received by the International Bureau on 12 February 2013 (12.02.13)

1. A high activity olefin polymerization catalyst comprising a boron-containing silica support, characterized in that the support is heat treated in combination with a chemical treatment using a boron compound wherein the weight of boron relative to the support is 0.5 to 0.7%. 5 2. The catalyst according to claim 1, wherein the boron compound is boron halide.

3. The catalyst according to claim 1 or 2, wherein the boron compound is boron trichloride.

4. The catalyst according to any of the preceding claims, wherein the weight of boron relative to the catalyst is 0.1 to 0.5%.

5. The catalyst according to any of the preceding claims, wherein the catalyst has chemical 0 compositions comprising:

- Boron 0.1-0.5% wt

Titanium 4-6% wt

Magnesium 2-6% wt

- Chloride 15-25% wt

15 6. A preparation process of a high activity olefin polymerization catalyst comprising the boron- containing silica support, the process comprising the following steps:

(a) treating the silica with heat under an inert atmosphere;

(b) chemically treating the silica obtained from (a) using a boron compound to achieve the boron-containing silica support; and

20 (c) preparing the catalyst from the silica support obtained from (b)

wherein the catalyst has the weight of boron relative to the support is 0.5 to 0.7%.

7. The preparation process of the catalyst according to claim 6, wherein the boron compound is boron halide.

& The preparation process of the catalyst according to claim 6 or 7, wherein the boron 25 compound is boron trichloride.

9. The preparation process of the catalyst according to any one of claims 6 to 8, wherein step (b) has the mole ratio of silica per the boron compound of 100-300 : 5-9.

10. The preparation process of catalyst according to claim 9, wherein step (b) has the mole ratio of silica per the boron compound of 200:7.

, 30 1 1. The preparation process of the catalyst according to any one of claims 6 to 10, wherein the catalyst has the weight of boron relative to the catalyst is 0.1 to 0.5%. 15

The preparation process of the catalyst according to any one of claims 6 to 11 , wherein the catalyst has chemical compositions comprising:

- Boron 0.1-0.5% wt

Titanium 4-6% wt

Magnesium 2-6% wt

- Chloride 15-25% wt