GB1567632A - Apparatus including tape with thermoplastic adhesive for installing carpeting - Google Patents

Description

(54) APPARATUS INCLUDING TAPE WITH THERMOPLASTIC ADHESIVE FOR INSTALLING CARPETING (71) We, DECO COATINGS CORPORAtion organised and existing under the laws of the State of Uennsylvania of P.O. Box 15072, Pittsburg, Pennsylvania, 15237, United States of America, do hereby declare the invention, for which we pray that -a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an improved apparatus including thermoplastic adheive tape for seaming together abutted edges of a covering such as carpet as well as for adhering covering material to a support surface. The present invention specifically provides apparatus including tape having a layer of hot-melt adhesive carried by a metal strip that is used inter alia to heat the adhesive to a bonding temperature by resistance heating produced by passing an electric current from a power supply along a selected length of the metal strip.

Hot-melt adhesive tape is currently used in the carpet industry to seam abutting edges of two pieces of carpeting together.

The adhesive tape consists of a kraft paper backing with a film of hot-melt adhesive to secure a fiberglass reinforcing strip to the kraft paper backing. A continuous pattern, sometimes in the form of parallel beads, is deposited along the upper surface of the reinforcing fiberglass strip. The adhesive is remelted just prior to the time when it is brought into contact with the adjacent marginal zones at the backs of the two carpet pieces for seaming them together. This is accomplished by progressively moving an electric iron or directing hot air from a blower along the tape to melt the adhesive, and then progressively positioning the carpet edges in an abutting relation. The marginal zones along the seam line at the face of the carpet are pressed onto the tape so that when the melted adhesive resolidifies, it will unite the pieces of carpeting at their back surfaces. This use of an electric iron or hot-air blower is hazardous and awkward. Moreover, the seaming operations require great skill by the installer because he must know at what rate the electric iron or blower should be moved along the tape in order to heat the hot-melt adhesive to a sufficient temperature which will insure its full use as an adhesive to form a bond. The bond must be of high integrity in order to assure the successful use of the tape in joining the pieces of carpeting together.

Heating the adhesive on the tape is very critical and the installer must take into consideration not only the available heat supply by the iron or blower but also the ambient temperature in the room and the temperature of the tape itself. The use of an iron to heat the hot-melt adhesive is a cumbersome operation. Typically, the iron must be inserted between the two pieces of carpeting and into contact with the ad hesive on the tape. The iron is then moved forwardly along the tape for a distance of approximately 2 to 3 feet. This distance is usually determined by the installer's skill to predict the period of time at which the adhesive will remain at an open temperature for bonding upon cooling. The carpet installer must then retrace his path back along the heated seaming tape and then abut the carpet pieces together while press ing them against the tape as he returns The installer is severely restricted as to the speed at which he can perform these operations because if too many feet of adhesive have been heated to a bonding temperature, then the adhesive will solidify before he can complete the abutted positioning of the carpet edges. During these operations there is the potential danger of burning the carpet due to an accidental misplace ment of the iron as well as burning the carpet at the seam line between the pieces of carpeting. Also, the installer may incur severe burns by accidental contact with the iron, particularly in light of his required quick movements to perform the carpet seaming operations. After the adhesive has cooled, it is practically impossible to adjust or reposition the carpet should this be necessary or desirable.

It is an aim of the present invention to provide an apparatus including an improved form of thermoplastic adhesive tape wherein a layer of hot-melt adhesive is deposited upon at least one side of a metallic strip substrate employed to generate therein a sufficient quantity of heat which will conductively heat the layer of hotmelt adhesive to a desired elevated temperature incident to the formation of a bonded connection.

According to the present invention there is provided an apparatus for seaming together abutting edges of carpeting at the back surface which faces toward a support surface therefor, the apparatus comprising, a layer of thermoplastic adhesive of the type which forms a bond upon cooling down to at least an ambient temperature after heating to an elevated temperature, an elongated metallic strip substrate carrying the layer of thermoplastic adhesive along one face surface thereof, the layer of adhesive being spaced inwardly from the two longitudinal edges of the substrate in a manner to expose the marginal edges thereof such that the exposed marginal edges receive heated adhesive when displaced as an incident to the carpet being urged at its abuting edges into contact with the adhesive at only one side of the substrate, and electrical power supply means including electrical leads connected to the metallic strip substrate in a manner to pass a resistive heating current along the length of the metallic strip lying between the leads for heating the thermoplastic adhesive carried thereby to a temperature at which it becomes plastic.

