JP7613099B2 - Resin composition, molded article, and method for producing resin composition - Google Patents

Description

The present invention relates to a resin composition that is made by blending polyarylene sulfide, modified cyclodextrin, and epoxy resin, and that can produce molded articles with an excellent balance of rigidity and toughness, as well as to a molded article produced by molding the resin composition, and a method for producing the resin composition.

Polyarylene sulfide resins, such as polyphenylene sulfide resins, have properties suitable for engineering plastics, such as excellent heat resistance, flame retardancy, rigidity, chemical resistance, and electrical insulation, and are used primarily in molded products, as well as in a variety of electrical and electronic components, machine parts, and automotive parts. However, it is difficult to say that polyarylene sulfide resins are sufficiently superior in terms of toughness compared to other engineering plastics, such as polyamide resins.

Many attempts have been made to toughen polyarylene sulfide by alloying it with materials that have excellent toughness, such as elastomers (see, for example, Patent Document 1), polyesters (see, for example, Patent Document 2), and epoxy resins (see, for example, Patent Document 3), to improve its impact resistance. However, alloying with these materials often results in a decrease in the tensile strength, elastic modulus, and heat resistance of polyarylene sulfide, and the effect of improving toughness, particularly tensile elongation at break, is often limited, making it difficult to obtain a resin composition that balances the excellent inherent properties of polyarylene sulfide with toughness.

On the other hand, methods for improving the impact strength and toughness of resin compositions have been proposed, such as a resin composition obtained by reacting a polyolefin modified with an unsaturated carboxylic anhydride with a polyrotaxane having a functional group (see, for example, Patent Document 4), and a polylactic acid-based resin composition containing a polyrotaxane in which the opening of a cyclic molecule having a graft chain made of polylactic acid is enclosed by a linear molecule, and a polylactic acid resin (see, for example, Patent Document 5). In addition, Patent Document 6 proposes a method for greatly improving the toughness of polyamide by adding a polyrotaxane to the resin composition.

US5191020 publication Japanese Patent Application Publication No. 4-173671 Patent No. 4297772 JP 2013-209460 A JP 2014-84414 A International Publication No. 2016/167247

However, the polyrotaxane disclosed in Patent Document 6 has poor thermal stability, and the temperature range suitable for the production and molding of a resin composition is limited to the decomposition temperature of the polyrotaxane or lower, making it difficult to apply the polyrotaxane to polyarylene sulfide resins which have high molding temperatures.
In view of the above, an object of the present invention is to provide a resin composition which uses a modified cyclodextrin having excellent thermal stability and which is capable of producing a molded article having an excellent balance between rigidity and toughness.

In order to solve the above problems, the present invention has the following configuration.
(1) A resin composition comprising at least a polyarylene sulfide (A), a modified cyclodextrin (B), and an epoxy resin (C), wherein the polyarylene sulfide (A) is blended in an amount of 80 parts by mass or more and 99.9 parts by mass or less, and the modified cyclodextrin (B) and the epoxy resin (C) are blended in an amount of 0.1 parts by mass or more and 20 parts by mass or less in total, per 100 parts by mass of the polyarylene sulfide (A), the modified cyclodextrin (B), and the epoxy resin (C) .
(2) A resin composition comprising at least polyarylene sulfide (A), modified cyclodextrin (B), and epoxy resin (C), the resin composition having a sea-island structure consisting of a sea phase mainly composed of the polyarylene sulfide (A) and an island phase mainly composed of the modified cyclodextrin (B) and the epoxy resin (C), the average diameter of the island phase being 1 μm or less.
(3) The resin composition according to item (1) or (2), wherein the modified cyclodextrin (B) is modified with an aliphatic polyester.
(4) The resin composition according to (3), wherein the aliphatic polyester is poly(ε-caprolactone).
(5) The resin composition according to any one of (1) to (4), wherein the epoxy resin (C) is a bisphenol A type epoxy resin and/or a bisphenol F type epoxy resin.
( 6 ) The resin composition according to any one of (1) to ( 5 ), having a tensile elongation at break of 20% or more at a tensile speed of 5 mm/min in accordance with ISO 527 (2012).
( 7 ) A molded product obtained by molding the resin composition according to any one of (1) to ( 6 ).
( 8 ) A method for producing a resin composition according to any one of (1) to ( 6 ), comprising melt-kneading at least a polyarylene sulfide (A), a modified cyclodextrin (B), and an epoxy resin (C).

The resin composition of the present invention provides molded products with an excellent balance of rigidity and toughness.

The present invention will now be described in further detail.
The resin composition of the present invention is made by blending at least polyarylene sulfide (A), modified cyclodextrin (B), and epoxy resin (C). By blending polyarylene sulfide (A), rigidity and heat resistance can be improved. In addition, by blending modified cyclodextrin (B), toughness can be improved. In addition, by blending epoxy resin (C), the toughness improving effect of modified cyclodextrin (B) can be enhanced. In addition, the resin composition of the present invention includes a product obtained by reacting component (A) with component (B) and component (C) in addition to polyarylene sulfide (A) component, modified cyclodextrin (B) component, and epoxy resin (C) component, but it is not practical to specify the structure of the reactant. Therefore, the present invention is specified by each component to be blended.

The polyarylene sulfide (A) in the present invention is a homopolymer or copolymer having a repeating unit of the formula -(Ar-S)- as the main structural unit. Here, "main structural unit" means that the repeating unit accounts for 80 mol% or more of all structural units constituting the polyarylene sulfide. Examples of the Ar include any of the units represented by the following formulas (a) to (k), among which the unit represented by formula (a) is particularly preferred.

上記式（ａ）～式（ｉ）中、Ｒ１、Ｒ２は水素、アルキル基、アルコキシ基、ハロゲン基、カルボキシル基から選ばれた置換基であり、Ｒ１とＲ２は同一でも異なっていてもよい。※は連結部位を示す。

In the above formulas (a) to (i), R1 and R2 are substituents selected from hydrogen, an alkyl group, an alkoxy group, a halogen group, and a carboxyl group, and R1 and R2 may be the same or different. * indicates a linking site.

As long as the repeating unit -(Ar-S)- is the main constituent unit, it may contain a small amount of branching units or crosslinking units represented by the following formulas (l) to (n), etc. The content of these branching units or crosslinking units is preferably in the range of 0 to 1 mol% per 1 mol of -(Ar-S)- units.

Typical examples of these polyarylene sulfides include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ether, and polyphenylene sulfide ketone. A particularly preferred polyarylene sulfide is polyphenylene sulfide (PPS) containing 90 mol % or more of p-phenylene sulfide units shown in the following formula as the main structural unit of the polymer. m-phenylene units and o-phenylene units can also be included, but in order to maintain the high heat resistance and chemical resistance of polyarylene sulfide, a content of 10 mol % or less is preferable.

The polyarylene sulfide (A) in the present invention may be produced by any method as long as it has a polyarylene sulfide structure with the repeating unit -(Ar-S)- as the main constituent unit. Examples of such methods include a method of reacting a dichloro aromatic compound with a sulfidizing agent in an organic polar solvent, a method of heating a cyclic polyarylene sulfide to convert it to a polyarylene sulfide, and a method of melting and reacting a diiodo aromatic compound with elemental sulfur. There are also no particular limitations on the post-treatment of the polyarylene sulfide obtained by these methods. For example, the polyarylene sulfide may be washed with a solvent to remove oligomer components, reduced in solvent or gas components by heating or devolatilization, crosslinked in an oxygen atmosphere, or melted again to perform an additional reaction.

The resulting polyarylene sulfide may contain a functional group, such as an amino group, an acetamide group, a sulfonamide group, a sulfonic acid group, a carboxyl group, a hydroxyl group, a thiol group, a cyano group, an isocyanate group, an aldehyde group, an acetyl group, an acid anhydride group, an epoxy group, a silanol group, an alkoxysilane group, or a reactive functional group derived from the above functional groups. There are no particular limitations on the bonding positions of these functional groups, and they are located in the side chains and/or terminals of the polyarylene sulfide.

In the resin composition of the present invention, from the viewpoint of achieving excellent tensile elongation at break, the number average molecular weight of the polyarylene sulfide (A) used in the formulation is preferably 10,000 or more, and more preferably 13,000 or more. The upper limit of the number average molecular weight of the polyarylene sulfide (A) is not particularly limited, but from the viewpoint of moldability, it is preferably 50,000 or less. The number average molecular weight (Mn) of the polyarylene sulfide referred to here is a value calculated in terms of polystyrene using gel permeation chromatography (GPC) manufactured by Senshu Scientific Co., Ltd.

In the resin composition of the present invention, the melting point of the polyarylene sulfide (A) is preferably 150° C. or more and less than 300° C. If the melting point is 150° C. or more, the heat resistance can be improved. On the other hand, if the melting point is less than 300° C., the thermal decomposition of the modified cyclodextrin (B) can be suppressed during the production of the resin composition.
The melting point of the polyarylene sulfide in the present invention is the temperature of an endothermic peak that appears when the polyarylene sulfide is cooled from a molten state to 30° C. at a temperature drop rate of 20° C./min in an inert gas atmosphere using a differential scanning calorimeter manufactured by TA Instruments, and then heated to the melting point+40° C. at a temperature rise rate of 20° C./min. However, when two or more endothermic peaks are detected, the temperature of the endothermic peak with the greatest peak intensity is regarded as the melting point.

The amount of polyarylene sulfide (A) in the resin composition of the present invention is 80 parts by mass or more and 99.9 parts by mass or less, based on 100 parts by mass of the total of polyarylene sulfide (A), modified cyclodextrin (B), and epoxy resin (C). If the amount of polyarylene sulfide (A) is less than 80 parts by mass, the tensile strength, rigidity, and heat resistance of the resulting molded product will decrease. The amount of polyarylene sulfide (A) is preferably 90 parts by mass or more, more preferably 93 parts by mass or more. On the other hand, if the amount of polyarylene sulfide (A) exceeds 99.9 parts by mass, the amount of modified cyclodextrin (B) and epoxy resin (C) will be relatively small, and the toughness of the molded product will decrease. The amount of polyarylene sulfide (A) is preferably 99.5 parts by mass or less.

The resin composition of the present invention contains a modified cyclodextrin (B).
The modified cyclodextrin is a compound represented by the following general formula (o), in which the glucose constituting the cyclodextrin is modified with a functional group R.

