U.S. patent application number 14/348423 was filed with the patent office on 2014-11-20 for fiber-reinforced resin composite material and method for producing same.
This patent application is currently assigned to JX NIPPON OIL & ENERGY CORPORATION. The applicant listed for this patent is Yoshihiro Fukuda, Hiroyasu Ihara, Naoyuki Sekine, Eikatsu Yamaguchi. Invention is credited to Yoshihiro Fukuda, Hiroyasu Ihara, Naoyuki Sekine, Eikatsu Yamaguchi.
Application Number | 20140343191 14/348423 |
Document ID | / |
Family ID | 47994555 |
Filed Date | 2014-11-20 |
United States Patent
Application |
20140343191 |
Kind Code |
A1 |
Sekine; Naoyuki ; et
al. |
November 20, 2014 |
FIBER-REINFORCED RESIN COMPOSITE MATERIAL AND METHOD FOR PRODUCING
SAME
Abstract
The purpose of the present invention is to inhibit a decrease in
strength attribute to the interface between a simple-shape portion
and a complicated-shape portion. This fiber-reinforced resin
composite material comprises: a simple-shape portion formed from at
least one sheet-shaped prepreg material obtained by impregnating
reinforcing fibers with a resin; and a complicated-shape portion
obtained by impregnating reinforcing fibers with a resin, the
complicated-shape portion having been integrated with the
simple-shape portion. The resin used for the preprg material
comprised the same components as the resin used for the
complicated-shape portion.
Inventors: |
Sekine; Naoyuki;
(Shinjuku-ku, JP) ; Yamaguchi; Eikatsu;
(Shinjuku-ku, JP) ; Fukuda; Yoshihiro;
(Yokohama-shi, JP) ; Ihara; Hiroyasu;
(Yokohama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sekine; Naoyuki
Yamaguchi; Eikatsu
Fukuda; Yoshihiro
Ihara; Hiroyasu |
Shinjuku-ku
Shinjuku-ku
Yokohama-shi
Yokohama-shi |
|
JP
JP
JP
JP |
|
|
Assignee: |
JX NIPPON OIL & ENERGY
CORPORATION
Tokyo
JP
FUJI JUKOGYO KABUSHIKI KAISHA
Tokyo
JP
|
Family ID: |
47994555 |
Appl. No.: |
14/348423 |
Filed: |
September 30, 2011 |
PCT Filed: |
September 30, 2011 |
PCT NO: |
PCT/JP2011/072628 |
371 Date: |
March 28, 2014 |
Current U.S.
Class: |
523/400 |
Current CPC
Class: |
B32B 2605/08 20130101;
B32B 2605/18 20130101; C08J 2363/00 20130101; B32B 2260/046
20130101; B32B 2260/021 20130101; B32B 5/28 20130101; B29C 70/46
20130101; B32B 2605/00 20130101; B32B 2260/023 20130101; B32B
2250/20 20130101; B32B 3/02 20130101; B32B 27/12 20130101; B32B
2605/12 20130101; B32B 5/22 20130101; C08J 5/24 20130101; C08L
63/00 20130101; B29C 64/106 20170801; B32B 5/26 20130101; C08L
79/04 20130101; B32B 5/24 20130101; B32B 27/28 20130101; B29D
99/0014 20130101; B32B 2250/40 20130101; B32B 2250/02 20130101;
B29C 70/48 20130101; B32B 2605/10 20130101; B32B 27/04 20130101;
C08L 63/00 20130101; C08L 79/04 20130101 |
Class at
Publication: |
523/400 |
International
Class: |
C08L 79/04 20060101
C08L079/04; C08L 63/00 20060101 C08L063/00 |
Claims
1. A fiber-reinforced resin composite material comprising: a
simple-shape portion formed of at least one sheet of a prepreg
material composed of a reinforcing fiber impregnated with a resin;
and a complex-shape portion formed of a reinforcing fiber
impregnated with a resin, the complex-shape portion being
integrally formed with the simple-shape portion, wherein the resin
used in the prepreg material and the resin used in the
complex-shape portion comprise a same component(s).
2. The fiber-reinforced resin composite material of claim 1,
wherein the resin used in the prepreg material and the resin used
in the complex-shape portion are a benzoxazine resin
composition.
3. The fiber-reinforced resin composite material of claim 2,
wherein the benzoxazine resin composition comprises a compound
containing in its molecule a benzoxazine ring represented by a
formula (1), an epoxy resin, a curing agent and a toughness
enhancing agent: ##STR00006## wherein R.sub.1 represents a chain
alkyl group of 1 to 12 carbons, a ring alkyl group of 3 to 8
carbons, a phenyl group or a phenyl group substituted with a chain
alkyl group of 1 to 12 carbons or a halogen; and a hydrogen atom is
bonded to at least one of carbon atoms at an ortho position and a
para position of a carbon atom that bonds the oxygen atom of the
aromatic ring in the formula.
4. A method for producing a fiber-reinforced resin composite
material, comprising: forming a simple-shape portion from at least
one sheet of a prepreg material formed of a reinforcing fiber
impregnated with a resin; and forming a complex-shape portion
integrally with the simple-shape portion, the complex-shape portion
being formed of a reinforcing fiber impregnated with a resin,
wherein the resin used in the prepreg material and the resin used
in the complex-shape portion comprise a same component(s).
5. The method for producing the fiber-reinforced resin composite
material of claim 4, wherein the resin used in the prepreg material
and the resin used in the complex-shape portion are a benzoxazine
resin composition.
