JP2019064173A - Foam blow molded article, foam blow molding apparatus, and foam blow molding method - Google Patents

Abstract

To provide a foam blow molded article which can be provided with layers having different functions in necessary portions without occurrence of molding defects due to foam breakage or restraint of a foam layer.SOLUTION: Provided is a foam blow molded article obtained by blow molding a foamed resin. A solid layer made of non-foamed resin is formed in an island shape outside the foamed resin layer. The foam blow molding apparatus includes an accumulator that supplies a parison made of a molten resin, and a pair of molds that sandwich and shape the parison. The accumulator is composed of a main accumulator that supplies a parison made of a molten foam resin, and a side accumulator that intermittently supplies the molten resin to the parison made of the molten foam resin and gives a layer made of the molten non-foamed resin in an island shape.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a foam blow molded article used for an air conditioning duct or the like of an automobile, and more particularly to a novel foam blow molded article in which a solid layer is partially formed for the purpose of reinforcement or the like. The present invention further relates to a foam blow molding apparatus and a foam blow molding method.

  For example, as a manufacturing method of the duct for motor vehicles for ventilating the air from an air-conditioner, the foaming blow molding which clamps and shape | molds foaming molten resin with a split mold is adopted widely. In foam blow molding, various types of ducts can be easily molded, and it is possible to mass-produce light-weight and complex-shaped ducts.

  Moreover, in the above-mentioned foam blow molding, blow molding of a hollow molded product is also performed from a multilayer parison in which resins having different functions are stacked for the purpose of functionality and appearance etc. (for example, Patent Document 1 or Patent Document 1) See literature 2 etc.).

  Patent Document 1 discloses a multilayer foam blow molding method including a skin and a foam layer, and a molded body including the skin and the foam layer is composed of an inner layer as a base material, a skin of an outer layer, and a foam layer between them. It is stated that it is done.

  Patent Document 2 discloses a method for producing an armrest by a hollow molding method, in which a part of a parison is formed into a multilayer comprising a parison base layer, the base layer and an outer layer different or different in color from the base layer. Have been described.

JP-A-6-28596438322 Japanese Examined Patent Publication 3-59814

  However, as described in Patent Document 1, when a foam resin is used inside and the entire outer side is covered to provide another resin layer (non-foamed solid layer) as a skin layer, the skin which is the outer layer in the mold Blowing pressure is applied to the foamed resin layer in a state of being sandwiched between layers, and there is a problem that the bubbles break up and the weight of the molded product increases. In the molded article including the skin and the foam layer, breaking of the cells in the foam layer is not preferable in terms of heat insulation, sound insulation, etc. in addition to weight reduction.

  In the method described in Patent Document 2, since the base layer is a non-foamed layer and the outer layer is a foamed layer, such a problem does not occur, but the base layer as a main component of the molded body is a non-foamed layer. Therefore, it is disadvantageous in weight reduction etc. In addition, even if the base layer is a foam layer and the outer layer is a non-foam layer, problems may occur in terms of formability. For example, in the method described in Patent Document 2, although the outer layer is partially formed in the circumferential direction of the parison, it is continuous in the longitudinal direction (extrusion direction) of the parison, and the base layer is in this direction. It will be restrained. This may cause problems in formability.

  The present invention has been proposed in view of such conventional circumstances, and it is possible to give a layer having a different function to a necessary part without occurrence of molding failure due to foam breakage or restraint of a foam layer. It is an object of the present invention to provide a possible foam blow molded article, and further to provide a foam blow molding apparatus and a foam blow molding method.

  In order to achieve the above-mentioned object, the foam blow molded article of the present invention is a foam blow molded article obtained by blow molding a foamed resin, and a solid layer composed of a non-foamed resin is island shaped on the outside of the foamed resin layer. It is characterized in that it is formed in

  The foam blow molding apparatus according to the present invention further includes an accumulator for supplying a parison made of a molten resin, and a pair of molds for sandwiching and shaping the parison, and the accumulator supplies a parison made of a molten foam resin. It is characterized by comprising: a main accumulator; and a side accumulator that intermittently supplies a molten resin to the parison made of the molten foamed resin and applies a layer made of the molten non-foamed resin in an island shape.

  Furthermore, the foam blow molding method of the present invention is a foam blow molding method in which a parison made of a molten resin is supplied, and the parison is sandwiched between a pair of molds to be shaped, and a parison made of a molten foam resin is supplied. At the same time, the molten resin is intermittently supplied to the parison made of the melt-foamed resin, and a layer made of the molten non-foamed resin is applied in an island shape.

  The island-shaped solid layer is not continuously extended in the longitudinal direction or the circumferential direction of the molded body (parison), and at the time of molding, the cylindrical foam parison (parison made of a molten foam resin) is not restricted. There is nothing to do. Therefore, the blowout pressure in the foamed resin layer does not cause breakage, molding failure and the like. Further, by providing the island-shaped solid layer, it is possible to reliably reinforce the necessary portions.

  According to the present invention, it is possible to provide a layer having a different function (for example, a reinforcing layer) to necessary portions without occurrence of molding failure due to foam breakage or restraint of the foam layer. As a result, it is possible to provide a lightweight, blow-molded foam of high quality in which sufficient functions are added to necessary parts.

It is a schematic perspective view which shows an example of a foaming blow molding. It is sectional drawing of the foaming blow molding shown in FIG. 1, (A) is sectional drawing in XX of FIG. 1, (B) is sectional drawing in YY of FIG. It is a schematic perspective view which shows an example applied to the air-conditioning duct. It is a figure which expands and shows the reinforcement rib formation part vicinity of an air-conditioning duct, (A) is a principal part schematic perspective view, (B) is a sectional view in A1-A1 line, (C) is a sectional view in A2-A2 line It is. It is a figure which expands and shows the flange part vicinity of an air conditioning duct, (A) is a principal part schematic perspective view, (B) is a sectional view in B1-B1 line, (C) is a sectional view in B2-B line . It is a principal part schematic perspective view which shows an example applied to the oil filler pipe. It is a schematic sectional drawing of the oil filler pipe shown in FIG. It is a figure showing typically an example of a foaming blow molding device. It is a figure which shows the structural example of an accumulator. It is a figure which shows typically the addition state of the solid layer to a parison.

  Hereinafter, embodiments of a foam blow molded article, a foam blow molding apparatus, and a foam blow molding method to which the present invention is applied will be described in detail with reference to the drawings.

  1 and 2 show an example of a foam blow molded article to which the present invention is applied. The foam blow molded article 1 of the present embodiment is mainly made of a cylindrical foam molded article main body 11, and an island-shaped solid layer 12 is formed on the surface thereof.

Here, the foam molded body 11 is molded by, for example, blow molding a thermoplastic resin mixed with a foaming agent. As a thermoplastic resin to be used, although it is arbitrary, a polypropylene resin etc. can be mentioned, for example, and 1 to 20 mass% polyolefin polymer and 5 to 40 mass% hydrogenated styrene thermoplastic elastomer are mixed. Blended resin etc. can also be used. In particular, in order to improve the foamability, it is desirable to add a long chain branched polyolefin as a resin material. Specific examples of the long chain branched polyolefin include, for example, component A, component B and component C, the component A is long chain branched homopolypropylene, and the component B is block polypropylene (long Although it may have a chain branched structure, it is not limited thereto), and the component C is a resin for foam molding or the like which is a polyethylene-based elastomer. Preferably, when the total of the components A to C is 100 parts by mass, the content of the component A is 20 to 70 parts by mass, the content of the component B is 20 to 70 parts by mass, and the components The content of C is 1 to 20 parts by mass. Alternatively, a resin in which high density polyethylene and low density polyethylene having a long chain branched structure are mixed may be used.

  Blowing agents include physical blowing agents, chemical blowing agents and mixtures thereof. As physical foaming agents, inorganic physical foaming agents such as air, carbon dioxide gas, nitrogen gas, water and the like, organic physical foaming agents such as butane, pentane, hexane, dichloromethane, dichloroethane and the like, and their supercritical fluids Can be applied. As a supercritical fluid, it is preferable to use carbon dioxide, nitrogen, etc., and if it is nitrogen, its critical temperature is -149.1 ° C, its critical pressure is 3.4 MPa or more, and if it is carbon dioxide, its critical temperature is 31 ° C, its critical pressure It can produce by setting it as 7.4 Mpa or more.

  The expansion ratio of the foam molded body 11 formed by blow molding is arbitrary, and is configured by a closed cell structure (having a closed cell ratio of, for example, 70% or more) having a plurality of cell cells. The average cell diameter of the cells in the thickness direction is, for example, less than 300 μm, preferably less than 100 μm.

  An advantage of the foamed resin used for the foam molded body 11 is that the specific gravity and the heat conduction are low. Taking advantage of these advantages, it has been adopted in various molded products for weight reduction and high heat insulation effect. On the other hand, the foamed resin has low mechanical strength and can not be used at the site where the load is applied.

  Therefore, in the foam blow molded article 1 of the present embodiment, the solid layer 12 is provided in a portion where strength is required in the foam molded article main body 11. The solid layer 12 is a resin layer made of non-foamed resin, and has sufficient mechanical strength as compared with the foamed resin.

  Although the resin material used for the solid layer 12 is optional, it is not necessary to add a long chain branched polyolefin as in the foam molded body 11, and the polyolefin which does not have a cheaper long chain branched structure due to manufacturing costs. It is desirable to use

  The foam molded body 11 and the solid layer 12 are preferably formed of the same material. For example, when the foam molded body 11 is formed of long chain branched polypropylene, it is desirable that the solid layer 12 be polypropylene. Alternatively, when the foam molded body 11 is formed of long chain branched polyethylene, it is desirable that the solid layer 12 be polyethylene. By using the same kind of material for the foam molded body 11 and the solid layer 12, the adhesion between the foam molded body 11 and the solid layer 12 is improved, and the melting point of the resin becomes equal. The adjustment of the resin heating temperature in the above becomes easy, and the timing at which the molten resin is cooled and solidified by the mold can be matched, so that deformation of the molded product and the like can be suppressed.

  However, when the solid layer 12 is continuously provided on the surface of the foam molded body 11, the solid layer 12 restrains the foam molded body 11, thereby preventing the foam formation, breaking the foam, or adversely affecting the formability. There is a risk of giving. Therefore, in the blow-molded foam 1 of the present embodiment, the solid layer 12 is island-shaped (here, rectangular) to prevent such a problem from occurring. In addition, island shape means the state which is not extended continuously in any of the longitudinal direction of the foaming molding main body 11, and the circumferential direction. As shown in FIGS. 2A and 2B, the solid layer 12 is formed to have a predetermined dimension in any of the circumferential direction and the longitudinal direction of the foam molded body 11 and is continuously extended. Absent.

  The foam blow molded article 1 having such a configuration has a large part (foam molded article main body 2) composed of a single layer of the foamed resin layer, so that the light weight effect is maintained. In addition, although the solid layer 12 is applied to necessary portions to form a partial multilayer structure, mechanical strength can be significantly improved in the portion where the solid layer 12 is formed, compared to the surrounding.

  FIG. 3 shows an example of the duct 2 to which the present invention is applied. As shown in FIG. 3, the duct 2 is mainly made of a tubular molded body 21 serving as a flow path of air, and an opening for connecting to another duct or the like, an opening for serving as a blowout, etc. The opening 22 of the The molded body 21 which is the main body of the duct 2 is formed of a foamed resin for weight reduction, soundproofing and the like, but the strength is insufficient at a portion affected by an external force. Therefore, a solid layer is formed in an island shape at the portion concerned to increase the strength of this portion.

  Specifically, in the duct 2, a rib 23 for improving strength is formed, and a flange portion 24 for external attachment is formed. The portion where the rib 23 and the flange portion 24 are formed is a portion in the duct 2 in which the strength is particularly required. Therefore, in the present embodiment, the solid layer 25 is formed in the vicinity of the rib 23 and the flange portion 24.

  FIG. 4 shows the vicinity of the rib 23 formed in the duct 2. The rib 23 is formed by recessing the upper surface of the tubular molded body 21, and the mechanical strength is improved by the end surface of the rib 23 being in contact with the opposite inner wall surface. As shown in FIGS. 4A to 4C, the solid layer 25 is formed to be laminated on the surface of the rib 23 and the periphery thereof.

  Further, FIG. 5 shows the flange portion 24 formed in the duct 2. As shown in FIG. 5A, the flange portion 24 is formed so as to project from the molded body 21 by compressing the foamed resin when molding the molded body 21, and by mounting and fixing the same, the duct portion 24 is formed. 2 is fixed. Therefore, mechanical strength is required for this flange portion 24 as well. Therefore, as shown in FIGS. 5A to 5C, the solid layer 25 is formed so as to cover the surface of the flange portion 24.

  In the duct 2, although the solid layer 25 is provided as a reinforcement of the portion affected by the external force, for example, the solid layer is provided on the screw cap portion of the oil filler pipe to improve the rotational torque of the cap Also, the shape transferability of the screw portion can be improved.

  6 and 7 show the vicinity of the screw cap portion of the oil filler pipe 26. FIG. The oil filler pipe 26 is composed of a pipe body 27 and a screw cap portion 28 formed at the tip thereof. A screw thread is formed in the screw cap portion 28, and as described above, improvement in rotational torque of the cap, improvement in shape transferability of the screw portion, and the like are required. Therefore, in the oil filler pipe 26 of the present embodiment, the solid layer 29 is provided on the surface of the screw cap portion 28 to partially multilayer. In the present embodiment, the solid layer 29 is continuous in the circumferential direction of the screw cap portion 28. However, when viewed in the entire molded body (entire oil filler pipe 26), it is formed in an island shape.

  In addition, it is useful to form a solid layer in island shape also in a product to which load is applied locally like a foot duct.

  Next, a molding apparatus and a molding method for the foam blow molded article having the above-described configuration will be described.

  In foam molding of an extrusion resin such as blow molding, since the bubbles grow at the moment when the pressure around the resin drops sharply, it is necessary to maintain the pressure in the resin flow path just before the injection of the molten resin. Therefore, in foam extrusion molding, multi-layering is considered to be difficult.

  In addition, although multi-layer foam molding by sheet has already been adopted in many fields, in the manufacturing method, since it is necessary to hold the sheet outside the cavity of the mold, the outer layer always crosses the sheet in the molding The effect of weight reduction can not be obtained sufficiently. The variation in the location of the outer layer also increases. Furthermore, sheet forming can not be recycled in the process because of its manufacturing method.

  Alternatively, for example, a method of attaching urethane to a blow-molded article is also adopted, but removal and separation are necessary at the time of recycling, leading to loss of members and manufacturing tact.

  In the apparatus and method for molding a blow-molded foam according to the present invention, molding in which a solid layer is partially formed is realized by using the ring accumulator and the second extruder in combination.

  FIG. 8 shows a schematic configuration of the foam blow molding apparatus, which basically comprises an extruder (accumulator) 31 and a pair of molds 32 and 33 for shaping the same. At the time of molding, a parison P made of a molten resin extruded from the extruder 31 is sandwiched between a pair of molds 32 and 33 for shaping, and this is taken out from the molds 32 and 33 to obtain a foam blow molded article.

  Here, as shown in FIG. 9, the extruder 31 includes a main accumulator 40 for supplying a molten foam resin, and a side accumulator 50 for adding a molten resin for forming a solid layer from the side to a parison P. .

  The main accumulator 40 is configured to have an annular die 41 and a core 42 disposed at the center thereof, and the molten resin passes through an annular slit 43 between the die 41 and the core 42 to form a circle. The annular parison P is pushed out. Here, the thickness of the parison can be adjusted by adjusting the distance between the die 41 and the annular slit 43 between the core 42.

  The side accumulator 50 is provided with an extruder 51 for supplying a molten resin for forming a solid layer, and the resin introduced from the inlet 52 is melt-kneaded in a cylinder 53 provided with a screw, and the side accumulator 50 is Supplied to In the side accumulator 50, the molten resin for solid layer formation is intermittently applied to the surface of the parison P.

  FIG. 10 schematically shows how the solid layer forming resin S is applied to the parison P. As shown in FIG. By intermittently supplying the solid layer forming resin S from the side accumulator 50, the solid layer can be formed on the surface of the parison P in a state in which it is not continuous in either the circumferential direction or the extrusion direction (longitudinal direction) of the parison P The resin S can be applied in an island shape. By molding the parison P to which the resin S for forming an island-like solid layer has been applied on the surface with the molds 32, 33, it is possible to form a foamed blow molded article in which the island-like solid layer is formed. it can.

  In the above-described apparatus and method for molding a blow-molded foam, it is possible to pinpoint only the portion to which a function is desired to be imparted, and to suppress foam breakage, foaming failure and the like in the foamed resin which is a substrate. In addition, it is possible to reduce the weight as compared to a multi-layered molded body as a whole. Furthermore, manufacturing costs can be suppressed compared with the molded object made into the multilayer which made the whole or the circumferential direction or a longitudinal direction continuously by making it multilayer only in the part to which a function is desired to be provided.

  Furthermore, the apparatus and method for forming a foam blow molded article according to the present invention have the advantages that recycling in the manufacturing process is possible and that sorting is not necessary.

  Although the embodiments to which the present invention is applied have been described above, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the scope of the present invention. It is possible.

Reference Signs List 1 foam blow molded body 11 foam molded body main body 12 solid layer 2 duct 21 molded body 22 opening 23 rib 24 flange portion 25 solid layer 26 oil filler pipe 27 pipe body 28 screw cap portion 29 solid layer 31 extruder 40 main accumulator 41 Die 42 Core 43 Annular slit 50 Side accumulator 51 Extruder 52 Input port 53 Cylinder P Parison S Resin for solid layer formation

Claims (4)

  What is claimed is: 1. A blow-molded foam, which is obtained by blow molding a foamed resin, wherein a solid layer made of a non-foamed resin is formed in an island shape on the outer side of the foam resin layer.   The foam blow molded article according to claim 1, wherein the foam blow molded article is a duct, and the solid layer is provided for reinforcement. An accumulator for supplying a parison made of a molten resin, and a pair of molds for sandwiching and shaping the parison,
The accumulator is a main accumulator for supplying a parison made of a molten foam resin, and a molten resin is intermittently supplied to the parison made of the molten foam resin, and a layer made of a molten non-foamed resin is applied in an island shape. What is claimed is: 1. A foam blow molding apparatus comprising: an accumulator; A foam blow molding method which supplies a parison made of a molten resin and sandwiches the parison between a pair of molds to form the parison.
A foam blow characterized in that a parison made of a molten foam resin is supplied, and the molten resin is intermittently supplied to the parison made of the melt foam resin, and a layer made of the molten non-foam resin is applied in an island shape. Molding method.

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