JP4246771B2 - Flame retardant fastener - Google Patents

Description

  The present invention relates to a flame retardant fastener, and more particularly to a flame retardant headed fastener with a pressure sensitive adhesive on its back surface.

  Hook and loop fasteners that pass certain flame retardant tests include those with a flat back and pressure sensitive adhesives. However, hook and loop fasteners are not suitable for industrial fixing applications requiring high strength. For certain electronics, aerospace, rail transport and automotive applications, high strength industrial quality fasteners with suitable flame retardant properties are required.

  Headed protrusion fasteners are suitable for many high-strength fixed applications, but have been limited by the lack of flame retardancy. For example, currently available headed fastener fasteners are marketed under the trade name Dual Lock from Minnesota Mining and Manufacturing Company of St. Paul, Minnesota. Regulation (F.A.R.) 25.853 (a) (1) (iv) and (a) (1) (v) conforms to the horizontal combustion test specified in F. A.R. A. R. It does not conform to the vertical combustion test. F. As required by the aerospace industry. A. R. The vertical burn test defined in 25.853 (a) (1) (i) and (a) (1) (ii) is currently the most stringent flame retardant standard for such fasteners.

  Fillers added to the material to improve flame retardancy often change the properties of the material used in the headed fastener. In particular, pressure sensitive adhesives require 5-30% filler by weight to achieve flame retardancy. More than about 10% filler can adversely affect skin adhesion and lose tackiness depending on particle size and filler chemistry. The filler can even prevent curing. For example, generally 30% filler is required to obtain flame retardancy with an acrylic adhesive. However, the filler not only reduces the adhesion and tackiness of the epidermis, but also interferes with the UV curing of the acrylic adhesive.

Some high performance fasteners have a dynamic tensile detachment force in the range of 207 to 414 kPa (30-60 lbs./in ² ) over a cycle life of 1000 engagements. Therefore, the adhesive utilized for fastener locking must be able to withstand significant peel and tensile release forces over an extended period of time. The filler may reduce the overall strength of the material.

  The processing parameters associated with the production of headed fasteners may change due to the change in melting characteristics of the material due to the filler. For example, in one embodiment, the head of the headed fastener fastener is formed by thermal deformation. Filler heat change may be delayed or hindered. Extensive research has been conducted on forming optimally shaped heads using polymers containing less than 2% by weight of fillers such as pigment concentrates, UV stabilizers, and anti-aging agents. Ultimately, the addition of fillers and reduced production rates increase the overall cost of the product.

  It is an object of the present invention to provide a flame retardant headed fastener with a pressure-sensitive adhesive on the back surface, which can solve the above-mentioned problems of conventional fasteners. It is.

  The present invention relates to a flame retardant headed fastener with a pressure sensitive adhesive on the back side.

  The flame retardant fastener is suitable for releasably engaging the second fastener. The backing layer of the fastener is made from a flame retardant polymeric material having an exposed adhesive surface and a support surface. The plurality of flexible elastic protrusions protrude substantially perpendicular to the bonding surface. The terminal protrusion has a swollen head at its end. The upper surface of the swollen head faces the terminal protrusion, and the engagement surface faces the adhesive surface. The head is positioned so as to be removably engageable with the second fastener along various portions of the backing layer. A non-flame retardant pressure sensitive adhesive is applied to the support surface.

  In one embodiment, the non-flame retardant pressure sensitive adhesive is a foam layer of an acrylic foam pressure sensitive adhesive. Alternatively, the non-flame retardant foam layer is provided between the support surface and the pressure sensitive adhesive. The non-flame retardant foam layer is preferably selected from the group consisting of acrylic foam, urethane foam, polyethylene foam, neoprene, and silicone.

  The thickness of the foam layer is preferably thinner than the thickness of the backing layer. The foam layer is preferably less bulky than the backing layer. In one embodiment, the foam layer preferably has a maximum thickness of about 0.035 inches. Alternatively, the maximum thickness of the foam layer is preferably about 3.05 mm (0.120 inch).

