Composition and method for extruding plastic articles having accent color pattern
First Claim
1. A method of producing a capstock having a controllable and realistic wood-grain appearance, the capstock with at least one accent color, the method comprising the steps of:
- a) introducing into an extruder a capstock base material and accent color pellets, said capstock base material having a vicat softening temperature, said accent color pellets (i) having a higher vicat softening temperature than said capstock base material, and (ii) comprising poly-α
-methylstyrene having a high vicat softening temperature and a melt flow index of greater than or equal to 1.0 gram per 10 minutes, and at least one additional resin having a substantially lower vicat softening temperature than the poly-α
-methlstyrene; and
b) extruding said capstock base material and said accent color pellets through an extrusion die to form a capstock under processing temperatures whereby the accent color pellets cause delayed introduction and controlled dispersion of the accent color into the capstock base material.
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Accused Products
Abstract
A new and useful a plastic article, particularly plastic siding, with an accent color pattern incorporated therein, a specially formed accent color pellet which is useful in manufacturing such an article, and a process for producing the article using the pellets are provided. The process contemplates extruding a plastic product from a base material formed of powder-sized particles and specially formed accent color pellets. The accent color pellets are alloyed masses of resins and pigment which are larger than the powder particles of the base material, and have a higher vicat softening point temperature than the base material. The alloyed pellets are designed to melt controllably and to mix controllably with the base material. During the extrusion process, the accent color pellets begin to soften and disperse later than the base material, and cause controllable dispersion of the accent color into the base material, thereby producing accent color streaks in the resulting product having controllable characteristics. The process is particularly suited for producing a simulated wood-grain or streaking effect in plastic siding, and as described can produce hard streaking, soft streaking, and a mottled or variegated streaking in which more than one accent color is used simultaneously. A novel formulation for the accent color pellets is disclosed, in which poly-α-methylstyrene is used as the only high vicat softening temperature resin.
83 Citations
20 Claims
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1. A method of producing a capstock having a controllable and realistic wood-grain appearance, the capstock with at least one accent color, the method comprising the steps of:
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a) introducing into an extruder a capstock base material and accent color pellets, said capstock base material having a vicat softening temperature, said accent color pellets (i) having a higher vicat softening temperature than said capstock base material, and (ii) comprising poly-α
-methylstyrene having a high vicat softening temperature and a melt flow index of greater than or equal to 1.0 gram per 10 minutes, and at least one additional resin having a substantially lower vicat softening temperature than the poly-α
-methlstyrene; andb) extruding said capstock base material and said accent color pellets through an extrusion die to form a capstock under processing temperatures whereby the accent color pellets cause delayed introduction and controlled dispersion of the accent color into the capstock base material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of producing a capstock having a controllable and realistic wood-grain appearance, the capstock with at least one accent color, the method comprising the steps of:
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a) introducing into an extruder a capstock base material and accent color pellets, said capstock base material having a vicat softening temperature, said accent color pellets having a vicat softening temperature that is about 15°
C. to about 50°
C. higher than the vicat softening temperature of said base material, said accent color pellets comprising (i) about 10% to about 30% by weight poly-α
-methylstyrene, (ii) about 30% to about 50% by weight of at least one additional resin having a substantially lower vicat softening temperature than the poly-α
-methylstyrene, and (iii) about 30% to about 45% by weight of a color pigment; andb) extruding said capstock base material and said accent color pellets through an extrusion die to form a capstock under processing temperatures whereby the accent color pellets cause delayed introduction and controlled dispersion of the accent color into the capstock base material. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification