JPH0596537A - Production of glass long fiber preform - Google Patents

Abstract

PURPOSE:To reduce the radiation quantity of a glass long fiber mat up to molding after heating in a method for producing a glass long fiber preform by heating the glass long fiber mat formed by bonding glass long fiber strands with a thermoplastic resin to subject the same to press molding by means of a mold. CONSTITUTION:The upper mold 3a and lower mold 3b of a mold for a preform are arranged up and down so as to provide a definite distance and the glass long fiber mat 1 grasped by a clamp frame 2 is horizontally arranged between the upper and lower molds 3a, 3b and heated to the softening temp. of a thermoplastic resin or higher by inserting heaters 4a, 4b in the gaps between the glass long fiber mat 1 and the upper and lower molds 3a, 3b. Thereafter, the heaters 4a, 4b are moved and removed and the glass long fiber mat 1 is held from above and below by the upper and lower molds 3a, 3b to be pressed to mold a glass long fiber preform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of preforming a long glass fiber mat in advance when the long glass fiber is used as a reinforcing core material for a synthetic resin molding.

[0002]

2. Description of the Related Art A preform formed by preforming a long glass fiber mat is used as a reinforcing core material for a synthetic resin molded body. As the long glass fiber mat, there is used one in which hundreds of filaments of glass fiber having a thickness of 10 to 20 μm are bundled and cut, and the thermoplastic resin such as polyester resin is used as a binder and the strands are entangled and bonded. To preform a long glass fiber mat used as a reinforcing core material to manufacture a preform, the long glass fiber mat is cut into a size required for forming a preform, which is a product, and then the clamp frame is used. When the thermoplastic resin is melted and heated to a temperature at which it can be molded by heating it from both sides by sandwiching it with a heater, the long glass fiber mat is sandwiched between the clamp frames, and the concave and convex preform molding dies It is moved to a space between them and press-molded between both molds.

In this conventional method, the heat capacity of the long glass fiber mat impregnated with the thermoplastic resin is small, and the heat radiation amount of the long glass fiber mat is large while moving between the molds after heating. The long glass fiber mat is taken out of the space, and the temperature of the long glass fiber mat is rapidly decreased in a short time during which it is moved between the molds, and the temperature becomes lower than the temperature suitable for molding before molding. There is a drawback that ends up. Therefore, in order to reduce the amount of heat radiation from the long glass fiber mat and prevent the temperature from decreasing, the following method is used.

The distance between the heater and the preform die is made as small as possible, the moving distance of the long glass fiber mat is made as short as possible, and the temperature drop during the movement is reduced.

Heat insulating films are attached to both surfaces of the long glass fiber mat to reduce the amount of heat radiated from the long glass fiber mat after heating, and press molding is performed together with the heat insulating film, and the heat insulating film is peeled off from the preform after molding.

[0006] A heat insulating film is sandwiched between two glass long fiber mats to laminate three layers to increase the heat storage amount of the glass long fiber mats and delay the temperature drop during movement after heating, thereby laminating the three layers. After press molding as it is, three layers are separated to obtain two preforms at the same time.

[0007]

Among the conventional methods for forming a preform, the heat capacity is small in the case of a glass continuous fiber mat having a small basis weight only by shortening the moving distance of the heated continuous glass fiber mat. Therefore, the temperature drops quickly and it is difficult to maintain the molding temperature. In addition, it is necessary to raise the heating temperature of the long glass fiber mat by the amount of temperature decrease due to heat dissipation, which increases energy consumption,
Longer heating time and longer molding cycle.

In the method of sandwiching between the two heat insulating films, the cost of the heat insulating film is excessive, and it is difficult to peel the heat insulating film from the molded preform, and the number of steps is increased.

In the method of sandwiching the heat insulating film between the two long glass fiber mats, the amount of the heat insulating film used is smaller than that of the method, and two preforms can be molded by one press. There is a drawback that a peeling step is required and a difference in size occurs between two preforms molded at the same time.

Therefore, according to the present invention, the heat radiation amount of a long glass fiber mat before heating is reduced without using a heat insulating film, and a long glass fiber mat having a small basis weight is molded at an optimum temperature without being heated to a high temperature. An object of the present invention is to provide a molding method of a preform that can be manufactured.

