Production method of unsaturated polyester resin cured product

Abstract

To provide a new production method of an unsaturated polyester resin cured product.SOLUTION: A production method of an unsaturated polyester resin cured product includes a reaction step of reacting phthalic acid ester having an unsaturated bond at a terminal with alkyd.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing a cured unsaturated polyester resin. [Background technology]

[0002] Cured unsaturated polyester resins have high durability and are used in a variety of fields, for example, as matrix resins for fiber-reinforced plastics.

[0003] A cured unsaturated polyester resin can be obtained by reacting an alkyd with a crosslinkable monomer (for example, Patent Document 1). Generally, styrene is used as the crosslinkable monomer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 04-285629 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a novel method for producing a cured unsaturated polyester resin. [Means for solving the problem]

[0006] The present specification discloses the following method for producing a cured unsaturated polyester resin.

[0007] Item 1. A method for producing a cured unsaturated polyester resin, comprising a reaction step of reacting a phthalic acid ester having an unsaturated bond at a terminal with an alkyd.

[0008] Item 2. The method for producing a cured unsaturated polyester resin according to Item 1, wherein the phthalic acid ester has unsaturated bonds at both ends.

[0009] Item 3. The method for producing a cured unsaturated polyester resin according to Item 1 or 2, wherein the phthalate ester is a decomposition product of a cured unsaturated polyester resin.

[0010] Item 4. The method for producing a cured unsaturated polyester resin according to any one of Items 1 to 3, wherein the phthalate ester is a compound having a structural portion derived from compound (X) on both sides of a structural portion derived from phthalic acid, and the compound (X) is a compound having a hydroxyl group and an unsaturated bond different from the double bond contained in an aromatic ring.

[0011] Item 5. The method for producing a cured unsaturated polyester resin according to Item 4, wherein the compound (X) is ethylene glycol monoallyl ether or hydroxyethyl methacrylate.

[0012] Item 6. The method for producing a cured unsaturated polyester resin according to any one of Items 1 to 5, wherein the reaction step is a step of reacting the phthalate ester, the alkyd, and a compound (Y) having a hydroxyl group and an unsaturated bond different from the double bond contained in an aromatic ring.

[0013] Item 7. The method for producing a cured unsaturated polyester resin according to any one of Items 1 to 6, wherein the reaction step is a step of reacting the phthalate ester, the alkyd, and a compound (Y) having a hydroxyl group and an unsaturated bond different from the double bond contained in an aromatic ring, and the compound (Y) and the compound (X) are the same type of compound. Effect of the Invention

[0014] According to the present invention, a novel method for producing a cured unsaturated polyester resin can be provided. [Brief description of the drawings]

[0015] [Figure 1]FIG. 1 is a schematic diagram showing an example of a chemical reaction that proceeds in a decomposition step in a production method for a phthalate ester (a decomposition product of a cured unsaturated polyester resin). [Diagram 2] FIG. 2 is a schematic diagram showing a first example of a chemical reaction that proceeds in a reaction step in a method for producing a cured unsaturated polyester resin according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a schematic diagram showing a second example of a chemical reaction that proceeds in a reaction step in a method for producing a cured unsaturated polyester resin according to one embodiment of the present invention. [Figure 4] FIG. 4(a) shows the chemical structural formula of the phthalate ester (compound (XPX)) obtained in Example 1, and FIG. 4(b) shows the spectrum obtained by 1H-NMR measurement of the phthalate ester (compound (XPX)) obtained in Example 1. [Diagram 5] FIG. 5 is an IR spectrum of the phthalic acid ester (compound (XPX)) obtained in Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention will be described in detail below.

[0017] (Method of producing cured unsaturated polyester resin) The method for producing a cured unsaturated polyester resin according to the present invention includes a reaction step of reacting a phthalic acid ester having an unsaturated bond at a terminal with an alkyd.

[0018] Conventionally, cured unsaturated polyester resins have been obtained by reacting an alkyd with a crosslinkable monomer (e.g., styrene). Conventionally, phthalic acid esters have not been used as the crosslinkable monomers to be reacted with the alkyd. The present inventors have found that when a phthalic acid ester having an unsaturated bond at its terminal is used, the reaction between the phthalic acid ester and the alkyd proceeds smoothly, and a cured unsaturated polyester resin can be obtained. That is, the present inventors have found a new method for producing a cured unsaturated polyester resin.

[0019] First, the components that can be used in the present invention will be described.

[0020] <Phthalate esters with unsaturated bonds at the terminals> In the method for producing the cured unsaturated polyester resin, a phthalic acid ester having an unsaturated bond at a terminal (hereinafter, sometimes abbreviated as phthalic acid ester) is used. The phthalic acid ester may be used alone or in combination of two or more kinds.

[0021] From the viewpoint of achieving a more satisfactory reaction between the phthalate ester and the alkyd, it is preferable that the phthalate ester has a double bond at the terminal.

[0022] From the viewpoint of achieving a more satisfactory reaction between the phthalate ester and the alkyd, the phthalate ester preferably has unsaturated bonds at both ends, and more preferably has double bonds at both ends.

[0023] From the viewpoint of achieving a more favorable reaction between the phthalate ester and the alkyd, it is preferred that the phthalate ester is a compound having a structural portion derived from compound (X) on both sides of a structural portion derived from phthalic acid, and that the compound (X) is a compound having a hydroxyl group and an unsaturated bond other than the double bond contained in the aromatic ring.

[0024] The compound (X) has a hydroxyl group. The compound (X) has an unsaturated bond different from the double bond contained in the aromatic ring. Hereinafter, in this specification, the "unsaturated bond different from the double bond contained in the aromatic ring" may be referred to as "unsaturated bond (X)". Therefore, the compound (X) has a hydroxyl group and an unsaturated bond (X). Only one type of the compound (X) may be used, or two or more types may be used in combination.

[0025] The compound (X) may have only one hydroxyl group, may have two, may have two or more, may have three, may have three or more, may have five or less, may have four or less, or may have three or less hydroxyl groups.

[0026] The compound (X) may or may not have an aromatic ring. The compound (X) may or may not have a double bond contained in the aromatic ring.

[0027] The compound (X) may have only one unsaturated bond (X), or may have two, two or more, three, three or more, five or less, four or less, or three or less.

[0028] The unsaturated bond (X) is preferably a double bond. The compound (X) preferably has a double bond.

[0029] Examples of the unsaturated bond (X) include an unsaturated bond (double bond) contained in an allyl group and an unsaturated bond (double bond) contained in a (meth)acryloyl group.

[0030] The compound (X) is preferably liquid at 20° C. That is, the compound (X) preferably has a melting point lower than 20° C. and a boiling point higher than 20° C. In this case, the components can be well mixed in the mixing step in the production method for a phthalate ester (decomposition product of a cured unsaturated polyester resin) described below.

[0031] The boiling point of the compound (X) is preferably 95° C. or higher, more preferably 100° C. or higher, and even more preferably 150° C. or higher. In this case, heating under reflux can be performed well in the decomposition step in the production method of phthalic acid ester (decomposition product of cured unsaturated polyester resin) described later. The boiling point of the compound (X) may be 300° C. or lower, or 250° C. or lower.

[0032] The compound (X) preferably has an unsaturated bond (unsaturated bond (X)) at a terminal. When the compound (X) has an unsaturated bond at a terminal, the compound (X) may also have an unsaturated bond at a portion other than the terminal, or may have an unsaturated bond only at the terminal.

[0033] The compound (X) preferably has a double bond at its terminal, and more preferably has a structure represented by the following formula (1): The structure represented by the following formula (1) is a structure having a double bond at its terminal.

[0034] [ka]

[0035] In the above formula (1), R represents a hydrogen atom or a methyl group, and * represents the bonding position to other atoms. In the above formula (1), R may be a hydrogen atom or a methyl group.

[0036] The molecular weight of the compound (X) may be 75 or more, 100 or more, 1000 or less, 500 or less, 300 or less, 200 or less, or 150 or less.

[0037] The compound (X) preferably has an allyl group or a (meth)acryloyl group. In this case, a phthalic acid ester having an unsaturated bond at the end can be obtained well. The allyl group and the (meth)acryloyl group have a structure represented by the above formula (1). The (meth)acryloyl group is an acryloyl group or a methacryloyl group.

[0038] Examples of the compound (X) having an allyl group include ethylene glycol monoallyl ether (2-allyloxyethanol) and allyl alcohol (2-propen-1-ol).

[0039] Examples of the compound (X) having an acryloyl group include ethylene glycol monoacrylate (2-hydroxyethyl acrylate), 4-hydroxybutyl acrylate, polyethylene glycol monoacrylate, and polypropylene glycol monoacrylate.

