Polyimide molded article and method for producing the same

Abstract

To provide a polyimide molded product with excellent thermal dimensional stability, heat resistance, and mechanical properties.SOLUTION: Provided is a polyimide molded product comprising polyimide powder obtained by imidizing an anhydrous acid monomer and a diamine monomer, where a bidirectional coefficient of thermal expansion (CTEBi-direction) according to Formula 1 below in the range of 25°C to 300°C is 0.7 to 1.5. (Formula 1) bidirectional coefficient of thermal expansion (CTEBi-direction=transverse coefficient of thermal expansion (CTEx) / longitudinal coefficient of thermal expansion (CTEy)=CTEx / CTEy.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyimide molded article and a method for producing the same, and more particularly to a polyimide molded article with excellent thermal dimensional stability and a method for producing the same. [Background technology]

[0002] High-heat-resistant polymer materials such as polyimide are indispensable materials for miniaturizing, thinning, improving performance, and increasing reliability of products as advanced technologies develop. They are used in a wide range of industrial fields, including aerospace, aviation, electrical / electronics, automotive, and precision equipment, in the form of films, molded products, fibers, paints, adhesives, and composites. Polyimide possesses excellent mechanical strength, chemical resistance, weather resistance, and heat resistance based on the chemical stability of its imide ring. Furthermore, it is easy to synthesize, can be manufactured as a thin film, has the advantage of not requiring crosslinking groups for curing, and its excellent electrical properties have attracted attention as a high-performance polymer material in fields such as microelectronics and optics.

[0003] In recent years, miniaturization and weight reduction have become crucial in the display field. However, currently used glass substrates have the disadvantages of being heavy, brittle, and difficult to manufacture in a continuous process. Therefore, as an alternative to glass substrates, polyimide substrates, which are lightweight, flexible, and can be manufactured in a continuous process, can be used as insulating films and protective coatings for semiconductor devices, surface protection materials and base resins for flexible circuit boards and integrated circuits, and even for forming interlayer insulating films and protective films for fine circuits. In particular, when used as a coating material, protective materials made by bonding molded polyimide films with adhesives, or liquid polyimide resin solutions can be used.

[0004] The general method for synthesizing polyimides involves first synthesizing a precursor, polyamic acid, by reacting a dianhydride acid with a diamine, and then imidizing the polyamic acid. In the synthesis of polyamic acid, the diamine and dianhydride, dissolved in a solvent, undergo ring-opening and polyaddition reactions to produce polyamic acid. Polar organic solvents are mainly used as the reaction solvent. The synthesized polyamic acid is then dehydrated and ring-closed by chemical or thermal methods to produce polyimide.

[0005] Chemical imidation is a method in which a chemical dehydrating agent, such as an acid anhydride like acetic anhydride, and an imidation catalyst, such as a tertiary amine like pyridine, are added to a polyamic acid precursor solution. However, when further dehydrating agents or catalysts are added to advance the imidation reaction, there are problems such as the cost of the catalyst, the need for an additional catalyst removal step, and low productivity and process efficiency.

[0006] On the other hand, the thermal imidation method involves coating a polyamic acid precursor solution onto a substrate, evaporating the solvent, and then heating it to 250-350°C without a chemical dehydrating agent or catalyst to thermally imidize the polymer. However, this method has the disadvantages of producing a high degree of crystallinity and the decomposition of the polymer due to amide exchange reactions when amide-based solvents are used.

[0007] During the manufacturing process of polyimide molded articles using polyimide powder produced by this method, pressure is applied in one direction (e.g., vertically). However, the residual stress generated during this process causes expansion in the direction of thermal exposure pressure in the final product, which poses a problem in producing high-quality polyimide molded articles. [Overview of the project] [Problems that the invention aims to solve]

[0008] The present invention provides a polyimide molded article with excellent thermal dimensional stability, heat resistance, and mechanical properties.

[0009] Furthermore, the present invention provides a polyimide molded article obtained from the polyimide molded article.

[0010] Furthermore, a method for manufacturing the polyimide molded article is provided. [Means for solving the problem]

[0011] In the following, embodiments of the present invention will be described in more detail, starting with the "polyimide molded article" and then the "method for producing the polyimide molded article."

[0012] Because the present invention can be modified in various ways and has many different embodiments, specific embodiments are illustrated in the drawings and described in detail in the text. However, this should not be understood as limiting the present invention to specific embodiments, but rather as including all modifications, equivalents, or substitutes that fall within the spirit and technical scope of the present invention.

[0013] The terms used in this application are for the sole purpose of describing specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “includes” or “having” are intended to specify the presence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preemptively exclude the presence or possibility of adding one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0014] In this specification, where quantities, concentrations, or other values ​​or parameters are listed as ranges, preferred ranges, preferred upper limits, and preferred lower limits, it should be understood that this specifically discloses all ranges formed by any pair of upper limits or preferred values ​​and any lower limits or preferred values, regardless of whether the ranges are disclosed individually.

[0015] In this specification, when a numerical range is mentioned, unless otherwise specified, the range is intended such that the endpoints thereof and the scope of the present invention within the range are not limited to the specific values mentioned when defining the range.

[0016] In this specification, "dianhydride acid" is intended to include its precursors or derivatives, and may also be referred to as "dianhydride", "dianhydride", or "acid dianhydride". Although these may not technically be dianhydride acids, nevertheless, they react with diamines to form polyamic acids, and these polyamic acids can be converted back to polyimides.

[0017] "Diamine" in this specification is intended to include its precursors or derivatives, and although these may not technically be diamines, nevertheless, they react with dianhydride acids to form polyamic acids, and these polyamic acids can be converted back to polyimides.

[0018] Unless otherwise specified, all terms used in this specification, including technical or scientific terms, shall have the same meaning as commonly understood by those having ordinary knowledge in the technical field to which the present invention pertains. Terms defined as in commonly used dictionaries shall be interpreted as having a meaning consistent with the meaning in the context of the related art, and shall not be interpreted in an ideal or overly formal sense unless clearly defined in the present application. Specific details for the implementation of the above invention are described as follows.

[0019] The present invention provides a polyimide molded body having excellent thermal dimensional stability and a method for producing the same.

[0020] On one side, the polyimide molded body according to the present invention contains one or more dianhydride acid monomers selected from the group consisting of pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride (6FDA), and 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA); and one or more diamine monomers selected from the group consisting of 4,4'-oxydianiline (ODA), p-phenylenediamine (PPD), 1,3-bis(4-aminophenoxy)benzene (TPE-R), 4,4'-methylenedianiline (MDA), 3,5-diaminobenzoic acid (DABA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)benzidine (TFMB), 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), and m-phenylenediamine (MPD); and includes them as polymerization units. In the range of 25°C to 300°C, the coefficient of thermal expansion (CTE x ) in both directions according to the following formula 1 may be 0.7 to 1.5.

[0021] (Formula 1) Coefficient of thermal expansion in both directions (CTE<000000"2">) = Coefficient of thermal expansion in the transverse direction (CTE<000000"3">) / Coefficient of thermal expansion in the longitudinal direction (CTE<000000"4">) = CTE<000000"5"> / CTE<000000"6">

[0022] The coefficient of thermal expansion (CTE<000000"7">) in both directions represented by the above formula 1 is the ratio (CTE<000000"8">) of the coefficient of thermal expansion in the longitudinal direction (CTE<000000"9">) to the coefficient of thermal expansion in the transverse direction (CTE<000000"10"> / CTE<000000"11">Even if the thermal expansion coefficients in the longitudinal and transverse directions of the polyimide molded article are small, if the difference between the thermal expansion coefficient in the longitudinal direction and the thermal expansion coefficient in the transverse direction is large, there is a problem that strain may occur due to the asymmetry of the thermal expansion coefficient when heat is received from the surroundings. In this respect, the polyimide molded article according to one embodiment of the present invention may have thermal expansion coefficients in both directions preferably of 0.75 to 1.3, more preferably of 0.8 to 1.2, even more preferably of 0.9 to 1.1, and most preferably of 0.92 to 1.05.

[0023] The polyimide molded article may have a transverse thermal expansion coefficient of 40 to 60 ppm / °C in the range of 25°C to 300°C, preferably 45 to 55 ppm / °C, more preferably 48 to 53 ppm / °C, and even more preferably 49 to 51 ppm / °C. In one embodiment, it was shown to be 49 ppm / °C, 50 ppm / °C, and 51 ppm / °C. The longitudinal thermal expansion coefficient may be 35 to 65 ppm / °C, preferably 45 to 65 ppm / °C, more preferably 48 to 65 ppm / °C, and even more preferably 50 to 55 ppm / °C. In another embodiment, it was shown to be 50 ppm / °C, 54 ppm / °C, 64 ppm / °C, and 65 ppm / °C. In one embodiment, the thermal expansion coefficient was measured using a TMA apparatus by the ASTM D-696 method.

[0024] The polyimide molded article has a tensile strength of 80 MPa or more, preferably 90 MPa or more, more preferably 95 MPa or more, even more preferably 100 MPa or more, and most preferably 105 MPa or more. There is no particular upper limit, but it may be 200 MPa or less. In one embodiment, the tensile strength was measured using an ASTM D-1708 method with a UTM device.

[0025] The polyimide molded article may have an elongation of 7% or more, preferably 8% or more, more preferably 8.5% or more, even more preferably 9% or more, and most preferably 10% or more. There is no particular upper limit, but it may be 40% or less, 30% or less, or 20% or less. In one embodiment, the elongation was measured using an ASTM D-1708 method with a UTM device.

[0026] The polyimide molded article may have a modulus of 1.5 GPa or higher, preferably 1.7 GPa or higher, more preferably 1.9 GPa or higher, and even more preferably 2.0 GPa or higher. In one embodiment, the modulus was measured using an ASTM D-1708 method with a UTM instrument.

[0027] The polyimide molded articles, in various forms such as films, adhesives, tapes, fibers, and multilayer films, can be applied to a wide range of industrial fields including space, aerospace, electrical / electronics, semiconductors, displays, liquid crystal alignment films, automobiles, precision instruments, packaging, medical materials, separation films, fuel cells, and secondary batteries. They can be widely used in any product or field that is suitable for the physical properties and characteristics of the polyimide molded articles according to the present invention.

[0028] In one aspect, the method for producing a polyimide molded article according to the present invention includes the steps of (a) preparing polyimide powder; (b) molding the polyimide powder to produce a molded article; and (c) post-heat treating the molded article to produce a post-heat treated polyimide molded article, wherein the bidirectional thermal expansion coefficient (CTE) in the range of 25°C to 300°C is determined by the following formula 1. Bi-direction ) may be between 0.7 and 1.5.

[0029] (Formula 1) Coefficient of thermal expansion in both directions (CTE) Bi-direction ) = coefficient of thermal expansion in the lateral direction (CTE) x ) / Coefficient of thermal expansion in the vertical direction (CTE y )=CTE x / CTE y

[0030] In step (c), the post-heat treatment can be carried out at a temperature near the glass transition temperature of the polyimide, and preferably can be carried out within the temperature range according to the following formula 2. At this time, the glass transition temperature of the polyimide may be 250°C to 400°C.

[0031] (Formula 2) Tg - 100°C < T < Tg + 100°C (T is the post-heat treatment temperature, Tg is the glass transition temperature of the polyimide)

[0032] [[ID=A]]The post-heat treatment temperature is preferably 200 to 400°C, more preferably 250 to 400°C, and even more preferably 300 to 400°C. If the post-heat treatment temperature is less than 200°C, it is difficult to eliminate the residual stress, and it is difficult to control the CTE in both directions, so it is not preferable. If it exceeds 400°C, the physical properties of the polyimide molded body will deteriorate, so it is not preferable.

