JP2010046920A - Method of manufacturing skin-coated expanded molded form of polystyrene-based resin and skin-coated expanded molded form of polystyrene-based resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a skin-coated expanded particle molded form of polystyrene-based resin which undergoes such procedures as filling the interior of a blow-molded hollow molded form with an expanded particle, then, making an expanded particle molded form by fusion-bonding the expanded particles mutually and thus, fusion-bonding the inner surface of the skin consisting of the hollow molded form and the expanded particle molded form into one piece. <P>SOLUTION: This method is to manufacture the expanded particle molded form which is coated with a skin, by filling the interior of the hollow molded form with the expanded particle using a blow molding process. The temperature of a mold 1 during clamping a blow molding die is set to [glass transition temperature of hollow molded form base resin-30°C] to [glass transition temperature of hollow molded form base resin+30°C]. Further, one of a plurality of steam supply/discharge pins 22 which are inserted in the hollow molded form, is given as a steam supply side and the other as a steam discharge side. The mold 1 is heated by controlling the steam temperature T1 of the steam supply port of the steam supply-side pin 21 to [glass transition temperature of expanded particle base resin+10°C] to [glass transition temperature of expanded particle base resin+30°C]. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a skin-coated polystyrene-based resin foam molded body in which substantially the entire surface of a polystyrene-based resin expanded particle molded body is covered with a skin, and more specifically, comprises a polystyrene resin hollow molded body formed by blow molding. Filling the surface with polystyrene resin foam particles, forming the polystyrene resin foam particles by heating and fusing the foam particles, and fusing and integrating the skin with the foam particles molding, The present invention relates to a method for producing a skin-coated polystyrene-based resin foam molded article. Furthermore, the present invention comprises an outer skin made of a polystyrene resin hollow molded body formed by blow molding and a polystyrene resin foamed particle molded body located in the outer skin, and the skin and foam are formed even if the thickness of the skin is thin. The present invention relates to a skin-coated polystyrene-based resin foam molded article firmly adhered to a particle molded article.

  2. Description of the Related Art Conventionally, there is known a skin-covered foamed molded body comprising a hollow skin and a foamed particle molded body positioned inside the skin, wherein the skin and the foamed particle molded body are fused and integrated. A method for producing a foamed molded body in which substantially the entire surface of such a foamed particle molded body is covered with a skin is, for example, suspended between split molds for blow molding as shown in Patent Document 1 below. The resin parison is sandwiched between the molds and blow molded while the resin parison is in a softened state to form a hollow molded body. Then, while the hollow molded body retains a considerable amount of heat, A method of filling a foamed particle and blowing steam to fuse the foamed particles to each other and fuse and integrate with the skin, and then cooling to obtain a foamed molded body covered with the skin is known. ing.

  Further, regarding a skin-covered foamed molded article having a thin skin with a skin of 0.3 to 3 mm, Patent Document 2 discloses a water tray tray for an air conditioner and a method for producing the same by a blow molding method. Further, before the blow hollow molded body is cooled and solidified as in Patent Document 1, foamed particles are filled in the hollow molded body, blown with steam, and the particles are heated and fused together. In order to improve the fusion property between the foamed particles in the method of forming the foam and integrating with the skin, and then cooling to obtain a foam molded body covered with the skin, a pipe for supplying steam into the hollow molded body Patent Document 3 discloses that a (pin) is inserted, steam is supplied from one pipe, discharged from the other pipe, and steam is circulated between the foamed particles to be foamed.

Patent No. 2860007 JP-A-9-280594 JP-A-6-166114

  In the method of Patent Document 1, before cooling and solidifying the hollow molded body, the foam particles are filled into the hollow molded body, steam is blown into the foamed particle molded body, and the foam molded body covered with the skin forms the skin. It is intended to sufficiently fuse the foamed particle molded body and the skin by utilizing the amount of heat possessed by the hollow molded body.

  However, when the thickness of the hollow molded body, which is the skin, is reduced, the heat capacity becomes smaller, so the skin is likely to cool, and its thermal welding power tends to decrease, and the heat capacity to sufficiently heat weld the skin and the foamed particle molded body. In order to obtain the thickness, a skin thickness of 3.5 mm or more is required. When the thickness of the epidermis is thin, that is, when the epidermal thickness is less than 3.5 mm, the adhesive strength between the foamed particle molded body and the epidermis is significantly higher than that having an epidermis with a thickness of 3.5 mm or more. Tended to be lower. If the adhesive strength between the skin and the foamed particle molded body is not sufficient, if the skin-covered foamed molded body is subjected to a large deformation, it will easily peel off at the interface between the skin and the foamed particle molded body, and both will adhere firmly. Bending strength and bending rigidity are greatly reduced as compared with the case of the above.

  In the case of a skin-coated foamed molded article having a thick skin, a high-strength product having good adhesion between the foamed particle molded article and the skin is obtained, but a molded article having a thick skin is heavy. When the skin is made thin in consideration of lightness, as described above, the adhesive strength between the foamed particle molded body and the skin is remarkably lowered, and the foam molded body covered with the skin having sufficiently high adhesive strength and high product strength. The actual situation is not obtained, and there remains a problem in terms of both lightness and adhesive strength between the foamed particle molded body and the skin.

  On the other hand, Patent Document 2 has a description that a molded body in which the foam particles are mutually bonded and the foam particles and the skin are fused is obtained. However, the molding conditions and the like are not particularly disclosed in Patent Document 2, and it is understood that the method is the same as the conventional method for producing a foam molded body covered with a skin by a blow molding method. Molding verification was performed under the same molding conditions as in the prior art. However, when the thickness of the skin is thin, the amount of heat of the skin is insufficient, and sufficient adhesive force cannot be obtained between the foamed particle molded body and the skin. Here, in order to increase the fusion force between the skin and the foamed particle molded body, simply increasing the temperature of the steam not only lowers the adhesive force between the foamed particle molded body and the skin, but depending on the part, The phenomenon that the fusing itself worsens occurred. If the product itself has a simple shape and bending rigidity and bending strength are not so required, the fusion between the foam particles and the fusion between the skin and the molded foam particles are insufficient. However, in applications where bending rigidity and bending strength are required, for example, in applications such as bath lids, the adhesiveness between the expanded particles, the expanded particle molded body and the skin Improvement of the fusing property is desired.

  Furthermore, the method described in Patent Document 3 was verified whether the fusion between the skin and the foamed particle molded body could be improved. When the thickness of the skin was thin, the skin and the foamed particle molded body were Only a skin-coated foamed molded article having a weak adhesive strength was obtained. Further, in the case of a product having a thin skin and a relatively thin molded product, the reduction in adhesive strength was significant.

  The present invention is to fill a hollow molded body molded by a blow molding method with foamed particles, fuse the foamed particles together to form a foamed particle molded body, and further, an inner surface of the skin composed of the hollow molded body, the foamed particle molded body, In a foam-coated foam molded body in which the thickness of the skin is conventionally thin, the foam-coated molded body covered with the skin, which is integrally fused (hereinafter sometimes referred to as “skin-coated foam molded body”). An object of the present invention is to provide a method for producing a skin-coated polystyrene-based resin foam molded article that has solved the problem of adhesion between the skin and the foamed particle molded article that has not been sufficiently achieved. Further, the present invention provides a skin and foamed particle molding that has not been obtained in the past, and is a skin-coated foamed molded product having a thin skin, particularly a skin-coated foamed molded product having a relatively thin thickness. An object of the present invention is to provide a skin-coated polystyrene-based resin foam particle molded body that adheres firmly to the body and is excellent in the fusion property between foam particles and the appearance of the molded body.

  In molding of a skin-coated foamed molded article in which foamed particles are filled into a hollow molded body by conventional blow molding and steam is supplied to fuse the foamed particles together, the heating conditions for the foamed particles are, for example, the above-mentioned Patent Document 1 3, steam of 0.01 to 0.12 MPa (G) is supplied. However, when heated with such steam, when the skin is a thin skin-coated foamed molded article, the foam particles adhere to each other, but the adhesion between the skin and the foamed particle molded article is sufficiently strong. I can't.

  The inventors of the present invention have made various studies on the thermoforming conditions for the production of a skin-coated styrenic resin foam molded body covered with a skin formed by blow molding. In addition to controlling the mold temperature at the time of mold clamping to a specific temperature and molding polystyrene resin expanded particles, it supplies steam at a high temperature that deviates from the heating temperature range generally used in the past. By controlling the steam temperature at the steam supply port and the steam temperature at the discharge port to a specific temperature and performing heat molding, in a skin-covered foamed molded product that has not been achieved under conventional molding conditions, In addition to excellent fusion between the foam particles, the skin with excellent fusion between the molded foam particle and the skin and excellent surface properties. It found that covering the foamed molded product is obtained.

  The present invention is (1) hanging a parison made of polystyrene resin between molds that can be divided, mold the hollow mold by clamping the mold and blow molding the parison, Polystyrene resin foam particles are filled into the hollow molded body, and steam is supplied from and discharged from a plurality of steam supply / discharge pins inserted into the hollow molded body to heat the foamed particles to fuse the foamed particles with each other. A method for producing a foamed molded article covered with a skin made of a hollow molded article, wherein the molded resin foamed molded article is molded and the inner surface of the hollow molded article and the foamed particulate molded article are fused and integrated. The mold temperature at this time is set to a temperature of [glass transition temperature of the base resin of the hollow molded body−30 ° C.] to [glass transition temperature of the base resin of the hollow molded body + 30 ° C.], and one of the plurality of pins is The steam supply side is the steam discharge side, and the steam temperature T1 at the steam supply port of the pin on the steam supply side is the glass transition temperature of the base resin of the foam particles + 10 ° C. to the glass transition of the base resin of the foam particles And a steam temperature T2 at the steam discharge port of the pin on the steam discharge side is controlled to be equal to or higher than [the glass transition temperature of the base resin of the foamed particles −5 ° C.] and heated. A method for producing a polystyrene resin foam molded article.