6. The method for producing the fiber-reinforced resin composite
material of claim 5, wherein the benzoxazine resin composition
comprises a compound containing in its molecule a benzoxazine ring
represented by a formula (1), an epoxy resin, a curing agent and a
toughness enhancing agent: ##STR00007## wherein R.sub.1 represents
a chain alkyl group of 1 to 12 carbons, a ring alkyl group of 3 to
8 carbons, a phenyl group or a phenyl group substituted with a
chain alkyl group of 1 to 12 carbons or a halogen; and a hydrogen
atom is bonded to at least one of carbon atoms of the aromatic ring
at an ortho position and a para position relative to the carbon
atom that bonds the oxygen atom in the formula.
Description
TECHNICAL FIELD
[0001] The present invention relates to a fiber-reinforced resin
composite material and a method for producing the same, and
specifically, relates to a fiber-reinforced resin composite
material used for structural members of aircrafts, land vehicles,
watercrafts and the like and a method for producing the same.
BACKGROUND ART
[0002] A fiber-reinforced resin composite material (FRP: Fiber
Reinforced Plastics) has been widely used as a fiber-reinforced
resin composite material used for structural members of aircrafts,
land vehicles, watercrafts and the like. Such a fiber-reinforced
resin composite material include, as a simple-shape portion, an
outer panel formed of a sheet(s) of a prepreg material(s) formed of
a carbon fiber(s) impregnated with a resin(s), and as a
complex-shape portion, a reinforcing portion formed of a
fiber-reinforced resin(s) such as a beam (girder), rib, longeron
and the like or a supporting member formed of a fiber-reinforced
resin (s) such as a bracket or both, which reinforcing portion and
supporting member are integrally provided on the interior side of
the outer panel.
[0003] To efficiently integrate such a simple-shape portion and
complex-shape portion, a technique to form a fiber-reinforced resin
composite material by Vacuum-assisted Resin Transfer Molding
(VaRTM) has been developed in recent years (see Non-Patent Document
1, for example).
PRIOR ART DOCUMENT
Non-Patent Document
[0004] Non-patent document 1: Shunsuke Kashiwagi, "Hybrid Seikei
CFRP no Soukan Tokusei Hyouka (Evaluation of Interlaminar
Properties of CFRP formed by Hybrid Molding)", Proceeding of 1st
Joint Conference of Composite Materials in Japan, the Society of
Materials Science, Japan, and Japan Society for Composite
Materials, March 2010, p. 426-429
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0005] When a fiber-reinforced resin composite material is formed
by the above method, a phase boundary is then formed at the joint
face of a simple-shape portion and a complex-shape portion. When
such a phase boundary is formed, the phase boundary may decrease
the strength of a fiber-reinforced resin composite material.
[0006] Thus, an object is the present invention is to suppress such
a decrease in the strength due to the presence of a phase boundary
of a simple-shape portion and a complex-shape portion.
Means for Solving Problem
[0007] The invention of claim 1 is a fiber-reinforced resin
composite material, including:
[0008] a simple-shape portion formed of at least one sheet of a
prepreg material composed of a reinforcing fiber impregnated with a
resin; and
[0009] a complex-shape portion formed of a reinforcing fiber
impregnated with a resin, the complex-shape portion being
integrally formed with the simple-shape portion, wherein
[0010] the resin used in the prepreg material and the resin used in
the complex-shape portion include a same component(s).
[0011] The invention of claim 2 is the fiber-reinforced resin
composite material of claim 1, wherein the resin used in the
prepreg material and the resin used in the complex-shape portion
are a benzoxazine resin composition.
[0012] The invention of claim 3 is the fiber-reinforced resin
composite material of claim 2, wherein the benzoxazine resin
composition includes a compound containing in its molecule a
benzoxazine ring represented by a formula (1), an epoxy resin, a
curing agent and a toughness enhancing agent:
##STR00001##
[0013] wherein R.sub.1 represents a chain alkyl group of 1 to 12
carbons, a ring alkyl group of 3 to 8 carbons, a phenyl group or a
phenyl group substituted with a chain alkyl group of 1 to 12
carbons or a halogen; and a hydrogen atom is bonded to at least one
of carbon atoms at an ortho position and a para position of a
carbon atom that bonds the oxygen atom of the aromatic ring in the
formula.
[0014] The invention of claim 4 is a method for producing a
fiber-reinforced resin composite material, the method
including:
[0015] forming a simple-shape portion from at least one sheet of a
prepreg material formed of a reinforcing fiber impregnated with a
resin; and
[0016] forming a complex-shape portion integrally with the
simple-shape portion, the complex-shape portion being formed of a
reinforcing fiber impregnated with a resin, wherein
[0017] the resin used in the prepreg material and the resin used in
the complex-shape portion include a same component(s).
[0018] The invention of claim 5 is the method of claim 4, wherein
the resin used in the prepreg material and the resin used in the
complex-shape portion are a benzoxazine resin composition.
[0019] The invention of claim 6 is the method of claim 5, wherein
the benzoxazine resin composition includes a compound containing in
its molecule a benzoxazine ring represented by a formula (1), an
epoxy resin, a curing agent and a toughness enhancing agent:
##STR00002##
[0020] wherein R.sub.1 represents a chain alkyl group of 1 to 12
carbons, a ring alkyl group of 3 to 8 carbons, a phenyl group or a
phenyl group substituted with a chain alkyl group of 1 to 12
carbons or a halogen; and a hydrogen atom is bonded to at least one
of carbon atoms at an ortho position and a para position of a
carbon atom that bonds the oxygen atom of the aromatic ring in the
formula.
