidediamine, polyethyleneoxide-co-polypropyleneoxidediamine, and polyethyleneoxide-co-polypropyleneoxidetriamine.

Examples of suitable commercially available polyoxyalkylenepolyamines include various JEFFAMINES from Huntsman Chemical Company such as the D, ED, and EDR series diamines (e.g., D-400, D-2000, D-5000, ED-600, ED-900, ED- 2001, and EDR-148), and the T series triamines (e.g., T-403), as well as DCA-221 from Dixie Chemical Company.

The polyamine may also comprise the condensation reaction product of diprimary amine-terminated material (i.e., the two terminal groups are primary amine) and one or more materials containing at least two groups reactive with primary amine (referred to herein at times as "difunctional primary amine-reactive material"). Such materials are preferably substantially linear so as to have the following general structure E-(L-E)u-L-E in which each E is the residue of the diprimary amine- terminated material and each L is a linking group that is the residue of the difunctional primary amine-reactive material. (By "residue" is meant those portions of the diprimary amine-terminated material and the difunctional primary amine- reactive material that remain after reaction to form the polyamine adduct.) The E and L groups are independently selected. The majority (more than 50%) of the terminal groups in the polyamine should be primary amine. Consequently, the value of u may be greater than or equal to zero, although a value of about 0 to 5 is more preferred, and a value ofO or 1 is most preferred.

The diprimary amine-terminated material may be alkyl diprimary amine, aryl diprimary amine, alkylaryl diprimary amine, a polyoxyalkylenediamine (such as those described above), or mixtures thereof. Useful alkyl diprimary amines include those having the structure NH2-R12-NH2 wherein R12 is a linear or branched alkyl group having about 1 to 12 carbon atoms such as 1,3-propane diamine, 1,6-hexanediamine, and 1,1 2-dodecanediamine. Other useful alkyl diprimary amines include triethylene tetraamine and diethylene triamine. Examples of useful aryl diprimary amines include 1,3- and 1,4-phenylene diamine as well as the various isomers of diaminonaphthalene.

An example of a useful alkylaryl diprimary amine is m-tetramethylxylene diamine.

Difunctional primary amine-reactive materials used to prepare the polyamine

contain at least two groups reactive with primary amine. The reactive groups may be different, but it is preferred that they be the same. Difunctional primary amine- reactive materials having a functionality of 2 (i. e., two groups reactive with primary amine) are preferred. Useful difunctional primary amine-reactive materials may be generally represented by the formula Y-R13-Z wherein R13 is a divalent organic radical such as an alkyl, aryl or alkylaryl group or combination thereof, and Y and Z are groups reactive with primary amine and which may be the same or may be different. Examples of useful Y and Z groups reactive with primary amine include carboxylic acid (-COOH), carboxylic acid halide (-COX, where X is a halogen, for example chlorine), ester (-COOR), aldehyde (-COH), epoxide amine alcohol (-NHCH20H), and acrylic.

Suitable carboxylic acid-functional materials are preferably those which are useful in forming polyamides, for example, cyclohexane-1,4-dicarboxylic acid and dicarboxylic acids having the structure HOOC-R14-COOH in which R14 is a linear alkyl group having about 2 to 21 carbon atoms. Aromatic dicarboxylic acids (e.g., terephthalic and isophthalic acids) may be used as can alkylaryl dicarboxylic acids, especially in combination with alkyl dicarboxylic acids. Useful carboxylic acid halide- functional materials and ester-functional materials include those which are obtained by derivatizing the above-described carboxylic acid-functional materials. Suitable aldehyde-functional materials include alkyl, aryl and alkylaryl dialdehydes such as oxaldehyde propanedialdehyde, succinaldehyde, adipaldehyde, 2-hydroxyhexanedial, phthalaldehyde, 1,4,benzenediacetaldehyde, 4,4(ethylenedioxy) dibenzaldehyde, and 2,6-naphthalene dicarbaldehyde. Most preferred are glutaraldehyde and adipaldehyde. Suitable epoxide-functional materials include aliphatic, cycloaliphatic and glycidyl ether diepoxides. Most preferred are the diepoxides based upon bis- phenol A and bis-phenol F. Useful acrylic-functional materials are preferably diacrylates and a wide variety of such materials may be successfully employed.

