Floor mat

Abstract

This floor mat is a laminated body formed from a plurality of layers containing a chlorine-based polymer having a polymer chain including chlorine. The outermost layer of the laminated body is a transparent layer containing the chlorine-based polymer and an acrylic polymer having an acrylic polymer chain. The chlorine content of the laminated body is 10 wt% or greater.

Description

Floor covering

[0001] The present invention relates to a floor covering used for vehicles such as buildings, vehicles, and airplanes.

[0002] Conventionally, floor coverings have been installed on the floors of vehicles such as buildings, vehicles, and airplanes for the purpose of protecting the floor surface and providing anti-slip properties during walking. Since floor coverings also have a significant impact on the design of the interior, various designs such as colors, patterns, and textures may be required, and design is an important element in combination with the functional aspect. In order to balance functions such as wear resistance and design, some floor coverings have a structure in which a transparent layer for protecting the design is laminated on top of a polymer layer with a design applied by printing or transfer.

[0003] On the other hand, in vehicles such as buildings, vehicles, and airplanes, in order to reduce human casualties and damage in the event of a fire, there may be standards regarding combustion for the materials and members used in the interior, and these may also be applied to floor coverings. Among the standards regarding combustion, some have standards particularly for the amount of toxic gas generated during combustion.

[0004] Some floor coverings use a polymer having a polymer chain containing chlorine, such as polyvinyl chloride, as the main component polymer. Polymers having a polymer chain containing chlorine are less flammable than other general-purpose polymers, but hydrogen chloride gas is generated during combustion. Hydrogen chloride gas is a toxic gas and is a major factor increasing the amount of toxic gas generated during combustion. In the prior art, as a method for reducing hydrogen chloride gas, a method of using an inorganic material such as calcium carbonate or other carbonates as a chlorine capture compound has been proposed.

[0005] Patent Document 1 discloses a resin molded body that reduces the amount of corrosive gas such as hydrogen chloride gas generated during combustion by using any one of titanium oxide coated with alumina, calcium carbonate, lithium carbonate, magnesium carbonate, zeolite, barium sulfate, potassium titanate, or a mixture thereof as a chlorine capture compound in a vinyl chloride resin.

[0006] Japanese Patent No. 3475079

[0007] However, if materials like those in the prior art described in Patent Document 1 are added to the resin as chlorine-capturing compounds, the transparency of the resin is lost. In the case of floor coverings with the aforementioned laminated transparent layers, this method cannot be used because the aesthetic appeal is lost.

[0008] In other words, the present invention aims to provide a floor covering that can suppress the amount of hydrogen chloride gas generated during combustion, even in a floor covering that has a transparent layer containing a polymer having a polymer chain containing chlorine.

[0009] The means used to solve the problem is a floor covering made of a laminate consisting of multiple layers containing a chlorine-based polymer having a polymer chain containing chlorine, wherein the outermost layer of the laminate is a transparent layer containing the chlorine-based polymer and an acrylic polymer having an acrylic polymer chain, and the chlorine content in the laminate is 10% by weight or more. Furthermore, the amount of hydrogen chloride gas generated during combustion is 800 ppm / 100 cm. ２The floor covering is as follows. Furthermore, the component ratio of chlorine-containing polymer chains and acrylic polymer chains contained in the transparent layer may be 50:50 to 90:10 by mass ratio, and the acrylic polymer chains may be one or more of polymethacrylic acid, polymethacrylic acid ester, polyacrylamide, polyacrylonitrile, polyacrylic acid, and polyacrylic acid ester. In addition, the total light transmittance of the transparent layer may be 80% or more and the haze may be 30 or less, furthermore the total light transmittance of the transparent layer may be 89% or more and the haze may be 25 or less, and furthermore the total light transmittance of the transparent layer may be 90% or more and the haze may be 10 or less. Furthermore, the transparent layer may have a wear amount of 0.04 mm or less measured in an abrasion test in accordance with JIS K7204, using an abrasion wheel H-22, a load of 9.8 N, and a rotation speed of 1000 rpm. The transparent layer may also contain one or more flame retardants from among phosphorus-containing flame retardants, silicone resin, silicone-acrylic copolymer, zinc borate, hydrotalcite, and halogen-based flame retardants other than chlorine. The component ratio of chlorine-containing polymer chains to acrylic polymer chains contained in the transparent layer may be 90:10 to 95:5 by mass. The total content of the flame retardants in the transparent layer may be 5% to 30% by weight. The component ratio of chlorine-containing polymer chains to acrylic polymer chains contained in the transparent layer may be 90:10 to 95:5 by mass, and the total content of the flame retardants in the transparent layer may be 20% to 30% by weight.

