CN113085050B

CN113085050B - TPU particle production system and TPU particle without plasticizer

Info

Publication number: CN113085050B
Application number: CN202110342545.0A
Authority: CN
Inventors: 张国荣
Original assignee: Zhejiang Rock New Material Co ltd
Current assignee: Zhejiang Rock New Material Co ltd
Priority date: 2021-03-30
Filing date: 2021-03-30
Publication date: 2023-02-28
Anticipated expiration: 2041-03-30
Also published as: CN113085050A

Abstract

The invention provides a TPU particle production system which comprises three twin-screw extruders arranged in sequence and three cooling tanks arranged behind the extrusion end of each twin-screw extruder, wherein each cooling tank comprises a water cooling tank and a mounting plate for intersecting the water cooling tank into a first tank section and a second tank section, the mounting plate is provided with a through hole for communicating the first tank section with the second tank section, the mounting plate is also obliquely provided with a beveling knife for cutting an extruded material passing from the first tank section to the second tank section, and the extruded material is cut into a column shape with two inclined surfaces at two ends. The method provided by the invention has the advantages that the co-melting extrusion is carried out by three double-screw extruders, and the extrudate is cut into the column shape with the two end faces being inclined planes after each co-melting extrusion, so that the method is more efficient in drying the TPU particles, and the quality stability of the TPU particles is ensured. Also provided are TPU particle processing methods using the system and plasticizer-free TPU particles processed by the methods.

Description

TPU particle production system and TPU particle without plasticizer

Technical Field

The invention relates to the technical field of TPU (thermoplastic polyurethane) particles and processing thereof, in particular to a TPU particle production system, a TPU particle processing method and TPU particles without plasticizer.

Background

The TPU is thermoplastic polyurethane elastomer rubber which has high modulus, high strength, high elongation and high elasticity, and has excellent wear resistance, oil resistance, low temperature resistance and aging resistance. The rubber is mainly divided into polyester type and polyether type, has the advantages of wear resistance, oil resistance, transparency and good elasticity, and can be widely applied in various fields.

However, in the prior art, a single twin-screw extruder is generally used for single co-melting extrusion in the processing process, so that a plasticizer must be added when processing TPU particles, and finally, the TPU particles with stable quality can be obtained, otherwise, the processed TPU particles have the problem that moisture is not easy to remove.

However, the addition of the plasticizer reduces the environmental safety of the TPU particles, and the use of TPU particles containing the plasticizer causes a series of environmental problems, which limit the application of TPU particles in higher-end product fields.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a TPU particle production system suitable for TPU particles without plasticizer, which solves the problem that when a single twin-screw extruder in the prior art is used for processing, the plasticizer needs to be added, and the processing efficiency is reduced due to the adoption of multiple combined use.

According to the embodiment of the invention, the TPU particle production system comprises three twin-screw extruders which are sequentially arranged, and three cooling tanks which are arranged behind the extrusion end of each twin-screw extruder, wherein each cooling tank comprises a water cooling tank and a mounting plate for transversely cutting the water cooling tank into a first tank section and a second tank section, the mounting plate is provided with a through hole for communicating the first tank section with the second tank section, the mounting plate is also obliquely provided with a beveling knife for cutting an extruded material which passes through the second tank section from the first tank section, and the extruded material is cut into a column shape with two end faces both being inclined planes.

Furthermore, an ultrasonic generator and an ultrasonic receiver are fixedly mounted at two ends of the water cooling tank respectively.

Furthermore, the upper end surface of the mounting plate is positioned above the water cooling tank, and an air cylinder for driving the beveling knife to stretch is fixedly connected to the mounting plate;

the mounting plate is provided with a channel for the inclined cutter to enter and exit, the piston of the cylinder is fixedly connected with a connecting rod, and one end of the connecting rod, which is far away from the piston, is fixedly connected with the inclined cutter.

Furthermore, a guide cylinder for inserting the piston is fixedly connected to a side wall of the mounting plate close to the first groove section, and the connecting rod reciprocates between the guide cylinder and the channel when the cylinder operates.

Further, the bottom of the perforation is semi-circular, and the beveling knife includes a cutting edge that is the same shape as the semi-circular shape.

There is also provided, in accordance with an embodiment of the present invention, a plasticizer-free TPU particle processed with the above system, which is plasticizer-free and has a pillar shape with two inclined surfaces, wherein the pillar shape has a height of 4 to 5mm.

Compared with the prior art, the invention has the following beneficial effects:

the TPU particles are subjected to eutectic extrusion by three twin-screw extruders, and the extrudate is cut into a column shape with two inclined surfaces after eutectic extrusion every time, so that the TPU particles can be dried more efficiently, the quality stability of the TPU particles is ensured, and meanwhile, the processed TPU particles do not contain a plasticizer, and can be better applied to the field of higher-end products;

specifically, the moisture content of the TPU particles can be controlled to be below 0.05%, and meanwhile, the appearance of the obtained TPU particles is less affected by drying, so that the TPU particles can be more conveniently applied to processing.

Drawings

FIG. 1 is a first schematic view showing the structure of a cooling bath according to example 1 of the present invention (a cross cutter cuts through the perforations);

FIG. 2 is a second schematic structural view of a cooling bath according to example 1 of the present invention (the beveling knife does not block the through-holes);

FIG. 3 is a schematic view showing a coupling structure of a skew cutting blade and a coupling rod according to embodiment 1 of the present invention;

fig. 4 is a schematic side view (right) of the mounting plate of embodiment 1 of the present invention;

FIG. 5 is a schematic view showing the positional relationship between the ultrasonic generator and the ultrasonic receiver and the water-cooling tank in example 1 of the present invention;

in the above drawings:

the device comprises a water cooling tank 1, a first tank section 2, a second tank section 3, a mounting plate 4, a perforation 5, a beveling knife 6, an extrudate 7, a column 8, a cylinder 9, a connecting rod 10, a piston 11, a knife edge 12, a guide cylinder 13, an ultrasonic generator 14 and an ultrasonic receiver 15.

Detailed Description

The technical solution of the present invention is further illustrated by the following examples.

Example 1

As shown in fig. 1 to 5, the present embodiment provides a production system for processing the above TPU particles without plasticizer, which includes three twin-screw extruders arranged in sequence, and three cooling tanks disposed behind the extrusion end of each twin-screw extruder, wherein the materials are extruded by the twin-screw extruders and enter the corresponding cooling tanks for water-cooling and strip-drawing, and then are cut off, each cooling tank includes a water-cooling tank 1 and a mounting plate 4 for intersecting the water-cooling tank 1 into a first tank section 2 and a second tank section 3, the mounting plate 4 is provided with a through hole 5 for communicating the first tank section 2 with the second tank section 3, and the mounting plate 4 is further provided with a beveled cutter 6 for cutting off an extrudate 7 passing from the first tank section 2 to the second tank section 3; wherein, the two ends of the water cooling tank 1 are respectively and fixedly provided with an ultrasonic generator 14 and an ultrasonic receiver 15, namely, the ultrasonic generator 14 and the ultrasonic receiver 15 are respectively arranged at the inlet end and the outlet end of the extrudate 7.

As shown in fig. 1 and 2, the water in the water-cooling tank 1 is flowing water, and flows into the second tank section 3 from the first tank section 2 through the through hole 5, the water flow square is consistent with the moving direction of the extrudate 7, namely, the extrudate 7 enters the first tank section 2 after being extruded from the twin-screw extruder, then enters the through hole 5, is cut off by the beveling knife 6 in the through hole 5, and then enters the second tank section 3 along with the water flow; specifically, the water surface in the water cooling tank 1 is located at the upper position of the middle section of the through hole 5, and the extrudate 7 is located below the water surface, so that cooling is performed normally, and after cutting, a column 8 (i.e., the column 8 in the following examples and comparative examples) with two inclined end surfaces is formed, floats on the water surface, is collected, is drained, and is dried.

As shown in fig. 1 and 2, the upper end surface of the mounting plate 4 is located above the water-cooling tank 1, and the mounting plate 4 is fixedly connected with a cylinder 9 for driving the inclined cutter 6 to extend and retract;

the mounting plate 4 is provided with a channel for accommodating and withdrawing the inclined cutter 6, a piston 11 of the cylinder 9 is fixedly connected with a connecting rod 10, and one end of the connecting rod 10, far away from the piston 11, is fixedly connected with the inclined cutter 6. The cylinder 9 drives the connecting rod 10 and then drives the inclined cutter 6 to reciprocate, namely, the extrudate 7 (cylindrical strip) in the through hole 5 is cut off.

