Note: Descriptions are shown in the official language in which they were submitted.
CA 022l~67~ l997-09-l6
H 1688 PCT
14.02.1996
A plastisol composition
This invention relates to plastisol compositions
contalning monoesters of fatty acids bearing at least
12 carbon atoms, to a process for their production and
to their use.
Plastisols are generally dispersions of organic
polymers in plasticizers which gel on heating to rela-
tively high temperatures and cure on cooling to form
the plastigel. Today, the most widely used plastisols
in practice by far predominantly contain finely
powdered polyvinyl chloride, copolymers of vinyl
chloride and, more recently, methacrylate copolymers or
styrene copolymers. These finely powdered polymers are
dispersed in a liquid plasticizer and form the paste-
like plastisol. Corresponding plastisols are used for
various applications. They are used, for example, as
sealing compounds, for impregnating and coating
substrates of textile materials, as cable insulations
and as adhesives. In the automotive industry,
plastisols are used for underbody protection, for
sealing seams, for lining hoods, as vibration-damping
materials or as adhesives. Depending on the particular
application envisaged, the plastisols contain other
additives in addition to the fine-particle polymer
powders and the liquid plasticizers. These other
additives include, for example, fillers, coupling
agents, stabilizers, flow aids, water-absorbing
substances, pigments or blowing agents.
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H 1688 PCT 2
The plasticizers used, or suitable for use, in
plastisol technology may be classified according to
various aspects, the clearest classification being
based on the chemical product classes of the
plasticizers, such as phthalates, epoxides, aliphatic
dicarboxylic acid esters, phosphates, polyesters,
special plasticizers, extenders (hydrocarbons,
chlorinated hydrocarbons). Most industrially used
plasticizers are chemically stable diesters and
triesters of aromatic or aliphatic di- and
tricarboxylic acids. In a few cases, non-ester-like
compounds with a plasticizing effect are also used.
Phthalic acid diesters are by far the most widely used,
especially for PVC homopolymers and copolymers, because
hitherto they have been inexpensively available in
large quantities. According to H.K. Felger (Editor),
Kunststoffhandbuch "Polyvinylchlorid", Vol. 2/1, 2nd
Edition 1985, Chapter 6.7, the particularly inexpensive
dioctyl phthalates (di-2-ethylhexyl phthalate or
diisooctyl phthalate) have hitherto enjoyed a dominant
market share. However, because they may possibly be
harmful to health, considerable efforts are being made
worldwide to replace them by other plasticizers. Other
common phthalate plasticizers are the various isomeric
diisononyl phthalates, diisodecyl phthalates and
diundecyl phthalates. The phthalic acid esters of
C8/C10 alcohols or C7/C11 alcohols are also frequently
used. However, these plasticizers have become
considerably more expensive than the dioctyl
phthalates, especially in recent years. Although the
CA 022l~67~ l997-09-l6
H 1688 PCT 3
aliphatic dicarboxylic acid esters, especially the
diadipates, diazelates and disebacates, have excellent
low-temperature properties, they are only used in
special cases on account of their high price. The same
applies to the phosphate plasticizers, to the polyester
plasticizers and to the other special plasticizers such
as, for example, esters of terephthalic acid,
trimellitic acid, pyromellitic acid, citric acid and
the alkyl sulfonic acid esters of phenol and cresol.
To reduce costs, the hitherto known extenders or
secondary plasticizers, largely hydrocarbons, are only
used in admixture with primary plasticizers. Unfortu-
nately, on account of their high volatility and their
adverse affect on compatibility, the hitherto known
extender plasticizers can only be used to a very
limited extent and are employed almost exclusively to
reduce the viscosity the plastisol pastes in order to
guarantee their sprayability, especially by the airless
process.
Accordingly, the problem addressed by the present
invention was to find substances which would be
suitable as least as secondary plasticizers, which
would be physiologically safe and which would be
economically available in sufficient quantities. They
would preferably be based on renewable materials.
It has now surprisingly been found that monoesters
of monocarboxylic acids containing at least 12 carbon
atoms can replace the phthalic acid esters hitherto
used in PVC plastisols by up to 50~ without any adverse
effect on adhesion, stability in storage, tensile
c CA 022l~67~ l997-09-l6
H 1688 PCT 4
strength, elongation or resistance to water of
condensation. This is all the more surprising insofar
as, according to popular expert opinion, the esters of
monocarboxylic acids are regarded as too volatile, too
sensitive to water and too lacking in gelability to be
able to be used as plasticizers. On this very subject,
it is stated, for example, in Kunststoffhandbuch, Vol.
2/1, page 631, that the relatively long-chain esters of
fatty acids are also attended by compatibility problems
so that they cannot be classed as plasticizers for PVC.
They have a certain significance as low-temperature
plasticizers, secondary plasticizers and as lubricants
in the processing of rigid and flexible PVC. However,
particularly where they are used as lubricants, they
only added to the PVC mixtures in very small quantities
and are even expected to be incompatible with the
polymer because it is known that these lubricants are
supposed to migrate to the phase interface to develop
an anti-adhesive effect during the extrusion process
and other processing steps. There are no references in
the Kunststoffhandbuch to the use of the monoesters of
monocarboxylic acids of fatty acids containing at least
12 carbon atoms in PVC plastisols, particularly those
which are supposed to have a good adhesive effect on
coated and uncoated metal plates.
Secondary plasticizers suitable for use in accor-
dance with the invention are basically any C1_6 alkyl
esters of monocarboxylic acids containing at least 12
carbon atoms. Since the fatty acids for the monoesters
preferably emanate from natural sources, they are
CA 022l~67~ l997-09-l6
H 1688 PCT 5
generally mixtures of saturated and predominantly
unsaturated fatty acids with different chain lengths.
Dimethyl esters and/or ethyl esters of tall oil fatty
acids, rapeseed oil fatty acids, linseed oil fatty
acids and/or safflower oil fatty acids are most
particularly preferred.
Suitable primary plasticizers for the plastisols
according to the invention are basically any standard
plasticizers, including for example the C6_14 dialkyl
esters of phthalic acid, alkyl benzyl esters of
phthalic acid, benzoates of difunctional or
trifunctional polyols, for example dipropylene glycol
dibenzoate, alkyl sulfonic acid esters of phenol and
cresol, aryl phosphates, alkyl phosphates, C6_14 diesters
of aliphatic Cq_1o dicarboxylic acids and/or polymer
plasticizers based on diols and dicarboxylic acids and
mixtures thereof. The ratio of secondary plasticizer
to primary plasticizer is from 0.02:1 to 2:1 and
preferably from 0.07:1 to 0.06:1. On account of the
possibly health-damaging effect, however, the
plastisols according to the invention preferably
contain no dioctyl phthalate or dibutyl phthalate.
The other constituents of the plastisols according
to the invention are known per se. They are used in
the form of fine-particle polymer powders, preferably
polyvinyl chloride homopolymers and/or vinyl
chloride/vinyl acetate copolymers with a vinyl acetate
content of up to 20% by weight, based on the copolymer.
These PVC powders are normally produced as so-called
paste types by emulsion polymerization or
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H 1688 PCT 6
microsuspension polymerization. Suspension polymers,
which are also known as extender polymers, may be used
in addition to or instead of these paste types.
The methacrylate copolymers known from DE-B-24 54
235 and DE-B-25 29 732 and the styrene copolymers known
from DE-A-40 34 725 and DE-A-43 15 191 may also be used
for the plastisols according to the invention.
The plastisols according to the invention may also
contain the auxiliaries and additives known ln
plastisol technology, including for example epoxide
plasticizers, preferably epoxidized natural oils, such
as epoxidized soybean oil, epoxidized linseed oil or
epoxidized tall oils. These epoxy plasticizers are
known to be used in small quantities as heat
stabilizers, especially in PVC plastisols.
Any of the fillers typically used and known per se
in plastisol technology may be used as fillers.
Examples of suitable fillers are limestone powder,
natural ground chalks (calcium carbonates or calcium
magnesium carbonates), precipitated chalks, heavy spar,
talcum, mica, clays, pigments, for example titanium
dioxide, carbon black, iron oxides. The plastisols may
additionally contain standard antiagers and
stabilizers, rheology aids, for example pyrogenic
silicas, Bentones, castor oil derivatives. In
addition, so-called hollow microbeads may be used for
the production of plastisols of low specific gravity.
In addition, blowing agents may optionally be added to
the plastisols where they are to be foamed during the
gelation process. Suitable blowing agents are any
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H 1688 PCT 7
blowing agents known per se, preferably organic blowing
agents from the class of azo compounds, N-nitroso
compounds, sulfonyl hydrazides or sulfonyl
semicarbazides.
Azo-bis-isobutyronitrile and, in particular,
azodicarbonamide are mentioned as examples of azo
compounds while dinitrosopentamethylene tetramine is
mentioned as an example of a nitroso compound. 4,4'-
Hydroxy-bis-(benzenesulfonic acid hydrazide) is
mentioned as an example of a sulfohydrazide while p-
toluenesulfonyl semicarbazide is mentioned as an
example of a semicarbazide.
Foamed plastisols can also be obtained by using
thermoplastic microspheres. Thermoplastic microspheres
contain a liquid blowing agent based on aliphatic
hydrocarbons or fluorocarbons as core and a shell of a
copolymer of acrylonitrile with vinylidene chloride
and/or methyl acrylate and/or methacrylonitrile. Where
microspheres such as these are used, they expand and
hence cause the plastisols to foam during the gelation
process. The use of microspheres is described, for
example, in EP-A-559 254.
In many applications, coupling agents have to be
added. Various polyaminoamides based on polymerized or
dimerized fatty acids, epoxy resins, optionally in
combination with hot-curing crosslinking agents (for
example dicyanodiamide), phenolic resins,
terpene/phenol resins and (blocked) diisocyanates or
polyisocyanates may be used as coupling agents.
Polyaminoamides based on polyamines and dimerized or
CA 022l~67~ l997-09-l6
H 1688 PCT 8
polymerized fatty aclds are preferably used. The
coupling agents are normally used in quantities of 0.01
to 5% by welght, based on the plastlsol formulatlon as
a whole.
Accordingly, the plastisol compositions normally
consist of
- a) 5 to 50% by weight of at least one powder-form
polymer,
- b) 5 to 65% by weight of a plasticizer mixture of
primary plasticlzer and secondary plasticizer, the
ratio of secondary plasticizer to primary plasti-
clzer belng from 0.02:1 to 2:1 and preferably from
0.07:1 to 0.6:1,
- c) 0 to 50% by weight of fillers,
- d) 0.01 to 5% by weight of a coupling agent,
- e) optlonally other reactlve addltlves and other
auxiliaries and additives,
the sum total of the lndlvldual components belng 100%
by weight.
The plastisols according to the invention are
particularly suitable for use on metallic substrates in
painted or unpainted form, especially in automobile
constructlon. In automoblle construction, the
plastisols according to the invention are used as
underbody protectlon, as hood llning adhesives, as sill
protection compounds, as spot weldlng pastes and for
other adheslve applications. They may also be used to
seal weld seams or flanged seams and as acoustically
actlve coatlngs ("antl-vlbratlon compounds").
CA 0221~67~ 1997-09-16
H 1688 PCT 9
The invention is illustrated by the following
Examples which are intended to illustrate the effect of
the individual parameters on the present invention
without limiting the invention in any way.
The quantities mentioned in the following Examples
are parts by weight unless otherwise specifically
stated.
Example~ 1 to 4, C~mr~ison Example
In the following plastisol compositions, the indi-
vidual components were stirred in vacuo in a planetary
mixer with intensive shearing until the composition was
homogeneous.
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H 1688 PCT 10
Table 1
Example 1 2 3 4 Comp.
PVC Homopolymer2~17.0 117.o 117.0 117.o ¦17.0
PVC Homopolymer2)4.0 ¦ 4.0 ¦ 4.0 ¦ 4.0 ¦ 4.0
Diisononyl phthalate 37 ¦34 ¦30 ¦25 ¦40.0
Petroleum
190/250 3 1 3 1 3 1 3 1 5.0
Rapeseed oil methyl
ester3) 3 ¦ 6 llO ¦15 1--
Chalk, ground4)12.37 ¦12.37 ¦12.37 ¦12.37 ¦12.37
Calcium oxide 1.5 ¦ 1.5 ¦ 1.5 ¦ 1.5 ¦ 1.5
Zinc oxide 0.2 ¦ 0.2 ¦ 0.2 ¦ 0.2 ¦ 0.2
Carbon black paste0.03 ¦ 0.03 ¦ 0.03 ¦ 0.03 ¦ 0.03
Chalk, precipi-
tated 5) 13. 6 113. 6 ¦13.6 113. 6 ¦13.6
Chalk, precipi-
tated6) 5 0 ¦ 5.0 ¦ 5.0 ¦ 5.0 ¦ 5.0
Silica, highly
disperse 0.5 ¦ 0.5 ¦ 0.5 ¦ 0.5 ¦ 0.5
Polyaminoamide7~ 0.8 ¦ 0.8 ¦ 0.8 ¦ 0.8 ¦ 0.8
Viscosity [Pa-s] 8)1. 38 ~¦ 0.97 ¦ 0.83 ¦ 0.65 ¦ 1.30
Yield point
[Pa-s] 8)210 ¦172 ¦153 ¦142 ¦175
Shore hardness A44 ¦ 43 ¦ 44 ¦ 45 ¦ 44
AdhesionV.Good ¦V.Good¦V.Good¦V.Good¦V.Good
Exudation No ¦NO ¦NO ¦NO ¦NO
Tensile strength
[N/mm2] 1.87 ¦ 1.99 ¦ 1.96 ¦ 2.0 ¦ 2.04
Breaking elonga-
tion [%] 195 ¦190 ¦176 ¦162 ¦190
CA 022l~67~ l997-09-l6
H 1688 PCT 11
1) Emulsion polymer, paste type, K-value 72
2) Suspension polymer, K-value 65
3) Synonym: rapeseed oil fatty acid methyl ester
prepared by transesterification of rapeseed oil,
acid value 1, saponification value about 190,
iodine value about 110
4) Natural ground chalk, average particle size 2~
5) Precipitated stearate-coated chalk, average parti-
cle size 2.5
6) Precipitated chalk, average particle size 2.0~
7) Basis: dimer fatty acid, diethylenetriamine, amine
value about 240
8) Rheomat 115, measuring system 114.
To evaluate the gelled plastisols, the
compositions mentioned above were gelled for 30 minutes
at 165~.
To test adhesion, ribbons were applied to cata-
phoretically coated plates and subjected to the stoving
conditions mentioned above. This was followed by adhe-
sion testing in a manual peel test. After storage for
1 week at room temperature, the gelled samples were
examined to determine whether any liquid had exuded to
the surface of the plastigel. Tensile strength and
breaking elongation were determined in accordance with
DIN 53504 on gelled plastisol strips measuring lOxlxlO0
mm at a tear rate of 100 mm/min.
As can be seen from the above tests, the
performance properties of the plastigel, even with high
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H 1688 PCT 12
percentage contents of rapeseed oil methyl ester in the
formulations (Example 4), are equivalent to those of
the known plastigel which does not contain any rapeseed
oil methyl ester.
Example~ 5 to 8
In the Examples set out in Table 2, a test was
conducted on a simplified formulation to determine
whether other conventional plasticizers could be partly
replaced ~y rapeseed oil methyl ester in plastisols.
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H 1688 PCT 13
Table 2
Example 5 6 7 8
PVC Homopolymer, paste type 30 ¦ 30 ¦ 30 ¦ 30
Chalk, ground 40¦ 40 ¦ 40 ¦ 40
Polyaminoamide
Rapeseed oll methyl ester 201 20 ¦ 20 ¦ 20
Diisodecyl phthalate 10
Diisobutyl phthalate - ¦ 10
Alkyl sulfonic acid ester
of phenol - I _ ¦ 10
Polymer plasticizer based
on phthalic acid - I _ l _ ¦ 10
Diethylene glycol and
C7/C11 alcohol
Shore hardness "A" 71 ¦ 66 ¦ 67 ¦ 67
In order to be able to subject their gelation
behavior of the plastisols to a particularly critical
test, the plastisols were gelled with shortened stoving
times (17 mins./165~C). All the plastisol compositions
were completely gelled and did not show any exudation
of liquid constituents from the plastigel after storage
for several days at room temperature.
