JPS587647B2 - Hannobutsu o Renzokutekininoushiyuku Sasenagara Oshidastameno Souchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for continuously concentrating a resin having self-condensing properties, which is suitable for concentrating reaction resin products, and particularly suitable for producing molds or cores for shell molds.

It has already been proposed to use resol-type phenolic resins for molding materials or for coating refractory granules or, in particular, for coating molding sand grains.

In general, resol type phenolic resin refers to phenols 1
Using 1 mol or more of formaldehyde per mol,
A resin obtained by reacting these in the presence of an alkaline catalyst, and the resin is a resin obtained by using an alkali metal hydroxide as a catalyst, usually called a resol, and ammonia, a primary amine, or a secondary amine. It is broadly divided into resins called ammonia aresols, which are obtained using ammonia and the like as catalysts.

The resol is obtained as a viscous liquid, is water-soluble or hydrophilic, and is soluble in organic solvents such as alcohol and acetone, and is generally used as a face.

On the other hand, the ammonia aresol is characterized in that it can be obtained not only as a viscous liquid but also as a solid product depending on the conditions, and is hydrophobic and soluble in organic solvents such as alcohol and acetone.

Compared to liquid resols, solid resols as described above are particularly useful in that they are extremely easy to handle and have excellent storage stability.

However, solid ammonia aresol has the following significant difficulties in its production.

That is, since it has self-condensing properties, if a heating reaction is carried out until it becomes a solid state, condensation proceeds like a chain reaction, making it extremely difficult to control the reaction.

In addition, for mass production, the reaction container is generally 3000~I
A resin with a capacity of OOOOJ is used, but after heating the reaction to around 100℃, the resin of iooo~4000J is simultaneously rapidly cooled within a few minutes to a temperature at which the self-condensation reaction does not occur (approximately 30℃). This is almost impossible industrially.

In other words, resin materials generally have heat insulating properties, and it is impossible to cool the inside of the resin material using external cooling methods, and self-condensation progresses inside, causing an explosive exothermic reaction and hardening. .

As mentioned above, there are various difficulties involved in producing solid resols, but it has also been extremely difficult to obtain solid resols that do not contain water in order to ensure coating properties and storage stability of the resin.

In other words, even if an attempt is made to simply remove water from the reactants in a high-temperature atmosphere under normal pressure, the reaction of the resin will be further promoted by such a rise in temperature, resulting in a rapid decrease in the amount of methylol groups and the formation of coated granules. This is because the curing speed becomes slow and the caking strength inevitably deteriorates extremely.

Several methods for continuously producing phenolic resins that have been known for a long time are all for novolac type resins, and resol type resins having self-condensing properties have generally been manufactured in a batch system.

Although resol-type resins have recently been produced by spray-drying, this method involves spraying a certain reaction product of resol resin from the top of a tower, and is somewhat effective in removing water. However, it has the disadvantage that it is extremely difficult to adjust the temperature inside the spray drying tower in order to obtain a solid resol with an optimal softening point for applied products.

In other words, it is extremely difficult to control the reaction of atomized resin as it falls naturally due to the height of the tower.

The purpose of the present invention is to eliminate the various drawbacks inherent in the prior art as described above, and to make the present invention suitable for producing resins with desired properties, particularly solid resols having self-condensing properties, while carrying out quantitative continuous heating reactions. The objective is to provide a device with

In other words, the feature of the present invention is that instead of simultaneously proceeding the reaction of a large amount of resin product to a desired degree as described above, an amount of resin product that can be easily quenched per unit time is transferred. For example, the torque fluctuation of the screw shaft used to feed the product is detected and the feed rate is controlled based on the limit, so that the reaction progresses one after another and the reaction reaches the desired degree at the time of discharge. It is to be done.

This is because if the degree of reaction is insufficient, the desired softening point of the resin cannot be obtained, and if the degree of reaction is excessive, the product may gel and the function of the device itself may stop. be.

In addition, since the certain reaction product of the resol resin supplied to this device still contains about 15% water, it is necessary to evaporate and actively dehydrate it in parallel with the progress of the reaction, without disturbing the transfer order. The goal is to make the piston flow.

Furthermore, since the influence of negative pressure based on the above-mentioned active dehydration inhibits the extrusion of the resin, in order to prevent this, a compressing part of the resin is added by the variable pitch of the screw shaft at the end of the concentration process. be.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention shown in the drawings will be explained in detail below.

In the figure, 1 and 1' are installed horizontally in parallel, and one on the left and one
A pair of screw shafts that are engaged with each other with leads, and have sealed hollow inner holes 2, 2', and support shaft portions 3, 4, 3 at both ends.
', 4' are extended respectively.

Reference numeral 5 denotes a cylindrical body that seals the screw shafts 1, 1', and its inner wall has a portion 6 that fits only with the outer diameter of the terminal end of the screw shafts 1, 1', and the other portions are located above the outer diameter of the screw shafts. An exhaust chamber 7 is formed in the exhaust chamber 7.

In order to maintain the transfer level of the plastic material at the highest level, this exhaust chamber 7 is designed so that the upper edge 8 of the root diameter of the screw shafts 1, 1' is set at a lower limit level (the inner wall of the cylinder forming the exhaust chamber away from the outer diameter of the screw shaft). (lowest position).

9 and 91 are replacement screws that are fitted and connected to the support shaft portions 3 and 3', forming a further limited terminal portion of the screw shaft terminal portion that fits into the portion 6 of the cylinder body 5; Its thread pitch is set smaller than that of other parts.

Reference numerals 10 and 11 denote end walls which close both ends of the cylindrical body 50 and at the same time make sliding contact with the terminal end surfaces of the screw shafts 1, 1' and 9, 9', and engage downwardly at the terminal surfaces of the screw shafts 9, 9'. A discharge port passing through the side wall 10 is provided at a position opposite to the vicinity of the point 12, from which a discharge pipe 13 protrudes and extends.

14 is a sheath that covers the outer shell of the cylinder 5, and has independent chambers I, ■, ■, separated from each other by partition walls 15 in the longitudinal direction of the screw shafts 1 and 1'.
(1), V, and each of these chambers opens with an inlet 16 and an outlet 17 allowing controlled entry and exit of a heating medium, such as steam.

Reference numeral 18 denotes partition walls arranged in double rows for each independent chamber in order to guide the heating medium efficiently, and passages 19 are formed by alternately cutting out the joints with both partition walls 15. are doing.

Reference numerals 20 to 22 are all openings formed through the cylindrical body 5 forming the exhaust chamber 7, 20 is a pair of intake ports connected to a raw material supply pipe (not shown), and 21 is connected to a pressure reducing device (not shown). The intake port 22 is a viewing window.

23, 23'l are supported by rotary joints 24, 24', and extend through the support shaft portions 3, 3' of the screw shafts 1, 1' into the inner holes 2, 2', respectively. With a shaped heating tube,
Jet holes 25 for a heating medium, such as steam, are provided through the circumferential wall at appropriate locations, and a water suction pipe 26 having water suction nozzles 27, 27' at its tip for discharging condensed water is coaxially built therein.

In addition, 28 is a motorized transmission, 29 is a speed reducer, 30 is a gear box, 31 is a bearing that supports the support shafts 4 and 4' of the screw shafts 1 and 1', respectively, and 32 and 32' are the support shafts. 3,3'
33 is a condensed water discharge hole penetrated through the lower bottom of the jacket 14. 6 A certain reaction product of a plastic material such as a resol resin is concentrated by the apparatus of the present invention, and phenol is 1 mole of formaldehyde and 1 to 3 moles of formaldehyde at 70°C in the presence of a catalytic amount of ammonia or amines! Approximately 60. This is an almost transparent product obtained by allowing the addition reaction to occur for a minute, and then removing water from the reaction mixture under reduced pressure while being careful not to exceed 70°C.

The product is introduced through the inlet 20 either directly or via a storage vessel.

The introduction flow rate of the product per unit time is determined according to the rotational speed of the screw shafts 1, 1', which is determined based on the properties of the desired product, until the level of the product inside the cylinder exceeds the upper edge 8 of the root diameter of the screw shaft. controlled so that it does not occur.

The screw shafts 1, 1' are each operated in an outward direction at a slow speed, for example, about 20 to 70 revolutions per hour, with the main purpose of pumping the product under pressure.

The product introduced from the receiving port 20 is transferred between the screw shafts 1, 1' and the cylinder 5 in a state where they are separated by almost every pitch of the screw thread, while the product is transferred to the sheath 14 and the heating tubes 23, 23.
Heating is carried out by the heating medium supplied to the inlets 27, 27', and condensed water as the condensation progresses is actively removed by a pressure reducing device connected to the inlet ports 27, 27'.

The heating temperature is determined in each independent chamber I, ■, ■, divided by partition wall 15.
■, by the time the product reaches the end of the screw shaft where it comes into close contact with the part 6 of the cylinder 5, it is approximately 70°C.
The temperature is raised to ~105°C, and then the screw shafts 1, 1'
Due to the close contact between the cylinder 5 and the cylinder 5, the product leaves the area of influence of the pressure reducing device and passes into the conveying stage.

At this stage, the reaction heat of the product itself is high, so the heating tube 2
The screw shafts 1, 1' are formed solid so as to avoid the influence of auxiliary heating caused by the screws 3, 23'.

When the product, whose level has been reduced somewhat by the removal of condensation water, has moved to a more limited end portion of the screw shaft end, the temperature of the product reaches a critical temperature of about 110° C. to 120° C. When the reaction proceeds to the desired extent, it is further rapidly compressed by the variable pitch of the replacement screws 9, 9', and the level of product rises to completely fill the void between the screw threads.

One of the advantages of the present invention is that the end surfaces of the screw shafts 9, 9' are in sliding contact with the side wall 10, and no chamber is provided at that location for discharging the product. There is no fear of turbulence caused by the process, and therefore the aging order is not disrupted at all, and moreover, it is forcefully extruded through the discharge pipe 13 from the vicinity of the lower engagement point 12 of the screw shafts 1, 1', which corresponds to the extreme position of compression. It will be done.

The extruded product has a viscosity of approximately 1,000 to 1,200 centipoise, and is immediately introduced into water and pulled up, or rapidly cooled and solidified by any cooling means (not shown), such as receiving water on an endless conveying belt, to form a solid resol. Resin is obtained.

The time required for the entire concentration process is about 40 minutes, but the softening point of the resin depends on the rotational speed of the screw shafts 1, 1' by the continuously variable transmission 28 and the heating medium supplied to the jacket 14 and heating tubes 23, 23'. is precisely controlled by adjusting the

In the above embodiment, the case where two screw shafts 1 and 1' are meshed is explained, but depending on the production volume, a structure in which three or more screw shafts are meshed in parallel may be used. is also possible.

According to the apparatus of the present invention described in detail above, the following numerous effects can be achieved.

(1) Since the reaction temperature and reaction time can be controlled in any way while continuously concentrating the resin product quantitatively, it is possible to produce resin products that meet the required properties extremely easily. .

(2) The produced resin product is extremely homogeneous since it is discharged continuously without any disturbance in the order of introduction.

(3) Since vacuum dehydration is performed during the concentration step, water of condensation from the resin product can be effectively removed.

(4) A pump action is applied to the screw shaft so as to overcome the negative pressure in the cylinder, and the pump action is more efficient because the product is pushed out from near the lower meshing point of the screw shaft.

(5) Since the upper edge of the valley diameter of the screw shaft is set as the lower limit level of the suction chamber, during the concentration process, the production amount can be maintained at the highest level within a range that does not allow the product to return.

[Brief explanation of the drawing]

The drawings illustrate one preferred embodiment of the present invention, and FIG. 1 is a plan view of the main parts of the device of the present invention, and FIG. 2 is a cut along the line ■-W in FIG. 3. FIG. 3 is a cross-sectional view taken along line 2-11 in FIG. 2, and FIG. 4 is a cross-sectional view taken along line 2-w' in FIG. In these figures, 1 and 1' are screw shafts, 2 and 2' are inner holes of the screw shafts, 3, 3', 4, and 4' are support shaft parts, 5 is a cylinder body,
10 and 11 are end walls, 13 is a discharge pipe, 14 is a jacket, 15 is a partition wall, 16 is an inlet, 17 is an outlet, 20 is an intake port, 21 is an intake port, 20 to 22 are openings, 23 and 23' are heating tube, 2
4, 24' are rotating joints, 25 is a spout hole, 26 is a water suction pipe,
27, 27' are water absorption nozzles, 28 is a motorized transmission, 2
9 is a reducer, 30 is a gear box, 31 is a bearing, 32, 32'
is a bearing, and 33 is a discharge hole.

Claims (1)

[Claims] 1 at least two meshed together for pumping plastic material
The screw shaft is sealed, and the inner wall is tightly fitted only with the outer diameter of the terminal end of the screw shaft whose thread pitch is set smaller than that of other parts, and the other parts are outside the screw shaft. A cylindrical body which forms an exhaust chamber in the radial upper part and has a discharge port for the plastic material penetrated through the end side wall thereof at a position opposite to the vicinity of the lower engagement point of the screw shaft, and is connected to the exhaust chamber. a depressurizing device, which covers the outer shell of the cylindrical body, and an independent chamber partitioned in the longitudinal direction of the screw shaft, each of which is connected to a heating source, and extrudes the reaction product while continuously concentrating it. A resol-type phenolic resin manufacturing device characterized by: