Resin composition, method for producing resin composition, and method for producing sintered body

Abstract

Provided is a resin composition containing an aliphatic polycarbonate having a polydiversity index (PDI), represented by the mass-average molecular weight (Mw) / the number-average molecular weight (Mn), of 14 or more.

Description

Resin composition, method for manufacturing the resin composition, and method for manufacturing a sintered body

[0001] The present invention relates to a resin composition, a method for producing a resin composition, and a method for producing a sintered body.

[0002] Conventionally, in the fields of electronic materials, structural materials, etc., a method has been used to form ceramics, sintered metals, etc., by mixing sintering particles and a firing binder to create a firing material, shaping it into a desired form, and then firing it.

[0003] For example, Patent Document 1 describes an aluminum nitride green sheet comprising aluminum nitride powder, a sintering aid, a thermoplastic resin, and a plasticizer, wherein the thermoplastic resin is polyvinyl butyral resin, and the plasticizer has a molecular weight of 300 or more and is an ester of an aliphatic polycarboxylic acid and an aliphatic monoalcohol or an ester of an aliphatic polycarboxylic acid and an aliphatic monocarboxylic acid, and has two or more ester bonds.

[0004] Japanese Patent Publication No. 2019-178042

[0005] When forming a film from a sintering material, which is a mixture of sintering particles and a sintering binder, a paste-like resin composition is prepared by dispersing the sintering particles in a solution in which the sintering binder is dissolved. This paste-like resin composition is then applied to a support sheet and dried. However, if the thixotropy of the paste-like resin composition is high, or if the sintering particles tend to settle, it may not be possible to form a film of the desired shape. Furthermore, if the film formed by the above method does not have sufficient flexibility, cracks may occur in the film when it is handled. As a method to increase the flexibility of the film, a method using a plasticizer, as described in Patent Document 1, is employed. However, because plasticizers have high boiling points, this method results in a time-consuming degreasing process to remove organic components by heating, leading to a decrease in productivity. Moreover, resin compositions containing a sintering binder need to be sintered at a relatively high temperature in order to sufficiently thermally decompose the sintering binder during sintering. From the viewpoint of productivity, it is desirable to be able to sinter at the lowest possible temperature.

[0006] This invention has been made in view of the above circumstances, and aims to provide a resin composition that is excellent in coating suitability and flexibility in film form and can be fired at low temperatures, a method for manufacturing the resin composition, and a method for manufacturing a sintered body using the resin composition.

[0007] As a result of diligent research, the inventors discovered that the above problems can be solved by using a specific aliphatic polycarbonate, and thus completed the present invention described below.

[0008] In other words, the present invention relates to the following [1] to

[11] . [1] A resin composition containing an aliphatic polycarbonate having a molecular weight dispersion (PDI) of 14 or more, expressed as mass average molecular weight (Mw) / number average molecular weight (Mn). [2] The resin composition according to [1], wherein the aliphatic polycarbonate has substituted or unsubstituted aliphatic hydrocarbon groups having 2 to 6 carbon atoms in its side chains, either directly or via oxygen atoms. [3] The resin composition according to [1] or [2], wherein the aliphatic polycarbonate is polybutylene carbonate. [4] The resin composition according to any one of [1] to [3], wherein the mass average molecular weight (Mw) of the aliphatic polycarbonate is 200,000 or more. [5] The resin composition according to any one of [1] to [4], further containing one or more sintering particles selected from the group consisting of metal oxide precursor particles and metal oxide particles. [6] A resin composition according to any one of [1] to [5] above, wherein it does not contain organic acid esters, or if it contains organic acid esters, the content of organic acid esters is 10% by mass or less with respect to the total mass (100% by mass) of all components other than the solvent of the resin composition. [7] A resin composition according to [5] above, which is in the form of a paste. [8] A resin composition according to [5] above, which is in the form of a film. [9] A method for producing a resin composition according to any one of [1] to [8] above, comprising the step of polymerizing alkylene oxide and carbon dioxide in the presence of a chain transfer agent to produce an aliphatic polycarbonate.

[10] A method for producing a sintered body, wherein the resin composition according to [5] above is heated.

[11] A method for producing a sintered body according to

[10] above, wherein the resin composition is heated in an atmosphere with an oxygen partial pressure of 5.0 kPa or less.

[0009] According to the present invention, it is possible to provide a resin composition that is excellent in coating suitability and flexibility in film form and can be fired at low temperatures, a method for producing the resin composition, and a method for producing a sintered body using the resin composition.

[0010] In this specification, the lower and upper limits described in steps for a preferred numerical range can be combined independently. For example, from the description "preferably 10 to 90, more preferably 30 to 60," the "preferred lower limit (10)" and the "more preferred upper limit (60)" can be combined to arrive at "10 to 60."

[0011] In this specification, the "thickness" of an object refers to the total thickness of the object. For example, if the object consists of multiple layers, it refers to the total thickness of all the layers constituting the object. Unless otherwise specified, the "thickness" of an object in this specification refers to the average value of the thickness measured at five randomly selected locations on the object, and can be obtained using a constant-pressure thickness measuring instrument in accordance with JIS K 7130:1999.

[0012] In this specification, "solids" refers to the components of the composition in question, excluding the solvent.

[0013] In this specification, "paste" means a mixture in which some or all of the solid components are dispersed in a solvent.

[0014] The mechanism of action described herein is speculative and does not limit the mechanism by which the present invention achieves its effects.

[0015] [Resin Composition] The resin composition of this embodiment is a resin composition containing an aliphatic polycarbonate whose molecular weight dispersion (PDI), expressed as mass average molecular weight (Mw) / number average molecular weight (Mn), is 14 or more.

[0016] In the following description, the aliphatic polycarbonate contained in the resin composition of this embodiment may be referred to as "aliphatic polycarbonate (A)".

[0017] The resin composition of this embodiment exhibits excellent coating suitability and flexibility in film form, and can be fired at low temperatures. The detailed reasons for this are unknown, but the following can be inferred. The aliphatic polycarbonate (A) contained in the resin composition of this embodiment has a carbonate structure, which causes it to exhibit excellent thermal decomposition properties through a specific reaction, specifically a backbiting reaction. Therefore, the resin composition of this embodiment can be fired at relatively low temperatures. The aliphatic polycarbonate (A) contained in the resin composition of this embodiment has a molecular weight dispersion (PDI) (hereinafter also simply referred to as "PDI") of 14 or higher. The aliphatic polycarbonate (A) having a PDI within this range contains a good balance of low molecular weight material that contributes to solubility in solvents and high molecular weight material that imparts good viscosity when in solution and contributes to improved thixotropy and sedimentation resistance. Therefore, it is inferred that the resin composition of this embodiment has excellent coating suitability. Furthermore, it is presumed that the resin composition of this embodiment exhibits excellent flexibility in film form, due to the fact that the aliphatic polycarbonate (A) contained in the resin composition of this embodiment has good flexibility as a polymer alone, and that the homogeneity of the film formed due to the excellent coating properties described above is good.

[0018] <Aliphatic Polycarbonate (A)> The resin composition of this embodiment contains aliphatic polycarbonate (A). Aliphatic polycarbonate (A) may be used alone or in combination of two or more types.

