JPH068377B2 - Impregnating liquid for porous grindstone - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impregnating liquid used for producing a porous grindstone mainly composed of a polyvinyl alcohol (PVA) formalized resin as a basic binder, and more specifically to the hardness and water resistance of the porous grindstone. , An impregnating liquid for improving machinability.

[0002]

Prior Art and Problems to be Solved by the Invention PVA
The formalized resin-based grindstone is porous and rich in elasticity, and has a characteristic such as a good finished surface especially in curved surface polishing, but on the contrary, it is easily worn and has poor machinability. Further, it has a property that it is softened by water, water cannot be used as a cooling liquid used for preventing overheating of a surface to be polished, and there is a drawback that wet polishing is generally difficult.

As a method for solving this, (1) a method of preliminarily mixing an initial condensate of a thermoplastic resin with a PVA resin to form a formal (for example, JP-B-5)
3-6752) (2) Urea resin or melamine resin impregnation (3) Liquid phenol resin impregnation has been attempted, but there are advantages and disadvantages, and none satisfying basic requirements has been obtained. That is, (1)
Although the water resistance is improved by the method of, the strength is insufficient,
If the compounding amount of the thermosetting resin is increased to increase the strength, a welding phenomenon will occur.

In the impregnation method (2), the grindstone becomes too hard and cracks occur during aging. The impregnation of the phenol resin of (3) has many impregnation irregularities, and uniform impregnation is impossible.

An object of the present invention is to solve the above problems and to provide an impregnating liquid used for producing a grindstone excellent in water resistance and grindability as well as lapping property.

[0006]

The above object can be achieved by the following impregnating liquid for a porous grindstone.

(A) Phenol resin (b) Polyvinyl alcohol (c) Aldehyde (d) Acid catalyst
5 to 95 parts by weight relative to 100 parts by weight of polyvinyl alcohol, 20 to 80 parts by weight of aldehyde to 100 parts by weight of polyvinyl alcohol, and 5 to 10 parts by weight of acidic catalyst to 100 parts by weight of polyvinyl alcohol. Aqueous impregnating liquid.

Phenol resin 1 with polyvinyl alcohol
By using 5 parts by weight or more with respect to 00 parts by weight, it is possible to increase the affinity with the grindstone to be impregnated.
If it exceeds 5 parts by weight, the viscosity of the impregnating liquid becomes high and the permeability to the grindstone deteriorates.

The presence of the aldehyde and the acidic catalyst in the present invention can be effectively exerted by making the above specified amount relative to polyvinyl alcohol.

The above-mentioned aqueous impregnation liquid of the present invention is preferably
A porous grindstone using a resin having elasticity as a basic binder is impregnated and dried, and heated at a temperature of 40 to 130 ° C. to cause a formalization reaction and condensation of a phenol resin.
It is used for heat treatment at 0 to 200 ° C., whereby a porous bonding layer can be additionally formed on the impregnated porous grindstone to manufacture a porous grindstone using an elastic resin as a binder. .

[0011]

The preferred embodiment of the phenol resin in the present invention is a low molecular weight condensate of various phenols such as phenol, xylenol and cresol with an aldehyde and its derivative such as alkyd-modified resin epoxy-modified resin esterified with phthalic anhydride. It includes etherified phenol resin, melamine modified resin, phenol ether modified resin and the like. This phenol resin has a sufficiently low molecular weight and is used in the form of an aqueous solution or an emulsion, but depending on the application, a powdery phenol resin having a slightly higher molecular weight dissolved in a solvent such as alcohol can also be used. For the purpose of increasing the hardness of the grindstone, one having a high molecular weight or emulsion is used. In order to improve machinability, a mixture of low molecular weight and high molecular weight is used. In order to improve the wrapping property, one having a relatively low molecular weight is used.

[0012] PVA is preferably a completely saponified product, but a well-known one suitable as a binder for a grindstone that can be used even if some acetic acid groups remain is used. It is desirable that PVA has a molecular weight of 500 to 2000 and a saponification degree of 98% or more.

The weight ratio of the phenol resin to PVA is 5 to 95 parts, preferably 40 to 70 parts, of PVA to 100 parts of the phenol resin, and the hardness can be adjusted according to the intended use of the product. Further, other resins such as melamine resin, urea resin, epoxy resin, polyamide, synthetic rubber, polyvinyl butyral, polyvinylidene chloride and unsaturated polyester may be used together within the limit of 5% of the total amount of resin. A melamine resin, a urea resin or the like is used for the purpose of increasing the water resistance, and an epoxy resin, a melamine resin or the like is used for increasing the hardness.

