JPH04194065A - Automobile interior material for forming and its production - Google Patents

Abstract

PURPOSE:To obtain the subject interior material having light weight, small thermal deformation ratio and excellent formability by integrating a skin fiber layer and a substrate fiber layer by needle-punching, thereby forming a high- density region having a high apparent density and a reverse-side low-density region having low apparent density in the substrate fiber layer. CONSTITUTION:A fiber web for skin fiber layer and a fiber web for substrate fiber layer are integrated by needle-punching from the side of the fiber web for skin fiber layer to give a gradient of the fiber density, decreasing from the fiber web for skin fiber layer to the fiber web for substrate fiber layer. A synthetic emulsion is impregnated into the fiber web for substrate fiber layer from the side of the fiber web for substrate fiber layer to obtain the objective forming interior material for automobile, composed of a skin fiber layer and a substrate fiber layer integrated with each other by needle-punching. The substrate fiber layer is composed of a high-density region having high apparent density and a low-density region having low apparent density and positioned at the reverse surface side of the interior material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molded automobile interior material and a method for manufacturing the same. More specifically, the present invention relates to a molded box automobile interior material that can be suitably used as an automobile interior material that requires molding with a large space ratio, such as a trunk room or a tire space cover, and a method for manufacturing the same.

[Prior Art] Conventionally, interior materials for automobiles have been made by integrating a skin material and a rigid base material such as resin felt through a Snowtanbond nonwoven fabric made of heat-fusible filaments. There is. However, when the above-mentioned automobile interior materials are deep-drawn, the base material acts as a resistance, so it is not possible to form sharply along the mold, and the degree of elongation between the skin material and the base material is insufficient. Since the difference is large, there is a problem that peeling occurs between the two.

In addition to the above-mentioned automobile interior materials, a fiber web for the skin fiber layer and an edge fiber web for the base material containing heat-sealable fibers were laminated and needle punched from the side of the fiber web for the skin fiber layer. Later, automobile interior materials that were heated and integrated were proposed. However, such automobile interior materials
When deep-drawing is performed, the fiber web for the base fiber layer acts as a resistance, resulting in large dimensional changes and deformations after forming.Moreover, the shape is maintained by the heat-fused fibers, resulting in poor thermal stability. There is a problem with it being bad.

[Problems to be Solved by the Invention] In view of the above-mentioned prior art, the present inventors have developed a method that has excellent formability and that does not cause peeling between the skin material and the base material even when deep drawing is performed. As a result of intensive research into creating an automobile interior material that does not cause molding and retains its shape after molding,
We have finally found an automobile interior material that satisfies all of these physical properties, and have completed the present invention.

[Means for Solving the Problems] That is, the present invention provides: (1) a skin fiber layer and a base fiber layer are integrated by needle punching, and the base fiber layer has a high-density region with a high apparent density; An automobile interior material for molding, comprising a low-density region with a low apparent density, and the low-density region is on the back side of the interior material; By needle punching the fiber web from the fiber web side for the skin fiber layer, the fibers are integrated so that the fiber density decreases from the fiber web side for the skin fiber layer to the fiber web side for the base fiber layer. The present invention relates to a method for manufacturing an automobile interior material for molding, which comprises impregnating a fiber web for a base fiber layer with a synthetic resin emulsion from the fiber web side for a fiber layer.

[Function and Examples] As described above, the automobile interior material of the present invention is produced by needle-punching the fiber web for the skin fiber layer and the fiber web for the base fiber layer from the fiber web side for the skin fiber layer. After integrating so that the density becomes smaller from the fiber web side for the skin fiber layer to the fiber web side for the base fiber layer, the synthetic resin emulsion is applied from the fiber web side for the base fiber layer to the fiber web for the base fiber layer. Obtained by impregnation.

The fibers forming the fiber web for the skin fiber layer used in the present invention are not particularly limited, but include, for example, synthetic fibers such as polyester, polyamide, polyolefin, and acrylic; recycled fibers such as rayon; and natural fibers such as wool. Among these, polyester spun-dyed fibers and polypropylene spun-dyed fibers are particularly preferred because they have excellent weather resistance, light resistance, and abrasion resistance.

In addition, the fiber web for the skin fiber layer contains 5 to 40% (weight %, hereinafter the same) of heat-fusible fibers to suppress fluff.
It is preferable that the content is about <10 to 15%. Examples of the heat-fusible fibers include conjugate fibers made of polyester/low melting point polyester, polyester/polyethylene, etc.; conjugate fibers made of polypropylene/polyethylene, fibers made of polypropylene, etc. These fibers are usually used alone. Or a mixture of two or more types may be used.