  The minimum vertical peel strength of the non-flame retardant pressure sensitive adhesive or adhesive / foam system is preferably 1428.8 grams / cm (8 lbs / inch), more preferably 2857.6 grams / cm (16 lbs / inch). The stronger the peel strength of the adhesive, the longer the cycle life of the fastener when bonded to the support. The pressure sensitive adhesive is substantially coated with a release liner. The thickness of the backing layer may be in the range of 0.051 mm to 3.05 mm (0.002 to 0.120 inch), preferably 0.254 mm to 1.52 mm (0.010 to 0.060 inch). ), And most preferably in the range of 0.51 mm to 1.02 mm (0.020 to 0.040 inch).

  In one embodiment, the protrusion is a generally U-shaped monofilament made of a non-flame retardant polymer material oriented in the longitudinal direction and embedded in the adhesive surface. The flame retardant polymeric material is preferably selected from the group consisting of polyolefin, polyamide, polyurethane, polypropylene, and polyethylene.

  Fastener A. R. It is preferable to satisfy the requirements of the vertical flammability test in the state where it is not attached to the substrate in 25.853 (a) (1) (i). After being exposed to the flame for 60 seconds, the burn length of the vertically oriented portion of the fastener should be less than 152.4 mm (6 inches) in 15 seconds. After exposure to the flame for 60 seconds, the fasteners burn for less than 15 seconds. The drops may not continue to burn for an average of more than about 3 seconds after falling.

  In one embodiment, the second fastener comprises a headed fastener fastener. The heads are arranged in a pattern such as a plurality of rows, an irregular configuration, or a sinusoidal pattern.

  The following are mentioned as a preferable aspect of this invention.

The present invention comprises a backing layer of a flame retardant polymeric material having an exposed adhesive surface and a support surface;
A plurality of flexible elastic protrusions protruding substantially perpendicular to the bonding surface, the protrusions being made of a non-flame retardant polymer material embedded in the bonding surface, The head is at the end of the protrusion, the bulging head has a cam-shaped surface facing the protrusion and an engagement surface facing the adhesive surface, and the head is adjacent to the protrusion. Flexible elastic protrusions disposed so as to be movable between,
Comprising a non-flame retardant pressure sensitive adhesive applied to the support surface;
And further comprising a non-flame retardant foam layer sandwiched between the support surface and the pressure sensitive adhesive.
A flame retardant fastener configured to detachably engage a second fastener,
The burn length of the fastener's vertical orientation in 15 seconds after approximately 60 seconds of exposure to the flame is less than 152.4 mm (6 inches), and the fastener burns in less than 15 seconds after being applied to the flame for 60 seconds. Furthermore, after 60 seconds of exposure to the flame, the drops will not continue to burn for an average of more than 3 seconds,
And the non-flame retardant pressure sensitive adhesive comprises a foam layer of acrylic foam pressure sensitive adhesive,
Further, the bulk of the foam layer is less than the bulk of the backing layer,
Furthermore, the non-flame retardant foam layer is selected from the group consisting of acrylic resin foam, urethane foam, polyethylene foam, neoprene, and silicone foam,
The flame retardant polymer material is selected from the group consisting of polyolefin, polyamide, polyurethane, polypropylene, and polyethylene.
Related to flame retardant fasteners.

  FIGS. 1 and 2 show flame retardant fasteners 10, 12, and 14 having a plurality of headed fastener fastener members 21 projecting from a flame retardant backing layer 22. The backing layer 22 includes one or more types of flame retardant materials 22a. The headed protrusion fastener member 21 is composed of a plurality of supple and elastic substantially U-shaped single fibers embedded and bonded or fused in a flame-retardant backing layer 22. The single fiber 24 has a projecting portion 26 that protrudes substantially perpendicular to the adhesive surface 28 of the flame-retardant backing layer 22. At the end of the protrusion 26 is a head 30. The head 30 has a cam-shaped surface 38 that faces the protrusion 26 and an engagement surface 40 that faces the adhesive surface 28 (see FIG. 2).

  The bit portions 36 of the group of single fibers 24 are arranged side by side so as to form a series of substantially parallel rows, and each row of single fibers has a protruding portion 26 and a head portion 30 aligned in a straight line. There are two rows with Here, it should be understood that the single fibers 24 may be randomly arranged on the flame-retardant backing layer 22 or may be arranged in a pattern such as a sinusoidal pattern. The adjacent projecting portions 26 of the U-shaped single fibers 24 adjacent to the projecting portions 26 of the respective U-shaped single fibers 24 are substantially the same as the head portions 30 of the other single fibers 24 of the fastener 10. It is preferable that the protrusions 26 are arranged apart from each other so that the protrusions 26 can be arranged between them without spreading. U-shaped single fibers are made from a non-flame retardant polymer material oriented in the longitudinal direction. It is preferable that the length of the protruding portion of each single fiber 24 is the same.

  The foam layer 32 may be adhered to the support surface facing the adhesive surface 28 of the flame retardant backing layer 22 with an adhesive. The opposite side of the foam layer 32 comprises a tacky pressure sensitive adhesive 20 covered with a peelable silicone release liner 35. The thickness of the pressure sensitive adhesive is generally in the range of 0.025 to 0.635 mm (0.001 to 0.025 inches). The thickness of the foam layer 32 is preferably 0.051 to 3.05 mm (0.002 to 0.120 inch), more preferably 0.051 to 1.52 mm (0.002 to 0.060 inch), Most preferably, it is 0.051-0.889 mm (0.002-0.035 inch). In one embodiment without the foam layer 32, the pressure sensitive adhesive 20 is applied to the support surface of the flame retardant backing layer 22. It is preferable to apply a primer to the support surface before applying a specific intermediate pressure adhesive such as an acrylic adhesive. In yet another alternative embodiment, the foam layer 32 may be made from a thick adhesive, such as an acrylic adhesive, as described below. In these embodiments using an acrylic adhesive, it is preferable to laminate a primer layer on the support surface before applying the acrylic adhesive.

  FIG. 2 is a sectional view of the two flame retardant fasteners 12 and 14 of FIG. The fasteners 12 and 14 are bonded to the substrates 16 and 18 by a pressure sensitive adhesive 20, respectively. The cam-shaped surface 38 of the head 30 serves to deflect the protrusion 26 as the heads 30 move so as to be engaged with each other. The two-dimensional engagement surface 40 extends radially outward from the protrusion 26 and engages with the engagement surface 40 of one or more heads of the opposing fastener portion 12 or 14. The engagement surface 40 holds the head 30 in an engaged state until a predetermined force is applied to separate the fastener portions 12 and 14.

  The heads 30 of the adjacent projecting parts 26 have a diameter larger than that of the heads 30 of the other fastener parts 12 or 14 when the heads 30 are separated by elastic deflection of the projecting parts 26. Is also placed at a small distance. As generally described in US Pat. No. 4,216,257 (Schams et al.), Which replaces the description herein by reference, it corresponds to the force trying to separate the fastener portions 12 and 14. The foam layer 32 bends the flame retardant backing layer 22 to correct the small difference in length between the protrusions 26, and most of the engaging surfaces 40 of the head 30 are simultaneously engaged to fasten the fastener. The holding force of 10 is maximized.

  The flame retardant fastener 10 is made by any suitable method, such as the method disclosed in US Pat. No. 4,290,174 (Kalleberg), which replaces the description herein with reference to the literature. Also good. An injection molding process for making headed fasteners is disclosed in US Pat. No. 5,077,870 (Melby et al.), Which is incorporated herein by reference.

  Alternatively, the backing layer 22 and the headed protrusion 21 may be produced by injection molding using a leg mold that can be destructively removed. Examples of injection molding processes that utilize destructively removable leg molds are all described in US Pat. No. 5,242,646 (Toroshigo et al.), Which is hereby incorporated by reference. No. 5,398,387 (Toroshigo et al.). In this regard, the leg mold that can be destructively removed is used as a core of a metal mold, for example, a mold that can be detached by ultrasonic vibration, melting, dissolution with water or solvent, or powdering. It is a general term that refers to. In this case, the destructively detachable leg mold is used as a mold for one or both of the cut and / or groove formed on the leg and head of the headed head, and the base and head of the headed head. It is used after integrally forming a leg portion provided with a portion. The destructively removable leg mold may be detached by suitable mechanical or chemical methods. Alternatively, a destructively removable leg mold may be used only as a leg mold and one or both of the cut-out and the groove may be formed from a suitable metal mold. In the case of molded fasteners, the backing layer, legs, and head may be made of a flame retardant polymer material.

  The preferred foam layer 32 comprises a non-flame retardant pressure sensitive foam or pressure sensitive adhesive system. Alternatively, the foam layer 32 may be a plurality of layers obtained by bonding a foam and an adhesive. The foam layer 32 can be applied by hot melt coating, coating and UV curing, direct lamination, or various other techniques well known in the art. The density of the non-flame retardant foam layer 32 is preferably at least 0.03 grams / cubic centimeter, more preferably at least 0.096 to 1.01 grams / cubic centimeter (6-63 pounds / cubic foot). The thickness of the foam layer 32 is at least 0.05 mm (0.002 inches). Two types of non-flammable closed cell pressure sensitive acrylic foams known to be suitable for use with the flame retardant fastener 10 are Scotch brand VHB tape, product number 4905 and product number Y-. It is sold under the trade name 4251 Scotch-Mount brand acrylic foam tape, both of which can be purchased from Minnesota Mining and Manufacturing, St. Paul, Minnesota. The 4905 acrylic foam has a thickness of about 0.5 mm (0.020 inches) and a density of about 997 kilograms / cubic meter. One surface of Y-4251 is further laminated with a pressure sensitive adhesive of 0.05 mm (0.002 inch), with a total thickness of about 0.94 mm (0.037 inch), reported. The density is between 515 kilograms / cubic meter and 675 kilograms / cubic meter.

  When subjected to the vertical skin adhesion test, the Y-4251 acrylic resin foam adhesive was 0.51 mm (0.020 inch) thick primed width 25.4 mm (1 inch) × length 203 mm (8 Inch) When applied to a section of polypropylene substrate and attached to a stainless steel panel at room temperature with a holding time of 1-2 hours, the adhesive is at least 1428.8 grams / cm (8 lbs./inch) , And typically 13-16 lbs./inch (2321.8-2857.6 grams / cm).

  The flame retardant backing layer 22 is preferably a uniform layer of non-fibrous flexible polymer material containing a flame retardant material 22a. Suitable polymeric materials include polyethylene, polypropylene, polyamide, or polyester resin. The impact-resistant polypropylene resin is one of the more preferable materials because of its heat resistance, mechanical strength, and workability. The bending module having the bending resistance of the material can be arbitrarily changed or changed by adding a plasticizer, a toughening agent, or the like. The polyolefin resin is generally a flame retardant inorganic component such as alumina trihydrate, antimony trioxide, iron oxide, magnesium carbonate, magnesium hydroxide, red phosphorus, silicon, zinc borate, or the like. It can be made flame retardant by adding components, or flame retardant organics such as brominated aromatic compounds, brominated or chlorinated aliphatics, phosphate esters, halogenated phosphite char formers, and phosphorus compounds.

  Various commercially available VO class flame retardant polyolefin resins are suitable for use as the backing layer 22 of the present invention. The V-O grade material satisfies the 20 mm vertical combustion test 94V-0 of Underwriters Laboratories (UL), the contents of which are incorporated herein by reference. Depending on the application, UL 20 mm vertical flame test 94V-1 or 94V-2 grade polymers may have sufficient flame retardancy. For example, if the foam layer is sufficiently thin, 94V-1 or 94V-2 class polymers can be used as described in F.F. A. R. May satisfy 25.853.

  Flame retardant polypropylene sheet materials suitable for use as the backing layer of the present invention include Formex-20, Formex-40, and improved impact resistance Formex GK, available from ITW Fastex, Des Plaines, Illinois. -10, Formex GK-17, Formex GK-30, Formex GK-40, and Formex GK-62. Another flame retardant polypropylene resin suitable for use as the flame retardant backing layer 22 is commercially available from Monmouth Plastic Company of Freehold, NJ under the trade name Type PP301. The material properties presented by the manufacturer are summarized in Tables 1 and 2 below.

