JPS6354513B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an abrasive material, particularly a method for producing an abrasive material suitable for polishing and polishing lenses, cathode ray tubes, glass plates, etc.

Conventionally, as a method for polishing lenses, a pad of low-expansion polyurethane foam containing abrasive grains obtained by foaming a raw material containing polyurethane foam containing abrasive grains such as cerium oxide or zirconium oxide is used as an abrasive material. A known method is to polish the lens while replenishing the contact surface between the lens and the pad with water in which abrasive grains such as cerium oxide are dispersed.

However, in this method, the abrasive grains of cerium oxide, zirconium oxide, etc. contained in the polyurethane low foam foam are embedded and fixed in the foam, so the abrasive grains on the surface side of the pad cannot be polished. Although it can be used effectively, the abrasive grains inside the pad do not flow toward the surface and do not work during polishing. There is a problem that it cannot be used effectively for polishing. Furthermore, in polyurethane foam pad abrasive materials in which such abrasive grains are blended and dispersed, the amount of abrasive grains cannot be increased due to the effect on the foaming reaction and the physical properties of the foam. Due to the constraints of
Obtained foam properties (flexibility, hardness, strength, etc.)
There is a problem that the degree of freedom of polishing is limited, and it is also difficult to adjust the roughness of the pad (abrasive material). In addition, since this abrasive material is made of polyurethane foam pad, it has micropores (open cells), and these micropores are useful for retaining and releasing the abrasive dispersion liquid that is replenished during polishing. However, since the size and distribution of these micropores are non-uniform, there is also the problem that retention and release of the dispersion become uneven.

In addition, as a method of polishing cathode ray tubes and glass plates, wool felt is conventionally used and polished while replenishing an abrasive dispersion similar to lens polishing, but since wool felt is a natural fiber, There are problems such as the quality varies widely depending on the production area, harvest time, etc., and the process must be adjusted to absorb this variation during polishing.

The present invention was made in view of the above circumstances, and consists of attaching abrasive grains to a soft polyurethane foam having a three-dimensional network skeleton without a cell membrane, and polishing the abrasive grains to
Compress the soft polyurethane foam to 1/2 to 1/15 of the original size using a heat press heated to a temperature of ℃,
By permanently deforming, the amount of abrasive grains attached can be easily adjusted, and the hardness and flexibility can be adjusted to suit the purpose of polishing. The surface of wood, plastic, etc. can be well polished or polished, and most of the attached abrasive grains act as fluid abrasive grains, so expensive abrasive grains can be effectively used for polishing, and conventional A method for producing an abrasive material that can reliably and easily produce an abrasive material that has the characteristics of reducing or eliminating the use of expensive abrasive grain dispersions during polishing. It provides:

The present invention will be explained in more detail below.

The method for manufacturing an abrasive material of the present invention involves compression molding a foam lattice with abrasive grains attached to it. By using this type of flexible polyurethane foam without a cell membrane, the cell size can be adjusted in various ways, and the cell size can be made almost uniform, so that the surface It is easy to adjust the degree of roughness to suit the purpose of polishing, and the abrasive grains can be easily and evenly attached to the foam skeleton lattice, and by compression molding this soft polyurethane foam without a cell membrane, The obtained abrasive material has good water absorption properties since it does not have a cell membrane, and when polishing a lens or the like while replenishing water or water in which abrasive grains are dispersed, it has excellent retention and release performance for these media. Polyurethane foam with a three-dimensional network skeleton structure without a cell membrane can be produced by subjecting a polyurethane foam having a normal cell membrane to post-treatments such as heat treatment and hydrolysis treatment, or by adding a compound system without a cell membrane during foaming. It can be manufactured by a method such as foaming using a foam.

Various types of abrasive grains can be used depending on the purpose of polishing, and there is no particular control on the type of abrasive grains attached to the foam, but for example, for polishing lenses, cathode ray tubes, plate glass, etc. Cerium oxide, zirconium oxide, etc. are used, and chromium oxide, iron oxide, fine powder alumina, emery, corundum, etc. are also used. Note that the particle size of the abrasive grains can be appropriately selected depending on the purpose of use.

The method for attaching the abrasive grains to the foam is as follows:
Generally, abrasive grains are mixed with water or adhesive liquid (latex,
A method can be adopted in which the foam is dispersed in an emulsion (solvent type), immersed in this dispersion, passed through a squeezing roller or centrifugal separator to obtain the desired amount of impregnation, and then dried under drying conditions commensurate with the impregnating liquid. This causes the abrasive grains to adhere to the entire foam surface and internal lattice.

In the present invention, the foam to which abrasive grains have been attached in this manner is compression molded, and in this case, the compression ratio is selected to obtain the hardness, flexibility, and thickness depending on the purpose of use. Generally, a heating compression molding method is employed, and by compression molding at a temperature of 130 to 220°C and a compression rate of 1/2 to 1/15 of the original size of the foam, an abrasive with good properties can be reliably obtained. In other words, when the compression ratio is lower than 1/2, especially when the compression ratio is 1, i.e. in an uncompressed state, the abrasive material is too soft and unsuitable for polishing lenses, cathode ray tubes, glass plates, etc. Since the foam cell density (number of cells per unit length) is sparse, the amount of abrasive grains exposed on the surface is small.
Moreover, during polishing, the abrasive grains hit the polished surface unevenly, and the size (volume) of the open cells is large.
If water or abrasive dispersion is supplied during polishing, appropriate retention and release of these particles cannot be achieved. Furthermore, if the compression ratio is greater than 1/15, the abrasive material becomes too hard, and even if water and abrasive dispersion are supplied during polishing, the retention and release performance of these materials will be poor. On the other hand, by setting the compression ratio to 1/2 to 1/15, it has good stiffness, moderate hardness, flexibility, and surface roughness, and the appropriate amount of abrasive grains are applied to the surface to be polished during polishing. It is possible to reliably produce an abrasive material that hits in a uniform state and has excellent retention and release performance when water or an abrasive dispersion is supplied.

Next, to explain the embodiments of the abrasive material of the present invention shown in the drawings, FIG. 1 shows an abrasive material 1 formed into a flat plate shape as a whole, and FIG. FIG. 3 shows an abrasive material 1 with a large number of through holes 3 formed therein. Second
As shown in the figure, by forming unevenness 2 on the abrasive material 1 (the unevenness 2 may be formed not only on one side of the abrasive material 1 but also on both sides, and the shape of the unevenness 2 is also limited to a wavy shape). ), during polishing, the polishing pressure ensures that the convex portions contact the surface of the object to be polished, and water and dispersion are well retained in the concave portions, achieving very good polishing. . Incidentally, the unevenness 2 can be formed by a method such as using a press plate provided with an embossing pattern. In addition, as shown in FIG.
By forming the through-holes 3 in , it is possible to improve the retention and release performance of water and abrasive grain dispersion. The through-holes 2 are formed after compression molding by using a drill, punching die, or the like to drill through-holes 2 of a desired size and desired degree of dispersion.

Fig. 4 is an enlarged view of a part of the abrasive material 1 of the present invention, which is an example of a product made by compression molding a polyester polyurethane foam having a three-dimensional network skeleton structure without a cell membrane. This is a cross-sectional view of the grating 1a of the abrasive material 1, showing a state in which abrasive grains 4 are attached to the surface of the grating 1a.

The abrasive material of the present invention can be used for polishing or polishing glass surfaces such as lenses and glass plates, or surfaces of metals, wood, and plastics, depending on the type of abrasive grains used, the hardness of the abrasive material, the surface roughness, etc. However, as a polishing method, a conventional method such as a manual polishing method, a method of attaching it to a polishing machine and polishing it, etc. can be adopted. In this case, polishing can be performed while supplying water or water with abrasive grains dispersed therein, if necessary.

In the method for producing an abrasive material of the present invention, abrasive grains are attached to a lattice of a soft polyurethane foam having a three-dimensional network skeleton structure without a cell membrane, and this is compression-molded. It is easy to adjust the adhesion amount according to the purpose of polishing, and the hardness of the abrasive can be increased by appropriately selecting the type of foam material, the type of adhesive used to adhere the abrasive grains, and the compression ratio. The hardness, flexibility, and roughness of the polished surface can be adjusted to suit the purpose of polishing, and the desired polishing purpose can therefore be achieved reliably. Furthermore, even if the abrasive grains are attached to the foam lattice via an adhesive, the adhesion force is not strong, and most of the abrasive grains act as fluid abrasive grains due to the polishing pressure during polishing. Therefore, expensive abrasive grains are effectively used for polishing purposes. Furthermore, when polishing is performed while supplying an abrasive grain dispersion, the amount of dispersion used can be reduced, or it is sufficient to simply replenish water.
Economical. Furthermore, according to the abrasive manufacturing method of the present invention, an abrasive having the above-mentioned good performance can be reliably and easily manufactured.

Next, specific examples of the present invention will be shown.

Example The following formulation cerium oxide (Celico manufactured by Nippon Metal Chemical Co., Ltd.)
50 parts by weight of acrylic acid emulsion (Sumitex AMH-3000, manufactured by Sumitomo Chemical Co., Ltd.) 200 parts water 50 parts cerium oxide-containing solution was added to a thickness of 10 mm and 30 cells/
After impregnating a 25 mm soft polyester polyurethane foam with a three-dimensional network skeleton structure without a cell membrane, the amount of cerium oxide deposited was reduced to three times the weight of the foam. This was dried at 100°C, and then compression molded to 1.25 mm using a spacer in a heat press at 180°C (compression rate: 87.5%).

This abrasive material has appropriate flexibility, hardness, surface roughness, and microporosity for lenses, and cerium oxide acts effectively as a fluid abrasive grain during lens polishing.
It is suitable as an abrasive material for lenses.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views showing one embodiment of the present invention, and FIG. 4 is a partially omitted enlarged perspective view showing an embodiment in which a flexible polyurethane foam without a cell membrane is used as the foam. FIG. 5 is an enlarged cross-sectional view of the foam lattice. 1... Abrasive material, 2... Unevenness, 3... Through hole, 4
...abrasive grains.

Claims (1)

[Claims] 1. Abrasive grains are attached to a soft polyurethane foam that has a three-dimensional network skeleton without a cell membrane, and
A method for producing an abrasive material, which comprises compressing the soft polyurethane foam to 1/2 to 1/15 of its original size using a hot press heated to a temperature of 130 to 220°C to permanently deform it.