FR2526801A1 - PROCESS FOR CURING ABRASIVE COMPOSITIONS CAPABLE OF CURING UNDER ACID ACTION - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS FOR CURING COMPOSITIONS FOR ABRASIVES, COMPOSITIONS WHICH INCLUDE AN ACID CURABLE BINDER AND, AS CURING CATALYST, A COMPOUND CAPABLE OF RELEASING SULPHONIC ACID UNDER THE ACTION OF RADIATION. AFTER THE COMPOSITIONS HAVE DRYED, EXPOSED THEM TO RADIATION AND CURED. MASK CURING CATALYZERS ARE FOR EXAMPLE ORGANIC COMPOUNDS OF THE FOLLOWING TYPES: (CF DRAWING IN BOPI) THESE MASK CATALYZERS, WHICH DO NOT CAUSE ANY CURING DURING THE DRYING STAGE, ARE OF VERY GREAT INTEREST FOR ACID CATALYSIS OF THE HARDENING OF ABRASIVE COMPOSITIONS.

Description

The present invention relates to a method for curing compositions

  abrasive hardenable under the action of an acid,

  compositions which are based on a hardenable resin under

  an acid and containing a hardening catalyst

  than. By "grinding tool" or "grinding tool" is generally meant an assembly forming a whole which is constituted by the union of a hard abrasive material in grains, possibly

  also a support element or an armature, with a binder.

  According to their structure, grinding or grinding tools can be arranged in two main groups, namely grinding wheels, such as grinding bodies, ring grinding wheels.

  stems and flexible abrasives on flat supports

  niformes. For soft abrasives on planiform substrates the most diverse synthetic resins are used as binders

  but above all, among these, phenoplasts or aminoplas-

  as well as the alkyd-melamine resins.

  to make them, the support is coated with a thin layer of

  After this, the binder is dried, then cured and heated to a point where the grains of the abrasive material are sufficiently anchored during the subsequent treatment and can not be separated from the granular material. This is done by applying a second layer consisting of a finishing binder, usually loaded with calcium carbonate, which layer must also be subjected to a heat treatment to be cured. several hours If these drying times and hardening are so long it is particularly because the binders involved are generally in the form of dispersions

  in order to eliminate, in the first place,

  This is because water is dispersed and water is released during curing, especially when phenol-formaldehyde resins are used as binders, which must also be removed.

  requires high temperatures.

  To accelerate the hardening of curable resins

  with acids it is certainly known to resort to cataract

  acid curing lysers, for example organic acids

  such as p-toluenesulphonic acid (in this connection, see Houben-Weyl, Methoden der organi- schen Chemie, Volume 14/2, 4th edition (1963), page 238, or DE 2,406,992) In the manufacture of abrasives based on

  binders that can be hardened by acids, it is not pos-

  In order to accelerate the curing step, it is also possible to use such acids as catalysts, since these cause, as soon as the drying step is complete, premature curing of the resin or the formation of troublesome bubbles due to water included in the resin

  or products generated by condensation.

  To speed up drying and hardening, we also

  proposed in the first published specification of the patent application DE 2 444 525, a method of manufacturing abrasives in which binders are used instead of the usual aqueous binders

  based on phenolic resoles in polar organic solvents

  This process does not, however, completely satisfy the

conditions laid down.

  That being so, the present inventor has found that it is pos-

  sible, by means of certain so-called "masked" catalysts which decompose rapidly when exposed to light at

  during the hardening step by giving sulfonic acids

  free, accelerate a lot and shorten the curing operation In addition hardening can then be performed

at low temperature.

  The great advantage of these curing catalysts is that, because they are inactive compounds in step

  drying, they do not cause a premature curing

  binder, which would be troublesome It becomes possible,

  for the first time, to use acid catalysis in the dura-

  curing abrasive compositions.

  The subject of the present invention is therefore a method for

  harden abrasive compositions containing a hardened binder

  acid and, as a curing catalyst, an acid

  organic sulphonic acid released under the action of light, pro-

  characterized in that the abrasive compositions, after

  have been dried, exposed to light and hardened.

  It is considered particularly interesting

  as masked curing catalysts, the organic compounds

  compounds corresponding to one of the formulas (I) and (II): ## STR2 ## and (R 1) n (I) (<i) in which: n represents the number 1 or the number 2, R 1 represents an unsubstituted phenyl or naphthyl radical

  or carrying, for example, 1, 2 or 3 radicals taken in

  seems constituted by -Cl, -Br, -CN, -NO 2, the alkyls in

  C 1 -C 2, C 1 -C 4 alkoxy, phenoxy radicals, toluene

  loxy, phenylthio and tolylthio, C 1 -C 8 alkylthio,

  -SCH 2 CH 2 OH, C 1 -C 4 alkylsulfonyls, phenylsulfonyl

  alkyl, C 2 -C 4 alkoxycarbonyls, C 1 -C 4 alkylamino, C 2 -C 4 dialkylamino, phenyl-CONH-, C 1 -C 4 alkyl radicals CONH and radical benzoyl, R 1 may further represent a radical

  anthryl, phenanthryl, thienyl, pyridyl, furyl, indole,

  lyl or tetrahydronaphthyl, R 2 and R 3 each independently represent hydrogen, unsubstituted C 1 -C 8 alkyl or, for example, an -OH, -Cl, C 1 -C 4 alkoxy radical; 1-C 4, - CN,

