U.S. patent application number 12/279447 was filed with the patent office on 2009-07-16 for curable composition.
Invention is credited to Noriko Noro, Toshihiko Okamoto, Katsuyu Wakabayashi.
Application Number | 20090182099 12/279447 |
Document ID | / |
Family ID | 38371457 |
Filed Date | 2009-07-16 |
United States Patent
Application |
20090182099 |
Kind Code |
A1 |
Noro; Noriko ; et
al. |
July 16, 2009 |
CURABLE COMPOSITION
Abstract
The present invention has its object to provide a curable
composition which comprises an amidine compound as a non-organotin
catalyst and shows good elongation, flexibility, surface
curability, depth curability and adhesiveness; the above object can
be achieved by a non-organotin curable composition which comprises:
(A) an organic polymer containing a silyl group capable of
crosslinking under siloxane bond formation, the silyl group being a
group represented by the general formula (1): --SiR.sup.1X.sub.2;
(B) an amidine compound (B-1) as a silanol condensation catalyst;
and (C) a carboxylic acid, wherein the ratio between the number of
moles (b) of all nitrogen atoms in the (B-1) component of the
composition and the number of moles (c) of all carboxyl groups in
the (C) component of the composition, namely the ratio (b)/(c), is
higher than 2.
Inventors: |
Noro; Noriko; (Hyogo,
JP) ; Wakabayashi; Katsuyu; (Osaka, JP) ;
Okamoto; Toshihiko; (Osaka, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W., SUITE 800
WASHINGTON
DC
20037
US
|
Family ID: |
38371457 |
Appl. No.: |
12/279447 |
Filed: |
February 9, 2007 |
PCT Filed: |
February 9, 2007 |
PCT NO: |
PCT/JP2007/052419 |
371 Date: |
December 10, 2008 |
Current U.S.
Class: |
525/474 |
Current CPC
Class: |
C08K 5/31 20130101; C09K
3/1018 20130101; C08L 71/02 20130101; C09J 133/14 20130101; C08L
101/10 20130101; C09D 201/10 20130101; C08G 65/336 20130101; C08K
5/0016 20130101; C08L 2666/22 20130101; C09J 133/14 20130101; C08L
2666/22 20130101 |
Class at
Publication: |
525/474 |
International
Class: |
C08L 83/00 20060101
C08L083/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 16, 2006 |
JP |
2006-039241 |
Feb 16, 2006 |
JP |
2006-039243 |
Feb 21, 2006 |
JP |
2006-044565 |
Feb 21, 2006 |
JP |
2006-044566 |
May 10, 2006 |
JP |
2006-=1232021 |
Claims
1. A non-organotin curable composition which comprises: (A) an
organic polymer containing a silyl group capable of crosslinking
under siloxane bond formation, said silyl group being a group
represented by the general formula (1): --SiR.sup.1X.sub.2 (1)
(wherein R.sup.1 represents a group selected from among alkyl
groups containing 1 to 20 carbon atoms, aryl groups containing 6 to
20 carbon atoms, aralkyl groups containing 7 to 20 carbon atoms and
triorganosiloxy groups represented by (R').sub.3SiO-- in which R'
is a hydrocarbon group containing 1 to 20 carbon atoms, the three
R' groups may be the same or different, and X represents a hydroxyl
group or a hydrolyzable group and the two X groups may be the same
or different); (B) an amidine compound (B-1) as a silanol
condensation catalyst; and (C) a carboxylic acid, wherein the ratio
between the number of moles (b) of all nitrogen atoms in the (B-1)
component of the composition and the number of moles (c) of all
carboxyl groups in the (C) component of the composition, namely the
ratio (b)/(c), is higher than 2.
2. The curable composition according to claim 1, wherein a main
chain skeleton of the (A) component organic polymer contains at
least one atom selected from among a hydrogen atom, a carbon atom,
a nitrogen atom, an oxygen atom and a sulfur atom.
3. The curable composition according to claim 1, wherein the (A)
component organic polymer comprises at least one species selected
from the group consisting of polyoxyalkylene polymers, saturated
hydrocarbon polymers and (meth)acrylate ester polymers.
4. The curable composition according to claim 3, wherein the
polyoxyalkylene polymer is a polyoxypropylene polymer.
5. The curable composition according to claim 1, which contains the
(B-1) component in an amount of 0.001 to 20 parts by weight per 100
parts by weight of the component (A).
6. A sealant which comprises the curable composition according to
claim 1.
7. An adhesive which comprises the curable composition according to
claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to a curable composition which
comprises an organic polymer containing a silicon atom-bound
hydroxyl or hydrolyzable group and containing a silyl group capable
of crosslinking under siloxane bond formation (hereinafter referred
to as a "reactive silyl group").
BACKGROUND ART
[0002] It is known that organic polymers containing at least one
reactive silyl group in the molecule have properties such that they
are crosslinked under siloxane bond formation resulting from
hydrolysis and other reactions of the reactive silyl group due to
moisture and the like, even at room temperature to give rubber-like
cured products.
[0003] Among these reactive silyl group-containing polymers, those
polymers which have a polyoxyalkylene type or polyisobutylene type
main chain skeleton are disclosed in Patent Document 1, Patent
Document 2 and the like and have already been produced industrially
and are in wide use in such fields as sealants, adhesives and
coatings.
[0004] Curable compositions to be used in preparing sealants,
adhesives, coatings and like compositions as well as rubber-like
cured products obtained by curing thereof are required to have
various characteristics such as curability, adhesiveness,
mechanical characteristics and storage stability.
[0005] Since moisture in the air causes curing of curable
compositions comprising such a reactive silyl group-containing
organic polymer as mentioned above, a great difference tends to
arise between the curability of the composition inside (depth
curability) and the surface curability. In particular, in the case
of one-pack type curable compositions containing no moisture
therein, a marked difference tends to arise between depth
curability and surface curability. Generally desired are curable
compositions showing rapid curability not only in the surface layer
but also in the depths.
[0006] For obtaining cured products from a curable composition
comprising a reactive silyl group-containing organic polymer, a
silanol condensation catalyst is used. Generally used as the
silanol condensation catalyst are organotin type catalysts having a
carbon-tin bond such as dibutyltin bis(acetylacetonate), since they
render the composition excellent in both surface curability and
depth curability simultaneously and cause rapid increase in initial
strength of cured products obtained. In recent years, however, the
toxicity of organotin type compounds have been pointed out and
development of non-organotin catalysts has been looked for.
[0007] Patent Document 3, Patent Document 4 and Patent Document 5
disclose, as silanol condensation catalysts, catalyst systems
comprising a combination of an amine compound and a carboxylic
acid. However, curable compositions using the non-organotin type
silanol condensation catalysts described in the above-cited patent
documents are sometimes insufficient in surface curability and,
further, tend to decrease in adhesiveness with the increasing
addition level of carboxylic acid.
[0008] On the other hand, while the technology of preparing a
non-organotin type silanol condensation catalyst by using an amine
compound and the carboxylic acid mentioned above in combination,
there are only a relatively small number of examples disclosing a
catalyst system in which an amine compound is used alone. Patent
Document 6 discloses a technology which uses an aryl
group-substituted biguanide compound, such as 1-(o-tolyl)biguanide,
as a silanol condensation catalyst. As the description in the
example section in Patent Document 6 discloses that cure was
effected over such a long period as one week, it is difficult to
attain any practical level of curability with a catalyst system
using an amine compound alone.
[0009] On the other hand, investigations have also been carried out
to improve the curability of compositions by modifying the
structure of reactive silyl group-containing organic polymers. For
example, Patent Document 7 discloses a curable composition
containing an organic polymer terminating in a reactive silyl group
having three hydroxyl or hydrolyzable groups (such silyl group
hereinafter referred to also as a "T terminal group"), for example
a trialkoxysilyl group, and it is disclosed that such a T terminal
group-containing organic polymer, when an organotin type catalyst
is used as a silanol condensation catalyst, shows higher activity
as compared with an organic polymer terminating in a reactive silyl
group containing two hydroxyl or hydrolyzable groups (such silyl
group hereinafter referred to also as a "D terminal group", for
example a dialkoxysilyl group.
[0010] As shown above, it is a task very high in degree of
difficulty to develop a curable composition satisfactory in all of
such practical characteristics as surface curability, depth
curability and adhesiveness using a non-organotin type silanol
condensation catalyst while retaining the elongation and
flexibility of cured products obtained therefrom; under the
existing circumstances, however, early development of such
composition is earnestly awaited.
[0011] Patent Document 1: Japanese Kokai Publication S52-73998
[0012] Patent Document 2: Japanese Kokai Publication S63-6041
[0013] Patent Document 3: Japanese Kokai Publication H05-117519
[0014] Patent Document 4: Japanese Kokai Publication
2001-342363
[0015] Patent Document 5: WO 04/31300
[0016] Patent Document 6: Japanese Kokai Publication
2005-248175
[0017] Patent Document 7: WO 98/47939
SUMMARY OF THE INVENTION
[0018] It is an object of the present invention to provide a
curable composition which comprises a reactive silyl
group-containing organic polymer and an amidine compound as a
non-organotin catalyst and shows good elongation, flexibility,
surface curability, depth curability and adhesiveness.
[0019] The present inventors made intensive investigations to
accomplish the above object and, as a result, found that when use
is made of a D terminal group-containing organic polymer (A), an
amidine compound (B-1) as a silanol condensation catalyst (B) and a
carboxylic acid (C) for increasing the catalytic activity and,
further, when the ratio between the number of moles (b) of all
nitrogen atoms in the component (B-1) contained in the composition
and the number of moles (c) of all carboxyl groups in the component
(C) contained in the composition, namely the ratio (b)/(c), is
higher than 2, a curable composition having good elongation,
flexibility, surface curability, depth curability and adhesiveness
can be obtained in spite of the catalyst being a non-organotin
catalyst. Based on this finding, the present invention has now been
completed.
[0020] That is, the present invention relates to a non-organotin
curable composition, which comprises:
(A) an organic polymer containing a silyl group capable of
crosslinking under siloxane bond formation, the silyl group being a
group represented by the general formula (1):
--SiR.sup.1X.sub.2 (1)
(wherein R.sup.1 represents a group selected from among alkyl
groups containing 1 to 20 carbon atoms, aryl groups containing 6 to
20 carbon atoms, aralkyl groups containing 7 to 20 carbon atoms and
triorganosiloxy groups represented by (R').sub.3SiO-- in which R'
is a hydrocarbon group containing 1 to 20 carbon atoms, the three
R' groups may be the same or different, and X represents a hydroxyl
group or a hydrolyzable group and the two X groups may be the same
or different); (B) an amidine compound (B-1) as a silanol
condensation catalyst; and (C) a carboxylic acid,
[0021] wherein the ratio between the number of moles (b) of all
nitrogen atoms in the (B-1) component of the composition and the
number of moles (c) of all carboxyl groups in the (C) component of
the composition, namely the ratio (b)/(c), is higher than 2.
[0022] One preferred embodiment relates to the above-mentioned
curable composition, wherein a main chain skeleton of the (A)
component organic polymer contains at least one atom selected from
among a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen
atom and a sulfur atom.
[0023] One further preferred embodiment relates to the
above-mentioned curable composition, wherein the (A) component
organic polymer comprises at least one species selected from the
group consisting of polyoxyalkylene polymers, saturated hydrocarbon
polymers and (meth)acrylate ester polymers.
[0024] One further preferred embodiment relates to the
above-mentioned curable composition, wherein the polyoxyalkylene
polymer is a polyoxypropylene polymer.
[0025] One further preferred embodiment relates to the
above-mentioned curable composition, which contains the (B-1)
component in an amount of 0.001 to 20 parts by weight per 100 parts
by weight of the component (A).
[0026] Preferred as applications of the curable composition
according to the present invention is a sealant or an adhesive
which comprises the curable composition as described above.
[0027] The present invention provides a curable composition which
comprises a reactive silyl group-containing organic polymer and in
which an amidine compound is used as a non-organotin catalyst and
which is excellent in elongation, flexibility, surface curability,
depth curability and adhesiveness.
DETAILED DESCRIPTION OF THE INVENTION
[0028] In the following, the present invention is described in
detail.
[0029] The present invention includes a non-organotin type curable
composition which comprises a specific reactive silyl
group-containing organic polymer, a specific silanol condensation
catalyst and a carboxylic acid. The "non-organotin type curable
composition", so referred to herein, is defined as a composition in
which the addition level of an organotin compound is not higher
than 50% by weight in the compound components each acting as a
silanol condensation catalyst.
[0030] In the composition, a D terminal group-containing organic
polymer (A) is used as a reactive silyl group-containing organic
polymer, an amidine compound (B-1) as a silanol condensation
catalyst (B) and a carboxylic acid (C) as a catalytic activity
enhancer and the ratio between the number of moles (b) of all
nitrogen atoms in the (B-1) component contained in the composition
and the number of moles (c) of all carboxyl groups in the (C)
component contained in the composition, namely the ratio (b)/(c),
is higher than 2.
[0031] The curable composition of the invention comprises, as an
essential constituent (A), a reactive silyl group-containing
organic polymer (hereinafter referred to also as "component (A)",
"reactive silyl group-containing organic polymer (A)" or "organic
polymer (A)").
[0032] The organic polymer (A) has, on an average, at least one
reactive silyl group per molecule. The reactive silyl group, so
referred to herein, is an organic group containing hydroxyl groups
or hydrolyzable groups each bound to a silicon atom. The reactive
silyl group-containing organic polymer (A) is crosslinked under
siloxane bond formation as a result of a reaction promoted by a
silanol condensation catalyst.
[0033] As the reactive silyl group, there may be mentioned groups
represented by the general formula (1):
--SiR.sup.1X.sub.2 (1)
(R.sup.1 is at least one group selected from the group consisting
of groups selected from among alkyl groups containing 1 to 20
carbon atoms, aryl groups containing 6 to 20 carbon atoms, aralkyl
groups containing 7 to 20 carbon atoms and triorganosiloxy groups
represented by (R').sub.3SiO-- in which each R' is a hydrocarbon
group containing 1 to 20 carbon atoms and the three R' groups may
be the same or different, and two X groups are independently a
hydroxyl group or a hydrolyzable group).
[0034] The organic polymer, which terminates in a reactive silyl
group represented by the general formula (1) and contains two X
groups (each being a hydroxyl group or a hydrolyzable group) bound
to the silicon atom, is superior in elongation, flexibility and
storage stability to an organic polymer which terminates in a
reactive silyl group containing three X groups (each being a
hydroxyl group or a hydrolyzable group) bound to the silicon
atom.
[0035] The curable composition of the present invention, which
comprises a reactive silyl group-containing organic polymer (A) as
the main component, is better in compatibility with the silanol
condensation catalyst, namely the amidine compound (B-1), as
compared with a composition which comprises, as the main component,
such an inorganic polymer as polydimethylsiloxane, hence is
preferred.
[0036] The curable composition comprising an organic polymer (A) is
excellent in curability and the cured products obtained therefrom
are characterized by excellent adhesiveness.
[0037] Further, for the same reasons, the organic polymer (A)
preferably has a main chain skeleton containing at least one atom
selected from among a hydrogen atom, a carbon atom, a nitrogen
atom, an oxygen atom and a sulfur atom.
[0038] The main chain skeleton of the organic polymer (A) is not
particularly restricted but includes, polyoxyalkylene type polymers
such as polyoxyethylene, polyoxypropylene, polyoxybutylene,
polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymers
and polyoxypropylene-polyoxybutylene copolymers; ethylene-propylene
type copolymers; polyisobutylene, copolymers of isobutylene and
isoprene or the like, polychloroprene, polyisoprene, copolymers of
isoprene or butadiene and acrylonitrile and/or styrene or the like;
polybutadiene and copolymers of isoprene or butadiene and
acrylonitrile and styrene or the like; hydrocarbon type polymers
such as hydrogenated polyolefin polymers derived from these
polyolefin type polymers by hydrogenation; polyester type polymers
obtained by condensation of a dibasic acid such as adipic acid and
a glycol, or ring-opening polymerization of a lactone (s);
(meth)acrylate ester polymers obtained by radical polymerization of
such a compound as ethyl (meth)acrylate and butyl (meth)acrylate;
vinyl polymers obtained by radical polymerization of such a
compound as a (meth)acrylate ester compound, vinyl acetate,
acrylonitrile and styrene; graft polymers obtained by polymerizing
a vinyl compound in such polymers as mentioned above; polysulfide
type polymers; polyamide type polymers such as polyamide 6 produced
by ring-opening polymerization of .epsilon.-caprolactam, polyamide
6.6 produced by polycondensation of hexamethylenediamine and adipic
acid, polyamide 6.10 produced by polycondensation of
hexamethylenediamine and sebacic acid, polyamide 11 produced by
polycondensation of .epsilon.-aminoundecanoic acid, polyamide 12
produced by ring-opening polymerization of
.epsilon.-aminolaurolactam, and copolymer polyamides composed of a
plurality of the polyamides mentioned above; polycarbonate type
polymers such as polycarbonates produced by polycondensation of
bisphenol A and carbonyl chloride; diallyl phthalate type polymers;
and like organic polymers.
[0039] Preferred among those mentioned above are organic polymers
(A) having, as the main chain skeleton, saturated hydrocarbon type
polymers such as polyisobutylene, hydrogenated polyisoprene and
hydrogenated polybutadiene, polyoxyalkylene type polymers,
(meth)acrylate ester polymers and polysiloxane type polymers, in
view of their relatively low glass transition temperature and of
good low-temperature resistance of cured products obtained
therefrom.
