Plastic and nonmetallic article shaping or treating: processes – With printing or coating of workpiece – Anti-stick or adhesion preventing coating
Patent
1996-05-15
2000-06-13
Moore, Margaret G.
Plastic and nonmetallic article shaping or treating: processes
With printing or coating of workpiece
Anti-stick or adhesion preventing coating
264213, 264264, 264300, 264338, 525104, 528 34, 528 29, B29C 4102
Patent
active
060745886
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a mold releasing agent, a cured film obtained therefrom and a method of molding using such a mold releasing agent, and specifically relates to a mold releasing agent, a cured film and a molding method, which are used when producing molded articles of high molecular compounds such as synthetic resins and rubbers.
BACKGROUND ART
In order to obtain molded articles from resins or rubbers, molding is carried out after a die is filled with resin or rubber materials, and usually the inner surface of the die is previously coated with a mold releasing agent before filling.
As the mold releasing agent, there are waxes such as a paraffin wax and a polyethylene wax, silicones such as a polydimethylsiloxane oil and a silicone resin, organic compounds such as a glycol, a derivative of fatty acid and a perfluoroalkyl group-containing compound, and inorganic compounds such as mineral oil, talc and mica, which are used in the form of dispersion or solution in water or an organic solvent.
The above-mentioned mold releasing agents are usually applied every time of the filling. It is desired that a mold releasing agent having a lengthy life is developed to decrease the number of steps of production process from the viewpoint of workability. Also since the mold releasing agent is applied every time of the filling, there occurs a problem of contamination of a die due to deposition of the mold releasing agent, and a degree of contamination is large particularly in case of the wax type mold releasing agent. Further the reason why the coating is necessary every time of the filling is that basically there is transfer of the mold releasing agent to the molded article, which causes poor finishing such as stickiness of the molded article and coating failure and adhesion failure on the molded article in the succeeding steps. Therefore the molded articles are rinsed with an organic solvent such as trichloroethane after molding. Particularly the silicone type mold releasing agent is apt to cause the coating failure and adhesion failure.
Also in case of making molded articles of polyurethane foam, there is a drawback such that cells on surface become rough at the time of molding. This is observed remarkably particularly in case of using the silicone oil as the mold releasing agent.
Various mold releasing agents have been developed to eliminate the above-mentioned drawbacks. Examples are a mixture of phosphate having a perfluoroalkyl group of 4 to 20 carbon atoms or its salt with a silicone oil (JP-B-23270/1978 and JP-B-23271/1978), a mixture of phosphate having a perfluoroalkyl group of 4 to 20 carbon atoms or its salt with a silicone varnish (JP-B-48035/1982), a mixture of a perfluoroalkyl group-containing polyether compound with a silicone oil (JP-B-32513/1984) and the like. Those mold releasing agents are preferable and excellent in mold releasing property and have a life longer than that of conventional ones. Further the mold releasing agent prepared by using the mixture of the perfluoroalkyl group-containing polyether compound and the silicone oil has almost no effect on secondary processability with respect to most of high molecular compounds. However even those mold releasing agents cannot satisfy the mold releasing property and life which have been required in view of the high molecular compound molded articles having complicated shape and large size.
As a mold releasing agent of cured film forming type having a longer life, JP-B-39804/1991 discloses a mold releasing agent containing a ladder polymer of a perfluoroalkyl group-containing acrylic polymer and organosilsesquioxane. That mold releasing agent is excellent in initial mold releasing property and its life is made longer to a certain extent. However since strength of the cured film is not sufficient, a desired life cannot be obtained.
Also JP-B-11605/1991 discloses a mold releasing agent containing polydimethylsiloxane, an alkoxysilane represented by the formula: monovalent hydrocarbon group having 1 to 4 carbon atoms or
REFERENCES:
patent: 3189576 (1965-06-01), Sweet
patent: 3419516 (1968-12-01), Taruo
patent: 3624190 (1971-11-01), Cekada et al.
patent: 3628996 (1971-12-01), Weber
patent: 3742004 (1973-06-01), Nitzche et al.
patent: 3758441 (1973-09-01), Nitzche et al.
patent: 3941856 (1976-03-01), Creasey et al.
patent: 4018734 (1977-04-01), Dumouiin
patent: 4308212 (1981-12-01), Takamizawa et al.
patent: 4534928 (1985-08-01), Martin
patent: 4720530 (1988-01-01), Wurminghausen
patent: 4889770 (1989-12-01), Ona et al.
patent: 5079299 (1992-01-01), Hisamoto et al.
patent: 5152950 (1992-10-01), Ona et al.
patent: 5804674 (1998-09-01), Yamana et al.
Hosomi Tomohiro
Kashiwagi Masato
Sakashita Hirotoshi
Yamana Masayuki
Daikin Industries Ltd.
Moore Margaret G.
LandOfFree
Mold releasing agent, cured film obtained therefrom and molding does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mold releasing agent, cured film obtained therefrom and molding , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mold releasing agent, cured film obtained therefrom and molding will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2065970