Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
  • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
  • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
  • C08G73/1003—Preparatory processes
  • C08G73/1007—Preparatory processes from tetracarboxylic acids or derivatives and diamines
  • C08G73/101—Preparatory processes from tetracarboxylic acids or derivatives and diamines containing chain terminating or branching agents
  • C08G73/1017—Preparatory processes from tetracarboxylic acids or derivatives and diamines containing chain terminating or branching agents in the form of (mono)amine

Definitions

• the present invention relates to a PMR-type polyimide having excellent storage stability. More particularly, it relates to a PMR-type polyimide which is suitable as a matrix resin having good storage stability of a varnish and high mechanical properties of a fiber-reinforced composite material. . Background technology
• Polycondensation-type polyimides become insoluble in organic solvents as the degree of polymerization increases, so when used as a matrix resin for composite materials, so-called amide acids before dehydration and ring closure
• amide acids before dehydration and ring closure
• a method of dissolving in a high boiling point solvent such as n-methylvillidone (NMP) or dimethylformamide (DMF) and impregnating the reinforced textile
• NMP n-methylvillidone
• DMF dimethylformamide
• addition-curable polyimide is an oligomer having a molecular weight of about 1500 and having an addition-reactive nadic acid at the end, and is converted into a polyimide polymer through an amido acid prepolymer. Thermosetting, which is crosslinked by ring-opening addition reaction of the terminal nadic acid Resin.
• addition-curable polyimides also have the problem of dissolving only in high-boiling solvents such as NMP and DMP. Therefore, as a result of research on improving the solubility, carboxylic anhydride-type monomers were obtained. Is esterified with alcohol and the alcohol is used as a solvent.
• PMR-type polyimid in-situ Polymerization of Monomeric Reactants
• swords are available at TRW Systems, Inc.
• TRW Systems, Inc. Journal of Applied Polymer Science (J.Appl.Polym.Sci.), 16, (1972), 905]
• PMR-type polyimid is based on conventional polyimid. It is characterized in that a varnish is prepared by dissolving a monomer in a low-boiling solvent, whereas a varnish is prepared by dissolving an amide acid prepolymer in a high-boiling solvent.
• a typical resin in the imid 15 is a monomer such as 3,3 ', 4,4'-dimethylbenzoic acid benzoate (BTDE), monomethyl ester of nadic acid (NE) and 4,4'-diamino diphenyl methane (DDM)
• BTDE 4,4'-dimethylbenzoic acid benzoate
• NE monomethyl ester of nadic acid
• DDM 4,4'-diamino diphenyl methane
• the varnish is prepared by dissolving the varnish directly in methanol, and the varnish is used to produce a prepreg by a wet process.
• NE is an aromatic test such as BTDE.
• Reactivity with diamins such as DDM is higher than that of dicarboxylic diesters, so that the reaction between NE and DDM proceeds preferentially during storage of varnish, producing low-molecular-weight bisnadiimide (BI).
• An object of the present invention is to provide an R-type polyimide varnish excellent in storage stability without the above-mentioned disadvantages, a terminal sealant used for preparing such a varnish, and an impregnated with such a varnish.
• Textile material An object of the present invention is to provide an intermediate material for a reinforced composite material.
• the present invention provides, in one aspect, a terminal blocking agent for polyimide represented by the general formula [1]. [1]
• R 3 and R 4 are independently selected from the group consisting of hydrogen and an alkyl group having 1 to 4 carbon atoms.
• a terminal blocking agent represented by the above formula [1] a tetraalkyl carboxylic acid dialkyl ester represented by the general formula [2]
• a diamine represented by the general formula [3] The present invention provides a PMR-type polyimide varnish comprising:
• R is a direct bond, CH z, 0, C0, S0 z, S or C (CH 3) Z,
• X is an alkyl group having 1 to 4 carbon atoms
• R z is a direct bond, CH 2, 0, C0, S0 2, S or C (CH 3) 2.
• the present invention provides an intermediate material for a fiber-reinforced composite material, in which the above-mentioned polyimid varnish is soaked in a reinforcing arrowhead.
• BEST MODE FOR CARRYING OUT THE INVENTION The compound of the present invention represented by the general formula [1] is used as a terminal blocking agent for polyimide.
• Polyimide is not limited to the PMR type, but is particularly useful for the PMR type polyimide as described below.
• NE nadic acid monoalkyl ester
• BTDE which is the main constituent of PMR-type polyimide
• NE is an alicyclic dicarboxylic acid monoalkyl ester
• aromatic tetracarboxylic acid dialkyl ester is an aromatic tetracarboxylic acid dialkyl ester.
• the reaction between the monoalkyl aromatic dicarboxylate and the aromatic amine starts at 100 cc or more, whereas the monoalkyl alicyclic dicarboxylate has high reactivity, so that the aromatic amine can be used even at room temperature. Reaction proceeds easily. Therefore, in order to solve this problem, it is necessary to lower the reactivity of the end capping agent and make it more reactive than other monomers constituting the main chain of the PMR-type polyimide.
• a najimid-type end capping agent having an aromatic amine in the reaction part exhibits controlled reactivity and satisfies the above requirements. That is, by introducing an aromatic amine instead of using a highly reactive alicyclic dicarboxylic acid monoester as a reactive part of the end capping agent, the same effect as other monomers can be obtained. It became possible to provide reactivity.
• ⁇ examples include 1-amino-4—nadimidobenzene, 111-amino-2—methyl-14nadiumimidbenzene and 1-aminodibenzene — Amino 2 and 6 — Dimethyl 4 — Vietnamesemidbenzen.
• the terminal blocking agent according to the present invention is a novel compound and can be synthesized by the following method.
• nadic anhydride is reacted with ditroyurin or an alkyl-substituted product thereof in an acetamide solution, and nadimidonitrobenzene is used as an intermediate.
• Synthesized and then reduced using stannous chloride The method shown in the following reaction formula (1)
• the second method is to synthesize a maleimide nitrate benzene compound, then add cyclopentadiene to the compound, and finally reduce the nitro group, as shown in the reaction formula (2). It is.
• the PMR-type polyimid varnish of the present invention comprises a terminal blocking agent represented by the general formula (1), a dialkyl tetracarbonate represented by the general formula (2), and an optional component represented by the general formula (3). It contains a diamine and an organic solvent as an optional ingredient.
• dialkyl tetracarboxylate represented by the general formula [2] include 3, 3 ', 4, and 4' benzophenenot Dimethyl lacarboxylate and 3,3 ′, 4,4′-benzophenone tetracarboxylic acid getyl ester.
• diamine represented by the general formula [3] examples include 44'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, and 4,4'dia Minodiphenyl methane, 3,3'-diaminodiphenylphenyl, 4,4'-diaminodiphenylsulfone and 3,3'-diaminodiphenylphenyl sulfone.
• the PMR-type polyimide varnish comprises a terminal blocking agent represented by the general formula [1], a tetraalkyl dialkyl carbonate represented by the general formula [2], and a diamine represented by the general formula [3].
• the organic solvent include alcohols represented by the general formula R'OH (where R 'is an alkyl group having 1 to 4 carbon atoms) (for example, methanol and ethanol) and dimethylforma. A mid or the like is used.
• the amount of solvent is from 0 to 20% by weight based on the amount of polyimide varnish.
• the organic solvent is used. Agents need not be used.
• Polyimide oligo obtained from the above-mentioned PMR-type polyimid varnish is represented by the following formula, where n is the number of repeating units in the form of oligomers.
• Terminal blocking agent tetraalkyl dicarboxylate: diamine
• n + 1) n
• an arbitrary average molecular weight can be obtained.
• the chemical structure of diamine-type monomers and tetraalkyl carboxylic acid dialkylester-type monomers is calculated as the average molecular weight when they are converted into monomers. By doing so, resins with different heat resistance, physical properties, moldability, etc. can be obtained.
• the average molecular weight of the resin obtained from the PMR type polyimid varnish increases as the molecular weight increases, the mechanical properties improve, but the heat resistance and moldability decrease.
• the average number of repeating units n when it is oligomerized is preferably in the range of 0 to 10, and especially when n is in the range of 0, 4 to 2, a balance can be obtained in terms of heat resistance, moldability, and physical properties. It is suitable as a PMR type poly varnish.
• the PMR-type polyimid varnish of the present invention may have its viscosity and viscosity adjusted as necessary, and may have the toughness, elastic modulus, elongation and other mechanical properties of a cured product obtained from this varnish.
• thermoplastic polymers such as polyethersulfone, polysulfone, thermoplastic polyimide, ebonashi resin, and diarylbisfuninol A and other reactive diluents are used. Appropriate amounts can be added. Usually, the amount of these additional components is Less than 40% by weight based on the total weight of polyamide varnish excluding organic solvent.
• the PMR-type polyimide varnish according to the present invention when impregnated into reinforced textiles, has excellent tack and drape properties of the pre-bleder, has excellent moldability, and has a resin obtained by curing it. Excellent heat resistance and mechanical properties make it an excellent matrix resin for fiber-reinforced composite materials. In addition, it is also suitable as an adhesive or a molding material.
• the reinforcing fibers include carbon fiber, graphite fiber, aramide fiber, silicon carbide fiber, alumina fiber, and borosilicate fiber. Fibers and glass fibers are used. Among these, high-strength carbon fibers are particularly preferred. It is also possible to mix and use different types of fibers.
• the form of textiles can be any form, such as long fibers, woven fabrics, knitted fabrics, mats, and cut fibers.
• the ratio of the reinforcing fiber and the PMR type polyimide varnish in the fiber-reinforced composite material is preferably 30 to 80% by weight of the former and 70 to 20% by weight (excluding the organic solvent) of the latter. .
• a prepreg was prepared by a hot melt method using a varnish stored at 20'c for 60 days and carbon fibers ("Tray power" T400 manufactured by Toray Industries, Inc.). The resin content of the obtained prepreg was 39.6%.
• the resulting pre-preda was cut to a length of 30 cm and a width of 20 cm, laminated, pressurized in an autoclave with 160 and 14 ciU, and then heated to 290 After holding for 2 hours and cooling to room temperature, the molded article was taken out of the autoclave. The obtained molded article was after-cured with 316 for 6 hours to obtain a molded article.
• the carbon fiber volume content in the obtained molded product was 60.2%, and the glass transition temperature measured by the DSC method was 332, indicating that it had good heat resistance.
• a test piece was cut out from the obtained molded article according to ASTM and D-790, and the bending characteristics were measured.
• the bending strength was 190 kg / « 2
• the bending elastic modulus was 13.8 t / h ⁇ 2 . It had mechanical properties.
• the terminal blocking agent represented by the general formula [1] of the present invention is useful as a polyimide terminal blocking agent to be incorporated into a PMR type polyimide varnish.
• This PMR type polyimide varnish has the property of having good storage stability, and is particularly useful as a matrix resin having high mechanical properties to be blended with the fiber reinforced composite material.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
• Reinforced Plastic Materials (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)
• Macromonomer-Based Addition Polymer (AREA)
• Indole Compounds (AREA)

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Citations (3)

• 1987
  • 1987-01-13 JP JP403787A patent/JPS63172736A/ja active Granted
• 1988
  • 1988-01-13 WO PCT/JP1988/000027 patent/WO1993013156A1/ja not_active Ceased

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