JP2569806B2 - Vehicle interior material and molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention uses a vehicle interior material and a molding method, particularly a vehicle interior material having a pad material and a molding die having an upper mold and a lower mold. The present invention relates to a method for forming an interior material for a vehicle.

[Conventional technology and its problems]

For example, vehicle interior moldings having pad materials are used for vehicle interior moldings such as dashboards.
As a pad material used for such a vehicle interior material, for example, a pad material made of a polyolefin-based resin foam is widely used.

As a molding method of the vehicle interior material provided with the pad material, a known method such as an integral molding method and a vacuum compression method is used. Also recently, energy saving, labor saving,
The hot stamping molding method has begun to be used as a molding method that can rationalize the use of an adhesive or the like and has a good quality stability of vehicle interior materials.

However, when the interior material for a vehicle is molded at a high pressure by these molding methods, the thickness of the interior material decreases, and so-called settling may occur. This is because the pad material causes settling due to high pressure. In the case of the integral molding method or the hot stamping molding method, since the pad material comes into contact with the high-temperature base resin, the foam bubbles are broken. As a result, there is a problem that surface roughness such as unevenness occurs on the surface of the vehicle interior material.

As a means for solving such a problem, a configuration in which a foam having a low expansion ratio is used as the pad material can be considered, but the pad material having a low expansion ratio has insufficient cushioning properties and flexibility. Further, a configuration in which a protective film is laminated on the surface of a pad material has been proposed (for example, see Japanese Patent Application Laid-Open No. 62-181113). However, in this case, it takes time and effort to laminate the protective film on the pad material, which increases the cost of the vehicle interior material.

An object of the first invention is to provide an interior material for a vehicle in which settling and surface roughness occurring during molding processing are improved, and which have sufficient cushioning and flexibility.

It is an object of a second invention to provide a method of molding a vehicle interior material according to the first invention.

[Means for solving the problem]

The vehicle interior material according to the first invention has a gel fraction of 2 to 75.
%, The expansion ratio is 2 to 15 times, the thickness of the first polyolefin resin foam is 0.1 to 6.0 mm, and the stress at 25% compression is 0.2 kg /
and cm ² or more second formation diaphragm ratio bonding the polyolefin resin foam is 0.40 or more pad material, a base material is laminated on the first polyolefin resin foam of the pad material, the pad material And a skin material laminated on the polyolefin resin foam.

Outline of Vehicle Interior Material FIG. 1 shows an example of a vehicle interior material of the present invention. The vehicle interior material 1 mainly includes a base material 2, a pad material 3 laminated on the base material 2, and a skin material 4 laminated on the pad material 3.

The pad material 3 is made of a first polyolefin resin foam 3A
And the second polyolefin-based resin foam 3B. The pad material 3 is laminated on the base material 2 on the first polyolefin resin foam 3A side. The skin material 4 is laminated on the second polyolefin resin foam 3B side.

Pad material The polyolefin resin used for the first and second polyolefin resin foams constituting the pad material includes:
Examples thereof include a polyethylene resin, a polypropylene resin, and a mixed resin of a polyethylene resin and a polypropylene resin.

Examples of the polyethylene resin include a low-pressure method, a medium-pressure method, a polyethylene resin having a density of 0.900 to 0.965 g / cc produced by a high-pressure method, a linear polyethylene resin having an α-olefin copolymerized such as butene and pentene, and ethylene. -Vinyl acetate copolymer resin, ethylene-acrylate copolymer resin and the like. Each of these polyethylene resins may be used alone or 2
They may be used as a mixture of more than two species.

Examples of the polypropylene-based resin include a propylene homopolymer, a block copolymer resin of α-olefin such as ethylene and butene and propylene, a random copolymer resin, and a random-block copolymer resin. These polypropylene resins may be used alone or in combination of two or more.

The polyolefin resin may be mixed with a resin other than the polyolefin resin, for example, a petroleum resin or a polystyrene resin. Further, a stabilizer, a thickener, a lubricant, a coloring agent, an inorganic compound such as titanium oxide and talc may be added to the polyolefin resin.

The first and second polyolefin-based resin foams used for the pad material are produced, for example, by cross-linking the polyolefin-based resin or at the same time as the cross-linking, while heating the foamed material to a temperature higher than the decomposition temperature of the foaming agent. In addition, as a crosslinking method of the polyolefin resin, an arbitrary method such as an ionizing radiation crosslinking method and a chemical crosslinking method is used.

The first polyolefin resin foam used for the pad material has a gel fraction of 2 to 75%, preferably 30 to 55%, and more preferably 40 to 50%. When the gel fraction is less than 2%, the heat resistance of the pad material decreases. Conversely, the gel fraction
If it exceeds 75%, the elongation of the pad material is reduced, and drawing is difficult. The gel fraction was 0.1 g of the foam sample.
Is a value indicated by% by weight of the insoluble matter remaining after immersion in tetralin at 130 ° C. for 3 hours.

The first polyolefin resin foam has an expansion ratio of 2 to 15 times, preferably 8 to 13 times, and more preferably 9 times.
~ 10 times. If the expansion ratio is less than 2, it becomes difficult to reduce the weight of the vehicle interior material. On the other hand, when the expansion ratio exceeds 15 times, the bubbles are likely to break when they come into contact with a melt of the base material described later.

Further, the first polyolefin resin foam has a thickness of
It is 0.1 to 6.0 mm, preferably 1 to 2 mm. When the thickness is less than 0.1 mm, the effect of preventing unevenness generated on the surface of the vehicle interior material is reduced. Conversely, if the thickness exceeds 6.0 mm, the molded shape of the vehicle interior material will be reduced.

The second polyolefin resin foam used for the pad material has a stress at the time of 25% compression of 0.2 kg / cm ² or more, desirably.
0.4 kg / cm ² or more. If the stress at 25% compression is less than 0.2 kg / cm ² , the foam becomes too soft, and the foam loses its stiffness. The stress at the time of 25% compression is a value of the stress of the foam measured by compressing the foam by 25% using a compression tester.

Further, the second polyolefin resin foam preferably has a gel fraction of 10 to 60%, more preferably 30 to 45%. When the gel fraction is large or small, the same problem as in the case of the first polyolefin-based resin foam may occur. The expansion ratio of the second polyolefin resin foam is 20
~ 40 times, more preferably 20-30 times. When the foaming ratio is small, it becomes difficult to obtain a vehicle interior material having sufficient cushioning, flexibility and tactile sensation. Conversely, if the magnification is large, the stress may be small and the formability may be reduced. Further, the thickness of the second polyolefin-based resin foam is preferably 1 to 6 mm, more preferably 1 to 3 mm. When the thickness is small, it becomes difficult to obtain a vehicle interior material having sufficient cushioning and tactile sensation. Conversely, if the thickness is large, the molded shape may be reduced.

The pad material used for the vehicle interior material of the present invention is obtained by laminating the first polyolefin resin foam and the second polyolefin resin foam. Examples of the bonding method include a method of fusing by a hot air method or a flame method, and a method of using an adhesive. When an adhesive is used, for example, a water-soluble adhesive such as a polyester-based or polyurethane-based solvent-based adhesive or a modified polyolefin-based resin is used as the adhesive. When bonding the foams together, it is desirable that the bonding surface be smooth. If the bonding surface is not smooth, blistering may occur at the bonded portion during molding.

The thickness of the pad material varies depending on the use site of the vehicle interior material, but is usually 2 to 8 mm. If the thickness of the pad material is small, a vehicle interior material having sufficient cushioning properties and tactile sensation cannot be obtained. Conversely, when the thickness of the pad material is large, the moldability of the vehicle interior material is reduced.

Also, the forming draw ratio of the pad material is 0.40 or more, preferably
0.55 or more. If the forming draw ratio is less than 0.40, it becomes difficult to obtain a vehicle interior material having a desired shape. In addition, the value of the forming draw ratio is a value measured as follows. Using a cylindrical mold capable of changing the depth H (cm) with respect to the diameter L (cm), the sample is heated to 120 to 200 ° C. and vacuum-formed to produce a molded product. The maximum depth H of the mold when there is no break in the obtained molded product is measured, and the molding draw ratio is determined using the following equation.

Molding draw ratio = H / L Substrate The substrate used for the vehicle interior material of the present invention is, for example, a polyolefin resin having a melt index of about 1 to 60 containing polyethylene or polypropylene as a main component. Other resins such as petroleum resin and acrylonitrile-butadiene-styrene (ABS) resin may be added to the polyolefin resin. These resins are added in a range that does not hinder the flowability of the polyolefin resin. Further, an inorganic compound such as talc and calcium carbonate, a coloring agent, a stabilizer and the like may be added to the polyolefin-based resin.

Further, a rigid urethane foam may be used for the base material. In this case, the expansion ratio of the rigid urethane foam is 2
~ 10 times is desirable. If the expansion ratio is too large, the shape retention of the vehicle interior material is reduced.

It is to be noted that a particularly preferable substrate used in the present invention is a substrate made of a polypropylene resin.

The base material is laminated on the pad material by using, for example, a polyester-based or polyurethane-based solvent-based adhesive or a water-soluble adhesive such as a modified polyolefin-based resin. On this occasion,
The base material is laminated on the first polyolefin resin foam side of the pad material. The base material may be laminated on the pad material at the same time as the molding of the vehicle interior material, as in a second invention described later.

Skin material The skin material used for the vehicle interior material of the present invention includes:
For example, a polyvinyl chloride sheet, a polyvinyl chloride / ABS mixed sheet, a thermoplastic resin elastomer sheet, a knitted fiber, a nonwoven fabric and the like can be mentioned. These skin materials are, for example, polyester-based or polyurethane-based solvent-based adhesives,
Alternatively, the pad is laminated on the pad material using a water-soluble adhesive such as a modified polyolefin resin. At this time, the skin material is laminated on the second polyolefin resin foam side of the pad material. When the skin material is laminated on the first polyolefin-based resin foam side, a vehicle interior material having sufficient cushioning properties and tactile sensation cannot be obtained.

Use of the vehicle interior material The vehicle interior material of the present invention is formed by an integral molding method, a vacuum molding method,
It is formed into a desired shape using a method such as a hot stamping molding method. And, for example, the dashboard,
Used for door trim, molded ceiling, seat back trim, rear quarter trim, center pillar pad, etc.

******** The method for molding a vehicle interior material according to the second invention is a method for molding a vehicle interior material using a molding die having an upper mold and a lower mold. This method of forming an interior material for a vehicle includes the following steps.

(A) a first polyolefin resin foam having a gel fraction of 2 to 75%, an expansion ratio of 2 to 15 times, and a thickness of 0.1 to 6.0 mm;
A pad material having a molding draw ratio of 0.40 or more, which is bonded to a second polyolefin resin foam having a stress at the time of% compression of 0.2 kg / cm ² or more.

(B) Laminating a skin material on the second polyolefin resin foam of the pad material.

(C) A base material is arranged on the lower mold, and a pad material on which a skin material is laminated is arranged between the upper mold and the lower mold such that the skin material faces the upper mold.

(D) Obtaining a molded product in which a base made of a base material is laminated on a pad material by closing the mold.

Next, the method for forming a vehicle interior material of the present invention will be specifically described.

First, a pad material is prepared. The pad material used in the present invention is the same pad material used for the vehicle interior material according to the first invention.

Next, a skin material is laminated on the pad material. This skin material,
This is the same skin material as used in the vehicle interior material according to the first invention. The skin material is laminated on the surface of the pad material on the side of the second polyolefin-based resin foam. An adhesive is used for laminating the pad material and the skin material. As the adhesive, for example, a polyester-based or polyurethane-based solvent-based adhesive,
Alternatively, a water-soluble adhesive such as a modified polyolefin resin is used. Note that these adhesives are applied to the surface of the pad material or the back surface of the skin material using, for example, a gravure roll method or a doctor knife method. The amount of the adhesive applied is preferably about 30 to 120 g / m ² .

