JPH06115024A - Automobile interior finishing material - Google Patents

Abstract

PURPOSE:To obtain a material having a soft and flexible feeling when being pressed and superior cushioning properties and never emitting malodor at a high temperature by laminating a polypropylene resin sheet, a foaming-in-place polyolefin resin sheet, and a foaming-in-place polypropylene resin body in order. CONSTITUTION:A polypropylene resin sheet 1 and a foaming-in-place polypropylene resin sheet 2 having a high expansion ratio are melted under heat to be made into an integral laminate. This laminate is attached to a mold so that the resin sheet is in contact with a molding flat surface having no vapor hole. In a pressureproof container, an internal pressure of 2kg/cm<2>.G is previously applied by air to pre-expanding polypropylene resin particles for forming a foaming-in-place polypropylene resin body 3 having a low expansion ratio. The pre-expanded polypropylene resin particles are charged into the mold.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an automobile interior material. More specifically, for example, automotive door materials, sun visors, ceiling materials, door trims, rear packages, knee bolsters, airbag doors, headrests, armrests, various pillars, quarter trims, front side trims, front seat backs, crash pads, consoles. Automotive interior materials such as boxes, console lids, luggage floor covers, partition boards, center consoles, and console box lids.

[0002]

2. Description of the Related Art Conventionally, as an interior material for automobiles, a leather sheet such as polyvinyl chloride, a foam sheet such as polypropylene foam, and a core material such as ABS resin are sequentially polymerized, and are integrally formed by using an adhesive. It is known that the bound laminate is heated and softened and then pressure-molded by a molding die.

However, although the interior material for automobiles has a foam sheet, it has the drawbacks that it has a hard feel when pressed, is inferior in cushioning property, and has a poor weight feeling.

As a material capable of eliminating the drawbacks of the interior materials for automobiles, a leather sheet made of polyvinyl chloride, a foam sheet such as polypropylene foam, a polyurethane foam layer and a core material such as ABS resin are sequentially laminated, Integrated laminates are known.

Since the laminate has a polyurethane foam layer in the intermediate layer, a soft feel is certainly imparted when pressed, and the cushioning property is improved as compared with the automobile interior material. However, its weight is larger than that of the interior material for automobiles, and there is a drawback that a bad odor based on polyvinyl chloride is emitted at a high temperature and a harmful gas is generated at the time of combustion.

Further, in recent years, in the automobile industry, in order to improve the fuel efficiency of automobiles, it has been strictly demanded to reduce the weight of parts constituting the automobile, and as a part thereof, further reduction in weight has been achieved. The development of automobile interior materials and automobile interior materials that are easy to recycle from the viewpoint of reusing resources is highly desired.

[0007]

Therefore, the present inventors have found that
In view of the above-mentioned conventional technology, a soft and supple feel is imparted when pressed, excellent cushioning properties, good weight feeling, no bad odor at high temperature, and a small amount of harmful gas generated during combustion, As a result of intensive research to develop an automobile interior material that can satisfy many requirements such as weight reduction and easy recycling, a completely new automobile interior material that can satisfy all of these requirements at the same time. Finally, the present invention was completed.

[0008]

That is, the present invention comprises a polypropylene resin sheet, a polyolefin resin in-mold foam sheet having a high expansion ratio, and a polypropylene resin in-mold foam having a low expansion ratio, which are sequentially laminated. Car interior materials.

[0009]

OPERATION AND EXAMPLE The interior material for automobiles of the present invention, which does not require a core material made of ABS resin or the like, which has been required in the prior art, has a significantly improved weight saving. It was done. The present invention eliminates the need for such a core material in view of the characteristics of the interior material for automobiles, in view of the mechanical properties required for the interior material for automobiles, particularly the compressive strength and the bending strength. It is based on the fact that the polypropylene resin in-mold foam has a sufficient amount.

Further, in the automobile interior material of the present invention, when pressed, the polyolefin resin in-mold foam sheet having a high expansion ratio formed on the back surface of the polypropylene resin sheet forming the skin is first soft. The polypropylene resin in-mold foam having a low expansion ratio formed on the back surface of the polyolefin resin in-mold foam sheet, which gives a feeling, is slightly harder than the in-mold foam sheet, but is made of a conventional resin. To give a very soft feeling in comparison with the core material, that is, to give a so-called two-step soft feeling, and to give a soft and supple feeling to fingers and the like that come into contact with the automobile interior material of the present invention. Due to
This gives the automobile interior material a solid feeling and a high-class feeling.

Further, as described above, the automobile interior material of the present invention absorbs two impacts: the polyolefin resin in-mold foam sheet having a high expansion ratio and the polypropylene resin in-mold foam having a low expansion ratio. Since it has a layer capable of controlling, it has an excellent buffering property.

Further, in the conventional interior materials for automobiles of the present invention, since the leather sheet mainly made of polyvinyl chloride is used for the outer skin, the temperature inside the automobile reaches a high temperature such as in summer. Although a nasty odor was sometimes emitted, the problem of odor at a high temperature was solved because a substrate that generates such a bad odor was not used.

Furthermore, the automobile interior material of the present invention comprises:
Since the base material that constitutes this is made of a polyolefin resin, it is easy to recycle it, and it causes harm to the human body such as hydrocyanic acid gas, which is said to be generated when polyurethane foam is burned. It has the property that no harmful gas is generated and the amount of gas that is harmful to the human body is small.

As described above, the interior material for automobiles of the present invention comprises a polypropylene resin sheet, a polyolefin resin in-mold foam sheet having a high expansion ratio, and a polypropylene resin in-mold foam material having a low expansion ratio, which are laminated in this order. It was done.

The polypropylene resin used for the polypropylene resin sheet includes propylene homopolymer, ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-propylene-butene random terpolymer, propylene-vinyl chloride copolymer, propylene- Resins having a propylene content of 50% by weight or more, such as butene copolymers and propylene-maleic anhydride copolymers, may be used alone or in admixture of two or more. The polypropylene-based resin is preferably in a non-crosslinked state, but may be crosslinked with peroxide or radiation.

As the polypropylene resin,
You may use what mixed the other thermoplastic resin which can be mixed with this polypropylene resin. Specific examples of such other thermoplastic resins include, for example, low density polyethylene,
Examples thereof include polystyrene, polybutene, and ionomers, and the amount of these thermoplastic resins compounded is usually 20 parts with respect to 100 parts of the polypropylene resin (parts by weight, the same applies hereinafter).
It is preferable that the amount is not more than 5 parts, especially about 5 to 10 parts.

The thickness of the polypropylene-based resin sheet is not particularly limited, but if it is too small, the feeling of weight becomes poor, and if it is too large, the flexibility becomes poor. Therefore, it is usually 0.3 to 2 mm, preferably 0.5 to 1.5 mm.

The polyolefin resin in-mold foam sheet having a high expansion ratio can be obtained by in-mold foam molding of polyolefin resin pre-expanded particles.

Specific examples of the polyolefin resin include polypropylene, polyethylene and ethylene.
Examples thereof include propylene copolymer, chlorinated polypropylene, chlorinated polyethylene, ethylene-propylene-butene terpolymer, and mixtures thereof, but the present invention is not limited to these examples. Among these resins, polypropylene, polypropylene such as polypropylene, ethylene-propylene copolymer, etc. are considered in consideration of recyclability, heat resistance, and adhesiveness with a polypropylene resin sheet or a polypropylene resin in-mold foam having a low expansion ratio. Resins are particularly preferable.

If the expansion ratio of the polyolefin resin in-mold foam sheet having the high expansion ratio is too large, the obtained automobile interior material will be too soft to the touch, and will also be too small. If too much, the obtained automobile interior material tends to be too hard to feel, so it is usually 20 to 50 times, preferably 25 to 45 times, more preferably 30 to 40 times. desirable.

If the thickness of the polyolefin-based resin foamed sheet is too small, the cushioning property of the polyolefin-based resin foamed sheet tends to be small, and if it is too large. Is preferable to be 0.5 to 5 mm, especially 1 to 3 mm, since the obtained automobile interior material tends to be too soft to the touch.

The polypropylene-based resin sheet and the polyolefin-based resin in-mold foam sheet having a high expansion ratio can be integrated by, for example, a method of heating and melting to integrate, or a method of integrating both with an adhesive. It can be carried out and the invention is not limited by such an integration method.

In the present invention, the polypropylene-based resin sheet and the polyolefin-based resin in-mold foam sheet having a high expansion ratio are previously prepared as an integrated body, and the polypropylene resin having a low expansion ratio is prepared. It may be integrated with the in-mold resin foam.

The polypropylene resin in-mold foam having a low expansion ratio can be obtained by in-mold foam molding of polypropylene resin pre-expanded particles.

