| 摘要 |
1,059,983. Laminates. HUYCK CORPORATION. April 8, 1964 [April 16, 1963], No. 14603/64. Heading B5N. [Also in Divisions D1 and D2] A papermaker's felt for the wet press section of a papermaking machine comprises a permeable base layer in the form of an endless belt the material of the base layer being of relatively low compressibility under normal wet press pressures and providing a substantial voidage for the reception of water constituted by passageways in the base layer; a permeable facing layer coextensive with the base layer is united to it and is of material which is relatively easily compressed and which has passageways of relatively small size compared with the base layer. The base layer may be woven as an endless belt and may include yarns of polyamides, alone or with cotton, and polyesters. The facing layer may be a carded or Garnetted fibrous web which may be needled to the base fabric or needled and then united adhesively thereto and comprises wool fibres or mixtures thereof with synthetic fibres, such as polyamides, polyesters or acrylic fibres. The degree of compressibility of the base layer is dependent upon the type of weave, the yarn count and twist and may be reduced by suitable aftertreatment. A nylon base fabric, for example, may be treated with melamine formaldehyde and then heat set. Alternatively such a fabric may be treated in a first stage with phenolic formaldehyde and in a second stage with an aldehyde donor with heat setting. A nylon and cotton fabric may be impregnated with a resorcinol formaldehyde and melamine formaldehyde to improve its resistance to compression. In order to prevent rewetting of the facing layer and possibly also of the web of paper after passage through the nip of the press rolls the fibres of the facing layer may be treated to provide water repellancy. Alternatively a barrier layer, which may be the adhesive, may be provided between the base and facing layers to restrict the return movement of water from the base to the facing layer after the nip pressure is released. A suitable adhesive referred to for uniting wool fibres to a base layer containing nylon with or without cotton is an adhesive of the family of phenol blocked isocyanate resins. These substances may also be used as a barrier layer where the facing and base layers are to be united by needling. The base layer may be formed to retain water or to allow its passage therethrough by suitably determining the sizes of the passages in the base fabric. |
