WO2021182461A1

WO2021182461A1 - Laminate

Info

Publication number: WO2021182461A1
Application number: PCT/JP2021/009254
Authority: WO
Inventors: 後藤　敏晴; 水谷　圭
Original assignee: マクセルホールディングス株式会社
Priority date: 2020-03-13
Filing date: 2021-03-09
Publication date: 2021-09-16
Also published as: JP2023046419A

Abstract

Provided is a laminate in which when a crack occurs on the surface, the crack is easier to find at an early stage. The laminate (tread 11) is provided with an inner layer 12 that is made of a molded resin, and an outer layer 13 that is laminated on the outside of the inner layer 12 and that is made of reinforced fiber. The inner layer 12 has a first color on the surface on which the outer layer 13 is laminated. The outer layer 13 has a second color on the outside surface. The color difference between the first color of the inner layer 12 and the second color of the outer layer 13 is at least 40 in the CIELAb color space. When a crack occurs in the outer layer 13, the color difference makes it easier to see the crack. As a result, it becomes possible to repair or replace the cracked tread 11 at an early stage.

Description

Laminate

This disclosure relates to a laminate containing scaffolding materials used at construction sites.

The scaffolding material is made of metal such as iron and aluminum. Metal scaffolding is relatively heavy. Therefore, the metal scaffolding material increases the cost burden for transportation, installation, removal, etc., and the physical burden on the user. Hereinafter, scaffolding materials for the purpose of weight reduction are provided.

Japanese Unexamined Patent Publication No. 2018-141276 discloses a lightweight and high-strength scaffolding board panel. The scaffolding board panel includes two fiber-reinforced resin sheets and a hollow structure portion made of a polyolefin resin. The hollow structure portion is arranged between the two fiber-reinforced resin sheets, and a plurality of hollow portions separated by a vertical wall are formed at intervals, for example, like a honeycomb structure.

Japanese Unexamined Patent Publication No. 2018-141276

However, although the strength of the scaffolding board panel is improved by arranging the fiber reinforced resin sheets on the main surfaces on both sides of the hollow structure, there may be a problem in strength as compared with the metal scaffolding material. .. That is, the surface of the scaffolding board panel is more likely to be cracked due to the traffic of users and deterioration over time than the metal scaffolding material. Such cracks in the resin product and the resin member are not limited to the scaffolding material, and may occur in various resin products and the resin member.

Therefore, it is an object of the present disclosure to provide a laminate that facilitates early detection of cracks even if cracks occur on the surface.

In order to solve the above problems, this disclosure has taken the following solutions. That is, the laminate according to the present disclosure may include an inner layer which is a molding resin and an outer layer which is laminated on the outside of the inner layer and is a reinforcing fiber. The inner layer may have a first color on the surface on which the outer layers are laminated. The outer layer may have a second color on the outer surface. The color difference between the first color of the inner layer and the second color of the outer layer may be 40 or more in the CIELab color space.

According to the laminate according to the present disclosure, even if cracks occur on the surface, it is possible to easily detect the cracks at an early stage.

FIG. 1 is an external perspective view showing the structure of the tread plate of the scaffolding material according to the embodiment. FIG. 2 is an enlarged cross-sectional view taken along the line AA'of the tread plate shown in FIG. FIG. 3 is an external perspective view showing the structure of the support columns of the scaffolding material according to the embodiment. FIG. 4 is an enlarged cross-sectional view taken along the line BB'shown in FIG.

The laminate may include an inner layer that is a molding resin and an outer layer that is laminated on the outside of the inner layer and is a reinforcing fiber. The inner layer may have a first color on the surface on which the outer layers are laminated. The outer layer may have a second color on the outer surface. The color difference between the first color of the inner layer and the second color of the outer layer may be 40 or more in the CIELab color space.

As a result, when a crack occurs in the outer layer, the crack in the laminated body can be visually recognized by the color difference between the second color of the inner layer and the second color of the outer layer, and the crack can be easily detected at an early stage.

The molding resin may be a foamed resin. As a result, the weight of the laminated body can be reduced.

The foamed resin may be a foamed polycarbonate resin. Polycarbonate resin has relatively high strength. Therefore, cracks are unlikely to occur in the inner layer, and cracks can easily occur only in the outer layer. When cracks occur only in the outer layer without cracks in the inner layer, the cracks in the outer layer, that is, the cracks in the laminated body can be visually recognized by the color difference between the first color of the inner layer and the second color of the outer layer, and the cracks can be detected early. It can be done easily. Further, since cracks are unlikely to occur in the inner layer, the cracks can be visually recognized by arranging the first color only on the surface of the inner layer.

The reinforcing fiber may be a fiber reinforced resin reinforced by containing a resin.

The fiber reinforced resin may contain carbon fiber.

