BS 771:1 992 pdf download.Phenolic moulding materials.
3 Definitions For the purposes of this International Standard, the following definitions apply.
3.1 phenolic moulding material thermosetting material based on a phenolic resin and used in the manufacture of thermoset- moulded articles. Other ingredients such as fillers, plasticizers, catalysts and colorants may be incorporated
3.2 phenolic resin generic term for a class of resins made by the polycondensation of phenol, and/or its homologues and/or derivatives of phenol or its homologues, with aldehydes or ketones. These thermosetting resins can be either novolaks (two-step PF 2) or resols (one-step PF 1) NOTE 1 Novolak resins require a crosslinking agent, generally hexamethylenetetramine.
4 Requirements Phenolic moulding materials complying with this specification shall meet the appropriate property requirements shown in Table 2. Though no specific limits are placed on the flow rate in Table 2, a suitable flow rate is essential for the satisfactory use of a phenolic moulding material and the flow rate shall therefore be specified in any contract.
The method of test and the flow rate value shall be as agreed by the interested parties. In addition, for some applications, it may be desirable for information to be made available on other properties of the moulding material, for example curing time, particle size or moisture content. If this is so, these properties and the method to be used shall be agreed by the interested parties.
5 Test specimens Bulk factor, moisture content, flow and particle size shall be measured on the moulding material itself. Other properties shall be determined on moulded test specimens prepared in accordance with ISO 295. It is permissible to machine test specimens from sheet (see ISO 2818) moulded under the moulding conditions of ISO 295, as long as it can be shown that the test specimens give results which do not differ significantly from those with moulded test specimens.
6 Methods of test
6.1 Determination of specific gravity See ISO 1183, method A. Test specimens may be prepared from any moulded plate or bar. At least two test specimens shall be used for the determination.
6.2 Determination of flexural stress at rupture See ISO 178. Five test specimens of length not less than 80 mm, of width 10 mm and of thickness 4 mm shall be used. For both moulded bars and test specimens machined from material moulded in the form of a plate, the load shall be applied parallel to the direction of moulding pressure. The testing speed shall be 2,0 mm/min土0,2 mm/min.
6.3 Determination of Charpy impact strength See ISO 179. For both moulded bars and test specimens machined from material moulded in the form of a plate, the load shall be applied parallel to the direction of moulding pressure.
6.3.1 Charpy notched impact strength See ISO 179, method 3C. Five test specimens shall be used for the determination.
6.3.2 Charpy unnotched impact strength See ISO 179, method 3D. Five test specimens shall be used for the determination.BS 771 pdf download.