JP2003192810A - Sheet molding compound and molded product using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet molding compound by using a powdery unsaturated polyester resin instead of conventional calcium carbonate in an unsaturated polyester resin composition and organic fibers instead of conventional glass fibers to bring a molded product of the sheet molding compound to have a lower specific gravity and a lower weight than those of conventional molded products. <P>SOLUTION: This sheet molding compound is prepared by impregnating a base organic fiber material with the unsaturated polyester resin compound comprising the unsaturated polyester resin, a polymerizable monomer, a low shrinkage agent, a curing agent, a thickener and a filler. As the filler, the powdery unsaturated polyester resin is used in 10-60 mass% based on the unsaturated polyester resin composition. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loom tank, a washing room pan, a loom chamber equipment such as a melting chamber wall panel, a panel assembly type water tank,
The present invention relates to a sheet molding compound (hereinafter referred to as SMC) which is a molding material used for a septic tank and the like, and a molded product obtained by molding the SMC.

[0002]

2. Description of the Related Art SMC is an unsaturated polyester prepared by diluting a vinyl-based monomer with additives such as a low-shrinking agent, a curing agent, a polymerization inhibitor, a filler, a thickener, a release agent, and coloring. It is a molding material obtained by impregnating glass fiber into a paste mixed with an agent or the like to form a sheet, covering both sides with a carrier film, aging and semi-solidifying. The SMC is placed on a mold and pressure-heated and molded, and is manufactured as an SMC molded product such as a tank, a panel assembly type water storage tank, and a septic tank.

[0003]

The SMC molded article which has been pressure-heat molded as described above has excellent durability, water resistance, mechanical strength, gloss of the surface of the molded article, and the degree of freedom of shape. It is widely used as a storage tank device such as a storage tank, a panel assembly type water storage tank, and a septic tank because of its large size and excellent design. However, the above-mentioned SMC molded product has a problem in recyclability and industrial waste treatment as compared with dicyclopentadiene, a thermoplastic resin molded product and the like. That is,
The SMC molded product generally contains 10 to 50% by mass of glass fiber as a reinforcing material, and further contains inorganic substances such as calcium carbonate and aluminum hydroxide as a filler. Therefore, when performing heat recovery and recycling with cement combustion raw materials, etc., it sinks into other thermoplastic resin molded products, the heat generation amount is low and the heat recovery efficiency is poor, or glass fibers and inorganic fillers remain and There are problems such as a large amount of waste disposal. In addition, since material recycling contains glass fibers, it is difficult to separate them, and it is impossible at present. Therefore, landfill treatment is unavoidable, which is becoming an environmental problem. In addition, since SMC molded products contain high pillow weight glass fibers and inorganic fillers, they have a higher specific gravity than dicyclopentadiene resins and thermoplastic resins, making it difficult to reduce the weight of products and inferior in workability. . For this reason, SMC molded articles are being replaced by dicyclopentadiene resins and thermoplastic resin containing no glass fibers in septic tanks, panel assembly type water tanks, exterior members for automobiles, etc. .

The present invention has been made in view of the above problems, and an object thereof is to provide an SMC and / or an SMC molded product which is excellent in recyclability and molding appearance.

[0005]

The present invention relates to the following. (1) A filler in a sheet molding compound obtained by impregnating an organic fiber base material with an unsaturated polyester resin composition containing an unsaturated polyester resin, a polymerizable monomer, a low shrinkage material, a curing agent and a thickener. A sheet molding compound, wherein an unsaturated polyester resin powder is used as, and the content of the unsaturated polyester resin composition is 10% by mass or more and 60% by mass or less. (2) Average particle size of unsaturated polyester resin powder is 3μm
The sheet molding compound according to item (1), which has a thickness of 600 μm or less. (3) A sheet molding compound molded product obtained by press-molding the sheet molding compound according to item (1) or (2).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The sheet molding compound (SMC) in the present invention is a fiber reinforced obtained by blending an unsaturated polyester resin, a polymerizable monomer, a low-shrinking agent, a curing agent, a thickener and a fiber reinforcing material. A molding material, which is formed into a sheet shape.

The unsaturated polyester resin in the present invention is obtained by reacting a polybasic acid component containing α, β-unsaturated polybasic acid or its anhydride as an essential component with a polyhydric alcohol. In the present invention, as the α, β-unsaturated polybasic acid or its anhydride, which is a synthetic raw material of the unsaturated polyester resin, for example, α, β-unsaturated dibasic acid or its anhydride, for example, maleic acid, Examples thereof include fumaric acid, itaconic acid, citraconic acid, maleic anhydride, and their anhydrides. You may use 2 or more types together. Examples of the polybasic acid component include α, β-unsaturated polybasic acids or their anhydrides as well as saturated polybasic acids in order to adjust the concentration of unsaturated groups, and impart properties such as flexibility and heat resistance. It is preferable to use a basic acid or its anhydride together. At this time, α, β-
The unsaturated polybasic acid or its anhydride is preferably 40 mol% or more of the polybasic acid component. α, β-
When the unsaturated polybasic acid or its anhydride is less than 40 mol%, the strength of the obtained molded article tends to gradually decrease. From this, it is more preferable that the α, β-unsaturated polybasic acid or its anhydride is 45 to 80 mol%.
It is particularly preferably from 0 to 70 mol%.

Examples of the saturated polybasic acid or its anhydride 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 adduct, etc. To be These may be used in combination of two or more.

As the polyhydric alcohol which is another raw material for synthesizing the unsaturated polyester resin, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,
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 1.
It is more preferable to use in the range of 1.05. When the amount of polyhydric alcohol is small, the molecular weight of the unsaturated polyester resin obtained tends to be small, and when it is large, the acid value is small and the progress of thickening by the thickener tends to be slow.

The unsaturated polyester resin can be produced by a conventionally known method. For example,
Condensation reaction of polybasic acid component and polyhydric alcohol component,
The process proceeds while removing the condensation water generated when both components react with each other. Removal of the condensed water to the outside of the system is preferably carried out by natural distillation or reduced pressure distillation by passing an inert gas. A solvent such as toluene or xylene can be added to the system as an azeotropic component in order to accelerate the distillation of the condensed water. The progress of the reaction can be generally known by measuring the amount of distillate produced by the reaction, quantifying the terminal functional group, measuring the viscosity of the reaction system, and the like. The reaction temperature is preferably 150 ° C. or higher, and the reaction is preferably carried out while aerating an inert gas such as nitrogen or carbon dioxide to prevent side reactions due to oxidation. From this, as the reaction apparatus, those made of glass, stainless steel or the like are selected, and the stirring apparatus, the fractionation apparatus for preventing the distillation of the alcohol component due to the azeotropic distillation of water and the alcohol component, and the temperature of the reaction system are increased. It is preferable to use a reaction device equipped with a heating device, a temperature control device for this heating device, and a device for blowing in an inert gas such as nitrogen.

The number average molecular weight of the unsaturated polyester resin is preferably 2,500 to 4,500. Molecular weight is 2
If it is lower than 500, the viscosity does not increase even if an appropriate amount of a thickener is added, and when it is made into a resin composition, it becomes soft and the workability deteriorates. When the molecular weight is larger than 4,500, the viscosity is high and impregnation of the glass fiber is caused to cause poor surface gloss when molded.

Examples of the polymerizable monomer used in the present invention include styrene, chlorostyrene, divinylbenzene, tert-butylstyrene, styrene derivatives such as styrene bromide, methyl methacrylate, ethyl methacrylate, ethyl acrylate. , Methacrylic acid such as butyl acrylate or alkyl ester of acrylic acid, β-hydroxyethyl methacrylate, methacrylic acid such as ethyl β-hydroxyacrylate or hydroxyalkyl ester of acrylic acid, diallyl phthalate, acrylamide, phenylmaleimide, etc. To be Also, polyfunctional methacrylic acid or acrylic acid esters such as ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, and trimethylol propane trimethacrylate can be used.

The unsaturated polyester resin and the polymerizable monomer are preliminarily blended with each other, and if necessary, a polymerization inhibitor is added to obtain a composition. At this time, the mixing ratio of the unsaturated polyester resin and the polymerizable monomer is 100 in total.
The unsaturated polyester resin is 25 to 8 parts by weight.
It is preferable that the amount of the polymerizable monomer is 0 parts by weight and the polymerizable monomer is 75 to 20 parts by weight. If it is less than 25 parts by weight, the viscosity of the unsaturated polyester resin composition is too low to be applied in a sheet form,
In addition, it becomes difficult to uniformly mix with other components due to sedimentation and the like, and even when the obtained fiber reinforced molding material is molded, the curing shrinkage rate is large, and the molded product may be cracked or cracked. If the unsaturated polyester resin exceeds 80 parts by weight, the viscosity may be too high and it may be difficult to apply or mix with other components. From this, the unsaturated polyester resin is 40 to 65 parts by weight, and the polymerizable monomer is 60 to 3 parts by weight.
More preferably, it is 5 parts by weight. Examples of the polymerization inhibitor include p-benzoquinone, naphthoquinone, toluquinone, 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 has a storage stability of 0.
It is preferable that the content is at least 05% by weight.

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

As the curing agent used in the present invention, ketone peroxides, peroxydicarbonates, hydroperoxides, diacyl peroxides,
Peroxyketals, dialkyl peroxides,
Examples thereof include peroxyesters and alkyl peresters. The amount of the curing agent affects not only the molding cycle but also the storability of the material, color unevenness, and the like, and thus is determined depending on each. From the standpoint of the storability of the material and the molding cycle, it 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.

Magnesium oxide, magnesium hydroxide, potassium oxide, potassium hydroxide and the like are used as the thickener, but magnesium oxide is generally used. The amount of the thickener is determined according to the workability of the molding material, but is preferably 0.5 to 5% by weight, and more preferably the total amount of the unsaturated polyester resin and the polymerizable monomer. It is 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 increase too much to be controlled.

In the present invention, unsaturated polyester resin powder is used as the filler. The unsaturated polyester resin powder referred to here is a cured product of the unsaturated polyester resin as described above, a cured product of the unsaturated polyester resin as described above dissolved in a polymerizable monomer, or an unsaturated polyester resin as described above. Examples include cured products of saturated polyester resin compositions. Further, a cured product of a fiber reinforced unsaturated polyester resin composition or the like can be used, and the fiber includes organic fibers such as glass fiber and polyester fiber, and the unsaturated polyester resin composition is as described above. There is something like this.

Further, unsaturated polyester resin powder is added to the unsaturated polyester diluted with the vinyl monomer so that the content of the unsaturated polyester resin powder in the unsaturated polyester resin composition is 10% by mass or more and 60% by mass or less. To be The content of the unsaturated polyester resin powder in the unsaturated polyester resin composition is defined by the alkaline earth metal oxide such as magnesium oxide of the unsaturated polyester resin composition when the content is less than 10% by mass. This is because the thickening reaction is difficult to proceed, the tack-free property after thickening is insufficient, workability is deteriorated due to stickiness during handling, and defects such as pinholes are likely to occur during press molding. On the other hand, when the unsaturated polyester resin powder exceeds 60% by mass, the viscosity of the unsaturated polyester resin composition is remarkably increased and the impregnation property into the organic fiber base material is deteriorated, resulting in defects such as blisters, cavities and pinholes during molding. Is caused.

Inorganic fillers, mold release agents, stabilizers, colorants and the like are further added to the above unsaturated polyester resin composition.

As the release agent, zinc stearate, calcium stearate, etc. are used. The amount of the releasing agent is preferably 1 to 10% by weight, and more preferably 2 to 10% by weight based on the total amount of the unsaturated polyester resin and the polymerizable monomer.
It is 4% by weight. If the amount of the release agent is too small, the amount of less than 1 part by weight may cause the molded product to stick to the mold, make it difficult to remove the mold, and cause the molded product to be cracked. Further, if the amount of the release agent is too much, the strength of the molded product tends to be lowered.

Organic fibers are used as the fiber reinforcing material. The content of this organic fiber in SMC is 2 to 40% by mass.
Is preferred. This is because if it is less than 2% by mass, the reinforcing effect is not sufficient and the strength of the obtained SMC molded product is insufficient. On the other hand, if it exceeds 40 mass, the impregnating property into the unsaturated polyester resin composition will decrease, defects such as fiber grains, blisters, cracks and pinholes will occur in the molded product, impairing the appearance of the product and lowering the strength. This is because it will end up. The organic fiber used may be a non-woven fabric, cloth, chopped short fibers, or the like, but the non-woven fabric has a resin flowability higher than that of the cloth during SMC molding (manufacturing of a molded product). Good, uniform dispersibility of fibers and resin impregnation are better than chopped short fibers. The length of the organic fibers constituting the organic fiber base material is preferably 3 to 150 mm. If the fiber length is less than 3 mm, the reinforcing effect is insufficient and the strength of the molded product is insufficient, and if it exceeds 150 mm, the flowability of the resin at the time of molding is poor, the appearance of the molded product is impaired, and the filling property into ribs and bosses is also This is because the use and shape of the molded product are limited. As the above-mentioned organic fibers, synthetic fibers such as polyester fibers, cellulose fibers, nylon fibers, and aramid fibers, and natural fibers such as sisal and jute can be used, but the polyester fibers have adhesiveness with the unsaturated polyester resin. It is preferable because it is excellent in Further, natural fibers such as sisal and jute are cheaper than synthetic fibers, and moreover, natural products can be effectively used, and therefore they are suitable from the viewpoint of environmental consideration.

The SMC can be manufactured by an ordinary method using an ordinary SMC producing apparatus. For example, the unsaturated polyester resin composition is applied to a carrier film arranged above and below so as to have a uniform thickness, and a fiber reinforcing material (woven cloth or nonwoven cloth) of a predetermined size unwound from an unwinding device. ) Is inserted into the unsaturated polyester resin composition of the carrier film arranged above and below, and then the whole is passed between impregnating rolls, and pressure is applied to the fiber reinforcement to the unsaturated polyester resin composition. After impregnation, it is wound into a roll and folded into a zigzag. In the case of using single fibers as the fiber reinforcing agent, there is also a method of applying an unsaturated polyester resin composition to a carrier film and then sprinkling the single fibers on it. After that, aging or the like is performed if necessary. When a thickener is added, it is preferable to heat it at a temperature of room temperature to 60 ° C. for aging.
A polyethylene film, a polypropylene film, or the like can be used as the release film.

The viscosity of SMC is 100 at 40 ° C.
It is preferably adjusted to be 0 to 18,000 Pa · s. If the viscosity is too low, scumming tends to occur on the surface of the molded product, and if the viscosity is too high, the mold clamping time tends to be long and the molding cycle tends to be long. The viscosity of the fiber-reinforced molding material is 1,500 Pa · s at 40 ° C.
It is more preferably adjusted to 15,000 Pa · s, and particularly preferably adjusted to 3,500 to 12,000 Pa · s. However, the optimum viscosity of the fiber-reinforced molding material is determined by the molded product. Further, the viscosity of the fiber-reinforced molding material can be adjusted by the blending amount of the thickener and the aging conditions.

SMC is molded by compression molding, transfer molding, etc., and a wide range of FRP molded products can be obtained. Molding temperature is 70-150 ° C, molding pressure is 0.1
It is preferably 10 MPa.

When the SMC produced as described above is used, cracks are less likely to occur when it is subjected to an impact during transportation or the like, and it is excellent for a large-scale container such as a panel assembly type water storage tank, a septic tank, and a large-sized molded product. It can have characteristics.

[0027]

EXAMPLES In the following, Polyset PS-9415 was used as an unsaturated polyester resin diluted with styrene.
(Styrene solution containing 40% by mass of unsaturated polyester resin,
Hitachi Chemical Co., Ltd. product name) and polystyrene (Dencast styrol, Denki Kagaku Kogyo Co., Ltd. product name) were used as the low-shrinking agent.

Examples 1 to 4 and Comparative Examples 1 to 4 (Preparation of SMC) 80 parts by mass of unsaturated polyester resin dissolved in styrene (60 parts by mass of styrene) and 20 parts by mass of polystyrene dissolved in styrene (60 parts of styrene).
% By weight), and 100 parts by weight of a mixture of unsaturated polyester diluted with styrene of the polymerizable monomer and polystyrene dissolved in styrene, based on 100 parts by weight of the curing agent.
Butyl peroxybenzoate 1 part by mass, polymerization inhibitor parabenzoquinone 0.05 part by mass, mold release agent zinc stearate 4 parts by mass, and thickener magnesium oxide 0.8.
An unsaturated polyester resin composition was obtained by blending parts by mass and an unsaturated polyester resin powder as a filler.
The unsaturated polyester resin powder was blended with the unsaturated polyester resin composition in a ratio shown in Table 1. The unsaturated polyester resin composition obtained by blending as described above is added with a predetermined content by a usual method using a woven fabric of predetermined organic fibers or glass fibers as shown in Table 1 or a normal method using single fibers. Was impregnated with SMC to prepare SMC. The polyester fibers used in Examples and Comparative Examples were polyethylene terephthalate fibers, and the fiber diameters were all 25 μm. In addition, the basis weight of each of the nonwoven fabrics of polyester fiber was 200 g / m ² . The glass fiber used in Comparative Example 3 has a fiber diameter of 13 μm. Unsaturated polyester resin powder means an average particle size of 1
It is a cured product of an unsaturated polyester resin composition of about 30 μm. Here, the unsaturated polyester resin composition is Polyset PS-9415 (trade name of Hitachi Chemical Co., Ltd.).
The hardened | cured material of was used.

Manufacture of Molded Article Using the SMC obtained above, a 220 cm square flat plate was pressure-heated and molded. The molding conditions are as follows: SMC input weight 1.5 kg, charge area 0.05 m ² (15 cm
Corner), the molding pressure was 9 MPa, and the holding time was 4 minutes.

Test Method (1) Impregnating Property of Fiber Base Material The fiber base material in the obtained SMC sheet was observed with a cutter knife while removing the resin on the surface, and the fiber base material where the resin was not impregnated was observed. The presence or absence was visually judged. The case where there was no part of the fiber base material not impregnated with resin was evaluated as ◯, and the case where there was such a part was evaluated as x. (2) Workability The surface of the obtained SMC sheet was observed with a tentacle to check whether the surface was sticky. The case where stickiness was not felt was evaluated as ◯, and the case where stickiness was felt was evaluated as x. (3) Specific gravity of molded product Measured with an electronic balance-type specific gravity meter. (4) Calorific value at the time of burning and residual SMC molded product at 600 ° C with a differential thermogravimetric simultaneous measurement device
The amount of heat generated when treated for 2 hours and the amount of residue after treatment were measured. In the SMC molded product of Comparative Example 1, the balance is 70% by mass.
Then, while the glass fibers were contained therein, the SMC molded articles of Examples 1 to 4 had a residual content of 50% by mass, and were completely fine powder because the glass fibers were not present. Also, the calorific value was high because there were many combustible parts per unit weight.

[0031]

[Table 1]

[0032]

EFFECTS OF THE INVENTION SMC using unsaturated polyester resin powder in place of conventional calcium carbonate in an unsaturated polyester resin composition, and organic fiber in place of conventional glass fiber as a reinforcing material, and a molded article thereof. Is the conventional SM
It has a lower specific gravity than C-molded products and is useful for reducing the weight of products.

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Claims (3)

[Claims] 1. A sheet obtained by impregnating an organic fiber base material with an unsaturated polyester resin composition containing an unsaturated polyester resin, a polymerizable monomer, a low shrinkage material, a curing agent, a thickener and a filler. A sheet molding compound, wherein an unsaturated polyester resin powder is used as a filler in a molding compound, and the content of the unsaturated polyester resin composition is 10% by mass or more and 60% by mass or less. 2. The sheet molding compound according to claim 1, wherein the average particle size of the unsaturated polyester resin powder is 3 μm or more and 600 μm or less. 3. A sheet molding compound molded product obtained by press-molding the sheet molding compound according to claim 1 or 2.