JP2021049585A - Polishing pad for cutter - Google Patents

Abstract

To provide a polishing pad for a cutter that can be easily handled and can obtain polishing performance equal to or better than polishing performance which a conventional polishing tool for a cutter made of a strop can obtain.SOLUTION: A polishing pad for a cutter has a disk-like shape and is provided rotatably, and polishes a cutting part of a cutter by a polishing surface formed on an outer peripheral edge thereof, which is constituted of a fiber base body constituted of hydrophobic fiber and polyurethane resin impregnated in the fiber base body, where the polyurethane resin has a flow starting temperature of 150-300°C.SELECTED DRAWING: Figure 3

Description

The present invention relates to a polishing pad for a cutting tool, and more particularly to a polishing pad for a cutting tool which has a disk shape and is rotatably provided and polishes a blade portion of the blade by a polishing surface formed on the outer peripheral edge thereof.

Conventionally, when mass-producing blades such as shavings, first, the end of the metal sent in a strip shape is ground to form a blade, and then a disc-shaped polishing tool for blades is placed above and below the formed blade. There is known an apparatus for performing finish polishing (finish grinding) of a blade portion by positioning and rotating the blade polishing tool (Patent Document 1).
The blade polishing tool of Patent Document 1 is provided in a spirally continuous state on the outer periphery of a rotatable rotating member, and the outer peripheral edge portion of the blade polishing tool contacts the blade portion of the blade for polishing. Consists of a polished surface to perform.
Here, although it is said that the blade grinding device in Patent Document 1 does not require a final polishing process using polished leather, a leather strop made of cow or horse leather is still used for finish polishing of the blade portion. There is a demand for polishing tools for blades using.

Special Publication No. 47-9360

Here, in the case of a polishing tool for cutting tools using the above-mentioned strop, since the strop is derived from a natural product, the quality varies, and the physical properties are likely to fluctuate depending on the environment such as temperature and humidity at the processing site. Therefore, delicate adjustment is required when using it as a polishing tool for cutting tools.
In view of such a problem, the present invention provides a polishing pad for cutting tools that is easy to handle and can obtain polishing performance equal to or higher than that of a polishing tool for cutting tools made of leather strop.

That is, the polishing pad for a blade according to the invention of claim 1 is a polishing pad for a blade that has a disk shape and is rotatably provided and polishes the blade portion of the blade by a polishing surface formed on the outer peripheral edge thereof.
It is composed of a fiber substrate composed of hydrophobic fibers and a polyurethane resin impregnated in the fiber substrate.
The polyurethane resin is characterized in that the flow start temperature is 150 to 300 ° C.

According to the invention of claim 1, by using the hydrophobic fiber for the fiber substrate, the compatibility with the oil-based abrasive used at the time of polishing is improved, and it becomes easy to hold the abrasive on the polished surface. It is possible to obtain finish polishing performance equal to or higher than that of strop, and it can be easily used because its properties are more stable than that of strop.
Further, by setting the flow start temperature of the polyurethane resin within the above range, the polyurethane resin constituting the polishing pad for the blade is softened by the frictional heat when polishing the blade, so that the blade is polished with appropriate elasticity. be able to.

Configuration diagram of razor manufacturing equipment Front view of polishing means Side view of polishing means Secondary electron image photograph by an electron microscope in which the polished surface of the polishing pad for cutting tools of Example 1 and Comparative Example 1 after the use of polishing is magnified 200 times. Photographs of reflected electrons by an electron microscope in which the polished surface of the polishing pad for cutting tools of Example 1 and Comparative Example 1 after polishing is magnified 200 times.

Hereinafter, the illustrated embodiment will be described. FIG. 1 shows a schematic view of a razor blade manufacturing apparatus 2 for manufacturing a razor blade 1 as a blade, and the razor blade manufacturing apparatus 2 is a material supply means 4 for supplying a strip-shaped material 3. , The grinding means 5 for grinding the end portion of the material 3 to form the blade portion 1a of the razor blade 1, the polishing means 6 for finishing and polishing the ground blade portion 1a, and the material 3 on which the blade portion 1a is formed. It is provided with a cutting means 7 that cuts at predetermined intervals to form a razor blade 1. Since such a razor blade manufacturing apparatus 2 itself is conventionally known, detailed description thereof will be omitted except for the configuration described below.
The material supply means 4 is equipped with a coil in which a strip-shaped stainless steel as a material is wound in a roll shape, and the material 3 is sent out from the coil at a predetermined speed. If necessary, holes and notches are formed in the material 3 in advance at predetermined positions, and treatments such as quenching and annealing are also performed.
The grinding means 5 includes a plurality of grinding tools 5a to 5c at positions along the side portions of the material 3 sent by the material supply means 4, and the grinding tools 5a to 5c are end portions of the material 3 to be conveyed. It is arranged so that both sides of the surface are ground diagonally.
Further, the grinding means 5 includes a plurality of grinding tools 5a to 5c, and these grinding tools 5a to 5c perform grinding steps in a plurality of processes such as roughing, intermediate processing, and finishing in order from the upstream side, so that the edge of the material is edged. The portion is ground into a blade portion 1a having an arbitrary shape.

