FI20215509A1

FI20215509A1 - Microcrystalline cellulose product

Info

Publication number: FI20215509A1
Application number: FI20215509A
Authority: FI
Inventors: Kari Peltonen; Kari Vanhatalo; Hannu Råmark; Sonja Päärnilä
Original assignee: Andritz Oy
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2022-10-31
Also published as: WO2022229511A1

Abstract

A microcrystalline cellulose (MCC) product is disclosed. The use of a MCC product in pharmaceutical applications, cosmetics, food and beverage applications, or any combination thereof is further disclosed.A microcrystalline cellulose (MCC) product is disclosed. The use of an MCC product in pharmaceutical applications, cosmetics, food and beverage applications, or any combination thereof is further disclosed.

Description

MICROCRYSTALLINE CELLULOSE PRODUCT

TECHNICAL FIELD

The present disclosure relates to a microcrystalline cellulose (MCC) product. The present disclosure further relates to the use of a MCC product in pharmaceutical applications, cosmetics, food and beverage applications, or any combination thereof.

BACKGROUND

Microcrystalline cellulose (MCC) is a cellu- lose product having particle-like physical characteris- tics which are totally different than those of the raw material it is produced from, chemical pulp. Chemical pulp has a fiber-like structure meaning high length/thickness ratio, in the MCC manufacturing process it is transformed to a particle-like product using an acid hydrolysis process.

The intensity of the hydrolysis process affects the product properties. The more chemical used, the longer residence time of hydrolyzed material in a reac- tor, or the higher consistency of reaction slurry, the higher the hydrolysis intensity. This means that by changing intensity of acid hydrolysis in MCC manufac- turing process, various kinds of MCC products can be — produced.

O It is a well-known fact in chemical engineering + science that mass transfer affects the efficiency of = chemical reactions. If mass transfer is insufficient, © 30 concentration gradients are formed leading to a decrease

E of the reaction rate. This can happen e.g. in an acid x hydrolysis process when MCC is manufactured. 2 Mixing phenomena level out concentration gra-

N dients inside a reactor or reactors by converting het-

N 35 erogenous material mixtures to homogenous form. This can lead to an increase in the reaction rate, e.g. in MCC acid hydrolysis, meaning more efficient production pro- cess. Because mixing is a physical unit process it will also affect the product by mechanical means.

So, in MCC manufacturing, product properties are the result of a combination of several factors (chemical charge, process concentration, time, temper- ature, mass transfer, and physical stress).

US patent 2,978,446 discloses a method for man- ufacturing MCC. In said method, acid is added to the reactor in one portion and reactor is started. No mixing during the hydrolysis reaction is mentioned. After the hydrolysis, the product is modified using strong me- chanical mixing/shear lasting 1h to create a viscous gel. US patent 7,037,405 discloses a method of producing

MCC using acids, it does not mention mixing during the acid hydrolysis process. Acid is added to the reactor in one portion. The patent teaches using a harsh me- chanical refiner after hydrolysis to produce very small

MCC particles having particle size range 1.0 - 10.0 um.

WO 02/057540 discloses a method of producing MCC using pulp material that has not been dried and mixing the reaction slurry during the hydrolysis reaction. The acid is added to reactor in one portion. US patent 2012/0135505 discloses an MCC manufacturing process where compressed cellulose raw material is hydrolyzed using acid(s). The reaction slurry is stirred during the hydrolysis procedure and the acid added to the reactor

N in one portion. The patent does not teach effect of

N mixing on the end product. US patent 4391973 discloses

S 30 an MCC process where cellulose raw material is hydro- 2 lyzed using acid(s) and the reaction mixture is stirred =E during the hydrolysis process, it does not mention the * effect of mixing on the end product. WO 2019/095024 3 discloses making MCC using 2 separate reactors. Between = 35 the reactors the pressure is reduced to atmospheric

S pressure and washing of intermediate product is performed. Acid is added to reactor 1 and to reactor 2.

No mixing mentioned during hydrolysis process.

