[0001]The present invention relates to an olefin-based polymer composition.
Background Art
[0002]It is known that a lubricant is added to an olefin-based thermoplastic polymer
composition. According to the technique disclosed in Patent Literature 1, higher fatty acid
amide is added as a lubricant in order to acquire mold releasability when removing a formed
product from a mold and slidability on the surface of a formed product.
[0003]
The technique disclosed in Patent Literature 1 concerns a thermoplastic elastomer
obtained by subjecting a composition supplemented with a lubricant to dynamic heat treatment
in the presence of an organic peroxide and a crosslinking aid.
Citation List
Patent Literature
[0004]
Patent Literature 1: JP H11-208404 A (1999) (Claim 1; Paragraph [0019])
Summary of Invention
Technical Problem
[0005]
On the basis of the finding of the present inventors, it is considered that a composition
that contains a cross-linked product is naturally excellent in terms of mold releasability because
of the cross-linked product. In the case of a composition that does not contain a cross-linked
product, in contrast, it is necessary to improve mold releasability with the addition of a lubricant
in order to produce a formed product smoothly. When the amount of the lubricant added is
increased, however, poor appearance or deteriorated anti-fogging properties caused by bleeding
2
becomes problematic.
[0006]
It is an object of the present invention to provide an olefin-based polymer composition
that does not contain a cross-linked product but has achieved excellent mold releasability with
the addition of a small amount of a lubricant.
Solution to Problem
[0007]
The present invention is summarized as follows.
(1) A polymer composition comprising:
(A) 65 to 35 parts by mass of a copolymer containing a constitutional unit derived
from ethylene and a constitutional unit derived from an -olefin having 3 to 20 carbon atoms;
(B) 35 to 65 parts by mass of a propylene-based polymer having a melting point of
135°C to 170°C measured by DSC (provided that the total of the component (A) and the
component (B) is 100 parts by mass);
(C) 0.01 to 0.50 parts by mass of fatty acid amide with a molecular weight of 310 to
5,000 relative to 100 parts by mass of the total of the component (A) and the component (B);
and
(D) 0.01 to 0.50 parts by mass of fatty acid amide with a molecular weight of 298 or
less relative to 100 parts by mass of the total of the component (A) and the component (B),
wherein, when the amount of the component (C) is designated Wc and the amount of
the component (D) is designated Wd, Wc/Wd is 0.5 to 1.5, and the component (A) is not
crosslinked.
(2) The polymer composition according to (1), wherein the amount of the component (C)
added and the amount of the component (D) added are each 0.10 to 0.50 parts by mass.
(3) The polymer composition according to (1) or (2), wherein the component (C) and the
component (D) are each linear fatty acid amide.
(4) The polymer composition according to any of (1) to (3), wherein the component (C)
is erucic acid amide.
(5) The polymer composition according to any of (1) to (4), wherein the component (D)
is oleic acid amide.
3
(6) A formed product prepared from the polymer composition according to any of (1) to
(5).
(7) A method for producing an injection-molded product comprising subjecting the
polymer composition according to any of (1) to (5) to injection molding.
Advantageous Effects of the Invention
[0008]
The present invention can provide an olefin-based polymer composition that does not
contain a cross-linked product but has achieved excellent mold releasability with the addition
of a small amount of a lubricant.
Description of Embodiments
[0009]

In the present invention, a copolymer containing a constitutional unit derived from
ethylene and a constitutional unit derived from an -olefin having 3 to 20 carbon atoms used
as the component (A) (hereinafter referred to as an "ethylene-based copolymer (A)") is
preferably a copolymer mainly composed of ethylene and an -olefin having 3 to 20 carbon
atoms. Examples thereof include an amorphous random copolymer composed of ethylene and
an -olefin having 3 to 20 carbon atoms and an amorphous random copolymer composed of
ethylene, an -olefin having 3 to 20 carbon atoms, and a non-conjugated polyene. From the
viewpoint of heat stability, an amorphous random copolymer that does not contain a
constitutional unit derived from polyene is preferable.
[0010]
Examples of the above -olefin include, for example, propylene, 1-butene, 1-pentene,
1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 2-methyl-1-propene, 3-methyl-1-pentene,
4-methyl-1-pentene, and 5-methyl-1-hexene. Among these, propylene, 1-butene, 4-methyl-1-
pentene, 1-hexene, and 1-octene are preferable. 1-Butene is particularly preferable. These
-olefins are used singly or as a mixture of two or more.
[0011]
The molar ratio of ethylene to an -olefin having 3 to 20 carbon atoms in the ethylene4
based copolymer (A) is usually 55/45 to 85/15, preferably 60/40 to 83/17.
[0012]
Examples of the above non-conjugated polyene include, for example, cyclic dienens
such as dicyclopentadiene, cyclooctadiene, methylenenorbornene (for example, 5-methylene-
2-norbornene), ethylidenenorbornene (for example, 5-ethylidene-2-norbornene),
methyltetrahydroindene, 5-vinyl-2-norbornene, 5-isopropylidene-2-norbornene, 6-
chloromethyl-5-isopropenyl-2-norbornene and norbornadiene; chain dienes such as 1,4-
hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4,5-
dimethyl-1,4-hexadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 6-ethyl-1,6-
octadiene, 6-propyl-1,6-octadiene, 6-butyl-1,6-octadiene, 6-methyl-1,6-nonadiene, 7-methyl-
1,6-nonadiene, 6-ethyl-1,6-nonadiene, 7-ethyl-1,6-nonadiene, 6-methyl-1,6-decadiene, 7-
methyl-1,6-decadiene, 6-methyl-1,6-undecadiene and 7-methyl-1,6-octadiene; and trienes such
as 2,3-diisopropylidene-5-norbornene and 2-ethylidene-3-isopropylidene-5-norbornene. In
the case of comprising the non-conjugated polyene, the iodine value of the ethylene-based
copolymer (A) is usually 0.1 to 20, preferably 1 to 20.
[0013]
As the ethylene-based copolymer (A), ethylene-1-butene copolymer is preferable.
[0014]
The density of the ethylene-based copolymer (A) is usually 850 to 870 kg/m3,
preferably 855 to 870 kg/m3.
[0015]
The MFR (ISO1133, 190C, load 2.16 kg) of the ethylene-based copolymer (A) is
usually 0.1 to 50 g/10 min, preferably 0.1 to 10 g/10 min.
[0016]
The MFR (ISO1133, 230C, load 2.16 kg) of the ethylene-based copolymer (A) is
usually 0.2 to 100 g/10 min, preferably 0.2 to 20 g/10 min.
[0017]
The Mooney viscosity [ML1+4 (125C)] of the ethylene-based copolymer (A) is usually
35 to 300, preferably 40 to 160.
[0018]
5
Concerning the ethylene-based copolymer (A), a melting point (Tm) measured by
differential scanning calorimetry (DSC) is preferably 170°C or lower (more preferably 100°C
or lower, and further preferably 90°C or lower) or not detected. When a "melting point is not
detected" herein, the heat of fusion (ΔH) is less than 1 J/g.
[0019]
The ethylene-based copolymer (A) used in the present invention may be a so-called
"oil-extended rubber" produced with the addition of a softening agent (preferably a mineral oilbased
softening agent). Examples of mineral oil-based softening agents include known
mineral oil-based softening agents, such as paraffin-based process oil.
[0020]
The amount of the ethylene-based copolymer (A) added is 35 to 65 parts by mass, and
preferably 45 to 60 parts by mass, relative to 100 parts by mass of the total of the ethylenebased
copolymer (A) and the propylene-based polymer (B). When the amount of the ethylenebased
copolymer (A) added is less than 35 parts by mass, disadvantageously, rigidity may be
enhanced and impact resistance at low temperature may be deteriorated to a significant extent.
When such amount exceeds 65 parts by mass, flowability or crystallinity may become
insufficient, and the composition may not be suitable for injection molding.
[0021]
In the present invention, it is necessary that the ethylene-based copolymer (A) is not
crosslinked from the viewpoint of mold releasability achieved with the aid of a lubricant.
[0022]

Examples of the propylene-based polymer used as the component (B) in the present
invention (hereinafter referred to as "propylene-based polymer (B)") include a crystalline highmolecular-
weight solid product obtained by polymerization of propylene alone or
polymerization of propylene with another monoolefin or two or more other monoolefins by a
high pressure process or low pressure process. Examples of such polymers include an
isotactic monoolefin polymer and a syndiotactic monoolefin polymer.
[0023]
The propylene-based polymer (B) may be synthesized in accordance with a
6
conventional technique, or a commercially available product may be used.
[0024]
The propylene-based polymer (B) may be used alone or in combinations of two or
more.
[0025]
A preferable starting material olefin for the propylene-based polymer (B) other than
propylene is an α-olefin having 2 or 4 to 20 carbon atoms. Specific examples thereof include
ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 2-methyl-1-propene, 3-methyl-1-
pentene, 4-methyl-1-pentene, and 5-methyl-1-hexene. Such -olefin having 2 or 4 to 20
carbon atoms may be used alone or in combinations of two or more. The form of
polymerization may be random type or block type as long as a resinous product can be obtained.
These propylene-based polymers can be used alone or in combinations of two or more.
[0026]
The propylene-based polymer (B) generally has MFR (ISO1133, 230°C, load 2.16 kg)
of 20 to 200 g/10 min, and preferably 40 to 70 g/10 min, from the viewpoint of injection
moldability and impact resistance at low temperature.
[0027]
Concerning the propylene-based copolymer (B), a melting point (Tm) measured by
differential scanning calorimetry (DSC) is 135°C to 170°C, and preferably 155°C to 165°C.
When the melting point (Tm) is lower than 135°C, impact resistance at low temperature may
be improved while rigidity may be deteriorated. When the melting point is over 170°C,
rigidity may be enhanced while impact resistance at low temperature may be deteriorated.
[0028]
The density of the propylene-based polymer (B) is generally 890 to 910 kg/m3, and
preferably 900 to 910 kg/m3.
[0029]
The propylene-based polymer (B) improves flowability and heat resistance of the
olefin-based polymer composition.
[0030]
The amount of the propylene-based polymer (B) added is 35 to 65 parts by mass, and
7
preferably 40 to 55 parts by mass, relative to 100 parts by mass of the total of the ethylenebased
copolymer (A) and the propylene-based polymer (B). When the amount of the
propylene-based polymer (B) added is less than 35 parts by mass, disadvantageously,
flowability may become insufficient, and the composition may not be suitable for injection
molding. When such amount exceeds 65 parts by mass, rigidity may be enhanced while
impact resistance at low temperature may be deteriorated to a significant extent.
[0031]

In the present invention, fatty acid amides are used as the component (C) and the
component (D).
When a fatty acid amide as the component (C) or the component (D) is branched, such
fatty acid amide is likely to remain inside the resin. In the present invention, accordingly,
fatty acid amides used as the component (C) and the component (D) are preferably linear fatty
acid amides, so that fatty acid amides would not remain inside the resin, they would adequately
bleed on the resin surface at the time of molding, and the targeted mold releasability would be
achieved.
[0032]

In the present invention, fatty acid amide used as the component (C) (hereinafter
referred to as "fatty acid amide (C)") has a molecular weight of 310 to 5,000. Any fatty acid
amide that can function as a lubricant can be used without particular limitation. Examples
thereof include unsaturated fatty acid amide, saturated fatty acid amide, substituted amide,
methylol amide, saturated bisamide, and unsaturated bisamide. A molecular weight of fatty
acid amide (C) is preferably 310 to 691, more preferably 310 to 400, and further preferably 310
to 340.
[0033]
Specific examples of fatty acid amide (C) include erucic acid amide (molecular weight:
338), behenic acid amide (molecular weight: 340), and hexamethylene bis behenic acid amide
(molecular weight: 691), with erucic acid amide and behenic acid amide being preferable.
[0034]
8
The amount of fatty acid amide (C) added is 0.01 to 0.50 parts by mass, preferably
0.10 to 0.50 parts by mass, and more preferably 0.10 to 0.30 parts by mass, relative to 100 parts
by mass of the total of the ethylene-based copolymer (A) and the propylene-based polymer (B).
When the amount of fatty acid amide (C) added is less than 0.01 parts by mass, the amount
thereof remaining on the resin surface is small at the time of molding, and it would not
contribute to achieve sufficient mold releasability. When such amount is over 0.50 parts by
mass, fatty acid amide would bleed on the surface, and such bleeding would result in poor
appearance.
[0035]

