JPH03219923A - Sheetlike molding material - Google Patents

Abstract

PURPOSE:To constitute the title material so that an ingredient composition and a weight per unit area are uniform extending over the whole of a sheet and paste of a sheetlike molding material is not forced out from edges of a film at the time of manufacturing, by a method wherein both end parts of a widthwise direction of s sheet of the film is folded back in the central direction. CONSTITUTION:After two sheets of films to which thermosetting resin past 2 is applied are put together by placing a glass fiber reinforcement material between them, edges (both side fringe parts) of two sheets of the films 1a, 1b are folded back in the central direction prior to winding-up of the sheet round a roll or folding-up of the sheet prior to press-bonding with a roller group or after the press-bonding with the roller group to infiltrate thermosetting resin paste into the glass fiber reinforcement material. In this instance, it is preferable that a bending position of the film is an edge part of the film and is position where a molding material extended to both sides by being rolled is in existence. In addition, in the case where the edge part of the film is bent, it can be prevented that the bent edge part is restored to the original state by a method wherein the film is wound immediately in a rolled state under that state or folded up.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides a sheet-like molding material ( 6 "Prior Art" Regarding Sheet Molding Material (SMC) 1For example, as shown in FIG. 7, between thermosetting resin paste layers 2a and 2b formed on two films la and lb, It is constructed by sandwiching a glass fiber reinforcing material 3.A mixture of the thermosetting resin paste layers 2a, 2b and the glass fiber reinforcing material 3 forms the molding material 4.In this case, the thermosetting resin The paste layers 2a and 2b are made of a composition containing, for example, a thermosetting resin such as an unsaturated polyester resin, a low shrinkage agent, an initiator, a mold release agent, a filler, a thickener, etc. This sheet-shaped molding material Before use, peel off the films la and lb,
A desired molded product can be easily obtained by pressing it into a predetermined shape using a press and heating it.

Such a sheet-like molding material is manufactured, for example, as follows. That is, as shown in FIG.
A film la made of polyethylene or the like is pulled out from 1, and the thermosetting resin paste 2 supplied from the material tank 12 is applied onto the film la using a doctor knife 134 to form a thermosetting resin paste layer 2a. Also, roll 14
．． The glass lobing 17 is pulled out from 15 and 16 and cut into a predetermined length using a roving cutter 18 to form chopped strands 19. This chopped strand 19
is deposited on the film la to a predetermined thickness to constitute the glass fiber reinforcing material 3.Furthermore, another film 1b is pulled out from the roll 20, and the thermosetting resin paste 2 supplied from the material tank 21 is applied to the doctor knife 22. By film l
b to form a thermosetting resin paste layer 2b. Then, the thermosetting resin paste layer 2a of the film la
The thermosetting resin paste layer 2b of the film tb is bonded together with the glass fiber reinforcing material 3 sandwiched therebetween, and the roller group 23 is used to press the layer 2b. The sheet thus obtained is wound onto a roll 24 and stored. After curing for a predetermined period, the thermosetting resin paste layers 2a and 2b become tack-free.
Even if the films la and lb are peeled off, they cannot be touched.

[Problems to be Solved by the Invention] In the above conventional method, the thermosetting resin paste layers 2a, 2
In order to increase impregnation into the glass fiber reinforcing material 3 of b, it is necessary to press the sheet with a group of rollers 23, and in order to make the product compact, it is necessary to wind the sheet onto a roll 24. At this time, a rolling force is applied to the sheet, and as shown in FIG. 6, the molding material 4 sandwiched between the two films la and lb is
It is spread at both ends (hereinafter referred to as ears) of the sheet in the width direction.

However, since the edges of the two films la and lb are open, the rolled molding material 4 will not reach the film lb.
There was a problem in that the film sometimes protruded from the a and lb portions, and a film that was wider than necessary had to be used.

In addition, the thermosetting resin paste 2 has a glass fiber reinforcing material 3
Since the thermosetting resin paste 2 has higher fluidity than the glass fiber reinforced material 3, it spreads more toward the edge of the sheet than the glass fiber reinforcement material 3. Therefore, the edge of the sheet is
The ratio of reinforcing material is higher than that of the central portion, and the weight per unit area is smaller than that of the central portion.

As described above, if the ratio of resin paste/reinforcing material is high in some parts and the weight per unit area is small in some parts, the strength of those parts becomes weak and cracks are likely to occur in the molded product. Furthermore, if the content of the glass fiber reinforcing material is small, pinholes are likely to occur in the molded product. Furthermore, when charging a mold with a sheet molding material, the unit area weight is assumed to be constant and the material is cut into unit areas for use, so if the unit area weight is uneven, it may cause poor charcoal quality.

Therefore, an object of the present invention is to provide a sheet-like molding material whose component composition and unit area weight are uniform over the entire sheet, and whose paste does not protrude from the edges of the film during production. It is about providing.

"Means for Solving the Problems" In order to achieve the above object, the present invention provides a sheet-shaped molded product in which a glass fiber reinforcing material is sandwiched between a thermosetting resin paste layer formed on two films. The material is characterized in that both ends of the film sheet in the width direction are folded back toward the center.

Further, in a preferred embodiment of the present invention, both ends of the film sheet in the width direction are folded back toward the center, and in this state, the sheet is wound into a roll or folded.

Furthermore, in a preferred embodiment of the present invention, both ends of the film sheet in the width direction are folded back toward the center together with the molding material spread on both ends.

Another aspect of the present invention is a sheet-shaped molding material in which a glass fiber reinforcing material is sandwiched between thermosetting resin paste layers formed on two films, in the width direction of the sheet of the film. Hereinafter, the present invention will be described in detail by citing preferred embodiments.

The thermosetting resin paste includes, for example, a thermosetting resin such as an unsaturated polyester resin, a low shrinkage agent such as a thermoplastic resin, a thickener such as magnesium oxide or magnesium hydroxide, and a resin such as zinc stearate. A resin composition containing a mold release agent, a filler such as calcium carbonate or calcium hydroxide, an initiator such as t-butyl peroxybenzoate, and a coloring agent is used.

As the glass fiber reinforcing material, used are chopped strands obtained by cutting roving into lengths of about 1 inch, woven materials such as chopped strand mats, continuous mats, roving cloths, and roving itself. Depending on the application, glass fibers coated with a metal such as aluminum may also be used.

As the film (carrier film) that sandwiches these molding materials, for example, polyethylene, polypropylene, nylon film, etc. are used.

The sheet-shaped molding material (hereinafter abbreviated as SMC) is manufactured by coating a film with a thermosetting resin paste and cutting a glass fiber reinforcing material onto the coated surface, as shown in Figure 8, for example. The thermosetting resin paste coated on the film in the same manner as above was pressed onto it, and the glass fiber reinforcement material was impregnated with the thermosetting resin paste, and the SMC molding material was applied to the two films. This can be done by clamping.

In one aspect of the present invention, after a glass fiber reinforcement material is sandwiched between two films coated with a thermosetting resin paste, the thermosetting resin paste is impregnated into the glass fiber reinforcement material. Before being crimped with rollers,
Alternatively, after being crimped by a group of rollers, the sheet is wound up into a roll, or before the sheet is folded, the edges (both side edges) of the two films are folded back toward the center.

In this case, the preferred position for folding is the edge of the film, where there is molding material that has been rolled and spread on both sides. You can also bend it.

In another aspect of the present invention, after a glass fiber reinforcing material is sandwiched between two films coated with a thermosetting resin paste, the edges of the films are heat-sealed. However, in this case, care must be taken to prevent air from getting mixed in as much as possible.

The SMC of the present invention can be obtained by bending or heat-sealing the edges of the film as described above. This SMC is manufactured by winding it into a roll or folding it to a predetermined length according to a conventional method. The SMC thus obtained is, for example, 35 to
A tack-free state is achieved by aging or curing at 40° C. for about 1 to 4 days.

Note that when the edges of the film are bent, by immediately rolling them into a roll or folding them in that state, the bent edges can be prevented from returning to their original shape. When the film is rolled or folded and left for a while, the viscosity of the thermosetting resin increases, so that the folded film will not return to its original shape.

"Function" In the present invention, the edges of the SMC film are bent or heat-sealed, so when the molding material is sandwiched between the films and then crimped, or when the sheet is wound into rolls or folded, This prevents the molding material from protruding from the edges of the film when the film is rolled.

Therefore, there is no need to use an unnecessarily wide film as in the past.

In addition, by bending or heat-sealing the edges of the film, only the thermosetting resin paste is prevented from flowing to the edges, so the glass fiber content and weight per unit area are lower than those in the edges. Changes between the central part and the center part can be prevented and can be averaged as a whole, which solves problems such as a decrease in local strength, the occurrence of cracks and pinholes, and poor charcoal formation in the mold.

Also, if the edges of the film are bent.

Since the SMC sheet width can be narrowed to the extent that the film does not protrude on both sides, when the SMC sheet is rolled or folded, the edges on both sides are even and can be packaged compactly. Note that even when the edges of the film are heat-sealed, the above effects can be expected because there is no need to make the film width wider than necessary.

Furthermore, when the film flaps are folded back toward the center along with the molding material on both sides, the thermosetting resin spread on both sides is folded back, so the glass fiber content and weight per unit area can be reduced. It can be more averaged.

"Example" Example 1 The composition shown below is a thermosetting resin, a low shrinkage agent, a filler,
A pigment, an internal mold release agent, an initiator, and a thickener were mixed to produce a thermosetting resin paste. In addition, in the following, "part" represents "part by weight".

(Composition of thermosetting resin paste) Thermosetting resin Unsaturated polyester 85 parts Low shrinkage agent Thermoplastic polymer solution 15 parts Filler Calcium carbonate 100 parts Pigment Cream
15 parts Internal mold release agent Zinc stearate
3 parts Initiator: t-butylperoxybenzoate 1 part Thickener: Magnesium oxide 0.7 parts Further, as a manufacturing apparatus, an apparatus as shown in FIG. 8 was used.

However, a folding device as shown in Fig. 3 is installed between the roller group 23 that rolls the sheet and the roll 24 that winds the sheet, and the edges of the films la and lb are mechanically bent at this portion. I did it like that. This folding device 31 has guides 33 on both sides of the sheet conveyance path 32.
a and 33b are provided. This guide 33a, 3
3b is gradually narrowed in the direction of travel so that as the films la and lb advance, the edges of the films la and l'b are raised upwards and then gradually folded back toward the center. It has a curved shape.

The thermosetting resin paste obtained above is applied on each of the two polyethylene films, glass fiber reinforcement (chopped strands) is spread on the thermosetting resin paste layer of the other film, and then thermoset. The two films were put together so that the glass fiber reinforcement material was sandwiched between the resin paste layers.

The amount of glass fiber reinforcement added is 30% in the molding material.
The amount was expressed as % by weight. After the films were combined, they were pressed together with rollers to impregnate the glass fiber reinforcement with thermosetting resin paste. Thereafter, the edges of both sides of the film were folded toward the center using the folding device 31 shown in FIG. 3, and the film was wound into a single roll. This was left to mature at a temperature of 35 to 40°C to obtain the SMC of the present invention.

As shown in FIG. 1, this SMC consists of films la,
A molding material 4 is sandwiched between lb, and a film la
, lb are folded back towards the center together with both side edges of the molding material 4 which has been spread by compression bonding. SM
After C was aged to some extent, the folded portion of the molding material 4 did not return (open) even if the films la and lb were peeled off.

Comparative Example An SMC was obtained in the same manner as in Example 1, using the same thermosetting resin paste, film, and glass fiber reinforcing material as in Example 1, except that the edges of the film were not bent.

Test Example 1 (Measurement of glass fiber content) The SMC obtained in Example 1 was used as an example product, and the SMC obtained in a comparative example was used as a comparative example product. Content rate (%), JIS K 705
It was measured by method 2.

The results are shown in FIG. 4, in which the solid line represents the comparative example product and the broken line represents the example product.

From this result, the glass fiber content of the comparative example product becomes extremely low as it approaches the edge of the sheet, but the glass fiber content of the example product decreases even as it approaches the edge of the sheet.
It can be seen that there is almost no difference from the central part.

Test Example 2 (Measurement of unit area weight) The SMC obtained in Example 1 was used as an example product, and the SMC obtained in the comparative example was used as a comparative example product, and the unit area weight from the edge to the center of the sheet was measured. (kg/m2) was measured.

The results are shown in FIG. In the figure, the solid line represents the comparative example product, and the broken line represents the example product.

From this result, it can be seen that the unit area weight of the Comparative Example product becomes extremely small toward the edge of the sheet, but in the Example product, even at the edge of the sheet, it is almost the same as that at the center.

Example 2 Using the same thermosetting resin paste, film, and glass fiber reinforcing material as in Example 1, the edges of the film were bent.
An SMC was obtained in the same manner as in Example I except that the molding material was not used in the area.

As shown in FIG. 2, this SMC consists of films la,
A molding material 4 is sandwiched between lb, and a film la
, lb are folded back toward the center at the outer part of the molding material 4. In this SMC, the glass fiber content and unit area weight tended to change at the edges compared to the product of Example 1, but were more averaged than the products of Comparative Example.

Example 3 Using the same thermosetting resin paste, film, and glass fiber reinforcement as in Example 1, an SMC was made in the same manner as in Example 1, except that the edges of the film were heat-sealed instead of being bent. Obtained.

This S&IC also had a tendency for the glass fiber content and unit area weight to change at the edges compared to the product of Example 1, but they were more averaged than the products of Comparative Example.

"Effects of the Invention" As explained above, according to the present invention, since the edges of the SMC film are bent or heat-sealed, it is possible to prevent the molding material from protruding from the edges of the film.

In addition, since only the thermosetting resin paste is prevented from flowing to the periphery when the sheet is crimped, rolled up or folded, the glass fiber content and unit area weight can be reduced throughout the sheet. It is made uniform, and problems such as a partial decrease in strength, the occurrence of cracks and pinholes, and poor charcoal formation in the mold do not occur.

Furthermore, compared to conventional SMC, the sheet width can be narrower even with the same weight, so products can be packaged more compactly.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the sheet-like molding material according to the present invention, FIG. 2 is a sectional view showing another embodiment of the sheet-like molding material according to the present invention, and FIG. A plan view showing an example of a folding device, FIG. 4 is a chart showing the glass fiber content from the center of the sheet to the edge of the example product and the comparative example product, and FIG. 5 is the sheet of the example product and the comparative example product. A chart showing the unit area weight from the center to the ear. Figure 6 is a sectional view showing an example of a conventional sheet-shaped molding material. Figure 7 is a schematic sectional view of the same sheet-shaped molding material. Figure 8 is a sheet. FIG. 2 is an explanatory diagram showing a general manufacturing apparatus for shaped molding material. In the figure, la and lb are films, 4 is a molding material, 31 is a bending device, and 33a and 33b are guides.

Claims (4)

[Claims] (1) In a sheet-shaped molding material formed by sandwiching a glass fiber reinforcing material between thermosetting resin paste layers formed on two films, both ends of the film sheet in the width direction are aligned toward the center. A sheet-shaped molding material characterized by being folded back. (2) The sheet-shaped molding material according to claim 1, wherein both ends of the film sheet in the width direction are folded back toward the center, and in this state, the sheet is wound into a roll or folded. (3) The sheet-like molding material according to claim 1 or 2, wherein both ends of the film sheet in the width direction are folded back toward the center together with the molding material spread on both ends. (4) In a sheet-shaped molding material formed by sandwiching a glass fiber reinforcing material between thermosetting resin paste layers formed on two films, both ends of the film sheet in the width direction are heat-sealed. A sheet-shaped molding material characterized by: