JPH10156953A - In-mold fusion bond molding method of gas-permeable and water-permeable foam resin molding and mold apparatus used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve quality stability and productivity by charging many foams made of thermoplastic resin in a predetermined partition mold, then heating in the mold to the degree that the foam is not foamed, and pressure shrinking a volume in the mold to the degree that partial surfaces of the foams are fusion bonded. SOLUTION: A male mold 1 is moved to a female mold 1a, and matched to the mold 1a to constitute a partition mold 16. Then, previously foamed foam 17 is charged in the mold 16. Thereafter, a open/close valve 9 and an interlocking open/close valve 11 are opened, hot air is supplied from a hot air supply line 8, distributed between the foams 17 group in the mold 16, melted in the vicinity of its surface without foaming, then fed to a chamber 5b of the mold 1b, and discharged out of a system. In this case, a hydraulic driver 19 is started to slowly move the mold 1b, thereby shrinking the volume in the mold 16. Thus, the respective foams 17 are urged to each other and since the surfaces are melted, the partial surfaces of the foams are fusion-bonded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The technical field of the present invention relates to a method for forming a foamed resin molded article having air permeability and water permeability.
Particularly, the present invention relates to an in-mold fusion molding method of a gas-permeable and water-permeable foamed resin molded article characterized in that a foam is formed by fusion molding without foaming in a molding die, and a molding apparatus used for realizing this molding method. About.

[0002]

[Prior art]

(A) Conventionally, as an example of a foamed resin molded article having air permeability and water permeability (or water permeability) and a method of producing the same, see JP-A-04-153026, "Ventilated and water-permeable foamed resin molded article and method of producing the same" And Japanese Unexamined Patent Publication No. 55-88949, "Foam resin model for mold". In summary, the technology disclosed by these applications is to form a compact by bonding and accumulating a partial surface of each of a plurality of granular foams using an adhesive or a binder solution. there were.

(B) As a general trial product, a foamed resin molded article having air permeability and water permeability (or water permeability) using a deformed foamed resin as a raw material can be found as a commercial product. In summary, the molding technology of these commercial products is to supply raw resin foam into the compartment mold in a state where the male and female molds to be matched are cracked (slightly open) of, for example, about 3 mm. Thereafter, the male and female molds are tightened, the latent heat of steam is passed as a heating source in the closed state, and the raw resin foam is further foamed. This was a molding method in which the surfaces of the parts were fused together, and then cooling water was supplied into the compartment mold from the outside (outside the mold) to indirectly cool and solidify.

[0004]

However, in the above-mentioned conventional example (a), there are many prior setting elements such as selection of an adhesive and the like, selection of a mixing ratio, and control of a heating temperature for bonding. Therefore, there is a disadvantage that the setup and the process management become complicated, and the addition of an adhesive or the like causes a considerable increase in cost.

[0005] In the conventional example of the above (b), the "foaming pressure (pressing pressure) by foaming in the mold" of the raw material resin foam is used.
Since the method is a method of fusing a part of the surfaces of the respective foams using the above method, the porosity required for the molded article after molding has a large variation, and the control thereof is delicate and complicated. In addition, since steam is used as a heating source, the cost of fusing increases, and condensate (adhered water) in a later step is used.
There is a problem that the removal cost is also required. Furthermore, the cooling efficiency is low because the internal compact is indirectly cooled by using cooling water in the cooling process, which inevitably increases the cycle time of all processes, lowering production efficiency and consequently lowering the cost of producing compacts. I was invited.

[0006]

Accordingly, the present invention has been made in view of the above problems, and its purpose is to adjust a molding program of a molding machine or to devise a structure of a molding die. By using a simple and inexpensive gas (mainly air) as the medium of the heating / cooling source, a new air-permeable and water-permeable foamed resin molded article with high quality stability and improved production efficiency can be obtained. An object of the present invention is to provide an internal fusion molding method and a molding apparatus used for the method.

[0007]

Means for Solving the Problems To achieve the above object, a method for in-mold fusion molding of a gas-permeable and water-permeable foamed resin molded article having a large number of communicating voids according to the present invention is constituted as follows. .

