JPH07108511A - Woody thermoplastic molding plate material - Google Patents

Abstract

PURPOSE:To mold a surface skin material simultaneously and integrally with a core material, which has excellent moldability and processability, is light in weight, has high strength and air permeability by using thermoplastic resins having melting points different from each other. CONSTITUTION:A woody fiber of 30-50 pts.wt., an inorganic fiber or organic fiber of 5-15 pts.wt., and thermoplastic resins having melting points different from each other of 40-60 pts.wt. are mixed and compressed by heat melting to a bulk density of 0.2-0.8g/cm<3>. Accordingly, a fleece 2 is made by a dry felt forming device 1 and heated by a continuous hot blast ventilating heating device 3 so as to obtain a bulky mat. After the mat 5 is cut into a predetermined dimension by a cutting machine 4, it is compressed and heated by a pair of heated heating flat plates 6, taken out in a state that a polypropylene resin fiber is melted, and cooled by a cooling device 7 having a pressure roll. Thus, a woody thermoplastic molding plate material 9 having the shape of a flat plate is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is mainly applied to automobile doors,
The present invention relates to a molding plate material for a core material of interior parts such as rear parcels. More specifically, this thermoplastic molding plate material for a core material is plasticized and softened by heating to form a skin material and a molding material for a soft core material. The present invention relates to a wood-based thermoplastic molding plate material that is cold-compressed in a mold and is integrally molded at the same time.

[0002]

2. Description of the Related Art Conventionally, as a wood-based thermoplastic molding board of this type, polypropylene resin and wood powder are mixed and blended in equal amounts, and then extruded into a flat plate by a T-die extruder to obtain a plate-shaped plate. Generally, a fibrous plate or a powdered inorganic or organic material mixed with a thermoplastic resin to form a plate.

[0003]

However, the above-mentioned wood-based thermoplastic molding sheet generally has a specific gravity of 0.9 g.
It was as large as / cm ³ or more and was heavy. Also,
Since a large amount of inexpensive wood powder is mixed with expensive synthetic resin, the material cost is low, but the addition of these wood powder causes embrittlement of the synthetic resin material, resulting in impact resistance and bending. It has been pointed out that the strength is low.

Furthermore, when the shape of the molded product is deep and complicated and the texture and softness of the skin material are required, an adhesive is applied to the surface of the core material and the core material is superposed on the surface while sucking from the back surface side. A so-called vacuum molding method for adhering the combined skin materials is adopted. However, since the wood-based thermoplastic molding plate material does not have air permeability, there is a disadvantage that it is necessary to process a vent hole of, for example, about 1 mm. It was

As a thermoplastic molding plate material which has solved these drawbacks, a plate material composed of glass fiber and a thermoplastic resin has been developed and is mainly used as a molding core material for an automobile ceiling. Compared with the conventional one, this has less shrinkage during heat plasticization and compression molding, has excellent moldability, and has air permeability, so the bonding process between the skin material and the core material can be arbitrarily selected. . On the other hand, although the molded product is lightweight, it is weak in strength, inferior in compactness, and lacks in rigidity, so that it has poor tack performance. Therefore, it is not suitable for automobile doors, rear parcels, etc., where various metal parts are often riveted to the core material. In addition, there are drawbacks such as high cost due to a large glass fiber compounding ratio, which is not economical, and the uses thereof are limited.

In view of the above circumstances, the present invention provides a wood-based thermoplastic molding plate material which is excellent in moldability and workability, is lightweight, has high strength, and has air permeability, and is capable of integrally molding a skin material and a core material at the same time. The purpose is to provide.

[0007]

That is, according to the present invention, 30 to 50 parts by weight of wood fibers and 5 to 5 inorganic or organic fibers are used.
15 parts by weight and thermoplastic resins having different melting points 40 to 40
60 parts by weight are mixed to obtain a bulk density of 0.2 to 0.8 g / cm ^3.
It is configured by compression heat fusion.

Further, the thermoplastic resin has a melting point of 1
It is configured to include a low melting point resin having a melting point of 20 ° C. or less and a high melting point resin having a melting point of 160 ° C. or more.

[0009]

With the above-mentioned structure, the present invention makes it possible to retain a fiber material such as wood fiber in a bulky mat-like or felt-like material at low temperature by using thermoplastic resins having different melting points. At the same time, it acts so as to give high heat resistance to a molded product obtained by molding this.

[0010]

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

FIG. 1 is a process diagram showing an example of a method for manufacturing a wood-based thermoplastic molding plate material according to the present invention, and FIG. 2 is a process diagram showing another example of a method for manufacturing a wood-based thermoplastic molding plate material according to the present invention. Is.

The wood fiber used in the wood-based thermoplastic molding board according to the present invention acts as a main aggregate, and is for imparting weight reduction, reinforcement, and air permeability. Usually, wood chips are cooked. Disentangled fibers having a fiber length of 5 to 20 mm are used. Water resistance is improved by mixing a proper amount of paraffin wax with the wood chips. Further, the mixing ratio of the wood fiber is preferably 30 to 50 parts by weight. this is,
If the amount is less than 30 parts by weight, the weight reduction, air permeability and strength characteristics of the molded product will be deteriorated, while if it is more than 50 parts by weight,
Since the ratio of thermoplastic resin to wood fiber decreases,
The followability of the molding plate material during compression molding is lost,
This is because the moldability becomes poor.

The inorganic fibers or the organic fibers are entangled together with the wood fibers to act as a supporting aggregate to improve formability and strength characteristics, and have a fiber length of 10 to 5
It is preferably 0 mm and the thickness is about 10 to 30 μm. This is because when the fiber length is shorter than 10 mm, the entanglement with the wood fibers becomes coarse and the uniformity becomes poor, while the fiber length becomes 5
This is because if the length is longer than 0 mm, it will be difficult to achieve uniform mixing. In particular, glass fibers having a fiber length of 10 to 35 mm and a thickness of 10 to 20 μm are particularly excellent in terms of mixability, strength characteristics, and heat resistance. Further, the mixing ratio of the inorganic fibers or the organic fibers is preferably 5 to 15 parts by weight. If the amount is less than 5 parts by weight, the tensile strength and elongation of the plasticizing plate material that has been heated and plasticized are poor, and the moldability is poor. Therefore, not only is it difficult to perform deep drawing, but also the rigidity of the molded product, If the strength is weakened, while if it is more than 15 parts by weight, these characteristics are improved, but the cost is increased.

The inorganic fiber or the organic fiber may be any fiber that is excellent in tensile strength and rigidity and can be obtained at a relatively low cost. Depending on the required performance, other than glass fiber, for example, rock wool, ceramic fiber, or other inorganic material. Fibers, organic fibers such as carbon fibers, aramid fibers, hemp, and cotton can be used, but when using natural fibers such as hemp and cotton, it is difficult to fix the fiber length and thickness, Since the dispersibility at the time of mixing is poor, and the strength and rigidity of the fiber itself are low, the moldability or the physical properties of the molded product are slightly worse than those of glass fiber, so it is necessary to use them properly according to the required performance.

Further, as the thermoplastic resin, two or more kinds having different melting points are used. Specifically, at least a low melting point thermoplastic resin that acts as a binder for maintaining the shape of a bulky mat-like material or felt-like material of a fibrous material by heat melting at a low temperature of 120 ° C. or lower (for example, , Polyolefin resins, polyester resins, etc.) and high melting point thermoplastic resins (for example, polypropylene resins, polyester resins, polyamide resins, etc.) that melt by heat at a high temperature of 160 ° C. or higher and act as a binder effect and an adhesive for skin materials. ) Is used. The mixing ratio is preferably 40 to 60 parts by weight. If the amount is less than 40 parts by weight, the plasticizing of the molding plate material by heating and the followability to the mold deteriorate, resulting in poor molding and poor adhesion of the skin material. The larger the mixing ratio, the better the plasticization of the molding plate material by heating and the followability to the mold, but the density of the molded product becomes high and the weight reduction is hindered, and the air permeability of the molded product also decreases, Further, since the cost becomes higher and it becomes uneconomical, the amount is preferably up to 60 parts by weight.

Here, by using two or more kinds of thermoplastic resins having different melting points, it is possible to retain a fiber material such as wood fiber in a bulky mat-like or felt-like material at low temperature, and The molded product obtained by molding is highly heat resistant. That is, various fiber materials are uniformly mixed and formed into a felt shape or a mat shape with a dry felt forming apparatus or the like, but in this state, the respective fibers are only intertwined with each other, and it is difficult to handle. Therefore, the mat-like material or felt-like material is heated to melt the thermoplastic resin, and the entangled fibers are bonded so that the shape is maintained and the handling becomes easy.

At this time, by using a thermoplastic resin having a low melting point of 120 ° C. or lower, this shape-retaining treatment can be carried out at a low temperature, so that the fiber material does not shrink so much that it can be handled. A uniform mat-like material or felt-like material can be obtained without uneven shrinkage during shaping. The low melting point thermoplastic resin may have a mixing ratio capable of retaining the shape of a mat-like material or a felt-like material so that it can be handled, specifically, 5 to 15 parts by weight of the total thermoplastic resin. If the whole amount is a low melting point thermoplastic resin, the heat resistance of the compression-molded molded product deteriorates, which is not suitable. On the other hand, if the entire amount is made of a high melting point thermoplastic resin, the fiber material is heated at a high temperature when the mat-like material or felt-like material is held at a shape that can be handled, so that the mat-like material or felt-like material shrinks. Since it expands in the thickness direction, desired handling cannot be performed, and there is a problem in that workability is deteriorated, which is not preferable.

The high melting point thermoplastic resin heats and plasticizes the thermoplastic molding plate material, and at the same time, the skin material is cold compression molded into a desired shape by a die to integrally mold the skin material and the core material. It serves as a binder in this case and gives strength to the molded product, and also serves as an adhesive that bonds the skin material and the core material. As a result, the formed molded article has heat resistance.

The thermoplastic resin may be in the form of fibers, powder or liquid, but in the case of powder it is necessary to use fine powder of 100 μm or less in order to mix with the fiber material. There is. When this fibrous material is used, a woven fabric made of polypropylene fiber, a carpet or the like, which is defibrated, may be used. When polypropylene recycled fiber is used as the thermoplastic resin,
The cost will be low and it will contribute to the reuse of resources.

Further, various fiber materials are uniformly mixed and then formed into a felt-like or mat-like shape by a dry felt forming apparatus. The felt-like or mat-like material has a bulk specific gravity of 0.08 g / Since it is not more than cm ^3, it is difficult to convey, and there are problems in handling such as being bulky, and there is a problem in moldability due to large shrinkage due to heating in the subsequent compression molding process. Therefore, the felt-like material or mat-like material is
~ 200 ℃, and pass through a pressure roll,
Bulk specific gravity of 0.2 by heat compression with a heating flat plate at 180-200 ℃
It is a flat plate-like thermoplastic molding material of 0.8 g / cm ³ . If the bulk specific gravity is less than 0.2 g / cm ³ , the thermoplastic molding plate material shrinks when heated in the compression molding process, and good molding cannot be performed. On the other hand, the bulk specific gravity is 0.8 g / cm ^{3 or} more. If it is large, the specific gravity of the molded product becomes large, the weight reduction and the air permeability are impaired, and an excessive pressure is required when it is compressed into a flat plate shape, resulting in an increase in manufacturing cost.

Next, the bulk specific gravity is 0.2 to 0.8 g / cm.
The flat plate thermoplastic molding plate of ³ is heated by a hot air ventilation heating device or far infrared heating device to 180 to 200 ° C., and a core material for a car door or the like consisting of a pair of male and female with the skin material set is formed. Quickly insert into mold for surface pressure 10kg
It is possible to obtain a molded product in which the skin material is integrally molded by cold compression molding at about / cm ² .

Example 1 35 parts by weight of wood fiber dried to a water content of 30 wet% or less, 15 parts by weight of polypropylene resin fiber having a melting point of 170 ° C. and 35 parts by weight of recycled fiber obtained by disintegrating polypropylene woven cloth,
To 10 parts by weight of glass fiber (thickness 10 to 20 μm, length 25 mm), 5 parts by weight of polyester resin fiber having a melting point of 120 ° C. was charged into a mixer and uniformly diffused and mixed, and as shown in FIG. The fleece 2 is made into paper by the molding device 1, and the continuous hot air ventilation heating device 3 is used for 6 at a temperature of 110 to 130 ° C.
Heating for 0 seconds, basis weight 2 kg / m ² , bulk specific gravity 0.08
A bulky mat 5 with g / cm ³ was obtained.

Next, the mat 5 is cut into a predetermined size by a cutting machine 4, and then a pair of heating flat plates 6 heated to 200 ° C.
By compressing and heating with, and taking out the polypropylene resin fiber in a molten state, and cooling it with a cooling device 7 having a pressure roll,
A plate-like wood-based thermoplastic molding plate 9 having a thickness of 2.5 mm and a bulk specific gravity of 0.8 g / cm ³ was obtained.

Then, the wood-based thermoplastic molding plate material 9 is used.
The surface temperature is 180 ° C with a far infrared heating device (not shown)
It is softened by heating until it becomes, and it is quickly inserted into a mold (not shown) for molding automobile door core material consisting of a pair of male and female with a polyester woven skin material set, and a surface pressure of 10 kg / cm.
Cold compression molding was performed at about ² to obtain a molded automobile door core material to which the skin material was integrally bonded. The molded product had good appearance, good texture of the skin material, and good adhesiveness.

Regarding the air permeability, using a truncated cone molding die having a predetermined cross-sectional shape (height: 30 mm, top diameter: 150 mm), a molded article without a skin material is cored in the same manner as the automobile door. The material was molded, an adhesive was applied to the molded core material, and a corresponding vacuum-type non-breathable skin material was attached to measure the adhesive force, and the quality of the air permeability was determined. Further, a flat plate to which a skin material was not adhered was molded for a physical property test, and its characteristics were measured according to JIS-A-5906 (hard fiber board test standard). The results are shown in Tables 1 and 2.

Example 2 Cold compression molding was carried out in the same manner as in Example 1 except that hemp fluff fibers having a thickness of about 30 μm and a length of about 10 to 50 mm were used in place of the glass fibers in Example 1. An automobile door core molded product was obtained. The molded product had good appearance, good texture of the skin material, and good adhesiveness. Further, for the physical property test, a flat plate to which the skin material was not adhered was molded and its characteristics were measured. The results are shown in Tables 1 and 2.

Example 3 The procedure is the same as in Example 1 up to the point of obtaining a bulky mat 5 having a basis weight of 2 kg / m ² and a bulk specific gravity of 0.08 g / cm ³ .
Then, as shown in FIG.
Hot air ventilation heating device with continuous pressure roll at 0 ° C 10
4. While cooling by heating with a cooling device 7 equipped with a pressure roll, and further cut into a predetermined size by a cutting machine 4 to obtain a thickness of 5.
A plate-shaped wood-based thermoplastic molding plate 9 having a diameter of 0 mm and a bulk specific gravity of 0.4 g / cm ³ was obtained.

Then, the wood-based thermoplastic molding plate material was compression-molded in the same manner as in Example 1 except that it was heated to 180 to 190 ° C. by the hot-air ventilation heating device 3 to be plastically softened, and the skin material was integrally bonded. An automobile door core molded product was obtained. The molded product had good appearance, good texture of the skin material, and good adhesiveness.

