JPH0618692B2 - Method for producing synthetic resin molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a method for producing a synthetic resin molding material comprising a chopped strand obtained by cutting glass roving into short pieces as a fiber reinforcing material.

<Prior Art> There is a vehicle roof, hood, spoiler, mudguard, or the like molded of reinforced plastic.
This reinforced plastic is press-molded with a synthetic resin molding material, which is a mixture of chopped strands obtained by cutting glass roving into short pieces as a fiber reinforcing material.

This synthetic resin molding material is manufactured by the following method. That is, as shown in FIG. 3, two films 1 and 2 made of polyethylene or the like respectively wound on bobbins are rewound, and an unsaturated polyester resin is filled with a surface of the two films 1 and 2 facing each other. A compound 4 composed of a curing agent, a curing agent, a thickener, etc. is applied to the belt conveyor 5, and the glass roving 3 is attached to the cutter roll 9
The chopped strands 6 cut to the required length by the above are sprinkled between the two films 1 and 2 and sandwiched and rolled 7
The sheet material 8 obtained by impregnating the chopped strands 6 and the compound 4 by pressing with is wound on a bobbin, aged for a certain period, and then the impregnated state is inspected and shipped.

In the molding of various products by the sheet material 8, the films 1 and 2 are peeled off, put into a molding die, heated and pressed to mold and harden into desired products.

<Problems to be Solved by the Invention> Although the molded product is coated, pinholes are generated after this coating. The cause of this is as shown in FIG.
The air a1 mixed in the compound 4 has almost no relation to both the air a1 mixed in the compound 4 and the air a2 mixed in the impregnation, and the air a2 mixed in the impregnation is almost irrelevant.
Is involved. That is, the air a2 mixed during the impregnation is the "wettability" between the chopped strand 6 and the compound 4.
Since the sheet material 8 is pressed and filled, the activity is poor in the process of compression molding, and this remains as a burrow in the molded product, and if coating is applied on this burrow, baking will occur. The air in the burrows expands due to the temperature rise at that time, and pinholes are formed by breaking through the coating film that has not yet been cured.

When a binder resin compatible with the compound is used in order to improve the "wettability" between the chopped strand 6 and the compound 4, the chopped strand 6 changes from a strand state to a filament state (this phenomenon is called defibration), and molding is performed. A state where glass fiber not covered with resin is exposed on the surface of the product, or a state where partial swelling or tingling appears due to the difference in the properties of the compatible part between the compound and the binder resin (curling phenomenon) occurs Therefore, it is not a fundamental measure.

A special method is to cut the glass roving with a cutter roll, spray the thermosetting resin onto the chopped strands that drop on the film by a spraying device, and press-mold to a predetermined thickness with a pressure-molding roller. Kai 58-1
In this method, since the thermosetting resin is attached by spraying to the chopped strand that cuts and drops the glass roving, the thermosetting resin is evenly and reliably attached. Is difficult. It is possible to increase the spray pressure as a method to ensure this adhesion, but if the spray pressure is increased, the chopped strands that have been cut will scatter and the mist of the sprayed thermosetting resin will scatter to the surrounding area. There is a problem that stains.
Further, since pressure molding is performed immediately after spraying, there is a problem that it is difficult to control the adhered state.

<Means for Solving the Problems> The present invention provides a method for producing a synthetic resin molding material that solves the above-mentioned conventional problems. The method is a method of forming an unsaturated polyester resin on two films such as polyethylene. , To which a compound consisting of a filler, a curing agent, a thickener, etc. is applied, and a chopped strand obtained by cutting the glass roving into a required length by a roll cutter is sprayed,
In a method for producing a synthetic resin molding material in which a chopped strand and a compound are impregnated by pressing with a roll while sandwiching with the two films, the glass roving is moved in a compound tank before the glass roving is transferred to the cutter roll. Passing through to impregnate the glass roving with a compound in advance, removing the excess compound with a roll from the glass roving impregnated with the compound in advance, and cooling and solidifying the glass roving from which the excess compound has been removed with a cooler It is characterized in that it is subjected to a pretreatment with the step of performing.

<Operation> According to the method of the present invention, the glass roving before being cut with the cutter roll is passed through the compound tank to impregnate the glass roving with the compound in advance, and the excess compound is removed by the roll. It is possible to manage the impregnation state by firmly and evenly adhering to the roving and cooling and solidifying with a cooler.
Moreover, cutting with a cutter roll can be easily performed.

