JPH0684055B2 - Interior material for automobile and method for manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automobile interior material used as an automobile ceiling material, a door material, and the like. More specifically, it has excellent sound absorption, heat resistance, and moldability. The present invention relates to an automobile interior material that can be easily integrally molded and a method for manufacturing the same.

(Prior Art) Various automobile interior materials have been conventionally proposed. Part 1
As one example, in Japanese Examined Patent Publication No. Sho 62-20003, after preheating a base material which is made by binding a fibrous substance with a thermoplastic resin or a thermoplastic resin to which a thermosetting resin is added, the base material is applied onto the base material.
Although a method of placing a surface covering material via an adhesive layer that cures at 120 ° C or lower and cold press molding is disclosed, when this method is used for cold press molding at 120 ° C or lower, the heat resistance of the base material is improved. There is a problem that the temperature decreases and the shape returns when exposed to high temperature after molding. This is because even if the base material is preheated to 120 ° C, the thermoplastic resin that is the binder of the fibrous material may not melt sufficiently, and in such a case, the binding between the fibers is not sufficiently relaxed. , This is due to residual strain stress due to deformation when press-molded as it is, and as a countermeasure against this, an adhesive layer that cures at 120 ° C or less is interposed between the base material and the covering material to improve heat resistance. It complements sex.

However, even if a curable adhesive layer is interposed between the base material and the facing material, the thickness of the adhesive layer is thin,
In comparison with this, the thickness of the base material is generally large, and the strain stress of the molding is built-in accordingly, so the prevention of the shape reversion when exposed to high temperature is not always guaranteed. The greater the thickness, the greater the residual stress, and the greater the possibility of problems with heat resistance.

Also, the fibers remain bound together with a binder,
Since the fibers do not have fluidity, that is, the positions of the fibers do not collapse, it is difficult for the fibers to fit into the mold surface during press molding, and high press pressure is required. There is also the problem of chipping.

(Object of the Invention) The present invention has been made in view of the above conventional circumstances,
An object thereof is to provide an automobile interior material having excellent sound absorption and heat resistance, and to provide a method for producing an automobile interior material which is easy to perform a molding operation and which enables simultaneous cold press forming of a cover material and a base material. Especially.

(Means for Solving Problems) A first invention of the present application is to provide a layer in which a thermoplastic resin binder and expandable microspheres are dispersed and foamed in a fiber-felt material mainly composed of glass fibers and needling. A second aspect of the present invention is an interior material for an automobile, which is characterized in that a heat-fusible adhesive layer having air permeability and a surface material layer having air permeability are sequentially laminated and molded. A fiber-felt material which is mainly made of is impregnated with a thermoplastic resin binder in which expandable microspheres are dispersed and dried, and then the surface of the fiber-felt material is provided with a breathable film-like or Apply a net-shaped heat-fusible adhesive, or
The melted heat-fusible adhesive is sprayed or applied so as to be breathable to form a base material, and the base material is heated to foam the expandable microspheres and melt the heat-fusible adhesive. Then, the method is a method for producing an interior material for an automobile, which comprises arranging an air-permeable covering material on the heat-fusible adhesive layer so as to face it or placing the covering material on the heat-melting adhesive layer so as to perform cold press molding.

The invention of the present application has the above-described configuration, but will be described in more detail below.

The fiber felt mainly composed of glass fibers used in the present invention is, for example, a glass fiber alone needling-ized, or the glass fibers are polyester fibers, polyvinyl chloride fibers, polyethylene fibers, synthetic fibers such as cotton, hemp, etc. ,
Natural fibers such as silk and regenerated fibers such as rayon are cut into appropriate lengths, and are singly or mixed, and the defibrated web is pressed with a roller and needle punched (needling). If necessary, a thin non-woven fabric may be arranged on one or both sides of the web for needling. And when the state of this fiber felt-like material is an automobile ceiling material, the thickness is usually 3 to 10
The unit weight per mm is preferably 200 to 1000 g / m ² .

The thermoplastic resin binder dispersed in this fiber felt-like material is an acrylic resin emulsion, vinyl chloride resin emulsion, polystyrene resin emulsion,
Acrylic ester resin emulsion and the like can be used, but it is preferable to use a mixed emulsion of two or more kinds including those having a softening temperature of 100 ° C or more, and further, an appropriate amount of synthetic rubber or natural rubber such as SBR or NBR is added. It is better to use.

