JPWO2013183196A1 - Unsaturated polyester resin, unsaturated polyester resin material, and fiber-reinforced plastic molding material formed by molding unsaturated polyester resin material - Google Patents

Abstract

The unsaturated polyester resin according to the present invention is an unsaturated polyester resin produced by a reaction between a polycarboxylic acid and a polyol. The polycarboxylic acid contains itaconic acid. The polyol contains propylene glycol and 1,3-propanediol. The ratio of the 1,3-propanediol to the total amount of the propylene glycol and the 1,3-propanediol is 40 mol% or less.

Description

  The present invention relates to an unsaturated polyester resin, an unsaturated polyester resin material, and a fiber-reinforced plastic molding material formed by molding an unsaturated polyester resin material.

  For example, Japanese Patent Publication No. 2012-1606 proposes using an unsaturated polyester resin as a thermosetting resin for a molding material such as a sheet molding compound (SMC). As the unsaturated dicarboxylic acid that is a raw material of the unsaturated polyester resin, maleic anhydride, maleic acid, fumaric acid and the like are used.

  On the other hand, in recent years, from the viewpoint of promoting resource recycling, it has been required to use plant-derived materials industrially. For this reason, it is required to use plant-derived materials as raw materials for unsaturated polyester resins. It has been. In particular, itaconic acid has attracted attention as a plant-derived unsaturated dicarboxylic acid.

  However, when the present inventors examined the use of itaconic acid as a raw material for unsaturated polyester resin, itaconic acid is less ester reactive than maleic anhydride, maleic acid, fumaric acid, etc. there were. For this reason, particularly when itaconic acid reacts with a high molecular weight polyol, there are problems that the reaction time becomes remarkably long and it is difficult to increase the molecular weight of the unsaturated polyester resin. On the other hand, when itaconic acid and propylene glycol are reacted, the reactivity does not decrease greatly, but the product obtained by the reaction is easily gelled, so that it is difficult to increase the molecular weight of the product.

  Therefore, it has been difficult to apply an unsaturated polyester resin obtained from itaconic acid to a molding material such as SMC.

  Furthermore, when an unsaturated polyester resin is applied to the molding material, the hardness of the cured product formed from the unsaturated polyester resin is sufficiently high so that the molded product can withstand the impact of demolding, moving, etc. Is also required.

  The present invention has been made in view of the above-mentioned reasons, and the object of the present invention is to provide an unsaturated polyester resin having characteristics suitable as a molding material despite containing an unsaturated polyester resin obtained from itaconic acid. It is providing the material and the fiber reinforced plastic molding material obtained by using this unsaturated polyester resin material.

The unsaturated polyester resin material according to the present invention is an unsaturated polyester resin produced by a reaction between a polycarboxylic acid and a polyol,
The polycarboxylic acid contains itaconic acid;
The polyol contains propylene glycol and 1,3-propanediol, and the ratio of the 1,3-propanediol to the total amount of the propylene glycol and the 1,3-propanediol is 40 mol% or less.

  The unsaturated polyester resin material according to the present invention preferably contains the unsaturated polyester resin and styrene.

  In the unsaturated polyester resin material according to the present invention, it is preferable that a glass transition temperature of a resin cured product generated by radical polymerization reaction of a resin component composed of the unsaturated polyester resin and the styrene is 150 ° C. or higher.

  In the unsaturated polyester resin material in the present invention, it is preferable that the resin component composed of the unsaturated polyester resin and the styrene has a weight average molecular weight of 10,000 or more.

  In the unsaturated polyester resin material of the present invention, it is preferable that the ratio of the styrene is in the range of 30% by mass or more and 50% by mass or less with respect to the total amount of the unsaturated polyester resin and the styrene.

  The fiber-reinforced plastic molding material according to the present invention is formed by molding a raw material containing the unsaturated polyester resin material and fibers into a sheet shape.

  The unsaturated polyester resin according to the present invention contains itaconic acid and propylene glycol by containing 1,3-propanediol in a proportion of 40 mol% or less with respect to the total amount of propylene glycol and 1,3-propanediol. Can also reduce the gelation of the obtained unsaturated polyester resin.

