DD202320A5 - NUTRIOT FABRICS AND METHOD OF MANUFACTURE - Google Patents

Abstract

Stitch bonded fabrics were found to be suitable substrates for coated abrasives when the fabric has a strength in the warp direction of at least 30 dekanewtons (daN) per centimeter (cm) of width, a fill yarn cover factor of at least 40%, and stitch yarns with a tensile strength of at least 0.5 daN. For substitution of the established commercial classes of abrasives known as X and Y weights, the fabrics are preferably made on a Malimo machine, with 14-22 warp yarns of 840-1300 denier high tenacity multifilament polyester or glass per 25 cm of fabric width, at least 64 fill yarns of staple or texturized multifilament polyester per 25 cm of fabric length, and stitch yarns of 70-140 denier high tenacity multifilament polyester.

Description

The present invention relates to stitchbonded fabrics which are particularly suitable for "reinforcing the backing of abrasive fabrics.

Characteristic of the known technical solutions:

Sewing knits in general have been known for at least twenty years. However, it has not been recognized that these fabrics can provide particular advantages when used as a reinforcing substrate for abrasive cloth underlays. Thus, the applicant is not aware of any tissues that are expressly suitable for this purpose.

In order to be able to produce sewing fabrics on a large scale at low cost, one must use one of the special machines designed for this purpose. It stands one

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large "variety of these machines available, commercially, including those traded under the name Malimo (short for MALIMO type Malimo), by the Unitechna foreign trade mbH Karl-Marx-Stadt, GDR, which is called Weft / Loc of the Liba Maschinenfabrik GmbH , D 8674 Haila, FRG, and Raschel knitting machines. (A list of suppliers of Raschel machines is given on pages 31 to 38 of Volume 43, "Ur. 35, Knitting Times, the official publication of the National Knitted Outerwear Assoc., 51 Madison Avenue, Hew York, Hew York, 10010. )

These commercially available machines are generally limited to a maximum of about one warp yarn per millimeter (mm) fabric width. It is believed that this limitation is necessary in order to be able to place a sufficient number of piercing or forming elements in the machine in order to be able to make bonds across the entire width of the fabric substantially simultaneously. Since conventionally woven sole fabrics usually have at least twice the warp yarns, it has not been possible to easily transfer the design of conventional fabrics to the requirements of stitchbonding machines.

It should be noted that in many of these machines more than one warp yarn may be passed through each of the openings provided for these yarns in the machines. But any variety of yarns fed through an opening is bound by the machine like a single yarn or thread. Thus, the practical effect achieved by such a plurality of yarns inserted through an opening is substantially the same as when using a twisted yarn in which the number of twists is equal to the plurality of individual, untwisted yarns is. Both woven and stitched fabrics are

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the results achieved by using such twisted yarns are generally not as satisfactory as regards the use as a fabric backing layer and the desirable combination of strength and flexibility that can be achieved with equally spaced finer yarns having the same warp overall tensile strength.

As will be explained below, the preferred machines for the fabrics of the present invention are those of the Malimo type, a publication of the manufacturer of Malimo machines, the VEB Mhwirkmaschinenbau Malimo, Karl-Marx-Stadt, DDR, Hr. 24-2 / 3, "MALIMO Sewing Machines, Technical Possibilities and Technology", Part 2 (marked at the end as Ag 07/010 / 77.-Ill 3 1 74/8900/77 1,0), describes the general scope of the for machines of this special type possible operating conditions. The following description of the mechanical properties of Malimo machines takes from the cited publication the characteristics which Applicant considers particularly relevant to the construction of fabrics suitable for use in abrasive fabrics. In this summary, the term "shot" has been changed to "fill" in accordance with US practice, and the term "hook needle" has been shortened to "hook", all other terms describing the mechanical parts of the machines have been used directly Reference publication taken. ~

Malimo machines have three basic mechanical properties that limit the variety of tissue structure that can be achieved. The first of these constraints is related to a set of different coordinated mechanical structures that define a maximum "gauge" or maximum number of 25mm width yarns for warp and j-thread combinations that are possible with the machine. The manufacturer can deliver between 3 and 22 in twelve different gauges.

