JPH0796235B2 - Injection device for undiluted solution for plastics molding - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in an apparatus for injecting an undiluted solution for molding into a mold for molding plastics such as plastic lenses and plate-shaped plastics.

[Prior Art] Conventionally, when molding a plastic lens, for example, when molding a plastic lens, there have been the following two general methods for injecting the molding solution into the cavity of the mold. That is, (1) As shown in FIG. 8, in order to form the lens-like cavities 26 between the mold 28 and the mold 29, with respect to the mold assembly mold 13a fixed via the gasket 23,
After sealing the injection port 25 with the adhesive tape 20, the injection needle 10 is pierced into the tape portion covering the injection port to inject the monomer, or (2) or the mold 28 and the mold 29 as shown in FIG. Inserting the injection needle 10 into the injection port 25 of the gasket 23 with respect to the mold assembly mold 13b in which the space between and is fixed via the gasket 23 instead of the adhesive tape 20, and injecting an amount of monomer substantially equivalent to the cavity volume. After that, it is a means to put a wooden plug in the inlet.

[Problems to be Solved by the Invention] However, in any of the above means (1) and (2), the material of the injection needle 10 is hard and the opening size of the injection port 25 is indefinite depending on the type of lens. Because there is an injection needle
When 10 is inserted into the mold assembly molds 13a and 13b from the injection port 25, the tip of the injection needle 10 comes into contact with the inner wall surfaces of the molds 28 and 29, and the molding surface is damaged.

Further, when the type of lens to be molded is different, the thickness around the cavity 26 of the mold assembling molds 13a and 13b is different accordingly, and the injection needle 10 having a diameter matching this thickness must be used. For example, a mold 28 for a lens for hyperopia,
In 29, since the outer peripheral portion is thin despite the thick central portion of the lens, the opening size of the injection port 25 is 1.2 mm in width,
The length of the mold in the circumferential direction is about 10 mm, and the width is very narrow, and the outer diameter of the injection needle 10 is also 1 mm.
Therefore, there is a problem that a thin needle must be used, and it takes a very long time to inject the stock solution into the cavity 26.

The present invention solves the above-mentioned problems, and for a mold assembly mold having a narrow injection port width depending on the type of lens to be molded, without damaging the molding surface of the mold, and in a short time within the mold cavity. It is an object of the present invention to provide an injection device for a plastics molding stock solution capable of injecting a plastics molding stock solution into a container.

[Means for Achieving the Object] In order to achieve the above object, the configuration of the injection device for a plastics molding stock solution according to the present invention is such that the plastics molding stock solution is inserted into the injection port of the plastics molding mold. A stock solution injection pipe for injecting into the cavity of the mold, a stock solution supply means connected to the stock solution injection pipe, a stock solution suction pipe for sucking the stock solution overflowing from the stock solution inlet, and a stock solution suction tube And a vacuum sensor that communicates with the stock solution suction pipe and detects the degree of vacuum in the stock solution suction pipe, and a stock solution stop means that stops the injection of the stock solution according to a detection signal of the vacuum sensor. The tip of the stock solution injection pipe is made of synthetic resin, and
It is characterized in that it is covered with a tube having a flat cross-sectional shape at its tip.

In this case, the tube is preferably made of any one of polyolefin resin, polyvinyl chloride resin, and polytetrafluoroethylene resin, and has a thickness of 0.1 to 0.8 mm. The mold is
It is preferable that the mold is a plastic lens molding mold and the undiluted solution for plastics molding is a plastic lens molding monomer.

[Operation] According to the injection device of the present invention, when the stock solution injection pipe is inserted into the stock solution injection port of the die-molded mold placed on the V block, the material of the injection pipe is made of synthetic resin. Since the tube is covered, even if the injection tube comes into contact with the inner wall surface of the mold, the molding surface is not damaged.

Further, since the cross-sectional shape of the tip of the tube is flat, even if the width of the mold assembly mold is narrow, the injection pipe can be easily inserted into the cavity through the injection port.

[Embodiment] Hereinafter, the content of the present invention will be specifically described with reference to the drawings showing an embodiment thereof.

FIG. 1 is a front view of a plastic lens molding stock solution injection device 1 according to an embodiment of the present invention, FIG. 2 is a right side view of FIG. 1, and FIG. 3 is a monomer injection of FIG. It is an enlarged view of a part.

In the figure, 13a is a mold-molding mold into which the monomer 18 described in FIG. 8 is to be injected, and in the present embodiment, four are mounted on the V block 12 fixed on the base 2. The mold assembly mold 13a is fixed on a support plate 14 while standing on the V block 12, and the height of the injection port 25 is adjusted by the support plate 14 according to the lens diameter to be molded. The V-block 12 can be slid up and down, and the V-block 12 can be fixed on the base 2 by a pin (not shown). Therefore, the injection port 25 of the mold assembly mold 13a can be positioned and positioned just below the injection needle 10.

1a to 1d are monomer injecting machines for injecting the monomer 18 into the mold assembling mold 13a, and a frame box 3 erected from the base 2 allows a constant injection from an inlet 25 corresponding to the mold assembling mold 13a. It is fixed at the height. Each of the monomer injecting machines 1a to 1d includes a slider unit 5 and a guide 3a provided with the slider unit 5 on the frame box 3.
And an up-down air cylinder 6 that moves up and down along the direction.

The slider unit 5, as shown in FIG.
a, injection needle 10 which is a monomer injection tube, thin-walled tube 22 inserted at the tip of injection needle 10, monomer suction tube 27, needle holder 1
1, a tube joint 24, a silicon tube 19, a flow rate control valve 8 and an air cylinder 9 for a valve. The silicon tube 19 has a Teflon (registered trademark)
Monomer supply means which is a stock solution supply means via the tube 7.
It is connected with 31. Therefore, the monomer 18 is obtained from the monomer supply means 31 by the Teflon (registered trademark) tube 7, the silicone tube 19, the tube joint 24, the needle holder.
11, mold injection mold 10 through injection needle 10 and thin-walled tube 22
In addition to being able to supply a, the flow rate adjusting valve 8 and the valve air cylinder 9 can adjust the supply amount and stop the supply.

Here, as the monomer supply means 31, for example, supply by a gas pump, pressurized supply by an inert gas such as nitrogen, or the like can be used.

Further, as the injection needle 10 which is a stock solution injection pipe, its inner diameter may be determined according to the size of the injection port 25, the volume of the cavity 26, etc., but its material is, for example, stainless steel, aluminum or the like corrosion resistance. Some metals are preferred.

Further, as the stock solution stopping means, the valve air cylinder 9 is used in the present embodiment, but in addition, a solenoid valve, a diaphragm valve or the like can be used, and a diaphragm valve whose valve seat does not come into contact with the monomer is preferable.

Next, the monomer suction pipe 27, which is a stock solution suction pipe, is provided with suction means 21 for sucking the monomer overflowing from the injection port 25 of the mold assembly mold 13a and then collecting the monomer into the monomer collection container 15. These are connected to each other by discharge pipes 30a and 30b. As the suction means 21, any means may be used as long as it can generate an ultimate vacuum of about 200 to 400 mmHg in the discharge pipe 30a, and for example, an oil rotary vacuum pump, a water ring pump, an ejector or the like can be used. Reference numeral 4 denotes a control means for detecting a change in the degree of vacuum in the suction pipe 27 when sucking the monomer overflowing from the inlet 25 and controlling this signal.
The vacuum sensor sent to 32, and 16 are vacuum gauges for detecting the degree of vacuum of the monomer suction means 21.

The vacuum sensor 4 is not particularly limited and may be any as long as it can detect the degree of vacuum. In order to avoid contact between the detection end and the monomer, it is sufficient to start up with a T-shaped tube as shown in the figure, but it is more preferable to use a diaphragm type.

Next, FIG. 4 is an enlarged sectional view of the injection needle 10 and the monomer suction tube 27 shown in FIG. 3, and FIGS. 5 to 7 are sectional views taken along the line XX of FIG. 4 and Y, respectively. It is a sectional view taken along the line -Y and a sectional view taken along the line ZZ, and these members will be described.

At the tip of the injection needle 10, a thin-walled tube 22 having a flat cross-sectional shape is provided so as not to scratch the inner peripheral surface of the mold.
Are connected to each other, and their cross-sectional shapes are shown in FIGS.
As shown in the figure, the injection needle 10 and the thin-walled tube 22 are formed to be reasonably flat. The thickness of the thin tube 22 is preferably 0.1 to 0.8 mm in order to maintain the shape of the injection needle and facilitate insertion into the cavity, and
1 to 0.5 mm is more preferable. Further, the material is preferably one having chemical resistance to the monomer, for example, a material made of any one of polyolefin resin, polyvinyl chloride resin, and polytetrafluoroethylene resin. Polytetrafluoroethylene resin is more preferable because it does not damage.

On the other hand, the monomer suction pipe 27 is fixed to the slider 5a in a state where the injection needle 10 and the outer peripheral surface are close to each other at a position of height H from the tip of the thin-walled tube 22. The height H is preferably adjusted according to the viscosity of the monomer to be injected into the cavity 26, but is preferably 7 to 10 mm when the stock solution for molding is a plastic lens molding monomer. In addition, when the injection needle 10 is a double tube having the inside and the monomer suction tube 22 provided outside,
It is more preferable because the injection needle and the suction tube are integrated into a single structure and the overall size is reduced.

Next, the operation of the monomer injection device will be described step by step.

(1) First, the suction means 21 is first operated so that air can be sucked from the lower end of the monomer suction pipe 27.

(2) Next, the mold assembly mold 13a or 13b is placed on the V block 12 and positioned on the base 2 so that the injection port 25 thereof is directly below the thin tube 22. In the case of the mold assembly mold 13a, the opening size of the injection port 25 is such that the size of the tape 20 turned from the end is about 10 mm. At this time, if the tape is turned over and the inlet becomes too large,
The monomer 18 is not completely filled in the cavity 26, leaving bubbles in the cavity, which causes lens molding failure.

(3) A signal is sent from the controller 32 to the valve air cylinder 9, the silicon tube 19 is pressure-bonded and closed, and then the monomer supply means 31 is operated so that the supply pressure of the monomer 18 to the silicon tube 19 is 0.5 to. Adjust so that it is about 3.0 kg / cm ² · G.

(4) A signal is sent from the controller 32 to the vertical air cylinder 6 to move the slider unit 5 downward. Injection needle 10
Is inserted into the injection port 25 of the mold assembly mold 13a. In this case, the lower end of the thin-walled tube 22 enters the inside of the cavity 26 about 5 to 8 mm from the inlet 25, and the monomer suction tube 2
The lower end of 7 is adjusted to be about 1 to 2 mm above the inlet 25. If this distance is short, the air in the cavity will be sucked out and the molded shape of the lens will be impaired, or when the monomer injection is over, the monomer in the cavity will be sucked too much,
Air bubbles remain in the cavity, which causes poor lens quality. On the other hand, if this distance is too long, the monomer which is about to overflow cannot be completely sucked from the monomer suction tube 27 and overflows, which stains the outer peripheral surface of the mold and causes a sealing failure.

(5) When the slider unit 5 reaches the lowest point, a limit switch (not shown) attached to the up / down air cylinder 6 detects it, and the slider unit 5
Is fixed to the lowest point, and at the same time, a signal is sent from the controller 32 to the valve air cylinder 9, the pressure bonding of the silicon tube 19 is released, and the monomer 18 is injected from the tip of the thin tube 22 into the cavity. At this time, by the flow rate control valve 8,
It is possible to adjust the injection rate to a proper value that matches the inner volume of the cavity.

(6) When the liquid level of the monomer 18 in the cavity 26 gradually rises and the liquid level of the monomer reaches the lower end of the monomer suction pipe 27,
Since the lower end of the monomer suction pipe is blocked by the monomer, the discharge pipe
The vacuum degree of 30a changes. The vacuum sensor 4 catches this change in the degree of vacuum, and the signal is sent to the controller 32.

On the other hand, the monomer sucked by the monomer suction pipe 27 is
It is recovered in the monomer recovery container 15 via a.

(7) About 1 second after the vacuum sensor 4 catches the change in the degree of vacuum in the discharge pipe 30a, the valve air cylinder 9 operates and the supply of the monomer 18 is cut off.

(8) The controller 32 again sends a signal to the up / down air cylinder 6 to push up the slider unit 5.

(9) Remove the mold assembly mold 13a from the V block 12 and seal the injection port 25 with the tape end. Further, in the mold assembly mold 13b assembled by the gasket 23, after similarly taking out, the injection port 25 is plugged to complete the injection.

(10) The plastic lens thus molded is finally transferred to the next polymerization step.

In the injection device 1 for the undiluted solution for molding a plastic lens shown in FIGS. 1 to 9, a stainless needle having an inner diameter of 3.2 mm is used as the injection needle 10, and a polytetrafluoroethylene having a thickness of 0.5 mm is used. For the mold assembly 13a having a cavity volume of 20cc, which covers the resin thin-walled tube 22, the lower end of the thin-walled tube 22 is located 5 mm from the opening 25, and the height of the suction pipe 27 is located at the position 2 mm from the opening 25. When the lens-forming monomer 18 was injected as described above, the monomer did not overflow from the opening at all, and the injection was possible without damaging the inner peripheral surface of the cavity.

