Claims
- 1. In a process for manufacturing articles of filter paper, the process including: effecting mechanical working of a piece of filter paper to form a seam at which two parts of the piece of filter paper are joined together, the mechanical working resulting in the formation of weak points at the seam; and strengthening the paper with the aid of a wet strengthener of cross-linked cationic polyalkylenimines, the improvement wherein said step of strengthening comprises applying the wet strengthener only to the regions of the weak points after said step of effecting mechanical working.
- 2. Process as defined in claim 1 wherein the wet strengthener is applied in measured doses.
- 3. Process as defined in claim 1, wherein said step of effecting mechanical working comprises effecting a relief printing before said step of applying the wet strengthener, and further comprising effecting a heat treatment after said step of applying the wet strengthener to harden said strengthener.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3438213 |
Oct 1984 |
DEX |
|
Parent Case Info
This is a continuation-in-part of application Ser. No. 788,736, filed Oct. 17, 1985, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3444791 |
Honsel |
May 1969 |
|
3479203 |
Broadhurst |
Nov 1969 |
|
Foreign Referenced Citations (3)
Number |
Date |
Country |
0000448 |
Jan 1979 |
EPX |
3034955 |
Mar 1982 |
DEX |
3046036 |
Jul 1982 |
DEX |
Non-Patent Literature Citations (1)
Entry |
Hawley, G. G., The Condensed Chemical Dictionary, New York, Van Nostrand Reinhold Company, 1977, p. 239. |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
788736 |
Oct 1985 |
|