WO2009030850A2

WO2009030850A2 - Method for making a substrate for an applied abrasive product and substrate thus obtained

Info

Publication number: WO2009030850A2
Application number: PCT/FR2008/051424
Authority: WO
Inventors: Thierry Mayade
Original assignee: Arjowiggins Licensing
Priority date: 2007-07-31
Filing date: 2008-07-29
Publication date: 2009-03-12
Also published as: FR2919513A1; WO2009030850A3; FR2919513B1

Abstract

The invention relates to a method for making a substrate for an applied abrasive product that comprises applying a treatment for making at least one area of at least one face of the substrate water-repellent for an attachment layer of abrasive grains.

Description

Process for manufacturing a support for an abrasive product applied and a support obtained

The field of the present invention is that of abrasive products applied as well as that of the manufacture of abrasive products applied by transformation of their support. The present invention relates to a method of manufacturing an abrasive product applied whose abrasive grains are distributed in a pattern.

For the purposes of the invention, the term "abrasive applied" means an abrasive product comprising a support on one side of which abrasive grains are subject.

According to one embodiment of an applied abrasive, is deposited on one side of the support (faceplate) a sizing layer and abrasive grains coated with an overcoat layer.

In particular, the overcoat layer may optionally be covered with a supercollage layer containing in particular waxes, stearate, in particular zinc, or functional charges. In particular, their purpose is to limit fouling, improve lubrication or limit heating of the abrasive applied during its use.

In the same way, other layers fulfilling a special function can in particular be placed on or between the previous layers or on the back of the support. In particular, the special function may consist of antistatic treatment. The support may be a paper, a nonwoven, a polymer film, a primed fabric or a vulcanized fiber-based support, these supports being able to be combined in particular so as to obtain better characteristics of use.

In the case of paper, the paper is made from cellulose fibers, possibly mixed with synthetic fibers, and it generally comprises a sizing agent and possibly other additives conventionally used in stationery such as as wet strength agents. In addition, the support may comprise antistatic agents or other products deposited in aqueous medium by coating or impregnation, for example a dispersion polymer synthetic rubber type giving it flexibility. The so-called "transformation" step makes it possible to obtain an abrasive product applied from the support described above. The transformer generally performs this step according to the method explained below. The sizing layer is deposited on the support by a suitable coating means, for example roller coating. This sizing layer, commonly known to those skilled in the art as "make coat" is a composition that can be carried out in an aqueous medium or in a solvent medium and comprising a curable adhesive which can be a natural adhesive such as starch, gelatin or a synthetic resin such as a phenolic resin, urea formaldehyde, melamine formaldehyde, polyurethane, epoxy, alkyd, acrylic, polyvinyl alcohol or a mixture of the above-mentioned resins, adhesive to which is added the most often a filler, in particular a mineral filler such as calcium carbonate, calcium sulphate or cryolite. It may further include other additives such as plasticizers, dyes, surfactants, especially wetting agents and defoamers, or antistatic products.

Abrasive grains are then applied to the undried sizing layer. In particular, they can be deposited by electrostatic deposition or by gravity. The abrasive grains may especially be chosen from aluminum oxide, silicon carbide, garnet, emery, boron nitride, as described in patent application EP 0 352 811, or alternatively oxide of zirconium. In particular, the abrasive grains can be in the form of aggregates composed of agglomerated grains, these aggregates having a longer life and providing greater consistency in the quality of abrasion.

The person skilled in the art chooses the nature of the abrasive grains according to the type of abrasion desired and the part to be abraded.

Moreover, the particle size of the abrasive grains may in particular be chosen according to the surface to be abraded and the desired level of polishing. Usually in Europe, abrasive grains are graded according to a standard set by F. P. A. (Federation of European Producers of Abrasives); the grade for an abrasive product applied is a reference starting with the letter P followed by a number indicating the "grain number", the higher the number, the more abrasive grains are fine. Other standards may be used in other countries, particularly

United States of America (ANSI standard) or Japan (JIS standard). In particular, several types of abrasive grains can be deposited in one or more layers.

Alternatively, the sizing layer and the abrasive grains may be deposited together if previously mixed. The thus coated support undergoes a first drying to harden the curable adhesive.

The first drying is usually done in a festoon oven or a linear oven. The temperatures and drying times are chosen by those skilled in the art according to the nature of the sizing layer. Most often this treatment is carried out according to gradients of temperature and humidity along the furnace; for example, the sizing layer can be dried with the abrasive grains for 15 to 45 minutes at 65 to 115 ^° C. In particular, in the case of the use of solvent resins, starch or gelatin, significantly shorter drying times can be achieved.

The next step consists in depositing a layer of over-coating, or re-gluing, commonly referred to by the skilled person as "size coat", which comprises the same type of compounds as those mentioned for the sizing layer. . The viscosity of the overcoat layer is generally lower than that of the sizing layer so as to favor its infiltration between the abrasive grains without completely covering them but there are certain exceptions, for example when using a diaper sizing agent comprising a phenolic resin and an overcoating layer comprising an epoxy resin. The overcoat layer thus makes it possible to reinforce the fixing of the abrasive grains.

The product thus obtained is then dried again and the resin of the overcoat layer is partially or fully cured depending on the nature of the curable adhesive. As before, the temperatures and drying times are adapted to the nature of the overcoat layer; for example, the product can be dried for 20 to 140 minutes, between 65 and 120 ^° C. in a festoon oven.

In general, after this second passage in the oven, the product obtained is put into coils called in terms of trade "jumbo coils". The reels may then be subjected to an additional post-crosslinking step depending on the nature of the curable adhesives used in the sizing and overcoating layers. Indeed, in the case of thermosetting resins, for example such as the phenolic resins, the coils are treated in such a way that the sizing and overcoating layers crosslink after an exposure of several hours, generally between 4 and 72 hours, at a temperature of about 90 to 150 ^° C. In in some special cases, the exposure time can reach a week. For curable adhesives that do not require a postcrosslinking or firing step, such as urea formalin, epoxy resins or gelatin, the drying and curing are completed after the second pass through the oven.

The coil thus obtained is then cooled, for example up to 40 ^° C. After this heat treatment pushed, the back of the support must be repacked. This operation is performed by uncoiling the coil to wet with water optionally containing additives or with water vapor, and then winding again as a coil. The reel is then left in the state for a period of time, generally ranging from a few hours to a few days, in order to rewet and reach equilibrium. In addition, the abrasive product may in particular be subjected to a so-called

"Fiexage" for softening the abrasive applied in one or more directions. Said fixing step may in particular be anterior, concomitant or subsequent to the repacking step.

In a conventional manner, the fxxage step is carried out by unrolling the "jumbo coil", passing the sheet thus unwound beneath or on a bar at certain angles and then winding the sheet into a reel.

Another way of proceeding is to unwind the "jumbo coil" through a nip between a large diameter cylinder and a cylindrical rod surrounded by a thread to achieve fxxage in several directions. The reels are then optionally cut into the desired format, especially in the form of discs, sheets, triangles or narrow strips, in particular used for sanding songs, or wide, especially used for sanding panels. In particular, the strips may be intended to be assembled in an endless band. There is a need for coated abrasive products whose abrasive grains are patterned, i.e. applied abrasive products having abrasive grain free areas which form abrasive grains with the areas provided with abrasive grains. motifs. In particular, this demand corresponds to both technical and commercial needs.

The use of applied abrasive products causes the formation of dust which are in particular particles of the abrasive material generated by the abrasion operation. These dusts accumulate between the material to be abraded and the applied abrasive product used thereby decreasing the effectiveness of the abrasion operation. The use of applied abrasive products whose abrasive grains are patterned is one of the commonly used means for facilitating the evacuation of dust.

Another advantage of the applied abrasive products whose abrasive grains are distributed in patterns is to have a lower heating during their use, compared to coated abrasive products whose grains are distributed homogeneously. The patterns free from resin and abrasive grains indeed allow ventilation of the system abrasive products applied / support to be treated which thus limits warming. As a note, warming can affect the effectiveness of the abrasion operation. When sanding wood material for example, warming causes softening of wood resins that become sticky and reduce the action of abrasive grains. The heating of the abrasive products applied also induces their loss of moisture and their embrittlement.

In addition, manufacturers of coated abrasive products are looking to produce products whose abrasive grains are distributed in patterns representing for example their brand. Such products would indeed be an element of differentiation for them compared to their competitors.

Currently, coated abrasive products whose abrasive grains are distributed in patterns are made with specific rolls etched for the removal of the resin. In particular, the specific rolls are metal cylinders engraved in relief or in relief in patterns. The resin is transported in the hollows of the roll then it is deposited on the support in the patterns drawn by the engraving of the roll. The abrasive grains then deposited will therefore be fixed only on the areas coated with resin. According to another method described in application WO 93/13912, the support is first embossed and then the depressions thus formed are coated with an abrasive formulation composed of abrasive grains dispersed in a precursor binder and an expansion agent. According to a variant of this method described in the application WO 03/057410, the support is first coated with an abrasive formulation composed of abrasive grains and a binder, then embossed so as to make the patterns.

The methods described in the previous paragraphs have the following disadvantages:

- Specific rollers are heavy and bulky equipment, so their engraving represents significant investment,

- The number of reasons is limited by the number of rollers that has the transformer or the rollers are expensive equipment, - Because of the volume of the rollers, handling is difficult and requires long stops of the processing machinery thus reducing the production of processing machines.

Another technology currently used is to use stencils.

In particular, the resin may be uniformly deposited on the support or in a pattern. The abrasive grains are deposited on the support according to the patterns of the stencil placed between the support and the device for depositing the abrasive grains. This technology is described in particular in US Pat. Nos. 5,380,390, 5,980,678 and 5,817,204.

Although it is more flexible than the engraving of rolls, this technology requires several operations during the transformation of the support for abrasive product applied: - place and remove the stencil for a discontinuous or semi-continuous process, or manage the scrolling of the stencil above of the support in the case of a continuous process (for example use of an endless band acting as stencil)

- Recover the abrasive grains not being fixed, because of the stencil, on the resin-coated support. According to the invention, there is provided an applied abrasive holder enabling the transformer to produce coated abrasive products whose abrasive grains are patterned, while retaining conventional equipment and process used to produce coated abrasive products including grits. Abrasives are spread over the entire support. The subject of the invention is thus a process for manufacturing a support for an applied abrasive product in which a treatment consisting in rendering at least one zone of at least one face of the support for an abrasive grain fixing resin.

The term "water-repellent treatment" means any treatment having a repulsive effect on the fixing of any product and, in particular in the context of the present invention, on said resin for fixing abrasive grains.

The water-repellent treatment may in particular be carried out so as to create patterns on at least one face of the support.

By "water-repellent zone for a component" is meant any zone on which the component can not be located or be fixed, this component being in particular a resin for fixing said abrasive grains.

In a particular embodiment of the invention, the water-repellent treatment comprises the application of at least one resin, such as a wax, in particular

Carnauba, montanic, paraffin, polyethylene or polytetrafluoroethylene

(PTFE), such as a silicone resin, in particular of polymetoxysilane, or such as a fluorinated resin.

In addition and according to an advantageous embodiment, the water-repellent treatment can comprise, in addition to the application of said at least one resin, the application of at least one binder, in particular such as a natural or synthetic latex. , in particular a butadiene styrene, an acrylic styrene, a polyvinyl acetate, a copolymer of vinyl acetate and of vinyl chloride or of polyethylene, a polychloroprene, a nitrile butadiene or a polyurethane, or else such as a polyvinyl alcohol, or a resin, in particular an acrylic resin or urea formaldehyde.

In addition, according to the invention, the water-repellent treatment can comprise, in addition to the application of said at least one resin, the application of at least one adjuvant, in particular such as kaolin, talc or sodium carbonate. calcium.

The water-repellent treatment can be implemented by coating by zones, by spraying and using a stencil, or by printing, in particular by gravure, flexography, screen printing or inkjet printing.

According to the means used for the implementation of the water-repellent treatment, the invention may return to move the difficulty of the transformer to the producer of the support located upstream. Indeed, the use of rotogravure requires the engraving of metal rolls. Despite this, the present invention remains advantageous since the support producer manufactures larger tonnages and thus ensures a better return on the investment required to achieve the invention.

In addition, the producer implementing the present invention will have: - either a machine intended for the manufacture of the support, for example a paper machine or a machine for finishing and / or finishing textile materials, and a device for applying said water-repellent treatment placed "off-line", in particular by spraying, coating or printing,

- Or a machine for the manufacture of the support and the application of said water repellent treatment "in line", in particular by spraying, coating or printing.

In the first case, or "offline" case, the producer has greater flexibility than the processor during production since he can choose whether or not to use the "offline" printing device, respectively. to obtain a product according to the invention and an applied abrasive medium whose abrasive grains are distributed homogeneously. The transformer meanwhile is usually forced to use at least two rollers to achieve the two products mentioned above.

In the second case, or "online" case, the producer also has greater flexibility since he can choose whether or not to use the printing element of the machine intended for the manufacture of the support and its printing. respectively to obtain a product according to the invention and an applied abrasive medium whose abrasive grains are distributed homogeneously.

Thus, in all cases, the transformer must either deposit the resin in a pattern, or drop homogeneously over the entire surface of the abrasive product applied. This involves a change in the printing device, whereas the producer of coated abrasive media has the advantage, whether or not to use the water-repellent treatment, which does not imply changes in the printing device but only the realization or not of a step. According to the invention, the water-repellent treatment can be carried out online or offline with respect to a device for manufacturing the support for abrasive products applied. The support for abrasive product applied may be flat. It is particularly a support commonly used in the field of coated abrasive products and in particular a sheet, a film or a canvas.

The coated abrasive carrier may be a sheet of vulcanized, cellulosic, synthetic fibers, particularly such as polyamide and / or mineral fibers, in particular such as glass fibers, plastic film, in particular such as polyester film, or a fabric comprising cotton fibers and / or synthetic fibers, in particular polyester.

In addition, the support for abrasive applied may in particular comprise one or more layers such as those described above. In particular, it may be a mixture of layers such as those described above.

According to the invention, the sheet may comprise adjuvants. These are in particular adjuvants commonly used in the production of coated abrasive media, especially dry strength agents such as starch, polyvinyl acetate or gelatin, and or wet strength agents such as synthetic latex (colloidal dispersion mixture), urea formaldehyde, melamine formaldehyde, polyamine-amide-epichlorohydrin (PAAE), isocyanate or an alkyd resin.

In particular the adjuvants are added by mass in the sheet or by impregnation of the sheet after its formation. In the case of a film, it has a thickness of between 25 and

150 μm.

In the case of a sheet, it has a grammage of between 50 and 1000 g / m ² , preferably between 80 and 600 g / m ² .

In the case of a fabric, it comprises a mass and / or surface treatment based on starch, polyvinyl acetate, gelatin, synthetic latex, urea formaldehyde, melamine formaldehyde, phenol formalin or a mixture of the compounds mentioned above. When the canvas is so treated, we usually talk about canvas

"Primed".

The primed or ennobled fabric has a basis weight of between 150 and 1000 g / m ² .

The invention also relates to an applied abrasive product support obtained by the method described above. The subject of the invention is also a method of manufacturing an applied abrasive product comprising the steps of: depositing on one face a support obtained by the manufacturing process previously described, a sizing layer, - depositing on the layer for sizing the abrasive grains, depositing on the abrasive grains an over-coating layer, optionally depositing on the super-bonding layer a super-bonding layer, possibly disposing on or between the layers one or more layers fulfilling a special function, in particular consisting of antistatic treatment.

The sizing layer and the abrasive grains can be deposited together on the support when they have been mixed beforehand.

The invention will be better understood on reading the description which follows, non-limiting examples of implementation, and the examination of the following figures.

EXAMPLES

Below are examples of composition that can serve as a water-repellent resin, that is to say resin used in the water-repellent treatment of a support, in the implementation of the method according to the invention.

If necessary, the viscosity of the formulas presented below is decreased by adding water.

Example 1

Formula 1 based on paraffin wax: - 60% by weight of an emulsion of paraffin wax Ultralube E340 ^®

Keim-Additec

40% by weight of a styrene butadiene latex DL950 from Dow ^® Example 2

Silicone formula 2: - 50% by weight of Elastolam VS ® from Lamberti (silicone) 50% by weight of a BASF Acronal T290D ^® styrene acrylic styrene (acrylic styrene)

Example 3

Formula 3 based on fluorinated resin: - 30% by weight of an Asahi Guard fluorinated resin AG955 ^® (fluororesin)

70% by weight of a 15% solution of polyvinyl alcohol Mowiol 20-98 ^® from Kuraray

DESCRIPTION OF THE FIGURES

FIG. 1 represents an engraved roll used to deposit the water-repellent treatment according to one of the aspects of the method according to the invention.

