DD202255A5 - GRINDING FABRIC - Google Patents

Abstract

A coated abrasive of improved resistance to <<loading>> comprising a flexible backing, a plurality of abrasive grit particles dispersed over the area of at least one surface of said backing, and at least one layer ot adhesive bond material adhering said abrasive grit particles to each other and to said backing, characterized by the fact that the outermost layer of said adhesive bond material comprises: (a) animal glue, or a cured amino resin, or a mixture thereof in an amount of at least 40% by weight of the total adhesive bond material, exclusive of any filler; and (b) at least 0.74 grams per square meter of an additive which is (1) a mono-, di-, and tri-organyl ester of orthophosphoric acid, (2) a salt of a mono-, di-, and tri.organyl ester of orthophosphoric acid with an amine, (3) a tetraorganylammonium salt, or (4) a soluble mixture thereof. Best results are obtained with a sizer adhesive of amino resin containing phosphate esters or their amine salts as additive.

Description

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Abrasive fabrics Field of application of the invention:

The invention relates to abrasive fabrics which consist of flexible supports, to which adhere on at least one side numerous abrasive sand grains. Abrasive fabrics are mainly used for forging, sizing or altering the surface finish of other material articles generally known as workpieces. Small particles of material removed from the workpiece and / or protective layer by the abrasive fabrics during processing are commonly referred to as "abrasive slurry." In many. Unfortunately, the abrasive slurry shows the tendency to remain completely or partially adhered to the surface of the abrasive cloth and eventually to smudge and clog its abrasive surfaces, rendering it unusable for further use. Above all, the invention relates to abrasive fabrics which have special resistance to such defects due to smearing.

Characterization of the known technical solutions; A generally accepted engineering practice for the manufacture of abrasive fabrics that are resistant to smearing in the abrading of paints, primers, wood seal coatings, and various other surface treatment agents used on workpieces is essentially that disclosed in U.S. Patent No. 2,768. 886 described. This patent teaches the production of abrasive fabrics having on the abrasive side a final surface coating of unfused metal soaps, preferably applied from a dispersion of such a soap in a volatile liquid. The application of this metallic soap is done in a separate coating step in addition to the usual bonding and sizing coating steps commonly employed to achieve adhesion of the abrasive grains to the substrate. In some cases, it is quite possible to

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use of a glue adhesive. The need for an additional coating operation, compared to most other abrasive fabrics, means labor and material costs that, of course, are best avoided.

Since the publication of the above-referenced patent, various other patents have concerned other types of "third" coatings (ie, coatings in addition to the two normal adhesive and size coatings) to achieve anti-smear abrasive fabrics, examples include polyvinyl acetate according to CA-PS No. 931,767, polytetrafluoroethene and mixtures thereof according to US Pat. No. 3,044-2,508 cmd mixtures of thermosetting resins, elastomers and metal soaps according to US Pat. No. 3,619,150.

U.S. Patent 3,143,673 teaches the use of oxygenated compounds, either as a third layer or in the conventional size base layer of a slip fabric, in conjunction with an exceptionally high binder adhesive to granule ratio as an effective measure to increase the resistance of abrasive fabrics to smearing the surface treatment of leather and similar materials. U.S. Patent 3,089,763 relates to the use of polyoxyalkylene linkages in the size layer of abrasive fabrics, and one of the stated objects is U.S. Patent No. 3,089,763 Reduction of smearing. However, the findings of this US patent are limited to primer base compositions in which the major ingredient is an amine catalyzed phenolic resin.

Object of the invention:

It is a primary object of the invention to provide abrasive fabrics which are as resistant to smearing as products having third metal soap coatings but which do not require a true third coating. Other goals

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will be clear from the following description »

Explanation of the essence of the invention

It has been found that resistance to terschelling may be imparted to conventional scissors webs by size primer coatings containing glues or amine resins by blending into the size small amounts of specific chemical compounds and mixtures as described below. These additives are complete or partial allyl esters of phosphoric acid, amine salts of partial esters of phosphoric acid and quaternary ammonium salts having at least one long alkyl or substituted long alkyl group. Typical examples would be the triethanolamine salt of mono- or didecyl phosphate or suearamidopropyl - ^ - hydroxyethyl ammonium nitrate. In the investigations leading to this invention, conventional abrasive cloth carriers, adhesives and abrasive grains have been used. The invention is applicable to all those products which "contain such constituents including the full range of abrasive sand sizes of normal engineering practice, including at least those with the numerical size designation of 12 to 600 'as defined in the AlSI Standard B74-. 1977. As known to those skilled in the art, suitable ingredients include, but are not limited to, papers having a weight between 50 and 300 grams per square meter (g / m), appropriately made (finished) fabric of various types, and vulcanized fibers As the abrasive grains, synthetic molten alumina, silicon carbide, garnet, zirconia dioxyd alumina, emery, flint stone or other materials may be used, and the adhesives (maker adhesives) may be film-forming starches, animal hide glue, amino resins, etc.

The tested additives, which showed a detectable effect for the smearing reduction when used in the glue base layer, are summarized in Table 1. These additives had the greatest effect, though

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it was used with amino resins such as urea-formaldehyde or melamine-formaldehyde. Such amino resins could be mixed to equal parts by weight with phenol-formaldehyde resins, one amino resin could be blended with another, and each of the resins or blends could be filled with finely divided pesticides such as calcium sulfate, walnut shell meal, or any of the other known fillers used to make abrasive fabrics become. Suitable types of naturally derived size may also be used as a base coat, but the quality of the product with size primers will normally not be as good as with resin priming, even in the absence of the additives described herein.

In connection with the additives according to the invention, other well-known substances such as pigments or dyes, diluents for reducing the viscosity, antifoam agents, etc. may be used as required or if desired. Bs no adverse interactions between such substances and the additives of the invention were observed. A particularly important class of conventional ingredients in amino resin adhesive formulations are the oxyamine useful for hair tear resistance, as described in Duke US Pat. No. 2,983,593, the entire specification of which is incorporated herein by reference. The use of Duke adhesive compositions in conjunction with the inventive additives is preferred.

Table 1 '

Adjuncts that improve the smear resistance of amino resin and xeneminer adhesives for abrasive fabrics' ''

trademark

adhesive

supplier

Chemise he marking "*"

Zelec ΈΕ

Zelec W. Monafax L-10

Group A I.I. DuPont

EGG. DuPont Mona Industries

Monafax 786 Smphos PS-400

Monafax 785 Monafax H-15 Cyastat SN Cyastat SP

12-1373

Mona Industries Group B Witco Chemical

Mona Industries Mona Industries American Cyanamid American Cyanamid

Calgon Corporation

Neutralized fatty alcohol phosphate j

Fatty alcohol phosphate Mixture of mono- and diphosphate esters derived from iithylene oxide-based surfactants The same as Monafax L-10

Complex of organic phosphates

The same as Monafax L-10 The same as Monafax L-10 Stearamidopropyl- hydroxyethyldimethylammonium salts Fitrat for SlT, dihydrogenphosphate for SB mixture of dimethylallylammonium chloride and methylolacrylamide

According to specification of the supplier

It should be noted that some of the additives listed in Table I. acidic and thus are _able} to catalyze the curing of amino resins. Such a practice would have to include the Eisiko of shortened potlife of the amino resin compared to the catalysts mentioned by Duke. Thus, in the practice of the invention, it is usually better to use the admixture, if it is acidic, with a suitable

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Neutralize ammonia or ammonium hydroxide before adding it to the amino resin adhesive formulation. When this is done, the resinous adhesive can be cured with the additive of the invention with the same time and temperature schedule as is applicable to the same resin without additives. It recommends.sioh one of Doke mentioned Oxyamine for neutralization of the invention. Additive to use, if necessary.

For example, Zelec.HS, which is as supplied neutral, could be added directly to a conventional composition as in Example III of the Duke PS after all other ingredients listed have been mixed together. On the other hand, Zelec SK, which is acidic, should first be best neutralized in a separate container with 2-amino-2-methylpropanol and the neutralized mixture then added to such conventional formulation after the addition of all other ingredients. All preceding and subsequent steps in the production of abrasive fabric may be carried out in a conventional manner.

It has been determined that the minimum amount of additive is sufficient to achieve a useful smear resistance. that is the one that corresponds to a mass of 0.74 grams per square meter. ¹ Above 10% by volume of the total glue adhesive is generally not recommended because it may reduce the heat resistance of the glue adhesive which may result in the risk of reducing the abrasive efficiency. Generally, a useful range is between 0.74 and 13.3 grams of additive per square meter, and the preferred range is between 1.2 and 3> 5 grams per square meter. This can be achieved in most cases by using the additive in an amount of 3 to 5 mass of the resin or glue used.

The additives listed in Table 1, all blended easily with amino resin or glue suspensions, give liquid mixtures which were uniform as far as it could be visually assessed, although in some cases a cloudy or milky appearance of the mixture was noted. which suggests a dispersion rather than a true solution. During processing, there was no direct evidence of any tendency of the additive-containing adhesive mixture to develop inhomogeneities under normal conditions of coating, drying or curing. Due to the chemical nature of the preferred additives, the ionic bonds and at least one long organic chain in contained any molecule, one could expect gedoch that such additives the surface tension of the. most liquid adhesives in which they are mixed would effectively reduce. When such surface tension reduction actually occurs, the well-known Gibbs equation for such surfactant varieties predicts that the surfactant components spontaneously disperse at equilibrium to thereby form a surface layer enriched with the surfactant component. This spontaneous concentration of additive in the surface layer may explain why the minimum amount of additive required to achieve a detectable increase in smear resistance is more related to the area of the coated abrasive product than to the volume of the adhesive. The levels of the size coat level for products coated with the primer-containing size primers according to the invention should generally correspond to those of conventional products which are not to receive an additional third coating. In some cases, suitable levels can be readily determined by those skilled in the art of making abrasive fabrics.

Table 2 shows examples of specific products prepared according to the method of the invention.

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The four additives listed in Table 1 as Group A were generally prepared to be equivalent in their ability to produce resistance to comminution when added to amino resin size primers. Products having these additives in the prime base coating have been tested in the sanding of a wide variety of paints, metallic primers, enamels, enamels, varnishes, etc., and have generally been found to have a longer shelf life than previous commercial ones for grinding such Had produced standard products. (Such commercial products usually have a third layer containing mainly zinc stearate or another similar metallic soap). The other additives listed in Table 1 are listed in groups of decreasing effectiveness in producing smear resistance in the glue adhesives.

In the present specification and appended claims, the term "organyl" as used herein includes any chemical group that can be formed by the resolution of a valence bond in an organic compound. Thus, organyl includes the groups normally referred to as alkyl, alkenyl, alkynyl, aryl, such as phenyl, and combinations of and substitutions with the other simple groups, as well as a wide variety of other "eirr." "long organyl" refers to an organyl group having at least eight linearly linked carbon atoms. The linear bond may include double or triple as well as simple carbon-carbon bonds. The term "layer" in the description of a body of adhesive material should be understood to include any substantially continuous mass of material of substantially uniform composition, with a protruding surface covering substantially the entire surface of an abrasive layer backing. Due to the presence of abrasive sand grains in an abrasive cloth, it is believed that the layers of the adhesive used for the construction have very irregular outer surfaces as opposed to

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These smooth parallel surfaces, which are normally assumed at the working layer during normal use. For example, the adhesive and prime base layers mentioned above in the brief description of the normal manufacturing process for an abrasive fabric would represent layers in the final product, as would any single layer of metal soap applied to provide anti-icing resistance. It should be further understood that the substantial uniformity of the composition of an adhesive layer should also include any natural accumulation of a surfactant incorporated into the adhesive layer when applied in liquid form. The actual continuity of an adhesive is also not affected by the presence of normal bending cracks in an abrasive cloth.

