JP3376286B2 - Method for producing polyamide resin molded article - 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 producing a polyamide resin molded body, and more specifically, a polyamide resin containing a reinforcing material for use in gears, rollers, wheels, etc. used under relatively high load and high temperature. The present invention relates to a method for producing a polyamide resin molded product, in which demolding of the molded product is carried out in a short time, and moreover, insufficient polymerization and sink marks are reduced.

[0002]

2. Description of the Related Art Polyamide resin moldings are often used as substitutes for metal gears, rollers, wheels, etc. for the purpose of weight reduction, oil-free operation and noise reduction. However, when used under extremely high load conditions or under normal conditions for a long period of time, the limit was exceeded, and the key groove part existing at the boundary between the polyamide resin part and the shaft sometimes broke.

Therefore, a structure has been proposed in which only the boss portion is made of metal while taking advantage of the lightweight and maintenance-free use of the polyamide resin. As a method of fixing the metal boss portion to the polyamide resin portion, a method by cold press fitting, a method of press-fitting the heat-expanded polyamide resin portion into the metal boss portion (shrink fitting method), a method of mechanically fixing with a screw, etc. Was generally done. Further, Japanese Patent No. 2622813 discloses a method of cold-press-fitting a polyamide resin portion into a knurled metal and heating the metal to fuse and integrate the polyamide resin portion and the metal.

[0004]

However, each of these methods has problems. First, in the cold press fitting method and the shrink fitting method, the fixing force between the metal boss portion and the metal boss portion is weak, and a gap may occur between the metal boss portion and the polyamide resin portion in a short period of time.

Further, the polyamide resin has a thermal expansion at a high temperature and the stress relaxation due to long-term use lowers the hugging force of the polyamide resin portion, so that the fixing force is further weakened. Due to concentration, the polyamide resin part is easily broken. Also, depending on the shape of the product, it is often impossible to install screws.
To avoid this, if the press-fitting allowance and shrinkage-fitting allowance at the time of manufacturing are taken to be large, excessive distortion will occur on the resin side, and when processing to a prescribed size or when using it as a part, that distortion causes It was sometimes destroyed.

Further, in the method in which the polyamide resin portion is cold-press-fitted into the metal and the metal is heated to fuse and integrate the two, there is a problem that the number of processing steps is large and the product becomes expensive.

For this reason, as a low cost method, a knurled metal reinforcing material is placed on a support base and then a polymerizable lactam liquid is cast to mold the material, but this occurs during the polymerization process. Due to the shrinkage, the polymer and the metal reinforcing material are displaced from each other, so that a gap is generated between them and a sink mark is generated, which causes a problem that a good product cannot be obtained. Further, when the molded body was released from the mold after the completion of the polymerization, the mold was inverted, but the molded body sometimes clung to the support, and it took time to release the molded body.

The present invention solves the above problems, is lightweight and can be used for a long period of time without oiling by taking advantage of the advantages of polyamide resin, and facilitates demolding of a polyamide resin molded product and insufficient polymerization. It is an object of the present invention to provide a method for producing a polyamide resin molded body in which the occurrence of marks and sink marks is reduced and the binding force between the polyamide resin and the reinforcing material is maintained.

[0009]

That is, the invention according to claim 1 of the present application is a method for producing a polyamide resin molded body in which a polyamide resin is bonded to and integrated with a periphery of a reinforcing plate, and at least one or more hollow-shaped castings are provided. A temperature-controllable mold having a continuous inner groove on the outer periphery of the molding part in which the mold part is arranged and further having an outer groove part for liquid storage provided on the outside thereof is prepared. After the support base is movably installed with respect to the bottom surface of the mold and the reinforcing plate is fixed to the support base, a polymerizable lactam obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to substantially anhydrous ω-lactam. Filling the inner groove while overflowing the liquid from the casting part, then sealing the shielding material so that air is not present on the liquid surface of the polymerizable lactam liquid, and then installing the upper lid to polymerize and complete the polymerization. Polyamide resin that will later remove the molded product In the manufacturing method of the form.

According to the present invention, the polymerizable lactam liquid is
Overfill the inner groove while overflowing from one or more recessed casting parts, then seal the shielding material so that air does not intervene on the liquid surface of the polymerizable lactam liquid, and then install the upper lid to polymerize the surface. It is possible to prevent insufficient polymerization and occurrence of sink marks, and it is possible to obtain at least one or more molded products in a short time of surface treatment. Then, the obtained polyamide resin hugs the reinforcing plate well by blocking the residual shrinkage stress generated during polymerization and uniformly contracts, and is also mechanically locked. It does not come off easily.

The invention according to claim 2 of the present application is in a method for producing a polyamide resin molded product in which the mold used is made of aluminum, and the mold has good thermal conductivity, and the mold is heated in a short time. Then, the polymerization time can be shortened.

The invention according to claim 3 of the present application is a method for producing a polyamide resin molded product in which an iron support is pulled out from a casting part by magnetic force and the molded product is released from the mold. The molded body can be easily demolded.

In the invention according to claim 4 of the present application, the reinforcing plate is a disk.
A method for producing a polyamide resin molded body which is a body and has one groove-shaped or convex-shaped portion along the circumferential direction of the side surface of the disk body , wherein the obtained polyamide resin shrinks uniformly during polymerization. By doing so, the polyamide resin can be hugged well on the reinforcing plate and mechanically locked, so that the polyamide resin does not easily come off from the reinforcing plate.

In the invention according to claim 5 of the present application, the reinforcing plate is a disk.
In the method for producing a polyamide resin molded body having a notch groove for preventing rotation in the thickness direction at a predetermined interval along the circumferential direction of the side surface of the disk body , the polyamide resin is reinforced. The polyamide resin does not easily come off from the plate, and the polyamide resin does not easily rotate from the reinforcing plate, so that the bonding force between the polyamide resin and the reinforcing plate is high, and it can be applied to applications such as gears, rollers and wheels.

The invention according to claim 6 of the present application is a method for producing a polyamide resin molded body in which the polymerizable lactam liquid overflowing from the inner groove is stored in the outer groove, and the polymerizable lactam liquid overflowing from the mold is easily formed. Can be collected and does not pollute the work environment.

The invention according to claim 7 of the present application is the method for producing a polyamide resin molded product, wherein the inner wall surface of the mold is a tapered surface so that the molded product can be easily demolded, and the molded product can be easily demolded. Has become.

The invention according to claim 8 of the present application is a method for producing a metal-reinforced polyamide resin molded body in which the shielding material is a metal foil, and can be reliably sealed with the metal foil.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the polyamide resin composition of the present invention .
FIG . 2 is a perspective view of a reinforcing plate used in the embodiment , FIG.
Other reinforcing plate diagonals used in polyamide resin moldings
FIG. 3 is a perspective view showing the polya obtained by the production method of the present invention.
FIG. 4 is a plan view of the mid resin molded body, FIG. 4 is a sectional view taken along line AA of FIG.
5 is a plan view of a mold used in the method for producing a polyamide resin molded body of the present invention, FIG. 6 is a sectional view taken along line BB of FIG. 5,
7 is an enlarged view of the C portion of FIG.

The polyamide resin molded body 1 produced by the method of the present invention is, for example, a disk body as shown in FIGS. 1 and 2, and has a through hole 3 in the central portion as shown in FIG.
A metal reinforcement having one groove-shaped portion 5 along the circumferential direction of the side surface 4, a predetermined interval along the circumferential direction, and a cutout groove 6 for preventing rotation along the thickness direction. Board 2
The structure is such that the polyamide resin 9 is attached to the outside of the. A tooth portion (not shown) is formed on the outer peripheral portion of the polyamide resin 9 by a subsequent machining process, and is used as a gear for high load. At the time of subsequent processing, the through hole 3 is attached to the grip of the lathe.

As the other reinforcing plate 2, as shown in FIG. 2 , a through hole 3 is formed in the central portion, one convex portion 7 is provided along the circumferential direction of the side surface 4, and a predetermined interval is provided along the circumferential direction. The shape may be such that the cutout groove 6 for preventing rotation is provided along the thickness direction. The above-mentioned one groove part 5 and convex part 7
Prevents the polyamide resin from remaining in the shrinkage stress generated during the polymerization and uniformly shrinks, so that the polyamide resin hugs well on the reinforcing plate 2 and is mechanically locked. It does not come off easily. Further, the notch groove 6 prevents the polyamide resin 9 from rotating from the reinforcing plate 2.

The mold 10 shown in FIG. 5 is a thick-walled molding portion 11 made of a metal material having a high thermal conductivity, such as aluminum.
At least one recessed casting part 12 is regularly arranged in the inner groove part 13 and the inner groove part 13 is continuous around the outer periphery of the molding part 11.
Further, on the outside thereof, the polymerizable lactam liquid overflowing from the inner groove portion 13 is collected, and the outer groove portion 14 for liquid storage for discontinuing the working environment is discontinuously provided. By making the inner groove portion 13 continuous, it is possible to prevent air from being sucked into the casting portion 12. However, the outer groove portion 14 need not be continuous.

At the center of each casting part 12 is shown in FIGS.
As shown in FIG. 3, the protrusion 15 is arranged and serves as a guide for installing the support base 16 at the center position. The support base 16 is fitted to the protrusion 15 and is movably provided on the bottom surface of the mold, and the through hole 3 is inserted to fix the reinforcing plate 2. As shown in FIG. 9, the upper lid 20 is installed on the outer peripheral wall 21 and each head of the support 16. The support 16 may have any installation structure as long as it can move with respect to the bottom surface of the mold. For example, the support base 16 may be an installation structure that can move from the bottom surface of the mold by a predetermined stroke. In addition, the wall surface of the support base 16 may be a tapered surface of 0.5 to 7 °, which facilitates demolding of the molded body 1.

FIG. 8 is a cross-sectional view of the surface of the polymerizable lactam liquid cast in the production method of the present invention, which is sealed by a shielding material, and FIG. 9 shows a polymerization process with the upper lid in the production method of the present invention. A cross-sectional view of what you are doing, and Figure 1
Reference numeral 0 represents a partial cross-sectional view of the molded product being demolded in the manufacturing method of the present invention.

In the embodiment of the present invention, however, the through hole 3 of the reinforcing plate 2 is inserted into the supporting base 16 and the reinforcing plate 2 is stably installed in the casting section 12, and the mold 10 is set to 100 mm. ~ 180
After being placed on a hot plate 23 whose temperature was adjusted to ° C, a polymerizable lactam liquid prepared by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to substantially anhydrous ω-lactam was used for each casting part 1.
2 is filled to the extent that it overflows into the inner groove portion 13 and the inner groove portion 13. At this time, the polymerizable lactam liquid overflowing from the inner groove portion 13 is contained in the outer groove portion 14.

The ω-lactam is dehydrated in a dehydration tank under reduced pressure to be substantially anhydrous and then replaced with an inert gas such as nitrogen. The ω-lactam in the dehydration tank was weighed and put into two casting tanks, and then a predetermined amount of anionic polymerization catalyst was added to one casting tank containing ω-lactam and a predetermined amount of anionic polymerization initiator. Is ω
-Drop into the other casting tank containing the lactam.

Subsequently, the shielding material 24 is sealed up to the outside of the inner groove portion 13 so that the liquid surface of the polymerizable lactam liquid is not intervened with air, and then the upper lid 20 is installed to polymerize. The shielding material 24 used here is preferably a metal foil represented by an aluminum foil. After that, the upper lid 20 is placed and the polymerization proceeds. In this way, the polymerizable lactam liquid is filled not only into each casting portion 12 but also into the inner groove portion 13 and the shielding material 24 is sealed to the outside of the inner groove portion 13 in this state. Air can be prevented from being sucked in from the gap of the mold 10, and defective products can be suppressed.

When the polymerization is completed, the upper lid 20 is removed,
Using the magnet 25, the iron support 16 is pulled out from the casting part 12 by magnetic force, and at the same time, the molded body 1 is released from the mold. Unreacted liquid monomer did not remain on the upper surface 27 of the molded body 1, and the molded body 1 having a good appearance could be obtained.

The ω-lactam used in the present invention is substantially anhydrous α-piperidone, ε-caprolactam, ω-
Laurolactam, ω-enanthlactam, ω-capryllactam, ω-decanolactam, ω-undecanolactam, etc., or a mixture of two or more thereof, and industrially advantageous lactams are ε-caprolactam and ω-laurolactam. Is.

The anionic polymerization catalyst used in the present invention is sodium hydride, lithium hydride, sodium,
A known ω-lactam polymerization catalyst such as potassium can be used, and the addition amount thereof is 0.1 to ω-lactam.
It is 2.0 mol%. The anionic polymerization initiator is, for example, N-acetyl-ε-caprolactam, isocyanate, diisocyanate, urea derivative, urethane or isocyanurate derivative, and the addition amount is ω-
The range of 0.05 to 1.0 mol% relative to the lactam is preferred.

In the above manufacturing method, the anionic polymerization catalyst is
-A method of adding an anionic polymerization initiator to a lactam and dissolving it, and then adding and mixing the anionic polymerization initiator at the time of casting, or when casting an ω-lactam containing an anionic polymerization catalyst and an ω-lactam containing an anionic polymerization initiator. Alternatively, it is adjusted by a method of adding and mixing after casting. The polymerization of ω-lactam can be carried out at a temperature of 100 to 210 ° C, preferably 130 to 180 ° C.

In carrying out the method of the present invention, oils, waxes, zinc stearate, calcium stearate, and other lubricants that do not inhibit polymerization, and carbon fiber, glass fiber, and other reinforcing materials are added in addition to the above components. Is also possible.

[0032]

The present invention will be described in more detail with reference to the following examples. Example 1 After dehydration, ε-caprolactam in the dehydration tank was weighed and put in two casting tanks, 1,250 g in one casting tank and 1,250 g in the other casting tank, 4.0 g of sodium hydride (63% oily) was added to one casting tank and dissolved, and 5.6 g of triphenyl isocyanurate was added to the other casting tank. During this period, the polymerizable lactam liquid was further mixed while flowing nitrogen in the casting tank under atmospheric pressure while raising the temperature to 125 ° C.

An aluminum mold (inner diameter 95 m) in which a supporting table as shown in FIG.
m, depth 23 mm) on a hot plate set at 170 ° C., then a through hole in the center as shown in FIG. 3, one groove along the circumferential direction of the side surface, and the circumferential direction. A reinforcing plate made of iron having four notched grooves for preventing rotation along the thickness direction was set on the support base in the casting part.

After that, the mixed polymerizable lactam solution was poured into the casting section and the inner groove section until it overflowed,
A shielding material made of aluminum foil was sealed on the surface of the polymerizable lactam liquid so that air was not present, and then an upper lid was installed to polymerize.

When the polymerization was completed, the upper lid was removed, and the iron support was pulled out from the casting part by magnetic force using a magnet, so that the molded body could be easily demolded. An unreacted liquid monomer did not remain on the upper surface of the molded product, and a molded product having a good appearance could be obtained without local sink marks.

Further, a reinforcing plate removal test was conducted on the molded polyamide resin molded body. In this reinforcing plate removal test, the molded body was placed on an autograph support base at an ambient temperature of -40 ° C, 20 ° C, and 100 ° C, and the reinforcing plate removal amount at that time while pressing the reinforcing plate was used. The load was calculated and the load when the reinforcing plate comes off was calculated. As a result, the reinforcing plate is -40 °
At C and 20 ° C., it did not come off at 50 kN, but at 100 ° C., the polyamide resin came off at 40 kN without cracking. However, it was confirmed that all of them had good bonding strength.

Comparative Example 1 A polymerizable lactam solution was poured into a casting part containing a reinforcing plate similar to that of Example 1 in a state where it did not overflow, and then sealed with a shielding material made of aluminum foil and placed on a top lid to polymerize. did. Unreacted liquid monomer remained on the upper surface of the obtained polyamide resin molded product, and a plurality of sink marks having a depth of about 10 mm were generated, resulting in poor appearance.

Comparative Example 2 After pouring the polymerizable lactam liquid into the casting part and the inner groove part in which the same reinforcing plate as in Example 1 was put, in an overflowing state, the upper lid was not sealed with a shielding material made of aluminum foil. It was left to polymerize. Unreacted liquid monomer remained on the upper surface of the obtained polyamide resin molded body, and sink marks having a depth of about 10 mm were also generated.

[0039]

As described above, in the invention described in claim 1 of the present application, the polymerizable lactam liquid overflows from one or more recessed casting parts to fill the inner groove part, and then the polymerizable lactam liquid After the shielding material is sealed so that air does not intervene on the liquid surface, the upper lid is installed and polymerization is performed, so that insufficient polymerization of the surface and occurrence of sink marks can be prevented, and surface processing can be performed at least 1 time in a short time.
Three or more molded products can be obtained, and the resulting polyamide resin hinders the residual shrinkage stress generated during polymerization and uniformly shrinks, so that it clings well to the reinforcing plate and is mechanically locked. Therefore, the polyamide resin does not easily come off from the reinforcing plate.

According to the second aspect of the present invention, since the mold used is made of aluminum, the mold has good thermal conductivity, and the mold is heated in a short time to shorten the polymerization time. There is an effect that can be.

In the invention according to claim 3 of the present application, the iron support is pulled out from the casting part by magnetic force and the molded product is released from the mold. Therefore, the molded product can be easily and easily released from the mold. There is an effect that can be.

In the invention according to claim 4 of the present application, the reinforcing plate is a circle.
Since it is a disc and has one groove or protrusion along the circumferential direction of the side of the disc , the obtained polyamide resin contracts uniformly during polymerization, which is good for the reinforcing plate. Since it is clung to and mechanically locked, the polyamide resin has the effect of not easily coming off the reinforcing plate.

In the invention according to claim 5 of the present application, the reinforcing plate is a circle.
Since it is a disk body and has a notched groove for preventing rotation in the thickness direction at a predetermined interval along the circumferential direction of the side surface of the disk body , the polyamide resin does not easily come off from the reinforcing plate. Further, since the polyamide resin is less likely to rotate from the reinforcing plate, the bonding force between the polyamide resin and the reinforcing plate is high, and the polyamide resin can be applied to applications such as gears, rollers and wheels.

According to the sixth aspect of the present invention, the polymerizable lactam liquid overflowing from the inner groove is collected in the outer groove, so that the polymerizable lactam liquid overflowing from the mold can be easily collected and the working environment is polluted. It has the effect of disappearing.

In the invention according to claim 7 of the present application, since the inner wall surface of the die is a tapered surface so that the molded body can be easily demolded, there is an effect that the molded body can be easily demolded.

In the invention according to claim 8 of the present application, since the metal foil is used as the shielding material, there is an effect that reliable sealing can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the polyamide resin molding of the present invention .
It is a perspective view of a reinforcing plate.

FIG. 2 is used in the polyamide resin molding of the invention .
It is a perspective view of another reinforcing plate.

FIG. 3 is a plan view of a polyamide resin molded body according to the present invention.
is there.

FIG. 4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a plan view of a mold used in the method for producing a polyamide resin molded body of the present invention.

6 is a sectional view taken along line BB of FIG.

FIG. 7 is an enlarged view of part C of FIG.

FIG. 8 is a cross-sectional view showing that the surface of the polymerizable lactam liquid cast in the production method of the present invention is sealed with a shielding material.

FIG. 9 is a cross-sectional view showing a state where the upper lid is polymerized in the manufacturing method of the present invention.

FIG. 10 shows a partial cross-sectional view of a molded product being demolded in the manufacturing method of the present invention.

[Explanation of symbols]

1 molded body 2 Reinforcement plate 3 through holes 5 Groove 6 Notch groove 10 mold 11 Molding part 12 Casting part 13 Inner groove 14 outer groove 15 Projection 16 Support 20 Top lid 24 Shielding material 25 magnets

Continuation of the front page (56) Reference JP-A-8-309887 (JP, A) JP-A-63-256410 (JP, A) JP-A-8-127031 (JP, A) JP-A-62-9027 (JP , A) JP 62-202717 (JP, A) JP 61-230913 (JP, A) Actual development 63-21040 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB) (Name) B29C 39/00-39/44

Claims (8)

(57) [Claims] 1. A method for producing a polyamide resin molded body in which a polyamide resin is bonded and integrated around a reinforcing plate,
A temperature-controllable mold is provided in which a continuous inner groove portion is provided on the outer periphery of a molding portion in which at least one or more recessed casting portions are arranged, and an outer groove portion for liquid storage is further provided outside thereof. A support base was movably installed on each casting part of the mold with respect to the bottom surface of the mold, and the reinforcing plate was fixed to the support base.
The polymerizable lactam liquid containing at least an anionic polymerization catalyst and an anionic polymerization initiator added to the lactam overflows from the casting part and fills the inner groove part, and then the liquid surface of the polymerizable lactam liquid is shielded to prevent air from intervening. After sealing the material,
A method for producing a polyamide resin molded product, which comprises placing an upper lid to polymerize, and releasing the molded product after the polymerization is completed. 2. The method for producing a polyamide resin molded article according to claim 1, wherein the mold used is made of aluminum. 3. The method for producing a polyamide resin molded product according to claim 1, wherein the iron support is pulled out from the casting part by magnetic force and the molded product is released from the mold. 4. The production of a polyamide resin molded article according to claim 1, 2 or 3, wherein the reinforcing plate is a disk body and has a groove portion or a convex portion along the circumferential direction of the side surface of the disk body. Method. 5. The reinforcing plate is a disk body, and the side surface of the disk body.
5. The method for producing a polyamide resin molded product according to claim 4, wherein the polyamide resin molded product has a notch groove for preventing rotation in the thickness direction at a predetermined interval along the circumferential direction. 6. The method for producing a polyamide resin molded product according to claim 1, 2 or 3, wherein the polymerizable lactam liquid overflowing from the inner groove is stored in the outer groove. 7. The inner wall surface of the mold is a tapered surface so that the molded body can be easily released from the mold.
A method for producing the polyamide resin molded product according to the description. 8. The method for producing a polyamide resin molding according to claim 1, wherein the shielding material is a metal foil.