JP3532767B2 - Instrument panel manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing an instrument panel. In particular, the present invention relates to a method of reusing an already used instrument panel to produce an instrument panel having sufficient physical properties as a panel.

[0002]

2. Description of the Related Art Instrument panels for automobiles are
It is a part that incorporates various meters and switches and is attached to the front of the vehicle. Generally, as this panel, in order to alleviate the impact on the human body at the time of a collision accident and to improve the design as a panel, a skin material formed of a soft resin material is formed on the surface of the impact resistant resin molded product. The glued type is often used.

According to Japanese Examined Patent Publication No. 7-8628, a panel referred to as a skin-incorporated instrument panel is formed on a base material core made of an olefin resin molded body.
It is introduced as a panel in which a laminated sheet in which an olefin elastomer skin is attached to an olefin resin foam pad is integrated with an olefin adhesive. It is described that with such a structure, the surface has a sufficient soft feeling, can be manufactured at low cost, and the waste material can be reused by adopting a similar material.

However, at the present time when there is a strong demand for recycle use, when the used instrument panel with the skin still on it is reused to restore the original product, the machine required for the base material core is required. Since it has deteriorated from the physical properties, it cannot be reused as it is.

Further, if the base material core is reused after the pad with the skin material is separated in advance, the mechanical properties are close to the initial physical properties, but it is still insufficient for use as a product. In addition, the separation operation becomes a factor of cost increase, and it becomes necessary to separately treat the collected pad with the skin material, which is not a rational recycling method.

[0006]

Therefore, the present inventors
Intended to be used again the used instrument panel remains with a skin material, also rigidly, impact resistance, for the manufacture of a panel with balanced physical properties such as heat resistance, intensive studies As a result, the present invention has been reached.

[0007]

Means for Solving the Problems] Specifically, the present invention, the surface of the polypropylene substrate, use of the instrument panel and the pad constructed from a polypropylene foam and olefinic elastomeric skin, which are bonded and integrated Already
A step of crushing a sample to obtain a composition consisting of 70 to 92% by weight of an olefin resin and 8 to 30% by weight of an inorganic filler, to which a propylene block copolymer, an ethylene copolymer rubber, and an inorganic material are newly added. A step of obtaining a resin composition adjusted to have a polypropylene content of 45 to 65% by weight, an ethylene copolymer rubber content of 10 to 20% by weight, and an inorganic filler content of 25 to 35 % by weight by adding a filler and melt-kneading. And a step of molding a panel base material from the composition, the method for producing an instrument panel.

In particular, the panel base material produced from the resin composition has a flexural modulus of 2600 MPa or more, an Izod impact strength of 200 J / m or more, and a heating deformation temperature (load of 4).
It preferably has a physical property of 55 KPa) 130 ° C. or higher.

[0009] instrument panel for use in the present invention, the pad and the skin on the substrate surface has a bonded structure in this order, the panel is one that is used is attached to the actual car after molding . Since this panel is used as a part of the base material in the present invention, an instrument panel made of a polyolefin-based material whose base material, pad and skin are as similar as possible is adopted.

The base material of the panel is material-designed so as to retain the shape of the panel and have mechanical strength and heat resistance to withstand impact, and in consideration of reuse, polypropylene is desirable. In particular, when this polypropylene is a composition obtained by adding an ethylene copolymer rubber to a propylene homopolymer or a block copolymer produced from propylene and ethylene, it is advantageous because it imparts excellent impact resistance to the panel. Is. Further, for the purpose of imparting rigidity to the panel, it is desirable that an inorganic filler such as talc is blended in an amount of 10 to 30% by weight.

The pad is made of foam in order to absorb the impact from the surface side and to improve the tactile sensation. The foam suitable for reuse is mainly polypropylene, especially propylene homopolymer or copolymer. It is what A skin is adhered to one surface of the pad, but if the skin is made of an olefinic thermoplastic elastomer sheet, it has good compatibility with other resins, which is convenient for reuse.

The once-formed instrument panel having such a structure is subjected to mechanical crushing treatment when reused to obtain a powdery or granular crushed product. The olefin polymer component in the crushed material is 70 to 92, preferably 76 to 88% by weight, and the inorganic filler is 8 to 30, preferably 12 to 24% by weight. When the olefin polymer and the inorganic filler are within this composition range, they are suitable for recycling use according to the present invention.
The term "olefin-based polymer" is used herein as a generic term for the olefin-based polymer material mainly composed of polypropylene derived from the base material, the pad, and the skin, and may be mixed in the crushed material. Other olefin polymers such as polyethylene, copolymer rubber of ethylene and propylene, and olefin elastomer are also used in the meaning.

The additional materials newly added to the crushed product are propylene block copolymer, ethylene copolymer rubber and inorganic filler, which are added to the base material depending on the content and composition of the crushed product. Depending on the required physical properties, the material composition to be added is appropriately adjusted as described below.

Ethylene copolymer rubbers include ethylene / propylene copolymers, ethylene / butene-1 copolymers, ethylene / hexene-1 copolymers, ethylene / octene-polymers.
An ethylene / α-olefin copolymer having rubber-like properties such as a 1-copolymer having a density of 0.85 to 0.9.
A value of 0, preferably 0.86 to 0.89 g / cm ³ , is suitable, and the impact resistance of the base material is improved by blending the ethylene copolymer rubber.

Examples of the inorganic filler to be further blended include talc, glass fiber, calcium carbonate and the like, but it is preferable to employ the same type of inorganic material as the inorganic filler contained in the crushed material. Among these, the particle size is 0.1-5μ
The use of m of talc is highly effective in increasing the rigidity of the base material.

[0016] As the polypropylene to be added blended propylene block copolymer having excellent impact resistance even in the polypropylene is used. The block copolymer referred to here is a composition in which a copolymer of polypropylene and propylene and ethylene is mainly mixed uniformly, and both polymers are produced by a production means such as a multistage polymerization method, It may be made directly by chemical blending during the manufacturing process, or each polymer may be made separately beforehand and then
It may then be manufactured by mechanical blending.

The crushed product of the instrument pannel once molded, and the newly added polypropylene, ethylene copolymer rubber, and inorganic filler are melt-kneaded to form a uniform mixture. During this melt-kneading, a heat resistance stabilizer, an antioxidant, a weather resistance stabilizer, an antistatic agent, a flame retardant, a lubricant, a nucleating agent, a slip agent, a pigment, etc. should be added within a range that does not impair the object of the present invention. Can be done. The melt-kneading can be performed using an extruder, a kneader, a Brabender, etc., and in particular, kneading is performed using a single-screw extruder or a twin-screw extruder with a cylinder temperature set to 170 to 250 ° C., and recovered as pellets. The method of doing is convenient.

The pellet composition after melt-kneading is polypropylene 45 to 65, preferably 50 to 60% by weight, ethylene copolymer rubber 10 to 20, preferably 12 to 18.
It is preferable that the content of the inorganic filler is adjusted to the range of 25 to 35% by weight in order to satisfy the physical properties of the base material. The ethylene copolymer rubber also contains an olefin elastomer component derived from the skin.

A base material is manufactured from the above-mentioned resin composition by a molding means such as injection molding or blow molding according to the shape of the base material. The base material is responsible for the main physical properties of the instrument panel. Therefore, it must have sufficient mechanical strength and heat resistance by itself. In particular, the panel substrate manufactured from the resin composition,
Flexural modulus 2600 MPa or more, Izod impact strength 2
00 J / m or more, and heat distortion temperature (load 455 KP
a) It preferably has physical properties of 130 ° C. or higher. In addition, it has been used so that it exhibits these physical properties .
Utilization of the instrument panel pulverized product, i.e. by adjusting the recycle ratio, also newly added propylene Bro
Copolymer, ethylene copolymer rubber, inorganic filler
It is preferable to adjust the blending amount of the above, and control so that the above resin composition is obtained as a result. The thickness of the substrate is usually 2.
It is molded to 5 to 4.0 mm.

[0020] The surface layer in a variety of ways to molded substrate is formed, usually have a skin formed of the pad and an olefin-based thermoplastic elastomer formed of a polyolefin foam is laminated, the product shape . In this integration step, the two-layer sheet is overlaid on the base material, and by degassing from the base material side or the skin side, the desired shape can be easily formed by the vacuum forming method. An instrument panel can be manufactured.

Since the pad mainly absorbs a shock from the surface side, a closed cell body having a cell strength sufficient to absorb the shock is preferable, and usually has a thickness of 1.0 to 4.0 mm.
Polypropylene foam is used. The epidermis is 0.
Although it is manufactured to a thickness of about 3 to 0.8 mm, it is a part that mainly protects the surface of the panel and exhibits the design of the panel, and many materials are made by blending polypropylene with an olefin-based thermoplastic elastomer. It is used by applying a texture pattern on the surface of the sheet.

Since both the pad material and the skin material are olefinic materials and easily heat-sealed, they can be easily joined by heat-welding without using a special adhesive. Therefore, by using a laminated sheet in which both materials are bonded in advance, it is possible to simplify the integration with the base material, the pad, and the skin in the above vacuum forming step. Further, in the vacuum forming process, if applied olefinic or urethane-based adhesive to the substrate or pad side, is bonded and integrated to the molded simultaneously with three layers ends.

[0023]

The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples.

Comparative Example 1 Melt flow rate (AST
MD-1238; 230 ° C, 2.16 kg) was 15.
2 g / 10 minutes, 71% by weight of propylene / ethylene block copolymer having an ethylene content of 14.5 mol%, 9% by weight of ethylene / octene-1 copolymer rubber, and 20% by weight of talc having an average particle size of 3 μm. A test piece was prepared by injection molding.
The results of measuring the physical properties are shown in Table 1.

