U.S. patent application number 16/970904 was filed with the patent office on 2020-12-10 for continuous-fiber-reinforced resin molding and method for manufacturing same.
This patent application is currently assigned to Asahi Kasei Kabushiki Kaisha. The applicant listed for this patent is Asahi Kasei Kabushiki Kaisha. Invention is credited to Tsutomu Akiyama, Yusuke Aratani, Toru Koizumi.
Application Number | 20200384704 16/970904 |
Document ID | / |
Family ID | 1000005074774 |
Filed Date | 2020-12-10 |
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United States Patent
Application |
20200384704 |
Kind Code |
A1 |
Aratani; Yusuke ; et
al. |
December 10, 2020 |
Continuous-Fiber-Reinforced Resin Molding and Method for
Manufacturing Same
Abstract
Provided are a continuous fiber-reinforced resin molding having
high adhesion and compatibility in an interface between continuous
reinforcing fibers and a synthetic resin, and in which a low
occurrence of voids in the interface and adequate strength can be
realized, and a method for manufacturing the same. A continuous
fiber-reinforced resin molding comprising a synthetic resin and
continuous reinforcing fibers having a substantially circular cross
section, the continuous fiber-reinforced molding being
characterized in that the number of continuous reinforcing fibers
where the porosity in a peripheral-edge region separated by one
tenth the radius of a single continuous reinforcing fiber from the
peripheral edge part of the continuous reinforcing fibers in the
interface between the synthetic resin and the single continuous
reinforcing fiber in a cross section orthogonal to the length
direction of the continuous reinforcing fibers is at least 10% of
the total number of continuous reinforcing fibers.
Inventors: |
Aratani; Yusuke; (Tokyo,
JP) ; Akiyama; Tsutomu; (Tokyo, JP) ; Koizumi;
Toru; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Asahi Kasei Kabushiki Kaisha |
Tokyo |
|
JP |
|
|
Assignee: |
Asahi Kasei Kabushiki
Kaisha
Tokyo
JP
|
Family ID: |
1000005074774 |
Appl. No.: |
16/970904 |
Filed: |
April 23, 2019 |
PCT Filed: |
April 23, 2019 |
PCT NO: |
PCT/JP2019/017285 |
371 Date: |
August 18, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 70/16 20130101;
B29L 2031/3481 20130101; B29C 70/42 20130101; C08J 2377/00
20130101; B29C 43/52 20130101; C08J 5/24 20130101; B29K 2309/08
20130101; B29K 2105/0005 20130101; B29K 2101/12 20130101; B29K
2105/0872 20130101; B29K 2077/00 20130101 |
International
Class: |
B29C 70/16 20060101
B29C070/16; B29C 43/52 20060101 B29C043/52; B29C 70/42 20060101
B29C070/42; C08J 5/24 20060101 C08J005/24 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 25, 2018 |
JP |
2018-083938 |
Apr 25, 2018 |
JP |
2018-083949 |
Jul 25, 2018 |
JP |
2018-139322 |
Jul 25, 2018 |
JP |
2018-139342 |
Jul 25, 2018 |
JP |
2018-139396 |
Nov 30, 2018 |
JP |
2018-225610 |
Claims
1. A continuous fiber-reinforced molded resin comprising continuous
reinforcing fibers with approximately circular cross-sections and a
synthetic resin, wherein at the interface between each single
continuous reinforcing fiber and the synthetic resin in a
cross-section perpendicular to the lengthwise direction of the
continuous reinforcing fiber, the number of continuous reinforcing
fibers in which the void percentage within the region of the outer
peripheral edge separated from the perimeter of the continuous
reinforcing fiber by 1/10 of the radius of a single continuous
reinforcing fiber is 10% or lower, is at least 10% of the total
number of continuous reinforcing fibers.
2. The continuous fiber-reinforced molded resin according to claim
1, wherein the number of continuous reinforcing fibers in which the
void percentage is 10% or lower is at least 90% of the total number
of continuous reinforcing fibers.
3. The continuous fiber-reinforced molded resin according to claim
2, wherein the number of continuous reinforcing fibers in which the
void percentage is 1% or lower is at least 90% of the total number
of continuous reinforcing fibers.
4-6. (canceled)
7. A continuous fiber-reinforced molded resin according to claim 1,
comprising a thermoplastic resin and continuous reinforcing fibers,
and having a loss tangent of 0.11 or lower in twisting mode.
8. The continuous fiber-reinforced molded resin according to claim
7, wherein the peak temperature of the loss tangent is 78.degree.
C. or higher.
9. A continuous fiber-reinforced molded resin according to claim 1,
comprising continuous reinforcing fibers and a thermoplastic resin,
and having a storage modulus of 3.4 GPa or greater in twisting
mode.
10. The continuous fiber-reinforced molded resin according to claim
9, which when cut in a diagonal direction has a storage modulus of
at least 1.5 times the storage modulus when cut in a straight
direction.
11. The continuous fiber-reinforced molded resin according to claim
9, wherein the storage modulus at 150.degree. C. is at least 25% of
the maximum storage modulus.
12. The continuous fiber-reinforced molded resin according to claim
9, wherein the shear viscosity is 330 MPas.sup.-1 or greater.
13. A continuous fiber-reinforced molded resin according to claim
1, comprising continuous reinforcing fibers and a thermoplastic
resin, and having a bending storage modulus of 22 GPa or
greater.
14. The continuous fiber-reinforced molded resin according to claim
13, wherein the bending storage modulus at 150.degree. C. is at
least 76% of the storage modulus at 30.degree. C.
15. The continuous fiber-reinforced molded resin according to claim
13, wherein the bending storage modulus retention when cut
diagonally is 58% or higher.
16. The continuous fiber-reinforced molded resin according to claim
13, wherein the tensile storage modulus at 50.degree. C. is 22 GPa
or greater.
17. The continuous fiber-reinforced molded resin according to claim
13, wherein the maximum tensile loss tangent is 0.037 or lower.
18. The continuous fiber-reinforced molded resin according to claim
13, wherein the temperature at which the tensile storage modulus
and bending storage modulus are reversed is 95.degree. C. or
higher.
19. The continuous fiber-reinforced molded resin according to claim
13, wherein {(tensile storage modulus-bending storage modulus) at
30.degree. C.}/{(bending storage modulus-tensile storage modulus)
at 200.degree. C.}.gtoreq.1.
20. A continuous fiber-reinforced molded resin according to claim
1, comprising continuous reinforcing fibers with approximately
circular cross-sections and two or more thermoplastic resins,
wherein at the interface between a single continuous reinforcing
fiber and the thermoplastic resin in a cross-section perpendicular
to the lengthwise direction of the continuous reinforcing fiber, in
a region of the outer peripheral edge separated from the perimeter
of the continuous reinforcing fiber by 1/10 of the radius of a
single continuous reinforcing fiber, the proportion of the two or
more thermoplastic resins that is occupied by resin other than the
resin with the highest occupying proportion of the entire resin
region, is higher than the proportion occupied by the resin with
the highest occupying proportion of the entire resin region, while
in the resin region other than that region of the outer peripheral
edge, the resin other than the resin with the highest occupying
proportion of the entire resin region, of the two or more
thermoplastic resins, is either evenly dispersed or mixed.
21. The continuous fiber-reinforced molded resin according to claim
20, wherein the two or more thermoplastic resins have a sea-island
structure.
22. The continuous fiber-reinforced molded resin according to claim
20, wherein the difference between the melting point of the resin
with the highest melting point and the melting point of the resin
with the lowest melting point of the two or more thermoplastic
resins is 100.degree. C. or greater.
23. (canceled)
24. The continuous fiber-reinforced molded resin according to claim
20, wherein the difference between the melting peak temperature
during temperature increase and the crystallization peak
temperature during temperature decrease for the mixture of the two
or more thermoplastic resins is smaller than the difference between
the melting peak temperature during temperature increase and the
crystallization peak temperature during temperature decrease for
the resin with the highest occupying proportion of the entire resin
region, of the two or more thermoplastic resins.
25. The continuous fiber-reinforced molded resin according to claim
20, wherein of the two or more thermoplastic resins, the bonding
strength between at least one resin other than the resin with the
highest occupying proportion of the entire resin region and the
continuous reinforcing fibers is larger than the bonding strength
between the resin with the highest occupying proportion of the
entire resin region and the continuous reinforcing fibers.
26. The continuous fiber-reinforced molded resin according to claim
20, wherein of the two or more thermoplastic resins, the difference
in surface tension between at least one resin other than the resin
with the highest occupying proportion of the entire resin region
and the continuous reinforcing fibers is smaller than the
difference in surface tension between the resin with the highest
occupying proportion of the entire resin region and the continuous
reinforcing fibers.
27. The continuous fiber-reinforced molded resin according to claim
20, wherein of the two or more thermoplastic resins, the
wettability of at least one resin other than the resin with the
highest occupying proportion of the entire resin region for the
continuous reinforcing fibers is higher than the wettability of the
resin with the highest occupying proportion of the entire resin
region for the continuous reinforcing fibers.
28. A method for producing a continuous fiber-reinforced resin
composite material, the method comprising the following steps: a
step of hot pressing continuous reinforcing fibers that have
addition of a sizing agent comprising a coupling agent, binding
agent and lubricating agent, with a thermoplastic resin having
terminal functional groups that are reactive with the coupling
agent, at above the melting point of the thermoplastic resin, and a
step of cooling to below the melting point of the thermoplastic
resin to obtain a continuous fiber-reinforced resin composite
material as a molded article.
29. The method according to claim 28, wherein the absorption
percentage of the thermoplastic resin is 0.1 wt % or greater.
30. The method according to claim 28, wherein at least 50 wt % of
the sizing agent diffuses in the thermoplastic resin during hot
pressing.
31. (canceled)
32. The method according to claim 28, wherein the amount of
terminal functional groups in the continuous fiber-reinforced resin
composite material is less than the amount of terminal functional
groups in the thermoplastic resin.
33. The method according to claim 28, wherein the amount of
terminal functional groups is 90% or less of the amount of terminal
functional groups in the thermoplastic resin.
34. The method according to claim 28, wherein the content of
particulate additives in the thermoplastic resin is 30 ppm or
lower.
35. The method according to claim 28, wherein the thermoplastic
resin is a polyamide resin, and the amount of carboxyl ends in the
polyamide resin, as terminal functional groups that are reactive
with the coupling agent, is at least 65 .mu.mol/g.
36. The method according to claim 28, wherein the thermoplastic
resin is a polyamide resin, and the amount of amino ends in the
polyamide resin, as terminal functional groups that are reactive
with the coupling agent, is 40 .mu.mol/g or lower.
37. (canceled)
38. (canceled)
39. A method for producing a continuous fiber-reinforced molded
resin according to claim 1, comprising a step of hot pressing
reinforcing fibers and a thermoplastic resin that has a .mu.-drop
formation coefficient with the reinforcing fibers of 10 or greater,
to above the melting point of the thermoplastic resin, and a step
of cooling to below the crystallization temperature of the
thermoplastic resin.
40. A fiber-reinforced molded resin comprising continuous
reinforcing fibers according to claim 1 made of glass and a
polyamide resin, wherein when the fiber-reinforced molded resin is
cut and the polished surface that has been polished with a force of
400 g/cm.sup.2 is observed by SEM, at the interface between a
single continuous reinforcing fiber made of glass and the polyamide
resin in a cross-section perpendicular to the lengthwise direction
of the continuous reinforcing fiber made of glass, the number of
continuous reinforcing fibers made of glass in which the void
percentage within the region of the outer peripheral edge separated
from the perimeter of the continuous reinforcing fiber made of
glass by 1/10 of the radius of a single continuous reinforcing
fiber made of glass is 10% or lower, is at least 90% of the total
number of continuous reinforcing fibers made of glass.
41. (canceled)
42. A communication device housing constituted by a composite
material molded article comprising a thermoplastic resin and
continuous reinforcing fibers according to claim 1, wherein the
tensile strength satisfies the relationship specified by the
following formula (3): Tensile strength (MPa) in lengthwise
direction.times.0.5+tensile strength (MPa) in widthwise
direction.times.0.5>500 MPa Formula (3), the flexural modulus
satisfies the relationship specified by the following formula (4):
Flexural modulus (MPa) in lengthwise direction.times.0.5+flexural
modulus (MPa) in widthwise direction.times.0.5>30 MPa Formula
(4), and the electric field shielding property measured by the KEC
method is 10 dB or lower in the frequency band of 1 GHz.
43. A continuous fiber-reinforced molded resin constituted by
continuous reinforcing fibers and a thermoplastic resin, wherein
the breaking strength due to interlayer separation is 40 MPa or
higher in acoustic emission measurement.
Description
FIELD
[0001] The present invention relates to a continuous
fiber-reinforced molded resin and to a method for its production.
More specifically, the invention relates to a continuous
fiber-reinforced molded resin having high adhesive force and
affinity at the interface between the continuous reinforcing fibers
and the synthetic resin, having small voids in the interface and
exhibiting adequate strength, to a continuous fiber-reinforced
molded resin with a sufficiently small loss tangent of the
continuous fiber-reinforced molded resin and capable of exhibiting
sufficient shock absorption, to a continuous fiber-reinforced
molded resin with a sufficiently large storage modulus of the
continuous fiber-reinforced molded resin and capable of exhibiting
sufficient impact strength, and to a continuous fiber-reinforced
molded resin having a high resin impregnating property and high
strength and rigidity, as well as to a method for producing the
same.
BACKGROUND
[0002] Molded composite materials having a reinforcing material
such as glass fibers added to a matrix resin material, have been
used in structural parts of various machines and vehicles, or in
pressure vessels or tubular structures. In a continuous
fiber-reinforced molded resin it is preferred for the reinforcing
fibers to be continuous fibers from the viewpoint of strength, and
for the resin to be a thermoplastic resin from the viewpoint of the
molding cycle and recycling properties. The continuous
fiber-reinforced molded resins that have previously been proposed
include those with a modified sizing agent added to reinforcing
fibers (see PTL 1, for example), those with a modified difference
between the melting temperature (melting point) and crystallization
temperature of the thermoplastic resin (see PTL 2, for example),
those with an organic salt added to a resin material (see PTL 3,
for example), those with a molding precursor fabric layered with a
thermoplastic resin (see PTL 4, for example), those with
reinforcing fibers pre-impregnated with a low-melting-point
thermoplastic resin to increase the impregnating property (see PTL
5, for example), and those using two or more resins with different
melting points as the surface resins to impart satisfactory
resistance against interlayer separation (see PTL 6, for
example).
CITATION LIST
Patent Literature
[0003] [PTL 1] Japanese Unexamined Patent Publication No.
2003-238213 [0004] [PTL 2] Japanese Patent Publication No. 5987335
[0005] [PTL 3] Japanese Unexamined Patent Publication No.
2017-222859 [0006] [PTL 4] Japanese Unexamined Patent Publication
No. 2009-19202 [0007] [PTL 5] Japanese Unexamined Patent
Publication HEI No. 10-138379 [0008] [PTL 6] Japanese Patent
Publication No. 5878544
SUMMARY
Technical Problem
[0009] As a result of ardent research, the present inventors have
found that continuous fiber-reinforced molded resins of the prior
art all have low adhesive force and affinity at the boundaries
between the continuous reinforcing fibers, such as glass fibers,
and the matrix resin, and consequently have many voids and fail to
exhibit sufficient strength in the interface regions between the
fibers and resin, so that they do not exhibit the performance
required for use in locations where high strength is necessary.
Moreover, it has been found that continuous fiber-reinforced molded
resins of the prior art all have high loss tangents and therefore
fail to exhibit sufficient shock absorption and lack performance
required for use in locations where high shock absorption is
necessary, that they have low storage moduli and thus fail to
exhibit sufficient impact strength and lack performance required
for use in locations where high impact strength is necessary, and
also that the property of resin impregnation into the continuous
reinforcing fibers is low, the adhesion between the resin and
continuous reinforcing fibers is inadequate, and the physical
properties such as strength and rigidity, as well as productivity,
are poor.
[0010] Considering the technical level of the prior art, it is an
object of the present invention to provide a continuous
fiber-reinforced molded resin having high adhesive force and
affinity at the interface between the continuous reinforcing fibers
and the synthetic resin, having small voids in the interface and
exhibiting adequate strength, a continuous fiber-reinforced molded
resin with a small loss tangent and capable of exhibiting
sufficient impact strength, a continuous fiber-reinforced molded
resin having a high storage modulus and capable of exhibiting
sufficient impact strength, and a continuous fiber-reinforced
molded resin having a high resin impregnating property and high
strength and rigidity, as well as a method for producing the
same.
Solution to Problem
[0011] As a result of accumulated research on the object stated
above, the present inventors have completed this invention upon the
unexpected finding that modifying the compatibility between the
resin and the sizing agent that is coated during production of
continuous reinforcing fibers, and the sealability during molding
and of flow of the resin, can drastically reduce voids at the
interface between the continuous reinforcing fibers and synthetic
resin, so that press molding thereof allows production of a
continuous fiber-reinforced molded resin having high strength and
rigidity, while also lowering the loss tangent of the continuous
fiber-reinforced molded resin so that press molding thereof allows
production of a continuous fiber-reinforced molded resin having
high shock absorption, and increasing the storage modulus of the
continuous fiber-reinforced molded resin so that press molding
thereof allows production of a continuous fiber-reinforced molded
resin having high impact strength, and further that in a continuous
fiber-reinforced molded resin having two or more thermoplastic
resins, if the proportion of each resin at the interface regions
between the continuous reinforcing fibers and resin is different
than the proportion of each resin in the other resin regions, then
the continuous fiber-reinforced molded resin exhibits high strength
and rigidity.
[0012] Specifically, the present invention provides the
following.
[0013] [1] A continuous fiber-reinforced molded resin comprising
continuous reinforcing fibers with approximately circular
cross-sections and a synthetic resin, wherein at the interface
between each single continuous reinforcing fiber and the synthetic
resin in a cross-section perpendicular to the lengthwise direction
of the continuous reinforcing fiber, the number of continuous
reinforcing fibers in which the void percentage within the region
of the outer peripheral edge separated from the perimeter of the
continuous reinforcing fiber by 1/10 of the radius of a single
continuous reinforcing fiber is 10% or lower, is at least 10% of
the total number of continuous reinforcing fibers.
[0014] [2] The continuous fiber-reinforced molded resin according
to [1] above, wherein the number of continuous reinforcing fibers
in which the void percentage is 10% or lower is at least 90% of the
total number of continuous reinforcing fibers.
[0015] [3] The continuous fiber-reinforced molded resin according
to [2] above, wherein the number of continuous reinforcing fibers
in which the void percentage is 1% or lower is at least 90% of the
total number of continuous reinforcing fibers.
[0016] [4] The continuous fiber-reinforced molded resin according
to any one of [1] to [3] above, wherein the synthetic resin
impregnation rate in the continuous fiber-reinforced molded resin
is 99% or higher.
[0017] [5] The continuous fiber-reinforced molded resin according
to any one of [1] to [4] above, wherein the continuous reinforcing
fibers are glass fibers, and the tensile stress of the continuous
fiber-reinforced molded resin is 480 MPa or higher.
[0018] [6] The continuous fiber-reinforced molded resin according
to any one of [1] to [5] above, wherein the continuous reinforcing
fibers are glass fibers, and the flexural modulus of the continuous
fiber-reinforced molded resin is 22 GPa or greater.
[0019] [7] A continuous fiber-reinforced molded resin comprising a
thermoplastic resin and continuous reinforcing fibers, and having a
loss tangent of 0.11 or lower in twisting mode.
[0020] [8] The continuous fiber-reinforced molded resin according
to [7] above, wherein the peak of the loss tangent is 78.degree. C.
or higher.
[0021] [9] A continuous fiber-reinforced molded resin comprising
continuous reinforcing fibers and a thermoplastic resin, and having
a storage modulus of 3.4 GPa or greater in twisting mode.
[0022] [10] The continuous fiber-reinforced molded resin according
to [9] above, which when cut in a diagonal direction has a storage
modulus of at least 1.5 times the storage modulus when cut in a
straight direction.
[0023] [11] The continuous fiber-reinforced molded resin according
to [9] or [10] above, wherein the storage modulus at 150.degree. C.
is at least 25% of the maximum storage modulus.
[0024] [12] The continuous fiber-reinforced molded resin according
to any one of [9] to [11], wherein the shear viscosity is 330
MPas.sup.-1 or greater.
[0025] [13] A continuous fiber-reinforced molded resin comprising
continuous reinforcing fibers and a thermoplastic resin, and having
a bending storage modulus of 22 GPa or greater.
[0026] [14] The continuous fiber-reinforced molded resin according
to [13] above, wherein the bending storage modulus at 150.degree.
C. is at least 76% of the storage modulus at 30.degree. C.
[0027] [15] The continuous fiber-reinforced molded resin according
to [13] or [14] above, wherein the bending storage modulus
retention when cut diagonally is 58% or higher.
[0028] [16] The continuous fiber-reinforced molded resin according
to any one of [13] to [15] above, wherein the tensile storage
modulus at 50.degree. C. is 22 GPa or greater.
[0029] [17] The continuous fiber-reinforced molded resin according
to any one of [13] to [16] above, wherein the maximum tensile loss
tangent is 0.037 or lower.
[0030] [18] The continuous fiber-reinforced molded resin according
to any one of [13] to [17] above, wherein the temperature at which
the tensile storage modulus and bending storage modulus are
reversed is 95.degree. C. or higher.
[0031] [19] The continuous fiber-reinforced molded resin according
to any one of [13] to [18] above, wherein {(tensile storage
modulus-bending storage modulus) at 30.degree. C.}/{(bending
storage modulus-tensile storage modulus) at 200.degree.
C.}.gtoreq.1.
[0032] [20] A continuous fiber-reinforced molded resin comprising
continuous reinforcing fibers with approximately circular
cross-sections and two or more thermoplastic resins, wherein at the
interface between a single continuous reinforcing fiber and the
thermoplastic resin in a cross-section perpendicular to the
lengthwise direction of the continuous reinforcing fiber, in a
region of the outer peripheral edge separated from the perimeter of
the continuous reinforcing fiber by 1/10 of the radius of a single
continuous reinforcing fiber of the two or more different types,
the proportion of the two or more thermoplastic resins that is
occupied by resin other than the resin with the highest occupying
proportion of the entire resin region, is higher than the
proportion occupied by the resin with the highest occupying
proportion of the entire resin region, while in the resin region
other than that region of the outer peripheral edge, each of the
resins other than the resin with the highest occupying proportion
of the entire resin region, of the two or more thermoplastic
resins, is either evenly dispersed or mixed.
[0033] [21] The continuous fiber-reinforced molded resin according
to [20] above, wherein the two or more thermoplastic resins have a
sea-island structure.
[0034] [22] The continuous fiber-reinforced molded resin according
to [20] or [21] above, wherein the difference between the melting
point of the resin with the highest melting point and the melting
point of the resin with the lowest melting point of the two or more
thermoplastic resins is 100.degree. C. or greater.
[0035] [23] The continuous fiber-reinforced molded resin according
to any one of [20] to [22] above, wherein the melting point of the
mixture of the two or more thermoplastic resins is essentially the
same as the melting point of the resin with the highest occupying
proportion of the entire resin region, of the two or more
thermoplastic resins.
[0036] [24] The continuous fiber-reinforced molded resin according
to any one of [20] to [23] above, wherein the difference between
the melting peak temperature during temperature increase and the
crystallization peak temperature during temperature decrease for
the mixture of the two or more thermoplastic resins is smaller than
the difference between the melting peak temperature during
temperature increase and the crystallization peak temperature
during temperature decrease for the resin with the highest
occupying proportion of the entire resin region, of the two or more
thermoplastic resins.
[0037] [25] The continuous fiber-reinforced molded resin according
to any one of [20] to [24] above, wherein of the two or more
thermoplastic resins, the bonding strength between at least one
resin other than the resin with the highest occupying proportion of
the entire resin region and the continuous reinforcing fibers is
larger than the bonding strength between the resin with the highest
occupying proportion of the entire resin region and the continuous
reinforcing fibers.
[0038] [26] The continuous fiber-reinforced molded resin according
to any one of [20] to [25] above, wherein of the two or more
thermoplastic resins, the difference in surface tension between at
least one resin other than the resin with the highest occupying
proportion of the entire resin region and the continuous
reinforcing fibers is smaller than the difference in surface
tension between the resin with the highest occupying proportion of
the entire resin region and the continuous reinforcing fibers.
[0039] [27] The continuous fiber-reinforced molded resin according
to any one of [20] to [26] above, wherein of the two or more
thermoplastic resins, the wettability of at least one resin other
than the resin with the highest occupying proportion of the entire
resin region for the continuous reinforcing fibers is higher than
the wettability of the resin with the highest occupying proportion
of the entire resin region for the continuous reinforcing
fibers.
[0040] [28] A method for producing a continuous fiber-reinforced
resin composite material, the method comprising the following
steps:
[0041] a step of hot pressing continuous reinforcing fibers that
have addition of a sizing agent comprising a coupling agent,
binding agent and lubricating agent, with a thermoplastic resin
having terminal functional groups that are reactive with the
coupling agent, at above the melting point of the thermoplastic
resin, and
[0042] a step of cooling to below the melting point of the
thermoplastic resin to obtain a continuous fiber-reinforced resin
composite material as a molded article.
[0043] [29] The method according to [28] above, wherein the
absorption percentage of the thermoplastic resin is 0.1 wt % or
greater.
[0044] [30] The method according to [28] or [29] above, wherein at
least 50 wt % of the sizing agent diffuses in the thermoplastic
resin during hot pressing.
[0045] [31] The method according to any one of [28] to [30] above,
wherein the coupling agent and the terminal functional groups of
the thermoplastic resin are bonded.
[0046] [32] The method according to any one of [28] to [31] above,
wherein the amount of terminal functional groups in the continuous
fiber-reinforced resin composite material is less than the amount
of terminal functional groups in the thermoplastic resin.
[0047] [33] The method according to any one of [28] to [32] above,
wherein the amount of terminal functional groups is 90% or less of
the amount of terminal functional groups in the thermoplastic
resin.
[0048] [34] The method according to any one of [28] to [33] above,
wherein the content of particulate additives in the thermoplastic
resin is 30 ppm or lower.
[0049] [35] The method according to any one of [28] to [34] above,
wherein the thermoplastic resin is a polyamide resin, and the
amount of carboxyl ends in the polyamide resin, as terminal
functional groups that are reactive with the coupling agent, is at
least 65 .mu.mol/g.
[0050] [36] The method according to any one of [28] to [35] above,
wherein the thermoplastic resin is a polyamide resin, and the
amount of amino ends in the polyamide resin, as terminal functional
groups that are reactive with the coupling agent, is 40 .mu.mol/g
or lower.
[0051] [37] A method for producing a shaped molded article of a
continuous fiber-reinforced resin composite material, comprising a
step of heating a continuous fiber-reinforced resin composite
material produced by the method according to any one of [28] to
[36] at above the melting point of the thermoplastic resin,
pressing it using a die, and then cooling to a temperature below
the melting point of the thermoplastic resin and shaping it.
[0052] [38] The method according to [37] above, wherein compression
is carried out during the cooling.
[0053] [39] A method for producing a fiber-reinforced molded resin,
comprising a step of hot pressing reinforcing fibers and a
thermoplastic resin that has a .mu.-drop formation coefficient with
the reinforcing fibers of 10 or greater, to above the melting point
of the thermoplastic resin, and a step of cooling to below the
crystallization temperature of the thermoplastic resin.
[0054] [40] A fiber-reinforced molded resin comprising glass fibers
and a polyamide resin, wherein when the fiber-reinforced molded
resin is cut and the polished surface that has been polished with a
force of 400 g/cm.sup.2 is observed by SEM, at the interface
between a single glass fiber and the polyamide resin in a
cross-section perpendicular to the lengthwise direction of the
glass fiber, the number of glass fibers in which the void
percentage within the region of the outer peripheral edge separated
from the perimeter of the glass fiber by 1/10 of the radius of a
single glass fiber is 10% or lower, is at least 90% of the total
number of glass fibers.
[0055] [41] The continuous fiber-reinforced molded resin according
to [40] above, wherein the glass fibers are continuous fibers.
[0056] [42] A communication device housing constituted by a
composite material molded article comprising a thermoplastic resin
and continuous glass reinforcing fibers, wherein the tensile
strength satisfies the relationship specified by the following
formula (3):
Tensile strength (MPa) in lengthwise direction.times.0.5+tensile
strength (MPa) in widthwise direction.times.0.5>500 MPa Formula
(3),
the flexural modulus satisfies the relationship specified by the
following formula (4):
Flexural modulus (MPa) in lengthwise direction.times.0.5+flexural
modulus (MPa) in widthwise direction.times.0.5>30 MPa Formula
(4),
and the electric field shielding property measured by the KEC
method is 10 dB or lower in the frequency band of 1 GHz.
[0057] [43] A continuous fiber-reinforced molded resin constituted
by continuous reinforcing fibers and a thermoplastic resin, wherein
the breaking strength due to interlayer separation is 40 MPa or
higher in acoustic emission measurement.
Advantageous Effects of Invention
[0058] The continuous fiber-reinforced molded resin of the
invention has high adhesive force and affinity at the interface
between the continuous reinforcing fibers and the synthetic resin,
has small voids in the interface and exhibits adequate strength,
rigidity and impact strength and high long-term properties, while
also having a sufficiently small loss tangent and exhibiting
sufficient shock absorption, having a sufficiently large storage
modulus and exhibiting sufficient impact strength, and having a
high resin impregnating property and high strength and
rigidity.
BRIEF DESCRIPTION OF DRAWINGS
[0059] FIG. 1 is a diagram illustrating the "voids" and "void
percentage" in the region of the outer peripheral edge separated
from the perimeter of the continuous reinforcing fiber by 1/10 of
the radius of the single continuous reinforcing fiber, at the
interface between a single continuous reinforcing fiber and the
synthetic resin (interface region), in a cross-section
perpendicular to the lengthwise direction of the continuous
reinforcing fiber.
[0060] FIG. 2 is a photograph of the interface regions for Example
1-1, Example 2-1, Example 3-1 and Example 4-1.
[0061] FIG. 3 is a photograph of the interface regions for Example
1-3.
[0062] FIG. 4 is a photograph of the interface regions for
Comparative Example 1-2.
[0063] FIG. 5 is a photograph of the interface regions for
Comparative Example 1-3.
[0064] FIG. 6 is a photograph in lieu of a drawing, for
illustration of the "impregnation rate" of a synthetic resin in a
continuous fiber-reinforced molded resin.
[0065] FIG. 7 is a photograph in lieu of a drawing, showing a state
where, at the interface between a single continuous reinforcing
fiber and a synthetic resin in a cross-section along the lengthwise
direction of a continuous reinforcing fiber with an approximately
circular cross-section, in a region of the outer peripheral edge
separated from the perimeter of the continuous reinforcing fiber by
1/10 of the radius of the single continuous reinforcing fiber, the
proportion of the two or more thermoplastic resins that is occupied
by resin other than the resin with the highest occupying proportion
of the entire resin region, is higher than the proportion occupied
by the resin with the highest occupying proportion of the entire
resin region, but in the resin region other than that region of the
outer peripheral edge, the resin other than the resin with the
highest occupying proportion of the entire resin region, of the two
or more thermoplastic resins, is evenly dispersed.
[0066] FIG. 8 is a photograph of the interface regions for Example
6-1.
[0067] FIG. 9 is a photograph of the interface regions for
Comparative Example 6-2.
[0068] FIG. 10 is a photograph of the interface regions for Example
10.
[0069] FIG. 11 is a photograph of the interface regions for
Comparative Example 10.
[0070] FIG. 12 is a diagram showing the shape of a smartphone
housing for Example 9.
DESCRIPTION OF EMBODIMENTS
[0071] Embodiments of the invention will now be explained in
detail.
[Continuous Fiber-Reinforced Molded Resin]
[0072] The continuous fiber-reinforced molded resin of the
embodiment is a continuous fiber-reinforced molded resin
constituted by continuous reinforcing fibers with an approximately
circular cross-section and a synthetic resin, wherein preferably,
the number of continuous reinforcing fibers in which the void
percentage in the region of the outer peripheral edge separated
from the perimeter of the continuous reinforcing fiber by 1/10 of
the radius of a single continuous reinforcing fiber, at the
interface between each single continuous reinforcing fiber and the
synthetic resin in a cross-section perpendicular to the lengthwise
direction of the continuous reinforcing fiber, is 10% or lower, is
at least 10% of the total number of continuous reinforcing fibers,
the loss tangent (tan .delta.) is 0.11 or lower with dynamic
viscoelasticity measurement in twisting mode, the storage modulus
is 3.4 GPa or greater with dynamic viscoelasticity measurement in
twisting mode, and the storage modulus is 22 GPa or greater in
bending mode. When two or more different thermoplastic resins are
used, preferably at the interface between a single continuous
reinforcing fiber and the thermoplastic resin in a cross-section
perpendicular to the lengthwise direction of the continuous
reinforcing fiber, in a region of the outer peripheral edge
separated from the perimeter of the continuous reinforcing fiber by
1/10 of the radius of a single continuous reinforcing fiber (also
referred to as the "interface region"), the proportion of the two
or more thermoplastic resins that is occupied by a resin (also
referred to as "secondary resin") other than the resin with the
highest occupying proportion of the entire resin region (also
referred to as "primary resin"), is higher than the proportion
occupied by the resin with the highest occupying proportion of the
entire resin region, while in the resin region other than that
region of the outer peripheral edge (also referred to as "other
resin region"), the resin (secondary resin) other than the resin
with the highest occupying proportion of the entire resin region,
of the two or more thermoplastic resins, is either evenly dispersed
or mixed.
[0073] The method for producing a continuous fiber-reinforced resin
composite material of this embodiment preferably comprises the
following steps:
[0074] a step of hot pressing continuous reinforcing fibers that
have addition of a sizing agent comprising a coupling agent,
binding agent and lubricating agent, with a thermoplastic resin
having terminal functional groups that are reactive with the
coupling agent, at above the melting point of the thermoplastic
resin, and
[0075] a step of cooling to below the melting point of the
thermoplastic resin to obtain a continuous fiber-reinforced resin
composite material as a molded article.
[0076] In other words, as shown in FIG. 1, the continuous
fiber-reinforced molded resin of the embodiment is a continuous
fiber-reinforced molded resin comprising continuous reinforcing
fibers with approximately circular cross-sections and a synthetic
resin, wherein continuous reinforcing fibers are present which have
a void percentage of 10% or lower in the region of the outer
peripheral edge that is separated from the perimeter of each
continuous reinforcing fiber by 1/10 of the radius r of a single
continuous reinforcing fiber (i.e., r/10) in the radial direction
(also referred to as "interface region"), when observed at the
interface between a single continuous reinforcing fiber and the
synthetic resin in a cross-section perpendicular to the lengthwise
direction of the continuous reinforcing fiber, and their number is
at least 10% of the total number of continuous reinforcing fibers.
While the cross-sections of the continuous reinforcing fibers are
preferably approximately circular cross-sections, they may also be
ellipsoid as shown in FIG. 1. Here, "radius" means the shortest
distance from the center of the fiber cross-section toward the
perimeter.
[0077] In the continuous fiber-reinforced molded resin of the
embodiment, preferably the occupying ratio of the secondary resin
of the two or more thermoplastic resins is higher than the
occupying ratio of the primary resin, in the interface region. This
state is illustrated in FIG. 7.
[0078] The void percentage in the "region of the outer peripheral
edge separated from the perimeter of the continuous reinforcing
fiber by 1/10 of the radius of a single continuous reinforcing
fiber, as observed at the interface between a single continuous
reinforcing fiber and the synthetic resin in a cross-section
perpendicular to the lengthwise direction of the continuous
reinforcing fiber" can be determined by the following formula:
Void percentage (%)=(area of voids in region of outer peripheral
edge separated from perimeter of continuous reinforcing fiber by
1/10 of radius of continuous reinforcing fiber)/(area of region of
outer peripheral edge separated from perimeter of continuous
reinforcing fiber by 1/10 of radius of continuous reinforcing
fiber).times.100,
after, for example, rotating a lengthwise-perpendicular
cross-section of a continuous reinforcing fiber of the continuous
fiber-reinforced molded resin cut to 1 cm-square with a band saw,
on a polishing table rotating at 100 rpm, with a force of 400
g/cm.sup.2 applied to the polishing surface, polishing it at
approximately 7 mL/min in the order: 10 minutes with #220
waterproof paper, 2 minutes with #400 waterproof paper, 5 minutes
with #800 waterproof paper, 10 minutes with #1200 waterproof paper,
15 minutes with #2000 waterproof paper, 15 minutes with 9 .mu.m
silicon carbide film particles, 15 minutes with 5 .mu.m alumina
film particles, 15 minutes with 3 .mu.m alumina film particles, 15
minutes with 1 .mu.m alumina film particles and 10 minutes with 0.1
.mu.m colloidal silica particles (BAIKALOX 0.1CR) with buffing
paper foamed polyurethane, while adding water, observing the
polished sample with a scanning electron microscope (SEM) and
performing image analysis with software such as ImageJ.
[0079] First, the void percentage is determined for the region of
the outer peripheral edge separated from the perimeter of an
arbitrary single continuous reinforcing fiber with an approximately
circular cross-section by a distance of 1/10 of the radius (the
"region of 1/10 of the diameter of a continuous reinforcing fiber"
will hereunder also be referred to simply as "interface region"),
and is observed for 100 arbitrary selected fibers. In the molded
article of this embodiment, preferably at least 10%, or 10 out of
every 100, more preferably at least 20%, even more preferably at
least 50%, yet more preferably at least 70% and most preferably at
least 90%, of the fibers have a void percentage of 10% or lower in
the region of 1/10 of the diameter of the continuous reinforcing
fiber, from the viewpoint of increasing the rigidity and strength
of the molded article.
[0080] In the molded article of the embodiment, the void percentage
in the region of 1/10 of the diameter of the continuous reinforcing
fiber is preferably 5% or lower, more preferably 2% or lower and
even more preferably 1% or lower, from the viewpoint of increasing
the rigidity and strength of the molded article.
[0081] In order to have at least 10% of 100 fibers with a void
percentage of 10% or lower in the region of 1/10 of the diameter of
the continuous reinforcing fiber, when the continuous reinforcing
fibers are glass fibers, for example, the sizing agent coated
during production of the glass fiber is selected to be one such
that the .mu.-drop formation coefficient between the sizing agent
and the synthetic resin is 10 or greater, and their compatibility
is satisfactory, while the molding method selected is either a
molding method allowing the die interior to be sealed during
molding, such as using an inlay die, or a molding method using a
double belt press with adjustable pressure, whereby leakage of the
resin is prevented and variation in the volume of the continuous
fiber-reinforced molded resin occupied by the glass fibers (Vf,
also known as the volume content) before and after molding is
reduced, and molding is carried out under temperature conditions
suited for the sizing agent.
[0082] The loss tangent in twisting mode can be calculated from the
peak top value of the loss tangent based on viscoelasticity
measurement of the continuous fiber-reinforced molded resin cut
with a band saw at 0.degree. and 90.degree. directions with respect
to the continuous fiber in twisting mode, under a nitrogen
atmosphere and with a constant temperature-elevating rate, for
example. The loss tangent of the continuous fiber-reinforced molded
resin of the embodiment in twisting mode is preferably 0.11 or
lower, more preferably 0.10 or lower, even more preferably 0.095 or
lower, even more preferably 0.090 or lower and most preferably
0.087 or lower.
[0083] The temperature at which the peak top of the loss tangent of
the continuous fiber-reinforced molded resin of the embodiment in
twisting mode is exhibited is preferably 78.degree. C. or higher,
more preferably 80.degree. C. or higher, even more preferably
82.degree. C. or higher and most preferably 84.degree. C. or
higher.
[0084] For the continuous fiber-reinforced molded resin of the
embodiment, preferably two peak tops emerge when the loss tangent
is plotted against each temperature, and the difference between the
two peak tops is preferably no greater than 80.degree. C., more
preferably no greater than 60.degree. C., even more preferably no
greater than 50.degree. C. and most preferably no greater than
35.degree. C.
[0085] In order to produce a continuous fiber-reinforced molded
resin having a loss tangent of 0.11 or lower, when the continuous
reinforcing fibers are glass fibers, for example, the sizing agent
coated during production of the glass fiber is selected to be one
such that the .mu.-drop formation coefficient between the sizing
agent and the synthetic resin is 10 or greater, and their
compatibility is satisfactory, while the molding method selected is
either a molding method allowing the die interior to be sealed
during molding, such as using an inlay die, or a molding method
using a double belt press with adjustable pressure, whereby leakage
of the resin is prevented and variation in the volume of the
continuous fiber-reinforced molded resin occupied by the glass
fibers (Vf, also known as the volume content) before and after
molding is reduced, and molding is carried out under temperature
conditions suited for the sizing agent.
[0086] The storage modulus in twisting mode can be calculated from
the peak top value of the storage modulus when the storage modulus
is plotted against each temperature, based on viscoelasticity
measurement of the continuous fiber-reinforced molded resin cut
with a band saw at 0.degree. and 90.degree. directions with respect
to the continuous fiber in twisting mode, under a nitrogen
atmosphere and with a constant temperature-elevating rate, for
example. The storage modulus of the continuous fiber-reinforced
molded resin of the embodiment in twisting mode is preferably 3.4
GPa or greater, more preferably 3.5 GPa or greater, even more
preferably 4.0 GPa or greater, yet more preferably 4.5 GPa or
greater, even yet more preferably 6.0 GPa or greater and most
preferably 7.0 GPa or greater.
[0087] For the continuous fiber-reinforced molded resin of the
embodiment, the storage modulus when measurement of the storage
modulus is carried out using a test piece cut in the 45.degree.
direction (diagonal direction) of the continuous fiber of the
continuous fiber-reinforced molded resin, is preferably at least
1.5 times, more preferably at least 1.6 times, even more preferably
at least 1.7 times and most preferably at least 1.9 times the
storage modulus when the measurement is carried out using test
pieces cut in the 0.degree. and 90.degree. directions.
[0088] For the continuous fiber-reinforced molded resin of the
embodiment, the storage modulus at 150.degree. C. is preferably at
least 25% and more preferably at least 26% of the maximum storage
modulus.
[0089] In viscoelasticity measurement of the continuous
fiber-reinforced molded resin of the embodiment in twisting mode,
the shear viscosity is preferably 330 MPas.sup.-1 or greater, more
preferably 470 MPas.sup.-1 or greater, even more preferably 500
MPas.sup.-1 or greater and most preferably 700 MPas.sup.-1 or
greater.
[0090] In order to produce a continuous fiber-reinforced molded
resin having a storage modulus of 3.4 GPa or greater in twisting
mode, when the continuous reinforcing fibers are glass fibers, for
example, the sizing agent coated during production of the glass
fiber is selected to be one such that the .mu.-drop formation
coefficient between the sizing agent and the synthetic resin is 10
or greater, and their compatibility is satisfactory, while the
molding method selected is either a molding method allowing the die
interior to be sealed during molding, such as using an inlay die,
or a molding method using a double belt press with adjustable
pressure, whereby leakage of the resin is prevented and variation
in the volume of the continuous fiber-reinforced molded resin
occupied by the glass fibers (Vf, also known as the volume content)
before and after molding is reduced, and molding is carried out
under temperature conditions suited for the sizing agent.
[0091] The bending storage modulus can be calculated from the
maximum storage modulus when the storage modulus is plotted against
each temperature, based on viscoelasticity measurement of the
continuous fiber-reinforced molded resin cut with a band saw at
0.degree. and 90.degree. directions with respect to the continuous
fiber in bending mode, under a nitrogen atmosphere and with a
constant temperature-elevating rate, for example. The bending
storage modulus of the continuous fiber-reinforced molded resin of
the embodiment is preferably 22 GPa or greater, more preferably 23
GPa or greater, even more preferably 25 GPa or greater, yet more
preferably 31 GPa or greater and most preferably 36 GPa or
greater.
[0092] In the continuous fiber-reinforced molded resin of the
embodiment, the bending storage modulus when measured at
150.degree. C. is preferably at least 76% of the bending storage
modulus at 30.degree. C.
[0093] For the continuous fiber-reinforced molded resin of the
embodiment, the bending storage modulus, when measurement of the
bending storage modulus is carried out using a test piece cut in
the 45.degree. direction (diagonal direction) of the continuous
fiber of the continuous fiber-reinforced molded resin, is
preferably at least 58%, more preferably at least 60% and even more
preferably at least 62% of the bending storage modulus when the
measurement is carried out using test pieces cut in the 0.degree.
or 90.degree. direction.
[0094] The tensile storage modulus and tensile loss tangent can be
calculated based on viscoelasticity measurement of the continuous
fiber-reinforced molded resin cut with a band saw at 0.degree. and
90.degree. directions with respect to the continuous fiber in
tension mode, under a nitrogen atmosphere and with a constant
temperature-elevating rate, for example. The tensile storage
modulus of the continuous fiber-reinforced molded resin of the
embodiment at 50.degree. C. is preferably 22 GPa or greater, more
preferably 25 GPa or greater, even more preferably 30 GPa or
greater, yet more preferably 32 GPa or greater, even yet more
preferably 35 GPa or greater and most preferably 40 GPa or
greater.
[0095] The maximum tensile loss tangent can be determined as the
maximum point on the plot of the loss tangent at each temperature,
obtained by the aforementioned measurement. The maximum loss
tangent of the continuous fiber-reinforced molded resin of the
embodiment is preferably 0.037 or lower, more preferably 0.035 or
lower and even more preferably 0.032 or lower.
[0096] For the continuous fiber-reinforced molded resin of the
embodiment, the temperature at which the values of the tensile
storage modulus and bending storage modulus are reversed is
preferably 95.degree. C. or higher, more preferably 100.degree. C.
or higher and even more preferably 105.degree. C. or higher, when
the tensile storage modulus and bending storage modulus are plotted
against each temperature.
[0097] When the tensile storage modulus and bending storage modulus
are plotted against each temperature for the continuous
fiber-reinforced molded resin of the embodiment, preferably the
following formula is satisfied:
{(Tensile storage modulus-bending storage modulus) at 30.degree.
C.}/{(bending storage modulus-tensile storage modulus) at
200.degree. C.}.gtoreq.1
[0098] In order to produce a continuous fiber-reinforced molded
resin having a bending storage modulus of 22 GPa or greater, when
the continuous reinforcing fibers are glass fibers, for example,
the sizing agent coated during production of the glass fibers is
selected to be one such that the .mu.-drop formation coefficient
between the sizing agent and the synthetic resin is 10 or greater,
and their compatibility is satisfactory, while the molding method
selected is either a molding method allowing the die interior to be
sealed during molding to inhibit flow of the resin, such as using
an inlay die, or a molding method using a double belt press with
adjustable pressure, whereby leakage of the resin is prevented and
variation in the volume of the continuous fiber-reinforced molded
resin occupied by the glass fibers (Vf, also known as the volume
content) before and after molding is reduced, and molding is
carried out while forming a satisfactory boundary interface, under
temperature conditions suited for the sizing agent.
[0099] The proportion of the region of the outer peripheral edge of
the continuous fiber-reinforced molded resin of the embodiment that
is occupied by each thermoplastic resin (the area ratio) can be
determined by cutting a cross-section in the thickness direction of
the continuous fiber-reinforced molded resin (a cross-section
perpendicular to the lengthwise direction of the continuous
reinforcing fibers), embedding it in an epoxy resin and polishing
it while taking care that the continuous reinforcing fibers are not
damaged, and then taking a mapping image of the cross-section with
a laser Raman microscope and identifying the type of resins in the
fiber-reinforced resin from the obtained image and spectrum, and
calculating the area of each by image processing with imageJ
software.
[0100] The distribution of the thermoplastic resins in the resin
region other than the interface region of the fiber-reinforced
molded resin can be determined, for example, by polishing a
cross-section (cross-section perpendicular to the lengthwise
direction of the continuous reinforcing fibers) of the continuous
fiber-reinforced molded resin that has been cut at a cross-section
in the thickness direction (a cross-section perpendicular to the
lengthwise direction of the continuous reinforcing fibers), with a
force of 125 g/cm.sup.2 on the polished surface, for 10 minutes
with #220 waterproof paper, 10 minutes with #1200 waterproof paper,
5 minutes with #2000 waterproof paper, 10 minutes with a silicon
carbide film having a particle size of 9 .mu.m, 10 minutes with an
alumina film having a particle size of 5 .mu.m, 5 minutes with an
alumina film having a particle size of 3 .mu.m, 5 minutes with an
alumina film having a particle size of 1 .mu.m, and 5 minutes with
colloidal silica having a particle size of 0.1 .mu.m (BAIKALOX
0.1CR) and comprising foam polyurethane buffing paper, while adding
water at about 7 mL/min for each polishing, subjecting the polished
sample to electron staining with phosphotungstic acid, and then
observing it with a scanning electron microscope (SEM) and
performing image analysis with software such as ImageJ. The
proportion occupied by the thermoplastic resin can be determined by
observing 10 arbitrary points and calculating the average.
[0101] Regarding the volume ratio between the continuous
reinforcing fibers and the synthetic resin, such as the
thermoplastic resin, since a higher Vf leads to a molded article
with higher strength, the continuous fiber-reinforced molded resin
of the embodiment is preferably one wherein the volume content Vf
of the continuous reinforcing fibers in the continuous
fiber-reinforced molded resin is 40% or higher, more preferably 45%
or higher, even more preferably 50% or higher, yet more preferably
55% or higher and most preferably 65% or higher. With
fiber-reinforced molded resins of the prior art, it has not been
possible to increase the void percentage and to increase the high
tensile stress (tensile strength) or flexural modulus (flexural
rigidity) of the molded article, even if the Vf is increased, but
with the continuous fiber-reinforced molded resin of the
embodiment, by reducing the void percentage, a synthetic resin
impregnation rate of 99% or higher in the continuous
fiber-reinforced resin composite, a tensile stress of 525 MPa or
higher and a flexural modulus of 27 GPa or greater are
simultaneously achieved at Vf 50%, and a synthetic resin
impregnation rate of 99% or higher, a tensile stress of 600 MPa or
higher and a flexural modulus of 35 GPa or greater are
simultaneously achieved at Vf 65%.
[0102] When the continuous reinforcing fibers are glass fibers, the
tensile stress of the continuous fiber-reinforced molded resin is
preferably 480 MPa or higher, more preferably 525 MPa or higher,
even more preferably 600 MPa or higher and most preferably 620 MPa
or higher, as the average value from testing in different
directions in which the glass fibers are essentially oriented. The
flexural modulus of the continuous fiber-reinforced molded resin is
preferably 22 GPa or greater, more preferably 27 GPa or greater,
even more preferably 30 GPa or greater and most preferably 35 GPa
or greater, as the average value from testing in different
directions in which the glass fibers are essentially oriented. The
tensile stress and flexural modulus are the values when the
continuous reinforcing fibers in the continuous fiber-reinforced
molded resin are oriented in essentially biplanar directions, being
average values for testing in biplanar directions parallel to the
continuous reinforcing fibers. For a three-directional material,
2/3 stress or rigidity is preferred, and for an n-directional
material, 2/n stress or rigidity is preferred.
[0103] When the continuous reinforcing fibers are glass fibers, the
value of the number of directions in which the glass fibers are
essentially oriented multiplied by the average value of the tensile
stress when testing in different directions in which the glass
fibers of the continuous fiber-reinforced molded resin are
essentially oriented, is preferably 960 MPa or higher, more
preferably 1050 MPa or higher, even more preferably 1200 MPa or
higher and most preferably 1240 MPa or higher. Also, the value of
the number of directions in which the glass fibers are essentially
oriented multiplied by the average value of the flexural stress
when testing in different directions in which the glass fibers of
the continuous fiber-reinforced molded resin are essentially
oriented, is preferably 1260 MPa or higher, more preferably 1400
MPa or higher, even more preferably 1600 MPa or higher and most
preferably 1700 MPa or higher. The value of the flexural modulus of
the continuous fiber-reinforced molded resin multiplied by the
number of directions in which the glass fibers are essentially
oriented is preferably 44 GPa or greater, more preferably 54 GPa or
greater, even more preferably 60 GPa or greater and most preferably
70 GPa or greater. The elasticity index of the continuous
fiber-reinforced molded resin, defined by the following
formula:
Elasticity index=(average value of elastic modulus in directions
parallel to the directions in which glass fibers are essentially
oriented.times.number of directions in which glass fibers are
essentially oriented)/(Vf.times.elastic modulus of glass
fibers)
is preferably 1.2 or higher, more preferably 1.3 or higher, even
more preferably 1.4 or higher, yet more preferably 1.5 or higher
and most preferably 1.58 or higher.
[Measurement by Acoustic Emission (AE) Method]
[0104] In measurement by the acoustic emission method, the
continuous fiber-reinforced molded resin of the embodiment has an
interlayer separation-induced breaking strength of preferably 40
MPa or higher and more preferably 50 MPa or higher.
[0105] Measurement by the acoustic emission method can be carried
out by attaching an AE sensor in an interlaminar shear test (JIS
K7078).
[Form of Continuous Fiber-Reinforced Molded Resin]
[0106] The form of the continuous fiber-reinforced molded resin is
not particularly restricted, and the following forms are possible.
For example, it may be in the form of a woven fabric or knitted
fabric, a braid or a pipe form of the reinforcing fibers in
combination with a resin, in the form of reinforcing fibers aligned
in one direction and composited with a resin, in the form of yarns
comprising reinforcing fibers and a resin aligned and molded in one
direction, or in the form of yarn comprising reinforcing fibers and
a resin that has been molded as a woven fabric or knitted fabric, a
braid or a pipe form.
[0107] The form of the intermediate material of the continuous
fiber-reinforced molded resin before molding may be combined
filament yarn comprising continuous reinforcing fibers and resin
fibers, coating yarn wherein the periphery of a continuous
reinforcing fiber bundle is covered with a resin, a tape-like form
with the resin impregnating the continuous reinforcing fibers
beforehand, continuous reinforcing fibers sandwiched between resin
films, resin powder adhering to continuous reinforcing fibers, a
continuous reinforcing fiber bundle as the core material surrounded
with a resin fiber braid, or a reinforcing fiber bundle impregnated
with a resin beforehand.
[Method for Producing Continuous Fiber-Reinforced Molded Resin
(Composite Material)]
[0108] The method for producing a continuous fiber-reinforced resin
composite material of this embodiment preferably comprises the
following steps:
[0109] a step of hot pressing continuous reinforcing fibers that
have addition of a sizing agent comprising a coupling agent,
binding agent and lubricating agent, with a thermoplastic resin
having terminal functional groups that are reactive with the
coupling agent, at above the melting point of the thermoplastic
resin, and
[0110] a step of cooling to below the melting point of the
thermoplastic resin to obtain a continuous fiber-reinforced resin
composite material as a molded article.
[0111] The amount of terminal functional groups of the continuous
fiber-reinforced resin composite material after hot pressing is
preferably less than the amount of terminal functional groups in
the thermoplastic resin before hot pressing from the viewpoint of
adhesion between the thermoplastic resin and the continuous
reinforcing fibers, the amount of terminal functional groups of the
continuous fiber-reinforced resin composite material after hot
pressing being preferably 90% or lower and more preferably 85% or
lower compared to the amount of terminal functional groups in the
thermoplastic resin before hot pressing.
[0112] From the viewpoint of reactivity of the coupling agent of
the sizing agent and the terminal functional groups of the
thermoplastic resin, the flow rate of the thermoplastic resin
during hot pressing is preferably 10% or lower, more preferably 8%
or lower, even more preferably 5% or lower and most preferably 3%
or lower.
[0113] When polypropylene is used as the thermoplastic resin, for
example, the reactive terminal functional groups are maleic acid
grafted onto the polypropylene resin as the main component.
[0114] The flow rate of the thermoplastic resin during hot pressing
can be determined as (weight of thermoplastic resin burrs produced
during hot pressing)/(weight of thermoplastic resin before hot
pressing).
[0115] The method of hot pressing is not particularly restricted,
but a hot pressing method using a double belt press is preferred
from the viewpoint of productivity. As the base material, the
reinforcing fibers and thermoplastic resin may be fed out from
multiple rolls and introduced into a double belt press apparatus,
or the reinforcing fibers and thermoplastic resin cut to a desired
size may be stacked in the desired number and introduced. A guide
sheet such as a TEFLON.sup.R sheet may also be introduced in front
of and behind the base material.
[0116] Another preferred hot pressing method is one carried out
with a die. Pressing with a die is not particularly restricted, and
any of the following methods are possible. For example, the base
material that is to compose the continuous fiber-reinforced molded
resin may be cut to match the desired molded article shape and
layered in the necessary number for the thickness of the target
product, and set in a manner conforming to the die shape.
[0117] Cutting of the base material may be carried out one at a
time, or any number may be stacked and cut together. From the
viewpoint of productivity, a plurality are preferably cut in a
stacked state. Any method may be used for cutting, examples of
which include methods using a water jet, blade press machine, hot
blade press machine, laser or plotter. A hot blade press machine is
preferred, for an excellent cross-sectional shape, and also better
handleability by welding of the edges when a multiple stack is cut.
A suitable cutting shape can be adjusted by repeated trial and
error, but it is preferably set by carrying out a simulation with
CAE (computer aided engineering), matching the die shape.
[0118] After the base material has been set in the die, the die is
closed and the material is pressed (compressed). The die is
adjusted to a temperature at or above the melting point of the
thermoplastic resin composing the continuous fiber-reinforced
molded resin, to melt the thermoplastic resin and shape it. The
mold clamping pressure is not particularly stipulated but is
preferably 1 MPa or higher and more preferably 3 MPa or higher. The
mold is clamped once for compression molding to remove the gas,
after which the die mold clamping pressure is released. From the
viewpoint of exhibiting strength, the compression molding time is
preferably as long as possible in a range that does not result in
heat degradation of the thermoplastic resin, and from the viewpoint
of productivity, it is preferably no longer than 2 minutes and more
preferably no longer than 1 minute.
[0119] In the production steps for a continuous fiber-reinforced
molded resin, the base material is set into a die and the die is
closed and pressurized, and after a predetermined time has elapsed,
it may be filled with a predetermined thermoplastic resin
composition that is injected in and molded, joining the
thermoplastic resin with the predetermined thermoplastic resin
composition to produce a hybrid molded article.
[0120] The timing for injection filling of the predetermined
thermoplastic resin composition will largely depend on the
interfacial strength between both thermoplastic resins. The timing
for injection filling of the predetermined thermoplastic resin
composition is preferably no longer than 30 seconds after the die
temperature has increased above the melting point and glass
transition temperature of the thermoplastic resin, after the base
material has been set in the die and the die has been closed.
[0121] The die temperature during injection filling of the
predetermined thermoplastic resin composition is preferably at or
above the melting point or glass transition temperature of the
thermoplastic resin composing the continuous fiber-reinforced
molded resin. More preferably, it is at or above the melting point
+10.degree. C. or the glass transition temperature +10.degree. C.,
even more preferably at or above the melting point +20.degree. C.
or the glass transition temperature +20.degree. C., and yet more
preferably at or above the melting point +30.degree. C. or the
glass transition temperature +30.degree. C., of the thermoplastic
resin composing the continuous fiber-reinforced molded resin.
[0122] In the hybrid molded article described above, the joining
section between the thermoplastic resin composing the continuous
fiber-reinforced molded resin and the thermoplastic resin
composition formed by injection molding preferably has an irregular
structure where both are combined.
[0123] For increasing the interfacial strength it is effective for
the die temperature to be at or above the melting point of the
injected thermoplastic resin composition, and for the resin to be
held at high pressure during injection molding, such as 1 MPa or
higher. In order to increase the interfacial strength, the holding
pressure is preferably 5 MPa or higher and more preferably 10 MPa
or higher.
[0124] Holding for a long holding pressure time, such as 5 seconds
or longer, preferably 10 seconds or longer and more preferably a
period until the die temperature falls below the melting point of
the thermoplastic resin composition, is preferred from the
viewpoint of increasing the interfacial strength.
[Injection Molding Resin]
[0125] The thermoplastic resin composition for injection molding to
be used for production of a hybrid molded article is not
particularly restricted so long as it is a thermoplastic resin
composition that can be used in ordinary injection molding.
