GB1575972A - Polyester fabric for use as a backing material in coated abrasive product produced therewith - Google Patents

Abstract

The fabric contains a polyester, it has undergone heat setting and relaxation, and its dimensions are stabilised in the warp direction, for which reason it has an extension less than 6.5 % for a tensile strength of 300 N per linear cm of width. Manufactured by the method, the fabric retains the desired width. It can be used for manufacturing abrasive strips and belts, which have a support fabric (20) made of polyester. A filling layer (22) is formed on its lower face, then a finishing layer (24) is formed on the latter. A filling layer (26) is formed on its upper face, then a prefinishing layer (28) is formed on the latter, which prefinishing layer itself carries a holding layer (30) in which the abrasive grains (32) are embedded, covered with a finishing layer (34). <IMAGE>

Description

(54) POLYESTER FABRIC FOR USE AS A BACKING MATERIAL IN COATED ABRASIVE MANUFACTURE AND COATED ABRASIVE PRODUCT PRODUCED THEREWITH (71) We, THE CARBORUNDUM COMPANY, of 1625 Buffalo Avenue, Niagara Falls, New York, United States of America, a corporation organised and existing under the laws of the State of Delaware, United States of America, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention relates to a polyester-containing fabric for use as a backing material for a coated abrasive product, a method of producing such fabric, a coated abrasive product incorporating such fabric, and to a method of producing such a coated abrasive product.

Heretofore, the accepted way of making a coated abrasive product, and especially an endless belt, involved primarily the use of a woven cotton fabric backing material, and to a lesser degree of woven viscose rayon fabric backing. In either case however, these backing materials inherently are limited in strength, toughness, body retention and base adhesion. Moreover, attempts to incorporate an all thermosetting resin system have resulted in unacceptable embrittlement of the fabric backing, especially cotton.

It is an object of the invention to obviate or mitigate the above disadvantages.

According to a first aspect of the present invention there is provided a woven polyester containing fabric suitable for use as a backing material for a coated abrasive product, which fabric has been heat set under tension, whilst maintaining the desired width thereof, so that the fabric has a dimensional stability warpwise of less than 6.5% elongation at 170 pounds per linear inch of width tensile.

According to a second aspect of the invention there is provided a method of producing a fabric as defined in the preceding paragraph, comprising maintaining a woven polyester containing fabric under both warpwise and weftwise tension whilst maintaining its desired width and whilst heating the fabric to a temperature and for a time sufficient to provide the woven fabric with a dimensional stability warpwise of less than 6.5% elongation at 170 pounds per linear inch of width tensile.

The fabric of the invention possesses high strength, toughness, body retention, pliability and base adhesion properties and can be readily used in combination with thermosetting resins without undesirable embrittlement in the manufacture of a coated abrasive product such as described more fully later.

In the method in accordance with the second aspect of the invention for producing the fabric, of the invention one starts with a woven polyester containing fabric which is subjected to heat and to warpwise and weftwise tension. As a result of this method, the fabric is heat set in a condition from which it will not return to its original condition. Such a condition is herein also referred to as a destretched condition.

In the method of the second aspect of the invention, the fabric is preferably heated at a temperature of 400 to 4600F for a time of 0.75 to 2 minutes, more preferably at a temperature of 440"F for a time of 1 to 1.5 minutes to produce the heat set and destretched fabric.

The most preferred fabric for use as a backing material for a coated abrasive product is one woven from 100% polyester fibres in a sateen weave, with the fabric cover - as determined by the Golec formula (see later) of the heat set and destretched fabric being substantially 99.86%. To produce such a fabric by the method of the second aspect of the invention it is preferred to start with a woven fabric with a cover of substantially 96.63 /n and it is also preferred that the warpwise tension is sufficient to provide an average length increase of more than 4% with the weftwise tension being sufficient to limit the average width decrease to 5%.

A coated abrasive product in accordance with the invention may be produced from a fabric in accordance with the invention which has been provided with a cloth finish including fill and front fill coats each of which contains a thermosetting resin. The cloth finished fabric will preferably have a higher dimensional stability warpwise than the fabric before the cloth finish is applied. The coated abrasive product may be produced from the cloth finished fabric by applying successive maker, abrasive and size coats to the front fill coat with the maker and size coats each containing a thermosetting resin, and curing the composite structure to produce the coated abrasive product.

The fill coat of the cloth finished fabric may be a dip-fill coat, in which case the thermosetting resin contained in the dip-fill coat and that contained in the front-fill coat are each preferably phenol formaldehyde resin. Alternatively the fill coat may be a back fill coat and in this case the cloth finish preferably includes a back size coat containing a thermosetting resin. Preferably the thermosetting resin contained in the back size coat and that contained in the front fill coat are each an acrylic polymer, and preferably also the thermosetting resin of the front fill coat will be a phenol-formaldehyde resin.

The thermosetting resin contained in each of the maker and size coats is preferably a phenol formaldehyde resin. Additionally it is preferred to provide a pre-size coat between the front fill coat and the maker coat for enhanced base adhesion. Such pre-size coat will contain a thermosetting resin, preferably a phenol-formaldehyde resin.

The coated abrasive product is preferably an endless belt.

It is an important feature of the coated abrasive products in accordance with the invention that they may be doubled upon themselves across the warp, abrasive side compressed, without shattering and without being readily manually torn across the warp in the crease produced during such doubling.

Additional objectives and advantages of the invention will become evident upon consideration of the following detailed description and accompanying drawings, in which: Fig. 1 is a perspective view of an endless coated abrasive belt in accordance with the invention; Fig. 2 is an enlarged vertical section taken generally along line 2-2 of Fig. 1, and illustrating the laminated construction thereof, with the various layers being disproportionately enlarged for clarity of illustration; Fig. 3 is a view similar to Fig. 2, but illustrates-the laminated cross-section of an alternative embodiment of endless abrasive belt in accordance with the invention Fig. 4 is a schematic side elevation of a preferred apparatus for use in the manufacture of a fabric for use as a backing material in accordance with the invention;; Fig. 5 is a top plan view of the apparatus of Fig. 3.

Fig. 6 is a schematic side elevational view similar to Fig. 4, but illustrating an alternative apparatus for use in the manufacture of a fabric for use as a backing material in accordance with the invention.

Fig. 7 is a top plan view of the apparatus of Fig. 6.

Referring to the drawings, and particularly Fig. 1, a preferred embodiment of coated abrasive belt is generally indicated at 10, and includes a composite or laminated sheet 12 which has its opposite end portions 14, 16 in edge abutting relationship so as to form the endless belt with abrasive side outermost. As should be evident from Fig. 1, these end portions 14, 16 are slit at an angle to the running direction of the belt, as indicated by the (arrows, and the desired butt joint is provided by a patch splice generally indicated at 18. This splice may be of any suitable construction, such as disclosed in U.S. Patents 3,665,660 and 3,763,604.

Alternatively, the belt could be formed with a lap splice by skiving the end portions, interposing a suitable adhesive and then heat pressing the joint, as is well known in the art.

Turning now to Fig. 2, the cross-sectional, multi-layer or laminated construction of the belt of Fig. 1 is illustrated in exaggerated form for clarity. In other words, the proportion of the thickness of the various layers is not to scale, but rather considerably enlarged in order to indicate the presence and nature of each layer and its relationship with the adjacent layers.

