MXPA05002821A - Improved sound absorbing material and process for making - Google Patents

Abstract

A sound absorbing material having a homogenous mixture of an organic man-made fiber, an inorganic man-made fiber, a co-binder, and a cellulose material wherein the organic man-made fiber is polyester, the inorganic man-made fiber is fiberglass, and he co-binder is a thermo-setting resin. The cellulose material may include Kaolin clay and/or boric acid.

Description

IMPROVED SOUND ABSORBENT MATERIAL AND PROCESS FOR PRODUCTION CROSS REFERENCE TO PREVIOUS APPLICATION This international PCT patent application claims priority and benefit of the provisional patent application of the U.S.A. Serial No. 60 / 410,608, filed September 13, 2002. BACKGROUND OF THE INVENTION The present invention relates to an improved sound-absorbing material and more specifically to a sound-absorbing material comprising a mixed matrix of fibers made by man, a coagglutinant and fibrous cellulose or material based on cellulose. Automotive manufacturers typically use sound absorbing materials to line various compartments of an automobile, such as the engine compartment, to inhibit noise from entering a cabin or interior portion of a vehicle. The sound absorbing material can also line the interior of the vehicle, such as the upholstery inside the roof of a vehicle and the flat base panel of a vehicle, to absorb the sound created from inside the cab. Car manufacturers require that the material meet specific standards.

For example, the sound absorbing material must withstand certain temperatures without burning or melting. To test this standard, the sound absorbing material is subjected to a flame test. In the open flame test, a sound-absorbing material is introduced to an open flame for a specific period of time at a specific distance from the sample of the material. It is preferable that the sound absorbing material should not melt or burn, or if the material is burned should have a self-extinguishing characteristic. Pure polyester is known in the art for use with a sound absorbing material and generally has good sound absorbing characteristics. However, it has been found that pure polyester does not perform well in the open flame test because the material burns and melts at high temperatures. Additionally, pure polyester generally softens and warps at temperatures above 232.2 ° C (400 ° F). In an attempt to improve the performance of the sound-absorbing material in the flame test, as well as to increase the sound-absorbing characteristics, some portion of glass fibers are added to the polyester-based sound-absorbing material. Although glass fibers perform in the flame test and have had good absorption characteristics of sound, they have a main disadvantage. Glass fibers can cause irritation to human skin, eyes and respiratory systems. In general, the smaller the size of the fibers, the stronger the irritation will be. In this way, although glass fibers are good in one respect they are not so attractive in others. In view of the deficiencies in known materials, it is apparent that a sound absorbing material is required to have good sound-absorbing qualities, that it has a diminished amount of glass fibers that pass the moisture absorption test, and that it passes the tests of flame from automotive manufacturers. SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved sound absorbing material that will not burn when exposed to an open flame or hang, warp or buckle when exposed to temperatures above 232.2 ° C (450 ° F). . A further objective of the present invention is to provide an improved sound absorbing material that limits moisture absorption. A still further objective of the present invention is to provide an absorbent material of Improved sound that does not require the use of a front fabric. Still another additional objective of the present invention is to provide an improved sound absorbing material having mixed fibrous cellulose. More particularly, the improved sound-absorbing material of the present invention includes a mixed matrix of at least organic first man-made fibers., and preferably first and second inorganic man-made fibers. The first, at least, preferably matrix of first and second man-made fibers, are further mixed with a co-binder such as a phenolic resin, phenol-formaldehyde and more particularly a powdered phenolic resin. Alternatively, other thermosetting resins can be used as a co-binder including acrylic resin, epoxy resins, vinyl esters, urethane silicones and other interlaxable rubber and plastic polymers, and resins and the like. These resins can be in the form of powder, latex, oil base or solvent base, or they can be liquid polymers. The matrix further comprises fibrous cellulose or fibrous cellulose-based material that is low density but provides increased acoustic performance and increased tensile strength. A material of Pulp-based cellulose is inexpensive compared to other acoustic