[0019] (PDI of Aliphatic Polycarbonate (A)) The PDI of aliphatic polycarbonate (A) is 14 or higher. By having a PDI of aliphatic polycarbonate (A) of 14 or higher, the resin composition of this embodiment has excellent coating suitability and flexibility in film form, and can be fired at low temperatures. From the above viewpoint, the PDI of aliphatic polycarbonate (A) is preferably 15 or higher, more preferably 17 or higher, even more preferably 20 or higher, even more preferably 23 or higher, and particularly preferably 25 or higher. In addition, the PDI of aliphatic polycarbonate (A) may be 40 or less, 35 or less, or 30 or less. In this embodiment, the mass-average molecular weight (Mw) and number-average molecular weight (Mn) used to calculate the PDI of aliphatic polycarbonate (A) refer to values ​​on a standard polystyrene basis measured by gel permeation chromatography (GPC), and can be measured by the method described in the examples.

[0020] (Mass-average molecular weight (Mw) of aliphatic polycarbonate (A)) The mass-average molecular weight (Mw) of aliphatic polycarbonate (A) is preferably 200,000 or more, more preferably 250,000 or more, even more preferably 300,000 or more, and even more preferably 350,000 or more, from the viewpoint of obtaining good tensile strength. Furthermore, the mass-average molecular weight (Mw) of aliphatic polycarbonate (A) is preferably 1,000,000 or less, more preferably 800,000 or less, even more preferably 600,000 or less, and even more preferably 400,000 or less, from the viewpoint of flexibility.

[0021] (Number average molecular weight (Mn) of aliphatic polycarbonate (A)) The number average molecular weight (Mn) of aliphatic polycarbonate (A) is preferably 5,000 or more, more preferably 8,000 or more, even more preferably 10,000 or more, and even more preferably 12,000 or more, from the viewpoint of obtaining good tensile strength. Furthermore, the number average molecular weight (Mn) of aliphatic polycarbonate (A) is preferably 40,000 or less, more preferably 30,000 or less, and even more preferably 20,000 or less, from the viewpoint of flexibility.

[0022] (Types of Aliphatic Polycarbonate (A)) Aliphatic polycarbonate (A) is not particularly limited as long as it has a polymer chain in which divalent aliphatic hydrocarbon groups and carbonate units consisting of carbonate groups (-O-C(=O)-O-) are linked.

[0023] Aliphatic polycarbonate (A) is preferably one having substituted or unsubstituted aliphatic hydrocarbon groups having 2 to 6 carbon atoms in its side chains, either directly or via oxygen atoms. In this embodiment, the side chain of aliphatic polycarbonate (A) refers to an atomic group containing carbon atoms that branch off from the carbon atom chains that are linearly connected to the adjacent carbonate groups, within a molecular chain formed by linking structural units (hereinafter also referred to as "carbonate units") consisting of a divalent aliphatic hydrocarbon group and a carbonate group (-O-C(=O)-O-). The main chain of aliphatic polycarbonate (A) refers to the molecular chain formed by linking the above carbonate units, excluding the side chains. For example, when a carbonate unit consisting of a branched divalent aliphatic hydrocarbon group and a carbonate group (-O-C(=O)-O-) is linked, the carbon chain linearly connected to the carbonate group constitutes the main chain, and the carbon chains branching off from the linearly connected carbon chain among the branched divalent aliphatic hydrocarbon groups constitute the side chains.

[0024] In the following explanation, the "substituted or unsubstituted aliphatic hydrocarbon groups having 2 to 6 carbon atoms that are directly or via an oxygen atom attached to the main chain" that aliphatic polycarbonate (A) has in its side chains may be referred to as "aliphatic hydrocarbon groups (X)".

[0025] The aliphatic hydrocarbon group (X) may be linear, branched, or cyclic, and may have both linear and cyclic structures, but it is preferable that it be linear from the viewpoint of ease of manufacture, etc.

[0026] The aliphatic hydrocarbon group (X) has 2 to 6 carbon atoms. When the aliphatic hydrocarbon group (X) has 2 or more carbon atoms, the coating suitability and flexibility in the film form tend to be better. When the aliphatic hydrocarbon group (X) has 6 or fewer carbon atoms, excellent thermal decomposition properties are obtained. From the same viewpoint as above, the aliphatic hydrocarbon group (X) is preferably 2 to 5, more preferably 2 to 4, even more preferably 2 or 3, and even more preferably 2. Note that the carbon atoms of substituents are not included in the carbon atom count of the aliphatic hydrocarbon group (X) mentioned above.

[0027] Examples of substituents that the aliphatic hydrocarbon group (X) may have include hydroxyl groups, thiol groups, cyano groups, amino groups, silyl groups, halogen atoms such as fluorine, chlorine, bromine, and iodine; alkoxy groups, alkenyloxy groups; aryl groups such as phenyl groups; heteroaryl groups containing oxygen, nitrogen, sulfur, selenium, and phosphorus atoms as heteroatoms; aryloxy groups such as phenoxy groups; heteroaryloxy groups containing oxygen, nitrogen, sulfur, selenium, and phosphorus atoms as heteroatoms; alkylsilyl groups; alkylsilyloxy groups; and so on. From the viewpoint of thermal decomposition, the number of carbon atoms in the substituents that the aliphatic hydrocarbon group (X) may have is preferably 6 or less, more preferably 3 or less, even more preferably 2 or less, even more preferably 1 or less, and particularly preferably 0. From the viewpoint of thermal decomposition, the aliphatic hydrocarbon group (X) preferably does not have substituents containing hydrocarbon groups, and more preferably does not have substituents.

[0028] Examples of the aliphatic hydrocarbon group (X) include substituted or unsubstituted alkyl groups having 2 to 6 carbon atoms; substituted or unsubstituted alkenyl groups having 2 to 6 carbon atoms; substituted or unsubstituted alkynyl groups having 2 to 6 carbon atoms; and the like. Among these, substituted or unsubstituted alkyl groups having 2 to 6 carbon atoms are preferable from the viewpoints of thermal decomposability and ease of production. Examples of the alkyl group having 2 to 6 carbon atoms include chain alkyl groups such as ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, 3-methylbutyl group, and n-hexyl group; cyclic alkyl groups such as cyclopropyl group, cyclopentyl group, and cyclohexyl group; and the like. Among these, from the viewpoint of thermal decomposability, substituted or unsubstituted chain alkyl groups are preferable, substituted or unsubstituted linear alkyl groups are more preferable, unsubstituted linear alkyl groups are still more preferable, and unsubstituted ethyl groups are even more preferable.

[0029] The main chain of the aliphatic polycarbonate (A) may or may not have a group other than the aliphatic hydrocarbon group (X) as a side chain or a substituent. From the viewpoint of thermal decomposability, the group other than the above aliphatic hydrocarbon group (X) is preferably a group that does not contain a hydrocarbon group having 2 or more carbon atoms. Examples of groups that do not contain a hydrocarbon group having 2 or more carbon atoms include a substituted or unsubstituted methyl group; a substituted or unsubstituted methoxy group; a hydroxy group; a thiol group; a cyano group; an amino group; a silyl group; halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom; and the like. However, from the viewpoint of thermal decomposability, the aliphatic polycarbonate (A) preferably has no groups other than the aliphatic hydrocarbon group (X) directly bonded to the main chain.

