Note: Descriptions are shown in the official language in which they were submitted.
214~71~
Ho~-H.~l ARTIEN~-R~RT-T-~ OEAFT HOE 94/F 090 Dr.DA/-
Description
Plastic molding composition treated with an antistaticagent
The invention relates to the use of certain betaines as
antistatic agent~ for thermoplastics, in particular
polyolefins.
High volume resistance and surface resistivity have
earned plastics an important position as insulating
materials in the electrical and electronics sector.
However, in all processes of separation from other media,
these same structure-dependent properties result in a
strong electrostatic charging of the surface. This is
undesirable for a variety of reasons:
15 - For the bulk of articles in daily use, the attrac-
tion of dust during storage and use should be
avoided on the grounds of esthetics and hygiene.
- In the processing of plastic parts having a large
surface area, e.g. sheets, fibers or powders, static
charging produces forces which interfere appreciably
with the process. They can prevent the proper win-
ding of calendered sheets or of fibers. During
processing or on dispensing units, film webs can
adhere to one another to an undesirable degree. In
the conveying of powders, lump formation or bridging
can occur. Also, the printability of finished parts
is impaired by static charging.
- Discharging processes can result in damage to packed
products.
30 - Spark discharge can cause severe accidents, e.g.
where there are dangers of fire and explosion when
214671S
-- 2
handling readily flammable gases, vapors and dusts,
e.g. when using solvents or in mines.
Attempts are made in all these areas to reduce the
chargeability of the plastic by means of suitable addi-
tives.
The conductivity of plastics can be increased in three
ways in order to avoid charging: surface application of
an "external" antistatic agent from a solution, incor-
poration of an "internal" (incorporable) antistatic agent
into the plastic, or incorporation of electrically
conductive additives (graphite, metals, organic semicon-
ductors).
Electrically conductive additives are used if the surface
resistance of the finished part is to be less than 108 Q.
Owing to the large amounts added of from 2 to 70%, the
mechanical properties are impaired.
External and internal antistatic agents are chemicals
which form a conductive film on the surface of the
plastic, generally in conjunction with the atmospheric
moisture. This can happen due to the production of a pure
film of moisture by means of water-attracting substances
or by the deposition of an organic electrolyte.
Both groups have a similar build-up principle: a
hydrophobic end ensures the anchoring of the additive to
the polymer surface and a strongly polar end absorbs
water molecules which eliminate charges according to the
principle of ion conductivity.
External antistatic agents are applied to the surface
from aqueous or solvent-containing preparations. More or
less all the surface-active compounds are effective, as
are also numerous hygroscopic substances such as
glycerol, polyols or polyglycols, which do not possess
the characteristic of surface activity. In the case of
3 2l~7l5
- - -
internal antistatic agents, the hydrophobic end of the
molecule is firmly anchored in the bulk of the polymer.
The majority of known antistatic agents can be subdivided
into cationic, anionic and nonionic compounds.
Cationic compounds generally consist of a bulky cation
often contA;n;ng a long alkyl radical (e.g. a quaternary
Ammo~;um, phosphonium or sulfonium salt), with it also
being possible for the quaternary group to occur in a
ring system (e.g. imidazoline). In most cases, the anion
is the chloride, methylenesulfate or nitrate ion derived
from the quaternization process. The quaternary ammonium
saltæ, in particular, have gained acceptance as com-
mercial products.
Cationic substances are most effective in polar polymers.
However, their use is restricted by their adverse effect
on the thermal stability of certain polymers.
Anionic compounds have an anion (usually an alkylsul-
fonate, alkylsulfate, alkylphosphate, dithiocarbamate or
carboxylate) as the active part of the molecule. The
cations used are frequently alkali metals or, more
rarely, alkaline earth metals. In practice, sodium alkyl-
8ul fonates, in particular, which develop a good
antistatic action in polar polymers, have gained accep-
tance. A disadvantage is that their use is limited to
muted colorations because of their tendency to produce
haze. On account of their very high melting range, sodium
alkylsulfonates are often very difficult to incorporate
homogeneously into the plastic to be treated, and their
hydrophilic character makes storage and proportioning
more difficult.
Nonionic compounds, for example polyethylene glycol
esters or ethers, fatty acid esters or ethanolamides,
monoglycerides or diglycerides or ethoxylated fatty
amineæ, are uncharged surface-active molecules whose
~ 4 -21167 l5
polarity is substantially lower than that of the ionic
compounds. Such products are usually liquids or waxy
substances having a low softening range. Their low
polarity and good compatibility makes representatives of
these classes of compounds ideal internal antistatic
agents for polyolefins. When used in large amounts, fatty
acid esters of monohydric and polyhydric alcohols provide
acceptable antistatic treatments, even in polar plastics,
and make it possible to manufacture transparent moldings,
in contrast to alkylsulfonates. Apart from the high use
concentration required, which can lead to processing
problems and affects mechanical and optical properties of
the molding~, the sometimes pasty consistency of these
products, with pour points above room temperature, has
proven disadvantageous for the use of these products.
To assess the effectiveness of antistatic agents in
molding compositions, there are, in particular, two
suitable methods. In the measurement of the surface
resistance in accordance with DIN 53482 (and since
DecPmher 1, 93, DIN IEC 93 (VDE 0303 part 30)), the
electrical resistance of the surface is measured by means
of a special electrode. Most organic polymers, such as
polyolefins, have natural surface resistances 2 1015 Q,
correspo~;ng to an R0 value (= logarithm to the base 10
of the surface resistance) of R0 = 15. Molding compo-
sitions which have surface resistances less than R0 = 11
(101l Q) are considered to have very good antistatic
treatments. Even smaller R0 values are excellent. The
second likewise very informative method, because it
directly measures the phenomenon of charging/discharging
of the ~urface, is the determination of the halflife.
Here, the time in which a charge applied to the surface
of the test specimen drops to half the initial value is
measured. Molding compositions having excellent
antistatic treatments achieve halflives below 5 seconds.
Many ionic and nonionic substances which can be used as
external or internal antistatic agents in plastics have
2146715
-- 5
already been described in the specialist literature.
Betaines have, inter alia, proven to be effective in
principle. The antistatic action of alkyl betaines in
polyolefins (cf. US 3,005,793) is known. Also known is
the use of alkylaminoalkyl betaines as internal
antistatic agents in polymers (cf. JP-Sho 44-13587).
In the use of the incorporable antistatic agents hitherto
known, various disadvantages occur which become notice-
able in the processing or the use of the treated plastic.
These include insufficient thermal stability, high
melting range, a t~n~ency to haze formation, high use
concentration and pasty consistency.
Materials having a longer-lasting action (for example
ethoxylated fatty amines) often show an antistatic effect
on the surface of polyolefins only after many days.
Substances which act rapidly because they rapidly migrate
to the surface, on the other hand, usually cause a
surface deposit which, for example, impairs the ability
of the plastic to be written on or printed or to have a
seal affixed. In addition, antistatic agents in many
cases impair the color and, in the case of clear or
translucent polymers, the transparency of the treated
molding compositions.
It has now been found that certain alkylamidopropyl
betaines develop an antistatic action in polyolefins
unusually quickly, without resulting in disadvantageous
surface effects.
The invention thus provides a plastic molding composition
treated with an antistatic agent, comprising from 94 to
99.99% by weight, based on the molding composition, of a
thermoplastic or thermoset plastic and from 0.01 to 6% by
weight, based on the molding composition, of a compound
of the formula I
6 21~67i~
R~
R1-CONH-R2N~-CN2-COO-
(I)
where Rl i8 a saturated or unsaturated aliphatic hydro-
carbon group having 8 or more carbon atoms,
R2 is a C1-C6-alkyl group and
R3 and R4 are identical or different and are each a
symmetric or unsymmetric alkyl group, hydroxyalkyl group
or polyoxyalkylene group.
The plastic molding composition of the invention contains
a thermoplastic or thermoset organic polymer, for example
one of those listed below:
1. Polymers of monoolefins and diolefins, for
example polyethylene of high, medium or low density
(which may be uncrosslinked or crosslinked),
polypropylene, polyisobutylene, polybut-1-ene, poly-
methylpent-1-ene, polyisoprene or polybutadiene and also
polymers of cycloolefins such as, for example, of cyclo-
pentene or norbornene.
2. Mixtures of polymers specified under 1) for
example mixtures of polypropylene with polyethylene or
with polyisobutylene.
3. Copolymers of monoolefins and diolefins with one
another or with other vinyl monomers, for example
ethylene-propylene copolymers, propylene-but-1-ene
copolymeræ, propylene-isobutylene copolymers, ethylene-
but-1-ene copolymers, propylene-butadiene copolymers,
isobutylene-isoprene copolymers, ethylene-alkyl acrylate
copolymers, ethylene-alkyl methacrylate copolymers,
ethylene-vinyl acetate copolymers or ethylene-acrylic
214671~
-- 7
acid copolymers and their salts (ionomers), and also
terpolymers of ethylene with propylene and a diene such
as hexadiene, dicyclopentadiene or ethylidenenorbornene.
4. Polystyrene, poly(p-methylstyrene).
5. Copolymers of styrene or ~-methylstyrene with
dienes or acrylic derivatives, for example styrene-
butadiene, styrene-maleic anhydride, styrene-
acrylonitrile, styrene-ethyl methacrylate, styrene-
butadiene-ethyl acrylate, styrene-acrylonitrile-
methacrylate; mixtures having high impact toughne~s ofstyrene copolymers and another polymer such as, for
example, a polyacrylate, a diene polymer or an ethylene-
propylene-diene terpolymer; and also block copolymers of
styrene, for example styrene-butadiene-styrene, styrene-
isoprene-styrene, styrene-ethylene/butylene-styrene or
styrene-ethylene/propylene-styrene.
6. Graft copolymers of styrene, for example styrene
on polybutadiene, styrene and acrylonitrile on polybuta-
diene, styrene and maleic anhydride on polybutadiene,
styrene and alkyl acrylates or alkyl methacrylates on
polybutadiene, styrene and acrylonitrile on ethylene-
propylene-diene terpolymers, styrene and acrylonitrile on
polyalkyl acrylates or polyalkyl methacrylates, styrene
and acrylonitrile on acrylate-butadiene copolymers, and
also their mixtures with the copolymers specified under
5) which are known, for example, as so-called ABS, MBS,
ASA or AES polymers.
7. Polyvinyl chloride.
8. Copolymers of vinyl chloride which can be pre-
pared by known processes (for example, suspension, bulkor emulsion polymerization).
9. Copolymers of vinyl chloride with up to 30% by
weight of comonomers such as, for example, vinyl acetate,
21~671~
-- 8
vinylidene chloride, vinyl ether, acrylonitrile, acrylic
esters, monoesters or diesters of maleic acid, or ole-
fins, and also graft polymers of vinyl chloride.
10. Halogen-cont~;n;ng polymers such as, for example,
5 polychloroprene, chlorinated rubber, chlorinated or
chlorosulfonated polyethylene, homopolymers and
copolymers of epichlorohydrin, in particular polymers of
halogen-containing vinyl compounds such as, for example,
polyvinylidene chloride, polyvinyl fluoride,
10 polyvinylidene fluoride; and also their copolymers such
as of vinyl chloride-vinylidene chloride, vinyl chloride-
vinyl acetate or vinylidene chloride-vinyl acetate.
11. Polymeræ derived from cY,,~-unsaturated acids and
their derivatives, such as polyacrylates and polymeth-
15 acrylates, polyacrylamides and polyacrylonitriles.
12. Copolymers of the mor~o~ers specified under 11)with one another or with other unsaturated monomers, such
as, for example, acrylonitrile-butadiene copolymers,
acrylonitrile-alkyl acrylate copolymers, acrylonitrile-
20 alkoxy acrylate copolymeræ, acrylonitrile-vinyl halide
copolymers or acrylonitrile-alkyl methacrylate-butadiene
copolymers.
13. Polymers derived from unsaturated alcohols and
amines or their acyl derivatives or acetals, such as
25 polyvinyl alcohol, polyvinyl acetate, stearate, benzoate,
maleate, polyvinyl butyral, polyallyl phthalate, poly-
allyl melamine.
14. Homopolymers and copolymers of cyclic ethers such
as polyethylene glycols, polyethylene oxide,
30 polypropylene oxide or their copolymers with diglycidyl
etheræ.
15. Polyacetals such as polyoxymethylene, and also
those polyoxymethylenes which contain comonomers such as,
214671~
g
for example, ethylene oxide.
16. Polyphenylene oxides and sulfides and their
mixtures with styrene polymers.
17. Polyurethanes derived from polyethers, polyesters
and polybutadienes having terminal hydroxyl groups on the
one hand and aliphatic or aromatic polyisocyanates on the
other hand and also their precursors (polyisocyanate-
polyol prepolymers).
18. Polyamides and copolyamides derived from diamines
and dicarboxylic acids and/or aminocarboxylic acids or
the correspo~;ng lactams, such as polyamide-4,
polyamide-6, polyamide-6.6, polyamide-6.10, polyamide-11,
polyamide-12, poly-2,4,4-trimethylhexamethylenetere-
phthalamide, poly-m-phenyleneisophthalamide, and al~o
their copolymers with polyethers, for example with
polyethylene glycol, polypropylene glycol or polytetra-
methylene glycol.
19. Polyureas, polyimides and polyamide-imides.
20. Polyesters derived from dicarboxylic acids and
diols and/or from hydroxycarboxylic acids or the corres-
po~; ng lactones, such as polyethylene terephthalate,
polybutylene terephthalate, poly-1,4-dimethylolcyclo-
hexane terephthalate, poly(2,2-bis(4-hydroxyphenyl)-
propane) terephthalate, polyhydroxybenzoates, and also
block polyether esters derived from polyethylene having
hydroxy end groups, dialcohols and dicarboxylic acids.
21. Polycarbonates and polyester carbonates.
22. Polysulfones, polyether sulfones and polyether
ketones.
23. Crosslinked polymers derived from aldehydes on
the one hand and phenols, urea or melamine on the other
lo 2116715
,
hand, such as phenol-formaldehyde, urea-formaldehyde and
melamine-formaldehyde resins.
24. Drying and nondrying alkyd resins.
25. Unsaturated polyester resins derived from copoly-
esters of saturated and unsaturated dicarboxylic acidswith polyhydric alcohols, and also vinyl compounds as
crosslinkers, as well as their halogen-cont~;n;n~,
flame-resistant modifications.
26. Crosslinkable acrylic resins derived from substi-
tuted acrylic esters, for example epoxy acrylates,urethane acrylates or polyester acrylates.
27. Alkyd resins, polyester resins and acrylate
resins which are crosslinked with melamine resins, urea
resins, polyisocyanates or epoxy resins.
28. Crosslinkable epoxy resins derived from poly-
epoxides, for example from diglycidyl ethers or from
cycloaliphatic diepoxides.
29. Natural polymers such as cellulose, natural
rubber, gelatin and also their derivatives which are
chemically modified in a polymer-homologous manner, such
as cellulose acetates, propionates and butyrates, or
cellulose ethers such as methylcellulose.
30. Mixtures of the abovementioned polymers such as,
for example, PP/EPDM, polyamide-6/EPDM or ABS, PVC/EVA,
PVC/ABS, PVC/MBS, PC/ABS, PBTP/ABS, PC/ASA, PC/PBT,
PVC/CPE, PVD/acrylate, POM/thermoplastic PUR,
POM/acrylate, POM/MBS, PPE/HIPS, PPE/polyamide-6.6 and
copolymers, PA/ HDPE, PA/PP, PA/PPE.
31. Naturally occuring and synthetic organic
materials which are pure mo~-ers or mixtures of mono-
mers, for example mineral oils, ~n;~-l and plant fats,
- - 11 214671~
oils and waxes, or oils, fats and waxes based on syn-
thetic esters or mixtures of these materials.
32. Aqueous diRpersions o$ natural or synthetic
rubber.
Preferred polymers are polyolefins such as, for example,
polyethylene of various densities such as LDPE, MDPE,
HDPE, LLDPE and polypropylene, and also polyRtyrene and
polyvinyl chloride. Particular preference is given to the
polyolefins.
As antistatic agent, the plastic molding composition of
the invention contains a compound of the formula I
R~-CONIl-R2N~-CH2-COO
R~
( l )
where R1 is a saturated or unsaturated aliphatic hydro-
carbon group having 8 or more carbon atoms, preferably a
C8-C22-, in particular C12-C14-alkyl group,
R2 is a C1-C6-, preferably C3-alkyl group and
R3 and R4 are identical or different and are each a
symmetric or unsymmetric alkyl group, hydroxyalkyl group
or polyoxyalkylene group, but are preferably identical
and are each a methyl group.
Particular preference is given to a betaine in which Rl
is a fatty acid amidopropyl group. The preferred fatty
acid is coconut fatty acid:
~ - 12 - 21~6715
CH
Rcoconut~C~N~CH2~CH2~CH2~N~~CH2-COO~
O ~1 CH~
The antistatic agent to be used according to the inven-
tion iB preferably prepared by reaction of the sodium
salt of monochloroacetic acid with fatty acid amido-
propyldimethylamine. This also results in the formation
of one mol of NaCl per mol of the betaine. The reaction
is carried out in solution. The dry residue contains, for
complete equimolar reaction, considerable amounts of
NaCl.
If the synthesis of the alkylamidoalkyl betaine is
carried out in aqueous solution, the water has to be
removed prior to the preparation of the molding composi-
tion treated with the antistatic agent, since the water
interferes with processing. It has been able to be shown
that alkylamidoalkyl betaine can also be prepared in the
presence of other surfactants which serve as solvents in
the synthesis and which in turn have an antistatic
action. Such surfactants or surfactant-like materials
are, for example, polyethylene glycols, polypropylene
glycols, ethylene oxide/propylene oxide derivatives with
or without a hydrocarbon radical, ethoxylated fatty
acids, ethoxylated fatty alcohols and surfactant mix-
tures, with or without the further addition of solvents.
Compounds of the formula I are known per se and some of
them are commercially available. The commercial products
here contain, apart from compounds of the formula I,
further materials which may be present as a result of the
synthesis. Typical is a content of from about 10 to 20%
by weight of NaCl. The NaCl content is advantageous to
the antistatic action.
2146715
_ - 13 -
Compounds of the formula I are often prepared in 801u-
tion. The solvent can be water, 80 that the commercial
product i8 often obtained in the form of an aqueous
solution and is also sold in this form. The solution is
suitable for direct application to finished parts, with
the anti~tatic agent acting externally. In particular
synthetic proces~es, the antistatic agent is obtained
together with further substances, with the process
allowing another antistatic agent to be used as solvent.
The formulation thus prepared can be used a~ a combina-
tion antistatic agent.
Materials of the formula I can be mixed with other
materials, for example with other antistatic agent~.
The antistatic agent to be used according to the
invention is incorporated into the polymers using the
customary methods. The incorporation can, for example, be
carried out by m; Y; ng the compound and, if desired,
further additives into the melt before or during shaping.
The incorporation can also be carried out by application
of the dissolved or disper~ed compound directly onto the
polymer or mixing into a solution, suspension or emulsion
of the polymer, if desired allowing the solvent to
subsequently evaporate. The amount to be added to the
polymer is, for incorporation, from 0.01 to 6% by weight,
preferably from 0.06 to 4% by weight, in particular from
0.1 to 3% by weight, based on the material to be treated.
The compound or formulation can al~o be added to the
polymer to be treated in the form of a masterbatch or
additive concentrate which contains from 2.5 to 70% by
weight of the compound or formulation.
The plastic molding composition can additionally contain
the customary additives such a~, for example, anti-
oxidants, plasticizers, impact modifiers, processing aids
and stabilizers, light ~tabilizer~, lubricant~, filler~,
flame retardants, blowing agents, pigments, dyes or
colorants and also other antistatic agents.
2146~15
- 14 -
_
It has been found that a certain amount of sodium chlor-
ide in the alkylamidopropyl betaine gives a further
significant improvement in the antistatic action, which
becomes apparent in a lower surface resistance, a shorter
halflife and a lower chargeability of the treated plastic
part. Since NaCl alone in small amounts in molding
compositions has hardly any antistatic action, but
together with the alkylamidopropyl betaine gives better
antistatic properties, there is obviously synergy between
the two materials.
The plastic molding composition of the invention has the
advantage that the antistatic action commences very
quickly after processing. In comparison with the ethox-
ylated alkylamines which are considered excellent, the
antistatic treatment commences its action more quickly
and for a low dosage gives effective prevention of dust
attraction even on the day of production. A further
advantage of the molding composition treated according to
the invention is that the surfaces of the treated
articles do not become moist by sweating out, as i~ the
case for other antistatic agents. The surfaces remain
able to have seals affixed, dry and printable. An import-
ant advantage is the low dosage amount which is required
to achieve the effect. The dosage amount is even less
than that of the ethoxylated alkylamines, which are known
as very effective, without possessing the same disadvan-
tages as this class of materials, such as basicity,
corrosivity or fish- toxicity. In comparison with sub-
stances such as alkylsulfonates, fatty acid esters and
others, the dosage of the substances to be used according
to the invention in molding compositions is lower anyway.
In a practicable dosage, the substances to be used
according to the invention lead to virtually no adverse
effects on the color and the transparency of the molding
composition. Certain alkylamidoalkyl betaines possess the
additional advantage of being solids which, for example
as ready-made spray-dried powder, can be metered into the
molding composition to be treated in a technically simple
21~67i~
manner.
The following examples serve to illustrate the invention.
Examples
In the following examples, antistatic agents of formula
I were incorporated into plastic molding compositions.
The surface resistance in accordance with DIN 53482 and
the halflife were determined on the test specimens
produced from the molding composition. Some known,
commercially available antistatic agents were used for
comparison.
Representatives of substances of the formula I which were
used were:
(A) Coconut amidopropyl betaine, product containing from
about 15 to 20% of NaCl.5 (Al) Product as in (A) but with the salt removed by
extraction with ethanol (NaCl c2%).
(A2) Product as in (A), synthesized in ethoxylated coco-
nut fatty alcohol as solvent remaining in the
product.
(A3) Tallow/oleyl-(8:2)-amidopropyl betaine.
The comparisons used were:
(B) Ethoxylated fatty amine (N,N-bis(2-hydroxyethyl)
coconut fatty amine).
(C) Fatty acid ester
(D) Ethoxylated fatty acid amide
(E) Lauryl betaine
The antistatic properties of the pure technical polymer
were measured after identical processing as a comparison.
The surface resistance was measured by the current/
voltage method. The measurement resistance here is
106-10l5 Q. The values given for the surface resistance
2146715
- 16 -
and halflife are in each case means of at least six
individual measurement values. The results were
determined from the value of the logarithm of the surface
resistance. Measurement values lying above the
measurement range of 1015 Q were given the value 15 for
the calculation of the mean. The halflife was monitored
over 60 seconds. Measurement results in which the charge
had not fallen to half of the initial charge within 60
seconds were given a value of 60 seconds in the averaging
of the results. Thus, for the average halflives given,
values above about 40 seconds are imprecise. If the
halflife of all measurements was at least 60 seconds, the
results were denoted by "~60n. The values in the
following tables were measured at the indicated point in
time after production of the test specimens. After
production of the test specimens, these were stored and
measured in a room having stAn~rd atmospheric conditions
(temperature: 23C, relative atmospheric humidity 50%).
In addition, the yellowness index and the transparency
were determined on the test specimens.
Example 1
Low-density polyethylene (LDPE)
LDPE powder was mixed in a mixer (Papenmeier, type TLHK3)
with the amounts shown in the table of the respective
test substance for a mixing time of 3 minutes at ambient
temperature. The mixture was granulated twice by means of
an extruder (Leistritz LSM 30/34) (zones 1 to 7, tempera-
tures: 150/155/160/170/180/190/190C). The maximum
composition temperature during extrusion reached about
205C. The cooling of the extrudate prior to granulation
was carried out in a waterbath. Plates were injection-
molded from the granular materials thus obtained using an
injection-molding machine (Windsor SP 50, zones 1 to 4,
temperatures: 190/200/200/210C) at a composition tem-
perature of about 220C. The thickness of the plates wa~
2146715
- 17 -
1 mm.
Table 1: Antistatic treatment of LDPE molding compoQi-
tions with (A) and ~A1)
On lRt day after On 7th day after
production production
Surface Half- Surface Half-
resist- life resiQt- life
ance ance
Product Do~ageRO TimeRO Time
[log Q] [~ec][log Q] [sec]
LDPE - ~ 14 ~ 60~ 14 ~ 60
(A) 0.2 9.6 3.39.4 ~ 1
(A1) 0.2 11.7 25.89.6 ~ 1
Table 2: Color and transparency of the test ~pecimeng
(LDPE)
Product Dosage Yellowness Index Transparency
[%]
LDPE - -0-5 44-7
(A) 0.2 -0.3 44.1
(B) 0.2 2.8 40.9
2146715
- 18 -
Table 3: Comparison of various products, surface resist-
ance and halflife (LDPE)
On 1st day after On 7th day after
production production
Surface Half- Surface Half-
resist- life resist- life
ance ance
Product Dosage RO TimeRO Time
[log Q] [sec][log Q] ~sec]
LDPE - ~ 14 ~ 60~ 14 ~ 60
(A) 0.1 10.0 3.4 9.5 ~ 1
(A2) 0.1 13.4 41.8 9.8 2.3
(A3) 0.1 12.9 ~ 6011.7 6.1
(B) 0.1 11.4 5.2 9.7 ~ 1
(E) 0.1 ~ 14 ~ 60~ 14 ~ 60
Example 2
Production of test specimens from high-density
polyethylene (HDPE)
HDPE powder (density 0.96 g/cm3, MFI 190/2 7 g/10 min,
MFI 190/5 25 g/10 min) was mixed in a mixer (Papenmeier,
type TLHR3) with the amounts shown in the table of the
respective test substance for a mixing time of 3 minutes
at ~mhient temperature. The mixture was granulated twice
by means of an extruder (Gottfert instrumented extruder,
type 015, rheological screw 5/2, zones 1 to 3, tempera-
tures 180/190/210C). The cooling of the extrudate prior
to granulation was carried out in a waterbath. Plates
were injection-molded from the granular materials thus
obtained using an injection-molding machine (Windsor SP
50; zones 1 to 4, temperatures 190/200/200/210C) at a
composition temperature of about 220C. The thickness of
214671~
- 19 -
the plates was 1 =.
Table 4: Surface resi~tance and halflife measured on
HDPE molding composition~
On 1st day after On 14th day
production after production
Surface Half- Surface Half-
resist- life resist- life
ance ance
Product Dosage RO Time RO Time
~log Q~ ~sec] ~log Q] ~sec]
HDPE - ~ 14 60 ~ 14 60
(A) 0.5 10.9 27 9.0
(A) 0.1 14.5 60 9.0 2
Example 3
Production of test specimens from polypropylene (PP)
PP powder (MFI 230/5 3 g/10 min) was mixed in a mixer
(Papenmeier, type TLHK3) with the amounts shown in Table
5 of the test substance for a ~;Y; ng time of 3 minutes at
ambient temperature. The mixture was granulated twice by
means of an extruder (Gottfert instrumented extruder,
type 015, rheological screw 5/2, zone~ 1 to 3, tempera-
tures 200/220/240C). The cooling of the extrudate prior
to granulation was carried out in a waterbath. Plates
were injection-molded from the granular materials thus
obtained using an injection-molding machine (Windsor SP
50; zones 1 to 4, temperatures 200/210/210/220C). The
thickness of the plates was 1 mm.
2146715
- 20 -
Table 5: Surface resistance and halflife measured on PP
molding compositions
Surface resistance Halflife
RO [log Q] Time [sec~
Pro- Dos- 1st 14th 52nd 1st 14th 52nd
duct age day day day day day day
PP ~ 14~ 14 ~ 14 ~ 60 ~ 60 ~ 60
(A) 1.0 10.0 9.1 8.6 c 1 _ ~ 1
(A) 0.5 15.010.7 - ~ 60 22
(C) 2.0 14.110.8 13.2 ~ 60 2 53
(D) 0.5 15.012.2 - ~ 60 25
