CA1299243C - Method of monitoring production of protective fabric - Google Patents
Method of monitoring production of protective fabricInfo
- Publication number
- CA1299243C CA1299243C CA000578477A CA578477A CA1299243C CA 1299243 C CA1299243 C CA 1299243C CA 000578477 A CA000578477 A CA 000578477A CA 578477 A CA578477 A CA 578477A CA 1299243 C CA1299243 C CA 1299243C
- Authority
- CA
- Canada
- Prior art keywords
- fabric
- charcoal
- chemical
- tracer
- magnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000004744 fabric Substances 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 title claims abstract description 26
- 230000001681 protective effect Effects 0.000 title claims abstract description 8
- 238000012544 monitoring process Methods 0.000 title claims description 15
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 230000005291 magnetic effect Effects 0.000 claims abstract description 41
- 239000003610 charcoal Substances 0.000 claims abstract description 36
- 239000000700 radioactive tracer Substances 0.000 claims abstract description 24
- 239000000126 substance Substances 0.000 claims abstract description 24
- 238000005470 impregnation Methods 0.000 claims abstract description 14
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000002002 slurry Substances 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims description 22
- YDZQQRWRVYGNER-UHFFFAOYSA-N iron;titanium;trihydrate Chemical compound O.O.O.[Ti].[Fe] YDZQQRWRVYGNER-UHFFFAOYSA-N 0.000 claims description 2
- 229910052952 pyrrhotite Inorganic materials 0.000 claims description 2
- 230000004888 barrier function Effects 0.000 claims 2
- 239000007788 liquid Substances 0.000 claims 1
- 238000005303 weighing Methods 0.000 abstract description 2
- 239000007787 solid Substances 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 229910052594 sapphire Inorganic materials 0.000 description 3
- 239000010980 sapphire Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000001066 destructive effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 230000005298 paramagnetic effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
Landscapes
- Treatment Of Fiber Materials (AREA)
Abstract
The quantity of chemical, e.g. charcoal added to fabric used to produce protective clothing for the military is usually determined by the simple expedient of weighing the fabric or swatches thereof before and after impregnation in a charcoal slurry. This method may result in large errors. A simple, effective method of determining the quantity of charcoal or other chemical being incorporated in a fabric base is to add a magnetic tracer, e.g. magnetite to the chemical prior to impregnation, and to measure the magnetic susceptibility of the fabric on a continuous basis immediately following impregnation. If the magnetic tracer is uniformly mixed with the chemical, the direct correlation between magnetic susceptibility and tracer concentration will provide an accurate indication of tracer and consequently chemical concentration in the fabric. When a chemical such as charcoal possesses an inherent magnetic susceptibility, no tracer is required.
Description
lZ~9Z43 This invention relates to a method of monitoring the production of clothing fabric, and in particular to a method of monitoring the production of fabric for use in protective clothing.
When producing protective clothing for the military, a variety of chemicals, e.g. charcoal, latex and flame retardant are applied to the clothing fabric. Typically, application is effected by dipping the fabric in solutions or slurries of the chemicals, and passing the fabric between squeeze rolls to control the quantity of chemical added to the fabric. In the present case, the aim is to control the quantity of charcoal added to the clothing material. The quantity of charcoal incorporated in the fabric must be monitored and controlled in order to ensure that the clothing provides adequate protection.
At present, the quantity of charcoal added to fabric is controlled by two methods, either or both of which may be used at one time. The first method involves the weighing of one hundred meter rolls of material before and after passage through a charcoal bath and squeeze rolls. A figure representing the average concentration of charcoal in the entire roll is obtained from the equation:
wt after impregnation - wt before impregnation x 100 wt before impregnation = % of added material The second method involves the cutting of small pieces of material from the untreated material, and then passing the material through the charcoal bath and between the squeeze rolls. Additional small pieces are cut from the fabric adjacent to the first "cuts" and of identical size.
The quantity of charcoal added to the material is calculated using the above equation.
The above described measuring methods are not without shortcomings. The first method relies on a number of assumptions. Firstly, it must be assumed that the starting material, i.e. the fabric to be impregnated is uniform in terms of weight per unit area. It has been found that the foam laminate pxesently used in protective military clothing may vary in weight from batch to batch. Thus, if the weight of the untreated material is considered to be a constant, then errors in the calculation of the quantity of added charcoal will occur. Other factors can affect the quantity of chemical added to the fabric during each impregnation operation. It has also been found that if all parameters are kept constant, the quantity of added material can increase constantly through an impregnation operation. Thus, even though the average value obtained using the first method is indicative of acceptable material, there could be large areas of fabric which are unacceptable in terms of charcoal content. Such areas would be detected during the more detailed testing of quality control. However, the problem cannot be corrected after the material has been dried and cured.
g~43 For the most part, the above comments are equally applicable to the second method. Taking small samples or templates as representative of an entire roll of material could be extremely misleading, because of the cyclic nature of the adding of the chemical under constant processing conditions and the inherent variations in the base material.
The second method also requires destructive sampling of the base material.
The object of the present invention is to overcome the problems encountered using present measuring techniques by providing a relatively simple, accurate method of determining the quantity of chemical being added to a fabric on a continuous basis.
Accordingly, the present invention relates to a method of monitoring the production of protective clothing fabric of the type including a chemical incorporated therein by impregnation comprising the step of:
(a) monitoring the magnetic susceptibility of the impregnated fabric to determine the quantity of chemical added to the fabric.
In a specific application of the method of the present invention, commercially available magnetic susceptibility measuring instruments are used to monitor the quantity of charcoal being added to protective fabric. The use of a sensor head proximate the path of travel of the material enables continuous, non-destructive monitoring of the ~g~2~3 material. One suitable instrument for this purpose is susceptibility meter available from Sapphire Instruments of Windsor, Ontario. Another, slightly more sensitive instrument used experimentally, but no longer commercially available is the VGF KL-l magnetic susceptibility bridge.
In order to test the method, a magnetic tracer, which in this case was magnetite (Fe304) was uniformly mixed with a regular charcoal slurry in a variety of quantities based on the quantities of charcoal in the slurry. This experiment was intended to determine an acceptable tracer level. Loadings ranged from 0.04 to 20 g/m2 of magnetite on the base fabric. An extremely linear relationship exists between the loading of magnetite and the magnetic susceptibility through in excess of three orders of magnitude.
In addition to the above mentioned experiment, values for three different magnetic susceptibility instruments were obtained to determine the range of tracer loading required to effect reasonable monitoring of charcoal addition.
For a JH-8 susceptibility meter, approximately 3 - 20%, preferably 6% magnetite on a solids basis (1.8 - 11.8, preferably 3.5 parts magnetite per 100 parts by weight charcoal) were required. The Sapphire Instruments device requires cut samples. However, if a sensor head is used, continuous monitoring can be effected. The quantity of tracer required for the Sapphire Instruments equipment was 0.5 to 10%, preferably 1~ magnetite on a solids basis (0.3 - 5.9, preferably 0.6 parts per 100 parts by weight charcoal). The VGF KL-l magnetic susceptibillty bridge also requires cut samples in the absence of a sensor head, and a magnetic tracer in the amount of 0.5 to 10%, preferably 1.7% on a solids basis (0.3 - 5.9, preferably 1 part per 100 parts by weight charcoal).
It will be appreciated that a determination of the correlation between the magnetic susceptibility and the quantity of charcoal or other material being added should be easy to establish. Thus, a direct reading of the quantity of solids being added to the base fabric can be obtained from the magnetic susceptibility instrument. With the continuous monitoring of the quantity of charcoal (or other chemical) being added to the base fabric, the squeeze roll pressure and other parameters can be varied to ensure that the charcoal concentration in the finished product is more or less constant over the entire length thereof.
Due care must be taken during mixing and impregnation of material that no metals capable of attracting the magnetite are used. It is also worth noting that the particle size of the magnetite may have an effect on the magnetic susceptibility of the material.
Another experiment performed using magnetic susceptibility instruments is the measurement of the magnetic susceptibility of a plurality of charcoal impregnated foam samples over a wide range of charcoal concentrations in the ~Z~9;243 absence of magnetic tracer. The tests showed a correlation between the quantity of added charcoal and magnetic susceptibility. However, the magnetic response was weaker than for samples containing magnetite tracer. Unimpregnated material had no measurable magnetic susceptibility. It appears that the charcoal used has an inherent magnetic susceptibility which raises the question of whether the tracer is absolutely necessary. Of course, in the absence of a magnetic tracer, the chemical being added to the base fabric must have an inherent magnetic susceptibility.
While magnetite is the specific magnetic tracer used in the above examples, it will be appreciated that other minerals such as titanomagnetite, ilmenite and pyrrhotite can be used as the magnetic tracer. A tracer such as HgCo(NCS)4, which is a highly paramagnetic complex, could also be used, permitting the use of lower quantities of tracer in the impregnating slurries or solutions.
Thus, there has been described a relatively simple method of monitoring and assisting in the control of the finishing of a fabric, i.e. the addition of a chemical to the fabric to alter the properties thereof.