Figure 2 shows an abrasive product applied according to the invention.

Figure 3 shows another example of abrasive product applied according to the invention.

According to one aspect of the invention, the method of manufacturing an abrasive product applied may in particular consist in the application of a water-repellent layer, that is to say a layer on which the abrasive grains can not be fixed. , for example according to one of the formulas 1, 2 or 3, on a support using an engraving roll 1 having a multitude of "diamond" -shaped shapes, as represented in FIG. 1.

The engraving roll 1 having a multitude of shapes of the "diamond" type advantageously makes it possible to obtain a multitude of water-repellent zones for the resin for fixing the abrasive grains, thereby making it possible to create a pattern.

Once the support obtained, it proceeds to the manufacture of the abrasive product applied which then consists of applying a sizing layer and the deposition of abrasive grains, including electrostatism.

As a result, an abrasive product 2, as shown in FIG. 2, is obtained on containing zones 3 free of grains, these zones having undergone a water-repellent treatment, and zones 4, on which there are abrasive grains and a resin. these areas have not undergone water-repellent treatment. In Figure 3 is shown a portion of an abrasive belt applied according to the invention. As in FIG. 2, the zones 3 have undergone a water-repellent treatment and are therefore devoid of abrasive grains, whereas the zones 4 have not undergone a water-repellent treatment and therefore comprise abrasive grains as well as a fixing resin.

Of course, the invention is not limited to the embodiments which have just been described.

The expression "having one" shall be understood as being synonymous with "having at least one", unless the opposite is specified.

Claims

A method of manufacturing an applied abrasive product carrier in which a treatment is carried out consisting in rendering at least one zone of at least one surface of the support for an abrasive grain fixing resin water-repellent.

2. The method of claim 1, the treatment being performed so as to create patterns on said at least one side of said support.

3. Method according to any one of the preceding claims, the treatment being applied by zone coating, by spraying, by means of a stencil or by printing, in particular by gravure, flexography, screen printing or inkjet printing.

4. Method according to any one of the preceding claims, the treatment being carried out online or offline with respect to a device for manufacturing said support.

5. Method according to any one of the preceding claims, said support being of planar shape.

6. Process according to any one of the preceding claims, said support being a sheet, in particular a sheet of vulcanized, cellulosic, synthetic fibers, in particular such as polyamide fibers, and / or mineral fibers, in particular such as glass.

7. Method according to any one of claims 1 to 5, said support being a film, in particular a plastic film, in particular a polyester film.

8. A method according to any one of claims 1 to 5, said support being a web, in particular a web comprising cotton fibers and / or synthetic fibers, in particular polyester.

9. Process according to any one of the preceding claims, said support comprising one or more layers, alone or as a mixture, mentioned in any one of Claims 6 to 8.

10. The method of claim 6, said sheet comprising adjuvants.

11. The method of claim 7, said film having a thickness between 25 and 150 microns.

12. The method of claim 6, said sheet having a basis weight between 50 and 1000 g / m, preferably between 80 and 600 g / m.

13. A method according to claim 8, said fabric comprising a mass and / or surface treatment based on starch, polyvinyl acetate, gelatin, synthetic latex, ureformol, melamineformol, phenol formalin, alone or in mixture.

14. The method of claim 8, said web having a basis weight between 150 and 1000 g / m ² .

15. Support for applied abrasive product obtained by a manufacturing method according to any one of the preceding claims.

16. A method of manufacturing an applied abrasive product comprising the steps of: depositing on one side of a support obtained by the manufacturing method according to any one of claims 1 to 14, a sizing layer, deposit on said abrasive grain sizing layer, - depositing on said abrasive grains an overcoat layer, optionally, depositing on said overcoat layer a supercollage layer, optionally, disposed on or between said layers one or more layers performing a special function, including consisting of antistatic treatment.

17. Method according to the preceding claim, said sizing layer and said abrasive grains being deposited together on said support when they were mixed beforehand.