Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1997-06-17
1998-11-10
Reddick, Judy M.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
523501, 523504, 523505, 524433, 524436, 524494, 524789, 524601, 524604, 524773, 524779, 524878, C08K 509
Patent
active
058345477
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a molding compound composition particularly suitable for low pressure molding, a molding compound containing the same, and a method for producing the molding compound.
BACKGROUND ART
A sheet molding compound (hereinafter referred to as the "SMC"), bulk molding compound (hereinafter referred to as the "BMC") are known conventional molding compounds. These materials are formed by impregnating reinforced fibers (reinforcements) such as glass fibers with a compound containing unsaturated polyester and various fillers. Immediately after adding a thickening agent such as magnesium oxide to the compound (i.e., when the compound is still low in viscosity), the compound is impregnated into the reinforced fibers, and thickened (matured) to a predetermined viscosity (about several hundred thousand poise). As a result, a molding compound is produced.
However, the initial thickening action of the above-mentioned thickening agent on the compound is great. Namely, since the initial increase in the viscosity is rapid, the time during which the compound can retain low viscosity, i.e., the time during which the compound can be impregnated into the reinforced fibers, is short after the preparation of the compound. Moreover, the above-mentioned thickening agent takes a long time to thicken the compound to a viscosity suitable for use as the SMC or BMC. Thus, the conventional molding compounds have problems that the processability in production thereof is bad, and a long time is required for the maturation thereof.
In general, molding compounds capable of being molded at low pressure have been demanded so as to reduce the molding pressure. Further, in production of such a molding compound, in order to increase the flowability, attempts to lower the viscosity of the thickened compound by reducing the amount of the thickening agent have been made. However, when the amount of the thickening agent is reduced, the surface of the resultant molding compound becomes sticky, and so-called handling characteristics in molding the molding compound are worsened. In particular, in the case of SMC, the releasability in removing a film used in production of the SMC from the surface of the SMC is worsened. On the other hand, when the amount of the thickening agent is increased, it is possible to reduce the stickiness on the surface of the resultant molding compound. In this case, although the SMC has good film releasability, the viscosity of the thickened compound becomes excessively high for low pressure molding. Therefore, when the molding compound is molded at low pressure (around 1 MPa), defects such as nonfill (unsatisfactory filling) occur due to the low flowability of the compound. It is thus impossible to produce a molding compound that is particularly suitable for low pressure molding by only adjusting the amount of the thickening agent.
Furthermore, it is known that the thickening action of the thickening agent and the viscosity of the thickened compound depend greatly on the moisture content of the compound (see, for example, "Latest Application Technique Moisture! Section, pages 72-74, Chunichisha CO. LTD., Sep. 1, 1990). More specifically, when a uniform amount of the thickening agent is used for the compound, if the moisture content of the compound is great, the initial thickening rate becomes higher. Consequently, the flowability of the compound is lowered, and poor impregnation will result. In addition, since the viscosity of the thickened compound is further lowered, the production of the molding compound becomes difficult. On the contrary, when the moisture content of the compound is small, the initial thickening rate becomes lower, and the viscosity after thickened becomes higher.
Accordingly, when producing the conventional molding compound, it is necessary to adjust the working environment, for example, adjust the humidity to reduce the moisture content of the compound as small as possible, so that the molding compound has improved processability and uniform quality. Mor
REFERENCES:
patent: 4011195 (1977-03-01), Self
patent: 4067845 (1978-01-01), Epel et al.
patent: 4192791 (1980-03-01), Self
patent: 4251576 (1981-02-01), Osborn et al.
patent: 4299927 (1981-11-01), Dombroski
patent: 4347331 (1982-08-01), Self
patent: 5212217 (1993-05-01), Yukawa et al.
patent: 5331041 (1994-07-01), Takayama et al.
patent: 5364903 (1994-11-01), Takayama et al.
patent: 5382619 (1995-01-01), Takayama et al.
"Latest Application Technique of SMC and Market View--Centering On Unsaturated Polyester", Chunichisha Co., Ltd. Sep. 1, 1990, pp. 72-74.
Hayashi Katsura
Takabatake Kouji
Utikoshi Yoshinori
Nippon Shokubai Co. , Ltd.
Reddick Judy M.
LandOfFree
Molding compound composition, molding compound containing the sa does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Molding compound composition, molding compound containing the sa, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Molding compound composition, molding compound containing the sa will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1517467