The aldehyde may be any one having an aldehyde group, and examples thereof include formaldehyde, acetaldehyde, benzaldehyde, crotonaldehyde, furfural and the like.

The amount used may be an appropriate amount, but is usually PVA10.
It is about 20 to 80 parts, preferably 30 to 60 parts (weight ratio) with respect to 0 part.

As the acidic catalyst, inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, etc. as well as organic acids such as paratoluene sulfonic acid are used, and a sufficient and sufficient amount for the reaction is sufficient.
It may be about 5 to 10 parts (weight ratio) with respect to 00 parts.

The impregnating liquid having such a composition is preferably a uniform solution or emulsion, but may be a sol in which fine particles are dispersed. The amount of water contained in the impregnating liquid is preferably 65% by weight from the viewpoint of maintaining the porosity of the grindstone obtained by the production method of the present invention and improving the water resistance, and the permeability of the impregnating liquid (impregnating property). % Or more, usually 70% by weight or more. The viscosity of the impregnating liquid is usually 10 cps or less, and at most 20 to 30 cps or less. In order to maintain the stability of the emulsion or sol, a surfactant, a thickener, an anti-agglomeration agent, etc. may be used as long as they do not interfere.

The impregnating solution of the present invention is different from the impregnating solution containing only the phenol resin in that it has a good affinity for the grindstone and does not cause unevenness. As a result, the hardness and water resistance of the final product are uniform, and cracks do not occur during heating.

That is, the greatest effect of the impregnating solution of the present invention is that the affinity with the PVA bond grindstone is dramatically improved by simply combining the impregnating solution of the conventional phenol resin with PVA, aldehyde, and acid, and evenly and uniformly. This affinity is the reason why impregnation can be carried out and the reason why the water resistance, hardness and machinability of the final product are improved. Also, when a phenol resin is mixed in the binder and molded (for example, Japanese Patent Publication No. Sho 49-
3430, 53-6752), the reason why the lapping property is better is that the surface of the abrasive grains is coated with the phenol resin. If the grindstone is hydrophilic, PVA with high saponification degree (98% or more) is used, and if the grindstone is hydrophobic, PVA with low saponification degree (about 88%) is used. Increasing the amount of PVA with respect to the phenol resin increases the affinity with the grindstone, but if the amount is too large, the viscosity of the impregnating liquid increases and the permeability to the grindstone deteriorates. (Note that the types of aldehyde and acid are
(Almost does not affect the affinity with the grindstone)

The grindstone formed and solidified by a conventional method is impregnated with this impregnating solution.

As the resin-bonded porous grindstone, a PVA formalized product bonded or a PVA resin mixed with an initial condensate of a water-soluble thermosetting resin and subjected to a formalization reaction (so-called porosity) Bonded grindstone), other fine-grained resinoid grindstone, vitrified grindstone, porous epoxy, grindstone with urethane bond, etc. are used.

The grindstone is impregnated and then dried. First, the grindstone is subjected to a formalization reaction and a condensation reaction of a phenol resin at 40 to 40 ° C.
Heat treated at 130 ° C. After that, in addition to this, a heat treatment at 130 to 200 ° C. for several hours is performed to cure. By this two-step heat treatment, a uniform and even grindstone can be produced without causing cracks during heating. The finished grindstone has excellent water resistance, strength, machinability, and abrasion resistance, while maintaining the good lapping property that the porous bond grindstone originally has.

In addition to the above-mentioned porous grindstone, the impregnating liquid of the present invention can be applied to porous grindstones such as resinoid grindstones and vitrified grindstones, thereby improving the accuracy of the finished surface. .

The heating time depends on the shape of the grindstone, the proportion of PVA phenol resin, the temperature, etc.
The higher the proportion of the phenolic resin and the lower the treatment temperature, the longer the time required, but usually about 20 to 25 hours at 120 to 140 ° C and about 12 to 20 at 150 to 200 ° C.
It's about time. Generally, heat treatment at 180 ° C. for about 15 hours is desirable.

According to the present invention, a porous grindstone having appropriate hardness or machinability and lapping characteristics depending on the purpose is prepared according to the (phenol resin / PVA) compounding ratio of the impregnating liquid.
It can be obtained according to various polishing purposes and objects, and also has excellent water resistance.

Examples of the present invention will be described below.

[0027]

【Example】

(Example 1) A so-called porous bond grindstone (outer diameter 3
05 mm, central hole diameter 152.4 mm, thickness 25 mm) was manufactured by the following method.

With respect to 100 parts of a 20% aqueous solution of PVA,
Phenolic resin 50 parts, formalin 20 parts, GC # 10
After adding 60 parts of abrasive grains of No. 00 and stirring well, a formalization reaction was carried out at a temperature of 60 ° C. for 20 hours using hydrochloric acid as a catalyst,
A porous bond grindstone is obtained by washing with water and drying.

This porous bond grindstone was mixed with 25 parts by weight of a 20% aqueous solution of PVA (parts by weight, the same applies hereinafter), 50 parts of a water-soluble phenol resin, and 15 parts of formalin as a catalyst, and hydrochloric acid was used as a catalyst.
After treatment with an impregnating solution containing 0 parts, formalization at 50 ° C. and condensation of a phenol resin are performed, and then at 180 ° C. for 5
Heated for 10 hours. When a copper roll was polished with the grindstone obtained by the above treatment, there was no scratch and the wear resistance was good. PVA is Kuraray Poval 105 and water-soluble phenolic resin is TD-230 (manufactured by Dainippon Ink and Chemicals).
7 was used.

(Comparative Example 1) The same as the porous bond grindstone obtained in Example 1 (not impregnated).

Comparative Example 2 Using the same porous bond grindstone as in Example 1, a liquid phenol resin (resin content 60%) was used.
%) And 10 parts of 1% dilute hydrochloric acid were impregnated, dried and then heat-treated at 150 ° C. for 15 hours to obtain a grindstone. The result was that impregnation unevenness was remarkable and the ground surface was also defective.

[0032]

[Table 1] Grinding conditions 1) Grinding method Cylindrical plunge grinding 2) Grinding wheel size 305 × 25 × 152.
4 3) Workpiece S45 (raw material) 60φ x
50l 4) Grinding wheel grinding width 25 mm 5) Grinding liquid Water-soluble grinding liquid W ₂ 6) Grinding wheel peripheral speed 2000 m / min 7) Work rotation speed 20 m / min 8) Cutting speed 1.2 μ / rev 9) Spark out time 20 sec As a result of the same polishing test as in Example 1, the surface roughness was poor and scratches were also observed. Table 1 shows a comparison between Example 1 and Comparative Examples 1 and 2.

Example 2 A porous bond grindstone was obtained by the same method as in Example 1. This porous bond grindstone is PVA
Hydrochloric acid 1 as a catalyst in a mixed solution of 20 parts (weight part) of 20% aqueous solution, 60 parts of water-soluble phenolic resin, and 15 parts of formalin.
After treatment with the impregnating solution containing 0 parts, formalization and condensation of the phenol resin were carried out at 60 ° C, and then at 180 ° C for 5
Heated for ~ 10 hours. SUS30 using the obtained whetstone
When the round bar of No. 4 was ground, there was no scratch and a good quality surface was obtained.

The phenol resin / PVA ratio (weight ratio) is usually 1/10 to 10/1, but preferably 1/3 to 3
It is / 1.

(Example 3) The same porous bond grindstone as in Example 1 was used for 25 parts of 20% aqueous PVA solution, 30 parts of emulsion type liquid phenol resin (80% resin content) formalin 1
The mixture was treated with an impregnating solution obtained by adding 10 parts of hydrochloric acid as a catalyst to a mixed solution of 5 parts, followed by formalization at 50 ° C. and condensation of a phenol resin, and then heating at 170 ° C. for 5 to 8 hours. The obtained grindstone had no impregnation unevenness, and the inside of the grindstone was uniformly impregnated.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C08L 29:04) 6904-4J

Claims (1)

[Claims] 1. A phenol resin comprising: (a) a phenol resin, (b) polyvinyl alcohol, (c) an aldehyde, and (d) an acidic catalyst, wherein the polyvinyl alcohol is a phenol resin 100.
5 to 95 parts by weight relative to 100 parts by weight of polyvinyl alcohol, 20 to 80 parts by weight of aldehyde to 100 parts by weight of polyvinyl alcohol, and 5 to 10 parts by weight of acidic catalyst to 100 parts by weight of polyvinyl alcohol. Aqueous impregnating liquid.