In the present invention, fatty acid amide used as the component (D) (hereinafter
referred to as "fatty acid amide (D)") has a molecular weight of 298 or less. Any fatty acid
amide that can function as a lubricant can be used without particular limitation. Examples
thereof include unsaturated fatty acid amide, saturated fatty acid amide, substituted amide,
methylol amide, saturated bisamide, and unsaturated bisamide. A molecular weight of fatty
acid amide (D) is preferably 115 to 298, more preferably 199 to 298, and further preferably 280
to 298. When a molecular weight of fatty acid amide (D) is within the range described above,
the composition would be excellent in terms of bleeding on the surface of the formed product.
[0036]
Specific examples of fatty acid amide (D) include oleic acid amide (molecular weight:
282), stearic acid amide (molecular weight: 284), lauric acid amide (molecular weight: 199),
caproic acid amide (molecular weight: 115), and ricinoleic acid amide (molecular weight: 298),
with oleic acid amide and stearic acid amide being preferable.
[0037]
The amount of fatty acid amide (D) added is 0.01 to 0.50 parts by mass, preferably
0.10 to 0.50 parts by mass, and more preferably 0.10 to 0.30 parts by mass, relative to 100 parts
by mass of the total of the ethylene-based copolymer (A) and the propylene-based polymer (B).
When the amount of fatty acid amide (D) added is less than 0.01 parts by mass, the amount
thereof remaining on the resin surface is small at the time of molding, and it would not
contribute to achieve sufficient mold releasability. When such amount is over 0.50 parts by
9
mass, fatty acid amide would bleed on the surface, and such bleeding would result in poor
appearance.
[0038]
In the present invention, the amount of fatty acid amide (C) is designated Wc and the
amount of fatty acid amide (D) is designated Wd, and Wc/Wd is 0.5 to 1.5, and preferably 0.8
to 1.2. When Wc/Wd is less than 0.5, the effects of the lubricant may be lowered upon
sublimation because of a low molecular weight. When Wc/Wd is over 1.5, fatty acid amide
is less likely to appear on the surface because of a high molecular weight, and the effects of the
lubricant may be lowered.
[0039]

The composition according to the present invention may be supplemented with other
additives within a range not adversely affecting the effect of the present invention, in addition
to the ethylene-based copolymer (A), the propylene-based polymer (B), the fatty acid amide
(C) and the fatty acid amide (D). Additives are not particularly limited, and examples thereof
include known additives used in the polyolefin field, such as a softening agent, fillers, acid
acceptors, ultraviolet absorbers, antioxidants, heat stabilizers, light stabilizers, weathering
stabilizers, antistatic agents, and metal soap.
[0040]
It is preferable that the composition of the present invention be free of any crosslinked
rubber from the viewpoint of the mold releasability achieved by the components (C) and (D).
[0041]
In the composition of the present invention, the amounts of additives other than the
ethylene-based copolymer (A), the propylene-based polymer (B), the fatty acid amide (C), and
the fatty acid amide (D) added are not particularly limited, provided that the effects of the
present invention are exerted. The total amount of other additives are generally 5 parts by
mass or less, and preferably 0.5 to 3.0 parts by mass, relative to 100 parts by mass of the total
of the ethylene-based copolymer (A) and the propylene-based polymer (B).
[0042]

10
The composition of the present invention can be obtained by mixing at least the
ethylene-based copolymer (A), the propylene-based polymer (B), the fatty acid amide (C), and
the fatty acid amide (D) at a given ratio by, for example, a melt method or a solution method,
and preferably by a melt kneading method. A melt kneading method that is generally used for
thermoplastic resin can be adopted. The composition of the present invention can be prepared
by, for example, mixing powdery or granular components with other additives, according to
need, to obtain a homogeneous mixture with the use of a Henschel mixer, a ribbon blender, a
V-blender, or the like, and kneading the mixture with the use of single- or twin-screw extruder,
kneading rolls, a batch kneader, a kneader, a Banbury mixer, or the like. The components are
preferably subjected to melt kneading at 160°C to 260°C, and more preferably at 180°C to
230°C (e.g., temperature of a cylinder when an extruder is used). The order and the method
for kneading the components are not particularly limited.
[0043]
The formed product according to the present invention is obtained by molding the
composition of the present invention. The composition of the present invention can be
subjected to a known molding technique, such as injection molding, extrusion molding,
inflation molding, blow molding, extrusion blow molding, injection blow molding, press
molding, vacuum molding, calendar molding, or foam molding, to obtain various types of
formed products.
[0044]
Among the molding techniques described above, injection molding is particularly
preferable. In such a case, molding temperature is preferably 170°C to 260°C, and more
preferably 180°C to 250°C, from the viewpoint of flowability, mold transferability, and
oxidative degradation of resin components.
[0045]
It is particularly preferable that the formed product of the present invention be used
for automobile parts, such as automobile surface materials or automobile airbag cover materials.
[0046]
The present specification encompasses the content described in the specification of JP
2019-056712 which is the basis of priority of the present application.
11
Examples
[0047]
Hereafter, the present invention is described in greater detail with reference to the
examples, although the scope of the present invention is not limited to these examples.
[0048]
The methods of measurement of physical properties conducted in Examples and
Comparative Examples are as follows.
[0049]
[Melt flow rate: MFR]
The melt flow rate was measured at 230C or 190C under a load of 2.16 kg in
accordance with ISO1133.
[0050]
[Melting point (Tm)]
A melting point (Tm) is measured by differential scanning calorimetry (DSC) in the
manner described below. The sample (about 5 mg) is filled in an aluminum pan for exclusive
use. With the use of Diamond DSC (Perkin Elmer), the temperature is increased from 30°C
to 230°C at 500°C/min, maintained at 230°C for 10 minutes, decreased from 230°C to 30°C at
10°C/min, and maintained at 30°C for an additional 1 minute. A melting point is then
determined based on the endothermic curve obtained when temperature is increased at
10°C/min. When a plurality of peaks are detected via DSC, the temperature of the peak
detected at highest temperature is designated as the melting point (Tm).
[0051]
[Density]
Density was determined based on the weights of samples measured in water and in air
in accordance with ISO1183 (the immersion method).
[0052]
[Mold-release pressure]
At the time of molding using the injection molding apparatus descried below, a boxshaped
formed product (width: 140 mm; length: 140 mm; thickness: 2 mm) was ejected from
12
the mold, and the mold-release pressure at the time of ejection was measured using a pressure
sensor of the ejector pin.
[0053]
[Example 1 and Comparative Examples 1 to 3]
[Materials used]
(1) Ethylene-based copolymer (A)
As the ethylene-based copolymer (A), a commercially available pelletized ethylene-1-
butene copolymer (EBR-1) (granular; average particle diameter: 10 mm) having the physical
properties described below were used.
A constitutional unit derived from ethylene/(a constitutional unit derived from
ethylene + a constitutional unit derived from 1-butene) = 80 mol%
MFR (ISO1133, 230°C, load: 2.16 kg): 0.9 g/10 min
MFR (ISO1133, 190°C, load: 2.16 kg): 0.5 g/10 min
Melting point (Tm): not detected (measurement temperature: 30°C to 230°C)
Density: 861 kg/m3
[0054]
(2) Propylene-based polymer (B)
As the propylene-based polymer (B), a commercially available pelletized propyleneethylene
block copolymer (PP-1) (granular; average particle diameter: 10 mm) having the
physical properties described below were used.
Propylene content: 95 mol%
MFR (ISO1133, 230°C, load: 2.16 kg): 50 g/10 min
Melting point (Tm): 164°C
Density: 900 kg/m3
Tensile modulus of elasticity (ISO527): 1450 MPa
Charpy impact strength (ISO179, 23°C): 10 kJ/m2
Deflection temperature under load (ISO75, 1.8 MPa): 55°C
[0055]
(3) Fatty acid amide (C)
As the fatty acid amide (C), erucic acid amide (NOF Corporation) (melting point (Tm):
13
79°C to 84°C; molecular weight: 338) was used.
[0056]
(4) Fatty acid amide (D)
As the fatty acid amide (D), oleic acid amide (LION AKZO Co., Ltd.) (melting point
(Tm): 74°C to 76°C; molecular weight: 282) was used.
[0057]
Example 1
An ethylene-1-butene copolymer (EBR-1) (46 parts by mass) as the ethylene-based
copolymer (A), 54 parts by mass of a propylene-ethylene block copolymer (PP-1) as the
propylene-based polymer (B), 0.13 parts by mass of erucic acid amide as the fatty acid amide
(C), and 0.12 parts by mass of oleic acid amide as the fatty acid amide (D) were thoroughly
mixed using a Henschel mixer, and the mixture was subjected to extrusion kneading under the
conditions described below.
[0058]

Model: KTX-46, Kobe Steel Ltd.
Cylinder temperature: C1 and C2: 120°C; C3 and C4: 140°C; C5 to C14: 200°C
Die temperature: 200°C
Screw rotation speed: 400 rpm
Extrusion capacity: 80 kg/h
With the use of the polymer composition obtained, an injection-molded product (a test
piece) was produced using the injection molding apparatus described below, and a mold-release
pressure was measured. The results are shown in Table 1.
[0059]

Model: NEX140, Nissei Plastic Industrial Co., Ltd.
Cylinder temperature (injection molding temperature): 220°C
Mold temperature: 40°C
[0060]
Comparative Examples 1 to 3
14
The procedure of Example 1 was performed in the same manner except that the
amounts of the component (C) and the component (D) added were modified as shown in Table
1. The results are shown in Table 1.
[0061]
[Table 1]
Composition Unit Comp. Ex. 1 Comp. Ex. 2 Comp. Ex. 3 Ex. 1
Component (A):
EBR-1
Parts by mass 46 46 46 46
Component (B):
PP-1
Parts by mass 54 54 54 54
Component (C):
Fatty acid amide (C)
Parts by mass 0.25 0.35 0.13
Component (D):
Fatty acid amide (D)
Parts by mass 0.25 0.12
Mold-release pressure MPa 8 9 4 1
[0062]
As shown in Table 1, the present invention can provide an olefin-based polymer
composition that has achieved excellent mold releasability with the addition of a small amount
of a lubricant.
[0063]
The entire contents of all the publications, patents and patent applications cited in the
present specification are incorporated herein by reference.

WE CLAIMS

[1] A polymer composition comprising:
(A) 65 to 35 parts by mass of a copolymer containing a constitutional unit derived
from ethylene and a constitutional unit derived from an -olefin having 3 to 20 carbon atoms;
(B) 35 to 65 parts by mass of a propylene-based polymer having a melting point of
135°C to 170°C measured by DSC (provided that the total of the component (A) and the
component (B) is 100 parts by mass);
(C) 0.01 to 0.50 parts by mass of fatty acid amide with a molecular weight of 310 to
5,000 relative to 100 parts by mass of the total of the component (A) and the component (B);
and
(D) 0.01 to 0.50 parts by mass of fatty acid amide with a molecular weight of 298 or
less relative to 100 parts by mass of the total of the component (A) and the component (B),
wherein, when the amount of the component (C) is designated Wc and the amount of
the component (D) is designated Wd, Wc/Wd is 0.5 to 1.5, and the component (A) is not
crosslinked.
[2] The polymer composition according to Claim 1, wherein the amount of the component
(C) added and the amount of the component (D) added are each 0.10 to 0.50 parts by mass.
[3] The polymer composition according to Claim 1 or 2, wherein the component (C) and
the component (D) are each linear fatty acid amide.
[4] The polymer composition according to any one of Claims 1 to 3, wherein the
component (C) is erucic acid amide.
[5] The polymer composition according to any one of Claims 1 to 4, wherein the
component (D) is oleic acid amide.
[6] A formed product prepared from the polymer composition according to any one of
Claims 1 to 5.
[7] A method for producing an injection-molded product comprising subjecting the
polymer composition according to any one of Claims 1 to 5 to injection molding.