JPWO2020054574A1 - Inspection method and inspection equipment - Google Patents

Abstract

Provided is an inspection technique capable of detecting excess moisture after a dehydration / drying step and before molding. A method for inspecting a crumb-shaped polymer, which comprises continuously supplying a polymerized, dehydrated and dried crumb-shaped polymer, and detecting a crumb containing excess water in the crumb-shaped polymer.

Description

The present invention is a technique for inspecting the presence or absence of water in a crumb-shaped polymer to be supplied and transferred.

As an example of the process for producing a crumb-shaped polymer, the process for producing a synthetic rubber such as butadiene rubber will be briefly described.

A butadiene solution, which is a raw material, is prepared, a catalyst is added, and the solution is polymerized to obtain a polymer solution (polymerization step). The obtained polymer solution is steamed to recover the crumb slurry polymer (solvent removal step). The polymer containing water is dehydrated by an extruder and dried with hot air or the like to form a dry crumb (dehydration / drying step). The crumb-shaped polymer is compressed and molded (molding process). Generally, grains having a particle size of about 3 to 10 mm produced in the process of manufacturing synthetic rubber are called crumbs.

The invention of the present application relates to a molding process. The molding process will be described in a little more detail.

A crumb-shaped or powdered semi-finished product is a press-molded product (usually called a bale, hereinafter referred to as a bale) having a straight hexahedron shape in a press molding machine (usually called a baler, hereinafter referred to as a baler). ) Is press-molded.

At that time, the crumb-shaped polymer is automatically weighed and adjusted to the specified weight range. It is molded into a bale within the specified weight range, the weight is checked, the rubber bale is covered with a thin film packaging bag such as polyethylene film, polystyrene film, etc., and multiple pieces are stored in a storage container such as a container and shipped to the user. NS.

The veil is melted or melted, vulcanized, and processed on the user side.

As described above, since water is always used in the synthetic rubber manufacturing process, the water is removed in the dehydration / drying step. However, in reality, the water that could not be completely removed in the dehydration / drying step remains. A veil containing excess water may cause a defect in appearance or a defect on the user side.

On the other hand, in the conventional general molding process, a bale containing excess water is detected by a visual inspection by an observer after the bale is molded and before being carried out. However, the observer cannot detect the excess water inside the veil. In addition, the burden on the observer is heavy.

In Patent Document 1, by using an infrared transmissive transparent plate having a smooth surface and irradiating the sample rubber with infrared rays through the transparent plate while pressing the rubber, the water content of the sample rubber can be reduced in a short time. A technique that can measure with high accuracy has been proposed.

Japanese Unexamined Patent Publication No. 2004-020192

According to the technique according to Patent Document 1, by measuring the water content of the sample rubber and confirming that it is equal to or less than a predetermined value, it can be inferred that the veil as a product does not contain excess water.

However, as a result of investigating the mechanism by which excess water remains, the inventor of the present application has found that whether or not excess water remains is not regular and difficult to predict, and the water content of the sample rubber is equal to or less than a predetermined value. On the grounds, it is difficult to conclude that the product veil does not contain excess water.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an inspection technique capable of detecting excess water after a dehydration / drying step and before molding.

The present invention that solves the above problems is an inspection method in which a polymerized, dehydrated and dried crumb-shaped polymer is continuously supplied, and crumbs containing excess water in the crumb-shaped polymer are detected.

By detecting the crumb containing excess water in the crumb shape before molding the bale, it is possible to detect the excess water contained inside the bale, which could not be detected conventionally.

In the above invention, preferably, the temperature of the crumb-shaped polymer is measured, and the crumb containing excess water is detected based on the temperature difference.

In the above invention, preferably, the temperature of each station is measured for the continuously supplied crumb-shaped polymer, the average temperature of a plurality of stations is obtained, and the crumb corresponding to the station having a temperature lower than the average temperature is obtained. Is detected.

In the above invention, preferably, a crumb corresponding to a station having a temperature difference of 9.5 ° C. or more from the average temperature is detected.

As a result, it is possible to detect a low temperature portion due to the effect of vaporization of excess water or the effect of the temperature not easily rising.

In the above invention, preferably, the average temperature of the polymer when the dehydrated and dried crumb-shaped polymer is supplied is 40 to 70 ° C.

As a result, the above-mentioned effect due to excess water is likely to become apparent.

In the above invention, preferably, the crumb containing excess water is in the form of a lump.

Crumbs containing excess water tend to clump. Further, if it is in the form of a lump, it is easy to detect the influence of vaporization or temperature rise.

In the above invention, preferably, the crumb containing excess water has a water content of 1% by mass or more.

The present invention, which solves the above problems, comprises a supply means for continuously supplying a polymer, dehydrated and dried crumb-shaped polymer, a temperature measuring means for measuring the temperature of the crumb-shaped polymer supplied from the supply means, and the above. It is an inspection device provided with a determination means for calculating a temperature difference from the average temperature using a temperature measuring means and detecting a crumb containing excess water based on the temperature difference.

In the above invention, the excess moisture inspection means is preferably a thermograph camera.

The present invention can detect excess moisture after the dehydration / drying step and before molding.

It is a system block diagram which concerns on one Embodiment of this invention. It is a verification test result which is the basis of the basic concept of this invention. This is a detection example according to an embodiment of the present invention.

~System configuration~

FIG. 1 is a system configuration diagram according to an embodiment of the present invention.

The system includes a continuous supply means, an excess moisture inspection means, a bale equivalent weight measuring means, a bale molding means, a carrying-out means, and a control means, and performs a series of operations.

The continuous supply means is, for example, a vibration feeder 1. The vibration feeder 1 continuously supplies the crumb-shaped polymer 2 that has undergone the dehydration / drying step 8 after the polymerization to the system.

The excess moisture inspection means is, for example, a thermograph camera 3. The thermograph camera 3 is provided on the vibration feeder 1 and detects excess moisture by detecting a temperature not rise due to a crumb that is insufficiently dried (details will be described later).

The bale-equivalent weight measuring means is, for example, a weighing device 6 having a hopper. The hopper is provided between the continuous supply means and the bale molding means. The hopper has an upper hopper and a lower hopper. The operation of the upper hopper and the lower hopper is controlled, and the weight of the crumb-shaped polymer accumulated in the hopper is weighed by the weighing device 6, thereby measuring the weight of the crumb-shaped polymer corresponding to the bale.

The bale molding means is, for example, a pressure molding machine (baler) 7. The amount of crumb-shaped polymer weighed by the bale-equivalent weight measuring means is supplied, pressure-molded, and becomes a bale.

The carrying-out means is, for example, a conveyor 14. A weight measuring device 15 is provided in the middle of the conveyor 14.

The control device 30 inputs excess moisture inspection information from the excess moisture inspection means 3 and bale weight information from the weight measuring device 15 to perform sorting control. That is, excess moisture was not detected, and the bale with a weight in the normal range was carried out as a genuine product 12 to the next step (packaging step) 9, and excess moisture was detected or / and a bale with a weight outside the regular range was removed. It is removed as a non-standard product 13 and sent to another process 10 (reprocessing).

The excess water is not a substantial defect and can be reused as a material by reprocessing the crumb-like polymer containing the excess water.

~ Basic concept of the present application ~
The present invention focuses on the temperature difference due to excess moisture. FIG. 2 shows the verification test results that form the basis of the basic concept of the present invention. The vertical axis of FIG. 2 is the water content (mass%) of the crumb, and the horizontal axis is the numerical value obtained from [(WP surface temperature) − (average temperature of the crumb)]. Here, the WP surface temperature is the measured temperature of the portion of the crumb that is assumed to contain excess water, and the crumb average temperature is the average temperature of a plurality of stations.

After the polymerization, the crumb-shaped polymer continuously supplied to the molding step through the dehydration / drying step has an average temperature of 40 to 70 ° C. More specifically, in the verification test conducted in winter, the average temperature of the crumb-shaped polymer was 48.8 ° C, whereas in the verification test conducted in summer, the average temperature of the crumb-shaped polymer was 60. It was 7 ° C.

The average outside air temperature in winter at the verification test site is around 6 ° C, and the average outside temperature in summer is around 26 ° C. The average temperature of the crumb-like polymer after the dehydration / drying process is affected by the outside air temperature.

