U.S. patent application number 11/526003 was filed with the patent office on 2007-01-25 for process for producing chopped strands.
This patent application is currently assigned to Owens Corning Manufacturing Ltd.. Invention is credited to Kenichiro Masujima, Yoshiro Niino.
Application Number | 20070020446 11/526003 |
Document ID | / |
Family ID | 35056114 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070020446 |
Kind Code |
A1 |
Niino; Yoshiro ; et
al. |
January 25, 2007 |
Process for producing chopped strands
Abstract
It is to provide a process for producing chopped strands capable
of giving a molded product of which the mechanical strength and the
water resistance are not impaired and of which the color tone is
not deteriorated, capable of providing favorable dispersibility of
glass fibers in molding material pellets, and being excellent in
the releasability at the time of molding, and a fiber-reinforced
polyamide resin molding material using the chopped strands. Glass
fiber strands consisting of glass filaments spun from a bushing are
subjected to a surface treatment with a sizing agent comprising, in
terms of solid content, 100 parts by mass of an unsaturated
copolymer of maleic anhydride with an unsaturated monomer, from 10
to 90 parts by mass of a polyurethane resin and from 5 to 100 parts
by mass of a silane coupling agent, and then the obtained strands
are chopped.
Inventors: |
Niino; Yoshiro; (Tokyo,
JP) ; Masujima; Kenichiro; (Tokyo, JP) |
Correspondence
Address: |
C. IRVIN MCCLELLAND;OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Owens Corning Manufacturing
Ltd.
Tokyo
JP
|
Family ID: |
35056114 |
Appl. No.: |
11/526003 |
Filed: |
September 25, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP05/05434 |
Mar 24, 2005 |
|
|
|
11526003 |
Sep 25, 2006 |
|
|
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Current U.S.
Class: |
428/292.1 |
Current CPC
Class: |
C03C 25/285 20130101;
Y10T 428/249924 20150401; C03C 25/26 20130101; C08J 5/08 20130101;
C08J 2377/00 20130101; C03C 25/326 20130101 |
Class at
Publication: |
428/292.1 |
International
Class: |
D04H 1/00 20060101
D04H001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 25, 2004 |
JP |
2004-089995 |
Claims
1. A process for producing chopped strands, which comprises
subjecting glass fiber strands consisting of glass filaments spun
from a bushing to a surface treatment with a sizing agent
comprising, in terms of solid content, 100 parts by mass of an
unsaturated copolymer of maleic anhydride with an unsaturated
monomer, from 10 to 90 parts by mass of a polyurethane resin and
from 5 to 100 parts by mass of a silane coupling agent, and then
chopping the obtained strands.
2. The process for producing chopped strands according to claim 1,
wherein the sizing agent further contains an acrylic acid polymer
or a copolymer of acrylic acid with at least one monomer in an
amount of from 5 to 100 parts by mass in terms of solid content per
100 parts by mass of the unsaturated copolymer of maleic anhydride
with an unsaturated monomer.
3. The process for producing chopped strands according to claim 1,
wherein the sizing agent further contains a fluorescent brightening
agent.
4. The process for producing chopped strands according to claim 1,
wherein the number average molecular weight of the unsaturated
copolymer of maleic anhydride with an unsaturated monomer is at
least 5,000 and at most 100,000.
5. The process for producing chopped strands according to claim 1,
wherein the content of maleic anhydride in the unsaturated
copolymer of maleic anhydride with an unsaturated monomer is from
30 to 75 mol %.
6. The process for producing chopped strands according to claim 1,
wherein the unsaturated copolymer of maleic anhydride with an
unsaturated monomer is soluble in an alkaline aqueous medium.
7. The process for producing chopped strands according to claim 1,
wherein the polyol component constituting the polyurethane resin is
an aliphatic ether.
8. The process for producing chopped strands according to claim 1,
wherein the amount of the sizing agent attached is from 0.1 to 2
mass % in terms of solid content based on the glass fiber strands
having the sizing agent attached thereto.
9. The process for producing chopped strands according to claim 1,
wherein the glass fiber strands have an average filament diameter
of from 6 to 23 .mu.m, and each fiber strand contains from 100 to
4,000 glass filaments.
10. A fiber-reinforced polyamide molding material which is obtained
by kneading chopped strands obtained by the process as defined in
claim 1 and a polyamide resin, and which has a glass content of
from 5 to 70 mass %.
Description
TECHNICAL FIELD
[0001] The present invention relates to a process for producing
chopped strands which provide favorable dispersibility of glass
fibers in molding material pellets and are excellent in
releasability at the time of molding, and a fiber-reinforced
thermoplastic resin molding material of e.g. a polyamide resin
using the chopped strands.
BACKGROUND ART
[0002] Heretofore, a fiber polyamide molding material has been
known, which is obtained by kneading a molten polyamide resin as
the matrix resin with chopped strands obtained by cutting
reinforced fibers and extruding the kneaded product into fibers by
e.g. an extruder, and chopping them to obtain pellets.
[0003] The chopped strands used for the fiber-reinforced polyamide
molding material are required to be subjected to a surface
treatment with an appropriate sizing agent so as to improve the
mechanical strength and the water resistance of the
fiber-reinforced polyamide molding material to be obtained and thus
a molded product obtained by molding the molding material. In such
a case, it is essential to select a favorable sizing agent, and
various sizing agents therefor have been studied.
[0004] For example, Patent Document 1 discloses a thermoplastic
resin obtained by reinforcing a thermoplastic resin with glass
fiber chopped strands subjected to a surface treatment with a
copolymer of maleic anhydride with an unsaturated monomer and a
silane coupling agent. Patent Document 1 discloses remarkable
improvement in the mechanical strength and the water resistance of
the polyamide resin molding material to be obtained and a molded
product thereof.
[0005] However, there have had problems such that when a molded
product is prepared by using the thermoplastic resin reinforced by
glass fiber strands treated with the sizing agent, the molded
product tends to be colored yellow or the like, thus deteriorating
the color tone, the dispersion of the glass fibers in the molding
pellets tends to be poor, and the releasability from a mold when
the molded product is taken out at the time of injection molding
tends to be poor.
[0006] Patent Document 1: JP-A-60-44535
DISCLOSURE OF THE INVENTION
Object to Be Accomplished by the Invention
[0007] The present invention has been made to overcome the above
problems, and its object is to provide a process for producing
chopped strands capable of giving a molded product of which the
mechanical strength and the water resistance will not be impaired
and of which the color tone will not be deteriorated, capable of
providing favorable dispersibility of glass fibers in molding
material pellets and being excellent in the releasability at the
time of molding, and a fiber-reinforced polyamide resin molding
material using the chopped strands.
Means to Accomplish the Object
[0008] The present inventors have conducted extensive studies to
achieve the above object and as a result, have found that the above
object can be achieved by glass fiber chopped strands having glass
fiber strands consisting of glass filaments immediately after
spinning subjected to a surface treatment with a sizing agent
having a specific composition, and achieved the present
invention.
[0009] Namely, the present invention provides the following. [0010]
(1) A process for producing chopped strands, which comprises
subjecting glass fiber strands consisting of glass filaments spun
from a bushing to a surface treatment with a sizing agent
comprising, in terms of solid content, 100 parts by mass of an
unsaturated copolymer of maleic anhydride with an unsaturated
monomer, from 10 to 90 parts by mass of a polyurethane resin and
from 5 to 100 parts by mass of a silane coupling agent, and then
chopping the obtained strands. [0011] (2) The process for producing
chopped strands according to the above (1), wherein the sizing
agent further contains an acrylic acid polymer or a copolymer of
acrylic acid with at least one monomer in an amount of from 5 to
100 parts by mass in terms of solid content per 100 parts by mass
of the unsaturated copolymer of maleic anhydride with an
unsaturated monomer. [0012] (3) The process for producing chopped
strands according to the above (1) or (2), wherein the sizing agent
further contains a fluorescent brightening agent. [0013] (4) The
process for producing chopped strands according to any one of the
above (1) to (3), wherein the number average molecular weight of
the unsaturated copolymer of maleic anhydride with an unsaturated
monomer is at least 5,000 and at most 100,000. [0014] (5) The
process for producing chopped strands according to any one of the
above (1) to (4), wherein the content of maleic anhydride in the
unsaturated copolymer of maleic anhydride with an unsaturated
monomer is from 30 to 75 mol %. [0015] (6) The process for
producing chopped strands according to any one of the above (1) to
(5), wherein the unsaturated copolymer of maleic anhydride with an
unsaturated monomer is soluble in an alkaline aqueous medium.
[0016] (7) The process for producing chopped strands according to
any one of the above (1) to (6), wherein the polyol component
constituting the polyurethane resin is an aliphatic ether. [0017]
(8) The process for producing chopped strands according to any one
of the above (1) to (7), wherein the amount of the sizing agent
attached is from 0.1 to 2 mass % in terms of solid content based on
the glass fiber strands having the sizing agent attached thereto.
[0018] (9) The process for producing chopped strands according to
any one of the above (1) to (8), wherein the glass fiber strands
have an average filament diameter of from 6 to 23 .mu.m, and each
fiber strand contains from 100 to 4,000 glass filaments. [0019]
(10) A fiber-reinforced polyamide molding material which is
obtained by kneading chopped strands obtained by the process as
defined in any one of the above (1) to (9) and a polyamide resin,
and which has a glass content of from 5 to 70 mass %.
Effects of the Invention
[0020] According to the present invention, a novel process for
producing glass fiber chopped strands capable of giving a molded
product of which the mechanical strength and the water resistance
will not be impaired and of which the color tone will not be
deteriorate, capable of providing favorable dispersibility of glass
fibers in pellets and being excellent in releasability at the time
of molding, and a fiber-reinforced polyamide resin molding material
using the chopped strands, are provided.
BEST MODE FOR CARRYING OUT THE INVENTION
[0021] In the process for producing chopped strands of the present
invention, the glass fiber strands are subjected to a surface
treatment with a sizing agent comprising an unsaturated copolymer
of maleic anhydride with an unsaturated monomer, a polyurethane
resin and a silane coupling agent. The unsaturated monomer to be
copolymerized with maleic anhydride to form the unsaturated
copolymer is a monomer having at least two unsaturated bonds in its
molecule. It may, for example, be preferably a diene compound such
as butadiene, isoprene, chloroprene or 1,3-pentadiene. These
monomers may be used in combination of two or more types. Among
them, preferred is butadiene in view of the mechanical
strength.
[0022] With respect to the proportion of maleic anhydride and the
unsaturated monomer in the unsaturated copolymer, the proportion of
maleic anhydride is preferably from 30 to 75 mol %, particularly
preferably from 45 to 55 mol %. The copolymer having such a
proportion of maleic anhydride will be soluble in an alkaline
aqueous medium containing an alkaline substance (preferably an
alkali metal compound, ammonia or an amine). Such a copolymer will
form a salt in an alkaline aqueous medium, whereby it will be
stabilized in water, such being favorable.
[0023] Further, if the proportion of maleic anhydride in the
unsaturated copolymer is less than 30 mol %, the hydrophilicity of
the copolymer to be obtained will be low. In such a case, it is
possible to use an emulsifier so that the surface treatment of the
glass fiber strands is carried out with an emulsion, but the
adhesion to the matrix resin will decrease, and the mechanical
strength of the molded product will decrease, such being
unfavorable. Further, if the proportion of maleic anhydride exceeds
75 mol %, no further improvement in the mechanical strength of the
molded product will be achieved any more, but the amount of an
alkaline substance used for the neutralizing agent tends to be
large, and the water resistance will be rather impaired.
[0024] The copolymer of maleic anhydride with an unsaturated
monomer to be used in the present invention has a number average
molecular weight of at least 5,000 and at most 100,000, preferably
at least 10,000 and at most 80,000. If the average molecular weight
is less than 5,000, the molded product tends to have decreased
mechanical strength and water resistance, and on the contrary, if
it exceeds 100,000, the viscosity of the aqueous solution of the
copolymer tends to increase, which may cause problems such as
thread breakage at the time of production and a decrease in the
dispersibility of the glass fibers in pellets.
[0025] It is required that the sizing agent to be used in the
present invention contains a polyurethane resin, to improve the
color tone, to improve the dispersibility of the glass fibers in
pellets, and to improve the releasability at the time of injection
molding, without impairing the mechanical strength and the water
resistance of the molded product. As the polyurethane resin,
conventional one induced by a polymer polyol, an organic
diisocyanate and if necessary, a chain elongation agent and/or a
crosslinking agent, may be preferably used. The polyurethane resin
is used preferably as dispersed in water in the form of e.g. an
emulsion or a dispersion.
[0026] Specific examples of a preferred polymer polyol include
polyester polyols (such as polyethylene adipate diol, polybutylene
adipate diol, polyethylenebutylene adipate diol, polyneopentyl
adipate diol, polyneopentyl terephthalate diol, polycaprolactone
diol, polyvalerolactone diol and polyhexamethylenecarbonate diol);
and polyether polyols (such as polyethylene glycol, polypropylene
glycol, polyoxyethyleneoxypropylene glycol, polyoxytetramethylene
glycol, and ethylene oxide and/or polypropylene oxide addition
products of a bisphenol). The polymer polyol has a number average
molecular weight of usually from 500 to 6,000, preferably from 800
to 3,000.
[0027] Specific examples of a preferred organic diisocyanate
include aroamtic diisocyanates such as 2,4'- or
4,4'-diphenylmethane diisocyanate (MDI), 2,4- or 2,6-tolylene
diisocyanate (TDI), 4,4'-dibenzyl diisocyanate, 1,3- or
1,4-phenylene diisocyanate, 1,5-naphthylene diisocyanate and
xylylene diisocyanate; aliphatic diisocyanates such as ethylene
diisocyanate, hexamethylene diisocyanate (HDI) and lysine
diisocyanate; alicyclic diisocyanates such as isophorone
diisocyanate (IPDI) and 4,4'-dicyclohexylmethane diisocyanate; and
mixtures of two or more of them. Among them, particularly preferred
is MDI, TDI, HDI or IPDI.
[0028] The chain elongation agent and/or the crosslinking agent to
be used if necessary may, for example, be an active
hydrogen-containing compound having a number average molecular
weight of from 60 to 500, such as a polyhydric alcohol (such as a
dihydric alcohol such as ethylene glycol, propylene glycol,
1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol,
3-methylpentanediol, diethylene glycol, neopentyl glycol,
1,4-bis(hydroxymethyl)cyclohexane, 1,4-bis(hydroxyethyl)benzene or
2,2-bis(4,4'-hydroxycyclohexyl)propane; a trihydric alcohol such as
glycerol or trimethylolpropane; or a tetrahydric to octahydric
alcohol such as pentaerythritol, diglycerol, .alpha.-methyl
glucoside, sorbitol, xylite, mannite, dipentaerythritol, glucose,
fructose or sucrose); a polyhydric phenol (such as a polyhydric
phenol such as pyrogallol, catechol or hydroquinone; or a bisphenol
such as bisphenol A, bisphenol F or bisphenol S); water, or a
polyamine (such as an aliphatic polyamine (such as ethylenediamine,
hexamethylenediamine or diethylenetriamine), an alicyclic polyamine
(such as isophoronediamine or 4,4'-dicyclohexylmethane diamine), an
aromatic polyamine (such as 4,4'-diaminodiphenylmethane), an
aromatic alicyclic polyamine (such as xylylenediamine), hydrazine
or a derivative thereof).
[0029] The polyol component in the polyurethane resin is preferably
the above-described polyether represented by polyethylene glycol or
polypropylene glycol in view of the water resistance of the molded
product.
[0030] Further, the isocyanate component is preferably the
above-described aliphatic isocyanate represented by hexamethylene
diisocyanate or isophorone diisocyanate in view of reduced
yellowing of the molded product.
[0031] The silane coupling agent contained in the sizing agent to
be used in the present invention may be any silane coupling agent
used for the surface treatment of glass fibers. Specific examples
of a preferred silane coupling agent include aminosilanes such as
.gamma.-aminopropyltriethoxysilane,
N-.beta.-(aminoethyl)-.gamma.-aminopropyltrimethoxysilane,
N-.beta.-(aminoethyl)-N'-.beta.-(aminoethyl)-.gamma.-aminopropyltriethoxy-
silane and .gamma.-anilinopropyltrimethoxysilane; epoxysilanes such
as .gamma.-glycidoxypropyltrimethoxysilane and
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; vinylsilanes
such as vinyltrimethoxysilane and
N-.beta.-(N-vinylbenzylaminoethyl)-.gamma.-aminopropyltrimethoxysilane;
.gamma.-methacryloxypropyltrimethoxysilane,
.gamma.-chloropropyltrimethoxysilane and
.gamma.-mercaptopropyltrimethoxysilane. These coupling agents may
be used in combination of two or more types.
[0032] The silane coupling agent is preferably the monoaminosilane
or the diaminosilane among them, and particularly preferred is the
monoaminosilane in view of the color tone.
[0033] The sizing agent to be used in the present invention
preferably contains, in addition to the above components, an
acrylic acid polymer or a copolymer of acrylic acid with at least
one monomer. In such a case, the mechanical strength will be
improved while deterioration of the color tone of the molded
product will be suppressed, and further, particularly favorable
dispersibility of the glass fibers in the molding material will be
achieved, and the releasability from a mold at the time of
production of the molded product will be improved.
[0034] Preferred examples of the monomer to be used for production
of the copolymer with acrylic acid include ethylene, propylene,
isobutylene, styrene, .alpha.-methylstyrene, vinyl acetate,
butadiene, isoprene, chloroprene, an acrylic ester and a
methacrylic ester. These monomers may be used in combination of two
or more types.
