DE1694861C3 - - Google Patents

Description

Subject of the German patent =. 1,282,970 is the use of epoxy resin Fornimassen, an epoxy resin of bisphenol A, and: contain conventional curing agent for the manufacture of abrasive fabrics for wet grinding as Appretii ^r - and Impirägniermasse, optionally for the back of these tissues, which in addition contains an epoxy resin ;. obtained from bisphenol and internally plasticized by looking at castor oil.

A further development of this use has been found to result in a substantially improved one Abrasive fabric sheet comes when the included Abrasive grain backing made from regenerated cellulose fibers, especially of the polynosic type Fibers, consists and wherein

a) the warp thread sized and finished and the size and first finish without boundary layer is firmly bonded,

b) the weft thread has an initial finish.

The invention therefore relates to the method specified in claim 1.

In the present invention, the abrasive grain backing fabric thus prepared is then applied provided with a further finish and a back coating, as in the German patent 1 282 970 has already been described. Otherwise, all embodiments of this patent application can be improved by the present invention.

Cotton fabrics are primarily used for the production of high-quality abrasive fabrics, which are used in the form of abrasive belts for machine sanding in the metal and woodworking industries. As a fabric construction comes z. B. a twill fabric (2: 1) in question with a thread count per cm of 34 / 20.5 made of cotton yarns of thicknesses 20/28 m / g; the fabric weight of the desized fabric is about 235 g / m ^a . Such a fabric has a breaking load of about 23 kp / cm in the warp direction with an elongation at break of 17% auli, while the corresponding tensile strength values for the weft are at a breaking load of 10 kp / cm

Equipped Raw fabric tissue (desized) 35
Middle Basis weight 315 g / m ² 236 g / m ² Tear resistance in the warp direction 40 kgf / cm 23 kgf / cm 30 denial of breakage 6.5 "" 17 "" Tear resistance in the weft direction ... 12.6 kgf / cm 10 kgf / cm Elongation at break IQ 0 / Q 0 '
° 0

It can be seen that the greater elongation originally present in the warp direction compared to the weft direction during the tearing process was significantly reduced 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 partially relocated the stretch existing in the warp direction in the weft direction. A fiber material based on cotton has the ideal conditions for strongly stretching it in the warp direction when it is wet. In the case of cotton fibers or fabrics, the elongation increases at the beginning of the tearing process, even with little force, and then hardly increases again with further tensile stress, i.e. it is possible to equip cotton fibers and accordingly also cotton fabrics with largely little stretch in the warp direction by means of a wet stretching process.
The disadvantage of using raw abrasive fabrics based on cotton is that they have to be subjected to a relatively complex, prepared drying and wet finishing process before they can actually be finished, ie finished. The reason for this is that high-absorbency carrier fabrics are required for the production of abrasive fabrics, since only these have the prerequisites for perfect adhesion of the finishing agent and binding agent to the fabric.

But cotton contains growth accompanying substances of a waxy and fat-like nature, which have a considerable Disturb the wettability and absorbency of the tissue and only through intensive,

I 694

costly Appreturvorbehandlungen as lintschlichten alkttKsch.es scouring and scouring - JE w s in connection with numerous rinsing processes - can be £.

There has been no lack of attempts Shabu _o "s rayon materials, ie on the basis of rlenerierter cellulose to produce. As far as it concerns low-quality abrasive cloth sheets for hand sanding processes, this has been practiced with success for many years. So far, however, it has not yet 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 operators. This is related to the fact that% ate cellulose fabric of the conventional type .5 oeeen over cotton fabrics have a greatly reduced wet strength compared to the corresponding strength values in the dry state. Furthermore, their swelling value - better water retention soegs - is significantly higher than with cotton fibers. * ° DeTwSeren is known that in the case of cellulose fiber types there is largely proportionality between the action of force 3 occurring elongation; it is therefore not possible during the wet processing * stretch the Zel'woll-S by mechanical stretching to _n "™

The latest developments in the field of However, cellulose fibers have led to cellulose materials which 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 such cellulose materials well above that of Cotton lies, while its elongation behavior and the tearing process in the dry as in the

The disadvantages outlined above are those according to the invention Can avoid proceedings. .

The core creeping is not in the essay »Sizing agents for the textile industry .. vjuj Ench

P. Frieser in the journal ADN * _c ^SI "™. \ ^J *! J! [Gang 1961, No. 10, pp. 505 to 512; No. 11.5». 504DuO //.

and No. 12, pp. 617 to 622.

An abrasive grain carrier fabric web produced in this way as the starting material for the new Äcn egg tissue web has the great advantage that the soft fabric finish firmly adhered to the core-sized Warp thread and the drawer iesi

connected is. chi-ifWnrn

In the production of the present abrasive grain carrier fabric web for the "inventive Schi" f. Grain fabric web gives you the advantage of this First finishing no high amounts of first finishing agent must be applied because the warp thread

is already core-sized. In addition, the new arrangement in the first processed sheep grain carrier fabric web a high est.z.tat d «e« r eraelu

As a size for the warp thread or be Core size is, for example, brew-oa - ^ J Starch and starch derivatives synthetic resin mfBa «by

l ^ anaten ^ ^^^ Γ ^ - alcohol, ^^ vinyl acetate, acrylic-N.ri.-B ^ en-styrene-

Copolymers in the form of, π _B e _netzU n _esm ktel dispersions and corresponding ^Be ^ ^to " ^g ^ ^e '; e.g. naphthasulfonates, acrylic derivatives or ethoxy

adducts. p ^ ivmr-e -iuf base

Preferred core rights and poles. ^ uf Ba s

from acrylates and their ^De " ^vdt " degraded ^^^^

sSES

fabric of regenerated viscose staple fiber, in particular the Polvnosic group to use as Schlcifrohgewebe, d S for ^P ihr'er natural cleanliness should be treated much less complicated in the emergency as a normal cotton fabric.

see g!

from 15 to 45 C.

a solver

65 to 200 C

Xylene. Ethyl _halide perchlorates.

Conveniently, it is imperative that they be desized. In addition, abrasive backing fabrics have been generated from «cr Cellulose, especially from the Polynoc.c group, compared to disarmed cotton fabrics em aa Much greater suction and take, dadiireh

rsr: r ^ ^through 7 ^the - ^ neUcnckn

First finish advantages achieved.

first _{phen (jlgrund} .

own, as well

Zellulose-, insbeso.de, = Pol, nos, c-Fa, = r ", £ t found that the above J ^ _c ^ ta _U * veSS. or "can be achieved in a bilateral reach process. This innovation ^ ma ».

The first finished abrasive grain carrier fabric web becomes an abrasive fabric web by further finishing processed, as described in detail in the utility model 1 904 919.

example 1

A warp yarn of size Nm 28/30 made of regenerated cellulose fiber (Polynosic type) is placed in a sizing trough with a recipe consisting of

80 parts by weight due to acid degradation

open-minded strength
3 parts by weight of ethoxy adduct
917 parts by weight of water

Core layered and dried on a cylinder drying machine and then into a raw abrasive fabric interwoven. The raw abrasive cloth produced in this way is given an initial finish without desizing, consisting of

sized, and then dried and fixed in an air duct at 140 ^{° C.} After weaving, the raw abrasive fabric is immediately treated with a finishing solution consisting of, without desizing

50 parts by weight
100 parts by weight

50 parts by weight

3 parts by weight

797 parts by weight

animal hide glue

(300 sheets, 100 mp)

a copolymer

Acrylate dispersion

kaolin

Naphthalene sulfonate

water

impregnated and dried with simultaneous stretching with a lateral penetration of about 11.5% and fixed. Then it is according to the utility model 1 904 919, Example 6, on the back and front side coated and then further treated in the manner described there. Compared to the known abrasive fabrics, the abrasive grain fabric 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 placed in a sizing trough with a moth consisting of

120 parts by weight of reactive copolymer

Acrylate Disperison

5 parts by weight of a water-soluble copolymer of 30% acrylic acid, 70% butyl acrylate

875 parts by weight of water

120 parts by weight
5 parts by weight

20 parts by weight
60 parts by weight
20 parts by weight

2 parts by weight
773 parts by weight

reactive copolymer

Acrylate dispersion

of a copolymer of 30%

Acrylic acid and 70% butyl

acrylate

toluene

kaolin

Dimethyloldihydroxyethylene

urloff

Magnesium chloride

water

impregnated and stretched at 140 ° C - the fabric wraps around in width 11.5% on - and fixed. Then it is according to the utility model 1 904 919, Example 6, on the Coated front side and then further treated in the manner described there. It becomes an abrasive grain weight Preserved with excellent grain adhesion.

To prove the technical progress, the abrasive grain fabrics obtained in this way are put on a belt sander Clamped and tested in the test grinding process.

In this test grinding process, an abrasive fabric produced according to the invention was provided with a conventionally sized, then not desized and then conventionally finished Abrasive backing fabric compared in terms of abrasive testing.

With a constant pressure load, the grinding was carried out from a defined iron pipe. Further became the surface of the abrasive fabric after the test grinding process with regard to sanding and Visually inspected grain eruption. As a measure of value, the achieved grinding time applies up to the complete Breaking out of the abrasive grain. Furthermore, the adhesive strength of the abrasive cloth finish was measured by application a phenolic resin intermediate layer and lamination of this sample using the same phenolic resin Sheet checked. The sample was cured and, after air conditioning, the peel strength was determined and the point of peeling is determined

Belt grinder Outbreak of grain Tissue after Peel test

Peeling takes place

Conventionally sized abrasive fabrics not desized and conventionally impregnated

Newly sized abrasive cloth impregnated with an inventively sized and finished product and a second finish, as described in German patent specification 1 282 970, coated ...

The tests show that the abrasive grain fabric web after the present innovation in multiple Regard is present in a surprisingly improved manner.

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

F i g-1 shows the abrasive grain carrier 8, where 1 denotes 1 minute

12 minutes

6 kg

15 kg

between sizing and finishing

between phenolic resin and apprctu

core sized and first finished warp thread dai represents and 2 illustrates the first interpreted weft thread.

F i g. FIG. 2 shows the structure of the abrasive grain fabric treated according to the invention, FIG. illustrated abrasive grain carrier illustrates un

with the new fabric: rstappretur provided is. The abrasive grain binders 6, consisting of the base binder 4 and the size binder 5, are clearly shown. As an abrasive grain layer Γι, for example, silicon carbide in the Grit gradations customary in the abrasive industry useful. In addition, the filler-free molding compound according to the invention is also available as an intermediate layer 9 applied, reproduced. Through this intermediate layer 9 the technical characteristics of the

Abrasive cloth is significantly improved, as its tough-elastic properties make it a suitable transition from flexible carrier fabrics to the hard synthetic resin bond of the abrasive grain carrier. 7 shows the according to the innovation, filler-containing molding compositions as the backside screed of the impregnated according to the innovation Carrier fabric.

The molding compound used according to the invention as an applied filler-free coating compound is mti 9 designated

1 sheet of drawings

Claims (2)

Patent claims: I. A process for producing abrasive fabric webs using epoxy resin molding compounds according to patent 1282970, characterized in that a carrier fabric made of regenerated cellulose fibers is used, the warp thread of which is kerigied, and without prior desizing with first »o finishing agent, which is in an aqueous medium contains emulsified organic solvent 65-200 ⁰ C, a solvent for the warp yarn located on the sizing is at temperatures of 15 to 45 ° C and a swelling agent, has been appretiert. 2. The method according to claim 1, characterized in that a carrier fabric made of polynosic Cellulose fibers are used. Elongation at break of 8% (strip tensile test on textile fabrics according to DIN 53857 The result was divided by 5 in order to convert from the 5 cm wide test strip to 1 cm). Since abrasive cloth is made up as abrasive belts in their direction of use, that is the Ken or In the longitudinal direction of the fabric, only a very low degree of elongation is allowed, otherwise the There is a risk that the sanding belts will move under the influence of those occurring during the sanding process Extend tensile stress excessively and run down from the contact disk of the grinding machine, is it necessary such ·; Tissues in the wet state during the appre'urtechnischen finishing to subject a stretching process, which is achieved by the incorporation of finishing agents after drying of the Tissue is fixed. A finished abrasive backing fabric on the basis of the above-mentioned R - has z. B. the following properties (for comparison, the right column shows the corresponding raw fabric listed):