The organoborane amine complex is employed in an effective amount, which is an amount large enough to permit acrylic monomer polymerization to readily occur to obtain an acrylic polymer of high enough molecular weight for the desired end use but without polymerization proceeding too rapidly to allow for effective mixing and use of the resulting composition. Within these parameters, an effective amount of the organoborane amine complex is an amount that preferably provides about 0.03 to 1.5 weight % boron, more preferably about 0.08 to 0.5 weight % boron, most preferably about 0.1 to 0.3 weight % boron. The weight % of boron in a composition is based on the total weight of the composition, less fillers, non-reactive diluents, and other non-reactive materials.

As noted above, the organoborane amine complexes of the invention are especially useful for initiating the polymerization of acrylic monomers. The polymerization initiator system comprises an effective amount of the organoborane amine complex and an effective amount of a compound that is reactive with amine for liberating organoborane so as to initiate polymerization. A wide variety of materials may be used to provide the amine reactive compound. Desirable amine reactive compounds are those materials that can readily form reaction products with amines at or below (and, more preferably, at) room temperature (about 20C to 220C) so as to provide a composition that can be easily used and cured under ambient conditions.

General classes of useful amine reactive compounds include acids, anhydrides and aldehydes. Isocyanate, acid chloride, sulfonyl chloride, and the like such as isophorone diisoyanate, toluene diisocyanate and methacryloyl chloride may also be used but are less preferred because they require scrupulous drying of monomer mixtures containing these ingredients so as to preclude undesirable, premature reaction with moisture.

Acids are a preferred amine reactive compound. Any acid that can liberate the organoborane by salting the amine group may be employed. Useful acids include Lewis acids (e.g., SnC14, TiC14 and the like) and Bronsted acids such as those having the general formula R1 8-COOH, where R18 is hydrogen, an alkenyl group of 1 to 8 and preferably 1 to 4 carbon atoms, or an aryl group of 6 to 10, preferably 6 to 8 carbon atoms. The alkenyl groups may comprise a straight chain or they may be

branched. They may be saturated or unsaturated. The aryl groups may contain substituents such as alkyl, alkoxy or halogen moieties. Illustrative acids of this type include acrylic acid, methacrylic acid, acetic acid, benzoic acid, and p- methoxybenzoic acid. Other useful Bronsted acids include Hcl, H2SO4, H3PO4, phosphoric acid, phosphinic acid, silicic acid, and the like.

Also preferred as the amine reactive compound are materials having at least one anhydride group, such materials preferably having one of the following structures: R19 and R20 are organic radicals which independently may be aliphatic, including straight- and branched-chain arrangements that may be saturated or unsaturated, cycloaliphatic, or aromatic. Preferred aliphatic groups comprise 1 to 17 carbon atoms, more preferably 2 to 9 carbon atoms. Preferred aromatic groups include benzene which may be substituted with 1. to 4 carbon atom aliphatic groups.

R21 is a divalent organic radical that completes a cyclic structure with the anhydride group to form, for example, a 5 or 6-membered ring. R21 may be substituted with aliphatic, cycloaliphatic or aromatic groups, preferably aliphatic groups comprising 1 to 12, more preferably 1 to 4 carbon atoms. R21 may also contain heteroatoms such as oxygen or nitrogen provided that any heteroatom is not adjacent to the anhydride functionality. R21 may also be part of a cycloaliphatic or aromatic fused ring structure, either of which may be optionally substituted with aliphatic groups. The presence of a free-radically polymerizable group in the

anhydride-functional amine reactive compound may permit the same to polymerize with the acrylic monomers.

Aldehydes useful as the amine-reactive compound have the formula: R22-(CHO)x where R22 is an alkyl group of 1 to 10 carbon atoms, preferably 1 to 4, or an aryl group having 6 to 10 carbon atoms, preferably 6 to 8, and x is 1 to 2, preferably 1. In this formula, the alkyl groups may be straight or branch-chained, and may contain substituents such as halogen, hydroxy and alkoxy. The aryl groups may contain substituents such as halogen, hydroxy, alkoxy, alkyl and nitro. The preferred R22 group is aryl. Illustrative examples of compounds of this type include, benzaldehyde, o-, m- and p-nitrobenzaldehyde, 2,4-dichlorobenzaldehyde, p- tolylaldehyde and 3-methoxy-4-hydroxybenzaldehyde. Blocked aldehydes such as acetals may also be used.

The amine reactive compound is employed in an effective amount; that is, an amount effective to promote polymerization by liberating organoborane from the complex, but without materially adversely affecting the properties of the ultimate polymerized composition (e.g., adhesion to low energy surfaces). Within these parameters, the amine reactive compound may be provided in an amount wherein the number of amine groups in the organoborane amine complex. However, it is much more preferred that the number of equivalents of amine reactive groups be stoichiometric with the number of amine groups in the organoborane amine complex.

As noted before, the organoborane amine complex initiator systems are used to polymerize acrylic monomers. By "acrylic monomer" is meant polymerizable monomers having one or more acrylic or substituted acrylic moieties, chemical groups or functionality; that is, groups having the general structure: RO l 11 H2C=C-C-O-R' wherein R is hydrogen or an organic radical and R' is an organic radical. Where R and R' are organic radicals, they may be the same or they may be different. Blends of acrylic monomers may also be used. The polymerizable acrylic monomer may be monofunctional, polyfunctional or a combination thereof.

The most useful monomers are monofunctional acrylate and methacrylate esters and substituted derivatives thereof such as hydroxy, amide, cyano, chloro, and silane derivatives as well as blends of substituted and unsubstituted monofunctional acrylate and methacrylate esters. Particularly preferred monomers include lower molecular weight methacrylate esters such as methyl methacrylate, ethyl methacrylate, methoxy ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, and blends thereof.

Both acrylate esters and higher molecular weight methacrylate esters are less preferred for use alone, but can be especially usefully employed as modifying monomers with predominating amounts of lower molecular weight methacrylate esters so as to, for example, enhance the softness or flexibility of the ultimate composition. Examples of such acrylate esters and higher molecular weight methacrylate esters include methyl acrylate, ethyl acrylate, isobornyl methacrylate, hydroxypropyl acrylate, butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, 2- ethylhexyl methacrylate, decyl methacrylate, dodecyl methacrylate, tert-butyl methacrylate, acrylamide, N-methyl acrylamide, diacetone acrylamide, N-tert-butyl acrylamide, N-tert-octyl acrylamide, N-butoxyacrylamide, gamma- methacryloxypropyl trimethoxysilane, 2-cyanoethyl acrylate, 3-cyanopropyl acrylate, tetrahydrofurfuryl chloroacrylate, glycidyl acrylate, glycidyl methacrylate, and the like.

Another class of polymerizable monomers that are especially useful as modifiers correspond to the general formula:

R23 may be selected from the group consisting of hydrogen methyl, ethyl, and R24 may be selected from the group consisting of hydrogen, chlorine, methyl and ethyl. R25 may be selected from the group consisting of hydrogen, and The value of a is an integer greater than or equal to 1, more preferably, from 1 to about 8, and most preferably from 1 to 4. The integral value of b is greater than or equal to 1, more preferably, from 1 to about 20. The value of c is 0 or 1. Other acrylic monomers useful as modifying monomers, include ethylene glycol dimethacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, tetraethylene glycol dimethacrylate, diglycerol diacrylate, diethylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane trimethacrylate, as well as other polyether diacrylates and dimethacrylates. Also useful are dimethacrylate of bis(ethylene glycol) adipate, dimethacrylate of bis(ethylene glycol) maleate, dimethacrylate of bis(ethylene glycol) phthalate, dimethacrylate of bis(tetraethylene glycol) phthalate, dimethacrylate of bis(tetraethylene glycol) sebacate, dimethacrylates of bis(tetraethylene glycol) maleate, and the diacrylates and chloroacrylates corresponding to the dimethacrylates, and the like. Other useful acrylic monomers include the reaction product of mono- or polyisocyanates, for example, toluene diisocyanate, with an acrylate ester containing a hydroxy or an amino groups in the non-acrylate portion thereof, for example, hydroxyethyl methacrylate.