  C 2 -C 5 alkoxycarbonyl, phenyl, chlorophenyl, alkyl-

  C 7 -C 10 phenyl or C 7 -C 10 alkoxyphenyl, or a benzoyl, and furthermore R 3 may represent an unsubstituted phenyl or a carrier, for example, of a radical -Cl, C 1 -C 4 alkyl , C 1 -C 4 alkoxy or C 1 -C 4 alkylthio, C 2 -C 8 alkoxycarbonyl, -CN,

  alkylaminocarbonyl radical with C 1 -C 4 alkyl, a radical

  cal phenyl-NH-CO or -CONH 2, or R 2 and R 3 together with the carbon atom to which they are attached a C 4 -C 6 cycloalkyl ring, R 4 represents: when N is 1 , C 1 -C 18 alkyl, unsubstituted phenyl or bearing, for example, halogen, C 1 -C 12 alkyl, C 1 -C 4 alkoxy, alkylcarbonylamino alkyl radical, in C 1 -C 4, of a radical

  n-carbonylamino, a -NO 2 or benzoyl, a naphthalene

  unsubstituted tyl or carrier for example a halogen,

  of a C 1 -C 12 alkyl or a C 1 -C 4 alkoxy, a cycloalkyl

  C 5 or C 6 alkyl, a C 7 -C 9 aralkyl, a campheryl, -CF 3, -CC 13, -F or -NH 2, and when N is 2 a - (CH 2) radical m wherein m denotes a number from 2 to 8, or an unsubstituted phenylene or naphthylene radical or bearing, for example, a C 1 -C 12 alkyl, R 5 represents an unsubstituted phenyl or naphthyl radical or bearing 1, 2 or 3 radicals; taken in the set together

  by -Ci, -Br, C1-C12 alkyls, phenyl, alcohols

  C 1 -C 4 xy, phenoxy, benzyloxy, C 1 -C 8 alkylthio, phenylthio, -SCH 2 CH 2 OH, alkylcarbonylamino-C 1 -C 4 alkyl, benzoylamino, dimethylamino and the like. benzoyl, or R 5 is anthryl or phenanthryl, R 6 is hydrogen, -OH, C 1 -C 4 alkoxy, -O Si (CH 3) 3, -OCOCH 3 or C 1 alkyl -C 8 unsubstituted or phenyl-bearing, R 7 represents hydrogen, unsubstituted C -C alkyl

7 1 8

  or carrier of a phenyl, -CN, benzoyl, alkylcarbonyl

  C 1 -C 4 nyl, C 2 -C 5 alkoxycarbonyl or phenyl, and R 8 represents hydrogen, unsubstituted C 1 -C 8 alkyl or bearing a -OH, -Cl or phenyl, unsubstituted phenyl or bearing a radical -OH, -Cl, alkyl

  C 1 -C 4 or C 1 -C 4 alkoxy, C 2 -C 6 alkenyl, phenyl-

  C 8 or C 9 alkenyl, furyl, thienyl, -CC 13, or saturated or unsaturated C 5 or C 6 cycloalkyl, or R 7 forms with R 5, with R 6 or with R 8 and with skeleton

  carbon to which they are attached, a pentagonal or hexagonal

  gonal that contains from 1 to 5 of the following groups:

  -CH 2-, -CH (CH 3) -, -C (CH 3) 2-, -O-, -S-, -SO-, -SO 2-, -CO-,

-N (CO-C-C 4 alkyl) and -N (COC 6 H) -.

-NC C 06 H 5)

  When R or R 5 represents a phenyl or a naphthyl

  C1-C12 alkyl carrier, the latter is linear or branched

  and is for example a methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-tubyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl or dodecyl radical, but more particularly methyl when R 1 or R 5 is a phenyl or naphthyl

  carrier of a C 1 -C 4 alkoxy, the latter is, for example, a radical

  methoxy, ethoxy, propoxy or tert-butoxy.

  When R 1 or R 5 is a phenyl or naphthyl bearing a C 1 -C 8 alkylthio this is linear or branched and is

  methylthio, ethylthio, n-propylthio, isopropyl

  pylthio, n-butylthio, sec-butylthio, tert-butylthio, pentylthio, hexylthio, heptylthio or octylthio, but more particularly methylthio.

  When R 1 represents a phenyl or naphthyl radical

  a C 1 -C 4 alkylamino or a C 2 -C 4 dialkylamino, the substituent in question is, for example, a methylamino radical,

  ethylamino, propylamino, n-butylamino, dimethylamino or diethyl

  ylamino. When R 1 is a phenyl or naphthyl radical carrying a C 1 -C 4 alkylsulfonyl, this substituent is, for example, a

  radical methylsulfonyl, ethylsulfonyl, propylsulfonyl, butyl-

sulfonyl or tert-butylsulfonyl.

  When R 1, as a phenyl or naphthyl radical,

  substituted as an alkylcarbonylamino radical whose

  kyle contains from 1 to 4 carbon atoms this substituent is by

  for example, a methyl-, ethyl-, propyl or n-butyl -CONH- radical.

