JPS62220306A - Distributor for casting stock solution into mold - Google Patents

Abstract

PURPOSE:To attain a reduction in loss of raw materials, improvements in molding properties and yield at the time of manufacturing and a reduction of cost in manufacturing of a mold, by making use of a distributor whose angle of a casting hole, form and cross-sectional area of a casting hold have been specified at the time of casting a stock solution to a mold. CONSTITUTION:The titled distributor is so constituted that an angle of casting hole of the distributor 10 possesses an angle of more than 30 deg. and less than 120 deg. to a working direction of cleaning piston 9 of a high-pressure casting head at the time of casting process of a stock solution to a mold. As for a form of a casting hole 11, the hole 11 is so constituted that is possesses at least two or more pieces of cylindrical forms or at least two or more pieces of square pillarlike forms or at least one or more pieces of fan-shaped forms whose angle is more than 0 deg. and less than 120 deg. or combination form of at least two kinds of forms selected out of each of the aforementioned cylindrical, square pillarlike and fan-shaped form groups. Then a cross-sectional area of the casting hole 11 is limited so as to fall within a range of +100%--50% of the total cross-sectional area of a casting port and outlet. With this construction, a reduction in the total cost in manufacturing the mold and that in a maintenance manhour of the mold becomes possible by eliminating various defects in the mold.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to a wide variety of reaction injection molding methods (abbreviated as RIM method in case of non-explosion) such as urethane, nylon, epoxy, etc., particularly when a high-pressure foaming machine is used. Mold forms for automobile seat cushions, motorcycle seat cushions, headrests, furniture, etc. are molded using the RIM method (referred to as the high-speed cure HR1 method) using a high-speed reaction compound into a variable-angle temperature-controlled mold with good slitting. Furthermore, the present invention relates to a distributor for injecting a stock solution into a mold used in the entire field of molding semi-rigid forms such as bumper cores, bumpers, automobile exterior panel members, housings, and the like.

[Conventional technology]

Conventionally, a stock solution injection device using a combination of a runner and a film gate as shown in Fig. 1θ, or a direct type stock solution injection device with single-point injection or multi-point injection as shown in Fig. 11 was generally used. [Problems to be Solved by the Invention] In the case of a stock solution injection device using a combination of a runner and a film gate as shown in Figure 1O, (a) In order to uniformly disperse the stock solution over the entire surface of the mold (lower plate); It is necessary to provide film gates at multiple openings, and if the film gates are not installed properly, there is a drawback that air pockets, lack of thickness, etc. may occur in the slits, etc. Therefore, a large amount of advance design is required to create the mold, and
The total cost of mold creation becomes large.

(b) It also takes a lot of time and money to repair the mold if the runner or film gate is inappropriate.

eC) Since runners and film gates are usually provided at the mold slit joint where a resin seal is used, the precision of the joint is reduced and its change over time is also large.

2) Maintaining the entire mold to ensure liquid flow at the runner and film gate requires a large amount of man-hours.

(e) There is a large loss of stock solution due to the runner and film gate.

(f) For auxiliary mixing of the stock solution after injection, an after-mixer is required in most cases, which further increases the loss of the stock solution.

(g) Since a part of the runner is required, it takes time for the stock solution to reach the inside of the mold, and the stock solution is injected after the reaction has progressed considerably.

(To) Since there is a film gate, if the mold is 7 ohm, there will be a so-called collapse (co#apse) at that part.
wicks, etc. are generated.

Furthermore, in the case of a distributor for single-point injection or multi-point injection of the stock solution as shown in Figure 11, it is difficult to uniformly disperse the stock solution over the entire surface of the mold (lower mold), so the slits etc. Air pockets and underfilling occur.

2) Since the stock solution is injected directly into the mold (lower mold) surface, the surface of the product directly below the injection hole is likely to be rough.0 Various drawbacks of conventional equipment as described in (a) to (a) above In view of this, unexploded uA eliminates the various drawbacks mentioned above such as air pockets, underfill, collapse, and surface roughness in molds, reduces raw material loss that occurs with runner and film gate methods, and improves mold design. The purpose is to reduce the number of man-hours, the total cost of mold creation, and the number of man-hours for mold maintenance.

[Means to solve the problem]

In the present invention, during the process of injecting the stock solution into the mold in mold forming by various RIM methods, (a) the cleaning piston of the high-pressure injection head has an angle of 30 degrees or more and 120 degrees or less with respect to the operating direction of the cleaning piston; both 2 or more cylindrical or at least 2
It has the shape of at least one prismatic shape, or a fan shape of more than 0 and less than 360 degrees, or a combination of at least two types selected from the above groups of cylindrical, prismatic, and fan shapes. (C) and has a range from ++Oo% to -50φ of the total cross-sectional area of the inlet and outlet.

The present invention provides a distributor for injecting stock solution into a mold.

The present invention uses a high-pressure foaming machine to mold a high-speed reaction mixture into a variable-angle temperature-controlled mold with good mixing (RIIV molding method (referred to as the high-speed cure HR method in the present invention). It is also particularly suitable for use as a distributor for injecting stock solution into molds.

As shown in FIG. 1, the injection hole of the distributor for injecting the stock solution into the mold is arranged at an angle of 30 degrees or more and +20 degrees or less, preferably 45 degrees or more, with respect to the operating axis direction of the cleaning piston of the high-pressure injection head. It has an angle of 90 degrees or more. At temperatures below 30 degrees, as shown in Figure 2, it is equivalent to the conventional direct injection method using single-point injection or multi-point injection, and problems such as roughening of the product surface directly below the injection hole, air pockets, and under-filling occur. Moreover, at +2θ degrees or more, the injection liquid hits the upper mold too much, impairing the distribution function and making it impossible to use both n%. The injection hole of the stock solution injection distributor has at least two cylindrical shapes (its cross section is circular, elliptical, etc.) and at least two prismatic shapes (its cross section is triangular, square, etc.). Polygonal, and other shapes.) There is at least one fan-shaped shape greater than 0 degrees and less than 360 degrees, or selected from each group of cylindrical, prismatic, and fan-shaped. The injection holes may have a combination of shapes of at least two or more types, and the intervals between the injection holes may be at any angle. For example, Fig. 2 shows an example of a distributor for injecting a stock solution into a mold, which has four cylindrical injection holes, the angle of which is 60 degrees, and the intervals between the injection holes are 90 degrees. has two cylindrical injection holes (angle 50 degrees, injection hole spacing 60 degrees) and a 120 degree fan-shaped injection hole (angle 50 degrees, injection hole spacing 60 degrees).
This is an example of a distributor for injecting a stock solution into a mold with a combination of a 0 degree) and a 120 degree fan-shaped injection hole (angle of 80 degrees, distance from the cylindrical injection hole of 90 degrees).

The injection hole in the distributor for injecting the stock solution into the mold may have a shape other than a straight line with respect to the central axis, such as a wavy helix or a bend, in order to increase the mixing efficiency of the stock solution. One example is a bent shape.

Further, as shown in Figure 5, the injection hole may have a change in cross-sectional area or shape from the inlet to the outlet in order to increase the mixing efficiency of the stock solution as described above.

In any of the above examples, the present invention allows for extremely less loss of the stock solution than in the after mixer used for the same purpose at the time of injection of the stock solution, due to the position of the combination of the runner and film gate as shown in Figure 1O (2).

Furthermore, the total cross-sectional area of the injection hole outlet is in the range of +too% to -50%, preferably +50% to -20% of the cross-sectional area of the cleaning piston of the high-pressure injection head.
If it exceeds the flood, the linear velocity when injecting the stock solution is too low and the distribution function is poor, and if it is less than -50%, the linear velocity during the injection of the stock solution is too high and air winding on the mold surface occurs. There is a prediction that the air pocket will be released due to inclusion.

In order to improve the mixing efficiency of the stock solution and to control the distribution balance of the stock solution, it is preferable to provide a liquid reservoir as shown in FIGS. 2 and 3 at the inlet of the injection hole in the distributor.

When designing a dispenser for stock solution injection, each condition based on the above description is determined by the shape of the product to be manufactured.

In other words, the direction in which the product should be distributed and the amount to be distributed are determined by the size of the product, volume changes at each site, the position and size of slits, lips, etc., or injection conditions such as injection amount, injection time, injection pressure, etc. Figure 6 shows the high-pressure injection head (6) and distributor (10) into the mold.
) The material of the distributor (10) may be metals such as iron or stainless steel, or plastics such as polyethylene, polypropylene, or fluororesin (eg, Teflon (trade name)).

The stock solution injection distributor of the present invention is widely used in urethane, nylon,
It is effectively used not only in fields that use various RIM methods such as epoxy, but also particularly in high-speed cure HR methods.

〔Example〕

The foaming machine used in the present invention is a high-pressure foaming machine manufactured by Krauss Matsufei, and the injection conditions are: flow rate so? /
! J), injection pressure, poly &(POj'y) + I 0
oKIF/(M'izin* (Iso) 80 Kg
/(i, liquid temperature, poly, 33°C, in, 28°Q mold temperature 62°C, 1 injection amount +20Q', curing time 2 minutes.

The diameter of the cleaning piston of the high pressure injection head is 16 mm. Here, poly refers to a liquid mixture containing polyol as a main component and various auxiliary agents (foam stabilizer, blowing agent, catalyst, crosslinking agent), and iso refers to incyanate.

Example 1 Using the high-speed electron near HR method, the stock solution injection distributor shown in Fig. 2 was used, and it was installed as shown in Figs.
An automobile seat cushion having the shape shown in the figure was molded.

The diameter of all four injection holes in the distributor is 8 da. In addition to the above, it is also possible to manufacture semi-rigid foams molded by any RIM method, such as breadboard cores or hanride molded products, for automobile exterior panel parts.

Example 2 In Example 1, the distributor was changed to the one shown in Fig. 3,
It was attached and molded as shown in Figures 6 and 9.

The distributor has two cylindrical injection holes with a diameter of 79 mm.
, the thickness of the fan-shaped injection hole is 2.8 mm (the diameter of the distributor is 70 t/).

In this case, the total cross-sectional area of the injection hole is 40 inches larger than the cross-sectional area of the cleaning piston.

Comparative Example 1 In Example 1, no distributor was used, and the stock solution was injected by a single point injection method as shown in Fig. 1θ.

Comparative Example 2 In Example 1, 2 of (b) and (e) were obtained by the stock solution injection method using a runner and a film gate as shown in FIG.
It was molded using several film gates.

(The size of the film gate is sommX51 in the exit cross section.
It is m. ) Comparison column 3 In Comparative Example 2, film gates (a), (b),
The four locations (c) and (d) were provided and molded.

Table 1 shows the results of product performance and mold manufacturing cost in Examples and Comparative Examples.

Table 1 (average value of 50 pieces each) As shown in Table 1, by using the stock solution injection distributor of the present invention, moldability, yield during manufacturing, raw material loss rate, and mold design man-hours are improved. It can be seen that the total cost of mold creation and the number of man-hours for mold maintenance are significantly improved compared to the conventional technology.

〔Effect of the invention〕

The effects of using the present invention are summarized as follows.

(1) Since the injection hole has an angle of 30 degrees or more with respect to the operating axis of the cleaning piston of the high-pressure injection head, the surface of the product directly under the injection hole will not be roughened.

(11) Using a distributor designed based on the product shape, the stock solution can be distributed uniformly over the entire surface of the lower mold, so there are no drawbacks such as air pockets or underfilling.

(i1+) In the present invention, the extremely large raw material loss caused by the aftermixer, runner, and film gate is close to zero.

aV> In the case of a gun, it is possible to uniformly distribute the stock solution over the entire surface of the mold at one location.

