Method for evaluating surface resistance uniformity of polyimide molded product, and polyimide molded product having uniform surface resistance

Abstract

The present invention relates to a method for evaluating the surface resistance uniformity of a polyimide molded product, a polyimide molded product comprising a conductive filler, and a manufacturing method therefor. In the present invention, the surface resistance uniformity of a polyimide molded product can be measured using a coefficient of variation of surface resistance values, and a high-quality polyimide molded product having a low average surface resistance and a low coefficient of variation of surface resistance values is provided.

Description

Method for evaluating surface resistance uniformity of polyimide molded articles and polyimide molded articles having uniform surface resistance

[0001] The present invention relates to a method for evaluating the uniformity of surface resistance of a polyimide molded article, a polyimide molded article having uniform surface resistance, and a method for manufacturing the same.

[0002] Generally, polyimide (PI) is a polymer of imide monomers formed by solution polymerization of dianhydrides with diamines or diisocyanates, and possesses mechanical properties such as excellent strength, chemical resistance, weather resistance, and heat resistance based on the chemical stability of the imide ring. In addition, polyimide is gaining attention as a high-performance polymer material applicable to a wide range of industrial fields, such as electronics, telecommunications, or optics, due to its excellent electrical properties, such as insulation properties and low dielectric constant.

[0003] Meanwhile, as mentioned above, polyimide possesses electrical properties such as insulation characteristics and low dielectric constant, but conventional polyimide molded articles have high surface resistance (>10 15 There is a problem that the insulator has a high possibility of charging.

[0004] To lower the high surface resistance of such conventional polyimide molded products, a technology is being developed to introduce conductive fillers during the manufacturing of polyimide powder; however, in this case, there is a problem in that the resistance distribution of the polyimide molded product becomes uneven due to the pressure during molding.

[0005] If the resistance distribution of the polyimide molded product is unbalanced and the coefficient of variation is high, the charge is not dispersed in some areas of the polyimide molded product, which may reduce the antistatic effect.

[0006] In addition, since semiconductor and display production equipment parts manufactured using a portion of polyimide molded products have a direct impact on the quality of semiconductors and displays, if the coefficient of variation of the polyimide molded products is not uniform, it can cause a degradation in the quality of semiconductors and displays.

[0007] Accordingly, there is a need for a method to evaluate the surface resistance uniformity of polyimide molded articles, as well as a polyimide molded article having a uniform resistance distribution, a low coefficient of variation, and an excellent antistatic effect, and a method for manufacturing the same.

[0008]

[0009] [Prior Art Literature]

[0010] [Patent Literature]

[0011] (Patent Document 1) Republic of Korea Published Patent Application No. 10-2016-0103259

[0012] Accordingly, the present invention provides a method for evaluating the uniformity of surface resistance of a polyimide molded article, and aims to provide an antistatic polyimide molded article having uniform surface resistance with a low coefficient of variation of the surface resistance value, and a method for manufacturing the same.

[0013] However, the problems that the present invention aims to solve are not limited to those mentioned above, and other problems not mentioned but intended to be solved will be clearly understood by those skilled in the art to which the present invention belongs from the content to be described below.

[0014] One aspect of the present invention is a method for evaluating the surface resistance uniformity of a polyimide molded article, comprising the step of measuring an average surface resistance value of the polyimide molded article and a coefficient of variation of the surface resistance value.

[0015] The coefficient of variation of the above surface resistance value is calculated using the following Equation 1,

[0016] A method for evaluating the surface resistance uniformity of a polyimide molded article is provided:

[0017]

[0018] [Equation 1]

[0019]

[0020] CV = Coefficient of variation of surface resistance

[0021] σ = standard deviation of surface resistance

[0022] μ = average surface resistance

[0023]

[0024] Another aspect of the present invention is that the coefficient of variation of the surface resistance value measured by the above evaluation method is 2.8 or less, and

[0025] The average surface resistance is 1.0 × 10⁻⁶ 10 Ω or less,

[0026] Provides polyimide molded products.

[0027] Through the method for evaluating the uniformity of surface resistance of a polyimide molded article of the present invention, the coefficient of variation of the surface resistance value of the polyimide molded article can be measured.

[0028] In addition, the polyimide molded articles of the present invention have an average of 1.0 × 10 10 It has a uniform resistance distribution of Ω or less and a low coefficient of variation of surface resistance, so it can have excellent antistatic effects and ensure long-term reliability.

[0029] A semiconductor and display production equipment part manufactured using a portion of a polyimide molded product having a uniform coefficient of variation of surface resistance of the present invention can reduce the defect rate of semiconductors and displays.

[0030] Figure 1 is a schematic representation of measuring the surface resistance value of a polyimide molded article.

[0031] Hereinafter, the operation and effects of the invention will be described in more detail through specific embodiments and drawings. However, these embodiments are merely presented as examples of the invention and do not define the scope of the invention.

[0032] Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0033] Therefore, it should be understood that the configuration of the embodiments described in this specification is merely one of the most preferred embodiments of the present invention and does not represent all of the technical ideas of the present invention, and that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0034] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0035] Where various parameters in this specification are given as an enumeration of ranges, preferred ranges, preferred upper limits, and preferred lower limits, it should be understood that any pair of any upper range limit or preferred value and any lower range limit or preferred value specifically discloses all ranges formed by any pair of any upper range limit or preferred value, regardless of whether the range is disclosed separately.

[0036] Where a range of numerical values ​​is mentioned in this specification, unless otherwise described, the range is intended to include its endpoint and all integers and fractions within the range.

[0037] The scope of the present invention is not intended to be limited to specific values ​​mentioned when defining the scope.

[0038] In the present specification, "a to b" and "a~b" indicating numerical ranges are defined as ≥a and ≤b.

[0039] Embodiments of the present invention have been described in detail below, but the present invention is not limited thereto.

[0040]

[0041] A method for evaluating the uniformity of surface resistance of a polyimide molded article according to one aspect of the present invention may include the step of measuring the average surface resistance value and the coefficient of variation of the surface resistance value of the polyimide molded article.

[0042] At this time, it means that the coefficient of variation of the surface resistance value is calculated using the following Equation 1.

[0043]

[0044] [Equation 1]

[0045]

[0046] CV = Coefficient of variation of surface resistance

[0047] σ Standard deviation of surface resistance value

[0048] μ = average surface resistance

[0049]

[0050] In Equation 1 above, CV may represent the coefficient of variation of the surface resistance value, σ may represent the standard deviation of the surface resistance value, and μ may represent the average surface resistance value.

[0051] At this time, the standard deviation of the surface resistance value can be expressed as Equation 2 below.

[0052]

[0053] [Equation 2]

[0054]

[0055]

[0056] In Equation 2 above, σ can represent the standard deviation of the surface resistance value, x can represent the surface resistance value, μ can represent the average surface resistance value, and N can represent the number of measured resistance values.

[0057] In the present invention, the surface resistance value may refer to the resistance value measured at measurement points. The measurement points may refer to points formed by dividing the sides into equal areas based on the upper and lower surfaces where pressure is applied during the molding of the polyimide molded article.

[0058] That is, the above side can be divided into one or two or more equal areas to measure resistance values ​​for one or multiple measurement points in a polyimide molded product, and for example, the above side can be divided into 10 or more equal areas to set measurement points.

[0059] For example, the above side can be divided into 15 or more, 20 or more, or 25 or more equal areas to set measurement points.

[0060] In one embodiment, the average surface resistance value may mean the average of surface resistance values ​​measured at 25 measurement points in which the side is divided into 25 equal areas based on the upper and lower surfaces where pressure is applied during molding.

[0061] In one embodiment of the present invention, the average surface resistance value of the polyimide molded article is 1.0 × 10 10 It may be Ω or less, and the coefficient of variation of the surface resistance value may be 2.8 or less.

[0062] For example, the upper limit of the average surface resistance value of the polyimide molded article of the present invention is 8.2X10 9 Ω or less, 8.1X10 9 Ω or less or 8.0X10 9 It can be less than Ω.

[0063] For example, the lower limit of the average surface resistance value of the polyimide molded article of the present invention is 1.0×10 3 Ω or greater, 3.0X10 3 Ω or more, 6.0X10 3 Ω or more or 7.0X10 3 It can be greater than Ω.

