| 摘要 |
The object of the invention is a method for producing a multi-layer filtering material (14), and a multi-layer filtering material (14). By using this method, at least one filtering layer (15) of natural fibres, such as wood pulp fibres and/or plastic fibres and binder material and/or binder fibres is formed by the dry forming technique and bonded by heat. According to the invention, the method further comprises the stages wherein at least one strengthening layer (16, 17) of natural fibres, such as wood pulp fibres and/or plastic fibres and binder material and/or binder fibres is formed by the dry forming technique, said strengthening layer being formed so as to be in contact with said at least one filtering layer (15) and being formed in connection with the forming of the filtering layer, said at least one strengthening layer being bonded with said at least one filtering layer in order to form a unity (14), said unity being formed in connection with the heat bonding of the filtering layer.
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