JP2007230168A - Manufacturing method of foamed resin molded product and foamed resin molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a manufacturing efficiency for a foamed resin molded product excellent in acoustic absorption property. <P>SOLUTION: A manufacturing method of the foamed resin molded product comprises arranging general faces 23 and 33 at molding faces 21 and 31 of at least one of molds 20 and 30 and a temperature up section 24 to be higher temperature than the general face and forming the foamed resin molded product M10 under forming a skin layer M16 not foamed on the surface contacted with the general faces 23 and 33 by separating the molds 20 and 30 and forming an air vent hole M16a on the surface adjacent to the temperature up section 24. Further a heat insulating material (a heat insulating structure) 26 which thermally insulates the general faces 23 and 33 and the temperature up section 24 may be formed on at least one of the molding faces 21 and 31 of molds 20 and 30. The temperature up section 24 can be formed into a shape to be more projected to a cavity C1 than the general faces 23 and 33. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a resin foam molded article used for automobile interior materials and the like, and a resin foam molded article.

Conventionally, a foamed resin molding material is injection-molded by separating (core back) a pair of molding dies as described below and used as an automobile interior material.
First, a resin molding material containing a foaming agent is heated and melted and filled in a cavity formed by clamping a male and female mold, and after a predetermined number of seconds, the male and female molds are placed at a predetermined distance from each other. The cavity volume is expanded by being spaced apart by a distance. Then, the resin molding material filled in the cavity is released from the internal pressure, and the foaming agent contained therein expands to follow the cavity and expand. Thereafter, the resin molding material is solidified in a state having a large number of bubbles to form a resin foam molding.
The resin foam molded body has a structure having a skin layer on the surface formed by cooling in contact with a mold at an early stage of molding, and a foam layer formed along with foaming of the foaming agent inside the skin layer. Has been. The obtained resin foam molded article is lightweight and soft to the touch, and has applications in automobile interior panels and the like. In addition, there is a reasonable advantage that the molding process is completed in one step.
JP-A-2005-59224 JP 2002-317548 A

  However, it has not been possible to efficiently produce a resin foam molded article that provides good sound absorption as an automobile interior material.

Patent Document 1 describes a thermoplastic resin foam molded article containing at least three types of layers in this order: a skin layer, a low foam layer, and a high foam layer. In paragraph 0015 of the same document, for the enlarged photograph of the high foam layer part, an area corresponding to 0.5 mm square of the part in contact with the low foam layer is taken, and the bubbles contained in this area and most of them are 0.5 mm square. It is described that the bubbles contained in the region are obtained by measuring the diameter (Da1) in the thickness direction and the diameter (Da2) in the direction perpendicular to the thickness direction and calculating the number average value.
The thermoplastic resin foamed molded article has a diameter Da1, Da2 obtained from bubbles contained in a 0.5 mm square region, and has a large number of small bubbles with a maximum long diameter of about 0.5 mm. For this reason, there is no air permeability inside the foam molded article, and it cannot be said that the tactile sensation as an automobile interior material is good, and it cannot be said that the sound absorption is high.

Patent Document 2 describes an impact-absorbing floor material including a cushion layer and a surface layer made of a polyolefin foam in which inner cells extend in a spindle shape in the thickness direction.
The shock absorbing flooring also has an average aspect ratio of 1.1 to 4, which is smaller than the thermoplastic resin foam molded article described in Patent Document 1, and therefore there are very elongated cells whose maximum major axis reaches 1 mm. do not do. In addition, as shown in FIG. 1B, since the cells do not communicate with each other, there is no air permeability inside the flooring, and it cannot be said that the tactile sensation as an interior material is good, and the sound absorption is also good. It was not expensive.

  An object of this invention is to improve the manufacturing efficiency of a resin foam molded object with favorable sound-absorbing property.

In order to achieve the above-mentioned object, the present invention fills a cavity formed when a pair of molds capable of approaching and separating from each other are brought close to a predetermined proximity position with a resin molding material containing a foaming agent, and then A method for producing a resin foam molded article in which a pair of molds are separated to a predetermined separation position and the cavity is expanded to form foam cells in the resin molding material in the cavity to mold a resin foam molded article. In addition, at least one molding surface of the mold is provided with at least a general surface and a temperature raising portion having a temperature higher than the general surface, and the pair of molds are separated from each other so that the surface in contact with the general surface is non-foamed. The resin foam molded article is formed by forming an opening in the surface in contact with the temperature raising portion while forming the skin layer.
Further, the resin foam molded body of the present invention has an opening on the surface in contact with the temperature raising portion while forming a non-foamed skin layer on the surface in contact with the general surface by separating the pair of molds. It is formed and molded.

When a pair of molds forming a cavity filled with a resin molding material are separated from each other, the surface of the resin molding material in contact with the general surface of the mold is cooled to form a non-foamed skin layer. Openings are formed on the surface of the resin molding material in contact with the high temperature heating portion. Thereby, it is not necessary to form an opening on the surface of the resin foam molded body by post-processing, and an opening is formed on the surface of the resin foam molded body simultaneously with molding. Here, the sound toward the resin foam molded article enters the opening of the resin foam molded article and is absorbed. Therefore, a resin foam molded article having good sound absorbing properties can be obtained simultaneously with molding, and the production efficiency of the resin foam molded article having good sound absorbing properties is improved.
If the concave and convex portions are provided on the molding surface of the molding die without changing the temperature, the temperature at the internal position corresponding to the concave portion of the molding surface in the resin molding material filled in the cavity is increased. As a result of the temperature becoming higher than the temperature at the internal position corresponding to, a cavity is formed inside the resin foam molded body. However, a skin layer is formed on the surface in contact with the concave portion and on the surface in contact with the convex portion. In the present invention, since a hole is forcibly formed on the surface in contact with the temperature rising portion at the same time as the separation of the mold, a good sound-absorbing resin foam molded body can be obtained simultaneously with the molding, and the production efficiency is improved. .

The temperature raising part may be provided only on one of the pair of molds or on both molds. If a plurality of the temperature raising portions are provided in the mold, the ratio of the sound waves going to the resin foam molded body to enter the openings increases, so that the sound absorption of the resin foam molded body is improved. Each temperature raising unit may be an independent member or a part of a mold, and may be composed of a single member or a plurality of members.
When the temperature rising part is insulated from the general surface with a heat insulating structure, the heat transfer from the temperature rising part to the general surface is suppressed, so that the temperature rising part is maintained at a high temperature and stably opened in the resin foam molded body. Is formed. Of course, the temperature raising portion may be provided in contact with a general surface, and in this case, a heat insulating material or the like can be used for the temperature raising portion.
The temperature raising unit may be flush with the general surface, but may have a shape protruding toward the cavity from the general surface. Then, the opening is more reliably formed in the resin foam molded body.
The temperature raising unit may be fixed in position or movable.
The temperature raising unit may be heated to a temperature higher than the general surface by a heating mechanism. Then, the temperature raising portion is stably maintained at a high temperature, and the openings are stably formed in the resin foam molded body. Of course, even if the temperature raising portion is not heated by the heating mechanism, heat is supplied from the high-temperature resin molding material and the temperature rises, so that an opening is formed in the resin foam molded body.
The term “temperature rise” means that the temperature rises, and may mean that the temperature is positively increased by a heating mechanism or the like, or it means that the temperature rises naturally due to the heat of the high-temperature resin molding material without using the heating mechanism. Good.

The general surface may be cooled to a temperature lower than the melting point of the resin molding material by a cooling mechanism. Then, the general surface is stably maintained at a lower temperature than the temperature raising portion, and the skin layer is stably formed on the resin foam molded article. Of course, even if the general surface is not cooled by the cooling mechanism, the temperature becomes lower than the temperature raising portion when the mold is cooled by the outside air, so that a skin layer is formed on the resin foam molded body.
The molding surface of the mold may be provided with only the general surface and the temperature raising part, or a structure other than the general surface and the temperature raising part, such as a heat insulating structure that insulates the general surface and the temperature raising part. Also good.
In addition, the resin foam molded body may be molded using a cooling mechanism for cooling the general surface, a heating mechanism for heating the temperature raising portion, a slide drive mechanism for slidingly driving the temperature raising portion, or the like.
Each case described above is also included in the claims.

According to the invention which concerns on Claim 1, it becomes possible to improve the manufacture efficiency of a resin foam molded object with favorable sound absorption property.
In the invention which concerns on Claim 2, since the sound which goes to a resin foam molded object approachs into a cavity from an opening and is absorbed, it becomes possible to improve the sound absorption property of the resin foam molded object manufactured.
In the inventions according to claim 3, claim 4, claim 6, and claim 7, it is possible to more reliably form holes on the surface of the resin foam molded article, and to improve the sound absorption of the resin foam molded article to be manufactured. Further improvement is possible.

In the invention which concerns on Claim 5, an opening can be more reliably formed in the surface of a resin foam molded object, and it becomes possible to further improve the sound absorption property of the resin foam molded object manufactured.
In the invention according to claim 8, since the temperature raising portion slides toward the cavity simultaneously with the separation of the molding die to form the opening in the surface of the resin molding material, the production of the resin foam molding having the opening in the surface Efficiency can be improved.

In the invention according to the ninth aspect, it is possible to obtain a resin foam molded body having an opening having a more stable shape on the surface.
In the invention which concerns on Claim 10, it becomes possible to obtain the resin foam molding with favorable sound absorption property with favorable manufacturing efficiency.

Hereinafter, embodiments of the present invention will be described in the following order.
(1) Manufacturing method of resin foam molding:
(2) Modification:

(1) Manufacturing method of resin foam molding:
FIG. 1 is a diagram schematically illustrating a method for manufacturing a resin foam molded body M10 according to an embodiment of the present invention, and FIG. 2 is a diagram schematically illustrating a resin foam molded body manufacturing apparatus 10 used in the present manufacturing method. FIG. 3 is an exploded perspective view showing a state in which the heat insulating material 26 and the temperature raising member 24 are attached to the mold 20, and FIG. 4 shows the main parts of the molds 20, 30 that form the cavity C 1 when in the predetermined proximity position L 1. FIG. 5 is a timing chart showing the amount of movement of the molding die 20, FIG. 6 is a figure showing the structure of the general part M10a of the resin foam molding in a vertical section, and FIG. 8 is a cross-sectional view showing a change in the resin molding material M1, FIG. 8 is a diagram showing a partial plane and vertical cross section of the resin foam molded body M10 according to an embodiment of the present invention, and FIG. 9 is an application of the resin foam molded body M10. The perspective view which shows the external appearance of the interior material for automobiles A.
This resin foam molding M10 is used for automobile interior materials such as sound absorbing panels.

In this manufacturing method, the resin molding material M1 containing a foaming agent is filled into the cavity C1 formed when a pair of molds 20 and 30 that can approach and separate from each other are brought close to a predetermined proximity position L1, and then the above-mentioned The pair of molds 20 and 30 are separated (core back) to a predetermined separation position L2 to expand the cavity C1, thereby forming a frost column-shaped foam cell M13 in the resin molding material in the expanded cavity C1. Resin foam molding M10 is molded. The molded body M10 is formed in a thin and wide shape such as a flat plate shape, a curved plate shape, a sheet shape, and the surface of the molded body may have various shapes such as a planar shape, a curved surface shape, and an uneven shape. it can.
Here, the distance d1 between the pair of molding dies 20 and 30 at the proximity position L1 is set to 1.0 to 10.0 mm. When the distance d1 is greater than or equal to the lower limit, the foamed cells are not cut in the middle of the thickness direction (separating direction D1), and the frost columnar foamed cells are sufficiently long in the thickness direction to increase the internal air permeability, thereby providing good sound absorption. The obtained interior material is preferable in terms of obtaining good elasticity and good tactile sensation, and if the distance d1 is set to the upper limit or less, the resin foam molded body does not become too hard and the frost columnar foam cell becomes sufficiently long in the thickness direction and the inside. This is because it is preferable in that good air-absorbing property can be obtained and good elasticity and good tactile sensation can be obtained. Further, the separation distance (core back distance) d2 from the proximity position L1 to the separation position L2 is 1.0 to 50.0 mm, and more preferably 4.0 to 20.0 mm. When the distance d2 is set to the lower limit or more, the foam cell is sufficiently long as 1.0 mm or more in the separation direction D1, and it is preferable in that good sound absorption can be obtained by increasing the air permeability of the frost columnar foam cell portion. If d2 is less than or equal to the upper limit, the foamed cells are not cut in the thickness direction, which is preferable in that good elasticity and good tactile sensation can be obtained as an interior material. The thickness d3 of the resin foam molded body M10 is d1 + d2. In this manufacturing method, while forming the non-foamed skin layer M16 on the surface, the bubbles are continuously arranged in the separation direction D1 of the pair of molds 20 and 30 so as to be 1.0 mm or more within the range of the separation distance d2 or less. The foamed cell M13 is elongated in the form of a frost column, and the resin foam molded body M10 is molded.
Here, at least one of the molding surfaces 21 and 31 of the molds 20 and 30 is provided with at least a general surface (23) and a temperature raising portion (24) that is higher in temperature than the general surface. And this manufacturing method is the surface which contacted the temperature rising part 24, forming the non-foamed skin layer M16 in the surface (general surface M10b) which contacted the general surface 23 by separating a pair of shaping | molding die 20 and 30. Vent holes (open holes) are formed in the resin foam molded body M10.

As a molding apparatus suitable for molding the resin foam molded body, a known in-line screw type injection molding machine can be used, and the form (solid type, horizontal type) or drive system (hydraulic type, electric type, etc.) ) Does not matter.
FIG. 2 shows an example of a foam injection molding machine for molding the resin foam molding. The foam injection molding machine 10 includes a molding material charging hopper 13, a gas storage tank 14, a cylindrical outer cylinder member 15 centering on the extrusion direction of the resin molding material, a screw 16 inserted into the outer cylinder member, an outer cylinder member 15 is provided with a gas injection device 17 attached in the middle of 15, a motor (not shown) that rotationally drives the screw 16, a moving mold 20 that is a male mold, a fixed mold 30 that is a female mold, a cooling mechanism 40, and the like. The main parts of ˜16, 20, and 30 are made of metal. The L / D ratio of the screw 16 can be set to about 20, for example. The molding dies 20 and 30 attached to the tip of the outer cylinder member 15 are male and female molds, and form a required cavity C1 sealed in a clamped state. For example, the gas injection device 17 controls the injection pressure of the inert gas to a constant pressure.
The foam injection molding machine 10 injects a liquid (including a molten state) resin molding material from the injection port 15a into the cavity C1, and separates the male mold 20 from the female mold 30 to a predetermined separation position, thereby resin in the cavity C1. By foaming the molding material and solidifying or curing the resin molding material, the resin foam injection molded body M10 is formed. Then, by opening the molds 20 and 30 and taking out the molded body M10, one cycle of manufacturing the resin foam injection molded body is completed.
The movable mold 20 may be a female mold, and the fixed mold 30 may be a male mold. In addition to enabling only the molding die 20 to slide, the molding die 30 formed with the injection port may be slidable, or only the molding die 30 may be slidable. Furthermore, a mold using a slide core may be used as the mold 20.

As shown in FIG. 4, the movable mold 20 is provided with a general part 22, a temperature raising member (temperature raising part) 24, and a heat insulating material (heat insulating structure) 26. The molding surface 21 of the movable mold 20 is provided with a general surface 23 of the general portion, a body portion 24a of the temperature raising member 24, and a cavity side surface 26c of the heat insulating material 26. The fixed mold 30 includes only a general part 32. Of course, as shown in FIG. 10, the fixed mold 30 may be provided with the temperature raising part 24 and the heat insulating structure 26, or the fixed mold may be provided with the temperature rising part and the heat insulating structure.
The material of the movable general part 22 and the fixed mold 30 may be S50C steel (47 W / m / K), S50C steel (59 W / m / K), SKD61 steel (43 W / m / K), or the like. For example, a material having a thermal conductivity of 40 to 400 W / m / K can be used.
As shown in FIG. 3, a substantially frustoconical heat insulating material attachment hole 21 a for inserting and attaching the heat insulating material 26 is formed on the movable molding surface 21 according to the number of the temperature raising members 24. .

As the material of the temperature raising member 24 constituting the temperature raising portion, a material having a high thermal conductivity such as a metal such as aluminum or copper can be used. For example, a material having a thermal conductivity of 200 to 400 W / m / K is used. Can be used. The dispersion density of the temperature raising member 24 when a plurality of the temperature raising members 24 is provided affects the density of the air holes formed in the resin foam molded body, and is determined by the dispersion density of the air holes necessary for the resin foam molded body. it can be set to 3.0 pieces / cm ^2. The temperature raising member 24 is composed of a main body portion 24a protruding to the cavity side and a root portion 24b embedded in the heat insulating material 26, and is roughly formed in a stepped columnar shape. The main body portion 24a is formed in a substantially cylindrical shape and has a shape in which a corner portion of the column is chamfered. The root portion 24b is formed in a substantially cylindrical shape that is thinner than the main body portion 24a, and has a shape in which a corner portion of the column is chamfered. Of course, various shapes such as a non-chamfered columnar shape, a sharpened tip, and a tapered shape are conceivable as the shape of the main body and the root.
In addition, although the corner | angular part by the side of the root part in the main-body part 24a is made into the chamfered taper shape called an undercut shape, even if it has such a taper shape, the shape | molded resin foam molded object is extracted from a type | mold. be able to. Of course, the main body portion of the temperature raising member may not be undercut, or the undercut portion of the main body portion may be embedded in the heat insulating material.
The diameter d11 of the main body portion 24a affects the diameter of the ventilation hole (opening) M16a formed in the resin foam molded body, and consequently the sound absorption characteristics of the resin foam molded body. From the viewpoint, for example, the thickness may be 0.5 to 10.0 mm, 1.0 to 8.0 mm, or 2.0 to 6.0 mm. The height h1 of the main body portion 24a (the length protruding from the general surface 23 toward the cavity C1 in the temperature raising portion 24) affects the sound absorption characteristics of the resin foam molded article. ˜10.0 mm, 4.0 to 8.0 mm, and 10 to 100% of the thickness d1 of the cavity C1 when the molding die is at the predetermined proximity position L1 (interval between opposing molding surfaces). Here, h1 ≦ d1 is to prevent interference between the tip 24c of the main body 24a and the molding surface 31 of the fixed mold. Further, from the viewpoint of forming the air vent M16a so as to penetrate the skin layer M16 and connect to the foam layer M12, the height h1 is preferably equal to or greater than the thickness d4 of the skin layer M16 formed in the resin foam molded body. . If h1 = d1, a through-hole penetrating in the thickness direction D1 is formed in the resin foam molded body, and it is possible to form a composite sound absorbing structure by overlapping with other sound absorbing materials.

  The diameter d12 of the root portion 24b can be set to, for example, 1.0 to 10.0 mm, 4.0 to 8.0 mm. In the example of the figure, an example in which d12 <d11 is shown. The depth h2 of the root portion 24b (the length protruding from the general surface 23 toward the general portion 22 in the temperature raising portion 24) is, for example, 1.0 to 10.0 mm, 4.0 to 8.0 mm, and the movable die 20. 10 to 100% of the thickness in the separation direction D1.

As a material of the heat insulating material 26 constituting the heat insulating structure, a material having a low thermal conductivity such as ceramic or polycarbonate resin can be used. For example, a material having a thermal conductivity of 0.1 to 50 W / m / K is used. Can do. Further, from the viewpoint of maintaining the temperature rising portion at a high temperature only by heat from the high temperature resin molding material without being heated by a heating mechanism, the heat conductivity of the heat insulating material is ½ or less of the heat conductivity of the general portion 22. Is preferable. Furthermore, it is preferable that the heat conductivity of the heat insulating material is ½ or less of the heat conductivity of the temperature raising portion 24. The heat insulating material 26 is formed in a substantially truncated cone shape in which the cavity side surface 26c is wider than the general side surface 26d, and the substantially cylindrical heating portion mounting hole 26a for inserting and mounting the root portion 24b of the heating member is a cavity. It is formed on the side surface 26c. Here, the inner peripheral surface of the temperature raising portion mounting hole 26a is shaped to match the outer peripheral surface of the root portion 24b, and the outer peripheral surface 26b of the heat insulating material 26 is shaped to match the inner peripheral surface of the heat insulating material mounting hole 21a. Yes.
The thickness h3 of the portion of the heat insulating material 26 where the temperature raising portion mounting hole 26a is formed is, for example, 0.5 to 10 inclusive, which is equal to or less than the length obtained by subtracting the depth h2 of the root portion 24b from the thickness in the separation direction D1 of the movable mold 20. .0 mm. The minimum thickness of the heat insulating material 26 around the root portion 24b is (d13-d12) / 2 in FIG. 4, for example, 0.5 to 10.0 mm at a distance d14 or less between the adjacent root portions 24b. Can do. In addition, the diameter of the cavity side surface of the heat insulating material 26 can be set to 2.0 to 15.0 mm, for example, and the diameter of the general part side of the heat insulating material 26 is less than the diameter of the cavity side surface, for example, 2.0 to 9.0 mm. can do.
As the heat insulating structure, a hollow layer that separates the general surface 23 and the temperature raising portion 24, a combination of the hollow layer and the heat insulating material, and the like can be considered.

  As shown in FIG. 3, each heat insulating material 26 is inserted into each heat insulating material mounting hole 21a and bonded and fixed, for example, with an adhesive, and the root portion of each temperature increasing member is inserted into the temperature increasing portion mounting hole 26a of each heat insulating material. When 24b is inserted and bonded and fixed with, for example, an adhesive, a movable molding surface 21 is formed. In addition, if the screw | thread screwed together in the internal peripheral surface of the heat insulating material attachment hole 21a and the outer peripheral surface 26b of heat insulating material is formed, the heat insulating material 26 can be screwed and fixed to the heat insulating material attachment hole 21a. Further, if a screw that is screwed to the inner peripheral surface of the temperature raising portion mounting hole 26a and the outer peripheral surface of the root portion 24b is formed, the temperature rising member 24 can be screwed and fixed to the temperature rising portion mounting hole 26a. it can.

In the case where a large number of temperature raising portions 24 are provided on the molding surface 21, in general, if the resin foam molding is uniformly dispersed over the entire surface of the resin foam molding excluding the peripheral portion, good sound absorption is obtained in the resin foam molding. However, it may be arranged unevenly depending on the shape of the interior material. For example, it is conceivable that a large number of temperature rising portions are arranged in a portion close to the ears of a passenger of an automobile, or a large number of temperature rising portions are arranged in a portion on the side where sound waves enter. Further, rather than arranging the temperature rising portions in a vertical and horizontal order, as shown in FIG. 8, arranging the temperature rising portions in a staggered manner to form the respective vent holes M16a increases the rigidity of the resin foam molded body. It is thought that you can.
The diameter (diameter d21) of the air holes M16a formed in the resin foam molded body M10 is preferably 0.5 to 10 mm, more preferably 1.0 to 8.0 mm, and even more preferably 2.0 to 6.0 mm. . When the diameter is set to the above lower limit or more, it is preferable in that sound waves can easily enter the ventilation hole and good sound absorption can be obtained, and when the diameter is set to the upper limit or less, it is preferable from the viewpoint of obtaining good rigidity for the sound absorbing panel. is there. When the vent hole has the same diameter as the main body portion 24a of the temperature raising member, the main body portion diameter d11 may be set to the desired vent hole diameter d21, and the vent hole has a smaller diameter than the main body portion 24a. The diameter d11 of the main body may be made larger than the desired diameter d21 of the vent according to the degree, and when the vent is larger than the main body 24a, the diameter d11 of the main body according to the degree. Should be smaller than the desired diameter d21 of the vent hole.

The total area S2 of the projected area of the vent hole M16a with respect to the projected area S1 of the molded body M10 when projected onto the surface PL1 perpendicular to the direction D1 in the thickness direction D1 of the resin foam molded body M10 is the opening ratio p of the skin layer. = (S2 / S1), the aperture ratio p is preferably 3 to 50% and more preferably 10 to 40% as a percentage. This is because when the aperture ratio is set to the lower limit or higher, the sound wave sufficiently passes through the vent hole and good sound absorption is obtained, and when the aperture ratio is set to the upper limit or less, the sound absorption panel is preferable because good rigidity is obtained. . Note that p = n1 × π (d1 / 2) ² / S1, where d21 is the diameter of each air hole M16a and n1 is the number of air holes M16a formed on one side of the skin layer.
The peak of the sound absorption coefficient shifts to the high frequency side as the aperture ratio p increases. Even at the same aperture ratio, the peak of the sound absorption coefficient shifts to the high frequency side when the diameter of the air hole becomes small, shifts to the high frequency side when the foam layer becomes thin, and shifts to the high frequency side when the skin layer becomes thin. Therefore, by adjusting these according to the size, number, and arrangement of the temperature raising portions, it is possible to optimize the mode of the vent holes in accordance with the use and arrangement position of the resin foam molded article.

The molding machine 10 includes a cooling mechanism 40 that cools the general surfaces 23 and 33 to a temperature lower than the melting point of the resin molding material M1 by removing heat from the movable general portion 22 and the fixed die 30. The melting point of the resin molding material is the temperature at which the crystallinity becomes invisible in the semicrystalline polymer due to heating when measured under specific test conditions, such as the melting temperature specified in JIS K6900. Can be defined. In the molding machine 10 shown in FIGS. 1 and 2, a cooling passage 41 is formed inside the movable general portion 22 and inside the fixed die 30, and cooling of cooling water or the like is performed in the cooling passage 41 by the liquid feeding mechanism 42. A cooling mechanism 40 that allows liquid (cooling medium) to pass through is shown. Of course, the cooling mechanism may be a mechanism that air-cools the movable general part and the stationary mold with air having a temperature lower than the melting point of the resin molding material. In addition, when the movable general part and the stationary mold are naturally air-cooled, it is not necessary to provide a cooling mechanism that actively cools.
What is necessary is just to determine the temperature of the general surfaces 23 and 33 according to the melting | fusing point of a resin molding material, the property of the resin foam molded object calculated | required, etc., for example, setting it as 30-80 degreeC at the temperature lower than the melting point of a resin molding material Can do. Further, from the viewpoint of surely forming the skin layer on the surface in contact with the general surface 23 and surely forming the air holes in the surface in contact with the temperature raising portion 24, the temperature of the general surface 23 is set to 20% higher than the temperature of the temperature raising portion 24. It is preferable that the temperature is lower by at least ° C.

The resin constituting the resin molding material M1 is preferably a thermoplastic resin (a kind of synthetic resin) from the viewpoint of being able to be heated and melted, but various thermosetting resins (such as a phenolic resin and a urea resin) 1 type), a modified resin in which a soft component such as a rubber component is blended with a synthetic resin to improve elastomeric properties, and the like can be used.
As the thermoplastic resin, an olefin resin, an olefin thermoplastic elastomer, or the like can be used. Either a homopolymer or a copolymer obtained by copolymerizing two or more types of monomers, an olefin and an unsaturated carboxylic acid can be used. Copolymerized copolymers or combinations thereof may be used. Specifically, polypropylene, polyethylene, acrylonitrile butadiene styrene resin (ABS resin), polyethylene terephthalate (PET), polyamide, polystyrene, combinations thereof, these resins For example, a modified resin in which a rubber component is blended can be used.
The melting point of the meltable resin molding material is, for example, 100 to 300 ° C. From the viewpoint of forming a skin layer on the surface in contact with the general surfaces 23 and 33 of the molding die, the melting point of the resin molding material is higher than the temperature of the general surfaces 23 and 33. Is preferably a high temperature, more preferably a temperature 20 ° C. higher than the temperature of the general surfaces 23 and 33.

  The foaming agent contained in the resin molding material M1 includes a physical foaming agent such as a gas inert gas or a volatile organic compound at a normal temperature of 1 atm, a chemical foaming agent that decomposes or reacts by heating to generate gas, and a combination thereof. Can be used. It is preferable to use an inert gas for the foaming agent because it does not react with the resin and does not deteriorate the resin. As the inert gas, carbon dioxide, nitrogen, argon, helium, neon, a combination thereof, or the like can be used. As the volatile organic compound, a volatile foaming agent that generates hydrocarbons such as butane and pentane can be used. As the chemical foaming agent, an inorganic foaming agent that generates a carbon dioxide gas such as ammonium carbonate or sodium hydrogen carbonate, an organic foaming agent that generates a gas of an organic compound such as polycarboxylic acid or azo compound, or the like may be used. it can.

  Here, when a nucleating agent is used in combination with an inert gas, the nucleating agent becomes an appropriate nucleating material, and bubbles are formed moderately densely and uniformly, and as an interior material while maintaining higher sound absorption A resin foam molded article having good tactile sensation can be formed. The addition ratio of the nucleating agent with respect to the resin molding material not containing the nucleating agent may be a blending ratio that functions as a nucleus for foaming the physical foaming agent. For example, 100 parts by weight of the resin molding material not containing the nucleating agent On the other hand, it can be in the range of 1 to 50 parts by weight (more preferably 1 to 20 parts by weight). Moreover, when using a chemical foaming agent as a nucleating agent, a chemical foaming agent has the function to assist foaming of an inert gas. In addition, by adjusting the blending ratio of the nucleating agent, the density of the foamed cells can be adjusted and the sound absorption can be adjusted. Further, the pressure of the inert gas injected into the resin molding material is preferably 0.5 to 20 MPa, and more preferably 1.0 to 7.0 MPa. When the pressure of the inert gas is set to the above lower limit or more, the amount of the inert gas dissolved in the resin molding material is sufficient, which is preferable in that a resin foam molded body having a high expansion ratio can be obtained. On the other hand, it is preferable to set the pressure of the inert gas below the upper limit because the inert gas is not wasted and a general-purpose product can be used for the gas injection device and the mold, resulting in a low cost.

The resin molding material M1 may be composed of only a resin and a foaming agent, but an additive may be included in the resin molding material M1. As additives, fillers such as talc, nucleating agents, pigments, lubricants, antioxidants, heat stabilizers, ultraviolet absorbers, antistatic agents, combinations thereof, and the like can be used. The blending ratio of each material in the resin molding material is 50% by weight (preferably 65% by weight or more) of resin and less than 50% by weight of additive (preferably 35% by weight) from the viewpoint of sufficiently retaining the properties of the resin. %)).
When talc is included in the resin molding material, the foam cell can be made smaller, and the foam cell can be made smaller as the blending amount of talc is increased. Therefore, by adjusting the weight ratio of talc contained in the resin molding material, the size of the foam cell can be adjusted to mold the resin foam molded body. Therefore, by adjusting the amount of talc, the sound absorption property of the resin foam molded article can be adjusted.

The general part M10a of the resin foam molded body M10 is formed at a position corresponding to the general surface 23 of the movable mold, and non-foamed skin layers M16 and M16 are formed on both surfaces in contact with the general surfaces 23 and 33 of the mold. The formed and sandwiched between both skin layers M16 and M16 is a foam layer M12.
The skin layer M16 is formed in a non-foamed state by the temperature of the resin molding material in contact with the general surfaces 23 and 33 having a temperature lower than that of the liquid resin molding material rapidly solidifying without foaming. The
The thickness d4 of the skin layer is controlled by the temperature of the resin molding material, the temperatures of the general surfaces 23 and 33, and the timing of separating the molds 20 and 30. If the temperature of the resin molding material or the molding surface of the molding die is lowered or the timing of separating the molding die is delayed, the skin layer becomes thick, and the temperature of the resin molding material or the molding surface of the molding die is increased or molded. If the mold separation timing is advanced, the skin layer becomes thinner. The thickness d4 of the skin layer is preferably 0.1 to 1.0 mm within a range less than half of the distance d1 between the molds 20 and 30. When the thickness d4 is not less than the above lower limit, good elasticity and good tactile sensation can be obtained as an interior material, and when the thickness d4 is not more than the above upper limit, the resin foam molded article is not too hard and good elasticity and good tactile sensation can be obtained. This is because it is preferable.

In the foam layer M12, a foam cell M13 is formed in which a bubble is continuously extended in a frost column by 1.0 mm or more in the separation direction D1 at a position corresponding to the general surface 23 at a separation distance d2 or less.
Referring to FIG. 6, a large number of micro bubbles in the resin molding material generated in the initial stage of the core back at a position corresponding to the general surface 23 are separated in the separation direction D1 by the separation of the mold and the foaming action of the foaming agent. The connecting port M13a is formed between the other bubbles adjacent to each other in the substantially separating direction, and is connected in a columnar shape in the separating direction. In the example of the figure, it is shown that bubbles a1, a2, a3, and a4 communicate with each other in the separating direction to form a columnar continuous cell. On the other hand, in the direction D2 perpendicular to the separation direction, the growth is suppressed by the presence of other adjacent bubbles, but the connection port M13b is formed between the other adjacent bubbles due to the thin wall of the cell. As a result, a frost column-like foam cell M13 extending in the separation direction D1 is formed. In the example of the figure, it is shown that the bubbles a2 and the bubbles b2 communicate with each other, the bubbles a1 and the bubbles c1 communicate with each other, and the foamed cells are organized in a frost column shape.
The foam cell M13 has a length d5 in the separation direction that is very large with respect to the diameter of each columnar cell in the vertical direction D2, and has a shape different from the concept of an ellipsoid or spindle. Here, the length d5 of the foam cell in the separation direction is the length of the longest portion of the connected bubbles in the separation direction D1, that is, the position in the vertical direction that is the uppermost of the bubbles connected in the drawing. The length of the vertical difference from the lower vertical position is assumed. Further, when viewed in the cross section in the vertical direction D2, as a result of the bubbles being connected in a staggered manner like the bubbles a1, a2, a3, and a4, the cross section of the cell becomes zigzag, which is different from the concept of a circle or ellipse. Tend to be. In addition, a foam cell may become the length connected with the both skin layers in the both sides of a foam layer.

The foam layer M12 at a position corresponding to the general surface 23 is formed so as to have air permeability in the direction D1 perpendicular to the separation direction as a result of the formation of the frost column-like foam cells M13. Here, when the foamed layer is formed so that the air permeability according to the fragile method of JIS L1096 when cut to a thickness of 5.0 mm in the vertical direction D2 is 0.4 cc / cm ² / sec or more, it is high. A sound-absorbing resin foam molding is obtained. Here, in order to increase the air permeability of the foam layer in the vertical direction D2, for example, the foam cell M13 may be elongated in the separation direction D1, and the separation distance d2 of the mold may be increased. Further, the air permeability in the vertical direction D2 of the foam layer can be adjusted by adjusting the separation distance d2 of the mold.
Furthermore, when the resin foam molded body is molded so that the density of the foamed layer is 0.03 to 0.5 g / cm ^3, it is less likely to buckle against the compressive force in the thickness direction and has good elasticity and good as an interior material. It becomes possible to obtain tactile sensation and high sound absorption. Here, in order to reduce the density of the foam layer, for example, the foam cell M13 may be lengthened in the separation direction D1, and the separation distance d2 of the mold may be lengthened. Further, the density of the foam layer can be adjusted by adjusting the separation distance d2 of the mold. The expansion ratio is (d1 + d2) / d1, where d1 is the distance between the pair of molds when they are close to each other, and d2 is the separation distance. Since the approximate density of the foamed layer can be obtained from the required foaming ratio, the density of the resin molding material, and the thickness d4 of the skin layer, the density of the foamed layer can be determined by examining the foaming ratio, the density of the resin molding material, and the thickness d4 of the skin layer. The density can be adjusted.

  In the foam layer M12, an intermediate layer having foam cells that are short in the separation direction D2 may be formed on a portion of the surface side in contact with the skin layers M16 and M16. The foam cell of the intermediate layer may be an independent cell in which adjacent bubbles are not connected or communicated.

  Next, with reference to FIG. 1 and FIG. 5, each step of the manufacturing method of this resin foam molding is demonstrated with the change of the state of the resin molding material in a cavity. Note that a thermoplastic resin is used as the resin constituting the resin molding material.

First, as shown in the upper part of FIG. 1, the male and female molds 20 and 30 in the mold open state are closed to form the cavity C1 (timing t1 to t2 in FIG. 5). At this time, the mold 20 is at a predetermined proximity position L1, and the distance between the molds 20 and 30 is d1. Moreover, the resin molding material M1 containing a foaming agent is made into a high-temperature liquid above melting | fusing point MP, and the shaping | molding die 20 and 30 is made into temperature (for example, 30-80 degreeC) lower than melting | fusing point MP. In addition, if a resin molding material is heated more than melting | fusing point and it is made into a molten state, it can be made a high temperature liquid state. For example, when polypropylene having a melting point of 160 ° C. is used as the thermoplastic resin, the resin molding material is heated to about 170 to 230 ° C. to melt the polypropylene.
Next, as shown in the middle stage of FIG. 1, the molten resin molding material M1 is injected into the cavity C1 with an injection pressure of 100 to 200 MPa and a filling time of 0.5 to 5 seconds. (Timing t2 to t3 in FIG. 5). The injection pressure and the filling time vary mainly depending on the amount of the resin molding material to be injected, that is, the size of the resin foam molded body. The filled resin molding material also wraps around the body portion 24a of the temperature raising member protruding into the cavity and covers the body portion. Here, the temperature raising member 24 is insulated from the general surface 23 by the heat insulating material 26 to prevent cooling, and heat is supplied from the high temperature resin molding material to approach the temperature of the resin molding material. As a result of continuous batch molding, the temperature of the temperature raising member 24 is maintained at a temperature higher by about 20 to 200 ° C., for example, than the temperature of the general surfaces 23 and 33.

As shown in the upper part of FIG. 7, for the resin molding material M1 filled in the cavity C2, for convenience, low temperature regions R1 and R2 below a predetermined temperature (for example, the temperature at which the resin molding material solidifies), and the predetermined temperature The region is divided into a higher temperature region R3 (a region marked with dots in the figure). The temperature distribution of the resin molding material is a distribution in which the high temperature region R3 is sandwiched between the low temperature regions R1 and R2 on the surface side at the position corresponding to the general surface 23, and the temperature rising member has a high temperature at the position corresponding to the temperature increasing member 24. The region R3 is in contact with the distribution.
Thus, since the temperature of the movable mold general part 22 and the fixed mold 30 is low, the resin molding material in the part in contact with the general surfaces 23 and 33 of the mold is first cooled and solidified to form the molds 20 and 30. Is formed as a non-foamed skin layer of 0.1 to 1.0 mm within a range of less than half of the distance d1 between. Moreover, the resin molding material inside the skin layer maintains a molten state. On the other hand, the resin molding material in contact with the temperature raising member 24 is maintained in a state where cooling is delayed and a clear skin layer is not formed.

When the resin molding material is injected, a plurality of micro bubbles start to be generated. When a nucleating agent is included in the resin molding material, the nucleating agent becomes a nucleating material, and in the molten resin molding material, inert gas gathers around the nucleating agent to form an isotropic spherical shape. A large number of micro bubbles having a diameter of less than 0.1 mm begin to form. This stage is the initial foaming stage.
The time T1 (timing t3 to t4 in FIG. 5) for holding the molds 20 and 30 at the proximity position L1 is preferably 1 to 10 seconds, and more preferably 3 to 7 seconds. When the holding time T1 is set to 3 seconds or more, the viscosity of the resin molding material is moderately high, and the foamed cells are hardly cut in the middle of the separation direction D1 at the position corresponding to the general surface 23. The holding time T1 is less than the above upper limit. In this case, insufficient foaming due to solidification does not occur. When the temperature of the resin molding material or the temperature of the mold is low, or when the speed at which the mold 20 is separated (separation speed) is slowed, the holding time T1 can be shortened so that the resin viscosity does not increase too much. Good. When the mold is held in the proximity position, a skin layer is formed between them, the temperature of the resin molding material inside the skin layer is lowered, and the shear viscosity is increased.

After the timing t4, as shown in the lower part of FIG. 1, the male and female molds 20, 30 are separated from each other to a predetermined separation position L2, and the volume of the cavity C1 is expanded (timing t4 to t5 in FIG. 5). Then, the plurality of micro cells formed in the resin molding material in the initial foaming stage are expanded only in the separation direction D1 with the separation of the molding die, and communicate with other bubbles that are substantially adjacent in the separation direction. A part of the air bubbles communicates with other adjacent bubbles in the direction D2 perpendicular to the separation direction. As a result, as shown in the lower part of FIG. 7, at the position corresponding to the general surface 23, the foam layer M <b> 12 having the frost column-shaped foam cells M <b> 13 extending in the separation direction D <b> 1 is between the skin layers M <b> 16 and M <b> 16 on the surface. The foamed layer is formed so as to have air permeability in a direction D2 perpendicular to the separating direction. On the other hand, at the position corresponding to the temperature raising member 24, the high temperature region R3 is wide. By cutting, a cavity M15 is formed inside. Further, the temperature of the resin molding material in contact with the temperature raising member 24 is higher (for example, higher than 20 ° C.) than the temperature of the resin molding material in contact with the general surface 23 and has a low viscosity (for example, shear viscosity of 10 ¹ to 10 ^3). Pa · s), the air hole M16a is formed so as to penetrate the skin layer M16 and connect to the cavity M15.
The cavity M15 is generally substantially oval, for example, the major axis is about 80 to 100% of the separation distance d2, and the minor axis is about 100 to 150% of the diameter d11 of the body portion 24a of the temperature raising member. The reason why the minor axis is d11 or more is presumed that the wall of the foam cell is cut around the main body of the temperature raising member. In addition, adjacent cavities formed by adjacent temperature raising members may be partially connected. The cavity M15 has a structure for absorbing sound by taking sound waves into the resin foam molded body M10. Therefore, the structure of the temperature raising portion may be set so that the cavity M15 having a size and shape that optimizes the sound absorption performance is formed.
In the separation step, the separation speed V1 of the mold 20 is preferably 1 to 100 mm / second, and more preferably 10 to 60 mm / second. This is because when the separation speed V1 is equal to or higher than the lower limit, a phenomenon in which foaming does not occur does not occur, and when the separation speed V1 is equal to or lower than the upper limit, a phenomenon that the structure of the frosted columnar foam cell does not collapse occurs. This is because an inexpensive injection molding machine can be used. The time for separating from the proximity position L1 to the separation position L2 is about 0.02 to 3 seconds.

  In the separation step (when the molds 20 and 30 are spaced apart), the resin molding material having the test temperature as the temperature of the resin molding material inside the cavity inside the skin layer (for example, the temperature at the center of the cavity) The melt tension of is preferably from 0.1 to 30 gf, more preferably from 0.2 to 1.0 gf. However, the melt tension of the resin molding material was determined by using a capillary rheometer “Capillograph 1C type” manufactured by Toyo Seiki Seisakusho Co., Ltd. in accordance with JIS K7199. The cylinder is filled with the resin molding material at a temperature, the piston of the capillary rheometer is lowered at a descending speed of 10 mm / min, and the resin molding material in the cylinder is extruded from the capillary into a thread shape. At the same time, the extruded resin molding material is 5 The melt tension measured when the sheet is drawn at a take-up speed of 0.0 m / min. When the resin molding material is a thermoplastic material, the resin molding material is heated and melted, and the molten resin molding material is injected into the cavity when the molding dies 20 and 30 are in the proximity position L1. The highest temperature among the resin molding materials in the cavity when separating 20 and 30 is set as the test temperature, the resin molding material in a molten state at the test temperature is filled in the cylinder, and the piston is lowered to form the resin molding. What is necessary is just to measure melt tension, when material is extruded and taken out in the shape of a thread. If the melt tension of the resin molding material is as small as less than 0.1 gf, the foamed cell wall is cut when the mold is separated and the foamed cell is not formed in the form of frost columns. When the melt tension of the molding material is too large (greater than 30 gf), even if the mold is separated, the foamed cells are not formed in the form of frost columns, and the air permeability is hardly present and the sound absorption is low.

Further, the separation distance d2 of the mold is determined by the expansion ratio of the resin foam molded product to be obtained, and is 2.0 to 9 of the distance d1 between the molds 20 and 30 when in the proximity position L1. 0.0 times (the foaming ratio of the resin foam molding is 3 to 10 times) is preferable, and 2.0 to 5.0 times the distance d1 (the foaming ratio of the resin foam molding is 3 to 6 times) is more preferable. In other words, the volume ratio of the cavity C1 when the molds 20 and 30 are separated from the proximity position L1 to the separation position L2 is preferably 3 to 10, and more preferably 3 to 6. When the volume ratio of the cavities (separation distance d2) is equal to or greater than the lower limit, the foamed cells are frost columns in the separation direction D1 at a position corresponding to the general surface 23 and become sufficiently long to increase the air permeability. If the upper limit is not reached, the foamed cells are not cut in the middle of the thickness direction (separating direction D1) at the position corresponding to the general surface 23, so that good elasticity and good tactile sensation as an interior material can be obtained.
In this manufacturing method, the distance d1 between the two molds at the close position is set to 1.0 to 10.0 mm, and the separation distance d2 is set to 1.0 to 50.0 mm. The foam cell M13 at the position is formed in a frost column shape in which bubbles are continuously extended by 1.0 mm or more at a separation distance d2 or less in the separation direction D1.

  In addition, the speed at the position reaching the separation position L2 is made larger than the speed at the position where the pair of molds 20 and 30 are separated from the proximity position L1 at the speed V1, and the resin foam molding is obtained. If it shape | molds, since a foam cell can be stably formed in a frost column shape in the position corresponding to the general surface 23, the elasticity and tactile sense as an interior material can be made further favorable, maintaining high sound absorption. For example, at the timing t4 to t5, by gradually or stepwise increasing the separation speed V1 of the mold 20, the position at which the mold 20 reaches the separation position L2 rather than the speed at the position where the separation starts from the proximity position L1. Increase the speed.

When the separation step is finished, the mold 20 is held at the separation position L2 for a predetermined time (timing t5 to t6 in FIG. 5). The time T2 for holding the mold in the spaced position is sufficient if the internal foamed layer is cooled and solidified, for example, about 30 seconds.
Finally, the molds 20 and 30 in the clamped state are opened at the separation position L2, the cavity is opened (timing t6 to t7 in FIG. 5), and the resin foam molded body M10 is taken out to complete a series of manufacturing cycles. To do.

The formed resin foam molded body M10 has a thin and wide shape, and a non-foamed skin layer M16 is formed on the surface in contact with the general surfaces 23 and 33. A breathable foam layer M12 having frost columnar foam cells M13 extended with continuous bubbles of 1 mm or more is formed, and a cavity M15 is formed inside at a position corresponding to the temperature raising member 24, and penetrates the skin layer M16. Thus, a ventilation hole M16a is formed so as to be connected to the cavity M15. As a result, the resin foam molded body has a frost columnar foam cell (for example, a thickness of 0.1 to 1.0 mm and a density of 0.8 to 1.0 g / cm ² ) at a position corresponding to the general surface 23 (for example, Density 0.03 to 0.5 g / cm < ² >) is sandwiched, and at a position corresponding to the temperature raising member 24, the air hole M16a penetrates the skin layer M16 and the bottom M16a1 communicates with the back cavity M15. It becomes.
Then, as shown in FIG. 8, the sound wave toward the resin foam molded body M10 enters the cavity M15 from the vent hole M16a, enters the breathable frost columnar foam cell M13 by the foam layer M12, and energy is absorbed, Almost no reflection. Accordingly, noise such as noise is absorbed by the foamed layer M12, and it is possible to improve the quietness of the passenger compartment of the automobile. Moreover, since cavities are dispersed and exist between the frost column-shaped foamed cells, the elastic material can be easily buckled against a compressive force in the thickness direction while being lightweight, and good elasticity can be obtained as an interior material. Therefore, the resin foam molded article as a whole has useful effects such as low density, self-shape, good tactile sensation, high sound absorption, and the ability to be exhibited even when thin.

This resin foam molding can be used alone or in combination with a skin material as a sound absorbing panel. As shown in FIG. 9, pillar garnish P1 for automobile, package tray trim P2 for automobile, door trim (not shown), sun It can be used for various automotive interior materials such as a visor (not shown).
FIG. 11 shows a sound absorbing panel in which a breathable skin material M17 is laminated on the surface side of the skin layer M16. Here, the sound absorbing panel M101 shows an example in which a skin material M17 is attached to both surfaces of the resin foam molded body M10. Further, the sound absorbing panel M102 shows an example in which the skin material M17 is pasted only on one surface of the resin foam molded body M20 formed by the molding dies 20 and 30 shown in FIG. ing.
The skin material M17 is provided on the surface of the sound-absorbing panel for the purpose of imparting design properties as an automobile interior material. For example, a woven fabric, a nonwoven fabric having a thickness of 0.2 to 8.0 mm and a basis weight of 50 to 600 g / m ² , Knit, various leathers with a large number of minute ventilation holes, and the like can be used. Laminating a breathable skin material on the skin layer will decorate the surface of the sound absorbing panel, give the sound absorbing panel a soft feel, prevent damage to the sound absorbing panel, and improve sound absorbing properties. be able to. In addition, when a highly breathable skin material having an air permeability of 6 cc / cm ² / sec or more according to JIS L1096 is used for the skin material M17, it is possible to improve the design without reducing the sound absorption effect.

  As described above, when the molds 20 and 30 are separated from each other, the surface of the resin molding material in contact with the general surfaces 23 and 33 of the mold is cooled to form a non-foamed skin layer. Openings are formed on the surface of the resin molding material that is in contact with the temperature rising portion at a higher temperature. Thereby, it is not necessary to form a hole in the surface of the resin foam molded article by post-processing, and a resin foam molded article having good sound absorption at the same time as molding can be obtained. Therefore, it is possible to provide a rational method for forming a large number of openings in the skin layer of the resin foam molded article, and it is possible to improve the production efficiency of a resin foam molded article having good sound absorption. In addition, since the opening is a vent hole that penetrates through the skin layer to the internal cavity, a resin foam molded article having very good sound absorption is obtained. In addition, since the general surface and the temperature rising part are insulated, the temperature rising part can be maintained at a temperature higher than that of the general surface without heating with a separate heating mechanism, and the hole is reliably formed and very good. A sound-absorbing molded article can be obtained. Furthermore, since the temperature raising portion protrudes from the general surface toward the cavity, it is possible to reliably form an opening and obtain a molded article having a very good sound absorbing property. Furthermore, since a cooling mechanism for cooling the general surface to a temperature lower than the melting point of the resin molding material is provided, a skin layer can be surely formed and a good sound-absorbing molded body can be obtained.

(2) Modification:
As shown in FIG. 12, holes can be formed on the surface of the resin foam molded body using the temperature rising portions 71 to 75 having various shapes. The temperature raising member 71 has a columnar main body 71a and a root 71b having a diameter larger than that of the main body. As a result, a large amount of heat from the resin molding material can be accumulated in the root portion 71b, and it becomes possible to obtain a molded article with good sound absorption while maintaining the temperature rising portion at a higher temperature than the general surface more reliably. . The temperature raising member 72 has a body portion 72a on the substantially cylindrical cavity side and a root portion 72b on the general portion side of the mold, and a number of sharp teeth are formed on the tip portion 72c. The temperature raising member 73 has a substantially conical apex portion as a tip portion 73a, a cavity side as a main body portion 73a, and a general portion side as a root portion 73b, and a plurality of blades 73d are formed on the side surface of the main body portion. Like the pencil, the temperature raising member 74 has a tip portion 74c having a conical shape, a general portion side from the tip portion is a cylindrical shape, a cavity side is a main body portion 74a, and a general portion side is a root portion 74b. On the contrary, the temperature raising member 75 has a tip portion 75c recessed in a conical shape so that the peripheral portion protrudes and the inside is depressed, the general portion side from this tip portion is a cylindrical shape, and the cavity side is the main body portion 75a, The general part side is a root part 75b.

As shown in FIG. 13, a heating mechanism 50 that actively heats the temperature raising portion 24 to a temperature higher than the general surface 23 of the mold (preferably to a temperature higher than 20 ° C.) may be provided. In the figure, a heat conducting member 54 in contact with the root 24b of each temperature raising member 24 is provided inside the movable general part 22, and a heating passage 51 is formed inside the movable general part 22, and the general part 22, a heat insulating material (heat insulating structure) 53 that insulates the heating passage 51, the heat conducting member 54, and the root portion 24b of the temperature raising member is provided between the respective portions 51, 54, 24b and the general portion 22, and a liquid feeding mechanism 52 is provided. 1 shows a heating mechanism 50 that allows a heating liquid (heating medium) such as heating oil to pass through the heating passage 51. Of course, the heating mechanism may be a mechanism that heats the temperature rising section by passing a current through a heater provided in contact with the temperature rising section in the movable general portion. The heat conducting member 54 is formed of a metal such as aluminum or copper having a high heat conductivity, and transfers heat from the heating medium to each root portion 24b. The heating mechanism may heat the temperature raising portion to the melting point MP or higher of the resin molding material M1, or may be heated to a temperature lower than the melting point MP. In any case, the temperature drop of the resin molding material in contact with the temperature raising portion can be delayed. Then, since the temperature of the temperature raising portion is surely higher than that of the general surface, it is possible to reliably form the aperture and obtain a good sound-absorbing molded body.
Also in this case, the temperature raising members 71 to 75 shown in FIG. When the temperature raising member 71 is used, a heating medium circulation pipe is installed in the general part 22 so as to be in contact with the root 71b having a large diameter, and the heating medium controlled to a predetermined temperature is circulated to increase the temperature. The temperature of the member can be controlled to a high temperature.

Note that the mechanism 50 shown in FIG. 13 may be a temperature control mechanism capable of heating and cooling. In this case, the passage 51 serves as a medium passage for the heating medium and the cooling medium, and the liquid feeding mechanism 52 serves as a mechanism for sending the heating medium and the cooling medium to the medium passage 51. Oil, water, etc. can be used as the heating medium and the cooling medium. Of course, the temperature control mechanism 50 may be a mechanism that heats and cools the temperature rising section by passing a current through a heater provided in contact with the temperature rising section in the movable general portion. If a temperature sensor for detecting the temperature of the temperature raising unit is installed, the temperature raising unit can be feedback-controlled to the target temperature based on the temperature detected by the temperature sensor, and a temperature gradient can be provided in the temperature raising unit.
By providing the temperature control mechanism, it is possible to stably maintain the temperature raising portion within a predetermined temperature range and stably repeat the molding. In addition, by forcibly cooling the temperature rising portion after the mold is separated (timing t5 to t6), the resin foam molded body can be solidified reliably, and a resin foam molded body having a stable shape can be obtained. .

  As shown in FIG. 14, the temperature raising member 76 may be provided so as to be embedded in the general surface 23 without protruding from the general surface 23 to the cavity. Even in this case, the temperature raising portion 76 has a temperature higher than that of the general surface 23. Therefore, by separating the mold, the resin foam molded body has a non-foamed skin layer on the surface in contact with the general surface 23. An opening is formed on the surface formed and in contact with the temperature raising portion 76. In the example of the figure, for example, a skin layer is formed on the surface in contact with the general surface 23 cooled to a temperature lower than the melting point MP of the resin molding material by the cooling mechanism 40, and the heating mechanism 50 causes the heating unit 76 to By being heated to the melting point MP or higher, a vent hole penetrating the skin layer and leading to the internal cavity is formed.

  As shown in FIGS. 15 and 16, a slide drive mechanism 60 that slides the temperature raising unit 24 in both directions is provided, and when the air vent M16a is formed, the temperature raising unit 24 is advanced toward the cavity C1, A resin foam molding may be molded. The temperature raising member 24 of the molding machine 10 is bi-directionally advanced and retracted toward the cavity C1 between a predetermined retracted position (position shown in FIG. 15) and a predetermined advanced position (position shown in FIG. 16) ( It is possible to slide in the separating direction D1). In the figure, the heat conducting member 54 in contact with the root 24 b of each temperature raising member 24 is provided inside the movable general part 22, and the heater 55 is located inside the movable general part 22. And a heat insulating material (heat insulating structure) 53 that insulates the heater 55, the heat conducting member 54, and the root portion 24b of the temperature raising member from the general portion 22 between the respective portions 55, 54, 24b and the general portion 22. The provided heating mechanism 50 is shown. Of course, the various mechanisms described above can be used as the heating mechanism. Here, the heat conducting member 54 and the heater 55 are slidable in both directions (separating direction D1) together with the temperature raising member 24. For example, the slide drive mechanism 60 is attached to the heat conducting member 54 in the general portion 22 and slides in both directions (separating direction D1) by itself to slide the heat conducting member 54, the temperature raising member 24, and the heater 55. A piston member 61 to be operated and a cylinder 62 that slide-drives the piston member 61 in both directions (separating direction D1) by hydraulic pressure or the like can be used.

The length protruding from the general surface 23 toward the cavity C1 in the temperature raising portion 24 when it is at the predetermined advance position is, for example, 1.0 to 10.0 mm, 1.0 to 5.0 mm, and the mold is predetermined. 10 to 100% of the thickness d1 of the cavity C1 at the close position L1. The length protruding from the general surface 23 of the temperature raising unit 24 toward the cavity C1 at the predetermined retraction position can be set to 0.0 mm (not protruding) to 1.0 mm, for example. The distance that the temperature raising unit 24 slides is determined by the distance between the retracted position and the advanced position, and can be, for example, 1.0 to 10.0 mm, 1.0 to 5.0 mm.
The temperature raising member 24 shown in FIG. 4 and the like, the temperature raising members 71 to 75 shown in FIG. From the viewpoint of breaking through the skin layer, it is preferable to use the temperature raising members 72 to 75 having sharp tips.

  With the above configuration, since the temperature raising member 24 advances to a predetermined advance position toward the cavity C1 filled with the resin molding material M1, it is possible to reliably form an opening and form a very good sound-absorbing molded article. Obtainable.

