JP4972864B2 - Process for producing resin composition for self-adhesive prepreg - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a resin composition for self-adhesive type prepreg holding compressive strength and tensile strength of the prepreg in a well-balanced state and improving the peel strength between the prepreg and a honeycomb core when applied to a honeycomb panel. <P>SOLUTION: The method for production comprises a first staging step of polymerizing a plurality of kinds of epoxy resin compositions and a second staging step of mixing the resultant epoxy resin composition obtained in the first staging step with a new another epoxy resin composition and a curing agent and carrying out polymerization. The epoxy resin composition obtained in the second staging step is mixed with a new epoxy resin, a solid rubber and the curing agent to afford the final composition. In the process, the compounding ratio of the solid rubber is &ge;10 pts.wt. based on 100 pts.wt. of the epoxy resin in the final composition. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a method for producing a resin composition for a self-adhesive prepreg, and more specifically, when the compressive strength and tensile strength of a prepreg are maintained in a well-balanced state by optimizing the minimum viscosity of the resin and applied to a honeycomb panel. The present invention relates to a method for producing a resin composition for a self-adhesive prepreg, which improves the fluidity of a honeycomb core to improve the peel strength between the honeycomb core and the honeycomb core.

  A prepreg (fiber reinforced composite material) as a molding material obtained by dissolving a matrix resin in a solvent and mixing a curing agent or additive and impregnating cloth, mat, roving, etc. is an aircraft and automobile due to its excellent mechanical properties. Widely used in industrial applications such as

  In particular, honeycomb panels having prepregs as face plates are widely used for aircraft structural materials from the viewpoint of weight reduction. In general, a honeycomb panel is manufactured by adhering a prepreg to both surfaces of a honeycomb core made of a material such as paper, aluminum, aramid, and glass.

  Conventionally, in order to bond a honeycomb core and a prepreg, a film-like adhesive is sandwiched between the honeycomb core and the prepreg and heated to simultaneously cure the prepreg itself and bond the prepreg and the honeycomb core. Has been generally adopted. However, in recent years, from the viewpoint of reducing the weight of the honeycomb core and reducing the molding cost, the honeycomb panel can be used without using a film-like adhesive by imparting the same properties as the adhesive to the resin used in the prepreg. Research has been conducted on molding (see, for example, Patent Documents 1 and 2).

However, it has the same properties (especially peel strength) as conventional film-like adhesives, and it can satisfy the physical properties (especially tensile strength and compressive strength at high temperature) as the face plate of the honeycomb panel. At present, the development of a resin composition for an adhesive prepreg has not yet been developed.
JP 58-82755 A JP 2001-323046 A

  An object of the present invention is to solve such a conventional problem, and to maintain a good balance between the compressive strength and tensile strength of the prepreg and to improve the peel strength with the honeycomb core when applied to a honeycomb panel. It is providing the manufacturing method of the resin composition for adhesion type prepregs.

Method for producing a self-adhesive prepreg resin composition of the present invention for achieving the above object, a first stearyl polymerizing more epoxy resins - and managing step, said first stearyl - obtained by managing step Managing process and, said second stearate - - new epoxy resin obtained epoxy resins by managing step, a second stearyl for epoxy resins to be polymerized by mixing different epoxy resin Abura及 beauty hardener new A method for producing a resin composition for a self-adhesive prepreg in which a solid rubber comprising an acrylonitrile-butadiene copolymer having a carboxyl group or an amino group and a curing agent are mixed to obtain a final composition, the blending ratio of the solid rubber Is 10 parts by weight or more with respect to 100 parts by weight of the epoxy resin in the final composition.

According to the present invention, the epoxy resins of the polymerization process as well as in two stages, thereby acrylonitrile having a carboxyl group or an amino group of the new epoxy resins and an amount in the resulting epoxy resins - butadiene copolymer The final viscosity of the epoxy resin composition obtained as the final composition is optimized to maintain the compressive strength and tensile strength of the prepreg in a well-balanced manner. When applied to a panel, the fluidity to the honeycomb core is improved, and the honeycomb wall is sufficiently wetted to form a good fillet, whereby the peel strength between the prepreg and the honeycomb core can be improved. Moreover, as a method for producing the epoxy resin composition, no special process is added, and therefore workability is not lowered.

  The configuration of the present invention will be described in detail below.

