NONCRYSTALLINE COMPOSITE ALKALI METAL
TITANATE COMPOSITION AND FRICTION MATERIAL
TECHNICAL FIELD
The present invention relates to amorphous or noncrystalline composite
alkali metal titanate compositions, and more particularly to amorphous or
noncrystalline composite alkali metal titanate compositions which are excellent in
chemical stability and thermal stability, and friction materials comprising the
composition.
BACKGROUND ART
Alkali metal titanates represented by the general formula M2O- nTiO2
wherein M is one or at least two alkali metal elements are available usually in the
form of fibrous compounds. Examples of such titanates include potassium dititanate
wherein M is K and n is 2, sodium trititanate wherein M is Na and n is 3, and
potassium tetratitanate wherein M is K and n is 4. However, these alkali metal
titanates contain a large amount of alkali component, have a layered crystal structure
and therefore have the drawbacks of being chemically unstable, permitting alkali
metal ions to dissolve out from between layers during molding of friction materials
and consequently degrading the resin providing the matrix of the friction material.
When containing an increased amount of TiO2, on the other hand, alkali
metal titanates have a tunnel crystal structure and exhibit higher chemical stability.
Such alkali metal titanates include, for example, potassium hexatitanate wherein M
is K and n is 6, sodium hexatitanate wherein M is Na and n is 6, and potassium
octatitanate wherein M is K and n is 8. These titanates are chemically stable,
outstanding in thermal resistance and heat insulating properties and accordingly in
wide use as base materials for friction materials.
Potassium hexatitanate is prepared typically by the melting process, which

comprises cooling and solidifying a molten starting material to obtain fiber blocks of
potassium dititanate. and thereafter swelling the fiber blocks by a hydration reaction,
followed by separation. The separated fibers are then treated with an acid, and
potassium is removed with a solvent until the composition of potassium hexatitanate
is obtained, followed by solid-liquid separation and by heat treatment. In this way,
the material is converted to potassium hexatitanate of tunnel structure (Japanese
Patent No. 2946107).
DISCLOSURE OF THE INVENTION
[Problem to be Solved by the Invention]
The potassium hexatitanate prepared by the above melting process requires
the conversion of potassium dititanate to potassium hexatitanate, and the preparation
process is complex. Furthermore, the removal of potassium with a solvent results
in a low theoretical yield.
Additionally, the titanate obtained by the melting method is in the form of
platelike fibers, which are difficult to shape to a form other than plates.
An object of the present invention is to provide an noncrystalline composite
alkali metal titanate composition which is chemically stable, excellent in resistance
to hygroscopicity, thermally stable and suitable for use as base materials for friction
materials, and which can be prepared without necessitating the conventional step of
converting the composition or structure.
We have conducted intensive research and consequently found that
although noncrystalline potassium mono- to tetra-titanates are low in chemical
stability and insufficient in resistance to hygroscopicity like compounds having a
crystal structure if used singly, these compounds can be given chemical stability and
resistance to hygroscopicity when having incorporated therein a specified amount of
SiO2.
[Means for Solving the Problem]

The present invention provides a first noncrystalline composite alkali metal
titanate composition which comprises 60 to 90 wt. % of an alkali metal titanate
represented by the general formula M2O • nTiO2 wherein M is one or at least two
alkali metal elements and n is a number of 1 to 4, and 10 to 40 wt. % of SiO2.
M2O/SIO2 being equal to or less than 2.5.
The present invention provides a second noncrystalline composite alkali
metal titanate composition which comprises at least 60 wt. % to less than 90 wt. %
of an alkali metal titanate represented by the general formula M2O-nTiO2 wherein
M is one or at least two alkali metal elements and n is a number of 1 to 4, at least 10
wt. % to less than 40 wt. % of SiO2 and more than 0 wt. % to up to 10 wt. % of an
oxide of at least one element selected from the group consisting of B, Mg, Al, P, Ca
and Zn. M2O/SiO2 being equal to or less than 2.5.
The present invention provides a third noncrystalline composite alkali metal
titanate composition which comprises at least 60 wt. % to less than 90 wt. % of an
alkali metal titanate represented by the general formula M2O • nTiO2 wherein M is
one or at least two alkali metal elements and n is a number of 1 to 4, at least 10 wt.
% to less than 40 wt. % of SiO2 and more than 0 wt. % to up to 10 wt. % of an oxide
of at least one element selected from the group consisting of V, Cr, Mn, Fe, Co, Ni,
Cu, Y, Zr. Nb and Ba, M2O/SiO2 being equal to or less than 2.5.
The present invention provides a fourth noncrystalline composite alkali
metal titanate composition which comprises at least 60 wt. % to less than 90 wt. %
of an alkali metal titanate represented by the general formula M2O nTiO2 wherein
M is one or at least two alkali metal elements and n is a number of 1 to 4, at least 10
wt. % to less than 40 wt. % of SiO2 more than 0 wt. % to up to 10 wt. % of an oxide
of at least one element selected from the group consisting of B. Mg, Al. P, Ca and
Zn, and more than 0 wt. % to up to 10 wt. % of an oxide of at least one element
selected from the group consisting of V. Cr. Mn. Fe, Co. Ni, Cu, Y, Zr. Nb and Ba.

M2O/SiO2 being equal to or less than 2.5.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a photomicrograph taken by a scanning electron microscope of
flat noncrystalline composite alkali metal titanate composition particles obtained in
Preparation Example 1;
FIG. 2 is a photomicrograph taken by a scanning electron microscope of
flat noncrystalline composite alkali metal titanate composition particles obtained in
Preparation Example 1;
FIG. 3 is a photomicrograph taken by a scanning electron microscope of
fibrous noncrystalline composite alkali metal titanate composition particles obtained
in Preparation Example 2; and
FIG. 4 is a photomicrograph taken by a scanning electron microscope of
spherical noncrystalline composite alkali metal titanate composition particles
obtained in Preparation Example 3.
BEST MODE OF CARRYING OUT THE INVENTION
As already described, the present invention provides an noncrystalline
composite alkali metal titanate composition which comprises at least 60 wt. % of an
alkali metal titanate represented by the general formula M2O-nTiO2 wherein M is
one or at least two alkali metal elements and n is a number of 1 to 4, and at least 10
wt. % of SiO2, M2O/SiO2 being equal to or less than 2.5. When desired, it is
possible to incorporate into the composition an oxide of at least one element selected
from the group consisting of B, Mg, Al, P, Ca and Zn, and/or an oxide of at least one
element selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb
and Ba.
The noncrystalline composite alkali metal titanate composition of-the
present invention is suited for use as base materials for friction materials. The
friction material can be given excellent friction characteristics, when 3-50 wt. % of

the noncrystalline composite alkali metal titanate composition is incorporated
therein.
[Alkali Metal Titanate]
Alkali metal elements are Group I elements of the Periodic Table, such as
Li, Na, K, Cs and Rb.
The noncrystalline properties of alkali metal titanates can be obtained by
melting a starting material mixture with heating and thereafter quenching the
resulting melt. The quenching treatment is conducted typically by the twin-roll
method, such that the melt is caused to flow through a clearance between a pair of
opposed metal rolls which are in rotation at a high speed, passed between the rolls
while being quenched by contact with the rolls and discharged to below as a solid
product in the form of a thin piece. The product is made noncrystalline by the
quenching effect.
The noncrystalline alkali metal titanate thus obtained of the formula M2O
nTiO2 wherein n is a number of up to 4 can be given outstanding chemical stability
and resistance to moisture absorption when containing SiO2 so that when molded
into a friction material, the composition does not permit alkali metal ions to dissolve
out, obviating an adverse effect on the matrix forming resin of the friction material.
In the case of a noncrystalline alkali metal titanate of the formula M2O-
nTiO2 wherein n is a number greater than 4, the titanate is stable even when not
containing SiO2 but may contain SiO2 and an oxide of B, Mg, Al, P, Ca, Zn, V. Cr,
Mn, Fe, Co, Ni. Cu, Y, Zr, Nb, Ba or the like.
Since there is no need for the conversion to a tunnel structure by heat
treatment, treatment for removing alkali metal and baking in order to give chemical
stability like crystalline potassium hexatitanate. the titanate of the invention can be
prepared by a simplified process, while it is possible to avoid a reduction of yield
due to the treatment for removing the alkali metal.

When the alkali metal titanate is used for friction materials, the
noncrystalline structure of the titanate becomes softened and undergoes a melting
reaction in accordance with the friction conditions (temperature, speed, pressure,
etc.) to supply suitable quantities of alkali component and titanium component to the
friction interface, thereby resulting in an effect to exhibit significantly improved
abrasion resistance under varying conditions. To obtain this effect, it is desired
that at least 60 wt. % of the alkali metal titanate be present in the noncrystalline
composite alkali metal titanate composition.
[SiO2]
SiO2 fortifies the network of noncrystalline structure of the noncrystalline
alkali metal titanate, inhibiting the alkali metal from dissolving out in the normal
state to thereby give increased chemical stability and contribute to an improvement
in the resistance to hygroscopicity.
For this reason, at least 10 wt. % of SiO2 is incorporated into the
noncrystalline composite alkali metal titanate composition, and the ratio of the M2O
of the alkali metal titanate to the SiO2, i.e., M2O/Si02, is defined as up to 2.5.
Since the noncrystalline composite alkali metal titanate composition thus
contains at least 10 wt. % of SiO2, the content of the alkali metal titanate is up to 90
wt. %. The composition contains at least 60 wt. % of the alkali metal titanate, so
that the content of SiO2 is up to 40 wt. %.
[Oxides of B, Mg, Al, P, Ca and Zn]
The oxides of B, Mg, Al, P, Ca and Zn act to give improved chemical
durability and stability, further serving to afford improved thermal stability.
Accordingly, it is desired that the composition contain the oxide of at least one
element selected from the group consisting of B, Mg. Al, P. Ca and Zn. However,
the presence of an excess of the oxide upsets the balance between the alkali metal
titanate and SiO2. The upper limit of the oxide content should be 10 wt. %.

Incidentally, in the case where the composition contains the oxide of at
least one element selected from the group consisting of B, Mg, Al, P, Ca and Zn, the
composition contains less than 90 wt. % of alkali metal titanate and less than 40 wt.
% of SiO2.
[Oxides of V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb and Ba]
When the oxides of V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb and Ba are used
as friction materials, these oxides significantly contribute to an improvement in the
coefficient of friction. For this reason, it is desired that the composition contain the
oxide of at least one element selected from the group consisting of V, Cr, Mn, Fe,
Co, Ni, Cu, Y, Zr, Nb and Ba. However, the presence of an excess of the oxide
upsets the balance between the alkali metal titanate and SiO2. The upper limit of
the oxide content should therefore be 10 wt. %.
In the case where the composition contains the oxide of at least one element
selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb and Ba,
the composition contains less than 90 wt. % of alkali metal titanate and less than 40
wt. % of SiO2. The same is true in the case where the composition contains the
oxide of such element in addition to the oxide of at least one element selected from
the group consisting of B, Mg, Al, P, Ca and Zn.
[Friction Materials]
The noncrystalline composite alkali metal titanate composition of the
present invention is suited for use in base materials for friction materials which
provide the sliding faces of brake linings, disk pads, clutch facings, etc. in braking
system of motor vehicles, railway vehicles, aircraft, industrial apparatus and the like.
The noncrystalline composite alkali metal titanate composition for use as
base materials for friction materials is used preferably in an amount of 3 to 50 wt. %
in the friction material.
When desired, the noncrystalline composite alkali metal titanate

composition can be used for friction materials along with known other materials
(such as polyamide fibers, Aramid fibers, steel fibers, copper fibers, glass fibers,
ceramic fibers and crystalline titanate compound fibers). Further when required,
these can be subjected to a surface treatment (coupling treatment) by a silane
coupling agent or titanate coupling agent in the usual manner for assuring improved
dispersibility and higher adhesion to binder resins.
When desired, suitable amounts of known friction- abrasion adjusting
agents can be admixed with the friction material. (Such agents include, for
example, natural or synthetic rubber powders, cashew resin powders or granules,
organic powders, graphite, molybdenum disulfide, inorganic powders, metal
powders and oxide powders.) Suitable amounts of various additives (such as rust
inhibitors, lubricants, abrasives, etc.) can also be used in conformity with the use or
the mode of use.
The friction material of the present invention can be prepared by dispersing
a base material in a binder resin, adding to the dispersion a friction-abrasion
adjusting agent and additives which are used as desired, uniformly agitating the
resulting mixture into a material composition, preforming the composition, molding
the preformed composition with a die, further molding the composition for bonding
with heating under an increased pressure (pressure applied: about 10-40 MPa,
temperature: about 150-200°C), removing the resulting body from the die, thereafter
heat-treating the molded body in a heating furnace (150-200°C for about 1 to 12
hours) when so desired, and subsequently finishing the resulting body into a friction
material having a predetermined shape by machining and grinding.

[Preparation Example 1: Flat Noncrystalline Composite Alkali Metal Titanate
Composition]
Amounts of potassium carbonate (K2CO3) and titanium dioxide (TiO2) were

weighed out so that the TiO2/K2O molar ratio would be 2 and uniformly mixed
together, and the mixture was heated at 800°C for 2 hours to obtain a powder of
potassium titanate (K2O • 2TiO2). To the potassium titanate (K2O • 2TiO2) obtained
were added silica (SiO2) and magnesium hydroxide (Mg(OH)2) in such amounts that
the K2O-2TiO2/SiO2 /MgO weight ratio would be 75/20/5, and the mixture was
placed into a platinum crucible and melted at 1200°C for 1 hour.
A powder was made from the resulting melt by causing the melt to flow
between a pair of metal rolls rotating at a peripheral speed of 3.6 m/s, quenching the
melt and thereafter crushing the resulting solid product by a hammer mill.
The powder obtained was observed under a scanning electron microscope.
FIGS. 1 and 2 show photomicrographs of the powder. The powder was further
checked by X-ray diffraction, and the components were quantitatively determined
by fluorescent X-ray spectroscopy. Consequently, the powder was found to be a
composition of flat noncrystalline composite alkali metal titanate generally in match
with the starting material in composition and measuring about 300 urn in average
diameter and about 80 µm in average thickness.
The specimen composition of Preparation Example 1 is referred to as No. 2
in Table 1.
As an example different from the mixture of Preparation Example 1 in
Ti02/K2O molar ratio and composition, a mixture was used which was 1.9 in
Ti02/K2O and 82/18 in K2O- 1.9TiO2/SiO2for preparing a specimen composition.
This composition is referred to as No. 1 in Table 1.
As another example different from the mixture of Preparation Example 1 in
TiO2/K2O molar ratio and composition, a mixture was used which was 2 in
Ti02/K2O and 75/20/5 in K2O-2TiO2/SiO2/Fe2O3 for preparing a specimen
composition. This composition is referred to as No. 5 in Table 1.
As another example different from the mixture of Preparation Example 1 in

TiO2/K2O molar ratio and composition, a mixture was used which was 2 in
Ti02/K2O and 73/18/4/5 in K2O-2TiO2/SiO2/MgO/ZrO2 for preparing a specimen
composition. This composition is referred to as No. 6 in Table 1.
As another example different from the mixture of Preparation Example 1 in
TiO2/K2O molar ratio and composition, a mixture(containing no SiO2) was used
which was 2 in Ti02/K2O and wherein K2O2TiO2= 100 for preparing a specimen
composition. This composition is referred to as No. 11 in Table 1.
As another example different from the mixture of Preparation Example 1 in
TiO2/K2O molar ratio and composition, a mixture was used which was 1.7 in
TiO2/K2O and 85/11/4 in K2O • 1.7TiO2/SiO2/Al2O3 for preparing a specimen
composition. This composition is referred to as No. 12 in Table 1.
As another example different from the mixture of Preparation Example 1 in
TiO2/K2O molar ratio and composition, a mixture was used which was 3 in
TiO2/K2O and 83/8/9 in K2O-3TiO2/SiO2/MgO for preparing a specimen
composition. This composition is referred to as No. 13 in Table 1.
[Preparation Example 2, Fibrous Noncrystalline Composite Alkali Metal Titanate
Composition]
To potassium titanate (K2O-1.7TiO2) obtained in the same manner as in
Preparation Example 1 with the exception of varying the molar ratio of potassium
carbonate (K2CO3) to titanium dioxide (TiO2) were added silica (SiO2) and alumina
(Al2O3) in such amounts that K2O- 1.7TiO2/SiO2/Al2O3, would be in the ratio by-
weight of 78/18/4. The mixture was placed into a platinum crucible and melted at
1150°C for 2 hours.
The melt obtained was transferred to a heating crucible having a nozzle
hole in its bottom and then allowed to run off from the nozzle end in the form of a
small flow, which was blown away with compressed air, whereby fibers were
prepared.

The fibrous product obtained was observed under a scanning electron
microscope. FIG. 3 shows a photomicrograph of fibers. The product was further
checked for crystalline phase by X-ray diffraction, and the components were
quantitatively determined by fluorescent X-ray spectroscopy. Consequently, the
product was found to be a fibrous noncrystalline composite alkali metal titanate
composition generally in match with the starting material in composition and
measuring about 1500 µm in average fiber length, about 30 urn in average fiber
diameter and 50 in average aspect ratio (length/diameter).
The specimen composition obtain in Preparation Example 2 is referred to as
No. 3 in Table 1.
[Preparation Example 3: Spherical Noncrystalline Composite Alkali Metal Titanate
Composition]
'To potassium titanate (K2O 2.8.STiO2 obtained in the same manner as in
Preparation Example 1 with the exception of varying the molar ratio of potassium
carbonate (K2CO3) to titanium dioxide (TiO2) were added silica (SiO2) and calcium
carbonate (CaCO3) in such amounts that K2O.STiO2/SiO2/CaO would be in the
ratio by weight of 82/12/6, and the mixture was flame-sprayed using a
flame-spraying device (CastoDyn DS8000, product of Eutectic of Japan, Ltd.) and
quenched in water to obtain a powder.
The powder obtained was observed under a scanning electron microscope.
FIG. 4 shows a photomicrograph of the powder. The powder was further checked
for crystalline phase by X-ray diffraction, and the components were quantitatively
determined by fluorescent X-ray spectroscopy. Consequently, the powder was
found to be a composition of spherical noncrystalline composite alkali metal titanate
generally in match with the starting material in composition and measuring about 30
urn in average particle size.
The specimen composition obtain in Preparation Example 3 is referred to as

No. 4 in Table 1.
The composition No. 14 is an example of known crystalline potassium
hexatitanate, which was produced from a mixture having a TiO2/K2O molar ratio of
2 by melting the mixture at 1200°C for 1 hour, cooling the resulting melt for
solidification to obtain a fibrous block of potassium dititanate, swelling the block by
a hydration reaction for separation, treating the fibers with an acid, removing
potassium from the fibers with a solvent, and thereafter subjecting the product to
solid-liquid separation and heat treatment to obtain fibers about 150 µm in average
length and about 30 µm in average width.

With reference to Table 1. No. 1 to No. 6 are examples of the invention, No.
11 to No. 13 are comparative examples, and No. 14 is a conventional example of
crystalline structure. No. 11 is an example containing no SiO2, No. 12 is an
example wherein the value of M2O/SiO2 is larger than the corresponding value 2.5
of the invention, and No. 13 is an example having a low SiO2 content and an
M2O/SiO2 value which is larger than the value 2.5 of the invention.
Referring to Table 1, examples of the invention No. 1 to 6 are smaller in the
weight increase due to water absorption than comparative examples No. 11 to No.
13, hence high resistance to hygroscopicity.
No. 14 is smaller than the examples of the invention in the weight increase
due to water absorption, whereas the composition is crystalline and has the
drawbacks of requiring conversion from potassium dititanate to potassium
hexatitanate. therefore necessitating a complex preparation process and being low in
theoretical yield because of the removal of potassium with a solvent.
[Hygroscopicity Test]
To test the specimen compositions No. 1 to No. 6 and No. 11 to No. 14 for
resistance to hygroscopicity, these compositions were allowed to stand in a
constant-temperature constant-humidity atmosphere of 30°C and 80% RH for 72
hours and thereafter checked for weight increases due to water absorption. Table 1
shows the weight increases.
[Friction Test]
Starting materials for friction materials containing respective compositions
of No. 1 to No. 6 and No. 11 to No. 14 were prepared. Each of the starting
materials was treated in an Eirich mixer for 3 minutes, then preformed (16 MPa,
room temperature, 2 minutes) and molded hot (40 MPa, 170°C, 10 minutes, molding
twice, degassing by a slow decrease in pressure). After molding, the resulting body
was heat-treated (200°C, 5 hours), cut to a predetermined size and ground to obtain a
specimen friction material.
The starting materials for the friction materials each comprise, in % by

weight. 20% of the above prepared composition. 4% of Kevlar pulp. 17% of copper
fiber, 4% of ceramic fiber, 10% of abrasive, 5% of mica, 4% of organic powder, 6%
of lubricant, 20% of barium sulfate and 10% of phenolic resin. Listed in Table 2
are No. 1 a to No. 6a and No. 1 la to No. 14a representing the specimen materials
which were prepared with use of the respective compositions No. 1 to No. 6 and No.
11 to No. 14.
The specimen friction materials were subjected to an abrasion test
according to JASO C427 "Brake Lining, Pad Abrasion Dynamometer Test Method/'
Table 2 shows the results obtained with respect to coefficient of friction (µ), amount
of pad abrasion (mm) and amount of disk abrasion (µm). Incidentally, the
coefficient of friction is an average coefficient value obtained in a stable state at the
temperature indicated. The amounts of pad abrasion and disk abrasion are the
average values obtained per 1000 times of braking.

With reference to Table 2. examples No. la to No. 6a of the invention have
higher friction coefficients than comparative examples Nos. 1 la and 12a over a
low-temperature range (100°C) corresponding to a relatively low braking initial
speed to a high-temperature range (400°C) corresponding to a high braking initial
speed involving a rise in the temperature of the friction face, are smaller in the
amounts of abrasion of the pad and disk and have higher resistance to
hygroscopicity. This appears attributable to a fluid layer formed by the example of
the invention over the friction interface in the low-temperature range to the
high-temperature range, and to a uniform transfer layer formed over the surface of
the counterpart disk surface.
Although No. 13a has a high coefficient of friction comparable to those of
the invention examples, it is larger in the amount of pad abrasion and the amount of
disk abrasion than the invention examples. This is thought attributable to the fact
that the transfer layer formed on the disk surface is more brittle than those of the
invention examples.
Although No. 14a has a coefficient of friction which is substantially
equivalent to or higher than those of the invention examples, it is larger in the
amount of pad abrasion and the amount of disk abrasion than the invention examples.
This is thought attributable to the fact that No. 14a is crystalline, has a high melting
point, does not soften and is therefore somewhat inferior to the invention examples
in forming a fluid layer over the friction interface with stability.
[Advantages of the Invention]
The noncrystalline composite alkali metal titanate composition of the
invention is chemically stable and highly resistant to hygroscopicity as already
described. When used for motor vehicle disk pads and like friction materials, the
composition exhibits under high temperatures and high loads a coefficient of friction
comparable to those of the conventional crystalline alkali metal hexatitanate, further
exhibiting improved friction-abrasion characteristics with respect to abrasion
resistance and damage to the counter surface.

On the other hand, the composition of the invention can be manufactured at
a remarkably reduced cost because the invention does not require the conversion of
composition and conversion of crystal structure to the tunnel crystal structure unlike
the convention crystalline alkali metal hexatitanate and will not lower in yield due to
the removal of alkali metal in the conversion step with a solvent.
The noncrystalline composite alkali metal composition of the invention
further has the advantage that the composition of flat, fibrous or spherical compound
can be prepared as desired by selecting a suitable process.
Flat particles are suitably determined with respect to the formation of pores
and improved strength. Typically, such particles are so sized as to be 10 to 600 µm
in average diameter and 3 to 200 µm in average thickness. Fibrous particles are
suitably determined with respect to the fonnation of pores and further improved
strength. Typically, such particles are so sized as to have an average diameter of 5
to 100 µm and an aspect ratio (length/diameter) of at least 10. Spherical particles
are suitably determined with respect to flowability and dispersibility and are
typically so sized as to have an average diameter of 5 to 100 µm.

CLAIMS FOR NATIONAL PHASE
1. A noncrystalline composite alkali metal titanate composition comprising 60
to 90 wt % of an alkali metal titanate represented by the general formula M2O • nTiO2
wherein M is one or at least two alkali metal elements and n is a number of 1 to 4, and
10 to 40 wt. % of SiO2, and wherein M2O/SiO2 by weight ratio is equal to or less than
2.5.
2. The noncrystalline composite alkali metal titanate composition as defined
in claim 1 wherein said alkali metal titanate is at least 60 wt. % to less than 90 wt. %
and said SiO2 is at least 10 wt. % to less than 40 wt. %, said composition including
more than 0 wt. % to up to 10 wt. % of an oxide of at least one element selected from
the group consisting of B, Mg, Al, P, Ca and Zn.
3. The noncrystalline composite alkali metal titanate composition as defined
in claim 1 wherein said alkali metal titanate is at least 60 wt. % to less than 90 wt. %
and said SiO2 is at least 10 wt. % to less than 40 wt. %, said composition including
more than 0 wt. % to up to 10 wt. % of an oxide of at least one element selected from
the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu. Y, Zr, Nb and Ba.
4. The noncrystalline composite alkali metal titanate composition as defined
in claim 2 wherein said alkali metal titanate is at least 60 wt. % to less than 90 wt. %
and said SiO2 is at least 10 wt. % to less than 40 wt. %, said composition including
more than 0 wt. % to up to 10 wt. % of an oxide of at least one element selected from
the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb and Ba.
5. A friction material for brakes and clutches, said friction material

comprising at least one of the noncrystalline composite alkali metal titanate
composition according to any one of claims 1 to 4.

A noncrystalline composite alkali metal titanate composition which comprises at least 60 wt% alkali metal titanate
represented by the general formula M2O nTiO2 (wherein M is one or more alkali metal elements and n is a number of 1 to 4) and
at least 10 wt.% SiO2 and satisfies M2O/SiO2 ≤ 2.5. It is chemically stable, has excellent resistance to moisture absorption, and is
suitable for use as a base for friction materials. If desired, the composition can further contain an oxide of at least one member
selected from the group consisting of B. Mg. Al. P, Ca. and Zn and/or an oxide of at least one member selected from the group
consisting of V. Cr. Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, and Ba.