JP2004042500A - Laminated foam, its manufacturing method and swimming pool using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide laminated foam showing lightweight properties, and high rigidity withstanding local compression force and suitable for the side wall or bottom surface of a pool, a manufacturing method thereof and a swimming pool using the laminated foam. <P>SOLUTION: This laminated foam is obtained by laminating an FRP layer to at least one surface of core materials (preferably having slits provided on one surface), to which a surface material for suppresing foaming force in an in-plane direction generated at the time of thermal forming are laminated, on both surfaces of a polyolefinic resin foam (preferably a foaming expansion is 3-20 times and the average value of aspect ratio Dg/Dxy of internal foams is 1.1-4.0 and a compression elastic modulus is 6 MPa or more). <P>COPYRIGHT: (C)2004,JPO

Description

表１より明らかなように、本発明における実施例においては、発泡体密度が低い水準であっても、発泡体圧縮弾性率、積層体曲げ弾性率及び局部圧縮力が優れていることが判明した。
【００５８】
【発明の効果】
本発明の積層発泡体及びその製造方法においては、得られる積層発泡体が上述の如く高弾性率を有するため、軽量にして高い剛性を示し且つ局部的圧縮力にも耐え得る、特にプールの側壁又は底面用に好適な積層発泡体及びその製造方法を提供することができる。
【００５９】
また、本発明の水泳用プールは側壁や底面に上記積層発泡体が敷設されるので、上記同様の優れた性能を有するものとなる。
【図面の簡単な説明】
【図１】本発明の積層発泡体の一例を示す模式断面図である。
【図２】（Ａ）本発明における芯材の一例を示す模式上面図である。
（Ｂ）本発明における芯材の一例を示す模式横断面図である。
【符号の説明】
１　ポリオレフィン系樹脂発泡体（ポリプロピレン系樹脂発泡体）
２　面材
３　芯材
４１，４２　ＦＲＰ層
５　積層発泡体
６　スリット[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a laminated foam, a method for producing the same, and a swimming pool using the same, and more particularly, a laminated foam suitably laid for a side wall or a bottom surface of a pool, a method for producing the same, and a swim using the same. Regarding the pool.
[0002]
[Prior art]
BACKGROUND ART Conventionally, polyolefin-based resin foams have been widely used for various heat insulating materials, cushioning materials, flotation materials, and the like because of their excellent lightness, heat insulating properties, and flexibility.
[0003]
However, conventional polyolefin-based resin foams are compared with polystyrene-based resin foams in certain fields of use, such as rooftop insulation for buildings, flooring materials, floor coverings for automobiles, and side walls and bottom surfaces of pools. In addition, the compression elastic modulus and bending rigidity of the foam are small.
As an attempt to improve such a problem, for example, Japanese Patent Application Laid-Open No. 9-150431 discloses a two-dimensional foaming pressure generated in a plane when a foamable polyolefin-based resin sheet containing a pyrolytic foaming agent is heated and foamed. There is disclosed a composite foam in which a sheet having a strength capable of suppressing the pressure drop is laminated on at least one side.
[0004]
However, a sheet laminated on the polyolefin-based resin sheet and having a strength capable of suppressing an in-plane foaming pressure generated at the time of heating and foaming is usually relatively flexible in terms of its continuous productivity and has a small thickness. When a thin sheet material is used and receives a local compressive stress, the stress is not sufficiently dispersed, and the sheet material may be crushed or broken. For this reason, when high rigidity is required, for example, when the above-mentioned composite foam is used for a side wall or a bottom surface of a pool, sufficient performance has not always been obtained.
[0005]
On the other hand, in Japanese Patent Application Laid-Open No. 9-317224, a cushioning material is laid on the bottom of a pool, and a tile-like sheet is stuck on the cushioning material. The tile-like sheet includes a tile pattern portion and a joint portion. A swimming pool is disclosed in which the pattern portion and the joint portion are different colors, the joint portion depth is 0.1 to 1 mm, and the surface of the tile pattern portion has irregularities.
[0006]
However, in the above-mentioned swimming pool, even if the rigidity and the buffering property at the bottom surface are satisfactory, there are problems that the construction is troublesome, time is required for the construction period, and the variation in quality tends to be large.
