JPH0520608Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to the improvement of ceiling materials for automobiles, and meets high requirements such as deep and sharp formation, good heat resistance, and light weight. This was done in order to obtain an inexpensive automobile ceiling that could meet these demands.

(Conventional technology) Automotive ceilings include pasted ceilings, suspended ceilings,
Although there are molded ceilings, molded ceilings are currently the mainstream because they have advantages such as creating a three-dimensional effect, providing a large head clearance, and being easy to assemble.

The qualities (required qualities) required for molded ceilings include rigidity, heat resistance, moldability, handling properties, heat insulation properties, and also beauty and softness as interior materials. Conventionally, as a base material,
Relatively hard materials such as resin felt, bubble honeycomb, and cardboard are used, and
As surface materials, pad materials such as polyurethane foam and polyethylene foam, and skins such as knitwear and vinyl chloride leather, have been used to provide a soft feel. For this type of molded ceiling, for example, non-foamed propylene polymer sheet/polypropylene foam/non-foamed propylene polymer sheet is used as the base material, and polyurethane foam/cloth, PVC leather, etc. It was used as a surface material, and a five-layer laminate was devised by laminating these materials (in 1987).
-Refer to Publication No. 148926).

In addition, we have developed a 5-layer structure in which polypropylene sheets are laminated on both sides of a cross-linked polypropylene foam layer, and a surface material consisting of a soft surface decorative material layer is laminated via a polyurethane foam layer. (See Japanese Patent No. 140151/1983) has been disclosed.

Furthermore, copolymers of ethylene and propylene,
A plate-shaped foam laminate (see Japanese Utility Model Laid-Open Publication No. 59-56027) has been disclosed in which a polyolefin thermoplastic resin film is laminated to a main material formed by arranging and bundling foamed strips of a polyolefin resin made of a mixed resin of a thermoplastic resin such as polypropylene resin and polyethylene, or other olefin-based copolymer.

(Problem to be solved by the invention) However, in the molded ceilings disclosed in the above-mentioned Utility Model Application Publication No. 55-148926 and Japanese Patent Application Publication No. 57-140151, several layers are laminated to form a foam. The structure is complicated and the manufacturing process is complicated because the surface is decorated by laminating a surface material on top of the surface. Additionally, the multi-layered structure makes it thicker, which inevitably narrows the space inside the car. Furthermore, since polyurethane foam is heavy and cannot be molded, it has the disadvantage that it is not possible to obtain a beautiful sculptural appearance through deep, sharp molding.

In addition, in the case of the plate-shaped foam laminate disclosed in the above-mentioned Japanese Utility Model Publication No. 59-56027, in order to fuse the strips, it is necessary to construct the main material with a non-crosslinked foam material that melts easily. Heat resistance cannot be obtained. As a result, when molded as a ceiling material for an automobile, a deep and sharp shape cannot be obtained during molding, and the finished ceiling material also sags due to heat, resulting in inconveniences.

The present invention was developed in view of the above circumstances, and aims to provide a ceiling material for automobiles that can be formed deeply and sharply, has excellent heat resistance, and is lightweight and inexpensive.

(Means for solving the problem) The automobile ceiling material of the present invention is made of a random copolymer of ethylene and propylene, a block copolymer,
Or one or more propylene copolymers selected from random block copolymers10
A non-foamed skin layer made of a propylene polymer is laminated on both sides of a crosslinked highly foamed sheet made of ~80% by weight and linear low density polyethylene of 90% to 20% by weight, and at least One side has an uneven pattern such as a grain pattern.

(Function) The automobile ceiling material of the present invention is composed of three layers: a non-foamed skin layer made of a propylene polymer is laminated on both sides of a cross-linked highly foamed sheet. At this time, the crosslinked highly foamed sheet is made of one or more propylene copolymers selected from random copolymers, block copolymers, or random block copolymers of ethylene and propylene, and a linear low-foam sheet. It consists of density polyethylene, and the propylene copolymer accounts for 10 to 80% by weight.
The presence of ethylene in the propylene-based copolymer lowers the melting point of the copolymer and improves its thermal adhesion with the skin layer. At the same time, since the proportion of linear low-density polyethylene is 90 to 20% by weight, the strength and
It has good heat resistance, provides sufficient flexibility as a foam, and retains the original processability of polyethylene. In particular, since linear low-density polyethylene having a linear molecular structure is used compared to ordinary low-density polyethylene, the stress cracking resistance is significantly improved. Further, the above-mentioned formulation improves the fact that the crosslinked homopolypropylene foam sheet becomes too hard. In other words, the cross-linked highly foamed sheet maintains a good balance of appropriate rigidity and flexibility, and is also suitable as a foam for automobile ceiling materials in terms of moldability, heat resistance, etc. obtained in a single layer.

Further, in conjunction with the properties of such a crosslinked highly foamed sheet, an uneven pattern such as a grain pattern can be directly applied to at least one of the skin layers, so an extra decorative skin layer is not required.

(Example) Hereinafter, embodiments of the present invention will be described with reference to the drawings. In Figures 1 and 2, 1a,
1b is a non-foamed surface layer made of a propylene polymer, 2a and 2b are crosslinked highly foamed sheets made of ethylene, propylene copolymer, and linear low density polyethylene, and 3a and 3b are non-foamed surface layers made of a propylene polymer. It is a foamed skin layer, and the surface of the skin layer 3a has an uneven pattern, for example, a grain pattern 5.

The above surface layer preferably has a thickness of 0.06 mm to 0.6 mm,
More preferably, it is 0.09 mm to 0.4 mm. In addition,
Examples of the propylene-based polymer include block copolymers and random copolymers of polypropylene and monomers copolymerizable with propylene such as ethylene, and blend resins thereof may also be used. In addition, inorganic or organic substances such as pigments, heat retardants, antistatic agents, and extenders can also be added as necessary.

The crosslinked highly foamed sheets 2a and 2b are formed from a copolymer of ethylene and propylene and linear low density polyethylene.

As the above ethylene/propylene copolymer,
Examples include random copolymers, block copolymers, and random block copolymers of ethylene and propylene. However, this ethylene-propylene copolymer has a melting point of 130~
Preferably it is done between 170°C. In addition, the melt flow rate (MFR) is preferably 0.1 to 50,
More preferably it is 0.3-30.

In addition, the MFR of the above linear low density polyethylene is
It is preferably 0.1-50, more preferably 0.2-30.

In addition, when the amount of ethylene-propylene copolymer in a foam sheet increases, it becomes heat resistant and strong, but on the other hand, it breaks easily and has low impact strength, especially at low temperatures.
Too hard and poor cushioning properties. Furthermore, thermoforming using an extruder or the like becomes difficult, and the crosslinking agent and foaming agent decompose, making it impossible to obtain a good molded product or a good foam. Conversely, when the amount of ethylene-propylene copolymer decreases and the amount of linear low-density polyethylene increases, physical properties such as heat resistance and mechanical strength decrease. Therefore, ethylene in the foam sheet
The amount of the propylene copolymer is preferably 10 to 80% by weight, more preferably 20 to 70% by weight.

The foam sheet is a highly foamed material, and the expansion ratio is preferably 10 to 50 times, more preferably 20 to 40 times.

In the present invention, the crosslinked highly foamed sheets 2a, 2
On both sides of b, non-foamed skin layers 1a, 3a, 1b,
3b is laminated, but the lamination methods include attaching the sheets to each other using heat or adhesive, and directly attaching them to the foam sheet when molding the sheet by melt extruding the resin. Examples include the so-called extrusion lamination method.

Also, on the surface of the epidermis layer, as shown in Figure 2,
The soft film 4b may be laminated, and in this case, an uneven pattern such as a wrinkled pattern is formed on the surface of the soft film 4b. For the soft film 4b
A soft film such as EPR, TPE, PE, or EVA, a blend film thereof, or a soft PVC film is preferable.

In addition, if a soft feel is required for the surface with the grain pattern 5 on the interior side of the vehicle, the non-foamed skin layer 3a made of a propylene-based polymer may be coated with ethylene propylene rubber, for example, within the range that does not impair the rigidity. (EPR), thermoplastic elastomer (TPE), polyethylene (PE), ethylene-
Add vinyl acetate copolymer (EVA) etc.
As shown in Figure 2, on the surface of the three-layer structure laminate,
It is preferable to affix a thin flexible film 4b such as an individual or blended film such as EPR, TPE, PE, or EVA, or a soft PVC film, and of course, a textile product such as knit or nonwoven fabric may also be affixed. Further, it is preferable that the epidermal layer facing the indoor side is colored with a pigment in a desired color.

The grain pattern 5 can be applied by using a grain roll when forming the sheet or film, by using a grain roll or grain mold when heat-sealing the sheet or film, and by applying heat to give the shape. There is a method of attaching it by using a mold with grains during the molding process.

(Example 1) In FIG. 1, the non-foamed skin layer 1a is
It is a sheet with a thickness of 0.3 mm obtained by extrusion of polypropylene homopolymer with an MFR of 0.9, a melting point of 172°C, and a density of 0.9. A closed-cell, cross-linked, highly foamed sheet made of 30% by weight of α-olefin propylene copolymer at 142°C and 40% by weight of linear low-density polyethylene with a melting point of 120°C, with an expansion ratio of 30 times and a thickness of 4 mm. be. The non-foamed surface layer 3a is a 0.3 mm sheet made of the same polypropylene polymer and pigment as the skin layer 1a, and colored beige with a grain pattern 5 formed during sheet molding. These materials 1a, 2a, and 3a were thermally laminated using a hot roll to obtain a laminate. The melting point is that of the non-foamed skin layer 1a,
The crosslinked highly foamed sheet 3a was higher than the crosslinked highly foamed sheet 2a, and could be thermally fused without the grain pattern 5 disappearing. This laminate was shaped using an ordinary press molding machine to obtain an automobile ceiling material with excellent heat resistance and a lightweight and sharp molded part.

(Example 2) In FIG. 3, the non-foamed skin layer 1c is
It is a sheet with a thickness of 0.2 mm obtained by extrusion molding an ethylene-propylene block copolymer having an MFR of 0.55, a melting point of 162°C, and a density of 0.905. The non-foamed skin layer 3c is made by blending 70 parts by weight of the resin used in the skin layer 1c with 30 parts by weight of linear low-density polyethylene (MFR 2.0, melting point 122°C, density 0.92). It is an extruded sheet with a thickness of 0.2 mm that is colored gray and has a grain pattern 5. These materials 1c, 2c, and 3c were thermally laminated using a hot roll to obtain a laminate. The melting point of the non-foamed skin layers 1c and 3c is higher than that of the crosslinked highly foamed sheet 2.
It was set higher than c, and the grain pattern 5 could be thermally fused without disappearing. This laminate was shaped using a normal press molding machine, and the heating conditions were such that the surface of the skin layer 3c facing the passenger compartment was
The heating conditions were set to be slightly weaker than that of the surface. The resulting automotive ceiling material was as good as that obtained in Example 1, but the surface facing the interior of the vehicle had a softer feel.

(Example 3) In FIG. 4, the non-foamed skin layer 1d is Example 2.
It is a 0.25 mm thick sheet made of the same resin as the skin layer 1b, and the crosslinked highly foamed sheet 2d is a 4mm foamed sheet with 40 times the foam obtained by the same manufacturing method as the crosslinked highly foamed sheet 2a used in Example 1. , non-foamed skin layer 3
d is the same as the skin layer 1d of the above example. In addition, the soft film 4d has an MFR of 1.3, a melting point of 153°C,
50 parts by weight of ethylene-propylene random copolymer with density 0.91, MFR 2.0, melting point 122℃, density 0.92
40 parts by weight of linear low density polyethylene,
This is a 0.08 mm thick sheet obtained by blending 10 parts by weight of an ethylene-propylene thermoplastic elastomer with an MFR of 0.5 and a density of 0.89. This laminate was made by extrusion lamination and shaped using a press molding machine. The surface of the convex mold facing toward the inside of the vehicle was provided with a grain pattern 5, and since it had air vent holes, the sharp grain pattern 5 could be applied at the same time as shaping. The resulting product had a softer surface than those obtained in Examples 1 and 2, and was an excellent automobile ceiling material.

(Effects of the invention) As described above, according to the automobile ceiling material of the invention, the cross-linked highly foamed sheet maintains a good balance between appropriate rigidity and flexibility, and has excellent moldability, heat resistance, etc. Also, by being suitable as a foam for automobile ceiling materials, it has a beautiful appearance as a ceiling material.
Deep and sharp thermoforming can be easily done without sacrificing the soft feel. In addition, there is no need for an extra decorative skin layer, and the cross-linked highly foamed sheet maintains a good balance between appropriate rigidity and flexibility. Since the suitability as a body can be obtained with a single layer of the crosslinked highly foamed sheet, it is possible to provide a lightweight and inexpensive automobile ceiling material with a three-layer structure.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and each of FIGS. 1 to 4 is a sectional view of a ceiling material for an automobile. 1a, 1b, 1c, 1d...non-foamed epidermis layer,
2a, 2b, 2c, 2d...Crosslinked highly foamed sheet,
3a, 3b, 3c, 3d...non-foamed skin layer, 4
b, 4d... Soft film, 5... Uneven pattern (grain pattern).

Claims (1)

[Scope of utility model registration request] Random copolymer of ethylene and propylene,
10 to 80 weight percent of one or more propylene copolymers selected from block copolymers or random block copolymers;
A non-foamed skin layer made of a propylene-based polymer is laminated on both sides of a cross-linked highly foamed sheet made of 20% by weight linear low-density polyethylene, and at least one of the skin layers has an uneven pattern such as a grain pattern. An automobile ceiling material characterized by having a pattern attached to it.