When producing protective clothing for the military, a variety of chemicals, e.g. charcoal, latex and flame retardant are applied to the clothing fabric. Typically, application is effected by dipping the fabric in solutions or slurries of the chemicals, and passing the fabric between squeeze rolls to control the quantity of chemical added to the fabric. In the present case, the aim is to control the quantity of charcoal added to the clothing material. The quantity of charcoal incorporated in the fabric must be monitored and controlled in order to ensure that the clothing provides adequate protection.
At present, the quantity of charcoal added to fabric is controlled by two methods, either or both of which may be used at one time. The first method involves the weighing of one hundred meter rolls of material before and after passage through a charcoal bath and squeeze rolls. A figure representing the average concentration of charcoal in the entire roll is obtained from the equation:
wt after impregnation - wt before impregnation x 100 wt before impregnation = % of added material The second method involves the cutting of small pieces of material from the untreated material, and then passing the material through the charcoal bath and between the squeeze rolls. Additional small pieces are cut from the fabric adjacent to the first "cuts" and of identical size.
The quantity of charcoal added to the material is calculated using the above equation.
The above described measuring methods are not without shortcomings. The first method relies on a number of assumptions. Firstly, it must be assumed that the starting material, i.e. the fabric to be impregnated is uniform in terms of weight per unit area. It has been found that the foam laminate pxesently used in protective military clothing may vary in weight from batch to batch. Thus, if the weight of the untreated material is considered to be a constant, then errors in the calculation of the quantity of added charcoal will occur. Other factors can affect the quantity of chemical added to the fabric during each impregnation operation. It has also been found that if all parameters are kept constant, the quantity of added material can increase constantly through an impregnation operation. Thus, even though the average value obtained using the first method is indicative of acceptable material, there could be large areas of fabric which are unacceptable in terms of charcoal content. Such areas would be detected during the more detailed testing of quality control. However, the problem cannot be corrected after the material has been dried and cured.
g~43 For the most part, the above comments are equally applicable to the second method. Taking small samples or templates as representative of an entire roll of material could be extremely misleading, because of the cyclic nature of the adding of the chemical under constant processing conditions and the inherent variations in the base material.
The second method also requires destructive sampling of the base material.
The object of the present invention is to overcome the problems encountered using present measuring techniques by providing a relatively simple, accurate method of determining the quantity of chemical being added to a fabric on a continuous basis.
Accordingly, the present invention relates to a method of monitoring the production of protective clothing fabric of the type including a chemical incorporated therein by impregnation comprising the step of:
(a) monitoring the magnetic susceptibility of the impregnated fabric to determine the quantity of chemical added to the fabric.
In a specific application of the method of the present invention, commercially available magnetic susceptibility measuring instruments are used to monitor the quantity of charcoal being added to protective fabric. The use of a sensor head proximate the path of travel of the material enables continuous, non-destructive monitoring of the ~g~2~3 material. One suitable instrument for this purpose is susceptibility meter available from Sapphire Instruments of Windsor, Ontario. Another, slightly more sensitive instrument used experimentally, but no longer commercially available is the VGF KL-l magnetic susceptibility bridge.
In order to test the method, a magnetic tracer, which in this case was magnetite (Fe304) was uniformly mixed with a regular charcoal slurry in a variety of quantities based on the quantities of charcoal in the slurry. This experiment was intended to determine an acceptable tracer level. Loadings ranged from 0.04 to 20 g/m2 of magnetite on the base fabric. An extremely linear relationship exists between the loading of magnetite and the magnetic susceptibility through in excess of three orders of magnitude.
In addition to the above mentioned experiment, values for three different magnetic susceptibility instruments were obtained to determine the range of tracer loading required to effect reasonable monitoring of charcoal addition.
For a JH-8 susceptibility meter, approximately 3 - 20%, preferably 6% magnetite on a solids basis (1.8 - 11.8, preferably 3.5 parts magnetite per 100 parts by weight charcoal) were required. The Sapphire Instruments device requires cut samples. However, if a sensor head is used, continuous monitoring can be effected. The quantity of tracer required for the Sapphire Instruments equipment was 0.5 to 10%, preferably 1~ magnetite on a solids basis (0.3 - 5.9, preferably 0.6 parts per 100 parts by weight charcoal). The VGF KL-l magnetic susceptibillty bridge also requires cut samples in the absence of a sensor head, and a magnetic tracer in the amount of 0.5 to 10%, preferably 1.7% on a solids basis (0.3 - 5.9, preferably 1 part per 100 parts by weight charcoal).
It will be appreciated that a determination of the correlation between the magnetic susceptibility and the quantity of charcoal or other material being added should be easy to establish. Thus, a direct reading of the quantity of solids being added to the base fabric can be obtained from the magnetic susceptibility instrument. With the continuous monitoring of the quantity of charcoal (or other chemical) being added to the base fabric, the squeeze roll pressure and other parameters can be varied to ensure that the charcoal concentration in the finished product is more or less constant over the entire length thereof.
Due care must be taken during mixing and impregnation of material that no metals capable of attracting the magnetite are used. It is also worth noting that the particle size of the magnetite may have an effect on the magnetic susceptibility of the material.
Another experiment performed using magnetic susceptibility instruments is the measurement of the magnetic susceptibility of a plurality of charcoal impregnated foam samples over a wide range of charcoal concentrations in the ~Z~9;243 absence of magnetic tracer. The tests showed a correlation between the quantity of added charcoal and magnetic susceptibility. However, the magnetic response was weaker than for samples containing magnetite tracer. Unimpregnated material had no measurable magnetic susceptibility. It appears that the charcoal used has an inherent magnetic susceptibility which raises the question of whether the tracer is absolutely necessary. Of course, in the absence of a magnetic tracer, the chemical being added to the base fabric must have an inherent magnetic susceptibility.
While magnetite is the specific magnetic tracer used in the above examples, it will be appreciated that other minerals such as titanomagnetite, ilmenite and pyrrhotite can be used as the magnetic tracer. A tracer such as HgCo(NCS)4, which is a highly paramagnetic complex, could also be used, permitting the use of lower quantities of tracer in the impregnating slurries or solutions.
Thus, there has been described a relatively simple method of monitoring and assisting in the control of the finishing of a fabric, i.e. the addition of a chemical to the fabric to alter the properties thereof.
Claims (7)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:
1. A method of monitoring the production of protective clothing fabric of the type including a chemical incorporated therein by impregnation comprising the step of:
(a) when the chemical has an inherent magnetic susceptibility, monitoring the magnetic susceptibility of the fabric during impregnation to determine the quantity of chemical added to the fabric.
(a) when the chemical has an inherent magnetic susceptibility, monitoring the magnetic susceptibility of the fabric during impregnation to determine the quantity of chemical added to the fabric.
2. A method according to claim 1, including the step of:
(b) uniformly mixing a magnetic tracer with an impregnation liquid containing said chemical, whereby monitoring of the magnetic susceptibility of the impregnated fabric determines the quantity of magnetic tracer and consequently the quantity of chemical added to the fabric even when the magnetic susceptibility of the chemical is low or nonexistent.
(b) uniformly mixing a magnetic tracer with an impregnation liquid containing said chemical, whereby monitoring of the magnetic susceptibility of the impregnated fabric determines the quantity of magnetic tracer and consequently the quantity of chemical added to the fabric even when the magnetic susceptibility of the chemical is low or nonexistent.
3. A method according to claim 1 or 2, wherein said chemical is charcoal to be added to the fabric as a barrier material.
4. A method according to claim 2, wherein said magnetic tracer is selected from the group consisting of magnetite, titanomagnetite, ilmenite and pyrrhotite.
5. A method of controlling the production of a clothing fabric of the type including charcoal as a barrier material comprising the step of:
(a) when the charcoal has an inherent magnetic susceptibility, monitoring the magnetic susceptibility of the fabric during impregnation with a charcoal slurry to determine the quantity of charcoal added to the fabric.
(a) when the charcoal has an inherent magnetic susceptibility, monitoring the magnetic susceptibility of the fabric during impregnation with a charcoal slurry to determine the quantity of charcoal added to the fabric.
6. A method according to claim 5, including the step of:
(b) uniformly mixing a magnetic tracer with the charcoal slurry, whereby monitoring of the magnetic susceptibility of the impregnated fabric determines the quantity of magnetic tracer and consequently the quantity of charcoal added to the fabric even when the magnetic susceptibility of the charcoal is low or nonexistent.
(b) uniformly mixing a magnetic tracer with the charcoal slurry, whereby monitoring of the magnetic susceptibility of the impregnated fabric determines the quantity of magnetic tracer and consequently the quantity of charcoal added to the fabric even when the magnetic susceptibility of the charcoal is low or nonexistent.
7. A method according to claim 6, wherein said magnetic tracer is magnetite.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000578477A CA1299243C (en) | 1988-09-26 | 1988-09-26 | Method of monitoring production of protective fabric |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000578477A CA1299243C (en) | 1988-09-26 | 1988-09-26 | Method of monitoring production of protective fabric |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1299243C true CA1299243C (en) | 1992-04-21 |
Family
ID=4138789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000578477A Expired - Lifetime CA1299243C (en) | 1988-09-26 | 1988-09-26 | Method of monitoring production of protective fabric |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1299243C (en) |
-
1988
- 1988-09-26 CA CA000578477A patent/CA1299243C/en not_active Expired - Lifetime
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |