I'm pretty sure it's more the natural fibres that need to be blocked. Something that is 100% acrylic can be "blocked" by being washed and dried in the machine. It helps to even things out etc.
OTN: Corona, Miter square blanket, Charity blankets
FO: Forest Canopy Shawl, Easy Baby Bootees, Kitty Pi, Ms. Marigold, Twinkle Toes, Josh's socks, Hedera socks, Spring Beret, Ashley's Birthday socks, Socks for the DBF's mom, grey socks for the DBF, my first socks, reversible cable scarf, ribbed hat for the BF, Manos Del Uruguay afghan, and a whole bunch of dishcloths!
I have never blocked acrylics. I even have a top I made over 15 years ago using a yarn from Sirdar which was 100% acrylic called the Terry look. It looks like terrycloth when knit up. It was light sport weight. I have thrown that top in the washer and the dryer and then folded it up and put it in the drawer. It has always held it's shape and I love to wear it. I finally got a hole in the ribbing on the back and so have to mend it before wearing again, but I figure on getting another 10 years or so from it.
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