The expandable microspheres are expandable polystyrene particles, or those which are expanded by heating such as thermally expandable microcapsules containing a hydrocarbon having a vinylidene chloride copolymer as a shell wall, and the foaming start temperature is Those having a temperature higher than the drying temperature are preferable, and those having a temperature of 100 ° C or higher are usually used. When the particle size is large in the impregnation and dispersibility in the fiber felt-like material, the impregnation and dispersibility decrease, so that it is preferable.
It is 200 μm or less, more preferably 100 μm or less.

Further, the expandable microspheres are preferably mixed with the resin emulsion which is the thermoplastic resin binder.

Then, the resin emulsion in which the expandable microspheres are mixed is impregnated into the fiber felt-like material and dispersed therein. The impregnation method may be a known method such as spraying, coating or dipping. Desirably, the method of immersing the fiber felt-like material in the tank of the resin emulsion in which the expandable microspheres are mixed is that the inside is uniformly impregnated.

The resin solid content in the resin emulsion in the present invention is preferably 10 to 60% by weight, including the expandable microspheres, and the amount of the thermoplastic resin binder with respect to the fiber felt is large, the rigidity of the obtained interior material is high. Although it is improved, the lightness and the sound absorbing property are lowered, and when it is reduced, the rigidity is lowered,
Usually, an amount of 20-80% by weight of fiber felt is preferred.

Further, the expandable microspheres may be added in an amount of several wt% to 50 wt% of the amount of the thermoplastic resin binder, and if added in large amounts, the foamed base material layer obtained will be bulky and the rigidity will be improved, but it will be expensive. When the expandable microspheres are used, the economical efficiency is impaired, so they should be selected appropriately.

A known method may be adopted as a method for drying the thus obtained sheet-like material, usually, drying by hot air drying, infrared / far-infrared heating, gas burner heating, high-frequency heating, or the like, or a heat roll or a hot plate. One method or two or more methods such as contact heating and drying with may be used in combination, but heating and drying are performed at a temperature at which the expandable microspheres do not at least foam or at a temperature at which foaming does not completely foam even when foamed. Should.

Then, in the fiber felt mainly composed of glass fibers, the expandable microspheres are impregnated and dispersed together with the thermoplastic resin, and on the dried sheet, a heat fusible adhesive layer having air permeability is provided. For sticking, a film-like or net-like heat-fusible adhesive having a well-known opening portion is placed on the sheet-like material, and the surface of the heat-fusible adhesive is heat-pressed and applied. how to.

As another method, it is possible to use a method in which a heat-fusible adhesive is melted and then sprayed and applied onto the sheet-like material.

Further, the amount of the heat-fusible adhesive is preferably ²⁰ to 150 g / m ² ,
The amount is more preferably 50 to 100 g / m ² , but should be increased or decreased depending on the condition of the surface of the base material and the condition of the back surface of the facing material.

The base material obtained in this manner, since the portions of the glass fiber-based fibers that come into contact with each other are partially bound by the thermoplastic resin, a communication structure is formed, and appropriate rigidity and air permeability are obtained. It has excellent sound absorption and moldability, and since the heat-fusible adhesive layer is provided on the surface of the base material, it is easy to handle.

Then, the base material is placed in a heating furnace and heated so that the expandable microspheres are foamed and the heat-fusible adhesive layer is completely melted, and most or all of the thermoplastic resin binder is melted. 140 ° C to 190 ° C is usually sufficient. Then, the base material is taken out of the heating furnace, and the breathable outer cover material is placed on the surface of the base material while the heat-sealable adhesive is in a molten state, and cold press molding is performed. The heated base material increases in thickness and becomes bulky due to foaming of the expandable microspheres, and most or all of the thermoplastic resin binder is melted to temporarily loosen the binding between the fibers, or The fibers will come off when they are undressed. Further, since the base material becomes bulky due to foaming, the density of the base material becomes low, and the fluidity of the fiber is further increased. Since the covering material is placed on the molten heat-fusible adhesive layer on the surface of the base material in this state taken out of the heating furnace and cold pressed, the fibers easily move along the mold shape, which is extremely excellent. Moldability is obtained.

