JP2013159715A - Unsaturated polyester resin material and fiber-reinforced plastic-molded material obtained by molding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an unsaturated polyester resin material having properties suitable as a molding material though an unsaturated polyester resin to be obtained from itaconic acid is contained therein.SOLUTION: An unsaturated polyester resin material contains: an unsaturated polyester resin to be produced by reacting polycarboxylic acid and polyol; and styrene. The polycarboxylic acid contains itaconic acid. The polyol contains propylene glycol and dipropylene glycol. A ratio of the dipropylene glycol to the total amount of the propylene glycol and the dipropylene glycol is ≤25 mol%.

Description

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

  Unsaturated polyester resins which are thermosetting resins are widely used for molding materials such as sheet mold compounds (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 (see Patent Document 1).

  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.

JP 2012-1606 etc.

  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 a molding material, the cured product of the unsaturated polyester resin is also required to have a sufficiently high hardness so that the molded product can withstand demolding and movement.

  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 contains an unsaturated polyester resin produced by a reaction between a polycarboxylic acid and a polyol, and styrene.
The polycarboxylic acid contains itaconic acid;
The polyol contains propylene glycol and dipropylene glycol;
The ratio of the dipropylene glycol to the total amount of the propylene glycol and the dipropylene glycol is 25 mol% or less.

  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 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 product of the 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.

  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 dipropylene glycol. For this reason, when the polycarboxylic acid component reacts with the polyol component, good reactivity is maintained, and the gelation of the unsaturated polyester resin as a product is suppressed. 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.

  Furthermore, since the ratio of dipropylene glycol with respect to the total amount of propylene glycol and dipropylene glycol is 25 mol% or less, the glass of the resin cured material produced | generated by the radical polymerization reaction of the resin component which consists of unsaturated polyester resin and styrene The transition temperature is kept high. For this reason, when molding materials, such as a fiber reinforced plastic molding material obtained using an unsaturated polyester resin material, are molded to obtain a molded product, the hardness of the molded product becomes sufficiently high. For this reason, the handleability at the time of demolding, moving and the like 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, and therefore, the handleability when the molded product is removed from the mold, moved, etc. is 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.

  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.

  The lower limit of the proportion of dipropylene glycol relative to the total amount of propylene glycol and dipropylene glycol is not particularly limited, but in order to particularly improve the weight average molecular weight of the unsaturated polyester resin, the proportion of dipropylene glycol is 5 mol. % Or more is preferable. In order to effectively improve the glass transition temperature of the cured resin, the proportion of dipropylene glycol is preferably 10 mol% or less. That is, the ratio of dipropylene glycol to the total amount of propylene glycol and dipropylene glycol is preferably in the range of 5 mol% to 25 mol%, and more preferably in the range of 5 mol% to 10 mol%. .

  The higher the ratio of the total amount of propylene glycol and dipropylene glycol 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 further suppressed. The ratio of the total amount of propylene glycol and dipropylene glycol to the entire polyol is preferably 50 mol% or more. For example, the ratio of the total amount of propylene glycol and dipropylene glycol relative to the entire polyol may be in the range of 50 mol% or more and 95 mol% or less. Further, it is particularly preferable that the polyol is composed only of propylene glycol and dipropylene glycol.

  In the present embodiment, when the polyol contains a compound other than propylene glycol and dipropylene glycol, 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.

  In this way, when synthesizing the unsaturated polyester resin, good reactivity is maintained in this embodiment even though itaconic acid is used. Moreover, it becomes difficult to gelatinize the unsaturated polyester resin to produce | generate.

  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.

  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 raw material containing an unsaturated polyester resin material, the SMC is easily thickened by curing. For this reason, the handling property of SMC improves. Further, it is more preferable that the weight average molecular weight is 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 obtaining a molded product using this unsaturated polyester resin material, first, using the unsaturated polyester resin material, a fiber reinforced plastic molding material such as SMC is prepared, and this fiber reinforced plastic molding material is molded. A molded product can be obtained.

  The raw material used to obtain the fiber reinforced plastic molding material can include an unsaturated polyester resin material and fibers. Although it does not restrict | limit especially as a fiber, A glass fiber is mentioned.

  Moreover, the raw material for obtaining the fiber reinforced plastic molding material may further contain various additives as required. Additives that can be included in the raw materials include cross-linking agents, curing agents, low shrinkage agents, thickeners, fillers, colorants, polymerization inhibitors, polymerization retarders, curing accelerators, viscosity reducers, and dispersion modifiers. And mold release agents.

  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, a composition for molding is prepared by blending ingredients excluding fibers in the raw material. 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. The molding composition is impregnated into the fiber, and then the composition and the fiber are sandwiched between two films and further pressed with a roller or the like as necessary. Thereby, the sheet body comprised from the fiber and the molding composition impregnated in this fiber is formed between two films. 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 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. Into this flask, put itaconic acid (made by Iwata Chemical Industry Co., Ltd.), propylene glycol (made by Wako Pure Chemical Industries, Ltd.), and dipropylene glycol (made by Wako Pure Chemical Industries, Ltd.) in the amounts shown in Table 1. Thus, a mixed solution was obtained. 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 any Examples and Comparative Examples, no gelation of the unsaturated polyester resin material was observed.

  The ratio of styrene to the total amount of unsaturated polyester resin and styrene in the unsaturated polyester resin material was 40% by mass in Examples 1-4, 30% by mass in Example 5, and 50% by mass in Example 6. The amount of styrene used was adjusted so that

  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 6, unsaturated polyester resin materials containing high molecular weight resin components were obtained without gelation. Particularly in Examples 1 to 3, the weight average molecular weight of the resin component reached 10,000 or more. On the other hand, although high molecular weight was possible in Comparative Example 2, the weight average molecular weight of the resin component was small in Comparative Example 1.

  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. For this reason, even when trying to measure the molecular weight by GPC, the filter was clogged during preliminary filtration, making it impossible to measure.

[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 1 Heated for hours, 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. The cured product was heated at 120 ° C. for 2 hours with a thermostat and then slowly 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 6, the glass transition temperature of the cured product was 150 ° C. or higher. On the other hand, in Comparative Example 1, the glass transition temperature was high, but in Comparative Example 2, the glass transition temperature was low.

[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 “◯”. On the other hand, a case where the protective sheet was firmly attached to the SMC and could not be peeled off, and a case where the SMC was deformed when the protective sheet was peeled off were evaluated as “x”.

  As a result, as shown in Table 1 below, in Examples 1 to 3 and 5 and Comparative Example 2, the handleability was good. For this reason, in Examples 1-3, 5 and Comparative Example 2, it can be evaluated that SMC is sufficiently thickened by curing. In addition, the evaluation of the handling property in Example 6 is low because SMC was prepared with the same composition for evaluation as Example 1 and the like despite the high proportion of styrene in the unsaturated polyester resin material. It is inferred that the stickiness has occurred. That is, the reason why the evaluation of handling property in Example 6 is low is not because the thickening property is low, but because the composition of SMC does not match the composition of the unsaturated polyester resin material.

  According to these evaluation results, in Examples 1 to 4, it was possible to increase the molecular weight of the resin component, and the glass transition temperature of the cured resin component was high. Furthermore, in Examples 1 to 3, the handling properties of SMC were 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 glass transition temperature of the cured resin component was low.

Claims (5)

Containing unsaturated polyester resin produced by the reaction of polycarboxylic acid and polyol, and styrene,
The polycarboxylic acid contains itaconic acid;
The polyol contains propylene glycol and dipropylene glycol;
The unsaturated polyester resin material whose ratio of the said dipropylene glycol with respect to the total amount of the said propylene glycol and the said dipropylene glycol is 25 mol% or less. 2. The unsaturated polyester resin material according to claim 1, 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 1 or 2, wherein a weight-average molecular weight of a resin component comprising the unsaturated polyester resin and the styrene is 10,000 or more. The unsaturated polyester resin material according to any one of claims 1 to 3, 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 1 to 4 and fibers into a sheet shape.