KR970011788B1 - Method for producing interior finishing material in atomobiles - Google Patents

Abstract

None.

Description

Automotive interior materials and manufacturing method thereof

1 is a cross-sectional view showing an embodiment of the interior material for automobiles according to the present invention,

2 is a diagram illustrating a method of manufacturing the interior material according to the present invention,

3 is a cross-sectional view of the laminate produced by the method of FIG.

4 is a cross-sectional view showing a step of heating a laminated plate,

5 is a cross-sectional view of the molding process,

6 is a perspective view of an interior material formed in accordance with the present invention.

* Explanation of symbols for main parts of the drawings

1 interior material 2 support layer

3: adhesive film 4: laminated sheet

5: surface material 20: glass fiber sheet

21: emulsion zone 24: infrared heater

26: cutter 23: drying device

221,222,223,251,252: Roller 27,27 ': Heating Furnace

28,28 ': Press molding tool270,270': Heater

The present invention relates to automotive interior materials such as headlining, doors and the like. Specifically, the present invention relates to an interior material which can be easily manufactured by a one-piece molding method and has excellent sound absorption characteristics, deformation resistance against heat and formability. Moreover, the present invention relates to a method for manufacturing a vehicle interior having the above excellent characteristics.

Automotive interior materials, such as headlining, have been proposed and manufactured for a long time. For example, Japanese Patent Laid-Open No. 62-200003 describes a method of manufacturing the following interior materials, for example. First, the fibers are combined with a thermoplastic resin or a mixture of thermoplastic and thermosetting resins to produce a sheet. The sheet (e.g., support layer) is preheated to about 120 [deg.] C. and deposited thereon via a thermosetting adhesive layer capable of curing the surface material at a temperature of 120 [deg.] C. or lower, and then the laminate is subjected to cold compression molding. This method heats the support layer at a relatively low temperature, such as approximately 120 ° C., so that no degradation such as surface material deteriorates at high temperatures. However, the thermoplastic resin acting as a binder is not sufficiently melted at the above-mentioned low temperatures, so that the bonds between the fibers are not sufficiently released.

When compression-molding the heated support layer, the stress caused by the deformation of the support layer remains. Therefore, when the molded article is kept at a high temperature, the molded article tends to return to its original form. In this method, in order to prevent the deformation of the molded article caused by residual stress, the adhesive layer which can be hardened at a comparatively low temperature of 120 degrees C or less is provided. However, since the adhesive layer is very thin compared to the thickness of the support layer, the above-described prevention of deformation is insufficient. When the thermoplastic resin is incorporated into the support layer, the degree of deformation is less than that occurring in the support layer containing only thermoplastic resin, but in this case, a sufficient effect cannot be obtained. In particular, when the support layer is thick, the stress generated in the support layer becomes large, and deformation occurs better.

Moreover, in the above method, since the thermoplastic resin serving as the binder is not completely melted, the support layer is molded together with the fibers bonded to the binder. When press-molding the support layer, the worse the fluidity of the fiber, the worse the structure of the support layer. That is, the fibers do not move easily. Therefore, higher pressure is required for molding because the support layer is difficult to form accurately in the form of a mold. Therefore, this method has the disadvantage that the molding process cannot be performed accurately.

Solving the various disadvantages and disadvantages of the prior art described above, the automotive interior material of the present invention is a needled glass fiber sheet containing a thermoplastic resin binder, the support layer of the needled glass fiber mainly composed of glass fibers; It consists of an air permeable heat sealability provided on said support layer, an adhesive layer and an air permeable surface layer provided on said adhesive layer, said support layer further comprising foamed microbeads.

Foamed microbeads are formed by heat treatment of the expandable microbeads.

Method for producing a vehicle interior material comprising the steps of providing a needled glass fiber sheet composed mainly of glass fiber; Dispersing a thermoplastic resin binder and expandable microbeads in the needled glass fiber sheet to form a support layer; Forming an air permeable, heat sealable adhesive layer on the surface of the support layer, heating the obtained bilayer laminate to expand the expandable microbeads and to melt the heat sealable adhesive; Loading an air permeable surface material on the surface of the adhesive layer and cold compression molding the obtained three-layer laminate.

In a preferred embodiment, the expandable microbeads are thermoplastic resin particles containing a blowing agent.

In a preferred embodiment, the thermoplastic resin binder is contained in an amount of 20 to 80 parts by weight per 100 parts by weight of the glass fiber sheet, and the expandable microbead is contained in an amount of 2 to 50 parts by weight per 100 parts by weight of the thermoplastic resin binder.

In a preferred embodiment, the needled glass fiber sheet further contains organic fibers.

Accordingly, the present invention provides (1) a vehicle interior material that does not deform upon heating and has excellent sound absorption properties, (2) provides a method for easily manufacturing a vehicle interior material having the above excellent properties, and ( 3) By simultaneously cold pressing the surface material and the support layer, the object of providing a method for producing a vehicle interior material having the above excellent properties can be achieved.

By referring to the accompanying drawings, those skilled in the art can better understand the present invention, and various objects and advantages will be clearly understood.

The glass fiber sheet used in the present invention is produced mainly from glass fibers, and contains organic fibers as necessary. Examples of the organic fibers include synthetic fibers such as polyester fibers, polyvinyl chloride fibers, polyethylene fibers and the like; Natural fibers such as cotton, linen, silk and the like and recycled fibers such as rayon fibers and the like.

The glass fiber sheet is obtained by needling a glass fiber mat, for example. Alternatively, the fiberglass sheet can be produced as follows. First, at least one of the aforementioned organic fibers, precut to a suitable length, is fibrillated and mixed with glass fibers to form a web. The web is then compressed by rollers and needle punched. Needling can be practiced by loading a thin nonwoven fabric on one side of the web or on both sides of the web.

Suitable of the above glass fibers are those having a diameter of 5 to 15 mu m, preferably 8 to 12 mu m, and a length of 2 to 20 cm. It is preferable that the fiber having a length of 4 to 8 cm is dispersed in the range of 50 to 90% of the glass fibers constituting the support layer. The obtained preferred glass fiber sheet has a thickness of 3 to 10 mm and a weight of 200 to 1000 g / cm ² .

The organic fibers are preferably made of polyester having a denier of 2 to 6 and a length of 2 to 20 cm. It is preferred that polyester fibers having a length of 4 to 8 cm are dispersed in the range of 50 to 90% of all polyester fibers.

Examples of the thermoplastic resin binder used in the present invention include acrylic resins (including acrylate resins), vinyl chloride resins, polystyrene resins, and the like. It is preferable to use at least 2 types of resin including resin whose softening temperature is 100 degreeC or more. It is preferable to add synthetic rubber or natural rubber such as SBR, NBR, etc. to the resin in a suitable amount. These resins impart rigidity and toughness to the support layer. The thermoplastic resin binder is usually used for impregnation of the glass fiber sheet described above in emulsion form.

The resin binder is used in an amount of 20 to 80 parts by weight per 100 parts by weight of the glass fiber sheet as a solid content. When the amount of the resin binder is used in an excessive amount, the resulting interior material is improved in rigidity, but its sound absorption property is deteriorated, and the weight of the interior material is increased. On the other hand, when the resin binder is used in less than 20 parts by weight, the rigidity of the interior material is lowered.

