阅读说明：本技术 一种高聚合度木浆及其制备方法 (A kind of high polymerization degree wood pulp and preparation method thereof ) 是由 方志强 曹成志 刘宇 李冠辉 侯高远 李南星 朱兰萍 张德健 于 2019-08-22 设计创作，主要内容包括：本发明提供的一种高聚合度木浆及其制备方法。该方法包括：将木材切片,得到木片,将木片加入双螺旋挤压机中,进行机械预处理,得到机械预处理后的木片；将机械预处理后的木片加入蒸煮液中,浸泡,加入保护剂和渗透助剂,混匀,得到混合液,将混合液升温进行蒸煮处理,得到蒸煮处理后的混合物,过滤,得到蒸煮后的浆料；清洗,疏解,筛分,然后加入漂白液中进行漂白处理,清洗得到高聚合度木浆。该方法中的蒸煮后的浆料的木素含量小于4%,制得的高聚合度木浆的聚合度最高可达到2517,是普通商业浆(900～1200)的两倍多。本发明提供的制备方法,有利于促进木浆纤维在汽车、能源、柔性电子等高附加值领域的应用。(A kind of high polymerization degree wood pulp provided by the invention and preparation method thereof.This method comprises: Wooden slice is obtained wood chip, wood chip is added in double-screw extrusion machine, carries out mechanical pretreatment, the wood chip after obtaining mechanical pretreatment；Wood chip after mechanical pretreatment is added in cooking liquor, is impregnated, protective agent and penetrant is added, mixes, obtains mixed liquor, mixed liquor is heated up and carries out boiling processing, obtains boiling treated mixture, filtering, the slurry after obtaining boiling；Cleaning, is discongested, and is sieved, and is then added in bleaching liquid and is carried out bleaching, and cleaning obtains high polymerization degree wood pulp.For the lignin content of the slurry after boiling in this method less than 4%, the degree of polymerization of high polymerization degree wood pulp obtained can reach 2517, be common commercial more than twice of (900~1200) of slurry.Preparation method provided by the invention may advantageously facilitate wood pulp cellulose in the application of the value segments such as automobile, the energy, flexible electronic.)

1. a kind of preparation method of high polymerization degree wood pulp, which comprises the steps of:

(1) by Wooden slice, wood chip is obtained, then the wood chip is added in double-screw extrusion machine, mechanical pretreatment is carried out, obtains Wood chip after to mechanical pretreatment；

(2) wood chip after step (1) described mechanical pretreatment is added in cooking liquor, carries out immersion treatment, protection is then added Agent and penetrant are uniformly mixed, obtain mixed liquor, and the mixed liquor is transferred to heating in reaction kettle and carries out boiling processing, Boiling is obtained treated mixture, filters to take precipitating, the slurry after obtaining boiling；

(3) slurry after cleaning step (2) described boiling, is discongested, then screening is added in bleaching liquid and carries out bleaching, clearly It washes to obtain the high polymerization degree wood pulp.

2. the preparation method of high polymerization degree wood pulp according to claim 1, which is characterized in that step (1) described timber is Needlebush timber；The needlebush timber is one or more of masson pine, Korean pine, dragon spruce, Chinese hemlock spruce and fir；The wood chip With a thickness of 2-4 millimeters.

3. the preparation method of high polymerization degree wood pulp according to claim 1, which is characterized in that step (1) is described mechanical pre- Number of processing is 2-3 times, and the pressure of mechanical pretreatment is 0.8-1.2MPa, and the temperature of the mechanical pretreatment is 20-30 DEG C, The time of each mechanical pretreatment is 5-10min.

4. the preparation method of high polymerization degree wood pulp according to claim 1, which is characterized in that step (2) described cooking liquor Preparation, comprising: sodium hydroxide and sodium sulfite are added in methanol solution, is uniformly mixed, obtains the cooking liquor；The first The concentration expressed in percentage by volume of alcoholic solution is 10-30%；In the cooking liquor, the mass percent concentration of sodium hydroxide is 2.5wt%； In the cooking liquor, the mass percent concentration of sodium sulfite is 4.23wt%.

5. the preparation method of high polymerization degree wood pulp according to claim 1, which is characterized in that step (2) is described mechanical pre- The mass ratio of treated wood chip and cooking liquor is 1:10-1:50, and the time of the immersion treatment is 1-2 days；The protective agent For one of anthrahydroquinone, dihydro-anthraquinone, tetrahydro-anthraquinone, 2-methylanthraquinone and sodium polysulfide, protectant quality is institute The 0.06-0.10% of chip quality after stating mechanical pretreatment.

6. the preparation method of high polymerization degree wood pulp according to claim 1, which is characterized in that step (2) described protective agent It is anionic surfactant for penetrant, the penetrant is neopelex, xylene monosulfonic acid and condensation One of sodium naphthalene sulfonate；The quality of the penetrant is 40% of the chip quality after the mechanical pretreatment.

7. the preparation method of high polymerization degree wood pulp according to claim 1, which is characterized in that step (2) described boilery The temperature of reason is 150-170 DEG C, and the time of the boiling processing is 3-5 hours.

8. the preparation method of high polymerization degree wood pulp according to claim 1, which is characterized in that step (3) described bleaching liquid Preparation, comprising: sodium chlorite and glacial acetic acid are added to the water, be uniformly mixed obtain the bleaching liquid；In the bleaching liquid, The mass percent concentration of the sodium chlorite is 0.60%-0.80%；In the bleaching liquid, the quality percentage of the glacial acetic acid Specific concentration is 0.80-0.10%；The temperature of the bleaching is 70-80 DEG C, and the time of bleaching is 1-2h.

9. the preparation method of high polymerization degree wood pulp according to claim 1, which is characterized in that after step (3) described boiling Slurry and bleaching liquid mass volume ratio be 0.37:1g/mL.

10. a kind of high polymerization degree wood pulp as made from claim 1-9 described in any item preparation methods.

Technical field

The invention belongs to paper pulp papermaking fields, and in particular to a kind of high polymerization degree wood pulp and preparation method thereof.

Background technique

In recent years, becoming increasingly conspicuous with problem of environmental pollution, pay attention to day by day of the people to environmental protection, bio-based materials Because its unique characteristic causes the extensive concern and interest of people.Cellulose is maximum as reserves in nature, distribution is most wide Natural polymers, have the characteristics that it is pollution-free, recyclable, degradable so that cellulosic-based material is widely used in people Each corner of class society, the effective development and progress for pushing human society.With the progress of nanotechnology, the mankind can be from Nano-cellulose is isolated in wood pulp cellulose, other than it is in addition to the cellulose the advantages of, also shows excellent optical property and mechanics Performance.There is bright application in emerging fields such as the energy, electronic device and biomedicines based on the material of nano-cellulose Prospect is expected to alleviate because of white pollution bring carrying capacity of environment, and power-assisted is in the sustainable development of human society.

It is all to be prepared using commercial wood pulp as raw material by specific technique that existing nano-cellulose is most of.This A little commercial pulps generally use sulphite process or sulfate pulping, the infiltration and sulfonation using cooking liquor to raw material, with raw material In lignin chemical reaction occur generate lignosulphonic acid or lignosulphonates, cellulose contained in fiber and hemicellulose also exist By different degrees of degradation in cooking liquor, and partial hydrolysis dissolves out.Finally reaction product is dissolved out and is separated with raw material At fibrous paper pulp.These pulping process are cheap, high production efficiency and are produced on a large scale, and the wood pulp of preparation can fill Divide the Fundamental Physical Properties requirement for meeting paper.But continuing to bring out with emerging fields such as aerospace, flexible electronics, More stringent requirements are proposed to material mechanical performance by the mankind.The nano cellulose material of original pulping process preparation will be difficult to meet The demand of these emerging fields.Mainly these pulping process of tracing it to its cause can make wood pulp cellulose that strong degradation occur, and gather Right decline causes the performance of the nano-cellulose of preparation that serious damage occurs, causes to be difficult to meet high-strength nano-cellulose base The demand of material.

In response to this problem, Xue Qin etc. is by way of adding biological enzyme composite assistant, in conjunction with conventional boil liquid to cotton linter Boiling is carried out, the available degree of polymerization is at least 2500 boiling half stuff, but cotton price is high, will receive it should centainly Limitation；Liu Jianhuas etc. stablize the PH of cooking liquor by addition sodium metasilicate and magnesium sulfate, improve the stability of hydrogen peroxide, make double Oxygen water energy is enough slowly to decompose and has an effect, and adsorbs the metal ions such as the calcium in digestion system, iron, magnesium, avoids impurities accumulation On fiber, to improve cooking effect, the higher wood pulp cellulose of the degree of polymerization is obtained.But this method preparation efficiency is lower, Drug price is expensive, causes high production cost.

Summary of the invention

In order to overcome deficiencies of the prior art, the object of the present invention is to provide a kind of high polymerization degree wood pulp and its Preparation method.

Traditional industry slurrying is larger to the damage of wood fibre, the degree of polymerization is lower, is difficult to apply in order to solve by the present invention The problem of high-performance fiber element based composites field, improves slurrying process and technique, and fiber can preferably be retained by obtaining one kind The method of plain primary characteristic.While guaranteeing high cellulosic degree of polymerization, the high removal rate to lignin, hemicellulose is realized. In addition, the milder method for bleaching of use further retains the original shape of cellulose on the whiteness basis for meeting slurry State provides a kind of preparation method for improving the commercial pastes degree of polymerization.

The purpose of the present invention is realized at least through one of following technical solution.

The present invention provides a kind of preparation methods of high polymerization degree wood pulp.The preparation method is the following steps are included: by timber It is cut into smaller and thin rectangle wood chip；Mechanical treatment is carried out to wood chip using twin (double) screw extruder；By chip impregnation in cooking liquor Middle a period of time；Wood chip, cooking liquor, protective agent and penetrant are added in high-temperature high-pressure reaction kettle, boiling is carried out；It will steam The wood pulp boiled is cleaned, discongested and is sieved, and removes cooking liquor and residue therein, and by having selective delignification Bleaching process obtain high polymerization degree wood pulp.Less than 4%, bleached pulp gathers the lignin content of slurry after boiling in the present invention Right highest can achieve 2517, be common commercial more than twice of (900~1200) of slurry.The present invention is the wood for preparing high polymerization degree Pulp fibres provide a kind of method, may advantageously facilitate wood pulp cellulose answering in value segments such as automobile, the energy, flexible electronics With.

The present invention proposes a kind of preparation method of high polymerization degree wood pulp using timber as raw material.Pass through mechanical pretreatment and steaming Boil liquid is impregnated, and 2- hydroxy-anthraquione is added as protective agent before boiling, and anionic surfactant is as penetrant, to increase The infiltration of strong cooking liquor carries out boiling to timber using improved ASAM method, while realizing quick delignification, hinders as far as possible The only degradation of cellulose obtains the wood pulp cellulose of high polymerization degree.

The preparation method of high polymerization degree wood pulp provided by the invention be a kind of reservation wood fibre primary characteristic, improve it is wooden The method of fibrous polymer degree.

A kind of preparation method of high polymerization degree wood pulp provided by the invention, includes the following steps:

(1) by Wooden slice, wood chip (preferably rectangle wood chip) is obtained, then the wood chip is added in double-screw extrusion machine, Carry out mechanical pretreatment, the wood chip after obtaining mechanical pretreatment；

(2) wood chip after step (1) described mechanical pretreatment is added in cooking liquor, carries out immersion treatment, protection is then added Agent and penetrant are uniformly mixed, obtain mixed liquor, the mixed liquor is transferred to reaction kettle (preferably high-temperature high-pressure reaction kettle) Middle heating carries out boiling processing, obtains boiling treated mixture, filter to take precipitating, the slurry after obtaining boiling；

(3) slurry after cleaning step (2) described boiling, is discongested, then screening is added in bleaching liquid and carries out bleaching, clearly It washes to obtain the high polymerization degree wood pulp.

Further, step (1) timber is needlebush timber；The needlebush timber is masson pine, Korean pine, cloud One or more of China fir, Chinese hemlock spruce and fir；The wood chip with a thickness of 2-4 millimeters.

Preferably, step (1) wood chip is rectangle wood chip.

Preferably, step (1) wood chip is smaller and thin rectangle wood chip.

Further, the number of step (1) described mechanical pretreatment is 2-3 times, and the pressure of mechanical pretreatment is 0.8- 1.2MPa, the temperature of the mechanical pretreatment are 20-30 DEG C, and the time of each mechanical pretreatment is 5-10min.Mechanical pretreatment Effect be so that deformation appropriate occurs for wood chip, convenient for the infiltration of medical fluid.

Further, the preparation of step (2) described cooking liquor, comprising: it is molten that methanol is added in sodium hydroxide and sodium sulfite In liquid, it is uniformly mixed, obtains the cooking liquor；The concentration expressed in percentage by volume of the methanol solution is 10-30%；In the cooking liquor In, the mass percent concentration of sodium hydroxide is 2.5wt%；In the cooking liquor, the mass percent concentration of sodium sulfite is 4.23wt%。

Further, the mass ratio of the wood chip after step (2) described mechanical pretreatment and cooking liquor is 1:10-1:50, institute The time for stating immersion treatment is 1-2 days；The protective agent is anthrahydroquinone, dihydro-anthraquinone, tetrahydro-anthraquinone, 2-methylanthraquinone and more sulphur Change one of sodium, protectant quality is the 0.06-0.10% of the chip quality after the mechanical pretreatment.

Preferably, the mass ratio of the wood chip after step (2) described mechanical pretreatment and cooking liquor is 1:50.

When the mass ratio of wood chip and cooking liquor after mechanical pretreatment is 1:50, final high polymerization degree wood pulp obtained The degree of polymerization is up to 2517.

Further, it is anionic surfactant that step (2) described protective agent, which is penetrant, and the penetrant is One of neopelex, xylene monosulfonic acid and condensation sodium naphthalene sulfonate；The quality of the penetrant is the machine The 40% of the pretreated chip quality of tool.

Further, the temperature of step (2) the boiling processing is 150-170 DEG C, and the time of the boiling processing is 3-5 Hour.

Further, in step (2), the lignin content of the slurry obtained after boiling is handled can drop to 3.45 ~3.87%。

Further, the preparation of step (3) described bleaching liquid, comprising: sodium chlorite and glacial acetic acid are added to the water, mixed Uniformly obtain the bleaching liquid；In the bleaching liquid, the mass percent concentration of the sodium chlorite is 0.60%-0.80%； In the bleaching liquid, the mass percent concentration of the glacial acetic acid is 0.80-0.10%；The temperature of the bleaching is 70- 80 DEG C, the time of bleaching is 1-2h.

Further, the mass volume ratio of the slurry after step (3) described boiling and bleaching liquid is 0.37:1g/mL.

The present invention provides a kind of high polymerization degree wood pulp as made from above-mentioned preparation method.

High polymerization degree wood pulp provided by the invention, the degree of polymerization is up to 2376-2517 (DP).

A kind of preparation method of high polymerization degree wood pulp provided by the invention, specifically comprises the following steps:

(1) cooking liquor is prepared:

It is 20 ~ 40% first that sodium hydroxide, sodium sulfite (on the basis of sodium sulfite, alkali charge is 20~25%), which are used volume fraction, Alcoholic solution is dissolved, and is stirred evenly, and cooking liquor is obtained；Liquor strength is controlled by changing the dosage of wood chip, to control The degree of polymerization of slurry；

(2) pretreatment of raw material:

China fir is cut into sheet, with a thickness of 2~4 millimeters, and appropriate mechanical treatment 2 ~ 3 is carried out to wood chip using double-screw extrusion machine Time, by chip impregnation 1~2 day in cooking liquor, it is convenient for medicinal liquid osmosis；

(3) by cooking liquor obtained in step (1) together with wood chip obtained in step (2) and cellulose protective agent, bleeding agent It is added in autoclave and carries out boiling, heating rate is preferably 0.8 DEG C/min, keeps the temperature 3 when temperature reaches 150 ~ 170 degree ~5 hours, room temperature was naturally cooled to later；

(4) slurry obtained in step (3) is cleaned, discongested and is sieved；

(5) slurry in step (4) is bleached using sodium chlorite, glacial acetic acid；

(6) slurry in step (5) is cleaned using distilled water, obtains the wood pulp of high polymerization degree, Gao Baidu.

The technical principle of the preparation method of high polymerization degree wood pulp provided by the invention, as described below.

Boiling:

Under the effect of high temperature highly basic, cellulose macromolecule chain can be hydrolyzed and is broken, and become two or more short molecular chains, by original One reducing end group becomes two or more reducing end groups, this can promote the generation of peeling reaction again.If fracture Part occurs in the end section close to macromolecular chain, and generated oligosaccharide can be directly dissolved in solution.Cellulose passes through alkali Property hydrolysis after, average degree of polymerization can be remarkably decreased, and necessarily will affect the intensity and other performances of paper pulp.

Anthraquinone and the like (cellulose protective agent) is sufficiently stable in ordinary circumstance, is not easy to be oxidized, also be not easy weak Reducing agent reduction.But production 9 can be reduced in alkaline solution, 10- dihydroxy-anthracene (is also anthrahydroquinone, H₂AQ or AHQ), but AHQ is unstable, is easily oxidized agent oxidation and can generate anthraquinone.

The reducing end group of anthraquinone and carbohydrate is had an effect, by the way that reducing end group is become hydroxyl Mode inhibits the generation of peeling reaction, and anthraquinone can be reduced into AHQ at this time.Under alkaline condition, AHQ can be ionized into anthrahydroquinone Ion, then into cross exchange become oxanthrone ion again in lignin methylene quinone structure generation reacts, while oxanthrone from Son is changed into anthraquinone again, continues and redox reaction occurs for carbohydrate.During such circular response, fiber Element is protected, and yield improves, and the removal efficiency of lignin is also improved, and anthraquinone plays and Na₂The similar effect of S.Its Effect of the middle anthraquinone to lignin, mainly by the carbanion attack lignin methylene quinone structure in oxanthrone ion Methylene position, and electronics is provided by negative oxygen ion, promote the fracture of phenolic beta-aromatic ehter bond.

Bleeding agent is mainly anionic surfactant (such as dodecyl, xylene monosulfonic acid, condensation sodium naphthalene sulfonate), is answered It uses in boiling, the effect for mainly soaking, permeating and dispersing, promotes wetting of the cooking liquor to fibrous raw material, accelerate boiling The infiltration of product and other chemicals and evenly dispersed, takes off lignin in timber or non-timber and resin to promote cooking liquor It removes, moreover it is possible to play the role of dispersion resin.

Bleaching:

In bleaching process, in acid condition, sodium chlorite is reduced agent and is reduced into gaseous chlorine dioxide.Chlorine dioxide tool There is very strong oxidability, is a kind of efficient bleaching agent.Its bleaching feature be can selectively oxylignin and pigment, and Cellulose or is not seldom had damage.The whiteness of paper pulp is high after bleaching, and brightness reversion is few, and the intensity of slurry is good.

Chlorine dioxide is a kind of free radical, and the phenolic hydroxyl group that it is easy to attack lignin makes free radical, is then carried out A series of oxidation reaction.When reacting with phenolic lignin, phenol oxygen-cent red radical and other intermediary's free radicals are initially formed, this A little free radicals and chlorine dioxide form chlorous acid ester, are further transformed to o-quinone or phthalic acid etc..In addition, chlorine dioxide pair The degradation of carbohydrate, it is much smaller compared with oxygen, chlorine and hypochlorite, it is mainly shown as in acid degradation and oxidation reaction two A aspect.It is minimum to the hydrolysis of carbohydrate when PH is 4, the glucuronic acid base of oxidation reaction generation occurs at this time simultaneously Seldom.Solution PH can control using glacial acetic acid, to improve selectivity.

Compared with prior art, the invention has the advantages that and the utility model has the advantages that

(1) in the preparation method of high polymerization degree wood pulp provided by the invention, boiling processing uses anthraquinone and the like as guarantor Agent is protected, can be allowed to become generation of the carboxyl to avoid peeling reaction with the reproducibility aldehyde terminal groups of carbohydrate oxidation, it is right Cellulose and hemicellulose, which carry out protection, can be improved paper pulp yield；Sodium persulfide is as penetrant, due to the oxidation of generation Reaction and decomposition reaction, generate more vulcanized sodium, to promote the reaction of delignification；Methanol enables to reactant more living It sprinkles, and is convenient for the contact of medical fluid lignin, improve boiling efficiency；

(2) in the preparation method of high polymerization degree wood pulp provided by the invention, by controlling the ratio of wood chip and cooking liquor, discovery is poly- The right increase with liquor ratio and rise, and the optimal proportion under probing into out premised on being slurried is 1:50, and the degree of polymerization at this time is 2517, it is business slurry more than 2 times, and paste color is shallower, convenient for bleaching；

(3) in the preparation method of high polymerization degree wood pulp provided by the invention, used sodium chlorite is under the conditions of high-temperature acidic Generation chlorine dioxide can be decomposed, this is a kind of bleaching agent with very Strong oxdiative ability, being capable of selectively oxylignin and color Element, and to cellulose without or seldom damage, the whiteness of paper pulp is high after bleaching, and brightness reversion is few, and the intensity of slurry is high；

(4) preparation method of high polymerization degree wood pulp provided by the invention, changes slurrying process on the basis of industrial production Into the degree of polymerization of slurry can be improved, while improving pulp production rate and removal of impurity, good economic benefit can be brought；

(5) preparation method of high polymerization degree wood pulp provided by the invention retains the original form of fiber as far as possible, convenient for utilizing wood The Morphological Features of matter fiber itself expand application field to improve the mechanical property and optical property of cellulosic-based material；

(6) high polymerization degree wood pulp provided by the invention, in addition to can be applied to the necks such as industrial production, high molecular material research The application field of business slurry has been widened in domain, is had using the high performance material of high polymerization degree wood pulp provided by the invention preparation good Good physical property, being able to bear various machinery suppresses, and service life also increases；The high polymerization degree wood pulp has Gao Bai The characteristic of degree can be used for preparing high transparency cellophane, regulate and control film surface hole using micron order, nano-grade cellulosic Rate, it is controllable to reach mist degree, can be used for optical electron component etc..

Specific embodiment

Specific implementation of the invention is described further below in conjunction with example, but implementation and protection of the invention is not limited to This.If being that those skilled in the art can refer to prior art reality it is noted that there is the process of not special detailed description below It is existing or understanding.Reagents or instruments used without specified manufacturer, being considered as can be by the commercially available conventional products being commercially available.