US 2025/0051560 A1 · RUBBER-REINFORCED VINYLAROMATIC (CO)POLYMERS AND PROCESS FOR THE PREPARATION THEREOF

Abstract

A rubber-reinforced vinyl aromatic (co)polymer having (a) a polymeric matrix comprising at least one vinyl aromatic monomer and at least one comonomer; (b) rubber particles obtained by a continuous mass process from functionalised low cis polybutadiene rubber dispersed therein, wherein: (i) the average volumetric diameter of the rubber particles is between 0.25 □m and 0.37 □m; (ii) the volume of the rubber particles having a diameter greater than 0.40 □m is between 20% and 50%, with respect to the total volume of the dispersed rubber particles; (iii) the ratio between rubber particles containing occlusions and rubber particles without occlusions is between 0.9 and 1.9. The aforementioned rubber-reinforced vinyl aromatic (co)polymer has high aesthetic properties, in particular in terms of gloss and gloss sensitivity, and mechanical properties, in particular in terms of impact resistance and puncture resistance. The aforementioned rubber-reinforced vinyl aromatic (co)polymer may be used in various applications, like injection moulding.

Claims14

Dependent claims

A rubber-reinforced vinyl aromatic (co)polymer comprising:

(a) a polymeric matrix comprising at least one vinyl aromatic monomer and at least one comonomer;
(b) rubber particles obtained by a continuous mass process from functionalised low cis polybutadiene rubber (LCBR) dispersed therein, wherein:
(i) the average volumetric diameter of said rubber particles is between 0.25 □m and 0.37 □m;
(ii) the volume of said rubber particles having a diameter greater than 0.40 □m is between 20% and 50%, with respect to the total volume of the dispersed rubber particles;
and
(iii) the ratio between rubber particles containing occlusions and rubber particles without occlusions is between 0.9 and 1.9.

3 more elements

A process for the preparation of a rubber-reinforced vinyl aromatic (co)polymer, the process including the following steps:

(a) obtaining a functionalised low cis polybutadiene rubber (LCBR) with a weight average molecular weight (Mw) between 40000 g/mole and 110000 g/mole, in a low boiling solvent;
(b) discontinuously exchanging the low boiling solvent with a vinyl aromatic monomer;
(c) storing the solution of functionalised low cis polybutadiene rubber (LCBR) in vinylaromatic monomer in a buffer tank, according to the functionalised low cis polybutadiene rubber (LCBR) grade obtained;
(d) feeding an aliquot of the solution of functionalised low cis polybutadiene rubber (LCBR) in vinylaromatic monomer stored in the buffer tank to a vessel and add a further aliquot of vinyl aromatic monomer to reach the desired concentration of rubber in the reaction mixture, at least one solvent, at least one radical polymerisation initiator, at least one chain transfer agent and further conventional additives;
(e) continuously feeding the solution obtained in step (d) to a first plug flow reactor (PFR) (R1) and immediately before entering said first reactor (R1) feeding a stream containing at least one comonomer;
(f) continuously feeding the reaction mixture leaving said first reactor (R1) to a second plug flow reactor (PFR) (R2) to which it is also continuously fed a solution of at least one chain transfer agent in solvent;
and
(g) recovering the rubber-reinforced vinyl aromatic (co)polymer from the polymerisation plant;
whereby the weight average molecular weight (Mw) of the functionalised low cis polyutadiene rubber (LCBR) (expressed in g/mole), the amount of chain transfer agent fed to the first plug flow reactor (PFR) (R1) [step (e)] (expressed in ppm, i.e. amount by weight of chain transfer agent fed with respect to the total weight of the compounds fed in said [step (e)]) and the average volumetric diameter of the functionalised low cis polybutadiene rubber (LCBR) particles (expressed in □m) are linked by the following relation:
0.5
(
g
/
moles
)
*
ppm
µm
3
≤
(
M
w
)
⁢
LCBR
*
Chain
⁢
transfer
⁢
agent
⁢
in
⁢
R
⁢
1
(
Average
⁢
volumetric
⁢
diameter
⁢
of
⁢
rubber
⁢
particles
)
3
≤
1.6
(
g
/
moles
s
)
*
ppm
µm
3
,

62 more elements

Dependencies are inferred from the claim text.

Rubber-reinforced vinylaromatic (co)polymers and process for the preparation thereof

Life of this patent

Rubber-reinforced vinylaromatic (co)polymers and process for the preparation thereof

Life of this patent

Abstract

Claims14