JP6878058B2 - Non-woven fabric for molding and exterior materials for automobiles - Google Patents

Description

The present invention relates to non-woven fabrics for molding and exterior materials for automobiles. The non-woven fabric for molding of the present invention can be molded and suitably used as an exterior material for automobiles such as a fender liner, an engine undercover, and a body undercover.

Conventionally, as a sound absorbing material for automobiles, a laminated body in which fiber sheets are laminated has been proposed. For example, "a non-woven fabric having a texture of 10 to 300 g / m ² , a breathability of 1.5 to 10 cc / cm ² / sec, and an average fineness of constituent fibers of 0.1 to 2 dtex, and a non-woven fabric having a density of 0.01 to 0.01 to A sound absorbing structure formed by laminating a fiber structure having a thickness of 0.10 g / cm ³ and a thickness of 5 to 100 mm and an average fineness of constituent fibers of 0.5 to 10 dtex, and the layer made of the non-woven fabric is on the sound source side. A sound-absorbing structure characterized by being arranged in a non-woven fabric. ”(Patent Document 1) has been proposed. Although such a sound absorbing structure is excellent in sound absorbing property, it has low rigidity, so that it is difficult to actually apply it to an automobile application, particularly an automobile exterior material application.

Such a problem of rigidity has been a problem not only when applied to automobile applications but also when used for other applications such as partition applications and wallpaper applications.

Japanese Unexamined Patent Publication No. 2004-145180

When the present inventor examined the low rigidity of the sound absorbing structure, the sound absorbing structure was imparted with sound absorbing property by ^{setting the air permeability to 1.5 to 10 cc / cm 2 / sec.} , It was found that this is because it is prepared by impregnating with a resin to obtain the above-mentioned air permeability. That is, when the resin was impregnated, the resin was localized around the intersection of the fibers, and there was no connection with the intersection of the adjacent fibers, so that the rigidity was found to be low.

The present invention has been made based on such findings, and an object of the present invention is to provide a non-woven fabric for molding capable of achieving both sound absorption and rigidity, and an exterior material for automobiles.

The non-woven fabric for molding of the present invention is a non-woven fabric for molding having a surface non-woven fabric layer on one side or both sides of a bulky non-woven fabric layer having a thickness of 3 to 10 mm. The fixed tensile elastic gradient is 150 N / mm or more, and the air permeability is 0.1 to 4.0 ^{cm 3} / cm ² / sec. Consists of a non-woven fabric layer.

It is preferable that the bending elastic modulus of the non-woven fabric for molding is 350 MPa or more and the fineness of the fibers constituting the surface non-woven fabric layer is 2.2 to 6.6 dtex. Further, the non-woven fabric for molding of the present invention preferably comprises only organic components.

The exterior material for automobiles of the present invention is a molded non-woven fabric for molding.

The non-woven fabric for molding of the present invention has a bulky non-woven fabric layer and a surface non-woven fabric layer bonded by polypropylene having porous properties, and has a surface non-woven fabric layer, and the surface non-woven fabric layer has fibers formed by a continuously extending polypropylene-based resin. It is fixed and has excellent rigidity with a tensile elastic gradient of 150 N / mm or more. In addition, the air permeability of the surface non-woven fabric is 0.1 to 4.0 ^{cm 3} / cm ² / sec. Therefore, in addition to the fact that air easily vibrates and is easily absorbed as heat energy by friction, it is excellent in sound absorption because it is provided with a bulky non-woven fabric layer having a thickness of 3 to 10 mm.

The non-woven fabric for molding of the present invention preferably has an excellent rigidity with a flexural modulus of 350 MPa or more.

Further, when the fineness of the fibers constituting the surface non-woven fabric layer is 2.2 to 6.6 dtex, the non-woven fabric for molding having more excellent rigidity can be obtained.

Further, when the non-woven fabric for molding is composed of only organic components, it is a non-woven fabric for molding which is excellent in workability and easy to dispose of after use. That is, it is conceivable to use inorganic fibers such as glass fibers in order to impart rigidity, but inorganic fibers such as glass fibers have poor workability such as being stuck in a finger during molding work, and after use. While it was necessary to dispose of it as industrial waste and it was difficult to dispose of it, the non-woven fabric for molding, which consists only of organic components, has excellent workability because it does not stick during molding work, and after use. Can be incinerated and is easy to dispose of.

Since the exterior material for automobiles of the present invention is obtained by molding the non-woven fabric for molding, it is excellent in rigidity and sound absorption.

Electron micrograph of the surface of the surface non-woven fabric of the present invention Electron micrograph of the surface of the non-woven fabric bonded with a liquid binder

The non-woven fabric for molding of the present invention has tensile elasticity in which fibers are fixed by a polypropylene-based resin (hereinafter, may be referred to as "PP resin") that extends continuously as a surface non-woven fabric layer so that the non-woven fabric for molding has excellent rigidity. A non-woven fabric layer having a gradient of 150 N / mm or more is provided. In addition, the air permeability of the surface non-woven fabric layer is 0.1 to 4.0 ^{cm 3} / cm ² / sec. Moreover, it is provided with a bulky non-woven fabric layer having a thickness of 3 to 10 mm.

The "nonwoven fabric layer" means a layer of a non-woven fabric having morphological stability that can be handled by the layer itself. That is, it means that the layer itself is in the state of a non-woven fabric in which fibers are bonded to each other by entanglement, adhesion, and / or fusion. Therefore, when the fibers are laminated in a fiber web state in which the fibers are not yet bonded to each other and then the fibers are bonded to each other to produce a non-woven fabric, the non-woven fabric layer is one layer and does not have two or more non-woven fabric layers. ..

