JP2000084954A - Production of polyamide resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyamide resin molding which facilitates the demolding of the molding, controls an insufficient polymerization to reduce generation of sinks, and keeps the bond strength between a reinforcing material and the polyamide resin. SOLUTION: In a method for producing a polyamide resin molding in which the resin is bonded/integrated to/with the periphery of a reinforcing plate, a temperature adjustable mold 10 in which an inner channel part 13 connected to the periphery of a molding part 11 in which at least one recessed injection part 12 is arranged is formed, and an outer channel part 14 for storing liquid is formed on the outside of the inner channel part 13 is prepared, after a support base 16 being fitted freely movably to a mold bottom surface to each injection part of the mold 10 to fix the reinforcing plate 2 to the support base 16, a polymerizable lactam liquid is packed to the inner channel part while being made to overflow from the injection part, after the surface of the lactam liquid being sealed with a shielding material 24 to exclude air, an upper lid is placed, polymerization is done, and a molding is demolded after the completion of the polymerization.

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 article, and more particularly, to a polyamide resin containing a reinforcing material used for gears, rollers, wheels, etc. used under relatively high loads and high temperatures. The present invention relates to a method for producing a polyamide resin molded article in which demolding of the molded article is performed in a short time, and in which insufficient polymerization and sink marks are reduced.

[0002]

2. Description of the Related Art Polyamide molded articles are often used as substitutes for metal gears, rollers, wheels, etc. for the purpose of weight reduction, oil-free operation, noise reduction, and the like. However, when used under extremely high load conditions or when used under normal conditions for a long period of time, the limit may be exceeded, and breakage may occur from the key groove existing at the boundary between the polyamide resin portion and the shaft.

For this reason, a structure has been proposed in which only the boss portion is made of metal while taking advantage of the features that the polyamide resin is lightweight and maintenance-free and can be used for a long period of time. As a method of fixing the metal boss portion to the polyamide resin portion, a method of cold press-fitting, a method of press-fitting the heated and expanded polyamide resin portion into the metal boss portion (shrink fitting method), a method of mechanically fixing with a screw, etc. Was commonly done. Japanese Patent No. 2622813 discloses a method in which a polyamide resin portion is cold-pressed into knurled metal, and the metal is heated to fuse and integrate the polyamide resin portion and the metal.

[0004]

However, each of these methods has its own problems. First, in the cold press-fitting method and the shrink-fitting method, the fixing force between the metal boss portion and the polyamide resin portion is sometimes short in a short time.

Further, the holding force of the polyamide resin portion is reduced by thermal expansion of the polyamide resin at a high temperature and relaxation of stress due to long use, and the fixing force is further reduced. Concentration makes the polyamide resin part easily broken. In some cases, screws cannot be attached depending on the product shape.
To avoid this, if the press-fitting margin and shrink-fitting margin at the time of manufacture are set to be large, excessive distortion will occur on the resin side, and when processing to a predetermined size or when using as a part, the distortion will cause Sometimes it was destroyed.

Further, the method of cold-pressing a polyamide resin portion into a metal, heating the metal, and fusing and integrating the both has a problem that the number of processing steps is large and the product is expensive.

For this reason, as a low-cost method, a metal reinforcing material subjected to knurling is placed in a mold and then molded by pouring a polymerizable lactam liquid, but this occurs during the polymerization process. A gap is generated between the polymer and the metal reinforcing material due to shrinkage due to the shrinkage, and a sink occurs to cause a problem that a good product cannot be obtained. Further, when removing the molded article after the completion of the polymerization, the mold was turned upside down, but the molded article was sometimes hugged by the support, and it took time to remove the molded article.

The present invention solves these problems, and makes use of the advantages of polyamide resins, is lightweight, can be used for a long time without lubrication, facilitates demolding of polyamide resin molded articles, and causes insufficient polymerization. It is an object of the present invention to provide a method for producing a polyamide resin molded article in which the occurrence of shrinkage and sink marks is reduced and the bonding strength between the polyamide resin and the reinforcing material is maintained.

[0009]

That is, the invention according to claim 1 of the present application relates to a method for manufacturing a polyamide resin molded body in which a polyamide resin is bonded to and integrated with a reinforcing plate. A continuously adjustable inner groove is provided around the outer periphery of the molding section where the mold section is arranged, and a temperature-adjustable mold having an outer groove section for the liquid reservoir is further provided on the outside thereof. A polymerizable lactam obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to substantially anhydrous ω-lactam after fixing a reinforcing plate to the support by arranging a support base movably with respect to a mold bottom surface. The liquid was filled up to the inner groove part while overflowing from the casting part, and then the sealing material was sealed so as not to allow air to intervene on the liquid surface of the polymerizable lactam liquid, and then the upper lid was placed and polymerized, and the polymerization was completed. Polyamide resin to release the molded body afterwards In the manufacturing method of the form.

According to the present invention, the polymerizable lactam liquid is
Fill the inner groove part while overflowing from one or more hollow casting parts, then seal the shielding material so that air does not intervene on the liquid surface of the polymerizable lactam liquid, then install the upper lid and polymerize, Insufficient polymerization and sink marks can be prevented, and at least one molded body can be obtained in a short time in surface processing. Then, the obtained polyamide resin prevents the residual shrinkage stress generated during the polymerization and uniformly shrinks, so that it is well hugged to the reinforcing plate and is also mechanically locked, so that the polyamide resin is removed from the reinforcing plate. It does not come off easily.

The invention according to claim 2 of the present application resides in a method for producing a polyamide resin molded article in which a mold to be 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.

[0012] The invention according to claim 3 of the present application is a method for manufacturing a polyamide resin molded body, in which an iron support base is pulled out from a casting part by magnetic force, and the molded body is released from a mold. The molded article can be easily removed from the mold.

[0013] The invention according to claim 4 of the present application is a method for producing a polyamide resin molded article in which the reinforcing plate has one groove-shaped portion or a convex portion along the circumferential direction of the side surface. Because the resin shrinks uniformly during polymerization, it satisfactorily embraces the reinforcing plate and is also mechanically locked,
The polyamide resin does not easily come off the reinforcing plate.

According to a fifth aspect of the present invention, there is provided a method for producing a polyamide resin molded article, wherein the reinforcing plates are provided at predetermined intervals along the circumferential direction and have notches for preventing rotation in the thickness direction. Yes, the polyamide resin does not easily come off the reinforcing plate, and the polyamide resin does not easily rotate from the reinforcing plate, so that the bonding strength between the polyamide resin and the reinforcing plate is high, and it can be applied to gears, rollers, wheels, etc. it can.

The invention according to claim 6 of the present application is a method for producing a polyamide resin molded product in which the polymerizable lactam liquid overflowing from the inner groove portion is stored in the outer groove portion, and the polymerizable lactam solution overflowing from the mold is easily removed. It can be collected and does not pollute the working environment.

The invention according to claim 7 of the present application resides in a method for producing a polyamide resin molded article in which the inner wall surface of a mold is tapered so that the molded article can be easily removed from the molded article. Has become.

The invention according to claim 8 of the present application is a method for producing a metal-reinforced polyamide resin molded article 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 is a plan view of a polyamide resin molded article obtained by the production method of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. FIG. 4 is a perspective view of a reinforcing plate used, FIG. 4 is a perspective view of another reinforcing plate used in the polyamide resin molded article of the present invention,
5 is a plan view of a mold used in the method for producing a polyamide resin molded article of the present invention, FIG. 6 is a cross-sectional view taken along line BB of FIG.
FIG. 7 is an enlarged view of a portion C in FIG.

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

As shown in FIG. 4, another reinforcing plate 2 has a through hole 3 in the center, one convex portion 7 along the circumferential direction of the side surface 4, and a predetermined interval along the circumferential direction. And may have a cutout groove 6 for preventing rotation along the thickness direction. The one groove-like portion 5 and the convex portion 7
Is because the polyamide resin prevents shrinkage stress generated during polymerization from remaining, and uniformly shrinks, and is satisfactorily held on the reinforcing plate 2 and is also mechanically locked. It does not come off easily. The notch 6 prevents the polyamide resin 9 from rotating from the reinforcing plate 2.

The mold 10 shown in FIG. 5 has a thick molded portion 11 made of a metal material having high thermal conductivity, for example, aluminum.
At least one or more recessed casting parts 12 are regularly arranged on the inside, and a continuous inner groove part 13 is formed around the outer periphery of the molding part 11.
In addition, an outer groove portion 14 for collecting a polymerizable lactam liquid overflowing from the inner groove portion 13 outside the inner groove portion 13 to prevent contamination of the working environment is provided discontinuously. By making the inner groove portion 13 continuous, suction of air into the casting portion 12 can be prevented. However, the outer grooves 14 need not be continuous.

FIGS. 6 and 7 show the center of each casting part 12.
As shown in FIG. 5, the projection 15 is arranged and serves as a guide for setting the support base 16 at the center position. The support base 16 is fitted to the projection 15 and is provided movably with respect to the bottom surface of the mold. The through hole 3 is inserted to fix the reinforcing plate 2. The upper lid 20 is installed on the outer peripheral wall 21 and each head of the support base 16. The support base 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 have an installation structure that is movable from the bottom of the mold by a predetermined stroke. Further, the wall surface of the support base 16 may have a tapered surface of 0.5 to 7 °, which makes it easier to remove the molded body 1 from the mold.

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 with a shielding material. FIG. Cross section, and Figure 1
0 shows a partial cross-sectional view of the molded article being released from the mold in the production method of the present invention.

Thus, in the embodiment of the present invention, the through-hole 3 of the reinforcing plate 2 is inserted into the support 16, and the reinforcing plate 2 is stably installed on the casting part 12, and ~ 180
After being placed on a hot plate 23 controlled at a temperature of ° C., a polymerizable lactam liquid obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to substantially anhydrous ω-lactam was added to each casting part 1.
2 and to the extent that it overflows into the inner groove 13. At this time, the polymerizable lactam liquid overflowing from the inner groove 13 is stored in the outer groove 14.

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

Subsequently, the shielding material 24 is sealed to the outside of the inner groove portion 13 so that air does not intervene on the liquid surface of the polymerizable lactam liquid, and then the upper lid 20 is installed to perform polymerization. The shielding material 24 used here is preferably a metal foil represented by an aluminum foil. Then, the polymerization is advanced by placing the upper lid 20. As described above, the polymerizable lactam liquid is filled to the extent that it overflows not only into each casting portion 12 but also into the inner groove portion 13. In this state, when the shielding material 24 is sealed to the outside of the inner groove portion 13, the shielding material 24 and the metal are filled. It is possible to prevent air from being sucked from the gap of the mold 10 and to suppress the occurrence of defective products.

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

The ω-lactam used in the present invention is substantially anhydrous α-piperidone, ε-caprolactam, ω-lactam.
Laurolactam, ω-enantholactam, ω-caprylactam, ω-decanolactam, ω-undecanolactam, or a mixture of two or more thereof. Industrially advantageous lactams are ε-caprolactam and ω-laurolactam. It is.

Further, the anionic polymerization catalyst used in the present invention includes sodium hydride, lithium hydride, sodium,
Known ω-lactam polymerization catalysts such as potassium can be used, and the amount of addition is 0.1 to ω-lactam.
2.0 mol%. Examples of the anionic polymerization initiator include N-acetyl-ε-caprolactam, isocyanate, diisocyanate, urea derivative, urethane, and isocyanurate derivative.
The range of 0.05 to 1.0 mol% with respect to the lactam is preferred.

In the above production method, the anionic polymerization catalyst
A method of adding and mixing an anionic polymerization initiator after or after adding and dissolving to a lactam, or a method of 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. Further, 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, other than the above-mentioned components, oils, waxes, lubricants such as zinc stearate and calcium stearate, which do not inhibit polymerization, and reinforcing materials such as carbon fiber and glass fiber are added. 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 a dehydration tank was weighed and put into two casting tanks, and after putting 1,250 g into one casting tank and 1,250 g into the other casting tank, 4.0 g of sodium hydride (63% oil) was added and dissolved in one casting tank, and 5.6 g of triphenylisocyanurate was added to the other casting tank. During this time, the polymerizable lactam solution was mixed while the temperature was raised to 125 ° C. while flowing nitrogen in the casting tank under atmospheric pressure.

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

After that, the above-mentioned mixed polymerizable lactam solution was poured into the casting portion and the inner groove portion until it overflowed.
After a shielding material made of an aluminum foil was sealed on the liquid surface of the polymerizable lactam liquid so as not to allow air to intervene, an upper lid was provided to perform polymerization.

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

A test for removing a reinforcing plate from the molded body made of a polyamide resin was conducted. This reinforcing plate removal test was performed by placing the molded body on a support stand of an autograph at an environmental temperature of -40 ° C, 20 ° C, and 100 ° C, and pressing the reinforcing plate while pressing the reinforcing plate. The load was determined, and the load when the reinforcing plate came off was determined. As a result, the reinforcing plate is -40 °
C, the resin did not come off at 50 kN at 20 ° C., but at 100 ° C., the polyamide resin came off at 40 kN without cracking. However, it was confirmed that all had good bonding strength.

COMPARATIVE EXAMPLE 1 A polymerizable lactam solution was poured into a casting section containing a reinforcing plate similar to that in Example 1 without overflowing, and then sealed with a shielding material made of aluminum foil, and an upper lid was placed to polymerize. did. Unreacted liquid monomer remained on the upper surface of the obtained polyamide resin molded body, and a plurality of sink marks having a depth of about 10 mm were generated, resulting in poor appearance.

COMPARATIVE EXAMPLE 2 A polymerizable lactam solution was poured into the casting part and the inner groove part in which a reinforcing plate similar to that in Example 1 was put, in a state of overflowing, and the upper lid was not sealed with a shielding material made of aluminum foil. Placed and polymerized. Unreacted liquid monomer remained on the upper surface of the obtained polyamide resin molded product, and again sink marks with a depth of about 10 mm occurred.

