JPH0881615A - Resinoid wheel - Google Patents

Abstract

PURPOSE: To obtain a resinoid wheel useful for grinding, abrasion and cutting under high load, having improved hot flexing strength, normal-temperature flexing strength after a heat cycle test and excellent thermal shock resistance, containing grinding particles and a binder composed of a specific phenolic resin. CONSTITUTION: This resinoid wheel contains (A) grinding particles and (B) a binder composed of a resin prepared by co-condensing 1 naphthol or 2-naphthol and a phenol resin with an aldehyde. The resin of the component B is a resin obtained by co-condensing 100 pts.wt. of a phenol and 5-300 pts.wt., especially 10-50 pts.wt. of a naphthol with an aldehyde in an amount of 0.5-2.5mol based on 1mol of the phenol by using an acid catalyst or an alkali catalyst. A resin containing the naphthol in the ratio obtained by blending the phenol resin or the naphthol resin with the co-condensed resin may be used. Or a resin obtained by mixing the phenol resin with the naphthol resin and co-condensing the mixture in curing may be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resinoid grindstone, and more particularly to a grinding, polishing and cutting resinoid grindstone for high load applications where heat resistance and thermal shock resistance are required.

[0002]

2. Description of the Related Art Grinding high hardness materials such as cast iron under high load,
Abrasive and cutting resinoid grindstones are mainly made of alumina oxide having a relatively coarse grain size as abrasive grains, and generally a phenol resin is used as a binder, and are manufactured by heat molding from these. In recent years, resinoid grindstones have been required to have heat resistance and thermal shock resistance due to crack prevention and high grindability. Therefore,
As a binder, a modified phenol resin such as boric acid or a maleimide resin, or a maleimide resin has been tried. However, the resinoid grindstone using the modified phenolic resin as the binder improves the heat resistance, but the thermal shock resistance does not effectively improve, and the resinoid grindstone using the maleimide-based resin has a high curing temperature and Due to the poor adhesiveness with the particles, there is a drawback that the heat resistance is consequently lowered.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The present invention has been earnestly studied for resinoid grindstones having improved heat resistance and thermal shock resistance in high load applications, and as a result, 1-naphthol and / or 2-naphthol as a binder has been obtained. By using a resin in which aldehydes and phenols were co-condensed with aldehydes, we obtained the knowledge that the above characteristics were improved, and based on this knowledge, we proceeded with various researches and completed them.

[0004]

In the present invention, a resin obtained by co-condensing 1-naphthol and / or 2-naphthol and a phenol with an aldehyde is usually used in an amount of 5 to 100 parts by weight of a phenol. 300 parts by weight,
A resin obtained by co-condensing 10 to 50 parts by weight of naphthol and 0.5 to 2.5 mol of aldehyde with respect to phenols with an acid catalyst or an alkali catalyst is preferable. If the amount of naphthol is 5 parts by weight or less, the effect due to modification does not appear. When the amount is 300 parts by weight or more, the heat resistance and the thermal shock resistance are the same or slightly improved, but the adhesion to the base material is lowered. Further, it may be a resin in which a phenol resin or a naphthol resin and a co-condensation resin are mixed so that the ratio of naphthol is the above ratio, or a resin in which a phenol resin and a naphthol resin are mixed and co-condensed at the time of curing. included.

The phenols used in the present invention include phenol, orthocresol, metacresol,
It is at least one or more phenols selected from phenols such as para-cresol, xylenol, para-tertiary-butylphenol, para-octylphenol, para-phenylphenol, and bisphenol A. Phenols with less steric hindrance are preferable, but the limitation is not particularly limited. do not do. The aldehyde is formaldehyde, acetaldehyde, butyraldehyde, acrolein, or a mixture thereof, and it is also possible to use a substance which is a source of generation of these aldehydes or a solution of these aldehydes.

Examples of the alkali catalyst include alkali metal hydroxides such as lithium, sodium and potassium, alkaline earth metal hydroxides such as magnesium, calcium and barium, and salts such as carbonates having the same action and effect. Oxides can be used, and amines, ammonia, and other alkali catalysts can be used together. As the acid catalyst, organic acids such as oxalic acid, p-toluenesulfonic acid, xylenesulfonic acid and phenolsulfonic acid, and inorganic acids such as hydrochloric acid and sulfuric acid can be used. Hexamethylenetetramine, paraformaldehyde, trioxane and the like can be contained as a curing agent.

The abrasive grains used in the present invention include alumina oxide, silicon carbide, diamond and the like, but are not particularly limited. Other fillers that can be used include inorganic fillers such as cryolite, iron sulfide, iron oxide, barium sulfate, quicklime, and organic fillers such as thermosetting resin-cured powder, rice husk, and wood powder. Also, in order to improve the adhesiveness with the abrasive grains,
Treating the abrasive grain surface with a silane coupling agent, or furfural, furfuryl alcohol,
It is possible to pre-moisten it with creosote oil, other organic solvent, or phenol resin which is a liquid resin.

[0008]

[Function] Since the resinoid grindstone of the present invention is a co-condensation resin of naphthol and phenols, it has a high crosslinking density,
It has sufficient characteristics to retain abrasive grains, and its strength is extremely small due to the heat resistance of naphthol at high temperatures.

[0009]

EXAMPLES The present invention will be described in detail below with reference to examples. All "parts" and "%" described herein indicate "parts by weight" and "% by weight".

(Production Example 1) 800 parts of phenol, 200 parts of 2-naphthol, and 10 parts of oxalic acid were placed in a four-necked flask.
After the temperature of the mixture reaches 90 ° C., 575 parts of 37% formaldehyde is added thereto for 60 minutes to carry out an addition reaction. After refluxing for 120 minutes, a vacuum dehydration reaction is performed to form a solid phenol at room temperature. 2-naphthol polycondensate 850
I got a part. 100 parts of the obtained polycondensate of phenol and 2-naphthol and 14 parts of hexamethylenetetramine were pre-kneaded and pulverized to obtain powdered phenols.
-110 parts of naphthol co-condensation resin A were obtained.

(Production Example 2) In a four-necked flask, 600 parts of phenol and 400 parts of 2-naphthol were added, and then 10 parts of oxalic acid.
After the temperature of the mixture reaches 96 ° C., 530 parts of 37% formaldehyde is added thereto for 60 minutes to carry out a side-by-side reaction. After refluxing for 120 minutes, a vacuum dehydration reaction is carried out to conduct solid phenol reaction at room temperature. 2-naphthol polycondensate 830
I got a part. 100 parts of the obtained phenol-2-naphthol polycondensate and 14 parts of hexamethylenetetramine were pre-kneaded and pulverized to obtain 110 parts of powdery phenols and 2-naphthol co-condensation resin B.

(Production Example 3) 1000 parts of phenol, 650 parts of 37% formaldehyde, and then 1 part of oxalic acid were charged into a four-necked flask, and the temperature was gradually raised. After the temperature reached 96 ° C., the mixture was refluxed for 120 minutes. Then, the dehydration reaction was carried out under vacuum, and the container was removed from the kettle. 960 parts of a solid novolac type phenolic resin was obtained at room temperature. 14 parts of hexamine was premixed with 100 parts of the obtained novolac type phenol resin, and this was pulverized to obtain 110 parts of powdery phenol resin C.

(Production of Grindstone Test Piece) A grindstone test piece was prepared and subjected to a bending strength test. In addition, the compounding conditions of the grindstone test piece and the preparation procedure are as follows. Abrasive grains (A # 12): 100.0 parts Resin: 15.0 Iron sulfide: 10.0 Cryolite: 10.0 Quick lime: 1.5 Furfural: 1.0 Abrasive grains and furfural are mixed in a laboratory mixer at room temperature For 5 minutes, and then mixed powder of resin, iron sulfide, cryolite and quicklime is mixed and kneaded for 3 minutes. 15 × 2 of the above mixture
Put in a mold of 5 × 100mm, temperature 160 ℃, pressure 50
It was molded at 0 kg / cm ^{2 for} 15 minutes. From room temperature to 170 ℃ for 10 hours, then 170 ℃ for 5 hours, total 1
Firing was carried out for 5 hours to obtain a whetstone test piece having a whetstone bulk specific gravity of 3.05.

Example 1 A resinoid grindstone test piece was prepared in accordance with the above (Production of grindstone test piece) using a powdery phenol / 2-naphthol co-condensation resin A as a binder. << Example 2 >> Powdered phenols as a binder
Using the 2-naphthol co-condensation resin B, a resinoid grindstone test piece was prepared according to the above (Production of grindstone test piece). << Comparative Example 1 >> Phenolic resin C in powder form as a binder
Using the above, a resinoid grindstone test piece was prepared according to the above (manufacture of grindstone test piece).

With this test piece, at room temperature and hot (250
The bending strength at each temperature was measured and evaluated. Further, in air, a heat cycle test was performed in which exposure was repeated 10 times under a 300 ° C. atmosphere for 30 minutes and a 25 ° C. atmosphere for 30 minutes, and the bending strength was measured at room temperature. Table 1 shows the results.

Table 1 Bending strength ───────────────────────────────── Example 1 Example 2 Comparative example 1 ───────────────────────────────── Phenolic resin used A B C Normal temperature bending strength (kg / cm ² ) 436 425 443 Hot bending strength (kg / cm ² ) 248 245 221 bending strength after heat cycle test (kg / cm ² ) 83 121 41 41 ───────────────── ─────────────────

[0017]

EFFECTS OF THE INVENTION The resinoid grindstone of the present invention has improved hot bending strength and room temperature bending strength after a heat cycle test as shown by the above results, and is recognized to have excellent heat resistance and thermal shock resistance. To be

Claims (1)

[Claims] 1. A resinoid grindstone containing a binder and the like composed of abrasive grains and a resin composition, wherein the binder is a resin in which 1-naphthol and / or 2-naphthol and phenols are co-condensed with aldehydes. Resinoid grindstone characterized by that.