Thus, sheet 12 of belt 10 includes a woven fabric backing material 20, preferably of 100% polyester fabric woven from polyester staple fibers in a sateen weave. On the back or lower side of backing material 20, is a back fill coat 22 and on this coat is a back size coat 24. The manner in which these coats are applied will be described in detail below, but it is to be noted at this point that the back fill coat 22 actually impregnates the backing material 20.

On the top or front side of backing material 20 is a front fill coat 26, which also impregnates the fabric, and on top of this is arranged a pre-size coat 28, on top of which is located the maker coat 30. Embedded in the maker coat is a layer of abrasive grain 32, and this layer is, in turn, covered by a size coat 34.

An alternative preferred embodiment of the belt is illustrated in Fig. 3, which is similar to Fig. 2, and where the layers and coats are the same, the same numerals are employed, followed by the small letter "a". However, in the embodiment of Fig. 3, the back fill coat 22 and the back size coat 24 of Fig. 2 are replaced by dipping the fabric backing material 20a in an appropriate fluid composition to provide a dip fill envelope or coat 23a completely surrounding and impregnating both the back and front sides of backing layer 20a. Of course, as shown in Fig. 3, the backing material 20a has been cut to the desired belt width; hence the envelope is removed from the side edges.

In each embodiment, as illustrated in Figs. 2 and 3, however, a critical feature of the construction is the heat set and destretched condition of the backing material prior to the addition of the other layers, and prior to the cutting to belt width.

Continuing with Figs. 1--3, the manufacturing procedure may be said to include 6 basic steps, as follows. In describing such procedure, it is to be noted that Figs. 1--3 show the finished product cut to width, whereas prior to belt formation, the various layers and/or coats are considerably wider, depending upon the width of the woven fabric material roll provided.

The first step is weaving the wide fabric backing material from which the narrow backing material 20 or 20a is formed. The second step is heat setting and destretching such fabric backing material, as will be described in detail below, and with particular reference to Figs. 4-7. The third step is that of cloth finishing, and this includes the application of the back fill coat 22, back size coat 24 and front fill coat 26 of Fig. 2. The same is true for the embodiment of Fig. 3, except that the back fill coat 22 and the back size coat 24 are replaced by the dip coat or envelope 23a.

As an alternative procedure, and as preferred for heavy duty, non-waterproof type belts, such as those illustrated in Figs. 2 and 3, it is both necessary and desirable to include a pre-size coat 28 (Fig. 2) or 28a (Fig. 3), in order to enhance the base adhesion properties of the finished product.

The fourth basic step in such belt manufacture is generally referred to as coating, and this includes the steps of applying the maker coat, the grain layer and the size coat, as illustrated in Figs. 2 and 3.

The fifth basic step or procedure in such belt manufacture is that of curing, which will be explained in more detail below, and involves the heat treating of the coated roll of backing material from which the belt is made.

The sixth and final procedure involves that which is generally referred to as product finishing, and this includes the flexing, and slitting of the roll cured belt matrix into the various desired belt widths, bias cutting and positioning the abutting end portions 14, 16, such as shown in Fig. 1, and applying the splice, such as 18, to complete each individual belt.

Referring now to Figs. 4 and 5, there is shown in schematic outline form such heat setting apparatus which actually was used in heat setting the backing material referred to in each of Examples 1 and 2.

This apparatus includes a supply or unwind roll 40, on which the roll df fabric 200, for making up the narrower backing material 20 (Fig. 2) or 20a (Fig. 3), is supplied. As the wide backing material 200 is fed from left to right; it proceeds from supply roll 40 over support rolls 41, whereupon it is taken off over guide roll 42, and is then passed through nip rolls 43, 44, which are designated as the "NIP 1" position. From here, the backing 20 is fed between nip rolls 45, 46, which constitute the "NIP 2" position, and then proceeds between nip rolls 47, 48, forming the "NIP 3" position, under guide roll 49, over guide roll 50, down under guide rolls 51, 52 and up over guide roll 53 to nip rolls 54, 55, which constitute the "NIP 4" position.

It is to be noted at this point that these nip rolls 54, 55 are driven at variable peripheral speed which is greater than the speed at "NIP 3" position to apply warp tension, but which was less than the tension speed of the chain and clip assemblies described below, (also known as the tenter frame), in order to put additional warp tension on the fabric while it is being heated.

Next, the material passes through the combined heat treating and destretching apparatus generally indicated at 56. This appratus is known as a clip tenter and includes an oven generally indicated at 57 and provided with a number of stations or controls 58 for adjusting and setting the width of the tenter frame. By means of a support structure which is cantilevered at each end, as shown at 59 and 60, such apparatus includes two (or dual) chain and clip mechanisms or assemblies generally indicated at 61, and having a common drive (not shown), for feeding material 200 through oven 57 while maintaining the desired width thereof. To this end, each such assembly or mechanism 61 includes, at the entrance end of the oven a sprocket 62 and at the exit end of the oven another sprocket 63, with the two being connected by a link type chain 64 on which are mounted a series of clip mechanisms 65.The detailed structure of this assembly is disclosed in U.S. Patents 3,180,001 and 3,234,622.

Generally speaking, the clip mechanisms 65 are disengaged on the outer reach of chain 64 and become engaged with the fabric 200 on the inner reaches of the chain in order to maintain the desired width of the material during heat setting and destretching thereof. To facilitate disengagement of the clips with the fabric, the dual assemblies are provided with guides 66 at the exit end of the oven, and which guides are designed to actuate the clips so as to disengage the same from the fabric, in order to facilitate even and uniform passage of the fabric between nip rolls 67, 68 as the fabric leaves oven 57.These nip rolls constitute "NIP 5" position and are driven at variable speed (set at about the same as assemblies 61) to insure proper declipping of the fabric in its running or warp direction as it passes through the heat setting and destretching apparatus, because the wind up roll drive is not adequate for this purpose. Finally, the heat set and destretched fabric is wound on wind up roll 69 for further processing.

In addition to the heat setting apparatus employed in Figs. 4 and 5, that illustrated schematically in Figs. 6 and 7 also has been used to successfully heat set the fabric in practising the inventive method, particularly as set forth in Examples 3-5 below.

Thus, only the differences in the two types of apparatus will be described, with the same numerals being used in Figs. 6 and 7 as for Figs. 4 and 5 to designate like parts, with the addition of the small letter "a".

Referring to Figs. 6 and 7, instead of a supply roll, the fabric 200 may be heat set from a trough 70, whereupon it is passed over a guide roller 71 and under another guide roller 71' prior to passing through the three high vertical stand of squeeze rollers 72, 73 and 74, which replace "NIP 1", "NIP 2" and "NIP 3" positions of Fig. 4. Next, the fabric travels around knurled rollers 75, 76, which have a variable speed drive, prior to entering oven 57a of heat setting apparatus 56a and engagement with the dual chain and clip assemblies 61a. The only differences between these last mentioned parts and those correspondingly numbered parts in Figs. 4 and 5 is the exposure of the support structure at the entrance to the oven 57a, and the elimination of the guides or wings 66a, which have been found not to be necessary with this particular apparatus.Otherwise, the structure and operation of the oven and chain and clip assemblies are just as described above. In operation of the apparatus the knurled rollers 75 and 76 are driven at a peripheral speed greater than that of the squeeze rollers but less than the speed of the chain and clip assemblies 61a.

Following heat setting and destretching, the fabric is passed over the spaced ganged rolls 76', 77, 78 and 79, which replace the nip rolls 67, 68 at "NIP 5" position of Fig. 4. Whereupon, the fabric passes over guide rolls 80 and 81 to the wind up roll 69a.

EXAMPLE 1 A 100% polyester sateen fabric was woven on a standard loom using a high tenacity polyester fiber designated as Eastman-Kodel 421 (Kodel is a Registered Trade Mark). This fiber is believed to be thermoplastic, and has the characteristics of high tenacity, superior strength, high modulus and relatively low elongation.It also has the following properties: Tenacity, 6 g/den; Elongation, 24 /n; Tenacity at 10% Elongation, 4.5 g/den; Initial Modulus, 55 g/den; Average Toughness, 0.90 g/den; Specific Gravity, 1.38; Moisture Regain, 0.40/, at 65 /n RH, 70"F (2l0C); Cross Section, Round; Yarn Shrinkage, in hot water at the boil, 2 minutes, 2%, and in hot oven at 3740F (1900C), 10 minutes, 11%. Tensil properties were measured on single filaments with an Instron Tensil Tester (Instron is a Registered Trade Mark) operated at 700 F, 65% relative humidity.

The above information was obtained from Publication No. TDS K-103a-iII, Fifth Edition 1972 by Eastman Chemical Products, Inc., Kingsport, Tennessee.

The fabric was a 5 harness, 4/1 sateen construction using such 2 denier, industrial grade, high tenacity, polyester staple fiber. The fabric was woven with 96 warp yarns, 13/1, and 42 filling yarns 23/1, at a nominal weight of 1.42 yards per pound and a width of 60 inches. This construction produced a fabric weight of 6.76 ounces per square yard and a woven fabric cover of 96.63%. The calculation for fabric weight is 1 poundxl6 ounces per pound x 36 inches per yard/1.42 yards x 60 inches. The well-known Golec formula for fabric cover, as set forth in U.S. Patent 3,787,273, is the difference between 100 percent and the percent of air space, assuming regular twist yarns and maximum diameter per inch=28, where N=yarn number.Thus, warp cover=warp ends per inch/28w,; fill cover=fill picks per inch/28T2; the open area (fabric air space)=(l-warp cover)x(l-fill cover), and the % fabric cover=(l-0.0337)x 100=96.63%. This woven substrate was Accordingly, for this fabric, warp cover=96/28213=0.9509, fill cover=42/2823=0.313; air space=(1-0.9509)x(10.313)=0.0491 x0.687=0.0337 and the % fabric cover=(l-0.0337x 100=96.63%.This woven substrate was subsequently heat set and destretched in the apparatus shown in Figs. 4 and 5, to impart the required dimensional stability in the running or warp direction of the material of less than 6.5% elongation at 170 pounds per linear inch (pli) of width tensile using a standard unravel strip method of testing.

Briefly, this testing method involved cutting a 1-1/4 inch wide heat set sample to a warp length of 10 inches, with the outer warp yarns being unraveled to leave a 1 inch width. The sample was placed in an Instron Tensile Tester with the jaws set at a 5 inch gap using 3 inch and 2 inch face clamps. The jaws and chart were set at speeds of 2 inches/min. and 0.5 inch/min. respectively, in order to determine the elongation at 100 and 170 pli and the warp tensile strength at break pli.

The heat setting was attained by using the standard drying tenter apparatus of Figs. 4 and 5, and, which had a heating capacity of 500"F. This apparatus is manufactured by Marshall and Williams Corporation, Providence, Rhode Island.

The entrance to the oven is constructed so that the fabric was nipped at the "NIP 4" position (Fig. 4), thereby causing the longitudinal tension, inasmuch as the tenter frame (chain and clip assemblies 61) was set to travel faster than the variable speed driven nip rolls 54, 55.

Referring to Figs. 4 and 5 in particular, a 60 inch wide roll of the fabric was placed upon unwind roll 40, and then fed through the machine to, but not into oven 57. The oven then was heated to 440"F while the tenter frame (forming the dual chain and clip assemblies 61) was set at a width of 56 inches. The entrance of the tenter frame is so designed that it is self-adjusting as to the width of the entering cloth fabric.

Following this, the fabric 200 was fed through the entire length of machine 56 and rolls 67, 68 were closed at "NIP 5" position. Once the fabric has passed through this position, it then was wound on wind up roll 69. Next, the surface speed of rolls 54 and 55 was set at 16 surface feet per minute, while the exit speed of rolls 67, 68 as set at 21 surface feet per minute (the speed of chain sprockets 62, 63 being measured at 21.5 surface feet per minute). Finally, nip rolls 45, 46 and 47, 48, were closed at the "NIP 2" and "NIP 3" positions respectively.

Fifteen rolls (approximately 200 yards per roll) of fabric 200 were heat set and destretched successfully to an elongation of less than 6% at 170 pli (unravel strip test). The fabric was heated to about 440"F for about 1 minute because the oven was only about 25 feet long. In addition, markers, to determine width decrease, as well as length increase, were sewn into the fabric with the following results. The weftwise tension was sufficient to limit the average width decrease from the woven state through heat setting and stabilizing to 5%. The warpwise tension was sufficient to produce an average length increase of 4.3%. Hence, the warpwise and weftwise tension were sufficient to increase the fabric cover to 99.86%.This figure was determined from the foregoing formula after adjusting for the changes in ends and picks per inch caused by the average width decrease and length increase. Thus, 1.05x96=100.8 warp ends per inch; warp cover=100.8/28=0.998, and warp air space=1.000-0.998=0.002; likewise 0.957x42=40.194 fill picks per inch; fill cover=40.194/28\/23=0.299; fill air space 1.000-0.299-0.701; fabric air space=0.002x0.701=.0014=0. and and fabric cover=100-0.14=99.86%.

In order to compare the pertinent physical properties with a standard belt backing construction made of cotton, the following control was treated in the same manner as noted above except for heat setting. This control construction was a comparable roll of cotton drill, woven with 76 ends and 48 picks, 12-l/25 warp and 17" fill. This construction was subjected to a standard wash and dye process and dried in the normal way, producing a 4.8% width decrease.

The pertinent physical properties of each type of fabric are set forth below.

TABLE I Tensile pli % Elongation %Elongation Warp at 170 pli Warp at 100 pli Warp Polyester HS 346 5.9 2.3 Cotton Standard Wash and Dye 135 6.9 Note: Elongations at 170 pounds per inch were not compared because the cotton ruptured at less than 170 pounds per inch. However, one readily can see from the above Table that both the strength and the elongation characteristics of the inventive heat set polyester fabric were substantially superior to the cotton control fabric.

The polyester fabric 200 was subsequently cloth finished, as was the cotton control fabric, using a back fill and a back size of Rhoplex AC 604/CaCO2 and a front fill of phenolic/CaCO3 of the following formulations.

