JP6683982B2 - Resin laminated sheet and molded products - Google Patents

Description

  The present invention relates to a resin laminated sheet and a molded product thereof.

  BACKGROUND ART A resin sheet material has excellent moldability and is relatively inexpensive, so that it is widely used for applications such as food containers. It is preferable that the food container does not easily slip off when held by a hand, and a food container designed to prevent slippage is disclosed in, for example, JP-A-2015-63326 (Patent Document 1). The container of Patent Document 1 has irregularities formed on its outer surface so as to have a depth of 150 to 450 μm at intervals of 1000 to 3000 μm. By making it easy to catch a finger on the unevenness of the outer surface of the container, the container is prevented from slipping off.

  The technique of Patent Document 1 physically exerts an anti-slip effect by devising the outer surface shape of the container formed by sheet molding. However, for that purpose, it is necessary to prepare a die for forming a sheet according to the shape of the outer surface of the container, which leads to an increase in cost. In addition, the container of Patent Document 1 has a drawback that the appearance is not good due to the presence of clear (macro) irregularities on the outer surface. Therefore, in order to exert the anti-slip effect regardless of the shape of the outer surface of the container, the sheet material which is the base of the container is required to be improved in terms of material.

JP, 2005-63326, A

  It is desired to realize a resin sheet that can improve the non-slip properties and the appearance when a molded product is formed by sheet molding by improving the material.

The resin laminated sheet according to the present invention,
A thermoplastic resin layer, and a polystyrene resin non-foamed layer laminated on at least one surface of the thermoplastic resin layer,
The constituent material of the polystyrene resin non-foamed layer contains 50 to 90% by weight of polystyrene resin and 50 to 10% by weight of polyolefin resin,
The static friction coefficient of the surface of the polystyrene resin non-foamed layer is 0.8 or more, the arithmetic average roughness is 1.4 μm or more, and the glossiness is 12% or less.

  According to this configuration, the static friction coefficient of the surface of the polystyrene resin non-foamed layer is 0.8 or more, and the arithmetic average roughness is 1.4 μm or more, so that the slip resistance on the surface can be improved. . Further, by forming the polystyrene-based resin non-foamed layer with a material containing 50 to 90% by weight of the polystyrene-based resin and 50 to 10% by weight of the polyolefin-based resin, the glossiness becomes 12% or less, and is unique. It is possible to develop designability. Therefore, the appearance of the surface of the polystyrene resin non-foamed layer can be improved. As described above, by using the resin laminated sheet having the above configuration, it is possible to improve the anti-slip property and the appearance when a molded product is formed by sheet molding.

  Hereinafter, preferred embodiments of the present invention will be described. However, the scope of the present invention is not limited by the preferred embodiments described below.

As one aspect,
It is preferable that the constituent material of the polystyrene resin non-foamed layer further contains 0 to 10% by weight of a styrene thermoplastic elastomer.

  According to this configuration, the appearance of the surface of the polystyrene resin non-foamed layer can be further improved.

The molded article according to the present invention,
The resin laminated sheet is thermoformed so that the polystyrene resin non-foamed layer is the outermost layer.

  According to this configuration, it is possible to improve the slip resistance and the appearance of the outer surface of the molded product. Therefore, the appearance of the molded product can be improved, and it is easy to avoid the situation where the molded product is dropped by sliding the hand.

  Further features and advantages of the invention will become more apparent from the following description of exemplary and non-limiting embodiments described with reference to the drawings.

Schematic cross section of resin laminated sheet Schematic perspective view of container Schematic cross section of container Schematic perspective view of cut sheet pieces Schematic diagram showing the method of measuring the coefficient of static friction Electron micrograph of the sheet surface of Example 3 Electron micrograph of the sheet surface of Comparative Example 3

  Embodiments of a resin laminated sheet and a container will be described with reference to the drawings. The container 10 of the present embodiment is, for example, a container (food packaging container) for packaging food (an example of a contained object) such as a bowl or a side dish. The container 10 is formed by sheet molding of a resin laminated sheet 1 formed by laminating resin sheets.

  As shown in FIG. 1, the resin laminated sheet 1 of the present embodiment includes a thermoplastic resin layer 2 and a polystyrene resin non-foamed layer 3 laminated on one surface of the thermoplastic resin layer 2. The resin laminated sheet 1 of the present embodiment further includes a polypropylene resin non-foamed layer 4 laminated on the other surface of the thermoplastic resin layer 2.

  The thermoplastic resin layer 2 is a layer serving as a base material of the resin laminated sheet 1. The thermoplastic resin layer 2 is mainly composed of a thermoplastic resin. The thermoplastic resin forming the thermoplastic resin layer 2 is not particularly limited. For example, general thermoplastic resins such as polyolefin (polyethylene, polypropylene, etc.), polyvinyl chloride, polystyrene, polyester (polyethylene terephthalate, etc.), and acrylic resin can be used as appropriate. These may each be a homopolymer, a copolymer with another monomer, a mixture with another resin, or a combination thereof. Moreover, the thermoplastic resin layer 2 may be a foamed layer or a non-foamed layer.

  A preferable example of the thermoplastic resin layer 2 is a polypropylene resin foam layer from the viewpoint of heat resistance and heat insulation. The polypropylene-based resin foam layer is a foam layer mainly composed of polypropylene resin. The polypropylene-based resin forming the polypropylene-based resin foam layer is not particularly limited, and examples thereof include a homopolymer of propylene, a copolymer of propylene and another monomer, or a mixture of propylene and another resin. Good. Further, as the polypropylene resin, a resin containing a polypropylene resin having strain hardening property can be preferably used. Here, "strain hardening" means the characteristic that the extensional viscosity of the polypropylene-based resin rapidly increases as the strain rate increases. As an example of the polypropylene resin having a strain-hardening property, a polypropylene resin in which a branched structure is introduced into a molecular chain by electron beam irradiation or chemical cross-linking, or entanglement of molecular chains by mixing an ultrahigh molecular weight component An example is an enlarged polypropylene resin.

  The polypropylene-based resin may include only the above-described strain-hardening polypropylene-based resin, or may be a mixture with a strain-free polypropylene-based resin. As an example of the polypropylene resin having no strain hardening property, a commercially available general linear polypropylene resin can be mentioned.

  When the constituent materials of the thermoplastic resin layer 2 (polypropylene resin foam layer) include both strain-curable polypropylene resin and strain-uncurable polypropylene resin, the compounding ratio thereof is% by weight. As a standard, it can be set to 60:40 to 100: 0. By setting the content of the strain-hardening polypropylene resin to 60% by weight or more, a foam having a high closed cell rate can be obtained, and heat resistance and mechanical strength can be improved. A preferable example of the content of the strain-hardening polypropylene resin in the constituent material of the thermoplastic resin layer 2 (polypropylene resin foam layer) is 100% by weight.

  The thermoplastic resin layer 2 may contain a trace amount of additives, if necessary. Examples of the additive include an antioxidant, an ultraviolet absorber, a stabilizer, a nucleating agent, a lubricant, a filler, a reinforcing material, a pigment, a dye, a flame retardant, and an antistatic agent.

  The thickness of the thermoplastic resin layer 2 is not particularly limited, but may be 0.3 to 5 mm, for example. If the thickness of the thermoplastic resin layer 2 is thinner than 0.3 mm, the rigidity and heat insulating property may be insufficient, and if it is thicker than 5 mm, the moldability may be insufficient. The thickness of the thermoplastic resin layer 2 is preferably 0.6 to 3 mm, more preferably 0.8 to 2.4 mm.

  The closed cell ratio in the case where the thermoplastic resin layer 2 is a foamed layer is not particularly limited, but may be 60% or more, for example. If the closed cell ratio is less than 60%, the rigidity and heat insulating property may be insufficient. The closed cell ratio is preferably 70% or more, more preferably 80% or more. The bubble diameter of the bubbles contained in the thermoplastic resin layer 2 is not particularly limited, but may be, for example, 8 to 300 μm, preferably 10 to 220 μm.

  Further, the number of bubbles per 1 mm in thickness when the thermoplastic resin layer 2 is a foam layer is not particularly limited, but may be, for example, 10 to 30. If the number of bubbles per unit thickness is less than 10, the heat insulating property may be insufficient, the smoothness of the sheet surface may be impaired, and the appearance may deteriorate, and the polystyrene resin non-foamed layer 3 The polypropylene resin non-foamed layer 4 may be difficult to be laminated. On the contrary, when the number exceeds 30 and becomes large, brittleness may occur and moldability may become insufficient. The number of bubbles per unit thickness is preferably 15 to 20.

  The polystyrene-based resin non-foaming layer 3 is a non-foaming layer mainly composed of polystyrene-based resin. Polystyrene-based resin The polystyrene-based resin constituting the non-foamed layer 3 is not particularly limited, but for example, a homopolymer of styrene, a copolymer of styrene and another monomer, a mixture of polystyrene and another resin, or the like. May be Examples of other monomers and other resins include polyolefin resins, urethane resins, and acrylic resins. Above all, a mixture with a polyolefin resin can be preferably used, and the constituent material of the polystyrene resin non-foamed layer 3 preferably contains a polystyrene resin and a polyolefin resin.

  In this case, the compounding ratio of the polystyrene resin and the polyolefin resin can be 50:50 to 90:10 on a weight% basis. By containing 50% by weight or less of the polyolefin-based resin, it is possible to develop a unique design property of a soft and warm texture as compared with the non-foamed layer of the polystyrene-based resin alone. On the other hand, when the content of the polyolefin-based resin is less than 10% (that is, when the content of the polystyrene-based resin is more than 90% by weight), the polystyrene-based resin non-foamed layer 3 is easily peeled from the thermoplastic resin layer 2. Could be. A more preferable mixing ratio of the polystyrene resin and the polyolefin resin is 55:45 to 85:15 on a weight% basis.

  In the above case, high impact polystyrene (HIPS) may be used as the polystyrene resin.

  The constituent material of the polystyrene resin non-foamed layer 3 may further contain a styrene thermoplastic elastomer. The styrene-based thermoplastic elastomer is not particularly limited, for example, styrene-butadiene-styrene block copolymer (SBS) or a hydrogenated product thereof, styrene-isoprene-styrene block copolymer (SIS) or a hydrogenated product thereof, Styrene-isobutylene-styrene block copolymer (SIBS), styrene-ethylene-butadiene-styrene copolymer (SEBS), styrene-ethylene-propylene copolymer (SEP), and styrene-ethylene-propylene-styrene copolymer. (SEPS) or the like can be used.

  Further, for example, it is preferable that the constituent material of the polystyrene resin non-foamed layer 3 includes a polystyrene resin, a styrene thermoplastic elastomer, and a polyolefin resin. In this case, the polystyrene resin is preferably 50 to 85% by weight, the styrene thermoplastic elastomer is 0 to 10% by weight, and the polyolefin resin is preferably 50 to 10% by weight. The preferred composition is 55 to 85% by weight of polystyrene resin, about 5% by weight of styrene thermoplastic elastomer, and 40 to 10% by weight of polyolefin resin.

  The polystyrene-based resin non-foamed layer 3 may contain a small amount of additives as necessary. Examples of the additive include an antioxidant, an ultraviolet absorber, a stabilizer, a nucleating agent, a lubricant, a filler, a reinforcing material, a pigment, a dye, a flame retardant, and an antistatic agent.

  The thickness of the polystyrene resin non-foamed layer 3 is not particularly limited, but may be, for example, 5 to 200 μm. If the thickness of the polystyrene-based resin non-foamed layer 3 is smaller than 5 μm, the effect of improving the designability by stacking the polystyrene-based resin non-foamed layer 3 may be insufficient. On the other hand, if it is thicker than 200 μm, the moldability may be insufficient, and the raw material cost will increase. The thickness of the polystyrene-based resin non-foamed layer 3 is preferably 5 to 100 μm, more preferably 10 to 50 μm.

  In the resin laminated sheet 1 of the present embodiment, the static friction coefficient of the surface of the polystyrene resin non-foamed layer 3 is 0.8 or more. Here, the static friction coefficient of the surface of the polystyrene-based resin non-foamed layer 3 is a value obtained by measurement according to JIS K 6253-3: 2012. If the coefficient of static friction is 0.8 or more, in order to slide the resin laminated sheet 1 in the surface direction while touching the surface of the polystyrene-based resin non-foamed layer 3 in the resin laminated sheet 1, a large amount of external force is required. Is required. To put it the other way around, the resin laminated sheet 1 does not easily slide in the surface direction, and the slip resistance on the surface of the polystyrene-based resin non-foamed layer 3 can be improved. The static friction coefficient of the surface of the polystyrene resin non-foamed layer 3 is preferably 0.8 to 0.9.

  The arithmetic average roughness of the surface of the polystyrene resin non-foamed layer 3 is 1.4 μm or more. Here, the arithmetic mean roughness of the surface of the polystyrene-based resin non-foamed layer 3 is a value obtained by measurement according to JIS B 0601-3: 2001. If the arithmetic average roughness is 1.4 μm or more, minute (micro) unevenness is formed on the surface of the polystyrene-based resin non-foamed layer 3 and it becomes difficult to slip. Therefore, in combination with the static friction coefficient of the surface of the polystyrene resin non-foamed layer 3 being 0.8 or more, the slip resistance on the surface can be effectively improved. Since the unevenness is not directly visible on the order of microns, there is no inconvenience that the unevenness makes the appearance worse. The arithmetic average roughness of the surface of the polystyrene resin non-foamed layer 3 is preferably 1.4 to 1.8 μm.

