JP3290404B2 - Method of manufacturing resin filament containing core for brush - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin filament containing an abrasive used for a brush.

[0002]

2. Description of the Related Art Nylon containing abrasives used as a brush material is in great demand mainly as a brush material for power tools, and there is no problem in wet polishing since a cooling step is incorporated. When wet polishing cannot be performed from the viewpoint of rust prevention, etc., only dry polishing is required. In dry polishing, when the above-mentioned nylon brush containing abrasive grains is used, heat is generated in the contact area between the polishing object and the brush material during polishing, although it changes depending on the pressure, number of rotations, and material of the polishing object. When the temperature exceeds 200 ° C., the heat generated by the brush material sometimes causes the nylon of the brush material to be welded to the object to be polished.

[0003]

In order to solve the above-mentioned problems of the nylon brush material, a method of blending a metal wire filament having a weight ratio of% separately from a nylon resin filament has conventionally been adopted. Although the welding of the base material was improved to some extent, the improvement of the base material welding was not complete in the nylon resin filament part, and the possibility of a thermal melting phenomenon still occurred. However, there is a problem in that the production of the brush is complicated and the cost is increased by the amount of the mixed hair.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies on the problems caused by the above-mentioned mixed hair, and as a result, it has been found that the welding of the base material is better when the metal wire is directly buried in the nylon resin than the mixed wire. In addition, it was found that a brush can be manufactured with a bundle of single filaments as compared with the mixture of metal wires, and that the production efficiency is improved. Furthermore, they found that using a stainless steel wire as the core wire was also more durable, and completed a brushed resin filament with a stainless steel core wire embedded in a nylon resin base material containing abrasive grains. I came to.

In this case, as a material of the base material, a nylon resin having flexibility and elasticity (for example, PA-6: melting point of 214 ° C. to 250 ° C.) in a rotary polishing method or the like is preferable. A thermoplastic resin that melts by friction between the material and the object to be polished, for example, an olefin resin such as polyethylene (melting point of 105 ° C. to 120 ° C.) or polypropylene (126 ° C. to 137 ° C.) having excellent acid resistance and flexibility. May be adopted. Further, inorganic fibers other than the thermoplastic resin, for example, glass fibers can be applied.

Further, as a method for polishing the object to be polished with a brush, any of a wet polishing method and a dry polishing method can be applied, but a dry polishing method in which melting of the base material or welding to the object to be polished may occur. Optimally applied to the brush material used for Further, the present invention is applicable to any method of manually or automatically rubbing the object to be polished, and is particularly preferably applied to a rotating brush in which the welding of the thermoplastic resin to the object to be polished easily occurs. .

[0007] Examples of the abrasive grains contained include silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), and diamond. Further, the grain size of the abrasive grains is # 36 (up to 840 μm) to # 2000 (up to 26).
μm) powder-type abrasive (JISR6
002). Various contents can be adopted depending on the degree of polishing of the object to be polished. Furthermore, it is also possible to avoid heat base material stagnation by coating the abrasive grains with a coating material having high thermal conductivity, such as nickel coating, that is, easily radiating heat.

[0008] A stainless steel core wire can be applied as either a stranded wire or a single wire, but a single wire is more advantageous in that it can prevent the coating resin from being damaged by untwisting. Further, since the head of the core wire is exposed in the hair tip cross section, the wire diameter of the core wire is preferably smaller than the particle size of the abrasive grains. In particular,
In the case of using # 320 abrasive grains (having a particle size of 126 μm or less), the stainless steel wire has a smaller diameter of 100 μm.
May be adopted.

[0009] The stainless steel core wire is not limited to the above-mentioned ultrafine wire, but may be one having a diameter corresponding to the diameter of the filament. For example, when manufacturing a filament having a very thick filament diameter, for example, a diameter of 2 mm, the stainless core wire may be thickened in proportion to this.

As described above, by adopting the structure in which the stainless steel core wire is embedded in the resin, not only the welding of the resin can be prevented, but also the rigidity of the resin filament can be remarkably improved. The method, for example, the folded flocking has the advantage that the filament is not broken.

As a method for producing such a resin filament containing a stainless steel core wire, a method of extruding a molten resin serving as a base material and then spraying or impregnating abrasive grains, or a method of mixing the molten resin with abrasive grains, Any one of the methods of extruding integrally with each other can be adopted. However, in the case of the method of spraying or impregnating abrasive grains, since they are only attached to the filament surface, they are easily peeled off, and the performance is remarkably deteriorated particularly when applied to a rotating brush. Therefore, it is preferable to employ a method in which the molten resin and the abrasive grains are mixed and then extruded integrally.

