塑料板块9月4日跌2.03%，上纬新材领跌，主力资金净流出4.05亿元

Group 1 - The plastic sector experienced a decline of 2.03% on September 4, with Shangwei New Materials leading the drop [1][2] - The Shanghai Composite Index closed at 3765.88, down 1.25%, while the Shenzhen Component Index closed at 12118.7, down 2.83% [1] - Key stocks in the plastic sector showed varied performance, with Hangzhou Gaoxin rising by 19.99% and Shangwei New Materials falling by 13.94% [1][2] Group 2 - The net outflow of main funds in the plastic sector was 405 million yuan, while retail investors saw a net inflow of 477 million yuan [2][3] - Major stocks like Jinfat Technology and Hangzhou Gaoxin had significant net inflows from main funds, while others like Dazhongnan and Fusheng Technology experienced net outflows [3]