Coating processes – Direct application of electrical – magnetic – wave – or... – Polymerization of coating utilizing direct application of...
Reexamination Certificate
2002-08-21
2004-05-25
Peng, Kuo-Liang (Department: 1712)
Coating processes
Direct application of electrical, magnetic, wave, or...
Polymerization of coating utilizing direct application of...
C427S387000, C428S156000, C428S429000, C428S447000, C428S450000, C428S426000, C428S448000, C264S299000
Reexamination Certificate
active
06740366
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an article having a predetermined surface configuration and to a production process therefor. More specifically, it relates to an article having a predetermined surface configuration typified by optical elements such as reflection type diffraction gratings, transmission type diffraction gratings, lens arrays and Fresnel lenses and to a production process therefor.
DESCRIPTION OF THE PRIOR ART
Optical elements such as diffraction gratings and microlens arrays must have predetermined fine irregularities in the surface.
As means of forming such irregularities in the surface, there is known a method in which an ultraviolet curable resin monomer is uniformly spread over a substrate and exposed to ultraviolet radiation while it is contacted to a mold having irregularities (JP-A 63-49702) (the term “JP-A” as used herein means an “unexamined published Japanese patent application”).
Also JP-A 62-102445 and JP-A 6-242303 disclose a production process in which irregularities are formed in the surface of a substrate by applying a solution containing silicon alkoxide to a glass substrate, pressing a mold having irregularities against the coating film and heating.
However, in the technology of the above JP-A 63-49702, the ultraviolet curable monomer has large shrinkage in the photopolymerization step and therefore may not achieve high accuracy required for an optical element. The monomer also has a problem with heat resistance.
In contrast to this, an optical element obtained by thermally curing silicon alkoxide has excellent heat resistance but it has large shrinkage in the hydrolysis/polycondensation reaction step and therefore may not achieve high accuracy required for an optical element.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an article having a predetermined surface configuration, such as an optical element having fine irregularities in the surface, which has high heat resistance, small thermal shrinkage at the time of molding a film and high dimensional accuracy, by solving the above problems existent in the prior art.
It is another object of the present invention to provide an industrially advantageous process for producing the above article of the present invention.
Other objects and advantages of the present invention will become apparent from the following description.
According to the present invention, firstly, the above objects and advantages of the present invention are attained by a process for producing an article having a predetermined surface configuration, comprising the steps of:
setting a composition comprising a compound which contains a dimethylsiloxane skeleton having at least three recurring units and at least one polymerizable organic group in the molecule between and in contact with the surface of a substrate and the molding surface of a mold in the form of a film;
applying at least one of heat and ultraviolet radiation to the composition set in the form of a film;
removing the mold and, as required, heating the film; and
forming the article in which the surface of the substrate is covered with a film having a surface configuration which is the inversion of the surface configuration of the mold.
According to the present invention, secondly, the above objects and advantages of the present invention are attained by an article having a predetermined surface configuration, comprising a substrate and an organopolysiloxane film having a predetermined uneven surface and a maximum thickness of 1 &mgr;m to 1 mm formed on the surface of the substrate, wherein the organopolysiloxane film contains 10 to 50 wt % of a methyl group, 1 to 30 wt % of a polymerized segment of a polymerizable organic group and 45 to 89 wt % of a Si—O bonding segment, the total of the methyl group and the polymerized segment of the polymerizable organic group being 11 to 55 wt %.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will be described in detail hereinunder. A description is first given of the production process of the present invention.
The composition used in the process of the present invention comprises a compound having linear and branched dimethylsiloxane skeletons having three or more recurring units. The dimethylsiloxane skeletons contribute to the heat resistance and low shrinkage of the obtained film. When the number of recurring units represented by—((CH
3
)
2
Si—O)— is too small, the viscosity of a liquid composition becomes too low and when the number of the recurring units is too large, the viscosity of the liquid composition becomes too high. In any case, coating and other works and handling become difficult. The number of the recurring units is preferably 3 to 200, more preferably 3 to 100, the most preferably 3 to 50. The compound also has at least one polymerizable organic group in the molecule. Photopolymerization (or thermopolymerization) is caused by the addition polymerization of a radical or cation formed by the optical (or thermal) decomposition of an initiator to the polymerizable organic group. Therefore, shrinkage is smaller than in a dehydration condensation reaction and a chemically bonded uniform organic-inorganic composite film can be formed instantaneously. Consequently, an organic group which is polymerized by light or heat is used as the polymerizable organic group. Examples of the photopolymerizable organic group include acryloxy group, methacryloxy group, vinyl group, epoxy group and organic groups containing these. Examples of the thermopolymerizable organic group include vinyl group, epoxy group and organic groups containing these. At least two of these groups are preferably contained in the molecule of the above compound when the polymerizable organic group is an acryloxy group, methacryloxy group or vinyl group. Organic groups containing an acryloxy group include acryloxy group-substituted alkyl groups such as acryloxypropyl group and acryloxy group-substituted hydroxyalkyl groups. Organic groups containing a methacryloxy group include methacryloxy group-substituted alkyl groups, methacryloxyethoxy group and methacryloxypolyethylene group. Organic groups containing a vinyl group include vinylbenzyloxy group, N-vinylformamide group and vinyloxy group. Organic groups containing an epoxy group include epoxy group-substituted propoxy groups, epoxycyclohexylethyl group and epoxyethylphenyl group. Since heat resistance and humidity resistance lower when too many polymerizable organic groups are contained in the molecule, the number of polymerizable organic groups in the molecule is preferably 50 or less.
The above compound is, for example, a dimethylpolysiloxane having a polymerizable organic group at both terminals represented by the following formula (1):
wherein R
1
and R
2
are each independently a vinyl group or a group having an acryloxy group, methacryloxy group or epoxy group, and n is an integer of 3 to 200, or a dimethylpolysiloxane having a trimethylsilyl group at both terminals and two or more polymerizable organic groups represented by the following formula (2):
wherein R
3
is a vinyl group or a group having an acryloxy group, methacryloxy group or epoxy group, m is an integer of 2 to 200, n is an integer of 1 to 50 when R
3
is an epoxy group and an integer of 2 to 50 when R
3
is another group, with the proviso that m+n is 3 to 200.
Illustrative examples of the compound include (acryloxypropyl)methylsiloxane-dimethylsiloxane copolymer, (methacryloxypropyl)methylsiloxane-dimethylsiloxane copolymer, vinylmethylsiloxane-dimethylsiloxane copolymer and (epoxycyclohexylethyl)methylsiloxane-dimethylsiloxane copolymer.
Out of these compounds, a polydimethylpolysiloxane having a linear acryloxypropyl group at both terminals (the number of recurring units represented by (—((CH
3
)
2
Si—O)— is 3 to 50) and a polydimethylpolysiloxane having a linear methacryloxypropyl group at both terminals (the number of recurring units represented by (—((CH
3
)
2
Si—O)— is 3 to 50) are preferred. Out of these, a polydimethylpolysiloxane having
Hori Masahiro
Kawadu Mitsuhiro
Nakamura Koichiro
Shikata Hiroko
Yamamoto Hiroaki
LandOfFree
Article having predetermined surface shape and method for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Article having predetermined surface shape and method for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Article having predetermined surface shape and method for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3264693