JP3073379B2 - Film for bonding automotive interior materials and automotive interior materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film used for bonding a base material for an automobile interior material and a decorative skin material such as a nonwoven fabric and an automobile interior material using the film. is there.

[0002]

2. Description of the Related Art Conventionally, as interior materials (interior ceiling materials) provided in an automobile interior, for example, an interior base material having various functions such as heat resistance, heat insulation, rigidity, sound absorption, moldability, and the like,
What has been molded by bonding an interior skin material having excellent moldability, abrasion resistance, aesthetic appearance, texture and the like and having air permeability is used.

[0003] The bonding of the base material and the skin material includes a step of applying an adhesive containing an organic solvent, a step of applying a hot-melt adhesive capable of bonding in a short time, and a heat-sensitive adhesive. A method including any step such as a step of thermocompression bonding via a film is often used. However, in particular, in the first two steps, the base material may not be formed by press molding and the skin may not be simultaneously bonded. Therefore, at least three steps are required: a step of first shaping the base material by press molding, a step of applying an adhesive to the base material, and a step of attaching a skin to the base material following the above-described step.

Further, when the base material to be used is a material having no air-blocking function, PVC or PBT which is expected to have only the air-blocking function for the purpose of providing the base material with the air-blocking function. A method of attaching a film such as the above to the back surface of the skin material, the front surface of the base material, the intermediate layer of the base material, or the back surface of the base material with an adhesive, a thermoplastic resin, or the like is often used.

[0005] If the substrate does not have a sufficient air blocking function, the following problems may occur.
That is, for example, during traveling of an automobile, due to a differential pressure generated between a vehicle interior, which is inside the interior material, and a body roof, which is outside the interior material, contamination in the vehicle interior including pollutants such as dust and cigarette smoke is caused. Air passes through the skin material and the base material and flows to the back side of the interior material, and contaminated air outside the vehicle compartment flows into the vehicle compartment. For this reason, the contaminants sometimes come into contact with and adhere to the surface of the skin material and become easily stained.

[0006]

[Problems to be solved by the invention]

(1) In the case of manufacturing an automobile interior material, when a skin material for interior having air permeability and a base material are heat-pressed with a heat roll or the like together with a heat-sensitive adhesive film interposed therebetween, the heat-sensitive material is used. The resin film that forms the heat-sensitive adhesive film is likely to collapse due to the melting of the adhesive film, the permeation of the melted part into the base material side, or the stretching and tearing of the film. It is difficult to obtain a stable air blocking function. (2) In addition, when manufacturing an automobile interior material having a complicated shape, the above three steps are performed in order to improve the productivity.
For the purpose of reducing the number of steps, the step of bonding the heat-sensitive adhesive film to the skin material for the interior is followed by two steps, namely, the step of bonding the surface of the heat-sensitive adhesive film to the base material for the interior. And the step of molding into the shape of the interior material can be performed simultaneously.

However, in this case, in the step of bonding the heat-sensitive adhesive film to the skin material, when the heat-sensitive adhesive film and the heat-sensitive adhesive film are pressure-bonded to each other in order to prevent a decrease in the air blocking property due to melting of the heat-sensitive adhesive film. If the amount of heat is suppressed, poor adhesion is likely to occur due to insufficient amount of heat. Conversely, if the amount of heat is applied to solve the poor adhesion, the heat-sensitive adhesive film not only impairs the air blocking function as an automobile interior material but also heats the heat roll. The problem of sticking to the pressure-bonded surface and remarkably reducing workability and processing efficiency was likely to occur. (3) Further, when the skin is bonded with a hot melt adhesive or the like, the adhesiveness is very liable to change due to changes in the amount of application, ambient temperature, temperature, etc., and it is very complicated and expensive to control them appropriately. It is not economical because it requires complicated equipment. In addition, since the reaction time of the adhesive is relatively long, high moldability of the skin is highly required, and if it is not satisfied, poor adhesion of the skin material is very likely to occur.

The present invention solves the above-mentioned problems, improves the efficiency of bonding the skin material and the base material, and can rationalize the bonding operation, and also bonds an automobile interior material having excellent air blocking properties and functions. It is intended to provide a film for use in automobiles and interior materials for automobiles.

[0009]

SUMMARY OF THE INVENTION The present inventor has proposed that the outer layer and the inner layer of a film use polyethylene resins having melting points and melt indices that are appropriately different from each other, thereby improving the heat-compression bonding with a skin material for an automobile interior. Adhesiveness and good adhesiveness at the time of thermocompression molding with the substrate are obtained, and by using a synthetic resin having a melting point higher than each of the polyethylene resins as the intermediate layer, the obtained interior material is air They have found that they exhibit excellent properties of barrier properties and have made the following invention. (1) The film for bonding automotive interior materials of the first invention is characterized in that the outer layer and the inner layer are made of a polyethylene resin, and the intermediate layer is made of a synthetic resin having a melting point higher than the polyethylene resin by 30 ° C. or more. .

Preferred embodiments 1 to 3 of the first invention are described below. That is, in the aspect 1, in the first invention, the outer layer has a melt index of 5.0 to 30.0 g / 10 m.
in, the inner layer has a melt index of 5.0 g / 10 mi
It is characterized by using a polyethylene-based resin of less than n. Embodiment 2 is characterized in that in Embodiment 1, the melting point of the polyethylene resin used for the inner layer is higher than the melting point of the polyethylene resin used for the outer layer by 10 ° C. or more.

[0011] Embodiment 3 is characterized in that in Embodiments 1 and 2, the synthetic resin of the intermediate layer is nylon or ethylene-vinyl alcohol copolymer resin. (2) In the automobile interior material of the second invention, the outer layer and the inner layer are made of a polyethylene resin, and the intermediate layer is made of a synthetic resin having a melting point higher than the polyethylene resin by 30 ° C. or more. The material and the base material are bonded to each other.

[0012] The laminating films (hereinafter referred to as films) of the first and second inventions each include an outer layer, an intermediate layer,
It is composed of three layers, the inner layer and the outer layer. The outer layer is bonded to the skin material of the interior material, and the inner layer is bonded to the base material of the interior material. Outer layer constituting the film, an intermediate layer,
Terms such as the inner layer do not indicate the position at the time of film production, but the outer layer indicates the film surface in contact with the skin material, and the inner layer indicates the film surface in contact with the base material.

The polyethylene resin used for the outer layer and the inner layer is not particularly limited as long as it has a heat-sensitive adhesive property. Examples of the polyethylene resin include low-density polyethylene, linear low-density polyethylene, and high-density polyethylene. Ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, ethylene-acrylic acid copolymer resin, ethylene-methyl acrylate copolymer resin, ethylene-methyl methacrylate copolymer resin, ethylene-methacrylic acid copolymer resin and blends thereof Things.

Particularly, the outer layer has a melt index (hereinafter referred to as MI) of 5.0 to 30.0 g / 10 mi.
It is preferable to use a polyethylene resin having an MI of less than 5.0 g / 10 min for the inner layer. In this case, since the heat fluidity of the inner layer in contact with the base material is lower than the heat fluidity of the outer layer in contact with the skin material, the resin in the inner layer melts on the heat-pressing roll or hot platen during bonding. Can be reduced, and workability and production efficiency can be improved. Moreover,
An automobile interior material having a stable adhesive force and a stable air blocking function can be obtained.

For these reasons, it is most preferable that the melting point of the polyethylene resin used for the inner layer is higher than the melting point of the polyethylene resin forming the outer layer by 10 ° C. or more. The synthetic resin used for the intermediate layer is not particularly limited as long as it is a synthetic resin having a melting point higher than that of the polyethylene resin used for the outer layer and the inner layer by 30 ° C. or more. It is particularly preferable to use nylon and ethylene-vinyl alcohol copolymer which is excellent in adhesiveness.

The film is formed by an inflation molding method, T
It can be manufactured by any of die casting methods,
The thickness is preferably 40 to 120 μm. The intermediate layer preferably has a thickness of 5 to 50 μm, particularly 1
Most preferably, the thickness is 0 to 30 μm. If the thickness of the intermediate layer is less than 5 μm, it may be locally stretched at the time of lamination molding and the like, and a hole may be formed, thereby impairing the air-blocking function. However, there are disadvantages such as high cost, uneconomical properties, and an increase in the amount of heat required during molding to deteriorate moldability.

The film can be bonded to various skin materials and base materials shown below, or the bonding and forming can be performed simultaneously. That is, the film can be attached to one surface as a skin material with high efficiency using, for example, a heating roll or the like, for example, a polyester-based nonwoven fabric, brushed knit, PVC leather, TPO leather, or the like.

Further, the film is obtained by laminating the skin material on one surface and then performing, for example, a needle punching process on the other surface as a base material, to at least one surface of a mat-like material mainly composed of inorganic fibers. Those having a thermoplastic resin film such as polyethylene, or those having a thermoplastic resin impregnated on at least one side, or those having a thermoplastic resin containing a foam material on at least one side,
Or, at least one surface of which has an inorganic fiber or a thermoplastic resin mixed with a filler, or a mat having a similar base material and the above-mentioned inorganic fiber as a main component instead of the above-mentioned mat-like material as a main component. A resin-like material impregnated with an emulsion-type adhesive, a foaming agent, or a thermoplastic resin, or a core material made of a resin foam such as urethane having a film layer mainly composed of a thermoplastic resin on at least one surface,
Further, a heat-cured resin, a thermoplastic resin, or a mat-like material mainly containing inorganic fibers impregnated with at least one kind of a foaming agent is hot-pressed together with the skin material bonded to the one surface. It is possible to manufacture and provide an automobile interior material having excellent air-blocking properties by performing hot pressing or simultaneously performing molding and bonding.

[0019]

The film for bonding automotive interior materials according to the first invention has an outer layer and an inner layer formed of a polyethylene resin, and an intermediate layer formed of three layers of a synthetic resin having a melting point higher than that of the polyethylene resin by 30 ° C. or more. I have. For this reason, the automotive interior material of the second invention obtained by bonding the skin material and the base material through the film has a surface portion where the outer layer is bonded to the skin material and a surface portion where the inner layer is bonded to the base material. Even when the intermediate layer is melted, the intermediate layer does not melt and maintains a sheet shape, so that the air blocking function of the intermediate layer itself and airtightness as an interior material can be maintained.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the film for bonding an automobile interior material of the first invention and the automobile interior material of the second invention will be described with reference to examples. Example 1 As shown in FIG. 1, a film for bonding automotive interior materials of Example 1 (hereinafter referred to as a film).
1A is manufactured by an inflation molding method, and is constituted by three layers formed of an outer layer 10a, an intermediate layer 11, and an inner layer 12, and has a total thickness of 75 μm (the outer layer 10, the intermediate layer 11 and the , The thickness ratio with the inner layer 12 is 2:
1: 2).

The outer layer 10 is a linear low-density polyethylene (MI: 0.8 g / 10 min, density: 30 μm).
0.919 g / cm ³ , melting point: 120 ° C.). The intermediate layer 11 is made of a nylon 6/66 copolymer having a thickness of 15 μm (relative viscosity: 4.2, density: 1.12 g / cm ³ , melting point: 200 ° C.). The inner layer 12 has a thickness of 30 μm
Linear low-density polyethylene (MI: 0.8 g / 10 m
in, density: 0.919 g / cm ³ , melting point: 120 ° C.)
Consisting of

The film 1A comprises an outer layer 10a and an inner layer 12
Then, an interior skin material 2 and an interior substrate 3 shown below, which are prepared in advance, are adhered to each other to manufacture an automobile interior material 4A. The skin material 2 is made of a polyester-based nonwoven fabric having a basis weight of about 170 g / m ² . The base material 3 has a basis weight of about 650 g / m ² obtained by impregnating both sides of a mat-like material obtained by needle-punching glass fibers and thermoplastic fibers with high-density polyethylene.
belongs to.

The skin material 2 comprises an outer layer 10a of the film 1A.
, And are superposed. Then, the skin material 2 and the film 1A are thermally bonded by a heat roll (not shown) having a surface temperature of about 130 ° C. to be integrated. The substrate 3 is placed on the inner layer 12 of the film 1A integrated with the skin material 2,
After the surface of the inner layer 12 was heated to about 170 ° C., an automobile interior material 4A was manufactured by press forming with a clearance of about 4 mm for 18 seconds using a not-shown forming die having a surface temperature of about 50 ° C.

An automobile interior material 4A obtained by using the film 1A of Example 1 and bonding the skin material 2 and the base material 3 through the film 1A has an outer layer 10a of the film 1A in which the skin material 2 Surface part and film 1 to adhere to
Even if the inner layer 12 of A melts at the surface portion where it adheres to the base material 3, the intermediate layer 11 does not melt and keeps a sheet-like shape, so that the intermediate layer 11 itself has an air blocking property and an air blocking function as the interior material 4A. Excellent in airtightness.

(Example 2) As shown in FIG. 1, a film (hereinafter referred to as a film) 4B for bonding an automobile interior material according to Example 2 is manufactured by an inflation molding method and includes an outer layer 10b. , An intermediate layer 11 and an inner layer 12
And the total thickness is 7
5 μm (the thickness ratio of the outer layer 10b, the intermediate layer 11, and the inner layer 12 is 2: 1: 2). The film 1B of Example 2 is the same except that the outer layer 10b is different from the outer layer 10a of the film 1A of Example 1 described above.

The outer layer 10b is a low-density polyethylene (MI: 13 g / 10 min, density: 0.9 μm) having a thickness of 30 μm.
19 g / cm ³ , melting point: 106 ° C.). As in the case of the film 1A of the first embodiment, the film 1B is formed by pressing the interior skin material 2 to the outer layer 10b and then the interior substrate 3 to the inner layer 12 at the same time as the film 1A of the first embodiment. Car interior material 4B was manufactured.

The automobile interior material 4B obtained by using the film 1B of Example 2 and bonding the skin material 2 and the base material 3 through the film 1B has an outer layer 10b of the film 1B in which the skin material 2 Surface part and film 1 to adhere to
(b) Even if the inner layer 12 melts at the surface portion where it adheres to the base material 3, the intermediate layer 11 does not melt and maintains a sheet-like shape, so that the intermediate layer 11 itself has an air-blocking property and an air-blocking function as the interior material 4B. Excellent in airtightness.

(Comparative Example) Here, the film 1A of Example 1 was used.
In order to confirm the effects of the automotive interior materials 3A and 3B manufactured using the film 1B of Example 2 and the film 1B of Example 2, respectively, a film for bonding automobile interior materials of Comparative Examples 1 and 2 (hereinafter, referred to as a film and a film) was used. Tables 1 to 8 show the characteristics and characteristic values of each interior material in the case where an automobile interior material was manufactured using the above-mentioned method and in the case of Example 1 and Example 2.

Table 1 shows the workability of bonding to the skin material.
Are shown in Table 2, the air barrier properties are shown in Table 2, the adhesiveness to the skin material is shown in Tables 3, 4, 5, and 6, and the hot adhesive retention between the film and the substrate after the forming press is shown in Table 7. Table 8 shows the flammability after press molding. (Comparative Example 1) In Comparative Example 1, a linear low-density polyethylene (MI: 0.8 g / 10 min, density: 0.919 g /
cm ³ , melting point: 120 ° C.)
A film for lamination with a thickness of μm was produced by an inflation molding method, and a skin material was adhered to one surface of the film under the same conditions as in Examples 1 and 2, and a substrate was adhered to the other surface and press-molded. At the same time to obtain the interior material.

Comparative Example 2 In Comparative Example 2, a high-density polyethylene (M) was used in which the intermediate layer was replaced with a nylon 6/66 copolymer.
I: 0.6 g / 10 min, density: 0.950 g / cm
³ , melting point: 129 ° C.), and a film having a total thickness of 75 μm (thickness composition ratio 2: 1: 2) was produced by inflation molding in the same manner as in Example 2. Under the same conditions as those described above, a skin material is adhered to one surface of the film, and a base material is adhered to the other surface and press molding is simultaneously performed to obtain an interior material.

[0031]

[Table 1] The case where the workability of laminating the film and the skin material was good was evaluated as ○, the case where it was slightly poor was evaluated as Δ, and the case where it was poor was evaluated as x.

[0032]

[Table 2] <Air-blocking property> The following numerical values indicate the amount of ventilation per minute in an area of 28 mm under a pressure of 40 KPa. In addition, the ventilation amount of Example 1, Comparative Example 1, and Comparative Example 2 is an average value of four samples each, and the ventilation amount of Example 2 is an average value of 38 samples.

[0033] Regarding dirt, ○ indicates that it was not observed, Δ indicates that it was slightly observed, and X indicates that it was clearly observed.

[0034]

<Table 3><Adhesiveness to skin material> Table 3 shows the evaluation when a peeling test was conducted at room temperature (23 ° C) after the film was bonded to the interior skin material by a hot roll. The case where the adhesive strength with the skin was sufficiently obtained was evaluated as “○”.

[0035]

<Table 4><Adhesiveness to substrate after forming press> Table 4 shows that after laminating a film to a skin material for interior by a hot roll, the film was further laminated and molded on a substrate for interior, Thereafter, the evaluation was performed when a peel test between the film and the substrate was performed at room temperature (23 ° C.).

[0036] The case where the adhesive strength with the base material was sufficiently obtained was evaluated as ○.

[0037]

[Table 5] <After thermal aging> Table 5 shows the evaluation when a peel test similar to the case of Table 4 above was performed after leaving in an atmosphere at 85 ° C for 400 hours. The case where the adhesive strength with the base material was sufficiently obtained was evaluated as ○.

[0038]

[Table 6] <After wet aging> Table 6 shows the evaluation when the same peel test as in the case of Table 4 above was conducted after leaving in an atmosphere at an atmospheric temperature of 50 ° C and a humidity of 90% for 400 hours. The case where the adhesive strength with the base material was sufficiently obtained was evaluated as ○.

