JP2010270229A - Heat-resistant resin composition, fiber-reinforced prepreg and fiber-reinforced composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition having viscosity-regulating ability equal to that of an epoxy resin, and having heat resistance near to that of a polyimide-based resin, and to provide a prepreg and a fiber-reinforced composite material, using the heat-resistant resin composition as a matrix resin. <P>SOLUTION: The heat-resistant resin composition is obtained by dispersing powder of a maleimide compound having the melting point of 120-220&deg;C in a base epoxy resin containing at least an epoxy resin and a curing agent as the main materials. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention provides a heat-resistant material such as a robot member used in a high-temperature environment, a roll used in an oven that requires heat resistance, a printed circuit board that requires solder heat resistance, and a heat-resistant rod for a tension member of an electric cable. Resin composition having effective heat resistance for reinforced fiber composite materials requiring high performance, reinforced fiber prepreg using the heat resistant resin composition as a matrix resin, and reinforced fiber composite materials requiring heat resistance About.

  As a resin (matrix resin) for a reinforcing fiber composite material, an epoxy resin or the like is generally used. Epoxy resins have a wide range of specifications from low-viscosity liquids to solids, and it is possible to adjust the viscosity to a low level by filament winding method or pultrusion method to be impregnated at room temperature. It is also possible to adjust the viscosity to a suitable value by mixing the solid and liquid prepregs that are impregnated at a high temperature and being semi-solid at room temperature, and mixing them in an optimal composition. It is suitable as a resin.

  There are also polyfunctional resins having three or more functional groups that react with the curing agent, and the heat resistance can be improved to some extent.

  However, even when various types of epoxy resins are combined, the glass point transition temperature (hereinafter referred to as “Tg”), which is a measure for heat resistance, is at most about 220 ° C., and is always an environment of 200 ° C. or higher. It is difficult to obtain a resin having a Tg of 250 ° C. or higher, which is necessary for solder heat resistance without containing a roll in a furnace, a robot in the furnace, or lead used below.

  On the other hand, it is practiced to use a polyimide resin with emphasis on heat resistance. For example, a maleimide compound, which is one of the raw materials for polyimide resins, is modified with a diamine compound so as to have a viscosity suitable for prepreg and the like (for example, see Patent Document 1). However, it takes time to control the denaturation reaction, and the cost becomes high.

  In addition, there are those modified with a triazine monomer to adjust the viscosity from a viscous liquid to a solid ("BT resin" manufactured by Mitsubishi Gas Chemical Co., Ltd .: trade name), Viscosity cannot be adjusted over a wide range.

  Also, development of a maleimide compound-modified epoxy resin has been attempted in order to obtain a resin having both the viscosity adjusting ability of the epoxy resin and the heat resistance of the polyimide resin (see, for example, Patent Document 2). However, maleimide compounds have poor compatibility with epoxy resins and solvents, and the amount of maleimide compound added cannot be increased beyond a certain level, and sufficient heat resistance cannot be obtained.

Japanese Patent Laid-Open No. 5-170950 JP-A-5-239426

  Accordingly, an object of the present invention is to provide a resin composition having a viscosity adjusting ability similar to that of an epoxy resin and having heat resistance close to that of a polyimide resin, and a reinforced fiber prepreg using the heat resistant resin composition as a matrix resin, and It is to provide a reinforced fiber composite material.

  The above object is achieved by the heat resistant resin composition, the reinforcing fiber prepreg and the reinforcing fiber composite material according to the present invention. In summary, according to one aspect of the present invention, a maleimide compound powder having a melting point of 120 to 220 ° C. is dispersed in a base epoxy resin containing at least an epoxy resin as a main agent and a curing agent. A heat resistant resin composition is provided.

  According to one embodiment, as the powder of the maleimide compound, a powder having a residual rate of 5 wt% or less at # 100 mesh (a sieve opening of 0.154 mm) is used. Preferably, a powder having a residual rate of 1 wt% or less at # 150 mesh (screen opening 0.109 mm) is used.

  According to another embodiment, the addition amount of the maleimide compound is in the range of 5 to 400 parts by weight with respect to 100 parts by weight of the epoxy resin as the main agent.

  According to another embodiment, a thermoplastic resin is added to the base epoxy resin in the range of 5 to 30 parts by weight with respect to 100 parts by weight of the epoxy resin as the main agent. The thermoplastic resin may be a phenoxy resin, a polyetherimide resin, a polyether sulfone resin, a polyvinyl formal, or the like.

  According to another embodiment, the maleimide compound is bismaleimide.

  According to another aspect of the present invention, the heat-resistant resin composition having any one of the above-described structures is impregnated in a unidirectional array product of reinforcing fibers, a woven product, a braid, or a combination thereof. A reinforcing fiber prepreg is provided.

  According to another aspect of the present invention, the heat-resistant resin composition having any one of the above structures is impregnated in a unidirectional array of reinforcing fibers, a woven product, a braid, or a combination thereof and heat-cured. A reinforced fiber composite material is provided. The heat curing is performed at a temperature higher than the melting point of the maleimide compound.

  According to the present invention, it is possible to obtain a resin composition having a viscosity adjustment capability similar to that of an epoxy resin and having heat resistance close to that of a polyimide resin.

  In other words, by using the heat-resistant resin composition of the present invention as a matrix resin, it has a wide range of heat resistance from liquid resin suitable for filament winding or pultrusion method impregnated at room temperature to semi-solid resin at room temperature used for prepreg. It is possible to obtain a high-strength resin for reinforcing fiber composite materials.

  Moreover, according to this invention, the reinforced fiber prepreg and reinforced fiber composite material which have the heat resistance which used the said heat resistant resin composition as matrix resin can be provided.

FIG. 1 is a photograph showing bismaleimide in a recrystallized base epoxy resin. FIG. 2 is a photograph of a thin film state of a resin composition in which bismaleimide is uniformly dispersed in a base epoxy resin. It is a graph which shows the DSC measurement result of uncured resin. It is a figure explaining the preparation process of a reinforced fiber prepreg. It is a figure which shows schematic structure of a reinforced fiber composite material. It is a figure explaining a strand impregnation process. It is a figure explaining the strand high temperature strength measuring method.

  Hereinafter, the heat resistant resin composition, the reinforcing fiber prepreg and the reinforcing fiber composite material according to the present invention will be described in more detail.

  As a result of conducting many research experiments, the present inventor has a viscosity adjusting ability similar to that of an epoxy resin by dispersing the maleimide compound in a powder state instead of being dissolved in the epoxy resin. A resin composition having heat resistance close to that of a resin, that is, a heat resistant resin composition could be obtained.

  That is, the heat-resistant resin composition according to the present invention has a melting point of 120 in a resin (hereinafter referred to as “base epoxy resin”) containing an epoxy resin (main agent) and its curing agent (further, a curing aid). A maleimide compound powder at ˜220 ° C. is dispersed.

  Here, as the powder of the maleimide compound, a powder having a residual rate of 5 wt% or less at # 100 mesh (a sieve opening of 0.154 mm) is used. Preferably, a powder having a residual rate of 1 wt% or less at # 150 mesh (screen opening 0.109 mm) is used. Moreover, it is preferable that the addition amount of a maleimide compound is the range of 5-400 weight part with respect to 100 weight part of epoxy resins (main ingredient).

  More specifically, maleimide compounds, especially bismaleimide (hereinafter referred to as “BMI”) have low compatibility with the base epoxy resin, and once they are compatible at a high temperature of 120 ° C. or higher, they are cooled to room temperature. Will recrystallize and cannot be uniform.

  FIG. 1 is a photograph showing BMI in a recrystallized base epoxy resin. However, when BMI is finely powdered and dispersed in the base epoxy resin, it becomes uniform and can be handled as a one-part resin. FIG. 2 is a photograph of a thin film state of a resin composition in which BMI is uniformly dispersed in a base epoxy resin.

  Since BMI is dispersed as a solid, the handleability of the resin composition can be controlled by the viscosity characteristics of the epoxy resin which is a dispersion medium in handling. Therefore, the resin composition can be adjusted by blending an epoxy resin from a liquid one to a semi-solid one for prepreg.

  On the other hand, in curing by heating, when the temperature exceeds the melting point of crystalline BMI, BMI melts all at once and reacts with the epoxy resin as the main agent or the curing agent of the epoxy resin to form a uniform state. Therefore, the effect of improving heat resistance by BMI can be obtained.

  The maleimide compound to be used is powdered in order to uniformly disperse it in the base epoxy resin. As the powder, the residual rate at # 100 mesh (screen opening 0.154 mm) is 5 wt% or less. Use powder. Preferably, a powder having a residual rate of 1 wt% or less at # 150 mesh (screen opening 0.109 mm) is used. When powder of such a size is not used, the cured resin composition is divided into a BMI rich part and an epoxy resin rich part, and the performance as a resin is not exhibited.

  The addition amount of the maleimide compound is suitably in the range of 5 to 400 parts by weight, preferably in the range of 10 to 200 parts by weight, with 100 parts by weight of the epoxy resin (main agent). If it is less than 5 parts by weight, the effect of improving the heat resistance of the resin composition is small. Moreover, when it exceeds 400 weight part, the handling as resin of a resin composition will become difficult.

  The epoxy resin (main agent) to be used is not particularly specified, but the following can be applied.

  For example, bisphenol A type epoxy, bisphenol F type epoxy, phenol novolac type epoxy, cresol novolac type epoxy, diaminodiphenylmethane (DDM) type epoxy, trimethylolpropane polyglycidyl ether and other aliphatic epoxy, polyglycol diglycidyl ether, etc. Reactive diluents and the like.

  As the curing agent to be used, any curing agent that hardens the epoxy resin can be used. Examples of the amine curing agent include aromatic polyamines such as diaminodiphenylsulfone (DDS) and metaxylylenediamine, cyclic aliphatic polyamines such as isophoronediamine, and aliphatic polyamines such as tetraethylenetriamine. In addition, acid anhydride curing agents include acid anhydrides such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhymic anhydride, ethanetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, Acid dianhydrides such as cyclopentanecarboxylic dianhydride and benzophenone carboxylic dianhydride can be used. As a curing agent auxiliary, dichlorodimethylurea (DCMU) or the like can be used.

  Examples of maleimide compounds include 4,4′-diphenylmethane bismaleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide, 4 -Methyl-1,3-phenylene bismaleimide, 1,6'-bismaleimide- (2,2,4-trimethyl) hexane, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1 1,3-bis (3-maleimidophenoxy) benzene, 1,3-bis (4-maleimidophenoxy) benzene, and the like can be used.

  In the base epoxy resin constituting the heat-resistant resin composition of the present invention, it is effective to add a thermoplastic resin such as a phenoxy resin in order to improve the toughness after curing and reduce the resin flow during curing. is there. As the thermoplastic resin, a phenoxy resin, a polyetherimide resin, a polyether sulfone resin, a polyvinyl formal, or the like can be suitably used.

  In addition, when the heat resistant resin composition is cured, it is necessary to cure at a temperature higher than the melting point of the added BMI. If left at a temperature lower than the melting point for a long time, only the epoxy resin (main agent) reacts with the curing agent, and then the BMI itself melts even if the temperature is higher than the melting point. As a result, the resin composition does not exhibit sufficient performance as a resin.

  FIG. 3 is an exothermic curve of DSC measurement of uncured resin at 10 ° C./min when dicyandiamide is used as a curing agent and DCMU (dichlorodimethylurea) is used as a curing aid.

  Endothermic peak 1 is considered to be the heat of fusion of BMI. The subsequent two peaks are presumed to be the reaction heat between the epoxy resin and the curing agent, the reaction heat between the BMI and the generated amine compound, the reaction heat of the BMI double bond, and the like.

Examples 1-6, Comparative Examples 1-4
Various heat resistant resin compositions according to the present invention were prepared by changing the blending components and blending ratios, and the heat resistance was measured. The results are shown in Table 1 below.

Example 1
As the epoxy resin (main agent), bisphenol A-based epoxy resin (YD-128 manufactured by Toto Kasei) and tetraglycidyl diaminodiphenylmethane (YH-434 manufactured by Toto Kasei) were used. Dicyandiamide (Dicy) was used as a curing agent, and dichlorodimethylurea (DCMU) was used as a curing aid. As the maleimide compound, diaminodiphenylmethane bismaleimide powder (BMI1000H manufactured by Daiwa Kasei) was used. The powder (BMI1000H) used here had a residual rate of 0.3 wt% at # 180 mesh (mesh opening 0.091 mm).

These components were mixed in the following composition. The maleimide compound was dispersed in a base epoxy resin composed of an epoxy resin (main agent) curing agent and a curing aid.
・ Epoxy resin (main agent)
Bisphenol A epoxy (Toto Kasei YD-128): 30g
Tetraglycidyldiaminodiphenylmethane (YH-434 manufactured by Tohto Kasei): 70 g
・ Curing agent (curing aid)
Dicyandiamide: 8g
DCMU: 8g
・ Maleimide compound Bismaleimide (BMI1000H manufactured by Daiwa Kasei): 60 g

  The obtained resin composition was a viscous brownish brown turbid color at room temperature. This resin composition was cured at 210 ° C. for 2 hours after preliminary curing at 170 ° C. for 30 minutes, changing the temperature setting of the oven. Thereafter, the sample was taken out, cooled, processed into a test piece, and TMA was measured to measure Tg. As a result, as shown in Table 1, it was Tg = 255 ° C.

(Examples 2 to 6)
As Examples 2 to 6, resin compositions were prepared in the same manner as in Example 1 with the blending and blending ratios shown in Table 1.

  In Example 3, tetraglycidyldiaminodiphenylmethane (YH-434 manufactured by Tohto Kasei) and trimethylolpropane polyglycidyl ether (YH-300 manufactured by Tohto Kasei) were used as the epoxy resin (main agent). In Examples 4 and 5, as an epoxy resin (main agent), trimethylolpropane is used in addition to bisphenol A-based epoxy resin (YD-128 manufactured by Tohto Kasei) and tetraglycidyldiaminodiphenylmethane (YH-434 manufactured by Tohto Kasei). Polyglycidyl ether (YH-300 manufactured by Tohto Kasei) was also used.

  In Examples 2 to 6, as in Example 1, 8 parts by weight of dicyandiamide as a curing agent and 8 parts by weight of DCMU as a curing agent auxiliary were added to 100 parts by weight of the epoxy resin (main agent).

  In Example 4, a fine powder of metaxylylenediamine bismaleimide (BMI 3000H manufactured by Daiwa Kasei) was used as the maleimide compound. The powder (BMI3000H) used here had a residual rate of 0.3 wt% at # 180 mesh (mesh opening 0.091 mm). In Example 6, 15 parts by weight of phenoxy resin (YP-70 manufactured by Toto Kasei) as an additive was added to 100 parts by weight of epoxy resin (main agent).

  Similarly to Example 1, the obtained resin composition was cured at 210 ° C. for 2 hours by changing the temperature setting of the oven after preliminary curing at 170 ° C. for 30 minutes. Thereafter, the sample was taken out, cooled, processed into a test piece, and TMA was measured to measure Tg. The test methods are the same unless otherwise noted in the remarks.

  As a result, Tg values as shown in Table 1 were shown.

(Comparative Examples 1-4)
As Comparative Examples 1 to 4, resin compositions were prepared in the same manner as in Example 1 with the blending components and blending ratios shown in Table 1.

  In Comparative Example 2, bisphenol A type epoxy resin (YD-128 manufactured by Toto Kasei) and trimethylolpropane polyglycidyl ether (YH-300 manufactured by Toto Kasei) were used as the epoxy resin (main agent).

  In Comparative Examples 1 to 4, as in Example 1, 8 parts by weight of dicyandiamide as a curing agent and 8 parts by weight of DCMU as a curing agent auxiliary were added to 100 parts by weight of the epoxy resin (main agent).

  In Comparative Example 3, a flaky BMI of about 2 mm, which is a DDM bismaleimide, was used as the maleimide compound. The flaky BMI used here had a residual rate of approximately 100 wt% at # 100 mesh.

  In Comparative Examples 1 to 3, the obtained resin compositions were cured at 210 ° C. for 2 hours by changing the oven temperature setting after preliminary curing at 170 ° C. for 30 minutes, as in Examples 1 to 6. went. In Comparative Example 4, the curing conditions were set to curing conditions 2 different from those of other Comparative Examples 1 to 3 and Examples 1 to 6. That is, first, after the preliminary curing at 90 ° C. × 5 hours, the temperature setting of the oven was changed and the curing was performed at 210 ° C. × 2 hours. Thereafter, the sample was taken out, cooled, processed into a test piece, and TMA was measured to measure Tg. The test methods are the same unless otherwise noted in the remarks.

  As a result, Tg values as shown in Table 1 were shown.

  In Comparative Example 4, although the clear inflection point was unknown, the TMA curve began to be disturbed from around 150 ° C.

  As understood above, according to the present invention, it was possible to obtain a resin composition having a viscosity adjusting ability similar to that of an epoxy resin and having heat resistance close to that of a polyimide resin.

Example 7 (Example of prepreg)
The heat-resistant resin composition according to the present invention is effective as a prepreg matrix resin. That is, the resin composition of the present invention can produce a reinforced fiber prepreg by impregnating a unidirectionally aligned product, a woven product, a braid, or a combination thereof.

  Carbon fiber, glass fiber, organic fiber, and other various fibers can be used as the reinforcing fiber. In the heat-resistant resin composition of the present invention, the content relative to the entire prepreg can be 20 to 70% by volume.

Explaining one example, a resin composition according to the resin formulation of Example 6 was prepared. Using a hot-melt resin coater, as shown in FIGS. 4A, 4B, and 4C, the resin composition 3 is placed on a release paper 2 having a width of 50 cm (approx. 37 g / m ^2). 30 μm thickness) to prepare a resin film 3 having a width of 30 cm. This resin film-coated paper 1 is set in a drum winder, and carbon fiber TR50 (trade name) 4 manufactured by Mitsubishi Rayon Co., Ltd. is wound so as to have a fiber basis weight of 150 g / m ^2. The coated paper 1 was covered and impregnated using a hot press roller to produce a unidirectional prepreg 10.

  The prepreg 10 thus obtained also had good tackiness (adhesiveness) of the resin.

Example 8 (Example of composite material)
The heat-resistant resin composition according to the present invention is effective as a matrix resin for reinforcing fiber composite materials. In other words, the reinforced fiber composite material can be produced by impregnating the resin composition of the present invention into a unidirectional array product of reinforcing fibers, a woven product, a braid, or a combination thereof, and then heat-curing.

  Carbon fiber, glass fiber, organic fiber, and other various fibers can be used as the reinforcing fiber. The content of the resin composition of the present invention relative to the entire prepreg can be 20 to 70% by volume.

  Explaining one example, as shown in FIG. 5, using the prepreg 10 produced in Example 7, 14 layers were laminated in one direction, and a flat plate 20 having a thickness of 2 mm was produced by vacuum bag molding.

  Curing conditions in the oven were as follows: from room temperature at a rate of 5 ° C./minute, kept at 170 ° C. for 30 minutes, then raised to 210 ° C. at a rate of 5 ° C./minute and kept for 2 hours. Then, it was naturally cooled and cooled to room temperature.

  The finished unidirectional CFRP (carbon fiber reinforced composite material) was cut into test piece dimensions in accordance with JIS K7074 and subjected to a bending test at room temperature and 220 ° C. environment.

For comparison, 17 layers of Mitsubishi Rayon heat-resistant prepreg TR270G125SM (Mitsubishi Rayon carbon fiber TR50 and heat-resistant resin prepreg with a fabric weight of 125 g / m ² ) were laminated, and a 2 mm thick flat plate was formed under the same conditions as above. The same evaluation was made.

  The results obtained for bending strength and flexural modulus are shown in the table below.

  As another example, a resin composition according to the resin formulation of Example 3 was prepared. The strand strength was measured according to JIS R 7608 using a strand obtained by impregnating a carbon fiber tow (bundle) with this resin composition and heat-curing the strand. The carbon fiber used was TR50S15L (trade name) manufactured by Mitsubishi Rayon Co., Ltd.

  More specifically, as shown in FIG. 6, a resin tank 50 heated to 40 ° C. is filled with the resin composition, and a roller 51 rotating at a constant speed is driven by a motor and fed from a supply roll 41. The carbon fiber tow 4 was impregnated with resin by a roll coat and wound on a steel frame 52. The frame 52 was placed in an oven as it was and cured under conditions of 170 ° C. × 30 minutes + 210 ° C. × 2 hours.

  The cured strand had a resin adhesion amount of about 48% by volume. The obtained strands were tabbed and only the tensile strength was evaluated.

  As shown in FIG. 7, the test environment was room temperature, and the ribbon heater H was wound around a range of about 5 cm in the central portion of the strand S, and the strength when the temperature was in the range of 200 to 220 ° C. was also evaluated. .

  The strand used as a comparison was a general epoxy resin formulated with the following blending amounts, and the strand was produced in the same process and evaluated in the same manner. The resin adhesion amount was 45% by volume.

<Comparison resin>
Bisphenol A epoxy (YD-128 manufactured by Tohto Kasei): 100 g
Dicyandiamide (Dicy): 4g
DCMU: 4g

  The test results (average value) when the number of sample pieces is n = 10 are shown in the table below.

  As understood from the above, according to the present invention, by using as a matrix resin a resin composition having a viscosity adjustment capability similar to that of an epoxy resin and having heat resistance close to that of a polyimide resin, at room temperature. A resin for a reinforced fiber composite material having high heat resistance can be obtained in a wide range from a liquid resin suitable for impregnating filament winding or a pultrusion method to a semisolid resin at room temperature used for a prepreg.

  Moreover, according to this invention, the reinforced fiber prepreg and reinforced fiber composite material which have the heat resistance which used the said heat resistant resin composition as matrix resin can be provided.

DESCRIPTION OF SYMBOLS 1 Resin film coated paper 2 Release paper 3 Resin film 4 Carbon fiber 10 Prepreg 20 Reinforced fiber composite material

Claims (10)

  A heat-resistant resin composition comprising a maleimide compound powder having a melting point of 120 to 220 ° C. dispersed in a base epoxy resin containing at least an epoxy resin as a main agent and a curing agent.   2. The heat-resistant resin composition according to claim 1, wherein the maleimide compound powder is a powder having a residual rate of 5 wt% or less at # 100 mesh (a sieve opening of 0.154 mm).   2. The heat-resistant resin composition according to claim 1, wherein the maleimide compound powder is a powder having a residual rate of 1 wt% or less at # 150 mesh (a sieve opening of 0.109 mm).   The heat-resistant resin composition according to any one of claims 1 to 3, wherein the maleimide compound is added in an amount of 5 to 400 parts by weight with respect to 100 parts by weight of the epoxy resin as the main agent. object.   5. The heat-resistant resin composition according to claim 1, wherein a thermoplastic resin is added to the base epoxy resin in a range of 5 to 30 parts by weight with respect to 100 parts by weight of the epoxy resin as the main agent. object.   The resin composition according to claim 5, wherein the thermoplastic resin is a phenoxy resin.   The heat-resistant resin composition according to any one of claims 1 to 6, wherein the maleimide compound is bismaleimide.   Reinforced fiber, wherein the heat-resistant resin composition according to any one of claims 1 to 7 is impregnated into a unidirectionally aligned product, a woven product, a braid, or a combination thereof. Prepreg.   The heat-resistant resin composition according to any one of claims 1 to 7 is impregnated into a unidirectionally arranged product of reinforcing fibers, a woven product, a braid, or a combination thereof, and is heat-cured. Reinforced fiber composite material.   The reinforcing fiber composite material according to claim 9, wherein the heat curing is performed at a temperature higher than a melting point of the maleimide compound.