None of the known methods show the fact that by using very short mixing during, or after hydrolysis, product properties can be adjusted. Neither do any of the known MCC manufacturing methods show split acid add- ing combination to hydrolysis system.

In view of the known processes there is a need for a renewed method to produce MCC where the product properties can be varied using simple process solutions.

SUMMARY

A microcrystalline cellulose (MCC) product is disclosed. The MCC may be formed by mixing a hydrolyzed pulp mixture with an energy dissipation of around 0.01 = 15.0 x 10% W/m? for 0.1 — 180 s and have an average particle size of 10 — 250 um. The use of a MCC product in pharmaceutical applications, cosmetics, food and beverage applications, or any combination thereof is further disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the embodiments and constitute a part of this specification, illustrate various embodiments. In the drawings: — Fig. 1 presents a schematic drawing of an em-

O bodiment of a system for producing MCC according to the < present disclosure wherein the system comprises one re-

S 30 actor.

Fig. 2 presents a schematic drawing of an em- = bodiment of a system for producing MCC according to the 2 present disclosure wherein the system comprises two re-

O actors.

S

Fig. 3 presents d-ratio values after mixing

MCC1 using different rpm’s and mixing times using a cutting-type mixer.

Fig. 4 presents particle size distribution of

MCCI1 before mixing.

Fig. 5 presents particle size distribution of

MCC1 after 15s mixing using 15000 rpm.

Fig. 6 presents d-ratio values after mixing

MCC2 using shear creating type mixer with rpm 5000 at temperature 80 °C.

DETAILED DESCRIPTION

A microcrystalline cellulose (MCC) product is disclosed. The MCC product may be produced using a method comprising: a. Acid hydrolysis of a pulp mixture in a reactor to obtain a hydrolyzed process mixture, and b. mixing the hydrolyzed process mixture to form MCC.

Figures 1 and 2 show exemplary implementations of the method using a single reactor system or a two- reactor system. In certain embodiments, mixing in this system can happen in one or several places and acid can be added to the system in one or several places. = In an initial stage of the process system,

N there is a pulp suspension which is used as raw material x to manufacture microcrystalline cellulose (MCC). In one

S 30 embodiment of the invention acid (3) used in MCC

Ir manufacturing can be added to the suspension in the

E initial stage before pulp enters a pumping vessel (2) 3 or similar. The purpose of the pumping vessel 1s to

O balance the incoming pulp suspension flow before

O 35 entering the sequential process stage. Alternatively, the pumping vessel can act as a mixing vessel if the addition of acid is performed before the suspension or pulp enters the standpipe.

The pulp used for the production of MCC may be any suitable type of bleached chemical pulp such as 5 kraft pulp, pre-hydrolyzed kraft, sulfite pulp, semichemical pulp, mechanical pulp, nonwood pulp, recovered fibres, or any combination thereof. The pulp may be produced from hardwood, softwood, grasses, straws, wastepaper, bamboo, or any combination thereof.

In certain embodiments, the consistency of the pulp before introduction in the pumping vessel may be around 2 - 50 weight-%, around 3 — 45 weight-%, or around 5 - 30 weight-%.

In certain embodiments, the consistency of the pulp before introduction in the first reactor may be around 2 - 30 weight-%, around 3 - 25 weight-%, or around 5 —- 20 weight-%, or around 8 - 15 weight-%. In one embodiment, the consistency of the pulp before introduction in the first reactor may be around 10 weight-%.

The pulp suspension (1) is fed from the pumping vessel (2) into the process line (14). A booster pump (4) is used to pump heated pulp suspension to hydrolysis reactor to maintain desired hydrolysis temperature and pressure. Process steam (5), which is used to heat the pulp to hydrolysis temperature, is fed into process line — either before or after the booster pump. In one

O embodiment of the invention acid (3) used in MCC < manufacturing process can added to process line before = 30 and/or after booster pump (4) in process line (14). 2 In one embodiment, process steam is used to a. heat the pulp suspension to around 80 -— 185 °C, or 90 - 2 175 °c, or 100 - 165 °C, or 120 - 160 °C. In one

Lo embodiment, process steam is used to heat the pulp 3 35 suspension to around 130 - 160 °C.

In certain embodiments, the acid hydrolysis of pulp to form MCC may be performed according to the methods disclosed in patent applications WO 2011/145600

Al or WO 2011/145601 Al.

The heated and acidified pulp suspension enters a 1st reactor (7) where the cellulose in the pulp suspension is hydrolysed, meaning that it is depolymerized, i.e. the degree of polymerization (DP) is decreased. During the hydrolysis process, local concentration gradients can occur leading to a decrease in reactions speeds, i.e. the efficiency of the hydrolysis. In this kind of situation, the process does not work in an optimal state and does not produce a uniform product. To increase the homogeneity of material flow, remove concentration gradients, mix chemicals better, and to increase hydrolysis efficiency and product homogeneity, pulp suspension can be mixed inside the reactor.

In one embodiment, the mixing can happen any place inside the reactor before material flow out or in a pre-mixer (6) placed before the entry point of the reactor. At the pre-mixer and in the reactor the chemical pulp fiber is not yet hydrolyzed to microcrystalline cellulose and still has the chemical and physical characteristics of cellulose or pulp. This means that cellulose does not fulfill definitions of — microcrystalline cellulose defined by Food and

O Agriculture Organization of the United Nations. < In one embodiment, the mixing occurs in the = 30 reactor (7) using mixer (8). In one embodiment, the

O process mixture is mixed in the at least one reactor

E: during the hydrolysis process. Mixing inside the reactor 2 or reactors aids in producing a homogenous process

LO mixture to improve the efficiency of the hydrolysis.

N 35 In one embodiment, the mixing can also occur

N at the output of the hydrolysis reactor or in process line after the output of reactor in mixer (9) or at the end of the process line (27) before removal of the MCC (13) in mixer (10).

In certain embodiments, the mixing in any of the aforementioned mixers may independently be described by one of the following alternatives: 1. If pulp suspension fibers have not been converted to microcrystalline cellulose (i.e. they have not been hydrolyzed) and are still at least partly in solid fiber form described by a high degree of polymerization, the mixing effect is the creation of a homogeneous mixture 2. If the hydrolysis process is already completed and the pulp has been hydrolyzed to microcrystalline cellulose a) in a chemical sense, but not necessarily in a physical sense (meaning that the pulp and/or MCC particles is still loosely attached or aggregated in fiber-like form), or b) in chemical and physical sense (meaning that the pulp is fully hydrolyzed), the effect of mixing is to disintegrate material into particle-like MCC and/or to adjust the properties of the final product such as particle size distribution.

In certain embodiments, the produced MCC may flow through process line (17) for further processing, e.g. washing, drying, and packing etc. In one — embodiment, the hydrolyzed process mixture from the 1st

O reactor is fed into a 2994 reactor for further hydrolysis. < In certain embodiments, the material flow is = 30 lead to a 2m hydrolysis reactor after exiting the 1st

O hydrolysis reactor. In one embodiment, a material flow

E: that is still at least partially in fiber form is lead 2 to a 24 hydrolysis reactor. In one embodiment, the

LO process mixture is mixed at least once between the 1st 3 35 and the 2 reactor.

In certain embodiments, the hydrolysis process continues in the 2nd hydrolysis reactor (19). The process and reactions of the 2"9 reactor is similar to that of the 18* reactor described above.

During the hydrolysis process inside the 2rd reactor, local concentration gradients can occur leading to a decrease in reactions speeds, i.e. the efficiency of the hydrolysis. In this kind of situation, the process does not work in an optimal state and does not produce a uniform product. To increase the homogeneity of material flow, remove concentration gradients, mix chemicals better, and to increase hydrolysis efficiency and product homogeneity, pulp suspension can be mixed inside the reactor.

In one embodiment, the mixing can happen in any place inside the reactor (19) using mixer (23) before material flow out. In the reactor the chemical pulp fiber is not yet hydrolyzed to microcrystalline cellulose and still has the chemical and physical characteristics of cellulose or pulp.

In certain embodiments, the mixing in any of the aforementioned mixers may independently be described by one of the following alternatives: 1. If pulp suspension fibers have not been converted to microcrystalline cellulose (i.e. they have not been hydrolyzed) and are still at least partly in — solid fiber form described by a high degree of

O polymerization, the mixing effect is the creation <t of a homogeneous mixture = 30 2. If the hydrolysis process is already completed and

O the pulp has been hydrolyzed to microcrystalline

E: cellulose a) in a chemical sense, but not 2 necessarily in a physical sense (meaning that the

DO pulp and/or MCC particles is still loosely attached

S 35 or aggregated in fiber-like form), or b) in chemical and physical sense (meaning that the pulp is fully hydrolyzed), the effect of mixing is to disintegrate material into particle-like MCC and/or to adjust the properties of the final product such as particle size distribution.

In one embodiment, the mixing can also be performed at the outflow of material from the 2nd hydrolysis reactor using a mixer (24) or in the process line directly following the reactor using a mixer (25).

In certain embodiments, mixing of the pulp or process mixture may be carried out at one or more points of the process independently selected from prior to entering the 1s* reactor, the 1st or 2m reactor, the flow out point of the 1st or 2nd reactor, at a point in the process line between the 1% and 2nd reactor, and/or the flow out point for the process.

In one embodiment, the process comprises a premixing of the process mixture or pulp prior to entering the 1st reactor and one or more additional mixing steps at points of the process independently selected from the 1st or 27d reactor, the flow out point of the 1st or 2m reactor, at a point in the process line between the 1st and 2 reactor, and/or the flow out point for the process.

In certain embodiments, acid may be added to the pulp or process mixture at one or more points of the process. In one embodiment, acid is added to the pulp — or process mixture at least in process line (14) before

O or after booster pump (4). In certain embodiments, acid < may be added to the process mixture in mixer (9) on = 30 leaving the 1st reactor and/or prior to entering the 2nd 9 reactor (15). In one embodiment, acid is added to the = process mixture between the 1s* and 27 reactor. 2 In one embodiment, process steam (5), which is

LO used to heat the pulp to hydrolysis temperature, is fed

N 35 into process line either before or after the booster

N pump. In one embodiment, additional process steam (16)

is fed in the process line between the 1st and 2nd reactor.

In one embodiment, the added steam heats the process mixture to a temperature of around 80 - 185 °C, or 90 - 175 °C, or 100 — 165 °C, or 120 — 160 °C. In one embodiment, added steam is used to heat the pulp suspension to around 130 - 160 °C

Acid is added to the process mixture to hydrolyze the pulp into microcrystalline cellulose. In one embodiment, the acid is selected from the group consisting of mineral acids and organic acids. The acid used may be a mineral acid. In one embodiment, the acid is selected from the group consisting of sulphuric acid, hydrochloric acid, nitric acid, or any mixture thereof.

In one embodiment, acid is added to the process mixture in an amount that is 0.2 - 10 weight-% relative to the amount of solids.

High shear mixers used in mixing applications in pulp and paper industry have the ability to disrupt the fiber network that is formed when pulp consistency increases to the level 6 — 15 %, more typically pulp is treated in consistency range 8 - 13 %. For example at 10% consistency the pulp forms groups of fibers, called flocs, the size of which is in the range 2 - 20 mm. A single fiber floc consists of tens of thousands of fi- bers. Disruption of the fiber network is essential for — treating single fibers or micro flocs or to get chemical

O in contact with a fiber. <t In one embodiment, mixing is performed with an = 30 energy dissipation of around 0.01 — 15.0 x 10° W/m3. In

O certain embodiments, the mixing may be performed using = low intensity 0.01 — 1.0 x 10% W/m? or high intensity 2 1.0 — 15.0 x 108 W/m3. In one embodiment, mixing is

Lo performed with an energy dissipation of around 1.0 — 5.0 3 35 x 10% W/m.

In one embodiment, the mixing time is 0.1 — 180 s. In certain embodiments, the mixing time is 0.1 - 30.0 s, or 0.1 — 10.0 s, or 0.1 — 5.0 s.