Effect of the Invention
[0021] The inventors have focused attention on the fact that
properties required for a resin conventionally used in a prepreg
and properties required for a resin conventionally used in a
complex-shape portion (resins for RTM) are different, and when the
component(s) of a resin used in a simple-shape portion differ from
the component(s) of a resin used in a complex-shape portion, a
phase boundary is formed at their joint face in the case of using
that prior art, i.e., Vacuum-assisted Resin Transfer Molding. The
present inventors then have revealed that when a resin used in a
simple-shape portion and a resin used in a complex-shape portion
include (or are composed of) the same component(s), a phase
boundary is not formed at their joint face after the integration
and thus the decrease in strength can be suppressed. Hence,
according to the present invention, it is able to suppress the
decrease in strength caused due to a phase boundary of a
simple-shape portion and a complex-shape portion.
BRIEF DESCRIPTION OF DRAWING
[0022] FIG. 1 This is a schematic perspective view illustrating a
schematic configuration of a fiber-reinforced resin composite
material according to an embodiment of the present invention.
[0023] FIG. 2 This is an explanatory diagram illustrating steps for
forming a reinforcing portion of the fiber-reinforced composite
material illustrated in FIG. 1.
[0024] FIG. 3 This is an explanatory diagram illustrating the
conditions for a step of integrating the reinforcing portion as one
of steps for forming the fiber-reinforced composite material
illustrated in FIG. 1.
[0025] FIG. 4 This is a graph showing interlaminar shear strengths
of Example and Comparative Examples
[0026] FIG. 5 This is a graph showing four-point flexural strengths
of Example and Comparative Examples
EMBODIMENT FOR CARRYING OUT THE INVENTION
[0027] Preferred embodiments for carrying out the present invention
will now be described with reference to the drawings. The following
embodiments include various specifications that are technically
preferable for carrying out the present invention, but it is not
intended to restrict the scope of the present invention to the
following embodiments and illustrations.
[0028] FIG. 1 is a schematic perspective view illustrating a
schematic configuration of a fiber-reinforced resin composite
material according to an embodiment of the present invention. As
illustrated in FIG. 1, a fiber-reinforced resin composite material
1 includes an outer panel 2 as a simple-shape portion and a
reinforcing portion 3 as a complex-shape portion monolithically
integrated with the outer panel 2.
[0029] The outer panel 2 is formed by laminating multiple sheets of
a prepreg material 4. The prepreg material 4 is formed by
impregnating a reinforcing fiber with a resin.
[0030] The reinforcing portion 3 includes a base portion 31 which
is to be fixed on the outer panel 2 and a rib 32 which rises up
from the middle of the base portion 31. Similar to the above, the
reinforcing portion 3 is formed by impregnating a reinforced fiber
with a resin. The resin used in the prepreg material 4 constituting
the outer panel 2 and the resin used in the reinforcing portion 3
are composed of the same component(s).
[0031] The resin used in the prepreg material 4 and the reinforcing
portion 3 will be now described.
[0032] This resin is a benzoxazine resin composition that contains
a compound (A) containing in its molecule a benzoxazine ring(s)
represented by the formula (1); an epoxy resin (B); a curing agent
(C); and a toughness enhancing agent (D).
[0033] The compound (A) is a benzoxazine resin represented by the
formula (1). In the formula (1), R.sub.1 represents a chain alkyl
group of 1 to 12 carbons, a ring alkyl group of 3 to 8 carbons, a
phenyl group, or a phenyl group substituted with a halogen(s) or a
chain alkyl group(s) of 1 to 12 carbons.
[0034] Examples of the chain alkyl group of 1 to 12 carbons include
methyl group, ethyl group, propyl group, isopropyl group, n-butyl
group, isobutyl group and t-butyl group.
[0035] Examples of the ring alkyl group of 3 to 8 carbons include
cyclopentyl group and cyclohexyl group.
[0036] Examples of the phenyl group substituted with a halogen(s)
or a chain alkyl group(s) of 1 to 12 carbons include phenyl group,
o-methyl phenyl group, m-methyl phenyl group, p-methyl phenyl
group, o-ethyl phenyl group, m-ethyl phenyl group, p-ethyl phenyl
group, o-t-butyl phenyl group, m-t-butyl phenyl group, p-t-butyl
phenyl group, o-chloro phenyl group and o-bromo phenyl group.
[0037] Among the above examples, R.sub.1 is preferably methyl
group, ethyl group, propyl group, phenyl group or o-methyl phenyl
group because these groups provide good handleability.
[0038] Preferable examples of the benzoxazine resin that is the
compound (A) include monomers represented by the following
formulae, oligomers of several molecules of any of these monomers,
reactants of a compound(s) containing a benzoxazine ring(s) whose
structures are different from those of these monomers with at least
one of these monomers.
##STR00003## ##STR00004## ##STR00005##
[0039] The compound (A) is excellent in fire retardancy because the
compound (A) contains a skeleton similar to that of a phenol resin,
which skeleton is obtained by ring-opening polymerization of
benzoxazine rings. Further, the compound (A) provides excellent
mechanical properties such as low water absorption and high elastic
modulus because the compound (A) has a dense structure.
[0040] The epoxy resin (B) is a component that controls viscosity
of a composition and enhances curability of a composition.
Preferable examples of the epoxy resin (B) include epoxy resins
whose precursors are, for example, amines, phenols, carboxylic
acids and unsaturated carbons.
[0041] Examples of epoxy resins whose precursors are amines include
tetraglycidylaminodiphenylmethane, glycidyl compounds of
xylenediamine, triglycidylaminophenol, regioisomers of
glycidylaniline and glycidylaniline substituted with an alkyl
group(s) or a halogen(s) or both.
[0042] Commercially available liquid products below are described
with their viscosities each of which is the product's complex
viscoelastic modulus .eta.* at 25.degree. C. obtained using a
dynamic viscoelasticity measuring device described later.
