JP3422843B2 - In-mold coat injection device and in-mold coat method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of molding a molding material made of a thermoplastic resin or a thermosetting resin in a cavity provided in a molding die, and then placing the surface of the molded article in the cavity. An in-mold coat injection device used in a so-called in-mold coating method, in which a coating such as a coating film is formed on the surface of a molded article by coating with a predetermined amount of a coating agent.
Also, the present invention relates to an in-mold coating method using such an in-mold coating injection device.

[0002]

2. Description of the Related Art Sheet molding compound (S
MC), bulk molding compound (BMC)
Molded products made of fiber reinforced thermosetting resin using
It is widely used as a substitute material for metal parts in fields such as automobile exterior panels and housing equipment. However,
In the case of molded products made of fiber reinforced thermosetting resin, it is necessary to improve the surface defects (pinholes, glass fiber patterns, etc.) of the molded products. As a surface treatment method for these, in-mold coating method (in-mold coating method) Has been adopted. By the in-mold coating method, excellent mechanical strength, dimensional stability, heat resistance and light weight can be imparted to the molded product. Further, in-mold injection equipment is widely used for coating the surface of a molded article with a predetermined amount of coating agent by the in-mold coating method.

As shown in FIG. 6, a conventionally used in-mold injection device includes a coating material injection device 60, a coating material measurement device 70, and a pipe 35 connecting the coating material injection device 60 and the coating material measurement device 70. It consists of The molding device is a compression molding device, and FIG. 6 illustrates only the mold part that constitutes the compression molding device. The mold comprises an upper mold 80 and a lower mold 81. 6 to 8, the mold is set up for the sake of drawing, but in reality, the mold is arranged in a state in which the illustrated mold is rotated 90 degrees counterclockwise. ing. A cavity 82 is provided in the upper mold 80 and the lower mold 81.
Is provided. Further, the upper die 80 is provided with a through hole 83. Generally, the coating material injection device 60 is attached to the upper mold 80.

The coating material injection device 60 includes a coating material flow path 61,
The coating agent injecting section 62 communicating with the coating agent channel 61 and the cavity 82, a part of the coating agent channel 61 and the coating agent injecting section 6
It is composed of an opening / closing pin 63 that can move in the inside 2, a hydraulic cylinder 65 for moving the opening / closing pin 63, and a cooling water chamber 64. In addition, the coating material injection device 60 includes an upper mold 80.
Is attached to the through hole 83. Coating agent measuring device 7
Zero is composed of a measuring cylinder 71 and a hydraulic cylinder 72.

As shown in the schematic partial sectional view of FIG. 10, the coating agent flow path 61 has a shape obtained by rotating a "concave" character about the axis of the opening / closing pin 63. The bottom of the coating material flow path 61 communicates with the coating material injection part 62. The coating agent flows into the coating agent flow channel 61 through the coating agent introduction flow channel 68, and the coating agent is discharged from the coating agent discharge flow channel 69. The cooling water chamber 64 is provided outside the coating agent channel 61 to cool the coating agent flowing in the coating agent channel 61.
It is provided so as to surround 1. Cooling water flows into the cooling water chamber 64 via the cooling water introducing portion 66, and is discharged from the cooling water discharging portion 67. A partition is provided at the upper part of the cooling water chamber 64. In addition, (B) of FIG.
Each of (C), (D), and (E) is shown in (A) of FIG.
11 is a cross-sectional view taken along line BB, line CC, line DD, and line E-E of FIG. 10, and FIG. 10A is a line A- in FIG.
It is sectional drawing along A.

With the coating material injection device 60 and the coating material measuring device 70 having such a structure, the coating material cavity 82 is formed.
The injection pressure inside can be set to a maximum of 2 to 35 MPa. Further, the injection amount of the coating agent is the measuring cylinder 71.
By adjusting the cylinder diameter and the stroke of the hydraulic cylinder 72, it is possible to control to several cc to 500 cc.

The coating agent supply device comprises a coating agent tank 30, a pump 31, a check valve 32, a branch valve 33 and a pipe 34. The coating material injection device 60 is supplied with the coating material 40 from the coating material supply device via the coating material measuring device 70, and the coating material 40 flowing out from the coating material injection device 60 is returned to the coating material supply device. That is, the coating material injection device 60 and the coating material supply device constitute a circulation system.

FIG. 6 shows a state in which the compression molding material 90 is compression molded in the cavity 82 formed in the upper mold 80 and the lower mold 81 in the compression molding device. The compression pressure during compression molding is usually 3.5 MPa to 14 MPa. During the compression molding of the compression molding material 90, the coating material 40 is sent by the pump 31 from the coating material tank 30 via the check valve 32 into the measuring cylinder 71 of the coating material measuring device 70, and the coating material is further supplied to the measuring cylinder 71. 71 through the pipe 35 through the coating material flow path 61 of the coating material injection device 60 (more specifically, also around a part of the opening / closing pin 63), and the coating is performed via the branch valve 33 in the open state. It is returned to the agent tank 30. The opening / closing pin 63 of the coating material injection device is the hydraulic cylinder 6
The coating material injection portion 62 is closed at the forward end by 5. In order to prevent the coating agent 40 from gelling in the coating agent flow path 61, the cooling water is continuously supplied to the cooling water chamber 64.

After the compression molding of the compression molding material is completed, the coating material is weighed. This state is shown in FIG. First, the branch valve 33 is closed. Next, the hydraulic cylinder 72 of the coating agent measuring device 70 is operated to set the piston in the measuring cylinder 71 to a predetermined position. Then, the hydraulic cylinder 65 of the coating material injection device 60 is operated to open and close the open / close pin 63.
To the rear end. As a result, the coating material 40 flows into the coating material injection portion 62. The amount of the coating material 40 thus measured is the total of the volume of the coating material stored in the measuring cylinder 71, the coating material that has flowed into the coating material injection portion 62, and the coating material that occupies a portion 61A of the coating material flow path 61. is there.

Next, the hydraulic cylinder 72 of the coating agent measuring device 70 is operated. This allows the weighing cylinder 7
The coating material 40 weighed in 1 is poured onto the surface of the compression molded product. After that, the hydraulic cylinder 6 of the coating material injection device
5 is operated to position the opening / closing pin 63 at the forward end (see FIG. 8). As a result, the coating agent that has flowed into the coating agent injection section 62 and the coating agent that occupies a portion 61A of the coating agent flow path 61 is injected into the surface of the compression molded product. Thus
A coating 40A is formed on the surface of the compression molded product. Then, the branch valve 33 is opened to return the coating material to the circulating state as shown in FIG.

Since the compression pressure by the upper die 80 and the lower die 81 at the time of injecting the coating material is set to about 14 MPa or less, the injection pressure of the coating material may be at this level. Therefore, the pipe 35 connecting the coating material measuring device 70 and the coating material injection device 60
However, even if a normal pressure-resistant rubber pipe is used, the expansion amount of the pipe 35 at the time of injecting the coating material is small, and the injection amount of the coating material or the measurement accuracy is hardly adversely affected. Also,
Molded products molded by compression molding are relatively large,
The ratio of the amount of coating material that has flowed into the coating material injection portion 62 and the like to the amount of coating material measured in the measuring cylinder 71 is small.
Therefore, the ratio of the coating agent that has flowed into the coating agent injection portion 62 and the coating agent that occupies a portion 61A of the coating agent flow path 61 is small with respect to the total amount of the coating agent that is injected onto the surface of the compression molded article, and these coatings are used. The amount of agent is negligible.

[0012]

Up to now, the in-mold coating method has been applied to fiber-reinforced thermosetting resin molded products mainly using the compression molding method as a molding means. However,
In recent years, application of the in-mold coating method has been studied as a means for molding a thermoplastic resin molded product that requires designability and surface functionality. From the viewpoints of molding method (compression molding method and injection molding method, etc.), characteristics of molding material, and coating area (coating material injection amount) due to difference in molding object, etc., high performance of the in-mold injection device is required. ing. That is, the coating material injection pressure can be increased, the measurement accuracy can be improved when a small amount of coating material is injected, the mold can be downsized, and it can be applied to small and medium-sized molding machines. In-mold coat injection equipment is required.

When the conventional in-mold coat injecting apparatus is applied to the injection molding apparatus shown in FIG. 9, the following problems occur. Incidentally, only the mold part of the injection molding device is shown in FIG. This mold comprises a fixed mold part 10 and a movable mold part 11, and a fixed mold part 10 and a movable mold part 11
A cavity 12 is provided in the. Fixed mold part 10
Is provided with a gate portion 14 which is open to the cavity 12. Further, the fixed mold part 10 is provided with a through hole 13. A coating agent injection device 60 is attached to the through hole 13. In FIG. 9, reference numeral 50 indicates the gate portion 14.
3 shows the molding material injected into the cavity 12 from

In the injection molding method, the pressure in the cavity 12 at the time of injecting the coating material is usually 20 MPa to 100 M.
It is about Pa. Therefore, the injection pressure of the coating material is required to be at this level. At such a coating material injection pressure, the coating material measuring device 70 and the coating material injection device 60 are provided.
Even if a metal fixed pipe is used as the pipe 35 that connects with, when the coating agent is injected at high pressure, the pipe expands greatly,
The amount of coating material injected becomes inaccurate or the measurement accuracy decreases. In order to prevent this, it is necessary to use a considerably thick pipe and to shorten the pipe 35, so that the workability is reduced as compared with the case where the pressure resistant rubber pipe is used. There is a problem. Further, it is extremely difficult to completely eliminate the volume expansion of the pipe. It is not possible to use normal pressure-resistant rubber pipes, as this will damage the pipes.

In comparison with the compression molding method, a relatively small molded product is often molded by the injection molding method. Therefore, even if the pipe 35 is made of a metal pipe, the ratio of the amount of the coating material that has flowed into the coating material injection portion 62 or the like to the amount of the coating material measured in the measuring cylinder 71 is large. That is, the amount of the coating material to be injected is (the amount of the coating material measured in the measuring cylinder 71) + (the amount of the coating material that has flowed into the coating material injection portion 62) + (a part 61A of the coating material flow passage 61) The amount of coating agent occupying)-(Increase in pipe volume due to expansion of pipe 35) It can be expressed by the formula (1). Therefore, when the ratio of the amount of the coating agent measured in the measuring cylinder 71 is small, the ratio of the second term of the formula (1) is relatively large, and the amount of the coating agent injected is accurately controlled. Becomes difficult. Also,
When the injection pressure of the coating material becomes high, the contribution of the fourth term of the formula (1) becomes large, making it difficult to accurately control the amount of the coating material to be injected, and further, the measurement accuracy is lowered. Depending on the case, the amount of the coating agent (represented by the second and third terms of the formula (1)) flowing into the coating agent injecting portion 62 or the like is equivalent to the coating agent to be formed on the surface of the molded article. Too much than the amount. When the surface of the molded product is coated with the coating agent in such a state, there arises a problem that the coating film on the surface of the molded product has an abnormal film thickness or the coating agent leaks from the parting surface of the mold.