The outer layer may have a thickness of 1 mm or less. By making the thickness of the outer layer relatively thin, it is possible that cracks are less likely to occur in the inner layer and cracks are likely to occur only in the outer layer. When cracks occur only in the outer layer without cracks in the inner layer, the cracks in the outer layer, that is, the cracks in the laminated body can be visually recognized by the color difference between the first color of the inner layer and the second color of the outer layer, and the cracks can be detected early. It can be done easily. Further, since cracks are unlikely to occur in the inner layer, the cracks can be visually recognized by arranging the first color only on the surface of the inner layer.

The laminated body may be a tread plate. This makes it easier to detect cracks in the tread at an early stage.

The laminated body may be a support member for supporting the tread plate. This makes it easier to detect cracks in the support member at an early stage.

Hereinafter, embodiments of the laminated body of the present disclosure will be specifically described with reference to FIGS. 1 to 4. Here, a scaffolding material used at a building construction site or the like as a laminated body will be described. However, the laminate is not limited to scaffolding materials, and resin products and resin members that require the detection of cracks in ladders, stepladders, foldable scaffolding, and parts of floors of automobiles, trains, buses, etc. Is included. From the viewpoint of suppressing the destruction of the laminated body due to the occurrence of cracks, the laminated body is particularly used as a tread plate for a person to put on, such as a scaffolding material or a floor material, and a support member for supporting the tread plate. It is preferably used. That is, in the present specification, the tread plate means not only a tread plate for scaffolding but also a plate material on which a person's foot is pressed from above when walking or the like. The support member includes a support column or the like that supports the tread plate.

(Embodiment 1)
First, as the first embodiment, the tread plate 11 (laminated body) of the scaffolding material will be specifically described with reference to FIGS. As shown in FIGS. 1 and 2, the tread plate 11 includes an inner layer 12 and an outer layer 13 laminated on the outer side of the inner layer 12.

The inner layer 12 is a plate-shaped molding resin. The inner layer 12 has at least a color on its surface. The color of the inner layer 12 has a color difference from the color of the outer layer 13. The color difference between the color of the inner layer 12 and the color of the outer layer 13 will be described later. The color of the inner layer 12 may be the color of the molding resin material itself. For example, when the inner layer 12 is a foamed polycarbonate resin, the color of the inner layer 12 is close to white. Further, the color of the inner layer 12 may be resin-molded after coloring the molten resin material in advance. In that case, the inner layer 12 may have a color not only on the surface but also on the solid portion. Further, the color of the inner layer 12 may be colored on the surface of the inner layer 12 after resin molding.

The inner layer 12 can be a plate-shaped foamed resin containing 50% by weight or more of a polycarbonate resin. The resin contained in the inner layer 12 may contain 100% by weight of the polycarbonate resin, a compound resin of the polycarbonate resin and at least one of the other resin and the inert particles, or a copolymerized polycarbonate resin. Other resins include ABS resin, AS resin, acrylic resin, polyester resin (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycyclohexanedimethylene terephthalate, polybutylene naphthalate, etc.), PPS resin, polyphenylene ether resin, polyether. Sulfone resin, polysulfone resin, polypropylene resin, polyethylene resin, polystyrene resin, fluororesin (for example, polytetrafluoroethylene), polyamide resin, polyimide resin, cycloolefin resin, ethylenetetrafluoroethylene resin, polyvinylidene fluoride resin, polylactide resin , Polybutylene succinate resin, polybutylene succinate adipate resin, polycabrolactone resin, hydroxybutyric acid-hydroxyhexanoic acid copolymer and the like. The other resins may be used alone or in combination of two or more. From the viewpoint of improving the strength of the inner layer 12, the polycarbonate resin is preferably 50% by weight or more, preferably 60% by weight or more, and more preferably 70% by weight or more. The inert particles are talc, clay, silica, glass fiber, carbon fiber, cellulose, calcium carbonate, titanium oxide and the like. The inert particles may be used alone or in combination of two or more. From the viewpoint of weight reduction, the inert particles are preferably 40% by weight or less, preferably 30% by weight or less, and more preferably 20% by weight or less.

On the other hand, since the polycarbonate resin has a high melt viscosity and low fluidity, it is difficult for the physical foaming agent to be mixed and it is difficult to secure a high foaming ratio of the foamed molded product. Further, when the polycarbonate resin is physically foamed, it is plasticized only by adding a foaming agent, so that the melt viscosity tends to decrease, but the viscosity increases when the cooling step after the foaming treatment is started. Therefore, as will be described later, when the polycarbonate resin is extruded from the die of the extruder for molding, air bubbles near the surface of the inner layer 12 may be broken and the surface may be roughened. As described above, the polycarbonate resin may have a problem in moldability. To solve such problems, a polycarbonate resin having a low viscosity average molecular weight (including a resin obtained by blending a polycarbonate resin having a high viscosity average molecular weight with a polycarbonate resin having a low viscosity average molecular weight) is used, or a resin having good fluidity is used. Alternatively, it is conceivable to add an additive such as a filler to secure the fluidity. However, if a polycarbonate resin having an excessively low viscosity average molecular weight is used, the strength of the inner layer 12 may decrease. Therefore, in view of maintaining both the strength and moldability of the inner layer 12 in a well-balanced manner, it is preferable to alloy other resins whose fluidity is improved by mixing with the polycarbonate resin. From such a viewpoint, the polycarbonate resin is preferably 90% by weight or less, more preferably 80% by weight or less. The other resin having good fluidity is at least one selected from the group consisting of polyester resin (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), ABS resin, AS resin, polypropylene resin, and acrylic resin. Two resins can be mentioned. From the viewpoint of improving the strength, the content of the polycarbonate resin contained in the inner layer 12 is preferably 100% by weight.

The polycarbonate resin is not particularly limited as long as it has a carbonate bond in the main chain, and examples thereof include aromatic polycarbonate, aliphatic polycarbonate, and aromatic-aliphatic polycarbonate. The polycarbonate resin can be obtained, for example, by a method of transesterifying a dihydroxy compound and a carbonic acid diester, or a method of intercondensing the dihydroxy compound and phosgene in the presence of an alkaline catalyst. The dihydroxy compound may be a compound having two hydroxy groups in the molecule, and may be bisphenol A, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, or 2,2-bis (4-). Hydroxyphenyl-3-methylphenyl) propane, 2,2-bis (3-tert-butyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis ( Aromatic dihydroxy compounds such as 4-hydroxyphenyl) methane, 1,1-bis (p-hydroxyphenyl) ethane, 2,2-bis (p-hydroxyphenyl) butane; ethylene glycol, 1,2-propylene glycol, 3 Examples thereof include aliphatic dihydroxy compounds such as -methyl-1,5-pentanediol, 1,6-hexanediol, 1,3-propanediol, and 1,4-butanediol. These dihydroxy compounds may be used alone or in combination of two or more. In addition to the dihydroxy compound, the polycarbonate resin may contain a structural unit derived from a monohydroxy compound, a trihydroxy compound, or the like.

For example, when the inner layer 12 is formed by including a polycarbonate resin and a polypropylene resin, the polypropylene resin can improve the foaming characteristics of the polycarbonate resin, that is, improve the fluidity and increase the foaming ratio, so that the tread plate can be formed. The weight of 11 can be reduced. Further, even when the inner layer 12 is formed by including the polycarbonate resin and the ABS resin, the foaming ratio can be increased as in the case where the polypropylene resin is contained, so that the tread plate 11 can be reduced in weight. .. On the other hand, when the inner layer 12 is formed by including the polycarbonate resin and the polyester resin, the tread plate 11 can maintain the strength because the polyester resin has the same strength as the polycarbonate resin. As described above, the tread plate 11 can determine the resin to be combined with the polycarbonate resin depending on whether the weight reduction or the strength is emphasized. Even when the weight is reduced, the inner layer 12 contains 50% by weight or more of the polycarbonate resin, and therefore has sufficient strength.

Further, the inner layer 12 has a foaming ratio of 1.2 to 4 times. When the foaming ratio is low, the strength of the inner layer 12 is high, but the effects of heat resistance and weight reduction are lowered. On the other hand, when the foaming ratio is high, the strength of the inner layer 12 is reduced, but the heat resistance and lightness are improved. Therefore, in consideration of the balance between the strength, heat resistance and light weight of the tread plate 11, the foaming ratio is preferably 1.2 times or more, preferably 1.5 times or more, more preferably 2 times or more, and 4 times. Hereinafter, it is preferably 3.5 times or less, and more preferably 3 times or less. The inner layer 12 is foam-molded by adding a foaming agent to a molten resin material obtained by melting a resin as a raw material and passing it through a die of an extruder.

The inner layer 12 is foam-molded with at least one of a chemical foaming agent and a physical foaming agent. The physical foaming agent is, for example, carbon dioxide, nitrogen, air, argon, helium and the like. The chemical foaming agent is, for example, zinc carbonate, baking soda, azodicarbonamide and the like. Since the inner layer 12 is foam-molded using a chemical foaming agent, the foaming ratio tends to be high, so that the specific gravity of the tread plate 11 can be further reduced. However, when a chemical foaming agent is used, by-products such as water and ammonia are also generated, the viscosity average molecular weight is lowered, and the strength of the tread plate 11 is lowered. Therefore, in foam molding with a chemical foaming agent, the viscosity average molecular weight of the polycarbonate resin is preferably 30,000 or more. Further, since the inner layer 12 is foam-molded using a physical foaming agent, not only a clean product can be obtained without polluting the environment, but also air, nitrogen, and carbon dioxide gas use atmospheric gas. It is also advantageous in terms of cost. Further, when the inner layer 12 is foam-molded by using the chemical foaming agent and the physical foaming agent in combination, the chemical foaming agent is less than 1% by weight based on the total weight (total weight) of the resin and the additive used for the foam molding. It is better to do it. By foaming and molding with less chemical foaming agent than physical foaming agent in this way, the risk of a decrease in strength due to hydrolysis can be reduced, the environment is less likely to be polluted, and costs can be reduced. can. That is, it is possible to balance cost, strength and weight reduction.

The viscosity average molecular weight of the polycarbonate resin is 10,000 to 100,000. If the viscosity average molecular weight of the resin contained in the inner layer 12 is too high, the viscosity increases, the torque required for the extruder during extrusion molding increases, and extrusion processing becomes difficult. As a result, if the molecular weight of the resin is increased, the strength of the molded product after processing can be improved, but the production itself is hindered. On the other hand, if the viscosity average molecular weight of the polycarbonate resin is too low, the bubbles tend to coalesce and the bubble diameter does not become uniform, so that the strength after curing decreases. In addition, the decrease in melt tension makes it difficult to foam. Therefore, the viscosity average molecular weight of the polycarbonate resin is preferably 10,000 or more, preferably 15,000 or more, and preferably 100,000 or less, preferably 50,000 or less. That is, by setting the viscosity average molecular weight of the polycarbonate resin to 10,000 to 100,000, it is possible to obtain the effects of improving the strength and reducing the weight of the tread plate 11 while facilitating molding.

The viscosity average molecular weight of the polycarbonate resin may be obtained by mixing a resin having a viscosity average molecular weight of less than 15,000 or more than 50,000. For example, an aromatic polycarbonate resin having a viscosity average molecular weight of more than 50,000 improves the entropy elasticity of the resin, and thus exhibits good molding processability in foam molding of the inner layer 12. Such improvement in molding processability is even better than that of branched polycarbonate. In a more preferred embodiment, the viscosity average molecular weight of the polycarbonate is composed of an aromatic polycarbonate resin having a viscosity average molecular weight of 70,000 to 300,000 and an aromatic polycarbonate resin having a viscosity average molecular weight of 10,000 to 30,000, and these are mixed or blended without mixing. Aromatic polycarbonate resins of 16000 to 35000 can also be used. When the content of the other resin contained together with the polycarbonate resin is 30 to 50% by weight with respect to the inner layer 12, it is preferable to use a polycarbonate resin having a relatively high viscosity average molecular weight of 25,000 or more.

The viscosity average molecular weight in the present disclosure is calculated as follows. _{First, using an Ostwald viscometer, the specific viscosity (η SP} ) is calculated from a solution of 0.7 g of aromatic polycarbonate in 100 ml of methylene chloride at 20 ° C. The specific viscosity can be calculated by the formula {(t-t ₀ ) / t _0}. t ₀ is the number of seconds for the methylene chloride (solvent) to fall, and t is the falling speed of the sample solution. Using the calculated specific viscosity, the viscosity average molecular weight M is calculated by the formula _{{η SP} / c = [η] + 0.45 × [ ^{η] 2 c}.} [Η] in the formula is the ultimate viscosity {[η] = 1.23 × 10 ^-4 M ^0.83 }. Further, c in the formula is the concentration of aromatic polycarbonate (0.7%).

The outer layer 13 is a reinforcing fiber. The reinforcing fiber is a sheet-shaped fiber reinforced resin reinforced by containing a resin, that is, a fiber reinforced resin sheet containing fibers. The outer layer 13 has at least a color on its surface. As described above, the color of the outer layer 13 has a color difference from the color of the inner layer 12. The color difference between the color of the inner layer 12 and the color of the outer layer 13 is 40 or more in the CIELab color space. The details of the color difference will be described later. The color of the outer layer 13 may be the color of the material itself of the fiber reinforced resin sheet. For example, when the outer layer 13 is a carbon fiber reinforced resin, the color of the outer layer 13 is close to black. Further, the color of the outer layer 13 may be colored on the outer surface of the outer layer 13. The exterior 13 is not made of a fiber reinforced resin sheet, but is at least one selected from a group of woven fabrics such as plain weave, twill weave and double weave, those which are aligned vertically, horizontally and diagonally and hardened, and non-woven fabrics. May be good. In the reinforcing fiber, the composite material contained together with the fiber is not limited to the resin, and other materials may be used.

Normally, the color difference in the CIELab color space is shown in the range of 0 to 100. The color difference between the color of the inner layer 12 and the color of the outer layer 13 is preferably 40 or more, more preferably 70 or more, and more preferably 90 or more. As a result, when a crack is generated in the outer layer 13, the crack in the tread plate 11 can be easily visually recognized due to the color difference between the color of the outer layer 13 and the color of the inner layer 12. As a result, cracks in the laminated body (tread plate 11) can be easily detected at an early stage. Then, the user can repair the crack in the tread plate 11 or replace the tread plate 11 with a new one.

The outer layer 13 is formed in a shape substantially similar to the shape of the main surface of the inner layer 12. The outer layer 13 is laminated on the main surfaces on both sides of the inner layer 12. That is, as shown in FIG. 1, the inner layer 12 is arranged between one outer layer 13 and the other outer layer 13. As a result, the tread plate 11 can improve the bending strength against the stress applied from the vertical direction to the main surface of the tread plate 11. That is, the outer layer 13 functions as a reinforcing material for the inner layer 12. In addition, one outer layer 13 may be laminated on the main surface of one side of the inner layer 12.

The resin contained in the outer layer 13 is a polyester resin, an epoxy resin, an acrylic resin, a polycarbonate resin, a polyether sulfone resin, a polyamide resin, a polyethylene resin, a polypropylene resin, a polylactic acid resin, a phenol resin, a polybutylene succinate resin, or the like. .. The resin contained in the outer layer 13 is not limited to these, and other resin materials may be used.

The fibers contained in the outer layer 13 are carbon fibers, glass fibers, aramid fibers, polyester fibers, acrylic fibers, polyethylene fibers, polypropylene fibers, hollow metal fibers and the like. Hollow metal fibers are stainless steel, steel and the like. The fibers contained in the outer layer 13 are not limited to these, and other fiber materials may be used.

The basis weight of the fibers contained in the outer layer 13 is 100 to 500 g / m ² . The fiber contained in the outer layer 13 is at least one selected from the group of woven fabrics such as plain weave, twill weave and double weave, those which are aligned vertically, horizontally and diagonally and hardened, and non-woven fabrics, or those obtained by superimposing these. be. The fiber contained in the outer layer 13 is preferably a woven fabric that is sufficiently supplied in the market and easy to handle. If the basis weight of the fibers is too low, the tread plate 11 is insufficiently reinforced by the outer layer 13, and as a result, it becomes difficult to secure the strength. On the other hand, if the basis weight of the fibers is too high, the weight of the tread plate 11 becomes relatively large, and it becomes difficult to reduce the weight. Further, in the case of a cloth heavier than 500 g / m ² , it becomes difficult to cut and the rigidity of the cloth becomes too high, which may reduce the workability when laminating. As described above, the basis weight of the fibers contained in the outer layer 13 is more preferably 100 g / m ² or more, preferably 175 g / m ² or more, more preferably 250 g / m, from the viewpoint of balancing the improvement of strength and the weight reduction. m ² or more to the good, 500 g / ^{m 2} or less, preferably 425 g / ^{m 2} or less, and more preferably from a 350 g / ^{m 2} or less.

The thickness of the outer layer 13 is 1 mm or less. By making the thickness of the outer layer 13 relatively thin in this way, the tread plate 11 can cause the outer layer 13 to crack before the inner layer 12 cracks. That is, since the inner layer 12 is not cracked when the outer layer 13 is cracked, the tread plate 11 makes it easier to visually recognize the crevice (crack in the tread plate 11) of the outer layer 13 due to the color difference between the inner layer 12 and the outer layer 13. .. Further, since cracks do not occur in the inner layer 12, at least the surface of the inner layer 12 may be provided with a color having a color difference from the color of the outer layer 13. However, if the thickness of the outer layer 13 is made too thin, the bending strength of the tread plate 11 may decrease. Therefore, the thickness of the outer layer 13 is preferably 0.1 mm or more, preferably 0.2 mm or more, more preferably 0.3 mm or more, and 1.5 mm or less, preferably 0.9 mm or less, more preferably 0. It is preferably 8 mm or less.

Next, the color difference will be explained in detail. The color difference in the present specification refers to a value measured using a commercially available color difference meter (CR-400 manufactured by Konica Minolta Co., Ltd.). When the above-mentioned color difference meter is used, it is possible to obtain the color difference from the color of the other material based on the color of one of the two materials. When the outer layer 13 is adhered to the surface of the inner layer 12, the outer layer 13 and the adhesive layer adhering the inner layer 12 and the outer layer 13 are completely removed by grinding, and if necessary, dust or the like attached to the surface is removed. And measure the color of the inner layer 12.

As described above, since the tread plate 11 (laminated body) has a color difference of 40 or more between the inner layer 12 and the outer layer 13, even if a crack occurs in the tread plate 11, the user can use the tread plate 11 at an early stage. It becomes easier to find cracks. When a crack occurs in the tread plate 11, the user can repair the crack in the tread plate 11 or replace the tread plate 11 with a new one.

As described above, the inner layer 12 contains 50% by weight or more of the polycarbonate resin. Polycarbonate resin has relatively high strength. Therefore, the inner layer 12 is less likely to be cracked, and only the outer layer 13 can be easily cracked. That is, in the tread plate 11, when the outer layer 13 is cracked, the inner layer 12 is not cracked. It becomes easier to see. Further, since cracks are unlikely to occur in the inner layer 12, at least the surface of the inner layer 12 may be provided with a color having a color difference from the color of the outer layer 13.

When a load is applied, the polycarbonate resin is plastically deformed by yielding and then fractured, but the amount of plastic deformation from yielding to fracture is large. Therefore, the polycarbonate resin does not break immediately after yielding and has a tenacious property. As a result, the outer layer 13 can be cracked before the inner layer 12 is deformed and cracks are generated. Further, since the polycarbonate resin has a tenacious property, it is possible to take measures such as replacing the tread plate 11 with a margin.

Further, the inner layer 12 contains 50% by weight or more of the polycarbonate resin, so that the sea-island structure is formed by the polycarbonate resin and the resin contained together with the polycarbonate resin. That is, the inner layer 12 has a sea-island structure in which the polycarbonate resin is a sea component and the resin contained together with the polycarbonate resin is an island component.

At that time, the outer layer 13 is filled with the resin contained in the outer layer 13 (a compound resin of the polycarbonate resin and at least one of the other resin and the inert particles, a copolymerized polycarbonate resin, or a polycarbonate resin blended with other resins). 50% by weight or more of the polycarbonate resin may be included. In this case, the resin contained in the outer layer 13 is the same as the resin contained in the inner layer 12 described above, and thus the description thereof will be omitted. By including 50% by weight or more of the polycarbonate resin in the outer layer 13, a sea-island structure in which the polycarbonate resin is a sea component and the resin contained together with the polycarbonate resin is an island component is formed as in the inner layer 12.

As described above, by containing 50% by weight or more of the polycarbonate resin in each of the inner layer 12 and the outer layer 13, a sea-island structure is formed in which the polycarbonate resin is a sea component and the resin contained together with the polycarbonate resin is an island component. That is, the resin contained together with the polycarbonate resin is formed inside the inner layer 12 and the outer layer 13 as an island component, and a large amount of the polycarbonate resin of the sea component is exposed on the surface of the main surface of the inner layer 12 and the outer layer 13. .. As a result, when the outer layer 13 is bonded to the main surface of the inner layer 12, the adhesiveness between the inner layer 12 and the outer layer 13 can be improved due to the compatibility between the polycarbonate resins. As a result, the peeling of the outer layer 13 from the inner layer 12 can be suppressed, and the strength of the tread plate 11 can be further improved.

The color of the inner layer 12 and the color of the outer layer 13 may be a single color or a combination of a plurality of colors. In particular, the color of the inner layer 12 can be a color that generally indicates danger, such as a reddish color or a yellowish color. As a result, the occurrence of cracks can be clearly shown to the user. Further, the color of the inner layer 12 may be a combination of a plurality of colors such as a rainbow-colored pattern and a yellow and black striped pattern. At this time, if the color of the outer layer 13 is a single color, a difference in visual characteristics occurs between the color of the inner layer 12 and the color of the outer layer 13, and the visibility of cracks can be improved. On the other hand, the color of the outer layer 13 may be a combination of a plurality of colors in the same manner as the color of the inner layer 12, but when a crack occurs in the outer layer 13, the color of the inner layer 12 is emphasized and the crack is visually recognized. Considering the ease of use, it is better to use a single color. When the color of the inner layer 12 and the color of the outer layer 13 are compound colors, the color difference is measured by the above-mentioned color difference meter in each of the color combinations of the inner layer 12 and the outer layer 13, and the average value of each color difference is taken as the inner layer. The color difference between the color of 12 and the color of the outer layer 13.

Further, the color of the inner layer 12 is darker than the color of the outer layer 13, that is, the lightness can be made lower in the CIELab color space. As a result, when the bottom side of the crack of the tread plate 11, that is, the inner layer 12 side of the crack becomes a shadow, the contrast with the color of the outer layer 13 which is brighter than the color of the inner layer 12 increases, and the crack of the tread plate 11 (laminate) is formed. It can be made easier to see.

Further, the color of the inner layer 12 may be present not only on the surface but also on the solid part. In this case, the color difference between the color of the solid portion of the inner layer 12 and the color of the outer layer 13 is 40 or more. As a result, even if cracks occur not only in the outer layer 13 but also in the inner layer 12, the cracks in the tread plate 11 (laminated body) due to the color difference between the color of the solid portion of the inner layer 12 and the color of the surface of the outer layer 13. Can be easily seen.

Further, when the tread plate 11 is used as the laminated body, a plurality of tread plates 11 may be arranged side by side in the width direction. For example, although not particularly shown, a quadrangular frame arranged in the horizontal direction may be provided. Each of the four corners of the frame is fixed by a support. The plurality of treads 11 can be arranged side by side in the width direction by supporting both ends of each tread 11 in the length direction on a square frame in the shape of a drainboard. As a result, even if a part of the treads 11 is cracked or a part of the treads 11 is destroyed, the user can be supported by the treads 11 on both sides of the part of the treads 11. ..

According to the laminate in the present disclosure, even for resin products and resin members that require the detection of cracks such as ladders, stepladders, foldable scaffolds, and parts of floors of automobiles, trains, buses, etc., at an early stage. You can easily find cracks. As a result, such resin products and resin members can be repaired, replaced, or discarded at an early stage.

(Manufacturing method of tread plate 11)
Next, a method for manufacturing the tread plate 11 (laminated body) will be specifically described.

First, the manufacturing method of the inner layer 12 will be described.

The inner layer 12 of the tread plate 11 is molded by a deformed extrusion molding method. Specifically, first, in an extruder such as a screw, the pellets of polycarbonate resin and other resins, for example, pellets of polypropylene resin, inert particles, etc. are heated and melted, and the polycarbonate resin is 50% by weight or more. The molten resin material is produced by mixing so as to be. The blending ratio of 50% by weight or more of the polycarbonate resin (pellets) is a ratio to the weight including other resins (pellets) and inert particles charged into the extruder. Further, in the extruder, at least one of the chemical foaming agent and the physical foaming agent is injected into the produced molten resin material, and the molten resin material and the foaming agent are mixed. When coloring the solid portion of the inner layer 12, a coloring agent such as a paint is added at any timing before or after injecting the foaming agent, and the inner layer 12 is kneaded with the molten resin material.

Next, the molten resin material mixed with the foaming agent is poured into a die, and the inner layer 12 is formed while gradually lowering the temperature by passing the die. The die is open in the direction of extruding the molten resin material. At the same time, bubbles are generated in the molten resin material mixed with the foaming agent due to the pressure drop when passing through the die. As a result, the inner layer 12 is foam-molded.

At this time, the outer layer 13 can be attached to the main surface of the inner layer 12. That is, the outer layer 13 is attached to the main surface of the inner layer 12 before being cured by cooling without using an adhesive. As described above, the outer layer 13 is formed by impregnating the resin with a fiber material woven by plain weave or the like. The method for producing the outer layer 13 is not particularly limited. When coloring only the main surface of the inner layer 12, a coloring agent such as a paint is applied to the main surface of the inner layer 12 after molding the inner layer 12, and then the outer layer 13 is bonded. When the surface of the outer layer 13 is colored, a coloring agent such as a paint is applied to the surface of the outer layer 13 before the outer layer 13 is attached to the main surface of the inner layer 12. When the inner layer 12 and the outer layer 13 are not colored, the coloring step can be omitted.

Next, shape the inner layer 12 and the outer layer 13 while cooling them in the cooling tank. In this state, the inner layer 12 and the outer layer 13 are formed in a continuous plate shape. Therefore, these are cut to a predetermined size. In this way, the tread plate 11 is manufactured.

The method of molding the inner layer 12 is not limited to the deformed extrusion molding method, and may be another molding method such as injection molding. Further, the method of foam molding the inner layer 12 may be appropriately changed according to the molding method of the inner layer 12. In the method of laminating the outer layer 13 on the main surface of the inner layer 12, after the inner layer 12 is cooled in a cooling tank, a solvent capable of dissolving the polycarbonate resin is applied to the surface of either the inner layer 12 or the outer layer 13 or facing each other. An appropriate amount may be applied to both surfaces, and the two may be bonded together and then dried. Further, the outer layer 13 may be attached after the inner layer 12 is shaped and cut.

(Embodiment 2)
Next, as the second embodiment, the case where the laminated body is the support column 21 of the scaffolding material will be described. The support column 21 is a support member for supporting the tread plate 11. As shown in FIGS. 3 and 4, the support column 21 includes an inner layer 22 and an outer layer 23 laminated on the outer side of the inner layer 22.

The inner layer 22 is a cylinder. Since the material of the inner layer 22 is the same as that of the inner layer 12 of the tread plate 11, the description thereof will be omitted.

The outer layer 23 is laminated on the outer peripheral surface of the inner layer 22. Since the material of the outer layer 23 is the same as that of the outer layer 13 of the tread plate 11, the description thereof will be omitted. Further, since the thickness of the outer layer 23 is the same as the thickness of the outer layer 13 of the tread plate 11, the description thereof will be omitted.

The support column 21 may crack due to heavy wind and rain. According to the support column 21, even if a crack occurs on the surface like the tread plate 11, the crack is easily visible. Therefore, the user can repair the crack of the support column 21 at an early stage, or replace the support column 21 with a new one.

Also in the case of the support column 21, the color difference between the color of the inner layer 22 and the color of the outer layer 23 is measured using a color difference meter (Konica Minolta Co., Ltd. CR-400) as described above.

Next, a method of manufacturing the support column 21 of the second embodiment will be described.

The basic process of manufacturing the support column 21 is the same as that of the tread plate 11 described above. The difference from the tread plate 11 in the method of manufacturing the support column 21 is that the shape extruded from the die is plate-shaped in the tread plate 11, whereas it is cylindrical in the support column 21. Then, in the case of the support column 21, the outer layer 23 is attached to the outer peripheral surface of the inner layer 22.

As described above, the laminated body can be used by forming it not only in a plate-like body such as a tread plate 11 but also in a cylindrical body such as a support column 21. That is, the shape of the laminated body is not particularly limited. The support member is not limited to the support member 21 of the scaffolding material. For example, when the tread plate 11 is a floor material, aluminum, iron, wooden columns, or the like may be used as the support member.

Although the embodiments have been described above, the present disclosure is not limited to the above embodiments, and various changes can be made as long as the purpose is not deviated.

(Example)
As shown in Table 1 below, the scaffolding materials of Examples 1 to 4 and the scaffolding materials of Comparative Examples 1 to 4 were prepared, and in each scaffolding material, the color of the inner layer, the color and the color difference of the outer layer were calculated, and cracks were formed. Visibility test was conducted. The widths of the treads of Examples 1 and 2 and the treads of Comparative Examples 1 and 2 are 400 mm, respectively, and the length is 1800 mm. Further, the columns of Examples 3 and 4 and the columns of Comparative Examples 3 and 4 have a cylindrical shape, respectively. The diameter of each strut is 50 mm and the length is 1800 mm. In Table 1, PC indicates a polycarbonate resin, CFPR indicates a carbon fiber reinforced resin, and GFRP indicates a glass fiber reinforced resin. The PCs (including carbon) of Examples 2 and 4 use polycarbonate containing 1% carbon black. The PC (white) of Comparative Examples 2 and 4 indicates an outer layer formed by mixing a white colorant with a polycarbonate resin.

For the color difference, except for Comparative Example 2 and Comparative Example 4, the color difference between the color of the material of the inner layer and the color of the material of the outer layer was calculated. For example, in Example 1, the inner layer is foamed PC and the outer layer is epoxy-cured CFRP. The color of the foamed PC is usually close to white, and the color of the epoxy-cured CFRP is usually close to black. The color difference between the inner layer and the outer layer of Example 1 was measured using a color difference meter (CR-400 manufactured by Konica Minolta Co., Ltd.) as described above.

The visibility test was carried out by setting each scaffolding material as the distance between fulcrums in the length direction and 1 m, pressurizing the center of the distance between fulcrums, and applying strain until at least a part of the outer layer was cracked. The visibility of the crack was confirmed by the following method. That is, in Example 1, 20 people who have experience in scaffolding assembly work looked at the 20 scaffolding materials arranged side by side and confirmed whether or not one scaffolding material with a crack could be selected within 10 seconds. .. One scaffolding material with cracks was arranged side by side so that the cracks could be seen on the outside. The visibility evaluation of cracks was evaluated as "A" when 15 or more people could be selected, and "B" in other cases. The results are shown in Table 1 below.

As shown in Table 1, cracks were immediately confirmed in the scaffolding materials of Examples 1 to 4 by 15 or more people who had experience in scaffolding assembly work out of 20 people. That is, a person who has experience in scaffolding assembly work was able to sufficiently recognize cracks when the color difference between the color of the inner layer and the color of the outer layer was 100 and 70, which were relatively large.

On the other hand, in the scaffolding materials of Comparative Examples 1 to 4, no cracks were confirmed by 15 or more scaffolding assembly workers out of 20 people, and the number of scaffolding assembly workers who could see the cracks was relatively small. That is, a person who has experience in scaffolding assembly work could not sufficiently visually recognize the cracks when the color difference between the color of the inner layer and the color of the outer layer was 15 and 20, which were relatively small.

As described above, when the color difference was 100 and 70, the crack could be sufficiently visually recognized, and when the color difference was 15 and 20, the crack could not be sufficiently visually recognized. Inferring from this result, it is considered that the cracks can be visually recognized if the color difference is at least 40 or more. If the user cannot see the cracks, the cracks generated in the scaffolding material are left unattended, and the neglected cracks cause the scaffolding material to be destroyed. As a result, cracks may be left in the scaffolding materials of Comparative Examples 1 to 4. On the other hand, if the color difference between the color of the inner layer and the color of the outer layer is at least 40 or more, the cracks generated in the scaffolding material can be easily visually recognized by the user. As a result, the scaffolding material can be repaired or replaced before the scaffolding material is destroyed due to the cracks.

11 treads, 12 inner layers, 13 outer layers, 21 columns, 22 inner layers, 23 outer layers

Claims

An inner layer that is a molding resin and an outer layer that is laminated on the outside of the inner layer and is a reinforcing fiber are provided.
The inner layer has a first color on the surface on which the outer layer is laminated.
The outer layer has a second color on the outer surface and
A laminate in which the color difference between the first color of the inner layer and the second color of the outer layer is 40 or more in the CIELab color space.
The laminated body according to claim 1.
The molding resin is a laminated body which is a foamed resin.
The laminated body according to claim 1 or 2.
The foamed resin is a laminated body which is a foamed polycarbonate resin.
The laminated body according to any one of claims 1 to 3.
The reinforcing fiber is a laminated body which is a fiber reinforced resin reinforced by containing a resin.
The laminated body according to claim 4.
The fiber reinforced resin is a laminate containing carbon fibers.
The laminated body according to any one of claims 1 to 5.
The outer layer is a scaffolding material having a thickness of 1 mm or less.
The laminated body according to any one of claims 1 to 6.
The laminated body is a tread plate, which is a laminated body.
The laminate according to claims 1 to 6, wherein the laminate is
The laminated body is a laminated body which is a support member for supporting a tread plate.