[0064] A polyimide molded article having the above-mentioned average surface resistance range may be suitable for use in preventing electrostatic discharge (ESD).

[0065] If the above average surface resistance value exceeds the above range, the polyimide molded body acts as an insulator, and there is a high possibility of electric charge.

[0066] For example, the upper limit of the coefficient of variation of the surface resistance value may be 2.8 or less, 2.7 or less, 2.6 or less, 2.5 or less, 2.45 or less, 2.4 or less, 2.35 or less, 2.3 or less, 2.25 or less, 2.0 or less, 1.9 or less, 1.7 or less, 1.6 or less, or 1.55 or less.

[0067] The lower limit of the coefficient of variation of the surface resistance value above may be 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.8 or more, or 1.0 or more.

[0068] In one embodiment of the present invention, the coefficient of variation of the surface resistance value may be 1.22 or higher and 1.51 or lower.

[0069] If the range of the coefficient of variation of the surface resistance value exceeds the above range, it may mean that the polyimide molded product has a relatively non-uniform resistance distribution, and due to the non-uniform resistance distribution, the charge is not dispersed in some areas of the polyimide molded product, so the antistatic effect may be reduced.

[0070] In addition, if the range of the coefficient of variation of the surface resistance value exceeds the above range, it may mean that the quality of the manufactured polyimide molded product is not uniform.

[0071] Therefore, if the coefficient of variation range of the surface resistance value exceeds the above range, it may cause a decrease in the reliability of the polyimide molded product in the long term.

[0072] Meanwhile, if the range of the coefficient of variation of the surface resistance value of the above-mentioned polyimide molded article falls outside the scope of the present invention, the quality of semiconductor and display production equipment parts manufactured using the above-mentioned polyimide molded article may be degraded, and the quality of semiconductors and displays may be degraded due to the use of production equipment parts with degraded quality.

[0073] In one embodiment of the present invention, the polyimide molded article may comprise a polyimide obtained by polymerizing a dianhydride monomer and a diamine monomer.

[0074] In one embodiment of the present invention, the dianhydride monomer may comprise pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA), p-phenylenebis(trimellitate anhydride) (TAHQ), or a combination thereof.

[0075] In one embodiment of the present invention, the diamine monomer is 4,4'-diaminodiphenyl ether (ODA), 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6-diaminotoluene, 4,4'-methylenediamine (MDA), 4,4-diaminobenzanilide (4,4-DABA), N,N-bis(4-aminophenyl)benzene-1,4-dicarboxyamide (BPTPA), 2,2-dimethylbenzidine (M-TOLIDINE), 2,2-bis(trifluoromethyl)benzidine (TFDB), 1,4-bisaminophenoxybenzene (TPE-Q), bisaminophenoxybenzene (TPE-R), 2,2-bisaminophenoxyphenylpropane (BAPP), 2,2-bisaminophenoxyphenylhexafluoropropane (HFBAPP) Or it may include a combination of these.

[0076] For example, the polyimide of the present invention may be obtained by polymerizing pyromellitic dianhydride (PMDA) and 4,4'-diaminodiphenyl ether (ODA).

[0077] In one embodiment of the present invention, the polyimide molded article may include a conductive filler.

[0078] In one embodiment of the present invention, the conductive filler may be a carbon nanotube, graphene, carbon black, or a combination thereof.

[0079] For example, carbon nanotubes, carbon nanotubes and carbon black, or graphene can be used as the conductive filler.

[0080] In one embodiment of the present invention, the conductive filler may be 0.1% by weight or more and 20% by weight or less based on 100% by weight of the total polyimide solid content.

[0081] For example, the conductive filler may be 1.0 wt% or more and 18 wt% or less, 1.5 wt% or more and 16 wt% or less, 2.0 wt% or more and 15 wt% or less, 2.5 wt% or more and 14 wt% or less, 3.0 wt% or more and 13 wt% or less, 3.5 wt% or more and 12 wt% or less, or 4.0 wt% or more and 11 wt% or less, based on 100 wt% of the total weight of the polyimide solids.

[0082] In one embodiment of the present invention, when the carbon nanotube and the carbon black are used as conductive fillers, the weight ratio of the carbon nanotube to the weight of the carbon black (weight of carbon nanotube / weight of carbon black) may be 0.1 to 2.

