JP3389898B2 - Thermoplastic material molding method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a thermoplastic material mainly used as a core material for automobile doors.

[0002]

2. Description of the Related Art Conventionally, in order to mold a thermoplastic material of this type, a molding material is heated by a far infrared heating device or a hot air heating device to be plasticized, and then inserted into a predetermined molding die and cold-compressed. Was there.

[0003]

However, in this case, heating unevenness occurs due to variations in the temperature distribution of the far-infrared heating device or the hot air heating device, and in order to plasticize the entire molding material, a thermoplastic resin is used. The melting temperature must be higher than the melting temperature, and the molding material will be partially burnt.
Further, since the heating is indirect, that is, the temperature of the atmosphere is raised to raise the temperature of the molding material, the heating time becomes long. Further, there is a disadvantage that deformation or shrinkage occurs due to heat depending on the properties of the molding material.

In order to avoid such an inconvenience, a method of thermally compressing the molding material with a pressing device can be considered.
This method has the drawback that when the thermoplastic material obtained by thermal compression is taken out of the press, the thermoplastic material sticks to the hot plate and delaminates due to its high tackiness.

In view of the above circumstances, the present invention can plasticize the molding material as a whole without burning, shortens the heating time of the molding material, and prevents deformation and shrinkage of the molding material. It is an object of the present invention to provide a method for molding a thermoplastic material that is capable of preventing delamination from occurring.

[0006]

[Means for Solving the Problems] That is, according to the present invention, a molding material (3) in which a fibrous material is mixed with a thermoplastic resin is pressed through a seat belt (5A, 5B) by a pressing device (6).
And plasticize by heat compression with a pair of hot plates (6c, 6d), and then, with both front and back surfaces of this molding material sandwiched between the seat belts, cooled by cooling nose bars (21A, 21B) to be semi-cured. , then, this molding material is moved away from the seat belt to prepare a thermoplastic material (7), then there the thermoplastic material in a molding process of thermoplastic material to cure in a predetermined shape by cold compression The molding material
When separating from the seat belt (5A, 5B)
The seat belt using the cooling nose bar.
It is configured to be folded at an angle of 0 ° or more . here
And, the cooling nose bar works with the cooling rolls (8A, 8B).
The cooling nose bar may be used alone.
Absent. By adopting such a configuration, the plasticizing of the molding material is performed in such a manner that each hot platen of the pressing device holds the entire molding material and directly heats it uniformly.
The thermoplastic material is prepared so that the thermoplastic resin on both the front and back surfaces of the molding material is semi-cured and is separated from the seat belt. Besides, the material of the seat belt is releasable
Even if it is not excellent in seat belt
It becomes easy to release from.

[0007]

Further, in the present invention, the thermoplastic material (7) before cold compression is formed into a plate shape. With such a configuration, the handling property of the thermoplastic material at the time of cold compression is improved, and the handling thereof becomes easy.

Here, as the above-mentioned fibrous material, an organic fibrous material such as wood fiber having a fiber length of 5 to 20 mm obtained by steam-defibrating wood chips can be used as a main aggregate. Entangled with this organic fiber material acts as a skeleton aggregate,
Fiber length 10-50m to improve moldability and strength characteristics
An inorganic fiber material or an organic fiber material having a thickness of m and a thickness of 10 to 30 μm may be mixed. These inorganic fiber materials and organic fiber materials are preferably those which are excellent in tensile strength and rigidity and can be obtained at a relatively low cost, and depending on the required performance, in addition to glass fibers, inorganic fiber materials such as rock wool and ceramic fibers and Organic fiber materials such as carbon fiber, aramid fiber, hemp and cotton can be used.
When using natural fibers such as hemp and cotton, it is difficult to fix the fiber length and thickness, and the dispersibility during mixing is poor,
Further, since the strength and rigidity of the fiber itself is small, the moldability or the physical properties of the molded product are slightly deteriorated as compared with the glass fiber, so it is necessary to use them properly according to the required performance.

As the thermoplastic resin, 160
A high melting point thermoplastic resin (for example, polypropylene resin, polyamide resin, etc.) that melts at a high temperature of ℃ or more and acts as a binder effect and an adhesive for the skin material can be adopted, and its properties are fibrous and powder. It may be in the form of liquid or liquid. In the case of a fibrous thermoplastic resin, a woven fabric of polypropylene fibers, a carpet or the like may be used, which is called fluff. When polypropylene recycled fiber is used as a thermoplastic resin, the cost is low and the resource is reused.

On the other hand, as the seat belt, a composite of a woven cloth woven of heat resistant fibers such as glass fibers coated with a synthetic resin such as a fluororesin having an excellent releasability can be applied. From the aspect, the thickness is 0.1-
About 0.5 mm is desirable.

Further, the temperature of each heating plate of the above press device is
It may be set to a temperature higher than the melting point of the thermoplastic resin of the molding material (a temperature higher than this melting point by about 60 ° C. is desirable). The heating time is set according to the weight per unit area of the molding material, but generally it is about 20 to 40 seconds (when the weight per unit area is 1.6 to 2.0 kg / m ² ).

Further, the surface temperature of the cooling nose bar is preferably 30 to 90 ° C. This surface temperature is 3
If the temperature is lower than 0 ° C, the temperature of the front and back surfaces of the molding material is large, the thermoplastic resin is hardened, and the follow-up to the molding die becomes insufficient during cold compression molding, resulting in partial breakage and wrinkles. Etc. may occur. On the contrary, when the surface temperature of the cooling nose bar is higher than 90 ° C., the cooling is not sufficient and the molten thermoplastic resin sticks to the seat belt and sticks to it.

The reference numerals in the parentheses are for convenience of representing the corresponding elements in the drawings, and the present invention is not limited to the description in the drawings. This also applies to the "Claims" section.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing an example of a thermoplastic material molding facility to which an embodiment of the method for molding a thermoplastic material according to the present invention is applied.

As shown in FIG. 1, this thermoplastic material molding equipment 20 has a dry felt molding apparatus 1, and two conveyor belts 14 and 15 are rotatably driven in front of the dry felt molding apparatus 1. It is arranged freely. A needle punching device 17 and a dryer 13 are attached to the conveyor belt 14, and a cutting machine 4 is installed between the conveyor belt 14 and the conveyor belt 15.

The first belt is provided in front of the conveyor belt 15.
Seat belt 5A is cooling roll 8A, drive roll 11
It is arranged so as to be rotatably driven by being suspended from A or the like.
On the other hand, above the first seat belt 5A, a second seat belt 5B is rotatably driven by a cooling roll 8B, a driving roll 11B and a driven roll 18, and the cooling roll 8B and the driven roll 18 are respectively arranged. It is supported by a cylinder 9 and a cylinder 19 so as to be vertically driven. Further, the cooling roll 8B and the driven roll 18
The tension adjusting rolls 12 are disposed in the vicinity of the above, respectively, in contact with the second seat belt 5B. Each of the seat belts 5A and 5B is a composite of heat-resistant fiber woven cloth (for example, glass fiber woven cloth) coated with fluororesin. Further, both the cooling rolls 8A and 8B are maintained at a predetermined surface temperature (for example, 60 ° C.). And FIG.
As shown in, each of the cooling rolls 8A and 8B is in front of it.
Cooling nose bars 21A and 21B are installed side by side.
The belts 5A and 5B are the cooling nose bars 21 respectively.
It is also suspended in A and 21B. The cooling unit located on the lower side
As shown in FIG. 4, the bar 21A has a triangular tubular shape.
The main body 21a has a tip angle α of 90
It has become °. Further, the water passage 2 is provided in the bar body 21a.
1c is formed, and the cooling water flows through this water passage 21c.
The cooling nose bar 21A can be cooled by
it can. On the other hand, the cooling nose bar 21B located on the upper side
Is symmetrical with the cooling nose bar 21A as shown in FIG.
It has a unique shape.

A press device 6 is attached to the seat belts 5A and 5B, and the press device 6 is provided with a ram 6a which can be lifted and lowered. An upper heating plate 6c is attached to the tip of the ram 6a. When the ram 6a is lowered, the upper heating plate 6c contacts the upper surface of the seat belt 5B and further presses the seat belt 5B downward. On the other hand, Ram 6
A base 6b is installed below a.
A lower heating plate 6d is attached to the upper surface of the above so as to abut the lower surface of the seat belt 5A and face the upper heating plate 6c.

Further, a carry-out belt 10 is rotatably driven in front of the seat belt 5A.

Since the thermoplastic material molding equipment 20 has the above-mentioned structure, when molding the thermoplastic material in the thermoplastic material molding equipment 20, the following procedure is performed.

First, the conveyor belts 14 and 15, the seat belt 5A, and the carry-out belt 10 are rotated, and the upper heating plate 6c and the lower heating plate 6d of the pressing device 6 are set to a predetermined temperature (of the thermoplastic resin of the molding material 3). A high temperature thermoplastic resin (such as polypropylene resin) and a fibrous material (such as wood fiber) are uniformly diffused and mixed in a state where the temperature is raised to a temperature equal to or higher than the melting temperature, for example, 60 ° C., and a dry felt molding apparatus is provided. Throw in 1. Then, the fleece 2 is made into paper in the dry felt forming apparatus 1, and the conveyor belt 14
Supplied on. Then, the fibers of the fleece 2 are three-dimensionally entangled by a needle punching device 17 to mechanically bond them, dried by a dryer 13 to retain the shape, and then cut into a predetermined length by a cutting machine 4 to be bulky. The mat-shaped molding material 3 is supplied to the seat belt 5A via the conveyor belt 15.

Thus, the molding material 3 is the seat belt 5A.
When the upper part of the press device 6 is advanced to reach the position just above the lower heating plate 6d of the pressing device 6, the rotation of the seat belt 5A is interrupted and the forming material 3 is stopped. In this state, the cylinders 9 and 19 are driven to lower the cooling roll 8B and the driven roll 18, and the ram 6a of the press device 6 is lowered. Then, the molding material 3 is heat-compressed in the thickness direction by the upper heating plate 6c and the lower heating plate 6d of the pressing device 6 which is held at a predetermined temperature, and has a predetermined bulk density (for example, 0.5 to 0.9
g / cm ³ ).

At this time, the front and back surfaces of the molding material 3 are evenly heated by contacting the upper heating plate 6c and the lower heating plate 6d of the pressing device 6 over the entire surface thereof, so that the upper heating plate is tried to overcome uneven heating. The situation that the temperature of 6c and the lower heating plate 6d rises too much and the molding material 3 burns does not occur. Also, molding material 3
Is heated directly by the upper heating plate 6c and the lower heating plate 6d of the pressing device 6, so that the heating time of the forming material 3 can be shorter than indirect heating. Further, since the molding material 3 is sandwiched between the upper heating plate 6c and the lower heating plate 6d of the pressing device 6 and is restrained from being deformed, the deformation or shrinkage of the molding material 3 due to heat is suppressed.

When the molding material 3 having a predetermined bulk density is obtained in this way, the ram 6a of the pressing device 6 is raised and then the seat belts 5A and 5B are rotated. Then, the molding material 3 passes between the cooling rolls 8A and 8B while being sandwiched between the seat belts 5A and 5B, and is then supplied onto the carry-out belt 10 as the plate-shaped thermoplastic material 7. At this time, the molding material 3 is cooled by the cooling rolls 8A and 8B through the seat belts 5A and 5B, and the thermoplastic resin on both front and back surfaces of the molding material 3 is semi-cured, so that the molding material 3 has high adhesiveness. Therefore, there is no risk of delamination by sticking to the seat belts 5A and 5B. Also cold
Seat belt 5 with the nose bars 21A and 21B
Molding material 3 regardless of A or 5B material (excellence of mold releasability)
Can be easily released from the seat belts 5A and 5B.
It will be possible. That is, when the cooling rolls 8A and 8B are used alone
(See FIG. 1), depending on the material of the seat belts 5A and 5B,
As shown in FIG. 2, the uncured molding material 3 is
Sheet due to the adhesiveness of the thermoplastic resin contained in it
Be stuck on one of the belts 5A, 5B
It may happen. On the other hand, the cooling nose bar 21
When A and 21B are installed together, the molding material 3 is shown in FIG.
Through the seat belts 5A and 5B
Seat belts 5A, 5 after being cooled by A, 8B
Cooling is also performed by cooling nose bars 21A and 21B through B.
And the thermoplastic resin on both the front and back sides is fully semi-cured.
It At this time, the seat belts 5A and 5B are the cooling rolls 8
Line contact with A and 8B, while cooling nose bar 2
1A and 21B are in surface contact with each other and the contact area is expanded,
Cooling the molding material 3 with the cooling nose bars 21A and 21B.
The rejection effect is high. Moreover, the seat belts 5A and 5B are
Pass through the tip of each cooling nose bar 21A, 21B
The vertical direction from the previous horizontal direction to
The material 3 for molding is a seat belt because it is folded back after changing its shape.
Straight water without sticking to 5A and 5B
It is sent out flat and supplied onto the carry-out belt 10. Na
The tip angle α of the cooling nose bar 21 is not always 90 °.
Without being limited, if the angle is 110 ° or less, the molding material 3
Entrainment can be avoided. For example, a cooling nose
When the tip angle α of the bar 21 is 110 °, the seat belt 5
A and 5B are folded back at 70 ° and the tip of the cooling nose bar 21
When the edge angle α is 60 °, the seat belts 5A and 5B are 12
It will turn back at 0 °.

After that, the thermoplastic material 7 is removed from the carry-out belt 10.
It moves upward and shifts to a cold compression process, and is inserted into a predetermined molding die (not shown) and cold compressed. Then, the thermoplastic material 7 is completely cured into a predetermined shape (for example, the shape of the core material of the automobile door). At this time, since the thermoplastic material 7 is plate-shaped from being supplied onto the carry-out belt 10 to being cold-compressed, it is excellent in handleability in the cold-compression process and easy to handle.

The molding of the thermoplastic material 7 is completed when the thermoplastic material 7 is hardened into a predetermined shape by cold compression.

In the above-described embodiment, the case where the needle punching device 17 and the dryer 13 are used to hold the shape of the fleece 2 has been described, but a heat-melting resin having a low melting point (for example, polyethylene, polyester, etc.) is used. May be mixed in the fleece 2 and the fleece 2 may be heated by a hot air ventilation device (not shown) to bond the fibers in the fleece 2 with a heat fusion resin to retain the shape.

Further, in the above-mentioned embodiment, the case where the thermoplastic material of a predetermined length is molded by using the thermoplastic material molding equipment 20 equipped with the batch type press device 6 has been described, but the hot platen is continuous. The present invention can also be applied to the case where an infinitely long thermoplastic material is molded by a continuous pressing device (not shown) that thermally compresses while rotating it.

[0030]

[0031]

[0032]

[0033]

EXAMPLES Examples of the present invention will be described below.

Example 1 By applying the present invention, a fleece composed of the following components was made into a paper, and a bulky mat having a bulk density of 0.1 g / cm ³ , a basis weight of 2.0 kg / m ² , and a thickness of 20 mm was used. A shaped material for molding was obtained. Wood fiber (water content 30% or less) 40 parts by weight Hemp fiber 10 parts by weight Polypropylene fiber (melting point 170 ° C) 50 parts by weight

A hot platen temperature of 220 to 230 is applied to this molding material.
Heat compression was performed for 30 seconds at a temperature of 490,000 Pa (= 5 kg / cm ² ). As the seat belt, a woven glass fiber cloth coated with a fluororesin was used. The surface temperature of each cooling roll was 50 ° C. As a result, the material temperature is 200 ~ 210 ℃, and the thickness is 2.5 ~ 3.0mm.
A thermoplastic material was obtained.

This thermoplastic material was molded at a mold temperature of 50 ° C. or lower,
Cold compression was performed under the conditions of a compression surface pressure of 980,000 Pa (= 10 kg / cm ² ) and a compression time of 20 seconds. As a result, a thermoplastic material having a desired shape was obtained without surface defects, shrinkage or scorching.

Example 2 Instead of a bulky mat-shaped molding material, a bulk density of 0.8 g / cm ³ and a basis weight of 2.0 kg /
A thermoplastic material having a desired shape was molded in the same manner as in Example 1 except that a molding material preliminarily processed into a plate shape having an m ² of 2.5 mm was used.

As a result, a thermoplastic material having a desired shape was obtained without surface defects, shrinkage, scorching and the like.

<Comparative Example 1> The surface temperature of each cooling roll was 2
A thermoplastic material having a desired shape was molded in the same manner as in Example 1 except that the temperature was 0 ° C.

In this case, the temperature of the thermoplastic material sandwiched between the seat belts was drastically lowered, and the thermoplastic material stuck to the seat belt, causing partial delamination. Therefore, a dent caused by the stick was formed on both the front and back surfaces of the thermoplastic material. Further, the curing of the polypropylene fibers proceeded so much that the molding die could not be sufficiently followed in the cold compression step, and partial breakage and wrinkles occurred.

<Comparative Example 2> The surface temperature of each cooling roll was 1
A thermoplastic material having a desired shape was molded in the same manner as in Example 1 except that the temperature was set to 00 ° C.

In this case, the molten thermoplastic resin in the thermoplastic material migrated and the wood fibers on both the front and back surfaces adhered to the seat belt to stick. Therefore, dents were formed on both front and back surfaces of the thermoplastic material.

[0043]

As described above, according to the present invention, the upper heating plate 6 of the pressing device 6 is provided with the molding material 3 in which the thermoplastic resin is mixed in the fibrous material via the seat belts 5A and 5B.
c and a pair of heating plates such as the lower heating plate 6d for thermal compression and plasticization, and then the cooling nose bar 21 with both front and back surfaces of the molding material 3 sandwiched between the seat belts 5A and 5B.
A and 21B are cooled and semi-cured, and then the molding material 3 is separated from the seat belts 5A and 5B to prepare a thermoplastic material 7, and then the thermoplastic material 7 is cooled and compressed to a predetermined size. Molding of thermoplastic materials that cure into various shapes
A method for forming the molding material 3 using the seat belt 5A,
When separating from 5B, the cooling nose bar 21
70 of the seat belts 5A and 5B using A and 21B.
Since it is configured to be folded back at an angle of not less than °, the plasticizing of the molding material 3 is performed in such a manner that each heating plate of the press device 6 holds the molding material 3 as a whole and directly heats it uniformly. Since the thermoplastic material 7 is prepared so that the thermoplastic resin on both the front and back surfaces of the molding material 3 is semi-cured and is separated from the seat belts 5A and 5B,
Not only can the molding material 3 be plasticized uniformly without being burned, the heating time of the molding material 3 can be shortened, the deformation and shrinkage of the molding material 3 can be prevented, and the thermoplastic material 7 can be prevented. It is possible to prevent delamination.
In addition, the material of the seat belts 5A and 5B has excellent releasability.
Even if it is not, use the molding material 3 for the seat belt 5A,
Since it is easy to release from 5B,
The effect of preventing the delamination of the conductive material 7 becomes remarkable.
It

[0044]

Further, according to the present invention, since the thermoplastic material 7 before cold compression is formed into a plate shape, the handling property of the thermoplastic material 7 at the time of cold compression is improved and the handling thereof becomes easy. The productivity of the thermoplastic material 7 can be increased.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a thermoplastic material molding facility to which an embodiment of a method for molding a thermoplastic material according to the present invention is applied.

[Fig. 2] Cooling showing a defect when there is no cooling nose bar
It is a front view of the roll vicinity .

FIG. 3 is a cooling roll of the thermoplastic material molding equipment shown in FIG .
It is an enlarged view of the vicinity .

4 is an enlarged perspective view of a cooling nose bar of the thermoplastic material molding facility shown in FIG.

[Explanation of symbols]

3 ... Molding material 5A, 5B ... Seat belt 6 ... Pressing device 6c ... Hot platen (upper hot platen) 6d ... Hot platen (lower hot platen) 7 ... Thermoplastic material 8A, 8B ... Cooling Rolls 21A, 21B ... Cooling nose bar

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Minoru Kinan, 3-8-3 Nihonbashihonmachi, Chuo-ku, Tokyo Mitsui Wood Industry Co., Ltd. (72) Takao Yamada 3-8th, Nihonbashihonmachi, Chuo-ku, Tokyo No. 3 in Mitsui Wood Industry Co., Ltd. (56) Reference JP-A-5-245866 (JP, A) JP-A-4-208418 (JP, A) JP-A-9-234751 (JP, A) JP-A-3 -290439 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B29C 43/02 B29C 43/32-43/34 B29C 43/48-43/52 B29B 11/06-11 / 12

Claims (2)

(57) [Claims] 1. A molding material (3) in which a fibrous material is mixed with a thermoplastic resin is heated by a pair of heating plates (6c, 6d) of a pressing device (6) via a seat belt (5A, 5B). The plastic material is compressed and plasticized, and then the front and back surfaces of the molding material are sandwiched between the seat belts and cooled by cooling nose bars (21A, 21B) to be semi-cured, and then the molding material is removed from the seat belt. is moved away to prepare a thermoplastic material (7), then the thermoplastic material to a molding method of thermoplastic material by cold compression is cured into a predetermined shape, the molding material the seat belt (5A, Away from 5B)
When using the cooling nose bar,
A method for molding a thermoplastic material, characterized in that the belt is folded back at an angle of 70 ° or more . 2. The thermoplastic material (7) before cold compression is formed into a plate shape.
The method for molding a thermoplastic material according to claim 1, wherein the thermoplastic material is molded.