Heat Sealed Substrate

Abstract

A heat sealed substrate, the substrate being heat sealed with an aqueous polyolefin dispersion including an aqueous dispersion A including: A1, a copolymer of polyethylene and (meth)acrylic acid [E(M)AA] or a mixture of different copolymers of polyethylene and (meth)acrylic acid, A2, another polymer, not being a copolymer of polyethylene and (meth)acrylic acid, or a mixture of other polymers, and an optional additive; and an optional compound B, where compound B is a material dispersable or soluble in water and different from any of the ingredients of dispersion A.

Claims

1. A heat sealed substrate, the substrate being heat sealed with an aqueous polyolefin dispersion comprising a. from 50 to 100 wt. % of an aqueous dispersion A comprising the following ingredients: i. from 30 to 90 wt. % of A1, a copolymer of polyethylene and (meth)acrylic acid [E(M)AA] or a mixture of different copolymers of polyethylene and (meth)acrylic acid, ii. from 10 to 70 wt. % of A2, another polymer, not being a copolymer of polyethylene and (meth)acrylic acid, or a mixture of other polymers, and iii. from 0-15 wt. % of additive, b. from 0 to 50 wt. % of a compound B, where compound B is a material dispersable or soluble in water and different from any of the ingredients of dispersion A, wherein the wt. % of aqueous dispersion A and compound B is based on solid content of the whole aqueous polyolefin dispersion, the wt % of i.-iii. in dispersion A is based on solid content of dispersion A, the sum of the wt. % of i.-iii. in dispersion A is 100%, and A2 comprises one or more of copolymers of ethylene and vinyl acetate (EVA), copolymers of ethylene and vinyl acetate (EVA) modified with maleic anhydride, polyolefins modified with maleic anhydride, polyolefin elastomers, styrene butadiene block copolymers (SBS), random copolymers (SBC), ethylene-propylene-non-conjugated diene terpolymer (EPDM), maleic anhydride modified ethylene-propylene-non-conjugated diene terpolymer, and co- and terpolymers of ethane, propene, and 1-butene.

2. The heat sealed substrate according to claim 1 wherein the copolymer of polyethylene and (meth)acrylic acid has a content of (meth)acrylic based groups in the copolymer of at least 15 wt. %, wherein the wt. % is based on the total weight of the copolymer.

3. The heat sealed substrate according to claim 1 wherein all ingredients and compounds are food safe materials.

4. The heat sealed substrate according to claim 1 wherein A2 comprises one or more of copolymers of ethylene and vinyl acetate (EVA) and copolymers of ethylene and vinyl acetate (EVA) modified with maleic anhydride.

5. The heat sealed substrate according to claim 1 wherein the aqueous polyolefin dispersion contains dispersed hybrid particles containing both A1, the copolymer of polyethylene and (meth)acrylic acid, and A2, the another polymer not being a copolymer of polyethylene and (meth)acrylic acid.

6. A heat sealed substrate, the substrate being heat sealed with an aqueous polyolefin dispersion comprising aqueous dispersion A and compound B, wherein: dispersion A comprises the following ingredients: i. from 30 to 90 wt. % of A1, a copolymer of polyethylene and (meth)acrylic acid [E(M)AA] or a mixture of different copolymers of polyethylene and (meth)acrylic acid, ii. from 10 to 70 wt. % of A2, another polymer, not being a copolymer of polyethylene and (meth)acrylic acid, or a mixture of other polymers, and iii. from 0-15 wt. % of additive where compound B is a material dispersable or soluble in water and different from any of the ingredients of dispersion A, wherein: the wt. % of A and B is based on solid content of the whole aqueous polyolefin dispersion, the wt % of i.-iii. in dispersion A is based on solid content of dispersion A, the sum of the wt. % of i.-iii. in dispersion A is 100%, and A2 comprises one or more of copolymers of ethylene and vinyl acetate (EVA), copolymers of ethylene and vinyl acetate (EVA) modified with maleic anhydride, polyolefins modified with maleic anhydride, polyolefin elastomers, styrene butadiene block copolymers (SBS), random copolymers (SBC), ethylene-propylene-non-conjugated diene terpolymer (EPDM), maleic anhydride modified ethylene-propylene-non-conjugated diene terpolymer, and co- and terpolymers of ethane, propene, and 1-butene, and the aqueous polyolefin dispersion has been prepared by a process comprising providing the aqueous dispersion A in amount of at least 50 wt. % and the compound B in an amount of up to 50 wt. %: mixing all solid components of dispersion A at a temperature in the range of 50 C. to 200 C. after which a homogenous compound of all components is obtained and mixing the homogeneous compound with water, compound B, and a neutralizing agent at a temperature 2 to 20 C. above the highest melting temperature of all solid components of dispersion A until an aqueous dispersion is obtained wherein all dispersed particles have a particle size below 150 m.

7. The heat sealed substrate according to claim 6 wherein the mixing of the solid components of dispersion A is performed in a twin screw extruder.

8. The heat sealed substrate according to claim 6 wherein the mixing of the homogeneous compound with water, compound B and a neutralizing compound is performed under elevated pressure.

9. The heat sealed substrate according to claim 8 wherein the mixing of the homogeneous compound with water, compound B and a neutralizing compound is performed at a pressure which is higher than the vapor pressure of water at the mixing temperature.

10. The heat sealed substrate according to claim 1, wherein compound B comprises at least one of polyvinylpyrrolidone and polyethylene glycol.

11. The heat sealed substrate according to claim 1, wherein the substrate comprises aluminum.

12. The heat sealed substrate according to claim 6, wherein the substrate comprises aluminum.

13. The heat sealed substrate according to claim 1, wherein the substrate comprises aluminum foil.

14. The heat sealed substrate according to claim 6, wherein the substrate comprises aluminum foil.

Description

EXAMPLES

[0071] Various aqueous dispersions were prepared using the following procedure: [0072] In a first step a compound was prepared by mixing and kneading the individual ingredients in a Leistritz ZSE 18 Maxx twin screw extruder at a temperature in the range of 80-150 C. (temperature was selected based on the ingredients), where different temperature zones were created inside the extruder. The pressure inside the extruder was 35 bar maximum. [0073] In a next step the extruded compound was fed into a Bchi 21 Pressure reactor, equipped with a dissolver mixer operating at speeds between 100-1000 rpm. The dispersion was prepared at elevated temperature in the range of 90-150 C. at sometimes elevated pressure (additional pressure in the range of 0-100 bar).

[0074] The ingredients and conditions for each example are given in Table 1 below.

TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6* 7* Extruder EAA#3 80 80 60 80 50 100 EAA#9 100 POP#8 20 RP EVA #2 20 40 30 POE#11 20 PVP#31 15 PEG#40 5 Pressure Solid content 20 30 25 20 35 25 20 vessel (%) Base NH3 NH3 NH3 NH3 NH3 NH3 NaOH Temperature 100 90 100 100 100 90 110 ( C.) Overpressure 6-8 6-8 0-1 0-1 6-8 6 6-8 (bar) Rotational 500 500 1000 500 500 500 500 speed (revolutions per min) Viscosity (mPa*s) 12.5 170 310 6.7 213 471 PH 9.3 8.6 9.1 9.1 9.0 8.2 9.2 Average particle 53.5 17.9 26.3 45.9 33.4 23.5 size (m) Visual inspection A A B A A C D [0075] EAA #3: PRIMACOR 5980; dispersible polymer which is an ethylene acrylic acid copolymer (20 wt % comonomer), DOW [0076] EAA #9: Escor 5200, ethylene acrylic acid copolymer (15 wt % comonomer), ExxonMobil [0077] POP #8: AFFINITY GA 1950, POP, polyolefin plastomer containing Ethylen-1-Octen, DOW [0078] RP EVA #2: OREVAC T 9305, a random terpolymer of ethylene, vinyl acetate and maleic anhydride, ARKEMA [0079] POE #11: Vistamaxx 6202 POE; primarily composed of isotactic propylene repeat units with random ethylene distribution, ExxonMobil [0080] PVP #31: Kollidon 17 PF; soluble polyvinylpyrrolidone, Mw: 7000-11000, BASF [0081] PEG #40: Polyethylenglycol 10000, Mw: 9000-12500, Merck

Comparative Example

[0082] A: Milky dispersion [0083] B: Milky viscous dispersion [0084] C: dispersion with discrete particles [0085] D: High viscous paste