JP2009203252A - Bulk molding compound and its molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a BMC exhibiting excellent preservation stability that is obtained by impregnating a reinforcing fiber material with a polyimide resin without using any solvent, and a molded article manufactured from the BMC and its manufacturing method. <P>SOLUTION: The BMC material comprises the reinforcing fiber material impregnated with the matrix resin, where the matrix resin is a thermosetting polyimide resin having a melting point. The thermosetting polyimide resin having a melting point is a reaction product of at least one aromatic tetracarboxylic acid dianhydride, at least one aromatic diamine and at least one terminating agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bulk molding compound (hereinafter abbreviated as BMC) and a molded article excellent in heat resistance and dimensional stability obtained by molding the BMC. Specifically, the present invention relates to a BMC made of a thermosetting polyimide resin having a melting point and a reinforcing fiber material.

  BMC is a molding material in which a reinforcing fiber material such as carbon fiber or glass fiber and a thermosetting resin are mixed and impregnated. Usually, this BMC can obtain a target molded product by a molding method using heating / pressurizing means such as press molding, transfer molding, and injection molding. Molded articles obtained using these BMCs are excellent in durability, heat resistance, mechanical properties, non-combustibility, and the like, and are used in automobiles, aerospace, electrical / electronic devices, semiconductor manufacturing equipment, artificial marble, It is also attracting attention in general industrial applications such as building materials, and its demand is increasing year by year.

  For these BMCs, a reinforcing fiber material and a matrix resin are selected according to the use and required characteristics of a molded product produced using the BMC. As the matrix resin, an epoxy resin, an unsaturated polyester resin, a phenol resin, Vinyl ester resins, polyamideimide resins, polyimide resins, and the like are used. In addition, as the reinforcing fiber material, carbon fiber, glass fiber, polyamideimide fiber, and other plastic fibers are generally used.

  By the way, in recent years, BMC has been used for various purposes, and the characteristics required for BMC are various. The required characteristics are (1) weight reduction, (2) dimensional stability, (3 ) Mechanical characteristics, (4) heat resistance, and (5) chemical resistance. However, it is becoming difficult to satisfy the required characteristics (1) to (5) above with a molded product using a conventional BMC.

  In order to solve such a problem, development of BMC using a polyimide resin as a matrix resin is underway. In other words, in addition to its high heat resistance, polyimide resin is superior in mechanical properties and dimensional stability, and also has nonflammability and electrical insulation properties, so it can be used in a wide range of electrical and electronic equipment, space and aircraft equipment, etc. This is because it is used in the field and has an excellent track record for many years.

  In the technique using these polyimide resins as a matrix resin for BMC, in Patent Document 1, reinforcing fibers are dispersed in a linear aromatic polyimide resin, and the weight ratio of the linear aromatic polyimide resin to the reinforcing fibers is 95: A fiber reinforced polyimide that is 5 to 35:65 is disclosed. In Patent Document 2, a tetracarboxylic acid dimethyl ester compound, a diamine compound, exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride and / or exo-3,6-epoxy-1, An addition-type polyimide resin raw material composition comprising a 2,3,6-tetrahydrophthalic acid monoester compound and a prepolymer-containing composition thereof are disclosed.

  Next, in Patent Document 3, an imide oligomer solution in which an addition-type imide oligomer is dissolved in an organic solvent in a weight ratio of 20% or more is impregnated into a reinforcing fiber or a fiber fabric by a liquid molding method, and the organic solvent is volatilized. A method of forming a composite material by adding an imide oligomer to the imide oligomer after the reaction is disclosed. Furthermore, in patent document 4, the polyimide resin composition which makes an aromatic bisimide compound contain a polyimide resin, and apply | coat these aromatic bisimide compounds on the surface of carbon fiber, and this carbon fiber is made to contain with a polyimide resin. A carbon fiber reinforced polyimide resin composition is disclosed.

However, in the BMC manufacturing methods described in the above-mentioned patent documents, a method of impregnating a reinforced fiber material with a polyimide resin is a method in which a reinforced fiber material is introduced into a liquid, solution, gel-like polyimide resin or polyimide precursor containing a solvent. However, there is a problem that the storage stability of BMC is poor. Further, when a molded product is manufactured using the BMC manufactured by such a method, a void is generated in the molded product due to generation of condensed water or the like due to evaporation of the solvent or imide conversion in the thermoforming process. There were problems such as deterioration of characteristics or poor flow of polyimide resin.
JP 2000-239524 A JP 2003-292619 A JP 2006-117788 A JP 2001-131147 A

  The present invention has been made in view of the above-described conventional problems, and is produced from a BMC having excellent storage stability obtained by impregnating a reinforced fiber material with a polyimide resin without using any solvent, and the BMC. An object of the present invention is to provide a molded article and a method for producing the same.

  As a result of continuing research and development on thermosetting polyimide resin having a melting point and conditions and methods for impregnating the polyimide resin into the reinforcing fiber material, the inventors have melted the polyimide resin into the reinforcing fiber material. Thus, by mixing and impregnating, it was found that the polyimide resin can be smoothly penetrated and impregnated inside the strand of the reinforcing fiber material, and the present invention has been completed.

  That is, a first invention according to the present application is a BMC obtained by impregnating a reinforcing fiber material with a matrix resin, wherein the matrix resin is a thermosetting polyimide resin having a melting point. Next, a second invention according to the present application is the invention described in claim 1, wherein the thermosetting polyimide resin having the melting point is at least one aromatic tetracarboxylic dianhydride, at least one aromatic. A reaction product of a diamine and at least one end-stopper.

  Next, a third invention according to the present application is the invention described in claim 2, wherein the thermosetting polyimide resin having the melting point is a first aromatic tetracarboxylic dianhydride, a second aromatic. A reaction product of tetracarboxylic dianhydride, at least one aromatic diamine and at least one end-stopper, wherein the first aromatic tetracarboxylic dianhydride comprises the first and second The second aromatic tetracarboxylic dianhydride is present in an amount of about 5 to 40% by weight relative to the total weight of the aromatic tetracarboxylic dianhydride, the second aromatic tetracarboxylic dianhydride being the first and second aromatic tetra It is BMC which exists in the quantity of 60 to 95 weight% with respect to the total weight of carboxylic dianhydride.

  A fourth invention according to the present application is the invention described in claims 2 and 3, wherein the aromatic tetracarboxylic dianhydride is a BMC having two or more aromatic rings in its chemical structure. is there. The aromatic tetracarboxylic dianhydride considered suitable for use in the preparation of the thermosetting polyimide resin having a melting point of the present invention has the following formula (I)

Or the following general formula (II)

(However, Z is -CO -, - O -, - or a direct bond represents a - SO ₂₎ is generally a tetracarboxylic acid dianhydride having two or more aromatic rings in the chemical structure represented by.

  The aromatic tetracarboxylic dianhydride having the structure (I) is 1,2,4,5-benzenetetracarboxylic dianhydride (also referred to as pyromellitic dianhydride or PMDA), and the structure (II) Examples of the aromatic tetracarboxylic dianhydride having the following are 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 4,4′-oxydiphthalic anhydride (OPDA), 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA) and the like are preferable.

  In preparing the thermosetting polyimide resin having the melting point of the present invention, one or more aromatic tetracarboxylic dianhydrides are used. When two aromatic tetracarboxylic dianhydrides are used, the first aromatic tetracarboxylic dianhydride (eg, BTDA) is 5% by weight based on the total weight of the aromatic tetracarboxylic dianhydride. Preferably present in an amount of 40% by weight or less (more preferably 10% by weight 25% by weight, most preferably 20% by weight 25% by weight) and a second aromatic tetracarboxylic dianhydride (eg BPDA) is 60% by weight or more and 95% by weight or less (more preferably 75% by weight or more and 90% by weight or less, most preferably 75% by weight or less 80% by weight) based on the total weight of the aromatic tetracarboxylic dianhydride. Is preferably present in an amount of.

  Next, a fifth invention according to the present application is the invention described in claim 2, wherein the thermosetting polyimide resin having the melting point is at least one aromatic tetracarboxylic dianhydride and two aromatic diamines. And at least one of the two aromatic diamines has one or more oxygen bonds in its chemical structure, and the two aromatics. BMC present in an amount of at least 50% by weight relative to the total weight of the group diamine.

  Next, a sixth invention according to the present application is the BMC according to the invention described in claim 5, wherein the aromatic diamine has at least one ether bond in its chemical structure. Aromatic diamines considered suitable for use in the present invention are m-phenylenediamine (m-PDA), 3,4'-oxydianiline (3,4'-ODA), 4,4'-oxy. Dianiline, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), bis [4- (3-aminophenoxy) phenyl] sulfone (BAPS-M), 1,3-bis ( Aromatic diamines such as 3-aminophenoxy) benzene (APB) and 1,3-bis (4-aminophenoxy) benzene (TPE-R).

  In preparing the thermosetting polyimide resin having the melting point of the present invention, one or more aromatic diamines are used. When two types of aromatic diamines are used, at least one aromatic diamine has one or more oxygen bonds, and the aromatic diamine is at least 50% by weight or more based on the total weight of the aromatic diamine. Is preferably present in an amount of.

  Next, according to a seventh aspect of the present invention, in the invention described in any one of the second, third, and fifth aspects, the terminal terminator is an unsaturated carbocyclic monomer acid anhydride, and the unsaturated carbon The cyclic monomeric acid anhydride is a BMC that forms an oligomer having a melting point of less than 250 ° C. and a melt viscosity at 200 ° C. of 500 cps or more and 50,000 cps or less.

  A suitable terminator for use in preparing the thermosetting polyimide resin having a melting point of the present invention forms an oligomer having a melting point of less than about 250 ° C. and a melt viscosity at 200 ° C. of 500 cps to 50,000 cps. Unsaturated carbocyclic monomer acid anhydride. Such monomeric acid anhydrides include nadic acid anhydride (5-norbornene-2,3-dicarboxylic acid anhydride: HA), alkyl derivatives of maleic acid anhydride, that is, methylmaleic acid anhydride (citraconic acid anhydride). : CA), itaconic anhydride (IA), dimethylmaleic anhydride, 2-octen-1-ylsuccinic anhydride and the like.

  Next, according to an eighth aspect of the present invention, in the invention described in any one of the first to seventh aspects, the melting point of the thermosetting polyimide resin having the melting point is less than 200 degrees C, and 200 degrees A BMC having a melt viscosity at C of 50,000 cps or less. The thermosetting polyimide resin having a melting point of the present invention has a melting point of 250 ° C. or less (preferably 225 ° C. or less), a low melt viscosity at 200 ° C., and 50,000 cps or less (preferably 1,000 cps). Above 25,000 cps). Therefore, these resins can be processed at a relatively low processing temperature of the polyimide resin. Furthermore, the processing window at 200 ° C. (the time for the lowest melt viscosity) of the thermosetting polyimide resin having the melting point of the present invention is at least about 60 minutes, and the curing temperature is 300 ° C. or higher and 375 ° C. or lower, preferably Is 320 degrees C or more and 350 degrees C or less. The theoretical average molecular weight of the thermosetting polyimide resin having a melting point of the present invention is 4,000 or less, preferably 2,000 or more and 3,000 or less.

  The synthesis of the thermosetting polyimide resin having a melting point of the present invention is performed by first preparing an amic acid solution and then preparing an imide powder.

The amic acid solution is, for example,
(1) charging at least one aromatic tetracarboxylic dianhydride (eg BPDA) and at least one aromatic diamine (eg BAPP) into separate reaction vessels;
(2) A predetermined solvent (for example, N-methyl-2-pyrrolidone (NMP)) is added to each reaction vessel, and a slurry or solution of aromatic tetracarboxylic dianhydride is added to one vessel, and a fragrance is added to the other vessel. Producing a slurry or solution of a genus diamine,
(3) The slurry or solution in each reaction vessel is heated to a temperature of 50 ° C. to 120 ° C. to dissolve the aromatic tetracarboxylic dianhydride and the aromatic diamine,
(4) Cool the solution in each reaction vessel to ambient temperature or room temperature,
(5) The aromatic tetracarboxylic dianhydride solution is gradually added to the diamine solution over 10 to 60 minutes,
(6) A terminal terminator (for example, citraconic anhydride (CA) dissolved in NMP) is added to the reaction vessel,
(7) Prepared by stirring the solution for 15-120 minutes. At this time, the molar ratio of the aromatic tetracarboxylic dianhydride, the aromatic diamine, and the terminal terminator was about 1.0 / 1.95 / 2.10 to 1.0 / 2.1 / 2.0. Adjust so that

  By the way, when the aromatic tetracarboxylic dianhydride solution is gradually added to the aromatic diamine solution while controlling the reaction temperature in the above-described step of preparing the amic acid solution, the molecular weight of the resulting resin is reduced. The melting point and melt viscosity of the resulting resin are preferably reduced.

  Suitable solvents for use in the method for producing the polyimide resin of the present invention include amide solvents such as NMP, N, N-dimethylacetamide, N, N-dimethylformamide, N-methylcaprolactam, etc. Among these, NMP and N, N-dimethylacetamide are preferable.

  In order to produce a polyimide resin having a melting point of 250 ° C. or less and a melt viscosity at 200 ° C. of 50,000 centipoise or less, an aromatic tetracarboxylic dianhydride, an aromatic diamine, and a terminal stopper are used. It is desirable that the molar ratio be such that a low molecular weight prepolymer having at least one end-stopping radical and suitable for chain extension and crosslinking is produced by stirring the solution. Typically, the theoretical average molecular weight of the prepolymer is, for example, 4,000 grams per mole (that is, 4,000 g / mol) or less, preferably 2000 g / mol or more and 3000 g / mol or less.

  In addition, the molar ratio of aromatic tetracarboxylic dianhydride, aromatic diamine, and terminal stopper is aromatic tetracarboxylic dianhydride / aromatic diamine / terminal stopper = 1.0 / 2.0 / 2. .01 is preferable, and aromatic tetracarboxylic dianhydride / aromatic diamine / terminal stopper = n / n + 1/2 is more preferable.

