Chemically resistant sealant compositions include high equivalent weight sulfur-containing prepolymers. Upon exposure to chemicals the properties of sealants prepared using the prepolymers exhibit excellent fuel and phosphate ester resistance.

Dual cure compositions include a combination of an organoborane complex and a radical oxidizing agent as co-catalysts. The compositions are curable under dark conditions and can be used to catalyze thiol-ene reactions. The compositions are useful as sealants.

Provided is a sealant sheet formed in a sheet shape. The sealant sheet comprises an epoxy group-containing polysulfide polymer (AB) having two or more epoxy groups per molecule, a thiol compound (C) having two or more thiol groups per molecule, and a photobase generator (D); or a thiol group-containing polysulfide polymer (AC) having two or more thiol groups per molecule, an epoxy compound (B) having two or more epoxy groups per molecule, and a photobase generator (D).

Provided is a sealant sheet formed in a sheet shape. The sealant sheet comprises an epoxy group-containing polysulfide polymer (AB) having two or more epoxy groups per molecule, and a thiol compound (C) having two or more thiol groups per molecule. In the sealant sheet, sulfur atoms in organic components of the sealant sheet has a weight fraction of 32.0% or higher and 36.0% or lower.

Provided is a sealing material for multi-layered glasses, including: a polysulfide resin (A) and a polyester resin (B) which is represented by Formula (1-1): ##STR00001##
or Formula (1-2): ##STR00002##
wherein A represents a dibasic acid residue, G represents a diol residue, X.sub.1 and X.sub.2 represent a hydrogen atom or a group represented by Formula (2-1): ##STR00003## wherein R represents an aromatic group or an aliphatic group, and X.sub.3 and X.sub.4 represent an aromatic group or an aliphatic group, n and m each represent the average number of repetitions of a repeating unit in parentheses and are each a numerical value larger than 0, and some or all A's are aromatic dibasic acid residues, and which has an aromatic dibasic acid residue content of 20 to 70% based on chemical formula weights calculated from the chemical formulae represented by [ ].sub.N and [ ].sub.M and also has a number average molecular weight of 400 to 5,000.

A photocurable sealing material comprising at least a polythiol compound as a first component, wherein, in the case where the photocurable sealing material is used to produce two sheets having a thickness of 1 mm, a width of 25 mm, and a length of 200 mm, the two sheets are photocured by irradiation with an ultraviolet ray, then the photocured sheets are laminated, and the laminate is subjected to a load of 10 kg for 10 seconds, an action of causing the lamination interface between the two sheets to disappear is exhibited, and the self-adhesion strength in a T-type peel test is 5 N/25 mm or more when the sheets are pulled at a peel speed of 300 mm/min.

A sealant material for sealing threaded pipe joints that is a multifilament or spun polyphenylene sulfide yarn and a joint sealing composition comprising a silicone oil or a natural oil with a smoke point of about 230 C. or higher. The polyphenylene sulfide yarn is coated with the joint sealant composition. The material forms an effective seal and is resistant even when used in systems in which it is exposed to temperatures in excess of 280 C. The material may be provided in a dispenser.

A polythioether prepolymer including functional groups capable of being obtained by the reaction: of at least one compound T having a number f of thiol functional group number selected from 2, 3, 4 and 6, with at least one compound E having a number g of epoxy functional groups number selected from 2 and 3. Also, a method of preparation for this prepolymer, a composition including this prepolymer and an oligomer as well as its use as a mastic and a polythioether polymer obtained from this polythioether prepolymer with an oligomer.

Provided are sealant compositions that include a first component and second component. The first component contains a polysulfide, a polythioether, or a copolymer or combination thereof containing pendant or terminal thiol groups, while the second in component contains an ethylenically-unsaturated compound and either the first or second component further contains a photoinitiator. Alternatively, the second component can contain a polyepoxide and either the first or second component can contain a photolatent base and a photosensitizer. The first or second component further contains a colorant that substantially reflects or substantially transmits light over the wavelength range from 350 nm to 500 nm. These compositions can provide cure-on-demand sealant formulations that comply with Class B sealant regulations on color, provide an acceptable depth of cure, and allow two-part mixing to be easily distinguishable.

A low viscosity polysulfide sealant composition. The composition comprises a curable polysulfide polymer; a crosslinking agent; and a plurality of core-shell particles. The core-shell particles comprise: a core comprising a ferromagnetic material; and a shell comprising silica treated with an organic sulfur containing compound. The shell is capable of bonding with the polysulfide polymer.