PARTING AGENT

Abstract: A water-base parting agent mainly comprising a halogenated polyether having at least one functional group, which is free from the problem of environmental pollution, is excellent in dispersibility, storage stability and mold release performance, and imparts a good surface state to polymer moldings.

Description: SPECIFICATION FIELD OF THE INVENTION The present invention relates to a mold release agent. Particularly, it relates to a water-based mold release agent used for the preparation of a shaped article of a polymeric material such as a synthetic resin and a rubber. RELATED ART AND PROBLEMS Hitherto, an organic solvent-based mold release agent comprising a halogen-containing polyether as a main component is known (cf. Japanese Patent Kokai Publication No. 112610/1986). Although the mold release agent comprising the halogen-containing polyether has good mold releasability, it has the problem that the environment is polluted during the use of it since it contains the organic solvent. It is required to develop a water-based mold release agent comprising a halogen-containing polyether as the main component; which is free from the environmental pollution. The water-based mold release agent comprising the halogen-containing polyether as the main component which is disclosed in Japanese Patent Kokai Publication No. 112610/1986 has the problem that the mold release agent has poor storage stability (namely, the halogen-containing polyether is separated from the mold release agent). SUMMARY OF THE INVENTION An object of the present invention is to provide a water-based mold release agent which is free from the environmental pollution problem during its use, which has excellent dispersibility, storage stability and mold releasability and which gives a good surface state to a molded article of a polymeric material. The present invention provides the use of a composition comprising a perfluoropolyether having at least one functional group which is neither halogen nor an ether group, another surfactant, and water, as a water-based mold release agent. The perfluoropolyether used in the present invention has at least one functional group, and the halogen-containing polyether having no functional group which is described in Japanese Patent Kokai Publication No. 112610/1986 is not preferable in the present invention. The halogen-containing perfluoropolyether having at least one functional group may be well-known one and is described in Japanese Patent Kokai Publication No. 131132/1989 (corresponding to US Patent No. 4,836,944), Japanese Patent Kokai Publication No. 134189/1991, Japanese Patent Kokai Publication No. 268664/1989 (corresponding to US Patent No. 5,004,544), and Japanese Patent Kokai Publication No. 132917/1991. Specific examples of preferable perfluoropolyethers are wherein R is ―CH 2 OH, or m is 1 to 50, n is 1 to 100, p is 0 to 100, q is 0 to 100 and r is 1 to 50. A perfluoropolyether having a carboxylic acid group or salt thereof is preferable in view of the adherence to a mold surface. The halogen-containing polyether preferably has an average molecular weight of 1,000 to 5,000, more preferably 1,500 to 3,500. The surfactant (G) may be any of a hydrocarbon surfactant and a fluorine-containing surfactant. Specific examples of the surfactant are Rapizol B-80 (manufactured by Nippon Oil and Fats Co., Ltd.), Nonion NS 230 (manufactured by Nippon Oil and Fats Co., Ltd.), Nonion NS 220 (manufactured by Nippon Oil and Fats Co., Ltd.), Unidine DS 403 (Daikin Industries Ltd.). Among them, the nonionic surfactant is preferable in view of the storage stability. When a nonionic hydrocarbon surfactant is used, the mold release agent is transparent (no cloudiness) and has remarkably excellent storage stability. The water-based mold release agent used in the present invention can be prepared, for example, by emulsifying the perfluoro polyether, the surfactant and water by an ultrasonic homogenizer. The water-based mold release agent used in the present invention may further contains d) a phosphate ester or a salt thereof having a pefluoroalkyl group having 4 to 20 carbon atoms. Specific examples of the perfluoroalkyl group-containing phosphate ester are wherein m is 1 to 9, n is 1, 2 or 3. In view of the stability, it is preferable that the perfluoro polyether is emulsified in water and then the perfluoroalkyl group-containing phosphate ester is added to the emulsion. The phosphate ester having the perfluoroalkyl group having 4 to 20 carbon atoms gives, for example, excellent releasability for a urethane. The water-based mold release agent used in the present invention may contain a silicone or wax compound. The silicone or wax compound improves the surface state of the shaped article so as to reduce a cell collapse, particularly in the case of the polyurethane foam which tends to have the cell collapse. Specific examples of the silicone compound are a silicone oil, a silicone resin, a mixture of silicone oil and resin. Specific example of the wax compound is a paraffinic wax. The water-based mold release agent used in the present invention preferably comprises a) 1 part by weight of the perfluoro polyether. b) 0.02 to 0.8 parts by weight, preferably 0.1 to 0.5 parts by weight of the surfactant, and d) 0 to 1.0 parts by weight, preferably 0.1 to 0.8 parts by weight, more preferably 0.2 to 0.3 parts by weight of the perfluoroalkyl group-containing phosphate ester or salt thereof. The amount of silicone or wax compound is from 0 to 5.0 parts by weight, preferably from 0 to 1.0 parts by weight per 1 part by weight of the halogen-containing polyether. The water-based mold release agent used in the present invention may contain usually 0.1 to 20 % by weight, preferably 0.5 to 10 % by weight of the components other than water c). The mold release agent can be used in a low concentration, migrates to the shaped article in a very low amount, and gives an easy post-treatment (good coating property and adhesion property). The mold release agent used in the present invention can be used as an internal mold release agent, but it is preferably used as an external mold release agent. When the mold release agent is coated on a mold, any of a brush coating method, a dip coating method, a spray coating method and the like can be used. The mold release agent is useful for the preparation of the shaped article made of a synthetic resin and a rubber, particularly a polyurethane or a polyurea. PREFERRED EMBODIMENT OF THE INVENTION The present invention will be illustrated by the following Examples and Comparative Examples. Examples 1 to 11 and Comparative Examples 1 to 4 A mold release agent was prepared by emulsifying the components shown in Table 1 at 25°C for 6 minutes by the use of an ultrasonic homogenizer (manufactured by Choonpakogyo Co. Ltd., Output: 300 W). Then, the mold release agent was coated on a mold, and a urethane foam was molded from a liquid A and a liquid B shown in Table 2. The mold releasability and the surface state of the shaped article were evaluated. A mold release stress (g/cm 2 ) was measured by the use of an autographic device (manufactured by Shimadzu Corp., DCM-50M). The results are shown in Table 3. Table 3 also show stability of the mold release agent. Sannix FA-912 Polyol 100 pbw manufactured by Sanyo Chemical Industries Ltd. Liquid A Ethylene glycol Cross-linking agent 9 pbw (ditto) Flon 11U Foaming agent 15 pbw (ditto) DABCO 33LV Catalyst 4 pbw (ditto) Liquid B Colonate 1040 Isocyanate 65 pbw manufactured by Nippon Polyurethane Ltd. Molding conditions: Mold material aluminum Mold size 5.5 cm diameter x 1.0 cm Stirring time 5,000 rpm x 10 seconds Foaming and curing time 10 minutes Mold temperature 40°C Method of coating the mold release agent brush-coating at room temperature Example No. Stability Mold releasability (g/cm 2 ) Surface state 1 Good 160 Good 2 Good 170 Good 3 Good 95 Good 4 Very good 110 Good 5 Very good 125 Good 6 Very good 150 Good 7 Good 150 Good 8 Good 230 Good 9 Good 100 Good 10 Good 150 Good 11 Good 160 Good Com. 1 Bad 190 Good Com. 2 Very good 230 Pinholes formed Com. 3 Very good 300 Good Com. 4 Very good 350 Good Note) Stability: Very Good: Transparent (not separated after two weeks) Good: Milky white (separated after one week) Bad: Milky white (separated after two days) Surface state: Good: No cell collapse EFFECTS OF THE INVENTION The water-based mold release agent used in the present invention gives no environmental pollution, has excellent dispersibility, storage stability and mold releasability and gives a good surface state to the shaped article of the polymeric material. In addition, the water-based mold release agent used in the present invention forms a reversed micelle having the functional group present in water. The water-based mold release agent used in the present invention is adsorbed easily and selectively by the mold surface and can form a tough coating film having good durability. The water-based mold release agent used in the present invention can give more uniform thickness of a coating film than an organic solvent based mold release agent.

Claims: Use of a composition comprising: a) a perfluoropolyether having at least one functional group which is neither halogen nor an ether group, b) another surfactant, and c) water, as a water-based mold release agent. The use according to claim 1, which further contains d) a phosphate ester or salt thereof having a perfluoroalkyl group having 4 to 20 carbon atoms. The use according to claim 1 or claim 2, wherein the surfactant (b) is a nonionic surfactant. The use according to any preceding claim, wherein the functional group is a carboxylic acid group or salt thereof.

Inventors: FUJIWARA SHINGO, YAMAMOTO IKUO, YAMANA MASAYUKI, FUJIWARA, SHINGO, YAMAMOTO, IKUO, YAMANA, MASAYUKI, FUJIWARA, SHINGO, YODOGAWA WORKS OF, YAMAMOTO, IKUO, YODOGAWA WORKS OF, YAMANA, MASAYUKI, YODOGAWA WORKS OF
Applicants: DAIKIN IND LTD, DAIKIN INDUSTRIES, LTD.
Application year: 1993
Main classification: C08G65
IPC codes: B29C33, C08K5, C10M173, C08L71, C10N40, C10N30, B29K71