An embodiment of the apparatus according to the invention will now be described, by way of example, with referenc to the accompanying drawing, in which: Figure 1 is a partial plan view with broken-away portions to illustrate component parts of the apparatus according to the present invention for seaming together two pieces of carpeting; and Figure 2 is a cross-sectional view taken along line II-II of Figure 1.

The apparatus illustrated in Figs. 1 and 2 comprises a thermoplastic adhesive tape adapted to seam together abutting edges of two pieces of carpeting at the back surface thereof which faces toward a support surface provided by a floor which, in some instances, is covered by a resilient padding.

It is preferred to construct this tape in a manner such that it can be handled and transported in the form of a roll of tape.

Each roll will preferably include a length of tape of 15 feet or some multiple of this length for maximum compatibility with the standard widths of carpeting presently available in the industry. The length of tape which is removed from the roll will be selected so that it will extend along the full length of abutted edges of carpeting to be seamed together.

This tape includes a metallic strip substrate 60 that is preferably in the form of a strip of aluminium foil, e.g., .003 inch thick and about 3 inches wide. While different types of aluminium foil may be used, one particularly useful type is a wrought aluminium alloy having a designation No. 1145 by the Aluminum Association, Inc. This aluminium alloy has a minimum of 99.45% aluminium and 0.55% combined silicon and iron, 0.05% copper and 0.05% manganese. This alloy is an electrical conductor grade with a density of 0.098 lb/in3, a specific gravity of 2.71 and an average coefficient of thermal expansion of 13.1x10-6 at 68"F to 212"F.

The physical properties at an 0 temper include a thermal conductivity of 1540 BTU/ in/ft2/0F/hr. at 77"F, an electrical conductivity at 68"F of 59% at an equal volume of international annealed copper standard, and an electrical resistivity at 68"F of 2.9 ohm-centimeters.

A reinforcing strip of scrim 61, which may be coated and made of fiberglass, is adhered to one face surface of the substrate by a thin film or layer 62 of thermoplastic adhesive of a type to be hereinafter more fully described. A layer 63 of thermoplastic adhesive overlies the top surface of the scrim and preferably also its side edges. The total thickness of the thermoplastic adhesive is preferably within the range of 6 to 14 mils. Layers 62 and 63 of thermoplastic adhesive are preferably formed at the same time by the hot application of a layer of adhesive onto scrim located upon the face of the substrate.

While different forms of strip-like reinforcing material may be employed, it is preferred to use scrim designated as White Weave Set No. 857, Style 1658 and sold by J. P. Stevens & Co., Inc. Such scrim has a thickness of .004 inch and 1.65 ounces per square yard. This scrim has a plain weave, a 20x 10 yarn count per square inch with a tensile strength of 80 X 70 lb/in2. When the substrate 60 is 3 inches wide, then the scrim is centrally located thereon and is preferably 2 inches wide.

The layer of thermoplastic adhesive is 2-1/4 inches wide so that about a 3/8 inch margin of exposed substrate extends along each side of the layer of thermoplastic adhesive. The exposed marginal edges of the substrate are utilized to receive heated thermoplastic adhesive when displaced from the layers 62 and 63 by the force applied to overlying pieces of carpeting or similar types of covering at each side of a seam line incident to bonding such pieces together without bonding the tape and/or carpet to the floor. The exposed marginal edges of the metallic strip substrate 60 are utilized as contact areas for the temporary attachment of the clips 20A and 21A connected by lines 20 and 21, respectively, to a low-voltage power supply 22 at the opposite ends of a selected length of tape for resistance heating thereof. The tape of the present invention enables the installation of carpeting at significantly lower working temperatures of the thermoplastic adhesive.

This is particularly important in regard to the installation of carpeting or a similar type of covering which is damaged by the exposure to temperatures as low as 250"F, for example. The thermoplastic adhesive can be readily compounded and designed to exhibit a melting temperature as low as 200"F, if desired, but a more typical melting temperature of 350"F is preferred when the particular carpeting or covering can withstand such a temperature for the relatively short period of time required to form a bond. The thermoplastic adhesive must be dry and without tack at a normal ambient room temperature so as to avoid creep to the bonded joints.

The present invention greatly improves the method and tape used for forming a bonded joint incident to the installation of a covering. The installer can quickly position a desired length of adhesive tape at the seam line below pieces of carpeting as well as quickly position the adhesive tape in the desired relation with the outer edge of the carpet even when a nail strip or similar type of anchoring device is used.

After the adhesive tape is positioned, the resistance heating of the thermoplastic adhesive is carried out throughout the entire selected length of the adhesive strip.

This frees the operator to assure optimum results without the necessity of manually bringing the carpeting into the final desired relationship. Long continued integrity of the bonded connection can be assured by applying pressure to the top surface of the covering after the thermoplastic ad hesive has attained a bonding temperature.

The adhesive layers 62 and 63 consist of adhesive material that is strong, ages well and will not damage the floor surface. The adhesive material should be resistant to cleaning materials. The preferred adhesive is a hot-melt type of thermoplastic adhesive. The adhesive is of high viscosity and essentially includes an ethylene-vinyl acetate copolymer modified with paraffin wax, an antioxidant and a plasticizing resin. The softening point of this adhesive is 65"C and it has a cracking point below 0 C. The adhesive has a viscosity of 30,000 centipoises at 250"F with a No. 4 spindle on a Brookfield viscosity meter at 1-1/2 revolutions per minute and a specific gravific gravity of .987 gram per cubic centimeter at 25"C. Such an adhesive is sold by Gateway Paint and Chemical Company of Pittsburgh, Pennsylvania. Another form of hot-melt type of thermoplastic adhesive sold by Gateway Paint and Chemical Company bears designation No.

P 722. This thermoplastic adhesive has a viscosity of 5800 centipoisse at 3000F and 2100 centipoises at 350"F. The adhesive will peel and shear at 1200F and its softening point is 155"F.

After the selected length of adhesive tape is located to extend along the pad or floor, the two pieces of carpeting are brought into an abutting relation defining a seam line which is oriented in regard to the adhesive strip so that the two marginal zones at either side of the seam line at the backs of the carpet overlie the thermoplastic adhesive. The thermoplastic adhesive layer is deposited as a continuous strip-like layer. The tape is oriented so that the seam line extends approximately midway between the longitudinal edges of the tape. As indicated previously, it is intended that a length of tape is selected so that it extends along the entire length of the seam to be formed between two pieces of carpeting. Thus, for example, when two 15-foot wide pieces of carpeting are to be joined together, then the length of tape selected would be 15 feet long. After the carpet and tape have been located as just described, then a lead wire 20 is connected by way of the alligator clip 20A into electrical contact with the metal strip substrate 60 at one end of the tape and a lead wire 21 is connected by an alligator clip 21A to the metal strip substrate at the other end of the tape. The lead wires 20 and 21 are, in turn, connected to the output terminals of the power supply 22 including a step-down transformer. The power supply is of a conventional well-known construction. It receives, for example, a 120 volt alternating current to provide an output of 16 volts in the leads 20 and 21 at a maxi mum current of 100 amperes, for example.

Moreover, the rating of the power supply should be of the order of 1-1/2 kilovolt amperes and includes a current limiting adjustment control whereby an operator may control the resistance heating of the wire mesh and thereby the layer of adhesive for a controlled open time in a dependent relation to the actual length of the thermoplastic adhesive tape.

The period of time during which the thermoplastic adhesive is nonfunctional is referred to as the " open time". The open time is controlled according to the present invention and may be extended by the agency of electrical heating. The adhesive can be repeatedly reheated to facilitate adjusting the carpet as desired or necessary.

The resistance heating is then discontinued to allow the adhesive to cool and form a bonded joint between the adhesive tape and the floor.

WHAT WE CLAIM IS: - 1. Apparatus for seaming together abutting edges of carpeting at the back surface which faces toward a support surface therefore, the apparatus comprising: a layer of thermoplastic adhesive of the type which forms a bond upon cooling down to at least an ambient temperature after heating to an elevated temperature, an elongated metallic strip substrate carrying the layer of thermoplastic adhesive along one face surface thereof, the layer of adhesive being spaced inwardly from the two longitudinal edges of the substrate in a manner to expose the marginal edges thereof such that the exposed marginal edges receive heated adhesive when displaced as an incident to the carpet being urged at its abutting edges into contact with thet adhesive at only one side of the substrate, and electrical power supply. means including electrical leads connected to the metallic strip substrate in a manner to pass a resistive heating current along the length of the metallic strip lying between the leads for heating the thermoplastic adhesive carried thereby to a temperature at which it becomes plastic.

2. An apparatus according to claim 1 further including reinforcing means for the layer of thermoplastic adhesive.

3. An apparatus according to claim 1 wherein the metallic strip substrate is a strip of aluminium foil.

4. An apparatus according to claim 2 wherein the layer of thermoplastic adhesive encapsulates the reinforcing means.

5. An apparatus according to claim 4 wherein the reinforcing means has a striplike form the width of which is essentially less than the width of the layer of thermoplastic adhesive on the metallic strip.

6. An apparatus according to claim 4 wherein the reinforcing means comprises a strip of scrim.

7. An apparatus according to any preceding claim wherein the metallic strip has an electrical resistivity of 2.9 ohm-centimeters at 68"F.

8. An apparatus according to any preceding claim further comprising clip means attached to each of the electrical leads for passing the resistive heating current to the metallic strip.

9. An apparatus for seaming together abutting edges of carpeting substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. mesh and thereby the layer of adhesive for a controlled open time in a dependent relation to the actual length of the thermoplastic adhesive tape. The period of time during which the thermoplastic adhesive is nonfunctional is referred to as the " open time". The open time is controlled according to the present invention and may be extended by the agency of electrical heating. The adhesive can be repeatedly reheated to facilitate adjusting the carpet as desired or necessary. The resistance heating is then discontinued to allow the adhesive to cool and form a bonded joint between the adhesive tape and the floor. WHAT WE CLAIM IS: -

1. Apparatus for seaming together abutting edges of carpeting at the back surface which faces toward a support surface therefore, the apparatus comprising: a layer of thermoplastic adhesive of the type which forms a bond upon cooling down to at least an ambient temperature after heating to an elevated temperature, an elongated metallic strip substrate carrying the layer of thermoplastic adhesive along one face surface thereof, the layer of adhesive being spaced inwardly from the two longitudinal edges of the substrate in a manner to expose the marginal edges thereof such that the exposed marginal edges receive heated adhesive when displaced as an incident to the carpet being urged at its abutting edges into contact with thet adhesive at only one side of the substrate, and electrical power supply. means including electrical leads connected to the metallic strip substrate in a manner to pass a resistive heating current along the length of the metallic strip lying between the leads for heating the thermoplastic adhesive carried thereby to a temperature at which it becomes plastic.

2. An apparatus according to claim 1 further including reinforcing means for the layer of thermoplastic adhesive.

3. An apparatus according to claim 1 wherein the metallic strip substrate is a strip of aluminium foil.

4. An apparatus according to claim 2 wherein the layer of thermoplastic adhesive encapsulates the reinforcing means.

5. An apparatus according to claim 4 wherein the reinforcing means has a striplike form the width of which is essentially less than the width of the layer of thermoplastic adhesive on the metallic strip.

6. An apparatus according to claim 4 wherein the reinforcing means comprises a strip of scrim.

7. An apparatus according to any preceding claim wherein the metallic strip has an electrical resistivity of 2.9 ohm-centimeters at 68"F.

8. An apparatus according to any preceding claim further comprising clip means attached to each of the electrical leads for passing the resistive heating current to the metallic strip.

9. An apparatus for seaming together abutting edges of carpeting substantially as herein described with reference to the accompanying drawings.