JP3110941B2 - Polymerization method of cast polyamide resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for polymerizing a cast polyamide resin. More specifically, the present invention relates to a method in which a powdery anionic polymerization catalyst, which is strictly prohibited from humidity, is compression molded in advance, and the obtained solid is cut into molten lactam. The present invention relates to a method for polymerizing a cast polyamide resin in which the molten lactam is polymerized safely by being charged.

[0002]

2. Description of the Related Art Conventionally, cast polyamide resins have excellent wear resistance, self-lubricating properties and mechanical strength, and are widely used as sliding members. In the method for producing such a cast polyamide resin, a cylindrical mold is heated in a hot air furnace until a predetermined temperature is reached, the mold is taken out of the furnace, and a lactam polymerization solution is injected into the mold. The mold is placed in a hot blast stove again for polymerization.

[0003] Specifically, a method in which an anionic polymerization catalyst is added to and melted in a molten lactam, and then an anionic polymerization initiator is added or mixed during or after casting, or a method in which a molten lactam containing an anionic polymerization catalyst is mixed with an anionic polymerization. It was adjusted by a method of adding and mixing a molten lactam containing an application initiator at the time of casting. At this time, the operator put a predetermined amount of the anionic polymerization catalyst in the cup and put it in the storage tank of the molten lactam every two to three minutes.

[0004]

The anionic polymerization catalyst used here is sodium hydride, lithium hydride or the like, of which sodium hydride is generally used. If these anionic polymerization catalysts are left in a high humidity place, they react with atmospheric moisture to generate hydrogen gas and generate heat or ignite, or when mixed with molten lactam, generate hydrogen gas. Had the danger of.
Moreover, in the past, the operation of safely introducing the anion polymerization catalyst into the molten lactam largely depends on the experience and skill of the operator, and thus, was dangerous when the operator was replaced. For this reason, conventionally, in the polymerization method of cast polyamide resin, it has been strongly desired to safely add an anionic polymerization catalyst to molten lactam for polymerization. The present invention is intended to solve such a problem, and provides a method for polymerizing a cast polyamide resin in which a predetermined amount of an anionic polymerization catalyst can be safely added to a molten lactam to polymerize the cast polyamide resin. It is in.

[0005]

That is, a feature of the present invention is that when a polymerizable lactam liquid obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to a molten lactam is anionically polymerized in a mold, There is provided a method for polymerizing a cast polyamide resin in which a solid obtained by previously compressing a powdery anionic polymerization catalyst is used as the anion polymerization catalyst, and the cut solid is poured into a molten lactam.

The present invention also provides a method for anionic polymerization of a polymerizable lactam solution in which at least an anionic polymerization catalyst and an anionic polymerization initiator are added to a molten lactam in a mold. and the solid was taken up in the cartridge, extruding the solid <br/> anionic polymerization catalyst and by fitting the piston member within the cartridge and moved to cut the solid anionic polymerization catalyst extruded from the cartridge The method also includes a method for polymerizing a cast polyamide resin in which this is poured into a molten lactam.

[0007]

According to the method for polymerizing a cast polyamide resin of the present invention,
Since the solid obtained by compressing the powdered anionic polymerization catalyst is cut into a molten lactam and injected into the molten lactam, the densely packed solid has a smaller surface area than the powder and has poor reactivity, which is dangerous. In addition, heat generation is less likely to occur upon contact with the molten lactam. In addition, the solid matter of the anion polymerization catalyst is automatically extruded, cut into a predetermined thickness sequentially, and dropped into a storage tank for the molten lactam. Can be put in.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic view of a polymerization apparatus used in the method for polymerizing a cast polyamide resin of the present invention, FIG. 2 is a front view of an automatic catalyst charging apparatus attached to the polymerization apparatus shown in FIG. 1, and FIG. FIG. 4 is a view taken in the direction of the arrow BB in FIG.
The polymerization apparatus 1 used in the method for polymerizing a cast polyamide resin of the present invention is divided into a storage tank 2 containing an anionic polymerization catalyst in a molten lactam and a storage tank 3 containing an anionic polymerization initiator in a molten lactam. , Each storage tank 2,
Between the mixing unit 3 and the mixing unit 4, pipes 7 each having a valve 6 attached thereto are connected. Pipe 7 from each storage tank 2, 3
The molten lactam flowing out is mixed and stirred in the mixing section 4, and then poured into a mold 5 heated to 50 to 100 ° C. Then, the mold is heated to an ambient temperature of 100 to 210 °.
C, preferably in a furnace adjusted to 130-180 ° C, to polymerize the molten lactam.

In each of the storage tanks 2 and 3, a pipe 8 for supplying nitrogen and a pipe 9 for discharging nitrogen are provided, and the pressure in the tank is always kept constant. Furthermore, the storage tank 2
A catalyst automatic charging device 10 for an anionic polymerization catalyst is mounted. A metering pump (not shown) can be installed below the valve 6 provided in each of the storage tanks 2 and 3.

The molten lactam is substantially anhydrous α-piperidone, ε-caprolactam, ω-laurolactam or a mixture of two or more thereof. Industrially advantageous lactams are ε-caprolactam and ω-laurolactam. It is.

The anionic polymerization catalyst used in the present invention is a known lactam polymerization catalyst such as sodium hydride, lithium hydride, metallic sodium, metallic potassium, etc. Among them, sodium hydride is the best. On the other hand, examples of the initiator for anionic polymerization include N-acetyl-ε-
Caprolactam, isocyanate, diisocyanate,
Urea derivatives, urethanes and isocyanurate derivatives are used. The amount of addition is 0.05 to 1.
A range of 0 mol% is preferred.

In carrying out the method of the present invention, oils, waxes, zinc stearate, calcium stearate and the like, which do not inhibit polymerization, and reinforcing materials such as carbon fiber and wollastonite may be added in addition to the above components. It is possible.

The automatic catalyst charging device 10 includes a replaceable cartridge 11 into which a solid material 12 obtained by compressing a powdery anionic polymerization catalyst in advance, and an anion polymerization catalyst An extruding member 13 for extruding the solid material 12
A cutting means 14 for cutting the solid matter 12 of the anion polymerization catalyst extruded from the above, and a protective case 15 connecting the cartridge 11 and having the cutting means 14 therein.

The cartridge 11 has a thin portion 1
7 is a cylindrical body having an elongated shape, such as a circular or square shape, which can be attached to and detached from the side wall 18 of the protective case 15 at the thin portion 17. That is, the cartridge 11 fitted into the pedestal 19 of the protective case 15 is fixed to the protective case 15 by mechanically fixing the connecting member 20 to the pedestal 19 and the cartridge 11 with screws or the like.

The extruding member 13 has a function of being inserted into the cartridge 11 and moving to extrude the solid 12 of the anion polymerization catalyst. It comprises moving means 31 for reciprocating the piston body 29. The piston body 29
The rear end is fitted into a rotating shaft 33 having its rear end fixed on a support table 32 and pivots from a horizontal position to a raised state to assist in the replacement work of the cartridge 11. In the moving means 31, a pinion mounted on a rotating shaft of a motor 36 mounted on a fixed plate 35 is engaged with a rack 39 fixed to a leg 38 of a support 32, and a piston body mounted on the support 32 is provided. 29 is reciprocated.

The cutting means 14 is for cutting the solid material 12 of the anion polymerization catalyst extruded from the end of the cartridge 11 into a predetermined thickness, and the cutter 41 serves as a cutter moving means 45. And move up and down by the operation of the cylinder 42,
Cut 2 This cutting state is shown in FIG. The cutter 41 used here is a U-shaped frame 44 facing each other.
This is a linear body such as a wire connected so as to bridge to the solid material 12 of the anion polymerization catalyst, even if it comes into contact with the solid matter 12 so as to prevent the adhesion as much as possible. Of course, the cutter 41 may be a plate-shaped blade.

The protective case 15 connects the cartridge 11 and has a cutter 41 of the cutting means 14 therein, which is connected to the ceiling surface of the storage tank 2. In the figure, reference numeral 46 denotes a nitrogen supply port, which constantly supplies nitrogen into the protection case 15. The protective case 15 is provided with a steam heater jacket 47 around a half thereof for heating the inside, and has a steam inlet 48 and a steam outlet 49.

Next, the polymerization method of the cast polyamide resin is as follows. First, as shown in FIG. 5, the cartridge 11 is set in a state where it is inserted into the protrusion 25 of the lower mold 24 previously set on the base 23, and a predetermined amount of a powdery anionic polymerization catalyst (hydrogen) is placed therein. Sodium chloride)
Pressure is applied by the rod 26 of the cylinder, and this operation is repeated several times to produce the solid 12 in which the powder is solidified. Solid 1
2 is filled up to about 90% of the storage volume of the cartridge 11. This operation is performed in dry air or a nitrogen atmosphere. Even if the anion polymerization catalyst is continuously compressed, the temperature of the solid 12 is relatively stable. It is preferable for safety that the cartridge 11 filled with the solid substance 12 is stored in a nitrogen atmosphere or immersed in oil.

Next, the cartridge 11 is mounted on the automatic catalyst charging device 10. At this time, after the piston body 29 of the pushing member 13 is retracted and swung to a state of rising from the horizontal position, the cartridge 11 is removed, and the new cartridge 11 filled with the solid substance 12 is placed on the pedestal 19 of the protective case 15. And fixed to the protective case 15 by the connecting member 20. Nitrogen always supplies 46
Is supplied to the inside of the protection case 15.

The piston body 29 returned to the horizontal position is inserted into the cartridge 11 by the moving means 31, and further advanced to push out a predetermined amount of the solid substance 12 of the anionic polymerization catalyst. The advance of the piston body 29 is performed by the proximity switch 50.
The reverse is controlled by the proximity switch 51. As shown in FIG. 6, the extruded solid 12 of the anion polymerization catalyst is cut into a thickness of 10 to 20 mm by the movement of the cutter 41 by the operation of the cylinder 42, and the storage tank 2
Into the molten lactam. Solid 12
Is contacted with a molten lactam, the reaction rate is slower than when a powdered anionic polymerization catalyst is charged, and the calorific value per unit time is smaller. This is because the surface area is smaller than the powder and the reactivity is inferior.

When the solid matter 12 of the anion polymerization catalyst in the cartridge 11 is exhausted, the piston body 29 is retracted to the start position, stopped once by the operation of the switch 51, and then swung up from the horizontal position. The cartridge 11 can be removed.

The molten lactam (eg, substantially anhydrous ε-caprolactam) contained in the storage tank 2
When a predetermined amount of the solid matter 12 of the anion polymerization catalyst is charged therein, the molten lactam and the anionic polymerization initiator, for example, the molten lactam containing trisphenyl isocyanurate, which has been charged into the other storage tank 3, flow out. After mixing and stirring in the mixing section 4, this is preliminarily set at 50 to 100 °.
Pour into mold 5 preheated to C, and ambient temperature 100-2
Polymerization can be carried out in a furnace adjusted to 10 ° C.

[0023]

As described above, in the method for polymerizing a cast polyamide resin according to the present invention, a powdery anionic polymerization catalyst is compressed into a solid, which is cut into a predetermined thickness and then put into a molten lactam. For this reason, the solidified solid has an effect that the surface area is smaller than the powder and the reactivity is lower than that of the powder, the danger is reduced accordingly, and the heat is hardly generated at the time of contact with the molten lactam. Moreover, the solid matter of the extruded anion polymerization catalyst is automatically and sequentially cut to a predetermined thickness and dropped into a molten lactam storage tank, so that the anion polymerization catalyst can be safely supplied without depending on the operator. .

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for polymerizing a cast polyamide resin using an automatic catalyst charging apparatus for molding a cast polyamide resin of the present invention.

FIG. 2 is a front view of the automatic catalyst charging device for molding a cast polyamide resin of the present invention.

FIG. 3 is a view taken along the line AA of FIG. 2;

FIG. 4 is a view taken in the direction of arrows BB in FIG. 3;

FIG. 5 is an explanatory view showing a state in which a solid substance of an anion polymerization catalyst is stored in a cartridge in advance.

FIG. 6 is a perspective view showing a state in which a solid of the extruded anion polymerization catalyst is automatically cut to a predetermined thickness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polymerization apparatus 2 Storage tank 3 Storage tank 4 Mixing part 5 Die 10 Catalyst automatic charging apparatus 11 Cartridge 12 Solid 13 Extruded member 14 Cutting means 15 Protective case 29 Piston body 31 Moving means

Claims (4)

(57) [Claims] When a polymerizable lactam liquid obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to a molten lactam is anionically polymerized in a mold, a powdery anionic polymerization catalyst is previously compressed as the anion polymerization catalyst. A method for polymerizing a cast polyamide resin, comprising using a solid obtained by the above method and cutting the cut product into a molten lactam. Upon wherein anionic polymerization in a mold at least anionic polymerization catalyst and an anionic polymerization initiator was charged polymerizable lactam solution in a molten lactam, a powdery solid anionic polymerization catalyst obtained by compressing It is housed in a cartridge, a piston member is inserted into the cartridge and moved to extrude the solid of the anion polymerization catalyst, cut the solid of the anion polymerization catalyst extruded from the cartridge, and put this into a molten lactam. A method for polymerizing a cast polyamide resin, comprising: 3. The method for polymerizing a cast polyamide resin according to claim 2, wherein the solid matter of the anionic polymerization catalyst extruded from the cartridge is cut under a nitrogen atmosphere. 4. The powdery anionic polymerization catalyst is a hydrogenated sodium anion catalyst.
The method for polymerizing a cast polyamide resin according to claim 1, wherein the polymer is lithium.