Method of decreasing aldehyde content in a polymeric material

Abstract

A method of decreasing aldehyde content in polymeric materials, for example in bottles comprising polyethylene terephthalate, uses a compound (A) which comprises first, second and third fragments which comprise a moiety Formula A) (A) and a moiety. (Formula B) NH (B). ##STR00001##

Claims

1. A polyester, having a reduced level of acetaldehyde, said polyester incorporating a compound (A) or a product of a reaction between compound (A) and aldehyde, wherein compound (A) includes: (I) a first fragment which comprises a moiety ##STR00034## and a moiety
NH  (B) wherein the carbon atom of moiety (A) and the nitrogen atom of moiety (B) are separated by at least one and not more than two atoms; (II) a second fragment which comprises a moiety ##STR00035## and a moiety
NH  (B) wherein the carbon atom of moiety (A) and the nitrogen atom of moiety (B) are separated by at least one and not more than two atoms; and (III) a third fragment which comprises a moiety ##STR00036## and a moiety
NH  (B) wherein said polyester is polyethylene terephthalate; and wherein said compound (A) is a liquid at 250° C.

2. A polyester according to claim 1, wherein the IV of the polyester is greater than 0.5 dL/g.

3. A polyester according to claim 1, wherein compound (A) includes: (I) a first fragment which comprises a moiety ##STR00037## and a moiety
NH  (B) wherein the carbon atom of moiety (A) and the nitrogen atom of moiety (B) are separated by at least one and not more than two atoms; (II) a second fragment which comprises a moiety ##STR00038## and a moiety
NH  (B) wherein the carbon atom of moiety (A) and the nitrogen atom of moiety (B) are separated by at least one and not more than two atoms; and (III) a third fragment which comprises a moiety ##STR00039## and a moiety
NH  (B).

4. A polyester according to claim 1, wherein the carbon atom of moiety (A) and the nitrogen atom of moiety (B) are separated by two atoms which are both unsaturated carbon atoms.

5. A polyester according to claim 1, wherein said first fragment comprises a moiety: ##STR00040## wherein R′ represents a substituent and n1 is 0 to 4; wherein moiety (B) in said first fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2.

6. A polyester according to claim 5, wherein said second fragment comprises a moiety: ##STR00041## wherein R′ represents a substituent and n1 is 0 to 4; wherein moiety (B) of said second fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2; wherein said third fragment comprises a moiety: ##STR00042## wherein R′ represents a substituent and n1 is 0 to 4; wherein moiety (B) of said third fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2.

7. A polyester according to claim 1, wherein said first fragment, said second fragment and said third fragment are bonded to a main fragment of compound (A) via the nitrogen atoms of moiety CO.NH of respective moieties (A) of said first fragment, said second fragment and said third fragment.

8. A polyester according to claim 7, wherein said main fragment consists of carbon and hydrogen atoms and only one other type of atom which is selected from oxygen and nitrogen atoms.

9. A polyester according to claim 8, wherein said main fragment is saturated.

10. A polyester according to claim 9, wherein said main fragment includes no primary amine moieties except primary amine moieties which are separated from a carbonyl moiety by at least one and not more than two atoms.

11. A polyester according to claim 1, wherein compound (A) includes first, second and third fragments which comprise a moiety ##STR00043## wherein a linking moiety L.sup.2 is arranged between said first, second and third fragments to which said first, second and third fragments are bonded at spaced apart positions, wherein the linking moiety is bonded to the benzene moieties of moiety (AA).

12. A polyester according to claim 1, wherein: the carbon atom of moiety (A) and the nitrogen atom of moiety (B) are separated by two atoms which are both unsaturated carbon atoms; said first fragment comprises a moiety: ##STR00044## wherein R′ represents a substituent and n1 is 0 to 4; moiety (B) in said first fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2; said second fragment comprises a moiety: ##STR00045## wherein R′ represents a substituent and n1 is 0 to 4; moiety (B) of said second fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2; said third fragment comprises a moiety: ##STR00046## wherein R′ represents a substituent and n1 is 0 to 4; and wherein moiety (B) of said third fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2.

