A liquid crystalline polyurethane elastomer is produced by reacting an isocyanate component, a high-molecular-weight polyol component and a mesogenic diol represented by formula (1), and having a crosslinking site that is introduced by a tri-functional or higher isocyanate in the isocyanate component and/or a high-molecular-weight polyol having a number average molecular weight of 400 or more and less than 7000 and having three or more hydroxy groups, in the high-molecular-weight polyol component, wherein the melting point of a mesogenic unit does not exist in a temperature range lying between the glass transition temperature (Tg) and the (liquid crystal phase)-to-(isotropic phase) transition temperature (Ti) of the polyurethane elastomer, and a liquid crystal is developed at a temperature between the Tg and the Ti. (In the formula, X represents an alkylene group having 3 to 20 carbon atoms; and Y represents a single bond, —N═N—, —CO—, —CO—O— or —CH═N—). ##STR00001##

A polymerizable composition includes a polymerizable liquid crystal compound of Formula (I) and a urethane (meth)acrylate monomer including a urethane bond and three or more (meth)acryloyl groups:
Q.sup.1-Sp.sup.1A-L.sub.m-1A-Sp.sup.2-Q.sup.2(I)
In Formula (I), A represents a cyclic divalent group (at least one is a divalent saturated hydrocarbon ring group), L preferably represents C(O)O or OC(O), m represents 3 to 12, Sp.sup.1 and Sp.sup.2 preferably are alkylene, and any one of Q.sup.1 and Q.sup.2 represents a polymerizable group. A film including a layer obtained by curing the polymerizable composition; and a film adjacently including a layer obtained by curing the polymerizable composition including a polymerizable liquid crystal compound represented by Formula (I) and a layer obtained by curing a composition including a urethane (meth)acrylate monomer and a manufacturing method thereof, are also disclosed. The polymerizable composition includes a polymerizable liquid crystal compound having low birefringence and provides a highly durable optical film.

A liquid crystal composition including a polymerizable liquid crystal compound capable of expressing birefringence with reverse wavelength distribution and a surfactant containing a fluorine atom, a 1-octanol/water partition coefficient of the surfactant being less than 5.0.

A liquid crystal composition including a polymerizable liquid crystal compound capable of expressing birefringence with reverse wavelength distribution and a surfactant containing a fluorine atom, a 1-octanol/water partition coefficient of the surfactant being less than 5.0.

Provided is a thermoresponsive material containing bubbles and has improved durability. A thermoresponsive material 1 whose state changes, depending on a change in temperature, comprises a matrix 2 in which bubbles 4 having an average diameter of 30 to 400 m are dispersed. Satisfied is D/a0.7, where D represents the standard deviation of diameters of the bubbles 4, and a represents the average diameter of the bubbles 4. Satisfied is 0.3V.sub.1/V.sub.20.9, where V.sub.1 represents the volume of the bubbles 4 at room temperature, and V.sub.2 represents the apparent volume of the matrix 2 at room temperature. The matrix 2 contains a liquid crystalline polyurethane.

The present invention focuses on a change in elastic modulus or rupture stress of a liquid crystalline polymer that occurs when the liquid crystalline polymer undergoes phase transition from a liquid crystalline phase to an isotropic phase. The thermoresponsive material comprises a liquid crystalline polymer that reversibly transitions between a liquid crystalline phase and an isotropic phase, in response to a change in temperature, the liquid crystalline polymer serving as a matrix. Satisfied is E.sub.1/E.sub.21000, where E.sub.1 represents the elastic modulus of the matrix when the matrix includes the liquid crystalline phase, and E.sub.2 represents the elastic modulus of the matrix when the matrix includes the isotropic phase. Satisfied is .sub.1/.sub.240, where .sub.1 represents the rupture stress of the matrix when the matrix includes the liquid crystalline phase, and .sub.2 represents the rupture stress of the matrix when the matrix includes the isotropic phase.

The present invention provides a polymerizable composition including a polymerizable liquid crystal compound of Formula (I) and a urethane (meth)acrylate monomer including a urethane bond and three or more (meth)acryloyl groups;

Q.sup.1-Sp.sup.1A-L.sub.m-1A-Sp.sup.2-Q.sup.2(I)

A represents a cyclic divalent group (at least one thereof is a divalent saturated hydrocarbon ring group), L represents C(O)O, OC(O), and the like, and m represents 3 to 12, Sp.sup.1 and Sp.sup.2 are alkylene and the like, any one of Q.sup.1 and Q.sup.2 represents a polymerizable group; a film including a layer obtained by curing the polymerizable composition; and a film adjacently including a layer obtained by curing polymerizable composition including a polymerizable liquid crystal compound represented by Formula (I) and a layer obtained by curing composition including a urethane (meth)acrylate monomer and a manufacturing method thereof. The polymerizable composition includes a polymerizable liquid crystal compound having low birefringence and can provide a highly-durable optical film.

The purpose of the present invention is to provide: a thermally responsive liquid-crystal polyurethane elastomer which is capable of being industrially continuously molded, and which is liquid crystal and has rubber elasticity at low temperatures (in the vicinity of room temperature); and a production method and a starting material therefor. This liquid-crystal urethane compound is obtained by reacting a mesogenic group-containing compound having at least active hydrogen groups, an alkylene oxide and/or a styrene oxide, and a diisocyanate compound.