Patent Application
20240240368
One or more embodiments of the present invention relate to flame-retardant upholstered furniture containing a flame-blocking fabric.
Conventionally, flame-blocking fabrics containing halogen-containing fibers and other fibers have been used in flame-retardant upholstered furniture. For example, Patent Documents 1 to 3 disclose use of a flame-blocking fabric in upholstered furniture, the flame-blocking fabric containing modacrylic fibers made of a copolymer of acrylonitrile and a halogen-containing vinyl monomer, which are used as halogen-containing fibers, and other fibers such as cellulose fibers.
However, modacrylic fibers used in conventional flame-blocking fabrics such as the flame-blocking fabrics disclosed in Patent Documents 1 to 3 generally contains an antimony compound as a flame retardant, and there has been concern that the antimony compound eluted or discharged from the flame-blocking fabric containing such modacrylic fibers has environmental impact. Accordingly, there has been room for improvement of flame-retardant upholstered furniture in which the flame-blocking fabric is used. Also, an inner structure such as a urethane foam may be ignited during combustion due to insufficient flame-blocking ability of flame-retardant upholstered furniture, and therefore, both achievement of excellent texture and further improvement in flame-blocking properties have been required.
One or more embodiments of the present invention provide flame retardant upholstered furniture that has reduced environmental impact and has favorable flame-blocking properties as well as excellent texture.
One or more embodiments of the present invention relate to flame-retardant upholstered furniture including: an inner structure; and a flame-blocking fabric that covers the inner structure, wherein the flame-blocking fabric contains flame-retardant modacrylic fibers (A) in an amount of 60 mass % or more and 90 mass % or less, and cellulose fibers (B) in an amount of 10 mass % or more and 40 mass % or less, with respect to an overall mass of the flame-blocking fabric, the flame-retardant modacrylic fibers (A) contain a magnesium compound, the flame-blocking fabric contains the magnesium compound in an amount of 1.5 mass % or more and 13.5 mass % or less with respect to the overall mass of the flame-blocking fabric, and time until both afterflame and afterglow go out is 120 seconds or less when measured through a flammability test based on BS 5852: 2006.
One or more embodiments of the present invention can provide flame retardant upholstered furniture that has reduced environmental impact and has favorable flame-blocking properties as well as excellent texture.
The inventors of one or more embodiments of the present invention found that, by covering an inner structure of upholstered furniture with a fabric obtained by blending flame-retardant modacrylic fibers (A) containing magnesium compound as a flame retardant in an amount within a predetermined range and cellulose fibers (B) at a predetermined ratio, it is possible to reduce concern regarding the environmental impact, achieve excellent flame-blocking properties (flame retardancy), reduce time until both afterflame and afterglow go out, and sufficiently secure the texture and comfort of the inner structure. In particular, the inventors found that, in the case where the upholstered furniture is a chair such as a sofa or a couch, it is possible to achieve high flame retardancy while sufficiently securing the unique texture and comfort of a urethane foam itself used as the material of the internal structure.
In one or more embodiments of the present invention, the flame-blocking fabric contains a magnesium compound as a flame retardant and substantially no antimony compound, thus making it possible to reduce concern regarding the environmental impact and reduce the cost. In this specification, the wording “containing substantially no antimony compound” means that an antimony compound serving as a flame retardant is not added to a fiber or a fabric on purpose.
In this specification, “time until both afterflame and afterglow go out” can be measured through a flammability test based on BS 5852: 2006.
Flame-blocking fabrics are favorably used for applications requiring flame-blocking ability. The flame blocking ability as used herein means an ability of a flame-blocking fabric to prevent flame from moving to the opposite side due to the flame-blocking fabric being charred and blocking flame when exposed to the flame.
In one or more embodiments of the present invention, the flame-blocking fabric contains flame-retardant modacrylic fibers (A) and cellulose fibers (B).
The flame-blocking fabric may contain the flame-retardant modacrylic fibers (A) in an amount of 60 mass % or more and 90 mass % or less and the cellulose fibers (B) in an amount of 10 mass % or more and 40 mass % or less, and the flame-retardant modacrylic fibers (A) in an amount of 70 mass % or more and 80 mass % or less and the cellulose fibers (B) in an amount of 20 mass % or more and 30 mass % or less, with respect to the overall mass of the fabric. If the content of the flame-retardant modacrylic fibers (A) is less than 60 mass %, the flame-blocking fabric will have insufficient flame retardancy, and if the content of the flame-retardant modacrylic fibers (A) exceeds 90 mass %, the cellulose fibers (B) will be insufficient, resulting in an insufficient ability to form a char layer during combustion. Also, if the content of the cellulose fibers (B) is less than 10 mass %, the ability of the flame-blocking fabric to form a char layer during combustion will be insufficient, and if the content of the cellulose fibers (B) exceeds 40 mass %, the flame-retardant acrylic fibers (A) will be insufficient, resulting in insufficient flame retardancy of the flame-blocking fabric, which is not preferable.
The flame-blocking fabric may contain other fibers as long as the object and the effects of one or more embodiments of the present invention are not inhibited. When natural fibers are used as the other fibers, examples thereof include natural animal fibers such as wool fibers, mohair fibers, cashmere fibers, camel fibers, alpaca fibers, angora fibers, and silk fibers. Examples of chemical fibers include polyester fibers, polyamide fibers, aramid fibers, polylactic acid fibers, acrylic fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, polychlal fibers, polyethylene fibers, polyurethane fibers, polyoxymethylene fibers, polytetrafluoroethylene fibers, benzoate fibers, polyphenylene sulfide fibers, polyether ether ketone fibers, polybenzazole fibers, polyimide fibers, and polyamide-imide fibers. Also, flame-retardant polyester, polyethylene naphthalate fibers, melamine fibers, acrylate fibers, polybenzoxide fibers may be used. Other examples include oxidized acrylic fibers, carbon fibers, glass fibers, and activated carbon fibers. In addition, regenerated collagen fibers, regenerated protein fibers, cellulose acetate fibers, promix fibers, and the like may also be used.
The above-mentioned flame-blocking fabric may contain the other fibers in an amount of 20 mass % or less, or 10 mass % or less, or 8 mass % or less, with respect to the overall mass of the fabric.
The flame-blocking fabric is not particularly limited, but may be a knitted fabric from the viewpoint of texture, feel, moisture absorbency, and the like. The knitted fabric may be a warp-knitted fabric or a weft-knitted fabric, but may be a weft-knitted fabric because a weft-knitted fabric has excellent stretchability and drapability and can easily cover the inner structure. The knitted fabric may contain mixed yarns, blended yarns, and core yarns made of the flame-retardant modacrylic fibers (A) and the cellulose fibers (B), or may be formed by interknitting fiber yarns made of the flame-retardant modacrylic fibers (A) and fiber yarns made of the cellulose fibers (B), or may be formed by layering a knitted fabric knitted out of fiber yarns made of the flame-retardant modacrylic fibers (A) and a knitted fabric knitted out of fiber yarns made of the cellulose fibers (B), but is not limited thereto.
The basis weight of the flame-blocking fabric may be 120 g/m2 or more and 220 g/m2 or less, or 140 g/m2 or more and 200 g/m2 or less. If the basis weight of the flame-blocking fabric is less than 120 g/m2, there is a risk that the char layer formed during combustion will have a low density, resulting in an insufficient ability to prevent the ignition of a urethane foam used as an inner structure of upholstered furniture such as a sofa or a couch. If the basis weight of the flame-blocking fabric exceeds 220 g/m2, the char layer formed during combustion will have favorable flame-blocking ability, but there is a risk that the texture of a urethane foam used as an inner structure of upholstered furniture such as a sofa or a couch will be impaired. The flame-blocking fabric may be used in a single layer, or the flame-blocking fabrics may be layered and used in two or more layers.
The flame-blocking fabric may contain an antistatic agent, a thermal coloration inhibitor, a light resistance improver, a whiteness improver, a devitrification inhibitor, and the like, as needed.
In one or more embodiments of the present invention, the flame-blocking fabric has desired flame retardancy and have excellent texture characteristics. Furthermore, in one or more embodiments of the present invention, upholstered furniture containing the flame-blocking fabric has excellent characteristics derived from the flame-blocking fabric, namely excellent flame-blocking properties and excellent texture.
Regarding the content of the magnesium compound serving as a flame retardant in the flame-blocking fabric, the content of the magnesium compound in the entire fabric can be determined by performing fluorescence X-ray analysis on the fabric itself. The mass of the cellulose fibers (B) contained in the flame-blocking fabric can be determined by, for example, immersing the fabric in an organic solvent such as dimethylsulfoxide (DMSO), dimethylformamide (DMF), or dimethylacetamide (DMAc), heating the fabric to dissolve the flame-retardant modacrylic fibers (A), and extracting the remaining cellulose fibers (B). Furthermore, the magnesium compound contained in the flame-retardant modacrylic fibers (A) can be determined by measuring the insoluble component in the organic solvent solution.
A magnesium compound is used as aflame retardant in the flame-blocking fabric from the viewpoint of ease of forming a char layer during combustion.
The content of the magnesium compound serving as a flame retardant in the flame-blocking fabric to the overall mass of the fabric may be 1.5 mass % or more and 13.5 mass % or less, 2.0 mass % or more and 9.0 mass % or less, 2.5 mass % or more and 8.5 mass % or less, 3.0 mass % or more and 8.0 mass % or less, or 3.5 mass % or more and 7.5 mass % or less. If the flame-blocking fabric contains the flame retardant in an amount of less than 1.5 mass %, the flame-blocking ability is insufficient during combustion, resulting in an insufficient ability to prevent the ignition of a urethane foam used as an inner structure of upholstered furniture such as a sofa or a couch. In order to achieve high flame retardancy, it is preferable that the flame-blocking fabric contains the magnesium compound in a larger amount. However, if the content of the magnesium compound exceeds 13.5 mass %, there is a risk that the texture, the feel, the fiber strength, and the fabric strength will be impaired.
The average particle diameter of the magnesium compound represented as a median diameter may be 0.3 μm or more, 0.3 μm or more and 2.0 μm or less, or 0.5 μm or more and 1.5 μm or less. When the average particle diameter is 0.3 μm or more, the surface area of the magnesium compound particle does not excessively increase, and electrostatic generation is suppressed during a fiber processing step such as spinning, which facilitates the processing. When the average particle diameter is 2.0 μm or less, blockage of a spinneret is avoided during a spinning process, resulting in favorable productivity. In this specification, the average particle diameter of the magnesium compound, for example, in the form of a powder can be measured through laser diffractometry, and the average particle diameter of the magnesium compound in a dispersion (dispersion liquid) obtained by dispersing the magnesium compound in water or an organic solvent can be measured through laser diffractometry or by using a dynamic light scattering method.
In one or more embodiments of the present invention, the magnesium compound is contained in the flame-retardant acrylic fibers (A) from the viewpoint of imparting the flame-blocking properties to a fabric. Due to the magnesium compound serving as aflame retardant being contained in the flame-retardant acrylic fibers (A) containing acrylonitrile and a halogen-containing vinyl monomer, when flame comes into contact with a fabric produced using yarns containing the flame-retardant acrylic fibers (A), the flame-retardant acrylic fibers (A) foam and thus form a favorable char layer, resulting in an improvement in the flame-blocking properties. In particular, when the flame-retardant acrylic fibers (A) are used together with natural cotton fibers, charring is further promoted, resulting in an improvement in the flame-blocking properties. The content of the magnesium compound in the flame-retardant acrylic fibers (A) may be 2 mass % or more and 15 mass % or less, 3 mass % or more and 10 mass % or less, or 4 mass % or more and 9.5 mass % or less, with respect to the overall mass of the flame-retardant acrylic fibers. When the content of the magnesium compound is 2 mass % or more, the flame retardancy increases. Meanwhile, when the content of the magnesium compound is 15 mass % or less, the insulation resistance value does not increase during fiber processing such as spinning, and electrostatic generation is suppressed, and thus an issue such as winding does not occur during a carding process, which facilitates the processing.
Examples of the magnesium compound include magnesium oxide, magnesium peroxide, magnesium hydroxide, magnesium fluoride, magnesium chloride, magnesium bromide, magnesium iodide, magnesium hydride, magnesium diboride, magnesium nitride, magnesium sulfide, magnesium carbonate, calcium magnesium carbonate, magnesium nitrate, magnesium sulfate, magnesium sulfite, magnesium perchlorate, trimagnesium phosphate, magnesium permanganate, and magnesium phosphate. Of these compounds, magnesium oxide and magnesium hydroxide may be used from the viewpoint of ease of handling. Furthermore, magnesium hydroxide may be used from the viewpoint of Mohs hardness. One of the magnesium compounds may be used alone, or two or more of the magnesium compounds may be used in combination.
The Mohs hardness of the magnesium compound may be less than 5. The “Mohs hardness” herein is the indicator of mineral hardness. For example, a Mohs hardness of 5 is a degree of hardness at which making a scratch with a knife is not easy but possible, and a Mohs hardness of 6 is a degree of hardness at which making a scratch with a knife is difficult and the knife is damaged. A magnesium hydroxide compound and magnesium oxide can be used to ensure the same flame retardancy as that exhibited by an antimony compound, which is a conventional flame retardant. Furthermore, in the case of spinning fibers in which the above-mentioned compound is dispersed, fibers containing a magnesium hydroxide compound can be spun more stably than fibers containing a magnesium oxide compound. The reason for this is a matter of speculation, but is assumed to be as follows. That is, since a magnesium hydroxide compound, which has a Mohs hardness of about 3, is softer than a magnesium oxide compound, which has a Mohs hardness of about 7, abrasion of a cutter blade is suppressed when the flame-blocking fabric or the flame-retardant modacrylic fiber is cut, and thus abrasion of a spinning machine is suppressed.
The magnesium hydroxide compound is not particularly limited, but is selected from, for example, powder obtained by pulverizing natural brucite, powder obtained by neutralizing an aqueous solution of a magnesium salt with an alkali, powder obtained by treating magnesium hydroxide particles with a phosphate, a borate, or the like, and a magnesium hydroxide compound obtained using a method of hydrating magnesium oxide to gradually generate magnesium hydroxide, etc. Furthermore, the magnesium hydroxide compound may have a coating layer that is adsorbed by an adsorbable substance around the particles of the magnesium hydroxide compound, or that is formed through surface treatment. In particular, a magnesium hydroxide compound having a coating layer formed through surface treatment with a silane coupling agent is preferable from the viewpoint of suppressing static electricity. The reason why suppression of static electricity is improved through surface treatment with a silane coupling agent is a matter of speculation, but is considered to be as follows. It is conceivable that performing silane coupling treatment on the surface of a magnesium hydroxide particle improves the compatibility of the flame-retardant modacrylic fibers (A) with the magnesium hydroxide subjected to the silane coupling treatment, which results in suppression of static electricity. Furthermore, when a process of applying oil to the fiber surface is performed for the purpose of improving the processability, an effect of the oil sufficiently reaches the surface of the magnesium hydroxide particle as well, and thus the processability is significantly improved. There is no particular limitation on the type of silane coupling agent as long as the compatibility with an acrylonitrile copolymer is improved, and both a cross-linked silane coupling agent and a non-cross-linked silane coupling agent can be used.
The acrylonitrile copolymer may be a copolymer containing acrylonitrile in an amount of 30 mass % or more and 85 mass % or less, one or more halogen-containing monomers selected from the group consisting of halogen-containing vinyl monomers and halogen-containing vinylidene monomers in an amount of 15 mass % or more and 65 mass % or less, and another copolymerizable vinyl monomer in an amount of 0 mass % or more and 3 mass % or less, or a copolymer containing acrylonitrile in an amount of 30 mass % or more and 85 mass % or less, one or more halogen-containing monomers selected from the group consisting of halogen-containing vinyl monomers and halogen-containing vinylidene monomers in an amount of 15 mass % or more and 65 mass % or less, and a sulfonic group-containing monomer in an amount of 0 mass % or more and 3 mass % or less. Furthermore, the acrylonitrile copolymer may be a copolymer containing acrylonitrile in an amount of 39.9 mass % or more and 70 mass % or less, a vinyl chloride monomer and/or a vinylidene chloride monomer in an amount of 29.9 mass % or more and 60 mass % or less, and a sulfonic group-containing monomer in an amount of 0.1 mass % or more and 3 mass % or less. Using such an acrylonitrile copolymer improves the thermal resistance and the flame retardancy of the modacrylic fibers. The other copolymerizable vinyl monomer above is not particularly limited as long as it is copolymerizable with acrylonitrile.
Examples of the halogen-containing monomers include halogen-containing vinyl and halogen-containing vinylidene. Examples of the halogen-containing vinyl include vinyl chloride and vinyl bromide, and examples of the halogen-containing vinylidene include vinylidene chloride and vinylidene bromide. One of these halogen-containing monomers may be used alone, or two or more of these halogen-containing monomers may be used in combination. Vinyl chloride is preferable to vinylidene chloride. In the case of using vinyl chloride, blending a magnesium compound in a specific blend amount makes it likely that a char layer is formed during combustion, and thus high flame retardancy is exhibited. The mechanism behind this is not clear, but it is assumed that, when vinyl chloride is present, a magnesium compound functions as an intumescent flame retardant, and thus a foamed char layer, namely an intumescent, is likely to be formed during combustion. If vinylidene chloride is used, when a magnesium compound is used as a flame retardant, a copolymer is colored, and its use for clothing is restricted. However, coloring does not progress in the case of using vinyl chloride, which is preferable.
There is no particular limitation on the other copolymerizable vinyl monomer, and examples thereof include unsaturated carboxylic acids such as acrylic acid and methacrylic acid, salts of the unsaturated carboxylic acids, methacrylic acid esters such as methyl methacrylate, esters of unsaturated carboxylic acids such as glycidyl methacrylate, vinyl esters such as vinyl acetate and vinyl butyrate, and sulfonic group-containing monomers. Examples of the sulfonic group-containing monomers include allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, isoprenesulfonic acid, and 2-acrylamido-2-methylpropanesulfonic acid, and metallic salts (e.g., sodium salts) thereof and amine salts thereof. One of the sulfonic group-containing monomers may be used alone, or two or more of the sulfonic group-containing monomers may be used in combination. The sulfonic group-containing monomer is used as needed, and when the content of the sulfonic group-containing monomer in the acrylonitrile copolymer is 3 mass % or less, the production stability in the spinning process will be very high.
The acrylonitrile copolymer can be obtained through known polymerization methods such as bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization. In particular, suspension polymerization, emulsion polymerization, or solution polymerization is preferable from an industrial point of view.
The flame-retardant modacrylic fiber (A) is made of the above-mentioned acrylonitrile copolymer, and is used to improve the flame retardancy of the flame-blocking fabric. The flame-retardant modacrylic fiber (A) is charred during combustion and thus serves to deplete oxygen inside the flame-blocking fabric and to help prevention of the entrance of flame on the surface of the fabric.
The flame-retardant modacrylic fiber (A) is a modacrylic fiber that is capable of suppressing generation of carbon monoxide, which is a harmful gas, during combustion due to the magnesium compound being contained as a flame retardant compared with a modacrylic fiber containing an antimony compound, has excellent spinnability while suppressing the environmental impact, is less colored (has high lightness), and has high flame retardancy. It is preferable that the flame-retardant modacrylic fiber (A) contains the magnesium compound inside the flame-retardant modacrylic fiber from the viewpoint of flame retardancy, and it is more preferable that the magnesium compound is uniformly dispersed inside the flame-retardant modacrylic fiber.
The single-fiber strength of the flame-retardant modacrylic fiber (A) may be 1.0 cN/dtex or more and 4.0 cN/dtex or less, or 1.5 cN/dtex or more and 3.5 cN/dtex or less, for example, from the viewpoint of durability. The elongation at break of the flame-retardant modacrylic fiber (A) may be 20% or more and 40% or less, or 20% or more and 30% or less, for example, from the viewpoint of practicality. The single-fiber strength and the elongation at break of a long fiber (filament) can be measured in accordance with JIS L 1013, and those of a staple fiber can be measured in accordance with JIS L 1015.
The flame-retardant modacrylic fiber (A) may be a staple fiber or a long fiber, and it is possible to select which one is to be used, as appropriate, depending on how it is to be used. Although the single fiber fineness is selected as appropriate depending on the type of flame-blocking fabric, the single fiber fineness may be 1 dtex or more and 50 dtex or less, 1.5 dtex or more and 30 dtex or less, or 1.7 dtex or more and 15 dtex or less. The cut length is selected as appropriate depending on the type of flame-blocking fabric. For example, a short-cut fiber (with a fiber length of 0.1 mm or more and 5 mm or less), a staple fiber (with a fiber length of 6 mm or more and 128 mm or less), or a long fiber (filament) that is not cut at all can be used. For spinning, the cut length of the flame-retardant modacrylic fiber (A) may be 32 mm or more and 128 mm or less, or 38 mm or more and 76 mm or less.
The flame-retardant modacrylic fiber (A) may contain, as needed, another flame retardant whose environmental impact is of less concern when eluted or discharged, other than the magnesium compound. Also, the flame-retardant modacrylic fiber (A) may contain, as needed, other additives such as an antistatic agent (also called a “static control agent”), a thermal coloration inhibitor, a light resistance improver, a whiteness improver, a devitrification inhibitor, and a coloring agent. Note that the other additives may be applied to the surface of the fiber, and there is no particular limitation on an application method. The application may be performed through spraying and may be performed after cutting.
There is no particular limitation on a method for producing the flame-retardant modacrylic fiber (A), but the modacrylic fiber can be produced by spinning a composition containing an acrylonitrile copolymer (preferably an acrylonitrile copolymer containing at least acrylonitrile and a halogen-containing monomer) and the magnesium compound, followed by heat treatment. Specific examples of the production method include known methods such as a wet spinning method, a dry spinning method, and a semi-dry semi-wet method. The flame-retardant modacrylic fiber (A) may be produced through wet spinning from the viewpoint of uniformly dispersing the magnesium compound inside the fiber. In a modacrylic fiber obtained through wet spinning, the average particle diameter of the magnesium compound is substantially the same as the average particle diameter of the magnesium compounds in the spinning solution. For example, in the case of the wet spinning method, the flame-retardant modacrylic fiber (A) can be produced as follows. That is, a spinning solution is extruded into a coagulation bath through a nozzle and is thus coagulated, followed by drawing, washing using water, drying, heat treatment, and, if needed, crimping and cutting, as in the case of a common modacrylic fiber, except that the spinning solution is obtained by dissolving the above-mentioned acrylonitrile copolymer in an organic solvent and then adding a magnesium compound thereto. Examples of the organic solvent include DMSO, DMF, DMAc, and acetone, but an inorganic solvent such as an aqueous solution of a rhodan salt or an aqueous solution of nitric acid may also be used.
The cellulose fiber (B) is used to maintain the strength of the flame-blocking fabric, and serves to maintain the strength of a char layer during combustion. Specific examples of the cellulose fiber (B) include natural cellulose fibers such as a cotton fiber, a kapok fiber, a flax fiber, a hemp fiber, a ramie fiber, a jute fiber, a Manila hemp fiber, and a kenaf fiber, and regenerated cellulose fibers such as rayon, polynosic, cupra, and lyocell. One of these types of cellulose fibers (B) may be used alone, or two or more of these types of cellulose fibers (B) may be used in combination. These cellulose fibers may be subjected to processing for imparting flame retardancy. Furthermore, the regenerated cellulose fiber may contain a component that imparts functionality as in the case of a silicic acid-containing cellulose fiber, as long as a problem is not caused during fiber processing. A natural cotton fiber can be favorably used as the cellulose fiber (B) from the viewpoint of the strength and the texture.
The cellulose fiber (B) may be a staple fiber or a long fiber, and it is possible to select which one is to be used, as appropriate, depending on the type of flame-blocking fabric and the like. Although the single fiber fineness is selected as appropriate depending on the application of a fiber complex in which the cellulose fiber (B) is used, the single fiber fineness may be 1 dtex or more and 50 dtex or less, 1.5 dtex or more and 30 dtex or less, or 1.7 dtex or more and 15 dtex or less. The cut length is selected as appropriate depending on the type of flame-blocking fabric. For example, a short-cut fiber (with a fiber length of 0.1 mm or more and 5 mm or less), a staple fiber (with a fiber length of 6 mm or more and 128 mm or less), or a long fiber (filament) that is not cut at all can be used. For spinning, the cut length of the cellulose fiber (B) may be 32 mm or more and 128 mm or less, or 38 mm or more and 76 mm or less.
The flame-retardant upholstered furniture includes an inner structure and a flame-blocking fabric, and has excellent flame-blocking properties (flame retardancy) due to the flame-blocking fabric cover the inner structure.
Examples of the upholstered furniture include chairs such as a sofa and a couch. The chairs may include an elastic body such as a spring, an inner structure such as a urethane foam or wadding, a wooden frame, and a fabric (including a flame-blocking fabric).
The spread of fire to the inner structure of the upholstered furniture can be reduced due to the flame-blocking fabric exhibiting the flame-blocking properties, and therefore, excellent flame retardancy as well as excellent texture and excellent feel can be imparted to upholstered furniture even when the upholstered furniture has any structure.
One or more embodiments of the way to use the flame-blocking fabric in upholstered furniture include wrapping the inner structure such as a urethane foam or wadding with the flame-blocking fabric. When the flame-blocking fabric is used as an inner fabric, specifically, when the flame-blocking fabric is located between the surface fabric and the inner structure, at least the outside of the inner structure at a portion where the surface fabric and the inner structure are in contact with each other is always covered by the flame-blocking fabric as an interliner (inner fabric), and the surface fabric (outer fabric) is provided on the outside of the flame-blocking fabric. The surface fabric is not particularly limited as long as the texture and the feel required for upholstered furniture are not impaired, and fabrics that are commonly used as the outer fabric of upholstered furniture can be used as appropriate. In addition, from the viewpoint of further improving the flame retardancy, the back surface of the surface fabric may be coated with a flame retardant to an extent that, for example, the texture is not impaired. It is preferable that the surface fabric is not coated with a flame retardant from the viewpoint of achieving favorable texture and feel.
The flame-retardant upholstered furniture has excellent flame retardancy and satisfies the following conditions: time until both afterflame and afterglow go out is 120 seconds or less after the end of the contact with flame when measured through the flammability test based on BS 5852: 2006. From the viewpoint of further improving the flame retardancy, the flame-retardant upholstered furniture may satisfy the following conditions: time until both afterflame and afterglow go out is 60 seconds or less after the end of the contact with flame when measured through the flammability test based on BS 5852: 2006.
Hereinafter, one or more embodiments of the present invention will be more specifically described byway of examples. Note that one or more embodiments of the present invention are not limited to the following examples. In the following description, “%” and “part(s)” mean “mass %” and “part(s) by mass”, respectively, unless otherwise stated.
The flame retardancy was evaluated based on BS 5852: 2006, which is the flame retardancy test standard for upholstered furniture in the United Kingdom. Based on the flame retardancy test standard for domestic chairs, the flame retardancy was measured as follows: a knitted fabric was sandwiched between a surface fabric and a urethane foam, the seat portion and the back portion of the urethane foam covered by the knitted fabric and the surface fabric were arranged so as to form a right angle, a flame-contact portion thereof was brought into contact with flame for 20 seconds using a burner (Ignition Source 1) supplying butane gas at a rate of 45 ml/minutes, and then time until both afterflame and afterglow went out (also referred to as “fire extinction time” hereinafter) was measured. The flame-blocking properties (flame retardancy) were evaluated based on the following criteria.
Sensory evaluation experts performed sensory evaluation of the softness of the flame-blocking fabric, and determined whether or not favorable texture was achieved.
Based on the results of the flame retardancy evaluation and the texture evaluation, whether or not the flame-blocking fabric was acceptable was determined.
Acceptable: The flame retardancy was determined as A or B, and the texture was favorable.
Unacceptable: The flame retardancy was determined as C, and/or the texture was poor.
A commercially available plain-woven fabric with a basis weight of about 250 g/m2 containing polyethylene terephthalate fibers in an amount of 100 mass % was used.
A surface fabric with a coating on the backside was used. A commercially available plain-woven fabric with a basis weight of about 250 g/m2 containing polyethylene terephthalate fibers in an amount of 100 mass % was subjected to back-coating processing using a processing liquid in accordance with Comparative Example 3 in Japanese Patent No. 5961684, and the resulting fabric was used. Specifically, the processing liquid was prepared by adding 30 parts by mass of a mixed solution containing zinc borate in an amount of 60 mass % and aluminum hydroxide in an amount of 40 mass %, and 5 parts by mass of a carboxymethyl cellulose thickener (70-mass % aqueous solution) to 100 parts by mass of a polyurethane resin emulsion containing a solid in an amount of 50 mass %, and the plain-woven fabric was coated with this processing liquid through doctor-knife coating. The adhesion amount of the solid in the processing liquid was set to 100 g/m2. In the drying process, pre-drying was performed at 80° C. for 5 minutes, and curing was performed at 150° C. for 1 minute.
An acrylonitrile copolymer containing acrylonitrile in an amount of 50 mass %, vinyl chloride in an amount of 49.5 mass %, and sodium p-styrene sulfonate in an amount of 0.5 mass % was obtained through emulsion polymerization using acrylonitrile, vinyl chloride, and sodium p-styrene sulfonate, and was then dissolved in dimethylformamide such that the acrylonitrile copolymer concentration was 30 mass %. 5 parts by mass of magnesium hydroxide subjected to silane coupling treatment (manufactured by Kyowa Chemical Industry Co., Ltd., product name “KISMA 5P”) was added with respect to 100 parts by mass of the acrylonitrile copolymer in the obtained the acrylonitrile copolymer solution, and thus a spinning solution was obtained. A dispersion liquid was prepared in advance by adding 30 mass % of the above-mentioned magnesium hydroxide to 100 mass % of dimethylformamide and uniformly dispersing the magnesium hydroxide, and this dispersion liquid was used as the magnesium hydroxide. In the dispersion liquid of the magnesium hydroxide, the average particle diameter of the magnesium hydroxide subjected to silane coupling treatment was 2 μm when measured through the laser diffraction method. The obtained spinning solution was extruded into a 50 wt % aqueous solution of dimethylformamide through a 300-hole nozzle with a nozzle hole diameter of 0.08 mm and was coagulated, followed by washing by water and drying at 120° C. The dried products were drawn to 3 times their original length, followed by heat treatment at 145° C. for 5 minutes. Thus, flame-retardant modacrylic fibers were obtained. The obtained flame-retardant modacrylic fibers had a single fiber fineness of 1.72 dtex, a strength of 2.7 cN/dtex, an elongation at break of 28%, and a cut length of 51 mm.
Flame-retardant modacrylic fibers were obtained using the same acrylonitrile copolymer as that in Production Example 1 in the same manner as in Production Example 1, except that 2 parts by mass of magnesium hydroxide subjected to silane coupling treatment (manufactured by Kyowa Chemical Industry Co., Ltd., product name “KISMA5P”) was added with respect to 100 parts by mass of the acrylonitrile copolymer in the solution of acrylonitrile copolymer. The obtained flame-retardant modacrylic fibers had a single fiber fineness of 1.7 dtex, a strength of 3.2 cN/dtex, an elongation at break of 30%, and a cut length of 51 mm.
Modacrylic fibers SB having a single fiber fineness of 1.7 dtex and a cut length of 51 mm (manufactured by Kaneka Corporation) were used as modacrylic fibers containing no flame retardant.
Spun yarns (cotton count No. 20/1) were produced using the modacrylic fibers shown in Table 1 below as the flame-retardant modacrylic fibers (A) and natural cotton fibers having a cut length of 31 mm or less as the cellulose fibers (B) and mixing the modacrylic fibers and the natural cotton fibers at ratios shown in Table 1 below. The spun yarns were knitted into a single knitted fabric with a basis weight of about 150 g/m2 using a flat-knitting machine SG122FC manufactured by Shima Seiki Mfg., Ltd.
A domestic chair model was assembled using the knitted fabric obtained as described above, the surface fabric 1, and a urethane foam in accordance with the method described in BS 5852: 2006. The domestic chair model was obtained by sandwiching the knitted fabric as the flame-blocking fabric (inner fabric) between the surface fabric 1 and the urethane foam and arranging the seat portion and the back portion of the urethane foam covered by the knitted fabric and the surface fabric 1 so as to form a right angle.
Flame-blocking fabrics and domestic chair models were produced in the same manner as in Example 1, except that modacrylic fibers shown in Table 1 below were used as the flame-retardant modacrylic fibers, and the modacrylic fibers and the natural cotton fibers were blended as shown in Table 1 below.
Flame-blocking fabrics and domestic chair models were produced in the same manner as in Example 1, except that modacrylic fibers shown in Table 1 below were used, and the modacrylic fibers and the natural cotton fibers were blended as shown in Table 1 below.
The flame retardancy and the texture of the domestic chair models of the examples and the comparative examples were evaluated as described above. Table 1 below shows the results.
It is clear from the results shown in Table 1 that the knitted fabrics of Examples 1 to 5 had excellent flame-blocking properties, thus making it possible to obtain upholstered furniture having excellent flame retardancy.
Meanwhile, in Comparative Example 1, the amount of the flame retardant in the knitted fabric was insufficient, and thus sufficient flame-blocking ability was not achieved.
In Comparative Example 2, the ratio of the cellulose fibers (B) in the knitted fabric was too low, and thus sufficient flame-blocking ability could not be achieved. In Comparative Example 3, the ratio of the cellulose fibers (B) in the knitted fabric was too high, and thus sufficient fire-extinction ability could not be achieved. In Comparative Example 4 in which the knitted fabric containing the modacrylic fibers with zinc oxide serving as a flame retardant was used and Comparative Example 5 in which the knitted fabric containing the modacrylic fibers with aluminum hydroxide serving as a flame retardant was used, the content of the flame retardant in the knitted fabric was 7.3 wt %, but sufficient flame-blocking ability could not be achieved.
In all of Examples 1 to 5 and Comparative Examples 1, 2, 4, and 5, the texture was good.
One or more embodiments of the present invention are not particularly limited, but may encompass at least the following embodiments.
[1] Flame-retardant upholstered furniture including: an inner structure; and a flame-blocking fabric that covers the inner structure,
[2] The flame-retardant upholstered furniture according to [1], wherein the flame-blocking fabric has a basis weight of 120 g/m2 or more and 220 g/m2 or less.
[3] The flame-retardant upholstered furniture according to [1] or [2], wherein the modacrylic fibers (A) containing an acrylonitrile copolymer that contains acrylonitrile in an amount of 30 mass % or more and 85 mass % or less, one or more halogen-containing monomers selected from the group consisting of a halogen-containing vinyl monomer and a halogen-containing vinylidene monomer in an amount of 15 mass % or more and 65 mass % or less, and a sulfonic group-containing monomer in an amount of 0 mass % or more and 3 mass % or less.
[4] The flame-retardant upholstered furniture according to [3], wherein the halogen-containing monomer is vinyl chloride.
[5] The flame-retardant upholstered furniture according to anyone of [1] to [4], wherein the flame-retardant modacrylic fibers (A) contain the magnesium compound inside the flame-retardant modacrylic fibers in an amount of 2 mass % or more and 15 mass % or less with respect to an overall mass of the flame-retardant modacrylic fibers.
[6] The flame-retardant upholstered furniture according to [5], wherein the magnesium compound has an average particle diameter of 0.3 μm or more.
[7] The flame-retardant upholstered furniture according to [5] or [6], wherein the magnesium compound is one or more selected from the group consisting of magnesium oxide and magnesium hydroxide.
[8] The flame-retardant upholstered furniture according to anyone of [1] to [7], wherein the cellulose fibers (B) are one or more of cellulose fibers selected from the group consisting of natural cellulose fibers and regenerated cellulose fibers.
[9] The flame-retardant upholstered furniture according to [8], wherein the natural cellulose fibers are natural cotton fibers.
[10] The flame-retardant upholstered furniture according to any one of [1] to [9], wherein the flame-blocking fabric is a knitted fabric.
[11] The flame-retardant upholstered furniture according to anyone of [1] to [10], further including a surface fabric, wherein the flame-blocking fabric is located between the inner structure and the surface fabric.
[12] The flame-retardant upholstered furniture according to [11], wherein the surface fabric is not coated with a flame retardant.
[13] The flame-retardant upholstered furniture according to any one of [1] to [12], wherein the inner structure is a urethane foam.
Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present disclosure. Accordingly, the scope of the invention should be limited only by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-162014 | Sep 2021 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2022/032104 | Aug 2022 | WO |
| Child | 18614317 | US |