That is, a molten material of a thermoplastic resin as a base material and abrasive grains are mixed, and the mixture is extruded so as to cover a stainless steel core wire, and the extruded wire after the extrusion is cooled. And stabilize. The steps so far are no different from the conventional method for producing a resin filament without a core wire.

However, in the next step, in the case of a resin filament having no core wire, in order to increase the rigidity of the filament, a tension is applied in the drawing step to align the molecular structure and to increase the tensile strength / bending strength. However, in the case of a resin filament containing a stainless steel core wire, this stretching step cannot be adopted because it is a composite material of a different material.

The present inventor has also conducted intensive studies on this point. As a result, it has been found that the heat treatment of the resin filament after extrusion molding and cooling to a degree exceeding the glass transition point causes the molecular structure of the base resin to be aligned. Knowledge was obtained to increase the tensile and bending strength.

As a heating means in this case, the cooled resin filament is passed through a cylinder (cavity) of a heat treatment device and externally heated by conduction heat or radiant heat in this portion.
Alternatively, any means of internal heating by electromagnetic waves (high-frequency heating) may be adopted. The heating temperature at that time is changed depending on the thickness of the filament and the material of the base material. However, the glass transition temperature at which the alignment of the molecular structure of the resin filament is achieved, for example, nylon resin (PA-6: glass transition point 40 to 40) 52 ° C) of 50 to 60 ° C. At this heating temperature, only the pulling force from the extruding machine side acts on the filament and a predetermined tensile force acts on the core wire, so that the molecules of the resin filament can move easily and the molecular structure can be aligned.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a cored resin filament, and FIG. 2 is a view showing the same manufacturing process. As shown in the figure, the cored resin filament 1 of the present embodiment is optimally applied to a dry rotary brush in which the hair is planted on the surface of a roll and the object to be polished is polished at the tip of the roll. The base material 2 contains abrasive grains 3, and a stainless steel core wire 4 is embedded in the center.

The abrasive grains 3 are in the form of powder and have a grain size of # 320 (having a particle size of 126 μm). As the core wire 4 made of stainless steel, an ultrafine wire of 100 μm is used, and a wire having a diameter smaller than that of abrasive grains is used.

As shown in FIG. 2, such a resin filament 1 is prepared by charging a molten material of a nylon resin chip serving as a base material and abrasive grains into a cylinder 9 of an extruder 8 through hoppers 5 and 6 and mixing them. Then, the mixture is extruded from a nozzle 10 so as to cover around a stainless steel core wire 4 passed through the center of a cylinder of an extruder 8, and after the extruded extruded wire is cooled by a cooler 11, Heat treatment is performed at 50 to 60 ° C. in the heat treatment device 12, and the core wire 4 is thermally stretched by the tensile tension applied thereto. Then, the parent resin molecular structure of the nylon resin is aligned, and the cored resin filament 1 for brushes having high tensile strength and bending strength can be obtained. The obtained filament 1 is cut into a desired brush length, bundled and planted on a roll-shaped substrate (not shown) to obtain a rotating brush.

When dry polishing is performed on the object to be polished by the rotating brush manufactured as described above, even if the rotation speed is increased as compared with the conventional case, the resin filament 1 is rubbed between the resin filament 1 and the object to be polished. 1 generates heat, and the heat is radiated to the surroundings through the stainless steel core wire 4 and through the abrasive grains 2 having high thermal conductivity, so that the nylon resin as a base material is welded to the polished object side. Can also be prevented. Further, since the stainless steel core wire 4 is embedded in the center of the base material 2, a rotating brush having high rigidity and excellent durability can be obtained.

[0020]

As is apparent from the above description, according to the present invention, since the abrasive grains are contained in the base material of the thermoplastic resin and the stainless steel core wire is buried, the workpiece to be polished is rotated at a high speed. Even if pressure-rotated, welding of the base resin material can be prevented, and a highly rigid brushed resin filament with a core can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a cored resin filament according to an embodiment of the present invention.

FIG. 2 is a view showing the same manufacturing process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core-containing resin filament 2 Base material 3 Polishing abrasive grain 4 Core wire 8 Extrusion processing machine 11 Cooler 12 Heat treatment machine

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B24D 11/00 B24D 3/00 340 B24D 13/14 D01F 6/90 301

Claims (2)

(57) [Claims] 1. A molten material of a thermoplastic resin as a base material and abrasive grains are mixed, and the mixture is extruded so as to cover a stainless steel core wire, and the extruded wire after extrusion molding is cooled. A method for producing a cored resin filament for a brush, in which the molecular structure of the matrix resin is aligned by performing a heat treatment with a tensile force acting on the core wire . 2. The method according to claim 1 , wherein the temperature of the heat treatment is a temperature of the thermoplastic resin.
2. The method according to claim 1, wherein the temperature is higher than the glass transition point.
A method for producing a resin filament containing a brush core.