(2) the production method of the above (1) skin covered polystyrene type resin foamed molded article, wherein the blowing agent content of the polystyrene resin foamed beads are foamed particles 1 m ³ per 60～250G.

(3) The skin-coated polystyrene resin according to (1) or (2), wherein the steam in the hollow molded body is sucked from a pin on the steam discharge side at −0.09 to −0.06 MPa (G). A method for producing a foam molded article.

(4) The production of the skin-coated polystyrene-based resin foam molded article according to any one of (1) to (3) above, wherein a bulk density of the polystyrene-based resin foam particles is 15 to 40 kg / m ^3. Method.

(5) The skin-coated polystyrene-based resin foam molding according to any one of (1) to (4) above, wherein an average thickness of the skin made of the hollow molded body is 0.5 mm or more and less than 3.5 mm Body manufacturing method.

(6) The skin-coated polystyrene-based resin foam molding according to any one of (1) to (5) above, wherein the foamed molded article has a specific surface area of 0.4 to 1.5 cm ² / cm ^3. Body manufacturing method.

(7) The said (6) description characterized by inserting the said pin into a hollow molded object from the both sides | surfaces which a hollow molded object periphery opposes, and making the other side into the steam discharge side. A method for producing a surface-coated polystyrene-based resin foam molded article.

Further, (8) a skin-coated polystyrene-based resin foam molded article comprising a polystyrene-based resin foam molded article and a skin made of a polystyrene resin hollow molded article covering substantially the entire surface of the foamed particle molded article. A skin-coated polystyrene-based resin foam molded article characterized by having an average thickness of 0.5 mm or more and less than 3.5 mm and a material destruction rate of the foamed particle molded article in the skin peel test of 30% or more.

(9) The surface-coated polystyrene-based resin foam molded article according to (8) above, wherein the foam molded article has a specific surface area of 0.4 to 1.5 cm ² / cm ³ .
Is the gist.

  According to the production method of the present invention, by setting the mold temperature at the time of clamping the blow mold to the temperature range of [glass transition temperature-30 ° C.] to [glass transition temperature + 30 ° C.] of the skin base resin, In the mold, the temperature of the skin is kept as high as possible. Furthermore, when foamed particles are formed, the foam particles are filled with steam at a high temperature that is unthinkable in ordinary polystyrene resin foam particle molding. The steam temperature T1 at the steam supply port is [glass transition temperature + 10 ° C.] to [glass transition temperature + 30 ° C.] of the expanded particle base resin, and the steam temperature T2 at the steam discharge port is the expanded particle base resin. The high temperature steam is made to reach the epidermis by rapidly circulating the high temperature steam in the hollow molded body so that the [glass transition temperature of -5 ° C.] or higher. Even if the inner surface of the hollow molded body is in a molten state and the skin of the skin-coated foamed particle molded body is thin, sufficient adhesion strength between the inner surface of the hollow molded body that forms the skin and the foamed particle molded body is achieved. In addition, a skin-covered foamed molded article that secures the fusion between the foamed particles can be obtained.

In addition, the skin-coated polystyrene-based resin foam molded article of the present invention has not been obtained in the past, although the average thickness of the skin made of a polystyrene-based resin hollow molded article is as thin as 0.5 mm or more and less than 3.5 mm, Since it is a skin-covered foamed molded product in which the skin and the polystyrene-based resin foamed particle molded product positioned inside the skin are firmly bonded, the foamed molded product is excellent in bending strength and bending rigidity while being excellent in light weight. In particular, a skin coating that has sufficient bending strength and bending rigidity even in a skin-coated foamed molded article having a specific surface area of 0.4 to 1.5 cm ² / cm ³ , which tends to be low in bending physical properties, that is, relatively thin. It becomes a foaming molding.

  In the production method of the present invention, foamed particles are filled into a hollow molded body formed by conventional blow molding, and then steam is supplied into the hollow molded body so that the foamed particles are fused with each other to be fused and integrated with the skin. When manufacturing a skin-covered foamed molded product, the mold temperature during mold clamping when forming a hollow molded product by blow molding is controlled to a specific temperature, and a conventional skin-coated polystyrene-based resin foamed molded product Steam with a temperature higher than the temperature applied in the molding is supplied into the hollow molded body, and the steam temperature T1 at the steam supply port and the steam temperature T2 at the steam discharge port are controlled to be in a specific temperature range, and the heat molding is performed. This is a method for producing a skin-coated foamed molded article. With the production method of the present invention, even in a skin-coated foamed particle molded body with a thin skin, which has been extremely difficult to produce so far, it has excellent fusion properties between the foamed particles, and the foamed particle molded body and the skin. A skin-coated foamed particle molded article having excellent fusion properties with the above can be obtained.

  More specifically, the mold temperature at the time of mold clamping when molding the hollow molded body is set to [glass transition temperature of the base resin of the hollow molded body -30 ° C] to [glass of the base resin of the hollow molded body]. Transition temperature + 30 ° C.], one of a plurality of steam supply / discharge pins (hereinafter simply referred to as “steam pins”) inserted into the hollow molded body, and the other as the steam discharge side. Also, high temperature (high pressure) steam is supplied, and the steam temperature T1 at the steam supply port of the steam pin is [glass transition temperature of base resin of foamed particles + 10 ° C.] to [glass transition temperature of base resin of foamed particles + 30 ° C.] In addition, the steam temperature T2 at the steam outlet of the steam pin is controlled to a temperature higher than that of the conventional glass transition temperature −5 ° C. of the base resin of the expanded particles, and is heated. In the present invention, the steam supply / discharge pin means a pin used for supplying steam into the hollow molded body, discharging steam from the hollow molded body, or both.

  In the present invention, heating by steam is performed by supplying steam from the supply side and opening the discharge side or suctioning from the discharge side, with one of the plurality of steam pins inserted into the hollow molded body as the supply side and the other as the discharge side. Is done by doing As a heating method, the supply side and the discharge side are fixed and heating is performed only from one direction. Alternatively, one side is the supply side and the other is the discharge side. Either of the alternating heating methods that alternately perform steam heating can be employed, but the alternate heating method is preferable in order to fuse the expanded particles more firmly. In the case of employing the alternate heating method, the first heating is important for fusing the skin and the foamed particle compact, so that T1 and T2 are within the above temperature range during the first heating. What is necessary is just to be satisfied, and the second and subsequent steam heating conditions may be appropriately determined according to the fusion state of the expanded particles.

Usually, high-pressure steam is decompressed and adjusted to a desired pressure in a steam chamber, and the steam whose pressure has been adjusted is supplied into a hollow molded body through a steam pin. Immediately after the start of steam supply, the pressure in the hollow molded body is close to normal pressure, so even if high pressure steam (pressure in the steam chamber) is supplied, the steam pressure drops when supplied into the hollow molded body. Therefore, the temperature of the steam actually supplied into the hollow molded body is low. By continuing the steam supply, the pressure in the hollow molded body increases, and it becomes possible to supply high-temperature steam into the hollow molded body. Further, when the temperature exceeds a specific temperature, the foamed particles undergo secondary foaming and the pressure in the hollow molded body further increases, so that higher temperature steam can be supplied.
At this time, when the steam is not discharged or when the discharge amount is too small with respect to the steam supply amount, or when the secondary foaming force of the foamed particles is too high, the gap through which the steam flows becomes small, and the steam cannot be discharged or the discharge amount is low. When it becomes too small, the pressure in the hollow molded body rises quickly, so that high-temperature steam can be supplied into the hollow molded body, but this high-temperature steam cannot be circulated throughout the hollow molded body. On the other hand, when the discharge amount is too large, the pressure in the hollow molded body cannot be increased, and the steam supply temperature actually supplied into the hollow molded body cannot be increased. Therefore, it is important to balance the supply amount and discharge amount of steam in order to supply and sufficiently distribute high-temperature steam into the hollow molded body.

  In the present invention, the steam temperature at the steam supply port of the steam pin means the temperature of the steam that is actually supplied into the hollow molded body, and the maximum temperature of the steam at the steam supply port during the steam supply is T1. . When there are a plurality of supply-side steam pins, the steam temperature T1 needs to be within the above range at the supply ports of all the steam pins.

  On the other hand, the steam temperature at the steam outlet of the steam pin means the temperature of the steam when the steam is actually discharged from the hollow molded body, and the maximum temperature of the steam at the steam outlet during the steam supply is T2. To do. Here, T2 being equal to or higher than [Glass transition temperature of the foamed particle base resin −5 ° C.] means that high-temperature steam is rapidly flowing between the foamed particles in the hollow molded body. If T2 is low in a specific steam pin, the adhesive force between the skin and the foamed particle molded body is low around the steam pin. Therefore, when there are a plurality of discharge-side steam pins, the steam temperature T2 needs to be within the above range at the discharge ports of all the steam pins.

  The glass transition temperature in the present invention is an intermediate glass transition measured by adopting “when measuring the glass transition temperature after performing a certain heat treatment” as a test piece condition adjustment based on JIS K7121-1987. It means temperature. As a test piece for determining the glass transition temperature, a resin pellet obtained by removing a foaming agent, a plasticizer, or the like from resin pellets or foamed particles for a hollow molded body by a solvent dissolution method or the like is used. As a measuring device, DSCQ1000 manufactured by TA Instruments Inc. can be used.

  In the present invention, the location and direction of insertion of the steam pin into the hollow molded body are not particularly limited, but the entire inner surface side of the hollow molded body and the entire foamed particles in the hollow molded body are uniformly heated by steam. Thus, according to the shape of a hollow molded object, the location and insertion direction to insert in a hollow molded object are determined suitably. When the insertion trace of the steam pin is disliked, it is preferable that the steam pin is inserted in a smaller direction, and the steam pin is preferably inserted from one direction or two directions.

  The schematic diagram explaining the example of arrangement | positioning of a steam pin is shown. In the figure, 1 is a mold, 11 is a mold side surface, 12 is a molding space, 2 is a steam pin, 21 is a supply side steam pin, and 22 is a discharge side steam pin. When inserting the steam pin from one direction of the mold, insert the steam pin from the side of the mold as shown in FIG. 1, or one mold surface of the split mold as shown in FIG. 2 or FIG. A steam pin can be inserted. When inserting the steam pins from two directions, for example, as shown in FIG. 4, the steam pins can be inserted from both side surfaces of the mold with the steam pins facing each other. Although not shown, the steam pins can be inserted with the steam pins facing each other from both mold surfaces.

  FIG. 1 shows an example in which a steam pin is inserted from one side of the mold. FIG. 1 shows an example in which supply-side steam pins 21 and discharge-side steam pins 22 are alternately arranged. FIG. 1 (1) shows an external perspective view, and FIG. 1 (2) shows a front view. FIG. 1 (3) is a cross-sectional view taken along line B-B in FIG. 1 (2), in which supply side steam pins 21 and discharge side steam pins 22 are alternately arranged on one side surface of the mold. Indicates. FIG. 1 (4) shows a cross-sectional view taken along line AA in FIG. 1 (1) (cross section at the parting part of the mold).

  2 and 3 are examples showing a state where a steam pin is inserted from one mold surface of the split mold. FIG. 2 is an example in which the supply-side steam pins 21 and the discharge-side steam pins 22 are alternately arranged for each column, FIG. 2 (1) shows an external perspective view, and FIG. 2 (2) shows FIG. Sectional view taken along line A1-A1 in 1) is shown. FIG. 2 (3) is a cross-sectional view taken along line B1-B1 in FIG. 2 (1). The mold surface (front surface) on the side where the steam pin is inserted is shown. Although not shown, the supply-side steam pins and the discharge-side steam pins may be alternately arranged for each row.

  FIG. 3 shows an example in which the steam pins are inserted from one mold surface of the split mold as in FIG. 2, and FIG. 3 shows a checkered pattern of the supply-side steam pins 21 and the discharge-side steam pins 22. Shows an example of alternating arrangement. 3 (1) is an external perspective view, FIG. 3 (2) is a sectional view taken along line A2-A2 in FIG. 3 (1), and FIG. 3 (3) is B2- in FIG. 3 (1). B2 cut sectional drawing is shown.

  In addition, when inserting steam pins from two directions, adjacent steam pins of one of the steam pins may be arranged alternately on the supply side and the discharge side, but from the viewpoint of the distribution of steam As shown in FIG. 4, it is more preferable to insert steam pins from two opposite directions, one side being a supply side steam pin and the other side being a discharge side steam pin. FIG. 4 is an example showing a state where steam pins are inserted from both side surfaces of the mold, FIG. 4 (1) shows an external perspective view, and FIG. 4 (2) shows a front view. 4 (3a) shows a sectional view taken along line B3-B3 in FIG. 4 (2), FIG. 4 (3b) shows a sectional view taken along line CC in FIG. 4 (2), and FIG. ) Shows a cross-sectional view taken along line A3-A3 in FIG. 4A (a cross section at the parting part of the mold).

  From the viewpoint of the distribution efficiency of steam, it is preferable that approximately half of the inserted steam pins are the steam supply side and the remaining approximately half are the steam discharge side. When inserting steam pins from one direction, it is preferable to alternately arrange the supply side and discharge side steam pins as shown in FIG. In particular, when inserting from the mold surface, it is preferable to alternately arrange the supply side and the discharge side for each row as shown in FIG. 2, and to arrange alternately in a checkered pattern as shown in FIG. preferable. In addition, when inserting steam pins from two directions, adjacent steam pins among the steam pins on one side may be arranged alternately on the supply side and the discharge side, but from the viewpoint of steam distribution More preferably, the steam pins are inserted from two opposite directions as shown in FIG. 4 so that one direction side is the supply side and the other side is the discharge side.

  In the method of the present invention, the steam temperature T1 at the steam supply port is controlled to [glass transition temperature of base resin of foamed particles + 10 ° C.] to [glass transition temperature of base resin of foamed particles + 30 ° C.] and steam discharge port In order to control the steam temperature T2 in the above to [Glass transition temperature of the base resin of the foamed particles−5 ° C.] or higher, the polystyrene foamed particles are filled in the conventional polystyrene resin hollow molded body, and steam is supplied. Steam with a higher pressure (higher temperature) than normal steam used when molding the skin-covered foamed molded article is employed. Although it depends on the discharge condition of steam from the hollow molded body, T1 and T2 can be easily controlled within the above range. Therefore, in the steam chamber, [glass transition temperature of base resin of foamed particles + 22 ° C.] to [of foamed particles] It is preferable to supply steam adjusted to a temperature range of the glass transition temperature of the base resin + 37 ° C.]. For example, when using expanded particles whose base resin is polystyrene having a glass transition temperature of 105 ° C., the steam in the steam chamber has a temperature of 127 ° C. to 142 ° C., that is, the steam pressure is 0.15 to 0.28 MPa, The steam pressure is higher than the pressure 0.01 to 0.12 MPa of steam used in the conventional manufacturing method.

  In ordinary in-mold molding of polystyrene resin foam particles, if high temperature steam is used, the surface of the foam particle molded body becomes rough and rough, and the product appearance is remarkably deteriorated. Steam is never used. On the other hand, in the skin-coated foamed molded article produced in the present invention, since the substantially entire surface of the foamed particle molded body is covered with the skin, the surface roughness of the foamed particle molded body does not appear directly on the product surface. The foamed particles can be formed by high-temperature steam.

  When the steam temperature T1 at the steam supply port, that is, the actual steam temperature supplied into the hollow molded body is less than [glass transition temperature of base resin of foamed particles + 10 ° C.], the average thickness of the skin is less than 3.5 mm. If so, the skin and the foamed particle molded body cannot be firmly bonded. In order to fuse the outer skin and the foamed particle molded body more firmly, T1 is preferably [glass transition temperature of base resin of foamed particles + 12 ° C.] or higher, and [glass of base resin of foamed particles] Transition temperature + 15 ° C.] or more.

  On the other hand, at a steam heating temperature at which the T1 exceeds [Glass transition temperature of the base resin of the expanded particles + 30 ° C.], phenomena such as contraction and melting of the expanded particles occur. In addition, a skin-coated foamed molded article with good dimensional accuracy cannot be obtained. Furthermore, if T1 is too high, the secondary foaming speed of the foamed particles becomes too high, and there is no space for steam to flow between the foamed particles, so that high-temperature steam cannot be circulated to the skin. In addition to being unable to firmly bond the body, depending on the part, the fusion between the foamed particles may also deteriorate. From this point of view, T1 is preferably [Glass transition temperature of base resin of foamed particles + 28 ° C.] or less, and more preferably [Glass transition temperature of base resin of foamed particles + 25 ° C.] or less. .

  In the present invention, a plurality of steam pins are inserted into a hollow molded body, steam is supplied from one pin, discharged from the other pin, and steam is circulated between the expanded particles to expand the expanded particles to secondary expanded fusion. At the time of deposition, the steam temperature T2 at the steam discharge port is set to [glass transition temperature of base resin of foamed particles −5 ° C.] or higher. T1 satisfies the above range, but T2 is less than [Glass transition temperature of base resin of foamed particles−5 ° C.], which means that high-temperature steam is difficult to circulate on the discharge-side steam pins and the inner surface of the skin. Means that If T2 is too low, the fusion between the foamed particles located in the vicinity of the discharge side steam pin and the adhesive force between the skin and the foamed particle molded body are lowered. From this point of view, T2 is preferably controlled to be heated to [glass transition temperature of base resin of foamed particles −2 ° C.] or higher, more preferably [glass transition temperature of base resin of foamed particles] or higher. . Normally, T2 does not exceed T1.

In order to control T2 within the above range while keeping T1 within the above range, it is possible to supply the above-described high-pressure steam into the hollow molded body and employ one or more methods selected from the following means: is necessary.
[A] Increase the steam flow rate.
[B] Use expanded particles having a low secondary expansion capability.
It is preferable to combine the methods [a] and [b] because T1 and T2 can be efficiently controlled and the obtained surface-coated foamed molded article has excellent mechanical properties.

  In order to increase the steam flow rate of the above [a], specifically, a method of sucking the hollow molded body using a vacuum pump or the like can be employed. For example, when supplying high-temperature (high-pressure) steam as described above, it is preferable to discharge the steam at a suction pressure of −0.09 to −0.06 MPa (G).

Furthermore, the method of making the cross-sectional area of the supply port of a steam pin small is mentioned. In order to increase the flow rate of steam, the opening area of the supply port per steam pin is preferably 2 cm ² / line or less. In particular, since the supply amount of steam and steam flow rate is easily adjusted, the opening area is more preferably 0.2~1.8cm ² / present, 0.4~1.4cm ² / this is more preferable.

  When the steam pin insertion direction is one direction, it is only necessary to have a supply port and / or a discharge port only on the side surface of the steam pin, but when the steam pin insertion direction is two opposite directions, It is preferable to have a supply port and / or a discharge port not only on the side but also on the tip of the pin.

  In the present invention, the inner diameter of the steam pin is preferably 1.5 to 6.0 mm, and more preferably 2.0 to 4.0 mm because the steam supply amount, the steam discharge amount, and the steam flow rate can be easily adjusted. On the other hand, if the outer diameter of the steam pin is too small, the inner diameter of the steam pin is reduced, and the steam supply amount and the steam discharge amount are likely to be reduced. Therefore, T1 and T2 may not be achieved. Although it depends on the material of the steam pin, for example, when the steam pin is a steel pipe, the thickness of the steam pin is required to be approximately 2 mm or more in order to ensure the necessary strength when molding the skin-covered foamed molded product. Therefore, the diameter of the steam pin is preferably 5.5 mm or more, and more preferably 6 mm or more. On the other hand, if the diameter is too large, the trace of the steam pin becomes large on the surface of the molded body, which is disadvantageous in terms of design. Therefore, the outer diameter of the steam pin is preferably 15 mm or less, more preferably 10 mm or less. preferable.

As a method for suppressing the secondary foaming ability of the foamed particles of [b] above, for example, a method using foamed particles having a small foaming agent content can be exemplified. The blowing agent content of the foamed particle, contains less than the content in the foamed particles used in ordinary general, i.e. it is preferred to use the expanded beads is adjusted to foamed particles 1 m ³ per 60～250G. A typical general, the blowing agent content is foamed particles are used in excess of foamed particles 1 m ³ per 300 g, by using a blowing agent content is less expanded particles using a hot steam of the present invention Under the molding conditions, the balance between the secondary foaming capacity of the foamed particles and the final secondary foaming ratio is particularly excellent, so that it is easy to achieve the temperature range of T1 and T2 above, It can be sufficiently fused, and the skin and the foamed particle molded body can be sufficiently fused.

  In addition, a foamed particle whose molecular weight near the surface of the foamed particle is adjusted to be relatively high by a method such as a seed polymerization method, a foamed particle whose surface is coated with liquid paraffin or glycerin tristearate, etc. Even when foamed particles having a number of mesh-shaped depressions on the surface of the foamed particles as proposed in 2007-283302 are used, the secondary foaming ability of the foamed particles can be suppressed.

The use of foamed particles that suppress the secondary foaming speed is advantageous in terms of design because T1 and T2 can be within the temperature range without extremely narrowing the space between the steam pins. . Furthermore, since the foamed molded product itself is a thin product, for example, a thin product having a specific surface area (surface area [cm ² ] / volume [cm ³ ]) of 0.4 or more, the insertion position of the steam pin is limited. Thus, even when it is difficult to reduce the distance between the steam pins, there is an advantage that the steam can surely reach the discharge side pin and T2 can be controlled within the above range. From this standpoint, the blowing agent content of the foam particles, more preferably 80~240g per expanded particles 1 m ^3, more preferably from 100~200g per foam particles 1 m ^3.

  In the present invention, the content of the foaming agent in the foamed particles is the same as the foaming agent present in the foamed particles by heating the foamed particles for 30 minutes in an atmosphere of [glass transition temperature of the base resin of the foamed particles + 5 ° C.]. It is a value obtained by diffusing and finding the weight loss. Specifically, first, the weight (W1) is measured using an appropriate amount of foamed particles as a sample. Subsequently, this sample is heated for 30 minutes in an oven adjusted to a temperature of [glass transition temperature of base resin of foamed particles + 5 ° C.]. After the heating is completed, the sample is taken out of the oven and the weight (W2) is measured again. The weight reduction in the oven is determined by subtracting W2 from W1, and the foaming agent content per unit weight in the expanded particles is determined by dividing the value by W1. By multiplying this value by the apparent density of the foamed particles obtained in advance, the content of the foaming agent per unit volume in the foamed particles can be obtained. As a heating apparatus, Tabai Co., Ltd. gear oven GPH-200 etc. can be used.

  Examples of the coating agent include liquid paraffin, glycerol diacetomonolaurate, glycerol tristearate, di-2-ethylhexyl phthalate, di-2-ethylhexyl adipate, and the like. The coating agent can be added during styrene resin particle polymerization or pre-foaming.

In order to further increase the adhesive force between the skin and the foamed particle molded body, when the specific surface area of the produced skin-coated foamed particle molded body is large, particularly when the specific surface area is 0.4 cm ² / cm ³ or more. The steam pin is preferably inserted into the hollow molded body from the peripheral side surface of the hollow molded body, that is, from the side surface of the mold. Further, it is more preferable to insert the steam pins into the hollow molded body from opposite side surfaces of the periphery of the hollow molded body, that is, from both side surfaces of the mold, and to set the one side to the steam supply side and the other side to the steam discharge side. preferable. Furthermore, the distance between the supply side steam pin and the discharge side steam pin is more preferably 400 mm or less. The smaller the distance between the supply-side steam pin and the discharge-side steam pin, the easier it is to control T1 and T2 within the above temperature range, so the distance is more preferably 350 mm or less, and particularly preferably 300 mm or less. .

  On the other hand, since the steam pin insertion trace becomes a void portion, if the distance between the steam pins is too close, the void portion in the skin-covered foamed molded body increases, and the mechanical strength of the molded body decreases. From such a viewpoint, the distance between adjacent supply-side steam pins and discharge-side steam pins is preferably 150 mm or more, more preferably 200 mm or more, and further preferably 250 mm or more.

  In addition, in order to obtain a sufficient adhesive strength between the skin and the foamed particle molded body, when the steam pin is inserted from the side surface of the mold, the distance between the steam pin and the skin on the mold surface side is 50 mm or less. Is preferable, and 30 mm or less is more preferable.

The specific surface area is a value obtained by dividing the surface area [cm ² ] of the skin-covered foam molded article by the volume [cm ³ ] of the molded article, and the larger the value, the thinner the molded article is. Means. In addition, in the case of a molded article having an uneven surface, the surface area is calculated by capturing the surface planarly.
Considering moldability, the lower limit of the specific surface area is about 0.04 cm ² / cm ³ . When used for applications such as a heat insulation panel, the specific surface area is more preferably 0.4 cm ² / cm ³ or more. On the other hand, as the specific surface area increases, that is, as the product thickness of the skin-covered foamed molded product decreases, the production of the skin-covered foamed molded product tends to become difficult, and the upper limit of the specific surface area is approximately 1.5 cm ² / cm. ^{About three} .

  In the present invention, compressed air is blown into the resin parison in the mold to form a hollow molded body, the foamed particles are filled into the hollow molded body, and then steam is introduced into the hollow molded body to cause the foamed particles to secondary foam. In the step of fusing the foam particles, the mold temperature at the time of clamping is set to [Glass transition temperature of the base resin of the hollow molded body -30 ° C] to [Glass transition temperature of the base resin of the hollow molded body + 30 ° C. ], By controlling the temperature within the above range, supplying the above heating conditions, steam at a higher temperature (higher pressure) than conventional, and rapidly circulating the high temperature steam into the hollow molded body. The inner surface of the skin is easily melted by steam, and the adhesion strength between the skin and the foamed particle molded body can be increased, and the fusion property between the foamed particles can be enhanced.

  When the mold temperature at the time of molding the hollow molded body is lower than the [glass transition temperature of the base resin of the hollow molded body −30 ° C.], the inner surface of the hollow molded body cannot be easily melted, so that the skin and the expanded particles The effect of increasing the adhesion with the molded body cannot be obtained, and the adhesion strength between the skin and the foamed particle molded body becomes weak. On the other hand, when the mold temperature is higher than the glass transition temperature of the base resin of the hollow molded body + 30 ° C., the hollow molded body is still in a softened state, so that the hollow molded body is greatly deformed when the steam pin is inserted. Or the foamed particles are melted by the amount of heat of the hollow molded body, which is not preferable because the surface appearance of the molded body is remarkably deteriorated. From this viewpoint, it is preferable that the lower limit of the mold temperature is [glass transition temperature of base resin of hollow molded body −25 ° C.]. On the other hand, the upper limit is preferably [glass transition temperature of base resin of hollow molded body + 10 ° C.], more preferably [glass transition temperature of base resin of hollow molded body], and further preferably [hollow molding]. The glass transition temperature of the body base resin is −10 ° C.].

According to the production method of the present invention, a skin-covered foam in which the skin and the foamed particle molded body are firmly bonded and integrated even when the average thickness of the skin is less than 3.5 mm, which could not be produced conventionally. A molded body can be produced. From the viewpoint of weight reduction, the thinner the average thickness of the epidermis, the better. However, if the average thickness of the epidermis is too thin, there is a possibility that sufficient adhesive strength cannot be obtained between the epidermis and the foamed particle molded body. In addition, there is a possibility that the foamed particle shape is raised on the surface, the appearance of the surface of the molded product is lowered and the designability is impaired, and the practical strength cannot be satisfied. From such a viewpoint, the upper limit of the average thickness of the epidermis is preferably 3 mm or less, more preferably 2.5 mm or less, and the lower limit thereof is preferably 0.5 mm or more, more preferably 0.7 mm or more, More preferably, it is 1 mm or more.
On the other hand, if the skin thickness is 3.5 mm or more, the weight reduction of the product molded body cannot be obtained, but even in the case of 3.5 mm or more, the production method of the present invention allows the skin and the foamed particle molded body to be reduced. However, it is possible to produce a skin-coated foamed molded article that is more firmly bonded than in the past, and it is also possible to shorten the molding cycle as compared with the conventional production method.

  The skin thickness in the present invention means an arithmetic average value of the thickness of the skin at each measurement point by arbitrarily selecting at least 10 measurement points from the skin-coated foamed molded product. However, greatly deformed parts such as ribs and corners are not used as measurement points. The skin thickness can be measured by cutting the skin-covered foam molded body and directly measuring the cross-section of the skin with a thickness gauge, etc., or measuring with an ultrasonic thickness meter without destroying the skin-covered foam molded body. A conventionally known measurement method such as a method for performing the above can be employed.

  Examples of the polystyrene resin used for the hollow molded body forming the skin in the present invention include polystyrene, impact-resistant polystyrene resin (HIPS), styrene-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, and acrylonitrile. -Styrene-acrylate copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), etc. are illustrated. These are used by 1 type, or 2 or more types of mixtures. In addition, for the purpose of improving impact resistance and the like, the polystyrene resin includes styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, and their complete hydrogenated product or partially hydrogenated product. A thermoplastic styrenic elastomer can also be mixed.

  The mold temperature at the time of clamping is determined based on the glass transition temperature of the base resin of the innermost layer when the hollow molded body has a multilayer structure of two or more layers. Furthermore, when two or more kinds of resins are mixed and used as the base resin of the hollow molded body, the resin having the highest mixing ratio is based on the glass transition temperature of the resin having the highest mixing ratio (weight ratio). When there are two or more kinds, the highest glass transition temperature among them is used as a reference. Moreover, when resin used as base resin of a hollow molded object shows two or more glass transition temperatures, the highest glass transition temperature among them is used as a reference.

It is practically preferable that the skin of the skin-coated foamed molded article according to the present invention has a Charpy impact strength (ISO 179) measured by a notched test piece in accordance with JIS K7111, of 4 kJ / m ² or more. In order to ensure the rigidity while adjusting the impact strength within the above range, as the polystyrene resin forming the skin, a polystyrene resin excellent in impact resistance such as impact polystyrene and ABS resin can be used alone. It is preferable to use or use a mixture of general-purpose polystyrene, which is a homopolymer of styrene, with impact-resistant polystyrene and / or thermoplastic styrene elastomer. For example, when impact-resistant polystyrene is mixed with general-purpose polystyrene, the mixing ratio of impact-resistant polystyrene is preferably 30% by weight or more.

  In particular, when the thickness of the skin is as thin as less than 3.5 mm, when the skin-covered foamed molded product is released from the mold, the skin is likely to break, such as cracks. The mixing ratio of impact-resistant polystyrene in the material resin is preferably 40% by weight or more, and more preferably 50% by weight or more.

  On the other hand, when a large hollow molded body is molded or when multiple pieces are taken, if the length of the parison is 1.5 m or more, the drawdown of the parison tends to increase and it becomes difficult to form a hollow molded body. There is a tendency. In order to improve the drawdown property of the parison, it is possible to use, as the general-purpose polystyrene, a general-purpose polystyrene having a long chain branch and a high melt tension, specifically, a general-purpose polystyrene having a melt tension of 20 cN or more at 200 ° C. preferable. By using high-melting-strength general-purpose polystyrene mixed with impact-resistant polystyrene resin, it is possible to effectively improve the drawdown of the parison while maintaining the impact resistance of the desired hollow molded article. . The mixing amount is preferably 20% by weight or more, and more preferably 30% by weight or more. As such high melt tension general-purpose polystyrene, for example, it is commercially available from PS Japan Co., Ltd. as grade names G9401, HH32, and the like.

  Therefore, when the thickness of the epidermis is less than 3.5 mm and the length of the parison is 1.5 m or more, the epidermis base resin is a mixture of high melt tension general-purpose polystyrene and impact polystyrene. The mixing ratio is preferably 60:40 to 20:80, and more preferably 50:50 to 30:70.

  The melt tension is a value measured by Capillograph 1D manufactured by Toyo Seiki Seisakusho Co., Ltd. Specifically, a cylinder having a cylinder diameter of 9.55 mm and a length of 350 mm and an orifice having a nozzle diameter of 2.095 mm and a length of 8.0 mm were used. The required amount is put in the cylinder and left for 4 minutes, and then the molten resin is extruded from the orifice into a string with a piston speed of 10 mm / min, and this string is hung on a tension detection pulley having a diameter of 45 mm. The pulling speed is increased at a constant speed so that the take-up speed reaches 0 m / min to 200 m / min. Get the local maximum. Here, the reason why the time until the take-up speed reaches 0 m / min to 200 m / min is set to 4 minutes is to suppress the thermal deterioration of the resin and increase the reproducibility of the obtained value. Using a different sample for the above operation, measuring a total of 10 times, removing the three values in order from the largest value of the maximum value obtained in 10 times, and the three values in order from the smallest value of the maximum value, The value obtained by arithmetically averaging the remaining four intermediate maximum values is taken as the melt tension (cN) in the method of the present invention.

However, when the melt tension is measured by the method described above and the string-like material is not cut even when the take-up speed reaches 200 m / min, the melt tension obtained by setting the take-up speed to a constant speed of 200 m / min. The value of (cN) is adopted. Specifically, in the same manner as in the above measurement, the molten resin is extruded into a string from the orifice, and this string is put on a tension detection pulley, and a constant speed increase is made so that the speed reaches 0 m / min to 200 m / min in 4 minutes. Rotate the take-up roller while increasing the take-up speed, and wait until the rotation speed reaches 200 m / min. When the rotational speed reaches 200 m / min, the data acquisition of the melt tension is started, and the data acquisition is finished after 30 seconds. The average value (T _ave) of the tension maximum value (T _max ) and the tension minimum value (T _min ) obtained from the tension load curve obtained during this 30 seconds is taken as the melt tension in the method of the present invention. Here, the T _max is a value obtained by dividing the total value of the detected peak (peak) values in the tension load curve by the number detected, and the T _min is the tension load curve. This is a value obtained by dividing the total value of detected dip (valley) values by the number of detected values.
Of course, when the molten resin is extruded from the orifice into a string shape in the above measurement, bubbles are prevented from entering the string as much as possible.

In the present invention, the bulk density of the expanded particles is not particularly limited, and generally used expanded particles having a bulk density of 10 to 100 kg / m ³ can be used, but the secondary foaming ability can be more easily controlled by steam. becomes therefore, the bulk density of the expanded beads is preferably from 15~40kg / ^{m 3,} more preferably 15~30kg / ^{m 3.}

  As a method for producing the expanded particles in the present invention, a generally used method for producing expanded particles is applied. For example, in an airtight container, an aromatic vinyl monomer such as styrene is stirred and dispersed together with a suspending agent in an aqueous medium to perform suspension polymerization, and during or after the suspension, a foaming agent such as an aliphatic hydrocarbon or a plasticizer It is possible to produce expandable styrene resin particles by impregnating them. The foamable polystyrene resin particles are heated and foamed to obtain foamed particles having a required foaming density.

  As a styrene resin which is a base resin of styrene resin expanded particles used in the production method of the present invention, a homopolymer of an aromatic vinyl monomer or a copolymer of two or more aromatic vinyl monomers, A copolymer of more than 50% by weight of an aromatic vinyl monomer and a comonomer component other than an aromatic vinyl monomer of less than 50% by weight copolymerizable with the monomer, and not only the homopolymer or the copolymer And derivatives of these polymers. In addition, it is preferable that the ratio of the aromatic vinyl-type monomer component unit in the said styrene-type resin is 60 to 100 weight%, and it is more preferable that it is 70 to 100 weight%. In such a case, the physical properties are excellent in uniformity.

  Examples of the aromatic vinyl monomer include styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, vinyl toluene, p-ethyl styrene, 2,4-dimethyl styrene, p-methoxy. Styrene, p-phenylstyrene, pn-butylstyrene, pn-hexylstyrene, p-octylstyrene, pt-butylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2, Examples include 4-dichlorostyrene, 2,4,6-tribromostyrene, styrene sulfonic acid, sodium styrene sulfonate, and the like. Moreover, as comonomer components other than said aromatic vinyl-type monomer, carbon number of acrylic acid, such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylate-2-ethylhexyl, is 1-10. Alkyl ester; alkyl ester having 1 to 10 carbon atoms of methacrylic acid such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate; containing nitrile groups such as acrylonitrile and methacrylonitrile And unsaturated compounds.

  The ratio of the styrene component unit is 60 to 100% by weight from the standpoint of excellent foamability, excellent in-mold moldability of the resulting foamed particles, versatility, and the like. It is more preferable that it is 70 to 100% by weight.

  When two or more kinds of foam particles having different base resin are mixed and used as the foam particles, the temperature of steam supplied to the hollow molded body (temperature in the chamber) and the temperatures of T1 and T2 are determined. When there are two or more types of expanded particles having the highest mixing ratio based on the glass transition temperature of the base resin of the expanded particles having the highest mixing ratio (weight ratio), the lowest glass among them Based on the transition temperature. In addition, when the base resin of the expanded particles exhibits two or more glass transition temperatures, the highest glass transition temperature among them is used as a reference.

  As a preferable particle diameter range of the styrene resin expanded particles used in the production method of the present invention, 1.0 to 3.5 mm is preferable, and 1.5 to 3.2 mm is more preferable. When the particle diameter of the expanded particles is in the above range, the obtained molded product has excellent mechanical properties, and also has excellent filling properties of the expanded particles into the details and thin parts of the hollow molded product at the time of molding. Become.

  In the present invention, any method can be adopted as a method of adjusting the foaming agent content in the foamed particles to a smaller amount than that of normal polystyrene resin foamed particles, that is, the foaming agent content in the foamed particles within the above range. . For example, foamable resin particles containing a conventional amount of foaming agent are heated and foamed to form foamed particles, and then stored in a breathable container until the foaming agent is dissipated from the foamed particles and reduced to a predetermined amount. By adjusting the foaming agent content by adjusting the foaming agent amount to a smaller amount than before when producing foamable resin particles, and producing foamable resin particles with a low foaming agent content. In addition, there is a method of obtaining foamed particles in which the foaming agent content is adjusted to be small by pre-foaming to a predetermined foaming ratio with high-temperature steam. Among these methods, since the mechanical strength of the final skin-coated foamed molded article will be excellent, the foaming agent is contained by storing the foaming agent by evacuating the foaming agent and reducing it to a predetermined amount. A method of adjusting the amount to a small amount is preferable.

  The foaming agent used in the production of the expanded particles in the present invention is a hydrocarbon such as propane, normal butane, isobutane, pentane, cyclopentane, methyl chloride, ethyl chloride, which is used in the production of conventional polystyrene-based resin expanded particles. Inorganic gases such as chlorinated hydrocarbons such as air, carbon dioxide and nitrogen can be used. Among these foaming agents, use of hydrocarbons such as normal butane, isobutane, pentane, and cyclopentane is preferable because the residual foam content in the foamed particles can be easily controlled.

  If the adhesive strength between the skin and the foamed particle molded body is inadequate, the mechanical strength of the molded body, particularly bending rigidity and bending strength, will be low, so that the applications that can be used will be limited and the practicality will be poor. . Therefore, when the skin-covered foamed molded product having a thin skin and a thin molded product itself is used for applications requiring high mechanical strength, such as a bath lid, Must be firmly bonded. If the adhesion between the two is insufficient, interface peeling occurs at the interface between the skin and the foamed particle molded body. On the other hand, if the two are sufficiently fused, the adhesive strength between the two exceeds the material strength of the foamed particles or the adhesive strength between the foamed particles of the foamed particle molded product. Or, material destruction of the expanded particles occurs. From the viewpoint of sufficient adhesive strength, in the skin peeling test in which the skin and the foamed particle molded body are peeled, it is desirable that the foamed particle molded body breaks the material, and the foamed particle molded body has a material fracture rate of 30% or more. More preferably, it is 50% or more, More preferably, it is 70% or more. In the present invention, both peeling between the expanded particles or material destruction of the expanded particles are collectively referred to as “material destruction” of the expanded particle molded body.

Although the material destruction depends on the apparent density of the foamed particle molded body, it occurs when the adhesive strength between the skin and the foamed particle molded body is approximately 0.2 kgf / cm ² or more. it is preferred that the adhesive strength between the at 0.2 kgf / cm ² or more, more preferably 0.3 kgf / cm ² or more, further preferably 0.4 kgf / cm ² or more. Since the mechanical strength of the foamed particle molded body is rate-determining, the upper limit of the adhesive strength is about 1.2 kgf / cm ² when the skin and the foamed particle molded body are completely fused.

In the present invention, a skin peel test for evaluating the adhesion between the skin and the foamed particle molded body is performed as follows. As a test piece for measurement, it is cut out from the skin-coated foamed molded product into 50 mm × 50 mm × (molded product thickness). However, when the thickness of the molded body exceeds 200 mm, a test piece is cut out from the skin up to 200 mm in the thickness direction. The upper and lower surfaces of the test piece are firmly adhered to an adhesive strength measuring jig with an adhesive, and a tensile test is performed at a tensile speed of 10 mm / min using a measuring device such as a tensile strength tester Tensilon. At this time, subtract the area of the part where the skin and the foamed particle molded body were peeled from the interface from the total surface area on the adhesive surface side of the skin, and divide that value by the total surface area on the adhesive surface side of the skin, The material destruction rate (%) of the foamed particle molded body in the test is used. Moreover, let the maximum point stress at the time of a skin peeling test be adhesive strength (kgf / cm < ² >).

Foaming apparent density of the grain compact constituting the skin covered foamed molded article of the present invention is preferably 15~40kg / ^{m 3,} more preferably 15~30kg / ^{m 3.} When the apparent density of the foamed particle molded body is within the above range, the skin-covered foamed molded body has both practical strength and light weight.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the evaluation result shown in this invention shows the effect of this invention relatively by contrast with a comparative example, and this invention is not limited to an Example.

[Thickness of skin]
The skin thickness of the skin-coated foamed molded product was determined by the following method. On the plate surface of the obtained skin-covered foamed molded product, arbitrary 10 points were selected as measurement points from the inner part of the plate surface at least 50 mm from the outer periphery of the plate surface, and an ultrasonic thickness meter (model: TI-65W) manufactured by JFE Advantech Co., Ltd. , B probe), the speed of sound was set to 2340 m / sec for polystyrene measurement, and the skin thickness at each measurement point was measured. This measurement was performed on both plate surfaces, and the value obtained by arithmetically averaging the measured values was defined as the thickness [mm] of the skin of the skin-coated foamed molded product.

[Glass-transition temperature]
The glass transition temperature of the hollow molded body base resin and the glass transition temperature of the expanded particle base resin were measured by the following methods based on JIS K7121-1987. First, when measuring the glass transition temperature of the hollow molded body base resin, about 1 g of resin pellets for forming a hollow molded body is measured, and when measuring the glass transition temperature of the foamed particle base resin, about 1 g of expanded particles is 200 ml. Then, 700 ml of methanol was added to the solution to reprecipitate the base resin. The precipitated base resin was separated by filtration and dried at 120 ° C. for 4 hours. After drying, about 10 mg is collected as a measurement sample, and a DSCQ1000 manufactured by TA Instruments is used as a measuring device, under a nitrogen gas flow rate of 30 ml / min, at a heating rate of 10 ° C./min. The temperature was raised to 220 ° C. and held at that temperature for 10 minutes, then cooled to 30 ° C. at a cooling rate of 10 ° C./min to adjust the state of the test piece, and again at 220 ° C. at a heating rate of 20 ° C./min. The DSC curve was obtained. The midpoint glass transition temperature was determined from the DSC curve during the second temperature increase.

[Foaming agent content]
The foaming agent content in the expanded particles was measured by the weight change method described above. A gear oven GPH-200 manufactured by Tabai Co., Ltd. was used as an apparatus. About 2 g of expanded particles were sampled and weighed to the fourth decimal place to determine the initial weight W1 [g]. This sample was placed in an oven with a damper opening degree of 60% and an oven temperature adjusted to [glass transition temperature of base resin of foamed particles + 5 ° C.] and heated for 30 minutes. After heating, the sample was taken out of the oven, the weight was weighed to the fourth decimal place, and the weight W2 [g] after heating was determined. By subtracting W2 from W1, the weight loss [g] in the oven is obtained, the value is divided by W1, and the unit conversion is performed to obtain the foaming agent content [g / kg] per 1 kg of the foam particles. Asked. The foaming agent content [g / m ³ ] per 1 m ³ in the foamed particles was determined by multiplying this value by the apparent density [kg / m ³ ] of the foamed particles obtained in advance.

"Apparent density and bulk density of expanded particles"
The volume: V [L] of the foam particles that can be read from the rise in the water level is measured by sinking the foam particles having a weight of W [g] into a graduated cylinder containing water using a wire mesh. The apparent density [kg / m ³ ] of the expanded particles was determined by dividing the weight of the expanded particles by the volume of the expanded particles (W / V) and converting the unit to [kg / m ³ ]. Further, the bulk density [kg / m ³ ] of the expanded particles was determined by dividing the apparent density by 1.6.

[Measurement method of T1 and T2]
T1 and T2 were measured by the following method. When inserting a steam pin into a hollow molded body, one thermocouple was placed along each steam pin, and the thermocouple was inserted into the hollow molded body to a depth where the tip of the steam pin and the tip of the thermocouple coincided. . With these thermocouples, the temperature change from the start of the first steam heating to the end of heating is measured for each steam pin, and the maximum temperature T1 on the supply side during heating and the maximum reach on the discharge side are measured for each steam pin. The temperature T2 was determined. As described above, for T1, since it is necessary to satisfy [glass transition temperature + 10 ° C.] to [glass transition temperature + 30 ° C.] of the expanded particle base resin in all the supply side steam pins, each steam pin The maximum value and the minimum value of T1 measured in the table are shown in the table. Further, regarding T2, since it is necessary to satisfy the [glass transition temperature of −5 ° C.] or higher of the expanded particle base resin in all the discharge side steam pins, the minimum value of T2 measured in each steam pin is shown in the table. It was described in.

  Hereinafter, the pressure of the steam supplied into the hollow molded body means the steam pressure (gauge pressure) in the steam chamber, and the pressure on the exhaust side means the suction pressure (gauge pressure).

[Styrene resin foam particles]
Expandable polystyrene resin particles containing polystyrene (described as “GP” in the table) as a base resin and containing 1.6% by weight of butane and 1.4% by weight of cyclohexane are pre-expanded under an atmosphere of 102 ° C. Polystyrene foam particles having a density of 21 kg / m ³ and an average particle diameter of 3.1 mm were obtained. By storing the obtained foamed particles at room temperature, the foaming agent in the foamed particles was dissipated to adjust the foaming agent content in the foamed particles.

Example 1
Impact-resistant polystyrene (trade name: PSJ-polystyrene, grade name: H0104, described as “HI1” in the table) manufactured by PS Japan Co., Ltd. and general-purpose polystyrene (trade name: PSJ-polystyrene, grade name: G9401) manufactured by PS Japan Co., Ltd. , Described as “GP1” in the table) at a blending ratio shown in Table 1, supplied to an extruder with an inner diameter of 65 mm, and heated and melted at 185 ° C. to obtain a melt resin for the skin.
Next, the molten resin was filled in an accumulator adjusted to 185 ° C., and the molten resin was extruded from a die connected to the downstream side of the accumulator to form a parison.
Next, the softened parison is located directly under the die, and is a flat plate-shaped split mold adjusted to the temperature shown in Table 1 (dimension molding space dimensions: 190 cm long, 90 cm wide, 4 cm thick) , Specific surface area: 0.53 cm ² / cm ³ ) After mold clamping, pressurized gas (air) is blown into the interior of the parison to form a hollow molded body (skin) with the thickness shown in Table 1 did.

  Next, 40 steam pins having an outer diameter of 10 mm and an inner diameter of 6 mm (wall thickness of 2 mm) are arranged in a 5 × 8 grid pattern in the hollow molded body, and the pitch interval of each steam pin is 200 mm. It was inserted into the hollow molded body from the surface toward the other mold surface to a depth of 35 mm. Next, polystyrene foam particles having a bulk density shown in Table 1 and adjusted to the foaming agent content shown in Table 1 were filled into the hollow molded body as polystyrene-based resin foam particles. The glass transition temperature of the base resin of the expanded particles was 105 ° C. When the foamed particles were filled into the hollow molded body, the foamed particles were filled while discharging air inside the hollow molded body from the steam pin. After the air is discharged, half of the inserted steam pins are arranged in a checkered pattern with the remaining 20 pins as the steam supply side and the remaining 20 pins as the discharge side, and sucked from the discharge side pin at -0.08 MPa (G). While, 0.21 MPa (G) of steam was supplied from the supply-side pin for 15 seconds. At this time, the steam temperature T1 at the steam supply port was 122 ° C. for each steam pin, and the minimum value of the steam temperature T2 at the steam discharge port was 106 ° C. Next, the pin that was supplying steam was the discharge side, and the pin that was discharged was the supply side, while suctioning at −0.08 MPa (G) from the discharge side pin, 0.21 MPa ( G) By supplying steam for 10 seconds, the foamed particles were thermoformed to obtain a foamed particle molded body in which voids between the foamed particles were filled in the hollow molded body and the foamed particles were fused.