  The synthesis of the imide powder according to the present invention requires either chemical imidization or thermal imidization. In a preferred embodiment, the imide powder is prepared by chemical imidization, where a strongly acidic material is used to promote ring closure and an azeotropic agent is used to remove azeotropic water. Furthermore, in a more preferred embodiment, a strongly acidic material such as methanesulfonic acid is used as a catalyst and the azeotropic water is removed using a tertiary amine cosolvent such as toluene.

More specifically, for example, imide powder is
(1) Both 20% by weight to 40% by weight (preferably 25% by weight to 35% by weight) of an amic acid solution and 60% by weight to 80% by weight (preferably 65% by weight to 75% by weight) Put a boiling agent (eg toluene) into the reaction vessel,
(2) 0.05 wt% or more and 0.5 wt% or less (preferably 0.1 wt% or more and 0.2 wt% or less) of a strongly acidic catalyst (for example, methanesulfonic acid) is charged into a reaction vessel to form a mixture. And
(3) The mixture in the reaction vessel is heated for 2 to 6 hours until the temperature reaches 100 ° C to 130 ° C (preferably 120 ° C to 125 ° C),
(4) Cool the mixture to ambient or room temperature,
(5) removing the azeotropic agent from the reaction vessel;
(6) Prepared by isolating and recovering solids or imide powder from residual solution in reaction vessel.

  By the way, when the strong acid substance and the azeotropic agent are used in the above amounts in the preparation step of the imide powder, the ring closing temperature can be effectively controlled. More specifically, the strongly acidic material produces more water and the azeotropic agent reduces the reflux point of the system.

  Next, a ninth invention according to the present application is the BMC material in which the reinforcing fiber material in the invention described in claim 1 is made of at least one reinforcing fiber material of carbon fiber, glass fiber, and aromatic polyamide fiber. .

  Next, a tenth aspect of the present invention is the BMC according to the ninth aspect, wherein the carbon fiber is a pitch-type carbon fiber. Pitch-based carbon fibers are particularly preferred because they have a negative linear expansion coefficient in addition to the conductive properties, and are excellent in dimensional stability on each three-dimensional surface of the molded body.

  Next, in an eleventh aspect of the present invention, the content of the thermosetting polyimide resin having the melting point with respect to the reinforcing fiber material in the invention described in any one of claims 1 to 10 is 60% by weight or more. It is BMC of weight% or less.

  Next, a twelfth aspect of the present invention is a molded body manufactured by molding the BMC according to any one of claims 1 to 11.

  Next, a thirteenth aspect of the present invention relates to a method for manufacturing a molded body, wherein the BMC according to any one of claims 1 to 11 is melted and molded into a predetermined shape, and then a temperature equal to or higher than the melting point of the BMC. It is a manufacturing method of the molded object characterized by heat-curing and heating.

  Since the BMC of the present invention does not contain any solvent, the storage period is semi-permanent, and the storage environment can be stored for a long time without causing any problems except for abnormal environmental conditions such as high temperatures. Next, since the BMC matrix resin is a polyimide resin, the molded product of BMC of the present invention has excellent characteristics such as heat resistance, mechanical characteristics, and dimensional stability. In the production of a molded product using the BMC of the present invention, the BMC is put into a predetermined mold, heated to the melting point of the polyimide resin, molded, and further heated to the thermosetting temperature of the polyimide resin. As a result, the polyimide resin impregnated in the reinforcing fiber material is melted again and a “flow” is generated, so that a uniform molded product can be manufactured by integrating with the reinforcing fiber material. Moreover, the manufacturing method of BMC and the manufacturing method of the molded article using this BMC can be manufactured by very simple operation and process.

  Hereinafter, the bulk molding compound (BMC) of the present invention will be described in detail. The BMC of the present invention is obtained by melting and impregnating a reinforcing fiber material with a thermosetting polyimide resin having a melting point. These BMCs are used as a molding material for obtaining a desired molded product by a molding method such as injection molding or heat compression molding.

  The above-mentioned “thermosetting polyimide resin having a melting point” of the present invention is a reaction product of at least one aromatic tetracarboxylic dianhydride, at least one aromatic diamine and at least one terminal stopper. The melting point is 250 ° C. or less, and the melt viscosity at 200 ° C. is 50,000 cps or less. That is, the “thermosetting polyimide resin having a melting point” is a solid powder at room temperature, and when this powder is heated, the viscosity decreases and melts, and the melting point is shown near 250 ° C. The viscosity at this temperature is 50,000 cps or less, indicating a liquid property.

  As for the properties of this liquid, if the temperature is kept constant at around 200 ° C., the viscosity can be kept almost constant. In this state, the relationship between temperature and viscosity can be kept constant for about 60 minutes. it can. When the temperature is further increased from 200 ° C., thermosetting starts and solidifies completely at a temperature around 330 ° C., and then exhibits excellent heat resistance and mechanical properties as a polyimide resin. .

The term “melting point” used in the present specification means a minimum temperature at which a molten thermosetting polyimide resin having the melting point of the present invention starts to exhibit a stable melt viscosity. The term “stable” means that the variation in melt viscosity does not exceed 100 cps over at least 1 hour.
The viscosity was measured using an AR1000 type rheometer manufactured by TA Instruments (TA Instruments) in parallel mode (diameter 40 mm, gap 500 μm) at a strain of 1.0%. In the measurement, the temperature was scanned at a temperature scanning speed of 10 ° C./min, and data was recorded for 37 minutes every 3 seconds.

Next, in the preparation of a thermosetting polyimide resin having a melting point, (a) BPDA is reacted with an aromatic diamine selected from the group consisting of BAPP, BAPP / SR, APB, TPE-R, and 3,4-ODA. When preparing a polyimide resin by terminating all residual amine groups with an unsaturated carbocyclic monomer acid anhydride selected from the group consisting of CA, HA and IA, for example, the following combinations are possible: .
(I) BPDA // BAPP // CA
(Ii) BPDA // APB // CA
(Iii) BPDA // APB // HA
(Iv) BPDA // BAPP // HA and (v) BPDA // BAPP / IA.

(B) reacting BTDA with an aromatic diamine selected from the group consisting of BAPS-M, BAPP / BAPS-M, m-PDA / BAPS-M, 3,4'-ODA / APB, APB, When preparing a polyimide resin by terminating the residual amine groups with an unsaturated carbocyclic monomer acid anhydride selected from the group consisting of CA, HA and IA. For example, the following combinations are possible.
(I) BTDA // BAPS-M // CA
(Ii) BTDA // BAPP / BAPS-M // CA
(Iii) BTDA // m-PDA / BAPS-M // CA
(Iv) BTDA // 3,4'-ODA / APB // CA
(V) BTDA // APB // CA
(Vi) BTDA // BAPS-M // HA
(Vii) BTDA // APB // HA and (viii) BTDA // BAPS-M / IA.

(C) A case where polyimide resin is prepared by reacting BTDA / BPDA with BAPP and further reacting with CA to produce BTDA / BPDA // BAPP // CA.

(D) A case where a polyimide resin is prepared by reacting PMDA with BAPS-M and further reacting with CA to produce PMDA // BAPS-M // CA.

(E) OPDA is reacted with an aromatic diamine selected from the group consisting of BAPP and BAPS-M, and further reacted with CA to produce OPDA // BAPP // CA or OPDA // BAPS-M // CA When preparing a polyimide resin.

(F) polyimide by reacting DSDA with a diamine selected from the group consisting of BAPS-M and BAPP and CA to form DSDA // BAPS-M // CA or DSDA // BAPP // CA. When preparing a resin.

  Next, in the BMC of the present invention, the reinforcing fiber material is preferably carbon fiber, glass fiber, or aromatic polyamideimide fiber, and carbon fiber is a more preferable reinforcing fiber material. As the carbon fiber, pitch-based or PAN-based carbon fibers can be used. Pitch-based carbon fibers having a negative coefficient of linear expansion are preferably used for applications where the thermal expansion of the molded product is regarded as a problem.

  Further, the form of the reinforcing fiber material is preferably a chopped fiber, and if the reinforcing fiber material is a carbon fiber, it is preferable to use a fiber having an average fiber length of 5 mm to 20 mm. The average fiber diameter is, for example, 0.1 μm or more and 50 μm or less, preferably 1 μm or more and 30 μm or less, and more preferably 1 μm or more and 20 μm or less.

  Next, the BMC manufacturing method of the present invention can be manufactured using a reinforcing fiber material and a thermosetting polyimide resin having a melting point. In the reinforcing fiber material, a thermosetting polyimide resin having a melting point is uniformly dispersed and impregnated between the reinforcing fibers. The content of the thermosetting polyimide resin having a melting point with respect to these reinforcing fiber materials is preferably 20% by weight or more and 60% by weight or less. The content can be selected according to the properties of the molded product, but a more preferable content is in the range of 30 wt% to 55 wt%. Within this range, it is preferable because of excellent dimensional stability in addition to high mechanical properties.

  In the method for producing BMC of the present invention, the reinforcing fiber material (chopped fiber) is heated to at least the melting point of the polyimide resin while stirring with a heating mixer or the like. For example, when the thermosetting polyimide resin (A) having the melting point described in the examples is used as a matrix resin, the reinforcing fiber material is heated in advance to a temperature of 200 to 260 degrees C (preferably 220 to 240 degrees C). . Next, after the reinforcing fiber material reaches the above temperature, a thermosetting polyimide resin powder having a melting point is added, the polyimide resin is melted and impregnated into the reinforcing fiber material, and then directly taken out from the heating mixer to room temperature and cooled. Agglomerates of polyimide resin impregnated reinforcing fibers can be produced. The method for adding a polyimide resin having a melting point in the above impregnation step may be added in the form of a powder, or may be added in a state of being heated and melted in advance.

  Moreover, the addition method of the said polyimide resin has the preferable method of throwing 10-20 weight% with respect to the total charging amount of a reinforced fiber material at 5-10 minute intervals, hold | maintaining a reinforced fiber material at the said preferable temperature. With the charging method, the reinforcing fiber material can be uniformly impregnated.

  Moreover, the following well-known additive may be used for BMC of this invention in the range which does not impair the basic characteristic of the molded article. For example, a filler, a pigment, a solid lubricant, a conductive material, a heat conductive material, and the like. The addition method is not particularly limited. It may be at the time of manufacturing the BMC or at the time of manufacturing the molded body.

  Next, the agglomerate of polyimide resin-impregnated reinforcing fibers cooled to room temperature is pulverized to a predetermined size by a Banbury mixer, a roll mill or the like, and the production as BMC is completed.

  Hereinafter, the present invention will be described in detail based on examples. In addition, this invention is not limited to this Example.

First, adjustment of a polyimide resin having a melting point will be described.
(1) Preparation of thermosetting polyimide resin (A) having a melting point (BPDA // BAPP // ODA // CA)
(Synthesis of amic acid solution)
BPDA (7.35 g, 0.025 mol) was put into NMP (70 g) in the first beaker, and BAPP (20.5 g, 0.05 mol) was put into NMP (70 g) in the second beaker. In addition, ODA (6.00 g, 0.03 mol) was added to NMP (70 g) in the third beaker. Then, each beaker was heated to completely dissolve each monomer. The resulting solution was cooled to room temperature and the BAPP and ODA solutions were transferred to a 500 ml three-necked round bottom flask equipped with a mechanical stirrer, thermometer and addition funnel for adding the BPDA solution. Each beaker was rinsed with an additional 5.0 g of NMP per container and all reactants were dissolved in NMP. Subsequently, the BPDA solution was added dropwise to the mixed solution of the BAPP solution and the ODA solution over 3 hours. Thereafter, CA (5.6 g, 0.05 mol) as a terminator was added dropwise to the round bottom flask over about 1 hour. Thereafter, the mixed solution whose temperature slightly increased was stirred for 1 hour to produce an amic acid solution having a solid content of 30% by weight. The addition of the BPDA solution and CA was performed at room temperature.

(Synthesis of imide powder)
Three 500 ml triples equipped with a Dean-Stark trap filled with toluene, equipped with a reflux condenser, nitrogen inlet / outlet, and a temperature sensor connected via a temperature controller A round neck bottom flask was charged with a 50 g portion of the amic acid solution and 116 g of toluene. A 0.3 g portion of the methanesulfonic acid catalyst was then added to the solution, and the resulting mixture was heated with a mantle heater to reflux at 120-125 ° C. and held for 3-4 hours. The water produced during this process was collected at the bottom of the Dean Stark trap. The reaction solution was then allowed to cool to room temperature. Thereafter, the reaction solution was transferred to a rotary evaporator flask. Toluene was removed from the reaction solution using a rotary evaporator (vacuum degree: 30 hectopascal, heated oil bath temperature: 120 ° C.). The solution remaining in the rotary evaporator flask was then transferred to a mixer containing about 1 liter of tap water and mixed for 5 minutes to precipitate the solution. Next, the precipitate obtained by vacuum filtration was isolated, washed twice with tap water, and dried overnight at 105 ° C. in a forced air dryer to obtain a yellow powder (quantitative yield). Rate: 99.5%). The prepared polyimide resin had a theoretical average molecular weight of 1,266 g / mol. The melting point was less than 250 ° C. and the melt viscosity at 200 ° C. was 1000 cps. The polyimide resin powder was pulverized with a roll mill to a particle size of about 20 to 50 μm.

Synthesis of the following amic acid solution and synthesis of an imide powder were carried out in the same manner as in the preparation of the thermosetting polyimide resin (A) having the melting point (1).
(2) Preparation of thermosetting polyimide resin (B) having a melting point (BPDA // BAPP // HA)
BPDA (7.35 g, 0.025 mol, NMP 70 g), BAPP (20.5 g, 0.05 mol, NMP 70 g), HA (8.2 g, 0.05 mol). The synthesized polyimide powder had a melting point of 200 ° C. and a melt viscosity of 1000 cps.

(3) Preparation of thermosetting polyimide resin (C) having a melting point (α-BPDA // 4,4-ODA // m-PDA // CA)
α-BPDA (8.82 g, 0.03 mol, NMP 70 g), 4,4-ODA (10 g, 0.05 mol, NMP 70 g), m-PDA (0.65 g, 0.006 mol, NMP 70 g), CA ( 7.7 g, 0.07 mol). The synthesized polyimide powder had a melting point of 200 ° C. and a melt viscosity of 1000 cps.

(4) Preparation of thermosetting polyimide resin (D) having a melting point (BPDA // BAPP // CA)
BPDA (7.52 g, 0.026 mol, NMP 70 g), BAPP (20.9 g, 0.10 mol, NMP 70 g), CA (8.0 g, 0.07 mol). The synthesized polyimide powder had a melting point of 200 ° C. and a melt viscosity of 1000 cps.
Example 1

Next, production of BMC using the thermosetting polyimide resin having the above melting point will be described. A pitch-based chopped carbon fiber (DIALEAD K223HG: manufactured by Mitsubishi Chemical Industries, Ltd.) 135 g and 90 g of a thermosetting polyimide resin (A) having a melting point were prepared. The carbon fiber used had an average single fiber diameter of 11 μm, a strand tensile strength of 3,800 MPa, a strand tensile elastic modulus of 900 GPa, and a fiber length of 6 mm. First, the carbon fiber was put in a heating mixer and heated to 240 ° C. while mixing. Next, about 15 g of a thermosetting polyimide resin (A) powder having a melting point was added in 40 minutes. It mixed so that the content rate Wf of a polyimide resin (A) might be 40 weight%. After the addition of the polyimide resin was completed, it was taken out from the heating mixer into a stainless steel bat, spread quickly thinly, and cooled to room temperature as it was to obtain a BMC soul-collected product. Thereafter, the agglomerate of BMC was pulverized into a size of 2 to 5 mm in outer diameter and about 6 to 12 m in length with a bundle of fibers so as not to break the carbon fiber with a magnetic piston crusher. Next, 40 g of the pulverized product is put into a 600 mL plastic container, and a metal cylindrical bar having a diameter of 25 mm, a length of 90 mm, and a weight of 350 g is put and sealed, and stirred for 30 seconds with a shaker to have a carbon fiber primary structure. The BMC (A40) of the present invention was obtained by decomposing to 11 μm and a fiber length of 6 mm.
(Example 2)

In the same manner as in Example 1, BMC (A70) having a content Wf of 70% by weight of the carbon fiber and the thermosetting polyimide resin (A) having a melting point was manufactured.
(Example 3)

In the same manner as in Example 1, a BMC (A15) having a carbon fiber and a content Wf of a thermosetting polyimide resin (A) having a melting point of 15% by weight was manufactured.
Example 4

As in Example 1, BMC (B40) having a carbon fiber and a content Wf of a thermosetting polyimide resin (B) having a melting point of 40% by weight was manufactured.
(Example 5)

In the same manner as in Example 1, BMC (C40) having a carbon fiber and a thermosetting polyimide resin (C) having a melting point Wf content of 40 wt% was manufactured.
(Example 6)

As in Example 1, BMC (D40) having a carbon fiber and a content Wf of a thermosetting polyimide resin (D) having a melting point of 40% by weight was manufactured.
(Example 7)

Next, the manufacturing method of the molded article using BMC of this invention is demonstrated. A molded product was manufactured using the BMC (A40) synthesized in Example 1. First, BMC (A40) was preheated to 240 ° C. and held in a molten state. In addition, the uneven mold was preheated to 240 ° C., and 180 g of BMC (A40) heated to 240 ° C. was placed in the center of the concave mold. Thereafter, the convex mold was placed, and left still for 5 minutes only with the convex weight (about 11 kg). Next, the pressure was increased to 3 Mpa, allowed to stand for 3 minutes, pressurized to 5 Mpa, allowed to stand for 3 minutes, further pressurized to 10 Mpa, and pressurized in a stepwise manner for 3 minutes. Then, after pressurizing directly to 20 Mpa and confirming that the pressure does not fluctuate at 20 Mpa, the temperature of the molding machine is increased to 335 ° C. at a heating rate of 1 ° C / min, and firing is performed at this temperature for 4 hours. It was. After firing, it was naturally cooled and the pressure was released when the temperature of the mold reached room temperature. The obtained panel had a thickness of 4.5 mm and a weight of 168 g. FIG. 1 shows the ultrasonic flaw detection test results of this example. The ultrasonic flaw detection test apparatus used was an apparatus manufactured by Hitachi, with a probe of 10 MHz and a measurement pitch of 1 mm. As is clear from FIG. 1, a molded product (150 mm square panel) free from defects such as voids could be produced.
(Example 8)

A molded product was manufactured using BMC (B40) under the same conditions as in Example 7. As a result of ultrasonic testing of this molded product, a molded product (150 mm square panel) free from defects such as voids could be obtained.
Example 9

A molded product was manufactured using BMC (C40) under the same conditions as in Example 7. As a result of ultrasonic testing of this molded product, a molded product (150 mm square panel) free from defects such as voids could be obtained.
(Example 10)

A molded product was manufactured using BMC (D40) under the same conditions as in Example 7. As a result of ultrasonic testing of this molded product, a molded product (150 mm square panel) having no defects such as voids could be obtained.
(Comparative Example 1)

A molded product was manufactured using BMC (A70) under the same conditions as in Example 7. 180 g of BMC (A70) was put into the mold, and the resin inside the mold flowed to the outside while being pressurized stepwise. The molded product lacked the reinforcing fiber material and was partially damaged when the molded product was removed from the mold. If the content of the polyimide resin is excessive, the resin flows out from the mold and the molded product corresponding to the Wf value set in the BMS manufacturing stage cannot be manufactured. As a result, many voids occur and normal molding occurs. I could not get the goods. The ultrasonic flaw detection test results of the molded product of this comparative example are shown in FIG.
(Comparative Example 2)

  A molded product was manufactured using BMC (A15) under the same conditions as in Example 7. Almost normal molded products could be obtained, but sufficient mechanical properties could not be obtained. This was a defective product in which the fibers were not integrated because there was too little polyimide resin that binds the reinforcing fibers together, and the molded product was void from the appearance.

  The molded product of BMC of the present invention has excellent mechanical properties, heat resistance, dimensional stability, low linear expansion properties, etc., and wafers for electrical / electronic equipment, machinery, automobiles, aerospace equipment, semiconductor manufacturing equipment Since it can be widely used as a material for parts in all industries such as fixed bases and general industrial equipment, its industrial value is great.

2 is an ultrasonic flaw detection photograph of a molded article having a Wf of 40% by weight according to Example 1 of the present invention. 3 is an ultrasonic inspection photograph of a molded article having a Wf of 70% by weight according to Comparative Example 1 of the present invention.

Claims (13)

  A bulk molding compound comprising a reinforcing fiber material impregnated with a matrix resin, wherein the matrix resin is a thermosetting polyimide resin having a melting point.   The thermosetting polyimide resin having the melting point is a reaction product of at least one aromatic tetracarboxylic dianhydride, at least one aromatic diamine, and at least one terminal stopper. The listed bulk molding compound.   The thermosetting polyimide resin having the melting point includes a first aromatic tetracarboxylic dianhydride, a second aromatic tetracarboxylic dianhydride, at least one aromatic diamine, and at least one terminal stopper. The first aromatic tetracarboxylic dianhydride is a reaction product of 5 wt% or more and 40 wt% or less based on the total weight of the first and second aromatic tetracarboxylic dianhydrides. The second aromatic tetracarboxylic dianhydride is present in an amount of 60 wt% or more and 95 wt% or less based on the total weight of the first and second aromatic tetracarboxylic dianhydrides. The bulk molding compound of claim 2 present in an amount.   The bulk molding compound according to claim 2 and 3, wherein the aromatic tetracarboxylic dianhydride has two or more aromatic rings in its chemical structure.   The thermosetting polyimide resin having the melting point is a reaction product of at least one aromatic tetracarboxylic dianhydride, two aromatic diamines, and at least one terminal terminator, and the two aromatics. At least one of the group diamines has one or more oxygen bonds in its chemical structure and is present in an amount of at least 50% by weight relative to the total weight of the two aromatic diamines. 2. Bulk molding compound according to 2.   The bulk molding compound according to claim 5, wherein the aromatic diamine has at least one ether bond in its chemical structure.   The terminal terminator is an unsaturated carbocyclic monomer acid anhydride, and the unsaturated carbocyclic monomer acid anhydride has a melting point of less than 250 degrees C and a melt viscosity at 200 degrees C of 500 centipoise ( The bulk molding compound according to any one of claims 2, 3, and 5, wherein an oligomer having a viscosity of not less than cps and not more than 50,000 cps is formed.   The bulk molding compound according to any one of claims 1 to 7, wherein the thermosetting polyimide resin having the melting point has a melting point of 250 ° C or lower and a melt viscosity at 200 ° C of 50,000 cps or lower.   The bulk molding compound according to claim 1, wherein the reinforcing fiber material is at least one reinforcing fiber material of carbon fiber, glass fiber, and aromatic polyamide fiber.   The bulk molding compound according to claim 9, wherein the carbon fiber is a pitch-based carbon fiber.   The bulk molding compound according to any one of claims 1 to 10, wherein a content of the thermosetting polyimide resin having a melting point with respect to the reinforcing fiber material is 20 wt% or more and 60 wt% or less.   A molded product obtained by molding the bulk molding compound according to any one of claims 1 to 11. The molded article according to claim 12, wherein the bulk molding compound according to any one of claims 1 to 11 is melted and molded into a predetermined shape, and then heated to a temperature equal to or higher than a melting point of the bulk molding compound to be thermally cured. Manufacturing method.