  When R 4 is a phenyl radical bearing as substituent an alkyl-CONH alkyl radical C 1 -C 4, this substituent is

  for example, a methyl-, ethyl-, propyl or n-butyl -CONH- radical.

  When R 1 is a thienyl, pyridyl or furyl radical,

  indolyl or tetrahydronaphthyl, all iso-

  However, the following isomers of position are preferred: 2-thienyl, 3-pyridyl, 2-furyl, 3-indolyl and

1,2,3,4-tetrahydro-6-naphthyl.

  As C 1 -C 8 alkyls, R 2, R 3 R 6 and R 8 are linear or branched alkyls, but preferably alkyls

  linear C 1 -C 4, such as methyl, ethyl,

propyl and n-butyl.

  C 1 -C 4 alkoxy which can carry a C 1 -C 8 alkyl

  represented by R 2 or R 3, or that a radical may be

  nyl or naphthyl represented by R 4, or which may represent R 6 is for example a methoxy, ethoxy, propoxy or tert-butoxy radical. When a C 1 -C 8 alkyl represented by R 2 or R 3 bears as substituent a C 7 -C 10 alkylphenyl or a C 7 -C 10 alkoxyphenyl, this substituent is, for example, a

  methyl-, methoxy-, ethyl-, methoxy-, tert-butyl radical

or tert-butoxy-phenyl.

  When a phenyl R 3 carries a C 1 -C 4 alkylthio, the latter is, for example, a methylthio, ethylthio radical,

propylthio or tert-butylthio.

  When R 2 and R 3 together with the carbon atom to which they are bonded form a C 4 -C 6 cycloalkyl this is for example a ring of cyclopentane, cyclohexane or

  cycloheptane but more particularly a cycloheptane nucleus

  hexane. Case where N is 1: As C 1 -C 18 alkyl, R 4 is a linear or branched alkyl, for example a methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl or hexyl radical; , heptyl, octyl, nonyl, decyl, 2-ethylhexyl, 6-alkyl, dodecyl,

  tert-dodecyl, tridecyl, tetradecyl, hexadecyl or octadecyl.

  When R 4 is a phenyl or naphthyl carrier

  of a C 1 -C 12 alkyl this alkyl is linear or branched.

  As C 5 or C 6 cycloalkyl, R 4 is a radical

cyclopentyl or cyclohexyl.

  As a C 7 -C 9 aralkyl, R 4 is for example a

  1-phenylethyl, 2-phenylethyl or benzyl radical.

  As camperyl, R 4 is the campheryl-10 radical.

  Case where N is equal to 2: When R 4 represents a radical - (CH 2) m it is, for example, an ethylene, propylene, butylene or pentyl radical;

hexamethylene.

  When the radical ph 6 nylene or naphthylene carries a

  C1-C12 alkyl is linear or branched.

  When the different benzene rings that may contain the radicals R 1, R 3, R 4, R 5 and R 8 bear radicals other than hydrogen atoms, this substitution takes place in

  ortho, in meta or para, but more particularly in para.

  When R 6, R 7 or R 8 represents a C 1 -C 8 alkyl carrying a phenyl it is for example a benzyl radical

or phenylethyl.

  As a C 1 -C 4 alkylcarbonyl radical, R 7 is, for example, a methyl, ethyl or propyl radical.

tert-butylcarbonyl.

  As the C 2 -C 5 alkyl alkoxycarbonyl, R 7 is

  for example a methoxy-, ethoxy-, isopropoxy-, butoxy-

or tert-butoxycarbonyl.

  The C 1 -C 4 alkyl or C 1 -C 4 alkoxy radical which can carry a phenyl R 8 is, for example, a methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, methoxy or ethoxy radical. ,

  n-propoxy, isopropoxy, n-butoxy or tert-butoxy.

  As C 2 -C 6 alkenyl, R 8 is, for example, vinyl, propen-1-yl, propen-2-yl, isopropenyl, buten-2-yl, isobutenyl, penten-2-yl, hexen-2-yl or hexene-5-yl, but more particularly a vinyl radical,

isobutenyl or propene-1-yl.

  As C 8 or C 9 phenylalkenyl, R 8 is a radical

  cal styryl or 3-phenylpropenyl, more particularly sty-

Ryle.

  As furyl radical or thienyl R 8 can be considered

  However, all the isomers of position are preferred.

furyl-2 and thienyl-2.

  As unsaturated C 5 or C 6 cycloalkyl, R 8 is, for example, a cyclopenten-2-yl radical, cyclohexen-1-yl

or cyclohexene-3-yl.

  The hardening catalysts which correspond to formulas (I) and (II) in which: N is 1,

  R 1 represents an unsubstituted phenyl or bearing, for example,

  chlorine or methyl, methoxy, methylthio, phenylthio, SCH 2 CH 2 OH or benzoyl, R 2 is hydrogen or C 1 -C 4 alkyl, R 3 is hydrogen or C 1 -C 4 alkyl or R 2 and R 3 together with the carbon atom to which they are attached form a cyclohexane ring, R 4 represents a C 1 -C 8 alkyl, an unsubstituted or alkyl-bearing phenyl or naphthyl radical C1-C12, or a campheryl, R5 represents an unsubstituted phenyl or bearing a chlorine, a C 1 -C 4 alkyl, a C 4 alkoxy, a radical alkali -SCH 3 or phenyl, R 6 represents -OH or C 1 -C 4 alkyl, R 7 represents C 1 -C 4 alkyl or phenyl, and R 8 represents H, C 1 alkyl -C 4, a furyl or -CC 13, or R 7 and R 8 together and with the carbon atoms that

  carry them a core of cyclohexane.