13. A polyester according to claim 1, wherein: said first fragment, said second fragment and said third fragment are bonded to a main fragment of compound (A) via the nitrogen atoms of moiety CO.NH of respective moieties (A) of said first fragment, said second fragment and said third fragment, wherein said main fragment is saturated; said main fragment includes substantially no primary amine moieties except primary amine moieties which are separated from a carbonyl moiety by at least one and not more than two atoms.

14. A polyester according to claim 2, wherein compound (A) includes: a first fragment which comprises a moiety: ##STR00047## wherein R′ represents a substituent and n1 is 0 to 4, wherein moiety (B) in said first fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2; a second fragment which comprises a moiety: ##STR00048## wherein R′ represents a substituent and n1 is 0 to 4; wherein moiety (B) of said second fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2; a third fragment which comprises a moiety: ##STR00049## wherein R′ represents a substituent and n1 is 0 to 4.

15. A container or preform for a container, wherein said container or preform comprise a polyester as claimed in claim 1.

16. A container or preform according to claim 15, wherein said first fragment comprises a moiety: ##STR00050## wherein R′ represents a substituent and n1 is 0 to 4; wherein moiety (B) in said first fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2; wherein said second fragment comprises a moiety: ##STR00051## wherein R′ represents a substituent and n1 is 0 to 4; wherein moiety (B) of said second fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2; wherein said third fragment comprises a moiety: ##STR00052## wherein R′ represents a substituent and n1 is 0 to 4; wherein moiety (B) of said third fragment is NH.sub.2 and/or the NH moiety bonded to the benzene moiety is NH.sub.2.

Description

EXAMPLE 1—GENERAL PROCEDURE FOR PREPARATION OF ACETALDEHYDE SCAVENGERS

(1) Compounds having at least three primary amine groups, for example, the specific compounds detailed above, may be reacted with isatoic anhydride according to the reaction scheme below (where Mf represents “main fragment”)

(2) ##STR00030##

(3) The amount of isatoic anhydride is selected to derivatise all primary amine functional groups of the amine-containing compound.

EXAMPLE 2—GENERAL PROCEDURE FOR PREPARATION OF PREFORMS

(4) PET resin is dried prior to use using Con-Air (Trade Mark) dryers for at least four hours at 160° C.

(5) Prior to injection moulding, acetaldehyde scavenger as a dispersion, mixture or liquid is added to hot dry PET pellets and tumble mixed to ensure good dispersion of the scavenger.

(6) Bottle preforms can be produced using an injection moulding machine fitted with an appropriate preform tool.

EXAMPLE 3—GENERAL PROCEDURE FOR DETERMINING ACETALDEHYDE CONTENT OF PREFORM SAMPLES

(7) The acetaldehyde content of samples is determined on preform samples that have been cryo-ground to less than 1 mm. The level of acetaldehyde is determined using an Agilent 6890N gas chromatograph with a headspace sample changer and FID detector. Acetaldehyde reductions are calculated on the basis of percentage reduction seen in the acetaldehyde levels of a preform with additives, compared to that with no additives.

EXAMPLE 4—PROCEDURE FOR MEASURING OPTICAL PROPERTIES

(8) Plaques made in a manner similar to that described in Example 2 and relevant controls were made and optical properties (i.e. haze and L*) were assessed using a Minolta CM-3700d spectrophotometer in transmission mode fitted with a D65/10° light source.

EXAMPLE 5—PROCEDURE FOR DETERMINING MIGRATION OF ACETALDEHYDE SCAVENGER FROM PET

(9) Bottles blown from preforms incorporating selected acetaldehyde scavengers along with relevant controls were filled with water and placed in an oven at 60° C. for predetermined times. At various times, the water was sampled using HPLC to determine the level (if any) of migration of acetaldehyde scavengers into the water.

EXAMPLE 6—PREPARATION OF ACETALDEHYDE SCAVENGER USING TRIS(2-AMINOETHYL)AMINE

(10) The general procedure described in Example 1 was use with Tris(2-aminoethyl)amine to produce the compound below:

(11) ##STR00031##

EXAMPLE 7—PREPARATION OF ACETALDEHYDE SCAVENGER USING JEFFAMINE (TRADE MARK) T-403

(12) The general procedure described in Example 1 was used with JEFFAMINE T-403 to produce the compound below

(13) ##STR00032##

EXAMPLE 8 (COMPARATIVE), EXAMPLE 9 (COMPARATIVE) and EXAMPLE 10 (COMPARATIVE)

(14) Other compounds were used as follows:

EXAMPLE 8—ANTHRANILAMIDE

EXAMPLE 9—

(15) ##STR00033##

EXAMPLE 10—GRIVORY™ HB—A COMMERCIALLY AVAILABLE POLYAMIDE USED AS AN ADDITIVE IN PET BOTTLES

EXAMPLE 11—ASSESSMENT OF ACETALDEHYDE SCAVENGING ABILITY OF SELECTED MATERIALS

(16) Using the general procedure described in Example 3, compounds described in selected examples were assessed and results are provided below.

(17) Results relating to the acetaldehyde scavenging ability of the acetaldehyde scavenger of Example 8 are as follows:

(18) TABLE-US-00001 Average % aldehyde Concentration of concentration of reduction acetaldehyde acetaldehyde compared Description scavenger (ppm) (ppm) to control Control 0 14.44 Not applicable With acetaldehyde 250 7.38 49 scavenger of Example 8 With acetaldehyde 500 3.41 76 scavenger of Example 8 With acetaldehyde 1500 0.24 98 scavenger of Example 8

(19) Results relating to the acetaldehyde scavenging ability of the acetaldehyde scavenger of Example 9 are as follows:

(20) TABLE-US-00002 Average % aldehyde Concentration of concentration of reduction acetaldehyde acetaldehyde compared Description scavenger (ppm) (ppm) to control Control 0 11.74 Not applicable With acetaldehyde 250 5.52 53 scavenger of Example 9 With acetaldehyde 500 2.98 75 scavenger of Example 9 With acetaldehyde 1500 1.26 89 scavenger of Example 9

(21) Results relating to the acetaldehyde scavenging ability of the acetaldehyde scavenger of Example 6 are as follows:

(22) TABLE-US-00003 Average % aldehyde Concentration of concentration of reduction acetaldehyde acetaldehyde compared Description scavenger (ppm) (ppm) to control Control 0 8.78 Net applicable With acetaldehyde 250 3.86 56 scavenger of Example 6 With acetaldehyde 500 2.45 72 scavenger of Example 6 With acetaldehyde 1500 0.88 90 scavenger of Example 6

(23) Results relating to the acetaldehyde scavenging ability of the acetaldehyde scavenger of Example 7 are as follows:

(24) TABLE-US-00004 Average % aldehyde Concentration of concentration of reduction acetaldehyde acetaldehyde compared Description scavenger (ppm) (ppm) to control Control 0 9.53 Not applicable With acetaldehyde 250 6.20 35 scavenger of Example 7 With acetaldehyde 500 4.85 49 scavenger of Example 7 With acetaldehyde 1500 2.76 71 scavenger of Example 7

(25) It should be appreciated from the results that the acetaldehyde reduction achieved using the scavengers of Examples 6 and 7 is comparable to that of the commercially available scavengers of Examples 8 and 9. However, use of the scavengers of Examples 6 and 7 is found to be advantageous for other reasons discussed herein.

EXAMPLE 12—COMPARISON OF OPTICAL PROPERTIES OF PLAQUES INCORPORATING SELECTED ACETALDEHYDE SCAVENGERS

(26) Using the general procedure described in Example 4, compounds as described in selected examples were compared.

(27) Firstly, a comparison was undertaken between optical properties of virgin PET (C93 PET), the polyamide of Example 10 and the anthranilamide-derivative of Example 9 and results are provided below.

(28) TABLE-US-00005 Example No. of Addition rate of L* of % Haze of additive used additive moulding moulding No additive — 89.46 1.99 (virgin PET) Example 10 0.3 wt % 89.02 4.45 Example 9 0.1 wt % 88.51 2.23

(29) Note that 0.3 wt % of the Example 10 material was used since the material is substantially less active (on a weight for weight basis) compared to the Example 9 material. Amounts of additives were selected to provide similar levels of acetaldehyde reduction.

(30) The comparison illustrates how a high molecular weight material (Example 10) tends to produce significantly more haze than a lower molecular weight material. It will be appreciated that high levels of haze are undesirable.

(31) Secondly, a comparison was undertaken between optical properties of preforms incorporating the acetaldehyde scavengers of Examples 6, 7 and comparative Examples 8 and 9 (using the procedure generally described in Example 4 applied to preforms), at a range of loadings. Between each different acetaldehyde scavenger, a new control was assessed for calibration purposes. Results are provided in the table below.

(32) TABLE-US-00006 Concentration of acetaldehyde Description scavenger (ppm) L*(D65) Haze Control 1 — 85.812 45.496 With acetaldehyde 250 85.812 46.142 scavenger of Example 8 With acetaldehyde 500 85.764 45.878 scavenger of Example 8 With acetaldehyde 1500  85.142 45.656 scavenger of Example 8 Control 2 — 85.980 45.422 With acetaldehyde 250 85.818 46.568 scavenger of Example 9 With acetaldehyde 500 85.450 46.332 scavenger of Example 9 With acetaldehyde 1500  85.424 45.888 scavenger of Example 9 Control 3 — 86.104 44.99  With acetaldehyde 250 85.206 45.162 scavenger of Example 6 With acetaldehyde 500 85.200 45.818 scavenger of Example 6 With acetaldehyde 1500  84.734 45.766 scavenger of Example 6 Control 4 — 86.092 46.304 With acetaldehyde 250 85.584 45.772 scavenger of Example 7 With acetaldehyde 500 85.068 45.76  scavenger of Example 7 With acetaldehyde 1500  84.344 46.034 scavenger of Example 7

(33) The results show that the Examples 6 and 7 acetaldehyde scavengers have surprisingly little effect on the optical properties of the bottles, despite their significantly higher molecular weights compared to the Example 8 and 9 scavengers. This result is contrary to expectations, as, for example, illustrated by the effect on optical properties when the high molecular weight Example 10 material is incorporated into PET.

EXAMPLE 13—COMPARISON OF MIGRATION OF SELECTED ACETALDEHYDE SCAVENGERS FROM PREFORMS

(34) Using the general procedure described in Example 5, compounds as described in selected examples were compared over predetermined periods of time. For each scavenger, multiple bottles were produced and assessed.

(35) The following tables detail results:

(36) TABLE-US-00007 HPLC Grade Water in 330 ml bottle 60° C. 1500 ppm of Example 8 scavenger ppm of Example 8 ppm of Example 8 Bottle-injection scavenger after 10 days scavenger after 30 days 1-1 0.48 0.68 1-2 0.47 0.69 2-1 0.42 0.65 2-2 0.40 0.68 3-1 0.40 0.70 3-2 0.41 0.72 4-1 0.40 0.64 4-2 0.41 0.65 5-1 0.41 0.71 5-2 0.39 0.68

(37) TABLE-US-00008 HPLC Grade Water in 330 ml bottle 60° C. 1500 ppm of Example 9 scavenger ppm of Example 9 ppm of Example 9 Bottle-injection scavenger after 10 days scavenger after 30 days 1-1 ND <0.24 1-2 ND <0.24 2-1 ND <0.24 2-2 ND <0.24 3-1 ND <0.24 3-2 ND <0.24 4-1 ND <0.24 4-2 ND <0.24 5-1 ND <0.24 5-2 ND <0.24

(38) Note that where the ppm of scavenger is stated to be <0.24 ppm, this means that a peak was observed for the molecule. The lower limit of detection is 0.1 ppm but to quantify the amount needs to be greater than 0.24 ppm.

(39) In the case of the Examples 6 and 7 acetaldehyde scavengers, no scavenger was observed by HPLC in the water after more than 60 days, whilst the Example 8 and 9 scavengers were detected showing the level of migration of the Example 8 and 9 scavengers is greater than for the Example 6 and 7 scavengers.

(40) Thus, it should be appreciated that the Example 6 and 7 acetaldehyde scavengers provide high levels of acetaldehyde scavenging at acceptable additional rates in PET, whilst not significantly impacting optical properties (e.g. L* and haze) and they exhibit a low level of migration from the PET. Furthermore, the Example 6 and 7 scavengers are of relatively low volatility and exhibit relatively low volatility during processing.

(41) The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.