A cat litter mat having flexible, paw-engaging projections formed
of thermoplastic polyolefin elastomer, preferably a blend of such
elastomer with low density polyethylene.
What is claimed is:
1. A cat litter mat having flexible, paw-engaging projections formed
of thermoplastic polyolefin elastomer.
2. The mat of claim 1 wherein the projections are formed of a thermoplastic
polymeric blend of 20 to 90 wt. % polyolefin elastomer and 80 to
10 wt. % polyethylene.
3. The mat of claim 2 wherein the polyethylene is low density polyethylene
having a density of 0.910 to 0.925 gm. per cc.
4. The mat of claim 2 wherein the blend contains 35 to 65 wt. %
5. The mat of any of claims 1 2 3 or 4 wherein the projections
are grasslike, having randomly oriented tips.
BACKGROUND OF THE INVENTION
This invention relates to a cat litter mat.
In urban environments such as apartments and residential homes,
trained felines, such as cats and like animals, deposit their waste
in a litter box. Litter on which the animal waste is deposited is
typically granulated absorbent material. In using the box the litter
often becomes attached to the cat's paws, and is dragged from the
box and messily deposited on the floor in the home or apartment,
and, if the occasion arises, sometimes even buried. Also, after
use a cat often kicks the litter around in the box which can result
in ejecting it onto the surrounding floor.
Mats or pads on which the cat steps on exiting the box are known.
Their purpose is to dislodge litter from the cat's paws as it walks
across the mat to thereby avoid dragging it about the surrounding
area. Some prior art mats have short, spike-like projections intended
to enter and spread the soft pads on the underside of the cat's
paws to allow litter wedged between and on the pads to fall onto
the mat before the cat reaches its edge. Cats paws, however, are
quite sensitive and they dislike standing on rigid projections jabbing
their paws with the result that the cat frequently shies away from
using the liter box altogether.
It would be desirable to provide an animal liter mat more amenable
to the liking of the animal using it.
SUMMARY OF THE INVENTION
Now, improvements have been made in animal litter mats which overcome
shortcomings of the prior art.
Accordingly, a principal object of this invention is to provide
an improved waste-containment mat for an animal such as a cat.
Other objects will in part be obvious and will in part appear from
the following description and claims.
These and other objects are accomplished by providing a cat litter
mat having flexible, paw-engaging projections formed of thermoplastic
polyolefin elastomer. The projections are preferably formed of a
thermoplastic polymeric blend of 20 to 90 preferably 35 to 65 wt.
% polyolefin elastomer and 80 to 10% preferably 65 to 35 wt. % polyethylene--preferably
low density polyethylene.
BRIEF DESCRIPTION OF THE DRAWINGS
In describing the overall invention, reference will be made to
the accompanying drawings wherein:
FIG. 1 is a perspective view of a waste containment system for
a cat illustrating a cat litter mat according to the invention;
FIGS. 2-4 are fragmentary perspective views of cat litter mat embodiments
of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings, waste containment system in FIG. 1 comprises
cat litter mat 10 resting on a flat surface such as a floor adjacent
litter compartment 12. Compartment 12 containing litter, not shown,
is a covered box having opening 14 large enough for passage of cat
13. Compartment 12 may differ in configuration from and vary widely
from that shown; e.g. it may be open top or closed top and only
functions to contain litter and animal waste.
Mat 10 is a three dimensional, one piece structure comprising a
multitude of soft, paw-engaging projections 18 integral with and
at least in part generally extending perpendicularly up (on the
order of about 3/8 to 5/8 in.-0.95 to 1.6 cm) from base 16. Optional
backing 20 of fabric or plastic film is bonded thermally or with
an adhesive to the underside of base 16 after molding of mat 10.