Back Fill and Back Size Formulation Wet Lbs. Dry Lbs. % Dry Basis AC 604 475.0 218.5 48.86 CaCO3 218.0 218.0 48.74 NH4SCN 4.5 4.5 1.01 Tamol (25%) 2.5 0.63 1.14 Sodium Carboxy methyl Cellulose (8%) 70.0 5.60 1.25 Water 66.6 Total 836.6 447.23 100.00 Note: The viscosity of the formulation, at 750F was 5,500 cps+500 cps, and the solids content was 53%.

Rhoplex AC 604 is the trademark for a thermosetting acrylic emulsion polymer supplied by Rohm & Haas Company, Independence Mall, West, Philadelphia, Pennsylvania 19105, and had a Brookfield viscosity at 250C of 20- 100 cps, a solids content of 46% and a pH of 9.5-10.5. This resin is described in the Rohm & Haas Technical Bulletin C-340 February 1972. The ammonium thiocynate crystals were used for catalysis of the AC 604 and were purchased from McKesson Chemical Company, 803 Walden Avenue, Buffalo, New York. The Tamol 731(25% solids) is the trademark for a dispersing agent also available from Rohm & Haas Company.The calcium carbonate (ground limestone) had a CO2 content of 43.88 + 0.43%, a specific gravity of about 2.74, an average particle size between 17 and 25 microns, as measured at the 50 /n point on a sedimentation curve, a white color, a particle size range such that not more than 35% by weight remained on a 220 mesh screen having an opening of 53 microns (USS), and freedom from organic impurities and inorganic trace elements such as SiO2, Fe2O3, Awl203, and clays. The vendor is National Gypsum Company, Philadelphia, Pennsylvania.

The sodium carboxymethyl cellulose was an anionic, water soluble thickening agent, having a pH of 7.0 at 2% solution, a solids content of 95 + 1%, and a viscosity of 25-30 cps, number 1 spindle at 60 rpm, using a Brookfield LVF viscometer.

The back fill and back size is a 1:1 ratio of AC 604/CaCO3 on a dry basis composition. The system is catalyzed with ammonium thiocynate in a 1:48 ratio based on dry AC 604. The wetting agent (Tamol 731), thickener (8% carboxymethyl cellulose), brown pigment and water are added to obtain a viscosity of 5,500 cps+500 cps at a temperature of 75"F. The total solids of the solution is 53% dry basis.

The viscosity will vary with the coating application method used, as is known by those skilled in the art. The knife on web system actually used requlres a viscosity of 5,500 cps in order to produce a satisfactory finish. However, if a flexible knife on roll method of application is employed (or an inverted knife as well), the viscosity can be dropped as low as 1,300 cps to obtain a satisfactory finish.

The back fill deposition is 3.5+0.5 dry pounds per ream (I ream equals 4809x 1 sheets). The back size composition, which is the same as the back fill, was deposited dry at 2.5+0.5 pounds per ream. As noted above, the viscosity will vary depending upon the method of application, i.e., knife or roll.

The front fill composition employed was a 1:1 ratio of a phenol formaldehyde resole and calcium carbonate on a dry basis. The viscosity was 1,300 cps + 150 cps at 90 F, with a solids content of 75%, by weight, dry basis. This composition had the following formulation.

Front Fill Formulation Wet Lbs. Dry Lbs.

P-Fl resin 500 345 50.70 CaCO3 333 333 48.93 Span 20 2.5 2.5 0.37 Furfural 67.9 Total 903.4 680.5 100.0 (Span is a Registered Trade Mark).

The P-F1 resin had a formaldehyde/phenyl ratio of 0.99, and contained ethylene diamene as the catalyst constituting 0.6% of the total charge. This catalyst was modified with furfural and shelacol constituting 4.6% and 2.0% respectively of the total charge. The physical properties of the resin were: pH=7.7+.2, specific gravity=1.120+0.025, solids content=69+3%, viscosity=1,400 cps+200 cps, and G.

E. Gel time at 1210C=20+2 minutes.

The CaCO3 was the same as noted above. Span 20 is a sorbitan monolaurate, used as a wetting agent and is available from McKesson Chemical Company, Buffalo, New York.

The furfural (furfuryl aldehyde) is a solvent thinner with a specific gravity of 1.165+0.005 at 20/20"C. This material may be obtained from Quaker Oats Company, Cleveland, Ohio.

The viscosity and solids may vary according to the method of deposition, as known to those skilled in the art, with the roll coating actually used requiring considerably less viscosity than if a knife coating were employed. For coarse grits, a roll coating does produce a satisfactory deposition, but for fine grit products, it may be necessary to knife coat such face or front fill composition.

The deposition used to achieve the satisfactory product was 8+2 pounds per ream of face or front fill.

As noted above, the heat set polyester woven fabric and the cotton control fabric were cloth finished in accordance with the foregoing description. It also is to be noted that an attempt was made to cloth finish non-heat set and destretched polyester fabric, but this was found to be impossible because of curling (tubing), i.e., rolling up of the selvage edges of the fabric toward the center of the fabric.

Hence, further efforts along this line were discontinued.

For the non-waterproof coated abrasive product produced in accordance with this Example, the polyester and cotton constructions were as follows: Polyester Cotton Backing Material 96x42 sateen 76x48 drills (as woven) (Standard in the Coated Abrasive Industry) Backing weight 17.0+0.7 15.7+0.7 Ibs/ream Ibs/ream Heat set and Yes Pull Down Only Destretched Back fill- 3.5+5 Ibs/ream 2.1 Ibs/ream AC 604/CaCO3 Polyester Cotton Back size- 2.5+0.5 Ibs/ream 2.1 Ibs/ream AC 604/CaCO3 Front fill- 7.0+0.5 Ibs/ream 7.2 Ibs/ream P-F Resole/CaCO3 Note: Everything else being the same, it was found to be impossible to deposit the same amount of back fill and back size on the cotton substrate as on the polyester, although the front fill met the specifications.

A comparison of the properties of these two filled fabrics is set forth below.

TABLE II Polyester Cotton (Heat set and (Pull Down Destretched) only) Warp Tensile: pli 472 254 % Elongation at 4.8 2.4 170 pli Elmendorf tear: Warp did not tear 693 Cross-warp (propagated across fill) Base Adhesion: 17.8 Embrittled Instronpli Note: No further work was done with the cotton because of embrittlement.

In preparing for the base adhesion test, the specific maker mix described below was applied to the face side of an 8 inchx 10-1/2 inch sample of each fabric with roll bars. This was repeated and a sandwich was made of the two samples. The sandwich was pressed through a laboratory padder for uniform contact. Following drying for 3 hours at 2000F, with a disc weight on top, the samples were stapled on three of the four sides, leaving one side to begin peeling. The samples then were cured for a time of about 16 hours at a temperature of about 225"F.

The cured samples were cut into one inch wide strips about 10-1/2 inches long in the machine direction using a cutting board and a one inch placement control on the Instron Tensile Tester. Next, the samples were peeled by hand until the peeled strips extended past the opposite end of each sample. A one inch strip was placed on a steel bar and clamped with the bar into the upper jaw of the Instron. The remaining peeled strip was placed in the lower jaw, thus causing 1800 peel. The jaws were secured shut and the Instron was run at a speed of 0.5 inches per minute. The steed was charted; the 0.5 inch per minute cross-head speed and the pound scale were also charted.