[0010] According to the present invention, even in a floor covering in which a transparent layer containing a polymer having a polymer chain containing chlorine is laminated, the amount of hydrogen chloride gas generated during combustion can be reduced while maintaining the transparency of the transparent layer, thereby providing a floor covering that achieves both aesthetic appeal and safety.

[0011] This is a cross-sectional view of a floor covering according to one embodiment of the present invention. This is a cross-sectional view of a floor covering according to one embodiment of the present invention. This is a cross-sectional view of a floor covering according to one embodiment of the present invention. This is an explanatory diagram showing the state in which the test specimen is fixed to the test specimen holder. This is a schematic diagram showing a measurement test of the amount of hydrogen chloride gas generated when a test specimen is burned in a smoke emission tester.

[0012] The floor covering of the present invention is a laminate comprising a plurality of layers containing a chlorine-based polymer having a polymer chain containing chlorine, wherein the outermost layer of the laminate is a transparent layer containing the chlorine-based polymer and an acrylic polymer having an acrylic polymer chain, and the chlorine content in the laminate is 10% by weight or more. Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the embodiments described below. In this specification, "weight" and "mass", "parts by weight" and "parts by mass", and "weight%" and "mass%" are used interchangeably.

[0013] In the embodiment shown in Figure 1, the floor covering 1 consists of multiple layers containing a chlorine-based polymer having a polymer chain containing chlorine, with a transparent layer 2 on the outermost surface. Below the transparent layer 2, which is the outermost layer, there is an intermediate layer 3 and a backing layer 4. In addition, as in the embodiments shown in Figures 2 and 3, a base material 5 (and base material 5') may be provided to ensure the dimensional stability of the floor covering 1. The base material 5 (and 5') may be located below the backing layer 4, in the middle of the backing layer 4, or both below and in the middle of the backing layer 4. Alternatively, the base material 5 (5') may be provided between the intermediate layer 3 and the backing layer 4. Furthermore, as shown in Figure 4, a design layer 6 may be provided below the transparent layer 2, which is the outermost layer. The design layer 6 can be provided by various methods, such as a colored resin layer, printing or transferring a color or pattern onto the back surface of the transparent layer 2 or the surface of the intermediate layer 3. In addition, to provide anti-slip properties and design features, it is possible to form convex portions 211 and concave portions 212 on the surface 21 of the transparent layer 2 by processing such as embossing. Furthermore, the floor covering of the present invention has a chlorine content of 10% by weight or more overall, preferably 14% by weight or more. The presence of a certain amount of chlorine in the floor covering provides a certain degree of flame retardancy.

[0014] The transparent layer 2, which is the outermost layer of the floor covering of the present invention, uses a chlorine-based polymer having chlorine-containing polymer chains and an acrylic polymer having acrylic polymer chains. In the polymer components used in the transparent layer 2, which is the outermost layer, it is sufficient that a certain amount of chlorine-containing polymer chains be replaced with chlorine-free acrylic polymer chains. For this reason, a chlorine-based polymer having chlorine-containing polymer chains that do not contain acrylic polymer chains may be mixed with an acrylic polymer having chlorine-free acrylic polymer chains, or a polymer that is a copolymer having chlorine-containing polymer chains and acrylic polymer chains in the same molecule (such a copolymer polymer shall serve as both a chlorine-based polymer and an acrylic polymer) may be used alone, or a mixture thereof may be used.

[0015] Increasing the proportion of chlorine-free acrylic polymer chains in the outermost transparent layer 2 reduces the amount of hydrogen chloride gas generated during combustion. However, if the proportion of acrylic polymer chains is too high, the performance required for flooring materials, such as abrasion resistance, tends to decrease. Considering safety in the event of a fire, the floor covering of the present invention should generate 800 ppm / 100 cm of hydrogen chloride gas during combustion. ２The following is desirable: In order to reduce the amount of hydrogen chloride gas generated while maintaining the functions necessary for floor coverings other than the amount of toxic gas generated during combustion, such as abrasion resistance, slip resistance, and chemical resistance, the component ratio of chlorine-containing polymer chains to acrylic polymer chains in the transparent layer is preferably 50:50 to 90:10 by mass ratio, and more preferably 50:50 to 80:20. In another preferred embodiment, the component ratio of chlorine-containing polymer chains to acrylic polymer chains contained in the transparent layer is preferably 90:10 to 95:5 by mass ratio. Here, the chlorine-containing polymer chains in the transparent layer refer to the chlorine-based polymer that does not contain the aforementioned acrylic polymer chains, and also to the chlorine-containing polymer chain component in a copolymer having chlorine-containing polymer chains and acrylic polymer chains. The acrylic polymer chains refer to the aforementioned acrylic polymer that does not contain chlorine, and also to the acrylic polymer chain component in a copolymer having chlorine-containing polymer chains and acrylic polymer chains. For example, if a chlorine-based polymer that does not contain acrylic polymer chains and an acrylic polymer that does not contain chlorine are mixed and used as the polymer component of transparent layer 2, the mixing ratio will be the component ratio of chlorine-containing polymer chains to acrylic polymer chains in the transparent layer (I). Chlorine-containing polymer chains : Acrylic polymer chains = Mass of chlorine-based polymer : Mass of acrylic polymer ... (I) If only a copolymer containing chlorine-containing polymer chains and acrylic polymer chains (for example, a vinyl chloride-acrylic copolymer) is used as the polymer component of transparent layer 2, the composition ratio of each monomer component will be the component ratio of chlorine-containing polymer chains to acrylic polymer chains in the transparent layer (II). Chlorine-containing polymer chains : Acrylic polymer chains = Mass of chlorine-containing polymer chain component in copolymer : Mass of acrylic polymer chain component in copolymer ... (II) When a chlorine-based polymer that does not contain acrylic polymer chains, an acrylic polymer that does not contain chlorine, and a copolymer containing chlorine-containing polymer chains and acrylic polymer chains are mixed and used as the polymer component of transparent layer 2, the component ratio will be as follows (III).Chlorine-containing polymer chains: Acrylic polymer chains = Sum of the mass of chlorine-based polymer and the mass of chlorine-containing polymer chain components in the copolymer: Sum of the mass of acrylic polymer and the mass of acrylic polymer chain components in the copolymer... (III).

[0016] Any structure of the acrylic polymer chain is effective as long as it does not impede transparency, but those containing one or more of the following are more preferable: polymethacrylic acid, polymethacrylic acid ester, polyacrylamide, polyacrylonitrile, polyacrylic acid, and polyacrylic acid ester. Furthermore, the acrylic polymer having the acrylic polymer chain may be a homopolymer or a copolymer, as long as it has the above-mentioned structure. In the case of a copolymer, it may be a copolymer with other monomers that do not contain chlorine, or a copolymer with monomers that do contain chlorine. When calculating the component ratio of chlorine-containing polymer chains to acrylic polymer chains in the transparent layer, copolymers with other monomers that do not contain chlorine should be treated as chlorine-free acrylic polymers, and copolymers with monomers that contain chlorine should be treated separately from chlorine-containing polymer chains in the copolymer. The copolymer may be a random copolymer, a block copolymer, or a graft copolymer, but block copolymers and graft copolymers are preferred, and graft copolymers are more preferred.

[0017] The degree of transparency of the outermost transparent layer 2 is acceptable as long as it does not affect the required design. However, when measured according to the method compliant with JIS K7136, it is preferable that the total light transmittance is 80% or more and the haze is 30 or less, more preferably that the total light transmittance is 89% or more and the haze is 25 or less, and even more preferably that the total light transmittance is 90% or more and the haze is 10 or less.

[0018] The amount of wear of the transparent layer 2 measured in an abrasion test in accordance with JIS K7204, using an abrasion wheel H-22, a load of 9.8 N, and a rotation speed of 1000 rpm, is acceptable as long as it does not reach the design layer or colored layer during actual use. However, it is preferable that the wear be 0.3 mm or less, more preferably 0.1 mm or less, and even more preferably 0.04 mm or less.

