Patterned bonding of encapsulation material to an insulation assembly

An insulation assembly includes an elongated batt of fibrous insulation material having a top end and a bottom end, and a facing secured on a major surface. The facing is secured to the major surface by a series of spaced apart adhesive ribbons, wherein the adhesive ribbons are oriented generally transversely of the insulation assembly, and are nonlinear in a generally downwardly-oriented concave shape.

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION 
This invention relates to insulation products, and in particular those 
insulation products of the type suitable for insulating buildings. More 
specifically, this invention pertains to insulation products enclosed in 
encapsulation material to assist in handling the insulation products. 
BACKGROUND OF THE INVENTION 
Fibrous insulation is typically formed by fiberizing molten material and 
depositing the fibers on a collecting conveyor. Most, but not all fibrous 
insulation products contain a binder material to bond the fibers together, 
forming a lattice or network. The binder gives the insulation product 
resiliency for recovery after packaging, and provides stiffness and 
handleability so that the product can be handled and applied as needed in 
the insulation cavities of buildings. The fibrous insulation is cut into 
lengths to form insulation products, and the insulation products are 
packaged for shipping. 
One typical insulation product is an insulation batt, usually about 8 feet 
long, and generally suitable for use as wall insulation in residential 
dwellings, or as insulation in the attic and floor cavities in buildings. 
In many insulation applications a vapor barrier is needed on one side or 
face of the insulation to prevent moisture-laden air from the warm 
interior of the dwelling from entering the insulation. Otherwise, the 
water vapor in the warm interior air cools and condenses within the 
insulation, thereby creating a wet insulation product which can have 
difficulty performing at its designed efficiency. Vapor barriers are 
typically created with a layer of asphalt in conjunction with a kraft 
paper or foil facing. Vapor barrier insulation products are commonly used 
to insulate walls, floors or ceilings that separate a warm interior space 
from a cold exterior space. 
There are some insulation product requirements that call for insulation 
that is not vapor impermeable, but rather allows water vapor to pass 
through. For example, retrofit insulation products designed for adding 
additional insulation material on top of existing attic insulation should 
not have a vapor barrier. Also, insulation for wall cavities where the 
wall will have a separate full wall vapor barrier, such as a 4.0 mil 
polyethylene film on the interior or warm side of the wall, will not 
require a vapor barrier on the insulation product. 
Recent advances in manufacturing insulation products have resulted in 
insulation materials that rely on encapsulation layers or films for 
containing and handling purposes, and do not require any binder material 
to bond the insulation fibers to each other. The encapsulation is 
particularly advantageous for binderless products or low binder products, 
although encapsulation provides benefits for many types of bindered 
products as well. An example of an encapsulated binderless product is 
disclosed in U.S. Pat. No. 5,227,955 to Schelhorn et al. Further, as 
disclosed in U.S. Pat. No. 5,545,279 to Hall et al., the insulation 
material can be encapsulated in an in-line process. The primary use for 
such encapsulated insulation products is attic insulation, although this 
type of insulation product can also be used in wall cavities or in 
underfloor ceiling cavities. 
When applying encapsulation material to a fibrous batt the encapsulation 
material is attached to the fibrous batt by an adhesive layer or strip, 
such as a strip of hot melt adhesive applied in liquid form during 
manufacture of the insulation product. For example, the above-mentioned 
U.S. Pat. No. 5,277,995 to Schelhorn et al. discloses an encapsulated batt 
with an encapsulation material adhered with an adhesive that can be 
applied in longitudinal stripes, or in patterns such as dots, or in an 
adhesive matrix. The Schelhorn et al. patent also discloses that an 
alternative method of attachment is for the adhesive layer to be an 
integral part of the encapsulation film, which, when softened, bonds to 
the fibers in the batt. 
A critical product attribute for building insulation products is the 
ability to resist or slow down the propagation of flames during a fire. It 
is important that building materials in general not be vehicles for rapid 
spread of flames or fire from one part of a building structure to another. 
Therefore, most building materials must meet flame spread limitations. A 
commonly used measure of the flame spread characteristics of a product is 
the ASTM E84 Tunnel Test for surface burning characteristics. In this test 
method a fire is generated at one end of a fire tunnel and the time 
required for the flames to spread 25 feet along the tunnel is measured. In 
another version of the test, the absolute distance along which the flames 
spread is measured. Another currently used test for the ability of 
insulation products to retard the spread of flames is the ASTM Radiant 
Panel Test. This test measures the flame spread characteristics of 
products subjected to radiation from a hot radiant panel suspended above 
the test specimen. 
Various techniques have been proposed to reduce the flame spread of 
insulation products. One proposed solution is to incorporate fire 
retardant materials into the facing or encapsulation materials. Another 
method is to use an inorganic facing material, such as a foil material. 
Another solution is to employ inorganic adhesives to bind the 
encapsulation material to the fibrous batt. While some of these solutions 
can be effective in reducing the flame spread to acceptable levels, these 
solutions are generally relatively expensive. 
It would be advantageous if there could be developed an economically 
acceptable means for reducing the flame spread of insulation products. 
Such insulation products should exhibit sufficiently low flame spread 
characteristics as to satisfy industry safety criteria, and should not 
appreciably raise the manufactured cost of the insulation product. 
SUMMARY OF THE INVENTION 
The above objects as well as other objects not specifically enumerated are 
achieved by an insulation assembly including an elongated batt of fibrous 
insulation material having a top end and a bottom end, and a facing 
secured on a major surface. The facing is secured to the major surface by 
a series of spaced apart adhesive ribbons, wherein the adhesive ribbons 
are oriented generally transversely of the insulation assembly, and are 
nonlinear in a generally downwardly-oriented concave shape. 
According to this invention, there is also provided an insulation assembly 
including an elongated batt of fibrous insulation material having a top 
end and a bottom end, and a facing secured on a major surface. The facing 
is secured to the major surface by a series of spaced apart adhesive 
ribbons, wherein the adhesive ribbons are oriented generally transversely 
of the insulation assembly. The adhesive ribbons are nonlinear in a 
generally downwardly-oriented concave shape, and include opposed left and 
right portions connected together and oriented along generally straight 
lines. 
Various objects and advantages of this invention will become apparent to 
those skilled in the art from the following detailed description of the 
preferred embodiment, when read in light of the accompanying drawings.

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION 
While the description and drawings disclose insulation assemblies of 
fiberglass insulation, it is to be understood that the insulation material 
can be any compressible fibrous insulation material, such as mineral wool. 
As shown in FIG. 1, the prior art encapsulated insulation assembly 10 is 
shown with the encapsulation material 12 partially cut away so that the 
adhesive ribbons 14, which bond the encapsulation material to the batt 16, 
are exposed. The adhesive ribbons are a hot melt adhesive. During a flame 
spread test in which the bottom 18 of the insulation assembly is exposed 
to a flame, the adhesive ribbons do not hinder the spread of flames from 
the bottom to the top 20 of the insulation assembly. 
In an alternative form of an encapsulated insulation assembly 22 of the 
prior art, as shown in FIG. 2, the adhesive ribbons 24 are arranged on the 
batt 26 to adhere the encapsulation material 28 to the batt. The adhesive 
ribbons 24 are oriented on a diagonal, in a zigzag pattern. While this 
pattern of adhesive differs from that of FIG. 1, during a flame spread 
test in which the bottom 30 of the insulation assembly 22 is exposed to a 
flame, the adhesive ribbons 24 would not be expected to substantially 
hinder the spread of flames from the bottom to the top 32 of the 
insulation assembly. 
As shown in FIGS. 3 and 4, the insulation assembly of the invention is 
indicated at 34, and is made of an elongated insulation batt 36 and 
encapsulation material 38. The insulation assembly has a bottom end 40 and 
a top end 42. The manufacture of the glass fiber insulation batts 36 is 
well known technology, and those skilled in the art will be aware of 
several conventional methods for producing such batts. The glass fiber 
batts are preferably comprised of a light density insulation material, 
having a density within the range of from about 0.3 to about 1.0 pounds 
per square foot (pcf). 
The encapsulation material 38 is preferably a polymer film, such as a 
polyethylene film, although other films such as a polypropylene film can 
be used. Coextruded films could also be used, with the two layers of the 
coextruded film having different softening points. The encapsulation 
material is preferably less than about 1.0 mil in thickness, and more 
preferably less than about 0.5 mil in thickness. The encapsulation 
material can be applied to the insulation batt by any suitable process. 
Apparatus suitable for directing and guiding the encapsulation material 
onto the glass fiber pack is disclosed in the above-mentioned U.S. Pat. 
No. 5,545,279 to Hall et al., which is hereby incorporated by reference. 
The encapsulation material 38 is adhered to a major surface 44 of the 
insulation batt 36 by a series of spaced apart adhesive ribbons 46. The 
adhesive ribbons are oriented generally transversely of the insulation 
assembly, i.e., generally perpendicular to the longitudinal axis 48 of the 
insulation assembly. The ribbons are bent or curved to present a 
downwardly concave shape. As shown, the ribbons can be in a shape of a 
chevron, with angled left portion 52 and angled right portion 54, forming 
an apex 56. Although the opposed left and right portions 52 and 54 are 
shown as being connected together, they may be separated. Further, it is 
to be understood that the ribbons can be provided with small 
discontinuities that can affect the path of the fire or flames along the 
line of the ribbons. The angled left and right portions 52 and 54 form an 
angle that is preferably within the range of from about 120 degrees to 
about 170 degrees, although other angles may also be effective. Although 
not shown, the left and right portions can extend all the way to the edge 
of the batt. The number of adhesive ribbons and their spacing can vary. 