The polishing means 6 is provided on the downstream side of the grinding means 5. In the grinding means 5, for example, the thickness of the blade at 5 μm from the tip of the blade is less than 2 μm, and the thickness of the blade at 20 μm from the tip of the blade is less than 2 μm. The burr (return) generated at the tip of the blade 1a can be removed without breaking the shape of the blade 1a sharpened to a thickness of about 6 μm, and the surface of the blade 1a is roughened to a submicron surface. By polishing smoothly, the sharpness of the sword blade 1 is improved.
FIG. 2 shows a view of the polishing means 6 as viewed from the front, and the polishing means 6 has a rotatably provided cylindrical rotating jig 11 and a substantially disk shape provided on the rotating jig 11. A plurality of polishing pads 12 for cutting tools and a polishing agent supply means (not shown) for supplying polishing agents to the polishing surface 12a formed on the outer peripheral edge of the polishing pads 12 for cutting tools are provided.
As shown in FIG. 2, the rotary jig 11 is provided on one surface and the other surface of the material 3 to be transported in parallel with the transport direction of the material 3, and blade portions 1a are formed at both end portions of the material 3. In this case, rotating jigs 11 are provided on both sides of the material 3.
A plurality of polishing pads 12 for cutting tools are provided at predetermined intervals in the axial direction of the rotating jig 11, and the polishing pads 12 for cutting tools provided on one rotating jig 11 and the other rotating jig 11 are provided. The blade polishing pads 12 are alternately provided at uneven positions so as not to interfere with each other.

As shown in FIG. 3, each of the blade polishing pads 12 has a substantially disk shape having a predetermined thickness, and a circular through hole for mounting on the rotating jig 11 is provided in the center. There is.
Then, by providing the polishing pad 12 for the blade of the rotating jig 11 so as to be offset in the axial direction, it is possible to bring the polishing surface 12a of each polishing pad 12 for the blade into contact with the blade portion 1a from both sides of the blade. It has become.
Further, the rotary jig 11 provided on one side of the material 3 rotates counterclockwise in the direction of the arrow shown, and the rotary jig 11 provided on the other side rotates clockwise in the direction of the arrow shown. Polishing is performed while the contacted polishing surface 12a moves from the tip end portion of the blade portion 1a toward the base portion.
The polishing agent supply means supplies a polishing agent containing an oily component to the polishing surface 12a of each cutting tool polishing pad 12, and a conventionally known polishing agent can be used as the polishing agent. For example, a fat or oil material mixed with abrasive components such as chromium (III) oxide, iron oxide, cerium oxide, zirconium oxide, titanium oxide, magnesium oxide, silicon dioxide, alumina, CBN, and artificial diamond can be used.

When the blade portion 1a is polished by the polishing means 6 having such a configuration, the burrs of the blade portion 1a formed by the grinding means 5 are removed, and the surface of the blade portion 1a is smoothly polished, so that the shaving blade It is possible to improve the sharpness of 1.
The position and angle at which the polishing surface 12a of the blade polishing pad 12 contacts the blade portion 1a can be arbitrarily set, and the blade portion 1a is polished in a plurality of times as in the case of the above-mentioned grinding means 5. You may.
Further, as described in Patent Document 1, it is also possible to continuously provide the polishing surfaces 12a of the blade polishing pad 12 in a spiral shape, and the outer diameters of the blade polishing surfaces 12a are different to form the whole. It is also possible to have a truncated cone shape.

The cutting means 7 cuts the material 3 at equal intervals, whereby the razor blade 1 can be obtained.
Even if a coating means for coating the blade portion 1a to prevent rust or the like or an electrolytic polishing means for performing electrolytic polishing processing is provided between the polishing means 6 and the cutting means 7 or after the cutting means 7. Good.

In the razor blade manufacturing apparatus 2 of the present embodiment, the blade polishing pad 12 used for the polishing means 6 is composed of a fiber substrate made of hydrophobic fibers and a polyurethane resin impregnated in the fiber substrate. It is supposed to use things.
The fiber substrate is a hydrophobic fiber having an oil-friendly property that is familiar with oils such as polyester fiber such as polyethylene terephthalate fiber, polyolefin fiber such as polyethylene fiber and polypropylene fiber, and polyamide fiber such as nylon 6 fiber and nylon 66 fiber. Can be used, and one or more of these fibers can be used.
Fibers are roughly classified into hydrophilic fibers and hydrophobic fibers. Hydrophilic fibers have hydroxyl group (-OH), amino group (-NH), carboxyl group (-COOH), and amide group (-NHCO) hydrophilic groups in their molecular structure, and while they are easily compatible with water, they are oils. Furthermore, when hydrophilic fibers are used as a polishing pad for cutting tools, the fibers swell and soften due to the cooling water during the polishing process, and the fibers lose their stiffness, so that burrs on the blade cannot be removed.
On the other hand, hydrophobic fibers do not have hydrophilic groups or have only a small amount, so they have hydrophobicity and lipophilicity, and are well compatible with polyurethane resins and abrasive components including oils, and retain the abrasives. In addition to being easy, it does not lose its elasticity due to swelling and softening during polishing.
Among the hydrophobic fibers, fibers having a low official moisture content are preferable, fibers having an official moisture content of less than 5% are preferable, and fibers having an official moisture content of 3% or less are more preferable. Specifically, it is desirable to use polyester fiber having particularly excellent lipophilicity and an official moisture content of less than 1%, and particularly preferably polyethylene terephthalate fiber.
As the fineness of each fiber constituting the polishing pad 12 for cutting tools, it is desirable to use 0.7 to 30 dtex, more preferably 1.0 to 20 dtex, and 2.0 to 10 dtex is used. Is even more desirable. It is possible to secure a gap between the fibers and increase the rigidity of the non-woven fabric, which contributes to the improvement of polishing efficiency.
If the fineness is too thicker than 30 dtex, the rigidity of the fiber becomes too high and it becomes difficult to entangle the fiber, and the polishing pad 12 for a blade becomes difficult to bend and becomes coarse and hard. May cause scratches. On the other hand, if the fineness is less than 0.7 dtex and is too thin, the blade polishing pad 12 is softened, and the tip of the polished blade portion 1a is rounded to reduce the sharpness.

When the fiber length of each fiber is in the range of 40 to 80 mm, the passability of the carding machine (carding machine) that aligns the fibers at the time of manufacturing the non-woven fabric and the entanglement between the fibers are good, and at the time of polishing. It is preferable because the fibers are appropriately removed when the polished surface 12a is worn and clogging can be suppressed.
If the fiber length is less than 40 mm, although it depends on the basis weight and thickness of the non-woven fabric, it is difficult for the fibers near the front surface to reach the back surface during needle punching, and the non-woven fabric sheet is likely to be delaminated, which is not preferable.
Further, in the range significantly exceeding 80 mm, the end portion of the fiber is unlikely to appear during polishing, and when the polished surface 12a is worn by the polishing process, the fiber cannot be detached and clogging is likely to occur, so that the blade portion 1a It is not preferable because it causes polishing burn.

Next, as the structure of the fiber substrate constituting the polishing pad 12 for cutting tools, a non-woven fabric using the above fibers can be used. The production of non-woven fabrics can be divided into fleece formation and fleece fiber entanglement.
The fleece forming method is not particularly limited, and examples thereof include a dry method, a wet method, a spunbond method, a melt blown method, and an airlaid method. The fleece fiber entanglement method is not particularly limited, and examples thereof include a chemical bond method (immersion method, spray method), a thermal bond method, a needle punch method, and a water flow entanglement method (water jet method). ..
Each of these methods can be combined arbitrarily. For example, a fleece in which the direction of the fibers is adjusted is formed by a card machine by a dry method, a plurality of the obtained fleeces are laminated, and the fibers are entangled by a needle punch. Can produce a non-woven fabric.
At this time, the direction of the fibers when configured as the polishing pad 12 for a cutting tool is oriented on a two-dimensional plane so as to face in a plane orthogonal to the axial direction of the rotating jig 11.
With such a configuration, the end portion of the fiber can be exposed to the polishing surface 12a on the outer peripheral edge of the polishing pad 12 for a blade, and when the blade portion 1a is polished, the blade portion 1a is exposed at the end portion of the fiber. It becomes possible to perform polishing.
In addition, with such a configuration, the abrasive can easily enter between the tip of the fiber and the tip of the fiber, and since this can be held, the effect of the abrasive can be easily obtained. can get.