[0039]

As described above, according to the first aspect of the present invention, the polymerizable lactam liquid is filled up to the inner groove while overflowing from one or more hollow casting parts. After sealing the shielding material so that air does not intervene on the liquid surface, the upper lid is placed and polymerization is performed. Therefore, insufficient polymerization of the surface and generation of sink marks can be prevented, and surface processing can be performed at least in a short time.
One or more molded bodies can be obtained, and the obtained polyamide resin prevents shrinkage stress generated during polymerization from remaining and shrinks uniformly, so that it is well hugged to the reinforcing plate and mechanically locked. Therefore, there is an effect that 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 temperature of the mold is raised in a short time to shorten the polymerization time. There is an effect that can be.

According to the third aspect of the present invention, the iron support is pulled out from the casting part by magnetic force, and the molded body is released from the mold. The molded body can be easily and easily released. There is an effect that can be.

In the invention according to claim 4 of the present application, since the reinforcing plate has one groove-shaped portion or convex portion along the circumferential direction of the side surface, the obtained polyamide resin uniformly shrinks during polymerization. By doing so, the resin is satisfactorily held on the reinforcing plate and also mechanically locked, so that there is an effect that the polyamide resin does not easily come off from the reinforcing plate.

According to the fifth aspect of the present invention, since the reinforcing plate is provided at predetermined intervals along the circumferential direction and has cutout grooves for preventing rotation in the thickness direction, the polyamide resin can be removed from the reinforcing plate. The polyamide resin does not easily come off, and the polyamide resin is less likely to rotate from the reinforcing plate, so that the bonding strength between the polyamide resin and the reinforcing plate is high, and the polyamide resin can be applied to gears, rollers, wheels, and the like.

In the invention according to claim 6 of the present application, the polymerizable lactam liquid overflowing from the inner groove portion is stored in the outer groove portion, so that the polymerizable lactam liquid overflowing from the mold can be easily collected, and the working environment is contaminated. It has the effect of disappearing.

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

According to the eighth aspect of the present invention, since the metal foil is used as the shielding material, there is an effect that the sealing can be surely performed.

[Brief description of the drawings]

FIG. 1 is a plan view of a polyamide resin molded article according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view of a reinforcing plate used in the polyamide resin molded article of the present invention.

FIG. 4 is a perspective view of another reinforcing plate used in the polyamide resin molded article of the present invention.

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

FIG. 6 is a sectional view taken along line BB of FIG. 5;

FIG. 7 is an enlarged view of a portion C in FIG. 6;

FIG. 8 is a cross-sectional view in which the surface of a 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 in which polymerization is performed with a top lid in the production method of the present invention.

FIG. 10 is a partial cross-sectional view showing a state where a molded article is released from a mold in the production method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molded body 2 Reinforcement plate 3 Through hole 5 Groove part 6 Notch groove 10 Die 11 Molding part 12 Casting part 13 Inner groove part 14 Outer groove part 15 Projection part 16 Support stand 20 Top cover 24 Shielding material 25 Magnet

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F204 AA29 AD03 AH04 AH12 EA03 EA04 EB12 EF01 EF05 EF27 EK25

Claims (8)

[Claims] 1. A method for producing a polyamide resin molded body in which a polyamide resin is bonded to and integrated around a reinforcing plate,
Providing a temperature-adjustable mold having a continuous inner groove around the outer periphery of the molded part provided with at least one or more hollow casting parts, and further having an outer groove for a liquid reservoir on the outside thereof, After setting a support base movably with respect to the bottom of the mold at each casting part of the mold and fixing the reinforcing plate to the support base, substantially anhydrous ω-
A polymerizable lactam solution obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to a lactam is filled from the casting portion to the inner groove while overflowing from the casting portion. After sealing the material,
A method for producing a polyamide resin molded article, comprising: installing a top lid, polymerizing, and removing the molded article after the polymerization is completed. 2. The method according to claim 1, wherein the mold used is made of aluminum. 3. The method for producing a polyamide resin molded article according to claim 1, wherein the iron support is pulled out from the casting part by magnetic force, and the molded article is released from the mold. 4. The reinforcing plate has one groove or convex along the circumferential direction of the side surface.
The method for producing a polyamide resin molded article according to the above. 5. The method for producing a polyamide resin molded article according to claim 4, wherein the reinforcing plate is provided at predetermined intervals along a circumferential direction and has cutout grooves for preventing rotation in the thickness direction. 6. The method for producing a polyamide resin molded article according to claim 1, wherein the polymerizable lactam liquid overflowing from the inner groove is stored in the outer groove. 7. The mold according to claim 1, wherein the inner wall surface is tapered so that the molded body can be easily removed from the mold.
The method for producing a polyamide resin molded article according to the above. 8. The method according to claim 1, wherein the shielding material is a metal foil.