The surface non-woven fabric layer of the present invention has a structure in which fibers are fixed by a continuously extending PP resin so as to have excellent rigidity. That is, when the fibers are fixed with the liquid binder as in the conventional case, the resin is localized around the intersection of the fibers as shown in FIG. 2 as an electromicrograph of the surface of the non-woven fabric bonded with the liquid binder. The surface non-woven fabric layer of the present invention is connected to the adjacent fibers by continuously extending the PP resin, and has high rigidity, whereas the surface non-woven fabric layer of the present invention is not connected to the intersection of the adjacent fibers and has low rigidity. It is a non-woven fabric layer. Such a state in which the PP resin is continuously stretched can be confirmed by taking an electron micrograph as shown in FIG. 1 as an example.

The surface non-woven fabric layer in which the PP resin in FIG. 1 is continuously and randomly stretched is formed, for example, after forming a fiber web containing polypropylene fibers containing polypropylene resin and then melting the polypropylene resin. It can be manufactured by solidifying. Further, the PP resin does not have to be continuously random, and may be regularly and continuously extended in one or two directions. In the surface non-woven fabric layer in which such PP resin is regularly and continuously extended in one or two directions, for example, filaments, yarns, etc. containing polypropylene resin are aligned and placed on the fiber web, and then the surface non-woven fabric layer is placed. Alternatively, it can be produced by placing a filament containing a polypropylene resin, a net made of yarn or the like, a woven fabric, or the like on a fiber web, melting the polypropylene resin, and then solidifying the resin.

Since this polypropylene-based resin has a low specific gravity, when the mass of the resin involved in fixing in the surface non-woven fabric layer is the same, the volume occupied by the PP resin is large, so that the rigidity of the surface non-woven fabric layer is high. Further, when the volume of the resin involved in fixing in the surface non-woven fabric layer is the same, the mass occupied by the PP resin is small, so that the surface non-woven fabric layer is lightweight or thin even though the rigidity is about the same. ..

This polypropylene-based resin can be a homopolymer of propylene, or can be a copolymer of propylene and an α-olefin (for example, ethylene, butene-1, etc.). More specifically, for example, an isotactic propylene homopolymer having crystallinity, an ethylene-propylene random copolymer having a low content of ethylene units, and a homo portion composed of a propylene homopolymer and a content of ethylene units. A propylene block copolymer composed of a copolymer composed of a relatively large amount of ethylene-propylene random copolymer, and further, each homo portion or copolymer portion in the propylene block copolymer further comprises, such as butene-1. Examples thereof include a crystalline propylene-ethylene-α-olefin copolymer obtained by copolymerizing α-olefin.

The content of the PP resin in such a surface non-woven fabric layer is such that the air permeability of the surface non-woven fabric layer is 0.1 to 4.0 ^{cm 3} / cm ² / sec. The fineness is not particularly limited because it varies depending on the fineness of the constituent fibers, but is, for example, a small fineness such that the fineness of the constituent fibers is 0.5 dtex or more and less than 2.2 dtex. In the case, it is preferably 20 to 60 mass%, and more preferably 25 to 55 mass%. When the fineness of the constituent fibers is as large as 2.2 dtex or more and 6.6 dtex or less, it is preferably 10 to 75 mass%, more preferably 20 to 60 mass%, and 25. Even more preferably, it is ~ 50 mass%.

In the surface non-woven fabric layer of the present invention, the fibers are fixed with the PP resin as described above, but the fibers have a melting point or a decomposition point higher than the melting point of the PP resin (preferably higher than 10 ° C., more preferably. Any fiber made of a resin (higher than 20 ° C., more preferably 30 ° C. or higher) may be used. Since the melting point of PP resin is usually 160 ° C., it is a fiber made of a resin having a melting point or a decomposition point higher than 160 ° C. (preferably 170 ° C. or higher, more preferably 180 ° C. or higher, still more preferably 190 ° C. or higher). All you need is.

More specifically, the surface non-woven layer constituent fibers include, for example, polyester fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, acrylic fibers, polyurethane fibers, nylon fibers, vinylon fibers, polylactic acid fibers and the like. Synthetic fibers; Regenerated fibers such as rayon fiber, polynosic fiber, cupra fiber, lyocell fiber; semi-synthetic fiber such as acetate fiber and triacetate fiber; plant fiber such as cotton and hemp; animal fiber such as wool and silk; be able to. Among these, polyester fibers are suitable because they are excellent in heat resistance, weather resistance, antifouling property and the like.

Further, the surface non-woven fabric layer constituent fibers may be composed of a single resin component, or may be composed of two or more kinds of resin components. When the surface non-woven fabric layer constituent fibers are composed of two types of resin components, for example, the arrangement in the cross section of the fibers can be side-by-side type, core-sheath type, eccentric type, multi-layer laminated type, or orange type.