In one embodiment, the process mixture is mixed thoroughly in the 18* reactor to achieve complete hydrolysis of the cellulose in the pulp. Once the hydrolysis is completed, the hydrolyzed pulp is removed from the 15% reactor and mixed briefly to homogenize the product MCC. In one embodiment, mixing is performed immediately on removing the hydrolyzed process mixture from the reactor. In one embodiment, additional mixings are performed after removing the process mixture from the reactor.

In certain embodiments, the MCC is formed in a semi-batch or continuous manner. In certain embodiments, the MCC is formed in a continuous manner.

In one embodiment, the hydrolyzed process mixture is removed from the 1st reactor and mixed briefly to provide a thoroughly mixed intermediate process mixture that is fed into process a line (17). In one embodiment, the feeding of the intermediate process mixture is controlled by a valve (12).

In one embodiment, the process mixture may be mixed immediately prior to removing from the process line using a mixer (10, 25) to produce an MCC product with the desired characteristics. — After removal from the process line, the MCC

O product may be subjected to processing steps such as <t drying. = 30 In certain embodiments, the flow of the process

O mixture in the process line and/or between the reactors = may be controlled using pumps (4, 11, 26) and valves 2 (12, 18).

LO The method of the present disclosure has the

N 35 added utility that it enables production of MCC with

N small particle size and a narrow size distribution.

In one embodiment, the MCC product may be produced using a system that implements the method described above. The system for producing MCC comprises at least one reactor. In one embodiment, each reactor in the system comprises at least one mixer.

In one embodiment, the system comprises a 1st reactor in which a hydrolysis process is carried out.

In certain embodiments, the system comprises at least a 1st and a 2rd reactor. Pulp is fed into the system from a pumping vessel (2) connected to the 1st reactor by a process line (14).

In one embodiment, the process line comprises means for feeding acid into the pulp. In one embodiment, the process line comprises means for feeding acid into the pulp and means for feeding steam into the pulp. In one embodiment, the system comprises at least one pump for transporting the process mixture. In one embodiment, the process line also comprises a mixer (6) for mixing the pulp and acid to form a homogenous process mixture.

In one embodiment, the system comprises at least one mixer outside the at least one reactors.

From the process line, the process mixture is fed into the 1st reactor. After a pre-determined residence time in the 1st reactor, the process mixture is removed from the 15* reactor. In one embodiment, the — process mixture is mixed briefly after removal from the

O 1s* reactor. In one embodiment, the system comprises at < least one mixer at the exit of each of the at least one

S 30 reactor.

In one embodiment, the process mixture removed = from the 1s8* reactor is mixed briefly immediately on 2 removal from the 1st reactor after to form a MCC

LO composition which it is passed into a second process

N 35 line (17). In certain embodiments, the second process

N line comprises a pump and/or a valve to control the flow of the MCC composition from the 1st reactor. In one embodiment, the second process line comprises a mixer (10) that mixes the MCC composition before it is removed from the system (MCCour, 13). In one embodiment, the system comprises at least one mixer in the process line.

In one embodiment, the system for producing MCC comprises a second reactor (19) connected to the 1st reactor by a second process line (17). In certain embodiments, the second process line comprises a pump and/or a valve to control the flow of the process mixture from the 1st reactor. In certain embodiments, the second process line comprises means for adding steam (16) to the process mixture to heat the process mixture before the 214 reactor. In one embodiment, the second process line comprises a means for adding acid (15) to the process mixture.

In one embodiment, acid is added to the process mixture between the 1%t and 2" reactor. In one embodiment, acid (20) can be added to the process mixture in connection with mixing the process mixture leaving the 15* reactor. In one embodiment, the second process line comprises a valve (12) to control the flow of process mixture to the 2"4 reactor. In one embodiment, the second process line comprises a mixer (10) to briefly mix the process mixture immediately before entering the 2"4 reactor. In one embodiment, the system — comprises a means for adding acid to the process mixture

O and/or a process line. < In the 2nd reactor, the hydrolysis of the = 30 cellulose contained in the process mixture is completed

O to form a MCC composition. In one embodiment, the 2nd

E reactor comprises a mixer (23) to ensure thorough mixing 2 of the process mixture and complete hydrolysis of the

LO cellulose. After a pre-determined residence time in the

N 35 24 reactor, the formed MCC composition is removed. In

N one embodiment, the MCC composition is mixed briefly immediately on removal from the 27 reactor and fed into a third process line (21). In one embodiment, the third process line comprises a mixer (25) that mixes the process mixture before it is removed from the system (22). In certain embodiments, the third process line comprises a pump and/or a valve to control the flow of

MCC product from the system.