[0035] Further, the sizing agent of the present invention
preferably contains a fluorescent brightening agent with a view to
improving the color tone of the molded product. The fluorescent
brightening agent may be a benzoxazole, triazole, coumarin,
pyrazoline, styryl or naphthalimide type. Among them, a benzoxazole
type or a triazole type is more preferred. The fluorescent
brightening agent is contained preferably in an amount of from
0.001 to 0.1 part by mass per 100 parts by mass of the glass fiber
strands treated with the sizing agent. If the amount is less than
0.001 part by mass, no effect of improving the color tone of the
molded product will be achieved. Further, if it exceeds 0.1 part by
mass, such is economically unfavorable and further, the molded
product tends to be dark or reddish particularly at a high
processing temperature.
[0036] With respect to the contents of the unsaturated copolymer of
maleic anhydride with an unsaturated monomer, the polyurethane
resin and the silane coupling agent in the sizing agent to be used
in the present invention, in terms of solid content, the proportion
of the polyurethane resin is from 10 to 90 parts by mass,
preferably from 20 to 80 parts by mass, and the proportion of the
silane coupling agent is from 5 to 100 parts by mass, preferably
from 20 to 50 parts by mass, per 100 parts by mass of the
unsaturated copolymer. Such proportions are preferred in view of
the mechanical strength of the molded product, the color tone of
the molded product, the dispersibility of the glass fibers in
pellets and favorable releasability at the time of injection
molding. If the proportion of the polyurethane resin is higher than
90 parts by mass, the molded product tends to be inferior in the
mechanical strength, and if it is lower than 10 parts by mass, the
molded product tends to be inferior in the color tone and further,
the dispersibility and the releasability tend to be poor. Further,
if the proportion of the silane coupling agent is lower than 5
parts by mass, the molded product tends to be inferior in the
mechanical strength, and if it is higher than 100 parts by mass,
the mechanical strength and the durability will rather decrease and
further, the color tone tends to be poor.
[0037] Further, in a case where the sizing agent contains the
polyacrylic acid or the copolymer of acrylic acid with at least one
monomer, the polymer is contained preferably in an amount of from 5
to 100 parts by mass, preferably from 10 to 50 parts by mass, in
terms of solid content, per 100 parts by mass of the unsaturated
copolymer of maleic anhydride with an unsaturated monomer. If the
content of the polymer exceeds 100 parts by mass, the molded
product tends to be inferior in the mechanical strength, and if it
is less than 5 parts by mass, the color tone tends to be poor and
in addition, some of the glass fibers in the molding material will
not be dispersed, thus impairing the releasability.
[0038] Further, for the sizing agent of the present invention, as a
surfactant, a nonionic surfactant such as an ethylene oxide
propylene oxide copolymer, a synthetic alcohol type, a natural
alcohol type, a fatty acid ester type or a distyrenated phenol type
may be used.
[0039] Further, the sizing agent of the present invention may
contain, in addition to the above components, a fatty acid amide or
the like as a lubricant, or a quaternary ammonium salt. As the
fatty acid amide, a dehydration condensate of a polyethylene
polyamine such as diethylenetriamine, triethylenetetramine or
tetraethylenepentamine with a fatty acid such as lauric is acid,
myristic acid, palmitic acid or stearic acid may be used. Further,
as the quaternary ammonium salt, an alkyltrimethylammonium salt
such as lauryltrimethylammonium chloride or the like may be used.
Further, the sizing agent of the present invention may contain an
antistatic agent represented by an inorganic salt such as lithium
chloride or potassium chloride or a quaternary ammonium salt such
as an ammonium chloride type or an ammonium ethosulfate type.
[0040] The sizing agent to be used in the present invention is
easily obtained by mixing the unsaturated copolymer of maleic
anhydride with an unsaturated monomer, the polyurethane resin in
the form of an emulsion or a dispersion and the silane coupling
agent in e.g. an aqueous medium, and preferably by mixing the
mixture with the polyacrylic acid or the copolymer of acrylic acid
with at least one monomer, and an assistant such as a fluorescent
brightening agent, a surfactant, a lubricant or an antistatic
agent.
