JP2003049001A - Sheet molding compound and molded product using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheet molding compound(SMC) and to provide a molded product of the SMC both having excellent recyclability, and a lightweight SMC and a molded product of the SMC by using a low-specific gravity fiber. SOLUTION: The SMC is obtained by impregnating a synthetic fiber substrate and a natural fiber substrate with an unsaturated polyester composition comprising an unsaturated polyester resin, a polymerizable monomer, a weak shrinking material, a curing agent and a thickener. The SMC is characterized in that the content of the synthetic fiber substrate and natural fiber substrate is 1-40 mass%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to bath equipment such as bathtubs, washing pans, and bathroom wall panels, panel assembly type water storage tanks,
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 diluted with a vinyl monomer, and has 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 a paste mixed with an agent and the like with glass fibers to form a sheet, covering both sides with a carrier film, and aging to semi-solidify. This SMC is placed on a mold and pressure-heat molded, and is manufactured as an SMC molded product such as a bath, 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 bathroom equipment such as bathtubs, panel assembly type water storage tanks, septic tanks, etc. 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,
Generally, SMC molded products contain 10 to 50% by mass of glass fiber as a reinforcing material. Therefore, when heat recovery and recycling is performed with a cement combustion raw material, etc., compared to other thermoplastic resin molded products. However, there is a problem that the amount of generated heat is low and the heat recovery efficiency is low, or the amount of waste disposal after combustion is large because glass fibers remain.

Further, since the material recycling contains glass fibers, it is difficult to separate them, and it is impossible at present, and it is inevitable to reclaim the land, which is becoming an environmental problem. Further, since the SMC molded product contains glass fiber having a high specific gravity, it has a higher specific gravity than dicyclopentadiene resin or a thermoplastic resin, making it difficult to reduce the weight of the product and inferior in workability. Because of this, SMC
Molded articles are septic tanks, panel assembly type water storage tanks, exterior members for automobiles, etc., and their applications are being replaced by dicyclopentadiene resins and thermoplastic resins that do not contain glass fibers.

The present invention has been made in view of the above problems, and an object thereof is to provide an SMC and an SMC molded product which are excellent in recyclability. Another object is to provide a lightweight SMC and SMC molded product by using a fiber having a low specific gravity.

[0006]

The present invention relates to the following. 1. Synthetic fiber in a sheet molding compound obtained by impregnating a synthetic fiber base material and a natural fiber base material with an unsaturated polyester composition containing an unsaturated polyester resin, a polymerizable monomer, a low shrinkage material, a curing agent and a thickener. A sheet molding compound, wherein the contents of the base material and the natural fiber base material are 1 to 40% by mass. 2. Synthetic fiber in a sheet molding compound obtained by impregnating a mixed base material of synthetic fiber and natural fiber with an unsaturated polyester composition containing an unsaturated polyester resin, a polymerizable monomer, a low shrinkage material, a curing agent and a thickener. A sheet molding compound, characterized in that the content of the blended base material of the and natural fibers is 1 to 40% by mass. 3. Item 3. The sheet molding compound according to Item 1 or 2, which is a woven fabric mainly composed of a blended base material of a synthetic fiber base material and a natural fiber base material. 4. Item 4. The sheet molding compound according to Item 1, 2 or 3, wherein the organic fiber base material is a polyester fiber and the natural fiber is mainly sisal. 5. Item 5. A sheet molding compound using a synthetic fiber base material and / or a natural fiber base material, wherein the synthetic fiber base material and / or the natural fiber base material has a water content of 5% or less. 6. Item 5. A synthetic fiber base material or a natural fiber base material having a fiber diameter of 5 mm or less and a sheet molding compound or a synthetic fiber base material and a natural fiber base material having a fiber diameter of 5 mm or less. A sheet molding compound using a mixed fiber of a synthetic fiber base material and a natural fiber base material in which the fiber diameter of the mixed fiber of the fiber base material is 5 mm or less. 7. Item 7. A sheet molding compound molded product obtained by press-molding the sheet molding compound according to any one of items 1 to 6.

[0007]

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, the α, β-unsaturated polybasic acid or its anhydride, which is a raw material for synthesizing the unsaturated polyester resin, is, for example, α, β-unsaturated dibasic acid or its anhydride, for example, 'maleic acid. , Fumaric acid, itaconic acid,
Examples thereof include 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, hiromellitic 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. For this reason, glass, stainless steel or the like is selected as the reaction device, and a stirring device, a fractional distillation device for preventing distillation of the alcohol component due to azeotropy of water and the alcohol component, and the temperature of the reaction system are selected. It is preferable to use a reactor equipped with a heating device for raising the temperature, a temperature control device for this heating device, a device for blowing in 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 is 250
When it is lower than 0, the viscosity does not increase even if an appropriate amount of the thickener is added, and when it is made into a resin composition, it is soft and the workability is deteriorated. 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.

An unsaturated polyester resin composition is prepared by blending an unsaturated polyester resin and a polymerizable monomer, and optionally adding a polymerization inhibitor and the like. The mixing ratio of the unsaturated polyester resin and the polymerizable monomer at this time is 25 to 80 parts by weight of the unsaturated polyester resin and 75 to 100 parts by weight of the polymerizable monomer when the total amount of the two is 100 parts by weight. It is preferably 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 applied in a sheet form, 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 rate is large and the molded product may be cracked or cracked. 80 unsaturated polyester resin
If the amount is more than parts by weight, the viscosity may be too high and it may be difficult to apply or mix with other components. From this, 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, 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 the curing agent is blended, it is preferably contained in an amount of 0.05% by weight or more for storage stability.

As the low-shrinkage agent used in the present invention, a thermoplastic resin such as polymethylmethacrylate, polystyrene, polycaprolactone, polyvinyl acetate, polyethylene or butadiene rubber is 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, peroxycarbonates, hydroperoxides, diacyl peroxides,
Peroxyketals, dialkyl peroxides,
Peroxydiesters, alkyl peresters and the like can be mentioned. 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.

As the thickener, magnesium oxide, magnesium hydroxide, potassium oxide, potassium hydroxide or the like is used, 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.

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

Examples of the inorganic filler include silica sand, calcium carbonate, talc, clay and the like. The compounding amount of the inorganic filler is 100 to 200 with respect to 100 parts by mass of the mixture of the unsaturated polyester resin, the polymerizable monomer and the low-shrinking agent.
It is preferably part by mass.

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.

As the fiber reinforcing material, synthetic fibers and natural fibers are used. The content of these synthetic fibers and natural fibers in SMC is preferably 1 to 40% by mass. This is because if it is less than 1% 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 synthetic fiber and natural fiber used may be woven cloth, cloth, chopped short fiber, or the like, but the woven cloth is more preferable than cloth at the time of molding SMC (manufacturing a molded article). The resin has good fluidity, and the uniform dispersibility of the fibers and the resin impregnation are better than chopped short fibers. The length of the synthetic fiber and the natural fiber constituting the synthetic fiber and the natural 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 fluidity of the resin at the time of molding is poor, the appearance of the molded product is impaired, and the fillability of ribs and posts is also improved. This is because the use and shape of the molded product are limited. Further, the fiber diameter of the synthetic fiber and the natural fiber constituting the synthetic fiber and the natural fiber base material is preferably 5 mm or less. This is because if it exceeds 5 mm, the impregnation property of the resin is poor, the strength of the molded product becomes insufficient, the appearance is impaired, and the use and shape of the molded product are limited. In particular, inexpensive natural fibers do not have a constant fiber diameter, and the base material diameter may exceed 5 mm even when twisted under the same conditions. Therefore, by mixing or blending synthetic fibers with a constant fiber diameter, The upper limit of the quality control of 5 mm was not exceeded. The fiber diameter is preferably 10 μm or more. As the synthetic fiber, polyester fiber, cellulose fiber, nylon fiber, aramid fiber or the like can be used, but polyester fiber is preferable because it has excellent adhesion to the unsaturated polyester resin. As natural fibers, soft fibers such as flax, ramie, hemp, jute,
In addition to fibers such as commercial hemp, kenaf, roselle, malpa, and sun hemp, it is possible to use hard fibers such as Manila hemp, sisal hemp, and Coyer fiber, but since sisal fiber is excellent as a fiber reinforcing material, It is suitable. The water content of the synthetic fiber base material and the natural fiber base material used here is preferably 5% or less. Thickeners such as magnesium oxide are added due to the workability of the molding material, but when the moisture content of the fiber base material is high, the thickener and moisture react, so the thickening effect is lost and SMC The viscosity remains low,
Workability will not be improved. At this time, the upper limit of the moisture content of the fiber base material is about 5%. In particular, since the moisture content of natural fiber varies depending on the season and the place of origin, it is difficult to control the moisture content of the base material. The control of the moisture content was facilitated (the upper limit of the moisture content in the mixed spinning was set to 5%).

There are five ways of using synthetic fibers and natural fibers as a base material for blended spinning, that is, a method for producing SMC. First, the first is a method of twisting synthetic fibers and natural fibers, cutting the twisted fibers to a fiber length of 3 to 150 mm, chopping them, and spraying them on unsaturated polyester resin. The second is Weaving a twisted yarn of synthetic fiber and natural fiber, that is, forming a woven cloth, and sandwiching it between the unsaturated polyester resin and the carrier film. There is a method of spraying on saturated polyester resin. The fourth is a method in which a woven fabric of synthetic fibers and natural fibers is sandwiched between an unsaturated polyester resin and a carrier film, and the twisted yarn of synthetic fibers and natural fibers is cut, and then chopped and scattered. For the eyes, there is a method in which a synthetic fiber and a natural fiber woven cloth is sandwiched between an unsaturated polyester resin and a carrier film, and the synthetic fiber and the natural fiber are cut, respectively, and chopped and scattered.

The SMC can be manufactured using a normal SMC manufacturing apparatus. The unsaturated polyester resin composition is applied to the carrier films arranged above and below so as to have a uniform thickness, and the fiber reinforcing material of a predetermined size unwound from the unwinding device is arranged above and below. The carrier film is sandwiched between unsaturated polyester resin compositions, and then the whole is passed between impregnating rolls, pressure is applied to impregnate the unsaturated polyester resin composition with the fiber reinforcement, and then wound into a roll shape. Fold it in a fold. 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.

The SMC molding method includes a method of charging the SMC in a molding machine and a method of simultaneously charging the woven cloth of synthetic fibers and natural fibers and SMC in the molding machine. SMC is molded by compression molding, transfer molding, etc., and a wide range of FRP molded products can be obtained.
Molding temperature is 60-150 ° C, molding pressure is 0.1-10M
Pa is preferable.

When the SMC produced as described above is used, the weight can be reduced and the transportation is easy, and cracks are less likely to occur when an impact is applied, so that other large containers such as a panel assembly type water storage tank and a septic tank can be obtained. It is possible to give excellent properties to housing equipment, molded parts of automobile members, and the like.

[0028]

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., trade name) and polystyrene (Dencast styrol, Denki Kagaku Kogyo Co., Ltd. trade name) were used as the low-shrinking agent.

Examples 1 to 5 and Comparative Examples 1 to 6 (Preparation of SMC) 80 parts by mass of unsaturated polyester resin dissolved in styrene (60% by mass of styrene) and 20 parts by mass of polystyrene dissolved in styrene (60 parts by mass of styrene) %), And 1 part by mass of t-butylperoxybenzoate as a curing agent, 100 parts by mass of a mixture of an unsaturated polyester diluted with styrene as a polymerizable monomer and polystyrene dissolved in styrene, and a polymerization inhibition. 0.05 parts by mass of parabenzoquinone as an agent, 4 parts by mass of zinc stearate as a release agent, and 0.8 parts by mass of magnesium oxide as a thickener were added. The unsaturated polyester resin composition obtained by blending in this way is impregnated with predetermined synthetic fibers and natural fibers at a predetermined content as shown in Table 1 or Table 2, and S
MC was produced.