The chopped strands that have been subjected to the above-described pretreatment have good "wettability" with the compound between the films, and the air mixed during impregnation flows to a site unrelated to the pinholes. Further, the exposure of the glass fiber not covered with the resin on the surface of the molded product and the curling phenomenon are eliminated.

<Example> An example of the present invention will be described below with reference to FIG. 1,
2 is a film made of polyethylene or the like, 4 is the film 1,
The compound to be applied to 2 is a belt conveyor, 6 is a chopped strand cut by a cutter roll 9 to a required length, 7 is a roll, 8 is a synthetic resin molding material, that is, a sheet material, and the cutter roll 9 and later are conventional. It is the same as the manufacturing method of.

The present invention is characterized in that, in the above manufacturing method, the glass roving 3 before being cut by the cutter roll 9 is impregnated with a compound in advance and subjected to a pretreatment for cooling and solidifying.

As a specific example of this pretreatment, the glass roving 3 is passed through the compound tank 10, and the impregnating roll 11 surely impregnates the compound into the glass roving 3 to take it out of the compound tank 10. Remove the compound.

The compound-impregnated glass roving 3a passing through the roll 12 is cooled and solidified by the cooler 13, and the cooled and solidified glass roving 3b is transferred to the cutter roll 9.

In the method of the present invention, the glass roving 3 is passed through the compound tank 10 to impregnate the glass roving 3 with the compound in advance, and the excess compound is rolled into a roll 1.
The compound is glass roving 3 to remove in 2
It adheres evenly to all.

The impregnated state of the compound-impregnated glass roving 3a that has passed through the roll 12 can be controlled in the glass roving 3b that has passed through the cooler 13 and has been cooled and solidified, and the cutting with the cutter roll 9 becomes easy.

Further, by impregnating the glass roving 3 with a compound in advance, the above conventional problems can be solved.

That is, since the chopped strands 6 are coated with the compound, as shown in FIG. 2 (A), the air a2 apparently mixed during the impregnation is entangled with the chopped strands 6 at the initial stage of the impregnation, but the chopped strands 6 are As shown in Fig. 2 (B), the "wettability" between the compound 4 and the compound 4 is good. After a certain period of time (the compound that has been solidified by cooling is remelted) The behavior of the air a1 mixed in is shown.

Further, since the compound and the hardly soluble binder resin can be used, neither the exposure of the glass fiber not covered with the resin nor the curling phenomenon occurs on the surface of the molded product.

<Effects of the Invention> As described above, according to the method of the present invention, the glass roving before being cut with the cutter roll is passed through the compound bath to impregnate the glass roving with the compound in advance, and the excess compound is removed by the roll, By performing a pretreatment for cooling and solidifying with a cooler, the compound will adhere to the glass roving uniformly and uniformly, the compound impregnation state of the glass roving can be directly controlled, and cutting with a cutter roll will be easy. Therefore, it is possible to prevent the fluctuation of the impregnation state in the manufacturing process, the impregnation failure and the cutting failure, and the quality can be stabilized.
Reduces pinholes after painting due to burrows caused by poor impregnation of chopped strands and compound that cut glass roving, which is a fiber reinforcement, and eliminates sink marks and swells on the surface of molded products. A synthetic resin molding material capable of obtaining a good molded product is manufactured.

[Brief description of drawings]

FIG. 1 is an embodiment diagram showing the method of the present invention. FIG. 2 is an explanatory view of the behavior of air mixed during impregnation of a synthetic resin molding material manufactured by the method of the present invention, FIG. 3 is an explanatory view of a conventional method, and FIG. 4 is a synthetic resin molding material manufactured by the conventional method. It is explanatory drawing which shows the air mixed at the time of impregnation. 1, 2 ... Film, 3 ... Glass roving, 4 ...
Compound, 6 ... Chopped strands, 10 ...
Compound tank, 13 ... Cooler.

Claims (1)

[Claims] 1. A glass roving cut into a desired length by a roll cutter, which is obtained by applying a compound consisting of an unsaturated polyester resin, a filler, a curing agent, a thickener, etc. to two films of polyethylene or the like. In a method for producing a synthetic resin molding material, in which chopped strands are dispersed, and while being sandwiched by the two films, pressed by a roll to impregnate the chopped strands and the compound, before the glass roving is transferred to the cutter roll, A step of impregnating the glass roving with the compound in advance by passing through a compound tank, a step of removing the excess compound by a roll of the glass roving impregnated with the compound in advance, and a glass roving with the excess compound removed By the cooler Method for producing a synthetic resin molded timber, characterized in that pretreated with a step of cooling and solidifying.