US3538700A - Glass rovings impregnated with thermoplastic polyurethane resins - Google Patents

Description

United States Patent 3,538,700 GLASS ROVINGS IMPREGNATED WITH THERMO- PLASTIC POLYURETHANE RESINS Peter H. Hofer, Berkeley Heights, N.J., assignor to Union Carbide Corporation, a corporation of New York No Drawing. Continuation-impart of applications Ser. No. 502,364, Oct. 22, 1965, and Ser. No. 693,460, Dec. 26, 1967. This application July 16, 1968, Ser. No. 745,131

Int. Cl. D02g 3/18; C03c 25/02 U.S. Cl. 57-139 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to glass rovings, impregnated with thermoplastic polyurethane resins, which are char acterized by a low weight-high tensile strength ratio, by relatively low elongation, by excellent flexibility characteristics and by excellent abrasion resistance and are excellently suited for use in nonwoven, nonbraided rope, in aerial antenna systems and also a buoyant submarine cables such as submarine antenna systems capable of transmitting and receiving radio signals while the submarine is submerged at greater than periscope depth.

This application is a continuation-in-part application of my copending application Ser. No. 502,364, filed Oct. 22, 1965, and also of my copending application Ser. No. 693,460, filed Dec. 26, 1967.

This invention relates to glass rovings which are impregnated with thermoplastic polyurethane resins. More particularly, this invention relates to glass rovings, im-

' pregnated with thermoplastic polyurethane resins, which are characterized by a low weight-high tensile strength ratio, by relatively low elongation, by relatively high flexibility characteristics and by relatively high abrasion resistance (filament to filament abrasion) and are excellently suited for use in nonwoven, nonbraided rope, in aerial antenna systems and also in submarine antenna systems which are capable of transmitting and receiving radio signals while the submarine is submerged at greater than periscope depth.

One type of submarine antenna system which has been commonly used to transmit and to receive radio signals, while the submarine is submerged at greater than periscope depth, is made up of an electrical conductor, such as a copper conductor and as successive layers surrounding this electric conductor (1) insulation, as for example, thermoplastic insulation such as polyethylene (2) metal braid, such as copper braid which serves as the second conductor (3) a second layer of thermoplastic insulation (4) metal filaments, such as steel filaments, which serve to provide strength for the system and (5) a foamed jacket such as polyethylene foam which serves to provide buoyancy to the system.

Although this type of antenna system has been used for receiving and for transmitting radio signals from submerged submarines, its performance has been relatively poor. The poor performance of such a system is due, primarily, to the fact that it is not sufiiciently bouyant to float on top of the water, which is necessary in order that it properly transmit and receive.

In an attempt to improve the buoyancy of such systems, it has been proposed to reduce the weight thereof by eliminating metalfilaments therefrom. This expediency has not proved to be particularly successful. It has been found that in order to increase the buoyancy of such systems to a significant degree, it is necessary to drastically reduce the number of metal filaments therein. This results in an antenna system which is too weak, structurally, to have any great value. That is to say, such antenna systems do not have sufiicient tensile strength to Withstand,

without breaking, forces, due to drag to which the antenna system is subjected when it is in use and the submarine is moving at relatively high speeds.

The present invention provides glass rovings impregnated with thermoplastic polyurethane resins which are characterized by a low weight-high tensile strength ratio, the tensile strengths being as high as 500,000 p.s.i., by relatively low elongation, generally on the order of less than about 3 percent, by excellent flexibility characteristics and by excellent abrasion resistance. Buoyant cable systems, such as buoyant antenna systems, in Which the impregnated glass rovings of this invention are used, have 8 times the tensile strength of a system which has the same buoyancy characteristics but has steel filaments in lieu of the impregnated glass rovings.

The impregnated glass rovings of this invention contain from about 8 to about 40 percent by weight and preferably about 18 to about 22 percent by weight thermoplastic polyurethane resin based on the combined weight of the glass and polyurethane resin.

The glass rovings themselves are made up of a plurality of individual glass filaments generally ranging in number from about 50 to about 20,000, with the'filaments ranging, generally, in diameter of from about 5 microns to about 25 microns. For purposes of this invention the glass roving described below is particularly preferred:

Diameter of glass filaments=about 8 to about 10 microns Number of filaments per end=about 200-210 Number of ends per roving=about 6 to about 40 The thermoplastic polyurethane resins which are used to impregnate the glass rovings are well known materials and are generally prepared by reacting a diisocyanate with a dihydric compound to produce a polymer having more than one group per molecule. As a general rule, the diisocyanate and dihydric compound are admixed in about equivalent amounts and reacted to a thermoplastic product.

Both aliphatic and aromatic diisocyanates can be used as reactants with dihydric compounds to produce thermoplastic polyurethane resins. Illustrative of such diisocyanates are the following: tetramethylene-l,4-diisocyanate, hexamethylene-1,6-diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate 1-chlorophenylene-2, 4-diisocyanate, naphthalene 1,5 diisocyanate, tolylene- 2,4 diisocyanate, diphenylmethane-4,4-diisocyanate, diphenyl 4,4-diisocyanate, cyclohexylene-l,4-diisocyanate, cyclohexylene-l,2-diisocyanate and the like.

Of the dihydric compounds which are used to react with the diisocyanates, the polyalkylene glycols are preferred.

Suitable polyalkylene glycols can be represented by the formula:

HOtROi H wherein R is an alkylene radical such as methylene, propylene and the like and n is an integer greater than 2. Also suitable are the commercially available glycols marketed under the name Carbowax. Particularly preferred are the poly(ethylene glycols) and the poly(propylene glycols) having an average molecular weight of about 300 to 750. Other suitable dihydric compounds are the hydroxyl terminated polyesters as for example a hydroxyl terminated polyester of adipic acid and l,4-butanediol.

The impregnation of the glass rovings with the thermoplastic polyurethane resins can be carried out by forming a solution of thepolyurethane resin in a suitable solvent such as dimethyl formamide, tetrahydrofuran, a ketone etc. and then submerging a fully Wound spool of glass roving in the solution, subjecting the solution and the submerged spool to a reduced pressure of about 0.5 mm. to about 15 mm. of Hg and maintaining this pressure until cessation of bubbling and then increasing the pressure to about 1,000 to about 6,000 lbs. per square inch for about two to about ten minutes and thereafter allowing the system to return to atmospheric pressure.

Alternatively, the glass roving can be impregnated by passing the roving through a solution of the thermoplastic polyurethane resin and then passing the coated roving through a rolling bank of the polyurethane solution as described in my copending application Ser. No. 693,460, filed Dec. 26, 1967.

In formulating the coating solutions, it is customary to provide the solutions with a solids content of about 15 percent by weight to about 40 percent by weight.

If desired, colorants, stabilizers, ultra-violet light absorbers and the like can be added to the polyurethane resins, in amounts well known in the art, prior to impregnation of the glass rovings.

The glass rovings of Examples 1-2, were impregnated by the procedure described in Example 1 of my copending application Ser. No. 502,364, filed Oct. 22, 1965.

The glass rovings of Examples 3-5 were impregnated by the procedure described in Example 1 of my copending application Ser. No. 693,460, filed Dec. 2 6, 1967.

Tests noted in the examples of this application were carried out according to procedures described in Appendix A page 88 and seq. of a report entitled U.S. Navy Underwater Sound Laboratory Contract N-140-66C- 0403," dated Feb. 15, 1968, with the breaking strength, in pounds, being the load break, of the tensile strength test.

EXAMPLE 1 Impregnated glass roving:

88 percent by weight glass (glass roving had 20 ends and 204 filaments per end with each filament being about 12 microns in diameter).

12 percent by weight of a thermoplastic polyurethane resin (reaction product of polybutylene adipatemethylene phenylene diisocyanate and butanediol).

Coating solution:

15 percent by weight thermoplastic polyurethane resin. Solventdimethyl formamide. Properties of the impregnated glass roving:

Breaking strength=94 lbs. Tensile strength (glass area)=195,000 p.s.i. Elongation=2.6 percent.

EXAMPLE 2 Impregnated glass roving:

'88 percent by weight glass (described in Example 1). 12 percent by weight of a thermoplastic polyurethane resin (reaction product of tolylene-1,4-diisocyanate and ethylene glycol).

Coating solution:

40 percent by weight thermoplastic polyurethane resin. Solvent-methylethyl ketone.

Properties of the impregnated glass roving:

Breaking strength=166 lbs. Tensile strength (glass area) =206,000 p.s.i. Elongation=2.6 percent.

