Note: Descriptions are shown in the official language in which they were submitted.
2 ~ ' 2 ~
O.Z. 0~50/42165
Moldings based on f ibers
The present invention rela~es to moldings based
on fibers (component A), containing
B) from 5 to 25~ by weight, based on A, of a polymer of
b1) from 75 to 99.9% by weight, based on B, of
vinylaromatic monomers, methyl methacrylate,
methyl acrylate, acrylonitrile, methacrylo-
nitrile, vinyl halides, acrylates and meth-
acrylateæ of alcohols of 2 to 12 carbon atom~
and/or vinyl esters of not more than 20 carbon
atoms, where the sum of the acrylates and
methacrylates of alcohols of 2 to 12 carbon
a~oms and of the vinyl esters may be not more
than 20~ by weight, based on B,
b2) from 0.1 to 25% by weight, based on ~, of one
or more monomers of the general formula I
l1 l2 8 l4
CH=C ~ -X-R3-Z IH
R5
where Rl and R2 are each -H or Cl-C4-alkyl, R3 is
a bridge member of 1 to 20 carbon atoms, R4 is
-C(o)R5, -C(O)ORB or -CN, Rs is -H, -C(O)R9,
-C(O)OR9 or -CN, X is -O- or -NR7-, Z is a
single bond, -CE2-, -O-, -NR3- or -O-C(O)- and
R6, R7, R8 and R9 are each -H, alkyl, aryl,
alkaryl or aralkyl of not more than 12 carbon
atoms,
and
b3) from 0 to 10% by weight, based on B) of further
copolymerizable monomers.
Moldings based on mineral fibers are known per
se. For example, DE-A 29 24 085, US-A 4 187 142 and
US-A 4 189 345 describe a process for the production of
fiber boards, in which the additive~ together with the
binder, which may be a precipi~ated binder, are filtered
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on a Fourdrinier wire ~ie. sheet formation) and the fiber
boards are then dried at elevated temperatures.
Ceiling panels are produced in this manner, for
example from kaolin, mineral fibers and starches. The
serious disadvantage of such panels, which are in prin-
ciple very rigid, is that they lose their shape, ie. sag
under their own weight, in humid warm rooms~ ie. the
visual appearance of such sagging ceilings is unattrac-
tive and therefore undesirable. Another disadvantage is
the sensitivity of such sheet-like structures to the
degradation of the binder starch by microorganisms, which
is manifested by dark spots and the loss of mechanical
strength. Such panels can of course be treated with
microcides, for example with formaldehyde depot sub-
stances. By gradually reducing formaldehyde, theseensure protection against attack. However, to ensure
protection over many years, it i8 necessary to choose
relatively high doses of preservatives, which may lead to
odor annoyances or, in certain circumstances, to allergic
reactions of the inhabitants.
EP-A 367 023 discloses fiber boards which contain
acrylate copolymers. These can be used as aqueous
solution. When these binder sy~tems are employed in
practice, it has been found, however, that certain
aspects are still unsatisfactory. For example, in the
production of mineral fiber boards on the Fourdrinier
wire, it ha~ been found that the viscosity of the polymer
solutions is too high for conventional operational
measures, such a~ conveying and meteringO The viscosity
of such polymer solutions which are about 10% s~rength is
about 25 Pa.s. Only solutions having solid contents
substantially below 10% by weight can be readily used on
virtually all units, but this is uneconomical owing to
the large amount of the diluent water. Furthermore, such
polymers tend to migrate during drying of the crude
boards, ie. tend to result in a loss of bindsr in the
interior of the mineral fiber boards, which may have an
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adverse effect on the further processing of the crude
hoards. The skilled worker knows that thiR binder
migration can be counteracted by the use of substances
having inverse solubility, for example polyvinyl methyl
ethers. However, they give rise to additional costs and
` may increase the moisture absorption of the end products.
EP-A 386 579 discloses moldings which are bound
with acrylate dispersions. Overall, the shaped articles
produced with these binders and with those of EP-A 367
023 have satisfactory properties, but their mechanical
strength and their water absorption can still be im-
proved. An increase in the water resistance can be
achieved with a higher dose of agents which impart water
repellency, but it is then necessary to accept a decline
lS in the mechanical strength as well as wetting and ad-
hesion problems in the shaped articles.
DE-A 23 46 310 discloses glass fiber-reinforced
polyamides. About 1% by weight of a copolymer which
predominantly contains butyl acrylate with small amounts
of butanediol monoacrylate acetoacetate is used as a
size. A thermoplas~ic molding material having high
impact strength is obtained in this manner. There is no
reference to fiber boards. However, if such polymers are
nevertheless used for the production of fiber boards,
undesirably high densities are obtained in conjunction
with acceptable stability and an impressibility unaccept-
able for acoustic panels.
According to EP-A 241 127, textile materials can
be bound with aqueous polymer dispersions. These are
copolymers which contain ethyl acrylate and butyl
acrylate as main components, with small amounts of, for
example, acetoacetoxyethyl acrylate. An important aim is
to obtain textiles having high flexibility. The skilled
worker was therefore prevented from considering polymers
of the disclosed type for the production of rigid fiber
boards or fiber moldings.
It is an ob~ect of the present invention to
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provide moldings based on fibers, which avoid the dis-
advantages described above and combine low water absorp-
tion with high rigidity.
We have found that this object is achieved by the
moldings defined at the outset and a process for their
production. The preferred embodiments ara described in
the subclaims.
Suitable fibers are mineral fibers, for example
rockwool, basalt wool, slag wool and glass fibers having
fiber lengths of, in general, from 0.2 to 5 cm, in
particular from 0.5 to 2.5 cm, and thicknesses of from
about 1.7 to 3.3 dtex. Organic fibers are also suitable.
These include primarily wood fibers, such as comminuted
and/or digested wood, such as pinewood. Such wood fibers
are usually produced from wood chips, chopped wood or
sawdust (for example Ullmann's Encyklopadie der tech-
nischen Chemie, 4th Edition, Vol. 12, page 720 et saq.).
Other organic fibers, such as cellulose fibers or fibers
of synthetic polymers, such as polypropylene fibers
and/or polyacrylonitrile fibers, may also be added to the
wood fibers, in general in amounts of 5 to 6Q, preferably
from 15 to 40, in particular from 15 to 25, % by weight,
based on wood fibers. These fibers usually have a length
of from 0.3 to 1.5 cm and a thickness of from 10 to 30
dtex.
The polymer B i~ used in amounts of from 5 to 25,
preferably ~rom 5 to 15, ~ by wei~ht, based on fibers A.
It is preferably composed of from 75 to 96% by weight of
b1, from 2 to 20% by weight of b2 and from 0 to 20% by
weight o~ b3.
Suitable vinylaromatic monomers are those of not
more than 20 carbon atoms, preferably vinyltoluene, ~-
and para-methylstyrene, ~-butylstyrene, 4-n-butylstyrene,
4-n-decylstyrene and particularly preferably styrene.
The vinyl halides are e~hylenically unsaturated compounds
substituted by chlorine, fluorine or bromine, preferably
vinyl chloride or vinylidene chloride.
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5 - O.Z. 0050/42165
Other suitable monomers b, are esters of acrylic
or methacrylic acid with alcohols of 2 to 12 carbon
atoms, preferably alkanols. Examples of alcohols are
methanol, ethanol, n- and isopropanol, n-, sec- and tert-
butanol, n-pentanol, isoamyl alcohol, n-hexanol, cyclo-
; hexanol, octanol, 2-ethylhexanol, lauryl alcohol, benzyl
alcohol and vinylethanol.
Examples of esters of acrylic and methacrylic
acid are hexyl (meth)acrylate, lauryl (meth)acrylate,
cyclohexyl acrylate, phenylethyl methacrylate, methyl
acrylate, ethyl acrylate, n-, sec- and tert-butyl (meth)-
acrylate, benzyl methacrylate, cyclohexyl methacrylate,
methyl methacrylate, ethyl methacrylate and especially
2-ethylhexyl acrylate and n-butyl acrylate.
15Vinyl esters of not more than 20 carbon atoms
are, for example, vinyl acetate, vinyl propionate, vinyl
laurate and vinyl stearate.
In the general formula I of b2, the following
sub~tituents are preferred: Rl is H, R2 is H or methyl,
R3 is an aliphatic or aromatic bridge member, such as
-CH2-, -C2H4-, -C4H8- and furthermore -C3H6- or -C8H16-, R4 is
-C(O)R6, such as acetyl, benzoyl or -CN, R5 is -H or
-C(O)R9, such as benzoyl or acetyl, X is -O- or -NH-, Z is
-oc(o)- or a ~ingle bond, and R6 and R9 are each methyl,
ethyl or phenyl.
Acetoacetoxyethyl acrylate and methacrylate
IR R R
CH 2=C--C~ ( CH 2 ) 2~C--CH 2--C--CH 3
acetoacetoxybutyl acrylate and methacrylate
CH 2=C--C~ ( CH 2 ) 4{)--C--CH 2--C--CH 3,
and cyanoacetoxyethyl methacrylate and cyanoacetoxyethyl
acrylate
CH~C-C-O-C2H4-O-C-CH2-CN ,
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where R in each case is H or CH3, are preferred.
Such compounds are known per se from
DE-A 17 93 660, US-A 4 088 499 or EP-A 241 127 and can be
prepared in a conventional manner by reacting a
hydroxyalkyl ester, for example the hydroxyethyl ester of
acrylic or methacrylic acid, with diketene or cyanoacetyl
chloride.
Good results are also obtained with 1,1-
dibenzoyl-2-mathacrylamidoethane, 1,1-dibenzoyl-2-acryl-
amidoethane
o
R O
CH2-c-c-NH-cH2--CH O
\11~
l-benzoyl-l-acetyl-2-methacrylamidoethane and l-benzoyl-
l-acetyl-2-acrylamidoethane
I R
CH2=C--C--NH-CH2--CH O
C-CH3
where R is H or CH3.
Such compounds are known per se from
DE-A 38 19 455 and can be prepared in a conventional
manner by amidomethylation of 1,3-diketone3 in the
presence of strong acids.
b3 are, for example, acrylic acid, methacrylic
acid, acrylamide, methacrylamide, maleic acid, fumaric
acid, itaconic acid, maleic anhydride, butanediol mono-
acrylate, glycidyl methacrylate or diunsaturated mono-
mers, such as di~inylbenzene, butan~diol diacrylate,
diallyl phthalate, butadiene or chloroprene. Acrylic
acid and methacrylic acid are preferred and are generally
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used in amounts of from 1 to 8% by weight, based on B.
Good results are obtained with polymers of
; b1) a mixture of from 55 to 90% by weight, based on B,
of a vinylaromatic monomer, from 2 to 25% by weight,
s based on B, of one or more monomers selected from
the group consisting of methyl acrylate, acrylo-
nitrile and methacrylonitrile and from 0 to 20,
preferably from 5 to 20, % by weight, based on B, of
` acrylates and/or methacrylates of alcohols of 2 to
12 carbon atoms,
b2) from 2 to 15% by weight, based on B, of a monomer of
the general formula I,
and
b3) ~rom 0 to 10% by weight of further copolymerizable
monomers,
and with polymers of
bl) a mixture of from 55 to 96, preferably not more than
95, ~ by weight, based on B, of methyl methacrylate,
from 0 to 35% by weigh~ of one or more monomers
selected from the group consisting of methyl
acrylate, acryloni~rile and methacrylonitrile and
from 0 to 20, preferably from 1 to 20, % by weight,
based on B, of acrylates and/or methacrylates of
alcohols of 2 to 12 carbon atoms,
b2) from 4 to 20~ by weight of a monomer of the general
formula I
and
b3) from 0 to 10, preferably 0, ~ by weight, based on B,
of further copolymerizable monomers.
The polymer B is preferably prepared by free
radical emulsion polymerization in the aqueous phase.
Batch processes or feed processe~ in which the
initiator and/or the monomers, which may be emulsified in
water, are fed in a little at a time or continuously
during the polymerization, may be used (cf. for example
Encyclopaedia of Polymer Science and Engineering, Vol. 6
(1986), 1 to 52). The agueous copolymer dispersions
2~6
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,:
formed generally have a copolymer concentration, ie. a
solids content, of from 40 to 60, in many cases from 45
to 5S, % by weight. From 0.2 to 3~ by weight, based on
the monomers used, of anionic and/or nonionic
S emulsifiers, for example sodium dialkylsulfosuccinates,
sodium salts of sulfated oils, sodium salts of
alkylsulfonic acids, sodium, potassium and ammonium
alkylsulfates, alkali metal salts of sulfonic acids,
fatty acids, fatty alcohols, fatty amides and
alkylphenols, ethoxylated and/or sulfated derivatives
thereof, as well as sodium salts of fatty acids, such as
sodium stearate and sodium oleate, and sulfonated alkyl
diphenyl ethers, are generally used as emulsifiers.
The pH of the polymer dispersions is from 3 to 9,
preferably from 4 to 8.5. The polymer dispersions
generally have a low viscosity, ie. from about 10 to 20
mPa.s at 23C, and a shear gradient of ~80 s-1. The
median particle size is from lO0 to 300 ~m, preferably
from 100 up to 200 ~m (d5~ value, ultracentrifuge, W.
Maechtle, Nakromolekulare Chemie 185 (1984), 1025).
Good results are obtained if the polymer B has a
glass transition temperature of from 60 to 150C, prefer-
ably from 70 to 100C, in particular from 70 to 95C.
The low residual monomer content of the polymers
used according to the invention, which is generally less
than 500 ppm, based on the dispersion, i3 advantageous
for processing. This means that the concentration of
working substance in ~he air at the workplace is extreme-
ly low and that th~ finished articles are virtually
odorless.
The polymer dispersions are stable to shear
forces and can be transported without problems and
conveyed by means of suitable pumps. Nevertheles~, they
have very advantageous precipitation behavior. They
coagulate with the circulation or process water en-
countered in mineral fiber works wi~hout further addi-
tives, so that the addition of precipitating agents,
2~9B26
; - 9 - O.Z. 0050/42165
eg. aluminum sulfate, can advantageously be dispensed
with. However, in the production of shaped wood
articles, it may sometimes be advantageous to promote the
coagulation of the polymer dispersions by small doses of,
for example, dilute aqueous aluminum sulfate solutions.
