The present invention concerns a reinforced polyarylene sulfide resin
composition and a molding product thereof. More particularly, the prevent invention
concerns a polyarylene sulfide resin composition producing a molding product with
good surface and excellent surface luster, as well as excellent in heat resistance
and moldability and also excellent in mechanical property and, specially, it relates
to materials suitable for parts of automobiles, electric or electronic equipments,
etc., which are required heat resistance, mechanical property and surface smoothness,
for example, lamp reflectors.
In recent years, thermoplastic resins having high heat resistance
and chemical resistance, as well as flame retardancy have been demanded for materials
used for electric or electronic equipment parts, materials for automobile equipment
parts and materials for chemical equipment parts. A polyarylene sulfide resin
typically represented by a polyphenylene sulfide (PPS) resin is one of such reasons
capable of satisfying the above-mentioned requirement and their demand has been
increased. However, since the resin is somewhat expensive and fragile when used
alone, it has been generally practiced to improve the mechanical property and
the like by blending a fibrous reinforcing agent such as glass fibers and carbon
fibers or other fillers.
However, blend of such general inorganic fillers, particularly, fibrous
reinforcing agents such as glass fibers and carbon fibers providing a remarkable
effect for improving the mechanical strength involves a significant drawback of
worsening the flowing property and extremely deteriorating the smoothness at the
surface of the molding products thereby making the surface luster poor. In view
of the above, it has been keenly demanded for reinforced resin compositions being
excellent in the effect of enhancing the moldability and the mechanical strength
of a polyarylene sulfide resin and capable of providing molding products having
excellent surface smoothness, surface luster and the like, but those capable of
satisfying the object can no yet been obtained.
In view of the foregoing problems, it is an object of the present
invention to provide a reinforced polyarylene sulfide resin material of excellent
moldability, having excellent mechanical property and heat resistance, as well
as providing smooth surface and excellent luster when it is prepared as a molding
The present inventors have made a study for solving the foregoing
problem and, as a result, have found that the poor surface state of an existent
molding products based on the fiber-reinforced composition comprising a polyarylene
sulfide resin as the main ingredient and using glass fibers or carbon fibers is
attributable to the fibrous material used as the reinforcing agent, and have made
an extension search and study on the fibrous material causing no such surface
roughening and having reinforcing effect and, as a result, have accomplished the
present invention based on the finding that specific mineral fibers or ceramic
fibers shown below are extremely effective.
That is, the present invention concerns a reinforced polyarylene
sulfide resin composition comprising (A) 100 parts by weight of a polyarylene
sulfide resin and (B) 1 to 200 parts by weight of mineral fibers and/or ceramic
fibers having a chemical composition comprising 35 to 50 wt% of SiO&sub2;, 8 to
20 wt% of Al&sub2;O&sub3;, 10 to 50 wt% of CaO and 3 to 20 wt% of MgO, represented
as oxide and a molding product with good surface state prepared by molding the
The polyarylene sulfide resin as the ingredient (A) in the composition
according to the present invention mainly comprises repeating unit -(-Ar-S-)-(in
which Ar is arylene group). As the arylene group (-Ar-) there can be used, for
example, p-phenylene group, m-phenylene group, o-phenylene group, substituted
phenylene group (in which the substituent is an alkyl group, preferably C&sub1;
- C&sub5; alkyl group or a phenylene group), p,p&min;-diphenylene sulfone group,
p,p&min;-biphenylene group, p,p&min;-diphenylene ether group, p,p&min;-diphenylene
carbonyl group and naphthalene group.
In this case, among arylene sulfide groups constituted with the arylene
groups as described above, a polymer using identical repeating units, that is,
a homopolymer may be used. Further, in view of the processability for the composition,
a copolymer containing different kinds of repeating units may be preferred depending
on the case.
As the homopolymer, a substantially linear homopolymer containing,
as the repeating unit, p-phenylene sulfide groups using the p-phenylene group
as the arylene group is used particularly preferably.
As the copolymer, a combination of two or more of different kinds
of the arylene sulfide groups comprising the arylene group as described above can
be used, in particular, a combination mainly composed of p-phenylene sulfide group
and containing m-phenylene sulfide group, is used particularly preferably. Among
them, a substantially linear copolymer containing more than 60 mol%, preferably,
more than 70 mol% of p-phenylene sulfide groups is appropriate in view of the
physical property such as heat resistance, moldability and mechanical property.
In this case, a copolymer containing the repeating units of the component not
at random but in a block-forms (for example, as described in Japanese Patent Laid-Open
14228/1986) has good processability and excellent heat resistance and mechanical
property and can be used preferably.
For the polyarylene sulfide resin as the ingredient (A) used in the
present invention, a polymer obtained from a relatively low molecular weight linear
polymer by increasing the melt viscosity under oxidizing crosslinking or thermal
crosslinking thereby improving the moldability can be used, but a substantially
linear high molecular weight polymer obtained from difunctional monomers by polycondensation
can also be used. In most cases, the latter substantially linear polymer has higher
physical property for the resultant molding product and is preferred.
Further, as the polyarylene sulfide resin according to the present
invention, it is also possible and suitable to use a crosslinked polyarylene sulfide
resin polymerized by using, in admixture, those monomers having three or more functional
groups as the portion of the monomer, or a blend resin prepared by blending the
same with the linear polymer described above, in addition to the polymer described
Then, the reinforcing agent used as the ingredient (B) in the present
invention is mineral fibers and/or ceramic fiber having specified chemical composition,
comprising, as oxides, 35 to 50 wt% of SiO&sub2;, 8 to 20 wt% of Al&sub2;O&sub3;,
10 to 40 wt% of CaO and 3 to 20 wt% of MgO and, further, it may contain less than
10 wt% of FeO or the ingredient such as TiO&sub2;, MnO, Na&sub2;O and K&sub2;O
each by less than 3 wt%. In accordance with the present invention, a molding product
capable of sufficiently providing a reinforcing effect to the mechanical property
of a molding product as the object of the present invention and, in addition, remarkably
improved at the surface state of the molding product as compared with that of
a molding product comprising fibrous reinforcing agent such as glass fibers and
carbon fibers used generally, by blending the mineral fibers and/or ceramic fibers
comprising the chemical composition described above.
If the content of the ingredients as the reinforcing agent are out
of the range as defined in the present invention, it is not preferred since at
least one of the mechanical property and the surface state of the molding product
is worsened. For instance, if the SiO&sub2; content exceeds 50% by weight, the
property approaches to that of usual glass fibers to worsen the surface state when
it is prepared into a molding product. On the other hand, if it is less than 35%
by weight, it tends to reduce the reinforcing effect for the mechanical property.
Further, also for Al&sub2;O&sub3;, CaO and MgO, if the content is excessive or
insufficient, the effect for reinforcing the mechanical property is reduced, or
the effect to the surface state of the molding product is not sufficient, and
the handlability, moldability, heat resistance and the like upon preparation may
not be preferred depending on the case.
Further, in the present invention, the mineral fibers or ceramic
fibers as the ingredient (B) preferably have an average fiber diameter within a
range of 2 to 10 µm and an average fiber length within a range of 50 to 800 µm
and, particularly, an average diameter of 4 to 8 µm and an average fiber length
of 150 to 800 µm. Those with smaller fiber diameter are difficult to be prepared,
whereas those of excessively large diameter reduce the effect for reinforcing the
mechanical property. Further, if the fiber length is insufficient, the reinforcing
effect is also reduced. On the other hand, if it is excessive, it hinders the
flowing property of the composition and it is not preferred in view of the moldability.
In addition, the surface state of the molding product is neither sufficient.
The fibrous reinforcing agent used as the ingredient (B) in the present
invention is prepared as fibers containing the above-mentioned chemical ingredients
by melting and purifying specific natural rocks, for example, igneous rocks such
as basalt, or blast furnace slags by-produced upon iron making, spinning and then
forming them into fibers of a desired diameter. Then, they are chopped or cut by
an appropriate chopper or cutter and may be used as they are while partially containing
powdery material. If required, it may be classified after cutting to selectively
use those with an appropriate fiber length. The mineral fibers or ceramic fibers
as such ingredient (B) can be available from marketed products, for example, "LAPINUS
ROCKFIL" trade name of products manufactured by ROCKWOOL LAPINUS B. V., or "S-FIBERS-FF"
trade name of products manufactured by Shin Nippon Seitetsu Co. Ltd..
The reinforcing agent as the ingredient (B) used in the present invention
may be used as it is, but it may be used after being applied a surface treatment
or gathering treatment by using a known surface treating agent, for example, an
organosilane compound, an organoborane compound, an epoxy compound or an organotitanate
compound and a coupling agent such as an isocyanate compound. The surface treating
agents may be added simultaneously with the preparation of the composition. In
particular, surface treatment with, or addition of an amino alkoxy silane, epoxy
alkoxy silane, vinyl alkoxy silane or mercapto alkoxy silane is effective to the
Further, for the reinforcing agent of the ingredient (B), those prepared
by gathering using other appropriate organic materials for preventing fluffing
and scattering upon preparation of the composition may also be used.
In the present invention, the content for the ingredient (B) is from
1 to 200 parts by weight, preferably 5 to 150 parts by weight based on 100 parts
by weight of the polyarylene sulfide resin. If the blending amount of the ingredient
(B) is insufficient, the effect for reinforcing the mechanical property is not
sufficient. On the other hand, if it is excessive, the moldability is worsened
and the surface state of the molding product is also worsened thereby making it
difficult to attain the object of the present invention. Further, in the composition
according to the present invention, use of a fibrous reinforcing agent other than
the ingredient (B) is not hindered so long as this does not particularly hinder
the object of the present invention and, for instance, it is possible to use a
small amount of an organic polymer fibers having high melting point such as fluoro
resin fibers, aromatic polyamide fibers and potassium titanate fibers together.
However, since the combined use of the glass fibers or carbon fibers used generally
as the reinforcing agent for the polyarylene sulfide resin has an effect of remarkably
worsening the surface state of the molding product as described above and results
in a trouble to attain the object of the present invention, it is desirable not
to use them in combination and, if they are used in combination, it should be
restricted to an extremely small content, for instance, to less than 1/5 of the
mineral fibers or ceramic fibers as the ingredient (B).
Then, in the composition according to the present invention, a powdered
and granulated filler (including hollow) or a plate-like filler can be blended
further as the ingredient (C) together with the ingredient (B), although it is
not essential. Such filler (C) is preferably used together with the ingredient
(B) in view of eliminating the anisotropy in the shrinkage and suppressing warping
deformation upon molding to improve the dimensional accuracy or improving the
electric property and heat resistance. Anyone among powdery, granular, spherical,
hollow and plate-like shapes may be used together with the ingredient (B), possibly
two or more kinds of them may be used, depending on the purpose.
The combined use of the filler (C) does not hinder the surface state
so much as the molding product and it is effective for making a good balance among
the physical properties as described above in the aimed molding product.
Referring to the examples of the ingredient (C), there can be mentioned
as the powdery and granular filler, for example, silicates such as molten silica,
quartz powder, glass beds, glass powder, calcium silicate, aluminum silicate,
kaolinite, talc, clay, diatomaceous earth and wollastonite, metal oxides such
as iron oxide, titanium oxide and alumina, metal carbonates such as calcium carbonate
and magnesium carbonate, metal sulfates such as calsium sulfate and barium sulfate,
as well as silicone carbide, silicon nitride, boron nitride and a powdery and granular
particle of SiO&sub2;-Al&sub2;O&sub3; compound identical with or different from
the ingredient (B).
As the plate-like filler, there can be mentioned, for example, mica,
glass flake and talc. Further, as the hollow filler, there can be mentioned, for
example, siras balloon, metal balloon, glass balloon, SiO&sub2;-Al&sub2;O&sub3;
series hollow particles.
The average particle size of the filler (C) is less than 20 µm, preferably
less than 10 µm for the general powdery and granular particles, less than 50 µm,
preferably less than 40 µm for the spherical or flat-type material. If the above-mentioned
limit of the filler (C) is exceeded, the surface state of the molding product
tends to be worsened, depending on the shape of the filler, and it is not preferred
in view of the surface state of the molding product aimed at in the present invention.
Further, the blending amount of the filler (C) is less than 150 parts
by weight, preferably less than 130 parts by weight based on 100 parts by weight
of the polyarylene sulfide resin. Further, the sum with the ingredient (B) is
less than 250 parts by weight, preferably less than 200 parts by weight based on
100 parts by weight of the polyarylene sulfide. If the ingredient (C) or the sum
of the ingredient (B) and the ingredient (C) is excessive, it results in a problem
in the moldability and is not preferred also in view of the surface state of the
molding product. The filler (C) may also be used as it is, but it may, alternatively,
be used after being applied a surface treatment by a coupling agent or being gathered
by other organic compound in the same manner as for the ingredient (B).
In the composition according to the present invention, other thermoplastic
resins can be blended additionally in a small amount within a range not departing
from the object of the invention and they include, for example, vinyl resins such
as polyvinyl chloride resin and polyvinylidene chloride resin, polycarbonate resin,
polyamide resin, polyimide resin, polyolefin resin, polyester resin, polyether
resin, polysulfone resin, epoxy resin, natural rubber and synthetic rubber. Further,
additives such as flame retardant, antioxidant, UV-ray inhibitor, lubricant, releasing
agent, nucleating agent, foaming agent, cross-linker and colorant may be added
The composition according to the present invention can be prepared
by various known preparation methods by melting and kneading. For instance, it
is a general procedure to previously mix required ingredients uniformly by a mixer
such as a tumbler and Henschel mixer, supply the mixture to a one-shaft or two-shaft
extruder and pelletize by melt kneading and then serve the same to molding. Upon
pelletization, the ingredient (B) and, if required, the ingredient (C) may be
added to the ingredient (A) once melted in the extruder, and this method is effective
for preventing the flexing of the fibrous material. Further, it is possible to
mix the required ingredients, directly supply the mixture to a molding machine
and mold them as they are after melt kneading.
As shown in the foregoing descriptions, since the composition according
to the present invention has excellent moldability, heat resistance and mechanical
property, has an extremely improved surface state such as smoothness and luster,
particularly, in a case when it is prepared into a molding product, as compared
with compositions blended with known glass fibers or known carbon fibers as the
fibrous reinforcing agent for a polyarylene sulfide resin, it can be used suitably
to various kinds of materials for equipments requiring such satisfactory appearance
and properties, for example, parts of equipments aiming for optical reflection,
Further, such surface state is also effective for attaining a smooth
surface state in a case of coating a thin film on the surface of molding products
such as coating, sputtering, plating, vaccum evaporation coating and ion plating.
The present invention will now be described more specifically referring
to examples, but the invention is not restricted only to them.
(Examples 1 - 12, Comparative Examples 1 - 9)
Pellets of a polyolefin sulfide resin composition were prepared by
adding a reinforcing agent (B) of the present invention and (B&min;) for comparison
whose chemical compositions are as shown in Table 1 and, if necessary, a powdery
and granular filler or a pellet-like filler (C) to a polyphenylene sulfide resin
(PPS) (The formulations are Tables 2 and 3), well mixing them in a blender, melt
kneading the mixture in an extruder at a cylinder temperature of 310°C. Then,
test pieces were molded by an injection molding machine at a cylinder temperature
of 320°C and a die temperature of 150°C and physical values (tensile strength
and elongation, bending property) thereof were measured.
Further, for measuring the smoothness at the surface of the molding
products, a flat plate of 120 mm x 120 mm x 3 mm was molded by using an injection
molding machine at a cylinder temperature of 320°C and a die temperature of 150°C,
and a clearness of reflection light thereof was measured by using a image reflecting
measuring device (manufactured by Suga Shikenki). That is, light was entered at
an angle of 45° to a specimen molding plate, reflection light at 45° was allowed
to pass through an optical comb of 1.0 mm width, the maximum value M in the bright
portion and the minimum value m in the dark portion for the transmission light
passed through the optical comb were measured by a light receiving device, to
determine the image clearness (%) in accordance with the following equation.
Light source: tungsten filament,
Light wavelength: 400 to 700 nm
Image clearness (%) = M - m / (M + m)x 100
A greater value shows that the clearness is high and the specimen
plate is smooth. On the other hand, if the value is small, it shows that "blur"
or "distortion" is caused and the surface of the specimen plate is coarse.
The results are shown in Tables 2 and 3.
A reinforced polyarylene sulfide composition characterised by comprising:
(A) a polyarylene sulfide resin, and for every 100 parts by weight thereof
(B) from 1 to 200 parts by weight of mineral fibers and/or ceramic fibers having
a chemical composition comprising 35 to 50 wt% of SiO&sub2;, 8 to 20 wt% of Al&sub2;O&sub3;,
10 to 40 wt% of CaO and 3 to 20 wt% of MgO, represented as oxide.
A reinforced polyarylene sulfide resin composition as claimed in claim 1, characterised
in that the mineral fibers and/or ceramic fibers as the ingredient (B) have an
average diameter of 2 to 10µm and an average fiber length of 50 to 800 µm.
A reinforced polyarylene sulfide resin composition as claimed in claim 1 or
2, characterised in that the resin composition further comprises (C) 1 to 150
parts by weight of a powdered and granulated filler and/or a plate-like filler
based on 100 parts by weight of the polyarylene sulfide resin as the ingredient
A molding product with good surface state prepared by molding the reinforced
polyarylene sulfide resin composition as claimed in any of claims 1 to 3.