JP2001123002A - Unsaturated polyester resin composition, unsaturated polyester resin material for molding, fiber-reinforced plastic molded article and method for preparing same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an unsaturated polyester resin composition, an unsaturated polyester resin material for molding, and a fiber-reinforced plastic molded article using the material which can realize a surface flatness sufficient for automotive exterior plates without adding a low-shrinkage agent as well as a method for preparing the article. SOLUTION: This unsaturated polyester resin composition comprises an unsaturated polyester resin, a polymerizing monomer and fine expandable particles as indispensable components. A fiber-reinforced plastic molded article is prepared by using an unsaturated polyester resin material for molding which comprises a reinforcing fiber as well as the unsaturated polyester resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an unsaturated polyester resin composition, an unsaturated polyester resin molding material, a fiber-reinforced plastic molded product, and a method for producing the same.

[0002]

2. Description of the Related Art Unsaturated polyester resin molded articles have excellent mechanical strength, heat resistance, water resistance, chemical resistance and high productivity. For example, bathtubs, bathroom panels, water tank panels, septic tanks, Widely used for kitchen countertops and the like. In recent years, unsaturated polyester sheet molding compounds (SMC) or bulk molding compounds (BMC) have been spotlighted as plastic materials for automobiles. Among them, molded products having a surface smoothness comparable to that of metal parts (for example, iron plate) by reducing the shrinkage of molded products are used for main outer plates such as trunk lits, roofs, fenders and exteriors such as spoilers. It has also been used for parts. In order to reduce the shrinkage of the molded article, it is necessary to add a thermoplastic resin such as a saturated polyester resin, polyvinyl acetate, or polymethyl methacrylate as a low shrinkage agent. The technique of obtaining a molded product having surface smoothness that can be used for an automobile outer panel has not been put to practical use. This low-shrinkage agent is a thermoplastic resin or the like, and when added, when the temperature of a molded article rises, it causes a decrease in rigidity. If it is added to a component that is baked and painted at high temperatures, such as an automobile outer panel, it causes a problem that deformation occurs during baking. Therefore, as a guide, the retention ratio of the flexural modulus at 80 ° C. to the room temperature is 70%.
It is desirable that this is the case. In addition, the thermoplastic resin used for the low-shrinkage agent is often incompatible with the unsaturated polyester resin.Therefore, when the resin composition and the molding material are stored for a long period of time, phase separation may occur and the resin may become unusable. Many. Alternatively, when molding a molding material to which a low-shrinkage agent is added, since the low-shrinkage agent often causes separation in the mold and deteriorates the appearance, selection of strict optimal molding conditions is important. . Thus, while having the property that the rigidity of the molded article does not decrease even at high temperatures, and the property that the surface flatness of the molded article surface is equivalent to that of an automobile outer panel, the storage stability is good for a long time, There is no technology to obtain a material with a large selection range of conditions, which is a major technical problem.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been developed in such a manner that the surface smoothness can be brought to a level that can be used for automobile outer panels without adding a so-called low shrinkage agent. It is intended to provide an unsaturated polyester resin composition, an unsaturated polyester resin molding material, a fiber-reinforced plastic molded article using the molding material, and a method for producing the same.

[0004]

That is, the present invention relates to an unsaturated polyester resin composition containing an unsaturated polyester resin, a polymerizable monomer, and foamable fine particles as essential components. The present invention also relates to an unsaturated polyester resin molding material comprising the above unsaturated polyester resin composition and reinforcing fibers. Further, the present invention relates to a method for producing a fiber-reinforced plastic molded article using the molding material.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The unsaturated polyester resin composition 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. Containing unsaturated polyester resin, polymerizable monomer and foamable fine particles.
In the present invention, α, β-unsaturated polybasic acid or an anhydride thereof, which is a raw material for synthesizing an unsaturated polyester resin, includes:
For example, α, β-unsaturated dibasic acids or anhydrides thereof, for example, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, anhydrides thereof and the like can be mentioned. 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, the α, β-unsaturated polybasic acid or its anhydride is preferably at least 40 mol% of the polybasic acid component. When the amount of α, β-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%, and 50 to 80 mol%.
Particularly preferred is 70 mol%. As the saturated polybasic acid or anhydride used in combination, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, hexahydrophthalic acid Examples include acid, hexahydrophthalic anhydride, glutaric acid, adipic acid, sebacic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, dimer acid, succinic acid, azelaic acid, and rosin-maleic acid adduct. These may be used in combination of two or more.

[0006] Polyhydric alcohols as 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, when the polybasic acid component is 1, the polyhydric alcohol is used in the range of 1 to 1.3,
It is more preferable to use in the range of 1.03 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 an unsaturated polyester resin, a conventionally known method can be used. Further, as the polymerizable monomer used in the present invention, for example, styrene, chlorostyrene, divinylbenzene, tert-butylstyrene, styrene derivatives such as styrene bromide, methyl methacrylate, ethyl methacrylate, ethyl acrylate, Alkyl esters of methacrylic acid or acrylic acid such as butyl acrylate, hydroxyalkyl esters of methacrylic acid or acrylic acid such as ethyl β-hydroxymethacrylate and β-hydroxyacrylate, diallyl phthalate, acrylamide, phenylmaleimide and the like. . Also, ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate,
Polyfunctional methacrylic acid or acrylic acid esters such as trimethylpropane trimethacrylate can also be used.

The expandable fine particles used in the present invention are those obtained by encapsulating a hydrocarbon or a halogen compound in a polymer capsule mainly comprising polyvinylidene chloride, polyacrylonitrile, polyphenylene oxide and the like. "Microsphere" (trade name) and "Expancel" (trade name) of Nippon Philite Co., Ltd. can be used. The compounding amount of the expandable fine particles is 3 to 40% by weight, preferably 5 to 20% by weight, more preferably 5 to 40% by weight based on the total amount of the unsaturated polyester resin and the polymerizable monomer.
１５15% by weight. If it is less than 3% by weight, the smoothness of the surface of the molded article is poor, and if it is more than 40% by weight, physical properties such as strength are reduced.

An unsaturated polyester resin composition is prepared by blending an unsaturated polyester resin, a polymerizable monomer and foamable fine particles, and optionally adding a polymerization inhibitor and the like. 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. If the amount of the unsaturated polyester resin exceeds 80 parts by weight, the viscosity may be so high that it may be difficult to apply or 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 added,
For storage stability, it is preferable to contain 0.05% by weight or more.

[0010] The unsaturated polyester resin composition of the present invention comprises an organic peroxide such as t-butyl perbenzoate, which is added as a curing agent to a general unsaturated polyester resin composition, if necessary, and a filler; Thickeners, release agents, pigments and the like can be added. 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. Examples of the filler include calcium carbonate, aluminum hydroxide, and clay. The amount of the filler used is determined in consideration of the physical properties such as the strength of the molded article, the viscosity of the unsaturated polyester resin composition, and the fluidity, but based on the total amount of the unsaturated polyester resin and the polymerizable monomer. It is preferably 100 to 200% by weight, particularly preferably 105 to 150% by weight. If the amount of the filler is too small, sedimentation may occur, and if the amount of the filler is too large, the viscosity tends to be high and stirring tends to be difficult. Thickeners include magnesium or calcium oxides or hydroxides. 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. Examples of the release agent include fatty acids such as stearic acid and mystyric acid, metal salts of fatty acids such as zinc stearate and calcium stearate, and surfactants such as phosphate esters. The amount of the release agent is preferably 1 to 10% by weight, more preferably 2 to 4% by weight, based on the total amount of the unsaturated polyester resin and the polymerizable monomer. 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 unsaturated polyester resin composition of the present invention is further made to contain a reinforcing fiber to obtain a fiber-reinforced molding material. At this time, the unsaturated polyester resin contains a thickener and a curing agent as essential components. In addition, fillers,
It preferably contains a release agent and a polymerization inhibitor. As the reinforcing fiber, glass fiber, carbonate fiber, aramid fiber, polyvinyl alcohol-based fiber and the like can be used, and glass fiber is generally used. These reinforcing materials are used in the form of continuous fibers, woven fabrics, non-woven fabrics, etc., and it is preferable to use a roving-shaped material cut to an appropriate length (in the case of SMC, cut to 20 to 30 mm, In the case of (1), a material cut to 6 to 15 mm) is preferably used. In producing the fiber-reinforced molding material, the amount of the reinforcing fiber used depends on the required strength, but is in the range of 15 to 35% by weight based on the total amount of the unsaturated polyester resin and the polymerizable monomer. Is preferred.

The fiber-reinforced molding material of the present invention, for example, SM
C and BMC can be manufactured using an ordinary SMC manufacturing apparatus or BMC manufacturing apparatus, respectively. SMC
In the case of, apply the compounding resin on the release film so as to have a uniform thickness, and uniformly spread a reinforcing material such as glass fiber cut to a predetermined length on this, and further compound on this Another resin-coated film is superimposed such that the scattered reinforcing material is sandwiched by the compounded resin, and this is wound up in a roll and, if necessary, matured to form a sheet-like molding material. it can. When a thickener is added, it is preferable to heat the mixture to a temperature of room temperature to 60 ° C. for aging. As the release film, a polyethylene film, a polypropylene film, or the like can be used. BMC
In the case of (1), the reinforcing fibers are mixed with the unsaturated polyester resin composition, but there is no particular limitation on the mixing order of the components used in these.

The unsaturated polyester resin composition of the present invention is used in an amount of from 20 to 80 parts by weight of an unsaturated polyester resin, from 20 to 80 parts by weight, so that the surface smoothness of the molded article becomes a level that can be used as an automobile outer panel. Of the foamable fine particles 10 per 100 parts by weight of the polymerizable monomer
It is blended at a ratio of about 70 parts by weight. The unsaturated polyester resin composition into which such various compounds are blended can be prepared by, for example, using glass fiber (having a fiber diameter of 8 to 2) using ordinary means and equipment.
By impregnating reinforcing fibers (for example, 0 μm and having a length of about 1/4 to 4 inches) into a molding material such as a sheet-like sheet molding compound (SMC) or a bulk-like bulk molding compound (BMC) Can be. The glass fiber is usually blended in an amount of 10 to 40% by weight based on the total amount of the resin composition. The molding material of the present invention can be molded by heating and compression (temperature: 110 to 180 ° C.) or injection molding (temperature: 110 ° C. to 180 ° C.) in a mold and cured. During molding,
In view of the amount of expansion when the molding material containing the expandable fine particles is foamed, a certain amount of voids are formed in the molding cavity without completely filling the molding material before foaming. In the compression molding, the cavity in the mold cavity is formed by molding without applying pressure to the molding material from the beginning, and by applying pressure to the molding material first, the molding material fills the entire molding cavity. After that, there is a manufacturing method in which the pressure is removed again, the mold is slightly opened, and the mold is floated.In the case of injection molding, the mold is completely closed and the amount of molding material to be injected is reduced more than usual. By reducing the number, voids are created in the mold cavity.

[0014]

EXAMPLES Compositions shown in Table 1 (materials are in parts by weight)
Adjusted the seat molding compound (SMC). A predetermined amount of each SMC is charged into a mold (mold) cavity, and the mold is molded at a molding pressure of 1.5 MPa and a mold temperature of 14 MPa.
The mold was pressed at 5 ° C. for 5 seconds, and the mold was raised to a position where the plate thickness became 5 mm. The mold was allowed to stand at a pressure of 0 Pa and a mold temperature of 145 ° C. for 5 minutes under a predetermined condition to obtain a plate (250 × 250 × 5).
mm). Comparative Example 1 shows a molded article obtained by the same molding method without using the expandable fine particles which are an essential component of the present invention. Comparative Example 2 had the same composition as Comparative Example 1, but was compression-molded at approximately 10 MPa during molding in the same manner as general SMC molding. In the comparative example, a foaming fine particle, which is an essential component, was not blended, a commonly used low-shrinking agent was blended, and molded at 10 MPa. Table 1 shows the results of measuring the surface smoothness of the molded product of the adjusted SMC. The surface smoothness was determined by visual inspection, and if the same level as that of the steel plate for the car body outer panel, ○, the lowest level that is inferior to the steel sheet but usable for the car outer panel was Δ, and ×, if it could not be used at all, did. The SMC long-term storage stability was evaluated by visually and touching the SMC after storing it in a 30 ° C. environment for 90 days, and then seeing out the low-shrinkage agent on the surface of the material. O was observed when no exudation was observed and was equivalent to that immediately after production, O was slight when exudation was observed, but was evaluated as acceptable. The flexural strength and the flexural modulus of the molded product were measured by cutting a test piece from the molded product and rigging it according to JIS-K7055A.