The novel moldings may contain nonfibrous fillers
C in addition to the components A and B. These may be
fire-dried sands, finely divided clays, such as kaolin or
montmorrilonite, feldspar, chalk, kieselguhr and mica,
which are preferably used with the mineral fibers. Their
amounts may be from 20 to 80, preferably from 30 to 60,
% by weight, based on the fibers used.
The moldings may additionally contain not more
than 10, preferably from 1 to 3, % by weight, based on
fibers, of conventional fireproofing agents, such as
aluminum silicate and aluminum hydroxide, borates, such
as sodium tetraborate, and/or phosphates, such as primary
sodium phosphate.
Not more than 5, preferably from l to 2, % by
weight, based on the fibers, of conventional water
repellant agents, such as silicones and/or wa~es, are
sometimes added during the production of the moldings.
It is also possible to add starch, such as corn
starch or potato starch, generally in amounts of from 1
to 5% by weight, based on the fibers.
Rnown flocculants, such as polyacrylamides, may
also be present in small amounts.
The moldings can be produced by various methods.
An aqueous suspension can be prepared, for
example, from fibers A, if required the fillers C and
further additives with thorough mixing. The polymer B,
as an aqueous dispersion, is advantageously added at the
same time or afterward. The process is carried out in
general at room temperature, ie. at from 15 to 35C. The
suspension is then generally flocculated by adding a
flocculant. The resulting mixture is introduced into a
mold and dewatered, which may be effected, for example,
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.
by suction and/or pressing. The still wet molding is
usually dried in the course of from 0.1 to 5 hours at
from 100 to 250C. Dryiny ovens, circulating-air dryers,
` IR lamps or microwave emitters and/or heatable presses
may be used.
Other production methods are also possible. For
example, in the production of sheet-like structures,
sheet formation can be carried out on a Fourdrinier wire
and drying can be effected at elevated temperatures (from
about 70 to 150C). It is also possible to carry out a
molding process after sheet formation before effecting
drying at elevated temperatures. Furthermore, all
additives can be mixed in the dry or moist state, and
mixing may be effected in a fluidized bed. Thereafter,
the mixture is molded and the molding is dried, prefer
ably at elevated temperatures.
Other production proce~ses which have proved
suitable in practice in many cases comprise moistening of
the fibers and any further additives by spraying or
immersion, followed by squeezing off and subsequent
drying at elevated temperatures, and it is possible to
adjust the densities of such sheet-like structures during
the drying process by pressing to a greater or lesser
extent.
Furthermore, it is pos~ible first to convert
fibers and, if required, precipitating agents and addi-
tives into a molding, which is then impregnated with an
aqueous dispersion of the polymer B. ~his process is
described in EP-~ 386 579.
The base moldings are advantageously first
impregnated with the aqueous dispersion, all-round
impregnation being preferred, and are dried and then
coated with the pigmented dispersion for decoration.
In order to obtain coatings having an attractive
appearance, it is advantageous to carry out the total
coating procedure in a plurality of operations and to dry
the particulax layer applied between the individual
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~ o.Z~ 0050/42165
-
opera~ions, genexally at from lO0 to 180C. The process
can be particularly advantageously used for the
production of sound~insulating panels having improved
dimensional stability in the presence of atmospheric
humidity, and the sheet-like base moldings can, if
required, be provided with sound-absorbing structures.
The novel materials may be applied by spraying, roller-
coating or pouring, the surface of the base molding
generally being ground beforehand. The amounts applied
are in general from 2 to 100 g~m2 (calculated in amounts
M of the anhydrous copolymer present in the coating
material or impregnating material).
The novel, generally concrete-free moldings are
in particular boards, ie. square elements, usually having
a width/length ratio of from 1 : l to 1 : 5 and a height/
length ratio of from 1 : 10 to 1 : 100.
Examples are mineral fiber boards or wood fiber
boards, which may be used as ceiling panel~ or sound-
insulating panels. The visible surface of the panels may
be provided with known sound-absorbing structures and, in
a conventional manner, with decorative coatings. The
sound-insulating (ceiling) panels obtained in this manner
have very good insulating behavior, are very rigid, even
in the moist s~ate, and readily release the absorbed
moisture again.
Surprisingly, the disadvantages described above
are avoided in the novel moldings. Although the polymers
B are thermoplastics, as components of the moldings they
perform all binding functions of the thermosetting
plastics, such as rigidity. Also surprising is the fact
that these hydrophilic polymers ensure that the moldings
are rigid also in a humid and warm atmosphere and even if
a limited amount of starch is present in the shaped
articles. Another positive factor is that the polymers
can be readily prepared by emulsion polymerization.
Treatment of the moldings with biocide~ or fungicides can
be dispensed with since the polymers are not degxaded
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;under the conditions of production and use of the boards.
Nevertheless, the disposal of binder residues and also of
the moldings produced therewi~h presents no problems.
The polymers foxm water-insoluble compounds with poly-
valent ions, eg. calcium ions, magnesium ions or Fe(III)
ions, or are precipi~ated by these and thus cannot enter
the groundwater. The calcium compounds are very highly
adsorbed onto the solid particles in waste water
treatment plants. Polymers which are composed only of
carbon, hydrogen and oxygen have particular ad~antages in
this respect.
In the examples which follow, parts and per-
centages are by weight, unless stated otherwise.
The investigations of the boards produced by way
of example were carried out by the following methods:
Density of the mineral fiber boards
Test specimens having the dimensions 250 mm x 50
mm are cu~ out. The thickness is determined with a
calliper gage and is used for calculating the volume.
The density is calculated in g/cm3, as a mean value of 2
test specimens.
Density of the wood fiber boards
Circular test specimens with D = 9 mm are punched
out by means of a punch. The thickne~s is measured with
a calliper gage and is used to calculate the volume, and
the density is calculated in g/cm3 as the mean value of 3
test specimens.
Water absorption
Test specimens having the dimensions 250 mm x 50
mm are stored under water at room temperature under a
load for 1 hour or 2 hours. After removing excess liquid
by dabbing off, the weight increase is determined by
weighing as the mean value of 2 test specimens in each
case, as a percentage of the weight increase.
Dimensional stability ~measure of the rigidity)
Test specimens measuring 250 mm x S0 mm are
ground by means of a belt grinder until ~hey are 15 mm
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- 13 - O.Z. 0050/42165
thick. The side facing away from the wire during sheet
formation is ground.
The test specimens thus obtained are placed flat
in an atmosphere of 38C and 95% relative humidity,
horizontally close to the end edges and loaded with a
1 kg weight in the middle, so that the load acts on the
total length of the test specimen. The sag of the test
specimen is measured after the load has been removed and
an indication of the long-term behavior of mineral fiber
boards is thus obtained.
Strength
The dried test specimens (dimensions 17 cm x 2 cm
x 2 cm) are placed close to the end edges and are
subjected in the middle to a continuously increasing
force, so that the load acts on the total length of the
test specimen. The force applied at fracture is stated
as the mean value of five test specimens, in kg/cm2.
Breaking force
The breaking force i5 determined according to DIN
53,455.
The following abbreviations are used:
AAEM Acetoacetoxyethyl methacrylate
AN Acrylonitrile
AA Acrylic acid
EHA 2-Ethylhexyl acrylate
MMA Methyl methacrylate
MA Methyl acryla~e
MAA Methacrylic acid
n-BA n-Butyl acrylate
S Styrene
The polymer dispersions B used as binders in the
examples were prepared according to the following gen~ral
method:
The dispersions were prepared by aqueous free
radical emulsion polymarization from the monomers, which
had been emulsified with the aid o the emulsi~iers in
half the water employed for preparationl usin~ 0.5% by
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- 14 - o.z. 0050/42165
weight, based on the monomers, of sodium peroxodisulfate
as an initiator in the form of a 2.5% strength by weight
aqueous solution at 80C. For thiq purpose, half t~e
water employed for preparation was initially taken and
10% by weight of the initiator solution were added while
stirring at the polymerization temperature. Thereafter,
the monomer emulsion was fed continuously into the
polymerization vessel in the course of~2 hours and the
initiator solution in the course of 2.5 hours, while
stirring. For post-polymerization, stirring was con-
tinued for a further 2 hours at the polymerization
temperature and working up was then carried out in a
known manner. The amount of wa~er employed for the
preparation was such that the stated solids contents were
obtained.
The fatty acid salts stated in Examples 3, 4, 5,
7 to 13 and Vl as emulsifiers were prepared in situ by
neutralizing the corresponding carboxylic acids with
sodium hydroxide solution. The monomer emulsions were
prepared by adding the monomers and, if required, water
or the other emulsifiers. In these examples, further-
more, one third of the water employed for preparation was
initially taken and two thirds were used for the monomer
emulsion. Otherwise, the procedure was as described
above.
The glass transition temperatures T8 were deter-
mined by differential thermal analy~i~ (DTA) according to
ASTM D 3418-82 tmidpoint temperature).
EXAMPLE 1
Binder: 42% strength aqueous dispersion of a polymer of
92% by weight of MMA
7% by weight of AAEM
1~ by weight of MAA
T8: 97C
Emulsifier: 0.9~, based on monomers, of sodium
laurylsulfate
pH: 4.8
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A suspension of
240 g of basalt wool
90 g of kaolin
15 g of aluminium hydroxide
57 g of the abovementioned polymer dispersion
3 g of a commercial, abou~ 35% strength, polysiloxane
dispersion as a water repellant agent
in ~ 1 of process water i~ prepared with gentle stirring.
About 3 minutes are required for this purpose. This
suspension is flocculated by adding 4.5 g of a 10~
strength aqueous solution of a polymer of 70% by weight
of acrylamide and 30% by weight of diethylaminoethyl
acrylate. The fiber slurry thus obtained is poured into
a wire frame having a wire area of 25 cm x 25 cm and is
lS distributed uniformly using a wooden spatula. The fiber
slurry layer is drained under slightly reduc~d pressure
and with careful pressing with a punch t25 cm x 25 cm,
pressure not more than 0.1 bar~, no more than 0.5 minute
being required for this purpose.
A crude board about 18 mm thick and having an
average residual moisture content of 60% is obtained.
The crude board is dried on siliconized paper in a
circulating-air dryer at 180C, drying taking about 2.5
hours.
Properties of the mineral fiber board
Density : 0.33 g/cm3
Water absorption after 1 h: 5.5
after 2 h: 8.2~
Dimensional stability : less than 1 mm after 290 h
EXAMPLE 2
Binder: 46% strength aqueous dispersion of a polymer of
88% by weight of NMA
12% by weight of AAEM
T8 : 85C5 Emulsifier: 1.3%, based on monomers, of sodium Cl2-Cl5- alkylsulfonate
pH : 5.5
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Procedure according to Example 1
The following are used:
250 g of basalt wool
lO0 g of kaolin
38 g of the abovementioned polymer dispersion
8 g of corn starch
Flocculant and water repellant agent according to Example
1.
Properties
Density : 0.31 g/cm3
Water absorption after 1 h: 6.0%
after 2 h: 7.9%
Dimensional stability : 1 mm after 288 h
EXAMPLE 3
Binder: 48% strength aqueous dispersion of a polymer of
60% by weight of NMA
25~ by weight of AN
10% by weight of AAEM
5~ by weight of MA
T8 : 79C
Emulsifier: 1.7%, based on monomers, of sodium oleate
pH : 8.1
The following are used:
235 g of slag wool
80 g of kaolin
lO g of aluminum hydroxide
37 g of the abovementioned polymer dispersion
Procedure, flocculant and water repellant agent according
to Example 1.
Properties
Density : 0.30 g/cm3
Water absorption after l h: 4.9%
after 2 h: 7.9%
Dimensional stability : 1 mm after 280 h
EXAMPLE 4
Binder: 43~ strength aqueous dispersion of a polymer of
73~ by weight of S
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- 17 - o.z. O0S0/42165
15% by weight of n-BA
12% by weight of AAEM
T8 : 79C
Emulsifier: 3.2%, based on monomers, of sodium oleate
S pH : 7.8
The following are used:
240 g of slag wood
95 g of kaolin
lS g of aluminum hydroxide
6.3 g of potato starch
36 g of the abovementioned polymer dispersion
Procedure, flocculant and water repellant agent according
to Example 1.
Properties
Density : 0.29 g/cm3
Water absorption after 1 h: 4.3%
after 2 h: 5~8~
Dimensional stability : less than 1 mm after 291 h
EXAMPLE 5
Binder: 45.8% strength aqueous dispersion of a polymer
of
60% by weight of S
20% by weight of AN
12% by weight of n-BA
8% by weight of AAEM
~8 : 89C
Emulsifier: 3.5%, based on monomers, of sodium oleate
pH : 8.5
~he following are used:
220 g of slag wood
120 g of kaolin
10 g of aluminum hydroxide
7.5 g of corn starch
27 g of the abovementioned polymer dispersion
Procedure, flocculant and water repellant agent according
to Example 1
Properties
2~5~
- 18 - o.Z. 0050/42165
Density : 0.33 g/cm3
Water absorption after 1 h: 5.8%
after 2 h: 7.1%
Dimensional stability : less than 1 mm after 266 h
S EXAMPLE 6
Binder: 39% strength aqueous dispersion of a polymer of
78~ by weight of MMA
16% by weight of NA
6~ by weight of cyanoacetoxyethyl methacrylate
T8 : 75C
Emulsifier: 0.9% based on monomers, of sodium C12-Cls-
alkylsulfonate
pH : 5.1
The following are used:
235 g of slag wood
80 g of kaolin
12 g of aluminum hydroxide
2.5 g of corn starch
50 g of the abovementioned polymer dispersion
Procedure, flocculant and water repellant agent according
to Example 1.
Properties
Density : 0.28 g/cm3
Water absorption after 1 h: 6.0%
after 2 h: 8.4~
Dimensional stability : 2 mm after 266 h
COMPARATIVE EXAMPLE 1
Binder: 50.8% strength aqueous dispersion of a polymer
of
65% by weight of MMA
30% by weight of AN
5% by weight of MA
T8 : 81C
Emulsifier: 1.85~, based on monomers, of sodium laurate
pH : 6.7
The following are used:
235 g of slag wood
2~S~2~
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80 g of kaolin
10 g of aluminum hydroxide
35 g of the abovementioned polymer disp~rsion
Procedure, flocculant and water repellant agent according
to Example 1.
Properties
Density : 0.32 g/cm3
Water absorption after 1 h: 13.7%
after 2 h: 25.1%0 Dimensional stability : 3 mm after 268 h
EXANPLE 7
A suspension of fibers in 6 1 of wa~er is prepar-
ed with thorough stirring. About 3 minutes are required
for this purpose. If necessary, a water repellant agent
is then added. The next step is the addition of the
aqueous binder dispersion, if necessary followed by
aluminum sulfate. 4.5 g of a 10% strength aqueous
solution of a polymer of 70~ by weight of acrylamide and
30% by weight of diethylaminoethyl acrylate are added as
flocculant, likewise with stirring.
For sheet formation, the fiber slurry is poured
into a wire screen having a wire area of 25 cm x 25 cm
and the material is distributed uniformly by means of a
wooden spatula. The material is then drained under
slightly reduced pressure. Moist crude boards, which are
generally from 8 to g mm thick and contain about 60% of
water are obtained with gentle pressing (less than 0.1
bar) with a punch (25 cm x 25 cm) and suction filtration.
The crude boards are dried in a microwave oven to
residual moisture contents of from 10 to 15~ and then in
a heated press at 220C and 50 kp/cm2 for 90 s.
Binder: 45% strength aqueous dispersion of a polymer of
62% by weight of MMA
20~ by weight of AN
10% by weight of MA
8% by weight of AAEM
T8 : 82C
2~5~2~
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Emulsifier: 2.1%, based on monomers, of sodium laurate
pH : 8.5
The following are used:
105 g of wood fibers
10 g of cellulose fibers
10 g of polypropylene fibers
15 g of an 8% strength aqueous emulsion of stearyl-
diketene (water repellant agent)
18 g of the abovementioned polymer dispersion
11 g of an aqueous 10% strength aluminum sulfate solu~ion
4.5 g of a flocculant
Properties
Density : 0.85 g/cm3
Water absorption after 1 h: 6.5~
after 2 h: 8.0%
Breaking force : 12 N/mm2
EXAMPLE 8
Binder: 41% strength aqueous dispersion of a polymer of
75% by weight of S
15~ by weight of n-BA
10% by weight of AAEM
T8 : 80C
Emulsifier: 4.0%, based on monomers, of sodium oleate
pH : 8.0
The following are used:
6 l of process water
100 g of wood fibers
10 g of cellulsoe fibers
10 g o~ polypropylene fibers
24 g of the abovementioned polymer dispersion
4.5 g of the flocculant as described in Example 7
Properties
Density : 0.87 g/cm3
Water absorption after 1 h: 5.0%
after 2 h: 7.5%
Breaking force : 14 N/~m2
2 ~
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EXAMPLE 9
sinder: 46.s~ strength aqueous dispersion of a polymer
of
91% by weight of MMA
9% by weight of AAEM
T8 : 91C
Emulsifier: 2.8%, based on monomers, of sodium laurate
pH : 7.5
The following are used:
6 l of process water
90 g of wood fibers
10 g of cellulose fibers
20 g of polypropylene fibers
l9 of the abovementioned polymer dispersion
3 g of a 10% strength aqueous aluminum sulfate solution
4.5 g of the flocculant as described in Example 7
Properties
Density : 0.76 g/cm~
Water absorption after 1 h: 4.5%
after 2 hs 6.0%
Breaking force : 12 N~mm2
EXAMPLE 10
Binder: 38% strsngth aqueous dispersion of a polymer of
82~ by weight of S
10% by weight of MA
7% by weight of acetoacetoxy-n-butyl acrylate
1% by weight of AA
T~ : 95C
Emul~ifier: 2.7~, based on monomers, of sodium laurate
pH : 8.3
The following are used:
6 l of process water
100 g of wood fibers
5 g of cellulose fibers
15 g of polyacrylonitrile fiber~
24 g of the abovementioned polymer dispersion
4.5 g of the flocculant a~ described in Example 7
2~5~
- 22 - O.Z. 0050/42165
Properties
Density : 0.91 g/cm3
Water absorption after 1 h: 6.0%
after 2 h: 7.2~
Breaking force : 14.5 N/mm2
EXAMPLE 11
Binder: 42.5% strength aqueous dispersion of a polymer
of
80~ by weight of S
10~ by weight of EHA
5% by weight of 1,1-dibenzoyl-2-acrylamidoethane
5~ by weight of AA
T8 : 88C
Emulsifier: 0.25% sodium lauryl sulfate and
2.7~ of sodium oleate, based in each case on
monomers
pH : 8.1
The following are used:
6 1 of process water
20100 g of wood fibers
10 g of polyacrylonitrils fibers
10 g of polypropylene fibers
25 g of the abovementioned polymer dispersion
4.5 g of the flocculant as de~cribed in Example 7
25Properties
Density : 0.95 g/cm3
Water absorption after 1 h: 4.0~
after 2 h: 5.8%
Breaking force : 13 N/mm2
30EXAMPLE 12
Binder: 44% strength aqueous dispersion of a polymer of
79~ by weight of S
5~ by weight of AN
10% by weight of EHA
355% by weight of 1-benzoyl-1-acetyl-2-acrylamidoethane
1% by weight of AA
T8 : 80C
2 ~ 2 ~
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Emulsifier: 1~ of sodium oleate and
0.5% of sodium laurate, based in each case
on monomers
pH : 7.9
The following are used:
6 1 of process water
g5 g of wood fibers
5 g of cellulose fibers
10 g of polyacrylonitrile fibers
10 g of polypropylene fibsrs
26 g of the abovementioned polymer dispersion
4.5 g of the flocculant as described in Example 7
Properties
Density : 0.83 g/cm3
Water absorption after 1 h: 5.6%
after 2 h: 7.0%
Breaking force : 12 N/mmZ
EXAMPLE 13
Binder: 49.3~ strength aqueous dispersion of a polymer
of
90% by weight of MMA
5% by weight of AAEM
5% by weight of AA
T~ : 102C
Emulsifier: 2.1%, based on monomers, of sodium olea~e
pH : 7.5
The following are used:
6 1 of process water
100 g of wood fibers
10 g of polyacrylonitrile fibers
10 g of polypropylene fibers
21 g of the abovementioned polymer dispersion
4.5 g of the flocculant as described in Example 7
Properties
Density , 0.85 g/cm3
Water absorption after 1 h: 4.0~
after 2 h: 6.9%
2 ~
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Breaking force : 15 N/mm2
COMPARATIVE EXAMPLE 2
Binder: 40~ strength aqueous dispersion of a pol~mer of
60% by weight of ~MA
S 30~ by weight of n-BA
10% by weight of MAA
T8 : 78C
Emulsifier: 1.35%, based on monomers, of sodium
laurylsulfate
pH : 7.3
The following are used:
86 g of wood fibers
lO g of cellulose fibers
: 24 g of polypropylene fiber~
24 g of an 8% strength aqueous stearyldiketene emulsion
24 g of the abovementioned polymer dispersion
25 g of a 10% strength aqueous aluminum sulfate solution
4.5 g of the flocculant as described in Example 7
Properties
Density : 0.80 g/cm3
Water absorption after 1 h: 11.0%
after 2 h: 15.0~
Breaking force : 8 N/mm2
COMPARATIVE EXANPLE 3
Binder: 30.2~ strength aqueous dispersion of apolymer of
70~ by weight of ~MA
30~ by weight of MAA
~8 : 128C
Bmulsifier: 1.2~, based on monomers, of sodium
laurylsulfate
pH : 4.0
The following are used:
86 g of wood fibers
10 g of cellulose fibers
24 g of polypropylene fibers
24 g of an 8~ strength aqueous stearyldiketene emulsion
24 g of the abovementioned polymer dispersion
2 ~
- 25 - O.Z. 0050/~2165
25 g of a 10% strength aqueous aluminum sulfate solution
4.5 g of the flocculant as described in Example 7
Properties
Density : 0.81 g/cm3
Water absorption after l h: 10.0%
after 2 h: 16.0%
Breaking force : 7 N/mm2
COMPARATIVE EXAMPLE 4
Binder: 29.2% strength aqueous dispersion of a polymer
of
6Q~ by weight of MMA
35% by weight of n-BA
5% by weight of AAEM
T6 : 61C
Emulsifier: 1.4~ of the Na salt of a half-ester of an
ethoxylated fatty alcohol with sulfuric acid
(degree of ethoxylation: 2)
pH : 2.9
Procedure according to Example 1
The following are used:
250 g of basalt wool
100 g of kaolin
60 g of the abovementioned polymer dispersion
Properties
Density : 0.28 g/cm3
Water absorption after l h: 49.0%
after 2 h: 58.9%
Dimensional stability : Fracture after 190 h
COMPARATIVE EXAMP~E 5
Binder: As in Comparative Example 4
Procedure according to Example 7
The following are used:
105 g of wood fibers
10 g of cellulose fibers
10 g of polypropylene fibers
15 g of an 8% strength aqueous emulsion of stearyl-
diketene (water repellant agent)
2~59~
- 26 - O.Z. 0050/42165
29 g of the abovementioned polymer dispersion
ll g of 10% strength aqueous aluminum sulfate solution
4.5 g of a flocculant
Properties
Density : 0.69 g/cm3
Water absorption after 1 h: 41.8%
after 2 h: 56.6%
Breaking force : O.2 N/mmZ
