A method for producing a hydrogenated conjugated diene polymer latex includes: a hydrogenation step of dissolving or dispersing a hydrogenation catalyst containing a platinum group element in a latex of a conjugated diene polymer to hydrogenate a carbon-carbon unsaturated bond in the conjugated diene polymer; and an insoluble complex formation step of complexing the platinum group element in the latex with a complexing agent to form an insoluble complex, wherein pH of the latex at the insoluble complex formation step is controlled in a range of 5.0 to 8.0.

The present invention is directed to a method of making a functionalized elastomer, comprising the step of polymerizing monomers comprising a conjugated diene monomer in the presence of a lathanide-based coordination polymerization catalyst activated with a magnesium compound of formula 1 ##STR00001## where R.sup.1 is phenylene, or a linear or branched alkane diyl group containing 2 to 10 carbon atoms, or a combination of one or more phenylene groups and one or more linear or branched alkane diyl groups containing 1 to 10 carbon atoms; Q is of formula 2 or 3 ##STR00002## where R.sup.2 is phenyl, or a linear or branched alkyl group containing 2 to 10 carbon atoms; ##STR00003## where R.sup.3 and R.sup.4 are independently phenyl or a linear or branched alkyl group containing 1 to 10 carbon atoms, or R.sup.2 and R.sup.3 taken together with the nitrogen atom represent a nitrogen containing heterocyclic group containing from 4 to 12 carbon atoms.

The present invention is directed to a method of making a functionalized elastomer, comprising the step of polymerizing monomers comprising a conjugated diene monomer in the presence of a lanthanide-based coordination polymerization catalyst activated with a magnesium compound of formula 1

Q-R.sup.1MgR.sup.1-Q1

where R.sup.1 is phenylene, or a linear or branched alkane diyl group containing 2 to 10 carbon atoms, or a combination of one or more phenylene groups and one or more linear or branched alkane diyl groups containing 1 to 10 carbon atoms; Q is of formula 2 or 3

SR.sup.22

where R.sup.2 is phenyl, or a linear or branched alkyl group containing 2 to 10 carbon atoms;

##STR00001##

where R.sup.3 and R.sup.4 are independently phenyl or a linear or branched alkyl group containing 1 to 10 carbon atoms, or R.sup.2 and R.sup.3 taken together with the nitrogen atom represent a nitrogen containing heterocyclic group containing from 4 to 12 carbon atoms.

The present invention aims to provide rubber compositions for tires that contain a natural rubber achieving a balanced improvement in abrasion resistance, breaking performance, and processability to achieve a balanced improvement in abrasion resistance, breaking performance, and processability, and also provide pneumatic tires containing such rubber compositions for tires. Included is a rubber composition for tires comprising a modified natural rubber prepared by treating natural rubber latex with a proteolytic enzyme, and then treating the treated natural rubber latex with a lipolytic enzyme and/or a phospholipid degrading enzyme. Also included is a rubber composition for tires, comprising a modified natural rubber prepared by centrifuging natural rubber latex to recover a latex fraction comprising latex particles having an average particle size of 0.25 ?m or less.

The present invention aims to provide rubber compositions for tires that contain a natural rubber achieving a balanced improvement in abrasion resistance, breaking performance, and processability to achieve a balanced improvement in abrasion resistance, breaking performance, and processability, and also provide pneumatic tires containing such rubber compositions for tires. Included is a rubber composition for tires comprising a modified natural rubber prepared by treating natural rubber latex with a proteolytic enzyme, and then treating the treated natural rubber latex with a lipolytic enzyme and/or a phospholipid degrading enzyme. Also included is a rubber composition for tires, comprising a modified natural rubber prepared by centrifuging natural rubber latex to recover a latex fraction comprising latex particles having an average particle size of 0.25 ?m or less.

A method for producing a polymer latex, includes: a stirring step of adding water to a polymer solution obtained by dissolution of a synthetic rubber in an organic solvent, to allow water to be stirred in the polymer solution, thereby providing a water-stirred polymer solution (A); an aqueous phase removal step of removing an aqueous phase from the water-stirred polymer solution (A), thereby providing an aqueous phase-removed polymer solution (B); an emulsification step of mixing the aqueous phase-removed polymer solution (B) with an aqueous solution including a surfactant, for emulsification in water, thereby obtaining an emulsified liquid (C); a solvent removal step of removing an organic solvent in the emulsified liquid (C); and a concentration step of concentrating the emulsified liquid from which the organic solvent is removed (D).

Methods for increasing the extractable rubber content of non-Hevea plant matter that entail the use of particular forms of hammer milling and/or roller milling in an increase in the amount of rubber that can be extracted from the resulting plant matter such as by organic solvent extraction or aqueous extraction are provided. In certain embodiments, the methods are for increasing the extractable rubber content of guayule plant matter, and entail the use of particular forms of hammer milling in combination with roller milling and flaking to increase the amount of rubber that can be extracted from the guayule plant matter such as by organic solvent extraction or aqueous extraction.

Methods for increasing the extractable rubber content of non-Hevea plant matter that entail the use of particular forms of hammer milling and/or roller milling in an increase in the amount of rubber that can be extracted from the resulting plant matter such as by organic solvent extraction or aqueous extraction are provided. In certain embodiments, the methods are for increasing the extractable rubber content of guayule plant matter, and entail the use of particular forms of hammer milling in combination with roller milling and flaking to increase the amount of rubber that can be extracted from the guayule plant matter such as by organic solvent extraction or aqueous extraction.

The present invention aims to provide rubber compositions for tires that contain a natural rubber achieving a balanced improvement in abrasion resistance, breaking performance, and processability to achieve a balanced improvement in abrasion resistance, breaking performance, and processability, and also provide pneumatic tires containing such rubber compositions for tires. Included is a rubber composition for tires comprising a modified natural rubber prepared by treating natural rubber latex with a proteolytic enzyme, and then treating the treated natural rubber latex with a lipolytic enzyme and/or a phospholipid degrading enzyme. Also included is a rubber composition for tires, comprising a modified natural rubber prepared by centrifuging natural rubber latex to recover a latex fraction comprising latex particles having an average particle size of 0.25 ?m or less.

The present invention aims to provide rubber compositions for tires that contain a natural rubber achieving a balanced improvement in abrasion resistance, breaking performance, and processability to achieve a balanced improvement in abrasion resistance, breaking performance, and processability, and also provide pneumatic tires containing such rubber compositions for tires. Included is a rubber composition for tires comprising a modified natural rubber prepared by treating natural rubber latex with a proteolytic enzyme, and then treating the treated natural rubber latex with a lipolytic enzyme and/or a phospholipid degrading enzyme. Also included is a rubber composition for tires, comprising a modified natural rubber prepared by centrifuging natural rubber latex to recover a latex fraction comprising latex particles having an average particle size of 0.25 ?m or less.