Abstract: The present invention is intended to provide a photosensitive rubber plate which is superior in transparency and strength balance and high in rate of washing with water after light exposure, and a photosensitive composition used for obtaining the rubber plate. The photosensitive composition contains 20-65 parts by weight of a block copolymer havingat least one polymer block A consisting of a polymer containing 95% by weight or more of an aromatic vinyl monomer unit andat least one polymer block B consisting of a conjugated diene polymer containing 20% by weight or more of a conjugated diene monomer unit and having a vinyl bond content in the conjugated diene monomer unit, of 15-70% by weight.35-80 parts by weight of a hydrophilic copolymer, the total amount of the block copolymer and the hydrophilic copolymer being 100 parts by weight,5-300 parts by weight of a photopolymerizable ethylenically unsaturated monomer, and0.1-10 parts by weight of a photopolymerization initiator.

Abstract: A photosensitive composition which comprises5 to 55 parts by weight of a linear block copolymer 1 consisting essentially of only one polymer block A which is a polymer consisting essentially of aromatic vinyl monomer units as the main constitutive units and conjugated diene monomer units as secondary monomer units, and only one or two polymer blocks B each of which is a polymer consisting essentially of conjugated diene monomer units as the main constitutive units and aromatic vinyl monomer units as secondary monomer units, wherein among all the monomer units the aromatic vinyl monomer units constitute 15 to 30% by weight, the conjugated diene monomer units constitute 85 to 70% by weight, the total amount of the aromatic vinyl monomer units and the conjugated diene monomer units being 100% by weight, and wherein the total amount of the aromatic vinyl monomer units constituting molecular chain portions each having 8 or more successive aromatic vinyl monomer units is 30% by weight or more of the amount of all t

Abstract: A safety device for use in a clamping unit of a molding machine is provided with an improved mechanism to always secure safety when the thickness of a mold is adjusted. The device comprises a safety rod having a predetermined number of engagement stepped portions and tapered surfaces formed alternately at a front end portion at predetermined intervals, a support block for supporting the safety rod, a lever member, a stopper engaged with the engagement stepped portion of the safety rod from sideways, and an operation member having a link bar arranged horizontally in such a manner that the link bar can swing freely and always located below the end portion of the lever member.

Abstract: The present invention is intended to provide a photosensitive rubber plate high in strength balance and image reproducibility and a photosensitive elastomer composition used for obtaining the rubber plate. A photosensitive elastomer composition is obtained by kneading 65 parts by weight of a phosphoric acid ester group-containing random copolymer (monomers composition: 60% of butadiene, 9% of methyl methacrylate, 20% of 2-methacryloxyethyl phosphate, 10% of styrene and 1% of divinylbenzene), 35 parts by weight of a polystyrene-polybutadiene-polystyrene type block copolymer, 15 parts by weight of 1,7-heptanediol dimethacrylate, 1 part by weight of benzoin methyl ether and 0.02 part of methylhydroquinone. By interposing this photosensitive elastomer composition between two polyester films and pressurizing them with a press, a photosensitive rubber plate having a total thickness of 3 mm is obtained.

Abstract: A photosensitive composition comprising:(A) 35-80 weight parts of a phosphorus-containing hydrophilic copolymer made by copolymerization of a mixture of (a) 5-30 weight % of a phosphate ester group-containing unsaturated monomer, (b) 40-90 weight % of a conjugated diene monomer, and (c) 0-50 weight % of other monoolefinically unsaturated monomer;(B) 65-20 weight parts of a thermoplastic elastomer; the sum of (A) plus (B) being 100 weight parts;(C) 5-300 weight parts of a photopolymerizable ethylenically unsaturated monomer; and(D) 0.1-10 weight parts of a photopolymerization initiator.The photosensitive composition is useful for a photosensitive rubber plate and a flexographic printing plate.

Abstract: A machine for pitching baseballs includes two discs which are mounted on independently rotatable shafts. The discs have urethane at their peripheries. The spacing between the shafts can be adjusted in order to set the width of a gap between the discs. A ball feed mechanism inserts balls into the gap between the discs, which then fling the balls outward in a pitching style which depends upon the orientation of the pitching machine and the relative rotational speeds of the discs. In one embodiment, the ball feed mechanism employs a tubular feed body having a tapered outlet end which is positioned adjacent the gap. A piston in the feed body reciprocates to push the balls out. In another embodiment, the ball feed mechanism is mounted on a chassis having casters and is connected via a flexible hose to a feed nozzle positioned adjacent the gap. A reciprocating slider transfers balls from a storage chamber to an inverted-T tube arrangement, whence they are blown pneumatically through the hose to the feed nozzle.

Abstract: A machine for pitching baseballs includes two discs which are mounted on independently rotatable shafts. The discs have urethane at their peripheries. The spacing between the shafts can be adjusted in order to set the width of a gap between the discs. A ball feed mechanism inserts balls into the gap between the discs, which then fling the balls outward in a pitching style which depends upon the orientation of the pitching machine and the relative rotational speeds of the discs. In one embodiment, the ball feed mechanism employs a tubular feed body having a tapered outlet end which is positioned adjacent the gap. A piston in the feed body reciprocates to push the balls out. In another embodiment, the ball feed mechanism is mounted on a chassis having casters and is connected via a flexible hose to a feed nozzle positioned adjacent the gap. A reciprocating slider transfers balls from a storage chamber to an inverted-T tube arrangement, whence they are blown pneumatically through the hose to the feed nozzle.

Abstract: A process for polymerizing 1,3-butadiene, comprising bring into contact a 1,2-polymerization catalyst consisting essentially of a soluble cobalt compound, an organic aluminum halide, an organic lithium compound, and carbon disulfide or phenyl isothiocyanate with 1,3-butadiene in a polymerization medium. The process can be applied particularly advantageously in the preparation of 1,2-polybutadiene, and the resultant 1,2-polybutadiene has a content of syndiotactic 1,2-structural units of not less than 90%, a melting point of 200.degree. C. to 220.degree. C., and an intrinsic viscosity [.eta.] of 1.2 to 7.

Abstract: Polybutadiene consisting of from 5% to 30% by weight of a boiling n-hexane-insoluble fraction and from 70% to 95% by weight of a boiling n-hexane-soluble fraction and having enhanced mechanical strength is prepared by polymerizing 1,3-butadiene in a polymerization solvent in the presence of a specific catalyst consisting essentially of (A) a cobalt compound catalytic component soluble in the polymerization solvent; (B) an organic aluminum halide catalytic component; (C) a trialkyl aluminum-water reaction product in catalytic component, and (D) a catalytic component consisting of carbon disulfide and/or phenyl isothiocyanate, and by isolating the resultant polybutadiene from the reaction mixture.

Abstract: A 1,2-polymerization of 1,3-butadiene is carried out in a polymerization solvent in the presence of a 1,2-polymerization catalyst consisting essentially of a cobalt compound soluble in the polymerization solvent, an organic aluminum halide, an organic magnesium compound, and carbon disulfide and/or phenyl isothiocyanate and in the presence or absence of a cis-1,4-polymerization product of 1,3-butadiene.

Abstract: Poly-.alpha.-olefin, for example, polypropylene, is produced by subjecting a feed containing an .alpha.-olefin having 3 or more carbon atoms, to a preliminary polymerization at 40.degree. C. or less in the presence of a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound of the formula, R.sup.3 MgX wherein R.sup.3 =C.sub.1-8 alkyl and X=halogen, with a reaction product of an aluminium halide with an organic silicon compound of the formula, R.sub.n.sup.1 Si(OR.sup.2).sub.4-n, wherein R.sup.1 =C.sub.1-8 alkyl or phenyl, R.sup.2 =C.sub.1-8 alkyl, n=0, or 1 to 3, (b) bringing the resultant solid carrier into a first contact with titanium tetrahalide, (c) treating the resultant titanium-containing solid product with an organic acid ester, and, finally, (d) bringing the treated solid product into a second contact with titanium tetrahalide; (B) another catalytic ingredient consisting of a trialkyl aluminium of the formula, AlR.sub.3.sup.4 wherein R.sup.4 =C.sub.

Abstract: An ethylene polymer is produced with an excellent yield by bringing a feed containing ethylene into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound with a reaction product of an aluminum halide with an organic silicon compound of the formula, R.sup.1.sub.n Si(OR.sup.2).sub.4-n, wherein R.sup.1 =C.sub.1-8 alkyl or phenyl, R.sup.2 =C.sub.1-8 alkyl and n=1, 2 or 3 and (b) by bringing the resultant solid reaction product into contact with titanium tetrahalide and (B) another catalytic ingredient consisting of at least one trialkyl aluminum.

Abstract: Poly.alpha.-olefin, for example, polypropylene, is produced with an excellent yield by bringing, in the presence of an organic acid ester, a feed, containing at least one .alpha.-olefin having 3 or more carbon atoms, for example, propylene, into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound of the formula, R.sup.3 MgX wherein R.sup.3 =C.sub.1-8 alkyl and X=halogen, with a reaction product of an aluminium halide with an organic silicon compound of the formula, R.sub.n.sup.1 Si(OR.sup.2).sub.4-n, wherein R.sup.1 =C.sub.1-8 alkyl or phenyl, R.sup.2 =C.sub.

Abstract: An .alpha.-olefin polymer having an excellent H.I. is produced with a high yield by bringing, in the presence of an organic acid ester, a feed containing at least one .alpha.-olefin, having 3 or more carbon atoms, into contact with a catalyst composed of:a solid catalytic ingredient which has been prepared in such a manner that an aluminosiloxy compound of the formula, ##STR1## wherein X.sup.1 represents a chlorine atom, a bromine atom or an iodine atom, is reacted with a Grignard compound of the formula R.sup.1 MgX.sup.2 [II] wherein R.sup.1 represents an alkyl radical having 1 to 8 carbon atoms and X.sup.2 represents a halogen atom, the resultant solid reaction product is brought into contact with a titanium tetrahalide, the resultant titanium-containing solid product is treated with an organic acid ester, and the treated solid product is brought into contact with a titanium tetrahalide; anda trialkyl aluminum.

Abstract: An ethylene polymer is produced with an excellent yield by bringing a feed containing ethylene into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound with an aluminium halide-tetraalkoxysilane reaction product and (b) bringing the resultant reaction product into contact with titanium tetrahalide and; (B) another catalytic ingredient consisting of a trialkyl aluminium.

Abstract: Poly-.alpha.-olefin having an excellent H. I. is produced with an excellent yield by bringing, in the presence of an organic acid ester, a feed, containing at least one .alpha.-olefin having 3 or more carbon atoms, into contact with a catalyst which comprises (A) a solid catalytic ingredient prepared (a) by reacting a Grignard compound with an aluminium halide-tetraalkoxysilane reaction product, (b) bringing the resultant reaction product into a first contact with titanium tetrahalide, (c) treating the resultant titanium-containing solid product with an organic acid ester, and, finally, (d) bringing the treated solid product into a second contact with titanium tetrahalide, and; (B) another catalytic ingredient consisting of a trialkyl aluminium.

Abstract: A sulfur-curable acrylic rubber composition is provided which comprises [I] 100 parts of an acrylic rubber resulting from the copolymerization in the presence of a radical initiator of (1) 30 to 89.5% by weight of at least one alkyl acrylate with the alkyl group containing 1 to 8 carbon atoms, (2) 0.5 to 10% by weight of at least one monomer of the general formula ##STR1## wherein R.sub.1 represents a hydrogen atom or a methyl group, and R.sub.2 and R.sub.3, independently from each other, represent an alkyl group containing 1 to 3 carbon atoms, (3) 10 to 60% by weight of at least one alkoxyalkyl acrylate with the alkoxy group containing 1 to 4 carbon atoms and the alkylene group containing 1 to 4 carbon atoms, and 0 to 30% by weight of at least one of monovinyl and monovinylidene unsaturated compounds other than the said compounds; and [II] 1 to 5 parts by weight of a metal compound, and [III] 0.2 to 5 parts by weight, as sulfur, of at least one of sulfur and sulfur-containing organic compounds.

Abstract: A process for producing a sulfur-curable acrylic rubber is provided which comprises radical-copolymerizing (1) an alkyl acrylate with (2) an alkenyl acrylate or methacrylate, or radical-copolymerizing (1) an alkyl acrylate, (2) an alkenyl acrylate or methacrylate, (3) an alkoxyalkyl acrylate and optionally (4) acrylonitrile. These acrylic rubbers can be cured at a rate as fast as those for curing diene-type rubbers, and the cured products exhibit superior properties without long heat-treatment after curing.

Abstract: Butadiene polymers containing 70% or more of 1,2-structure and a relatively low melting point are produced by polymerizing 1,3-butadiene in the presence of a catalyst which has been prepared by admixing (A) an organic solvent solution containing 1,3-butadiene, a cobalt compound and an organoaluminium compound; (B) an amide compound of the formula (2) or (3): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are respectively an H atom, aliphatic hydrocarbon radical of 1 to 7 carbon atoms or aromatic hydrocarbon radical of 6 or 7 carbon atoms, R.sub.3 is H or an aliphatic hydrocarbon radical of 1 to 3 carbon atoms and n is 2 to 5, and; (C) carbon disulfide.

Abstract: A process for producing a sulfur-curable acrylic rubber is provided which comprises radical-copolymerizing (1) an alkyl acrylate with (2) an alkenyl acrylate or methacrylate, or radical-copolymerizing (1) an alkyl acrylate, (2) an alkenyl acrylate or methacrylate, (3) an alkoxyalkyl acrylate and optionally (4) acrylonitrile. These acrylic rubbers can be cured at a rate as fast as those for curing diene-type rubbers, and the cured products exhibit superior properties without long heat-treatment after curing.