It is desirable to use a physical entanglement method as the entanglement integration method of the non-woven fabric. As a physical entanglement method, a water jet punch method or the like is generally used in addition to the needle punch method, but in this example, the needle punch method was used.
In the needle punch method, a needle (needle) having a plurality of portions for hooking and entwining a thread, a fork needle having a tip shaped like a fork, or the like can be used. Conditions such as the speed (number of strokes), needle density, and stroke distance of the machine at this time may be appropriately selected according to the basis weight and thickness of the web.
Further, in the case of a method such as a thermal bond method or a chemical bond method in which a binder fiber or an adhesive is put in a web and heated under pressure to integrate, when the fused portion is exposed on the polished surface, the contact with the blade portion 1a is strong. In addition to being prone to polishing burns and polishing scratches on the blade portion 1a, it is not preferable because the fibers are not easily detached during the polishing process and clogging occurs, which is likely to cause polishing burns.

The web used for the non-woven fabric is formed into a sheet by arranging the fibers using a known card machine, so that the fibers are horizontally arranged on the flat surface of the sheet. Therefore, the outer peripheral edge of the polishing pad 12 for cutting tools is polished. This is preferable because the fiber ends are easily exposed on the surface 12a.
On the other hand, in the spunbond method and the melt blow method in which the non-woven fabric is directly obtained after spinning without creating a web, the fiber ends are hard to be exposed on the polished surface 12a because the fibers are continuous long fibers, and the base material of the razor blade polishing pad Is not preferable.

Next, as the polyurethane resin constituting the polishing pad 12 for cutting tools, a commercially available product can be used in addition to the one manufactured by a conventionally known method. Examples thereof include Chrisbon (DIC Corporation), Samplen (Sanyo Chemical Industries, Ltd.), and Resamine (Dainippon Fine Chemical Industries, Ltd.).
Further, as the polyurethane resin, it is desirable that the flow start temperature is 150 to 300 ° C, and more preferably 155 to 250 ° C. By setting the flow start temperature in such a range, the resin portion can be appropriately softened by friction when polishing the blade portion 1a, and a high polishing result can be obtained.
On the other hand, if the flow start temperature is less than 150 ° C., the resin component tends to adhere to the polished surface 12a due to heat generated during the polishing process, and the appearance of the polished blade portion 1a and the sharp tip shape are impaired. It affects the sharpness.
On the other hand, when the flow start temperature exceeds 300 ° C., the resin portion maintains a hard state, it is difficult to follow the shape of the blade portion 1a, and it is difficult to remove burrs on the blade portion 1a.
As a method for deriving the flow start temperature of the resin, it can be derived from the extrapolation point of the point where the phase angle sharply rises from the temperature dependence curve obtained by using the dynamic viscoelasticity measuring device. .. RSA-III (TA Instruments Japan Co., Ltd.) can be used as the dynamic viscoelasticity measuring device.

The thickness of the polishing pad 12 for cutting tools produced by using the above material is preferably in the range of 2.0 to 10.0 mm. If it is less than 2.0 mm, the thickness is too small, the rigidity of the polishing pad 12 for cutting tools is lowered, and the product life is shortened, which is not preferable.
Further, when the thickness exceeds 10 mm, the amount of the resin to be impregnated tends to be different between the center side and the surface side of the thickness of the non-woven fabric sheet, the resin becomes coarse and dense on the polished surface 12a, and the contact with the blade portion 1a is non-uniform. It is not preferable because it becomes.

The density of the polishing pad 12 for cutting tools ^{is preferably 0.3 to 0.8 g / cm 3,} and more preferably 0.35 to 0.75 g / cm ^3. With such a density, the entire polishing pad 12 for cutting tools has appropriate rigidity, which contributes to the improvement of polishing efficiency.
On the other hand, if the density is ^{less than 0.3 g / cm 3,} the rigidity of the polishing pad for blades is inferior, and the ability to remove burrs on the blade portion 1a during polishing is reduced. Further, if it exceeds 0.8 g / cm ³ , the voids between the constituent fibers are reduced, and the clogging of the polishing debris and the holding amount of the abrasive material are reduced during polishing, which causes polishing burn. ..

The cross-sectional compression ratio, which is the compression ratio of the polishing pad 12 for cutting tools with respect to the cross section in the thickness direction, is preferably 1.0 to 6.0%, more preferably 1.3 to 5.0%. With such a cross-sectional compression ratio, the followability of the polished surface 12a when polishing the blade portion 1a can be improved.
On the other hand, if the cross-sectional compression ratio is less than 1.5%, the amount of deformation of the polished surface 12a is small and the blade portion 1a is easily scratched. At that time, the tip of the blade portion 1a is rounded and the sharpness is lowered.
The cross-sectional compression ratio can be measured by the method described in Examples. Further, the cross-sectional compressibility can be adjusted by adjusting the above density.

The cross-sectional A hardness of the polishing pad 12 for cutting tools with respect to the cross section in the thickness direction is preferably 50 to 90 °, more preferably 53 to 85 °, and even more preferably 55 to 80 °.
When the cross-sectional A hardness is 50 ° or more, the life of the cutting tool polishing pad 12 tends to be further improved. Further, when the cross-sectional A hardness is 90 ° or less, the occurrence of polishing scratches is suppressed, and the polishing quality of the obtained blade portion 1a of the razor blade 1 tends to be further improved.
The danmen A hardness can be measured by the method described in Examples. Further, the hardness of the cross section A can be adjusted by, for example, the type of resin used and the amount of adhesion.

The cross-sectional compressive elastic modulus of the polishing pad 12 for cutting tools with respect to the cross section in the thickness direction is preferably 70 to 98%, more preferably 75 to 95%, and further preferably 80 to 92%.
When the cross-sectional compressive elastic modulus is within the above range, the adhesion between the blade polishing pad 12 and the blade portion 1a becomes better.
The cross-sectional compressive elastic modulus can be measured by the method described in Examples. Further, the cross-sectional compressive elastic modulus can be adjusted depending on the type of resin used.

The content of the fiber substrate in the total mass of the polishing pad 12 for cutting tools is preferably 30 to 90 wt%, and more preferably 50 to 85 wt%.
The content of the fiber substrate (the amount of the resin solution adhering to the fiber substrate) is determined after adjusting the polyurethane resin concentration in the polyurethane resin solution in which the fiber substrate is immersed or after sufficiently immersing the fiber substrate in the polyurethane resin solution. The resin solution can be adjusted to a desired amount by squeezing the resin solution from the fiber substrate to which the resin solution is attached using a mangle roller that can pressurize between a pair of rollers.
By containing the fibers in this range, it is easy to efficiently hold the abrasive between the fibers to which the polyurethane resin is attached, and the fiber ends can be exposed on the polished surface 12a.

The cutting tool polishing pad 12 has a specific fiber density in the thickness direction thereof. In the present specification, the fiber density is represented by the number of fibers per unit area in the cross section of the polishing pad 12 for cutting tools, and the unit can be, for example, a line / mm ² .
Fiber density of cutlery polishing pad 12 is preferably 200 to 2100 present / mm ^2, and more preferably from 350 to 1,650 present / mm ^2.
When the fiber density is within this range, the fiber ends are sufficiently exposed on the polished surface 12a, a large amount of abrasive can be held in the gaps between the fibers, and the number of contact points in contact with the blade 1a is large. By increasing the number, the contact with the blade portion 1a becomes mild, and the occurrence of polishing scratches is suppressed.
In the following examples, the method for measuring the fiber density using a scanning electron microscope will be described in detail, but in addition to the method adopted in the examples, a method using a reflective optical microscope and the like are constant in the cross section of the non-woven fabric. The method is not particularly limited as long as the fiber density can be calculated by grasping the number of fibers existing in the area.

Hereinafter, a method for manufacturing the polishing pad 12 for cutting tools will be described.
First, the hydrophobic fiber substrate constituting the polishing pad 12 for a knife is prepared. As described above, as the hydrophobic fiber substrate, a non-woven fabric using a fiber having hydrophobicity such as polyester, polyamide, polypropylene, acrylic, and lipophilicity can be used, and can be obtained by a conventionally known method.
Next, the polyurethane resin is impregnated into the hydrophobic fiber substrate, and when the impregnated resin is dried, it is cut into a disk shape to obtain a polishing pad 12 for a knife. Here, in order to make the thickness uniform, one side or both sides of a circular surface in terms of top view may be sliced or heat-pressed.

Table 1 above is a table summarizing the experimental results of Examples 1 to 3 according to the present invention and Comparative Products 1 and 2 used for comparison. The following three types of experiments were performed respectively.

Experiment 1: Evaluation of polishing The blade 1a of the sword blade 1 is polished for 30 seconds using the tool polishing pad 12 while using a polishing agent (Bushcraft # 12000 white), and burrs on the blade 1a after polishing are removed. The presence or absence of deposits is observed by a backscattered electron image of a scanning electron microscope (JSM-5500LV, manufactured by JEOL Ltd.), and the deposits are observed by gas chromatography mass spectrometry (gas chromatograph device: Agilent Technologies, Ltd .: Agilent 6890N). , Mass spectrometer: JEOL Ltd .: JMS-Q100OGCK9).

Experiment 2: Sharpness evaluation A cutting load tester holds both ends of the test piece (elongated wool felt), and the razor blade 1 obtained as a result of polishing in Experiment 1 is lowered from above to the test piece. The resistance value at the time of cutting was measured and compared with the resistance value of a razor blade polished with a polishing tool for cutting tools consisting of a strop.

Experiment 3: Observation of the state of the polishing agent remaining on the polishing surface 12a of the polishing pad 12 for cutting tools after polishing Scanning the polishing surface 12a of the polishing pad 12 for cutting tools of the example product and the comparative example product used for polishing in Experiment 1 Observed by a secondary electron image magnified 200 times with an electron microscope (JSM-5500LV manufactured by Nippon Denshi Co., Ltd.) and a reflected electron image, the surface condition of the polished surface 12a after polishing and the polishing agent on the polished surface 12a. The state of adhesion was observed.

Further, according to the above experiment, the following physical property values were measured for the polishing pads for cutting tools of Examples 1 to 3 and Comparative Examples 1 and 2, respectively, as follows.
[Cross-section A hardness]
A 5 mm × 10 mm test piece is cut out from the circular surface of the polishing pad for cutting tools, and the test piece is placed on the measuring table so that the thickness cross section of the polishing pad for cutting tools is the upper surface (measurement surface). Subsequently, a pressing needle (cylindrical indenter having a diameter of 0.79 mm) was pressed against the center of the test piece, and the cross-sectional A hardness of the polishing pad for cutting tools was measured from the pressing depth of the pressing needle 30 seconds later. As a measuring device, a durometer type A was used. This was performed three times, and the cross-sectional hardness A was determined from the arithmetic mean.
[Cross-section compressibility and cross-section compressibility]
A 5 mm x 10 mm test piece is cut out from the circular surface of the polishing pad for cutting tools, and the test piece is placed on the top surface (measurement surface) so that the thickness cross section of the pad is the top surface (measurement surface). It was installed in a circular shape), and the compressibility and compressive elastic modulus of the polishing pad for cutting tools were measured.
Specifically, the thickness t0 after being pressurized with the initial load for 30 seconds was measured, and then the thickness t1 after being left for 5 minutes under the final load was measured. After removing all the loads and leaving for 1 minute, the thickness t0'was measured after pressurizing again with the initial load for 30 seconds. At this time, the initial load was 100 g / cm ² and the final load was 1120 g / cm ² .
The compressibility was calculated by the following formula (1), and the compressive elastic modulus was calculated by the following formula (2).
Formula (1): Compression rate (%) = (t0-t1) / t0 × 100
Formula (2): Compressive modulus (%) = (t0'-t1) / (t0-t1) x 100
〔thickness〕
Using a shopper type thickness measuring instrument (pressurized surface: circular with a diameter of 1 cm), the thickness of the polishing pad for cutting tools was measured in accordance with Japanese Industrial Standards (JIS K 6505).
Specifically, three sample pieces cut out to a size of 10 cm × 10 cm were prepared, and each sample piece was set at a predetermined position on a thickness measuring instrument, and then a load of ^{480 g / cm 2 was applied.} The pressure surface was placed on the surface of the sample piece, and the thickness was measured after 5 seconds. The thickness of one sample piece was measured at five points, the arithmetic mean was calculated, and the arithmetic mean of three sample pieces was obtained.
〔density〕
A polishing pad for cutting tools is cut into a size of 10 cm × 10 cm, used as a sample piece, and the mass thereof is measured, and the density (bulk density) (g / cm ³ ) of the polishing pad for cutting tools is calculated from the volume obtained from the above size and the above mass. did.
[Fiber density]
The thickness cross section of the polishing pad for cutting tools was magnified 500 times using a scanning electron microscope (JSM-5500LV, manufactured by JEOL Ltd.), and 9 places were randomly observed.
The number of exposed fiber ends was counted from this image, the average value of the number of fiber ends was obtained, and this was converted into the number of fiber ends per ^{unit area (mm 2) to calculate the fiber density.}

The polishing pad 12 for cutting tools according to Example 1 was manufactured as follows. First, raw cotton made of polyethylene terephthalate fiber (fineness 2.2 dtex, average fiber length 51 mm) is passed through a blending cotton machine, and then a fleece is formed by a card (carding machine) to adjust the direction of the fibers and laminate them. , A hydrophobic fiber substrate made of a polyethylene terephthalate non-woven fabric was prepared by entwining the fibers with a needle punch.
Subsequently, the obtained non-woven fabric is immersed in a resin dispersion of ether-based polyurethane having a flow start temperature of 160 ° C., and then a surplus resin dispersion is applied using a mangle roller capable of pressurizing between a pair of rollers. After squeezing, the non-woven fabric was impregnated with the resin dispersion almost uniformly. Then, the resin dispersion was dried to obtain a resin-impregnated nonwoven fabric.
Then, one side of the obtained resin-impregnated non-woven fabric was sliced and cut into a disk shape to obtain a polishing pad 12 for a knife.
The manufactured tool polishing pad 12 of Example 1 has a thickness of 5.5 mm, a density of 0.35 g / cm ³ , a cross-sectional compressibility of 85.0%, a cross-sectional compressibility of 3.0%, and a cross-sectional A hardness of 68.0 °. The fiber density was 1197 fibers / mm ² .
The content of hydrophobic fibers in the polishing pad 12 for cutting tools was 70 wt% with respect to the total mass.

