MXPA98000206A - Identification of recirculable carpet materials using an infrared man spectrometer - Google Patents

Abstract

The present invention relates to a method and apparatus for use in the recirculation of post-industrial or post-consumer waste carpet or polyamide-6 and / or polyamide-66, which contain waste other than carpet, uses a hand-held portable device that uses spectroscopic principles to accurately and quickly identify waste material (carpet), the spectrometer provided for this task includes a source of infrared radiation to illuminate the waste sample (carpet), a selector to select a predetermined number of lengths of separate wavelengths and a detection system for detecting the reflected radiation within the separated wavelengths, the selector can be either a plate with a plurality of slots corresponding positionally to locations in a scattered beam of light in accordance with the lengths of separate wave or a plurality of filters selected to pass the wavelengths sep plows, the selection of the separated wavelengths can take place before the carpet sample is treated with radiation or can take place by selecting separate wavelengths from the reflected radiation

Description

IDENTIFICATION OF RECIRCULABLE CARPET MATERIALS USING A MANUAL INFRARED SPECTROMETER BACKGROUND OF THE INVENTION Field of the Invention The invention relates to a method and apparatus for identifying post consumer or post industrial waste carpets using an infrared (IR) spectrometer, and more particularly to a method for identifying post consumer or post industrial waste carpets using a hand-held spectrometer (IR) that has an IR radiation source that illuminates the post-consumer or post-industrial waste carpet with IR radiation, a selector to select a predetermined number of discrete radiation wavelengths and a detection system IR to detect the radiation reflected by the post-consumer or post-industrial waste carpet. The invention also relates to a method and an apparatus for identifying materials containing polyamide-6 and / or polyamide-66 using an IR spectrometer held by hand making possible the classification of polyamides.

Description of Related Art The recirculation of post-consumer or post-industrial waste carpet materials requires that post-consumer or post-industrial waste carpet material be classified according to the type of surface fiber used to manufacture the carpet. Throughout this application, repeated reference will be made to "post-consumer waste carpets", which is used as a generic term that includes both post-consumer waste carpet and post-industrial waste carpet and waste streams containing polyamide-6. and polyamide-66. At present, carpets use surface fibers produced from materials such as polyamide-6, polyamide-66, polypropylene, wool, polyester and mixtures of these component products. For a recirculation program to be successful, it must be easy to accurately identify the type of surface fiber used by the carpet. One method to identify carpets is to print a code on the back of the carpet. Unfortunately, although this is the most effective fail-safe method of all possible methods, it requires that carpets have been marked during their manufacture. Therefore, even if the marking began today, this method would not be effective for approximately 10 years due to the expected life of the marked carpet. In addition, this method may not be satisfactory if it is used with adhesive mats, since the backside of the mats with adhesive could be damaged, thus making it difficult to read the identification code. Alternatively, it is possible to identify the type of carpet by detecting the melting point of the surface fiber. This identification method is inadequate because it is not able to separate the polyester and polyamide-66 streams. In addition, mixtures of different types of surface fibers can not be distinguished. Devices that use the melting point of carpet material as a distinctive feature are also deficient, since they generally tend to have a long warm-up time, thus reducing efficiency, and can be dangerous since they necessarily involve the use of hot components. A third way of identifying the type of surface material used on a particular carpet sample is to use a spectroscope. It is well known that many materials can be identified using vibratory spectroscopic techniques such as mid-infrared and near-infrared spectroscopy. In particular, near infrared spectroscopy is a well-known method, e.g., for the classification of bottles. IR spectroscopy can be carried out on transparent materials by analyzing the radiation that passes through the materials, and on substances that are opaque to IR radiation by analyzing the diffuse radiation reflected by the material. To adapt to the common use in optics, this request will sometimes refer to IR radiation as "light". IR spectrometers, both for the near infrared (800-2500 nm) and the medium infrared (2500-25000 nm) scale, are commonly used to identify and quantify materials based on the characteristics of the material that cause it to absorb or reflect particular wavelengths. In many cases, these characteristic frequencies are only slightly different for different materials. Therefore, it is important to use a high spectral resolution spectrometer, especially when trying to distinguish between several materials mixed together. An IR spectrometer generally includes a source that emits radiation on the desired wavelength scale and auxiliary optics such as lenses and mirrors to give the radiation the shape of a beam of suitable shape and dimensions and to guide it along a path of light. As a rule, all the elements that make up the spectrometer are accommodated in a case that is preferably closed to prevent dust from interfering with the components. The light source is positioned to prevent dust from interfering with the components. The light source is preferably placed in a reflector case so that the spectrometer can obtain as much light as possible. The light source is preferably incorporated in the optical case, so that the light comes out from the spectrometer through an optically transparent window to hit the target material. The transparent window may be, for example, glass or high quality quartz, or it may be made of, for example, KBr, KC1, ZnSe, KRSs, CaF2 or MgF2 for the average infrared scale. The beam is directed towards the site on the material that will be examined. The reflected radiation is then collected, formed to have a desired beam geometry and eventually directed over a detection system. This detection system normally includes a detector capable of measuring the intensity of the incident radiation. Many detectors that can be used in the near infrared range include PbS and InGaAs detectors, and detectors that can be used in the mid-infrared range include detectors made of deuterized triglycinsulfate (DTGS). There are several basic types of IR spectrometers. Two types of IR spectrometers are described below. In the first type, discrete wavelengths are selected by passing the reflected radiation through different filters that are only transparent at a particular wavelength scale. In the second type, a beam of reflected IR radiation is scattered, and is allowed to collide on a diode array. Unfortunately, diode arrangements of this nature and having the desired resolution power are very expensive, and the selection of the desired wavelength from the absorbed spectrum must take place at a later stage in the downstream processing equipment, increasing thus the amount of electronic support elements necessary to use the spectrometer. The ratio between the intensity and the wavelength of the light reflected or transmitted from a particular material is called the spectrum. The detector is connected to a processing system that converts the detector signals into a spectral form accessible to the user or to a computer, such as a curve or numerical values. In general, the average and near infrared spectra of the different types of fibers used in carpets differ significantly. However, the spectra of polyamide-6 and polyamide-66 differ only slightly: the average infrared spectrum is completely identical and the near infrared spectrum is only slightly different is the spectral scale of 2000-2500 nm. The quality of identification obtained using a certain spectroscopic system is expressed as the distance Mahalonobis (MD), which is the distance from center to center between the different clusters in relation to the expansion within the clusters. For a proper separation, a minimum MD value of approximately 6 is required, but ideally the value should be more than 10. Unfortunately, although Ghosh and Rogers (Melliand Textilberichte 5, 1988, pgs. 361-364) indicated that the scrutiny spectrometer in their system achieved very good MD results to classify fibers of polyamide-6 and polyamide-66 (MD = 18), the size and price of the scrutiny spectrometer makes this system highly inappropriate to be used in the carpet recirculation business. Ghosh and Rogers also demonstrated that it is possible to identify nylon 6 and nylon 66 fibers used for carpet production using an InfraAlyzer 500C from Bran &Luebbe (formerly Technicon), with a combination of three filters, (2250, 2270 and 2310 nm ) These reported results are also disappointing, since the carpets used have different fiber materials than the new carpets due to wear and contamination, thus complicating their identification. For example, by using these same three filters on one of 113 samples of post-consumer waste carpets, the applicants discovered that the obtainable MD varied between 4 and 1.2, depending on the resolution of the spectrometer. As indicated above, results of this nature are clearly insufficient to discriminate accurately between several carpet samples. Consequently, it has not yet been demonstrated that it is possible to distinguish different types of post-consumer waste carpets using a cheap, small and portable spectrometer based on selected wavelengths. Similarly, although portable and inexpensive spectrometers based on an IR filter are commercially available to carry out specific applications, such as determining the moisture content of various materials, no one has been able to develop a spectrometer supported by hand. that is able to distinguish satisfactorily between different types of materials from the surface of the carpet so that the spectrometer can be used properly in the recirculation of carpets of post consumer waste.

BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a method for reliably analyzing post-consumer waste carpets using an IR spectrometer held in the hand. To do this, the invention uses a hand held spectrometer that is capable of measuring a number of discrete wavelengths with sufficient resolution. In this regard, two spectrometers can be glimpsed with the hand. The first handheld spectrometer is capable of measuring a number of discrete wavelengths with good resolution using a radiation selector that scatters the radiation and selects discrete wavelengths from the scattered radiation using a plate provided with openings in locations which correspond to the positions of the discrete wavelengths in the scattered radiation that will be selected. The second handheld spectrometer is also capable of measuring a number of discrete wavelengths, but uses filters that pass particular selected wavelengths that are optimal for use in the carpet recirculation business. Depending on the application to the spectrometer, the spectra are recorded on the near infrared scale or on the average infrared scale of a series of samples using a high resolution spectrometer. These high-resolution spectra are used to determine the combination of absorptions at different wavelengths that produce enough information to discriminate one polymer from another. In the case of carpet recirculation, for example, one might wish to know without a carpet it is made of polypropylene, polyamide-6, polyamide-66 or polyethylene terephthalate (PET). The absorption of the detector must be compared against a reference material of a known substance. Suitable reference materials for diffusing reflection in the near infrared scale include, for example, small ceramic plates and small Teflon plates. The absorption is calculated as follows:? = l? g (I? (mut? tr) / I? (reference material)), (1) where ^ is the absorption at the wavelength? SAW? is the intensity of light at wavelength? - An analysis based on absorption at different wavelengths is obtained using normal mathematical methods. The analyzes can be used to identify and / or quantify samples with the help of chemometric methods. Chemometric methods of identification are described, for example, in Ghosh et al., Melliand Textilberichte 5 (1988) 361. In order to identify the samples of different types of carpets, a mathematical analysis is made to establish the combination of wavelengths that ensure the best separation between the different materials that will be identified. For a series of used and unused carpets, the spectra can be recorded on the near infrared scale with a resolution of 2 nm. The separation is calculated using a cluster analysis for all possible combinations of, for example, three wavelengths (? L,? 2,? 3). To do this, the values of, for example A - (? 2) -A (? D and A (? 3) -A (? 2) are calculated, where A \ is the absorption at the specified wavelengths When these are plotted on a graph, there appear to be separate clusters for the different materials in different combinations of wavelengths.The quality of separation increases accordingly, since the clusters are better isolated from each other.The optimal separation is achieved by selecting the combination of, for example, three wavelengths in which the Mahalanobis distances between the three clusters (4 different Mahalanobis distances) are maximum.

To separate polyamide-6, polyamide-66, PET and polypropylene, a combination of the 2432, 2452 and 2478 absorptions seems to be optimal. In this way, it is possible to determine what discrete wavelengths should be measured for a particular application to clearly distinguish the different materials with the spectrometer of this invention. Then, using normal optical calculation methods, the locations of the holes in the plate can be easily determined depending on the particular combination of grid, inlet slot, distance from the grid to the plate, etc. A broader and more extensive optimization is carried out mathematically using a technique called "genetic algorithms". In this technique, the full spectrum of several samples is taken using a high quality scanning spectrometer that has a spectral resolution and adequate signal-to-noise ratios. The set of spectra is transformed to simulate spectral resolutions that are worse (e.g., 10 nm, 20 nm, 30 nm and 40 nm), since for devices held with the cheap hand the resolution is lower than for the search-grade spectrometer. In addition, the signal-to-noise ratio and the accuracy of the wavelength selection is less for handheld devices. Therefore, these effects must be included in the wavelength selection procedure. In the optimization procedure of genetic algorithms, the optimization conditions can be defined in any desired way. For example, optimization conditions can be programmed to maximize the MD of polyamide-6 and polyamide-66, maximize the minimum of MD of polyamide-6 to the other types of materials, maximize all the MD's, etc. An experiment was carried out using the technique of genetic algorithms. In the first example, it was chosen to maximize the minimum of the MDs of polyamide-6 to the other types of materials (polyamide-6-polyamide-66, polyamide-6-polypropylene, polyamide-6-PET). The allowed displacements of the selected wavelengths were programmed to be ± 6 nm, the spectral resolution was chosen at 16 nm, the signal to noise ratio was set to 200. Four wavelengths were chosen using these parameters: 2382, 2430, 2452, 2472, which gave the following results: MD of polyamide-6-polyamide-66: 8.2-11.8 MD of polyamide-6-PET: 16.5-22.5 MD of polyamide-6-polypropylene: 8.2-11.9 Next describe the IR spectrometers according to the invention: The first type of IR spectrometer of this invention has been shown to be able to select narrower wavelength scales than the known spectrometers by dispersing the originating radiation. Dispersion in this context means the spatial distribution of the different wavelengths that occur in a beam of radiation. A well-known device useful for causing the scattering of a radiation beam that arrives is a grid. In this first spectrometer, a grid is preferably stationary and has between 100-4000 lines / mm. The reflected or transmitted light converges, with or without the aid of a lens system, so it enters the grid through an input opening that measures between 100 and 1000 microns. At any distance behind the opening, a point in the plane perpendicular to the direction of the radiation corresponds to a particular wavelength. This being the case, a certain desired wavelength can be selected from the spectrum by transmitting or assembling a portion of the spectrum radiation passing through the corresponding location. The grid can be placed in the optical system so that the beam is reflected by the post-consumer waste material. The reflected radiation can be collected, for example, in a number of appropriately positioned detectors. A problem in this case is the minimum dimension of the available detectors, which makes it possible for adjacent wavelengths to be observed by the detector, as well as the desired wavelength. In a preferred embodiment of the IR spectrometer of this invention, this problem is solved by selecting a discrete wavelength with a plate that is opaque to IR radiation, positioned between the source and the detection system, so that no radiation can reach the system of detection more than through the openings in the plate. The plate is provided with openings in locations corresponding to the positions of the discrete wavelengths in the scattered radiation that will be selected. The openings in the plate can be made very small, in any case substantially smaller than the minimum dimensions of the available detectors. The openings in the plate can also be positioned with great precision. In this way, it is possible to accurately select the desired wavelengths from the scattered radiation beam with high resolution. In this mode, the intensities of the different wavelengths can be measured individually by placing a detector behind each opening in the plate or by using a plate and detector that move in mutual relation so that the detector can be placed in series behind the detector. each opening of the plate. In this case, the problems associated with a finite detector dimension do not arise because the location and size of the openings independently determine the selection and resolution of the spectrometer wavelength. Another possibility, which provides greater flexibility in the design, is to connect a light conductor to each of the openings in the plate and transport the radiation to the detection system through these conductors. In this case, separate sensors can again be used, or the individual light conductors can also be connected to, for example, a rotating system or a sliding system, whereby the individual conductors can be arranged individually in front of a single detector. Alternatively, the detector can be movable so that it can be placed in front of several stationary light conductors. The movement of the detector or of the sliding or rotating system is preferably controlled by a computer system that is also capable of processing the measurement results. The results, for example, can be presented online on a visual presenter. In this way, in a separation system for material flow, an operator can intervene based on the displayed value. In the same way, the computer can be connected to, and control a mechanical system that is downstream. The results of the measurement can also be used to control a production process. In another embodiment, the grid can be placed in the optical system before the radiation beam hits the test material. In this case, the scattered light is passed through a plate with slots and in this way the selected light with the desired wavelengths is passed by means of light conductors on the material. The amount of reflected light is then measured to obtain light that can be analyzed to determine the type of material. In this case, each plate opening allows light of a desired wavelength to pass through. The passed light is transmitted by a light conductor having one end positioned adjacent the slot in the plate and the other end positioned so that the outgoing radiation can be directed to the material. Directing the outgoing radiation can be achieved, for example, by terminating the ends of the light conductors in a rotating system which, when rotated, allows a particular light conductor to irradiate the material by optically isolating the other conductors of the material at the same time. By causing the rotary system to successively assume a number of different positions, for example, using a stepped motor, the material can be irradiated successively with different wavelengths and the intensity of the wavelengths can be measured individually. A lens system can optionally be provided to ensure that the material to be examined is properly illuminated. The light conductors suitable for use in this system are the optical fibers that are transparent to the infrared scale between 1000-2000 nm. Quality glass fibers with a low SiOH content are suitable for the infrared scale between 2000-2500 nm. Chalcogenide or Ag-halide fibers are suitable for the average infrared scale. Other optical fibers that are transparent in the desired wavelength scales can also be used. The diameter of these fibers is preferably between 100 and 1000 microns. The positions of the openings are calculated from the desired wavelengths, the geometry of the spectrometer and the characteristics of the grid. The desired wavelengths depend on the materials that will be detected and separated, which determine the location of the holes in the plate. The positions of the holes can be determined using cluster analysis, as described above. The second type of IR spectrometer of this invention uses a combination of filters placed on a filter wheel that is driven at high speed (10-200 Hz). Using this mode, the sample is illuminated using a set of lamps and the diffuse reflected light is collected using a lens. The light is then directed through the filter wheel and detected using a PbS or InGaAs detector. The use of a filter wheel has several unique advantages. For example, since the filter wheel blocks the light beam four times during each rotation, the dark current of the detector can be sampled frequently and used to correct for changes in temperature and other fluctuations of the detector. The collection angle for this system should be kept small, preferably less than 5o, to maintain the spectral resolution of the filter below 20 nm. The signals from the detector are processed using an integrated microprocessor. Alternatively, the filters can be used to select predetermined wavelengths that come from an infrared radiation source before the radiation hits the post consumer waste carpet sample. In this system, a filter wheel is rotated to allow infrared radiation having a predetermined wavelength scale to exit the spectrometer. The emitted light is reflected by the post consumer waste carpet sample, and then detected by the detector. Instead of using a filter wheel, it may also be possible to use selectable optical acoustic filters (AOTF). AOTF devices are based on acousto-optic effects in which the optical refractive index of a medium is altered using ultrasound (see Focus World Laser, May 1992). Essentially, AOTF devices are crystals that receive a beam of light and transmit selected wavelengths of the incident light beam based on a frequency of an acoustic input signal. With the use of an AOTF device, wavelengths can be selected by adjusting an ultrasound frequency applied to the AOTF device, thus eliminating the moving parts associated with a filter wheel.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiments of the present invention will now be described more specifically with reference to the accompanying drawings, in which: Figure 1 is a side view of a hand held spectrometer according to a first embodiment of this invention; Figure 2 is a side view of a hand held spectrometer according to a second embodiment of this invention; Figure 3 is a side view of a hand held spectrometer according to a third embodiment of this invention; Figure 4 is a side view of a hand held spectrometer according to a fourth embodiment of this invention; Figure 5 is a side view of a hand held spectrometer according to a fifth embodiment of this invention; Figure 6 is a filter wheel that is used with the spectrometer held with the hand illustrated in Figure 5; Y Figure 7 is a side view of a hand held spectrometer according to a sixth embodiment of this invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The boundaries of the radiation beams are shown in the figures with dot and dash lines, and the individual light rays are indicated by dotted lines. In Figure 1, the light source 1 is placed in a reflector case 2. The light emitted from the light source 1 is directed onto a material 3 to be examined. The reflected radiation converges on a lens 4, where the central beam hits a grid 6 through an input slot 5. The radiation is scattered by the grid 6 at different wavelengths. A plate 7 is placed in the scattered radiation beam, and has openings 8 corresponding to selected wavelength positions within the spectrum. The first ends of the light conductors 9 are installed in the openings 8 of the plate 7. The other ends of the light conductors are each inserted into an opening of the selector plate 10, the light conductors concluding on a surface 11. on the plate. The selector plate 10 can be moved with a stepped motor (not shown) so that the detector 12 only observes the light coming from a particular light conductor through an aperture 13 in an opaque plate 14 inserted between the selector plate 10 and the detector 12. The detector 12 is connected to a processing system (not shown). In figure 2, a light beam 201 is placed in a reflector case 202. The light converges on the lens 204, so it strikes a grid 206 through an input slot 205. The radiation is scattered by the grid at different wavelengths. A plate 207 is placed in the scattered radiation beam, which is provided with apertures 208 corresponding positionally at selected wavelengths. The first ends of the light conductors 209 are installed in the openings 208 of the plate 207. The other ends of the light conductors are each inserted into the selector plate 210, the light conductors concluding on the surface 211 of the plate. 210. An opaque plate 214 is provided behind this selector plate with an opening 213. This plate 214 can be moved with a stepped motor (not shown) so that only light coming from a particular light conductor can pass through. of the opening 213. The light passing through this opening 213 diverges in a lens 216, after which the diverged radiation strikes the material 203 to be examined. The radiation reflected by the material converges on the lens 217 and then hits the detector 212. The detector 212 is connected to a processing system (not shown). The IR spectrometer of the invention can be made very compact for easy handling. The IR spectrometer can be used advantageously in the field of recirculation of plastic materials in general, as long as the specific wavelengths are selected as appropriate for the characteristics of the determined material. Figures 3 and 4 are identical to Figures 1 and 2, respectively, except that they illustrate the situation in which light passing through the sample material is collected and evaluated in the spectrometer. Figure 5 shows a second embodiment of a device that can be used to determine the spectral qualities of a post consumer waste carpet. In Figure 5, a spectrometer 100 has a rotating filter wheel 102 which is driven by a motor 104. The light is provided by one or more lamps 106 on one side of the spectrometer 100 so that it collides on a post carpet sample of waste. consumer 108. The light reflected by the sample 108 is picked up by a lens 110, directed through the rotary filter wheel 102 and detected by a PbS or InGaAs detector 112. In figure 6 an example of a rotating wheel is shown. rotary filter 102. In this example, four filters 114 (AD) are provided on the rotary filter wheel 102. A hole 116 is provided at the center of the rotary filter wheel 102 to receive a drive shaft 118 extending from the motor 104. During operation, the motor 104 causes the rotary filter wheel 102 to rotate, so that the light passing through the lens 110 is filtered according to the specific qualities possessed by the filters 1. 14. Detector 112 detects filtered light and provides signals to an electronic circuit 120 that outputs the result. Figure 7 is another example of a spectrometer 100 that uses a rotary filter wheel 102, except that the light is filtered before it impinges on the post consumer waste carpet sample 108. As shown in Figure 7, a source of light 106 produces infrared radiation which is filtered by a rotating filter system 102, 104, 118. The filter passes predetermined wavelengths leaving the spectrometer housing by means of the optics 122. After leaving the spectrometer housing, the lengths predetermined waveforms collide on the post consumer waste carpet sample 108 and are reflected by the post consumer waste carpet sample 108. One or more detectors 112 detect the reflected light and send a signal to an electronic circuit 120 that outputs the result . Although this example has illustrated optics that emit light from only one side of the spectrometer, the light that passes through the filter can be divided alternately and exit the spectrometer at several locations. It is understood that many other modifications will be apparent and can be readily made by those skilled in the art without departing from the scope and spirit of this invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the description set forth hereinbefore, but instead that the claims be considered to encompass all patentable novelty characteristics that reside in the present invention, including all the features that would be treated as equivalents thereof by those skilled in the art to which this invention pertains.

