JPH06304942A - Production of deep draw press molded product - Google Patents

Abstract

PURPOSE:To efficiently produce a deep draw press molded product excellent in the surface gloss or smoothness in its rising surface in large quantities from a thermosetting resin compsn. by a thermal press molding method. CONSTITUTION:When a thermosetting resin compsn. is supplied to a mold consisting of upper and lower molds to produce a molded product having a deep draw shape by thermal press molding, the mold is vibrated within a time range of Tv represented by formula Tk+(Tp-Tk)/2>=Tv>=Tp+(Tp-Tk) (wherein Tk is the time up to a kick-off point starting the sudden generation of curing heat of the thermosetting resin compsn. from a point of time when the thermosetting resin compsn. comes into contact with both surfaces of the upper and lower molds and Tp is the time up to the max. generation of heat) from the point of time when the thermosetting resin compsn. comes into contact with the surfaces of the upper and lower molds in a thermal press molding process.

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 deep-draw press-formed product.

[0002]

2. Description of the Related Art A thermosetting resin is used as a matrix resin,
Sheet molding compound (SMC) or bulk molding is used as a method for manufacturing a large amount of molded products at a relatively low cost using a thermosetting resin composition including a filler, an aggregate, a curing catalyst, an internal mold release agent, and a pigment. A method of hot press molding a molding material such as a compound (BMC) can be mentioned.

By the hot press molding method of the above molding material,
When molding a molded product with a rising surface such as a bathtub, the rising surface is deformed due to molding shrinkage during curing, etc., and minute irregularities are generated on the surface, so the molding material and the mold surface do not contact sufficiently. , Because not enough pressure is applied,
There was a problem that the rising surface had poor smoothness and poor gloss. This tendency becomes remarkable especially in the case of a thick molded product.

As a countermeasure against this, a method of adding a large amount of a low-shrinking agent to a molding material to reduce the molding shrinkage has been carried out. However, the thermal expansion of the low-shrinking agent is higher than that of the thermosetting resin. However, there is a problem in that the thermosetting resin and the mold surface do not come into sufficient contact with each other and only a molded product having a poor appearance can be obtained.

Further, in order to obtain a molded product having a good appearance,
Japanese Patent Laid-Open No. 3-24919 discloses a molding method using a vibration press machine. However, vibration causes a surface friction between the mold surface and the molded product, so that the surface smoothness of the rising surface of the molded product is obtained. There was a problem that it was difficult to be done.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to obtain a thermosetting material having excellent surface smoothness and gloss on the rising surface by a hot press molding method. It is an object of the present invention to provide a method for efficiently producing a deep-drawing press-formed product of a water-soluble resin composition in a large amount.

[0007]

The thermosetting resin composition used in the present invention comprises a thermosetting resin and a reinforcing material.

Examples of the thermosetting resin include conventionally known resins such as unsaturated polyester resin and vinyl ester resin.

The unsaturated polyester resin is preferably one in which an unsaturated polyester obtained by reacting an acid component and a polyhydric alcohol component is dissolved in a polymerizable monomer. Examples of the acid component include α, β-unsaturated dibasic acids and anhydrides thereof, and these may be used alone or in combination of two or more.

Examples of the α, β-unsaturated dibasic acid include maleic acid, fumaric acid, itaconic acid, ditraconic acid and chloromaleic acid, which may be used alone or in combination of two kinds. The above may be used in combination.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, neopentyl glycol, 1,6-hexanediol, triethylene glycol, hydrogenated bisphenol A. , Isopentyl glycol, glycerin, trimethylolpropane, dicyclopentadiene and the like.

At least one kind of saturated dibasic acid and its anhydride may be added to the above acid component, if necessary.

Examples of the saturated dibasic acid include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid,
Succinic acid, azelaic acid, adipic acid, tetrahydrophthalic acid, hexahydrophthalic acid, chlorendic acid,
Examples thereof include tetrachlorophthalic acid and tetrabromophthalic acid.

Examples of the polymerizable monomer include styrene, vinyltoluene, divinylbenzene, α-methylstyrene, chlorostyrene, dichlorostyrene, vinyl acetate, diallyl phthalate, diallyl isophthalate,
Examples thereof include vinyl monomers and vinyl oligomers that can be crosslinked with unsaturated polyesters such as diallyl terephthalate, but styrene is generally used.