[0126] Examples of such thermoplastic resin compositions include,
but are not limited to, resin compositions of one or mixtures of
two or more from among polyethylene, polypropylene, polyvinyl
chloride, acrylic resin, styrene-based resin, polyethylene
terephthalate, polybutylene terephthalate, polyallylate,
polyphenylene ether, modified polyphenylene ether resin, total
aromatic polyester, polyacetal, polycarbonate, polyetherimide,
polyethersulfone, polyamide-based resin, polysulfone, polyether
ether ketone and polyether ketone.
[0127] These thermoplastic resin compositions may also contain
various fillers.
[0128] Such fillers include staple fiber and long fiber materials
that are discontinuous reinforcing materials of the same types of
materials as the reinforcing fibers.
[0129] When glass staple fibers and long fibers are used as
discontinuous reinforcing materials, the same sizing agent may be
used as is coated onto the continuous reinforcing fibers composing
the continuous fiber-reinforced molded resin of the embodiment.
[0130] The sizing agent preferably comprises a (silane) coupling
agent, a lubricating agent and a binding agent. The type of
(silane) coupling agent, lubricating agent and binding agent used
may be the same as in the sizing agent for the continuous
reinforcing fibers described above.
[0131] A thermoplastic resin composition to be used in injection
molding is preferably similar to, and more preferably identical to,
the thermoplastic resin forming the continuous fiber-reinforced
molded resin, from the viewpoint of interfacial strength between
the continuous fiber-reinforced molded resin part and the
injection-molded thermoplastic resin composition part.
Specifically, when polyamide 66 fibers are used as the
thermoplastic resin forming the continuous fiber-reinforced molded
resin, it is preferred to use polyamide 66 for the resin material
of the thermoplastic resin composition for injection molding.
[0132] Other methods include a method of molding by setting the
base material in a die and compressing it with a double belt press
machine, or a method of setting a frame surrounding the four sides
of a set base material and compression molding it with a double
belt press machine, or a method of molding by preparing a heating
compression molding machine set to one or more temperatures and a
cooling compression molding machine set to one or more
temperatures, and loading the die in which the base material has
been set into each compression molding machine in order for
molding.
[Resin Impregnation Rate of Continuous Fiber-Reinforced Molded
Resin]
[0133] As shown in FIG. 2, the impregnation rate of the
thermoplastic resin in the continuous fiber-reinforced molded resin
is determined by the proportion of voids in a cross-section of the
continuous fiber-reinforced molded resin. Specifically, it is
calculated by cutting the continuous fiber-reinforced molded resin
at an arbitrary location, embedding it in an epoxy resin and
polishing it, and then using analysis software to analyze an image
obtained by optical microscope observation.
[0134] As shown in FIG. 6, the impregnation rate (%) is calculated
by the following formula:
Impregnation rate (%)={1-(void area/continuous reinforcing fiber
bundle area)}.times.100
with a predetermined area as 100%. From the viewpoint of strength
and outer appearance, the impregnation rate of the continuous
fiber-reinforced molded resin of the embodiment is preferably 98%
or higher, more preferably 99% or higher, even more preferably
99.5% or higher and most preferably 99.9% or higher.
[Continuous Reinforcing Fibers]
[0135] The continuous reinforcing fibers used may generally be any
ones used for continuous fiber-reinforced molded resins.
[0136] Continuous reinforcing fibers include, but are not limited
to, glass fibers, carbon fibers, plant fibers, aramid fibers,
ultra-high strength polyethylene fibers, polybenzazole fibers,
liquid crystal polyester fibers, polyketone fibers, metal fibers
and ceramic fibers.
[0137] Glass fibers, carbon fibers, plant fibers and aramid fibers
are preferred from the viewpoint of mechanical properties, thermal
properties and general utility, while glass fibers are preferred
from the viewpoint of productivity.
[0138] When glass fibers are selected as the continuous reinforcing
fibers, a sizing agent may be used, the sizing agent preferably
comprising a silane coupling agent, a lubricating agent and a
binding agent. If the sizing agent is one that binds strongly to
the resin coating the continuous reinforcing fibers, it will be
possible to obtain a continuous fiber-reinforced molded resin with
a low void percentage, and when a thermoplastic resin is used as
the synthetic resin, the sizing agent is preferably a sizing agent
for thermoplastic resins. A sizing agent for thermoplastic resins
is one such that when the continuous reinforcing fibers are raised
in temperature to 300.degree. C. at 30.degree. C./min in an
electric furnace and then returned to room temperature, the
rigidity of the continuous reinforcing fibers is greater than the
rigidity of the continuous reinforcing fibers before heating. When
a polyamide resin is selected as the synthetic resin, for example,
the sizing agent for thermoplastic resins must be selected as one
in which the silane coupling agent easily bonds with the terminal
carboxyl groups and amino groups of the polyamide resin. Specific
examples include .gamma.-aminopropyltrimethoxysilane and
epoxysilane.
[0139] It is necessary for the binding agent used to be a resin
having good wettability with or similar surface tension as the
polyamide resin. Specifically, a polyurethane resin emulsion or
polyamide resin emulsion, or a modified form of the same, may be
selected. It is necessary to use a lubricating agent that does not
inhibit the silane coupling agent and binding agent, an example of
which is carnauba wax.
[0140] From the viewpoint of impregnation of the thermoplastic
resin into the continuous reinforcing fibers, the sizing agent
preferably diffuses at least 50%, more preferably at least 70%,
even more preferably at least 80% and most preferably at least 90%,
in the thermoplastic resin during hot pressing. Diffusion of the
sizing agent can be determined for the molded article by dissolving
the matrix resin with a good solvent and performing XPS measurement
of the remaining reinforcing fibers, and when the matrix resin is a
polyamide, it is preferred to use HFIP or phenol.
[0141] If the sizing agent diffuses at least 90% in the
thermoplastic resin during hot pressing, and terminal groups that
are reactive with the coupling agent among the terminal functional
groups of the thermoplastic resin are decreased before and after
hot pressing, then the coupling agent has bonded with the terminal
functional groups of the thermoplastic resin.
[0142] The continuous reinforcing fibers may also be coated with a
catalyst that promotes reaction between the coupling agent and the
terminal functional groups of the thermoplastic resin, and when
glass fibers are selected as the continuous reinforcing fibers and
a polyamide resin is selected as the thermoplastic resin, for
example, examples of such a catalyst include phosphoric compounds
such as sodium hypophosphite, which promote bonding reaction
between the amino groups of the silane coupling agent and the
terminal carboxyl groups of the polyamide resin.
[Silane Coupling Agent]
[0143] A silane coupling agent is usually used as a surface
treatment agent for glass fibers, where it contributes to increased
interfacial bonding strength.
[0144] Examples of silane coupling agents include, but are not
limited to, aminosilanes such as
.gamma.-aminopropyltrimethoxysilane and
N-.beta.-(aminoethyl)-.gamma.-aminopropylmethyldimethoxysilane;
mercaptosilanes such as .gamma.-mercaptopropyltrimethoxysilane and
.gamma.-mercaptopropyltriethoxysilane; epoxysilanes; and
vinylsilanes and maleic acid. When a polyamide is used as the
synthetic resin it is preferred to use an aminosilane or maleic
acid, and when an epoxy resin is used as the synthetic resin it is
preferred to use an epoxysilane.
[Lubricating Agent]
[0145] A lubricating agent contributes to improved openability of
the glass fibers.
[0146] The lubricating agent used may be a common liquid or solid
lubricating material, selected depending on the purpose, and it may
be, but is not limited to, animal- or plant-based or mineral-based
waxes such as carnauba wax or lanolin wax; and surfactants such as
fatty acid amides, fatty acid esters, fatty acid ethers, aromatic
esters and aromatic ethers.
[Binding Agent]
[0147] A binding agent contributes to improved bundling and
increased interfacial bonding strength of glass fibers.
[0148] A binding agent that is used may be a polymer or
thermoplastic resin, depending on the purpose.
[0149] Polymers to be used as binding agents include, but are not
limited to, acrylic acid homopolymers, copolymers of acrylic acid
and other copolymerizable monomers, and salts of these with
primary, secondary or tertiary amines. Suitable examples to be used
include polyurethane-based resins synthesized from isocyanates such
as m-xylylene diisocyanate, 4,4'-methylenebis(cyclohexylisocyanate)
and isophorone diisocyanate, and polyester-based or polyether-based
diols.
[0150] An acrylic acid homopolymer has a weight-average molecular
weight of preferably 1,000 to 90,000 and more preferably 1,000 to
25,000.
[0151] Examples of copolymerizable monomers for formation of
copolymers of acrylic acid with other copolymerizable monomers
include, but are not limited to, one or more monomers with hydroxyl
and/or carboxyl groups, selected from the group consisting of
acrylic acid, maleic acid, methacrylic acid, vinylacetic acid,
crotonic acid, isocrotonic acid, fumaric acid, itaconic acid,
citraconic acid and mesaconic acid (where acrylic acid alone is
excluded). Preferred copolymerizable monomers are one or more
ester-based monomers.
[0152] Primary, secondary or tertiary amine salts of acrylic acid
homopolymers and copolymers include, but are not limited to,
triethylamine salts, triethanolamine salt and glycine salts. The
neutralization degree is preferably 20 to 90% and more preferably
40 to 60%, from the viewpoint of improving stability of the mixed
solution with other agents (such as silane coupling agents), and
reducing amine odor.
[0153] The weight-average molecular weight of a polymer of acrylic
acid forming a salt is not particularly restricted but is
preferably in the range of 3,000 to 50,000. It is preferably 3,000
or greater from the viewpoint of improved bundling of glass fibers,
and preferably 50,000 or lower from the viewpoint of improving the
properties as a composite molded article.
[0154] Examples of thermoplastic resins to be used as binding
agents include, but are not limited to, polyolefin-based resins,
polyamide-based resins, polyacetal-based resins,
polycarbonate-based resins, polyester-based resins, polyether
ketones, polyether ether ketones, polyether sulfones, polyphenylene
sulfide, thermoplastic polyetherimides, thermoplastic
fluorine-based resins, and modified thermoplastic resins obtained
by modifying such resins. The thermoplastic resin used as a binding
agent is preferably a thermoplastic resin and/or modified
thermoplastic resin of the same type as the resin covering the
periphery of the continuous reinforcing fibers, since this will
improve adhesion between the glass fibers and thermoplastic resin
after a composite molded article has been formed.
[0155] Especially in cases where adhesion between the continuous
reinforcing fibers and the thermoplastic resin covering them is to
be improved and a sizing agent is to be adhered to the glass fibers
as an aqueous dispersion, it is preferred to use a modified
thermoplastic resin as the thermoplastic resin of the binding
agent, from the viewpoint of reducing the ratio of emulsifier
component or limiting the need for an emulsifier.
[0156] A modified thermoplastic resin is one that has been
copolymerized with a different monomer component other than a
monomer component that can form the main chain of the thermoplastic
resin, having its hydrophilicity, crystallinity or thermodynamic
properties modified, in order to alter the properties of the
thermoplastic resin.
[0157] Examples of modified thermoplastic resins to be used as
binding agents include, but are not limited to, modified
polyolefin-based resins, modified polyamide-based resins and
modified polyester-based resins.
[0158] A modified polyolefin-based resin for the binding agent is a
copolymer of an olefin-based monomer such as ethylene or propylene
and a monomer that is copolymerizable with the olefin-based
monomer, such as an unsaturated carboxylic acid, and it can be
produced by a known method. It may be a random copolymer obtained
by copolymerization of an olefin-based monomer and an unsaturated
carboxylic acid, or a graft copolymer obtained by grafting an
unsaturated carboxylic acid onto an olefin.
[0159] Examples of olefin-based monomers include, but are not
limited to, ethylene, propylene and 1-butene. These may be used
alone, or two or more may be used in combination. Examples of
monomers that are copolymerizable with olefin-based monomers
include unsaturated carboxylic acids such as acrylic acid, maleic
acid, maleic anhydride, methacrylic acid, vinylacetic acid,
crotonic acid, isocrotonic acid, fumaric acid, itaconic acid,
citraconic acid and mesaconic acid, any of which may be used alone
or in combinations of two or more.
[0160] The copolymerization ratio of the olefin-based monomer and
the monomer that is copolymerizable with the olefin-based monomer,
is preferably 60 to 95 mass % of the olefin-based monomer and 5 to
40 mass % of the monomer that is copolymerizable with the
olefin-based monomer, and more preferably 70 to 85 mass % of the
olefin-based monomer and 15 to 30 mass % of the monomer that is
copolymerizable with the olefin-based monomer, with the total mass
of the copolymerization as 100 mass %. If the olefin-based monomer
is 60 mass % or greater, affinity with the matrix will be
satisfactory, and if the mass percentage of the olefin-based
monomer is 95 mass % or lower, the water dispersibility of the
modified polyolefin-based resin will be satisfactory and it will be
easier to achieve uniform application on the continuous reinforcing
fibers.
[0161] The modified polyolefin-based resin to be used as the
binding agent may have the modified groups such as carboxyl groups,
which have been introduced by copolymerization, neutralized with a
basic compound. Examples of basic compounds include, but are not
limited to, alkali compounds such as sodium hydroxide and potassium
hydroxide; ammonia; and amines such as monoethanolamine and
diethanolamine. The weight-average molecular weight of the modified
polyolefin-based resin to be used as a binding agent is not
particularly restricted, but it is preferably 5,000 to 200,000 and
more preferably 50,000 to 150,000. It is preferably 5,000 or
greater from the viewpoint of improved bundling of glass fibers,
and preferably 200,000 or lower from the viewpoint of emulsified
stability in water-dispersible form.
[0162] A modified polyamide-based resin to be used as a binding
agent is a modified polyamide compound having a hydrophilic group
such as a polyalkylene oxide chain or tertiary amine component
introduced into the molecular chain, and it can be produced by a
publicly known method.
[0163] When a polyalkylene oxide chain is to be introduced into the
molecular chain, it is produced, for example, by copolymerization
of a compound in which all or a portion of polyethylene glycol or
polypropylene glycol has been modified to a diamine or dicarboxylic
acid. For introduction of a tertiary amine component, it is
produced by copolymerization of aminoethylpiperazine,
bisaminopropylpiperazine or .alpha.-dimethylamino
.epsilon.-caprolactam, for example.
[0164] A modified polyester-based resin to be used as a binding
agent is a resin that is a copolymer of a polycarboxylic acid or
its anhydride and a polyol, and that has a hydrophilic group in the
molecular skeleton including the ends, and it can be produced by a
publicly known method.
[0165] Examples of hydrophilic groups include polyalkylene oxides,
sulfonic acid salts, carboxyl groups, and their neutral salts.
Polycarboxylic acids and their anhydrides include aromatic
dicarboxylic acids, sulfonic acid salt-containing aromatic
dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic
dicarboxylic acids and trifunctional or greater polycarboxylic
acids.
[0166] Examples of aromatic dicarboxylic acids include, but are not
limited to, phthalic acid, terephthalic acid, isophthalic acid,
orthophthalic acid, 1,5-naphthalenedicarboxylic acid,
2,6-naphthalenedicarboxylic acid and phthalic anhydride.
[0167] Examples of sulfonic acid salt-containing aromatic
dicarboxylic acids include, but are not limited to,
sulfoterephthalic acid salts, 5-sulfoisophthalic acid salts and
5-sulfoorthophthalic acid salts.
[0168] Examples of aliphatic dicarboxylic acids or alicyclic
dicarboxylic acids include, but are not limited to, fumaric acid,
maleic acid, itaconic acid, succinic acid, adipic acid, azelaic
acid, sebacic acid, dimer acid, 1,4-cyclohexanedicarboxylic acid,
succinic anhydride and maleic anhydride.
[0169] Examples of trifunctional or greater polycarboxylic acids
include, but are not limited to, trimellitic acid, pyromellitic
acid, trimellitic anhydride and pyromellitic anhydride.
[0170] From the viewpoint of increasing the heat resistance of the
modified polyester-based resin, preferably 40 to 99 mol % of the
total polycarboxylic acid component consists of aromatic
dicarboxylic acids. From the viewpoint of emulsified stability when
the modified polyester-based resin is in the form of an aqueous
dispersion, preferably 1 to 10 mol % of the total polycarboxylic
acid component is sulfonic acid salt-containing aromatic
dicarboxylic acids.
[0171] The polyol forming the modified polyester-based resin may be
a diol or a trifunctional or greater polyol.
[0172] Examples of diols include, but are not limited to, ethylene
glycol, diethylene glycol, polyethylene glycol, propylene glycol,
polypropylene glycol, polybutylene glycol, 1,3-propanediol,
1,4-butanediol, 1,6-hexanediol, neopentyl glycol,
polytetramethylene glycol, 1,4-cyclohexanediol,
1,4-cyclohexanedimethanol, bisphenol A, and their alkylene oxide
addition products. Trifunctional or greater polyols include
trimethylolpropane, glycerin and pentaerythritol.
[0173] The copolymerization ratio of the polycarboxylic acid or its
anhydride and the polyol forming the modified polyester-based resin
is preferably 40 to 60 mass % of the polycarboxylic acid or its
anhydride and 40 to 60 mass % of the polyol and more preferably 45
to 55 mass % of the polycarboxylic acid or its anhydride and 45 to
55 mass % of the polyol, with the total mass of the copolymerizing
component as 100 mass %.
[0174] The weight-average molecular weight of the modified
polyester-based resin is preferably 3,000 to 100,000 and more
preferably 10,000 to 30,000. It is preferably 3,000 or greater from
the viewpoint of improved bundling of the glass fibers, and
preferably 100,000 or lower from the viewpoint of emulsified
stability in water-dispersible form.
[0175] The polymer and thermoplastic resin used as the binding
agent may be used alone, or two or more may be used in
combination.
[0176] It is more preferred to use one or more polymers selected
from among acrylic acid homopolymers, copolymers of acrylic acid
and other copolymerizable monomers, and salts thereof with primary,
secondary and tertiary amines, at 50 mass % or greater or 60 mass %
or greater, with the entire amount of the binding agent as 100 mass
%.
[Composition of Sizing Agent for Glass Fibers]
[0177] When glass fibers are used as the continuous reinforcing
fibers, the sizing agent of the glass fibers preferably contains
0.1 to 2 mass % of a silane coupling agent, 0.01 to 1 mass % of a
lubricating agent and 1 to 25 mass % of a binding agent, and
preferably the components are diluted with water for adjustment of
the total mass to 100 mass %.
[0178] The content of the silane coupling agent in the sizing agent
for glass fibers is preferably 0.1 to 2 mass %, more preferably 0.1
to 1 mass % and even more preferably 0.2 to 0.5 mass %, from the
viewpoint of improving bundling of the glass fibers, increasing the
interfacial bonding strength and increasing the mechanical strength
of the composite molded article.
[0179] From the viewpoint of imparting sufficient lubricity, the
content of the lubricating agent in the sizing agent for glass
fibers is preferably 0.01 mass % or greater and more preferably
0.02 mass % or greater, and from the viewpoint of increasing the
interfacial bonding strength and increasing the mechanical strength
of the composite molded article it is preferably 1 mass % or lower
and more preferably 0.5 mass % or lower.
[0180] The content of the binding agent in the sizing agent for
glass fibers is preferably 1 to 25 mass %, more preferably 3 to 15
mass % and even more preferably 3 to 10 mass %, from the viewpoint
of controlling bundling of the glass fibers, increasing the
interfacial bonding strength and increasing the mechanical strength
of the composite molded article.
[Usage of Sizing Agent for Glass Fibers]
[0181] The sizing agent for glass fibers may be prepared into any
form such as an aqueous solution, a colloidal dispersion or an
emulsion using an emulsifier, depending on the usage, but it is
preferably in the form of an aqueous solution from the viewpoint of
increasing the dispersion stability of the sizing agent and
increasing the heat resistance.
[0182] Glass fibers used as continuous reinforcing fibers in the
continuous fiber-reinforced molded resin of the embodiment can be
continuously obtained by drying glass fibers produced using a known
method employing a roller-type applicator in a production process
for known glass fibers, and applying the sizing agent to the glass
fibers.
[0183] The sizing agent is applied at preferably 0.1 to 3 mass %,
more preferably 0.2 to 2 mass % and even more preferably 0.2 to 1
mass %, as the total mass of the silane coupling agent, lubricating
agent and binding agent, with respect to 100 mass % of the glass
fibers.
[0184] From the viewpoint of controlling bundling of the glass
fibers and increasing the interfacial bonding strength, the sizing
agent coverage is preferably 0.1 mass % or greater, as the total
mass of the silane coupling agent, lubricating agent and binding
agent with respect to 100 mass % of the glass fibers, and it is
also preferably 3 mass % or lower from the viewpoint of yarn
handleability.
[0185] When carbon fibers have been selected as the continuous
reinforcing fibers, the sizing agent preferably comprises a
coupling agent, a lubricating agent and a binding agent. The types
of sizing agent, lubricating agent and binding agent are not
particularly restricted, and publicly known agents may be used.
Specific materials that may be used include the materials mentioned
in Japanese Unexamined Patent Publication No. 2015-101794. The
coupling agent may be selected as one with good compatibility with
the hydroxyl groups present on the surfaces of the carbon fibers,
the binding agent may be selected as one having good wettability
with and similar surface tension to the selected synthetic resin,
and the lubricating agent may be selected as one that does not
inhibit the coupling agent and binding agent.
[0186] When other continuous reinforcing fibers are used, the type
and coverage of the sizing agent used on the glass fibers and
carbon fibers may be selected as appropriate depending on the
properties of the continuous reinforcing fibers, but the type and
coverage of the sizing agent are preferably for a sizing agent used
for carbon fibers.
[Continuous Reinforcing Fiber Form]
[0187] The continuous reinforcing fibers are preferably
multifilaments composed of a plurality of reinforcing fibers, with
the filament number preferably being 30 to 15,000, from the
viewpoint of handleability. The monofilament diameter of the
continuous reinforcing fibers is preferably 2 to 30 .mu.m, more
preferably 4 to 25 .mu.m, even more preferably 6 to 20 .mu.m and
most preferably 8 to 18 .mu.m, from the viewpoint of strength and
manageability.
[0188] The product RD of the monofilament diameter R (.mu.m) and
the density D (g/cm.sup.3) of the continuous reinforcing fibers is
preferably 5 to 100 .mu.mg/cm.sup.3, more preferably 10 to 50
.mu.mg/cm.sup.3, even more preferably 15 to 45 .mu.mg/cm.sup.3 and
yet more preferably 20 to 45 .mu.mg/cm.sup.3, from the viewpoint of
composite yarn manageability and molded article strength.
[0189] The density D can be measured using a densitometer. The
monofilament diameter (.mu.m) can be calculated by the following
formula:
Monofilament diameter=20.times. fineness/(.pi..times.number of
filaments.times.density))
based on the density (g/cm.sup.3) and fineness (dtex), and the
number of filaments.
[0190] To ensure that the product RD of the continuous reinforcing
fibers is within the predetermined range, commercially available
continuous reinforcing fibers may be used having the fineness
(dtex) and number of filaments appropriately selected for the
density of the continuous reinforcing fibers. For example, when
glass fibers are used as the continuous reinforcing fibers, the
density is about 2.5 g/cm.sup.3, and therefore a monofilament
diameter of 2 to 40 .mu.m may be selected. More specifically, when
the monofilament diameter of the glass fiber is 9 .mu.m, glass
fibers with a fineness of 660 dtex and a filament number of 400 may
be selected, for a product RD of 23. When the monofilament diameter
of the glass fibers is 17 .mu.m, glass fibers with a fineness of
11,500 dtex and a filament number of 2,000 may be selected, for a
product RD of 43. When carbon fibers are used as the continuous
reinforcing fibers, the density is about 1.8 g/cm.sup.3, and
therefore a monofilament diameter of 2.8 to 55 .mu.m may be
selected. Specifically, when the monofilament diameter of the
carbon fibers is 7.mu.m, carbon fibers with a fineness of 2,000
dtex and a filament number of 3,000 may be selected, for a product
RD of 13. When aramid fibers are used as the continuous reinforcing
fibers, the density is about 1.45 g/cm.sup.3, and therefore a
monofilament diameter of 3.4 to 68 .mu.m may be selected.
Specifically, when the monofilament diameter of the aramid fibers
is 12 .mu.m, aramid fibers with a fineness of 1,670 dtex and a
filament number of 1,000 may be selected, for a product RD of
17.
[0191] Continuous reinforcing fibers, such as glass fibers, are
produced by measuring and mixing raw glass and obtaining molten
glass in a melting furnace, spinning it into a glass filament,
coating it with a sizing agent, feeding it through a spinning
machine, and winding it up as Direct Wind Roving (DWR), a cake, or
twisted yarn. The continuous reinforcing fibers may be in any form,
but are preferably wound up into a yarn, cake or DWR for increased
productivity and production stability in the resin-coating step.
DWR is most preferred from the viewpoint of productivity.
[Synthetic Resin]
[0192] The synthetic resin composing the matrix resin of the
continuous fiber-reinforced molded resin of the embodiment may be a
thermoplastic resin or a thermosetting resin, but it is preferably
a thermoplastic resin from the viewpoint of the molding cycle and
recycling properties.
[Thermoplastic Resin]
[0193] The thermoplastic resin composing the continuous
fiber-reinforced molded resin of the embodiment may be of a single
type or a combination of more than one type. It is preferred to use
two or more thermoplastic resins from the viewpoint of adhesion
with the continuous fiber-reinforced resin. When two or more
thermoplastic resins are used, at the interface between a single
continuous reinforcing fiber and a synthetic resin in a
cross-section perpendicular to the lengthwise direction of the
continuous reinforcing fiber, in a region of the outer peripheral
edge separated from the perimeter of the continuous reinforcing
fiber by 1/10 of the radius of a single continuous reinforcing
fiber, the proportion of the two or more thermoplastic resins that
is occupied by resin other than the resin with the highest
occupying proportion of the entire resin region, is preferably
higher than the proportion occupied by the resin with the highest
occupying proportion of the entire resin region, from the viewpoint
of productivity and of interfacial strength between the reinforcing
fibers and the resin.
[0194] The thermoplastic resin has an absorption percentage of
preferably 0.1 wt % or greater, more preferably 0.3 wt % or
greater, even more preferably 0.5 wt % or greater, yet more
preferably 0.8 wt % or greater, even yet more preferably 1.0 wt %
or greater and most preferably 1.5 wt % or greater, from the
viewpoint of reactivity between the coupling agent and the terminal
functional groups of the thermoplastic resin. The absorption
percentage of the thermoplastic resin can be measured using a Karl
Fischer moisture analyzer.
[0195] A catalyst that promotes reaction between the coupling agent
and the terminal functional groups of the thermoplastic resin may
also be added to the thermoplastic resin, and when glass fibers are
selected as the continuous reinforcing fibers and a polyamide resin
is selected as the thermoplastic resin, for example, examples of
such a catalyst include phosphoric compounds such as sodium
hypophosphite, which promote bonding reaction between the amino
groups of the silane coupling agent and the terminal carboxyl
groups of the polyamide resin.
[0196] The content of the particulate additive in the thermoplastic
resin is preferably 30 ppm or lower, but from the viewpoint of
mechanical strength of the continuous fiber-reinforced resin
composite material it is more preferably 20 ppm or lower, even more
preferably 10 ppm or lower and most preferably 5 ppm or lower.
[0197] An example for the particulate additive in the thermoplastic
resin is carbon black.
[.mu.-Drop Formation Coefficient]
[0198] The .mu.-drop formation coefficient is an index of
compatibility between the resin and reinforcing fibers, the
.mu.-drop formation coefficient affecting not only the main
component of the resin but also affecting trace components in the
resin. The thermoplastic resin preferably has a .mu.-drop formation
coefficient of 10 or greater with the reinforcing fibers (assuming
a number of touches of 4). The .mu.-drop formation coefficient can
be calculated by the following formula, for example:
(.mu.-drop formation coefficient)={(number of .mu.-drops
formed)/(number of times resin touches reinforcing
fibers)}.times.10
after repeatedly touching the resin with the reinforcing fibers
using a composite material boundary interface evaluator (HM410,
product of Toei Sangyo Co., Ltd.) when the resin attaches to a
single reinforcing fiber filament, and counting the number of
.mu.-drops generated.
[Two or More Thermoplastic Resins]
[0199] The thermoplastic resin composing the matrix resin of the
continuous fiber-reinforced molded resin of the embodiment may also
consist of two or more types. Of the two or more thermoplastic
resins, from the viewpoint of heat resistance, preferably the resin
with the highest occupying proportion of the entire resin region
(the primary resin) preferably accounts for 85% to 99% of the total
area occupied by the two or more thermoplastic resins, while the
resin with the highest occupying proportion of the entire resin
region (the primary resin) of the two or more thermoplastic resins
is the resin with the highest melting point.
[0200] The difference between the melting point of the resin with
the highest melting point and the melting point of the resin with
the lowest melting point of the two or more thermoplastic resins is
preferably 35.degree. C. or higher, and more preferably 100.degree.
C. or higher. The types of thermoplastic resins in the continuous
fiber-reinforced molded resin can be identified by analyzing a
cross-section of the continuous fiber-reinforced molded resin with
a laser Raman microscope, and the melting point and glass
transition temperature of each thermoplastic resin can be
calculated from the composition of the resin, using a differential
scanning calorimeter (DSC). From the viewpoint of heat resistance,
the melting point of the thermoplastic resin mixture is preferably
the same as the melting point of the resin with the highest
occupying proportion of the entire resin region (the primary resin)
in the thermoplastic resin.
[0201] The difference between the melting peak temperature during
temperature increase and the crystallization peak temperature
during temperature decrease for the mixture of the two or more
thermoplastic resins forming the continuous fiber-reinforced molded
resin of the embodiment is preferably smaller than the difference
between the melting peak temperature during temperature increase
and the crystallization peak temperature during temperature
decrease of the resin with the highest occupying proportion of the
entire resin region (primary resin), among the resins of the two or
more thermoplastic resins, in order to obtain an excellent balance
between moldability and impregnation rate. The melting peak
temperature during temperature increase and the crystallization
peak temperature during temperature decrease can be calculated by
DSC.
[0202] Of the two or more thermoplastic resins forming the
continuous fiber-reinforced molded resin of the embodiment, the
bonding strength between at least one resin (secondary resin) other
than the resin with the highest occupying proportion of the entire
resin region (primary resin) and the continuous reinforcing fibers
is preferably larger than the bonding strength between the resin
with the highest occupying proportion of the entire resin region
(primary resin) and the continuous reinforcing fibers, from the
viewpoint of impregnating property and strength. The bonding
strength between each thermoplastic resin and the continuous
reinforcing fibers can be determined by a push-out test using a
nanoindenter.
[0203] Of the two or more thermoplastic resins forming the
continuous fiber-reinforced molded resin of the embodiment, the
difference in surface tension between at least one resin (secondary
resin) other than the resin with the highest occupying proportion
of the entire resin region (primary resin) and the continuous
reinforcing fibers is preferably larger than the difference in
surface tension between the resin with the highest occupying
proportion of the entire resin region (primary resin) and the
continuous reinforcing fibers, from the viewpoint of impregnating
property and strength. Of the two or more thermoplastic resins
forming the continuous fiber-reinforced molded resin of the
embodiment, the wettability of at least one resin (secondary resin)
other than the resin with the highest occupying proportion of the
entire resin region (primary resin) for the continuous reinforcing
fibers is preferably greater than the wettability of the resin with
the highest occupying proportion of the entire resin region
(primary resin) for the continuous reinforcing fibers, from the
viewpoint of impregnating property and strength. The difference in
surface tension and the wettability between each of the
thermoplastic resins and the continuous reinforcing fibers can be
evaluated by embedding a single continuous reinforcing fiber in the
thermoplastic resin melted on a hot plate, and determining the
length to which the thermoplastic resin is pulled on the continuous
fiber when the continuous reinforcing fiber has been pulled.
[0204] The melt viscosity of the mixture of the two or more
thermoplastic resins forming the continuous fiber-reinforced molded
resin of the embodiment is preferably the same as the melt
viscosity of the resin with the highest occupying proportion of the
entire resin region (primary resin) of the two or more
thermoplastic resins, for an excellent balance between strength and
impregnating property. The melt viscosity of the resin can be
measured using a twin-capillary rheometer.
[0205] The two or more thermoplastic resins forming the continuous
fiber-reinforced molded resin of the embodiment may be used in
pre-compounded form, depending on the form of the intermediate
material, or an intermediate material resin may be formed by dry
blending.
[Form of Thermoplastic Resin]
[0206] The form of the thermoplastic resin is not particularly
restricted, and it may be in the form of a film, pellets, fibers, a
plate, powder or a reinforcing fiber coating.
[Type of One or More Thermoplastic Resins]
[0207] Examples of thermoplastic resins include, but are not
limited to, polyolefin-based resins such as polyethylene and
polypropylene; polyamide-based resins such as polyamide 6,
polyamide 66 and polyamide 46; polyester-based resins such as
polyethylene terephthalate, polybutylene terephthalate and
polytrimethylene terephthalate; polyacetal-based resins such as
polyoxymethylene; polycarbonate-based resins; polyether-based
resins such as polyether ketone, polyether ether ketone, polyether
glycol, polypropylene glycol and polytetramethylene ether glycol;
polyether sulfones; polyphenylene sulfides; thermoplastic
polyetherimides; thermoplastic fluorine-based resins such as
tetrafluoroethylene-ethylene copolymers; polyurethane-based resins;
and acrylic-based resins, as well as modified thermoplastic resins
obtained by modifying any of the foregoing.
[0208] Of these thermoplastic resins, polyolefin-based resins,
polyamide-based resins, polyester-based resins, polyether-based
resins, polyether sulfones, polyphenylene sulfides, thermoplastic
polyetherimides and thermoplastic fluorine-based resins are
preferred, with polyolefin-based resins, modified polyolefin-based
resins, polyamide-based resins, polyester-based resins,
polyurethane-based resins and acrylic-based resins being more
preferred from the viewpoint of mechanical properties and general
utility, and polyamide-based resins and polyester-based resins
being even more preferred when the viewpoint of thermal properties
is also considered. Polyamide-based resins are even more preferred
from the viewpoint of durability against repeated load.
[Polyester-Based Resin]
[0209] A polyester-based resin is a polymer compound having a
--CO--O-- (ester) bond in the main chain.
[0210] Polyester-based resins include, but are not limited to,
polyethylene terephthalate, polybutylene terephthalate,
polytetramethylene terephthalate, poly-1,4-cyclohexylenedimethylene
terephthalate and polyethylene-2,6-naphthalene dicarboxylate.
[0211] A polyester-based resin may be a homopolyester or a
copolymerized polyester.
[0212] In the case of a copolymerized polyester, a suitable third
component is preferably copolymerized with a homopolyester, where
examples for the third component include, but are not limited to,
diol components such as diethylene glycol, neopentyl glycol and
polyalkylene glycol, and dicarboxylic acid components such as
adipic acid, sebacic acid, phthalic acid, isophthalic acid and
5-sodiumsulfoisophthalic acid.
[0213] A polyester-based resin employing a biomass resource-derived
starting material may also be used, where examples include, but are
not limited to, aliphatic polyester-based resins such as polylactic
acid, polybutylene succinate and polybutylene succinate adipate,
and aromatic polyester-based resins such as polybutylene adipate
terephthalate.
[Polyamide-Based Resin]
[0214] A polyamide-based resin is a polymer compound having a
--CO--NH-- (amide) bond in the main chain. Examples includes
aliphatic polyamides, aromatic polyamides and fully aromatic
polyamides, with aliphatic polyamides being preferred from the
viewpoint of high affinity with the reinforcing fibers and more
easily obtaining a reinforcing effect with the reinforcing
fibers.
[0215] The amount of carboxyl terminal groups in the polyamide
resin is preferably 65 .mu.mol/g or greater from the viewpoint of
adhesion between the resin and the reinforcing fibers, and it is
more preferably 70 .mu.mol/g or greater, even more preferably 75
.mu.mol/g or greater and yet more preferably 80 .mu.mol/g or
greater.
[0216] The amount of amino terminal groups in the polyamide resin
is preferably 40 .mu.mol/g or less from the viewpoint of adhesion
between the resin and the reinforcing fibers, and it is more
preferably 35 .mu.mol/g or less, even more preferably 30 .mu.mol/g
or less and yet more preferably 25 .mu.mol/g or less.
[0217] Examples of polyamide-based resins include, but are not
limited to, polyamides obtained by ring-opening polymerization of
lactams, polyamides obtained by self-condensation of
.omega.-aminocarboxylic acids, polyamides obtained by condensation
of diamines and dicarboxylic acids, and copolymers of the
foregoing.
[0218] Such polyamide-based resins may be used alone, or two or
more may be used in admixture.
[0219] Examples of lactams include, but are not limited to,
pyrrolidone, caprolactam, undecanelactam and dodecalactam. Examples
of .omega.-aminocarboxylic acids include, but are not limited to,
.omega.-amino fatty acids that are lactam compounds having the
rings opened with water. Two or more different lactam or
.omega.-aminocarboxylic acid monomers may also be condensed
together.
[0220] Examples of diamines (monomers) include, but are not limited
to, straight-chain aliphatic diamines such as hexamethylenediamine
or pentamethylenediamine; branched aliphatic diamines such as
2-methylpentanediamine or 2-ethylhexamethylenediamine; aromatic
diamines such as p-phenylenediamine or m-phenylenediamine; and
alicyclic diamines such as cyclohexanediamine, cyclopentanediamine
or cyclooctanediamine.
[0221] Examples of dicarboxylic acids (monomers) include, but are
not limited to, aliphatic dicarboxylic acids such as adipic acid,
pimelic acid and sebacic acid; aromatic dicarboxylic acids such as
phthalic acid and isophthalic acid; and alicyclic dicarboxylic
acids such as cyclohexanedicarboxylic acid. A diamine and
dicarboxylic acid as monomers may be condensed with either one each
alone, or two or more in combination.
[0222] Examples of polyamide-based resins include, but are not
limited to, polyamide 4 (poly .alpha.-pyrrolidone), polyamide 6
(polycaproamide), polyamide 11 (polyundecaneamide), polyamide 12
(polydodecaneamide), polyamide 46 (polytetramethylene adipamide),
polyamide 66 (polyhexamethylene adipamide), polyamide 610,
polyamide 612, polyamide 6T (polyhexamethylene terephthalamide),
polyamide 9T (polynonanemethylene terephthalamide) and polyamide 6I
(polyhexamethylene isophthalamide), as well as copolymerized
polyamides containing these as constituent components.
[0223] Examples of copolymerized polyamides include, but are not
limited to, copolymers of hexamethylene adipamide and hexamethylene
terephthalamide, copolymers of hexamethylene adipamide and
hexamethylene isophthalamide, and copolymers of hexamethylene
terephthalamide and 2-methylpentanediamine terephthalamide.
[Method for Producing Shaped Molded Article from Continuous
Fiber-Reinforced Composite Material]
[0224] A shaped molded article can be produced from the
fiber-reinforced composite material by a method including a step in
which the continuous fiber-reinforced resin composite material
produced by the method described above is heated at above the
melting point of the thermoplastic resin using an IR heater, for
example, and pressed using a die, and then cooled to a temperature
below the melting point of the thermoplastic resin and shaped.
[Thermosetting Resin]
[0225] Examples of thermosetting resins include, but are not
limited to, epoxy resins, phenol resins, melamine resins, urea
resins and unsaturated polyester resins. These thermosetting resins
may be used alone or in combinations of two or more.
[Uses of Continuous Fiber-Reinforced Molded Resin of the Embodiment
(Composite Material)]
[0226] The continuous fiber-reinforced molded resin of the
embodiment can be suitably used in structural materials for
aircraft, vehicles, construction materials, robots and
communication device housings.
[0227] Examples of uses for vehicles include, but are not limited
to, chassis/frames, suspensions, drive system components, interior
parts, exterior parts, functional parts and other parts.
[0228] Specifically, suitable uses include use in a part for a
steering axis, mount, sunroof, step, roof trimming, door trimming,
trunk, boot lid, bonnet, sheet frame, sheet back, retractor,
retractor support bracket, clutch, gear, pulley, cam, auger,
elasticity beam, buff ring, lamp, reflector, glazing, front-end
module, back door inner, brake pedal, handle, electrical material,
sound-absorbing material, door exterior, interior finishing panel,
instrument panel, rear gate, ceiling cover, sheet, seat framework,
wiper strut, EPS (Electric Power Steering), small motor, heat sink,
ECU (Engine Control Unit) box, ECU housing, steering gear box
housing, plastic housing, EV (Electric Vehicle) motor housing, wire
harness, in-vehicle meter, combination switch, small motor, spring,
damper, wheel, wheel cover, frame, sub-frame, side frame,
motorcycle frame, fuel tank, oil pan, intake manifold, propeller
shaft, driving motor, monocoque, hydrogen tank, fuel cell
electrode, panel, floor panel, outer plating panel, door, cabin,
roof, hood, valve, EGR (Exhaust Gas Recirculation) valve, variable
valve timing unit, connecting rod, cylinder bore, member (engine
mounting, front floor cloth, footwell cloth, seat cloth, inner
side, rear cloth, suspension, pillar lean force, front side, front
panel, upper, dash panel cloth, steering), tunnel, fasten insert,
crash box, crash rail, corrugate, roof rail, upper body, side rail,
braiding, door surround assembly, airbag member, body pillar, dash
two-pillar gusset, suspension tower, bumper, body pillar lower,
front body pillar, reinforcement (instrument panel, rail, roof,
front body pillar, roof rail, roof side rail, locker, door belt
line, front floor under, front body pillar upper, front body pillar
lower, center pillar, center pillar hinge, door outside panel),
side outer panel, front door window frame, MICS (Minimum Intrusion
Cabin System) bulk, torque box, radiator support, radiator fan,
water pump, fuel pump, electronic control throttle body, engine
control ECU, starter, alternator, manifold, transmission, clutch,
dash panel, dash panel insulator pad, door side impact protection
beam, bumper beam, door beam, bulkhead, outer pad, inner pad, rear
seat rod, door panel, door trimming board subassembly, energy
absorber (bumper, shock absorption), shock absorbing body, shock
absorption garnish, pillar garnish, roof side inner garnish, resin
rib, side rail front spacer, side rail rear spacer, seat belt
pretensioner, air bag sensor, arm (suspension, lower, hood hinge),
suspension link, shock absorption bracket, fender bracket, inverter
bracket, inverter module, hood inner panel, hood panel, cowl
louver, cowl top outer front panel, cowl top outer panel, floor
silencer, dump sheet, hood insulator, fender side panel protector,
cowl insulator, cowl top ventilator looper, cylinder head cover,
tire deflector, fender support, strut tower bar, mission center
tunnel, floor tunnel, radio core support, luggage panel, luggage
floor, accelerator pedal or accelerator pedal base.
[0229] The continuous fiber-reinforced molded resin of the
embodiment (composite material) may be in a rectangular solid
shape, for example, for communication device housing purposes.
[0230] The properties of a housing, being a member that requires
electromagnetic wave transparency, is an electric field shielding
property of preferably lower than 10 dB, more preferably lower than
5 dB and even more preferably lower than 0.1 dB in the frequency
band of 1 GHz, as measured by the KEC method. Continuous tempered
glass fibers may be used as the continuous reinforcing fibers with
this property.
[0231] The average wall thickness of the housing is preferably 1 mm
or smaller, more preferably 0.5 mm or smaller and most preferably
0.4 mm or smaller. For example, a housing of the desired thickness,
having low disorder of the continuous fibers and no generation of
voids, can be produced via a preform.
EXAMPLES
[0232] The present invention will now be explained in greater
detail by Examples and Comparative Examples, with the implicit
understanding that the invention is not limited to the Examples,
and various modifications may be implemented such as are within the
gist of the scope thereof.
[0233] The measuring methods used in the Examples and Comparative
Examples will be explained first.
[Average Void Percentage of Region of 1/10 of the Radius of the
Single Continuous Reinforcing Fiber from the Edge of the Single
Continuous Reinforcing Fiber]
[0234] The continuous fiber-reinforced molded resin was cut with a
band saw, and the cut test piece was polished using a polishing
machine (IS-POLISHER ISPP-1000 compact precision material
fabrication system (Ikegami Seiki Co., Ltd.)), with a pressure of
400 g/cm.sup.2 on the polishing surface. The polishing was carried
out for 10 minutes with #220 waterproof paper, 2 minutes with #400
waterproof paper, 5 minutes with #800 waterproof paper, 10 minutes
with #1200 waterproof paper, 15 minutes with #2000 waterproof
paper, 15 minutes with 9 .mu.m silicon carbide film particles, 15
minutes with 5 .mu.m alumina film particles, 15 minutes with 3
.mu.m alumina film particles, 15 minutes with 1 .mu.m alumina film
particles, and 10 minutes with 0.1 .mu.m colloidal silica particles
(BAIKALOX 0.1CR) with buffing paper foamed polyurethane, at
approximately 7 mL/min while adding water. The polished sample was
observed with an SEM (S-4700, by Hitachi High-Technologies Corp.),
and the void percentage in the region of 1/10 of the radius of the
single continuous reinforcing fiber was calculated from the
obtained image. Upon observing 100 arbitrarily selected continuous
reinforcing fibers, the average void percentage in the region of
1/10 of the radius of the single continuous reinforcing fiber, and
the proportion with a void percentage of 10% or lower, were
calculated.
[Impregnation Rate]
[0235] A cross-section was cut from the molded article and embedded
in an epoxy resin, and it was then polished while taking care not
to damage the continuous reinforcing fibers. Upon observation under
a microscope, the areas occupied by the continuous reinforcing
fiber bundle, synthetic resin and voids were each determined from
the image, and the void area percentage with respect to the
continuous reinforcing fiber bundle (total) area was determined by
calculation using the following formula:
Impregnation rate (%)={1-(void area/continuous reinforcing fiber
bundle area)}.times.100.
[Tensile Stress]
[0236] A test strip with a length of 70 mm, a width of 10 mm and a
wall thickness of 2 mm was cut out from the molded article, and the
tensile stress (MPa) of the test piece was measured using an
Instron universal testing machine at a speed of 5 mm/min, with
chucking at a spacing of 30 mm in the lengthwise direction, in a
thermostatic bath with an environment of 23.degree. C., 50% RH, and
150.degree. C., 50%.
[Flexural Stress and Flexural Modulus]
[0237] A test strip with a length of 100 mm, a width of 10 mm and a
wall thickness of 2 mm was cut out from the molded article, and a
3-point bending jig was used to measure the flexural stress (MPa)
and flexural modulus (GPa) with an Instron universal testing
machine, with the span set to 32 mm, at a speed of 1 mm/min and in
an environment of 23.degree. C., 50% RH.
[Measurement of Volume Ratio (Vf) of Reinforcing Fibers in
Continuous Fiber-Reinforced Resin and Quantity Ratio of Resin
Leaked During Molding]
[0238] A 2 g portion was cut out of the continuous fiber-reinforced
molded resin, and was placed in an electric furnace and heated at
650.degree. C. for 3 hours to burn off the resin. It was then
allowed to naturally cool to room temperature, and the mass of the
remaining glass fibers was measured to determine the proportion of
glass fibers and resin in the continuous fiber-reinforced molded
resin. Using the calculated proportion, it was divided by the
density to determine the volume ratio (Vf) of reinforcing fibers
with respect to the continuous fiber-reinforced molded resin. The
amount of resin leaked during molding was determined from the
amount of charged resin and the amount of resin in the continuous
fiber-reinforced molded resin after molding, and the amount of
leaked resin was divided by the amount of charged resin to
calculate the quantity ratio of leaked resin.
[Type and Occupying Ratio of Each Thermoplastic Resin of Two or
More Fiber-Reinforced Resins]
[0239] A cross-section of the continuous fiber-reinforced molded
resin in the thickness direction (cross-section perpendicular to
the lengthwise direction of the continuous reinforcing fibers) was
cut out at each of 5 arbitrary locations, embedded in an epoxy
resin, and polished while taking care that the continuous
reinforcing fibers were not damaged.
[0240] A mapping image of the cross-section was taken using a laser
Raman microscope (inViaQontor confocal Raman microscope, product of
Renishaw Co.), and the types of resins of the fiber-reinforced
resins were identified from the obtained image and spectrum. Each
area was also calculated by image processing using ImageJ, and the
occupying ratio of the resin in the region of 1/10 of the radius of
a single continuous reinforcing fiber from the edge of the single
continuous reinforcing fiber (the area ratio) was calculated. The
area ratio for each resin occupying the region of 1/10 of the
radius of the single continuous reinforcing fiber was calculated
for 10 arbitrary continuous reinforcing fibers in the
cross-section, and the average was calculated.
[Distribution of Thermoplastic Resin in Resin Regions Other than
Interface Region of Fiber-Reinforced Molded Resin]
[0241] The continuous fiber-reinforced molded resin was polished
with a polishing machine (IS-POLISHER ISPP-1000 compact precision
material fabrication system, Ikegami Seiki Co., Ltd.), with a force
of 125 g/cm.sup.2 on the polished surface. The polishing was
carried out for 10 minutes with #220 waterproof paper, 10 minutes
with #1200 waterproof paper, 5 minutes with #2000 waterproof paper,
10 minutes with 9 .mu.m silicon carbide film particles, 10 minutes
with 5 .mu.m alumina film particles, 5 minutes with 3 .mu.m alumina
film particles, 5 minutes with 1 .mu.m alumina film particles, and
5 minutes with 0.1 .mu.m colloidal silica particles (BAIKALOX
0.1CR) with buffing paper foamed polyurethane, at approximately 7
mL/min while adding water. The polished sample was subjected to
electron staining by immersion for 18 hours in a 5 wt % aqueous
solution of 12 tungsten(VI) phosphate n-hydrate, while taking care
not to allow collapse of the polished surface. After drying, the
distribution of the thermoplastic resin at 50 .mu.m.times.50 .mu.m
portions at 5 arbitrary locations was observed using a SEM (S-4700,
Hitachi High-Technologies Corp.), and the area of each was
calculated by image processing using imageJ. Based on the
distribution it was assessed whether each specific resin was evenly
dispersed or mixed in the resin regions other than the interface
region.
[Method of Measuring Loss Tangent of Continuous Fiber-Reinforced
Molded Resin]
[0242] A continuous fiber-reinforced molded resin with a 2 mm
thickness was cut with a band saw to a width of 5 mm and a length
of 60 mm in the 0.degree. and 90.degree. directions with respect to
the fiber direction, and a dynamic viscoelasticity measuring
apparatus (AresG2, TA Instruments) was used for measurement, under
a nitrogen atmosphere, in a measuring temperature range of
30.degree. C. to 250.degree. C. at a temperature-elevating rate of
5.0.degree. C./min, with an angular frequency of 10 rad/s and with
the deformation mode in twisting mode. The value of the loss
tangent and its temperature were obtained from the peak top value
of the graph plotting the loss tangent at each temperature, and
from its associated temperature. The value of the loss tangent was
used as the peak top at the low-temperature end.
[Surface Impact Test]
[0243] A test piece with a length of 60 mm, a width of 60 mm and a
wall thickness of 2 mm was cut out from the molded article and
tested with a high-speed impact tester (Shimadzu HYDRO SHOT
HITS-P10, Shimadzu Corp.) according to JIS K7211-2; 2006, using a
striker diameter of 20 mm.phi., a receiver diameter of 40 mm.phi.,
a test speed of 4.4 m/sec, a testing temperature of 23.degree. C.
and a testing number of n=5. A graph of test force with respect to
displacement was drawn, and the integral value until maximum impact
force was reached was calculated, recording the average value of 5
samples as the shock absorption energy.
[Method of Measuring Storage Modulus of Continuous Fiber-Reinforced
Molded Resin in Twisting Mode]
[0244] A continuous fiber-reinforced molded resin with a 2 mm
thickness was cut with a band saw to a width of 5 mm and a length
of 60 mm in the 0.degree. and 90.degree. directions or in a
45.degree. direction (diagonal direction) with respect to the fiber
direction, and a dynamic viscoelasticity measuring apparatus
(AresG2, TA Instruments) was used for measurement, under a nitrogen
atmosphere, in a measuring temperature range of 30.degree. C. to
250.degree. C. at a temperature-elevating rate of 5.0.degree.
C./min, with an angular frequency of 10 rad/s and with the
deformation mode in twisting mode. The value of the storage modulus
and its temperature were obtained from the peak top value of the
graph plotting the storage modulus at each temperature, and from
its associated temperature.
[Surface Impact Test]
[0245] A test piece with a length of 60 mm, a width of 60 mm and a
wall thickness of 2 mm was cut out from the molded article and
tested with a high-speed impact tester (Shimadzu HYDRO SHOT
HITS-P10, Shimadzu Corp.) according to JIS K7211-2; 2006, using a
striker diameter of 20 mm.phi., a receiver diameter of 40 mm.phi.,
a test speed of 4.4 m/sec, a testing temperature of 23.degree. C.
and a testing number of n=5. A graph of test force with respect to
displacement was drawn, and the maximum impact strength was
calculated as the average value of 5 samples.
[Method of Measuring Bending Storage Modulus of Continuous
Fiber-Reinforced Molded Resin]
[0246] A continuous fiber-reinforced molded resin with a 2 mm
thickness was cut with a band saw to a width of 5 mm and a length
of 60 mm in the 0.degree. and 90.degree. directions or in a
45.degree. direction (diagonal direction) with respect to the fiber
direction, and a dynamic viscoelasticity measuring apparatus
(EPLEXOR-SOON, ITS Japan, Inc.) was used for measurement, under a
nitrogen atmosphere, in a measuring temperature range of 25.degree.
C. to 250.degree. C. at a temperature-elevating rate of 3.0.degree.
C./min, with an oscillation frequency of 8 Hz and with the
deformation mode in bending mode, recording the maximum value as
the bending storage modulus. The storage modulus was obtained at
different temperatures.
[Method of Measuring Tensile Storage Modulus and Loss Tangent of
Continuous Fiber-Reinforced Molded Resin]
[0247] A continuous fiber-reinforced molded resin with a 2 mm
thickness was cut with a band saw to a width of 5 mm and a length
of 60 mm in the 0.degree. and 90.degree. directions with respect to
the fiber direction, and a dynamic viscoelasticity measuring
apparatus (EPLEXOR-SOON, ITS Japan, Inc.) was used for measurement,
under a nitrogen atmosphere, in a measuring temperature range of
20.degree. C. to 250.degree. C. at a temperature-elevating rate of
3.0.degree. C./min, with an oscillation frequency of 8 Hz and with
the deformation mode in tension mode, obtaining the storage modulus
at different temperatures. The maximum value between 20.degree. C.
and 200.degree. C. in the plot of the loss tangent at different
temperatures was recorded as the tensile loss tangent.
[Method of Measuring Melting Point and Crystallization Temperature
During Temperature Decrease for Thermoplastic Resin]
[0248] Using a DSC-60 by Shimadzu Corp., with a sample amount of
approximately 5 mg, a mixture of two or more thermoplastic resins,
or each one separately, was heated with atmospheric gas flowing at
30 mL/min and temperature increase of 10.degree. C./min, from room
temperature (25.degree. C.) to above the expected melting point, to
melting, after which the molten polyamide resin was cooled at
10.degree. C./min, and the crystallization temperature was recorded
as the peak top temperature among the observed exothermic peaks.
Next, the temperature was raised again at a speed of 10.degree.
C./min to above the melting point, and the melting point was
recorded as the peak top among the observed endothermic peaks.
[Measurement of Bonding Strength Between Reinforcing Fibers and
Each Thermoplastic Resin]
[0249] The continuous fiber-reinforced molded resin was cut to a
thickness of 30 .mu.m as a cross-section perpendicular to the
lengthwise direction of the continuous reinforcing fibers, and
polished while taking care that the continuous reinforcing fibers
were not damaged. Using the polished sample, the reinforcing fibers
were extruded out using a nanoindenter (iMicro, Nanomechenics,
Inc.) to measure the bonding strength between the reinforcing
fibers and the thermoplastic resin. The assessment was "G" when the
bonding strength between the reinforcing fibers and the resin
(secondary resin) other than the resin with the highest occupying
proportion of the entire resin region (primary resin), among the
thermoplastic resins, was stronger than the bonding strength
between the reinforcing fibers and the resin with the highest
occupying proportion of the entire resin region (primary resin),
and "P" when it was weaker.
[Measurement of Wettability and Surface Tension]
[0250] A single continuous reinforcing fiber was embedded in the
thermoplastic resin melted on a hot plate that had been heated to
280.degree. C., a 1 mm continuous reinforcing fiber was pulled at 1
mm/sec while observing it under a microscope, and the length to
which the thermoplastic resin was pulled by the continuous fiber
during that time was assessed. The wettability and surface tension
were assessed as "G" when the length to which the resin (secondary
resin) other than the resin with the highest occupying proportion
of the entire resin region (primary resin), among the thermoplastic
resins, was pulled by the reinforcing fibers was greater than the
length to which the resin with the highest occupying proportion of
the entire resin region (primary resin), among the thermoplastic
resins, was pulled by the reinforcing fibers, and "P" when it was
less.
[Measurement of Resin Melt Viscosity]
[0251] Measurement was performed using a twin-capillary rheometer
(Rosand Precision) at 280.degree. C., varying the shear rate to
100/s, 200/s, 400/s, 1000/s, 2000/s, 4000/s and 8000/s. For a shear
rate of 4000/s, an assessment of "G" was assigned when the melt
viscosity of the mixture of two or more thermoplastic resins was
4/5 to 5/4 times the viscosity of the resin with the highest
occupying proportion of the entire resin region, among the two or
more thermoplastic resins, and an assessment of "P" was assigned
otherwise.
[Measurement of Absorption Percentage of Thermoplastic Resin]
[0252] A Karl Fischer moisture analyzer (MKC610 by Kyoto
Electronics Co., Ltd.) was used to weigh out and measure 0.3 g of
thermoplastic resin under a nitrogen atmosphere.
[Measurement of Flow Rate During Hot Pressing of Thermoplastic
Resin]
[0253] This was determined by measuring the weight of the resin
that leaked out during molding and dividing it by the original
thermoplastic resin weight.
[Measurement of Volume Ratio of Reinforcing Fibers of Continuous
Fiber-Reinforced Resin Composite Material]
[0254] A 2 g portion was cut out of the continuous fiber-reinforced
resin composite material, and was placed in an electric furnace and
heated at 650.degree. C. for 3 hours to burn off the resin. It was
then allowed to naturally cool to room temperature, and the mass of
the remaining glass fibers was measured to determine the proportion
of glass fibers and resin in the continuous fiber-reinforced resin
composite material. Using the calculated proportion, it was divided
by the density to determine the volume ratio (Vf) of reinforcing
fibers with respect to the continuous fiber-reinforced resin
composite material.
[Measurement of Proportion of Sizing Agent Diffused into
Thermoplastic Resin]
[0255] After immersing 1 g of the continuous fiber-reinforced resin
composite material and 1 g of the continuous reinforcing fibers in
20 mL of hexafluoroisopropanol (HFIP), the mixture was stirred for
5 hours with a stirring roller to dissolve the thermoplastic resin.
The undissolved portion was washed twice with HFIP, again immersed
in HFIP, and stirred for 5 hours with a stirring roller. The
undissolved portion was washed twice with HFIP and vacuum dried,
and then an XPS (VersaProbe II, product of Ulvac-Phi, Inc.) was
used for measurement with an excitation source of mono.AlK.alpha.
20 kV.times.5 mA 100 W, an analysis size of 100 .mu.m.times.1.4 mm,
and with a photoelectron take-off angle.
[Measurement of Terminal Functional Group Amount]
[0256] After dissolving 15 mg of a sample in 1.5 mg of
D.sub.2SO.sub.4, .sup.1H-NMR (JEOL-ECZ500) measurement was
performed at room temperature.
[Measurement by Acoustic Emission (AE) Method]
[0257] Acoustic emission measurement was carried out using a
continuous fiber-reinforced resin composite material cut out to a
thickness of 2.0 mm, a length of 14 mm (7.times. the thickness) and
a width of 10 mm, in an interlaminar shear test (JIS K7078) in
which an AE sensor (AE-900 M) was mounted, with 10 mm between spans
(5.times. the thickness) and with the test speed set to 1 mm/min.
Analysis was performed with the preamp set to 34 dB, the threshold
value to 30 dB and the filter to 95 kHz-960 kHz, defining an AE
signal with an AE amplitude of lower than 50 dB and an AE signal
duration of shorter than 1000 .mu.s as corresponding to resin
damage, an AE signal with an AE amplitude of 60 dB or higher and an
AE signal duration of 1000 .mu.s or longer as corresponding to
interlayer separation, and an AE signal with an AE amplitude of 50
dB or higher and an AE signal duration of shorter than 1000 .mu.s
as corresponding to glass fiber damage.
[Measurement of .mu.-Drop Formation Coefficient]
[0258] The .mu.-drop formation coefficient was measured using a
composite material boundary interface property evaluator (HM410 by
Toei Sangyo Co., Ltd.), with the resin set in the heating furnace
unit and the furnace temperature set to 40.degree. C. below the
melting point of the resin, adhering the resin to each of the
individual reinforcing fibers set in the evaluator. When the resin
was unmelted and could not adhere onto the reinforcing fiber, the
furnace temperature was increased 10.degree. C. at a time until the
resin melted to adhere the resin onto the reinforcing fiber. The
resin fused onto the reinforcing fiber was touched 4 times to
adhere the resin and then allowed to stand for 1 minute, the number
of .mu.-drops generated was counted, and calculation was performed
using the following formula:
(.mu.-drop formation coefficient)={(number of .mu.-drops
generated/4}.times.10
[Vibration Fatigue Test]
[0259] A tensile impact dumbbell TypeS test piece conforming to
ASTM-D1822 was prepared, and the test was conducted with an
EHF-EB50kN-40L (RV) (product of Shimadzu Corp.), using a testing
temperature of 23.degree. C., a frequency of 20 Hz, a sine wave
waveform, a chuck distance of 35 mm and a minimum load set to 10%
load.
[Continuous Reinforcing Fibers]
[Glass Fibers (A)]
[0260] Glass fibers were produced in a filament number of 2000,
with a fineness of 11,500 dtex and with 0.45 mass % adhesion of the
sizing agent. The winding form was DWR and the mean monofilament
diameter was 17 .mu.m.
[0261] The glass fiber sizing agent was produced by copolymerizing
0.5 mass % of .gamma.-aminopropyltriethoxysilane (aminosilane)
KBE-903 (product of Shin-Etsu Chemical Co., Ltd.), 1 mass % of
carnauba wax, 2 mass % of polyurethane resin Y65-55 (product of
Adeka Corp.), 40 mass % of maleic anhydride, 50 mass % of methyl
acrylate and 10 mass % of methyl methacrylate, and using deionized
water for adjustment to 3 mass % of a copolymer compound with a
weight-average molecular weight of 20,000 and 3 mass % of the
copolymer compound aqueous solution.
[Glass Fibers B]
[0262] Glass fibers were produced in the same manner as glass
fibers (A), except for using a fineness of 2900 dtex, a filament
number of 800 and a mean monofilament diameter of 13 .mu.m.
[Glass Fibers C]
[0263] ER1200T-423 (Nippon Electric Glass Co., Ltd.)
[Thermoplastic Resin]
[0264] Polyamide resin A: Polyamide 66 (LEONA 1300S (Asahi Kasei
Corp.)), having a melting point of 265.degree. C., a difference
between melting peak temperature and crystallization peak
temperature during temperature decrease (Tm-Tc) of 53.degree. C., a
number of carboxyl terminal groups of 70 .mu.mol/g and an amino
terminal group content of 32 .mu.mol/g (Example 6-).
[0265] Polyamide resin B: Polyamide 6/12 (GRILON C CF6S
(EMS-Chemie, Japan), melting point: 130.degree. C.
[0266] Polyamide resin C: Polyamide 66 (LEONA 1402S (Asahi Kasei
Corp.))
or
[0267] Polyamide 6 (Examples 4-, 5-): GRILON BS/2 Natural
(EMS-Chemie, Japan), melting point: 225.degree. C.
[0268] Polyamide 6I (Example 5-): LEONA R16024 (Asahi Kasei Corp.),
glass transition temperature: 130.degree. C.
[0269] Polyamide 6T/6I (Example 5-): Trial product by Toyobo,
Ltd.
[0270] Polyethylene (PE) (Example 5-): SANTECH J240 (Asahi Kasei
Corp.), melting point: 125.degree. C.
[Polyamide Film]
[0271] The thermoplastic resins A and/or B were molded with a T-die
extruder (product of Soken Co., Ltd.) to obtain a film. The
thickness of the film was 100 .mu.m.
[Glass Cloth, Carbon Fiber Fabric]
[0272] A rapier loom (weaving width: 2 m) was used for weaving
using the glass fibers as the warp yarn and weft yarn, to produce a
glass cloth. The woven form of the obtained glass cloth was a plain
weave, the woven density was 6.5/25 mm and the basis weight was 600
g/m.sup.2.
[0273] Glass cloth (Example 5-): WFR 350 100BS6 (Nittobo Co.,
Ltd.)
[0274] Carbon fiber fabric: (Example 5-): Carbon fibers in a
filament number of 12,000 with a fineness of 8000 dtex, and having
polyvinylpyrrolidone adhering at 2.8 mass %, were produced and used
for weaving (plain weaving) with a rapier loom.
[Particulate Additive]
[0275] A master batch containing carbon black (Asahi Kasei Corp.)
was used as a particulate additive. The carbon black content was 3
wt %.
[Production of Continuous Fiber-Reinforced Molded Resin]
[0276] The molding machine used was a hydraulic molding machine
(Shoji Co.) with a maximum mold clamping force of 50 tons. A die
with an inlay structure was prepared to obtain a flat continuous
fiber-reinforced molded resin (200 mm length, 100 mm width, 2 mm
wall thickness).
[0277] The glass cloth and polyamide film were cut to the die
shape, layered in the prescribed number, and set in the die.
[0278] The internal temperature of the molding machine was raised
to 330.degree. C., and then the mold was clamped with a mold
clamping force of 5 MPa for compression molding. The molding time
was 1 minute after reaching 265.degree. C. as the melting point of
polyamide 66, and after quenching of the die, it was released and
the molded article was removed. The maximum temperature during
molding was 275.degree. C.
[Production with Double Belt Press Apparatus]
[0279] A double belt press apparatus (process system) was used as
the molding machine. Five glass cloths and 10 polyamide films were
fed out from rolls. The device heater temperature was 330.degree.
C., and cooling was by water-cooling. Pressurization was at a
pressure of 30 kN, and transport was at 0.2 m/min.
Example 1-1
[0280] Six glass cloths and seven polyamide resin A films were
stacked and molded. The molding time was 1 minute after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 285.degree.
C.
Example 1-2
[0281] Six glass cloths and seven polyamide resin A films were
stacked and molded. The temperature in the molding machine was set
to 300.degree. C., the molding time was 15 minutes after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 300.degree.
C.
Example 1-3
[0282] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 1-1, except that molding was for 30
seconds after reaching 265.degree. C. The maximum temperature
during molding was 280.degree. C.
Example 1-4
[0283] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 1-1, except that the polyamide film
consisted of a dry blend of polyamide resin A and polyamide resin B
(A:B=8:1).
Example 1-5
[0284] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 1-2, except that an epoxy resin was used
instead of the polyamide resin A film.
[0285] A glass cloth was produced using the glass fibers, after
adhering 0.3 mass % of 3-glycidoxypropyltrimethoxysilane (KBM-402,
Shin-Etsu Chemical Co., Ltd.), 1.5 mass % of an epoxy resin
emulsion and 0.2 mass % of carnauba wax, as the sizing agent. Six
of the glass cloths were layered and set in a die, 16 g of a
bisphenol A-type liquid epoxy resin (jER828 by Mitsubishi Chemical
Corp.) and 1.6 g of bisphenol A (4,4'-(propane-2,2-diyl)diphenol
were loaded in, and the temperature inside the molding machine was
set to 40.degree. C. for compression molding for 3 days at a mold
clamping pressure of 5 MPa, to obtain a continuous fiber-reinforced
molded resin.
Example 1-6
[0286] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 1-1, except that the number of glass
cloths was 5, and the number of polyamide resin A films was 10.
Comparative Example 1-1
[0287] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 1-1, except that glass fibers without
addition of a sizing agent were used.
Comparative Example 1-2
[0288] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 1-1, except that the glass fibers used
were adhered with a sizing agent that was 0.3 mass % of
3-glycidoxypropyltrimethoxysilane as a silane coupling agent, 1.5
mass % of an epoxy resin emulsion and 0.2 mass % of carnauba
wax.
Comparative Example 1-3
[0289] Evaluation was conducted in the same manner as Example 1-1,
for "Tepex Dynalite 101" by Bond Laminate Co. comprising a glass
cloth impregnated with polyamide 66.
Comparative Example 1-6
[0290] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 1-2, except that molding was with the
internal temperature of the molding machine set to 265.degree. C.
The maximum temperature during molding was 265.degree. C.
TABLE-US-00001 TABLE 1 Mean void Tensile Flexural Flexural
Impregnation Leaked resin percentage Percentage stress stress
modulus rate Vf quantity ratio (%) (%) (MPa) (MPa) (GPa) (%) (%)
(%) Example 1-1 0.5 87 649 950 36 100 65 0.1 Example 1-2 0.2 91 654
960 40 100 65 0.3 Example 1-3 2 60 620 850 33 99 65 0.1 Example 1-4
0.1 98 680 970 44 100 65 0.1 Example 1-5 4 30 580 830 30 98 65 0.1
Example 1-6 0.5 90 580 930 30 100 50 0.1 Comparative 50 2 180 300
12 85 65 0.1 Example 1-1 Comparative 30 5 350 400 18 90 65 0.1
Example 1-2 Comparative 25 8 380 560 23 100 47 Example 1-3
Comparative 30 8 440 530 23 97 65 0.3 Example 1-6
[0291] Based on Table 1, the continuous fiber-reinforced molded
resins of Examples 1-1 to 1-6 exhibited very high tensile stress,
flexural stress and flexural moduli, because they were continuous
fiber-reinforced resins in which at least 10% had a void percentage
in the region of 1/10 of the radius of a single continuous
reinforcing fiber from the edge of the single continuous
reinforcing fiber that was 10% or lower. Their physical properties
were much more satisfactory than the physical properties of a
molded article obtained using the commercially available
intermediate material of Comparative Example 1-3.
[0292] When using continuous reinforcing fibers that were not
coated with a sizing agent or continuous reinforcing fibers coated
with a sizing agent having poor compatibility with the resin, as in
Comparative Examples 1-1 and 1-2, the void percentage was larger
than 10% and the tensile stress, flexural stress and flexural
modulus were reduced.
[0293] When the molding temperature was low, as in Comparative
Example 1-6, the void percentage was larger than 10% and the
tensile stress, flexural stress and flexural modulus were
reduced.
Example 2-1
[0294] Six glass cloths and seven polyamide resin A films were
stacked and molded. The molding time was 1 minute after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 285.degree.
C.
Example 2-2
[0295] Six glass cloths and seven polyamide resin A films were
stacked and molded. The temperature in the molding machine was set
to 300.degree. C., the molding time was 10 minutes after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 300.degree.
C.
Example 2-3
[0296] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 2-1, except that molding was for 30
seconds after reaching 265.degree. C. The maximum temperature
during molding was 280.degree. C.
Example 2-4
[0297] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 2-1, except that the polyamide film was
a film of polyamide resin B.
Example 2-5
[0298] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 2-1, except that the number of glass
cloths was 5, and the number of polyamide resin A films was 10.
Example 2-6
[0299] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 2-2, except that the number of glass
cloths was 5, and the number of polyamide resin A films was 10.
Comparative Example 2-1
[0300] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 2-1, except that glass fibers without
addition of a sizing agent were used.
Comparative Example 2-2
[0301] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 2-6, except that the glass fibers used
were adhered with a sizing agent that was 0.3 mass % of
3-glycidoxypropyltrimethoxysilane as a silane coupling agent, 1.5
mass % of an epoxy resin emulsion and 0.2 mass % of carnauba
wax.
Comparative Example 2-3
[0302] Evaluation was conducted in the same manner as Example 2-1,
for "Tepex Dynalite 101" by Bond Laminate Co. comprising a glass
cloth impregnated with polyamide 66.
TABLE-US-00002 TABLE 2 Loss Loss Peak Shock tangent peak tangent
peak temperature absorption Leaked resin Loss temperature 1
temperature 2 Number difference energy Vf quantity ratio tangent
(.degree. C.) (.degree. C.) of peaks (.degree. C.) (J) (%) (%)
Example 2-1 0.072 103 1 26.21 65 0.1 Example 2-2 0.074 103 1 27.17
65 0.3 Example 2-3 0.090 91 1 25.40 65 0.1 Example 2-4 0.091 87 1
23.3 65 0.1 Example 2-5 0.087 84 103 2 19 24.50 50 0.1 Example 2-6
0.086 84 106 2 22 25.98 50 0.1 Comparative 0.15 53 1 10.02 65 0.1
Example 2-1 Comparative 0.13 75 150 2 75 15.90 50 0.1 Example 2-2
Comparative 0.12 77 167 2 90 16.08 50 Example 2-3
[0303] Based on Table 2, the continuous fiber-reinforced molded
resins of Examples 2-1 to 2-6 exhibited very high shock absorption
energy, because the loss tangent in twisting mode was 0.11 or
lower. Their physical properties were much more satisfactory than
the physical properties of a molded article obtained using the
commercially available intermediate material of Comparative Example
2-3.
[0304] When the loss tangent was high, as in the Comparative
Examples, the shock absorption energy was reduced.
Example 3-1
[0305] Six glass cloths and seven polyamide resin A films were
stacked and molded. The molding time was 1 minute after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 285.degree.
C.
Example 3-2
[0306] Six glass cloths and seven polyamide resin A films were
stacked and molded. The temperature in the molding machine was set
to 300.degree. C., the molding time was 10 minutes after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 300.degree.
C.
Example 3-3
[0307] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 3-1, except that molding was for 30
seconds after reaching 265.degree. C. The maximum temperature
during molding was 280.degree. C.
Example 3-4
[0308] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 3-1, except that the polyamide film was
a film of polyamide resin B.
Example 3-5
[0309] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 3-1, except that the number of glass
cloths was 5, and the number of polyamide resin A films was 10.
Example 3-6
[0310] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 3-2, except that the number of glass
cloths was 5, and the number of polyamide resin A films was 10.
Comparative Example 3-1
[0311] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 3-1, except that glass fibers without
addition of a sizing agent were used.
Comparative Example 3-2
[0312] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 3-6, except that the glass fibers used
were adhered with a sizing agent that was 0.3 mass % of
3-glycidoxypropyltrimethoxysilane as a silane coupling agent, 1.5
mass % of an epoxy resin emulsion and 0.2 mass % of carnauba
wax.
Comparative Example 3-3
[0313] Evaluation was conducted in the same manner as Example 3-1,
for "Tepex Dynalite 101" by Bond Laminate Co. comprising a glass
cloth impregnated with polyamide 66.
TABLE-US-00003 TABLE 3 Maximum Storage Storage storage modulus
modulus in Storage modulus in peak diagonal modulus Shear Impact
Leaked resin twisting temperature direction at 150.degree. C.
viscosity strength Vf quantity ratio mode (GPa) (.degree. C.) (GPa)
(GPa) (MPa s.sup.-1) (kN) (%) (%) Example 3-1 7.4 43 14.7 2.6 740
9.10 65 0.1 Example 3-2 7.7 43 15.5 2.9 770 9.25 65 0.3 Example 3-3
6.8 42 11.2 1.7 680 8.81 65 0.1 Example 3-4 7.2 40 14.1 2.3 720
9.05 65 0.1 Example 3-5 5.4 41 10.3 1.5 540 8.50 50 0.1 Example 3-6
5.3 42 10.3 1.4 530 8.50 50 0.1 Comparative 2.5 35 3.0 0.2 250 3.20
65 0.1 Example 3-1 Comparative 3.1 38 4.7 0.7 310 5.21 50 0.1
Example 3-2 Comparative 3.3 38 4.7 1.2 326 5.32 50 Example 3-3
[0314] Based on Table 3, the continuous fiber-reinforced molded
resins of Examples 3-1 to 3-6 exhibited very high impact strength,
because the storage modulus in twisting mode was 3.4 GPa or
greater. Their physical properties were much more satisfactory than
the physical properties of a molded article obtained using the
commercially available intermediate material of Comparative Example
3-3.
[0315] When the storage modulus in twisting mode was low, as in the
Comparative Examples, the impact strength was reduced.
Example 4-1
[0316] Five glass cloths and ten polyamide resin A films were
stacked and molded. The temperature in the molding machine was set
to 300.degree. C., the molding time was 10 minutes after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 300.degree. C.
The bending storage modulus at this time was 31 GPa, the bending
storage modulus at 150.degree. C. was 24 GPa (retention: 77%), the
bending storage modulus when cut diagonally was 20 GPa (retention:
64%), the tensile storage modulus at 50.degree. C. was 25 GPa, the
tensile loss tangent was 0.033, the temperature of tensile storage
modulus and bending storage modulus reversal was 115.degree. C.,
the value of {(tensile storage modulus-bending storage modulus) at
30.degree. C.}/{(bending storage modulus-tensile storage modulus)
at 200.degree. C.} was 2.3, and the impact strength was 8.50
kN.
Example 4-2
[0317] Six glass cloths and seven polyamide resin A films were
stacked and molded. The temperature in the molding machine was set
to 300.degree. C., the molding time was 10 minutes after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 300.degree. C.
The bending storage modulus at this time was 37 GPa, and the impact
strength was 9.25 kN.
Example 4-3
[0318] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 4-2, except that molding was for 30
seconds after reaching 265.degree. C. The maximum temperature
during molding was 280.degree. C. The bending storage modulus at
this time was 28 GPa, and the impact strength was 8.81 kN.
Example 4-4
[0319] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 4-2, except that the polyamide film was
a film of polyamide resin B. The bending storage modulus at this
time was 33 GPa, and the impact strength was 9.05 kN.
Example 4-5
[0320] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 4-1, except that molding was for 1
minute after reaching 265.degree. C. The maximum temperature during
molding was 285.degree. C. The bending storage modulus at this time
was 31 GPa, and the impact strength was 8.50 kN.
Example 4-6
[0321] Six glass cloths and seven polyamide resin A films were
stacked and molded. The molding time was 1 minute after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 285.degree. C.
The bending storage modulus at this time was 36 GPa, and the impact
strength was 9.10 kN.
Comparative Example 4-1
[0322] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 6, except that glass fibers without
addition of a sizing agent were used. The bending storage modulus
at this time was 15 GPa, and the impact strength was 3.20 kN.
Comparative Example 4-2
[0323] A continuous fiber-reinforced molded resin was obtained in
the same manner as Example 4-1, except that the glass fibers used
were adhered with a sizing agent that was 0.3 mass % of
3-glycidoxypropyltrimethoxysilane as a silane coupling agent, 1.5
mass % of an epoxy resin emulsion and 0.2 mass % of carnauba wax.
The bending storage modulus at this time was 20 GPa, and the impact
strength was 5.21 kN.
Comparative Example 4-3
[0324] Evaluation was conducted in the same manner as Example 4-1,
for "Tepex Dynalite 101" by Bond Laminate Co. comprising a glass
cloth impregnated with polyamide 66. The bending storage modulus at
this time was 20.8 GPa, the bending storage modulus at 150.degree.
C. was 15.7 GPa (retention: 75%), the bending storage modulus when
cut diagonally was 11.9 GPa (retention: 57%), the tensile storage
modulus at 50.degree. C. was 21 GPa, the tensile loss tangent was
0.038, the temperature of tensile storage modulus and bending
storage modulus reversal was 90.degree. C., the value of {(tensile
storage modulus-bending storage modulus) at 30.degree.
C.}/{(bending storage modulus-tensile storage modulus) at
200.degree. C.} was 0.57, and the impact strength was 5.32 kN.
[0325] The continuous fiber-reinforced molded resins of Examples
4-1 to 4-6 exhibited very high impact strength, because the bending
storage modulus in twisting mode was 22 GPa or greater. Their
physical properties were much more satisfactory than the physical
properties of a molded article obtained using the commercially
available intermediate material of Comparative Example 4-3.
[0326] When the bending storage modulus in twisting mode was low,
as in the Comparative Examples, the impact strength was
reduced.
Example 5-1
[0327] A thermoplastic resin film was produced using a dry blend of
PA66 and PA6/12 in a weight ratio of 8:1. The thickness of the film
was 100 .mu.m. After alternately laminating 11 films and 10 glass
cloths, they were molded. The PA6/12 was evenly dispersed in the
PA66 in the resin region other than the interface region with the
glass fibers.
Example 5-2
[0328] A continuous fiber-reinforced molded resin was produced in
the same manner as Example 5-1, except for using PA6 instead of
PA6/12. The PA6 was evenly dispersed in the PA66 in the resin
region other than the interface region with the glass fibers.
Example 5-3
[0329] A continuous fiber-reinforced molded resin was produced in
the same manner as Example 5-1, except for using PE instead of
PA6/12. The PE was evenly dispersed in the PA66 in the resin region
other than the interface region with the glass fibers.
Example 5-4
[0330] A continuous fiber-reinforced molded resin was produced in
the same manner as Example 5-1, except for using PA6I instead of
PA6/12. The PA6I was evenly dispersed in the PA66 in the resin
region other than the interface region with the glass fibers.
Example 5-5
[0331] A continuous fiber-reinforced molded resin was produced in
the same manner as Example 5-1, except that PA66 and PA6/12 were
dry blended in a weight ratio of 5:4. The PA6/12 was evenly
dispersed in the PA66 in the resin region other than the interface
region with the glass fibers.
Example 5-6
[0332] A continuous fiber-reinforced molded resin was produced in
the same manner as Example 5-1, except that the thermoplastic resin
film was produced using a mixture of PA66 and PA6/12 prekneaded
with a charging ratio (weight ratio) of 8:1 using a twin-screw
extruder (TEM26SS, Toshiba Machine Co., Ltd.). The PA6/12 was
evenly dispersed in the PA66 in the resin region other than the
interface region with the glass fibers.
Example 5-7
[0333] A continuous fiber-reinforced molded resin was produced in
the same manner as Example 5-1, except that a carbon fiber fabric
was used instead of a glass cloth. The PA6/12 was evenly dispersed
in the PA66 in the resin region other than the interface region
with the glass fibers.
Comparative Example 5-1
[0334] A continuous fiber-reinforced molded resin was produced in
the same manner as Example 5-1, except that the film was produced
using PA66 alone.
Comparative Example 5-2
[0335] A continuous fiber-reinforced molded resin was produced in
the same manner as Example 5-1, except for using PA6T/6I instead of
PA6/12. The PA6T/6I was evenly dispersed in the PA66 both in the
resin region other than the interface region with the glass fibers,
and in the interface region.
Comparative Example 5-3
[0336] A glass cloth was cut out to 19.5 cm.times.9.5 cm and
immersed in a solution of a polyamide emulsion adjusted to 30 mass
% with purified water (SEPOLSION PA200 by Sumitomo Seika Chemicals
Co., Ltd.), after which it was dried at 80.degree. C. for 1 hour
with a hot air circulation dryer to prepare a composite material.
The coverage of the PA6/12 polyamide emulsion solid component on
the glass cloth in the obtained composite material was 6 mass %.
This was then layered with a PA66 film to produce a continuous
fiber-reinforced molded resin in the same manner as Example 5-1.
With this Example, the PA6/12 was not evenly dispersed in the PA66,
but was present only in the interface region.
Comparative Example 5-4
[0337] A continuous fiber-reinforced molded resin was produced in
the same manner as Example 5-1, except that PA66 and PA6/12 were
dry blended in a weight ratio of 1:8. The PA66 was evenly dispersed
in the PA6/12 in the resin region other than the interface region
with the glass fibers.
[0338] The results for Examples 5-1 to 5-7 and Comparative Examples
5-1 to 5-4 are shown in Table 4.
TABLE-US-00004 TABLE 4 Example Example Example Example Example
Example 5-1 5-2 5-3 5-4 5-5 5-6 Occupying ratio of PA66:PA6/
PA66:PA6 = PA66:PE = PA66:PA6I = PA66:PA6/ PA66:PA6/ resin in
boundary 12 = 4:6 4:6 4:6 4:6 12 = 2:8 12 = 3:7 interface region
Occupying ratio of 8:1 8:1 8:1 8:1 5:4 8:1 resin in other resin
region Melting point difference 135 40 140 135 135 135 Tm - Tc 39
31 42 39 40 39 Bonding strength G G P G G G Wettability G G P G G G
Surface tension G G P G G G Resin melting point 265 265 265 265 250
265 Resin melt viscosity G G G G P G Impregnation rate (%) 99.5 99
99 99.5 99.5 99.5 Tensile stress 470 450 420 460 410 460 Flexural
stress 600 580 550 590 550 610 Flexural modulus 25 24 20 22 24 26
Tensile stress at 400 390 360 380 320 400 150.degree. C. Compar-
Compar- Compar- Compar- ative ative ative ative Example Example
Example Example Example 5-7 5-1 5-2 5-3 5-4 Occupying ratio of
PA66:PA6/ PA66:PA6T/ PA66:PA6/ PA66:PA6/ resin in boundary 12 = 4:6
6I = 8:1 12 = 1:9 12 = 1:9 interface region Occupying ratio of 8:1
8:1 10:0 1:8 resin in other resin region Melting poin difference
135 135 135 135 Tm - Tc 39 53 39 19 Bonding strength G P G P
Wettability G P G P Surface tension G P G P Resin melting point 265
265 265 130 Resin melt viscosity G G G Impregnation rate (%) 99.5
97 96 99 99 Tensile stress 800 380 320 420 420 Flexural stress 760
500 400 550 550 Flexural modulus 47 17 12 15 17 Tensile stress at
681 228 200 230 230 150.degree. C.
[0339] Judging from Table 4, for the continuous fiber-reinforced
molded resin of the embodiments, at the interface between a single
continuous reinforcing fiber of two or more types and the
thermoplastic resin in a cross-section perpendicular to the
lengthwise direction of the continuous reinforcing fiber, in a
region of the outer peripheral edge separated from the perimeter of
the continuous reinforcing fiber by 1/10 of the radius of a single
continuous reinforcing fiber, the proportion of the two or more
thermoplastic resins that was occupied by the resin (secondary
resin) other than the resin with the highest occupying proportion
of the entire resin region (primary resin), was higher than the
proportion occupied by the primary resin, as shown by Examples 5-1
to 5-7, but in the resin region other than that region of the outer
peripheral edge, each secondary resin other than the resin with the
highest occupying proportion of the entire resin region (primary
resin), of the two or more thermoplastic resins, was either evenly
dispersed or mixed, and therefore high tensile stress, flexural
stress, flexural modulus and high-temperature tensile stress were
exhibited. As shown by Comparative Example 5-1, on the other hand,
the adhesion between the reinforcing fibers and thermoplastic resin
was insufficient with only one type of thermoplastic resin, and the
tensile stress, flexural stress, flexural modulus and
high-temperature tensile stress were reduced. As shown by
Comparative Examples 5-2 and 5-4, even with two or more
thermoplastic resins, when the occupying ratio of the resin with
the highest occupying proportion of the entire resin region
(primary resin) among the two or more thermoplastic resins was
higher than the occupying ratio of the secondary resin, in the
region of the outer peripheral edge separated by 1/10 of the radius
of the single continuous reinforcing fiber from the perimeter of
the continuous reinforcing fibers of the two or more types,
adhesion between the reinforcing fibers and the thermoplastic resin
became insufficient, and the tensile stress, flexural stress,
flexural modulus and high-temperature tensile stress were reduced.
As shown in Comparative Example 3, even though secondary resin was
present other than the resin with the highest occupying proportion
of the entire resin region (primary resin), of the two or more
thermoplastic resins, in the region of the outer peripheral edge
separated by 1/10 of the radius of the single continuous
reinforcing fiber from the perimeter of the continuous reinforcing
fibers of the two or more types, the secondary resin was not evenly
dispersed or mixed in the resin region other than that region of
the outer peripheral edge, and therefore the high-temperature
tensile stress was reduced.
Example 6-1
[0340] Five glass cloths and 10 polyamide resin films were stacked
and molded using a double belt press apparatus. The absorption
percentage of the polyamide resin was 0.2 wt %. FIG. 3 shows a
photograph of an interface region in the obtained molded
article.
Example 6-2
[0341] Five glass cloths and ten polyamide resin films were stacked
and molded with a die. The molding time was 1 minute after reaching
265.degree. C. as the melting point of polyamide 66, and after
quenching of the die, it was released and the molded article was
removed. The maximum temperature during molding was 285.degree. C.
The absorption percentage of the polyamide resin was 0.2 wt %.
Example 6-3
[0342] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 6-1, except that the
polyamide resin film was dried with a vacuum dryer before molding.
The absorption percentage of the polyamide resin was 0.01 wt %.
Example 6-4
[0343] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 1, except that during
molding with the polyamide film, the polyamide resin and a carbon
black master batch were dry blended and molded for use as a
polyamide resin film. The absorption percentage of the polyamide
resin was 0.2 wt %. The carbon black content was 90 ppm. In the
Examples other than Example 6-4 and the Comparative Examples, no
carbon black particulate additive was added.
Example 6-5
[0344] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 6-1, except that the
polyamide 66 used had an amount of carboxyl terminal groups of 50
.mu.mol/g and an amount of carboxyl terminal groups of 30
.mu.mol/g. The absorption percentage of the polyamide resin was 0.2
wt %.
Example 6-6
[0345] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 6-1, except that the
polyamide 66 used had an amount of carboxyl terminal groups of 70
.mu.mol/g and an amount of amino terminal groups of 50 .mu.mol/g.
The absorption percentage of the polyamide resin was 0.2 wt %.
Example 6-7
[0346] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 6-1, except that the
thermoplastic resin used was obtained by using a biaxial kneader to
knead the polyamide 66 with 0.05 wt % sodium hypophosphite as a
catalyst to promote reaction between the silane coupling agent and
carboxyl terminal groups. The absorption percentage of the
polyamide resin was 0.2 wt %.
Example 6-8
[0347] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 6-1, except that 0.05 wt %
sodium hypophosphite was added to the sizing agent of the glass
fibers. The absorption percentage of the polyamide resin was 0.2 wt
%.
Example 6-9
[0348] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 6-2, except that a die open
in the longitudinal direction was used as the die. The absorption
percentage of the polyamide resin was 0.2 wt %.
Comparative Example 6-1
[0349] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 1, except that glass fibers
without addition of a sizing agent were used.
Comparative Example 6-2
[0350] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 6-1, except that the glass
fibers used were adhered with a sizing agent that was 0.3 mass % of
3-glycidoxypropyltrimethoxysilane as a silane coupling agent, 1.5
mass % of an epoxy resin emulsion and 0.2 mass % of carnauba wax.
FIG. 4 shows a photograph of an interface region in the obtained
molded article.
TABLE-US-00005 TABLE 5 Proportion with void Flow rate Proportion
Mean void percentage Tensile Flexural Flexural Impregnation during
of diffused percentage of 10% or stress stress modulus rate Vf
pressing sizing agent (%) lower (MPa) (MPa) (GPa) (%) (%) (%) (%)
Example 6-1 0.5 90 580 930 30 100 50 0.1 90 Example 6-2 0.5 90 580
930 30 100 50 0.1 90 Example 6-3 3.0 85 520 850 27 100 50 0.3 80
Example 6-4 6.0 75 490 750 25 100 50 3 80 Example 6-5 4.0 82 530
860 26 100 50 2 60 Example 6-6 4.0 82 530 860 26 100 50 2 60
Example 6-7 0.3 92 590 950 30 100 50 0.1 85 Example 6-8 0.3 92 590
950 30 100 50 0.1 85 Example 6-9 6.5 80 480 730 25 100 50 13 90
Comparative 50 2 180 300 12 85 50 0.1 -- Example 6-1 Comparative 30
5 350 400 18 90 50 0.1 20 Example 6-2
[0351] Based on Table 5, the continuous fiber-reinforced resin
composite materials of Examples 6-1 to 6-9 exhibited very high
tensile stress, flexural stress and flexural moduli due to
reactivity of the coupling agent with the terminal functional
groups in the thermoplastic resin.
[0352] When the absorption percentage of the thermoplastic resin
was low, as in Example 6-3, a reduction in physical properties was
found.
[0353] A reduction in physical properties was also found when the
particulate additive content was high, as in Example 6-4.
[0354] A reduction in physical properties was also found when the
carboxyl terminal group content of the polyamide resin was low, as
in Example 6-5.
[0355] A reduction in physical properties was also found when the
amino terminal group content of the polyamide resin was high, as in
Example 6-6.
[0356] When the flow rate of the thermoplastic resin was high
during pressing as in Example 6-9, the coupling agent and the
terminal functional groups in the thermoplastic resin failed to
thoroughly react, and a reduction in physical properties was
found.
[0357] In Comparative Example 6-1 which used continuous reinforcing
fibers not coated with a sizing agent, and Comparative Example 6-2
which used continuous reinforcing fibers coated with a sizing agent
containing a coupling agent with essentially no reactivity with the
terminal groups of the resin, the tensile stress, flexural stress
and flexural modulus were reduced.
Example 7-1
[0358] Five glass cloths using glass fibers A and ten films of
polyamide resin A were stacked and press molded with a die. The
molding time was 1 minute after reaching 265.degree. C. as the
melting point of polyamide 66, and after quenching of the die, it
was released and the molded article was removed. The maximum
temperature during molding was 285.degree. C. The A/E method was
used to measure the breaking strength of the molded article due to
interlayer separation.
Example 7-2
[0359] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 7-1, except that glass
fibers C were used as the continuous reinforcing fibers.
Example 7-3
[0360] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 7-2, except that molding was
carried out with a double belt apparatus.
Comparative Example 7-1
[0361] Evaluation was conducted in the same manner as Example 7-1,
for "Tepex Dynalite 101" by Bond Laminate Co. comprising a glass
cloth impregnated with polyamide 66.
TABLE-US-00006 TABLE 6 Interlayer separation breaking Tensile
Flexural Flexural Shock Shock strength stress stress modulus
absorption absorption (MPa) (MPa) (MPa) (GPa) energy (J) strength
(kN) Example 7-1 49.5 580 930 30 24.50 8.50 Example 7-2 53.2 590
940 30 25.50 8.70 Example 7-3 52.8 586 936 30 25.00 8.60
Comparative 29.3 380 560 23 16.08 5.32 Example 7-1
[0362] Based on Table 6, the continuous fiber-reinforced resin
composite materials of Examples 7-1 to 7-3 had higher breaking
strength due to interlayer separation and therefore exhibited much
higher tensile stress, flexural stress, flexural moduli and impact
strength, compared to Comparative Example 7-1.
Example 8-1
[0363] Five glass cloths using glass fibers A and ten films of
polyamide resin A were stacked and press molded with a die. The
molding time was 1 minute after reaching 265.degree. C. as the
melting point of polyamide 66, and after quenching of the die, it
was released and the molded article was removed. The maximum
temperature during molding was 285.degree. C. The .mu.-drop
formation coefficient between the glass fibers A and polyamide
resin A was 25.
Example 8-2
[0364] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 8-1, except that glass
fibers C were used. The .mu.-drop formation coefficient between the
glass fibers C and polyamide resin A was 27.
Comparative Example 8-1
[0365] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Example 8-1, except that a film of
polyamide resin C was used as the polyamide resin. The .mu.-drop
formation coefficient between the glass fibers A and polyamide
resin C was 3.
Comparative Example 8-2
[0366] A continuous fiber-reinforced resin composite material was
obtained in the same manner as Comparative Example 8-1, except that
glass fibers C were used as the glass fibers. The .mu.-drop
formation coefficient between the glass fibers C and polyamide
resin C was 3.
TABLE-US-00007 TABLE 7 Frequency of breakage in vibration .mu.-Drop
Tensile Flexural Flexural Shock Shock fatigue test formation stress
stress modulus absorption absorption at 250 MPa coefficient (MPa)
(MPa) (GPa) energy (J) strength (kN) (times) Example 8-1 25 580 930
30 24.50 8.50 36,000 Example 8-2 27 590 940 30 25.50 8.70 37,000
Comparative 3 420 730 20 17.76 6.11 1900 Example 8-1 Comparative 3
420 750 20 17.91 6.16 2000 Example 8-2
[0367] Based on Table 7, the continuous fiber-reinforced resin
composite materials of Examples 8-1 and 8-2 had higher .mu.-drop
formation coefficients, and therefore exhibited much higher tensile
stress, flexural stress, flexural moduli, impact strength and
long-term properties, compared to Comparative Examples 8-1 and
8-2.
Example 9
[0368] A smartphone housing with the shape shown in FIG. 12 was
fabricated. One glass cloth using glass fibers C was sandwiched by
polyamide resin A films and press molded.
[0369] The obtained molded article had a wall thickness of 0.4 mm,
dimensions of 135 mm in the lengthwise direction and 65 mm in the
widthwise direction, a lateral wall height of 5 mm, a tensile
strength of 550 MPa and a flexural modulus of 35 MPa in the
lengthwise direction, and a tensile strength of 530 MPa and a
flexural modulus of 33 MPa in the widthwise direction. As a result
of measuring the electric field shield property at a flat section
of the molded article by the KEC method, it was found to have
excellent electromagnetic wave transparency at 0 dB in the
frequency band of 1 GHz.
[0370] The outer appearance of the molded article was satisfactory
with no disorder of the fibers.
[0371] The tensile strength was measured according to JIS K7161.
The flexural modulus was measured according to JIS K7171. The
electric field shield property was measured by attaching a molded
article cut out to a 5 cm.times.5 cm square shape onto an aluminum
sample-anchoring jig using conductive tape, applying electrolysis
using an MA8602C electromagnetic wave shield property tester by
Anritsu Co. (KEC method), and measuring the electrolytic shield
characteristic at 1 GHz using an MS2661C spectrum analyzer by
Anritsu Co.
Example 10
[0372] The glass fibers C chopped to 3 mm were kneaded with
polyamide resin A using an HK-25D codirectional rotating twin-screw
kneading extruder (41D) .PHI.25 mm, L/D=41 (product of Parker
Corp.) and a metering unit (K-CL-24-KT20 weight-loaded twin-screw
feeder by K-Tron Co.), at a screw rotation speed of 175 rpm and a
supply rate of 5 kg/h, to obtain pellets. The pellets were used to
prepare a type A1, t4 mm molded multipurpose test piece conforming
to JIS K 7139, using an electric injection molding machine (NEX140
by Nissei Plastic Industrial Co., Ltd., 140 tf mold clamping
force/.PHI.40 screw diameter/full flight screw), under conditions
according to JIS K 7152-1. FIG. 10 shows an observational
photograph of the interface taken during the preparation.
Comparative Example 10
[0373] A molded article was fabricated in the same manner as
Example 10, except for using polyamide resin C as the polyamide
resin. FIG. 11 shows an observational photograph of the interface
taken during the preparation.
[0374] As shown in FIGS. 10 and 11, a satisfactory interface can be
formed when the .mu.-drop formation coefficient is 10 or greater
and compatibility between the glass fibers and resin is
satisfactory.
INDUSTRIAL APPLICABILITY
[0375] The continuous fiber-reinforced molded resin of the
embodiment is industrially useful as a reinforcing material for
materials that require a high level of mechanical properties, such
as structural parts for various machines and vehicles, and also as
a composite molded article material in thermoplastic resin
compositions. With the method for producing the continuous
fiber-reinforced resin composite material of the invention it is
possible to obtain a continuous fiber-reinforced resin composite
material that has high adhesive force and affinity at the
interfaces between the continuous reinforcing fibers and
thermoplastic resin and low voids in the interfaces, and that
exhibits sufficient strength.
REFERENCE SIGNS LIST
[0376] r Radius of continuous reinforcing fiber based on
approximately circular cross-section [0377] 1 Synthetic resin
[0378] 2 Continuous reinforcing fiber [0379] 3 Void [0380] 4
Continuous reinforcing fiber bundle [0381] 5 Region of outer
peripheral edge separated from the perimeter of a continuous
reinforcing fiber by 1/10 of the radius of the single continuous
reinforcing fiber, at the interface between the single continuous
reinforcing fiber and a thermoplastic resin, in a cross-section
perpendicular to the lengthwise direction of the continuous
reinforcing fiber. [0382] 6 Continuous reinforcing fiber [0383] 7
Resin (secondary resin) other than resin with the highest occupying
proportion of the entire resin region (primary resin) of two or
more thermoplastic resins [0384] 8 Resin with the highest occupying
proportion of the entire resin region (primary resin) of two or
more thermoplastic resins
* * * * *