(V) The injection pattern can also be changed by changing the distributor.
It's extremely easy. Therefore, the number of man-hours required for mold design is greatly reduced, and the total cost required for mold production is also extremely low.

(vD Also, even if the shape of the distributor is inappropriate, there is no need to modify the mold, and only the distributor needs to be improved.

(vti) This method has a large degree of freedom in selecting distributors when molding the same product, and is significantly different from the conventional runner and film gate method.

Cvni) The problems encountered in conventional runner and film gate systems, such as injection of stock solution while the reaction is progressing, so-called collapse due to the film gate, and poor sealing performance at the mating part, are completely eliminated.

(Do) Since there are no after-mixers, runners, or film gates on the mating surface of the mold, the number of maintenance steps for the entire mold is reduced.

(x) If you want to improve the mixing efficiency of the stock solution, install a liquid reservoir part (12) as shown in Figures 2 and 3, and use an injection hole as shown in Figures 4 and 5. This can be easily achieved by

As described above, by using the stock solution injection distributor of the present invention, it is possible to reduce raw material loss, dramatically improve moldability, improve yield during manufacturing, reduce mold design man-hours, and create molds. It is possible to easily achieve reductions in total costs, reductions in mold maintenance man-hours, etc.

[Brief explanation of drawings]

Figure 1 is a proper angle view of the injection hole of one embodiment of a distributor for injection into a mold, Figures 2 and 3 are respective embodiments of a distributor for injection of stock solution, and Figure 4. Fig. 5 is an example of the injection hole shape of a distributor for injecting stock solution, Fig. 6 is an example of the use of the distributor for stock solution injection, Fig. 7 is a product diagram of Example 1, and Fig. 8 is a diagram of the product of Example 1. FIG. 9 shows an installation diagram of a distributor in Example 1, FIG. 9 shows an installation diagram of a distribution device in Example 2, and FIG. 10 shows a direct-type stock solution injection device using a conventional runner and film gate. l Stock solution injection section 2 After mixer 3 Film gate 4 Mold (lower mold) 5 Runner 6 High pressure injection head 7 Mold (upper mold) 8 Inlet tube 9 Cleaning piston IO distributor 11 Injection hole Liquid reservoir

Claims (1)

[Scope of Claims] 1. In molding by reaction injection molding (referred to as RIM method), the direction of the stock solution injection hole of the distributor for injection of stock solution into the mold is set to the high pressure used during the step of injecting the stock solution into the mold. The injection hole has an angle of 30 degrees or more and 120 degrees or less with respect to the operating axis direction of the cleaning piston of the injection head, and the injection hole has at least two cylindrical shapes, at least two or more prismatic shapes, or at least one or more, and has a fan shape of more than 0 degrees and less than 360 degrees, or a combination of at least two types selected from the above groups of cylindrical, prismatic, and fan shapes, and the total cross section of the injection hole outlet. 1. A distributor for injecting a stock solution into a mold, characterized in that its area is in the range of +100% to -50% of the cross-sectional area of a cleaning piston of a high-pressure injection head. Claim 1: Using a high-pressure foaming machine, a molded foam is molded by reaction injection molding (abbreviated as high-speed cure HR method) into an angle-variable temperature control mold that has a good combination of high-speed reaction mixture. Distributor for injecting the stock solution into the mold as described in section. 3. A patent claim in which the intervals between the injection ports of a distributor for injecting stock solution into a mold are arbitrary angles, and the injection ports have a shape other than a straight line with respect to the central axis, such as wavy, spiral, bent, etc. A distributor for injecting a stock solution into a mold according to item 1 or 2. 4 In the same injection hole of the distributor for injecting the stock solution into the mold,
A distributor for injecting a stock solution into a mold according to claim 1 or 2, which has a change in cross-sectional area or shape between its inlet and outlet. 5. A distributor for injecting an undiluted solution into a mold according to claim 1 or 2, wherein a liquid reservoir is provided at the inlet of the injection hole of the distributor for injecting an undiluted solution into a mold.