The above-mentioned vinyl ester resin has a vinyl group at the terminal of the ester chain or ether chain, and generally includes epoxy acrylate.

In the unsaturated polyester resin, if the amount of unsaturated polyester is small, a molded product having sufficient strength cannot be obtained, and if it is large, moldability and workability are deteriorated. Therefore, 100 parts by weight of unsaturated polyester resin is used. During,
It is preferable that 50 to 20 parts by weight of the polymerizable polyester is mixed with 50 to 80 parts by weight of the unsaturated polyester.

Examples of the reinforcing material include glass fibers; synthetic fibers such as polyester, phenol and vinylon; carbon fibers and the like, but glass fibers are generally used. The amount of the reinforcing material added is appropriately determined in consideration of the strength and viscosity of the molded product.

If necessary, conventionally known curing catalysts, fillers, low-shrinking agents, internal mold release agents, thickeners, reinforcing materials, pigments and the like are appropriately added to the thermosetting resin composition. May be.

Examples of the curing catalyst used for the above unsaturated polyester resin include t-butylperoxybenzoate, benzoyl peroxide, methyl ethyl ketone peroxide, t-butyl peroxyisopropyl carbonate and t-butyl peroxy-2-ethyl. Examples thereof include organic peroxides such as hexanoate and 1,1-di-t-butylperoxycyclohexanone.

The amount of the above curing catalyst is preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin.

Examples of the above-mentioned filler include calcium carbonate, magnesium carbonate, barium sulfate, talc, clay, mica, silica, alumina, glass powder, aluminum hydroxide, magnesium hydroxide, cold water stone, silica sand, crushed resin pieces, Examples thereof include gel-coated chips. In particular, aluminum hydroxide is preferable in order to obtain a transparent feeling upon curing.

The amount of the above-mentioned filler to be added is generally determined in consideration of economical efficiency, workability, strength of the molded product, etc., but it is preferable that the amount be a close packing.

Examples of the low-shrinking agent include thermoplastic resins such as polyethylene, polystyrene, polymethylmethacrylate, polyvinyl chloride, polyvinyl acetate, polycaprolactam and saturated polyester; polybutadiene rubber;
A polystyrene-acrylonitrile copolymer is mentioned.

Examples of the internal release agent include stearic acid, zinc stearate, stearic acid ester, alkyl phosphoric acid ester and the like. The amount of the internal release agent added is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin.

Examples of the above-mentioned thickening agent include unsaturated polyester resins which chemically bond with the hydroxyl group, carboxyl group and ester bond of the unsaturated polyester to form a linear or partial crosslinkage to increase the molecular weight. For example, diisocyanates such as toluylene diisocyanate; metal alkoxides such as aluminum isopropoxide and titanium tetrabutoxide; oxidation of divalent metals such as magnesium oxide, calcium oxide and beryllium oxide. Substances: Divalent metal hydroxides such as calcium hydroxide can be mentioned.

The amount of the thickener added is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin.

The pigment is not particularly limited as long as it does not significantly impair the curability of the thermosetting resin.

The thermosetting resin composition is kneaded using a kneader such as a conventionally known mortar mixer or kneader to obtain a bulk molding compound (BM).
It can be easily prepared into a molding material such as C) or sheet molding compound (SMC).

In order to prevent the volatile components from evaporating from the thermosetting resin composition, the thermosetting resin composition is wrapped in polyethylene laminated cellophane or the like and thickened by aging at room temperature or by heating. Due to this thickening, the thermosetting resin composition has a relatively hard clay-like shape and can be stably stored as a lump or a plate in a cool dark place for a long period of time.

The above-mentioned thickening method is 2 at room temperature.
It is enough to stand for 4 to 72 hours, and when heated, a temperature at which the life of the thermosetting resin composition is not impaired, for example,
Examples include aging at 35 to 60 ° C.

In the present invention, when the thermosetting resin composition is supplied to a deep drawing die consisting of an upper die and a lower die for hot press molding, the die is vibrated for a certain period of time. The conditions for the above heat press molding are a temperature of 90 to 170 ° C. and a pressure of 10 to 150 kgf / cm with respect to the projected area of the molded product.
² is preferred.

In the above heat press molding, if the time at which the mold is vibrated is too early, the thermosetting resin composition will be insufficiently cured, and if it is too late, the thermosetting resin composition will be completely cured. In any case, since the effect of the present invention cannot be obtained, the time range for vibrating the mold is represented by the following formula T
It is represented by v.

Tk + (Tp−Tk) / 2 ≦ Tv ≦ Tp + (Tp−Tk)

In the formula, Tk represents the time from the time when the thermosetting resin composition comes into contact with both surfaces of the upper mold and the lower mold to the kick-off point at which the resin composition suddenly starts heat generation for curing. , Tp represents the time until the maximum heat generation starts from the time when the resin composition contacts both surfaces of the upper mold and the lower mold.

Within the time range of Tv, the thermosetting resin composition is cured to become a semi-cured or almost completely cured state, but since the fluidity is maintained, the mold is vibrated while being vibrated. By heat press molding, the thermosetting resin composition and the mold are brought into contact with each other, and a molded article having a good appearance and gloss can be obtained.

Vibration of the mold is preferably in the three-dimensional directions of up, down, left and right. As a method of vibrating the mold, for example, a mechanical system such as a cam crank system or an unbalanced ewet system; an electrodynamic exciter. Electromagnetic type electric system such as electro-hydraulic system.

It is preferable that the kick-off point of the above-mentioned thermosetting resin composition and the time until it exhibits the maximum heat generation are measured in advance by a temperature sensor.

[0038]

EXAMPLES Examples of the present invention will be described below. (Examples 1 to 3, Comparative Examples 1 to 5) Unsaturated polyester component consisting of fumaric acid, isophthalic acid and propylene glycol, and 100 parts by weight of unsaturated polyester resin containing styrene monomer and polystyrene as polymerizable monomers, A thermosetting resin composition containing 1 part by weight of magnesium oxide, 1 part by weight of a curing agent of t-butylperoxybenzoate, 5 parts by weight of zinc stearate and 200 parts by weight of aluminum hydroxide was mixed with 1/2 inch chopped glass fiber 34.
A part by weight was impregnated and aged at 40 ° C. for 24 hours to obtain a sheet molding compound (SMC).

Using the above SMC, a vibration press machine (“vibration press machine SA-50” manufactured by Asahi Engineering Co., Ltd.,
50 tons), and a vibration was performed at a frequency of 750 Hz and an amplitude of 10 μm to form a deep-drawing molded product (thickness 6 mm × 200 × 150 × depth 100 mm) under the molding conditions shown in Table 1. Mold temperature was set to 125 ° C. for the upper mold and 140 ° C. for the lower mold for molding for 6 minutes. In Table 1, Ta is the time from when the SMC contacts both surfaces of the upper mold and the lower mold until the vibration starts,
Tb indicates the time until the vibration is stopped. Further, when the Tk and Tp of the SMC were measured in advance, they were 120 seconds and 180 seconds, respectively.
The calculation of v is as follows. Tk + (Tp−Tk) / 2 = 150 ≦ Tv ≦ Tp + (Tp−Tk) = 240

The surface state (presence or absence of cloudiness, etc.) of the rising surface of the obtained molded product was visually evaluated, and a 60-degree specular gloss was measured as the gloss, and the results are shown in Table 1.

[0041]

[Table 1]

[0042]

The structure of the method for producing a deep-drawing press-formed product according to the present invention is as described above. By vibrating the die for a certain period of time in the hot press-forming method, the surface gloss and smoothness of the rising surface are increased. Since a deep-drawing press-formed product of the excellent thermosetting resin composition can be efficiently produced in a large amount, it is preferably used for producing FRP wall materials, table tops, bathtubs, and vanities.

Claims (1)

[Claims] 1. When a thermosetting resin composition is supplied to a mold composed of an upper mold and a lower mold to hot press-mold a molded product having a deep drawing shape, the following formula is used in the hot pressing process. Done T
A method of manufacturing a deep-drawing press-formed product, which comprises vibrating a mold within a time range of v. Tk + (Tp−Tk) / 2 ≦ Tv ≦ Tp + (Tp−Tk) (In the formula, Tk is a thermosetting resin starting from the time when the thermosetting resin composition contacts both surfaces of the upper mold and the lower mold. The time to the kick-off point at which the composition suddenly begins to generate heat of curing, T
(p indicates the time to maximum fever, respectively)