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Description  |
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BACKGROUND OF THE INVENTION
This invention relates to a dustproof film forming material, and more
particularly it relates to a room temperature curable film forming
material which can form an excellent dustproof film on the surface of a
silicone elastomer.
There are various known polyorganosiloxane compositions which cure at room
temperature to thereby afford an elastomer. For example, compositions
prepared from polydiorganosiloxane blocked with silanol groups at both
ends and an organosilicon compound which has a hydrolyzable group bonded
to the silicon atom, such as acetoxy, alkoxy, dialkylketoxime,
dialkylamino, dialkylaminoxy, or N-methylamido group as a crosslinking
agent, have been widely used in the construction, automotive and
electrical fields and the like.
These compositions are generally called "silicone sealants" and are widely
used to waterproof joints of concrete or aluminum wall board, to fix a
glass plate to a sash, or to bond two glass plates together in the
construction industry. Demand for these silicone sealants is greatly
increasing for use on high rise buildings or the like because they exhibit
excellent weatherability, durability, high- and low-temperature
resistance, the physical properties are scarcely altered by temperature
change, there is no deterioration by ozone or ultraviolet rays, and the
sealants exhibit high workability. In addition, recently some attempts
have been made at utilizing them as a coating material by applying such a
crosslinkable polyorganosiloxane on a roof or wall to thereby form a
silicone elastomer layer having an excellent waterproofness and
weatherability.
Although these silicone elastomers have the advantages described above,
they are dust attracting because of the tackiness remaining after curing
and primarily because of the dielectric property of the
polyorganosiloxane. In particular, when non-reactive polyorganosiloxane is
added to afford a flexible silicone elastomer without lowering the
workability, such polyorganosiloxane that does not participate in
crosslinking oozes from inside to the surface and covers the attracted
dust. The resulting water-repellent dust is not washed away by rain,
thereby damaging the appearance considerably.
The disadvantage of these silicone elastomers in maintaining the building's
appearance, which is one of the requirements of a construction material,
restricts their utilization. Furthermore, the dust attraction would damage
the appearance or utility of industrial materials other than construction
materials in many cases. Therefore, development of a technique for
preventing the adhesion of dust to the surface of silicone elastomers has
been an urgent problem in various fields including the construction
industry.
A process for preventing the adhesion of dust to the surface of a silicone
elastomer is disclosed in Japanese Patent Laid-Open No. 1627631/1982.
According to this process, the surface of a silicone elastomer is coated
with a known coating to which dust is hard to adhere. More particularly,
an alkyd resin and a room temperature curable polysiloxane composition,
which consists of polydiorganosiloxane end-blocked by silanol groups and
having a certain degree of polymerization and a silicon compound having a
hydrolyzable group, are dissolved in an organic solvent, and the resulting
composition is applied on the surface of a silicone elastomer to thereby
form a dustproof film. The resulting film exhibits excellent resistance to
dust. However, it has a disadvantage in that so-called cissings and
unevenness would occur unless the coating process is carried out in a
somewhat viscous state thereby sacrificing its workability.
As a result of investigations about these disadvantages, the present
applicant has found that a film forming material prepared by adding an
organic solvent containing a volatile organosilicon compound to a
composition consisting of an alkyd resin and hydrolyzable silane, siloxane
or optionally polydiorganosiloxane end-blocked by silanol groups, exhibits
excellent workability, wetting property and adhesion to silicone
elastomers at a lower viscosity, and furthermore the resulting film has
excellent resistance to dust and weatherability. At first, this film
forming material was prepared as a two-package formulation consisting of a
principal ingredient and a curing agent which are mixed immediately prior
to use. Later, there was prepared a so-called one-package film forming
material having a higher workability.
It was found that a composition which can be stored in one-package form for
a long time and later form a film which exhibits excellent resistance to
dust is obtained by the use of methyltrimethoxysilane as the hydrolyzable
silane. However, methyltrimethoxysilane has a rather low boiling point,
and boils at a still lower temperature with methanol, which is a
hydrolyzate thereof, in the azeotropic form. Therefore, there still
remained a problem that excess methyltrimethoxysilane needed to be added
to form an excellent film outdoors where air flow is much more frequent
because of volatilization of the methyltrimethoxysilane, although the
corresponding film forming material forms an excellent film in a closed
room.
It is an object of the invention to provide a one-package dustproof film
forming material without such disadvantages as described above.
As the result of my research, it was found that a film forming material
which provides an excellent film when cured outdoors where air flow is
much more frequent than in the case of curing in a closed room, can be
prepared by adding an organotin compound as a curing catalyst to a mixture
of alkyd resin and methyltrimethoxysilane, adding water to the resulting
mixture to thereby induce condensation, and then removing the formed
methanol from the reaction product.
SUMMARY OF THE INVENTION
There is provided by the present invention a curable dustproof film forming
material comprising
(A) 100 parts by weight of an alkyd resin
(B) 5 to 200 parts by weight of methyltrimethoxysilane
(C) a curing catalyst; and
(D) 50 to 5000 parts by weight of a solvent mixture consisting of
(a) a volatile organosilicon compound which has a boiling point of
70.degree. to 250.degree. C. at atmospheric pressure and is represented by
one of the following formulae:
(R.sup.1).sub.4 Si, (R.sup.2).sub.3 SiO[(R.sup.3).sub.2 SiO].sub.m
Si(R.sup.2).sub.3,
R.sup.4 Si[OSi(R.sup.5).sub.3 ].sub.3 and [(R.sup.6).sub.2 SiO].sub.n
wherein R.sup.1 to R.sup.6 respectively represent the same or different
alkyl groups, m represents O or a positive integer and n represents a
positive integer of 3 or above and
(b) a hydrocarbon solvent substantially free of methanol, wherein the
amount of (a) is 5 to 95 wt % of the total amount of (a) and (b).
DESCRIPTION OF THE INVENTION
The present invention provides a dustproof film forming material which
comprises:
a cured material prepared by partial condensation of
(A) 100 parts by weight of an alkyd resin
(B) 5 to 200 parts by weight of methyltrimethoxysilane
(C) a curing catalyst; and
(D) 50 to 5000 parts by weight of a solvent mixture consisting of
(a) a volatile organosilicon compound which has a boiling point of 70 to
250.degree. C. at atmospheric pressure and has a formula selected from the
group consisting of
(R.sup.1).sub.4 Si, (R.sup.2).sub.3 Sio[(R.sup.3).sub.2 SiO].sub.m
Si(R.sup.2).sub.3,
R.sup.4 Si[OSi(R.sup.5).sub.3 ].sub.3 and [(R.sup.6).sub.2 SiO].sub.n
wherein R.sup.1 to R.sup.6 present the same or different alkyl groups
respectively, m represents O or a positive integer and n represents a
positive integer of 3 or more and
(b) a hydrocarbon solvent substantially free of methanol wherein the amount
of (a) is 5 to 95 wt % of the total amount of (a) and (b).
The component (A) used in the invention is an essential component to
prepare a dustproof film forming material, and is formed by esterification
or transesterification between a polyhydric alcohol and a polybasic acid,
an anhydride or alkyl ester thereof.
As the polyhydric alcohol, any of conventional aliphatic polyhydric
alcohols, alicyclic polyhydric alcohols or aliphatic polyhydric alcohols
having aromatic rings may be used. Examples thereof are ethylene glycol,
diethylene glycol, triethylene glycol, propylene glycol, butanediol-1,4,
glycerol, trimethylolpropane, diglycerol, pentaerythritol, sorbitol,
cyclohexanediol-1,4, hydrogenated bisphenol A and
2,2-bis(4-hydroxypropoxybenzene). Examples of suitable polybasic acids are
succinic acid, adipic acid, azelaic acid, sebacic acid, fumaric acid,
maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic
acid, trimellitic acid, pyromellitic acid and hexahydrophthalic acid.
Examples of suitable polybasic anhydrides are succinic anhydride, maleic
anhydride, phthalic anhydride, trimellitic anhydride and pyromellitic
anhydride. Examples of suitable alkyl ester are the corresponding methyl
esters and ethyl esters.
In order to form reticulate molecules by esterification or
transesterification thereby affording a cured film, it is desirable that
at least one of these components is a polyhydric alcohol, polybasic acid
or derivative thereof having a functionality of 3 or more. Monovalent
fatty acids such as lauric acid, palmitic acid, stearic acid, oleic acid,
linolic acid, linolenic acid, ricinoleic acid, palm oil fatty acid,
safflower oil fatty acid, linseed oil fatty acid, soybean oil fatty acid,
rosin acid, dehydrated castor oil fatty acid or the like, or melamine
resins may be added as a modifier, if necessary. In order to form a film
having excellent dust resistance, which is the object of the invention, it
is preferable to use a polybasic acid or derivative thereof which contains
at least 50 wt % of phthalic acid, isophthalic acid, phthalic anhydride or
methyl esters thereof. Furthermore, it is preferable to use a room
temperature curable alkyd resin which has an oil length of at least 45%
and is prepared by adding a drying or semi-drying oil as a modifier to a
polyhydric alcohol such as glycerol or a combination of glycerol and
ethylene glycol.
The component (B) is used in the present invention to form a network
siloxane structure upon curing to afford the excellent properties, i.e.
water repellency, high-temperature resistance, weatherability and
low-temperature resistance, characteristic of silicones to the film and to
induce adhesion between said film and the silicone elastomer. The use of
methyltrimethoxysilane as component (B) brings about a film forming
material which forms a film having better dustproofness as compared with
those obtained by using other hydrolyzable silanes or siloxanes and can be
stored for a long time in a one-package form.
The component (B) should be used in an amount of 5 to 200 parts by weight
per 100 parts by weight of the alkyd resin component (A). When component
(B) is used in an amount smaller than 5 parts by weight, the resulting
film exhibits poor weatherability, high-temperature resistance,
water-repellency etc., as well as a lower adhesion to silicone elastomers.
On the other hand, when component (B) is used in an amount larger than 200
parts by weight, the resulting film exhibits a poor anti-fouling property.
The component (C) is used in the present invention to accelerate the
condensation of component (B) and any alcoholic hydroxyl groups which
remain in the alkyd resin (A), and the partial condensation in the
presence of added water to form the coating composition. In addition, it
also functions as an accelerator for curing the coating film when it is
exposed to the atmosphere. Examples of such a catalyst are carboxylic acid
salts of manganese, cobalt, tin, zinc or the like; carboxylic acid disalts
of dialkyltin such as dibutyltin diacetate, dibutyltin dioctoate, or
dibutyltin dilaurate; and dibutyltin oxide.
The component (D) used in the present invention comprises (a) a volatile
organosilicon compound and (b) a hydrocarbon solvent, and is necessary to
provide an excellent wetting property and evenness when the film forming
material is applied to the surface of silicone elastomers.
The volatile orgnosilicon compound (a) is a silane or siloxane which should
not contain any unstable groups, although the presence of hydrogen atoms
bonded to the silicon atom is permissible, and exhibits a certain
volatility, in other words, has a boiling point of 70.degree. to
250.degree. at atmospheric pressure. If the boiling point is lower than
the range specified above, the compound (a) would be dispersed in an early
stage of application by volatilization, thereby affording an
unsatisfactory result. On the other hand, if the boiling point is above
said range, the compound (a) would be hard to dry, thereby slowing down
the rate of film formation. Examples of suitable compounds are silanes
such as triethylsilane, dimethyldiethylsilane, or trimethylbutylsilane;
straight-chain siloxanes such as hexamethyldisiloxane,
octamethyltrisiloxane, decamethyltetrasiloxane, or
dodecamethylpentasiloxane; branchedchain siloxanes such as
3-trimethylsiloxy-1,1,1,3,5,5,5-heptamethyltrisiloxane; cyclic siloxanes
such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane,
decamethylcyclopentasiloxane, or
1-ethyl-3,3,5,5,7,7-hexamethylcyclotetrasiloxane. In particular, it is
desirable to use methylsiloxanes which can be readily prepared. It is
preferable to use oxtamethylcyclotetrasiloxane, which exhibits an
appropriate volatility.
Examples of the hydrocarbon solvent (b) are benzene, toluene, xylene,
n-hexane, n-heptane, cyclohexane, and gasoline. In particular, it is
preferable to use toluene or xylene, which exhibits an appropriate
volatility and solubility of the component (A) and is easy to treat.
The component (A) should be blended in an amount of 5 to 95 wt % of the
total amount of (a) and (b), and preferably in an amount of 10 to 80 wt %.
When the amount of (a) is smaller than 5 wt %, the wetting property of the
film forming material to a silicone elastomer would be lowered thereby
inducing cissings and unevenness. On the other hand, when the amount of
(a) is larger than 95 wt %, the deposited component (A) would make it
impossible to obtain a homogeneous composition.
The component (D) should be blended in an amount of 50 to 5000 parts by
weight per 100 parts by weight of the component (A). When the amount of
(D) is smaller than 50 parts by weight, the high viscosity of the film
forming material would lower its workability. On the other hand, when the
amount of (D) is larger than 5000 parts by weight, multiple coating is
necessary to obtain the desired thickness thereby lowering the workability
as well.
Although it is possible to use lower alcohols in addition to hydrocarbon
solvents, it is necessary to remove said alcohols in the stage of the
production of the film forming material of the invention. It is desirable
to remove the lower alcohols as completely as possible.
Examples of such a lower alcohol are straight-chain or branched aliphatic
alcohols having 1 to 10 carbon atoms, such as methanol, ethanol, n-propyl
alcohol, isopropyl alcohol, sec-butyl alcohol, tert-butyl alcohol, n-amyl
alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 3-pentanol,
n-hexanol, ethylamyl alcohol, and n-heptanol.
By "no methanol or lower alcohol is contained" or "substantially free of
methanol" is meant in this specification that these alcohols have been
removed from the material to such an extend that can be achieved by an
ordinary, simple method.
A process for preparing the film forming material of the invention
comprises the following stages. In the first place, to a solution mixture
consisting of components (A), (B) and (C) which is prepared, for example,
by adding (B) and (C) to a solution of an alkyd resin in a hydrocarbon
solvent, 0.25 to 1.5 mol of water is added per mol of the
methyltrimethoxxysilane (B) thereby effecting partial condensation. At
this stage, it is desirable to use water as a mixture with a lower alcohol
such as methanol, ethanol, or isopropyl alcohol in order to improve the
dispersibility in the solution mixture. The same hydrocarbon solvents as
described above can be used to dissolve the alkyd resin.
When water is added in an amount smaller than 0.25 mol per mol of the
methyltrimethoxysilane, excess methyltrimethoxysilane is present in the
monomer form in the film forming material. The methyltrimethoxysilane has
a rather lower boiling point (i.e. 102.degree. C.) and boils at a still
lower temperature (i.e. 47.5.degree. C.) with methanol, which is the
hydrolyzate thereof, in the azeotropic form, so that it is liable to
disperse by volatilization during drying after application. As outer walls
of buildings where such film forming materials are mainly used are exposed
to ample quantities of air streams, a considerable amount of
methyltrimethoxysilane is lost by dispersion, thereby lowering the
weatherability and water repellency of the film and losing the adhesion to
silicone elastomers. On the other hand, when water is added in an amount
of larger than 1.5 mol, the viscosity would increase during preparation to
thereby make it hard to afford a homogeneous composition.
In addition, it is advantageous for affording a homogeneous, glossy film
forming material to complete the reaction between alcoholic hydroxyl
groups remaining in the alkyd resin and methyltrimethoxysilane by heating
the solution mixture of (A), (B) and (C) to the reflux temperature of the
solvent, methyltrimethoxysilane or a mixture thereof in the azeotropic
form, prior to the partial condensation by the addition of water.
The condensation is usually carried out at 50.degree. to 150.degree. C.,
and preferably at 60 .degree. to 120.degree. C. The reaction time is
usually 0.5 to 9 hours, and preferably 1 to 3 hours.
Then the methanol, which is a lower alcohol obtained as a reaction product,
is removed simultaneously with or after the condensation. It may be
removed by any conventional method such as distillation, extraction, or
adsorption. However, distillation is the most desirable method for
convenience. Distillation is carried out under reduced or atmospheric
pressure, with the distillation temperature set to a point which is higher
than the boiling point of methanol under the distillation pressure. When a
lower alcohol is used as a solvent for water for the partial condensation,
it is desirable to distill it with methanol. Because the presence of
methanol, which is the reaction product, or other lower alcohols which are
used as a solvent for water in the film forming material would bring about
cissings when said material is applied on the surface of a silicone
elastomer so that it is impossible to form the desired homogeneous film.
In such a case, the distilling point is set to a temperature which is
higher than the highest boiling point of corresponding lower alcohols.
Finally, a volatile organosilicon compound (D) is added in the necessary
amount as described above, thereby completing the preparation. If
necessary, the viscosity may be adjusted by adding a hydrocarbon solvent
at this stage. Examples of the hydrocarbon solvent are the same ones as
described above. When a lower alcohol is used, it is necessary to distill
it off again.
Alternately, it is possible to prepare the film forming material of the
present invention by adding component (D) to the mixture obtained from the
above condensation, then removing the lower alcohol. The same removal
methods and distillation conditions as described above may also be applied
in this case.
The film forming material of the present invention can be stored in
one-package form for a long time and affords a dry surface by rapid curing
when applied, thereby forming a homogeneous film which exhibits excellent
dustproofness and weatherability. Therefore, the film forming material of
the present invention is particularly suitable as a top coating for a
silicone elastomer coating material which is applied on the outer walls of
buildings where it is important to maintain an appropriate appearance.
The invention will be more clearly understood with reference to the
following examples, wherein all parts are expressed by weight.
FORMULATION 1
To 200 parts of a 50% toluene solution of an alkyd resin which had been
prepared from a raw material consisting of phthalic anhydride,
pentaerythritol and linseed oil fatty acid in a weight ratio of 25:30:45,
0.1 part of zinc octanoate and 100 parts of titanium oxide were added and
dispersed by using a ball mill. The result composition was termed "A-1".
FORMULATION 2
To 200 parts of a 50% toluene solution of an alkyd resin which had been
prepared from a raw material consisting of terephthalic acid, glycerol and
linolic acid in a weight ratio of 35:25:40, 0.1 part of cobalt naphthenate
and 100 parts of titanium oxide were added and dispersed by using a ball
mill. The resulting composition was termed "A-2".
FORMULATION 3
To 200 parts of a 50% toluene solution of an alkyd resin which had been
prepared from a raw material consisting of isophthalic acid, glycerol and
linseed oil fatty acid in a weight ratio of 30:25:45, 0.1 part of tin
naphthenate and 100 parts of titanium oxide were added and dispersed by
using a ball mill. The resulting composition was termed "A-3".
REFERENTIAL EXAMPLE 1
100 parts of polydimethylsiloxane blocked with silanol groups at both
terminals and having a viscosity of 20,000 cst at 25.degree. C., 10 parts
of fumed silica which had been surface treated with
octamethylcyclotetrasiloxane, 10 parts of titanium oxide and 100 parts of
ground limestone were mixed in a kneading machine, thereby forming a base
compound. Then 0.25 part of dibutyltin dilaurate and 4 parts of
methyltris(butanone oxime)silane were added to said base compound
successively and mixed under moisture-shielding conditions. 100 parts of
kerosene were added to the mixture and mixed, followed by application with
a brush on a mild steel sheet. After being cured for 7 days at room
temperature, the thickness of the silicone elastomer layer turned out to
be approximately 0.4 mm. The resulting steel sheet coated with the
silicone elastomer was termed "Test Plate-1".
REFERENTIAL EXAMPLE 2
100 parts of polydimethylsiloxane blocked with silanol groups at both
terminals and having a viscosity of 5,000 cst at 25.degree. C., 65 parts
of ground limestone and 10 parts of titanium oxide were mixed to form a
base compound. Then 3.0 parts of a crosslinking agent mixture consisting
of 93 wt % of
##STR1##
was added to said base compound. Further, 100 parts of xylene was added to
liquify the mixture, followed by application with a brush on the surface
of a glass plate to form a coating of approximately 0.5 mm in thickness.
Then it was cured for 7 days at room temperature. The resulting glass
plate coated with the silicone elastomer was termed "Test Plate-2".
EXAMPLE 1
300 parts of "A-1", methyltrimethoxysilane and dibutyltin dilaurate in
amounts (parts) as specified in Table 1 were homogeneously mixed in a
flask. Then a mixture of water and methanol in amounts (parts) as
specified in Table 1 was added thereto and the mixture was stirred for 30
mins. at room temperature and, subsequently for 30 mins. at reflux
temperature using a reflux condenser. The temperature of the solution
during reflux was 69.degree. C. Then the solution was cooled to a
temperature which was lower than the reflux temperature, and methanol was
distilled off after replacing the condenser by a distillation tube. At
this stage, the temperature of gas in the flask showed a steep rise. When
it reached 80.degree. C., the heating was ceased to thereby complete the
distillation. Then the solution was cooled to room temperature. The
volatile siloxanes as shown in Table 1 were added to the solution to
afford samples Nos. 11 to 15.
The resulting samples were applied on the surface of "Test Plate-1" and
their wetting properties were observed. Then the time required until they
became dry to the touch was measured while blasting with a blower thereby
adjusting air stream on the surface of samples to approximately 2 m/sec at
room temperature. After blasting for 24 hours, the blasting was ceased and
the samples were cured for 5 days at the same temperature. After the
completion of the curing, adhesion of the film forming materials to the
silicone elastomer was measured by a tensile test with test plates as
known to those skilled in the art. The results are shown in Table 1.
Test plates in the same form as described above were exposed to outdoors to
determine the degree of contamination in Munsell value. The results are
also shown in Table 1, wherein Sample No. 16 is a Comparative Example
which was prepared without partial condensation of methyltrimethoxysilane,
Sample No. 18 is a Comparative Example which contained no
methyltrimethoxysilane and Sample No. 17 is a Comparative Example which
contained no volatile organosilicon compound. In addition, a "Test
Plate-1" which was coated with no sample was exposed at the same time as a
control.
TABLE 1
__________________________________________________________________________
Sample No.
No-
17 coat-
16 (Compara-
18 ing
(Comparative
tive Exam-
(Comparative
(Com.
Component (part) 11 12 13 14 15 Example)
ple) Example)
Exam.)
__________________________________________________________________________
Methyltrimethoxysilane
15 30 50 30 30 30 30 -- --
Dibutyltin dilaurate
0.5 0.5 0.5 0.5 0.5 0.5 0.5 -- --
1:9 mixture of water and methanol
15 30 50 30 30 -- 30 -- --
[(CH.sub.3).sub.2 SiO].sub.4
100 100 100 -- -- 100 -- 100 --
(CH.sub.3).sub.3 SiOSi(CH.sub.3).sub.3
-- -- -- 100 -- -- -- -- --
(CH.sub.3).sub.3 SiOSi(CH.sub.3).sub.2 OSi(CH.sub.3).sub.3
-- -- -- -- 100 -- -- -- --
Xylene -- -- -- -- -- -- 75 -- --
Wetting property good good
good
good
good
good many good --
cissings
Adhesion of
Adhesive strength
10.4 10.5
9.9 10.6
10.2
1.7 -- liable
--
sample film
kgf/cm.sup.2 release
to silicone
Failure cohesive
Same
Same
Same
Same
release of
-- release
--
elastomer failure
as the
as the
as the
as the
sample film sample film
of silicone
left
left
left
left
from silicone
from silicone
elastomer elastomer elastomer
Contamina-
Before exposure
9.5 9.5 9.5 9.5 9.5 -- -- -- 9.5
tion outdoors
(Munsell
6 months after
9.0 9.0 9.0 9.0 9.0 -- -- -- 6.0
value) exposure outdoors
12 months after
9.0 9.0 9.0 9.0 9.0 -- -- -- 4.5
exposure outdoors
__________________________________________________________________________
EXAMPLE 2
300 parts of "A-1", methyltrimethoxysilane and dibutyltin dilaurate in
amounts (parts) as specified in Table 1 were homogeneously mixed in a
flask. Then water in amounts (parts) as specified in Table 2 was added at
a rate of one drop per second to the stirred solution while maintaining
the temperature of the solution at 40.degree. to 45.degree. C. by using a
reflux condenser. After completion of the addition of water, the stirring
was continued for an additional 1 hour at the same temperature and then
for 30 mins. with heating. Then the solution was cooled to a temperature
which was lower than the reflux temperature, and methanol was distilled
off after replacing the reflux condenser by a distillation tube. At this
stage, the temperature of gas in the flask showed a steep rise. When it
reached 80.degree. C., the heating was ceased to thereby complete the
distillation. Then the solution was cooled to room temperature, and the
same weight of xylene as that of the removed methanol and the volatile
siloxanes as shown in Table 2 was added to thereby afford the samples
Nos. 21 to 25. The resulting samples were subjected to a tensile test in
the same manner as described in Example 1. The results are shown in Table
2, wherein Sample No. 26 is a Comparative Example which was prepared
without the removal of methanol by distillation nor the addition of xylene
in the same weight as that of removed methanol.
TABLE 2
__________________________________________________________________________
Sample No.
26
Component (Comparative
(part) 21 22 23 24 25 Example)
__________________________________________________________________________
Methyltrimethoxysilane
15 30 50 30 30 30
Dibutyltin dilaurate
0.5 0.5 0.5 0.5 0.5 0.5
Water 1.5 3 5 3 3 3
[(CH.sub.3).sub.2 SiO].sub.4
100 100 100 -- -- 100
(CH.sub.3).sub.3 SiOSi(CH.sub.3).sub.3
-- -- -- 100 -- --
(CH.sub.3).sub.3 SiOSi(CH.sub.3).sub.2 OSi(CH.sub.3).sub.3
-- -- -- -- 100 --
Wetting property
good good good good good uneven
Adhesion
Adhesive strength
11.1 10.5 10.7 11.0 11.2 --
of sample
kgf/cm.sup.2
film to
Failure cohesive failure
cohesive failure
cohesive failure
cohesive failure
cohesive
--ilure
silicone of silicone
of silicone
of silicone
of silicone
of silicone
elastomer elastomer
elastomer
elastomer
elastomer
elastomer
Contamina-
Before exposure
9.5 9.5 9.5 9.5 9.5 --
tion outdoors
(Munsell
6 months after
9.0 9.0 9.0 9.0 9.0 --
value)
exposure outdoors
12 months after
9.0 9.0 9.0 9.0 9.0 --
exposure outdoors
__________________________________________________________________________
EXAMPLE 3
300 parts of "A-2" was used as a phthalic acid resin solution to thereby
afford the Samples Nos. 31 to 38 as shown in Table 3. These samples were
subjected to a tensile test in the same manner as described in Example 1,
using "Test Plate-2" as a silicone elastomer coated test panel. The
results are shown in Table 3, wherein Sample No. 36 is a Comparative
Example which was prepared without the partial condensation of
methyltrimethoxysilane, Sample No. 38 is a Comparative Example which
contained no methyltrimethoxysilane, and Sample No. 37 is a Comparative
Example which contained no volatile organosilicon compound. In addition, a
"Test Panel-2" which was coated with no sample was exposed at the same
time as a control.
TABLE 3
__________________________________________________________________________
Sample No.
36 37 38 No-coat-
(Comparative
(Com.
(Comparative
ing (Com.
Component (part) 31 32 33 34 35 Example)
Example)
Example)
Example)
__________________________________________________________________________
Methyltrimethoxysilane
30 30 30 30 30 30 30 -- --
Dibutyltin dilaurate
0.5 0.5 0.5 0.5 0.5 0.5 0.5 -- --
1:9 mixture of water and methanol
20 30 40 30 30 -- 30 -- --
[(CH.sub.3).sub.2 SiO].sub.4
80 100 120 -- -- 100 -- 100 --
(CH.sub.3).sub.3 SiOSi(CH.sub.3).sub.3
-- -- -- 100 -- -- -- -- --
(CH.sub.3).sub.3 SiOSi(CH.sub.3).sub.2 OSi(CH.sub.3).sub.3
-- -- -- -- 100 -- -- -- --
Xylene -- -- -- -- -- -- 75 -- --
Wetting property good good
good
good
good
good many good --
cissings
Adhesion of
Adhesive strength
12.0 12.9
11.6
12.0
12.3
1.2 -- liable
--
sample film
kgf/cm.sup.2 release
to silicone
Failure cohesive
Same
Same
Same
Same
release of
-- release
--
elastomer failure
as the
as the
as the
as the
sample film sample film
of silicone
left
left
left
left
from silicone
from silicone
elastomer elastomer elastomer
Contamina-
Before exposure
9.5 9.5 9.5 9.5 9.5 -- -- -- 9.5
tion (Munsell
outdoors
value) 6 months after
9.0 9.0 9.0 9.0 9.0 -- -- -- 4.5
exposure outdoors
12 months after
9.0 9.0 9.0 9.0 9.0 -- -- -- 4.0
exposure outdoors
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EXAMPLE 4
300 parts of "A-3" was mixed with methyltrimethoxysilane in amounts (parts)
as specified in Table 4, and the mixture was stirred for 1 hour at the
reflux temperature of the methyltrimethoxysilane. Then the solution was
cooled to room temperature, treated in the same manner as described in
Example 2 and subjected to a tensile test in the same manner as described
in Example 1. The results are shown in Table 4 , wherein Sample No. 46 is
a Comparative Example which was prepared without the removal of methanol
by distillation nor the addition of xylene in the same weight as that of
removed methanol.
TABLE 4
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Sample No.
46
Component (Comparative
(part) 41 42 43 44 45 Example)
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Methyltrimethoxysilane
30 30 30 30 30 30
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