In certain embodiments, the system is operated in a semi-batch or continuous manner. In certain embodiments, the system is operated in a continuous manner.

Once the MCC product has been removed from the system, any final treatments may be applied to it. Non- limiting examples of such treatments are removing the water from the MCC product, drying the MCC product and/or sorting the MCC product formed in the process or system by particle size.

The system of the present disclosure has the added utility that it enables production of a MCC product with small particle size and a narrow size distribution.

Using the method or system of the present disclosure it is possible to produce MCC with an even size distribution and small particle size. By adjusting the various mixing steps, it is possible to adjust the particle size of the produced MCC to a desired value and — provide an MCC product with a narrow and even sized

O distribution. < MCC obtainable by the above method is disclosed = 30 herein. MCC obtainable by the above system using the 9 above method is disclosed herein.

E In one embodiment, the MCC formed using the 2 method described herein may be formed by mixing a

LO hydrolyzed pulp mixture with an energy dissipation of

N 35 around 0.01 — 15.0 x 109 W/m? for 0.1 — 180 s and has an

N average particle size of 10 - 250 um.

In certain embodiments, the MCC product is formed by mixing a pulp mixture with an energy dissipation of 0.01 — 1.0 x 106 W/m? or 1.0 — 15.0 x 10¢

W/m3. In certain embodiments, the MCC product is formed by mixing a pulp mixture with an energy dissipation of 1.0 — 5.0 x 108 W/m3.

In certain embodiments, the MCC product disclosed herein is formed by mixing a pulp mixture for 0.1 — 30.0 s, or 0.1 — 10.0 s, or 0.1 — 5.0 s.

The MCC product formed using the method described herein or in the system described herein may have an average particle size of approximately 10 - 250 pm. In certain embodiments, the MC has an average particle size of 20 - 200 pm, 25 - 150 um, 30 — 100 um, 35 - 75 pm.

In certain embodiments, the dl0 of the MCC formed may be less than 30 pm, d50 may be less than 60 pm, and 4d90 may be less than 300 pm. In certain embodiments, the MCC has a dl0 of less than 28 um, or less than 26 um, or less than 24 um, or less than 22 pm, or less than 20 pm, a d50 of less than 55 pm, or less than 50 pm, or less than 45 pm, or less than 40 um, or less than 35 um, or less than 30 pm, and a d90 of less than 275 pm, or less than 250 jm, or less than 225 pm, or less than 200 um, or less than 175 um.

In one embodiment, the d-ratio of the MCC — formed may be in the range of 1.0 — 6.0. In certain

O embodiments, the d-ratio of the MCC is less than 6.0, < or less than 5.5., or less than 5.0, or less than 4.5, = 30 or less than 4.0.

O By varying the mixing speed and mixing time of

E: the one or more mixings in the method described, it is 2 possible to control both size and size distribution of

LO the MCC formed in the process.

N 35 D-values (dl0, d50, and 490) indicate how many

N percent (10%, 50%, or 90%) of the particle are over certain micrometer size. d-ratio means SIN and it describes the wideness of the particle size distribution. The larger the d-ratio, the wider the size distribution. Usually sharp narrow particle size distributions are desired because it gives more precise properties to certain products.

In one embodiment, the MCC product of the present disclosure may be used in pharmaceutical applications, cosmetics, food and beverage applications, or any combination thereof is further disclosed.

In certain embodiments, the MCC product is formed in a semi-batch or continuous manner. In certain embodiments, the MCC product is formed in a continuous manner.

The MCC product described in the current specification has the added utility of having both a small particle size and a narrow size distribution compared to MCC produced with other methods.

EXAMPLES

Reference will now be made in detail to various embodiments.

The description below discloses some embodiments in such a detail that a person skilled in the art is able to utilize the embodiments based on the — disclosure. Not all steps or features of the embodiments

O are discussed in detail, as many of the steps or features + will be obvious for the person skilled in the art based = 30 on this specification.

O The following examples describe how mixing z affects MCC product properties when it is done during o or after the hydrolysis reaction. Definitions: d-values 3 (d10, d50, and d90) indicate how many percent (10%, 50%,

N 35 or 90%) of the particles are under certain micrometer

N size. d-ratio means SA and it describes wideness of particle size distribution. A larger the d-ratio indicates a wider size distribution. Usually sharp narrow particle size distributions are desired because it gives more precise properties to certain products.

Example 1 - Effect of mixing on MCC particle size distribution after hydrolysis

Two microcrystalline cellulose products, MCC1 and MCC2, were prepared using hardwood base chemical pulp as raw material. Table 1 shows particle size d-values and d-ratio of these products.

Table 1. MCC properties (undried qualities, measured using Malvern Mastersize 2000 equipment) d10 d50 d90 d-ratio (um) — (um) (um)

MCC1 16.0 55.2 359.7 6.2

MCC2 15.4 50.8 280.5 5.2

Average particle size of MCCl and MCC2 were 55.2um and 50.8um respectively. In the acid hydrolysis process, mild reaction conditions were used, so d90- values remained on a high level of 359.7 (MCC1) and 280.5 (MCC2). The d-ratios were: MCC1 6.2 and MCC? 5.2.

So, both products had very wide particle size distribution. Both products were washed to neutral pH — after hydrolysis.

O Mixing experiments were performed on the MCC <t 25 products in order to adjust the average particle size = and especially the width of the particle size

O distribution to achieve much lower d-ratios. = High shear mixer was used for mixing MCC1 after 2 the hydrolysis process, using 5% consistency. Mixer rpm

O 30 value was changed and mixing times from bs to 635 s were 3 used.

Figure 3 presents d-ratio values after mixing

MCC1 using different rpm's and mixing times. The mixer used was a cutting type mixer. Fig. 3 shows that even after short 5 - 15 second mixings, d-ratio values decrease around 40%. Using high rpm's decreases the

MCC's d90-value from 359.7um to 230.9jm after 5 seconds and to 178.7um after 15 seconds. This means that the portion of bigger particles decreases, d-ratio decreases and particle size distribution becomes narrower. Fig. 4 shows particle size distribution of MCC1 before mixing, and Fig. 5. after 15 seconds mixing.

The effect of mixing effect on size distribution is evident when using short mixing after hydrolysis. Short mixing removes distribution tri-modal shape converting it to more even distribution form. At the same time average particle size decreases from 55.2pm to 42.3pm.

Figure 6 shows the effect of mixing on MCC2.

Used mixing consistency was 10%, MCC-water slurry was heated to 80°C before mixing and 5000rpm was used. Used mixer device was more shear creating mixer than in the previous case.

Figure 6 shows that short 15 seconds time is enough to decrease d-ratio 5.2 to 3.2, which is almost 40% decrease. The d90-value, which depicts portion of bigger particle is 280.5um before mixing and after 15s it is decreased to 124.9m. At the same time average

N particle size is decreased from 50.8pm to 34.9].

N

S 30 Fxample 2. Effect of mixing during hydrolysis 2 on MCC particle size distribution i

In order to see the effect of mixing during 3 acid hydrolysis in MCC manufacturing, a Lödige DVT5 = 35 reactor was used. The reactor was equipped with a

S heating jacket and steam was used as the heating medium.

Lödige's reactor chamber diameter was 200mm and height

230mm making reactor volume 7.2dm3. From the control unit it was possible to adjust the rpm's of the chopper (diameter 50mm, max. rpm 3000, max. achievable peripheral speed 7.9 m/s) and mixing blades (diameter 190mm, max. rpm 250, max. achievable peripheral speed 2.5 m/s). The chopper mixer was a fluidizing mixer used to provide high shear forces to the reaction slurry whereas the blades were intended for stirring. 10% reaction consistency, 1.5% sulfuric acid dosage, 150 °C temperature, 30 P-factor were used in MCC manufacturing.

Table 2 shows resulted particle size of three test points.

Table 2. Results of MCC manufacturing when different mixing intensities were used during acid hydrolysis. boint P-factor Ming Pig mr ve d10 d50 d90 — d-ratio (rpm) (rpm) (um) (um) (um) 1 30 1 49 0 10.3 29.5 162.1 5.1 2 30 2 124 1300 9.1 23.1 90.2 3.5 330 3 20 2900 86 217 76.0 31

It is seen from Table 2. that by increasing mixing intensity, the produced particle size is decreased, the particle size distribution becomes narrower, and the d- ratios decrease.

It is obvious to a person skilled in the art that with the advancement of technology, the basic idea = may be implemented in various ways. The embodiments are < thus not limited to the examples described above; x 25 instead they may vary within the scope of the claims. oO The embodiments described hereinbefore may be 2 used in any combination with each other. Several of the a embodiments may be combined together to form a further 2 embodiment. A MCC product, or a use, disclosed herein,

LO 30 may comprise at least one of the embodiments described

N hereinbefore. It will be understood that the benefits

N and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to 'an' item refers to one or more of those items. The term “comprising” is used in this specification to mean including the feature(s) or act(s) followed thereafter, without excluding the presence of one or more additional features or acts.

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Claims

1. Microcrystalline cellulose (MCC) product, wherein the MCC the MCC is formed by mixing a hydrolyzed pulp mixture with an energy dissipation of around 0.01 —- 15.0 x 10% W/m? for 0.1 - 180 s and has an average particle size of 10 —- 250 um.

2. The MCC product of claim 1, wherein the product is formed by mixing a pulp mixture with an energy dissipation of 0.01 — 1.0 x 106 W/m? or 1.0 — 15.0 x 10¢

W/m.

3. The MCC product of any of the preceding claims, wherein the product is formed by mixing a pulp mixture with an energy dissipation of 1.0 - 5.0 x 106

W/m.

4. The MCC product of any of the preceding claims, wherein the product is formed by mixing a pulp mixture for 0.1 - 30.0 s, or 0.1 — 10.0 s, or 0.1 — 5.0 s.

5. The MCC product of any of the preceding claims, wherein the MCC has an average particle size of 20 — 200 um, 25 - 150 pm, 30 — 100 um, 35 - 75 um.

6. The MCC product of any of the preceding claims, wherein the MCC has a d10 of less than 30 pum.

7. The MCC product of any of the preceding claims, wherein the MCC has a dl0 of less than 28 num, or less than 26 pm, or less than 24 um, or less than 22 — pm, or less than 20 pm.

O

8. The MCC product of any of the preceding < claims, wherein the MCC has a 450 of less than 60 um. = 30

9. The MCC product of any of the preceding O claims, wherein the MCC has a d50 of less than 55 pm, E or less than 50 pm, or less than 45 um, or less than 40 o pm, or less than 35 pm, or less than 30 um. 3

10. The MCC product of any of the preceding N 35 claims, wherein the MCC has a 490 of less than 300 um. N

11. The MCC product of any of the preceding claims, wherein the MCC has a d90 of less than 275 pm,

or less than 250 pm, or less than 225 um, or less than 200 pm, or less than 175 pm.

12. The MCC product of any of the preceding claims, wherein the d-ratio of the MCC is in the range

1.0 — 6.0.

13. The MCC product of any of the preceding claims, wherein the d-ratio of the MCC is less than 6.0, or less than 5.5., or less than 5.0, or less than 4.5, or less than 4.0.

14. The MCC product of any of the preceding claims, wherein the MCC product is formed in a continuous manner.

15. Use of the MCC product of any of the preceding claims in pharmaceutical applications, cosmetics, food and beverage applications, or any combination thereof. N O N < <Q oO O I jami a o O O 0 N O N