DE1694861A1 - Abrasive fabric sheet for wet sanding qualities - Google Patents

Description

Additional patent application to R 4 608 IVc / 39 b Abrasive fabric sheet for wet sanding qualities In the German patent application R 3 ( 6o8 IV e / 39 b becomes the use of epoxy resin molding compounds containing an epoxy resin made from bisphenol A and the usual hardeners for the production of abrasive fabrics for wet sanding as a finishing and impregnating compound, optionally for the back of these fabrics, these additionally containing an epoxy resin obtained from bisphenol and converted by reaction internally plasticized with castor oil.

As a further development of this use it has been found that you get a significantly improved Sehleifgewebebahn @, if the included Abrasive grain backing made from regenerated cellulose fibers, especially of the Polynesian type Fibers, consists and wherein a) the warp thread sized and finished, and the The size and the first finish are firmly bonded without a boundary layer. b) the weft has an initial finish.

In the present invention, the abrasive grain backing web thus prepared is used then provided with a further finish and a back coat, as already described in the German patent application R 36 608 IV c / 39 b is. In addition, all embodiments of this patent application by the present invention can be improved.

For the production of high quality abrasive fabrics in the form of Sanding belts for = machine sanding in the metal and wood processing industry diverse uses of thread, cotton fabrics are primarily used. As a fabric construction, z. B. a twill fabric (2: 1) in question with a Number of threads per cm of 34 / 20.5 made of cotton yarns with a thickness of 20/28 m / g, the weight of the fabric of the desized fabric is approx. 235 g./m2. Such a fabric has in the warp direction has a breaking load of approx.

23 kp / cm with an elongation at break of 17%, while the corresponding Tear strength values for the weft direction at a breaking load of 10 kp / cm an elongation at break of 8%. (Strip tensile test on textile fabrics according to DIN 53-857. The result obtained was divided by 5 by the 5 cm wide test strips to be converted to 1 cm.

Since abrasive fabrics are made up as abrasive belts in their direction of use, that is, the warp or longitudinal direction of the fabric, they may only have a very low elongation capacity, otherwise there is a risk that the abrasive belts will become excessively long under the influence of the tensile stress occurring during the grinding process run down from the contact disk of the grinding machine, it is necessary to subject such fabrics to a stretching process during the finishing process in the wet state - which is fixed by the incorporation of finishing agents after the fabric has dried. A finished abrasive backing fabric based on the above-mentioned type of cotton fabric has e.g. B. the following properties: (for comparison, the corresponding raw fabric is listed again in the right column). Finished raw fabric - fabric (desized) Average basis weight 315 g / m2 236 g / m2- Tear strength in Warp direction 40 kp / em 23 kp / cm Elongation at break 695-% 1.7 Tear strength in Direction of vision 12.6 kg / cm 10 kg / cm Elongation at break 20% 8 It can be seen that the greater elongation originally present in the warp direction compared to the weft direction was significantly reduced during the tearing process by the stretching and finishing process, while the elongation in the weft direction increased significantly - in other words: it was due to the stretching and finishing process Finishing process: the stretching in the warp direction partially moved into the weft direction. A fiber material based on cotton has ideal conditions to keep it in when wet Advancing the warp direction significantly. In the case of cotton fibers or weaving takes the elongation at the beginning of the ganges already with little force to then hardly to increase with further tensile stress, i.e. it is possible> cotton fibers and accordingly also tree wool fabric by a wet greek process in the warp direction to equip with little stretch. Disadvantageous for the use of abrasive raw fabrics on the The basis of cotton is that this is a relatively complicated the prepared dry and wet finishing process. must be thrown before they are actually expelled equips, ie can be finished. The reason for this lies in the fact that one is used for the manufacture of abrasive cloths highly absorbent carrier fabric is required, as only this exposures for perfect adhesion of the finishing and Have binders on the fabric. But cotton contains wax and growth accompanying substances of a fatty nature, which - a considerable disturbance of the wetting- bring about the ability and absorbency of the tissue and only through intensive, expensive finishing pretreatments, such as Desizing, * alkaline decoction and cupping - each in connection with numerous rinsing processes - be removed don hönnen.ö- There has been no shortage of attempts to -wollmatcrialicn, ie on the basis of regenerated Zolluloee: to manufacture. Insofar as it is a matter of minor term abrasive cloth sheets for commercial processes, this has been practiced successfully for years. So far, however, it has not been possible to use cellulose fabrics for high-quality abrasive grain carrier fabric webs that are suitable for the production of abrasive fabric tapes for machine grinding own when dry.

