JPH08258166A - Manufacture of thermosetting resin structure - Google Patents

Abstract

PURPOSE: To provide a manufacturing method for a thermosetting resin structure for manufacturing simply the structure of high strength reinforced with short fibers. CONSTITUTION: A manufacturing method comprises a process in which short fibers 5 are sprayed on a mold face of a press molding die 1 in the mold opening state and a plurality of reactive raw materials 7 are sprayed to form a molding material layer, and a process in which the press molding die 1 is mold clamped and the molding material layer is cured by heating under pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermosetting resin structure having high strength.

[0002]

2. Description of the Related Art Conventionally, reaction injection molding [RIM (Reaction In
injection molding]]. RIM is a method in which two types of reactive raw materials are made to collide with each other at high pressure, or they are mixed by a mixer attached to a discharge port, and the mixture is injected and injected into a metal mold. Unlike other thermosetting resin materials, RIM has high reactivity and can aim for high cycle,
Further, since the pressure applied to the mold is low, there is an advantage that the equipment is low in price.

As a resin for RIM, a urethane resin,
Epoxy resins, dicyclopentadiene resins and the like are used. Among them, urethane resins are used for a wide range of applications centering on automobile parts due to the toughness and reactivity of the materials.

RIM is usually used as a resin raw material alone, but when high strength is required as a structure, it may be reinforced with fibers such as glass fibers. As this method, an S-RIM in which a preform mat in which reinforcing fibers are preformed is supplied to the mold surface of a mold and the mold is clamped, and then a reactive raw material is injected and injected into the mold, for example, JP-A-62-62. -54
As described in Japanese Patent No. 755, there is R-RIM in which a raw material obtained by mixing a polyurethane resin raw material with a reinforcing material such as milled fiber or mica is injected and injected into a mold.

[0005]

However, this conventional method has the following problems. First, in the case of S-RIM, it is necessary to preform the reinforcing fibers according to the shape of the product, the preforming process is complicated and the raw material cost is high, and the preformed mat is preformed. There is a problem that it takes a lot of time to set it on the die surface of the press-molding die.

Further, in the case of R-RIM, since it is necessary to mix the reinforcing material into the resin component at a high speed so as to be uniform before injection and injection, a reinforcing fiber having a long fiber length is used as the reinforcing material. There is a problem that a molded product having high strength cannot be obtained because it cannot be mixed and only very short fibers having a fiber length of about 50 to several hundreds μm can be mixed.

The present invention solves the above-mentioned problems of the prior art, and provides a thermosetting resin structure having a high strength reinforced by reinforcing fibers having a longer fiber length than that of R-RIM, to S-RI.
The purpose of the present invention is to provide a method for producing a thermosetting resin structure that can be produced more easily than M.

[0008]

According to the present invention, short fibers are blown onto a mold surface of a press mold in an open state and a plurality of reactivities are applied to the mold surface of a press mold in an open state. It is a method for producing a thermosetting resin structure, which comprises a step of spraying a raw material to form a molding material layer, and a step of clamping a press molding die to heat and pressure cure the molding material layer.

In the present invention, as the fiber material of the short fibers, glass fiber, carbon fiber, organic fiber and the like are used, but glass fiber is preferable from the viewpoint of mechanical performance and economical efficiency.
As the short fibers, for example, chopped strands obtained by cutting the roving of the above fiber material into a certain length by a continuous cutting device having a rotary gear such as a spray-up machine are used.

The cut length of the short fibers is preferably about 10 to 35 mm. If the cutting length is too short, the reinforcing effect is not sufficient, and if it is too long, when the mold for press molding is clamped,
The fluidity of the molding material layer in the cavity deteriorates.
The thickness of the roving used is 1000-9000g /
About km is preferable. If the thickness is too thin, the reinforcing efficiency is not sufficient, and if it is too thick, the impregnability of the reactive raw material is affected.

In order to spray short fibers onto the mold surface of the press-molding die in the mold open state, a method of spraying short fibers cut by a continuous cutting device having a rotary gear with an air nozzle is adopted. It is convenient to spray short fibers cut from the roving. In the present invention, as the plurality of reactive raw materials, for example, a urethane resin raw material obtained by mixing an isocyanate and a polyol at a ratio of about 1: 1 and a curing agent containing a bisphenol type resin and an acid anhydride as main components in about 1 are used. Mixed in a ratio of 1:
An epoxy resin raw material or the like is used.

The injection of the plurality of reactive raw materials is performed while mixing the plurality of reactive raw materials. Examples of the mixing method include collision mixing in which a plurality of reactive raw materials are sprayed from each nozzle and mixed by the pressure, and mixing by a dynamic mixer in which a rotary mixer is mixed at one nozzle tip, but a high discharge amount can be obtained. Collision mixing is preferred. The collision pressure in collision mixing is preferably about 40 to 300 kg / cm ² , although it depends on the viscosity of the raw materials.

It is preferable to spray a plurality of reactive raw materials at a collision speed of about 5 to 20 m / sec. If the collision speed is too slow, the impregnating ability of the reactive raw material into the short fibers will be poor, and if it is too fast, the reactive raw material will bounce off.

The content of fibers in the molding material layer formed from short fibers and reactive raw materials is preferably 10 to 30% by weight. If the fiber content is too low, the effect of reinforcing the fibers is not sufficient, and if it is too high, the fluidity of the molding material layer during press molding deteriorates. Press pressure during press molding is 5 kg / c
It is performed in about m ² .

The present invention will be described below with reference to the drawings.
FIG. 1 is a schematic view illustrating the steps of an example of the method for producing a thermosetting resin structure of the present invention. In FIG. 1, reference numeral 1 denotes a press-molding die, which is composed of an upper die 11 and a lower die 12 and has an outer surface shape of a thermosetting structure to be press-formed at the time of die clamping between the die surfaces. Corresponding cavities are formed.

On the mold surface of the lower mold 12 in the mold open state, the roving 4 is fed out by the continuous cutting device 2 having a rotary gear and cut into a predetermined length, and the short fibers 5 are blown by the air nozzle 3, On the short fiber 5, the reactive raw material 7 is sprayed in a mixed state from the nozzle 61 of the mixing head 6 in which the resin tanks 8 and 9 filled with the reactive raw materials A and B are connected, respectively, to form a molding material layer. To form.

At this time, as shown in FIG. 2, the reactive raw material 7 is jetted in a mixed state from the nozzle 61 onto the mold surface of the lower mold 12 in the mold open state, and the roving 3 is continuously fed onto it. The short fibers 5 cut by the cutting device 2 may be blown by the air nozzle 3. In addition, as shown in FIG. 3, the short fiber 5 cut by the continuous cutting device 2 while the roving 3 is being fed out is sprayed from the nozzle 61 with the reactive raw material 7 in a mixed state at a jet pressure to simultaneously open the lower mold. You may make it spray on 12 mold surfaces.

Next, although not particularly shown, the mold material is clamped to heat and cure the molding material layer, and the mold is opened to form the fiber-reinforced thermosetting resin structure 10 as shown in FIG. obtain.

[0019]

According to the method for producing a thermosetting resin structure of the present invention, a short fiber and a plurality of reactive raw materials are sprayed onto the mold surface of a press-molding mold in a mold open state to form a molding material layer. A reaction consisting of a relatively long short fiber having a reinforcing effect and a plurality of reactive raw materials, which consists of a step and a step of heating and pressurizing and hardening the molding material layer by clamping the press molding die. Of a thermosetting resin structure can be formed, and a thermosetting resin structure having high strength can be easily obtained by clamping the press molding die and heating and curing the molding material layer. .

[0020]

Was produced thermosetting resin structure by EXAMPLES process described with reference to the embodiments Figure 1. As a fiber material for short fibers, glass roving (manufactured by Nippon Sheet Glass Co., Ltd., product name “REN445
0 # ") was used. As the reactive raw material, a polyurethane resin reactive raw material (manufactured by Sumitomo Bayern Co., Ltd., trade name “Baijour 60”) was used.

On the mold surface of the lower mold 12 in the mold open state, the roving 3 is fed and cut by the continuous cutting device 2, and the short fibers 5 are blown by the air nozzle 3, and
Resin tank 8 filled with reactive raw materials A and B,
Nozzle 61 of mixing head 6 in which 9 is connected by piping
Then, the reactive raw material 7 was injected in a mixed state at a speed of 10 m / sec to form a molding material layer.

At this time, the spraying position of the short fibers and the spraying position of the reactive raw material were set to be the same position. The fiber content in the molding material layer was set to 20% by weight. The molding material layer was adjusted to 1200 cc in total. After the mold is clamped and the molding material layer is cured by heating under pressure, the mold is opened and the fiber-reinforced thermosetting resin structure 10 as shown in FIG.
I got The molding time was 3 minutes.

Comparative Example 1 A thermosetting resin structure was obtained in the same manner as in Example except that short fibers were not mixed. The molding time was 3 minutes.

Comparative Example 2 Fiber-reinforced thermosetting in the same manner as in Example except that 20% by weight of glass fiber middle fiber (manufactured by Nippon Sheet Glass Co., Ltd., fiber length 200 μm) was mixed in advance in the reactive raw material. A resin structure was obtained. The molding time was 3 minutes.

Comparative Example 3 A fiber-reinforced thermosetting resin structure was obtained in the same manner as in Comparative Example 1 except that the preform mat was set on the mold surface of the lower mold of the press molding mold. The molding time required 20 minutes.

The flexural strength and flexural modulus of the thermosetting resin structures obtained in Examples and Comparative Examples 1 to 3 were measured. The results are shown in Table 1. The flexural strength and flexural modulus were measured according to JIS K7203.

[0027]

[Table 1]

[0028]

Since the method for producing a thermosetting resin structure of the present invention is constructed as described above, the thermosetting resin structure having a high strength reinforced by short fibers having a relatively long fiber length is provided. The body can be easily obtained.

[Brief description of drawings]

FIG. 1 is a schematic view illustrating steps of an example of a method for producing a thermosetting resin structure of the present invention.

FIG. 2 is a front view illustrating another example of a sprayed state of short fibers and reactive raw materials in an example of the present invention.

FIG. 3 is a front view illustrating still another example of a sprayed state of short fibers and reactive raw materials in an example of the present invention.

FIG. 4 is a perspective view showing an example of a thermosetting structure obtained by the present invention.

[Explanation of symbols]

 1 Press Mold 5 Short Fiber 7 Reactive Raw Material 10 Thermosetting Resin Structure

Claims (1)

[Claims] 1. A step of spraying a short fiber and a plurality of reactive raw materials to form a molding material layer on a mold surface of a press molding mold in an open state, and clamping the press molding mold. And a step of heating and curing the molding material layer to cure the thermosetting resin structure.