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
1988-05-05
1992-01-28
Schofer, Joseph L.
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...
524287, 524568, 524114, C08K 332
Patent
active
050845004
DESCRIPTION:
BRIEF SUMMARY
TECHNOLOGICAL FIELD
The present invention relates to a thermoformable vinylidene chloride resin composition. More particularly, the present invention relates to a vinylidene chloride resin composition in which decomposition foaming or discoloration is controlled at the forming step and which has an excellent gas permeability and is valuable as a material for the production of a packaging material. Moreover, the present invention relates to a resin laminate comprising this resin composition.
PRIOR ART
A vinylidene chloride resin has an excellent oxygen barrier property, and among various oxygen barrier resins, a vinylidene chloride resin has an extremely low water vapor permeability and the humidity dependency of the oxygen permeability of this resin is extremely small. Therefore, a vinylidene chloride resin is widely used as a gas insulating packaging material.
In the case where the vinylidene chloride resin is used in the field of packaging materials, an aqueous latex of the vinylidene chloride resin is used in the formation of a package because the vinylidene chloride resin is easily thermally decomposed. One example is where a latex of vinylidene chloride resin is coated on a finished formed body of another resin (see, for example, the specification of U.S. Pat. No. 4,370,368). Another example is where an aqueous latex of a vinylidene chloride resin is coated on a polyester preform (parison) for draw blow forming of a polyester bottle (see the specification of U.S. Pat. No. 4,393,106).
It is known that a vessel such as a bottle can be prepared by thermoforming a vinylidene chloride resin, and, for example, the specification of U.S. Pat. No. 4,041,235 teaches that a vinylidene chloride copolymer containing 0.5 to 10% by weight of glycidyl methacrylate as an internal heat stabilizer can be extruded into a parison and the parison blow formed into a bottle. Furthermore, the specification of U.S. Pat. No. 4,123,477 teaches that a film having excellent transparency and an excellent gas barrier property is prepared by the inflation film-forming process from a resin composition comprising 100 parts by weight of a copolymer comprising 75 to 95% by weight of vinylidene chloride and 5 to 25% by weight of a comonomer and 3 to 60 parts by weight of a chlorinated ethylene/vinyl ester copolymer.
Use of a vinylidene chloride resin in the form of an aqueous latex for the production of a packaging material is not advantageous from the economical viewpoint, because troublesome operations such as coating and drying are necessary and a large quantity of heat energy is necessary for evaporation and removal of water.
A resin composition formed by incorporating a low molecular weight or high molecular weight lubricant at a high concentration into a vinylidene chloride resin can resist thermoforming conducted at a relatively low temperature such as 170.degree. to 180.degree. C., but at extrusion molding or injection molding conducted at higher temperatures, foaming or discoloration is caused by a dehydrohalogenating thermal decomposition, and the inherent gas barrier property thereof is lost.
In the case where a multi-layer laminate formed by combining a vinylidene chloride resin as a gas barrier layer with other resin is used as a packaging material, simultaneous melt extrusion molding of the vinylidene chloride resin with another resin, or co-injection molding or sequential injection of the vinylidene chloride resin with another resin, becomes necessary. Accordingly, the vinylidene chloride resin layer is exposed to the high temperature possessed by the other resin, and, therefore, the above mentioned problems such as foaming, discoloration and a reduction of mechanical properties are encountered.
Incorporation of a large quantity of a plasticizer for imparting a low temperature thermoformability capability to a vinylidene chloride resin is not preferred, because the gas barrier property of the final packaging material is degraded and, especially, the gas barrier property of the final packaging material after retort steri
REFERENCES:
patent: 3513226 (1970-05-01), Hotta
patent: 4127633 (1978-11-01), Addleman
patent: 4132691 (1979-01-01), Ejk
S. Krimm and C. Y. Liang, J. of Polymer Science, vol. XXII, pp. 95-112 (1956).
Ronald H. Faster, Polymers, Laminations and Coating Conference, pp. 437-461 (1984).
Kano Fumio
Yamada Muneki
Mulcahy Peter
Schofer Joseph L.
Toyo Seikan Kaisha Ltd.
LandOfFree
Thermoformable vinylidene chloride resin composition and resin l does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermoformable vinylidene chloride resin composition and resin l, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoformable vinylidene chloride resin composition and resin l will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1861366