[0033] In step (c), the post-heat treatment can be carried out for 30 minutes to 180 hours, preferably 1 to 36 hours, more preferably 3 to 30 hours, and even more preferably 6 to 24 hours.

[0034] Step (c) may be a step of post-heat treating the molded body to remove the residual stress inside the molded body.

[0035] The polyimide powder can contain a dianhydride acid monomer; and a diamine monomer; as polymerization units.

[0036] The aforementioned dianhydride acid monomers are pyromeretic dianehydride (PMDA), oxydiphthalic dianehydride (ODPA), 3,3',4,4'-biphenyltetracarboxylic dianehydride (BPDA), 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride (6FDA), 2,3,3',4'-biphenyltetracarboxylic dianehydride (a-BPDA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianehydride (DSDA), and bis(3,4-dicarboxyf (Nyl) sulfide dianehydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropanedianehydride, 2,3,3',4'-benzophenone tetracarboxylic dianehydride, 3,3',4,4'-benzophenone tetracarboxylic dianehydride (BTDA), bis(3,4-dicarboxyphenyl)methanedianehydride, 2,2-bis(3,4-dicarboxyphenyl)propanedianehydride, p-phenylenebis(trimeltic monoester acetate (Biphenylene bi(trimeric monoester acid anhydride), p-biphenylenebis(trimeric monoester acid anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianehydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianehydride, 1,3-bis(3,4-dicarboxyphenoxy)benzenedianehydride, 1,4-bis(3,4-dicarboxyphenoxy)benzenedianehydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyldianehydride, 2,2-bis[ It may contain one or more selected from the group consisting of (3,4-dicarboxyphenoxy)phenyl]propanedianehydride (BPADA), 2,3,6,7-naphthalenetetracarboxylate dianehydride, 1,4,5,8-naphthalenetetracarboxylic dianehydride and 4,4'-(2,2-hexafluoroiropropylidene)diphthalic acid dianehydride, preferably pyromeretic dianehydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianehydride (BPDA), 3,3',The present invention may include one or more dianhydride selected from the group consisting of 4,4'-benzophenone tetracarboxylic dianehydride (BTDA), oxydiphthalic dianehydride (ODPA), 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride (6FDA), and 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propanedianehydride (BPADA). The range of dianhydride monomers of the present invention is not limited thereto, and a wide range of dianhydrides used in polyimide production can be used.

[0037] The diamine monomers are p-phenylenediamine (PPD), m-phenylenediamine (MPD), 4,4'-methylenedianiline (MDA), 2,2'-bis(trifluoromethyl)benzidine (TFMB), 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 4,4'-oxydianiline (ODA), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenyl meta (methylenediamine), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4-aminophenyl) sulfide, 4,4'-diaminobenzanilide, 3,3'-dimethoxybenzidine, 2,2'-dimeth Xybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'- Diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-Diaminodiphenyl sulfoxide, 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,4-bis(3-aminophenoxy)benzene (TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenyl sulfide)benzene, 1,3 -Bis(4-aminophenylsulfide)benzene, 1,4-bis(4-aminophenylsulfide)benzene, 1,3-bis(3-aminophenylsulfone)benzene, 1,3-bis(4-aminophenylsulfone)benzene, 1,4-bis(4-aminophenylsulfone)benzene, 1,3-bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-bis[2-(3-aminophenyl)isopropyl]benzene, 1,4-bis[2-(4-aminophenyl)isopropyl]benzene, 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-Bis(4-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl] ether, bis[3-(4-aminophenoxy)phenyl] ether, bis[4-(3-aminophenoxy)phenyl] ether, bis[4-(4-aminophenoxy)phenyl] ether, bis[3-(3-aminophenoxy)phenyl] ketone, bis[3-(4-aminophenoxy)phenyl] ketone, bis[4-(3-aminophenoxy)phenyl] ketone, bis[3-(3-amino Phenoxy)phenyl]sulfide, bis[3-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl] [Phenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, It may contain one or more selected from the group consisting of 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), preferably 4,4'-oxydianiline (ODA), p-phenylenediamine (PPD), 1,3-bis(4-aminophenoxy)benzene (TPE-R), 4,The present invention may include one or more diamine monomers selected from the group consisting of 4'-methylenedianiline (MDA), 3,5-diaminobenzoic acid (DABA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)benzidine (TFMB), 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), and m-phenylenediamine (MPD). The range of diamine monomers of the present invention is not limited thereto, and a wide range of diamines used in the production of polyimides can be used.

[0038] In one example, pyromeretic dianehydride (PMDA) is used as the dianhydride monomer, and 4,4'-oxydianiline (ODA) is used as the diamine monomer. After polymerization at 60-100°C, the mixture is pulverized by heat treatment at 150°C or higher to produce polyimide powder.

[0039] The polyimide powder may have a solid content of 5 to 20% by weight, preferably 10 to 15% by weight.

[0040] The content of the dianhydride acid monomer can be 90 mol% to 100 mol%, preferably 95 to 100 mol%, and more preferably 100 mol%.

[0041] The content of the diamine monomer can be 90 mol% to 100 mol%, preferably 95 to 100 mol%, and more preferably 100 mol%.

[0042] The molar ratio of the dianhydride monomer to the diamine monomer can be 1:0.9 to 1:1.1, preferably 1:0.95 to 1:1.05, and more preferably 1:1.

[0043] The polyimide powder is selected from the group consisting of all aromatic polyimides, partially alicyclic polyimides, and fully alicyclic polyimides. It can be either one.

[0044] In step (b), the molding can be carried out by one or more methods selected from the group consisting of compression molding, thermal compression molding, injection molding, hollow molding, rotational molding, extrusion molding, thermoforming, slush molding, and spinning molding.

[0045] Furthermore, polyimide molded articles produced by the method for producing polyimide molded articles according to the present invention exhibit excellent thermal dimensional stability and can maintain all physical properties such as tensile strength, elongation, and modulus to an excellent degree, making them applicable to a wide range of fields where such properties are required.

[0046] The manufactured molded products, in various forms such as films, adhesives, tapes, fibers, and multilayer films, can be applied to a wide range of industrial fields including aerospace, aviation, electrical / electronics, semiconductors, displays, automobiles, precision instruments, packaging, medical materials, separator membranes, fuel cells, and secondary batteries. [Effects of the Invention]

[0047] The present invention provides a polyimide molded article and a method for producing the same, which removes residual stress inside the molded article by a separate post-heat treatment. This allows for the production of a polyimide molded article with low thermal expansion in both the longitudinal and transverse directions and excellent thermal dimensional stability. The polyimide molded article also exhibits excellent mechanical properties such as tensile strength, elongation, and modulus. [Modes for carrying out the invention]

[0048] Examples are provided to aid in understanding the present invention. The following examples are provided solely to facilitate understanding of the present invention and do not limit the scope of the invention.

[0049] The polyimide molded article of the present invention comprises a dianhydride acid monomer containing one or more selected from the group consisting of pyromeretic dianehydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianehydride (BPDA), 3,3',4,4'-benzophenonetetracarboxylic dianehydride (BTDA), oxydiphthalic dianehydride (ODPA), 4,4'-(hexafluoroisopropylidene)diphthalic acid dianehydride (6FDA), and 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propanedianehydride (BPADA); and The product contains a polyimide powder obtained by imidizing a diamine monomer containing one or more selected from the group consisting of 4,4'-oxydianiline (ODA), p-phenylenediamine (PPD), 1,3-bis(4-aminophenoxy)benzene (TPE-R), 4,4'-methylenedianiline (MDA), 3,5-diaminobenzoic acid (DABA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)benzidine (TFMB), 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), and m-phenylenediamine (MPD). In the range of 25°C to 300°C, the coefficient of thermal expansion in both directions (CTE) is given by the following equation 1. Bi-direction ) is between 0.7 and 1.5.

[0050] Furthermore, the method for producing the polyimide molded article of the present invention is as follows: (a) The step of preparing the polyimide powder; (b) the step of molding the polyimide powder to produce a molded article; and (c) The step of post-heat-treating the molded body to produce a post-heat-treated polyimide molded body; The post-heat-treated polyimide molded article exhibits a bidirectional thermal expansion coefficient (CTE) in the range of 25°C to 300°C, according to the following formula 1. Bi-direction ) is between 0.7 and 1.5.

[0051] (Formula 1) Coefficient of thermal expansion in both directions (CTE)Bi-direction ) = coefficient of thermal expansion in the lateral direction (CTE) x ) / Coefficient of thermal expansion in the vertical direction (CTE y )=CTE x / CTE y [Examples]

[0052] [Manufacturing Example 1] Polyimide Powder Manufacturing A polyamic acid composition was prepared by dispersing pyromeretic dianehydride (PMDA, 100 mol%), a dianhydride acid compound, and 4,4'-oxydianiline (ODA, 100 mol%), a diamine compound, in the solvents N-methylpyrrolidone and naphtha.

[0053] The polyamic acid composition was transferred to a 500 mL reaction vessel equipped with a stirrer, a nitrogen injection device, and a temperature controller. The air in the reaction vessel was then replaced with nitrogen gas, and the mixture was stirred at 180°C for 6 hours in a high-temperature reactor to produce a polyimide powder suspension.

[0054] The polyimide powder suspension was washed with distilled water and filtered under reduced pressure to obtain the undried polyimide powder, which was then dried in a vacuum oven at 200°C for 24 hours to obtain polyimide powder.

[0055] [Manufacturing of polyimide molded products] [Example 1] The polyimide powders produced according to Production Example 1 were weighed into molds for physical property evaluation and measured at 0.5 ton / cm³ using a hot press. 2 The molded body was manufactured by heating to 400°C while applying the above pressure. Subsequently, the molded body was heat-treated in an oven at 300°C for 6 hours to produce the final polyimide molded body (width 100 mm, length 100 mm, thickness 30 mm). m m)

[0056] [Example 2] A polyimide molded article was manufactured in the same manner as in Example 1, except that the heat treatment was performed at 350°C for 6 hours instead of 300°C for 6 hours.

[0057] [Example 3] A polyimide molded article was manufactured in the same manner as in Example 1, except that the heat treatment was performed at 400°C for 6 hours instead of 300°C for 6 hours.

[0058] [Example 4] A polyimide molded article was manufactured in the same manner as in Example 1, except that the heat treatment was performed at 400°C for 24 hours instead of 300°C for 6 hours.

[0059] [Example 5] A polyimide molded article was manufactured in the same manner as in Example 1, except that the heat treatment was performed at 200°C for 6 hours instead of 300°C for 6 hours.

[0060] [Example 6] A polyimide molded article was manufactured in the same manner as in Example 1, except that the heat treatment was performed at 250°C for 6 hours instead of 300°C for 6 hours.

[0061] [Comparative Example 1] A polyimide molded article was manufactured in the same manner as in Example 1, except that the step of heat treatment at 300°C for 6 hours was omitted.

[0062] [Comparative Example 2] A polyimide molded article was manufactured in the same manner as in Example 1, except that the heat treatment was performed at 450°C for 6 hours instead of 300°C for 6 hours.

[0063] The post-heat treatment conditions for the polyimide molded articles in Examples 1-6, Comparative Example 1, and Comparative Example 2 are summarized in Table 1 below.

[0064] [Table 1]

[0065] [Experimental Example 1] Analysis of the properties of polyimide molded products (1) Tensile strength The tensile strength of the polyimide molded articles produced in the examples and comparative examples was measured using a universal material testing machine (model name Instron 5564, Instron Corporation) according to the method presented in ASTM D1708. The results are shown in Table 2 below.

[0066] (2) Elongation The elongation of the polyimide molded articles produced in the examples and comparative examples was measured using the ASTM D-1708 method with an Instron 5564 UTM instrument from Instron. The results are shown in Table 2 below.

[0067] (3) Modulus (elastic modulus) The modulus of the polyimide molded articles produced in the examples and comparative examples was measured using the ASTM D-1708 method with an Instron 5564 model. The results are shown in Table 2 below.

[0068] (4) Coefficient of thermal expansion The thermal expansion coefficients (CTE) in the transverse (x) and longitudinal (y) directions in the range of 50 to 200°C were measured for the polyimide molded articles produced in the examples and comparative examples using a TMA apparatus according to ASTM D-696. x ) and the coefficient of thermal expansion in the vertical direction (CTE) y ) from the coefficient of thermal expansion in both directions (CTE x / CTE y The calculation was performed. The results are shown in Table 2 below.

[0069] The tensile strength, elongation, modulus of elasticity, and coefficient of thermal expansion of the polyimide molded articles for the examples and comparative examples are shown in Table 2 below.

[0070] [Table 2]

[0071] According to Table 2, Examples 1-6, which underwent post-heat treatment, had a lower lateral thermal expansion coefficient (CTE) compared to Comparative Example 1, which did not undergo post-heat treatment. x ) and the coefficient of thermal expansion in the vertical direction (CTE)y Since the difference in ) is not large, the ratio (CTE x / CTE y It was confirmed that the value was close to 1. This means that the residual stress generated by the pressure applied in the vertical direction (one direction) when the polyimide powder was molded into the molded body was removed by post-heat treatment, ensuring heat-resistant dimensional stability.

[0072] Furthermore, Examples 1 to 6, which underwent post-heat treatment in the temperature range of 200 to 400°C, showed superior tensile strength, elongation, and modulus compared to Comparative Example 2, which underwent post-heat treatment at 450°C. This indicates that post-heat treatment at high temperatures such as 450°C can actually degrade the physical properties of polyimide molded articles.

[0073] Therefore, it has been found that the polyimide molded article according to the present invention has excellent mechanical properties while ensuring heat-resistant dimensional stability through post-heat treatment within an appropriate temperature range.

[0074] This specification omits detailed descriptions of matters that can be easily understood and inferred by a person with ordinary skill in the art of the present invention, and allows for a wider variety of modifications without altering the technical idea or essential components of the present invention, beyond the specific examples provided herein. Therefore, the present invention can be implemented in ways different from those specifically described and illustrated herein, and this is something that can be understood by a person with ordinary skill in the art of the present invention.

Claims

1. Dianhydride acid monomers comprising one or more selected from the group consisting of pyromeretic dianehydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianehydride (BTDA), oxydiphthalic dianehydride (ODPA), 4,4'-(hexafluoroisopropylidene)diphthalic acid dianehydride (6FDA), and 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propanedianehydride (BPADA); and, The present invention comprises a polyimide powder obtained by imidizing a diamine monomer containing one or more selected from the group consisting of 4,4'-oxydianiline (ODA), 1,3-bis(4-aminophenoxy)benzene (TPE-R), 4,4'-methylenedianiline (MDA), 3,5-diaminobenzoic acid (DABA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)benzidine (TFMB), and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP). In the range of 25°C to 300°C, the coefficient of thermal expansion in both directions (CTE) is given by the following equation 1. Ｂｉ－ｄｉｒｅｃｔｉｏｎ A polyimide molded article having a ratio of 0.7 to 1.5, The polyimide molded article has a tensile strength of 95 MPa or more, an elongation of 7% or more, and a modulus of 1.5 GPa or more. (Formula 1) Coefficient of thermal expansion in both directions (CTE) Ｂｉ－ｄｉｒｅｃｔｉｏｎ ) = coefficient of thermal expansion in the lateral direction (CTE) ｘ ) / Coefficient of thermal expansion in the vertical direction (CTE) ｙ ) = CTE ｘ / CTE ｙ In Equation 1, The aforementioned lateral direction refers to the direction of pressure. The aforementioned vertical direction refers to the direction perpendicular to the pressure direction.