[0043] Examples of commercially available products of
tetraglycidylaminodiphenylmethane include SUMI-EPDXY (registered
trademark, hereinafter the same shall apply in this) ELM434
(manufactured by Sumitomo Chemical Co., Ltd.); Araldite (registered
trademark, hereinafter the same shall apply in this) MY720,
Araldite MY 721, AralditeMY9512, Araldite MY9612, Araldite MY9634
and Araldite MY9663 (manufactured by Huntsman Advanced Materials);
and jER (registered trademark, hereinafter the same shall apply in
this) 604 (manufactured by Mitsubishi Chemical Corporation).
[0044] Examples of commercially available products of
triglycidylaminophenol include jER 630 (viscosity: 750 mPas)
(manufactured by Mitsubishi Chemical Corporation); Araldite MY0500
(viscosity: 3500 mPas) and MY0510 (viscosity: 600 mPas)
(manufactured by Huntsman Advanced Materials); and ELM100
(viscosity: 16000 mPas) (manufactured by Sumitomo Chemical Co.,
Ltd.).
[0045] Examples of commercially available products of
glycidylanilines include GAN (viscosity: 120 mPas) and GOT
(viscosity: 60 mPas) (manufactured by NIPPON KAYAKU Co., Ltd.).
[0046] Examples of glycidyl ether epoxy resins whose precursors are
phenols include bisphenol A epoxy resins, bisphenol F epoxy resins,
bisphenol S epoxy resins, epoxy resins containing biphenyl
skeletons, phenol novolac epoxy resins, cresol novolac epoxy
resins, resorcinol epoxy resins, epoxy resins containing
naphthalene skeletons, trisphenylmethane epoxy resins, phenol
aralkyl epoxy resins, dicyclopentadiene epoxy resins,
diphenylfluorene epoxy resins, various isomers of them and alkyl-
or halogen-substituted derivatives of them.
[0047] In addition, urethane- and isocyanate-modified epoxy resins
whose precursors are phenols are also examples of glycidyl ether
epoxy resins.
[0048] Examples of commercially available products of liquid
bisphenol A epoxy resins include jER 825 (viscosity: 5000 mPas),
jER 826 (viscosity: 8000 mPas), jER 827 (viscosity: 10000 mPas) and
jER 828 (viscosity: 13000 mPas) (manufactured by Mitsubishi
Chemical Corporation); EPICLON (registered trademark, hereinafter
the same shall apply in this) 850 (viscosity: 13000 mPas)
(manufactured by DIC Corporation); EPOTOHTO (registered trademark,
hereinafter the same shall apply in this) YD-128 (viscosity: 13000
mPas) (manufactured by Nippon Steel Chemical Co., Ltd.); and
DER-331 (viscosity: 13000 mPas) and DER-332 (viscosity: 5000 mPas)
(manufactured by The Dow Chemical Co.).
[0049] Examples of commercially available products of solid or
semisolid bisphenol A epoxy resins include jER 834, jER 1001, jER
1002, jER 1003, jER 1004, jER 1004AF, jER 1007 and jER 1009
(manufactured by Mitsubishi Chemical Corporation).
[0050] Examples of commercially available products of liquid
bisphenol F epoxy resins include jER 806 (viscosity: 2000 mPas),
jER 807 (viscosity: 3500 mPas), jER 1750 (viscosity: 1300 mPas),
jER (manufactured by Mitsubishi Chemical Corporation); EPICLON 830
(viscosity: 3500 mPas) (manufactured by DIC Corporation); and
EPOTOHTO YD-170 (viscosity: 3500 mPas) and EPOTOHTO YD-175
(viscosity: 3500 mPas) (manufactured by Nippon Steel Chemical Co.,
Ltd.).
[0051] Examples of commercially available products of solid
bisphenol F epoxy resins include 4004P, jER 4007P and jER 4009P
(manufactured by Mitsubishi Chemical Corporation); and EPOTOHTO
YDF2001 and EPOTOHTO YDF2004 (manufactured by Nippon Steel Chemical
Co., Ltd.).
[0052] Examples of bisphenol S epoxy resins include EXA-1515
(manufactured by DIC Corporation).
[0053] Examples of commercially available products of epoxy resins
containing biphenyl skeletons include jER YX4000H, jER YX4000 and
jER YL6616 (manufactured by Mitsubishi Chemical Corporation); and
NC-3000 (manufactured by NIPPON KAYAKU Co., Ltd.).
[0054] Examples of commercially available products of phenol
novolac epoxy resins include jER 152 and jER 154 (manufactured by
Mitsubishi Chemical Corporation); and EPICLON N-740, EPICLON N-770
and EPICLON N-775 (manufactured by DIC Corporation).
[0055] Examples of commercially available products of cresol
novolac epoxy resins include EPICLON N-660, EPICLON N-665, EPICLON
N-670, EPICLON N-673 and EPICLON N-695 (manufactured by DIC
Corporation); and EOCN-1020, EOCN-1025 and EOCN-1045 (manufactured
by NIPPON KAYAKU Co., Ltd.).
[0056] Examples of commercially available products of resorcinol
epoxy resins include DENACOL (registered trademark, hereinafter the
same shall apply in this) EX-201 (viscosity: 250 mPas)
(manufactured by Nagase ChemteX Corporation).
[0057] Examples of commercially available products of epoxy resins
containing naphthalene skeletons include EPICLON HP4032
(manufactured by DIC Corporation); and NC-7000 and NC-7300
(manufactured by NIPPON KAYAKU Co., Ltd.).
[0058] Examples of commercially available products of
trisphenylmethane epoxy resins include TMH-574 (manufactured by
Sumitomo Chemical Co., Ltd.).
[0059] Examples of commercially available products of
dicyclopentadiene epoxy resins include EPICLON HP7200, EPICLON
HP7200L and EPICLON HP7200H (manufactured by DIC Corporation);
Tactix (registered trademark) 558 (manufactured by Huntsman
Advanced Materials); and XD-1000-1L and XD-1000-2L (manufactured by
NIPPON KAYAKU Co., Ltd.).
[0060] Examples of commercially available products of urethane- and
isocyanate-modified epoxy resins include AER4152 which contains
oxazolidone ring (manufactured by Asahi Kasei E-materials
Corporation).
[0061] Examples of epoxy resins whose precursors are carboxylic
acids include glycidyl compounds of phthalic acid, glycidyl
compounds of hexahydro phthalic acid, glycidyl esters of dimer
acids and their isomers.
[0062] Examples of commercially available products of diglycidyl
phthalates include EPOMIK (registered trademark, hereinafter the
same shall apply in this) R508 (viscosity: 4000 mPas) (manufactured
by Mitsui Chemical Corporation); and DENACOL EX-721 (viscosity: 980
mPas) (manufactured by Nagase ChemteX Corporation).
[0063] Examples of commercially available products of diglycidyl
phthalates include EPOMIK R540 (viscosity: 350 mPas) (manufactured
by Mitsui Chemical Corporation); and AK-601 (viscosity: 300 mPas)
(NIPPON KAYAKU CO., Ltd.).
[0064] Examples of commercially available products of diglycidyl
esters of dimer acids include jER 871 (viscosity: 650 mPas)
(manufactured by Mitsubishi Chemical Corporation); and EPOTOHTO
YD-171 (viscosity: 650 mPas) (manufactured by Nippon Steel Chemical
Co., Ltd.).
[0065] Examples of epoxy resins whose precursors are unsaturated
carbons include alicyclic epoxy resins; namely, as commercially
available products of (3',4'-epoxycyclohexane)
methyl-3,4-epoxycyclohexanecarboxylate, CELLOXIDE (registered
trademark, hereinafter the same shall apply in this) 2021P
(viscosity: 250 mPas) (manufactured by DAICEL CORPORATION) and
CY179 (viscosity: 400 mPas) (manufactured by Huntsman Advanced
Materials); as a commercially available product of
(3',4'-epoxycyclohexane) octyl-3,4-epoxycyclohexanecarboxylate,
CELLOXIDE 2081 (viscosity: 100 mPas) (manufactured by DAICEL
CORPORATION); and as a commercially available product of
1-methyl-4-(2-methyloxyranyl)-7-oxabicyclo[4.1.0] heptane,
CELLOXIDE 3000 (viscosity: 20 mPas) (manufactured by DAICEL
CHEMICAL INDUSTRIES, LTD.).
[0066] The epoxy resin (B) is contained preferably 10 to 100 parts
by mass, and more preferably 10 to 60 parts by mass per 100 parts
by mass of the compound (A) which is a benzoxazine resin. It is
better that the viscosity at 25.degree. C. of the epoxy resin that
is liquid at 25.degree. C. is lower in terms of tackiness and
drapeability. The viscosity is preferably 5 mPa or more and 20000
mPa or less; 5 mPa is the minimum in commercially available
products of epoxy resins. More preferably, the viscosity is 5 mPa
or more and 15000 mPa or less. When the viscosity is over 20000
mPa, tackiness and drapeability may decrease.
[0067] As the epoxy resins that are solid at 25.degree. C., epoxy
resins having a high content of an aromatic compound(s) are
preferable for increasing fire retardancy. For example, epoxy
resins containing biphenyl skeletons, epoxy resins containing
naphthalene skeletons and phenol aralkyl resins are given as
examples.
[0068] Preferable examples of the curing agent (C) include one of,
or a mixture of two or more of the followings: aromatic amines such
as diethyltoluenediamine, metaphenylenediamine,
diaminodiphenylmethane, diaminodiphenylsulfone, metaxylenediamine
and derivatives of them; aliphatic amines such as
triethylenetetramine and isophoronediamine; imidazole derivatives;
dicyandiamide; tetramethylguanidine; carboxylic acid anhydrides
such as methylhexahydrophthalate anhydride; carboxylic acid
anhydrides such as adipic acid anhydride; carboxylic amides;
monofunctional phenols; polyfunctional phenols such as bisphenol A;
polyphenols; polymercaptans; carboxylate salts; and Lewis acid-base
complexes such as boron trifluoride ethylamine complex. Among them,
one of, or a mixture of two or more of aromatic amines, sulfonate
esters, monofunctional phenols, polyfunctional phenols such as
bisphenol A and polyphenols are preferable.
[0069] The curing agent (C) such as exemplified above is reacted
with the compound (A) which is a benzoxazine and the epoxy resin
(B), and then a resin composition or fiber-reinforced composite
material excellent in heat resistance and moisture resistance can
be obtained.
[0070] The curing agent (C) is contained preferably 5 to 30 parts
by mass, and more preferably 7 to 25 parts by mass per 100 parts by
mass of the sum of the compound (A) and the epoxy resin (B). When
it is less than 5 parts by mass, the extent of cure of the resin
composition as a whole may be insufficient because curing reaction
is difficult to progress; when it is over 30 parts by mass,
mechanical properties such as glass transition temperature of the
cured product may deteriorate.
[0071] The toughness enhancing agent (D) is categorized in to an
agent to be dispersed as organic or inorganic fine particles in a
resin composition and an agent to be dissolved as a liquid resin or
a resin monomer in a resin composition. Some of the dispersing-type
agents, however, are partially dissolved in a resin composition,
and in turn, some of the dissolving-type agents partially remain
undissolved as fine particles due to polymerization or other
reasons. Both types can be used.
[0072] For example, reactive elastomers, Hycar CTBN-modified epoxy
resins, Hycar CTB-modified epoxy resins, urethane-modified epoxy
resins, nitrile rubber-added epoxy resins, cross-linked acrylic
rubber fine particle-added epoxy resins, silicone-modified epoxy
resins and thermoplastic elastomer-added epoxy resins can be
used.
[0073] As the inorganic fine particle fillers, mica, alumina, talc,
silica fine particles, Wollastonite, Sepiolite, basic magnesium
sulfate, calcium carboxylate, polytetrafluoroethylene powder, zinc
powder and aluminum powder can be used.
[0074] As the organic fine particles, thermosetting resin fine
particles, thermoplastic resin fine particles and a mixture of them
can be used.
[0075] Examples of the thermosetting resin fine particles include
epoxy resin fine particles, phenol resin fine particles, melamine
resin fine particles, urea resin fine particles, silicone resin
fine particles, urethane resin fine particles and mixtures of
these.
[0076] Examples of the thermoplastic resin fine particles include
copolyester resin fine particles, polyimide resin fine particles,
polyamide resin fine particles, acrylic fine particles,
butadiene-acrylonitrile resin fine particles, styrene fine
particles, olefin fine particles, nylon fine particles,
butadiene-alkyl methacrylate-styrene copolymer,
acrylate-methacrylate copolymer and mixtures of these. Among them,
acrylic fine particles are preferably used because acrylic fine
particles have good dispersibility in an epoxy resin.
[0077] Examples of methods for producing acrylic fine particles
include (1) polymerization of monomer, (2) chemical treatment of
polymer and (3) mechanical pulverization of polymer. However, the
method (3) is not preferable because this method produces
not-so-fine particles with irregular shapes.
[0078] Examples of the polymerization include emulsion
polymerization, soap-free emulsion polymerization, dispersion
polymerization, seed polymerization, suspension polymerization and
combinations of these. Emulsion polymerization and seed
polymerization are used because these methods provide fine
particles with a partially cross-linked structure, core-shell
structure, hollow structure or polar structure (such as epoxy
group, carboxyl group and hydroxyl group). Partially cross-linked
fine particles and core-shell fine particles obtained by these
methods are preferably used.
[0079] Examples of commercially available products of the
core-shell fine particles include Staphyloid AC3355 (trade name;
manufactured by Ganz Chemical Co., Ltd.) and MX120 (trade name;
manufactured by Kaneka Corporation).
[0080] The toughness enhancing agent (D) is contained preferably 1
to 30 parts by mass, and more preferably 3 to 20 parts by mass per
100 parts by mass of the compound (A) which is a benzoxazine
resin.
[0081] The benzoxazine resin composition may further contain a
nanocarbon(s), a fire retardant(s) and/or a release agent(s) to the
extent that physical properties of the composition are not
affected.
[0082] Examples of the nanocarbons include carbon nanotubes,
fullerenes and their derivatives.
[0083] Examples of the fire retardants include red phosphorous;
phosphates such as triphenyl phosphate, tricresyl phosphate,
trixylenyl phosphate, cresyldiphenyl phosphate, xylenyldiphenyl
phosphate, resorcinol bis(phenyl phosphate) and bisphenol A
bis(diphenyl phosphate); and borate esters.
[0084] Examples of the release agents include silicone oil,
stearate esters and carnauba wax.
[0085] The benzoxazine resin composition may be kneaded by any
method. For example, a kneader, a planetary mixer or a twin screw
extruder may be used. When particles such as a fire retardant and
an inorganic filler, it is preferable to disperse in advance the
particles in a liquid resin component to be contained in the
benzoxazine resin composition using a homomixer, a triple roll
mill, a ball mill, a bead mill or ultrasonic in terms of
dispersibility of the particles. In mixing with a matrix resin,
preliminary dispersing particles and the like, heating, cooling,
pressurization and/or depressurization may be conducted as needed.
In terms of storage stability, it is preferably to put and store a
kneaded product in a refrigerator or a freezer soon after the
kneading.
[0086] The viscosity of the benzoxazine resin composition at
50.degree. C. is preferably 10 to 3000 Pas, more preferably 10 to
2500 Pas and most preferably 100 to 2000 Pas in terms of tackiness
and drapeability. If the viscosity is lower than 10 Pas, the
tackiness may greatly change with time due to sink of the
composition of the present invention; if the viscosity is over 3000
Pas, the tackiness and drapeability may decrease.
[0087] Preferable examples of the reinforcing fiber include glass
fibers, carbon fibers, graphite fibers, aramid fibers, boron
fibers, alumina fibers and silicon-carbide fibers. Two or more of
these fibers can be used in combination, but it is preferable to
used carbon fibers or graphite fibers for obtaining a shaped
product that are lighter and more durable. Various carbon and
graphite fibers are employable according to purposes. To obtain a
composite material that is excellent in shock resistance and has
high stiffness and mechanical strength, the tensile modulus of a
fiber to be used is preferably 150 to 650 GPa, more preferably 200
to 550 GPa, and further more preferably 230 to 500 GPa, which
tensile modulus is obtained from the strand tensile test. The
strand tensile test is conducted according to JISR7601 (1986) that
follows impregnation of a bundle fiber with the resin having a
composition described later and subsequent curing at 130.degree. C.
for 35 minutes.
[0088] The shape of the reinforcing fiber is not particularly
limited. For example, long fibers aligned in a single direction,
tows, fabrics, mats, knits, braids, chopped short fibers with a
length of less than 10 mm are employable. Long fibers are 10 mm or
more continuous single fibers or fiber bundles. Short fibers are
less than 10 mm-long chopped fiber bundles. For uses requiring high
specific strength and specific modulus, it is most suitable to
align fiber bundles in a single direction. For the present
invention, alignments like clothes (fabrics) are also suitable.
