Note: Descriptions are shown in the official language in which they were submitted.
3~
This invention relates to a novel inorganic-
or~anic comblned material and an expanded product
CQmprisin~ cell walls constituted of said material and
also to a process for producin~ said material and
expanded product thereof.
Organic expanded products of prior art such
as polyurethane foams, polystyrene foams or polye-thylene
foams have been known to have excellent thermal
insulating property as well as excellent water
resistanCe and mechanical strength and therefore they
have widely been used as construction materialsg
various lagging materials 9 etc. Since they are organic
in nature~ however, they are very inflammable to the
vital de~ect which has recently been deemed as serious
problem, especially at the time of flre. As organic
expanded products slightly improved in fire-retardant
property 3 there have been also developed such expanded
products of thermosetting resins as phenol foams 3 urea
foams~ etc. But these materials are not substantially
changed in inflammability and have only insufficient
fire-retardant property.
On the other hand, as nonflammable expanded
products~ there have been developed various inorFanic
expanded products such as cernent foams, gypsum foarns
or glass foams. All of these are brittle and have
only insufficient water resistance due to the inor~anic
nature.
For improvement of these drawbacks~ there are
man~ attempts to incorporate inorganic components into
. ~
~ ir ~;
~,~,
3 .~ ~
OrganiC ~XI)LIIId~d prod~lcts. Thes~ components, however, are
generally incompatib]e with ~ach other and, especicllly when a
large amount of inorgan:;c component is incorporated, mechanical
strength is noticeably lowered ~o give no excellent expanded
product. It is also well known to those skilled in the art that
improvement of nonElammability is smaller than is expected even
when a large amount of inorganic components may be incorpo~ated.
In one particular aspect ~he present invent:ion prov:ides
an inorganic-organic combined material comprising a co-
hardened product containing 100 parts by weight of a hardened
product of at least one polyvalent metal phosphori.c aci.d
salt and 1 to 400 parts by weight of a hardened product of a
thermosetting resin curable with an acid catalyst, the
. equivalent ratio of the said metal to the phosp~oric acid
groups in said phosphoric salt being larger than 0.65, whlle
the atomic ratio of the metal atoms to the phosphorus atoms
being larger than 0.67, said polyvalent metal being at least
one selected from the group consisting of magnesium, calcium,
strontium, barium, zinc, manganese (II), copper (II), iron
(II), aluminum, iron (III), titanium (III), cobalt, and
zirconium and said thermosetting resin being at least one
selecLed from the group consisting of resol type phenol.
resin, melamine resin~ urea resin, furan resin, melamine- ;
urea copolymer resin, furan-phenol copolymer resin and
phenol-urea copolymer resin.
In another particular aspect the present invention provi.des
a process ~or producing an inorganic-organic combined material,
which comprises mixing (a~ a water soluble acidic pllosphoric
acid salt of at least one polyvalent metal wherein the
`~
~ jl/i ~3- ~
equ-Lvalellt ratio of the metai :ions to the phosphate ions is
in the range of ~rom 1/9 to 3/4 ancl the atomic rat:io of the
metal atoms to the phosphorus atoms i9 in the range of from
1/6 to 3/2, (b) a hardening agent capable of hardening said
phosphoric acid salt and (c~ a thermosetting resin curable
with an acid catalyst at a mix:ing ratio of 1 to 400 parts by
weight oE (c) to 100 parts by weight of (a)-l-(b), said thermosetting
resin being at least one selected from the group consistLilg
of resol type phenol resin, melamine res:Ln, urea res:in,
f-lran resin, melamine-urea copolymer resin, Euran-phenol
copolymer resin and phenol-urea copolymer resin, and then
allowing the resultant mixture to harden.
.
,~
3a-
; ~
. ~:
.. ..
: . ' . ' ~ : ::
~ : , ~ . -,: .
. 4
According to a preferred embodiment of the
present invention, there is provided an expanded product
havin~ cell walls constltuted o~ the novel inorganic-
or~,anic combined material as mentioned above, having an
average cell diameter of less than 3 mm and a bulk
densit~ of less tha.n 0.5 3 which can readily be prepared
by carryin~ out the above process in the presence of a
blowing a~ent~ thereby effectin~ expansion of the mixture
simultaneously with hardenin~.
In the accompanyin~ drawings:
~ ig. 1 shows a mi.croscopic photograph (magnifi-
cation:xlOO) of the surface of the molded co-hardened
product according to the present invention (Example 2),
Fig. 2 a microscopic photograph (magnifi--
cation:xlOO) of the surface of the molded organic-
inorganic combined material of prior art (Comparison
example l);
~ ig. 3 a microscopic photograph (magnifi-
cationoxl3) of an expanded co-hardened product
according to the present invention (Example 8);
Fig. 4 a microscopic photograph (m~nifi-
- cation x13) of the expanded co--hardened product as
sh~wn in Fig. 3 a~ter it is subjected to burning to
remove the organic hardened product.
I'he specific feature of the inorganic~organic
combined expanded product provided according to the
preferred embodiment of the present invention resides
in the cell walls which are constituted of the
integrall,y combined inorganic and organic components~
-- 5 --
as substarltially distlnguished over the organic--inorganic
mixed expandecl product of prior art in whlch powclery
inorganic components are dispersed on cell walls made
of organic components. The difference can evidentl~
been seen lrom inflammability~ mechanical strength,
water resistance, foaming or others of these products.
The novel inorganic-organic combine(l material
of the present invention has a specific structure~ in
which both inorganic and organic hardened components,
each being formed into a three dimensional network
as the result of simultaneous hardening~ exist in a
homogeneous mixture~ being bound by or intertwined in
one another. Such a structure can be obtained by the
specific co-hardening of the both components. The
starting materials (A) and (C) to be used in the
- present invention are both aqueous solutions, one
bein~ an aqueous solution of a water-soluble acidic
phosphoric acid salt of at least one polyvalent metal
and the other being an aqueous solution of a thermo-
setting resin curable with an acid catalystO These
solutions are completely compatible and mixed to form
a completely homogeneous mixtureO By initiating
hardening of the phosphoric acid salt wlth a hardening
agent (B) simultaneously with hardening of the
thermosetting resin with an acid catalyst~ provided
by the acidic phosphoric acid salt~ there ensues
co-hardening of the both components whereby the
molecules of each component are crosslinked to form
segments of a three-dimensionally crosslinked network.
.~..... . . ~ -
' '; '~
_ r,
As the result of simultaneous hardening of the homo-
geneQusl~ mixecl solution~9 the resultant hardened
produc~s of each component are cons~dered to be such
that the,y are present in a completely homogeneous
matrix in whlch both segments of the three dimensional
network are uniforml,y distributed~ one being bound by
the other. While details of such a structure remain
to be elucidated~ it, can rairly be distinguishecl over
the well-known inor~anic--organlc combined material
structure of prior art9 in which one component is
present as i'islandsl1 dispersed in the "sea" or matrix
of the other component. This can be evidenced at least
b,y the residue of the materialg when one component is
removed from the material. In the accompanying
drawings, Fig. 4 shows the microscopic photograph
of the residue of the expanded product of the inorganic~-
organic combined material of the present invention~
when the organic component is removed by burnin~ the
expanded product. As is clearly shown, the lnor~anic
component remained retains the original shape of the
expanded productg indicating that the inorganic
component as well as the organic component are present
throu~hout the entire matrix of the expanded product 3
~orming individually by skeltons which are bound by
each other. Thus~ the or~anic-inorganic combined
material of the present invention is a mixture of
organic and inorganic components having single solid
phase~ having an appearance as if' it were made of`
single component. The excellent ph,ysical properties
.,
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such as rnechanical strength as compared with the material
of the prior art are reflected in the inor~anic--or~anic
comblned material of the present invention due to such
a structure.
The hardened product Or the phosph~ric acid
salt in the present invention is a hardened product of
a phosphoric acid salt of at least one polyvalent metals
selected from the ~roup conslstin~ o~ magnesium~ calcium,
strontium, barlum~ æinc9 manganese(II), copper(II)
1~ iron(II), aluminumg iron(III), titanlum(III) 3 cobaltg
and zirconium or a phosphoric acid salt of said poly-
valent metals in which a part of the pol~valent metals
is substituted with an alkali metal such as lithium9
sodium, potassium or the like~ or quaternary ammonium
salt. The equivalent ratio (hereinafter referred to as
i'E-valuel') of the metals to phosphoric acid gr~ups i.n
said phosphoric salt is desirably larger than o.659
while the atomic ratio (hereinafter referred to as
- ~IM/P-value'')of the metal atoms to the phosphorus atoms
is desirably larger than o.67. The E value and the
M/P-value herein mentioned are defined by the following
formulas~
~i x ~i
E - -3~
~Ei
M/P = N
, .
.
.
wherein i indicates val.ence o:f the metals, Ei the number
of atoms of .he rnetals in the phosphoric acid salt with
valence i and Np the number of phosphorus atoms in the
phosphoric acid salt~ When the E value is smaller than
o.65 or the M/P-value smaller than 0.679 the phosphor~c
acid salt cannot completely be hardened to give
unfavorably in~erior properties as ko water resistance9
heat resistance 9 hardness and mechanical strength.
The hardenecl product o r the phosphoric acid
salt can be formed by reacting a hardenin~ agent with
a phosphoric acid salt havin~ E-value in the range from
1/9 to 3/4 and M/P~value in the range from 1/6 to 3/2
or an aqueous solution thereof. The hardening agent to
be u.sed in the present i.nvention may include at least
one selected from the group consistlng of the metals
havin~ two or more valences such as magnesium~ calciumg
. strontium~ barium, zinc9 manganese(II~g coppertII)g
iron(II), aluminumg iron(lII)g titanium(III)g cobalt
and zirconium, and hydroxidesg oxidesg silicates,
titanates and carbonates of said metals. In order to
allow the hardening reaction of the phosphoric acid
: or an aqueous solution thereof to proceed smoothly to
:. ~ive favorable hardened productg the E value is required
to be in the ran~e rrom 1/9 to 3/LI and the M/P-v~lue
in the range from 1/6 to 3/2. If the R-value is smaller
than 1/9 or the M/P-value smaller than 1/6; the acidity
.~ of said phosphoric acid salt is too highg whereby
the reaction with the hardening agent is uncontrollably
too vigorous. On the contrary9 if the E-value is larger
,
_ 9 ~
than 3~4 or ~he ~1/P~value larger than 3/2, thermoplasticity
or water solubility Qf said phosphoric acid salt ls
unfavourably poor to give no Kood hardened produc-t.
Further~ in this case, the acidity is too weak to have
catal,ytic activit,y sufficient for hardenin~ of the
thermosetting resin curahle with an acid catalyst as
hereinafter descrlbed. Of course~ as mentioned above 3
the E value after hardening is required t,o be greater
than o.65~ whîle the M/P^value great;er than o.67~
10 Thus~ the amount of the hardening agent can be deter- ~,
mined corresponding to these requirements.
When an expanded product i,s desired to be
obtainedg this hardening reaction is conducted in the
presence of a blowing agent. As blowing agents, there
may be employed water~ low boiling point fluoro-
carbons or hydrocarbons (e.g. ~reon, pentane~ etc.)~
hydrogen peroxide3 metallic powders or carbonates.
Further~ compressed gas such as nitrogen~ argon or
air ma~ also be available. Especially when carbonates
or metallic powders of a metal having two or more
valences are used as hardening agent, they can function
as blowing a~ent simultaneously as hardening agent to a
great advantage.
The thermosettin~; resins curable with an acid
catal,yst to be used in the present invention may
preferably be water~-soluble resins, includin~ resol
type phenol resins, melamine resins, urea resins~ furan
resins9melamine--urea copolymer resins~ furan-urea
copolymer resins~ phenol-urea copolymer resins and `~A
..
, ''~ ', ' ~ '
', ' ~, ~
1 o . . ~ ff ~
ketone res3.ns, ~s descr~bed above, the acidic phosphoric
acid salt under~oes p~l charl~e with lapse ol' time in the
course of the reactio~ with the hardening agent and the
blowillg a~ent until it ls changed to neutral region org
in some cases, to alkaline re~ion. During this procedure~
the aforesaid thermosetti.ng resin curable with an acid
catalyst is hardened to give an inorganic-organic
combined material having integrally--formed inorganic and
organic components, I.1sua.11yg an expanded product is
prepared by mixing the .four components of the phosphoric
acid saltg the hardening agent, the blowing agent and
the thermosetting resin curable with an acid catalyst
and sub~jecting the resultant mixture t,o expansion and
hardening at room ~emperature or under heating.
The thermosetting resin in the inorganic--
; organic comblned expanded product of the present
invention is required to be contained in an amount
of 1 to 400 parts by wei~ht based on 100 parts by weight
of the hardened product of the phosphoric acid salt.
An amount less than one part by weight will be insuffi-
cient to give significant effect by introduction of
the organic componentg while an amount in excess of
400 parts by wei~ht will worsen noticeably the non
flammability to an extent comparable with that Of the
expanded product made of the thermosettin~ resin alone.
For practicing the present invention more
preferably, both of the phosphoric acid salt and the
thermosetting resin are used in the state of liquids
or solutionsg whereby more complete compatibility
-- 1 1 --
can be obtained to a great advantageO According to this
odimerlt 9 the solutions of' the phosphoric acid salt
and the thermosetting resin are completely mixed
together to be made compatlbleg followed by mixing with
hardening agent and~ if necessary~ the blowing agent to
give desired inorganic~organic combined materialO
According to another preferred embodiment, the hardening
agent and9 if` necessary, the blowing agent are prevlously
dispersed in the solution of the thermoset-ting resin and
the resultant dispersion is then mixed with the afore
said solution of the phosphoric acid salt. This
embodiment enables production o~ the desired inorganic~
organic combined material by way of two--liquid mixing~
and there~ore it is most suitable for moldirlg at the
site or injection molding.
For practicing the present prccess according
to the above embodiment by way of two-liquid mixing~
it is convenient to use a set of materials~ comprising
~(A) an aqueous solut,ion of the phosphoric acid salt as
- 20 mentioned above containing 30 to ~5 wt,% of said phos-
phoric acid salt, (B) a slurry containing 30 to 80 wt.
of solids in which a hardening agent as mentioned
above is dispersed in an aqueous solution of a thermo~
setting resin as mentioned above at a weight ratio of
25 hardening agent to thermosetting resin of 1/1 to 1/40,
and optionally (C) a blowing agent. By use of such a
set of materials~ the inorganic-organic combined
material can readily be prepared at the site at which
- it is used by formulating the materials according to
`~ , . - ~
.
. . , .
tile~ composition of the desired pLocluc.t.
In practicing -the present invent.ion, there may also be used additives
such as reinforcing materials, aggregates, f.illers, water repellan-ts,
stabilizers, pigments, surfactants, e-tc. In particular, as wa-ter repellants,
there may be advantageously used in the present inventiP~, other than paraffin
or silicone oil, those compounds having both hydrophobic groups and functional
groups :reactive with the metal salt of phosphor.ic ac:id.
- As mentioned above, the inorganic-o.rganic combined expanded product
can provide useful materials for light weigh-t construction materials or lagging
ln ma-terials. In particular, i-t i9 possible to form.the expanded produc-t at the
site at which it is applied to a grea-t commercial advantage.
The inorganic-organic combined e~panded productJ when it con-tains l to
20 parts by weight of the organic componen-t, can be improved in brittleness
inherent in the inorganic material substantia].ly wi.thout impa~ing nonflammabili:ty.
When the organic content is in the range from 20 to 120 parts by weight, mechanical
strength, water resistance and other properties are noticeably improved, and
inflammability is extremely l~wer due to the cell wall st~ucture as mentio~ed
above in which the lnorganic and organic components e~ist e~ masse, whereby
there is obtained an e~panded product comparable to semi..no~1am~able materials~
12 - 1.
.
g~
~ 13
The expanded products with or~r!anic content in the range
~rom 120 to lloo parts by weight are also lower in in--
flammabillty and have oxygen lndex values by far hi~her
than conventional organic expanded products. In
addition9 they are by far superior in mechanical
strength to the organic expanded products of prior art
in which inor~anic components such as inorganic fillers
are merely dispersed.
As described above~ the inorganic-organic
combined expanded product provided according to the
present invention has excellent characteristlcs which
are not found in inorganic foams, organic ~oams or
organic-inorganic mixed foams in which organic and
inorganic components are inhomogeneously mixed.
The present invention is further illustrated
below with reference to the following Examples.
In the Examples~ thermal conductivity is
measured by ASTM--C518. The oxygen index is measured
by means of Inflammability Tester ON~1 (produced by
Suga Testin~ Machine Co., I.td.)~ using test strip of
5 mm x 5 mm x 100 mm.
.
.
Exampl~ 1
Phosphoric acid
(75% aqlleous solution) 160 wt. parts
Aluminum hydroxide 20 WtD parts
Zinc oxide 35 wto parts
The above components are mixed to carry out
the reaction~ whereb~ there is obtained a transparent
viscous solution having E-value=0.44 and M/P-value=0.56.
On the other hand~ -there ls also prepared a
slurry having 30 wt. parts of fused ma~nesiurn oxide
dispersed in 50 wt. parts of a commercial]y available
aqueous urea resln solution (solid content 70%~ Ply~
amine P-364 BL~ trade mark3 produced by Dainippon Ink
CO~g l,td.).
The above solution and the slurry are mixed
- together and sufficiently stirred. The resultant
mixture is cast into a mold~ng frame of 2 cm x 2 cm x
10 cm. A~ter 6 hours~ hardening is found ko be completed
to give a block of hardened product having R-value of
20 o . 81~ and M/P value of 1.5. This product is found to be
semi--kransparent and have specific gravity of 1.9~
compression strength of 650 kg/cm2 and oxygen index of
90 or more.
Example 2
Phosphoric acid
(75% aqueous solution~ ~0 wt. parts
Aluminum hydroxide 10 wt. parts
Zinc oxide 17.5 wt. parts
.
.
,
~ 15 -
l`he above componen~s are mixed to carry out
the reaction9 whereby there is obtained a ~ransparent
~iscous solution h~lvinK E--value=0,44 and M/P-value=0.56.
On the other hand~ there is a]so prepared a
slurry havln~ 15 wt. parts of' dead-burned magnesium
oxide dispersed in 500 wt. parts of the same commercially
available aqueous urea resin solution as used in
Example 1.
The above solution and the slurry are mixed
together~ followed by sufficient stirring~ and cast into
a moldin~ frame of 2 cm x 2 cm x 10 cm. The molded
product is found to be completely hardened after 6 hours
to give a block of a hardened product having E-value of
0.84 and M/P-value of~ 1.5g comprising 100 wt. parts of
15 a hardened product of the phosphoric acid salt and -
350 wt. parts of a hardened product of the urea resin.
This co-hardened product is semi-transparent and has
specific gravity cf 1.5~ compression strength of 1050
kg/cm2 and oxygen lndex of 55Ø Fig. 1 shows the
appearance of this product.
Comparison example 1
Aaueous urea resin solution 500 wt.parts
(Solid content 70 wt.~ 3 Plyamine
P-364 BL, trade markg produced
by Dainippon Ink Co.g l.td.~
Anhydrous calcium sulfate powders 100 wt.parts
To a slurry prepared by mixin~ the above
`; components are added 10 wt. parts of a 10 % aqueous
- phosphoric acid solution. The resultant mixture is
cast in a moldlng f'rame of 2 cm x 2 cm x 10 cm.
:
.
-- 16 ~
~- After 3 hours, complete hardening is effected.
The thus prepared hardened productg containing
100 wt. par-ts of anhydrous calcium sulfate powders and
350 wt. parts of a hardened product of' the urea resin,
is found to have specific gravlty of 1.5 7 compression
strength of 850 kg/cm2 and oxygen index of 25Ø
Fi~. 2 shows the appearance of this product.
Example 3
Phosphoric acid
(75~ aqueous solution) 160 wt. parts
Aluminum hydroxide20 wt. parts
Zinc oxide 35 wt, parts
The above components are mixed and allowed
to react to obtain a transparent viscous solutlon having
E-value of 0.44 and M/P-value of 0,56.
To the above solution are added 100 wt. parts
of an aqueous solution of a commercially available urea
resin (solid content:70~ Plyamine P 364 BL, trade mark~
Dainippon Ink Co.~ Ltd.) to obkain a further vlscous~
transparent solution. Immediatelyg 70 wt. parts of'
powdery basic magnesium carbonate are added to the
solution to be completely mixed therein. Foaming
begins immediately until the mixture is completely
hardened after 6 hours. The E value after expansion
and hardening is found to be o.84 3 and the M/P--value
1.5~
This expanded product is found to have a
bulk density of 0.099 an average cell diameter of
1.9 mm and thermal conductivity of 0.035 kcal/m,hr.C.
. ~
.
~ 17 -
Examples 4 ~ 5 3 Comparison examples 2 - 3
Example 1 i5 repeated except that the amount
o~ the aqueous urea resin solution is varied as shown
in Table 1.
Table 1
Comparison Comparison
_xample 2 Example 4 ~ example 3
Urea resin 2.0 50 600 1500
(wt~ parts)
Urea resin o.6 14.3 171 429
content*l
~1) Urea resin contentO solid urea resin(wt.parts)
per 100 wt. parts of
hardened phosphoric acid
salt
Each of the expanded product obtained has
the properties as shown in Table 2.
Table 2
.... __
Avera~Je Thermal
cell conduc- Compres- !
dia~ tivity sive
Bulk meter kcal/ 0xy~en strength
density (mm) m.hr C index k~/cm
Comparison more less
example 2 0.06 2.1 0.039than than 0,5
Example 4 0,07 1.0 0.038more 1.5
than
9
Example 5 0.17 1.5 0'0LI3 62.5 17.8
Comparison
example 3 0.61 1.0 0.08828.0 35.0
Examples 6 - 7 9 Comparison examples 4 - 5
There are prepared the phosphoric acid
solutions havin~ the compositions as shown in Table 3.
,, .
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Table 3
Comparison Comparison
_am~le 4 Example 6 Fxample 7 example 5
75~ aqueous
phosphoric 160 wt. 160 wt. 160 wt. 160 wt.
acid parts parts parts parts
solution
Aluminum None 20 wt. 25 wt. 20 wt.
hydroxide parts parts parts
Magnesium 2.5 wt. None 10 wt. 10 wt.
oxide parts parts parts
Zinc oxide 5 wt. 20 wt. 20 wto 20 wt.
parts parts parts parts
Sodium None None None 20 wto
hydroxide parts
E value 0.07 0O34 0.53 oO85
M/P-value 0.10 0.41 o.66 1.17
State Colorless Colorless Colorless White
trans trans- trans-- turbid
parent parent parent
Two solutions~ namely each of the phosphoric
acid salt solutions having the above compositions and
200 wt. parts of a urea resin solution (solid contento
70%) having completely dispersed 50 wt. parts of
aluminum silicateg 40 wto parts of magnesium oxide
and 15 wt. parts of pentane dispersed therein, are
mixed together and left to stand. The results are set
forth in Table 4.
:~.
'
3 ~ ~
Table 9
Foaming
Comparison Extreme heat generation with a great shri~kage
example 4 until hardening
Example 6 Foaming with mild heat generation;.
Specific gravity = 0.13
Example 7 Foaming with mild heat generation;
Specific gravity = 0.18
Comparison Neither heat generat.ion nor foaming occurs.
example 5
Comparison example 6
The same procedure as in Example 3 is repeated except 70 wtS
parts of the basic magnesium carbonate are changed to 35 wt, parts~ The
resultant expanded and hardened product is found to have E -value-0~64 and
M/P-value=0.86.
The expanded product obtained is very hygroscopi:c and ~:
exhibits acidity even aEter 4i3 hours.
Example 8
Primary aluminum phosphate .150 wt, parts
:. 20 (50% aqueous solution,
E-value=0.33,
. M~P-value-0.33)
Resol type phenol resin125 wt. parts
(80% aqueous solution,
; BRL-lll, trade mark,
produced by Showa Kobunshi.
Co., Ltd.)
Aluminum powders 20 wt. parts
After mixing the above components, the mixture is left to
stand at 80 C for 30 mimltes in a hot air drier. After hardening, the expanded
product obtained is found to have E-value=l.0, M/P-value=l.0 and specific
gravity of 0.08. Fig. 3 shows the appearance of this product.
.,.`' .
,
: ~ 19
..... '
:
.
3~
~ 20 -
This expancled product is :Lef't to stand in an
electric furnace set at 800C ~or one hour. After the
calcinationg the expanded product is discoloured in
dark but its ori~inal cell structure is maintained
(see Fig. 4~.
Comparison example 7
Resol type phenol resin 125 wt. parts
(80P aqueous solution,
B~L-1119 trade mark~
produced by Showa
Kobunshi Co.g I.td.)
Tertiary aluminurn phosphate 95 wt. parts
powders
Pehtane 5 wt. parts
To the slurr~ having mixed -the above components
are added 20 wto parts of a 10 % aqueous phosphoric acid
solution in which 2.0 wt. parts of p'toluene sulfonic
acid are dissolved. The m~xture is left to stand at
room temperature and, after one minute, foamlng begins
with generation of heat to give an expanded product
having specific gravit~ of 0012.
This expanded product is left to stand in an
electric furnace set at 800C for one hour. After the
calcinationg only powdery carbonized product is remained.
Example 9
Phosphoric acid 160 wt. parts
(75% aqueous solution)
Aluminum hydroxide20 wt. parts
Zinc oxide 20 WtD parts
The above components are mixe~ and allowed
to react to obtain a transparent and viscous solution.
After further adding 1.0 wt. paFt o~ lauryl amine as
.,
,
.
21 ~
water rer,ellanl; and 2.0 wt. parts of' paper pulp as
reillforcing materlal to the so:lution~ 100 wt. parts
of an aqueous melamine resin solution (Nikalac~ trade
mark~ produced by Sanwa Chemlcal Co. 7 Ltd.) having
dispersed 20 wt. parts of metallic aluminum powders
therein are added thereto. After complete mixing~
the mixture is left to stand in a hot air drier set
at 100C for 30 minutes.
- The resultant e~panded product is found to
have specific gravity of 0.16 and also to be endowed
with perfect water repellency.
.
. ., . ~ .
