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
2001-03-20
2003-07-01
Short, Patricia A. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S165000
Reexamination Certificate
active
06586527
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to nucleated polyester resin and blends thereof.
2. Background of the Invention
The overall crystallization rate of polyesters can be enhanced by several nucleating additives, such as minerals, salts, pigments, etc. Such heterogeneous nucleating agents may however adversely affect mechanical properties and/or polyester stability. U.S. Pat. No. 3,833,535 to Wambach et al, describe the addition of nucleating agents polyesters in column 7, lines 37 to 52. U.S. Pat. No. 5,344,892 to Kavilipalayam et al describes the addition of an alkali metal salt of a polyphenylene ether as a nucleating agent.
It is desirable to obtain enhanced properties for improving the processing and crystallinity of cycloaliphatic resin compositions while retaining the favorable properties. When considering mixtures, blends, and additives to resin blends, it is difficult to obtain an improvement of one property without deleteriously affecting other desirable properties.
SUMMARY OF THE INVENTION
The present invention relates to molding compositions based upon thermoplastic cycloaliphatic polyester resin and blend thereof, which have desirable properties of impact resistance and good processability. The crystallinity and rate of crystallization are desirable improved as compared to known cycloaliphatic polyester compositions.
The polyester molding compositions of the present invention comprise a cycloaliphatic polyester component, and a nucleating agent comprising a fluoropolymer containing thermoplastic resin. The fluoropolymer containing thermoplastic resin is desirably in the form of a free-flowing powder. According to one embodiment, a process for accelerating the crystallization of a resin blend containing a cycloaliphatic polyester component comprises preparing a mixture of the resin components and a fluoropolymer thermoplastic nucleating agent. Also, a shaped article is prepared by shaping a heated plasticized blend which includes the fluoropolymer thermoplastic nucleating agent and cooling the shaped plasticized blend to form a solidified shaped article.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The nucleating agent is a fluoropolymer-containing thermoplastic resin composition and is prepared by combining a fluoropolymer with a thermoplastic resin according to U.S. Pat. No. 6,040,370 to Wozne et al and U.S. Pat. No. 5,804,654 to Lo et al.
As set forth in U.S. Pat. No. 5,804,654, the tetrafluoroethylene polymerizate comprises particles totally or partially encapsulated by a polymer or copolymer obtained by polymerization of monomers or mixtures of monomers which can be emulsion-polymerized, in particular by radical route. Column 3, line1 to column 3, line 45 is incorporated into the present application by reference. The resulting fluoropolymer particles are useful as a nucleating agent.
As set forth in U.S. Pat. No. 6,040,370, a fluoropolymer-containing additive is prepared by combing a fluoropolymer in the form of a stabilized aqueous fluoropolymer dispersion including a second polymer with a fatty acid salt. The combined fluoropolymer and second polymer are precipitated. The resulting precipitate is dried to form the fluoropolymer additive. Column 2, line 55 to column 8, line 53, is incorporated into the present specification by reference. The resulting additive is useful as the nucleating agent for the present invention.
Suitable fluoropolymers include homopolymers and copolymers that comprise repeating units derived from one or more fluorinated &agr;-olefin monomers. The term “fluorinated &agr;-olefin monomer” means an &agr;-olefin monomer that includes at least one fluorine atom substituent. Suitable fluorinated &agr;-olefin homopolymers include e.g., poly(tetra-fluoroethylene), poly(hexafluorethylene).
The second polymer preferably contains repeating units derived from styrene and acrylonitrile. More preferably, the second polymer comprises from 60 to 90 wt % repeating units derived from styrene and 10 to 40 wt % repeating units derived from acylonitrile.
In a preferred embodiment, the particle size of the polymerized fluoropolymer nucleating agent is in the range of 20 to 1000 micron, more preferably from 50 to 800 micron.
The cycloaliphatic polyester resin comprises a polyester having repeating units of the formula I:
where at least one R or R1 is a cycloalkyl containing radical.
The polyester is a condensation product where R is the residue of an aryl, alkane or cycloalkane containing diol having 6 to 20 carbon atoms or chemical equivalent thereof, and R1 is the decarboxylated residue derived from an aryl, aliphatic or cycloalkane containing diacid of 6 to 20 carbon atoms or chemical equivalent thereof with the proviso that at least one R or R1 is cycloaliphatic. Preferred polyesters of the invention will have both R and R1 cycloaliphatic.
The present cycloaliphatic polyesters are condensation products of aliphatic diacids, or chemical equivalents and aliphatic diols, or chemical equivalents. The present cycloaliphatic polyesters may be formed from mixtures of aliphatic diacids and aliphatic diols but must contain at least 50 mole % of cyclic diacid and/or cyclic diol components, the remainder, if any, being linear aliphatic diacids and/or diols. The cyclic components are necessary to impart good rigidity to the polyester.
The polyester resins are typically obtained through the condensation or ester interchange polymerization of the diol or diol equivalent component with the diacid or diacid chemical equivalent component.
R and R1 are preferably cycloalkyl radicals independently selected from the following formula:
The preferred cycloaliphatic radical R1 is derived from the 1,4-cyclohexyl diacids and most preferably greater than 70 mole % thereof in the form of the trans isomer. The preferred cycloaliphatic radical R is derived from the 1,4-cyclohexyl primary diols such as 1,4-cyclohexyl dimethanol, most preferably more than 70 mole % thereof in the form of the trans isomer.
Other diols useful in the preparation of the polyester resins of the present invention are straight chain, branched, or cycloaliphatic alkane diols and may contain from 2 to 12 carbon atoms. Examples of such diols include but are not limited to ethylene glycol; propylene glycol, i.e., 1,2- and 1,3-propylene glycol; 2,2-dimethyl-1,3-propane diol; 2-ethyl, 2-methyl, 1,3-propane diol; 1,3- and 1,5-pentane diol; dipropylene glycol; 2-methyl-1,5-pentane diol; 1,6-hexane diol; dimethanol decalin, dimethanol bicyclo octane; 1,4-cyclohexane dimethanol and particularly its cis- and trans-isomers; triethylene glycol; 1,10-decane diol; and mixtures of any of the foregoing. Preferably a cycloaliphatic diol or chemical equivalent thereof and particularly 1,4-cyclohexane dimethanol or its chemical equivalents are used as the diol component.
Chemical equivalents to the diols include esters, such as dialkylesters, diaryl esters and the like.
The diacids useful in the preparation of the aliphatic polyester resins of the present invention preferably are cycloaliphatic diacids. This is meant to include carboxylic acids having two carboxyl groups each of which is attached to a saturated carbon. Preferred diacids are cyclo or bicyclo aliphatic acids, for example, decahydro naphthalene dicarboxylic acids, norbornene dicarboxylic acids, bicyclo octane dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid or chemical equivalents, and most preferred is trans-1,4-cyclohexanedicarboxylic acid or chemical equivalent. Linear dicarboxylic acids like adipic acid, azelaic acid, dicarboxyl dodecanoic acid and succinic acid may also be useful.
Cyclohexane dicarboxylic acids and their chemical equivalents can be prepared, for example, by the hydrogenation of cycloaromatic diacids and corresponding derivatives such as isophthalic acid, terephthalic acid or naphthalenic acid in a suitable solvent such as water or acetic acid using a suitable catalysts such as rhodium supported on a carrier such as carbon or alumina. See, Friefelder et al., Journal of Organic Chemistry, 31, 3438
den Breejen Aagje Petronella
Hieltjes Gerardus Bernardus Wilhelmus
Mercx Franciscus Petrus Maria
Vollenberg Peter Hendrikus Theodurus
Oppedahl & Larson LLP
Short Patricia A.
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