  Subsequently, after cooling by suction from the steam pin inserted in the layer of the foamed particle molded body, the mold was opened and the skin-covered foam molded body was taken out. This molded body was cured at 40 ° C. under atmospheric pressure for 24 hours to obtain the intended skin-covered foamed molded body. In the obtained skin-coated foamed molded product, the inner surface of the skin and the foamed particle molded product were firmly fused. Table 1 shows various physical properties such as adhesive strength of the obtained skin-coated foamed molded article.

Example 2
Impact-resistant polystyrene (trade name: PSJ-polystyrene, grade name: H0104, described as “HI1” in the table) manufactured by PS Japan Co., Ltd. and general-purpose polystyrene (trade name: PSJ-polystyrene, grade name: G9401) manufactured by PS Japan Co., Ltd. , Described as “GP1” in the table) at a blending ratio shown in Table 1, supplied to an extruder with an inner diameter of 65 mm, and heated and melted at 185 ° C. to obtain a melt resin for the skin.
Next, the molten resin was filled in an accumulator adjusted to 185 ° C., and the molten resin was extruded from a die connected to the downstream side of the accumulator to form a parison.
Next, the softened parison is located directly under the die and is a flat plate-shaped split mold adjusted to the temperature shown in Table 1 (dimension molding space dimensions: 42 cm long, 73 cm wide, 2 cm thick) , Specific surface area: 1.08 cm ² / cm ³ ), and after mold clamping, pressurized gas (air) is blown into the interior of the parison to form a hollow molded body (skin) with the thickness shown in Table 1 did.

Next, in the hollow molded body, six steam pins each having an outer diameter of 8 mm and an inner diameter of 3 mm (wall thickness: 2.5 mm) from the parting surfaces on both sides of the mold, a total of six, and the pitch interval between adjacent steam pins are set. It was set to 150 mm and inserted into the hollow molded body to a depth of 215 mm toward the opposite side surface, and the mutual distance between the tips of the opposing steam pins was set to 300 mm. Next, polystyrene foam particles having a bulk density shown in Table 1 and adjusted to the foaming agent content shown in Table 1 were filled into the hollow molded body as polystyrene-based resin foam particles. The glass transition temperature of the base resin of the expanded particles was 105 ° C. When filling the foamed particles into the hollow molded body, the foamed particles were filled while discharging air in the hollow molded body from the steam pin. After the air is discharged, among the steam pins inserted into the layer of filled foam particles, the three pins on one side are the supply side and the three pins on the other side are the discharge side and the discharge side While sucking at -0.08 MPa (G) from this pin, steam of 0.21 MPa (G) was supplied from the supply-side pin for 15 seconds. At this time, the steam temperature T1 at the steam supply port of each steam pin was 122 ° C. for each steam pin, and the minimum value of the steam temperature T2 at the discharge port was 106 ° C. Next, the pin that was supplying the steam was the discharge side, the pin that was discharging the steam was the supply side, and the suction side was sucked at -0.08 MPa (G) from the supply side pin, while the suction side was 0. By supplying 21 MPa steam for 8 seconds, the foamed particles were thermoformed to obtain a foamed particle molded body in which voids between the foamed particles were filled in the hollow molded body and the foamed particles were fused.
After cooling, the mold was opened and the skin-covered foamed molded product was taken out. This molded body was cured at 40 ° C. under atmospheric pressure for 24 hours to obtain a skin-coated foamed molded body. In the obtained skin-coated foamed molded product, the inner surface of the skin and the foamed particle molded product were firmly fused. Table 1 shows various physical properties such as adhesive strength of the obtained skin-coated foamed molded article.

Examples 3 and 4
The same impact-resistant polystyrene and general-purpose polystyrene used in Example 2 were dry blended at the blending ratio shown in Table 1, supplied to an extruder having an inner diameter of 65 mm, heated and melted at 185 ° C., and melted for the skin. A skin-coated foamed molded article was obtained in the same manner as in Example 2 except that the resin was used. Table 1 shows various physical properties of the obtained skin-coated foamed molded article.

Example 5
PS Japan Co., Ltd. chemical-resistant impact-resistant polystyrene (trade name: PSJ-polystyrene, grade name: RX100, described as “HI2” in the table) is supplied to an extruder with an inner diameter of 65 mm and melted by heating at 185 ° C. A foamed molded article with a skin was obtained in the same manner as in Example 2 except that the molten resin for the skin was used. Table 1 shows various physical properties of the obtained skin-coated foamed molded article.

Example 6
Asahi Kasei Co., Ltd. acrylonitrile / butadiene / styrene copolymer (trade name: Stylac-ABS, grade name: A4521, described as “ABS1” in the table) is supplied to an extruder with an inner diameter of 65 mm and heated and melted at 230 ° C. Then, a skin-coated foamed molded article was obtained in the same manner as in Example 2 except that the melted resin for the skin was used, and the foamed particles whose foaming agent content was adjusted to 197 g / m ³ were used as the foamed particles. Table 1 shows various physical properties of the obtained foamed product with skin.

Example 7
A skin-coated foamed molded article was obtained in the same manner as in Example 2 except that the average thickness of the skin was 1.0 mm. Table 1 shows various physical properties of the obtained skin-coated foamed molded article.

Example 8
A skin-coated foamed molded article was obtained in the same manner as in Example 2 except that the average thickness of the skin was 2.5 mm. Table 1 shows various physical properties of the obtained skin-coated foamed molded article.

Example 9
A skin-coated foamed molded article was obtained in the same manner as in Example 2 except that foamed particles having a foaming agent content adjusted to 118 g / m ³ were used as the foamed particles. At this time, the minimum value of T2 was 107 ° C. Table 1 shows various physical properties of the obtained skin-coated foamed molded article.

Example 10
A skin-coated foamed molded article was obtained in the same manner as in Example 2 except that foamed particles having a foaming agent content adjusted to 197 g / m ³ were used as the foamed particles. At this time, the minimum value of T2 was 103 ° C. Table 1 shows various physical properties of the obtained skin-coated foamed molded article.

Example 11
Foaming is performed by supplying 0.24 MPa (G) of steam from the supply-side steam pin for 13 seconds, and then supplying 0.24 MPa (G) of steam for 5 seconds with the pin from which steam has been discharged as the supply side. A skin-coated foamed molded article was obtained in the same manner as in Example 2 except that the particles were thermoformed. At this time, T1 was 125 ° C. for each steam pin, and the minimum value of T2 was 109 ° C. Table 1 shows various physical properties of the obtained skin-coated foamed molded article.

Example 12
Foaming is performed by supplying 0.18 MPa (G) steam from the supply side steam pin for 20 seconds, and then supplying 0.18 MPa (G) steam for 12 seconds with the pin from which steam has been discharged as the supply side. A skin-coated foamed molded article was obtained in the same manner as in Example 2 except that the particles were thermoformed. At this time, T1 was 117 ° C. for each steam pin, and the minimum value of T2 was 101 ° C. Table 1 shows various physical properties of the obtained skin-coated foamed molded article.

Example 13
A skin-covered foamed molded article was obtained in the same manner as in Example 2 except that the temperature of the mold was 100 ° C. At this time, T1 was 124 ° C. for each steam pin, and the minimum value of T2 was 106 ° C. Table 1 shows various physical properties of the obtained skin-coated foamed molded article.

Example 14
Example 14 is an example according to the production method of the present invention. A skin-coated foamed molded article was obtained in the same manner as in Example 1 except that the average thickness of the skin was 4.0 mm. Table 1 shows various physical properties of the obtained skin-coated foamed molded article. Compared with the conventional manufacturing method (Reference Example 1), the obtained skin-coated foamed molded article was excellent in adhesion between the skin and the foamed particle molded article, and the molding cycle could be shortened.

Comparative Example 1
0.12 MPa (G) steam was supplied for 15 seconds, and then the foamed particles were thermoformed by supplying 0.12 MPa (G) steam for 10 seconds with the pin from which steam was discharged being the supply side Except for the above, a skin-coated foamed molded article was obtained in the same manner as in Example 1. At this time, T1 was 108 ° C. for each steam pin, and the minimum value of T2 was 86 ° C. Table 2 shows the physical properties of the obtained skin-coated foamed molded article. Since the temperature of T1 was too low, the inside of the skin could not be melted, and only a skin-covered molded body having low adhesive strength between the skin and the foamed particle molded body was obtained.

Comparative Example 2
0.12 MPa (G) steam was supplied for 15 seconds, and then the foamed particles were thermoformed by supplying 0.12 MPa (G) steam for 8 seconds with the pin from which steam was discharged as the supply side Except for the above, a skin-coated foamed molded article was obtained in the same manner as in Example 2. At this time, T1 was 108 ° C. for each steam pin, and the minimum value of T2 was 86 ° C. Table 2 shows the physical properties of the obtained skin-coated foamed molded article. As in Comparative Example 1, since the temperature of T1 was too low, only a skin-covered molded body having a low adhesive strength between the skin and the foamed particle molded body was obtained.

Comparative Example 3
0.30 MPa (G) steam was supplied for 15 seconds, and then the foamed particles were thermoformed by supplying 0.30 MPa (G) steam for 10 seconds with the pin from which steam was discharged being the supply side. Except for the above, molding was performed in the same manner as in Example 2. At this time, T1 was 138 ° C. for each steam pin, and the minimum value of T2 was 109 ° C. The steam temperature was too high, and the foamed particles near the steam pin were melted. At the part away from the steam pin, the adhesion between the skin and the foamed particle molded body and the fusion between the foamed particles were poor. Since a good skin-covered molded article could not be obtained, evaluation of adhesive strength and fusion rate was not performed.

