JP6730572B6 - Flame-retardant composite molding substrate, flame-retardant composite molding and method for producing the same - Google Patents

Description

The present invention relates to a base material which is reinforced with flame-retardant fibers and whose matrix component is a thermoplastic resin, which is used in the production of a fiber-reinforced composite molded article, and flame-retardant fibers which are reinforced and whose matrix component is a thermoplastic resin. The present invention relates to a flame-retardant composite molded article and a method for producing the same.

A composite molded article containing carbon fiber or glass fiber as a reinforcing fiber and having a thermosetting resin such as an epoxy resin as a matrix component has excellent mechanical properties and is lightweight, and thus is widely used in various applications. It is used. Further, as another type of composite molded body, a composite molded body in which the reinforcing fiber is a cellulosic fiber and the matrix component is a thermoplastic resin is also proposed. The cellulosic fiber/thermoplastic resin composite molded article is inferior in mechanical properties to the carbon fiber (or glass fiber)/thermosetting resin composite molded article, but 1) the matrix component is a thermoplastic resin. Therefore, the production time can be shortened. 2) Since the reinforcing fiber is of natural origin, there is an advantage that a product containing the reinforcing fiber can be proposed as a more environmentally friendly product.

As a cellulosic fiber/thermoplastic resin composite molded article, for example, Patent Document 1 discloses a cloth composed of one or two or more cellulosic fibers and one or two or more thermoplastic resin fibers as constituent materials. A composite molded article obtained by laminating at least one layer or two or more layers and molding at a temperature of at least the glass transition temperature or melting temperature of at least one thermoplastic resin fiber in the thermoplastic resin fiber, and having a predetermined linear expansion. Composite compacts having a modulus have been proposed. Patent Document 2 describes that a cellulose-based artificial fiber having an average diameter of 5 to 20 μm and a number-weighted average length of 200 to 800 μm is distributed in a thermoplastic polymer to prepare a composite material. ..

JP, 2014-95049, A Special table 2013-503980 gazette

Depending on the use of the composite molded body, the composite molded body may be required to have flame retardancy. In order to impart flame retardancy to the composite molded body, for example, Patent Document 1 describes that a flame retardant may be blended in the thermoplastic resin fiber. The present invention has been made for the purpose of obtaining a composite molded article that exhibits more excellent flame retardancy when a cellulosic fiber is used as a reinforcing fiber and a thermoplastic resin is used as a matrix.

In one aspect, the present invention provides a composite molding substrate containing regenerated cellulose fibers and a thermoplastic resin, wherein the regenerated cellulose fibers have a limiting oxygen index of 26 or more.
In another aspect of the present invention, there is provided a composite molded article containing regenerated cellulose fibers as reinforcing fibers and a thermoplastic resin as a matrix, wherein the regenerated cellulose fibers have a limiting oxygen index of 26 or more. Provide the body.
In another aspect, the present invention provides
Producing a composite molding substrate containing a regenerated cellulose fiber having a limiting oxygen index of 26 or more and a thermoplastic resin, and heating the composite molding substrate at a temperature at which the thermoplastic resin fiber melts or softens. There is provided a method for producing a composite molded body, which comprises:

The base material for composite molding of the present invention makes it possible to produce a composite molded article that exhibits the reinforcing effect of regenerated cellulose fibers and exhibits good flame retardancy, and the production of the composite molded article of the present invention using the same. The method is suitable for providing such composite shaped bodies. In addition, the composite molded article of the present invention exerts a reinforcing effect on the regenerated cellulose fiber and has good flame retardancy.

(Background of the invention)
As described above, in order to obtain a flame-retardant composite molded body, a method of incorporating a flame retardant into a component (a thermoplastic resin fiber in Patent Document 1) that serves as a matrix is often used. However, in order to achieve a predetermined flame retardancy (for example, V2 in UL94 standard), it is necessary to include a considerable amount of a flame retardant in the matrix component. When the flame retardant contains halogen, for example, the flame retardant itself may exert an environmental load, or the mechanical properties and processability of the composite molded body may be affected. Therefore, it is desirable to use as little flame retardant as possible.

Further, when cellulosic fibers are used as the reinforcing fibers, the flame retardancy of the composite molded article may not be improved even if the matrix contains a flame retardant. It is considered that this is because the cellulosic fibers themselves burn. Therefore, the present inventors have studied to improve the flame retardancy of the composite molded body by making the regenerated cellulose fiber flame retardant. Then, when the regenerated cellulose fiber containing the flame retardant is used, the amount of the flame retardant contained in the entire composite molded body is made considerably smaller than that in the case where the flame retardant is contained in the matrix component. Also found that a high flame retardant effect was obtained. Furthermore, the present inventors further improve the flame retardancy of the composite molded article when the regenerated cellulose fiber imparted with flame retardancy is used and the matrix component itself has self-extinguishing properties. Found.

Hereinafter, the reinforcing fiber, the thermoplastic resin, and the like, which constitute the composite molding base material and the composite molding of the present invention, will be described. Here, the "base material for composite molding" is a raw material for producing a composite molded body, and its mechanical properties and/or shape are changed by applying heat and pressure, so that the composite molded body is produced. Refers to something that gives. Examples of the composite molding base material include a fiber sheet containing regenerated cellulose fibers and thermoplastic resin fibers, and pellets in which the regenerated cellulose fibers are embedded in the thermoplastic resin.

(Regenerated cellulose fiber)
The base material for composite molding and the composite molded article of the present invention include regenerated cellulose fibers as reinforcing fibers. Regenerated cellulosic fiber refers to a fiber obtained by a method in which natural cellulose is treated with a chemical to dissolve it and then molded into a fiber shape. Specifically, viscose rayon, polynosic, cuprammonium rayon (including those sold under the trade name "Cupra"), acetate, solvent-spun cellulose fiber (sold under the trade names "TENCEL" and "Lyocell"). And the like) are included as the regenerated cellulose fiber. Viscose rayon is preferably used in the present invention. As for viscose rayon, a flame-retardant one is commercially available, or in addition to the fact that flame-retardant can be easily imparted by adding a flame-retardant to viscose, fine fold-like irregularities are formed on the peripheral surface of the fiber. And has a large contact area with the thermoplastic resin and easily exhibits high interfacial strength with the thermoplastic resin, and thus is preferably used. However, the mechanical properties (such as tensile strength and bending strength) of the composite molded body tend to improve as the single fiber strength of the reinforcing fiber increases, so from the viewpoint of the reinforcing effect, polynosic and solvent-spun cellulose are used. Fibers are also preferably used.

The fineness of the regenerated cellulose fiber used in the present invention is not particularly limited, and may be, for example, 0.1 dtex or more and 22 dtex or less, preferably 1.0 dtex or more and 10 dtex or less, and more preferably 1.4 dtex to It has a fineness of 8.0 dtex. The smaller the fineness of the reinforcing fibers, the more the reinforcing fibers are present in the composite molded body when the fibers having the same mass are contained in the composite molded body, that is, the more the number of the reinforcing fibers contained in the composite molded body is. The larger the amount, the greater the reinforcing effect. However, it is difficult to obtain a regenerated cellulose fiber having a fineness of less than 0.1 dtex. Further, since such thin regenerated cellulose fibers are difficult to handle, when the composite molded body is manufactured by a method including manufacturing a fiber sheet together with the thermoplastic resin fiber, the production efficiency of the composite molded body is lowered. In the present invention, two or more kinds of regenerated cellulose fibers having different fineness may be used.

The fiber length of the regenerated cellulose fiber used in the present invention is also not particularly limited. For example, the fiber length may be 1 mm or more. The composite molded body may intentionally or unavoidably contain a plurality of regenerated cellulose fibers having different fiber lengths. In one embodiment, the regenerated cellulose fibers all have substantially the same fiber length. Regenerated cellulose fibers of finite length are produced by a method in which after spinning, the fibers are cut by a cutting machine so as to have the same fiber length, so when using commercially available regenerated cellulose fibers having a predetermined fiber length, The fibers having the same fiber length can be present in the composite molded body.

The longer the fiber length of the reinforcing fiber, the better the reinforcing effect. Therefore, when the fiber length of the regenerated cellulose fiber is too short (for example, less than 1 mm), it is difficult to obtain a sufficient reinforcing effect. In particular, since fibers having a fiber length of less than 1 mm are in a powder form, when a composite molded body is produced by a method including producing a fiber sheet together with a thermoplastic resin fiber, regenerated cellulose fibers may fall off from the fiber sheet. Inconvenience may occur.

When a composite molded body is manufactured by a method including manufacturing a fiber sheet as a composite molding base material from a reinforcing fiber and a thermoplastic resin fiber, the fiber length of the regenerated cellulose fiber depends on the form of the fiber sheet to be manufactured. different. For example, when producing a card web to produce a fiber sheet in the form of a non-woven fabric, the fiber length of the regenerated cellulose fiber is preferably 20 mm to 70 mm, more preferably 25 mm to 52 mm. When producing an air-laid web or a wet papermaking web to produce a fiber sheet in the form of a nonwoven fabric, the fiber length of the regenerated cellulose fibers is preferably 3 mm to 25 mm, more preferably 5 mm to 20 mm. Alternatively, the fibrous sheet does not have to be configured using fibers having a finite length, and may be, for example, a long-fiber non-woven fabric such as a spun-bonded non-woven fabric, or a woven or knitted fabric of filament yarn.

When the composite molding substrate is provided in the form of pellets, regenerated cellulose fibers having a fiber length of, for example, 1 mm to 3 mm may be irregularly dispersed in the pellets. Alternatively, when the pellet is manufactured by a method of impregnating a bundle of reinforcing fibers with a molten thermoplastic resin, solidifying the resin to obtain a rod-shaped object, and then cutting it into a predetermined length, in the pellet, The regenerated cellulose fiber is oriented in the length direction of the pellet and has a fiber length equal to the length of the pellet (usually 1 mm or more, for example, 2 mm to 15 mm).

The regenerated cellulosic fibers may be in the form of hollow fibers having cavities therein which extend along the length of the fibers. When the regenerated cellulose fiber is a hollow fiber, a bubble portion is present in the finally obtained composite molded article, and the heat insulating property and the sound absorbing property of the composite molded article can be improved.

The regenerated cellulosic fiber may have a flat cross section and have a tape-like appearance. If the cross-sectional shape is flat, the interfacial strength between the regenerated cellulose fiber and the thermoplastic resin (matrix) tends to increase, and the mechanical properties of the composite molded body can be further improved.

The regenerated cellulose fiber used in the present invention has flame retardancy imparted by a flame retardant or the like so as to have a limiting oxygen index of 26 or more, and preferably has a limiting oxygen index of 28 or more, more preferably 30 or more. Have. Here, the limiting oxygen index (also referred to as LOI value) refers to the minimum oxygen concentration (volume %) required for sustaining the combustion of a material, which is measured according to JIS L 1091 E method (oxygen index method test). It can be said that the flame retardancy is high. The shape of the test piece is No. E-1. Further, in the present specification, "flame retardant" comprehensively refers to the property that an object is difficult to burn, and is used in a meaning including "self-extinguishing", "retardant" and "non-flammable".

The regenerated cellulose fiber having the above-mentioned limiting oxygen index (hereinafter referred to as “flame-retardant regenerated cellulose fiber”) is obtained, for example, by containing a flame retardant. The flame retardant is, for example, an aromatic phosphoric acid ester, an aromatic condensed phosphoric acid ester, a halogen-containing phosphoric acid ester, a halogen-containing condensed phosphoric acid ester, and a phosphorus-based flame retardant such as red phosphorus, or a phosphorus-based flame retardant. It is possible to use a flame retardant as a main component in combination with a halogen-based flame retardant or an inorganic flame retardant. Preferred flame retardants are aromatic phosphates. The regenerated cellulose fiber containing the flame retardant may be produced by a method of spinning a spinning solution containing the flame retardant. Alternatively, the flame-retardant regenerated cellulose fiber may be obtained by a method of attaching a flame retardant to the fiber surface.

When the flame-retardant regenerated cellulose fiber contains a flame retardant, its limiting oxygen index is determined by the type and content of the flame retardant. For example, when a phosphorus-based flame retardant is used as the flame retardant, if the content of the phosphorus-based flame retardant is about 1% by mass to 10% by mass with respect to the mass of the entire fiber, the above-described predetermined limiting oxygen index can be obtained. Since the mechanical properties of the regenerated cellulose fiber tend to decrease as the content of the flame retardant increases, it is preferable to reduce the content of the flame retardant as much as possible from the viewpoint of the reinforcing effect.

The reason why the flame retardancy of the composite molded article is improved when the flame-retardant regenerated cellulose fiber is used is considered that the reinforcing fiber also functions as a flame retardant for the matrix component. That is, by making the reinforcing fiber flame-retardant, not only the reinforcing fiber itself becomes difficult to burn, but also the matrix in which the fiber is dispersed becomes difficult to burn, and the flame-retardant property of the composite molded body is enhanced. It is presumed that there is.

The regenerated cellulosic fiber optionally contains other components, for example, one or more additives selected from ultraviolet absorbers, charcoal, pigments, deodorants, antibacterial agents, minerals such as zeolites, and the like. You may Depending on the type of additive, the additive contained in the regenerated cellulose fiber may impart a predetermined function to the composite molded body or may improve the function of the composite molded body.

(Thermoplastic resin)
The thermoplastic resin serves as a matrix in the composite molded body. The thermoplastic resin is melted or softened by heating, can be processed into a desired shape in that state, and is solidified by cooling after processing. The time from the melting or softening of the thermoplastic resin to the solidification thereof is shorter than the time required to solidify the thermosetting resin (the time from once the fluidity of the thermosetting resin becomes high to the time of hardening). Further, unlike the thermosetting resin, the thermoplastic resin can be re-molded by applying heat even after it has been molded once. Therefore, by using a thermoplastic resin as a matrix, a composite molded body can be manufactured with high production efficiency, and a composite molded body excellent in processability can be obtained.

