JP2003103551A - Molded object constituted of woody fiber material and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber laminate not increased in weight and having good bending rigidity. SOLUTION: The method for molding the molded object containing a woody fiber material and a binder includes a process for supplying the foamable binder to the gap between at least two mat-like members formed of the woody fiber material and a process for press-molding the mat-like members obtained in the process in a laminated state and foaming and curing the foamable binder. In this manufacturing method, the foamable binder supplied to the gap between the mat-like members is foamed at the time of press molding and penetrates into the interstices of the woody fiber material of the mat-like members by the gas pressure of the foamable binder to bond the woody fiber material. At the same time, the foamable binder well holds foamed gas between the mat-like members to form a foamed structure. Therefore, the molded object 100 having a low density layered part 101 low in the content of the woody fiber material between layered parts 102 and 103 of high rigidity increased in the content of the woody fiber material can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded product made of a wood fiber material.

[0002]

2. Description of the Related Art Conventionally, there has been known a technique for producing a so-called hard board, which is a molded article made of a fiber material used as an interior material of an automobile (a base material for a door trim etc.). In this technique, first, a wood-based fiber material is defibrated and then entangled by needle punching or the like to form a fiber mat. Next, a liquid urethane raw material is applied to this fiber mat as a binder and hot pressed to foam and cure the urethane raw material, and at the same time, to form a laminated molded article.

By the way, such a molded product may be required to have high rigidity and light weight. In particular, it is preferable that the molded product used as the base material for automobile trim has high bending rigidity and is lightweight. The rigidity of the wood-based fiber material is achieved by increasing the weight of the wood-based fiber material per unit area. Further, the improvement of bending rigidity can be achieved by increasing the thickness of the molded product. However, if the weight per unit area of the wood fiber material is increased and the thickness thereof is increased, the molded product becomes heavy.

[0004]

Therefore, according to the present invention,
An object of the present invention is to provide a method for manufacturing a molded body that is made of a wood-based fiber material and that has good bending rigidity while suppressing weighting. Another object of the present invention is to provide a molded product which is not made heavy and is made of a wood fiber material having good bending rigidity.

[0005]

In order to solve the above problems, the present invention provides a method for producing a molded article containing a wood fiber material and a binder, which comprises at least two wood fiber materials. A step of supplying a foamable binder between the mat-shaped members; and a step of press-molding the laminated mat-shaped member obtained in the above step, and foaming and curing the foamable binder, A manufacturing method is provided. In this manufacturing method, the foamable binder is supplied between the mat-like members adjacent to each other during lamination, foams during press molding, and penetrates between the wood-based fiber materials of the mat-like members due to the gas pressure thereof. , Hardens to bond wood fiber materials. As a result, the wood-based fiber material is densely present, and a layered portion having the wood-based fiber material as a main constituent component in which the fibers are bonded by the binder is formed. Also,
The foamable binder that foams when sandwiched between two mat-shaped members can hold gas well and is well foamed and molded. As a result, a layered portion having a high binder content and a low specific gravity is formed between the mat-shaped members. Therefore, according to the present manufacturing method, it is possible to obtain a molded product having a low density layered portion having a small content rate of the wood-based fiber material between the layered portions containing fibers having high rigidity as a main constituent. That is, in the present manufacturing method, it is possible to increase the thickness of the molded product without increasing the amount of the wood-based fiber material used, and it is possible to manufacture a molded product that suppresses weighting and has good bending rigidity. .

In the present specification, "between mat-shaped members" means between the surfaces, including the surfaces of the two mat-shaped members facing each other. Therefore, the foamable binder is
For example, it can be supplied between the mat-shaped members by providing it on the surface of the mat-shaped member or by impregnating the surface of the mat-shaped member.

Further, in the above method for producing a molded article, when the foamable binder is a urethane raw material, it is possible to satisfactorily bond the wood-based fiber material and foam at a portion having a large binder content. The magnification can be increased. The urethane raw material is 2 with respect to the total weight of the mat-shaped member.
When the content is 0% by weight or more and 40% by weight or less, the weight of the binder is reduced, the wood-based fiber material is satisfactorily bound, and a portion having a high binder content can be molded.