[0007]
[Problems to be solved by the invention]
The present inventor has studied to solve the above-described conventional problems, and as a result, as a result, a laminated foam having a high rigidity foam and a fiber reinforced plastics layer (hereinafter, referred to as “FRP layer”) has been laminated. And have completed the present invention.
That is, an object of the present invention is to provide a laminated foam which is lightweight, exhibits high rigidity and can withstand local compressive force, and is particularly suitable for the side wall or bottom surface of the pool, a method for producing the same, and a swimming pool using the same. To provide.
[0008]
[Means for Solving the Problems]
In the laminated foam according to claim 1, a face material for suppressing an in-plane foaming force generated when heating and foaming is formed on both surfaces of a polyolefin resin foam in which individual cells are oriented in a thickness direction. An FRP layer is laminated on at least one surface of the laminated core material.
The laminated foam according to claim 2 is the laminated foam according to claim 1, wherein the expansion ratio of the polyolefin-based resin foam is 3 to 20 times, and the average value of the aspect ratio Dz / Dxy of the intrinsic cells. Is 1.1 to 4.0, and the compression modulus is 6 MPa or more.
A laminated foam according to a third aspect is the laminated foam according to the first or second aspect, wherein a slit is provided on at least one surface of the core material.
The method for producing a laminated foam according to claim 4 is the method for producing a laminated foam according to any one of claims 1 to 3, wherein the foamable polyolefin-based resin sheet containing a pyrolytic foaming agent is used. On both surfaces, a foamable composite sheet in which a face material for suppressing in-plane foaming force generated when the foamable polyolefin-based resin sheet is foamed by heating is laminated, at a temperature equal to or higher than the decomposition temperature of the pyrolytic foaming agent. It is characterized by including a step of heating and foaming to obtain a core material, and a step of laminating an FRP layer on at least one surface of the obtained core material.
A swimming pool according to a fifth aspect is characterized in that the laminated foam according to any one of the first to third aspects is laid on a side wall or a bottom surface.
[0009]
Hereinafter, the present invention will be described in detail.
In the present invention, a face material (hereinafter simply referred to as “face”) for suppressing the in-plane foaming force generated during heating and foaming is provided on both surfaces of a polyolefin resin foam in which individual cells are oriented in the thickness direction. Material) is used.
[0010]
The core material is, for example, a foamable polyolefin-based resin composition obtained by adding a pyrolytic foaming agent to a polyolefin-based resin and kneading the resulting foamable polyolefin-based resin composition to form a sheet. It is obtained by heating and foaming the foamable composite sheet having the face materials laminated thereon at a temperature equal to or higher than the decomposition temperature of the pyrolytic foaming agent.
[0011]
In the core material thus obtained, the face material laminated on both sides of the foamable polyolefin-based resin sheet suppresses the foaming force in the in-plane direction during foaming. Slightly expands and expands, foams only in the thickness direction of the expandable polyolefin resin sheet, and as a result, the cells constituting the obtained foam have a spindle shape with their major axis oriented in the thickness direction, The rugby balls are arranged as if they were upright in the same direction and arranged side by side, and are stacked in layers in the thickness direction.
[0012]
In the present invention, the in-plane direction refers to a two-dimensional direction defined by the longitudinal direction and the width direction of the polyolefin resin foam, and refers to a direction orthogonal to the thickness direction.
[0013]
The polyolefin-based resin constituting the polyolefin-based resin foam is not particularly limited. For example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, isotactic or syndetic Tactic homopolypropylene, block propylene copolymer, random propylene copolymer, polybutene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer, Ethylene-acrylate copolymers and the like can be mentioned. These may be used alone or in combination of two or more.
[0014]
In the polyolefin-based resin, other thermoplastic resins, for example, a compatible thermoplastic resin such as polystyrene, an elastomer or the like may be mixed and used in an amount of 30% by weight or less.
[0015]
The melt flow rate (MFR) of the above-mentioned polyolefin-based resin is preferably measured in accordance with JIS K7210, because the foam flow stability is reduced if the melt flow rate is too large or too low. The value is 0.1 to 20 g / 10 minutes.
[0016]
The polyolefin-based resin may be cross-linked as required. The method of crosslinking is not particularly limited, for example, an electron beam crosslinking method of irradiating ionizing radiation such as an electron beam, a chemical crosslinking method using an organic peroxide, or a silane-modified resin. Silane crosslinking method and the like.