[0019] In the outermost transparent layer 2, a flame retardant may be added to improve the flame retardancy of the floor covering, to the extent that it does not impair transparency. Suitable flame retardants include phosphorus-containing flame retardants, silicone resins, silicone-acrylic copolymers, zinc borate, hydrotalcite, and halogen-based flame retardants other than chlorine. These flame retardants can be used individually or in combination, and one or more of them may be included.

[0020] If adding a resin containing acrylic polymer chains to the transparent layer 2 tends to increase the intensity of the flame or make it difficult to extinguish during combustion tests, adding a certain amount or more of the flame retardant can balance the amount of toxic gas generated and flame retardancy. The total amount of flame retardant in the transparent layer 2 is preferably 5% to 30% by weight.

[0021] Furthermore, in order to minimize the deterioration of performance such as abrasion resistance caused by adding an acrylic polymer having an acrylic polymer chain to the transparent layer 2, when the component ratio of a chlorine-containing polymer having a chlorine-containing polymer chain is increased (specifically, when the component ratio of chlorine-containing polymer chains to acrylic polymer chains in the transparent layer 2 is 90:10 to 95:5 by mass), it is preferable from the viewpoint of improving the effect of reducing hydrogen chloride gas generation that the total content of flame retardants in the transparent layer 2 be 20% to 30% by weight.

[0022] When it is necessary to add a large amount of flame retardant to the transparent layer 2, a combination of a liquid phosphorus-based flame retardant and an inorganic flame retardant such as hydrotalcite is more preferable as a type of flame retardant that does not impair transparency. Here, the liquid phosphorus-based flame retardant is assumed to also include phosphate ester plasticizers.

[0023] If increasing the amount of flame retardant added to the transparent layer 2 reduces transparency, it may be possible to improve transparency by changing the molecular weight of the chlorine-based polymer. The molecular weight of the polymer should be selected considering a balance between maintaining transparency, performance and durability as a flooring material, and processability. For example, in the case of polyvinyl chloride, a degree of polymerization of around 700 to 1300 is generally suitable for use.

[0024] In addition, the transparent layer 2 may contain resin additives such as plasticizers, stabilizers, light stabilizers, UV absorbers, and antistatic agents as needed. Small amounts of pigments may also be added, as long as they do not interfere with the appearance of the design.

[0025] Each layer (intermediate layer 3, backing layer 4, etc.) constituting the floor covering of the present invention has a chlorine-based polymer having a chlorine-containing polymer chain as its main polymer component. Examples of chlorine-based polymers having a chlorine-containing polymer chain include polyvinyl chloride (homopolymer), chlorinated polyvinyl chloride, polyvinylidene chloride, and various vinyl chloride copolymers (e.g., vinyl acetate-vinyl chloride copolymer, ethylene-vinyl chloride copolymer, vinyl chloride-acrylic copolymer, ethylene-vinyl acetate-vinyl chloride graft copolymer, polyurethane-vinyl chloride graft copolymer, vinyl chloride-acrylic graft copolymer, etc.). These can be used individually or in combination of two or more types.

[0026] Various resin additives can be incorporated into the intermediate layer 3 and the back layer 4. For example, resin additives such as plasticizers, stabilizers, fillers, flame retardants, light stabilizers, UV absorbers, antistatic agents, lubricants, and pigments can be incorporated as needed. For example, phthalate ester plasticizers, polyester plasticizers, phosphate ester plasticizers, aliphatic dibasic acid ester plasticizers, trimellitic acid ester plasticizers, and epoxy plasticizers can be used as plasticizers; metal soaps such as barium-zinc, calcium-zinc, and magnesium-zinc, and organotin can be used as stabilizers; and carbonates such as calcium carbonate and magnesium carbonate, layered silicates such as talc, mica, and clay, hollow balloons such as fly ash balloons, shirasu balloons, and glass balloons, and titanium dioxide can be used as fillers. As flame retardants, molybdate-based flame retardants such as zinc calcium molybdate-based flame retardants, inorganic flame retardants such as zinc stannate, aluminum hydroxide, calcium hydroxide, zinc borate, and hydrotalcite, as well as phosphorus-containing flame retardants, silicone resins, silicone-acrylic copolymers, and halogen-based flame retardants other than chlorine can be used.

[0027] Various woven fabrics and nonwoven fabrics can be used as the base materials 5 and 5'. The fibers that make up the woven fabrics and nonwoven fabrics can be organic fibers such as natural fibers, chemical fibers, and synthetic fibers, or inorganic fibers such as carbon fibers and glass fibers.

[0028] The design layer 6 can be a colored resin layer, a printed film, or a printed layer formed by transfer paper or printing.

[0029] [Examples 1-4, Comparative Examples] Examples of the present invention will be described using Table 1. The samples of the examples and comparative examples in Table 1 are laminates consisting of multiple layers containing a chlorine-based polymer having a polymer chain containing chlorine, and the outermost layer is a transparent layer 2 which is transparent. Below the outermost transparent layer 2 is an intermediate layer 3, and below the intermediate layer 3 is a backing layer 4. Each layer is laminated and integrated in the order described above. (Figure 1 Structure) The transparent layer 2 has a composition of 30 parts by weight of polyester plasticizer, 3 parts by weight of stabilizer, and 8 parts by weight of phosphorus-containing flame retardant per 100 parts by weight of polymer components. The intermediate layer 3 has a composition of 45 parts by weight of polyester plasticizer, 3 parts by weight of stabilizer, 30 parts by weight of inorganic flame retardant, and 70 parts by weight of inorganic filler (calcium carbonate) per 100 parts by weight of chlorine polymer (polyvinyl chloride). The back layer 4 has a composition of 55 parts by weight of polyester plasticizer, 3 parts by weight of stabilizer, and 200 parts by weight of inorganic filler (calcium carbonate) per 100 parts by weight of chlorine polymer (polyvinyl chloride).

[0030] The amount of hydrogen chloride gas generated was compared by changing the component ratio (mass ratio) of chlorine-containing polymer chains and acrylic polymer chains in the transparent layer 2, which is the outermost layer. The component ratio (mass ratio) of chlorine-containing polymer chains and acrylic polymer chains contained in the transparent layer 2 of the examples and comparative examples was calculated according to the method described above. The calculated values ​​are shown in Table 1. The formulations of the intermediate layer 3 and the backing layer 4 were the same, and the thickness of each layer differed only slightly in the transparent layer 2 and the backing layer 4. For Example 1 and the comparative example, the thickness of the transparent layer 2 was 0.5 mm and the total thickness was 2.8 mm, while for Examples 2, 3, and 4, the thickness of the transparent layer 2 was 0.3 mm and the total thickness was 2.0 mm. In addition, in all samples of these examples and comparative examples, the transparency of the transparent layer 2, which is the outermost layer, was in the range of total light transmittance 88-99% and haze 1.8-6.7. The total light transmittance and haze were measured according to the method in accordance with JIS K7136. Furthermore, the chlorine content in the floor covering was determined by the ratio of chlorine mass per unit area of ​​the floor covering, based on the composition and the thickness of each layer. For these examples and comparative examples of floor coverings, the amount of hydrogen chloride gas generated during combustion and the abrasion resistance were evaluated. The chlorine-based polymer and acrylic-based polymer used in transparent layer 2 of Table 1 are shown below. A: Polyvinyl chloride (degree of polymerization 1000) B: Vinyl chloride-alkyl acrylate copolymer C: Ethylene-butyl acrylate-carbon monoxide copolymer D: Methyl methacrylate-butyl acrylate copolymer *B is both a chlorine-based polymer and an acrylic-based polymer, but for convenience, it is listed as an acrylic-based polymer in the table. Note that in B, the ratio of the mass of the polymer chain component derived from vinyl chloride to the mass of the polymer chain component derived from alkyl acrylate in the copolymer is 80:20.

[0031] The amount of hydrogen chloride gas generated during combustion was measured using a SMOKE DENSITY CHAMBER (smoke emission tester) from Fire Testing Technology, under test conditions compliant with the smoke emission test (ISO 5659-2 with pilot light). The size of the test specimen, floor covering 1, was 75 mm x 75 mm. The back, sides, and periphery of the surface of the test specimen, except for the center (65 mm x 65 mm) of the surface 21 of the transparent layer 2 which is the combustion surface of the test specimen, were wrapped in aluminum foil 8. As shown in Figure 5 (5-1), the test specimen was placed on the base 72 of the stainless steel test specimen holder 7 with a glass fiber spacer 92 and a 2 mm thick aluminum plate 91 on top, with the combustion surface facing upwards. The holding frame 71 of the test specimen holder 7, which has a 65 mm x 65 mm opening in the center, was then placed over it, and the test specimen was set in the test specimen holder 7 as shown in Figure 5 (5-2). Figure 6 shows the inside of the smoke emission tester. As shown in Figure 6, a test specimen holder 7 with the test specimen fixed inside the smoke emission tester 10 was set, and a combustion test was performed with the chamber 101 sealed. The test involved heating the surface of the test specimen with a heater 102 at 25 kW / m². ２ The test was conducted under conditions of applying radiant heat and having a gas burner flame source 103. Eight minutes after the start of the test, 100cc of gas from inside the chamber was collected in a detector tube 104 pre-installed in the center of the chamber, and the amount of hydrogen chloride gas generated was measured. The detector tube 104 used was one with a measurement range of 10 to 1000 ppm, manufactured by Gastec Co., Ltd. From the measured values, the amount of hydrogen chloride gas generated per unit area of ​​the floor covering was calculated. Abrasion resistance was evaluated by the amount of wear on the test piece (transparent layer side) in the abrasion test method using abrasion wheels according to JIS K7204. The abrasion test machine presses a pair of abrasion wheels onto a rotating test piece under a specified load, and the test piece is worn down by the abrasion wheels. The test conditions were abrasion wheel H-22, load 9.8N, and rotation speed 1000 rpm. Here, the load refers to the load applied to one abrasion wheel.

[0032]

[0033] The amount of hydrogen chloride gas generated decreased as the proportion of chlorine-containing polymer chains in the outermost transparent layer 2 decreased. Comparing Examples 1 and 3, in which the polymer component of transparent layer 2 is a mixture of vinyl chloride resin (a chlorine-based polymer) and acrylic polymer, with Examples 2 and 4, in which the polymer component of transparent layer 2 is a copolymer having chlorine-containing polymer chains and chlorine-free acrylic polymer chains, or a blend of a copolymer having chlorine-containing polymer chains and chlorine-free acrylic polymer chains with an acrylic polymer, it can be seen that even with similar chlorine content, Examples 2 and 4, which use a copolymer having chlorine-containing polymer chains and chlorine-free acrylic polymer chains, suppress the amount of hydrogen chloride gas generated during combustion. In Example 4, the amount of hydrogen chloride gas generated was the lowest, but the amount of wear increased slightly.

[0034] Table 2 shows the transparency of the outermost transparent layer 2. A 0.3 mm thick single-layer sheet was prepared by mixing chlorine-based polymers and each acrylic polymer in the ratios shown in the table. Total light transmittance and haze measurements were performed visually and according to the JIS K7136 method. Visual evaluation was categorized as: very good transparency (◎), good transparency (〇), and slightly cloudy but acceptable (△). The acrylic polymers used in Table 2 are listed below. Note that the composition of transparent layer 2 in Table 2 is the same as that of the transparent layer 2 of the floor covering in Table 1, except for the polymer type. The chlorine-based polymers and acrylic polymers used in Table 1 are also used in Table 2. E: Mixture of acrylic copolymers F: Alkyl methacrylate / methacrylic acid copolymer G: Alkyl methacrylate / alkyl acrylate copolymer H: Alkyl methacrylate / alkyl acrylate / styrene copolymer I: Butadiene / Alkyl methacrylate / Alkyl acrylate / styrene copolymer

[0035]

[0036] The transparency of the outermost transparent layer 2 varies depending on the type of polymer. A total light transmittance of 80% or more and a haze of 30 or less is considered to have practical transparency. To ensure even higher aesthetic appeal and design quality, a total light transmittance of 90% or more and a haze of 10 or less is preferable.

[0037] [Examples 5-6] Examples 5 and 6 of the present invention will be described with reference to Table 3. The samples of Examples 5 and 6 are laminates consisting of multiple layers containing a chlorine-based polymer having a polymer chain containing chlorine, and the outermost layer is a transparent layer 2 which is transparent. Below the outermost transparent layer 2 is an intermediate layer 3, and below the intermediate layer 3 is a backing layer 4. Each layer is laminated and integrated in the order described above. (Figure 1 Structure) The transparent layer 2 of Example 5 has a composition of 30 parts by weight of polyester plasticizer, 3 parts by weight of stabilizer, 24 parts by weight of phosphorus-containing flame retardant, and 5 parts by weight of hydrotalcite per 100 parts by weight of polymer components. The transparent layer 2 of Example 6 has a composition of 20 parts by weight of polyester plasticizer, 3 parts by weight of stabilizer, 32 parts by weight of phosphorus-containing flame retardant, and 10 parts by weight of hydrotalcite per 100 parts by weight of polymer components. The intermediate layer 3 has a composition of 100 parts by weight of chlorine polymer (polyvinyl chloride), 45 parts by weight of polyester plasticizer, 3 parts by weight of stabilizer, 30 parts by weight of inorganic flame retardant, and 70 parts by weight of inorganic filler (calcium carbonate). The back layer 4 has a composition of 100 parts by weight of chlorine polymer (polyvinyl chloride), 55 parts by weight of polyester plasticizer, 3 parts by weight of stabilizer, 16 parts by weight of phosphorus-containing flame retardant, and 230 parts by weight of inorganic filler (calcium carbonate).

[0038] For the transparent layer 2, which is the outermost layer, the component ratio (mass ratio) of chlorine-containing polymer chains and acrylic polymer chains was changed, and the amount of hydrogen chloride gas generated was compared. The component ratio (mass ratio) of chlorine-containing polymer chains and acrylic polymer chains contained in the transparent layer 2 of Examples 5 and 6 was calculated according to the method described above. The calculated values ​​are shown in Table 3. The formulations of the intermediate layer 3 and the backing layer 4 were the same, and the thickness of the transparent layer 2 in Examples 5 and 6 was 0.3 mm, with a total thickness of 2.0 mm. In Examples 5 and 6, as well as the comparative examples and Example 1 listed in Table 3, the transparency of the transparent layer 2, which is the outermost layer, was in the range of 89-99% total light transmittance and 1.8-16.2 haze in all samples. The total light transmittance and haze were measured according to the method in accordance with JIS K7136. The chlorine content in the floor covering was determined from the formulation and the thickness of each layer, by the ratio of chlorine mass contained in the mass per unit area of ​​the floor covering. For the floor coverings of Examples 5 and 6, the amount of hydrogen chloride gas generated during combustion and the abrasion resistance were measured and evaluated in the same manner as for the floor coverings of Examples 1 to 4 and the Comparative Example. The results for the Comparative Example and Example 1 are also shown in Table 3. The chlorine-based polymer and acrylic-based polymer used in transparent layer 2 of Table 3 are shown below. A: Polyvinyl chloride (degree of polymerization 1000) C: Ethylene-butyl acrylate-carbon monoxide copolymer G: Alkyl methacrylate / alkyl acrylate copolymer H: Alkyl methacrylate / alkyl acrylate / styrene copolymer In Example 6, the mixing ratio of G and H (G / H) is 1 / 4 by mass.

[0039]

[0040] In Examples 5 and 6, even when the component ratio of chlorine-containing polymer chains in the outermost transparent layer 2 was 95, increasing the flame retardant ratio in the transparent layer 2 reduced the amount of hydrogen chloride gas generated. Furthermore, the high component ratio of chlorine-containing polymer chains in the transparent layer 2 maintained the same level of wear as the comparative example.

[0041] In Table 4, regarding the transparency of the outermost transparent layer 2, a single-layer sheet with a thickness of 0.3 mm was prepared by mixing a chlorine-based polymer and each acrylic-based polymer so as to obtain the ratios shown in the table, and the total light transmittance and haze were measured by visual confirmation and a method compliant with JIS K7136. The visual evaluation was made as being very good transparency (◎), good transparency (〇), or slightly turbid but acceptable (△). The chlorine-based polymers and acrylic-based polymers used in Table 4 are shown below. Note that the blending composition of the transparent layer 2 in Table 4 is such that Sample No. 11 has the same blend as the transparent layer 2 of the floor covering in Example 5, Sample No. 13 has the same blend as the transparent layer 2 of the floor covering in Example 6, and Samples No. 12, 14, and 15 use the same blend as the transparent layer 2 of the floor covering in Example 6 except for the polymer species, and the chlorine-based polymers and acrylic-based polymers used in Table 3 are also used in Table 4. A: Polyvinyl chloride (degree of polymerization 1000) G: Alkyl methacrylate / alkyl acrylate copolymer H: Alkyl methacrylate / alkyl acrylate / styrene copolymer J: Polyvinyl chloride (degree of polymerization 700) Note that in Sample No. 13, the mixing ratio (G / H) of G and H is 1 / 4 by mass ratio. In Samples No. 14 and 15, the mixing ratio (A / J) of A and J is 50 / 45 by mass ratio.