上記一般式（ｏ）において、ｎは６～８の整数、Ｒは水酸基、ヒドロキシプロポキシ基、アルコキシ基、ポリアルキレングリコキシ基、脂肪族ポリエステル、ヒドロキシプロポキシ基を介したポリアルキレングリコール、ヒドロキシプロポキシ基を介した脂肪族ポリエステルから選ばれる官能基である。Ｒは同一であっても、それぞれ異なっていてもよい。但し、全てのＲが水酸基の場合を除く。

In the above general formula (o), n is an integer of 6 to 8, and R is a functional group selected from a hydroxyl group, a hydroxypropoxy group, an alkoxy group, a polyalkyleneglycoxy group, an aliphatic polyester, a polyalkylene glycol via a hydroxypropoxy group, and an aliphatic polyester via a hydroxypropoxy group. R may be the same or different, except for the case where all R are hydroxyl groups.

Modified cyclodextrin (B) is obtained by chemically modifying and converting the hydroxyl groups of glucose, which is the basic structure that constitutes cyclodextrin. Examples of cyclodextrins that can be used as raw materials for modified cyclodextrin (B) include α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin. Of these, β-cyclodextrin and γ-cyclodextrin are more preferably used. By using modified cyclodextrin (B) obtained by modifying these preferred cyclodextrins, the toughness of the molded products obtained in the resin composition of the present invention is improved.

Specific examples of modifying groups that chemically modify or convert the hydroxyl groups of cyclodextrin include modified cyclodextrins in which the hydroxyl groups of cyclodextrin are modified with alkoxy groups such as methoxy groups, ethoxy groups, and propoxy groups, or hydroxypropoxy groups, modified cyclodextrins in which polyalkylene glycol or aliphatic polyesters are directly bonded to cyclodextrin, and modified cyclodextrins in which polyalkylene glycol or aliphatic polyesters are bonded to cyclodextrin via a linking group. Examples of aliphatic polyesters include polylactic acid, polyglycolic acid, poly 3-hydroxybutyrate, poly 4-hydroxybutyrate, poly (3-hydroxybutyrate/3-hydroxyvalerate), and poly (ε-caprolactone). Two or more of these may be combined. Among these, from the viewpoint of toughness expression in the resulting molded article, those modified with hydroxypropoxy groups or methoxy groups, or those modified with hydroxypropoxy groups and poly(ε-caprolactone) are preferred, and cyclodextrin modified with hydroxypropoxy groups and poly(ε-caprolactone) is particularly preferred.

In the case where the modified cyclodextrin (B) in the resin composition of the present invention is modified with poly(ε-caprolactone), the molecular weight of the PCL chain is preferably equal to or greater than the molecular weight of the epoxy resin (C) used. In the present invention, the "molecular weight of the PCL chain" is defined as the value obtained by multiplying the integral value of the peak corresponding to the proton at the γ position of PCL observed near 1.38 ppm, when the residual proton peak of deuterated chloroform is taken as the reference (7.26 ppm) when the proton nuclear magnetic resonance of a 1% by mass solution of the modified cyclodextrin (B) is measured using a nuclear magnetic resonance apparatus, by the integral value of the peak corresponding to the proton of the methylene group adjacent to the hydroxyl group at the end of the PCL chain observed near 3.65 ppm, multiplied by the molar mass of the repeating unit of PCL, 114.14 g/mol. In addition, in the present invention, "equivalent to the molecular weight of the epoxy resin (C)" means that the molecular weight of the PCL chain is equal to or greater than the molecular weight of the epoxy resin ±300 g/mol. When the molecular weight of the PCL chain is equal to or greater than the molecular weight of the epoxy resin, the effect of the epoxy resin (C) in stabilizing the interface between the modified cyclodextrin (B) and the polyarylene sulfide (A) is fully exerted, and the toughness improving effect can be enhanced.

The thermal decomposition temperature of the modified cyclodextrin (B) in the resin composition of the present invention is preferably 300°C or higher. When the modified cyclodextrin (B) has a 5% mass reduction temperature measured by thermogravimetric analysis of 300°C or higher, thermal decomposition during the production and molding of the resin composition is suppressed, and a stress relaxation effect can be achieved. The "5% mass reduction temperature measured by thermogravimetric analysis" in the present invention is defined as the temperature at which the mass of the modified cyclodextrin (B) is reduced by 5% relative to the mass before heating when the modified cyclodextrin (B) is heated from 40°C to 350°C at a rate of 10°C/min under an inert gas atmosphere using a thermogravimeter. An example of a method for controlling the 5% mass reduction temperature of the modified cyclodextrin (B) measured by thermogravimetric analysis to the above range is the addition of an acid. The polymerization catalyst used in preparing the modified cyclodextrin can be inactivated by adding an acid. The acid may be either an organic acid or an inorganic acid, but preferably an inorganic acid such as hydrochloric acid, sulfuric acid, or phosphoric acid, and more preferably phosphoric acid. By using these preferred acids, the polymerization catalyst is inactivated and the transesterification reaction caused by the polymerization catalyst is suppressed, thereby improving the thermal stability of the modified cyclodextrin (B). Examples of methods for adding an acid include a method of adding and mixing the acid directly to the modified cyclodextrin (B), a method of adding and mixing the acid to a solution in which the modified cyclodextrin (B) is dissolved, and a method of impregnating the modified cyclodextrin (B) in an acidic liquid. From the viewpoint of processability, it is particularly preferable to add the acid directly to the modified cyclodextrin after synthesis and stir the acid. These acids may be used as they are, or may be used as a solution diluted in a solvent.

The amount of modified cyclodextrin (B) in the resin composition of the present invention is preferably 0.1 parts by mass or more and 20 parts by mass or less, more preferably 0.5 parts by mass or more, based on 100 parts by mass of the polyarylene sulfide (A), the modified cyclodextrin (B), and the epoxy resin (C) in total. The total amount of modified cyclodextrin (B) and epoxy resin (C) is preferably 0.1 parts by mass or more and 19.9 parts by mass or less, more preferably 0.5 parts by mass or more, based on 100 parts by mass of the polyarylene sulfide (A), the modified cyclodextrin (B), and the epoxy resin (C) in total. When the total amount of modified cyclodextrin (B) and epoxy resin (C) is 0.1 parts by mass or more, the stress relaxation effect of modified cyclodextrin (B) is sufficiently exhibited, and the toughness of the molded product is improved. On the other hand, by setting the total amount of modified cyclodextrin (B) and epoxy resin (C) to 19.9 parts by mass or less, the amount of polyarylene sulfide (A) is relatively large, and the rigidity and heat resistance of the resulting molded article are improved. The amount of modified cyclodextrin (B) alone is preferably 0.05 parts by mass or more and 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of the total of polyarylene sulfide (A), modified cyclodextrin (B), and epoxy resin (C). By setting the amount of modified cyclodextrin (B) in these preferred ranges, a resin composition and molded article having an excellent balance between rigidity and toughness can be obtained.

The resin composition of the present invention contains an epoxy resin (C).
Examples of the epoxy resin (C) include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, halogenated bisphenol A type epoxy resin, bisphenol S type epoxy resin, resorcinol type epoxy resin, hydrogenated bisphenol A type epoxy resin, aliphatic epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, etc. Among these epoxy resins, bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferred because they have an excellent balance between viscosity and heat resistance and have excellent affinity with the modified cyclodextrin (B).

The number average molecular weight of the epoxy resin (C) is preferably 500 to 100,000. More preferably, it is 1,000 to 80,000, and even more preferably, it is 1,500 to 5,000. A number average molecular weight of 500 or more results in excellent heat resistance, and a number average molecular weight of 100,000 or less results in excellent reactivity with the polyarylene sulfide (A). The number average molecular weight of the epoxy resin (C) can be measured using gel permeation chromatography (GPC).

The amount of epoxy resin (C) in the resin composition of the present invention is preferably 0.1 parts by mass or more and 19.9 parts by mass or less, and more preferably 0.5 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the total of polyarylene sulfide (A), modified cyclodextrin (B), and epoxy resin (C). By having the amount of epoxy resin (C) in this preferred range, it is possible to efficiently transmit the stress relaxation effect of the modified cyclodextrin (B) to the polyarylene sulfide (A), and it is possible to obtain a resin composition and a molded product having an excellent balance between rigidity and toughness.

The resin composition of the present invention has a sea-island structure, in which the sea phase is made up of 80% by mass or more of polyarylene sulfide (A), and the island phase is made up of 80% by mass or more of the modified cyclodextrin (B) and the epoxy resin (C). The average diameter of the island phase is 1 μm or less. In order to stabilize the interface between the modified cyclodextrin (B) and the polyarylene sulfide (A), the amount of the epoxy compound (C) contained in the island phase in which the modified cyclodextrin (B) and the epoxy resin (C) account for 80% by mass or more in total is preferably 25 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 100 parts by mass or more, per 100 parts by mass of the modified cyclodextrin (B). It is known that the properties of the resin composition are also affected by the phase separation structure and the size of the phase. A resin composition consisting of two or more components and having a phase separation structure brings out the advantages of each component and complements the disadvantages of each component, thereby exhibiting superior properties compared to the case of each component alone. In the sea-island structure of the resin composition of the present invention, the average diameter of the island phase is preferably 0.01 μm or more, more preferably 0.02 μm or more. When the average diameter of the island phase is 0.01 μm or more, the characteristics derived from the phase separation structure are more effectively exhibited, and the toughness can be improved without impairing the excellent heat resistance of the polyarylene sulfide. In addition, the average diameter of the island phase is 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.2 μm or less. When the average diameter of the island phase is 1 μm or less, the number of island phases is sufficiently increased, and the stress relaxation effect of the modified cyclodextrin (B) can be exhibited throughout the resin.

The average diameter of the island phases in the sea-island structure in the resin composition of the present invention can be obtained by the following method through electron microscope observation. Since the phase separation structure and the size of each phase of the resin composition do not change under general molding conditions, in the present invention, the phase separation structure is observed using a test piece obtained by molding the resin composition. First, the center of the cross-sectional direction of an ISO527-2-5A dumbbell test piece obtained by injection molding is cut into 1 to 2 mm squares, and ultra-thin slices of 0.1 μm or less (about 80 nm) are cut at room temperature using an ultramicrotome to obtain a sample for transmission electron microscope. When the average diameter of the island phases in the sea-island structure is obtained, the magnification of the above-mentioned sample for transmission electron microscope is adjusted so that 50 or more island phases are present in a square electron microscope observation photograph. At such magnification, 50 island phases are randomly selected from the island phases present in the observation image, and the long axis and short axis of each island phase are measured. The average value of the long axis and short axis is taken as the diameter of each island phase, and the average value of the diameters of all the measured island phases is taken as the average diameter of the island phases. The long diameter and short diameter of the island phase refer to the longest diameter and the shortest diameter of each island phase.
The sea-island structure in which the average diameter of the island phases is in the above-mentioned preferred range can be obtained, for example, by adjusting the blending amounts of the polyarylene sulfide (A), the modified cyclodextrin (B), and the epoxy resin (C) to be within the above-mentioned preferred ranges. The average diameter of the island phases tends to be smaller as the blending amount of the modified cyclodextrin (B) is smaller, and the average diameter of the island phases tends to be larger as the blending amount of the modified cyclodextrin (B) is larger.
In addition, a sea-island structure in which the average diameter of the island phases falls within the above-mentioned preferred range can also be obtained by adjusting the molecular weight of the epoxy resin (C) to fall within the above-mentioned preferred range. The smaller the molecular weight of the epoxy resin (C), the smaller the average diameter of the island phases tends to be, whereas the higher the molecular weight of the epoxy resin (C), the larger the average diameter of the island phases tends to be.

The resin composition of the present invention contains polyarylene sulfide (A), modified cyclodextrin (B), and epoxy resin (C), and has a tensile breaking elongation of 20% or more at a tensile speed of 5 mm/min according to ISO 527 (2012). A tensile breaking elongation of 20% or more makes it possible to obtain a molded product with excellent rigidity and toughness. The tensile breaking elongation is preferably 40% or more, and particularly preferably 100% or more.

The resin composition of the present invention may contain an inorganic filler as long as the effect of the present invention is not impaired. Specific examples of such inorganic fillers include fibrous fillers such as glass fibers, carbon fibers, carbon nanotubes, carbon nanohorns, potassium titanate whiskers, zinc oxide whiskers, calcium carbonate whiskers, wollastonite whiskers, aluminum borate whiskers, aramid fibers, alumina fibers, silicon carbide fibers, ceramic fibers, asbestos fibers, gypsum fibers, and metal fibers, or fullerenes, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, asbestos, alumina, and the like. Examples of inorganic fillers include silicates such as silicates, metal compounds such as silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide, and iron oxide, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, sulfates such as calcium sulfate and barium sulfate, hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide, glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, and non-fibrous fillers such as silica and graphite, and among these, glass fiber, silica, and calcium carbonate are preferred. These inorganic fillers may be hollow, and two or more types may be used in combination. These inorganic fillers may also be pretreated with coupling agents such as isocyanate compounds, organic silane compounds, organic titanate compounds, organic borane compounds, and epoxy compounds before use.

The resin composition of the present invention may also contain an alkoxysilane compound. As the alkoxysilane compound, an alkoxysilane compound having at least one functional group selected from an epoxy group, an amino group, an isocyanate group, a hydroxyl group, a mercapto group, and a ureido group may be used. The amount added is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 3 parts by mass. Specific examples of such compounds include epoxy group-containing alkoxysilane compounds such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; mercapto group-containing alkoxysilane compounds such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; ureido group-containing alkoxysilane compounds such as γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, and γ-(2-ureidoethyl)aminopropyltrimethoxysilane; γ-isocyanatopropyltriethoxysilane and γ-isocyanatopropyltrimethoxysilane. , isocyanato group-containing alkoxysilane compounds such as γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanatopropylethyldiethoxysilane, and γ-isocyanatopropyltrichlorosilane; amino group-containing alkoxysilane compounds such as γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane; and hydroxyl group-containing alkoxysilane compounds such as γ-hydroxypropyltrimethoxysilane and γ-hydroxypropyltriethoxysilane.

Furthermore, resins other than polyphenylene sulfide may be added to the resin composition of the present invention. Specific examples include polyamide resins, polybutylene terephthalate resins, polyethylene terephthalate resins, modified polyphenylene ether resins, polysulfone resins, polyarylsulfone resins, polyketone resins, polyarylate resins, liquid crystal polymers, polyether ketone resins, polythioether ketone resins, polyether ether ketone resins, polyimide resins, polyetherimide resins, polyethersulfone resins, polyamideimide resins, and tetrafluoroethylene resins.

In addition, for the purpose of modification, it is possible to include the following compounds. Plasticizers such as polyalkylene oxide oligomer compounds, thioether compounds, ester compounds, and organic phosphorus compounds, crystal nucleating agents such as organic phosphorus compounds and polyether ether ketone, montan acid waxes, metal soaps such as lithium stearate and aluminum stearate, release agents such as ethylenediamine-stearic acid-sebacic acid polycondensates and silicone compounds, color inhibitors such as hypophosphites, phenolic antioxidants such as (3,9-bis[2-(3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane), phosphorus antioxidants such as bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, and other conventional additives such as water, lubricants, ultraviolet inhibitors, colorants, and foaming agents. The above compound is preferably 10 parts by mass or less, and more preferably 1 part by mass or less, per 100 parts by mass of polyarylene sulfide (A).