fibers. Additionally, cellulose can be mixed with kaolin clay to affect a fiber that does not absorb moisture. Preferably, the clay may be about 15% by weight of the cellulose mixture. In addition, boric acid can be added to inhibit the growth of mold and bacteria, as well as provide the flame retardant or flame retardant feature to the matrix. This is a highly convenient feature since the absorption of moisture can lead to mildew and unpleasant odors. However, other flame retardants can be used. The first organic fibers and the second inorganic fibers can be polyester fibers and glass fibers, respectively. The glass fibers may be selected from a plurality of types of glass fibers including rotating glass fibers, flame attenuated glass fibers and in a preferred embodiment textile glass fibers. However, in an alternate embodiment, the matrix does not include glass fibers. The polyester can be up to 70% by weight and preferably about 19% finished product. The glass fibers can be up to about 50% by weight and preferably about 35% by weight of the finished product. He Co-binder may be about 10% to about 40% by weight and preferably about 28% by weight of the finished product. Finally, cellulose or cellulose-based material can constitute up to about 50% by weight and preferably about 19% by weight of the finished product. Arranged on one or both outer surfaces of the sound absorbing material may be a front fabric. A preferred front fabric may be constituted by a polyester and rayon and more preferably approximately 70% polyester and 30% rayon, pure polyester or some convenient combination thereof. The front fabric improves the aesthetic appearance while providing resistance to the finished product with the sound absorbing material. The front fabric can be applied to the sound absorbing material with a thermosetting resin or a thermoplastic and can affect the amount of distortion of a poly-film as will be discussed below. However, the front fabric is not essential for practicing the present invention. The present invention may also include at least one layer of porous polyolefin film or poly-film fixed to the sound-absorbing mat, a In order to absorb the lower frequency range that the sound absorbing material can not absorb well. The poly-film typically acts as a barrier to high frequency sound. The porous nature of the poly-film of the present invention allows the poly-film to act as an absorber for low frequency sound, however it allows a wide range of higher frequency sounds to pass to the absorbent material where the Previous poly-film laminates. The poly-film can be a thermoset plastic such that the poly-film is thermally bonded to the acoustic insulation mat. Alternatively, the poly-film can be applied to the acoustic insulation mat with the use of resins, copolymers, polyesters and other thermoplastic materials. The poly-film preferably consists of a polyolefin, particularly a polypropylene or polyethylene and should be located between the sound source and the acoustic insulation mat, so that the film resonates against the absorbent material to destroy the acoustic energy of the sound of low frequency. The poly-film preferably has a plurality of spaced acoustic through-flow openings, which allow high-frequency sounds to pass through and be absorbed by the mat. acoustic isolation. The surface area of the acoustic through-flow opening as a minimum may be between 0.25% and 50.0%. Before molding, the acoustic through-flow openings may be circular, square, or any other pre-selected geometrical shape including grooves or slits. And when molding, the poly-film comprises multiple openings of random shape having various shapes, sizes and areas that allow the film to absorb low frequency sounds and allow high frequency sounds to pass and be absorbed by the sound absorbing material. In operation, the poly-film absorbs low frequency sounds by resonating and destroying acoustic energy while reflecting some high frequency sounds. Other sounds in the high frequency range that pass through the acoustic through-flow openings are absorbed by the acoustic insulation mat. The front fabric material can also be used with the porous polyolefin film equally. All of the above stated objectives will be understood as exemplary only and many more objectives of the invention may be extracted from the present disclosure. Therefore, no limiting interpretation of the objectives should be understood without read further the entire specification, claims and drawings included here. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic flow diagram of the manufacturing process of the insulation product of the present invention; Figure 2 shows a perspective view of a sound absorbing material of the present invention, including an amplified representation of the homogenous mixed matrix of the present invention; Figure 3 shows a side sectional view of the sound absorbing material of Figure 2, having a front fabric located on its outer surfaces; and Figure 4 shows a perspective view of a sound absorbing material having a poly-film connected. DETAILED DESCRIPTION OF THE PREFERRED MODALITY In accordance with the present invention, as illustrated in Figure 2, a sound absorbing material 10 is provided, which has at least one front surface and one rear surface in either a molded or lining form. pipeline. • The sound absorbing material 10 has a homogenous mixed matrix of first organic fibers 12 and second inorganic fibers 14. The The sound absorbing material 10 can vary in weight and thickness in order to vary the frequency absorption characteristics and can be of a pre-selected size and shape. In one embodiment of the present invention, the sound absorbing material 10 will be from about 2 mm to about 155 mm in thickness with a previously selected size and shape. The density of the sound absorbing material can be in the range from about 12,013.85 to 640,738.5 g / m3 (about .75 to about 40 pounds per cubic foot (lbs / ft3)). The first organic fibers 12 of the mixed matrix can be polyester. The polyester fibers 12 can generally have a length of between about 5 millimeters (mm) and about 60 millimeters (mm) and are between about 1.2 to 15 denier in diameter. In addition, the polyester fibers 12 may comprise up to about 70% of the finished product and preferably about 19% by weight of the finished sound absorbing material or product. Polyester 12 can be virgin polyester can be recycled from other industrial uses. For example, if much of a polyester product is made that does not meet the specification and should be discarded, this Polyester product can be processed and used in the present invention. In accordance with the present invention, a second inorganic fiber 14 may not be included in the mixed matrix. The second inorganic fibers 14 can be glass fibers such as rotating glass fibers, flame attenuated glass fibers or according to a present embodiment, textile glass fibers. The textile glass fibers 14 can be from about 2 mm to about 130 mm in length and more than 5 microns in diameter. And, although it is within the scope of this invention to use glass fibers that are rotary or flame attenuated, it is preferable to use textile glass fibers, which are less irritating, more economical and therefore preferred in a plurality of applications including for example the automotive industry. More particularly, the great length of the glass fibers compared to flame-attenuated or rotating glass fibers results in a sound-absorbing material that can be bent without breaking, is less brittle and in general is more durable. The textile glass fibers 14 of the present invention may comprise up to about 50% by weight of the finished product, preferably about 35% by weight of the sound absorbing material 10. The polyester fibers at least 12, and preferably the polyester fibers 12 and the textile glass fibers 14 of the present invention are further combined with a thermoset resin 16. The thermosetting resin 16 of the present invention includes phenolic resin, particularly phenol-formaldehyde and more particularly a phenolic powder resin. The amount of the thermosetting resin will be from about 10 to about 40%, preferably about 28%, of finished product. However, other terpene resins that may be employed include for example epoxy resins, vinyl esters, urethane silicones and others. In addition, these resins may be in the form of powder, latex, oil-based or solvent-based form or they may be liquid polymers. The mixed matrix further comprises fibrous cellulose 18 which is low density but provides increased acoustic performance to the sound absorbing material. Since fibrous cellulose 18 is pulp based it has low cost compared to other fiber reinforcements. Additionally, fibrous cellulose 18 can be mixed with kaolin clay to inhibit moisture absorption. Kaolin clay can be up to about 15% of the cellulose mixture by weight. This is a highly desirable feature since the absorption of moisture can lead to ú and foul odors inside the cabin of a car. Preferably, fibrous cellulose-based material 18 has an average diameter of about 0.03 mm and an average length of about 0.08 mm. However, these values may vary if certain characteristics are more desirable than others. In addition, boric acid or some other suitable compound having both antifungal and bacterial growth properties as well as flame retardant properties can be employed. Now with reference to Figure 1, in the manufacture of a product of the present invention, first and second storage hoppers 30, 32 dose or feed the polyester 12 and textile glass fibers 14 respectively onto a first conveyor belt 34 in the form of an uncured mat. The polyester 12 and the glass fibers 14 are fed at a rate generally of about 113.4 to 907.2 kg (250 to 2000 pounds) per hour from the storage hoppers 30, 32. A mixing-selector apparatus can be used to mix and disperse or separate the strands of polyester 12 and