METHOD AND APPARATUS FOR MANUFACTURING SUSTAINABLE PRODUCTS WITH A BLOWN, FOAM STRUCTURE

• US 20150054190A1
• Filed: 03/11/2013
• Published: 02/26/2015
• Est. Priority Date: 03/12/2012
• Status: Active Grant

• Current Assignee: Paperfoam B.V.
• Original Assignee: Paperfoam B.V.
• Inventors: Huisman, Jan Wietze, Zandstra, Nynke Margaretha, Arentsen, Johan Hendrik Adolf, Geerts, Hugo Mark
• Granted Patent: US 10,442,121 B2
• Time in Patent Office: Days
• US Class Current: 264/50
• CPC Class Codes: B29C 44/08 using several expanding or moulding steps
• CPC Class Codes: B29C 44/3403 Foaming under special conditions, e.g. in sub-atmospheric pressure, in or on a liquid
• CPC Class Codes: B29C 44/3415 Heating or cooling
• CPC Class Codes: B29C 44/3442 Mixing, kneading or conveying the foamable material mixing plastics B29B7/00; mixing in general B01F
• CPC Class Codes: B29C 44/348 by regulating the temperature and/or the pressure, e.g. suppression of foaming until the pressure is rapidly decreased
• CPC Class Codes: B29C 44/3496 The foam being compressed and later released to expand B29C44/3465 takes precedence
• CPC Class Codes: B29C 44/462 provided with pre-foaming devices
• CPC Class Codes: B29C 45/1701 using a particular environment during moulding, e.g. moisture-free or dust-free
• CPC Class Codes: B29K 2003/00 Use of starch or derivatives as moulding material
• CPC Class Codes: B29L 2031/772 Articles characterised by their shape and not otherwise provided for closed loop B29L2031/709; ring-like B29L2031/7096; corrugated B29L2016/00, flat B29L2007/00; hollow B29L2022/00; screw-threaded B29L2001/00; toothed B29L2031/775; corrugated tubes B29L2023/18
• CPC Class Codes: C08L 1/02 Cellulose; Modified cellulose
• CPC Class Codes: C08L 3/02 Starch; Degradation products thereof, e.g. dextrin
• CPC Class Codes: C08L 5/00 Compositions of polysaccharides or of their derivatives not provided for in groups C08L1/00 or C08L3/00

Abstract

A method for manufacturing sustainable products with a blown, foam structure, wherein a mass comprising at least natural polymers such as starch is passed under pressure into a mould cavity (4) or through a mould die, and the mass is heated in the mould in a manner such as to stabilize the foamed structure to form the product, wherein the method comprises prefoaming of the mass prior to injection in the mould. Preferably, the prefoamed mass is kept under pressure until insertion in the mould. The invention further relates to an apparatus to be used in said method.

Claims

1. A method for manufacturing sustainable products with a blown, foam structure, wherein a mass comprising at least natural polymers such as starch is passed under pressure into a mould cavity (4) or through a mould die, and the mass is heated in the mould to stabilize the foamed structure to form the product, wherein the method comprises prefoaming of the mass prior to injection in the mould.

2. A method according to claim 1, wherein prefoaming of the mass comprises actively inserting an amount of gas into the mass containing the natural polymers to form a mass with entrapped gas bubbles, wherein during prefoaming pressure is applied to the mass.

3. A method according to claim 1, wherein the prefoamed mass is kept under pressure until insertion in the mould, wherein a pressure inside the mould cavity is lower than the pressure applied to the prefoamed mass before insertion thereof into the mould cavity.

4. A method according to claim 1, wherein the prefoaming comprises introducing a gas, such as oxygen, nitrogen or carbon dioxide, in a liquid mass comprising at least said natural polymers to form a prefoamed mass having a lower density than the liquid mass prior to prefoaming.

5. A method according to claim 1, wherein the mass is formed by a liquid batter comprising a suspension or solution of at least the natural polymers such as starch in a liquid.

6. A method according to claim 1, wherein a ratio of the volume of the prefoamed mass with respect to the volume of the mass before prefoaming is approximately between 1:

1.6 and 1;

1.2.

7. A method according to claim 1, wherein the prefoamed mass is kept under pressure during prefoaming, said pressure preferably being approximately between 3×

10⁵ N/m² (3 bar) and 6×

10⁵ N/m² (6 bar), for instance approximately 5×

10⁵ N/m² (5 bar).

8. A method according to claim 7, wherein the density of the prefoamed mass is approximately 200-400 grams/litre, measured at atmospheric pressure (1.01×

10⁵ N/m² (1.01 bar).

9. A method according to claim 1, wherein the prefoamed mass after leaving the prefoaming means (12) and before supplying said mass to the mould (4) is kept under pressure, for instance under a pressure of approximately 5×

10⁵ N/m² (5 bar).

10. A method according to claim 9, wherein the prefoamed mass after leaving the prefoaming means (12) has a density of approximately 700-800 grams/litre.

11. A method according to claim 1, wherein the prefoamed mass is kept under pressure during inserting said mass into the mould cavity, wherein the pressure is approximately between 2×

10⁵ N/m² (2 bar) and 4×

10⁵ N/m² (4 bar), for instance approximately 3×

10⁵ N/m² (3 bar).

12. A method according to claim 1, wherein as mould an injection mould is used.

13. A method according to claim 1, wherein the mould is heated to approximately the baking temperature prior to introduction of the prefoamed mass into the mould, wherein the temperature of the mould is preferably brought to approximately 180°

C.-240°

C., more preferably to approximately 180°

C.-225°

C.

14. A method according to claim 1, wherein the prefoamed mass comprises a blowing agent, preferably at least water, wherein the mass contains at least 10% of weight of water.

15. A method according to claim 1, wherein the method further comprises inserting additives to the mass during or after prefoaming of said mass.

16. A method according to claim 15, wherein the additive may comprise at least one of a cross linker, stabilizer, foaming agent and colouring agent.

22. An apparatus according to claim 15, wherein the apparatus is configured to control insertion of the amount of prefoamed mass into the mould cavity based on volume and/or time.

17. An apparatus for manufacturing sustainable products with a blown, foam structure comprising a mould (4) which contains at least one mould cavity or a mould die and supply means for feeding a mass under pressure into the or each mould cavity or through the mould die, wherein the apparatus (1) comprises heating means (22) for heating the mould and wherein the apparatus comprises prefoaming means (12) provided upstream the supply means (6) for prefoaming the mass.

18. An apparatus according to claim 17, wherein the prefoaming means are configured for keeping the prefoamed mass under pressure.

19. An apparatus according to claim 18, wherein the prefoaming means comprises a pressure regulator (14) for bringing and/or keeping the prefoamed mass under a pressure of approximately between 3×

10⁵ N/m² (3 bar) and 6×

10⁵ N/m² (6 bar), for instance approximately 5×

10⁵ N/m² (5 bar).

20. An apparatus according to claim 17, wherein between the prefoaming means (12) and the supply means (6) a pressure conduit (16) is provided having a pressure control (18) to keep the pressure in the conduit substantially constant, for instance at approximately 5×

10⁵ N/m² (5 bar).

21. An apparatus according to claim 18, wherein the supply means (6) comprises a pressure control 20 to bring and/or keep the pressure during insertion of the mass into the mould cavity substantially constant, for instance at substantially 3×

10⁵ N/m² (3 bar).