JPH07237232A - Method for producing thermosetting resin irregularly shaped product - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for producing a thermosetting resin shaped article having a high productivity, a beautiful and deep flow pattern. [Structure] After supplying BMC2 onto the mold surface of a lower mold 11, the movable mold 12 is moved downward, air in the cavity 13 is sucked through a pressure reducing passage 117 to close the mold under reduced pressure. At this time, the movable die 12 was brought into contact with a part of the BMC 2, and styrene vapor bubbles were generated at the tip portion 21 of the BMC 2 not yet in contact with the movable die 12, and then the die was completely closed and added. Press forming.

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 irregularly shaped product having a high productivity, a beautiful and deep flow pattern.

[0002]

2. Description of the Related Art A resin composition prepared by adding a filler, a curing agent, a release agent, a pigment, a thickener, etc. to an unsaturated polyester resin is impregnated into reinforcing fibers such as glass fibers to obtain a bulk or sheet. The molding material is shaped into a bulk sheet molding compound (hereinafter referred to as BMC) and a sheet / sheet molding compound (hereinafter referred to as S).
MC) etc., and is mainly compression molded,
It is used as a bathroom counter, kitchen counter, table, etc.

However, recently, a so-called patterned product having a marble-like, stone-grained, or granite-like pattern imitating natural stone is preferred. And, for example, Japanese Patent Publication Sho 57
As described in Japanese Patent No. 21448, two resin compositions having different compositions are agitated so that a desired marble pattern is drawn, and the mixture is thickened at room temperature or by heating until it becomes a relatively hard clay-like material. , A method of manufacturing an artificial marble product in which the molding material is charged into a mold and heated and pressed to be cured has been proposed.

[0004]

However, the marble products obtained by this method have the drawbacks that they have no texture and a poor sense of depth as compared with natural marble. In addition, it is necessary to mix the two resin compositions in advance in order to obtain the molding material.

The present invention provides a method for producing a thermosetting resin irregularly shaped product having a flow pattern with a beautiful and deep feeling, which does not require any labor for preparing BMC which is a molding material. It was done for the purpose.

[0006]

SUMMARY OF THE INVENTION The present invention provides a bulk molding compound composed of an unsaturated polyester resin containing a copolymerizable monomer, a reinforcing material, and an inorganic filler, and a movable mold and a movable mold. A method for producing a thermosetting resin profiled molded article, which comprises supplying the material to a mold made of a mold and closing the mold to perform pressure molding, wherein the compound is supplied to the fixed mold,
When the movable mold is moved to close the mold under reduced pressure, the movable mold is brought into contact with at least a part of the compound to form a surface of a molded article of the compound which is not yet in contact with the movable mold. Is a method for producing a thermosetting resin irregularly shaped product in which the mold is completely closed after vapor bubbles of the copolymerizable monomer are generated in the area where

In the present invention, the unsaturated polyester resin is a mixture of an unsaturated polyester obtained by polycondensing an unsaturated dibasic acid, a glycol and optionally a saturated dibasic acid, and a copolymerizable monomer. Is. As the resin component contained in the unsaturated polyester resin, in addition to the unsaturated polyester, a thermoplastic resin added for reducing the shrinkage can be mentioned.

As the unsaturated dibasic acid, for example, maleic anhydride, fumaric acid, itaconic acid, citraconic acid and the like are used. Examples of the glycol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butanediol,
1,4-butanediol, 1,6-hexanediol,
Bisphenol A, hydrogenated bisphenol A, ethylene oxide adduct of bisphenol A, neopentyl glycol and the like are used.

As the saturated dibasic acid, phthalic anhydride, orthophthalic acid, isophthalic acid, terephthalic acid, adipic acid, succinic acid, tetrachlorophthalic acid, het acid and the like are used. As the copolymerizable monomer, styrene, dichlorostyrene, vinyltoluene, vinyl acetate, methacrylic acid ester, acrylic acid, acrylic acid ester, diacrylic phthalate and the like are used, but styrene is preferably used.

Usually, the amount of the copolymerizable monomer contained in the unsaturated polyester resin is preferably 20 to 50% by weight. Examples of the thermoplastic resin for reducing shrinkage include, for example,
Polystyrene, polyvinyl acetate, polymethyl methacrylate, polyethylene, poly ε-caprolactone, saturated polyester, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, acrylonitrile-styrene copolymer and the like are used.

Examples of the inorganic filler include glass powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, barium sulfate, talc,
Clay, mica, silica, alumina, cryolite, silica sand, etc. are used. These inorganic fillers may be added alone or in combination of two or more. The addition amount of the inorganic filler is preferably in the range of 50 to 360 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin. The particle size of the inorganic filler is preferably 1 to 30 μm.

As the reinforcing material, fibrous materials are effective. For example, glass fibers, organic fibers such as polyester, phenol and vinylon, carbon fibers and the like are used. Generally, glass fibers are used. To be done.

The length of the reinforcing material is preferably 1 to 80 mm.
If the length is shorter than 1 mm, there is no reinforcing effect, and conversely 80 m
If it is longer than m, the viscosity increases and the moldability deteriorates. In particular,
For artificial marble, it is preferably 1 to 20 mm.
2 to 15 mm is more preferable. If the length is shorter than 1 mm, there is no reinforcing effect, and conversely, if the length is longer than 20 mm, the appearance of the molded product is impaired. For example, in the case of glass fiber, a chopped strand obtained by cutting the strand into a certain length, a chopped strand mat in which the chopped strand is adhered to form a mat, and the like are used.

The amount of the glass fiber added is 1 to the total amount of BMC.
A range of 40% by weight is preferred. If the amount added is less than 1% by weight, there is no reinforcing effect, and conversely, if the amount added is more than 40% by weight, the viscosity increases and the moldability deteriorates. Particularly for artificial marble, the addition amount is preferably 1 to 20% by weight, more preferably 3 to 15% by weight. If the added amount is less than 1% by weight, there is no reinforcing effect, and if the added amount is more than 20% by weight, the transparency is significantly reduced.

Examples of the curing agent include t-butylperoxybenzoate, benzoylperoxide, methyl ethyl ketone peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-di-t. Known organic peroxides such as butyl peroxycyclohexane and t-peroxy isopropyl carbonate are used as curing agents for thermosetting resins.

Examples of the internal release agent include higher fatty acids and higher fatty acid salts such as stearic acid and zinc stearate,
An alkyl phosphate ester or the like is used.

The thickener is chemically bonded to a hydroxyl group, a carboxyl group, an ester group or the like of the unsaturated polyester resin to cause linear or partial cross-linking to increase the molecular weight and increase the unsaturated polyester resin. A viscous substance, for example, diisocyanates such as toluene diisocyanate, metal alkoxides such as aluminum isopropoxide and titanium tetrabutoxide, divalent metal oxides such as magnesium oxide, calcium oxide and bryllium oxide, and calcium hydroxide. Such a divalent metal hydroxide is used.

A resin composition obtained by adding a reinforcing material and an inorganic filler to an unsaturated polyester resin is usually used as a curing agent, an internal release agent, a thickener, and if necessary, an antioxidant, a curing accelerator, and a polymerization agent. Add inhibitors, pigments, and low-shrinking agents, mix and knead them with a Henschel mixer, and then integrate them into a bulk form, cover with a release film such as polyethylene film to prevent volatilization of volatile components of the resin composition, and age. However, usually, by placing the material under a temperature condition of 30 to 50 ° C. for half a day to 2 days, the viscosity is increased to 1,000,000 poise or more, and it is semi-solidified.
And

In the present invention, the movable mold is brought into contact with at least a part of the BMC under reduced pressure, and as shown in the figure later,
A mold is closed in a state where vapor bubbles of the copolymerizable monomer are generated in the portion of the BMC that is not yet in contact with the movable mold.

The conditions for generating vapor bubbles of a copolymerizable monomer typified by styrene depend on the half-life temperature of the curing agent, but usually the degree of reduced pressure is -100 to -760 mm.
Hg and the mold temperature are preferably in the range of 100 to 160 ° C. The amount of bubbles generated is the degree of pressure reduction, the moving speed of the movable type,
It can be adjusted by changing the heating temperature of the mold.