[0042]

[0043] The transparency of the outermost transparent layer 2 varies depending on the degree of polymerization of the chlorine-based polymer to be blended and the type of acrylic-based polymer, but relatively good transparency can be maintained when the component ratio of the polymer chain containing chlorine and the acrylic-based polymer chain is 95:5. From Table 4, if the total light transmittance is 80% or more and the haze is 30 or less, it is a practical transparency. To ensure a higher aesthetic appearance and design quality, it is more preferable that the total light transmittance is 89% or more and the haze is 25 or less.

[0044] According to the present invention, even in a floor covering having a transparent layer containing a polymer having a polymer chain containing chlorine laminated thereon, in applications such as buildings and vehicles such as railways and airplanes, it is possible to provide a floor covering that is safer for the human body while achieving both functions required for a floor material such as design quality and abrasion resistance.

[0045] While the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on Japanese Patent Application No. 2025-026612 filed on February 21, 2025, the content of which is incorporated herein by reference.

[0046] 1 Floor covering 2 Transparent layer (outermost layer) 21 Surface 3 Intermediate layer 4 Back layer 5, 5' Base material 6 Design layer 7 Specimen holder 71 Holding frame 72 Base 8 Aluminum foil 9 Spacer 91 Aluminum plate 92 Glass fiber 10 Smoke generation tester 101 Chamber 102 Heater 103 Ignition source 104 Detection tube

Claims

1. A floor covering comprising a laminate consisting of multiple layers containing a chlorine-based polymer having a chlorine-containing polymer chain, wherein the outermost layer of the laminate is a transparent layer containing the chlorine-based polymer and an acrylic polymer having an acrylic polymer chain, and the chlorine content in the laminate is 10% by weight or more.

2. The amount of hydrogen chloride gas generated during combustion is 800 ppm / 100 cm. ２ The floor covering according to claim 1, which is as follows:

3. The floor covering according to claim 1 or claim 2, wherein the component ratio of chlorine-containing polymer chains and acrylic polymer chains contained in the transparent layer is 50:50 to 90:10 by mass ratio.

4. The floor covering according to claim 1 or claim 2, wherein the acrylic polymer chain is one or more of the following: polymethacrylic acid, polymethacrylic acid ester, polyacrylamide, polyacrylonitrile, polyacrylic acid, and polyacrylic acid ester.

5. The floor covering according to claim 1 or claim 2, wherein the total light transmittance of the transparent layer is 80% or more and the haze is 30 or less.

6. The floor covering according to claim 5, wherein the total light transmittance of the transparent layer is 89% or more and the haze is 25 or less.

7. The floor covering according to claim 5, wherein the total light transmittance of the transparent layer is 90% or more and the haze is 10 or less.

8. The floor covering according to claim 1 or claim 2, wherein the amount of wear of the transparent layer measured in an abrasion test in accordance with JIS K7204, using an abrasion wheel H-22, a load of 9.8 N, and a rotation speed of 1000 rpm, is 0.04 mm or less.

9. The floor covering according to claim 1 or claim 2, wherein the transparent layer contains one or more flame retardants selected from phosphorus-containing flame retardants, silicone resin, silicone-acrylic copolymer, zinc borate, hydrotalcite, and halogen-based flame retardants other than chlorine.

10. The floor covering according to claim 1 or claim 2, wherein the component ratio of chlorine-containing polymer chains and acrylic polymer chains contained in the transparent layer is 90:10 to 95:5 by mass ratio.

11. The floor covering according to claim 9, wherein the total amount of the flame retardant in the transparent layer is 5% by weight to 30% by weight.

12. The floor covering according to claim 9, wherein the component ratio of chlorine-containing polymer chains and acrylic polymer chains contained in the transparent layer is 90:10 to 95:5 by mass ratio, and the total amount of the flame retardant in the transparent layer is 20% to 30% by weight.

Images