  We particularly appreciate the catalysts of

  which correspond to formulas (I) and (II) in the

  which N is equal to 1, R 1 and R 5 each represent a radical

  phenyl, p-tolyl or p-methylthiophenyl, R 2 represents hy-

  wherein R 3 represents a methyl, isopropyl, n-decyl or benzyl radical, R 4 represents a phenyl, p-tolyl or p-n-dodecylphenyl radical, R 6 represents -OH, R 7 represents -CH 3 or

phenyl, and R 8 is -H.

  The compounds of formula (I) are known or can be prepared by known methods, for example by reaction of the corresponding hydroxyl compounds of formula (A):

0 R 2

It i 2

R 1 C C OH (A)

  R 3 with one equivalent or one half equivalent of the corresponding mono or di-sulfonic acid chlorides of formula (B): R 4 (SO 2 Cl) n (B) in the presence of a base (see in this connection Journal of the Chemical Society Perkin I, 1981, page 263), or by reaction of the corresponding brominated derivatives of formula (C):

R C C-R (C)

1 C

  Br with one or half equivalent of the silver salts of the corresponding mono- or disulfonic acids of formula (D): (Ag 3 Snt -R 4 (D) for example according to the method indicated in the Journal of Organic Chemistry of the Ud SSR, Vol. 8, page 2166, (1972) In the formulas (A), (B), (C) and (D) the symbols R 1 to R 4 as well as

  n have the meanings given above.

  The starting compounds of formulas (A), (B), (C) and (D) are known compounds which can be prepared by known processes, for example those described in Houben-Weyl's work. entitled Methoden der Organischen Chemie: Vol. V / 4, pages 171-189 for the compounds of formula (C), volume IX, pages 411 and 563, for the compounds of formula (B), and for the compounds of formula (A) , the following places of literature: A 526, 143, 164 (1936), Am Soc 76,

  4402 (1954) and Z Obsc Chim 34, 3165 (1964).

  The compounds of formula (II) are known or can

  be prepared by known methods, for example by reaction

  corresponding epoxide compound of formula (E): OR II 17 R 8

R -C-C C (E)

  with an equivalent of the monosulphonic acid derivative

  of formula (F) or with a half equivalent of the disulfonic acid derivative of formula (G):

(F) HO 3 S-R 4-SO 3 H

(G)

R 4 SO 3 H

  for example according to the methods described in Ber Deutsch Chem. Ges 69, 2753 (1936) or in J Chem Soc 1949, 315, or by reaction of a corresponding hydroxyl compound of formula:

O R R

He 6 18

R C-C CH

I I

R 7 OH

  with a monosulphonic or disulphonic acid chloride of formula R 4 -SO 2 C 1 or Cl O 2 SR 4 -SO 2 Cl, according to the process indicated in the first published specification of the patent application DE 1,919,678 in the formulas ( E), (F) and (G) the symbols R 5,

  R 6, R 7, R 8 and R 4 have the meanings which have previously been

data.

  The epoxy compounds of formula (E) which are required can be prepared by known methods, for example by chlorination of the corresponding compound of formula (II):

5 C CH 2 R 7 (H)

  which is thus converted into the corresponding chlorinated derivative of formula (K):

O

I

R 5 C CH R (K)

  C1 which is then condensed with the corresponding aldehyde of formula (L):

R 8 C H (L)

  in order to obtain the corresponding epoxy compound of formula (E) for this purpose see Chem Soc 75, 2042 (1953) 1, or alternatively by an aldol reaction of the corresponding compound of formula (H) with the corresponding aldehyde of formula (L), which leads to the corresponding compound of formula (M): OR II 17 / R 8

R 5 CC CX (M)

R 5c c-Cx.

  compound which is then converted, for example by means of hydrogen peroxide, into the corresponding epoxy compound of formula (E) see in this regard J Chem Soc, 79, 928 (1901)

  and Org Syntheses 60, 88 (1981), for the aldolysis reaction.

  and Org Chem 28, 250 (1963) and Org Syntheses 55,

  (1967), for the formation of epoxy compounds.

  In the formulas (H), (K), (L) and (M), the symbols R 5, R 7 and R 8 have the meanings given above.

  The compounds of formulas (F) and (G) may be

  prepared by known methods, for example by those which are

  described in Houben-Weyl, Methoden der Organi-

  schen Chemie, volume IX, pages 347 and 435 respectively.

  It is also in accordance with the present process to use, in addition, other masked curing catalysts.

  may be, for example, c-methylol-benzol

  such as those described in the first fasci-

  published cicle of patent application DE 1,919,678 of benzoyl-4

  4-phenyloxo-2-dioxathiolan-1,3,2 (according to the first fasci-

  published patent application DE 2 842 002) as well as Nsulfonyloxyimides such as those described for example

  in European Patent Application 58,638.