Such bubbles are obtained by flowing into the mold when the mold is closed and staying in the stagnation parts such as the flow end and the bent part so that the mold is completely closed and pressure-molded. It appears as a flow pattern at the flow end or bend of the molded product.

The method for producing the thermosetting resin irregularly shaped product of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a mold used in a method for manufacturing a minibus (thermosetting resin shaped article) as an example of the present invention, FIGS. 2 to 4 are cross-sectional views for explaining the manufacturing process, and FIG. It is a perspective view which shows the minibus obtained by. As shown in FIG. 1, the mold 1 includes a lower mold (fixed mold) 11 and an upper mold (movable mold) 12.

The lower mold 11 has a bottom wall outer surface forming portion 111, a side wall outer surface forming portion 112, a flange lower surface forming portion 113, a lower wall inner surface forming portion 114, and a lower wall lower surface forming portion of the minibus to be molded. 115 and a step portion 116 are formed. Further, a decompression passage 117 is formed from the step portion 116 to the outside of the mold.

The upper die 12 has a bottom wall inner surface forming portion 121, a side wall inner surface forming portion 122, a flange upper surface forming portion 123, a lower wall outer surface forming portion 124, and a step portion 125 of the minibus to be molded. Has been done.

Then, between the mold surfaces of the lower mold 11 and the upper mold 12,
When the mold is closed, a cavity 13 having an inner shape corresponding to the outer shape of the minibus to be molded is formed. Also, the lower mold 11
O between the outer surface of the upper part of the mold and the side surface of the step 125 of the upper mold 12.
─ Close the mold with the ring 14 in between,
By sucking air from the pressure reducing path 117, the pressure inside the cavity 13 can be reduced until the mold 1 is completely closed.

First, as shown in FIG. 2, the lower mold 11 and the upper mold 12 are heated and the upper mold 12 is raised. After the BMC 2 is supplied onto the mold surface of the lower mold 11, the upper mold 12 is heated. 12 is moved down onto the lower mold 11 at a constant moving speed.
At this time, at the sealing position where the O-ring 14 is interposed between the upper outer surface of the lower die 11 and the side surface of the step 125 of the upper die 12, the lowering movement of the upper die 12 is temporarily stopped to reduce the pressure. By sucking air from the passage 117 with a vacuum pump (not shown), the inside of the cavity 13 is depressurized and the vacuum pump is stopped.

Then, as shown in FIG. 3, the bottom wall inner surface forming portion 121 and the side wall inner surface forming portion 122 of the upper mold 12 are again formed by BM.
BM which is in contact with a part of C but not in contact with the movable type
Tip portion 2 of C2 that will form the surface of the molded product
1 and the like are in a state where vapor bubbles of the copolymerizable monomer are generated. Subsequently, the upper mold 12 is moved down onto the lower mold 11, the mold is completely closed as shown in FIG. 4, and pressure molding is performed for a predetermined time at a constant molding pressure by a press machine (not shown). As shown in FIG. 5, a minibus 3 having a flow pattern 31 at the flow end or the bend is obtained.

[0028]

The method for producing a thermosetting resin irregularly shaped product of the present invention comprises: an unsaturated polyester resin containing a copolymerizable monomer;
Manufacturing method of thermosetting resin shaped article in which bulk molding compound composed of reinforcing material and inorganic filler is supplied into a mold consisting of a fixed mold and a movable mold in a heated state, and the mold is closed to perform pressure molding That is, after supplying the compound into the fixed mold, when moving the movable mold to close the mold under reduced pressure, the movable mold is brought into contact with at least a part of the compound and is still in contact with the movable mold. Not in the above compound, the mold is completely closed after the vapor bubbles of the copolymerizable monomer are generated in the part that will form the surface of the molded product, so that the flow end or the bent part, etc. It is possible to obtain a thermoset resin shaped article having a beautiful and deep flow pattern.

The reason for this is not clear yet,
In a state where vapor bubbles are generated in the BMC at the portion where the copolymerizable monomer in BMC forms the surface of the molded article,
Together with the fact that it is under a reduced pressure, it is presumed that that part initiates the curing reaction very slightly earlier than other parts and contributes to the development of the flow pattern.

[0030]

EXAMPLES The present invention will be described below with reference to examples. Examples 1 to 4 100 parts by weight of unsaturated polyester resin, 125 parts by weight of glass powder (average particle size 20 μm), 125 parts by weight of aluminum hydroxide (average particle size 15 μm), 13 parts by weight of glass fiber (length 1.5 mm) , Curing agent (tertiary butyl peroxybenzoate) 1 part by weight, internal release agent (zinc stearate) 3 parts by weight, thickener (magnesium oxide) 1
After weighing parts by weight, these are mixed and kneaded with a Henschel mixer, wrapped with polyethylene laminated cellophane,
BMC was prepared by aging and thickening at 40 ° C. for 40 hours.

As shown in FIG. 1, the temperature of the lower mold 11 was 105 ° C. and the temperature of the upper mold 12 was 13 kg.
It is supplied to the mold surface of the lower mold 11 of the mold 1 heated to 0 ° C.
~ According to the process described with reference to Fig. 4, the minibus was pressure-molded to obtain the minibus as shown in Fig. 5.

In the pressure molding, the molding pressure is 100 kg / m.
It was performed by pressurizing with a 300 ton press at m ^{2 for} 12 minutes. Further, the moving speed (pressurizing speed) and the degree of pressure reduction of the upper mold 12 were variously changed to the conditions shown in Table 1. It took 7 to 20 seconds to reach the predetermined degree of reduced pressure.

The appearance of the obtained minibus was evaluated by observing the appearance according to the following four-level evaluation criteria. 0: No appearance, 1: Little appearance, 2: Fair appearance, 3 prominent appearance. As another test method, in the state shown in FIG.
The upper mold 12
The bubble generation area of the tip portion 21 of the BMC 2 not in contact with was observed and expressed as a ratio of each example. In the vicinity of the bubbles, there was a part that appeared white due to diffuse reflection of light. The above results are shown in Table 1.
Are also shown.

[0034] It was not a comparative example under reduced pressure, except that the moving speed of the upper die 12 (pressurization rate) was set under conditions shown in Table 1 in the same manner as in Example 1-4, the pressing of the minibus Did and got a minibus. And the result evaluated similarly to Examples 1-4 is also shown in Table 1.

[0035]

[Table 1]

As is clear from Table 1, the flow patterns appear in all of Examples 1 to 4, whereas the flow patterns do not appear in the comparative examples.

[0037]

EFFECTS OF THE INVENTION Since the method for producing a thermosetting resin irregularly shaped product of the present invention is configured as described above, it is a thermosetting resin irregularly shaped product having a high productivity and a beautiful and deep flow pattern. Molded product can be obtained

[0038]

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a mold used in the present invention.

FIG. 2 is a cross-sectional view illustrating a process of an example of the present invention.

FIG. 3 is a cross-sectional view illustrating a process of an example of the present invention.

FIG. 4 is a cross-sectional view illustrating a process of an example of the present invention.

FIG. 5 is a perspective view showing the obtained minibus.

[Explanation of symbols]

 1 type 2 BMC 3 minibus 11 lower type (fixed type) 12 upper type (movable type) 13 cavity 14 O-ring 31 flow pattern 117 decompression path

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Claims (1)

[Claims] 1. A bulk resin comprising an unsaturated polyester resin containing a copolymerizable monomer, a reinforcing material, and an inorganic filler.
A method of manufacturing a thermosetting resin profiled molded product in which a molding compound is supplied into a mold consisting of a fixed mold and a movable mold in a heated state, and the mold is closed to perform pressure molding, wherein the compound is supplied into the fixed mold. After that, when the movable mold is moved to close the mold under reduced pressure, the movable mold is brought into contact with at least a part of the compound to form the surface of the molded product of the compound which is not yet in contact with the movable mold. A method for producing a thermosetting resin irregularly shaped product, characterized in that a mold is completely closed after a vapor bubble of a copolymerizable monomer is generated in a different part.