Further, since a high pressure is applied to the coating agent measuring device 70, it is necessary to improve the pressure resistance of the coating agent measuring device 70, which complicates the structure of the coating agent measuring device 70 and increases mechanical strength. There is also the problem of having to.

Further, the cooling water chamber 6 is provided in the coating material injection device 60.
Providing 4 is essential for cooling the coating agent flowing in the coating agent channel 61. As a result, it becomes difficult to downsize the coating agent injection device 60 and simplify the structure. Therefore,
In the injection molding method in which relatively small molded products are often molded, the outer dimensions of the mold part to which the coating material injection device is attached must be made larger than necessary, or There is a problem that workability at the time of attachment is reduced. If the cooling water chamber 64 is deleted and the coating material injection device is miniaturized, a region where the coating material flow velocity is slow occurs in a corner portion of the coating material flow passage 61, and a coating agent retention portion is formed in the coating material. It is generated in the flow path 61. As a result, the coating material is gradually solidified by the heat from the mold, and in the worst case, the coating material flow path may be blocked.

Accordingly, it is an object of the present invention to provide an in-mold coat pouring device which makes it possible to coat the surface of a molded article with a precisely metered, predetermined amount of coating agent. Further, the object of the present invention is to provide an in-mold coat injection device capable of injecting a small amount of a precisely measured coating material at a high pressure in order to coat the surface of a molded article molded by an injection molding method. Especially. Further, the object of the present invention is to
An object of the present invention is to provide an in-mold coat injection device which can be attached to a small mold or a small-to-medium-sized molding device, has excellent workability, is miniaturized, and has a simple structure. Further, it is an object of the present invention to provide an in-mold coating method capable of forming a film having a precisely defined thickness on the surface of a molded product by using such an in-mold coating injecting device.

[0019]

[MEANS FOR SOLVING THE PROBLEMS] The in-mold coat injecting device of the present invention for achieving the above object is provided with a molding material made of a thermoplastic resin or a thermosetting resin in a cavity provided in a molding die. It is a device for coating the surface of the obtained molded product with a predetermined amount of the coating agent in the cavity after the molding. The in-mold coat injection device of the present invention measures (a) a coating agent flow path through which the coating agent flows, and (b) a coating agent which is in communication with a part of the coating agent flow path and has a tip opening into a cavity. A coating agent measuring / injecting section for: (c) a coating agent injecting means movable in the coating agent measuring / injecting section and in a part of the coating agent flow path communicating with the coating agent measuring / injecting section, And (d) a moving means for moving the coating material injecting means, wherein the tip end portion of the coating material injecting means has a forward end near the tip portion of the coating material metering / injecting portion and a coating material metering / cumulative agent. It is characterized in that it can be moved by a moving means between a trailing end that does not interfere with the flow of the coating material flowing in the portion of the coating material channel communicating with the injection part.

A preferred mode of the in-mold coat injecting apparatus of the present invention is: (A) When molding a molding material, the tip of the coating material injecting means is located at the forward end, so that the coating material of the molding material is also measured. (B) When the coating agent is measured, the front end portion of the coating material injection means is located at the backward movement end, so that a predetermined amount of the coating material that has flown into the coating material measurement / injection portion is prevented. And (C) when the surface of the molded article is coated with a predetermined amount of coating agent, the coating agent injection means is advanced to the forward end, and the coating agent that has flowed into the coating agent metering / injecting section is also used for coating agent metering. It is characterized in that it is pushed out from the tip of the injection part.

In the in-mold coat injecting apparatus of the present invention, the amount of the coating agent flowing into the coating agent measuring / injecting section is preferably 0.4 liter or less. The minimum amount of coating agent to flow into the coating agent metering / injection section depends on the area of the surface of the molded product and the thickness of the film to be formed on the surface of the molded product. Further, when the coating material is extruded from the tip of the coating material metering / injection part, the pressure applied to the coating material by the coating material injection means is preferably 100 MPa or less. The minimum pressure applied to the coating material by the coating material injection means depends on the condition of the mold (for example, mold clamping pressure) at the time of injecting the coating material, the thickness of the molded product, the compression elastic modulus of the molding material, and the like.

The coating agent passage, the coating agent inlet passage is constituted by a main coating agent passage and the coating agent discharge passage, the cross-sectional area of the main coating agent passage is the cross-sectional area of the coating agent inlet channel It is preferably 0.5 to 2 times so as not to cause a coating agent retention portion in the coating agent flow channel. It is more desirable to configure the main coating agent channel so that the cross-sectional area of the main coating agent channel does not change abruptly. Further, the coating agent flow channel has a structure in which one coating agent introduction channel is branched into three main coating agent channels, and the three coating agent discharge channels are combined again to have two main coating agent channels. It is desirable that a part of one main coating material flow path surrounded by is equivalent to a part of the coating material flow path communicating with the coating material measuring / injecting section. The cross-sectional area of the main coating agent flow path in this case means the cross-sectional area of each branched main coating material flow path.

The molding material composed of the thermoplastic resin in the present invention is not particularly limited, and a polyolefin resin,
Examples are polystyrene resin, ABS resin, AS resin, PVC resin, methacrylic resin, and fluorine-containing resin.
Not only so-called general-purpose plastics but also engineering plastics exemplified by nylon resin, saturated polyester resin, polycarbonate resin, polyacrylate resin, polyacetal resin, polysulfone resin, modified polyphenylene ether resin and the like can be used. In addition, the molding material made of thermosetting resin is not particularly limited, and includes phenol resin, furan resin, xylene / formaldehyde resin, ketone / formaldehyde resin, urea resin, melamine resin, aniline resin, alkyd resin, unsaturated polyester resin. A thermosetting resin such as an epoxy resin may be used. If desired, materials obtained by blending these molding materials with fiber reinforcement, fillers, stabilizers, pigments, etc. can also be used.

As the coating agent, oxidative polymerization type paints such as alkyd resin type, epoxy resin ester type and fatty acid modified urethane resin type, multi-liquid reaction type paints such as epoxy resin type, polyurethane type and unsaturated polyester type, alkyd resin system,
Epoxy resin-based, polyurethane-based, vinyl resin-based heat-curable coatings, epoxy acrylate oligomers, urethane acrylate oligomers, polyester acrylate oligomers, unsaturated polyesters, or radicals consisting of a mixture of two or more of these and an epoxy unsaturated monomer. Polymeric paints, or various functional paints that are made by mixing metal powders, special pigments, special additives such as UV absorbers with these paints, fluororesin lacquers, silicone resin lacquers, silane hard coat agents, etc. The various hard coating agents can be exemplified.

In the in-mold coat injecting apparatus of the present invention, a molded product can be molded by an injection molding method, a compression molding method, a reaction injection molding method, a resin transfer method or the like.

The above-mentioned objects are: (a) a coating agent flow channel through which the coating agent flows; (b) a coating for communicating with a part of the coating agent flow channel and having a tip opening into a cavity for measuring the coating agent. Agent measuring / injecting section, (c) inside the coating agent measuring / injecting section,
And a coating agent injecting means movable in the part of the coating agent flow path communicating with the coating agent measuring and injecting section, and (d) a moving means for moving the coating agent injecting means,
The tip of the coating agent injecting means obstructs the flow of the coating agent flowing in the forward end near the tip of the coating agent metering / injecting section and in the part of the coating agent channel communicating with the coating agent metering / injecting section. A molding material made of a thermoplastic resin or a thermosetting resin was molded in a cavity provided in a molding die by using an in-mold coat injecting device that can be moved by a moving means between the backward end and After that, an in-mold coating method is used in which the surface of the obtained molded product is coated with a predetermined amount of coating agent in the cavity, wherein (A) the coating agent channel is provided so that the coating agent does not stay in the coating agent channel. Molding a molding material made of thermoplastic resin or thermosetting resin in the cavity provided in the molding die, with the tip of the coating material injection means arranged at the forward end while continuing to flow the coating material inside And the process (B A step of arranging the tip of the coating agent injecting means at the backward end by the moving means, and measuring a predetermined amount of the coating agent in the coating agent measuring and injecting section; and (C) moving the tip of the coating material injecting means again. And a coating amount of the coating agent measured at the coating agent metering / injecting section on the surface of the molded article in the cavity, and the in-mold coating method of the present invention. can do.

In the in-mold coating method of the present invention, the mold clamping pressure of the mold is kept substantially the same before and after the molding material is molded in the cavity provided in the molding die, or the molding material is used. Than the clamping pressure of the mold before molding in the cavity provided in the molding die,
A mode of lowering the mold clamping pressure of the mold after molding the molding material in the cavity provided in the molding die, and further, after molding the molding material in the cavity provided in the molding die, An example is a mode in which the mold is opened by a predetermined amount.
Incidentally, these modes may be appropriately selected depending on what kind of molded product is molded.

[0028]

The in-mold coat pouring device of the present invention has a structure in which the conventional coating material measuring device and the conventional coating material pouring device are integrated. Therefore, when injecting the coating material at a high pressure, the variation of the coating material injection amount or the deterioration of the measurement accuracy due to the expansion of the pipe connecting the coating material measuring device and the coating material injection device, which is a problem in the conventional in-mold coat injecting device. Can be avoided or prevented. Moreover, in the in-mold coat injection device of the present invention, since the conventional coating material measuring device and the conventional coating material injection device are integrated, the first and fourth terms of formula (1) are eliminated, and The contribution of the third term is negligible, the desired amount of the coating material can be measured with high accuracy, and the coating material is not injected more than necessary. As a result, a film having a desired film thickness can be formed on the surface of the molded product, and further, the film thickness abnormality occurs on the surface of the molded product and the coating agent leaks from the parting surface of the mold. It can be lost.

Further, since the high pressure is applied to the coating material after the coating material injection means starts to move forward and blocks a part of the coating material flow path, it is not necessary to make the pressure resistance of the piping and the expansion of the piping expands. There is no decrease in weighing accuracy due to factors such as Furthermore, excellent workability in the implementation of the in-mold coat method. Moreover,
It is possible to increase the coating agent injection pressure and improve the accuracy of weighing when a small amount of coating agent is injected. Further, since the in-mold coat injecting device can be downsized, it is possible to downsize the mold and also cope with a small-to-medium-sized forming device.

Further, depending on the structure of the coating material flow passage, it is possible to effectively prevent the coating material retention portion from being formed in the coating material flow passage, and the cooling water chamber as in the prior art. Is not required, and the in-mold coat injecting device can be downsized and simplified.

In the in-mold coating method of the present invention, since the in-mold coating injection device of the present invention is used, it is possible to form a coating film having a precisely defined thickness on the surface of a molded product.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the accompanying drawings.

1 to 3 are schematic cross-sectional views of the in-mold coat injecting apparatus of the present invention attached to a mold of an injection molding apparatus (the whole is not shown). In addition, a schematic cross-sectional view of the in-mold coat injecting apparatus of the present invention is shown in FIG.
And shown in FIG.

The mold is a fixed mold part 10 and a movable mold part 11.
The fixed mold part 10 and the movable mold part 11 are provided with a cavity 12. The fixed mold part 10 is provided with a gate part 14 opening to the cavity 12.
Further, the fixed mold part 10 is provided with a through hole 13. During injection molding of a molded product, the molding material melted from the gate portion 14 is injected into the cavity 12.

The in-mold coat injecting device 20 is provided with a cavity 12 provided in a mold 10 or 11 of an injection molding device with a molding material made of a thermoplastic resin or a thermosetting resin.
It is a coating material metering and injecting device used in a so-called in-mold coating method for coating the surface of the obtained molded product with a predetermined amount of coating material in the cavity after molding inside.
The in-mold coat injecting device 20 is attached to the through hole 13 of the fixed mold part 10 in the mold forming the injection molding device.

The in-mold coat injection device 20 is
(A) Coating agent flow paths 21, 22, 23 through which the coating agent flows,
(B) a coating material metering / injecting portion 24 for measuring the coating material 40, which communicates with a part 21A of the coating material flow path (see FIG. 5) and has a tip portion 24A opened to the cavity 12.
(C) A coating agent injecting means 25 that is movable in the coating agent measuring / injecting section 24 and in a portion 21A of the coating agent flow path communicating with the coating agent measuring / injecting section 24, and (d) coating agent injection. And a moving means 26 for moving the means 25. The tip portion 25A of the coating material injection means 25 communicates with the coating material measurement and injection portion 24 and the forward end (see FIG. 4A) near the tip portion 24A of the coating material measurement and injection portion 24. It can be moved by the moving means 26 between the rearward travel end (see FIG. 5A) that does not obstruct the flow of the coating agent flowing in the portion 21A of the coating agent flow path. Here, the portion 21 </ b> A of the coating material channel is the portion of the coating material channel occupied by the coating material injection means 25.

As shown in detail in FIGS. 4 and 5, the coating material flow path through which the coating material 40 flows is composed of a coating material introduction flow path 22, a main coating material flow path 21, and a coating material discharge flow path 23. There is. The cross-sectional area of any part of the main coating agent flow channel is 0.5 to 2 times the cross-sectional area of the coating agent introducing flow channel, and there is no sudden change in cross-sectional shape. It is preferable for effectively preventing the coating agent retention portion from being formed therein. More specifically, (C) and (D) of FIG.
In addition, as shown in FIG. 5B, the coating agent flow passage includes one coating agent introduction passage 22 to three main coating agent passages 21B,
21C, 21D, and one coating agent discharge flow path 2 again
It has a structure that aggregates to 3. Then, one main coating agent channel 21B surrounded by two main coating agent channels 21C and 21D.
21A corresponds to a part of the coating agent flow path communicating with the coating agent measuring / injecting section 24. Coating agent channels 21, 22,
By making 23 such a structure, it is possible to prevent the coating agent from staying nonuniformly in the coating agent flow path, and to provide a cooling water chamber in the in-mold coat injection device 20 as in the prior art. It becomes unnecessary. In addition, (B), (C) of FIG.
Each of (D) and (E) is line B- of FIG.
4B is a cross-sectional view taken along line B-C-C, line D-D, and line E-E, and FIG. 4A is a cross-sectional view taken along line AA in FIG. 4B. 5B and 5C are cross-sectional views taken along lines BB and C-C in FIG. 5A, and FIG. 5A is a cross-sectional view of FIG. It is sectional drawing which followed the line AA of (B).

The coating agent measuring / injecting section 24 has a hollow cylindrical shape. Further, the coating material injection means 25 has a solid cylindrical shape and is movable in the hollow portion of the coating material measuring / injecting portion 24. The moving means 26 comprises, for example, a hydraulic cylinder.
The cross-sectional shapes of the coating agent measuring / injecting section 24 and the coating agent injecting section 25 are similar to each other in the hollow portion of the coating agent measuring / injecting section 24 and the outer shape of the coating agent injecting section 25.
As long as the coating material injection means 25 can move (slide) in 4, the shape can be any shape. The moving means 26 may be any mechanism as long as it can move the coating material injecting means 25.

The coating material supply device has a coating material tank 30, a pump 31, a check valve 32, and a branch valve 33 as in the conventional case.
And a pipe 34. The coating material 40 is supplied from the coating material supply device to the in-mold coat injection device 20, and the coating material 40 flowing out from the in-mold coat injection device 20 is returned to the coating material supply device. That is, the in-mold coat injecting device 20 and the coating material supplying device constitute a circulation system.

1 and 4 show a state before molding the molding material 50 in the cavity 12 formed in the fixed mold part 10 and the movable mold part 11 in the injection molding device. The tip portion 25A of the coating material injecting means 25 is located at the forward end near the tip portion 24A of the coating material measuring / injecting portion 24. As a result, at the time of molding the molding material, the coating agent measuring and pouring section 24
It is possible to prevent the molding material from flowing in and to prevent the coating material from flowing into the coating material measuring and pouring portion 24. The coating material 40 flows from the coating material tank 30 through the check valve 32 through the in-mold coat injection device 20 by the pump 31 until the molding material 50 is injected into the cavity 12 and the molding of the molded article is completed. ,
The coating material is returned to the coating material tank 30 via the branch valve 33 in the open state. The in-mold coat injection device 20
Inside, the coating agent flows through the coating agent introduction flow channel 22, the main coating agent flow channels 21C and 21D, and the coating agent discharge flow channel 23.
In the in-mold coat injection device 20 shown in the figure, the coating material injection means 25 is located at the forward end, and therefore the coating material is prevented from flowing in the main coating material flow passage 21B. The coating material injection means 25 may be located at the forward end, and the coating material may flow in the main coating material flow passage 21B.

In this way, the coating agent passage 2 is formed so that the coating agent does not stay in the coating agent passage, especially in the main coating agent passage 21.
While continuing to flow the coating agent inside 1, 22, 23, with the tip portion 25A of the coating agent injecting means 25 arranged at the forward end,
A molding material made of a thermoplastic resin or a thermosetting resin is molded in the cavity 12 provided in the molding die.

After the injection molding of the molding material 50 is completed, the tip end 25A of the coating material injecting means 25 is moved by the moving means 26.
Is placed at the reverse end, and a predetermined amount of coating agent is measured by the coating agent measuring / injecting section 24. This state is shown in FIGS. That is, first, the branch valve 33 is closed to stop the circulation of the coating material. Then, the moving means 26 is operated to position the coating material injecting means 25 at the backward end that does not interfere with the flow of the coating material flowing in the portion 21A of the coating material flow passage communicating with the coating material metering / injecting section 24, and the coating is performed. Tip portion 25A of agent injection means 25
To the reverse end. As a result, at the time of measuring the coating agent, the coating agent flows from the part 21A of the coating agent flow channel into the coating agent measuring / injecting section 24, and the coating agent is filled in the coating agent measuring / injecting section 24. It is measured as a predetermined amount.

Thereafter, the tip end 25A of the coating material injecting means 25 is again arranged at the forward end by the moving means 26, and the surface of the molded article in the cavity 12 is coated with a predetermined amount of the coating material metering / injecting portion 24. Coat with agent. That is, the moving means 26 is operated again to position the coating material injecting means 25 at the forward end and position the tip portion 25A of the coating material injecting means 25 at the forward end. As a result, the coating agent measuring / injecting unit 24
The coating material that has flowed in is extruded from the tip portion 24A of the coating material measuring and pouring portion 24, and the surface of the molded product is coated with a predetermined amount of coating material. Incidentally, such a state is called injection of the coating material, and the pressure applied to the coating material at this time is called injection pressure. This state is shown in FIG. Thus, the coating film 40A is formed on the surface of the molded product. After that, the branch valve 33 is opened to return the coating material to the circulating state as shown in FIG.

When the mold clamping pressure of the mold is kept substantially the same before and after the molding material is molded in the cavity provided in the mold, the pressure in the cavity is 20 MPa to
It is 100 MPa. Therefore, it is necessary to inject the coating material at such a pressure. Therefore, while the coating material injecting means 25 is moved to the forward end by the operation of the moving means 26, the pressure in the coating material in the coating material metering / injecting section 24 is equal to or higher than the pressure in the cavity. Must be added by 25. Conversely, the means of transportation 2
6 is required to have the ability to generate such pressure. However, such a high pressure is generated after the coating material injection means 25 starts to move forward and blocks the portion 21A of the coating material flow path. Therefore, high pressure is not applied to the pipe 34, and the measurement accuracy does not decrease due to expansion of the pipe 34. Also. Since normal pressure-resistant rubber piping can be used as the piping 34, workability is also excellent.

On the other hand, after the molding material is molded in the cavity provided in the molding die, the pressure after the molding material is molded in the cavity provided in the molding die is higher than the clamping pressure of the mold before molding the molding material in the cavity provided in the molding die. When the mold clamping pressure of the mold is lowered, the pressure inside the cavity drops from 40 MPa to several MPa. Alternatively, when the molding material is molded in the cavity provided in the molding die and then the mold is opened by a predetermined amount, the pressure in the cavity is reduced to about 0 MPa. In this case, the pressure applied to the coating agent in the coating agent measuring / injecting section 24 may be equal to or higher than the pressure in the cavity, and may be considerably lower than the above case. Therefore, high pressure is not applied to the pipe 34, and the pipe 34
There is no decrease in weighing accuracy due to expansion of the. Also. Piping 34
Since normal pressure-resistant rubber piping can be used for,
Excellent workability. In any case, a predetermined amount of the coating material can be measured in the coating material measuring / injecting section 24 with extremely high accuracy as compared with the conventional technique.

Further, the gap between the coating agent injecting means 25 and the coating agent measuring / injecting portion 24 surrounding it can be machined to a range of 5 to 10 μm. Therefore,
The in-mold coat injecting device 20 of the present invention is more precise than the conventional measuring cylinder, and the sealing property of the coating material is high.

The amount of coating material to be injected is defined by the volume of the hollow portion of the coating material metering / injection portion 24. Therefore,
When changing the amount of the coating agent to be injected, the volume of the hollow portion of the coating agent measuring / injecting section 24 may be changed.

(Examples and Comparative Examples) Molded articles were molded by an injection molding method, and then the in-mold coat injection apparatus of the present invention was used (Examples), and the conventional in-mold coat shown in FIG. 9 was used. The in-mold coating method was performed using an injection device (comparative example). As the injection molding device, Model: AS100B manufactured by FANUC CORPORATION was used. The shape of the cavity 12 provided in the mold is box-shaped (100 mm in length × 30 in width).
mm × depth 10 mm, wall thickness 2 mm). Injection molding was performed under the condition that the mold clamping pressure was 100 tons.
The molding material used was a thermoplastic resin (polyamide M
50% by weight of XD6 resin and 50% by weight of glass fiber). Melting cylinder temperature: 270 ° C. Injection pressure: 700 kg / cm ² Holding pressure: 800 kg / cm ² Holding time: 9 seconds

A urethane acrylate one-pack type in-mold coating material was used as a coating material, and TBPB (tert-butyl peroxybenzoate) was used as a curing agent for the in-mold coating material. In Examples and Comparative Examples, the mold clamping pressure of the mold was kept substantially the same before and after the molding material was molded in the cavity provided in the mold.

The conditions for the in-mold coating and the test results are shown in the table below. The distance from the position of the forward end of the coating material injecting means 25 to the position of the reverse end was 70 mm. Injection of coating material Coating material Coating material Coating film thickness Outer diameter of means Injection amount Injection pressure (mm) (cc) (kg / cm ² ) (mm) Example 3 0.4 700 0.1 to 0.15 5 1 750 0.2-0.3 6 2 730 0.4-0.5 Comparative example 6 0.5 35 0.4-0.5 Same as above 2 40 0.4-0.5 Same as above 10 100 0.4-0. 5 ibid 20 250 0.4 to 0.5 ibid 35 320 0.4 to 0.5 ibid 40 350 0.4 to 0.5

As is clear from the above results, when the in-mold coat injecting apparatus of the present invention was used, the film thickness became thicker as the injection amount of the coating agent increased. Therefore, the film thickness of the coating film formed on the surface of the molded product can be determined by defining the coating material injection amount. Further, the coating material injection pressure was almost constant at any coating material injection amount because the molding conditions were constant.

On the other hand, when the conventional in-mold coat injection device was used, no change was observed in the film thickness of the coating film even if the injection amount of the coating material was increased. Further, although the molding conditions were constant, the coating material injection pressure increased as the coating material injection amount increased. The phenomenon that the film thickness of the coating does not change even if the coating material injection amount is increased is
The coating material is not injected on the basis of the pressure generated by 0, but the opening / closing pin 6 in the coating material injection device 60.
It is considered that the coating material is injected based on the pressure generated by the movement of the coating material No. 3 in the coating material injection portion 62, and the pressure generated by the coating material measuring device 70 simply expands the pipe 35.

[0053]

In the in-mold coat injecting apparatus of the present invention, when injecting the coating agent at a high pressure, a pipe connecting the coating agent measuring apparatus and the coating agent injecting apparatus, which is a problem in the conventional in-mold coat injecting apparatus. It is possible to avoid or prevent the variation of the coating material injection amount or the deterioration of the measurement accuracy due to the expansion. Moreover, it is possible to measure a desired amount of the coating material with high accuracy, the coating material is not injected more than necessary, and the film thickness on the surface of the molded product is abnormal,
The problem that the coating agent leaks from the parting surface of the mold can be eliminated.

Further, it is not necessary to make the piping pressure resistant. Furthermore, excellent workability in the implementation of the in-mold coat method. Moreover, the injection pressure of the coating material can be increased, and the accuracy of the measurement when a small amount of the coating material is injected can be improved, and the in-mold coat injection device can be downsized. It can also be applied to the molding device of. If the structure of the coating agent flow path is optimized, it is not necessary to provide a cooling water chamber, and the structure of the in-mold coat injection device can be simplified.

Further, in the in-mold coating method of the present invention, since the in-mold coating injecting apparatus of the present invention is used, it is possible to form a film having a precisely defined thickness on the surface of the molded product.

[Brief description of drawings]

FIG. 1 is a schematic diagram in which an in-mold coat injection device of the present invention is attached to an injection molding device, and shows a state in which a coating material is circulating.

FIG. 2 is a schematic diagram in which the in-mold coat injecting device of the present invention is attached to an injection molding device, and shows a state in which a coating agent is measured.

FIG. 3 is a schematic diagram in which the in-mold coat injection device of the present invention is attached to an injection molding device, and shows a state in which a coating material is injected.

FIG. 4 is a schematic cross-sectional view of a part of the in-mold coat injection device of the present invention in which the coating material is circulating.

FIG. 5 is a schematic cross-sectional view of a part of the in-mold coat injecting device of the present invention in which the coating agent is being measured.

FIG. 6 is a schematic view in which a conventional in-mold coat injection device is attached to a compression molding device, and shows a state in which a coating material is circulating.

FIG. 7 is a schematic diagram in which a conventional in-mold coat injection device is attached to a compression molding device, and shows a state in which a coating material is measured.

FIG. 8 is a schematic diagram in which a conventional in-mold coat injection device is attached to a compression molding device, and shows a state in which a coating material is injected.

FIG. 9 is a schematic diagram in which a conventional in-mold coat injection device is attached to an injection molding device, and shows a state in which a coating material is circulating.

FIG. 10 is a schematic cross-sectional view of a part of a conventional in-mold coat injection device in which a coating agent is circulating.

[Explanation of symbols]

10 Fixed mold part 11 Moving mold part 12 cavities 14 Gate 20 In-mold coat injection device 21, 21A, 21B, 21C, 21D Main coating agent flow path 22 Coating agent introduction flow path 23 Coating agent discharge channel 24 Coating agent measuring and injection part 25 coating agent injection means 26 means of transportation 30 coating agent tank 31 pumps 32 check valve 33 branch valve 34, 35 piping 40 coating agent 40A coating 50 Molding material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI B29L 9:00 B29L 9:00 (72) Inventor Takeshi Fujishiro 5-6-2 Higashihachiman, Hiratsuka-shi, Kanagawa Mitsubishi Gas Chemical Co., Ltd. Plastic (72) Inventor Toshiaki Izumida 5-6, Higashi-Hachiman, Hiratsuka City, Kanagawa Prefecture Mitsubishi Gas Chemical Co., Ltd. Plastics Center (72) Inventor, Kazuyuki Akahori 5-6, Higashi-Hachiman, Hiratsuka City, Kanagawa Prefecture Mitsubishi Gas Chemicals Co., Ltd. Plastics Center (72) Inventor Yoshiaki Yamamoto 878 Nishinomon, Mitsubuchi, Komaki City, Aichi Dainichi Paint Co., Ltd. (56) Reference JP-A-59-199226 (JP, A) JP-A-4-229214 (JP, A) JP-A-62-160216 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/14 B29 C 43/20 B29C 43/34 B29C 45/46

Claims (11)

(57) [Claims] 1. A molding material made of a thermoplastic resin or a thermosetting resin is molded in a cavity provided in a molding die, and the surface of the obtained molded product is coated with a predetermined amount of the coating agent in the cavity. An in-mold coat injecting device for coating by means of: (a) a coating agent flow path through which a coating agent flows; (b) a communicating end with a part of the coating agent flow path A coating material metering / injecting section for metering the coating material, which is opened in the cavity; and (c) a coating agent flow path communicating with the coating material metering / injecting section and in the coating agent metering / injecting section. A coating material injection means movable in a part , and (d) a moving means for moving the coating material injection means,
The tip of the coating material injection means comprises a forward end near the tip of the coating material measuring / injecting portion and a coating material flowing in the part of the coating material flow path communicating with the coating material measuring / injecting portion. between a backward end that does not interfere with the flow state, and are movable by moving means, the coating agent passage is the tip of the coating agent injection means forward end
When located, stays in other parts of the coating material flow path
It has a structure in which the coating agent always flows without
A cooling device for cooling the coating agent flowing in the coating agent channel
An in-mold coat injecting device, which does not need to be provided . 2. (A) At the time of molding the molding material, the tip of the coating material injecting means is located at the forward end, thereby preventing the molding material from flowing into the coating material measuring / injecting portion. ) At the time of measuring the coating agent, the front end portion of the coating agent injection means is located at the backward movement end, so that the coating agent which has flowed into the coating agent measuring and injecting portion is measured as a predetermined amount, and (C) the surface of the molded product. Is coated with a predetermined amount of coating material, the coating material injection means is advanced to the forward end, and the coating material that has flowed into the coating material measuring and pouring portion is pushed out from the tip of the coating material measuring and pouring portion. The in-mold coat injection device according to claim 1. 3. The in-mold coat injection device according to claim 2, wherein the amount of the coating agent that has flowed into the coating agent measuring and injecting section is 0.4 liters or less. 4. The pressure applied to the coating agent by the coating agent injecting means when the coating agent is extruded from the tip of the coating agent measuring / injecting section is 100 MPa or less. The in-mold coat injection device according to item 3. 5. The coating agent flow channel is composed of a coating agent introducing flow channel, a main coating agent flow channel and a coating agent discharging flow channel, and the cross-sectional area of the main coating agent flow channel is the cross section of the coating agent introducing flow channel. The in-mold coat injecting device according to any one of claims 1 to 4, wherein the area is 0.5 to 2 times the area. 6. A coating material flow path has a structure in which one coating material introduction flow path is branched into three main coating material flow paths, and the main coating material discharge flow paths are aggregated again to form two coating materials. A part of one main coating material flow path surrounded by the coating material flow path corresponds to a part of the coating material flow path communicating with the coating material measuring and injecting section. The in-mold coat injection device according to any one of 5 above. 7. The in-mold coat injecting device according to claim 1, wherein the molded product is molded by an injection molding method. 8. A coating agent flow path through which a coating agent flows, and (b) a coating agent measuring channel for communicating with a part of the coating agent channel and having a tip opening into a cavity for measuring a coating agent. An injecting section, (c) a coating agent injecting means capable of moving in the coating agent measuring / injecting section and in a part of the coating agent flow path communicating with the coating agent measuring / injecting section , and (d) Moving means for moving the coating material injection means,
The tip of the coating material injection means comprises a forward end near the tip of the coating material measuring / injecting portion and a coating material flowing in the part of the coating material flow path communicating with the coating material measuring / injecting portion. between a backward end that does not interfere with the flow state, and are movable by moving means, the coating agent passage is the tip of the coating agent injection means forward end
When located, stays in other parts of the coating material flow path
It has a structure in which the coating agent always flows without
A cooling device for cooling the coating agent flowing in the coating agent channel
It used the in-mold coating injection apparatus and unnecessary to provide, after the molding material of a thermoplastic resin or thermosetting resin and molded in a cavity provided in the mold, the resulting molded article An in-mold coating method of coating a surface with a predetermined amount of coating agent in a cavity, wherein (A) while continuously flowing the coating agent in the coating agent channel so that the coating agent does not stay in the coating agent channel A step of molding a molding material made of a thermoplastic resin or a thermosetting resin in a cavity provided in a molding die with the tip of the coating material injection means arranged at the forward end, and (B) moving Means for arranging the front end of the coating material injecting means by the rearward end and measuring a predetermined amount of the coating material in the coating material metering / injecting section, and (C) moving the front end portion of the coating material injection means again. Placed on the edge , In-mold coating, characterized in that comprising the step, of coating the surface of the molded article in the cavity with a coating agent of a predetermined amount is weighed with a coating agent metering and injection unit. 9. The in-mold coat according to claim 8, wherein the mold clamping pressure of the mold is kept substantially the same before and after the molding material is molded in the cavity provided in the mold. Law. 10. The molding material after molding in the cavity provided in the molding die is higher than the mold clamping pressure of the mold before molding the molding material in the cavity provided in the molding die. The mold clamping pressure of the mold is reduced.
In-mold coating method described in. 11. The in-mold coating method according to claim 8, wherein after the molding material is molded in the cavity provided in the molding die, the die is opened by a predetermined amount.