The resin composition of the present invention is produced by melt-kneading at least polyarylene sulfide (A), modified cyclodextrin (B), and epoxy resin (C). Examples of melt-kneading devices include extruders such as single-screw extruders, twin-screw extruders, and multi-screw extruders such as four-screw extruders, and twin-screw composite extruders, and kneaders. From the viewpoint of productivity, an extruder capable of continuous production is preferred, and from the viewpoints of improving kneading properties and productivity, a twin-screw extruder is more preferred.

The following describes an example of producing the resin composition of the present invention using a twin-screw extruder. From the viewpoint of suppressing thermal degradation of the modified cyclodextrin (B) and further improving toughness, the maximum resin temperature during melt kneading is preferably 350°C or lower. On the other hand, the maximum resin temperature is preferably equal to or higher than the melting point of the polyarylene sulfide (A). Here, the maximum resin temperature refers to the highest temperature measured using resin thermometers evenly installed at multiple positions on the extruder.

The resin composition obtained in this manner can be molded by various molding techniques, such as injection molding, extrusion molding, compression molding, blow molding, and injection compression molding, but is particularly useful for injection molding and extrusion molding.

Applications of molded products obtained by injection molding include electrical equipment parts such as generators, electric motors, transformers, current transformers, voltage regulators, rectifiers, inverters, relays, power contacts, switches, circuit breakers, knife switches, multi-pole rods, and electrical component cabinets; sensors, LED lamps, connectors, sockets, resistors, relay cases, small switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, semiconductors, liquid crystal displays, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, and con Electronic components such as pewter-related components; VTR components, television components, irons, hair dryers, rice cooker components, microwave oven components, audio components, compact discs and other audio equipment components; lighting components, refrigerator components, air conditioner components, typewriter components, word processor components and other home and office electrical appliance components; office computer components, telephone components, facsimile components, copier components, cleaning tools, motor components, lighters, typewriters and other machine components; microscopes, binoculars, cameras, clocks and other optical and precision machinery components; alternator terminals, alternator connectors, IC regulators, light dimmer pots various valves such as sensitometer bases, exhaust gas valves, and air conditioner refrigerant adjustment valves; various pipes and ducts for fuel, exhaust systems, and intake systems, turbo ducts, air intake nozzle snorkels, intake manifolds, fuel pumps, engine coolant joints, carburetor main bodies, carburetor spacers, exhaust gas sensors, coolant sensors, oil temperature sensors, brake pad wear sensors, throttle position sensors, crankshaft position sensors, air flow meters, brake pad wear sensors, thermostat bases for air conditioners, heating hot air flow control valves, brush holders for radiator motors, water pump impellers, Examples include automobile and vehicle-related parts such as turbine vanes, wiper motor-related parts, distributors, starter switches, starter relays, transmission wire harnesses and cable ties, windshield washer nozzles, air conditioner panel switch boards, coils for fuel-related electromagnetic valves, fuse connectors, horn terminals, electrical component insulation plates, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, and ignition device cases; gaskets for primary or secondary batteries in mobile phones, notebook computers, video cameras, hybrid cars, electric cars, etc.; and more.

Examples of molded products obtained by extrusion molding include round bars, square bars, sheets, films, tubes, and pipes. More specific uses include electrical insulating materials for water heater motors, air conditioner motors, and drive motors, film capacitors, speaker diaphragms, magnetic tape for recording, printed circuit board materials, peripheral parts for printed circuit boards, semiconductor packages, semiconductor transport trays, process and release films, protective films, automotive film sensors, insulating tape for wire cables, insulating washers in lithium-ion batteries, tubes for hot water, coolant, and chemicals, automotive fuel tubes, automotive turbo ducts, hot water piping, chemical piping in chemical plants, piping for ultrapure water and ultra-high purity solvents, automotive piping, piping pipes for fluorocarbons and supercritical carbon dioxide refrigerants, and workpiece retaining rings for polishing equipment. Other examples include coated molded articles for windings of motor coils in hybrid and electric vehicles, railways, and power generation equipment; heat-resistant electric cables for home appliances; wire harnesses and control wires such as flat cables used for wiring inside automobiles; and coated molded articles for windings of signal transformers or on-board transformers for communication, transmission, high frequency, audio, measurement, etc.

The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The following raw materials were used to obtain the resin compositions of the examples and comparative examples.
<Polyarylene sulfide>
(A-1): Polyphenylene sulfide resin was produced by the method of Reference Example 1. The number average molecular weight was 13,700 and the melting point was 288°C.

<Modified Cyclodextrin>
(B-1): This was prepared by modifying hydroxypropylated β-cyclodextrin (Sigma-Aldrich) with polycaprolactone and recovering it by the method of Reference Example 2. The 5% mass loss temperature was 339.5° C., and the molecular weight of the PCL chain was 3,562.
(B-2): This was prepared by modifying hydroxypropylated β-cyclodextrin (Sigma-Aldrich) with polycaprolactone and recovering it by the method of Reference Example 3. The 5% mass loss temperature was 336.2° C., and the molecular weight of the PCL chain was 2,465.

