U.S. patent number 3,811,923 [Application Number 05/192,899] was granted by the patent office on 1974-05-21 for fiber fleece containing a polymeric reinforcing material.
This patent grant is currently assigned to Kalle Aktiengesellschaft. Invention is credited to Klaus-Dieter Hammer, Ludwig Klenk, Herbert Porrmann.
United States Patent |
3,811,923 |
Hammer , et al. |
May 21, 1974 |
FIBER FLEECE CONTAINING A POLYMERIC REINFORCING MATERIAL
Abstract
This invention relates to a fiber fleece based on synthetic
fibers and containing a polymeric organic reinforcing material, and
having, at a proportion of polymeric elastic reinforcing material
of at least 10 per cent by weight and not more than 80 per cent by
weight, calculated on the total weight of a base fleece having a
density between 0.1 and 0.28 g/cm.sup.3, a tensile strength of at
least 0.01 kg/mm.sup.2, a tear propagation resistance of at least 7
kg/mm (according to IUP 8), and a tensile stress or not more than
0.03 kg/mm.sup.2, measured in a tensile elongation test at an
elongation of 10 per cent.
Inventors: |
Hammer; Klaus-Dieter (Finthen,
DT), Porrmann; Herbert (Niedernhausen, DT),
Klenk; Ludwig (Hallgarten, DT) |
Assignee: |
Kalle Aktiengesellschaft
(Wiesbaden-Biebrick, DT)
|
Family
ID: |
25760002 |
Appl.
No.: |
05/192,899 |
Filed: |
October 27, 1971 |
Foreign Application Priority Data
|
|
|
|
|
Oct 30, 1970 [DT] |
|
|
2053497 |
Oct 30, 1970 [DT] |
|
|
2053442 |
|
Current U.S.
Class: |
428/91;
264/DIG.16; 428/96; 428/392; 264/DIG.19; 427/246; 428/391;
428/904 |
Current CPC
Class: |
D04H
1/435 (20130101); D04H 1/645 (20130101); D04H
1/488 (20130101); D06N 3/0002 (20130101); D04H
1/4334 (20130101); D06N 3/10 (20130101); D04H
1/43835 (20200501); D04H 1/4382 (20130101); D04H
1/50 (20130101); D06M 15/423 (20130101); D06M
15/564 (20130101); D06M 15/6436 (20130101); Y10T
428/2964 (20150115); Y10S 264/16 (20130101); Y10T
428/2962 (20150115); Y10S 428/904 (20130101); Y10T
428/23986 (20150401); Y10S 264/19 (20130101); Y10T
428/2395 (20150401) |
Current International
Class: |
D06M
15/564 (20060101); D06M 15/423 (20060101); D06N
3/10 (20060101); D04H 1/64 (20060101); D06M
15/643 (20060101); D06M 15/37 (20060101); D06N
3/00 (20060101); B32b 027/02 (); B44d 001/14 () |
Field of
Search: |
;117/76T,14A,138.8N,138.8F,138.8A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Husack; Ralph
Attorney, Agent or Firm: Bryan, Esquire; James E.
Claims
1. A fiber fleece having a tensile strength of at least 0.01
kg/mm.sup.2 ; having a tear propogation resistance of at least 7
kg/mm.sup.2, according to IUB8; having a tensile stress of not more
than 0.03 kg/mm.sup.2, measured in a tensile elongation test at an
elongation of 10 per cent; comprising, a base fleece, at least half
of whose fibers are synthetic fibers and having a density of 0.1 to
0.28 g/cm.sup.3, a coating of a synthetic material impregnating
said fibers of said base fleece to form a wash-proof union
therewith, in an amount of about 5 to 15 per cent by weight based
on the total weight of said base fleece, and a coherent structure
of a polymeric elastic organic material surrounding and in contact
with the coated fibers of said base fleece, in an amount of about
30 to 65 per cent by weight based on said total weight of said base
fleece; and substantially free of physical cohesion between
contacting surfaces of said coated fibers of said base fleece and
said coherent
2. A fleece according to claim 1 in which the polymeric elastic
organic
3. A fleece according to claim 1 in which the polymeric elastic
organic
4. A fleece according to claim 1 in which the polymeric elastic
organic
5. A fleece according to claim 1 in which the polymeric elastic
organic
6. A octadecyl ethylene according to claim 1 in which the coating
is
7. A fleece according to claim 1 in which the coating is
dimethyl
8. A fleece according to claim 1 in which the coating is a
cross-linkable
9. A fleece according to claim 1 in which the fibers are a 1 : 1
mixture of
10. A fleece according to claim 1 in which the coating is a
condensed melamine/formaldehyde precondensate cross-linked with the
aliphatic side
11. A fleece according to claim 1 in which the coating is a
condensed urea/formaldehyde precondensate cross-linked with the
aliphatic side chains of a polymer having perfluorinated aliphatic
side chains.
Description
The present invention relates to a fiber fleece which contains a
polymeric elastic reinforcing material. Further, the invention
relates to a process for the production of such fiber fleece.
Furthermore, the present invention is concerned with the use of a
fleece of this type as an intermediate product for the manufacture
of a leather substitute, the leather substitute being produced by
applying a microporous covering layer of plastic material,
preferably of polyurethane, to the fleece.
Fiber fleeces are known in which the fibers are bonded by means of
an adhesive. Fleeces bonded in this manner have the desired high
tensile strength, but they are stiff and, therefore, cannot be used
for application purposes where a soft feel of the material or the
formation of textile-like folds are a prerequisite, or where it is
required that the material have the suppleness of leather.
Other known fiber fleeces contain elastomers as binders, so as to
avoid the drawbacks of the above described fleeces. Fleeces whose
fibers are bonded by means of elastomers incorporated therein are
elastic, but they have the disadvantage of being of rubber-like
character, and are thus less suitable as a base material for
processing into a leather substitute.
None of the known fiber fleeces has the foldability and drapability
of textile materials, or possesses the soft feel and flexibility
resembling those of natural leather.