[0017]
If the degree of cross-linking of the polyolefin resin is too high, the expansion ratio decreases, and the thermoformability decreases. If the degree is too low, the thermal stability decreases, and the cells (cell walls at the time of expansion) decrease. ) May be broken, and uniform bubbles may not be obtained. Therefore, the gel fraction serving as an indicator of crosslinking is preferably 10 to 30% by weight, more preferably 15 to 25% by weight.
[0018]
In the present invention, the gel fraction is a percentage (weight) of the residue weight after immersing the polyolefin resin foam in xylene at 120 ° C. for 24 hours with respect to the weight of the polyolefin resin foam before immersion in xylene. It is.
[0019]
The pyrolytic foaming agent is not particularly limited as long as it has a decomposition temperature equal to or higher than the melting temperature of the foamable polyolefin-based resin sheet, and includes, for example, sodium bicarbonate, ammonium carbonate, an azide compound, Inorganic pyrolytic foaming agents such as sodium borohydride, azodicarbonamide, azobisisobutyronitrile, N, N'-dinitrosopentamethylenetetramine, 4,4'-oxybisbenzenesulfonylhydrazide, azodicarboxylic acid Organic thermal decomposition type foaming agents such as barium, trihydrazinotriazine, p-toluenesulfonyl semicarbazide and the like can be mentioned. Above all, azodicarbonamide, which easily adjusts the decomposition peak temperature and decomposition rate, generates a large amount of gas, and is excellent in hygiene, is preferably used.
[0020]
The amount of the thermal decomposition type foaming agent to be added is determined according to the expansion ratio according to the intended use of the obtained laminated composite. Preferably, the amount is 0.1 to 20 parts by weight based on 100 parts by weight of the polyolefin-based resin because uniform bubbles are hardly formed.
[0021]
As a means for crosslinking the polyolefin resin, for example, in the case of an electron beam crosslinking method, a crosslinking aid such as divinylbenzene may be used.
The electron beam irradiation amount is preferably 1 to 20 Mrad, more preferably 3 to 10 Mrad.
[0022]
In the case of the silane crosslinking method, a crosslinking catalyst such as dibutyltin dilaurate and barium octoate may be used in addition to the silane-modified resin.
The amount of the crosslinking catalyst to be added is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 0.1 part by weight, based on 100 parts by weight of the polyolefin resin.
[0023]
The crosslinking agent used in the chemical crosslinking method is not particularly limited, and examples thereof include dibutyl peroxide, dicumyl peroxide, tertiary butyl cumyl peroxide, and diisopropyl peroxide. Among them, tertiary butyl cumyl peroxide and dicumyl peroxide are preferably used.
The amount of the crosslinking agent to be added is preferably 0.5 to 5 parts by weight, more preferably 1 to 3 parts by weight, based on 100 parts by weight of the polyolefin resin.
[0024]
The means for preparing a foamable polyolefin-based resin sheet from the foamable polyolefin-based resin composition to which the above-mentioned pyrolytic foaming agent has been added, comprises preparing the foamable polyolefin-based resin composition at a temperature lower than the decomposition temperature of the pyrolytic foaming agent. The sheet may be thermoformed into a sheet having a desired thickness, and examples of the thermoforming method include an extrusion method using a T-die and an inflation die, a press molding method, a calendar molding method, and a blow molding method. Among them, the extrusion molding method is suitably used from the viewpoint of productivity.
[0025]
In the present invention, the polyolefin-based resin foam, which is the main member of the core material, is one in which individual cells are oriented in the thickness direction, and the cells constituting the foam as described above are in the thickness direction. It has a spindle shape with its major axis oriented, and it is arranged like a rugby ball that stands upright in the same direction and arranged sideways, and has a structure laminated in layers in the thickness direction, and has high elasticity against compressive force in the thickness direction It shows the rate.
[0026]
In the case where the air bubble layer in which the air bubbles are arranged horizontally is stacked in multiple layers in the thickness direction, it is preferable that the density at the center portion in the thickness direction is lower than the density at the surface portion.
[0027]
The face material used in the present invention is not particularly limited as long as it can suppress the in-plane foaming force generated when the foamable polyolefin-based resin sheet is heated and foamed, as described above. For example, glass cloth woven glass fibers, glass mats formed by binding or binding glass fibers with a glass fiber, carbon cloths or carbon mats treated with carbon fibers like the above glass fibers, Woven fabrics made of natural fibers, synthetic fibers, etc., non-woven fabrics such as needle punching mats, knitted fabrics such as cold gauze, papers such as MF sheets, galvanized steel sheets, thin iron such as iron-zinc aluminum alloy sheets, stainless steel sheets And non-ferrous metal plates such as a thin metal plate, an aluminum plate, a titanium alloy plate, and a copper plate.
[0028]
The thickness of the face material is not particularly limited, but the viewpoint that the laminated composite of the present invention can be continuously manufactured in a long length by being compactly stored by means such as winding. From a metal plate or the like, it is preferably 1 mm or less, more preferably 0.3 mm or less.
The above-mentioned surface materials other than the flexible metal plate may have a thickness exceeding the above-mentioned thickness.
[0029]
The means for laminating the face material on the foamable polyolefin-based resin sheet is not particularly limited, and for example, a known laminator or the like is used.
[0030]
The heating and foaming means is not particularly limited.For example, a take-up device is provided at the exit side in a tunnel-type heating furnace using a heating medium such as hot air or a direct heating device such as an infrared heater. A method of foaming while transferring, a foaming method using an endless belt transfer device in place of the take-off device, a continuous foaming method such as a tunnel type heating furnace of a vertical type or a horizontal type, a hot air thermostat Or a foaming method using an oil bath, a metal bath, a salt bath, or the like instead of the heat medium such as hot air or a heat source.
[0031]
As described above, the core material obtained in this manner is such that the cells constituting the polyolefin-based resin foam are laterally aligned in a spindle shape in which the major axis is oriented in the thickness direction, and further, the layer is formed in the thickness direction. (See FIG. 1).
Therefore, the cells formed by the amount suppressed in the in-plane direction have a shape having a long axis in the thickness direction, thereby increasing the compression modulus. In addition, since the face materials are laminated, the elastic modulus of the core material is also increased by the reinforcing effect of the face materials themselves.
The orientation fraction of the major axis in the thickness direction of the foam cell is preferably 60% or more, more preferably 80% or more.
[0032]
The degree of orientation of the major axis in the thickness direction of the foam cell, that is, the ratio of the major axis to the minor axis, can be controlled by the expansion ratio and the melt viscosity of the expandable polyolefin-based resin composition.
In other words, since the expansion in the in-plane direction is suppressed by increasing the expansion ratio, the expansion in the thickness direction increases, and the ratio of the long axis to the short axis of the obtained foam cell increases.
[0033]
When the melt viscosity is less than 8000 poise, the melt viscosity of the expandable polyolefin resin composition is too low, so that the resin film of the cell ruptures during foaming and the spindle-shaped cells are not aligned beautifully, and have a good elastic modulus. When the above melt viscosity exceeds 25,000 poise, foaming is suppressed, the ratio of the long axis to the short axis of the obtained foam cell is small, and the desired compression modulus and flexural rigidity can be obtained. As a preferable foaming condition, for example, a foaming agent compounding to have a foaming ratio of 5 times or more in a melt viscosity range of 8000 to 25000 poise of the foamable polyolefin-based resin composition is exemplified.
[0034]
When the expansion ratio of the polyolefin-based resin foam is too low, a sufficient ratio of the major axis to the minor axis of the foamed cell cannot be obtained as described above, and not only a desired elastic modulus cannot be obtained, but also lightness is reduced. If it is lost, the cost increases, and if it exceeds 20 times, the ratio of the major axis to the minor axis of the foam cell becomes large enough, but the individual cell walls become thin, and the compressive modulus becomes insufficient. Preferably, the expansion ratio is 3 to 20 times, since it cannot be expressed.
[0035]
The average value of the aspect ratios Dz / Dxy of the intrinsic bubbles is preferably 1.1 to 4.0.
The above aspect ratio means the diameter of the foam cell in the z direction of the foam, that is, the diameter of the foam cell in the thickness direction of the foam, and the diameter of the foam cell in the width and length directions of the foam, that is, the in-plane direction of the foam. Represents Dz / Dxy when Dxy is defined as Dxy. When Dz / Dxy is less than 1.1, it may be difficult to obtain a desired compression modulus, and when Dz / Dxy exceeds 4.0. May cause excessive deformation of the polyolefin resin foam, which may make the production difficult.
[0036]
Further, the compression modulus is preferably 6 MPa or more, because if it is too small, buckling occurs with a slight load.
[0037]
In the present invention, if the core material has a slit (cut groove) on at least one side (see FIG. 2), the core material exhibits appropriate flexibility when laminating an FRP layer described in detail below, and air bubbles are generated. This is preferable in that entrapment of the film can be prevented. In this case, the shape of the slit is not particularly limited, but the depth is preferably about １ ／ to ／ of the thickness of the core material, and the groove width of the slit is preferably about 0.2 to 5 mm. The cross-sectional shape of the slit groove is not particularly limited, for example, a concave shape, a V-shape, or a U-shape. The arrangement and spacing of the slits on the surface of the core material are not particularly limited as long as the effects of the present invention are not impaired. For example, the slits are arranged in a grid in the vertical and horizontal directions of the core material surface, and the grid spacing is about 10 to 100 mm. It is preferable that The slit may be provided on one surface of the core material or may be provided on both surfaces.
[0038]
The method for producing the slit is not particularly limited, and, for example, a method of arranging a plurality of slit blades in the middle of a core material forming line and producing the slit in-line, or a core material cut and formed into a single sheet after molding. A method in which a plurality of slit blades are fed into a slitter provided with the slit blades to produce the slit blades, or the like, may be used.
As the slit blade, for example, an appropriate blade such as a saw blade or a knife can be used.
[0039]
When the slits are arranged in a grid pattern in the vertical and horizontal directions of the core material surface, for example, a method of feeding the core material to the slitter to prepare the slit, rotating the core material by 90 degrees, and feeding the slit material again to the slitter, or A method in which two slitters are used and arranged in a direction perpendicular to the slitter is used.
[0040]
In the present invention, an FRP layer is laminated on at least one surface of the core material.
The FRP is, for example, a so-called fiber-reinforced plastic obtained by curing a thermosetting resin such as an unsaturated polyester resin with fibers such as glass fibers.
[0041]
As the resin used for the FRP, conventionally known resins can be used and are not particularly limited. For example, unsaturated polyester resins, phenol resins, urea resins, polyurethane resins, epoxy resins, and the like are preferable. .
The fiber used for the FRP is not particularly limited, but, for example, glass fiber, carbon fiber, aramid fiber and the like are preferable.
[0042]
In the above description, the means for laminating and integrating the FRP layer on the core material is not particularly limited, and examples thereof include a method called a hand-re-up method and a method using an adhesive.
As the above hand-lay-up method, for example, a mat material or the like made of fiber such as glass fiber is laminated on a core material, and the room temperature-curable unsaturated polyester resin is impregnated into the mat material or the like using a roll or the like and cured. This is a method of stacking and integrating.
[0043]
On the other hand, as a method using an adhesive, for example, an FRP formed in a plate shape in advance by press molding or the like using an FRP material generally called SMC (sheet mold compound) is bonded and fixed to the above-mentioned core material via an adhesive. This is a method of stacking.
[0044]
The adhesive used in the above is not particularly limited. For example, a curable adhesive such as a urea resin adhesive, a melamine resin adhesive, a phenol resin adhesive, an epoxy resin adhesive, a polyurethane adhesive, a vinyl acetate resin Emulsion adhesive, vinyl acetate copolymer resin emulsion adhesive, acrylic emulsion adhesive, polyvinyl alcohol adhesive, polyvinyl alcohol adhesive, vinyl acetate resin mastic adhesive, dope cement, monomer cement, vinyl chloride resin adhesive, chloroprene rubber Emulsion adhesives such as adhesives, synthetic rubber latex adhesives, natural rubber adhesives, solvent adhesives or viscous solid adhesives, ethylene-vinyl acetate copolymer (EVA) hot melt adhesives, polyamides Hot melt adhesive, polyester Hot melt adhesives, various thermoplastic rubber adhesives, hot-melt adhesive such as a urethane hot melt adhesive.
[0045]
The method for producing the laminated foam is not particularly limited. For example, a foamable composite sheet having the face material laminated on both sides of a foamable polyolefin-based resin sheet containing a pyrolytic foaming agent is thermally decomposed. A method of laminating the above-mentioned FRP layer on one or both sides of the obtained core material, after heating and foaming the mold foaming agent or more to form a core material by foaming and forming a slit on the surface if necessary. It is suitable.
[0046]
In the swimming pool of the present invention, the laminated foam is laid on, for example, a side wall or a bottom surface of the pool.
[0047]
(Action)
In the laminated composite of the present invention, a face material for suppressing an in-plane foaming force generated during heating and foaming is laminated on both front and back surfaces of a polyolefin-based resin foam in which individual cells are oriented in a thickness direction. Since the FRP layer is laminated on at least one surface of the core material, the FRP layer laminated on the core material has high resistance to bending stress and the like in addition to the light weight and high compression modulus of the core material. Rigidity can be obtained.
[0048]
In the above, the expansion ratio of the polyolefin-based resin foam is 3 to 20 times, the average value of the aspect ratio Dz / Dxy of the intrinsic cells is 1.1 to 4.0, and the compression modulus is 6 MPa or more. Then, the above-described effect is further ensured.
[0049]
Further, when the core material is provided with a slit on at least one surface, the core material exhibits appropriate flexibility when laminating the FRP layer, and can prevent entrapment of air bubbles and the like, and is included in the FRP. When a material such as a thermosetting resin penetrates into the gap of the slit and is hardened, a decrease in the strength of the slit portion can be prevented, and the above-described effect is further ensured.
[0050]
The method for producing a laminated composite of the present invention is characterized in that a foamable composite sheet in which a specific face material is laminated on both sides of a foamable polyolefin-based resin sheet containing a pyrolytic foaming agent is used to decompose the pyrolytic foaming agent. In the step in which the core material is obtained by heating and foaming at a temperature higher than or equal to the temperature, a polyolefin resin foam in which individual cells are oriented in the thickness direction can be stably manufactured, and the FRP layer is laminated. In the above, since the material of the FRP layer and the lamination conditions can be appropriately adjusted according to the required strength, laminated composites having various qualities can be easily produced.
[0051]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to Examples and Comparative Examples.
The present invention is not limited only to the following examples.
(Examples 1 to 5)
[Preparation of core material]
A nonwoven fabric made of polyethylene terephthalate (Toyobo Co., Ltd.) is used as a surface material on both sides of an expandable polypropylene-based resin sheet containing azodicarbonamide as a thermally decomposable foaming agent as a surface material to suppress in-plane foaming force generated during heating and foaming. The foamable composite sheet obtained by laminating and unifying the product name of “Spanbond Ecool 6301A”) is foamed by heating at 230 ° C. for 8 minutes in a continuous foaming machine having a heating zone, as shown in FIG. A core material 3 in which a face material 2 was laminated on both surfaces of a polypropylene resin foam 1 was obtained. The thickness of the core material 3 was 15 mm.
[0052]
[Preparation of slit (see Fig. 2)]
Regarding Examples 1 to 4, the slits shown in Table 1 were formed in a lattice pattern at a predetermined pitch on one or both sides of the core material 3 using a cutter knife having a blade thickness of 0.6 mm ("NT cutter" manufactured by NTT Corporation). Produced.
[0053]
[Production of laminated foam (see FIG. 1)]
As a material of the FRP layer 41 on a molding die (not shown), a basis weight of 450 g / m ² 2 sheets of chopped strand glass fiber mat material (“Chopped Matt 450SE” manufactured by Nippon Electric Glass Co., Ltd.) are superposed and arranged at room temperature and cured at room temperature to be an unsaturated polyester resin (“Yupica 4075PT” manufactured by Nippon Yupika Co., Ltd.). The mat material is impregnated with an unsaturated polyester resin composition containing 1-2 parts of a room temperature curing peroxide as a reaction catalyst and cured at room temperature. ² Another layer of a chopped strand glass fiber mat material (trade name: “Chopped Mat 600SE” manufactured by Nippon Electric Glass Co., Ltd.) is superimposed, impregnated with an unsaturated polyester resin composition similar to the above, and then the above-mentioned non-saturated polyester resin The core material 3 coated with the saturated polyester resin is overlapped and pressed so that the surface coated with the unsaturated polyester resin is in contact with the mat material, and then cured at room temperature to form the FRP layer 41. Integrated.
[0054]
Next, on the core material 3 (the surface on which the FRP layer 41 is not laminated), as the material of the FRP layer 42, the same basis weight of 600 g / m 2 was used. ² The above-mentioned unsaturated polyester resin composition is impregnated into the above-mentioned mat material and cured at room temperature, and the FRP layers 41 and 42 are laminated and integrated on both surfaces of the core material 3. The laminated foam 5 was produced.
[0055]
(Comparative Examples 1-2)
The same as the above-described Example except that the core material (thickness: 15 mm) provided with the slits shown in Table 1 was used without using the face material 2 for suppressing the in-plane foaming force generated during heating and foaming. Similarly, a laminated foam was produced.
[0056]
The following evaluation was performed about the obtained laminated foam. The results are shown in Table 1.
[Evaluation method]
1. Measurement of aspect ratio
The polyolefin resin foam was cut in the thickness direction (z direction), and a 15-fold enlarged photograph was taken while observing the center of the cross section with an optical microscope. Next, after measuring the Dz and Dxy of all the bubbles in the photograph with a caliper, the Dz / Dxy of each bubble is calculated, the number average of Dz / Dxy for 100 bubbles is calculated, and the aspect ratio Dz / Dxy is calculated. The average value of Dxy was used. However, bubbles with an actual Dz of 0.05 mm or less and 10 mm or more were excluded.
2. Measurement of expansion ratio
The expansion ratio of the polyolefin resin foam was measured according to JIS K6767.
3. Foam compression modulus
The compression modulus of the polyolefin resin foam was measured according to JIS K7220.
4. Foam density
The density of the polyolefin resin foam was measured by the floatation method.
5. Laminate flexural modulus
A test piece was cut out from the laminated foam, and the strain and stress when a force was applied to the center of the test piece were measured in accordance with JIS A9511 to determine the flexural modulus.
6. Local compression test
A test piece is cut out from the laminated foam, and a weight is gently placed on the upper end of a press-fit rod having a diameter of 25 mm according to JIS A5914 so that a load of 200 N (20.4 kgf) is applied to the contact surface between the press-fit rod and the test piece. . The displacement of the press-fit rod after 1000 hours was measured with two dial gauges, and the average value was used to determine the amount of local compression.
7. Bubble entrapment
With respect to the state of bubble entrapment between the FRP layer of the laminated foam and the core material, the area ratio (%) of the projected area of the cell entrained portion to one surface area of the laminated foam was visually evaluated.
[0057]
[Table 1]

As is clear from Table 1, in the examples of the present invention, it was found that the foam compression elastic modulus, the laminate bending elastic modulus, and the local compressive force were excellent even at a low foam density. .
[0058]
【The invention's effect】
In the laminated foam of the present invention and the method for producing the same, since the obtained laminated foam has a high elastic modulus as described above, it is lightweight, exhibits high rigidity, and can withstand a local compressive force. Alternatively, a laminated foam suitable for a bottom surface and a method for producing the same can be provided.
[0059]
Further, the swimming pool of the present invention has the same excellent performance as the above because the laminated foam is laid on the side wall and the bottom surface.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing one example of a laminated foam of the present invention.
FIG. 2A is a schematic top view showing an example of a core material according to the present invention.
(B) It is a schematic cross section showing an example of a core material in the present invention.
[Explanation of symbols]
1 polyolefin resin foam (polypropylene resin foam)
2 face materials
3 core material
41, 42 FRP layer
5 laminated foam
6 slits

Claims (5)

At least one surface of a core material in which individual foams are laminated on both surfaces of a polyolefin resin foam in which a thickness direction is oriented, and a surface material for suppressing an in-plane foaming force generated when heating and foaming is laminated. And a fiber-reinforced plastic layer. The expansion ratio of the polyolefin-based resin foam is 3 to 20 times, the average value of the aspect ratio Dz / Dxy of the intrinsic cells is 1.1 to 4.0, and the compression modulus is 6 MPa or more. The laminated foam according to claim 1, wherein 3. The laminated foam according to claim 1, wherein a slit is provided on at least one surface of the core material. Foaming in which a foaming material for suppressing foaming force in an in-plane direction generated when the foamable polyolefin-based resin sheet is heated and foamed is laminated on both sides of a foamable polyolefin-based resin sheet containing a pyrolytic foaming agent. Heating the composite sheet to a temperature equal to or higher than the decomposition temperature of the pyrolytic foaming agent to form a core material, and laminating a fiber-reinforced plastic layer on at least one surface of the obtained core material. The method for producing a laminated foam according to any one of claims 1 to 3, characterized in that: A swimming pool comprising the laminated foam according to claim 1 laid on a side wall or a bottom surface.

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