  The curing catalysts considered in the pre-

  of this invention are added to the resins in a sufficient quantity

  health for curing The amount needed depends no

  only the nature of the resin but also the temperature

  The curing catalyst is generally used in an amount of from 0.1 to 10% by weight, preferably from 0.5 to 5% by weight, relative to the amount of curing. Solvent-free resin Mixtures of such curing catalysts can also be used. Acid hardenable binders for abrasive materials can be considered resins whose

  Hardening is accelerated by acid catalysts.

  These are above all phenoplasts and aminoplasts, such as products resulting from the condensation of formaldehyde with phenol, resorcinol, cresol, xylenol and their mixtures, urea, anilines or melamnine. Instead of formaldehyde, other aldehydes, such as

  as acetaldehyde, furfural or acrolein.

  Phenolic resins and hardenable aminoplasts

  by acids are described in detail in "Methoden der Orga-

  nischen Chemie ", Houben-Weyl, volume 14/2, 4th edition (1963),

pages 193 to 302 and 319 to 400.

  The acid-curable resins can also be

  be modified melamine resins, including resins

  etherified, esterified or otherwise modified melamine salts, for example alkyd-melamine resins, as well as acrylic, polyester or alkyd resins The binder may also consist of several hardenable resins

  in acidic medium, of identical nature or of different natures.

  It is also possible to use mixtures of different

  phenolic substances such as those described by

  example in the first published booklet of the application for

vet EP 12 409.

  Phenol-formaldehyde resins are highly preferred,

  more particularly the condensation products phenol-for-

  water-soluble, slightly alkaline to neutral type maldehyde, which has become very important When using aqueous liquid alkaline resins it is good to

  neutralize before adding the curing catalyst.

  Phenolic resins are particularly preferred.

  aqueous formaldehyde (so-called uresol varieties) that can be

  made neutral to slightly acidic (p H 4 to 6).

  Binders can be solutions or dispersions

  In addition to the abrasive material and the curing catalyst, they may contain fillers and additives, such as those commonly used, in an organic solvent, preferably in aliphatic alcohols, or in water. in the abrasive products industry, for example viscosity index improvers, thickeners, dispersants, additives improving the mechanical and thermal properties of abrasives, as well as

adhesion adjuvants.

  Abrasive materials or abrasive grains are used

  very hard substances with differing granularities

  The following materials are used mainly for corundum removal or silicon carbide. Other granular materials include zirconium oxide, boron carbide, boron nitride and quartz. garnet, glass, various metal powders, such as powders of Si, Cu, Ag, Ni and

of metal alloys.

  As fillers and additives, mention may be made, for example, of graphite, molybdenum disulphide, sideropyrite, potassium sulphate, barium sulphate, cryclite, iron sulphide, sodium chloride, magnesia and calcium oxide. , calcium fluoride, calcium carbonate, kaolin, glass fibers as well as various plastics, such as vinyl chloride / vinylidene chloride copolymers, polyvinylidene chloride, PCV, or various halides, sulphates, sulphites or mixtures of

* these, or other known charges in the

  for polishing and grinding.

  The binders may also contain small amounts of

  Examples of special additives, such as co-initiators and spectral sensitizers, include benzol and its derivatives, benzil and its derivatives, and

  disubstituted or trisubstituted acetophenones in

  anthracene or thioxanthone, as well as colo-

organic ingredients.

  List of resins or binders, abrasive materials,

  loads and additives which have just been given are not

  restrictive and is merely intended to illustrate the

this invention.

  The abrasive compositions which comprise: for the finishing binder (A) from 30 to 70% by weight of filler 70 to 30% by weight of r 6 sol (80% by weight in water) are very much preferred. ) from 1 to 5% by weight of water of 0.2 to 2% by weight of a curing catalyst, and for the base binder (B) of 2 to 20% by weight of filler (s) of 80 at 98% by weight of resole (at 80% by weight in water) of 1 to 5% by weight of water of 1 to 4% by weight of a catalyst,

  provided that the sum of the quantities of the four con-

  The composition of the composition is always 100% by weight.

  As already mentioned, the flexible abrasive manufacturing process comprises two steps, namely the drying step of the abrasive composition and the subsequent hardening step. During drying, the solvent used or the water is evaporated

partially or totally.

  During the curing step that follows the binder is crosslinked to such a point that the grain of abrasive material is

  anchored with sufficient strength during further processing

  This anchorage has an important

  capital importance for the quality of the final product For this purpose it is customary to harden at a relatively high temperature,

  for example 130 C or more, and for 1 to several hours.

  On the other hand, when using catalysts

  In accordance with the invention, the curing operation can be carried out at relatively

  and in shorter times, for example at

  below 100 C, preferably between 60 and

   C, and in a time of 1 to 200 minutes. These relatively low curing temperatures and these times of

  shortening, which is advantageous when applying the process of the invention, are of very great technical importance, for example in the case where substrates containing water are used, which makes it possible to eliminate an annealing further 4 in a humid atmosphere to recover the flexibility In addition one can thus realize a

energy saving.

  Another advantage of the process according to the invention is that the storage stability of the abrasive compositions is not impaired, although these compositions contain a

  curing catalyst In addition the hardening catalyst

  It does not come into action during the drying stage and causes the binder to harden only during the light exposure step, during which it releases

its sulphonic acid Ve.

  The irradiation of the resin is preferably carried out

  by means of ultraviolet radiation: for this purpose, a large number of suitable industrial devices are available today. These include medium pressure, high pressure or low pressure mercury vapor lamps, as well as luminescent tubes whose emission maxima lie

  between 250 and 400 nm The irradiation times required

  of the thickness of the resin layer, the degree of charge of the abrasive composition, the luminous intensity of the lamps and the distance to which they are located.

  abrasive in the form of a usual thick layer required for

  site, in common UV irradiation devices, an exposure time of a few seconds to a few minutes

  from this time the latent catalyst undergoes a

  tochemical and generates free sulfonic acid.

  If photosensitizers are added to the resin, it is also possible to irradiate with daylight lamps. The known photosensitizers are, for example, condensed aromatic hydrocarbons, such as perylene, aromatic amines (such as those which are

  described, for example, in US Pat. No. 4,069,054) or

  cationic or basic agents (such as those described

  for example in US Patent 4,026,705).

  The hardening catalysts applicable according to the invention

  They can also be used for further processing: for this purpose a second layer of finishing binder, usually containing fillers, such as calcium carbonate, is applied and cured by exposure to light and by

  In this way, the hardening is also accelerated.

  the finishing binder and curing is reduced.

  As a result of hardening, it may be necessary, if necessary

  to perform annealing in a humid atmosphere Others

  stages of development by which one passes during the manufacture

  abrasives are carried out in the usual way.

  The process according to the invention is particularly suitable

  good for the manufacture of flexible abrasives on

  planiform ports, for example on abrasive fibers, such as vulcanized fibers, abrasive fabrics, papers

  abrasives as well as combinations of papers and fabrics.

  The method is furthermore suitable for the manufacture of grinding wheels, in particular abrasive bodies, annular grinding wheels, grinding wheels, grinding wheels, cylindrical grinding wheels or grinding wheels.

straight bush mills.

  The following examples illustrate the process using specific compositions according to the invention.

  Parts and percentages are by weight.

  Example 1: Study of the anchoring of the abrasive grain and the

  hardening of the base binder in the presence of

  Applicable curing lysers according to the invention In an MS 7215 aqueous phenol-formaldehyde resin (product of Ciba Geigy, dry extract: 77% by weight, aqueous solution, H 4.5, viscosity: 2.5 to 3 Pa S 25 molar ratio of phenol to formaldehyde = 1: 1.2) is mixed 30% with

  weight (relative to the solids content of the phenol-formaldehyde resin)

  hyde) of a solution containing 10% by weight of the catalyst in methylpentyl ketone With the aid of a doctor blade of 200 Vm is applied

  on a sheet of aluminum the solution of phenol-formaldehyde resin

  hyde thus obtained (thickness of the dry film: from about 40 to 50

  pm), and then cover with corundum.

  treats the corundum in an elongated V-shaped hopper,

  the slot-shaped opening is covered by a metal sieve

  The hopper is mounted on a vibrator to coat

  rindon we put the vibrator on and we pass below

  of the hopper, at a steady speed, the aluminum sheet

  green of the resin (the amount of corundum applied is 400 to 600 g per m 2) Then, to eliminate water, place the f * | This is done, the sheet is irradiated for 5, 10 and 15 minutes under Philips TLK (R) 40/09 luminescent tubes at a temperature of 50 ° C. distance of 15 cm, irradiation during which the catalyst used according to the invention releases an organic acid which catalyzes the curing of the binder. After having then hardened at 90 ° C. for 20 minutes, the

test pieces to the tests.

  The anchoring of the abrasive grain (corundum) in the hardened phenol-formaldehyde resin is estimated by touching the surface and is evaluated according to the following scale: A = can be moved with the finger B = is firmly fixed and can no longer be moved with the finger. The degree of hardening of the binder is measured on a binder film without corundum, by the method of Knoop (ASTM

  D 1474) The results are given in Table 1.

TABLE 1

  Irradiation time Hardness Anchorage of the grain Example Formula of hardening catalyst ini minutes ASTM D 1474 abrasive

0 O A

37 B

A 'OO (H 2 310 34 B

  ## EQU1 ## 34 BB, <NO 502 - * \ 12 H 25 (n) 10 34 B * e-* me 15 34 B ** \ Il O *% ACH -eC HOSO \ * - CH 5 34 B

3 3 C $ -S-1

MeCH (CH, had 032 B

3 2 1535 B

D 1 <CS - <, \ ,, C S \ -H 53

  3/10 2/1 2 cm 10 10 32 32 clo "21 15 37 B Co Ln I oe TABLE 1 (continued) Example Formula of hardening catalyst Irradiation time Hardness Anchoring grain _____________________________________tion in minutes AST 1 ID 1474 abrasive o on OAEV -CC-EOSO C a (5 n) 3

2 2 \ * / 122 10 35 B

CH 3 15 30 B

O OH

F 5 34 B

* * I * = 10 d 34 B

CHO 57 \ *, 15 I 30 B

I 5 * A

G None * A *

  Not measurable (still soft and sticky).

