JP2009143148A - Thermoplastic resin foamed board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin foamed board which is light in weight and excellent in compression modulus and bending stiffness in a particular direction. <P>SOLUTION: In the thermoplastic resin foamed board having a core and surfaces 2 on upper and lower sides of the core, the core is formed by stacking a plurality of thermoplastic resin foamed sheets 1 on one another, and the surfaces of the thermoplastic resin foamed sheets are orientated in the thickness direction of the thermoplastic resin foamed board. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thermoplastic resin foam board and a method for producing the same. More specifically, a thermoplastic resin foam board that is lightweight and has excellent compression rigidity and bending rigidity in a specific direction by secondary processing of the thermoplastic resin foam sheet, and various thicknesses by simply adjusting the thermoplastic resin foam board. It is related with the method which can be manufactured.

  Foamed boards made of thermoplastic resins are light and resource-saving, have excellent heat insulation and buffering properties, and are recyclable. Therefore, they are used in various applications such as heat insulating materials and packaging materials.

  However, foam boards tend to have lower compression and flexural rigidity at lower density, and surface pressure such as floor base materials laid under flooring materials and core materials for sandwich panels and fiber reinforced composites in buildings. On the other hand, in applications where high rigidity is required, it is difficult to achieve both weight reduction.

  As a method for improving the compression rigidity of the foam board, Patent Documents 1 and 2 propose that the size of the cell structure is larger in the thickness direction than in the other direction. However, it is difficult to sufficiently improve the compression rigidity only by adjusting the cell structure, and when the thickness is changed, the size and anisotropy of the cell change, so that the physical properties change depending on the thickness. Further, the method of Patent Document 2 has a drawback in that the control is complicated because it is necessary to open between molds at a strict speed.

On the other hand, Patent Document 3 proposes a laminated sheet in which a soft synthetic resin foam sheet is folded in a bellows shape and a flexible synthetic resin sheet is laminated on either the front or back side. However, Patent Document 3 relates to a protective material that can be wrapped by following the corners of an object to be packaged, and does not disclose any high-rigidity thermoplastic resin foam board.
JP 60-198230 A Japanese Patent No. 30675548 Japanese Utility Model Publication No. 4-71233

  An object of the present invention is to provide a thermoplastic resin foam board that is lightweight, excellent in compression rigidity, and excellent in bending rigidity in a specific direction, and a simple method for producing the thermoplastic resin foam board.

  As a result of intensive studies to solve the above-mentioned problems, the inventors have made a thermoplastic resin foam board comprising a core portion formed by vertically arranging thermoplastic resin foam sheets and a skin portion capable of integrating the core portion. However, it has been found that it has excellent compression rigidity and bending rigidity in a specific direction.

  That is, according to a first aspect of the present invention, in the thermoplastic resin foam board having a core portion and skin portions above and below the core portion, the core portion is formed by laminating a plurality of thermoplastic resin foam sheets, and the heat The present invention relates to a thermoplastic resin foam board, wherein the surface of the thermoplastic resin foam sheet is oriented in the thickness direction of the thermoplastic resin foam board.

  2nd of this invention is related with the manufacturing method of the said thermoplastic resin foam board.

  As a preferred embodiment, the thermoplastic resin foam sheet is folded at regular intervals to laminate the thermoplastic resin foam sheet into a core part, and is formed on a surface constituted by a ridge formed by folding the thermoplastic resin foam sheet. The method for producing a thermoplastic resin foam board according to the above description, characterized in that the skin portion is formed by adhering a face material. As another preferred embodiment, the thermoplastic resin foam sheet is folded at regular intervals to provide thermoplasticity. By laminating resin foam sheets to form the core, the surface composed of the ridges formed by folding the thermoplastic resin foam sheet is heated, and the ridges of adjacent thermoplastic resin foam sheets are fused together The present invention relates to a method for producing a thermoplastic resin foam board as described above, wherein the outer skin portion is formed.

  Since the thermoplastic resin foam board of the present invention is oriented in the thickness direction of the thermoplastic resin foam board from which the surface of the thermoplastic resin foam sheet can be obtained, it is lightweight yet highly rigid. The bending rigidity in the direction orthogonal to the orientation direction of the thermoplastic resin foam sheet constituting the core is high. Therefore, it is useful as a core material for sandwich panels.

  Moreover, according to the manufacturing method of this invention, the thermoplastic resin foam board excellent in rigidity can be obtained easily by adding simple secondary processing to a thermoplastic resin foam sheet.

  The thermoplastic resin foam board of the present invention is a thermoplastic resin foam board having a core part and skin parts above and below the core part, wherein the core part is formed by laminating a plurality of thermoplastic resin foam sheets, and The surface of the thermoplastic resin foam sheet is oriented in the thickness direction of the thermoplastic resin foam board.

  A well-known thing can be used for the thermoplastic resin foam sheet used for the thermoplastic resin foam board of this invention. Also, for example, a method in which a thermoplastic resin and a volatile foaming agent are kneaded in an extruder, cooled to a foamable temperature, and extruded from a T die or a circular die under a low pressure, and a thermoplastic resin and a decomposable foaming agent are extruded. A method of kneading in a machine, thermally decomposing the decomposable foaming agent, cooling to a foamable temperature, and extruding from a T die or a circular die under a low pressure, a thermoplastic resin and a decomposable foaming agent are substantially Examples thereof include those obtained by kneading in an extruder at a temperature that does not decompose automatically, extruding from a T-die into a sheet shape, crosslinking with an electron beam, etc., and then forming a foamed sheet by a known method such as heat foaming.

  Examples of the thermoplastic resin include polyolefin resins, aromatic alkenyl resins, polyester resins, vinyl chloride resins, (meth) acrylic ester resins, polyphenylene ether resins, polycarbonate resins, polyamide resins, polyimide resins. Resin etc. are mentioned. Of these, polyolefin resins are preferable because of excellent oil resistance, and polypropylene resins are preferable because of excellent heat resistance.

The density of the thermoplastic resin foam sheet is preferably ³⁰ to 300 kg / m ³ because the foamed board obtained is lightweight and has high rigidity.

  In addition, as the thickness of the thermoplastic resin foam sheet, it is easy to obtain a foam sheet by the above-mentioned known method, and in the case of producing a thermoplastic resin foam board by folding, which will be described later, Since bending (buckling) hardly occurs, the thickness is preferably 0.8 to 5 mm.

  Further, for the purpose of further increasing the rigidity of the obtained thermoplastic resin foam board, a thermoplastic resin foam in which a non-foamed layer made of a thermoplastic resin extruded from a film or a T-die is laminated on at least one surface of the thermoplastic resin foam sheet. A sheet may be used. The resin forming the non-foamed layer is preferably the same kind of thermoplastic resin as that of the foamed sheet from the viewpoint of adhesion to the thermoplastic resin foamed sheet and recyclability.

  The thickness of the non-foamed layer laminated on the foamed layer is not particularly limited, but it is 0.5 mm or less because it is easy to fold in the case of producing a thermoplastic resin foam board by folding as will be described later. It is preferable.

  As a method for producing the thermoplastic resin foam board of the present invention, the core of the thermoplastic resin foam board is formed by laminating a plurality of thermoplastic resin foam sheets, and the surface of the thermoplastic resin foam sheet is a thermoplastic resin. There is no particular limitation as long as it can be oriented in the thickness direction of the foam board, and as a method of forming a core portion by stacking thermoplastic resin foam sheets, for example, (1) a strip of thermoplastic resin foam sheets at regular intervals And (2) lamination by folding a thermoplastic resin foam sheet at regular intervals.

  Among them, (2) a method of forming a core by laminating a thermoplastic resin foam sheet at a regular interval corresponding to the thickness of a desired thermoplastic resin foam board is preferable because it is simple in work. is there.

  In the present invention, that the thermoplastic resin foam sheets are laminated means that the surfaces of the thermoplastic resin foam sheets are in contact with each other.

  As a method for folding the thermoplastic resin foam sheet, a known method can be used. For example, the thermoplastic resin foam sheet is passed through a roll having a gear-shaped cross section, and creases are gradually formed by a number of rolls. .

  For the purpose of folding at the desired position in the step of folding the thermoplastic resin foam sheet, it is preferable that a groove such as a cut not to cut the foam sheet is provided in advance. The depth of the concave line is not cut in the case of the bottom of the concave line and the cut line because the foamed thermoplastic resin sheet is not cut in the subsequent folding process and can be sufficiently creased. The thickness of the remaining part is preferably 0.05 to 0.5 mm. However, even if there is a part of the cut portion that penetrates like a perforation, the thermoplastic resin foam sheet may not be completely cut in the folding process.

  By applying the concave stripes to the front and back surfaces of the thermoplastic resin foam sheet alternately at regular intervals, the accuracy of the folding interval is improved, and the thickness accuracy and surface smoothness of the finally obtained thermoplastic resin foam board are improved. improves.

  And as a method of giving the concave strip to the thermoplastic resin foam sheet, for example, it is passed through a roll with a blade, cut with a large number of fixed blades arranged in the width direction while being taken, cut with a cutter traveling in the width direction, blade For example, it may be sandwiched by a press with a mark.

  As a method of forming the core portion by folding the thermoplastic resin foam sheet, for example, the bellows is formed from the opening portion into a space in which only one surface corresponding to the side surface of the thermoplastic resin foam board is opened and the other five surfaces are closed. Adjust the feed amount of each folded surface of the thermoplastic foam sheet with a method of feeding the molded thermoplastic resin foam sheet, or a jig that can be fitted or clamped to the end of the thermoplastic resin foam sheet And the like.

  In the present invention, the interval at which the thermoplastic resin foam sheet is cut or folded into strips is determined by the thickness and configuration of the target thermoplastic resin foam board. For example, when bonding face materials to the top and bottom of the core, it is preferable that the thickness be close to the thickness of the target foam board. When the top and bottom of the core are heated and fused, the target thermoplastic resin foam board It is preferable that the interval is wider than the thickness.

  In the present invention, unless otherwise specified, the cut surface when the thermoplastic resin foam sheet is cut into strips is referred to as a “cut end”, and when the thermoplastic resin foam sheet is folded, the crease portion is Although referred to as “ridge part”, the method of forming the skin part on the upper and lower sides of the core part is as follows: A method of bonding the material, (4) a cutting end portion of the core portion, or a surface constituted by the ridge portion, that is, the upper and lower sides of the core portion is heated, or the cutting end portion of the adjacent thermoplastic resin foam sheet, or For example, a method of fusing ridges to each other can be used.

  Although there is no restriction | limiting in particular as a face material used for the said adhesion | attachment, Since it becomes easy to recycle, it is preferable that it is the same resin as a thermoplastic resin foam sheet, or a similar resin.

  In addition, other materials such as a metal thin plate may be used as the face material for the purpose of significant improvement in rigidity, heat resistance, and the like.

  Examples of the method for adhering the face material on the upper and lower sides of the core include use of an adhesive and heat bonding by heating from the face material or preheating before the face material is laminated. Among these, since reliable adhesive strength can be obtained by a simple process, adhesion using a hot melt adhesive is preferable. When bonding with a hot melt adhesive, it is preferable to perform the bonding at a temperature at which only the adhesive does not melt and the face material and the thermoplastic resin foam sheet do not melt. Here, the temperature at which the face material and the thermoplastic resin foam sheet do not melt means that the temperature is lower than the melting point if it is a crystalline resin, and is lower than the glass transition temperature if it is an amorphous resin.

  When the surface composed of the cut end portion or ridge portion of the core portion is heated and the cut end portions or ridge portions of adjacent thermoplastic resin foam sheets are fused, the cut end portions or ridge portions are melted and compressed. By integrating the cut ends or ridges of the adjacent thermoplastic resin foam sheets, the thickness of the thermoplastic resin foam board obtained as described above is cut into a strip shape or folded thermoplastic It becomes thinner than the interval between the resin foam sheets.

  When forming the skin part in the core part, when compressing in the thickness direction of the thermoplastic resin foam board, it is possible to suppress the decrease in rigidity due to buckling of the thermoplastic resin foam sheet by sufficiently performing preheating. ,preferable. As the preheating temperature, since the thermoplastic resin is sufficiently melted and excessive deterioration of the thermoplastic resin can be suppressed, the crystalline resin has a melting point +10 to the melting point + 50 ° C., and the amorphous resin has a glass transition. It is preferable that it is temperature + 10-glass transition temperature +80 degreeC. Moreover, as a ratio to compress, since lightness is maintained and a cutting | disconnection edge part or a ridge part fully fuse | melts and integrates, it is 0.5-0.9 times the thickness before a heating. preferable.

  In a preferred embodiment of the production method of the present invention, a thermoplastic resin foam sheet is folded at regular intervals to form a core part by laminating the thermoplastic resin foam sheet, and a ridge formed by folding the thermoplastic resin foam sheet. A face material is adhered to a surface constituted by forming a skin portion.

  In another preferred embodiment, the thermoplastic resin foam sheet is folded at regular intervals to form a core part by laminating the thermoplastic resin foam sheet, and the ridge part is formed by folding the thermoplastic resin foam sheet. The surface is heated and the ridges of adjacent thermoplastic resin foam sheets are fused together to form a skin part.

  By producing the thermoplastic resin foam board of the present invention in these embodiments, a desired thickness excellent in compression rigidity and bending rigidity in a specific direction is obtained by simple secondary processing to the thermoplastic resin foam sheet. This is preferable because the thermoplastic resin foam board can be efficiently produced.

  The thermoplastic resin foam board of the present invention obtained as described above exhibits excellent rigidity despite being lightweight, and further, the orientation of the thermoplastic resin foam sheet of the thermoplastic resin foam board. When the thermoplastic resin foam sheet is folded, the bending rigidity in the direction orthogonal to the ridge portion is high.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples.

<Evaluation of compression modulus of thermoplastic resin foam board>
After leaving a test piece having a cross section of 50 mm × 50 mm and a thickness of about 10 mm for one day in a thermostatic chamber at 23 ° C., a compression test is performed using an autograph manufactured by Minebea Co., Ltd., TG-20kN, and an initial compression modulus is obtained. Was measured. The test was performed until the maximum stress of the load cell was 20 kN, the test speed was 25 mm / min, and the stress was 20 kN. The initial elastic modulus was obtained from the initial stress rising portion of the strain-stress curve using data processing software SR-01 manufactured by Minebea Co., Ltd.

<Measurement of melting point or glass transition temperature of thermoplastic resin foam sheet>
In the measurement by the differential scanning calorimetry method, 4 to 10 mg of the foamed sheet is cut out and used as a sample. In an endothermic curve obtained when the temperature is increased from 40 ° C. to 210 ° C. at a rate of 10 ° C./min and melted, polypropylene resin and the like In the case of the crystalline resin, the peak at which the endothermic amount becomes the maximum was taken as the resin melting point, and in the case of the amorphous resin such as polystyrene resin, the midpoint of the temperature range where the slope of the endothermic curve changed was taken as the glass transition temperature.

Example 1
After 100 parts by weight of a propylene homopolymer (melt flow rate 3 g / 10 min at 230 ° C.) and 0.25 parts by weight of t-butyl peroxybenzoate were stirred and mixed with a blender, the mixture was supplied to a 44 mmφ twin screw extruder and liquid-added. Using a pump, 0.5 part by weight of isoprene was press-fitted from the middle of the extruder, and melt-kneaded at 200 ° C. to obtain a modified polypropylene resin.

Supplying a blend of 100 parts by weight of the modified polypropylene resin and 0.14 parts by weight of a baking soda-based foaming agent as a cell nucleating agent with a ribbon blender to a tandem extruder composed of 115 mmφ single shaft-150 mmφ single shaft And melted in a first stage extruder (115 mmφ) set at 200 ° C., and then 1.7 parts by weight of isobutane as a foaming agent was injected into 100 parts by weight of the resin composition and set at 162 ° C. Cooled in a second stage extruder (150 mmφ), discharged from a circular die (225 mm) under atmospheric pressure, blown while being molded in a 670 mmφ cooling cylinder, and blown inside to stretch and cool, An extruded foam sheet having a width of 1050 mm was obtained by cutting into two sheets with a cutter. The density of the obtained extruded foamed sheet was 145 kg / m ³ , the closed cell ratio was 78%, the thickness was 1.9 mm, the basis weight was 0.28 kg / m ² , and the melting point was 158 ° C.

The extruded foam sheet was cut into 270 mm (width direction) × 50 mm (extrusion direction), and the front and back surfaces were alternately cut with a cutter at intervals of 10 mm in the width direction. In addition, the thickness of the remaining part which was not cut in the site | part which gave the cut was about 0.1 mm in general. And the crease is alternately put on the front and back at the part of this cut, and the foam sheet in the shape of a bellows is fitted into a wooden frame with an internal dimension of 50 mm × 50 mm to form a board, and hot melt adhesive film (adhesive recommended temperature 125 ° C., An unstretched polypropylene resin film (thickness 30 μm) was laminated through a thickness of 40 μm, and heated for 5 minutes using a heating press set at 130 ° C. to form a 10 mm thick foam board. In addition, when heating, the space | interval of a press surface was 10 mm. The compression modulus of the obtained foam board was 320 N / mm ² .

(Example 2)
In the same manner as in Example 1, a polypropylene resin extruded foam sheet having an accordion-like shape was fitted into a wooden frame having an internal size of 50 mm × 50 mm to form a board, and this was sandwiched between release papers and set at 170 ° C. After preheating for 4 minutes with a press surface interval of 10 mm, the press surface interval is compressed to 8 mm and held for 1 minute, further cooled for 5 minutes with a cooling press with a press surface interval of 8 mm, and a foam board with a thickness of 8 mm Molded into. The compression modulus of the obtained foamed board was 340 N / mm ² .

(Comparative Example 1)
The polypropylene resin extruded foam sheet, hot melt adhesive film and unstretched polypropylene resin film of Example 1 were cut into 50 mm × 50 mm, and 5 foam sheets, 2 hot melt adhesive films and 2 polypropylene resin films were obtained. The thickness was approximately 10 mm, and the compression modulus was measured to find 280 N / mm ² .

(Example 3)
In the same manner as in Example 1, a polypropylene resin extruded foam sheet was obtained, cut into 135 mm (width direction) × 50 mm (extrusion direction), and cut with a cutter alternately on the front and back surfaces at intervals of 5 mm in the width direction. The foamed sheet with a crease and a bellows shape was fitted into a wooden frame with an inner size of 50 mm × 50 mm to form a board. Thereafter, a hot melt adhesive film and an unstretched polypropylene resin film were laminated in the same manner as in Example 1 and heated for 5 minutes with a press surface interval of 5 mm using a heating press set at 130 ° C., and foamed with a thickness of 5 mm. Molded into a board. The compression modulus of the obtained foam board was 350 N / mm ² .

Example 4
Using an extrusion laminating equipment, a propylene homopolymer (melt flow rate 9 g / 10 min at 230 ° C.) was extruded from a T-die into a film, and the extruded foam sheet and biaxially stretched film of Example 1 (thickness 25 μm and width) 1030 mm) was taken out while being crimped between two rolls to obtain a polypropylene-based resin laminated foam sheet in which the thickness of the non-foamed layer composed of the biaxially stretched film and the extruded resin was 100 μm.

This laminated foam sheet was folded into a bellows shape in the same manner as in Example 1, and formed into a 10 mm thick foam board using a hot melt adhesive film and an unstretched polypropylene resin film. The compression modulus of the obtained foamed board was 440 N / mm ² .

(Comparative Example 2)
The modified polypropylene resin laminated foam sheet, hot melt adhesive film and unstretched polypropylene resin film of Example 1 were cut into 50 mm × 50 mm, 5 foam sheets, 2 hot melt adhesive films, and polypropylene resin film 2 When the sheets were stacked to make the thickness approximately 10 mm and the compression modulus was measured, it was 270 N / mm ² .

(Example 5)
In place of the modified polypropylene resin of Example 1, a polystyrene resin (melt flow rate at 190 ° C., 1.5 g / 10 min) was used, and 0.5 part by weight of talc was used as a cell nucleus forming agent. An extruded foam sheet having a width of 1050 mm was obtained in the same manner as in Example 1 except that the set temperature of the extruder (150 mmφ) was 105 ° C. The density of the obtained extruded foamed sheet was 100 kg / m ³ , the closed cell ratio was 96%, the thickness was 2 mm, the basis weight was 0.2 kg / m ² , and the glass transition temperature was 101 ° C.

The above extruded foam sheet is cut into 250 mm (width direction) × 50 mm (extrusion direction), the front and back surfaces are alternately cut with a cutter at intervals of 10 mm in the width direction, and a creased foam sheet is formed. An unstretched polystyrene resin film (thickness 30 μm) was laminated on top and bottom via a hot-melt adhesive film (recommended adhesion temperature 80 ° C., thickness 40 μm) by fitting into a wooden frame with an internal size of 50 mm × 50 mm. This was heated for 5 minutes using a heating press set at 80 ° C. with a press surface interval of 10 mm, and formed into a 10 mm thick foam board. The compression modulus of the obtained foam board was 510 N / mm ² .

(Comparative Example 3)
The polystyrene resin extruded foam sheet, hot melt adhesive film and unstretched polystyrene resin film of Example 5 were cut into 50 mm × 50 mm, and 5 foam sheets, 2 hot melt adhesive films and 2 polypropylene resin films were obtained. The thickness was approximately 10 mm, and the compression modulus was measured to be 450 N / mm ² .

  By performing the method for producing a thermoplastic resin foam board according to the present invention, a thermoplastic resin foam having a rigidity higher than that of simply laminating with the same thickness direction of the thermoplastic resin foam sheet and the thickness direction of the thermoplastic resin foam board. It can be seen that a board can be obtained, and that the thickness of the thermoplastic resin foam board can be arbitrarily changed. Furthermore, the method in the present invention can produce a foam board using foam sheets of various resins.

It is a schematic perspective view of the thermoplastic resin foam board of this invention. It is a schematic perspective view of the thermoplastic resin foam board of this invention in which the skin part was formed with the face material. It is a schematic perspective view of the thermoplastic resin foam board of the present invention in which the skin portion is formed by heat fusion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermoplastic resin foam sheet 2 Skin part formed from face material 3 Edge part 4 Skin part formed by heat-fusion

Claims (3)

  In a thermoplastic resin foam board having a core part and skin parts above and below the core part, the core part is formed by laminating a plurality of thermoplastic resin foam sheets, and the surface of the thermoplastic resin foam sheet is thermoplastic. A thermoplastic resin foam board characterized by being oriented in the thickness direction of the resin foam board.   By folding the thermoplastic resin foam sheet at regular intervals, the thermoplastic resin foam sheet is laminated to form the core, and the face material is bonded to the surface composed of the ridges formed by folding the thermoplastic resin foam sheet. The method for producing a thermoplastic resin foam board according to claim 1, wherein a skin portion is formed.   By folding the thermoplastic resin foam sheet at regular intervals, the thermoplastic resin foam sheet is laminated to form the core, and the surface composed of the ridges formed by folding the thermoplastic resin foam sheet is heated and adjacent 2. The method for producing a thermoplastic resin foam board according to claim 1, wherein the ridge portions of the thermoplastic resin foam sheet are fused together to form a skin portion.

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