KR20040094804A - Insulating material - Google Patents

Abstract

The insulation consists of about 20 to 60% by weight low melt bicomponent fibers, 10 to 40% by weight high melt bicomponent fibers and 20 to 60% by weight staple fibers. The insulation provides an unprecedented combination of strength, sound insulation and heat dissipation characteristics that were not available in the prior art.

Description

Insulation Material {INSULATING MATERIAL}

Acoustic and thermal liners for application in vehicles are well known in the art. The liner relies on both sound absorption, which is generally the ability to absorb incident sound waves, and transmission loss, which is the ability to reflect incident sound waves, to reduce sound. The liner also relies on thermal barrier properties to prevent or reduce thermal conduction of the vehicle from the various heat sources (eg engine, conduction and exhaust systems) to the passenger compartment. The insulation is commonly used as hood liners, dash liners, and firewall liners. More recently, the liner has been used on an engine cover closer to its source to reduce the engine's sound.

Examples of sound insulation and insulation in the form of liners are disclosed in a number of prior art patents, including US Pat. No. 4,851,283 to Holtrop et al. And US Pat. No. 6,008,149 to Copperwheat. As is evident in the inventory of the above two patents, technicians generally have (a) one or more layers to provide the desired sound insulation and insulation properties that enable simple and convenient installation and proper functionality over a long useful life and (b) We have found a need to construct the liner from a laminate comprising one or more additional layers to provide the desired mechanical strength properties.

In particular, to protect the layers of various laminates together, a number of adhesives, adhesive nets, and bonding fibers have been developed for many years, but laminated liners and insulations have the risk of inherent peeling and breaking. Indeed, the potential is largely due to the harsh working environment in which the liner and insulation are exposed. Many liners and insulation materials are designed to be located near and / or to block high heat sources such as parts of engines, conduction and exhaust systems. As a result, liners and insulators are often exposed to temperatures above 200 ° F., which tend to degrade the adhesive or binder over time.

In addition, many liners and insulators are exposed to water from the surface of the road, which tends to be attracted to the contact surface between layers of the liner or insulator by capillary action. The water adversely affects the integrity of the adhesive layer over time. This is especially true if the water from the road contains corrosive and destructive solution salts or other chemicals.

Thus, a need has been recognized for a hood, dash, firewall or engine shroud liner that includes an unlaminated sound insulation and thermal insulation layer of polymer fibers that avoids all the inherent potential of exfoliation. The liner is suitable for use in the hot working environment of the engine compartment and can provide the desired mechanical strength and robustness for ease of installation and the desired sound insulation and insulation properties.

FIELD OF THE INVENTION The present invention generally relates to the field of sound insulation and insulation, and more particularly to a unique novel insulation of low melt and high melt bicomponent fibers that exhibit a unique blend of structural and sound insulation properties.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the invention, and together with the foregoing description, explain the principles of the invention. In the drawing:

1 is a schematic side view of one possible implementation of the present invention;

2-4 are schematic side views of another possible alternative implementation of the present invention;

5 is a schematic illustration comparing the flexural strength in the machine direction of the structure / soundproof material of the present invention with the standard state of the prior art polymer formulations;

FIG. 6 is a schematic illustration comparing the flexural strength in the cross machine direction of the structure / soundproof material of the present invention with the standard state of a polymer formulation of the prior art.

Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.

Detailed description of the invention

The present invention relates in particular to insulating materials which are of particular note of a combination of structural and acoustical properties. In particular, as described below, the insulating material (1) maintains the same acoustics for the standard formulation, (2) provides high temperature performance, and (3) has a minimal cost increase over the standard formulation, At least 100% improvement over the standard formulation in modulus of elasticity. In the past, in order to improve the structural properties, it was generally necessary to give up a considerable level of acoustic performance or to use much more expensive fibers, or both, but the present invention does not sacrifice acoustic properties or low production costs, but modulus of elasticity A significant increase of has been achieved, which represents a significant advance in the prior art.

The insulation of the present invention contains about 20 to 60% by weight low melt bicomponent fibers, 10 to 40% by weight high melt bicomponent fibers and 20 to 60% by weight staple fibers. The molten fibers comprise an average fiber diameter of about 10 to 30 microns, or generally 16 to 24 microns and most generally 18 to 22 microns. The material has a density of about 1.0 to 10.0 pcf (16.02 to 160.2 kg / m 3) and a flexural strength of about 40 to 1200 psi (275.79 to 8273.71 kPa).

For clarity, the bicomponent fiber consists of the main polymer component and the binder polymer component. The bicomponent fiber may be formed from sheath-core fibers in which the main polymer component forms a core material and the binder polymer component forms a sheath around the center. However, it should be understood that other arrangements may be used, such as side-by-side arrangements. In another arrangement, the binder polymer component binds the bicomponent fibers and staple fibers themselves and with each other.

The binder polymer component of the bicomponent fiber has a softening point lower than that of the main polymer component, so that the two materials react differently upon heating. When heated to a temperature above the softening point of the binder polymer component or below the softening point of the main polymer component, the binder components soften and become tacky to bond various bicomponent fibers in contact with each other and in contact with the staple fibers. As long as the temperature does not rise as high as the softening point of the main polymer component, the component is in the form of fibers.

Low melt bicomponent fibers include copolyester / polyethylene terephthalate (CoPET / PET), poly 1,4 cyclohexanedimethyl terephthalate / polyethylene terephthalate (PCT / PET), poly 1,4 cyclohexanedimethyl terephthalate / polypropylene (PCT / PP), glycol-modified polyethylene terephthalate / polyethylene terephthalate (PETG / PET), propylene / polyethylene terephthalate (PP / PET), nylon 6 / nylon 66, polyethylene / glass, or differential melt flow temperatures It is selected from the group of materials consisting of other blends of polymers, including polymers / glass and polymers / natural fibers to provide. The bicomponent fibers can be in any of a variety of configurations that provide acceptable fiber bonds, such as skin-centered, side by side, segmented pies, and the like. Low melt bicomponent fibers are described as having a melt flow temperature of about 100 ° C. to 130 ° C. (212 ° F. to 266 ° F.).

High melt bicomponent fibers include copolyester / polyethylene terephthalate (CoPET / PET), poly 1,4 cyclohexanedimethyl terephthalate / polyethylene terephthalate (PCT / PET), poly 1,4 cyclohexanedimethyl terephthalate / polypropylene (PCT / PP), glycol-modified polyethylene terephthalate / polyethylene terephthalate (PETG / PET), propylene / polyethylene terephthalate (PP / PET), nylon 6 / nylon 66, or polymers providing differential melt flow temperatures Other combinations of materials. The bicomponent fibers can be in any of a variety of configurations that provide acceptable fiber bonds, such as skin-centered, side by side, segmented pies, and the like. The high melt binary component is described as having a melt flow temperature of about 170 ° C. to 200 ° C. (338 ° F. to 392 ° F.). Bicomponent fibers, generally described as crystalline or semicrystalline, having a melt flow temperature of about 150 ° C. to 180 ° C. (302 ° F. to 356 ° F.) may partially or wholly replace high melt bicomponent fibers.

The insulation provides unprecedented sound insulation with a flexural strength of about 40 to 1200 psi (275.79 to 8273.71 kPa). Specifically, the insulating material is all 0.17 to 0.24 at a frequency of 500 Hz, 0.29 to 0.63 at a frequency of 1000 Hz, 0.70 to 0.94 at a frequency of 2000 Hz and 0.71 at a frequency of 4000 Hz at a density of 2 pcf (32.04 km / g ³ ). To a sound absorption coefficient of 0.99. In addition, the insulating material has a thermal conductivity value of about 0.20 to 0.30 at a density of 2 pcf (32.04 km / g ³ ). Thus, it should be appreciated that the insulation provides good sound insulation and structural properties as well as good thermal insulation properties.

The staple or bulking fibers used in the insulation material are selected from the group of materials consisting of polyester fibers, polyethylene fibers, polypropylene fibers, nylon fibers, rayon fibers, glass fibers, natural fibers and mixtures thereof.

Insulation materials of the present invention can be used in a number of applications that require unparalleled structural, sound insulation, and thermal insulation properties of the present invention, when suitable for a particular application. For example, the insulating material of the present invention can be used in the construction of a hood, dash, firewall or engine shroud liner, as shown in Figures 1-4 of the present invention.

The liner 10 shown in FIG. 1 includes a sound insulation and heat insulation layer 12 of the insulation of the present invention. More specifically, the single, unlaminated layer 12 is endowed with the necessary mechanical strength and robustness to enable easy installation and the desired sound insulation and thermal insulation properties. Advantageously, all the above advantages are achieved in the low weight liner 10, which can also be used in small vehicles where manufacturers want to reduce the weight as much as possible because of fuel economy problems.

In the first alternative implementation shown in FIG. 2, the liner 10 also includes a single, unlaminated sound insulation and insulation layer 12 of the insulation of the present invention. Layer 12 comprises a relatively dense, unlaminated or single skin 14 of the insulation, along one or more surfaces of the insulation.

Advantageously, the high density skin 14 does not delaminate from the layer 12 under environmental conditions present in the engine compartment and also provides structural integrity and strength to the liner 10 which significantly assists in handling and assembling the parts upon installation. Add. Also, the high density skin 14 is more aesthetically pleasing. In addition, for many applications, high density skin 14 eliminates the need to provide additional surface layers of other types of fibrous materials. This substantially eliminates all the potential for breakage of the lining due to delamination. It also results in a liner 10 that is solely made of one material, ie fully recyclable.

In addition, the skin can be formed in its desired form upon forming the liner 10 with a high temperature platen, so no additional processing step is required. This lowers production costs compared to liners with structures or other facings in which the surface has to be attached to the sound insulation and insulation layers in separate processing steps.

In another embodiment shown in FIG. 3, the liner 10 is a single, unlaminated sound insulation and insulation layer of the insulation of the present invention with a facing layer 16 over the first surface 18 of the sound insulation and insulation layer. And (12). Facing layer 16 may be made of a polymeric material selected from the group consisting of polyester, rayon, polyethylene, polypropylene, ethylene vinyl acetate, polyvinyl chloride, and mixtures thereof.

In another alternative implementation shown in FIG. 4, the liner 10 includes a first facing layer 16 covering its first surface 18 and a second facing layer covering its second, opposite surface 22 ( 20), a single, non-laminated sound insulation and thermal insulation layer 12 of the insulation of the present invention, as described above together. The second facing layer 20 may be composed of the same or different material as the first facing layer 16. Preferably the first and second facing layers have a weight of about 0.50 to 3.00 oz / sq yd (16.95 to 101.72 g / m 2).

According to another aspect of the invention, the sound insulation and thermal insulation layer 12 may be natural white or include all suitable forms of pigments or pigments to provide gray or black color. Alternatively, the sound insulation and thermal insulation layer 12 may comprise any suitable pigment or pigment so as to make the colors of the first and / or second facing layers 16, 20 and / or paint colors of the vehicle quite similar. Can be. This provides a significant aesthetic benefit. In particular, when the liner 10 is molded under heat and pressure to overlap the hood, firewall or other suitable body frame or engine compartment superstructure, the liner 10 is often deep drawn at one or more points. . The deep drawing tends to unfold the weaving of the fabric facings 16, 20, thereby exposing a portion of the surfaces 18, 20 of the lower part of the sound insulation and thermal insulation layer to light. If the sound insulation and thermal insulation layer 12 does not substantially match the colors of the facing layers 16, 20, this causes undesirable color differences in the deeply drawn regions. In contrast, by matching the color of layer 12 with facings 16 and 20, the color difference can be significantly eliminated.

It should also be appreciated that in use, the facing layers 16, 20 may be rugged or partially ruptured, exposing a portion of the surface of the underlying sound insulation and thermal insulation layer 12. Once again, by harmonizing the color of layer 12 with facings 16 and 20, all color differences are significantly removed and attention is not easily directed to the damaged area. Thus, the overall improved aesthetic appearance is maintained over the useful life of the liner 10.

The insulation of the present invention is produced according to processing steps generally known in the art.

The fibers need to be mixed and thermally bonded in a given proportion to form a semi-rigid blanket. The fibers are typically packaged in 500 to 700 lb. (226.79 to 317.51 kg) packaging. The fibers can be mixed from the fiber feeder in the proper proportions and allowed to be packed together, but in general, each of the three fibers is packed separately. For the purposes of this description, it is assumed that the fibers are packaged separately. In general, each packaged fiber needs to be "opened" by a package opening system common in the industry. The open system inflates the fiber and sends the appropriate amount of fiber by weight to the mixing zone. The swelling separates the dense fiber mass and enhances fiber-to-fiber contact. The mixing zone evenly distributes different fibers according to the desired fiber ratio.

Once mixed, the fibers are evenly distributed on the delivery system to form an unbonded "sheet" or "blanket" of the evenly distributed fibers. Before the sheet enters the thermal bonding oven, a thermally activated powder binder or other supplementary bonding method may be added in the fiber mixing or delivery step. The oven is built such that heated air passes through the fiber pack and the fiber reaches a temperature sufficient to activate the binding fibers and / or other bonding materials. If the blanket material is to be produced for subsequent molding applications, the oven temperature only needs to be high enough to activate at least some of the low melt bonded fibers. Subsequent molding operations only need to reach temperatures sufficient to activate the higher molten fibers. If no subsequent molding operation takes place, the oven needs to be set at a temperature sufficient to activate both low melt and high melt fibers—in this case the temperature required is above 180 ° C. (356 ° F.). Once the fiber has reached the appropriate temperature, the oven or subsequent oven area should be able to lower the temperature below the activation point of the binding material, in this case approximately 100 ° C. (212 ° F.). The thickness of the desired blanket is generally established in the oven treatment. After leaving the oven, additional binding material, such as powder, can be added to the fiber blanket, and other treatments can also take place that densify one or both sides of the blanket.

The blanket can now be manipulated and used "as is" for structure-acoustic applications, and can also be molded later to produce parts of simple or highly complex forms. Molding methods can vary among those commonly used in the molding industry for thermoplastic materials. One of the methods preheats the blanket material to a temperature sufficient to (re) activate all of the bonding material, and then quickly transfer the heated blanket to a low temperature forming tool and the fiber temperature is low melt bonded. A part of the pressure is compressed until the fiber is below the activation point of the fiber.

For the samples used for the structural tests in the examples below, no subsequent molding operation was used to obtain the desired test thickness.

The following examples are presented to further illustrate the invention, but are not intended to limit the invention thereto.

[Summary of invention]

Accordingly, the present invention relates to insulating materials exhibiting an unprecedented combination of sound insulation and strength / structural properties. The insulation contains about 20 to 60% by weight low melt bicomponent fibers, 10 to 40% by weight high melt bicomponent fibers and 20 to 60% by weight staple fibers. The melt comprises an average fiber diameter of about 10 to 30 microns, more typically 16 to 24 microns and most generally 18 to 22 microns. The material has a density of about 1.0 to 10.0 pcf (16.02 to 160.2 kg / m 3) and a flexural strength of about 40 to 1200 psi (275.79 to 8273.71 kPa). More specifically, the insulating material has a sound absorption coefficient as follows: All at a density of 2 pcf (32.04 km / g ³ ), 0.17 to 0.24 at a frequency of 500 Hz, 0.29 to 0.63 at a frequency of 1000 Hz, 2000 Hz 0.50 to 0.94 at a frequency of 0.71 and 0.99 at a frequency of 4000 Hz.

Further describing the present invention, the insulation has a thermal conductivity value of about 0.20 to 0.30 at a density of 2 pcf (32.04 km / g ³ ). Staples or bulking fibers are selected from the group of materials consisting of polyester fibers, polyethylene fibers, polypropylene fibers, nylon fibers, rayon fibers, glass fibers, natural fibers and mixtures thereof.

Low melt bicomponent fibers include copolyester / polyethylene terephthalate (CoPET / PET), poly 1,4 cyclohexanedimethyl terephthalate / polyethylene terephthalate (PCT / PET), poly 1,4 cyclohexanedimethyl terephthalate / polypropylene (PCT / PP), glycol-modified polyethylene terephthalate / polyethylene terephthalate (PETG / PET), propylene / polyethylene terephthalate (PP / PET), nylon 6 / nylon 66, polyethylene / glass, or differential melt flow temperatures It is selected from the group of materials consisting of different combinations of polymers, including polymers / glass and polymers / natural fibers to provide. The bicomponent fibers can be in any of a variety of configurations that provide acceptable fiber bonds, such as skin-centered, side by side, segmented pie, and the like. Low melt bicomponent fibers are described as having a melt flow temperature of about 100 ° C. to 130 ° C. (212 ° F. to 266 ° F.).

High melt bicomponent fibers include copolyester / polyethylene terephthalate (CoPET / PET), poly 1,4 cyclohexanedimethyl terephthalate / polyethylene terephthalate (PCT / PET), poly 1,4 cyclohexanedimethyl terephthalate / polypropylene (PCT / PP), glycol-modified polyethylene terephthalate / polyethylene terephthalate (PETG / PET), propylene / polyethylene terephthalate (PP / PET), nylon 6 / nylon 66, or polymers providing differential melt flow temperatures Other combinations of materials. The bicomponent fibers can be in any of a variety of configurations that provide acceptable fiber bonds, such as skin-centered, side by side, segmented pies, and the like. High melt bicomponent fibers are described as having a melt flow temperature of about 170 ° C to 200 ° C. Bicomponent fibers, which are generally described as crystalline or semicrystalline, having a melt flow temperature of about 150 ° C. to 180 ° C. (302 ° F. to 356 ° F.), may partially or wholly replace high melt bicomponent fibers.

The structural / acoustic formulations of the insulation of the present invention were tested and tested with 40% low melt bicomponent fibers having an average fiber diameter of 14.3 microns, 30% staple (bulking) fibers with an average fiber diameter of 12.4 microns, and 50.0 microns. Compared to a standard formulation of 30% of staple (bulking) fibers having an average fiber diameter. In addition, the standard formulation had an average fiber diameter of 30.0 microns. The flexural strength tests of the structural / acoustic formulations and standard formulations of the insulation of the invention were then performed according to ASTM D1037 static three point bends. The test results are clearly illustrated in FIGS. 5 and 6. FIG. 5 shows the flexural strength of the two formulations in the machine direction and FIG. 6 shows the flexural strength of the two formulations in the semi-machine direction. In both cases, it should be recognized that the structural / acoustic formulation of the insulation of the present invention provides an improvement of at least 100% over the standard formulation tested in modulus of elasticity.

The structural / acoustic formulations of the insulation of the present invention also provide sound absorption coefficients somewhat better than the sound absorption coefficients provided by standard formulations, which provide significant enhancement in strength and enhanced sound insulation performance. As such, the present invention represents a significant advance in the prior art.

In summary, a number of advantages emerge from using the concepts of the present invention. Insulation materials are provided that provide an unparalleled combination of structural strength, sound insulation and thermal insulation properties. The insulation is particularly suitable for use as a hood, dash, firewall or engine shroud liner. The insulation provides mechanical strength and robustness that facilitates operation and installation, while providing insulation and sound insulation properties that are consistently and reliably maintained over a long useful life even in high temperature and high humidity working environments of the engine compartment. This performance characteristic was not possible with previous liners that included a single, unlaminated sound insulation and insulation material.

The foregoing description of the preferred implementation of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed.

The above implementation provides the best illustration of the principles of the present invention and, accordingly, one of ordinary skill in the art, together with various modifications suitable for the particular use in which it is envisioned, makes practical application for use of the present invention in various implementations possible. It was chosen and described to provide. For example, crystalline or semicrystalline bicomponent fibers having a melt flow temperature of about 150 ° C. to about 180 ° C. may partially or wholly replace high melt bicomponent fibers. All such modifications and variations are intended to fall within the scope of the present invention as determined by the appended claims when they are interpreted in accordance with the scope to which they are appropriately, legally and fairly imparted.