When the polypropylene resin pre-expanded particles are filled in the molding die through the feeder, the pre-expanded particles are preliminarily pressurized with a pressurized gas so that the pressurized gas is sufficiently contained in the pre-expanded particles. The pre-expanded particles may be filled into the mold while being infiltrated and given an internal pressure, or the pre-expanded particles may be packed into the mold by compression while being compressed with a pressurized gas. The particles may be filled in the molding die as they are without applying an internal pressure or compression, and the present invention is not limited to such a filling method.

If the expansion ratio of the polypropylene-based resin in-mold foam is too large, mechanical properties such as compressive strength and bending strength of the obtained automobile interior material will be inferior, and will be too large. If it is too small, the feel of the obtained automobile interior material tends to be too hard, so it is usually 5 to 25 times, preferably 7 times.
It is desirable to be 20 times.

In order to sufficiently provide the obtained automobile interior material with a two-step cushioning property, the expansion ratio of the polyolefin-based resin in-mold foam sheet and the polypropylene-based resin in-mold foam ratio. It is desirable that the difference is 5 times or more, preferably 10 times or more.

If the thickness of the polypropylene resin in-mold foam having a low expansion ratio is too small, the obtained automobile interior material may have poor mechanical properties such as compressive strength and bending strength. If it is too large, there is a tendency for problems to occur in the design of the obtained automobile interior material.
mm, preferably 5 to 30 mm, more preferably 5 to 20 mm.

The polyolefin resin in-mold foam sheet having a high expansion ratio and the polypropylene resin in-mold foam are integrated by, for example, heating and melting the contact surfaces of the in-mold foam sheet and the in-mold foam respectively. After that, it can be carried out by a method of superimposing and fusing and integrating, and a method of integrating the in-mold foam sheet with the in-mold foam by an adhesive agent. In the present invention, a polypropylene resin sheet is further added. And a polyolefin-based resin in-mold foam sheet are prepared in advance, and this is mounted in an in-mold foam molding die, and then filled with polypropylene resin pre-expanded particles to form an in-mold foam molded article. at the same time,
A method of integrating the laminate with the in-mold foam molding can be adopted.

Thus, the automobile interior material of the present invention is obtained. In the present invention, a laminate of the polypropylene resin sheet and the polyolefin resin in-mold foam sheet is formed into a desired shape by, for example, a vacuum forming method. It may be mounted in a mold for in-mold foam molding, and then filled with pre-expanded particles to be in-mold foam-molded and integrated to obtain an automobile interior material having a desired shape. The in-mold foamed article may be laminated with the above-mentioned laminate softened by heating to be integrated to obtain an automobile interior material having a desired shape.

Next, FIG. 1 shows a schematic cross-sectional view of an automobile interior material of the present invention.

In FIG. 1, 1 is a polypropylene resin sheet, 2 is a polyolefin resin in-mold foam sheet, 3
Is a polypropylene resin in-mold foam. A polyolefin resin in-mold foam sheet 2 is formed on the lower surface of the polypropylene resin sheet 1, and a polypropylene resin in-mold foam body 3 is formed on the lower surface of the in-mold foam sheet 2. Since the polypropylene-based resin in-mold foam body 3 does not directly appear as an outer skin to the outside, a meat steal 5 may be formed in the inside for the purpose of reducing the weight, and for connecting with other members. An insert material 4 such as a fixture may be provided. The insert material 4 such as the fixture can be integrated with the in-mold foam when manufacturing the in-mold foam.

The shape of the insert material 4 may be adjusted according to the shape of the fixture or the like. Examples of the material of the insert material 4 include metal, polyethylene,
Examples of the resin include thermoplastic resins such as polypropylene and ABS resin, thermosetting resins such as phenol resin and formaldehyde resin, but the present invention is not limited to these examples. The surface of the insert material 4 may be preliminarily attached with, for example, the above-mentioned adhesive or the like in order to improve the adhesiveness with the pre-expanded particles.

Next, the automobile interior material of the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

EXAMPLE 1 A polypropylene resin sheet (thickness 0.75 mm) and a polypropylene resin in-mold foam sheet having a high expansion ratio (expansion ratio 30 times, thickness 3 mm) are integrated by heating and melting. The product was attached so that the resin sheet was in contact with a flat plate-shaped mold surface having no steam holes.

Further, a die having a steam hole (vertical 300 mm,
An iron hook (surface coating: ethylene-vinyl acetate resin) for fixing the set screw was fixed as an insert material to a part of the inner surface of the width 800 mm, depth 20 mm).

Eperan PP (trade name, manufactured by Kanegafuchi Chemical Industry Co., Ltd.) was used as pre-expanded polypropylene resin particles to give a polypropylene resin in-mold foam having a low expansion ratio.
Put a foaming ratio of 15 times) in a pressure resistant container in advance and set the internal pressure to 2
Using a mold in which kg / cm ² · G was given by air, the mold was filled with the mold.

Next, steam (steam pressure 0.6 kg / cm ² · G, temperature 113 to 114 ° C.) was introduced into the mold from a mold having steam holes and preheated, and the pre-expanded particles were prepared for about 10 seconds. After steaming, the drain and water vapor were removed by suction using a vacuum pump so that the internal pressure in the mold was 500 mmHg or less.

After that, steam (vapor pressure: 3.5 kg / cm ² · G, temperature: 146 to 148 ° C.) was introduced into the mold from a mold having steam holes, and the mold was held for 25 seconds and then cooled to form the mold. The mold was opened to obtain an automobile interior material.

As the physical properties of the obtained automobile interior material, the feeling, cushioning property, odor at high temperature, recyclability and generation of harmful gas during combustion were examined according to the following methods. The results are shown in Table 1.

(A) Feel As a conventional automobile interior material, a polyvinyl chloride sheet (thickness 0.5 mm), a polypropylene resin in-mold foam sheet (foaming ratio 20 times, thickness 3 mm) and ABS resin plate (thickness) 2 to 3 mm) were sequentially laminated to obtain a product (hereinafter referred to as conventional product A).

Next, the tactile sensation of the obtained automobile interior material was examined by pressing it with a finger, and compared with the conventional product A, evaluation was made based on the following evaluation criteria.

(Evaluation Criteria) A: The obtained automobile interior material is obviously softer and more supple than the conventional product A. B: The obtained automobile interior material is slightly softer and more supple than the conventional product A. C: There is almost no difference in touch between the obtained automobile interior material and the conventional product A. D: The conventional product A has a better tactile feel than the obtained automobile interior material.

(B) Buffering property A steel ball weighing 100 g was dropped from a position of 50 cm in height on the surface portion of the obtained automobile interior material and conventional product A on the skin side, and based on the following evaluation criteria. And evaluated.

(Evaluation Criteria) A: The height of the steel ball when the steel ball is dropped and rebounded is higher in the conventional product A. B: The height of the steel ball when dropped and rebounded is almost the same in both the conventional product A and the obtained automobile interior material. C: The height of the steel ball when the steel ball was dropped and rebounded was higher in the interior material for automobiles.

(C) The interior materials for automobiles and the test pieces (20 × 20 cm) of the conventional product A, which had an odor at high temperature, were separately heated at a temperature of 60 ° C. and a relative humidity of 50.
After being left for 24 hours in a constant temperature and humidity chamber, the evaluation was performed based on the following evaluation criteria.

(Evaluation Criteria) A: When the door of the constant temperature and constant humidity chamber is opened, no odor is felt by the obtained automobile interior material. B: When the door of the constant temperature and humidity chamber is opened, an odor due to the obtained automobile interior material is felt, but it is weaker than the conventional product A. C: When the door of the constant temperature and constant humidity chamber was opened, the odor caused by the obtained automobile interior material was almost the same as that of the conventional product. D: When the door of the constant temperature and constant humidity chamber was opened, the odor caused by the obtained automobile interior material was stronger than that of the conventional product A.

(D) Recyclability The recyclability of the obtained automobile interior material was evaluated based on the following evaluation criteria.

(Evaluation Criteria) A: The obtained automobile interior material can be directly used for recycling without having to disassemble the constituent materials. B: If the obtained interior materials for automobiles are decomposed into each constituent material, any of them can be used for recycling. C: The obtained automobile interior materials include materials that cannot be recycled.

(E) Generation of harmful gas It is examined whether or not the constituent materials of the obtained automobile interior material include a material which is generally said to generate a harmful gas at the time of combustion, and evaluated based on the following evaluation criteria. Was done.

(Evaluation Criteria) A: Materials that are generally said to generate harmful gas during combustion are not included. B: Some materials that are said to generate toxic gas during combustion are included. C: All materials are generally said to generate harmful gas upon combustion.

Example 2 Instead of the laminate used in Example 1, a polypropylene resin sheet (thickness 0.5 mm) and a polypropylene resin in-mold foam sheet having a high expansion ratio (expansion ratio 45 times, thickness)
2.5 mm), and the resin sheet surface of the laminated sheet was attached to the inner surface of the flat mold, and no insert material was used. I got it.

The physical properties of the obtained automobile interior material are shown in Example 1.
I examined it in the same way. The results are shown in Table 1.

Example 3 A polypropylene resin sheet (having a thickness of 0.75) was used as a skin material.
mm) and a polypropylene-based resin in-mold foam sheet having a high expansion ratio (expansion ratio 40 times, thickness 3.5 mm), and the resin sheet surface of the laminated sheet was attached to a flat mold. .

Further, a die having a steam hole (vertical 300 mm,
A polyolefin resin hook (surface coating: chlorinated polypropylene) for fixing the set screw was fixed as an insert material to a part of the inner surface of the horizontal 800 mm, depth 20 mm).

Eperan PP (trade name, manufactured by Kanegafuchi Chemical Industry Co., Ltd.) was used as pre-expanded polypropylene resin particles to give a polypropylene resin in-mold foam having a low expansion ratio.
A foaming ratio of 15) was filled in the molding die through the feeder.

Next, steam (vapor pressure of 0.
5 kg / cm ² · G, temperature 109-113 ℃) was introduced into the mold to preheat, depressurize and steam the pre-expanded particles for 10 seconds, and then the internal pressure in the mold was 400 mmHg or less. The drain and water vapor were removed by suction using a vacuum pump.

After that, steam (vapor pressure: 3.2 kg / cm ² · G, temperature: 144 to 146 ° C.) was introduced into the mold through the steam holes of the mold, and the mold was held for 20 seconds and then cooled. The mold was opened to obtain an automobile interior material.

The physical properties of the obtained automobile interior material are shown in Example 1.
I examined it in the same way. The results are shown in Table 1.

Example 4 In Example 3, as the polypropylene resin pre-expanded particles, Eperan PP (trade name, manufactured by Kanegafuchi Chemical Industry Co., Ltd.) was used.
The process from filling the pre-expanded particles to suction removal of the drain and water vapor was performed in the same manner as in Example 3 except that the expansion ratio was 15 times) and the insert material was not used.

Next, steam (vapor pressure 3.
5 kg / cm ² · G and a temperature of 146 to 148 ° C.) were introduced into the mold, held for 20 seconds, cooled, and then the mold was opened to obtain an interior material for automobile.

The physical properties of the obtained automobile interior material are shown in Example 1.
I examined it in the same way. The results are shown in Table 1.

Comparative Example 1 As a conventional automobile interior material, a leather sheet made of polyvinyl chloride (thickness 0.5 mm), a foamed polyurethane layer (thickness 10 mm) and an ABS resin plate (thickness 2 mm) are sequentially laminated, The integrated product was obtained as a laminate (hereinafter referred to as conventional product B).

The physical properties of the obtained conventional product B were examined in the same manner as in Example 1. The results are shown in Table 1.

[0065]

[Table 1]

From the results shown in Table 1, the automobile interior materials of the present invention obtained in Examples 1 to 4 could not have all of the conventional products A and B, and had an excellent feeling. It can be seen that, at the same time, it has excellent buffering properties, odorless at high temperature, excellent recyclability, and no generation of harmful gas during combustion.

The interior materials for automobiles of the present invention obtained in Examples 1 to 4 all had a feeling of weight, but since they are lighter than the conventional product B, they constitute automobiles. It was able to fully meet the demand for weight reduction of existing parts.

[0068]

Industrial Applicability The automobile interior material of the present invention provides a soft and supple feel when pressed, has excellent cushioning properties, has a heavy feeling, does not generate a bad odor at high temperatures, and emits noxious gas when burned. It produces a number of excellent effects, such as a small amount of waste generated, weight reduction, and easy recycling.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an example of an automobile interior material of the present invention.

[Explanation of symbols]

 1 Polypropylene-based resin sheet 2 Polyolefin-based resin in-mold foam sheet 3 Polypropylene-based resin in-mold foam

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Claims (5)

[Claims] 1. An automobile interior material comprising a polypropylene resin sheet, a polyolefin resin in-mold foam sheet having a high expansion ratio, and a polypropylene resin in-mold foam having a low expansion ratio, which are sequentially laminated. 2. The interior material for automobiles according to claim 1, wherein the foaming ratio of the polyolefin resin in-mold foam sheet is 20 to 50 times. 3. The interior material for automobiles according to claim 1, wherein the foaming ratio of the polypropylene resin in-mold foam is 5 to 25 times. 4. The automobile interior material according to claim 1, 2 or 3, wherein the difference between the expansion ratio of the polyolefin resin in-mold foam sheet and the expansion ratio of the polypropylene resin in-mold foam is 5 times or more. 5. The method according to claim 1, 2, 3 having an insert material.
Alternatively, the automobile interior material described in 4 above.