As shown in fig. 1, 2 and 3, in order to make the extrudate 7 not liable to be dislocated during cutting, the bottom of the perforation 5 is semicircular, and the oblique cutter 6 includes a blade 12 having the same shape as the semicircular shape. The semicircular bottom is arranged to provide a certain limiting effect on the extrudate 7 and prevent the extrudate 7 from displacing in a horizontal direction, the blade 12 is arranged to be in point contact with the extrudate 7 firstly when reciprocating, the point is used as a cutting inlet, the extrudate 7 is easier to cut (in the cutting process, the extrudate 7 moves, and the inclined cutter 6 needs to be driven quickly to cut the extrudate 7), particularly, the blade 12 can quickly cut into the tissues of the extrudate 7 with the minimum load during the point contact, and then the extrudate 7 is cut more quickly, the inclined cutter 6 can temporarily block the movement of the extrudate 7 during the cutting process, the extrudate 7 adapts to the resistance brought by the inclined cutter 6 through bending deformation, and the deformation is recovered when the inclined cutter 6 returns to the initial position (namely, when the inclined cutter 6 is not in contact with the extrudate 7), so that the cylindrical TPU 8 particles formed by cutting are provided with elasticity, and are enabled to quickly leave from the perforation 5, and then the next cutting is started.

As shown in fig. 1 and 2, a guide cylinder 13 for inserting the piston 11 is fixedly connected to a side wall of the mounting plate 4 adjacent to the first groove section 2, and the connecting rod 10 reciprocates between the guide cylinder 13 and the passage when the cylinder 9 operates. The guide cylinder 13 can provide guide for the connecting rod 10 and the piston 11, and the air cylinder 9 is ensured to provide stable telescopic driving for the beveling knife 6.

Example 2

The TPU particle production system provided in example 1 was used for production using the following steps, including specifically the steps of:

s1, drying 80kg of TPU granules with the hardness of 65A at 80 ℃ for 6h, then introducing the dried TPU granules into a double-screw extruder for first eutectic extrusion, drawing bars through water cooling, and cutting off, wherein the eutectic conditions are as follows:

the first-stage temperature is 140 ℃, the second-stage temperature is 150 ℃, the third-stage temperature is 160 ℃, the fourth-stage temperature is 160 ℃, the fifth-stage temperature is 160 ℃, the sixth-stage temperature is 160 ℃, the seventh-stage temperature is 130 ℃, the eighth-stage temperature is 110 ℃, the ninth-stage temperature is 90 ℃, the head temperature is 90 ℃, the rotating speed of the screw is 16HZ, and the length-diameter ratio of the screw is 48: 1;

s2, mixing the product obtained in the step S1 with 0.25kg of dicumyl peroxide and 0.125kg of stearic acid, introducing the mixture into a double-screw extruder for second eutectic extrusion, drawing strips through water cooling, and cutting off, wherein the eutectic conditions are as follows:

the first-stage temperature is 140 ℃, the second-stage temperature is 150 ℃, the third-stage temperature is 160 ℃, the fourth-stage temperature is 160 ℃, the fifth-stage temperature is 160 ℃, the sixth-stage temperature is 160 ℃, the seventh-stage temperature is 130 ℃, the eighth-stage temperature is 110 ℃, the ninth-stage temperature is 90 ℃, the head temperature is 90 ℃, the rotation speed of the screw is 16HZ, and the length-diameter ratio of the screw is 48: 1;

s3, mixing 0.125kg of stearic acid, 0.25kg of 2-tert-butyl-p-cresol and 0.25kg of carbon black into the mixture obtained in the S2, introducing the mixture into a double-screw extruder for third eutectic extrusion, and cutting the mixture after water cooling and bracing to obtain the product, wherein the third eutectic condition is as follows:

wherein the water cooling is carried out after the first eutectic extrusion, the second eutectic extrusion and the third eutectic extrusion, and the ultrasonic treatment is 1500 w;

wherein the length of the cut particles after the third eutectic extrusion is 4mm.

Example 3

The procedure was as in example 2, except that:

the pellet length obtained by cutting after the third eutectic extrusion was 5mm.