From the foregoing Table it is evident that the excellent tensile, acceptable elongation and excellent tear properties across the warp, and the fact that the polyester was not embrittled during the adhesion test, show substantial superiority of the inventive polyester fabric over that of the standard cotton control susbtrate.

Pre-Size Continuing with the inventive method, and as noted previously, a pre-size may be applied to enhance adhesion. This alternative step occurs prior to deposition of the maker coating. In the manufacture of the belts illustrated in Figs. 2 and 3, a presize was used and is denoted at 28 and 28a respectively.

The undiluted pre-size composition is a water soluble phenolic resin having a formaldehyde/phenol ratio of 1.01, and a 50% sodium hydroxide catalyst constituting 0.6% of the total charge. The properties are: pH=7.85+0.15; S.

G.=1.195+0.015, solids=70%+3%; viscosity=500 cps+l50 cps, gel at 1210C in 28+3 minutes.

This pre-size layer was applied by means of a two roll padder to a deposition weight of 4 pounds per ream, wet basis. The pre-size is subsequently dried to a tack free state.

Making Coat The maker solution was made up of the same resin system as the pre-size solution, but with the incorporation of CaCO3 and Span 20 for wetting. Thus, the composition has the following formulation.

Maker Formulation Wet Dry Pre-size resin 550 385 41.04 CaCO3 550 550 58.64 Span 20 3 3 0.32 Total 1,103 938 100.00 Note: Total solids content was 85.04% by weight, dry basis.

This maker system was roll coated to a deposition weight of 21 pounds per ream on a wet basis, and such maker coat is illustrated in Figs. 2 and 3 at 30 and 30a respectively.

Grain Deposition The belt matrix at this point was inverted so that the maker coat faced downwardly, whereupon grit 36 aluminium oxide grain was then propelled upwardly electrostatically and embedded in the fluid mass at about 62 pounds per ream. Following this, the grain coated article was subsequently dried to a tack free state, so that the embedded grit did not lose its orientation.

Size Coating Following curing the maker, the article was then coated with a size or sand size coat having the following composition.

Size Coat Wet Dry Pre-size resin 550 385 40.45 Cryolite 550 550.00 57.79 Span 20 3.75 3.75 0.39 Tamol 731(25%) 8 2.00 0.21 Nalco 123 * 2.00 - AttagelSO 11.00 11.00 1.16 Total 1,124.75 951.75 100.00 * Approximate, assumed to contain no solids.

The pre-size resin is described above. The synthetic cryolite had the following formulation.

Ingredients % By weight, Dry Basis Cryolite (Na3A I F) 91 .94.0 F 48.052.0 Al 13.015.0 Al203 2.06.0 Si 0.14-- 0.30 CaF2 0 0.04-- 0.09 Fe2O3 0.01-- 0.10 Free Moisture 0.05-- 0.12 Sieve Analysis 100 Mesh 0.1% maximum Thru 100, on 200 Mesh 1.0% maximum Thru 200, on 325 Mesh 5.0% maximum Thru 325 Mesh 95% maximum Note: The maximum pH value is 8.5, and this material may be purchased from Great Lakes Foundry Sand Company, Detroit, Michigan.

The descriptions of the Tamol 731 and Span 20 have been given previously.

Nalco 123 is the trademark for an anti-foaming agent for both defoaming and preventing foam build-up in resin filler mixes. It is a blend of synthetic organic chemicals and can be purchased from Nalco Chemical Company, Chesterland, Ohio. Attagel 50 (Registered Trade Mark) is a thickener for resin systems. It is an especially processed form of the mineral Attapulgite, an acicular-shaped magnesium aluminium silicate. It can be purchased from Meyers Chemicals, Inc., Buffalo, New York.

This size or sand size coat was applied by means of a roll system to a deposition weight of 29 pounds per ream, wet basis. The product then was roll cured.

Product Finishing At this point in the inventive process, the coated belt forming matrix was finished, wherein the matrix was slit to the desired width and length of the desired number of belts, which then were spliced to produce a belt having the general appearance shown in Fig. 1. During this finishing, it usually is necessary to flex the belt matrix prior to the splicing and slitting operations to facilitate handling.

Standard Comparison or Control Products In order to properly evaluate the performance of the belts made in accordance with the present invention, they were tested against two standard belts incorporating cotton backing material and constructed as follows.

Cotton Control 1 The greige cloth construction of the Cotton Control No. I, was a cotton drill, 76 ends by 48 picks, 12-1/2S warp and 17S fill. The width decreased 4.8% prior to back filling, after the drying procedure of the standard wash and dye process.

The cloth was subsequently back-filled employing a two roll padder with a solution having the following formulation.

Wet Pounds Dry Pounds Glue 300 300 50 Starch 300 300 50 Water 833 Steam 92 1Total 1,525 600 100 Note: Viscosity was 10,000 cps+1,000 cps at 1500F. The deposition was 4.0+0.5 pounds per ream.

The glue properties were: viscosity, 58 mP+3 mP's; gel, 135 grams+5 grams; moisture, l2%+l.5%; pH, 6.5+1.0; ASA, 5% maximum; grease, 2.5% maximum; foam, 20 seconds; grading-at least 50% must be coarser than U.S. Standard 20 mesh, with no more than 2% passing 100 mesh and not more than 1% on the 6 mesh.

The vendor is Peter Cooper Glue Company, Gowanda, New York.

The starch is a 50 fluidity thin boiling starch. It may be purchased from Hubbinger Company, Keouku, Iowa under the mark Reofilm 50 (Registered Trade Mark).

The face fill and back size were applied by means of a two roll padder using a 25% glue solution having a viscosity of 40+5 cps at 1500F. The solution had the following formulation. Wet Wet Glue 400 Water 1,216 Total 1,616 Note: Total solids were 25%.

The face fill deposition was 1.3+0.5 pounds per ream and the back size deposition was 1.0+0.5 pounds per ream. The glue was the same as that used in the back fill.

The backing was pre-sized with the P-F resole resin as previously described, with a deposition of 4.0 pounds per ream (wet).

The maker was then applied with a two roll padder to a wet deposition of 28 pounds per ream.

The maker formulation was as follows: Wet Dry P-F2 resin 275.0 176 18.57 P-F3 resin 275.0 213 22.48 CaCO3 550.0 550 58.04 Potassium Tri polyphosphate 5.5 5.5 0.58 Span 20 3.0 3.0 0.32 Total 1,108.5 947.5 100.00 Note: Total solids were 85.5%.

The P-F2 resin had a formaldehyde/phenol ratio of 1.76, with barium octahydrate catalyst constituting 2.24% of the total charge, and the properties were: pH=7.9f0.2; specific gravity=1.21+0.02; solids=64.0~2; viscosity=130 cps+35; water tolerance=100% minimum, G. E. gel at 1210C=12+1.5 minutes.

The P-F3 resin had a formaldehyde/phenol ratio of 1.82, with barium octahydrate catalyst constituting 2.24% of the total charge, and the properties were: pH=8.0f0.1; specific gravity=1.275+0.015; solids content=77.5* 2.5%; viscosity=3,500 cps+1,000 cps; water tolerance=75% minimum; G. E. gel at 121"C=9 minutes+2 minutes.

The potassium tripolyphosphate (a dispersing agent) was a clear and colorless solution, and it may be purchased from Chemical Sales, Buffalo, New York.

The aluminium oxide grit was deposited in the same way as previously described on the maker coat.

The grain so embedded was subsequently size coated, using a two roll padder applying a size coat having the following composition: Wet Dry P-F2 resin so 352 34.78 CaCO3 650 650 64.23 Tamol 371 10 10 0.99 Nalco Trace - Total 1,210 1,012 100.00 Note: Total solids content was 84%.

The same procedures followed previously were then followed with respect to the curing and product finishing operations.

Cotton Control 2 The cloth substrate for this cotton control product was the same as for Cotton Control 1, including the cloth finishing, except for the pre-size, which had the following composition.

Pre-Size Formulation Wet Basis Pre-size resin 60% Camelcarb (Registered Trade Mark) (CaCO3) 40% This pre-size was supplied by means of a two roll coater to a deposition weight of 5.25 pounds per ream, wet basis. The pre-size resin is that described above. The Camelcarb is a fine grain CaCO3. The CO content is in excess of 40%, and the CaCO3 content is in excess of 92%. The color is white; 99.5% by weight must pass through a 325 mesh screen (U.S.S.) and 70 /O must be finer than 15 microns. The vendor is S. A. Campbell and Co., Inc., Cleveland, Ohio.

The maker composition was the same as for the inventive product above, and was applied by rolls to a deposition weight of 21 pounds per ream, wet basis.

The size composition had the following formulation.

Wet Dry P-F4 resin 550.0 385 40.94 Cryolite 550.0 550 58.48 Tamol 731 5.5 5.5 0.58 Nalco Trace - Total 1,105.5 940.5 100.00 Note: The total solids were 85%. The cryolite, Tamol 731 and Nalco have been described above. The P-F4 resin had a formaldehyde/phenol ratio of 2.03 and contained 50% sodium hydroxide catalyst making up 1.5% of the total charge. The physicals were: viscosity, 350+100 cps at 250C; solids content, 70+3%, G. E. Gel at 121"C, 11+2 minutes; water tolerance, 500% minimum; pH, 8+0.2; specific gravity, 1.195+0.15. This size coating was roll coated to a deposition weight of 19 pounds per ream, wet basis.

Comparison Tests The polyester backed belt product in accordance with the invention then was tested as were the two standard products containing cotton backing. The belt size for both the polyester backed and standard products was two inches wide by 132 inches long. The following data was obtained.

Cut Data for 1018 Cold Rolled Steel Edge Test Number Cut Test Grams of Contacts Removed Polyester loaded Belt 8.5 955 Cotton Control 1 5 882 Cotton Control 2 3 884 These tests showed the base adhesion qualities (Edge Test), as well as stock removal capabilities (Cut Test). The polyester backed belts showed 2.8 times better base adhesion than the Cotton Control 2 and 1.7 times better base adhesion than the Cotton Control 1. It is believed that this is a result of the cloth finishing process, wherein thermosetting materials have been incorporated into the substrate to retain much of the original body, without embrittlement. On a percentage basis, the results showed the polyester backed belts to be 70% better than Cotton Control 1 and 167% better than Cotton Control 2.The capability of metal stock removal also is better in that the polyester backed belts are 8% better than both control products.

A unique capability of this non-waterproof heavyduty, all resin product, is that it has the strength and toughness to withstand being doubled upon itself across the warp, grain side being compressed, without shattering. It cannot be torn readily across the warp manually, in the crease produced during the doubling process. On the other hand, coated abrasive belts with plain cotton as a standard substrate and finished with both natural and thermosetting high polymers, and made into an all resin product, as were the two controlled products, will just not stand up to this type of treatment, but will shatter first.

In addition, the belts in accordance with the invention have been evaluated successfully in the field against competitive products, with the reports indicating at least a 75% success ratio ranging from 25% to 300% better in metal removal capabilities.

In some instances in the field, the polyester backed belts with aluminium oxide grain was found to be better than competitive products having incorporated in their coated abrasive belts premium grain composed of zirconia-alumina, that is generally and normally known to out produce the regular aluminium oxide abrasive belts in both edge tests and in grinding performance.

EXAMPLE 2 The 100% polyester sateen fabric, heat set and destretched, as well as cloth finished as in Example 1, was made into a waterproof product for use as a coated abrasive where such a product is immersed in a predominantly aqueous solution in order to carry out the grinding operation. While the various coating and product finishing steps were the same as those used for Example I, it was necessary to change the maker system so that the phenol-formaldehyde resin used to hold the grain did not lose its properties detrimentally when so used in an aqueous system.

Thus, the maker composition of this Example was as follows.

Maker Coat Formulation Wet Dry V Al 6164 resin 550 451 44.83 CaCO3 550 550 54.67 Span 20 3 3 0.30 Silane Z-6026 2.75 2 (Prox) 0.20 Total 1,105.75 1,006 100.00 Note: The solids content was 91%. The maker was deposited by means of a roll coater at 19 pounds per ream, wet basis, and viscosity was 2,000 cps. For viscosity adjustment two parts of ethylene glycol monoethylether were used for 3 parts of water.

The physical properties of the Al 6164 phenol formaldehyde resin were: solids content, 82+3%; viscosity, 5,000f1,000 cps; G. E. Gel at 1210C, 6+1 minute, and pH at 25"C, 6.7+0.3. This resin can be obtained from Borden Chemical Company, Bainbridge, New York. The Silane Z-6026 (an adhesion promoter) may be purchased from Dow Corning Corporation in Cleveland, Ohio.

The ethylene glycol monoethylether had a specific gravity of 0.928+0.505, and may be purchased from Commercial Chemicals Inc., Buffalo, New York.

Grit 36 aluminium oxide grain was applied as in Example 1 but at about 57 pounds per ream and subsequently sized, using a two roll coater as it is well known to those versed in the art. The size composition was as follows.

Size Formulation Wet Dry % Al 6164 resin 550 451 44.83 CaCO3 550 550 54.67 Span 20 3 3 0.30 Silane Z-6026 2.75 2.75 0.2 Total 1,105.75 1,006.75 100.00 Note: The physical properties of this size composition were: solids content, 91% viscosity, 2,000 cps; deposition, 29 pounds per ream, wet basis. The viscosity adjustment was the same as for the maker coat.

The sized belt forming matrix was then cured, flexed, slit to width and spliced in order to provide a waterproof product similar to that illustrated in Fig. 2, except that there was no pre-sizing required.

It is to be noted at this point that for both the non-waterproof product of Example 1 and the waterproof product of this Example 2, where a fine grit abrasive is employed (80 grit and finer), the front fill needs to be applied with a knife on web, rather than by a roll application. The back fill and back size remain the same. In this particular case, i.e., fine grit size, the front fill formulation is modified to the following.

