MASH FILTER MEMBRANE

Abstract

The invention is directed to a mash filter membrane comprising an elastomeric composition that comprises more than 50 wt % of one or more elastomer, based on the total weight of polymers in the elastomeric composition.

Claims

1. Mash filter membrane comprising an elastomeric composition that comprises more than 50 wt % of one or more elastomer, based on the total weight of polymers in the elastomeric composition.

2. Mash filter membrane in accordance with claim 1, wherein the elastomeric composition comprises more than 60, preferably more than 80, preferably more than 90, more preferably more than 95, most preferably about 100 wt % of said elastomers, based on the total weight of polymers in the elastomeric composition.

3. Mash filter membrane in accordance with claim 1, wherein said elastomer comprises a copolymer preferably one or more block-copolymer selected from the group consisting of triblock copolymers polystyrene-block-polybutadiene-block-polystyrene (SBS) and polystyrene-block-polyisobutene-block-polystyrene (SIS), wherein said elastomer comprises an olefinic elastomer, preferably one or more selected from the group consisting of ethylene propylene rubber (EPR), nitrile butadiene rubber (NBR), EPDM and polystyrene-co-polybutadiene rubber (SBR), or wherein said elastomer comprises one or more selected from the group consisting FKM (according to ASTM D1418 standard—e.g. Viton™) and FFKM (according to ASTM D1418 standard—e.g. Kalrez™) and NBR, most preferably, the elastomer comprises EPDM.

4. Mash filter membrane in accordance with claim 1, having a compression set determined after 72 hours at 70° C. according to ISO 815-1:2014, method A, test piece B, of less than 35%, preferably less than 25%, wherein the compression set is determined before use of said membrane.

5. Mash filter membrane in accordance with claim 1, having a compression set determined after 72 hours at 70° C. according to ISO 815-1:2014, method A, test piece B, of less than 50%, preferably less than 25%, more preferably less than 20% wherein the compression set is determined after 4700 brews or 90 weeks of using said membrane.

6. Mash filter membrane in accordance with claim 1, wherein the elastomeric composition, before use of said membrane, has one or more, preferably all of the following material properties: a tensile strength determined according to ISO 37:2011, type 2, of more than 5, preferably more than 8, more preferably more than 10 MPa, such as about 12 MPa; a modulus M300 deformation determined according to ISO 37:2011, type 2, of more than 4, preferably more than 4.5, more preferably more than 5 MPa, such as about 8.6 MPa; an elongation at break determined according to ISO 37:2011, type 2, of more than 200%, preferably more that 300%, most preferably more than 400%,such as about 420%; a density determined according to UNI EN ISO 1183-1, of more than 1 g/cm.sup.3, such as about 1.06 g/cm.sup.3; a Shore A hardness determined according to UNI ISO 7619-1, in the range of 60 to 75, preferably 65 to 71 ShA, such as about 66 ShA.

7. Mash filter membrane in accordance with claim 1, wherein the elastomeric composition is a food grade composition such as according to EU Directive 95/2001/EC on general product safety, Regulation (EC) N. 1935/2004 on materials and articles intended to come into contact with food, EU Regulation 2023/2006 on good manufacturing practice for materials and articles intended to come into contact with food, Dutch Food and consumer items law (including but not limited to the (Commodities Act) decree and regulation on packaging and consumer items (“Warenwetbesluit en—regeling verpakkingen en gebruiksartikelen”), article 33 of EU Regulation (EC) 1907/2006 such that no substances of very high concern as defined by the REACH legislation are present above 0.1% by weight, and/or according to Food and Drug Administration (FDA) CFR Title 21—Part 177—Indirect Food Additives: Polymers § 177.2600 Rubber articles intended for repeated use.

8. Mash filter membrane in accordance with claim 1, having a one-sided surface area of more than 1, preferably more than 2, more preferably more than 3, even more preferably more than 3.5, most preferably about 3.6 m.sup.2.

9. Mash filter membrane in accordance with claim 1, wherein the elastomeric composition is cured or crosslinked by peroxide.

10. Mash filter membrane in accordance with claim 1, wherein the elastomeric composition comprises less than 50% of one or more inelastic polymers, preferably less than 25%, more preferably less than 10%, based on the total weight of polymers in the elastomeric composition.

11. Mash filter membrane in accordance with claim 10, wherein the inelastic polymers are polyolefin homopolymers, preferably one or more polymers selected from the group of polyethylene, polypropylene, polystyrene and the like.

12. Mash filtration unit comprising the mash filter membrane in accordance with claim 1.

13. Use of the mash filter membrane in accordance with claim 1 in the filtration of mash.

14. Method for the production of the mash filter membrane in accordance claim 1, said method comprising blending of a melt of the elastomeric composition, preferably injection molding of the elastomeric composition.

15. Mash filter membrane that is obtainable by the method according to claim 14.

Description

COMPARATIVE EXAMPLE 1

Analysis of Conventional Membrane

[0030] A mash filter membrane of 2 by 1.8 m.sup.2 available from Meura S.A., Belgium, having a composition of 50 wt % EPDM and 50% PE was analyzed before use and the following material properties as indicated in Table 2 were found.

TABLE-US-00002 TABLE 2 Material property Method Value Density UNI EN ISO 1183-1 0.95 g/cm.sup.3 Shore A hardness UNI ISO 7619-1  75 ShA Tensile strength ISO 37:2011, type 2  8.1 MPa Elongation at break ISO 37:2011, type 2 548% Modulus 25% ISO 37:2011, type 2  2 Modulus 50% ISO 37:2011, type 2  2.6 Modulus 100% ISO 37:2011, type 2  3.2 Modulus 200% ISO 37:2011, type 2  4.2 Modulus 300% ISO 37:2011, type 2  5.1 Tear resistance, maximum ISO 34-1:2015, method C  59N force Tear resistance, tear ISO 34-1:2015, method C  24 kN/m resistance Compression set ISO 815-1:2014, method A  40%

EXAMPLE 2

Evaluation of Stickiness of Membranes

[0031] One mash filtration unit commercially available from Meura S.A. was equipped with 138 mash filter membranes as prepared in Example 1. Another mash filtration unit of the same type, was equipped with 138 conventional mash filter membranes are referred to in Comparative example 1. Both mash filtration units were placed in the same room, fed with the same brews (mash) and treated similarly (expect when maintenance was due, vide infra) as they were running parallel in the brewing process.

[0032] The stickiness of the membranes was analyses by regarding the required manual, operational assistance needed to remove the spent grain bed from membrane after a daily or monthly CIP. The results are provided in Table 3.

TABLE-US-00003 TABLE 3 Membrane Conventional of membrane of Type of CIP Test moment Example 1 Comp. ex. 1 week 1 weekly CIP first brew 3 out of 10 7 out of 10 second brew 2 out of 10 5 out of 10 third brew none 3 out of 10 week 3 monthly CIP first brew 1 out of 10 5 out of 10 second brew none 3 out of 10 third brew none 1 out of 10 week 5 Weekly CIP first brew 1 out of 10 5 out of 10 second brew none 3 out of 10 third brew none 1 out of 10 week 6 weekly or comparable to week 5 and on montly

[0033] The results in Table 3 show that the membrane of the present invention is less sticky than the conventional membrane during operational conditions.

EXAMPLE 3

Evaluation of Membrane Durability

[0034] The filtrations units of Example 2 were used for filtration during a time period of approximately 90 weeks, wherein 4700 brews were produces for which the mash was filtered. During this time, the conventional mash filter membranes as referred to in Comparative example 1 had a fail rate of 13% (18 out of 138), while the mash filter membranes of the present invention according to Example 1 had a fail rate of 0% (0 out of 138). Moreover, none of the membranes of the present invention showed any creases, while significant creasing was observed for the conventional filters.

[0035] After 4700 brews of about 2 hours in 90 weeks, samples of both types of mash filters membranes were analyzed for the membrane properties indicated in Table 4, using the same methods as indicated in Tables 1 and 2.

TABLE-US-00004 TABLE 4 Conventional membrane of Material property Membrane of Example 1 Comp. ex. 1 Density  1.06 g/cm.sup.3  0.98 g/cm.sup.3 Shore A hardness  70 ShA  75 ShA Tensile strength  11.2 MPa  6.3 MPa Elongation at break 234% 425% Modulus 25%  1.3  1.4 Modulus 50%  2.4  2.2 Modulus 100%  4.9  2.9 Modulus 200%  9.5  2.9 Modulus 300% n.d.  4.7 Tear resistance, maximum  51N  49N force Tear resistance, tear  24 kN/m  22 kN/m resistance Compression set  15%  59%

[0036] From Table 2, it can be concluded that, comparing both the conventional membranes with the membranes of the present invention, the membranes of the present invention have a significantly higher strength and this stays relative constant in time up till now, whereas the conventional membranes lose some of its initially already lower strength and stiffness. The tear strength of the membranes of the present invention is initially higher and this is still the case after 4700 brews and also the permanent deformation (compression set) of the test membranes is significantly less, which is better as compression set is preferred to be as low as possible for this kind of applications.