Note: Descriptions are shown in the official language in which they were submitted.
MBR-8146
2 ~
RESIN COMPOSITION HAVING GOOD ANTISTATIC PROPERTY
BACKGROUND OF THE INVENTION
- (1) Field of the Invention
This invention relates to a resin composition
having a good antistatic property and heat resistance,
which comprises a specific methacrylimide group-con-
taining polymer, and incorporated therein, a specific
polyhydric alcohol compound and/or a compound having
polyoxyethylene segments.
(2) Description of the Related Art
A methacrylimide group-containing polymer has
a good heat resistance and transparency, a relatively
high heat distortion temperature, a good rigidity,
surface hardness, and molding processability, but this
polymer has a problem in that the electric resistance
value is large and the polymer is easily statically
charged by for example, rubbing or peeling.
A method of an internal kneading of an
antistatic agent is generally adopted for imparting an
antistatic property to plastics, and in this method, an
antistatic agent having a good compatibility with a base
resin must be selected. If an antistatic agent having a
poor compatibility with the base resin is used, problems
such as a sticky surface and the precipitation of a
white powder are caused by an excessive migration or
bleeding of the antistatic agent to the surface, and
furthermore, the inherent transparency of the resin
becomes poor. In contrast, if an antistatic agent
having a good compatibility with the base resin is used,
the antistatic agent is uniformly dispersed in the
resin, and a substantial antistatic effect is not
manifested.
A methacrylimide group-containing polymer has
a relatively high glass transition temperature, and
therefore, a migration of an antistatic agent to the
surface becomes more difficult. Moreover, since the
-- 2 --
molding temperature of this polymer is high, the
antistatic agent per se must have a high hea~ stability.
Namely, appropriate antistatic agents must be
developed for respective base resins, but an antistatic
agent effective for the methacrylimide group-containing
polymer has not been developed.
A resin composition comprised of a
methacrylimide group-containing polymer and a fatty acid
glyceride ester is described in Japanese Unexamined
Patent Publication No. 64-75290. It is taught that this
resin composition has an improved moldability as
compared with a methacrylimide group-containing polymer,
but this publication is silent on the antistatic
property thereof.
A resin material having an antistatic proper~y
and a good heat resistance has not been known, and a
development of this resin material is required.
SUMMARY OF THE INVENTION
A primary object of the present invention is to
obviate the defect of a methacrylimide group-containing
polymer, and provide a resin composition having a good
antistatic property and a high heat resistance.
In accordance with the present invention, there is
provided a resin composition having a good antistatic
property and heat resistance, which comprise~ (A) l00
parts by weight of a polymer comprising at least 10% by
weight of methacrylimide units represented by the
following general formula (I):
CH CH
~ 1 / CH~ / CH~
0~ \ N~ O
wherein Rl represents a hydrogen atom or an
aliphatic, aromatic or alicyclic hydrocarbon having
l to 20 carbon atoms,
2 ~ i~)
and (B) 0.5 to 20 parts by weight of at least one
compound selected from polyhyclric alcohol compounds and
compounds having polyoxyethylene segments, which are
represented by the following general formulae (II)
through (X):
OH OH
R2 C 2 2 (II),
O CH OH
~ 1 2
R3-c-o-cH2-c-cH2oH (III),
CH2H
o OH
R4-C-OCH2-CH-CIH IH2 (IV),
HO- H-CH-OH
o
R5-c-o-cH2-cH \ CH2 (V),
HO/ ~CH/ OH
OH
O CH2OH
R6-C-OCH2C-CH2CH3 (VI),
C 2
R7~C~~(CH2CH2 ~ R8 (VII),
Rg~O-t-CH2CH2O ~ Rlo (VIII),
/(CH2cH2 ~ R12 (IX),
\(CH2CH2O ~d R13
and
-- 4 --
Rl4-c-O-fH2
HC-O ~ CH2CH20 ~ -R15 (X),
H2C-0--tCH2CH20 ~ Rl6
wherein R2 through R7 , Rg , Rll and Rl4 represent
an alkyl group having 8 to 22 carbon atoms, R8 ~
l0 ' Rl2 ~ Rl3 ~ Rl5 ~ Rl6 represent a hydrogen
atom or an alkyl group having up to 22 carbon
atoms, and a, b, c, d, e, and f are integers of
from 1 to 200, with the proviso that the sum of c
and d is in the range of from 2 to 200 and the sum
of e and f is in the range of from 2 to 200.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The methacrylimide group-containing polymer used as
the component (A) in the present invention comprises
methacrylimide units as represented by general
formula (I), and the poly~er (A~ can be either a
homopolymer or a copolymer. In general formula (I), R
preferably represents a hydrogen atom, a methyl group,
an ethyl group, a propyl group, a butyl group or a
0 phenyl group.
The methacrylimide group-containing polymer used in
the present invention comprises at least 10% by weight,
preferably at least 20% by weight, of the above-
mentioned methacrylimide units. If the content of the
methacrylimide units is lower than 10% by weight, the
high heat resistance inherently possessed by this
polymer is substantially not manifested.
The-methacrylimide group-containing polymer (A) may
contain units which have not been imidized when a
methacrylic polymer is subjected to imidization~ Such
groups include, for example, units derived from an alkyl
methacrylate such as methyl methacrylate and units
derived from an alkyl methacrylate and another
ethylenically unsaturated monomer.
~ r~ ~ f, ,~ r~ ~
The process for the preparation of the meth-
acrylimide group-containing polymer used in the present
invention is not particularly critical. For example,
there can be advantageously adopted a process comprising
S reacting at an elevated temperature a methacrylic resin
such as polymethyl methacrylate with ammonia or a
primary amine such as methylamine or ethylamine in an
appropriate solvent, for example, an aromatic hydro-
carbon such as benzene, toluene or xylene, an alcohol
such as methanol, ethanol or propanol, or a mixed
solvent of at least two solvents selected from these
aromatic hydrocarbons and alcohols, at a temperature of
170 to 350C, preferably 200 to 300C, in an autoclave.
Furthermore, the reaction can be carried out in an
extruder, as disclosed in Japanese Unexamined Paten~
Publication No. 52-63989.
At least one compound selected from polyhydric
alcohol compounds and compounds having polyoxyethylene
segments, which are represented by general formulae (II)
through (X), are used as the component (B). As the
compound (B), there can be mentioned fatty acid/ethylene
oxide adducts, aliphatic alcohol/ethylene oxide adducts,
fatty acid amide/ethylene oxide adducts, glycerol
monofatty acid ester/ethylene oxide adducts, glycerol
monoaliphatic ethers, pentaerythritol monofatty acid
esters, sorbitol monofatty acid esters, and trimethylol~
propane monofatty acid esters. Fatty acids and
aliphatic alcohols in these compounds are those having 8
to 22 carbon atoms, and as specific examples, there can
be mentioned octanoic acid, lauric acid, myristic acid,
palmitic acid, stearic acid, montanic acid, oleic acid,
behenic acid, octyl alcohol, lauryl alcohol, stearyl
alcohol, and behenyl alcohol. If a fatty acid or
aliphatic alcohol having up to 7 carbon atoms is used,
the compatibility of the compound (B) with the base
resin is poor and surging occurs in an extruder at the
pellet-making step. In view of the stability of
ç~;p r~ c~
-- 6 --
manifestation of the antistatic property, a compound (B)
comprising stearic acid or stearyl alcohol is preferably
used, and glycerol m~nostearyl ether is especially
preferably used.
The number of added ethylene oxide units is 1 to
200 per molecule of the compound (B). If the number of
added ethylene oxide units is larger than 200, the
antistatic property of the obtained resin composition
becomes poor.
The compound (B) is incorporated in an amount of
0.5 to 20 parts by weight, preferably 2 to 15 parts by
weight, more preferably 5 to lO parts by weight, per
100 parts by weight of the methacrylimide group-con-
taining polymer. If the amount of the compound (B)
added is smaller than 0.5 part by weight, a substantial
antistatic effect is not manifested. Incorporation of
the compound (B) in an amount exceeding 20 parts by
weight is not preferred from the economical viewpoint.
In view of the stability of the manifestation of the
antistatic effect, most preferably the compound (B) is
incorporated in an amount of 5 to 10 parts by weight.
The resin composition of the present invention is
characterized in that the heat distortion temperature of
the resin composition can be optionally adjusted
according to the structure and content of the meth-
acrylimide units in the methacrylimide group-containing
polymer (A) and the amount of the compound (B) added.
heat distortion temperature of about 100C is generally
sufficient for ordinary use, and a resin composition
having such a heat distortion temperature can be shaped
under shaping conditions customarily adopted for
methacrylic resins and the like. When the resin
composition is used in fields where a high heat
resistance is required, the heat distortion temperature
35 can be adjusted to 100 to 170C. Namely, the heat
resistance of the resin composition can be freely
adjusted according to the intended use.
-- 7
The composition of the present invention can be
prepared by melt-kneading the methacrylimide group-con-
taining polymer (A) together with the compound (B) in an
extruder or the like. A part or all of the compound (B)
can be added at the step of preparing the acrylimide
group-containing polymer (A). In general, the former
process is preferably adopted, in view of the stability
of the methacrylimide group-containing polymer.
The thermal decomposition-preventing agent, an
anti-oxidant, and an ultraviolet absorber can be
incorporated in the resin composition of the present
invention, to improve the heat resistance, light
resistance, and resistance to oxidative deterioration.
Furthermore, a plasticizer, a dye, a lubricant and the
like can be incorporated in the resin composition of the
present invention.
The resin composition of the present invention can
be shaped into various articles by known plastic shaping
methods such as press molding, injection molding and
~o extrusion shaping.
The present invention will now be described in
detail with reference to the following examples.
In the following examples and comparative examples,
all of "parts" and "%~ are by weight.
In the examples and comparative examples, the
physical properties of polymers were determined
according to the following methods.
(l) Heat distortion temperature
The heat distortion temperature was determined
according to ASTM D-648-56 under a load of 18.6 kg/cm~.
(2) Imidization degree (%) of methacrylimide
group-containing polymer
The imidization degree (%) was determined ~rom
the nitrogen content in the elementary analysis values
measured by a CHN coder (MT-3 supplied by Yanagimoto
Seisakusho) and the proton NMR spectrum measured by a
spectrometer lOO MHz (JNM-F~-lOO supplied by JEOI,).
2 ~
(3) Surface resistance value
A sample was subjected to moisture condi-
tioning at a temperature of 20C and a relative humidity
of 65% for l day, a voltage o:E 500 V was applied to the
sample at a temperature of 20C and a relative humidity
of 65% for l minute, and the surface resistance value
(n) was measured by a high megohm meter (TR-8601
supplied by Takeda-Riken).
(4) Charge half-value time
A sample was subjected to moisture condi-
tioning at a temperature of 20~C and a relative humidity
of 65% for l day, and the charye was measured under an
applied voltage of lO,000 V at a sample rotating speed
of l,300 rpm, a temperature of 20C and a relative
humidity of 65% for an application time of 30 seconds.
The time required for the sample voltage to drop to l/2
of the initial voltage after the application of the
voltage was stopped was measured by using a static
honest meter (supplied by Shishido Shokai) and desig-
nated as the charge half-value times (seconds). Note,
change half-value times longer than 2 minutes are
indicated by the mark "~".
(5) Transparency
The transparency was evaluated based on the
haze value measured by an integrating sphere haze meter
(SEP-H-SS supplied by Nippon Seimitsu Kogaku).
(6) Inherent viscosity of polymer
The flow time (ts) of a chloroform solution
having a sample pol~mer concentration of 0.5% by weight
and the flow time (to) of chloroform were measured at a
temperature of 25C + 0.1C by a Deereax-Bishoff
viscometer, the relative viscosity ~rel of the polymer
was determined from the value of ts/to, and the inherent
viscosity was calculated according to the following
formula:
Inherent viscosity = lim(ln~rel)/C(d~/g)
C-O
2~3~
wherein C represents the number of grams of the
polymer in lO0 ml of the solvPnt.
Referential Example A (preparation of
methacrYlimide-containinc~ polymers~
Referential Example A-1
A lO-liter reaction vessel equipped with a paddle
spiral agitator, a pressure gauge, a sample injector,
and a jacket heater was charged with 100 parts of a
thoroughly dried methyl methacrylate polymer having an
inherent viscosity of 0.51, 90 parts of toluene and 10
parts of methanol, and the inner atmosphere was replaced
by nitrogen. The temperature was elevated to 200C and
the mixture was stirred to prepare a solution. Then,
21.7 parts ~molar ratio = 0.7) of methylamine was added
to the solution from the sample injector. The reaction
was carried out under heating and an inner pressure of
60 kg/cm2 for 3 hours, and a methacrylimide group-con-
taining polymer (A-1) was obtained by this reaction.
The polymer was dried and powdered to obtain a sample.
Referential ExamPle A-2
A methacrylimide group-containing polymer (A-2) was
prepared in the same manner as described in Example 1,
except that 24.8 parts (molar ratio = 0.8) of methyl-
amine was used.
Referential ExamPle A-3
A methacrylimide group-containing polymer (A-3) was
prepared in the same manner as described in Example l,
except that 15.5 parts (molax ratio = 0.5) of methyl-
amine was used.
Referential Example A-4
A methacrylimide group-containing polymer (A-4) was
prepared in the same manner as described in Example 1,
except that 12.4 parts (molar ratio = 0.4) of methyl-
amine was used.
Referential Example A-5
A methacrylimide group-containing polymer (A-5) was
prepared in the same manner as described in Example 1,
-- 10 --
except that ammonia was used at a molar ratio of 0.7
instead of methylamine.
The characteristics of the methacrylimide group-
containing polymers A-1 through A-5 prepared in
Referential Examples A-l through 5 were evaluated. The
results are shown in Table 1.
Table 1
.
Referential Starting Imidiza- Heat dis-
Example polymer for tion tortion
No. imidization degree temperature
reaction (~) (C)
A-l MMA polymer 80 140
A-2 MMA polymer 88 150
A-3 MMA polymer 73 130
A-4 MMA polymer 65 120
A-S MMA polymer 73 190
Referential Example B
The following compounds were used as the compound
(B) in the examples given hereinafter.
B-l: glycerol monostearyl ether
B-2: glycerol mono-octyl ether
B-3: glycerol monobehenyl ether
B-4: pentaerythritol monostearate
B-5: sorbitol monostearate
B-6: trimethylolpropane monostearate
B-7- 10-mole ethylene oxide adduct to stearic acid
B-8: 9-mole ethylene oxide adduct to lauryl
alcohol
B-9: 20-mole ethylene oxide adduct to behenyl
alcohol
B-10: 15-mole ethylene oxide adduct to stearic
acid amide
B~ 2-mole ethylene oxide adduct to glycerol
monostearate
B-12: 5-mole ethylene oxide adduct to glycerol
monostearate
B-13: 55-mole ethylene oxide adduct to stearic
acid
Examples l th.rouqh 13
a composition prepared by incorporating 10 parts of
a compound (B) shown in Referential Example B in the
methacrylimide group-containing polymer (A-1) obtained
in Referential Example A-l was extrusion-shaped into a
pellet.
The pellet was injection-molded under the injection
molding conditions shown below to form a test piece for
the e~aluation of the heat resistance and a flat test
piece. The heat distortion temperature, antistatic
property, and transparency were determined, and the
results are shown in Table 2.
(Injection Molding Conditions)
Injection molding machine: Promat 165/75 supplied
by Sumitomo Juki
Molding temperature: 100C
Injection molding temperature: 300C
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Examples 14 throuah 17 and ComParative Examples 1
throuqh 5
A resin composition prepared by incorporating 10
parts of a compound (B-l) shown in Referential Example
(B) in lO0 parts of the methacrylimide group-containing
polymer (A) obtained in Referential Example A-2, A-3,
A-4 or A-5 was molded into test pieces for the measure-
ment of various physical properties by injection molding
cylinder temperature 320C, mold temperature 100C).
The results of the measurement of the physical pro-
perties are shown in Table 3.
For comparison, the methacrylimide group-containing
polymers (A-1) through (~-5) obtained in Referential
Examples A-l through A-5 were independently molded
without incorporation of the compound (B), and the
physical properties were similarly evaluated. The
results are shown in Table 3.
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- 14 -
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- 15 -
Examples 18 throuqh 23
A composition prepared by incorporating the
compound (B-1) shown in Referential Example B in an
amount shown in Thble 4 in 100 parts of the methacryl-
imide group~containing polymer (A-l) or (A-5) obtained
in Referential Example A-1 or A-5 was molded into a test
piece in the same manner as described in Example 1, and
the various physical properties were measured. The
results are shown in Table 4.
- 16 -
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- 17 -
Comparative Example fi
A composition prepared by incorporating 10 parts of
a cationic antistatic agent (Duspar 125B supplied by
Miyoshi Yushi) in 100 parts of the methacrylimide
group-containing polymer (A-1) obtained in Referential
Example A-1 was molded into a test piece in the same
manner as described in Example 1, and the physical
properties were evaluated.
It was found the surface resistance value was
larger than 1 x 1015 n, the charge half-value time
was ~, and the haze value was 61%, and thus it was
confirmed that a substantial antistatic effect was not
manifested and that the transparency became poor. The
molded article was discolored yellow, and had no
commercial value.
Comparative Example 7
A composition formed by incorporating 5 parts of a
cationic antistatic agent (Duspar 125B supplied by
Miyoshi Yushi) in 100 parts of the methyl methacrylate
polymer used in Referential Example A was extrusion-
shaped into a pellet, and the pellet was molded into
test pieces for the measurement of the physical
properties by injection molding ~cylinder temperature
230C, mold temperature 70C), and the physical
properties were evaluated.
It was found that the surface resistance value was
8.9 x 1011 ~, the charge half-value time was 2.1
seconds, the haze value was lower than 2.0%, and the
heat di~tortion temperature was 85C, and it was
confirmed that a good antistatic property and a high
transparency were manifested.
When Comparative Example 7 is compared with
Comparative Example 6, it is seen that the methacryl-
imide group-containing polymer obtained by the
imidization is quite different from the starting methyl
methacrylate polymer in the compatibility thereof with
additives and other properties.
~3~
- 18 -
According to the present invention, by incorpo-
rating a specific compound in a specific methacrylimide
group-containing polymer, a resin composition having a
good antistatic property and heat resistance can be
obtained, and due to these good properties, the resin
composition of the present invention can be advanta-
geously used for the production of illuminating
articles, covers and parts of electric devices and
electronic instruments, meter covers, daily necessities,
sheets, panels, and the like.