Comparative example 1

The production is carried out by adopting a single double-screw extruder in the following steps, and the production method specifically comprises the following steps:

s1, drying 80kg of TPU granules with the hardness of 65A at 80 ℃ for 6 hours, adding 0.25kg of dicumyl peroxide, 0.25kg of stearic acid, 0.25kg of 2-tert-butyl-p-cresol and 0.25kg of carbon black into the dried TPU, uniformly mixing, introducing into a double-screw extruder for eutectic extrusion, drawing into strips by water cooling, and cutting, wherein the eutectic conditions are as follows:

the length of the pellet obtained after cutting was 4mm.

Comparative example 2

The following are in accordance with comparative example 1, with the specific difference that:

the TPU granules were also mixed with 1.5kg of diisobutylphthalate before being introduced into the twin-screw extruder.

Comparative example 3

The procedure was as in example 2, except that:

wherein the length of the cut pellets after the third eutectic extrusion is 3mm.

Comparative example 4

The procedure was as in example 2, except that:

wherein the length of the cut particles after the third eutectic extrusion is 6mm.

The TPU particles used in the examples and comparative examples described above were all polycarbonate-type TPUs.

The TPU particles obtained by drying the products obtained in the above examples 2 to 3 and comparative examples 1 to 4 were compared with the parameters of the TPU particles, and the results are shown in the following table:

note: the drying conditions of the examples and comparative examples were 80 ℃ for 5 hours and a diameter of 2mm;

the above examples and comparative examples were performed in triplicate and the data presented is the average of the triplicates.

The water content in comparative examples 1 and 2 and comparative example 6 is above 0.05%, which shows that it takes longer to reach below 0.05%, and the time is longer, wherein the water content in comparative example 2 is reduced by adding the plasticizer, but is higher than 0.05%;

the pellets of comparative example 1 were dried to show a large degree of shrinkage deformation with a shrinkage margin of 20%, the surface of the resulting TPU particles showed severe wrinkles, which severely affected the appearance morphology of the TPU particles, the shrinkage margin of comparative example 2 was 7.5%, and the shrinkage margins of examples 1 and 2 were 2.5% and 2%, respectively, which indicates that drying had little effect on the appearance of the TPU particles obtained in examples 1 and 2.

Comparative examples 3 and 4 had a water content of 0.05% or less, but their shrinkage amplitudes reached 10% and 6.7%, respectively, and had a large effect on the appearance of the resulting TPU particles.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.

Claims

1. The TPU particle production system is characterized by comprising three twin-screw extruders which are sequentially arranged and three cooling tanks which are arranged behind the extrusion end of each twin-screw extruder, wherein each cooling tank comprises a water cooling tank and a mounting plate for transversely cutting the water cooling tank into a first tank section and a second tank section, through holes for communicating the first tank section with the second tank section are formed in the mounting plate, a beveling knife for cutting an extruded product which passes through the first tank section to the second tank section is obliquely arranged on the mounting plate, the extruded product is cut into a column shape with two end faces being inclined planes, and the extruded product is cut by the beveling knife in the through holes; wherein, flowing water is arranged in the water cooling tank, the water surface in the water cooling tank is positioned at the upper position of the middle section of the perforation, and the extrudate is positioned below the water surface; the bottom of the through hole is semicircular, and the beveling knife comprises a knife edge with the same shape as the semicircular shape.

2. The TPU particle production system of claim 1, wherein the upper end surface of the mounting plate is positioned above the water-cooled tank, and a cylinder for driving the beveling knife to extend and retract is fixedly connected to the mounting plate;

the mounting plate is provided with a channel for the inclined cutter to enter and exit, the piston of the cylinder is fixedly connected with a connecting rod, and one end of the connecting rod, far away from the piston, is fixedly connected with the inclined cutter.

3. The TPU particle production system of claim 2, wherein a guide cylinder for inserting the piston is fixedly attached to a side wall of the mounting plate adjacent to the first groove section, and the connecting rod reciprocates between the guide cylinder and the passage when the cylinder is operated.

4. The TPU particle production system of any one of claims 1 to 3, wherein the two ends of the water-cooling tank are fixedly provided with an ultrasonic generator and an ultrasonic receiver, respectively.

5. TPU particles produced by the TPU particle production system of claim 4 that are plasticizer-free and are processed without a plasticizer.

6. The plasticizer-free TPU particle of claim 5 having a columnar shape with inclined faces on both ends and a columnar height of from 4 to 5mm.