JP2001150434A - Method of manufacturing sheet molding compound, sheet molding compound obtained by this method and molded article using sheet molding compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a thick-walled sheet molding compound(SMC) enhanced in the infiltration properties of a resin compound to a fiber reinforcing material. SOLUTION: In a method of manufacturing SMC by applying a resin compound to a thermoplastic film by an applicator such as a doctor blade or the like while cutting reinforcing fibers by a chopper and applying the cut reinforcing fibers to the resin compound applied to the thermoplastic film to impregnate them with the resin compound by an impregnation device, a plurality of polymerizable vinyl monomer applicators and a plurality of reinforcing fiber choppers are provided as essential devices.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a sheet molding compound (hereinafter abbreviated as SMC),
The present invention relates to an SMC obtained by this method and an SMC molded product using this SMC.

[0002]

2. Description of the Related Art SMC is made by impregnating a reinforcing compound such as glass fiber with a resin compound obtained by adding a filler, a curing agent and a thickener to a thermosetting resin such as an unsaturated polyester resin, and forming the sheet into a sheet. The obtained thermosetting resin molding material is mainly molded under pressure and widely used for large molded products such as housing equipment, transportation equipment, industrial parts and the like.

FIG. 1 shows a schematic view of a conventional apparatus for manufacturing an SMC. First, the resin compound 1 is applied to the separate film 3 by an application device 2 such as a doctor blade. These are prepared one by one at the top and bottom.

On the other hand, the glass rovings 4 are cut by a chopper 5, sandwiched by a resin compound 1 applied to a separate film 3, and then the glass rovings 7 cut by an impregnation device 6 are impregnated with the resin compound 1. Let me do. Thus, the SMC is manufactured. .

[0005] However, in such a conventional SMC manufacturing apparatus, the cut glass roving is only sandwiched between resin compounds on a separate film, so that the thickness is 5 mm or more. Therefore, even if the application amount of the resin compound is increased in order to produce a so-called thick SMC, it is not possible to sufficiently impregnate the glass layer with the resin compound up to the central portion, and eventually the , Resulting in SMC with poor impregnation.

If such an SMC is formed, it is natural that so-called poor appearance such as blistering and burning of the glass, a decrease in strength, and the like occur. Further, when producing SMC having a high glass content, the production speed must be reduced from the usual 10 to 20 m / min to about 5 to 8 m / min. However, there is a problem that productivity is reduced.

In order to solve this problem, for example,
JP-A-5-220742 discloses that, by using a specific manufacturing device equipped with a plurality of resin compound coating devices and a plurality of glass choppers, two or more glass fiber layers, and thus, The resin compound can be applied between the fiber reinforcement layers, and as a result, furthermore, it is possible to prepare a thick SMC without an unimpregnated part, High content, high fiber reinforcement content, and
An apparatus for producing a resin composition that enables high-strength SMC to be prepared with good productivity is described.

However, according to the method described in the above publication, although it is effective as a manufacturing method for preparing a thick SMC without an unimpregnated portion, it is difficult to use a resin compound coating apparatus when a product type is changed. Since the amount of resin compound applied varies due to an increase in the number of cleaning operations of the coating device and the difficulty in controlling the amount of resin compound applied in accordance with the SMC production speed, the unit weight of the SMC varies.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and improves the impregnation property of the resin compound into the glass fiber, and thus the fiber reinforcement, that is, the impregnation efficiency. It can be further improved, and as a result, furthermore, it becomes possible to prepare a thick-walled SMC without an unimpregnated part, and in addition, a high glass content, a high fiber reinforcement content, and a high strength SMC can be prepared with good productivity, it does not require an increase in the cleaning work of the coating equipment at the time of product type change, and the SMC manufacturing method which does not affect the thickness variation, the SMC manufactured by this method And an SMC molded product using the same.

[0010]

The present invention relates to the following. (1) In a method of manufacturing an SMC in which a reinforcing fiber cut by a pair of resin compounds applied to a thermoplastic film is sandwiched and the reinforcing fiber is impregnated with the resin compound, the reinforcing fiber cut on one resin compound is removed. A sheet characterized by being placed, spraying a polymerizable monomer from above, further placing a cut reinforcing fiber from above, and then sandwiching the other resin compound reinforcing fiber. Manufacturing method of molding compound. (2) An SMC manufactured by the method according to (1). (3) An SMC molded product obtained by subjecting the SMC according to item (2) to pressure and heat molding.

[0011]

FIG. 2 is a schematic view showing an example of an apparatus used for manufacturing an SMC according to the present invention. First, on the lower side, after a resin compound 1 is applied to a separate film 3 by an application device 2 such as a doctor blade, a glass roving 4 is cut by a glass chopper device 5, and the cut glass Roving 7
Is sprinkled thereon to form a layer of glass rovings 7. On this, that is, between the glass fiber layers, the polymerizable monomer is sprayed from the coating device 8. The polymerizable monomer coating device 8 can be used continuously without the need for cleaning at the time of changing the product type at the time of manufacturing the SMC.

Next, another glass roving 4 is further cut by another glass chopper device 5, and the cut glass roving 7 is sprayed thereon. Apart from the above, on the upper side another resin compound 1
It is applied to another separate film 3 by an application device 2 such as another doctor blade, and this is laminated on the above-mentioned layer of the glass roving 7 with the resin compound down. Thereafter, the fibers are sufficiently impregnated into the resin by the impregnation device 6 to obtain SMC.

As the components contained in the SMC in the present invention, an unsaturated polyester resin, a polymerizable monomer, a low-shrinking agent, a curing agent, a thickener, a filler and a reinforcing fiber are essential.

The unsaturated polyester resin of the present invention is obtained by reacting a polybasic acid component containing an α, β-unsaturated polybasic acid or its anhydride as an essential component with a polyhydric alcohol. In the present invention, examples of the α, β-unsaturated polybasic acid or an anhydride thereof, which is a raw material for synthesizing an unsaturated polyester resin, include, for example, α, β-unsaturated dibasic acid or an anhydride thereof, for example, maleic acid, Examples include fumaric acid, itaconic acid, citraconic acid, maleic anhydride, and anhydrides thereof. These may be used in combination of two or more. Examples of the polybasic acid component include α, β-unsaturated polybasic acid or its anhydride, and saturated polybasic acid in order to control the concentration of unsaturated groups and to impart properties such as flexibility and heat resistance. It is preferable to use a basic acid or its anhydride in combination. At this time, α, β-
The unsaturated polybasic acid or its anhydride is preferably at least 40 mol% of the polybasic acid component. α, β-
When the amount of the unsaturated polybasic acid or its anhydride is less than 40 mol%, the strength of the obtained molded article tends to gradually decrease. For this reason, the content of the α, β-unsaturated polybasic acid or its anhydride is more preferably 45 to 80 mol%, and more preferably 5 to 80 mol%.
It is particularly preferred that it is 0 to 70 mol%.

The saturated polybasic acids or anhydrides to be used in combination include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, Hexahydrophthalic acid, hexahydrophthalic anhydride, glutaric acid, adipic acid, sebacic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, dimer acid, succinic acid, azelaic acid, rosin-maleic acid adducts, etc. Can be These may be used in combination of two or more.

Polyhydric alcohols which are another raw material for the synthesis of unsaturated polyester resins include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol,
6-hexanediol, neopentyl glycol, 1,
Examples thereof include dihydric alcohols such as 4-cyclohexanediol and hydrogenated bisphenol A, trihydric alcohols such as glycerin and trimethylolpropane, and tetrahydric alcohols such as pentaerythritol. These may be used in combination of two or more.

The polybasic acid component and the polyhydric alcohol are preferably used in an equivalent ratio of 1 to 1.3 when the polybasic acid component is set to 1;
More preferably, it is used in the range of 1.05 to 1.05. When the polyhydric alcohol decreases, the molecular weight of the resulting unsaturated polyester resin tends to decrease, and when the polyhydric alcohol increases, the acid value decreases and the progress of thickening by the thickener tends to be slow.

As a method for producing the unsaturated polyester resin, a conventionally known method can be used. For example,
Polycondensation reaction with polybasic acid component and polyhydric alcohol component,
The reaction proceeds while removing condensed water generated when both components react. The removal of the condensed water out of the system is preferably carried out by natural distillation or vacuum distillation by passing an inert gas. In order to promote the distillation of condensed water, a solvent such as toluene or xylene can be added to the system as an azeotropic component. The progress of the reaction can be generally known by measuring the amount of distillate generated by the reaction, quantifying the functional group at the end, measuring the viscosity of the reaction system, and the like. The reaction temperature is preferably 150 ° C. or higher, and the reaction is preferably performed while passing an inert gas such as nitrogen or carbon dioxide in order to prevent a side reaction due to oxidation. For this reason, as the reaction apparatus, those made of glass, stainless steel, etc. are selected, and a stirrer, a fractionating apparatus for preventing distillation of the alcohol component by azeotropic distillation of water and the alcohol component, and increasing the temperature of the reaction system It is preferable to use a heating device, a temperature control device for the heating device, and a reaction device provided with a device for blowing an inert gas such as nitrogen.

The number average molecular weight of the unsaturated polyester is 25.
It is preferably from 00 to 4500. Molecular weight 250
If it is lower than 0, even if an appropriate amount of a thickener is added, the thickening does not increase, and when a resin composition is used, problems such as softness and deterioration in workability occur. When the molecular weight is more than 4500, the viscosity is high and impregnation of the glass fiber is impaired.

The polymerizable monomer used in the present invention includes, for example, styrene derivatives such as styrene, chlorostyrene, divinylbenzene, tertiary butyl styrene and styrene bromide, methyl methacrylate, ethyl methacrylate, ethyl acrylate Methacrylic acid or acrylic acid alkyl ester such as butyl acrylate, etc., β-hydroxyethyl methacrylate, β-hydroxyethyl acrylate etc. methacrylic acid or acrylic acid hydroxyalkyl ester, diallyl phthalate, acrylamide, phenylmaleimide and the like. Can be In addition, polyfunctional methacrylic acid or acrylic acid esters such as ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, and trimethylpropane trimethacrylate can also be used.

The unsaturated polyester resin is mixed with a polymerizable monomer, and if necessary, a polymerization inhibitor and the like are added to obtain an unsaturated polyester resin composition. At this time, the mixing ratio of the unsaturated polyester resin and the polymerizable monomer is 25 to 80 parts by weight of the unsaturated polyester resin and 75 to 75 parts by weight of the polymerizable monomer when the total amount of both is 100 parts by weight. Preferably it is 20 parts by weight. When the amount is less than 25 parts by weight, the viscosity of the unsaturated polyester resin composition is too low to be easily applied to a sheet, and it is difficult to uniformly mix with other components due to sedimentation and the like. Even when the material is molded, the curing shrinkage is large, and the molded product may be cracked or cracked. 80 unsaturated polyester resin
If the amount is more than 10 parts by weight, the viscosity may be too high to be applied or to be difficult to mix with other components. For this reason, it is more preferable that the unsaturated polyester resin is 40 to 65 parts by weight and the polymerizable monomer is 60 to 35 parts by weight. Examples of the polymerization inhibitor include p-benzoquinone, naphthoquinone, tolquinone, hydroquinone, mono-t-butylhydroquinone, dibutylhydroxytoluene, and the like. The polymerization inhibitor is preferably used in an amount of 0.5% by weight or less based on the total amount of the unsaturated polyester resin and the polymerizable monomer. When a curing agent is blended, it is preferable to contain 0.05% by weight or more for storage stability.

As the low shrinkage agent used in the present invention, thermoplastic resins such as polymethyl methacrylate, polystyrene, polycaprolactone, polyvinyl acetate, polyethylene and butadiene rubber are used. The amount used is determined in consideration of the shrinkage, surface smoothness, and surface gloss of the molded product, and is not particularly limited. The low-shrinkage agent is preferably used in an amount of 20 to 50% by weight based on the total amount of the unsaturated polyester resin and the polymerizable monomer.

The curing agent used in the present invention includes ketone peroxides, peroxydicarbonates, hydroperoxides, diacyl peroxides,
Peroxy ketals, dialkyl peroxides,
Peroxyesters, alkyl peresters and the like can be mentioned. Since the amount of the curing agent affects not only the molding cycle but also the preservability of the material, color unevenness, and the like, it is determined according to each. From the viewpoints of the storage stability of the material and the molding cycle, the amount is preferably 0.5 to 5% by weight, more preferably 1 to 3% by weight, based on the total amount of the unsaturated polyester resin and the polymerizable monomer.

As the thickener, magnesium oxide, magnesium hydroxide, potassium oxide, potassium hydroxide and the like are used, but generally, magnesium oxide is used. The amount of the thickener is determined depending on the workability of the molding material, but is preferably 0.5 to 5% by weight, more preferably 0.5% by weight, based on the total amount of the unsaturated polyester resin and the polymerizable monomer. 0.7 to 2% by weight. If the amount of the thickener is too small, the viscosity of the resin composition may not increase. On the other hand, if the amount of the thickener is too large, the viscosity may be too high to control.

As the filler, silica sand, calcium carbonate,
Talc, clay and the like. The compounding amount of the filler is preferably 100 to 200 parts by mass based on 100 parts by mass of the mixture of the unsaturated polyester resin, the polymerizable monomer and the low-shrinkage agent.

The above-mentioned unsaturated polyester resin composition is further blended with a releasing agent, a stabilizer, a coloring agent and the like as appropriate.

As the release agent, zinc stearate, calcium stearate and the like are used. The amount of the release agent is preferably 1 to 10% by weight, more preferably 2 to 10% by weight based on the total amount of the unsaturated polyester resin and the polymerizable monomer.
4% by weight. If the amount of the release agent is too small, if the amount is less than 1 part by weight, the molded article may stick to the mold, making it difficult to remove the mold, and cracking the molded article. If the amount of the release agent is too large, the strength of the molded article tends to decrease.

The SMC is formed by compression molding, transfer molding, or the like, so that a wide range of FRP molded products can be obtained. Molding temperature is 70-150 ° C, molding pressure is 0.1
It is preferably from 10 to 10 MPa.

[0029]

EXAMPLES Example 1 With the composition shown in Table 1, each of the components was kneaded,
A resin compound was obtained. Glass roving was used as a reinforcing fiber. 2 of cut glass rovings
The sprays divided into times were made to have the same weight. The obtained resin compound was used to prepare a thick-walled SMC for a residential tub as shown in FIG. 2 using an apparatus for producing an SMC composition according to the present invention.

[Table 1] In 100 parts by weight of the unsaturated polyester resin in Table 1,
It contains 60% by weight of styrene, which is a polymerizable monomer. Some of these were sprayed from the polymerizable monomer coating device 8. Otherwise, all of the above components were mixed to form a resin compound.

The obtained SMC was a thick SMC having a thickness of 8 mm and a unit weight of 8 kg / m ² , and could be produced without an unimpregnated portion. Table 2 shows the results of bathtub appearance comparison and strength property comparison tests obtained by separately molding this SMC and the SMC prepared by the conventional SMC manufacturing equipment.

[Table 2]

As is evident from Table 2, the SMC obtained by the present invention has a molded article appearance and strength physical properties which are somewhat different from those of SMC prepared by a conventional manufacturing apparatus. There was no inferiority. Moreover, since the thick SMC obtained according to the present invention has a large unit weight, the number of SMC charges can be reduced to half when annually measuring large molded products such as units and baths. Therefore, workability can be greatly improved.

Example 2 The procedure was the same as in Example 1. However, the content of glass in the SMC was set to 40% by weight. 12 SMC
It was prepared at a production rate of m / min. Table 3 shows the results of a strength physical property comparison test of the obtained SMC molded product and the SMC molded product obtained by the conventional manufacturing apparatus.

[Table 3]

As is clear from Table 3, the SMC of the present invention
Strength properties of S
There was no inferiority to the strength physical properties of MC.

Further, according to the present invention, the production rate of high strength SMC having a glass content of 40% can be increased from 8 m / min to 12 m / min, and
The productivity could be improved by 50%.

[0035]

According to the present invention, a polymerizable monomer having a double bond capable of polymerizing with an unsaturated polyester or the like, which is used in a resin compound, is provided between a plurality of glass fiber layers.
In addition, by applying it to the fiber reinforced layers, as a result, various fiber reinforced material layers such as a glass fiber layer can be alternately formed into a sheet in a sandwich form, and thus various types of glass fiber and the like can be formed. The impregnating property (impregnation efficiency) into the fiber reinforcement becomes very good.

[0036] Therefore, not only is it possible to manufacture a thick SMC without an unimpregnated portion and without affecting thickness variations, but also there is an advantage that the productivity of a high-strength SMC can be improved. Further, there is also obtained an effect that a cleaning operation of a plurality of coating apparatuses is not required at the time of manufacturing.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a conventional SMC manufacturing apparatus.

FIG. 2 is a schematic view showing an SMC manufacturing apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Resin compound 2 ... Resin compound coating device 3 ... Separate film 4 ... Glass roving 5 ... Chopper 6 ... Impregnation device 7 ... Cut glass roving 8 ... Polymerization monomer coating device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F072 AA02 AB09 AD38 AE01 AF14 AF23 AF26 AG03 AH12 AH13 AH14 AH21 AH41 AJ04 AK05 AK14 AL06 4F201 AB25 AD16 BA03 BC01 BC02 BC12 BC17 BC37 BD02 BD03 BM16 4F205 AB25 AD16 HA06 HA25 HG01 HK29 HM05 HM13

Claims (3)

[Claims] In a method of manufacturing an SMC, in which a reinforcing fiber cut by a pair of resin compounds applied to a thermoplastic film is sandwiched and the reinforcing fiber is impregnated with the resin compound, the reinforcing fiber cut on one resin compound is used. The fiber is placed, the polymerizable monomer is sprayed on the fiber, the reinforcing fiber cut from the fiber is placed on the fiber, and then the other resin compound reinforcing fiber is sandwiched. Manufacturing method of sheet molding compound. 2. A sheet molding compound produced by the method according to claim 1. 3. A sheet molding compound molded product obtained by pressurizing and heating the sheet molding compound according to claim 2.