In both summer and winter, the temperature of the crumb-shaped polymer varied from -20 ° C to + 15 ° C around the average value. The water content of the crumb-shaped polymer at this time was investigated.

From the results of FIG. 2, the following can be seen. The water content was extremely low in crumbs having a WP surface temperature near the average crumb temperature or higher than the average crumb temperature. On the other hand, crumbs having a WP surface temperature lower than the average temperature had a high water content. In particular, when the temperature difference between the WP surface temperature and the average crumb temperature was 9.5 ° C. or higher, the water content of the crumb was very high.

In addition, crumbs containing excess water tended to form lumps. The portion of the mass containing excess water was defined as WET POINT (WP). While the crumbs after the dehydration / drying process are relatively hot, the crumbs containing excess water take away the heat of the crumbs when the water vaporizes, or the temperature is less likely to rise due to the addition of excess water. It is presumed to be.

Similar trends were seen in summer and winter. In one example of the test, the crumb surface temperature was 48.8 ° C. and WP35.4 ° C. (the temperature difference between the crumb surface temperature and WP was 13.4 ° C.) in winter, and the crumb surface temperature was 60.7 ° C. and WP47. The temperature was 4 ° C. (the temperature difference between the crumb surface temperature and the WP was 13.3 ° C.).

From this result, the temperature of the crumb-shaped polymer can be measured to detect the crumb containing excess water, and in particular, by paying attention to the temperature difference, the WET POINT can be reliably detected regardless of the outside air temperature. I decided. In particular, the WET POINT of crumbs containing 1% by mass or more of excess water can be detected.

~ Detection of crumbs (WET POINT) containing excess water ~
WET POINT is detected based on the temperature difference. More specifically, the WET POINT can be detected by finding the average temperature of a plurality of stations of the crumb and setting the station portion having a temperature lower than the average temperature as the WET POINT.

By setting the station portion having a difference of 9.5 ° C. or more from the average temperature as WET POINT, WET POINT can be detected with higher accuracy.

The average temperature of the crumb can be determined by, for example, the following method.

FIG. 3 is an example of temperature measurement. The temperature measuring means is a thermograph camera. Imaging at 30 frames / second is possible. As the thermograph camera 3, for example, CPA-L25B manufactured by Chino Corporation can be used.

A thermograph camera captures and images a crumb, and measures the temperature of each pixel in an image range (dotted line in the figure) corresponding to a predetermined range (for example, 600 mm × 500 mm) in each image. The average temperature of the crumb can be obtained from the measured temperature of each pixel.

When determining the average temperature, the station is preferably 100 to 100,000, more preferably 1,000 to 100,000, and particularly preferably 10,000 to 100,000. WET POINT can be detected with high accuracy.

Further, the WET POINT is detected by extracting low-temperature pixels having a temperature lower than a predetermined value (for example, 9.5 ° C.) from the average temperature.

~ Estimating the mechanism of excess water generation ~
It is premised that crumbs with excess water are not generated by undergoing the dehydration / drying step. Nevertheless, in practice, crumbs with excess water are generated. The mechanism was considered.

Moisture is discharged to the outside in the dehydration / drying process. At that time, small pieces stick to the inner wall surface of the discharge part. The small pieces absorb a part of the water discharged to the outside.

There is a risk that small pieces containing water will peel off due to some kind of trigger and will be mixed into the crumbs supplied to the next process (molding process).

Therefore, it is very difficult to predict the occurrence of crumbs with excess water.

~ About crumb mass ~
It is presumed that the characteristics of crumbs are that they are sticky, easily stick to each other, and tend to form crumb lumps. It is presumed that WET POINT is generated by the mixing of crumb mass containing excess water.

On the other hand, when the excess water is present together, the influence of vaporization or the like is likely to become apparent, and the low temperature portion is easily detected (see FIG. 3).

Therefore, the present application is suitable for detecting WET POINT, but is not limited to crumb masses, and is also applicable to crumbs.

The general crumb particle size is 3 to 10 mm. In the present application, a particle size of 20 mm or more is referred to as a crumb mass.

~effect~
From the above, excess moisture can be detected after the dehydration / drying step and before bale molding. As a result, excess water inside the veil can also be detected.