The thermoplastic resin is not particularly limited. Examples of the thermoplastic resin include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, and polybutylene succinate; low density polyethylene, medium density polyethylene, high density polyethylene, linear chain. Low density polyethylene, and ultra-high molecular weight polyethylene, such as polyethylene polymerized using ordinary Ziegler-Natta catalysts and metallocene catalysts, isotactic polymerized using ordinary Ziegler-Natta catalysts and metallocene catalysts, Polypropylene such as atactic and syndiotactic, polymethylpentene, polybutene-1, ethylene-vinyl alcohol copolymer, and various polyolefins such as ethylene-propylene copolymer; nylon 6, nylon 66, nylon 11 and nylon 12 And the like; engineering plastics such as polycarbonates, polyacetals, polystyrenes, and cyclic polyolefins; and super engineering plastics such as polyetherimides and polyimides. The thermoplastic resin may be the above-listed resins modified with an acid or the like, or may be a copolymer resin.

It is known that some of these resins can be produced from plant-derived raw materials. For example, polylactic acid can be produced using potato, corn, sugar cane, etc. as raw materials. In addition, polyethylene called biopolyethylene, polypropylene called biopolypropylene, and polycarbonate called biopolycarbonate, which are produced from plant-derived raw materials such as sugar cane, have also been proposed. When these plant-derived thermoplastic resins are used, the composite molded article of the present invention can be provided as an environmentally friendly product in combination with the fact that the regenerated cellulose fibers are plant-derived.

As the thermoplastic resin, those having self-extinguishing property are preferably used. "Self-extinguishing" refers to the property of burning while exposed to a flame, but extinguishing when separated from the flame. Specifically, in the method A specified by JIS K6911, the test piece burns out within 180 seconds after removing the flame, and has a self-extinguishing property when the burned length is 25 mm or more and 100 mm or less. Defined as a thing.

Some thermoplastic resins exhibit flame retardancy called "slow flame retardance" (a property in which combustion continues even after being separated from the flame, but the combustion speed is slow), but in the present invention, self-extinguishing A thermoplastic resin having properties is preferably used. This is because the flame retardancy-enhancing effect of the flame-retardant regenerated cellulose fiber is more remarkably exhibited for the thermoplastic resin having self-extinguishing property.

The limiting oxygen index of the thermoplastic resin having self-extinguishing property is preferably 25 or more, more preferably 26 or more, and even more preferably 28 or more. The higher the limiting oxygen index, the higher the self-extinguishing property, and the combination with the flame-retardant regenerated cellulose fiber imparts the higher flame retardancy to the composite molded body. However, if the limiting oxygen index exceeds 25, the thermoplastic resin itself becomes extremely inflammable, so it is not possible to obtain the effect of further improving the flame retardancy by applying flame-retardant regenerated cellulose. It gets harder.

The self-extinguishing property is preferably obtained by forming a carbonized layer on the surface of the thermoplastic resin by combustion and preventing the carbonized layer from further combustion. As the thermoplastic resin having self-extinguishing property, there is another one in which an intimate flame retardant (which exhibits an effect of delaying combustion by forming a heat insulating foam layer during combustion) is added. You may use such a thermoplastic resin. However, when a self-extinguishing thermoplastic resin that does not form a carbonized layer is used, the effect of adding flame-retardant regenerated cellulose tends to be difficult to obtain.

The self-extinguishing thermoplastic resin may be intrinsically self-extinguishing, or may be made self-extinguishing by adding a flame retardant or the like. In the present invention, a thermoplastic resin inherently having self-extinguishing property, that is, a thermoplastic resin having self-extinguishing property without adding a flame retardant is preferably used. Such thermoplastics are, for example, polycarbonate (PC), polyetherimide (PEI), polyphenylene ether (PPE).

The thermoplastic resin having inherent self-extinguishing property may contain a flame retardant or the like. In that case, the self-extinguishing property of the thermoplastic resin is further enhanced, and the flame retardancy of the composite molded body is further improved. When the thermoplastic resin contains a flame retardant, its content is preferably 5% or less of the total mass of the flame retardant and the thermoplastic resin.

Since the thermoplastic resin becomes self-extinguishing by adding a flame retardant depending on the type of resin, any of the resins listed above can be used in the present invention by adding a flame retardant. When a thermoplastic resin containing a flame retardant is used in the present invention, the proportion of the flame retardant in the entire composite molded article can be reduced as compared to the case where the flame retardant regenerated cellulose fiber is not used.

The flame retardant is selected from halogen flame retardants, phosphorus flame retardants, inorganic flame retardants, and silicone flame retardants. More specifically, the flame retardant is selected from, for example, aromatic condensed phosphoric acid ester, a mixture of aromatic phosphonic acid ester and an organic nitrogen compound. Alternatively, the flame retardant may be an intumescent flame retardant. When the thermoplastic resin is polycarbonate, it is preferable to use, for example, an aromatic condensed phosphoric acid ester as the flame retardant.

The self-extinguishing thermoplastic resin may be used in combination with a self-extinguishing thermoplastic resin. For example, polycarbonate may be used in combination with polylactic acid. However, the flame retardancy-enhancing effect of the flame-retardant regenerated cellulose fiber is less likely to be exerted on a thermoplastic resin that does not have self-extinguishing properties, and when such a combination is used, the flame retardancy of the resulting composite molded article is improved. Is lower than that when only a thermoplastic resin having self-extinguishing property is used.

The thermoplastic resin may be in any form before it anchors the reinforcing fibers as a matrix. Therefore, the thermoplastic resin may be, for example, in the form of fibers, or in the form of pellets or powder, which is melted or softened and then solidified to form the matrix of the composite molded body. ..

The thermoplastic resin may optionally contain one or more additives selected from pigments, hydrophilizing agents, antibacterial agents, antifungal agents, fillers, abrasives, lubricants and the like. When the additive is included, the proportion thereof is preferably 30% or less of the total mass of the additive and the thermoplastic resin (or the total mass of the flame retardant when it is included). Like the additive of the regenerated cellulose fiber, the additive added to the resin can also impart a predetermined function to the composite molded body or can improve the function of the composite molded body.

(Thermoplastic resin fiber)
The base material for composite molding of the present invention can be provided in the form of a fiber sheet (hereinafter, also referred to as “sheet base material for composite molding” or “sheet base material”) containing a thermoplastic resin in the form of fibers. The thermoplastic resin fiber constituting the sheet base material has a fineness and a fiber length selected according to the form of the sheet base material, as described later. The smaller the fineness of the thermoplastic resin fiber, the more easily the thermoplastic resin penetrates into the regenerated cellulose when it is melted or softened. On the other hand, fibers having a small fineness have poor handleability, which may reduce the production efficiency of spun yarn or nonwoven fabric. Therefore, the fineness of the thermoplastic resin fiber is appropriately determined in consideration of the permeability between the regenerated cellulose fibers and the manufacturability of the sheet base material (including the manufacturability of the spun yarn and the like used for manufacturing the sheet base material). To be selected.

