Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~S58~8
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HOE B4/F 909
The ;nvention relates to a film with a matt and
rough surface, wh;ch consists of a major proportion of a
lo~ molecular v;nyl chloride polymer and a minor proportion
of a high molecular vinyl chloride polymer and a f;ller, as
~ell as lubrican~s and a heat stabilizer, and which has
been produced by the roll kneading/calendering processu
A film of this type, with ~itanium diox;de as the
f;ller, is kno~n from the t~o German Offenlegungsschr;ften
1,815,891 and 2,716,853. This film not only leaves some-
th;ng to be desired conserning mattness but above alldoes not have good contact transparency, i.e. a pic-
ture vie~ed through the f;lm, for example a ~r;tten text
placed under the f;lm~ appears relatively cloudy and hence
does not have good contrast. This so-called internal
cloudiness ;s also exhibited by films which ;nstead of
titanium dioxide contain other fillers of this type, such
as are recommended, for example, in German Offenlegungs-
schrift 2,844,687, namely alum;num oxide, talc and, prefer-
ably~ chalk. It is true that in the absence of these
fillers the film has good contact transparency, but it ;s
even less matt than the corresponding films containing
filler, and this manifest~ itself in a relatively h;gh
g ~oss O
It is furthermore known~ from German Offenlegun~s-
schrift 2,629,742, that upon salendering of mixtures basedon vinyl chloride polymers, using the roll kneading/calen-
dering process~ a film having a matt and rough surfase is
obtained if the last t~o calender rolls are run at a cir-
cumferential speed ratio tfriction settlng) of 1.3 to 20,
preferably 1.6 to 10. This film, again, has the above-
mentioned d;sadvantages.
It has also already been recommended to use starch
as a filler in polyvinyl chloride films~ in order thereby
to increase the biological degradability (Ind. Eng~ Chemu,
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Prod. Res. Develop~ VolO 13, No. 2, 1974, 123 to 125).
It is the object of the invention to provide a
filler ~hich, in films based on vinyl chloride polymers
~ith relatively widely d;fferent molecular weights (degrees
of polymerizat;on, K values) produces good mattness and
roughness and at the same time the least possible ;nternal
cloud;ness. Accordingly, the object of the invention ;s in
particular to provide a film of the type mentioned at the
outset, ~hich exhibits high mattness and roughness coupled
with high contact transparency.
This object is achieved, according to the inven
tion, by a film which consists of
a) 65 to ~7X by weight, preferably 75 to 93X by weight,
of a low molecular vinyl chloride polymer having a K value
of 50 to 67,
b) 2 to 30X by wei~ht, preferably 5 to 15X by weight,
of a high molecular vinyl chloride polymer having a K value
of 70 to 90 and
c) 1 to 15X by ~e;ght, preferably 2 to 10X by ~eight,
- 20 of starch as a filler,
the percentages by weight being based on the sum of the
weights of the three components, ~hich amounts to 100 per-
cent by ~eight n
The low molecular vinyl chloride polymer has a K
value of preferably 55 to 60 and the high molecular vinyL
chloride polymer a K value of preferably 75 to 90~ The
advantageous difference in K values bet~een the high mole-
cular vinyl chloride polymer and the lo~ molecular vinyl
chloride polymer follo~s on the one hand in particular from
the desired matt effect, ~hich also increases with increas~
ing differences in K value, and on the other hand from the
desired calenderability, which decreases with increasing dif-
ferences in K value, namely becomes more difficult. Accord-
ingly, the d;fference in K values of the v;nyl chloride
polymers of cornponents a) and b) is in general 3 to 30
units, preferably 10 to 25 units.
A fil~ preferred according to the invention con~
sists of
s~
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a) 75 to 93% by ~eight of a low molecular vinyl
chloride polymer haY;ng a K value of S0 to 67, preferably
~5 t~ 60,
b) 5 to 15% by we;ght o~ a h;gh molecular v;nyl
chlor;de polymer hav;ng a K value of 70 to 90, preferably
75 to 90 and
c) 2 to 10X by ~e;ght of starch.
As vinyl chloride polymers, it is poss;ble to
employ v;nyl chlor;de homopolymers or v;nyl chloride co-
polymers ~h;ch have been produced by one of the customarypolymerizat;on processes, namely by emulsion polymerization~
suspension polymer;zation or mass polymer;zation, preferably
by suspens;on polymer;zation or mass polymerization. The
proport;on of the comonomers ;n the copolymers ;s in
general at most 20X by weight, preferably 1 to 10X by
~eight, the percentages by we;ght be;ng based on the co-
polymer. Suitable copolymers are those of vinyl chlor;de/
v;nyl acetate, vinyl chlor;de/ethylene/v;nyl acetate, vinyl
chlor;de/maleimide and vinyl chlor;de/acrylate or meth-
acrylate, preferably ~;th up to 5 carbon atoms in theesterified alcohol rad;cal. Vinyl chloride homopolymers
; are preferred.
The K value of the vinyl chloride polymer ~which
corresponds to the mean degree of polymerizat;on or the mean
molecuLar ~eight) ;s adjusted, as is known, by ma;nta;ning
an appropr;ate temperature during the polymer;zat;on and/or
by add;t;on of regulators~ The K value of a v;nyl
chloride poly~er is determined accord;ng to DIN 53 726,
;.e. uith cyclohexanone as the solvent (K values according
to H. Fikentscher~. The vinyl chlor;de polymers to be
employed accord;ng to the ;nvent;on are soluble ;n th;s
solvent.
As starch~ ;t ;s poss;ble to employ natural or
synthet;c tcrosslinked) pulverulent starch products. Su;t
able starches are cereal starches such as rye, wheat, oat
or ba~ley starch, corn starch, rice starch and potato starch.
The starch po~der ;n general cons;sts of s;mple or
agglomerated particles of var;ous shapes (egg-shaped, lens-
..
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shaped, roundish or polygonal). The particle diameter(the particle size) of the starch to be employed according
to the invention can vary within ~ide limits. A starch
~ith a mean particle d;ameter of 0.004 to 0.15 mm is pre-
ferred. Advantageously~ a starch powder whose particlediameter is less than the thickness of the desired film is
used.
The heat stabilizers preferentially employed are
the organo-tin sulfur compounds~ aminocrotonic acid esters,
urea and thiourea derivatives and/or salts of alkal;ne
earth metals and zinc, customary for vinyl chloride poly-
mers. The organo-tin sulfur stabilizers, such as dimethyl-
tin~ dibutyl-tin and dioctyl-tin bis-Z-ethyl-hexylthio-
glycolate, are preferred. The effective amount of stabi-
l;zer is usually 0.5 to 3X by weight, preferably 1 to 2X by~eight, based on the amount by ~eight of vinyl chlor;de
polymer.
Preferably the following compounds, customary in
vinyl chloride polymers, are employed as lubricants:
stearic acid, montan acid, glycerol esters such as glycerol
monooleate, bis-palmitoylethylenedia~ine, bis-stearoyl-
ethylenediamine and montan ac;d esters of ethanediol or
1,3-butanediol, optionally partially saponified. The
effective amount of lubricant is usually 0.1 to 2.5X by
~eight, preferably 0~5 to 1.5X by weight, based on the
amount by ~eight of vinyl chloride polymer.
Where the film according to the invention i~ to be
formulated, for example, to have ;ncreased impact strength
or a particular colour, or to be antis~at;c andtor non-
flammabLe, it may contain appropriate additives~ each in aneffective amount. Suitable impact strength modifiers are
the polymers~ customarily used w;th polyvinyl chloride~ of
acrylon;trile/butad;enetstyrene, methyl ~ethacrylate/
acrylonitriletbutad;enetstyrene, methyl methacrylate/buta-
dienetstyrene and methyl methacrylate~ as ~ell as chlorina-
~ed pQlyethylene. Coloration to give, for example, red,
~reen and the like is effected ~ith the aid of appropriate
colorants. White coloration is preferably effected with
, . .. .
s~
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the aid of t;tanium d;oxide andtor chalk. Preferred ant;-
stat;c agents are the quaternary ammon;um salts customary
for polyvinyl chloride films. Antimony trioxide is a par-
t;cularly suitable flameproofing agent for polyvinyl
chloride.
~ he preparat;on of the m;xtures ~hich serve as the
starting mater;al for the product;on of the film according
to the invention is effected by m;xing the ind;vidual com--
ponents, advantageously in a mixer conventionally used in
plastics processing.
The fiLm according to the invention is prepared by
the roll knead;ng/calendering process, also referred to as
high temperature calendering process~ In this calendering
process, as ;s known, the prepared vinyl chlor;de polymer
mixture is first preplasticized. The preplasticized mass
is then milled on a calender consisting of at least three,
preferably three to six, especially four to five, rolls, to
give a f;lm, ~;th a rotating "sausage" being formed in
front of the roll nips. This sausage consists of excess
thermoplastic material ~h;ch is in a state of thermal
plastic;ty and rotates ;n contact w;th t~o hot rolls ;n
front of the n;ps. The rotat;on of the ;nd;v;dual calender
rolls ;s in general set so that the circumferential speed
increases from roll to roll in the direction of trav~l of
the material and the friction ti.e. the ratio of ~he
circumferential speeds of two adjacent rolls) is about
1~05 to 1.2 in the first nip, ~hile the frictions in the
subsequent n;ps are about 1.05 to 1.15. In the roll knead~
;ng/calendering or h;gh temperature calender;ng process the
calender rolls are heated to relat;vely h;gh temperatures
(in contrast to the low temperature calendering process,
also referred to as the luv;therm process). In the case of
calender;ng of mixtures based on vinyl chloride polymers,
the calender rolls are ;n generai heated to 16U - 230C,
preferably to 170 ~ 210co The rolls preceding the last
calencler roll ~in the direction of travel of the material9
in general have a te~perature ~hich increases from roll to
roll or is substantially constant, or are heated so that
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the first roll has a h;~her temperature than the subsequent
rolls, ~h;ch in turn have an ;ncreas;ng or substant;ally
constant temperature. The last calender roll ;n general
has a lo~er temperature, at least than the preced;ng roll.
Transfer of the mill hide (the f;lm web) from one calender
roll to another ;s ensured by the temperature program and/
or by the fr;ct;on. The calendered f;lm ;s taken off the
last calender roll and ;s wound up after it has cooled~
In producing the f;lm accord;ng to the invention
by the roll kneading/calendering process, it has proved
advantageous to set the friction ;n the last roll n;p to a
substantially higher value than is generally customary in
polyvinyl chloride calendering, in part;cular to 1.2 - 1.6,
preferably 1~3 - 1.4. As regards the temperature of the
calender rolls, ;t is in the temperature range customary
for roll kneading/calendering of polyvinyl chloride. The
production of the film according to the invention by the
roll kneading/calendering process on a calender consisting,
for example, of four rolls is accordingly carried out at a
calender roll temperature of 160 to 230C, preferably 170
to 210C, w;th a friction of the last pair of rolls (;n
the direction of travel of the material~ of 1.7 to 1.6,
preferably 1.3 to 1.4~ At the same time, the individual
rolls are preferably so heated that the temperature of the
first t~o rolls (in the direction of travel of the material)
is 170 to 200C, the temperature of the third roll is 200
to 210C and the temperature of the fourth roll is 180 to
190C. The calendered film is taken off the last calender
roll, cooled by means of chiLl rolls and ~ound upO
The thickness o~ the f;lm accord;ng to the inven
tion is in general 0.1 to 1 m~, preferably 0.2 to 0.7 mm.
The invention is no~ explained in more detail with
re~erence to examples.
The components listed in the examples wh;ch follo~,
together ~ith a lubricant and a heat stabilizer for poly-
vinyl chloride~ were mixed in a high-speed mixer customary
in plast;cs processing. The mixture was pregelled on a
mixing mill at a temperature of 160 to 1~0OC. A film ~as
~;~s~
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calendered from the pr~gelled mater;al on a four-roll calen-
der, ~ith formation of a sausage ;n front of each n;p, the
first two rolls (in the direction of trav~l of the material)
being heated to 190 - 200C, the third roll to 200 - 210C
and the fourth roll to 180 - 190C, and the fric'c;on ;n the
last nip being set to 1.3. The calendered film ~as taken
off the last calender roll, cooled by means of chill rolls
and uound up. The thickness of the film obtained was 0.2 mm
in each case.
The followiny properties; of the fil~s ~ere tested:
- 1. the surface roughness accorcling to DIN 4768, the mean
peak-to-valley distance Rz being determined;
2. the gloss according to DIN 67 530, at an angle of
measurement of 85 ~gloss value);
the contact transparency according to ASTM 1003~ in
which method a piece of film is ;ntroduced into a cell
filled with tetralin and this cell (~ith the tetralin and
the piece of film) constitutes the measurement sample for
measurement of turbidity according to ASTM 1003. The
effect of d;pping the piece of film to be tested into
tetralin is that only the cloudiness tmaterial cloudiness,
internal cloudiness) emanating from the interior of the
piece of film is measured, since film surface effects such
as surface mattness are eliminated due to the identical
refractive index of tetralin and the piece of film (tetra-
l;n, as is known, has the same refractive index as a poly-
v;nyl chloride film).
The values obtained are lis~'ced in the table which
follo~s.
As the examples and comparative examples sho~, the
films according to the invention have surprisingly good
values of 'che roughness (high Rz values)~ mattness ~lo~
gloss values) and contact transparency (low values of the
;nternal cloucliness). The films accord;ng to the invent;on
can easily be printed on or written on and can be employed
for such purposes~ They can furtherMore be employed as a
furnishing film, a film for sealing coffering or a credit
card fil~, and for the product;on of office requisites such
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as document folders.
Example 1
78X by ~eight of Pass-poly~erized polyv;nyl chloride,
K value 5~
10X by weight of mass-polymerized polyvinyL chloride,
K value 75,
12X by ~eight of starch~
ExamP le ?~
75X by ~eight of mass-polymerized polyvinyl chloride,
K value 57,
15% by weight of mass-polymerized polyvinyl chloride,
K value 80,
10% by weight of starch.
Example 3
70X by weight of suspension-polymer;zed polyvinyl chloride,
K value 60,
25X by wei~ht of suspension-polymerized polyvinyl chloride~
K value 70,
5X by ~eight of starch.
Example 4~
93X by ~eight of suspension-polymerized polyvinyl chloride,
K value 65,
5Z by weight of suspension-polymer;zed polyvinyl chloride,
; K value 9D,
2X by ~eight of starch.
Example 5 tCo0parative example analogous to DE OS 2,716,853)
85% by weight of mass-polymerized polyvinyl chloride,
K value 57,
15X by weight of mass-polymerized polyvinyl chlor;de,
K value 80.
Example_6 ~Comparative example)
75X by weight of mass-polymerized polyvinyl chlor;de,
~ value 57,
15% by weight of mass-poly~erized polyv;nyl chlor;de,
K value 80
10X by ~eight of chalk.
Example 7 ~Comparative example)
83X by ~eight of mass-polymerized polyvinyl chloride,
2~
- 10
K value 57,
15X by weight of mass-polymerized polyvinyl chloride,
K value 80,
2% by weight of chalk~
Example 8 tComparative example anaLogous to DE-OS 1,815,891)
80X by weight of mass-polymerized polyvinyl chloride,
K value 57,
15X by weight of mass-polymerized polyvinyl chloride,
K value 80,
10 5% by weight of titaniu~ dioxide.
Table
Example Surface Gloss Contact
(CE = Comparative roughnesstransparency
15 Example) (,um) (%) (%)
1 41 1 15
2 35 3 11
3 ~ 20 5 7
4 19 5 3
2D 5 CE 10 17 2
6 CE 30 8 93
7 CE 20 12 52
8 CE 16 15 1DO