Since excess water can be detected before bale molding, for example, there is a possibility that a crumb-like polymer containing excess water can be removed in a falling trajectory to a baler.

By the way, the crumb-shaped polymer has adhesiveness, and as a result of the particles easily sticking to each other, the particle size becomes non-uniform and the behavior is difficult to predict. A complex mechanism is required to remove excess water-containing crumb-like polymers in the fall trajectory to the baler. On the other hand, if the bale containing excess water is removed after bale molding, it can be easily and surely removed.

In the above, no configuration or process is required other than the thermograph camera and simple control. Excess water can be detected easily and reliably without adding a new configuration or a new process to the existing manufacturing process. It does not affect the quality of the product.

Further, by paying attention to the temperature difference, it can be reliably detected without depending on the outside air temperature.

~ Target crumb-shaped polymer ~
The crumb-like polymer to be bale is vulcanizable rubber, for example, natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber. (CR), Butyl rubber (IIR), Nitrile rubber (NBR), Ethylene-propylene rubber (EPM, EPDM), Chlorosulfonated polyethylene rubber (CSM), Acrylic rubber (ACM), Urethane rubber (U), Silicone rubber (VMQ) , PVMQ, FVMQ), fluororubber (FKM), vulcanized rubber (T) and the like. In particular, with respect to the present invention, application to butadiene rubber (BR) is optimal. Butadiene rubber was used in the verification test.

~summary~
The average temperature of the crumb-shaped polymer continuously supplied to the molding step through the dehydration / drying step is 40 to 70 ° C. For example, in the verification test conducted in winter, the average temperature was 48.8 ° C, whereas in the verification test conducted in summer, the average temperature was 60.7 ° C. The water content of the crumb-shaped polymer at this time was investigated. Very low moisture content near and above average crumbs. On the other hand, when the temperature of the crumbs was lower than the average, particularly when the temperature difference from the average temperature was 9.5 ° C. or more, the water content was remarkably high. As an example, when the temperature of the mass of the crumb containing excess water was measured, it was 35.4 ° C. in winter (temperature difference 13.4 ° C.) and 47.4 ° C. in summer (temperature difference 13.3 ° C.). From this result, by measuring the temperature of the crumb-shaped polymer and paying attention to the temperature difference, it is possible to reliably detect the crumb containing excess water regardless of the outside air temperature.

1 Vibration feeder 2 Rubber crumb 3 Thermograph camera 6 Weighing device with hopper 7 Baler (pressure molding machine)
8 Dehydration / drying process 9 Packaging process 10 Reprocessing process 11 Abnormality detection signal 12 Genuine product (product)
13 Non-standard product 14 Conveyor 15 Weight measuring device 30 Control device

Claims (9)

A polymerized, dehydrated and dried crumbly polymer is continuously supplied.
An inspection method comprising detecting a crumb containing excess water in the crumb-like polymer. The temperature of the crumb-shaped polymer was measured and
The inspection method according to claim 1, wherein a crumb containing excess water is detected based on a temperature difference. For the continuously supplied crumb-shaped polymer, measure the temperature at each station,
Find the average temperature of multiple stations
The inspection method according to claim 2, wherein a crumb corresponding to a measuring point having a temperature lower than the average temperature is detected. The inspection method according to claim 3, wherein a crumb corresponding to a measuring point having a temperature difference of 9.5 ° C. or more from the average temperature is detected. The inspection method according to any one of claims 1 to 4, wherein the average temperature of the polymer when the dehydrated and dried crumb-shaped polymer is supplied is 40 to 70 ° C. The inspection method according to any one of claims 1 to 5, wherein the crumb containing excess water is in the form of a lump. The inspection method according to any one of claims 1 to 6, wherein the crumb containing excess water has a water content of 1% by mass or more. A supply means for continuously supplying a polymerized, dehydrated and dried crumb-shaped polymer,
A temperature measuring means for measuring the temperature of the crumb-shaped polymer supplied from the feeding means, and a temperature measuring means.
A determination means for calculating a temperature difference from the average temperature using the temperature measuring means and detecting a crumb containing excess water based on the temperature difference.
An inspection device comprising. The inspection device according to claim 8, wherein the temperature measuring means is a thermograph camera.

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