[0015]

[Table 1] In Table 1, unsaturated polyester resin: Polyset 9120 (trade name, manufactured by Hitachi Chemical Co., Ltd.) Low shrinkage agent (polyvinyl acetate): 40% by weight styrene solution of ASR-M4 (trade name, manufactured by Denki Kagaku Kogyo KK) Expandable fine particles : Trade name, manufactured by Nippon Philite Co., Ltd., Expancel 091DU80 t-butyl perbenzoate: trade name, manufactured by Nippon Yushi Co., Ltd. Perbutyl Z parabenzoquinone: manufactured by Seiko Chemical Co., Ltd. Release agent: manufactured by Nippon Yushi Co., Ltd. Name zinc stearate Calcium carbonate: Nitto Powder Chemical Co., Ltd. product name NS400 Thickener: Kyowa Chemical Industry Co., Ltd. product name Kyowa Mag 20 Glass fiber: Nitto Boseki Co., Ltd. product name RS450A-7
82AM (1 inch length cut product)

[0016]

According to the present invention, the molding material has extremely excellent long-term storage stability, and a molded article using the same has an extremely smooth surface smoothness that can be used for an automobile outer panel, and At high temperatures, it is possible to supply molded articles with little reduction in rigidity and without fear of deformation, which is particularly effective in the field of automobile outer panels.

Continued on the front page F-term (reference) 4F074 AA37 AA49 AA69 AA77 AD01 AD02 AD11 AD13 AE06 BA35 BA42 CA23 CA24 CA31 CB62 CB84 CC10Y DA08 DA09 DA59 4F204 AA13L AA21L AA41K AB02 AB11 AB12 AB16 AB21 AB25 AC04 FA01 AG20 A4A BE023 BG102 CF221 CF231 CF261 CG003 CH072 CL063 DL008 EA007 EA036 EB007 EB126 EB136 EH076 EH146 EP016 EU026 FA043 FA048 FD010 FD140 FD160 FD340 GN00

Claims (9)

[Claims] 1. An unsaturated polyester resin composition comprising, as essential components, an unsaturated polyester resin, a polymerizable monomer and foamable fine particles. 2. An unsaturated polyester resin, a polymerizable monomer,
An unsaturated polyester resin molding material containing foamable fine particles and reinforcing fibers as essential components. 3. The unsaturated polyester resin molding material according to claim 2, which is a sheet or bulk molding material. 4. The unsaturated polyester resin molding material according to claim 2, wherein the reinforcing fibers are glass fibers. 5. The foamable fine particle is one wherein a hydrocarbon or a halogen compound is encapsulated in a polymer capsule.
5. The unsaturated polyester resin molding material according to any one of 4. 6. A fiber-reinforced plastic molded article obtained by molding and curing the unsaturated polyester molding material according to claim 2. 7. After the unsaturated polyester resin molding material according to any one of claims 2 to 5 is inserted into a molding cavity, compression molding is started with a slightly opened molding die, and the compression molding is started by the expansion force of the molding material. A method for producing a fiber-reinforced plastic molded product in which a molding material is molded so as to fill the entire molding cavity. 8. Inserting the unsaturated polyester resin molding material according to any one of claims 2 to 5 into a molding cavity, filling the molding material into the molding cavity by clamping pressure, and then removing the molding die. A method of manufacturing fiber-reinforced plastic molded products that are slightly opened and compression molded. 9. An unsaturated polyester resin molding material according to any one of claims 2 to 5, which is injected into the closed mold cavity in an amount smaller than the cavity volume.
A method for producing a fiber-reinforced plastic molded article, which is injection-molded so that the entire molding cavity is filled with the molding material by the expansion force of the molding material.