JP2021116366A - Pellet production method of crosslinked resin - Google Patents

Abstract

To provide a pellet production method which dispenses with a complicated work, and can appropriately make a resin material containing a crosslinked resin into a pellet having a predetermined length.SOLUTION: A pellet production method includes melt-kneading a resin material containing a crosslinked resin, extruding the obtained molten resin material from a discharge part 36 having a small hole of an extrusion device 30, and cutting a molten-resin material extruded by cutting means 40 arranged in the discharge part into a pellet-like object having a length of less than 6 mm before cooling and solidification. Preferably, the pellet-like object is blown by air blowing means and is introduced into an air-cooling device for cooling, and is cooled by air cooling.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing pellets of a crosslinked resin.

In general, synthetic resins such as polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), and polystyrene (PS) are used as the resin material constituting the resin molded product. After being discarded, the resin molded product composed of these resin materials may be appropriately collected and recycled as recycled pellets. Resin pellets containing recycled pellets are used as raw materials for molding resin molded products. In this type of resin pellet, the recovered resin molded product or the like is crushed, melt-kneaded by an extruder or the like, extruded into a long string shape, cooled in a water tank or the like in which cooling water or the like is stored, and then cooled. It is obtained by cutting into a predetermined size (see, for example, Patent Document 1).

For example, in resin molded products such as trays and packages that store fruits and vegetables such as fruits and vegetables, cross-linked polyethylene rolls that are highly protective and easily adapt to irregular shapes are used because the stored fruits and vegetables are easily damaged. It is preferably used as a resin material. Then, in the production of this kind of resin molded product, a large amount of scrap material is generated. Therefore, from the viewpoint of reducing the environmental load, it is required to recycle and effectively use these offcuts.

However, crosslinked resins such as crosslinked polyethylene and crosslinked polypropylene have a molecular structure in which polymer molecular chains are bonded in a three-dimensional network, so that when a molded product or the like is crushed and melt-kneaded, it is melted and crushed. Things tend to be difficult to bond with each other. Therefore, even if the molten resin material (molten resin material) is extruded from an extruder or the like, the molten resin material itself becomes brittle and cannot maintain the long string-like shape at the time of extrusion, so that it can be used in a water tank or the like. Immediately before cooling, it collapses due to its irregular shape and length. As described above, it is extremely difficult to pellet the crosslinked resin by the general pellet manufacturing method.

Further, as a method for treating the crosslinked resin, there is a method in which a supercritical fluid for chemically reacting with the crosslinked resin is mixed and pelletized (see, for example, Patent Document 2). In this treatment method, the crosslinked resin and the supercritical fluid are mixed under high temperature and high pressure using a supercritical fluid to destroy the crosslinked structure, and the obtained processed product is cooled and then cut and pelletized. NS. However, in the treatment method using a supercritical fluid, since high temperature and high pressure are the treatment conditions, not only the work process becomes complicated, but also high energy is required, which is disadvantageous in terms of cost and is also preferable in terms of environmental load. do not have.

As described above, the crosslinked resin has little practicality as a material for recycling. Therefore, waste containing crosslinked resin must be treated as industrial waste at a great cost. Therefore, there is a demand for a pellet manufacturing method capable of appropriately recycling waste containing crosslinked resins.

Japanese Unexamined Patent Publication No. 2011-140587 JP-A-2007-106827

The present invention has been made in view of the above points, and it is necessary to appropriately pelletize a resin material containing a crosslinked resin to a predetermined length without requiring complicated work and avoiding an increase in cost. It provides a method for producing pellets capable of producing pellets.

That is, in the invention of claim 1, the resin material containing the crosslinked resin is melt-kneaded, the obtained molten resin material is extruded from the small hole type discharge portion of the extruder, and the cutting means arranged in the discharge portion. The present invention relates to a method for producing a crosslinked resin pellet, which comprises cutting the molten resin material extruded by the above into pellets having a length of less than 6 mm before cooling and solidifying.

The invention of claim 2 relates to the method for producing pellets of a crosslinked resin according to claim 1, wherein the resin material contains 50% by weight or more of the crosslinked resin.

The invention of claim 3 relates to the method for producing pellets of a crosslinked resin according to claim 1 or 2, wherein the crosslinked resin is crosslinked polyethylene or crosslinked polypropylene.

The invention of claim 4 relates to the method for producing pellets of a crosslinked resin according to any one of claims 1 to 3, wherein the pellet is cooled by air cooling.

The invention of claim 5 relates to the method for producing pellets of a crosslinked resin according to claim 4, wherein the pellet is blown off by a blowing means and introduced into an air cooling device for cooling.

In the method for producing a pellet of a crosslinked resin according to the invention of claim 1, the resin material containing the crosslinked resin is melt-kneaded, and the obtained molten resin material is extruded from a small hole type discharge portion of an extruder, and the above-mentioned Since the molten resin material extruded by the cutting means arranged in the discharge portion is cut into pellets having a length of less than 6 mm before cooling and solidifying, complicated work is not required and an increase in cost can be avoided. It becomes possible to appropriately pelletize a resin material containing a crosslinked resin, which has been extremely difficult to pelletize, with a predetermined length.

The invention of claim 2 can contribute to the reduction of environmental load because the resin material contains 50% by weight or more of the crosslinked resin in claim 1.

The invention of claim 3 can be easily obtained as a recycled material because the crosslinked resin is crosslinked polyethylene or crosslinked polypropylene in claim 1 or 2.

In the invention of claim 4, since the pellet-like material is cooled by air cooling in claims 1 to 3, it can be cooled and solidified so as not to contain water during cooling.

According to the fourth aspect of the present invention, since the pellet-like material is blown off by the blowing means and introduced into the air-cooling device for cooling, the pellet-like material can be quickly and appropriately introduced into the air-cooling device. can.

It is the schematic of the manufacturing apparatus of the pellet containing the crosslinked resin. It is the schematic sectional drawing of the extruder. It is a schematic front view and the schematic sectional view which shows the structure of the discharge part of an extruder and a cutting member.

The present invention is a pellet manufacturing method for molding a resin pellet molded product from a resin material containing a crosslinked resin (hereinafter referred to as a crosslinked resin), and the resin material containing the crosslinked resin is melt-kneaded to obtain the same. The molten resin material is extruded from the small hole type discharge part of the extruder, and the molten resin material extruded by the cutting means arranged in the discharge part is cut into pellets having a length of less than 6 mm before cooling and solidifying. It will be.

The crosslinked resin is a resin having a molecular structure (crosslinked structure) in which polymer molecular chains are bonded in a three-dimensional network shape by subjecting a synthetic resin to a crosslinking treatment. The crosslinked resin contained in the resin material used in the pellet manufacturing method of the present invention is, for example, a discarded crosslinked resin molded product or a crosslinked resin waste such as scraps generated during the production of the crosslinked resin molded product. May contain a cross-linked resin other than the discarded cross-linked resin. Examples of the crosslinked resin include crosslinked polyethylene and crosslinked polypropylene. Cross-linked polyethylene and cross-linked polypropylene are materials often used for molded products made of cross-linked resin, and can be easily obtained as recycled materials.

Further, the resin material containing the crosslinked resin preferably contains 50% by weight or more of the crosslinked resin from the viewpoint of reducing the environmental load and the like. In particular, if the resin material is composed of only the crosslinked resin (100% by weight), it can greatly contribute to the reduction of the environmental load. If it is not composed only of crosslinked resin, non-crosslinked resin is added. When a non-crosslinked resin is added, for example, a non-crosslinked resin of the same type as the crosslinked resin is selected, such as non-crosslinked polyethylene for cross-linked polyethylene and non-crosslinked polypropylene for crosslinked polypropylene. By adding the non-crosslinked resin to the crosslinked resin, the resin material can be melt-kneaded more appropriately and the shape retention of the resin material is improved.

