METHOD AND OBJECTS FORMED FROM POLYUREA POLYMERS

Abstract

Methods for forming large molded objects from polyurea coatings that are exceptionally durable, rigid and strong enough to remain intact under all conditions involving structural integrity, even without structural reinforcements. Such methods comprise providing a mold or substrate surface onto which the molded object will be formed. A first gelcoat layer is formed upon the mold, upon which is formed a second epoxy/polyurea coating, followed by a third polyurea coating mixed with chopped fiberglass, and a final fourth epoxy/polyurea coating. The combined coatings are allowed to cure and then removed from the mold. Such methods are exceptionally effective in the manufacture of pools and spas.

Claims

1. A method for the manufacture of a molded object comprising the steps: a) providing a mold defining an outer surface upon which said molded object will be formed; b) spraying a polyaspartic coating upon said outer surface of said mold provided in step a) such that a first coating is formed; c) spraying an epoxy/polyurea coating over said first coating formed in step b) such that a second coating is formed; d) spraying a mixture of a reinforcing polyurea polymer with chopped fiberglass upon said second coating formed in step c) such that a third coating is formed; e) spraying an epoxy/polyurea over said third coating formed in step d) such that a fourth coating is formed; f) allowing said coating in step e) to cure such that said first, second, third and fourth coatings cooperate to form said molded object upon said mold; and g) removing said molded object formed in step f) from said mold.

2. The method of claim 1 wherein in step b), said coating is formed to have a thickness ranging from 20 to 25 mils.

3. The method of claim 1 wherein in step d), said coating is formed to have a thickness of ranging from 250 to 300 mils.

4. The method of claim 1 wherein in steps c) and e), said coatings is formed to have a thickness ranging from 60 to 80 mils.

5. The method of claim 1 wherein a cure time ranging from 45 seconds to 3 hours is allowed to lapse from when step b) is performed to when step c) is performed.

6. The method of claim 1 wherein said molded object comprises a swimming pool.

7. The method of claim 1 wherein said molded object comprises a spa.

8. The method of claim 1 wherein in step d) said chopped fiberglass is added in an amount ranging from 40% to 60% by weight of said performance modified polyurea.

9. The method of claim 13 wherein said chopped fiberglass is added in an amount of approximately 20% by weight of said reinforcing polyurea polymer.

10. The pool produced by the method of claim 6.

11. The spa produced by the method of claim 7.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:

[0018] FIG. 1 is a schematic block diagram for performing a method for the rapid manufacture of molded objects from polyurea-based coatings according to a preferred embodiment of the present invention;

[0019] FIG. 2 is a perspective view of a first polyurea coating being sprayed upon a mold by an individual;

[0020] FIG. 3 is a perspective view of a second polyurea coating being sprayed upon the first coating as shown in FIG. 2;

[0021] FIG. 4 is a perspective view of a third polyurea coating being sprayed upon the second coating as shown in FIG. 3;

[0022] FIG. 5 is a perspective view of a fourth polyurea coating being sprayed upon the third coating as shown in FIG. 4;

[0023] FIG. 6 is an exploded view of the combined solidified coatings applied as shown in FIGS. 2-4 shown being removed from the mold; and

[0024] FIG. 7 is a perspective view of a spa as formed by the multiple coatings and removed from the mold in FIG. 5.

DETAILED DESCRIPTION

[0025] The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the functions and the sequence of steps for developing and operating the invention in connection with the illustrated embodiment. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.

[0026] Referring now to the drawings, and initially to FIG. 1, there is shown a schematic diagram for sequentially preforming a method 10 for the rapid manufacture of molded objects from polyurea-based coatings according to a preferred embodiment of the present invention. Such method 10 involves forming the molded object via four sequentially applied coatings of polymers, discussed more fully below, upon a mold or substrate per conventional molding processes. To that end, the method contemplates a mold or substrate will be provided in initial step 12 that will serve as the basis for forming the molded structure. Such mold or substrate may take any of a variety of forms known in the art that are operative to define an exterior shape that will serve to receive the coatings applied thereto that, when cured, will define the shape of the molded object. Exemplary of such molds include fiberglass molds having a tooling-gel exterior surface covered with a standard wax mold release agent as are utilized in the production of fiberglass pools and spas, such as spa mold 202 as shown in FIGS. 2-6.