Furthermore, their swelling value - better water retention capacity - is essential higher than with cotton fibers. It is also known that in cellulose fiber types there is largely proportionality between the force applied and the elongation that occurs; it is therefore not possible to mechanically damage the cellulose fabrics during the wet finishing Stretching to fix with little stretch.

Have the latest developments in the field of pulp fibers but led to cellulose materials that differ in their dry as well as in their wet tear behavior very close to that of cotton. You can even find that the dry strength of such cellulose materials is significantly higher than that of cotton, while you Expansion behavior during the tearing process in the dry as well as in the wet state largely corresponds to that of cotton fibers. At this stage of development of cellulose fibers are fibers made from regenerated cellulose, in particular the Polynosic group, which is a specific term within the Zellwoll-Tochnologie represents. (To prevent all possible fiber types from regenerated celluloso are referred to as Polynoic, the Association International Polynosis (AIP) made certain demands of a technical nature, those of polynosial fibers must be fulfilled). It would be of general: advantage in the manufacture of abrasive cloth Cellulose tissue made from regenerated viscose wool, in particular of the polynosie group, as Use abrasive raw cloth, as this is essential because of its natural cleanliness The wet equipment is easier to handle than normal cotton fabrics.

The disadvantage is that the conventional warp thread-sized looper fabric, due to the conventional sizing, anti-adhesive character compared to the have conventional finishing binders to be applied later and are therefore conventional absolutely have to be desized. In addition, abrasive backing fabrics have made of regenerated cellulose, especially the Polynosic group compared to desized = cotton fabrics have a much higher absorbency and therefore take a lot more finishing agent on, which in turn makes the finishing process more expensive.

Furthermore, the tear resistance of normally finished abrasive raw fabrics becomes on the base before. regenerated cellulose fibers, especially polynosia fibers, strongly reduced.

It has now been found that one can overcome the disadvantages outlined above can be avoided if, according to patent application R 36 6o8. IV c / 39 b an abrasive grain carrier fabric web made of regenerated cellulose fibers, especially of the polynosic fiber type, used, where a) the warp thread sized and finished and the size and first finish is firmly adhered without a boundary layer and b) the weft has an initial finish.

A special embodiment of the abrasive grain carrier fabric web is characterized in that the warp thread is provided with a core size (core size - see magazine ADHÄSION) Born 1961, No. 10 - pages 505-512, and No. 11 - pages 564 - 577 and No. 12 - Pages 617-622 in the article on "Sizing Agents for the textile industry "v. Erich P. Friesen) In a further embodiment is the abrasive grain backing fabric web for the abrasive fabric web according to the invention characterized in that the first finish located on the warp thread and weft thread by first finishing with a first finishing agent which is in an aqueous medium contains emulsified organic solvent, which at temperatures of 15 _ 1; .5 ° C a swelling agent and over 65 - '200 ° G a solvent for those on the warp thread is located, is arranged Irrorden.

A abrasive backing fabric web produced in this way as the starting material for the new abrasive fabric web has the great advantage that the abrasive fabric first finish firmly attached to the learning-sized warp thread and the weft thread is.

In the manufacture of the present abrasive grain backing fabric for the abrasive grain fabric web of the invention has the advantage that in the First finish no high amounts of first finish agent have to be applied, because: the warp thread is already core sized. In addition, the new Arrangement in the first finished abrasive grain carrier fabric web a high; elasticity this achieved.

As a size for the warp thread or preferably core size is for example usable: degraded starch and starch derivatives, synthetic resins based on isocyanates, homo- and / or copolymeric acrylic compounds (butyl, methyl acrylates) ', polyvinyl alcohol, Polyvinyl acetate, acrylic-nitrile-butadiene-styrene copolymers in the form of solutions od-er @ dispersions and appropriate wetting agents, e.g. B. naphthalene sulfonates, Acrylic derivatives or ethoxy adducts.

Preferred core sizes are polymers based on acrylates and their derivatives as well as acid-degraded starch products and fatty acid condensation ethoxy adducts. Possible finishes for the warp thread and for the weft thread are, for example: animal hide glue and / or reactive and non-reactive copolymeric acrylate solutions or aqueous dispersions, polyisocyanates, polystyrene, N-methylol compounds of urea and its derivatives, aldehydes and its derivatives ;, sulfone compounds, Phenol formaldehyde resole resins, polyvinyl alcohol, acetate and chloride in the form of Dispersions and solutions, epoxy and polyester resins as well as starch, starch derivatives and ethoxy adducts, these organic solvents emulsified in the aqueous medium contain, which is a swelling agent at temperatures of 15 - 450C and above 65 - 2000C is a solvent for the size on the warp thread. Suitable emulsifiable organic solvents are, for example, toluene, xylene, ethyl acetate, White spirit, trichlorethylene, .perchlorethylene. Preferred finishing agents are self-crosslinking copolymeric acrylate dispersions, especially copolymers based on butyl and Ethylaerylat-Basis-like methyl methacrylate in dispersion or solvent-dissolved Shape.

The use of the preferred first finishing agents gives the following particular advantages, since the crosslinking acrylate dispersions have good adhesive properties as the first finish to the Ph.enol base resins to be applied later, and this also avoids embrittlement of the fabric. In addition, the first finished soft grain carrier fabric web can be provided with the same first finish on both sides of the web, as is achieved by a dipping process or a double-sided coating process. This innovative, first-finished abrasive grain carrier fabric web is processed into an abrasive fabric web by further finishing, as described in detail in utility model 1 904 919. EXAMPLE 1 A warp yarn of size Nm, 28/30 made of regenerated cellulose fiber (Polynoeia type) is made up of 3 parts by weight of ethoxy adduct consisting of> 8C parts by weight of starch dissolved by acid degradation in a looping trough 917 parts by weight of water core-sized and dried on a cylinder dryer and then woven into a raw abrasive fabric. The Sehleifroh fabric produced in this way is without desizing with an initial finish, consisting of 50 parts by weight of animal hide glue - 300 sheets, 100 mp) 100 parts by weight of a copolymeric acrylate dispersion 50 parts by weight of kaolin 3 parts by weight of naphthalene sulfonate 7-97 parts by weight of water - impregnated and dried and fixed with simultaneous stretching with a sideways penetration of approx. 11.5%. Then it is according to the utility model 1 904 9199 Example 6 ,. coated on the back and front and then further treated in the manner described there. Compared to the known sole cloth fabrics, the abrasive grain cloth produced in this way is characterized by excellent elasticity and good grain bonding.

Example -2 A warp yarn made of regenerated cellulose fibers (polynosic type) of Nm 26 is in a size box with a liquor consisting sup 120 G4w.-Toileri reactive copolymeric acrylate dispersion 5 G $ W. parts water soluble copolymer composed of 3% Acrylzäu 0 re 70 y6 butyl acrylate 875 parts by weight of water is chlorinated and then dried and fixed in an air duct at 140 ° C. After weaving. the abrasive raw fabric without desizing immediately with a finishing solution consisting of - 120 parts by weight of reactive copolymeric aorylate dispersion 5 parts by weight of a copolymer of 30 aerylic acid and 70% butyl acrylate 20 parts by weight toluene 60 parts by weight Kaolin 20 parts by weight of dimethyloldihydroxyethylene urea 2 parts by weight of magnesium chloride 773 parts by weight of water impregnated and stretched at 140 ° C. - the fabric jumps in width by 11.5% and is fixed. It is then coated on the front in accordance with utility model 1 904 9199, example 6, and then further treated in the manner described there. An abrasive grain cloth with excellent grain adhesion is obtained.

