JPS5932520B2 - How to remove adhesive hardened resin - Google Patents

Description

Detailed Description of the Invention The present invention involves adding a resin containing furan resin as a binder to refractory aggregate (silica sand, chromite sand), and further adding a curing catalyst to produce an organic carbonaceous material used for manufacturing casting molds. When hard sand is kneaded in a kneader and transported, resin in the sand and fine powder of refractory aggregate (hereinafter referred to as resin) adhere to the surfaces of the trough inner wall, scraper, conveyor belt, etc. The present invention relates to a method for removing a cured resin layer.

When organic self-hardened sand is continuously kneaded and supplied using a kneader, resin adheres to the inner wall of the trough and the surface of the scraper and hardens, forming a layer that reduces the kneading ability and prevents the curing reaction due to frictional heat. promote and shorten pot life,
Because it interferes with the molding work, the cured resin layer is removed using a chip hammer or the like before or after the work is started, but this cured resin layer is strong and requires a lot of effort.

Furthermore, when the sand is transported by a belt conveyor, the resin does not simply adhere to the belt surface, but if the belt is made of rubber, it tends to corrode the surface, making it extremely difficult to remove the cured resin layer. As a result, they gradually accumulate, deforming the belt and deteriorating its performance, significantly shortening its service life. An object of the present invention is to solve the above-mentioned problems and to easily remove hardened resin that adheres to a kneading machine, a conveyor belt, etc.

In order to achieve this object, the present invention removes the adhesive hardening resin as described above by dissolving and peeling it using a diluted organic solvent containing water added to one or both of furfuryl alcohol and tetrahydrofuran. This is to provide a way to do so. As the organic solvent, furfuryl alcohol (hereinafter referred to as FA) and tetrahydrofuran (hereinafter referred to as THF) shown in Table 1 can be used. It should be noted that these organic solvents have no effect at all when used in the form of undiluted solution, but are effective when used after being diluted with water. The present invention will be explained in detail below with reference to figures showing experimental results of the present invention.

The figure shows the three-component composition diagram of FA, THF, and water. The adhesion curing results were obtained from the following experiments using these stock solutions and solutions in which the mixing ratio of the two or three components was varied in 10% by weight increments. The resin removal rate is shown in %. In the same figure, the apex of the upper blade of the equilateral triangle represents FA stock solution (100%), the apex of the lower left blade represents the case of THF stock solution (100%), and the apex of the lower right blade represents the case of 100% water. For each edge, if the components of the vertex are zero (2 by the components at both ends of each edge)
component system), and the distance between these paired vertices and edges is 1.
The case where the composition is divided into 0 equal parts and the component at each vertex is changed by 10% by weight from 10 to 90% by weight is shown at the intersection of each equal dividing line in the equilateral triangle. In this experiment, 1,001 liters of each stock solution and mixed solution as described above were prepared in one beaker, and 1,000 ml of each of the above-mentioned stock solutions and mixed solutions were prepared in one beaker, and 300 ml of each of the above-mentioned stock solutions and mixed solutions were used for transporting organic self-hardened sand using a resin containing furan resin as a binder.
A belt with a cured resin with a thickness of W1 is
Place the cut pieces of 01I11 into each of the above liquids.
After soaking for 8 hours, the adhesive cured resin is peeled off, and the average removed thickness is % of the initial thickness of 31I111.
This is what I asked for.

As is clear from the figure, in the case of only water, F
In the case of the stock solution containing 100% A and THF, no dissolution and peeling effects are observed.

On the other hand, as shown on the right hypotenuse and bottom sides, the effect appears when water is added to the stock solution of FA or THF. F
In the case of A and water, it is effective when water is in the range of 10 to 80% by weight, and the effect is particularly large when water is in the range of 20 to 70% by weight.
The most effective case was when the water content was 50% by weight, with a removal rate of 41%. In the case of THF and water, even a small amount of water added had a large effect, with a removal rate of 55% when water was 10% by weight, and the highest removal rate was 56% when water was 20% by weight. . However, in the case of THF and water, the removal rate is 24 when the amount of water added is 50% by weight, and if water is added in an amount of 70% by weight or more, the effect is lost. Also, as shown on the left hypotenuse,
Although no effect is observed when the stock solutions of FA and THF are mixed together, as is clear from the numerical values inside the equilateral triangle, a greater effect appears when water is added to these mixed solutions. That is, when FA is 30% by weight, THFf)S5O is 20% by weight, a removal rate of 73% is obtained,
In the range of 20 to 40 wt% FA, 30 to 70 wt% THF, and 10 to 40 wt% water, the removal rate was 59%.
(f) A very high effect was obtained. In addition, the effects of the diluted solutions of FA, THF, and their mixtures mentioned above on the general structural rolled steel material SS-41, which is the material of the trough and scraper of the kneading machine, and the hardened comb, which is the material of the conveyor belt. When we investigated the effects, we obtained the results shown in Table 2.

In this experiment, SS-4 was added to the three dilution solutions shown in Table 2.
1 board and conveyor belt each weigh 30g? The pieces cut into corners were immersed for 10 days and the results were examined. An ○ mark indicates that there was no change. Example 1 After operating the kneading machine (10T0n/Hr) continuously for 8 hours, a lid was attached to the kneading sand outlet at the tip of the trough, approximately 70 kg of silica sand was added, and FA (30 parts by weight of 5THF and 7
To 100 parts by weight of silica sand, add 10 parts by weight, or 7 kg, of a diluted solution prepared by adding 50 parts by weight of water to a mixture of 0 parts by weight, and after rotating the scraper for 5 minutes, open the discharge port and take out the sand. As a result, it was found that the resin adhering to the inner wall of the trough and the scraper had been completely removed.

Example 2 A mop-type cleaning device was installed on a new belt conveyor, and the mop was cleaned after work while exuding a diluted solution mixed in the same proportion as in Example 1.
Even after several months of use, no resin deposits were observed on the belt surface.

As described above, according to the present invention, adhesion and hardening resin can be easily removed, especially if the resin layer is relatively thin and is removed by cleaning. By preventing the resin layer from accumulating over a long period of time, it is possible to prevent deterioration in the function and performance of related equipment such as a kneading machine and a conveyor belt.

[Brief explanation of the drawing]

The figure is a three-component composition diagram showing the results of an experiment of the present invention, and the numerical values on the equilateral triangle indicate the removal rate (%) of the adhered and cured resin.

Claims (1)

[Scope of Claims] 1. The surface of the trough inner wall of a kneading machine, scraper or belt conveyor by kneading organic self-hardened sand using a resin containing furan resin as a binder or by conveying the sand after kneading. A method for removing a cured resin, which comprises removing the cured resin by using a diluted organic solvent prepared by adding water to one or both of furfuryl alcohol and tetrahydrofuran. 2 The diluted organic solvent is added to furfuryl alcohol by 10 to 8
A method for removing adherent hardened resin according to claim 1, which comprises adding 0% by weight of water. 3. The method for removing adhered and cured resin according to claim 1, wherein the diluted organic solvent comprises tetrahydrofuran with 5 to 50% by weight of water added. 4 The diluted organic solvent consists of furfuryl alcohol, tetrahydrofuran and water, and the weight percent of these is 20
90, 10-95 and 5-70.