WO2012076933A1 - Modified cellulose pulps, a method of high pressure processing for preparing same and uses thereof - Google Patents

Modified cellulose pulps, a method of high pressure processing for preparing same and uses thereof Download PDF

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Publication number
WO2012076933A1
WO2012076933A1 PCT/IB2010/055737 IB2010055737W WO2012076933A1 WO 2012076933 A1 WO2012076933 A1 WO 2012076933A1 IB 2010055737 W IB2010055737 W IB 2010055737W WO 2012076933 A1 WO2012076933 A1 WO 2012076933A1
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cellulose
pulps
pulp
properties
hydrostatic pressure
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PCT/IB2010/055737
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French (fr)
Portuguese (pt)
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Dmitry Victorovitch Evtyugin
Jorge Manuel Alexandre Saraiva
Andreia Filipa Bastos Figueiredo Dos Santos
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Universidade De Aveiro
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    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21CPRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/001Modification of pulp properties
    • D21C9/007Modification of pulp properties by mechanical or physical means
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21BFIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00Fibrous raw materials or their mechanical treatment
    • D21B1/04Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/30Defibrating by other means
    • D21B1/36Explosive disintegration by sudden pressure reduction
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H11/00Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
    • D21H11/16Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment

Definitions

  • the present invention relates to the hydrostatic high pressure pulp processing to modify its properties, which may have several applications.
  • This type of processing allows, among other effects, to incorporate water molecules tightly bound to the cellulose structure, conferring different and unique properties to the pulp, which may have applications both in the production of paper with improved and different properties and in obtaining better products derived from the chemical modification of cellulose.
  • the invention provides a method of modifying the properties of cellulosic pulps by cold / hot processing by high hydrostatic pressure (between 100-1000 MPa, but may be higher) at temperatures between 0 and 100 ° C for up to 75 minutes (which may be longer), applicable to any type of pulp with a consistency between 0.1 and 40%, preferably in aqueous medium, but not only.
  • This technique which currently operates at pressures between 100 and 1000 MPa, has been used commercially for modify texture and control microbial and enzymatic activity in foods without changing their nutritional and organoleptic properties.
  • Cellulose is the most abundant polymer in nature and can be used in its natural state or after chemical modification in a wide range of applications.
  • Wood is one of the main industrial sources of pulp, which can be used as cellulose pulp for the paper industry or as a raw material for the chemical industry.
  • cellulose undergoes structural rearrangements at the level of the molecules present in the fibrils and in the zones of interfibrillary aggregation, causing a series of changes in their physicochemical properties. .
  • the surface of the cellulosic fibers collapses, with a substantial decrease in swelling capacity and a loss of flexibility.
  • the present invention is directed to the modification of cellulosic pulps through hydrostatic high pressure processing and offers numerous potentials not only for the pulp and paper industry, but also for those industries that use cellulose as a feedstock in modification reactions to obtaining new cellulose-based products, such as microcrystalline cellulose production.
  • High hydrostatic pressure treatment of the pulps promotes the addition of cellulose crystallites by cocrystallization and partial recrystallization of the paracrystalline domains on the surface of the elemental fibrils. This phenomenon is responsible for increasing the average crystallite width (parameter d002, Table 1 and Figure 1). The re ⁇ ordering of segments paracrystalline surface of the elementary fibrils causes an increase in the crystallinity degree of cellulose chains.
  • hydrostatic high pressure processing causes the pastes to hydrate, forcing the incorporation of water molecules that are tightly bound to the amorphous and inaccessible regions of the cellulose structure and which are removed only at temperatures above 300 ° C.
  • the hydration of the pulps promoted by the high hydrostatic pressure causes the fibers to recover some of their swelling capacity, leading to the reduction of the effects of hornification on dry pulps and giving greater flexibility and elasticity to the fibers. No other process can cause this effect, which is due to the particularity of the way hydrostatic high-pressure technology operates, namely the high physical forces it exerts on processed products.
  • hydrostatic high pressure treatment extends the areas of use of dried pulps (including recycled pulps) and alters the properties of the never dried pulps.
  • hydrostatic high pressure processing yields new products such as microcrystalline cellulose, providing not only products with different particle size but also with a higher degree of crystallinity of the cellulose, with applications, for example as a raw material for the paper industry or excipient in the chemical, food and pharmaceutical industries.
  • the cellulosic pulp modification method object of this invention and described below can be applied to dry / never dry pulps, whether or not refined.
  • Hydrostatic high pressure processing Prior to treatment by high hydrostatic pressure, the cellulosic pastes are swollen in water for 0.5-24h, preferably under moderate agitation, to obtain suspensions of 0.1-40.0% consistency. After swelling, slurry suspensions are processed cold or hot under high hydrostatic pressure (between 100-1000 MPa, but may be higher) at temperatures between 0 and 100 ° C for up to 75 minutes (and may be higher). Hydrostatic high pressure processing can be performed with pastes in containers of varying size and geometry or by mass.
  • High pressure processing is applicable to any type of pulp having a consistency between 0.1 and 40.0%, preferably in aqueous medium, but not only.
  • the steps for this modification to take place involve:
  • Step I swelling of the cellulose pulp in water for 0,5-24h, preferably under mild agitation, to obtain suspensions of varying consistencies;
  • Step 2 After swelling, the suspension folders are processed by cold or hot high hydrostatic pressure (between 100-1000 MPa, but may be higher) at temperatures between 0 and 100 ° C for up to 75 minutes (can be more than ).
  • cold or hot high hydrostatic pressure between 100-1000 MPa, but may be higher
  • the treatment by high hydrostatic pressure of the pulps promotes the increase in the size of the cellulose crystallites through the cocrystallization and partial recrystallization of the paracrystalline domains on the surface of the elemental fibrils, causing the increase of the average cellulose crystallite width (parameter d002). increasing its degree of crystallinity.
  • forced hydration caused by High hydrostatic pressure treatments promote the incorporation of water molecules that are tightly bound to the amorphous regions of cellulose, increasing their accessibility for interaction with chemical reagents.
  • the structural changes suffered by the high pressure treated pulp make it present larger crystallites, with higher degree of crystallinity, and its fibers have a higher water absorption capacity, as well as flexibility.
  • the pulp After high hydrostatic pressure processing and drying, the pulp is swollen in water (at varying concentrations, typically 5% w / w). Acid hydrolysis occurs under reflux in the presence of dilute sulfuric acid with a concentration between 1.0 and 2.0 M, preferably 1.8 M, over a period of 0.5-5h. After the reaction and cooling, the mixture is filtered and washed with distilled water to a paste with a pH close to 7. Then the paste is oven dried at 105 ° C to constant weight.
  • the present invention proposes a process of modifying the properties of cellulose pulps by hydrostatic high pressure processing, applicable to any type of pulp, preferably in aqueous medium, but not only, with a consistency between 0.1 and 40.0%.
  • the pulp thus treated undergoes structural changes in cellulose (increased average crystallite width), increased accessibility of amorphous cellulose and incorporation of cellulose-bound water molecules, which improves the hydration of the pulp.
  • the processing of previously dried pastes restores their swelling capacity, reducing hornification problems. Structural changes in cellulose increase the intrinsic strength of the fiber, and hydration gives it flexibility, elasticity and binding capacity, improving its physical properties without decreasing the hand index.
  • the invention makes it possible to produce pulps with different properties for various applications, such as in the production of paper with different and improved characteristics, in improved cellulose chemical modification reactions as well as for other applications.
  • the unprecedented results achieved with the high pressure processing of cellulosic pulps make it possible for this invention to be applied:
  • step b) occurs at temperatures between 0-100 ° C for a time period ranging from 1-75 minutes.
  • the process is applicable to any cellulose pulp having a consistency in the range 0.1-40.0%, and is further applicable to dried or never dried pulps, whether or not refined.
  • the present invention further relates to modified cellulosic pastes which are obtained by the process described above.
  • the cellulosic pulps of the present invention are used as paper pulps or for the manufacture of products for the chemical, food, pharmaceutical and biotechnology industries.
  • Table 1 shows the parameters of the cellulose crystal lattice of both pastes, before and after treatment by high hydrostatic pressure.
  • Parameters a and b correspond to the unit cell size of axes a and b shown in Figure 1, respectively;
  • c represents the average crystallite height,
  • represents the monoclinic angle formed and doo2 the average crystallite width in the 002 plane.
  • the average crystallite width increases with high hydrostatic pressure processing, this effect being more significant for kraft pulp. .
  • Table 1 Comparison of the parameters of the cellulose crystal lattice in kraft and sulfite pulps, processed and processed by high hydrostatic pressure.
  • Table 2 shows the changes in the crystalline fraction of the cellulose present in the acid and kraft sulfite pastes, before and after treatment by high hydrostatic pressure, showing the increase in the degree of crystallinity, crystallinity index, and crystallinity parameter. pulp, caused by high hydrostatic pressure processing.
  • the increase in the degree of crystallinity may range from 1.0 to 7.0% (determined by X-ray diffraction).
  • Table 3 shows the effect of the drying step on the degree of hornification of a paste, and processing by high hydrostatic pressure reduces the hornification of dry paste to 140 ° C (temperature at which drying occurs in the paper industry), to values close to those shown by air-dried pulp.
  • this value is overestimated because hornification is calculated by comparing the water absorption capacity of a never dry and dry pulp and in this case it is not possible to account for water which after processing at high hydrostatic pressure is strongly bound to the cellulose structure and which can only be released from cellulose at very high temperatures, as mentioned above.
  • the reduction of the occurrence of the hornification effect of the pulp of the pulp processed by high hydrostatic pressure will be even greater than the value presented.
  • Table 3 Effects of different drying conditions and high hydrostatic pressure treatment on the hornification of a sulphite paste.
  • Figure 2 shows the mechanical behavior of paper sheets made from a dry acid sulphite pulp, with and without high hydrostatic pressure treatment. It is evident that high pressure processing increases the mechanical strength properties (tensile strength, tearing, bursting and zero span traction), as a result of the incorporation of water molecules tightly bound to the cellulose structure, which in addition to giving greater flexibility to the fibers, cause the effects of hornification to diminish. After treatment at high hydrostatic pressure it is possible to obtain sheets of paper with increased mechanical strength properties. Increases in tensile strength of 20-40%, burst strength of 40-60% and zero-tensile strength of 10-20% were observed. Regarding the tear strength, the increase increased from 80 to 300%.
  • Hydrostatic high pressure processing allows for chemical hydrolysis of cellulose faster and also more extensively, resulting in higher amounts of hydrolyzed cellulose.
  • Table 4 gives an example of the results obtained for the degree of crystallinity and mean crystallite width, d 0 02, of the cellulose after hydrolysis. These two parameters increase with high hydrostatic pressure preprocessing.
  • Table 4 Comparison of mean crystallite width, d002, and degree of crystallinity, GC, of cellulose present in a pulp after hydrolysis.
  • Figure 1 shows the X-ray diffractogram of the acid sulphite paste, with the representation of the respective amorphous and crystalline halos. Projection of the cellulose unit cell with its dimensions and network plans.
  • Figure 2 shows the mechanical behavior of paper sheets produced from a dry acid sulfite paste at 140 ° C, with and without treatment by high hydrostatic pressure.

Abstract

The present invention relates to a method for modifying the properties of cellulose pulps. Said method consists of modifying the properties of cellulose pulps by means of cold/hot processing with the application of high hydrostatic pressure (100-1000 MPa) at temperatures between 0-100°C for a time period of between 1-75 minutes (or possibly longer). Said method can be used for any type of cellulose pulp, preferably in aqueous medium, with a consistency in the range of 0.1-40.0%. In treated pulps, the cellulose undergoes structural changes and amorphous cellulose accessibility increases. Said method improves pulp hydration due to the incorporation of water molecules which bind strongly to the cellulose. When previously dried pulps are processed, the swelling capability of said pulps is restored and problems relating to hornification are reduced. The structural changes that occur to the cellulose increase intrinsic fibre strength, and the hydration that occurs improves fibre flexibility, elasticity and bonding ability. The physical properties of the processed pulps are significantly improved, without decreasing the bulk of same. Consequently, it is possible to produce pulps with modified and improved properties, for various uses, particularly as raw material for the paper industry or as an excipient for the chemical, food and pharmaceutical industries.

Description

D E S C R I Ç Ã O  DESCRIPTION
"PASTAS CELULÓSICAS MODIFICADAS, MÉTODO DE PREPARAÇÃO POR PROCESSAMENTO POR ALTA PRESSÃO E RESPECTIVAS APLICAÇÕES" "MODIFIED CELLULIC FOLDERS, METHOD OF PREPARATION FOR HIGH PRESSURE PROCESSING AND THEIR APPLICATIONS"
Domínio da Invenção Field of the Invention
A presente invenção diz respeito ao processamento de pastas celulósicas por alta pressão hidrostática para modificação das suas propriedades, o que poderá ter diversas aplicações .  The present invention relates to the hydrostatic high pressure pulp processing to modify its properties, which may have several applications.
Este tipo de processamento permite, entre outros efeitos, incorporar moléculas de água fortemente ligadas à estrutura da celulose, conferindo propriedades diferentes e únicas às pastas celulósicas, que podem ter aplicações quer na produção de papel com propriedades melhoradas e diferentes, quer na obtenção melhorada de produtos derivados da modificação química da celulose.  This type of processing allows, among other effects, to incorporate water molecules tightly bound to the cellulose structure, conferring different and unique properties to the pulp, which may have applications both in the production of paper with improved and different properties and in obtaining better products derived from the chemical modification of cellulose.
Concretamente, o invento apresenta um método que consiste na modificação das propriedades de pastas celulósicas através do processamento a frio/quente por alta pressão hidrostática (entre 100-1000 MPa, mas podendo ser superior), a temperaturas entre 0 e 100°C durante até 75 minutos (podendo ser superior), aplicável a qualquer tipo de pastas celulósicas com consistência entre 0,1 e 40%, preferivelmente em meio aquoso, mas não só.  Specifically, the invention provides a method of modifying the properties of cellulosic pulps by cold / hot processing by high hydrostatic pressure (between 100-1000 MPa, but may be higher) at temperatures between 0 and 100 ° C for up to 75 minutes (which may be longer), applicable to any type of pulp with a consistency between 0.1 and 40%, preferably in aqueous medium, but not only.
Estado da técnica State of the art
A tecnologia de alta pressão tem vindo a ser aplicada na produção de materiais compósitos, cerâmicos e metálicos (US 3,286,337), plásticos e diamante artificial, sendo na actualidade uma tecnologia em expansão que atraiu a atenção da indústria alimentar para processar e preservar alimentos (US 2004/0058041; US 3,407,721; US 5,213,029; US 6,217,435 BI; US 5, 932, 272) .  High pressure technology has been applied in the production of composite, ceramic and metallic materials (US 3,286,337), plastics and artificial diamond, and is currently a booming technology that has attracted the attention of the food industry to process and preserve food (US 2004/0058041; US 3,407,721; US 5,213,029; US 6,217,435 BI; US 5,932,272).
Esta técnica, que opera correntemente a pressões entre 100 e 1000 MPa, tem vindo a ser utilizada comercialmente para modificar a textura e controlar a actividade microbiana e enzimática em alimentos, sem alterar as suas propriedades nutricionais e organolépticas . This technique, which currently operates at pressures between 100 and 1000 MPa, has been used commercially for modify texture and control microbial and enzymatic activity in foods without changing their nutritional and organoleptic properties.
A celulose é o polímero mais abundante na Natureza, podendo ser usado no seu estado natural ou após modificação química num vasto leque de aplicações. A madeira é uma das principais fontes industriais de celulose, que pode ser utilizada sob a forma de pasta celulósica para a indústria papeleira ou como matéria-prima para a indústria química. No entanto, na indústria papeleira, durante o processo de secagem da pasta, a celulose sofre rearranjos estruturais ao nível das moléculas presentes nas fibrilas e nas zonas de agregação interfibrilar , fazendo com que ocorram um conjunto de alterações ao nível das suas propriedades físico-químicas . Como consequência, a superfície das fibras celulósicas colapsa, ocorrendo uma diminuição substancial da sua capacidade de intumescimento e uma perda de flexibilidade. Este fenómeno é conhecido como hornificação e é responsável por deteriorar a acessibilidade da celulose face à água e outros reagentes químicos, assim como por diminuir drasticamente as propriedades papeleiras das pastas e fibras recicladas. Uma parte destas alterações são irreversíveis, isto é, as propriedades iniciais de intumescimento das fibras não são recuperadas após o seu re-humedecimento e refinação. Este é um dos principais problemas que ocorrem na química e tecnologia da celulose, e que não se encontra ainda resolvido, causando custos significativos à indústria papeleira e a outras indústrias. A alteração das propriedades das pastas celulósicas pelo método proposto no invento, nomeadamente pelo efeito de hidratação (incorporação de moléculas de água) tem também aplicações ao nível da reactividade química da mesma, com elevado potencial para inúmeras aplicações.  Cellulose is the most abundant polymer in nature and can be used in its natural state or after chemical modification in a wide range of applications. Wood is one of the main industrial sources of pulp, which can be used as cellulose pulp for the paper industry or as a raw material for the chemical industry. However, in the paper industry, during the pulp drying process, cellulose undergoes structural rearrangements at the level of the molecules present in the fibrils and in the zones of interfibrillary aggregation, causing a series of changes in their physicochemical properties. . As a result, the surface of the cellulosic fibers collapses, with a substantial decrease in swelling capacity and a loss of flexibility. This phenomenon is known as hornification and is responsible for deteriorating the accessibility of cellulose to water and other chemical reagents, as well as drastically decreasing the paper properties of pulp and recycled fibers. Some of these changes are irreversible, ie the initial swelling properties of the fibers are not recovered after rewetting and refining. This is one of the major problems that occur in pulp chemistry and technology, and is not yet resolved, causing significant costs to the paper industry and other industries. The alteration of the properties of cellulosic pulps by the method proposed in the invention, namely by the hydration effect (incorporation of water molecules) also has applications in terms of chemical reactivity of the same, with high potential for numerous applications.
Descrição A presente invenção tem como objectivo a modificação das pastas celulósicas através do processamento por alta pressão hidrostática e oferece inúmeras potencialidades não só para a indústria da pasta e papel, mas também para aquelas indústrias que utilizam a celulose como matéria- prima em reacções de modificação para a obtenção de novos produtos baseados em celulose, como a produção de celulose microcristalina . description The present invention is directed to the modification of cellulosic pulps through hydrostatic high pressure processing and offers numerous potentials not only for the pulp and paper industry, but also for those industries that use cellulose as a feedstock in modification reactions to obtaining new cellulose-based products, such as microcrystalline cellulose production.
0 tratamento por alta pressão hidrostática das pastas promove o acréscimo dos cristalitos de celulose, através da cocristalização e recristalização parcial dos domínios paracristalinos na superfície das fibrilas elementares. Este fenómeno é responsável pelo aumento da largura média de cristalito (parâmetro d002, Tabela 1 e Figura 1) . A re¬ ordenação dos segmentos paracristalinos da superfície das fibrilas elementares causa o aumento do grau de cristalinidade das cadeias de celulose. High hydrostatic pressure treatment of the pulps promotes the addition of cellulose crystallites by cocrystallization and partial recrystallization of the paracrystalline domains on the surface of the elemental fibrils. This phenomenon is responsible for increasing the average crystallite width (parameter d002, Table 1 and Figure 1). The re ¬ ordering of segments paracrystalline surface of the elementary fibrils causes an increase in the crystallinity degree of cellulose chains.
Simultaneamente, o processamento por alta pressão hidrostática provoca a hidratação das pastas, forçando a incorporação de moléculas de água que ficam fortemente ligadas às regiões amorfas e inacessíveis da estrutura da celulose, e que são removidas apenas a temperaturas superiores a 300°C. Desta forma, a hidratação das pastas promovida pela alta pressão hidrostática faz com que as fibras recuperem alguma da sua capacidade de intumescimento, originando a diminuição dos efeitos da hornificação nas pastas secas e conferindo maior flexibilidade e elasticidade às fibras. Não é conhecido nenhum outro processo que possa causar este efeito, que se deve à particularidade do modo de funcionamento da tecnologia de alta pressão hidrostática, nomeadamente às elevadas forças físicas que a mesma exerce nos produtos processados. Sendo assim, o tratamento por alta pressão hidrostática alarga as áreas de utilização de pastas celulósicas que tenham sido submetidas a secagem (incluindo pastas recicladas) e altera as propriedades das pastas nunca secas . Após tratar pastas celulósicas por alta pressão, obtêm-se folhas de papel com maior índice de mão (volume por unidade de peso de papel) e melhores propriedades de resistência fisico-mecânica, comparativamente às folhas obtidas a partir de pastas não processadas. Isso permite obter papéis com propriedades mais robustas e diversificadas para a utilização do consumidor final (Figura 2), actualmente impossíveis de obter pelos métodos industriais correntes ou descritos na literatura científica. At the same time, high hydrostatic pressure processing causes the pastes to hydrate, forcing the incorporation of water molecules that are tightly bound to the amorphous and inaccessible regions of the cellulose structure and which are removed only at temperatures above 300 ° C. Thus, the hydration of the pulps promoted by the high hydrostatic pressure causes the fibers to recover some of their swelling capacity, leading to the reduction of the effects of hornification on dry pulps and giving greater flexibility and elasticity to the fibers. No other process can cause this effect, which is due to the particularity of the way hydrostatic high-pressure technology operates, namely the high physical forces it exerts on processed products. Thus, hydrostatic high pressure treatment extends the areas of use of dried pulps (including recycled pulps) and alters the properties of the never dried pulps. After treating cellulosic pulps by high pressure, sheets of paper with higher hand index (volume per unit weight of paper) and better physical-mechanical strength properties are obtained compared to sheets obtained from unprocessed pulps. This allows for papers with more robust and diverse properties for end-user use (Figure 2), which are currently impossible to obtain by current industrial methods or described in the scientific literature.
É de salientar ainda que após a hidratação a reactividade da pasta celulósica aumenta, devido ao aumento da sua acessibilidade para a interacção com reagentes químicos, possibilitando novas e melhoradas reacções químicas. It is also noteworthy that after hydration the reactivity of the pulp increases due to its increased accessibility to interaction with chemical reagents, enabling new and improved chemical reactions.
Estas alterações estruturais e de hidratação podem ser utilizadas para a modificação química de celulose para diversas aplicações. Como exemplo, a hidrólise com ácido sulfúrico diluído das pastas submetidas ao processamento por alta pressão hidrostática, permite hidrolisar mais rapidamente e em maior extensão as partes amorfas da celulose, comparando com a celulose de pastas não processadas por alta pressão hidrostática, quer em pastas previamente secas quer em pastas nunca secas. Assim, o processamento por alta pressão hidrostática permite obter novos produtos como celulose microcristalina, proporcionando não só produtos com diferente granulometria de partículas, mas também com maior grau de cristalinidade da celulose, com aplicações, por exemplo como matéria-prima para a indústria papeleira ou como excipiente nas indústrias química, alimentar e farmacêutica. These structural and hydration changes can be used for chemical modification of cellulose for various applications. As an example, dilute sulfuric acid hydrolysis of pastes subjected to high hydrostatic pressure processing enables the amorphous parts of the cellulose to be hydrolysed more rapidly and to a greater extent compared to the cellulose of hydrostatic high-pressure unprocessed pastes or pastes. dried or in pastes never dried. Thus, hydrostatic high pressure processing yields new products such as microcrystalline cellulose, providing not only products with different particle size but also with a higher degree of crystallinity of the cellulose, with applications, for example as a raw material for the paper industry or excipient in the chemical, food and pharmaceutical industries.
O método de modificação de pastas celulósicas objecto deste invento e abaixo descrito pode ser aplicado a pastas secas/nunca secas, sujeitas ou não a refinação. The cellulosic pulp modification method object of this invention and described below can be applied to dry / never dry pulps, whether or not refined.
1. Processamento por alta pressão hidrostática: Antes do tratamento por alta pressão hidrostática, as pastas celulósicas são intumescidas em água durante 0,5-24h, preferencialmente sob agitação moderada, de modo a obter suspensões com consistência entre 0,1- 40,0%. Após o intumescimento, as suspensões das pastas são processadas a frio ou quente por alta pressão hidrostática (entre 100-1000 MPa, mas podendo ser superior) a temperaturas entre 0 e 100°C durante até 75 minutos (podendo ser superior) . O processamento por alta pressão hidrostática pode ser realizado com as pastas em recipientes de tamanho e geometria variados ou em massa. 1. Hydrostatic high pressure processing: Prior to treatment by high hydrostatic pressure, the cellulosic pastes are swollen in water for 0.5-24h, preferably under moderate agitation, to obtain suspensions of 0.1-40.0% consistency. After swelling, slurry suspensions are processed cold or hot under high hydrostatic pressure (between 100-1000 MPa, but may be higher) at temperatures between 0 and 100 ° C for up to 75 minutes (and may be higher). Hydrostatic high pressure processing can be performed with pastes in containers of varying size and geometry or by mass.
O processamento por alta pressão é aplicável a qualquer tipo de pastas celulósicas com consistência entre 0,1 e 40,0%, preferivelmente em meio aquoso, mas não só. As etapas para que esta modificação ocorra envolvem : High pressure processing is applicable to any type of pulp having a consistency between 0.1 and 40.0%, preferably in aqueous medium, but not only. The steps for this modification to take place involve:
Ia etapa: intumescimento das pastas celulósicas em água durante 0,5-24h, preferencialmente sob agitação moderada, de modo a obter suspensões com consistências variadas; e Step I: swelling of the cellulose pulp in water for 0,5-24h, preferably under mild agitation, to obtain suspensions of varying consistencies; and
2a etapa: após o intumescimento, as suspensões das pastas são processadas a frio ou quente por alta pressão hidrostática (entre 100-1000 MPa, mas podendo ser superior) a temperaturas entre 0 e 100°C durante até 75 minutos (podendo ser superior) . Step 2: After swelling, the suspension folders are processed by cold or hot high hydrostatic pressure (between 100-1000 MPa, but may be higher) at temperatures between 0 and 100 ° C for up to 75 minutes (can be more than ).
O tratamento por alta pressão hidrostática das pastas promove o aumento do tamanho dos cristalitos de celulose, através da cocristalização e recristalização parcial dos domínios paracristalinos na superfície das fibrilas elementares, provocando o aumento da largura média de cristalito da celulose (parâmetro d002), assim como o aumento do seu grau de cristalinidade . Simultaneamente, a hidratação forçada causada pelos tratamentos por alta pressão hidrostática, promove a incorporação de moléculas de água que ficam fortemente ligadas às regiões amorfas da celulose, aumentando a sua acessibilidade para a interacção com reagentes químicos. Desta forma, relativamente à pasta actualmente presente no mercado, as alterações estruturais sofridas pela pasta tratada por alta pressão fazem com que apresente cristalitos mais largos, com maior grau de cristalinidade, e as suas fibras apresentam maior capacidade de absorção de água, assim como flexibilidade e elasticidade acrescidas. Devido ao aumento das propriedades mecânicas, é necessária uma menor quantidade de pasta celulósica para atingir a mesma resistência no papel, o que implica uma poupança de matéria-prima . Todas estas alterações fazem com que a pasta tratada se torne uma excelente matéria-prima não só para a produção de papel com propriedades melhoradas, mas também para outras aplicações, como novos materiais e para reacções de modificação química da celulose, com variadas possíveis aplicações. The treatment by high hydrostatic pressure of the pulps promotes the increase in the size of the cellulose crystallites through the cocrystallization and partial recrystallization of the paracrystalline domains on the surface of the elemental fibrils, causing the increase of the average cellulose crystallite width (parameter d002). increasing its degree of crystallinity. At the same time, forced hydration caused by High hydrostatic pressure treatments promote the incorporation of water molecules that are tightly bound to the amorphous regions of cellulose, increasing their accessibility for interaction with chemical reagents. Thus, in relation to the pulp currently on the market, the structural changes suffered by the high pressure treated pulp make it present larger crystallites, with higher degree of crystallinity, and its fibers have a higher water absorption capacity, as well as flexibility. and increased elasticity. Due to the increase in mechanical properties, less pulp is required to achieve the same strength in paper, which saves raw material. All these changes make the treated pulp become an excellent raw material not only for producing paper with improved properties, but also for other applications such as new materials and for chemical modification reactions of cellulose, with various possible applications.
Hidrólise ácida Acid hydrolysis
As vantagens anteriormente apresentadas associadas às alterações estruturais e de hidratação das pastas celulósicas permitem melhorar a rapidez e extensão das reacções de modificação química da celulose, para diversas aplicações. Por exemplo, se após processamento a alta pressão hidrostática das pastas (pelo método acima referido) se proceder à sua hidrólise com ácido sulfúrico diluído, é possível hidrolisar mais rapidamente e em maior extensão as partes amorfas da celulose, comparando com a celulose de pastas não processadas por alta pressão hidrostática, quer em pastas previamente secas quer em pastas nunca secas. The advantages presented above associated with the structural and hydration changes of cellulose pulps allow to improve the speed and extent of chemical modification reactions of cellulose for various applications. For example, if the high hydrostatic pressure of the pulps (by the above method) is hydrolysed with dilute sulfuric acid, the amorphous parts of the cellulose can be hydrolysed more rapidly and to a greater extent as compared to non-pulp pulp. processed by high pressure hydrostatic, either in previously dried or in never dried pastes.
Após processamento por alta pressão hidrostática e secagem, a pasta é intumescida em água (em concentrações variáveis, tipicamente 5% m/m) . A hidrólise ácida ocorre sob refluxo, na presença de ácido sulfúrico diluído com concentração entre 1,0 e 2,0M, preferencialmente 1,8 M, durante um intervalo de tempo compreendido entre 0,5-5h. Após a reacção e arrefecimento, a mistura é filtrada e lavada com água destilada até obter uma pasta com pH próximo de 7. De seguida a pasta é seca na estufa a 105°C até peso constante . After high hydrostatic pressure processing and drying, the pulp is swollen in water (at varying concentrations, typically 5% w / w). Acid hydrolysis occurs under reflux in the presence of dilute sulfuric acid with a concentration between 1.0 and 2.0 M, preferably 1.8 M, over a period of 0.5-5h. After the reaction and cooling, the mixture is filtered and washed with distilled water to a paste with a pH close to 7. Then the paste is oven dried at 105 ° C to constant weight.
A presente invenção propõe um processo que consiste na modificação das propriedades de pastas celulósicas através do processamento por alta pressão hidrostática, aplicável a qualquer tipo de pastas preferivelmente em meio aquoso, mas não só, com consistência entre 0,1 e 40,0%. As pastas assim tratadas sofrem alterações estruturais ao nível da celulose (aumento da largura média de cristalito) , aumento da acessibilidade da celulose amorfa e incorporação de moléculas de água ligadas à celulose, o que melhora a hidratação das pastas. O processamento de pastas previamente secas restaura a sua capacidade de intumescimento, diminuindo os problemas de hornificação . As alterações estruturais da celulose aumentam a força intrínseca da fibra, e a hidratação confere-lhe flexibilidade, elasticidade e capacidade de ligação, melhorando as suas propriedades físicas, sem diminuir o índice de mão. O invento permite produzir pastas com propriedades diferentes, para diversas aplicações, como na produção de papel com diferentes e melhoradas características, em reacções de modificação química melhoradas da celulose, bem como para outras aplicações. Os resultados sem precedentes alcançados com o processamento por alta pressão das pastas celulósicas, fazem com que esta invenção possa ser aplicada: The present invention proposes a process of modifying the properties of cellulose pulps by hydrostatic high pressure processing, applicable to any type of pulp, preferably in aqueous medium, but not only, with a consistency between 0.1 and 40.0%. The pulp thus treated undergoes structural changes in cellulose (increased average crystallite width), increased accessibility of amorphous cellulose and incorporation of cellulose-bound water molecules, which improves the hydration of the pulp. The processing of previously dried pastes restores their swelling capacity, reducing hornification problems. Structural changes in cellulose increase the intrinsic strength of the fiber, and hydration gives it flexibility, elasticity and binding capacity, improving its physical properties without decreasing the hand index. The invention makes it possible to produce pulps with different properties for various applications, such as in the production of paper with different and improved characteristics, in improved cellulose chemical modification reactions as well as for other applications. The unprecedented results achieved with the high pressure processing of cellulosic pulps make it possible for this invention to be applied:
i. À indústria papeleira - a ocorrência de hornificação após secagem das pastas é um dos motivos para que seja necessário recorrer à sua refinação. No entanto, esta etapa representa gastos energéticos significativos numa unidade fabril, que serão significativamente diminuídos com o tratamento por alta pressão hidrostática das pastas. Esta aplicação deve-se ao facto dos tratamentos por alta pressão hidrostática reduzirem significativamente os problemas de hornificação, devido à incorporação de moléculas de água que ficam fortemente ligadas à estrutura da celulose e aí permanecem mesmo após a secagem das pastas. Esta hidratação confere também muita flexibilidade às fibras, fazendo com que as suas propriedades de resistência mecânica sejam bastante superiores às das pastas não tratadas. A hidratação das pastas reflecte-se também em termos de poupança de matéria-prima : torna-se possível obter papéis com melhores propriedades físicas e ópticas utilizando menor quantidade de fibras. ii. À indústria química especializada em produtos à base de celulose - o aumento do tamanho de cristalito e o aumento do grau de cristalinidade após tratamento por alta pressão hidrostática, aliados ao aumento da acessibilidade da celulose amorfa face ao ataque de reagentes químicos, são factos que fazem com que a celulose processada por alta pressão hidrostática, reúna um conjunto de características únicas, que a tornam um melhor reagente para sofrer reacções de modificação química na indústria de transformação de celulose em geral. i. To the paper industry - the occurrence of hornification after drying of the pulp is one of the reasons why it is necessary to refine it. However, this step represents significant energy costs in a plant, which will be significantly reduced with the high hydrostatic pressure treatment of the pastes. This application is due to the fact that high hydrostatic pressure treatments significantly reduce the problems of hornification due to the incorporation of water molecules that are tightly bound to the cellulose structure and remain there even after the pastes have dried. This hydration also gives the fibers a great deal of flexibility, making their mechanical strength properties far superior to untreated pulps. The hydration of the pastes is also reflected in terms of raw material savings: it is possible to obtain papers with better physical and optical properties using fewer fibers. ii. To the chemical industry specializing in cellulose-based products - Increasing crystallite size and increasing crystallinity after high hydrostatic pressure treatment, coupled with increased accessibility of amorphous cellulose to attack by chemical reagents, are facts that make The high hydrostatic pressure processed cellulose has a unique set of characteristics that make it a better reagent to undergo chemical modification reactions in the cellulose processing industry in general.
Sumário da Invenção A presente invenção refere-se a um processo de modificação de pastas celulósicas que compreende os seguintes passos: Summary of the Invention The present invention relates to a cellulosic pulp modification process comprising the following steps:
a) desintegração e intumescimento da pasta com água durante 0,5 h a 24 h, sob agitação;  a) disintegration and swelling of the pulp with water for 0.5 h to 24 h under agitation;
b) processamento da pasta por alta pressão hidrostática de preferência entre 100-1000 MPa que leva à incorporação de moléculas de água fortemente ligada em locais inacessíveis de polissacarídeos .  b) pulp processing by hydrostatic high pressure preferably between 100-1000 MPa which leads to the incorporation of strongly bound water molecules in inaccessible polysaccharide sites.
Numa realização preferencial o passo b) ocorre a temperaturas entre 0-100 °C durante um intervalo de tempo variável entre 1-75 minutos. In a preferred embodiment step b) occurs at temperatures between 0-100 ° C for a time period ranging from 1-75 minutes.
Numa outra realização preferencial o processo é aplicável a qualquer pasta celulósica com consistência na gama de 0,1-40,0%, sendo ainda aplicável a pastas secas ou nunca secas, sujeitas ou não a refinação. In another preferred embodiment the process is applicable to any cellulose pulp having a consistency in the range 0.1-40.0%, and is further applicable to dried or never dried pulps, whether or not refined.
A presente invenção refere-se ainda as pastas celulósicas modificadas que são obtidas pelo processo descrito anteriormente. The present invention further relates to modified cellulosic pastes which are obtained by the process described above.
As pastas celulósicas da presente invenção são utilizadas como pastas papeleiras ou para o fabrico de produtos para as indústrias química, alimentar, farmacêutica e de biotecnologia. The cellulosic pulps of the present invention are used as paper pulps or for the manufacture of products for the chemical, food, pharmaceutical and biotechnology industries.
Exemplos Examples
Para uma mais fácil compreensão da invenção descrevem-se de seguida exemplos de realizações preferenciais do invento, as quais, contudo, não pretendem limitar o objecto da presente invenção.  For an easier understanding of the invention, the following are examples of preferred embodiments of the invention which, however, are not intended to limit the scope of the present invention.
Resultados obtidos para dois tipos de pastas (sulfito ácido e kraft, de entre os vários estudados) : Para este exemplo o processamento foi efectuado a uma pressão de 400 MPa, durante 10 min a 20°C, com uma pasta com consistência de 5% (m/m) . Results obtained for two types of pastes (acid sulfite and kraft, among the several studied): For this example processing was performed at a pressure of 400 MPa for 10 min at 20 ° C with a 5% (w / w) paste.
Para comparação, apresentam-se também os resultados referentes a pastas não processadas.  For comparison, the results for unprocessed folders are also presented.
Na Tabela 1 apresentam-se os parâmetros da rede cristalina da celulose de ambas as pastas, antes e após tratamento por alta pressão hidrostática. Os parâmetros a e b correspondem à dimensão da célula unitária dos eixos a e b representados na Figura 1, respectivamente; c representa a altura média de cristalito, ^representa o ângulo monoclinico formado e doo2 a largura média de cristalito no plano de rede 002. A largura média do cristalito aumenta com o processamento por alta pressão hidrostática, sendo este efeito mais significativo para a pasta kraft. Table 1 shows the parameters of the cellulose crystal lattice of both pastes, before and after treatment by high hydrostatic pressure. Parameters a and b correspond to the unit cell size of axes a and b shown in Figure 1, respectively; c represents the average crystallite height, ^ represents the monoclinic angle formed and doo2 the average crystallite width in the 002 plane. The average crystallite width increases with high hydrostatic pressure processing, this effect being more significant for kraft pulp. .
Tabela 1: Comparação dos parâmetros da rede cristalina celulose nas pastas kraft e sulfito, processadas e processadas por alta pressão hidrostática. Table 1: Comparison of the parameters of the cellulose crystal lattice in kraft and sulfite pulps, processed and processed by high hydrostatic pressure.
Figure imgf000012_0001
Figure imgf000012_0001
As principais diferenças observadas nos parâmetros de cristalito de celulose ocorrem ao nível da largura média de cristalito, doo2- As alterações obtidas, para as mesmas condições de operação, dependem do tipo de pasta em questão (pasta submetida a cozimento sulfito ou kraft) . Para toda a gama de parâmetros testada o aumento da largura média de cristalito verificado para pastas sulfito variou entre 1- 10%, enquanto para pastas kraft o aumento variou entre 1- 20%. The main differences observed in the parameters of cellulose crystallite occur at the level of the average crystallite width, doo2- The changes obtained, for the same operating conditions, depend on the type of paste in question (paste subjected to sulfite or kraft cooking). For the whole range of parameters tested the increase of the average width of The verified crystallite for sulfite pastes ranged from 1-10%, while for kraft pastes the increase ranged from 1-20%.
Na Tabela 2 apresentam-se as alterações ocorridas ao nível da fracção cristalina da celulose presente nas pastas sulfito ácido e kraft, antes e após tratamento por alta pressão hidrostática, sendo evidente o aumento do grau de cristalinidade, índice de cristalinidade, e parâmetro de cristalinidade da celulose das pastas, causado pelo processamento por alta pressão hidrostática. Table 2 shows the changes in the crystalline fraction of the cellulose present in the acid and kraft sulfite pastes, before and after treatment by high hydrostatic pressure, showing the increase in the degree of crystallinity, crystallinity index, and crystallinity parameter. pulp, caused by high hydrostatic pressure processing.
Tabela 2: Grau de cristalinidade, GC, índice de cristalinidade, IC, e parâmetro de cristalinidade, PC, da celulose presente nas pastas antes e após processamento por alta pressão hidrostática, obtidos por Raio-X, 13C RMN e FTIR, respectivamente. Table 2: Degree of crystallinity, GC, crystallinity index, IC, and crystallinity parameter, PC, of pulp present in pastes before and after hydrostatic high pressure processing, obtained by X-ray, 13 C NMR and FTIR, respectively.
Figure imgf000013_0001
Figure imgf000013_0001
O aumento do grau de cristalinidade pode variar entre 1,0 e 7,0% (determinado por difracção de Raios-X) . The increase in the degree of crystallinity may range from 1.0 to 7.0% (determined by X-ray diffraction).
Na Tabela 3 encontra-se evidenciado o efeito que a etapa de secagem exerce sobre o grau de hornificação de uma pasta, sendo que o processamento por alta pressão hidrostática permite reduzir a hornificação da pasta seca a 140°C (temperatura à qual ocorre a secagem de pastas na indústria papeleira) , para valores próximos dos exibidos pela pasta seca ao ar. No entanto, este valor está sobreestimado porque a hornificação é calculada através da comparação da capacidade de absorção de água de uma pasta nunca seca e seca e, neste caso, não é possível contabilizar a água que após processamento a alta pressão hidrostática fica fortemente ligada à estrutura da celulose e que só se consegue libertar da celulose a temperaturas muito elevadas, como se referiu acima. Desta forma, a redução da ocorrência do efeito de hornificação da celulose da pasta processada por alta pressão hidrostática será ainda maior que o valor apresentado. Table 3 shows the effect of the drying step on the degree of hornification of a paste, and processing by high hydrostatic pressure reduces the hornification of dry paste to 140 ° C (temperature at which drying occurs in the paper industry), to values close to those shown by air-dried pulp. However, this value is overestimated because hornification is calculated by comparing the water absorption capacity of a never dry and dry pulp and in this case it is not possible to account for water which after processing at high hydrostatic pressure is strongly bound to the cellulose structure and which can only be released from cellulose at very high temperatures, as mentioned above. Thus, the reduction of the occurrence of the hornification effect of the pulp of the pulp processed by high hydrostatic pressure will be even greater than the value presented.
Tabela 3 : Efeitos das diferentes condições de secagem e do tratamento a alta pressão hidrostática na hornificação sofrida por uma pasta sulfito. Table 3: Effects of different drying conditions and high hydrostatic pressure treatment on the hornification of a sulphite paste.
Figure imgf000014_0001
Figure imgf000014_0001
Na Figura 2 está representado o comportamento mecânico de folhas de papel produzidas a partir de uma pasta sulfito ácido seca, com e sem tratamento por alta pressão hidrostática, sendo evidente que o processamento por alta pressão aumenta as propriedades de resistência mecânica (resistência à tracção, ao rasgamento, ao rebentamento e à tracção zero span) , como resultado da incorporação de moléculas de água fortemente ligadas à estrutura da celulose, que para além de conferirem maior flexibilidade às fibras, provocam a diminuição dos efeitos provocados pela hornificação. Após tratamento a alta pressão hidrostática é possível obter folhas de papel com propriedades de resistência mecânica acrescidas. Observaram-se aumentos na resistência à tracção entre 20-40%, na resistência ao rebentamento entre 40-60% e na resistência à tracção zero span entre 10- 20%. Relativamente à resistência ao rasgamento, o aumento verificado variou de 80 a 300%. Figure 2 shows the mechanical behavior of paper sheets made from a dry acid sulphite pulp, with and without high hydrostatic pressure treatment. It is evident that high pressure processing increases the mechanical strength properties (tensile strength, tearing, bursting and zero span traction), as a result of the incorporation of water molecules tightly bound to the cellulose structure, which in addition to giving greater flexibility to the fibers, cause the effects of hornification to diminish. After treatment at high hydrostatic pressure it is possible to obtain sheets of paper with increased mechanical strength properties. Increases in tensile strength of 20-40%, burst strength of 40-60% and zero-tensile strength of 10-20% were observed. Regarding the tear strength, the increase increased from 80 to 300%.
O processamento por alta pressão hidrostática permite realizar hidrolise química da celulose mais rapidamente e também de modo mais extenso, resultando em maior quantidade de celulose hidrolisada. Hydrostatic high pressure processing allows for chemical hydrolysis of cellulose faster and also more extensively, resulting in higher amounts of hydrolyzed cellulose.
Na Tabela 4 é apresentado um exemplo dos resultados obtidos para o grau de cristalinidade e largura média de cristalito, d002 , da celulose após a hidrólise. Estes dois parâmetros aumentam com o pré-processamento por alta pressão hidrostática. Table 4 gives an example of the results obtained for the degree of crystallinity and mean crystallite width, d 0 02, of the cellulose after hydrolysis. These two parameters increase with high hydrostatic pressure preprocessing.
Tabela 4: Comparação da largura média de cristalito, d002, e grau de cristalinidade, GC, da celulose presente numa pasta após hidrólise. Table 4: Comparison of mean crystallite width, d002, and degree of crystallinity, GC, of cellulose present in a pulp after hydrolysis.
Figure imgf000015_0001
Figure imgf000015_0001
Descrição das Figuras  Description of the Figures
Para uma mais fácil compreensão da invenção juntam-se em anexo as figuras, as quais, representam realizações preferenciais do invento que, contudo, não pretendem, limitar o objecto da presente invenção. Na Figura 1 está representado o difractograma de raio-X da pasta sulfito ácido, com a representação dos respectivos halos amorfos e cristalinos. Projecção da célula unitária da celulose com as respectivas dimensões e planos de rede. For easier understanding of the invention, attached are the figures which represent preferred embodiments of the invention which, however, are not intended to limit the scope of the present invention. Figure 1 shows the X-ray diffractogram of the acid sulphite paste, with the representation of the respective amorphous and crystalline halos. Projection of the cellulose unit cell with its dimensions and network plans.
Na Figura 2 está representado o comportamento mecânico de folhas de papel produzidas a partir de uma pasta sulfito ácido seca a 140°C, com e sem tratamento por alta pressão hidrostática . Figure 2 shows the mechanical behavior of paper sheets produced from a dry acid sulfite paste at 140 ° C, with and without treatment by high hydrostatic pressure.
Referências References
Patentes : Patents:
US 4,385,172; 05/1983; Yasnovsky et al . ; Prevention of hornification of dissolving pulp.  US 4,385,172; 05/1983; Yasnovsky et al. ; Prevention of hornification of dissolving pulp.
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US 5,932,272; 10/1968; Pierre Carvallo; Hydrostatic pressure type continuous sterilizing and cooling apparatus. US 5,213,029; 05/1993; Hideki Yutaka; Apparatus for treating food under high pressure.  US 5,932,272; 10/1968; Pierre Carvallo; Hydrostatic pressure type continuous sterilizing and cooling apparatus. US 5,213,029; 05/1993; Hideki Yutaka; Apparatus for treating food under high pressure.
US 5,658,610; 08/1997; Carl Bergman et al . ; Method and device in high-pressure treatment of liquid substances. US 6,110,516; 08/2000; Dallas G. Hoover et al . ; Process for treating foods using saccharide esters and superatmospheric hydrostatic pressure. US 6,217,435 BI; 04/2001; Ernest A. Voisin; Process of elimination of bactéria in shellfish, of shucking shellfish and an apparatus therefor. US 5,658,610; 08/1997; Carl Bergman et al. ; Method and device in high-pressure treatment of liquid substances. US 6,110,516; 08/2000; Dallas G. Hoover et al. ; Process for treating foods using saccharide esters and superatmospheric hydrostatic pressure. US 6,217,435 BI; 04/2001; Ernest A. Voisin; Process of elimination of bacteria in shellfish, shucking shellfish and an apparatus therefor.
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Artigos : Articles:
Chen D, Guo Y, Huang RB, et al . ; Pretreatment by ultra-high pressure explosion with homogenizer facilitates cellulose digestion of sugarcane bagasses; Bioresource Technology (2010) , 101 (14) : 5592-5600.  Chen D, Guo Y, Huang RB, et al. ; Pretreatment by ultra-high pressure explosion with homogenizer facilitates cellulose digestion of sugarcane bagasses; Bioresource Technology (2010), 101 (14): 5592-5600.
Kumar S, Gupta R, Lee YY, et al; Cellulose pretreatment in subcritical water: effect of temperature on molecular structure and enzymatic reactivity; Bioresource Technology (2010) , 101 (4) : 1337-1347. Kumar S, Gupta R, Lee YY, et al; Cellulose pretreatment in subcritical water: effect of temperature on molecular structure and enzymatic reactivity; Bioresource Technology (2010), 101 (4): 1337-1347.
As reivindicações seguintes representam adicionalmente realizações preferenciais da presente invenção. The following claims further represent preferred embodiments of the present invention.

Claims

R E I V I N D I C A Ç Õ E S
1. Processo de modificação de pastas celulósicas caracterizado por compreender os seguintes passos : Process for the modification of cellulose pulp comprising the following steps:
c) desintegração e intumescimento da pasta com água durante 0,5 h a 24 h, sob agitação;  c) disintegration and swelling of the pulp with water for 0.5 h to 24 h under agitation;
d) processamento da pasta por alta pressão hidrostática de preferência entre 100-1000 MPa que leva à incorporação de moléculas de água fortemente ligada em locais inacessíveis de polissacarídeos .  d) hydrostatic high pressure pulp processing preferably between 100-1000 MPa which leads to the incorporation of strongly bound water molecules into inaccessible polysaccharide sites.
2. Processo de modificação de pastas celulósicas de acordo com a reivindicação anterior caracterizado por ser aplicável a qualquer pasta celulósica com consistência na gama de 0,1- 40, 0%. Process for modifying cellulose pulp according to the preceding claim, which is applicable to any cellulose pulp having a consistency in the range 0.1-40.0%.
3. Processo de modificação de pastas celulósicas de acordo com as reivindicações 1-2 caracterizado por o passo b) ocorrer a temperaturas entre 0- 100 °C durante um intervalo de tempo variável entre 1-75 minutos. Process for modifying cellulose pulps according to claims 1-2, characterized in that step b) takes place at temperatures between 0-100 ° C for a variable time period between 1-75 minutes.
4. Processo de modificação de pastas celulósicas de acordo com as reivindicações 1-3 caracterizado por ser aplicado a pastas secas ou nunca secas, sujeitas ou não a refinação. Process for modifying cellulose pulps according to claims 1-3, characterized in that it is applied to dried or never dried pulps, whether or not refined.
5. Pastas celulósicas modificadas caracterizadas por serem obtidas pelo processo descrito nas reivindicações 1-4. Modified cellulosic pastes characterized in that they are obtained by the process described in claims 1-4.
6. Utilização das pastas celulósicas descritas na reivindicação anterior e obtidas pelo processo descrito nas reivindicações 1-4 caracterizadas por serem utilizadas como pastas papeleiras ou para o fabrico de produtos nas indústrias química, alimentar, farmacêutica e de biotecnologia. Use of the cellulosic pulps described in the preceding claim and obtained by the process described in claims 1-4 characterized in as they are used as paper pulp or for the manufacture of products in the chemical, food, pharmaceutical and biotechnology industries.
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Citations (17)

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