Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2001-03-30
2002-09-17
Moore, Margaret G. (Department: 1712)
Stock material or miscellaneous articles
Composite
Of silicon containing
C528S017000, C528S018000, C528S034000, C528S035000, C156S329000, C156S334000, C106S287110, C106S287120, C106S287160
Reexamination Certificate
active
06451439
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a primer composition comprising a saturated hydrocarbon polymer having at least one silicon-containing group which has hydroxyl group or hydrolyzable group bound to the silicon atom and is capable of crosslinking under formation of a siloxane bond (hereinafter referred to as “reactive silicon group”) and to a method of effecting adhesion for sealing compositions using the same.
PRIOR ART
In recent years, elastic sealing compositions have been used widely in buildings, motor vehicles and so on. Sealing compositions are materials used for the purpose of filling up junctions or gaps between various parts and providing airtightness and watertightness. Therefore, they are required to show good adhesive properties for various substrates constituting joints, window frames and the like, namely inorganic materials such as glass, ceramics, metals, cement, mortar, etc., or organic materials such as plastics (hereinafter collectively referred to as “substrates”). However, the adhesive properties of sealing compositions are still unsatisfactory and, therefore, the use of primers is essential in many cases.
On the other hand, silicone-based, modified silicone-based, polysulfide-based and polyurethane-based sealing compositions are well known as compositions to be applied to joints of the interior and exterior of general buildings. These sealing compositions are used properly based on the policy of “the right thing in the right place”. Namely, suitable sealing compositions are selected according to the joints (inclusive of substrate species) to be sealed. Thus, exclusive-use primers adapted to respective sealing compositions have been developed.
As regards primers for sealing compositions for buildings, urethane-based primers containing an isocyanate prepolymer as a main component, and silane type primers constituted of a low-molecular-weight silane compound such as a silane coupling agent, or an organopolysiloxane, among others, are commercially available. However, it is a problem that even when these primers are used, the weather resistance and water resistance of the adhesion are not satisfactory and the effects of the primers cannot be produced over a prolonged period of time.
On the other hand, sealing compositions containing, as the main component thereof, a saturated hydrocarbon polymer containing a reactive silicon group (in particular isobutylene-based sealing compositions with an isobutylene-based polymer as the main chain skeleton) have recently been developed. These isobutylene-based sealing compositions are characterized in that they are excellent in dynamic follow properties, heat resistance, weather resistance, water resistance and coatability and do not contaminate joint surroundings. Their performance characteristics are thus suited for their use as universal sealing compositions. However, no exclusive-use primers for isobutylene-based sealing compositions have ever been developed.
SUMMARY OF THE INVENTION
The present invention has its object to provide a primer composition excellent in adhesion properties to various substrates, in particular a primer composition for effecting good adhesion, to various substrates, of sealing compositions containing, as a Main component, a saturated hydrocarbon polymer having at least one reactive silicon group, as well as a method of effecting adhesion.
The present inventors made intensive investigations in an attempt to solve such problems and, as a result, found that the above object can be accomplished by providing a primer composition containing a saturated hydrocarbon polymer having at least one reactive silicon group. The present invention has now been completed based on such findings.
The present invention thus relates to a primer composition which comprises (A) a saturated hydrocarbon polymer having at least one silicon-containing group which has hydroxyl group or hydrolyzable group bound to the silicon atom and is capable of crosslinking under formation of a siloxane bond, in particular to a primer composition which comprises 0.1 to 10,000 parts by weight of (B) a silane coupling agent per 100 parts by weight of the (A) saturated hydrocarbon polymer having at least one silicon-containing group which has hydroxyl group or hydrolyzable group bound to the silicon atom and is capable of crosslinking under formation of a siloxane bond.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is now described in detail.
The saturated hydrocarbon polymer having at least one reactive silicon group, namely component (A), to be used in the present invention is a component characterizing the present invention. It shows good adhesion to various substrates such as glass and metals and functions as a component forming films excellent in resistance to weather through glass and in water resistance. Thus, it is a component providing the primer composition of the present specification with strong adhesion and durability.
This saturated hydrocarbon polymer having at least one reactive silicon group, namely component (A), is a polymer substantially free of carbon-carbon unsaturated bonds other than aromatic ring bonds. As such, there may be mentioned, for example, polyethylene, polypropylene, polyisobutylene, hydrogenated polybutadiene and hydrogenated polyisoprene.
The reactive silicon group is typically a group represented by the general formula (1)
wherein R
1
and R
2
each independently is a hydrogen atom, an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an aralkyl group containing 7 to 20 carbon atoms or a triorganosiloxy group of the formula (R′)
3
SiO— (in which each R′ independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group containing 1 to 20 carbon atoms), each X independently represents a hydroxyl group or a hydrolyzable group, a is 0, 1, 2 or 3, b is 0, 1 or 2, to the exclusion of the case where a and b are simultaneously 0 (zero), and m is 0 (zero) or an integer of 1 to 19.
As the hydrolyzable group, there may be mentioned, for example, a hydrogen atom and groups commonly used for the same purposes, such as alkoxy, acyloxy, ketoximate, amino, amido, aminoxy, mercapto and alkenyloxy groups.
Among these, alkoxy, amido, aminoxy groups are preferred and alkoxy groups are most preferred because of their mild hydrolyzability and ease of handling.
One to three hydrolyzable or hydroxyl groups can be bound to one silicon atom and the sum (a+&Sgr;b) is preferably within the range of 1 to 5. When two or more hydrolyzable or hydroxyl groups are bound in the reactive silicon group, they may be the same or different.
The number of silicon atoms constituting the reactive silicon group is one or more. When silicon atoms are connected via siloxane bonding, the number thereof is preferably not more than 20.
In particular, reactive silicon groups represented by the general formula (2)
wherein R
2
, X and a are as defined above, are readily available, hence preferred.
The number of reactive silicon groups per molecule of the (A) saturated hydrocarbon polymer is not less than 1, preferably 1.1 to 5. When the number of reactive silicon groups per molecule is below 1, the curability will be insufficient and thereby good coats may not be obtained in some instances.
The reactive silicon group or groups may occur at one or both ends of and/or within the molecular chain of the saturated hydrocarbon polymer. In particular, when the reactive silicon group or groups occur at one or both ends of the molecular chain, the amount of those effective network chains of the saturated hydrocarbon polymer component contained in the finally formed cured coats increases, therefore those are preferred owing to making it easy to obtain high-strength coats.
These saturated hydrocarbon polymers having at least one reactive silicon group, namely component (A), may be used either singly or in combination.
The polymer constituting the (A) saturated hydrocarbon polymer having at least one reactive silicon group to be used in the
Chiba Makoto
Okamoto Toshihiko
Takase Junji
Connolly Bove & Lodge & Hutz LLP
Kaneka Corporation
Moore Margaret G.
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