[0040] Examples of the compound (X) having a methacryloyl group include hydroxyethyl methacrylate (ethylene glycol methacrylate or 2-hydroxyethyl methacrylate), p-hydroxyphenyl methacrylate (4-hydroxyphenyl methacrylate), glycerin monomethacrylate, polyethylene glycol monomethacrylate, hydroxypropyl methacrylate, polypropylene glycol monomethacrylate, and hydroxyphenyl methacrylate.

[0041] The compound (X) is preferably ethylene glycol monoallyl ether or hydroxyethyl methacrylate, in which case the reaction between the phthalic acid ester and the alkyd can be more effectively carried out.

[0042] From the viewpoint of recycling the cured unsaturated polyester resin, the phthalate ester is preferably a decomposition product of the cured unsaturated polyester resin. The cured unsaturated polyester resin has high durability and is used in various fields, but recycling technology has not been put to practical use, and most of the cured unsaturated polyester resin is disposed of as waste by landfill treatment. By using the phthalate ester, which is a decomposition product of the cured unsaturated polyester resin, the cured unsaturated polyester resin can be reproduced. However, the phthalate ester does not have to be a decomposition product of the cured unsaturated polyester resin. The phthalate ester, which is not a decomposition product of the cured unsaturated polyester resin, can be obtained, for example, by reacting phthalic acid with the compound (X).

[0043] A method for obtaining the above phthalic acid ester, which is a decomposition product of a cured unsaturated polyester resin, will be described below.

[0044] The phthalate ester, which is a decomposition product of a cured unsaturated polyester resin, can be obtained, for example, by a method for producing a phthalate ester comprising the following mixing step and the following decomposition step. The phthalate ester obtained by this method usually has a structural portion derived from compound (X) on both sides of a structural portion derived from phthalic acid.

[0045] Mixing step: a step of obtaining a mixture containing a substance including a cured unsaturated polyester resin, a compound (X) having a hydroxyl group and an unsaturated bond different from the double bond contained in the aromatic ring, and a metal catalyst.

[0046] Decomposition step: a step of reacting the cured unsaturated polyester resin contained in the above substance with the compound (X) to decompose the cured unsaturated polyester resin.

[0047] From the viewpoint of obtaining the above-mentioned phthalic acid ester, the cured unsaturated polyester resin contained in the above-mentioned substance preferably has a structural portion derived from phthalic acid.

[0048] From the viewpoint of recycling, the above-mentioned substance preferably includes waste containing the above-mentioned cured unsaturated polyester resin. The above-mentioned waste includes waste after using a molded article (product) containing the above-mentioned cured unsaturated polyester resin, and defective products generated during the production of a molded article (product) containing the above-mentioned cured unsaturated polyester resin.

[0049] The substance may contain only the cured unsaturated polyester resin, or may contain the cured unsaturated polyester resin and a component other than the cured unsaturated polyester resin.

[0050] Examples of components other than the cured unsaturated polyester resin include glass fiber, carbon fiber, organic fiber, satin fabric, aramid fiber, boron fiber, silica sand, colorant, calcium carbonate, calcium carbide, talc, aluminum hydroxide, thickener, internal release agent, reactive diluent, low shrinkage agent, antioxidant, modifier, flame retardant, and antibacterial agent. The glass fiber may be contained in the form of a glass mat, a glass cloth, or chopped strands used in sheet molding compound (SMC). Only one of the components may be used, or two or more of them may be used in combination. The material may, for example, contain the cured unsaturated polyester resin and glass fiber, the cured unsaturated polyester resin and silica sand, or the cured unsaturated polyester resin, glass fiber, and silica sand.

[0051] The content of the cured unsaturated polyester resin in 100% by weight of the above substance may be 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. The content of the cured unsaturated polyester resin in 100% by weight of the above substance may be 100% by weight or less, 90% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, or 20% by weight or less.

[0052] The compound (X) that can be used in the method for producing a phthalic acid ester includes the compound (X) described above.

[0053] The metal catalyst is a catalyst containing a metal atom. The metal catalyst may be used alone or in combination of two or more kinds.

[0054] The metal catalyst is not particularly limited as long as it can catalyze the chemical reaction between the cured unsaturated polyester resin and the compound (X).

[0055] The metal catalyst includes metal salts, metal hydroxides, metal oxides, and the like.

[0056] Examples of metals contained in the metal catalyst include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, titanium, zirconium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, silver, palladium, zinc, aluminum, gallium, and tin.

[0057] From the viewpoint of further increasing the decomposition efficiency of the cured unsaturated polyester resin material, the metal catalyst is preferably a metal salt, a metal hydroxide or a metal oxide, and more preferably tripotassium phosphate, sodium hydroxide or sodium ethoxide.

[0058] In the mixing step, other components such as a polymerization inhibitor, a crosslinkable monomer, and a diluting solvent may be used. The other components may be used alone or in combination of two or more.

[0059] The mixing step is carried out, for example, by putting the substance, the compound (X), and the metal catalyst into a container. The mixing step is preferably a step of adding the substance to the compound (X) in the container.

[0060] In the mixture, the substance, the compound (X) and the metal catalyst may or may not be uniformly mixed. For example, in the mixture, the substance may sink to the bottom of the container.

[0061] The substance mixed in the mixing step is preferably a pulverized waste material containing the cured unsaturated polyester resin. In this case, the contact area between the substance and the compound (X) can be increased, so that the decomposition reaction can proceed more efficiently.

[0062] In the mixture, the content of the substance relative to 100 parts by weight of the compound (X) is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and preferably 100 parts by weight or less, more preferably 50 parts by weight or less. When the content of the substance is equal to or more than the lower limit and equal to or less than the upper limit, the phthalate ester, which is a decomposition product of the cured unsaturated polyester resin, can be obtained satisfactorily.

[0063] In the mixture, the content of the cured unsaturated polyester resin in the substance relative to 100 parts by weight of the compound (X) is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and preferably 100 parts by weight or less, more preferably 50 parts by weight or less. When the content of the cured unsaturated polyester resin is equal to or more than the lower limit and equal to or less than the upper limit, the phthalate ester, which is a decomposition product of the cured unsaturated polyester resin, can be obtained satisfactorily.

[0064] The content of the metal catalyst in 100% by weight of the mixture is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 10% by weight or less, more preferably 5% by weight or less. When the content of the metal catalyst is equal to or more than the lower limit and equal to or less than the upper limit, the phthalate ester, which is a decomposition product of the cured unsaturated polyester resin, can be obtained satisfactorily.

[0065] When the mixture contains the polymerization inhibitor, the content of the polymerization inhibitor in 100% by weight of the mixture is preferably 0.005% by weight or more, more preferably 0.01% by weight or more, and preferably 0.5% by weight or less, more preferably 0.1% by weight or less. When the content of the polymerization inhibitor is equal to or more than the lower limit and equal to or less than the upper limit, the phthalic acid ester, which is a decomposition product of the cured unsaturated polyester resin, can be obtained satisfactorily.

[0066] The decomposition step may be carried out substantially simultaneously with the mixing step. For example, the substance is added to the heated compound (X), so that the decomposition step proceeds substantially simultaneously with the mixing step.

[0067] In the decomposition step, an ester exchange reaction can be caused to proceed between the cured unsaturated polyester resin and the compound (X). The decomposition step can produce the phthalic acid ester, which is a decomposition product of the cured unsaturated polyester resin.

[0068] FIG. 1 is a schematic diagram showing an example of a chemical reaction that proceeds in a decomposition reaction in a manufacturing method of a phthalate ester (a decomposition product of a cured unsaturated polyester resin). FIG. 1(a) shows each component before the decomposition process, and FIG. 1(b) shows each component after the decomposition process. FIG. 1(a) shows a cured unsaturated polyester resin made from fumaric acid (F), phthalic acid (P), glycol (G), and styrene (S). FIG. 1(a) also shows a compound (X) having a double bond at the end. FIG. 1(a) also shows a metal catalyst (C).

[0069] The decomposition product of the cured unsaturated polyester resin decomposed in the decomposition step contains the following compounds 1) to 3), for example, as shown in FIG. 1(b).

[0070] 1) Phthalate ester (XPX) having a structural portion derived from the above compound (X) on both sides of a structural portion derived from phthalic acid (P).

[0071] The phthalate ester (XPX) has double bonds at both ends derived from the double bond contained in the compound (X).

[0072] 2) Glycol (G).

[0073] 3) A compound (XFX) having a structural portion derived from fumaric acid (F), a structural portion derived from styrene (S), and a structural portion derived from the above compound (X).

[0074] After the decomposition step, the unreacted compound (X) also remains in the vessel, and the metal catalyst (C) also remains in the vessel.

[0075] In the decomposition step, the mixture is preferably heated. The decomposition step is preferably a heating reflux step.

[0076] The heating temperature in the above decomposition step can be appropriately changed depending on the type of compound (X).

[0077] In the decomposition step, the cured unsaturated polyester resin may be decomposed while stirring the mixture.

[0078] The decomposition step is preferably carried out at normal pressure (1 atm). However, when it is desired to increase the decomposition rate of the cured unsaturated polyester resin material, the decomposition step may be carried out at a low pressure. The decomposition step is preferably carried out at a pressure of 0.1 MPa or more, and preferably at a pressure of 0.2 MPa or less. In the method for producing the phthalate ester, which is the decomposition product of the cured unsaturated polyester resin material, the decomposition reaction can proceed even under normal pressure to low pressure conditions such as the pressure conditions mentioned above. Therefore, there is no need to use a pressure-resistant container or the like, and the phthalate ester can be easily obtained.

[0079] <Alkyd> In the method for producing the cured unsaturated polyester resin, an alkyd is used. As the alkyd, a conventionally known alkyd can be used. The alkyd can be obtained, for example, by reacting a saturated polybasic acid, an unsaturated polybasic acid, and a polyhydric alcohol.

[0080] Examples of the saturated polybasic acid include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, adipic acid, sebacic acid, HET acid (chlorendic acid), and tetrabromophthalic anhydride, etc. The saturated polybasic acid may be used alone or in combination of two or more.

[0081] Examples of the unsaturated polybasic acid include fumaric acid, maleic anhydride, itaconic acid, etc. The unsaturated polybasic acid may be used alone or in combination of two or more kinds.

[0082] Examples of the polyhydric alcohol include glycol and bisphenol. Examples of the glycol include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, polyethylene glycol, tripropylene glycol, polypropylene glycol, neopentyl glycol, 1,3-butanediol, 1,6-hexanediol, and dibromo neopentyl glycol. Examples of the bisphenol include hydrogenated bisphenol A and bisphenol A propylene oxide adduct. The polyhydric alcohol may be used alone or in combination of two or more.

[0083] <Compound (Y) Having a Hydroxyl Group and an Unsaturated Bond Different from the Double Bond Contained in the Aromatic Ring> In the method for producing the cured unsaturated polyester resin, a compound (Y) having a hydroxyl group and an unsaturated bond different from the double bond contained in the aromatic ring may or may not be used. The reaction step is preferably a step of reacting the phthalate ester, the alkyd, and a compound (Y) having a hydroxyl group and an unsaturated bond different from the double bond contained in the aromatic ring.

[0084] The compound (Y) has a hydroxyl group. The compound (Y) has an unsaturated bond different from the double bond contained in the aromatic ring. The compound (Y) may be the compound (X) described above. The compound (Y) may be used alone or in combination of two or more kinds.

[0085] The compound (Y) and the compound (X) are preferably the same type of compound. The compound (Y) may be, for example, the compound (X) obtained after the decomposition step in the method for producing a phthalic acid ester, which is a decomposition product of a cured unsaturated polyester resin.

[0086] <Other ingredients> In the method for producing the cured unsaturated polyester resin, other components may be used in addition to the above-mentioned components (phthalic acid ester, alkyd, and compound (Y)). Examples of the other components include a crosslinkable monomer different from both compound (X) and compound (Y), a curing agent, and a curing accelerator.

[0087] In the method for producing a cured unsaturated polyester resin, a crosslinking monomer different from both the compound (X) and the compound (Y) may be used. The reaction step may be a step of reacting the phthalate ester, the alkyd, and a crosslinking monomer different from both the compound (X) and the compound (Y). The reaction step may be a step of reacting the phthalate ester, the alkyd, the compound (Y), and a crosslinking monomer different from both the compound (X) and the compound (Y).

[0088] The crosslinkable monomer different from both the compound (X) and the compound (Y) may be styrene, etc. The crosslinkable monomer different from both the compound (X) and the compound (Y) may be used alone or in combination of two or more kinds.

[0089] The crosslinkable monomer different from both compound (X) and compound (Y) is preferably styrene.

[0090] In the method for producing the cured unsaturated polyester resin, a curing agent may be used, a curing accelerator may be used, or a curing agent and a curing accelerator may be used. In the reaction step, a curing agent may be used, a curing accelerator may be used, or a curing agent and a curing accelerator may be used. As the curing agent and the curing accelerator, a curing agent and a curing accelerator that are usually used in the curing reaction of an unsaturated polyester resin can be used.

[0091] Hereinafter, the method for producing a cured unsaturated polyester resin of the present invention will be described with reference to the drawings.

[0092] FIG. 2 is a schematic diagram showing a first example of a chemical reaction that proceeds in a reaction step in a method for producing a cured unsaturated polyester resin according to one embodiment of the present invention. In FIG. 2(a), a phthalate ester (XPX) having a structural portion derived from a compound (X) on both sides of a structural portion derived from phthalic acid (P) is shown. Also, in FIG. 2(a), an alkyd made from fumaric acid (F), phthalic acid (P), and glycol (G) is shown. As shown in FIG. 2(b), the fumaric acid (F) portion of the alkyd is crosslinked by the phthalate ester (XPX) in the reaction step, whereby a cured unsaturated polyester resin can be produced.

[0093] FIG. 3 is a schematic diagram showing a second example of a chemical reaction that proceeds in a reaction step in a method for producing a cured unsaturated polyester resin according to an embodiment of the present invention. In FIG. 3(a), a phthalate ester (XPX) having a structural portion derived from a compound (X) on both sides of a structural portion derived from a phthalic acid (P) is described. Also, in FIG. 3(a), an alkyd made from fumaric acid (F), phthalic acid (P), and glycol (G) is described. Also, in FIG. 3(a), a compound (Y) is described. As shown in FIG. 3(b), the fumaric acid (F) portion of the alkyd is crosslinked by the phthalate ester (XPX) or by the compound (Y) in the reaction step, thereby producing a cured unsaturated polyester resin. It is preferable that the compound (Y) contains the compound (X) used in the method for producing a phthalate ester (decomposition product of a cured unsaturated polyester resin) described above. The compound (Y) may be the compound (X) contained in the filtrate obtained by filtering the liquid after the decomposition step.

[0094] In the reaction step, the phthalic acid ester is reacted in an amount of preferably 50 parts by weight or more, more preferably 75 parts by weight or more, and more preferably 200 parts by weight or less, and more preferably 150 parts by weight or less, per 100 parts by weight of the alkyd, whereby a cured unsaturated polyester resin can be obtained more satisfactorily.

[0095] In the reaction step, the compound (Y) is reacted preferably in an amount of 50 parts by weight or more, more preferably 75 parts by weight or more, more preferably 200 parts by weight or less, and more preferably 150 parts by weight or less, relative to 100 parts by weight of the alkyd. In this case, the unsaturated polyester resin cured material can be obtained more satisfactorily.

[0096] The reaction temperature in the reaction step is not particularly limited as long as the alkyd and the phthalic acid ester react with each other. The reaction temperature in the reaction step may be 20°C or higher, 80°C or higher, 140°C or higher, 300°C or lower, 250°C or lower, or 220°C or lower. Before the reaction step, the raw material or the molding die may be preheated to promote curing. After the reaction step, the cured product or the molding die may be heated to promote curing.

[0097] (Unsaturated polyester resin cured product) The unsaturated polyester resin cured product obtained by the method for producing a cured unsaturated polyester resin of the present invention is a reaction product of a phthalic acid ester having an unsaturated bond at a terminal and an alkyd. The unsaturated polyester resin cured product obtained by the method for producing a cured unsaturated polyester resin of the present invention may be a reaction product of a phthalic acid ester having an unsaturated bond at a terminal, an alkyd, and a compound (Y) having a hydroxyl group and an unsaturated bond different from the double bond contained in the aromatic ring. The unsaturated polyester resin cured product has a structural part derived from the phthalic acid ester. The unsaturated polyester resin cured product has a structural part derived from the alkyd. The unsaturated polyester resin cured product may have a structural part derived from the compound (Y). In the cured unsaturated polyester resin, the structural part derived from the alkyd is crosslinked by the structural part derived from the phthalic acid ester. In the cured unsaturated polyester resin, the structural part derived from the alkyd may be crosslinked by the structural part derived from the compound (Y).

[0098] The present invention will be specifically described below by way of examples and comparative examples, but the present invention is not limited to the following examples.

[0099] The following materials were prepared:

[0100] (Substances containing cured unsaturated polyester resin) Substance A: Unsaturated polyester resin hardened material Substance B: A material containing a cured unsaturated polyester resin and glass fiber (the ratio (weight ratio) of the cured unsaturated polyester resin to components other than the cured product is 7:15 (cured product:components other than the cured product)).

[0101] The cured unsaturated polyester resin contained in the substances A and B has a structural portion derived from phthalic acid.