Further, according to the present invention, in a molded product containing a wood fiber material and a binder, the content ratio of the wood fiber material decreases from one side to the other side in the thickness direction of the molded product. Then, the molded body is provided with a portion having a gradient composition in which the content ratio of the binder increases from the one side to the other side in the thickness direction of the molded body. Further, in a molded product containing a wood-based fiber material and a binder, the content rate of the wood-based fiber material is increased in one surface layer side and the other surface layer side of the molded product and decreased in the central portion, The molded article has a graded composition in which the content of is reduced on the one surface layer side and the other surface layer side and is increased in the central portion. Further, at least a part of the binder provides a molded body having a foamed structure. In these moldings, the density of the wood-based fiber material is high in the portion where the content of the wood-based fiber material is increased and the content of the binder is decreased, and the rigidity is secured mainly by the wood-based fiber material. On the other hand, in the portion where the content rate of the wood fiber material is decreased and the content rate of the binder is increased, the thickness and rigidity are secured by the binder even if the wood fiber material is small. Therefore, even if the content of the wood-based fiber material is small, a region having rigidity is secured. In particular, when a portion having a large content of the wood fiber material and a small content of the binder is provided on both surface layers, the rigidity of the outer side of the molded body is high, and good bending rigidity can be secured. Also,
When the binder has a foamed structure in these molded products, it is preferable because the molded product has a thickness while the weight of the binder is reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, a case where a molded body suitable for being used as a trim base material of an automobile is manufactured will be described as an example. The manufacturing method of the present embodiment includes a step of forming a plurality of mat-shaped members from a wood-based fiber material, a step of supplying an expandable binder between at least two mat-shaped members, and pressing the mat-shaped members in a laminated state. Molding and foaming and curing the expandable binder.

(Manufacture of mat-like member made of wood fiber material) The wood fiber material used in this manufacturing method is a non-woven fabric such as kenaf, palm, palm, sisal, Manila hemp, kozo, hemp, straw or bagasse. Various fibers obtained from wood-based raw materials and wood-based raw materials such as hardwoods and conifers can be used. The wood fiber material may be mechanical pulp, chemical pulp, semi-chemical pulp, recycled pulp thereof, or various artificial cellulose fibers synthesized from these pulps. The wood-based fiber material is a combination of one or more of the above fibers. As the fiber material, fibers having various fiber lengths can be used, but by using a fiber material having a relatively long fiber length, elasticity can be imparted to the fiber layer. Preferably, a fiber obtained from kenaf can be used as the wood fiber material.

The wood fiber material can be subdivided into fibers by defibration. The defibration method is not particularly limited and may be a wet method or a dry method. Further, after steaming, it is also possible to use a material disintegrated by blasting to release the pressure during steaming at once. The wood fiber material is formed into a mat-shaped member. The mat-shaped member can be formed by intertwining the wood-based fiber materials in various ways and fixing them. For example, the mat-shaped member can be formed by needle-punching the laminated fiber materials with a fiber material having a long fiber length. In this embodiment, the carded fiber material is inflated by air injection (air lay),
The mat-shaped members 12 and 13 shown in FIG. 1 were formed by fleece so that each fiber material was entangled. The mat-shaped members 12 and 13 are formed to have a thickness of 5 to 7.5 mm or more.

The mat-like members 12 and 13 may be made of different materials and have different properties and have different properties. From the viewpoint of bending rigidity of the manufactured molded body 100, it is preferable that various physical properties, particularly rigidity, are symmetrical in the thickness direction of the molded body 100. Therefore, in the molded body 100 of the present embodiment, the mat-shaped member 1
2 and 13 are made of the same material, and as shown in FIG. 1, are made to have the same thickness.
The mat-shaped members 12 and 13 may additionally contain thermoplastic resin fibers. The thermoplastic resin fibers can be mixed into the wood-based fiber material in a state of being mixed in the wood-based fiber material and entangled in the same manner as the wood-based fiber material.

(Supply of expandable binder) Next, the expandable binder is supplied between at least two mat-like members. The binder can be selected from various binders that can bond wood fiber materials and can be foam-molded. For example, it can be used as an olefinic thermoplastic resin such as polyethylene or polypropylene, or a polyester thermoplastic resin such as polyethylene terephthalate or its raw material and a crosslinking agent, or a urethane resin raw material. It is preferably selected from urethane resin raw materials and raw materials such as olefinic thermoplastic resins. Further, the foamable binder preferably has fluidity when heated. Such a foamable binder can satisfactorily penetrate into the mat-like member during the binding reaction (foaming or curing reaction) to satisfactorily bind the wood-based fiber material.

The expandable binder can be supplied between the mat-like members in various forms. For example, the expandable binder is formed into a matte form in a solid state in various forms such as a film form, a plate form and a fibrous form. It can be supplied by arranging it on the surface of the member. Also,
By preparing the foamable binder in a fluid state such as a liquid, the foamable binder can be directly provided on the surface of the mat-like member in the form of a film and supplied between the mat-like members. As the method of providing the foamable binder in a film form, various known methods such as a method of spraying or coating the surface of the mat-shaped member and a method of immersing the surface of the mat-shaped member in a bath of the binder are selected. be able to.