1-_ r%) Ln W O.- Co CD _j

  The results show that the catalysts whose application

  cation is the subject of the invention do not cause hardening

  binder during the drying step (the non-irradiated coatings are still soft and sticky, the corundum is not anchored firmly) It is only under the effect of radiation exposure that the catalysts are break down into generating

  active sulphonic acids, which allow a hardening

  binder quickly at low temperature.

  at the same time is reduced by 20 minutes.

  at 90 ° C the binder became sufficiently hard while the corresponding test piece without catalyst is still soft and

  after the same hardening time.

  sive is already well anchored after a 5-minute irradiation

  utes; on the other hand she can still move freely in

  specimens that have not been exposed to radiation.

  EXAMPLE 2 Study of the Curing of the Finishing Binder The phenol-formaldehyde resin MS 7215 which has been described in Example 1 is mixed with 30% by weight (relative to the solids content of the phenolic resin) of an A solution. % by weight of catalyst in methyl pentyl ketone, then chalk-filled, the ratio of the resin (100% solids) to chalk being 2: 1.

  obtained on an aluminum sheet by operating as described in the ex-

  To remove the water, the coated aluminum sheet is kept in an oven at 90 ° C for 35 minutes, then the sheet is irradiated for 5, 10 or 15 minutes under Philips luminescent tubes.

  TLK (R) 40/09 at a distance of 15 cm After hardening

  these specimens at 90 ° C for 20 minutes,

  undermines their degree of hardening by the Knoop method (ASTM

D 1474).

  The results are shown in Table 2.

TABLE 2

  Irradiation time Dureti Catalyst formula Catalyst formula in minutes ASTM D 1474

, _ ,,,

0 'u

_, O OH _

\ I I - i / 5 14

  / -C-C-CH 2 OSO 2 - * \ - / N C 12 H 25 14

\ = 10 14

CH 3

17

  , X The measurement is not possible, the test specimen is sticky and soft. The results show that the specimens exposed to

  already have a sufficient hardness after a time of ir-

  5 minute radiation and a curing time at 90 C of 20 minutes On the other hand, the unirradiated test specimen is still soft.

  and sticky after 20 minutes of curing.

Example 3

  MS 7216 aqueous phenol-formaldehyde resin (Ciba Geigy product, dry matter content: 79% by weight, aqueous solution, H 4.5, viscosity: 2.5 to 3.0 Pa S at -5 ° C; molar ratio of phenol to formaldehyde = 1: 1.8) is mixed 30% by weight (relative to the solids content of the resin

  phenol-formaldehyde) of a 10% by weight solution of a cat-

  lyser in methyl-pentyl-ketone By operating as described in Example 1 the solution thus obtained is applied to an aluminum sheet, the latter is coated with corundum, it is stored in an air-circulating oven at 90 ° C. for 35 minutes, then irradiated for 5, 10 and 15 minutes under luminescent tubes After having then carried out a 90 ° C. hardening for 20 minutes, the test pieces are subjected to the tests which have been described in Example 1 The results are gathered in

Table 3.

TABLE 3

  , Catalyst formula Irradiation time Hardness Anchorage in minutes ASTM D 1474 Abrasive grain

'_ I

0 OH _

? II \ O

-C-C- '-

t \ 5 31 B

CH 2-052-S / CH 3 10 35 B

2 B_

29 B

  X The measurement is not possible, the test specimen is sticky and soft For the meaning of the letters A and B, refer to

  comment that was given above in example 1.

Claims (10)