The method for producing a self-adhesive prepreg resin composition of the invention, the first stearyl polymerizing more epoxy resins - and managing step, the first stearyl - new epoxy resins obtained by managing step second stearyl polymerizing a mixture of different epoxy resin Abura及 beauty curing agent - with a new epoxy resin obtained epoxy resins by managing step, a carboxyl group or an amino group - and managing step, the second stearate When mixing the solid rubber made of acrylonitrile-butadiene copolymer and the curing agent to obtain the final composition, the blending ratio of the solid rubber is preferably 10 parts by weight or more with respect to 100 parts by weight of the epoxy resin in the final composition, preferably Is 12 parts by weight or more.

As a result, the final viscosity of the epoxy resin composition as the final composition is optimized, and the compressive strength and tensile strength of the prepreg are maintained in a well-balanced manner, and the fluidity to the honeycomb core when applied to a honeycomb panel is good. Thus, the honeycomb wall is sufficiently wetted to form a good fillet, whereby the peel strength between the prepreg and the honeycomb core can be improved. In addition, since the epoxy resin manufacturing method does not add any special process, workability is not deteriorated.

  As the epoxy resin, amine resins, phenols, and epoxy resins having a compound having a carbon-carbon double bond as a precursor are preferably used. Examples of the epoxy resin having an amine as a precursor include various isomers of tetraglycidyldiaminodiphenylmethane, triglycidyl p-aminophenol, and triglycidylaminocresol. Among these, tetraglycidyldiaminodiphenylmethane is preferably used as a resin composition for a prepreg used for a face plate of an aircraft honeycomb panel because it is excellent in heat resistance.

Further, phenol - is the Le acids with epoxy resins to be derived from a precursor, bisphenol - Le A type epoxy resins, bisphenol - Le F type epoxy resins, bisphenol - Le S type epoxy resins, phenol novolak type epoxy resin, cresol A novolac type epoxy resin, a resorcinol type epoxy resin, etc. are mentioned.

  Further, examples of the epoxy resin having a compound having a carbon-carbon double bond as a precursor include a biphenyl type epoxy resin, a dicyclopentadiene type epoxy resin, and the like. In particular, an epoxy resin having a naphthalene skeleton has water absorption resistance and Since it is excellent in heat resistance, it is preferably used as a resin composition for a prepreg used for a face plate of an aircraft honeycomb panel.

  In this invention, the epoxy resin used as the base material of the resin composition for prepreg may be appropriately mixed with a plurality of types of epoxy resins selected from the various epoxy resins described above. Preferably, a bifunctional epoxy resin and a trifunctional or higher polyfunctional epoxy resin may be blended. Thereby, it can be set as the epoxy resin which has the fluidity | liquidity of resin, and the heat resistance after hardening.

The solid rubber added after managing step, from the viewpoint of compatibility with the epoxy resin, a random copolymer of butadiene and acrylonitrile - - Second stearate in the present invention is that acrylonitrile - butadiene copolymer is used. Further, the solid rubber having a functional group to enhance the adhesion to the epoxy resin is used. As the functional group, a carboxyl group or an amino group is used, and in particular, a solid acrylonitrile-butadiene rubber containing a carboxyl group is preferably used. As a result, the minimum viscosity of the epoxy resin composition as the final composition can be increased to ensure toughness and prevent adhesiveness while preventing excessive resin outflow during molding. Furthermore, the compressive strength and tensile strength of the prepreg can be improved with a better balance.

  The curing agent used in the present invention is not particularly limited as long as it is a compound having an active group capable of reacting with an epoxy group. Preferably, a compound having an amino group, an acid anhydride group, or an azide group is suitable. More specifically, dicyandiamide, diaminodiphenylmethane, various isomers of diaminodiphenylsulfone, aminobenzoic acid esters, various acid anhydrides, phenol novolac resin, cresol novolac resin, polyphenol compound, and the like can be mentioned.

As described above, the manufacturing method of the self-adhesive type prepreg resin composition of the present invention, the epoxy resins of the polymerization process as well as in two stages, thereby resulting new epoxy resins and Tokoro epoxy resins The final composition is obtained by adding a fixed amount of acrylonitrile-butadiene copolymer solid rubber having a carboxyl group or amino group , and the final viscosity of the epoxy resin composition obtained as the final composition is optimized. In addition to maintaining a good balance between the compressive strength and tensile strength of the prepreg, and forming a good fillet on the honeycomb wall when applied to a honeycomb panel, the peel strength between the prepreg and the honeycomb core is improved. It is preferably used as a face plate for a honeycomb panel.

As shown in Table 1, the epoxy resin composition (Example 1) according to the present invention consisting of the “final composition” shown in the middle part of the table with different compositions, weights and polymerization steps constituting the epoxy resin as shown in Table 1 and the comparative epoxy resin While producing the composition (Comparative Examples 1-4), 5 types of prepregs were produced by the method shown below using each epoxy resin composition . Note that Comparative Example 4 does not include a step of polymerizing an epoxy resin.

[Preparation of prepreg]
Each resin composition was applied onto a release paper using a reverse roll coater to prepare a resin film having a resin basis weight of 65 g / m ² . Next, the two resin films were superposed on both sides of a plain weave carbon fiber (T300-3K, manufactured by Toray Industries, Inc.) and heated and pressed to impregnate the carbon fiber with the resin composition. After impregnating the resin composition, the resin film was peeled off, and a polyethylene film was placed on one side of the peeled surface and wound up to obtain a prepreg sheet.

  The minimum viscosity of the five types of resin compositions described above is measured by the following method, and the prepreg impregnated with these five types of resin compositions is measured for porous compressive strength, plane tensile strength and peel strength by the following test methods. Measurements were made and the results are shown in Table 1.

[Minimum viscosity]
Using a dynamic viscoelastic device (ARES-II) manufactured by Rheometrix Co., with a parallel plate method (diameter 25.4 mm), the heating rate is 2.8 ° C./min, the frequency is 10 rad / sec, and the strain is 1 %, The minimum viscosity (Pa · s) of each resin composition was measured, and the results are shown in Table 1.

[Perforated compressive strength]
Sixteen prepregs made of each resin composition are stacked and placed in a bag, which is heated and cured in an autoclave at 180 ° C. for 2 hours (heating rate: 2.8 ° C./min). A plate was made. During this time, the inside of the autoclave was pressurized to 0.32 MPa with compressed air.

  The obtained molded plate was processed into a predetermined size to produce each test piece, and the test conditions were (1) dry state at 23 ° C. and (2) 93 ° C. The perforated compressive strength (MPa) of each test piece in the moisture absorption state was measured. In addition, as each test piece in a hygroscopic state, the test piece taken out after being immersed in warm water of 70 ° C. for 2 weeks was used.

[Plane tensile strength]
The molded plate used in the measurement of the above [Perforated compressive strength] is processed into predetermined dimensions to produce each test piece, and each test at 23 ° C. (dry state) according to MIL-STD-401. The plane tensile strength (MPa) of the piece was measured.

[Peel strength]
Two prepregs made of the respective resin compositions were laminated, placed on both sides of a honeycomb core (Nomex SAH-1 / 8-8.0, manufactured by Showa Aircraft Industry Co., Ltd.), and then placed in a bag. This was heated in an autoclave at 180 ° C. for 2 hours (heating rate: 2.8 ° C./min) and cured to prepare a honeycomb panel. During this time, the inside of the autoclave was pressurized to 0.32 MPa with compressed air.

The obtained honeycomb panel was processed into a predetermined size, and the peel strength (lb-in / 3 in) of each test piece at 23 ° C. (dry state) was measured in accordance with ASTM D1781.

From the property evaluation results in Table 1, the epoxy resin composition of Example 1 was subjected to a two-stage staging process and the blending ratio of the solid rubber was increased. As a result, it was higher than the minimum viscosity of Comparative Examples 1 to 4. It was confirmed that the prepreg had a high peel strength when applied to a honeycomb panel and an excellent self-adhesive property, while exhibiting a viscosity and having the same porous compressive strength and flat tensile strength.

Claims (1)

First stearyl polymerizing more epoxy resins - and managing step, said first stearyl - first polymerizing a mixture of different epoxy resin Abura及 beauty hardener newly obtained epoxy resins by managing step two stearyl - mixing consists butadiene copolymer solid rubber and the curing agent - and managing step, said second stearyl - new epoxy resin obtained epoxy resins by managing step, acrylonitrile having a carboxyl group or an amino group A method for producing a resin composition for a self-adhesive prepreg to obtain a final composition,
The manufacturing method of the resin composition for self-adhesive type prepregs which makes the compounding ratio of the said solid rubber 10 weight part or more with respect to 100 weight part of epoxy resins in the said final composition.