[0041] In the present invention, in a case where the glass fiber
strands are treated with the above sizing agent having a specific
composition, it is required to apply the sizing agent to glass
fiber strands consisting of glass filaments immediately after spun
from a bushing. If it is attempted to apply the sizing agent to wet
chopped strands after being chopped, coating irregularity may occur
or the particle diameter of the product tends to be excessively
large, and some of the glass fibers are likely to remain
non-dispersed in the molded product. Accordingly, in the present
invention, it is preferred to carry out the treatment immediately
after spinning, i.e. preferably within 20 seconds, particularly
preferably within 5 seconds after the spinning.
[0042] The average fiber diameter of the glass filaments forming
the glass fiber strands to be treated with the sizing agent of the
present invention is preferably from 6 to 23 .mu.m, particularly
preferably from 10 to 16 .mu.m. Further, each glass fiber strand
preferably contains from 100 to 4,000, particularly preferably from
800 to 3,000 glass filaments, depending upon whether one glass
fiber strand is withdrawn to an impregnation die or a plurality of
strands are withdrawn. If the glass fiber diameter is less than 6
.mu.m, the impact strength of the molded product tends to decrease,
and if the glass fiber diameter exceeds 23 .mu.m, the stress at the
edge portions of the glass fibers in the molded product tends to be
high, and the molded product tends to have decreased tensile
strength and flexural strength.
[0043] The amount of the sizing agent to be used in the present
invention attached to the glass fiber strands is preferably from
0.1 to 2 mass % (glass fibers: 99.9 to 98.0 mass %), particularly
preferably from 0.2 to 0.8 mass %, as calculated as solid
content.
[0044] In the present invention, the glass fiber strands treated
with the sizing agent are wound on e.g. a tube as wet, and the
wound fiber strands are withdrawn and chopped preferably into from
1.5 to 13 mm. Otherwise, the glass fiber strands are chopped as
they are without being wound on a tube to obtain wet chopped
strands. Then, the wet chopped strands are dried. The drying
temperature and time are optional but drying is carried out
preferably at a temperature of from 120 to 180.degree. C.
preferably for from 10 seconds to 10 minutes so that superfluous
moisture will be removed.
[0045] The chopped strands thus produced are impregnated with a
molten thermoplastic resin to produce a fiber-reinforced molding
material. The thermoplastic resin may, for example, be a polyamide
resin such as nylon 6, nylon 66 or aromatic nylon, or two or more
types of polyamide resins, or a polymer alloy such as
polyamide-polyolefin or polyamide-polyphenylene ether.
[0046] In a case where a fiber-reinforced polyamide resin molding
material is produced by using a polyamide resin as the
thermoplastic resin, for example, the above chopped strands are
supplied to the polyamide resin molten in a screw extruder
preferably while being plasticized at from 260.degree. C. to
330.degree. C., and they are melt-kneaded. The melt-kneaded product
is molded into a fibrous reinforced polyamide resin body, which is
cut by e.g. a pelletizer to obtain a fiber-reinforced polyamide
molding material. In the present invention, to produce the
fiber-reinforced polyamide resin molding material, the above
temperature range is sufficient, but particularly preferred is from
280.degree. C. to 310.degree. C. for further improvement in the
dispersibility of the glass fibers in the final product.
[0047] The glass content in the thermoplastic resin molding
material of e.g. a polyamide resin is preferably from 5 to 70 mass
%, more preferably from 15 to 60 mass %. If the glass content of
the molding material exceeds 70 mass %, impregnation with the
thermoplastic resin tends to be insufficient, and the
dispersibility of the glass fibers tends to be poor at the time of
direct injection molding after mixing with the matrix resin. On the
other hand, if the glass content in the molding material is less
than 5 mass %, such a molding material is not practical considering
the glass content of current glass fiber-reinforced thermoplastic
resin products, and such is unfavorable in view of the cost.
EXAMPLES
[0048] Now, the present invention will be explained in further
detail with reference to Examples. However, it should be understood
that the present invention is by no means restricted to such
specific Examples.
Examples 1 to 8 and Comparative Examples 1 to 3
[0049] A sizing agent was prepared by mixing the following raw
material components in a composition as identified in Table 1.
(Raw-material Components for Sizing Agent)
[0050] Unsaturated copolymer A of maleic anhydride with butadiene
(number average molecular weight: 50,000)
[0051] Unsaturated copolymer B of maleic anhydride with butadiene
(number average molecular weight: 2,000)
[0052] Unsaturated copolymer C of maleic anhydride with butadiene
(number average molecular weight: 150,000)
[0053] Polyurethane resin A (PPG-IPDI): [0054] polyol component
(polypropylene glycol), isocyanate component (isophorone
diisocyanate)
[0055] Polyurethane resin B (PBA-IPDI): [0056] polyol component
(polybutylene adipate), isocyanate component (isophorone
diisocyanate)
[0057] polyurethane resin C (PPG-TDI): [0058] polyol component
(polypropylene glycol), isocyanate component (tolylene
diisocyanate)
[0059] silane coupling agent A:
.gamma.-aminopropyltriethoxysilane
[0060] silane coupling agent B:
N-.beta.-(aminoethyl)-.gamma.-aminopropyltrimethoxysilane
[0061] copolymer of acrylic acid with at least one monomer:
copolymer of acrylic acid with methylacrylate (number average
molecular weight: 10,000)
[0062] fluorescent brightening agent: benzoxazole fluorescent
brightening agent
[0063] Using the above prepared sizing agent, glass fiber strands
consisting of glass filaments were subjected to a surface treatment
within 1 second after spun from a bushing and then chopped to
produce chopped strands. Each chopped strand comprised 3,000 glass
filaments having an average diameter of 10 .mu.m bundled, had an
amount of the sizing agent attached of 0.45 mass % and had a length
of 3 mm.
[0064] Using the chopped strands and using polyamide 66 (injection
molding grade) as the matrix resin, they were kneaded and extruded
by means of a twin screw extruder (screw diameter: 35 mm,
285.degree. C.), and the extruded product was cut to produce
molding material pellets (cylindrical pellets having a diameter of
3 mm and a length of 3 mm, glass fiber content: 30 mass %).
[0065] Using the molding material pellets, injection molding was
carried out under a clamping pressure of 75 tons at a cylinder
temperature of 300.degree. C. at a mold temperature of 80.degree.
C. to obtain a molded product (a cup having a height of 100 mm, a
diameter of 100 mm and a thickness of 1 mm). With respect to the
molded product, the mechanical strength, the color tone, the
dispersibility of the glass fibers in the pellets, the
releasability at the time of injection molding, etc. were
evaluated.
[0066] Physical properties of the molded products obtained in
Examples and Comparative Examples are shown in Table 1. In Table 1,
TS, FS, IZOD and other performances were measured as follows.
[0067] Tensile strength (MPa): ASTM D-638 [0068] Flexural strength
(MPa): ASTM D-790 [0069] Notched IZOD impact strength (MPa): ASTM
D-256 (1/8 inch notch) [0070] Tensile strength after treatment
(MPa): Tensile strength after immersed in long life coolant
(LLC)/water=50/50 in volume ratio at 130.degree. C. for 500 hours.
[0071] Color tone evaluation: The color tone of the pellets was
measured by means of .SIGMA.-90 manufactured by NIPPON DENSHOKU
INDUSTRIES CO., LTD., and one having an "L" value of at least 72,
an "a" value of at most 2 and a "b" value of at most 15 was rated
very excellent. [0072] Glass fiber dispersibility (fibers/5 g
pellets): Carbon black was added to polyamide 66, and pellets were
molded with the screws that have very loosely kneading condition,
and 5 g of the obtained pellets were pressed at 300.degree. C. to
prepare a sheet having a thickness of 0.5 mm. The number of
non-dispersed glass fibers was visually measured. The smaller the
number, the better, and one containing non-dispersed glass fibers
of at most 50 fibers/5 g pellets was rated very excellent.
Releasability (kgf/cm.sup.2):
[0073] The force (mold release force) applied to the ejector pin
when the molded product was taken out from the mold, was measured.
The smaller the mold release force, the better, and one with a
force of at most 30 kgf/cm.sup.2 was rated very excellent.
[0074] As shown in Table 1, Examples were not inferior to
Comparative Examples in all characteristics of the color tone of
the molded product, the dispersibility of the glass in the pellets,
the releasability at the time of molding and the tensile strength
after immersion in hot water. Comparative Example 1 was inferior to
Example 1 in the color tone, the dispersibility of the glass in the
pellets and the releasability at the time of molding. Further,
Comparative Examples 2 and 3 wherein the proportions of the
copolymer of maleic anhydride with butadiene and the polyurethane
were out of the ranges of the present invention; were inferior in
the tensile strength after immersion in hot water. Further,
Examples 2 to 4 wherein the acrylic acid-methyl acrylate copolymer
was used, were superior to Example 1 in the color tone of the
molded product, the dispersibility of the glass in the pellets and
the releasability at the time of molding.
[0075] Further, Examples 1 to 4 wherein the copolymer of maleic
anhydride with butadiene having a preferred molecular weight of the
present invention was used, were superior to Example 5 in the
tensile strength after immersion in hot water, and were superior to
Example 6 in the dispersibility of the glass in the pellets.
Further, Examples 1 to 4 wherein the preferred polyurethane of the
present invention was used, were superior to Example 7 in the
tensile strength after immersion in hot water, and were superior to
Example 8 in the color tone of the molded product. TABLE-US-00001
EXAMPLE 1 Ex. Ex. Ex. Ex. 1 2 3 4 Coupling agent (diaminosilane)
0.5 0.5 0.5 Coupling agent (monoaminosilane) 0.5 Maleic
anhydride-butadiene copolymer A 2.3 2.3 2.3 2.0 B C Polyurethane
resin A 0.5 1.0 1.0 1.3 Polyurethane resin B Polyurethane resin C
Acrylic acid-methyl acrylate 0.3 0.3 0.4 copolymer Nonionic
surfactant 0.10 0.10 Oxazoline fluorescent brightening 0.01 agent
Solid content of sizing agent in 0.28 0.47 0.50 0.48 glass fibers
(%) Glass content (%) 29.6 29.8 29.8 29.9 Initial tensile strength
(MPa) 180 183 184 185 Tensile strength after treatment 43 44 43 45
(MPa) Flexural strength (MPa) 280 282 285 294 Izod impact strength
(KJ/m.sup.2) 11.5 11.6 11.7 11.7 Color tone (pellets) L value 72.9
73.6 73.5 75.8 a value -2.6 -2.2 -1.9 -2.5 b value 16.5 14.8 12.1
13.0 Dispersibility of glass fibers 52 38 36 20 (fibers) Mold
release force (kgf/cm.sup.2) 35 21 22 15 Ex. Ex. Ex. Ex. 5 6 7 8
Coupling agent (diaminosilane) 0.5 0.5 0.5 0.5 Coupling agent
(monoaminosilane) Maleic anhydride-butadiene copolymer A 2.3 2.3 B
2.3 C 2.3 Polyurethane resin A 0.5 0.5 Polyurethane resin B 0.5
Polyurethane resin C 0.5 Acrylic acid-methyl acrylate copolymer
Nonionic surfactant Oxazoline fluorescent brightening agent Solid
content of sizing agent in 0.24 0.35 0.28 0.28 glass fibers (%)
Glass content (%) 29.5 29.9 29.7 29.4 Initial tensile strength
(MPa) 178 182 182 180 Tensile strength after treatment 40 45 41 44
(MPa) Flexural strength (MPa) 276 288 278 281 Izod impact strength
(KJ/m.sup.2) 11.5 11.6 11.5 11.6 Color tone (pellets) L value 72.9
72.9 72.9 70.4 a value -2.6 -2.6 -2.6 -2.5 b value 16.4 16.7 16.5
17.3 Dispersibility of glass fibers 48 67 49 55 (fibers) Mold
release force (kgf/cm.sup.2) 33 38 34 37 Comp. Comp. Comp. Ex. 1
Ex. 2 Ex. 3 Coupling agent (diaminosilane) 0.5 0.5 0.5 Coupling
agent (monoaminosilane) Maleic anhydride-butadiene copolymer A 2.3
1.4 0.4 B C Polyurethane resin A 1.4 1.3 Polyurethane resin B
Polyurethane resin C Acrylic acid-methyl acrylate 2.0 copolymer
Nonionic surfactant Oxazoline fluorescent brightening agent Solid
content of sizing agent 0.27 0.28 0.48 in glass fibers (%) Glass
content (%) 29.8 29.5 29.4 Initial tensile strength (MPa) 185 181
180 Tensile strength after 45 35 34 treatment (MPa) Flexural
strength (MPa) 290 284 276 Izod impact strength (KJ/m.sup.2) 11.6
11.4 11.1 Color tone (pellets) L value 68.7 75.3 75.4 a value -2.4
-2.4 -2.4 b value 16.8 12.9 12.7 Dispersibility of glass fibers 84
34 28 (fibers) Mold release force (kgf/cm.sup.2) 56 28 24
INDUSTRIAL APPLICABILITY
[0076] Chopped strands comprising glass filaments to be obtained by
the present invention and a molded product from a fiber-reinforced
polyamide resin molding material using the chopped strands are
excellent in heat resistance and has high mechanical strength and
are thereby suitably used for various applications such as
automobiles, appliances and general industrial materials.
[0077] The entire disclosure of Japanese Patent Application No.
2004-089995 filed on Mar. 25, 2004 including specification, claims
and summary is incorporated herein by reference in its
entirety.
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