JPS62117731A - Manufacture of resin molded product - Google Patents

Abstract

PURPOSE:To prevent the internal defect and residual stress from developing in a product and enhance the strength of the product by a method wherein a thermosetting resin laminated body, in the respective laminate locating in the inner layer part of which magnetic powder is added and dispersed, is pre- heated by being applied by high-frequency magnetic field. CONSTITUTION:The required amount of magnetic powder is added and uniformly dispersed in thin resin sheets 12. When high-frequency magnetic field is applied to a resin laminated body 10 installed in a high-frequency induction heating device, magnetic metal powder generates heat due to eddy current loss and the resin laminated body 10 is heated in the order of several minutes up to the target temperature for pre-heating. Because a mold is clamped under the state that the resin laminated body 10 which is pre-heated even to the inner layer part is set in said split mold for pressingly heating, the resin laminated body is cured with a small difference between the curing speed in the outer layer part and that in the inner layer part of the resin laminated body. Consequently, high strength molded product with neither internal defect nor residual stress such as outer plate and wheel for automobile is obtained.

Description

[Detailed description of the invention]

The present invention relates to a method for forming articles by heating and compression molding a thermosetting resin laminate.

[Image resin made of thermosetting resins such as unsaturated polynisal resins, vinyl ester resins, epoxy resins, phenol resins, and silicone resins reinforced with fibers such as glass fibers and hydrocarbon fibers, 1. Used for manufacturing various rod products such as corrugated plates, flat plates, bathtubs, septic tanks, JN boats, and automobile parts. In order to obtain such articles, sheet-shaped resin molding material (SH
C: 5heet molding c. mpound) is preferably used. 5) Ic
JJ usually refers to a forming material in which glass JAIi navy blue is impregnated with a resin mixture containing a chemically thickened unsaturated polyester resin as a heavy phase. Teso JT: Cotton molding is performed. For example, to form a thick plate using SHC, stack a large number of SHC sheets (for example, 10 sheets or more) and set them in a heating and pressing mold 1. Tighten the mold below L1, The resin laminate is pressurized and heated to harden. However, the resin laminate is preheated before it is placed in the mold and covered, to shorten the molding time using the mold, but the resin laminate is When the meat II7 of the h1 layer becomes large, a large temperature difference occurs between the outer layer and the inner layer, which are heated in contact with the inner wall of the mold, due to the shape set in the mold. Since the inner layer hardens more slowly than the inner layer, when pressure is applied during final tightening, the flow characteristics of the resin in the inner and outer layers change, causing internal cracks, cavities, and reinforcing fibers. This causes problems such as disturbance of the temperature and the generation of residual stress (thermal stress).As a countermeasure, 1) adjust the time from preheating the resin laminate to setting it in the mold, 2) increase the mold temperature. Various methods have been adopted, such as adjusting the mold clamping time and adjusting the mold clamping time, but none of them have been able to solve the problem.On the other hand, surrounding heating of the resin fili layer has been Alternatively, it is possible to use infrared rays over a long period of time to raise the temperature of the inner layer sufficiently, but the outer layer will begin to harden during that time, and this will not solve the problem at all. Another object of the present invention is to rapidly uniformly heat a resin laminate.
The aim is to obtain a resin molded article without any defects. In a method of manufacturing an article by heating and compression molding a thermosetting resin laminate, a thermosetting Gl resin laminate comprising magnetic powder added and dispersed in each of the enclosures located in at least six inner layers is subjected to high frequency induction. Insert it into the heating device? :H-frequency magnetic field is applied to perform preheating, and the preheated thermosetting resin molded body is placed in a heating and pressing mold for compression molding). If magnetic powder is added and uniformly dispersed in a thermosetting resin as a raw material for obtaining resin moldings, and a high frequency magnetic field is applied to it, eddy currents will be generated in the magnetic powder in the resin.
The generated heat uniformly and quickly heats the resin without any difference between the inner and outer layers. The reason why this method allows the resin to be heated quickly is that when heat is applied from the outside, it takes a long time for the resin temperature in the inner layer to rise, but the magnetic powder dispersed in the resin This is because the entire resin layer is heated directly and uniformly. As this magnetic powder, a ferromagnetic total bending powder such as Fc, Nλ, and Co, or a powder of a metal compound (electrical resistivity = 10-5 to 104 Ω・m) such as a metal oxide or a metal sulfide is used. Considering the preheating temperature of the thermosetting resin (approximately 100° C.), it is preferable to use the latter, that is, a powder of a metal compound. In addition, the particle size of the magnetic powder is different from the normally used filler I14 material (
