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United States Patent [w]
Alfter et al.
[li] 4,377,614  Mar. 22,1983
 FLOOR MAT, ESPECIALLY FOR MOTOR VEHICLES
 Inventors: Franz-Werner Alfter; Hans-Ulrich
Breitscheidel, both of Siegburg, Fed.
Rep. of Germany
 Assignee: Dynamit Nobel Aktiengesellschaft, Troisdorf, Fed. Rep. of Germany
 Appl. No.: 205,253
 Filed: Nov. 10,1980
 Foreign Application Priority Data
Nov. 9, 1979 [DE] Fed. Rep. of Germany 2945285
 Int. CI.3 B32B 7/02; B32B 7/04;
 U.S. CI 428/213; 428/218;
 Field of Search 428/315, 316.6, 314.4,
428/314.8, 319.1, 319.3, 319.7, 159, 213, 218
 References Cited
U.S. PATENT DOCUMENTS
3,954,537 5/1976 Alfter et al 428/316.6
4,020,207 4/1977 Alfter et al 428/315
4,053,341 10/1977 Kleiner et al 428/316.6
4,147,828 4/1979 Heckel et al 428/315
4,259,408 3/1981 Moschter 428/315
Primary Examiner—William J. Van Balen
Attorney, Agent, or Firm—Antonelli, Terry & Wands
A floor mat is formed essentially of cross-linked polyolefin foam for the lining of the floor interiors of motor vehicles. This mat includes a cross-linked polyolefin foam floor mat base having at least one preselected surface area covered with a permanently applied floorprotecting surface layer. The layer is made up of crosslinked polyolefin foam layer and a thermoplastic polymeric film which is heatable in a high-frequency electrical field in dielectric fashion and which exhibits wear resistance superior to the cross-linked polyolefin foam or base. The cross-linked polyolefin foam base is preshaped to conform to the contours of the floor interior of a motor vehicle.
3,651,183 3/1972 Hosoda et al.
11 Claims, 7 Drawing Figures
U.S. Patent Mar. 22, 1983 Sheet 1 of 2 4,377,614
U.S. Patent Mar. 22, 1983 Sheet 2 of 2 4,377,614
FLOOR MAT, ESPECIALLY FOR MOTOR
This invention relates to a floor mat of cross-linked polyolefin foam, especially for lining the interiors of motor vehicles and to a method of forming the mat.
German Offenlegungsschrift No. 2,504,691 discloses trunk and floor mats for motor vehicles or other modes of transport, shaped in the elastic or plastic state by the application of pressure and heat, from a laminated, closed-cell and preferably chemically cross-linked polyethylene foam with a density of 30 to 200 kg/m3. These trunk or floor mats can be manufactured in either a single layer or multiple layers from polyethylene foam sheets with different densities, whereby the polyethylene foam sheet with the higher density provides a surface which is more resistant to wear.
It has been found that polyethylene foam mats with high densities or those laminated with polyethylene film do in fact suffice for many requirements, but such foam mats have not been able to withstand the stresses to which the mats are exposed in the floor area and pedal area of floor mats contacted by the occupants in passenger compartments of motor vehicles. Carpet linings in passenger compartments of motor vehicles that are reinforced in areas of high wear are known. For example, such areas may be reinforced by plastic pads, welded or glued in place, the surface of the pads being sometimes embossed.
The goal of the invention is to make floor mats from cross-linked polyolefin foams, which also have a wearresistant surface in the floor area subjected to high wear. The difficulty arises that suitable floor protective coatings made of thermoplastic plastics such as PVC cannot be reliably and permanently bonded directly by welding or gluing to cross-linked polyolefin foam in floor mats. Moreover, when making a laminate of this kind, it is also necessary to keep in mind the foam structure of the floor mat, which structure should be maintained as much as possible.
The invention solves the problem of providing a floor mat of cross-linked polyolefin foam with a floorprotecting surface by providing a permanently applied covering layer made of a combination of thermoplastic plastic film, heatable in a high-frequency electrical field by dielectric heating, with a cross-linked polyolefin foam layer, which itself is not heatable by high frequency. This combination of the different materials according to the invention produces a floor mat with a wear-resistant surface that is suitable as a floor protector and that makes optimum use of the properties of the different materials. Using a thermoplastic plastic film which is dielectrically heatable in a high-frequency electric field, makes it possible to produce in an indirect fashion, by high-frequency heating, a permanent bonding of the floor-protecting surface layer with the floor mat. Preferably, films made of plastic with a dielectric constant of 2.5 to 6 and a dielectric loss factor less than 1.5 X 10-3, especially polyvinyl chloride or soft polyvinylchloride, ABS polymers, ethylene copolymers, ethylene copolymers, or polyamides, are used.
The basic floor mat, i.e. the base portion of the total mat construction, preferably consists of a chemically cross-linked polyethylene foam sheet, made, for example, by the method described in U.S. Pat. No. 3,651,183 preferably shaped under the influence of heat and pressure to the form, i.e. to the contour, of the interior of the
motor vehicle to be lined. If will be understood that the floor mat base may be flat or be shaped to have the contoured configuration which will mate with the floor interior of the motor vehilcle prior to application of the
5 floor protective surface layer. Generally the base is shaped after application of the protective surface layer to selected surface portions or areas. If the floor mat is made in one layer from a chemically cross-linked polyethylene sheet, a foam with a density of 100 to 150
10 kg/m3 with a thickness of 5 to 10 mm is preferably employed. This foam meets both the requirements for insulating properties and the abrasion resistance of the surface outside the floor area subjected to high wear. In addition, it is advantageous, in order to reduce the total
15 weight of the floor mat and also for economic considerations, to make the base floor mat out of two sheets of chemically cross-linked polyethylene foam, joined flush with one another, the sheets being laminated together, whereby the polyethylene foam sheet forming the side
20 exposed to wear has a density of 150 to 200 kg/m3 and a thickness of 2 to 5 mm, while the polyethylene sheet that forms the back has a density of 30 to 70 kg/m3 and is 4 to 10 mm thick. The polyethylene foam with the higher density in
25 creases the abrasion resistance and wear resistance of the side exposed to wear, while the polyethylene foam sheet with the lower density has a sufficient cushioning and insulating effect on the lining of the interior of the motor vehicle.
30 An important inventive idea for the floor mat is the use of a floor-protecting layer made of a laminate, whereby the side of the floor-protecting layer to be bonded to the upper exposed surface of the floor mat is formed by a layer of the same polyolefin foam as the
35 floor mat, which may have a different density. This permits the production of a homogeneous connection by melt welding; between the base floor mat and the floor-protecting layer, caused by the dielectric heating of the thermoplastic film of the protecting cover layer.
40 This connection reliably prevents the floor-protecting layer from coming loose from the floor mat during use. As far, as plastic film and the polyolefin foam layer cannot be bonded directly together by heat welding, the invention provides another embodiment for this bond
According to another embodiment of the invention, the plastic film and the polyolefin foam layer which form the floor-protecting surface layer are bonded together by an adhesion promoter which is cross-linkable
50 under the influence of heat. A preferred material combination provides for the use of a soft PVC film for the outer floor-protecting surface, which is flame-laminated with a chemically cross-linked polyethylene foam sheet by using an acrylic resin containing a hydroxyl group
55 and an isocyanate-based hardener. Manufacture of a laminate of this kind is described, for example, in German Offenlegungsschrift No. 2,707,727 and U.S. patent application Ser. No. 882,904, filed Mar. 2, 1978, now U.S. Pat. No. 4,259,408, while according to the present
60 invention this laminate can be applied to the desired floor mat as the floor-protecting surface, and worked.
Preferably, according to the invention, the polyolefin foam layer in the floor-protecting surface layer has a density of 70 to 100 kg/m3 and a layer thickness of 2 to
65 5 mm.
In another embodiment of the invention, a latticeshaped or coarse-mesh reinforcing layer, especially a layer of fiberglass or polyester fibers, is provided be