<Epoxy resin>
(C-1): Bisphenol A type epoxy resin jER1007 (number average molecular weight: 2,900) manufactured by Mitsubishi Chemical Corporation was used after being vacuum dried at 160° C. for 12 hours.
(C-2): Bisphenol A type epoxy resin jER1004AF (number average molecular weight: 1,650) manufactured by Mitsubishi Chemical Corporation was used after being vacuum dried at 160° C. for 12 hours.
(C-3): bisphenol A type epoxy resin jER1010 (number average molecular weight: 5,500) manufactured by Mitsubishi Chemical Corporation was used after being vacuum dried at 160° C. for 12 hours.
(C-4): Bisphenol A type epoxy resin jER1256 (weight average molecular weight: 50,000) manufactured by Mitsubishi Chemical Corporation was used after being vacuum dried at 160° C. for 12 hours.

(Reference Example 1)
In a 70-liter autoclave equipped with a stirrer and a bottom plug valve, 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.94 kg (70.63 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 1.89 kg (23.1 mol) of sodium acetate, and 5.50 kg of ion-exchanged water were charged, and the mixture was gradually heated to 245° C. over about 3 hours while passing nitrogen through it at normal pressure. After distilling out 9.77 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200° C. The amount of water remaining in the system per mole of the charged amount of alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mole of the charged amount of alkali metal sulfide.

After cooling the reaction vessel to 200°C, 10.42 kg (70.86 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the temperature was raised from 200°C to 270°C at a rate of 0.6°C/min while stirring at 240 rpm, and the reaction was carried out at 270°C for 140 minutes. Thereafter, 2.40 kg (133 mol) of water was injected while cooling from 270°C to 250°C over 15 minutes. Then, the mixture was gradually cooled from 250°C to 220°C over 75 minutes, and then quenched to near room temperature, and the contents were removed.
The contents were diluted with about 35 liters of NMP, stirred at 85°C for 30 minutes as a slurry, and filtered through an 80 mesh wire net (opening 0.175 mm) to obtain a solid. The obtained solid was washed and filtered with about 35 liters of NMP in the same manner. The obtained solid was added to 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and then filtered through an 80 mesh wire net to recover the solid. This operation was repeated three times in total. The obtained solid and 32 g of acetic acid were added to 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and then filtered through an 80 mesh wire net. The obtained solid was further added to 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and then filtered through an 80 mesh wire net to recover the solid. The solid thus obtained was dried at 120°C under a nitrogen stream to obtain a dried polyphenylene sulfide resin (A-1).

(Reference Example 2)
2.0 g of hydroxypropylated β-cyclodextrin was dissolved in 91.2 g of ε-caprolactone under nitrogen flow by gradually increasing the temperature from 110°C to 130°C and then to 150°C in an oil bath while stirring for 30 minutes at each temperature. After cooling the oil bath to 130°C, a catalyst solution prepared by diluting 0.5 g of tin(II) octylate with 1.6 g of toluene was added dropwise to the mixed solution and stirred at 130°C for 4 hours. 1.2 g of a 10% by mass phosphoric acid solution in tetrahydrofuran was added to the resulting reaction product and stirred at 130°C for 20 minutes, and then the product was recovered without purification and vacuum dried at 80°C for 12 hours to obtain modified cyclodextrin (B-1).

(Reference Example 3)
0.64 g of hydroxypropylated β-cyclodextrin was dissolved in 41.5 g of ε-caprolactone under nitrogen flow by gradually increasing the temperature from 110°C to 130°C and then to 150°C in an oil bath while stirring for 30 minutes at each temperature. After cooling the oil bath to 130°C, a catalyst solution prepared by diluting 0.25 g of tin(II) octoate with 0.8 g of toluene was dropped into the mixed solution and stirred at 130°C for 4 hours. 0.6 g of a 10% by mass phosphoric acid tetrahydrofuran solution was added to the resulting reaction product and stirred at 130°C for 20 minutes, and then the product was recovered without purification and vacuum dried at 80°C for 12 hours to obtain modified cyclodextrin (B-2).

<Evaluation method>
The evaluation methods used in each of the examples and comparative examples will be described below.
(1) Number Average Molecular Weight The number average molecular weight (Mn) of the polyphenylene sulfide resin was calculated in terms of polystyrene using gel permeation chromatography (GPC) manufactured by Senshu Scientific Co., Ltd. under the conditions shown below.
Equipment: SSC-7100 (Senshu Science)
Column name: GPC3506 (Senshu Kagaku)
Eluent: 1-chloronaphthalene Detector: Differential refractive index detector Column temperature: 210°C
Pre-thermostat temperature: 250°C
Pump thermostatic chamber temperature: 50°C
Detector temperature: 210°C
Flow rate: 1.0mL/min
Sample injection volume: 300 μL (slurry: approximately 0.2% by mass)

(2) Melting Point The polyphenylene sulfide resin (A-1) obtained in Reference Example 1 was cooled from a molten state to 30° C. at a temperature drop rate of 20° C./min under an inert gas atmosphere, and then heated to the melting point+40° C. at a temperature increase rate of 20° C./min, to determine the melting point using a differential scanning calorimeter (DSC-Q20 manufactured by TA Instruments).

(3) Thermal decomposition temperature (5% mass loss temperature)
The modified cyclodextrins (B-1) and (B-2) obtained in Reference Examples 2 and 3 were subjected to a thermogravimetry test under a nitrogen flow at a temperature increased from 40° C. using a thermogravimeter (TG/DTA7200 manufactured by Hitachi High-Tech Science). The 5% mass loss temperature was determined by measuring the mass change at a rate of 10° C./min.