For the physical property test, a flat plate to which the skin material was not adhered was molded and its characteristics were measured. The results are shown in Tables 1 and 2.

Comparative Example 1 Polypropylene resin and wood powder were mixed at a ratio of 1: 1 and treated with a pressure kneader to be molded, and a commercially available basis weight was 2.5 kg / m ^2.
A wood-based thermoplastic molding plate was subjected to cold compression molding in the same manner as in Example 1 to obtain a molded article, and the characteristics of this molded article were measured. The results are shown in Tables 1 and 2.

Comparative Example 2 An automobile door core material molded product was obtained by cold compression molding in the same manner as in Example 1 except that the glass fiber was not used and the wood fiber was 45 parts by weight in Example 1. The characteristics of the molded product were measured. The results are shown in Tables 1 and 2.

[0032]

[Table 1]

[0033]

[Table 2]

As is clear from Tables 1 and 2, Examples 1 to 3 have better moldability than Comparative Examples 1 and 2, and the skin material can be integrally bonded and vacuum-molded at the same time. The physical properties of the molded product also have sufficient properties as a core material for automobile interior parts.

[0035]

As described above, according to the present invention,
30 to 50 parts by weight of wood fibers, 5 to 15 parts by weight of inorganic fibers or organic fibers, and 40 to 60 parts by weight of thermoplastic resins having different melting points are mixed to obtain a bulk density of 0.2 to 0.8 g.
Since it is composed by compressing and heat-sealing to / cm ³ , by using thermoplastic resins having different melting points, it is possible to retain fiber materials such as wood fibers in bulky mat-like or felt-like materials at low temperature. At the same time, since it becomes possible to impart high heat resistance to the molded product obtained by molding the same, it is possible to provide a wood-based thermoplastic molding plate material having excellent handling characteristics and physical properties. In addition, since wood fibers are used, the compression molded product becomes lightweight and
Since it has excellent breathability, it is of course possible to bond the skin material at the same time as cold compression molding of the wood-based thermoplastic molding plate material, and also for the molded product in which the wood-based thermoplastic molding plate material is molded beforehand. It is possible to process the skin by vacuum forming without processing. Further, since the inorganic fibers or the organic fibers are mixed, the thermoplastic molding plate material which is plasticized by heating has good followability to the mold, excellent moldability, and good strength characteristics.

The thermoplastic resin has a melting point of 1
When it is configured to include a low melting point resin having a melting point of 20 ° C. or lower and a high melting point resin having a melting point of 160 ° C. or higher, it is possible to provide a wood-based thermoplastic molding plate material particularly suitable for interior parts such as automobile doors and rear parcels. It will be possible.

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of a method for manufacturing a wood-based thermoplastic molding plate material according to the present invention.

FIG. 2 is a process drawing showing another example of the method for manufacturing a wood-based thermoplastic molding plate material according to the present invention.

[Explanation of symbols]

 9 ... Wood-based thermoplastic molding board

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kyosuke Aoyama 3-8-4 Nihonbashihonmachi, Chuo-ku, Tokyo Mitsui Lumber Industry Co., Ltd. (72) Akihiro Sasada 3-8-4 Nihonbashihonmachi, Chuo-ku, Tokyo Mitsui Wood Industry Co., Ltd.

Claims (2)

[Claims] 1. A bulk density of 0.2 to 0 is obtained by mixing 30 to 50 parts by weight of wood fibers, 5 to 15 parts by weight of inorganic fibers or organic fibers, and 40 to 60 parts by weight of thermoplastic resins having different melting points. A wood-based thermoplastic molding plate material formed by compressing and heat-sealing to 0.8 g / cm ³ . 2. The wood-based thermoplastic molding plate material according to claim 1, wherein the thermoplastic resin includes a low-melting point resin having a melting point of 120 ° C. or lower and a high-melting point resin having a melting point of 160 ° C. or higher. .