Claims (24)

NOV OF THE INVENTION CLAIMS

1. - A hand-held infrared spectrometer for use in the analysis of post-consumer or post-industrial waste carpets, or non-carpet waste containing polyamide-6 and / or polyamide-66, comprising: a source of infrared radiation to illuminate the waste (carpet) with infrared radiation; a selector to select a number of discrete wavelengths that come from the infrared radiation reflected by the waste (carpet), to obtain a Mahalanobis distance of at least 6; and an infrared detection system for detecting selected discrete wavelengths.

2. A hand-held infrared spectrometer according to claim 1, wherein the selector comprises a dispersion device that disperses the radiation and a discrete wavelength selector that selects the discrete wavelengths that come from the scattered radiation.

3. A hand-held infrared spectrometer according to claim 1, wherein the selector comprises a filter system having a plurality of filters for transmitting only predetermined radiation wavelengths.

4. - A hand-held infrared spectrometer for use in the analysis of post-consumer or post-industrial waste carpets, or non-carpet waste containing polyamide-6 and / or polyamide-66, comprising: a source of infrared radiation to irradiate infrared radiation towards a waste sample (carpet); a radiation selector that selects a plurality of discrete wavelengths, said radiation selector comprising a scattering device that disperses the radiation and a discrete wavelength selector that selects the discrete wavelengths that come from the scattered radiation; and a detection system that detects discrete wavelengths.

5. A hand-held infrared spectrometer according to claim 4, wherein the radiation is scattered and the selected wavelengths are selected before the radiation hits the waste sample (carpet).

6. A hand-held infrared spectrometer according to claim 4, wherein the radiation is scattered and the selected wavelengths are selected after the radiation hits the waste sample (carpet). 7.- A hand-held infrared spectrometer for use in the analysis of post-consumer or post-industrial waste carpets, or non-carpet waste containing polyamide-6 and / or polyamide-66, comprising: source of infrared radiation to irradiate infrared radiation on a waste sample (carpet); a radiation selector that selects a plurality of discrete wavelengths that come from the radiation reflected by the waste sample (carpet), said radiation selector comprising a scattering device that scatters the reflected radiation, and a wavelength selector discrete that selects the discrete wavelengths that come from the scattered radiation; and a detection system that detects discrete wavelengths. 8. A hand-held infrared spectrometer according to claim 7, wherein said discrete wavelength selector comprises a plate provided with openings in locations corresponding to the positions of the discrete wavelengths in the scattered radiation said plate being opaque to the IR radiation and being placed between the source and the detection system so that the radiation can not reach the detection system, except through said openings in said plate. 9. A hand-held infrared spectrometer according to claim 8, wherein said detection system comprises several detectors, one of each of said detectors being provided behind a respective opening in said plate. 10. A hand-held infrared spectrometer according to claim 8, wherein said detection system comprises a detector that can be arranged behind more than one of said openings in said plate. 11. A hand-held infrared spectrometer according to claim 8, further comprising a light-conducting system, said light-conducting system having a plurality of light conductors, each of said light conductors being connected to a of said openings in said plate to transport the light passing through said opening in said plate towards said detection system. 12. A hand-held infrared spectrometer according to claim 11, wherein said detection system comprises several detectors, and each of said light conductors is connected to one of said detectors. 13. A hand held infrared spectrometer according to claim 11, wherein said detection system and the light conductors move in mutual relation so that said light conductors can transport light individually to said detection system. 14.- A hand-held infrared spectrometer for use in the analysis of post-consumer or post-industrial waste carpets, or non-carpet waste containing polyamide-6 and / or polyamide-66, comprising: source of infrared radiation to irradiate infrared radiation on a waste sample (carpet); a filter system comprising a plurality of filters for transmitting only predetermined radiation wavelengths reflected with a collection angle of less than 5o; and a detection system that detects the radiation transmitted by the filter system. 15. A hand held infrared spectrometer according to claim 14, wherein said source of infrared radiation radiates infrared radiation onto a waste sample (carpet) and said filter system transmits only predetermined wavelengths of reflected radiation for the waste sample (carpet). 16. A hand-held infrared spectrometer according to claim 14, wherein said filter system transmits only predetermined wavelengths of radiation that will be reflected by the waste sample (carpet). 1

7. A hand-held infrared spectrometer according to claim 14, wherein said filter system employs a rotating filter wheel having three or more filters. 1

8. A hand-held infrared spectrometer according to claim 14, wherein said filter system employs a rotating filter wheel having four filters that pass light having wavelengths of 2382 n ± 20 nm, 2430 nm ± 20 nm, 2452 nm ± 20 nm and 2472 nm ± 20 nm respectively. 1

9. A hand-held infrared spectrometer according to claim 14, wherein said filter system is a selectable optical filter. 20. A method for discriminating between various types of post consumer or post industrial waste carpets or non-carpet waste containing polyamide-6 and / or polyamide-66, comprising the steps of: providing a sustained infrared spectrometer with hand; and using said hand-held infrared spectrometer to determine the type of waste material (carpet). 21. A method for discriminating between various types of post-consumer or post-industrial waste carpets or non-carpet waste containing polyamide-6 and / or polyamide-66, comprising the steps of: providing a sustained infrared spectrometer with hand; irradiating infrared radiation on a waste sample (carpet) from a source of infrared radiation in said infrared spectrometer held by hand; selecting a plurality of discrete wavelengths from the radiation reflected by the waste sample (carpet) using a radiation selector in said hand-held infrared spectrometer, said step of selecting a plurality of discrete wavelengths comprises the sub-step of scattering the reflected radiation using a scattering device and the sub-step of selecting a plurality of discrete wavelengths from the scattered radiation; and detecting the discrete wavelengths with a detector provided in the hand-held infrared spectrometer, thus using said hand-held infrared spectrometer to determine the type of waste material (carpet). 22. A method for discriminating between various types of post-consumer or post-industrial waste carpet or non-carpet waste containing polyamide-6 and / or polyamide-66, comprising the steps of: providing a sustained infrared spectrometer with hand; irradiating infrared radiation having a plurality of wavelengths on a waste sample (carpet) from a source of infrared radiation in said infrared spectrometer held by hand; said plurality of redetermined wavelengths being selected by scattering an infrared radiation beam using a scattering device and selecting a plurality of discrete wavelengths from the scattered radiation; and detecting the discrete wavelengths with a detector provided in the hand-held infrared spectrometer, thus using said hand-held infrared spectrometer to determine the type of waste material (carpet). 23. A method for discriminating between various types of post-consumer or post-industrial waste carpets or non-carpet waste containing polyamide-6 and / or polyamide-66, comprising the steps of: providing a sustained infrared spectrometer with hand; irradiating infrared radiation on a waste sample (carpet) from a source of infrared radiation in said infrared spectrometer held by hand; selecting a plurality of discrete wavelengths from the radiation reflected by the waste sample (carpet) using a radiation selector in said hand-held infrared spectrometer, said step of selecting a plurality of discrete wavelengths comprises the sub-step filtering the reflected radiation to thereby allow radiation of a plurality of predetermined wavelengths to pass to a detector system provided in the infrared spectrometer held by hand; and detecting the discrete wavelengths with a detector provided in the hand-held infrared spectrometer, thus using said hand-held infrared spectrometer to determine the type of waste material (carpet). 24.- A method for discriminating between various types of post consumer or post-industrial waste carpets or non-carpet waste containing polyamide-6 and / or polyamide-66, comprising the steps of: providing a sustained infrared spectrometer with hand; irradiating infrared radiation having a plurality of predetermined wavelengths on a waste sample (carpet) from an infrared radiation source in said infrared spectrometer held by hand; said plurality of predetermined wavelengths being selected by filtering a beam of infrared radiation using a plurality of filters; and detecting the discrete wavelengths with the detector provided in the hand-held infrared spectrometer, thus using said hand-held infrared spectrometer to determine the type of waste material (carpet).