If the basis weight of the fiber web for the skin fiber layer is too small, the skin fiber layer formed will become thin and the base fiber layer will be visible through it, resulting in a decrease in quality as an interior material. If the ratio is too large, the extensibility of the resulting interior material tends to be too small;
~300g/m Nkanzu<80~180g/
Preferably, it is m2.

Examples of the fibers forming the fiber web for the base fiber layer used in the present invention include synthetic fibers such as polyester, polyamide, polyolefin, and acrylic; recycled fibers such as rayon; and natural fibers such as cotton and wool. Among these, polyester fibers are particularly preferred because they have excellent weather resistance, light resistance, and abrasion resistance.

In addition, since the fiber web for the base fiber layer does not appear on the surface,
In order to reduce costs, B-tangle wires or curled wires may be used. Here, B-tangle refers to non-standard cotton fibers generated during the production of synthetic fibers, and recombinant fiber refers to the fibers that have been cut and re-fibrillated into leather yarn or cloth.

In addition, among the fibers forming the fiber web for the base fiber layer, thermal adhesive fibers are present in an amount of 0 to 50%, especially 0 to 30%.
%, but in this case, it is desirable that the heat-adhesive fibers be included in a high-density region where the rigidity necessary to maintain the shape after molding is required, and to alleviate the distortion caused by molding. , it is desirable not to be included in low-density regions that would allow sharp deformation along the mold.

If the basis weight of the fiber web for the base fiber layer is too small, it will lack the rigidity necessary to keep the shape of the molded product stable when used for molding, and if it is too large, it will lack the rigidity necessary to keep the shape of the molded product stable when used for molding. However, the total weight of the molded product tends to be large, which goes against the purpose of reducing the weight of the car and makes it unsuitable as an automobile interior material.
/I11, Nakadzu<150-500g/hall 2 is preferable.

In addition, when the fiber web for the base fiber layer is impregnated with the synthetic resin emulsion, in order to collect more of the synthetic resin emulsion on the side closer to the fiber web for the skin fiber layer, the fiber for the skin fiber layer is impregnated with the fiber web for the skin fiber layer. It is necessary to increase the fiber density on the side closer to the web and lower it on the side that will become the back surface of the resulting interior material. When used as an automobile interior material for molding, a highly rigid, high-density region is formed on the side of the base fiber layer near the skin fiber layer, and a highly flexible low density region of fibers is formed on the back side of the interior material. This is to form a dense region. The high-density region of the seven layers of base fibers has the function of giving the resulting interior material the rigidity necessary to maintain its shape after molding, while the low-density region absorbs distortion during molding and provides the interior material with the necessary rigidity to maintain its shape after molding. It has the function of making it easier for the material to conform to the mold.

Therefore, when integrating the fiber web for the skin fiber layer and the fiber web for the base fiber layer, needle punching is performed from the fiber web side for the skin fiber layer, thereby adjusting the fiber density from the fiber web side for the skin fiber layer. It becomes smaller toward the fiber web side for the base fiber layer.

There are no particular limitations on the conditions for the needle punch, but the needle density is usually 50 to 500 needles/cm2, and <
The number of needles is preferably 100 to 300 needles/cm2, and the depth of the needles is preferably such that the fiber web layer for the base fiber layer is penetrated.

After the fiber web for the skin fiber layer and the fiber web for the base fiber layer are integrated by needle punching, the surface of the fiber web for the base fiber layer is impregnated with a synthetic resin emulsion.

Examples of the synthetic resin emulsion include emulsions of polystyrene resins, styrene-butadiene copolymers, styrene-butadiene-acrylonitrile copolymers, acrylic ester-styrene copolymers, etc. The solid content is not particularly limited, but is usually about 20 to 60%.

The amount of the synthetic resin emulsion adhered is usually 50 to 400 g/m2 in terms of solid content after drying, and <10 g/m2.
It is adjusted to be 0 to 250 g/+n2.

The solid content of this thermoplastic resin emulsion is 5.
If it is less than 0g/m2, the resulting interior material will not have sufficient rigidity, and molded products using it will have poor shape retention, and if it exceeds 400g/m2, the resulting interior material will not have sufficient rigidity. The entire interior material becomes hard and heavy, which tends to make it difficult to form sharply along the mold.

The synthetic resin emulsion is adjusted so that it impregnates only the fiber web for the base fiber layer and does not substantially impregnate the fiber web for the skin fiber layer. For example, when impregnating one side of a fiber web while squeezing a synthetic resin emulsion between rolls, the thickness of the impregnated layer can be adjusted by changing the viscosity of the synthetic fiber emulsion or the distance between the rolls, and the synthetic resin Prevent the emulsion from impregnating into the fiber web for the skin fiber layer. However, in reality, the synthetic resin emulsion may be impregnated to some extent into the fiber web for the skin fiber layer, so it is sufficient that the synthetic resin emulsion does not impregnate the vicinity of the surface of the fiber web for the skin fiber layer.

In this way, when the synthetic resin emulsion is impregnated from the fiber web side for the base fiber layer, the synthetic resin emulsion is transferred to the skin fiber web layer side, which has a higher density, due to capillary action. A large amount of it adheres to the high-density region, and as a result, a high-density layer is formed inside the resulting interior material, especially in the approximately central portion, resulting in excellent rigidity.

In addition, when the impregnated synthetic resin emulsion reaches the surface of the fiber web layer for the skin fiber layer,
Particular care must be taken when impregnating, as the texture of the surface will deteriorate.

After that, a drying process is performed to evaporate the water content of the synthetic resin emulsion, and if the fiber web contains heat-adhesive fibers, the heat-adhesive fibers are thermally bonded. Automotive interior materials for molding can be changed.

The automobile interior material for molding of the present invention obtained as described above includes a skin fiber layer consisting of a fiber web for the skin fiber layer, and a base fiber layer in which a synthetic resin is attached to the fiber web for the base fiber layer. It has an integrated structure using needle punching. Then, on the skin fiber layer side of the base fiber layer, a high-density region is formed in which a layer with high fiber density is impregnated with a large amount of synthetic resin, and on the back side of the interior material, a layer with low fiber density is formed. A low density region impregnated with a small amount of synthetic resin is formed.

Note that it is difficult to accurately measure the apparent density of each of the high-density region and low-density region of the skin fiber layer and base fiber layer because the density changes gradually because each layer is integrated by needling. Although it is difficult, for example, by cutting and separating the parts that are considered to be the interfaces of each layer with a cutter knife, etc.
When calculated from the weight and thickness of each layer, the apparent density of the skin fiber layer is 0.02~D, 17g/cm3, <
0.04-0.151/cm", the high-density region of the base fiber layer is 0.05-0.2 (Ig/cm2, <0.09-0.17 g/cm3, the base fiber layer The low density region is 0.01~0.05g/c-1<0.0
1~G, 04g/cn+'' is desirable.

In addition, it is desirable that the skin fiber layer is not substantially impregnated with synthetic resin in order to have a soft texture, so even if the fiber density is higher in the skin fiber layer than in the high-density area, the apparent density is It is preferable that the skin fiber layer has a lower density, and on the other hand, in view of moldability, it is preferable that the low density region has a lower apparent density than the skin fiber layer even if it is impregnated with a synthetic resin.

As described above, the automotive interior material for molding of the present invention has a bulky and low apparent density region in the base fiber layer, so even when deep drawing is performed with a high deformation rate, Since the low-density region of the base fiber layer absorbs the strain caused by molding, it is possible to perform molding with a clean finish without wrinkles or the like. In addition, in the present invention, since the base fiber layer has a highly rigid, high-density region in which a large amount of synthetic resin is attached, a molded product with excellent shape retention and no deformation during molding can be obtained. .

Next, the automotive interior material for molding of the present invention and its manufacturing method will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

Example 1 A web made of recycled wool mainly composed of polyester fibers (fabric weight = 200 g/+n2) as a fiber web for the base fiber layer
A web consisting of 85% spun-dyed polyester fibers and 15% conjugate fibers made of polyester/low melting point polyester was applied as a fiber web for the skin fiber layer on this web (
Area weight + 10,077m2) were piled up.

Next, needle punch (needle density: 300 pieces/cm2, needle depth: 12 mm) from the fiber web side for the skin fiber layer.
) to entangle and integrate the fiber web for the base fiber layer and the fiber web for the skin fiber layer.

A styrene-butadiene-acrylonitrile copolymer emulsion (solid content: 4o%) was added to the fiber web layer for the skin fiber layer and the fiber web layer for the base fiber layer from the fiber web side for the base fiber layer of the obtained laminate. While adjusting to impregnate up to the boundary, the amount of solid content after drying is 00g/m2
After being impregnated so that

The obtained automotive interior material for molding has a skin fiber layer and a base fiber layer, and the base fiber layer has a high-density region on the skin fiber layer side and a low-density region on the back side of the interior material. A region was formed. When the high-density region and the low-density region of the skin fiber layer and the base fiber layer were cut and separated using a cutter knife and the apparent density of each was measured, it was found that the skin fiber layer was 0.0.
6g/cm, 0.12g/cm"' in high density areas
, and in the low density region it was 0.021/crn3.

The boundary between the high-density region and the low-density region is not clear, but if there is a clear change in density, you can check the area, or if it is not clear, check the thickness of the base fiber layer. Approximately 172 locations were cut as boundaries. In this example, since there was a portion where the change in density was thickened, the sample was cut at that portion as a boundary.

In addition, the physical properties of the obtained automobile interior material for molding were examined for lightness, bending hardness, rigidity, 20% modulus, moldability, heat deformation rate, and heat resistant shape retention according to the following methods.

The results are shown in Table 1.

(a) The weight (basis weight) per lll12 of the automobile interior material for molding that has achieved lightweight properties is measured, and evaluated based on the following evaluation criteria.

(Evaluation criteria) ◎: Weight of interior material is less than 700g ○: Weight of interior material is 700g or more and less than 900g △: Weight of interior material is 900g or more and less than 1200g ×: Weight of interior material is 1200g or more (b) Even bending hardness After heating the molded automobile interior material for 3 minutes at 180°C, it was cold-pressed with a space of 4 mm for 20 minutes.
℃, 30kg/cm2), thickness 4non, length 25
mm, width g Qmm test piece, span interval 54m
The maximum bending strength was measured according to ASTM D-790 at a bending speed of 20 mm/min, and the value was taken as the bending hardness.

(c) Rigidity The bending hardness per unit weight obtained by dividing the above bending hardness by the basis weight of the automobile interior material for molding is defined as the stiffness. Note that the rigidity is evaluated based on the following evaluation criteria.

(Evaluation criteria) ◎ 20.7 or more ○: 0.3 to 0.7 △: 0.2 to 0.3 100m
1+), the distance between chucks is 50 mm, and the pulling speed is 5.
The stress (kg) at 20% elongation is determined by pulling at 0 mm/min.

(E) Formability After heating the moldable automobile interior material at 180°C for 3 minutes,
A mold is used to form a hemispherical convex portion with a diameter of 90 mm, and the boundary line between the hemisphere and the plane is observed and evaluated based on the following evaluation criteria in addition to the 20% modulus.

(Evaluation criteria) ◎: The boundary line is clear, and the 20% modulus is [1,6
Less than kg ○: The boundary line is clear and the 20% modulus is 0.6k
g or more and less than 2.0 kg △: The boundary line is unclear and the 20% modulus is 2.0
kg or more and less than 4.0 kg×: The border line is unclear,
After heating an automobile interior material for thermal deformation molding with a 20% modulus of 4.0 kg or more at 180°C for 3 minutes,
The molded product was molded to form a hemispherical convex portion with a diameter of 90 mm, and the resulting molded product was left in a constant temperature heater at 90° C. for 5 hours, and the height of the hemisphere before and after that was measured to determine the deformation rate. The deformation rate is the difference in the height of the hemisphere before and after heating the molded product at a constant temperature,
The value is expressed as a percentage (%) divided by the height of the hemisphere before heating.

(g) Thermal shape retention The thermal shape retention is determined by evaluating the thermal deformation rate based on the following criteria. The smaller the thermal deformation rate, the better the thermal shape retention.

(Evaluation criteria) Less than 020.5% ○: 0.5% or more to less than 2% ×: 2% or more Example 2 In Example 1, the basis weight of the fiber web for the base fiber layer was 2.
An automobile interior material for molding of the present invention was obtained in the same manner as in Example 1, except that the solid content of the synthetic resin emulsion was 125 g/m2, and the total weight was 500 g/m2. The apparent density of each layer of the obtained automobile interior material for molding was the same as in Example 1.

In addition, the physical properties of the obtained automobile interior material for molding were investigated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 As a fiber web for the base fiber layer, 70% composite fibers made of polyester/low melting point polyester and 30% polyester fibers were placed on a web made of recycled fibers mainly composed of polyester fibers (fabric weight: 29 Qg/m2). Naru Web (
A web (fabric weight: 390 g/m2) formed by laminating fibers (fabric weight: 100 g/m2) was used, and composite fiber 15 consisting of 85% spun-dyed polyester fibers and polyester/low melting point polyester was used as a fiber web for the skin fiber layer on this web.
% webs (fabric weight: 100 g/m2) were overlapped.

Next, needle punch from the fiber web side for the skin fiber layer (needle density: 300 pieces/cm", needle depth: 12 mm)
The fiber web for the base fiber layer and the fiber web for the skin fiber layer were entangled and integrated.

A styrene-acrylic copolymer emulsion (solid content: 40
%) was adjusted to be impregnated up to the boundary between the fiber web layer for the skin fiber layer and the fiber web layer for the base fiber layer, and impregnated so that the amount of solid content after drying was 100 g/m2, A heat treatment was performed for 5 minutes in a hot air dryer at +5[1°C] to obtain an automobile interior material for molding of the present invention.

The apparent density of the skin fiber layer of the obtained automotive interior material for molding is 0.06 g/cm'', the apparent density of the high-density region of the base fiber layer is 0.14 g/cm3, and the apparent density of the base fiber layer is 0.14 g/cm3. The apparent density of the low density region was 0.02 g/C-.

In addition, the physical properties of the obtained automotive interior material for molding are shown in Example 1.
I investigated in the same way. The results are shown in Table 1.

Comparative Example 1 Polyester fiber web (fabric weight: 2110
The needle density of 250 needles/cIn2 was applied to the polystyrene resin emulsion to a solid content of 50. Needle punch felt with backing to give g/m2 (basis weight 250g/m2)
prepared.

On the other hand, as a base material, resin felt (700 P/m'') was prepared by impregnating 75% felt made of natural fibers and waste cotton as constituent fibers with 25% styrene-acrylic copolymer emulsion.

After that, the skin material and the base material are bonded together using a hot melt resin mainly composed of ethylene-vinyl acetate copolymer.
An automobile interior material for molding was obtained by adhering at 40°C.

The physical properties of the obtained automobile interior material for molding were investigated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 Needle punch felt (fabric weight: 150 g/m2) prepared by needling a polyester fiber web at a needle density of 200 needles/cm2 was prepared as a skin material, and on the other hand,
Composite fiber 3 consisting of 65% recycled wool mainly made of polyester fiber and polyester/low melting point polyester as the base material
Needle punch felt (fabric weight: 650 g/m2) was prepared by applying two-links to a fiber web consisting of 5% needles at a needle density of 50 needles/cm2.

After this, the skin material and the base material are combined at a needle density of 200 needles/c.
An automobile interior material for molding was obtained by integrating by needling under the conditions of 2.

The physical properties of the obtained automobile interior material for molding were investigated in the same manner as in Example 1. The results are shown in Table 1.

[Margins below] As is clear from the results shown in Table 1, the automotive interior materials for molding obtained in Examples 1 to 3 of the present invention were the same as those obtained in Comparative Examples 1 to 3.
It can be seen that it is lighter than the conventional moldable automobile interior material obtained in step 2, and has a small 20% modulus both vertically and horizontally, making it possible to mold along a mold and having excellent moldability. In addition, the molded automobile interior materials obtained in Examples 1 to 3 have good rigidity and low thermal deformation rate, so it can be seen that the deformation of the molded product obtained by molding is extremely small.

[Effects of the invention] The automobile interior material for molding of the present invention is lightweight, has a small modulus, and has excellent moldability, and also has good rigidity and has a small thermal deformation rate even when hot molded. For example, it can be suitably used for automobile trunk rooms, tire space covers, etc.

Claims (1)

[Claims] 1. A skin fiber layer and a base fiber layer are integrated by needle punching, and the base fiber layer consists of a high-density region with a high apparent density and a low-density region with a low apparent density. Become,
An automobile interior material for molding, characterized in that the low-density region is on the back side of the interior material. 2 By needle punching the fiber web for the skin fiber layer and the fiber web for the base fiber layer from the fiber web side for the skin fiber layer, the fiber density changes from the fiber web side for the skin fiber layer to the fiber web side for the base fiber layer. 1. A method for manufacturing an automobile interior material for molding, which comprises: integrating the fiber web so as to make it smaller, and then impregnating the fiber web for the base fiber layer with a synthetic resin emulsion from the side of the fiber web for the base fiber layer.