Polyaminobisimide resins

Abstract: A polyaminobisimide resin is disclosed comprising an unsaturated bisimide component and a diamine component which is a 1,3-bis or 1,4-bis(2-p-anilinopropylidene) benzene compound. The resin may be used to form laminates and shaped articles, and these exhibit improved ply separation strength and water absorption.

Description: The present invention relates to polyaminobisimide resins, more particularly, to resins that use particular diamines that are capable of improving the physical properties of the cured products of the resins. Polyaminobisimide resins are resins having high heat stability which are formed of unsaturated bisimides and diamines. Industrially, polyaminobisimide resins are commonly produced by using as an unsaturated bisimide the bismaleimide composed of maleic anhydride and methylenedianiline (MDA; also referred to as methylenebisaniline or 4,4'-diaminodiphenylmethane), and methylenedianiline as a diamine. After being cured to provide a three-dimensional structure, such resins exhibit superior heat stability by resisting thermal distortion. However, they incur such defects as brittleness and insufficient bonding strength which are evidenced by insufficient tensile strength and impact strength, and these defects are believed to originate from the excessive rigidity of the resins. The physical properties that are required of the cured products of resin compositions to be used in laminates include not only good mechanical properties and high heat stability but also improved ply separation strength and copper foil bonding strength, as well as reduced water absorption. Reduction in water absorption is a particularly important objective since a smaller amount of water absorption will contribute higher reliability to electrical characteristics. EP-A-0107897 relates to polyamino-bis-amide resins produced by the reaction of an unsaturated bis-imide and a diamine comprising four aromatic rings. EP-A-0163518 discloses thermoplastic polymers formed by the reaction of aromatic or aliphatic dianhydrides and/or acid anhydrides with diamines which comprise three aromatic rings. US-A-4654407 discloses novel bismaleimides, produced by the condensation of maleic anhydride with aromatic diamines, which may be employed in prepregable resin compositions. An object of the present invention is to provide a polyaminobisimide resin composed of an unsaturated bisimide and a diamine which employs 1,3-bis and/or 1,4-bis(2-p-anilinopropylidene) benzene as a diamine component so that it will, when cured and used in a laminate, exhibit improved ply separation strength and water absorption. The present invention provides a polyaminobisimide resin comprising the product of the reaction between an unsaturated bisimide component and a diamine component, wherein the unsaturated bisimide component is maleic acid N,N'-ethylene-bis-imide, maleic acid N,N'-hexamethylene-bis-imide, maleic acid N,N'metaphenylene-bis-imide, maleic acid N,N'-paraphenylene-bis-imide, maleic acid N,N'-4,4'-diphenylmethane-bis-imide, maleic acid N,N'-4,4'-diphenylether-bis-imide, maleic acid N,N'-4,4'-diphenylsulfone-bis-imide, maleic acid N,N'-4,4'-dicyclohexylmethane-bis-imide, maleic acid N,N'-α, α'-4,4'-dimethylenecyclohexane-bis-imide, maleic acid N,N'-metaxylylene-bis-imide, or maleic acid N,N'-diphenylcyclohexane-bis-imide and the diamine component is a 1,3-bis(2-p-anilino-propylidene) benzene having the following formula (I) or a 1,4-bis(2-p-anilinopropylidene) benzene having the following formula (II) where each R, which may be the same or different in (I) and (II), is a halogen or an alkyl group, and n is from 0 to 4. The molar ratio of the unsaturated bisimide defined above to the diamine of formula (I) and/or formula (II) ranges generally from 1.2:1 to 50:1, preferably from 1.3:1 to 5:1. This condition should be satisfied in order to provide a cured product having superior heat stability. The polyaminobisimide resin of the present invention, which contains the unsaturated bisimide component and diamine component described above, may be copolymerized with epoxy resins, phenolic resins, aniline resins, polychloroethylene resins, or may be blended therewith to form resin compositions subject to the condition that the incorporation of these additional components should not alter the basic properties of the polyaminobisimide resin. This resin may also be formulated as a resin composition containing reactive diluents such as vinyl monomers, reaction accelerators such as organic peroxides, or some other suitable additives. Also inorganic fillers may be used which include fused silica (amorphous), crystalline silica, alumina and a mixture thereof. These fillers may be used as a blend thereof with another filler such as titanium dioxide, mica, calcium carbonate, talc, aluminum hydroxide, cordierite, boron nitride, silicon carbide, and glass fibres. An advantageous process for producing the novel resin of the present invention may proceed as follows: a diamine of formula (I) and/or formula (II), an unsaturated bisimide as defined above and any other necessary components are mixed, and the mixture is heated at a suitable temperature in the range of 100-250°C for a period of from 5 minutes to 5 hours so as to make a prepolymer. If desired, the prepolymer may be prepared in a polar solvent such as dimethylformamide or N-methylpyrrolidone. Alternatively, suspensions in other solvents may be employed. The resin of the present invention may also be prepared in the form of a block by heating a kneaded mixture of the diamine and unsaturated bisimide. The resulting resin may be used as a solution or suspension. It may be shaped by thermal casting or it may be used as a powder. The resin of the present invention is preferably cured by heating at a temperature of from about 180 to about 250°C, optionally under pressure. The resulting cured product of the resin will neither melt nor dissolve. It is highly resistant to thermal distortion, has good dielectric properties, and is stable against chemicals. This resin is particularly adapted for the manufacture of laminates and may be processed into prepregs or other useful elements together with fibrous or fine particulate fillers. Alternatively, the resin may be formed into shaped articles either on its own or together with other resins. The following examples are provided for the purpose of further illustrating the present invention but are in no way to be taken as limiting. In the examples and comparative examples that follow, prepolymers were prepared, dissolved in solvents to make varnish; fibers were then impregnated with the varnish and dried to make prepregs; the prepregs were sandwiched between copper foils to make laminates. The physical properties of the laminates were evaluated under the conditions described below. The results are shown in Table 1. Evaluation Tests (1) Copper foil separation strength Copper foils were peeled from the laminate to determine its strength under the conditions described in JIS C6481. (2) Ply separation strength Prepreg plies were delaminated to determine the strength of the laminate under the same conditions as those employed in the measurement of copper foil separation strength. (3) Solder resistance The laminate was in a solder bath at 300°C for 5 minutes and the appearance of the laminate was visually inspected. (4) Water absorption Water absorption measurements were conducted under the following conditions. D-24/23: Immersed in distilled water at 23°C for 24 h. D-1/100: Immersed in boiling distilled water at 100°C for 1 h. EXAMPLE 1 A 500-ml flask was charged with 55.5g of 1,3-bis(2-p-anilino-propylidene) benzene (m.p.=115°C) and the charge was melted by immersing the flask in an oil bath at 150°C. To the molten charge, 144.5g of N,N'-4,4'-diphenylmethanebismaleimide (molar ratio, 2.5) was added and the two components were mixed for reaction for 20 minutes. The reaction mixture was transferred into a vat, which was placed in an air oven at 170°C and heated for an additional 12 minutes to make a prepolymer. The prepolymer was dissolved in N-methylpyrrolidone to make varnish. A glass cloth was impregnated with the varnish and dried at 160°C for 12 minutes to prepare a prepreg. Nine plies of this prepreg were superposed, sandwiched between copper foils, and pressed at 981 kPa (10 kp/cm²) with heating at 180°C for 60 minutes so as to prepare a copper-clad laminate. The laminate was subsequently post-cured at 200°C for 24 hours. COMPARATIVE EXAMPLE 1 A laminate was prepared as in Example 1 (molar ratio of unsaturated bisimide component to diamine component =2.5:1) except that 1,3-bis(2-p-anilinopropylidene) benzene was replaced by methylenedianiline. EXAMPLE 2 A 500-ml flask was charged with 64.9g of 1,3-bis(2-p-anilinopropylidene) benzene and the charge was melted by immersing the flask in an oil bath at 150°C. To the molten charge, 135.1g of N,N'-4,4'-diphenylmethanebismaleimide (molar ratio, 2.0) was added and the two components were mixed for reaction for 20 minutes. The reaction mixture was transferred into a vat, which was placed in an air oven at 170°C and heated for 15 minutes to make a prepolymer. The prepolymer was dissolved in N-methylpyrrolidone to make varnish. A glass cloth was impregnated with the varnish and dried at 160°C for 12 minutes to prepare a prepreg. Nine plies of this prepreg were superposed, sandwiched between copper foils, and pressed at 981 kPa (10 kp/cm²) with heating at 180°C for 60 minutes so as to prepare a copper-clad laminate. The laminate was subsequently post-cured at 200°C for 24 hours. COMPARATIVE EXAMPLE 2 A laminate was prepare as in Example 2 (molar ratio of unsaturated bisimide component to diamine component=2.0:1) except that 1,3-bis(2-p-anilinopropylidene) benzene was replaced by methylenedianiline. Run No. Copper foil peel strength (kgf/cm) Interlaminar peel strength (kgf/cm) Solder resistance (300°C X 5min) Water absorption (%) D-24/23 D-1/100 Example 1 1.9 1.3 0.K 0.14 0.14 Comparative Example 1 1.2 0.9 0.K 0.26 0.27 Example 2 2.0 1.7 0.K 0.14 0.13 Comparative Example 2 1.4 1.1 0.K 0.25 0.26 Example 3 1.8 1.3 0.K 0.14 0.14 The resin of the present invention has the advantage that it provides a cured product having improved ply separation strength and water absorption characteristics over the polyaminobismaleimide resins that are currently available on the market. Therefore, the polyaminobisimide resin of the present invention has the potential to find increasing use in the following fields of high technology: (1) resins for use in the fabrication of multi-layered laminates in the CPU of a large-scale computer; (2) shaped articles for use as gears and other sliding members; and (3) a variety of heat-resistant shaped parts. EXAMPLE 3 A 500 ml flask was charged with 27.8g of 1,3-bis(2-p-anilinopropylidene) benzene and 27.8g of 1,4-bis (2-p-anilinopropylidene) benzene. The charge was melted by immersing the flask in an oil bath at 150°C. To the molten charge 144.5g of N,N'-4,4'-diphenylmethane bismaleimide (molar ratio 2.5 ) was added and the three components were mixed for reaction for 20 minutes. The reaction mixture was transferred into a vat, which was placed in an air oven at 170°C and heated for 15 minutes to prepare a prepolymer. The prepolyer was dissolved in N-methylpyrrolidone to make varnish. A glass cloth was impregnated with the varnish and dried at 160°C for 12 minutes to prepare a prepreg. Nine plies of this prepreg were superposed, sandwiched between copper foils, and pressed at 981 kPa (10 kp/cm²) while heating at 180°C for 60 minutes so as to prepare a copper-clad laminate. The laminate was then post-cured at 200°C for 24 hours. The properties of the resultant laminate are shown in Table 1.

Claims: Claims for the following Contracting States : AT, BE, FR, DE, IT, LU, NL, SE, CH, GB A polyaminobisimide resin comprising the product of the reaction between an unsaturated bisimide component and a diamine component, characterised in that the unsaturated bisimide component is maleic acid N,N'-ethylene-bis-imide, maleic acid N,N'-hexamethylene-bisimide, maleic acid N,N'metaphenylene-bis-imide, maleic acid N,N'-paraphenylene-bis-imide, maleic acid N,N'-4,4'-diphenylmethane-bis-imide, maleic acid N,N'-4,4'-diphenylether-bis-imide, maleic acid N,N'-4,4'-diphenylsulfone-bis-imide, maleic acid N,N'-4,4'-dicyclohexylmethane-bis-imide, maleic acid N,N'-α, α'-4,4'-dimethylenecyclohexane-bis-imide, maleic acid N,N'-metaxylylene-bis-imide, or maleic acid N,N'-diphenyl-cyclohexane-bis-imide and the diamine component is a 1,3-bis(2-p-anilino-propylidene) benzene having the following formula (I) or a 1,4-bis(2-p-anilinopropylidene) benzene having the following formula (II) where each R, which may be the same or different in (I) and (II), is a halogen or an alkyl group, and n is from 0 to 4. A resin according to claim wherein the molar ratio of the unsaturated bisimide to the diamine or formula (I) or formula (II) is from 1.2:1 to 50:1. A resin according to claim 1 or 2 wherein the molar ratio of the unsaturated bisimide to the diamine of formula (I) or formula (II) is from 1.3:1 to 5:1. A resin composition formed by blending or copolymerizing a polyaminobisimide resin as claimed in any one of the preceding claims with an epoxy, phenolic, aniline or polychloroethylene resin. A resin composition according to claim 4 which includes reactive diluents such as vinyl monomers, reaction accelerators such as organic peroxides or inorganic fillers such as silica, alumina, titanium dioxide, mica, calcium carbonate, talc, aluminium hydroxide, cordierite, boron nitride, silicon carbide or glass fibres. A process for producing a resin as claimed in any one of claims 1 to 3 which comprises mixing the diamine of formula (I) or (II) with the unsaturated bisimide, optionally in the presence of a solvent, heating the mixture to 100° to 250°C for a period of from 5 minutes to 5 hours to make a prepolymer and curing the prepolymer at a temperature of from 180 to 250°C, optionally under pressure, to form the resin. A laminate, prepreg or shaped article manufactured from a resin as claimed in any one of claims 1 to 3 or a resin composition as claimed in claim 4 or 5. Claims for the following Contracting State : ES A process for producing a polyaminobisimide resin, the process comprising mixing a diamine of the following formula (I) or (II) wherein each R, which may be the same or different in (I) and (II), is a halogen or an alkyl group, and n is from 0 to 4, with an unsaturated bisimide which is maleic acid N,N'-ethylene-bis-imide, maleic acid N,N'-hexamethylene-bis-imide, maleic acid N,N'metaphenylene-bis-imide, maleic acid N,N'-paraphenylene-bis-imide, maleic acid N,N'-4,4'-diphenylmethane-bis-imide, maleic acid N,N'-4,4'-diphenylether-bis-imide, maleic acid N,N'-4,4'-diphenylsulfone-bis-imide, maleic acid N,N'-4,4'-dicyclohexylmethane-bis-imide, maleic acid N,N'-α, α'-4,4'-dimethylenecyclohexane-bis-imide, maleic acid N,N'-metaxylylene-bis-imide, or maleic acid N,N'-diphenylcyclohexane-bis-imide; optionally in the presence of a solvent, heating the mixture to 100° to 250°C for a period of from 5 minutes to 5 hours to make a prepolymer and curing the prepolymer at a temperature of from 180° to 250°C, optionally under pressure, to form the resin. A process according to claim 1 wherein the molar ratio of the unsaturated bisimide to the diamine of formula (I) or formula (II) is from 1.2:1 to 50:1. A process according to claim 1 or 2 wherein the molar ratio of the unsaturated bisimide to the diamine of formula (I) or formula (II) is from 1.3:1 to 5:1. A process according to any one of the preceding claims which further comprises blending or copolymerizing the resulting polyaminobisimide resin with an epoxy, phenolic, aniline or polychloroethylene resin to form a resin composition. A process according to claim 4 which comprises incorporating reactive diluents such as vinyl monomers, reaction accelerators such as organic peroxides or inorganic fillers such as silica, alumina, titanium dioxide, mica, calcium carbonate, talc, aluminium hydroxide, cordierite, boron nitride, silicon carbide or glass fibres into the resin composition. A process according to any one of the preceding claims which further comprises forming the resin or resin composition into a laminate, prepreg or shaped article.

Inventors: KAN KOJIRO C O MITSUI PETROCHE, KANEKO ISAO C O MITSUI PETROCH, KAN, KOJIRO C/O MITSUI PETROCHEMICAL, KANEKO, ISAO C/O MITSUI PETROCHEMICAL
Applicants: MITSUI PETROCHEMICAL IND, MITSUI PETROCHEMICAL INDUSTRIES, LTD.
Application year: 1988
Main classification: C08G73
IPC codes: C08G73