Claims (20)

Insulation comprising about 20 to 60 wt% low melt bicomponent fibers, 10 to 40 wt% high melt bicomponent fibers and 20 to 60 wt% staple fibers. The insulation of claim 1 comprising an average fiber diameter of about 10 to 30 microns. The insulation of claim 1 comprising an average fiber diameter of about 16 to 24 microns. The insulation of claim 1 comprising an average fiber diameter of about 18 to 22 microns. The insulating material of claim 1 having a density of about 1.0 to 10.0 pcf (16.02 to 160.2 kg / m 3) and a flexural strength of about 40 to 1200 psi (275.79 to 8273.71 kPa). The insulating material according to claim 5, which has a sound absorption coefficient as follows: freq (Hz) Sound absorption coefficient at density 2 pcf (32.04 kg / ㎥) 500 0.17-0.24 1000 0.29-0.63 2000 0.50-0.94 4000 0.71-0.99 7. The insulating material of claim 6 having a thermal conductivity value of about 0.20 to 0.30 at a density of 2 pcf (32.04 kg / m 3). The insulator of claim 1, wherein said low melting and high melting bicomponent fibers are concentric sheath / center CoPET / PET. The insulating material according to claim 8, wherein the staple fibers are selected from the group of materials consisting of polyester fibers, polyethylene fibers, polypropylene fibers, nylon fibers, rayon fibers, glass fibers, natural fibers and mixtures thereof. The insulating material according to claim 1, which has a sound absorption coefficient as follows: freq (Hz) Sound absorption coefficient at density 2 pcf (32.04 kg / ㎥) 500 0.17-0.24 1000 0.29-0.63 2000 0.50-0.94 4000 0.71-0.99 The insulating material of claim 10 having a thermal conductivity value of about 0.20 to 0.30 at a density of 2 pcf (32.04 kg / m 3). The insulating material according to claim 11, wherein the staple fibers are selected from the group of materials consisting of polyester fibers, polyethylene fibers, polypropylene fibers, nylon fibers, rayon fibers, glass fibers, natural fibers and mixtures thereof. The insulating material of claim 1 wherein said staple fibers are selected from the group of materials consisting of polyester fibers, polyethylene fibers, polypropylene fibers, nylon fibers, rayon fibers, glass fibers, natural fibers, and mixtures thereof. 15. The method of claim 13 wherein the low melt bicomponent fibers comprise copolyester / polyethylene terephthalate, poly 1,4 cyclohexanedimethyl terephthalate / polyethylene terephthalate, poly 1,4 cyclohexanedimethyl terephthalate / polypropylene, glycol- Insulation material selected from the group of materials consisting of modified polyethylene terephthalate / polyethylene terephthalate, propylene / polyethylene terephthalate, nylon 6 / nylon 66, polyethylene / glass, polymers / natural fibers and mixtures thereof to provide differential melt flow temperatures. 15. The insulator of claim 14, wherein said bicomponent fibers are selected from the group consisting of sheath-core, side-by-side, segmented pies, and mixtures thereof. The insulator of claim 14, wherein the low melt bicomponent fiber has a melt flow temperature of about 100 ° C. (212 ° F.) to about 130 ° C. (266 ° F.). The method of claim 13 wherein the high melt bicomponent fibers are copolyester / polyethylene terephthalate, poly 1,4 cyclohexanedimethyl terephthalate / polyethylene terephthalate, poly 1,4 cyclohexanedimethyl terephthalate / polypropylene, glycol- Insulation material selected from the group of materials consisting of modified polyethylene terephthalate / polyethylene terephthalate, propylene / polyethylene terephthalate, nylon 6 / nylon 66, and mixtures thereof to provide differential melt flow temperatures. 18. The insulator of claim 17, wherein said high melt bicomponent fibers are in a configuration selected from the group consisting of skin-centered, side by side, separable segmented pies and mixtures thereof. 18. The insulation of claim 17 wherein the high melt bicomponent fiber has a melt flow temperature of about 170 [deg.] F. (338 [deg.] F.) to about 200 [deg.] F. (392 [deg.] F.). 18. The insulator of claim 17, wherein the crystalline / semicrystalline bicomponent fibers having a melt flow temperature of about 150 ° C. (302 ° F.) to about 180 ° C. (356 ° F.) partially or wholly replace the high melt bicomponent fibers.