[0030] The aliphatic hydrocarbon group (X) is bonded to the main chain directly or via an oxygen atom, and is preferably a group directly bonded to the main chain from the viewpoint of thermal decomposability.

[0031] From the viewpoints of thermal decomposability and dispersion stability, the structural unit having an aliphatic hydrocarbon group (X) in a side chain is preferably a structural unit represented by the following general formula (1).

[0032] (wherein, R １ and R ２ are each independently a hydrogen atom, an aliphatic hydrocarbon group (X) or a group not containing a hydrocarbon group having 2 or more carbon atoms, and all R contained in the structural unit １ and R ２ among which at least one is an aliphatic hydrocarbon group (X). n is an integer of 1 to 10.)

[0033] R １ and R ２ The descriptions of the "aliphatic hydrocarbon group (X)" and "the group not containing a hydrocarbon group having 2 or more carbon atoms" represented by are as described above.

[0034] Among all R contained in the structural unit represented by the above general formula (1) １ and R ２ among which at least one is an aliphatic hydrocarbon group (X); from the viewpoint of thermal decomposability, it is preferable that 1 to 3 are aliphatic hydrocarbon groups (X), more preferable that 1 or 2 are aliphatic hydrocarbon groups (X), and even more preferable that only one is an aliphatic hydrocarbon group (X).

[0035] Among all R contained in the structural unit represented by the above general formula (1) １ and R ２ among those that are not aliphatic hydrocarbon groups (X), it is preferable that all are hydrogen atoms.

[0036] n in the above general formula (1) is an integer of 1 to 10; from the viewpoints of thermal decomposability and dispersion stability, n is preferably 1 to 8, more preferably 2 to 6, still more preferably 2 to 4, even more preferably 2 to 3, and particularly preferably 2.

[0037] The structural unit represented by the above general formula (1) contained in the aliphatic polycarbonate (A) may be a single type alone, or may be two or more types.

[0038] From the viewpoint of thermal decomposition properties and dispersion stability, the structural unit represented by the above general formula (1) is preferably the structural unit represented by the following general formula (1a).

[0039] (In the formula, R １ , R ２ , R ３ and R ４ Each of these is independently a hydrogen atom or an aliphatic hydrocarbon group (X), and R １ , R ２ , R ３ and R ４ Of these, at least one is an aliphatic hydrocarbon group (X).

[0040] From the viewpoint of thermal decomposition properties and dispersion stability, the structural unit represented by the above general formula (1a) is preferably the structural unit represented by the following formula (1a-1) or the structural unit represented by the following formula (1a-2).

[0041]

[0042] Aliphatic polycarbonate (A) may or may not contain structural units other than carbonate units having an aliphatic hydrocarbon group (X) in their side chains. From the viewpoint of thermal decomposition and dispersion stability, the content of carbonate units having an aliphatic hydrocarbon group (X) in their side chains, structural units represented by the above general formula (1), or structural units represented by the above general formula (1a) in aliphatic polycarbonate (A) is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 99 mol% or more, and may be 100 mol%. Note that "total structural units" of aliphatic polycarbonate (A) means the total number of structural units based on one monomer molecule. Structures derived from carbon dioxide are not counted as a single unit; rather, a structure formed from one monomer molecule and one carbon dioxide molecule (i.e., a structure consisting of a divalent hydrocarbon group and a carbonate group (-O-C(=O)-O-) derived from one monomer molecule) is considered a single unit.

[0043] Examples of aliphatic polycarbonates (A) include aliphatic polycarbonates obtained by polymerizing alkylene oxides such as ethylene oxide, propylene oxide, 1,2-butylene oxide, isobutylene oxide, 1-pentene oxide, 2-pentene oxide, 1-hexene oxide, 1-octen oxide, 1-decene oxide, cyclopentene oxide, cyclohexene oxide, and their derivatives, with carbon dioxide. Specific examples of aliphatic polycarbonates (A) include polyethylene carbonate, polypropylene carbonate, polybutylene carbonate, polypentene carbonate, polyhexylene carbonate, polyheptylene carbonate, polyoctylene carbonate, and their derivatives. Among these, polybutylene carbonate is preferred from the viewpoint of thermal decomposition and dispersion stability.

[0044] (Ether bond content of aliphatic polycarbonate (A)) From the viewpoint of improving thermal decomposition properties, aliphatic polycarbonate (A) preferably contains no ether bonds or contains ether bonds, and the content of said ether bonds (hereinafter also simply referred to as "ether ratio") is 20 mol% or less relative to the total amount of carbonate bonds and ether bonds (100 mol%). From a similar viewpoint, the ether bond content in aliphatic polycarbonate (A) is preferably 15 mol% or less, more preferably 10 mol% or less, even more preferably 7 mol% or less, and even more preferably 5 mol% or less, relative to the total amount of carbonate bonds and ether bonds (100 mol%). The ether bond content in aliphatic polycarbonate (A) may be 0 mol%, or it may be 1 mol% or more. Note that the -O- bond in the carbonate bond (-O-C(=O)-O-) does not fall under the category of ether bond. The ether bond content in aliphatic polycarbonate (A) can be measured by the method described in the examples.

[0045] (Elongation at break of aliphatic polycarbonate (A) at 23°C) The elongation at break of aliphatic polycarbonate (A) at 23°C is preferably 1000% or more, more preferably 1200% or more, even more preferably 1400% or more, and even more preferably 1800% or more, from the viewpoint of increasing the flexibility of the resin composition. The elongation at break of aliphatic polycarbonate (A) at 23°C may be, for example, 10000% or less, or 5000% or less. The elongation at break of aliphatic polycarbonate (A) at 23°C can be measured by the method described in the examples.

[0046] (99% thermal decomposition temperature of aliphatic polycarbonate (A)) The 99% thermal decomposition temperature of aliphatic polycarbonate (A) in a nitrogen atmosphere with an oxygen partial pressure of 0.1 kPa or less is preferably 400°C or less, more preferably 380°C or less, even more preferably 350°C or less, and even more preferably 320°C or less. If the 99% thermal decomposition temperature of aliphatic polycarbonate (A) in a nitrogen atmosphere with an oxygen partial pressure of 0.1 kPa or less is below the above upper limit, excellent thermal decomposition properties can be easily obtained in an inert atmosphere. The lower limit of the 99% thermal decomposition temperature of aliphatic polycarbonate (A) in a nitrogen atmosphere with an oxygen partial pressure of 0.1 kPa or less is not particularly limited, but from the viewpoint of suppressing the decomposition of aliphatic polycarbonate (A) in the drying process to remove the solvent from the resin composition, it may be 170°C or higher, 200°C or higher, or 230°C or higher. Furthermore, the 99% pyrolysis temperature in a nitrogen atmosphere with an oxygen partial pressure of 0.1 kPa or less shall be measured by thermogravimetric analysis (TGA) under atmospheric pressure, and specifically, it can be measured by the method described in the examples.

[0047] (Glass transition temperature (Tg) of aliphatic polycarbonate (A)) The glass transition temperature (Tg) of aliphatic polycarbonate (A) is preferably -40 to +25°C, more preferably -30 to +20°C, even more preferably -20 to +15°C, even more preferably -10 to +10°C, and particularly preferably -7 to +7°C, from the viewpoint of easily obtaining high elongation at break. The glass transition temperature (Tg) is measured by differential scanning calorimetry (DSC), and specifically can be measured by the method described in the examples.

[0048] (Content of Aliphatic Polycarbonate (A)) In one embodiment of the resin composition of this embodiment, the content of aliphatic polycarbonate (A) in the resin composition of this embodiment is preferably 1 to 30% by mass, more preferably 1.2 to 25% by mass, even more preferably 1.5 to 20% by mass, and even more preferably 2 to 15% by mass, based on the total mass (100% by mass) of all components other than the solvent. When the content of aliphatic polycarbonate (A) is within the above range, when the resin composition of this embodiment contains sintering particles as described later, it is possible to sufficiently secure the content of sintering particles, and it is also easier to exhibit the effect of aliphatic polycarbonate (A) to enhance the shape retention, flexibility, etc. of the resin composition.

[0049] In one embodiment of the resin composition of this embodiment, the content of aliphatic polycarbonate (A) in the resin composition of this embodiment may be 50 to 100% by mass, 70 to 100% by mass, 90 to 100% by mass, or 95 to 100% by mass, based on the total mass (100% by mass) of all components other than the solvent.

[0050] Aliphatic polycarbonate (A) can be produced by the method described later for producing the resin composition of this embodiment.

[0051] <Solvent> The resin composition of this embodiment preferably further contains a solvent. The resin composition containing a solvent is suitable as a paste-like resin composition. One solvent may be used alone, or two or more solvents may be used in combination.

[0052] Examples of solvents include ketones such as methyl ethyl ketone (2-butanone), methyl isobutyl ketone, cyclohexanone, acetylacetone, and isophorone; ethers such as dioxane and tetrahydrofuran; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated carbons such as dichloromethane and dichloroethane; esters such as methyl acetate, ethyl acetate, and butyl acetate; isopropanol, butanol, cyclohexanol, 1-decanol, and isobornyl. Examples include alcohols such as cyclohexanol; cellosolves such as methyl cellosolve and ethyl cellosolve; glycol ethers or glycol ether acetates such as butyl carbitol, propylene glycol monomethyl ether acetate, butyl carbitol acetate (diethylene glycol monobutyl ether acetate), and ethyl carbitol acetate (diethylene glycol monoethyl ether acetate); cellosolve acetates; sulfoxides such as dimethyl sulfoxide; amides such as dimethylformamide and dimethylacetamide; and so on.

[0053] The solvent content in the resin composition of this embodiment may be adjusted as appropriate depending on the form of the resin composition of this embodiment. If the resin composition of this embodiment contains a solvent, the solvent content is preferably 1 to 40% by mass, more preferably 2 to 35% by mass, even more preferably 3 to 30% by mass, and even more preferably 4 to 25% by mass, based on the total mass (100% by mass) of the resin composition.

[0054] <Sintering Particles> The resin composition of this embodiment is suitable as a resin composition containing sintering particles such as metals and ceramics, and is more suitable as a resin composition containing one or more sintering particles selected from the group consisting of metal oxide precursor particles and metal oxide particles. When the resin composition of this embodiment contains sintering particles, the aliphatic polycarbonate (A) plays a role in improving the shape retention and flexibility of the resin composition as a firing binder. As described above, the resin composition of this embodiment has excellent coating properties, but when the resin composition of this embodiment contains sintering particles, the resin composition of this embodiment can improve flexibility in film form by improving the dispersibility of the sintering particles. Hereinafter, the resin composition of this embodiment containing sintering particles will also be referred to as the "firing resin composition".

[0055] Sintering particles are those that form a sintered body when a sintering resin composition is fired. Metal oxide precursor particles are a general term for substances that can become metal oxides when fired in an oxygen atmosphere. Depending on the intended use of the sintered body, metal oxide precursor particles may be used in a manner that transforms them into metal oxides during the manufacturing process, or they may be used in a manner that forms a sintered body composed of metal oxide precursors without transforming them into metal oxides. Sintering particles may be used individually or in combination of two or more types.

[0056] Examples of metal oxide precursor particles include gold particles, silver particles, copper particles, aluminum particles, nickel particles, tungsten particles, silicon carbide particles, silicon nitride particles, and aluminum nitride particles. Copper particles may consist solely of copper or of a copper alloy. Similarly, aluminum particles may consist solely of aluminum or of an aluminum alloy. Examples of metal oxide particles include oxides of the metal oxide precursor particles described above.

[0057] Average particle size of sintering particles (D ５０ The average particle size (D) of the sintering particles is preferably 0.3 to 15 μm, more preferably 0.8 to 10 μm, and even more preferably 1 to 6 μm. ５０This can be measured, for example, by laser diffraction and scattering methods.

[0058] The content of sintering particles in the firing resin composition is preferably 60 to 99% by mass, more preferably 70 to 98% by mass, even more preferably 80 to 97% by mass, and even more preferably 85 to 96% by mass, based on the total mass (100% by mass) of all components other than the solvent. The total content of aliphatic polycarbonate (A) and sintering particles in the firing resin composition is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, even more preferably 97 to 100% by mass, and even more preferably 99 to 100% by mass, based on the total mass (100% by mass) of all components other than the solvent, and may be 100% by mass.

[0059] <Other Optional Components> The resin composition of this embodiment may contain other optional components besides aliphatic polycarbonate (A), solvent, and sintering particles. Examples of other optional components include resins other than aliphatic polycarbonate (A), dispersants, plasticizers, tackifiers, preservatives, defoamers, thermal decomposition accelerators, antioxidants, sintering aids, and surfactants. Each of these may be used individually or in combination of two or more. These additives can be appropriately selected from those commonly used in this field. Examples of sintering aids include fluorides such as aluminum fluoride, potassium fluoride, and calcium fluoride. Examples of surfactants include betaine-based, sulfobetaine-based, and alkylbetaine-based surfactants. The content of the above optional components in the resin composition of this embodiment is not particularly limited and may be used as needed, within a range that does not hinder the effects of this embodiment. Furthermore, the resin composition of this embodiment may not contain the above optional components, depending on the desired performance.

[0060] The resin composition of this embodiment has excellent coating suitability and flexibility in film form, so it is possible to either not use conventionally used plasticizers or reduce the amount of plasticizers used. Examples of plasticizers include organic acid esters such as phthalates, adipicates, and trimets. From the above viewpoint, the resin composition of this embodiment does not contain organic acid esters, or if it does contain organic acid esters, the content of organic acid esters is preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 4% by mass or less, and even more preferably 1% by mass or less, based on the total mass (100% by mass) of all components of the resin composition other than the solvent. When the resin composition of this embodiment does not contain organic acid esters or the content of organic acid esters is below the above upper limit, the time required for the degreasing process can be shortened, and productivity tends to improve.

[0061] <Form of the resin composition> The resin composition of this embodiment may take the form of a solution, paste, film, etc.

[0062] The thixotropy of the paste-like firing resin composition, expressed as the ratio [η10 / η100] of the viscosity η10 measured at 23°C and 10 rpm to the viscosity η100 measured at 23°C and 100 rpm, is preferably 5.0 or less, more preferably 4.0 or less, even more preferably 3.5 or less, even more preferably 3.0 or less, and particularly preferably 2.5 or less. The thixotropy of the paste-like firing resin composition can be measured by the method described in the examples.

