Masterbatch comprising a cyclic ketone peroxide

Abstract

Masterbatch comprising a dimeric and/or trimeric cyclic ketone peroxide dispersed in a polymeric matrix with a porosity, expressed as percentage of voids on the volume of the matrix, of 0.1-80 vol %, wherein said masterbatch comprises, per 100 g of polymeric matrix, 1-30 g dimeric and/or trimeric cyclic ketone peroxide and less than 0.20 g saturated hydrocarbons with 17-51 carbon atoms.

Claims

1. A masterbatch comprising 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane dispersed in a polymeric matrix with a porosity, expressed as percentage of voids on the volume of the matrix, of 0.1-80 vol %, wherein said masterbatch comprises, per 100 g of polymeric matrix, 1-30 g 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane and less than 0.20 g saturated hydrocarbons with 17-51 carbon atoms.

2. The masterbatch according to claim 1, comprising, per 100 g of a polymeric matrix, less than 0.15 g saturated hydrocarbons with 17-51 carbon atoms.

3. The masterbatch according to claim 2, comprising, per 100 g of a polymeric matrix, less than 0.10 g saturated hydrocarbons with 17-51 carbon atoms.

4. The masterbatch according to claim 1, wherein the resulting masterbatch comprises 4-18 g of 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane per 100 g of polymeric matrix.

5. The masterbatch according to claim 1, wherein the polymeric matrix has a porosity of 10-60 vol %.

6. The masterbatch according to claim 1, wherein the polymeric matrix consists for at least 50 wt % of polypropylene, polyethylene, ethylene vinyl acetate polymer or any mixtures thereof.

7. The masterbatch according to claim 6, wherein the polymer is a polymerization reactor grade or extruded porous grade.

8. A process for the preparation of a masterbatch according to claim 1, comprising (i) providing a polymeric matrix with a porosity, expressed as percentage of voids on the volume of the matrix, of 0.1-80 vol % and (ii) impregnating said polymeric matrix with a formulation comprising 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane and one or more solvents.

9. A method for the modification of a polymer, comprising adding the masterbatch according to claim 1 to a polymer.

10. The method according to claim 9, wherein the modification involves cracking of polypropylene homopolymers and/or copolymers of propylene and ethylene.

11. The method according to claim 9, wherein the modification involves the introduction of long chain branches or crosslinking of polyethylenes.

Description

EXAMPLES

Example 1

(1) A formulation of 24 wt % cyclic trimeric methyl ethyl ketone (MEK) peroxide in pentane was absorbed on polypropylene with a porosity of 36 vol %, by slowly adding the formulation to said polypropylene while stirring.

(2) After stirring for 25 minutes, the high volatile pentane was stripped off the formulation by passing air through the sample, followed by evacuation of the sample to around 10 mbar at room temperature. This resulted in a masterbatch comprising 7 wt % trimeric MEK peroxide on polypropylene.

(3) A masterbatch comprising 13.3 wt % trimeric MEK peroxide was obtained by repeating the above procedure.

(4) The porosity of the polypropylene was determined by mercury intrusion according to ISO 15901-1: Evaluation of pore size distribution and porosimetry of solid materials by mercury porosimetry and gas adsorptionPart 1: Mercury porosimetry. The instrument used was a Micromeritics Autopore 9505 Porosimeter in the pressure range from vacuum up to 220 MPa. Prior to the measurement, the polypropylene was dried by vacuum at 35 C. for 6 hours.

(5) The crystallization behavior of the peroxide in the masterbatchesfreshly prepared and after storage at 25 C. for several weekswere analyzed with differential scanning calorimetry (DSC). A cup containing the masterbatch was placed on dry ice, 80 C., and transferred into a pre-cooled DSC oven at 25 C. The transfer was carried out as fast as possible to avoid heating, and thus melting, of the possibly solidified peroxide. The first period of 10-20 minutes at 25 C. in the DSC oven was to evaporate the ice on the outside of the DSC pan. The samples were then heated to +35 C., with a heating rate of 2 C./min.

(6) No crystallization of peroxide was observed with this test in both masterbatches, not even after 5 weeks of storage at 25 C.

(7) The masterbatches were also subjected to the Modified Trauzl test according to the UN Recommendations on the Transport of Dangerous Goods. A standardized amount of sample was weighed into a glass vial and placed in a lead block. The lead block is provided with a standardized bore hole. A blast cap with 0.6 gram of a high explosive, PETN, was placed in the centre of the sample. The tests were carried out in a concrete cell, all remote controlled.

(8) The expansion of the lead block, after subtracting the expansion of an inert substance, is a measure for the explosive power of the sample. Tests were carried out using 4.5 gram sample.

(9) The Modified Trauzl test was selected to discriminate between crystallized and dissolved cyclic trimeric MEK-peroxide because the crystallized peroxide shows detonative properties and this will give a high expansion of the lead block.

(10) The explosive power as measured with this test was equal to the explosive power of a commercial sample of trimeric cyclic MEK peroxide in Isopar M containing paraffin wax (Trigonox 301).

(11) This Example shows that wax-free masterbatches of cyclic trimeric methyl ethyl ketone peroxide according to the present invention exhibit safe characteristics. These characteristics are similar to commercially available wax-containing cyclic trimeric methyl ethyl ketone peroxide solutions.

Example 2

(12) Peroxide masterbatches were prepared by formulating cyclic trimeric MEK-peroxide solutions in Isopar M on the polypropylene used in Example 1. The final contents of cyclic trimeric MEK-peroxide (as pure peroxide) were 10 and 12 wt %. Caking cylinders (stainless steel, 4 cm internal diameter and 19 cm height) were filled with the different masterbatch materials (about 30 g). With a plunger a load of 0.23 kg was applied on top of each to simulate the pressure conditions as if 25 kg product would be packed in a bag in a cardboard box, or 4 bags stacked on top of one another on a pallet.

(13) The caking cylinders were stored in a circulation oven for 4 weeks at 35 C. After this period the loads were removed and the caking cylinders were opened carefully to release the materials in order to visually inspect if caking had occurred. In all tests no caking was observed, the materials were still free flowing.