After filling a large number of foams made of a thermoplastic resin in a predetermined compartment mold, a heating step of heating the interior of the compartment mold to such an extent that the foams do not foam, A pressurizing step of pressurizing and shrinking the inner volume of the compartment mold to the extent that some surfaces are fused together, or by performing in any order in advance and molding. .

Preferably, the heating source in the heating step is a heated gas (mainly, heated air), and in the pressurizing step, the predetermined partition type is a combined type of a male type and a female type, The pressurization in the pressurizing step may be performed by moving either the male type or the female type, or both.

After the molding, a cooling step of supplying a room temperature gas (mainly, room temperature air) or a cooling gas (mainly, low temperature air) into the compartment mold may be added. To expand and describe the above step, this step is: (A) a heating step of applying hot air to each surface of a large number of foams made of a thermoplastic resin filled in a compartment mold to melt the vicinity of the surface;
(B) A pressurizing step in which the partial surfaces of the foams are completely fused with each other by a pressing force that reduces the inner volume of the compartment mold by moving the male / female mold or the like of the mold. . On this occasion,
There is a method of performing (B) after completion of (A), a method of performing (A) and (B) simultaneously in parallel, and a method of performing (A) after completion of (B), all of which are possible. However, it is effective in the order of description.

Next, a molding apparatus for realizing the above molding method is as follows.
The main configuration is used by improving a conventional general synthetic resin foam molding apparatus. That is, a partition type configured by a combination of a male type and a female type provided with a ventilation heating unit and a ventilation cooling unit, a supply unit for supplying a foam as a raw material into the partition type, In a molding apparatus comprising mold release means for releasing a molded body from a mold, it is possible to move one or both of a male mold and a female mold by a predetermined amount in a direction for further reducing the internal volume of the mold after mold matching. It is characterized by having various moving means.

In addition to the above-mentioned movement of the male / female mold, the means for contracting the inner volume of the mold includes a predetermined amount in the direction of shrinking the inner volume of the mold inside either or both of the male mold and the female mold. You may make it provide the press plate which has a breathability which can be moved. At this time, a small hydraulic pump, an encoder, or the like can be used in combination with the movement of the male / female mold or the movement of the pressing plate and the adjustment of the moving speed.

[0013] In the case of a mold apparatus in which the male / female mold is clamped and moved at the time of fusion, a mold designed to ensure a sufficient length of the parting surface (overlapping surface) of the male / female mold. Use a mold.

In order to improve the efficiency of hot air cooling and cooling of the air bubbles in the compartmental mold in the compartmental mold, for the structural material of the compartmental type, for example, a male / female mold, a highly permeable sintered metal or It may be a structure using a metal mesh or the like.

The foam used here may be a foam obtained by prefoaming a raw material bead at an appropriate expansion ratio, or may be a small-lumped foam such as a spherical product of an existing product.
Granular, square, interlocked, saddle, shibune,
An S-shaped bubble or the like may be used. Furthermore, a foam that has been formed into various shapes as a sheet, a block, a bar, or a cushioning material may be used as a small lump by means such as cutting or pulverization. That is, a so-called recycled product may be used as long as it is a foam made of a fusible thermoplastic resin, and the above-described various foams may be mixed and used.

[0016]

According to the above-described molding method, only the surface is melted without foaming due to the supplied heat, and the adjusted predetermined pressing force is applied to the foam group supplied and filled in the partition mold. Thus, some surfaces of each other are fused. As a result, a molded article of a gas-permeable / water-permeable foamed resin having a large number of voids communicating with the inside and having a predetermined shape is formed.

The pressing force (pressing force) in the pressurizing step is added when one or both of the male type and the female type move by a predetermined amount in the direction of volume contraction. In addition, male type
When the female mold is not moved, the female mold is pressed by moving the pressing plate arranged inside.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an example of a concrete molding apparatus for realizing the method for molding a ventilated / permeable foamed resin molded article according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a molding apparatus showing the present embodiment.

The mold 1 of the molding apparatus includes a female mold 1a and a male mold 1a.
The partition mold 16 is formed as a pair with the mold b, and is filled with the foam 17 as a raw material by the mold matching. The female mold 1a and the male mold 1b are provided with mating portions 3a and 3b, respectively, in which a number of small holes for ventilation are provided. Chambers 5a, 5b communicating with holes 2a, 2b
Are arranged and formed.

FIG. 6 shows that the female mold 1a is arranged on the back side,
An ejector 7 is disposed on the back side of the female die 1a, and the ejector 7 is also provided on the back side of the female die 1a. It is a feeder device for supplying a raw material foam 17 into the inside.

FIG. 8 shows a hot air supply line for supplying a heated gas (mainly high-temperature air) to the chamber 5a of the female mold 1a via the on-off valve 9. Reference numeral 10 denotes a flow from the female mold 1a to the male mold 1b. This is a hot air exhaust line for exhausting the heated gas from the chamber 5b via the interlocking on-off valve 11 interlocking with the on-off valve 9.

FIG. 12 shows a cold air supply line for supplying a cooling gas (mainly room temperature air or low-temperature air) to the chamber 5b of the male mold 1b via the on-off valve 13. The cooling gas flowing into the female mold 1a is supplied to the chamber 5a through an interlocking on-off valve 15 interlocking with the on-off valve 13.
This is a cold air exhaust line that exhausts air from

The exhaust from the hot air exhaust line 10 is
It may be supplied to the hot air supply line 8 again via a hot air generator (not shown) and recycled. Further, in the drawing, reference numeral 19 denotes a hydraulic drive device arranged and mounted on the back surface side of the frame 4b of the male mold 1b, and serves as a drive source for moving (arrow a) the direction in which the volume of the partition mold 16 is contracted. The hydraulic drive device 19 is arranged separately from a drive device for moving the male mold 1b for normal mold clamping, and moves the male mold 1b at a very low speed (arrow a) to apply a pressing force after cracking. This is done by using a small hydraulic pump. If necessary, an encoder (not shown) is arranged to control the moving amount and moving speed of the male mold 1b.

For this reason, the mating portion 3 of the female / male molds 1a and 1b
The parting surfaces (overlapping surfaces) 22 located at a and 3b are:
The design is such that a sufficient overlapping surface length is ensured so that the pressing force can be arbitrarily adjusted in the fusion process by tightening the male mold 1b, whereby the interval 23 in the thickness direction of the section mold 16 can be arbitrarily set. Can be adjusted.

As the foam 17 used here, all foams produced by foaming a thermoplastic resin can be used. For example, polystyrene, polyethylene, acrylonitrile resin, polyamide resin, fluorine resin,
A polyester resin or an ether resin is widely used.

The foam 17 has an antistatic function,
Conductive function, flame retardant function, weather resistance function, anti-mold function,
Alternatively, a material added with various functions such as a material crosslinked or colored, or a material mixed with a filler such as talc, glass fiber, or carbon fiber may be used. By using the foam body 17 having such additional functions, the molded body 18 of the present application can also enjoy these functions.

Here, the size of the foam body 17 is
Although it depends on the size of 8 or required physical properties, it can be about 0.5 mm to 50 mm, preferably 2 mm to 20 mm. In addition, the overlapping surface length of the parting surface (overlapping surface) 22 is set to a value corresponding to the interval 23 corresponding to the required thickness of the molded body 18 in consideration of cracking when the foam 17 is supplied to the partition mold 16. And [(interval 2
3) mm + (2 to 50 mm)], preferably [(interval 2
3) mm + (5 to 20 mm)], the female / male molds 1a and 1b are preferably designed.

Further, the hot air supply line 8
The temperature of the hot air supplied through the opening is controlled by the type and shape of the foam 17 to be used, and the female mold 1 through the on-off valve 9.
a (the melting temperature of the bubble 17) + (0 to 20)
0 degree C)], but preferably [(bubble 1
7) + (20-80 ° C.)]. Further, the hot air volume depends on the type and shape of the foam 17 to be used and the temperature of the hot air.
Although about 100 liters is possible, preferably 50 to 15
It is better to set the air volume to about 0 liter.

Further, normal-temperature air is usually used as the cooling gas supplied through the cold-air supply line 12, and the volume of gas supplied to the chamber 5b of the male mold 1b through the opening / closing valve 13 is determined by the amount of foam used for use. Adjustment is made in accordance with the type, shape, etc. of the 17, but about 20 to 500 liters are possible for 1 liter of the (bubble 17), but it is desirable to set the air volume to about 50 to 150 liters.

[0030]

Operation of the present embodiment With the above configuration, the present embodiment operates as follows. First, the male mold 1b is moved to the female mold 1a, and the molds are matched to form the partition mold 16. The foam 17 that has been foamed in advance in the out-of-system step (or a pulverized product of a ready-made foam) is used.
The inside of the section mold 16 is filled through the feeder device 7.

Next, the on-off valve 9 and the interlocking on-off valve 11 are opened to supply heated gas (not steam) from the hot air supply line 8. The supplied heated gas is supplied to the compartment type 16.
After flowing between the groups of bubbles 17 in the inside and melting the vicinity of the surface without foaming, it flows into the chamber 5b of the male mold 1b and is discharged from the hot air exhaust line 10 to the outside of the system.

Here, by activating the hydraulic drive device 19 and slowly moving the male mold 1b (arrow a),
The inner volume of the section mold 16 is contracted. As a result, the foams 17 are pressed together and the surfaces are melted, so that they are partially fused to each other. Then, after fusion, a room temperature air is supplied to form the air-permeable molded body 18.
By rapidly ventilating the inside, heat is removed and solidified by cooling.

As a result, a compact 18 having a large number of gaps is held ("shape-retained") between the foams 17 to form a communicating gap through which not only air but also water can pass. Will be. The size of the communicating gap can be set with a considerable degree of freedom depending on the amount of compressive force applied by the pressing force. However, at least to the extent that the shape can be maintained, the surfaces of the bubbles 17 are fused together. Need to be.

The applied compressive force is as follows. First, the foam 17 is supplied to the section mold 16 in a cracking state, and then the male mold 1b is tightened (the size of the gap 23) in the fusion step. After further tightening the male mold 1b for fusion (interval 23
), That is, [the degree of decrease in (the size of the interval 23)].

In the above-described embodiment, the foam 17 supplied to the partition mold 16 is a foamed resin foam preliminarily foamed from resin beads, and the expansion ratio is appropriately determined according to the product specifications and porosity requirements. Is selected.

Next, the molded body 18 taken out of the section mold 16 is established as a product even in this state, but it can be provided with additional functions.
For example, in order to provide water resistance as an additional function, a coating step of applying a water resistant agent so as to spread from the surface of the molded body 18 to the inside by a method using a water resistant agent spray nozzle in another step, and then blowing air Alternatively, the process may be sequentially shifted to a draining process using a means or the like, and then to a drying process using a hot-air drying furnace or the like. As a coating material having a water resistance function, for example, a styrene / butadiene paint, an acrylic paint, a vinyl acetate paint, a urethane paint, or the like is used. However, it is necessary to appropriately set the dilution ratio of the viscosity of the application material to be applied in consideration of clogging of the voids of the molded body 18.

Although the above-mentioned steps describe the application of a water-resistant agent, the present invention is not limited to this. For example, an antistatic function, a conductive function, a flame-retardant function, a weather-resistant function, a mold-proof function, etc. May be applied with a drug or coloring agent for the addition of.

[0038]

[Possibility of Other Embodiments] Next, in the above embodiment,
Although the press mold shrinkage of the inner volume of the section mold 16 is described with respect to the molding apparatus for moving the entire male mold 1b, the present invention is not limited to this, and as shown in FIG. After matching, do not move, the female mold 1a inside the male mold 1b
Alternatively, the pressing plate 24 disposed so as to cover the entire surface opposite to the above may be moved (arrow b). This pressing plate 24
Is performed by a hydraulic drive unit 25 having the same mechanism as the hydraulic drive unit 19 disposed on the back side.

In FIG. 2, the same components as those in the embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the embodiment shown in FIG. 1 and FIG.
b is moved (arrow a) or the pressing plate 24 mounted in the male mold 1b is moved (arrow b). However, this is replaced with the female mold 1a and the same operation is performed. Or even move both types together,
Or you may make it arrange | position a press plate in both types.

Further, in the above embodiment, the mold 1 of the molding apparatus is placed vertically, but it may be placed horizontally, though not shown. In the above embodiment, the supply of the heating gas is performed from the female mold 1a, while the supply of the cooling gas is performed from the male mold 1a.
b, the supply of the heating gas and the supply of the cooling gas may be alternately performed from both.

In the above embodiment, the two dies 1a, 1b
Although a pair of molds provided with a large number of small holes 2a and 2b for ventilation are provided, although not shown, both molds or at least one of the molds may be entirely or partially formed of a sintered metal or a metal. The uniformity of fusion and solidification of the foam 17 supplied to the partition mold 16 may be improved by replacing the support with a gas-permeable material such as a net.

Further, when supplying the foam 17, the mold clamping after cracking may be omitted. For example, in Example 1, after filling the foam 17 of the raw material into the partition mold 16 with the space 23 between the two dies 1a and 1b being tightened to 56 mm, the fusion process is immediately performed without tightening the space 23 to 54 mm. At the end of fusion, and set the distance 23 to 56m
m to 50 mm at once. Next, specific examples using the above molding method will be described.

[0043]

Example 1 First, HA grade polystyrene beads manufactured by Sekisui Plastics Co., Ltd. (trade name:
0.15 kg of Eslen beads, particle size about 1.8 mm)
The foamed beads were foamed with steam at a gauge pressure and cured for 24 hours to prepare foamed beads having a particle size of 7.0 to 7.5 mm and a foaming ratio of 95 times.

In the production of the molded product, PEONY-250BM, a board molding machine manufactured by Kasahara Kogyo Co., Ltd. was used. Prior to this use, an encoder for adjusting the mold clamping speed was installed on the machine, and adjustment of a molding program and the like were appropriately performed. 23 between the two dies 1a and 1b
After the above-mentioned foamed beads are filled into the partition mold 16 from the feeder device 7 in a state where
3 was tightened to 54 mm. In this state, the on-off valve 9 provided on the hot air supply line 8 and the on-off valve 11 provided on the hot air exhaust line 10 are opened almost simultaneously, and the hot air pressure before the on-off valve 9 is reduced to 0.20 kg gauge pressure. Chamber 5
a, 5b, hot air of 120 ° C.
Seconds. During this time, the interval 23 between the two dies 1a and 1b is set to 50 mm for 3 seconds from the 7th to 10th seconds of hot air passage.
Until the end of the tightening and the hot air stop were completed at the same time. Next, in this state, the on-off valve 13 provided on the normal-temperature air supply line 12 and the on-off valve 15 provided on the normal-temperature air exhaust line 14 are opened almost simultaneously, and the normal-temperature air pressure before the on-off valve 13 becomes 0.25 kg. Chamber 5 under gauge pressure
b, a normal temperature air of 25 ° C.
Seconds. After that, both molds 1a and 1b are opened,
The molded body was released from the ejector 6 and taken out.

As a result, the molded body taken out has a width of 1.
It was a rectangular body having a length of 0 m, a length of 2.0 m and a thickness of 50 mm, and had an expansion ratio of 87 times and a porosity of 31%. As for the compressive strength of the molded product, the load at which the compressed thickness was 5% was 0.5 kg / cm 2, and the load at which the compressed thickness was 10% was 0.8 kg / cm 2.

[0046]

Example 2 H of Sekisui Plastics Co., Ltd. of Example 1 above
Instead of the A grade Eslen beads foamed product, an interlocking expanded polystyrene (trade name: Aspac-Sarasara) manufactured by Asahi Kasei Corporation was used, and all other conditions were the same as in Example 1.

As a result, the removed molded body has a width of 1.
It was a square body having a length of 0 m, a length of 2.0 m and a thickness of 50 mm, and had an expansion ratio of 99 times and a porosity of 43%. The compression strength of the molded product is 0.35 kg / square centimeter when the compression thickness is 5%, and 0.45 kg when the compression thickness is 10%.
/ Square centimeter.