  The unsaturated polyester resin material according to the present invention is synthesized with good reactivity, the high molecular weight of the unsaturated polyester resin material is easy, the gelation of the unsaturated polyester resin material is suppressed, and the unsaturated polyester resin material is further suppressed. Since the glass transition temperature of the cured resin component in the resin material is increased, the unsaturated polyester resin material has characteristics suitable as a molding material.

  Moreover, since the fiber reinforced plastic molding material which concerns on this invention is obtained using the above unsaturated polyester resin materials, it has the characteristic suitable as a molding material.

  Hereinafter, an embodiment of the invention will be described.

  The unsaturated polyester resin material according to this embodiment contains an unsaturated polyester resin and styrene.

  Unsaturated polyester resin is produced | generated when polycarboxylic acid and a polyol react. Here, polycarboxylic acid means a compound having a plurality of carboxyl groups in one molecule. Polyol means a compound having a plurality of hydroxyl groups in one molecule.

  When the unsaturated polyester resin is synthesized, an ester-forming derivative of polycarboxylic acid may be used instead of or together with polycarboxylic acid. An ester-forming derivative of a polycarboxylic acid is a derivative that can form an ester by reacting with a polyol. Examples of the ester-forming derivative of polycarboxylic acid include polycarboxylic acid anhydrides, compounds of polycarboxylic acid and compounds capable of transesterification with polyol.

  Further, when the unsaturated polyester resin is synthesized, an ester-forming derivative of a polyol may be used instead of or together with the polyol. An ester-forming derivative of a polyol is a derivative that can form an ester by reacting with a polycarboxylic acid. Examples of the ester-forming derivative of a polyol include a compound which is an ester of a polyol and can undergo an ester exchange reaction with a polycarboxylic acid.

  In this embodiment, the polycarboxylic acid contains itaconic acid. For this reason, the use of plant-derived materials is promoted, and therefore resource circulation is promoted. In order to further promote resource circulation, it is preferable that the ratio of itaconic acid to the whole polycarboxylic acid is higher. The ratio of itaconic acid to the whole polycarboxylic acid is preferably 50 mol% or more. For example, the ratio of itaconic acid to the whole polycarboxylic acid may be in the range of 50 mol% or more and 95 mol% or less. Further, it is particularly preferable if the polycarboxylic acid is composed of itaconic acid alone.

  In this embodiment, when the polycarboxylic acid contains a compound other than itaconic acid, for example, the polycarboxylic acid is an unsaturated polycarboxylic acid such as maleic acid or fumaric acid, an aliphatic saturated such as sebacic acid, succinic acid, or adipic acid. Aromatic polycarboxylic acids such as polycarboxylic acid, phthalic acid, isophthalic acid and terephthalic acid may also be included. Among these compounds, only one type may be used or two or more types may be used in combination.

  In this embodiment, the polyol contains propylene glycol and 1,3-propanediol. For this reason, when the polycarboxylic acid component and the polyol component react, good reactivity between the hydroxyl group of the polyol and the carboxyl group of the polycarboxylic acid is maintained. In addition, in the unsaturated polyester resin that is the product, unreacted hydroxyl groups and carboxyl groups are reduced, thereby suppressing the gelation of the unsaturated polyester resin.

  Specifically, propylene glycol has a molecular structure in which two hydroxyl groups are branched. For this reason, when the polycarboxylic acid component is reacted with propylene glycol, the unsaturated polyester resin is easily gelled due to unreacted hydroxyl groups and carboxyl groups. On the other hand, when the polyol contains propylene glycol and 1,3-propanediol, unreacted hydroxyl groups and carboxyl groups are reduced as described above, and gelation of the unsaturated polyester resin is reduced.

  For this reason, the production efficiency of the unsaturated polyester resin is improved, and the high molecular weight of the unsaturated polyester resin is facilitated. Further, the unsaturated polyester resin and styrene constitute an unsaturated polyester resin material, and in the cured resin produced by radical polymerization reaction of the resin component of the unsaturated polyester resin material, the unsaturated polyester resin contains itaconic acid. However, it has an excellent glass transition temperature.

  For this reason, when molding materials, such as a fiber reinforced plastic molding material obtained using the resin composition containing an unsaturated polyester resin material and a fiber, are molded, the hardness of the molded product is sufficiently increased. For this reason, in the manufacturing process of a molded product, the molded product has excellent resistance to impacts due to demolding, movement, and the like. Therefore, the handleability of the molded product is improved. The glass transition temperature of the cured resin is particularly preferably 150 ° C. or higher. In this case, the hardness of the molded product is particularly high. For this reason, the molded product has excellent resistance to impacts due to demolding, moving, etc., and handling properties are further improved. The upper limit of the glass transition temperature is not particularly limited, but if the glass transition temperature becomes too high, the molded product may become brittle. Therefore, the glass transition temperature is preferably in the range of 150 ° C. or higher and 200 ° C. or lower. The glass transition temperature of this cured resin is easily adjusted by changing the ratio of propylene glycol and 1,3-propanediol, for example.

  Specifically, the ratio of propylene glycol and 1,3-propanediol is adjusted according to the total amount of carboxyl groups of the polycarboxylic acid contained in the unsaturated polyester resin material.

  As a method for preparing the cured resin and a method for measuring the glass transition temperature, for example, the method described in the column “Evaluation of glass transition temperature of cured resin component” in the examples described later is employed.

  Furthermore, since the ratio of 1,3-propanediol to the total amount of propylene glycol and 1,3-propanediol is 40 mol% or less, the polycarboxylic acid reacts with the polyol to produce an unsaturated polyester resin. The gelation of the unsaturated polyester resin as a product is suppressed. Itaconic acid is less likely to cause homopolymerization. For this reason, unsaturated polyester resin is obtained easily.

When the proportion of 1,3-propanediol is more than 40 mol% based on the total amount of propylene glycol and 1,3-propanediol, an alkylene group (— (CH ₂ ) _n contained in 1,3-propanediol -; Where n is a positive integer) is relatively long, and the resulting unsaturated polyester resin is considered to be easily crystallized. For this reason, the molecule | numerator of unsaturated polyester resin becomes easy to become physically entangled, and it is thought that unsaturated polyester resin becomes easy to gelatinize as a result.

  The lower limit of the proportion of 1,3-propanediol is not particularly limited, but in order to particularly improve the weight average molecular weight of the unsaturated polyester resin, it is 5 with respect to the total amount of propylene glycol and 1,3-propanediol. It is preferably at least mol%. When the proportion of 1,3-propanediol is less than 5 mol%, the effect of blending 1,3-propanediol may not be obtained.

  Further, the ratio of 1,3-propanediol to the total amount of propylene glycol and 1,3-propanediol is preferably in the range of 5 to 40 mol%, more preferably in the range of 5 to 30 mol%. .

  The higher the ratio of the total amount of propylene glycol and 1,3-propanediol to the total polyol, the better the reactivity between the polycarboxylic acid component and the polyol component and the more the gelation of the unsaturated polyester resin is suppressed. . The ratio of the total amount of propylene glycol and 1,3-propanediol to the entire polyol is preferably 50 mol% or more. For example, the ratio of the total amount of propylene glycol and 1,3-propanediol to the entire polyol may be in the range of 50 mol% to 95 mol%. It is also preferred that the polyol consists only of propylene glycol and 1,3-propanediol.

  However, the above-described ratio is an example, and the ratio of the entire polyol may be adjusted according to the total amount of carboxyl groups of the polycarboxylic acid. That is, in order to obtain a good unsaturated polyester resin, the ratio of the entire polyol is preferably set so that the carboxyl group of the polycarboxylic acid remaining during the reaction and the hydroxyl group of the polyol are reduced.

  In the present embodiment, when the polyol contains a compound other than propylene glycol and 1,3-propanediol, for example, the polyol may contain an aliphatic polyol, an aromatic polyol, or the like. Examples of the aliphatic polyol include ethylene glycol, butylene glycol, triethylene glycol, neopentyl glycol, hexamethylene glycol, trimethylene glycol, glycerin, hydrogenated bisphenol A, and the like. Examples of the aromatic polyol include bisphenol A and bisphenol S. Among these compounds, only one type may be used or two or more types may be used in combination.

  An unsaturated polyester resin is obtained by reacting the polycarboxylic acid and the polyol. In this case, the polycarboxylic acid and the polyol can be reacted by adopting a known method. For example, the polycarboxylic acid and the polyol can be reacted by heating a mixed liquid containing the polycarboxylic acid and the polyol in an inert atmosphere. The equivalent ratio of polyol to polycarboxylic acid used in the synthesis of unsaturated polyester resin (molar ratio of hydroxyl group to carboxyl group) is preferably in the range of 0.7 to 1.5.

As described above, an ester-forming derivative of polycarboxylic acid may be used instead of or together with polycarboxylic acid, and an ester-forming derivative of polyol instead of or together with polyol. May be used.

Thus, when synthesizing the unsaturated polyester resin, good reactivity can be obtained even though itaconic acid is used in the present embodiment. Moreover, the unsaturated polyester resin to produce | generate becomes difficult to gelatinize.

  The unsaturated polyester resin material preferably contains styrene. Thereby, the said unsaturated polyester resin material is comprised so that it may react between itaconic acid contained in polycarboxylic acid, and styrene.

  Moreover, it is preferable that the ratio of the styrene in unsaturated polyester resin material is the range of 30 to 50 mass% with respect to the total amount of unsaturated polyester resin and styrene. When this proportion is 30% by mass or more, an excessive increase in the viscosity of the unsaturated polyester resin material is suppressed. For this reason, productivity of unsaturated polyester resin material improves. Moreover, the excessive fall of the viscosity of unsaturated polyester resin material is suppressed as this ratio is 50 mass% or less. Therefore, particularly when SMC is produced, good thickening of the unsaturated polyester resin material is ensured.

  Here, the SMC exemplified above is composed of a resin composition. This resin composition includes fibers and an unsaturated polyester resin material, and is formed into a sheet by being sandwiched between two films. The SMC is formed into a molded product by hot-pressure molding in a mold. Examples of the fiber include glass fiber and carbon fiber.

  As described above, in this embodiment, it is easy to increase the molecular weight of the unsaturated polyester resin. In particular, the weight average molecular weight of the resin component composed of the unsaturated polyester resin and styrene in the unsaturated polyester resin material is 10,000. The above is preferable. In this case, particularly when SMC is obtained using a molding composition containing an unsaturated polyester resin material, the SMC tends to thicken by curing. For this reason, the handling property of SMC improves. The weight average molecular weight of the resin component is more preferably 10,000 or more and 800,000 or less. Moreover, it is especially preferable if this weight average molecular weight is in the range of 15,000 to 400,000.

  In addition, a cured resin is obtained from the resin component of the unsaturated polyester resin material. The glass transition temperature of the cured resin is particularly preferably 150 ° C. or higher. In this case, the hardness of the molded product is particularly high. For this reason, the molded product has excellent resistance to impacts due to demolding, moving, etc., and handling properties are further improved. The upper limit of the glass transition temperature is not particularly limited, but if the glass transition temperature is too high, the molded product may be brittle. Therefore, the glass transition temperature of the cured resin product is preferably in the range of 150 ° C. or higher and 200 ° C. or lower.

  In obtaining a molded product using this unsaturated polyester resin material, first, a resin composition is prepared using the unsaturated polyester resin material and fibers. Then, a fiber reinforced plastic molding material such as SMC is prepared from this resin composition. This fiber-reinforced plastic molding material is preferably supplied into a mold and subjected to a treatment such as hot pressing. Thereby, a molded product can be obtained from the fiber reinforced plastic molding material.

  Here, the fiber is not particularly limited, and examples thereof include glass fiber and carbon fiber.

  The raw material (resin composition) used to obtain the fiber-reinforced plastic molding material can contain an unsaturated polyester resin material and fibers. Although it does not restrict | limit especially as a fiber, Glass fiber, carbon fiber, etc. are mentioned.

  The fiber-reinforced plastic molding material is preferably formed by molding a resin composition containing an unsaturated polyester resin material and fibers into a sheet shape.

  Moreover, the raw material (resin composition) for obtaining a fiber reinforced plastic molding material may further contain various additives as needed. Additives that the raw material (resin composition) can contain include a crosslinking agent, a curing agent, a low shrinkage agent, a thickener, a filler, a colorant, a polymerization inhibitor, a polymerization retarder, a curing accelerator, and a thinning agent. Agents, dispersion modifiers, release agents and the like.

  Examples of the crosslinking agent include styrene, vinyl toluene, vinyl acetate, diallyl phthalate, triallyl cyanurate, acrylic acid ester, methacrylic acid ester, methyl methacrylate, and ethyl methacrylate. Among these compounds, only one type may be used or two or more types may be used in combination.

  Examples of the curing agent include peroxydicarbonates such as t-amyl peroxyisopropyl carbonate, ketone peroxides, hydroperoxides, diacyl peroxides, peroxyketals, dialkyl peroxides, and peroxyesters. And alkyl peresters. Among these compounds, only one type may be used or two or more types may be used in combination.

  Examples of the low shrinkage agent include polystyrene, polymethyl methacrylate, cellulose acetate butyrate, polycaprolactan, polyvinyl acetate, polyethylene, and polyvinyl chloride. Among these compounds, only one type may be used or two or more types may be used in combination.

  Examples of the thickener include magnesium oxide, calcium oxide, magnesium hydroxide, calcium hydroxide, tolylene diisocyanate, diphenylmethane diisocyanate, and the like. Among these compounds, only one type may be used or two or more types may be used in combination.

  Examples of the filler include calcium carbonate, aluminum hydroxide, silica, mica, and glass beads. Among these compounds, only one type may be used or two or more types may be used in combination.

  Examples of the colorant include inorganic pigments and organic pigments. Among these, only 1 type may be used or 2 or more types may be used together.

  First, the composition for shaping | molding is prepared by mix | blending the component except a fiber in a raw material (resin composition). For example, a molding composition is prepared by blending an unsaturated polyester resin material, a low shrinkage agent, a crosslinking agent, a filler, a thickener, and the like. When fibers are blended in the molding composition, the fibers are impregnated with the resin component of the molding composition. Thereby, a resin composition is obtained. Subsequently, an unsaturated polyester resin material (molding composition) and a resin composition composed of fibers are sandwiched between two films and further pressed by a roller or the like as necessary. Thereby, between two films, the resin composition comprised from a fiber and the molding composition impregnated in this fiber is formed in a sheet | seat body. This sheet body is allowed to stand for a certain period of time at a predetermined temperature, for example, 35 ° C. to 50 ° C. Thereby, the sheet body is cured and thickened. Thereby, SMC (fiber reinforced plastic molding material) is obtained.

(Preparation of unsaturated polyester resin material)
A 500-mL four-necked separable flask equipped with a stirrer, a thermometer, a cooling pipe (for dehydration), and a nitrogen gas purge pipe was prepared. In this flask, itaconic acid (produced by Iwata Chemical Co., Ltd.), propylene glycol (produced by Wako Pure Chemical Industries, Ltd.), and 1,3-propanediol (produced by Wako Pure Chemical Industries, Ltd.) in the amounts shown in Table 1 were used. Was added to obtain a mixed solution. Subsequently, while purging the flask with nitrogen and stirring the mixed solution, the mixed solution was gradually heated to 150 ° C. with a mantle heater. Subsequently, the temperature of the mixed solution was kept in the range of 150 to 165 ° C. for 1 hour or longer. Subsequently, after the mixed solution was gradually heated, the temperature of the mixed solution was kept in a temperature range of 200 to 210 ° C. Thus, while maintaining the temperature of the mixed solution, the acid value of the reaction product in the mixed solution was measured in a timely manner. The acid value was measured by titration using an ethanol solution of potassium hydroxide. When the acid value reached about 60, heating was stopped and the mixture was allowed to cool. When the temperature of the mixture decreases to about 115 ° C., 0.1 g of a polymerization inhibitor (hydroquinone, manufactured by Wako Pure Chemical Industries, Ltd.) and the amount of styrene (Wako Pure Chemical Industries, Ltd.) shown in Table 1 are contained in the mixture. Made). Subsequently, the mixture was allowed to cool to 60 ° C. or lower while stirring. Thereby, an unsaturated polyester resin material was obtained.

  In Examples 1 to 5 and Comparative Examples 1 and 2, the amount of styrene used was adjusted so that the ratio of styrene to the total amount of unsaturated polyester resin and styrene in the unsaturated polyester resin material was 40% by mass. It was adjusted. In Table 1, the amount of each compound is shown as a molar ratio.

  The weight average molecular weight of the resin component in this unsaturated polyester resin material was measured by gel permeation chromatography (GPC). In the measurement, model number HLC-8220GPC manufactured by Tosoh Corporation is used as a GPC apparatus, TSKgel Guardcolumn SuperHZ-L, TSKgel SuperHZ3000, TSKgel SuperHZ2000, and TSKgel SuperHZ1000 manufactured by Tosoh Corporation are used as columns, and Kurashiki Spin is used as a pre-filter. Chromatodisc 13N 0.45 manufactured by Co., Ltd. was used.

  As a result, as shown in Table 1 below, in Examples 1 to 5, the weight average molecular weight of the resin component was 10,000 or more, but the resin component containing the high molecular weight resin component was not gelled. A saturated polyester resin material was obtained. On the other hand, in Comparative Example 1, gelation did not occur, but the weight average molecular weight of the resin component was small. In Comparative Example 2, the unsaturated polyester resin material was gelled. For this reason, the unsaturated polyester resin material becomes insoluble in styrene, and even if an attempt is made to measure the molecular weight by GPC, the filter is clogged during preliminary filtration, making measurement impossible.

  In Comparative Example 1, when the reaction was advanced until the acid value reached 50 for increasing the molecular weight, the unsaturated polyester resin material was gelled. As a result, the molecular weight is not measurable.

[Evaluation of glass transition temperature of cured resin component]
A casting mold was manufactured using a SUS plate (1 mmt) and a silicon rubber spacer (3 mmt).

  100 parts by weight of unsaturated polyester resin material, 0.5 part by weight of a curing accelerator (6% cobalt naphthenate, manufactured by Wako Pure Chemical Industries, Ltd.), 1 part by weight of a curing agent (manufactured by NOF Corporation, product name Parmec N), defoaming A mixed material was obtained by sequentially mixing 0.1 parts by mass of an agent (manufactured by Big Chemie Japan, product number A550). This mixed material was poured into a casting mold and allowed to stand at room temperature for 16 hours. Then, using a thermostat, heat at 70 ° C. for 1 hour, then heat at 80 ° C. for 1 hour, then heat at 90 ° C. for 1 hour, then heat at 100 ° C. for 1 hour, then at 110 ° C. Heated for 1 hour, followed by heating at 120 ° C. for 2 hours, followed by slow cooling to room temperature. The cured product thus obtained was removed from the casting mold. This cured product was heated with a thermostat at 120 ° C. for 2 hours and then gradually cooled.

  Subsequently, the glass transition temperature of the cured product was measured using a viscoelastic spectrometer (manufactured by SII Nanotechnology, Inc., model number DMS6100).

  As a result, as shown in Table 1 below, in Examples 1 to 5, the glass transition temperature of the cured product was 150 ° C. or higher. In Comparative Example 2, since the unsaturated polyester resin material was gelled, no cured product was obtained, and therefore evaluation was impossible.

[Production of SMC sheet and evaluation of handling properties]
80 parts by mass of unsaturated polyester resin material, 15 parts by mass of low shrinkage agent (manufactured by Showa Denko KK, product number M-5590-2), 5 parts by mass of crosslinking agent (styrene monomer, manufactured by Wako Pure Chemical Industries, Ltd.), inorganic filling A mixture was obtained by mixing 150 parts by mass of an agent (product number SL101, manufactured by Shiraishi Co., Ltd.). Moreover, it increases by mixing 1 weight part of thickener (Kyowa Chemical Co., Ltd. make, brand name Kyomag # 40) and 5 weight part of low shrinkage agent (made by Showa Denko KK, product number M-5590-2). A viscous material was obtained. Subsequently, the molding composition was obtained by mixing the mixture and the thickening material at a mass ratio of 250: 6.

  This molding composition was impregnated into glass fiber (manufactured by Nitto Boseki Co., Ltd., product number RS280PB-549). The mass ratio between the molding composition and the glass fiber was 75:25. Subsequently, the molding composition and the glass fiber were sandwiched between two protective films made of polypropylene, and further pressed by a roller to form a sheet body between the two protective films. This sheet was cured at 40 ° C. for 24 hours to obtain SMC.

  The handling property of the SMC sheet was evaluated based on the ease of peeling when the protective sheet was peeled from the SMC. That is, the case where the protective sheet could be removed from the SMC was evaluated as “good”. On the other hand, the case where the protective sheet was firmly attached to the SMC and could not be peeled off, and the case where the SMC was deformed when the protective sheet was peeled off were evaluated as “bad”.

  As a result, as shown in Table 1 below, in Examples 1 to 5, the handleability was good. For this reason, in Examples 1-5, it can be evaluated that SMC was sufficiently thickened by curing. On the other hand, in Comparative Example 1, since the SMC is soft, the protective sheet is difficult to peel off from the SMC, the surface of the SMC becomes sticky even if it is forcibly removed, and the SMC is easily deformed, so that the SMC is transferred to the mold. It was difficult. In Comparative Example 2, since the unsaturated polyester resin material was gelled, SMC was not obtained, and therefore evaluation was impossible.

これらの評価結果によると、実施例１〜５では、いずれも樹脂成分の高分子量化が可能であり、また、樹脂成分の硬化物のガラス転移温度が高いものであり、更にＳＭＣのハンドリング性が良好であった。これに対し、比較例１では樹脂成分の高分子量化が困難であり、比較例２では不飽和ポリエステル樹脂材料がゲル化してしまった。

According to these evaluation results, in Examples 1 to 5, it is possible to increase the molecular weight of the resin component, the glass transition temperature of the cured resin component is high, and the handling properties of SMC are further improved. It was good. In contrast, in Comparative Example 1, it was difficult to increase the molecular weight of the resin component, and in Comparative Example 2, the unsaturated polyester resin material was gelled.

Claims (6)

An unsaturated polyester resin produced by a reaction between a polycarboxylic acid and a polyol,
The polycarboxylic acid contains itaconic acid;
The polyol contains propylene glycol and 1,3-propanediol;
The unsaturated polyester resin whose ratio of the said 1, 3- propanediol with respect to the total amount of the said propylene glycol and the said 1, 3- propanediol is 40 mol% or less. An unsaturated polyester resin material comprising the unsaturated polyester resin according to claim 1 and styrene. The unsaturated polyester resin material according to claim 2, wherein a glass transition temperature of a resin cured product produced by radical polymerization reaction of a resin component comprising the unsaturated polyester resin and the styrene is 150 ° C or higher. The unsaturated polyester resin material according to claim 2 or 3, wherein the resin component comprising the unsaturated polyester resin and the styrene has a weight average molecular weight of 10,000 or more. The unsaturated polyester resin material according to any one of claims 2 to 4, wherein a ratio of the styrene is in a range of 30 to 50 mass% with respect to a total amount of the unsaturated polyester resin and the styrene. A fiber-reinforced plastic molding material obtained by molding a raw material containing the unsaturated polyester resin material according to any one of claims 2 to 5 and a fiber into a sheet shape.