Polyimide molded products

Abstract

This specification provides a polyimide molded article having excellent insulating and mechanical properties useful for electronic components. The polyimide molded article has a dielectric constant of less than 5 and a flexural modulus of at least 7.5 GPa, and is formed from a composition containing (A) at least 30% by weight of at least one layered silicate and (B) at least one polyimide, based on the weight of the polyimide composition.

Description

Technical Field

[0004] , , , , , , , , ,

[0003]

[0001] The present invention relates to an insulating polyimide molded product useful for electronic components. In particular, this insulating polyimide molded product has a low dielectric constant and an excellent flexural modulus, and is formed from a composition containing a large amount of layered silicate and at least one polyimide.

Background Art

[0002] Polyimide compositions are useful in a variety of applications due to the stress and unique performance characteristics of the polyimide composition at high temperatures. The polyimide composition can be processed and used in the form of bushings, seals, piston rings, gears, cams, and thrust plugs.

[0003] However, in applications where greater rigidity characteristics are required, it is difficult to use polyimide compositions due to their mechanical properties. Additives are used to improve the properties of the polyimide composition. For example, U.S. Patent No. 5,789,523 discloses a polyimide composition containing up to 30% by weight of layered silicate to improve wear resistance and frictional properties. International Publication No. 2017 / 197077 pamphlet discloses a polyimide composition containing titanium oxide. However, the polyimide composition disclosed in U.S. Patent No. 5,789,523 focuses on its wear resistance and frictional properties and is not sufficient for the elastic modulus of an article. The polyimide composition disclosed in International Publication No. 2017 / 197077 pamphlet exhibits a high dielectric constant due to the high dielectric properties of titanium dioxide and thus cannot be used as an insulating material. Therefore, ceramics are usually used for this purpose.

Summary of the Invention

Problems to be Solved by the Invention

[0004] While ceramics possess excellent insulation, thermal conductivity, and stability, ceramic articles are heavy, making it difficult to form complex objects. Therefore, there is a need for materials that are easy to process, exhibit low dielectric constant and high flexural modulus. [Means for solving the problem]

[0005] A novel insulating polyimide molded product with a low dielectric constant and a high flexural modulus has been developed.

[0006] The present invention (A) at least one type of polyimide, (B) 30 to 70% by weight of the polyimide composition, at least one layered silicate An insulating polyimide molded article formed from a composition containing, This invention relates to an insulating polyimide molded article having a dielectric constant of less than 5 and a flexural modulus of at least 7.5 GPa. [Modes for carrying out the invention]

[0007] The polyimides used in the composition may contain characteristic -CO-R-CO- groups as linear or heterocyclic units along the main chain of the polymer backbone. Polyimides can be obtained, for example, from the reaction of monomers such as organic tetracarboxylic acids, or their corresponding anhydrides or ester derivatives, with aliphatic or aromatic diamines.

[0008] The polyimide precursor used to prepare the polyimide is an organic polymer that becomes the equivalent polyimide when the polyimide precursor is heated or chemically treated. In certain embodiments of the polyimide thus obtained, about 60 to 100 mole percent, preferably about 70 mole percent or more, and more preferably about 80 mole percent or more of the repeating units of the polymer chain are, for example, the following:

[0009] [ka]

[0010] (In the formula, R1 is a tetravalent aromatic group having 1 to 5 benzenoide unsaturated rings of 6 carbon atoms, with 4 carbonyl groups directly bonded to different carbon atoms in the benzene ring of the R1 group, and each pair of carbonyl groups bonded to adjacent carbon atoms in the benzene ring of the R1 group; R2 is a divalent aromatic group having 1 to 5 benzenoide unsaturated rings of 1 carbon atoms, with 2 amino groups directly bonded to different carbon atoms in the benzene ring of the R2 group.) It has a polyimide structure represented by [the specified formula].

[0011] Preferred polyimide precursors are aromatic, providing polyimides in which the benzene ring of the aromatic compound is directly bonded to the imide group when imidized. Particularly preferred polyimide precursors include, for example, the following general formula:

[0012] [ka]

[0013] (In the formula, R3 is a tetravalent aromatic group having 1 to 5 benzenoide unsaturated rings of 6 carbon atoms, with 4 carbonyl groups directly bonded to different carbon atoms in the benzene ring of the R3 group, and each pair of carbonyl groups bonded to adjacent carbon atoms in the benzene ring of the R3 group; R4 is a divalent aromatic group having 1 to 5 benzenoide unsaturated rings of 1 carbon atoms, with 2 amino groups directly bonded to different carbon atoms in the benzene ring of the R4 group.) The present invention includes a polyamic acid having repeating units represented by , and this polyamic acid may be a homopolymer or a copolymer of two or more repeating units.