[0048]

According to the invention of the present application, a resin foam molded article having air permeability and water permeability by in-mold fusion can be formed without using an adhesive or the like as described above. In this molding method, since hot air and cold air are directly passed through the foam to perform molding, the molding cycle time is short, and as a result, the production cost can be reduced.

Further, since the inner volume of the mold is shrunk by physical movement of the mold or the like to generate a pressing force, and thus the partial surfaces of the foam are fused together, the completed molded body is There is an advantage that variation in porosity can be suppressed.

Furthermore, since a heating gas (mainly hot air) is used as the heating medium in the heating step instead of the generally used heating steam, that is, not the latent heat of the steam but the sensible heat of the heating gas Therefore, it is possible to achieve only uniform melting near the surface and to achieve uniform melting without foaming the foam by suppressing the amount of heat.

Further, the cooling means for cooling and solidifying or solidifying the molded body fused in the compartment mold is not an indirect cooling method using cooling water, but a cooling air in which a room-temperature air or a cold air is communicated in the space inside the molded body. The present invention has various remarkable effects, for example, the cooling time can be remarkably shortened because of the direct passage, the productivity can be increased and the molding cost can be reduced by shortening the molding cycle time. Is played.

[Brief description of the drawings]

FIG. 1 is a schematic view of a molding apparatus showing an embodiment.

FIG. 2 is a schematic view of a molding apparatus showing another example of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Die 1a Female mold 1b Male mold 2a, 2b Small hole 3a, 3b Mold joint 4a, 4b Frame 5a, 5b Chamber 6 Ejector 7 Feeder device 8 Hot air supply line 9 Open / close valve 10 Hot air exhaust line 11 Interlocking open / close valve 12 Cold air Supply line 13 On-off valve 14 Cold air exhaust line 15 Interlocking on-off valve 16 Partition type 17 Bubble body 18 Molded body 19 Hydraulic drive unit 22 Parting surface 23 Interval (of section type) 24 Press pressure plate 25 Hydraulic drive unit

Claims (6)

[Claims] 1. A method for forming a gas-permeable / water-permeable foamed resin molded article having a large number of interconnected voids, comprising the steps of: filling a plurality of foamed bodies made of a thermoplastic resin into a predetermined partition mold; A heating step of heating the inside of the compartment mold to an extent that the body does not foam, and a pressurizing step of compressing and shrinking the inside volume of the compartment mold to such an extent that some surfaces of the foams fuse together. In a mold of a gas-permeable and water-permeable foamed resin molded article, wherein the molding is carried out in parallel or in any order. 2. The method according to claim 1, wherein a heating gas is used as a heating source in the heating step. 3. The method according to claim 1, wherein the predetermined partition type is a combined type of a male type and a female type, and the pressing in the pressing step is performed by moving one or both of the male type and the female type. An in-mold fusion-molding method for the air-permeable / water-permeable foamed resin molded article according to claim 1 or 2. 4. After molding according to claim 1, 2, or 3,
A method for in-mold fusion molding of a gas-permeable and water-permeable foamed resin molded article, characterized by adding a cooling step of supplying a room temperature gas or a cooling gas into a partitioned mold. 5. A compartment type comprising a combination of a male mold and a female mold provided with a ventilation heating means and a ventilation cooling means, a supply means for supplying a foam as a raw material into the compartment type, In a molding apparatus comprising a mold releasing means for releasing a molded body from the inside of a section mold, after the molds are matched, one or both of the male mold and the female mold are moved by a predetermined amount in a direction to further reduce the volume in the mold. A molding apparatus, comprising a moving means capable of performing the following. 6. A compartment type comprising a combination of a male mold and a female mold provided with a ventilation heating means and a ventilation cooling means, a supply means for supplying a foam as a raw material into the compartment type, In a molding apparatus comprising a mold releasing means for releasing a molded body from the inside of a section mold, it is possible to move a predetermined amount in the direction of shrinking the inner volume of the mold inside either or both of the male mold and the female mold. A molding apparatus, comprising a press plate having a possible air permeability.