Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-12-31
2001-02-20
Boykin, Terressa M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C528S176000, C528S196000
Reexamination Certificate
active
06191198
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Technical Field
The present invention relates to: a micro-powdery stain composition for an unsaturated polyester resin; an unsaturated polyester resin composition; and a production process for the unsaturated polyester resin composition.
B. Background Art
Generally, molding processes of FRP are, for example, as follows: a process comprising the step of press-molding a molding material such as SMC (Sheet Molding Compound) or BMC (Bulk Molding Compound) as obtained by molding an unsaturated polyester resin composition into a sheet or bulky shape respectively, wherein the unsaturated polyester resin composition is prepared by combining an unsaturated polyester resin with a low-shrinkage agent, a filler, a stain, a glass fiber and so on; and a hand-lay-up-molding process comprising the step of coating a stain resin, which is called gel coat, to a mold by spray- or hair-coating, and then reinforcing the coated matter with a glass fiber or unsaturated polyester resin. The stain, used in these molding processes, is a pasty stain which is obtained by kneading an unsaturated polyester resin, a plasticizer, and either or both of a pigment and an oil-soluble dye using a three-roll mill, a bead mill, or the like.
The unsaturated polyester resin is usually a solution in which a liquid polymerizable monomer such as a styrene monomer is used as the solvent, so there is a merit in that the pasty stain is easy to disperse because liquids easily disperse into each other, but there are various problems in that the gelation or the increase of the viscosity occurs when conserving the stain, and the usage therefore becomes impossible, and in that color differences or color separations occur due to sinking of substances of heavy specific gravity such as titanium oxide.
SUMMARY OF THE INVENTION
A. Object of the Invention
It is an object of the present invention to provide: a stain composition for an unsaturated polyester resin, and an unsaturated polyester resin composition, both of which have excellent conservation stability without the above problems that might occur when conserving the stain; and further a production process for the unsaturated polyester resin composition.
B. Disclosure of the Invention
The present inventors studied with encouragement to themselves and great efforts to solve the above problems. As a result, they found that if a micro-powdery composition, comprising either or both of a pigment and an oil-soluble dye as well as at least one resin selected from the group consisting of polystyrene, low molecular polystyrene, low molecular acrylstyrene and low molecular acryl, is used as the stain composition, a stain composition for an unsaturated polyester resin is obtained, which composition for an unsaturated polyester resin has excellent conservation stability without the above demerits on the pasty stain, that is to say, the gelation, the viscosity increase, the sinking, the color separation, and so on. Also, the inventors found that for obtaining the dispersibility of the above stain composition into the unsaturated polyester resin at not lower than the same level as of the pasty stain, it is desirable to adjust the particle diameter of the above stain composition to fall in the specific range. Thus, the inventors achieved the present invention.
That is to say, the present invention has the below constitution.
(1) A micro-powdery stain composition for an unsaturated polyester resin, comprising either or both of a pigment and an oil-soluble dye as well as a resin,
characterized in that the resin as included in the composition is at least one resin selected from the group consisting of polystyrene, low molecular polystyrene, low molecular acrylstyrene and low molecular acryl.
(2) A micro-powdery stain composition for an unsaturated polyester resin as described in (1) above, which has an average particle diameter of 900 micron or less.
(3) An unsaturated polyester resin composition, comprising an unsaturated polyester resin and either or both of a pigment and an oil- soluble dye,
with the composition being characterized by further comprising at least one resin selected from the group consisting of low molecular polystyrene, low molecular acrylstyrene and low molecular acryl.
(4) A production process of an unsaturated polyester resin composition including an unsaturated polyester resin and either or both of a pigment and an oil-soluble dye,
with the process being characterized by comprising the step of mixing the unsaturated polyester resin with a micro-powdery stain composition which includes either or both of a pigment and an oil-soluble dye as well as at least one resin selected from the group consisting of polystyrene, low molecular polystyrene, low molecular acrylstyrene and low molecular acryl.
These and other objects and the advantages of the present invention will be more fully apparent from the following detailed disclosure.
DETAILED DESCRIPTION OF THE INVENTION
Either or both of the pigment and the oil-soluble dye, used in the present invention, are not limited providing that they do not involve the discoloration or the deterioration of the physical properties of the resin when coloring the unsaturated polyester resin. Examples of the pigment include: organic pigments of the types such as monoazo, disazo, polyazo, phthalocyanine, quinacridone, perylene, perinone, and their heterocyclic ones; and inorganic pigments, such as carbon black, titanium oxide, titanium yellow, cobalt green, cobalt blue, ultramarine, red iron oxide, barium sulfate and sintered pigments. Examples of the oil-soluble dye include the types such as monoazo, disazo, anthraquinone, perylene, perinone, and their heterocyclic ones.
The respective molecular weights of the low molecular polystyrene, the low molecular acrylstyrene and the low molecular acryl, used in the present invention, are preferably in the range of 1,000~10,000 and more preferably in the range of 1,500~5,000 in terms of number-average molecular weight. Because these resins have low molecular weight, these resin have excellent solubility in the unsaturated polyester resin composition, and further, it is not necessary to use a special device as a processing machine.
The molecular weight of the polystyrene, used in the present invention, is usually in the range of 60,000~200,000 and preferably in the range of 80,000~100,000 in terms of number-average molecular weight. Thus, the molecular weight of the polystyrene is distinguished from that of the low molecular polystyrene. When using the polystyrene, it is preferable to use together a plasticizer to improve the processability and the solubility. Examples of such a plasticizer include dioctyl phthalate, dibutyl phthalate and diallyl phthalate.
The polystyrene, the acrylstyrene and the acryl have merits in that they have solubility to a styrene monomer which is used to dissolve the unsaturated polyester resin and in that they further serve as a low-shrinkage agent in the SMC usage and so on.
The mixing ratio of either or both of the pigment and the oil-soluble dye to the at least one resin selected from the group consisting of polystyrene, low molecular polystyrene, low molecular acrylstyrene and low molecular acryl is not especially limited. A production process, for example, can be used, which process comprises the following sequential steps of: mixing all components beforehand; kneading the resultant mixture in a heat-melted state with a kneading machine such as a three-roll mill, a kneader, a Banbury mixer or a twin-screw extruder; cooling the mixture to normal temperature; and pulverizing the mixture with a conventional pulverizing machine, for example, a hammer mill as equipped with a screen of the diameter of 1 mm.
A preferable mixing ratio in the micro-powdery stain composition of the present invention is such that the at least one resin selected from the group consisting of polystyrene, low molecular polystyrene, low molecular acrylstyrene and low molecular acryl is in the range of 80~500 weight parts per 100 weight parts of either or both of the pigmen
Hamahira Eizo
Nakayama Takasi
Boykin Terressa M.
Sumika Color Company, Limited
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