The thermoplastic resin fibers may have a fineness of 0.5 dtex to 50 dtex and a fiber length of 1 mm to 100 mm. A preferred fineness is 1 dtex to 20 dtex. When a composite molded body is manufactured by a method including manufacturing a fiber sheet as a base material for composite molding from a reinforcing fiber and a thermoplastic resin fiber, the fiber length of the thermoplastic resin fiber depends on the form of the fiber sheet to be manufactured. different. For example, in the case of producing a card web to produce a fiber sheet in the form of a nonwoven fabric, the fiber length of the thermoplastic resin fiber is preferably 30 mm to 70 mm, more preferably 40 mm to 60 mm. When producing an air-laid web or a wet papermaking web to produce a fiber sheet in the form of a non-woven fabric, the fiber length of the thermoplastic resin fibers is preferably 2 mm to 10 mm, more preferably 4 mm to 6 mm. It is difficult to form a thin fiber from a thermoplastic resin depending on its melt viscosity, and for example, when polycarbonate is used, it is generally difficult to set the fineness to 1.0 dtex or less. When a sheet base material is produced using fibers made of such a thermoplastic resin, the fineness thereof is selected in consideration of the production efficiency of the thermoplastic resin fibers (for example, melt spinnability of the resin).

The thermoplastic resin fiber may be a composite fiber composed of two or more components. The composite form of the composite fiber is not particularly limited, and may be, for example, a core-sheath type, a side-by-side type, a split type in which two components are alternately arranged in a chrysanthemum pattern in the fiber cross section, or a sea-island type. When the composite fiber is used, in the composite molded body in which the matrix is composed of two or more thermoplastic resins, a matrix in which the thermoplastic resins are uniformly mixed can be easily obtained.
Alternatively, the thermoplastic fiber may be a single fiber, or a composite fiber, or in the form of a hollow fiber.

(Base material for composite molding)
The base material for composite molding of the present invention contains the regenerated cellulose fiber having the specific limiting oxygen index described above and the thermoplastic resin described above. The base material for composite molding is provided as a fiber sheet when it contains a thermoplastic resin as fibers. The base material in the form of a fiber sheet will be described later.

The composite molding substrate may be in the form of pellets. The pellet is used as a raw material supplied to a molding machine for manufacturing a composite molded body, and has, for example, a rectangular shape, a cubic shape, a gostone shape, a column shape, or an elliptic column shape. As mentioned above, in the pellet, the regenerated cellulose fibers may be randomly dispersed or oriented in a certain direction. Pellets can be produced by mixing regenerated cellulose fibers and a non-fibrous thermoplastic resin by a usual pellet production method. Alternatively, the pellets may be manufactured by a method in which a bundle of reinforcing fibers is impregnated with a molten thermoplastic resin as described above, the resin is solidified to obtain a rod-shaped product, and then cut into a predetermined length. it can.

(Sheet base material for composite molding)
The composite molding sheet base material of the present invention is a fiber sheet containing regenerated cellulose fibers having the above specific limiting oxygen index and fibers made of a thermoplastic resin. When this sheet base material is heated, only the thermoplastic resin fibers are melted or softened, penetrated between the regenerated cellulose fibers, and then cooled to solidify to become a matrix for fixing the fibers.

The sheet substrate can be, for example, a woven, knitted, or non-woven fabric, or a combination thereof. Further, the sheet base material may be in the form of a laminate of a sheet made of thermoplastic resin fibers and a sheet made of regenerated cellulose fibers, in which case the sheets to be laminated may have the same form and are different from each other. You can stay. For example, the sheet base material may be formed by laminating a nonwoven fabric made of thermoplastic resin fibers on a woven fabric made of regenerated cellulose fibers and integrating them.

When the sheet base material is a woven or knitted fabric, the yarn constituting the woven fabric may be any of a mixed yarn, a mixed yarn, a core yarn, and a covered yarn made of regenerated cellulose fibers and thermoplastic resin fibers. The core yarn and the covered yarn may be a filament yarn composed of a continuous fiber of regenerated cellulose and a short fiber of a thermoplastic resin wound around the core yarn, or a core yarn made of a continuous fiber of a thermoplastic resin fiber. The filament yarn may be a filament yarn around which short fibers of regenerated cellulose fiber are wound. Alternatively, the woven fabric may be produced by using one of the warp yarn and the weft yarn as a yarn made of regenerated cellulose fiber and the other as a yarn made of thermoplastic resin fiber. The knitted fabric may also be a knitted fabric of two types of yarns, that is, a yarn made of regenerated cellulose fiber and a yarn made of thermoplastic resin fiber. The structure of the woven or knitted material that constitutes the sheet base material is not particularly limited, and may be a commonly used structure. The woven and knitted fabrics may be multi-woven and multi-woven, respectively.

When the sheet base material is a woven or knitted fabric, the fineness and the fiber length of the constituent fibers are selected according to the type of yarn constituting the woven or knitted fabric. For example, when a spun yarn is produced from staple fibers having a staple length, fibers having a fineness of 1 dtex to 30 dtex and a fiber length of 30 mm to 70 mm are generally used. Therefore, from these ranges, regenerated cellulose fibers and thermoplastic resin fibers can be used. The fineness and the fiber length may be selected respectively.

If the sheet substrate is a woven or knitted, basis weight of the woven or knitted fabric, depending on the thickness or the like of the composite molded body to be obtained, for example as good as ^{400g / m 2 ~12000g / m 2} , particularly 500 g / m It may be ^{2 to} 3600 g/m ² . The basis weight of the woven or knitted fabric is adjusted by appropriately selecting the yarn count and the density of the warp and the weft.

In the present invention, the sheet base material is preferably a non-woven fabric. The non-woven fabric can be manufactured by a method in which it is relatively easy to uniformly mix two or more kinds of fibers in a desired ratio.
When the sheet base material is a non-woven fabric, the non-woven fabric is produced by producing a fibrous web using regenerated cellulose fibers and thermoplastic resin fibers, and then adhering and/or interlacing the fibers to integrate them. The form of the fibrous web is not particularly limited and may be any form selected from a parallel web, a cross web, a card web such as a semi-random web and a random web, an air-laid web, a wet paper making web, and a spunbond web. Good.

In the production of the nonwoven fabric, the method of integrating the fibers of the fibrous web is not particularly limited. For example, the fibers may be integrated by a mechanical entanglement method such as a needle punch method and a hydroentanglement treatment method. Alternatively, when the thermoplastic resin fiber is a composite fiber composed of two or more components, and one component exhibits thermal adhesiveness at a temperature lower than the temperature at which the regenerated cellulose fiber decomposes, the fibers are separated by the component. The fibers may be united by heat bonding.

The fineness and fiber length of the fibers constituting the nonwoven fabric are selected according to the form of the fibrous web and the like. The preferred range of the fiber length of the regenerated cellulose fiber and the thermoplastic resin fiber when the sheet base material is in the form of a nonwoven fabric is as described above. In making either fibrous web, the fiber length of the regenerated cellulose fibers may be the same as or different from that of the thermoplastic resin fibers.
In any case of producing any fibrous web, the fineness of the regenerated cellulose fiber may be, for example, 0.1 dtex to 20 dtex. The fineness of the thermoplastic resin fiber may be, for example, 0.5 dtex to 50 dtex.

The non-woven fabric may be a laminate of two or more fibrous webs. In that case, one or a plurality of fibrous webs may be made of regenerated cellulose fibers and another one or a plurality of fibrous webs may be made of thermoplastic resin fibers. The two or more fibrous webs may be made by the same method or may be made by different methods (eg, a combination of card web and wet papermaking web).

If the sheet substrate and the nonwoven fabric, the basis weight of the nonwoven fabric, depending on the thickness and the like of the composite structure to be obtained, for example as good as ^{400g / m 2 ~12000g / m 2} , especially 500g ^/ m 2 ~3600g ^/ m ² can be used. In order to increase the basis weight of the nonwoven fabric, two or more same or different fiber webs may be laminated and subjected to a treatment for integrating the fibers (for example, a fiber entanglement treatment such as needle punching).

The mixing ratio (mass ratio) of the regenerated cellulose fiber and the thermoplastic resin fiber is 20:80 to 60:40 (regenerated cellulose fiber:thermoplastic resin fiber) regardless of the type of the fiber sheet serving as the sheet base material. Is preferred. More preferably, it is 30:70 to 50:50. If the proportion of regenerated cellulose fibers is too low, the effect of reinforcement by regenerated cellulose fibers may not be sufficiently obtained. If the proportion of the regenerated cellulose fibers is too large, the thermoplastic resin may not sufficiently penetrate between the regenerated cellulose fibers, and the mechanical strength of the composite molded article may be significantly reduced.

The sheet base material may include fibers (hereinafter, also referred to as “third fibers”) other than regenerated cellulose fibers and thermoplastic resin fibers. For example, the sheet substrate includes, as the third fiber, a reinforcing fiber other than regenerated cellulose fiber, such as carbon fiber, glass fiber, or aramid fiber, or other cellulosic fiber (eg, cotton, bamboo linen, etc.). You can go out. The mixing ratio of the third fiber is, for example, 30% by mass or less, and preferably 20% by mass or less, of the entire sheet base material. These third fibers may also be included in substrates that are not sheet substrates, for example substrates in the form of pellets.

The sheet base material may be a laminated sheet including a fiber sheet and another sheet-like material. The other sheet-like material is, for example, a film or a net made of a thermoplastic resin. The other sheet-like material may be made of, for example, a thermoplastic resin that is difficult to form into a fiber, and in that case, it is easier to obtain a composite molded body containing such a thermoplastic resin as a matrix. Becomes

(Composite molding)
It can be said that the composite molded article of the present invention is a fiber-reinforced composite molded article in which the thermoplastic resin is the matrix and is reinforced with regenerated cellulose fibers. The physical property reinforced by the fiber is at least one of mechanical properties selected from tensile strength, bending strength, impact strength (particularly Charpy impact value) and the like. The composite molded body in which at least one improvement in mechanical properties is recognized by the addition of the regenerated cellulose fiber is a fiber reinforced composite molded body.

The composite molded article of the present invention is provided as, for example, a sheet-like article or a three-dimensional structure molded into a predetermined shape.

The thickness and basis weight of the sheet-like composite formed body is appropriately selected depending on the application or the like, not particularly limited, for example, the thickness of the 0.3Mm～10mm, and 400g ^{/ m 2} ~12000g ^/ m 2 Have a fabric weight. A sheet-shaped composite molded body containing a thermoplastic resin as a matrix can be provided as a stampable sheet that can be molded into another shape by heating and pressing. Forming a stampable sheet is sometimes called stamping forming.

The sheet-shaped composite molded article may be one produced from the above-mentioned sheet base material, or a mixture of regenerated cellulose fibers and thermoplastic resin pellets or powdery material, and formed into a sheet-like shape using a molding machine. It may be manufactured by the manufacturing method. When a composite molded body is manufactured from a sheet base material, the thermoplastic resin fiber does not completely melt depending on the temperature and pressure applied to the thermoplastic resin fiber, and the thermoplastic resin fiber in the composite molded body changes its fiber shape. It may exist in a state of being maintained to some extent. In particular, as will be described later, when the thermoplastic resin has a high melting point and is heated at a temperature higher than the melting point, when the regenerated cellulose fiber is decomposed, the thermoplastic resin is processed at a temperature lower than the melting point, The fiber shape tends to be more maintained.

The composite molded product in which the thermoplastic resin fibers are not completely melted is a composite molded product in which the thermoplastic resin is completely melted and solidified because the voids between the regenerated cellulose fibers are not completely filled with the thermoplastic resin. It is increased to specific volume compared to, specifically, for example, 1.1cm ³ /g~2.0cm ³ / g, in particular has a 1.2cm ³ /g~1.5cm ³ / g approximately specific volume obtain. The composite molded article in which the thermoplastic resin fibers are not completely melted has a structure in which the melted portion of the thermoplastic resin fibers serves as the skeleton and voids between the fibers are held to some extent. The composite molded article having such a structure may exhibit sound absorption and/or impact absorption due to the voids. Further, such a composite molded article has a surface that is not smooth as compared with a composite molded article in which the thermoplastic resin is completely melted and solidified, and has a rough tactile sensation derived from the sheet base material, or Fiber fluff is observed at. Since the composite molded article of the present invention contains regenerated cellulose fibers having water absorption itself, the degree of melting of the thermoplastic resin fibers is higher, for example, even when the thermoplastic resin fibers are completely melted and then solidified, composite molding is performed. The body absorbs water to some extent.

Including one or more kinds of thermoplastic resin, if their melting points are different from each other, in a composite molded article produced from a sheet substrate, one or more kinds of thermoplastic resin fibers are melted, and the fiber shape is lost, The shape of other thermoplastic resin fibers may remain. For example, when using a sheet substrate containing a polycarbonate fiber and a polylactic acid fiber as a thermoplastic resin fiber, the polylactic acid is more likely to lose its fiber shape because the melting point of the polylactic acid is lower, and the polycarbonate fiber has a relatively smaller shape. Tends to hold.

The composite molded article of the present invention is generally provided as a three-dimensional structure processed into a predetermined shape. The three-dimensional structure is, for example, one formed by a molding machine using the pellets, three-dimensionally formed when the sheet base material is heated, or the sheet-shaped composite formed body (stampable sheet). 3) is three-dimensionally molded, or regenerated cellulose fibers and thermoplastic resin pellets or powders are mixed and molded by a molding machine. Alternatively, the three-dimensional structure may be formed by cutting a block of the composite molded body into a predetermined shape.

In any of the forms, the composite molded article of the present invention contains regenerated cellulose fibers as reinforcing fibers in a proportion of 20% by mass to 60% by mass with respect to the total mass of the regenerated cellulose fibers and the thermoplastic resin. Good. It is preferably 30% by mass to 50% by mass. Composite shaped bodies containing regenerated cellulose fibers in such proportions have excellent mechanical properties. Further, when the proportion of the regenerated cellulose fibers is in that range, it is easy to obtain a composite molded body in which the regenerated cellulose fibers are uniformly dispersed in the composite molded body.

(Method for manufacturing composite molded body)
The composite molded article of the present invention is to produce a composite molding base material containing a regenerated cellulose fiber having a specific limiting oxygen index and a thermoplastic resin, and the thermoplastic resin melts or softens the composite molding base material. It is manufactured by a manufacturing method including heating at a temperature. Here, as one form of the manufacturing method, a manufacturing method using the sheet base material will be described. This embodiment includes producing a sheet base material and heating the sheet base material at a temperature at which the thermoplastic resin fibers melt or soften.
A sheet base material in the form of a woven fabric or a knitted fabric can be produced by weaving or knitting a blended yarn of regenerated cellulose fibers and thermoplastic resin fibers by a usual method.

A sheet substrate in the form of a non-woven fabric is produced by making a fibrous web and adhering and/or interlacing and integrating the fibers in the fibrous web. When the thermoplastic resin fibers have thermal adhesiveness, the fibers can be bonded by a hot air through heat treatment machine (also called an air through heat processing machine), a hot air blowing heat treatment machine, an infrared heat treatment machine, or a hot roll processing. You may carry out using a machine. The thermal bonding with fibers is carried out at a temperature at which the thermoplastic resin melts or softens but the regenerated cellulose fibers do not decompose. However, if the thermoplastic resin fibers are heat-bonded, the sheet base material becomes too hard to be wound up on a roll, and it becomes difficult to handle as a sheet base material. Pay attention to the heating time. Alternatively, the fibers may be bonded by using an adhesive or the like.

When the fibers are entangled, a hydroentanglement treatment method or a needle punch method is used. In this embodiment, the needle punch method is preferably used. According to the needle punch method, even when relatively large and the fiber web having a basis weight of, for example, 400g / m ² ~12000g / m ² approximately, capable of relatively easily entangled fibers. The needle punching treatment of the fiber web having a weight per unit area in this range is, for example, a 36-42 count needle having a barb number of 3-9, a needle depth of 3-20 mm, and 10-500. It may be performed by implanting at a density of books/cm ² .

Next, the sheet base material is subjected to heat treatment to melt or soften the thermoplastic resin so that the resin permeates between the regenerated cellulose fibers. The heat treatment may be accompanied by a pressure treatment. In particular, when the melting point of the thermoplastic resin is high and/or the melt viscosity of the thermoplastic resin is high, the pressure treatment is simultaneously performed to further promote the penetration of the thermoplastic resin between the regenerated cellulose fibers. To be done.

The heating is performed at a temperature at which the thermoplastic resin melts or softens. If the heating temperature is set higher than the melting point of the thermoplastic resin, it becomes easier for the thermoplastic resin to penetrate between the regenerated cellulose fibers, but when the heating temperature exceeds the decomposition temperature of the regenerated cellulose fibers, the regenerated cellulose fibers deteriorate, The reinforcing effect of regenerated cellulose fibers may not be obtained. In that case, it is preferable that the heating temperature be lower than the melting point of the thermoplastic resin and the pressure treatment be performed. When two or more types of thermoplastic resin fibers are used, heat treatment is performed at a temperature at which at least one type of thermoplastic resin is melted or softened.

When the heating temperature is lower than the melting point of the thermoplastic resin, it is preferable that the heating temperature is equal to or higher than the glass transition temperature of the thermoplastic resin. When heating at a temperature higher than the glass transition temperature, a pressure treatment is carried out to reduce the damage to the regenerated cellulose fiber, and the regenerated cellulose fiber can be fixed by the thermoplastic resin. When the glass transition temperature of the thermoplastic resin is higher than the decomposition temperature of the regenerated cellulose fiber and/or when the penetration of the thermoplastic resin into the regenerated cellulose fiber is ensured by the pressure treatment, the heating temperature is set to the glass transition temperature. It may be lower than the temperature. When it is desired to maintain the shape of the thermoplastic resin fibers to some extent in the obtained composite molded article, a heating temperature lower than the melting point of the thermoplastic resin may be selected. When it is desired to maintain the shape of the thermoplastic resin fiber, the pressure during the pressure treatment may be lowered.

For example, when using a polycarbonate fiber having a glass transition temperature of 70°C to 170°C as the thermoplastic resin fiber, the heating temperature is preferably 150°C to 250°C. More preferably, the heating temperature is 150°C to 210°C in order to suppress decomposition of the regenerated cellulose fiber. When the heating temperature is within this range, pressure treatment is performed. The pressure treatment is performed by applying a pressure of 1 MPa to 10 MPa, for example. When polylactic acid fiber having a melting point of about 150°C to 200°C is used as the thermoplastic resin fiber, the heating temperature is preferably 150°C to 250°C. More preferably, the heating temperature is 150°C to 210°C in order to suppress decomposition of the regenerated cellulose fiber. When the pressure treatment is performed in addition to the heat treatment, the pressure is preferably 1 MPa to 10 MPa. When polypropylene fibers having a melting point of about 160° C. to 170° C. are used as the thermoplastic resin fibers, the heating temperature is preferably 170° C. to 210° C. When the pressure treatment is performed in addition to the heat treatment, the pressure is preferably 1 MPa to 10 MPa.

When a modified polypropylene fiber having a melting point of 140°C to 160°C is used as the thermoplastic resin fiber, the heating temperature is preferably 150°C to 200°C. When the pressure treatment is performed in addition to the heat treatment, the pressure is preferably 1 MPa to 10 MPa. When polymethylpentene fiber having a softening temperature of about 150° C. to 200° C. is used as the thermoplastic resin fiber, the heating temperature is preferably 170° C. to 250° C. More preferably, the heating temperature is 170°C to 210°C in order to suppress the decomposition of the regenerated cellulose fiber. When the pressure treatment is performed in addition to the heat treatment, the pressure is preferably 1 MPa to 10 MPa.

When the heat treatment and the pressure treatment are performed, a hot press machine may be used. Alternatively, the heat treatment may be performed first, and then the pressure treatment may be performed while the thermoplastic resin is in the molten or softened state.

In the case of producing a composite molded body having a higher basis weight, heat treatment and/or pressure treatment may be carried out by laminating a plurality of sheet base materials. In that case, the plurality of sheet base materials may be mechanically (for example, by stitching) or chemically (for example, by adhesion) previously integrated and then subjected to heat treatment and/or pressure treatment.

According to this embodiment, a sheet-shaped composite molded body can be obtained, or a three-dimensional structure can be obtained by imparting a three-dimensional shape during heat treatment and/or pressure treatment. A composite molded body can be obtained. The sheet-shaped composite molded body (stampable sheet) can be made into a shape having irregularities by further subjecting it to hot pressing. In that case, a plurality of sheet-shaped composite molded bodies may be laminated and subjected to hot pressing to obtain a thicker composite molded body.

It goes without saying that the manufacturing method of the present embodiment is one mode for manufacturing the composite molded body of the present invention, and the composite molded body of the present invention may be manufactured by another manufacturing method depending on its shape. For example, a sheet-shaped composite molded body may be manufactured by a method in which a thermoplastic resin melted by impregnation or coating is applied to a fiber sheet made of regenerated cellulose fibers.

(Use of composite molded body)
The composite molded article of the present invention is a material for space and aircraft, a material for ships, a material for vehicles (including automobiles and bicycles), a material for sports equipment, a material for OA equipment, a material for electronic equipment, an industrial material, tanks and containers. It can be used as a material, a miscellaneous goods material, and a construction material. Specifically, the composite molded body of the present invention is suitable for constituting automobile interior materials and sound absorbing materials, suitcase bodies, and casings of personal computers, mobile phones, copy machines, multifunction machines, game machines, and the like. ing.

The following were prepared as regenerated cellulose fibers.
Regenerated Cellulose Fiber A:
A viscose rayon having a fineness of 1.7 dtex and a fiber length of 51 mm, prepared was a flame-retardant regenerated cellulose fiber containing an aromatic phosphate ester as a flame retardant (trade name DFG, manufactured by Daiwa Bou Rayon Co., Ltd.), crimped. Number 11.8/25 mm, single fiber strength 2.18 cN/dtex, limiting oxygen index 29).

Regenerated cellulose fiber B:
A viscose rayon with a fineness of 1.7 dtex and a fiber length of 51 mm was prepared (trade name: Corona RB, manufactured by Daiwa Bourayon Co., Ltd.), crimp number: 12.4 pieces/25 mm, single fiber strength: 2.28 cN/dtex, limiting oxygen Index 18.4).

The following were prepared as the thermoplastic resin fibers.
Thermoplastic resin fiber A:
A polycarbonate fiber having a fineness of 6.7 dtex and a fiber length of 64 mm was prepared. This polycarbonate fiber was manufactured by the following method. Polycarbonate (M7020J, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was melt-spun at a spinning temperature of 300° C. to obtain a spun filament having a fineness of 6.7 dtex. A fiber treating agent was applied, and crimps of 15 pieces/25 mm were applied using a stuffing box type crimper, and after drying, the fibers were cut into fiber lengths of 64 mm. The polycarbonate fiber had a single fiber strength of 2.5 cN/dtex and a limiting oxygen index of 26.

Thermoplastic resin fiber B:
A polypropylene fiber having a fineness of 2.2 dtex and a fiber length of 51 mm and containing 3% by mass of an N-alkoxy hindered amine monomer as a flame retardant was prepared. This polypropylene fiber was manufactured by the following method. A flame retardant was added to polypropylene having a melting point of 165°C (trade name: SA03, manufactured by Nippon Polypro Co., Ltd.) and melt-spun at a spinning temperature of 230°C to obtain a spun filament having a fineness of 6.6 dtex. Then, the spun filament was drawn 3 times in hot air at 130°C to obtain a fineness of 2.2 dtex, and then a fiber treatment agent was added, and further, a crimp of 15 pieces/25 mm was applied by a stuffing box type crimper. Then, after drying, it was cut into a fiber length of 51 mm. The polypropylene fiber had a single fiber strength of 4.0 cN/dtex and a limiting oxygen index of 28.

In the above, the single fiber strength is a load value when the fiber is cut when a tensile test is performed using a tensile tester with a gripping interval of the sample being 20 mm in accordance with JIS L 1015.

(Example 1)
40% by mass of regenerated cellulose fiber A and 60% by mass of thermoplastic resin fiber A (polycarbonate fiber) were mixed to obtain a card web by a roller card machine. This web was subjected to a needle punching process using a 40 count needle under the conditions of a needle depth of 10 mm and a density of 130 needles/cm ² to obtain a needle punched nonwoven fabric of 1.0 mm in thickness. This non-woven fabric was subjected to heat and pressure treatment using a hot press machine under the conditions of a temperature of 200° C. and a pressure of 3 MPa to obtain a sheet-shaped composite molded body in which the thermoplastic resin fibers were completely melted.

(Example 2)
40% by mass of regenerated cellulose fiber A and 60% by mass of thermoplastic resin fiber B (polypropylene fiber) were mixed and a card web was obtained by a roller card machine. This web was subjected to a needle punching process using a 40 count needle under the conditions of a needle depth of 10 mm and a density of 130 needles/cm ² to obtain a needle punched nonwoven fabric having a thickness of 1.0 mm. This non-woven fabric was subjected to heat and pressure treatment using a hot press machine under the conditions of a temperature of 200° C. and a pressure of 3 MPa to obtain a sheet-shaped composite molded body in which the thermoplastic resin fibers were completely melted.

(Comparative example 1)
A regenerated cellulose fiber B 40% by mass and a thermoplastic resin fiber A 60% by mass are mixed to produce a fibrous web by the same procedure as in Example 1, and a thermoplastic resin fiber is completely melted from the fibrous web into a sheet form. Was produced.

(Comparative example 2)
40% by mass of regenerated cellulose fibers and 60% by mass of thermoplastic resin fibers B were mixed to prepare a fibrous web in the same procedure as in Example 1, and the thermoplastic resin fibers were completely melted from the fibrous web into a sheet form. Was produced.

Table 1 shows the areal weight, thickness, specific volume, tensile strength, elongation and breaking length, and flame retardancy of the composite molded articles of Examples and Comparative Examples. The basis weight, thickness, specific volume, tensile strength and breaking length, and flame retardancy were determined according to the following methods.

(Basis weight)
The sample was cut into a size of 15 cm×15 cm, and its weight was measured and determined.
(Thickness)
Using a non-woven fabric thickness meter (trade name "THICKNESS GAUGE", model: CR-60A, manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.), a load of 20 g per 1 cm ^{2 of} the sample is applied according to JIS L 1096 did.
(Specific volume)
It was calculated from the basis weight and the thickness.

(Tensile strength)
According to JIS L 1096, a sample piece having a width of 5 cm and a length of 15 cm is gripped so that a chuck interval is 10 cm, and a constant speed extension type tensile tester (trade name: Tensilon UCT-1T manufactured by Orientec Co., Ltd.) is used. The test piece was stretched at a tensile speed of 30 cm/min, and the load value at break and the elongation rate were measured as the breaking strength and the breaking elongation, respectively.
(Breaking length)
From the tensile strength and the basis weight, it was calculated by the following formula.
Breaking length (km) = [tensile strength (N / 5cm) /9.8) × 1000] / [ the width of the tensile strength measurement sample (mm) × basis weight (g / m ^2)]

(Flame retardance)
For Example 1 and Comparative Example 1, evaluation was performed according to UL94HB and V class test methods and criteria, and for Example 2 and Comparative Example 2, evaluation was performed according to JIS L 1091 A-1 method. did. However, in Comparative Example 1, the combustion was so remarkable that substantial evaluation could not be performed.

From the comparison between Example 1 and Comparative Example 1 and the comparison between Example 2 and Comparative Example 2, the use of viscose rayon containing a flame retardant as the reinforcing fiber results in a flame retardance of the obtained composite molded article. It turned out that it improves significantly. In addition, Example 1 has improved mechanical properties such as tensile strength and breaking length as compared with Comparative Example 1, and the flame retardant added to viscose rayon disperses the fibers in the matrix and/or Alternatively, the affinity between polycarbonate and viscose rayon may be improved.

The present invention includes the following aspects.
(Aspect 1)
A flame-retardant composite molding substrate comprising a regenerated cellulose fiber and a thermoplastic resin, wherein the regenerated cellulose fiber has a limiting oxygen index of 26 or more.
(Aspect 2)
The flame-retardant composite molding substrate according to aspect 1, wherein the thermoplastic resin forms a carbonized layer by combustion, and the carbonized layer exhibits self-extinguishing property by preventing further combustion.
(Aspect 3)
The flame-retardant composite molding substrate according to aspect 1 or 2, wherein the substrate is a non-woven fabric, and the thermoplastic resin is contained as a thermoplastic resin fiber.
(Aspect 4)
The flame-retardant composite molding substrate according to aspect 3, wherein the thermoplastic resin fibers are one or more fibers selected from polycarbonate fibers, polyetherimide fibers, and polyphenylene ether fibers.
(Aspect 5)
A flame-retardant composite molded article comprising regenerated cellulose fibers as reinforcing fibers and a thermoplastic resin as a matrix, wherein the regenerated cellulose fibers have a limiting oxygen index of 26 or more.
(Aspect 6)
The flame-retardant composite molded article according to aspect 5, wherein the thermoplastic resin forms a carbonized layer by combustion and the carbonized layer exhibits self-extinguishing property by preventing further combustion.
(Aspect 7)
The flame-retardant composite molded article according to aspect 5 or 6, wherein the thermoplastic resin is one or more resins selected from polycarbonate, polyetherimide, and polyphenylene ether.
(Aspect 8)
Producing a composite molding substrate containing a regenerated cellulose fiber having a limiting oxygen index of 26 or more and a thermoplastic resin, and heating the composite molding substrate at a temperature at which the thermoplastic resin melts or softens. A method for producing a flame-retardant composite molded article, including:
(Aspect 9)
The flame retardant according to aspect 8, wherein the composite molding substrate is a fiber sheet containing the thermoplastic resin as a thermoplastic resin fiber, and further comprising pressurizing the fiber sheet to obtain a sheet-shaped flame-retardant composite molded article. Of a flexible composite molded article.
(Aspect 10)
The method for producing a flame-retardant composite molded article according to aspect 9, wherein the thermoplastic resin fiber forms a carbonized layer by combustion, and the carbonized layer exhibits self-extinguishing property by preventing further combustion.
(Aspect 11)
The method for producing a flame-retardant composite molded article according to aspect 9 or 10, wherein the thermoplastic resin fibers are one or more fibers selected from polycarbonate fibers, polyetherimide fibers, and polyphenylene ether fibers.

The composite molded article of the present invention is a material for space and aircraft, a material for ships, a material for vehicles (including automobiles and bicycles), a material for sports equipment, a material for OA equipment, a material for electronic equipment, an industrial material, tanks and containers. It is useful as a material, a miscellaneous goods material, and a construction material.

Claims (11)

Play containing cellulosic fibers and thermoplastic resin, a composite molding substrate, the regenerated cellulose fibers, have a more than 26 limiting oxygen index, the thermoplastic resin is a carbonized layer is formed by burning, the A flame-retardant composite molding substrate (excluding those containing metal-plated synthetic fibers) characterized in that the carbonized layer exhibits self-extinguishing property by preventing further combustion . The flame-retardant composite molding substrate according to claim 1, wherein the substrate is a non-woven fabric, and the thermoplastic resin is contained as a thermoplastic resin fiber. Basis weight is ^{400g / m 2 ~12000g / m 2} , the flame retardant composite molding substrate according to claim 2. The thermoplastic resin fibers, polycarbonate fibers, polyetherimide fibers, and is selected from polyphenylene ether fibers, 1 or more fibers, flame-retardant composite molding substrate according to claim 2 or 3. A non-woven fabric composite molding substrate containing regenerated cellulose fibers and a thermoplastic resin, wherein the regenerated cellulose fibers have a limiting oxygen index of 26 or more and a basis weight of 400 g/m 2. ^Two ~ 12000g/m ^Two The flame-retardant composite molding base material (excluding those containing metal-plated synthetic fibers). A composite molding base material, which is a non-woven fabric, containing regenerated cellulose fibers and thermoplastic resin fibers, wherein the regenerated cellulose fibers have a limiting oxygen index of 26 or more, and the thermoplastic resin fibers are polycarbonate fibers or polyether. A flame-retardant composite molding base material (excluding those containing metal-plated synthetic fibers), which is selected from imide fibers and polyphenylene ether fibers. Regenerated cellulose fibers are contained as the reinforcing fiber carbide, a composite molding the thermoplastic resin is contained as a matrix, wherein the regenerated cellulose fibers, have a more than 26 limiting oxygen index, the thermoplastic resin, the combustion A flame-retardant composite molded article (excluding those containing metal-plated synthetic fibers), which is characterized in that it forms a layer and the carbonized layer exhibits self-extinguishing property by preventing further combustion . A composite molded article containing regenerated cellulose fibers as reinforcing fibers and a thermoplastic resin as a matrix, wherein the regenerated cellulose fibers have a limiting oxygen index of 26 or more, and the thermoplastic resin has a fiber shape. Flame-retardant composite moldings (excluding those containing metal-plated synthetic fibers) that are not characterized . A base material for composite molding (however, a regenerated cellulose fiber having a limiting oxygen index of 26 or more and a thermoplastic resin which forms a carbonized layer by burning and exhibits self-extinguishing property by preventing the carbonized layer from further burning (however, a metal is used). Of a flame-retardant composite molded article, which comprises heating the composite molding base material at a temperature at which the thermoplastic resin melts or softens. Production method. The base material for composite molding is a fiber sheet containing the thermoplastic resin as a thermoplastic resin fiber, and further comprising pressurizing the fiber sheet to obtain a sheet-shaped flame-retardant composite molded article. A method for producing a flame-retardant composite molded article. The flame-retardant composite molding according to claim 10, wherein heating the thermoplastic resin fibers at a temperature for melting or softening includes completely melting the thermoplastic resin fibers to lose the fiber shape. Body manufacturing method.