JP5101310B2 - Foam molding die apparatus and foam molding body molding method using the same - Google Patents

Description

  The present invention relates to a foam molding apparatus for molding a foam molded article from expandable synthetic resin particles (hereinafter sometimes simply referred to as beads) and a method for molding a foam molded article using the same.

  The present invention is generally obtained by molding a foamed molded article from expandable synthetic resin particles by filling a foamable synthetic resin into a cavity formed by a male mold and a female mold and heating and foaming. This is normal. At that time, a filling port for filling the bead into the cavity is provided, and the bead is filled from the filling port. However, the farther from the filling port, the filling property tends to be weak, and such a part is a heating medium. Vapor such as steam tends to be weak. Such a portion has a tendency that the filling of the beads is poor and the mutual fusion of the beads is also bad, and has an important influence on the strength of the molded body.

  In particular, in the case where the foam molded body has a thin-walled molded body, or in the case of a molded body having an uneven step at the distal end of the foam molded body, a commonly used drill hole or punching slit is used. If used only (because of these restrictions, even the use of these drill holes and driving slits is extremely limited), the above tendency is remarkable due to the limited air permeability, and the filling rate of beads and mutual fusion of beads It can be assumed that the decline in sex is not negligible.

  To solve these problems, open the male and female molds widely, fill the beads with the air flow in the cavity improved, and close the male and female molds narrowly after filling. The so-called cracking is performed. Alternatively, vacuum forming or the like has been attempted in which the air in the cavity is evacuated to reduce the pressure to prevent a decrease in the filling rate of beads and the mutual fusion property of beads.

In addition to the above-described method, as disclosed in Patent Document 1, a first vent opening is provided in molding a container or lid having a step difference between a high step portion and a low step portion along the outer peripheral tip portion of the container, The first vent opening communicates with an independent passage formed between the convex shape and the concave shape and leading to the outside. Further, a second vent opening separate from the first vent opening is formed at the tip portion. A technique is disclosed in which the second ventilation opening is also communicated with the independent passage.
JP 2001-79867 A

  In the invention described in Patent Document 1, since the vent opening is provided in the step portion of the container or the lid, the filling property and the fusing property are improved. However, both the first and second vent openings need to communicate with the independent passage, and the direction in which the independent passage is provided is almost always different from the opening / closing direction of the mold. Here, in a molding machine that molds a large molded body such as a block molding machine, there is sufficient positional margin in a direction different from the opening and closing direction of the mold, so it is easy to provide an independent passage, but it is relatively small In many molding machines, installation of the independent passage is often mechanically restricted. Furthermore, the number of parts increases.

In addition, for the reason described above, the invention described in Patent Document 1 has a problem that it is difficult to modify a normal mold.

  The present invention improves the above problems.

1). A mold that obtains a foam molded article by filling foamable synthetic resin particles into a cavity formed by a male mold and a female mold each having a vapor chamber, and heat-molding using the vapor introduced into the vapor chamber. A mold apparatus for internal foam molding,
Moldings foamed molded tip which is thin-shaped, or on the occasion in a molded body having an uneven difference in level foamed molded tip,
Ventilation openings by linear slits communicating with the steam chamber are formed in the thin tip portion of the molded body or the die portion corresponding to the uneven step tip portion, between the thickness distances of the thin tip portion, or the uneven step tip portion. Between the wall thickness distances, provided substantially in parallel with the two strips, generally along the outer peripheral shape of the foam molded body,
The foam molding apparatus is characterized in that the two linear slits are provided discontinuously, and the mutual positions of the two linear slits are substantially staggered .