(Comparative Example 2) From the resin composition used in Comparative Example 1, a substrate of an instrument panel is molded by injection molding, and a polypropylene foam is further formed on the surface of the substrate and an olefin-based elastomer skin is formed. An instrument panel was previously manufactured by adhering the laminated sheet obtained by bonding the above. The thickness composition of the panel is as follows: base material: pad: skin = 4.0: 2.5: 0.65 (unit: m
m). This panel was heat-treated at 110 ° C. for 500 hours and then pulverized by a pulverizer to obtain a resin temperature of
Pelletized using a single screw extruder set at 0 ° C.
Test pieces were prepared from these pellets by injection molding, and the physical property measurement results are shown in Table 1.

Example 1 The crushed material obtained in Comparative Example 2 was used, and the propylene / ethylene block copolymer, ethylene / octene-1 copolymer rubber, and talc used in Comparative Example 1 were newly added. The compounding amounts shown in Table 1 were added and melt-kneaded at 200 ° C. using a twin-screw extruder to obtain pellets. Test pieces were prepared from these pellets by injection molding, and the physical property measurement results are shown in Table 1.

(Comparative Examples 3 to 4) Using the crushed material obtained in Comparative Example 2, polypropylene and talc were added to the compounding amounts shown in Table 1 and melt-kneaded using a twin-screw extruder. And pellets were obtained. Test pieces were prepared from these pellets by injection molding, and the physical property measurement results are shown in Table 1.

The physical properties were measured according to the measuring methods described below. 1) Melt flow rate: ASTM D1238; 23
0 ° C., 2.16 kg (unit: g / 10 min) 2) Tensile yield strength: ASTM D638; tensile speed 30 mm / min) (unit MPa) 3) Bending strength: ASTM D790; bending speed 30 mm / min) (unit MPa) ) 4) Flexural modulus: ASTM D790; Bending speed 30 mm / min) (Unit: MPa) 5) Izod impact strength: ASTM D256; Notched, 23 ° C (Unit: J / m) 6) Heat distortion temperature: ASTM D648; A Law:
Load 455KPa B method: Load 1820KPa (unit: ° C) 7) Specific gravity: ASTM D792

From the results of the comparative example in Table 1, once molded,
When the instrument panel heat-treated at 110 ° C. for 500 hours is simply crushed and the pelletized material is used again, the rigidity and heat resistance are low, and the physical properties of the instrument panel base material are insufficient as they are. However, as can be seen from the results of the examples, it has been found that an instrument panel base material having a sufficient physical property balance can be manufactured by adding a new material to have a specific composition.

[0030]

[Table 1] * Ethylene copolymer rubber (including skin elastomer component)

[0031]

According to the method of manufacturing an instrument panel according to the present invention, a used panel is crushed and a new material is added to obtain a specific composition range. Therefore, sufficient mechanical strength and heat resistance can be obtained. In addition, it is possible to easily manufacture a new panel having a good balance of impact resistance, rigidity and heat resistance.

Improvements were also seen in tensile elongation, DuPont impact strength, Rockwell hardness, gloss, and molding shrinkage. In the present invention, in particular, since a large amount of used panels can be reused, it is possible to increase the recycling rate and contribute to the reuse of resources.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C08L 23/10 C08L 23/10 (72) Inventor Keiichi Honjo 1-4-1 Chuo 1-chome, Wako City, Saitama Prefecture (72) Inventor Keigo Suehiro 3 in Chikusaigan, Ichihara-shi, Chiba Within Grand Polymer Co., Ltd. (56) References JP-A-10-1573 (JP, A) JP-A-10-36586 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08J 5/00-5/24 C08J 11/00-11/28 B29C 71/00-73/34 B60K 37/00-37/06 C08L 1/00- 101/14

Claims (2)

(57) [Claims] 1. A used product of an instrument panel in which a pad made of a polypropylene foam and an olefin elastomer skin are bonded and integrated on the surface of a polypropylene base material, and a used product is crushed. 70-92% by weight of coalescence and 8-30% by weight of inorganic filler
Obtaining a composition comprising a newly propylene thereto
A block copolymer, an ethylene copolymer rubber, and an inorganic filler are added and melt-kneaded to provide polypropylene 45 to 65% by weight, an ethylene copolymer rubber 10 to 20% by weight, and an inorganic filler 25 to 35. A method for producing an instrument panel, comprising: a step of obtaining a resin composition adjusted to have a weight percentage; and a step of molding a panel base material from the composition. 2. The panel base material has a flexural modulus of 2600 M.
The method for manufacturing an instrument panel according to claim 1, wherein the method has the physical properties of Pa or higher, Izod impact strength of 200 J / m or higher, and heat distortion temperature (load 455 KPa) of 130 ° C. or higher.