[0040] The glass transition temperature of the reactive silyl
group-containing organic polymer (A) is not particularly restricted
but preferably is not higher than 20.degree. C., more preferably
not higher than 0.degree. C., most preferably not higher than
-20.degree. C. When the glass transition temperature is higher than
20.degree. C., the viscosity of the curable composition increases
in the winter season or in cold districts, developing a tendency
toward lowered workability and, further, the flexibility of cured
products obtained decreases and the elongation thereof tends to
decrease.
[0041] The glass transition temperature mentioned above can be
determined by DSC measurement according to the method prescribed in
JIS K 7121.
[0042] A curable composition comprising, as the main component, a
saturated hydrocarbon type polymer and an organic polymer whose
main chain skeleton is a polyoxyalkylene type polymer and a
(meth)acrylate ester polymer is more preferred since, when it is
used as an adhesive or sealant, low-molecular-weight components
scarcely migrate to (i.e. stain) adherends.
[0043] Further, an organic polymer whose main chain skeleton is a
polyoxyalkylene type polymer and a (meth)acrylate ester polymer is
particularly preferred since it is high in moisture permeability
and, when used as a main component of a one-pack type adhesive or
sealant, it is excellent in depth curability and gives cured
products excellent in adhesiveness. Most preferred is an organic
polymer whose main chain skeleton is a polyoxyalkylene type
polymer.
[0044] The polyoxyalkylene type polymer to be used as the main
chain skeleton of the organic polymer (A) is a polymer having a
repeating unit represented by the general formula (2):
--R.sup.4--O-- (2)
(R.sup.4 is a straight or branched alkylene group containing 1 to
14 carbon atoms).
[0045] The group R.sup.4 in the general formula (2) is not
particularly restricted but may be any of the straight or branched
alkylene groups containing 1 to 14 carbon atoms and, among those,
straight or branched alkylene groups containing 2 to 4 carbon atoms
are preferred.
[0046] The repeating unit defined by the general formula (2) is not
particularly restricted but includes, for example, --CH.sub.2O--,
--CH.sub.2CH.sub.2O--, --CH.sub.2CH(CH.sub.3) O--,
--CH.sub.2CH(C.sub.2H.sub.5) O--, --CH.sub.2C(CH.sub.3).sub.2O--
and --CH.sub.2CH.sub.2CH.sub.2CH.sub.2O--.
[0047] The polyoxyalkylene type polymer may have one repeating unit
species or a plurality of repeating unit species. In the case of
use in the field of sealants and the like, in particular, an
organic polymer (A) in which the main component of the main chain
skeleton is a propylene oxide polymer is preferred since such
polymer is noncrystalline and relatively low in viscosity.
[0048] A method of producing such a polyoxyalkylene type polymer is
not particularly restricted but may be any of the methods known in
the art. For example, mention may be made of the method using an
alkali catalyst such as KOH, the method disclosed in Japanese Kokai
Publication S61-215623 which uses, as a catalyst, a transition
metal-porphyrin complex, such as a complex obtained by reacting an
organoaluminum compound with porphyrin, the methods disclosed in
Japanese Kokoku Publications S46-27250 and S59-15336 and U.S. Pat.
Nos. 3,278,457, 3,278,458, 3,278,459, 3,427,256, 3,427,334 and
3,427,335, among others, which use, as a catalyst, a composite
metal cyanide complex, the method disclosed in Japanese Kokai
Publication H10-273512 which uses, as a catalyst, a polyphosphazene
salt, and the method disclosed in Japanese Kokai Publication
H11-060722 which uses, as a catalyst, a phosphazene compound.
[0049] The method of producing a reactive silyl group-containing
polyoxyalkylene type polymer is not particularly restricted but may
be any of the methods known in the art. For example, mention may be
made of the methods disclosed in Japanese Kokoku Publications
S45-36319 and S46-12154, Japanese Kokai Publications S50-156599,
S54-6096, S55-13767, S55-13468 and S57-164123, Japanese Kokoku
Publication H03-2450 and U.S. Pat. Nos. 3,632,557, 4,345,053,
4,366,307 and 4,960,844, among others, and the methods disclosed in
Japanese Kokai Publications S61-197631, S61-215622, S61-215623,
S61-218632, H03-72527, H03-47825 and H08-231707, among others,
according to which polymers high in molecular weight (number
average molecular weight of 6,000 or higher) and narrow in
molecular weight distribution (Mw/Mn of 1.6 or below) can be
obtained.
[0050] In formulating the curable composition using the reactive
silyl group-containing polyoxyalkylene type polymer mentioned
above, the polymer may comprise a single species or a combination
of a plurality of species thereof.
[0051] The saturated hydrocarbon type polymer to be used as the
main chain skeleton of the organic polymer (A) is a polymer whose
molecules are substantially free of any carbon-carbon unsaturated
bond, except for an aromatic ring, and is excellent in heat
resistance, weather resistance, durability and a moisture barrier
property.
[0052] The saturated hydrocarbon type polymer is not particularly
restricted but there may be mentioned (i) polymers derived from an
olefin compound containing 2 to 6 carbon atoms, such as ethylene,
propylene, 1-butene and isobutylene as the repeating unit species,
(ii) polymers derived from a diene type compound, such as butadiene
and isoprene as the repeating unit species, and (iii) polymers
obtained by copolymerizing the above-mentioned diene type compound
and the above-mentioned olefin type compound, followed by
hydrogenation. Among these, isobutylene type polymers and
hydrogenated polybutadiene type polymers are preferred in view of
ease of functional-group introduction into an end thereof, ease of
molecular weight control and adjustability of the number of
terminal functional groups, among others; isobutylene type polymers
are more preferred.
[0053] The isobutylene type polymer may be such one that all of the
repeating units are derived from isobutylene or a copolymer with
another compound. When the isobutylene type copolymer is used as
the main chain skeleton, the polymer preferably has an
isobutylene-derived repeating unit content, in each molecule, of
not lower than 50% by weight, more preferably not lower than 80% by
weight, particularly preferably 90 to 99% by weight, so that the
cured products obtained may have excellent rubber
characteristics.
[0054] A method of producing the saturated hydrocarbon type polymer
is not particularly restricted but may be any of various
conventional polymerization methods. Among them, the living
polymerization method the development of which has been remarkable
in recent years is preferred and, for example, the Inifer
polymerization found by Kennedy et al. (J. P. Kennedy et al., J.
Polymer Sci., Polymer Chem. Ed., 1997, 15, p. 2843) may be
mentioned as a method of producing isobutylene-based polymers using
the living polymerization method. This polymerization method
enables introduction of various functional groups into molecular
ends and the isobutylene type polymers obtained are known to have a
molecular weight of about 500 to 100,000 with a molecular weight
distribution of not broader than 1.5.
[0055] A method of producing the reactive silyl group-containing
saturated hydrocarbon polymer is not particularly restricted but
may be any of the methods known in the art, for example the methods
disclosed in Japanese Kokoku Publications H04-69659 and H07-108928,
Japanese Kokai Publications S63-254149, S64-22904 and H01-197509
and Japanese Patents Nos. 2539445 and 2873395 and Japanese Kokai
Publication H07-53882.
[0056] In formulating the curable composition using the
above-mentioned reactive silyl group-containing saturated
hydrocarbon type polymer, the polymer may comprise a single species
or a combination of a plurality of species thereof.
[0057] A (meth)acrylate ester polymer to be used as the main chain
skeleton of the organic polymer (A) is a polymer in which the
repeating unit is derived from a (meth)acrylate ester compound. The
expression "(meth)acrylate ester" refers to an acrylate ester
and/or a methacrylate ester and has the same meaning also in the
description which follows.
[0058] The (meth)acrylate ester compound to be used as the
repeating unit is not particularly restricted but includes such
(meth)acrylate compounds as (meth)acrylic acid, methyl
(meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate,
isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl
(meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate,
n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl
(meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl
(meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl
(meth)acrylate, phenyl (meth)acrylate, toluoyl (meth)acrylate,
benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate,
3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate,
2-hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, glycidyl
(meth)acrylate, .gamma.-(methacryloyloxypropyl)trimethoxysilane,
.gamma.-(methacryloyloxypropyl)dimethoxymethylsilane, (meth)acrylic
acid-ethylene oxide adducts, trifluoromethylmethyl (meth)acrylate,
2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl
(meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl
(meth)acrylate, perfluoroethyl (meth)acrylate, trifluoromethyl
(meth)acrylate, bis(trifluoromethylmethyl) (meth)acrylate,
2-trifluoromethyl-2-perfluoroethylethyl (meth)acrylate,
2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl
(meth)acrylate and 2-perfluorohexadecylethyl (meth)acrylate.
[0059] The (meth)acrylate ester polymer includes copolymers of a
(meth)acrylate ester compound and a vinyl compound copolymerizable
therewith. The vinyl compound is not particularly restricted but
includes: styrene compounds such as styrene, vinyltoluene,
.alpha.-methylstyrene, chlorostyrene, and styrenesulfonic acid and
salts thereof; silyl group-containing vinyl compounds such as
vinyltrimethoxysilane and vinyltriethoxysilane; maleic acid, maleic
anhydride, and maleic acid monoalkyl esters and dialkyl esters;
fumaric acid and fumaric acid monoalkyl esters and dialkyl esters;
maleimide type compounds such as maleimide, methylmaleimide,
ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide,
octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide
and cyclohexylmaleimide; nitrile group-containing vinyl compounds
such as acrylonitrile and methacrylonitrile; amide group-containing
vinyl compounds such as acrylamide and methacrylamide; vinyl esters
such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl
benzoate and vinyl cinnamate; alkenes such as ethylene and
propylene; conjugated dienes such as butadiene and isoprene; vinyl
chloride, vinylidene chloride, allyl chloride and allyl alcohol. It
is also possible to use a plurality of these as copolymerization
components.
[0060] Among the (meth)acrylate ester polymers obtained from the
compounds mentioned above, those organic polymers which comprise,
as the main chain skeleton, a copolymer of a styrene compound and a
(meth)acrylate compound are preferred since they give cured
products excellent in physical properties; those organic polymers
which comprise, as the main chain skeleton, a copolymer of an
acrylate ester compound and a methacrylate ester compound are more
preferred, and those organic polymers which comprise, as the main
chain skeleton, a polymer of an acrylate ester compound are
particularly preferred.
[0061] For use in general architectural fields, the curable
composition is required to be low in viscosity, while the cured
products obtained therefrom are required to be low in modulus and
high in elongation, weather resistance and thermal stability.
[0062] More preferred as ones meeting these requirements are
organic polymers (A) whose main chain skeleton is derived from a
butyl acrylate compound.
[0063] On the other hand, for use in automotive or like fields, the
cured products obtained are required to be excellent in oil
resistance.
[0064] More preferred as one giving cured products excellent in oil
resistance is an organic polymer (A) whose main chain skeleton is a
copolymer mainly derived from ethyl acrylate.
[0065] Curable compositions comprising the organic polymer (A)
whose main chain skeleton is an ethyl acrylate-based copolymer tend
to give cured products somewhat inferior in low-temperature
characteristics (low-temperature resistance) in spite of their
being excellent in oil resistance. For improving the
low-temperature characteristics, replacement is made of a part of
ethyl acrylate with butyl acrylate. Since, however, an increased
proportion of butyl acrylate tends to impair the good oil
resistance, the proportion thereof is preferably not higher than
40%, more preferably not higher than 30%, in cases of a field where
oil resistance is required.
[0066] The use, as a comonomer component, of 2-methoxyethyl
acrylate or 2-ethoxyethyl acrylate which has an oxygen atom
introduced into the side chain alkyl group is also preferred for
improving low-temperature characteristics and the like without
causing decrease in oil resistance.
[0067] Since, however, the introduction of an alkoxy group having
an ether bond in the side chain tends to render the cured products
obtained inferior in thermal stability, the proportion thereof is
preferably not higher than 40% in cases of use where thermal
stability is required.
[0068] As mentioned above, it is possible to obtain an organic
polymer (A) whose main chain skeleton is an ethyl acrylate-based
copolymer and which is suited for various uses or can meet
requirements by selecting the comonomer component species and
varying the proportion thereof taking into consideration such
physical properties as oil resistance, thermal stability and low
temperature characteristics as required of the cured products
obtained. For example, there may be mentioned, without any
limitative meaning, copolymers of ethyl acrylate, butyl acrylate
and 2-methoxyethyl acrylate copolymer (weight ratio:
40-50/20-30/30-20) as examples excellent in balance among such
physical properties as oil resistance, thermal stability and
low-temperature characteristics.
[0069] In the practice of the present invention, these preferred
compounds may be copolymerized and, further, block-copolymerized
with another compound and, on such occasion, the content of these
preferred compounds is preferably not lower than 40% by weight.
[0070] A method of producing the (meth)acrylate ester polymer is
not particularly restricted but may be any of the methods known in
the art. Among them, the living radical polymerization method is
preferably used in particular in view of the ease of high-rate
introduction of a crosslinking functional group into a molecular
chain end and the possibility of obtaining polymers narrow in
molecular weight distribution and low in viscosity.
[0071] The polymers obtained by ordinary free radical
polymerization using, for example, an azo compound or peroxide as a
polymerization initiator tend to show an increased molecular weight
distribution value generally not lower than 2 and an increased
level of viscosity.
[0072] Among the methods of producing (meth)acrylate ester polymers
using the above-mentioned "living radical polymerization method",
the "atom transfer radical polymerization method" which uses an
organic halide or sulfonyl halide compound as an initiator and a
transition metal complex as a catalyst is preferred as the method
of producing (meth)acrylate ester polymers containing a specific
functional group since it has not only such characteristics of the
"living radical polymerization" as the narrowness in molecular
weight distribution and the capability to give polymers low in
viscosity but also a high degree of freedom in selecting the
initiator and catalyst and the capability to provide the polymers
with a halogen or the like at ends thereof relatively advantageous
to functional-group exchange reactions.
[0073] As for the atom transfer radical polymerization method,
there may be mentioned, for example, the method described in
Matyjaszewski et al., Journal of the American Chemical Society (J.
Am. Chem. Soc.), 1995, 117, p. 5614.
[0074] A method of producing the reactive silyl group-containing
(meth)acrylate ester polymer is not particularly restricted but
includes, for example, the free radical polymerization method using
a chain transfer agent, as disclosed in Japanese Kokoku
Publications H03-14068 and H04-55444 and Japanese Kokai Publication
H06-211922, the atom transfer radical polymerization method
disclosed in Japanese Kokai Publication H09-272714, and the
like.
[0075] It is also possible to use a (meth)acrylate ester copolymer
derived from a plurality of the (meth)acrylate ester compounds
mentioned above as the main chain skeleton of the organic polymer
(A).
[0076] As typical examples of the (meth)acrylate ester copolymer
derived from a plurality of (meth)acrylate ester compounds, there
may be mentioned copolymers whose main chain skeleton substantially
comprises: a repeating unit having an alkyl group containing 1 to 8
carbon atoms as represented by the general formula (3):
--CH.sub.2--C(R.sup.5)(COOR.sup.6)-- (3)
(R.sup.5 is a hydrogen atom or a methyl group and R.sup.6 is an
alkyl group containing 1 to 8 carbon atoms); and a repeating unit
having an alkyl group containing 9 or more carbon atoms as
represented by the general formula (4):
--CH.sub.2--C(R.sup.5)(COOR.sup.7)-- (4)
(R.sup.5 is as defined above referring to the general formula (3)
and R.sup.7 is an alkyl group containing 9 or more carbon
atoms).
[0077] The group R.sup.6 in the general formula (3) is not
particularly restricted but may be any of the alkyl groups
containing 1 to 8 carbon atoms, for example a methyl group, an
ethyl group, a propyl group, an n-butyl group, a t-butyl group and
a 2-ethylhexyl group; among these, alkyl groups containing 1 to 4
carbon atoms are preferred.
[0078] The group R.sup.6 contained in the copolymers is not always
restricted to a single alkyl group species.
[0079] The group R.sup.7 in the general formula (4) is not
particularly restricted but may be any of the alkyl groups
containing 9 or more carbon atoms, for example a lauryl group, a
dodecyl group, a cetyl group, a stearyl group and a behenyl group.
Among these, alkyl groups containing 10 to 30 carbon atoms are
preferred and long-chain alkyl groups containing 10 to 20 carbon
atoms are more preferred.
[0080] The group R.sup.7 contained in the copolymers is not always
restricted to a single alkyl group species.
[0081] The (meth)acrylate ester copolymer substantially comprises
the repeating units defined by the general formula (3) and general
formula (4). The term "substantially" as used herein means that the
total content of the repeating units defined by the general
formulas (3) and (4) in the copolymer is not lower than 50% by
weight, and the total content of the repeating units defined by the
general formulas (3) and (4) in the copolymer is preferably not
lower than 70%.
[0082] The content ratio between the repeating units of general
formulas (3) and (4) occurring in the copolymer as expressed in
terms of the weight ratio (general formula (3): general formula
(4)) is preferably 95:5 to 40:60, more preferably 90:10 to
60:40.
[0083] The (meth)acrylate ester copolymer comprises a copolymer of
(meth)acrylate ester compounds used as the repeating units defined
by the general formulas (3) and (4) and a vinyl compound
copolymerizable therewith.
[0084] As the vinyl compound, there may be mentioned, for example,
acrylic acids such as acrylic acid and methacrylic acid; amide
group-containing compounds such as acrylamide, methacrylamide,
N-methylolacrylamide and N-methylolmethacrylamide, epoxy
group-containing compounds such as glycidyl acrylate and glycidyl
methacrylate, amino group-containing compounds such as
diethylaminoethyl acrylate, diethylaminoethyl methacrylate and
aminoethyl vinyl ether; and, further, such compounds as
acrylonitrile, styrene, .alpha.-methylstyrene, alkyl vinyl ethers,
vinyl chloride, vinyl acetate, vinyl propionate and ethylene.
[0085] These reactive silyl group-containing organic polymers may
be used singly or in combination of two or more species. More
specifically, it is also possible to use an organic-polymer blend
comprising two or more species selected from the group consisting
of reactive silyl group-containing polyoxyalkylene type polymers,
reactive silyl group-containing saturated hydrocarbon type polymers
and reactive silyl group-containing (meth)acrylate ester
polymers.
[0086] A method of producing the organic polymer blend comprising a
reactive silyl group-containing polyoxyalkylene type polymer and a
reactive silyl group-containing (meth) acryl ester polymer is not
particularly restricted but there may be mentioned, for example,
the methods disclosed in Japanese Kokai Publications S59-122541,
S63-112642, H06-172631 and H11-116763, and the like.
[0087] The organic-polymer blend comprising a reactive silyl
group-containing saturated hydrocarbon type polymer and a reactive
silyl group-containing (meth)acrylate ester polymer is not
particularly restricted but mention may be made of the polymers
disclosed in Japanese Kokai Publications H01-168764 and
2000-186176, and the like.
[0088] Further, in addition to those mentioned above, the
organic-polymer blends comprising a reactive silyl functional
group-containing (meth)acrylate ester polymer can also be produced
by a method comprising polymerizing a (meth)acrylate ester monomer
in the presence of a reactive silyl group-containing polymer. This
production method is not particularly restricted but there may be
mentioned, for example, the methods disclosed in Japanese Kokai
Publications S59-78223, S59-168014, S60-228516 and S60-228517.
[0089] In the main chain skeleton of the organic polymer (A), there
may further be present, if necessary, another repeating unit
containing, for example, a urethane bond, so long as the effects of
the present invention are not significantly lessened thereby.
[0090] The urethane bond-containing repeating unit is not
particularly restricted but there may be mentioned, for example, a
repeating unit comprising a group formed by the reaction between an
isocyanato group and an active hydrogen group (the group thus
formed is hereinafter referred to also as an "amide segment").
[0091] The amide segment is an organic group represented by the
general formula (5):
--NR.sup.8--C(.dbd.O)-- (5)
(R.sup.8 is a hydrogen atom or an organic group).
[0092] The amide segment is not particularly restricted but
includes, for example, a urethane group formed by the reaction
between an isocyanato group and a hydroxyl group; a urea group
formed by the reaction between an isocyanato group and an amino
group; and a thiourethane group formed by the reaction between an
isocyanato group and a mercapto group.
[0093] Those organic groups formed by the reaction of an active
hydrogen in the urethane group, the urea group and the thiourethane
group with an isocyanato group also fall within the definition of
"amide segment" as given herein.
[0094] A method of producing the reactive silyl group-containing
organic polymer containing an amide segment in the main chain
skeleton thereof is not particularly restricted but there may be
mentioned, for example, the method comprising reacting an active
hydrogen-terminated organic group-containing organic polymer with
an excess of a polyisocyanate compound to give a polymer having an
isocyanato group at a polyurethane type main chain end and,
thereafter or simultaneously therewith, reacting all or part of the
isocyanato groups in the polymer with a group W in a silicon
compound represented by the general formula (6):
W--R.sup.9--SiR.sup.1X.sub.2 (6)
(R.sup.9 is a divalent organic group, more preferably a divalent
hydrocarbon group containing 1 to 20 carbon atoms; R.sup.1 and the
two X groups are as defined hereinabove referring to the general
formula (1); and W is a group containing at least one active
hydrogen selected from the group consisting of a hydroxyl group, a
carboxyl group, a mercapto group and an amino (primary or
secondary) group), as disclosed in Japanese Kokoku Publication
S46-12154 (U.S. Pat. No. 3,632,557), Japanese Kokai Publications
S58-109529 (U.S. Pat. No. 4,374,237), S62-13430 (U.S. Pat. No.
4,645,816), H08-53528 (EP 0676403), and H10-204144 (EP 0831108),
Japanese Kohyo Publication 2003-508561 (U.S. Pat. No. 6,197,912),
Japanese Kokai Publications H06-211879 (U.S. Pat. No. 5,364,955),
H10-53637 (U.S. Pat. No. 5,756,751), H11-100427, 2000-169544,
2000-169545 and 2002-212415, Japanese Patent 3,313,360, U.S. Pat.
Nos. 4,067,844 and 3,711,445, Japanese Kokai Publication
2001-323040, and the like.
[0095] Mention may also be made of a method comprising reacting an
active hydrogen-containing group occurring at an end of an organic
polymer with the isocyanato group of a reactive silyl
group-containing isocyanate compound represented by the general
formula (7):
O.dbd.C.dbd.N--R.sup.9--SiR.sup.1X.sub.2 (7)
(R.sup.9, the two R's and X are as defined above referring to the
general formula (6)), as disclosed in Japanese Kokai Publications
H11-279249 (U.S. Pat. No. 5,990,257), 2000-119365 (U.S. Pat. No.
6,046,270), S58-29818 (U.S. Pat. No. 4,345,053), H03-47825 (U.S.
Pat. No. 5,068,304), H11-60724, 2002-155145 and 2002-249538, WO
03/018658, WO 03/059981, and the like.
[0096] The active hydrogen-terminated group-containing organic
polymer is not particularly restricted but includes, for example,
hydroxyl group-terminated oxyalkylene polymers (polyether polyols),
polyacrylic polyols, polyester polyols, hydroxyl group-terminated
saturated hydrocarbon type polymers (polyolefin polyols), polythiol
compounds and polyamine compounds.
[0097] Preferred among these are those organic polymers whose main
chain skeleton comprises a polyether polyol, polyacrylic polyol and
polyolefin polyol components, since they have a relatively low
glass transition temperature and give cured products excellent in
low-temperature resistance.
[0098] Those organic polymers comprising a polyether polyol
component are low in viscosity, have good workability and give
cured products showing good depth curability and adhesiveness,
hence are particularly preferred. Curable compositions in which an
organic polymer containing a polyacrylic polyol and saturated
hydrocarbon type polymer component are more preferred since they
give cured products having good weather resistance and thermal
stability.
[0099] The polyether polyol preferably has, on an average, at least
0.7 terminal hydroxyl group per molecule.
[0100] The production method thereof is not particularly restricted
but may be any of the methods known in the art, including, for
example, a polymerization method using an alkali metal catalyst,
and a polymerization method of an alkylene oxide using a
polyhydroxy compound containing at least two hydroxyl groups per
molecule as an initiator in the presence of a double metal cyanide
complex or cesium.
[0101] Among the polymerization methods mentioned above, the
polymerization method using a double metal cyanide complex is
preferred since it gives polymers low in degree of unsaturation,
narrow in molecular weight distribution (Mw/Mn) and low in
viscosity, which give cured products excellent in acid resistance
and weather resistance, among others.
[0102] The term "polyacrylic polyol" refers to a polyol whose
skeleton is a (meth)acrylic acid alkyl ester (co)polymer and whose
molecule contains a hydroxyl group.
[0103] As for the production method thereof, the living radical
polymerization method is preferred and the atom transfer radical
polymerization method is more preferred because of capability of
their giving polymers narrow in molecular weight distribution and
possibly low in viscosity. Also preferred is the polymerization
method involving the so-called SGO process in which an acrylic acid
alkyl ester type compound is continuously bulk-polymerized under
high-temperature and high-pressure conditions, as disclosed in
Japanese Kokai Publication 2001-207157. As such a polyacrylic
polyol, there may be mentioned ARUFON UH-2000 (product of Toagosei
Co., Ltd.), and the like.
[0104] The polyisocyanate compound is not particularly restricted
but includes, for example, an aromatic type polyisocyanate such as
toluene (tolylene) diisocyanate, diphenylmethane diisocyanate and
xylylene diisocyanate; and an aliphatic type polyisocyanate such as
isophorone diisocyanate and hexamethylene diisocyanate.
[0105] When the amide segment content is high in the main chain
skeleton of the organic polymer serving as the (A) component in the
practice of the present invention, the organic polymer shows a high
viscosity and sometimes gives a composition poor in workability.
Conversely, the amide segment in the main chain skeleton of the (A)
component tends to improve the curability of the composition
according to the present invention.
[0106] The silicon compound defined by the general formula (6) is
not particularly restricted but there may be mentioned, for
example, amino group-containing silane compounds such as
.gamma.-aminopropyldimethoxymethylsilane,
N-(.beta.-aminoethyl)-.gamma.-aminopropyldimethoxymethylsilane,
.gamma.-(N-phenyl)aminopropyldimethoxymethylsilane,
N-ethylaminoisobutyldimethoxymethylsilane,
N-cyclohexylaminomethyldiethoxymethylsilane,
N-cyclohexylaminomethyldiethoxymethylsilane and
N-phenylaminomethyldimethoxymethylsilane; hydroxyl group-containing
silane compounds such as
.gamma.-hydroxypropyldimethoxymethylsilane; and mercapto
group-containing silane compounds such as
.gamma.-mercaptopropyldimethoxymethylsilane.
[0107] As the silicon compound represented by the general formula
(6), there may further be mentioned Michael addition products
derived from various .alpha.,.beta.-unsaturated carbonyl compounds
and a primary amino group-containing silane compound or Michael
addition products derived from various (meth)acryloyl
group-containing silane compounds and a primary amino
group-containing compound, as disclosed in Japanese Kokai
Publications H06-211879 (U.S. Pat. No. 5,364,955), H10-53637 (U.S.
Pat. No. 5,756,751), H10-204144 (EP 0831108) 2000-169544 and
2000-169545.
[0108] The reactive silyl group-containing isocyanate compound
defined by the general formula (7) is not particularly restricted
but includes, for example, .gamma.-methyldimethoxysilylpropyl
isocyanate, .gamma.-methyldiethoxysilylpropyl isocyanate and
dimethoxymethylsilylmethyl isocyanate.
[0109] As the reactive silyl group-containing isocyanate compound
defined by the general formula (7), there may further be mentioned
the reaction products derived from a silicon compound of the
general formula (6) and an excess of a polyisocyanate compound, as
disclosed in Japanese Kokai Publication 2000-119365 (U.S. Pat. No.
6,046,270).
[0110] The hydrolyzable group represented by X in the general
formula (1) is not particularly restricted but includes those
hydrolyzable groups which are known in the art, for example, a
hydrogen atom, halogen atoms, and an alkoxy group, an acyloxy
group, a ketoxymate group, an amino group, an amide group, an acid
amide group, an aminooxy group, a mercapto group and an alkenyloxy
group. Among these, a hydrogen atom, an alkoxy group, an acyloxy
group, a ketoxymate group, an amino group, an amide group, an
aminooxy group, a mercapto group and an alkenyloxy group are
preferred, and an alkoxy group is more preferred from the
viewpoints of mild hydrolyzability and easy handleability.
[0111] The group R.sup.1 in the general formula (1) is not
particularly restricted but includes, for example, an alkyl group
such as a methyl group and an ethyl group, a cycloalkyl group such
as a cyclohexyl group, an aryl group such as a phenyl group, an
aralkyl group such as a benzyl group, and a triorganosiloxy group
represented by --OSi(R').sub.3 wherein R' is a methyl group, a
phenyl group or the like. Among these, a methyl group is
preferred.
[0112] The reactive silyl group defined by the general formula (1)
is not particularly restricted but includes, for example, a
dimethoxymethylsilyl group, a diethoxymethylsilyl group and a
diisopropoxymethylsilyl group. Among these, a dimethoxymethylsilyl
group is preferred since it has high activity and affords good
curability and good storage stability.
[0113] Further, a diethoxymethylsilyl group is particularly
preferred since the alcohol formed upon hydrolysis reaction of the
reactive silyl group is highly safe ethanol.
[0114] A method of introducing the reactive silyl group is not
particularly restricted but includes such methods known in the art
as the methods (a) to (c) shown below.
(a) A method comprising: reacting a polymer containing such a
functional group as a hydroxyl group in the molecule with an
organic compound containing an active group reactive with this
functional group as well as an unsaturated group to give an
unsaturated group-containing polymer; or copolymerizing a polymer
containing such a functional group as a hydroxyl group in the
molecule with an unsaturated group-containing epoxy compound to
give an unsaturated group-containing polymer, and then reacting the
reaction product obtained with a reactive silyl group-containing
hydrosilane for hydrosilylation. (b) A method comprising reacting
the unsaturated group-containing organic polymer obtained in the
same manner as described above in (a) with a compound containing a
mercapto group and a reactive silyl group. (c) A method comprising
reacting an organic polymer containing such a functional group as a
hydroxyl group, an epoxy group or an isocyanato group in the
molecule with a compound containing a functional group reactive
with this function group and a reactive silyl group.
[0115] Among these methods, the method (a) or the method (c) in
such a mode that a hydroxyl group-terminated polymer is reacted
with a compound containing an isocyanato group and reactive silyl
group is preferred in view of the fact that a high conversion rate
can be attained in a relatively short period of time.
[0116] The method (a) is more preferred since curable compositions
based on the reactive silyl group-containing organic polymer
obtained by the method (a) tends to be lower in viscosity than
curable compositions based on the organic polymer obtained by the
method (c) and, as a result, curable compositions having good
workability can be obtained and, further, the organic polymer
obtained by the method (b) has a stronger mercaptosilane-due odor
as compared with the organic polymer obtained by the method
(a).
[0117] The hydrosilane compound to be used in carrying out the
method (a) is not particularly restricted but includes, for
example, halogenated silanes such as methyldichlorosilane;
alkoxysilanes such as methyldimethoxysilane, methyldiethoxysilane,
and phenyldimethoxysilane; acyloxysilanes such as
methyldiacetoxysilane and phenyldiacetoxysilane; and
ketoxymatesilanes such as bis(dimethylketoxymate)methylsilane and
bis(cyclohexylketoxymate)methylsilane. Among these,
alkoxyhydrosilanes are preferred because of the mild
hydrolyzability and easy handleability of curable compositions
based on the organic polymer (A) obtained and, among the
alkoxyhydrosilanes, methyldimethoxysilane is preferred since
curable compositions based on the organic polymer (A) obtained are
superior in curability and restorability.
[0118] The synthetic method (b) is not particularly restricted but
may be, for example, the method of introducing a mercapto group-
and reactive silyl group-containing compound into an
unsaturated-bond site in the organic polymer by a radical addition
reaction in the presence of a radical initiator and/or a radical
generation source. The mercapto group- and reactive silyl
group-containing compound is not particularly restricted but
includes, for example, .gamma.-mercaptopropylmethyldimethoxysilane,
.gamma.-mercaptopropylmethyldiethoxysilane and
(mercaptomethyl)methyldiethoxysilane.
[0119] The method of reacting a hydroxyl group-terminated polymer
with an isocyanato group- and reactive silyl group-containing
compound according to the synthetic method (c) is not particularly
restricted but may be, for example, a method disclosed in Japanese
Kokai Publication H03-47825. The isocyanato group- and reactive
silyl group-containing compound is not particularly restricted but
includes, for example,
.gamma.-isocyanatopropylmethyldimethoxysilane,
.gamma.-isocyanatopropylmethyldiethoxysilane,
isocyanatomethyldimethoxymethylsilane and
isocyanatomethyldiethoxymethylsilane.
[0120] The reactive silyl group-containing organic polymer (A) to
be used may have either a straight chain structure or a branched
chain structure in the molecule thereof, and the number average
molecular weight thereof, as expressed in terms of the value on a
polystyrene equivalent basis as derived from the value measured by
GPC, is preferably 500 to 100,000, more preferably 1,000 to 50,000,
particularly preferably 3,000 to 30,000. When the number average
molecular weight is lower than 500, the cured products obtained
tend to be inferior in elongation characteristics and, when it is
in excess of 100,000, the resulting curable composition becomes
high in viscosity and tends to be inferior in workability.
[0121] The number of reactive silyl groups contained in each
molecule of the organic polymer (A) is preferably not smaller than
1 on an average; it is preferably 1.1 to 5. When the number of
reactive silyl groups contained in each molecule is smaller than 1
on an average, the curable composition tends to be inferior in
curability and the cured products obtained show a tendency toward
failure to exhibit a good rubber elastic behavior.
[0122] The reactive silyl group may occur at a main chain end or at
a side chain end, or at both. In particular, when the reactive
silyl group occurs only at a main chain end, the effective network
size in the organic polymer component contained in the cured
products obtained becomes increased, so that it becomes easy to
obtain rubber-like cured products showing high strength, high
elongation and low elastic modulus.
[0123] The curable composition according to the present invention
comprises, as essential components, an amidine compound
(hereinafter sometimes referred to as "component (B)" or "amidine
compound (B-1)") as a silanol condensation catalyst (component (B))
and a carboxylic acid (hereinafter sometimes referred to as
"component (C)" or "carboxylic acid (C)") as a promoter (component
(C)).
[0124] By using an amidine compound (B-1) as a silanol condensation
catalyst, in spite of its being a non-organotin catalyst, it
becomes possible for the curable composition according to the
present invention to show a high level of curability that cannot
have been arrived at with the conventional amine compound-based
silanol condensation catalysts known in the art (aliphatic amines,
aromatic amines, etc.) and for the cured products obtained to show
good adhesiveness against various adherends.
[0125] As the conventional amine compound-based silanol
condensation catalysts, there may be mentioned, for example,
aliphatic primary amines such as methylamine, propylamine,
isopropylamine, butylamine, amylamine, 2-ethylhexylamine,
laurylamine, stearylamine and cyclohexylamine; aliphatic secondary
amines such as dimethylamine, dipropylamine, diisopropylamine,
dibutylamine, diamylamine, dioctylamine, bis(2-ethylhexyl)amine,
dilaurylamine, dicetylamine, distearylamine and methylstearylamine;
aliphatic tertiary amines such as triamylamine, trihexylamine and
trioctylamine; aliphatic unsaturated amines such as triallylamine
and oleylamine; aromatic amines such as laurylaniline,
stearylaniline and triphenylamine; and other amines such as
monoethanolamine, diethanolamine, triethanolamine,
3-hydroxypropylamine, diethylenetriamine, triethylenetetramine,
benzylamine, 3-methoxypropylamine, 3-lauryloxypropylamine,
3-dimethylaminopropylamine, 3-diethylaminopropylamine,
xylylenediamine, ethylenediamine, hexamethylenediamine,
triethylenediamine, 2,4,6-tris(dimethylaminomethyl)phenol,
morpholine and N-methylmorpholine.
[0126] The carboxylic acid (C) to be used in combination with the
amidine compound (B-1) plays a role in enhancing the catalytic
activity of the amidine compound (B-1).
[0127] As regards the mixing ratio between the amidine compound
(B-1) and carboxylic acid (C) in the silanol condensation catalyst,
the relation between the number of moles of nitrogen atoms derived
from the amidine compound (B-1) and the number of moles of carboxyl
groups derived from the carboxylic acid (C) is important, and it is
important that the mole ratio between them (number (b) of moles of
all (B-1)-derived nitrogen atoms/number (c) of moles of all
(C)-derived carboxyl groups) be higher than 2 so that curable
compositions showing good surface curability, depth curability and
adhesiveness may be obtained.
[0128] The amidine compound (B-1) is not particularly restricted
but may be any of the amidine compounds known in the art. Among
them, those amidine compounds represented by the general formula
(8) are preferred since they are high in catalytic activity and
provide the organic polymer (A) with good curability.
R.sup.10N.dbd.CR.sup.11--NR.sub.2.sup.12 (8)
(R.sup.10, R.sup.11 and the two R.sup.12s are independently a
hydrogen atom or an organic group. Any two or more of R.sup.10,
R.sup.11 and the two R.sup.12s may be combined together to form a
ring structure.)
[0129] Preferred as R.sup.10 in the general formula (8) is a
hydrogen atom or a hydrocarbon group since, in such a case, the
amidine compound is readily available and can provide the organic
polymer (A) with good curability; more preferred is a hydrocarbon
group in which the carbon atom at position 1 is saturated.
[0130] When R.sup.10 is an organic group or a hydrocarbon group,
the number of carbon atoms therein is preferably 1 to 20, more
preferably 1 to 10, since, in such a case, the organic polymer (A)
can be provided with good curability.
[0131] Preferred as R.sup.11 in the general formula (8) are a
hydrogen atom, a --NR.sub.2.sup.13 group (in which the two
R.sup.13s are independently a hydrogen atom or a hydrocarbon group
containing 1 to 20 carbon atoms), a
--NR.sup.14--C(.dbd.NR.sup.15)--NR.sub.2.sup.16 group (in which
R.sup.14, R.sup.15 and the two R.sup.16s are independently a
hydrogen atom or a hydrocarbon group containing 1 to 20 carbon
atoms), a --N.dbd.C(NR.sub.2.sup.17)--NR.sub.2.sup.18 group (in
which the two R.sup.17 s and the two R.sup.18 s are independently a
hydrogen atom or a hydrocarbon group containing 1 to 20 carbon
atoms) or a hydrocarbon group containing 1 to 20 carbon atoms
since, in such a case, the organic polymer (A) can be provided with
good curability and the cured products obtained show good
adhesiveness; more preferred are a hydrogen atom, a
--NR.sub.2.sup.13 group (R.sup.13 being as defined above), a
--NR.sup.14--C(.dbd.NR.sup.15)--NR.sub.2.sup.16 group (R.sup.14,
R.sup.15 and the two R.sup.16s being as defined above), a
--N.dbd.C(NR.sub.2.sup.17)--NR.sub.2.sup.18 group (the two R.sup.17
s and the two R.sup.18s being as defined above) or a hydrocarbon
group containing 1 to 10 carbon atoms; particularly preferred are a
--NR.sub.2.sup.13 group (R.sup.13 being as defined above), a
--NR.sup.14--C(.dbd.NR.sup.15)--NR.sub.2.sup.16 group (R.sup.14,
R.sup.15 and the two R.sup.16s being as defined above) or a
--N.dbd.C(NR.sub.2.sup.17)--NR.sub.2.sup.18 group (the two
R.sup.17s and the two R.sup.18s being as defined above).
[0132] Those amidine compounds of the general formula (8) in which
R.sup.11 is an --NR.sub.2.sup.13 group or a like organic group are
called guanidine compounds.
[0133] Those amidine compounds of the general formula (8) in which
R.sup.11 is such an organic group as the
--NR.sup.14--C(.dbd.NR.sup.15)--NR.sub.2.sup.56 group and
--N.dbd.C(NR.sub.2.sup.17)--NR.sub.2.sup.18 group mentioned above
are called biguanide compounds.
[0134] Each of the two R.sup.12s in the general formula (8) is
preferably a hydrogen atom or a hydrocarbon group containing 1 to
20 carbon atoms, more preferably a hydrogen atom or a hydrocarbon
group containing 1 to 10 carbon atoms, since, in such a case, the
amidine compound is readily available and can provide the organic
polymer (A) with good curability.
[0135] Since, when R.sup.11 in the general formula (8) is an
--NR.sup.14--C(.dbd.NR.sup.15)--NR.sub.2.sup.16 group (R.sup.14,
R.sup.15 and the two R.sup.16s being as defined above), the cured
products obtained show good adhesiveness, it is preferred that at
least one of R.sup.10, the two R.sup.12s, R.sup.14, R.sup.15 and
the two R.sup.16s be an aryl group.
When R.sup.11 in the general formula (8) is an --NR.sub.2.sup.13
group (R.sup.13 being as defined above), the curability of the
curable composition tends to decrease with the increase in the
number of aryl groups bound to the nitrogen atoms contained in the
molecule and, therefore, it is preferred that at least four of
R.sup.10, the two R.sup.12s and the two R.sup.15s be either an
organic group other than an aryl group or a hydrogen atom.
[0136] In view of their ready availability and their ability to
provide the organic polymer (A) with good curability, those amidine
compounds represented by the general formula (8) in which any two
or more of R.sup.10, R.sup.11 and the two R.sup.12s are bound
together to form a ring structure are preferred, and those cyclic
amidine compounds represented by the general formula (9) are more
preferred.
##STR00001##
[0137] (R.sup.19, R.sup.20 and R.sup.21 are independently a
hydrogen atom or an organic group. R.sup.20 and R.sup.21 may be
bound together to form a ring structure.)
[0138] From the viewpoints of ready availability and ability to
provide the organic polymer (A) with excellent curability, R.sup.19
in the general formula (9) is preferably a divalent hydrocarbon
group containing 1 to 10 carbon atoms, more preferably a divalent
hydrocarbon group containing 1 to 10 carbon atoms in which the
carbon atom at position 1 is saturated, still more preferably a
divalent hydrocarbon group containing 1 to 5 carbon atoms in which
the carbon atom at position 1 is saturated, particularly preferably
a divalent hydrocarbon group containing 2 or 3 carbon atoms in
which the carbon atom at position 1 is saturated. From the
viewpoints of curability and adhesiveness, R.sup.20 is preferably a
hydrogen atom, an --NR.sub.2.sup.13 group (R.sup.13 being as
defined above) or a hydrocarbon group containing 1 to 20 carbon
atoms, more preferably a hydrogen atom, an --NR.sub.2.sup.13 group
(R.sup.13 being as defined above) or a hydrocarbon group containing
1 to 10 carbon atoms, particularly preferably an --NR.sub.2.sup.13
group (R.sup.13 being as defined above). From the viewpoints of
ready availability and ability to provide the organic polymer (A)
with excellent curability, R.sup.21 is preferably a hydrogen atom
or a hydrocarbon group containing 1 to 20 carbon atoms, more
preferably a hydrogen atom or a hydrocarbon group containing 1 to
10 carbon atoms.
[0139] From the viewpoint of ready availability and of ability to
provide the organic polymer (A) with good curability, it is
preferred that R.sup.20 and R.sup.21 be bound together to form a
ring structure.
[0140] The amidine compound (B-1) preferably has a melting point of
not lower than 23.degree. C., more preferably not lower than
50.degree. C., still more preferably not lower than 80.degree. C.,
particularly preferably not lower than 120.degree. C. When the
melting point is lower than 23.degree. C., an amidine compound
(B-1)-derived liquid tends to bleed out, namely flow out onto the
surface of the cured product, causing a problem of soiling one's
hand upon touching of the hand with the cured product surface. The
number of carbon atoms contained in the amidine compound (B-1)
represented by the general formula (8) is preferably not smaller
than 2, more preferably not smaller than 6, particularly preferably
not smaller than 7.
[0141] When the number of carbon atoms is smaller than 2 (namely
when the molecular weight is low), the volatility of the compound
becomes increased, causing a tendency toward pollution of the work
environment. It is not necessary to particularly specify the upper
limit to the number of carbon atoms contained in the amidine
compound (B-1); it is generally preferred, however, that the number
be not larger than 10,000.
[0142] For the same reasons as mentioned above, the amidine
compound (B-1) preferably has a molecular weight of not lower than
60, more preferably not lower than 120, particularly preferably not
lower than 130. It is not necessary to particularly specify the
upper limit to the molecular weight; it is generally preferred,
however, that the molecular weight be not higher than 100,000.
[0143] The amidine compound (B-1) (inclusive of the guanidine
compound and biguanide compound) is not particularly restricted but
includes imidazole compounds such as imidazole, 2-methylimidazole
and 2-ethyl-4-methylimidazole; amidine compounds such as
2-methyl-2-imidazoline, 2-ethyl-2-imidazoline,
2-n-propyl-2-imidazoline, 2-isopropyl-2-imidazoline,
2-n-octyl-2-imidazoline, 4,4-dimethyl-2-imidazoline,
4,5-dimethyl-2-imidazoline, 1-(1-aminoethyl)-2-octyl-2-imidazoline,
2-n-undecyl-2-imidazoline, 2-cyclohexyl-2-imidazoline,
2-benzyl-2-imidazoline, 2-phenyl-2-imidazoline,
2-[(3,4-dichlorophenoxy)methyl]-2-imidazoline,
1,4,5,6-tetrahydropyrimidine,
1,2-dimethyl-1,4,5,6-tetrahydropyrimidine,
1-n-propyl-2-methyl-1,4,5,6-tetrahydropyrimidine,
1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),
6-(dibutylamino)-1,8-diazabicyclo[5.4.0]undec-7-ene (DBA-DBU) and
1,5-diazabicyclo[4.3.0]non-5-ene (DBN); guanidine compounds such as
guanidine, 1,1,2-trimethylguanidine, 1,2,3-trimethylguanidine,
1,1,3,3-tetramethylguanidine, 1,1,2,3,3-pentamethylguanidine,
1-benzylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine,
1,3-diphenylguanidine, 1,3-dibenzylguanidine,
1-benzyl-2,3-dimethylguanidine,
N-(2-imidazolin-2-yl)-1-naphthalenamine,
2-phenyl-1,3-dicyclohexylguanidine, 1-benzylaminoguanidine,
1-(benzyloxy)guanidine,
1,1'-[4-(dodecyloxy)-m-phenylene]bisguanidine, guanylthiourea,
2-[(5,6,7,8-tetrahydronaphthalen-1-yl)amino]-2-imidazoline,
1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD),
7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD),
7-isopropyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene,
7-cyclohexyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene,
7-phenyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene and
2,3,5,6-tetrahydro-3-phenyl-1H-imidazo[1,2-a]imidazole; and
biguanide compounds such as biguanide, 1-methylbiguanide,
1-n-butylbiguanide, 1-(2-ethylhexyl)biguanide,
1-n-octadecylbiguanide, 1,1-dimethylbiguanide,
1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide,
1-phenylbiguanide, 1-(o-tolyl)biguanide (OTBG),
1-(2-chlorophenyl)biguanide, 1-benzylbiguanide, 2-benzylbiguanide,
3-benzylbiguanide, N,N-diamidinoaniline, 1,5-ethylenebiguanide,
1-morpholinobiguanide, 1-(4-chlorobenzyloxy)biguanide,
1-n-butyl-N.sup.2-ethylbiguanide, 1,1'-ethylenebisbiguanide,
1-[3-(diethylamino)propyl]biguanide,
1-[3-(dibutylamino)propyl]biguanide,
N',N''-dihexyl-3,12-diimino-2,4,11,13-tetraazatetradecanedia
midine, 1-(morpholinosulfonyl)benzylbiguanide,
1-(hydroxymethyl)biguanide,
1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidine and
5-[3-(2,4,5-trichlorophenoxy)propoxy]-1-isopropylbiguanide. Either
a single species among these amidine compounds may be incorporated
in the curable composition or a combination of a plurality thereof
may be incorporated in the curable composition.
[0144] Among the amidine compounds mentioned above, biguanide
compounds are preferred since the curable compositions obtained
show good adhesiveness. More specifically, biguanide,
1-n-butylbiguanide, 1,1-dimethylbiguanide, 1-phenylbiguanide and
OTBG are preferred, and OTBG is particularly preferred.
[0145] Such cyclic amidine compounds as 2-methyl-2-imidazoline,
1,2-dimethyl-1,4,5,6-tetrahydropyrimidine, DBU and DBN and such
cyclic guanidine compounds as TBD, MTBD and
7-cyclohexyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene are preferred, and
TBD and MTBD are more preferred, in view of their ability to
provide the organic polymer (A) with good curability.
[0146] From the viewpoint that bleeding out from the cured products
obtained can be inhibited, such amidine compounds having a melting
point of not lower than 23.degree. C. as TBD, 1-phenylguanidine,
1-n-butylbiguanide, 1,1-dimethylbiguanide, 1-phenylbiguanide and
OTBG are preferred, and 1-phenylguanidine and OTBG are more
preferred.
[0147] The carboxylic acid (C) to be used in combination with the
amidine compound (B-1) plays a role in enhancing the catalytic
activity of the amidine compound (B-1) and produces the effect of
improving the surface curability and depth curability of the
curable composition and, at the same time, produces the effect of
improving the adhesiveness of the cured products obtained.
[0148] The carboxylic acid (C) is not particularly restricted but
includes straight-chain saturated fatty acids such as acetic acid,
propionic acid, butyric acid, valeric acid, caproic acid, enanthic
acid, caprylic acid, 2-ethylhexanoic acid, pelargonic acid, capric
acid, undecanoic acid, lauric acid, tridecylic acid, myristic acid,
pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid,
nonadecanoic acid, arachic acid, behenic acid, lignoceric acid,
cerotic acid, montanic acid, melissic acid and lacceric acid;
monoenoic unsaturated fatty acids such as undecylenic acid,
linderic acid, tsuzuic acid, physeteric acid, myristoleic acid,
2-hexadecenoic acid, 6-hexadecenoic acid, 7-hexadecenoic acid,
palmitoleic acid, petroselinic acid, oleic acid, elaidic acid,
asclepic acid, vaccenic acid, gadoleic acid, gondoic acid, cetoleic
acid, erucic acid, brassidic acid, selacholeic acid, ximenic acid,
lumequeic acid, acrylic acid, methacrylic acid, angelic acid,
crotonic acid, isocrotonic acid and 10-undecenoic acid; polyenoic
unsaturated fatty acids such as linoelaidic acid, linolic acid,
10,12-octadecadienoic acid, hiragonic acid, .alpha.-eleostearic
acid, .beta.-eleostearic acid, punicic acid, linolenic acid,
8,11,14-eicosatrienoic acid, 7,10,13-docosatrienoic acid,
4,8,11,14-hexadecatetraenoic acid, moroctic acid, stearidonic acid,
arachidonic acid, 8,12,16,19-docosatetraenoic acid,
4,8,12,15,18-eicosapentaenoic acid, clupanodonic acid, nisinic acid
and docosahexaenoic acid; branched fatty acids such as
1-methylbutyric acid, isobutyric acid, 2-ethylbutyric acid,
isovaleric acid, tuberculostearic acid, pivalic acid,
2,2-dimethylbutyric acid, 2-ethyl-2-methylbutyric acid,
2,2-diethylbutyric acid, 2,2-dimethylvaleric acid,
2-ethyl-2-methylvaleric acid, 2,2-diethylvaleric acid,
2,2-dimethylhexanoic acid, 2,2-diethylhexanoic acid,
2,2-dimethyloctanoic acid, 2-ethyl-2,5-dimethylhexanoic acid,
neodecanoic acid and versatic acid; triple bond-containing fatty
acids such as propiolic acid, tariric acid, stearolic acid,
crepenynic acid, xymenynic acid and 7-hexadecynoic acid; alicyclic
carboxylic acids such as naphthenic acid, malvalic acid, sterculic
acid, hydnocarpic acid, chaulmoogric acid, gorlic acid,
1-methylcyclopentanecarboxylic acid, 1-methylcyclohexanecarboxylic
acid, 2-methylbicyclo[2.2.1]-5-heptene-2-carboxylic acid,
1-adamantanecarboxylic acid, bicycle[2.2.1]heptanes-1-carboxylic
acid and bicycle[2.2.2]octane-1-carboxylic acid; oxygen-containing
fatty acids such as acetoacetic acid, ethoxyacetic acid, glyoxylic
acid, glycolic acid, gluconic acid, sabinic acid,
2-hydroxytetradecanoic acid, ipurolic acid,
2,2-dimethyl-3-hydroxypropionic acid, 2-hydroxyhexadecanoic acid,
jalapinolic acid, juniperic acid, ambrettolic acid, aleuritic acid,
2-hydroxyoctadecanoic acid, 12-hydroxyoctadecanoic acid,
18-hydroxyoctadecanoic acid, 9,10-dihydroxyoctadecanoic acid,
ricinolic acid, camlolenic acid, licanic acid, pheronic acid,
cerebronic acid and
2-methyl-7-oxabicyclo[2.2.1]-5-heptene-2-carboxylic acid; and
halogen-substituted monocarboxylic acids such as chloroacetic acid,
2-chloroacrylic acid and chlorobenzoic acid.
[0149] As far as aliphatic dicarboxylic acids are concerned, there
is no particular restriction and there may be mentioned, for
example saturated dicarboxylic acids such as adipic acid, azelaic
acid, pimelic acid, suberic acid, sebacic acid, ethylmalonic acid,
glutaric acid, oxalic acid, malonic acid, succinic acid,
oxydiacetic acid, dimethylmalonic acid, ethylmethylmalonic acid,
diethylmalonic acid, 2,2-dimethylsuccinic acid, 2,2-diethylsuccinic
acid, 2,2-dimethylglutaric acid and
1,2,2-trimethyl-1,3-cyclopentanedicarboxylic acid; and unsaturated
dicarboxylic acids such as maleic acid, fumaric acid,
acetylenedicarboxylic acid and itaconic acid.
[0150] As far as aliphatic polycarboxylic acids are concerned,
there is no particular restriction and there may be mentioned, for
example, tricarboxylic acids such as aconitic acid,
4,4-dimethylaconitic acid, citric acid, isocitric acid and
3-methylisocitric acid. As aromatic carboxylic acids, there may be
mentioned aromatic monocarboxylic acids such as benzoic acid,
9-anthracenecarboxylic acid, atrolactic acid, anisic acid,
isopropylbenzoic acid, salicylic acid and toluic acid; and aromatic
polycarboxylic acids such as phthalic acid, isophthalic acid,
terephthalic acid, carboxyphenylacetic acid and pyromellitic
acid.
[0151] Either a single species among the carboxylic acid (C) used
in combination with the amidine compound (B-1) may be incorporated
into the curable composition or a combination of a plurality
thereof may be incorporated into the curable composition.
[0152] Among those mentioned above, monocarboxylic acids are more
preferred, and chain monocarboxylic acids are still more preferred,
in view of their good compatibility with the component (A).
[0153] The carboxylic acid (C) preferably has a melting point of
not higher than 65.degree. C., more preferably -50 to 50.degree.
C., particularly preferably -40 to 35.degree. C. When the melting
point of the carboxylic acid is in excess of 65.degree. C., the
handling of the acid becomes difficult and the workability tends to
become worsened.
[0154] The carboxylic acid (C) preferably has 5 to 20 carbon atoms,
more preferably 6 to 18 carbon atoms, particularly preferably 8 to
12 carbon atoms. When the number of carbon atoms is in excess of
20, the acid readily becomes a solid and shows a tendency toward
decreased compatibility with the component (A) and, therefore, the
activity of the curable composition tends to lower. On the other
hand, when the number of carbon atoms is not larger than 5, the
carboxylic acid increases in volatility and tends to emit an odor
at raised levels.
[0155] From the viewpoints of availability and workability, as
mentioned above, 2-ethylhexanoic acid, octylic acid, oleic acid,
naphthenic acid, 2,2-dimethyloctanoic acid,
2-ethyl-2,5-dimethylhexanoic acid, neodecanoic acid and versatic
acid are preferred among others.
[0156] The addition level of the (B-1) component is not
particularly restricted provided that the requirement that the
ratio (b)/(c) value mentioned above is higher than 2 is satisfied.
Preferably, the addition level is 0.01 to 20 parts by weight, more
preferably 0.5 to 15 parts by weight, particularly preferably 1 to
10 parts by weight, per 100 parts by weight of the (A) component
organic polymer.
[0157] When the addition level of the (B-1) component is below 0.01
part by weight, any practical rate of curing may not be obtained in
some instances and, further, sometimes, it becomes difficult for
the curing reaction to proceed to a sufficient extent. On the other
hand, when the addition level of the (B-1) component is in excess
of 20 parts by weight, the pot-life becomes too short, so that the
workability tends to become poor.
[0158] The addition level of the (C) component is not particularly
restricted provided that the requirement that the ratio (b)/(c)
value mentioned above is higher than 2 is satisfied. Preferably,
the addition level is about 0.01 to 20 parts by weight, more
preferably about 0.1 to 10 parts by weight, particularly preferably
about 1 to 7 parts by weight, per 100 parts by weight of the (A)
component organic polymer. When the addition level of the (C)
component is below 0.01 part by weight, any sufficient adhesiveness
may not be obtained in some instances. On the other hand, when the
addition level of the (C) component is in excess of 20 parts by
weight, any practical level of depth curability may not be obtained
in some instance.
[0159] While the curable composition of the present invention uses
an amidine compound as a silanol condensation catalyst, another
silanol condensation catalyst may be used, if necessary, in
combination with the amidine compound so long as the effects of the
present invention will not be reduced.
[0160] The silanol condensation catalyst other than the amidine
compound is not particularly restricted but includes, for example,
carboxylic acid metal salts such as tin carboxylates, lead
carboxylates, bismuth carboxylates, potassium carboxylates, calcium
carboxylates, barium carboxylates, titanium carboxylates, zirconium
carboxylates, hafnium carboxylates, vanadium carboxylates,
manganese carboxylates, iron carboxylates, cobalt carboxylates,
nickel carboxylates and cerium carboxylates; titanium compounds
such as tetrabutyl titanate, tetrapropyl titanate, titanium
tetrakis(acetylacetonate), bis(acetylacetonato)diisopropoxytitanium
and diisopropoxytitanium bis(ethyl acetoacetate); organotin
compounds such as dibutyltin dilaurate, dibutyltin maleate,
dibutyltin phthalate, dibutyltin dioctanoate, dibutyltin
bis(2-ethylhexanoate), dibutyltin bis(methyl maleate), dibutyltin
bis(ethyl maleate), dibutyltin bis(butyl maleate), dibutyltin
bis(octyl maleate), dibutyltin bis(tridecyl maleate), dibutyltin
bis(benzyl maleate), dibutyltin diacetate, dioctyltin bis(ethyl
maleate), dioctyltin bis(octyl maleate), dibutyltin dimethoxide,
dibutyltin bis(nonylphenoxide), dibutenyltin oxide, dibutyltin
oxide, dibutyltin bis(acetylacetonate), dibutyltin bis(ethyl
acetoacetonate), reaction products of dibutyltin oxide-silicate
compound and reaction products of dibutyltin oxide-phthalic acid
ester; aluminum compounds such as aluminum tris(acetylacetonate),
aluminum tris(ethyl acetoacetate) and diisopropoxyaluminum ethyl
acetoacetate; zirconium compounds such as zirconium
tetrakis(acetylacetonate); various metal alkoxides such as
tetrabutoxyhafnium; organic acid phosphoric acid esters; organic
sulfonic acids such as trifluoromethanesulfonic acid and
dodecylbenzenesulfonic acid; inorganic acids such as hydrochloric
acid, phosphoric acid and boronic acid; and so forth.
[0161] The use of such a silanol condensation catalyst other than
an amidine compound in combination with the amidine compound is
expected to enhance the catalytic activity and thus improve the
depth curability and surface curability of the curable composition
and the adhesiveness and other properties of the cured products
obtained. Among those enumerated above, titanium compounds,
aluminum compounds and organic sulfonic acids, among others, are
preferred since the surface curability of the organic polymer (A)
is more enhanced by the use thereof; diisopropoxytitanium bis(ethyl
acetoacetate), diisopropoxyaluminum ethyl acetoacetate and
dodecylbenzenesulfonic acid are more preferred.
[0162] The combined use of titanium compounds is also preferred
since the use gives curable compositions with increased strength
and elongation; among them, diisopropoxytitanium bis(ethyl
acetoacetate) is more preferred. The combined use of sulfonic acids
is preferred since the solubility of the amidine compound (B-1)
into the curable composition is increased thereby; among them,
dodecylbenzenesulfonic acid is more preferred in view of its ready
availability.
[0163] Since, however, when an organotin compound is used in
combination, the toxicity of the curable composition tends to
increase with the increase in organotin addition level, the
addition level of the organotin compound is preferably as low as
possible and, more specifically, it is preferably not higher than 1
part by weight, more preferably not higher than 0.5 part by weight,
particularly preferably not higher than 0.05 part by weight, per
100 parts by weight of the organic polymer (A); substantial absence
thereof is most preferred.
[0164] The organotin compound addition level in the "non-organotin
type curable composition" so referred to herein is such that the
organotin compound amounts to not more than 50% by weight,
preferably not more than 30% by weight, more preferably not more
than 10% by weight, particularly preferably not more than 1% by
weight, of the compound components acting as silanol condensation
catalysts; substantial absence thereof is most preferred. The
curable composition of the present invention is preferably a
non-organotin type curable composition and, from the viewpoints of
toxicity and environmental stress, it is more preferably a tin-free
curable composition containing substantially none of such tin
compounds as organotin type compounds and tin carboxylates, still
more preferably an organotin-free and carboxylic acid metal
salt-free curable composition containing substantially none of
organotin compounds and various carboxylic acid metal salts,
particularly preferably a metal catalyst-free curable composition
containing substantially none of the above-mentioned metal
element-containing curing catalysts such as carboxylic acid metal
salts, titanium compounds, organotin compounds, organoaluminum
compounds and zirconium compounds.
[0165] In cases where a metal compound other than an organotin is
used in combination, the addition level thereof more specifically
is preferably not higher than 5 parts by weight, more preferably
not higher than 2 parts by weight, per 100 parts by weight of the
organic polymer (A), and substantial absence thereof is most
preferred.
[0166] In the curable composition of the present invention, there
may be incorporated a plasticizer if necessary. The plasticizer
functions as an agent for adjusting the viscosity and slump
characteristics of the curable composition and adjusting the
tensile strength, elongation and like mechanical characteristics of
the cured products obtained.
[0167] The plasticizer is not particularly restricted but includes:
phthalic acid esters such as dibutyl phthalate, diheptyl phthalate,
bis(2-ethylhexyl) phthalate and butyl benzyl phthalate; nonaromatic
dibasic acid esters such as dioctyl adipate, dioctyl sebacate,
dibutyl sebacate and isodecyl succinate; aliphatic esters such as
butyl oleate and methyl acetylricinoleate; phosphoric acid esters
such as tricresyl phosphate and tributyl phosphate; trimellitic
acid esters; chlorinated paraffins; hydrocarbon type oils such as
alkyldiphenyls and partially hydrogenated terphenyl; process oils;
and epoxy type plasticizers such as epoxidized soybean oil and
benzyl epoxystearate.
[0168] Addition of a polymeric plasticizer containing a polymer
component in the molecule is preferred since such addition makes it
possible to maintain the initial characteristics of the cured
products obtained for a long period of time and, further, improve
the drying characteristics (also referred to as applicability) of
an alkyd paint when it is applied to the cured products obtained.
The polymeric plasticizer is not particularly restricted but
includes: vinyl polymers obtained by polymerization of vinyl
monomers by various methods; polyalkylene glycol esters such as
diethylene glycol dibenzoate, triethylene glycol dibenzoate and
pentaerythritol esters; polyester type plasticizers derived from a
dibasic acid such as sebacic acid, adipic acid, azelaic acid and
phthalic acid and a dihydric alcohol such as ethylene glycol,
diethylene glycol, triethylene glycol, propylene glycol and
dipropylene glycol; polyether polyols such as polyethylene glycol,
polypropylene glycol and polytetramethylene glycol, each having a
molecular weight of not lower than 500, preferably not lower than
1000, or polyether derivatives derived from such polyether polyols
by esterification or etherification of one or both hydroxyl groups
therein; polystyrenes such as polystyrene and
poly-.alpha.-methylstyrene; polybutadiene, polybutene,
polyisobutylene, butadiene-acrylonitrile copolymers,
polychloroprene and the like.
[0169] Among these polymeric plasticizers, those highly compatible
with the organic polymer (A) are preferred and, for example,
polyethers and vinyl polymers may be mentioned. Polyethers are more
preferred since they provide the curable composition with good
surface curability and depth curability and cause no curing
retardation after storage; more specifically, polypropylene glycol
is particularly preferred.
[0170] Further, vinyl polymers are preferred since they have high
compatibility with the organic polymer (A) and provide the
resulting cured products with good weather resistance and thermal
stability; among them, acrylic polymers and/or methacrylic polymers
are more preferred, and such acrylic polymers as polyacrylic acid
alkyl esters are particularly preferred.
[0171] While the method of producing the polyacrylic acid alkyl
esters is not particularly restricted, the living radical
polymerization method is preferred because of capability of their
giving polymers narrow in molecular weight distribution and
possibly low in viscosity, and the atom transfer radical
polymerization method is more preferred. Also particularly
preferred is the method called "SGO process" and disclosed in
Japanese Kokai Publication 2001-207157, which comprises
continuously bulk-polymerizing an acrylic acid alkyl ester type
compound under high temperature and high pressure conditions.
[0172] The number average molecular weight of the polymeric
plasticizer is generally 500 to 15000, preferably 800 to 10000,
more preferably 1000 to 8000, particularly preferably 1000 to 5000,
most preferably 1000 to 3000. When the molecular weight of the
polymeric plasticizer is too low, the plasticizer may escape from
the cured products obtained with the lapse of time due to heat or
rainfall and, as a result, it becomes no longer possible to
maintain the initial physical characteristics, staining by adhesion
of dust may possibly be caused and the alkyd applicability tends to
become poor. On the other hand, when the molecular weight is
excessively high, the viscosity of the curable composition will
increase and the workability tends to become poor.
[0173] The molecular weight distribution of the polymeric
plasticizer is not particularly restricted but preferably is
narrow, for example narrower than 1.80, preferably not wider than
1.70, more preferably not wider than 1.60, still more preferably
not wider than 1.50, particularly preferably not wider than 1.40,
most preferably not wider than 1.30.
[0174] In the case of polyether type polymers, the number average
molecular weight is determined by the end-group analysis and, in
the case of other polymers, it is determined by the GPC method. The
molecular weight distribution (Mw/Mn) is measured by the GPC method
(on the polystyrene equivalent basis).
[0175] The polymeric plasticizer may be a reactive silyl
group-containing one or a silyl group-free one and, in cases where
a reactive silyl group-containing polymeric plasticizer is added,
the polymeric plasticizer is preferably involved in the curing
reaction and thus, the plasticizer can be prevented from migrating
from the cured products obtained.
[0176] The reactive silyl group-containing polymeric plasticizer is
preferably a compound whose silyl group content is, on an average,
not more than one, preferably not more than 0.8, per molecule. When
a reactive silyl group-containing plasticizer, in particular a
reactive silyl group-containing oxyalkylene polymer, is added, it
is preferred that the number average molecular weight thereof be
lower than that of the organic polymer (A) so that a satisfactory
plasticizing effect may be obtained.
[0177] The plasticizer to be added may comprise a single species or
a combination of a plurality of species. It is also possible to add
a low-molecular-weight plasticizer and a polymeric plasticizer in
combination. The plasticizer addition may also be made on the
occasion of the production of the organic polymer (A).
[0178] When a plasticizer is added, the addition level thereof is
preferably 5 to 150 parts by weight, more preferably 10 to 120
parts by weight, particularly preferably 20 to 100 parts by weight,
per 100 parts by weight of the organic polymer (A). At addition
levels lower than 5 parts by weight, there is a tendency for the
plasticizing effect to be little produced and, at levels exceeding
150 parts by weight, there arises a tendency for the mechanical
strength of the cured products to become insufficient.
[0179] In the curable composition of the present invention, there
may be incorporated an adhesiveness-imparting agent, if
necessary.
[0180] The adhesiveness-imparting agent is a compound containing a
hydrolyzable silyl group and other functional group(s) in the
molecule and, when incorporated into the curable composition,
effectively improves the adhesiveness of the resulting cured
products to various adherends and/or effectively removes
(dehydrates) the moisture contained in the curable composition.
[0181] Further, the adhesiveness-imparting agent is a compound
capable of not only producing the effects mentioned above but also
functioning as a physical property modifier and/or a
dispersibility-improving agent for inorganic fillers.
[0182] The hydrolyzable silyl group occurring in the
adhesiveness-imparting agent may be any of those enumerated
hereinabove as examples of the hydrolyzable group. Among those, a
methoxy group, an ethoxy group, and the like are preferred because
of their proper rate of hydrolysis. The number of hydrolyzable
groups contained in each molecule of the adhesiveness-imparting
agent is preferably not smaller than 2, particularly preferably not
smaller than 3.
[0183] As examples of the functional group other than the
hydrolyzable silyl group as occurring in the adhesiveness-imparting
agent, there may be mentioned a substituted or unsubstituted amino
group, mercapto group, epoxy group, carboxyl group, vinyl group,
isocyanato group and isocyanurate group, and halogen atoms. In
particular, substituted or unsubstituted amino group-containing
adhesiveness-imparting agents are preferred since they show good
compatibility with the guanidine compound (B-1) and the like.
Substituted or unsubstituted amino group-containing
adhesiveness-imparting agents are preferred also in view of their
ability to enhance the adhesiveness between the cured products
obtained and adherends.
[0184] The adhesiveness-imparting agent is not particularly
restricted but includes aminosilanes such as
.gamma.-aminopropyltrimethoxysilane,
.gamma.-aminopropyltriethoxysilane,
.gamma.-aminopropyltriisopropoxysilane,
.gamma.-aminopropylmethyldimethoxysilane,
.gamma.-aminopropylmethyldiethoxysilane,
.gamma.-(2-aminoethyl)aminopropyltrimethoxysilane,
.gamma.-(2-aminoethyl)aminopropylmethyldimethoxysilane,
.gamma.-(2-aminoethyl)aminopropyltriethoxysilane,
7-(2-aminoethyl)aminopropylmethyldiethoxysilane,
7-(2-aminoethyl)aminopropyltriisopropoxysilane,
.gamma.-(2-(2-aminoethyl)aminoethyl)aminopropyltrimethoxysilane,
.gamma.-(6-aminohexyl)aminopropyltrimethoxysilane,
3-(N-ethylamino)-2-methylpropyltrimethoxysilane,
2-aminoethylaminomethyltrimethoxysilane,
N-cyclohexylaminomethyltriethoxysilane,
N-cyclohexylaminomethyldiethoxymethylsilane,
.gamma.-ureidopropyltrimethoxysilane,
.gamma.-ureidopropyltriethoxysilane,
N-phenyl-.gamma.-aminopropyltrimethoxysilane,
N-phenylaminomethyltrimethoxysilane,
N-benzyl-.gamma.-aminopropyltrimethoxysilane,
N-vinylbenzyl-.gamma.-aminopropyltriethoxysilane,
N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole,
N-cyclohexylaminomethyltriethoxysilane,
N-cyclohexylaminomethyldiethoxymethylsilane,
N-phenylaminomethyltrimethoxysilane,
(2-aminoethyl)aminomethyltrimethoxysilane and
N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine; ketimine type
silanes such as
N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, and
condensation products resulting from partial condensation of the
silanes mentioned above.
[0185] Among the adhesiveness-imparting agents mentioned above,
.gamma.-aminopropyltrimethoxysilane is particularly preferred from
the viewpoints of compatibility, transparency and availability.
[0186] The adhesiveness-imparting agent to be incorporated in the
curable composition may comprise a single species or a combination
of a plurality of species. In selecting the adhesiveness-imparting
agent, it is preferred that one containing a hydrolyzable group of
the same structure as the hydrolyzable group occurring in the
organic polymer (A) so that the surface curability of the curable
composition may be prevented from changing during storage. Thus,
when the hydrolyzable silyl group in the organic polymer (A) is a
methoxysilyl group, an adhesiveness-imparting agent with a
methoxysilyl group structure should be selected and, when the
hydrolyzable silyl group in the organic polymer (A) is an
ethoxysilyl group, an adhesiveness-imparting agent with an
ethoxysilyl group structure should be selected.
[0187] To the curable composition of the present invention, there
may be added a filler, if necessary. The filler is not particularly
restricted but includes: reinforcing fillers such as fumed silica,
precipitated silica, crystalline silica, fused silica, dolomite,
silicic anhydride, hydrous silicic acid and carbon black; heavy
calcium carbonate, colloidal calcium carbonate, magnesium
carbonate, diatomaceous earth, calcined clay, clay, talc,
titaniumoxide, bentonite, organicbentonite, ferric oxide, fine
aluminum powder, flint powder, zinc oxide, activated zinc white,
shirasu balloons, glass microballoons, organic microballoons based
on a phenol resin or a vinylidene chloride resin, organic powders
such as PVC powder and PMMA powder; and fibrous fillers such as
asbestos, glass fibers and filaments.
[0188] When a filler is added, the addition level thereof is
preferably 1 to 250 parts by weight, more preferably 10 to 200
parts by weight, per 100 parts by weight of the organic polymer
(A).
[0189] On the occasion of using the curable composition as a
one-pack type adhesive or sealant, it is preferred, for obtaining
good storage stability, that such a filler as mentioned above be
uniformly mixed with a dehydrating agent such as calcium oxide and
the mixture be allowed to stand in a sealed bag made of an airtight
material for a proper period of time for dehydrating and drying,
and then used, as disclosed in Japanese Kokai Publication
2001-181532 and the like.
[0190] When the cured products obtained are to be used in the
fields of application where transparency is required, a polymer
powder containing a polymer of methyl methacrylate and the like,
and noncrystalline silica, are preferred as the filler to be added,
as disclosed in Japanese Kokai Publication H11-302527 and the like;
hydrophobic silica and the like, as disclosed in Japanese Kokai
Publication 2000-38560 and the like, is more preferred.
[0191] The hydrophobic silica, so referred to herein, is a product
derived by treating the surface of the silicon dioxide fine powder
generally occupied by silanol (--SiOH) groups with an organosilicon
halide or an alcohol for conversion of those groups to
(--SiO-hydrophobic) groups. The hydrophobic silica is not
particularly restricted but includes, for example, products
obtained by treating silanol groups occurring on a silicon dioxide
fine powder with dimethylsiloxane, hexamethyldisilazane,
dimethyldichlorosilane, trimethoxyoctylsilane, trimethylsilane, and
the like. The untreated silicon dioxide fine powder whose surface
is occupied by silanol (--SiOH) groups is called hydrophilic silica
fine powder.
[0192] When the cured products obtained are to be used in the
fields of application where high strength is required, silicon
compounds such as fumed silica, precipitated silica, crystalline
silica, fused silica, dolomite, silicic anhydride and hydrous
silicic acid; carbon black, surface-treated finely divided calcium
carbonate, calcined clay, clay, activated zinc white and the like
are preferred as the filler to be added, and the addition level
thereof is preferably 1 to 200 parts by weight per 100 parts by
weight of the organic polymer (A).
[0193] Further, when the cured products obtained are to be used in
the fields of application where low strength and high elongation
modulus are required, titanium oxide, calcium carbonate such as
heavy calcium carbonate, magnesium carbonate, talc, ferric oxide,
zinc oxide and shirasu balloons are preferred as the filler to be
added, and the addition level thereof is preferably 5 to 200 parts
by weight per 100 parts by weight of the organic polymer (A).
[0194] When calcium carbonate is added, the tendency toward
improvements in the breaking strength, breaking elongation and
adhesiveness of the cured products obtained increases as the
specific surface area increases. Only one of these filler species
may be added or a plurality of species thereof may be added in
combination.
[0195] The example of addition of a plurality of additives is not
particularly restricted but the combined use of a surface-treated
fine calcium carbonate and a calcium carbonate larger in particle
diameter such as heavy calcium carbonate is preferred since cured
products excellent in physical characteristics can be obtained.
[0196] Preferred as the surface-treated fine calcium carbonate are
those whose particle diameter is not larger than 0.5 .mu.m and
whose particle surface has been treated with a fatty acid and a
fatty acid salt.
[0197] Preferred as the calcium carbonate having a large particle
diameter are those whose particle diameter is not smaller than 1
.mu.m and whose particle surface has not been treated.
[0198] In cases where the curable composition is required to have
good workability (releasability, etc.) or where the surface of the
cured products obtained is required to be matted, organic balloons
or inorganic balloons are preferred as the filler to be added.
These fillers may be surface-treated or non-surface-treated, and
only one species thereof may be added or a plurality of species
thereof may be added in admixture. For improving the workability
(releasability, etc.), the particle diameter of the balloons is
preferably not larger than 0.1 mm and, for rendering the cured
product surface matted, it is preferably 5 to 300 .mu.m.
[0199] The curable composition of the present invention, which
gives cured products excellent in chemical resistance, is suited
for use, in particular, as a sealant, adhesive or like composition
for siding boards in ceramic and like systems and for housing
outside-wall joints and outside-wall tiles.
[0200] On the occasion of use in such fields of application, the
cured products obtained appear or exist on the joints or like
observable surfaces and, therefore, it is desirable that the cured
product design be in harmony with the outside wall design. In
recent years, in particular, the sputtering coating and the
addition of colored aggregates, among others, have been employed
for providing luxurious outside walls, so that the designs of cured
products are becoming more and more important.
[0201] For obtaining luxurious designs, a scaly or granular
substance is incorporated in the curable composition of the present
invention. The addition of a granular substance gives sandy or
sandstone-like rough surfaces, and the addition of a scaly
substance gives surfaces rendered uneven due to scales.
[0202] The cured products obtained are in harmony with luxurious
outside walls and are excellent in chemical resistance, so that the
luxurious appearance thereof can be maintained for a long period of
time.
[0203] The scaly or granular substance is not particularly
restricted but includes, for example, one disclosed in Japanese
Kokai Publication H09-53063, and the diameter thereof is properly
selected according to the outside wall material and design and is
preferably not smaller than 0.1 mm, more preferably 0.1 to 5.0 mm.
In the case of a scaly substance, the thickness of scales is
preferably 1/10 to 1/5 (0.01 to 1.00 mm) of the diameter.
[0204] The addition level of the scaly or granular substance is
properly selected according to the size of the scaly or granular
substance, the outside-wall material and design and other factors;
preferably, the addition level is 1 to 200 parts by weight per 100
parts by weight of the curable composition.
[0205] The material of the scaly or granular substance is not
particularly restricted but includes natural products such as
silica sand and mica, synthetic rubbers, synthetic resins, and
inorganic materials such as alumina. These may be appropriately
colored according to the outside wall material, design, and so
forth so that the design quality of the composition applied to
joints and so forth may be enhanced.
[0206] Preferred methods of finishing are those disclosed in
Japanese Kokai Publication H09-53063 and the like.
[0207] The scaly or granular substance may be incorporated in
advance in the curable composition or may be admixed with the
curable composition of the occasion of use thereof.
[0208] It is also possible, for the same purposes, to add balloons
(preferably having an average particle diameter of not smaller than
0.1 mm) to the curable composition, thereby providing the resulting
cured product surface with a coarse feel such as a sandy or
sandstone feel and, further, contributing to weight reduction. The
"balloons" are spherical hollow fillers.
[0209] The balloons are not particularly restricted but include,
for example, those disclosed in Japanese Kokai Publications
H10-251618, H02-129262, H04-8788, H04-173867, H05-1225, H07-113073,
H09-53063, 2000-154368 and 2001-164237 and WO 97/05201.
[0210] As the material of balloons, there may be mentioned
inorganic materials such as glass, shirasu and silica; and organic
materials such as phenol resins, urea resins, polystyrene and
Saran. Mention may further be made of composite materials of an
inorganic material and an organic material; and laminates
comprising a plurality of layers. These may be used singly or a
plurality species thereof may be used in combination.
[0211] It is also possible to use balloons subjected to surface
coating treatment, treatment with various surface treatment agents
or some other treatment; as typical examples, there may be
mentioned organic balloons coated with calcium carbonate, talc,
titanium oxide or the like, and inorganic balloons surface-treated
with an adhesiveness-imparting agent.
[0212] Further, the balloons preferably have a particle diameter of
not smaller than 0.1 mm, more preferably 0.2 mm to 5.0 mm,
particularly preferably 0.5 mm to 5.0 mm. When the diameter is
smaller than 0.1 mm, the addition even in large amounts only
increases the viscosity of the composition, sometimes failing to
provide the resulting cured products with a coarse feel.
[0213] When balloons are added, the addition level thereof can be
properly selected according to the intended decorative effect; it
is preferred that balloons having a particle diameter of not
smaller than 0.1 mm be added in an amount such that the volume
concentration thereof in the curable composition amounts to 5 to
25% by volume, more preferably 8 to 22% by volume. When the volume
concentration of balloons is below 5% by volume, the desired coarse
feel tends to become lost. At level exceeding 25% by volume, the
viscosity of the curable composition increases and the workability
thereof tends to become poor; further, the modulus of the cured
products increases and the fundamental performance characteristics
of the sealant or adhesive tend to become impaired.
[0214] On the occasion of adding balloons, it is also possible to
add, in combination, such an anti-slip agent as the one disclosed
in Japanese Kokai Publication 2000-154368 or such an amine compound
capable of rendering the resulting cured product surface uneven and
matted as the one disclosed in Japanese Kokai Publication
2001-164237. Preferred as the amine compound mentioned above are
primary and/or secondary amines having a melting point of
35.degree. C. or higher.
[0215] Also usable as the balloons are thermally expandable minute
hollow particles disclosed in Japanese Kokai Publication 2004-51701
or 2004-66749, for instance. The "thermally expandable minute
hollow particles" are spherical plastic bodies made of a polymer
shell material (vinylidene chloride type copolymer, acrylonitrile
type copolymer or vinylidene chloride-acrylonitrile copolymer) with
a low-boiling compound such as a hydrocarbon containing 1 to 5
carbon atoms as spherically enclosed therein.
[0216] By adding thermally expandable minute hollow particles to
the curable composition of the present invention, it becomes
possible to obtain, without using any organic solvent at all, a
thermally removable adhesive composition which, when no more
required, can be peeled off with ease only by heating without
destruction of the adherend materials. This is based on the
mechanism such that when the adhesive portion is heated, the gas
pressure inside the shells of the thermally expandable minute
hollow particles increases and the polymer shell material is
softened and dramatically expanded to cause peeling at the adhesive
interface.
[0217] When the curable composition of the present invention
contains sealant curing particles as well, the cured products
obtained can have an uneven rough surface and, thus, the decorative
feature thereof can be improved. The preferred diameter, addition
level, material and the like of the sealant curing particles are
disclosed in Japanese Kokai Publication 2001-115142, and the
diameter is preferably 0.1 mm to 1 mm, more preferably 0.2 to 0.5
mm. The addition level is preferably 5 to 100 parts by weight, more
preferably 20 to 50 parts by weight, per 100 parts by weight of the
curable composition. The material is not particularly restricted
but may be any of the materials used in sealing compositions; thus,
mention may be made of urethane resins, silicones, modified
silicones and polysulfide rubbers, for example.
[0218] Among those mentioned above, modified silicone type sealant
curing particles are preferred.
[0219] To the curable composition of the present invention, there
may be added a silicate, if necessary. The silicate acts as a
crosslinking agent on the organic polymer (A) and functions to
bring about improvements in the restorability, durability and creep
resistance of the cured products obtained.
[0220] Further, the addition of a silicate brings about
improvements in the adhesiveness and water-resistant adhesiveness
and in the bond durability under high-temperature and high-pressure
conditions. The silicate is not particularly restricted but
includes, for example, tetraalkoxysilanes or partial hydrolysis
condensation products derived therefrom; more specifically, there
may be mentioned tetraalkoxysilanes (tetraalkyl silicates) such as
tetramethoxysilane, tetraethoxysilane, ethoxytrimethoxysilane,
dimethoxydiethoxysilane, methoxytriethoxysilane,
tetra-n-propoxysilane, tetra-1-propoxysilane, tetra-n-butoxysilane,
tetra-1-butoxysilane and tetra-t-butoxysilane as well as partial
hydrolysis condensation products derived therefrom.
[0221] When a silicate is added, the addition level thereof is
preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10
parts by weight, per 100 parts by weight of the organic polymer
(A).
[0222] The tetraalkoxysilane-derived partial hydrolysis
condensation product mentioned above is not particularly restricted
but includes, for example, products derived from tetraalkoxysilanes
by addition of water thereto to cause partial hydrolysis and
condensation.
[0223] The addition of a tetraalkoxysilane-derived partial
hydrolysis condensation product is preferred since such
condensation product produces significant improvements in
restorability, durability and creep resistance of the cured
products obtained as compared with the corresponding composition
containing the tetraalkoxysilane added thereto.
[0224] Commercially available as the tetraalkoxysilane-derived
partial hydrolysis condensation product are, for example, Methyl
Silicate 51 and Ethyl Silicate 40 (both being products of Colcoat
Co., Ltd.); these can be used as additives.
[0225] For the purpose of inhibiting the surface curability of the
curable composition from changing during storage, it is preferred
that the silicate be selected from among those in which the silicon
atom-bound hydrolyzable groups are the same as the hydrolyzable
groups in the reactive silyl group occurring in the organic polymer
(A). Thus, when the organic polymer (A) contains methoxysilyl
groups, a methoxysilyl group-containing silicate is preferably
selected and, when the organic polymer (A) contains ethoxysilyl
groups, an ethoxysilyl group-containing silicate is preferably
selected.
[0226] In the curable composition of the invention, there may be
incorporated a tackifier, if necessary.
[0227] The tackifier is not particularly restricted provided that
it is one in common use, irrespective of whether it occurs as a
solid or liquid at ordinary temperature. For example, there may be
mentioned styrene block copolymers, hydrogenation products derived
therefrom, phenol resins, modified phenol resins (e.g. cashew
oil-modified phenol resins, tall oil-modified phenol resins),
terpene-phenol type resins, xylene-phenol type resins,
cyclopentadiene-phenol type resins, coumarone-indene type resins,
rosin type resins, rosin ester type resins, hydrogenated rosin
ester type resins, xylene type resins, low-molecular-weight
polystyrene type resins, styrene copolymer resins, petroleum resins
(e.g. C5 hydrocarbon type resins, C9 hydrocarbon type resins, C5C9
hydrocarbon copolymer resins), hydrogenated petroleum resins,
terpene type resins, DCPD resins, and petroleum resins. These may
be added singly or a plurality thereof may be added in
combination.
[0228] The styrene block copolymers and hydrogenation products
derived therefrom mentioned above are not particularly restricted
but include, for example, styrene-butadiene-styrene block
copolymers (SBSs), styrene-isoprene-styrene block copolymers
(SISs), styrene-ethylenebutylene-styrene block copolymers (SEBSs),
styrene-ethylenepropylene-styrene block copolymers (SEPSs) and
styrene-isobutylene-styrene block copolymers (SIBSs).
[0229] When a tackifier is added, the addition level thereof is
preferably 5 to 1,000 parts by weight, more preferably 10 to 100
parts by weight, per 100 parts by weight of the organic polymer
(A).
[0230] In the curable composition of the present invention, there
may be incorporated a solvent or diluent, if necessary. The solvent
or diluent is not particularly restricted but includes, for
example, aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic
hydrocarbons, halogenated hydrocarbons, alcohols, esters, ketones
and ethers. These may be added singly or a plurality thereof may be
added in combination.
[0231] When a solvent or diluent is added, the solvent or diluent
preferably has a boiling point of 150.degree. C. or higher, more
preferably 200.degree. C. or higher, so that the volatile
components in the solvent or diluent may be inhibited from
dissipating into the air on the occasion of indoor use of the
curable composition.
[0232] In the curable composition of the present invention, there
may be incorporated a physical property modifier, if necessary. The
physical property modifier functions so as to adjust the tensile
characteristics and hardness of the resulting cured products.
[0233] The physical property modifier is not particularly
restricted but includes, for example, alkylalkoxysilanes such as
methyltrimethoxysilane, dimethyldimethoxysilane,
trimethylmethoxysilane and n-propyltrimethoxysilane;
alkylisopropenoxysilanes such as dimethyldiisopropenoxysilane,
methyltriisopropenoxysilane and
.gamma.-glycidoxypropylmethyldiisopropenoxysilane; functional
group-containing alkoxysilanes such as
.gamma.-glycidoxypropylmethyldimethoxysilane,
.gamma.-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane,
vinyldimethylmethoxysilane, .gamma.-aminopropyltrimethoxysilane,
N-(.beta.-aminoethyl)aminopropylmethyldimethoxysilane,
.gamma.-mercaptopropyltrimethoxysilane and
.gamma.-mercaptopropylmethyldimethoxysilane; silicone varnishes;
and polysiloxanes. These may be added singly or a plurality thereof
may be added in admixture.
[0234] Among such physical property modifiers, those which form,
upon hydrolysis, a compound containing a monovalent silanol group
in the molecule are preferred since they are effective in reducing
the modulus of the resulting cured products without worsening the
surface stickiness thereof; among them, those which form, upon
hydrolysis, trimethylsilanol are more preferred.
[0235] The compounds which form, upon hydrolysis, a compound
containing monovalent silanol group in the molecular are not
particularly restricted but include: those compounds disclosed in
Japanese Kokai Publication H05-117521; compounds derived from an
alkyl alcohol, such as hexanol, octanol and decanol, and capable of
forming, upon hydrolysis, such an organosilicon compound
represented by R.sub.3SiOH as trimethylsilanol; and those compounds
disclosed in Japanese Kokai Publication H11-241029 which are
compounds derived from a polyhydric alcohol containing 3 or more
hydroxyl groups in each molecule, for example trimethylolpropane,
glycerol, pentaerythritol or sorbitol, and capable of forming, upon
hydrolysis, such an organosilicon compound represented by
R.sub.3SiOH as trimethylsilanol.
[0236] Further, mention may be made of those compounds disclosed in
Japanese Kokai Publication H07-258534 which are derived from an
oxypropylene polymer and capable of forming, upon hydrolysis, such
an organosilicon compound represented by R.sub.3SiOH as
trimethylsilanol and, further, those compounds disclosed in
Japanese Kokai Publication H06-279693 which contain a crosslinkable
hydrolyzable silyl group and a silyl group capable of forming, upon
hydrolysis, a monovalent silanol group-containing compound.
[0237] When a physical property modifier is added, the addition
level thereof is preferably 0.1 to 20 parts by weight, more
preferably 0.5 to 10 parts by weight, per 100 parts by weight of
the organic polymer (A).
[0238] In the curable composition of the present invention, there
may be incorporated a thixotropic agent (anti-sagging agent), if
necessary. The term "thixotropic agent" refers to an agent
functioning to prevent the curable composition from sagging and
improve the workability thereof.
[0239] The thixotropic agent is not particularly restricted but
includes, for example, polyamide waxes; hydrogenated castor oil
derivatives; and metal soaps such as calcium stearate, aluminum
stearate and barium stearate. Further, mention may be made of those
rubber powders having a particle diameter of 10 to 500 .mu.m which
are disclosed in Japanese Kokai Publication H11-349916, and those
organic fibers disclosed in Japanese Kokai Publication 2003-155389.
These thixotropic agents (antisagging agents) may be added singly
or a plurality of species may be added in combination.
[0240] When a thixotropic agent is added, the addition level
thereof is preferably 0.1 to 20 parts by weight per 100 parts by
weight of the organic polymer (A).
[0241] In the curable composition of the present invention, there
may be incorporated, for example, a compound containing an epoxy
group in each molecular, if necessary. By adding an epoxy
group-containing compound, it becomes possible to enhance the
restorability of the cured products obtained.
[0242] The epoxy group-containing compound is not particularly
restricted but includes, for example, epoxidized unsaturated fats
and oils; epoxidized unsaturated fatty acid esters; alicyclic epoxy
compounds; epichlorohydrin derivatives and like compounds; and
mixtures thereof. More specifically, there may be mentioned
epoxidized soybean oil, epoxidized linseed oil,
bis(2-ethylhexyl)-4,5-epoxycyclohexane-1,2-dicarboxylate (E-PS),
epoxyoctyl stearate, epoxybutyl stearate and the like. Among these,
E-PS is preferred.
[0243] When an epoxy compound is added, the addition level thereof
is preferably 0.5 to 50 parts by weight per 100 parts by weight of
the organic polymer (A).
[0244] In the curable composition of the present invention, there
may be added a photocurable substance, if necessary. The
photocurable substance is a substance capable of undergoing, under
the action of light, chemical changes in molecular structure in a
short period of time which lead to changes in physical properties
such as curing. The addition of a photocurable substance to the
curable composition results in the formation of a photocurable
substance-based layer on the surface of the cured products obtained
and thus in improvements in the stickiness and weather resistance
of the cured products.
[0245] The photocurable substance is not particularly restricted
but includes those known in the art, such as organic monomers,
oligomers, resins, and compositions containing any of them; for
example, there may be mentioned unsaturated acrylic compounds,
vinyl cinnamate polymers and azidized resins.
[0246] As the unsaturated acrylic compounds, there may be mentioned
monomers, oligomers, or mixtures thereof, containing one or a
plurality of acrylic or methacrylic unsaturated groups in each
molecule, and, specifically, propylene (or butylene or ethylene)
glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate and like
monomers or oligoesters having a molecular weight not exceeding
10,000. More specifically, there may be mentioned, for example,
such special acrylates as (bifunctional) Aronix M-210, Aronix
M-215, Aronix M-220, Aronix M-233, Aronix M-240 and Aronix M-245;
(trifunctional) Aronix M-305, Aronix M-309, Aronix M-310, Aronix
M-315, Aronix M-320 and Aronix M-325, and (polyfunctional) Aronix
M-400 (all Aronix products being available from Toagosei Co.,
Ltd.). Among these, acrylic functional group-containing compounds
are preferred, and compounds containing, on an average, 3 or more
acrylic functional groups in each molecule are more preferred.
[0247] The vinyl cinnamate polymers are photosensitive resins
having cinnamoyl groups as photosensitive groups, which are
compounds resulting from esterification of polyvinyl alcohol with
cinnamic acid, and many other derivatives of vinyl cinnamate
polymers.
[0248] The azidized resins are known as photosensitive resins in
which azide groups are photosensitive groups and include rubber
photosensitive solutions generally containing a diazide compound
added as a photosensitizer and, further, those detailed examples
are described in "Kankosei Jushi (Photosensitive Resins)"
(published Mar. 1, 1972 by Insatsu Gakkai Shuppanbu Ltd., p. 93
ff., p. 106 ff., and p. 117 ff.). These may be used either singly
or in admixture, if necessary together with a sensitizer.
[0249] In some cases, the addition of a sensitizer such as a ketone
and nitro compound or a promoter such as an amine enhances the
effect.
[0250] When a photocurable substance is added, the addition level
thereof is preferably 0.1 to 20 parts by weight, more preferably
0.5 to 10 parts by weight, per 100 parts by weight of the organic
polymer (A). At levels of 0.1 part by weight or below, the effect
of enhancing the weather resistance of the cured products obtained
is very little and, at levels of 20 parts by weight or above, the
cured products obtained are too hard, tending to undergo cracking
or the like.
[0251] In the curable composition of the present invention, there
may be incorporated an oxygen-curable substance, if necessary. The
oxygen-curable substance can be cured upon reaction with oxygen in
the air, and the addition of an oxygen-curable substance makes it
possible to reduce the stickiness of the cured product surface and
to prevent dirt and dust from adhering to the surface through the
formation of a cured layer in the vicinity of the cured product
surface obtained.
[0252] The oxygen-curable substance is not particularly restricted
but may be any of the compounds containing an unsaturated compound
capable of reacting with oxygen in the air; thus, for example,
there may be mentioned drying oils such as tung oil and linseed
oil, and various alkyd resins obtained by modifying such compounds;
drying oil-modified acrylic polymers, epoxy type resins and
silicone type resins; liquid polymers obtained by polymerizing or
copolymerizing such a diene compound(s) as butadiene, chloroprene,
isoprene and 1,3-pentadiene, for example 1,2-polybutadiene,
1,4-polybutadiene and C.sub.5-C.sub.8 diene polymers; liquid
copolymers obtained by copolymerizing such a diene compound with a
vinyl compound, such as acrylonitrile and styrene, copolymerizable
with the diene compound, in a manner such that the diene compound
serve as the main component, for example NBR and SBR; and, further,
various modifications thereof (maleinated modifications, boiled oil
modifications, etc.).
[0253] Among those mentioned above, tung oil and liquid diene type
polymers are preferred. The oxygen-curable substance to be added
may comprise a single species or a combination of a plurality of
species.
[0254] When a catalyst and/or metal dryer which are capable of
promoting the curing reaction are added in admixture with the
oxygen-curable substance, the effect may be enhanced.
[0255] The catalyst and metal dryer for promoting the curing
reaction are not particularly restricted but include, for example,
metal salts such as cobalt naphthenate, lead naphthenate, zirconium
naphthenate, cobalt octylate and zirconium octylate, and amine
compounds.
[0256] When an oxygen-curable substance is added, the addition
level thereof is preferably 0.1 to 20 parts by weight, more
preferably 0.5 to 10 parts by weight, per 100 parts by weight of
the organic polymer (A). At addition levels below 0.1 part by
weight, the effect of improving the stain resistance of the cured
products obtained tends to become insufficient and, at levels
exceeding 20 parts by weight, the tensile characteristics and the
like of the cured products obtained tend to become impaired.
[0257] Further, the oxygen-curable substance is preferably added in
admixture with a photocurable substance, as disclosed in Japanese
Kokai Publication H03-160053.
[0258] In the curable composition of the present invention, there
may be incorporated an antioxidant, if necessary. By adding an
antioxidant, it becomes possible to enhance the thermal stability
of the cured products obtained.
[0259] The antioxidant is not particularly restricted but includes
hindered phenol type, monophenol type, bisphenol type and
polyphenol type antioxidants. Among these, hindered phenol type
antioxidants are preferred. Also preferred are hindered amine type
light stabilizers such as Tinuvin 622LD and Tinuvin 144; Chimassorb
944 LD and Chimassorb 119FL (all four being products of Chiba
Specialty Chemicals); ADK STAB LA-57, ADK STAB LA-62, ADK STAB
LA-67, ADK STAB LA-63 and ADK STAB LA-68 (all five being products
of Adeka Corporation); and Sanol LS-770, Sanol LS-765, Sanol
LS-292, Sanol LS-2626, Sanol LS-1114 and Sanol LS-744 (all six
being product of Sankyo Lifetech Co., Ltd.). Specific examples of
the antioxidants are disclosed also in Japanese Kokai Publications
H04-283259 and H09-194731.
[0260] When an antioxidant is added, the addition level thereof is
preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5
parts by weight, per 100 parts by weight of the organic polymer
(A).
[0261] In the curable composition of the present invention, there
may be incorporated a light stabilizer, if necessary. By adding a
light stabilizer, the cured products obtained can be prevented from
undergoing photooxidative degradation.
[0262] The light stabilizer is not particularly restricted but
includes benzotriazole type, hindered amine type and benzoate type
compounds. Among these, hindered amine type light stabilizers are
preferred.
[0263] When a light stabilizer is added, the addition level thereof
is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5
parts by weight, per 100 parts by weight of the organic polymer
(A). A specific example of the light stabilizer is disclosed in
Japanese Kokai Publication H09-194731 as well.
[0264] When such a photocurable substance as an unsaturated acrylic
compound is added to the curable composition of the present
invention, a tertiary amine group-containing hindered amine type
light stabilizer is preferably added as disclosed in Japanese Kokai
Publication H05-70531 since, then, the storage stability of the
curable composition is improved.
[0265] The tertiary amine group-containing hindered amine type
light stabilizer is not particularly restricted but includes
Tinuvin 622LD, Tinuvin 144 and Chimassorb 119FL (all three being
products of Ciba Specialty Chemicals Inc.); ADK STAB LA-57, LA-62,
LA-67 and LA-63 (all four being products of Adeka Corporation); and
Sanol LS-765, LS-292, LS-2626, LS-1114 and LS-744 (all five being
products of Sankyo Lifetech Co., Ltd.)
[0266] To the curable composition of the present invention may be
added an ultraviolet absorber, if necessary. When an ultraviolet
absorber is added to the curable composition, the surface weather
resistance of the cured products obtained is improved.
[0267] The ultraviolet absorber is not particularly restricted but
includes benzophenone type, benzotriazole type, salicylate type,
substituted tolyl type and metal chelate type compounds.
[0268] Among these, benzotriazole type ultraviolet absorbers are
preferred.
[0269] When an ultraviolet absorber is added to the curable
composition, the addition level thereof is preferably 0.1 to 10
parts by weight, more preferably 0.2 to 5 parts by weight, per 100
parts by weight of the organic polymer (A).
[0270] The antioxidant, light stabilizer and ultraviolet absorber
mentioned above are preferably added in combination to the curable
composition and, for example, a phenol or hindered phenol
antioxidant, a hindered amine type light stabilizer and a
benzotriazole type ultraviolet absorber are preferably added in
admixture with the curable composition.
[0271] To the curable composition of the present invention may be
added a flame retardant, if necessary. The flame retardant is not
particularly restricted; thus, for example, phosphorus type flame
retardants such as ammonium polyphosphate and tricresyl phosphate;
aluminum hydroxide, magnesium hydroxide, and flame retardants such
as thermally expandable graphite may be added to the curable
composition. The flame retardant to be added thereto may comprise a
single species or a combination of a plurality of species.
[0272] When a flame retardant is added to the curable composition,
the addition level thereof is preferably 5 to 200 parts by weight,
more preferably 10 to 100 parts by weight, per 100 parts by weight
of the organic polymer.
[0273] To the curable composition of the present invention may be
added, if necessary, various additives other than those mentioned
above for the purpose of adjusting various physical properties of
the curable composition or of the cured products to be obtained. As
such additives, there may be mentioned, for example, curability
modifiers, radical inhibitors, metal deactivators, antiozonants,
phosphorus type peroxide decomposers, lubricants, pigments, blowing
agents, antitermites and antifungal agents. Specific examples of
these are disclosed in publications such as Japanese Kokoku
Publications H04-69659 and H07-108928, and Japanese Kokai
Publications S63-254149, S64-22904 and 2001-72854. These additives
may be added singly to the curable composition or a plurality
thereof may be added in combination to the curable composition.
[0274] In cases where the curable composition is of the one-pack
type, the composition contains all components as mixed up in
advance and, thus, curing may proceed during storage if moisture is
present in formulation components. Therefore, those formulation
components which contain moisture are preferably dehydrated and
dried prior to addition or dehydrated during compounding and
kneading by reducing the pressure, for instance.
[0275] When the curable composition is of the two-pack type, it is
not necessary to incorporate the curing catalyst in the main
component having a reactive silyl group-containing organic polymer
and, therefore, even if some moisture is contained in the
formulation components, the risk of the progress of curing
(gelation) is low; in cases where long-term storage stability is
required, however, it is preferred that the formulation components
be dehydrated or dried.
[0276] As for the method of dehydrating or drying, the method
comprising drying by heating or the method comprising dehydrating
under reduced pressure are preferred in cases where the formulation
components are solids such as powders and, in cases where they are
liquids, the vacuum dehydration method and the dehydration method
using a synthetic zeolite, activated alumina, silica gel, quick
lime, magnesium oxide or the like are preferred and, further, the
dehydration method comprising adding an alkoxysilane compound such
as n-propyltrimethoxysilane, vinyltrimethoxysilane,
vinylmethyldimethoxysilane, methyl silicate, ethyl silicate,
.gamma.-mercpatopropylmethyldimethoxysilane,
.gamma.-mercaptopropylmethyldiethoxysilane and
.gamma.-glycidoxypropyltrimethoxysilane; an oxazolidine compound
such as 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine; and an
isocyanate compound to the curable composition and allowing the
same to react with water contained in the formulation components is
also preferred. In this way, the storage stability of the curable
composition is improved by the addition of such an alkoxysilane
compound, oxazolidine compound and isocyanate compound.
[0277] In using vinyltrimethoxysilane or a like alkoxysilane
compound capable of reacting with water for the purpose of drying,
the addition level thereof is preferably 0.1 to 20 parts by weight,
more preferably 0.5 to 10 parts by weight, per 100 parts by weight
of the organic polymer (A).
[0278] The method of preparing the curable composition of the
present invention is not particularly restricted but there may be
employed, for example, such a method known in the art as a method
comprising combining the formulation components mentioned above and
kneading the resulting mixture at ordinary temperature or with
heating using a mixer, roller, kneader, or the like, or a method
comprising dissolving the formulation components using small
portions of an appropriate solvent and then mixing up the
solutions.
[0279] When exposed to the air, the curable composition of the
present invention forms a three-dimensional network structure under
the action of atmospheric moisture and thus is cured to give a
solid having rubber elasticity.
[0280] The curable composition of the present invention can be
suitably used in such fields of application as pressure-sensitive
adhesives; sealants for buildings, ships, automobiles, roads, etc.;
adhesives; impression materials; vibration-proof materials; damping
materials; soundproof materials; expanded/foamed materials; coating
compositions; spray coatings, etc. Among such fields of
application, the use as sealants or adhesives is more preferred
since the cured products obtained are excellent in flexibility and
adhesiveness.
[0281] The curable composition of the present invention can also be
used in such fields of application as back cover sealants for a
solar cell and like electric and electronic part materials;
insulating cover materials for electric wires and cables and other
electric insulating materials; elastic adhesives; contact
adhesives; spray sealants; crack repair materials; tiling
adhesives; powder coating compositions; casting materials; rubber
materials for medical use; pressure-sensitive adhesives for medical
use; sealants for medical devices; food packaging materials; joint
sealants for siding boards and other exterior materials; coating
materials; primers; electromagnetic wave shielding conductive
materials, thermally conductive materials; hot melt materials;
potting agents for electrics and electronics; films; gaskets;
various molding materials; rustproof and waterproof sealants for
wired glass and laminated-glass edges (cut end faces); liquid
sealants for use in automotive parts, electrical machinery parts,
various machinery parts, etc.
[0282] Further, the curable composition can also be used as various
types of hermetically sealants and adhesives since it, either alone
or with the aid of a primer, can adhere to a wide range of
substrates such as glass, ceramics, wood, metals and resin
moldings.
[0283] The curable composition of the present invention can also be
used in the form of interior panel adhesives, exterior panel
adhesives, tiling adhesives, stone pitching adhesives, ceiling
finishing adhesives, floor finishing adhesives, wall finishing
adhesives, vehicle panel adhesives, electric, electronic and
precision apparatus assembling adhesives, direct glazing sealants,
double glazing sealants, sealants for SSG systems, or building
working joint sealants.
BEST MODE FOR CARRYING OUT THE INVENTION
[0284] The following examples and comparative examples illustrate
the present invention more specifically. These are, however, by no
means limitative of the scope of the present invention.
Synthesis Example 1
[0285] Propylene oxide was polymerized using polyoxypropylene diol
with a molecular weight of about 2,000 as an initiator and a zinc
hexacyanocobaltate glyme complex catalyst to give polypropylene
oxide having a number average molecular weight of about 25,500
(polystyrene-equivalent molecular weight measured by using a TOSOH
model HLC-8120 GPC solvent delivery system, a TOSOH model TSK-GEL H
type column, with THF as a solvent). Thereto was then added a
methanol solution of NaOMe in an amount of 1.2 equivalents relative
to the hydroxyl groups of that hydroxyl-terminated polypropylene
oxide, the methanol was distilled off and, further, allyl chloride
was added to the residue for conversion of each terminal hydroxyl
group to an allyl group. The unreacted allyl chloride was removed
by volatilization under reduced pressure. To 100 parts by weight of
the crude allyl-terminated polypropylene oxide obtained were added
300 parts by weight of n-hexane and 300 parts by weight of water
and, after mixing with stirring, the water was removed by
centrifugation. The hexane solution obtained was further mixed with
300 parts by weight of water with stirring, and after the water was
removed again by centrifugation, the hexane was removed by
volatilization under reduced pressure. In the above manner,
allyl-terminated bifunctional polypropylene oxide with a number
average molecular weight of about 25,500 was obtained (this product
is hereinafter referred to as a "polymer P").
[0286] The polymer (P) (100 parts by weight) was reacted with 0.80
part by weight of methyldimethoxysilane at 90.degree. C. for 5
hours in the presence of 150 ppm of an isopropanol solution of a
platinum-vinylsiloxane complex (platinum content: 3% by weight) as
a catalyst to give a methyldimethoxysilyl group-terminated
polyoxypropylene type polymer (A).
[0287] As a result of .sup.1H-NMR measurement (made in CDCl.sub.3
solvent using a Nippon Denshi (JEOL Ltd.) model JNM-LA400), the
average number of terminal methyldimethoxysilyl groups per molecule
was found to be about 1.3.
Synthesis Example 2
[0288] The polymer (P) (100 parts by weight) obtained in Synthesis
Example 1 was reacted with 0.95 part by weight of trimethoxysilane
at 90.degree. C. for 5 hours in the presence of 150 ppm of an
isopropanol solution of a platinum-vinylsiloxane complex (platinum
content: 3% by weight) as a catalyst to give a trimethoxysilyl
group-terminated polyoxypropylene type polymer (T). As a result of
.sup.1H-NMR measurement, the number of terminal trimethoxysilyl
groups was found to be about 1.3 per molecule on an average.
Example 1
[0289] Surface-treated colloidal calcium carbonate (120 parts by
weight; product of Shiraishi Kogyo Kaisha Ltd., trade name:
Hakuenka CCR), 20 parts by weight of titanium oxide (product of
Ishihara Sangyo Kaisha Ltd., trade name: Tipaque R-820), 55 parts
by weight of a plasticizer (product of Kyowa Hakko Kogyo Co., Ltd.,
trade name: DIDP), 2 parts by weight of a thixotropic agent
(product of Kusumoto Chemicals Ltd., trade name: Disparlon #6500),
1 part by weight of an ultraviolet absorber (product of Ciba
Specialty Chemicals Inc., trade name: Tinuvin 327) and 1 part by
weight of a light stabilizer (product of Sankyo Co., Ltd., trade
name: Sanol LS770) were weighed and admixed with 100 parts by
weight of the methyldimethoxysilyl group-terminated
polyoxypropylene type polymer (A) obtained in Synthesis Example 1
and, after thorough kneading, the mixture was passed through a
three-roll paint mill for dispersion.
[0290] Thereafter, the mixture was dehydrated at 120.degree. C. for
2 hours under reduced pressure and, after cooling to a temperature
not higher than 50.degree. C., 5 parts by weight of
.gamma.-(2-aminoethyl)aminopropyltrimethoxysilane (product of Dow
Corning Toray Co., Ltd., trade name: A-1120) as the (D) component
adhesiveness-imparting agent, 3 parts by weight of
.gamma.-glycidoxypropyltrimethoxysilane (product of Dow Corning
Toray Co., Ltd., trade name: A-187), 10 parts by weight of
1-(o-tolyl)biguanide (product of Tokyo Chemical Industry Co., Ltd.,
abbreviated as OTBG) as the (B-1) component silanol condensation
catalyst and 9 parts by weight of neodecanoic acid (product of
Japan Epoxy Resins Co., Ltd., trade name: Versatic 10) as the (C)
component carboxylic acid were added and kneaded. After kneading
under substantially water-free conditions, the resulting mixture
was hermetically packed in a moisture-proof container. A one-pack
type curable composition was thus obtained.
[0291] Since the (B-1) component OTBG has a molecular weight of
191.2 and the (D) component Versatic 10 has a molecular weight of
172.3, the ratio between the number of moles (b) of all nitrogen
atoms in the (B-1) component and the number of moles (c) of all
carboxyl groups in the (C) component, namely the ratio (b)/(c), was
5.
Example 2
[0292] A curable composition was obtained in the same manner as in
Example 1 except that Versatic 10 was used in an amount of 4.5
parts by weight. The ratio between the number of moles (b) of all
nitrogen atoms in the (B-1) component and the number of moles (c)
of all carboxyl groups in the (C) component, namely the ratio
(b)/(c), was 10.
Example 3
[0293] A curable composition was obtained in the same manner as in
Example 1 except that Versatic 10 was used in an amount of 2.3
parts by weight. The ratio between the number of moles (b) of all
nitrogen atoms in the (B-1) component and the number of moles (c)
of all carboxyl groups in the (C) component, namely the ratio
(b)/(c), was 20.
Comparative Example 1
[0294] A curable composition was obtained in the same manner as in
Example 1 except that Versatic 10 used in Example 1 was not
used.
Comparative Example 2
[0295] A curable composition was obtained in the same manner as in
Comparative Example 1 except that the organic polymer (T) was used
in lieu of the organic polymer (A) used in Comparative Example 1
and OTBG was used in an amount of 4 parts by weight.
(Surface Curability)
[0296] Under constant temperature (23.degree. C.) and constant
humidity (50%) conditions, each of the above curable compositions
was spread to a thickness of about 3 mm, and the surface of the
curable composition was touched gently with a microspatula from
time to time and the time required for the composition to become no
more sticking to the microspatula was determined. The results thus
obtained are shown in Table 1.
(Depth Curability)
[0297] Under constant temperature (23.degree. C.) and constant
humidity (50%) conditions, a polyethylene tube with an inside
diameter of 18 mm and a length of 50 mm was filled with each of the
above curable compositions and, after 7 days of curing, the cured
portion was taken out and the length of the cured portion was
measured. The results thus obtained are shown in Table 1.
(Adhesiveness)
[0298] Each of the above curable compositions, in the form of a
rectangle having an approximate size of 3.0 cm in length, 1.5 cm in
width and 1.0 cm in thickness, was brought into close contact with
an adherend substrate (electrolytically colored aluminum, stainless
steel and vinyl chloride resin) and cured under constant
temperature (23.degree. C.) and constant humidity (50%) conditions
for 7 days; then, the adhesiveness was evaluated by 90-degree hand
peel test. The adhesiveness evaluation was made in terms of
fracture mode. In the case of 80 to 100% cohesive failure, the
adhesiveness was evaluated as A; in the case of 40% to below 80%
cohesive failure, as B; and in the case of 0% to below 40% cohesive
failure, as C. The results thus obtained are shown in Table 1.
TABLE-US-00001 TABLE 1 Examples Comparative Examples 1 2 3 1 2
Composi- Organic polymer (A) 100 100 100 100 tion Organic polymer
(T) 100 (parts Filler Hakuenka CCR Shiraishi Kogyo 120 120 120 120
120 by wt.) Titanium oxide Tipaque R-820 Ishihara Sangyo 20 20 20
20 20 Plasticizer DIDP Kyowa Hakko 55 55 55 55 55 Thixotropic
Disparlon #6500 Kusumoto 2 2 2 2 2 agent Chemicals Ultraviolet
Tinuvin 327 Ciba Specialty 1 1 1 1 1 absorber Chemicals Light
stabilizer Sanol LS770 Sankyo 1 1 1 1 1 Adhesiveness- A-1120 Dow
Corning Toray 5 5 5 5 5 imparting agent A-187 Dow Corning Toray 3 3
3 3 3 Amidine compound OTBG Tokyo Chemical 10 10 10 10 4 (B)
Industry Carboxylic acid Versatic 10 Japan Epoxy 9 4.5 2.3 (C)
Resins (b)/(c) 5 10 20 -- -- Results Surface curability (time
required for layer formation) 5.5 hours 5.5 hours 8 hours 15 hours
48 minutes Depth curability 2.5 mm 2.3 mm 2.1 mm 1.9 mm Tensile
100% tensile modulus 0.48 MPa 0.45 MPa 0.47 MPa 0.43 MPa 0.74 MPa
characteristics Breaking strength 1.45 MPa 1.50 MPa 1.62 MPa 1.46
MPa 1.35 MPa Breaking elongation 490% 570% 630% 640% 240%
Adhesiveness (90-degree hand peel) Electrolytically B A A B colored
alminum Stainless steel A A A B Vinyl chloride A A A C resin
[0299] When, as shown in Examples 1 to 3, OTBG was used as the
(B-1) component, Versatic 10 was further added as the (C) component
and, further, the ratio between the number of moles (b) of all
nitrogen atoms in the (B-1) component and the number of moles (c)
of all carboxyl groups in the (C) component, namely the ratio
(b)/(c), was higher than 2, the surface curability, depth
curability and adhesiveness were good. On the other hand, in
Comparative Example 1 in which the addition of the (C) component
was omitted, the surface curability, depth curability and
adhesiveness were all inferior. In Comparative Example 2 in which
the addition of the (C) component was omitted and the
trimethoxysilyl group-terminated polyoxypropylene polymer (T) was
used, the modulus was high and the elongation was inferior.
Examples 4 to 6 and Comparative Examples 3 and 4
[0300] To 100 parts by weight of the methyldimethoxysilyl
group-terminated polyoxypropylene type polymer (A) obtained in
Synthesis Example 1 were added 120 parts by weight of
surface-treated colloidal calcium carbonate (Hakuenka CCR), 20
parts by weight of titanium oxide (Tipaque R-820), 55 parts by
weight of a plasticizer (DIDP), 2 parts by weight of a thixotropic
agent (Disparlon #6500), 1 part by weight of an ultraviolet
absorber (Tinuvin 327) and 1 part by weight of a light stabilizer
(Sanol LS770). After thorough kneading, the mixture was passed
through a three-roll paint mill for dispersion and dehydrated at
120.degree. C. for 2 hours under reduced pressure; thus, a main
composition was prepared. Under constant temperature (23.degree.
C.) and constant humidity (50%) conditions, 2 parts by weight of a
dehydrating agent (A-171), 3 parts by weight of
.gamma.-(2-aminoethyl)aminopropyltrimethoxysilane (product of Dow
Corning Toray Co., Ltd., trade name: A-1120) as the (D) component
adhesiveness-imparting agent, 1-(o-tolyl) biguanide (OTBG) as the
(B-1) component silanol condensation catalyst and neodecanoic acid
(Versatic 10) as the (C) component carboxylic acid were added to
the main composition according to each formulation given in Table
2. Each compound, in the form of a rectangle having an approximate
size of 3.0 cm in length, 1.5 cm in width and 1.0 cm in thickness,
was brought into close contact with an adherend substrate
(electrolytically colored aluminum, stainless steel and vinyl
chloride resin) and cured under constant temperature (23.degree.
C.) and constant humidity (50%) conditions for 7 days; then, the
adhesiveness was evaluated by 90-degree hand peel test. The results
thus obtained are shown in Table 2. The adhesiveness evaluation was
made in terms of fracture mode. In the case of 80 to 100% cohesive
failure, the adhesiveness was evaluated as A; in the case of 40% to
below 80% cohesive failure, as B; and in the case of 0% to below
40% cohesive failure, as C.
[0301] The value of the ratio between the number of moles (b) of
all nitrogen atoms in the (B-1) component and the number of moles
(c) of all carboxyl groups in the (C) component, namely the ratio
(b)/(c), is shown for each compound in Table 2.
TABLE-US-00002 TABLE 2 Examples Comparative Examples 4 5 6 3 4
Composition Main Organic polymer (A) 100 100 100 100 100 (parts by
wt.) composition Filler Hakuenka CCR Shiraishi Kogyo 120 120 120
120 120 Titanium Oxide Tipaque R-820 Ishihara Sangyo 20 20 20 20 20
Plasticizer DIDP Kyowa Hakko 55 55 55 55 55 Thixotropic agent
Disparlon #6500 Kusumoto 2 2 2 2 2 Chemicals Ultraviolet absorber
Tinuvin 327 Ciba Specialty 1 1 1 1 1 Chemicals Light stabilizer
Sanol LS770 Sankyo 1 1 1 1 1 Dehydrating agent A-171 Dow Corning 2
2 2 2 2 Toray Adhesiveness-imparting agent A-1120 Dow Corning 3 3 3
3 3 Toray Amidine compound (B) OTBG Tokyo Chemical 8.3 8.3 8.3 8.3
2.1 Industry Carboxylic acid (C) Versatic 10 Japan Epoxy 7.5 3.7
1.9 22.5 7.5 Resins (b)/(c) 5 10 20 1.7 1.3 Results Adhesiveness
(90-degree hand peel) Electrolytically A A B C C colored alminum
Stainless steel A A A C C Vinyl chloride A A A C C resin
[0302] When, as shown in Examples 4 to 6, OTBG was used as the
(B-1) component, further Versatic 10 was added as the (C) component
and the ratio between the number of moles (b) of all nitrogen atoms
in the (B-1) component and the number of moles (c) of all carboxyl
groups in the (C) component, namely the ratio (b)/(c), was higher
than 2, the adhesiveness was good.
[0303] On the other hand, when the ratio (b)/(c) was not higher
than 2, the adhesiveness was inferior, as shown in Comparative
Example 3 or 4.
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