U.S. patent application number 11/779942 was filed with the patent office on 2008-02-28 for use of polyethylene glycol esters of fatty acids as lubricants for plastics.
Invention is credited to ERNST-UDO BRAND, PETER DAUTE.
Application Number | 20080051303 11/779942 |
Document ID | / |
Family ID | 37018617 |
Filed Date | 2008-02-28 |
United States Patent
Application |
20080051303 |
Kind Code |
A1 |
BRAND; ERNST-UDO ; et
al. |
February 28, 2008 |
USE OF POLYETHYLENE GLYCOL ESTERS OF FATTY ACIDS AS LUBRICANTS FOR
PLASTICS
Abstract
The invention relates to the use of polyethylene glycol esters
of fatty acids corresponding to the following formula:
R.sup.1--CO--O--(CH.sub.2--CH.sub.2--O).sub.n--OC--R.sup.2 (I) in
which R.sup.1 and R.sup.2 independently of one another represent
alkyl groups containing 7 to 23 carbon atoms, which may be
saturated or unsaturated, linear or branched, and n is a number of
2 to 50, as lubricants in the processing of thermoplastics.
Inventors: |
BRAND; ERNST-UDO;
(Bremerhaven, DE) ; DAUTE; PETER; (Beverstedt,
DE) |
Correspondence
Address: |
COGNIS CORPORATION;PATENT DEPARTMENT
300 BROOKSIDE AVENUE
AMBLER
PA
19002
US
|
Family ID: |
37018617 |
Appl. No.: |
11/779942 |
Filed: |
July 19, 2007 |
Current U.S.
Class: |
508/100 |
Current CPC
Class: |
C08K 5/103 20130101 |
Class at
Publication: |
508/100 |
International
Class: |
C10M 107/00 20060101
C10M107/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 20, 2006 |
EP |
06015123 |
Claims
1. A lubricated thermoplastic composition comprising: (a)
thermoplastic polymer; and (b) a polyethylene glycol difatty acid
ester lubricant of a formula:
R.sup.1--CO--O--(CH.sub.2--CH.sub.2--O).sub.n--OC--R.sup.2 (I) in
which R.sup.1 and R.sup.2 independently of one another represent
alkyl groups containing 7 to 23 carbon atoms, which may be
saturated or unsaturated, linear or branched, and n is a number of
2 to 50.
2. The lubricated thermoplastic composition of claim 1, wherein n
is a number of 2 to 4.
3. The lubricated thermoplastic composition of claim 1, wherein
R.sup.1 and R.sup.2 independently of one another are saturated
alkyl groups containing 7 to 23 carbon atoms.
4. The thermoplastic composition of claim 1, wherein the lubricant
is an internal lubricant.
5. The thermoplastic composition of claim 1, wherein, the lubricant
comprises a lubricant combination containing (a) at least one fatty
acid polyethylene glycol ester (I) and (b) at least one additional
lubricant (not covered by formula (I)), with the proviso that
components (a) and (b) are present in a ratio by weight of 10:90 to
90:10.
6. The lubricated thermoplastic of claim 5, wherein (a) and (b) are
present in a ratio by weight of 20:80 to 80:20.
7. The thermoplastic composition of claim 5, wherein, the lubricant
combination comprises an internal lubricant.
8. The lubricated thermoplastic of claim 1, wherein, the
thermoplastic comprises at least one member selected from the group
consisting of polycarbonates, polyamides, polyesters, polystyrenes,
polyvinyl chloride, and copolymers thereof.
9. A method of lubricating a thermoplastic which comprises: mixing
with the thermoplastic a polyethylene glycol difatty acid ester
lubricant of a formula:
R.sup.1--CO--O--(CH.sub.2CH.sub.2O).sub.n--OC--R.sup.2 (I) in which
R.sup.1 and R.sup.2 independently of one another represent alkyl
groups containing 7 to 23 carbon atoms, which may be saturated or
unsaturated, linear or branched, and n is a number of 2 to 50.
10. The method of claim 9, wherein, n is a member of from 2 to
4.
11. The method of claim 9, wherein, wherein R.sup.1 and R.sup.2
independently of one another are saturated alkyl groups containing
7 to 23 carbon atoms.
12. The method of claim 9, wherein, the lubricant is an internal
lubricant.
13. The method of claim 9, wherein, the lubricant comprises: a
lubricant combination containing (a) at least one fatty acid
polyethylene glycol ester (I) and (b) at least one additional
lubricant (not covered by formula (I)), with the proviso that
components (a) and (b) are present in a ratio by weight of 10:90 to
90:10.
14. The method of claim 13, wherein, (a) and (b) are present in a
ratio by weight of 20:80 to 80:20.
15. The method of claim 9, wherein, the thermoplastic comprises at
least one member selected from the group consisting of
polycarbonates, polyamides, polyesters, polystyrenes, polyvinyl
chloride, and copolymers thereof.
Description
RELATED APPLICATIONS
[0001] This application claims priority from EP 06015123.0 filed
Jul. 20, 2006, the entire contents of which have been incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to the use of polyethylene glycol
esters of fatty acids as lubricants for plastics.
BACKGROUND OF THE INVENTION
[0003] In the processing of thermoplastics, lubricants are added as
processing aids. On the one hand, the lubricants are capable of
reducing the internal friction between plastic particles which
makes the plastics easier to melt and promotes the formation of a
homogeneous, flowable melt. Lubricants acting in this way are also
commonly referred to as internal lubricants. On the other hand,
lubricants used in the processing of plastics are capable of
reducing the adhesion of the plastic melt to hot surfaces of
machine parts or to the walls of the molds. It is assumed that the
lubricants, which, after their incorporation in the plastic,
migrate from the plastic to the surface on account of their limited
compatibility, reduce adhesion. Lubricants acting in this way are
also known as external lubricants or as "mold release agents".
[0004] In principle, the use of the lubricants also has a
considerable bearing on the morphology, homogeneity and surface
qualities of the plastic products.
[0005] Whether an additive acts as internal or external lubricant
depends on many factors, more particularly on its structure and on
the nature of the plastic. In many cases, internal and external
lubricating effects may even be developed alongside one another.
Initial observations on lubricants in PVC and their effect as
internal and external lubricants can be found in the overview in
Gachter/Muller, Kunststoffadditive (2.sup.nd Edition, pp.
320-327).
[0006] Known lubricants for plastics include, for example, fatty
acids, fatty alcohols, fatty acid esters, fatty acid complex
esters, wax esters, dicarboxylic acid esters, amide waxes, metal
soaps, montan waxes, hydrocarbon waxes or oxidized
hydrocarbons.
[0007] Polyethylene glycol monoesters are used as antistatic and
antifogging agents in thermoplastics (cf. Antistatic PVC Materials,
Sheverdyaev, O.N. USSR, Plasticheskie Massy (1985), (4), 21-2;
ISSN: 0554-2901; in Russian; reported in CAPLUS: 1985:423262).
BRIEF DESCRIPTION OF THE INVENTION
[0008] The problem addressed by the present invention was to
provide lubricants, more especially internal lubricants, which
could be used in the processing of thermoplastics.
[0009] It has surprisingly been found that polyethylene glycol
esters of fatty acids can be used in excellent fashion as
lubricants and preferably as internal lubricants in the processing
of thermoplastics. The compounds are highly compatible with the
polymers and lead during processing to an improvement in the
plasticization of the polymer. Another advantage lies in the low
inherent volatility of the polyethylene glycol esters of fatty
acids.
[0010] The lubricants to be used in accordance with the invention
are characterized by the following formula:
R.sup.1--CO--O--(CH.sub.2--CH.sub.2--O).sub.n--OC--R.sup.2 (I) in
which R.sup.1 and R.sup.2 independently of one another represent
alkyl groups containing 7 to 23 carbon atoms, which may be
saturated or unsaturated, linear or branched, and n is a number of
2 to 50.
[0011] Accordingly, the present invention relates to the use of
polyethylene glycol esters of fatty acids corresponding to the
following formula:
R.sup.1--CO--O--(CH.sub.2--CH.sub.2--O).sub.n--OC--R.sup.2 (I) in
which R.sup.1 and R.sup.2 independently of one another represent
alkyl groups containing 7 to 23 carbon atoms, which may be
saturated or unsaturated, linear or branched, and n is a number of
2 to 50, as lubricants in the processing of thermoplastics. In a
preferred embodiment, n has a value of 2 to 4.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The term "lubricant" in the context of the present invention
denotes lubricants in the broader sense, i.e. external and/or
internal lubricants. If a narrower meaning is intended, it is
explicitly indicated (i.e. the expression "internal lubricant" is
expressly used).
[0013] The compounds (I) to be used in accordance with the
invention are preferably used in quantities of 0.05 to 5.0 parts by
weight, based on 100 parts by weight of the thermoplastic. The
range from 0.1 to 2.0 parts by weight is particularly
preferred.
[0014] Suitable C.sub.8-24 fatty acids are both native and
synthetic or branched and saturated or unsaturated compounds. The
fatty acids may be used in the form of mixtures. Examples of
suitable fatty acids are lauric acid, isotridecanoic acid, myristic
acid, palmitic acid, palmitoleic acid, stearic acid, isostearic
acid, oleic acid, elaidic acid, petroselic acid, linoleic acid,
linolenic acid, elaeostearic acid, arachic acid, gadoleic acid,
behenic acid and erucic acid. Fatty acids containing hydroxyl or
keto groups, such as 12-hydroxystearic acid, are also suitable.
[0015] Fatty acids such as these can be obtained from naturally
occurring fats and oils, for example by lipolysis at elevated
temperature and pressure and subsequent separation of the fatty
acid mixtures obtained, optionally followed by hydrogenation of the
double bonds present. Technical fatty acids are preferably used.
Technical fatty acids are generally mixtures of different fatty
acids of a certain chain length range with one fatty acid as the
main constituent. C.sub.12-18 fatty acids individually or in
admixture are preferably used.
[0016] Basically, there are no restrictions with regard to the
thermoplastics. Thermoplastics selected from the group consisting
of polycarbonates, polyamides, polyesters, polystyrenes and
polyvinyl chloride and copolymers thereof are preferred. These
thermoplastics may be stabilized, pigmented, filled with fillers or
modified.
[0017] In a preferred embodiment, the compounds (I) are used as
internal lubricants. All that has been said in the foregoing in
regard to the use of the compounds (I) as lubricants also applies
to their use as internal lubricants.
[0018] The compounds (I) to be used in accordance with the
invention--where they are used as lubricants or as internal
lubricants--may be used as such or in combination with other
typical lubricants different from the compounds (I) or other
additives for plastics.
[0019] Other typical lubricants are C.sub.12-24 fatty acids,
C.sub.12-24 fatty alcohols, esters of C.sub.12-24 fatty acids and
C.sub.12-24 fatty alcohols (so-called wax esters), esters of
C.sub.12-24 fatty acids and polyhydric alcohols containing 4 to 6
hydroxyl groups (so-called polyol esters), dicarboxylic acid esters
of dicarboxylic acids and C.sub.12-24 fatty alcohols and complex
esters of dicarboxylic acids, polyols and monocarboxylic acids. The
standard lubricants mentioned may be used both individually and in
admixture with one another.
[0020] The following observations apply to the optional other
lubricants different from the compounds of formula (I). [0021]
Suitable C.sub.12-24 fatty acids are both native and synthetic,
linear saturated compounds. If fatty acid mixtures are used, they
may contain unsaturated fatty acids. Examples of suitable fatty
acids are lauric, tridecanoic, myristic, pentadecanoic, palmitic,
margaric, stearic, behenic and lignoceric acid. Fatty acids
containing hydroxyl groups, such as 12-hydroxystearic acid, are
also suitable. Fatty acids such as these can be obtained from
naturally occurring fats and oils, for example through lipolysis at
elevated temperature and pressure and subsequent separation of the
fatty acid mixtures obtained, optionally followed by hydrogenation
of the double bonds present. Technical fatty acids are preferably
used here. They are generally mixtures of different fatty acids of
a certain chain length range with one fatty acid as the main
constituent. C.sub.12-18 fatty acids individually or in admixture
are preferably used. [0022] The C.sub.12-24 fatty alcohols are
mostly linear saturated representatives which may be obtained inter
alia from naturally occurring fats and oils by transesterification
with methanol, subsequent catalytic hydrogenation of the methyl
esters obtained and fractional distillation. Examples of such fatty
alcohols are lauryl, myristyl, cetyl, stearyl and behenyl alcohol.
These compounds may be used individually and in admixture with one
another. Technical fatty alcohols are preferably used. They are
normally mixtures of different fatty alcohols of a limited chain
length range in which one particular fatty alcohol is present as
the main constituent. Technical C.sub.12-18 fatty alcohol mixtures
are preferred. [0023] Other suitable additional lubricants are wax
esters, i.e. esters of C.sub.12-24 fatty acids and C.sub.12-24
fatty alcohols which preferably correspond to formula (II):
R.sup.3CO--OR.sup.4 (II) [0024] in which R.sup.3CO is a saturated
and/or unsaturated acyl group containing 12 to 24 and preferably 12
to 18 carbon atoms and R.sup.2 is an alkyl and/or alkenyl group
containing 12 to 24 and preferably 12 to 18 carbon atoms. Typical
examples are esters of lauric acid, isotridecanoic acid, myristic
acid, palmitic acid, palmitoleic acid, stearic acid, isostearic
acid, oleic acid, elaidic acid, petroselic acid, linoleic acid,
linolenic acid, elaeostearic acid, arachic acid, gadoleic acid,
behenic acid and erucic acid and technical mixtures thereof with
lauryl alcohol, isotridecyl alcohol, myristyl alcohol, cetyl
alcohol, palmitoleyl alcohol, stearyl alcohol, isostearyl alcohol,
oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, linoyl
alcohol, linolenyl alcohol, elaeostearyl alcohol, arachyl alcohol,
gadoleyl alcohol, behenyl alcohol, erucyl alcohol and brassidyl
alcohol and technical mixtures thereof. Preferred wax esters are
stearyl palmitate, stearyl stearate, stearyl isostearate, stearyl
oleate, stearyl behenate, stearyl erucate, isostearyl palmitate,
isostearyl stearate, isostearyl isostearate, isostearyl oleate,
isostearyl behenate, isostearyl erucate, oleyl palmitate, oleyl
stearate, oleyl isostearate, oleyl oleate, oleyl behenate, oleyl
erucate, behenyl palmitate, behenyl stearate, behenyl isostearate,
behenyl oleate, behenyl behenate, behenyl oleate and mixtures
thereof. Stearyl stearate is particularly preferred as the wax
ester. It is important in this regard to bear in mind that stearyl
stearate is normally produced from technical starting materials
which in turn are mixtures so that the ester is also a mixture.
[0025] The esters mentioned may be obtained by known methods of
organic synthesis, for example by heating stoichiometric quantities
of fatty acid and fatty alcohol to 180-250.degree. C., optionally
in the presence of a suitable esterification catalyst, such as tin
grindings, and in an inert gas atmosphere, and distilling off the
water of reaction. [0026] Suitable additional lubricants are polyol
fatty acid esters, i.e. esters of C.sub.12-24 fatty acids and
polyols containing 4 to 6 hydroxyl groups. The alcohol component
may be selected, above all, from aliphatic polyols containing 4 to
12 carbon atoms, for example erythritol, pentaerythritol,
dipentaerythritol, ditrimethylol propane, diglycerol, triglycerol,
tetraglycerol, mannitol and sorbitol. These polyol esters may be
full esters in which all the hydroxyl groups of the polyol are
esterified with fatty acid. However, polyol partial esters
containing one or more free hydroxyl groups in the molecule are
also suitable. These polyol fatty acid esters may also be obtained
by known methods of organic synthesis by esterification of the
polyols with stoichiometric or sub-stoichiometric quantities of
free fatty acids. Examples of such polyol fatty acid esters are the
stearic acid and stearic acid/palmitic acid full esters of
erythritol, pentaerythritol and diglycerol, the dilaurates of
dipentaerythritol, ditrimethylolpropane, triglycerol, mannitol and
sorbitol, the distearates of erythritol, pentaerythritol,
dipentaerythritol and tetraglycerol and the so-called sesquiesters
of pentaerythritol, dipentaerythritol, mannitol and sorbitol in
whose production 1.5 mol fatty acid, more particularly palmitic
and/or stearic acid, is used to 1 mol polyol. The polyol fatty acid
esters mentioned are generally mixtures simply because of the
particular starting materials used. [0027] Other suitable
additional lubricants are complex esters which are also known per
se from the prior art. In principle, the complex esters are
produced from dicarboxylic acids, polyols and monocarboxylic acids.
The following dicarboxylic acids may be used for the production of
the complex esters: oxalic, malonic, succinic, glutaric, adipic,
pimelic, suberic, azelaic, sebacic, nonanedicarboxylic,
undecanedicarboxylic, eicosanedicarboxylic, maleic, fumaric,
citraconic, mesaconic, itaconic, cyclopropanedicarboxylic,
cyclobutanedicarboxylic, cyclopentanedicarboxylic, camphor,
hexahydrophthalic, phthalic, terephthalic, isophthalic, naphthalic
and diphenyl-o,o'-dicarboxylic acid. The following compounds are
generally used as aliphatic polyols containing 2 to 6 hydroxyl
groups: ethylene glycol, 1,2-propylene glycol, 1,3-propylene
glycol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol,
1,6-hexanediol, glycerol, trimethylolpropane, erythritol,
pentaerythritol, dipentaerythritol, xylitol, mannitol and sorbitol.
Suitable monocarboxylic acids are linear or branched, synthetic or
native acids, for example lauric, myristic, palmitic, margaric,
stearic, arachic, behenic, lignoceric, cerotic acid, montanic acid,
oleic, elaidic, erucic, linoleic, linolenic and isostearic acid and
mixtures of these acids, particularly those obtainable from natural
fats and oils. Preferred complex esters are produced from aliphatic
dicarboxylic acids containing 4 to 8 carbon atoms, polyols
containing 3 or 4 hydroxyl groups and aliphatic monocarboxylic
acids containing 14 to 22 carbon atoms. Excellent results are
obtained with complex esters of adipic acid, pentaerythritol and
monocarboxylic acids containing 14 to 22 carbon atoms. [0028]
According to the invention, other suitable additional lubricants
are dicarboxylic acid esters of fatty alcohols containing 12 to 24
carbon atoms. Suitable dicarboxylic acids have already been
mentioned by way of example in connection with the complex esters.
Suitable fatty acids are the fatty acids already discussed above.
Phthalic acid esters, more especially distearyl phthalate, are
particularly preferred. [0029] Other additional lubricants, which
may be used individually or in combination, are hydrocarbon waxes
melting at temperatures in the range from 70 to 130.degree. C.,
oxidized polyethylene waxes, .alpha.-olefins, ethylenediamine
distearate, montanic acid esters of diols, for example ethanediol,
1,3-butanediol and glycerol, mixtures of such montanic acid esters
with unesterified montanic acids and metal soaps, more particularly
salts of organic monocarboxylic acids with metals of the second
main and/or secondary group of the periodic system, such as calcium
soaps and zinc soaps.
[0030] Accordingly, the present invention also relates to the use
of lubricant combinations for thermoplastics containing [0031] (a)
one or more fatty acid polyethylene glycol esters (I) and [0032]
(b) one or more additional lubricants (not covered by formula (I)),
with the proviso that components (a) and (b) are used in a ratio by
weight of 10:90 to 90:10 and preferably in a ratio by weight of
20:80 to 80:20.
[0033] The expression "lubricant combinations" applies both to
lubricants and to internal lubricants.
[0034] In practice, the lubricant mixtures according to the
invention are applied by addition to the thermoplastics to be
processed in quantities of 0.05 to 5 and more particularly 0.1 to 2
parts by weight to 100 parts by weight of thermoplastic. The
lubricant mixtures are preferably added to the melt formed during
production of the thermoplastic or are applied to the plastic
granules or powder at elevated temperatures.
[0035] The thermoplastics may optionally contain additional
additives. Examples of suitable additives are antistatic agents,
antifogging agents, antioxidants, UV stabilizers, coupling agents,
calendering aids, parting agents, lubricants, plasticizers,
perfumes, flame retardants, fillers and agents for increasing heat
stability (heat stabilizers).
[0036] The thermoplastics may readily be further processed by
standard methods, for example by extrusion, pressing, rolling,
calendering, sintering, spinning, blow moulding, foaming, injection
moulding or processing by the plastisol method.
EXAMPLES
1. Production of the Lubricants According to the Invention
Example 1
[0037] 237 g diethylene glycol (Fluka), 1151 g technical stearic
acid (Cognis) and 0.7 g tin(II) oxalate (Goldschmidt) were heated
under nitrogen. The esterification reaction began at ca.
170.degree. C. with the formation of water. After 3 hours, removal
of the water of reaction was continued by application of vacuum,
the vacuum being lowered to ca. 15 mbar over a period of 4 hours.
The final temperature was 200.degree. C.
[0038] The reaction was terminated at an acid value (AV) of <6.
The reaction mixture was cooled to 90.degree. C. and filtered.
Yield 1296 g, AV=1.6, SV (saponification value)=184.
Example 2
[0039] PEG-600 distearate was produced from 167 g PEG 600 (Fluka)
and 147 g technical stearic acid (Cognis) in the same way as in
Example 1. Yield 298 g, AV=5.9, SV=102.
2. Production of Dry Blends
[0040] Using a Henschel mixer, a dry blend was produced from PVC
powder and various additives (quantity of material=3 kg, heating
temperature=120.degree. C., subsequent cooling). The compositions
are set out in the following Table (the numbers in the Table
represent parts by weight). TABLE-US-00001 Example C1 C2 C3 E3 E4
PVC Evipol SH 6520 (Ineos) 100 100 100 100 100 Pb sulfate, tribasic
2 2 2 2 2 Lead stearate (28% Pb) 0.5 0.5 0.5 0.5 0.5 Calcium
stearate 0.5 0.5 0.5 0.5 0.5 Hydrogenated castor oil -- 1.0 -- --
-- Distearyl phthalate -- -- 1.0 -- -- Lubricant of Example 1 -- --
1.0 -- Lubricant of Example 2 -- -- -- 1.0
[0041] In this Table, C1 to C3 are comparison Examples. In C1, no
lubricant was added. In C2, hydrogenated castor oil was used; it is
the most important internal lubricant for PVC bottles (cf. Plastics
Additives Handbook, 5.sup.th Edition, Hanser Verlag, p. 537). In
C3, distearyl phthalate--an internal lubricant for profile
extrusion--was used. E4 and E5 represent formulations according to
the invention.
3. Production of Ribbons
[0042] The above-mentioned dry blends were extruded to ribbons in a
Weber twin-screw extruder (extrusion parameters: screw speed=15
r.p.m.: temperature=190.degree. C.). The power consumed by the
extruder, the machine load (in %), was evaluated as a measure of
plasticization. Early plasticization leads to an increase in the
machine load. The melt pressure (bar) before the die was used as a
measure of lubricant performance. A low melt pressure signifies a
good lubricating effect. TABLE-US-00002 Example Machine load (%)
Melt pressure (bar) C1 48.7 347 C2 56.6 354 C3 46.0 324 E4 51.1 344
E5 57.8 336
[0043] Examples E4 and E5 according to the invention led to earlier
plasticization (increase in machine load) at a relatively low melt
pressure than Comparison Example C1. Comparison Examples C2 and C3
lead either to better plasticization for an increase in melt
pressure or impair plasticization.
* * * * *