The expandable microbeads used in the present invention are particles made of a thermoplastic resin containing a blowing agent. For example, commercially available expandable polystyrene microbeads can be used, in which blowing agents such as propane, butane, pentane petroleum ether and the like are dispersed. Alternatively, thermally-foamable microcapsules made of vinylidene chloride copolymer or the like may be used, in which hydrocarbon liquids (e.g., pentane, hexane, heptane, etc.) boiling at low temperatures are contained. Useful effervescent microbeads are microbeads having a higher foam onset temperature (eg, the temperature at which foaming takes place) than those used in the drying step of the support layer described below. Generally, microbeads with a foam start temperature of at least 100 ° C are used. These expandable microbeads are mixed with the above-mentioned binder, which is impregnated in the emulsion form, as described below, and then dispersed in a glass fiber sheet. Expandable microbeads with an excessively large particle diameter have poor dispersibility. The diameter of the blowing agent microbeads is 200 µm or less, preferably 100 µm or less, and more preferably 20 to 30 µm. The foaming ratio of the expandable microbeads is preferably 40 to 80. The blowing agent microbeads are preferably used in an amount of 2 to 50 parts by weight per 100 parts by weight of the thermoplastic resin binder. If the foaming microbead is used in a smaller amount than this, the molded article obtained by deterioration of the formability of the support layer tends to deform at high temperatures. If the foamed microbead is used in excess, the volume of the foamed support layer becomes excessively large, resulting in insufficient rigidity. Moreover, expandable microbeads have the disadvantage of being expensive.

The binder and effervescent microbeads described above are typically used in the form of emulsions with a solids content of 10 to 60% by weight, based on their mixing amount.

Examples of the heat sealable adhesive used in the present invention are conventional heat sealable adhesives such as amide based adhesives, ethylene-vinylacetate copolymers, adhesives made of polyisobutylene, and the like. The melting temperature of the above-mentioned adhesive agent is 85-130 degreeC.

The surface material used in the present invention is an air-permeable sheet, which has a sound absorbing property. Moreover, nonwoven or knit fabrics are commonly used to give the desired decorative effect and pleasant feel. In particular, in order to impart cushioning properties, a sheet having an air permeable polyurethane foam attached to the back side is preferable.

In order to manufacture the automotive interior material according to the present invention, for example, the glass fiber sheet is impregnated into an emulsion zone containing the thermoplastic resin and the expandable microbead. This sheet can be impregnated into the emulsion zone by application, spraying, or dipping. Most preferred is the dipping method. In this method, a support layer having a thermoplastic resin and expandable microbeads uniformly dispersed in a glass fiber sheet can be obtained. For example, the support layer obtained by the above immersion method is dried by a suitable method. The drying process can be a normal drying process. For example, a heating process using hot air, infrared rays or ultraviolet rays, a gas burner, a high frequency heater, or the like can be used. Alternatively, the sheet can be dried in contact with a heated roll, hot plate or the like. The drying process can be carried out in one step or a combination of two or more in total. The drying temperature should be the temperature at which the expandable microbeads do not foam or the temperature at which the microbeads begin to foam somewhat, but not at all.

Thereafter, a heat sealable binder is attached to the surface of the obtained support layer. For example, the adhesive is partially attached (eg in a stripe or lattice pattern) such that the adhesive layer formed by spraying on the surface of the support layer is air permeable throughout. Typically, a commercially available heat-adhesive adhesive in the form of a film or net with openings is attached onto the support layer, heated and then pressed into an adhesive layer in the form of a support layer.

The heat sealable adhesive is used in an amount of 20 to 150 g, more preferably 50 to 100 g per m ² of substrate. The amount of adhesive may increase or decrease depending on the type of material and the surface drying and surface material of the support layer.

In the support layer, a portion of the fibers (mainly glass fibers) adhering to each other is partially bonded with the thermoplastic resin, so that the support layer has a continuous structure. Thus, the support layer has both rigidity and air permeability. The heating and molding step to be described later can be easily performed by using a laminate composed of the above-described support layer and a heat-adhesive adhesive.

The laminate of the support layer and the heat sealable adhesive is heated in an oven. The heating temperature is a temperature at which the above-mentioned expandable microbeads foam, the heat-sealable adhesive layer melts completely, and the thermoplastic resin binder melts almost or all. Typically, the temperature is from 140 to 190 ° C. It is preferable to make heating time into 25 to 90 minutes. The heated laminate is taken out of the oven, and then the heat-adhesive adhesive is loaded with the surface material on the surface of the adhesive layer while maintaining the molten state, followed by cold compression molding. Compression molding can be performed sufficiently within 10 seconds. The heated support layer becomes bulky due to the foaming of the expandable microbeads, increasing in thickness, and the thermoplastic resin binder melts almost or completely. Thus, the mutual bonds between the fibers are loosened or loosened so that the fibers are fluid.

In addition, since the support layer increases in volume by foaming, the density of the support layer is lowered and the fluidity of the fiber is further increased. By removing the support layer from the furnace and then loading the surface material on the support layer and cold pressing, the fiber is easily moved according to the shape of the mold, thereby having extremely good moldability.

The expandable microbeads contained in the support layer begin to foam when the laminate is heated in the furnace. This foaming is not entirely pigmented in the furnace and continues until the end of the cold compression process and the molded article is removed from the mold. Therefore, even during cold compression molding, since the support layer is foamed in the thickness direction, it is possible to create a shape that is suitable for the shape of the mold. As a result, due to the pressure resulting from the foaming of the microbeads, molding having excellent moldability can be performed, and a molded article having an accurate thickness and shape can be produced even when the mold has a complicated shape or minute irregularities.

Once the cold compression molding is complete, the thermoplastic binder is cooled again and solidified to allow the fibers to bond together in a stable state to form a molded article. Therefore, in the support layer of this invention, the stress which arises by deformation at the time of press molding does not generate | occur | produce. Therefore, the obtained molded article does not return to its original state even when exposed to high temperature. In other words, the molded article is excellent in heat resistance.

Since the foam support layer of the obtained molded article increases in volume due to the foaming of the expandable microbeads, the foamed support layer becomes thicker than the non-foamed sheet having the same weight. As a result, the molded article becomes more rigid.

In the present invention, only the laminate made of the support layer and the heat-adhesive adhesive is heated as described above. Although the surface material is heated by contact with the molten adhesive, it is only the laminated surface that is heated, and the material is then immediately cooled by cold compression. As such, the quality or shape is not changed by heating.

The interior materials produced by the present invention are generally air permeable, excellent in sound absorption properties, and made rigid by the foaming of lightweight and expandable microbeads.

Since the mutual bonding between the fibers is loose in the compression molding process, and because the expansion pressure not only expands the supporting layer in the thickness direction, but also partially expands in the plane direction, excellent moldability can be obtained. Even if a mold having a complicated shape or minute irregularity is used, the molding can be performed accurately. The fibers recombine with each other upon completion of the molding to prevent any stress caused by the molding. In addition, fibers composed mainly of glass fibers reinforce the entire molded article. In this manner, an interior material having excellent resistance to deformation at high temperatures can be obtained. Automobile interior materials produced by the present invention are suitable for use as headlining or doors of automobiles.

The following examples illustrate preferred embodiments of the present invention, which do not limit the present invention.

Example 2

2 is a view illustrating a laminated sheet manufacturing apparatus of the present invention composed of a support layer and a heat sealable adhesive. The apparatus includes a continuous sheet conveying roll 221 and 223, an emulsion tank 21 for impregnating the sheet with the expandable microbead-containing resin emulsion zone 21a, a high temperature air drying apparatus 23, an infrared heater ( 24, a compression roller 252, and a cutter 26 is included. The sheet guide roller 222 is provided in the emulsion zone 21 in which the glass fiber sheet 20 is impregnated with the emulsion zone 21a. Emulsion absorption is controlled by a roller 223 provided downstream of the emulsion zone 21. The roller 251 which guides the heat-adhesive adhesive film 3 upstream of the heater 24 is provided. The heat-adhesive adhesive film 3 is laminated on the upper surface of the glass fiber 20. When heated by the ultraviolet intensifier 24, the adhesive film 3 is melted, and the melted adhesive film 3 and the glass fiber sheet 20 are pressed together by a roller 252. The laminated sheet thus produced is cut to a desired size using a cutter 26 moving vertically at regular intervals.

The laminated sheet was manufactured using the apparatus mentioned above. In the glass fiber sheet 20, what was produced as follows was used. First, a web was formed by mixing E parts of glass (E glass; diameter of 9 μm, fiber length of 50 to 80 mm) and 10 parts by weight of polyester fiber (3 denier, fiber length of 50 to 80 mm). The web was then needle punched using a 19th felt needle (needle tread density 20 points / cm 2, needle penetration length 14 mm) to make a sheet 6 mm thick and weighing 550 g / cm 2. The emulsion zone 21a was prepared by the following method. First, 100 parts by weight of polystyrene resin emulsion (ULTRASOL, Takeda Chemical Co., Ltd .; solid content 50%), 20 parts by weight of acrylic resin emulsion (ULTRASOL, Takeda Chemical Co., Ltd .; solid content 50%) (nitrile butadiene) 20 parts by weight of rubber (CROSLENE, Takeda Chemical Co., Ltd.) and 10 parts by weight of effervescent microbead (Microsphere; 70% of solid content of 70%, maximum foaming ratio of 70) are mixed, and an appropriate amount of viscosity improving agent is added to the mixture. And water were added to obtain an emulsion having a solid content of 30%.

The glass fiber sheet 20 manufactured in the continuous form as described above is impregnated with the emulsion zone 21a, and thus, the absorption of the emulsion zone 21a in the glass fiber sheet 20 through the rollers 223 is solid. It was adjusted to about 350 g / m ^{2 in the} form of material. The sheet 20 was then dried in a hot air dryer 23 at about 100 ° C. In this drying process, the glass fibers of the glass fiber sheet 20 were partially bonded by a thermoplastic resin binder. Next, the adhesive film 3 was laminated on the surface of the glass fiber sheet thus dried and containing the emulsion component by passing between the rollers 251. As the adhesive film 3, a polyamide-based heat sealable adhesive (melting temperature about 120 ° C. and a weight of 50 g / m ² ) was used. The adhesive film 3 was heated and softened by an infrared heater 24 and then pressed onto a glass fiber sheet by rollers 253. The sheet thus laminated was cut by a cutter 26 to obtain a laminated plate 4 composed of a glass fiber sheet (ie, a support layer) 2 and an adhesive film 3 containing an emulsion component. 3 shows a cross-sectional view of the laminate 4. The laminate 4 is about 4.0 mm thick and weighs 950 g / m ² .

Next, the laminated board 4 is moved into the heating furnaces 27 and 27 'provided with the some heater 270 or 271' shown in FIG. 4, respectively, and is heated at 170 degreeC. The press molding tools 28 and 28 'shown in FIG. 5 are provided. The surface material 5 was superimposed on the laminated board 4 so that the layer of the adhesive film 3 of the heated laminated board 4 contacted with the surface material, and was clamp press-molded by the press molding tools 28 and 28 '. As a surface material, the sheet supported by the urethane foam sheet was used. The urethane foam sheet has a foaming rate of 30 and a thickness of 3.0 mm. The clamping pressure was 0.5 to 2.0 kg / cm 2, the mold temperature was 60 ° C., and the mold gap was 6.0 mm and press molded for 30 seconds.

6 is a perspective view of the automotive interior material 1 formed by processing after molding.

A cross-sectional view of the interior material 1 molded in this manner is shown in FIG. The interior material 1 has a support layer 2 containing foamed microbeads, a heat sealable adhesive film 3 provided on the support layer 2, and a surface material 5 provided on the adhesive film 3. The glass fibers 2a are partially bonded to the binder 2b and the foamed microbeads 2c are distributed almost uniformly in the entire support layer.

Table 1 shows the types and amounts of glass fibers, emulsions, and heat-adhesive adhesives used in the manufacture of interior materials, the weight, thickness, and apparent density of the laminate 4, and the physical properties of the support layers of the molded interior materials.

The bending strength shown in Table 1 was measured by the following method. The test piece was hung on a support 100 mm apart, a pressure was applied to the center of the test piece in the thickness direction thereof, and the pressure immediately before cutting of the test piece was recorded as the bending strength. Moldability (i.e., properties that follow the mold shape) refers to the ability to retain the internal shape of the mold as it is, leaving no gaps, in particular the bend in the mold. ? Indicates that excellent molding having a uniform thickness was obtained over all surfaces of the mold and including complex bent portions, while? Indicates that a gap was formed in the mold resulting in an uneven molding state.

In the adhesiveness of a surface material, a mark ((circle)) becomes the outstanding adhesiveness and shows that a urethane foam is not removed. When a force is applied to remove the urethane foam, it bursts. ? Indicates that the urethane foam is easily removed from the surface of the support layer, although apparent adhesion has occurred. The sound absorption properties (normal incidence absorption) were measured by the method of Japanese Industrial Standard JIS A1405. The higher the value, the better the absorbency.

Comparative example

Without using the expandable microbeads, the weight of the emulsion zone was used as shown in Table 1, and was carried out in the same manner as in the above-described example, except that the gap of the mold was set to 4.0 mm.

TABLE 1

As compared with the interior material obtained by the present invention and the interior material of the comparative example, it can be seen from Table 1 that the interior material according to the present invention is excellent in terms of bending strength, adhesion to a moldable surface material, and sound absorption properties.

Those skilled in the art will be able to facilitate various other changes without departing from the spirit and scope of the invention. Thus, the scope of the claims appended hereto is not limited to those described herein, but rather can be treated as equivalents to the consumer by common knowledge from this invention, including all of the patentable novelty features inherent in the invention. It should be understood to include all features that are present comprehensively.

Claims (9)

A support layer comprising a needled glass fiber sheet containing a thermoplastic resin binder, the needled glass fiber mainly consisting of glass fibers; An air permeable heat sealable adhesive layer provided on the support layer; And an air permeable surface layer installed on the adhesive layer, wherein the support layer further contains foamed microbeads. The interior material according to claim 1, wherein the blowing agent microbeads are formed by heat-treating the expandable microbeads. The interior material according to claim 2, wherein the expandable microbead is a thermoplastic resin particle containing a blowing agent. 3. The thermoplastic resin binder according to claim 2, wherein the thermoplastic resin binder is contained in an amount of 20 to 80 parts by weight per 100 parts by weight of the glass fiber sheet, and the phase binder expandable microbead is in an amount of 2 to 50 parts by weight per 100 parts by weight of the thermoplastic resin binder. Interior material characterized in that it contains. The interior material of claim 1 wherein the needled glass fiber sheet further contains organic fibers. Providing a needled glass fiber sheet composed mainly of glass fiber; Dispersing a thermoplastic resin binder and expandable microbeads in the needled glass fiber sheet to form a support layer; Forming an air permeable heat sealable adhesive layer on the surface of the support layer, heating the obtained bilayer laminate to expand the expandable microbeads and to melt the heat sealable adhesive; A method of manufacturing a vehicle interior comprising a step of loading an air permeable surface material on the surface of the adhesive layer and cold compression molding the obtained three-layer laminate. The method according to claim 6, wherein the expandable microbead is a thermoplastic resin particle containing a blowing agent. The method according to claim 6, wherein the thermoplastic resin binder is contained in an amount of 20 to 80 parts by weight per 100 parts by weight of the glass fiber sheet, and the expandable microbead is contained in an amount of 2 to 50 parts by weight per 100 parts by weight of the thermoplastic resin binder. Manufacturing method characterized in that. 7. A method according to claim 6, wherein said needled glass fiber sheet further contains organic fibers.

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