When the temperature raising member 24 is advanced with reference to FIG. 5, timings t11 to t12 at which the temperature raising member 24 is advanced toward the cavity C1 at the same time as the molds 20 and 30 are separated. Can do. In the example shown in the figure, t11 = t4 and t12 is set between t4 and t5. However, t12 = t5 may be set, or t1 may be set between t4 and t5. The period of time t11 to t12 is about 0.02 to 3 seconds. In the present modification, the temperature raising member 24 slides toward the cavity simultaneously with the separation of the molding dies 20 and 30 to form the vent hole M16a on the surface of the resin molding material. Therefore, the resin foam molded body having the vent holes on the surface. It becomes possible to improve the manufacturing efficiency of the.
The timing for retracting the temperature raising member 24 may be from the end of the timing t5 to the next molding timing t1.
Further, as the temperature of the temperature raising member 24 becomes closer to the temperature of the resin molding material at the time of injection (timing t2 to t3), a new skin layer does not form around the body portion 24a of the temperature raising member and the foam layer is surely reached. A through-hole is formed, and a resin foam molded article having good sound absorption is obtained.

  Further, the temperature raising member 24 may be advanced toward the cavity C1 after the timing t5 when the molds 20 and 30 are separated to the separation position L2 (timing t13 to t14). In the example shown in the figure, t13 and t14 are both between t5 and t6, but t13 = t5 may be used, and the temperature rise that can break through the surface of the solidified resin foam molded body such as the temperature raising members 72 to 75 If a member is used, t14 = t6 may be set. The period of time t13 to t14 is about 0.02 to 3 seconds. In this modification, since the temperature of the resin molding material is lowered in both the skin layer and the foam layer, mechanical perforation is performed rather than perforation in which solidification is prevented by heat. The cavity in the foamed layer is less bulging like an oval and has a shape close to a cylinder having a diameter of the temperature raising member. In this modification, the process can be simplified, the apparatus can be simplified, and the skin layer can be reliably perforated to obtain a resin foam molded body having a more stable shape of air vents on the surface. It becomes possible.

  In addition, this invention is not restricted to the Example and modification which were mentioned above, Each structure disclosed in the Example and modification which were mentioned above mutually replaced, the structure which changed the combination, well-known technique, and the above-mentioned Configurations in which the respective configurations disclosed in the embodiments and the modified examples are mutually replaced or combinations are changed are also included.

Sectional drawing which shows typically the manufacturing method of a resin foaming molding. Sectional drawing which shows typically the manufacturing apparatus of a resin foaming molding. The disassembled perspective view which shows a mode that a heat insulating material and a temperature rising member are attached to a shaping | molding die. The vertical sectional view which shows the principal part of the shaping | molding die which forms a cavity. The timing chart which shows the movement amount of a shaping | molding die. The vertical sectional view which shows the structure of the general part of a resin foaming molding. Sectional drawing which shows the change of the resin molding material with which the cavity was filled. The top view and vertical sectional view which show a part of resin foaming molding. The perspective view which shows the external appearance of the interior material for motor vehicles which applied this resin foaming molding. The vertical sectional view which shows the principal part of the shaping | molding die which forms a cavity in a modification. The vertical sectional view which shows the sound-absorbing panel using the resin foaming molding. The perspective view which shows the various modifications of a temperature rising part. Sectional drawing which shows typically the manufacturing apparatus provided with the heating mechanism (temperature control mechanism). Sectional drawing which shows typically the principal part of the resin foam molded object manufacturing apparatus in a modification. Sectional drawing which shows typically the manufacturing apparatus provided with the slide drive mechanism. Sectional drawing which shows typically the mode of the manufacturing apparatus which made the temperature rising part advance.

Explanation of symbols

10: Foam injection molding machine,
20, 30 ... a pair of molds,
21, 31 ... molding surface, 21 a ... heat insulating material mounting hole,
22, 32 ... General part, 23, 33 ... General surface,
24, 71-76 ... temperature rising member (temperature raising part), 24a ... main body part, 24b ... root part,
26 ... heat insulating material (heat insulating structure), 26a ... temperature rising part mounting hole, 26b ... outer peripheral surface,
40 ... Cooling mechanism, 41 ... Cooling passage, 42 ... Liquid feeding mechanism,
50 ... heating mechanism (temperature control mechanism), 51 ... heating passage (medium passage), 52 ... liquid feeding mechanism,
53 ... heat insulating material (heat insulating structure), 54 ... heat conducting member, 55 ... heater,
60 ... slide drive mechanism, 61 ... piston member, 62 ... cylinder,
C1 ... cavity,
D1 ... separation direction, D2 ... direction perpendicular to the separation direction,
L1: a predetermined proximity position, L2: a predetermined separation position,
M1 ... resin molding material,
M10, M20 ... resin foam molding,
M10a ... general part, M10b ... general surface,
M12 ... foam layer, M13 ... foam cell,
M15 ... hollow,
M16 ... Skin layer,
M16a ... vent (opening), M16a1 ... bottom of vent,
M17 ... skin material,
M101, M102 ... sound absorbing panel,
PL1 ... a surface perpendicular to the thickness direction of the resin foam molding,

Claims (10)

A cavity formed when a pair of molds that can approach and separate from each other is brought close to a predetermined proximity position, and a resin molding material containing a foaming agent is filled in the cavity, and then the pair of molds are separated to a predetermined separation position. And expanding the cavity to form a foamed cell in the resin molding material in the cavity to mold a resin foam molded article,
A non-foamed skin is provided on the surface in contact with the general surface by providing at least one general surface and a temperature raising portion having a temperature higher than the general surface on at least one molding surface of the mold, and separating the pair of molds A method for producing a resin foam molded article, comprising forming a hole in a surface in contact with the temperature raising portion while forming a layer, and molding the resin foam molded article.   In the resin molding material filled in the cavity, the temperature at the position corresponding to the temperature rising portion is made higher than the temperature at the position corresponding to the general surface, and the pair of molds are separated from each other to raise the temperature rising portion. 2. The resin foam molded body is formed by forming a cavity inside at a position corresponding to 1 and forming the opening so as to penetrate the skin layer and connect to the cavity. The manufacturing method of the resin foaming molding of description.   3. The resin foam molded body is formed by further providing a heat insulating structure that insulates the general surface and the temperature rising portion on at least one molding surface of the molding die. The manufacturing method of the resin foaming molding of description.   The resin foam molding according to any one of claims 1 to 3, wherein the resin foam molding is molded in a shape in which the temperature raising portion is protruded toward the cavity from the general surface. Body manufacturing method.   The length protruding from the general surface toward the cavity in the temperature raising part is equal to or greater than the thickness of the skin layer formed on the resin foam molded body, and is opposed to the pair of molds in the proximity position. 5. The method for producing a resin foam molded article according to claim 4, wherein the resin foam molded article is molded to be equal to or less than a distance between molding surfaces.   A cooling mechanism that cools the general surface to a temperature lower than the melting point of the resin molding material, and a heating mechanism that heats the temperature raising portion to a temperature higher than the general surface, and molding the resin foam molded body. The method for producing a resin foam molded article according to any one of claims 1 to 5.   The temperature raising portion is slidable in both directions to advance and retreat toward the cavity, and a slide driving mechanism is provided to slide the temperature raising portion in both directions, and the temperature raising portion is formed when the opening is formed. The method for producing a resin foam molded body according to any one of claims 1 to 6, wherein the resin foam molded body is molded by advancing a portion toward the cavity.   8. The resin foam molded body according to claim 7, wherein the resin foam molded body is molded by moving the temperature raising portion toward the cavity simultaneously with separating the pair of molds. Method.   8. The resin foam molding according to claim 7, wherein after the pair of molding dies are separated to the separation position, the temperature rising portion is advanced toward the cavity to mold the resin foam molding. Body manufacturing method. A cavity formed when a pair of molds that can approach and separate from each other is brought close to a predetermined proximity position, and a resin molding material containing a foaming agent is filled in the cavity, and then the pair of molds are separated to a predetermined separation position. A resin foam molded body formed by forming foam cells in the resin molding material in the cavity by expanding the cavity,
A non-foamed skin is formed on the surface in contact with the general surface by providing at least one general surface and a temperature raising portion having a temperature higher than the general surface on at least one molding surface of the mold and separating the pair of molds A resin foam molded article formed by forming an opening in a surface in contact with the temperature raising portion while forming a layer.

Images