[0083] For example, the weight ratio of the carbon nanotube to the weight of the carbon black (weight of carbon nanotube / weight of carbon black) may be 0.2 or more and 1.8 or less, 0.3 or more and 1.6 or less, 0.4 or more and 1.4 or less, or 0.5 or more and 1.2 or less.

[0084] For example, since the conductive filler can be used by combining two or more conductive fillers, carbon nanotubes and carbon black may be included in amounts of 3.0 wt% and 5.0 wt%, respectively, based on 100 wt% of the total weight of the polyimide solids.

[0085] One embodiment of the present invention may use carbon nanotubes, graphene, or carbon black alone as a conductive filler.

[0086] For example, a combination of carbon nanotubes and carbon black can be used as a conductive filler, carbon nanotubes alone, or graphene alone.

[0087] At this time, graphene can be used alone as the conductive filler, and the coefficient of variation of the surface resistance value of a polyimide molded article containing graphene alone as the conductive filler may be lower than the coefficient of variation of the surface resistance value of a polyimide molded article using carbon nanotubes alone as the conductive filler.

[0088] A method for manufacturing a polyimide molded article according to one aspect of the present invention may include the steps of: polymerizing the dianhydride monomer and the diamine monomer to prepare a polyamic acid solution; heating the polyamic acid solution to prepare a polyimide mixture; filtering, washing, and drying a precipitate present in the mixture to obtain a polyimide powder; and compression molding the polyimide powder.

[0089] At this time, the polyamic acid solution may contain an organic solvent, and the organic solvent may include N-methyl-2-pyrrolidone (NMP), naphtha, or a combination thereof.

[0090] The step of preparing the polyamic acid solution can be performed at 50°C to 100°C, for example, 60°C to 90°C, 65°C to 85°C, or 70°C to 80°C, and the step of preparing the polyimide mixture can be performed at 160°C to 200°C, for example, 170°C to 190°C, or 175°C to 185°C.

[0091] Since the above heating temperature allows imidization to proceed sufficiently within the range of the present invention, the mechanical properties of the polyimide molded body, such as elongation and tensile strength, or the processability may be excellent. In addition, there is an advantage that mechanical properties, such as elongation and tensile strength, may be excellent because no oxidation phenomenon occurs.

[0092] The step of preparing the polyamic acid solution and / or the step of preparing the polyimide mixture may be performed under pressurized conditions, for example, 1 to 10 bar. In particular, in one embodiment of the present invention, since the dianhydride monomer, diamine monomer, carbon nanotube, and carbon black are dispersed in a mixed solvent for polymerization, the polymerization reaction may be performed at atmospheric pressure or under pressurized conditions of 1 bar to 3 bar or less. Pressurization may be achieved by injecting an inert gas into the reactor or by using water vapor generated inside the reactor. The inert gas may be nitrogen, argon, helium, or neon, etc.

[0093] When the above pressure conditions are within the above range, mechanical properties such as elongation and tensile strength are excellent, and since no fracture occurs during forming, yield and processability can be improved. In addition, since no oxidation occurs, mechanical properties such as elongation and tensile strength can be excellent.

[0094] The reaction time of the step of preparing the polyamic acid solution and / or the step of preparing the polyimide mixture may be 1 to 20 hours, and for example, 1 to 10 hours, 1 to 8 hours, 1 to 6 hours, or 1 to 4 hours.

[0095] If the above reaction time is within the range of the present invention, imidization proceeds sufficiently, and mechanical properties such as elongation and tensile strength, as well as processability, of the polyimide molded body can be improved. In addition, the properties can be maintained without oxidation.

[0096] The step of obtaining the polyimide powder is to obtain the polyimide powder by filtering, washing, and drying the precipitate present in the mixture.

[0097] In one embodiment of the present invention, the polyimide powder may include the conductive filler.

[0098] In one embodiment of the present invention, the conductive filler may be added when preparing the polyamic acid solution. That is, the step of preparing the polyamic acid solution may additionally include the step of adding the conductive filler.

[0099] In one embodiment of the present invention, the conductive filler may be a carbon nanotube, graphene, carbon black, or a combination thereof.

[0100] For example, carbon nanotubes, carbon nanotubes and carbon black, or graphene can be used as the conductive filler.

