JPH0732328A - Hot press molding mat and its manufacture - Google Patents

Abstract

PURPOSE:To eliminate troubles in a fabricating process for heat press molding mat consisting of a fibrous material which is used as a core material of an interior automotive trim by hot press molding fabrication. CONSTITUTION:Thermosetting resin 5 and, if necessary, inorganic fiber and thermoplastic resin 6 are uniformly mixed in natural fiber 2 and synthetic fiber 3 to form a hot press molding mat 7. Then, both surfaces or at least one side surface of the hot press molding mat 7 are heated before hot press molding, and covered with a semi-hardened state resin layer 9 before hot press molding. Since the resin layer 9 consisting of synthetic resin or the like is formed thus on the surface of the hot press molding mat, dust is prevented from being generated in carrying and a hot press molding process. Further since tensile strength is improved with the resin layer 9, the hot press molding mat is excellent in handling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermocompression molding mat composed of a fibrous material which is used as a core material for automobile interior materials after being subjected to a flat-plate or deep-drawing thermocompression molding, and a method for producing the mat. More specifically, the present invention relates to a mat for thermocompression molding that prevents dust during handling and prevents defective products with a surface finish that adheres a skin material, and a method for manufacturing the mat.

[0002]

2. Description of the Related Art When producing a mat for thermocompression molding of this kind, a thermoplastic resin is appropriately mixed with wood fiber, hemp or other natural fiber, and further, if necessary, glass fiber, rock wool or other inorganic fiber. Fibers and a thermoplastic resin are mixed and the mixture is molded into a bulky mat with a mat molding machine. afterwards,
In order to impart handling aptitude, hot air ventilation treatment is used to slightly melt and bond the resin component (oven method),
Alternatively, the fibers were physically entangled with a needle punch machine (needle method).

[0003]

However, the thermocompression molding mat produced in this way is a fine matte fiber in the mat and a product after thermocompression molding during handling until the molding process in the conveying or thermocompression molding process. The thermosetting resin such as powdered phenolic resin, which is added to improve the physical properties of the above, is a material that is liable to fall off and scatter, which is so-called dust.

Particularly, in the case of the material obtained by the needle method, these fine fibers and powdery thermosetting resin are only physically incorporated into the mat and have a chemical adhesive force. Since it does not exist, it falls off from the mat significantly during handling.

Further, if necessary, reinforcement of the molded product,
In particular, inorganic fibers such as glass fibers may be added for the purpose of preventing deformation due to moisture absorption.
Since it is very fine, around 0μ, and it is easy to break, it falls off and scatters during handling.

By the way, these powdered phenolic resins and other thermosetting resins and inorganic fibers may cause itching and rashes when attached to the skin of an operator.

[0007] Further, these scattered dust not only worsens the working environment, but, for example, in the case where a thin decorative sheet or the like is attached for decoration in the same building, these dusts are molded products. And the surface material such as a decorative sheet may be present, and the quality of the decorated product may be deteriorated.

[0008] Moreover, the so-called shea in which the defibration of the wood fiber is insufficient
Rough woody materials called ve are likely to be generated, and this
The sheave falls onto the mold surface, and it remains attached to the mold surface as it is, creating recesses on the surface of the thermocompression molded product. It may cause a defect.

In view of the above circumstances, the present invention prevents the generation of dust due to the falling and scattering of fine fibers and powdery resin, and the sheave, which is a surface defect of a molded product, during handling, and handles the mat. An object of the present invention is to provide a thermocompression molding mat capable of increasing strength and a method for producing the mat.

[0010]

The invention of the mat for thermocompression molding of the present invention includes a natural fiber (2), a synthetic fiber (3), a thermosetting resin (5) and, if necessary, an inorganic fiber and a thermosetting resin. In a thermocompression molding mat (7) obtained by mixing with a plastic resin (6), both or at least one surface of the thermocompression molding mat is coated with a semi-cured resin layer (9) before thermocompression molding. It is composed by coating.

On the other hand, in the invention of the method for producing a mat for thermocompression molding of the present invention, the thermosetting resin (5) and optionally the inorganic fiber and the thermoplastic fiber are added to the natural fiber (2) and synthetic fiber (3). The resin (6) is uniformly mixed to form a thermocompression molding mat (7), and both or at least one surface of the thermocompression molding mat is heated before thermocompression molding so that the heating surface is heated. It is configured to be covered with a semi-cured resin layer (9) before pressure molding.

Further, a resin solution (11) of a thermosetting resin or a thermoplastic resin is applied to the thermocompression molding mat (7), which is dried to form a semi-cured resin layer before thermocompression molding ( 9) to be covered.

[0013]

With the above-mentioned constitution, according to the present invention, the resin layer (9) on the surface of the thermocompression molding mat (7) suppresses the generation of dust, and when the skin material is adhered, a sheave of a surface becomes a defect. It acts to prevent falling and to contribute to the improvement of tensile strength.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a thermocompression molding mat according to the present invention, and FIG. 2 is a front view showing an example of a process for producing a thermocompression molding mat by an oven method using a heat roll. FIG. 3 is a front view showing an example of a process for producing a thermocompression molding mat by a needle method using a heat roll, and FIG. 4 is an example of a process for producing a thermocompression molding mat by an oven method using a spray nozzle. The front view shown in FIG. 5, FIG. 5 is a front view showing an example of a process for producing a thermocompression molding mat by a needle method using a spray nozzle, FIG. 6 is a graph showing the relationship between the processing temperature and the amount of dust generation, and FIG. It is a graph which shows the influence which a processing temperature has on the physical property of a mat, (a) is a graph which shows the relationship between a processing temperature and the tensile strength of a mat,
(B) is a graph showing the relationship between the processing temperature and the bulk density of the mat, FIG. 8 is a graph showing the relationship between the resin coating amount and the dust generation amount, and FIG. 9 is a graph showing the influence of the resin coating amount on the bending strength. And (a) is a graph for single-sided coating,
(B) is a graph in the case of double-sided coating.

As shown in FIG. 1, the thermocompression molding mat of the present invention comprises wood fibers, hemp and other natural fibers 2 obtained by steaming and disintegrating wood chips, and chemically synthesized fibers 3 such as polyester.
And a thermosetting resin 5 such as a phenol resin, and if necessary, an inorganic fiber such as glass fiber or a thermoplastic resin 6 such as a polyethylene resin and the like are uniformly mixed, and the resulting mixture is bulked by a mat molding machine. A bulk specific gravity of 0.05 to 0.1 g / cm ³ and a basis weight of 1.0 to 3.0 kg / m ² which are generally used for molding core materials for interior materials such as so-called automobile doors which are molded into a mat shape. A mat which is bulky to some extent and which is passed through between a pair of upper and lower rolls or steel belts in which both or at least one of them has been heated and subjected to heat compression treatment, or heat applied to both or at least one surface of the mat. By applying a resin solution such as a curable resin or a thermoplastic resin, and then heating and drying the solution, both or at least one surface of the mat is a semi-cured resin layer before thermocompression molding. In is intended to cover. Here, the semi-cured state is a state in which it is cured to the extent that handling is not a problem.

As the natural fiber 2 of the above fiber materials, wood chips such as softwood and hardwood, which are generally used as raw materials for wood fiberboard, are defibrated by a conventional method and dried to a water content of about 25% or less. The wood fibers are mainly used, and if necessary, hemp, cotton or other fibers having a long fiber length may be mixed.

As the synthetic fiber 3, polyester, nylon or the like is used. In addition, this synthetic fiber 3
May be fluffy fibers including cotton or synthetic fibers for cost reduction.

Furthermore, if necessary, these natural fibers 2,
In addition to the synthetic fibers 3, inorganic fibers such as glass fibers may be added in order to reinforce the thermoformed product and improve the moisture resistance.

On the other hand, examples of the thermosetting resin 5 include phenol resin and melamine resin. Further, in the production of the thermocompression molding mat 7, in the oven method in which hot air treatment is performed to slightly melt and bond the resin component in order to impart handling suitability to the mat, the thermoplastic resin 6 is added as the resin to be melt bonded. . Examples of the thermoplastic resin 6 include polyethylene resin and polypropylene resin. Incidentally, these resins are added in the form of powder, liquid or the like (in the case of a thermoplastic resin, it may be fibrous).

Next, a method for manufacturing the thermocompression molding mat will be described in detail.

The thermocompression molding mat according to the present invention is obtained by coating both or at least one surface of the mat with a semi-cured resin layer 9 before thermocompression molding. This resin layer 9 is shown in FIGS. As shown, after passing the mat 7 between the heat rolls 10 (or heat steel belt), it is conveyed into the oven 12, or, as shown in FIGS. 4 and 5,
A resin solution 11 such as a thermosetting resin or a thermoplastic resin is applied to both or at least one surface of the mat 7,
After that, it is manufactured by drying in the oven 12 (note that the thickness regulating roll 13 is to the right of the oven 12).
Is provided. ).

The heating and compressing treatment for passing the thermocompression molding mat 7 between the hot rolls 10 or the hot steel belts is carried out when the manufacturing method of the thermocompression molding mat 7 is an oven method (see FIG. 2). It may be before or after the mat 7 is dried in the oven 12. Further, in the case of the needle construction method (see FIG. 3), it is preferable to perform the needle treatment.

On the other hand, the treatment temperature at that time is preferably 150 to 200 ° C., though it depends on the resins used. That is, as shown in FIGS. 6 and 7, the relationship between the treatment temperature and the amount of dust generated, the bulk density of the mat, and the tensile strength of the mat is as shown in FIGS. The amount is small and the handling (tensile strength) is also good. On the other hand, since the bulk density of the mat becomes high, the flexibility of the mat becomes poor and the mat does not fit well in deep drawing, and when the processing temperature is 230 ° C. or higher, the entire mat becomes hot roll 10 or heat. Since problems such as adhesion to the steel belt occur, it is preferable that the temperature is around 200 ° C. On the other hand, if the temperature is 100 ° C. or lower, the resin layer is not sufficiently molded and the effect of reducing the amount of dust is small. There is a problem of fine adhesion,
From this point, a temperature of 150 ° C. or higher is desirable.

The formation of the resin layer 9 depends on that the added thermosetting resin 5 is partially cured. However, the resin such as hemicellulose and lignin contained in the wood fiber is present in the presence of water. It is considered that the resin layer 9 is instantly formed by being plasticized by heat. Therefore, the water content of wood fiber is
At least 2% or more is necessary for the plasticization of hemicellulose, lignin and the like. Below this, the resin layer 9 is less formed on the surface of the mat, so that the effect of reducing the amount of dust generated is small. On the other hand, the higher the water content, the lower the temperature at which hemicellulose and lignin soften, so the temperature of the heat treatment can be lowered, but as described above, the fibers of the thermocompression molding mat 7 are From the point of adhesion, a temperature of at least 150 ° C is required, at which temperature hemicellulose or lignin can be softened to form a resin layer, and from the viewpoint of moldability of the subsequent thermocompression molding, the water content is around 30%. Is preferred.

The interval between the hot rolls 10 or the hot steel belt may be appropriately determined depending on the thickness of the hot-pressing mat 7 before processing. That is, there is no particular limitation as long as the distance is such that the mat 7 can pass through.

Further, since the mat 7 is heated and compressed, the thickness thereof is reduced by about 10 to 40% as compared with that before the treatment, so that a large number of sheets can be piled up in the case of depositing and storing, and space saving can be achieved. And so on. On the other hand, regarding the thermocompression moldability of the mat 7, the flexibility of the mat 7 is somewhat deteriorated as the thickness of the mat 7 is reduced, but the resin layer formed on the surface improves the tensile strength of the mat 7 (see FIG. 7), even in deep drawing, if the temperature is within the above-mentioned processing temperature range, molding can be carried out without causing mat breakage, and there is no particular problem.

Next, a resin solution 11 such as a thermosetting resin or a thermoplastic resin is applied to the surface of the thermocompression molding mat,
Then, a manufacturing method of drying the resin layer 9 to form the resin layer 9 will be described.

To apply the resin solution 11 such as thermosetting resin or thermoplastic resin to the surface of the thermocompression molding mat 7, the molding method of the thermocompression molding mat 7 is an oven method (see FIG. 4).
In the reference), it is performed before passing through the oven 12, and then dried in the oven 12 to form the resin layer 9. On the other hand, in the needle construction method (see FIG. 5), the resin solution 11 may be applied after the needle punch processing by the needle punch machine 16 and then dried in the oven 12 to form the resin layer 9.

Here, these resin solutions 11 may be either thermoplastic or thermosetting resin solutions for the purpose of only preventing dust, but in the case of also aiming to reinforce the molded body after thermocompression molding. Is preferably a thermosetting resin. The thermosetting resin may be an emulsion type phenol resin. On the other hand, examples of the thermoplastic resin include emulsion type acrylic resin and vinyl acetate resin.

Further, as shown in FIG. 8, the coating amount of the resin solution 11 is at least 5 g / m ² from the viewpoint of preventing dust.
(Solid component conversion) or more is required. Furthermore, this resin layer 9
The effect becomes more remarkable when the molding treatment is applied to both sides of the mat. For example, in the case where 5 g / m ^{2 is} applied to both the front and back sides, the amount of dust generated can be suppressed to 1/2 or less as compared with the case of no treatment.

