Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Patent
1993-12-14
1995-07-11
Berman, Susan W.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
522172, 528 25, C09J 402, C09J18307, C09J13308, C09J13310
Patent
active
054322081
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD OF APPLICATION
This invention relates to a photocuring adhesive which hardens and exhibits excellent bonding strength when irradiated by energy such as ultraviolet light or visible light, and more specifically to a photocuring adhesive having excellent water resistance, humidity resistance, low temperature resistance and heat shock resistance when used as an adhesive for glass or ceramics.
BACKGROUND ART
Conventionally, photocuring adhesives consisted of a monomer composition prepared by mixing a low viscosity monomer generally referred to as a reactive diluent, such as trimethylolpropane tri(meth)acrylate or hydroxyethyl (meth)acrylate, with an oligomer such as urethane (meth)acrylate. The latter was obtained by reacting an epoxy(meth)acrylate having (meth)acryloxy groups at both ends of a bis-phenol A skeleton or a compound having no less than two isocyanate groups such as isophorone diisocyanate with 2-hydroxyethyl (meth)acrylate or the like. A small quantity of a photopolymerization initiator was then added.
Compared to the solvent dilution adhesives or thermocuring adhesives which were previously used, these photocuring adhesives are now much more common as they have the following advantages.
Firstly, photocuring adhesives basically do not contain any solvent which has an effect on adhesive properties. Compared to solvent vaporizing adhesives, therefore, they present practically none of the risk associated with handling the adhesive (that occurs when large quantities of solvent evaporate) or adhesion breakdown due to the marked volume contraction. Moreover, photocuring adhesives develop practically useful adhesive properties when irradiated for a few seconds or minutes. Compared to conventional thermocuring adhesives which required heating for a period ranging from several hours to several tens of hours, therefore, they speed up the adhesive process and permit large savings of the energy previously used for heating, while at the same time there is practically no damage to the substrate, such as thermal aging.
Due to these advantages, photocuring adhesives find application in, for example, fixing cover glasses to the display plates of wristwatches, or assembling liquid crystal display panels. Recently, they have begun to be used also for the bonding or assembly of optical devices in optronics such as optical disks, optical communications and optical circuits.
However, conventional photocuring adhesives have a disadvantage in that they generally have poor resistance to water or humidity after adhesion. Also, in very cold environments such as at temperatures of -20.degree. C. or below or when there is a sudden temperature change, these photocuring adhesives easily peel off.
Precision-machined products such as for example wristwatches or liquid crystal display devices bonded with these adhesives had insufficient durability, while in the optronics field the reliability of devices assembled by bonding could not be improved. A solution to these problems was therefore earnestly desired.
Attempts were made to improve low temperature properties by using silicon rubbers which cure at room temperature (RTV rubbers), or photocuring adhesives which comprise silicon oligomers having free radical reactivity.
In the case of RTV rubbers, however, not only is it difficult to achieve curing in a short time period, but pot life is also short. Further, as they offer no more than one-tenth the bonding strength of conventional adhesives, and as there are also problems of workability and reliability, they are not practical.
Photocuring adhesives using silicon oligomers having free radical reactivity can be cured by exposure to light, but like RTV rubbers they give poor bonding strength. Even if there are no problems in usage in the temperature range from several degrees Centigrade below zero to 20.degree. C., the bonded materials easily separate from one another at lower temperatures or in the event of a sudden temperature change. They thus had poor reliability, and did not solve the problems inherent in t
REFERENCES:
patent: 4136250 (1979-01-01), Mueller et al.
patent: 4943613 (1990-07-01), Arai et al.
patent: 5007975 (1991-04-01), Yamamoto et al.
patent: 5104591 (1992-04-01), Masuhara et al.
Komiya Shigeo
Masuhara Eiichi
Satou Yumiko
Sawamoto Takeyuki
Berman Susan W.
Japan Institute of Advanced Dentistry
LandOfFree
Photocuring adhesive containing an oligo siloxanyl di(meth)acryl does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photocuring adhesive containing an oligo siloxanyl di(meth)acryl, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photocuring adhesive containing an oligo siloxanyl di(meth)acryl will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-503850