[0101] The conductive filler in the method for manufacturing a polyimide molded article of the present invention may be 0.1% by weight or more and 20% by weight or less based on 100% by weight of the total solid content of the polyimide.

[0102] For example, the conductive filler may be 1.0 wt% or more and 18 wt% or less, 1.5 wt% or more and 16 wt% or less, 2.0 wt% or more and 15 wt% or less, 2.5 wt% or more and 14 wt% or less, 3.0 wt% or more and 13 wt% or less, 3.5 wt% or more and 12 wt% or less, or 4.0 wt% or more and 11 wt% or less, based on 100 wt% of the total weight of the polyimide solids.

[0103] When the content of the above-mentioned conductive filler is within the range of the present invention, the polyimide molded article has conductivity, and the processability of the polyimide molded article can be improved.

[0104] In addition, since the conductive filler can be used in combination of two or more conductive fillers, for example, carbon nanotubes and carbon black may be included in amounts of 3.0 wt% and 5.0 wt%, respectively, based on 100 wt% of the total weight of the polyimide solids.

[0105] In the method for manufacturing a polyimide molded article of the present invention, the filtration method is not particularly limited, and washing can generally be done with distilled water or alcohol, but is not limited thereto.

[0106] The above drying method is not particularly limited and, for example, can be vacuum dried or oven dried.

[0107] In one embodiment of the present invention, the drying step of the method for manufacturing the polyimide molded article may be performed at a temperature of 150°C or higher and 250°C or lower.

[0108] For example, the temperature of the drying step may be 150°C or higher and 250°C or lower, 160°C or higher and 240°C or lower, 170°C or higher and 230°C or lower, 180°C or higher and 220°C or lower, or 190°C or higher and 210°C or lower.

[0109] If the temperature of the above drying step is within the range of the present invention, the quality of the polyimide molded product manufactured can be improved by sufficiently drying without any residual solvent inside the polyimide molded product, and the mechanical properties of the polyimide molded product manufactured thereafter can be excellent because the polyimide powder is not oxidized.

[0110] In one embodiment of the present invention, the compression molding step of the method for manufacturing the polyimide molded article may be performed at 300°C or higher.

[0111] For example, the temperature of the compression molding step may be 310°C or higher and 500°C or lower, 320°C or higher and 490°C or lower, 330°C or higher and 480°C or lower, 340°C or higher and 470°C or lower, 350°C or higher and 460°C or lower, or 360°C or higher and 450°C or lower.

[0112] In one embodiment of the present invention, the compression molding step of the method for manufacturing the polyimide molded article is 0.5 ton / cm 2 It can be performed as described above.

[0113] For example, the external pressure of the above compression molding step is 0.6 ton / cm 2 More than 5 ton / cm 2 Below, 0.7 ton / cm 2 More than 4 ton / cm 2 Below, 0.8 ton / cm 2 Above 3.5 ton / cm 2 Less than or equal to 0.9 ton / cm 2 More than 3 ton / cm 2 It may be less than.

[0114] In one exemplary embodiment of the present invention, the compression molding step may be performed for 0.5 hours or more.

[0115] For example, the compression molding step may be performed for 0.6 hours or more and 20 hours or less, 0.7 hours or more and 18 hours or less, 0.8 hours or more and 16 hours or less, 0.9 hours or more and 15 hours or less, or 1 hour or more and 14 hours or less.

[0116] In one embodiment of the present invention, the method for manufacturing the polyimide molded article may additionally include a step of post-heat treatment after the compression molding step.

[0117] At this time, the above post-heat treatment can be performed at 230°C or higher.

[0118] For example, the temperature of the above post-heat treatment may be 230°C or higher and 400°C or lower, 240°C or higher and 390°C or lower, 245°C or higher and 380°C or lower, 250°C or higher and 370°C or lower, 255°C or higher and 360°C or lower, or 260°C or higher and 350°C or lower.

[0119] When the temperature of the above post-heat treatment is within the range of the present invention, molecular movement within the manufactured polyimide molded product is smooth, which can improve the uniformity of surface resistance, and the manufactured polyimide molded product is not oxidized by heat, so that cracks do not occur, and thus excellent mechanical properties can be achieved.

[0120] In addition, the above post-heat treatment can be performed for more than 10 hours.

[0121] For example, it can be performed for more than 10 hours and less than 20 hours or more than 11 hours and less than 18 hours, and preferably for 12 hours.

[0122] Through the above post-heat treatment step, stress present within the manufactured polyimide molded product can be relieved, and as a result, the surface resistance value of the polyimide molded product becomes uniform, thereby ensuring excellent antistatic effect and long-term reliability.

[0123] Hereinafter, the operation and effects of the invention will be explained in more detail through specific embodiments of the invention. However, these embodiments are merely presented as examples of the invention and do not define the scope of the invention.

[0124]

[0125] Example 1

[0126] A polyamic acid solution was prepared by sequentially adding 47g of ODA, 3% by weight of carbon nanotubes (CNT) and 3% by weight of carbon black as conductive fillers (based on 100% by weight of the total solid weight of polyimide), and 47g of PMDA to 900g of a mixed solvent of N-methyl-2-pyrrolidone (NMP) and naphtha, and stirring at 75°C for 2 hours. A polyimide mixture was prepared by heating the completed polyamic acid solution at 180°C for 2 hours under atmospheric pressure. The powder precipitated in the mixture was filtered, washed with ethanol, and dried for 24 hours to produce polyimide powder. The prepared powder was then 1 ton / cm³ 2 A polyimide molded article with a thickness of 55 mm was produced by compression molding at 400°C and then post-heat treating at 270°C for 12 hours.

[0127]

[0128] Example 2

[0129] A polyimide molded article was prepared in the same manner as in Example 1, except that the carbon black content was 5% by weight based on 100% by weight of the total weight of the polyimide polymer.

[0130]

[0131] Example 3

[0132] A polyimide molded article was prepared in the same manner as in Example 1, except that carbon black was not added as a conductive filler and the carbon nanotube content was 5% by weight based on 100% by weight of the total weight of the polyimide polymer.

[0133]

[0134] Example 4

[0135] A polyimide molded article was prepared in the same manner as in Example 3, except that graphene was used instead of carbon nanotubes as the conductive filler.

[0136]

[0137] Comparative Example 1

[0138] A polyimide molded article was manufactured in the same manner as in Example 1, except that post-heat treatment was not performed after compression molding.

[0139]

[0140] Comparative Example 2

[0141] A polyimide molded article was manufactured in the same manner as in Example 2, except that post-heat treatment was not performed after compression molding.

[0142]

[0143] Comparative Example 3

[0144] A polyimide molded article was manufactured in the same manner as in Example 3, except that post-heat treatment was not performed after compression molding.

[0145]

[0146] Comparative Example 4

[0147] A polyimide molded article was manufactured in the same manner as in Example 4, except that post-heat treatment was not performed after compression molding.

[0148]

[0149] Evaluation Example 1

[0150] For the polyimide molded articles of Examples 1 to 4 and Comparative Examples 1 to 4, surface resistance was measured at 25 measurement points divided into 25 equal sizes based on the upper and lower surfaces where pressure is applied during molding, and the average surface resistance value was calculated by calculating the average of the measured surface resistance values.

[0151] A schematic diagram of the above measurement points is shown in Figure 1.

[0152] The surface resistance at the center of each measurement point was measured using a resistance meter (Trek, 152-1).

[0153] The average surface resistance values ​​of the examples and comparative examples are shown in Table 1 below.

[0154]

[0155] Average surface resistance (Ω) Example 17.9×10 9 Example 21.2×10 7 Example 38.9×10 4 Example 47.2×10 3 Comparative Example 18.4×10 9 Comparative Example 29.3×10 7 Comparative Example 39.2×10 4 Comparative Example 47.9×10 3

[0156]

[0157] Evaluation Example 2

[0158] The coefficient of variation of the surface resistance value was determined by dividing the standard deviation of the surface resistance value measured in Evaluation Example 1 by the average surface resistance value. The coefficient of variation of the surface resistance value was calculated using Equation 1 below, and the results are shown in Table 2 below.