[0063] The elongation at break of the film-like firing resin composition at 23°C is preferably 15% or more, more preferably 20% or more, even more preferably 25% or more, and even more preferably 30% or more. The elongation at break of the film-like firing resin composition at 23°C may be, for example, 100% or less, or 50% or less. The elongation at break of the film-like firing resin composition at 23°C can be measured by the method described in the examples.

[0064] The thickness of the film-like resin composition for firing is not particularly limited and can be determined appropriately depending on the application, but from the viewpoint of film formation properties and versatility, it is preferably 50 to 5000 μm, more preferably 100 to 4000 μm, and even more preferably 200 to 3000 μm.

[0065] <Uses of the Resin Composition> The resin composition of this embodiment is suitable for manufacturing sintered bodies as the above-mentioned firing resin composition. The sintered body manufactured from the resin composition of this embodiment (hereinafter also referred to as "the sintered body of this embodiment") may be an article composed solely of the sintered body of this embodiment, or it may constitute a composite of the sintered body of this embodiment and other components (hereinafter also referred to as "other components").

[0066] The above composite has a structure in which the sintered body of this embodiment and other members are bonded together. For example, it may be a composite body in which two or more other members are joined together by the sintered body of this embodiment, or it may be a composite body in which one other member is bonded to the sintered body of this embodiment.

[0067] Examples of materials for the other components mentioned above include metallic materials such as copper, gold, and aluminum; semiconductor materials such as silicon (Si), germanium, gallium arsenide, gallium phosphide, cadmium sulfide, silicon nitride, graphite, yttrium oxide, magnesium oxide, silicon carbide (SiC), and gallium nitride; plastic materials such as polyimide, polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, and polyethylene naphthalate; and ceramic materials such as glass. Examples of the other components mentioned above include substrates, semiconductor elements, LED elements, leads, frames, and heat sinks.

[0068] The resin composition of this embodiment is not limited to the above-described resin composition for firing, but is also suitable for applications such as temporary fixing materials and biodegradable adhesives.

[0069] <Method for producing the resin composition> The resin composition of this embodiment can be produced by a method that includes a step of producing an aliphatic polycarbonate (A).

[0070] (Process for producing aliphatic polycarbonate (A)) Aliphatic polycarbonate (A) is produced, for example, by carbon dioxide (CO2). ２ It can be produced by polymerizing a monomer that forms a divalent aliphatic hydrocarbon group constituting the main chain. The conditions for the polymerization reaction can be, for example, those described in International Publication No. 2011 / 142259.

[0071] The process for producing aliphatic polycarbonate (A) is preferably a process of polymerizing alkylene oxide and carbon dioxide in the presence of a chain transfer agent, from the viewpoint of making it easier to adjust the PDI of aliphatic polycarbonate (A) to 14 or higher.

[0072] Examples of alkylene oxides include ethylene oxide, propylene oxide, 1,2-butylene oxide, isobutylene oxide, 1-pentene oxide, 2-pentene oxide, 1-hexene oxide, and 1-octene oxide. Among these, 1,2-butylene oxide or derivatives of 1,2-butylene oxide are preferred. Alkylene oxides may be used individually or in combination of two or more.

[0073] Examples of chain transfer agents include alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol, and benzyl alcohol; phenols such as phenol, cresol, catechol, and pyrogallol; carvones such as formic acid, acetic acid, propionic acid, trifluoroacetic acid, succinic acid, adipic acid, glutaric acid, and benzoic acid; inorganic acids such as hydrogen chloride, sulfuric acid, phosphoric acid, and nitric acid; thiols such as methanethiol, ethanethiol, and benzenethiol; hydroxy acids such as glycolic acid, lactic acid, citric acid, malic acid, salicylic acid, gallic acid, and mandelic acid; and water. A single chain transfer agent may be used, or two or more may be used in combination. The amount of chain transfer agent used is preferably 0.1 to 5 mol%, more preferably 0.3 to 2 mol%, based on 100 mol% of the amount of alkylene oxide used.

[0074] When polymerizing alkylene oxide with carbon dioxide, a bifunctional or polyfunctional epoxy compound may be added as a raw material monomer, from the viewpoint of making it easier to adjust the PDI of aliphatic polycarbonate (A) to 14 or higher. Examples of bifunctional or polyfunctional epoxy compounds include 1,4-butanediol diglycidyl ether, erythritol anhydride, 1,3-butadiene diepoxide, 1,5-hexadiene diepoxide, 1,7-octadiene diepoxide, 3-(oxiran-2-yl)-7-oxabicyclo[4.1.0]heptane, polyethylene glycol diglycidyl ether, bis(7-oxabicyclo[4.1.0]heptan-3-ylmethyl) adipate, bis(7-oxabicyclo[4.1.0]heptan-3-carboxylic acid)cyclohexane-1,4-diylbis(methylene), dicyclopentadiene diepoxide, and triglycidyl isocyanurate.

[0075] The polymerization reaction described above is preferably carried out in the presence of a metal catalyst. Examples of metal catalysts include metal salen complex catalysts, complex metal cyanide complex catalysts (DMC catalysts), and organometallic catalysts. Among these, organozinc catalysts are preferred from the viewpoint of exhibiting high polymerization activity and being able to easily adjust the PDI of aliphatic polycarbonate (A) to 14 or higher, and aliphatic zinc dicarboxylate is more preferred as the organozinc catalyst. One type of metal catalyst may be used alone, or two or more types may be used in combination. The amount of metal catalyst used is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 3 parts by mass, per 100 parts by mass of alkylene oxide used.

[0076] The polymerization reaction described above may also use a co-catalyst in addition to the metal catalyst. Examples of co-catalysts include bis(triphenylphosphoranylidene)ammonium chloride, 4-dimethylaminopyridine, tetrabutylammonium chloride, tetrabutylammonium bromide, triphenylphosphine, 1,5,7-triazabicyclo[4.4.0]deca-5-ene, and 1,4-diazabicyclo[2.2.2]octane. One co-catalyst may be used alone, or two or more may be used in combination. The amount of co-catalyst used is preferably 0.001 to 20 parts by mass, more preferably 0.01 to 14 parts by mass, per 100 parts by mass of alkylene oxide.

[0077] The method for carrying out the polymerization reaction is not particularly limited as long as the target product is obtained, but for example, one method involves charging an autoclave with alkylene oxide, a chain transfer agent if necessary, a metal catalyst, a co-catalyst, a polyfunctional epoxy compound, a solvent, etc., mixing them, and then injecting carbon dioxide under pressure into the resulting mixture to carry out the reaction. The solvent used in the polymerization reaction is not particularly limited, but an organic solvent is preferred. The amount of solvent used is preferably 10 to 10,000 parts by mass per 100 parts by mass of alkylene oxide.

[0078] The pressure at which carbon dioxide is injected during the polymerization reaction is preferably 0.1 to 20 MPa, more preferably 0.1 to 10 MPa, and even more preferably 0.1 to 5 MPa. If the pressure at which carbon dioxide is injected is above the lower limit, the polymerization reaction proceeds more easily. Also, if the pressure at which carbon dioxide is injected is below the upper limit, excessive use of carbon dioxide is suppressed, improving economic efficiency.

[0079] The reaction temperature during the polymerization reaction is preferably 20 to 100°C, more preferably 25 to 80°C, from the viewpoint of reaction rate and suppression of side reactions. The reaction time for the polymerization reaction can be adjusted as appropriate according to the reaction temperature, but is preferably 2 to 40 hours.

[0080] During the polymerization reaction, it is preferable to keep the amount of water in the reaction system at 3 mol% or less relative to the amount (moles) of metal catalyst used.

[0081] After the polymerization reaction is complete, the target aliphatic polycarbonate (A) can be isolated by known methods after performing any known post-treatment procedures. The obtained aliphatic polycarbonate (A) may also be purified if necessary.

[0082] If a solution in which aliphatic polycarbonate (A) is dissolved in a solvent is obtained by the above method, the solution can be used as is as the resin composition of this embodiment. Alternatively, if necessary, the aliphatic polycarbonate (A) may be isolated and then mixed with a solvent, sintering particles, and other optional components to produce the resin composition. The method of mixing each component is not particularly limited, and known mixing methods using mixing devices such as a rotary-orbiting agitator, kneader, three-roll mixer, ball mill, sand mill, planetary mixer, paint shaker, homomixer, homodisper, homogenizer, and ultrasonic disperser can be employed.

[0083] A solution-type resin composition can be produced, for example, by mixing an aliphatic polycarbonate (A) and a solvent. A paste-type resin composition can be produced, for example, by mixing an aliphatic polycarbonate (A), sintering particles, and a solvent. A film-type resin composition can be produced, for example, by coating and drying a solution-type resin composition or a paste-type resin composition.

[0084] [Method for Manufacturing a Sintered Body] The method for manufacturing a sintered body according to this embodiment (hereinafter also referred to as "the manufacturing method of this embodiment") is a method for manufacturing a sintered body that involves heating the firing resin composition of this embodiment. The method for manufacturing a sintered body according to this embodiment (hereinafter also referred to as "the manufacturing method of this embodiment") is a method for manufacturing a sintered body that involves heating the firing resin composition of this embodiment.

[0085] In the method for manufacturing a sintered body according to this embodiment, first, the firing resin composition is molded into a desired shape. When manufacturing a layered sintered body, it is preferable to mold it by applying a paste-like firing resin composition to a desired object and then removing the solvent by drying. Examples of such objects include the other members mentioned above. When manufacturing plate-shaped, block-shaped, or other sintered bodies, the firing resin composition can be molded by filling a desired mold or the like. Next, it is preferable to degrease the firing resin composition molded into the desired shape to obtain a sintered body precursor. The degreasing method is not particularly limited, and examples include heating the firing resin composition in a heating furnace. The degreasing temperature is preferably below the 99% thermal decomposition temperature of aliphatic polycarbonate (A). This allows for the thermal decomposition of a portion of the aliphatic polycarbonate (A) to obtain a sintered body precursor. In this embodiment, since the firing resin composition contains aliphatic polycarbonate (A) which has excellent low-temperature decomposition properties, degreasing can be performed at a relatively low temperature. The degreasing temperature may be, for example, 200 to 400°C, 210 to 350°C, or 220 to 300°C. The degreasing time may be appropriately selected to allow sufficient time for the aliphatic polycarbonate (A) to be degreased, for example, 0.05 to 5 hours, 0.07 to 3 hours, or 0.1 to 1 hour.

[0086] The heating atmosphere during degreasing may be an oxygen atmosphere such as air, or an oxygen-free atmosphere, but an oxygen-free atmosphere is preferred from the viewpoint of preventing oxidation of the metal oxide precursor. The partial pressure of oxygen in the oxygen-free atmosphere is preferably 5.0 kPa or less, more preferably 3.0 kPa or less, even more preferably 1.0 kPa or less, even more preferably 0.5 kPa or less, and particularly preferably 0.1 kPa or less, from the viewpoint of preventing oxidation of the metal oxide precursor. Aliphatic polycarbonate (A) exhibits low-temperature decomposition even in an oxygen-free atmosphere, so it can be degreased at a relatively low temperature, thereby preventing oxidation of the metal oxide precursor. The oxygen-free atmosphere may be a single-gas atmosphere, a mixed-gas atmosphere, or a vacuum atmosphere. Examples of single gases include nitrogen, argon, helium, ammonia, and formaldehyde. Examples of mixed gases include forming gases, and examples of forming gases include nitrogen gas mixed with 5 volume% or less of hydrogen. Among these, a nitrogen atmosphere is preferred. The pressure conditions during degreasing may be atmospheric pressure, reduced pressure, or increased pressure.

[0087] Next, the degreased sintered body precursor is fired to obtain a sintered body. The firing method is not particularly limited and includes methods such as heating in a heating furnace.

[0088] In the manufacturing method of this embodiment, the firing temperature is preferably between half and below the melting point (absolute temperature) of the material to be fired. This causes the aliphatic polycarbonate (A) to decompose thermally, and the sintering particles to harden, resulting in a sintered body. The firing time can be appropriately selected to allow the sintering particles to be sufficiently sintered, for example, it may be 0.1 to 48 hours, 1 to 36 hours, or 5 to 24 hours. The sintering atmosphere may be an oxygen atmosphere such as air, or an oxygen-free atmosphere, but an oxygen-free atmosphere is preferred from the viewpoint of preventing oxidation of the metal oxide precursor powder. The preferred form of the oxygen-free atmosphere is the same as the preferred form of the heating atmosphere when degreasing. The pressure conditions of the sintering atmosphere may be atmospheric pressure, reduced pressure, or increased pressure.

[0089] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0090] [Measurement of Number-Average Molecular Weight (Mn) and Mass-Average Molecular Weight (Mw)] The number-average molecular weight (Mn) and mass-average molecular weight (Mw) of the polymers produced in each example were measured using a gel permeation chromatograph (Tosoh Corporation, product name "HLC-8320") under the following conditions, and the measurements were converted to standard polystyrene equivalents. In addition, the molecular weight dispersion (PDI) (Mw / Mn) was calculated from the obtained mass-average molecular weight (Mw) and number-average molecular weight (Mn). <GPC Measurement Conditions> ・Column: A series of "TSK guard column SuperH-H", "TSK gel SuperHM-H", "TSK gel SuperHM-H", and "TSK gel SuperH2000" (all manufactured by Tosoh Corporation) linked together. ・Column temperature: 40°C ・Developing solvent: Tetrahydrofuran (polymer concentration 1% by mass) ・Injection volume: 20 μl ・Flow rate: 0.6 mL / min ・Detector: Differential refractometer ・Standard sample: Polystyrene

[0091] [Measurement of Glass Transition Temperature (Tg)] The glass transition temperature (Tg) of the polymers produced in each example and the comparative polymer was determined by differential scanning calorimetry (DSC) using a DSC Q2000 manufactured by T.A. Instruments Japan Co., Ltd. Specifically, an aluminum pan was used as the container, and under a nitrogen atmosphere, the temperature was increased from -70°C to 150°C at a rate of 10.0°C / min, held for 5 minutes, then cooled to -70°C at a rate of 10.0°C / min, held for 5 minutes, and then increased to 150°C at a rate of 10.0°C / min for measurement. The results are shown in Table 1.

[0092] [Measurement of ether ratio] The polymer produced in each example is used as the measurement target under the following conditions: １ 1H-NMR measurements were performed, and the results were obtained. １In the 1H-NMR spectrum, the integral value A from 4.7 to 5.2 ppm was taken as 1H (one hydrogen), indicating the presence of one carbonate bond, and the integral value B from 3.2 to 3.9 ppm was taken as 3H (three hydrogens), indicating the presence of one ether bond. The ether ratio, which is the content of ether bonds relative to the total amount of carbonate bonds and ether bonds (100 mol%) in each polymer, was calculated using the following formula. The results are shown in Table 1. Ether ratio (mol%) = (B / 3) × 100 / [A + (B / 3)] １ H-NMR measurement conditions: Equipment: Bruker, product name "AV-500" １ H-NMR resonance frequency: 500 MHz Probe: 5 mmφ solution probe Deuterated solvent: Deuterated chloroform (CDCl) ３ ) Internal standard substance: TMS (tetramethylsilane) Sample amount: 20-50 mg Measurement temperature: 25°C Number of cumulative measurements: 16 (Method of preparing measurement samples) The measurement sample was dissolved in deuterated chloroform containing TMS as an internal standard so that the measurement sample concentration was 3% by mass. １ The sample used for 1H-NMR measurement was selected.

[0093] [Synthesis of Metal Catalysts] Production Example 1 (Synthesis of Zinc Glutarate) 160 g of zinc oxide, 249 g of glutaric acid, and 2000 g of zirconia balls were placed in a 1000 mL polypropylene container with a lid in air, and the container was sealed with the lid. The polypropylene container was placed on the rotating rollers of a ball mill stand (manufactured by Ito Seisakusho Co., Ltd., product name "BMU-100") set on a horizontal table, and the reaction was carried out by rotating it at a set rotation speed of 220 rpm at room temperature (23°C) for 5 hours. The zirconia balls were removed by sieving, and the resulting white powder was dried in a vacuum dryer at 120°C for 5 hours to obtain zinc glutarate.

[0094] Preparation Example 2 (Synthesis of Cobalt Salen Complex) (R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-diaminocyclohexanecobalt(II) and pentafluorobenzoic acid were weighed in a molar ratio of 1:1.1 and placed in a flask, to which anhydrous toluene was added. The flask was shielded from light with aluminum foil and reacted at 23°C for 20 hours with stirring. The chemical reaction equation is as follows. After the reaction was complete, the solvent was removed under reduced pressure and washed several times with an excess amount of hexane. Then, the mixture was vacuum dried at 23°C to obtain the cobalt salen complex, which is the product of the chemical reaction equation shown below.

[0095]

[0096] [Production of Resin Composition for Firing] Example 1 (Polymer Synthesis: Polybutylene Carbonate 1) 415 parts by mass of 1,2-butylene oxide as a raw material monomer, 83 parts by mass of zinc glutarate as a polymerization catalyst prepared in Production Example 1, and 4.7 parts by mass of n-butanol as a chain transfer agent were mixed with 1075 parts by mass of toluene to obtain a mixture. Next, the system of a 2 L autoclave equipped with a stirrer, gas inlet pipe and thermometer was pre-filled with a nitrogen atmosphere, and the above mixture was charged in. Subsequently, while stirring the mixture in the autoclave, carbon dioxide gas was filled into the reaction system until the pressure reached 4 MPa. After that, the temperature was raised to 70°C, and the polymerization reaction was carried out for 4 hours while replenishing the carbon dioxide consumed by the reaction. After the reaction was completed, the autoclave was cooled and depressurized, the contents were diluted with toluene, and the catalyst was removed by filtration. The obtained solution was dried under reduced pressure to obtain the product, polybutylene carbonate 1.

[0097] (Preparation of Paste-like Resin Composition for Firing) 100 parts by mass of aluminum nitride powder (manufactured by Tokuyama Corporation, product name "HF-05") as metal oxide precursor particles, 15 parts by mass of the polymer shown in Table 1 as a binder resin, and toluene were blended to adjust the solid content concentration to 70% by mass (Examples 1, 2, Comparative Example 2) or 68% by mass (Comparative Example 1). The mixture was then stirred for 90 seconds using a rotational stirring device (manufactured by Thinky Corporation, product name "ARE-400TWIN") at a rotational speed of 1600 rpm and a rotational speed of 640 rpm. Next, the mixture was stirred again for 90 seconds using the same rotational stirring device at a rotational speed of 1600 rpm and a rotational speed of 640 rpm to obtain a paste-like resin composition for firing.

[0098] (Manufacturing of film-like resin composition for firing) The paste-like resin composition for firing obtained above was coated onto one side of a release film (38 μm thick, manufactured by Lintec Corporation, product name "SP-PET382150") and dried at 150°C for 10 minutes to obtain a film-like resin composition for firing with a thickness of 200 μm on the release film.

[0099] Example 2 (Polymer Synthesis: Polybutylene Carbonate 2) 415 parts by mass of 1,2-butylene oxide as a raw material monomer, 83 parts by mass of zinc glutarate as a polymerization catalyst prepared in Production Example 1, and 3.0 parts by mass of n-butanol as a chain transfer agent were mixed with 1075 parts by mass of toluene to obtain a mixture. Next, the system of a 2 L autoclave equipped with a stirrer, gas inlet pipe and thermometer was pre-filled with a nitrogen atmosphere, and the above mixture was charged in. Subsequently, while stirring the mixture in the autoclave, carbon dioxide gas was filled into the reaction system until the pressure reached 4 MPa. Then, the temperature was raised to 70°C, and the polymerization reaction was carried out for 4 hours while replenishing the carbon dioxide consumed by the reaction. After the reaction was completed, the autoclave was cooled and depressurized, the contents were diluted with toluene, and the catalyst was removed by filtration. The obtained solution was dried under reduced pressure to obtain the product, polybutylene carbonate 2.

[0100] (Production of paste-like and film-like resin compositions for firing) Using the polybutylene carbonate 2 obtained above, a paste-like resin composition for firing and a film-like resin composition for firing with a thickness of 200 μm were produced by the same method as in Example 1.

[0101] Comparative Example 1 (Polymer Synthesis: Polybutylene Carbonate 3) 415 parts by mass of 1,2-butylene oxide as a raw material monomer and 83 parts by mass of zinc glutarate prepared in Production Example 1 as a polymerization catalyst were mixed with 1075 parts by mass of toluene to obtain a mixture. Next, the system of a 2 L autoclave equipped with a stirrer, gas inlet pipe and thermometer was pre-filled with a nitrogen atmosphere, and the above mixture was charged in. Subsequently, while stirring the mixture in the autoclave, carbon dioxide gas was filled into the reaction system until the pressure reached 4 MPa. After that, the temperature was raised to 70°C, and the polymerization reaction was carried out for 4 hours while replenishing the carbon dioxide consumed by the reaction. After the reaction was completed, the autoclave was cooled and depressurized, the contents were diluted with toluene, and the catalyst was removed by filtration. The obtained solution was dried under reduced pressure to obtain the product, polybutylene carbonate 3.

[0102] (Production of paste-like and film-like resin compositions for firing) Using the polybutylene carbonate 3 obtained above, a paste-like resin composition for firing and a film-like resin composition for firing with a thickness of 200 μm were produced by the same method as in Example 1.

[0103] Comparative Example 2 (Polymer Synthesis: Polybutylene Carbonate 4) 1,600 parts by mass of 1,2-butylene oxide as a raw material monomer, 9 parts by mass of cobalt salen complex prepared in Production Example 2 as a polymerization catalyst, and 6.3 parts by mass of bis(triphenylphosphoranylidene)ammonium chloride as a co-catalyst were dissolved in 400 parts by mass of toluene to obtain a mixture. Next, the system of a 4 L autoclave equipped with a stirrer, gas inlet pipe and thermometer was pre-filled with a nitrogen atmosphere, and the above mixture was charged in. Subsequently, while stirring the mixture in the autoclave, carbon dioxide gas was filled into the reaction system until the pressure reached 3 MPa. Then, the temperature was raised to 40°C, and the polymerization reaction was carried out for 5 hours while replenishing the carbon dioxide consumed by the reaction. After the reaction was completed, the autoclave was cooled and depressurized, the contents were diluted with toluene, and the catalyst was removed by reprecipitation purification. The obtained solution was dried under reduced pressure to obtain the product, polybutylene carbonate 4.

[0104] (Production of paste-like and film-like resin compositions for firing) Using the polybutylene carbonate 4 obtained above, a paste-like resin composition for firing and a film-like resin composition with a thickness of 200 μm were produced by the same method as in Example 1.

[0105] Comparative Example 3: Butyral resin (manufactured by Sekisui Chemical Co., Ltd., product name "BL-1") was prepared as a comparative polymer.

[0106] Comparative Example 4: As a comparative polymer, an acrylic resin (manufactured by Kyoeisha Chemical Co., Ltd., product name "Oricox KC-1300") was prepared.

[0107] Comparative Example 5: Ethyl cellulose (manufactured by Dow Chemical Japan Ltd., product name "ETHOCEL Standard 7 Premium") was prepared as a comparative polymer.

[0108] [Evaluation Method] Each polymer and resin composition was evaluated by the following method. The results are shown in Table 1.

[0109] [Evaluation of individual polymers (1): Method for measuring elongation at break] The polymers produced in each example and the comparative polymer were sandwiched between two release films (38 μm thick, manufactured by Lintec Corporation, product name "SP-PET382150") and pressed using a screw-type heater press (manufactured by NPA System Co., Ltd., product name "N4046-00") at 100°C (Examples 1 and 2, Comparative Examples 1, 2 and 4) or 120°C (Comparative Examples 3 and 5) and 4000 N to form a 200 μm thick polymer film with release films on both sides. After removing the release films from both sides of the polymer film obtained above, the film was cut into 10 mm x 50 mm pieces to be used as test specimens. These test specimens were mounted on a tensile testing machine (manufactured by Shimadzu Corporation, product name "Autograph AG-Xplus") with a chuck distance of 30 mm, and the elongation at break was measured at 23°C and a tensile speed of 200 mm / min. In Table 1, the notation ">6000" means that the polymer film did not break when the elongation reached 6000%.

[0110] [Evaluation of individual polymers (2): Pyrolysis test] Using the polymers produced in each example and the comparative polymer as measurement samples, a thermogravimetric analyzer (TGA; manufactured by Shimadzu Corporation, product name "DTG-60") was used to perform a pyrolysis test under the conditions shown below. The temperature at which the mass loss rate of the measurement sample reached 5%, 50%, or 99% was defined as the 5% pyrolysis temperature (T), respectively. ｄ５ ), 50% thermal decomposition temperature (T ｄ５０ ) and 99% thermal decomposition temperature (T ｄ９９ ) was obtained as [a specific result]. In addition, the mass retention rate of the measured sample at 500°C in the pyrolysis test was defined as the 500°C residue rate. (TGA measurement conditions) Heating rate: 10°C / min Sample amount: 20-30 mg Measurement temperature range: 40-500°C Measurement pressure: atmospheric pressure Measurement atmosphere: nitrogen atmosphere with oxygen partial pressure of 0.1 kPa or less

[0111] [Evaluation of Resin Compositions (1): Method for Measuring the Thixometric Index of Paste-Type Casting Resin Compositions] The paste-type casting resin compositions prepared in each example were used as the measurement target. Using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name "RE-85U"), the viscosity measured at 23°C and 10 rpm was set as η10, and the viscosity measured at 23°C and 100 rpm was set as η100. The thixometric index was then calculated using the following formula: Thixometric Index = η10 / η100

[0112] [Evaluation of Resin Compositions (2): Method for Evaluating the Settling Properties of Paste-Type Casting Resin Compositions] The paste-type casting resin compositions prepared in each example were placed in transparent glass containers and left to stand for 24 hours at 23°C. The appearance was observed, and the settling properties of the sintering particles were evaluated based on the following criteria. A: No settling of sintering particles was observed. F: Settling of sintering particles was observed.

[0113] [Evaluation of Resin Compositions (3): Method for Measuring the Elongation at Break of Film-Type Resin Compositions for Firing] The film-type resin composition for firing produced in each example was cut into 10 mm x 50 mm pieces to serve as test specimens. These test specimens were mounted on a tensile testing machine (Shimadzu Corporation, product name "Autograph AG-Xplus") with a chuck distance of 30 mm, and the elongation at break was measured under conditions of 23°C and a tensile speed of 200 mm / min.

[0114] In the table, "-" means that the measurement was not taken. In the table, "*1" means that the mass loss rate did not reach 99% in the thermal decomposition test. In the table, "*2" means that the evaluation was not performed because a paste-like firing resin composition with a solid content of 70% by mass could not be prepared.

[0115] Table 1 shows that the resin composition of this embodiment has excellent coating suitability and flexibility in film form, and can be fired at low temperatures.

Claims

1. A resin composition containing an aliphatic polycarbonate having a molecular weight dispersion (PDI) of 14 or higher, expressed as mass-average molecular weight (Mw) / number-average molecular weight (Mn).

2. The resin composition according to claim 1, wherein the aliphatic polycarbonate has substituted or unsubstituted aliphatic hydrocarbon groups having 2 to 6 carbon atoms in its side chains, either directly or via oxygen atoms to the main chain.

3. The resin composition according to claim 2, wherein the aliphatic polycarbonate is polybutylene carbonate.

4. The resin composition according to any one of claims 1 to 3, wherein the mass-average molecular weight (Mw) of the aliphatic polycarbonate is 200,000 or more.

5. The resin composition according to any one of claims 1 to 3, further comprising one or more sintering particles selected from the group consisting of metal oxide precursor particles and metal oxide particles.

6. The resin composition according to any one of claims 1 to 3, wherein it does not contain organic acid esters, or if it contains organic acid esters, the content of organic acid esters is 10% by mass or less with respect to the total mass (100% by mass) of all components of the resin composition other than the solvent.

7. The resin composition according to claim 5, which is in the form of a paste.

8. The resin composition according to claim 5, which is in the form of a film.

9. A method for producing a resin composition according to any one of claims 1 to 3, comprising the step of polymerizing alkylene oxide and carbon dioxide in the presence of a chain transfer agent to produce an aliphatic polycarbonate.

10. A method for producing a sintered body, comprising heating the resin composition described in claim 5.

11. The method for producing a sintered body according to claim 10, wherein the resin composition is heated in an atmosphere with an oxygen partial pressure of 5.0 kPa or less.

Images