Regarding the polishing pad 12 for cutting tools according to Example 2, except that a resin dispersion of ether-based polyurethane having a flow start temperature of 195 ° C. is used in the production of the resin-impregnated non-woven fabric constituting the polishing pad 12 for cutting tools. A resin-impregnated non-woven fabric was obtained in the same manner as in Example 1.
The manufactured polishing pad 12 for cutting tools of Example 2 has a thickness of 4.5 mm, a density of 0.45 g / cm ³ , a cross-sectional compressibility of 85.0%, a cross-sectional compressibility of 2.5%, and a cross-sectional A hardness of 75.0 °. The fiber density was 392 / mm ² .
The content of hydrophobic fibers in the polishing pad 12 for cutting tools was 35 wt% with respect to the total mass.

Regarding the polishing pad 12 for cutting tools according to Example 3, except that a resin dispersion liquid of polycarbonate-based polyurethane having a flow start temperature of 225 ° C. is used in the production of the resin-impregnated non-woven fabric constituting the polishing pad 12 for cutting tools. A polishing pad for cutting tools was obtained in the same manner as in Example 1. Subsequently, after slicing one side of the obtained resin-impregnated non-woven fabric, heat pressing was performed for 300 seconds under the conditions of a temperature of 130 ° C. and a pressure of 4 MPa, and cutting was performed in a disk shape to obtain a polishing pad for cutting tools. ..
The manufactured polishing pad 12 for cutting tools of Example 3 has a thickness of 4.51 mm, a density of 0.5 g / cm ³ , a cross-sectional compressibility of 84.1%, a cross-sectional compressibility of 1.4%, and a cross-sectional A hardness of 80.5 °. The fiber density was 1362 fibers / mm ² .
The content of hydrophobic fibers in the polishing pad 12 for cutting tools was 78 wt% with respect to the total mass.

Regarding the polishing pad for cutting tools according to Comparative Example 1, a resin dispersion of ether-based polyurethane having a flow start temperature of 140 ° C. was used in the production of the resin-impregnated non-woven fabric constituting the polishing pad 12 for cutting tools, and the polishing pad for cutting tools was used. A polishing pad for cutting tools was manufactured in the same manner as in Example 1 except that the content of the hydrophobic fiber in the non-woven fabric was 20 wt% with respect to the total mass.
The manufactured polishing pad for blades of Comparative Example 1 had a thickness of 4.5 mm, a density of 0.34 g / cm ³ , a cross-sectional compressibility of 94.0%, a cross-sectional compressibility of 1.7%, and a cross-sectional A hardness of 62.5 °. The fiber density was 254 fibers / mm ² .
The content of hydrophobic fibers in the polishing pad for cutting tools was 20 wt% with respect to the total mass, and the flow start temperature of the polyurethane resin constituting the polishing pad for cutting tools was 140 ° C.

Examples of the polishing pad for cutting tools according to Comparative Example 2 except that a resin dispersion of ether-based polyurethane having a flow start temperature of 140 ° C. is used in the production of the resin-impregnated non-woven fabric constituting the polishing pad 12 for cutting tools. A polishing pad for cutting tools was manufactured in the same manner as in 1.
The manufactured polishing pad for blades of Comparative Example 2 had a thickness of 4.54 mm, a density of 0.35 g / cm ³ , a cross-sectional compressibility of 94.0%, a cross-sectional compressibility of 1.7%, and a cross-sectional A hardness of 60.5 °. The fiber density was 1176 fibers / mm ² .
The content of hydrophobic fibers in the polishing pad for cutting tools was 70 wt% with respect to the total mass, and the flow start temperature of the polyurethane resin constituting the polishing pad for cutting tools was 140 ° C.

Explaining the result of Experiment 1, in Experiment 1, the blade portion 1a of the razor blade 1 is polished using the polishing pad 12 for a blade while using a polishing agent, and the burr of the blade portion 1a of the blade 30 seconds after the start of polishing is performed. The presence or absence of deposits and deposits was observed with an optical microscope or SEM reflected electron image.
The evaluation method was evaluated as ◯ when no burrs or deposits were found on the blade portion 1a, and as x when burrs or deposits were found.
As a result of the experiment, with respect to the razor blade 1 which was polished using the polishing pads 12 for blades of Examples 1 to 3, no burrs or deposits were observed on the blade portion 1a, and a good polished surface was obtained.
On the other hand, burrs and deposits were observed on the blade portion 1a polished by the blade polishing pad 12 of Comparative Examples 1 and 2, and deposits were observed on the blade portion 1a polished by the blade polishing pad 12 of Comparative Example 2. Was recognized.
Here, in the deposits of the razor blade 1 polished by using the blade polishing pads 12 of Comparative Examples 1 and 2, powdery convex deposits and band-shaped pigments are deposited on the tip of the blade portion 1a. It was a black deposit. When the blades to which the deposits were attached and the blade polishing pads 12 of Comparative Examples 1 and 2 were thermally analyzed by gas chromatography-mass spectrometry (GC / MS), the deposits and the blade polishing pads of Comparative Examples 1 and 2 were obtained. Since the peak of the same organic substance component was detected in the above, it was found that the deposit was an eluate of the polyurethane resin component of the pad.
From this, it is presumed that when the flow start temperature of the resin is lower than 150 ° C., the resin portion of the polyurethane resin is melted during polishing, and as a result, the eluate adheres to the razor blade 1.

To explain the results of Experiment 2, in Experiment 2, a cutting load tester was used to hold the test piece (elongated wool felt) at both ends, and the blade obtained as a result of polishing was lowered from above. The resistance value when the test piece was cut was measured.
Then, the cutting resistance value of the blade polished with the polishing pad for the blade made of leather strop is set to 1, and when the measured cutting resistance value is less than 1, the sharpness is better than the conventional one. Conceivable.
As a result of the experiment, the cutting resistance value of each of the razor blades 1 polished by using the blade polishing pads 12 of Examples 1 to 3 was 1 or less, and good sharpness was obtained.
On the other hand, the cutting resistance value of the razor blade 1 polished by using the blade polishing pads 12 of the comparative products 1 and 2 exceeds 1, and the sharpness is lower than that when the leather grind is used. The result was that it did. It is considered that this is due to the burrs and deposits on the blade recognized in Experiment 1.

Explaining the results of Experiment 3, the polishing surface 12a of the polishing pad 12 for cutting tools of Example 1 and Comparative Example 1 used for polishing in Experiment 1 was subjected to a secondary electron image (200 times) and a backscattered electron image (200 times) of a scanning electron microscope. 200 times), and the surface condition of the polishing pad after the use of polishing and the adhesion state of the polishing agent to the polishing surface 12a were observed.
Since the reflected electron image is atomic number dependent, those with a large atomic number such as abrasive grain components are bright, and those with a small atomic number such as organic components are dark images. When the fiber was bright, it was evaluated as ◯, and when the fiber was not bright, it was evaluated as ×.
In Examples 1 to 3 and Comparative Example 2, since the content of the hydrophobic fibers is larger than 30 wt% with respect to the total mass of the polishing pad for cutting tools, polishing is performed as is clear from the secondary electron image photograph of FIG. The fiber end portion could be confirmed on the surface 12a, and as is clear from the backscattered electron image photograph of FIG. 5, it was confirmed that a large amount of abrasive grain components brightly shown on the fiber surface were fixed.
On the other hand, as is clear from FIG. 4, the comparative product 1 has a large amount of resin and few voids, so that the abrasive grain component is thinly spread over the entire polished surface 12a as shown in FIG.
As described above, according to Experiment 3, since the polishing pad 12 for cutting tools according to the embodiment holds the polishing agent between the tip portion of the fiber and the tip portion of the fiber, the polishing agent is good even during polishing. It is presumed that it can be retained in the area and contributes to the improvement of sharpness.

The blade polishing pad 12 of the above embodiment is designed to polish the blade portion 1a of the razor blade 1 as a blade, but it goes without saying that other blades can also be polished.

1 Razor blade (cutlery) 1a Blade part 2 Razor blade manufacturing equipment 3 Material 5 Grinding means 6 Polishing means 11 Rotating jig 12 Polishing pad for cutting tool 12a Polished surface

Claims (3)

It is a polishing pad for blades that has a disk shape and also polishes the blade portion of the blade with the polishing surface formed on the outer peripheral edge thereof.
It is composed of a fiber substrate composed of hydrophobic fibers and a polyurethane resin impregnated in the fiber substrate.
A polishing pad for cutting tools, wherein the flow start temperature of the polyurethane resin is 150 to 300 ° C. A claim characterized in that at least a part of the hydrophobic fibers constituting the fiber substrate is oriented horizontally with respect to a flat surface of a polishing pad for a cutting tool, and the end portion of the fiber is exposed to the polishing surface. Item 2. The polishing pad for cutting tools according to Item 1. The polishing pad for cutting tools according to claim 1 or 2, wherein the content of the hydrophobic fibers is 30 to 90 wt% with respect to the total mass of the polishing pad for cutting tools.

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