  The glossiness of the surface of the polystyrene resin non-foamed layer 3 is 12% or less. Here, the glossiness of the surface of the polystyrene resin non-foamed layer 3 is a value obtained by measurement according to Method 3 (60-degree specular gloss) in JIS Z8741. When the glossiness is 12% or less, the surface of the polystyrene-based resin non-foamed layer 3 is appropriately matted to improve the design. In particular, in combination with the soft and warm texture due to the compounding ratio of the polystyrene resin and the polyolefin resin forming the polystyrene resin non-foamed layer 3 being 50:50 to 90:10 on a weight% basis, A unique design can be expressed. The glossiness of the surface of the polystyrene resin non-foamed layer 3 is preferably 11% or less, and more preferably 8 to 11%.

  The polypropylene-based resin non-foaming layer 4 is a non-foaming layer mainly composed of polypropylene resin. Polypropylene resin The polypropylene resin that constitutes the non-foamed layer 4 is not particularly limited, but for example, a homopolymer of propylene, a copolymer of propylene and another monomer, or a mixture of polypropylene and another resin, etc. May be

  The polypropylene-based resin non-foamed layer 4 may contain a small amount of additives as necessary. Examples of the additive include an antioxidant, an ultraviolet absorber, a stabilizer, a nucleating agent, a lubricant, a filler, a reinforcing material, a pigment, a dye, a flame retardant, and an antistatic agent.

  The thickness of the polypropylene resin non-foamed layer 4 is not particularly limited, but may be, for example, 5 to 200 μm. If the thickness of the polypropylene resin non-foamed layer 4 is less than 5 μm, the smoothness of the sheet surface may be impaired. On the other hand, if it is thicker than 200 μm, the moldability may be insufficient, and the raw material cost will increase. The thickness of the polypropylene resin non-foamed layer 4 is preferably 20 to 100 μm, more preferably 30 to 80 μm.

  The method for manufacturing the resin laminated sheet 1 includes a melting step, a foaming step, a sheet forming step, and a laminating step. In the melting step, the resin raw material for each layer is heated and melted. In the foaming step, the molten resin of the thermoplastic resin layer 2 (polypropylene resin foam layer in this example) is foamed. As the foaming agent added at that time, for example, hydrocarbons, carbon dioxide, nitrogen, air, water and the like can be used, and two or more of these may be used in combination. In the sheet forming step, a sheet is formed from the molten resin of each layer using, for example, an extruder. In the laminating step, the sheets of each layer are laminated. The sheet forming process and the laminating process may be sequentially performed as separate processes, or may be performed simultaneously. That is, the sheets of the respective layers may be formed in advance and then laminated, or the sheets of the respective layers may be extruded and laminated at the same time. In any case, the resin laminated sheet 1 (polypropylene resin foam laminated sheet in this example) can be obtained through the above steps.

  The total thickness of the resin laminated sheet 1 is not particularly limited, but it depends on the respective thicknesses of the thermoplastic resin layer 2, the polystyrene-based resin non-foaming layer 3, and the polypropylene-based resin non-foaming layer 4, and is, for example, 0. It may be 5 to 5.5 mm. The total thickness of the resin laminated sheet 1 is preferably 1 to 3 mm.

The overall density of the resin laminated sheet 1 is not particularly limited, but may be, for example, 0.15 to 0.85 g / cm ³ . If the overall density is less than 0.15 g / cm ^3, the strength and rigidity at high temperature when molded into a molded product may be insufficient, and if it is greater than 0.85 g / cm ³ , the molded product is There is a possibility that the heat insulation when molded is insufficient. The overall density of the resin laminated sheet 1 is preferably 0.21 to 0.55 g / cm ³ , and more preferably 0.25 to 0.35 g / cm ³ .

  According to the resin laminated sheet 1 of this embodiment, the non-foamed polystyrene resin layer 3 having a specific composition is laminated on the thermoplastic resin layer 2, and the physical properties of the non-foamed polystyrene resin layer 3 are adjusted to prevent slippage. It is possible to improve the sex and appearance.

  By carrying out thermoforming using such a resin laminated sheet 1, a molded article (for example, the container 10 shown in FIG. 2) having improved slip resistance and appearance on the outer surface can be obtained. The container 10 includes a bottom surface portion 11 that forms a bottom portion, a peripheral wall portion 12 that extends upward from the peripheral edge of the bottom surface portion 11, and a flange portion 13 that extends outward from the upper end of the peripheral wall portion 12. . Although FIG. 2 shows an example in which the container 10 is formed in a circular shape in a plan view, the container 10 is not limited to such a configuration, and the container 10 is formed in an oval shape or a polygonal shape in a plan view. May be done. Further, even if the bottom surface portion 11 and the flange portion 13 are different from each other in plane view shape such that the bottom surface portion 11 is formed in a polygonal shape in plan view and the flange portion 13 is formed in a circular shape in plan view. good.

  Here, when thermoforming the container 10, as shown in FIG. 3, the resin laminated sheet 1 is arranged such that the polystyrene resin non-foamed layer 3 is the outermost layer. In this way, the slip resistance and appearance of the outer surface of the container 10 can be improved. Therefore, it is possible to improve the design of the outer appearance of the container 10 and to easily avoid a situation where the container 10 is dropped by sliding a hand. Further, in this configuration, since the polypropylene resin non-foamed layer 4 is the innermost layer, the oil resistance of the inner surface of the container 10 can be improved.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited by the specific examples described below.

[Example 1]
As a resin material for the polypropylene-based resin foam layer (an example of a thermoplastic resin layer; the same applies below), EX4000 (100% by weight) manufactured by Japan Polypro Co., Ltd. was prepared, and 100 parts by weight thereof was used as a nucleating agent by Eiwa Chemical. EE275F manufactured by Kogyo Co., Ltd. was added at a ratio of 2.6 parts by weight, and uniformly mixed with a ribbon blender. As a resin material for the polystyrene resin non-foamed layer, HI408 manufactured by PS Japan Co., Ltd., BC3BRF manufactured by Japan Polypro Co., Ltd. and TR2003 manufactured by JSR Co., Ltd. were prepared at a weight ratio of 55: 40: 5. These were mixed uniformly with a ribbon blender. As a resin material for the polypropylene resin non-foamed layer, BC3BRF (100% by weight) manufactured by Japan Polypro Co., Ltd. was prepared.

  As an extruder for the polypropylene-based resin foam layer, one 40 mmφ twin-screw extruder (manufactured by Plastic Engineering Laboratory Co., Ltd., model: RT-40-S2-36-L, L / D = 36) was prepared. As an extruder for the polystyrene resin non-foamed layer and the polypropylene resin non-foamed layer, two 40 mmφ single screw extruders (manufactured by GM Engineering Co., model: VGM40-25, L / D = 25) were used. Got ready. The tips of these extruders were attached to a two-kind three-layer feed block (made by Krollen Japan Co., Ltd., model: Krollen FG feed block), and a T die was attached to this feed block.

  Cylinder temperature of the twin-screw extruder for the polypropylene resin foam layer is 200 to 230 ° C, cylinder temperature of the single-screw extruder for the polystyrene resin non-foam layer is 210 ° C, single-screw extrusion for the polypropylene resin non-foam layer The cylinder temperature of the machine was set to 210 ° C., and the resin material was supplied to the hopper of each extruder and melted. Carbon dioxide (liquefied carbon dioxide gas) was injected as a foaming agent into the cylinder of the twin-screw extruder for the polypropylene resin foam layer, and the mixture was further kneaded.

  Under atmospheric pressure, a three-layer sheet was extruded by laminating a polypropylene resin non-foamed layer, a polypropylene resin foamed layer, and a polystyrene resin non-foamed layer by a coextrusion method. The three-layer sheet-like material was passed through a water-cooling roll adjusted to 25 ° C. and rapidly cooled to obtain a polypropylene resin foam laminated sheet.

  Further, a molded product was produced from the obtained polypropylene resin foam laminated sheet using a small vacuum pressure air molding machine (manufactured by Wakisaka Engineering Co., Ltd., model: FVS-500). The polypropylene resin foam laminated sheet is fixed with a clamp of 50 × 40 cm, heated with a heater at a set temperature of 300 ° C. for about 15 seconds from the top and bottom, and then a bowl type of 165 × 165 × 56 mm is formed by a differential pressure forming method. I got a container. At that time, thermoforming was performed so that the polystyrene resin non-foamed layer was on the outside of the container and the polypropylene resin non-foamed layer was on the inside of the container.

[Example 2]
In the same manner as in Example 1 except that the composition of the resin material of the polystyrene resin non-foamed layer was HI408: BC3BRF: TR2003 = 65: 30: 5 (wt%), a polypropylene resin foam laminated sheet and A molded product was obtained.

[Example 3]
A polypropylene resin foam laminated sheet and a polypropylene resin foam laminated sheet were prepared in the same manner as in Example 1 except that the composition of the resin material of the polystyrene resin non-foamed layer was HI408: BC3BRF: TR2003 = 70: 25: 5 (wt%). A molded product was obtained.

[Example 4]
In the same manner as in Example 1 except that the composition of the resin material of the polystyrene resin non-foamed layer was HI408: BC3BRF: TR2003 = 75: 20: 5 (wt%), a polypropylene resin foam laminated sheet and A molded product was obtained.

[Example 5]
In the same manner as in Example 1 except that the composition of the resin material of the polystyrene resin non-foamed layer was HI408: BC3BRF: TR2003 = 85: 10: 5 (wt%), a polypropylene resin foam laminated sheet and A molded product was obtained.

[Comparative Example 1]
In the same manner as in Example 1 except that the composition of the resin material of the polystyrene resin non-foamed layer was HI408: BC3BRF: TR2003 = 45: 50: 5 (wt%), a polypropylene resin foam laminated sheet and A molded product was obtained.

[Comparative Example 2]
A polypropylene resin foam laminated sheet and a polypropylene resin foam laminated sheet were prepared in the same manner as in Example 1 except that the composition of the resin material of the polystyrene resin non-foamed layer was HI408: BC3BRF: TR2003 = 90: 5: 5 (wt%). A molded product was obtained.

[Comparative Example 3]
A polypropylene resin foam laminated sheet and a molded article were prepared in the same manner as in Example 1 except that the polypropylene resin non-foamed layer was provided on both surfaces of the polypropylene resin non-foamed layer. Obtained.

[Evaluation]
Regarding the polypropylene resin foam laminated sheets of Examples 1 to 5 and Comparative Examples 1 to 3, the thickness of the entire sheet, the thickness of the non-foamed layer, the density of the entire sheet, the closed cell ratio, the number of cells per unit thickness, and the surface roughness. , Static friction coefficient, and glossiness were measured. In addition, the molded articles of Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated for anti-slip property and appearance. Further, electron micrographs of the sheet surfaces of the polypropylene resin foam laminated sheets of Example 3 and Comparative Example 3 were taken.

<Thickness of entire sheet, thickness of non-foamed layer, number of bubbles per unit thickness>
A test piece with a size of 120 mm × 120 mm was cut out from a polypropylene resin foam laminated sheet, and a cross section in the thickness direction was photographed with a scanning electron microscope (manufactured by JEOL Ltd., model: JCM-6000Plus) at a magnification of 40 times. did. In the photographed image, the thickness of the test piece is measured at four places (three places at intervals of 30 mm shown by black triangles in FIG. 4) that divide the test piece into four equal parts in the width direction, and an average value thereof is calculated to obtain the total sheet thickness. did. In addition, in the photographed image, the shortest distance from the sheet surface to the peripheral edge of the bubble at the above-mentioned location was measured, and the average value thereof was determined to be the thickness of the non-foamed layer. Also, in the photographed image, the number of bubbles that overlap the perpendicular line along the thickness direction at the above-mentioned location is counted, the average value thereof is divided by the thickness of the entire sheet, and the number after the decimal point is rounded off, and the number of bubbles per unit thickness. And

<Density>
A 40 mm × 40 mm test piece was cut out from the polypropylene-based resin foam laminated sheet, and the density was measured by an underwater displacement method using an electronic hydrometer (Model: ED-120T, manufactured by Mirage Trading Co., Ltd.).

<Closed cell ratio>
Test pieces of 30 mm x 40 mm in size are cut out from the polypropylene-based resin foam laminated sheet at positions (3 locations) that are almost even in the width direction, and the electronic balance (Shimadzu Corporation, model: AUW220) and thickness measurement The weight and volume of the test piece were measured using a gauge (Digimatic caliper manufactured by Mitutoyo Corporation, model: CD-10CX). A stack is formed by stacking three test pieces and using an air-comparison hydrometer (manufactured by Tokyo Science Co., Ltd., model: 1000) by the 1-2-1 atmospheric pressure method according to ASTM D-2856. Was measured and the closed cell ratio was calculated by the following formula.
Closed cell ratio [%] = (Vx−Vw) / (Va−Vw) × 100
Here, Vx is the volume [cm ³ ] of the laminated body by the air-comparison hydrometer, Vw is the total weight [g] / specific gravity [g / cm ³ ] of the ^three test pieces, and Va is 3 pieces. Is the total volume (apparent volume) [cm ³ ] of the test piece.

<Surface roughness>
A test piece is cut out from a polypropylene-based resin foamed laminated sheet, and a polystyrene-based resin is not foamed in accordance with JIS B 0601-3: 2001 using a surface roughness measuring instrument (Surfcom manufactured by Tokyo Seimitsu Co., Ltd., model: 1400D). The arithmetic mean roughness Ra of the surface of the layer was measured. In the measurement, the radius of curvature of the tip of the tracing stylus was 2 μm, and the measurement was performed at a speed of 0.06 mm / s in a range of 4.0 mm along the direction orthogonal to the extrusion direction. The cutoff value was 0.8 mm. Each measurement was performed 3 times, and the average value of the measurement results was adopted. In Comparative Example 3, the same measurement was performed on the surface of the polypropylene resin non-foamed layer.

<Static friction coefficient>
A test piece measuring 63 mm × 63 mm was cut out from the polypropylene resin foam laminated sheet. Further, a fluororubber sheet having a hardness of 78 and a thickness of 2 mm (Kreha Elastomer Co., Ltd., product number: FB780N) according to JIS K 6253: 2012 was prepared. As shown in FIG. 5, a fluororubber sheet 101 was fixed to a test stand, and a test piece 102 (sliding piece) was placed on the non-foamed polystyrene resin layer (in Comparative Example 3, one polypropylene resin nonfoamed layer). The layer 103 was placed so as to face downward, and the weight 103 was further placed thereon. In this state, the test piece 102 is pulled by the indexing thread 104 attached to the test piece 102, the tension immediately before the test piece 102 starts to slide is measured by the load cell 105 attached to the other end of the indexing thread 104, and the static friction force is measured. (Fs). Based on this static friction force (Fs) and the normal force (Fp) due to the total mass of the test piece 102 and the weight 103, the static friction force (Fs) divided by the normal force (Fp) is the static friction coefficient (μ _s ). (Μ _s = Fs / Fp).

<Glossiness>
A test piece is cut out from a polypropylene-based resin foam laminated sheet, and using a handy gloss meter (HORIBA, Ltd. gloss checker, model: IG-320) in accordance with JIS Z 8741 Method 3 (60-degree specular gloss), The glossiness of the surface of the non-foamed polystyrene resin layer was measured. In Comparative Example 3, the same measurement was performed on the surface of the polypropylene resin non-foamed layer.

<Slip resistance>
The obtained molded product was evaluated for ease of holding when held by hand. Those that could be held satisfactorily were rated as “◯”, those that were inferior were rated as “x”, and those that could not be described as “Δ”.

<Appearance>
The outer surface of the obtained molded product was visually observed to evaluate the presence or absence of gloss and the texture. Those with a soft texture and whose gloss was suppressed were rated as "○", those with a hard texture that gave a gloss were rated as "X", and those that could not be described as "△".

<Electron micrograph>
A test piece with a size of 120 mm × 120 mm was cut out from the polypropylene resin foam laminated sheet, and the surface of the polystyrene resin non-foamed layer was photographed with a scanning electron microscope (manufactured by JEOL Ltd., model: JCM-6000Plus). Taken at 100x. In Comparative Example 3, the same photographing was performed on the surface of the polypropylene resin non-foamed layer.

  The above results are summarized in Table 1 and FIGS. 6 and 7. In Table 1, "PP foam layer" represents a polypropylene resin foam layer, "PS non-foam layer" represents a polystyrene resin non-foam layer, and "PP non-foam layer" represents a polypropylene resin non-foam layer. Represent Moreover, "wt%" represents weight% and "part" represents part by weight.

  As is clear from Table 1, the molded products of Examples 1 to 5 were excellent in anti-slip property and appearance. On the other hand, the molded articles of Comparative Examples 1 to 3 had insufficient or at least one of the non-slip property and the appearance, and were obviously inferior. Comparing the results of Comparative Example 3 with the results of Examples 1 to 5, it was found that good non-slip properties and appearance were imparted by laminating the polystyrene resin non-foamed layer on the polypropylene resin foamed layer. I understand. Further, when the results of Comparative Examples 1 and 2 are compared with the results of Examples 1 to 5, good slip resistance can be obtained only when the composition of the polystyrene resin non-foamed layer laminated on the polypropylene resin foamed layer is a specific composition. It can be seen that the property and the appearance are imparted.

  When comparing the electron micrograph of FIG. 6 for Example 3 with the electron micrograph of FIG. 7 for Comparative Example 3, in Example 3, minute (micron-order) irregularities were formed on the sheet surface. It can be confirmed that In the polypropylene-based resin foam laminated sheet of Example 3, it can be understood that the fine unevenness imparts good anti-slip properties and is matte to give a soft texture.

[Other Embodiments]
(1) In the above embodiment, the resin laminated sheet 1 is described as an example in which the thermoplastic resin layer 2 is provided with the polystyrene resin non-foamed layer 3 on one surface. However, the polystyrene resin non-foamed layer 3 may be provided on both surfaces of the thermoplastic resin layer 2 without being limited to such a configuration.

(2) In the above embodiment, the resin laminated sheet 1 has been described as an example in which the polypropylene resin non-foamed layer 4 is further provided in addition to the thermoplastic resin layer 2 and the polystyrene resin non-foamed layer 3. However, without being limited to such a configuration, for example, the resin laminated sheet 1 may not include the polypropylene resin non-foamed layer 4 but may include only the thermoplastic resin layer 2 and the polystyrene resin non-foamed layer 3. .

(3) The specific resin material of each layer, its composition, thickness, closed cell rate, cell diameter, cell number, etc. may be appropriately changed according to the required characteristics.

(4) In the above embodiment, the structure in which the thermoplastic resin layer 2, the polystyrene-based resin non-foaming layer 3 and the polypropylene-based resin non-foaming layer 4 are laminated by the co-extrusion method has been described as an example. However, the layers are not limited to such a configuration, and the layers may be laminated by another method such as an extrusion laminating method or a thermal laminating method.

(5) In the above embodiment, the resin laminated sheet 1 may further include a print film layer laminated on at least one surface. In this case, the printed film layer laminated on the polystyrene resin non-foamed layer 3 can be a printed polypropylene resin film or polystyrene resin film. The printed film layer laminated on the polypropylene resin non-foamed layer 4 may be a printed polypropylene resin film.

(6) The configuration disclosed in each of the above-described embodiments (including the above-described embodiment and other embodiments; the same applies hereinafter) is applied in combination with the configuration disclosed in other embodiments unless a contradiction occurs. It is also possible to do so. Regarding other configurations, the embodiments disclosed in the present specification are exemplifications in all respects, and can be appropriately modified within a range not departing from the spirit of the present disclosure.

1 Resin Laminate Sheet 2 Thermoplastic Resin Layer 3 Polystyrene Non-Foamed Layer 10 Container (Molded Product)

Claims (10)

A polypropylene resin foam layer, and a polystyrene resin non-foam layer laminated on at least one surface of the polypropylene resin foam layer ,
The constituent material of the polystyrene resin non-foamed layer contains 50 to 90% by weight of polystyrene resin and 50 to 10% by weight of polyolefin resin,
The static friction coefficient of the surface of the polystyrene resin non-foamed layer is 0.8 or more,
Arithmetic average roughness is 1.4 μm or more,
Ri der glossiness than 12%,
A resin laminated sheet having a density of 0.15 to 0.85 g / cm ³ .   The resin laminated sheet according to claim 1, wherein the constituent material of the polystyrene resin non-foamed layer further contains 0 to 10% by weight of a styrene thermoplastic elastomer. The resin laminated sheet according to claim 1 or 2, wherein the constituent material of the polypropylene resin foam layer includes a polypropylene resin having strain hardening properties. The resin laminated sheet according to claim 3, wherein the content of the strain-hardening polypropylene resin in the polypropylene resin foam layer is 60% by weight or more. Density is 0.25 to 0.35 g / cm ^Three The resin laminated sheet according to any one of claims 1 to 4. The resin laminated sheet according to any one of claims 1 to 5, wherein the polyolefin resin that constitutes the polystyrene resin non-foamed layer is a polypropylene resin. The resin laminated sheet according to any one of claims 1 to 6, wherein the polypropylene-based resin foam layer has 10 to 30 bubbles per 1 mm in thickness. 8. The polypropylene-based resin non-foamed layer is laminated on one surface of the polypropylene-based resin foamed layer, and the polypropylene-based resin non-foamed layer is laminated on the other surface. The resin laminated sheet according to [4]. The resin laminate sheet according to any one of claims 1 to 7, a molded article wherein the polystyrene resin non-foamed layer is formed by thermoforming so that the outermost layer. A molded article obtained by thermoforming the resin laminated sheet according to claim 8 so that the polypropylene resin non-foamed layer is the innermost layer and the polystyrene resin non-foamed layer is the outermost layer.