[0089] A method for producing the fiber-reinforced resin composite
material 1 will now be described.
[0090] First, the prepreg material 4, which constitutes the outer
panel 2, and the reinforcing portion 3 are prepared.
[0091] The prepreg material 4 is formed by impregnating a
reinforcing fiber with the above-described benzoxazine resin
composition. Examples of methods for the impregnation include wet
methods in which the benzoxazine resin composition is dissolved in
a solvent such as methylethyl ketone and methanol for lowering its
viscosity and then subjected to the impregnation; and hot melt
methods (dry methods) in which the resin composition is heated for
lowering the viscosity.
[0092] In wet methods, a reinforcing fiber is impregnated in a
solution of the benzoxazine resin composition, and then the fiber
is then raised from the solution. Thereafter, the solvent is
vaporized using an oven or the like. On the other hand, in hot melt
methods, a reinforcing fiber is directly impregnated with the
benzoxazine resin composition having viscosity lowered by heating;
otherwise, a film composed of a release paper or the like coated
with the benzoxazine resin composition is prepared, and then the
film is laminated on one or both sides of a reinforcing fiber,
followed by heating and pressurizing the fiber to impregnate the
reinforcing fiber with the resin.
[0093] Hot melt methods are preferable because substantially no
solvent remains in a prepreg.
[0094] The content of the reinforcing fiber in the prepreg material
4 per unit area is preferably 70 to 3000 g/m.sup.2. When the
content of the reinforcing fiber is less than 70 g/m.sup.2,
production processes may be complicated because many sheets need to
be laminated to obtain a certain thickness for obtaining the
fiber-reinforced composite material. On the other hand, the content
of the reinforcing fiber is over 3000 g/m.sup.2, drapeability of a
prepreg may deteriorated. However, in the case where the prepreg
material 4 has a flat or simple curve surface, the content of the
reinforcing fiber can be over 3000 g/m.sup.2.
[0095] As to the weight content of the fiber, the weight content of
the reinforcing fiber is preferably 30 to 90% by mass, more
preferably 35 to 85% by mass, and further more preferably 40 to 80%
by mass. When the weight content of the fiber is less than 30% by
mass, the content of the resin is too large, and thus advantages of
the fiber-reinforced composite material that is excellent in the
specific strength and the specific modulus may not be provided,
and/or calorific value in curing in forming the fiber-reinforced
composite material may be too high. When the weight content of the
fiber is over 90% by mass, insufficient impregnation of resin may
be caused, and thus the obtained composite material may have too
many voids.
[0096] After completing preparation of the prepreg material 4, then
an outer panel-forming (simple-shape portion-forming) is conducted.
In the outer panel-forming, the outer panel 2 is formed by
laminating sheets of the prepreg material 4. In the laminating,
heating and pressurization may be conducted to strengthen the
adhesion of the laminated sheets. The laminated sheets may be
shaped by pressure molding, hot drape mold or vacuum bagging,
before or after the laminated sheets are put in a mold.
[0097] Thereafter, a preform 34 is formed using the reinforcing
fiber 33 so as to be in the shape of the reinforcing portion 3, as
illustrated in FIG. 2. In the forming the preform, a thermoplastic
agent (preferably, it has the composition same as that of the
resin) or the like may be used to conduct thermal fusion for
keeping the shape. Three-dimensional fabrics may also be used.
[0098] After completing the forming the preform, reinforcing
portion-integrating (complex-shape portion-integrating) is then
conducted. In the reinforcing portion-integrating, the preform 34
is formed integrally with the outer panel 2 by matched die molding
using male and female molds. FIG. 3 is an explanatory diagram
illustrating conditions of the reinforcing portion-integrating. As
illustrated in FIG. 3, the outer panel 2 and the preform 34 are
placed and set in a mold 5 that is used for forming the
fiber-reinforced resin composite material 1, and then a resin is
fed by pressure feed. The pressure-fed resin is preferably the
above-described benzoxazine resin composition. This pressure-fed
resin is then flowed out of the mold 5 by a vacuum pump 51. As a
consequence of heating and pressurizing the mold 5, a benzoxazine
resin composition 41 that is pressure-fed to the outer panel 2 and
the preform 34 is cured to form the reinforcing portion 3 and also
integrate the reinforcing portion 3 with the outer panel 2.
[0099] According to the present embodiment, as described above, the
resin that forms the outer panel 2 and the resin that forms the
reinforcing portion 3 are composed of the same components (i.e.,
the benzoxazine resin composition). Thus, their joint face is not a
phase boundary, and the decrease in the strength can be
suppressed.
[0100] If the component(s) of a resin forming the outer panel 2
differ from the component(s) of a resin forming the reinforcing
portion 3 and these resins are compatible with each other, no phase
boundary can consequently be observed, and thus it cannot be clear
how these resins are contained in their compatible blend portion,
resulted in difficulties in designing. In, addition, because these
resins are composed of different components, each of the resins has
coefficient of linear expansion different from the other(s), and
thus the fiber-reinforced resin composite material 1 may curve
after these resins cured are removed from a mold.
[0101] On the contrary, when the resin that forms the outer panel 2
and the resin that forms the reinforcing portion 3 are composed of
the same components, it is able to specify what and how resins are
contained in their blend portion, and there is no difference in
coefficient of linear expansion. The above problems can therefore
be solved. Further, when the resin that forms the outer panel 2 and
the resin that forms the reinforcing portion 3 are composed of the
same components, it is able to obtain the same design allowable
values for the outer panel 2 and the reinforcing portion 3.
[0102] In the present invention, the above embodiments may be
changed appropriately as needed.
[0103] For example, although a matched die molding is described as
an example for the step of reinforcing portion integration in the
above embodiments, other methods that can integrate the outer panel
2 with the reinforcing portion 3 may be used. Examples of such
methods other than a matched die molding include Vacuum-assisted
Resin Transfer Molding (VaRTM). Matched die molding does not
require subsidiary goods that are necessary for Vacuum-assisted
Resin Transfer Molding such as a vacuum pack, and thus can reduce
costs of subsidiary goods and costs of disposing such goods. A
matched die molding is also excellent in dimensional accuracy
compared to Vacuum-assisted Resin Transfer Molding.
[0104] In the above embodiments, the outer panel 2 given as an
example is formed of sheets of the prepreg material 4, but
alternatively, the outer panel 2 may be formed of one sheet of the
prepreg material 4.
[0105] In the above embodiments, the complex-shape portion is
exemplified by the reinforcing portion 3 such as a longeron, but
alternatively, the complex-shape portion may be other portions that
require joint strength to the simple-shape portion such as a
bracket.
Example
[0106] The present invention will now be described in detail with
reference to Example, but the present invention is not limited
thereto.
Example
[0107] The prepreg material 4 is a 0.14 mm-thick, 420 mm-width and
21 mm-depth sheet formed of a benzoxazine resin composition (NF-34
(trade name), manufactured by JX Nippon Oil & Energy
Corporation). The prepreg material 4 contains a reinforcing fiber
that is carbon fiber (T700G (trade name), manufactured by TORAY
INDUSTRIES, INC.) and has a FAW (Fiber Areal Weight) of 150
g/m.sup.2 and an RC of 25 wt %. The outer panel 2 is formed of 16
sheets of the prepreg material 4, the sheets being laminated by
integral molding so that the direction of the carbon fiber in one
sheet differs by 45.degree. compared to that of the carbon fiber in
the next sheet. The thickness of the thus-formed outer panel is
2.24 mm.
[0108] The reinforcing portion 3 used herein is not in the
above-described shape but is a sheet to simplify experiments in
this Example. Abase of the reinforcing portion 3 is a 0.68
mm-thick, 420 mm-wide and 210 mm-deep sheet of a four-layer NCF
(Non Crimp Fabrics). This four-layer NFC contains a reinforcing
fiber that is carbon fiber (T700G (trade name), manufactured by
TORAY INDUSTRIES, INC.) and has a FAW of 692 g/m.sup.2 (173
g/m.sup.2 per sheet). Three sheets of this four-layer NFC are
laminated on the prepreg material 4, and then the resulting product
is put and set in a mold. Subsequently, the benzoxazine resin
composition (NF-34 (trade name), manufactured by JX Nippon Oil
& Energy Corporation) is fed by pressure feed into the mold.
After the outflow, hot-press molding is conducted as monolithic
integration. The fiber-reinforced resin composite material 1 is
thus formed as Example.
Comparative Example 1
[0109] Comparative Example 1 is formed by the same way as Example
is formed except that the prepreg material 4 is formed of an epoxy
resin (Y24S31R150 (product number), manufactured by JX Nippon Oil
& Energy Corporation) and the reinforcing portion 3 is formed
of an epoxy resin (EPOLAM5015 (trade name), manufactured by
AXSON).
Comparative Example 2
[0110] Comparative Example 2 is formed by the same way as
Comparative Example 1 is formed except that the reinforcing portion
3 is formed of an epoxy resin (PR520 (trade name), manufactured by
Cvtec).
[0111] [Comparison]
[0112] Example, Comparative Examples 1 and 2 were subjected to an
interlaminar shear strength test by a method according to ASTM
D2344, and further, subjected to a four-point flexural strength
test by a method according to ASTM D6272.
[0113] In addition, outer panels 2 were each formed by integral
molding through laminating 32 sheets of the prepreg material 4 of
Example, Comparative Examples 1 or 2 so that the direction of the
carbon fiber in one sheet differs by 45.degree. compared to that of
the carbon fiber in the next sheet. These outer panels were also
subjected to an interlaminar shear strength test and a four-point
flexural strength by the above methods.
[0114] [Result of Comparison]
TABLE-US-00001 TABLE 1 COMPARATIVE COMPARATIVE EXAMPLE EXAMPLE 1
EXAMPLE 2 INTERLAMINAR SHEAR OUTER 47.5 45.1 45.1 STRENGTH (Mpa)
PANEL ONLY WHOLE 72.0 54.9 41.7 FOUR-POINT FLEXURAL OUTER 514 602
602 STRENGTH (Mpa) PANEL ONLY WHOLE 674 574 303
[0115] Results of the comparison are shown in Table 1 and FIGS. 4
and 5.
[0116] In the comparison of the outer panels 2 only, interlaminar
shear strength and four-point flexural strength of Example are not
so different from Comparative Examples 1 and 2. However, in the
comparison of the fiber-reinforced resin composite materials 1 as a
whole, interlaminar shear strength and four-point flexural strength
of Example are remarkably improved compared to Comparative Examples
1 and 2.
DESCRIPTION OF REFERENCE NUMERALS
[0117] 1 Fiber-reinforced resin composite material [0118] 2 Outer
panel (Simple-shape portion) [0119] 3 Reinforcing portion
(Complex-shape portion) [0120] 4 Prepreg material [0121] 5 Mold
[0122] 6 Mold [0123] 31 Base portion [0124] 32 Rib [0125] 33
Reinforcing fiber [0126] 34 Preform [0127] 51 Vacuum pump [0128] 61
Benzoxazine resin composition
* * * * *