At present, the commonly used impact modifiers for PVC are chlorinated polyethylene (CPE),
polyacrylate (ACR), ethylene-vinyl acetate copolymer (EVA), methyl methacrylate-butadiene-
styrene terpolymer (MBS)。 all of which belong to rubber elastomer type impact modifiers.
1.Chlorinated Polyethylene (CPE)
CPE is chlorinated from HDPE，it is a good impact modifier for PVC. because CPE molecule
does not contain double bonds so haves good weather resistance, and because contain chlorine
so has flame resistance, because its low cost, excellent performance and wide application range.
So CPE is still one of the main application varieties of impact modifiers.
2 Polyacrylates (ACR)
ACR impact modifiers belong to core-shell copolymers. The core of ACR impact modifiers is a kind
of low-crosslinking acrylate rubber polymer, and the shell is a methyl methacrylate graft copolymer.
This modifier not only improves the impact resistance, but also acts as a ACR processing aid to
promote the gelation and plasticization of PVC resin.
3 Ethylene-Vinyl Acetate Copolymer (EVA)
EVA is a random copolymer of ethylene (E) and vinyl acetate (VAc). It is a rubber-like elastomer
similar to CPE. Although the modification effect and weatherability of EVA are good, but the application
of EVA in PVC profiles and pipes is obviously decreasing due to the low welding strength and low
notch impact strength of the profiles formed by EVA at high temperature. It has been replaced by
CPE and ACR.
4 Methyl methacrylate-butadiene-styrene terpolymer (MBS)
MBS as impact modifier be used on almost all transparent PVC products .Its dosage is generally between
8 and 15 phr. Because MBS contains double bonds,so it has poor weather resistance, so it is seldom used
in outdoor PVC profiles and pipes.