JP5671800B2 - Epoxy resin composition for honeycomb sandwich panel, prepreg for honeycomb sandwich panel and honeycomb sandwich panel using the same - Google Patents

Description

  The present invention relates to an epoxy resin composition for a honeycomb sandwich panel, a prepreg for a honeycomb sandwich panel using the same, and a honeycomb sandwich panel.

In a self-adhesive prepreg that can improve panel productivity without applying a film adhesive during the manufacture of honeycomb panels, it is extremely important to increase the toughness of the matrix resin and the resin flow characteristics.
Conventionally, examination of high toughness of an epoxy resin by rubber or super engineering plastic has been advanced (for example, see Patent Documents 1 to 3).

Japanese Patent Publication No. 1-57130 JP-A-9-118738 International Publication No. 99/02586

However, the compounding using rubber and the compounding using super engineering plastic have the following disadvantages and problems, respectively, and there is no material on the market so far.
(Defects and issues in the production of rubber compounded epoxy resin compositions)
Conventional rubber components that can be added to epoxy resin compositions include solid rubber and liquid rubber.
When solid rubber is used as the rubber component, it is necessary to blend 8 to 10 parts by mass or more of high molecular weight solid rubber with respect to 100 parts by mass of the epoxy resin in order to develop sufficient self-adhesiveness.
In general, in order to mix the solid rubber with the epoxy resin, for example, there is a method of making the solid rubber into a solution with a solvent and mixing it with the epoxy resin. In this case, it is necessary to remove the solvent from the epoxy resin composition after the final blending or to remove the solvent in a subsequent step (prepreg impregnation or the like). When such a solvent removal step is present in the prepreg or prepreg resin production process, the productivity of the prepreg or prepreg resin is lowered, and the residual solvent adversely affects the product characteristics. It is also not desirable from an environmental point of view.
For this reason, the present inventor has conceived of mixing an epoxy resin and a solid rubber without using a solvent.
In order to mix a large amount of solid rubber with an epoxy resin without using a solvent, it is usually necessary to heat and mix the solid rubber and the epoxy resin with a dedicated kneading apparatus such as a kneader or a roll. When the epoxy resin composition contains an epoxy resin, a curing agent, and solid rubber, the system becomes high temperature when the composition is mixed with the kneading apparatus as described above, and the epoxy resin composition easily gels. Mixing itself is difficult, and there is a problem that the epoxy resin composition itself is cured.
(Disadvantages and problems of epoxy resin composition containing liquid rubber)
In the compounding system using liquid rubber, a dedicated kneading apparatus is not required. However, since the molecular weight of the rubber itself is small, the toughness of the epoxy resin cannot be increased even if a large amount is added.
(Defects and problems of prepreg for honeycomb sandwich panel using epoxy resin composition containing super engineering plastic)
In order to increase the toughness of the epoxy resin to a level at which sufficient self-adhesiveness can be expressed with Super Engineering Plastics, it is necessary to add 40 to 50 parts by mass or more of engineering plastic to 100 parts by mass of the epoxy resin. is there. However, the resulting matrix resin is hard and unwieldy, not only lowering the productivity of the subsequent prepreg, but also reducing the workability (tack, drape) of the resulting prepreg and forming defects (voids) during curing. .
In addition, as a method of adding a large amount of engineering plastics to epoxy resin, a technology to blend finely divided engineering plastics in the particle state has also been introduced, but in the case of particles soluble in epoxy resin, at the time of manufacturing resin or prepreg Since particles are easily dissolved by heating, it is difficult to control the dissolution level of particles in the prepreg, and the problem that the tackiness of the resulting particle-containing prepreg tends to disappear is left. In the case of engineering plastic particles that do not dissolve in the epoxy resin, the effect of improving the toughness as a matrix is small, and the problem of tack disappearing easily remains as a particle-containing prepreg.
Furthermore, the inventor of the present application has found that when the epoxy resin composition for honeycomb sandwich panels does not contain a filler, the minimum viscosity of the epoxy resin composition needs to be increased more than necessary, so that workability is poor and toughness is low. .
Therefore, the present invention firstly has high toughness, excellent mixing property between solid rubber and epoxy resin, suitable viscosity, excellent workability (for example, impregnation property to fiber base material), and hardly gelled. An object is to provide an epoxy resin composition for a honeycomb sandwich panel.
Secondly, the present invention can be manufactured easily by a general-purpose mixing apparatus, such as a mixing property and productivity of a solid rubber and an epoxy resin (for example, it is not necessary to use a solvent and a removal step is unnecessary). It is an object of the present invention to provide a method for producing an epoxy resin composition for a honeycomb sandwich panel which is excellent in the formation of a gel and is not easily gelled.
Thirdly, an object of the present invention is to provide a prepreg for a honeycomb sandwich panel that is excellent in workability (for example, tack, drape) and that provides a tough honeycomb sandwich panel.
Finally, the present invention aims to provide a tough honeycomb sandwich panel.

As a result of earnest research to solve the above problems, the inventor of the present application contains at least one epoxy resin A, a rubber master batch, a filler, and a curing agent, and the rubber master batch is the epoxy resin. An epoxy resin composition for a honeycomb sandwich panel containing at least a solid rubber having a functional group capable of reacting with A and a liquid rubber has high toughness, excellent mixing properties between the solid rubber and the epoxy resin, and an appropriate viscosity. And found to have excellent workability (for example, impregnation into a fiber substrate).
Further, the inventor of the present application is a master batch process for obtaining the rubber master batch by kneading at least the solid rubber and the liquid rubber, the rubber master batch, the epoxy resin A, the filler, A method for producing an epoxy resin composition for a honeycomb sandwich panel comprising mixing a curing agent to obtain an epoxy resin composition for a honeycomb sandwich panel of the present invention is provided. It has been found that (for example, it is not necessary to use a solvent and a removal step is unnecessary, and it can be easily produced by a general-purpose mixing apparatus), and gelation hardly occurs.
In addition, the inventor of the present application has a prepreg for a honeycomb sandwich panel obtained by using the epoxy resin composition for a honeycomb sandwich panel of the present invention and a fiber base material, which has excellent workability (eg, tack, drape) and is tough. It has been found that a honeycomb sandwich panel can be obtained.
The inventor of the present application has found that the honeycomb sandwich panel obtained by laminating and bonding the prepreg for the honeycomb sandwich panel of the present invention and the honeycomb core is tough, and completed the present invention.

That is, this invention provides the following 1-15.
1. Containing at least one epoxy resin A, a rubber masterbatch, a filler, and a curing agent;
The rubber master batch, a solid rubber having a functional group capable of reacting with the epoxy resin A, at least viewed contains a liquid rubber,
The functional group is a hydroxy group, an amino group, a carboxyl group (—COOH) or a glycidyl group;
An epoxy resin composition for a honeycomb sandwich panel , wherein a mass ratio of the solid rubber to the liquid rubber (solid rubber / liquid rubber) is 1/1 to 1/5 .
2. 2. The epoxy resin composition for a honeycomb sandwich panel according to 1 above, wherein the content of the solid rubber is 3 to 15 parts by mass with respect to 100 parts by mass of the epoxy resin A.
3. The epoxy resin A includes a bifunctional or lower epoxy resin (a-1) and a trifunctional or higher functional epoxy resin (a-2),
The amount of the epoxy resin (a-1) is 20-80 parts by mass in 100 parts by mass of the epoxy resin A, and the amount of the epoxy resin (a-2) is 20-20 parts by mass in the epoxy resin A100. 3. The epoxy resin composition for honeycomb sandwich panels as described in 1 or 2 above, which is 80 parts by mass.
4). The epoxy resin composition for a honeycomb sandwich panel according to any one of the above 1 to 3, wherein the content of the liquid rubber is 1.5 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin A.
5. The epoxy resin composition for a honeycomb sandwich panel according to any one of the above 1 to 4, wherein the filler is at least one selected from the group consisting of fumed silica, carbon black, and carbon nanotubes.
6). The epoxy resin A includes an epoxy resin having a viscosity at room temperature of 5,000 mPa · s or less, and the amount thereof is 30 to 100 parts by mass in 100 parts by mass of the epoxy resin A,
The epoxy resin A includes an epoxy resin having a viscosity at room temperature exceeding 5,000 mPa · s, and the amount thereof is 0 to 70 parts by mass in 100 parts by mass of the epoxy resin A. Epoxy resin composition for honeycomb sandwich panels.
7). The epoxy resin (a-1) and / or the epoxy resin (a-2) contains an epoxy resin having a viscosity at room temperature of 5,000 mPa · s or less, and the amount is 30 in 100 parts by mass of the epoxy resin A100. ~ 100 parts by mass,
The epoxy resin (a-1) and / or the epoxy resin (a-2) contains an epoxy resin having a viscosity at room temperature exceeding 5,000 mPa · s, and the amount is 0 in 100 parts by mass of the epoxy resin A100. The epoxy resin composition for honeycomb sandwich panels according to any one of the above 3 to 6, which is ˜70 parts by mass.
8). The epoxy resin composition for a honeycomb sandwich panel according to any one of 1 to 7 above, wherein the amount of the filler is 0.5 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin A.
9. The epoxy resin composition for a honeycomb sandwich panel according to any one of the above 1 to 8, which contains substantially no solvent.
10. A master batch process for obtaining the rubber master batch by kneading at least the solid rubber and the liquid rubber;
A mixing step of mixing the rubber masterbatch, the epoxy resin A, the filler, and the curing agent to obtain the epoxy resin composition for a honeycomb sandwich panel according to any one of 1 to 9 above. A method for producing an epoxy resin composition for a honeycomb sandwich panel.
11. 11. The method for producing an epoxy resin composition for a honeycomb sandwich panel as described in 10 above, wherein substantially no solvent is used at least in the masterbatch step.
12 A prepreg for a honeycomb sandwich panel obtained by using the epoxy resin composition for a honeycomb sandwich panel according to any one of 1 to 9 above and a fiber substrate.
13. 13. The prepreg for a honeycomb sandwich panel as described in 12 above, wherein the fiber base material is carbon fiber having an elastic modulus of 230 GPa or more.
14 14. A honeycomb sandwich panel obtained by laminating and bonding the prepreg for honeycomb sandwich panel according to the above 12 or 13 and a honeycomb core.
15. 15. The honeycomb sandwich panel according to the above 14, wherein the honeycomb core is at least one selected from the group consisting of an aramid honeycomb, an aluminum honeycomb, a paper honeycomb, and a glass honeycomb.

The epoxy resin composition for a honeycomb sandwich panel of the present invention has high toughness, excellent mixing property between solid rubber and epoxy resin, suitable viscosity, and excellent workability (for example, impregnation into a fiber substrate).
The method for producing an epoxy resin composition for a honeycomb sandwich panel according to the present invention includes mixing properties and productivity of solid rubber and epoxy resin (for example, a solvent is not required and a removal step is not required, a general-purpose mixing device Can be easily manufactured), and gelation hardly occurs.
The prepreg for a honeycomb sandwich panel of the present invention is excellent in workability (for example, tack, drape) and provides a tough honeycomb sandwich panel.
The honeycomb sandwich panel of the present invention is tough.

FIG. 1 is a perspective view schematically showing an example of the honeycomb sandwich panel of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of a cross section obtained by cutting the honeycomb sandwich panel in parallel with the side surfaces of the prisms of the honeycomb core.

The present invention will be described in detail below.
The epoxy resin composition for honeycomb sandwich panels of the present invention is
Containing at least one epoxy resin A, a rubber masterbatch, a filler, and a curing agent;
The rubber master batch, a solid rubber having a functional group capable of reacting with the epoxy resin A, at least viewed contains a liquid rubber,
The functional group is a hydroxy group, an amino group, a carboxyl group (—COOH) or a glycidyl group;
A composition in which a mass ratio of the solid rubber to the liquid rubber (solid rubber / liquid rubber) is 1/1 to 1/5 .

The epoxy resin A will be described below.
The epoxy resin A contained in the epoxy resin composition for honeycomb sandwich panels of the present invention is not particularly limited as long as it is a compound having one or more epoxy groups. For example, a conventionally well-known thing is mentioned.

  The viewpoint that the epoxy resin A has higher toughness, is excellent in the mixing property of the solid rubber and the epoxy resin, has a more appropriate viscosity, is excellent in workability (for example, impregnation into a fiber base material), and is excellent in heat resistance. Therefore, the epoxy resin A preferably contains a bifunctional or lower functional epoxy resin (a-1) and a trifunctional or higher functional epoxy resin (a-2).

The epoxy resin (a-1) will be described below.
In the present invention, the epoxy resin (a-1) contained in the epoxy resin A is a compound having one or two epoxy groups in one molecule.

  Examples of the monoepoxy compound as the epoxy resin (a-1) include butyl glycidyl ether, phenyl glycidyl ether, alkylphenyl glycidyl ether, benzoic acid glycidyl ester, and styrene oxide.

  Examples of the bifunctional epoxy resin as the epoxy resin (a-1) include bisphenol A type, bisphenol F type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol S type, bisphenol AF type, and biphenyl type. Bifunctional glycidyl ether type epoxy resin such as epoxy compound having a bisphenyl group, polyalkylene glycol type, alkylene glycol type epoxy compound, epoxy compound having naphthalene ring, epoxy compound having fluorene group; or dimer acid And glycidyl ester type epoxy resins of synthetic fatty acids such as: rubber modified epoxy resins containing polybutadiene and acrylonitrile butadiene rubber (NBR).

  The epoxy resin (a-1) has higher toughness, is superior in the mixing property between the solid rubber and the epoxy resin, has a more appropriate viscosity, is excellent in workability (for example, impregnation into a fiber base material), and is heat resistant. From the viewpoint of excellent properties, low viscosity type bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, bisphenol F type epoxy resins and glycidyl ester type epoxy resins are preferred.

The epoxy resin (a-1) has higher toughness as a matrix of the composite material, is excellent in the mixing property of the solid rubber and the epoxy resin, is excellent in low viscosity for ensuring workability, and can be further secured in heat resistance. From the viewpoint, a form in which a mono-epoxy is added to a bifunctional epoxy resin mainly as necessary is desirable.
The bifunctional epoxy resin and monoepoxy can be used alone or in combination of two or more.

The epoxy resin (a-2) will be described below.
In the present invention, the epoxy resin (a-2) contained in the epoxy resin A is a compound having three or more epoxy groups in one molecule.
Examples of the epoxy resin (a-2) include tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl. Glycidylamine type epoxy resin such as diaminodiphenylmethane (TGDDM); aminophenol type epoxy resin such as triglycidyl-p-aminophenol and triglycidyl-p-aminocresol; phenol novolac type, orthocresol novolak type, trishydroxyphenyl Examples thereof include polyfunctional glycidyl ether type epoxy resins such as methane type and tetraphenylolethane type; glycidyl ester type epoxy resins of synthetic fatty acids such as dimer acid.

The viewpoint that the epoxy resin (a-2) has higher heat resistance, is excellent in the mixing property between the solid rubber and the epoxy resin, has a more appropriate viscosity, and is excellent in workability (for example, impregnation into a fiber base material). Therefore, a liquid or semi-solid epoxy resin is preferable.
An epoxy resin (a-2) can be used individually or in combination of 2 types or more, respectively.

  The amount of the epoxy resin (a-1) is higher in toughness, more excellent in the mixing property of the solid rubber and the epoxy resin, and low viscosity for ensuring good workability (for example, impregnation into a fiber base material). From the viewpoint of maintaining heat resistance and further ensuring heat resistance, the content is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass in 100 parts by mass of the epoxy resin A.

  The amount of the epoxy resin (a-2) is higher in toughness, more excellent in the mixing property between the solid rubber and the epoxy resin, and low viscosity for ensuring good workability (for example, impregnation into a fiber base material). From the viewpoint of maintaining heat resistance and further ensuring heat resistance, the content is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass in 100 parts by mass of the epoxy resin A.

Epoxy resin A is excellent in the mixing property of the solid rubber and the epoxy resin, and maintains a low viscosity for ensuring good workability (for example, impregnation into a fiber base material). It is desirable to contain an epoxy resin having a viscosity of 5,000 mPa · s or less.
The amount of the epoxy resin having a viscosity at room temperature of 5,000 mPa · s or less is superior to the mixing property of the solid rubber and the epoxy resin, and ensures good workability (for example, impregnation into a fiber base material). In order to maintain low viscosity, it is preferable that it is 30-100 mass parts (30-100 mass% in the epoxy resin A) in 100 mass parts of epoxy resin A, and it is more preferable that it is 40-70 mass parts.
Epoxy resin A has higher heat resistance, is superior in mixing properties of solid rubber and epoxy resin, has a more appropriate viscosity, and has excellent workability (for example, impregnation into a fiber substrate) at room temperature. It is preferable to contain an epoxy resin having a viscosity of more than 5,000 mPa · s.
The amount of the epoxy resin having a viscosity of more than 5,000 mPa · s at room temperature is higher in heat resistance, more excellent in the mixing property of the solid rubber and the epoxy resin, more suitable in viscosity, and workability (for example, fiber base material From the viewpoint of excellent impregnation into the resin, it is preferably 0 to 70 parts by mass, more preferably 30 to 60 parts by mass in 100 parts by mass of the epoxy resin A.
In the present invention, the viscosity of the epoxy resin is measured using an E-type viscometer under the condition of 25 ° C.

  An epoxy resin having a viscosity of 5,000 mPa · s or less at room temperature is superior in the mixing property between a solid rubber and an epoxy resin, and has a low viscosity for ensuring good workability (for example, impregnation into a fiber base material). From the viewpoint of maintaining the property, the viscosity is preferably 3000 mPa · s or less, and more preferably 2000 mPa · s or less.

Examples of the bifunctional or lower epoxy resin having a viscosity of 5,000 mPa · s or less include resorcinol type epoxy resins such as diglycidyl resorcinol; glycidyl ester type epoxy resins such as diglycidyl hexahydrophthalate and diglycidyl tetrahydrophthalate, Examples thereof include hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A type epoxy resin, and monoepoxy resin.
Examples of the trifunctional or higher functional epoxy resin having a viscosity of 5,000 mPa · s or less include glycidylamine such as tetraglycidyl-m-xylylenediamine and 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane. Type epoxy resin; aminophenol type epoxy resin such as triglycidyl-p-aminophenol, triglycidyl-p-aminocresol; hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A type epoxy resin .
Examples of the bifunctional or lower epoxy resin having a viscosity exceeding 5,000 mPa · s include rubber-modified epoxy resins containing polybutadiene and acrylonitrile butadiene rubber (NBR).
Examples of the trifunctional or higher functional epoxy resin having a viscosity exceeding 5,000 mPa · s include phenol novolac type epoxy resins.
Part or all of the epoxy resin (a-1) can be an epoxy resin having a viscosity of 5,000 mPa · s or less at room temperature. Part or all of the epoxy resin (a-1) can be an epoxy resin having a viscosity exceeding 5,000 mPa · s at room temperature. The same applies to the epoxy resin (a-2).

The epoxy resin (a-1) and / or the epoxy resin (a-2) is excellent in the mixing property between the solid rubber and the epoxy resin, and ensures good workability (for example, impregnation into a fiber base material). In order to maintain the low viscosity, it is preferable to include an epoxy resin having a viscosity at room temperature of 5,000 mPa · s or less.
Amount of epoxy resin (a-1) and / or epoxy resin (a-2) having a viscosity at room temperature of 5,000 mPa · s or less [in the case of epoxy resin (a-1) and epoxy resin (a-2) The total amount of these. The same applies below. ] Is excellent in the mixing property between the solid rubber and the epoxy resin, and maintains low viscosity for ensuring good workability (for example, impregnation into a fiber base material). It is preferable that it is 30-100 mass parts, and it is more preferable that it is 40-70 mass parts.

The epoxy resin (a-1) and / or the epoxy resin (a-2) has higher heat resistance, is excellent in the mixing property between the solid rubber and the epoxy resin, has a more appropriate viscosity, and has workability (for example, fiber base). From the standpoint of excellent impregnation into the material, it is preferable to include an epoxy resin having a viscosity at room temperature exceeding 5,000 mPa · s.
The amount of the epoxy resin (a-1) and / or the epoxy resin (a-2) whose viscosity at room temperature exceeds 5,000 mPa · s is higher in heat resistance and depends on the mixing property between the solid rubber and the epoxy resin. From the viewpoint that it is excellent and the viscosity is more appropriate and the workability (for example, the impregnation property to the fiber base material) is excellent, it is preferably 0 to 70 parts by mass in 100 parts by mass of the epoxy resin A, and 30 to 60 More preferred is part by mass.

The rubber master batch will be described below.
The rubber master batch contained in the epoxy resin for honeycomb sandwich panels of the present invention includes at least a solid rubber having a functional group capable of reacting with the epoxy resin A and a liquid rubber.
In the present invention, solid rubber refers to rubber that is solid at room temperature (23 ° C.). Liquid rubber refers to rubber that is liquid at room temperature (23 ° C.).

The solid rubber contained in the rubber masterbatch is a rubber having a functional group that can react with the epoxy resin A.
Examples of the functional group capable of reacting with the epoxy resin A include a hydroxy group, an amino group, a carboxyl group (—COOH), and a glycidyl group .
Among these, a rubber containing a carboxyl group is particularly preferable from the viewpoint that the effect of improving toughness is higher and the mixing property with the epoxy resin is excellent.
It is preferable that the functional group ratio which 1 molecule of solid rubber has is 6 mass% or less from a viewpoint of the gelatinization suppression in a compound with an epoxy resin.

The rubber as the skeleton of the solid rubber is not particularly limited. Examples thereof include acrylonitrile butadiene rubber and hydrogenated products thereof, acrylic rubber, ethylene-acrylic rubber, epichlorohydrin rubber, ethylene-vinyl acetate rubber and the like.
Among them, the skeleton of the solid rubber is preferably acrylonitrile butadiene rubber (NBR) from the viewpoint that the effect of improving toughness is higher and the mixing property between the solid rubber and the epoxy resin is excellent. From the viewpoint that the solid rubber has a higher toughness-improving effect and is excellent in the mixing property between the solid rubber and the epoxy resin, a carboxy-containing acrylonitrile butadiene rubber is preferable.

  Examples of preferable carboxy-containing acrylonitrile butadiene rubber include Nipol 1072 and DN631 manufactured by Nippon Zeon Co., Ltd.

The molecular weight of the solid rubber is preferably 100,000 or more. When the molecular weight is in such a range, the effect of improving toughness is more excellent. In the present invention, the molecular weight of the solid rubber is a weight average molecular weight expressed in terms of polystyrene by gel permeation chromatography (GPC).
The solid rubbers can be used alone or in combination of two or more.

  The content of the solid rubber is excellent in toughness-improving effect, more excellent in mixing with the epoxy resin, and from the viewpoint of maintaining the workability of the resin after compounding (for example, impregnation into the fiber base material), 100 parts by mass of the epoxy resin A It is preferable that it is 3-15 mass parts with respect to it, and it is more preferable that it is 5-10 mass parts.

The liquid rubber will be described below.
The liquid rubber contained in the rubber master batch is not particularly limited.
One preferred embodiment of the liquid rubber is that it has a functional group capable of reacting with the epoxy resin A in view of being excellent in the mixing property between the solid rubber and the epoxy resin and also having an effect of improving toughness.
The functional group capable of reacting with the epoxy resin A is not particularly limited as long as it can react with the epoxy group. For example, a hydroxy group, an amino group, a carboxyl group, a glycidyl group, etc. are mentioned.
Especially, the rubber | gum containing a carboxyl group or a glycidyl group is especially preferable from a viewpoint that the toughness improvement effect is higher and it is excellent in a mixing property with an epoxy resin.

The rubber as the skeleton of the liquid rubber is not particularly limited. Examples thereof include acrylonitrile butadiene rubber and hydrogenated products thereof, acrylic rubber, ethylene-acrylic rubber, epichlorohydrin rubber, ethylene-vinyl acetate rubber and the like.
Among these, liquid rubber is preferably terminal carboxyl-modified butadiene-acrylonitrile rubber (CTBN) or epoxy-modified butadiene-acrylonitrile rubber from the viewpoint that the effect of improving toughness is higher and the mixing property between solid rubber and epoxy resin is excellent.

The molecular weight of the liquid rubber is preferably 1,000 or more. When the molecular weight is within such a range, it is preferable from the viewpoint that the mixing property of the solid rubber and the epoxy resin is excellent, the viscosity is more appropriate, and the workability (for example, the impregnation property to the fiber base material) is excellent. In the present invention, the molecular weight of the liquid rubber is a weight average molecular weight expressed in terms of polystyrene by gel permeation chromatography (GPC).
The liquid rubbers can be used alone or in combination of two or more.

  The content of the liquid rubber is 1.5 to 30 mass with respect to 100 mass parts of the epoxy resin A from the viewpoint of ensuring the mixing property and workability of the solid rubber and the epoxy resin (for example, the impregnation property to the fiber base material). Part is preferable, and 5 to 20 parts by mass is more preferable.

Mass ratio of solid rubber to liquid rubber (solid rubber / liquid rubber) is excellent in toughness improvement, excellent in mixability with epoxy resin, and workability of resin after compounding (for example, impregnation into fiber substrate) from the viewpoint of maintaining, 1 / 1-1 / 5 der is, and more preferably 1 / 1-1 / 3.

  In the present invention, the rubber master batch includes at least a solid rubber and a liquid rubber. The rubber master batch may further contain a part or all of the epoxy resin A or a part or all of the filler as required.

The filler will be described below.
The filler contained in the epoxy resin composition for honeycomb sandwich panels of the present invention is not particularly limited as long as it is contained in the epoxy resin composition. For example, an inorganic filler and an organic filler are mentioned. In view of superior heat resistance, an inorganic filler is preferred.
Examples of the inorganic filler include carbon black, silica (for example, fumed silica, wet silica), carbon nanotube, silica sand, calcium silicate, mica, talc, alumina, montmorillonite, aluminum nitride, boron nitride, calcium carbonate, and oxidation. Titanium is mentioned.

Among these, at least one selected from the group consisting of fumed silica, carbon black, and carbon nanotubes from the viewpoint of excellent mixing with an epoxy resin and excellent control of resin flow at the time of honeycomb panel production due to thixotropy. Preferably there is.
The fillers can be used alone or in combination of two or more.

  The amount of the filler is superior to the mixing property with the epoxy resin, the viscosity is more appropriate, and from the viewpoint of ensuring workability (for example, the impregnation property to the fiber base material), the amount of the filler is 0. The amount is preferably 5 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass.

The curing agent will be described below.
The hardening | curing agent contained in the epoxy resin composition for honeycomb sandwich panels of this invention will not be restrict | limited especially if it can be used with respect to an epoxy resin.
Examples of curing agents include 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, imidazole compounds, amine compounds such as tetramethylguanidine; thiourea-added amines; polyamides; polyols; polymercaptans; Carboxylic acid; acid anhydride; carboxylic acid hydrazide; carboxylic acid amide; polyphenol compound; novolac resin; latent curing agent (for example, ketimine, dicyandiamide).
The curing agents can be used alone or in combination of two or more.

  The amount of the curing agent is 0.5 to 1. with respect to the epoxy resin A from the viewpoint of balancing the toughness of the cured resin, heat resistance, and other mechanical properties, and sufficiently securing the pot life of the prepreg. It is preferably 2 equivalents, and more preferably 0.6 to 1.1 equivalents.

The epoxy resin composition for a honeycomb sandwich panel according to the present invention is preferably one that is substantially free of a solvent from the viewpoint of minimizing the content of volatile components that may become defects when the prepreg is cured. Can be mentioned.
In the present invention, “substantially not containing a solvent” means that the amount of the solvent is 0.5% by mass or less based on the total amount of the epoxy resin composition for a honeycomb sandwich panel of the present invention.

The epoxy resin composition for a honeycomb sandwich panel of the present invention is necessary as long as the effects of the epoxy resin composition for a honeycomb sandwich panel of the present invention are not impaired, in addition to the epoxy resin A, rubber master batch, filler, and curing agent. Depending on the case, additives can be included.
Additives include, for example, thermoplastic resins, curing catalysts such as boron trifluoride / amine salt catalysts, anti-aging agents, flame retardants, reaction retarders, antioxidants, pigments (dyes), plasticizers, thixotropic agents Examples thereof include an imparting agent, an ultraviolet absorber, a surfactant (including a leveling agent), a dispersing agent, a dehydrating agent, an adhesion imparting agent, and an antistatic agent.

  The manufacturing method of the epoxy resin composition for honeycomb sandwich panels of the present invention will be described in the following manufacturing method of the epoxy resin composition for honeycomb sandwich panels of the present invention.

  The epoxy resin composition for a honeycomb sandwich panel of the present invention is, for example, a two-component type having a first liquid containing a rubber master batch, an epoxy resin A and a filler, and a second liquid containing a curing agent. it can. The additive can be added to one or both of the first liquid and the second liquid.

  The epoxy resin composition for honeycomb sandwich panels of the present invention can be cured by heat. The temperature for curing the epoxy resin composition for honeycomb sandwich panels of the present invention is preferably 160 to 200 ° C.

Using the cured product obtained after curing the epoxy resin composition for honeycomb sandwich panels of the present invention, the fracture toughness value measured according to ASTM-D5045-99 is higher toughness, peel strength [for example From the viewpoint that the peel strength after self-adhesion between the face plate such as a prepreg and other members (for example, honeycomb core) can be increased, 1.8 MPa · m ^1/2 or more is preferable. 0 MPa · m ^1/2 or more is more preferable.

The epoxy resin composition for a honeycomb sandwich panel of the present invention has a minimum viscosity of 1 to 100 Pa · s, preferably 5 to 40 Pa · s, as measured by dynamic viscoelasticity at a heating rate of 2 ° C./min. Is more preferable. When making the minimum viscosity of a dynamic viscoelasticity measurement into said range, it is preferable when expressing the productivity and self-adhesiveness of a prepreg. In the case of 1 Pa · s or more, a good fillet can be formed, and self-adhesiveness is improved. In the case of 100 Pa · s or less, the fiber base material can be easily impregnated with the resin composition at the time of prepreg production while maintaining fillet formability.
In the present invention, the minimum viscosity by dynamic viscoelasticity measurement is the temperature of 25 ° C. to 200 ° C. with a temperature increase rate of 2 ° C./min, using the epoxy resin composition for honeycomb sandwich panels of the present invention as a sample. The minimum value of the complex viscosity in the dynamic viscoelasticity measurement with a frequency of 10 rad / sec and a strain of 1% shall be said.

The epoxy resin composition for honeycomb sandwich panels of the present invention has a viscosity at 40 ° C. of 5,000 Pa · s or less as measured by dynamic viscoelasticity at a temperature rising rate of 2 ° C./min. From the viewpoint of excellent coating workability.
In the present invention, the viscosity at 40 ° C. by dynamic viscoelasticity measurement is a temperature between 25 ° C. and 200 ° C. and a temperature increase rate of 2 ° C. using the epoxy resin composition for honeycomb sandwich panels of the present invention as a sample. The value at 40 ° C. of the complex viscosity in the dynamic viscoelasticity measurement with a frequency of 10 min / min, a frequency of 10 rad / sec, and a strain of 1%.

  Applications of the epoxy resin composition for honeycomb sandwich panels of the present invention include, for example, matrix resins for prepregs used in honeycomb sandwich panel panels, adhesives, primers, sealing materials, casting materials, sealants, paints, etc. Is mentioned.

  The adherend to which the epoxy resin composition for a honeycomb sandwich panel of the present invention can be used is not particularly limited. Examples thereof include fiber base materials such as carbon fiber, glass fiber, and aramid fiber, plastic, rubber, glass, ceramic, concrete, mortar, aluminum alloy, titanium alloy, stainless alloy, and steel.

The manufacturing method of the epoxy resin composition for honeycomb sandwich panels of the present invention will be described below.
The method for producing an epoxy resin composition for a honeycomb sandwich panel of the present invention,
A master batch process for obtaining the rubber master batch by kneading at least the solid rubber and the liquid rubber;
It is a manufacturing method which has the mixing process of mixing the said rubber masterbatch, the said epoxy resin A, the said filler, and the said hardening | curing agent, and obtaining the epoxy resin composition for honeycomb sandwich panels of this invention.
The method for producing an epoxy resin composition for a honeycomb sandwich panel of the present invention may be hereinafter referred to as “the production method of the present invention”.

  The production method of the present invention has a masterbatch step, so that the mixing property and productivity of solid rubber and epoxy resin (for example, no need for using a solvent and no removal step, general-purpose mixing device) Can be easily manufactured), and the temperature rise in the mixing step is suppressed, and the composition is hardly gelled.

The master batch process will be described below.
The master batch forming step of the production method of the present invention is a step of obtaining the rubber master batch by kneading at least the solid rubber and the liquid rubber.

The solid rubber and liquid rubber used in the master batch process are as defined above.
The kneading apparatus used in the master batch process is not particularly limited as long as it is used for rubber kneading. For example, a kneader and a roll (biaxial roll etc.) are mentioned.

In the master batch process, at least the solid rubber and the liquid rubber are kneaded. Moreover, part or all of the epoxy resin A or part or all of the filler can be further kneaded together with solid rubber and liquid rubber as necessary in the masterbatch step.
One preferred embodiment is that substantially no solvent is used in the masterbatch step. The fact that the solvent is not practically used means that the amount of the solvent is 0 to 0.5% by mass in the total amount of the epoxy resin composition for honeycomb sandwich panels obtained by the production method of the present invention (the same applies hereinafter).
It is preferable that the temperature in a masterbatch process is 30-60 degreeC.

The mixing process will be described below.
The mixing step is a step of obtaining the epoxy resin composition for a honeycomb sandwich panel of the present invention by mixing the rubber master batch, the epoxy resin A, the filler, and the curing agent.

The epoxy resin A, the filler, and the curing agent used in the mixing step are as defined above.
The mixing apparatus used in the mixing step is not particularly limited as long as it is used for producing an epoxy resin composition. For example, a high torque type mixing apparatus (a Dalton type mixer, a planetary type mixer, etc.) is mentioned.

In the mixing step, the rubber master batch, the epoxy resin A, the filler, and the curing agent are mixed. When a part of the epoxy resin A is used in the master batch process, the remainder of the epoxy resin A is mixed. When a part of the filler is used in the master batch process, the remainder of the filler is mixed.
One preferred embodiment is that substantially no solvent is used in the mixing step. It is preferable that the temperature in a mixing process is 50-100 degreeC.

Next, the prepreg for the honeycomb sandwich panel of the present invention will be described below.
The prepreg for the honeycomb sandwich panel of the present invention is
It is obtained using the epoxy resin composition for honeycomb sandwich panels of the present invention and a fiber base material.

Specifically, the prepreg for a honeycomb sandwich panel of the present invention is obtained by impregnating a fiber substrate with an epoxy resin composition for a honeycomb sandwich panel.
The matrix composition used in the prepreg for the honeycomb sandwich panel of the present invention is not particularly limited as long as it is an epoxy resin composition for the honeycomb sandwich panel of the present invention.
The prepreg for the honeycomb sandwich panel of the present invention can provide a tough honeycomb sandwich panel with excellent workability (for example, tack and drape) by using the epoxy resin for the honeycomb sandwich panel of the present invention as a matrix resin.

  The fiber substrate used for the prepreg for the honeycomb sandwich panel of the present invention is not particularly limited, and examples thereof include conventionally known ones. Especially, it is preferable that it is at least 1 sort (s) chosen from the group which consists of carbon fiber, glass fiber, and an aramid fiber from a viewpoint of intensity | strength and an elasticity modulus, and it is more preferable that it is carbon fiber. Examples of aramid fibers include Kevlar.

The form of the fiber is not particularly limited, and examples thereof include woven fabric, roving, non-woven fabric, knitted fabric, and tulle. The optimum value of the basis weight of the fiber varies depending on the form and use, but for example, in the case of a carbon fiber fabric, it is preferably 150 to 400 g / m ² .

  Examples of commercially available fibers include carbon fibers T-300 and T-700 manufactured by Toray Industries, Inc. and carbon fibers HTA and UT-500 manufactured by Toho Rayon.

  The elastic modulus of the fiber base material is preferably 230 GPa or more from the viewpoint of excellent rigidity and strength of the molded product and weight reduction. The fiber base material is preferably a carbon fiber having an elastic modulus of 230 GPa or more.

  The manufacturing method of the prepreg for the honeycomb sandwich panel of the present invention is not particularly limited. For example, either a wet method using a solvent or a hot melt method which is a solventless method can be employed. From the viewpoint of not using a solvent, the hot melt method is preferable.

In the case of the hot melt method, the epoxy resin composition for the honeycomb sandwich panel to be used is formed into a film on a release paper in advance by a film coater, the fiber base material is sandwiched from above and below by this film, and heated to enter the base material. Impregnate with resin.
The temperature at which the matrix resin is heated varies depending on the curing agent to be used, but is preferably 80 to 120 ° C. from the viewpoint of ensuring workability (tack, drape) of the prepreg after impregnation.

When the prepreg for the honeycomb sandwich panel of the present invention is produced by the wet method, the epoxy resin composition for the honeycomb sandwich panel is dissolved in a solvent to prepare a varnish and then impregnated.
Examples of the solvent used in preparing the varnish include alcohols such as methanol, ethanol and propanol; ketones such as methyl ethyl ketone (MEK).
From the viewpoint that the drying time can be shortened, the amount of the solvent used is preferably 80 to 200 parts by mass with respect to 100 parts by mass of the solid content of the epoxy resin composition for honeycomb sandwich panels.

  The optimum range of the matrix resin content in the prepreg for the honeycomb sandwich panel of the present invention varies depending on the specific gravity of the fiber used, but it has excellent workability (eg, tack, drape), excellent appearance after curing, and heat resistance. From the viewpoint of excellent mechanical properties, it is preferably 30 to 60% by mass in the prepreg.

  The method for using the prepreg for the honeycomb sandwich panel of the present invention is not particularly limited. For example, a method of thermosetting the prepreg for a honeycomb sandwich panel of the present invention as it is and a method of semi-curing and further curing the prepreg for a honeycomb sandwich panel of the present invention can be mentioned. Although the temperature at the time of curing varies depending on the curing agent to be used, it is preferable that the final curing temperature is 160 to 200 ° C., particularly in applications requiring heat resistance.

  The prepreg for a honeycomb sandwich panel of the present invention can be used for a surface plate of a honeycomb sandwich panel. A honeycomb sandwich panel can be produced by laminating the prepreg for a honeycomb sandwich panel of the present invention with a honeycomb core, heat curing, and bonding.

  Moreover, the prepreg for a honeycomb sandwich panel of the present invention can be used for a fiber reinforced composite material other than for a surface plate of a honeycomb sandwich panel. For example, aircraft parts such as fairing, flap, leading edge, floor panel, propeller, fuselage; motorcycle parts such as motorcycle frames, cowls, fenders; doors, bonnets, tailgates, side fenders, side panels, fenders, energy absorbing members Automobile parts such as trunk lid, hard top, side mirror cover, spoiler, diffuser, ski carrier, engine cylinder cover, engine hood, chassis, air spoiler, propeller shaft; top vehicle nose, roof, side panel, door, bogie cover, Vehicle outer panels such as side skirts; Railway vehicle parts such as luggage racks and seats; Interior, wing inner panels, outer panels, roofs, floors, etc. Aero parts such as side skirts to be installed; Cases such as notebook PCs and mobile phones; Medical uses such as X-ray cassettes and top boards; Applications for acoustic products such as flat speaker panels and speaker cones; Golf heads, face plates, snowboards Sports equipment applications such as surfboards, protectors, etc .; general industrial applications such as leaf springs, windmill blades, elevators (籠 panels, doors).

Next, the honeycomb sandwich panel of the present invention will be described below.
The honeycomb sandwich panel of the present invention is
It is obtained by laminating and bonding the prepreg for the honeycomb sandwich panel of the present invention and the honeycomb core.

  The prepreg used in the honeycomb sandwich panel of the present invention is not particularly limited as long as it is a prepreg for the honeycomb sandwich panel of the present invention. The prepreg for a honeycomb sandwich panel of the present invention has excellent adhesiveness because it forms a fillet having high strength, and a tough honeycomb panel can be obtained without using an adhesive between the prepreg and the honeycomb core. .

  The honeycomb core used in the honeycomb sandwich panel of the present invention is not particularly limited. Examples thereof include at least one selected from the group consisting of an aramid honeycomb, an aluminum honeycomb, a paper honeycomb, and a glass honeycomb.

  The size of the hexagonal column of the honeycomb core honeycomb structure is not particularly limited, and from the viewpoint of strength and weight reduction, the honeycomb core preferably has a cell size length of 1/8 to 3/8 inch.

The honeycomb sandwich panel of the present invention is not particularly limited for its production.
An example of a method for manufacturing a honeycomb sandwich panel of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a perspective view schematically showing an example of the honeycomb sandwich panel of the present invention.
FIG. 2 is a cross-sectional view schematically showing an example of a cross section obtained by cutting the honeycomb sandwich panel in parallel with the side surfaces of the prisms of the honeycomb core. Part a of FIG. 2 is a honeycomb sandwich panel to which a prepreg formed from a conventional resin composition for a prepreg sheet is bonded. Part b of FIG. 2 is an example of the honeycomb sandwich panel of the present invention.

  In FIG. 1, a honeycomb sandwich panel 1 is obtained by bonding a honeycomb sandwich panel prepreg 10 and a honeycomb core 11. More specifically, the honeycomb sandwich panel 1 is formed by laminating a honeycomb sandwich panel prepreg 10 formed of the honeycomb sandwich panel epoxy resin composition of the present invention on one or both of the end portions 12 of the honeycomb core 11 having a honeycomb structure. And it can produce by heat-hardening and making it adhere | attach with an autoclave etc., crimping | bonding from both ends.

In FIG. 2, when a prepreg using a conventional composition as an epoxy resin composition for a honeycomb sandwich panel is used, as shown in part a of FIG. Are all pressed down to the lower surface portion 13 ′ and no fillet is formed on the upper surface portion 13, or the prepreg 10 for the honeycomb sandwich panel and the honeycomb core 11 are partially formed. There may be a gap (not shown) on the adhesive surface.
On the other hand, when the epoxy resin composition for a honeycomb sandwich panel of the present invention is used, the prepreg 10 for the honeycomb sandwich panel and the honeycomb core 11 are completely bonded as shown in FIG. Therefore, an appropriate amount of the composition can be present in the prepreg without causing the epoxy resin composition for the honeycomb sandwich panel to flow out too much and the resin component to disappear from the prepreg.
Accordingly, the upper fillet 14 can complete curing while maintaining an appropriate shape. Further, when the viscosity once decreases on the lower surface, the lower fillet 14 ′ is formed by the surface tension, and the epoxy resin composition for the honeycomb sandwich panel is appropriately held to complete the curing.

  From the viewpoint of heat resistance of the cured product, the heating temperature for bonding the honeycomb sandwich panel prepreg 10 and the honeycomb core 11 is preferably 160 to 200 ° C, and more preferably 170 to 190 ° C.

The curing conditions for bonding the honeycomb sandwich panel prepreg 10 and the honeycomb core 11 are 2 to 5 ° C./min and the pressure is 2.5 to 4.0 kg / cm ² , and the temperature is increased to 160 to 185 ° C. One preferred embodiment is a method in which the temperature is maintained at 160 to 185 ° C. for 1 to 2 hours and then lowered to room temperature at 2 to 5 ° C./min.
By such a method, the honeycomb sandwich panel of the present invention can be manufactured.

The honeycomb sandwich panel of the present invention is tough and excellent in fillet formation, fillet strength, mechanical strength, and workability.
The honeycomb sandwich panel of the present invention can be used as a structural material for aircraft and automobiles, for example.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
<Evaluation>
About each composition obtained as follows, viscosity (minimum viscosity, 40 ° C. viscosity), prepreg adhesion (index of resin toughness) (climbing drum peel strength: CDP), impregnation property, The prepreg workability was evaluated. The results are shown in Table 1.

1. Viscosity (minimum viscosity, 40 ° C viscosity)
Each epoxy resin composition obtained as described below was used as a sample, and the temperature was 25 ° C. to 200 ° C., the rate of temperature increase was 2 ° C./min, the frequency was 10 rad / sec, and the strain was 1%. The lowest value of the complex viscosity in the viscoelasticity measurement and the viscosity at 40 ° C. were measured.

2. Prepreg workability Each epoxy resin composition obtained as described below was made into a resin film having a basis weight of 64 g / m ² at 60 ° C. with a film coater, and the obtained film was made into a fiber substrate (T manufactured by Toray Industries, Inc.) A plain woven fabric of 300-3000, a carbon fiber having a basis weight of 193 g / m ² and an elastic modulus of 230 GPa was placed on both sides and heat impregnated at 100 ° C. to obtain a prepreg having a resin content of 40%.
Two sheets of the obtained prepreg were bonded together at 23 ° C. to prepare samples for evaluation. The evaluation standard for tack is “strong tack” if it is a level where one prepreg cannot be peeled off again from the tack evaluation sample, and if two prepregs can be sufficiently attached and then peeled off. If the level is “medium tack” or two prepregs are not attached, “tack failure” was set.
The obtained prepreg was laminated on a chamfered honeycomb core to prepare a drape evaluation sample. The evaluation standard for drape is `` good drape '' when the prepreg of the sample for drape evaluation has no wrinkles and the prepreg can be laminated on the honeycomb core, and `` bad drape '' when the prepreg does not conform to the chamfer shape and wrinkles remain. It was.
In the evaluation of the prepreg workability, when the prepreg could not be produced because the resin viscosity was too high or gelation occurred due to heating on the coater, “prepreg production impossible” was set.

3. Pre-preg adhesion (climbing drum peel strength: CDP)
(1) Production of Honeycomb Sandwich Panel Two prepregs obtained as described above were laminated, and this was formed into a honeycomb core (Nomex Honeycomb (Aramid Honeycomb) SAH-1 / 8-8.0 manufactured by Showa Aircraft Industry Co., Ltd., thickness 12.7mm), placed in a vacuum bag, placed in a vacuum bag, and heated and cured in an autoclave at a temperature of 180 ° C for 2 hours (heating rate of 2.8 ° C / min) to produce a honeycomb sandwich panel did. During this time, the inside of the autoclave was pressurized to 0.32 MPa with compressed air.

(2) Climbing drum peel test (CDP: Climbing Drum Peel Test)
Using the obtained honeycomb sandwich panel, in accordance with ASTM D1781-98, it was cut into a predetermined size to obtain a test piece, and the upper side (Bag side: the surface in contact with the vacuum bag) and the lower side (Tool side: The peel strength (climbing drum peel strength, lb-in / 3 in) at a temperature of 23 ° C. (dry state) was measured for each of the face plates arranged on the surface in contact with the forming jig). The average value of the peel strength on the upper side of the honeycomb core and the peel strength on the lower side of the honeycomb core is calculated, and the obtained average value is shown in Table 1 as the climbing drum peel strength. When the average value is 15 [lb-in / 3 in] or more, it can be said that the climbing drum peel strength is high.

4). Impregnation A cross section of a honeycomb panel prepared for a climbing drum peeling test was polished and observed with an optical microscope having a magnification of 50 times.
The evaluation standard for impregnation is that the resin is sufficiently impregnated to the inside of the fiber as a result of observation, and if there are no defects such as voids or resin defects, the impregnation is "◎", and if there is a defect, the impregnation is "○". When significant defects were observed, the impregnation property was “x”.

<Production of composition>
Using the components shown in Table 1 in the amounts shown in the same table (unit: parts by mass), a composition was produced by the following method.
1. When there is a masterbatch process First, in the masterbatch process, solid rubber and liquid rubber are put into a biaxial roll and kneaded for 30 minutes under the condition of 50 ° C. Then, the total amount of filler and epoxy resin ( Half of a-1-1) was added and kneaded for 30 minutes to produce a rubber masterbatch.
Next, in the mixing step, the rubber master batch, the remainder of the epoxy resin A, and the curing agent are put into a planetary type mixing apparatus, and these are mixed for 1 hour under the condition of 70 ° C. to produce each epoxy resin composition. did.

2. In the case without the master batch process The components shown in Table 1 were put into a planetary mixer, and these were mixed at 70 ° C. for 2 hours to produce each epoxy resin composition.

Details of each component shown in Table 1 are as shown in Table 2 below. In Table 2, the unit of epoxy equivalent is g / equivalent.

As is apparent from the results shown in Table 1, Comparative Example 1 containing no filler had a low adhesive strength because of low toughness. In Comparative Example 2, which did not contain a rubber masterbatch and contained a solid rubber, the composition gelled during the production of the composition, and a prepreg could not be produced. Comparative Example 3, which does not contain a rubber masterbatch and contains a thermoplastic resin instead, becomes a hard and difficult-to-handle resin composition as can be seen from the high viscosity of the composition at 40 ° C. In addition, the tack and drape when used as a prepreg were also poor.
On the other hand, the compositions of Examples 1 to 4 have high adhesive strength, excellent mixing properties between the solid rubber and the epoxy resin, appropriate viscosity, and workability (for example, impregnation into a fiber base material). It was an epoxy resin composition for honeycomb sandwich panels that was excellent and hardly gelled.
Moreover, according to the manufacturing method of the epoxy resin composition of Examples 1-4, the mixing property of solid rubber and an epoxy resin, productivity (for example, it is not necessary to use a solvent and a removal step is unnecessary, It was possible to produce an epoxy resin composition for a honeycomb sandwich panel that is excellent in that it can be easily produced by a mixing device of the above and is less likely to be gelled.
The prepregs of Examples 1 to 4 became honeycomb sandwich panel prepregs that were excellent in workability (e.g., tack, drape) and provided a tough honeycomb sandwich panel.
The honeycomb sandwich panels of Examples 1 to 4 were tough.

As described above, the liquid rubber is used for securing the workability to make a master batch, so that a dedicated kneading apparatus is not required, and the final resin can be mixed with a general-purpose mixing facility.
Moreover, it became possible to express the toughness equivalent to engineering plastic addition amount 45-60 weight part in the case of solid rubber addition amount 6-8 mass parts (with respect to 100 mass parts epoxy resin).
Further, by utilizing the effect of the filler (filler), it is not necessary to maintain the minimum viscosity of the resin higher than necessary, and matrix mixing at a level that does not sacrifice workability is possible.
The matrix resin used in the present invention has low viscosity in the work area (100 ° C. or lower), and not only the workability at the time of prepreg production, but also the workability (tack, drape) after prepreg engineering Greatly superior to plastic compounding systems. Further, molding defects (voids) at the time of curing hardly occur.

DESCRIPTION OF SYMBOLS 1 Honeycomb sandwich panel 10 Prepreg for honeycomb sandwich panel 11 Honeycomb core 12 End 13 Upper surface 13 'Lower surface 14 Upper fillet 14' Lower fillet a Conventional honeycomb sandwich panel b Honeycomb sandwich panel of the present invention c Cell size

Claims (15)

Containing at least one epoxy resin A, a rubber masterbatch, a filler, and a curing agent;
The rubber master batch, a solid rubber having a functional group capable of reacting with the epoxy resin A, at least viewed contains a liquid rubber,
The functional group is a hydroxy group, an amino group, a carboxyl group (—COOH) or a glycidyl group;
An epoxy resin composition for a honeycomb sandwich panel , wherein a mass ratio of the solid rubber to the liquid rubber (solid rubber / liquid rubber) is 1/1 to 1/5 .   The epoxy resin composition for a honeycomb sandwich panel according to claim 1, wherein a content of the solid rubber is 3 to 15 parts by mass with respect to 100 parts by mass of the epoxy resin A. The epoxy resin A includes a bifunctional or lower epoxy resin (a-1) and a trifunctional or higher functional epoxy resin (a-2),
The amount of the epoxy resin (a-1) is 20-80 parts by mass in 100 parts by mass of the epoxy resin A, and the amount of the epoxy resin (a-2) is 20-20 parts by mass in the epoxy resin A100. The epoxy resin composition for a honeycomb sandwich panel according to claim 1 or 2, wherein the epoxy resin composition is 80 parts by mass.   The epoxy resin composition for a honeycomb sandwich panel according to any one of claims 1 to 3, wherein a content of the liquid rubber is 1.5 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin A.   The epoxy resin composition for a honeycomb sandwich panel according to any one of claims 1 to 4, wherein the filler is at least one selected from the group consisting of fumed silica, carbon black, and carbon nanotubes. The epoxy resin A includes an epoxy resin having a viscosity at room temperature of 5,000 mPa · s or less, and the amount thereof is 30 to 100 parts by mass in 100 parts by mass of the epoxy resin A,
The said epoxy resin A contains the epoxy resin in which the viscosity in room temperature exceeds 5,000 mPa * s, The quantity is 0-70 mass parts in 100 mass parts of said epoxy resins A, The any one of Claims 1-5 The epoxy resin composition for honeycomb sandwich panels as described. The epoxy resin (a-1) and / or the epoxy resin (a-2) contains an epoxy resin having a viscosity at room temperature of 5,000 mPa · s or less, and the amount is 30 in 100 parts by mass of the epoxy resin A100. ~ 100 parts by mass,
The epoxy resin (a-1) and / or the epoxy resin (a-2) contains an epoxy resin having a viscosity at room temperature exceeding 5,000 mPa · s, and the amount is 0 in 100 parts by mass of the epoxy resin A100. It is -70 mass parts The epoxy resin composition for honeycomb sandwich panels in any one of Claims 3-6.   The epoxy resin composition for a honeycomb sandwich panel according to any one of claims 1 to 7, wherein an amount of the filler is 0.5 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin A.   The epoxy resin composition for honeycomb sandwich panels according to any one of claims 1 to 8, which contains substantially no solvent. A master batch process for obtaining the rubber master batch by kneading at least the solid rubber and the liquid rubber;
A mixing step of mixing the rubber master batch, the epoxy resin A, the filler, and the curing agent to obtain the epoxy resin composition for a honeycomb sandwich panel according to any one of claims 1 to 9. A method for producing an epoxy resin composition for a honeycomb sandwich panel.   The method for producing an epoxy resin composition for a honeycomb sandwich panel according to claim 10, wherein substantially no solvent is used at least in the masterbatch step.   A prepreg for a honeycomb sandwich panel obtained by using the epoxy resin composition for a honeycomb sandwich panel according to any one of claims 1 to 9 and a fiber substrate.   The prepreg for a honeycomb sandwich panel according to claim 12, wherein the fiber base material is carbon fiber having an elastic modulus of 230 GPa or more.   A honeycomb sandwich panel obtained by laminating and bonding the prepreg for a honeycomb sandwich panel according to claim 12 or 13 and a honeycomb core.   The honeycomb sandwich panel according to claim 14, wherein the honeycomb core is at least one selected from the group consisting of an aramid honeycomb, an aluminum honeycomb, a paper honeycomb, and a glass honeycomb.

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