Here, a preferred embodiment of the method for producing pellets of the crosslinked resin will be specifically described together with the pellet manufacturing apparatus 10 shown in FIG. The pellet manufacturing apparatus 10 includes a crushing means 20, an extrusion device 30, a cutting means 40, a blowing means 50, and a cooling means 60. In the pellet manufacturing method of the embodiment, a crushing step, a melt kneading step, an extrusion cutting step, and a cooling step are performed by using the pellet manufacturing apparatus 10. In FIG. 1, reference numeral 70 is a storage portion for the molded pellet-like material.

The crushing step is a step of crushing and stirring the raw material which is the source of the resin material for molding the pellet molded product, and is performed by the crushing means 20. As the crushing means 20, for example, a crushing device such as a known mixer is preferably used. Examples of the raw material include a discarded resin molded product, resin waste such as scraps generated during the production of the resin molded product, and an appropriate material such as a resin pellet as a raw material for the molded product. These raw materials are supplied as a crosslinked resin material alone, or a crosslinked resin material and a non-crosslinked resin material are supplied at a predetermined blending ratio, depending on the blending ratio of the target crosslinked resin. The crushed raw material is transported to the extrusion device 30 described later by a transport means 21 such as a known conveyor as a resin material for molding the pellet molded product.

This crushing step is an indispensable process especially when recycling a resin molded product or the like. At the time of recycling, it is necessary to melt the resin molded product or the like once, but if the molded product or the like has a large lump in the same shape or the like, it becomes difficult to melt it properly. Therefore, by pulverizing the molded product or the like to an appropriate size, the resin material can be easily melted appropriately. The size of the crushed product (resin material) such as the molded product is appropriate depending on the performance of the crushing means 20, for example, about 2 to 5 mm.

The melt-kneading step is a step of melting a resin material obtained by crushing in a crushing step and kneading to obtain a molten resin material, which is performed by an extruder 30. As the extrusion device 30, a known device can be preferably used. For example, as shown in FIG. 2, the resin material input from the main body 31 into which the resin material is introduced and the transport means 21 of the crushing means 20 32, such as a hopper, and a heating unit 33, such as a heater, which heats and melts the resin material in the main body 31, and the introduced resin material is transferred to the tip side while being kneaded. A screw 34 for obtaining the molten resin material, a driving means 35 such as a motor for driving the screw 34, and one or a plurality of small hole type discharge portions 36 for discharging the molten resin material obtained by melt kneading. And have.

In the extruder 30 of the embodiment, the discharge portion 36 is composed of an opening having a small diameter of about 2 to 6 mm. As shown in FIGS. 2 and 3, it is preferable that a plurality of the discharge portions 36 are formed in terms of production efficiency. In the embodiment, the plurality of discharge units 36 are arranged in a circle on the tip surface of the extruder 30 as shown in FIG. 3A, for example.

In the melt-kneading step, first, the resin material crushed from the transport means 21 of the crushing means 20 is charged into the charging section 32 and introduced into the main body 31 of the extrusion device 30. Then, the resin material introduced into the main body 31 of the extruder 30 is heated and melted by the heating unit 33 at a temperature sufficiently meltable corresponding to its melting point, and is melted by the rotation of the screw 34. The resin material is kneaded to obtain a molten resin material. The melting temperature of the resin material is appropriate depending on the type of the resin material, but for example, it is preferably set to be about 30 to 80 ° C. higher than the melting point of the resin material. If the set melting temperature is too low, it may not be sufficiently melted, and if it is too high, there is no change in the melting effect, which is economically disadvantageous. Further, the molten resin material is transferred to the tip side of the extruder 30 while being kneaded by the rotation of the screw 34. At that time, if necessary, the main body 31 may be provided with a degassing means such as a vacuum device to remove (degas) the air in the molten resin material. Degassing improves the shape retention of the molten resin material.

As described above, the melt-kneading step is carried out in the same treatment step as the melt-kneading treatment of a general resin material even if the resin material contains a crosslinked resin. Therefore, no special treatment for recycling the crosslinked resin is required, and complicated work and cost increase for that purpose can be avoided.

The extrusion cutting step is a step of cutting the molten resin material extruded from the discharge portion 36 of the extrusion device 30 before cooling and solidifying to obtain a pellet-like product having a length of less than 6 mm, and the extrusion cutting step is performed on the discharge portion 36 of the extrusion device 30. This is done by the arranged cutting means 40. As shown in FIG. 3, the cutting means 40 includes a cutting blade 41 and a rotating means 42 for rotating the cutting blade 41. In the cutting means 40 of the embodiment, as shown in FIG. 3A, the rotating means 42 is provided at the substantially central portion of the plurality of discharging portions 36 arranged in a circle on the tip surface of the extruder 30, and the cutting blade 41 is provided. Is extended from the rotating means 42 in the direction of the discharge portion 36 so as to be arranged close to the discharge portion 36.

In the extrusion cutting step, the molten resin material extruded from the discharge unit 36 at an appropriate extrusion speed according to the rotation speed of the screw 24 of the extrusion device 30 is rotated at a predetermined rotation speed by the cutting blade 41 of the cutting means 40. It is cut to form pellets with a length of less than 6 mm. If the length of the pellet-like material is 6 mm or more, problems such as difficulty in maintaining the shape of the pellet-like material due to the characteristics of the crosslinked resin occur. The length of the pellet-like material is set by adjusting the extrusion speed of the molten resin material from the discharge portion 36 and the rotation speed of the cutting blade 41. The extrusion speed of the molten resin and the rotation speed of the cutting blade 41 are determined according to the performance and size of the extrusion device 30 and the cutting means 40. For example, the extrusion speed is 200 to 400 rpm and the rotation speed. Is about 150 to 450 rpm.

Further, in particular, since the cutting blade 41 is arranged close to the discharge portion 36, the molten resin material is cut immediately after being extruded. That is, the molten resin material is cut in a high temperature state (a temperature equal to or higher than the melting point of the resin material) before cooling and solidifying, particularly at the time of extrusion. The temperature of the molten resin material at the time of extrusion is substantially the same as the set temperature at the time of melt kneading (a temperature about 30 to 80 ° C. higher than the melting point of the resin material). In the high temperature state before cooling and solidification, the resin material containing the crosslinked resin is relatively easy to maintain its shape, and pellets having a predetermined length can be easily formed. That is, in the past, it was not possible to retain the shape of the molten resin material containing the crosslinked resin before cutting it to a predetermined length, and pelletization itself was impossible, but in the present invention, the shape is cooled. By cutting the molten resin material before it could not be held, it became possible to obtain pellets of a predetermined length. When the molten resin material is extruded from a plurality of discharge portions 36 and cut, if the obtained pellet-like material is too long (for example, 6 mm or more), the pellet-like material tends to stick to each other and a defective product occurs. There is a risk of problems such as

The cooling step is a step of cooling and solidifying the pellet-like product obtained by cutting by the cutting means 40 to obtain a pellet molded product, which is performed by the cooling means 60. As the cooling means 60, a known air cooling device or the like capable of cooling by air cooling is preferably used. Further, the pellet-like material obtained by being cut by the cutting means 40 can be transferred to the cooling means 60 by an appropriate method, but the pellet-like material is blown off by the blowing means 50 to cool the cooling means (air cooling device). It is preferable to introduce it to 60.

The blower means 50 is a device that applies compressed air to the pellets immediately after being cut by the cutting means 40 to blow them away and introduces them into the cooling means (air cooling device) 60, and is used by a known blower such as an air compressor. Be done. Since the pellet-like material obtained by being cut by the cutting means 40 has a relatively small shape having a length of less than 6 mm, it can be easily blown off by the compressed air of the blowing means 50. Further, when the pellets are continuously cut, the pellets may come into contact with each other. At that time, since the pellets immediately after cutting are softened at a high temperature, the pellets in contact with each other may adhere to each other. However, by applying the compressed air of the blower means 50 to the pellets in contact with each other, the adhered pellets can be separated from each other and appropriately blown off. By blowing the compressed air of the blower means 50 against the cut pellets in this way, the pellets can be quickly and appropriately introduced into the cooling means (air cooling device) 60. Reference numeral 51 is a transfer path for communicating the cutting means 40 and the cooling means 60 and transferring the pellet-like material blown off by the blowing means 50 to the cooling means 60.

In the cooling step, since the pellets are cooled by air cooling, the pellets do not come into contact with cooling water or the like during cooling unlike the conventional water cooling. When the pellet is cooled by water cooling, it may be cooled and solidified in a state of containing water. If the cooled and solidified pellet molded product contains water, problems such as bursting may occur when the pellet molded product is used as a raw material for a resin molded product and molded. Therefore, by cooling the pellet-shaped material by air cooling, it is possible to obtain a pellet molded product that has been cooled and solidified so as not to contain water during cooling.

Further, in the cooling step, the pellet-like material may be cooled while vibrating the inside of the air cooling device, if necessary. It is possible to prevent the pellets from adhering to each other during cooling due to the vibration in the air cooling device, and the pellets in the air cooling device can be agitated and cooled efficiently. The cooled and solidified pellet molded product is transferred to and stored in the storage unit 70 by an appropriate method such as blowing by a blowing device such as an air compressor, suction by a suction device, or transporting by a transport device such as a conveyor.

[Mixing ratio of pellet molded product]
The resin material is blended based on the blending ratio (% by weight) of Prototype Examples 1 to 10 described later, and the resin material is introduced into the extruder. Melt-kneaded at a set temperature of 190 ° C., the obtained molten resin material was extruded from the discharge part, cut by the rotary blade of the cutting means arranged close to the discharge part, and the obtained pellet-like material was blown off by the blower means. After being transferred to an air cooling device, it was cooled and solidified by air cooling at a set temperature of about 7 ° C. to produce a pellet molded product. In the extrusion device, 16 discharge portions having a diameter of 5 mm are arranged in a circular shape, and the extrusion speed of the molten resin material is set to 300 rpm. Further, as the cutting means, the rotation speed of the rotary blade was set to 400 rpm.

[Prototype example 1]
The blending ratio of the resin material of Prototype Example 1 was 60% by weight of cross-linked polyethylene (PE) and 40% by weight of non-crosslinked polyethylene.

[Prototype example 2]
The blending ratio of the resin material of Prototype Example 2 was 70% by weight of cross-linked polyethylene (PE) and 30% by weight of non-crosslinked polyethylene.

[Prototype example 3]
The blending ratio of the resin material of Prototype Example 3 was 80% by weight of cross-linked polyethylene (PE) and 20% by weight of non-cross-linked polyethylene.

[Prototype example 4]
The blending ratio of the resin material of Prototype Example 4 was 90% by weight of cross-linked polyethylene (PE) and 10% by weight of non-crosslinked polyethylene.

[Prototype Example 5]
The blending ratio of the resin material of Prototype Example 5 was cross-linked polyethylene (PE) alone (100% by weight).

[Prototype example 6]
The blending ratio of the resin material of Prototype Example 6 was 60% by weight of crosslinked polypropylene (PP) and 40% by weight of non-crosslinked polypropylene.

[Prototype example 7]
The blending ratio of the resin material of Prototype Example 7 was 70% by weight of crosslinked polypropylene (PP) and 30% by weight of non-crosslinked polypropylene.

[Prototype Example 8]
The blending ratio of the resin material of Prototype Example 8 was 80% by weight of crosslinked polypropylene (PP) and 20% by weight of non-crosslinked polypropylene.

[Prototype example 9]
The blending ratio of the resin material of Prototype Example 9 was 90% by weight of crosslinked polypropylene (PP) and 10% by weight of non-crosslinked polypropylene.

[Prototype Example 10]
The blending ratio of the resin material of Prototype Example 10 was crosslinked polypropylene (PP) alone (100% by weight).

[evaluation]
Regarding Prototype Examples 1 to 10, during the production of pellet molded products in terms of the type and blending ratio (% by weight) of the crosslinked resin, adhesion of pellets after cutting, transfer of pellets by blowing means (blow-off), pellets The shape retention of the molded product was evaluated. In the adhesion between pellets after cutting, "○" when the pellets are separated from each other when transferred by a blowing means, "△" when some pellets are adhered to each other, many When the pellets of the above were adhered to each other, they were marked with "x". In the transfer (blow-off) of pellets by means of ventilation, "○" if the pellets can be transferred properly, "△" if some of the adhered pellets cannot be transferred, When many pellets cannot be transferred (do not blow off), they are marked with "x". Regarding the shape retention of the pellet molded body, "○" when a pellet molded body of an appropriate size can be molded, "△" when a part becomes larger or loses its shape due to adhesion, and most of them become larger due to adhesion. When it became or lost its shape, it was marked as "x". And, as a comprehensive evaluation, for each item of adhesion, transfer, and shape retention, if all are "○", there is "○", and if there is even one "△" and there is no "×", there is "△", one. However, if there was an "x", it was evaluated as an "x". The results are shown in Table 1.

As can be seen from Table 1, good results were obtained in all of Prototype Examples 1 to 10. In particular, the results were also good in Prototype Examples 5 and 10 composed of the crosslinked resin alone (100% by weight). Since it is well known that the stability of the resin material and the molded product is improved as the non-crosslinked resin is added to the crosslinked resin, the blending ratio of the crosslinked resin can be arbitrary. Therefore, in consideration of reducing the environmental load, it was found that the blending ratio of the crosslinked resin is preferably 50% or more.

[Length of pellet molded product]
Based on the procedure of the pellet manufacturing method, a resin material blended with 60% by weight of cross-linked polyethylene and 40% by weight of non-cross-linked polyethylene is used, and the rotation speed of the rotary blade of the cutting means is as shown in Prototype Examples 11 to 17 described later. The length of the pellet-like material to be cut was adjusted by changing the above to obtain a pellet-molded product.

[Prototype Example 11]
Prototype Example 11 is a pellet molded product formed with a cutting blade rotation speed of 400 rpm and a length of about 1 mm.

[Prototype example 12]
Prototype Example 12 is a pellet molded product formed with a cutting blade rotation speed of 350 rpm and a length of about 2 mm.

[Prototype example 13]
Prototype 13 is a pellet molded product formed with a cutting blade rotation speed of 300 rpm and a length of about 3 mm.

[Prototype Example 14]
Prototype 14 is a pellet molded product formed with a cutting blade rotation speed of 250 rpm and a length of about 4 mm.

[Prototype Example 15]
Prototype Example 15 is a pellet molded product formed with a cutting blade rotation speed of 200 rpm and a length of about 5 mm.

[Prototype Example 16]
Prototype Example 16 is a pellet molded product formed with a cutting blade rotation speed of 150 rpm and a length of about 6 mm.

[Prototype example 17]
Prototype Example 17 is a pellet molded product formed with a cutting blade rotation speed of 100 rpm and a length of about 7 mm.

[evaluation]
Regarding Prototype Examples 11 to 17, during the production of the pellet molded product, the adhesion between the pellet-shaped products after cutting, the transfer (blow-off) of the pellet-shaped products by the blowing means, and the shape retention of the pellet molded product were evaluated. In the adhesion between pellets after cutting, "○" when the pellets are separated from each other when transferred by a blowing means, "△" when some pellets are adhered to each other, many When the pellets of the above were adhered to each other, they were marked with "x". In the transfer (blow-off) of pellets by means of ventilation, "○" if the pellets can be transferred properly, "△" if some of the adhered pellets cannot be transferred, When many pellets cannot be transferred (do not blow off), they are marked with "x". Regarding the shape retention of the pellet molded body, "○" when a pellet molded body of an appropriate size can be molded, "△" when a part becomes larger or loses its shape due to adhesion, and most of them become larger due to adhesion. When it became or lost its shape, it was marked as "x". And, as a comprehensive evaluation, for each item of adhesion, transfer, and shape retention, if all are "○", there is "○", and if there is even one "△" and there is no "×", there is "△", one. However, if there was an "x", it was evaluated as an "x". The results are shown in Table 2.

As can be understood from Table 2, good results were obtained in all of the prototype examples 11 to 15 (the length of the pellet molded product was about 1 to 5 mm). Further, in Prototype Example 16 in which the length of the pellet molded product was about 6 mm, adhesion between the pellet-shaped products was observed in a part, and the adhered state was maintained without separation, and a small amount of defective products were generated. .. On the other hand, in Prototype Example 17 in which the length of the pellet molded product was about 7 mm, many defective pellets were adhered to each other and the cut pellets were out of shape, and a large amount of defective products were generated.

From the results shown in Table 2, it was found that it is extremely difficult to obtain a pellet molded product having a desired length when the length for cutting the molten resin material is 7 mm or more. Further, when the cutting length was about 6 mm, a small amount of defective products were generated, but many good products were obtained. Considering the balance between molding accuracy and cost, it is considered that the length of the pellet-like material to be cut is preferably less than 6 mm.

As illustrated and described above, in the method for producing a pellet of a crosslinked resin of the present invention, a molten resin material containing the crosslinked resin is extruded from a small hole type ejection portion of an extruder, and the molten resin is extruded by a cutting means arranged in the ejection portion. Since the material is cut into pellets having a length of less than 6 mm before cooling and solidifying, the molten resin material can be cut to obtain pellets having a predetermined length before the shape cannot be maintained. Therefore, it becomes possible to appropriately pelletize a resin material containing a crosslinked resin, which has been extremely difficult to pelletize in the past, with a predetermined length. In addition, complicated work is not required during melt kneading of the resin material containing the crosslinked resin, and an increase in cost can be avoided, and a pellet molded product can be manufactured with workability and cost comparable to those of a general pellet manufacturing method. ..

As described above, in the method for producing pellets of a crosslinked resin of the present invention, a resin material containing a crosslinked resin is appropriately cut by cutting a molten resin material containing the crosslinked resin into pellets having a length of less than 6 mm before cooling and solidifying. It can be pelletized. Therefore, waste containing crosslinked resin, which could not be pelletized and treated as industrial waste, can be used as a recycled material, which can be expected to contribute to reduction of environmental load.

10 Pellet manufacturing equipment 20 Crushing means 21 Transporting means 30 Extruding device 31 Main body 32 Input part 33 Heating part 34 Screw 35 Driving means 36 Discharging part 40 Cutting means 41 Cutting blade 42 Rotating means 50 Blower means 51 Transfer path 60 Cooling means 70 Reservoir

Claims (5)

The resin material containing the crosslinked resin is melt-kneaded, the obtained molten resin material is extruded from the small hole type discharge portion of the extruder, and the molten resin material extruded by the cutting means arranged in the discharge portion is used. A method for producing pellets of a crosslinked resin, which comprises cutting into pellets having a length of less than 6 mm before cooling and solidifying. The method for producing pellets of a crosslinked resin according to claim 1, wherein the resin material contains 50% by weight or more of the crosslinked resin. The method for producing pellets of a crosslinked resin according to claim 1 or 2, wherein the crosslinked resin is crosslinked polyethylene or crosslinked polypropylene. The method for producing pellets of a crosslinked resin according to any one of claims 1 to 3, wherein the pellets are cooled by air cooling. The method for producing crosslinked resin pellets according to claim 4, wherein the pellets are blown off by a blowing means and introduced into an air cooling device for cooling.

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