The foamable binder may be impregnated into the surface of the mat-like member, but it is preferably provided in the form of a film on the surface of the mat-like member, and more preferably, a film is formed on the surface of the mat-like member. It is provided to do. In this form,
Since the binder is reliably held between the mat-shaped members, it is easy to form a portion having a large content of the binder between the portions having a large content of the wood fiber material. When the foamable binder is provided in the form of a film, the foamable binder may be provided on at least one of the two surfaces of the two mat-shaped members facing each other. The binder can be supplied to the surface of the mat-shaped member that constitutes the outside of the molded body 100, but from the viewpoint of ensuring surface rigidity, the binder is supplied to the surface formed on the outside surface of the molded body 100. do not do.

In this embodiment, the mat-shaped members 12 and 13 are
Liquid-prepared urethane raw materials were sprayed on the surfaces opposed to each other during the lamination, and a film-like expandable binder 11 was provided on the surfaces of the mat-like members 12 and 13, as shown in FIG.

Here, the urethane raw material (11) supplied
Is preferably 20 parts by weight or more and 40 parts by weight or less when the total weight of the mat-shaped members 12 and 13 is 100 parts by weight. If the amount is less than 20 parts by weight, the wood-based fiber material cannot be sufficiently bonded, or the thickness of the bonding layer 101 becomes small, and preferable suppression of weight reduction and improvement of bending rigidity may not be performed. On the other hand, when it exceeds 40 parts by weight, the weight of the binder itself causes the molded body 100 to become heavy, and the product cost (cost of the binder) increases. Further, it is preferable that the urethane raw material is more uniformly provided to the mat-shaped members 12 and 13, and 10 parts by weight or more and 20 parts by weight or less of each of the mat-shaped members 12 and 13 is preferably supplied. In this embodiment, the sum of the weights of the mat-shaped members 12 and 13 is 100 parts by weight, and one surface of the mat-shaped members 12 and 13 is made of urethane raw material.
0 parts by weight was supplied, and 20 parts by weight of the urethane raw material was supplied as a whole.

(Press Molding and Foaming and Curing of Binder) After that, the mat-shaped members 12 and 13 are arranged in a laminate and press molded, and the foamable binder 11 is foamed and cured. The press molding can be performed in various known forms, and is performed at a temperature equal to or higher than the foaming temperature and the curing temperature of the expandable binder 11.

In press molding, the mat-shaped members 12, 13
Is compressed into a predetermined thickness. Effervescent binder 11
When foamed, it penetrates into the wood-based fiber material under gas pressure. Then, the invading binder is hardened to bond the wood-based fiber materials together. At the same time, the expandable binder 11 expands and hardens between the mat-shaped members 12 and 13 formed by foaming against the pressure applied by press molding. In this way, the fiber layers 102 and 103 in which the content rate of the wood fiber material is increased are formed, and at the same time, the fiber layer 10 is formed.
2, the bonding layer 101 in which the content of the binder is increased is formed. In the present embodiment, each is 5
Two mat-shaped members 12, 1 having a thickness of 7.5 mm
3 can be press-molded to obtain a molded body 100 having a thickness of 2.3 mm shown in FIG.

Next, a molded body 100 according to an embodiment of the present invention obtained by the above manufacturing method will be described with reference to FIG. The molded body 100 includes the fiber layer 10
2, the bonding layer 101, the fiber layer 103 is provided in this order, the content rate of the wood-based fiber material decreases from one side in the thickness direction of the molded body toward the other side, the content rate of the binder, A portion having a gradient composition that increases from the one side to the other side in the thickness direction of the molded body is provided.

The fiber layers 102 and 103 are made of a wood-based fiber material which is entangled with each other.
It is bound by a binder. Fiber layers 102, 103
In, the wood-based fiber material has a high content rate and is formed with a high density, and the wood-based fiber material increases the rigidity. In this embodiment, the fiber layers 102 and 103 have the highest content rate of the wood fiber material on both outer sides of the molded body 100, and the content rate decreases toward the bonding layer 101 side. In, the content of binder is increased. Further, the bonding layer 101 side may be formed in a porous shape. If the content rate of the wood fiber material is symmetrical in the thickness direction of the molded body 100, the rigidity imparted by the wood fiber material becomes symmetrical in the thickness direction of the molded body 100, and the rigidity of the molded body 100 and It is preferable because the bending rigidity becomes good.

The binding layer 101 is a portion where the content of the binder is increased as compared with the fiber layers 102 and 103.
The bonding layer 101 of the present embodiment does not have a clear boundary between the fiber layers 102 and 103, and contains a wood fiber material. The bonding layer 101 may have a wood-based fiber material as a main constituent. Further, the content rate of the wood-based fiber material in the bonding layer 101 may be increased toward the fiber layers 102 and 103. The bonding layer 101 preferably has a foamed structure. The foamed structure may be in a mixed state, regardless of whether it has a closed cell shape or an open cell shape. The binding layer 101 preferably has a small specific gravity within a range having a predetermined strength, and the binding layer 101 containing a urethane raw material has a good foaming structure and has a high strength, which is preferable. The preferable expansion ratio and weight ratio to the wood-based fiber material when the urethane raw material is used as the binder are the same as in the case of the above-described manufacturing method,
The description is omitted.

In the molded body 100, in the portion where rigidity is required, the content rate of the wood fiber material is increased and the weight of the wood fiber material per unit area is increased, so that the rigidity is not required so much. In, the content rate of the wood fiber material is reduced. Further, a portion where high rigidity is secured by the wood fiber material, that is, the molded body 100.
The content rate of the binder is reduced outside of, and the content of the binder in the molded body 100 is reduced. Therefore, the weight is efficiently reduced and the material cost is reduced. Particularly, in the molded body 100, the bonding layer 101 having a low specific gravity is provided between the fiber layers 102 and 103 having high rigidity to increase the thickness, and has a structure similar to a so-called sandwich structure. Therefore, the bending rigidity is favorably improved as compared with the weight of the wood-based fiber material used. In particular, since the bonding layer 101 has a foamed structure, the weight of the bonding layer 101 can be reduced as compared with the thickness of the bonding layer 101, and the weight of the molded body 100 is well suppressed.

According to the manufacturing method of this embodiment, the fiber layers 102 and 103 in which the content rate of the wood fiber material is increased.
The tie layer 101 with an increased binder content during
Is formed. For this reason, it is possible to manufacture a molded product which is made of the same material as that used in the case of manufacturing a fiber molded product using a urethane raw material as a binder and which suppresses weighting and has good bending rigidity.
In addition, since a new separate step for providing the bonding layer 101 is not particularly required, it is possible to manufacture a molded product having good bending rigidity while suppressing weighting by using a manufacturing apparatus similar to the conventional one.

The molded product according to the present invention is not limited to the above embodiment. The boundary between the fiber layer and the bonding layer may be clearly formed. The binding layer may contain no wood fiber material and may be composed of only a binder. Further, it has a binder layer mainly containing a binder and a fiber layer mainly containing a wood fiber material, between the binder layer and the fiber layer, between the wood fiber material and the foamable binder It may be configured such that another layer having a different mixing ratio is visually recognized. The transitional layer is, for example, a portion in which the gap between the respective fibrous materials is increased by foam molding and the binder has entered. Further, the molded product according to the present invention is not limited to the three-layer structure including two fiber layers, and it is needless to say that the molded product may include three or more fiber layers.

[0026]

EFFECTS OF THE INVENTION The present invention can provide a fiber molding which is not weighted and has good bending rigidity. Further, it is possible to provide a method for manufacturing a fiber molded body that suppresses weighting and has good bending rigidity.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mat-shaped member configured in a method for manufacturing a molded body according to the present invention.

FIG. 2 is a perspective view showing a state in which a foamable binder is provided on the mat-shaped member of FIG.

FIG. 3 is a cross-sectional view of a molded body manufactured by the manufacturing method of the present embodiment.

[Explanation of symbols]

100 molded body 102,103 fiber layers 101 Bonding layer 12,13 Mat-shaped member 11 Effervescent binder

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 9:00 B29L 9:00 31:58 31:58

Claims (6)

[Claims] 1. A method for producing a molded article containing a wood-based fiber material and a binder, the method comprising supplying an expandable binder between at least two mat-shaped members formed of the wood-based fiber material. A step of press-molding the laminated mat-shaped member obtained in the above step, and foaming and curing the expandable binder, and a method for producing a molded body. 2. The foamable binder is a urethane raw material, and is 20% by weight or more and 40% by weight or less of the total weight of the mat-shaped member.
The method for producing a molded body according to claim 1, wherein the content is not more than wt%. 3. A molded product obtained by the method according to claim 1. 4. A molded product containing a wood-based fiber material and a binder, wherein the content ratio of the wood-based fiber material decreases from one side to the other side in the thickness direction of the molded product. The molded body having a gradient composition in which the content of is increasing from the one side to the other side in the thickness direction of the molded body. 5. A molded article containing a wood-based fiber material and a binder, wherein the content rate of the wood-based fiber material increases on one surface layer side and the other surface layer side of the molding and decreases at the central portion. , The content of binder is
A molded product having a graded composition that decreases on the one surface layer side and the other surface layer side and increases on the central part. 6. The molded product according to claim 4, wherein at least a part of the binder has a foam structure.