Diffusion behaviour of the acetaldehyde scavenger 2-aminobenzamide in polyethylene terephthalate for beverage bottles

Figures & data

Figure 1. Mechanism of the reaction of 2-aminobenzamide with acetaldehyde during PET pre-form manufacturing.

Table 1. Concentration of 2-aminobenzamide in natural mineral water after storage for 60 days at 40°C as well as at the end of the shelf life at RT storage.

Sample	Bottle volume (ml)	Storage conditions	Concentration
			Bottle wall (mg kg^–1)	Mineral water (µg l^–1)
Sample 2	1500	60 days at 40°C	262 ± 36	26.6 ± 2.6
Sample 3	1500	60 days at 40°C	291 ± 23	48.0 ± 11.3
Sample 4	500	60 days at 40°C	313 ± 35	52.1 ± 4.0
Sample 5	500	60 days at 40°C	319 ± 16	49.6 ± 2.7
Sample 6	500	60 days at 40°C	316 ± 17	55.3 ± 4.8
Sample 7	500	60 days at 40°C	229 ± 8	36.0 ± 5.1
Sample 8	500	60 days at 40°C	218 ± 14	37.8 ± 2.7
Sample 9	500	348 days at RT	258 ± 10	19.9 ± 2.6
Sample 10	500	390 days at RT	190 ± 30	14.1 ± 0.8
Sample 11	500	396 days at RT	233 ± 12	25.7 ± 2.2
Sample 12	1500	361 days at RT	238 ± 13	19.8 ± 1.5
Sample 13	1500	384 days at RT	261 ± 7	23.0 ± 1.8

Table 2. Result of the quantification of 2-aminobenzamide in kinetic test up to storage times of 60 days at 23°C and 40 days at 40°C (bottle wall concentration: 197.6 ± 2.7 mg kg^–1).

Storage time (days)	Concentration (µg l^–1)
	Mineral water		20% Ethanol
	23°C	40°C	23°C	40°C
3	–	8.3 ± 0.8	–	13.0 ± 1.1
6	–	12.4 ± 0.9	–	20.6 ± 1.7
10	4.5 ± 0.2	16.2 ± 0.3	6.6 ± 0.4	24.7 ± 1.9
20	6.2 ± 0.3	21.7 ± 0.8	7.4 ± 0.3	31.0 ± 4.5
31	7.7 ± 0.9	27.0 ± 0.2	10.0 ± 1.1	36.3 ± 1.3
40	10.6 ± 1.2	32.1 ± 1.8	10.8 ± 0.3	39.7 ± 1.5
51	12.3 ± 0.6	–	12.0 ± 0.8	–
60	12.4 ± 0.3	–	11.7 ± 0.5	–

Figure 2. Results of the migration kinetic of 2-aminobenzamide in mineral water and 20% ethanol at 23 and 40°C.

Table 3. Experimentally determined diffusion coefficient for 2-aminobenzamide in PET calculated from equation (1) with data from Table 1.

Simulant	Diffusion coefficient (cm^2 s^–1)
	23°C	40°C
Mineral water	4.2 × 10^–16	4.2 × 10^–15
20% Ethanol	4.7 × 10^–16	7.7 × 10^–15

Figure 3. (colour online) Predicted migration of 2-aminobenzamide into mineral water at 23°C as a function of the bottle wall concentration (calculated with D_P = 4.2 × 10^–16 cm² s^–1, partition coefficient K = 1, bottle wall thickness l = 300 µm, density of PET = 1.4 g cm^–3): (a) 500 ml bottle (surface area = 420 cm²), (b) 1000 ml bottle (surface area = 660 cm²) and (c) 1500 ml bottle (surface area = 840 cm²).

Figure 4. (colour online) Predicted migration of 2-aminobenzamide into mineral water at 40°C as a function of the bottle wall concentration (calculated with D_P = 4.2 × 10^–15 cm² s^–1, partition coefficient K = 1, bottle wall thickness l = 300 µm, density of PET = 1.4 g cm^–3): (a) 500 ml bottle (surface area = 420 cm²), (b) 1000 ml bottle (surface area = 660 cm²) and (c) 1500 ml bottle (surface area = 840 cm²).

Figure 5. (colour online) Predicted migration of 2-aminobenzamide into 20% ethanol at 40°C as a function of the bottle wall concentration (calculated with D_P = 7.7 × 10^–15 cm² s^–1, partition coefficient K = 1, bottle wall thickness l = 300 µm, density of PET = 1.4 g cm^–3): (a) 500 ml bottle (surface area = 420 cm²), (b) 1000 ml bottle (surface area = 660 cm²) and (c) 1500 ml bottle (surface area = 840 cm²).

Figure 6. (colour online) Predicted storage to reach the SML at 23°C as a function of the 2-aminobenzamide bottle wall concentration (calculated with D_P = 4.2 × 10^–16 cm² s^–1, partition coefficient K = 1, bottle wall thickness l = 300 µm, density of PET = 1.4 g cm^–3).