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Compositions based on expandable vinylaromatic polymers with an improved expandability

A vinylaromatic, polymer-based technology for other chemical processes, chemical instruments and methods that can address issues such as compromising the processability and mechanical properties of the final product

Inactive Publication Date: 2008-08-06
POLIMERI EUROPA SPA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] It has been proven that the reduction of polymer molecular weight to values ​​below 50,000 also implies excellent expandability, but at the expense of processability and mechanical properties of the final product

Method used

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  • Compositions based on expandable vinylaromatic polymers with an improved expandability

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] 98 parts of polystyrene pellets with MFI (measured at 200°C / 5 kg) of 25 g / 10 minutes and Mw of 130,000 and 2 parts of polyphenylene ether (weight-average molecular weight of 262,000) were fed into the extruder through a hopper, and at the same time 500 ppm of polyethylene wax was used as nucleating agent.

[0050] A 6.5% mixture of n-pentane / isopentane 80 / 20 was fed as blowing agent into the extruder via a special injection tube.

[0051] The resulting polymer containing foaming agent is extruded through the hole of the die, cut off with a cutter, baked at 60° C., dried, and added with 0.1% by weight of magnesium stearate and 0.3% by weight of glycerin monohard Fatty acid ester lubrication.

[0052] The pellets were then foamed at different vaporization times and subsequently molded into the final product. The expandability results are shown in the table below.

Embodiment 2

[0054] Example 1 was repeated, adding 40 parts of a styrene / α-methylstyrene copolymer and 60 parts of the polystyrene used in Example 1.

[0055] A 6.2% mixture of n-pentane / iso-pentane 80 / 20 was fed into the extruder as blowing agent. The copolymer contained 6.5% alpha-methylstyrene and had a Mw of 155,000. The expandability results are shown in the table below.

Embodiment 3

[0056] Embodiment 3 (comparative example)

[0057] Example 1 was repeated, but using 98 parts of polystyrene with an MFI of 8 (Mw of 180,000), which is commercially available under the tradename Edistir N 1782 from ENICHEM S.p.A.

[0058] As can be seen from the table below, the product swells only very slightly, although it does not collapse.

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Abstract

Compositions of expandable vinylaromatic polymers which contain a polymer, of at least one vinylaromatic monomer, having an average molecular weight Mw ranging from 50,000 to 170,000, which comprise: a) 0-50% by weight of a copolymer obtained by polymerizing one or more vinylaromatic monomers and 0.1-15% by weight of an alpha-alkylstyrene; b) 0-10% by weight of a compatible polymer having a crystallinity lower than 10% and a glass transition temperature (Tg) higher than 100 DEG C, the remaining percentage consisting of the vinylaromatic polymer; c) 2-10% by weight, calculated with respect to the total, of an expanding agent; with the proviso that at least one of (a) or (b) is present in the polymeric mixture.

Description

technical field [0001] The present invention relates to compositions based on vinyl aromatic polymers having improved expandability. [0002] More specifically, the present invention relates to polystyrene-based compositions having improved expandability. Background technique [0003] Vinylaromatic polymers, polystyrene in particular, are known products that have been used for a long time for the manufacture of compact and / or foamed articles that can be used in various fields of application, the most important of which are household appliances, transport and Construction industry, office machines, etc. A particularly important field is that of thermal insulation, in which vinylaromatic polymers are used essentially in the form of foams. [0004] These foam products are obtained by pre-expanding an expandable polymer pre-impregnated with a blowing agent as pre-expanded granules and molding the pre-expanded granules contained in a closed mold by means of simultaneous pressur...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J9/00C08L25/04C08J9/16C08J9/14B29C44/00B29K25/00C08L25/06C08L25/08C08L71/12C09K3/16
CPCC08L25/06C08L25/04C08J2325/04C08L71/12C08J2425/00C08J2471/00C08L25/08C08J9/0066C08L2205/02C08J9/0061C08J9/16C08L2666/22C08L2666/06
Inventor A·卡萨利尼A·隆戈D·吉多尼R·兰弗雷迪
Owner POLIMERI EUROPA SPA