JPS6023768B2 - Solid resol resin manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solid resol type phenol formaldehyde resin (hereinafter simply referred to as solid resol) used as a binder in a shell mold casting method.

). Conventionally, in the shell mold casting method, 10 to 15% by weight of hexamethylenetetramine (hereinafter simply referred to as hexamine) is used as a novolac resin and a curing agent for the novolac resin.

) have been widely used as binders. This binder, ie, a mixture of borac resin and hexamine, has a fast curing speed and is suitable for mass production line operations. However, on the other hand, hexamine is thermally decomposed during heating and generates harmful odor gases such as ammonia and formaldehyde, which is considered as an industrial pollution.

In addition, it is said that the harmful odor gas is a cause of casting defects such as pinholes. As a solution to these shortcomings, research has been conducted in the industry to develop substitutes for hexamine, and as a result, the use of curing agents for the novolac resins such as resol resins catalyzed by paraformaldehyde or alkali metal hydroxides. Alternatives have been offered, but none have achieved widespread use due to their inherent drawbacks. On the other hand, resol resins have attracted attention recently because they are self-curing and do not require a hardening agent, i.e., hexamine, and are not associated with the above-mentioned industrial pollution problem of generation of harmful odor gas or casting defects. In addition, the amount used in this industry is also increasing.

Compared to solid resols, liquid resol resins are more troublesome to handle due to their properties, and while solid resols can be stored for 6 months, solid resol resins cannot be stored for more than 3 months. Attention is being paid to the development of However, during the production of solid resols, since resol resin has self-curing properties, in the B stage, that is, it solidifies at room temperature, and the solidified resol resin is subjected to a condensation reaction under heating until it can be plasticized by heating again. The condensation reaction progresses rapidly, reaching the C stage, that is, a three-dimensional silk-like structure, after several minutes or tens of minutes, making it extremely difficult to control the reaction, especially when mass-producing. Have difficulty. Generally, in the case of resol resin, the end point of the condensation reaction carried out in the reaction vessel is 100
Up to now, only a few methods have been provided to obtain a solid resol resin by quenching within a few minutes without causing a gelation phenomenon. Among these methods, there is a method in which the material is discharged into water and cooled and solidified, but in this method, the condensation reaction is carried out in a reaction vessel up to the B stage, and then the material is transferred all at once to a separately provided water tank. Therefore, it solidifies into large blocks in the aquarium. During this solidification process, the resol resin is gradually cooled and solidified from the outside, but this internal part that forms the separate core is difficult to cool and solidify, and may end up turning into a gel, making it unsuitable for practical use. be. Therefore, an object of the present invention is to provide a solid resol manufacturing apparatus that can smoothly and reliably cool and solidify the entire resin.

The gist of this invention is to discover that a solid resol in the form of a rod can be rapidly produced by arranging a solid resol producing apparatus consisting of this chamber at the bottom of the reaction vessel.

To give an overview of the device of this invention, this device consists of two chambers, upper and lower.The upper chamber is for temporarily storing the Hashisol resin, and the lower chamber is for solidifying the Hashisol resin. The end face is open and is always submerged in a water tank located below this lower chamber, and the upper part has a pressure reducing means, so when the device is not in use, the entire volume of this lower chamber is a hollow part. It has become.

Furthermore, when the device is used, that is, when the pressure is reduced, water is sucked up from the lower tank, and the device is formed of two tanks: a water column tank and a pressure reduction tank. A partition plate is provided at the boundary between the upper chamber and the lower chamber. This partition plate is provided with a large number of through holes, and furthermore, a large number of sprayers are provided in the lower part of the partition plate to spray cooling water. Therefore, the resol resin taken out from the reaction vessel is guided to the upper chamber via the valve, and then quickly transported to the reduced pressure tank in the lower chamber by the weight of the resol resin and the reduced pressure provided in the lower chamber through the through hole of the partition plate. Move to. During this time, the surface portion of the resol resin is solidified by the cooling water sprayed from the spray. Further, the solidified resol resin on the surface falls into the water column tank due to its own weight, and is completely solidified inside in this water column. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to describe the apparatus of the present invention in detail, a description will be given below with reference to a first diagram showing one embodiment of the apparatus of the present invention.

A is a reaction container, and inside this container, resol resin b that has undergone condensation reaction up to the B stage is stored, a steam layer c is provided around the outer wall, and a vacuum pump (not shown) is provided at the top. A passage d leading to is arranged. When operating the device of the present invention, first, with valve 1 closed, a vacuum pump (not shown) connected by conduit 2 is operated, and upper chamber 3 and decompression tank 4 are brought into a vacuum or near-vacuum state. Reduce pressure to At this time, the water 21 stored in the water tank 20' disposed at the lower part of the device of the present invention is transferred to the lower end opening 5 of the lower chamber.
It rises through the water column tank 7 and stops at a predetermined position 6 in the lower chamber.
form. After reducing the pressure, when valve 1 is opened, the resol resin passes through the upper chamber due to its own weight and the effect of reducing pressure.
It is led to the reduced pressure tank via a through hole 9 provided in the partition plate 8. At this time, a steam layer 10 is provided on the outer wall of the upper chamber 3 to prevent rapid cooling of the resin, and cooling water is sprayed from the spray 11 to solidify the surface of the resol resin. The resol resin led to the reduced pressure tank further falls due to its own weight and transfers to the water column tank, where it gradually falls. When falling in this water column tank, the resol resin requires residence time to reach from the upper surface 6 to the lower end surface 6 of the water column tank, but during this time it is completely solidified and the original shape of the solid resol is obtained. In addition, when performing the above-mentioned operation, it is preferable to supply pressurized air or a pressurized inert gas such as carbon dioxide gas or nitrogen gas from the upper part of the reaction vessel through conduit A in order to improve the flow of the resol resin. It's good to send it. Further, the water sprayed from the water tank 20
This is done by using the water 21 inside the tank and circulating it through the conduit 13 by the pump 12. At this time, when using in the summer, it is preferable to use the cooler B to improve the efficiency of water cooling. Next, the first
Since the structure of the partition plate 8 is not clear in the explanation shown in the drawings, the explanation will be made with reference to the second drawing, which is a partially enlarged view of one embodiment seen from the direction of the arrow in the decompression tank part shown in the first drawing.

In the second diagram, 14 is a partially enlarged plane of the partition plate 8, and 11
A through hole 9 provided in the partition plate 8 is a spray nozzle, and is formed by a string hole 16 located on the side of the reaction vessel for the Hizol resin and a wide hole 17 located on the side of the reduced pressure tank. 18 is a cooling water passage.

The 1,1' cross section of FIG. 2 is shown in the third illustration, and the third
FIG. 4 is an enlarged view of the portion marked 0 in the figure. 19 in Figure 4
is a weir member. As mentioned above, the recovery device for the resol resin formed into a rod shape through the through hole 9 of the apparatus of the present invention, completely solidified through the water column tank 7, and discharged from the lower end face 5 of the water column tank may be a combination of known processes. One example of this will be explained with reference to the first diagram. Solid resol taken out from the apparatus of the present invention is conveyed by an endless belt h of a belt conveyor g, and further transferred onto a belt conveyor i. This belt conveyor passes through a drying chamber j, and moisture is removed within this drying chamber. Thereafter, it is cut into a predetermined shape using a cutter k and placed in a container. m indicates the finished solid resol product. The numbers used to explain each figure here are added to explain the embodiments, and although the capital letters are not necessarily necessary as part of the inventive device, it is more preferable to provide this element. It was added because it is expected to be effective. Lowercase letters are added to explain publicly known parts. As mentioned above, by using the apparatus of the present invention, a solid resol can be obtained continuously and rapidly.

Furthermore, compared to conventionally provided devices, the present invention provides an industrially effective solid resol manufacturing device that is free from problems such as gelation, which have been considered difficult in the past.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the process for manufacturing a solid resol including the apparatus of the present invention, the second figure is a partially enlarged plan view of the partition plate on the reduced pressure tank side, which is a part of the apparatus of the present invention, and the third figure is a partial enlarged plan view of the partition plate on the reduced pressure tank side. is a sectional view taken along lines 1 and 1' in FIG. 2, and FIG. 4 is an enlarged sectional view taken at part 0 in FIG. Figure 2 Figure 3 Figure 4 Rudder

Claims (1)

[Claims] 1. In a solid resol resin manufacturing apparatus, below a resol resin reaction container, there is a resol resin solidification device consisting of an upper chamber and a lower chamber, and a water tank, and a boundary between the upper chamber and the lower chamber. includes a cooling water jetting means, a cooling water passage, and
A partition plate having a through hole forming a passage for the resol resin is disposed, and the lower chamber has an open lower end surface immersed in water and a pressure reducing means on the upper part, so that water is pumped from the water tank into the lower chamber when the pressure is reduced. A solid resol resin production device characterized by sucking up water into a water column tank and a decompression tank.