Note: Descriptions are shown in the official language in which they were submitted.
~2~7~33
A MIXTURE OF FIRES FOR THE REINFORCEMENT OF CONSTRUCTION
MATERIALS, SPECIFICALLY FOR THE REINFORCEMENT OF HYDRAULIC
BINDING AGENTS, A METHOD OF REINFORCING CONSTRUCTION
MATERIALS 7 AND FORMED ARTICLES OF SAID MIXTURE
BACKGROUND OF THE INVENTION
nun a I EVE ,rlcN
The present invention relates to a mixture ox fires for the
production of fire reinforced Construction materials, such
as e.g. hydraulically setting materials, specifically of a
cementitious material having reinforcing fires in form of
polyacrylni-trlle fires and polyvinyl alcohol fires. The in-
mention relates further to a method of reinforcing sunk con-
struction materials by such mixtures of fires which set after
the molding thereof.
The polyacrylnitrile fires will be referred to throughout
this specification as PAN-fibres and the polyvinyl alcohol
fires will be referred to as PVA-fibres.
2. DESCRIPTION OF THE PRIOR ART
The leasability of producing shaped articles such as puffins,
corrugated plates pipes or garden articles in various forms
prom hydrous suspensions comprising e.g. asbestos and cement
by means of dehydrating machines, echoic mechanizer by
means ox injection methods is generally known. Such articles
were able to secure a dominant position among construction
material during the past decennials In the course of the
recent years it has increasingly become obvious that the most
important raw material or the production of these products,
namely asbestos, will soon no longer be available for such
utilization due to various reasons, such as availability,
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development of costs as well as due to health considerations.
It is not only the known excellent service properties of
asbestos cement which are based on the unique combination of
properties inherent in asbestos fires, said properties form
additionally the basis of the Hatscheck-dehydrating methods
which are known world wide
All of the above circumstances have caused in the recent years
an intensive research activity having as object the finding
of replacement fires which can completely replace the as-
bests in the known manufacturing processes of the dodder-
tying methods. It has, however, been discovered extremely soon
that not one kind of fires would be found which incorporated
all positive properties of asbestos.
Following properties characterize asbestos as excellent pro-
diction process as well as reinforcement fires:
- large specific surface
- excellent dispersive power
- outstanding chemical festivity
- high concrete retention capability
- excellent capability of forming nonwovens
- high breaking strength
high modulus of elasticity
- small elongation at fracture
Asbestos displays as process expedient means an excellent
dispersive power in an hydraulic cement suspension. Due to its
high filtration capability and its affinity to cement asbestos
is in to position to retain the binding agent forming in the
cement during the dehydrating process step,
The high breaking strength combined with the high modulus of
elasticity and the small elongation at fracture have a post-
live effect on the hydrated final article which can bestow
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the a~bestos-cement products the known high bending
strength.
Because neither natural nor synthetical fires having the
combination of properties of asbestos could be found, search
efforts for finding possible replacement products lead to the
realization that commensurate with the two main functions of
asbestos mixtures of fires must be made use of in order to
be able to carry out a production utilizing such new fires
on existing machines and apparatuses (see e.g. DEEPS
30 02 484 of Amounts). The filtration properties of asbestos
can be simulated in the fire mixtures by additions of cell-
lose and/or synthetic fib rides. Regarding the reinforcing
properties reinforcing fires are made use of. Such fires
may be organic or inorganic high modulus flares which are
added usually in a cut length of 4-12 millimeters.
There hardly exists a synthetic fire which has not been
tested regarding such application as cement reinforcing
cement. Most of these fires did, however, not succeed due
to a large variety ox reasons, such as insufficient chemical
resistivity, bad affinity to cement, unsatisfactory mechanical
properties or due to the exceedingly high price. Among the
entire available fires only two types of synthetic fires
which meet the demands of a cement reinforcing fire were
able to prevail. One of these fires has been developed on
the basis of polyacrylnitrile and has been marketed for in-
stance by the Hoechst Company (Western Germany under the
trademark "Nolan 10"~ The other fiber is formed on -the
basis of polyvinyl alcohol and is e.g. available from the
Queerer C. Japan under the trademark "Kuralon" (DEEPS 28 50
337~. The most important properties of these fires are
tabulated in table 1.
Table 1
Textllemechanical proper-ties of types of fires suitable as
reinforcement of cement:
_ _
Type of fire breaking elongation modulus of
strength at fracture elasticity
cN/dtex % cN/dtex
Polyacrylnitril,
PAN (e.g. * 690 - 8,5 10 - 16 mint 130
"Nolan 10")
Polyvinyl alcohol,
PEA 10 - 15 5,5 - 15 min. 175
(ego "Kuralon~') l _ .
The comparison of -the textile-mechanical properties between
the PVA-fibres and the PAN-fibres reveals that the PVA-fibres
display -the better mechanical properties. If now fire cut-
tongs having a length of 6 millimeters of both types are
distributes in an hydraulic cement suspension and worked on a
filter press to fire cement plates, the measured strength
values of such plates reveal that the better properties of the
fires can also bestow the final product with better strength
properties (table 2).
Table 2
Strength properties of plates of fibre-cement, produced on a
filter press, of port land cement and the high modulus fires
on the basis of PEA and PAN.
_ .
fires bending energy of density absorption
strength fracture of water
wit,% N/mm2 kJ/m2 g/ccm
fires
__
1,0 12,5 0,203 ~,982 15,0
1,5 14,7 0,457 19920 14,5
' _ 16,0 0,701 1~851 15~7
fires
1,0 14,8 0,652 1,935 14,6
1,5 16,1 1,208 1,900 15,1
2,0 19,5 1,835 1,863 16,0
. ................................. .. _ .
Jo - * Trade mark
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Textile mechanical properties of the fires used.
_ Breaking Modulus of Elongation Titer
strain elasticity at fracture
cN/dtex cN/d-tex _ _ dtex
PAN 7,5 150 11 to
PEA 12 240 _ __ _ _
The energy of fracture incorporates an extremely important
material technological property. It gives evidence of the
brittleness or impact tensile strength, rest. of a product.
This can have such effect in a practical application that e.g.
when placing of roof covering plates having differing values
of an energy of fracture, but identical bending strengths,
some plates may break suddenly without prints when sub-
jacketed to a loading by a roofer (brittleness), however, in
the second case may take the loading up by a larger bending.
The analysis of the results reveals that in comparison with
the PAN-fibres the PVA-fibres having the better textile-
mechanical properties can not only bestow the fibre-cement
plates with a higher bending strength, but that their energy
of fracture is larger, too. In these tests, the energy of
fracture is defined as the surface area under the strain-elon-
gallon curve up to the point where the maximal bending
strength is reached, i.e. the plate has ruptured (fig. 1).
By knowledge of the relationship between -the data of the
fires and -the product proper-ties ox the fibre-cement plates
resulting these from it would be an easy task to produce fire-
cement products exposed to high demands regarding bending
strength and energy of fracture exclusively by utilizing PEA-
fires. However, -the high costs of PVA-fibres counteract this
solution. Due -to the high costs of the raw material combined
with an extremely intrinsic fire production process, the costs
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of producing PVA-fibres are 50 - 100 % higher than those of
PAN-fibres.
Considering additionally that the present prices of asbestos
amount to a fraction only of the prices of synthetic fires
it is quite obvious that a decisive importance must be given
to the price of the fires to allow the production of market
table fire cement products at all. Accordingly, it would be
a highly desirable object for the fibre-cement industry to
provide a fire having the properties of the PVA-fibres desk
cried above which, however, is economically acceptable, i.e.
not substantially more expensive than the PAN-fibre.
According to the rules of mixtures for fire reinforced come
pound construction materials it should be expected that in
Gaze of reducing ire mixtures the strength properties or
energy of rupture, rest. resulting in the reinforced material
follow linearly and proportionally the mixing ratio (see
"Fiber-Reinforced Cement Composites", Technical Report 51.067,
The Concrete Society, Terminal House, Grosvenor Gardens,
London 1973 and H. Crinkly "Fiber Reinforcement", Akademisk
Foreleg, Copenhagen, 1964).
SUMMARY OF TOE INVENTION
Hence, it is an object of the invention to provide a fire no-
enforcement mixture in which cheap PAN-fibres are substituted
for a large amount of PVA-fibres without suffering a loss of
the positive properties in the fibre-cement product.
A further object is to provide a mixture of fires for the
production of fibre-reinforced concrete comprising PEA- and
PAN-fibres and having as little as possible, at least, how-
ever, 10 % PVA-fibres.
I
- pa -
Therefore the present invention relates to a
mixture of polyacrilnitrile and polyvinyl alcohol fires as
reinforcing fires for materials setting after the molding
thereof, specifically for hydraulically setting materials,
said mixture of fires comprising about 50-90% polyacrilni-
trite fires and about SUE polyvinylalcoho e
.,~.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
I.. _ ..__ . . . ... . .. _ _ _
The mixtures of fires realized by the present invention will
be explained now based on following testing examples made in
the praxis.
Suitable fires for the production of the decrease-mixtures
of PAN- with PVA-fibres are polyacrylnitrile fires having a
high modulus, a modulus of elasticity of at least 130 cN/dtex,
an elongation at fracture of maximal 16 % and a breaking
strength of a-t least 6 cN/dtex~
Suitable polyvinyl alcohol fires are high modulus fires ha-
vying following specifications:
Modulus of elasticity ox at least 175 cN/dtex, elongation at
fracture of maximal 15 % and a breaking strength of at least
10 cN/dtex.
Both kinds of fires can be used with uniform titers or as
mixtures of fires of differing titers. Preferred use is made
of fires in the range of 0.5 - 5.0 dtex. The fires can be
cut either to exact, uniform lengths or when be ground or
mixed in various lengths, Preferred is the application of the
PVA-fibres in lengths of 4 - 15 mm and the PAN-fibres in
lengths of 2 - 12 mm.
The hollowing examples will disclose that it is specifically
advantageous if the PVA-fibres used are larger than the ad-
mixed fires by about 1/3.
Possible production methods for structural members or articles,
in which the fire mixtures according to the invention are
used are e.g. dehydrating method by sitting drum machines or
fourdriniers, however also mono-extrusion machines, injection
apparatuses or filter-presses.
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-- 8 --
Mixtures which are suitable for a production on above macho-
noes comprise in a hydrous suspension apart of the inventive
fire mixtures also a binding agent, such as e.g. cement and
possibly additional fibrous materials having filtering pro-
parties as well as a variety of filling materials or additives.
Suitable binding agents are hydraulic inorganic binding agents
such as cement, gypsum earth alkaline silicates or earthalka-
line ailments However, organic binding agents such as e.g.
synthetic resins may be used too. Suitable filling materials
or additives are e.g. quartz sand, blast-furnace slag, fly
ash, pu~zolane, mica, rock dust. Suitable auxiliary fires
operative to retain the binding agents and additives on the
screens may be cellulose fires in form of sulfate cellulose,
wood shavings, thermomechanical pulp and/or synthetic fib rides
on the basis of plastic materials, e.g. polyethylene. The
retention capability can be improved additionally by the use
of flocculation agents, e.g. on -the basis of polyacrylamides.
Products which can be produced with those mixtures on the de-
hydrating machines are e.g. planar plates, corrugates plates
or boards, tubes or shaped articles,e.g. garden articles.
The inventive PVA/PAN-fibre mixtures will now be explained
based on a number of exemplar applications.
The tests were made on a sifting drum dehydrating machine of
the Hatschek design.
The fibre-cement-suspensions were prepared in a separate put-
per and comprised a solids content of 80 g/l and continuously
pumped from the pulper into the material chamber of a Hatschek-
machine.
Shortly before entering into the material chamber, a dosage of
200 Pam of a flocculation agent type polyacrylamide was added
to 3
for improving the retention of the cement. On the machine
plates of about 6 mm were produced by 2Z full notations of
the pattern plate, which plates were pressed between oiled
plates during 60 minutes in a staple press at a specific
pressing pressure of 250 bar to a thickness of 4,8 mm. Of all
variations unpressed specimens were produced and tested, too.
The setting of the fibre-cement plates proceeded in a wetting
room of 100 % relative humidity at 20C. After the plates were
additionally stored for 3 days submerged in water, the tests
were made in a wet or damp, rest. condition.
by xtu s used
For the production on filter press:
Port land cement (2800 Elaine) 100 parts
fire mixtures 2.0 parts
For the production according to the
Hatschek method:
Port land cement (2800 Elaine) 100 parts
Old waste paper (45 SO) 3.5 parts
Polyethylenefibride ~"Pulpex"E~A,
Hercules USA) 2.0 parts
fire mixtures 2.0 parts
Following variants were used as fire mixtures:
PAN 2 1,7 1,3 1~0 0,7 parts
PEA 0 0,3 0.7 1,0 I 2,0 parts
The textile-mechanical proper-ties of the fires were:
- PAN
Titer 1,5 dtex, breaking strength 7,2 cN/dtex, modulus of
elasticity 140 cN/dtex, elongation at fracture 9 %
- PEA
Titer 2 dtex, breaking strength 12,5 cN/dtex, modulus of
elasticity 250 oN/dtex, elongation at fracture 6,5 %
*Trade mark
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;. -
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- 10 -
PAN and PEA fires were used in a variety of combination of
4 and 6 mm cut lengths.
For the tests on the filter press mixtures were prepared in
water which consisted only of Port land cement and the PVA/PAN-
fires.
The test of the fire cement plates proceeded by aid of a
Wolpert testing apparatus having a three-point bearing con-
tact on plates of 25 x 25 mm. The bearing contact distance
amounted to 167 mm and the test speed to 26 mm/min. The anal
louses of the results were made by aid of a computer connected
to the testing apparatus.
do Results
The results are tabulated in the tables 3 to 7.
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Table 3
Test results ox fire cement plates having variable PVA-PAN-
fire rations, produced on a Ha-tschek-machine.
. ___ .
fire mixture bending energy of Density Absorption
PAN PEA strength fracture of water
6 mm 6 mm
parts parts N/mm2 kJ/m2 g/ccm %
_
press plates
_ 2,0 22,4 3,047 1,941 12,3
0~3 1,7 21,1 2,799 1,934 11,4
0,7 1,3 21,8 2,884 1,943 10,9
1,0 1,0 20,7 2,698 1,928 12,0
1,3 0,7 21,3 2,532 1,919 11,9
1,7 0,3 19,0 2,105 1,932 12,4
2,0 - 1791 1,108 1,911 12,1
-- A. . Jo ._ ______ . ._ _
unpressed
plates __
- 2,0 14,8 4,272 1,555 20,1
0,3 1,7 14,7 3,820 1,567 19,9
0,7 1,3 14,5 4,133 1,557 19,8
1,0 1,0 13,6 3,740 1,539 21,2
1,3 0,7 13,8 4,010 19500 23,7
1,7 0,3 13~1 3,205 1,532 20,8
2,0 - 12,4 1,902 1,514 21,9
._ _.___ e_ _, ,_,,
2 7
- 12 -
Table 4
Test results of fire cement plates having variable PAP
fire rations, produced on a filtering press.
_ .
fire mixture bending energy of density absorption
PAN PEA strength rupture of water
6 mm 6 mm
parts parts _ _ Kim g/ccm %
_ 2,0 14,2 2,603 1,753 19,9
0,3 1,7 14~4 2,512 1,758 19,8
0,7 1,3 13,9 2,543 1,752 1997
1,0 1,0 13,9 2,527 1,754 19,8
1,3 0,7 1397 2,410 1,732 19,9
1,7 0,3 13,1 1,700 1,748 19,6
2,0 - 12,2 0,9'75 1,731 19,8
. ___ . ... _ . _
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- 13 -
Table 5
Test results of fire cement plates having variable
- PVA-PAN-fibre rations, produced on a Hatschek-machine.
__ _ _
fire mixture bending energy of density absorption
PUN PEA strength rupture of water6 mm 4 mm
parts parts N/mm2 Kim g/ccm %
, _ _ _ _
. __
pressed plates
_ 2,0 24,2 3,075 1,93512,6
0,3 1,7 23,1 2,418 199421176
0,7 1,3 20,4 1,990 1,91912,0
1,0 1,0 19,2 2,001 1,92011,6
193 0,7 18S9 1,820 1,92311,2
1~7 0,3 17,5 1,221 1,91711,8
2,0 - 17,1 1,108 1,91112,0
_
unpressed plates
- 2,0 15,0 4,519 1,55022,6
0,3 1,7 14,7 4,059 1,54122,4
0,7 1,3 14,2 3,465 1,52821,9
1,0 1,0 13,4 2,968 1,53620,4
1,3 0,7 13,1 2~436 1,53220,4
197 0,3 12,7 2,150 1~52121,3
2,0 - 12,4 2,100 1,51421,9
. _ _ . _
SKYE
- 14
Table 6
Test results of fire cement plates having variable
PVA-PAN fire rations, produced on a filtering press
ire mixture bending energy of density absorption
PAN PEA strength rupture of water
6mm 4 mm
parts parts N/mm2 kJ/m2 g/ccm
__ _ __
_ 2~0 14,8 2,429 1,807 18,7
0,3 1,7 15,3 2,510 1,823 17,7
0,7 1~3 14,0 2,010 1,779 18,6
1,0 1,0 13.5 1,619 1,785 18,2
1,3 0,7 12,9 1,327 1,761 18,8
1,7 0,3 1295 0,902 1,750 18,7
2,0 12,4 0,945 1,747 18,9
__
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- 15 -
Table 7
Fibre-cement plates produced in accordance with the invention
and having materials PVA-PAN-ratios, produced on a Hatschek-
machine.
.
fire mixture bending energy of density absorption
PAN PEA strength rupture of water
4 mm 6 mm
parts parts N/mm2 Kim g/ccm %
_
Do Do .
_ 2,0 22,6 3 9 331 1,938 12,2
0,3 1,7 22,8 3,115 1,933 12,1
0,7 1,3 22,1 ~101 1,941 11,0
1,0 1~0 22,0 2,987 1,9~1 11,5
1,3 0,7 21,3 2,605 1,929 12,3
1,7 I 18,2 1,980 1,937 12,0
2,0 - 15,3 0,972 1,941 11,1
unpressed plates
_ 2,0 15,1 4,657 1,548 22,3
0,3 1,7 15,2 4,450 1,551 22,0
0,7 1,3 14,8 4,522 1,550 21,9
1,0 1,0 14~8 4,186 1,542 22,6
1,3 0,7 14,1 3,475 1,553 21,9
1,7 0,3 12,9 2,497 1,561 20,7
2,0 - 11,7 1,303 1,568 19,9
Textile-mechanical properties of the fires used in table 7.
Titer 3,0 dtex, breaking strength 7,3 cN/dtex
modulus of elasticity 152 cN/dtex
elongation at rupture 9,8 %
Titer 2,0 dtex, breaking strength 12,5 cN/dtex
modulus of elasticity 250 cN/dtex
elongation at rupture 6,5 I.
While there are shown and described a number of embodiments
of the present invention, it shall be clearly understood that
such are for sake of illustration only and not to be inter-
preyed in a limiting sense