Comparative Example 4
A skin-coated foamed molded article was obtained in the same manner as in Example 2 except that foamed particles having a foaming agent content adjusted to 276 g / m ³ were used as the foamed particles. At this time, T1 was 122 ° C. for each steam pin, and the minimum value of T2 was 94 ° C. Table 2 shows the physical properties of the obtained skin-coated foamed molded article. Since the secondary foaming speed of the foamed particles is too high, high-temperature steam cannot be quickly circulated in the hollow molded body, the adhesive strength between the skin and the foamed particle molded body is low, and the fusion rate between the foamed particles Only a low skin-coated foamed molded product was obtained.

Comparative Example 5
A skin-covered foamed molded article was obtained in the same manner as in Example 2 except that the mold temperature at the time of mold clamping was 60 ° C. (less than the temperature specified in the present invention). Table 2 shows the physical properties of the obtained skin-coated foamed molded article. Since the mold temperature was too low, only a skin-covered molded article having a low adhesive strength between the skin and the foamed particle molded article was obtained.

Comparative Example 6
A skin-covered foamed molded article was obtained in the same manner as in Example 2 except that the mold temperature at the time of mold clamping was 140 ° C. (temperature exceeding the temperature specified in the present invention). Since the mold temperature was too high, the pins did not puncture normally into the epidermis, and the foamed particles could not be filled uniformly, so the physical properties were not evaluated.

Comparative Example 7
While sucking at -0.04 MPa (G) from the discharge side pin, 0.21 MPa (G) steam was supplied for 20 seconds. At this time, the steam temperature T1 at the steam supply port was 123 ° C. for each steam pin, and the lowest steam temperature T2 at the discharge port was 97 ° C. Next, the pin that was supplying steam was the discharge side, and the pin that was being discharged was the supply side, while suctioning at −0.04 MPa (G) from the discharge side pin, 0.21 MPa ( G) A skin-coated foamed molded article was obtained in the same manner as in Example 2 except that the foamed particles were thermoformed by supplying steam for 10 seconds. Table 2 shows the physical properties of the obtained skin-coated foamed molded article. Since the steam discharging power is low, the supplied high-temperature steam cannot be circulated throughout the hollow molded body, and only a skin-coated molded body having low adhesion strength between the skin and the foamed particle molded body can be obtained.

Comparative Example 8
A foamed article with a skin was obtained under the same conventional production conditions as in Reference Example 1 except that the skin thickness was reduced to 1.5 mm. Table 2 shows various physical properties of the obtained foamed product with skin. Since T1 was too low and T2 was too low, only a skin-covered molded article having low adhesion strength between the skin and the foamed particle molded article was obtained.

Reference example 1
Reference Example 1 is an example of producing a skin-coated foamed particle molded body having a thick skin thickness under conventional production conditions. As usual, the epidermis thickness is 4.0 mm, the mold temperature is 60 ° C., the foaming particle content in the foaming particles is 315 g / m ³ , the conventional steam temperature is applied, and −0. A skin-coated foamed molded article was obtained in the same manner as in Example 1 except that suction was performed at 05 MPa (G). Table 2 shows the physical properties of the obtained skin-coated foamed molded article.

  The physical property evaluation methods of the skin-coated foamed molded products in Tables 1 and 2 are shown below.

[Apparent density of skin-coated foamed molded product]
The weight was determined by dividing the weight of the skin-coated foamed molded product by the volume of the molded product and converting the unit to [kg / m ³ ].

[Apparent density of molded foam particles]
The skin is cut out from the skin-covered foam molded product, the foamed particle molded product is cut out, the weight of the foamed particle molded product is divided by the volume determined from the outer dimensions of the foamed particle molded product, and the unit is [kg / m ³ ]. Obtained by conversion.

[Measurement method of material destruction rate and adhesive strength]
As test pieces for measuring the adhesive strength, 50 mm × 50 mm × product thickness was cut out from a total of five locations including the center portion and four corners (excluding the R portion) of the plate-shaped skin-coated foamed particle molded body. . The upper and lower surfaces of the test piece were firmly adhered to an adhesive strength measuring jig with an adhesive, and a skin peel test was performed on each test piece at a tensile speed of 10 mm / min with a tensile strength tester Tensilon.
Observe the fracture surface of the test piece after the above peel test, and subtract the area of the interface peeled portion from the total surface area on the adhesive surface side of the skin by the total surface area on the adhesive surface side of the skin and convert it to a percentage. The lowest value among these values was defined as the material destruction rate [%]. The maximum point stress in the test piece showing the lowest material fracture rate was defined as the adhesive strength [kgf / cm ² ].

[Measurement method of fusion rate]
As a test piece for measuring the fusion rate, 150 mm from the total 5 locations of the center and 4 corners (excluding the R portion) of the obtained plate-shaped skin-covered foamed particle molded body without including the skin. Cut out to × 150 mm × (product thickness excluding the skin). The test piece was broken to observe the fractured surface, and for 100 or more foamed particles, the number of foamed particles peeled off at the interface with the foamed particles destroyed by visual observation was measured, and the foamed foam separated from the broken foamed particles at the interface. The ratio of the expanded foam particles to the total number of particles was determined, and the lowest value among these values was defined as the fusion rate (%).

  Flexural rigidity was evaluated using a skin-coated foamed molded product having different adhesive strength between the skin and the foamed particle molded product. Table 3 shows 5 mm bending evaluation results measured by the following method as an index of bending rigidity.

[Measurement method of 5mm bending deflection load]
The length direction of the skin-covered foamed molded body (length 730 mm, width 420 mm, molded body thickness 20 mm, apparent density 200 kg / m ³ , skin average thickness 1.5 mm) obtained in Examples 2 to 6 and Comparative Example 2 A test piece having a length of 420 mm (total width of the molded body), a width of 200 mm, and a thickness of 20 mm (total thickness of the molded body) was cut out from the vicinity of the central portion so as to match the width direction of the molded body with the length direction of the test piece. Deflection of 5 mm based on JIS K7221-2: 1999, except that the test speed was 20 mm / min, the distance between fulcrums was 350 mm, the radius of the support base tip was 5 mm, and the radius of the pressure wedge tip was 25 mm. The load at the time was measured, and the measured value was defined as a bending load bent by 5 mm.

The drawing is a schematic view for explaining the arrangement of steam pins in the present invention.
Shows an example in which a steam pin is inserted from one side of the mold. Shows an example in which a steam pin is inserted from one mold surface. Shows an example in which a steam pin is inserted from one mold surface. These show the example which inserted the steam pin from the opposite side of the side surface of a metal mold | die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold 11 Mold side surface 12 Molding space part 2 Steam pin 21 Supply side steam pin 22 Discharge side steam pin

Claims (9)

  A hollow molded body is formed by hanging a parison made of polystyrene resin between molds that can be divided, clamping the mold and blow molding the parison, and then forming a polystyrene series in the hollow molded body Filled with foamed resin particles and supplied and discharged steam from a plurality of steam supply / discharge pins inserted into the hollow molded body to heat the foamed particles and fuse the foamed particles together to form a polystyrene-based resin foamed particle molded body. A method for producing a foamed molded article covered with a skin made of a hollow molded article, in which the inner surface of the hollow molded article and the foamed particle molded article are fused and integrated, and the mold temperature at the time of clamping is set to [ The glass transition temperature of the base resin of the hollow molded body is −30 ° C.] to [the glass transition temperature of the base resin of the hollow molded body + 30 ° C.], and one of the pins is the steam supply side. Is the steam discharge side, and the steam temperature T1 at the steam supply port of the pin on the steam supply side is from [glass transition temperature of base resin of foamed particles + 10 ° C.] to [glass transition temperature of base resin of foamed particles + 30 ° C.] And the steam temperature T2 at the steam discharge port of the pin on the steam discharge side is controlled to be equal to or higher than [Glass transition temperature of the base resin of the foamed particles −5 ° C.] or higher, and the surface-coated polystyrene-based resin foam molding, Body manufacturing method. 2. The method for producing a skin-coated polystyrene-based resin foam molded article according to claim 1, wherein the foaming agent content of the polystyrene-based resin expanded particles is 60 to 250 g per 1 m ^{3 of} expanded particles.   The method for producing a skin-coated polystyrene-based resin foam molded article according to claim 1 or 2, wherein the steam in the hollow molded body is sucked from a pin on the discharge side at -0.09 to -0.06 MPa (G). The bulk density of the polystyrene-based resin foamed particles is 15 to 40 kg / m ³ , The method for producing a skin-coated polystyrene-based resin foam molded article according to claim 1.   5. The method for producing a skin-coated polystyrene-based resin foam molded product according to claim 1, wherein an average thickness of the skin made of the hollow molded product is 0.5 mm or more and less than 3.5 mm. The specific surface area of the said foaming molding is 0.4-1.5cm < ² > / cm < ³ >, The manufacturing method of the skin covering polystyrene-type resin foaming molding in any one of Claims 1-5 characterized by the above-mentioned.   7. The skin-coated polystyrene according to claim 6, wherein the pin is inserted into the hollow molded body from opposite side surfaces of the periphery of the hollow molded body, and one side is a steam supply side and the other side is a steam discharge side. For producing a resin-based resin foam molded article.   In a skin-coated polystyrene-based resin foam molded body composed of a polystyrene-based resin foam molded body and a skin made of a polystyrene-based resin hollow molded body covering substantially the entire surface of the foamed particle molded body, the average thickness of the skin is 0. A skin-covered polystyrene-based resin foam molded article having a thickness of 5 mm or more and less than 3.5 mm, and a material destruction rate of the foamed particle molded article in the skin peel test of 30% or more. The skin-coated polystyrene-based resin foam molded article according to claim 8, wherein the foam molded article has a specific surface area of 0.4 to 1.5 cm ² / cm ³ .

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