Similarly, the cavity volume is 10cc, 20cc, 35cc, 90cc
It was also tried to inject into the mold assembly 13a, but it was possible to easily inject without additional injection.

The vacuum sensor 4 was able to catch the fullness of the monomer cavity when the vacuum level was about 200 mmHg.

[Effects of the Invention] As described above, according to the invention described in claim (1), it is inserted into the injection port of the plastics molding mold to inject the plastics molding stock solution into the cavity of the mold. A stock solution injection pipe, a stock solution supply means connected to the stock solution injection tube, a stock solution suction tube for sucking the stock solution overflowing from the stock solution inlet, a stock solution suction means connected to the stock solution suction tube, A vacuum sensor connected to the stock solution suction pipe, having a vacuum sensor for detecting the degree of vacuum in the stock solution suction pipe, and a stock solution stopping means for stopping the injection of the stock solution according to a detection signal of the vacuum sensor, and a tip of the stock solution injection pipe Since the material is made of synthetic resin and the tip portion is covered with a tube having a flat cross-sectional shape, even if the injection pipe comes into contact with the inner wall surface of the mold, the molding surface is not damaged. Also, since the cross-sectional shape of the tip of the tube is flat, even if the width of the mold assembly mold is narrow, the injection pipe can be easily inserted from the injection port into the cavity, and the stock solution can be prepared in a short time. It can be injected into the cavity.

According to the invention of claim (2),
It is easy to insert the stock solution injection pipe into the injection port, and
A product with excellent chemical resistance to monomers can be obtained.

Further, according to the invention described in claim (3), a preferable injection device of the undiluted solution for molding a plastic lens can be obtained.

[Brief description of drawings]

FIG. 1 is a front view of an apparatus for injecting a stock solution for molding plastic lenses, which is an embodiment of the present invention, FIG. 2 is a right side view of FIG. 1, and FIG. 3 is a monomer injecting section of FIG. FIG. FIG. 4 is an enlarged sectional view of the injection needle and the monomer suction tube shown in FIG. 3, and FIGS. 5 to 7 are sectional views taken along line XX and YY of FIG. 4, respectively. It is a figure and ZZ arrow sectional drawing. Further, FIG. 8 is a sectional view of a die-assembled lens whose opening is sealed with a tape, and FIG. 9 is a sectional view of a die-assembled lens whose opening is sealed with a wooden plug. Explanation of symbols in the drawings 1 …… Injection device 2 …… Base 3 …… Frame box 3a …… Guide 4 …… Vacuum sensor 5 …… Slider unit 5a …… Slider 6 …… Upper and lower air cylinder 7 …… Teflon Tube 8 …… Flow control valve 9 …… Air cylinder for valve 10 …… Injection needle 11 …… Needle holder 12 …… V block 13 …… Molding mold 14 …… Support plate 15 …… Monomer collection container 16 …… Vacuum Total 17 …… Pole 18 …… Monomer 19 …… Silicon tube 20 …… Tape 21 …… Suction means 22 …… Thin tube 23 …… Gasket 24 …… Tube joint 25 …… Inlet 26 …… Cavity 27 …… Monomer Suction pipes 28, 29 …… Molds 30a, 30b …… Discharge pipes 31 …… Monomer supply means 32 …… Control means

Claims (3)

[Claims] 1. A stock solution injection pipe that is inserted into an injection port of a plastics molding mold to inject a plastics molding stock solution into a cavity of the mold, and a stock solution supply means connected to the stock solution injection pipe. A stock solution suction pipe for sucking the stock solution overflowing from the stock solution inlet, a stock solution suction means connected to the stock solution suction tube, and a vacuum sensor connected to the stock solution suction tube for detecting the degree of vacuum in the stock solution suction tube. And a stock solution stopping means for stopping the injection of the stock solution in response to a detection signal of the vacuum sensor, the tip of the stock solution injection pipe is made of synthetic resin, and the cross-sectional shape of the tip is flat. An apparatus for injecting an undiluted solution for molding plastics, characterized by being covered with a tube. 2. A tube having a thickness of 0.1 to 0.8 mm, which is made of any one of polyolefin resin, polyvinyl chloride resin, and polytetrafluoroethylene resin, as the tube. An apparatus for injecting the undiluted solution for plastics molding according to 1). 3. The plastics molding according to claim 2, wherein the plastics molding mold is a plastic lens molding mold, and the plastics molding stock solution is a plastic lens molding monomer. Stock solution injection device.