The flame retardant fastener of the present invention is suitable for applications in electronics, aerospace, rail transport, and automobiles. Although there are various criteria for assessing flame retardancy, Federal Aviation Regulations is currently the most stringent test. Accordingly, the flame retardant fasteners of the present invention are F.S. A. R. Evaluation was performed based on paragraph (a) (1) (i) of 25.853.
F. A. R. Test criteria and test method to show conformity to 25.853 (July 1990) Subparagraphs (a) (1) (i), which are fastener test criteria for vertical combustion tests, are internal vehicles occupied by crew or passengers. It is about the room. The present invention relates to materials used for the structure of internal ceiling panels, internal wall panels, partition walls, kitchen structures, large cabinet walls, structural flooring, and loading chambers. Subparagraph (a) (1) (ii) includes seat cushions, padding, decorative or non-decorative coated fabrics, leather, trays, kitchen fixtures, electrical ducts, insulation and soundproofing air ducts, joints and ends. It relates to coating. Materials used in these applications must exhibit self-extinguishing properties when tested vertically according to the procedures of §25.853 (a) (1) (i) and (a) (1) (ii).

  The specimens must be adjusted to 21.1 ° C ± 2.8 ° C (70 ± 5 ° F) at 50% ± 5% relative humidity until the moisture balance is 24 hours. Each specimen must be in a conditioned environment until exposed to flame. The test piece must be mounted vertically on the metal frame so that the two long edges and the top edge are securely held in a state where they are not attached to or supported by the substrate. If the actual size used on the aircraft is more than 50.8mm (2 inches) wide and 304.8mm (12 inches) long, the exposed area of the specimen should be at least 50.8mm (2 inches) wide and 304.8mm long Must be (12 inches). The burner flame edge must not be the finished or protective edge of the specimen, but must correspond to the natural cross section of the material to be attached to the aircraft. At least three specimens must be tested and the results averaged.

  Specimens must be addressed to a Bunsen or Chillyl burner equipped with a standard 9.53 mm (3/8 inch) inner diameter tube adjusted to emit a flame of 38.1 mm (1 to 1/2 inch) in height. Absent. The minimum flame temperature in the center of the flame measured with a calibrated thermocouple pyrometer must be 843.3 ° C (1550 ° F). The lower edge of the specimen shall be set 19.1 mm (3/4 inch) above the upper edge of the burner. The flame must strike the center line of the lower edge of the specimen. Burning time, burning length, and drop burning time (if any) must be recorded.

  Subparagraphs (a) (1) (i) require that the flame be removed after 60 seconds of exposure. The average burning length should not exceed 152.4 mm (6 inches) and the average burning time after removing the flame source should not exceed 15 seconds. Drops should not continue to burn for more than 3 seconds on average after falling. The combustion length is the distance from the edge of the test piece to the damage mark due to the thermal shock farthest from the edge. Damage marks include partially or completely burned parts, carbonized parts, and embrittled parts, but do not include smoke-smudged parts, contaminated parts, strained parts, discolored parts, and parts where the material has shrunk or melted due to heat.

  Subparagraphs (a), (1), and (ii) require that the flame be removed after 12 seconds. The average burning length should not exceed 3 inches and the average burning time after removing the flame source should not exceed 15 seconds. Drops should not continue to burn for an average of more than 5 seconds after falling.

  A series of samples were prepared to investigate whether the use of flame retardant materials in the backing layer, foam layer, and / or pressure sensitive adhesive. In the following examples, F.I. A. R. A combination of commercially available materials was tested according to the vertical combustion test of 25.853 (a) (1) (i). Product specifications are as published by the manufacturer. The monofilament used here was a non-flame retardant black polypropylene with a diameter of 0.38 mm (0.015 inch) commercially available from Shakespeare in Columbia, Southern California. F / R indicates a flame retardant material.

All of the foams of Example 1 are polyethylene foam with a density of 96 kgs / m ³ (6 lbs./ft ³ ), commercially available from Voltek, Lawrence, Mass., With a thickness of 0.787 mm ( 0.031 inch). 6EO foam is non-flame retardant and 6TS foam is flame retardant. Unless otherwise specified, a pressure sensitive adhesive with a thickness of 0.50 mm (0.002 inch) is applied to both sides of the foam. Samples 4-7 non-flame retardant backing layer is a 0.05 mm (0.020 inch) thick black polyolefin with a protrusion density of 39 / cm 2 (250 / sq. In). Sample 4-7 backing layer and headed protrusion, a standard detachable fastener under the product number SJ3440, trade name Dual Lock, commercially available from Minnesota Mining and Manufacturing Co., St. Paul, Minnesota . Samples 1 and 7 utilize a non-flame retardant acrylic adhesive identified as Scotch brand VHB tape, product number F-9460PC, available from Minnesota Mining and Manufacturing, Inc., St. Paul, Minnesota And produced. Samples 2, 3, 4, and 6 are H.P., St. Paul, Minnesota. B. Made using a rubber-based flame retardant adhesive, product number HL-2086, commercially available from Fuller.

  Sample 5 was produced using a non-flame retardant hot melt adhesive called Adhesive A. Adhesive A is a pressure sensitive adhesive made generally in accordance with US Pat. No. 5,453,319. The adhesive material is 19.8 wt% rubber Kraton 1118 commercially available from Shell Oil Company, Houston, Texas, and commercially available from Housemex, Inc., Houston, Texas. 20.8 wt% of the rubber Solprene 1205, 48.3 wt% of the resin Piccolite A135 available from Hercules, Inc. of Brunswick, Ga., Shell Oil Company of Houston, TX 10.1% by weight of the oil Shellflex 371 commercially available from) and commercially available from Ciba Geigy, Macintosh, Texas. 1.0% by weight of the anti-corridor Irganox 1076.

  In sample 6, since there is no foam, a flame-retardant (F / R) rubber base adhesive is applied directly to the support surface of the backing layer. Various combinations of flame retardant and non-flame retardant foams and pressure sensitive adhesives can be found in F.I. A. R. According to 25.853 (a) (1) (i). The results are summarized in Table 3 below.

  The flame retardant foam and non-flame retardant adhesive of Sample 1 failed the vertical burn test. Similarly, the flame retardant adhesive comprising the non-flame retardant foam of sample 2 and the flame retardant adhesive comprising the flame retardant foam of sample 3 also failed. The non-flame retardant backing in combination with the flame retardant foam and adhesive of sample 4 failed. Samples 5 and 7 made with non-flame retardant backing and flame retardant foam also failed.

Example 2
To confirm the effect of utilizing a flame retardant backing layer and various non-flame retardant foam layers, single fibers, and pressure sensitive adhesives, a series of samples were made. Many of the materials have already been identified in Example 1. The 4492 adhesive / foam system is a white polyethylene foam tape having a thickness of 0.25 mm, an acrylic adhesive layer having a thickness of about 0.8 mm and a density of about 96 kgs / m ³ (6 lbs./ft ³ ). And is commercially available from Minnesota Mining and Manufacturing, Inc., St. Paul, Minnesota. Product Number F-9473 PC's Scotch Brand VHB Tape is a 0.254 mm (0.010 inch) clear acrylic adhesive transfer tape from Minnesota Mining and Manufacturing Company, St. Paul, Minnesota It is commercially available.

  Adhesive B is a rubber-based pressure sensitive adhesive made generally in accordance with Example 17 of US Pat. No. 5,453,319.

US Pat. No. 4,290,174 uses flame retardant polypropylene with a thickness of 0.51 mm (0.020 inches) commercially available from ITW Fastex Co., Death Plain, Illinois under the product name Formex 20BK. A backing layer was made based on the process disclosed in (Kalleberg). Backing layer has a headed stems of 6.45 cm ² (1 square inch) 400 per. The second dimension of Samples 15-20 refers to a greater adhesive burn length than the backing layers of these samples. A summary of the test results is listed in Table 5 below.

  As is apparent from Table 4, F. using a flame retardant material only for the backing layer and a non-flame retardant material for the foam layer, adhesive layer, and monofilament. A. R. The vertical combustion test of 25.853 (a) (1) (i) can be satisfied.

  Example 3 relates to a series of tests to confirm the effect of backing thickness on flame retardancy. A series of backing / adhesive samples were made by laminating 0.94 mm (0.037 inch) white acrylic foam to flame retardant polypropylene of various thicknesses. The backing layer was formed with no protrusions. The acrylic resin foam tape is an acrylic resin foam tape commercially available from Minnesota Mining and Manufacturing Co., St. Paul, Minnesota under the product name Scotch Mount Brand Y-4251. The backing layer is an impact-resistant polypropylene sheet material available from ITW Fastex, Inc., Death Plain, Illinois, and the product names are Formex-31 natural color, Formex-40 natural color, Formex GK- 40 black. As described in Table 6 below, F.R. A. R. These samples were tested according to 25.853 (a) (1) (i).

  Burning droplets ignited the material that was already dripped. From Table 5, it can be seen that the thicker the flame retardant backing layer, the shorter the burning time of any non-flame retardant foam and adhesive.

Example 4
Example 4 relates to a series of tests to confirm the effect of backing thickness on flame retardancy. A series of backing / adhesive samples were made by laminating a 0.64 mm (0.0220 inch) thick clear acrylic resin foam to various thicknesses of flame retardant polypropylene. The backing layer was formed with no protrusions. The acrylic resin foam tape is commercially available from Minnesota Mining and Manufacturing, Inc. of St. Paul, Minnesota under the product name Scotch Mount Brand VHB Tape 4905. The backing layer is an impact modified polypropylene sheet material available from ITW Fastex, Inc., Death Plain, Illinois, with product names Formex-31 natural color, Formex-40 natural color, and Formex GK depending on thickness. -40 black. As described in Table 7 below, F.R. A. R. These samples were tested according to 25.853 (a) (1) (i).

  From Examples 3 and 4, it can be seen that flame retardancy improves with the thickness of the backing layer. The backing layer must have sufficient thickness and sufficient bulk to prevent non-flame retardant foam and adhesive burning. It can be seen that a flame retardant fastener can be produced by combining a flame retardant backing layer with a larger volume per unit area of the fastener than the non flame retardant foam and the adhesive.

Example 5
Using a method disclosed in U.S. Pat. No. 4,290,174 (Kalleberg), a headed protrusion fastener having 26.8 protrusions / cm ² (170 inches per square inch) is manufactured. did. The backing layer was composed of the above-mentioned Formex GK-30 black and was laminated with Scotch brand VHB tape of product number 4905. F. A. R. When tested according to 25.853 (a) (1) (i), the sample had a burn length of 105 mm (4.13 inches), a burn time of 0 seconds, and a drop burn time of 1 second. The sample passed the test.

  The foregoing has described the invention with reference to several embodiments. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the invention. Accordingly, the scope of the present invention is not limited to the structures described in the specification, but is limited to structures described by the wording of the claims and equivalents thereof.

FIG. 1 is a partial perspective view of a flame retardant fastener. FIG. 2 is a cross-sectional view of a state where two opposed portions of the flame-retardant fastener are engaged.

Claims (1)

A backing layer of a flame retardant polymeric material having an exposed adhesive surface and a support surface;
A plurality of flexible elastic protrusions protruding substantially perpendicular to the bonding surface, the protrusions being made of a non-flame retardant polymer material embedded in the bonding surface, The head is at the end of the protrusion, the bulging head has a cam-shaped surface facing the protrusion and an engagement surface facing the adhesive surface, and the head is adjacent to the protrusion. Flexible elastic protrusions disposed so as to be movable between,
Comprising a non-flame retardant pressure sensitive adhesive applied to the support surface;
And further comprising a non-flame retardant foam layer sandwiched between the support surface and the pressure sensitive adhesive.
A flame retardant fastener configured to detachably engage a second fastener,
A requirement of the vertical flammability test (flame retardant test) of the Federal Aviation Regulations (FAR) 25.853 (a) (1) (i) when not attached to a substrate, with a flame of about 60 combustion length in the vertical direction of the fastener in 15 seconds after the addressed seconds is less than 152.4 mm (6 inches), it said after addressed 60 seconds flame fastener to combustion is less than 15 seconds, further, After 60 seconds of exposure to the flame, the drops will not continue to burn for an average of more than 3 seconds after dropping .
And the non-flame retardant pressure sensitive adhesive comprises a foam layer of acrylic foam pressure sensitive adhesive,
Further, the bulk of the foam layer is less than the bulk of the backing layer,
Furthermore, the non-flame retardant foam layer is selected from the group consisting of acrylic resin foam, urethane foam, polyethylene foam, neoprene, and silicone foam,
The flame retardant polymer material is selected from the group consisting of polyolefin, polyamide, polyurethane, polypropylene, and polyethylene.
Flame retardant fasteners.

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