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Description  |
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FIELD OF THE INVENTION
The present invention relates to a foam sealing tape with interlayer strip,
which is rolled up in compressed form.
BACKGROUND OF THE INVENTION
The wound interlayer strip relatively easily prevents the expansion of the
foam sealing tape which is rolled with compression. The strip consists, as
a rule, of a siliconized web of paper. When the sealing tape is unwound,
this paper is present on its adhesive-coated back, and can be removed as a
result of its anti-adhesive nature. In the case of narrow rolls of foam
sealing tape, accuracy of the position of the individual turns of the roll
is a problem in cases in which the thickness of the roll is several times
the width of the tape. The expansion force of the compressed material,
particularly in the case of improper storage, results in a deflecting
force component causing the sealing tape to bulge out on one or the other
side surface of the roll. In unfavorable cases this leads to a disruption
in the structure of the winding, and this can be true of entire shipments.
If the material wound is, for instance, foam sealing tape of delayed
resilience, this material practically can no longer be used.
The object of the invention is to eliminate this drawback and by simple
means to improve the preciseness of the position of the windings of a foam
sealing tape of this type, in which connection the tensile stress of the
winding which results in the compression can even be further increased.
SUMMARY OF THE INVENTION
According to the invention, at least one wide surface (4') of the
interlayer strip (4) is provided with elevations (9) which press into the
sealing tape (8).
As a result of this development, a foam sealing tape of this type which is
of increased value in use is obtained. While retaining or increasing the
space-saving compression, the individual winding layers are held securely
against each other. Even improper storage will no longer lead to loosening
of the winding. The elevations which extend into the foam structure lead,
rather, to a securing of the winding layers in correct position which,
however, on the other hand, does not interfere with the unwinding. The
elasticity inherent in the material promotes interlocking engagement which
is aimed at. The longitudinally oriented tear strength of plastic tape
assures even better conditions for use than paper tapes. It is furthermore
advantageous if the elevations, which are located on the wide surface
(4'), are developed as knobs or bumps. These knobs can easily be produced
on the interlayer strip. Due to the fact, furthermore, that the wide
surface (4'), provided with the elevations (9), of the interlayer strip
(4) of plastic of high tensile strength does not stick to adhesive and
that a layer of self-sticking pressure-sensitive adhesive (5) is located
between the interlayer strip and the foam, a larger total adhesive surface
is obtained as a result of nest- or notch-like supplies of adhesive within
the impressed depression zones formed by the elevations. In the case of
resilient foam material which does not have delayed resilience, when the
interlayer strip is removed and the foam material expands, the depressions
(10) may then push out protruding daubs (5b) (FIG. 3A) of adhesive
corresponding to the number of elevations (9) projecting beyond (now
above) the plane (5a). On the other hand, in the case of a foam sealing
tape (8) of delayed resilience, the notch-like supplies of the adhesive in
the depressions (10) in the rolled up compressed tape may reverse
themselves (by projecting beyond the plane (5a)) subsequently after
opening the roll and removing the interlayer strip. In either case, due to
the difference in height of sections of the adhesive layer (5), a part of
the adhesive layer always is applied first to an object so that
corrections in the position of the sealing tape when applied on the object
are initially possible. In one case (the non-delayed resiliency foam), a
full-surface adhesive bond is obtained by a subsequent firm pressing-on of
the tape, while in the other case (delayed resiliency foam) it is obtained
by the gradual, time-delayed reversal of the depressions produced by the
elevations or knobs.
If the elevations (9) are developed as protrusions (11) which form
depressions on the opposite side, a non-shiftable binding is optimized
since protrusions of the next turn of the sealing tape force themselves
into the depressions. Such an extensively cleft ("rippled") or broken-up
deformation structure of the interlayer strip, however, also has
advantages with respect to securing the end of the tape, since the closing
of the roll is effected by use of the interlayer strip which extends
beyond the ends of the foam-sealing tape, the elevations then anchoring
themselves in the recesses in the next layer. Therefore, in practice a
small length of adhesive strip (12) is sufficient for closing the roll.
With the above and other objects and advantages in view, the present
invention will become more clearly understood in connection with the
detailed description of preferred embodiments, when considered with the
accompanying drawings, of which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a roll of wound foam sealing tape with interlayer
strip, which clearly shows the above-mentioned bulging of the wound
layers;
FIG. 2 is a cross section in the region of the interlayer strip of this
foam sealing tape, seen in compressed condition;
FIG. 3 is a corresponding view with an interlayer strip having elevations,
also in compressed condition;
FIG. 3A is a view corresponding to FIG. 3 but showing very schematically a
lower, relatively inner winding of the foam-sealing tape of non-delayed
resiliency (or of delayed resiliency a long time) after the upper,
adjacent relatively outer winding of the foam sealing tape and the
interlayer strip have been removed;
FIG. 4 is a corresponding view of a portion of FIG. 3 in expanded
condition;
FIG. 5 is a top view of a portion of the interlayer strip;
FIG. 6 is a side view looking toward the inner body of the roll in the
initial stage of winding;
FIG. 7 is a view corresponding to FIG. 6 but with several layers of tape
already wound on spirally; and
FIG. 8 is a fragmentary view of part of the periphery in the region of the
closure of the completely wound final product.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A roll inner body 3 placed on a winding mandrel is used for the winding of
an elastically compressible foam web 2, for example made of polyurethane,
which travels over a table top 1 (FIG. 6). The width of the roll inner
body corresponds to the width of the web which is fed. In the present
case, the web is a foam web of delayed resilience, the web being
impregnated with a suitable impregnation substance. Together with it, an
interlayer strip 4, for example made of polyethylene, of high tensile
strength plastic of a width at least corresponding to that of the web is
also wound on.
An adhesive polymer layer, for example such as polyvinyl acetate, of
pressure-sensitive adhesive 5 is present on the tape side between the
interlayer strip 4 and the foam web 2. From the beginning this layer of
adhesive can be adhered to the web 2. However, it is preferably initially
adhered to the interlayer strip 4 to which it can slightly stick so that
the latter is the carrier of the pressure-sensitive adhesive 5. The side
4' of the strip 4 which faces the roll inner body 3 is held in slip-free
manner, i.e. firmly, on the inner body 3 of the roll via the end section 6
of the strip 4. This is accomplished by the end section 6 which extends
beyond the end 2' of the web 2, in several layers, by utilization of the
layer 5 of pressure-sensitive adhesive carried on the strip 4 and wound
sticking fast on the roll inner body 3. Increasing the winding tension or
tightness makes the fastening stronger so that this end 6 can not come
loose. The layer 5 of pressure-sensitive adhesive thus adheres to the
outer periphery of the roll inner body 3. Additional anchoring is
unnecessary. The adhesive layer 5 also sticks to the foam web 2 relatively
much stronger than to the essentially non-stickable surface 4' of the
strip 4 so that later when the tape is to be used the strip 4 can be
removed from the adhesive 5 which remains on the foam web 2.
While winding the tape up prior to use the tangentially extending
interlayer strip 4 (FIG. 6) forms an entrance gusset E with the inner body
3 of the roll. In order to obtain favorable entrance of the foam web 2,
the roll inner body 3 has an outside diameter D which is more than twice
as great as the thickness y of the uncompressed foam material. In this way
there is always a sufficiently large entrance gusset E. Behind it the
remaining foam web 2 can now enter. Upon the rotation of the rotatably
driven roller inner body 3 in the direction of the arrow x which now takes
place, a tensile stress is produced between the upwardly moving roll inner
body 3 and the wound supply roll. This initial tension serves to compress
the incoming material. The foam web 2 is wound from its start to its end
helically or spirally onto the roll inner body 3 with constant, high
compressive pressure.
After completion of the winding, the interlayer strip 4 is wound a few
further turns on itself, thereby providing an outer wrapping 7 (see FIG.
8) with its end 6' preferably held by a small strip of adhesive tape 12.
As a result of this outer wrapping, the compressed shape of the wound
material is maintained so that no expansion in radial direction can occur.
For economical reasons, a relatively wide roll is wound, which can than,
if necessary, be divided into disk-shaped roll sections. One then has a
foam-sealing tape 8 which can be unwound as needed. As can be noted from
FIG. 1, the tape width z is then a fraction of the diameter of the roll.
The resilience of such a sealing tape is about 4 to 5 times the value of
the compressed thickness y'. In this connection y corresponds essentially
to the width z.
For the reasons mentioned in the introduction the bulging shown in FIG. 1
may occur if nothing further were provided, the layers of winding which
lie back to back to each other shifting axially. In order to prevent this,
the simultaneously wound interlayer strip according to the invention is
provided at least on one (4') of its wide surfaces 4', 4" with elevations
9 which press into the foam sealing tape 8. These elevations are
dome-shaped knobs or bumps which are located close to each other. The
height of the elevations corresponds to several times the thickness of the
foil comprising the interlayer strip 4 which is formed of plastic of high
tensile strength.
All illustrated elevations 9 point or project towards the center of the
roll. The layer 5 of pressure-sensitive adhesive is located on the knob
side 4' and therefore has a larger, extended surface than in the case of a
completely flat interlayer strip as used up to now (see FIG. 2). The
elevations 9 form corresponding increased surface indentations 10 each
having a substantially spherical surface, the base of which is the
diameter of a ball.
When the interlayer strip 4, as a result of its adhesive-repelling nature
(essentially anti-adhesive or non-stickable, for example by a coating or
cover of silicone), is pulled off from the adhesive layer 5 from which it
is easily detached, the adhesive layer 5 remains adhered to the foam web 8
thereunder. When the strip 4 is pulled off from the condition of FIG. 3
after the upper adjacent outer winding layer of tape 8, 8' of FIG. 3 has
been wound off in order to use the plastic sealing tape 8, then the
elastic foam material moves again back into its original unwound condition
basically parallel to the plane 5a corresponding to the planar portion of
the wide-side surface 4'. This has the result that the portion of the
adhesive 5 remaining thereon which was contained in the larger-surface
indentations 10 may move out of the indentations 10 (the indentations 10
previously being maintained by the projections 9 of the strip 4) and thus
now extend somewhat as protrusions or ripple accumulations 5b as nest-like
supplies of adhesive projecting now beyond (above i.e. outwardly of) said
plane 5a (FIG. 3A) forming an adhesive raster. If the foam material is not
of delayed resiliency these adhesive protrusions 5b spring up beyond plane
5a rapidly. In this way there may be obtained an adhesive pattern as in
FIG. 3A, similar to the pattern of elevations 9 and depressions 10 of FIG.
5 which permits subsequent positioning corrections of the sealing tape on
an object upon its use. Positioning corrections may be made by lightly
placing the tape on the object, since only a part (5b) of the entire
adhesive surface contacts the object. By pressing the tape harder, the
tape is immovably adhered to the object by utilizing the entire adhesive
surface.
If the foam material is, for instance, a sealing tape of delayed
resiliency, due for example to a treatment with chlora-paraffin, and with
the elevations 9 are formed as protrusions 11 forming depressions 10 on
the opposite side, then at first only the flat portions of adhesive at
plane 5a exist after the web 4 has been pulled-off (without the
protrusions 5b of FIG. 3A yet developing). These flat portions can be
placed into adhesive contact with an object on which the tape is used. The
adhesive in the depressions 10, on the other hand, due to the delayed
resiliency only later may spring up to and tend respectively to project
above the plane 5a, which is used only later on for the active adhesive
action on the object. Thus the advantage of being able to initially
correct a position of the sealing tape is present here also. Furthermore,
once again nest- or notch-like supply regions or zones of protrusions 5b
of greater accumulation of adhesive are provided.
The elevations 9, which form a highly meandering, dotted or rippled course
(FIG. 5) and which are produced by deep-drawing, however, in addition,
also have the advantage that the indentations or depressions 10 formed
thereby permit the entrance of foam material 8' (see FIG. 3) such that the
corresponding layer of foam material of a relatively adjacent outer
winding of tape 8 is also secured against sliding (relative the inner
adjacent winding of tape 8). This is achieved by penetration of the
portions 8' thereof of corresponding shape as the depressions 10 into the
depressions 10 of the adjacent inner winding of the tape 8. Such a
staggered-plane joint (i.e. interlocking tooth-like interengagement of the
adjacent surfaces of the layers 8) with the participation of both adjacent
layers of the winding layers 8 (outer and adjacent inner foam-material
sealing tape layers 8 in FIG. 3) in addition to preventing relative
slipping of the adjacent layers 8, also optimumly guarantees no bulging of
the winding. The corresponding depth of anchoring (the tooth-like
interengagement) obtained by this staggering of the planes can be
increased if the protrusions 9 extend also from the other wide surface 4"
radially outwardly (not shown in the detail of the drawings).
Upon the expansion of the successive winding layers into their original
condition by unwinding even a portion of the tape for use or even simply
removing or releasing the adhesive strip 12 (FIG. 8), the portions of foam
8' which extend into the depressions 10 of the protrusions 11 tend to pull
automatically out from same again by resiliency. This is shown in FIG. 4
in an intermediate stage. (The pores have a flater alignment more
horizontally in the compressed condition than during or after expansion
where they assume a more upwardly and downwardly enlarged shape.) Since
there is no layer of adhesive between the upper layer (actually the outer
of two layers) and the sealing tape (4, 5, 8) thereunder in FIG. 4, the
upper layer can first of all be detached from the interlayer strip 4
therebelow which in this case forms a protective covering for the lower
layer, in any event without carrying along with it this interlayer strip
4. This strip 4 via the layer 5 of pressure-sensitive adhesive therebelow,
is in somewhat, relatively stronger adhesive contact (although essentially
yet non-stickable itself) with the layer of sealing tape there (the lower
layer shown in FIG. 4).
The roughening of the interlayer strip 4 obtained, particularly by its
protrusions 9, 11, also aids the formation of the peripheral wrapping 7 in
that the elevations 9 engage into the depressions 10 of the protrusions 11
of the winding layer located below same so that they are also secured
against any tendency to slip in a direction opposite the direction of
winding. It is merely necessary to apply the small adhesive strip 12 to
the outer end of the interlayer strip and the adjacent exposed region of
the layer of the strip located below same.
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