The compositions may further comprise a variety of optional additives such as thickeners, elastomeric materials (e.g., graft copolymer resins), acrylic crosslinking agents, peroxides, inhibitors such as hydroquinone, non-reactive colorants, fillers (e.g., carbon black), etc. The various optional additives are employed in an amount that does not significantly adversely affect the polymerization process or the desired

properties of compositions made therewith, The organoborane amine complex may be carried by (e.g., dissolved in or diluted by) and aziridine-functional material or a blend of two or more different aziridine-functional materials. The aziridine-functional material should not be reactive toward, coordinate or complex the amine portion of the complex and functions as an extender for the complex. The aziridine-functional material may also function as a reactive extender if the composition includes an ingredient that undergoes a ring-opening reaction with the aziridine functionality so as to permit the aziridine-functional material to react therewith or to polymerize with other constituents of the system. Advantageously, the amine reactive compound can also react with the aziridine-functional material so as to yield a 100% reactive system.

An "aziridine-functional material" refers to an organic compound having at least one aziridine ring or group, the carbon atom(s) of which may be optionally substituted by short chain alkyl groups, e.g., groups having 1 to 10 carbon atoms and preferably methyl, ethyl or propyl, so as to form, for example methyl, ethyl or propyl aziridine moieties.

Mono-functional aziridines in which a single aziridine group is a substituent in an alkyl, aryl, alkylaryl, acyl, or aroryl radical (which optionally may be substituted with other moieties that do not react with the organoborane amine complex or the aziridine functionality such as amino and hydroxyl groups) may be employed.

Particular examples of suitable mono-functional aziridines include N-ethyl aziridine, N-(2-cyanoethyl)aziridine, N-butyl aziridine, iso-butyl aziridine, 2-aziridinyl ethanol, l-aziridinyl ethanol, l-iso-butyryl aziridine, and l-butyryl aziridine.

While mono-functional aziridines are useful, polyfunctional aziridines (sometimes referred to herein as "polyaziridines"; i.e., having more than aziridine group) are more preferred as they can promote the in situ generation of a crosslinking agent. Of the various polyaziridines, those which are tri-functional are especially useful. Tris-aziridine and tris-methylaziridine of trimethylol propane triacrylate, and tris-aziridine and tris-methylaziridine of pentaerythritol triacrylate are

particularly preferred. Examples of useful, commercially available polyaziridines include CX-100 (from Zeneca Resins), XAMA-7 (from EIT, Inc.), and MAPO (tris[1-(2-methyl)aziridinyl] phosphine oxide (from Aceto Corp).

The polymerizable compositions can be easily used as two-part compositions.

The acrylic monomers are blended as would normally be done when working with such materials. The amine-reactive compound is usually included in this blend so as to separate it from the organoborane amine complex, thus providing one part of the two-part composition. The organoborane amine complex provides the second part of the composition. Advantageously, the two parts of the polymerizable composition are capable of being combined in a common, whole number mix ratio such as 10:1 or less, more preferably 1:4, 1:3, 1:2 or 1:1. The first and second parts are combined shortly before it is desired to use the composition.

The use of a low surface energy adhesive in the applications discussed herein offers many advantages. No special equipment is required to create a permanent bond where desired. No torch or heat is needed for assembly. Parts joined by the adhesive bond need not be complex so that molds and costs are reduced. Closure housings can be opened and re-closed to substantially their original integrity. Closure housings can also be expanded or reduced in size almost at will and the rejoined portions of the closure can retain substantially their original integrity. No hardware or extra kit is required for adding extensions to original closures. Tooling costs are reduced. The methods illustrated herein can be used for both variable and fixed closure shapes. For example, closure diameters can be increased and closure lengths can be adjusted. As a result of the expansion possibilities, more room can be provided in closures for splice trays for fiber optics, more buffer tube storage and more space for general electronics.

Although illustrative embodiments of the invention have been shown and described, a wide range of modification, change and substitution is contemplated in the foregoing disclosure and in some instances, some features of the present invention may be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.