An acrylic rubber containing: an alkyl acrylate unit; a crosslinking monomer unit; a unit of a bifunctional monomer represented by the following formula (A-1):

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wherein n represents 1 to 9, R.sup.1 represents a hydrogen atom or a methyl group, and R.sup.2 represents an alkanediyl group having 2 to 4 carbon atoms; and an ethylene unit, wherein the acrylic rubber has a toluene insoluble content of 4 to 40% by mass.

The invention relates to an efficient process for the preparation and isolation of rubber particles formed in aqueous media and highly pure rubbers obtained thereby. The invention further relates to copolymer products comprising the same or derived therefrom.

An acrylic rubber contains a copolymer of a monomer mixture of: 25 to 46 wt. % of alkoxyalkyl acrylate, 23 to 37 wt. % of 2-ethylhexyl acrylate, 9 to 17 wt. % of alkyl methacrylate, 1 to 3 wt. % of monoalkyl fumarate and the remaining amount is ethyl acrylate. This acrylic rubber improves hydrolysis resistance by introducing a specific alkyl acrylic monomer with extremely low hydrolysis property i.e. low hydrophilicity, and at the same time satisfies all of oil resistance, cold resistance, and hydrolysis resistance in a well-balanced manner.

An acrylic rubber composition comprising 5 to 15 parts by weight of a plasticizer having a solubility parameter SP value (by Small's method) of 8.5 to 10.5 based on 100 parts by weight of super cold resistant grade acrylic rubber having a glass transition point Tg of −42° C. or less, wherein the acrylic rubber composition can give a vulcanizate with the TR10 value, which is an index of cold resistance, of −42° C. or less both initially and after oil dipping. In the acrylic rubber composition, first, the ratio of an acrylate monomer that constitutes acrylic rubber is adjusted, thereby the low temperature characteristics can be maintained even in an oil contact environment. This intentionally reduces the oil resistance of the vulcanized rubber molded product, thereby increasing the amount of oil swelling into the vulcanized rubber molded product and improving the flexibility in a low temperature environment.

The purpose of the present invention is to obtain an ethylene⋅α-olefin⋅non-conjugated polyene copolymer that has a low permanent compression set at low temperatures, is flexible, and has an excellent balance of rubber elasticity at low temperatures and tensile strength at normal temperatures. This ethylene-based polymer is an ethylene⋅α-olefin⋅non-conjugated polyene copolymer that includes units derived from ethylene (A), units derived from an α-olefin (B) containing 4-20 carbon atoms, and units derived from a non-conjugated polyene (C) and satisfies (1)-(4). (1) The molar ratio of (A) to (B) is 40/60-90/10, (2) the contained amount of the units derived from (C) is 0.1-6.0 mol %, (3) ML.sub.(1+4)125° C. is 5-100, and (4) the B value is 1.20 or more.

A photocurable composition is provided. A cured product formed by curing the photocurable composition has reworkability and excellent heat resistance while having flexibility. The photocurable composition includes a telechelic acrylic polymer having an acryloyl group at both ends; a polyfunctional acrylic polymer having acryloyl groups; a monofunctional acrylic monomer; and a fumed silica including at least one of a hydrophilic fumed silica or a fumed silica having a polar group. The photocurable composition has a Martens hardness of 0.07 to 0.75 N/mm.sup.2, where the Martens hardness is a hardness after the photocurable composition is cured.

A flame-retardant rubber composition is provided which is excellent in flame retardancy and rubber properties and reduces environmental load. The flame-retardant rubber composition comprises an ethylene/α-olefin/non-conjugated diene copolymer, a hydrated metal oxide, a silane coupling agent, a plasticizer, and a cross-linking agent, wherein a carbon number of the α-olefin of the ethylene/α-olefin/non-conjugated diene copolymer is three and more, and 180 to 350 parts by mass of the hydrated metal oxide and 10 to 60 parts by mass of the plasticizer are included per 100 parts by mass of the ethylene/α-olefin/non-conjugated diene copolymer.

Described herein are sealant compositions with low shrinking volume. The sealant compositions include a glass filler. The sealant compositions are useful in a variety of building and construction applications, as well as interior or exterior trim work applications.

A pressurised dispensing container (10) comprising a container (11) for product to be dispensed, and a valve fixed to the container, wherein the container contains a propellant comprising 1,1-difluoroethane or a derivative thereof and optionally ethanol. The valve comprises a valve stem (15), a valve body (16, 18) and one or more seals (20, 21), the valve stem being slidable within the valve body, the one or more seals co-operating with the valve stem for regulating discharge of a fluid. The valve further comprises a sealing gasket (14) for sealing the valve to the dispensing container. The one or more seals (20, 21) is/are formed from (i) an elastomeric composition, preferably an elastomeric composition comprising an ethylene-propylene-diene terpolymer. The sealing gasket (14) is formed from (ii) an elastomeric composition comprising an isobutylene polymer or co-polymer thereof.

A gasket includes an elastic part containing a rubber having a dynamic-to-static ratio, Kd/Kst, of 2.5 or lower, wherein the dynamic-to-static ratio, Kd/Kst, is a ratio between a dynamic spring constant, Kd, and a static spring constant, Kst. The dynamic spring constant, Kd, represents a constant as measured under conditions of 23±2° C., 100 Hz, and a strain amplitude of 0.1% according to JIS K6394:2007, and the static spring constant, Kst, represents a constant as measured under conditions of 23±2° C. and a strain amplitude of 0.1% according to JIS K6394:2007.