Compositions comprising LDPE, polypropylene and functionalised polyolefins
The invention provides a polymer composition comprising (i) an LDPE; (ii) a polypropylene; (iii) polyolefin (A) comprising epoxy groups; and (iii) polyolefin (B) comprising carboxylic acid groups and/or precursor thereof.
1 . A polymer composition comprising:
(i) an LDPE in an amount of 40 to 85 wt %, relative to the total weight of the polymer composition;
(ii) a polypropylene in an amount of 5 to 45 wt %, relative to the total weight of the polymer composition;
(iii) polyolefin (A) comprising epoxy groups; and
(iv) polyolefin (B) comprising carboxylic acid groups and/or precursor thereof;
wherein one of polyolefin (A) and polyolefin (B) is a polyethylene and wherein polyolefin (A) and/or polyolefin (B) are each present in an amount of 1.0 to 10.0 wt %, relative to the total weight of the polymer composition;
wherein the LDPE (i) is not crosslinked and the polypropylene (ii) is not crosslinked; and
wherein the composition consists of LDPE (i), polypropylene (ii), polyolefin (A), and polyolefin (B) as the only polymer components.
2 . The polymer composition as claimed in claim 1 , wherein the LDPE is present in an amount of 50 to 80 wt %, relative to the total weight of the polymer composition.
3 . The polymer composition as claimed in claim 1 , wherein the polypropylene is present in an amount of 10 to 35 wt %, relative to the total weight of the polymer composition.
4 . The polymer composition as claimed in claim 1 , wherein polyolefin (A) and/or polyolefin (B) are each present in an amount of 1.5 to 8.0 wt %, relative to the total weight of the polymer composition.
5 . The polymer composition as claimed in claim 1 , wherein the carboxylic acid groups and/or precursors thereof are grafted to said polyolefin (B).
6 . The polymer composition as claimed in claim 1 , wherein the epoxy groups are present in the form of an epoxy containing comonomer.
7 . The polymer composition as claimed in claim 6 , wherein said epoxy containing comonomer is selected from the group consisting of 1,2-Epoxy-9-decene, 1,2-epoxy-5-hexene, 3,4-epoxy-1-butene, glycidyl methacrylate, glycidyl acrylate, and allyl glycidyl ether.
8 . The polymer composition as claimed in claim 1 , wherein one of polyolefin (A) and polyolefin (B) is a polyethylene and the other of polyolefin (A) and polyolefin (B) is a polypropylene.
9 . The polymer composition as claimed in claim 1 , wherein the carboxylic acid group precursor is an ester or an anhydride.
10 . The polymer composition as claimed in claim 1 , wherein the carboxylic acid groups and/or precursor thereof is at least one of acrylic acid, maleic anhydride (MAH), or an alkyl (meth)acrylate.
11 . The polymer composition as claimed in claim 1 , wherein polyolefin (A) is a polyethylene.
12 . The polymer composition as claimed in claim 1 , wherein polyolefin (B) is a polypropylene.
13 . The polymer composition as claimed in claim 12 , wherein said polypropylene has a melting temperature (Tm) of greater than 140° C.
14 . The polymer composition as claimed in claim 1 , wherein said polypropylene (ii) is a propylene homopolymer.
15 . The polymer composition as claimed in claim 1 , wherein said composition comprises less than 0.5 wt % peroxide, relative to the total weight of the polymer composition as a whole.
16 . A process for preparing the polymer composition as defined in claim 1 , wherein said process comprises heating said polymer composition to a temperature greater than the melting point of at least the major polymer component(s) of the composition.
17 . The process as claimed in claim 16 , wherein said process does not use peroxide.
18 . A cable comprising one or more conductors surrounded by at least one layer, wherein said layer comprises the polymer composition as defined in claim 1 .
19 . The cable as claimed in claim 18 , where said one or more conductors are surrounded by at least an inner semiconductive layer, an insulation layer, and an outer semiconductive layer, in that order.
20 . The cable as claimed in claim 18 , wherein said layer comprising said polymer composition is an insulation layer.
21 . The cable as claimed in claim 18 , wherein said cable is non-crosslinked.
22 . A process for producing a cable, the process comprising: applying on one or more conductors, a layer comprising the polymer composition as defined in claim 1 .
23 . A method of use of the polymer composition as defined in claim 1 , the method comprising using the polymer composition in the manufacture of an insulation layer or semi-conductive layer in a cable.