[0102] (Compound (X)) Ethylene glycol monoallyl ether (EGMA) Hydroxyethyl methacrylate (HEMA)

[0103] (Compound not corresponding to compound (X)) Xylene Ethylene glycol (EG) Diethylene glycol (DEG) Benzyl alcohol (BzOH)

[0104] (Metal catalyst) Potassium phosphate (K3PO4) Sodium Ethoxide (EtONa)

[0105] (Polymerization inhibitor) Phenothiazine

[0106] (Examples 1 to 5) <Method of manufacturing phthalate esters (decomposition products of cured unsaturated polyester resins)> Mixing process: The components shown in the table below were placed in a container equipped with a mantle heater in the amounts shown in the table below to obtain a mixture (mixed liquid).

[0107] Decomposition process: The mantle heater was set to the temperature shown in the table below, and the mixture was heated (refluxed) for the time and pressure shown in the table below. The mixture was stirred during the decomposition process. In this way, the unsaturated polyester resin cured product contained in the material was reacted with the compound (X) to decompose the unsaturated polyester resin cured product.

[0108] Filtration process: The liquid containing the decomposition product of the cured unsaturated polyester resin was filtered under suction. The filtrate was distilled under reduced pressure to obtain a liquid containing the compound (X) and the compound (XPX) having a structural portion derived from the compound (X) on both sides of a structural portion derived from phthalic acid (P).

[0109] (Comparative Examples 1 to 4) The above mixing step, the above decomposition step, and the above filtration step were carried out in the same manner as in Example 1, except that the components shown in the table below were used and the conditions for the decomposition step were changed as shown in the table below.

[0110] (evaluation) (1) Confirmation of decomposition products (phthalate esters) The compound (XPX) obtained in the above filtration step was confirmed to be a phthalate ester by the following test.

[0111] (1-1) 1 H-NMR measurement From the liquid containing compound (XPX) and compound (X) obtained in the above filtration step, compound (X) was removed to obtain compound (XPX). The obtained compound (XPX) was dissolved in deuterated chloroform, and the liquid was placed in an NMR apparatus. 1 The measurement was performed using H as the measurement nucleus. The measurement was accumulated 256 times.

[0112] As a result, it was confirmed that the compound (XPX) obtained in Examples 1 to 5 was a phthalate ester having a double bond (C=C) at the terminal. Note that FIG. 4(a) shows the chemical structure of the phthalate ester (compound (XPX)) obtained in Example 1, and FIG. 4(b) shows the chemical structure of the phthalate ester (compound (XPX)) obtained in Example 1. 1The spectrum was obtained by H-NMR measurement. Peaks a to f in Fig. 4(b) correspond to the peaks of the structural portion in Fig. 4(a).

[0113] On the other hand, in Comparative Examples 1 to 4, when the liquid obtained through the above mixing step, the above decomposition step, and the above filtration step was used, a large amount of by-products was produced, and a good spectrum could not be obtained.

[0114] (1-2) IR spectrum measurement Compound (X) was removed from the solution containing compound (XPX) and compound (X) obtained in the above filtration step to obtain compound (XPX). The obtained compound (XPX) was applied to a NaCl plate, which was then placed in an IR device and measured by the transmission method. The measurement range was 4000 cm -1 ~400cm -1 From the obtained IR spectrum, it was confirmed whether or not phthalate esters were produced.

[0115] As a result, it was confirmed that the compound (XPX) obtained in Examples 1 to 5 was a phthalate ester having a double bond (C=C) at the terminal. FIG. 5 is an IR spectrum of the phthalate ester (compound (XPX)) obtained in Example 1. In FIG. 5, peak a is a peak derived from the ester bond of the phthalate ester, peak b is a peak derived from the double bond (terminal) of the phthalate ester, and peak c is a peak derived from the aromatic ring of the phthalate ester.

[0116] On the other hand, in Comparative Examples 1 to 4, when the liquid obtained through the mixing step, the decomposition step, and the filtration step was used, a large amount of by-products was produced, and a good IR spectrum could not be obtained.

[0117] (1-3) Decomposition rate of ester bonds The decomposition rate of the ester bond in the cured unsaturated polyester resin was calculated from the styrene peak and the phthalate peak in the IR spectrum obtained in the above "(1-2) IR spectrum measurement". Specifically, it was calculated by the following formula.

[0118] Decomposition rate of ester bond (%) = (1-styrene peak intensity after decomposition / styrene peak intensity before decomposition) x 100

[0119] The results are shown in the following table: In Comparative Examples 2 to 4, the amount of by-products was so large that it was not possible to calculate the decomposition rate of the ester bond.

[0120] Based on the above results, in the table below, the evaluation result for "production of phthalic acid ester" in Examples 1 to 5 is marked with "○", and the evaluation result for "production of phthalic acid ester" in Comparative Examples 1 to 5 is marked with "×".

[0121] (2) Manufacture (reproduction) of hardened unsaturated polyester resin The following experiments were carried out using the phthalic acid esters (compounds (XPX)) obtained in Examples 1 to 5.

[0122] (2-1) Experiment using styrene as a crosslinking monomer (conventional method) 55g of crosslinkable monomer (styrene), 45g of alkyd (raw materials: fumaric acid (F), phthalic acid (P) and glycol (G)), 1.0g of hardener (methyl ethyl ketone peroxide) and 0.5g of hardener accelerator (cobalt octylate) were mixed. The crosslinkable monomer (styrene) and alkyd in the resulting mixture were reacted at 20°C. As a result, a hardened unsaturated polyester resin was obtained.

[0123] (2-2) Experiment A using styrene and phthalate ester as crosslinking monomers Except for using 27.5g of styrene and 27.5g of phthalic acid ester as the crosslinkable monomers, the crosslinkable monomers (styrene and phthalic acid ester) in the mixed solution were reacted with the alkyd in the same manner as described in the above "(2-1)". As a result, the curing reaction proceeded well, and a cured unsaturated polyester resin was obtained.

[0124] (2-3) Experiment B using phthalate ester as crosslinking monomer The crosslinkable monomer (phthalic acid ester) in the mixed solution was reacted with the alkyd in the same manner as in the method described in "(2-1)" above, except that 55 g of phthalic acid ester was used as the crosslinkable monomer and the reaction temperature was changed to 80° C. As a result, the curing reaction proceeded smoothly, and a cured unsaturated polyester resin was obtained.

[0125] (2-4) Experiment C using phthalate ester, compound (X) and styrene as crosslinking monomers The crosslinkable monomer (phthalic acid ester, compound (X) and styrene) in the mixed solution was reacted with alkyd in the same manner as described in the above "(2-1)" except that 4 g of phthalic acid ester, 11 g of compound (X) and 40 g of styrene were used instead of 55 g of crosslinkable monomer (styrene) and the reaction temperature was changed to 20° C. As a result, the curing reaction proceeded well and a cured unsaturated polyester resin was obtained.

[0126] As shown in the above experiments A to C, even when phthalic acid ester was used, a good unsaturated polyester resin cured product was obtained, as in the conventional method. Based on the above results, in the table below, "○" is recorded as the evaluation result of "Production of unsaturated polyester resin cured product" in Examples 1 to 5.

[0127] Details and results are shown in Tables 1 and 2 below.

[0128] [Table 1]

[0129] [Table 2]

Claims

1. A method for producing a cured unsaturated polyester resin, comprising a reaction step of reacting a phthalic acid ester having an unsaturated bond at a terminal with an alkyd.

2. The method for producing a cured unsaturated polyester resin according to claim 1 , wherein the phthalic acid ester has unsaturated bonds at both ends.

3. The method for producing a cured unsaturated polyester resin according to claim 1 or 2, wherein the phthalate ester is a decomposition product of the cured unsaturated polyester resin.

4. the phthalate ester is a compound having a structural portion derived from compound (X) on both sides of a structural portion derived from phthalic acid, The method for producing a cured unsaturated polyester resin according to claim 1 or 2, wherein the compound (X) is a compound having a hydroxyl group and an unsaturated bond other than the double bond contained in an aromatic ring.

5. The method for producing a cured unsaturated polyester resin according to claim 4, wherein the compound (X) is ethylene glycol monoallyl ether or hydroxyethyl methacrylate.

6. 3. The method for producing a cured unsaturated polyester resin according to claim 1, wherein the reaction step is a step of reacting the phthalate ester, the alkyd, and a compound (Y) having a hydroxyl group and an unsaturated bond other than a double bond contained in an aromatic ring.

7. the reaction step is a step of reacting the phthalate ester, the alkyd, and a compound (Y) having a hydroxyl group and an unsaturated bond other than the double bond contained in an aromatic ring, The method for producing a cured unsaturated polyester resin according to claim 4, wherein the compound (Y) and the compound (X) are the same type of compound.

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