Preferably, the adhesive ribbons are spaced apart by at least 6 inches, 
and more preferably by a distance within the range of from about 10 to 
about 18 inches. 
During a flame spread test, the bottom end 40 of the insulation assembly 34 
is exposed to a flame, the flame attacks the encapsulation material 38. 
Regardless of whether or not the encapsulation material itself provides 
combustible material, the flames eventually reach the lowermost adhesive 
ribbon 46. Because of the downwardly concave shape of the adhesive ribbon, 
the advance of the burning of the left portion 52 will be toward the 
center of the insulation assembly, and the advance of the burning of the 
right portion 54 will be toward the center. When the burning traveling 
along the line of the left portion 54 meets the burning traveling along 
the line of the right portion, there will be a dramatic, sudden lack of 
fuel, and the advance of the fire or flames from the lowermost adhesive 
ribbon to the next higher adhesive ribbon will be prevented or at least 
delayed. In other words, the burning on the left and right will be curled 
or directed towards each other to retard the extension of the flames 
beyond the adhesive ribbon. Therefore, a series of spaced apart, 
chevron-shaped adhesive ribbons 46 will advantageously hinder the 
propagation or spread of flames from the bottom end 40 to the top end 44 
of the insulation assembly. 
As shown in FIG. 7, a wall section, indicated at 60, includes several wall 
cavities 62 defined by studs 64, a header, not shown, a footer 66, and 
sheathing material 68. An insulation assembly 34 of the invention, shown 
partially cut away, is placed in one of the wall cavities 62 to provide an 
insulation assembly that can significantly retard the upward spread of 
flames from the bottom end 40 of the insulation assembly. When the 
insulation assembly 34 is positioned in a wall cavity as shown in FIG. 7, 
the adhesive ribbons are in a preferred orientation to inhibit the flames 
of a fire starting at the bottom end of the insulation assembly, with the 
generally downwardly concave shape oriented toward the source of the fire. 
Since it is not always possible to predict the origin or direction of a 
fire, there may be situations where the generally downwardly concave shape 
is oriented away from the source of the fire. It is believed that the 
transverse orientation of the adhesive ribbons would still substantially 
inhibit the spread of flames. 
As shown in FIG. 5, the insulation assembly 72 includes curved adhesive 
ribbons 74 placed on the batt 76. The curved ribbons are generally 
downwardly concave in shape, with the concave portion facing the bottom 
end 78 of the insulation assembly 72. The adhesive ribbons 74 include left 
and right portions 80 and 82, respectively, oriented along generally 
curved lines. During a flame spread test the advance of the burning of the 
left portion 80 and the right portion 82 will be toward each other, and 
the propagation of the flames will be curled or directed towards each 
other to retard the extension of the flames beyond the adhesive ribbon. 
Therefore, a series of spaced apart, curved adhesive ribbons 34 will 
advantageously hinder the upward propagation or spread of flames from the 
bottom end 78 of the insulation assembly. Although the left and right 
portions 80 and 82 are shown as connected, they can be separated. 
As shown in FIG. 6, the insulation assembly 86 includes double curved 
adhesive ribbons 88 placed on the batt 90. Each of the curved sections 92 
of the double curved ribbons is generally downwardly concave in shape, 
with the concave portion facing the bottom end 94 of the insulation 
assembly 86. The double curved ribbons 88 are preferably generally 
symmetric with respect to the longitudinal axis 96 of the insulation 
assembly. During a flame spread test the advance of the propagation of the 
flames will be curled or directed towards each other, in a manner 
described above with respect to FIG. 5, to retard the extension of the 
flames beyond the adhesive ribbon. Therefore, a series of spaced apart, 
double curved adhesive ribbons 88 will advantageously hinder the upward 
propagation or spread of flames from the bottom end 94 of the insulation 
assembly. 
As shown in FIG. 8, the insulation assembly 100 is nearly identical to the 
insulation assembly 34 illustrated in FIGS. 3 and 4. Insulation assembly 
100 includes chevron shaped adhesive ribbons 102 placed on the batt 104. 
The ribbons are generally downwardly concave in shape, with the concave 
portion facing the bottom end 106 of the insulation assembly 100. The 
adhesive ribbons 102 include left and right portions 108 and 110, 
respectively, oriented along generally straight lines. The ribbons 102 
extend from edge 112 to edge 114 of the major face 116 of the batt 104, 
and are generally centered about longitudinal axis 118. 
The principle and mode of operation of this invention have been described 
in its preferred embodiments. However, it should be noted that this 
invention may be practiced otherwise than as specifically illustrated and 
described without departing from its scope.