Upon completion of the cold pressing, the thermoplastic resin binder is cooled and solidified again to bond the fibers in a stable state after being molded. By doing so, the stress due to the deformation of the press molding does not remain in the base material, and the mold does not return even when exposed to a high temperature after molding, that is, it has excellent heat resistance.

Further, the expandable microspheres start to be foamed by the heat in the heating furnace, but not all of the foaming is completed in the heating furnace, and the cold press molding is completed and continuously proceeds until the mold is removed. Therefore, the base material expands in the thickness direction even during the cold pressing and accurately follows the mold shape. In particular, even a complicated mold shape or fine irregularities can be molded with an accurate thickness and mold shape by the foaming pressure, and excellent moldability is exhibited.

Since the base material becomes bulky due to the foaming of the expandable microspheres, a molded product having a larger thickness than that of a non-foamed sheet having the same weight and having a higher rigidity can be obtained.

In the second invention, as described above, the thermally fusible adhesive of the base material heated in the heating furnace is arranged facing the breathable cover material, or placed and cooled. Press-mold. By doing so, the covering material does not receive the high temperature heat of the heating furnace, and therefore does not undergo deterioration or deformation due to heat. However, the covering material comes into contact with the adhesive in a molten state and receives the heat, but since it is only the bonding surface of the covering material and is immediately cooled by cold pressing,
The heat does not adversely affect the facing material.

The pressing time may be several tens of seconds due to the cold pressing. It should be noted that the surface covering material should take into consideration the sound absorbing property as well as the decorative property and the touch property, that is, it is a non-woven fabric, a knit cloth or the like that has air permeability, and further has air permeability to impart cushioning property. Those lined with polyurethane foam or the like are preferable.

(Example) The Example of this invention is described with drawing.

FIG. 1 shows the structure of an automobile interior material 1 of the present invention. In the figure, 2 is a layer formed by foaming expandable microspheres 2c dispersed with a thermoplastic resin binder 2b in a fiber felt-like material mainly composed of glass fibers 2a, and 3 is a heat-fusible adhesive having air permeability Layers 5 are facing materials. 4 is a base material.

2 to 4 are views showing an example of the manufacturing method of the present invention. Examples will be described below with reference to the drawings.

Fig. 2 Fig. 20 shows a fiber-felt-like material mainly composed of glass fibers.
m) 90 parts by weight and 10 parts by weight of polyester fiber (diameter 3 denier, fiber length 50-80 mm) are mixed and formed into a web, and needle punch (19 felt needle, needle density = 20 points / c)
m ² , needle penetration length: 14 mm), thickness about 6 mm, weight 550 g
The one with / m ² was used.

Reference numeral 21 denotes an emulsion tank in which 100 parts by weight of a polystyrene resin emulsion, 20 parts by weight of an acrylic resin emulsion, and expandable expandable microspheres containing a low boiling point hydrocarbon (foaming start temperature: about 120 ° C., Particle system: 15-50μ)
10 parts by weight, an appropriate amount of a viscosity adjusting agent, etc. were added thereto, and water was further added to dilute it to a solid content of about 30%. An emulsion 21a was put therein, and the felt 20 was passed through the emulsion 21a to impregnate the emulsion. Let

Next, the amount of the emulsion containing the expandable microspheres was adjusted to about 350 g / m ² in terms of solid content through the sandwich roll 22. Then, this was placed in a hot air drying device 23, and the water in the emulsion was dried by heating at about 100 ° C., and the fibers were partially bound by a thermoplastic resin binder that was impregnated and dispersed in the felt-like material. .

Then, a net-shaped heat-sealable adhesive (melting temperature of about 12
A base material 4 is completed by placing 0 ° C. and a basis weight of 50 g / m ² ) 3, heating it with an infrared heater 24, pressing it with a roll 25, and cutting it to a predetermined size with a cutter 26. FIG. 3 is a view showing a cross section of the base material 4. The obtained base material 4 has a thickness of about 4.
It has a laminated structure of 0 mm and a weight of 950 g / m ² .

This base material 4 is sent to the heating furnaces 27 and 27 'shown in FIG.
Heated to 0 ° C.

