An insect abatement system prevents adhesion of insect debris to surfaces which must be kept substantially free of insect debris. An article is coated with an insect abatement coating comprising polyorganosiloxane with a Shore A hardness of less than 50 and a tensile strength of less than 4 MPa. A method for preventing the adhesion of insect debris to surfaces includes the step of applying an insect abatement coating to a surface which must be kept substantially free of insect debris

Burnell, Timothy Brydon

Spiro, Clifford Lawrence

Wengrovius, Jeffrey Hayward

NASA Technical Reports Server

United States Patent 1191 [11] Patent Number: 5,685,506 
Spiro et al. [451 Date of Patent: Nov. 11, 1997 
[54] INSECT ABATEMENT SYSTEM 
p5] Inventors: Clifford Lawrence spiro, Niskayuna; 
Timothy Brydon Burnell, 
Schenectady; Jeffrey Hayward 
Wengrovius, Scotia, all of N.Y. 
[73] Assignee: General Electric Company, 
Schenectady, N.Y. 
1211 Appl. No.: 414,167 
[22] Filed Mar. 31,1995 
[51] InL C1.6 .............................. B32B 7/02; B32B 25/20; 
B64C 21/10 
[52] U.S. C1. ........... 244/121; 2441133; 244J134 A, 
2441134 E; 4271407.1; 4281336; 4281447; 
4281450; 428i45 1 
[58] Field of Search ..................................... 2441133, 126, 
2441134 A, 134 E, 121; 4281447, 450, 451, 
215.336; 4271407.1 
[56l References Cited 
U.S. PATENT DOCUMENTS 
2,!567,804 9/1951 Davies ................................ 2441134 A 
5,187,015 2/1993 Yorkgitis et al. ............ 428/447 
FOREIGN P m  DOCUMENTS 
0369259 1111989 European Pat. off. . 
2078544 1/1982 United Kingdom. 
2240728 8/1991 United Kingdom. 
2244715 12/1991 United Kingdom. 
9306180 41993 WIPO. 
OTHER PUBLICMIONS 
C.C. Croom and B.J. Holmes, “Flight Evaluation of an 
Insect Contamination Protection System for Laminar Flow 
Wings”, SAE 850860, 1985. 
EX. Worthmann, “A Possiblility of Avoiding Surface 
Roughness Due to Insects”, NASA TM 77419, Mar. 1984. 
0. Yi, N.S. Eiss and J.P. Wightman. “A Fundamental 
Approach to the Sticking of Insect Residues to Aircraft 
Wings”, NASA-CR-183041, Sep. 1988. 
N. Wes Gimbert, “A Study of Insect Contamination of 
Laminar Flow Surfaces”, Aug. 13, 1993. 
Encyclopedia of Polymer Science and Engineering, vol. 15, 
PrimuTy Examiner-Paul J. Thibodeau 
Assistant Examiner-D. Lawrence Tarazano 
Attorney, Agent, or Firm-William H. Pittman 
1571 ABSTRACT 
An insect abatement system prevents adhesion of insect 
debris to surfaces which must be kept substantially fiee of 
insect debris. An article is  coated with an insect abatement 
coating comprising polyorganosiloxane with a Shore A 
hardness of less than 50 and a tensile strength of less than 4 
MPa. A method for preventing the adhesion of insect debris 
to surfaces includes the step of applying an insect abatement 
coating to a surface which must be kept substantially free of 
insect debris. 
pp. 273-289, 1985. 
9 Claims, No Drawings 
https://ntrs.nasa.gov/search.jsp?R=20080004616 2019-08-30T02:44:41+00:00Z
5,685,506 
1 2 
INSECT ABATEMENT SYSTEM a. a surface, and, 
an insect abatement coating deposited onto said surface, 
This invention was made with government support under wherein said insect abatement coating comprises a poly- 
Contract No. NAS3-26617 awarded by NASA. The govern- organosiloxane with a Shore A hardness of less than 50 and 
ment has certain rights in this invention. 5 a tensile strength of less than 4 MPa. 
In accordance with another aspect of the present 
Background of the Invention invention, there is provided a method of insect abatement 
This inventionrelates to an insect abatement article. More comprising applying an insect abatement coating to a 
specifically, it relates to an article which prevents rupture of surface, wherein said insect abatement coating comprises a 
insects and adhesion of the resultant debris to surfaces which 10 polyorganosdoxane with a Shore A hardness of less than 50 
must be kept substantially free of insect debris. It further and a tensile strength of less than 4 MPa. 
relates to a method for preventing the adhesion of insect 
debris to surfaces. Description of Preferred Embodiment 
TO reduce drag on an &craft and to increase fuel The article disclosed in this invention includes a surface 
efficiency, a i r a d  surface roughness must be -zed l5 and an insect abatement coating deposited onto said surface. 
One conbributor to aircraft surface roughness is insect con- The method of the Current invention requires an 
tamination. When the insect collides with the aircraft, the insect abatement coating to a surface. 
insect cuticle ruptures. Insect fluid bonds the ruptured Any surface where fluid flow must be maintained with as 
cuticle to the surface forming a disturbance that increases little surface friction and drag as possible can be coated with 
drag. To ensure smooth, uninterrupted air flow across the 2o the insect abatement coating of the present invention. Such 
aircraft surface, a typical limit on surface uniformity is 0.05 surfaces include certain areas on the bodies of airplanes. 
mm. Debris from insect impact is often several times this Certain surfaces of the aircraft, such as the leading edges of 
height. This debris increases air flow turbulence and wings, empennages and inlet cowls, are particularly suscep- 
decreases fuel efficiency. tible to insect accumulation. These surfaces are prone to 
Insat contamination usually occus on aircraft at altitudes 25 collecting insect debris a~ the insects collide with the 
below about 150 m, corresponding to take-off and initial aircraft. 
climb. Insects can also be accumulated during landing and Surfaces that would benefit fiom the present invention are 
will impact subsequent flights unless they are removed while also found on land vehicles, particularly high speed racing 
the plane is on the ground. cars. and any other land vehicles for which speed and a low 
There have been nmerous proposed solutions to this 30 COeffiCiellt Of drag are @Ol’hIlt. These SurfaceS include the 
insect contamination. The use of a silicon foam rubber had front bumper section, side panel, hood, roof and any other 
been suggested in a r e p a  by F. X. w o m m  entifled “A Surface Of a land Vehicle where it is important t0 I l l a i I l ~  
Possibility of Avoiding Surface Roughness Due to Insect”, Smooth, unintermpted air flow. 
NASA TM-77419, March 1984. However, it was docu- 35 Adhesion of insect debris to surfaces that are transparent 
mented in the report that the silicon foam rubber exhibits reduces visibility, as well as increasing drag. Insect debris 
rain erosion problems. In their report, ‘Tnvestigation of adhesion can be minimized and even eliminated by the 
Factors Affecting the Sticking of Insects on Aircraft Wing application of a substantially transparent insect abatement 
Surface”, (NASACR-183041, Sept. 1988), 0. Yi, N. S. Eiss coating of the present invention to such surfaces. These 
and J. I? Wightman documented insect adhesion to various surfaces include the transparent face shield of protective 
materials. They studied materials such as fluoroelastomer, helmets, such as a motorcycle helmet, and the window or 
synthetic rubber, polytetrafluoroethylene, polyurethane, sty- windshield of a land vehicle. 
rene butadiene rubber, polyvinyl fluoride, polyester, Suitable insect abatement coatings for the present inven- 
polyethylene, polycarbonate and chlorotetrafiuoroethylene. tion comprise a polyorganosiloxane with a Shore A hardness 
A synopsis of attempts to eliminate insect contamination, 45 of less than 50 and a tensile strength of less than 4 MPa. 
written in 1985, can be found in “Flight Evaluation of an Shore A hardness is measured using the method of ASIU 
Insect Contamination Protection System for Laminar HOW D638, which is incorporated herein by reference. Tensile 
Wings”, SAE 850860, by C. C. Croom and B. J. Holmes, in  strength is determined via ASTM method D2240, which is 
Table 1, page 14. Several coatings not recommended in the incorporated herein by reference. Materials with higher 
earlier works are listed as possible alternatives in “A Study 50 hardness and greater tensile strength promote adherence of 
of Insect Contamination of Laminar Flow Surfaces”, dated insect debris to the surface. For use in the instant invention, 
8/13/93, by N. Wes Gimbert. preferable materials include a two-part, room temperature 
Insect contamination is also a concern in the sport of high vulcanized, condensation cured polydialkylsiloxane. More 
speed auto racing. As with aircraft, any surface roughness on preferably, the insect abatement coating comprises polydh- 
the body of the land vehicle that increases surface friction 55 ethylsiloxane. Such polydhethylsiloxanes include materi- 
and drag negatively impacts performance. The article of the als marketed by General Electric Company under the trade 
instant invention can prevent the adherence of insect debris names Exsd@2200, FtTV 11 and W 21. 
to the car, thereby reducing drag and improving racing It preferred that the insect abatement coating be substan- 
results. tially free of voids. The preferred material of the instant 
The present invention a n  also be used to inhibit insect 60 invention is in contrast to the foamed material of the prior 
adhesion to windshields. windows and any transparent sur- art. The insect abatement coating of the present invention 
faces. Adherence of insect debris to such surfaces reduces preferably comprises a material which is not foamed, and 
visibility, as well as increasing surface friction and drag. therefore is substantially fiee of air bubbles or voids. 
When the insect abatement coating is applied to a trans- 
65 parent surface, it is important that the insect abatement 
coating is also substantially transparent. Such transparent 
polydiwlsiloxanes are well known in the ar t  
Summary of the Invention 
In accordance with the present invention, there is pro- 
vided an insect abatement article comprising: 
5,685,506 
3 4 
The insect abatement coating can be applied to the surface EXAMPLE 3 
by any method, including painting, spraying, and dipping. 
surfaces can be of any used to manufacture Using the wind tunnel and insect delivery system of 
articles such as aircraft wings, empennages, inlet cowls, Example 1, house flies were deposited onto a plate coated 
automobile bodies, windows, windshields, and face shields. 5 with 0.13 mm of Exsil2200 room temperature vulcanized 
The possible materials include steel, aluminum, plastic, and silicone rubber. Profilometry indicated that some of the 
composite materials, including resin-impregnated fiberglass. insect debris that adhered to the coated plate was in excess 
Depending on the material of the surface, it may be Of 0.150 
necessary to apply a primer to the surface prior to applying 
the insect abatement coating to ensure adhesion of the insect 10 
abatement coating to the surface. Such primers are well 
known in art. mey include moisture curable grafted 
copolymers, which comprise p~y~alky~siloxane d one or 
more ethylenically unsaturated monomers, and epoxy 
primers, which a 
rial and a grafted 
copolymers and epoxy primers can be used individually or 
in conjunction with one another or with other primers. 
Insect abatement coating thicknesses can range from 0.02 
to 10 m The preferred thickness is 0.15 to 0.5 111111. 
skilled in the art to understand more clearly and practice the ss wte hdustfial ~ b ~ ~ i ~ ~  unit ~ ~ & l  K grit blaster was 
present invention. These examples should not be considered to 0.5 ma. ~n average of 15 grams/-ute of 
as a fitation upon the scope of the Present i~ent ion .  but 25 #8 (50 microns) silicon carbide powder was accelerated 
merely as being illustrative and representative thereof. through a jet nozzle onto the coated plate. The coating was 
In each of the following examples. the SaInPk was examined microscopically before and after grit blasting. No 
considered to have passed if the insect debris was less than change was noted in the coated surface. There was no 
0.05 high. Example 1 describes how insect debris in damage to the Exsil silicone rubber surface. It remained 
excess of the acceptable height limit adhered to an uncoated 30 shiny and without evidence of surface pitting or tearing. 
stainless steel plate. The article of the instant invention is 
described in Example 2, which showed how the height of the 
insect debris was reduced as a result of coating the plate. In 
Example 3. a thin layer of the insect abatement coating, 
which was less than the preferred thickness,resulted in some 35 
insect debris higher than the acceptable limit. However, even 
with the thin layer, the amount of insect debris that adhered 
to the coated plate was less than the amount that adhered to 
the uncoated plate of Example 1. In Example 4, a material 
with Shore A hardness in excess of 50 and a tensile strength 40 
greater than 4 MPa allowed insect debris higher than the 
acceptable limit of 0.05 mm to adhere to the plate. Example 
5 detailed a new and unexpected result of the present 
invention: the insect abatement coating's resistance to grit 
erosion. 
high. 
EXAMPLE 4 (CONTROL) 
Using the wind tunnel and insect delivery system of 
Example 1, house flies were deposited onto a plate coated 
with OS mm Of s6O room temperature vulcanized 
is silicone rubber. This mat& exhibits a Shore Ahardness of 
60 and a tensile strength of 4.6 m a .  profilometry indicated 
that much of the insect debris that adhered to the coated plate 
was in excess of 0.150 mm high. 
epoxy function&ed base 
catalyst. Such moisture 
EXAMPLE 5 2o 
The are presented to those A metal panel was coated with 0.5 mm of Exsil 2200. An 
mat is claimed is: 
1. An insect ab&ement article comprising: 
a an aircraft surface selected from the group consisting of 
aircraft wings, empennages and inlet Cowls, and, 
b. an insect abatement coating deposited onto said 
surface, wherein said insect abatement coating com- 
prises a room temperature vulcanized. condensation- 
curedpolyorganosiloxane having a Shore Ahardness of 
less than 50 and having a tensile strength of less than 
4 MPa. 
2. An article in accordance with claim 1, wherein said 
surface comprises materials selected from the group con- 
sisting of steel, aluminum and plastic. 
3. An article in accordance with claim 1, wherein said 
polydialkylsiloxane comprises polydimethylsiloxane. 
4. An article in accordance with claim 1, wherein said 
insect abatement coating is non-foamed. 
5. An article in accordance with claim 1, wherein said A wind tunnel was constructed that was equipped with an insect delivery system. Houseflies were deposited at an so insect abatement coating is o.02 mm to 
insect impingement velocity of 90 4 s  onto a 304 stainless 6. An article in accordance with claim 1, wherein said 
insect abatement coating is 0.15 mm to 5 mm thick. steel plate. The insect debris was analyzed by profilometry. One hundred percent of the insect impacts with the plate ,. A method of making an insect abatement aircraft resulted in rupture of the insects and deposition of debris. surface, applying a insect abatement coating to The maximum reading possible with the profilometer was 
55 an aircraft surface selected from the group consisting of 0.36 mm. This debris measured at least 0.36 mm. Visual aircraft wings. empennages, and inlet cowls, wherein said inspection indicated that the height of the debris was in insect abatement coating a two part, room tem- 
pe ra tu re  vu lcan iz ing  condensa t ion  cu rab le  excess of 0.51 mm. 
polydialkysiloxane, which upon curing has a Shore A hard- 
60 ness of less than 50 and a tensile strength of less than 4 MPa 
8. A method in accordance with claim 7 wherein said 
polydialkylsiloxane comprises polydimethylsiloxane. 
9. A method in accordance with claim 7 further compris- 
ing the step of applying a primer to a surface, wherein said 
45 
EXAMPLE 1 (CONTROL) 
thick. 
EXAMPLE 2 
Using the wind tunnel and insect delivery system of 
Example 1, house flies were deposited onto a plate coated 
with 0.5 mm of Exsil 2200 room temperature vulcanized 
silicone rubber. This material exhibits a Shore A hardness of 
34 and a tensile strength of 2 m a .  Profilometry indicated 65 insect abatement coating is applied onto said primer. 
that the insect debris that adhered to the coated plate was less 
than 0.02 mm high. * * * * *  


Insect abatement system

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server