[0011]

[Means for Solving the Problems] In order to achieve the above object,
As a result of intensive studies by the present inventors, the long glass fiber mat heated between two heaters by the conventional method was taken out from between the heaters and moved between the molds.
On the contrary, move the heater and the mold with the long glass fiber mat sandwiched between the clamp frames fixed, first heat the glass long fiber mat by sandwiching it with the heater, then move the heater and remove it. By moving the preform die and immediately pressing, the glass long fiber mat does not have to move from before heating by the heater to the end of the press, and as a result, heat radiation from the glass long fiber mat is only natural heat radiation, The present inventors have completed the present invention by finding that there is no contact with cold air during the movement of the long glass mat of the conventional method and the temperature can be maintained at a temperature sufficient for molding during press molding.

That is, according to the present invention, a flat mat, which is used as a reinforcing core material for a synthetic resin molding and is formed by binding strands of long glass fibers bound with a thermoplastic resin, is heated by a heater to produce the thermoplastic resin. In a method for producing a long glass fiber preform in which a resin is softened and preformed in a preform die, an upper die and a lower die of the preform die are vertically arranged at a certain distance, and in the middle thereof. The long glass fiber mat sandwiched between the clamp frames is arranged horizontally, and heaters are inserted between the long glass fiber mat and the upper mold and the lower mold to heat the long glass fiber mat above the softening temperature of the thermoplastic resin. After that, the heater is moved and removed, the upper mold and the lower mold are fitted from above and below by sandwiching the glass long fiber mat, and pressed to form a glass long fiber preform. And gist of the production method of las filament preform.

Next, the contents of the present invention will be described in detail with reference to the drawings. The glass fiber mat used in the method for producing a preform of the present invention randomly arranges a strand of hundreds of long glass fibers having a thickness of 10 to 20 μm, and a thermoplastic resin such as a polyester resin as a binder is arranged on the strand. A material in which the strands are adhered to each other after being added is used.

In order to form a long glass fiber mat, the size necessary to leave a portion protruding outside the press die after the press is taken into consideration in that the long glass fiber mat is first caught in the die depending on the deep drawing amount of the die. Then, the long glass fiber mat 1 is cut and sandwiched between the clamp frames 2 and fixed. This clamp frame 2
The long glass fiber mat 1 fixed to the above is spread between the upper mold 3a and the lower mold 3b of the preform mold 3 and placed between them.
The upper mold 3a and the lower mold 3b are separated by a heater 4a, 4b between the long glass fiber mat 1 and the upper mold 3a and the lower mold 3b, respectively.
Keep the space at which you can move in and out horizontally.

Between the upper mold 3a and the lower mold 3b, heaters 4a and 4b heated to 350 to 450 ° C. are inserted on both sides of the clamp frame 2 of the long glass fiber mat 1 to insert the long glass fiber mat 1 to 120 to 200. Heat to ℃. The heating time is determined according to the basis weight of the long glass fiber mat 1 and the heating temperature, but is preferably 20 to 40 seconds.

After heating the long glass fiber mat 1 to a predetermined temperature, the heaters 4a and 4b are quickly moved in the horizontal direction, and immediately the upper mold 3a and the lower mold 3 of the preform mold 3 are immediately moved.
b is moved from above and below so as to sandwich the long glass fiber mat 1 and pressed. The pressing time is preferably 20 to 60 seconds. A mold release agent is applied to the inner surface of the preform die 3 to prevent the thermoplastic resin of the long glass fiber mat 1 from adhering, and cooling water pipes inside the preform die 3
It is desirable to cool to 0-30 ° C.

After the press molding, the long glass fiber mat 1 is taken out from the preform die 3 to obtain the long glass fiber mat 1.
By cutting off the unnecessary portion of, the target preform 5 is obtained.

[0018]

According to the preform manufacturing method of the present invention, the long glass fiber mat 1 sandwiched between the clamp frames 2 is heated and fixed without moving until the press molding is completed. Therefore, the long glass fiber mat after heating is fixed. The heat radiation from 1 can be extremely reduced.

Glass long fiber mat 1 after heating in the method for producing a preform of the present invention and the conventional method for moving a glass long fiber mat from a heater to a mold for preform 1
Graphs of temperature changes of the above are shown in FIGS. 2 and 3, respectively.

In both graphs, the surface temperature of the long glass fiber mat 1 is measured by a radiation thermometer from the maximum temperature after heating to the completion of pressing. A is the temperature immediately before the pressing, and B is the temperature when the pressing is completed. In the case of the method of moving the long glass fiber mat 1 of the conventional method shown in FIG. 3, the temperature of the long glass fiber mat 1 has already dropped to near room temperature at the stage A immediately before pressing, and the thermoplastic resin is completely cured. Molding is impossible. In the case of the present invention shown in FIG. 2, the temperature of stage A immediately before pressing is a temperature necessary and sufficient for molding, and the product is immediately removed from the clamp frame 2 because it has already been cooled by the preform die 3 when the press is completed. It is possible to remove unnecessary parts without losing shape.

According to the method for producing a preform of the present invention, a long glass fiber mat having a basis weight of 450 g / m ² is 50 cm.
Can be deep-drawn, and by adjusting the molding conditions such as the heater temperature, it is possible to prevent the heat radiation after heating for the glass long fiber mat having a basis weight of 500 g / m ² or less.

[0022]

EXAMPLE As shown in FIG. 1, a preform was manufactured by the method for manufacturing a long glass fiber preform of the present invention by the following steps.

A mold release agent is applied to the preform die 3.

In consideration of the size of the product preform and the area outside the product, the long glass fiber mat 1 having a polyester resin as a binder is cut and sandwiched between the clamp frames 2 (FIG. 1 a).

The heaters 4a and 4b are moved between the clamp frame 2 and the preform molds 3a and 3b to heat the long glass fiber mat 1 from both upper and lower surfaces. Heater 4a,
The temperature of 4b was set to 400 ° C. (FIG. 1b).

After 30 seconds, when the temperature of the long glass fiber mat 1 reaches 130 to 170 ° C., the heating is finished, the heaters 4 a and 4 b are moved in the horizontal direction, and the heaters 4 a and 4 b are retracted to a position where they do not interfere with the press (FIG. 1 c). ).

The long glass fiber mat 1 is pressed from above and below. At this time, the preform die 3 is cooled to avoid adhesion of the thermoplastic resin.

Pressing is completed after 20 to 40 seconds, the preform die 3 is vertically separated, and the product preform 5 is taken out from the clamp frame 2 (FIG. 1c).

A portion outside the product is cut off and held so that the thermoplastic resin does not lose its shape until the thermoplastic resin is completely cured, to obtain a finished product (FIG. 1d).

[0030]

According to the method for producing a long glass fiber preform of the present invention, the heat radiation amount before the molding of the long glass fiber mat after heating is reduced without using a heat insulating film,
Even a long glass fiber mat having a small basis weight can be molded at the optimum temperature.

The preform produced by the method of the present invention does not have the fibers torn during press molding and has uniform physical properties. When this is used as a reinforcing core material and integrally foamed with polyurethane foam, A molded product with excellent quality can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a long glass fiber preform of the present invention.

FIG. 2 is a graph showing a temperature change of the long glass fiber mat in the method for producing a long glass fiber preform of the present invention.

FIG. 3 is a graph showing a temperature change of a long glass fiber mat in a conventional method for producing a long glass fiber preform.

[Explanation of symbols]

 1 Glass long fiber mat 2 Clamp frame 3 Preform die 4 Heater 5 Preform

Claims (1)

[Claims] 1. A flat mat, which is used as a reinforcing core material for a synthetic resin molded body and is formed by binding strands of long glass fibers bound together with a thermoplastic resin, is heated by a heater to soften the thermoplastic resin. In the method for producing a long glass fiber preform to be preformed by a preform die,
The upper die and the lower die of the preform die are vertically arranged with a certain distance therebetween, and a long glass fiber mat sandwiched by a clamp frame is horizontally arranged between the upper die and the lower die. A heater is inserted between the lower molds to heat the glass long fiber mat above the softening temperature of the thermoplastic resin, and then the heater is moved to remove the upper and lower molds from above and below the glass length. A method for producing a long glass fiber preform, which comprises forming a long glass fiber preform by sandwiching and fitting a fiber mat and pressing.