Caprolactam: Correlation
Prices it moves with, and why
Caprolactam, the monomer for nylon 6, is made from benzene via cyclohexanone, using ammonia and sulphuric acid. Benzene sets most of its cost, and the process yields large tonnages of ammonium sulphate fertiliser as a by-product.
Proxy US PPI: cyclic intermediate chemicals index (BLS base period) · monthly, Jan 2006 to Sep 2026There is no free public price for caprolactam itself, so this tab uses the closest public series as a stand-in. Read the numbers as an indication, not as the price of this exact item.
What its price moves with
Selected linkCaprolactam and Benzene
Monthly changes 0.50 moderate correlation 12-month changes 0.73 strong correlation Last 5 years 0.02 monthly changes Lead or lag +1 mo Benzene tends to lead by 1 month (r 0.56) Price function, Jan 2006 to Sep 2026 Caprolactam ≈ 116.6 × (Benzene)0.10 R² 0.02 On this fit, a 10% higher benzene price goes with a 1.0% higher caprolactam price over the long run. Units: index (BLS base period) and index (BLS base period). The fit is loose, so treat the function as a rough guide.Chart: Caprolactam and Benzene prices rebased to 100 at Jan 2006, log scale
Both prices rebased to 100 at Jan 2006, on a log scale so equal percentage moves look the same size.Chart: Caprolactam price against Benzene price, monthly, log scales, with fitted line
Each dot is one month; paler dots are older (2006), darker dots recent (2026); the ringed dot is the latest month. The dashed line is the fitted price function. Both axes are logarithmic.Benzene supplies the carbon ring of caprolactam, so its price sets most of the cost. The petrochemical proxy moves with the cyclic proxy at 0.50 monthly and 0.73 yearly, though the monthly tie has faded over the last five years.
moderate co-movement month to month · 249 months Show chartsNearly all caprolactam is polymerised into nylon 6 for fibres, tyre cord and engineering plastics. The broad resin index moves with the cyclic proxy at 0.38 monthly and 0.73 yearly.
weak co-movement month to month · 249 months Show chartsNeutralising the acid used in the process yields ammonium sulphate, whose fertiliser sales lower caprolactam's net cost. The nitrogen fertiliser proxy moves with the cyclic proxy at 0.24 monthly and 0.70 yearly.
weak co-movement month to month · 249 months Show chartsAmmonia makes the hydroxylamine that turns cyclohexanone into the oxime, and it ends up in the by-product fertiliser too. The same nitrogen fertiliser proxy applies, so the figures match those for ammonium sulphate: 0.24 monthly and 0.70 yearly.
weak co-movement month to month · 249 months Show chartsOleum and sulphuric acid drive the rearrangement step, so sulphur prices enter caprolactam costs. The sulphuric acid index moves with the cyclic proxy at 0.19 monthly and 0.60 yearly. Most of that acid ends up in the by-product.
little or none co-movement month to month · 225 months Show chartsMuch of the benzene for caprolactam comes from refinery reformers, so refinery economics affect supply. The refinery index moves with the cyclic proxy at 0.34 monthly and 0.74 yearly. Coke oven benzene is another source in Asia.
weak co-movement month to month · 249 months Show chartsHow to read these numbers
Correlation of monthly changes (the number in the coloured pill) compares how much each price moved, month by month, since 2006 or the first month both series exist. It runs from −1 to +1: near +1 the two usually rise and fall in the same months, near 0 there is no link, and a negative number means they tend to move in opposite directions. Above 0.7 is strong, 0.4 to 0.7 moderate, 0.2 to 0.4 weak.
12-month changes compare year-on-year moves, which shows whether two prices share the same cycles even when the month-to-month noise differs.
Price function is a straight-line fit of the two prices on logarithmic scales: price ≈ k × (partner price)β. β is how much this price moves, in per cent, for a 1% move in the partner over the whole period, and R² is the share of the variation the fit explains. Two prices that both drift up with inflation can fit well without any real link, so read it together with the monthly correlation.
Lead or lag checks whether the monthly correlation is clearly higher when one price is shifted by 1 to 6 months.
Correlation is not cause. The reasons on each card explain the economic link; the numbers show how strongly it has shown up in prices. Proxy series are US producer price indexes or related prices and can blur the real link.
Data: World Bank Commodity Price Data (Pink Sheet), October 2026; US Bureau of Labor Statistics producer price indexes, IMF primary commodity prices and US EIA prices via FRED, Federal Reserve Bank of St. Louis, retrieved November 2026. Calculations by this site.