CA2130529A1 - Elastic scrimmed insulating batting - Google Patents

Abstract

There is a provided a stretchable insulating scrim and batting laminate with a first layer of an elastomeric breathable barrier layer which may be a nonwoven microfiber web, and a second layer of an insulating batting material. The layers may be joined adhesively or by needle punching while the elastomeric layer is in the substantially unstretched condition. Optionally, the first and second layers may have between them a layer of an elastomeric breathable film. Such laminates provide at least a 0.35 CLO/mm insulation value and are useful for garments, sleeping bags, and the like, while also providing stretchability. Embodiments having a breathable film exhibit increased water and wind resistance.

Description

2130~29 Docket # 11133 ELASTIC SCRIMMED INSULATING BATTING

BACKGROUND OF THE INVENTION

This invention relates to the field of insulating materials for garments, sleeping bags, etc.
Insulating battings are generally used between layers of material in clothing and other similar applications like, for example, sleeping bags. The layers of material, sometimes referred to as a shell, protect the usually more flimsy insulation batting from abrasion and to some extent weather, while the garment is worn. The batting is usually adhered on at least one side to a scrim material which lends the batting further structural integrity which is needed for shape retention during use and laundering. The scrim material also helps prevent the fibers of the batting from penetrating the apparel shell fabric. After lamination, the scrim and batting laminate is inserted into the shell as a step in completing the article.
An issue with prior scrim and batting laminates that has been addressed to some extent in the art is the issue of weather protection of the laminate. Garment manufacturers often add yet another layer to the scrim and batting laminate in order to protect the laminate from the effects of weather and wind. Such layers have been, for example, materials such as Gore-tex~ fabrics applied to the layer away from the wearer's skin. A drawback to the addition of such a layer is that it requires another step in the manufacturing process which, of course, increases the ultimate cost of the garment being manufactured.
Another issue to be addressed for scrim and batting laminates for clothing is the issue of stretch in the laminate. This is of particular importance in areas of a garment such as the elbows and knees, etc. Gore-tex~
fabrics and traditional scrim and batting laminates do not have as much stretch as would be preferred for many applications.

.

Accordingly, it is an object of this invention to provide a scrim and batting insulating laminate wherein the scrim material lends stretch properties to the laminate.
It is a further object to achieve this property without the step of adding additional layers to provide these properties separately.

SUMMARY

10; According to aspects of this invention a stretchable insulating laminate comprising a first layer which is an elastomeric breathable barrier layer and which is joined to a second layer of an insulating material, and which is substantially unstretched during joining, to produce a laminate with greater than a 0.35 CLO/mm value is provided.
The layers may be joined adhesively or by needle punching with the elastomeric layer in the substantially unstretched condition or by extrusion coating the elastomeric layer onto the second layer. The laminates of this invention have a greater than 0.35 CLO/mm value. Optionally, the first and second layers may have between them a layer of an elastomeric breathable layer which is preferably a film.
The first layer is preferably a nonwoven web.

DETAILED DESCRIPTION

DEFINITIONS

As used herein the term "nonwoven fabric or web"
interchangeably mean a web having a structure of individual fibers, filaments or threads which are interlaid, but not in an identifiable manner. Nonwoven fabrics or webs have been formed from many processes such as for example, meltblowing processes, spunbonding processes, and bonded carded web processes.
As used herein the term "microfibers" means small diameter fibers having an average diameter not greater than .

about 50 microns, for example, having an average diameter of from about 0.5 microns to about 50 microns, or more particularly, microfibers may desirably have an average diameter of from about 0.5 microns to about 20 microns.
As used herein the term "meltblown fibers" means fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into high velocity, usually heated and converging, gas (e.g. air) streams which attenuate the filaments of molten thermoplastic material to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web of randomly disbursed meltblown fibers. Meltblowing is known in the art and is described, for example, in U.S. Patent no.
3,849,241 to Buntin, U.S. Patent no. 4,307,143 to Meitner et al., and U.S. Patent 4,663,220 to Wisneski et al.
As used herein the term "spunbonded fibers" refers to small diameter fibers which are formed by extruding molten thermoplastic material as filaments from a plurality of fine, usually circular capillaries of a spinnerette with the diameter of the extruded filaments then being rapidly reduced as by, for example, in U.S. Patent no. 4,340,563 to Appel et al., and U.S. Patent no. 3,692,618 to Dorschner et al., U.S. Patent no. 3,802,817 to Matsuki et al., U.S.
Patent nos. 3,338,992 and 3,341,394 to Kinney, U.S. Patent nos. 3,502,763 and 3,909,009 to Levy, and U.S. Patent no.
3,542,615 to Dobo et al. Spunbond fibers are generally continuous and larger than 7 microns, more particularly, between about 10 and 20 microns.
As used herein the term "polymer" generally includes but is not limited to, homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc. and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term "polymer" shall include all possible 21~0S2g geometrical configuration of the material. These configurations include, but are not limited to isotactic, syndiotactic and random symmetries.
As used herein the term "recover" refers to a contraction of a stretched material upon termination of a biasing force following stretching of the material by application of the biasing force. For example, if a material having a relaxed, unbiased length of one (1) inch was elongated 50 percent by stretching to a length of one and one half (1.5) inches, the material would have been elongated 50 percent and would have a stretched length that is 150 percent of its relaxed length. If this exemplary stretched material contracted, that is recovered to a length of one and one tenth (1.1) inches after release of the biasing and stretching force, the material would have recovered 80 percent (0.4 inch) of its elongation.
As used herein, the terms "elastic" and "elastomeric"
mean any material which, upon application of a biasing force, is stretchable to a stretched, biased length which is at least about 125 percent (that is at least about one and one quarter) of its relaxed, unbiased length and which will recover at least about 40 percent of its stretch or elongation upon release of the stretching, elongating force. An example which would satisfy this definition of an elastic or elastomeric material would be a one inch sample of a material which is elongatable to at least 1.25 inches and which, upon being elongated to 1.25 inches and released, will return to a length of not more than 1.15 inches. Many elastic materials may be stretched by much more than 25 percent of their relaxed length, for example 100 percent or more, and many of these will return to substantially their original relaxed length, for example, to within 105 percent of their original relaxed length upon release of the stretching, elongating force.
As used herein, the term "stitchbonded" means, for example, the stitching of a material in accordance with - 2130S~9 U.S. Patent 4,891,957 to Strack et al.

As used herein, the term "breathable" means a material having a WVTR of above 8000 gm/m2/day.
5As used herein, the term "barrier" means a material having a hydrohead of above 10 centimeters.
As used herein, the term "scrim" means a lightweight fabric used as a backing material in order to give integrity to a batting. Scrims are often used as the base fabric for coated or laminated products and may be woven or nonwoven.
As used herein, the term "batting" means a soft, bulky assembly of nonwoven fibers or foam. Battings are usually sold in sheets or rolls and used for warm interlinings, comforter stuffings, and other thermal applications.
As used herein, the term "garment" means any type of apparel which may be worn. This includes industrial work wear and coveralls, undergarments, pants, shirts, jackets, gloves, socks, and the like.
20As used herein, the term "medical product" means surgical gowns and drapes, face masks, head coverings, shoe coverings wound dressings, bandages, sterilization wraps, wipers and the like.
As used herein, the term "personal care product" means 2S diapers, training pants, absorbent underpants, adult incontinence products, and feminine hygiene products.
As used herein, the term "outdoor fabric" means a fabric which is primarily, though not exclusively, used outdoors. The applications for which this fabric may be used include car covers, boat covers, airplane covers, camper/trailer fabric, sleeping bags, furniture covers, awnings, canopies, tents, agricultural fabrics and outdoor apparel such as head coverings, industrial work wear and coveralls, pants, shirts, jackets, gloves, socks, and the like.

TEST METHODS
WVTR: The WVTR of a fabric is water vapor transmission rate which gives an indication of breathability or how comfortable a fabric would be to wear.
WVTR is measured in accordance with ASTM Standard Test Method for Water Vapor Transmission of Materials, Designation E-96-80.
Hydrohead: A measure of the liquid barrier properties of a fabric is the hydrohead test. The hydrohead test determines the height of water (in centimeters) which the fabric will support before a predetermined amount of liquid passes through. A fabric with a higher hydrohead reading indicates it has a greater barrier to liquid penetration than a fabric with a lower hydrohead. The hydrohead test is performed according to Federal Test Standard No. l91A, Method 5514.
CLO: The CLO value of a fabric is an indication of its insulating value and is a measure of the maximum temperature attained in an insulated test chamber when one end of the chamber is covered by the fabric. The procedure for determining CLO value is as follows: A sample of fabric is clamped to the square open end of the preheated test chamber of a Reeves Brothers Thermal Conductivity Tester (Reeves Brothers, 1071 Avenue of the Americas, NY, NY). The Reeves Brothers Thermal Conductivity Tester (RBTCT) is a highly insulated chamber containing an air circulating device and electrical heaters with external electrical input controls and temperature measuring means.
The electrical input is a constant 70 watts. The starting temperature is noted and the test continued until the inside temperature remains at the same temperature for at least two consecutive readings 30 minutes apart. The outside or room temperature is maintained at a constant 70F (21C). The higher the equilibrium temperature inside the RBTCT relative to the outside temperature, the better the insulator. CLO value is calculated as 21305~9 1.137/((Btu/hr)/(Tl-T2)-1.02) where the terms are defined as follows:
Tl is the equilibrium temperature in F, T2 is the outside temperature in F (generally 70), and Btu/hr is the energy input to the RBTCT, in this case 70 watts x 3.413 Btu/hr per watt or 238.9 Btu/hr.

The scrim and batting laminate according to this invention has a scrim layer which is a breathable barrier material and may be made according to the meltblowing process from an elastomeric thermoplastic polymer. The process of meltblowing a polymer was described above and a number of relevant patents were cited. It is desired that the laminate of this invention be breathable as defined above. It is also desired that the laminate have sufficient barrier properties to impede the flow of water through the laminate in order to protect the wearer of any garment made with the laminate from rain. Barrier properties as defined above (10 centimeters hydrohead) are believed sufficient for this purpose. Higher hydrohead materials may be used those these materials are generally used for more specialized applications, such as medical products, where prohibition of the passage of blood through the material is of paramount concern.
The basis weight of nonwoven fabrics is usually expressed in ounces of material per square yard (osy) or grams per square meter (gsm) and the fiber diameters useful are usually expressed in microns. The meltblown layers useful in the present invention are made from fibers having diameters of from about 0.5 to 20 microns and have basis weights in the range of from about 0.5 to 5.0 osy. (Note that to convert from osy to gsm, multiply osy by 33.91).
Elastomeric meltblown thermoplastic polymers useful in the practice of this invention may be those made from block copolymers such as polyurethanes, copolyether esters, polyamide polyether block copolymers, ethylene vinyl acetates (EVA), copoly(styrene/ethylene-butylene) and the like. Particularly useful elastomeric meltblown thermoplastic webs are composed of fibers of a material such as disclosed in U.S. Patent 4,707,398 to Boggs, U.S.
Patent 4,741,949 to Morman et al., and U.S. Patent 4,663,220 to Wisneski et al., hereby incorporated by reference. In addition, the elastomeric meltblown thermoplastic polymer layer may itself be composed of thinner layers of elastomeric meltblown thermoplastic polymer which have been sequentially deposited one atop the other or laminated together by methods known to those skilled in the art.
Boggs discloses a web made from a polyetherester having the general formula:

H-( [O-G-C~C] ~ [ (CH2) a~~C~_C]m) n~ (CH2) aOH

where "G" is selected from the group consisting of poly(oxyethylene)-alpha,omega-diol, poly(oxypropylene)-alpha,omega-diol, poly(oxytetramethylene)-alpha,omega-diol and "a", "m" and "n" are positive integers, and wherein said material has an elongation at break of from about 600 percent to 750 percent when measured in accordance with ASTM D-638 and a melt point of from about 350F to about 400F (176 to 205C) when measured in accordance with ASTM D-2117. Commercial examples of such materials are, for example, those known as Arnitel which are available from Akzo Plastics of Arnhem, Holland.
Morman et al. discloses a web made from a polyetherester having the general formula as shown above where IIGI' is selected from the group consisting of poly(oxyethylene)-alpha,omega-diol, poly(oxypropylene)-alpha,omega-diol, poly(oxytetramethylene)-alpha,omega-diol and "a", "m" and "n" are positive integers.
Commercial examples of such polymers are, for example, those known as Hytrel which are available from E.I. duPont de Nemours of Wilmington, Delaware.

- 2130~29 Wisneski et al. discloses a web including microfibers comprising at least about 10 weight percent of an A-B-A' block copolymer where "A" and "A"' are each a thermoplastic endblock which comprises a styrenic moiety and where "B" is an elastomeric poly(ethylene-butylene) midblock, and from greater than 0 weight percent up to about 90 weight percent of a polyolefin which when blended with the A-B-A' block copolymer and subjected to an effective combination of elevated temperature and elevated pressure conditions, is adapted to be extruded, in blended form with the A-B-A' block copolymer. Polyolefins useful in Wisneski et al. may be polyethylene, polypropylene, polybutene, ethylene copolymers, propylene copolymers, butene copolymers, and mixtures thereof. Commercial examples of such materials are, -for example, those known as Kraton~ polymeric materials which are available from Shell Chemical Company of Houston, Texas.
A suitable polyamide polyether block copolymer which may be used in the practice of this invention is that known as Pebax~ and is available from Atochem Inc. Polymers Division (Rilsan~), of Glen Rock, New Jersey (Rilsan~).
The elastomeric layer may also be stitchbonded in accordance with U.S. Patent no. 4,891,957 to Strack et al.
Stitchbonding imparts strength and durability to the stitchbonded product and stitchbonding in the present invention is believed to impart increased abrasion resistance to the laminate. While stitchbonding generally is used to join two or more materials together, in this embodiment of the present invention an elastomeric meltblown layer may be stitchbonded alone and then used in the fabrication of the laminate.
The insulating batting layer of the scrim and batting laminate may be any of those typically used for such purposes. Particularly satisfactory insulating materials are coformed polyolefin and polyester, polyester which may be needle punched, or a laminate of foam and polyester which may be needle punched.

Needlepunching is a method of mechanically coupling diverse layers of material and is well known in the art.
The needlepunching process involves driving a plurality of needles through a fabric from the top, bottom or both.
Such needling results in the entangling of individual fabric filaments with other filaments and such entangling increases the integrity of the nonwoven fabric. Needling can be done on a single fabric where it will increase loft, or a fabric of many layers in order to join together the layers through the entangling of the fiber of the layers.
The insulating batting layer can be of any thickness which may be of use in insulating a garment, sleeping bag or the like. Common thicknesses for such layers are in the range of from about 0.25 to 2.5 inches.
In an alternative embodiment, the laminate may include an additional layer between the elastomeric meltblown scrim layer and the insulating batting layer. This interlayer may be a continuous, liquid impermeable breathable film which is preferably an elastomeric material and which may be made according to methods known to those skilled in the art.
The film which may be used in this laminate has a high water vapor transmission rate (WVTR), at least 8000 gm/m2/day, and so allows water vapor to pass through to cool the skin yet does not allow the penetration of liquid water to a significant degree. The film also significantly impedes the flow of air through the laminate and so provides a good wind barrier to any garment into which it is incorporated.
The continuous liquid impermeable film useful in this invention may be one such as that made from polyolefins, polyamides, polyesters, polyurethanes, polyethers, polyetheresters, co-polyesters, co-polyamides or urethanes.
A particularly useful film is available from the Dupont Company of Wilmington, Delaware, as Hytrel~ 8171 and is co-p~lyester with a WVTR of about >10,000 gm/m2/day.

The layers of the laminates may be joined by a number of methods, for example by needlepunching, adhesive attachment, extrusion coating and any other acceptable means.
5Needlepunching has been described above and in the case of a laminate involves driving needles through one fabric layer into another in order to physically entangle fibers of one layer with another.
Extrusion coating is the process wherein one layer is extruded and produced directly upon another layer. For example, meltblown fibers could be produced directly onto a polyester batting. In this case the meltblown fibers would entangle and adhere to the polyester fibers to some degree since the meltblown fibers would still be semi-molten as they contact the polyester and would solidify and cool completely while in intimate contact with the polyester layer. In extrusion coating the elastomeric would be in the unstretched condition.
Adhesive attachment may also be used using any adhesive which is suitable for that purpose. An important property of the adhesive is that it not interfere with the elasticity (e.g. recoverability) of the laminate. The adhesive may be heat activated to achieve bonding and moreover powder, aqueous or solvent based adhesives may be used.
Adhesive which may be used include urethanes, acrylics, latexes, copolyamides, copolyesters, and polyethylenes. One particularly suitable adhesive is that available from the Huls Company (Germany) and is a ter-30polyamide powder with a particle size of 300 to 500 microns marketed under the name T350.
Needlepunching a film would destroy any barrier properties it may possess, therefore, if a film is absent, the elastomeric layer and the insulation layers may be joined by needle punching as described above, without the need for adhesive, though it may be optionally used also.

213052~
-The lamination of stretched elastic webs onto other, (non-elastic) webs has been taught, for example, in U.S.
Patent 4,720,415 to Vander Wielen. According to Vander Weilen, a stretched elastic web is bonded to the non-- 5 elastic web and immediately released, resulting in gathering or puckering of the fabric.
Since the fabric of the instant invention is to be used in clothing or other personal insulating applications, e.g.; sleeping bags, such puckering may be undesirable.
Therefore, it is preferred that the fabric be unstretched when bonded, or if taut when bonded, not pulled so greatly as to cause such gathering or puckering after bonding.
A widely used measure of the thermal resistance of a fabric is known as the CLO value and the procedure for determining CLO is given above. Since it is generally desired to have clothing as thin and lightweight as possible, the CLO value per thickness is a key indicator of the insulating value of a fabric.
A series of samples were tested for CLO value and thickness. The results of this testing are presented in Table 1. Note that all layers of polyetherester fabric are produced according to U.S. Patent 4,707,398 to Boggs and that samples 1 through 6 are examples of this invention.
In those samples in which an adhesive was employed, the adhesive was Huls' T350.

SAMPLES

Sample 1 - An elastic laminate of 3.0 osy needled polyester staple fiber batting thermally powder bonded to a 1.5 osy layer of taut polyetherester fabric.
SamPle 2 - An elastic laminate of 3.0 osy needled polyester staple fiber batting thermally powder bonded to a 1.5 osy layer of loose polyetherester fabric.
- Sample 3 - An elastic laminate of 3.0 osy needled polyester staple fiber batting thermally powder bonded to -a 1.5 osy layer of loose polyetherester fabric with a layer of HytrelX film between.
Sample 4 - An elastic laminate of 3.0 osy polyester staple fiber needled into a foam scrim batt and thermally powder bonded to a 1.5 osy taut polyetherester fabric.
SamPle 5 - An elastic laminate of 3.0 osy polyester staple fiber needled into a foam scrim batt and thermally powder bonded to a 1.5 osy loose polyetherester fabric.
SamPle 6 - An elastic laminate of 3.0 osy polyester staple fiber needled into a foam scrim batt and thermally powder bonded to a 1.5 osy loose polyetherester fabric and a layer of HytrelX film between.
Sample 7 - An elastic needle punched layer of 1.5 osy polyetherester fabric.
Sample 8 - A layer of Thinsulate~ CS100 material.
This material is commercially available from the Minnesota Mining and Manufacturing Company of Minneapolis, MN.
SamPle 9 - A layer of Thinsulate~ CS200 material.
This material is commercially available from the Minnesota Mining and Manufacturing Company of Minneapolis, MN.
SamPle 10 - A layer of synthetic down. This material is commercially available from the Albany International Company of Albany, NY, under the trade designation Primaloft.
Sample 11 - A layer of Polarguard~ material. This material is commercially available from the Hoechst Celanese Company.
Sam~le 12 - A layer of Thermoloft Type cX material.
This material is commercially available from the E.I.
DuPont Company of Wilmington, DE.
Sample 13 - A layer of Thermolite 150~ material. This material is commercially available from the E.I. DuPont Company of Wilmington, DE.

Table 1 Sample CL0 Thickness(mm) CL0/mm 1 1.021 1.578 0.64

2 0.987 1.713 0.58

3 1.075 1.057 1.02

4 1.112 2.748 - 0.40 1.112 2.513 0.44 6 1.151 3.073 0.37 7 1.021 2.870 0.36 8 1.390 5.172 0.27 9 1.949 9.082 0.21 1.366 3.242 0.42 11 1.151 16.242 0.07 12 0.747 13.640 0.05 13 0.816 7.272 0.11 As can be seen from Table 1, the materials of this invention not only provide the desirable qualities such as breathability, barrier, wind resistance and stretchability, but also provide very high CL0/thickness values, generally above 0.35 CL0/mm. Such properties are desirable in garments, sleeping bags and other similar applications.
While the invention has been described in conjunction with a specific embodiment, it is to be understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, this invention is intended to embrace all such alternatives, modifications and variations which fall within the scope of the appended claims.

Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A stretchable insulating laminate comprising a first layer which is an elastomeric breathable barrier layer and which is joined to a second layer of an insulating material, and wherein said elastomeric layer is substantially unstretched during said joining, and wherein said laminate has greater than a 0.35 CLO/mm value.

2. The insulating laminate of claim 1 wherein said elastomeric layer has a basis weight of 0.20 to 6.0 ounces/yard.

3. The insulating laminate of claim 1 wherein said elastomeric layer has been stitchbonded prior to incorporation into said laminate.

4. The insulating laminate of claim 1 which, upon being elongated to 1.25 inches and released, will return to a length of not more than 1.15 inches.

5. The insulation laminate of claim 1 wherein said layers are joined together by a method selected from the group consisting of needlepunching, adhesive attachment, and extrusion coating.

6. The insulating laminate of claim 1 wherein said second layer is an insulating material selected from the group consisting of polyester, needle punched polyester, foams, and combinations thereof.

7. The insulating laminate of claim 1 wherein said elastomeric layer is a web comprised of fibers which are made from polymers selected from the group consisting of polyurethanes, copolyetheresters, polyamide polyether block copolymers, ethylene vinyl acetates (EVA) and copoly(styrene/ethylene-butylene).

8. The insulating laminate of claim 7 wherein said elastomeric web fibers range from 0.5 to 12 microns in diameter.

9. The insulating laminate of claim 1 further comprising an additional layer of an elastomeric breathable barrier layer between said first and second layers.

10. The insulating laminate of claim 9 where said additional elastomeric layer is a film comprised of polymers selected from the group consisting of polyurethanes, copolyether esters, ethylene vinyl acetates (EVA) and copoly(styrene/ethylene-butylene).

11. The insulation laminate of claim 9 wherein said layers are joined together by a method selected from the group consisting of needlepunching, adhesive attachment, and extrusion coating.

12. The insulating laminate of claim 9 which is present in articles selected from the group consisting of garments and outdoor fabrics.

13. The insulating laminate of claim 12 wherein said article is a garment and said garment is a jacket.

14. The insulating laminate of claim 12 wherein said article is an outdoor fabric and said outdoor fabric is a sleeping bag.

15. A stretchable insulating scrim and batting laminate comprising a first layer which is an elastomeric meltblown nonwoven web comprised of fibers which are made from copolyetheresters, a second layer of an insulating material, and a layer of an elastomeric breathable film made from a copolyetherester between said first and second layers, and wherein said layers are joined together with an adhesive and wherein said laminate has greater than a 0.35 CLO/mm value.