A disclosed multimode optical fiber comprises a core and a cladding surrounding the core. The core has an outer radius r.sub.1 in between 20 μm and 30 μm. The cladding includes a first outer cladding region having an outer radius r.sub.4a and a second outer cladding region having an outer radius r.sub.4b less than or equal to 45 μm. The second outer cladding region comprises silica-based glass doped with titania. The optical fiber further includes a primary coating with an outer radius r.sub.5 less than or equal to 80 μm, and a thickness (r.sub.5−r.sub.4) less than or equal to 30 μm. The optical fiber further includes a secondary coating with an outer radius r.sub.6 less than or equal to 100 μm. The secondary coating has a thickness (r.sub.6−r.sub.5) less than or equal to 30 μm, and a normalized puncture load greater than 3.6×10.sup.−3 g/micron.sup.2.

A disclosed multimode optical fiber comprises a core and a cladding surrounding the core. The core has an outer radius r.sub.1 in between 20 μm and 30 μm. The cladding includes a first outer cladding region having an outer radius r.sub.4a and a second outer cladding region having an outer radius r.sub.4b less than or equal to 45 μm. The second outer cladding region comprises silica-based glass doped with titania. The optical fiber further includes a primary coating with an outer radius r.sub.5 less than or equal to 80 μm, and a thickness (r.sub.5−r.sub.4) less than or equal to 30 μm. The optical fiber further includes a secondary coating with an outer radius r.sub.6 less than or equal to 100 μm. The secondary coating has a thickness (r.sub.6−r.sub.5) less than or equal to 30 μm, and a normalized puncture load greater than 3.6×10.sup.−3 g/micron.sup.2.

A curable composition containing: a methylene malonate compound, and a Lewis acidic compound. The methylene malonate compound is preferably a compound represented by formula (1) or formula (2). In the formulae (1) and (2), X.sup.1 to X.sup.4 each independently represent O, NR, or C(R).sub.2, R's each independently represent a hydrogen atom, an alkyl group, or an aryl group, R.sup.1 and R.sup.2 each independently represent an alkyl group or an aryl group, and R.sup.3 represents an alkylene group, an arylene group, or a group obtained by combining two or more of these groups.

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The present invention relates to a cuarable resin composition, etc., having an excellent transparency, applicability, and workability. Specifically, the present invention relates to a resin composition, etc., including: (A) a polymer having two or more (meth)acryloyl groups in one molecule thereof; (B) a silica powder surface-treated with an alkyl silane; and (C) boric acid or a borate ester.

The present invention relates to a cuarable resin composition, etc., having an excellent transparency, applicability, and workability. Specifically, the present invention relates to a resin composition, etc., including: (A) a polymer having two or more (meth)acryloyl groups in one molecule thereof; (B) a silica powder surface-treated with an alkyl silane; and (C) boric acid or a borate ester.

A resin composition contains one or more 2-methylene-1,3-dicarbonyl compounds. At least one of the one or more 2-methylene-1,3-dicarbonyl compounds has a molecular weight of 220 to 10,000, and the amount by weight of those of the 2-methylene-1,3-dicarbonyl compounds having a molecular weight of less than 220 relative the entire resin composition of 1 is 0.00 to 0.05. The 2-methylene-1,3-dicarbonyl compounds contain a structural unit represented by formula (I) below. ##STR00001##

A resin composition contains one or more 2-methylene-1,3-dicarbonyl compounds. At least one of the one or more 2-methylene-1,3-dicarbonyl compounds has a molecular weight of 220 to 10,000, and the amount by weight of those of the 2-methylene-1,3-dicarbonyl compounds having a molecular weight of less than 220 relative the entire resin composition of 1 is 0.00 to 0.05. The 2-methylene-1,3-dicarbonyl compounds contain a structural unit represented by formula (I) below. ##STR00001##

The invention relates to a photo-curable liquid resin composition for 3D printing, its preparation process and use, and also to a method of forming a 3D-printed object by using the composition. By using the inventive composition for 3D printing, the improvement of the flexibility and elasticity of the cured composition can be achieved.

The invention relates to a photo-curable liquid resin composition for 3D printing, its preparation process and use, and also to a method of forming a 3D-printed object by using the composition. By using the inventive composition for 3D printing, the improvement of the flexibility and elasticity of the cured composition can be achieved.

A polymerizable composition includes (a) at least one 2-methylene-1,3-dicarbonyl compound and (b) at least one ionic compound including a specific anion.