[0039]

<Table 7><Hot adhesion retention with base material after forming press> Table 7 shows that the film is bonded to the interior skin material by a hot roll, and then this film is further laminated on the interior base material. Then, a constant load of 100 g is applied to the skin material side, and 85
This is an evaluation when a hot adhesion retention test between the film and the substrate was performed after leaving the film and the substrate in an atmosphere at 24 ° C. for 24 hours.

[0040] A case in which the hot adhesive holding property with the base material was sufficiently obtained was evaluated as ○.

[0041]

<Table 8><Combustibility after press forming> Table 8 shows that after laminating the film to the interior skin material by a hot roll, this film was further superimposed on the interior base material, and then subjected to a combustion test. It is an evaluation when performing. In addition, the combustion test
FMVSS No. Evaluation was performed according to the test method specified in 302, and the case where the standard was satisfied was evaluated as ○.

[0042]

【effect】

(1) The film for bonding an automobile interior material of the first invention is heated between an outer layer and an inner layer, and an outer layer and an inner layer, which are partially melted when heated and securely adhere to an interior skin material and a substrate. Since it is provided with an intermediate layer that does not melt even if it is heated, excellent air barrier properties can be maintained.

Further, according to the laminated film of the first invention, it is possible to obtain stable adhesiveness without impairing the air-blocking property when heat-pressing with a heat roller together with various interior skin materials. The workability at the time of pressure bonding is good and the bonding can be performed with high efficiency. Further, after the thermocompression bonding with the skin material, the material can be simultaneously formed and adhered to the substrate by a molding press or a thermoforming press, so that the molding process can be streamlined. (2) The automobile interior material of the second invention is a film of the first invention that retains the above-mentioned excellent air barrier properties, and an interior skin and a base material that are respectively bonded to the outer layer and the inner layer through the film. Therefore, the overall strength of the interior material can be improved, and excellent air blocking function and moisture blocking function can be obtained.

In the case of the automobile interior material of the second invention,
Even if the substrate is made of a material having no air-blocking function and having air permeability, a highly efficient and stable air-blocking function can be obtained by bonding and using the bonding film of the first invention to the substrate. Can be Therefore, according to the automobile interior material of the second invention, the contaminated air contaminated by dust and cigarette smoke in the vehicle interior and the contaminated air outside the vehicle interior do not permeate the interior material. It is possible to prevent the interior material from being stained due to transmission and contact with the interior material.

Further, according to the automobile interior material of the second invention,
Excellent productivity and no need to use an adhesive because it does not require a film that only expects an air blocking function, which is often used in conventional interior materials, or an adhesive application process dedicated to bonding the skin material Therefore, it is economical and can be made lighter than conventional interior materials.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view showing a cross-section of a main part of a vehicle interior material bonding film and a vehicle interior material in Examples 1 and 2 of the present invention.

[Explanation of symbols]

1A, 1B ... film for bonding 10a, 10b
... Outer layer 11 ... Middle layer 12 ... Inner layer 2 ... Skin material 3 ... Base material 4A, 4B ... Interior material

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hideki Uehara 2-9-3, Miyawaki-cho, Takamatsu-shi, Kagawa (56) References JP-A-3-69359 (JP, A) JP-A-2-86673 (JP) JP-A-2-43277 (JP, A) JP-A-9-85901 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B60R 13/02

Claims (5)

(57) [Claims] 1. A film for bonding automobile interior materials, wherein the outer layer and the inner layer are made of a polyethylene resin, and the intermediate layer is made of a synthetic resin having a melting point higher than the polyethylene resin by 30 ° C. or more. 2. An outer layer having a melt index of 5.0 to 3
0.0 g / 10 min. , The inner layer has a melt index of 5.0 g / 10 min. 2. The film for laminating an automobile interior material according to claim 1, wherein a polyethylene resin having a content of less than 1 is used. 3. The melting point of the polyethylene resin used for the inner layer is 10 ° C. lower than the melting point of the polyethylene resin used for the outer layer.
The film for bonding an automobile interior material according to claim 1 or 2, wherein the film is higher. 4. The film according to claim 1, wherein the synthetic resin of the intermediate layer is nylon or an ethylene-vinyl alcohol copolymer. 5. An outer layer and an inner layer are formed of a polyethylene resin, and an intermediate layer is bonded to a base material via a bonding film formed of a synthetic resin having a melting point higher than that of the polyethylene resin by 30 ° C. or more. An interior material for an automobile characterized by being made.