Next, the base material is placed on the lower mold of the molding die. This base material is a base material used for the vehicle interior material of the first invention,
For example, a polypropylene resin is used. The base material is
On the lower mold, for example, it is arranged in a molten state like a dumpling or a sheet. The temperature of the base material varies depending on the material, but is usually 150 to 250 ° C.

At the same time, the pad material on which the skin material is laminated is arranged between the upper mold and the lower mold. At this time, the pad material is arranged so as to face the upper mold, and the surface of the pad material on the first polyolefin resin foam side is opposed to the base material arranged in the lower mold. The pad material is placed on the mold in a heated state. The heating temperature is usually from normal temperature to 200 ° C.

Subsequently, the mold is closed with the pad material arranged. That is, the upper mold is pressed against the lower mold. Thereby, the pad material is pressed against the base material, and the base material is laminated on the pad material. Then, a vehicle interior material having a desired shape is obtained. The pressure when closing the mold is usually 0.5
It is ~200kg / cm ^2.

In the present invention, the base material in the molten state comes into direct contact with the pad material, but the base material is in contact with the first polyolefin-based resin foam having a small expansion ratio. Therefore, the second polyolefin-based resin foam on which the skin material is laminated is less likely to cause cell destruction. As a result, surface roughness such as unevenness is less likely to occur on the surface of the skin material, and the cushioning property and flexibility are not easily reduced.

〔The invention's effect〕

According to the first invention, it is possible to obtain an interior material for a vehicle in which settling and surface roughness are improved, and which have sufficient cushioning and flexibility.

In the second invention, since the padding material of the first invention is used, it is possible to obtain a vehicle interior material having a desired shape with improved settling and surface roughness, and having sufficient cushioning and flexibility. it can.

〔Example〕

Examples 1 to 4 A gel fraction of 50% by weight of a polyolefin resin composed of 80% by weight of a polypropylene resin randomly copolymerized with 5% by weight of ethylene and 20% by weight of a polyethylene resin having a density of 0.930 g / cc and a melt index of 8 %, A foaming ratio of 10 times, and a foam 1.5 mm thick. On the other hand, a foam B having a foaming ratio of 20, 25, 30, and 40 times and a thickness of 1.5 mm was prepared from the same polyolefin resin as used for the foam A. The stress at 25% compression of the foam B was as shown in Table 1.

The obtained foam A and foam B were bonded together at 240 ° C. by a hot air method to prepare a pad material. A soft polyvinyl chloride sheet having a thickness of 0.45 mm was bonded to the pad material using a polyester-based two-component adhesive to obtain a laminated material.

Next, a polypropylene resin (melt index 10) in a molten state at 220 ° C. extruded in a sheet shape from the extruder by a T-die method was placed in a lower mold of a compression molding machine.
At the same time, the laminated material cut into a square of 20 cm was arranged in a compression molding machine such that the pad material surface faced the molten polypropylene resin, and molded at a pressure of 58 kg / cm ² to produce a vehicle interior material. . About the obtained vehicle interior material, the unevenness state and tactile sensation on the surface of the skin material were examined. The results are shown in Table 1.

Comparative Examples 1 to 5 Using the same polyolefin resin as used in Examples 1 to 4, the gel fraction was 35%, the thickness was 3 mm, and the expansion ratio was 1 each.
Foams of 0, 20, 25, 30, and 45 times were produced.

Using the obtained foam, an interior material for a vehicle in which a skin material and a base material were laminated was manufactured in the same manner as in Examples 1 to 4. The same characteristics as in Examples 1 to 4 were examined for the obtained vehicle interior materials. The results are shown in Table 1.

The evaluation criteria are as follows.

Irregularities on the surface of the skin material ○: No irregularities.

