JPH01153275A - Elastic resin bond grinding stone and manufacture thereof - Google Patents

Abstract

PURPOSE:To enhance mechanical strength, bonding strength of bond and abrasive grains and wear and abrasion resistance keeping elasticity by using elastic resin bond as binder made of specific copolymer mainly. CONSTITUTION:Olefinic vinyl alcoholic copolymer is dissolved in mixed solvent comprising water and alcohol. In the next step, abrasive grains, aldehyde and filler are mixed in this copolymer solution and stirred. This mixture is added by acid, heated and reacted for a given time and acetalized. The resulting solid is rinsed, dried and then applied heat treatment. Thus, a desired elastic resin bond grinding stone is obtained. The grinding stone manufactured in such way is suitable for grinding a cemented carbide or ceramic workpiece or precision grinding in particular.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin bonded grindstone, particularly an elastic resin bonded grindstone, and a method for manufacturing the same.

[Prior Art and Problems] The elastic resin bond grindstone uses polyvinyl alcohol (PVA) as a binder (resin bond). A so-called PVA grindstone is common (for example, Japanese Patent Publication No. 53-6752). However, although this PVA whetstone has excellent elasticity, it does not have the strength originally required as a whetstone characteristic.
The wear resistance was insufficient.

An object of the present invention is to provide an elastic resin-bonded grindstone that can improve mechanical properties while maintaining excellent elasticity, thereby exhibiting excellent polishing properties. Another object of the present invention is to provide a method for manufacturing the elastic resin bonded grindstone.

C Solution] In order to solve this problem, the present inventors have conducted extensive research and found that they have used an olefin-vinyl alcohol copolymer as a binder and utilized this copolymer in the form of a water-alcohol solution. discovered that a new elastic grinding wheel with extremely excellent elasticity and mechanical properties could be obtained as a grinding wheel.
This completes the present invention. That is, one aspect of the present invention is as follows.

First invention: An elastic resin-bonded grindstone characterized by containing a binder mainly composed of an olefin-vinyl alcohol copolymer.

Second Invention An elastic resin-bonded grindstone characterized by containing a binder mainly composed of a niolefin-vinyl alcohol copolymer and blended with a thermosetting resin.

Third Invention A method for producing an elastic resin-bonded grindstone, which uses a binder mainly composed of a niolefin-vinyl alcohol copolymer and mixes the copolymer with other grindstone components in a water-alcohol solution state. .

Olefin-vinyl alcohol copolymer (rOV)
A resin) is a copolymer of olefin and vinyl alcohol, and is a type of thermoplastic resin.

This OVA resin is made of water, alcohol, and acetone.

They are insoluble in various solvents such as toluene.

Therefore, the reality is that it is hardly used for purposes other than injection molding. In particular, even when considered as a grinding wheel component (bond), it has the disadvantage that it is unsuitable for wet polishing due to its hygroscopic nature.

The present inventor prepared various solvents to make the OVA resin usable in a solution state, and found that it was soluble in a water-alcohol solvent. And this OV
It has been discovered that by further mixing a thermosetting resin with a solution prepared by dissolving resin A in a water-alcohol solvent, a grindstone having excellent mechanical properties and water resistance can be obtained.

9. In this specification, "other grindstone components" refer to grindstone components other than OVA resin, and include abrasive grains, binders (excluding OVA resin), and fillers.

[Preferred embodiments and effects] Olefins that are elements of OVA resin, that is, alkenes C
As a hydrocarbon of nH2n (n≧2).

It may be straight chain or branched, but preferably has 2 to 12 carbon atoms, more preferably 4 to 8 carbon atoms. The molar ratio of olefin to vinyl alcohol is preferably 30° to 70° to 30°, more preferably 4°.
It is 0:60 to 80:40.

A binder mainly composed of OVA resin means that the OVA resin accounts for 20 νt% or more based on the total amount of the binder. Preferably it is 50vt% or more.

Regarding the water-alcohol mixture as a solvent for dissolving OVA resin, the mixing ratio of water and alcohol and the type of alcohol are important for its solubility. The mixing ratio is 40-80ml of water and 50ml of alcohol.
~75m℃ (molar ratio 2:3~4:5) is preferred, water 6
More preferably, 40 to 30 ml of alcohol to 0 to 70 ml (molar ratio 3/4 to 5/4).

Note that the molar ratio of 2 is for methanol. As for the type of alcohol, those having 1 to 4 carbon atoms are preferred, and methanol, isopropyl alcohol, and n-propyl alcohol are particularly optimal. If the molten carbon content is low, it will be difficult to mix uniformly with other grinding wheel components, resulting in poor polishing properties. Once the OVA resin is dissolved, it will not gel even if the water-alcohol mixing ratio changes somewhat.

By using OVA resin in combination with other resins, bonding properties can be further improved. When one or more thermosetting resins, such as phenol resins, melamine resins, and urea resins, are used in combination, the water resistance of the grindstone can be improved. These may be used as an initial condensate, and an initial condensate of a phenol resin is particularly preferred. The mixing ratio of OVA resin and thermosetting resin ranges from 2:10 to 1O:1 (w
t%). Particularly preferred is a range of 3-near to 6;4. Moreover, when a PVA resin is used in combination, the pore forming property can be improved. The PVA resin may be a modified PVA resin. The mixing ratio with OVA resin is 0.5; 9
．． 5-1.5: range (wt%) of 7.5, especially 1;
9-1.5: It is preferable to appropriately select from the range of 7.5. When mixed, PVA resin may also be used in a solution state. When an aqueous solution of PVA resin is mixed, the PVA resin can be uniformly mixed to about 15 wt% with respect to the OVA resin (if it exceeds 15%, it will gel). The aqueous solution is preferably a PVA resin of 10 to 15 vt%. PVA
When the resin is dissolved in a water-alcohol mixture and mixed into the OVA resin solution as in the OVA resin, P
The VA resin can be uniformly mixed with the OVA resin in an amount of about 40vt%. Incidentally, since these thermosetting resins and PVA resins themselves also have a bonding function, they also improve the bonding force of the grindstone.

By acetalizing the OVA resin to form an acetalized product, it is possible to improve the bonding property with the abrasive grains and to generate pores. The degree of acetalization is preferably about 30 to 50%. For this acetalization, aldehydes and acid catalysts are used. Examples of the aldehyde include formaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, and crotonaldehyde.

Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, and boric acid, and organic acids such as balatoluic acid.

In addition, pores are generated by the acetalization reaction of OVA resin (and PVA resin), but a foaming agent such as Na
Porosity may be adjusted by using P 2 O, NaCf. Also, starch.

Dextrin etc. may also be used.

As for the abrasive grains, there are two common ones, such as silicon carbide.

Examples include normal abrasive grains such as alumina, and superabrasive grains such as diamond.

The production of the whetstone may be carried out, for example, by the following procedure. That is,
Dissolve OVA resin in a water-alcohol mixed solvent; add abrasive grains to this OVA resin solution.

Fillers such as aldehyde and other resins and foaming agents are mixed (in a solution state if necessary) and mixed with stirring; acid is added to this mixture and reacted at 40-80°C for 10-20 hours to form an OVA. Acetalizing the resin: The obtained solid is washed with water, dried, and then heat-treated at a temperature of 150 to 200°C for 5 to 15 hours.

The elastic resin bonded grindstone according to the present invention is made of carbide.

Suitable for grinding ceramic work materials, especially precision grinding.

[Example code] The present invention will be explained in detail below.

Example 1 0VA resin (olefin:vinyl alcohol-2:3 in molar ratio) was dissolved in a mixture of water and isopropyl alcohol (water:alcohol-3=2 in molar ratio), and 20
vt% OVA resin solution. This OvA resin solution 5
(1st year middle school: GC (#3000) 13.5kg, 3
7% formalin 2.5j7. Five water-soluble phenolic resins are added and stirred thoroughly, and a solution containing 400 g of potato starch is added and stirred again.

Then, 500 mA of 30% hydrochloric acid was added and mixed,
React at 60°C for 16 hours. The solid material thus obtained was washed with water, dried, and heat-treated at 170° C. for 8 hours to obtain a grindstone.

Example 2 A 10% PVA solution 21 (water:ethyl alcohol=6:4 was used as the solvent) was added to the same OVA resin solution 51 as in Example 1 and stirred.

Next, water-soluble phenolic resin (solid content 70%) 3i),
GC (#400) 6 kg, 37% formalin 1.5 (added and stirred, and then 30% hydrochloric acid 600
Add mA, mix, and react at 60°C for 16 hours. The solid thus obtained was washed with water and dried at 150°C.
A grindstone was obtained by heat treatment for 12 hours.

Example 3 0VA resin (olefin:vinyl alcohol-6:4 in molar ratio) was dissolved in a mixture of water and n-propyl alcohol (water:alcohol-4:6 in molar ratio), and 20
Prepare wt% OVA resin solution. , :(7) OVA resin solution 341:C (#220) 4 kg, 37% formalin 1p, liquid phenol resin (solid content 70%)
5 (added and stirred, then 100 m J of 35% hydrochloric acid
1 and reacted at 60° C. for 16 hours. The solid material thus obtained was washed with water and dried.

A grindstone was obtained by heat treatment at 150° C. for 8 hours.

Test Example Grinding tests were conducted on the grindstones obtained in Examples 1 to 3 above under the conditions shown in Table 1.

(Left below) According to the test results, the grindstones according to Examples 1 to 3 had particularly low grindstone wear compared to conventional PVA grindstones, a high grinding ratio, and a self-growth effect of the abrasive grains. There are also enough
Therefore, it had excellent grindability. In particular, even in the case of glass polishing (Example 2), no grinding burn occurred.

[Effects of the Invention] As described above, according to the present invention, while having elasticity, mechanical strength is high, the binding force between the bond and the abrasive grains is high, and the wear resistance is excellent. Furthermore, it also has a suitable self-growth effect of abrasive grains, and the phenomenon of seizure of the grindstone is stably suppressed over a long period of time. This is considered to be due to the presence of olefins in the OVA resin.

Therefore, the grindstone of the present invention is extremely useful in various types of grinding.

Furthermore, water resistance is improved by uniformly dispersing thermosetting resin, and porosity can be easily controlled by acetalizing the OVA resin itself, and furthermore, by acetalizing the PVA resin. extremely wide,
The industrial value is very high.

Claims (3)

[Claims] (1) An elastic resin-bonded grindstone characterized by containing a binder mainly composed of an olefin-vinyl alcohol copolymer. (2) An elastic resin-bonded grindstone characterized by containing a binder mainly composed of an olefin-vinyl alcohol copolymer and blended with a thermosetting resin. (3) A method for producing an elastic resin-bonded grindstone, which uses a binder mainly composed of an olefin-vinyl alcohol copolymer and mixes the copolymer with other grindstone components in a water-alcohol solution state. .