The overall ratings of 6 Chemicals stocks are down on Portfolio Grader this week. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

PPG Industries, Inc. (PPG) gets weaker ratings this week as last week’s C drops to a D. PPG Industries, Inc. supplies products for the manufacturing, construction, automotive, chemical processing, and other industries worldwide. For more information, get Portfolio Grader’s complete analysis of PPG stock.

Minerals Technologies Inc. (MTX) experiences a ratings drop this week, going from last week’s C to a D. Minerals Technologies Inc. is a resource- and technology-based company that develops, produces, and markets a range of specialty mineral, mineral-based, and synthetic mineral products and supporting systems and services. The company also gets F’s in sales growth. For more information, get Portfolio Grader’s complete analysis of MTX stock.

RPM International Inc.’s (RPM) rating weakens this week, dropping to a D versus last week’s C. RPM International Inc. manufactures, markets, and sells various specialty chemical product lines. For more information, get Portfolio Grader’s complete analysis of RPM stock.

Kraton Performance Polymers, Inc. (KRA) is having a tough week. The company’s rating falls from a C to a D. Kraton Performance Polymers, Inc. produces engineered polymers and styrenic block copolymers. The company also gets F’s in sales growth, operating margin growth, earnings surprise, and free cash flow. For more information, get Portfolio Grader’s complete analysis of KRA stock.

Slipping from a D to a F rating, Tredegar Corporation (TG) takes a hit this week. Tredegar Corporation manufactures plastic films, elastics and laminate materials, mainly for personal and household care products and packaging and surface protection applications. The company also gets F’s in operating margin growth, earnings growth, earnings revisions, and earnings momentum. For more information, get Portfolio Grader’s complete analysis of TG stock.

Trecora Resources (TREC) declines this week from a C to a D. The company also gets F’s in sales growth, earnings revisions, and earnings surprise. For more information, get Portfolio Grader’s complete analysis of TREC stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.