Wet Dry Al 6164 resin 500 410 53.24 CaCO3 350 350 45.87 Span 20 3 j 0.39 Total 853 763 100.00 Note: Solids content was 89; viscosity was 3,250+250 cps at 900 F, and the composition was deposited at 10 pounds per ream, wet basis. The viscosity adjustment was made using the same solution as with the Al 6164 resin maker and size solution.

The cloth was dried to a tack-free state and thereafter further processed in the same manner as in Example 1 to produce the desired coated abrasive belts containing abrasives of 80 grit size and finer.

EXAMPLE 3 The polyester fabric was heat set and destretched as in Example 1 except that the apparatus of Figs. 6 and 7 was used. The knurled rolls had a surface speed of about 84 feet/minute, the tenter frame (i.e. chain and clip assemblies) had a surface speed of about 87 feed per minute, and the backing material was heated to about 440"F for about 1 minute because the oven was about 90 feet long. However, to increase pliability, the back fill and backsize steps were eliminated and replaced with a dip filling operation in order to produce a belt having a cross-section such as that illustrated in Fig. 3.

The dip fill was composed of a 20% phenol-formaldehyde resin/water solution having the following formulation.

Wet Dry Pre-size resin 3,000 grams 2,100 grams Water 7,500 grams Total 10,500 grams 2,100 grams Note: The solids content was 20%. The pre-size resin was as described above in Example 1.

The polyester substrate was immersed in this solution and subsequently squeezed between two rolls and dried. The dry add on was 1.3 pounds per ream.

The cloth thus treated was given a second dip application for a total of 2.8 pounds per ream, dry pickup. A face or front fill coat of 60/40 phenol-formaldehyde resin/calcium carbonate at 1300 cps+l00 cps at 900F was applied to the dip filled fabric to a dry deposition of 8+2 pounds per ream. This face fill was the same composition as employed in Example 1.

In order to compare the difference in processing between these two Examples, the following information is tabulated below.

Comparison to Physicals in Example 1 Tensile pli Elongation at 170 pli Polyester, BF, BS, FF 472 4.8% Polyester, dip fill, FF 428 4.3% As is evident, the physical properties of the dip filled polyester as compared to that in Example 1 are quite adequate. Next, the dip filled fabric was processed in the same manner as for Example 1 in order to produce belts having a grit size of 36 aluminium oxide grain in an all resin system. Following this, the product of this Example was compared to those recorded in Example 1, with part of the data being repeated, below.

Cut Data for 1018 Cold Rolled Steel Edge Test Number of Contacts Cut Test Grams Example 1 8.5 955 Example 3 6 918 Cotton Control 1 5 882 Cotton Control 2 3 884 From the data in the above table, it becomes evident that the cloth finishing plays a part in final performance because the dip filled product of this Example is not quite as good as the back sized, back filled product of Example 1. At the same time, the dip filled product is substantially superior to the Cotton Control 2 product. The edge test results of the above table are an indication of greater pliability in the dip filled product than in the back sized product, and this is an asset in areas where more pliability is a pre-requisite, so long as stock removal remains within acceptable limits.

EXAMPLE 4 The polyester fabric was heat set and destretched as in Example 3, but the double dip fill coat operation disclosed therein was replaced with a single dip to achieve satisfactory results where base adhesion is not a pre-requisite, as in Example 1, but a strong, tough backing is required. The single dip fill coat is composed of a 50% phenol-formaldehyde water solution having the following formulation.

Single Dip Fill Formulation Wet Dry Pre-size resin (Ex. 1) 10,000 7,000 Water 4,000 Total 14,000 The polyester substrate was immersed in the solution and subsequently squeezed between two rolls and dried. The dried add-on weight was 3i0.5 pounds per ream.

A front fill or face fill coat of 60/40 phenol-formaldehyde resin/calcium carbonate at 1300 cpsilO0 cps at 900F was applied to the dip filled fabric to a dry deposition of 8i2 pounds per ream, and the formulation of and the properties of such resin compound was the same as for Example 1.

Comparison of Physical Properties Tensile pli. Elongation at 170 pli Example I (control) 472 4.80/, Polyester BF, BS, FF Example 3 (control) Polyester double dip 428 4.3% and FF Polyester single dip 428 4.4% and FF The above comparison Table of physical properties shows that the single dip and double dip products are comparable, and quite adequate in comparison to the control product of Example 1 which had the back fill, back size and front fill coats.

The single dip filled cloth finished product was then processed to form belts in the same manner as set forth in Example 3, in order to produce a 36 grit aluminium oxide all resin product and resulting belts.

The product thus made was compared to the polyester control product as set forth below.

Cut Data 1018 Cold Rolled Steel Edge Test Number Grams of Steel of Contacts Removed Polyester single dip 16 679 Polyester BF, BS, FF (control of Ex. 1) 16+ 826 These above tabulated results show that the single dip filled product does not have quite the base adhesion of the polyester control product of Example 1. Also, these results indicate that the flat cut is better on the product which has more body, namely the product of Example 1.

At the same time, this single dip product has been successfully field tested as a SiC resin cloth on glass.

EXAMPLE 5 The 100% polyester sateen fabric heat set and destretched as in Example 3, and cloth finished as in Example 4 was made into a waterproof product for use as a coated abrasive belt, where such a product is immersed in a predominantly aqueous solution to carry out the grinding operation. In this case the maker system was changed, as in Example 2, so that the phenol-formaldehyde resin employed to hold the grain did not lose its properties detrimentally when used with such aqueous system.

The only other difference between the product of this Example and that of Example 4 was that a fine grit silicon carbide grain was employed. This grain had a size of 80 grit and was deposited at about 24 pounds per ream, and the belt product was evaluated in comparison to a control waterproof belt product of the invention in the same grit where the cloth finish was back filled, back sized and front filled.

The results in glass grinding were as follows: TABLE III Glass Grams Removed Inches Stretch Polyester waterproof control 126 3/32 Polyester two pass process (dip plus front fill) 130 2/32 These results show at least comparable cut and stretch during use of the two pass product in comparison to the polyester control, WHAT WE CLAIM IS: 1. A woven polyester containing fabric suitable for use as a backing material for a coated abrasive product, which fabric has been heat set under tension, whilst maintaining the desired width thereof, so that the fabric has a dimensional stability warpwise of less than 6.5 elongation at 170 pounds per linear inch of width tensile.

2. A fabric as claimed in claim 1 which is woven from 100% polyester staple fibres and the fabric cover being substantially 99.86%.

3. A fabric as claimed in claim 1 or 2 provided with a cloth finish including fill and front fill coats containing thermosetting resin.

4. A coated abrasive product comprising a backing of a fabric as claimed in claim 1 or 2, said backing having a cloth finish including a fill coat and a front fill coat each containing a cured thermosetting resin, and there being successive maker, abrasive and size coats over the front fill coat with each of said size and maker coats containing a cured thermosetting resin.

5. A coated abrasive product as claimed in claim 4 wherein the fill coat is a dip fill coat.

6. A coated abrasive product as claimed in claim 5 wherein the cured thermosetting resin contained in the dip fill coat and that contained in the front fill coat are each a cured phenol formaldehyde resin.

