U.S. patent application number 09/777878 was filed with the patent office on 2002-05-09 for flame retardant thermoplastic resin composition.
Invention is credited to Matsusaka, Kunio, Noro, Masahiko, Sumimoto, Norifumi.
Application Number | 20020055565 09/777878 |
Document ID | / |
Family ID | 18412226 |
Filed Date | 2002-05-09 |
United States Patent
Application |
20020055565 |
Kind Code |
A1 |
Sumimoto, Norifumi ; et
al. |
May 9, 2002 |
Flame retardant thermoplastic resin composition
Abstract
The present invention relates to a flame retardant thermoplastic
resin composition comprising: (A) 100 parts by weight of a
rubber-reinforced thermoplastic resin comprising: a graft copolymer
(A1) produced by graft-polymerizing a monomer component (b)
containing an aromatic vinyl compound, a cyanided vinyl compound
and, if required, the other copolymerizable monomer in the presence
of a rubber polymer (a) containing polymer particles having a
particle size of not more than 150 nm in an amount of 0 to 15% by
weight, polymer particles having a particle size of from more than
150 to less than 350 nm in an amount of 60 to 100% by weight and
polymer particles having a particle size of not less than 350 nm in
an amount of 0 to 40% by weight, or a mixture of the graft
copolymer (A1) and a copolymer (A2) of monomer component (b'), said
rubber-reinforced thermoplastic resin (A) having a graft ratio of
20 to 150% and a rubber polymer content of 8 to 20% by weight; and
(B) 5 to 20 parts by weight of a phosphorus-based flame retardant
comprising a condensed phosphoric acid ester, a phosphazene
compound or mixture thereof.
Inventors: |
Sumimoto, Norifumi; (Tokyo,
JP) ; Noro, Masahiko; (Tokyo, JP) ; Matsusaka,
Kunio; (Tokyo, JP) |
Correspondence
Address: |
NIXON & VANDERHYE P.C.
8th Floor
1100 North Glebe Road
Arlington
VA
22201-4714
US
|
Family ID: |
18412226 |
Appl. No.: |
09/777878 |
Filed: |
February 7, 2001 |
Current U.S.
Class: |
524/127 ;
524/239 |
Current CPC
Class: |
C08K 5/49 20130101; C08L
55/00 20130101; C08L 55/02 20130101; C08L 55/00 20130101; C08L
51/04 20130101; C08L 51/04 20130101; C08L 51/04 20130101; C08L
55/02 20130101; C08L 55/02 20130101; C08F 279/04 20130101; C08F
279/02 20130101; C08L 51/04 20130101; C08L 55/02 20130101; C08L
2666/02 20130101; C08L 55/00 20130101; C08K 5/49 20130101; C08L
2666/02 20130101; C08L 2666/14 20130101; C08L 2666/24 20130101;
C08L 2666/24 20130101; C08L 2666/04 20130101; C08L 2666/04
20130101 |
Class at
Publication: |
524/127 ;
524/239 |
International
Class: |
C08K 005/52 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 9, 1999 |
JP |
11-350695 |
Claims
What is claimed is:
1. A flame retardant thermoplastic resin composition comprising:
(A) 100 parts by weight of a rubber-reinforced thermoplastic resin
comprising: a graft copolymer (A1) produced by graft-polymerizing a
monomer component (b) containing an aromatic vinyl compound, a
cyanided vinyl compound and, if required, the other copolymerizable
monomer in the presence of a rubber polymer (a) containing polymer
particles having a particle size of not more than 150 nm in an
amount of 0 to 15% by weight, polymer particles having a particle
size of from more than 150 to less than 350 nm in an amount of 60
to 100% by weight and polymer particles having a particle size of
not less than 350 nm in an amount of 0 to 40% by weight, or a
mixture of the graft copolymer (A1) and a copolymer (A2) of monomer
component (b'), said rubber-reinforced thermoplastic resin (A)
having a graft ratio of 20 to 150% and a rubber polymer content of
8 to 20% by weight; and (B) 5 to 20 parts by weight of a
phosphorus-based flame retardant comprising a condensed phosphoric
acid ester, a phosphazene compound or mixture thereof, which
condensed phosphoric acid ester is represented by the general
formula (I): 5wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are
independently phenyl or xylenyl; X is a divalent group derived from
resorcinol or bisphenol A; and n is 0.5 to 1.2.
2. A flame retardant thermoplastic resin composition according to
claim 1, further comprising 0.5 to 10 parts by weight of a
lubricant (C) based on 100 parts by weight of the component
(A).
3. A flame retardant thermoplastic resin composition according to
claim 2, wherein said lubricant (C) is ethylene bis-stearylamide,
methylene bis-stearylamide or a mixture thereof.
4. A flame retardant thermoplastic resin composition according to
claim 1, wherein said composition has a melt flow rate of 30 to 80
g/10 minutes when measured at 220.degree. C. under a load of 98N
according to JIS K7210.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a flame retardant
thermoplastic resin composition. More particularly, it relates to a
non-halogen-based flame retardant thermoplastic resin composition
which are excellent in impact resistance, heat resistance and flame
retardancy, especially practical impact resistance.
[0002] Conventionally, ABS resins having flame retardant properties
have been extensively used in various applications such as electric
and electronic devices and office automation (OA) devices because
these resins are excellent in moldability, mechanical properties or
the like. In recent years, there is a tendency that the use of
halogen-based flame retardants in these products should be avoided
from the viewpoint of environmental protection. For this reason,
there have been presently marketed such flame retardant materials
composed of a polycarbonate (PC)/ABS alloy resin as a base resin
and a phosphate-based flame retardant.
[0003] However, in the case where the polycarbonate (PC)/ABS alloy
resin is used in combination with the phosphate-based flame
retardant, the obtained materials tend to show a poor moldability
and be deteriorated in chemical resistance.
[0004] In consequence, conventionally, many studies have been made
to produce flame retardant materials from ABS base resins and a
non-halogen-based flame retardant without using the PC resins.
However, there have not been developed any practical materials
capable of exhibiting a flammability evaluation rating of V-0 or
higher as prescribed in UL94 as well as satisfactory
properties.
[0005] As a result of the present inventors' earnest study to solve
the above problem, it has been found that the problem can be solved
by such a flame retardant thermoplastic resin composition
comprising a specific rubber-reinforced thermoplastic resin and a
specific phosphorus-based flame retardant. The present invention
has been attained on the basis of the above finding.
SUMMARY OF THE INVENTION
[0006] An object of the present invention is to provide a flame
retardant thermoplastic resin composition containing an ABS resin
as a base resin and a phosphoric acid-based flame retardant which
is capable of exhibiting a flammability rating of V-2 as prescribed
in UL94 and can be used in extensive applications due to excellent
properties thereof.
[0007] To attain the above aim, in an aspect of the present
invention, there is provided a flame retardant thermoplastic resin
composition comprising:
[0008] (A) 100 parts by weight of a rubber-reinforced thermoplastic
resin comprising:
[0009] a graft copolymer (A1) produced by graft-polymerizing a
monomer component (b) containing an aromatic vinyl compound, a
cyanided vinyl compound and, if required, the other copolymerizable
monomer in the presence of a rubber polymer (a) containing polymer
particles having a particle size of not more than 150 nm in an
amount of 0 to 15% by weight, polymer particles having a particle
size of from more than 150 to less than 350 nm in an amount of 60
to 100% by weight and polymer particles having a particle size of
not less than 350 nm in an amount of 0 to 40% by weight, or a
mixture of the graft copolymer (A1) and a copolymer (A2) of monomer
component (b'),
[0010] said rubber-reinforced thermoplastic resin (A) having a
graft ratio of 20 to 150% and a rubber polymer content of 8 to 20%
by weight; and
[0011] (B) 5 to 20 parts by weight of a phosphorus-based flame
retardant comprising a condensed phosphoric acid ester, a
phosphazene compound or mixture thereof, which condensed phosphoric
acid ester is represented by the general formula (I): 1
[0012] wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are
independently phenyl or xylenyl; X is a divalent group derived from
resorcinol or bisphenol A; and n is 0.5 to 1.2.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The rubber-reinforced thermoplastic resin (A) used in the
present invention (hereinafter referred to as "rubber-reinforced
resin") comprises a graft copolymer (A1) produced by
graft-polymerizing a monomer component (b) containing an aromatic
vinyl compound, a cyanided vinyl compound and, if required, the
other copolymerizable monomer in the presence of a rubber polymer
(a) having a specific particle size distribution, or a mixture of
the graft copolymer (A1) and a copolymer (A2) of a monomer
component (b').
[0014] As the rubber polymers (a), there may be exemplified
polybutadiene, hydrogenated products of polybutadiene,
styrene/butadiene copolymers, butadiene/acrylonitrile copolymers,
ethylene/propylene or ethylene/propylene/non-conjugated diene
copolymers, ethylene/butene-1 or ethylene/butene-1/non-conjugated
diene copolymers, isobutylene/isoprene copolymers, acrylic rubbers,
styrene/butadiene/styrene block copolymers,
styrene/isoprene/styrene block copolymers, polyurethane rubbers,
silicone rubbers or the like. Examples of the styrene/butadiene
copolymers may include styrene/butadiene random copolymers,
styrene/butadiene block copolymers or hydrogenated products
thereof.
[0015] The rubber polymers may be used alone or in the form of a
mixture of any two or more thereof. Among these rubber polymers,
polybutadiene, styrene/butadiene copolymers, ethylene/propylene or
ethylene/propylene/non-conjugated diene copolymers and silicone
rubbers are preferred. The rubber polymers used in the present
invention are preferably latex-like polymers though not limited
thereto.
[0016] In the present invention, the particle size distribution of
the rubber polymer (a) is very important. The rubber polymer is
required to have the following particle size distribution. Namely,
the rubber polymer contains polymer particles having a particle
size of not more than 150 nm in an amount of 0 to 15% by weight,
preferably 0 to 12% by weight; polymer particles having a particle
size of from more than 150 to less than 350 nm in an amount of 60
to 100% by weight, preferably 65 to 100% by weight; and polymer
particles having a particle size of not less than 350 nm in an
amount of 0 to 40% by weight, preferably 0 to 35% by weight.
[0017] When the particle size distribution of the rubber polymer
which has a large influence on rubber orientation of molded
products, lies within the above-specified range, the obtained
molded products can exhibit a good practical impact strength. Here,
the "rubber orientation" means such a phenomenon that rubber
particles are deformed in the flowing direction by shear force
applied upon molding. When the rubber orientation becomes
remarkable, the practical impact strength of the obtained molded
product is lowered. When the content of the rubber polymer having a
particle size of not more than 150 nm is more than 15% by weight,
the stress distribution effect by rubber particles within the
molded product may be deteriorated, resulting in poor practical
impact strength of the molded product. When the content of the
rubber polymer having a particle size of not less than 350 nm is
more than 40% by weight, the rubber orientation of the molded
product becomes considerably increased, resulting in poor practical
impact strength of the molded product. Meanwhile, the "practical
impact strength" used in the present invention means a falling
weight impact strength.
[0018] The particle size distribution of the rubber polymer (a) may
be controlled by appropriately selecting kind and amount of
emulsifier, kind and amount of initiator, polymerization time,
polymerization temperature, stirring conditions, etc., which are
ordinarily used upon the production of the rubber polymer.
Alternatively, the particle size distribution of the rubber polymer
(a) may also be controlled by blending at least two kinds of rubber
polymers (a) having different particle sizes with each other.
[0019] The rubber polymer (a) has a gel fraction of preferably 40
to 98% by weight, more preferably 50 to 95% by weight, especially
preferably 60 to 90% by weight. When the gel fraction of the rubber
polymer (a) lies within the above specified range, the obtained
molded product is more excellent in gloss and impact resistance on
the surface thereof.
[0020] Meanwhile, the gel fraction of the rubber polymer (content
of toluene-insoluble components) is determined by the following
manner. One gram of the rubber polymer is added to 100 ml of
toluene. The resultant mixture is allowed to stand at room
temperature for 48 hours, and then filtered through a 100-mesh
metal screen. The thus separated filtrate is dried to remove
toluene therefrom, thereby determining a content (g) of
toluene-soluble components. From the thus measured content of
toluene-soluble components, the gel fraction of the rubber polymer
(a) is calculated according to the following formula:
Gel Fraction (%)=(1(g)-content of toluene-soluble components
(g)).times.100
[0021] The content of the rubber polymer (a) in the above
rubber-reinforced resin (A) is in the range of usually 8 to 20% by
weight, preferably 8 to 18% by weight, more preferably 10 to 15% by
weight. When the content of the rubber polymer used in the
component (A) is too small, the obtained composition may be
deteriorated in impact strength. On the other hand, when the
content of the rubber polymer used in the component (A) is too
large, the obtained composition may be deteriorated in not only
fluidity and stiffness, but also in flammability evaluation rating
(flame retardancy).
[0022] The gel fraction of the rubber polymer (a) can be controlled
by appropriately selecting kind and amount of chain transfer agent,
polymerization time, polymerization temperature, final
polymerization conversion rate, etc., upon the production of the
rubber polymer (a).
[0023] The monomer component (b) used in the component (A) contains
an aromatic vinyl compound, a cyanided vinyl compound and, if
required, the other copolymerizable monomer.
[0024] Examples of the aromatic vinyl compounds used in the
component (A) may include styrene, .alpha.-methyl styrene, o-methyl
styrene, p-methyl styrene, tert-butyl styrene, vinyl toluene,
methyl-.alpha.-methyl styrene, divinyl benzene or the like. Among
these aromatic vinyl compounds, styrene and .alpha.-methyl styrene
are especially preferred.
[0025] When .alpha.-methyl styrene is used as the monomer component
(b) in an amount of 10 to 50% by weight, preferably 20 to 30% by
weight, it is possible to impart a more excellent heat resistance
to the resin composition of the present invention.
[0026] The amount of the aromatic vinyl compound used in the
component (A) is preferably 40 to 92% by weight, more preferably 50
to 80% by weight, especially preferably 50 to 70% by weight based
on the weight of the monomer component (b). When the amount of the
aromatic vinyl compound used is too small, the obtained resin
composition may be deteriorated in fluidity and heat stability. On
the other hand, when the amount of the aromatic vinyl compound used
is too large, the obtained resin composition may be deteriorated in
stiffness and chemical resistance.
[0027] As the cyanided vinyl compounds used in the component (A),
there may be exemplified acrylonitrile, methacrylonitrile or the
like. Among these cyanided vinyl compounds, acrylonitrile is
preferred.
[0028] The amount of the cyanided vinyl compound used in the
component (A) is preferably 5 to 45% by weight, more preferably 5
to 40% by weight, especially preferably 10 to 45% by weight based
on the weight of the monomer component (b). When the amount of the
cyanided vinyl compound used is too small, the obtained resin
composition may be deteriorated in stiffness and chemical
resistance. On the other hand, when the amount of the cyanided
vinyl compound used is too large, the obtained resin composition
may be deteriorated in heat stability and fluidity.
[0029] Further, the component (A) may contain the other
copolymerizable monomer component, if required. As the other
copolymerizable monomer components, there may be exemplified
unsaturated acid anhydrides, unsaturated acids, imide compounds of
unsaturated dicarboxylic acids or the like.
[0030] Examples of the unsaturated acids may include maleic
anhydride, itaconic anhydride, citraconic anhydride or the like.
Examples of the unsaturated acids may include acrylic acid,
methacrylic acid or the like. Examples of the imide compounds of
unsaturated dicarboxylic acids may include maleimide, N-methyl
maleimide, N-butyl maleimide, N-phenyl maleimide,
N-(2-methylphenyl)maleimide, N-(4-hydroxyphenyl)maleimide,
N-cyclohexyl maleimide or the like.
[0031] The respective monomer components (b) contained in the
component (A) may be used alone or in the form of a mixture of any
two or more thereof.
[0032] Further, the component (A) may contain a functional
group-containing vinyl monomer as the other copolymerizable monomer
component.
[0033] Examples of the functional group-containing vinyl monomers
may include epoxy-containing unsaturated compounds such as glycidyl
acrylate, glycidyl methacrylate and aryl glycidyl ether;
hydroxy-containing unsaturated compounds such as
3-hydroxy-1-propene, 4-hydroxy-1-butene, cis-4-hydroxy-2-butene,
trans-4-hydroxy-2-butene, 3-hydroxy-2-methyl-1-pr- opene,
2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and
hydroxystyrene; unsaturated carboxylic acid amides such as
acrylamide and methacylamide; amino-containing unsaturated
compounds such as acrylamine, aminomethyl methacrylate, methacrylic
acid amino ether, aminopropyl methacrylate and aminostyrene;
unsaturated acids such as acrylic acid and methacrylic acid;
oxazoline group-containing unsaturated compounds such as vinyl
oxazoline; or the like. These functional group-containing vinyl
monomers may be used alone or in the form of a mixture of any two
or more thereof. When such a functional group-containing
unsaturated compound is copolymerized with the resin, the obtained
resin can exhibit a high interfacial adhesion property
(compatibility) to the other resin blended therewith.
[0034] The amount of the other copolymerizable monomer component
used is preferably 0 to 40% by weight, more preferably 0 to 30% by
weight, especially preferably 0 to 20% by weight based on the
weight of the monomer component (b).
[0035] The graft ratio of the monomer component (b) in the
rubber-reinforced resin (A) is in the range of 20 to 150%.
[0036] Here, the graft ratio (%) means a content of the monomer
component (b) grafted to the rubber polymer, and is expressed by
the value obtained according to the following formula:
Graft ratio (%)=100.times.(T-S)/S
[0037] wherein T represents the weight of insoluble component
obtained by adding 1 g of the rubber-reinforced resin to 20 ml of
acetone, shaking the mixture at room temperature for 2 hours using
a shaker and then centrifuging the mixture using a centrifugal
separator (rotating speed: 23,000 rpm) to separate the insoluble
component from a soluble component; and S represents the weight of
the rubber polymer contained in one gram of the rubber-reinforced
resin.
[0038] When the graft ratio is too small, the obtained molded
product may be deteriorated in impact strength. On the other hand,
when the graft ratio is too large, the obtained molded product may
be deteriorated in flame retardancy. Therefore, in order to improve
the flame retardancy and physical properties of the obtained molded
product, the graft ratio of the monomer component (b) in the
rubber-reinforced resin (A) is usually 20 to 150%, preferably 30 to
120%, more preferably 40 to 120%.
[0039] In the resin composition of the present invention, the
acetone-soluble component contained in the rubber-reinforced resin
(A) has an intrinsic viscosity [.mu.] of preferably 0.2 to 1.2
dl/g, more preferably 0.2 to 1 dl/g, especially preferably 0.3 to 1
dl/g when measured at 30.degree. C. in methyl ethyl ketone. When
the intrinsic viscosity lies within the above-specified range, it
is possible to obtain a resin composition having excellent impact
resistance, heat resistance and flame retardancy according to the
present invention.
[0040] Meanwhile, the above graft ratio (%) and intrinsic viscosity
[.eta.] can be readily controlled by varying kinds and amounts of
polymerization initiator, chain transfer agent, emulsifier,
solvent, etc., which are used upon the polymerization of the
rubber-reinforced resin.
[0041] Also, the acetone-soluble component contained in the
rubber-reinforced resin (A) has a ratio of Mw/Mn of preferably 2 to
4, more preferably 2 to 3 (wherein Mw represents a weight-average
molecular weight calculated as polystyrene, and Mn represents a
number-average molecular weight calculated as polystyrene), when
measured by gel permeation chromatography (GPC) using
tetrahydrofuran (THF). When the ratio of Mw/Mn lies in the
above-specified range, the obtained resin composition is
well-balanced between moldability and impact resistance.
[0042] The graft copolymer (A1) can be produced by subjecting the
monomer component (b) containing aromatic vinyl compound and
cyanided vinyl compound as main components to radical graft
polymerization by emulsion polymerization method or suspension
polymerization method in the presence of the rubber polymer (a). In
the emulsion polymerization method, there may be used
polymerization initiator, chain transfer agent, water or the
like.
[0043] Meanwhile, when the rubber polymer (a) and the monomer
component (b) are polymerized to produce the graft copolymer (A1),
the monomer component (b) may be added to the reaction system
either at a batch, in parts or continuously in the presence of the
rubber polymer (a). Also, the combination of the above addition
methods may be used for the polymerization. Further, a part or
whole of the rubber polymer (a) may be added in the course of the
polymerization.
[0044] Examples of the polymerization initiators may include
redox-type polymerization initiators containing an
organohydroperoxide such as typically cumene hydroperoxide,
diisopropylbenzene hydroperoxide and p-menthane hydroperoixde, and
a reducing agent such as typically sugar-containing pyrophosphoric
acid formulation and sulfoxylate formulation; persulfates such as
potassium persulfate; and peroxides such as benzoyl peroxide,
lauroyl peroxide, tert-butyl peroxylaurate and tert-butyl
peroxymonocarbonate. The polymerization initiator may be added
either at a batch or continuously to the polymerization system. The
amount of the polymerization initiator used is usually 0.1 to 1.5%
by weight, preferably 0.2 to 0.7% by weight based on the weight of
the monomer component (b).
[0045] Examples of the chain transfer agents may include mercaptans
such as octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl
mercaptan, n-hexyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl
mercaptan and tert-tetradecyl mercaptan; dimers of terpinolene or
.alpha.-methyl styrene; or the like. These chain transfer agents
may be used alone or in the form of a mixture of any two or more
thereof. The amount of the chain transfer agent used is usually
0.05 to 2% by weight based on the weight of the monomer component
(b).
[0046] As the emulsifiers used in the emulsion polymerization,
there may be exemplified sulfates of higher alcohols,
alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate,
aliphatic sulfonates such as sodium lauryl sulfate, higher
aliphatic carboxylates, anionic surfactants such as phosphoric
acid-based surfactants, and nonionic surfactants such as alkyl
ester-type or alkyl ether-type polyethylene glycols. These
emulsifiers may be used alone or in the form of a mixture of any
two or more thereof. The amount of the emulsifier used is usually
0.3 to 5.0% by weight based on the weight of the monomer component
(b).
[0047] Upon the production of the graft copolymer (A1) by emulsion
polymerization, the obtained graft copolymer may be usually
purified by coagulating the copolymer using a coagulant to form
particles thereof, washing the particles with water and then drying
the particles. As the coagulants, there may be used inorganic salts
such as calcium chloride, magnesium sulfate, magnesium chloride and
sodium chloride, and acids such as sulfuric acid and hydrochloric
acid.
[0048] Meanwhile, the rubber-reinforced resin (A) may be
constituted by the above graft copolymer (A1) solely or by a
mixture of the graft copolymer (A1) and the copolymer (A2) of a
monomer component (b'). Also, the monomer component (b') of the
copolymer (A2) may be the same as or different from that of the
monomer component (b) used for the production of the graft
copolymer (A1). Preferably, the monomer component (b') of the
copolymer (A2) may contain an aromatic vinyl compound and a
cyanided vinyl compound. In addition, the above copolymer (A2) may
be constituted by the combination (mixture) of two or more kinds of
copolymers (A2).
[0049] The above copolymer (A2) can be produced by subjecting the
monomer component (b') to emulsion polymerization, suspension
polymerization or the like in addition to the above-described graft
polymerization.
[0050] The acetone-soluble component contained in the above
copolymer (A2) has an intrinsic viscosity [.eta.] of preferably 0.2
to 1 dl/g, more preferably 0.3 to 1 dl/g, especially preferably 0.3
to 0.8 dl/g when measured at 30.degree. C. in methyl ethyl ketone.
When the intrinsic viscosity [.eta.] of the acetone-soluble
component lies in the above-specified range, it is possible to
obtain a flame retardant thermoplastic resin composition having
excellent impact resistance, heat resistance and flame retardancy
according to the present invention. The intrinsic viscosity [.eta.]
of the acetone-soluble component contained in the copolymer (A2)
can be controlled by the same method as used for that contained in
the above graft copolymer.
[0051] Typical examples of the rubber-reinforced resins (A) may
include combinations (mixtures) of the graft copolymer (A1) and the
copolymer (A2) as illustrated below, though not limited
thereto.
[0052] (1) Combination of acrylonitrile/butadiene/styrene resin and
acrylonitrile/styrene resin; and
[0053] (2) Combination of acrylonitrile/ethylene propylene/styrene
resin and acrylonitrile/styrene resin
[0054] The phosphorus-based flame retardant (B) may comprise a
condensed phosphoric acid ester represented by the general formula
(I): 2
[0055] and/or a phosphazene compound.
[0056] The condensed phosphoric acid esters represented by the
above general formula (I) may be used alone or in the form of a
mixture of any two or more different kinds thereof.
[0057] In the general formula (I), R.sup.1 to R.sup.4 individually
represent phenyl or xylenyl. The hydrogen atoms bonded to an
aromatic ring of the phenyl group may be substituted with alkyl or
the like. Also, X represents a group derived from a dihydroxy
compound such as resorcinol and bisphenol A. The condensed
phosphoric acid esters in themselves usable in the present
invention are known in the art.
[0058] In the present invention, when two or more condensed
phosphoric acid esters are used in the form of a mixture, "n" in
the general formula (I) represents an average value of "n"s of the
condensed phosphoric acid esters contained in the mixture. The
value of "n" is 0.5 to 1.2, preferably 0.7 to 1.2, more preferably
0.9 to 1.1. When the "n" is too small, the obtained resin
composition may be deteriorated in heat resistance, so that the
molded product produced therefrom tends to suffer from appearance
defects such as silver streaks. On the other hand, it may be
difficult to produce condensed phosphoric acid esters having a too
large value of "n".
[0059] As the phosphazene compounds used in the present invention,
there may be exemplified linear phosphazenes represented by the
following general formula (II) and/or cyclic phosphazenes represent
by the following general formula (III) as described, for example,
in "Studies in Inorganic Chemistry 6 Phosphorus (Third Edition)"
(ELSEVIER). 3
[0060] In the above general formulae (II) and (III), m is an
integer of 0 to 15, preferably 1 to 10; R is a functional group
selected from the group consisting of alkyl, allyl, alkoxy,
aryloxy, amino and hydroxy. The alkoxy and aryloxy groups may be
modified with alkyl, allyl, amino, hydroxy or the like. Also, the
amino group may be modified with alkyl, allyl or the like.
[0061] Examples of the phosphazene compounds used in the present
invention may include propoxyphosphazene, phenoxyphosphazene,
methylphenoxyphosphazene, aminophosphazene, fluoroalkylphosphazene
or the like. Among these phosphazene compounds, phenoxyphosphazene
is preferred in view of facilitated production thereof.
[0062] These phosphazene compounds may be used alone or in the form
of a mixture of any two or more thereof, for example, a mixture of
cyclic and linear phosphazenes. The substituents Rs contained in a
molecule of the phosphazene compound may be the same functional
group or different two or more kinds of functional groups. Specific
examples of the phosphazene compounds having different substituents
Rs may include those prepared by first substituting a part of
substitutable sites of the phosphazene molecule with phenoxy and
then substituting the remaining substitutable sites thereof with
propoxy, i.e., phenoxypropoxyphosphazenes.
[0063] The component (B) of the resin composition according to the
present invention may be composed of one or both of the condensed
phosphoric acid ester represented by the general formula (I) and
the phosphazene compound represented by the general formula (II) or
(III).
[0064] The amount of the component (B) blended is 5 to 20 parts by
weight, preferably 5 to 18 parts by weight, more preferably 5 to 15
parts by weight based on 100 parts by weight of the
rubber-reinforced resin (A). When the amount of the component (B)
blended is less than 5 parts by weight, the obtained resin
composition is insufficient in flame retardancy. On the other hand,
when the amount of the component (B) blended is too large, the
obtained resin composition is deteriorated in heat resistance.
[0065] The resin composition of the present invention may further
contain a lubricant (C). The lubricant (C) is preferably composed
of ethylene bis-stearylamide and/or methylene bis-stearylamide.
[0066] The amount of ethylene bis-stearylamide and/or methylene
bis-stearylamide blended is usually 0.5 to 10 parts by weight,
preferably 0.5 to 4 parts by weight, more preferably 0.5 to 3 parts
by weight, especially preferably 1 to 3 parts by weight based on
100 parts by weight of the rubber-reinforced resin (A). When the
amount of the lubricant blended lies in the above-specified range,
the obtained resin composition exhibit more excellent flame
retardancy and fluidity. When the amount of the lubricant blended
is too large, the obtained resin composition may be deteriorated in
flame retardancy.
[0067] The resin composition of the present invention comprises the
components (A) and (B) or the components (A) to (C), and has a melt
flow rate of preferably 30 to 80 g/10 minutes, more preferably 30
to 70 g/10 minutes, especially preferably 30 to 60 g/10 minutes
when measured at 220.degree. C. under a load of 98N according to
JIS K7210. When the melt flow rate is too small or too large, the
resin composition may be deteriorated in flame retardancy.
[0068] The melt flow rate of the resin composition according to the
present invention varies depending upon graft ratio, cyanided vinyl
compound content and rubber content of the component (A) as well as
amounts of the components (B) and (C) blended. The melt flow rate
may be usually controlled by varying the amount of the copolymer
(A2) blended.
[0069] Further, the content of organic acids and/or oligomers in
the resin composition of the present invention is preferably not
more than 4% by weight, more preferably not more than 2.5% by
weight, especially preferably not more than 2% by weight. When the
content of organic acids and/or oligomers lies in the
above-specified range, it is possible to avoid such a defective
phenomenon that an inner molding surface of the mold is
contaminated upon molding. The content of the organic acids can be
determined by dissolving the resin composition in a solvent
(1,4-dioxane), methyl-esterifying residual organic acids with
diazomethane and then measuring the obtained methyl ester using a
gas chromatograph equipped with hydrogen flame ionization
detector.
[0070] Also, the resin composition of the present invention has a
water content of preferably not more than 0.5% by weight, more
preferably 0.3% by weight, especially preferably 0.2% by weight.
When the water content lies in the above-specified range, the
obtained resin composition is more excellent in discoloration
resistance (color fastness). The water content is measured at
250.degree. C. by Karl Fisher's method.
[0071] The resin composition of the present invention may contain,
if required, fillers such as glass fibers, carbon fibers,
wollastonite, talc, mica, kaolin, glass beads, glass flakes, milled
fibers, zinc oxide whiskers and potassium titanate whiskers. These
fillers may be used alone or in the form of a mixture of any two or
more thereof. When these fillers are blended in the resin
composition of the present invention, it is possible to impart a
good stiffness thereto. Especially, when talc is blended in the
resin composition of the present invention, it is possible to
impart a good delustering property thereto. The glass fibers and
the carbon fibers have preferably a fiber diameter of 6 to 20 .mu.m
and a fiber length of not less than 30 .mu.m.
[0072] Further, the resin composition of the present invention may
also contain various additives such as flame retardants such as
antimony compounds, coupling agents, antibacterial agents,
mildew-proofing agents, antioxidants, weather (light) resisting
agents, plasticizers, colorants (such as pigments and dyes),
anti-static agents and silicone oils, unless the addition thereof
adversely affects the required performance of the resin
composition.
[0073] Further, the resin composition of the present invention may
be blended with the other polymers according to the required
performance thereof. As the other polymers blended, there may be
exemplified polycarbonates, polyethylene, polypropylene,
polyamides, polyesters, polysulfones, polyethersulfones,
polyphenylene sulfide, liquid crystal polymers, polyvinylidene
fluoride, styrene/vinyl acetate copolymer, polyamide elastomers,
polyamideimide elastomers, polyester elastomers, phenol resins,
epoxy resins, novolak resins or the like.
[0074] The resin composition of the present invention can be
obtained by kneading the respective components with each other
using various extruders, banbury mixer, kneader, rolls, feederuder
or the like. Among them, the use of extruders or banbury mixer is
preferred. Upon kneading, the respective components may be added at
a batch or in several parts. The kneading procedure may be
conducted using a multi-stage feed type extruder. Alternatively,
after the components are kneaded by banbury mixer, kneader or the
like, the kneaded material may be pelletized using an extruder.
[0075] The thus obtained resin composition of the present invention
may be shaped or molded into various products by injection molding,
sheet extrusion, vacuum forming, profile molding, foaming,
injection press, press molding, blow molding or the like.
[0076] Various molded products produced by the above molding
methods are excellent in impact resistance, heat resistance and
flame retardancy and, therefore, can be used in various
applications such as office automation devices, domestic electric
appliances, electric, electronic and telecommunication apparatuses,
computers, sundries, sanitary goods, vehicle parts or the like. In
particular, such products injection-molded using a pin-point gate
can be suitably used as housings for devices with built-in
electronic parts.
[0077] Thus, the resin composition of the present invention is a
non-halogen-based composition, and is excellent in impact
resistance, heat resistance and flame retardancy, especially
practical impact resistance.
EXAMPLES
[0078] The present invention will be described in more detail by
reference to the following examples. However, these examples are
only illustrative and not intended to limit the present invention
thereto.
[0079] Meanwhile, in Examples, Comparative Examples and Reference
Examples, "part" and "%" represents "part by weight" and "% by
weight", respectively, unless otherwise specified. Further, various
properties were evaluated by the following methods.
[0080] Particle Size and Particle Size Distribution of Rubber
Polymer:
[0081] The sizes of particles dispersed in latex were measured by
laser Doppler/frequency analysis. The measurement was conducted
using a granulometer ("MICRO-TRACK UPA150, MODEL NO. 9340"
manufactured by Nikkiso Co., Ltd.). Meanwhile, it was confirmed
that the size of the rubber polymer particles dispersed in the
rubber-reinforced resin were substantially identical to those
dispersed in latex.
[0082] Gel Fraction (Content of Toluene-insoluble Components):
[0083] The gel fraction was measured by the above method described
in the present specification.
[0084] Graft Ratio (Percentage):
[0085] The graft ratio was measured by the above method described
in the present specification.
[0086] Intrinsic Viscosity [.eta.]:
[0087] The rubber-reinforced resin was added into acetone. The
resultant mixture was shaken at room temperature for 2 hours using
a shaker, and then centrifuged for 60 minutes using a centrifugal
separator (rotating speed: 23,000 rpm), thereby separating the
mixture into acetone-insoluble components and acetone-soluble
components. The obtained acetone-soluble components were
sufficiently dried by a vacuum dryer. The dried acetone-soluble
components were dissolved in methyl ethyl ketone to prepare five
solutions having different concentrations. The reduced viscosities
of the five solutions was measured at 30.degree. C. by Ubbellode
viscometer. The intrinsic viscosities [.eta.] (unit: dl/g) was
calculated from the thus measured viscosities.
[0088] Fluidity (Melt Flow Rate):
[0089] The melt flow rate (unit: g/10 minutes) was measured at
220.degree. C. under a load of 98N according to JIS K7210.
[0090] Impact Resistance (Izod Impact Strength):
[0091] A test specimen No. 2 according to JIS K7110 was molded
using an injection molding machine J100E-C5 manufactured by Nippon
Seikosho Co., Ltd., by setting cylinder temperature and mold
temperature thereof to 220.degree. C. and 50.degree. C.,
respectively. The Izod impact strength (unit: J/m) of the test
specimen was measured according to ASTM D256.
[0092] Heat Deformation Temperature (HDT):
[0093] A test specimen having a size of 6.4 mm in width.times.128
mm in length.times.12.8 mm in thickness, was measured under a
bending stress of 18.5 kgf/cm.sup.2 according to JIS K7207.
[0094] Flammability Evaluation (Flame Retardancy):
[0095] A test specimen of 5" in length.times.{fraction (1/2)}" in
width.times.{fraction (1/12)}" in thickness was subjected to
vertical flame test by the method prescribed in UL94. In the
evaluation results, "V-2" represents V-2 acceptance in the vertical
flame test, and "B" represents "burning", i.e., V-2
non-acceptance.
[0096] Falling Weight Impact Strength:
[0097] The breaking energy of a test specimen having a size of 50
mm.times.80 mm.times.2.4 mm was measured using a high-speed impact
tester "SERVO-PULSER EHF-2H-20L" manufactured by Shimadzu
Seisakusho Co., Ltd. The measuring conditions were as follows:
Specimen pedestal diameter: 30 mm.phi.; Striking bar tip: 12.7 mmR;
Striking speed: 3.1 m/s. The unit of the falling weight impact
strength is "kgf.multidot.cm".
Reference Example 1
Preparation of Rubber Polymer
[0098] As rubber polymers (a-1) to (a-3), there were used
polybutadiene latexes shown in Table 1 below.
1 TABLE 1 Rubber polymer (a-1) (a-2) (a-3) Polybutadiene latex
Particle size distribution (%) not more than 150 nm 12 48 13 from
more than 150 nm 80 49 38 to less than 350 nm not less than 350 nm
8 3 49 Gel fraction (%) 78 82 69
Reference Example 2
Preparation of Component (A)
[0099] The rubber polymers (a-1) to (a-3) were respectively
emulsion-polymerized with styrene and acrylonitrile as the monomer
component (b) at mixing ratios shown in Table 2 thereby obtaining
graft copolymers (A1-1) and (A1-2), and (A'1-1) to (A'1-6) having
different graft ratios as shown in Table 2,. Separately, only
styrene and acrylonitrile as the monomer component (b) were
solution-polymerized with each other at mixing ratios shown in
Table 2, thereby obtaining copolymers (A2-1) to (A2-4). The
intrinsic viscosities [.eta.] of the thus obtained graft copolymers
(A1) and copolymers (A2) are shown in Table 2.
2 TABLE 2 Monomer component Rubber (part) Graft Intrinsic polymer
Acrylo- ratio viscosity Kind Part Styrene nitrile (%) [.eta.]
(dl/g) A1-1 (a-1) 30 49 21 115 -- A1-2 (a-1) 40 42 18 68 -- A'1-1
(a-1) 50 35 15 18 -- A'1-2 (a-1) 30 49 21 160 -- A'1-3 (a-2) 30 49
21 105 -- A'1-4 (a-2) 40 42 18 80 -- A'1-5 (a-3) 30 49 21 102 --
A'1-6 (a-3) 40 42 18 83 -- A2-1 -- -- 70 30 -- 0.56 A2-2 -- -- 75
25 -- 0.51 A2-3 -- -- 70 30 -- 0.71 A2-4 -- -- 75 25 -- 0.41
Reference Example 3
Preparation of Phosphorus-based Flame Retardant
[0100] The following condensed phosphoric acid esters (B-1) to
(B-5) and phosphazene compound (B-6) were used as the component
(B).
[0101] (B-1): Condensed phosphoric acid ester represented by the
above general formula (I) wherein R.sup.1 to R.sup.4 are phenyl; X
is a residue of bisphenol A; and n is 1.1.
[0102] (B-2): Condensed phosphoric acid ester represented by the
above general formula (I) wherein R.sup.1 to R.sup.4 are
2,6-xylenyl; X is a residue of resorcinol; and n is 1.0.
[0103] (B-3): Condensed phosphoric acid ester represented by the
above general formula (I) wherein R.sup.1 to R.sup.4 are phenyl; X
is a residue of bisphenol A; and n is 0.6.
[0104] (B-4): Triphenyl phosphate represented by the above general
formula (I) wherein R.sup.1 to R.sup.4 are phenyl; and n is 0.
[0105] (B-5): Condensed phosphoric acid ester represented by the
above general formula (I) wherein R.sup.1 to R.sup.4 are phenyl; X
is a residue of bisphenol A; and n is 0.3.
[0106] (B-6): Phenoxy phosphazene represented by the following
formula (IV ) (a mixture of (y=1) and (y=2) compounds): 4
Reference Example 4
Preparation of Component (C)
[0107] As the component (C), there was used ethylene
bis-stearylamide produced by Kao Co., Ltd.
Examples 1 to 8 and Comparative Examples 1 to 12
[0108] The respective components were mixed together for 3 minutes
at mixing ratios shown in Tables 3 to 5 using a Henschel mixer.
Then, the resultant mixture was melt-extruded from an NVC-type
50-mm vented extruder manufactured by Nakatani Kikai Co., Ltd., by
setting the cylinder temperature to 180 to 220.degree. C., thereby
obtaining pellets. The thus obtained pellets were sufficiently
dried, and then injection-molded using an injection molding machine
J100E-C5 manufactured by Nippon Seikosho Co., Ltd., by setting the
cylinder temperature and mold temperature to 200.degree. C. and
50.degree. C., respectively, thereby obtaining test specimens for
various evaluation tests. The test specimens were tested by the
above evaluation methods. The results are shown in Tables 3 to
5.
