Browse Prior Art Database

BETA NUCLEATOR FOR POLYPROPYLENE

IP.com Disclosure Number: IPCOM000030969D
Publication Date: 2004-Sep-02
Document File: 2 page(s) / 18K

Publishing Venue

The IP.com Prior Art Database

Abstract

Isotactic polypropylene is known to exist in several different crystal phases. The most common of these phases is the alpha phase. However, under certain conditions another crystal phase, the beta phase, can occur. This invention relates to the use of zinc adipate as an additive that can cause polypropylene to preferentially form the beta phase. In this invention, zinc adipate is melt homogenized with polypropylene. When the polypropylene is then cast or molded, a large fraction of the polymer will form the beta phase, which has a different melting point than the more usual alpha phase. Products with beta crystallinity can exhibit much higher impact resistance than those with alpha crystallinity. They can also be used to produce micro-porous films.

This text was extracted from a Microsoft Word document.
This is the abbreviated version, containing approximately 64% of the total text.

Beta Nucleator for Polypropylene

Isotactic polypropylene is known to exist in several different crystal phases.  The most common of these phases is the alpha (a) phase.  However, under certain conditions another crystal phase, the beta (b) phase, can occur.  This invention relates to the use of zinc adipate as an additive that can cause polypropylene to preferentially form the beta phase.  In this invention, zinc adipate is melt homogenized with polypropylene.  When the polypropylene is then cast or molded, a large fraction of the polymer will form the beta phase, which has a different melting point than the more usual alpha phase.  Products with beta crystallinity can exhibit much higher impact resistance than those with alpha crystallinity.  They can also be used to produce micro-porous films.

Additive Preparation:

1.        All carboxylic acids were dried overnight using activated sieves under nitrogen.

2.        Calcium hydride (0.694 grams) was mixed with equimolar amounts of adipic acid.  The reactants were mixed with 75 ml of THF at room temperature, and stirred.  The solvent was evaporated, and 2.69 grams of grayish solid (calcium adipate) was recovered.

3.        Calcium hydride (0.738 grams) was mixed with an equimolar amount of terephthalic acid.  The reactants were mixed with 75 ml of THF at room temperature, and stirred.  The slurry was filtered and rinsed with THF, which was followed by drying in a vacuum.  About 4.04 grams of a grayish solid (calcium terephthalate) was recovered.

4.        Diethyl zinc (1.5 grams) was dissolved in 100 ml of THF.  Two grams of terephthalic acid was slowly added to the solution at room temperature while it was being stirred.  The slurry was filtered and rinsed and the resultant zinc terephthalate was then dried.  About 3.59 grams was recovered.

5.        Diethyl zinc (1.9 grams) was dissolved in 100 ml of THF.  1.9 grams of adipic acid were slowly added to the solution at room temperature while it was being stirred.  The slurry was filtered and rinsed and the resultant zinc terephthalate was then dried.  About 2.76 grams was recovered.

Polymer Preparation:

Polypropylene homopolymer powders were dry blended with the additives described in the tables below.  The mixtures were then extruded on a ¾ inch Brabender extruder, utilizing a mixing screw.  The amount of beta crystallinity was determined by using a DSC under the following protocol.  The sample was held for 0.2 minutes at 0 °C.  It was then heated to 220 °C at 10 °C /minute, followed by cooling to 0 °C at 10 °C /minute.  After being held at 0 °C for 5 minutes, the sample was reheated at 10 °C /minute up to a temperature of 220 °C.  Using an enthalpy of melting for alpha crystals of 178 J/gram and an enthalpy of melting of 170 J/gram for beta crystals, the percentage of the total crystallinity that was in beta form was then determined from the second heat.

SAMPLE A B C D E F

Irganox 1010, ppm 1000 1000 1000 1000 1000 1000

Irgafos 168, ppm 1000 1...