The fineness of the fibers constituting the surface non-woven fabric layer is not particularly limited, but the air permeability of the surface non-woven fabric layer is 0.1 to 4.0 ^{cm 3} / cm ² / sec. It is preferably 6.6 dtex or less, more preferably 4.4 dtex or less, and further preferably 3.3 dtex or less so that On the other hand, the fineness of the surface nonwoven fabric layer constituent fibers is preferably 0.5 dtex or more, preferably 0.8 dtex or more, so that the rigidity of the surface nonwoven fabric layer is excellent and, as a result, the rigidity of the molding nonwoven fabric is excellent. Is more preferable, 1.1 dtex or more is further preferable, and 2.2 dtex or more is further preferable. When two types of fibers having different fineness are included as the surface non-woven fabric layer constituent fibers, it is preferable that the average fineness calculated by the following formula is within the fineness range. Further, when three or more kinds of fibers having different fineness are contained, the value calculated in the same manner is preferably within the fineness range.
Fav = 1 / [(Pa / 100) / Fa + (Pb / 100) / Fb]
Here, Fav is the average fineness (unit: dtex), Pa is the mass ratio of one fiber A (unit: mass%), Fa is the fineness of the fiber A (unit: dtex), and Pb is the mass ratio of the other fiber B. (Unit: mass%) and Fb mean the fineness (unit: dtex) of the fiber B, respectively. The "fineness" in the present invention means a value obtained by the method A specified in JIS L 1015: 2010, 8.5.1 (positive amount fineness).

The fiber length of the surface non-woven fabric layer constituent fibers is not particularly limited, but is preferably 30 to 80 mm, more preferably 40 to 70 mm so that the surface non-woven fabric layer has a uniform texture. It is more preferably 50 to 60 mm. The "fiber length" in the present invention means a value obtained by JIS L 1015: 2010, 8.4.1 [corrected staple diagram method (B method)].

The surface non-woven fabric layer constituent fibers can be colored fibers. The fibers colored in this way can enhance the design of the non-woven fabric for molding. The colored fibers can be obtained, for example, by kneading a pigment into the fibers or by dyeing the fibers with a dye.

In addition, the surface non-woven fabric layer can contain two or more types of fibers that differ in the type, number, and / or arrangement in cross section of the resin component; fineness, fiber length, presence or absence of coloring, and the like.

The fibers are preferably entangled with each other so that the surface non-woven fabric layer of the present invention has excellent rigidity. Such entanglement can be imparted, for example, by allowing a needle or water stream to act on the fiber web.

As described above, the surface non-woven fabric layer of the present invention is a non-woven fabric layer in which fibers are fixed by a polypropylene-based resin that extends continuously, and has a tensile elastic gradient of 150 N / mm or more so that rigidity can be imparted to the non-woven fabric for molding. .. The larger the tensile elastic gradient, the more rigid the non-woven fabric for molding can be imparted. Therefore, it is preferably 160 N / mm or more, and more preferably 165 N / mm or more. The upper limit of the tensile elastic gradient is not particularly limited, but is preferably 300 N / mm or less so that stress does not remain after molding and the shape does not change. The "tensile elastic gradient" means the tensile elastic gradient after the surface nonwoven fabric layer is peeled off from the non-woven fabric for molding, and is a value obtained by the following procedure.

(1) From the surface non-woven fabric layer, three test pieces of 200 mm in the longitudinal direction and 50 mm in the direction orthogonal to the longitudinal direction are collected.
(2) The thickness (d, unit: mm) of the test piece is ^{measured under the conditions of a contact area of 5 cm 2} and a pressing force of 2.0 kPa.
(3) Using a tensile tester [manufactured by Instron], the distance between chucks is 100 mm and the tensile speed is 200 mm / min. Perform a tensile test under the conditions of, and measure the tensile elastic modulus (Em, unit: N / m ² ).
(4) The tensile elastic gradient (TEG, unit: N / mm) is calculated from the following equations.
TEG = Em × d
(5) The arithmetic mean value of the tensile elastic gradients of the three test pieces is calculated and used as the tensile elastic gradient of the present invention.

Further, the surface non-woven fabric layer of the present invention has a breathability of 0.1 to 4.0 ^{cm 3} / cm ² / sec. However, in order to have better sound absorption, 0.2 to 3.8 ^{cm 3} / cm ² / sec. It is preferably 0.3 to 3.6 ^{cm 3} / cm ² / sec. Is more preferable. For this "breathability", the air permeability of three test pieces collected from the surface non-woven fabric layer was measured by 6.8.1 (Frazier method) specified in JIS L1913: 2010 "General non-woven fabric test method". , The arithmetic mean value of the air permeability of each test piece is taken as the air permeability of the present invention. The test piece is prepared by peeling the surface non-woven fabric layer from the non-woven fabric for molding.

The basis weight and thickness of the surface non-woven fabric layer of the present invention may be as long as they have the above-mentioned air permeability, and are not particularly limited, but the basis weight is preferably 100 to 400 g / m 2, and 150 to 150 to ^{m 2.} It is more preferably 350 g / m ² , and even more preferably 200 to 300 g / m ² . The thickness is preferably 0.25 to 0.50 mm, more preferably 0.25 to 0.45 mm, and even more preferably 0.30 to 0.40 mm. In the present invention, "Metsuke" refers to ^{the mass per 1 m 2 on the} surface having the largest area, and "thickness" refers to the thickness under a load ^{of 20 g / cm 2.}

The surface-woven fabric constituting such a surface-woven fabric layer of the present invention can be produced, for example, by the following method. First, the surface non-woven fabric layer constituent fibers (preferably polyester fibers) as described above are prepared. Further, a polypropylene fiber containing a polypropylene resin as a base of the PP resin (hereinafter, may be simply referred to as “PP fiber”) is prepared.

The PP fiber may be composed of only the PP resin, or may be composed of a resin other than the PP resin. For example, when the PP fiber is composed of two kinds of resin components, for example, the arrangement in the cross section of the fiber can be side-by-side type, core-sheath type, eccentric type, multi-layer laminated type, or orange type. Among these, when the PP fiber is composed of only PP resin, it is preferable because the amount of PP resin that can be involved in fixing the surface non-woven fabric layer constituent fiber is large.

The fineness of the PP fiber is not particularly limited, but the air permeability of the surface non-woven fabric layer is 0.1 to 4.0 ^{cm 3} / cm ² / sec. It is preferably 1.1 to 11.0 dtex, more preferably 2.2 to 8.8 dtex, and 3.3 to 3.3 to be easy to obtain and the rigidity of the surface non-woven fabric layer is excellent. It is more preferably 6.6 dtex. When the PP fiber contains two or more types of fibers having different fineness, it is preferable that the average fineness calculated by the same formula as described above is within the fineness range.

The fiber length of the PP fiber is not particularly limited, but is 30 to 80 mm so that the surface nonwoven fabric constituent fibers can be fixed in a continuously stretched state and the surface nonwoven fabric has a uniform texture. It is preferably 40 to 70 mm, more preferably 50 to 60 mm, and even more preferably 50 to 60 mm.

The PP fiber can also be a colored fiber. The PP fibers colored in this way do not impair the design of the non-woven fabric for molding due to the surface non-woven fabric layer constituent fibers. The colored PP fiber can be obtained, for example, by kneading a pigment into the PP fiber or by dyeing the PP fiber with a dye. In addition, the surface non-woven fabric layer can contain two or more types of PP fibers that differ in the type, number, and / or arrangement in the cross section of the PP resin; fineness, fiber length, presence or absence of coloring, and the like.

Next, a fiber web containing the surface non-woven fabric layer constituent fibers and PP fibers as described above is formed. The fiber web may be formed by any method, and can be formed by, for example, a dry method such as a card method or an air array method, or a wet method. Among these, it is preferable to have a certain thickness so as to have excellent rigidity, so it is preferable to form a fiber web by a dry method.

The orientation direction of the fiber web constituent fibers is not particularly limited, but intersects the longitudinal direction of the fiber web so that the fixing with the PP resin derived from the PP fiber is continuous and uniform. It is preferable to do so. The fiber web in which the constituent fibers intersect in this way can be obtained, for example, by orienting the card web oriented in one direction in the lateral direction with a cross layer or the like.

Next, the surface non-woven fabric of the present invention can be obtained by melting and then solidifying the PP resin of the PP fibers constituting the fiber web, but by using a needle or a water stream so that the rigidity can be further increased. , It is preferable to entangle the fibers with each other. In particular, it is preferable that the polypropylene resin is strongly entangled with a needle so that it does not move easily when it melts, stays at the position before the polypropylene resin melts, and can fix the fiber in a continuously stretched state. The entanglement condition may be appropriately set in consideration of the rigidity of the surface non-woven fabric and the like, and is not particularly limited. However, when entwined with a suitable needle, the needle density is 100 to 300 needles / cm ^2. It is preferable to entangle at 150 to 250 lines / cm ² , and it is more preferable to entangle at 150 to 250 lines / cm 2.

Then, the surface non-woven fabric of the present invention can be produced by melting and then solidifying the PP fibers constituting the fiber web (preferably the entangled fiber web). The melting and solidification of the PP fiber can be carried out by simultaneously heating and pressurizing, or by pressurizing after heating. For example, heating and pressurization can be performed simultaneously by using a heating roll, a flat plate press, etc., and after heating in an oven or the like, pressurization is performed by a pair of rolls, a flat plate press, or the like having a temperature lower than the heating temperature. For example, heating and pressurization can be performed separately. The heating conditions were such that the fibers were fixed by a continuously extending PP resin, and the air permeability was 0.1 to 4.0 ^{cm 3} / cm ² / sec. The condition is not particularly limited as long as it can be used as the surface non-woven fabric layer of the above, but the surface non-woven fabric is above the melting point of the PP resin (160 ° C. or higher, preferably 170 ° C. or higher, more preferably 180 ° C. or higher). It is preferable to heat the layered fiber to a temperature lower than the melting point. Since the pressurizing conditions differ depending on the heating conditions and the like, the air permeability is appropriately set.

The above is a method for producing a surface non-woven fabric by including PP fibers in a fiber web. On a fiber web containing or not containing PP fibers, filaments, yarns, etc. containing polypropylene resin are aligned and placed. After that, or after placing a net, a woven fabric, etc. made of filaments, yarns, etc. containing polypropylene resin, the polypropylene-based resin constituting the filaments, yarns, nets, woven fabrics, etc. was melted in the same manner as described above. The surface non-woven fabric of the present invention can also be produced by solidifying it later.

The non-woven fabric for molding of the present invention has, in addition to the above-mentioned surface non-woven fabric layer, a bulky non-woven fabric layer having a thickness of 3 to 10 mm so as to have excellent sound absorption and rigidity. The preferred bulky non-woven fabric layer has a thickness of 4 to 8 mm, and the more preferred bulky non-woven fabric layer has a thickness of 4 to 6 mm. This "thickness" is the arithmetic mean value of the thickness of the bulky non-woven fabric layer at 5 randomly selected points by taking a stereomicrograph of the non-woven fabric for molding in the thickness direction cross section under a load of 2.0 kPa. means.

The fibers constituting the bulky non-woven layer of the present invention are not particularly limited, but are, for example, polyester fibers, polyolefin fibers (for example, polypropylene fibers, polyethylene fibers, etc.), polyvinylidene chloride fibers, and polyvinyl chloride. Synthetic fibers such as synthetic fibers, acrylic fibers, polyurethane fibers, nylon fibers, vinylon fibers, polylactic acid fibers; recycled fibers such as rayon fibers, polynosic fibers, cupra fibers, lyocell fibers; half of acetate fibers, triacetate fibers, etc. Synthetic fibers; plant fibers such as cotton and hemp; animal fibers such as wool and silk; and the like. Among these, polyester fibers are suitable because they are excellent in heat resistance, weather resistance, antifouling property and the like.

The bulky nonwoven fabric layer constituent fiber may be composed of a single resin component, or may be composed of two or more kinds of resin components. When the bulky nonwoven fabric layer constituent fibers are composed of two types of resin components, for example, the arrangement in the cross section of the fibers can be side-by-side type, core-sheath type, eccentric type, multi-layer laminated type, or orange type.

The fineness of the bulky nonwoven fabric layer constituent fibers is not particularly limited, but there are many bonding points between the bulky nonwoven fabric layer constituent fibers and the bonding points between the bulky nonwoven fabric layer and the surface nonwoven fabric layer, and the bulky nonwoven fabric layer can also be used for molding. It is preferably 1.1 to 11 dtex, more preferably 2.2 to 8.8 dtex, and even more preferably 3.3 to 7.7 dtex so that rigidity can be imparted to the non-woven fabric. When two or more types of fibers having different fineness are contained as the bulky non-woven fabric layer constituent fiber, it is preferable that the average fineness calculated by the above formula is within the fineness range.

The fiber length of the bulky nonwoven fabric layer constituent fibers is not particularly limited, but is preferably 30 to 80 mm, more preferably 40 to 70 mm so that the bulky nonwoven fabric layer has a uniform texture. It is more preferably 50 to 60 mm.

The bulky non-woven fabric layer constituent fiber can be a colored fiber, and in particular, when it is colored in the same color as the surface nonwoven fabric layer constituent fiber, it prevents see-through during molding and does not easily impair the appearance. It is preferable that the fibers are colored in the same hue as the fibers constituting the non-woven fabric layer. The colored fibers can be obtained, for example, by kneading a pigment into the fibers or by dyeing the fibers with a dye.

In addition, the bulky nonwoven layer can contain two or more types of fibers that differ in the type, number, and / or arrangement in cross section of the resin component; fineness, fiber length, presence or absence of coloring, and the like.

It is preferable that the fibers are fused to each other so that the bulky nonwoven fabric layer of the present invention has excellent rigidity. The bulky nonwoven fabric in which the fibers are fused to each other can be obtained, for example, by forming a fiber web containing the heat-sealing fibers and then fusing the heat-sealing fibers. The heat-bondable fiber may be composed of a single resin component or two or more types of resin components, but the fiber morphology is maintained even after fusion and the bulky non-woven fabric layer is formed. It is preferably composed of two or more kinds of resin components so as to have excellent rigidity. For example, a low melting point fiber having a high melting point resin component and a low melting point resin component and having a side-by-side type, a core-sheath type, an eccentric type, a multi-layer laminated type, or an orange type arranged in the cross section of the fiber. Since only the melting point resin component is fused, a bulky non-woven fabric layer having excellent rigidity can be obtained.

Further, it is preferable that the fibers are entangled with each other so that the bulky nonwoven fabric layer of the present invention has excellent rigidity. Such entanglement can be imparted, for example, by allowing a needle or water stream to act on the fiber web. It is preferable that the non-woven fabric layer is entangled by the action of a needle so that the non-woven fabric layer can be bulky. As described above, since the fibers of the bulky non-woven fabric layer constituent fibers are preferably fused to each other, they are preferably entangled and fused together. In producing such a bulky non-woven fabric, the fibrous non-woven fabric is fused so as not to break the fusion between the fibers and in a state where there are many intersections between the fibers, so that the bulky non-woven fabric has more excellent rigidity. In addition, it is preferable that the fiber web containing the heat-sealing fibers is entangled with a needle or a water stream, and then the heat-sealing fibers are fused.

Basis weight of such a bulky nonwoven fabric layer may be any thickness as described above is not particularly limited, is preferably from 500 to 2000 g / ^{m 2,} in the range of 700~1800g / ^{m 2} Is more preferable, and 900 to 1500 g / m ² is even more preferable.

The bulky nonwoven fabric constituting such a bulky nonwoven fabric layer of the present invention can be produced, for example, by the following method. First, the bulky non-woven fabric layer constituent fibers (preferably polyester fibers, heat-sealing fibers) as described above are prepared.

Next, a fiber web is formed by using the bulky non-woven fabric layer constituent fibers (preferably polyester fibers and heat-sealing fibers) as described above. The fiber web may be formed by any method, but it is preferably formed by a dry method such as a card method or an air array method, which easily forms a bulky fiber web.

The orientation direction of the fiber web constituent fibers is not particularly limited, and may be unidirectional, regularly intersected, or random.

Next, it is preferable to entangle the fibers with a needle or a water stream so that the rigidity of the bulky nonwoven fabric can be increased. In particular, since the bulky non-woven fabric is bulky, it is preferable to entangle it with a needle. The entanglement conditions may be appropriately set in consideration of the thickness, rigidity, etc. of the bulky non-woven fabric, and are not particularly limited. However, when entwined with a suitable needle, the needle density is 50 to 400. / cm ² is preferred to entanglement with, it is more preferable to entangled at 100 to 300 present / cm ^2.

Then, it is preferable to produce a bulky nonwoven fabric by fusing the heat-sealing fibers constituting the fiber web (preferably the entangled fiber web). The fusion with the heat-sealing fibers can be carried out, for example, by heating and pressurizing, or by heating only under no pressure. In particular, when heating and pressurization are performed, a bulky non-woven fabric having excellent rigidity can be produced, which is a preferable production method. Heating and pressurization can be performed simultaneously using a heating roll, a flat plate press, etc., and after heating in an oven or the like, a pair of rolls having a temperature lower than the heating temperature, a flat plate press, etc. Pressurization can be performed and heating and pressurization can be performed separately. The heating conditions are not particularly limited as long as they are at a temperature at which the heat-sealing fibers are fused, but are not particularly limited, but are higher than the melting point of the low melting point resin component of the heat-sealing fibers (preferably at a temperature higher than 10 ° C.). It is preferable to heat at a temperature higher than 20 ° C., more preferably 30 ° C. or higher) to a temperature lower than the melting point of the bulky non-constituent fiber. Since the pressurizing conditions differ depending on the heating conditions and the like, set them appropriately.

The above is a method for producing a bulky non-woven fabric in which heat-sealing fibers are fused after being entangled by a needle punch or the like, but only entanglement is performed by a needle punch or the like without fusing the heat-sealing fibers. The non-woven fabric can be a bulky non-woven fabric, and the non-woven fabric can be a non-woven fabric in which only heat-sealing fibers are fused without being entangled by a needle punch or the like.

Since the non-woven fabric for molding of the present invention has the above-mentioned surface non-woven fabric layer on one side or both sides of the bulky non-woven fabric layer, the rigidity is excellent in addition to the rigidity of the surface non-woven fabric layer and the combination with the bulky non-woven fabric layer. More specifically, the non-woven fabric for molding preferably has a flexural modulus of 350 MPa or more, more preferably 360 MPa or more, further preferably 370 MPa or more, and further preferably 380 MPa or more. The flexural modulus of the non-woven fabric for molding is not particularly limited, but is preferably 500 MPa or less so that stress does not remain after molding and the shape does not change.

The "flexural modulus" of the present invention is determined by the method A specified in JIS K 7171: 2016, 9.3 (flexural modulus) for three test pieces collected from a molding non-woven fabric under the following conditions. It is the value obtained by measuring the flexural modulus and arithmetically averaging the flexural modulus of each test piece.

(1) Test piece: A rectangular test piece having a width of 50 mm in the direction orthogonal to the longitudinal direction and a length of 150 mm in the longitudinal direction (2) Pressurizing speed: 20 mm / min.
(3) Distance between fulcrums: 100 mm
(4) Indenter radius: 2.25 mm
(5) Radius of support base: 2.00 mm

The non-woven fabric for molding of the present invention has excellent sound absorption, and specifically, the sound absorption coefficient at a frequency of 1000 Hz and the sound absorption coefficient at a frequency of 2000 Hz are 0.16 or more (preferably 0.17 or more) and 0. It is excellent in sound absorption of 40 or more (preferably 0.42 or more). The reason why the sound absorption coefficient at frequencies of 1000 Hz and 2000 Hz is illustrated is that the sound absorption coefficient at frequencies around 800 to 2000 Hz is emphasized in order to suppress the noise emitted to the outside of the vehicle when the vehicle is running. The sound absorption coefficient is measured by using a vertical incident method sound absorption coefficient measuring device manufactured by Bruel Care Co., Ltd. for three test pieces collected from the non-woven fabric for molding, and measuring the sound absorption coefficient by a measurement method based on JIS-A1405. Then, the calculated average value of the sound absorption coefficient of these test pieces is taken as the sound absorption coefficient of the present invention.

The non-woven fabric for molding of the present invention has a surface non-woven fabric on one side or both sides of the bulky non-woven fabric, but when the surface non-woven fabric is provided on both sides, the surface non-woven fabric may be the same, and the type and number of resin components of the constituent fibers. , And / or arrangement in cross section; fineness of constituent fibers, fiber length, presence / absence of coloring; presence / absence of entanglement of constituent fibers; tensile elastic gradient of surface non-woven fabric; air permeability of surface non-woven fabric; texture of surface non-woven fabric; thickness of surface non-woven fabric It may be different in at least one point such as. When the surface non-woven fabric layers are different, the air permeability of at least one of the surface non-woven fabric layers is 0.1 to 4.0 ^{cm 3} / cm ² / sec. Moreover, the tensile elastic gradient may be 150 N / mm or more.

The non-woven fabric for molding of the present invention includes the bulky non-woven fabric layer and the surface non-woven fabric layer as described above, but the non-woven fabric for molding is preferably composed of only organic components. This is because if the non-woven fabric for molding is composed of only organic components, it is excellent in workability and easy to dispose of after use. In other words, if inorganic fibers such as glass fibers are used to impart rigidity, workability is poor, such as the inorganic fibers such as glass fibers sticking to fingers during molding work, and they are treated as industrial waste after use. In contrast to the fact that it is difficult to dispose of the non-woven fabric for molding, if the non-woven fabric for molding is composed of only organic components, it does not stick during molding work and is excellent in workability, and it can be incinerated after use. This is because it is easy to dispose of.

The basis weight and thickness of the non-woven fabric for molding vary depending on the intended use and are not particularly limited. However, for example, when used as an exterior material for automobiles, the basis weight is excellent so as to have excellent sound absorption and rigidity. is preferably from 600~2800g / ^{m 2,} more preferably from 850~2500g / ^{m 2,} and even more preferably 1100~2100g / ^{m 2.} The thickness is preferably 3.2 to 11.0 mm, more preferably 4.25 to 8.9 mm, and even more preferably 4.3 to 6.8 mm.