For example, the same level as that of calcium carbonate), i.e. 1 to 2
It is preferable that the amount is 5 to 30 μm, and the amount of addition is determined by the target heating temperature and the amount of water used in the high-frequency induction heating device, but it is preferably 5 to 30 percent. The reason why this range of addition rate is preferable is that at less than 5% by weight,
It is not possible to obtain a heating rate that allows the temperature to rise to the target temperature in a few minutes, resulting in poor productivity.If the heating rate exceeds 30,000%, the physical properties of the resin (the resin that turns the magnetic powder into gold) will change significantly, resulting in problems in molding.
Or it is because it is unfavorable for the strength of the product. Note that the method of the present invention is not limited to the molding of fibers@reinforced resins, but can also be applied to molding of thermosetting resins that do not contain reinforcing fibers. Dog JLJ Hereinafter, the present invention will be explained with reference to specific examples shown in FIGS. 1 and 2. The resin laminate 10 has a thin plate 12 similar to SHC sheets 1 to 1.
A required amount of magnetic powder is added and uniformly dispersed in the thin resin plate 12. When the resin laminate 10 is placed in a high-frequency induction heating device equipped with an induction coil 14 and an 8-frequency magnetic field is applied, Ia
The bamboo metal powder generates heat due to eddy current loss, and the resin laminate 10 reaches the preheating target temperature in about a few minutes. By setting the resin laminate 10, which has been sufficiently preheated up to the inner layer part, in a split mold for heating and pressurizing and clamping the mold, the resin laminate 10 is cured with a small difference in the curing speed between the outer layer part and the inner layer part. , high-strength molded articles (e.g., automobile outer panels, small automobile wheels) with no internal defects or residual stress (thermal stress) are classified as I+.
′? can be done. In addition, the preheated resin I? When a 1-layer body is placed in the mold, the temperature of the outer layer in contact with the inner wall of the mold hole rises, so the preheating temperature is lowered in the outer layer and J'3 is heated. For example, if the i9 thick resin plate 123 to which magnetic powder is added is used for the inner layer and the thin resin plate 12A to which no magnetic powder is added is used for the outer layer, the outer layer can be heated by preheating with a high-frequency induction heating device. It is possible to provide a resin laminate in which the temperature of the inner layer portion is higher than that of the inner layer portion. In addition, if you want to perform preheating such that the temperature gradually increases from the outer layer toward the inner layer, the outer layer resin laminate 1
0 and the addition of magnetic powder to the inner layer resin laminate 10 may be gradually changed. As is clear from the above explanation, in the method of manufacturing articles by heating and compression molding a thermosetting resin laminate, magnetic powder is added and dispersed at least to each diseased body located in the inner layer. The thermosetting resin laminate is placed in a high-frequency induction heating device, preheated by applying a high-frequency magnetic field, and the preheated thermosetting resin molded body is placed in a heating and pressing mold. A method of manufacturing a resin molded article has been proposed, which is characterized by compression molding. According to this method, it is possible to obtain a resin laminate that is sufficiently uniformly preheated to the inner layer. There is little difference in curing speed, internal defects, residual stress (thermal stress)
A molded article with high strength can be obtained. In addition, by adding and dispersing magnetic powder into the resin laminate and heating it using high frequency reading, it is possible to raise the temperature to the preheating target temperature in a short time, which improves productivity. In addition to the intended effect, it is possible to prevent the progress of hardening during the preheating treatment, and it is possible to first detect an adverse effect on the subsequent pressure molding.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing a pre-heat treatment mode of a resin laminate according to the method of the present invention, and FIG. 2 is an exploded perspective view showing another example of a resin laminate. 10...Resin Laminated body, 12... Thin resin plate, 14.
...Induction coil.

Claims (1)

[Claims] In a method of manufacturing an article by heating and compression molding a thermosetting resin laminate, a thermosetting resin laminate in which magnetic powder is added and dispersed in each layer located at least in the inner layer portion is placed in a high-frequency induction heating device. Production of a resin molded product, characterized in that the preheated thermosetting resin molded product is charged, preheated by applying a high-frequency magnetic field, and the preheated thermosetting resin molded product is placed in a heating and pressing mold for compression molding. Method.