EXAMPLE 3 Impregnated glass roving:

91.8 percent by weight glass (described in Example 1). 8.2 percent by weight thermoplastic polyurethane resin (reaction product of diphenylmethane-1,4-diisocyanate and a hydroxyl terminated polyester of 4 1,4-butanediol and adipic acid containing about 40 percent by weight combined diisocyanate).

Coating solution:

15 percent by weight thermoplastic polyurethane resin. Solvent5050 mixture by weight of acetone and tetrahydrofuran.

Properties of the impregnated glass roving:

Breaking strength=93 lbs. Tensile strength (glass area)=190,000 p.s.i. Elongation=2.4 percent.

Impregnated glass roving:

84.8 percent by weight glass (described in Example 1). 15.2 percent by weight thermoplastic polyurethane resin (described in Example 3).

Coating solution:

25 percent by weight thermoplastic polyurethane resin. Solvent-tetrahydrofuran.

Properties of the impregnated glass roving:

Breaking strength= lbs. Tensile strength (glass area)=2l0,000 p.s.i. Elongation=2.5 percent. Abrasion resistance=526 strokes.

EXAMPLE 5 This impregnated glass roving was aged for 16 months under ambient conditions. At the end of this period of time, there was no significant change in tensile strength. Also, the impregnated glass roving was immersed in water for seven days. At the end of this time, there was no significant change in tensile strength.

In order to further demonstrate the unique properties of the glass rovings of this invention, Example 5 was repeated using the polyurethane resin of Example 5 as well as other thermoplastics. The polymer content and properties of the impregnated rovings are noted below:

Tensile strength Abrasion Percent by weight in p.s.i. resistance thermoplastic glass area in strokes Example 6.... 13.6 polyurethane- 439, 000 66 Example 7-.-. 16. 1 p0lyuretl1ane.. 432, 000 83 Example 8-.-. 18. 6 polyurethane.. Example 9.--- 24. 0 polyurethane Example 10... 29. 2 polyurethane Control 1.. 14.0 copolymer of ethylenevmyl acetate containing about 14 ercent by weight combine vinylacetate.

The impregnated glass rovings of Examples 1-10 were formed into nonwoven, nonbraided rope by methods well known in the art, as for example, are described in US. Pat. No. 3,371,476 and also by helically winding impregnated glass rovings together. Cables were also formed from the impregnated glass rovings of this invention, by methods Well known in the art.

It is to be understood that the disclosure of my copending applications, previously identified in this application are incorporated herein by reference.

What is claimed is: r

1. A glass roving impregnated with a thermoplastic nonfoamed polyurethane resin formed by the reaction of approximately equivalent amounts of a diisocyanate and dihydric compound wherein the polyurethane resin content is about 8 to about 40 percent by weight based on the combined weight of glass and polyurethane resin.

2. A glass roving as defined in claim 1 wherein the polyurethane resin content is about 18 to about 22 percent by weight based on the combined weight of glass and polyurethane resin.

3. A glass roving as defined in claim 1 wherein each glass roving is made up of glass filaments of about 50 to about 20,000 in number with the diameter of each filament being about 5 microns to about 25 microns.

4. A glass roving as defined in claim 3 wherein the glass filaments have a diameter of about 8 to about 10 microns, the number of filaments per end is about 200 to about 210 and the number of ends per roving is about 6 to about 40.

5. A glass roving as defined in claim 1 wherein the polyurethane resin is the reaction product of diphenylmethane 1,4-dissocyanate and a hydroxyl terminated polyester of 1,4-butanediol and adipic acid.

6. A glass roving as defined in claim 1 wherein the polyurethane resin is the reaction product of tolylene-l,4- diisocyanate and ethylene glycol.

7. A glass roving as defined in claim 1 wherein the thermoplastic polyurethane resin is the reaction product of polybutylene adipate, methylene phenylene diisocyanate and butanediol.

8. A nonwoven, nonbraided rope comprising glass rovings impregnated with a polyurethane resin as defined in claim 1.

References Cited UNITED STATES PATENTS 2,862,281 12/1958 Klauser 117-161 X 2,993,813 7/1961 Tischbein 117161 X 3,091,019 5/1963 Wetterau 161'93 X 3,245,827 4/1966 Weber 117-126 X 3,271,825 9/1966 Dennis 2875 X 3,323,975 6/1967 Marzocchi et al. 117126 X 3,371,476 3/1968 Costello et a1 2875 X WILLIAM D. MARTIN, Primary Examiner D. COHEN, Assistant Examiner US. Cl. X.R.