7. A coated abrasive product as claimed in claim 4 wherein the fill coat is a back fill coat.

8. A coated abrasive product as claimed in claim 7 which additionally includes a back size coat and containing a cured thermosetting resin.

9. A coated abrasive product as claimed in claim 8 wherein the cured thermosetting resin contained in the back size coat and that contained in the back fill coat are each an acrylic polymer.

10. A coated abrasive product as claimed in any one of claims 7 to 9 wherein the cured thermosetting resin contained in the front fill coat is a cured phenol formaldehyde resin.

I 1. A coated abrasive product as claimed in any one of claims 4 to 10 wherein the cured thermosetting resin contained in the maker coat and that contained in the size coat is a cured phenol formaldehyde resin.

12. A coated abrasive product as claimed in any one of claims 4 to 11 wherein there is a pre-size coat containing a cured thermosetting resin between the front fill coat and maker coat.

13. A coated abrasive product as claimed in claim 12 wherein the cured thermosetting resin contained in the presize coat is a cured phenol formaldehyde resin.

14. A coated abrasive product as claimed in any one of claims 4 to 13 in the form of an endless belt.

15. A method of making a fabric as claimed in claim 1, comprising maintaining a woven polyester containing fabric under both warpwise and weftwise tension whilst maintaining its desired width and whilst heating the fabric to a temperature and for a time sufficient to provide the woven fabric with a dimensional stability

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (34)

**WARNING** start of CLMS field may overlap end of DESC **. The only other difference between the product of this Example and that of Example 4 was that a fine grit silicon carbide grain was employed. This grain had a size of 80 grit and was deposited at about 24 pounds per ream, and the belt product was evaluated in comparison to a control waterproof belt product of the invention in the same grit where the cloth finish was back filled, back sized and front filled. The results in glass grinding were as follows: TABLE III Glass Grams Removed Inches Stretch Polyester waterproof control 126 3/32 Polyester two pass process (dip plus front fill) 130 2/32 These results show at least comparable cut and stretch during use of the two pass product in comparison to the polyester control, WHAT WE CLAIM IS:

1. A woven polyester containing fabric suitable for use as a backing material for a coated abrasive product, which fabric has been heat set under tension, whilst maintaining the desired width thereof, so that the fabric has a dimensional stability warpwise of less than 6.5 elongation at 170 pounds per linear inch of width tensile.

2. A fabric as claimed in claim 1 which is woven from 100% polyester staple fibres and the fabric cover being substantially 99.86%.

3. A fabric as claimed in claim 1 or 2 provided with a cloth finish including fill and front fill coats containing thermosetting resin.

4. A coated abrasive product comprising a backing of a fabric as claimed in claim 1 or 2, said backing having a cloth finish including a fill coat and a front fill coat each containing a cured thermosetting resin, and there being successive maker, abrasive and size coats over the front fill coat with each of said size and maker coats containing a cured thermosetting resin.

5. A coated abrasive product as claimed in claim 4 wherein the fill coat is a dip fill coat.

6. A coated abrasive product as claimed in claim 5 wherein the cured thermosetting resin contained in the dip fill coat and that contained in the front fill coat are each a cured phenol formaldehyde resin.

7. A coated abrasive product as claimed in claim 4 wherein the fill coat is a back fill coat.

8. A coated abrasive product as claimed in claim 7 which additionally includes a back size coat and containing a cured thermosetting resin.

9. A coated abrasive product as claimed in claim 8 wherein the cured thermosetting resin contained in the back size coat and that contained in the back fill coat are each an acrylic polymer.

10. A coated abrasive product as claimed in any one of claims 7 to 9 wherein the cured thermosetting resin contained in the front fill coat is a cured phenol formaldehyde resin.

I 1. A coated abrasive product as claimed in any one of claims 4 to 10 wherein the cured thermosetting resin contained in the maker coat and that contained in the size coat is a cured phenol formaldehyde resin.

12. A coated abrasive product as claimed in any one of claims 4 to 11 wherein there is a pre-size coat containing a cured thermosetting resin between the front fill coat and maker coat.

13. A coated abrasive product as claimed in claim 12 wherein the cured thermosetting resin contained in the presize coat is a cured phenol formaldehyde resin.

14. A coated abrasive product as claimed in any one of claims 4 to 13 in the form of an endless belt.

15. A method of making a fabric as claimed in claim 1, comprising maintaining a woven polyester containing fabric under both warpwise and weftwise tension whilst maintaining its desired width and whilst heating the fabric to a temperature and for a time sufficient to provide the woven fabric with a dimensional stability

warpwise of less than 6.5% elongation at 170 pounds per linear inch of width tensile.

16. A method as claimed in claim 15 wherein the fabric is heated at a temperature of 400 to 4600F for a time of 0.75 to 2 minutes.

17. A method as claimed in claim 16 wherein the temperature is 4400F and the time is from I to 1.5 minutes.

18. A method as claimed in any one of claims 15 to 17 wherein the fabric to be subjected to said temperature and said tension is a fabric woven from 100% polyester staple fibres in a sateen weave and with a fabric cover of substantially 96.63%, and wherein the fabric cover is increased by said method to subtantially 99.86%.

19. A method as claimed in any one of claims 15 to 18 wherein the warpwise tension is sufficient to provide an average length increase of more than 4 /,, and the weftwise tension is sufficient to limit the average width decrease to 5%.

20. A method as claimed in any one of claims 15 to 19 additionally comprising the step of providing the dimensionally stabilised fabric with a cloth finish including a fill coat and a front fill coat each containing a thermosetting resin.

21. A method of producing a coated abrasive product incorporating the method of claim 20 and including coating the cloth finished fabric with successive maker, abrasive and size coats with the maker and size coats each containing a thermosetting resin, and curing the coated material to produce said abrasive product.

22. A method as claimed in claim 21 wherein the fill coat is a dip fill coat.

23. A method as claimed in claim 22 wherein the thermosetting resin contained in the dip fill coat and that contained in the front fill coat are each a phenol formaldehyde resin.

24. A method as claimed in claim 21 wherein the fill coat is a back fill coat.

25. A method as claimed in claim 24 wherein there is additionally applied to the back fill coat prior to curing, a back size coat containing a thermosetting resin.

26. A method as claimed in claim 25 wherein the thermosetting resin contained in the back size coat and that contained in the front fill coat are each an acrylic polymer.

27. A method as claimed in any one of claims 24 to 26 wherein the thermosetting resin contained in the front fill coat is a phenol formaldehyde resin.

28. A method as claimed in any one of claims 21 to 27 wherein the thermosetting resin contained in the maker and size coats is a phenol formaldehyde resin.

29. A method as claimed in any one of claims 21 to 28 wherein a pre-size coat containing a thermosetting resin is applied between the maker and size coats.

30. A method as claimed in claim 29 wherein the thermosetting resin contained in the pre-size coat is a phenol formaldehyde resin.

31. A woven polyester containing fabric substantially as hereinbefore with reference to the accompanying drawings.

32. A coated abrasive product substantially as hereinbefore with reference to the accompanying drawings.

33. A method as claimed in claim 15 for making a fabric substantially as hereinbefore with reference to the accompanying drawings.

34. A method of producing a coated abrasive product substantially as hereinbefore with reference to the accompanying drawings.