Basic Methacrylate Copolymer

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Residue Monograph prepared by the meeting of the Joint FAO/WHO Expert Committee on Food Additives (JECFA), 86th Meeting 2018

BASIC METHACRYLATE COPOLYMER

This monograph was also published in: Compendium of Food Additive Specifications. Joint FAO/WHO Expert Committee on Food Additives (JECFA), 86th meeting 2018. FAO JECFA Monographs 22

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BASIC METHACRYLATE COPOLYMER

New specifications prepared at the 86th JECFA (2018) and published in FAO JECFA Monographs 22 (2018). An ADI of “not specified” was established at 86th JECFA (2018).

SYNONYMS E 1205; INS No. 1205; basic butylated methacrylate copolymer; amino methacrylate copolymer; aminoalkyl methacrylate copolymer E; butyl methacrylate; dimethylaminoethyl methacrylate; methyl methacrylate polymer; butyl methacrylate; methyl methacrylate; dimethylaminoethyl methacrylate copolymer

DEFINITION Basic Methacrylate Copolymer is a cationic copolymer comprised of the monomers dimethylaminoethyl methacrylate, butyl methacrylate and methyl methacrylate in the molar ratio of 1:2:1. The copolymer is manufactured by a controlled polymerization process using a free radical donor initiation system. After completion of polymerization, the viscous copolymer solution is fed into an extruder to remove solvents and volatile substances, by actively degassing through vacuum and heating. The solid granules of basic methacrylate copolymer formed in the extruder can be milled to a powder. The copolymer may contain residual monomers (dimethylaminoethyl methacrylate, butyl methacrylate, methyl methacrylate).

Chemical name Poly(butyl methacrylate-co-(2-dimethylaminoethyl)methacrylate-co- methyl methacrylate)

C.A.S. number 24938-16-7

Chemical formula Poly[(CH2:C(CH3)CO2(CH2)2N(CH3)2)-co-(CH2:C(CH3)CO2CH3)-co- (CH2 :C(CH3)CO2(CH2)3CH3)]

Structural formula

••• •••

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The above formula is provided for illustrative purposes; specific repeat units cannot be defined.

Formula weight 47,000 (weight-average), 22,000 (number-average)

Assay 20.8 – 25.5 % dimethylaminoethyl (DMAE) groups on the dried basis

See description under TESTS

DESCRIPTION White powder

FUNCTIONAL USES Coating agent, glazing agent

CHARACTERISTICS

IDENTIFICATION

Viscosity 3 - 6 mPa∙s

Determine viscosity using Brookfield viscometer at 20° and 30 rpm using UL adapter.

Refractive index n : 1.380 - 1.385 (Vol. 4) 20 D

Solubility (Vol. 4) Freely soluble in methanol, ethanol, and 1 N aqueous hydrochloric acid

Infrared absorption The infrared absorption spectrum of a dry film of sample corresponds to the infrared spectrum in the Appendix.

Apply one drop of sample to a glass plate, cover with a water- resistant crystal disc (AgCl, KRS 5), press lightly, remove the crystal disc and dry for about 15 minutes at 60°.

PURITY

Loss on drying (Vol. 4) Not more than 2.0% (110°, 3 h)

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Sulfated ash (Vol. 4) Not more than 0.1%

Test 5 g of the sample (Method I)

Particle size < 50 μm: at least 95 % < 20 μm: at least 50 % < 3 μm: not more than 10 %

See description under TESTS

Residual solvents Methanol: Not more than 50 mg/kg; (Vol. 4) Butanol: not more than 50 mg/kg and

Propan-2-ol: not more than 100 mg/kg.

(See General Methods, Organic Components, Residual Solvents, Method 1)

Residual monomers Dimethylaminoethyl methacrylate: Not more than 500 mg/kg

Butyl methacrylate: Not more than 100 mg/kg

Methyl methacrylate: Not more than 50 mg/kg

See description under TESTS

Lead (Vol. 4) Not more than 1.0 mg/kg

Determine using a method appropriate to the specified level. The selection of sample size and method of sample preparation may be based on principles of methods described in Volume 4 (under “General Methods, Metallic Impurities”).

Microbiological criteria Total plate count: Not more than 1,000 cfu/g (Vol. 4) Yeast and moulds: Not more than 100 cfu/g

Coliforms: Negative in 10 g

TESTS

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PURITY TESTS

Particle size Determine using the light diffraction measurement method according to Ph. Eur. 2.9.31

(European Pharmacopeia; Particle Size Analysis by Laser Light Diffraction. 8 01/2010:0333)

Residual monomers Method for the determination of methyl methacrylate and butyl methacrylate:

Standards and Reagents: Phosphate buffer (0.0625 M, pH 2.0): Prepare an aqueous solution containing 8.9 g of anhydrous dibasic sodium phosphate and 8.5 g of monobasic potassium phosphate in 1 L deionized water. Adjust with phosphoric acid to pH 2.0.

Mobile phase: Prepare a mixture of methanol and pH 2.0 phosphate buffer (55:45).

Diluent: Acetonitrile:Buffer (40:60)

Preparation of standard solution Stock mixed standard solution: Accurately weigh 20 mg of butyl methacrylate and 10 mg of methyl methacrylate, dissolve in 3 ml of n-butanol and dilute to volume to 10 ml with diluent in a volumetric flask.

Intermediate mixed standard solution: Pipette 1.0 ml of stock mixed standard solution into a 10 ml volumetric flask and dilute to 10 ml with diluent.

Working mixed standard solution: Pipette 1.0 ml of intermediate standard solution into a 25 ml volumetric flask and dilute to volume with diluent. This solution contains about 8 µg/ml of butylmethacrylate and 4 µg/ml of methyl methacrylate.

Preparation of Sample solution

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Accurately weigh about 1.0 g of sample, dissolve in diluent and make up to 50 ml with diluent and mix.

Procedure Chromatographic system: The liquid chromatograph is equipped with a UV/diode array detector capable of working at 205 nm and a column (4.6 mm × 12 cm, packing material: octadecylsilane chemically bonded to porous silica or ceramic microparticles, 1.5-10 µm)). Flow rate: 2 ml/min.

Chromatograph the working standard solution, and record the peak responses. The resolution, R, between butyl methacrylate and methyl methacrylate is not less than 10; and the relative standard deviation for replicate injections is not more than 3.0%.

Separately inject 50 µl each of the working standard solution and sample solution and record the peak areas of the monomers.

Calculate the quantity of each monomer in the sample using the formula:

Monomer concentration (µg/g) = (rU/rS) × (CS/CU) × F rU = Peak area for the monomer in the sample chromatogram rS = Peak area for the monomer in the working standard chromatogram CS = Concentration of monomer in the working standard solution (µg/ml) CU = Concentration of polymer in the sample solution (mg/ml) F = Conversion factor (103 mg/g)

Method for the determination of 2-Dimethylaminoethyl methacrylate

Standards and Reagents: Monobasic potassium phosphate buffer solution (0.025M): Prepare an aqueous solution containing 3.4 g of monobasic potassium phosphate per litre.

Mobile phase: Tetrahydrofuran:monobasic potassium phosphate buffer solution (75:25).

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Preparation of standard solution Stock standard solution (200 µg/ml): Accurately weigh about 20 mg of (2-dimethylaminoethyl) methacrylate, dissolve in tetrahydrofuran, make up to volume in a 10 ml volumetric flask with tetrahydrofuran and mix.

Working standard solution (8 µg/ml): Dilute 2.0 ml of the stock standard solution to 50 ml in a volumetric flask with tetrahydrofuran and mix.

Preparation of Sample solution Accurately weigh about 1.0 g of sample, dissolve in tetrahydrofuran, dilute to 50 ml with tetrahydrofuran in a volumetric flask and mix.

Procedure Chromatographic system: The liquid chromatograph is equipped with a UV/diode array detector capable of working at 215 nm and a column (4.6 mm × 12 cm, packing material: an essentially monomolecular layer of aminopropylsilane chemically bonded to totally porous silica gel support, 1.5-10 µm) . Flow rate: 2 ml/min.

Chromatograph the working standard solution, and record the peak area. The relative standard deviation for replicate injections is not more than 2.0%.

Separately inject 50 µl of the working standard solution and the sample solution and record the peak areas.

Calculate the quantity of each monomer in the sample using the formula”

2-Dimethylaminoethyl methacrylate, (µg/g) = (rU/rS) × (CS/CU) × F

rU = Peak area for the monomer in the sample chromatogram rS = Peak area for the monomer in the standard chromatogram CS = Concentration of monomer in the working standard solution (µg/ml) CU = Concentration of polymer in the sample solution (mg/ml) F = Conversion factor (103 mg/g)

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METHOD OF ASSAY Determine the percentage of Dimethylaminoethyl (DMAE) groups using a potentiometric titration.

Dissolve 200 mg of dried sample in 4 ml water and 96 ml of glacial acetic acid. Titrate with 0.1 N standard perchloric acid solution to a potentiometric end point. Perform a blank determination.

(% / , ) ( ) × × 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔 = 𝑤𝑤 𝑤𝑤 𝑜𝑜𝑜𝑜 𝑡𝑡ℎ𝑒𝑒 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑 𝑏𝑏𝑏𝑏 𝑏𝑏𝑏𝑏𝑏𝑏× 100 𝑉𝑉𝑉𝑉 − 𝑉𝑉𝑉𝑉 𝑁𝑁 𝐹𝐹 𝑊𝑊 VS = titrant volume consumed by the sample (ml) VB = titrant volume consumed by the blank (ml) N = actual normality of the titrant (mEq/ml) F = equivalency factor, 72.1 mg/mEq W = dried sample weight (mg)

Appendix: Infrared spectrum of basic methacrylate copolymer

90 % T 80 r 70 a n 60 s m 50 i t 40 t 30 a n 20 c e 10

4000 3000 2000 1000 Wavenumbers (cm-1)