Title of Invention

"POLOYOXYMETHYLENE COMPOSITION HAVING HIGH FUEL RESISTANCE"

Abstract Disclosed is a polyoxymethylene composition having high fuel resistance, which includes a polyoxymethylene polymer, magnesium stearate, and an antioxidant. Also, a shaped article produced from the polyoxymethylene composition is provided, which is suitable for use in fuel feeding and circulation systems'of automobiles.
Full Text POLYOXXMETHYLENE COMPOSITION HAVING HIGH FUEL RESISTANCE
AND SHAPED ARTICLE PRODUCED THEREFROM
Technical Field
The present invention relates, generally, to a
polyoxymethylene composition having high fuel resistance, and a
shaped article produced therefrom, which is suitable for use in
fuel feeding and circulation systems of automobiles. More
specifically, the present invention relates to a
polyoxymethylene composition having high fuel resistance, which
includes magnesium stearate.
Background Art
As global automotive markets have continuously pursued
lightweight and monolithic structures, metal materials used for
fuel-related components of automobiles have been replaced by
plastics. Further, properties required for such plastics
gradually become stringent.
The fuel-related components of automobiles are coinposed
of polyoxymethylene (hereinafter, abbreviated as 'POM'},
polyamide 6, polyamide 12, polybutylene tereph thai ate,
polyphenylene sulfide, high density polyethylene, etc.,
depending on operation conditions thereof.
POM, which is a crystalline resin, has high mechanical
properties, creep resistance, fatigue resistance, wear
resistance and chemical resistance, and thus, is widely applied
to components requiring complex properties, such as various
electric and electronic products, automotive components and
other mechanical mechanisms.
In particular, the amount of PCM used in automobiles
increases in accordance with the development of automotive
industries, in which the POM is increasingly used in fuel
systems.
Typically, the fuel system of a gasoline-powered
automobile which includes POM is operated at a maximum of 65°C,
which is an operation temperature suitable for the POM.
However, in the case of an automobile with a diesel
engine developed recently, a fuel-related component is operated
at a maximum of 100-120°C, which is drastically increased in
comparison with conventional temperatures. Thus, the
automotive components made of POM should be able to meet the
above requirements. Further, diesel fuel is known to age at a
high temperature, which causes decomposition of POM.
In addition, a sulfur compound present in the diesel fuel
is oxidized when being exposed to air, to produce an acidic
sulfur compound, which acts to cause the decomposition of POM.
Also, oxides, acting to cause the decomposition of POM,
are formed even in aggressive gasoline fuel, thus remarkably
decreasing the durability of the fuel system.
Therefore, a material used for an automotive component in
direct contact with fuel should have high mechanical properties
and fuel resistance.
In this regard, U.S. Patent No. 6,489,388 discloses a
thermoplastic molding composition including zinc oxide and
polyethylene glycol as a fuel resistant composition comprising
POM. However, since the fuel resistant (diesel resistant)
composition including zinc oxide and polyethylene glyccl
retains only about 40-50% of tensile elongation, an improvement
of the above composition ro fuel resistance is not large.
To fulfill more stringent requirements of automotive
manufacturers, a POM composition having further improved fuel
resistance is needed.
Disclosure of the Invention
Accordingly, the present invention has been made keeping
in mind the above problems occurring in the related art, and an
object of the present invention is to provide a POM composition
having high resistance to aggressive gasoline fuel and diesel
fuel having a large content of sulfur compounds.
t is another object of the present invention to provide
a shaped article produced from the POM composition, which, is
suitable for use in fuel feeding and circulation systems of
automobiles requiring high fuel resistance.
The above objects are accomplished by a provision of a
POM composition having high fuel resistance, which comprises
100 parts by weight of polyoxymethylene polymer (A); 0.1-2.0
parts by weight of magnesium stearate (B) ; and 0.01-1.0 parts
by weight of an antioxidant (C) .
In addition, the POM composition further comprises 0.01-
2.0 parts by weight of a thermal stabilizer (D) . As well, the
POM composition, which comprises the components (A) , (B) and
(C), or the components (A), {3} , (C) and (D), further cccrprises
50 parts by weight or less of a reinforcing agent (E) .
Further, the present invention provides a shaped article
produced from the above POM composition, which is suitable for
use in fuel feeding and circulation systems of automobiles
requiring high fuel resistance.
Best Mode for Carrying Out the Invention
Hereinafter, a detailed description will be given of the
present invention.
According to the present invention, a POM resin
composition (hereinafter, referred to as APOM composition' ) ,
obtained by adding magnesium stearate as an inorganic antacid
to a POM. resin, has high fuel resistance.
That is, the POM composition of the present invention
manifests fuel resistance of high tensile strength and tensile
elongation without causing the decomposition of POM even in the
presence of aggressive gasoline and hot diesel having a larger
content of sulfur compounds. Aggressive gasoline fuel means
gasoline including various compounds able to cause the
decomposition of POM.
Used as a main ingredient in the POM composition having
fuel resistance of the present invention, a POM polymer (A) ray
be any of a homopolymer of an oxymethylene group represented by
Formula 1, below, or a copolymer resulting from a random
copolymerization of a monomeric group of Formula 1 and a
monomeric group represented by Formula 2, below. The POM
polymer (A) preferably has a molecular weight in a range from
10,000 to 200,000 g/mol:
Wherein Xi and X2, which are the same or different,
each hydrogen, an alkyl group or an aryl group, and x is an
integer of 2 to 6.
The oxymethylene homopolymer is produced by
polymerization of formaldehyde or a cyclic oligomer thereof,
that is, trioxane. Also, the oxymethylene copolyrner, which
results from the random copolymerization of the monomeric group
of Formula 1 and the monomeric group of Formula 2, is obtained
by randomly copolyrnerizing formaldehyde or the cyclic oligomer
thereof and cyclic ether represented by Formula 3 or cyclic
formal represented by Formula 4:
Formula 3
Formula 4
Wherein Xs, X4, Xs and Xe, which are the same or different,
are each hydrogen or an alkyl group and may be linked to
same carbon atom or different carbon atoms, and n and m are each
an integer from 2 to 6.
As the comonomer used for the random copolymerizatipn,
cyclic ether includes, for example, ethyleneoxide,
propyleneoxide, butyler.eoxide, phenyleneoxide, etc., and cyclic
formal includes, for example, 1,3-dioxolane,
diethyleneglycolformal, 1,3-propanediolformal, 1,4-
butanediolformal, 1,3-dioxepanformal, 1, 3,6-trioxocane, etc.
Preferably, the comonomer selected from among
ethyleneoxide, 1,3-dioxolane, 1,4-butanediolformal, and
combinations thereof is used. The above comonomer is added to
trioxane or formaldehyde as a nain comonomer, and then randonly
ccpclymerized in the presence cf a Lewis acid catalyst, thereby
producing an oxymethyiene copolymer having a melting point of
150°C or higher with at least two adjacent carbon atoms in the
main chain.
In the oxymethyiene copolymer, a molar ratio of
oxymethyiene molecular structure to oxymethyiene repeat unit is
in the range of 0.05 to 50, and preferably, 0.1 to 20.
The catalyst used in polymerization to obtain the
oxymethyiene polymer includes an anionic catalyst or a cat ionic
catalyst, which are known in the art. The catalyst for
polymerization of trioxane is exemplified by halogens, such as
chlorine, bromine, and iodine; organic and inorganic acids, such
as alkyl- or allyl-sulfonic acid, HC104, HI04, HC104 derivatives,
CPh3C(I04), and R3SiHS04; metal halogen compounds, such as BF3,
SbF3, SnCl4, TiCl4, FeCl3, ZrCl4, MoCl5, and SiF4; complexes of
metal halogen compounds, such as BF3 • OH2, BF3 • OEt2, BF3 -OBu2,
BF3 • CH3COOH, BF3 • PF5 • HF, BF3-10-hydroxyacetophenol, Ph3CSnCl5,
Ph3CBF4, and Ph3CSbCle; metal ester, such as carbcxylate
compounds of copper, zinc, cadmium, iron, cobalt, and nickel;
metal oxides, such as PaOg + sCb, and P20s+phosphate ester; and
combinations of organic metal and metal halogen compounds. Of
the above catalysts, it is preferable that a coordinated
compound of boron trifluoride be used. More preferably,
BF3 • OEt2 and BF3 • OBu2 are used. The catalyst used for
polymerization is used in the racl range from 2 xic~ tc 2 xic~2
based on 1 mol of trioxane.
The polymerization may be carried out in a manner of bulk
polymerization, suspension polymerization or solution
polymerization, at 0-100°C, and preferably, 20-80°C.
On the other hand, an inactivator for inactivating unused
catalyst remaining after the polymerization reaction includes,
for example, tertiary amines, such as triethylamine, cyclic
sulfur compounds, such as thiophene, and phosphorus compounds,
such as triphenylphosphine, all of which are Lewis bases having
unshared electron pairs and form a complex salt together with
the catalyst.
Further, upon production of polyoxymethylene, a chain
transferring agent, which is exemplified by alkyl-substituted
phenols or ethers, may be used. In particular, alkylether, such
as dimethoxymethane, is preferable.
To increase fuel resistance, magnesium stearate (B) as an
inorganic antacid is used in an amount of 0.1-2.0 parts by
weight, and preferably, 0.5-2.0 parts by weight, based on 100
parts by weight of the POM polymer. If magnesium stearate is
added in an amount less than 0.1 parts by weight, there is no
improvement to fuel resistance. Meanwhile, if magnesium
stearate is added in an amount exceeding 2.0 parts by weight,
the properties and thermal stability of the POM composition
decrease undesirably.
An antioxidant (C) used in the present invention includes
hindered phenols, for example, 2,2'-methylenebis (4-methyl-6-tbutylphenol),
hexamethyleneglycol-bis-(3,5-di-t-butyl-4-
hydroxyhydrocinnamate), tetrakis [methylene(3,5-di-t-butyl-4-
hydroxyhydrocinnamate)]methane, triethyleneglycol-bis-3-(3-tbutyl-
4-hydroxy-5-methylphenyl) propionate, 1,3,5-trimethyl-
2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, n-octadecyl-
3- (4' -hydroxy-3', 5' -di-t-butylphenol) propionate, 1,6-hexanediol-
bis-3 (3,5-di-t-butyl-4-hydroxy-phenyl)propionate, 4,4'-
methylenebis(2,6-di-t-butylphenol), 4,4'-butylidene-bis-(6-tbut
yl-3-methyl-phenol), di-stearyl 3,5-di-t-butyl-4-
hydroxybenzylphosphate, 2-t-butyl-6- (3-t-butyl-5-methyl-2-
hydroxybenzyl) -4-methylphenylacrylate, 3, 9-bis2- [3- (3-t-butyl-4-
hydroxy-5-methylphenyl) propionyloxy] -I, l-dimethylethyl-2,4,8,10-
tetraoxaspiro[5,5]undecane, etc.; or hindered amines, for
example, 4-acetcxy-2, 2, 6, 6-tetramethylpiperidine, 4-stearcyloxy-
2,2,6, 6-tetramethylpiperidine, 4-acryloyloxy-2,2, 6, 6-
tetramethylpiperidine, 4-methoxy-2, 2,6, 6-tetramethylpiperidine,
4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclchexyloxy-
2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6, 6-
tetramethylpiperidine, 4-benzyloxy-2,2, 6, 6-
tetramethyipiperidine, 4- (phenylcarbamoyioxy) -2,2, 6, 6-
tetramethylpiperidine, bis (2,2,6, 6-tetramethyl-4-i
piperidyl; oxaiate, bis (2,2, c, 6-tetxamethyl-4-piperidyl; =lonate,
bis(2,2,6, 6-tetramethyl-4-piperidyl)adipate, bis(2,2, 6, 6-
tetramethyl-4-piperidyl) sepacate, bis (1,2,2,6, 6-pentamethylpiperidyl)
sepacate, bis (2,2,6, 6-tetramethyl-4-
piperidyl) terephthalate, 1,2-bis (2,2,6, 6-tetramethyl-
piperidyloxy) ethane, bis (2,2,6, 6-tetramethyl-4-
piperidyl) hexamethylene-1,6-dicarbamate, bis (l-methyl-2,2, 6,6-
tetramethyl-4-piperidyl) adipate, tris (2,2,6, 6-tetramethyl-4-
piperidyl)benzene-l,3,5-tricarboxylate, etc. Of them,
triethyleneglycol-bis-3- (3-t-butyl-4-hydroxy-5-methylphenyl) -
propionate, 1,6-hexane-diol-bis-3 (3,5-di-t-butyl-4-hydroxyphenyl)
propionate, or tetrakis [methylene (3,5-di-t-butyl-4-
hydroxyhydrocinnamate)] methane is preferably used. More
preferably/ triethyleneglycol-bis-3- (3-t-butyl-4-hydroxy-5-
methylphenyl) -propionate is used.
The antioxidant is used in an amount of 0.01-1.0 parts by
weight, and preferably, O.i-0.5 parrs by weight, based on 100
parts by weight of the POM polymer. If the antioxidant is used
in an amount less than 0.01 parts by weight, thermal stability
of POM becomes poor. Contrarily, if the antioxidant is used in
an amount exceeding 1.0 part by weight, the effects of the
antioxidant are not further increased.
In addition, a thermal stabilizer (D) used in the present
invention is exemplified by nitrogen-containing compounds which
function to increase the thermal stability of the POM polymer by
reaction with formaldehyde, for example, 6-phenyl-i,3,5-
triazine-2, 4-triamine (benzoguanamine) , 2,4, 6-triamino-l, 3, 5-
triazine (melamine), carbonyldiamide (urea), dicyandiamide,
isophthalic dihydrazide (hydrazine), or alcohols, for example,
polyethyleneglycol, ethylene-vinylalcohol copolymer, sorbitol,
sorbitan, etc. In particular, 2,4,6-triamino-l, 3,5-triazine
(melamine) is preferably used. The thermal stabilizer is used
in an amount of 0.01-2.0 parts by weight, and preferably, 0.1-
1.0 parts by weight, based on 100 parts by weight of the POM
polymer. When the thermal stabilizer is used in an amount
exceeding 2.0 parts by weight, the properties of final shaped
articles are deteriorated.
Further, a reinforcing agent (E) which is selected from
among glass fiber, carbon fiber, whisker, carbon black,
graphite, molybdenum disulfide, calcium carbonate, talcum, and
combinations thereof, if necessary, is used in an amount of 50
parts by weight or less, based on 100 parts by weight of the POM
composition.
Thus, even if the POM composition containing magnesium
stearate of the present invention is in contact with fuel for a
long period, it has stable mechanical properties, weight and
dimensions, and as well, is highly producible. Thereby, the POM
composition of the present invention can be usefully applied to
manufacture automotive components requiring fuel resistance.
A better understanding of the present invention may be
obtained through the following examples and comparative
examples which are set forth to illustrate, but are not to be
construed as the limit of the present invention.
EXAMPLES 1-2 AND COMPARATIVE EXAMPLES 1-6
In the present examples and comparative examples,
variation of properties of a POM composition with the kind of
inorganic antacid was assayed.
1. Preparation of POM composition
KEPITAL F25-03H (Korea Engineering Plastics Co. Ltd.)'as
a POM, 0.2 phr of 1010 (songnox, tetrakis [methylene(3,5-di-tbutyl-
4-hydroxyhydrocinnamate) ]methane, Songwon Industrial Co.
Ltd., Korea) as an antioxidant, 0.1 phr of melamine (Samsung
Fine Chemicals Co. Ltd., Korea) as a thermal stabilizer, and
1.0 phr cf each inorganic antacid shown in Table- 1, below, were
mixed and extruded at 170-230°C, to pellet POM compositions.
Each POM composition was injection molded at 170-210°C, to
manufacture test samples, which were shown as POM compositions
of Example 1 and Comparative Examples 1-6 in Table 2, below.
In addition, a test sample of POM composition without a thermal
stabilizer was prepared and shown as a POM composition of
Tensile strength, tensile elongation, weight change, and
dimension change of the test samples of Examples 1-2 and
Comparative Examples 1-6 were measured to determine the fuel
resistance of each POM composition. The results are given in
Table 2, below.
Each test sample was immersed in diesel fuel (containing
lwt% sulfur) at 100°C for 0, 500 and 1000 hrs using a container
able to withstand high temperature and high pressure. Then,
tensile strength, tensile elongation, weight change and
dimension change of the samples were measured in accordance
with the following procedures.
(Tensile Strength and Tensile Elongation)
Tensile strength and tensile elongation were measured at
a tesr speed of 5 mm/min and a gauge length of 115 ~. using a
UTM (Universal Testing Machine).
(Weight Change)
After the surface of the test sample removed from the
diesel fuel was wiped clean, the test sample was weighed within
5 min using a chemical balance.
(Dimension change)
After the surface of the test sample removed from the
diesel fuel was wiped clean, the dimension of the test sample
(Table Removed)
As is apparent from Table 2, it can be shown that the
retention of tensile strength and tensile elongation differs in
accordance with the kind of inorganic antacid, and the PCM
composition has high fuel resistance (diesel resistance) when
it comprises magnesium stearate.
A PCM composition was prepared in the same manner as in
Example 1, with the exception of further including 25 parts by
weight of glass fiber as a reinforcing agent, after which the
properties of the POM composition were measured. The results
are given in Table 3, below.
Comparative Example 7
A POM composition was prepared in the same manner as in
Comparative Example 1, with the exception of further including
25 parts by weight of glass fiber as a reinforcing agent, after
which the properties of the POM composition were measured. The
results are given in (Table Removed)









We claim: -
1. A polyoxymethylene composition having high fuel resistance, comprising:
100 parts by weight of polyoxymethylene polymer (A);
0.1-2.0 parts by weight of magnesium stearate (B); and 0.01-1.0 parts by weight of an antioxidant (C).
2. The polyoxymethylene composition as claimed in claim 1, comprising 0.01-2.0 parts by weight of a thermal stabilizer (D).
3. The polyoxymethylene composition as claimed in claim 1 or 2, comprising 50 parts by weight or less of a reinforcing agent (E).
4. A polyoxymethylene composition substantially as herein described with reference to the
foregoing description, examples, formulas and the accompanying tables.

Documents:

4107-DELNP-2006-Abstract 03-11-2011.pdf

4107-DELNP-2006-Abstract-(04-11-2011).pdf

4107-DELNP-2006-Abstract-(09-08-2010).pdf

4107-delnp-2006-abstract.pdf

4107-DELNP-2006-Assignment-(09-08-2010).pdf

4107-delnp-2006-assignments.pdf

4107-DELNP-2006-Claims-(09-08-2010).pdf

4107-DELNP-2006-Claims-(12-08-2010).pdf

4107-delnp-2006-claims.pdf

4107-DELNP-2006-Correspondence Others-(04-11-2011).pdf

4107-DELNP-2006-Correspondence-Others-(09-08-2010).pdf

4107-DELNP-2006-Correspondence-Others-(12-08-2010).pdf

4107-DELNP-2006-Correspondence-Others-(20-09-2010).pdf

4107-delnp-2006-Correspondence-Others-(22-12-2009).pdf

4107-delnp-2006-correspondence-others-1.pdf

4107-delnp-2006-correspondence-others.pdf

4107-delnp-2006-description (complete).pdf

4107-DELNP-2006-Form 1-03-11-2011.pdf

4107-DELNP-2006-Form 2-03-11-2011.pdf

4107-DELNP-2006-Form-1-(04-11-2011).pdf

4107-delnp-2006-form-1.pdf

4107-DELNP-2006-Form-13-(12-08-2010).pdf

4107-delnp-2006-form-18.pdf

4107-DELNP-2006-Form-2-(04-11-2011).pdf

4107-delnp-2006-form-2.pdf

4107-DELNP-2006-Form-3-(09-08-2010).pdf

4107-delnp-2006-Form-3-(22-12-2009).pdf

4107-delnp-2006-form-3.pdf

4107-DELNP-2006-Form-5-(09-08-2010).pdf

4107-delnp-2006-form-5.pdf

4107-DELNP-2006-GPA-(09-08-2010).pdf

4107-delnp-2006-pct-101.pdf

4107-delnp-2006-pct-210.pdf

4107-delnp-2006-pct-402.pdf

4107-delnp-2006-pct-409.pdf

4107-delnp-2006-pct-416.pdf

4107-delnp-2006-pct-notification.pdf

4107-DELNP-2006-Petition 137-(20-09-2010).pdf


Patent Number 249725
Indian Patent Application Number 4107/DELNP/2006
PG Journal Number 45/2011
Publication Date 11-Nov-2011
Grant Date 04-Nov-2011
Date of Filing 17-Jul-2006
Name of Patentee KOREA ENGINEERING PLASTICS CO., LTD.
Applicant Address 450 GONGDUK-2 DONG, MAPO-GU, SEOUL 121-805, REPUBLIC OF KOREA
Inventors:
# Inventor's Name Inventor's Address
1 SHIN KI-CHUL 403-603 HANLA APT. 1156-1 OGEUM-DONG, GUNPO, KYUNGKI-DO 435-857, REPUBLIC OF KOREA
2 KIM, TAK-KYU 982-2205 BAEKDOO APT., GOONGNAE-DONG, GUNPO, KYUNGKI-DO 435-047, REPUBLIC OF KOREA
3 JEONG CHUNG-RYOL 205-1202 HANGARAM APT. 1586-5 GWANYANG-DONG, DONGAN-GU, ANYANG, KYUNGKI DO 431-060, REPUBLIC OF KOREA.
PCT International Classification Number C08L 59/00
PCT International Application Number PCT/KR2004/003333
PCT International Filing date 2004-12-17
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10-2003-0094542 2003-12-22 Republic of Korea