Next, the heated base material 4 was inserted between the cold press molding dies 28 and 28 'shown in FIG. 5, and the knit was lined with urethane foam having a foaming ratio of 30 times and a thickness of 3.0 mm. The urethane foam was placed or placed so as to face the heat-fusible adhesive 3 on the upper surface of the substrate 4, and the molds 28 and 28 'were clamped and pressed. The mold clamping pressure was 0.5 to 2.0 kg / cm ² , and the mold temperature was 60 ° C. and the mold clearance was 6.0 mm for 30 seconds.

FIG. 6 is a perspective view of the trimmed interior material after press molding.

Table 1 shows the physical properties and performance of the obtained interior material.

Comparative Examples in Table-1, except for 10 parts by weight of the expandable microspheres of the example, except that the mold clearance was changed to 4.0 m / m, the physical properties and performance of the interior material obtained in the same manner as in the example Show.

In Table 1, the mold shape-following property means that due to the action of the expandable microspheres, it is possible to mold with a uniform thickness without leaving a gap in the space inside the mold particularly in the curved portion. And ◎ is "good" that even a complicated bend can be molded with a uniform thickness
Shows the state. Δ indicates that there was a gap in the space inside the mold and the molding was uneven.

Regarding the adhesiveness with the skin material, ⊚ indicates that the urethane foam was broken and could not be peeled off, and the adhesiveness was good. The symbol “pseudo-adhesion” means a state in which the base material and the urethane foam are easily interfacially peeled, although they seem to be adhered at first glance.

The sound absorption (normal incidence sound absorption coefficient) is measured according to JIS A1405.
The higher the number, the better.

From Table 1, it is understood from the comparison between the examples of the present invention and the comparative examples that the products of the present invention are excellent in all of bending strength, mold shape followability, adhesiveness and sound absorption.

(Effect) Since the interior material obtained by the present invention has air permeability as the whole layer, it has excellent sound absorption, is lightweight, and has high rigidity due to foaming of the expandable microspheres.

Also, during press molding, the binding of fibers to each other is relaxed, and the base material expands in the thickness direction due to foaming pressure, and can also expand slightly in the planar direction, resulting in complex shapes and fine irregularities. It also has good followability and excellent moldability. After the molding, the fibers are re-bonded to each other, so that the stress due to the molding does not remain, and the fibers mainly composed of glass fibers reinforce, so that the interior material having excellent heat resistance can be obtained. It has the effect of achieving both moldability and heat resistance, which have been difficult to achieve in the past, and is suitable as a ceiling material or door material for automobiles.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the automobile interior material of the present invention, FIG. 2 is an explanatory view showing a part of the steps of the method for producing an automobile interior material of the present invention, and FIG. 2 is a sectional view of a base material manufactured by the process of FIG. 2, FIG. 4 is a sectional view showing a heating process, FIG. 5 is a sectional view showing a molding process, and FIG. 6 is a molded automobile interior. It is a perspective view of a material. 1 ... Automotive interior material, 2 ... Foamed layer 2a ... Glass fiber, 2b ... Thermoplastic resin binder 3 ... Heat-fusible adhesive layer, 4 ... Base material, 5 ... Exterior material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Sakamoto 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Tsugumi Sannomiya 1 Toyota Town, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Kazuo Ito 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd.

Claims (2)

[Claims] 1. A layer in which a thermoplastic resin binder and expandable microspheres are dispersed and foamed in a glass felt-needed fiber felt-like material, and a heat-fusible adhesive having air permeability. An automobile interior material comprising a layer and a breathable surface material layer sequentially laminated and molded. 2. A glass fiber-based needling fiber felt material is impregnated with a thermoplastic resin binder in which expandable microspheres are dispersed and dried, and then the surface of the fiber felt material is A film-like or net-like heat-fusible adhesive having air permeability is attached, or a melted heat-fusible adhesive is sprayed or applied so as to be breathable to form a base material. The material is heated to foam the expandable microspheres and melt the heat-fusible adhesive, and then a breathable cover material is applied to the heat-fusible adhesive layer.
A method of manufacturing an interior material for an automobile, which comprises arranging them to face each other or placing them on one another and performing cold press molding.