[0159]

[0160] [Equation 1]

[0161]

[0162]

[0163] CV: Coefficient of variation of surface resistance

[0164] σ: Standard deviation of surface resistance values

[0165] μ: Average surface resistance

[0166]

[0167] Coefficient of variation of surface resistance value Example 11.22 Example 21.25 Example 31.51 Example 41.35 Comparative Example 12.81 Comparative Example 22.88 Comparative Example 32.97 Comparative Example 42.70

[0168]

[0169] According to Evaluation Examples 1 and 2, Examples 1 to 4 underwent a post-heat treatment process after compression molding, and compared to Comparative Examples 1 to 4, which did not undergo separate post-heat treatment, it was confirmed that they had a lower average surface resistance value despite having the same powder composition, while also having a smaller coefficient of variation of the surface resistance value. This means that the molded products of Examples 1 to 4 have superior antistatic effects and long-term reliability compared to the molded products of Comparative Examples 1 to 4.

[0170] In addition, when comparing Example 3 and Example 4, it was confirmed that the coefficient of variation of the surface resistance value is lower when 5 wt% graphene is used instead of 5 wt% carbon nanotubes as the conductive filler.

[0171]

[0172] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

[0173] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

[0174] Through the method for evaluating the uniformity of surface resistance of a polyimide molded article of the present invention, the coefficient of variation of the surface resistance value of the polyimide molded article can be measured.

[0175] In addition, the polyimide molded articles of the present invention have an average of 1.0 × 10 10 It has a uniform resistance distribution of Ω or less and a low coefficient of variation of surface resistance, so it can have excellent antistatic effects and ensure long-term reliability.

[0176] A semiconductor and display production equipment part manufactured using a portion of a polyimide molded product having a uniform coefficient of variation of surface resistance of the present invention can reduce the defect rate of semiconductors and displays.

Claims

1. A method for evaluating the surface resistance uniformity of a polyimide molded article, comprising the step of measuring the average surface resistance value of the polyimide molded article and the coefficient of variation of the surface resistance value, The coefficient of variation of the above surface resistance value is calculated using the following Equation 1, Evaluation method for surface resistance uniformity of polyimide molded articles: [Equation 1] CV = Coefficient of variation of surface resistance σ = standard deviation of surface resistance μ = average surface resistance 2. In Paragraph 1, The above average surface resistance value is the average of surface resistance values ​​measured at 25 measurement points, which are divided into 25 equal areas based on the upper and lower surfaces where pressure is applied during molding. Method for evaluating surface resistance uniformity of polyimide molded articles.

3. The coefficient of variation of the surface resistance value measured by the evaluation method of Paragraph 1 or 2 is 2.8 or less, and The average surface resistance is 1.0 × 10⁻⁶ 10 Ω or less, Polyimide molded product.

4. In Paragraph 3, The coefficient of variation of the above surface resistance value is 1.22 or higher and 1.51 or lower, Polyimide molded product.

5. In Paragraph 3, The above polyimide molded article comprises a polyimide obtained by polymerizing a dianhydride monomer and a diamine monomer, Polyimide molded product.

6. In Paragraph 5, The above dianhydride monomer comprises pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA), p-phenylenebis(trimellitate anhydride) (TAHQ), or a combination thereof, and The above diamine monomer comprises 4,4'-diaminodiphenyl ether (ODA), 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6-diaminotoluene, 4,4'-methylenediamine (MDA), 4,4-diaminobenzanilide (4,4-DABA), N,N'-bis(4-aminophenyl)benzene-1,4-dicarboxyamide (BPTPA), 2,2-dimethylbenzidine (M-TOLIDINE), 2,2-bis(trifluoromethyl)benzidine (TFDB), 1,4-bisaminophenoxybenzene (TPE-Q), bisaminophenoxybenzene (TPE-R), 2,2-bisaminophenoxyphenylpropane (BAPP), 2,2-bisaminophenoxyphenylhexafluoropropane (HFBAPP), or a combination thereof. Polyimide molded product.

7. In Paragraph 3, The above polyimide molded article includes a conductive filler, Polyimide molded product.

8. In Paragraph 7, The above conductive filler is carbon nanotube, graphene, carbon black, or a combination thereof. Polyimide molded product.

9. In Paragraph 7, The above conductive filler is 0.1% by weight or more and 20% by weight or less based on 100% by weight of the total polyimide solid content, Polyimide molded product.

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