Process for preparing vinyl based polymers and copolymers insoluble in their monomers

Claim 2

The process as claimed in claim 1 in which the polymerization reaction is a single stage polymerization carried out with moderate agitation.

Claim 3

The process as claimed in claim 1 in which the dispersion of the suspension of the aqueous solution of a portion of the catalytic system in the monomeric composition is carried out jointly with the initiation of polymerization under high turbulence to a conversion rate within the range of 1 to 50 percent in a first stage and then polymerizing with slow agitation sufficient to prevent reagglomeration of the polymer particles in a second stage.

Claim 4

The process as claimed in claim 4 in which the initial polymerization in the first stage is carried to a conversion rate within the range of 3 to 25 percent.

Claim 5

The process as claimed in claim 1 which includes the step or pre-polymerizing the dispersion of the suspension of the aqueous solution of at least a portion of the catalytic system in the monomer or comonomer composition under high turbulence to a conversion rate within the range of 1 to 30%, transferring the pre-polymerizate to a polymerizer and continuing polymerization to final polymerization under slow agitation sufficient to prevent reagglomeration of the polymer particles that are formed.

Claim 6

The process as claimed in claim 6 in which the pre-polymerization is carried to a conversion rate within the range of 3 to 15 percent.

Claim 7

The process as claimed in claim 1 which includes the additional step of dissolving the remainder of the catalytic system in a composition of the monomer or comonomers and carrying out the polymerization in one stage, as claimed in claim 3.

Claim 8

The process as claimed in claim 1 which includes the additional step of dissolving the remainder of the catalytic system in a composition of the monomer or comonomers and then carrying out the polymerization in two stages as claimed in claim 4.

Claim 9

The process as claimed in claim 1 which includes the additional step of dissolving the remainder of the catalytic system in a composition of the monomer or comonomers, and carrying out the polymerization with pre-polymerization as claimed in claim 6.

Claim 10

The process as claimed in claim 1 in which, when the catalytic system is formed of a number of water soluble components, the aqueous solution of separate cOmponents are separately introduced in the reaction mixture at various stages of the polymerization.

Claim 11

The process as claimed in claim 1, characterized by the fact that there is achieved in an essentially continuous manner, the dispersion in small amounts of a suspension of an aqueous solution of at least a part of a catalytic system in the whole or part of a monomeric or comonomeric composition of the vinyl type, then continuously polymerizing the said composition on contact with a determined quantity of monomeric composition and of a quantity of polymer or copolymer, the latter being previously prepared by the same process, the reaction medium being maintained under moderate agitation in the polymerization reactor, while in an essentially continuous manner extracting the polymers or copolymers formed and then degassing in order to separate them from the unreacted monomeric composition.

Claim 12

The process as claimed in claim 12 characterized by the fact that in the polymerization reactor the polymer/monomer weight ratio is maintained at values between 0.3 and 9 by eventually adding a complementary monomeric composition free of catalyst.

Claim 13

The process as claimed in claim 12 characterized by the fact that in the polymerization reactor the polymer/monomer weight ratio is maintained at values between 1 and 4 by eventually adding a complementary monomeric composition free of catalyst.

Claim 14

The process as claimed in claim 1 characterized by the fact that in a pre-polymerizer there are achieved jointly in an essentially continuous manner, the dispersion and in small quantities of a suspension of an aqueous solution of at least a part of the catalytic system in the whole or part of a monomeric or comonomeric composition of the vinyl type, and the pre-polymerization of the thus constituted reaction medium under high turbulence agitation, up to a conversion rate generally comprised between 1 and 20 percent, then after transfer into a polymerizer continuously polymerizing the prepolymerizate on contact with a determined quantity of monomeric composition and of a quantity of previously prepared polymer or copolymer, the reaction medium being maintained under slow agitation sufficient to avoid the reagglomeration of the altering grains while continuously extracting the polymers or copolymers formed as also their degassing in order to separate them from the unreacted monomeric composition.

Claim 15

The process as claimed in claim 15 characterized by the fact that in the polymerizer the polymer/monomer ratio by weight is maintained at values between 0.3 and 9 by adding a complementary monomeric composition free of catalyst.

Claim 16

The process as claimed in claim 1 characterized by the fact that the start of the polymerization operation is achieved in the presence of a sufficient amount of catalytic aqueous solution in finely divided form to provide an aqueous phase different from the organic phase.

Claim 17

The process as claimed in claim 1 characterized by the fact that through the medium of the suspension of the catalytic aqueous solution, there is introduced into the reaction medium an emulsifier selected from the group consisting of emulsifiers of the cationic type, of the anionic type, of the non-ionic type.

Claim 18

The process as claimed in claim 18 in which the emulsifier of the cationic type is a quaternary ammonium salt.

Claim 19

The process as claimed in claim 18 in which the emulsifier of the anionic type is an alkaline salt of a sulphonate or sulphosuccinate.

Claim 20

The process as claimed in claim 18 in which the emulsifier of the non-ionic type is an ethylene polyoxide grafted by styrene or vinyl acetate.

Claim 21

The process as claimed in claim 1 characterized by the fact that the polymerization is carried out in a medium buffered to a pH from 2 to 10.

Claim 22

The process as claimed in claim 1 characterized by the fact that the polymerization is carried out in a medium buffered to a pH from 4 to 8.5.

Claim 23

The process as claimed in claim 1 characterized by the fact that monomeric or comonomeric compositions are selected from the group consisting of vinyl chloride; vinyl chloride and vinyl acetate; vinyl chloride and at least an olefin; vinyl chloride and vinylidene chloride; vinyl chloride, vinyl acetate and at least one olefin, in which the copolymers formed are essentially insoluble in the initial compositions.

Claim 24

The process as claimed in claim 24 in which the olefin is selected from the group consisting of ethylene, propylene, butene-1, butene-2, isobutene and methyl-4-pentene-1.

Claim 25

The process as claimed in claim 1 characterized by the fact that a catalytic system is used in which at least one of the components is insoluble in the organic phase of the reaction medium and soluble in the aqueous phase.

Claim 26

The process as claimed in claim 1 characterized by the fact that the catalytic system is selected from the group formed of persalts or hydrogen peroxide combined with a mineral or organic reducing agent; catalytic systems one of the components of which is soluble in vinyl chloride and slightly water soluble, the other component being water soluble and insoluble in vinyl chloride; systems formed by reducing components soluble in vinyl chloride and sparingly water soluble and water soluble oxidizing activation components.

Claim 27

The process as claimed in claim 1 characterized by the fact that the polymerization is carried out at temperatures within the range of 0* to 90* C.

Claim 28

The process as claimed in claim 1 in which the polymerization is carried out at a temperature within the range of 50* to 70* C.

Claim 29

The process as claimed in claim 1 in which the polymerization temperature is below 0* C. when addition is made of an anti-gelling agent.

Claim 30

The process as claimed in claim 15 in which the conversion rate is within the range of 2 to 10 percent.

Claim 31

The process as claimed in claim 16 in which the polymer to monomer ratio by weight is maintained within the range of 1 to 4.