2 ). A mold that obtains a foam molded article by filling foamable synthetic resin particles into a cavity formed by a male mold and a female mold each having a vapor chamber, and heat-molding using the vapor introduced into the vapor chamber. A mold apparatus for internal foam molding,
When molding a molded body having a thin-walled foam molded body tip, or a molded body having an uneven step at the foam molded body tip,
Ventilation openings by linear slits communicating with the steam chamber are formed in the thin tip portion of the molded body or the die portion corresponding to the uneven step tip portion, between the thickness distances of the thin tip portion, or the uneven step tip portion. Between the wall thickness distances, provided substantially in parallel with the two strips, generally along the outer peripheral shape of the foam molded body,
And a plurality of slits for screwing the male mold mounting base and the male mold to an edge portion where the male mold mounting base and the male mold are overlapped with each other. A cutting portion that is cut in the thickness direction of the male mold mounting base leaving a fastening portion, and the cutting depth of the cutting section in the width direction of the male mold mounting base overlaps with the male mold. A first linear slit in which linear notches communicating in the thickness direction of the male mold mounting base are formed discontinuously by being deeper than the width;
A perforation is made in the thickness direction of the male mold mounting base from the back surface of the male mold mounting base, and one part of the front end of the perforation reaches a part corresponding to the convex step front end part. A foam molding die apparatus , characterized in that a discontinuous second linear slit is provided which communicates in the thickness direction of the die mounting base.

3 ). 2. The foam mold apparatus according to 2 ) , wherein the male mold mounting base is integrated with a peripheral part of the male mold.

4). Using the foam molding apparatus according to any one of 1) to 3), foamable synthetic resin particles are placed from a filling port into a cavity formed by a male mold and a female mold each having a vapor chamber. A method for molding a foamed molded product, which is filled, heat-molded with steam introduced into a steam chamber, and then cooled to obtain a foamed molded product.

  According to the present invention, modification is possible only by cutting a normally used mold mount, the aperture ratio can be increased, and no other parts are required. For this reason, not only remodeling is easy, but the volume of the mold mounting base is small even when newly manufacturing, so the heat consumption of the mold is low and the efficiency of heating and cooling is improved. As a result, the productivity is improved, and good ventilation, which is the object of the invention, can be secured at the thin-walled tip portion or the uneven-shaped stepped tip portion, and the excellent effect of improving the filling property and the fusing property is exhibited.

  In addition, since the structure is simple and the number of parts is not increased, processing is simple, manufacturing costs and remodeling costs are low, and the work such as cleaning the mold is simple, making maintenance easy and saving labor. Yes.

  The expandable synthetic resin particles used in the present invention are those obtained by impregnating synthetic resin particles with a foaming agent to give foamability. There is no particular limitation as long as the foam molding of the present invention is possible.

Examples of preferable synthetic resins used for such expandable synthetic resin particles generally include expandable synthetic resins made of polystyrene resin, polymethacrylate resin, polyolefin resin, and the like.
Of these, expandable polystyrene resins are the most common in terms of cost and characteristics and are easy to use.

  As this polystyrene-type resin, what polymerized the styrene-type monomer is used. Styrene monomers include styrene and styrene derivatives such as α-methyl styrene, paramethyl styrene, t-butyl styrene, chlorostyrene, and components that can be copolymerized with styrene, such as methyl acrylate, butyl Add one or two or more monomers such as acrylic acid and methacrylic acid esters such as acrylate, methyl methacrylate, ethyl methacrylate, cetyl methacrylate or acrylonitrile, dimethyl fumarate, ethyl fumarate Also good. Moreover, bifunctional monomers, such as bifunctional, such as divinylbenzene and alkylene glycol dimethacrylate, can be used in combination.

  Of these expandable polystyrene resins, expandable polystyrene resins are the most versatile and are preferred from the viewpoint of cost and physical properties.

  The method for polymerizing the styrenic monomer is not particularly limited, but in general, the styrene monomer is dispersed in water with a dispersant or the like, and a polymerization initiator is added to the suspension polymerization. A method of obtaining expandable styrene resin particles by impregnating with a foaming agent described later during the polymerization or after the polymerization is exemplified. Since the expandable polystyrene resin obtained by suspension polymerization or the like is generally obtained in a granular form, it is most preferable to use the expandable polystyrene resin particles obtained by this method.

  However, in the case of a styrene resin or the like obtained by general bulk polymerization or the like, it is recommended to form pellets or the like to form granules and impregnate with a foaming agent to obtain expandable polystyrene resin particles.

  The expandable polystyrene resin particles are used with or without being pre-foamed, and are the most preferable embodiment for obtaining a foamed molded article that is pre-foamed by heating with steam or the like. Generally used expandable polystyrene resin particles have a particle size of 0.2 to 4.0 mm, more preferably about 0.5 to 1.0 mm. The expansion ratio is preferably about 1.6 to 300 times, and more preferably about 15 to 60 times. The weight average molecular weight of the expandable polystyrene resin is preferably 100,000 to 500,000, more preferably about 25 to 350,000, but is not limited thereto.

  As the blowing agent, aliphatic hydrocarbons such as propane, isobutane, normal butane, isopentane, normal pentane and neopentane, which are hydrocarbons having 3 to 5 carbon atoms, are preferable. Furthermore, volatile blowing agents such as fluorinated hydrocarbons having zero ozone depletion coefficient such as difluoroethane and tetrafluoroethane can be used. Moreover, these foaming agents can also be used together. Among the expandable styrene resin particles thus obtained, the residual monomer is as low as 500 ppm or less, and the so-called low VOC resin is most preferable.

  In the present invention, the foam molded body front end means literally the foam molded body front end, and may be any foam molded body front end. In order to fill the foamable synthetic resin particles into the cavity, there are a case of normal filling and a case of filling from the side surface, but in these fillings, they exist on the side far from the filling port, that is, at the filling end. Since the effect of the present invention is more remarkably exhibited in the case of a foam molded body tip portion, a preferred embodiment is obtained. The foam molded body tip portion present at the filling end is usually present at the peripheral edge of the foam molded body.

  The vent opening by the linear slit referred to in the present invention is a slit-shaped one such as a drill hole or a driving slit that is used for introduction of steam or air circulation in a normal foaming mold. Differently, a linear gap which is a discontinuous linear notch formed in a gap between two members constituting the mold, or a part of the tip of a perforation drilled from the back surface of the mold member, A linear slit formed by reaching the other surface of the member.

  Since these linear slits can be formed in the length direction of the outer periphery of the foamed molded product, the aperture ratio is not limited by the thickness distance of the thin tip portion of the molded product or the uneven step tip portion. Can be increased, which is preferable. When these linear slits are two, it is preferable that they are provided substantially in parallel along the outer peripheral shape of the foam molded article.

  Further, a plurality of fastening portions for screwing the male mold mounting base and the male mold are left on the edge part where the male mold mounting base and the male mold are overlapped with each other. A cutting portion cut in the thickness direction of the male mold mounting base, and the cutting depth of the cutting section in the width direction of the male mold mounting base is made deeper than the overlapping width with the male mold mounting Thereby, it can be set as the 1st linear slit which is a linear notch connected to the thickness direction of this male mold mounting base.

  This linear notch is connected to the steam chamber by communicating in the thickness direction. The linear notch can also be provided at the protruding base of the fastening part of the male mold mounting base, but it was discontinuously formed by providing it at a location other than the fastening part of the male mold mounting base. It is preferable to form the first linear slit in order to ensure the strength of the fastening portion.

  Further, a perforation is made from the back surface of the male mold mounting base in the thickness direction of the male mold mounting base, and one part of the front end of the perforation reaches a part corresponding to the convex step end part. The second linear slit communicating in the thickness direction of the male mold mounting base can be formed. The perforation in this case is preferably a long hole, so that a long second linear slit can be formed.

  The first and second linear slits are preferably formed discontinuously. When these two linear slits are provided in a discontinuous manner, it is more preferable in terms of steam heating and filling uniformity that the mutual positions are substantially staggered.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing an example of a foam molding die apparatus.

  Surrounded by a moving steam chamber 4 surrounded by a male mold 1, a moving back plate 2, and a moving frame 3, and further surrounded by a female mold 5, a fixed back plate 2 ′, and a fixed frame 3 ′. An example of a foam molding die apparatus comprising a fixed-side steam chamber 4 'is shown. In this figure, the male mold 1 and the closed state are shown, and a cavity 6 is formed by both molds.

  The cavity is filled with expandable synthetic resin particles from the filling port 8 of the feeder 7, and steam is introduced into the steam chambers 4 and 4 'from the steam ports 9 and 9'. The foamable synthetic resin particles are mutually heated and melted using steam supplied from 5 fine steam holes (not shown), and then cooled to finish foam molding. Thereafter, the movable side frame 3, the movable side back plate 2 and the male mold 1 are moved backward to open the mold, and the molded body is taken out to complete the foam molding. The steam introduced into the steam chambers 4, 4 ′ is discharged from the drain ports 10, 10 ′.