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The second major mechanical limitation of Malimo machines is stitch length. It can be regulated in 20 steps within the range of 0.7 to 5 mm. It should be noted that this nominal "stitch length" is in fact the length benefited in the direction of the warp yarns. When working with a stitch in a chain style, as is the case with the fabrics of the pail described herein, the actual spatial orientation of the stitch is at a considerable angle to the warp threads, and the actual length is therefore greater than the hominelength. In addition, since the stitch threads form loops, the length of the yarn consumed for each stitch is generally significantly greater than the nominal length as well as the actual length. In the fabrics described below, the consumption of stitch yarn was about four times the consumption of warp thread.

The third of the main mechanical limitations of the machine results from the arrangement of the hooks which hold the wefts in tension until they can be sewn to the chain. There are hook units with a linear density, from 8 to 48 hooks each 25 mm. Under normal working conditions, as stated in the instructions given by the manufacturer, no more than one sheet of weft should be placed around each hook when making fabrics.

It should be noted that it is a characteristic feature of • Malimo machines; is that · the weft threads ^; in two distinct groups with small, symmetrical angles' on the opposite sides of an imaginary line that is perpendicular to the warp yarn arrangement. It should be noted that all weft yarn information in this specification includes these two weft yarn groups in the count.

The Malimo publication cited above and accompanying hereby gives some peculiarities of the construction of various fabrics suitable for applications other than abrasive fabrics. This is the largest such description of specific sewing fabrics known to the Applicant.

Explanation of the essence of the invention:

Subject of the present invention, it has been found possible by the careful selection and combination of certain types and sizes of yarns and by operating the commercially available machinery outside the scope of the manufacturer's instruction manual to produce economically effective fabrics for a wide variety of abrasive fabrics. In general, a satisfactory fabric is obtained when the warp yarn assembly has a tensile strength of at least 30 dall per centimeter fabric width, the weft assembly has a density factor as defined below of at least 40 % , and the stitch yarns have a tensile strength of at least 0.5 daN each. In most cases, this result is preferably achieved by using warp yarn assemblies with higher denier yarns, high strength synthetic filament yarn of indefinite length or glass in a number of at least 12 yarns per 25 mm fabric width, textured filament weft yarn yarn assemblies of indefinite length lower filaments Denier or manmade fiber yarn in a number of at least 64 threads per 25 mm of fabric length and by stitch yarns of a finer denier with a tensile strength of at least 0.007 daH per denier achieved.

For the production of fabrics according to the present invention, preference has been given to Malimo machines, model Hr. 14010 or 14011. Liba machines and Raschel knitting machines can be used to produce equally satisfactory

However, their working speed is limited so that they are not so economical.

It has been found desirable to provide reinforcing fabrics of the new type having tensile strengths at least equal to those of conventional abrasive fabrics having conventional fabric support layers. Two of the most important classes of these abrasive fabrics, which are normally called "weight X" and "weight Y" in trade, have tensile strengths of about 30 and 38 daU / cm width, respectively. It has been found that this value of the tensile strength in stitchbonded fabrics by the use of Kettgauges 12-22 in synthetic yarn be achieved from monofilaments of indefinite length or glass fiber yarns with a breaking strength of at least 0,007 deca Newtons per denier can be delayed. When using a coarser gauge, adequate tensile strength can be achieved even with higher denier yarns.

Although high tenacity yarns are very effective in achieving warp tensile strength, they offer relatively little coverage or opportunities for easy, mechanically assisted adhesion of the finish adhesives needed to complete the entire backing layer on which the abrasive fabric is to be made become. It has been found that these deficiencies can be counterbalanced by the use of a high linear density of relatively narrow spun staple or textured weft yarns of yarn of 'monofilaments of indefinite length'. The greater effective surface area, per unit of mass of these yarns compared to the wedge yarns, provides better opportunities for the mechanical adhesion of the finish adhesives and the achievement of adequate coverage when combined with suitable finishing processing techniques.

241982 2

An important feature of the invention, particularly useful in facilitating adequate coverage in tissue, is the plague of making it possible to make tissue with two or more wefts on each hook when working outside of the operating instructions associated with malaria. Machine to be delivered. If the machine drive is adjusted so that the weft carriers, that is a mechanical part other than and distinct from the hook carriers, will move forward at half the minimum speed recommended by the manufacturer for the particular combination of hook spacing and number is recommended to the supplied wefts, an average of two threads per hook can be maintained. Alternatively, the speed may remain unchanged while the width of the weft carrier is doubled. Similarly, a work of the wearer at a quarter of the recommended speed or a tuber increase in width would result in an average of four threads held by each hook. 5 mm high hooks were used for all designs, except for fabrics with 500 denier wefts, better results were achieved with 7 mm hooks on these thicker yarns. Medium-sized sliding and closing wires, guide holes for the 1.8 mm diameter stitching thread and Round, instead of oval holding pins offered by the manufacturer were chosen for the fabrics shown. Weft carrier and hook carriers having 32 apertures of 25 mm each were used for fabrics with 64 or 128 wefts each 25 mm and carrier reeds and hook holders with 24 apertures each 25 mm for 96 wefts each 25 mm.