Manufacture of Molded Product 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 while removing the resin on the surface with a cutter knife, and the fiber base material not impregnated with the resin was examined. The presence or absence was visually judged. The case where there was no part of the fiber base material not impregnated with the resin was evaluated as ◯, and the case where there was such a part was evaluated as x. (2) Appearance of molded product The obtained molded product was visually observed to check the degree of SMC filling, and the presence or absence of defects such as blisters, cavities, and pinholes. Those without defects were evaluated as ◯, and those with defects were evaluated as x. (3) Specific gravity of molded product Measured with an electronic balance-type specific gravity meter. (4) Bending strength According to JIS K6911, it was measured by a tensile tester manufactured by Orientec Co., Ltd. (5) Calorific value at the time of burning and residual SMC molded product at 600 ° C with a differential thermogravimetric simultaneous measurement device
The heat generation amount and the residual amount after the treatment were measured after 2 hours. In the SMC molded product of Comparative Example 1, the balance is 70% by mass.
While the glass fibers were contained therein, the SMC molded articles of Examples 1 to 5 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.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

The SMC obtained by impregnating the unsaturated polyester resin composition with the synthetic fiber and the natural fiber base material in place of the conventional glass fiber and the molded article thereof do not contain the glass fiber which cannot be incinerated, and therefore the incineration residue. Since it has a small amount, the thermal efficiency is high even as a cement combustion raw material, and the residue is also in powder form, so that disposal is easy. Further, since synthetic fibers and natural fibers having a low specific gravity are used instead of glass fibers, the specific gravity of the molded product can be reduced, which is useful for reducing the weight of the product. Since plant-based natural fibers are used, the production energy thereof is low, and it is possible to reduce the amount of petrochemical resources used and the load on the global environment.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Hasegawa             Hitachi, Shimodate-shi, Ibaraki Prefecture 1250 Shimoeren             Seikou Co., Ltd.Yuki Works F-term (reference) 4F072 AA02 AA04 AA07 AA09 AB03                       AB05 AB06 AB22 AB28 AD05                       AD38 AE02 AF04 AF06 AF17                       AG03 AG18 AH04 AH11 AH12                       AH13 AJ03 AK05 AK14 AK20                       AL02 AL06 AL07                 4F204 AA41 AD16 AH17 AH49 FA01                       FB01 FG02 FG09 FN11 FN15

Claims (7)

[Claims] 1. A sheet obtained by impregnating a synthetic fiber base material and a natural fiber base material with an unsaturated polyester composition containing an unsaturated polyester resin, a polymerizable monomer, a low shrinkage material, a curing agent and a thickener. A sheet molding compound, wherein the content of the synthetic fiber base material and the natural fiber base material in the molding compound is 1 to 40% by mass. 2. A sheet obtained by impregnating a mixed base material of synthetic fibers and natural fibers with an unsaturated polyester composition containing an unsaturated polyester resin, a polymerizable monomer, a low shrinkage material, a curing agent and a thickening agent. A sheet molding compound, wherein the content of the blended base material of synthetic fibers and natural fibers in the molding compound is 1 to 40% by mass. 3. The sheet molding compound according to claim 1, which is a woven fabric mainly composed of a blended base material of a synthetic fiber base material and a natural fiber base material. 4. The sheet molding compound according to claim 1, 2 or 3, wherein the organic fiber base material is mainly composed of polyester fiber and natural fiber. 5. A sheet using the synthetic fiber base material and / or natural fiber base material according to claim 1, wherein the moisture content of the synthetic fiber base material and / or natural fiber base material is 5% or less. Molding compound. 6. A sheet molding compound using the synthetic fiber base material and natural fiber base material according to claim 1, wherein the synthetic fiber base material and the natural fiber base material have a fiber diameter of 5 mm or less. A sheet molding compound using a mixed fiber of a synthetic fiber base material and a natural fiber base material having a fiber diameter of 5 mm or less. 7. A sheet molding compound molded product obtained by press-molding the sheet molding compound according to claim 1.