glass fibers 14. Many devices or apparatuses are known in the art for separating and dispersing the filaments in a fiber and mixing different fibers such as polyester and glass fibers, producing a uniformly distributed mixture of ingredients and said product will not be discussed further here. However, this stage is not essential at this point in the manufacturing process. Next, third and fourth storage hoppers 36, 38 feed thermo-fixed resins 16 and fibrous cellulose 18 onto the polyester mat 12 and glass fibers 14. The thermoset resin 16 can be fed at a rate of about 29.48 to 408.2 kg ' (approximately 65 to approximately 900 pounds) per hour. The cellulose can be fed at a rate of about 4.54 to about 453.9 kg (about 10 to about 1000 pounds per hour). Next, the fiber-binder-cellulose mixture is transported to a mixing-collecting apparatus 44 having a forming hood 42 where further mixing occurs. A mixer-picker apparatus is used to mix and disperse the strands of polyester 12, glass fibers 14, thermoset resin 16 and cellulose 18. The high speed rotary device facilitates uniform mixing of the material components absorbent sound. For example, a high speed cylindrical roller having hardened steel teeth that open the fibers and also mix the cellulose and resin can be employed. Also, various known means can be used to facilitate mixing and dispersion of the first and second man-made fibers, cellulose and thermosetting resin used. In the present method, the mixing device 44 can release the man-made fibers 12, 14, the thermosetting resin 16 and the cellulose 18 into the air. An area or chain conveyor forming mat 40 preferably has a suction pressure or negative applied which generally pulls the fibers 12, 14, the resin 16 and the cellulose 18 against the mat forming chain conveyor 40, which forms an uncured, uncured fiber-binder-cell mat. Alternatively, a mat forming area can be understood to include the mat forming roller or other mat forming apparatus. The mat 10 is generally up to about 70% by weight polyester, preferably about 19%, up to about 50% by weight of textile glass fibers, preferably about 35%, between about 10 to 40% by weight. binder, preferably about 28% of the thermo-fixed resin and up to about 50% by weight of material based on cellulose, preferably about 19%. Nevertheless, the present invention can also be formed as a mixture of polyester, a cellulose-based material, and a co-binder without glass fibers. Once the uncured uniform mat 10 is formed, the mat is transported to a curing oven 50. Within the curing oven 50, the uncured mat 10 is subjected to sufficient heat to at least cure and set a desired ratio of the thermosetting resin 16. In other words, the mat can be semi-cured or fully cured. In the production of cured mat or duct liner 10, the furnace 50 may have an operating temperature of between about 204.4 and 315.6 ° C (400 and 600 ° F). The temperature depends on the thickness and gram weight of the mat that is produced and typically the mat remains in an oven for 1 to 4 minutes in order to produce duct lining. In the production of a semi-cured mat 10, ready for further molding, the temperature in the furnace may be in the range from 93.3 to 148.9 ° C (200 to 300 ° F) and the curing time may be approximately 1 to 3 minutes in such a way that the phenolic resin only partially sets. Now with reference to Figure 3, according to a first alternative, a front fabric 20 can applied to one or both of the outer surfaces of the sound-absorbing material or uncured mat 10. The front fabric 20 may be comprised of approximately polyester and rayon, pure polyester, or various other known combinations. A preferred front fabric 20 is about 70% polyester and about 30% rayon. The front fabric 20 improves the aesthetic appearance while providing resistance to the finished product with sound absorbing material. The front fabric 20 can be applied to the sound absorbing material with a thermosetting resin or a thermoplastic and can affect the amount of distortion of a porous poly-film 24 described below, which can also be applied. However, the front fabric 20 is not essential to practice of the present invention. According to a second alternative embodiment, a porous polyolefin film 72 can be located in the uncured sound absorbing material 10 which forms a laminate 70, as illustrated in Figure 4. In a preferred embodiment, the poly-film 72 is located between a sound source and the sound absorbing material 10. The porous poly-film 72 has at least one acoustic through-flow opening 74 and preferably a plurality of openings 74 comprising between about 0.25% and 50.0% of total surface area of the poly-film 72. The plurality of acoustic through-openings 74 may be in a spaced configuration and the initial openings 74 before molding, may be a plurality of shapes eg square, circular or slots. The poly-film 72 may vary in thickness in the range from about .00508 to about .508 mm (.2 to 20 mils) and may also vary in weight to absorb various frequency ranges. The porous poly-film 72 may be between about 0.4 to 40.0% by weight of the finished product. According to a second alternative embodiment of the present invention, the porous poly-film 72 absorbs frequencies below about 2500 Hz better than the sound absorbing material 10 alone and when used in combination with the sound absorbing material 10, the poly -film 72 raises the noise reduction coefficient of total noise. The openings 74 of the porous poly-film 72 play an important role in absorbing a wide range of low frequencies instead of a very specific limited range. To form the porous poly-film 72, a plurality of spaced openings 74 are placed in the polyolefin film 72. The openings 74 as discussed previously they may be from about .10 to about 25.4 square millimeters (mm2) and may be arranged in a spaced configuration. The porous poly-film 72 is stretched over the sound absorbing material 10 with the application of heat varying non-uniformly to the density of the poly-film 72 as the poly-film 72 becomes thinner. Further, stretching the poly-film 72 over the sound absorbing material increases the area of at least one opening 74 that grows in directions for stress relief. In the second alternate embodiment of the present invention, it is also convenient to use a front fabric 20. The front fabric 20 helps maintain the laminate 70 of the sound absorbing material 10 and the poly-film 72, once the laminate 70 is formed. manufactures and molds as well as provides an aesthetically pleasing appearance. Again with reference to Figure 1, the sound absorbed or cured material 10 or rolled 70 leaving the curing oven can pass through a cooling chamber 50 and then through a router 52, where the router, slot the finished product into sections of a width and length pre-selected The product is then transferred by conveyor for storage for future use. In the molding process, the sound absorbing material 10 with or without the front fabric 20 or the laminate 70 will be completely cured and will set in a pre-selected shape and thickness with a molding unit 60. Various types of molds can be employed with the present invention including but not limited to rotary molds, or double shuttle molds, shuttleless molds, and roller-loader molds. These molds are generally displaced by hydraulic or air cylinders that generate between 6.89 and 689 kPa (1 and 100 pounds per square inch (psi)) of molding pressure. Typically, the molding time takes between 45 and 150 seconds with molding temperatures of between about 190.6 and 232.2 ° C (375 and 450 ° F) which is a function of the density and weight of the sound absorbing material 10. The absorbent material Sound 10 or molding laminate 70 can be formed in either a hot molding or a cold molding process. In a hot-casting process, heat can be provided to the mold cavity in a plurality of methods including hot forced air that is provided by gas combustion, electric heat, heating infrared, radiant heating or heated thermal fluids. The mold temperature should be higher than the desired activation temperature, to take into account heat loss of the mold and the like. The activation temperature of the thermosetting resin can be between approximately 48.9 and 260 ° C (120 and 500 ° F). Once the semi-cured sound absorbing material is placed in the mold cavity, the mold press applies pressure. In the cold molding process, the sound absorbing material 10 can be produced with a thermosetting resin and a thermoplastic, where for example the thermoplastic is polyester. The uncured sound absorbing material is heated to an activation temperature between approximately 48.9 and 260 ° C (120 and 500 ° F). Next, the rolling elements are placed in a cooled mold which reduces the temperature of the sound absorbing mat below the activation temperature of the thermoplastic. The mold can be cooled by ambient air, by water or by a cooling system. Within the cooled mold, pressure is applied in an amount in the range of about 6.89 to 689 kPa (about 1 to 100 pounds per square inch). After cold molding or hot molding, the laminate 10 can be cut to Any size and shape pre-selected. The cold-hot-molding processes described above can be repeated for a sound-absorbing material formed with a front fabric 20 and a poly-film 72. Although only one preferred embodiment has been shown and described, it is apparent that those products which incorporating modifications and variations of the preferred embodiment will be apparent to those skilled in the art and therefore the preferred embodiment described will not be considered limited in this manner.

Claims (54)

1. CLAIMS 1. A sound-absorbing material, characterized in that it comprises organic man-made fibers, and inorganic man-made fibers; a co-binder; and a cellulose material; organic man-made fibers, inorganic man-made fibers, co-binder and cellulose material define a homogeneous, sound-absorbing material.
2. 2. The sound-absorbing material according to claim 1, characterized in that the organic man-made fibers are polyester.
3. 3. The sound-absorbing material according to claim 2, characterized in that the polyester fibers are between approximately 5 millimeters and 60 millimeters in length.
4. 4. The sound absorbing material, according to claim 2, characterized in that the polyester is virgin polyester.
5. 5. The sound absorbing material, according to claim 2, characterized in that the polyester is recycled polyester.
6. 6. The sound absorbing material, according to claim 1, characterized in that organic man-made fibers constitute up to about 70% by weight of the sound absorbing material.
7. The sound-absorbing material according to claim 5, characterized in that the organic man-made fibers are approximately 19% by weight of the sound-absorbing material.
8. 8. The sound-absorbing material, according to claim 2, characterized in that the polyester is between about 1.2 and 15 denier.
9. 9. The sound-absorbing material according to claim 1, characterized in that the inorganic man-made fibers are glass fibers.
10. 10. The sound absorbing material according to claim 9, characterized in that the glass fibers are rotating glass fibers having an average diameter of between about 4 and 8 microns.
11. 11. The sound-absorbing material according to claim 9, characterized in that the glass fibers are glass fibers attenuated with flame, having an average diameter between about 4 and 8 microns.
12. 12. The sound absorbing material, according to claim 9, characterized in that the glass fibers are textile glass fibers.
13. 13. The sound-absorbing material according to claim 9, characterized in that the glass fibers are up to 50% by weight of the sound absorbing material.
14. The sound-absorbing material according to claim 13, characterized in that the glass fibers are approximately 35% by weight of the sound absorbing material.
15. 15. The sound-absorbing material according to claim 9, characterized in that the glass fibers are between about 12 and 130 millimeters in length and a diameter between about 5 microns and 12 microns.
16. 16. The sound absorbing material according to claim 1, characterized in that the co-binder is between about 10% to about 40% by weight of the sound absorbing material.
17. 17. The sound-absorbing material according to claim 16, characterized in that the co-binder is approximately 28% by weight of the sound absorbing material.
18. 18. The sound absorbing material according to claim 16, characterized in that the co-binder is a thermosetting resin.
19. 19. The sound-absorbing material according to claim 18, characterized in that the thermosetting resin is a phenolic resin.
20. 20. The sound absorbing material, according to claim 19, characterized in that the phenolic resin is phenol formaldehyde.
21. 21. The sound absorbing material, according to claim 16, characterized in that the co-binder selected from the group consisting of epoxy resin, vinyl esters, urethane silicones, interlaxable plastic polymers, interlacing rubber polymers, powder, latex, oil base, solvent base and liquid polymer.
22. 22. The sound absorbing material according to claim 1, characterized in that the cellulose material is less than about 50% by weight of the sound absorbing material.
23. 23. The sound-absorbing material according to claim 22, characterized in that the cellulose material is about 19% by weight of the sound absorbing material.
24. 24. The sound absorbing material, according to claim 1, characterized in that the cellulose material contains about 15% by weight of the kaolin clay.
25. 25. The sound absorbing material according to claim 23, characterized in that the cellulose material is defined by a plurality of strands having a diameter of about .03 and about .08 millimeter in length.
26. 26. The sound-absorbing material according to claim 1, characterized in that it also comprises a fixed poly-film layer.
27. 27. The sound-absorbing material according to claim 26, characterized in that the poly-film layer is a porous polyolefin layer.
28. 28. The sound absorbing material according to claim 1, characterized in that it also comprises a pre-selected amount of boric acid.
29. 29. The sound absorbing material according to claim 1, characterized in that it also comprises a front or face fabric.
30. 30. The sound absorbing material, according to claim 29, characterized in that the front fabric is formed of polyester.
31. 31. The sound-absorbing material, according to claim 29, characterized in that the front fabric is formed of about 70% polyester and about 30% rayon.
32. 32. A sound absorbing material, characterized in that it comprises a homogeneous mixture of: a plurality of polyester fibers; a plurality of textile glass fibers; a thermo-fixed co-binder; a plurality of cellulose fiber materials; and at least one layer of a porous poly-film.