  The male mold 1 is superposed on the male mold mounting base 12 with a screw 16 (see FIG. 4) such as a bolt and a nut and screwed, and is further attached to the moving frame 3 via the inner plate 11. It is done. The male mold 1 is generally attached to the moving side frame 3 via the inner plate 11 using a male mold mounting base 12 as shown in the figure, but depending on the shape of the male mold 1 May have a shape in which the male mold mounting base 12 is integrated with the edge portion of the male mold 1. In that case, in this invention, the male metal mold | die 1 and the male metal mold | die mounting base 12 are described as an integral thing.

  On the other hand, the female mold 5 is attached to the fixed side frame 3 'via the inner plate 11'.

  FIG. 1 shows the shape of the cavity 6 for molding a molded body having an uneven step at the tip of the foam molded body. In this figure, the figure about the molded body in which the front end portion of the foam molded body has a thin shape is omitted.

  FIG. 2 shows a vent opening formed by the linear slit of the present invention in a state where the male mold 1 is superposed on the male mold mounting base 12 (hereinafter, the vent opening formed by the linear slit is simply referred to as a linear slit). ) Is a plan view showing an example provided. Here, the first linear slit is indicated by A and the second linear slit is indicated by B. In FIG. 2, long hole-shaped perforations 14 are indicated by dotted lines on the back side of the second linear slit B. The first linear slit A and the second linear slit B are provided substantially in parallel with the outer peripheral shape of the foamed molded body, and the mutual positions of the linear slits A and B are staggered. In this example, the two linear slits A and B that are parallel to each other do not overlap in a direction perpendicular to the linear slits.

FIG. 3 is a cross-sectional view taken along the line Y-Y showing an overview of the male mold mount 12 and corresponds to the lower position in FIG.
A plurality of fastening portions 15 (see FIG. 4) for screwing the male mold mounting base 12 and the male mold 1 are left on the edge portion where the male mold mounting base 12 and the male mold 1 are overlapped. The cutting part 13 is cut in the thickness direction of the male mold mounting base 12. And since the cutting depth in the width direction of the male mold mounting base 12 of this cutting part 13 is deeper than the overlapping width of the male mold 1 and the male mold mounting base 12, when both are overlapped, The state which becomes the 1st linear slit A by which the linear notch connected to the thickness direction of the male metal mold mounting base 12 was formed discontinuously is shown.

  Further, a long hole-shaped perforation 14 is drilled in the thickness direction of the male mold mounting base 12 from the back surface of the male mold mounting base 12, and a portion of the front end of the perforation 14 corresponds to a convex step front end portion. The state which formed the 2nd linear slit B connected in the thickness direction of the male metal mold mounting base 12 by having reached | attained is shown.

  Since the size of these linear slits can vary greatly depending on the shape of the mold, the shape of the molded body, etc., it is difficult to specify them in general. For example, for example, the first linear slit A has a width of 0. About 1 to 0.8 mm, more preferably about 0.2 to 0.5 mm. The length is about 20 to 200 mm, preferably about 40 to 120 mm, more preferably about 60 to 110 mm.

  Examples of the second linear slit B include a width of about 0.1 to 0.8 mm, preferably about 0.2 to 0.5 mm, and more preferably about 0.2 to 0.4 mm. Further, the length of the second linear slit B is not particularly specified because there can be various cases such as the size of the mold. For example, the length is about 20 to 90% of the peripheral length of the mold mounting base. Preferably. More preferably, the length is about 30 to 85%, and most preferably the length is about 40 to 80%.

  When using perforations to form these second linear slits B, the short diameter of the perforations is, for example, about 5 to 15 mm, preferably about 7 to 12 mm, more preferably about 6 to 10 mm. .

  Since the first linear slit A and the second linear slit B communicating in the thickness direction of the male mold mounting base 12 communicate with the inside of the cavity 6 and the moving side steam chamber 4, they are far from the filling port. Since the filling performance is weak and the large opening ratio can be given to the thin-walled tip or the uneven step tip that tends to weaken the blowing of steam etc., sufficient air ventilation and steam supply can be secured, and the filling property is improved. And the effect excellent in the fusion property improvement is exhibited. In addition, the moving-side steam chamber 4 can be freely decompressed, and by taking such operations into account, it is possible to easily improve the remarkably filling property and fusion property.