(4) Molecular Weight of PCL Chain The modified cyclodextrins (B-1) and (B-2) obtained in Reference Examples 2 and 3 were dissolved in deuterated chloroform to a concentration of 1% by mass, and proton nuclear magnetic resonance spectra were obtained using a nuclear magnetic resonance apparatus (JNM-ECZ500R manufactured by JEOL Ltd.).

(5) Rigidity, toughness (tensile strength, tensile elongation at break)
The components were mixed in the ratios shown in Table 1, preblended, and melt-kneaded in a small kneader (MiniLab manufactured by HAAKE) set at a cylinder temperature of 320° C. The extruded gut was pelletized to obtain pellets, and the pellets were injection molded in an injection molding machine (Minijet manufactured by HAAKE) set at a cylinder temperature of 320° C. and a mold temperature of 130° C. to prepare a dumbbell-shaped test piece conforming to ISO527-2-5A. The test piece was subjected to a tensile test at a tensile speed of 5 mm/min using a tensile tester Autograph AG-20kNX (manufactured by Shimadzu Corporation) in accordance with ISO527 (2012), and the maximum stress and tensile elongation at break were determined.

(6) Morphology of phase-separated structure and diameter of island phase The center of the cross-sectional direction of a dumbbell-shaped test piece conforming to ISO527-2-5A, which was injection molded under the above conditions, was cut into 1 to 2 mm squares, and then ultra-thin slices of 0.1 μm or less (about 80 nm) were cut at room temperature using an ultramicrotome (EM UC7 manufactured by Leica) to prepare samples for transmission electron microscopy. The phase structure of the cross section of the observation sample was observed using a transmission electron microscope (Hitachi H-7100 manufactured by Hitachi Ltd.) at an acceleration voltage of 100 kV to confirm the morphology of the phase-separated structure. A sea phase mainly composed of polyphenylene sulfide and a phase mainly composed of modified cyclodextrin and epoxy resin formed in particulate form were present, and a structure in which particles were scattered in this sea phase was defined as a sea-island structure.
The diameter of each island phase was determined for each sample having the sea-island structure by the following method. The magnification was adjusted appropriately so that 50 or more island phases were present in a square electron microscope photograph. At this magnification, 50 island phases were randomly selected from the island phases present in the observation image, and the long and short diameters of each island phase were measured. The average of the long and short diameters was taken as the diameter of each island phase, and the average of the diameters of all the measured island phases was taken as the average diameter of the island phases. The long and short diameters of the island phases refer to the longest and shortest diameters of each island phase.

(Examples 1 to 6, Comparative Examples 1 to 3)
The raw materials shown in Table 1 were used and the evaluation results according to the above method are shown in Table 1.

As shown in the comparative examples in Table 1 above, polyarylene sulfide has excellent tensile strength, but has problems with tensile elongation at break. Comparing Examples 1 to 6 with Comparative Example 1, it was found that the resin composition consisting of polyarylene sulfide, modified cyclodextrin, and epoxy resin has a sea-island structure with an average diameter of the island phase of 1 μm or less, and has superior toughness compared to polyarylene sulfide alone. On the other hand, in Comparative Example 2, even if modified cyclodextrin is added to the polyarylene sulfide, the effect of improving toughness was limited. In addition, Comparative Examples 1 and 3 also showed that the resin composition consisting of polyarylene sulfide and epoxy resin has inferior toughness compared to polyarylene sulfide alone.

Claims (8)

The resin composition is obtained by blending at least a polyarylene sulfide (A), a modified cyclodextrin (B), and an epoxy resin (C), and the resin composition is obtained by blending 80 parts by mass or more and 99.9 parts by mass or less of the polyarylene sulfide (A) and 0.1 parts by mass or more and 20 parts by mass or less of the modified cyclodextrin (B) and the epoxy resin (C) in total, relative to 100 parts by mass of the polyarylene sulfide (A), the modified cyclodextrin (B), and the epoxy resin (C) . The resin composition is a mixture of at least polyarylene sulfide (A), modified cyclodextrin (B), and epoxy resin (C), and has a sea-island structure consisting of a sea phase mainly composed of the polyarylene sulfide ( A ) and an island phase mainly composed of the modified cyclodextrin (B) and the epoxy resin (C), and the average diameter of the island phase is 1 μm or less. The resin composition according to claim 1 or 2, characterized in that the modified cyclodextrin (B) is modified with an aliphatic polyester. The resin composition according to claim 3, characterized in that the aliphatic polyester is poly(ε-caprolactone). The resin composition according to any one of claims 1 to 4, characterized in that the epoxy resin (C) is a bisphenol A type epoxy resin and/or a bisphenol F type epoxy resin. The resin composition according to any one of claims 1 to 5, having a tensile elongation at break of 20% or more at a tensile speed of 5 mm/min according to ISO 527 (2012). A molded article obtained by molding the resin composition according to any one of claims 1 to 6 . 7. The method for producing a resin composition according to claim 1, wherein at least the polyarylene sulfide (A), the modified cyclodextrin (B), and the epoxy resin (C) are melt-kneaded.