On the other hand, the application of the resin solution 11 to form the resin layer 9 on the surface can improve the physical properties of the thermocompression molded product. For example, a lightweight product such as a ceiling material usually has a specific gravity of 0. A strength of about 200 kg / cm ² or more is required at about 5 to 0.7, but only 130 to 140 kg / cm ² with a specific gravity of 0.5 can be obtained with a molded article made of untreated mat.
On the other hand, one coated on one side at 40 g / m ² (converted to solid content) can obtain a strength of about 250 kg / cm ² ,
If it is applied at 40 g / m ² (converted to the solid content), the required strength as a molded product can be obtained (see FIG. 9 (a)). In addition, since the strength of about 200 kg / cm ² can be obtained by applying 12 g / m ² (converted to solid content) on both sides, 12 g / m ^2
2 (Converted to solid content) If applied, the required strength as a molded product can be obtained (see FIG. 9 (b)).

As described above, one side is 5 g / m in terms of dust prevention.
² may be (solid content) or coating, but economics and in terms of reinforcing effect of the molded article after thermal molding, about 40 g / m ² on one surface coating as the upper limit, 12 g / m ² approximately by double-side coating Is preferred.

The concentration of the resin solution 11 is preferably about 5-40%. If the concentration is less than 5%, it is necessary to increase the coating amount, and the drying in the resin layer molding process becomes long.
Further, it becomes easy to penetrate into the inside of the mat, and a large amount of resin is required. On the other hand, if the concentration becomes higher than 40%,
The amount of coating becomes small, and it is difficult to apply this uniformly, and there are problems such as uneven coating.

The resin solution 11 may be applied by a commonly used spray method. Although the single-sided coating method is illustrated in FIGS. 4 and 5, when performing double-sided coating, the mat may be reversed and flowed again, or the conveyor 15 may be cut halfway and coated from both sides of the mat at the same time.

[0036]

As described above, since the resin layer made of synthetic resin or the like is formed on the surface of the thermocompression molding mat, it is added as fine wood fiber, inorganic fiber or reinforcing agent. It is possible to prevent a situation in which a thermosetting resin or the like such as a powdery phenol resin falls off from the thermocompression molding mat during transportation or handling during thermocompression molding and is scattered.

Further, the resin layer improves the tensile strength of the thermocompression molding mat, resulting in excellent handling properties.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a thermocompression molding mat of the present invention.

FIG. 2 is a front view showing an example of a process for producing a thermocompression molding mat by an oven method using a hot roll.

FIG. 3 is a front view showing an example of a process for producing a thermocompression molding mat by a needle method using a hot roll.

FIG. 4 is a front view showing an example of a process of manufacturing a thermocompression molding mat by an oven method using a spray nozzle.

FIG. 5 is a front view showing an example of a process of manufacturing a thermocompression molding mat by a needle method using a spray nozzle.

FIG. 6 is a graph showing the relationship between the processing temperature and the amount of dust generated.

FIG. 7 is a graph showing the influence of the treatment temperature on the physical properties of the mat, (a) showing the relation between the treatment temperature and the tensile strength of the mat, and (b) showing the treatment temperature and the bulk density of the mat. It is a graph which shows the relationship with.

FIG. 8 is a graph showing a relationship between a resin coating amount and a dust generation amount.

9A and 9B are graphs showing the influence of the resin coating amount on the bending strength, where FIG. 9A is a graph for single-sided coating, and FIG. 9B is a graph for double-sided coating.

[Explanation of symbols]

 2 ... Natural fiber 3 ... Synthetic fiber 5 ... Thermosetting resin 6 ... Thermoplastic resin 7 ... Thermoforming mat 9 ... Resin layer 11 ... Resin solution

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Namba 3-8-4 Nihonbashihonmachi, Chuo-ku, Tokyo Mitsui Wood Industry Co., Ltd.

Claims (3)

[Claims] 1. A thermocompression molding mat formed by mixing a natural fiber and a synthetic fiber with a thermosetting resin, and optionally an inorganic fiber and a thermoplastic resin. At least one or both of the thermocompression molding mat. A mat for thermocompression molding, which is formed by coating the surface of the resin with a semi-cured resin layer before thermocompression molding. 2. Natural and synthetic fibers are uniformly mixed with a thermosetting resin and, if necessary, an inorganic fiber and a thermoplastic resin to form a thermocompression molding mat, and both of the thermocompression molding mats are formed. Alternatively, a method for producing a thermocompression molding mat, in which at least one surface is heated before thermocompression molding so that the heating surface is covered with a semi-cured resin layer before thermocompression molding. 3. A structure in which a thermosetting resin or a resin solution of a thermoplastic resin is applied to a thermocompression molding mat, which is dried and covered with a semi-cured resin layer before thermocompression molding. For producing a mat for thermocompression molding.