GB1564976A

GB1564976A - Marine dock installations

Info

Publication number: GB1564976A
Application number: GB726/77A
Authority: GB
Original assignee: Goodyear Tire and Rubber Co
Current assignee: Goodyear Tire and Rubber Co
Priority date: 1976-01-26
Filing date: 1977-01-10
Publication date: 1980-04-16
Also published as: NO770245L; FR2339022B1; JPS5291296A; FR2339022A1; IT1077828B; NL7700449A; BE850541A; DE2702232A1; ZA767656B; AU2091776A; AU505024B2

Description

(54) MARINE DOCK INSTALLATIONS (71) We, THE GOODYEAR TIRE & BR< RUBBER COMPANY, a corporation organised under the laws of the State of Ohio, United States of America, with offices at 1144 East Market Street, Akron, Ohio, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to marine dock installations incorporating microporous polyurethane dock fenders, and especially those for ship to shore, or ship to off-shore docking protection. It relates more particularly to very large protective devices for such applications having a specific gravity of from 0.4 to less than 1.1.

Although elastomeric dock fenders have been made and used for many years to protest ships, dolphins, truck loading platforms, offshore drilling rigs or barges and related marine structures, their construction and manufacture have presented considerable difficulty which becomes greatly exaggerated as the protective requirements dictate sizes and shapes of giant proportions. Thus, these huge dock fenders have become extremely heavy, costly and difficult to make. They consume high amounts of heat and mechanical energy in their manufacturing process. Actually, the specific gravity of said products were considerably greater than 1.2. To reduce weight, socalled air bags or inflated type fenders have been developed and used in some applications but have undesirable qualities, especially high cost and malfunction when punctured.

An object of this invention is to provide large marine dock installations incorporating fends having a specific gravity of from 0.4 to less than 1.1, and preferably less than one, but having the ability to withstand the shock associated with this service.

According to the present invention, a marine dock installation incorporates a molded microporous polyurethane dock fender of unitary construction comprising a body consisting essentially of a microporous polyurethane having a specific gravity of from 0.4 to less than 1.1, the said body being molded so as to fit in a retaining relationship on a base member of predetermined configuration and having an untrimmed outermost surface (as herein defined).

Additional advantages and other objects of this invention can be seen by reference to the accompanying drawing, and, for example, veiwing a fender of a marine dock installation as one having dimensions of six feet by three feet or larger.

Referring specifically to Figure 1, a perspective view of a wing type trapezoidal open base dock fender is shown; Figure 2 shows a perspective view of a doughnut shaped dock fender positioned on a pillar of an offshore drilling vessel, dolphin or like assembly; and Figure 3 shows another fender of an installation according to the invention, similar to the dock fender of Figure 2 except that the length is usually greater than the diameter to give a tube-like appearance.

A great variety of other shapes and sizes are also used used or desirable and would be within the scope of this invention. Also the present dock fender may be modified in that metal, plastic, fabric, or other inserts may be embedded in the said body as added reinforcement.

The advantages and objects of this invention can be obtained by injecting or pouring a liquid microporous polyurethane forming reaction mixture into a mold having a cavity of the dimensions of the dock fender desired, said microporous polyurethane forming reaction mixture being caused to react and fill the cavity with a microporous polyurethane having a specific gravity of from 0.4 to less than 1.1, e.g. 0.7 to less than 1:1; the preferred specific gravity, however, is 0.6 to 0.95.

It has been learned that the microcellular polyurethane dock fender of this density range can with stand shock loads sufficient to compress the fender 50 percent or more many times without signs of failure, and can effectively absorb the shock force to prevent damage to the structure or craft concerned.

Another advantage of this invention relates to the molds and equipment required for making the present dock fenders as compared to those required for making dock fenders from ethylene propylene diene monomer (EPDM) rubber. Molds can be of much lighter con struction providing considerable savings both in cost and time required to make molds.

When regular rubber compounds are used such as natural, Neoprene, EPDM, butadiene styrene rubbers, large amounts of heat and pressure are required to soften and move the rubber into the extrusion die or mold to shape and subsequently cure or vulcanize it. However, this invention utilizes liquid microporous polyurethane forming materials which are easily mixed and poured or injected in the liquid state into the desired mold and allowed to polymerize or cure primarily through the exothermic reaction. Thus, expensive capital equipment such as banburies, rollmills, extruders, hot platen presses and pot heaters are not needed. It will be appreciated that a very precious commodity, energy, is used very sparingly in the process used in making the dock fenders of this invention.

The nature of this invention can be more readily appreciated by reference to the following illustrative and exemplifying examples wherein all parts and percentages are by weight unless otherwise indicated.

EXAMPLES A fibreglass - epoxide mold about six feet by two feet having a cavity of the shape shown in Figure 1 was filled by injecting into the cavity a charge of a liquid microporous polyethane forming reaction mixture and allowing it to foam and cure to give a wing type trapezoidal open base dock fender. This fender was removed from the mold and then the physical properties of this microporous poly urethane dock fender were compared with a commercial ethylene propylene dience monomer dock fender. In some embodiments the dock fender can be modified in that a metal plate reinforcing member can be placed in the mold and into each of the wings of the dock fender.

The microporous polyurethane forming reaction mixture used to pour the above dock fender was made by mixing 86.66 parts of polypropylene ether triol of 6000 molecular weight, 8.25 parts ethylene glycol, 5.09 parts diethanol dicarbamate, 0.007 parts of dibutyltin dilaurate, 0.10 parts of triethylene diamine, 2.00 parts of CCI,F, i.e. trichlorofluoromethane (blowing agent), and 3.00 parts of an orange colored pigment and this mixture was then mixed with 76.59 parts of an adduct of 4,4' - diphenyl methane diisocyanate with a low molecular weight glycol or diglycol having a free NCO content of 1S22 percent on a suitable polyurethane machine mixer capable of filling a mold by injection.

The polyurethane dock fender was 15 to 20 percent lighter in weight than the ethylene propylene diene monomer rubber (EPDM) dock fender at the same Shore D hardness. It could be shaped to closer tolerances and have equal or better compression loading and flex properties. A further advantage of the polyurethane dock fender was the ease with which metal reinforcing members could be incorporated therein. Also, the mounting holes are cast in place, to eliminate the drilling associated with EPDM dock fenders.

A polyurethane dock fender of about 0.7 specific gravity, and 24 inches in outside diameter, 12 inches in inside diameter, and 48 inches in length, of shape shown in Figure 3, was flexed fifty times to bore closure in a Verson press with no indication of cracking or distortion, and still retained its shock absorbing capability.

A mol of polyester polyol, or a polyether polyol of two to three hydroxyls of 1000 to 7000 molecular weight was reacted with 1.15 mols of an organic polyisocyanate by prepolymer or one-shot method with sufficient croslinker, preferably of the glycol type to react with one to 20 percent of the excess polyiso cyanate relative to the polyester or polyether polyol to give a liquid reaction mixture suitable for making dock fenders.

The polyurethanes prepared from polypropylene ether diol or triol and methane di phenyl.diisocyanate or its hydrogenated derivative, when prepared for making dock fenders for use in a marine atmosphere, have suitable hydrolytic stability properties to withstand exposure to a marine atmosphere.

To compare a microporous polyurethane dock fender with a commercial EPDM one, a microporous polyurethane dock fender was prepared using the following recipe: Ingredient Weight, parts Polypropylene ether triol of 4800 mol. wt. 86.6 Ethylene glycol 8.27 Carbamate of diethanol 5.07 Carbon black 2.00 Triethylene diamine 0.01 Dimethyltin dithioglycolate 0.005 Dichlorodifluoro methane (CCl2FG) (blowing agent) 1.0 Mondur PF 77.01 Index 1.05 The above ingredients were mixed in the order listed and then Mondur PF, a quasi prepolymer of methane diphenyl diisocyanate and a diglycol such as dipropylene glycol, was added and mixed well before pouring into the dock fender mold and cured at room temperature.

Test specimens made at the time the dock fenders were made were tested and compared with specimens of a commercial EPDM dock fender. The results are shown in Table I. Polyurethane Number 1 differs from polyurethane Number 2 in that No. 2 contains 1.0 part of an alkylated phenol as an antioxidant. These test data indicate these microporous polyurethanes to be as stable as or more so than EPDM in a marine atmosphere.

TABLE I Polyurethane Physical Properties No. 1 No. 2 EPDM Tensile--original (psi) 2100 1660 2430 ,' change after 42 days in Salt water 1580F. -12 +28 -7 ELlongationHriginal (%) 250 175 510 4 change after 42 days in Salt water 1580F. + 12 +48 -13 Tensile /O change after 90 days Salt Water 258oF. -4 +46 -23 Elongation-0/0 change after 901 days Salt Water 1580F. +6 +46 -23 Specific Gravity 0.89 0.85 1.15 The preferred microporous polyurethane forming reaction mixtures for making the present microporous polyurethane dock fenders are mixtures of polyether polyols comprising polypropylene ether diol or triol and polytetramethylene ether glycol of 3000 to 6000 molecular weight, an organic polyisocyanate such as methane diphenyl diisocyanate, sometimes called MDI, and hydrogenated MDI, a curative comprising a glycol or polyglycol of less than 1000 and preferably less than 500 molecular weight and sufficient blowing agent (e.g. the above-mentioned CCl3F or CCl2F2) to give the desired specific gravity of the microporous polyurethane.

While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the scope of the invention.

Where we specify, in the present descrip tion and claims, that the dock fender comprises a molded microporous polyurethane body having an untrimmed outermost surface, we mean that the outermost surface as formed on a microporous polyurethane body in the course of its molding remainst undisturbed when the body is a dock fender of an installation according to this invention, and is not, for instance, penetrated by drilling to provide mounting holes as in the above-mentioned EPDM dock fenders.

WHAT WE CLAIM IS:- 1. A marine dock installation incorporating a molded microporous polyurethane dock fender of unitary construction comprising a body consisting essentially of a microporous polyurethane having a specific gravity of from 0.4 to less than 1.1, the said body being molded so as to fit in a retaining relationship on a base member of predetermined configuration and having an untrimmed outermost surface (as herein defined).

2. The installation of Claim 1 wherein the microporous polyurethane has a specific gravity of 0.7 to less than 1.1 and is a reaction product of a polypropylene triol of about 4800 molecular weight and a curative comprising ethylene glycol and the carbonate of diethanol with a quasi prepolymer of methane diphenyl diisocyanate and dipropylene glycol.

3. The installation of Claim 1 wherein the said body has wings joined by an open trapezoidal member.

4. The installation of Claim 1 wherein the said body has a toroidal shape.

5. The installation of Claim 1 wherein the said body has a cylindrical shape.

6. The installation of Claim 1 modified in that methal, plastic, fabric, or other inserts are embedded in the said body as added reinforcement.

7. The installation of Claim 1 having holes molded in the said body to facilitate attachment of the fender to a support.

8. The installation of Claim 1 wherein the said specific gravity is 0.6 to 0.95.

9. The installation of claim 1, the said microporous polyurethane body having been

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. fender. The results are shown in Table I. Polyurethane Number 1 differs from polyurethane Number 2 in that No. 2 contains 1.0 part of an alkylated phenol as an antioxidant. These test data indicate these microporous polyurethanes to be as stable as or more so than EPDM in a marine atmosphere. TABLE I Polyurethane Physical Properties No. 1 No. 2 EPDM Tensile--original (psi) 2100 1660 2430 ,' change after 42 days in Salt water 1580F. -12 +28 -7 ELlongationHriginal (%) 250 175 510 4 change after 42 days in Salt water 1580F. + 12 +48 -13 Tensile /O change after 90 days Salt Water 258oF. -4 +46 -23 Elongation-0/0 change after 901 days Salt Water 1580F. +6 +46 -23 Specific Gravity 0.89 0.85 1.15 The preferred microporous polyurethane forming reaction mixtures for making the present microporous polyurethane dock fenders are mixtures of polyether polyols comprising polypropylene ether diol or triol and polytetramethylene ether glycol of 3000 to 6000 molecular weight, an organic polyisocyanate such as methane diphenyl diisocyanate, sometimes called MDI, and hydrogenated MDI, a curative comprising a glycol or polyglycol of less than 1000 and preferably less than 500 molecular weight and sufficient blowing agent (e.g. the above-mentioned CCl3F or CCl2F2) to give the desired specific gravity of the microporous polyurethane. While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the scope of the invention. Where we specify, in the present descrip tion and claims, that the dock fender comprises a molded microporous polyurethane body having an untrimmed outermost surface, we mean that the outermost surface as formed on a microporous polyurethane body in the course of its molding remainst undisturbed when the body is a dock fender of an installation according to this invention, and is not, for instance, penetrated by drilling to provide mounting holes as in the above-mentioned EPDM dock fenders. WHAT WE CLAIM IS:-

1. A marine dock installation incorporating a molded microporous polyurethane dock fender of unitary construction comprising a body consisting essentially of a microporous polyurethane having a specific gravity of from 0.4 to less than 1.1, the said body being molded so as to fit in a retaining relationship on a base member of predetermined configuration and having an untrimmed outermost surface (as herein defined).

4. The installation of Claim 1 wherein the said body has a toroidal shape.

5. The installation of Claim 1 wherein the said body has a cylindrical shape.

prepared from a polyurethane forming formulation substantially corresponding to any of those set forth in the foregoing Examples section.