Such a non-woven fabric for molding has, for example, a surface non-woven fabric layer on one side or both sides of the bulky non-woven fabric layer, and it is preferable that the bulky non-woven fabric layer and the surface non-woven fabric layer are adhered by an adhesive. This adhesive has a lower melting point than the resin component having the lowest melting point among the bulky non-woven fabric layer constituent fibers and the surface nonwoven fabric layer constituent fibers so as not to impair the porosity of the bulky nonwoven fabric layer and the surface nonwoven fabric layer. It is preferably 10 ° C. or higher, more preferably 20 ° C. or higher, still more preferably 30 ° C. or higher) resin (hereinafter, may be referred to as “adhesive resin”). On the other hand, if the melting point of the adhesive resin is too low, the heat resistance is lowered and the application application is limited. Therefore, the adhesive resin having a melting point of 80 ° C. or higher is preferable, and the adhesive resin having a melting point of 90 ° C. or higher is used. It is more preferable to have it.

Examples of such an adhesive resin include polypropylene, polyethylene (for example, high-density polyethylene and low-density polyethylene), polyvinyl chloride, polyamide, ethylene-vinyl acetate copolymer and the like. Among these, polypropylene is suitable because it has a low bonding temperature and excellent heat resistance. The adhesive resin may be of one type or two or more types.

Such an adhesive resin is preferably in a solid state so as to have excellent adhesiveness between the bulky non-woven fabric layer and the surface non-woven fabric layer. More specifically, the adhesive resin may have a powder shape, a fiber shape, or a fiber sheet shape such as a non-woven fabric, a woven fabric, or a net. Among these, the fiber sheet shape is preferable because it tends to be uniformly interposed between the bulky non-woven fabric and the surface non-woven fabric. If the adhesive resin is in the form of a film, the air permeability is lost and the sound absorption property is deteriorated. Therefore, the adhesive resin is preferably porous rather than in the film form.

The amount of such an adhesive resin is not particularly limited, but the bulky nonwoven fabric layer and the surface nonwoven fabric layer can be firmly adhered to each other, and the air permeability of the surface nonwoven fabric layer is not impaired. as the adhesive resin amount between the surface nonwoven layer and the bulky nonwoven fabric layer is preferably from 8~25g / ^{m 2,} more preferably from ^{10~20g / m 2, 12~18g / m} 2 Is more preferable. Therefore, if you have a surface nonwoven layer 2 layer, as a whole forming non-woven, weight adhesive resin is preferably a 16~50g / ^{m 2,} more preferably from 20 to 40 g / ^{m 2,.} 24 to It is more preferably 36 g / m ^2.

When such an adhesive resin is used, the melting point is equal to or higher than the melting point of the adhesive resin (preferably a temperature 10 ° C. higher than the melting point, more preferably the melting point) with the adhesive resin interposed between the bulky non-woven fabric and the surface non-woven fabric. At a temperature higher than 20 ° C., more preferably 30 ° C. higher than the melting point), the melting point is lower (preferably 10) than the resin component having the lowest melting point among the bulky non-woven fabric constituent fibers and the surface nonwoven fabric constituent fibers. The non-woven fabric for molding of the present invention can be produced by heating at a temperature (lower than ° C., more preferably 20 ° C. or higher, still more preferably 30 ° C. or higher) to melt the adhesive resin and then solidify it. .. When pressure is applied during heating or after heating, a non-woven fabric for molding can be obtained in which the bulky non-woven fabric layer and the surface non-woven fabric layer are firmly adhered.

Since such a non-woven fabric for molding of the present invention can achieve both sound absorption and rigidity, it can be applied to various uses. For example, it can be suitably applied to applications such as automobile exterior materials, automobile interior materials, partition applications, and wallpaper applications.

Since the exterior material for automobiles of the present invention is obtained by molding the above-mentioned non-woven fabric for molding of the present invention, it is excellent in both sound absorption and rigidity. The exterior material for automobiles of the present invention is formed into a desired shape such as a fender liner, an engine undercover, and a body undercover.

The molding method is not particularly limited, but for example, a method of heat-press molding with a pair of molds, a heating temperature after heating a molding non-woven fabric (for example, a hot air circulation heat treatment machine, a far-infrared heating device, etc.). There is a method of pressure molding with a pair of molds having a lower temperature.

Examples of the present invention will be described below, but the present invention is not limited to the following examples.

(Examples 1 to 5, Comparative Examples 1 to 4)
(1) Manufacture of surface non-woven fabric;
A raw polyester fiber (melting point: 256 ° C., fiber length: 51 mm) having a fineness of 1.6 dtex, 2.2 dtex, or 6.6 dtex, which was colored gray by kneading a pigment and was made of only polyester resin, was prepared. ..

Further, a raw polypropylene fiber (fineness: 4.4 dtex, fiber length: 51 mm, melting point: 165 ° C.) made of only homopropylene, which was colored black by kneading a pigment, was prepared.

Next, the original polyester fiber and the original polypropylene fiber are mixed at the mass ratios shown in Table 1, opened by a card machine to form a fiber web, and then cross-layered with respect to the production direction (longitudinal direction). , Fiber web constituent fibers were crossed to form a cross web. Then, a needle punch process was performed from one side of the cross web at a needle density of 200 needles / cm ² to manufacture a needle punch web.

Next, in Examples 1 to 5 and Comparative Examples 1 to 3, the needle punch web was supplied to a flat plate press machine and heated and pressurized under the conditions of ^{a temperature of 190 ° C. and a pressure of 30 kg / cm 2 to obtain the uncoated polypropylene.} Surface non-woven fabrics in which the original polyester fibers were fixed were produced by polypropylene-based resins in which the fibers were completely melted and solidified and stretched randomly and continuously.

On the other hand, in Comparative Example 4, the needle punch web was whipped and impregnated with an acrylic acid ester emulsion binder, dried at a temperature of 160 ° C., and then supplied to a flat plate press under the conditions of ^{a temperature of 190 ° C. and a pressure of 30 kg / cm 2.} A surface non-woven fabric in which the intersections of fibers were bonded with a binder was produced by heating and pressurizing with a binder. The basis weight and thickness of these surface non-woven fabrics are as shown in Table 2.

(2) Manufacture of bulky non-woven fabric;
On the other hand, an uncoated polyester fiber (melting point: 256 ° C.) having a fineness of 6.6 dtex and a fiber length of 51 mm, which was colored gray by kneading a pigment and was made of only polyester resin, was prepared.

In addition, a core-sheath composite heat-sealing fiber (fineness: 4.4 dtex, fiber length: 51 mm, core component melting point: 256 ° C., sheath component) containing low melting point polyester as a sheath component and polyethylene terephthalate as a core component. Melting point: 180 ° C., core component colored black with pigment) was prepared.

Next, the original polyester fiber and the core-sheath composite heat-sealing fiber are mixed at a mass ratio of 50:50, opened by a card machine to form a fiber web, and then produced by a cross layer (longitudinal). The fiber web constituent fibers were crossed with respect to the direction) to form a cross web. Then, a needle punch process was performed from one side of the cross web at a needle density of 200 needles / cm ² , and a needle punch web (weight: 1000 g / m ² ) was produced.

Then, the needle punch web is supplied to a hot air circulation furnace, hot air having a temperature of 200 ° C. is circulated, and then supplied to a flat plate press and pressurized under the conditions of ^{a temperature of 30 ° C. and a pressure of 20 kg / cm 2. A bulky non-woven fabric (grain: 1000 g / m 2} ) having a thickness of 5 mm, which was fused with the sheath component of the core-sheath type composite heat-sealing fiber, was produced.

(3) Preparation of adhesive;
As an adhesive between the surface non-woven fabric and the bulky non-woven fabric, a polypropylene spunbonded non-woven fabric (melting point: 165 ° C., basis weight: 15 g / cm ² , thickness: 0.17 mm) was prepared.

(4) Manufacture of non-woven fabric for molding;
The same surface non-woven fabric is laminated on both sides of the bulky non-woven fabric via a spunbonded non-woven fabric to form a five-layer laminate, which is then supplied to a flat plate press and pressurized under the conditions of a temperature of 190 ° C. and a flat plate interval of 5 mm. By completely melting and solidifying the spunbonded non-woven fabric, the surface non-woven fabric was adhered to both sides of the bulky non-woven fabric to manufacture the non-woven fabric for molding. The various physical characteristics of these non-woven fabrics for molding are as shown in Table 3. When the sound absorption coefficient of 1000 Hz and 2000 Hz of only the bulky non-woven fabric was measured, it was 0.08 and 0.19, respectively.

From the comparison between Examples 1 to 5 and Comparative Example 4, when the fibers are fixed by the polypropylene-based resin in which the surface nonwoven fabric layer is continuously stretched, the tensile elastic gradient of the surface nonwoven fabric layer is high and the rigidity is excellent, and as a result, the surface nonwoven fabric layer is excellent in rigidity. It was found that the non-woven fabric for molding has excellent rigidity.

Further, from the comparison between Examples 1 to 5 and Comparative Example 3, it was found that the rigidity of the non-woven fabric for molding is excellent when the tensile elastic gradient of the surface non-woven fabric layer is 150 N / mm or more.

Further, from the comparison between Examples 1 to 5 and Comparative Examples 1 to 3 and the comparison between Examples 1 to 5 and the bulky non-woven fabric, the air permeability was 0.1 to 4.0 ^{cm 3} / cm ² / sec. It was found that the non-woven fabric layer on the surface of the above material is excellent in sound absorption.

Further, from the comparison between Examples 2 and 4 and Examples 1, 3 and 5, the air permeability was 0.5 to 2.0 ^{cm 3} / cm ² / sec. It was found that the rigidity and sound absorption were particularly excellent.

Since the non-woven fabric for molding of the present invention has both sound absorption and rigidity, it can be suitably applied to, for example, automobile exterior materials, automobile interior materials, partitions, wallpaper and the like. In particular, the non-woven fabric for molding can be molded into a desired shape and suitably used as an exterior material for automobiles such as a fender liner, an engine undercover, and a body undercover.

Claims (5)

A non-woven fabric for molding having a surface non-woven fabric layer on one side or both sides of a bulky non-woven fabric layer having a thickness of 3 to 10 mm, and the surface non-woven fabric layer has fibers fixed by a continuously extending polypropylene-based resin and has a tensile elastic gradient. It is 150 N / mm or more and the air permeability is 0.1 to 4.0 ^{cm 3} / cm ² / sec. Of Ri Do from a nonwoven layer, wherein the a bulky nonwoven fabric layer and the surface nonwoven layer is bonded with polypropylene having a porous, molding nonwoven. The non-woven fabric for molding according to claim 1, wherein the non-woven fabric for molding has a flexural modulus of 350 MPa or more. The non-woven fabric for molding according to claim 1 or 2, wherein the fineness of the fibers constituting the surface non-woven fabric layer is 2.2 to 6.6 dtex. The non-woven fabric for molding according to any one of claims 1 to 3, wherein the non-woven fabric for molding comprises only an organic component. An automobile exterior material obtained by molding the non-woven fabric for molding according to any one of claims 1 to 4.

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