| 摘要 |
1501534 Non - woven fabric SAINTGOBAIN INDUSTRIES 6 April 1976 [30 April 1975] 13897/76 Heading D1R [Also in Division C3] A web of glass fibres is bonded by immersing it in a starch size containing a modified melamine - formaldehyde resin and polyvinyl acetate, draining it and drying it. The modified melamine - formaldehyde resin is obtained in the Examples by adding melamine over 12 minutes to a mixture of 36% formaldehyde, ethylene glycol and triethanolamine to give molar ratios of melamine to these ingredients of 1:6.75-10:4:0.33, the mixture is cooled to 35‹C when the turbidity point is 50‹C; H 2 SO 4 is added over 30 mins. and the mixture is kept for 90 mins. at pH 2 and 35‹C. the pH is adjusted to 7.2 with a further 0.33 moles (per mole of melamine) of triethanolamine, and NaOH as necessary and the mixture left at 70‹C for 5 hrs.; then 0.8 moles (per mole of melamine) of urea pellets are added. In further Examples there is used 1.2 moles of urea (Ex. 7); glycorol, di- or triethylene glycol, d - glucose or sucrose or sucrose/ethylene glycol mixture (Exs. 10 and 11): HCI, H 3 PO 4 , HNO 7 ,H - COOH or ClCH 2 COOH (Ex. 15). |