Table 2

Specific examples Type g / m ² For Yerschmierungsbeständigkeit of size g / m ² Leimklebemitte1 Main additive Surname 1.2 3.3 Abrasive wheels; 360 4Λ total   Zelec HB 1 ₅ 2 Layer adhesive • BFl 15 320 44 g / m ² SI Mo no fay 1-10 2.5 carrier M1 15 Schleifkör 220 77 30 SI Zelec SS 1.2 M1 19 by 220 40 30 Si Zelec IK 2.5 B1 12 12 Type 180 98 62 SI Monafas 785 1.2 B1 M1 22 G1 180 53 30 SI Monaf as 786 5.3 B1 - SfI 22 G2 80. 129 62 S2 Gyastät SN Bmphos PS-400 3.1 B1 13 118 G3 120 138 30 S2 E-1373 B2 M1 26 G4 220 115 133 S3 B1 151 56 G2 77 SI B3 G5 81 B1 G6 B4 G1 G1

following the list in Table 1

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Legend;

g / m means grams of the dried material, given per square meter of abrasive cloth

Layer support? B1 is 68 g / m ² kraft paper (grade 28729 from Kimberly-Clark); B2 is slightly heavier kraft paper (grade 54729, by Kimberly-Clark); B3 is 13O pound (220 g / m) N-cylinder paper from James River; B4 is twill cotton 2O7CC from Horton Co. _s .

Adhesives: M1 is 92 millipois animal glue; H2 is Ucar I3I latex from Union Carbide; M3 is urea-formaldehyde resin GPX-J1-6 from Georgia-Pacific.

Abrasive granules: G1 is SWPL type aluminum oxide from Treibacher USA, Inc .; G2 is aluminum oxide type EHPL from Treibacher; G3 is Alundun Type 57 from Lorton Co .; G4 is Garnet by Barton Mines; G5 is silicon carbide from Norton Co .; G6 is a mixture of Alundun Type 57 and Alundun HZ from Forton Co. in a volume ratio of 6: 4.

Sizing agent : Si is urea-formaldehyde resin, type Beetle 7238-20 from American Cyanamid; S2 is urea-formaldehyde resin, type GPX-J1-6 from Georgia-Pacific; S3 is a blend of Beetle 7238-20 and 2535 phenolic resin from Varcum Chemical Co, in equal parts by weight.

Claims (6)

\ ί Ib ι Erfindungsatispruch: An abrasive fabric product comprising a flexible backing, numerous abrasive sand grains distributed over the surface of at least one surface of the backing, and at least one layer of adhesive bonding material bonding the abrasive sand grains together and the backing, characterized in that the outer layer of the adhesive tie comprises: (a) animal glue or a hardened araoin resin or a mixture thereof in an amount of at least 40% by weight of the total adhesive bonding material, excluding any filler! and .;.; "Cb") at least 0,74 grams of an admixture per square meter of which: (1) a mono-, M- or triorganyl ester of orthophosphoric acid, (2) a salt of a mono-, di- or triorganyl ester of orthophosphoric acid with a 1min, (3) a letraorganylammonium salt, or (4) a soluble mixture thereof. 2. Abrasive fabric according to item 1, characterized in that the additive in the outermost adhesive layer has at least one long organyl group per molecule. 3. Abrasive fabric according to item 1 or 2, characterized in that the outermost layer of the adhesive bonding material contains hardened urea-formaldehyde resin in an amount of at least 40% by weight of the total adhesive bonding layer, excluding any filler. 4. Abrasive fabric according to item 3, characterized in that, after curing, the outermost layer of the adhesive bonding material also contains the residue of a latent curing system consisting essentially of: (1) an ammonium salt of a. Acid with a dissociation -4 constants of at least 10; and _ ₁₂ _ Ml / £ b / (2) an amino compound having at least one primary amino group attached to a tertiary carbon atom and a hydroxyl or itheroxy atom bonded to a second carbon atom adjacent to the tertiary carbon atom, said amino compound being in a position to increase the pH of the total adhesive composition from 6 to 9 v °? sufficient amount of curing of the adhesive is present. 5. Abrasive fabric according to item 4, characterized in that the amino compound is 2-methyl-2-aminopropanol, 2-amino-2-methyl-1,3-propanediol, 5-amino-5-methyl-1 , 3-dioxane, iris (hydroxy! Qethyl) aminoinethane, or 2-amino-2-ethyl-1,3-propanediol. 6. Abrasive fabric according to one of the items 1 to 5> characterized in that at least two adhesive layers are present - the layer closest to the outermost layer contains at least 40% by volume of animal glue or dried latex.