Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-10-31
2003-04-29
Mullis, Jeffrey (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S09200D, C525S09200D, C525S09200D, C525S09200D, C525S090000, C525S091000, C525S111000, C525S126000, C525S127000, C525S130000, C525S131000, C525S122000, C525S177000
Reexamination Certificate
active
06555618
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a novel compatibilizing agent for compatibilizing a radical polymerizable unsaturated resin with a polymer containing styrene as a principal component, a radical polymerizable resin composition, a molding material, and a molded article. More particularly, the present invention provides a means for solving problems of storage and molding caused by poor compatibility by improving the compatibility of the radical polymerizable resin with the polymer containing styrene as a principal component. The present invention also provides a compatibilizing agent which makes it possible to convert the resin mixture into a homogeneous resin mixture free from separation and to attain a highly value-added product.
2. Description of the Related Art
Radical polymerizable unsaturated resins are suitably used as raw resins for molding materials. However, molding materials using radical polymerizable unsaturated resin have large problems in which volume reduction, which occurs on curing, causes warpage and cracks in the molded article. For the purpose of overcoming this problem, various thermoplastic resins, for example, low profile additives such as polystyrene, styrene-butadiene rubber and the like are used. However, since these low profile additives have poor compatibility with the radical polymerizable unsaturated resin and separation after mixing is unavoidable, the resin mixture does not convert well into a homogeneous resin mixture free from separation because of its poor separation stability. Therefore, separation of the mixed low profile additive caused various molding defects such as scumming, segregation and the like.
Thus, a method of adding a stabilizer as a third component is employed and U.S. Pat. No. 3,836,600 discloses an example where a styrene-ethylene oxide block copolymer prepared by a living anionic polymerization method is used as the stabilizer. This stabilizer exerts a high compatibilizing effect and can maintain a stable dispersion state for a long period of time. However, it is difficult to industrially produce the compatibilizing agent because of its special synthesis procedure.
On the other hand, Japanese Unexamined Patent Application, First Publication No. Hei 3-174424 and Japanese Unexamined Patent Application, First Publication No. Hei 11-92646 disclose a method of improving the compatibility by introducing a vinyl acetate block or a functional group into a low profile additive. These improved low profile additives have an effect of retarding the time required to separate, but a stable dispersion state is still to be obtained by essentially improving the compatibility.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is directed to a compatibilizing agent which essentially improves the compatibility between a radical polymerizable unsaturated resin and a low profile additive containing styrene as a principal component, thereby to prevent molding defects caused by separation on molding or exhibit a stable dispersion state for a long period of time in the state of a resin mixed solution. That is, an object of the present invention is to provide a practical compatibilizing agent which makes it possible to convert the resin mixture into a homogeneous resin mixture free from separation and to eliminate defects caused by separation on molding by prevention of the separation between the radical polymerizable unsaturated resin and low profile additive, which could have not been attained by the prior art.
The present inventors have intensively studied about these objects, thus completing the present invention.
The present invention provides a compatibilizing agent for,compatibilizing a radical polymerizable unsaturated resin with a polymer containing styrene as a principal component, said compatibilizing agent being a compound (D) obtained by reacting a polymeric compound (A), a polymeric compound (B), and a compound (C), characterized in that: the polymeric compound (A) is at least one polymeric compound which is a polymer containing styrene as a principal component and has within a molecule one or more functional groups capable of reacting with the compound (C); the polymeric compound (B) is at least one polymeric compound having within a molecule one or more functional groups capable of reacting with the compound (C), which is selected from polyester, polyether, and polycarbonate; and the compound (C) is a compound which, within a molecule, has one or more functional groups capable of reacting with the functional group of the polymeric compound (A) and has one or more polyfunctional groups capable of reacting with the functional group of the polymeric compound (B). Preferably, the functional groups of the polymeric compound (A) capable of reacting with the compound (C) are one or more functional groups selected from a hydroxyl group, a carboxyl group, an epoxy group, an amino group, and a mercapto group. Preferably, the functional groups of the polymeric compound (B) capable of reacting with the compound (C) are one or more functional groups selected from a hydroxyl group, a carboxyl group, an epoxy group, an amino group, and mercapto group. Preferably, the functional groups of the compound (C) are one or more functional groups selected from an isocyanate group, a hydroxyl group, a carboxyl group, an epoxy group, and an amino group. Preferably, the compound (C) is an organopolyisocyanate compound. Preferably, at least one of the functional groups of the polymeric compound (A) is located at a molecular terminal of the compound. Preferably, the weight ratio (B)/(A) of the polymeric compound (A) and the polymeric compound (B) contained in a molecule of the compound (D) as a principal component of the compatibilizing agent is within a range of 0.2-5. Preferably, the total of the number of molecules of the polymeric compound (A) and the number of molecules of the polymeric compound (B) contained in a molecule of the compound (D) as a principal component of the compatibilizing agent is 3 or less. Preferably, the number-average molecular weight of the compound (D) as a principal component of the compatibilizing agent is within a range of 1,000 to 60,000. The present invention further provides a radical polymerizable resin composition comprising the compatibilizing agent, a radical polymerizable unsaturated resin, and a polymerizable unsaturated monomer; a molding material comprising the radical polymerizable resin composition, a polymer containing styrene as a principal component, and the compatibilizing agent; and a molded article thereof.
According to the present invention, there can be provided a practical compatibilizing agent which makes it possible to convert the resin mixture into a homogeneous resin mixture free from separation and to eliminate defects caused by separation on molding by prevention of the separation between the radical polymerizable unsaturated resin and low profile additive, which could have not been attained by the prior art, thus making it possible to obtain a molded article which is free from scumming and has excellent uniform coloring properties, surface smoothness, and surface gloss.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. The polymeric compound (A), which is a polymer containing polystyrene as a principal component and has one or more functional groups, is not limited with respect to the synthesis procedure, structure or the like, as far as it is a polymer which has one or more functional groups and contains styrene as a principle component. For example, a polystyrene compound having a functional group at terminal can be synthesized by a method such as radical polymerization using an azo initiator, and living anionic polymerization, while a polystyrene compound having within a molecule a functional group can be synthesized by copolymerizing styrene with a functional group-containing unsaturated monomer. There is also included a compound in which the styrene-conjugated diene block copolymer is
Takano Akira
Yasumura Takashi
Armstrong Westerman & Hattori, LLP
Dainippon Ink and Chemicals Inc.
Mullis Jeffrey
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