33. 33. The sound-absorbing material according to claim 32, characterized in that the porous poly-film is a thermo-fixed plastic.
34. 34. The sound absorbing material according to claim 32, characterized in that the porous poly-film is formed of polypropylene.
35. 35. The sound-absorbing material according to claim 32, characterized in that the porous poly-film is formed of polyethylene.
36. 36. The sound-absorbing material according to claim 32, characterized in that the porous poly-film has at least one acoustic through-flow opening dimensioned between approximately .25 and 50% of the surface area of the poly-film.
37. 37. A sound absorbing material, characterized in that it comprises a homogeneous mixture that includes: a plurality of polyester fibers; a plurality of textile glass fibers; a thermo-fixed coaglutinante; a plurality of cellulose fiber materials; a pre-selected amount of boric acid; and at least one layer of porous polyolefin film.
38. 38. Process for producing a sound absorbing material, characterized in that it comprises the steps of: dosing organic and inorganic fibers made by man, on a conveyor belt and forming an uncured mat; dosing a co-binder and fibrous cellulose on the conveyor belt and the uncured mat; transporting the uncured mat into a mixing apparatus and forming an uncured mixed mat; transport the uncured mixed mat in a curing oven.
39. 39. The process for producing a sound absorbing material according to claim 38, characterized in that the dosage of the organic and inorganic fibers made by man to a speed between approximately 113.4 and 907.18 kg (250 and 2000 pounds) per hour.
40. 40. Process for producing a sound absorbing material according to claim 38, characterized in that the co-binder is dosed at a rate between about 29.48 and 408.23 kg (65 and about 900 pounds) per hour.
41. 41. Process for producing a sound absorbing material according to claim 38, characterized in that the cellulose is dosed at an expense between about 4.54 and 453.6 kg (10 and 1000 pounds) per hour.
42. 42. Process for producing a sound absorbing material according to claim 38, characterized in that the curing oven has an operating temperature between about 204.4 and 315.6 ° C (400 and 600 ° F).
43. 43. Process for producing a sound absorbing material according to claim 38, characterized in that the curing oven has an operating temperature between about 93.3 and 148.9 ° C (200 and 300 ° F).
44. 44. An improved sound absorbing material, characterized in that it comprises a mixed matrix of polyester fibers and glass fibers textile; the matrix further includes a co-binder mixed with the glass and polyester fibers and a fibrous cellulose.
45. 45. The sound absorbing material, according to claim 44, characterized in that the matrix is a material for duct lining.
46. 46. The sound-absorbing material, according to claim 44, characterized in that the matrix is a molded material.
47. 47. The sound-absorbing material according to claim 44, characterized in that the sound-absorbing material has a thickness between 2 and 150 millimeters.
48. 48. The sound absorbing material, according to claim 44, characterized in that the polyester is recycled.
49. 49. The sound-absorbing material according to claim 44, characterized in that the glass fibers have a length between 12 and 130 millimeters.
50. 50. The sound-absorbing material according to claim 44, characterized in that the glass fibers are textile glass fibers having an approximate diameter of 5 microns.
51. 51. Process for producing a sound absorbing material, characterized in that it comprises the steps of: (a) forming an uncured mat of polyester fibers and textile glass fibers dosed on a chain conveyor having a negative pressure; (b) dosing a pre-selected amount of thermo-fixed resin and fibrous cellulose onto the uncured mat; (c) mixing the glass fiber and polyester with a mixing-collecting apparatus; (d) transporting the being through a curing oven to adjust a desired proportion of thermo-fixed resin and form at least one mat partially cured; (e) cool the mat; (f) placing the mat to a desired size; and (g) molding the mat to a desired shape.
52. 52. The process for producing a sound absorbing material according to claim 51, characterized in that it further comprises the step of applying a porous polyolefin film to at least one side of the cured mat.
53. 53. The process for producing a sound absorbing material according to claim 51, characterized in that the molding step is a hot molding process.
54. 54. The process for producing a sound absorbing material in accordance with the claim , characterized in that the molding step is a cold molding process.