2. The polyimide molded article according to claim 1, wherein the coefficient of thermal expansion in the lateral direction is 40 to 60 ppm / °C and the coefficient of thermal expansion in the vertical direction is 35 to 65 ppm / °C in the range of 25°C to 300°C.

3. The polyimide molded article according to claim 1, wherein the polyimide molded article has a tensile strength of 105 MPa or more, an elongation of 7% or more, and a modulus of 1.5 GPa or more.

4. (a) A step of preparing a polyimide powder containing dianhydride monomers and diamine monomers as polymerization units; (b) The step of molding the polyimide powder to produce a molded article; and (c) The step of post-heat-treating the molded body to produce a post-heat-treated polyimide molded body; Here, the dianhydride acid monomer includes one or more selected from the group consisting of pyromeretic dianehydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianehydride (BTDA), oxydiphthalic dianehydride (ODPA), 4,4'-(hexafluoroisopropylidene)diphthalic acid dianehydride (6FDA), and 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propanedianehydride (BPADA). The diamine monomer comprises one or more selected from the group consisting of 4,4'-oxydianiline (ODA), 1,3-bis(4-aminophenoxy)benzene (TPE-R), 4,4'-methylenedianiline (MDA), 3,5-diaminobenzoic acid (DABA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)benzidine (TFMB), and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP). The aforementioned post-heat treatment is carried out at a temperature of 200 to 400°C. The post-heat-treated polyimide molded article exhibits a bidirectional thermal expansion coefficient (CTE) in the range of 25°C to 300°C, according to the following formula 1. Ｂｉ－ｄｉｒｅｃｔｉｏｎ ) is between 0.7 and 1.5, A method for manufacturing a polyimide molded article, wherein the polyimide molded article has a tensile strength of 95 MPa or more, an elongation of 7% or more, and a modulus of 1.5 GPa or more. (Formula 1) Coefficient of thermal expansion (CTE) in both directions Ｂｉ－ｄｉｒｅｃｔｉｏｎ = Coefficient of thermal expansion (CTE) in the transverse direction ｘ / Coefficient of thermal expansion (CTE) in the longitudinal direction ｙ = CTE ｘ / CTE ｙ In Equation 1, The aforementioned lateral direction refers to the direction of pressure. The aforementioned vertical direction refers to the direction perpendicular to the pressure direction.

5. The method for producing a polyimide molded article according to claim 4, wherein the post-heat treatment is performed for 30 minutes to 180 hours.

6. The method for producing a polyimide molded article according to claim 4, wherein (c) is a step of post-heat treatment of the molded article to remove residual stress inside the molded article.

7. The method for producing a polyimide molded article according to claim 4, wherein the polyimide powder is selected from the group consisting of all aromatic polyimides, partially alicyclic polyimides, and fully alicyclic polyimides.

8. The method for producing a polyimide molded article according to claim 4, wherein in step (b), the molding is carried out by one or more methods selected from the group consisting of compression molding, thermal compression molding, injection molding, hollow molding, rotational molding, extrusion molding, thermoforming, slush molding, and spinning molding.

9. A method for producing a polyimide molded article according to claim 4, wherein the coefficient of thermal expansion in the lateral direction is 40 to 60 ppm / °C and the coefficient of thermal expansion in the vertical direction is 35 to 65 ppm / °C in the range of 25°C to 300°C.

10. The method for producing a polyimide molded article according to claim 4, wherein the polyimide molded article has a tensile strength of 105 MPa or more, an elongation of 7% or more, and a modulus of 1.5 GPa or more.

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