Additional possibilities for adhesion and coverage are provided by the stitch yarns. It has been found that synthetic filaments of monofilaments of unlimited length in denier between 70 and 220 are very well suited as stitch yarns for these fabrics. In addition to the elasticity and flexibility of the stitch yarn for effective work of a Uähwirkma-

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are the main requirement that is placed on the stitch yarn in abrasives., a sufficient strength to withstand the crack of weft and Kettfadenanordnungen under conditions of use can. It has been found by experiments that a polyester yarn of 70 denier having a tenacity of at least 0.008 daH / den is adequate for most purposes. For abrasive fabrics, however, which are to be used under extremely severe conditions, it is advantageous to work with stitch yarns of 110, 140 or even 220 denier.

In general, shorter stitch lengths result in fabrics having a more uniform appearance, while larger stitch lengths are more economical in the result of higher production speeds. For backing fabric for. Abrasive fabrics proved to be advisable not to work with a stitch length of more than 1.8 mm. For most fabrics, the preferred range is 1.2 to 1.8 mm.

Each stitch typically forms a loop around only one warp thread (if not more than one thread is passed through a single opening, as stated above), but the number of wefts within a stitch loop may be between and less than one and several depending on how many wefts happen to occupy the space within the fixed stitch length. For long stitches and average weft density, an arbitrary pattern of short, relatively open spaces can often be found in the fabric being made, as a result of the fact that the average number of filler threads taken within the loop of the particular stitch is is exceeded or fallen below. This pattern has not proved to be detrimental to the abrasive fabrics made with such fabrics as backing sheets within the limits described herein.

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Table 1 shows some non-limiting examples of particular fabric constructions sufficient for abrasive fabrics. All of these fabrics were made with hook carriers with no more than 32 hooks each 25 mm.

- Characteristics of the warp arrangement Thread size Fa- The festgk. ^ 3 e daN / cm 25 mm width 44 5, which as Carrier layer for Thread size Fa the je 25mm Condi- daN / cm width Dirt Shabu Thread size sting Yarn fiber type 1000/192 14 57 Characteristics of the weft arrangement 170/33 64 15 40.7 % Characteristics of the 70 Stitch length mm Poly-3 ester 1300/192 14 48 Yarn fiber type 170/33 128 30 81.4 % Yarn f _a ser type 140 1.2 Poly-3 ester 840/140 18 57 Poly ₄ esters 170/33 96 22 61.0 % Polyesters, esters 70 1.2 Poly-3 ester 1300/192 14 57 Poly ₄ esters 443 96 48 98.0% Poly- ₅ ester 150 1.2 Table 1 Poly-3 ester 1300/192 14 44 Poly ₄ esters 3 300 96 53 81.0% Poly-c ester 220 1.2 Some specific examples of stitchbonded fabrics are suitable Poly-3 ester 1000/200 14 62 Poly ₆ wster 150/34 128 26 77.0 % Poly ester ₇ 110 1.2 Gewe- Polyvinylalcohol ^x 1200/200 14 mixed 443 96 48 98.0 % Poly ₅ eater 140 1.2 at the same time. No. Polyvinyl _T0 kohol ' ^u Poly ester ₇ Poly- ₅ ester 1.4 1 Poly- ester ₆ Poly- ₅ ester 2 3 4 5 6 7

Table 1 (Port setting)

Some specific examples of stitchbonded fabrics suitable as backing for abrasive fabrics '''

Gewebei-

Characteristics of the warp arrangement Characteristics of the weft arrangement

Characteristics of the engraving

Yarn- Paden- Pa- Draws- Yarn- Paden- Pa- Draw- Yarn- Yarn- Paden- Stitch- Fiber size the festgk. fiber size the stigk. te- fiber size length

each daN / cm type per daN / cm fakn type mm

mm width 25mm width gate

8 glass - 1207 14 EGG-37

9 glass EGG-1207

10 glass ECH-1786 25? T

14

14

11 poly-3 1300/192 14 esters

170/33

Poly ₄ esters

Poly - 2 500 amido

₈ 300 mixes

Poly-.2 500 amido

128 64 96

64

30 53 53 53

81.4 70.0 81.0 70.0

Poly- ₅ 70 esters

Poly ₅ 220 ester

Poly ₅ 220

ester

Poly ₅ 220

ester

1.2

1.2 1.8 1.2

1. The first number in this column indicates the yarn size in denier, that is the mass in grams of 9OOO m of the yarn. The number after the slash indicates, as far as available, the number of individual filaments of unlimited length in each yarn according to the manufacturer's instructions.

2. See the specification of the calculation method for the density factor.

3 · The model 68 Dacron from duPont was used.

4. It was textured with! Pertrel yarn type 731 from Celanese worked.

5. Ss were working with high-tenacity 68 Dacron yarn from duPont.

6. Work was done with spun staple polyester fibers, either duPont 54W or Celanese type 310.

7. It was textured with! Yarn, type 56T Dacron, made by duPont.

8. It was a special yarn with a core of Dacron

Type 68 L and an outer surface made of spun cotton. About 30 % of the total weight of the yarn was cotton.

9 ^:. It was worked with / Kurälon type 1225-7 of the Kuraray Co., Ltd., (Japan).

10. Kurolon Type 1239 was used by Kuraray Co., Ltd., (Japan).

11. The yarn used was purchased from PPG Industries, Inc.

4 I 9 fl?

12. Cordura-Uylon, type 439, was used by duPont.

The density factor for the weft assembly in Table 1 is the same as the value often referred to as the "relative coverage" of others, that is, the portion of the total area enclosed by the boundaries of a tissue sample covered by the weft assembly therein. In principle, this value could easily be calculated from the knowledge of the linear density and the diameter of the wefts: If η is the number of wefts per unit length of fabric and d is the diameter of each thread in the same units, then the density factor is equal to 100 nd %, In In practice, the accurate measurement of the yarn diameter is very difficult, and in accordance with the usual precision in the textile industry, the density factor used here was determined by indirect calculation, taking advantage of the density and denier size of the yarn. From the definition of denier (see footnote 1 in Table 1) it can be seen that the mass divided by grams of a centimeter of length of yarn equal to the denier value (D)

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by 9x10 '. The volume ν in cm of the same yarn length is approximated by that of a cylinder of the same diameter, so that ν = (T * d) / 4. According to the definition, density ρ = m / v. The combination and conversion of these expressions gives the percentage density factor = n (4D / 90 ρΤΊ ^1/2 .

The density of a yarn, in turn, depends on the bulk density of the composites of which it is composed and on the density of the packing. The latter property of the yarn is quantified as a packing relation and, when multiplied by the fiber density, gives the yarn density. The following values were determined for the pore density of the weft threads listed in Table 1.

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fibers, in g / cm, assumed: polyester 1,3; Cotton 1.56; Polyamide 1.14 · The assumed packing ratios were: textured polyamide 0.80, textured polyester 0.70, staple polyester 0.59, and blended yarn 1.0.

It should be carefully noted that in the above density factor calculations it is assumed that the wefts have the position in which they were placed prior to sewing. Small deviations from this value are assumed after sewing the fabric together. It was not attempted to calculate these latter deviations, as they obviously did not affect the behavior of the abrasive fabrics made with the fabrics described herein as backing. However, fabrics having a density factor of the weft of less than 40 %, according to the above calculations, could hardly be prepared to be suitable for receiving the adhesives and the layers in the production process of abrasive fabrics having a conventional continuous support layer.

The fabrics listed in Table 1 and other fabrics constructed according to the same principles may be finished in a variety of ways to make suitable abrasive cloth backing sheets. These backing layers, in turn, may be coated with a variety of adhesives, abrasives, and sizing class adhesives well known in the art. Some specific examples of these ways of applying the present invention will be given below, and others will be readily apparent to those skilled in the abrasive product art after considering the above description in connection with the above-mentioned application.

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Exemplary embodiments: Example 1

It became tissue with structure after, the Identifikationsirr. 1 of Table 1 used. This fabric was then soaked with a resin and an acrylic latex composition to prepare it for the front finish, the back finish, and the coating with the grain material and size coat. The heat-setting step is combined with the drying of the impregnating agent. The steps for completing the fabric will be described in detail below.