[0014] Typical examples of polyamic acids having repeating units represented by the above general formula are those obtained from pyromellitic dianhydride (PMDA) and diaminodiphenyl ether (ODA); and 3,3’,4,4’-biphenyltetracarboxylic dianhydride (BPDA) and ODA. When cyclized, the former becomes poly(4,4’-oxydiphenylene pyromellitimide), and the latter becomes poly(4,4’-oxydiphenylene 3,3’,4,4’-biphenyltetracarboximide).

[0015] Typical examples of polyimides prepared by the solution imidization method are repeating units:

[0016]

Chem.

[0017] (wherein R5 is p-phenylenediamine (PPD)) and is a rigid aromatic polyimide composition having the following structure.

[0018] Another example of a polyimide prepared by the solution imidization method is a rigid aromatic polyimide composition in which R5 is from more than 60 mole percent to about 85 mole percent of PPD units and from about 15 mole percent to less than 40 mole percent of m-phenylenediamine (“MPD”) units.

[0019] The tetracarboxylic acids preferably used in the implementation of the present invention, or the tetracarboxylic acids from which derivatives useful in the implementation of the present invention can be prepared, have the general formula:

[0020]

Chem.

[0021] (wherein A is a tetravalent organic group, and R6 to R9 (both inclusive) are hydrogen or lower alkyl, preferably including methyl, ethyl, or propyl) and have the following structure. The tetravalent organic group A preferably has the following structure:

[0022] [ka]

[0023] (X includes one of the following: -(CO)-, -O-, -S-, -SO2-, -CH2-, -C(CH3)2-, and -C(CF3)2-) It has at least one of the following.

[0024] Aromatic tetracarboxylic acid components include aromatic tetracarboxylic acids, their acid anhydrides, their salts, and their esters. Examples of aromatic tetracarboxylic acids include 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, pyromellitic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)propane, bis(3,4-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl)ether, bis(3,4-dicarboxyphenyl)thioether, bis(3,4-dicarboxyphenyl)phosphine, 2,2-bis(3',4'-dicarboxyphenyl)hexafluoropropane, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, and bis(3,4-dicarboxyphenyl)sulfone.

[0025] These aromatic tetracarboxylic acids can be used individually or in combination. Aromatic tetracarboxylic dianhydrides are preferred, with BPDA, PMDA, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, and mixtures thereof being particularly preferred.

[0026] Preferably, one or more aromatic and / or heterocyclic diamines are used as organic aromatic diamines, and these themselves are known in the art. Such aromatic diamines can be represented by the structure:H2N-R10-NH2 (wherein R10 is an aromatic group containing up to 16 carbon atoms and optionally up to one heteroatom in the ring, the heteroatom including -N-, -O-, or -S-). Also included herein are R10 groups in which R10 is a diphenylene group or a diphenylmethane group.

[0027] Representative examples of such diamines include 2,6-diaminopyridine, 3,5-diaminopyridine, m-phenylenediamine, p-phenylenediamine, ρ,ρ'-methylenedianiline, 2,6-diaminotoluene, and 2,4-diaminotoluene.

[0028] Other examples of aromatic diamine components, which are merely illustrative, include benzenediamines, e.g., 1,4-diaminobenzene, 1,3-diaminobenzene, and 1,2-diaminobenzene; diphenyl(thio)etherdiamines, e.g., 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, and 4,4'-diaminodiphenylthioether; benzophenonediamines, e.g., 3,3'-diaminobenzophenone and 4,4'-diaminobenzophenone; diphenylphosphinediamines, e.g., 3,3'-diaminodiphenylphosphine and These include 4,4'-diaminodiphenylphosphine; diphenylalkylenediamines, e.g., 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, and 4,4'-diaminodiphenylpropane; diphenyl sulfide diamines, e.g., 3,3'-diaminodiphenyl sulfide and 4,4'-diaminodiphenyl sulfide; diphenyl sulfone diamines, e.g., 3,3'-diaminodiphenyl sulfone and 4,4'-diaminodiphenyl sulfone; and benzidines, e.g., benzidine and 3,3'-dimethylbenzidine.

[0029] Other useful diamines have at least one non-heteroatom-containing aromatic ring or at least two aromatic rings bridged by a functional group.

[0030] These aromatic diamines can be used individually or in combination. Preferably, 1,4-diaminobenzene, 1,3-diaminobenzene, 4,4'-diaminodiphenyl ether, and mixtures thereof are used as aromatic diamine components.

[0031] Polyamic acids can be obtained by polymerizing an aromatic diamine component and an aromatic tetracarboxylic acid component in preferably substantially equimolar amounts in an organic polar solvent. The total amount of monomers in the solvent may be in the range of about 5 to about 40 weight percent, more preferably in the range of about 6 to about 35 weight percent, and most preferably in the range of about 8 to about 30 weight percent. The temperature for the reaction is generally about 100°C or less, preferably in the range of about 10°C to 80°C. The time for the polymerization reaction is generally in the range of about 0.2 to 60 hours.

[0032] Furthermore, the method for preparing polyimides can vary depending on the nature of the monomers from which the polymer is produced. For example, when an aliphatic diamine and a tetracarboxylic acid are polymerized, the monomers form a complex salt at ambient temperature. Heating such a reaction mixture at a moderate temperature of about 100 to 150°C yields low molecular weight oligomers (e.g., polyamic acids), which can then be converted into higher molecular weight polymers by further heating at a higher temperature of about 240 to 350°C. When dianhydrides are used as monomers instead of tetracarboxylic acids, solvents such as dimethylacetamide or N-methylpyrrolidinone are typically added to the system. In this case, the aliphatic diamine and dianhydride form oligomers at ambient temperature, and subsequent heating at about 150 to 200°C evaporates the solvent, yielding the corresponding polyimide.

[0033] As described above, aromatic diamines are typically polymerized with dianhydrides, preferentially to tetracarboxylic acids, as an alternative to the use of aliphatic diamines and / or aliphatic diacides or dianhydrides, and in such reactions, catalysts are often used in addition to solvents. Nitrogen-containing bases, phenols, or amphoteric materials can be used as such catalysts. Longer heating times may be required to polymerize aromatic diamines.

[0034] Furthermore, ring closure can be achieved by conventionally used methods such as heat treatment or processes using cyclizing agents such as pyridine and acetic anhydride, picoline and acetic anhydride, or 2,6-lutidine and acetic anhydride.

[0035] The preferred polyimides used herein are infusible polyimides. In some preferred polyimides, essentially all of the linking groups are imide groups. Preferred polyimides include those produced from tetracarboxylic anhydrides (e.g., PMDA and / or BPDA) and about 60 to about 85 mol percent of PPD and about 15 to about 40 mol percent of MPD (see U.S. Patent No. 5,886,129, which is incorporated herein by reference); BPDA and MPD, maleic anhydride and bis(4-aminophenyl)methane; 3,3',4,4'-benzophenone tetracarboxylic dianhydride, toluenediamine and MPD, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, bis(4-aminophenyl)methane and nadoic anhydride; trimellitic anhydride and MPD; trimellitic anhydride and bis(4-aminophenyl) ether; BPDA and bis(4-aminophenyl) ether; BPDA and MPD; BPDA and PPD; 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 4,4'-diaminobenzophenone. Particularly preferred polyimides are tetracarboxylic anhydrides (e.g., PMDA and / or BPDA), about 60 mol% to about 85 mol% of PPD, and about 15 mol% to about 40 mol% of MPD; and / or polyimides produced from PMDA and / or BPDA and ODA.

[0036] The polyimide composition may contain about 30% to about 70% by weight of polyimide powder. In some embodiments, the polyimide composition contains 40%, 50%, 60%, and 70% by weight of polyimide powder. The polyimide powder may be a polyimide polymer which is a rigid polycyclic aromatic polyimide derived from BPDA and PPD.

[0037] In one embodiment, the polyimide composition may contain about 30% to about 70% by weight of polyimide powder, which is a rigid polycyclic aromatic polyimide derived from BPDA and PPD.

[0038] In one embodiment, the polyimide composition may contain about 30% to about 70% by weight of polyimide powder, which is a rigid polycyclic aromatic polyimide derived from BPDA, MPD, and PPD.

[0039] In one embodiment, the polyimide composition may contain about 30% to about 70% by weight of a polyimide polymer, which is a rigid polycyclic aromatic polyimide derived from PMDA and ODA.

[0040] The layered silicates described herein have strong two-dimensional bonds within the silicate layer, but weak interlayer bonds between two or more silicate layers.

[0041] Layered silicates contain Si4+ and may also contain other tetrahedral coordination cations such as Ti4+, Al3+, Fe3+, B3+, P5+, As5+, V5+, Mg2+, Fe2+, Mn2+, Zn2+, and possibly S6+, Cr6+, and Li+. Examples of layered silicates include clay, mica, hydrotalcite, and flaky silica nanoparticles.

[0042] Examples of clays include smectite, halloysite, kanemite, keniite, zirconium phosphate, and titanium phosphate.

[0043] Examples of smectites include montmorillonite, beiderite, nontronite, saponite, hectorite, souconite, and stevensite.

[0044] The layered silicates described herein can be incorporated into the polyimide compositions described herein by adding them at any stage during the preparation of the polyamic acid. The layered silicates may be added to the organic solvent before the introduction of the diamine and dianhydride. Alternatively, they may be added to the organic solvent solution of one or both of the reactants before, during, or after the formation of the polyamic acid. They may also be added to the polyimide powder after it has been precipitated and dried to remove the solvent. In one embodiment, the layered silicate is added to the solution of the polyamic acid.

[0045] The layered silicate can constitute 30% to 70% by weight of the total weight of the polyimide composition (i.e., the sum of polyimide, layered silicate, and other additives, if present), preferably 35% to 70% by weight of the total weight of the polyimide composition. More preferably, the amount of layered silicate is 35% to 65% by weight, and even more preferably 40% to 55% by weight, based on the weight of the polyimide composition.

[0046] When used at a concentration of less than 30% by weight, articles formed from the composition do not achieve a sufficient modulus of elasticity.

[0047] Using amounts exceeding 90% by weight, or in some cases exceeding approximately 70% by weight (approximately 200% by weight based on the weight of the polyimide), tends to weaken the product and limits its usefulness.

[0048] The polyimide composition may contain other additives such as boron nitride, silica, glass fibers, silicon carbide fibers, glass spheres, hollow glass spheres, and Kevlar® powder.

[0049] Articles can be manufactured from polyimide compositions. Any known method can be used. For example, polyimide composition powder can be converted into articles by direct molding (DF) at a pressure of 100,000 psi (689 MPa) at room temperature, followed by sintering in nitrogen at atmospheric pressure at a temperature of up to 420°C for 8 to 150 hours. Alternatively, the polyimide composition powder can be placed in a mold and then heated at a pressure of 1,000 psi to 100,000 psi at a temperature of 250°C to 420°C. The articles can be test socket housings, burn-in socket housings, wafer-level package probe head materials, and chemically mechanically polished retainer rings. [Examples]

[0050] In the examples, the flexural modulus was measured using ASTM D790. The dielectric constant was measured using ASTM D150.

[0051] raw materials Mica: Optifine grade mica, obtained from CB Minerals LLC. Talc: Talcron MP 10-52, obtained from Brenntag North America Inc. Kaolinite: Polyfil (registered trademark) DL, available from KaMin LLC.

[0052] Blending method A: Dry blend Example 1: Polyimide particles (with a molar ratio of BPDA to the total of PPD and MPD of 1:1, and a PPD / MPD ratio of 70 / 30 wt%) were prepared from 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), m-phenylenediamine (MPD), and p-phenylenediamine (PPD) according to the method described in U.S. Patent No. 5,886,129 (specifically Example 1). Then, 46 wt% mica was added to the polyimide particles. The polyimide / mica mixture was performed using a Waring blender at 22,000 rpm for 5 minutes. The prepared rod was measured to have a flexural modulus of 9,700 MPa.

[0053] Example 2: Polyimide particles were prepared according to Example 1 above. Then, 45% by weight of talc was added to the polyimide particles. The polyimide / talc mixture was mixed using a Waring blender at 22,000 rpm for 5 minutes. The prepared rod was measured to have a flexural modulus of 7,800 MPa.

[0054] Example 3: Polyimide particles were prepared according to Example 1 above. Then, 44% by weight of kaolinite was added to the polyimide particles. The polyimide / kaolinite mixture was performed using a Waring blender at 22,000 rpm for 5 minutes. The prepared rod was measured to have a flexural modulus of 10,400 MPa.

[0055] B: Blending in the reactor Example 4: Particles of a polyimide composition containing 55% polyimide (a molar ratio of BPDA to the total of PPD and MPD of 1:1, with a PPD / MPD ratio of 70 / 30 wt%) and 45 wt% talc (Talcron MP10-52 Montana Talc) were prepared according to the method described in U.S. Patent No. 5,886,129 (specifically Example 7). The prepared rods were measured to have a flexural modulus of 11,100 MPa.

[0056] Example 5: Particles of a polyimide composition containing 50% polyimide (a molar ratio of BPDA to the total of PPD and MPD of 1:1, with a PPD / MPD ratio of 70 / 30 wt%) and 50 wt% talc (Talcron MP10-52 Montana Talc) were prepared according to Example 4. The prepared rod was measured to have a flexural modulus of 10,400 MPa.

[0057] Example 6: Particles of a polyimide composition containing 65% polyimide (a molar ratio of BPDA to the total of PPD and MPD of 1:1, with a PPD / MPD ratio of 70 / 30 wt%) and 35 wt% kaolinite, prepared from BPDA, PPD, and MPD, were prepared according to the method described in U.S. Patent No. 5,886,129 (specifically Example 6). The prepared rods were measured to have a flexural modulus of 11.2 MPa.

[0058] Example 7: Particles of a polyimide composition containing 55% polyimide (a molar ratio of BPDA to the total of PPD and MPD of 1:1, with a PPD / MPD ratio of 70 / 30 wt%) and 45% talc (Talcron MP10-52 Montana Talc) were prepared according to Example 6. The prepared rod was measured to have a flexural modulus of 9925 MPa.

[0059] Example 8: Particles of a polyimide composition containing 54% polyimide (a molar ratio of BPDA to the total of PPD and MPD of 1:1, with a PPD / MPD ratio of 70 / 30 wt%) and 46 wt% mica (Optifine, CBM inerals) were prepared according to Example 6. The prepared rod was measured to have a flexural modulus of 10777 MPa.

[0060] Example 9 (Comparative Example): Polyimide particles produced from BPDA, PPD, and MPD (with a molar ratio of BPDA to the total of PPD and MPD of 1:1, and a PPD / MPD ratio of 70 / 30 wt%) were prepared according to the method described in U.S. Patent No. 5,886,129 (specifically Example 1). The prepared rod was measured to have a flexural modulus of 5,800 MPa.

[0061] Molding method Filled polyimide resin powder obtained by either a dry blending or reactor blending process was converted into test specimens by direct molding (DF) at a pressure of 100,000 psi (689 MPa) at room temperature. The resulting parts were sintered in nitrogen at atmospheric pressure at temperatures up to 420°C for 8 to 150 hours. After cooling to room temperature, the parts were machined to the final dimensions of the test specimens. Alternatively, filled polyimide resin powder was converted into test specimens by a hot molding process at a pressure of 1,000 psi to 100,000 psi and a temperature of 250°C to 420°C.

[0062] The flexural modulus and dielectric constant of test specimens formed from the compositions disclosed in Tables 1 and 2 were measured. The results are shown in Table 3.

[0063] [Table 1]

[0064] [Table 2]

[0065] [Table 3]

Claims

1. (A) at least one type of polyimide, (B) 30 to 70% by weight of the polyimide composition, at least one layered silicate An insulating polyimide molded article formed from a composition containing, An insulating polyimide molded article having a dielectric constant of less than 5 and a flexural modulus of at least 7.5 GPa.

2. The insulating polyimide molded article according to claim 1, wherein the layered silicate has strong two-dimensional bonds within the silicate layer and weak bonds between the layers, and has a Mohs hardness of 1 to 5.

3. The insulating polyimide molded article according to claim 1, wherein the layered silicate has a median particle size in the range of 0.15 microns to 100 microns.

4. The insulating polyimide molded article according to claim 1, wherein the layered silicate is selected from the group consisting of muscovite, mica, talc, sepiolite, and kaolinite.

5. The insulating polyimide molded article according to claim 1, wherein the polyimide polymer is a rigid polycyclic aromatic polyimide derived from 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), m-phenylenediamine (MPD), and p-phenylenediamine (PPD).

6. (C) The insulating polyimide molded article according to claim 1, further comprising a filler different from a layered silicate.

7. An insulating polyimide molded article according to claim 1, selected from a test socket housing, a burn-in socket housing, a wafer-level package probe head material, and a chemically mechanically polished retainer ring.

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