JPS63242520A - Foamed plate of flexible style resin and its manufacture - Google Patents

Abstract

PURPOSE:To contrive to increase the flexibility of a foamed plate by a method in which the bubbles constituting the skin of a foamed plate is expanded in width direction of the plate, and the bubble-wall constituting the skin is protruded outward with an intermediate high portion. CONSTITUTION:The bubble 14 constituting a skin 11 is expanded with the roundness in the direction of arrow (b). The length of the bubble in the direction of arrow (b) occupies a quarter of the length in the direction of arrow (a) or more. The bubble wall of the bubble 14 is raised with an intermediate high portion, and the raised height occupies sixth of the length of the bubble in the direction of arrow (b) or more. That is, while the foamed plate such as of stylene resin is passed through between heated metallic rolls 22, and the surface of the foamed plate 21 is softened by the rolls, the foamed plate is advanced in the direction of an arrow (d) by the rotation of the rolls 22, thereby expanding the surface bubbles. Then, immediately the foamed plate is introduced to the thermal deformation temperature or lower. Here, the resin is cured under the condition where the gas is being expanded, and the obtained formed plate is taken up by take up rolls 23. Thus, the foamed plate 21 is made. The foamed plate with such construction may be easily bent, and even if the plate is bent to considerable degree, it is scarcely broken. Further, since the bubble is not broken, the water resistance and heat insulation properties of the plate are excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a flexible styrene resin foam board and a method for manufacturing the same.

(Prior Art) Styrene resin is a hard resin, and a foamed board obtained by foaming it has independent cells.

Therefore, the styrene-based resin foam board has a drawback that it has poor flexibility and is easily broken when bent. °However, when actually using styrene resin foam board,
This requires bending and fitting. Therefore, it became necessary to provide the styrene resin foam board with flexibility in order to prevent it from breaking even when bent to a certain extent.

Various methods are already known for imparting flexibility to styrene resin foam boards. For example, Special Publication No. 42-2695
Publication No. 0 teaches that a force should be applied to the foam board to mechanically shorten the length of the foam board, so to speak, to loosen the foam board in advance. Also, JP-A-58-21532
No. 9 teaches that the foam board should be bent to one side and then to the opposite side so that the longitudinal centerline of the foam board forms an arc. Additionally, it is known to press foam boards in a set of rolls to impart flexibility. All of these methods should be performed at room temperature. According to these methods, a foam board that is certainly flexible can be obtained.

(Problems to be Solved by the Invention) However, although the products obtained by these methods have improved flexibility, they have deteriorated in other physical properties.

This is because if a styrene resin foam board is deformed by applying mechanical force at room temperature, the cell walls in the foam board will be destroyed. In fact, the inventor obtained a flexible styrene resin foam board using the method described above, and when the foam board was examined, the cell walls were destroyed and the board had considerable air permeability. . This means that water resistance and heat insulation properties are also reduced. Therefore, it became necessary to impart flexibility to the styrene resin foam board without destroying the air bubbles.

The object of the present invention is to provide flexibility to a foamed styrene resin board without destroying the cell walls of the foamed board, and therefore without impairing waterproofness or heat insulation properties. Furthermore, the purpose is to efficiently impart flexibility to the foam board through extremely easy processing.

(Means for solving the interlayer problem) Almost all styrene resin foam boards are made by extrusion foaming. Therefore, the inventor closely observed the structure of a styrene resin foam board made by extrusion foaming. As a result, the inventor found that a fairly flat skin 1 was formed on the surface of the styrene resin foam board made by extrusion foaming, as shown in FIG. It was confirmed that all of the bubbles 4 in the sample were elongated in the direction of the epidermis, and that most of the bubbles located near the epidermis were oriented in the direction of the epidermis. As a result, the inventor thought that the reason why the foam board has poor flexibility is that the skin extends in a flat manner, without any curved bends, and therefore there is not enough room for the skin to extend. .

Therefore, the inventor proposed that by expanding the cells constituting the skin of a foam board in the thickness direction of the board and raising the cell walls constituting the skin to a medium-high height toward the outside, foaming I thought this would increase the flexibility of the board.

Based on this idea, we devised a method in which the cell walls that make up the skin of the foam board are raised toward the outside to a medium-high height. As a result, the surface of the foam board is heated from the surface for a short period of time to raise only the surface of the foam board to a temperature slightly higher than the softening temperature of the resin, causing the air bubbles on the surface to expand, and then the surface of the foam board is not suddenly lowered to a low temperature. In this way, the walls of the bubbles are hardened while the gas inside the bubbles is allowed to expand. As a result, the surface cells were raised to a medium height, and it was confirmed that a flexible foam board could be obtained without destroying the cell walls. This invention was completed based on such confirmation.

One of the inventions related to this application is an invention related to a flexible styrene resin foam board. The invention provides a foam board having substantially uniform closed cells, with most of the cells along at least one surface being closed, forming a continuous skin on the surface. The bubbles are rounded and expanded both in the direction of the epidermis and in the direction perpendicular thereto, and the length of the bubbles in the vertical direction occupies more than a quarter of the length in the direction of the epidermis. , a flexible styrene-based resin foam board, characterized in that the cell wall constituting the skin is raised to a medium height for each cell, and the raised height reaches one-sixth or more of the height in the vertical direction. be.

Further, in connection with the invention of the above product, this application also includes an invention of a method for manufacturing the above product.

The invention of the manufacturing method is such that, in a state where the surface of a styrenic resin foam board having substantially uniform closed cells is below the heat distortion temperature of the resin, at least one surface of the foam board is coated with heat distortion temperature. A metal roll heated to a temperature of 5 to 150 degrees Celsius is brought into contact with the foam board, and the surface of the foam board is heated and softened by heat conduction from the roll surface.
Flexible styrene resin foam, characterized by advancing the foam board by rotating a roll to expand the surface bubbles, and then exposing the foam board to a temperature below the heat deformation temperature of the resin to harden the resin. This invention relates to a method for manufacturing a board.

C) Examples of invention of product) Of the above two inventions, the invention of product will be explained first based on the drawings. FIG. 1 is a partially cutaway enlarged perspective view of a resin foam board according to the present invention. FIG. 2 is an enlarged partially cutaway perspective view of a conventional resin foam board.

Styrene resin foam board generally has a thickness of 10-150fi.
, an average density of 20-50 kg/door size, and a uniform and finely foamed product is required. This type of foam board is made by press-fitting aliphatic hydrocarbons such as propane and butane, and tetragenated aliphatic hydrocarbons such as methyl chloride and dichlorodifluoride methane into a styrene resin, which is then heated and softened. In this state, the resin is transferred to a low pressure region, and the hydrocarbons are vaporized within the resin, and the hydrocarbons generate bubbles in the resin to form a foam. Therefore, each bubble becomes independent. In practice, foam boards were often made by extrusion foaming.

A conventional styrene-based resin foam board, for example, a styrene-based resin foam board that has been extruded and foamed, has a structure as shown in FIG. 2 when a portion close to the skin is cut and enlarged. In FIG. 2, l is the skin of the foam board, arrow a indicates the extrusion direction, cross section 2 is parallel to the extrusion direction a and perpendicular to the skin 1, and cross section 8 is the cross section between the extrusion direction a and the skin 1. This is a cross section perpendicular to .

In FIG. 2, the skin 1 extends in a continuous, substantially flat surface. Although there may be small openings p here and there in the epidermis 1, overall the epidermis 1
forms a continuous plane, so most of the bubbles lining the surface are closed. Moreover, the bubbles inside the bubbles have an independent structure, have a substantially uniform size throughout, and are evenly distributed.

In FIG. 2, the shape of the bubbles differs greatly depending on whether the bubbles are located close to the skin 1 or inside the foam board. That is, the bubbles 4 in contact with the epidermis on the cross section 2 are largely elongated in the direction in which the epidermis 1 extends, and have a flat shape. However, the bubble 5 located inside on the cross section 2 has a shape that is almost spherical as a whole, although it is somewhat angular. The same is true on the cross section 8, and the bubbles 6 close to the epidermis 1 are
Although the bubbles 7 are elongated and flattened in the direction in which they extend, the bubbles 7 located inside have a shape close to a sphere as a whole.

The flatness of the bubble 4 is determined by the length X along the direction perpendicular to the epidermis 1 on the cross section 2 being 4 of the length y in the direction parallel to the epidermis 1.
It is less than one-fifth, usually less than one-fifth. Further, the skin 1 constituting the bubbles 4 is almost flat and does not have a middle or high height. The height of the protrusion is at most one-tenth of the size of the bubble. That is,
The elevation height is expressed as the length of the perpendicular line drawn from the highest protruding point of the epidermis to the straight line connecting the points where the bubble contacts adjacent bubbles on the epidermis that appears in Section 2. , the length of this leg is less than one tenth of the length of X.

In contrast, the bubbles located inside the plate are approximately spherical as described above. That is, the length of one bubble along the direction on the cross section 2 is approximately equal to the length along the direction a, and even if the length varies greatly, one bubble accounts for more than the other.

On the other hand, the styrenic resin foam board according to the present invention,
The structure is as shown in Figure 1.

The foam board shown in FIG. 1 has substantially uniform closed cells, with most of the cells lining the surface being closed.
It is the same as the styrene resin foam board shown in FIG. 2 in that a continuous skin is formed on the surface.

The foam board shown in FIG. 1 differs from the foam board shown in FIG. 2 in the structure of the cells near the skin. That is, the one in FIG. 1 differs from the one in FIG. 2 in that the bubbles constituting the skin are expanded in a rounded manner in a direction perpendicular to the skin direction. Furthermore, with reference to FIG.
4 is expanded roundly in the direction indicated by the arrow, and the length of the bubble 14 in the direction b occupies more than a quarter of the length in the direction a, and the bubble wall of the bubble 14 is The relationship is such that the bubble is raised to a medium height, and the raised height occupies more than one-sixth of the length of the bubble in the direction of the arrow.

Here, the elevation height means, as mentioned in the second @, a perpendicular line drawn from the highest protruding point of the epidermis to a straight line connecting the point where the bubble 14 contacts the barrier bubble on the epidermis 11 that appears in the cross section 12. In this case, the leg length 2 of the perpendicular line is equal to or more than 1/6 of the length X of the bubble 14 in the b direction.

In the foam board according to the present invention, not only the cell walls constituting the skin 11 are expanded to have a rounded shape, but also
As shown in FIG. i, the adjacent bubble inside the bubble is also expanded in the b direction. In a conventional foam board, as shown in Figure 2, all the air bubbles located in several layers (usually 2 to 8 layers) from the skin 1 to the inside are stretched in the direction a, and therefore the air bubbles are The size X in the b direction was set to be one-fourth or less of the size y in the a direction. However, in the foam board according to the present invention, all the bubbles located in several layers from the skin 11 toward the inside are expanded also in the b direction, and the length of the bubbles in the b direction is equal to the length in the a direction. This accounts for more than a quarter of the total.

Styrenic resins include not only styrene homopolymers but also copolymers of styrene and other monomers. Examples of other monomers include methyl methacrylate and acrylonitrile.

In addition, styrene resins also include blends of styrene homopolymers or copolymers mixed with other resins.

(Effects of the Invention of the Product) Since the foam board according to the present invention has a structure as shown in FIG. 1, when the foam board is bent, it can be easily bent and The foam board rarely breaks even when bent. For this reason, the foam board according to the present invention can be easily bent and fitted during installation. Furthermore, this foam board has good water resistance and heat insulation properties because the cells are not destroyed. In addition, this foam board has small irregularities on its surface, so the sliding friction on the surface is large, so when used on tatami floors, etc., there is less slippage, and the adhesive strength to other objects is improved. This is advantageous when used in a laminated or bonded manner.

(Embodiment of the Invention of the Method) The method of the invention is carried out as shown in FIG. A styrene-based resin foam board 21 is passed between a pair of heated metal rolls 22, the surface of the foam layer 21 is softened by the rolls 22, and the foam board is advanced in the direction of arrow d by the rotation of the rolls 22, causing surface bubbles to form. This is a method in which the foamed board is immediately brought to a temperature below the heat distortion temperature, the resin is cured while the gas is expanded to form a foamed board, and this is taken up by a take-up roll 28 to form a foamed board. .

In the method of this invention, a styrene resin foam board having substantially uniform closed cells is used as a raw material. This foam board has a skin structure as shown in FIG. This foam board requires that only its surface be cooled to at least a heat distortion temperature or lower. Therefore, even if the foam board has just been extruded, the method of the present invention can be applied to the foam board as long as the surface has reached a temperature below the heat deformation temperature. Contact with heated metal rolls. This roll has a temperature that is higher than the heat deformation temperature of styrene resin in accordance with the advancing speed of the foam board.
℃ to 150°C higher. The reason why this temperature is required is that the surface of the resin foam board cannot be softened unless it is at least 5°C higher than the heat deformation temperature of the resin, and it is also 150°C or more higher than the heat deformation temperature of the resin. In this case, even if the foam plate advances at a faster speed, it will melt and break the cell walls.
This is to maintain an appropriate temperature between them.

The roll is preferably coated with a fluororesin to prevent heated styrenic resin from sticking to its surface. Further, although the roll surface may be made smooth, it is preferable to knurl the surface to provide small irregularities.

The contact by the rolls causes the rolls to press against the styrenic resin foam board, causing the foam board to reduce its thickness and become compressed at the contact location. The degree of thickness compression is 2% or more of the thickness50
% or less. Further, the foam board is advanced by the roll at a speed of 0.3 to 80 m/min depending on the roll temperature.

In other words, the higher the roll temperature, the faster the foam board advancing speed should be. While compressing the foam board as described above,
When the foam board is advanced at such a speed, only the outer skin portion of the foam board is appropriately softened, and the inside portion remains unsoftened.

The foamed board thus obtained maintains its closed-cell properties and is highly flexible. Therefore, even if the foam board is bent, the foam board does not easily break, and therefore, bending is easy. Therefore, this foam board is convenient to use as described above.

(Effects of the Invention of the Method) According to the method of the invention, at least one portion of the foam board is heated at a temperature below the thermal deformation temperature of the resin. A metal roll heated to a specific temperature is brought into contact with the surface of the foam board, and the surface of the foam board is heated and softened by heat conduction from the roll surface, and the foam board is advanced by the rotation of the roll, causing the surface bubbles to expand. Next, it is sufficient to expose the foam board to a temperature below the heat distortion temperature of the resin to harden the resin, so it is easy to operate and can be carried out continuously, so it can be connected to the process of making the foam board using an extruder. Therefore, it is possible to efficiently obtain a flexible foam board. Moreover, since the above-mentioned specific temperature is within a wide range of 5° C. to 150° C. higher than the thermal deformation temperature of the resin in the case of heating, implementation is easier. Therefore, the method of this invention brings about significant practical effects.

Next, an example of a specific implementation of the manufacturing method will be described.

Hereinafter, parts simply mean parts by weight.

Example 1 A styrene homopolymer was used as the styrene resin, and 100 parts of the polymer was mixed with 0.5 parts of finely powdered talc as a bubble control agent, 2 parts of hexabromocyclododecane as a flame retardant, and a small amount of coloring agent. were added and kneaded to obtain a resin composition.

This resin composition was supplied to an extruder. As an extruder,
Those with diameters of 50 m and 65 m were used by connecting them in series in this order. The resin composition was supplied to this extruder at a rate of 60 Kf/hour, and a foaming agent was press-fitted near the tip of the extruder having a diameter of 50 fl. As a blowing agent, a mixture of 3 parts of dichlorodifluoromethane and 7 parts of methyl chloride was used,
This mixture was press-fitted at a ratio of 9 parts to 100 parts of resin.

As a mouthpiece, place a 1ws thick 100mm width on the resin discharge surface,
A rectangular resin outlet with a length of 51 m was used. The molding tool was placed in close contact with the tip of the cap. The molding tool has a resin passage formed therein, and the resin passage has an inlet side that is equal to the resin outlet of the mouthpiece, and an exit side that is 25 m thick and 200 mm wide. length 100
The shape of the building is designed so that the entrance is clear and the wall gradually expands towards the exit. The walls of the resin passage were coated with fluororesin.

The resin supplied to the extruder with a diameter of 50 m was heated to 220° C., kneaded in a molten state, and then lowered to 120° C. in the extruder with a diameter of 60 m and supplied to the die. The resin extruded from the nozzle is foamed to a high magnification, and is arranged to have a thickness of 28fflI, a width of 230m, and a density of 28.0.
The result was a -secondary foamed board with Kf/-. This - next foam board is 4
It was picked up at a speed of 7 minutes.

The primary foam board thus obtained had a skin portion having a structure as shown in FIG. 2. That is, the skin was extended in a substantially planar shape, and the bubbles in the vicinity of the skin were stretched in the extrusion direction and became flat.

This second foam board is produced by further progressing and when the surface has cooled down to below the heat distortion temperature of the resin, a pair of heated metal rolls are brought into contact with the surface of the foam board, and between the rolls. was pressed by. At the position of the roll, the surface temperature of the foam board was 82°C, and the center temperature was 68°C.

The rolls have a diameter of 120B, are heated to 160°C, and are placed at 22-tone intervals to roll the foam board by 4m.
The process progressed at a speed of /min.

The secondary foam board has a thickness of 275 mm and a density of 28.5 Kf/-
The surface part had a structure as shown in Figure 1. In other words, the air bubbles that make up the skin are expanded in a rounded manner in the thickness direction of the board, and the length of the air bubbles in the thickness direction accounts for more than a quarter of the length in the extrusion direction, forming the skin. All of the cell walls were raised to a medium height, and the raised height was one-sixth or more of the length in the thickness direction of the board. Furthermore, in a portion approximately 2 cm thick from the epidermis, all the bubbles were round and the average diameter of the bubbles was 0.38 m. Further, in the inner part with a thickness of about 4 fl, the bubbles were stretched in the extrusion direction and appeared to be compressed in the thickness direction. Further, when an electron micrograph of the bubbles in this area was taken, it was found that there were many wrinkles.

Regarding the secondary foam board, the amount of bending deflection at breakage was measured according to JISA 9511 under the conditions of a measurement span of 150 feet and a loading rate of 10 feet/min. recognized as rich.

Example 2 This example is the same as Example 1 except that when the temperature of the secondary foam board reached 85°C on the surface and 100°C inside, it was pressed with a pair of rolls. A secondary foam board was obtained by processing in exactly the same manner.

This secondary foam board has a thickness of 28.1 m, a density of 27,
At s Ky/rr/, all the bubbles were foaming in a rounded manner in the thickness direction of the board from the epidermis to the inside.

That is, inside the secondary foamed board obtained in this example, unlike the secondary foamed board obtained in Example 1, wrinkled air bubbles that appear to have been compressed in the thickness direction were not observed. First, the entire cell foamed uniformly, and the average cell diameter in a 2.5 fl thick portion from the epidermis was 0.41 mm. Regarding this secondary foam board, when the amount of bending deflection at breakage was measured in the same manner as in Example 1, the amount of deflection was 112 m, and it was recognized that it had flexibility.

Since this secondary foam board did not have wrinkled cells under the skin, it was inferior to that of Example 1, but was superior to that obtained in the comparative example described later.

Example 8 This example was treated in the same manner as in Example 1, except that -
Next, the rolls were brought into contact when the foamed board was sufficiently cooled to the inside, and the distance between the rolls was shortened to 18 rolls.

In this way, the thickness is 26.5IfII and the density is 29.3 Kg.
/ Obtained secondary foam board for door. In this secondary foam board, the number of air bubbles within a thickness of 15 m from the skin to the inside is approximately 0.42
It had an average diameter of m+ and was expanded with a roundness in the thickness direction of the board. In addition, the bubbles in the <7ttri thickness area following the 2.5fl thickness area were wrinkled and had an elongated shape in the extrusion direction.

When the amount of deflection of this secondary foam board was measured in the same manner as in Example 1, the amount of deflection was 20.1 fl, which was found to be highly flexible.

Example 4 In this example, Example 1 was implemented with some changes. The changes were made by shortening the distance between the rolls to 18 degrees, lowering the roll temperature to 120°C, using a second foam board that is cooled to the inside, and slowing down the advancing speed of the foam board. This is the point where the speed was set at 0.5 m/min.

The obtained secondary foam board has a thickness of 26°2 and a density of 29.6.
Kg/m and 2.0 kg/m from the epidermis. ．． The bubbles in the 8 m thick part had a structure as shown in FIG. 1, and expanded roundly in the thickness direction of the plate, and the average bubble diameter was 0.37 sn+.

In addition, the air bubbles in the area <7.5 fl following the 2.8 rin thick area from the epidermis have wrinkles and are stretched in the extrusion direction, and the air bubbles in the central part of the plate inside are wrinkled. teeth,
It was spherical in shape.

When the amount of deflection of this secondary foam board was measured in the same manner as in Example 1, the amount of deflection was 19.5B, which was found to be highly flexible.

Example 5 In this example, Example 1 was implemented with some changes. The change was to raise the roll temperature to 210℃,
- The only difference is that a foam board that was cooled to the inside was used as the secondary foam board, and the rotation speed of the roll was increased to advance the foam board at a speed of 10 m/min.

The obtained secondary foam board had a thickness of 27.3B, a density of 28,
OKflrd, and the bubbles within the 15 fl thick part from the epidermis have a structure as shown in Figure 1.
The cells expanded roundly in the thickness direction of the plate, and the average bubble diameter was 0.38B. Also from the epidermis 15
In the 5III+ thickness section following the mts thickness section, the air bubbles had wrinkles and were compressed in the thickness direction◎ When the amount of deflection of this secondary foam board was measured in the same manner as in Example 1, the amount of deflection was 15. At .6 m, the foam board was found to be highly flexible.

Comparative Example Regarding the primary foam board obtained in Example 1, the amount of bending deflection at break was measured by the method described in Example 1.
The amount of deflection was 6.8, and it was recognized that the flexibility was poor.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway enlarged perspective view of a resin foam board according to the present invention. FIG. 2 is an enlarged partially cutaway perspective view of a conventional resin foam board. FIG. 3 is a cross-sectional view schematically showing the method of this invention. Patent applicant: Sekisui Plastics Co., Ltd. Figure A Figure 2 Figure 5 Procedural amendment June 22, 1988 2. Name of the invention Flexible styrenic resin foam board and method for manufacturing the same 3. Amended. Relationship with author case Patent applicant 4, agent & Detailed explanation of the invention in the statement of subject matter of amendment & Contents of amendment (+) On page 21, line 11 of the specification, it says “160°C” , corrected as "140℃". (2) On page 26, line 5, ``210℃'' should be corrected to ``160℃.'' (3) The following shall be inserted between lines 1 and 2 on page 27. In the example, Example 1 was modified with some changes.The changes were that the obtained primary foam board was left for 8 days after acquisition, and then rolled to form a secondary foam board. The obtained secondary foam board had a thickness of 28.0 fl and a density of 27.0 fl.
8 KI/m, and all the bubbles were round in the area about 2.5 fl from the epidermis, and the average diameter of the bubbles was 0.8 KI/m.
It was 40m+. Further, in a part approximately 5 meters thick following a part approximately 15 m thick from the epidermis, air bubbles had wrinkles and were compressed in the thickness direction. When the amount of deflection of this foam board was measured in the same manner as in Example 1, the amount of deflection was 18.5 m, and the foam board was recognized to be highly flexible. Example 7 This example was carried out in much the same way as Example 6, except that the spacing between the rolls was changed to 27 baits. The obtained secondary foam board had a thickness of 28.2 m. The density was 27.8 Ky/lri, and all the bubbles were foaming in a rounded manner in the thickness direction from the epidermis to the inside. That is, no wrinkled air bubbles were observed inside this foam board, and the average cell diameter of the skin was 0.42 m. The amount of bending deflection of this foam board at breakage is 12. ．． 0 tone, and was recognized as having flexibility. This secondary foam board did not have wrinkled air bubbles under the skin, so it was inferior to Example 1, but superior to the comparative example described later. j or more

Claims (1)

[Claims] 1. A foam board having substantially uniform closed cells, in which most of the cells lined up along at least one surface are closed, and a continuous skin is formed on the surface, The bubbles that make up the epidermis are rounded and expanded both in the direction of the epidermis and in the direction perpendicular to it, and the length of the bubbles in the vertical direction is more than a quarter of the length in the direction of the epidermis. flexible styrenic resin, characterized in that the cell wall constituting the epidermis is raised to a medium height for each cell, and the raised height reaches one-sixth or more of the length in the vertical direction. Foam board. 2. In a state where the surface of the styrene resin foam board having substantially uniform closed cells is below the heat distortion temperature of the resin, at least one surface of the foam board is heated by 5°C or more above the heat distortion temperature. A metal roll heated to a temperature higher than 150°C is brought into contact with the foam board, and the foam board surface is heated and softened by heat conduction from the roll surface, and the foam board is advanced by the rotation of the roll, causing the surface bubbles to expand. A method for producing a flexible styrenic resin foam board, the method comprising: then exposing the foam board to a temperature below the thermal deformation temperature of the resin to cure the resin.