JP4361202B2 - Sound-absorbing material including meltblown nonwoven fabric - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sound absorbing material comprising a fiber assembly including a melt blown nonwoven fabric.
[0002]
[Prior art]
Conventionally, single-layer organic and inorganic fiber aggregates are often used as sound-absorbing materials contained in automobile engine rooms and home appliances. These fiber aggregates have the function of absorbing and attenuating the generated noise, but the effect is not always sufficient and is often unsatisfactory. In addition, there is a sound-absorbing material composed of two or more fiber aggregates having a surface layer of an ultrafine fiber layer having a very small apparent density, but has a drawback that the sound-absorbing property is not necessarily good.
[0003]
[Problems to be solved by the invention]
The present invention is intended to solve the above-described problems, and an object of the present invention is to provide a novel sound-absorbing material that is excellent in heat resistance and that is remarkably excellent in noise-absorbing performance and surface wear resistance. Is.
[0004]
[Means for Solving the Problems]
As a result of various studies on the above problems, the present inventor found that the meltblown nonwoven fabric having a specific apparent density and the constituent fibers accumulated in a planar shape and other fiber aggregates are in a flat state of the meltblown nonwoven fabric. It has been found that the sound-absorbing performance is dramatically improved and the above-mentioned problems can be solved by joining and integrating while maintaining. Melt blown non-woven fabrics have low surface wear resistance, so there are practical problems depending on the application, but as a solution, polyester spunbond non-woven fabric with excellent wear strength and heat resistance is coated on one or both sides. It has been found that the practical performance is further improved by making it disposed on the outermost surface, and the present invention has been completed.
[0005]
That is, the present invention has an apparent density of 0.1 to 0.1 in which fine fibers made of a mixture of 80% by mass to 20% by mass of polyethylene terephthalate and 20% by mass to 80% by mass of polybutylene terephthalate are substantially planarly integrated. ~0.4g / cm ^3, and melt-blown nonwoven fabric having a basis weight 5~300g / m ^2, and at least composed of polyester fibers of single fiber fineness 1~11dtex on one basis weight 10 to 100 g / m ² spunbond nonwoven of the nonwoven fabric The melt blown nonwoven fabric has a laminated body having a thickness of 5 to 50 mm, and the melt blown nonwoven fabric has no entanglement or opening by needle punch, and the adhesive portion between the melt blown nonwoven fabric and the spunbond nonwoven fabric has a heat embossed area of 50%. A sound-absorbing material characterized in that it is heat-bonded in the following and the spunbonded nonwoven fabric is disposed on the outermost surface. is there.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The melt blown nonwoven fabric used for the sound absorbing material of the present invention has an average fiber diameter of 10 μm or less produced by a melt blown method from a mixture of 80% by mass to 20% by mass of polyethylene terephthalate and 20% by mass to 80% by mass of polybutylene terephthalate. It is important that the fibers are made of fibers and the constituent fibers are accumulated substantially in a plane.
Although it is possible to obtain a nonwoven fabric having an average fiber diameter exceeding 10 μm by the melt blown method, a melt blown nonwoven fabric having an average fiber diameter exceeding 10 μm cannot achieve the object of the present invention.
More preferably, it is desired to use a melt blown nonwoven fabric made of fibers having an average fiber diameter of 2 μm to 8 μm.
[0007]
The resin used in the present invention is a mixture of polyethylene terephthalate and polybutylene terephthalate. A melt blown nonwoven fabric made only of polyethylene terephthalate shrinks by 40% when treated in a drying furnace at 120 ° C., for example, and does not have sufficient heat resistance. On the other hand, a meltblown nonwoven fabric containing only polybutylene terephthalate does not adhere to a polyester spunbond nonwoven fabric that is easily available in the city by thermal calendering or hot embossing. However, 80% to 20% by mass of polyethylene terephthalate and 20% to 80% by mass of polybutylene terephthalate are mixed and melt blown to provide excellent heat resistance and easily bonded to a polyester spunbond nonwoven fabric by thermocompression bonding. A meltblown nonwoven fabric is obtained. When the mixing ratio is outside this range, a melt blown nonwoven fabric that satisfies both heat resistance and adhesiveness at the same time cannot be obtained.
[0008]
The apparent density of the melt blown nonwoven fabric used in the present invention needs to be in the range of 0.1 to 0.4 g / cm ³ . When the apparent density is less than 0.1 g / cm ³ , the sound absorption effect is significantly impaired. On the other hand, if the apparent density exceeds 0.4 g / cm ³ , the sound absorbing effect is reduced, which is not preferable.
[0009]
Basis weight of the meltblown nonwoven fabric is preferably in the range of 5~300g / m ² is preferably in the 10 to 100 g / m ^2. When the basis weight is less than 5 g / m ² , a sufficient sound absorbing effect cannot be exhibited when the fiber aggregate on the inner surface is joined and integrated. On the other hand, if the basis weight exceeds 300 g / m ² , the cost increases and the utility is lacking.
[0010]
Furthermore, in the sound-absorbing material of the present invention, the meltblown nonwoven fabric is accumulated in a planar shape on a collection surface such as an accumulation net in the nonwoven fabric production process, and the fibers are hardly arranged in the three-dimensional direction. The resulting melt-blown nonwoven fabric made of ultrafine fibers generally has low surface wear strength, so when used as it is as a surface layer of a sound-absorbing material, the fibers are worn away by cutting or the like due to friction during handling or use. The role as a meltblown nonwoven is lost.
[0011]
In order to compensate for such drawbacks, the present inventors have found that it is extremely effective to coat one or both sides of a melt blown nonwoven fabric using a polyester spunbond nonwoven fabric having excellent wear strength. That is, by disposing a spunbond nonwoven fabric made of polyester fiber having a basis weight of 10 to 100 g / m ² and a single fiber fineness of 1 to 11 dtex on the surface of the meltblown nonwoven fabric, the surface wear strength is remarkably improved and the sound absorbing performance of the sound absorbing material is improved. It is maintained for a long time.
Furthermore, the polyester spunbonded nonwoven fabric has a melting point of 200 ° C. or higher, which is a desirable material from the viewpoint of heat resistance.
[0012]
It is desirable to bond the meltblown nonwoven fabric and the polyester spunbond nonwoven fabric by hot embossing or thermal calendaring. When bonding by a hot embossing calendar, the embossed area is desirably 50% or less, particularly 15% or less. This is because the embossed portion is usually easily formed into a film, and the film portion of such a melt-blown nonwoven fabric has a lower sound absorption effect than the fiber portion, so it is desirable that the amount is as small as possible.
[0013]
The sound-absorbing material of the present invention is obtained by laminating a polyester spunbonded nonwoven fabric on at least one surface of the meltblown nonwoven fabric, and is used as a sound-absorbing material so that the spunbonded nonwoven fabric side is on the outermost surface. May be laminated on the other surface of the meltblown nonwoven fabric as needed, if necessary.
[0014]
In this case, organic or inorganic natural fibers or synthetic fibers can be appropriately used as the fiber aggregate of the base layer. This fiber web can be produced by a dry method such as a spunbond method or a card method, or a wet method using papermaking. The fiber web prepared by such a method can be applied to various means such as resin bonding by impregnation or spraying, heat melting bonding by fusing fiber, mechanical entanglement such as needle punching or water entanglement, and combinations thereof. Are combined into a fiber assembly. However, the preferred form is not one in which fibers are entangled three-dimensionally, such as needle punching or water entanglement, but a fiber assembly in which the fibers are accumulated as flat as possible is preferred.
The apparent density of the fiber assembly is preferably 0.01 to 0.10 g / cm ³ and the basis weight is preferably 30 to 2000 g / m ² . If the apparent density is less than 0.01 g / cm ^3, the rigidity for supporting the meltblown nonwoven fabric may be insufficient, and the entire sound absorbing material may be deformed. On the other hand, if it is greater than 0.10 g / cm ^{3, the} sound absorption characteristics may deteriorate. Similarly, when the basis weight is less than 30 g / m ² , the result of the rigidity is insufficient, which is not preferable. On the other hand, if the basis weight exceeds 2000 g / m ² , the rigidity becomes too large, and it becomes difficult to process the laminate.
[0015]
The base layer, the meltblown nonwoven fabric and the polyester spunbond nonwoven fabric are preferably integrated by bonding. For the joining, a resin adhesive such as hot melt, an adhesive net or powder, a fusion fiber, or the like is mainly used, but the number of superposed layers in this case is not particularly limited. As long as the melt blown nonwoven fabric, the base fiber aggregate, and the polyester spunbonded nonwoven fabric are in a range that satisfies the conditions of the basis weight and the thickness of the sound absorbing material specified in the present invention, specific usage modes such as the required level of sound absorbing performance Depending on the situation, not only one layer but also two or more layers may be laminated as required.
[0016]
It should be noted that mechanical entanglement means such as a needle punch should be avoided as much as possible in the interlayer bonding between the melt blown nonwoven fabric and the fiber assembly. With such a means, the opening of the dense meltblown nonwoven fabric is caused by the action of the needles penetrating each other. Further, the constituent fibers of the meltblown nonwoven fabric accumulated in a planar shape are rearranged three-dimensionally by the action of the above means. These two points both have a very bad influence on the sound absorption and insulation performance. Therefore, it is necessary to join the layers so as not to damage the two-dimensional fiber arrangement of the meltblown nonwoven fabric as much as possible.
[0017]
The overall thickness of the sound absorbing material of the present invention is 5 to 50 mm. When the thickness is less than 5 mm, a sufficient effect on the sound absorbing performance cannot be obtained, which is not preferable. In addition, when the thickness exceeds 50 mm, it is preferable in terms of sound absorption performance, but when used as a sound absorbing material, the installation space becomes excessive, which is undesirable in terms of product design, and is not preferable because it is difficult to handle in terms of processing such as cutting and molding. Providing excessive performance is also uneconomical.
[0018]
The sound absorbing material of the present invention obtained in this way is excellent in heat resistance and sound absorbing performance such as noise, and as a sound absorbing material included in an engine room of a vehicle such as an automobile or a home appliance, It can be used for building wall coverings, house wraps, etc.
[0019]
【Example】
EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
[0020]
Example 1 and Comparative Example 1
A melt blown nonwoven fabric having a weight per unit area of 35 g / m ^{2 made} of a polymer blend having a blending ratio of polybutylene terephthalate / polyethylene terephthalate of 60/40 was prepared. This nonwoven fabric had an average fiber diameter of 4.2 μm and an apparent density of 0.25 g / cm ³ . Next, a spunbonded nonwoven fabric having a basis weight of 20 g / m ² made of polyester fiber having a single fiber fineness of 6.2 dtex was prepared, laminated on the surface of the meltblown nonwoven fabric, and both were partially bonded using an embossed calendar. The embossed area in the hot embossed calendar adhesion by this dot-like pattern was 4.1%.
[0021]
Next, 40% by mass of a polyester fiber having a cut length of 51 mm at 13 dtex, 45% by mass of a polyester fiber having a cut length of 40 mm by 3.3 dtex, and a copolymer polyester having a polyethylene terephthalate as a core component and a softening point of about 170 ° C. as a sheath component We were prepared two kinds of card web having a mass per unit area of 200 g / m ² and basis weight 265 g / m ² of composite polyester fibers 15% by weight of 2.2dtex to.
Next, a card web having a basis weight of 200 g / m ² was subjected to heat fusion processing through a dryer at 180 ° C. The apparent density was 0.017 g / cm ³ .
Subsequently, the surface of this nonwoven fabric is laminated with a polyamide melt-bonded net having a basis weight of 10 g / m ² , the melt blown nonwoven fabric, and the polyester spunbond nonwoven fabric in this order, and is passed through a heating roll as it is to be fused and joined to form a unit weight of 265 g. A fiber laminate of / m ² was obtained.
[0022]
The obtained basis weight 265 g / m ² of fiber laminate (Example 1, thickness 13 mm) nonwoven (Comparative Example 1, thickness 15 mm) was obtained by heat-treating and the card web aforementioned basis weight 265 g / m ² When the sound absorption performance was examined by the reverberation chamber method sound absorption rate measurement method of JIS A1409, the former showed about 30% in the latter 1000 Hz region and about 50% better in 3000 Hz, and an excellent sound absorbing material. It turned out to be. Moreover, this sound-absorbing material was also excellent in surface wear strength, and it was found that there was no problem in practical durability.
[0023]
Example 2
Polyester composite fiber having a single fiber fineness of 13 dtex and a cut length of 51 mm of polyester fiber of 38% by mass, a single fiber fineness of 3.3 dtex and a cut length of 51 mm of polyvinyl alcohol fiber of 50% by mass, and the single fiber fineness of 2.2 dtex used in Example 1 A card web comprising 12% by mass was prepared, and the web was treated with hot air to obtain a felt having a weight of 15 mm and a basis weight of 250 g / m ² .
On the other hand, the laminate nonwoven fabric of the melt blown nonwoven fabric and the polyester spunbond nonwoven fabric used in Example 1 was used, and an ethylene-vinyl acetate hot melt adhesive was applied to the melt blown nonwoven fabric surface at a rate of 30 g / m ² by the sinter method.
Next, the felt and the meltblown nonwoven fabric were laminated so that the hot melt adhesive application surface was in the middle, and both were adhered by a thermal calendar. The obtained laminate had a thickness of 14 mm and excellent sound absorption performance and surface wear strength similar to those of Example 1.
[0024]
【The invention's effect】
Unlike the conventional sound absorbing material, the sound absorbing material of the present invention includes at least one melt-blown nonwoven fabric having a specific apparent density and basis weight, and therefore has excellent sound absorbing performance. Moreover, since the polyester spunbond nonwoven fabric excellent in abrasion resistance is arranged on the surface of the melt blown nonwoven fabric, it is excellent in practicality such as durability.

Claims (4)

Apparent density of 0.1 to 0.4 g / cm in which fine fibers made of a mixture of 80% by mass to 20% by mass of polyethylene terephthalate and 20% by mass to 80% by mass of polybutylene terephthalate are substantially integrated in a planar shape. ^3, a basis weight 5~300g / m and ² melt blown nonwoven fabric, thickness 5 to which the spunbonded nonwoven fabric of at least a polyester fiber of a single fiber fineness 1~11dtex on one side of the basis weight 10 to 100 g / m ² nonwoven fabric are laminated This melt blown nonwoven fabric has no entanglement or opening by needle punch, and the bonded portion between the melt blown nonwoven fabric and the spunbond nonwoven fabric is thermally bonded with a heat embossed area of 50% or less. A sound-absorbing material , wherein the spunbonded nonwoven fabric is disposed on the outermost surface. A vehicle using the sound absorbing material according to claim 1. An electrical product using the sound absorbing material according to claim 1. A wall covering made of the sound absorbing material according to claim 1.