Saturation and heat fixation

With standard size rollers, the following composition is applied in an amount of 40 to 60 g / m. The weft side of the fabric pointed upwards.

saturation composition

Cymel "482, available from America Cynamid, a melamine-formaldehyde resin syrup, 80 % solids, pH 8-9,160 parts

Beetle 7238, available from American Cynamid, a urea-formaldehyde resin syrup, 65% solids .124 parts water 120 parts Aqueous solution containing 15% 1H.C1 and 24 % 2-amino-2-methylpropanol 13 parts 5 to 7 parts of pigment dispersions can be added to the color supplement.

After application of the saturant or impregnant, the fabric is dried on a tenter for at least 3 minutes in a hot air oven, in which

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the temperature in the inlet zone 96 C and in the exit zone 177 ⁰ C. During this movement through the oven, a tension of at least 3.5 Newtons per centimeter (ϊΓ / cm) of width is maintained on the fabric. This method not only dries the impregnating agent but also heat-fixes the fabric.

Prede re A ppreturschicht

The composition of the front finish layer applied to the weft side in this example but which, if desired, is also applied to the warp side, is as follows:

(1) Phenol-formaldehyde resole resin in the Α-state with a ratio of formaldehyde to phenol of 1.5 and a pesticide content of 78% 199 parts

(2) CaCO ₃ 160 parts

(3) Hatrium lauryl sulfate 2 parts

(4) Hycar 2600 χ 138, a latex of a Akrylsäureesterpolymer with a Glasumwandlungstemperatur'von 25 ⁰ C, available from

B. Goodrich Chemical Company 54 parts

The front finish layer composition is measured with a knife in an amount of 150 to 165 dry grams per each

P '"' ...

Square meter (g / m) and water may be added as necessary to obtain the required viscosity for proper coating. The coated fabric is in turn dried on a tenter with a tension of at least 3, 5 IT / cm width, for which it is passed through a hot air oven whose inlet temperatures 96 ⁰ C and whose temperature in the exit zone 150 ⁰ C.

- 17 Rear finishing layer

On the side which is not coated with the front finish, a rear coating finish layer having the following composition is applied:

(1) Beetle 7238, a urea-formaldehyde resin syrup available from American Cynamid 133 parts

(2) Uopco®, Foaming Inhibiting Agent, available from Hopco Chemical Co.,

Newark, Hew Jersey 5.3 parts

(3) adhesive UCAR 131, a follow-60 Polyethylenpolyvinylazetatdispersion aqueous, available from Union Carbide Corporation,

with a pH of 4 to 6 133 parts

(4) Air-washed clay 176 parts

(5) Aqueous solution containing 15 % ΈΕ

- 24 % 2-amino-2-methylpropanol contains 5.3 parts

(6) water - to bring the viscosity to 11,000 cps at room temperature, as far as that is required (if desired, pigment can be added to the color supplement)

The composition is applied by a knife at a rate of 140 to 165 g / m and dried in an oven having an inlet emper temperature of 66 ° C and an outlet zone temperature of 93 ° C.

The thus-coated fabric can now receive a layer of phenolic resin, the abrasive, and the abrasive sizing layer, as is common practice. A suitable composition that can be applied to the front sizing side of the carrier layer is the following:

(1) Alkali catalyzed phenol-formaldehyde resole resin, F / P factor 2.08, pH 8.7, 78 % pesticides in water 7 parts

(2) Alkali catalyzed phenol-formaldehyde resole resin,

F / P 0.94, pH 8.1, 78 % solids in H _P O

3 parts

(3) CaCO ₃ 'x 1.54

solid

gesamtge-

stop

On the adhesive-coated fabric is then applied by conventional electrostatic means an amount of 520 to 550 g / m of abrasive grain Grit 60 made of high-purity alumina. The adhesive-coated abrasive backing member is then heated for 25 minutes at 77 C, 25 min at 88 ⁰ C and 47 min at 107 ⁰ C to give a dry

Bonding layer (about 260 g / m) to form and anchor the abrasive grains in the desired orientation.

Then a sizing layer (about 16O g / m dry) with. the same composition as the previous layer, but with lower viscosity, applied by the usual methods. The wet adhesive layer is then dried: 25 min at 52 ⁰ C, 25 min at 57 ⁰ C, 18 min at 82 ⁰ C, 25 min at 88 ⁰ C and 15 min at 107 ⁰ C, whereupon the final drying at 110 ⁰ C. for 8 hours. The abrasive cloth can then be converted into belts, wafers and other desired abrasive products by the usual methods.

While in the above example the finish of the backing layer was done with the abrasive layer on the weft side of the fabric, in other cases it may be more convenient to coat the warp side of the fabric.

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2/1 O O O O '' W W ^ "<& D

Example 2:

Fabric with the design according to the identification Hr. 3 in Table 1 was coated by the dip-squeeze method with a two-roll padding machine using the following impregnant.

Imprägniermittelformel;

1. Water (tap water) 183.3 parts

2. Hatriumhydroside (HaOH - solid flakes) 2.2 parts

3. Beserzin 13.5 parts

4. Formaldehyde, 37 % ± aqueous solution 14.2 parts

5. Hycar 2600 χ 138 81.3 parts -6. 2% by weight of HAOH in water (foam bil.

suppressors, if necessary)

mixing instructions

Dissolve position 2 in position 1 with stirring, then add position 3 and stir until dissolved. Add position 4 and stir for 5 minutes; Weigh out position 5 in a separate container and add position 6 with stirring to bring the pH close to that of the RF premix (about 9), then place the premix in position 5 with gentle stirring. If foam develops during the addition, add small amounts of suds suppressor (Faleoban S, manufactured by Fallk Chemical Corp., 46Ο Park Avenue, Hew York, HY 10022) was suitable, but many other agents are equally suitable Foam coating developed, additional suds suppressor may be added.) This mixture should be stirred for at least 15 minutes after the last addition and left to stand for 24 hours before use.

After coating, the fabric was held in a tenter frame to prevent shrinkage in width, and for drying by an oven with an inlet Sonen temperature of 135 ⁰ C and out an exit zone temperature of 240 ⁰ C, duration of the drying treatment 3.75 min. Ss enough impregnant was used,

+ 2 to achieve a dry addition of 52-7 g / m.

After impregnation and drying in the manner described above, the fabric on the side on which the warp threads are most pronounced was coated with the adhesive mixture shown below on the back:

Resole phenol-formaldehyde resin having a molar ratio of formaldehyde to phenol of about 2.1 to 394 parts; Resole phenolic resin having a F / P molar ratio of about 0.95 parts; Calcium carbonate (classified as described in US Pat. No. 2,322,156) - 850 parts; Hycar'2600 χ 138, Akryllatex (previously adjusted to a pH of 8 to 9 with 10% aqueous sodium hydroxide solution) - 102 parts.

In the preparation of this solution, the ingredients are added in the order listed with constant stirring. The adhesive is applied to the impregnated fabric by a knife rollover method in an amount sufficient to give, after drying, an amount of adhesive of 175 to 225 g / m 2. For drying, the coated fabric is placed back on a tenter to avoid possible loss in width, and for the. Duration of 3 "75" passed through an oven with an inlet zone temperature of 65 ⁰ C and an outlet zone temperature of 107 ° C.

The backed fabric was then used on the opposite side with a face finish of the same composition as used for

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the backslide finish was used, in sufficient quantity by a Torder side finish of dry 120 to

2 180 g / m to give. The coating of the front could be done with the knife or with the roll method, the effectiveness is approximately the same in both cases. The oven conditions for drying the front finish were the same as for the backside finish, but in this case, satisfactory results can be obtained without the use of a tenter, if desired.

If after completion of the above steps is undesirable roughness on the surface of the finished fabric, a calendering treatment at a Durck of about 350 Dau / cm width was performed by conventional calender rolls which were heated to a temperature of 63 ⁰ C.

The finished carrier layer could then be subjected to the remaining treatment steps to produce an abrasive fabric by conventional methods, as briefly described in Example 1.

Example 3:

Tissue # 8 from Table 1 was used for this example. All other steps were the same as in Example 2.

Table 2 shows the physical properties of the abrasive fabrics prepared in Examples 1 to 3 and compares them with similar measurements on commercially available abrasive cloth products with a woven backing. The tensile strength of the products described here is comparable to that of the commercial products in Example 1 and is superior to Examples 2 and 3.

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lay. The tear limit, which is generally related to the resistance to environmental hazards during the use of abrasive cloths, is remarkably better in Example 2 and approximately comparable in the other cases. Elongation is lower in Examples 1 and greater, and lower in Fabric 3.

Table 2

Comparison of physical properties of abrasive fabrics .

Identical-% expansion at break

fiction stig. shown tensile force (in dal ·! / cm) limit

of the (dal / cm) in Rieht. of Pr o -

Schieif- in Rieht. l

Chain shot

18 26 35 breakage breakage

R 267, ο 49 15 1,2 2,5 4,3 7,5 15,0 116 Grit 60 ^J

Example 1 47 H 3,3 6,6 9,2 13,5 17,6 120

Example 2 57 31 2.0 5.0 7.4 14.0 15.1 288

Example 3-59 16 0.8 1.2 1.7 3.3 6.5 113

R 811, ·

Grit 6O- ³ 44 13 0.9 1.7 3.0 5.0 18.8 116

1) ^J This measurement was performed according to ASTM D 1682-64, but the sample length was 25.4 cm instead of 7.6 cm; regardless of the time to break, a fixed strain rate of 12.7 cm / min was used.

This value was measured with a Mullen Burst Tester, an instrument available from Roehlen Industries, Chicopee, Massachuetts, USA.

Commercially available Y-weight abrasive fabrics available from Norton Company, Worcester, Massachusetts.

_23- '· "". W <fc & m

Excessive elongation, especially when it exceeds the setting capacity of the particular machine to which a sanding belt is used, is undesirable, but otherwise stretching is not known to have a significant effect on shooting performance. Thus, if required, very stretch resistant warp yarns such as the Example 3 glass fiber can be used, and the greater general toughness of a more easily warpable warp type such as polyester can be used to advantage unless maximum resistance to stretch is required.

The adequate performance of the abrasive fabrics made in Examples 1 to 3 is confirmed by actual laboratory and practical sanding trials.

It should be noted that the term "yarn" as used in the present specification and claim makes any continuous linear structures of any fiber type, twisted or laid together, of natural or man-made fibers, including the monofilament, more indefinitely For the purposes of the present invention, however, uncashed short fibers are not referred to as yarns Thus, the fibers in mats or nonwovens are not yarns as defined above, in particular the so-called "weft" or "weft" yarns. Both weft and warp yarns, although possibly composed of twisted (and thus consolidated) short fibers, are usually continuous over dimensions several times longer than the width of a fabric, often hundreds of meters or more Such continuity can, of course, be achieved by knotting or otherwise joining previously separate structures during the manufacture of a fabric.

Claims (9)

Invention claim: 1. üähwirkgewebe, characterized in that: (a) a warp thread assembly having a tensile strength of at least 30 decanewtons per centimeter of fabric width , (b) a weft assembly disposed on one side of the warp yarn assembly and having a density factor of at least 40%; and (c) a plurality of stitching yarns, each of said yarns having a tensile breaking strength of at least 0.5 decanewtons formed in stitching or knitting loops around groups of individual yarn elements of the warp and weft yarn assemblies, whereby the two yarn assemblies are joined together to form a coherent fabric connected. 2. fabric according to item 1, characterized in that the number of stitch threads is at least as large as the number of warp threads. 3. fabric according to item 1 or 2, characterized in that the warp thread assembly consists of threads with substantially the same distance and whose number is not greater than one thread per millimeter fabric width. , 4. A fabric according to any one of the preceding claims, characterized in that at least half the volume of the threads of the warp thread assembly consists of fibers of a polyester, polyamide, polyvinyl alcohol or glass. 5. fabric according to any one of the preceding points, characterized in that the weft arrangement has more than 25 threads per centimeter of fabric length. 241982 6. Fabric according to one of the preceding points, characterized in that at least half the volume of the threads of the weft thread assembly of a gesponnnenen staple polyester, textured polyester yarn with Einzelfäden.unlimited length or textured polyamide yarn consists of filaments of unlimited length. , 7. fabric according to one of the above Pankte, characterized in that at least half the volume of the stitch threads made of fibers with a tensile strength of at least 0.007 Dekanewton'je denier. 8. fabric according to any one of the preceding points, characterized in that at least half the volume of the stitch yarn consists of polyester. A method of making a stitchbonded fabric, characterized by the steps of (a) holding a tensioned first thread assembly between rows of hooks disposed along both sides of a second thread assembly, and (b) moving the first thread assembly by moving the rows of hooks in which it is held, in a position in which the first yarn arrangement, substantially simultaneously over the entire fabric width, can be bound to the second yarn assembly by stitching or knitting loops formed by yarns extending from the yarns the first and second thread arrangement, wherein at least two threads of the first arrangement are held on each hook of said hook rows.