# US 8,772,362 B1 · Expanded polystyrene made using D-limonene as a plasticizer

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- Number: US 8,772,362 B1
- Document ID: US8772362B1
- Status: Granted
- Kind: B1
- Application number: 14/102,731
- Filed: 2013-12-11
- Granted: 2014-07-08
- Earliest claimed: 2013-02-15
- Assignees: Nexkemia Petrochimie Inc.
- Applicants: Jean-Pierre Gibeault
- Inventors: Jean-Pierre Gibeault
- Web page: https://patentgrep.com/patent/US8772362B1

## CPC

- C08J 9/20: by suspension polymerisation in the presence of the blowing agent
- C08J 9/0019: {halogenated}
- C08J 9/232: by sintering expandable particles
- C08J 2203/14: Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons
- C08J 2325/06: Polystyrene
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)

## Abstract

Disclosed is a process for production of expanded polystyrene using D-limonene as a plasticizer, which allows reducing the amount of pentane in the process, yet allows generating beads with similar cell size as if greater quantities of pentane had been used. Pentane is an organic solvent with toxicity associated with organic solvents.

## Claims

### Claim 1

A process of forming expanded polystyrene beads having internal cells of a size typically generated by including a larger amount of pentane in the formulation, comprising:
heating a mixture of styrene, demineralized water, brominated flame retardant chemicals, a peroxide first polymerization initiator, paraffin, tricalcium phosphate (TCP), a surfactant, an extender and D-limonene to a first polymerization temperature;
adding 3-8% by weight pentane and a second polymerization initiator to the mixture and heating to a second polymerization temperature to form EPS beads having cells as large as if about 25% more pentane was used than the amount of pentane which actually was used.

### Claim 2 (depends on 1)

The process of claim 1 wherein the brominated compounds are decabromodiphenyl oxide, phenoxy tetrabromnobisphenol A, or tetrabromobisphenol A bis(allyl ether), hexabromocyclododecane, and brominated polymer.

### Claim 3 (depends on 1)

The process of claim 1 wherein the tricalcium phosphate (TCP) is in the form of fine particles.

### Claim 4 (depends on 1)

The process of claim 1 wherein the extender is dodecylbenzenesulfonate or a persulfate salt.

### Claim 5 (depends on 4)

The process of claim 4 wherein the persulfate salt is ammonium or potassium persulfate.

### Claim 6 (depends on 1)

The process of claim 1 wherein the surfactant is a combination of a molecular colloid and an inorganic alkali metal salt.

### Claim 7 (depends on 6)

The process of claim 6 wherein the molecular colloid is polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) and the inorganic alkali metal salt is Mg2P2O7, Ca3(PO4)2 or another alkali metal salt including salts of sulfates, chlorides, carbonates or hydrogencarbonates.

### Claim 8 (depends on 1)

The process of claim 1 wherein the peroxide is dibenzoyl peroxide, hydrogen peroxide 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, or hydrogen peroxide.

### Claim 9 (depends on 1)

The process of claim 1 wherein the second polymerization initiator is tert-butyl perbenzoate, tert-butyl peroxy-2-ethylhexanoate, t-butyl ethylhexylmonoperoxycarbonate or t-amyl ethylhexylmonoperoxycarbonate.

### Claim 10 (depends on 1)

The process of claim 1 further including melting the beads produced by the process of claim 1 inside a mold to form objects in the shape of the mold.

### Claim 11 (depends on 10)

The process of claim 10 wherein the melting of the beads is with steam.