  1 Process for curing abrasive compositions containing   acid-curable binder and, as a catalyst for   hardening, an organic sulphonic acid releasable under the   of light, characterized in that the compositions   abrasives, after being dried, are irradiated and   cies. Process according to Claim 1, characterized in that the curing is carried out at temperatures comprised between 60 and 100 C.   Process according to claim 1, characterized in that   that the irradiation is carried out by ultraviolet radiation.   Process according to claim 1, characterized in that   as a hardening catalyst, an organic compound   which corresponds to one of the formulas (I) and (II), and R-C-f-CHO 502 4 2 L -R 3 i R 7 n (I) (I)   in which: n represents the number 1 or the number 2, R 1 represents an unsubstituted phenyl or naphthyl radical   or carrying, for example, 1, 2 or 3 radicals taken in   seems constituted by -Cl, -Br, -CN, -NO 2, the alkyls in   Cl-C 12, C 1 -C 4 alkoxy, phenoxy radicals, toluene   loxy, phenylthio and tolylthio, C 1 -C 8 alkylthio,   -SCH 2 CH 2 OH, C 1 -C 4 alkylsulfonyls, ph 6 nylsulfo   alkyl, C 2 -C 4 alkoxycarbonyls, C 1 -C 4 alkylamino, C 2 -C 4 dialkylamino, phenyl-COH-, C 1 -C 4 alkyl -CONH alkyl and the benzoyl radical, R 1 may also represent a radical   anthryl, phenanthryl, thienyl, pyridyl, furyl, indole,   lyl or tetrahydronaphthyl, R 2 and R 3 each independently represent hydrogen, unsubstituted C -C 8 alkyl or, for example, an -OH, -Cl, C 1-4 alkoxy radical; C 4, - CN,   C 2 -C 5 alkoxycarbonyl, phenyl, chlorophenyl, alkyl-   C 7 -C 10 phenyl or C 7 -C 10 alkoxyphenyl, or a benzoyl and furthermore R 3 may represent an unsubstituted phenyl or a carrier, for example a -C 1 -C 1 alkyl or C 1 -C 4 alkyl radical. , C 1 -C 4 alkylthio, C 1 -C 4 alkoxycarbonyl, phenyl-NHCO- or -CONH 2, or R 2 and R 3 together with the carbon to which they are attached a C 4 -C 6 cycloalkyl ring, R 4 represents: when N is 1, a C 1 -C 18 alkyl, an unsubstituted phenyl or a carrier, for example a halogen, a C 1 -C 2 alkyl, C 1 -C 4 alkoxy, radical   C1-C4 alkylcarbonylamino, of a radical   n-carbonylamino, a -NO 2 or benzoyl, a naphthalene   unsubstituted tyl or carrier for example a halogen,   of a C 1 -C 12 alkyl or a C 1 -C 4 alkoxy, a cycloalkyl   C 5 -C 6 alkyl, C 7 -C 9 aralkyl, campheryl, -CF 3, -CC 13, -F or -NH 2 and when N is 2, a - (CH 2) m radical in where m is a number from 2 to 8, or an unsubstituted phenylene or naphthylene radical or bearing for example a C 1 -C 12 alkyl; R 5 represents an unsubstituted phenyl or naphthyl radical or bearing 1, 2 or 3 radicals taken; in the set together   by -C 1, -Br, C 1 -C 12 alkyls, phenyl, alcohols,   C 1 -C 4 xy, phenoxy, benzyloxy, C 1 -C 8 alkylthio, phenylthio, -SCH 2 CH 2 OH, alkylcarbonylamino C 1 -C 4 alkyl, benzoylamino, dimethylamino and the like. benzoyl, or R 5 is anthryl or phenanthryl, R 6 is hydrogen, -OH, C 1 -C 4 alkoxy, -O Si (CH 3) 3 -OCOCH 3 or C 1 -C alkyl 8 unsubstituted or ur phenyl carrier, R 7 is hydrogen, unsubstituted C 1 -C 8 alkyl   or carrier of a phenyl, -CN, benzoyl, alkylcarbonyl   C 1 -C 4 alkyl, C 2 -C 5 alkoxycarbonyl or phenyl, and R 8 represents hydrogen, unsubstituted C 1 -C 8 alkyl or a radical -OH, -C 1 or phenyl, unsubstituted phenyl or bearing a radical -OH, -Cl, alkyl   C 1 -C 4 or C 1 -C 4 alkoxy, C 2 -C 6 alkenyl, phenyl-   C 8 or C 9 alkenyl, furyl, thienyl, -CC 13, or saturated or unsaturated C 5 or C 6 cycloalkyl, or R 7 forms with R 5, with R 6 or with R 8 and with skeleton   carbon to which they are attached, a pentagonal or hexagonal   gonal which contains from 1 to 5 of the following groups: -CH 2-,   -CH (CH 3) -, -C (CH 3) 2-, -O-, -S-, -SO-, -502-, -CO-,   -N (CO-C 1 -C 4 alkyl) and -N (COC 6 H).   5. Process according to claim 4, characterized in that, in the formulas (I) and (II): n is equal to 1, R 1 represents an unsubstituted phenyl or carrying a chlorine or a methyl, methoxy, methylthio or phenylthio radical; , -SCH 2 CH 2 OH or benzoyl, R 2 represents hydrogen or C 1 -C 4 alkyl, R 3 represents hydrogen or C 1 -C 4 alkyl, or R 2 and R 3 together form and with the carbon atom to which they are attached a cyclohexane ring, R 4 represents a C 1 -C 18 alkyl, an unsubstituted phenyl or naphthyl radical carrying a C 1 -C 12 alkyl, or a campheryl, R 5 represents an unsubstituted phenyl or bearing a chlorine, a C 1 -C 4 alkyl, a C 1 -C 4 alkoxy, a -SCH 3 radical or a phenyl , R 6 is -OH or C 1 -C 4 alkyl, R 7 is C 1 -C 4 alkyl or phenyl, and R 8 is -H, C 1 -C 4 alkyl, furyl or -CC 13, or R 7 and R 8 together and with the carbon atoms who   carry them a core of cyclohexane.   Process according to Claim 4, characterized in that, in formulas (I) and (II), N is 1, R 1 and R 5   each represents a phenyl, p-tolyl or p-methylthio radical.   phenyl, R 2 represents hydrogen, R 3 represents a radical   methyl, isopropyl, n-decyl or benzyl, R 4 represents a radical   phenyl, p-tolyl or p-n-dodecylphenyl, R 6 is -OH,   R 7 represents -CH 3 or a phenyl radical, and R 8 represents -H.   Process according to claim 1, characterized in that the acid-curable binder is a phenoplast or a   aminoplast or mixtures thereof.   Process according to claim 7, characterized in that the acid curable binder is a phenol-formaldehyde resin. Process according to claim 7, characterized in that   that the acid curable binder is a resol.   Process according to claim 1, characterized in that the acid-curable binder contains from 0.1 to 10% by   the weight of the curing catalyst, relative to the binder de- provided with solvent.   Process according to claim 1, characterized in that that the binder is the basic binder.   Process according to claim 1, characterized in that   that the binder is the finishing binder.   The process according to claim 1 for the manufacture   sanding abrasives on planiform supports.