The present invention provides a fiber fleece which does not have
the drawbacks of the known, chemically bonded fiber fleeces and
which, because of its physical characteristics, its drapability and
its flexibility, is suitable as a base material for processing into
air-permeable multilayer materials from which shoe uppers,
garments, upholstery materials, and fancy leather articles can be
manufactured.
Further, the invention is concerned with a process for the
production of such fleece.
The fiber fleece of the invention contains an organic polymer
reinforcing material and, at a proportion of reinforcing material
of at least 10 per cent by weight and at the most 80 per cent by
weight, based on the total weight of a base fleece having a density
in the range from 0.1 to 0.28 g/cm.sup.3, the fiber fleece has a
tensile strength of at least 0.01 kg/mm.sup.2, a tear propagation
resistance of at least 7 kg/mm, and a tensile stress of not more
than 0.03 kg/mm.sup.2, measured at an elongation of 10 per cent in
a tensile elongation test.
Further, the invention is concerned with the use of the fleece
according to the invention as a base material for the manufacture
of airpermeable synthetic material of leather-like characteristics,
in sheet form, for the manufacture of garments, shoes, upholstery
materials, and fancy leather articles. The particular
characteristics of the fleece according to the invention are a
result of its physical parameters, and the parameters are caused by
the particular structure of the fleece. In the fleece, the
individual fibers are coated with a synthetic material whose
adhesion to the fiber surface is such that it cannot be washed
away, whereas it has no adhesion, or substantially no adhesion,
towards the organic elastic polymeric reinforcing material adjacent
to it, which permeates the fleece and surrounds the individual
fibers of the fleece.
In the process for the production of the above-described fiber
fleece - which at a proportion of polymeric elastic reinforcing
material of at least 10 per cent and at the most 80 per cent by
weight, based on the total weight of a base fleece with a density
in the range from 0.1 to 0.28 g/cm.sup.3, has a tensile strength of
at least 0.01 kg/mm.sup.2, a tear propagation resistance of at
least 7 kg/mm (measured by IUP 8), and a tensile stress of not more
than 0.03 kg/mm.sup.2, measured at an elongation of 10 per cent in
a tensile elongation test - in a first process step, a liquid
solution or dispersion of a synthetic substance capable of forming
a coating on the fibers is caused to act upon the fleece; heat
sufficient for evaporation of the solvent or dispersing agent and
for the formation of a wash-proof coating of the substance on the
fibers is then caused to act upon the fleece; the impregnated
fleece is then treated with a liquid solution or dispersion of a
polymeric elastic reinforcing agent; the polymer is then coagulated
in known manner, and the fleece is finally dried.
In another modification of the above described process, which is
within the scope of the present invention and is even preferred, an
impregnating liquid containing liquid halogenated hydrocarbons,
benzene compounds with free phenolic OH groups as swelling agents
for the fibers, and a coating substance for the fibers of the
fleece, which contains esters of higher fatty acids and polyhydric
aliphatic alcohols or of multi-valent aliphatic carboxylic acids
and long-chain aliphatic alcohols, in which liquid the proportion
of chemical coating substance exceeds that of the swelling agent,
i.e., the benzene compound with the free phenolic groups, or both
components are present in equal quantities, is caused to act upon
the fleece in the first process step; the fleece is then freed from
excess impregnating liquid by rinsing with a solvent and then
heated for a period of time ranging from 30 seconds to 10 minutes
to a temperature between 100.degree. and 180.degree. C.; a liquid
solution or dispersion of a polymeric elastic reinforcing material
is then caused to act upon the impregnated material; the polymeric
reinforcing material is then coagulated in known manner; and the
fleece is then dried by heating it for a period ranging from 2 to
30 minutes to temperatures between 100.degree. and 180.degree.
C.
According to the present invention, the above-described preferred
modification of the process may be further varied, in a
particularly advantageous manner, in that an impregnating liquid is
caused to act upon the fleece in which the proportion of swelling
agent exceeds that of the coating substance, the fleece is then
rinsed in order to free it from excess impregnating liquid, dried
at room temperature, and then further treated as described
above.
This particularly advantageous embodiment of the invention may be
further modified in that, after impregnation and removal of excess
impregnating liquid, the fleece is subjected for 30 seconds to 10
minutes to a heat treatment at temperatures ranging from
100.degree. to 180.degree. C., and that the process is then
completed as described above.
Suitable fleeces which may be used as base materials for performing
the process of the invention are matted fiber fleeces based on
synthetic fibers. They consist either exclusively of synthetic
fibers, or half of their fibers are synthetic fibers and the other
half are natural fibers, or they are predominantly composed of
synthetic fibers and contain only a small proportion of natural
fibers. Advantageously, the fleeces are densified by needling, a
needling rate of 200 to 600 stitches per cm.sup.2 being preferred.
The synthetic fibers contained in such fleeces may be of
polyacrylonitrile, of polyamide, or of polypropylene, and in
particular of fibers of such materials which are capable of
longitudinal shrinkage under the influence of heat. Polyethylene
terephthalate fibers having this characteristic are particularly
advantageous.
Suitable mixed fiber fleeces are those which contain from 75 to 50
per cent by weight of polyester fibers and 25 to 50 per cent by
weight of chemically different synthetic fibers, for example
polyamide fibers, polyacrylonitrile fibers, or polypropylene
fibers, a mixing ratio of 1 : 1 between polyester fibers and
chemically, different fibers being preferred. Further, fibers may
be used which consist of polyester fibers in the proportion stated
above, and natural fibers.
Suitable natural fibers are fibers of wool or other animal hair, as
also cotton, hemp, jute, sisal or flax fibers.
The synthetic fibers have a thickness of 0.8 to 3.5 dtex,
preferably between 1.2 and 1.7 dtex.
The base fleece has a density in the range from 0.1 g/cm.sup.3 to
0.28 g/cm.sup.3, preferably from 0.14 to 0.2 g/cm.sup.3. The
expression "base fleece" means a needled fleece containing neither
a coating substance nor a reinforcing material.
The needled fleeces have a weight per unit area in the range from
50 to 400 g/m.sup.2, preferably in the range from 100 to 250
g/m.sup.2.
Suitable reinforcing materials are elastic polymers, such as
synthetic rubber, polyacrylates, especially elastomers, and most
advantageously butadiene-acrylonitrile-methacrylic acid copolymers,
and polyurethane. Natural rubber also may be used as a reinforcing
material.
Elastic polymers are those polymers which show a plastic-elastic
solidification behavior similar to that of rubber within a
temperature range between -20 C. and +50.degree. C. The expression
"elastomers" means the polymers listed on page 154 of "Textbook of
Polymer Chemistry," New York, 1957 (Bielmeyer).
The reinforcing material is introduced into the fleece in the form
of a liquid solution or dispersion of an elastic polymer, for
example by impregnating the fleece with the liquid. Suitable
solvents or dispersing agents for the polymer reinforcing material
are only those which do not dissolve or swell the fibers of the
fleece.
The following solvents may be used for the preparation of a liquid
solution of the polymeric elastic reinforcing material: dimethyl
formamide, dimethyl sulfoxide, and, in the case of polyurethane,
tetrahydrofuran. Water may be used as a dispersing agent for
synethetic rubber or acrylate dispersions.
The solution or dispersion of the high-polymer elastic reinforcing
material has a solids content in the range of 10 to 70 per cent by
weight.
The density of the fleece is determined by the IUP 5 method.
The fleece according to the invention contains a proportion of
reinforcing material of 10 to 80 per cent by weight, based on the
total weight of the fleece, the preferred range being from 30 to 65
per cent by weight.
The fleece according to the invention which contains a polymeric
elastic reinforcing material has a weight per unit per area in the
range of 60 to 600 g/m.sup.2, preferably in the range from 200 to
600 g/m.sup.2.
The liquid which contains the synthetic coating substance and is
applied to the fleece during the first process step, will be
designated in the following as the "impregnating liquid."
The expression "synthetic coating substances" includes those
chemical substances which are capable of forming on the surface of
the fibers a coating which, after sufficient heat action upon the
fibers coated with the substance, forms a wash-proof union with the
fiber surface, due to the good adhesion between the fiber surface
and the coating caused by heat action.
Examples of suitable coating substances, which may be applied in
the form of solutions or dispersions in solvents or dispersing
agents which do not swell the fibers of the fleece, are the
following: ethylene ureas of the following general formula
##SPC1##
wherein
R is an aliphatic chain with 14 to 22 carbon atoms.
Fatty amines with a carbon chain of 16 to 18 carbon atoms,
paraffins, etherified fat-modified synthetic resins having side
chains with 12 to 18 carbon atoms, cross-linkable and
non-cross-linkable silicones, such as dimethyl polysiloxane and
hydrogen-methyl-polysiloxane, or cross-linkable polymeric compounds
suitable for textile finishing treatments, which have
perfluorinated aliphatic side chains (e.g. "Scotchgard," a product
of Minnesota Mining and Manufacturing Co., St. Paul, Minn.,), also
may be used. Cross-linkable polymers which are suitable have
perfluorinated aliphatic side chains containing from 6 to 14,
preferably from eight to 12 carbon atoms.
In a cross-linkable polymer containing carboxyl groups, e.g., the
perfluorinated cross-linkable aliphatic side chain may be attached
to the carboxyl group of the polymer via a sulfonamide group.
A fleece whose fibers have been impregnated with one of these
coating substances will be designated in the following as the
"impregnated fleece."
The fleece contains from 2 to 20 per cent by weight, preferably
from 5 to 15 per cent by weight, based on the weight of the
impregnated fleece, of a synthetic coating substance of the
above-mentioned chemical structure which is capable of forming a
wash-proof coating on the surface of the fibers.
The coating substance must have the inherent characteristic that
there is no cohesion, or substantially no physical cohesion,
between adjoining surfaces of the coating and of the reinforcing
material, i.e., that the cohesion between these two surfaces is
only such that a sliding displacement of the surfaces relative to
each other is possible under the action of external mechanical
forces upon the fleece, for example when the fleece is bent or
stretched.
According to one modification of the inventive process, the coating
substance is incorporated in the fleece in the form of a liquid
solution or dispersion, for example by immersing the fleece in the
liquid and then evaporating the solvent or dispersing agent, e.g.
by causing sufficient heat to act upon the fleece. A bath ratio in
the range of 1 : 10 to 1 : 50, preferably of 1 : 10 to 1 : 30, is
most advantageous. For the preparation of a solution containing the
coating substance, those solvents are preferred as do not dissolve
or swell the fibers of the fleece, e.g. water.
Suitable dispersing agents for the preparation of the liquid
dispersion of a coating substance are those which do not dissolve
the fibers of the fleece, for example water.
The proportion of coating substance in the impregnating liquid used
in the first process step is in the range from 2 to 30 per cent by
weight, based on the total weight of the liquid, a range of 6 to 12
per cent by weight being preferred.
When the process is performed according to a further preferred
embodiment, the impregnating liquid contains liquid halogenated
aliphatic hydrocarbons, benzene compounds with free phenolic OH
groups, and esters of higher molecular weight fatty acids and
polyhydric aliphatic alcohlics, or of multi-valent aliphatic
carboxylic acids and long-chain aliphatic alcohols.
The liquid halogenated, preferably chlorinated, aliphatic
hydrocarbons may be saturated or unsaturated. Suitable saturated
chlorinated aliphatic hydrocarbons are, e.g., 1,1,1-trichloroethane
and carbon tetrachloride. Liquid chlorinated unsaturated aliphatic
hydrocarbons are preferred, however, in particular
trichloroethylene and, above all, perchloroethylene. Mixtures of
these hydrocarbons also may be employed.
The above-mentioned liquid halogenated hydrocarbons also may be
used as solvents, for rinsing the impregnated fleece.
Benzene compounds with free phenolic OH groups which are
particularly suitable are, e.g., p-cresol, o-cresol, oxybenzoic
acid, and salicylic acid methyl ester; phenol is preferred.
Mixtures of these components may also be employed, for example a
mixture of the preferred phenol with salicylic acid methyl
ester.
The benzene compound with a free phenolic OH group, which is
contained in the impregnating liquid, acts as a swelling agent for
the fibers of the fleece.
As a further component, the impregnating liquid contains a chemical
substance in the form of an ester, which is capable of forming a
coating upon the fibers. The esters may be of higher molecular
weight fatty acids and polyhydric aliphatic alcohols, in which case
the fatty acid components of the ester may be unsaturated, but is
preferably saturated. Alternatively, the esters may be of
multi-valent aliphatic carboxylic acids and long-chain monovalent
aliphatic alcohols. In this case, the aliphatic alcohols preferably
are saturated, but also may be unsaturated. Mixtures of these
esters also may be used.
The following chemicals are particularly suitable for forming a
coating upon the fibers according to the preferred embodiment of
the process: citric acid monostearyl ester, glycol-dioleate, but
more preferably the glycol-monooleate, glycerol-disterate, and more
preferably the glycerol-monostearate, erythritol-dipalmitate, and
in particular erythritol-monopalmitate, sorbitol-monostearate, and
sorbitol-distearate. Of these preferred coating substances,
glycerol-monostearate can be used with particular advantage.
In the impregnating liquid according to the preferred embodiment of
the invention, either the swelling agent, i.e., the benzene
compound with the free phenolic OH group, is present in excess, or
the chemical coating substance for the fibers, i.e., the
above-mentioned esters, or the two components are contained in the
impregnating liquid in equal quantities.
When the chemical coating substance is contained in the
impregnating liquid in excess over the swelling agent, or when the
two components are present in the impregnating liquid in equal
quantities, the impregnated fleece is subjected for a period of 30
seconds to 10 minutes to a temperature between 100.degree. and
180.degree. C., after excess impregnating liquid has been removed
by rinsing.
When the component of swelling agent exceeds that of the chemical
coating substance in the impregnating liquid, the impregnated
fleece is rinsed with a solvent and then dried at room temperature.
Subsequently, the impregnated fleece obtained by one of these
processes is soaked in a solution or dispersion of an elastomeric
reinforcing material, the elastomer is coagulated, and the fleece
is subjected for a period ranging from 2 to 30 minutes to a
temperature between 100.degree. and 180.degree. C.
That modification of the process within the scope of the preferred
embodiment, in which an impregnating liquid is used in which the
quantity of the swelling agent for the fibers exceeds that of the
coating substance for the fibers, yields particularly advantageous
results as regards the easy displaceability of the fibers relative
to the elastic reinforcing material surrounding them within the
fleece. However, this modification requires a larger technical
expenditure when performed on a commercial scale than does the
other modification of the present process, in which an impregnating
liquid is used wherein the substance used for coating the fibers is
in excess of or equal to the swelling agent. This latter
modification of the inventive process also yields chemically conded
fleeces which are excellently suited as base materials for the
manufacture of synthetic leather, due to their very good
fiber-binder separation, and are superior to known fleeces on
account of their good qualities.
When using an impregnating liquid in which the chemical coating
substance in the form of the ester component exceeds the quantity
of the swelling agent component in the form of the benzene compound
with a free phenolic OH group, or in which swelling agent and
coating substance are present in equal quantities, wash-proof
anchoring of the coating substance to the fibers of the fleece is
effected by the heat-treatment from 30 seconds to 10 minutes at
temperatures in the range from 100.degree. to 180.degree. C., which
takes place after the fleece has been impregnated.
The effect of the fiber-binder separation may be considerably
increased by using an impregnating liquid in which the quantity of
swelling agent exceeds that of the coating substance, in which case
de-swelling of the fibers of the fleece takes place only after the
binder has been incorporated in the fleece, viz. during the drying
process, while heat in the range of 100.degree. to 180.degree. C.
is caused to act for a period of 2 to 30 minutes upon the fleece.
By the de-swelling of the fibers, the crossection of the swollen
fibers is reduced. The coating substance disposed on the fibers and
the reduction of the cross-section of the fibers which takes place
after incorporation of the binder are responsible for the
particularly easy relative displaceability between the fibers and
the elastic reinforcing material surrounding them.
The coating substance is regarded as bonded to the fiber surfaces
in a wash-proof manner, when the adhesion between the fiber surface
and the coating substance is such that no separation, or
substantially no separation, of the coating substance from the
fiber surface can be observed when the material is mechanically
washed 5 times at a temperature of 60.degree. C. in accordance with
DIN method No. 54010.
The following washing liquid is suitable : 5 grams of soap and 2
grams of calcined sodium carbonate per liter of fluid; washing time
30 minutes at 60.degree. C.; bath ratio 1 : 50.
After its incorporation in to the fleece, e.g., by precipitating
the polymer is known manner from the polymer solution or
dispersion, the polymeric reinforcing material is contained in the
fleece not in the form of a plurality of discrete polymer
particles, but instead forms a coherent structure by which the
pores of the fleece are more or less filled, depending upon the
quantity of reinforcing material employed. The fibers are totally
or partially sourrounded by the reinforcing material. It is an
essential feature of the present invention that between the surface
of the fibers and the surface of the polymer reinforcing material
surrounding them there is the coating substance which, on the one
hand, adheres so firmly to the fiber surface that it cannot be
washed off, while, on the other hand, there is no cohesion, or
substantially no cohesion, between the surface of the coating
substance and the surface of the polymer reinforcing material
adjoining it, so that a parallel displacement of the two surfaces
relative to each other is possible. In known fleeces bonded by
polymeric binders, the binder permeates the fleece in a similar
manner as in the fleece according to the invention, but the
adhesive power between the surface of the fibers and the adjoining
surface of the polymeric binder is so strong in known fleeces of
this type that it is impossible to displace the fiber surface
relative to the surface of the polymer binder surrounding it.
However, in the case of the fleece according to the invention, such
displacement is possible due to its particular structure. This
particular structure is responsible for the particularly
advantageous physical data and the favorable qualities of the
fleece according to the invention, which render it suitable for the
purposes mentioned above.
In the following, the production of a fleece according to the
invention will be described:
A needled matted fiber fleece consisting of polyester fibers is
treated with a liquid solution or dispersion of a coating
substance, for example by immersing the fleece in a bath consisting
of the liquid and then removing excess liquid, e.g. by squeezing.
For the soaking process, a bath ratio of 1 : 20 is of particular
advantage. The fleece is then subjected for 2 to 20 minutes to a
heat treatment at temperatures in the range from 100 to 180.degree.
C.
By this heat treatment, any dispersing agent or solvent present in
the fleece is driven off, and on the other hand the heat action
causes a wash-proof anchoring of the coating substance to the
surface of the fibers. Heating of the fleece is performed in known
manner, for example by using a tenter drier.
Subsequently, a liquid containing the high molecular weight
polymeric elastic reinforcing material in dissolved or dispersed
form is incorporated in known manner in the impregnated fleece.
This may be effected, e.g., in an impregnating bath. The
impregnating liquid has a solids content ranging from 10 to 70 per
cent by weight, preferably from 30 to 50 per cent by weight of
reinforcing material, calculated on the total weight of the liquid.
The polymeric reinforcing material is then coagulated in the
fleece. Coagulation may be caused, in known manner, by treatment of
the impregnated fleece with a coagulating liquid which is miscible
with the solvent or dispersing agent, but does not dissolve the
polymeric reinforcing material.
water may be used as a liquid coagulating agent, especially when
the reinforcing material is dissolved in an organic, water-miscible
solvent. When an aqueous dispersion of the reinforcing material is
used, coagulation of the polymeric reinforcing material is caused,
in known manner, by heat action.
After coagulation of the polymer reinforcing material, the fleece
is substantially freed from the solvent or dispersing agent used
for the polymer, e.g. by causing heat in the range of 100.degree.
to 180.degree. C. to act upon the fleece until it is sufficiently
dry. This heat treatment may take place, for example, in a drying
cabinet or a tenter drier.
In the following, the method of producing a fleece by the above
mentioned preferred modification is described:
A needled matted fiber fleece consisting of polyester fibers is
treated with an impregnating liquid in which the quantity of
chemical coating substance, i.e., the ester component, exceeds that
of the swelling agent, i.e., the benzene compounds with free
phenolic OH groups, or in which both components are present in
equal quantities, for example by immersing the fleece in a bath
containing the impregnating liquid. The fleece is then removed from
the impregnating bath and freed from excess impregnating liquid by
thoroughly rinsing it in a solvent bath.
for the impregnating process, a bath ratio of 1 : 20 is
particularly advantageous. After impregnation and rinsing, the
fleece is subjected for a period ranging from 10 seconds to 10
minutes to a heat treatment at temperatures ranging from
100.degree. to 180.degree. C.
In the course of this heat treatment, the volatile components of
the impregnating liquid left between and in the fibers of the
fleece are evaporated, and, on the other hand, the heat action
causes a washproof anchoring of the coating substance to the
surface of the fibers.
Subsequently, a liquid containing the polymeric elastic reinforcing
material is dissolved or dispersed form is incorporated in known
manner in the impregnated fleece, e.g., by means of an impregnating
bath.
The impregnating liquid has a solids content in the range of 20 to
70 per cent by weight, preferably from 30 to 50 per cent by weight,
of reinforcing material, based on the total weight of the liquid.
The polymeric reinforcing material is then coagulated in the
fleece. Coagulation may be caused in known manner, e.g., by
treating the impregnated fleece with a coagulating agent which is
miscible with the solvent or dispersing agent, but does not
dissolve the polymeric reinforcing material.
Water is particularly suitable as a coagulating agent when the
reinforcing material is dissolved in a water-miscible organic
solvent. When an aqueous dispersion of the reinforcing material is
used, the polymeric reinforcing matterial is coagulated in known
manner by heat action, e.g. at temperatures in the range of
38.degree. to 45.degree. c.
After coagulation of the polymeric reinforcing material in the
fleece, the fleece is substantially freed from the solvent or
dispersing agent for the polymer, for example by heating it for 2
to 30 minutes to temperatures between 100.degree. and 180.degree.
C. until it is sufficiently dry.
A drying cabinet or a tenter drier may be used for this heat
treatment.
According to a particularly advantageous variation of the preferred
modification of the process, an impregnating liquid is used in
which the quantity of swelling agent exceeds that of the coating
substance. In this case, the impregnated fleece is freed from
excess impregnating liquid in the above described manner, dried at
room temperature, and then the elastic polymeric reinforcing
material is incorporated therein as described above.
After coagulation of the plastic polymeric reinforcing material by
heat action, the fleece is subjected for a period from 2 to 30
minutes to heat action at temperatures between 100.degree. and
180.degree. C. Advantageously, this heat treatment takes place in a
drying cabinet or a tenter drier supplied with hot air. With an
impregnating liquid of the above described composition, the fibers
are de-swollen by the heat treatment, i.e., the solvent and the
swelling agent are removed from the fibers and their cross-section
is reduced, thus separating the surfaces of the fibers from the
polymeric reinforcing materal surrounding them. At the same time, a
wash-proof anchoring of the coating substance to the fiber surfaces
is effected. These two effects combine in a particularly
advantageous manner to provide the displaceability of the fibers
relative to the elastic reinforcing material surrounding them.
The last-mentioned modification of the inventive process may be
further modified in that, after impregnation of the fleece and
removal of excess impregnating liquid, the fleece is subjected to a
heat treatment for 10 seconds to 10 minutes, at temperatures of
100.degree. to 180.degree. C., and then further processed as
described.
The invention will be further illustrated by reference to the
accompaying drawing which shows the reinforced fleece of the
present invention in cross-section.
In the drawing, numeral 1 denotes a fiber, numeral 2 denotes the
surface of a fiber carrying a coating of synthetic material, and
numeral 3 denotes the porous elastic polymeric reinforcing
material.
EXAMPLE 1
A matted fiber fleece having a density of 0.14 g/cm.sup.3 and
consisting of 50 per cent by weight of polyester fibers capable of
length reduction under heat influence and 50 per cent by weight of
polyamide fibers (staple length of the fibers 30 mm, thickness of
the fibers 1.3 dtex) is soaked in a liquid containing 70 g of a 22
per cent aqueous dispersion of octadecyl ethylene urea ("Primenit"
LD, a product of Farbwerke Hoechst AG., Frankfurt-Hochst, Germany)
per liter of water. The bath ratio is 1 : 20. The fleece is then
squeezed off, dried for 10 minutes in a tenter drier by the action
of heat at 110.degree. C., and finally treated for 2 minutes at
140.degree. C. in the tenter drier, thus causing a cross-linking of
the coating substance on the surface of the fibers. The thus
impregnated fleece is then soaked in known manner in a 50 per cent
by weight aqueous dispersion of a
butadiene/acrylonitrile/methacrylic acid terpolymer ("Perbunan" N
3405 M, a product of Farbenfabriken Bayer, Leverkusen, Germany),
squeezed off, and then coagulated in known manner by heat action
and dried for 20 minutes in a drying cabinet at 150.degree. C. The
fleece has a tear propagation resistance of 7 kg/mm (by IUP 8) and
is very flexible. During tearing, a sliding of the elastomer from
the fibers can be observed.
Proportion of elastomer: 58 per cent by weight.
The fleece produced in this manner may be used as a substrate for
synthetic leather of the box sides type.
EXAMPLE 2
A fiber fleece according to Example 1 is soaked in a bath
consisting of an 8 per cent by weight aqueous dispersion of
dimethyl polysiloxane ("Primenit" SW, a product of Farbwerke
Hoechst A.G., Frankfurt-Hocchst, Germany) and then squeezed of. The
fleece is dried for 7 minutes by the action of warm air at
120.degree. C. and then treated for 30 seconds with air at a
temperature of 150.degree. C. in a tenter drier. The softening
characteristics imparted by this silicone treatment exceed the
water-repellent properties. In the ensuing soaking process, the
fleece is impregnated with a 50 per cent by weight aqueous
dispersion of a butadiene-actylonitrile-methacrylic acid terpolymer
("Perbunan" N 3405 M) which also contains 2.5 per cent by weight of
titanium dioxide, and is then squeezed off. The fleece is then
heated in a tenter drier, thus causing a coagulation of the polymer
in the fleece. Very flexible fleeces having a tear propagation
resistance between 8 and 10 kg/mm (by IUP 8) are thus obtained. The
fleece produced in this manner is particularly suitable for use as
a substrate from which synthetic leather is prepared which is
comparable to leather of the box sides type in its mechanical
properties. The elastomer content of the fleece is about 62 per
cent by weight, based on the total weight of the fleece.
EXAMPLE 3
A fiber fleece corresponding to that used in Example 1 is
impregnated with a liquid which contains, per liter of water, 70 g
of cross-linkable hydrogen methyl polysiloxane (e.g. "Arkophob" SN,
a product of Farbwerke Hoechst A. G., Frankfurt-Hoechst, Germany)
and 7 g of zirconium oxychloride as a catalyst (bath ratio 1 : 20),
then squeezed off, dried for 8 minutes at 120.degree. C., and then
treated for 3 minutes at a temperature of 150.degree. C. in a
tenter drier. By this treatment, the methyl polysiloxane disposed
on the surface of the fibers is caused to cross-link. The fleece is
then impregnated in known manner with a 50 per cent aqueous
dispersion of a butadiene/acrylonitrile/methacrylic acid terpolymer
("Perbunan" N 3405 M) containing 2.5 parts by weight of titanium
dioxide (calculated on the solids content), and then coagulated by
heating to 38 to 40.degree.C. A substantially complete separation
of the elastomer from the fibers is thus achieved, which results in
a tear propagation resistance of the fleece of 9 kg/mm (by IUP 8)
and high flexibility.
fleeces produced in this manner may be used as a base material for
the production of a leather substitute of the box sides type.
The elastomer content of the fleece is about 61 per cent by weight,
and its elasticity resembles that of natural box sides leather.
EXAMPLE 4a
A fiber fleece corresponding to that used in Example 1 is
impregnated in a 30 per cent by weight aqueous dispersion of a
corss-linkable polymer containing perfluorinated aliphatic side
chains (so-called "Scotchgard" compounds, for example "Oleophobol"
FC 218, a product of Chemische Fabrik Pfersee GmbH., Augsburg,
Germany). The bath ratio is 1 : 20.
The thus impregnated fleece is squeezed off and then dried for 3
minutes at 120.degree.C.
Subsequently, it is exposed for 2 minutes to a temperature of
150.degree.C in a tenter drier, so that cross-linking of the
polymer occurs.
Advantageously, the fleece is treated with a dilute solution of a
wetting agent (e.g. "Marlon" A, a product of Chemische Werke Huls
A.G., Marl, Germany) before it is impregnated with a reinforcing
material, thoroughly squeezed, and then soaked, while wet, with a
50 per cent aqueous disperion of a
butadiene/acrylonitrile/methacrylic acid terpolymer ("Perbunan" N
3405 M)containing 2.5 parts by weight of titanium dioxide, based on
the solids content. In this manner, a completely uniform
impregnation of the fleece is achieved. Due to the water and oil
repellent qualities of the finished fleece, a separation of the
elastomer from the fibers is achieved which yields tear propagation
resistance values between 8 and 10 kg/mm (by IUP 8). The fleece may
be used as a support for processing into a flexible leather
substitute resembling a relatively coarse leather of the box sides
type.
EXAMPLE 4b
A particularly uniform coverage of the fiber surface with the
coating substance is achieved when using a cross-linkable polymer
having perfluorinated aliphatic side chains, in combination with a
polymer based on a melamine/formaldehyde precondensate (e.g.
"Arkofix" NM, a product of Farbwerke Hoechst A.G.,
Frankfurt-Hochst, Germany).
A fiber fleece of the type used in Example 1 is impregnated with a
finishing bath containing 100 g. of "Arkofix" NM, 10 g of magnesium
chloride CMgCl.sub.2) and 30 g of a cross-linkable polymer with
perfluorinated aliphatic side chains (for example "Oleophobol" FC
218) per liter of water.
The fleece is squeezed off and dried for 3 minutes at 120.degree.C.
Then it is exposed for 2 minutes to a temperature of 150.degree.C
in a tenter drier, whereupon the precondensate condenses and enters
into a cross-linking reaction with the cross-linkable polymer
having the aliphatic side chains.
EXAMPLE 5
A fiber fleece such as the one used in Example 1 is impregnated
with a liquid containing, per liter of water, 80 g of an
urea/formaldehyde precondensate ("Arkofix" NHL, a product of
Farbwerke Hoechst A.G., Frankfurt-Hochst, Germany), 30 g of a
product based on a cross-linkable polymer with perfluorinated
aliphatic side chains (e.g. "Oleophobol" P 68, a product of
Chemische Fabrik Pfersee, Augsburg, Germany), and 8 g of ammonium
chloride.
The thus impregnated fleece is then squeezed off, dried for 5
minutes at 120.degree.c, and then subjected for 2 minutes to a
temperature of 150.degree.C in a tenter drier, so that the
urea/formaldehyde precondenstae completes its condensation reaction
and undergoes a cross-linking reaction with the cross-linkable
polymer with perfluorinated side chains. The fleeces thus produced
have very marked water- and oil-repellent qualities. Therefore, the
impregnated fleece is advantageously first soaked in a solution of
a wetting agent (e.g. "Marlon"A), thoroughly squeezed off, and then
impregnated in the wet state with a 50 per cent aqueous dispersion
of a butadiene/acrylonitrile/methacrylic acid terpolymer
("Perbunan" NT dispersion, a product of Farbenfabriken Bayer,
Leverkusen, Germany) containing 2.5 per cent (based on the solids
content) of titanium dioxide as a filler. The fleece is again
squeezed off, then coagulated at a temperature of 40.degree.C,
washed, and finally dried at 150.degree.C in a tenter drier.
The fleeces thus produced may be used as base materials for the
production of a leather substitute which corresponds in its
mechanical properties to leather of the box calf type. The tear
propagation resistance values are around 8-9 kg/mm. The elastomer
content of the fleece is 61 per cent, calculated on the total
weight of the fleece.
EXAMPLE 6
A fiber fleece according to Example 1 is pretreated as described in
Example 3 but instead of being impregnated with an elastomer
dispersion as in Example 3 and then coagulated and so on, it is
impregnated with a polyurethane solution ("Caprolan" a product of
Lemforder Kunststoff GmbH., Lemforde, Germany), coagulated with
water, and so on. Thus, in the present example, the material is
pretreated with an aqueous dispersion and bonded with a
polyurethane solution.
EXAMPLE 7
A matted fiber fleece consisting of 50 per cent by weight of
polyester fibers capable of shrinking under heat influence and 50
per cent by weight of polyamide fibers (staple length 30 mm, titer
1.3 dtex) and having a density of 0.1 g/cm.sup.3 is impregnated
with an aqueous dispersion containing 80 g of dimethyl polysiloxane
("Primenit" SW) per liter of water (bath ratio 1 : 30), then
squeezed off, dried for 5 minutes at 120.degree.C, and then treated
for 2 minutes at 150.degree.C in a tenter drier. Subsequently, the
fleece is impregnated with a 50 per cent by weight aqueous
dispersion of a butadiene/acrylonitrile/methacrylic acid terpolymer
("Perbunan" N 3405 M) having a solids content of 50 per cent, and
the elastomer is then coagulated in known manner by heat action and
dried at 150.degree.C.
A very flexible fleece is thus produced which has a binder content
of 65 percent and possesses a tear propagation resistance of 7
kg/mm (by IUP 8).
EXAMPLE 8
A matted fiber fleece consisting of 50 per cent by weight of
polyester fibers capable of length reduction under heat influence
and 50 per cent by weight of polyamide fibers (staple length 30 mm,
titer 1.3 dtex) and having a density of 0.26 g/cm.sup.3 is
impregnated with an aqueous dispersion containing 80 g of hydrogen
methyl polysiloxane ("Arkophob" SN) and 8 g of zirconium
oxychloride as a catalyst per liter of water. The bath ratio is 1 :
30. The fleece is then squeezed out and dried for 5 minutes at
120.degree.C. Subsequently, a stream of air heated to 150.degree.C
is caused to act for 3 minutes upon the fleece. The fleece
pretreated in this manner is impregnated in known manner with an
aqueous dispersion of a butadiene/acrylonitrile/methacrylic acid
terpolymer ("Perbunan" N 3405 M, solids content 50 per cent) and
the elastomer is then coagulated by heat action.
A complete separation of the elastomer from the fibers is thus
achieved, and a tear propagation resistance of 15 kg/mm (by IUP 8).
The binder content is about 54 per cent. The fleece thus produced
may be used as a substrate for the production of synthetic leather
of the box calf type.
EXAMPLE 9
A matted fiber fleece consisting of 50 per cent by weight of
heat-shrinkable polyester fibers and 50 per cent by weight of
polyamide fibers, which has fibers of a staple length of 30 mm and
a titer of 1.3 dtex, a weight per unit area of 250 g/m.sup.2, and a
density of 0.14 g/cm.sup.3 and has been needled at a rate of 400
stitches per cm.sup.2, is treated for 10 minutes, at room
temperature, in a container filled with an impregnating liquid
containing 30 g of phenol and 50 g of glycerol monostearate per
liter of perchloroethylene. The bath ratio is 1 : 30. The fleece is
then removed from the bath and rinsed in another bath filled with
pure perchloroethylene, removed from this bath, and finally dried
for 30 seconds at 120.degree.C in a tenter drier. Subsequently, the
fleece is impregnated in a trough containing a 50 per cent aqueous
dispersion of a butadiene/acrylonitrile/methacrylic acid terpolymer
("Perbunan" N 3405 M), and the polymer is coagulated by heating the
fleece to 38.degree. to 40.degree.C. The fleece treated in this
manner is then dried for 15 minutes at 160.degree.C in a drying
cabinet. The tear propagation resistance (by IUP 8) of the material
is 7 kg/mm. (For comparison: Fleeces bonded in the normal manner
have tear propagation resistance values between 4 and 5 kg/mm.)
During tearing, a sliding of the elastomer from the fibers can be
observed, other than in the case of a normal elastomer bonding
where a breaking of the fibers can be observed.
The fleece produced in this manner is suitable for use as a base
material for synthetic leather of the box sides type.
EXAMPLE 10
The procedure described in Example 9 is repeated, except that the
impregnating liquid applied to the fiber fleece during the first
step of the process contains 10 g of phenol and 20 g of glycerol
monostearate per liter of perchloroethylene.
EXAMPLE 11
The procedure described in Example 9 is repeated, except that the
impregnating liquid contains 15 g of phenol and 30 g of glycerol
monostearate per liter of perchloroethylene.
EXAMPLE 12
The procedure described in Example 9 is repeated, except that the
impregnating liquid contains 40 g of phenol and 60 g of glycerol
monostearate per liter of perchloroethylene.
EXAMPLE 13
A fiber fleece as described in Example 9 is treated in the manner
described in said example with an impregnating liquid containing 30
g of phenol and 10 g of glycerol monostearate per liter of
perchloroethylene. After a treatment of 10 minutes, the fleece is
rinsed in pure perchloroethylene and then dried at room temperature
in the open air. The fleece shows a considerable increase in
weight, by up to more than 20 per cent by weight as compared with
the untreated fleece, which is caused by a considerable swelling of
the fibers. The cross-section of the polyamide fibers is extended
by swelling, whereas the polyester fibers absorb the swelling agent
or solvent without extending their cross-section. When kept at room
temperature, the fibers remain swollen for a relatively long period
of time.
The fleece treated as described above is impregnated in known
manner with an aqueous dispersion of a
butadiene/acrylonitrile/methacrylic acid terpolymer ("Perbunan" N
3405 M), then squeezed off to remove excess impregnating liquid,
coagulated by heat treatment at 38.degree. to 40.degree.C, washed,
and finally dried for 5 minutes at 160.degree.C. During the drying
process, the fibers are de-swollen, i.e., the swelling agents and
solvents are evaporated from the fibers. The bonded fleeces thus
produced are very flexible and their rolling and bending behavior
resembles that of leather. The proportion of elastomer is about 60
per cent by weight, based on the total weight of the fleece. The
resistance to tear propagation (measured according to IUP 8) is 8
kg/mm (box calf).
EXAMPLE 14
The procedure described in Example 13 is repeated, except that the
impregnating liquid used in the first process step contains 40 g of
phenol and 15 g of glycerol monostearate per liter of
perchloroethylene.
EXAMPLE 15
The procedure described in Example 13 is repeated, except that the
impregnating liquid contains 50 g of phenol and 20 g of glycerol
monostearate per liter of perchloroethylene.
EXAMPLE 16
The procedure described in Example 13 is repeated, except that the
impregnating liquid contains 60 g of phenol and 30 g of glycerol
monostearate per liter of perchloroethylene.
By varying the proportions of the components in the impregnating
liquid, the sliding properties of the fibers with respect to the
binder are varied.
EXAMPLE 17
A matted fiber fleece as described in Example 9 is treated for 10
minutes in a liquid containing 50 g of phenol and 30 g of citric
acid monostearate per liter of perchloroethylene.
Thereafter, it is rinsed with pure perchloroethylene and treated
for 3 minutes with hot air of 150.degree.C in a tenter drier. The
thus pretreated fleece is then impregnated in known manner with a
50 per cent by weight aqueous dispersion of a
butadiene/acrylonitrile/methacrylic acid terpolymer ("Perbunan" N
3405 M), coagulated, and dried for 15 minutes at 160.degree. C in a
tenter drier.
A supple fleece is thus produced which has a tear propagation
resistance of 7 kg/mm (measured according to IUP 8) and may be used
as a substrate for the production of synthetic leather of the box
sides type.
EXAMPLE 18
A matted fiber fleece of the type described in Example 9 is treated
for 8 minutes in a trough filled with an impregnating liquid which
contains 30 g of phenol and 50 g of glycol monooleate per liter of
perchloroethylene. Subsequently, the fleece is washed in pure
perchloroethylene and exposed for 5 minutes to a temperature of
150.degree.C in a tenter drier. The fleece is then impregnated with
a 50 per cent by weight aqueous dispersion of a
butadiene/acrylonitrile/methacrylic acid terpolymer ("Perbunan" N
3405 M), squeezed off, coagulated by heat action at 38.degree. to
40.degree.C, and dried for 15 minutes at 160.degree.C.
The tear propagation resistance of the fleece thus produced is
around 7 kg/mm (measured according to IUP 8).
It will be obvious to those skilled in the art that many
modifications may be made within the scope of the present invention
without departing from the spirit thereof, and the invention
includes all such modifications.
* * * * *