  FIG. 4 is an overview diagram that makes the above explanation easier to understand, and is a perspective view that partially outlines the male mold mounting base 12 and the male mold 1 in a state where they are overlapped by screwing. The male mold mounting base 12 is provided with a cutting portion 13 that is cut in the width direction of the male mold mounting base 12 while leaving the fastening portion 15. Then, the male mold mounting base 12 and the male mold 1 are screwed and overlapped with each other by a screwing tool 16 such as a bolt or a nut. At this time, since the cutting depth of the cutting portion 13 is deeper than that of the male mold 1, the first linear slit A is formed. On the other hand, from the back surface of the male mold mounting base 12, for example, a long hole-shaped perforation 14 is drilled, and a part of the tip reaches the male mold mounting base 12 to form the second linear slit B. Is done.

It is sectional drawing which shows the outline of an example of a foaming mold apparatus. It is a top view which shows the state which the male metal mold | die piled up on the male metal mold mounting base. It is sectional drawing in the YY line which expanded the part of the male mold mounting base. The perspective view which outlines a part for showing the state where a male metallic mold mounting base and a male metallic mold are piled up by screwing together

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Male mold 2 Moving side back plate 2 'Fixed side back plate 3 Moving side frame 3' Fixed side frame 4 Moving side steam chamber 4 'Fixed side steam chamber 5 Female mold 6 Cavity 7 Feeder 8 Filling ports 9, 9 'Steam port 10, 10' Drain port 11, 11 'Inner plate 12 Male mold mounting base 13 Cutting part 14 Perforation 15 Fastening part 16 Screwing tool A First linear slit B Second linear slit

Claims (4)

A mold that obtains a foam molded article by filling foamable synthetic resin particles into a cavity formed by a male mold and a female mold each having a vapor chamber, and heat-molding using the vapor introduced into the vapor chamber. A mold apparatus for internal foam molding,
Moldings foamed molded tip which is thin-shaped, or on the occasion in a molded body having an uneven difference in level foamed molded tip,
Ventilation openings by linear slits communicating with the steam chamber are formed in the thin tip portion of the molded body or the die portion corresponding to the uneven step tip portion, between the thickness distances of the thin tip portion, or the uneven step tip portion. Between the wall thickness distances, provided substantially in parallel with the two strips, generally along the outer peripheral shape of the foam molded body,
The foam molding apparatus is characterized in that the two linear slits are provided discontinuously, and the mutual positions of the two linear slits are substantially staggered . A mold that obtains a foam molded article by filling foamable synthetic resin particles into a cavity formed by a male mold and a female mold each having a vapor chamber, and heat-molding using the vapor introduced into the vapor chamber. A mold apparatus for internal foam molding,
When molding a molded body having a thin-walled foam molded body tip, or a molded body having an uneven step at the foam molded body tip,
Ventilation openings by linear slits communicating with the steam chamber are formed in the thin tip portion of the molded body or the die portion corresponding to the uneven step tip portion, between the thickness distances of the thin tip portion, or the uneven step tip portion. Between the wall thickness distances, provided substantially in parallel with the two strips, generally along the outer peripheral shape of the foam molded body,
And a plurality of slits for screwing the male mold mounting base and the male mold to an edge portion where the male mold mounting base and the male mold are overlapped with each other. A cutting portion that is cut in the thickness direction of the male mold mounting base leaving a fastening portion, and the cutting depth of the cutting section in the width direction of the male mold mounting base overlaps with the male mold. A first linear slit in which linear notches communicating in the thickness direction of the male mold mounting base are formed discontinuously by being deeper than the width;
A perforation is made in the thickness direction of the male mold mounting base from the back surface of the male mold mounting base, and one part of the front end of the perforation reaches a part corresponding to the convex step front end part. A foam molding die apparatus , characterized in that a discontinuous second linear slit is provided which communicates in the thickness direction of the die mounting base. 3. The foam mold apparatus according to claim 2 , wherein the male mold mounting base has a structure integrated with a peripheral portion of the male mold. A foamable synthetic resin particle using a foaming mold apparatus according to any one of claims 1 to 3 from a filling port in a cavity formed by a male mold and a female mold each having a vapor chamber. A method for forming a foamed molded product is characterized in that a foamed molded product is obtained by heating and molding with steam introduced into a steam chamber and then cooling.

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