In the illustrated embodiments, projections 18 are evenly spaced
from each other and arranged in mutually perpendicular rows on base
16. In FIG. 3 projections 18 are solid whereas in the preferred
form of FIG. 2 they are a multitude of vertically short cup-like
bases 22 from each of which projects clusters of blade-like extensions
24 which are rectangular in cross section. In the FIG. 4 embodiment
the upper end portions or tips 25 of the blade-like extensions 24
of FIG. 2 are disordered in orientation and irregularly project
in many directions as shown. The FIG. 4 structure is formed by texturing
the FIG. 2 version in the final step of the mat fabrication process
to be further described.
Cat litter mat 10 having a multitude of projections 18 extending
from a base 16 may be shaped differently from those shown. For example,
projections 18 may be randomly positioned in a disordered pattern
on the base, may be individually configured differently, e.g. circular
or the like in cross section and may be assembled from a plurality
of components instead of being one piece --e.g. the projections
may be separately formed of one material in a grid and then bonded
to a planar base, optionally of a different material.
According to the invention, paw engaging projections 18 of cat
liter mat 10 are either entirely or partially formed of thermoplastic
polyolefin elastomer. Preferably the entire mat including projections
18 are of a blend of molded thermoplastic polymer of 35 to 65 wt.
% polyolefin elastomer and 65 to 35 wt. % of another thermoplastic
material such as polyethylene, preferably low density polyethylene
having a density of 0.910 to 0.925 gm/cc. To facilitate forming
the textured embodiment of FIG. 4 the elastomeric content of the
polymeric blend is about 50 to 60 wt. %.
Usable polyolefin, e.g. polyethylene, elastomers typically have
a density of 0.820 to 0.905 gm/cc and are commercially available
from Dupont--Dow Elastomer L.L.C. of Wilmington, Delaware as Engage.TM.,
specifically type EG 8200. Also usable as polyolefin elastomer is
Exact.TM., specifically type 4033 from Exxon Chemical Co.
Mat 10 is fabricated by conventional cyclic batch injection molding
wherein molten thermoplastic is forcibly injected into a closed
mold conforming to the finished article shape, followed by cooling
of the mold to set the thermoplastic and ejection of the formed
article from the mold. Preferably injection molding is continuous
according to the method and apparatus disclosed in U.S. Pat. No.
3729364 to Doleman et al, the molding disclosure of which is
incorporated herein by reference. Briefly, in the system of that
patent the thermoplastic components to form mat 10 are dry blended,
optionally along with other additives such as coloring pigments,
antioxidants and the like, in a feed hopper and then fed in molten
form to an extrusion nozzle by a metering pump, screw extruder or
the like from which it is forced into recessed areas in continuously
advancing molds under varying pressure depending on size and depth
of the mold cavities. The thermoplastic material is cooled below
its solidification point and stripped away in a continuous length
from the molds. After texturing of the blade-like extensions and
application of backing 20 the continuous length is cut into appropriate
individual mat sections of about 12 in. by 18 in. (30.5 to 45.7
The soft elastomeric composition of projections 18 of mat 10 provides
the property-enhancing performance of the mat as a support for a
cat in and around litter box 12. When cat 13 walks across mat 10
relative movement between the paws and the multiplicity of projections
cause the projections to enter nooks and crannies of the paw to
spread pad portions on the downside of the paw apart so litter sticking
on or between the pads is dislodged and free to fall away by gravity
onto the mat surface thereby avoiding the cat dragging litter around
the surrounding area as it walks away from the area of the waste
containment system. With the large surface area configuration of
FIG. 4 any litter kicked out of the box by the cat is interrupted
and blocked in flight so as to fall by gravity onto the mat surface.
In addition, independently of the cat, in evaluating the type of
litter mat to purchase for an apartment, on feeling the soft projections
of the inventive mat promoted by the elastomeric content of the
blade composition, a cat owner is likely to choose the inventive
mat over stiffer prior art structures.
The preceding description is for illustration and should not be
taken as limiting. Various modifications and alterations will be
readily suggested to persons skilled in the art. It is intended,
therefore, that the foregoing be considered exemplary only and that
the scope of the invention be ascertained from the following claims.