3TABLE 3 Composition Examples (part) 1 2 3 4 5 6 7 8 Component (A)
(A1-1) 40 -- 30 30 20 -- 40 40 (A1-2) -- 45 -- 10 20 40 -- --
(A2-1) 50 -- 70 60 60 60 60 60 (A2-2) -- 55 -- -- -- -- -- --
Properties of component (A) Rubber content 12 18 9 13 14 16 12 12
(%) Graft ratio (%) 115 68 115 101 88 68 115 115 Component (B)
(B-1) (n = 1.1) 10 -- 6 -- 12 -- -- 10 (B-2) (n = 1.0) -- 14 -- 12
-- -- -- -- (B-3) (n = 0.6) -- -- -- -- -- 10 -- -- (B-4) (n = 0)
-- -- -- -- -- -- -- -- (B-5) (n = 0.3) -- -- -- -- -- -- -- --
(B-6) -- -- -- -- -- -- 10 -- Component (C) 2 2 3 0.5 2 1 2 --
Evaluation results Fluidity 49 42 73 35 41 49 44 46 (g/10 min.)
Izod impact 14 19 10 15 17 23 15 16 strength (J/m) Heat 83 81 79 82
83 80 79 80 deformation temperature (HDT) (.degree. C.) Burning V-2
V-2 V-2 V-2 V-2 V-2 V-2 V-2 property Falling weight 390 450 430 390
380 450 390 410 impact strength
[0109]
4 TABLE 4 Comparative Examples Composition (part) 1 2 3 4 5 6
Component (A) (A1-1) 20 -- 30 50 -- -- (A1-2) -- 55 -- -- -- --
(A'1-1) -- -- -- -- 20 -- (A'1-2) -- -- -- -- -- 50 (A2-1) 60 -- 70
50 80 50 (A2-2) -- -- -- -- -- -- (A2-3) 20 -- -- -- -- -- (A2-4)
-- 45 -- -- -- -- Properties of component (A) Rubber content (%) 6
22 9 15 10 15 Graft ratio (%) 115 68 115 115 48 135 Component (B)
(B-1) (n = 1.1) -- 8 4 21 10 7 (B-2) (n = 1.0) 15 -- -- -- -- --
(B-3) (n = 0.6) -- -- -- -- -- -- (B-4) (n = 0) -- -- -- -- -- --
Component (C) 1.5 1 2 3 2 2 Evaluation results Fluidity (g/10 min.)
71 32 65 58 72 36 Izod impact strength 4 28 13 18 6 24 (J/m) Heat
deformation 79 85 87 70 81 83 temperature (HDT) (.degree. C.)
Burning property V-2 B B V-2 V-2 B Falling weight 90 120 110 115 85
110 impact strength
[0110]
5 TABLE 5 Comparative Examples Composition (part) 7 8 9 10 11 12
Component (A) (A1-1) -- -- -- -- 20 20 (A1-2) -- -- -- -- 20 20
(A'1-3) 45 -- -- -- -- -- (A'1-4) -- 40 -- -- -- -- (A'1-5) -- --
45 -- -- -- (A'1-6) -- -- -- 40 -- -- (A2-1) 55 60 55 60 60 60
Properties of component (A) Rubber content (%) 14 16 14 16 14 14
Graft ratio (%) 105 80 102 83 88 88 Component (B) (B-1) (n = 1.1)
-- 10 10 10 -- -- (B-2) (n = 1.0) 10 -- -- -- -- -- (B-3) (n = 0.6)
-- -- -- -- -- -- (B-4) (n = 0) -- -- -- -- 12 -- (B-5) (n = 0.3)
-- -- -- -- -- 12 Component (C) 2 2 2 2 1 1 Evaluation results
Fluidity (g/10 min.) 38 44 47 42 79 76 Izod impact strength 13 12
14 11 15 16 (J/m) Heat deformation 84 82 81 80 72 73 temperature
(HDT) (.degree. C.) Burning property V-2 V-2 V-2 V-2 V-2 V-2
Falling weight 120 90 70 105 300 310 impact strength
[0111] As is apparent from Examples 1 to 8, the resin compositions
of the present invention all were excellent in impact resistance,
heat resistance and flame retardancy.
[0112] On the other hand, the resin composition obtained in
Comparative Example 1 in which the content of the rubber polymer in
the component (A) was reduced out of the range defined by the
present invention, was deteriorated in impact resistance. The resin
composition obtained in Comparative Example 2 in which the content
of the rubber polymer in the component (A) was increased out of the
range defined by the present invention, was deteriorated in flame
retardancy. The resin composition obtained in Comparative Example 3
in which the amount of the component (B) blended was reduced out of
the range defined by the present invention, was deteriorated in
flame retardancy. The resin composition obtained in Comparative
Example 4 in which the amount of the component (B) blended was
increased out of the range defined by the present invention, was
deteriorated in heat resistance. The resin composition obtained in
Comparative Example 5 in which the graft ratio of the rubber
polymer in the component (A) was reduced out of the range defined
by the present invention, was deteriorated in impact resistance.
The resin composition obtained in Comparative Example 6 in which
the graft ratio of the rubber polymer in the component (A) was
increased out of the range defined by the present invention, was
deteriorated in flame retardancy.
[0113] In Comparative Examples 7 and 8, the particle size
distribution of the rubber polymer in the component (A) was out of
the range defined by the present invention. Namely, in these
Comparative Examples, the rubber polymer particles having a
particle size of not more than 150 nm were blended in a too large
amount, and those having a particle size of from more than 150 nm
to less than 350 nm were blended in a too small amount. The resin
compositions obtained in Comparative Examples 7 and 8 were
deteriorated in falling weight impact strength.
[0114] In Comparative Examples 9 and 10, the particle size
distribution of the rubber polymer in the component (A) was out of
the range defined by the present invention. Namely, in these
Comparative Examples, the rubber polymer particles having a
particle size of from more than 150 nm to less than 350 nm were
blended in a too small amount, and those having a particle size of
not less than 350 nm were blended in a too large amount. The resin
compositions obtained in Comparative Examples 7 and 8 were also
deteriorated in falling weight impact strength.
[0115] The resin compositions obtained in Comparative Examples 11
and 12 in which the value "n" of the condensed phosphoric acid
ester contained in the component (B) was reduced out of the range
defined by the present invention, was deteriorated in heat
resistance.
* * * * *