[0027] To such mold provided for in step 12, there is applied via step 14 a first coating that will preferably serve as a gelcoat. The first polyurea coating will preferably comprise a polyaspartic polyurea coating that may take the form of a two-component polyurea elastomer spray. Among the types of polyurea coating exceptionally well-suit for such applications is GelFlex polyaspartic coating manufactured by VersaFlex Inc. of Kansas City, Kans. that provides for a first component or A Side with the following formulation:

TABLE-US-00001 Weight CAS Concentration Chemical Name number % Hexamethylene Diisocyanate 28182-81-2 90-100% Homopolymer
The second component or B Side with the following formulation:

TABLE-US-00002 Weight CAS Concentration Chemical Name number % Aspartic Acid Ester 1 68253-59-6 40-50%  Cycloaliphatic Amine 20-30%  Titanium Dioxide 13463-67-7 0-20% Amine-based Polyol 5-10% Trade Secret 5-10% Fumaric Acid Diester 623-91-6  1-5% Adhesion Promoter 0.1-1%  Amorphous Hydrophobic Fumed Silica 67762-90-7 0-0.1% 

[0028] Per the manufacturer's instructions, Sides A and B are mixed in a 1:1 ratio by volume with Side B being pre-mixed. The polyurea coating can also be pigmented as desired for a given application, such as to give a pool/spa a desired color.

[0029] Such first coating is applied in step 14 via spraying technique 200 as illustrated in FIG. 2. Preferably the polymer coating 204 is evenly applied about the mold to a thickness ranging from 20 to 25 mils. To that end, it is contemplated that coating 204 can be applied to the mold 202 via conventional spraying 206 using conventional spraying equipment 208 as applied by an individual 210 making passes about the mold 202 to ensure even application. Advantageously, due to the chemical properties of the first gelcoat, the coating 204 need only set for 45 seconds to a minute and thus allows for rapid manufacturing.

[0030] Within three hours or less after application of the first coating 204, a second polyurea coating 302 is applied over the first coating 204 per step 16 in FIG. 1 and shown as 300 in FIG. 3. Such coating 302 will preferably comprise a novolac epoxy/polyurea hybrid coating formulated to impart increased stiffness and provide an additional waterproof barrier. An exemplary coating material includes AquataFlex® 506 produced by Raven Lining Systems of Kansas City, Kans., in conjunction with VersaFlex, Inc. Such coating is surface tolerant and is hydrophobic to provide excellent waterproofing properties and adhesion. Like the first gelcoat coating, the second coating will comprise a two-part spray. The first component or A Side includes the following formulation:

TABLE-US-00003 Weight CAS Concentration Chemical Name number % Polyurethane Prepolymer 30-60% Diphenylmethane Diisocyanate (MDI) 26447-40-5 10-30% Mixed Isomers 4,4′-Diphenylmethane Diisocyanate (MDI) 101-68-8 10-30%
The second component or B Side includes the following formulation:

TABLE-US-00004 Weight CAS Concentration Chemical Name number % Diethyltoluenediamine 68479-98-1 5-10%  Trade Secret 1-5% Titanium Dioxide 13463-67-7 0-5% Polyether Polyol 25791-96-2 1-5% Cashew, nutshell liquid 8007-24-7 1-5% Trade Secret 1-2% Carbon Black 1333-86-4 0-1%

[0031] Per the manufacturer's instructions, Sides A and B are mixed in a 1:1 ratio by volume with Side B being pre-mixed. Sides A and B are likewise preferably warmed to a minimum of 70° F. prior to processing. Such coating may be applied via conventional spraying techniques 304 utilizing conventional spraying equipment 306 known in the art and will be applied to a thickness ranging from approximately 60 to 80 mils. Advantageously, the second coating 302, due to its formulation, sets very rapidly and once applied to the correct thickness range can immediately accommodate the application of the third coating at step 18 of FIG. 1.

[0032] Step 18, also shown as application 400 of a third reinforcing coating 402 in FIG. 4, preferably comprises spraying a performance modified, reinforcing polyurea coating/lining material formulated for industrial applications that receive constant or intermittent attack from contained materials, subsurface hydrostatic pressure, corrosive substances and abrasive action. Among the types of such suitable polyurea reinforcing coating materials 402 well suited for practicing the present invention include commercially available 100% solids, semi-structural, two-component performance modified polyurea spray coating/lining. An exemplary reinforcing polyurea coating as applied in step 18 includes VersaFlex Inc.'s AroStruct brand of structural polyurea spray coating/lining material. Per the other aforementioned coatings, the AroStruct coating is a two-component formulation wherein the first component or Side A comprises:

TABLE-US-00005 Weight CAS Concentration Chemical Name number % Polymeric Diphenylmethane Diisocyanate 9016-87-9 50-60%  (pMDI) 4,4′-Diphenylmethane Diisocyanate 101-68-8 30-40%  (MDI) Isocyanic acid, polymethylenepoly- 58228-05-0 1-5% phenylene ester, polymer with methyloxirane polymer with oxirane ether with 1,2,3-propanetriol (3:1) Oxirane, methyl-, polymer with oxirane, 112898-48-3 1-5% ether with 1,2,3-propanetriol (3:1), polymer with 1,1′- methylenebis[isocyanatobenzene] 2,4′-Diphenylmethane Diisocyanate 5873-54-1 1-5% (MDI)
The second or Side B component of the preferred AroStruct coating is formulated as follows:

TABLE-US-00006 Weight CAS Concentration Chemical Name number % Trade Secret 30-40%  Amine-based Polyol 20-30%  Polyoxyalkyleneamine 9046-10-0 20-30%  Glycerine, propoxylated aminated 64852-22-8 5-10%  Diethyltoluenediamine 68479-98-1 5-10%  Titanium Dioxide 13463-67-7 0-5% Trimethylolpropane 77-99-6 1-5% Polyether Polyol 25791-96-2 0-5% Carbon Black 1333-86-4 0-1%

[0033] Per the manufacturer's instructions, Sides A and B are mixed in a 1:1 ratio by volume with Side B being pre-mixed. Sides A and B are likewise preferably warmed to a minimum of 70° F. prior to processing.

[0034] To provide greater strength and structural reinforcement to the finished molded product, chopped fiberglass will be added to and mixed with the third coating so that the coating will be applied as a uniform mixture of polyurea coating and fiberglass over the second coating 302. Ideally, the chopped fiberglass will be added in an amount ranging from 40% to 60% by weight of the coating material.

[0035] As shown in FIG. 4, the application 400 of the third coating 402 can be applied via conventional spraying techniques 404 by the individual 210, including those techniques well-know for spraying fiberglass/polymer mixtures, and will preferably be applied via multiple spraying passes such that a uniform layer from 250 to 300 mils is ultimately formed over the second coating 302.

[0036] Once the third coating 402 is applied, a final fourth coating is then formed over thereover in step 20 of FIG. 1 and shown as application 500 in FIG. 5. The fourth coating 502 will preferably comprise the same novolac epoxy/polyurea hybrid coating utilized in step 16 and applied in the same manner and thickness of 60 to 80 mils.

[0037] Following the application of the fourth or final coating 20 that is ultimately applied per FIG. 1, the mixture of coatings is then allowed to cure per step 22 of FIG. 1 upon the mold 202 or substrate for approximately one hour, after which the coatings 204, 302, 402, 502 will have cooperated to form the finished molded structure, illustrated as 602 in FIGS. 6 and 7. Per convention molding processes, the molded structure 602 may be removed from the mold per step 24 of FIG. 1, and further illustrated as separation 600 from the mold 202 as shown in FIG. 6, per conventional molding techniques. The molded structure 602 formed from the cured layers of polyurea can then be processed via conventional finishing techniques and inspected for quality to make the finished product shown in FIG. 7 and thereafter utilized as desired.

[0038] Advantageously, molded objects formed by the methods of the present invention can be rapidly produced and can further be made on a large-scale basis without the need to utilize reinforcing or other support structures, although such structures can be incorporated if desired and/or to impart greater structural strength. Moreover, the processes of the present invention when utilized to manufacture spas, swimming pools and the like, dramatically expedite manufacturing and multiple pools can be made in a single day, as opposed to a multi-day manufacturing process required for fiberglass pool and spa production. Along those lines, such molded pools and spas, once formed, are ready for shipping and installation as per conventional fiberglass pools and spas. Not only are such molded spas/pools ready for installation into the ground and receive water, the combination of polyurea materials, like fiberglass spas/pools, are capable of withstanding expansive and contracting soil, varying weather conditions and resistance to UV radiation to a degree and for a longevity believed to be at least equal to pools and spas manufactured from fiberglass.

[0039] The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including various ways of applying multiple layers of polyurea coatings upon a mold or substrate to produce a molded object as contemplated herein, which need not be limited in any way to swimming pools, spas and the like. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.