As proof of technical progress, the Abrasive grain fabric stretched on a belt grinding machine and in the test grinding process tested.

13 (: i dic: scm test grinding process, an abrasive fabric made according to the invention was used with a conventionally cut, not desized, and then afterwards Conventionally finished abrasive backing fabrics compared using test grinding technology. With a constant pressure load, the cut was made from a defined iron pipe carried out. Furthermore, the surface of the abrasive cloth after the test grinding process visually assessed with regard to sanding and grain breakage.

The benchmark for value is the grinding time achieved until the abrasive grain has broken out completely. The adhesive strength of the abrasive fabric texture was also tested by applying a phenolic resin intermediate layer and laminating this sample to sheet metal using the same phenolic resin. The sample was cured and, after air conditioning, the peel strength and the peel point were determined. Belt grinding peeling peeling machine grain test takes place outbreak Fabric according to: Conventionally sized 6 kg between 1 minute Abrasive cloth not sizing and conventional - sizing and lent impregnated finish According to the innovation, sneaked 15 kg between 12 minutes tete abrasive cloth with phenolic resin inventive finishing and finishing treatment and finish impregnated ned 'and second finish, as in the German patent Ft 38 608 IVc / 39 b loading wrote, coated The tests show that the abrasive-grain fabric web is surprisingly improved in several ways according to the present innovation.

The abrasive grain fabric web according to the innovation is illustrated by the drawings made clear.

Figure 1 shows the abrasive grain carrier 8, where 1 is the core-sized and Figure 2 illustrates the first finished warp thread; and Figure 2 illustrates the first finished weft thread.

Figure 2 shows the structure of the newly treated 8 abrasive grain fabric, wherein 8 illustrates the abrasive grain carrier shown in Figure 1 and with the renewal fabric i #: r btappretur is provided. The abrasive grain binders 6 consisting of the base binder 4 'and the top binder 5 are clear reproduced. As an abrasive grain layer 3, for example, silicon carbide is in the abrasive industry usual grit gradations usable. In addition, according to the innovation, it is filler-free Form dimension: additionally applied as an intermediate layer 9, shown. Through this Intermediate layer 9, the technical properties of the abrasive cloth are essential improved, as their tough-elastic properties make them a suitable transition of flexible backing fabrics for hardening synthetic resin bonding of the abrasive grain backing. Number 7 shows the filler-containing molding compositions according to the invention as a backside screed of the impregnated carrier fabric according to the innovation. The newly used Molding compound as applied filler-free @ coating compound is with the; Digit 9 designated.

Claims (2)

Claims 1. Use of epoxy molding compounds according to the patent. . . (Patent application R 38. 608 IVc / 39 b), whereby the tissue contained is made from reGenerated Cellulose fibers, in particular of the polynosic fiber type, consists, and wherein a) the Kettfaderi sized and finished and the size and first finish is firmly bonded without a boundary layer and b) the weft thread is a first finish wearing. 2. Use according to claim 1, wherein the warp thread is provided with a core size for the purpose specified in claim 1. 3Use according to claim 1 or 2, wherein the first finish located on the warp thread and the weft thread by finishing with a first finishing agent, which is organic solvent emulsified in the aqueous medium, holds, which at temperatures from -15 to 45 ° C a swelling 0 of a solution for the medium unj over 65 - 200o # The size located on the warp thread is arranged for the purpose specified in claim 1.