X: There are irregularities.

Tactile: Good.

：: practical.

X: Poor.

Examples 5 and 6 70% by weight of a polypropylene resin copolymerized with 2% by weight of ethylene, a density of 0.920 g / cc and a melt index of 2
A foam C having a gel fraction of 45%, an expansion ratio of 10 and a thickness of 1 mm was prepared using a polyolefin resin comprising 30% by weight of a linear polyethylene resin. A gel fraction of 35% was obtained using a polyolefin resin composed of 60% by weight of a polypropylene resin copolymerized with 5% by weight of ethylene and 40% by weight of a linear polyethylene resin having a density of 0.930 g / cc and a melt index of 8. A foam D having an expansion ratio of 25 times and a thickness of 2 mm was prepared. In addition, low-density polyethylene with a density of 0.923 g / cc and a melt index of 3.7 is 35% gel fraction from resin,
A foam E having an expansion ratio of 20 times and a thickness of 2 mm was prepared.

The obtained foams C, D, and E were bonded in the combinations shown in Table 2 to prepare pad materials. Note that a thermosetting polyester-based adhesive was used for bonding. A soft polyvinyl chloride sheet having a thickness of 0.4 mm was laminated using a thermosetting polyurethane adhesive before the foam D or foam E of the obtained pad material to obtain a laminated material.

Next, 30 g of a polyolefin resin in a molten state at 185 ° C. consisting of 80% by weight of a polypropylene resin and 20% by weight of a polyethylene resin was placed in a lower mold of a compression molding machine. At the same time, the composite material cut into a 20 cm square was placed so that the foam C faced the molten polyolefin resin. Then, molding was performed under a pressure of 55 kg / cm ² to produce an interior material for a vehicle.

The characteristics of the obtained vehicle interior material were examined in the same manner as in Examples 1 to 4. The results are shown in Table 2. The evaluation criteria are the same as in Table 1.

Comparative Examples 6 to 8 The same foams C, D, and E as those used in Examples 5 and 6 and each having a thickness of 3 mm were used alone, and the vehicle interior was used in the same manner as in Examples 5 and 6. Lumber was manufactured.

The characteristics of the obtained vehicle interior material were examined in the same manner as in Examples 5 and 6. Table 2 shows the results. The evaluation criteria are the same as in Table 1.

[Brief description of the drawings]

The figure is a partial longitudinal sectional view of an interior material for a vehicle according to an example of the first invention. 1 ... vehicle interior material, 2 ... base material, 3 ... pad material, 3A
... 1st polyolefin resin foam, 3B ... 2nd polyolefin resin foam, 4 ... skin material.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-222937 (JP, A) JP-A 64-7524 (JP, U) JP-A 62-122748 (JP, U)

Claims (2)

(57) [Claims] 1. A gel fraction of 2 to 75% and an expansion ratio of 2 to 15
The drawing ratio of the first polyolefin resin foam having a thickness of 0.1 to 6.0 mm and the second polyolefin resin foam having a stress at the time of 25% compression of 0.2 kg / cm ² or more is 0. .
40 or more pad materials, a base material laminated on the first polyolefin resin foam of the pad material, and a skin material laminated on the second polyolefin resin foam of the pad material. Vehicle interior materials provided. 2. A method of molding an interior material for a vehicle using a mold having an upper mold and a lower mold, wherein the gel fraction is 2 to 75%, the expansion ratio is 2 to 15 times, and the thickness is 0.1.
A pad material with a drawing ratio of 0.40 or more is prepared by laminating a first polyolefin resin foam of up to 6.0 mm and a second polyolefin resin foam with a stress at 25% compression of 0.2 kg / cm ² or more. And laminating a skin material on the second polyolefin resin foam of the pad material, and disposing a base material on the lower mold, and between the upper mold and the lower mold. A base material made of the base material is stacked on the pad material by disposing the pad material on which the skin material is stacked so that the skin material faces the upper mold, and closing the mold. And a method for forming an interior material for a vehicle, comprising: