阅读说明：本技术 一种汽车前围消声零件及其制备方法 (Automobile front wall silencing part and preparation method thereof ) 是由 尤良军 张丛见 朱慧慧 于 2020-07-24 设计创作，主要内容包括：本发明提供了一种汽车前围消声零件及其制备方法,所述消声零件由外向内依次包括隔音层、粘结层和消音层,所述隔音层和消音层由复合纤维组成；所述复合纤维包括第一纤维和第二纤维,所述第一纤维的细度大于第二纤维的细度,所述第二纤维的长度为30～50mm,线密度为0.05～0.5dtex。本发明所述汽车前围消声零件中通过隔音层和消音层的设置,使其同时具备优异的吸声性能和隔声性能,尤其是采用超细纤维,使消音层能够形成疏松多孔结构,极大提高吸声性能,还能够通过超细纤维的振动消耗声能,提高吸声、隔声性能；本发明中超细纤维的使用能够降低零件的重量,实现汽车的轻量化。(The invention provides a front wall silencing part of an automobile and a preparation method thereof, wherein the silencing part sequentially comprises a sound insulation layer, a bonding layer and a silencing layer from outside to inside, and the sound insulation layer and the silencing layer are composed of composite fibers; the composite fiber comprises a first fiber and a second fiber, the fineness of the first fiber is larger than that of the second fiber, the length of the second fiber is 30-50 mm, and the linear density is 0.05-0.5 dtex. The automobile front wall noise elimination part has excellent sound absorption performance and sound insulation performance through the arrangement of the sound insulation layer and the noise elimination layer, particularly adopts superfine fibers, enables the noise elimination layer to form a loose porous structure, greatly improves the sound absorption performance, and can also consume sound energy through the vibration of the superfine fibers, and improves the sound absorption performance and the sound insulation performance; the use of the ultrafine fibers in the invention can reduce the weight of parts and realize the light weight of automobiles.)

1. The automobile front wall silencing part is characterized by sequentially comprising a sound insulation layer, a bonding layer and a silencing layer from outside to inside, wherein the sound insulation layer and the silencing layer are made of composite fibers;

the composite fiber comprises a first fiber and a second fiber, the fineness of the first fiber is larger than that of the second fiber, the length of the second fiber is 30-50 mm, and the linear density is 0.05-0.5 dtex.

2. The automotive cowl silencer component of claim 1,the sound insulation layer is characterized in that the gram weight of the sound insulation layer is 400-1000 g/m²The thickness is 2-8 mm;

preferably, the gram weight of the noise reduction layer is 600-1200 g/m²The thickness is 3-20 mm.

3. The automotive cowl louver part according to claim 1 or 2, characterized in that the first fibers include synthetic fibers and natural fibers;

preferably, the synthetic fibers comprise any one of polyester fibers, polyamide fibers or polyacrylonitrile fibers or a combination of at least two of the same;

preferably, the natural fibers comprise cotton fibers;

preferably, the length of the first fiber is 30-80 mm, and the linear density is 4-8 dtex.

4. The automotive dash muffling part of any one of claims 1 to 3, wherein the second fibers comprise any one of or a combination of at least two of polypropylene fibers, polyester fibers, polyamide fibers, or polyacrylonitrile fibers;

preferably, the composite fibers of the sound insulation layer and the sound attenuation layer comprise, in mass fraction: 15-30% of synthetic fibers, 45-75% of natural fibers and 10-25% of second fibers.

5. The automobile front wall silencing part according to any one of claims 1 to 4, wherein the material of the bonding layer comprises any one or a combination of at least two of polypropylene, polyethylene, polyamide, polyester or polyvinyl chloride;

preferably, the gram weight of the bonding layer is 20-60 g/m²。

6. The method for manufacturing an automotive cowl silencer component according to any one of claims 1 to 5, characterized by comprising the steps of:

(1) preparing the first fibers and the second fibers into flat felt to form a sound insulation layer and a sound attenuation layer;

(2) placing the sound insulation layer flat felt in the step (1) in a flat mold, adjusting the temperature, the pressure and the gap of a gasket, closing the mold and maintaining the pressure, and adjusting the thickness of the sound insulation layer;

(3) and placing the sound-absorbing layer, the bonding layer and the sound-absorbing layer with the adjusted thickness in a steam flat plate die in sequence, vacuumizing, filling steam, adjusting the temperature, the pressure and the gap of the gasket, and carrying out pressure maintaining forming to obtain the automobile front wall flat plate sample.

7. The manufacturing method according to claim 6, wherein the flat felt of step (1) is manufactured by an air-laying method;

preferably, the first fibers and the second fibers in the step (1) are proportioned according to corresponding mass fractions;

preferably, the soundproof layer and the sound-deadening layer obtained in the step (1) have a loose porous structure.

8. The preparation method according to claim 6 or 7, characterized in that the temperature of the mold during the mold closing and pressure maintaining in the step (2) is 120-180 ℃;

preferably, the pressure of the die is 3-8 MPa when the die is closed and maintained in the step (2);

preferably, the gap between the gaskets in the step (2) is 2-8 mm during die assembly and pressure maintaining;

preferably, the time for closing and maintaining the mold in the step (2) is 50-90 s;

preferably, after the mold closing and pressure maintaining in the step (2), the soundproof layer is cooled.

9. The production method according to any one of claims 6 to 8, wherein the sound-deadening layer, the adhesive layer and the sound-deadening layer after thickness adjustment or the sound-deadening layer after thickness adjustment, the adhesive layer and the sound-deadening layer are sequentially placed in the steam flat mold in the step (3) from bottom to top;

preferably, the steam flat plate die in the step (3) is vacuumized after being closed, and the vacuum pressure is-0.08 to-0.01 MPa;

preferably, the vacuum holding time in the step (3) is 5-30 s.

10. The production method according to any one of claims 6 to 9, wherein the mold temperature in the pressure maintaining molding in the step (3) is 150 to 200 ℃;

preferably, the pressure of the die in the pressure maintaining molding in the step (3) is 5-15 MPa;

preferably, the gap between the gaskets during pressure maintaining molding in the step (3) is 5-30 mm;

preferably, the pressure maintaining forming time in the step (3) is 30-150 s;

preferably, after the pressure maintaining molding in the step (3), opening the mold and cooling to obtain the automobile front wall panel sample.

Technical Field

The invention belongs to the technical field of processing of automotive interior parts, and relates to an automotive front wall noise elimination part and a preparation method thereof.

Background

With the development of social economy, the use of automobiles is more and more popular, and the performance requirements of consumers on the automobiles are higher and higher, so that the automobiles are used as a vehicle and pay more attention to the driving experience. The automobile noise is an important standard for measuring the performance of an automobile, the generation of the automobile noise is mainly transmitted from an automobile engine to an automobile cab, the noise transmission path is controlled for reducing the noise, and the automobile front wall is a part between the engine cab and a passenger cab, has important contribution to improving the driving comfort and has good sealing, vibration isolation and sound insulation effects, so the automobile front wall is made of sound insulation and noise reduction materials.

In the traditional method, the automobile front wall part usually adopts a sound insulation pad structure, the material selection of the sound insulation pad structure is usually combination of an EVA surface layer and a foaming layer bottom layer, the sound insulation pad of the structure has the advantages of complex manufacturing process, lower sound absorption and noise reduction effects and poor environmental protection performance, and needs to be improved and optimized. In the existing cognition, the sound absorption and sound insulation performance of the material are opposite, namely, the requirements of the sound absorption and sound insulation performance on the same characteristic of the material are opposite, and one material has good sound absorption performance and poor sound insulation performance, or has good sound insulation performance and poor sound absorption performance.

CN 203485853U discloses a two-component automotive front wall sound-proof felt capable of being formed, which comprises a sound absorption layer and a sound insulation layer, wherein the sound absorption layer is made of fluffy low-density three-dimensional multi-gap fiber knitted felt, the sound insulation layer is made of high-density fiber knitted felt, the sound insulation layer and the sound absorption layer are compositely bonded by PE (polyethylene) lamination, the sound insulation layer and the sound absorption layer are mainly improved on the aspects of large smell, large weight and the like of the traditional sound insulation felt, and are also improved and designed on the opposite performances of sound absorption and sound insulation, but the selection of fiber materials of the sound insulation felt is not clear, and the sound insulation and noise reduction performances are limited.

At present, the dash structure materials on the market also adopt low-melting-point fibers, cotton fibers and the like, and CN107599564A discloses a preparation method of a PET/PP composite sound-absorbing material, wherein the preparation method comprises the steps of melt spinning of a PET/PP mixture, steam die preforming, cooling and sizing, water cutting, packaging and warehousing, a sound-insulating pad is formed by compounding multiple layers of sound-absorbing materials, and the sound-insulating pad comprises an outer centrifugal cotton mesh surface, an intermediate layer of activated carbon fiber mesh surface and an inner PET/PP composite mesh surface so as to achieve a better sound-absorbing effect, but the composite fibers do not relate to the aspect of fineness, so that the sound-absorbing performance of the product is difficult to effectively improve, and the composite sound-absorbing material mainly improves the sound-absorbing performance and does not relate to the improvement of the sound-insulating performance.

In summary, for the structural design and material selection of the front wall noise elimination part of the automobile, the requirement of simultaneously having the sound absorption and sound insulation performance, especially effectively improving the sound absorption performance, and realizing the lightweight of the front wall part is also met.

Disclosure of Invention

The automobile front wall noise elimination part has sound absorption performance and sound insulation performance through the arrangement of the sound insulation layer and the noise elimination layer, particularly, the inner hole structure of the noise elimination layer can be greatly increased due to the addition of superfine fibers, so that the sound absorption performance is improved, the weight of the noise elimination part can be reduced, and the light weight of the automobile part is realized.

In order to achieve the purpose, the invention adopts the following technical scheme:

on one hand, the invention provides a front wall silencing part of an automobile, which sequentially comprises a sound insulation layer, a bonding layer and a silencing layer from outside to inside, wherein the sound insulation layer and the silencing layer are composed of composite fibers;

the composite fiber comprises a first fiber and a second fiber, the fineness of the first fiber is larger than that of the second fiber, the length of the second fiber is 30-50 mm, and the linear density is 0.05-0.5 dtex.

According to the automobile front wall noise elimination part, the sound isolation layer and the sound elimination layer are arranged and are tightly combined through the bonding layer, so that the sound absorption layer and the sound elimination layer have excellent sound absorption performance and sound insulation performance, wherein the sound elimination layer is made of superfine fibers, namely the fineness of the fibers is small, pores in the material can be increased, a loose porous structure is formed, the specific surface area is large, more viscous loss is generated after sound waves enter, sound energy is converted into heat energy, and the sound absorption performance is greatly improved; when the superfine fibers are adopted, the smaller the fiber fineness is, the lighter the fiber mass per unit quantity is, and when the superfine fibers are exposed in positive and negative sound pressure waves, the lighter fibers can vibrate more easily to convert sound energy into mechanical energy and heat energy; the noise elimination part can promote the driving experience, can reduce the weight of part again, realizes the lightweight of car, reduces the oil consumption, makes contributions for energy saving and emission reduction.

Wherein the length of the second fiber is 30 to 50mm, such as 30mm, 32mm, 35mm, 38mm, 40mm, 42mm, 45mm, 48mm or 50mm, but not limited to the recited values, and other values not recited in the range of the recited values are also applicable; the linear density is 0.05 to 0.5dtex, such as 0.05dtex, 0.1dtex, 0.15dtex, 0.2dtex, 0.25dtex, 0.3dtex, 0.4dtex or 0.5dtex, but not limited to the recited values, and other values not recited in the numerical range are also applicable.

The following technical solutions are preferred technical solutions of the present invention, but not limited to the technical solutions provided by the present invention, and technical objects and advantageous effects of the present invention can be better achieved and achieved by the following technical solutions.

As a preferable technical scheme of the invention, the gram weight of the sound insulation layer is 400-1000 g/m²E.g. 400g/m²、500g/m²、600g/m²、700g/m²、800g/m²、900g/m²Or 1000g/m²And the like, but are not limited to the recited values, and other unrecited values within the numerical range are equally applicable; the thickness is 2 to 8mm, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm or 8mm, but the thickness is not limited to the values listed, and other values not listed in the numerical range are also applicable.

Preferably, the gram weight of the noise reduction layer is 600-1200 g/m²E.g. 600g/m²、700g/m²、800g/m²、900g/m²、1000g/m²、1100g/m²Or 1200g/m²And the like, but are not limited to the recited values, and other unrecited values within the numerical range are equally applicable; the thickness is 3 to 20mm, for example, 3mm, 5mm, 8mm, 10mm, 12mm, 15mm, 18mm or 20mm, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.

According to different functions of the sound insulation layer and the sound attenuation layer, the sound insulation layer mainly plays a sound insulation role, needs to be controlled to be thick through a die pressure, belongs to a hard layer and is small in thickness, and the sound attenuation layer mainly plays a sound absorption role, is of a loose porous structure and is relatively large in thickness.

As a preferred embodiment of the present invention, the first fibers include synthetic fibers and natural fibers.

Preferably, the synthetic fibers comprise any one of polyester fibers, polyamide fibers or polyacrylonitrile fibers, or a combination of at least two of these, typical but non-limiting examples being: a combination of polyester fibers and polyamide fibers, a combination of polyamide fibers and polyacrylonitrile fibers, a combination of polyester fibers, polyamide fibers and polyacrylonitrile fibers, and the like.

In the invention, the synthetic fiber belongs to the fiber types commonly used at present, and the three polyester fibers PET, the polyamide fiber PA and the polyacrylonitrile fiber PAN are sequentially polyester fiber, polyamide fiber and acrylic fiber.

Preferably, the natural fibers comprise cotton fibers.

Preferably, the first fibers have a length of 30 to 80mm, such as 30mm, 40mm, 50mm, 60mm, 70mm, or 80mm, but not limited to the recited values, and other values not recited within the range of values are equally applicable; the linear density is 4 to 8dtex, such as 4dtex, 4.5dtex, 5dtex, 5.5dtex, 6dtex, 6.5dtex, 7dtex, 7.5dtex or 8dtex, but not limited to the recited values, and other values not recited within the range of values are also applicable.

In the invention, the main difference between the first fiber and the second fiber is only the difference of the linear density, namely the fiber fineness of the first fiber and the fiber fineness of the second fiber are different, and the fibers with different fineness are matched, so that a structural layer with better sound absorption performance can be obtained.

As a preferred embodiment of the present invention, the second fiber includes any one of polypropylene fiber, polyester fiber, polyamide fiber, or polyacrylonitrile fiber, or a combination of at least two of them, and the combination is exemplified by, typically but not limited to: combinations of polypropylene fibers and polyester fibers, combinations of polyester fibers and polyamide fibers, combinations of polyamide fibers and polyacrylonitrile fibers, combinations of polypropylene fibers, polyamide fibers and polyacrylonitrile fibers, and the like.

Preferably, the composite fibers of the sound insulation layer and the sound attenuation layer comprise, in mass fraction: 15-30% of synthetic fibers, such as 15%, 18%, 20%, 22%, 25%, 27%, or 30%, but not limited to the recited values, and other values not recited within the range of values are also applicable; 45-75% of natural fibers, such as 45%, 50%, 55%, 60%, 65%, 70%, or 75%, but not limited to the recited values, and other values not recited within the range of values are also applicable; 10-25% of the second fibers, such as 10%, 12%, 15%, 18%, 20%, 22%, or 25%, but not limited to the recited values, and other values not recited within the recited range are equally applicable; the sum of the mass fractions of the three fibers is 100%.

According to the invention, the mass fraction of the second fibers has an obvious influence on the structures and performances of the sound insulation layer and the sound insulation layer, if the mass fraction of the second fibers is too low, the sound absorption and insulation performance is not obviously improved due to the limited number of internal pores, and if the mass fraction of the second fibers is too high, the structural layer of the whole part is loose, and the mass fraction of the first fibers is too low, so that the sound absorption and insulation effect cannot be achieved.

As a preferred embodiment of the present invention, the material of the adhesive layer includes any one or a combination of at least two of polypropylene, polyethylene, polyamide, polyester, and polyvinyl chloride, and typical but non-limiting examples of the combination include: combinations of polypropylene and polyethylene, combinations of polyethylene and polyamide, combinations of polyethylene and polyvinyl chloride, combinations of polyamide, polyester and polyvinyl chloride, and the like.

Preferably, the gram weight of the bonding layer is 20-60 g/m²E.g. 20g/m²、25g/m²、30g/m²、35g/m²、40g/m²、45g/m²、50g/m²、55g/m²Or 60g/m²And the like, but are not limited to the recited values, and other values not recited within the numerical range are also applicable.

In the invention, the bonding layer is mainly used for tightly combining the sound insulation layer and the noise reduction layer, so that the sound insulation layer and the noise reduction layer are prevented from being separated from each other under the action of external force or from being provided with gaps to influence the noise reduction performance.

In another aspect, the invention provides a method for preparing the automobile front wall noise elimination part, which comprises the following steps:

(1) preparing the first fibers and the second fibers into flat felt to form a sound insulation layer and a sound attenuation layer;

(2) placing the sound insulation layer flat felt in the step (1) in a flat mold, adjusting the temperature, the pressure and the gap of a gasket, closing the mold and maintaining the pressure, and adjusting the thickness of the sound insulation layer;

(3) and placing the sound-absorbing layer, the bonding layer and the sound-absorbing layer with the adjusted thickness in a steam flat plate die in sequence, vacuumizing, filling steam, adjusting the temperature, the pressure and the gap of the gasket, and carrying out pressure maintaining forming to obtain the automobile front wall flat plate sample.

As a preferable technical scheme of the invention, the flat felt in the step (1) is prepared by an air-laying method.

According to the invention, the flat felt is prepared by adopting the fibers in an air-laid manner, wherein the air-laid manner is that different fibers are respectively added into respective pre-opening machines according to a certain proportion for preliminary opening and dispersion, then all the fibers enter the fine opening machines for fine opening and mixing, then the mixed fibers enter a high-position cotton bin for full mixing, then enter a lapping machine for lapping and forming through odor, and finally the fibers are heated and cooled and shaped through an oven.

Preferably, the first fibers and the second fibers in the step (1) are proportioned according to corresponding mass fractions.

Preferably, the soundproof layer and the sound-deadening layer obtained in the step (1) have a loose porous structure.

In a preferred embodiment of the present invention, the mold temperature in the step (2) is 120 to 180 ℃, for example, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃ or 180 ℃, but the present invention is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.

Preferably, the mold pressure in the clamping and pressure maintaining step (2) is 3 to 8MPa, for example, 3MPa, 4MPa, 5MPa, 6MPa, 7MPa or 8MPa, but the values are not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the gap between the gaskets in the clamping and pressure maintaining processes in step (2) is 2-8 mm, such as 2mm, 3mm, 4mm, 5mm, 6mm, 7mm or 8mm, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the clamping and pressure maintaining time in the step (2) is 50 to 90s, such as 50s, 55s, 60s, 65s, 70s, 75s, 80s, 85s or 90s, but not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, after the mold closing and pressure maintaining in step (2), the soundproof layer is cooled, taken out, and subjected to a cooling process to be cooled to room temperature.

In the invention, the operation of the structure of the sound insulation layer is adjusted according to the function of the sound insulation layer in the step (2), the thickness of the sound insulation layer is controlled through hot die forming, and the performance of the sound insulation layer for reflecting sound waves is improved through controlling the film thickness, namely the sound insulation performance is further improved.

As a preferable technical scheme of the invention, the sound-deadening layer, the adhesive layer and the sound-deadening layer after the thickness is adjusted or the sound-deadening layer, the adhesive layer and the sound-deadening layer after the thickness is adjusted are sequentially arranged in the steam flat plate mold in the step (3) from bottom to top.

Preferably, the steam flat plate mold in step (3) is closed and then evacuated to a vacuum pressure of-0.08 to-0.01 MPa, for example, -0.08MPa, -0.07MPa, -0.06MPa, -0.05MPa, -0.04MPa, -0.03MPa, -0.02MPa or-0.01 MPa, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the vacuum holding time in step (3) is 5 to 30s, such as 5s, 10s, 15s, 20s, 25s or 30s, but not limited to the recited values, and other values not recited in the range of values are also applicable.

In a preferred embodiment of the present invention, the mold temperature in the pressure-holding molding in the step (3) is 150 to 200 ℃, for example, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃ or 200 ℃, but the present invention is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.

Preferably, the mold pressure in the pressure-holding molding in the step (3) is 5 to 15MPa, for example, 5MPa, 6MPa, 8MPa, 10MPa, 12MPa or 15MPa, but the pressure-holding molding is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.

Preferably, the gap between the gaskets in the pressure maintaining molding in the step (3) is 5 to 30mm, for example, 5mm, 10mm, 15mm, 20mm, 25mm or 30mm, but not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.

Preferably, the dwell pressure forming time in the step (3) is 30 to 150s, such as 30s, 40s, 50s, 60s, 80s, 100s, 120s or 150s, but not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, after the pressure maintaining molding in the step (3), opening the mold and cooling to obtain the automobile front wall panel sample.

Compared with the prior art, the invention has the following beneficial effects:

(1) the automobile front wall noise elimination part has excellent sound absorption performance and sound insulation performance through the arrangement of the sound insulation layer and the noise elimination layer, particularly adopts superfine fibers, enables the noise elimination layer to form a loose porous structure, greatly improves the sound absorption performance, and can also consume sound energy through the vibration of the superfine fibers, and improves the sound absorption performance and the sound insulation performance;

(2) the sound insulation layer is controlled to be thick through the die pressure, the density of the sound insulation layer is increased, and therefore the performance of the sound insulation layer for reflecting sound waves is improved, namely the sound insulation performance of the sound insulation layer is further improved;

(3) the use of the ultrafine fibers in the invention can reduce the weight of parts and realize the light weight of automobiles.

Drawings

FIG. 1 is a comparison graph of sound absorption performance of a front wall sound-deadening part for an automobile provided in example 1 of the present invention and that provided in comparative example 1;

fig. 2 is a comparison graph of sound insulation performance of the automobile front wall sound-deadening part provided in example 1 of the present invention and that of comparative example 1.

Detailed Description

In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the present invention, which is defined by the claims.

The invention provides a front wall noise elimination part of an automobile and a preparation method thereof, wherein the noise elimination part sequentially comprises a sound insulation layer, a bonding layer and a noise elimination layer from outside to inside, and the sound insulation layer and the noise elimination layer are composed of composite fibers;

the composite fiber comprises a first fiber and a second fiber, the fineness of the first fiber is larger than that of the second fiber, the length of the second fiber is 30-50 mm, and the linear density is 0.05-0.5 dtex.

The following are typical but non-limiting examples of the invention: