CN103469688B - The method of paper strengthening agent is prepared in a kind of corncob modification - Google Patents

Abstract

A method for preparing a paper strengthening agent by modifying corncobs, comprising the following steps: corncobs are pulverized to obtain corncob powder below 80 mesh; corncob powder is treated in glacial acetic acid and sodium chlorite aqueous solution; The product is cooled, filtered, and washed with water until the washing liquid is not acidic, and a white intermediate product is obtained; the white intermediate product is added into water to make a suspension of 1wt% to 5wt%, at a temperature of 40°C and 0.005 parts by weight of the white intermediate product is added FeSO ₄ As a catalyst, add 30% H ₂ O ₂ liquid, so that the concentration of H ₂ O ₂ in the reaction solution is 0.3wt% to 0.9wt%; use sodium hydroxide and/or hydrochloric acid to adjust the concentration of the reaction solution The pH value is 4.5-5.5, and the reaction time is controlled at 30min-70min; after the reaction is completed, the paper strengthening agent is obtained by filtering and washing.

Description

A kind of corncob modification prepares the method for paper strengthening agent

technical field

The invention relates to a paper strengthening agent in papermaking technology, in particular to a production method for synthesizing a paper strengthening agent with corncobs as a raw material, and in particular to a corncob modification method used as a paper strengthening agent.

Background technique

my country is a big agricultural country with abundant plant fiber resources. The corn cob is the fruit axis of the corn ear after the kernel is removed. Corn production is 110-130 million tons per year, and 20 million tons of corn cobs can be produced as a by-product. However, corn cobs, as a kind of agricultural waste, are mostly used as fuel at present, causing a lot of waste. At present, domestic and foreign studies have been carried out around the deep processing and comprehensive utilization of corn cobs, and a series of new ways for comprehensive processing of corn cobs have been developed. With the continuous enhancement of my country's scientific and technological strength, the field of deep processing of corn cobs has been continuously expanded. At present, many products have been industrialized, making this waste material a resource utilization. With the increase of corn production, the amount of corncobs has been greatly increased. Continued research and development of renewable corncobs to prepare biodegradable materials or chemicals is of great significance to the high value of plant resources and environmental protection.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a paper strengthening agent by modifying corn cobs. According to the chemical groups contained in the corn cobs, targeted modification can enhance the strength of paper.

In order to solve the above-mentioned technical problems, a kind of corn cob modification provided by the invention prepares the method for paper strengthening agent, at least comprises the following steps:

1) Corncob pulverization makes corncob powder below 80 mesh;

2) using glacial acetic acid of 10-25wt% of the corncob powder and 10-25wt% of sodium chlorite to prepare the first aqueous solution, and treating the corncob powder in the first aqueous solution at a temperature of 75-80°C for 50 ~70 minutes;

3) After the treatment in the previous step, add 10-25 wt% glacial acetic acid and 10-25 wt% sodium chlorite to the corncob powder, and continue the treatment at a temperature of 75-80° C. for 50-70 minutes;

4) cooling, filtering, and washing with water until the washing liquid is not acidic after the intermediate processed in the above step, and a white intermediate product is obtained;

₅ ) Add the white intermediate product to water to make a suspension of 1wt% to 5wt%, and add 30 _% H2O2 at a temperature of 40°C and add 0.005 parts by weight of _FeSO4 to the white intermediate product as a catalyst solution, so that the concentration of H2O2 in the reaction solution is 0.3wt% to _0.9wt %; the pH value of the reaction solution is adjusted to 4.5 to 5.5 with _sodium hydroxide and/or hydrochloric acid, and the reaction time is controlled at 30min to 70min;

6) After the reaction is finished, the paper strengthening agent is prepared by filtering and washing.

Further, the method for preparing a paper strengthening agent by modifying corncobs is characterized in that: the filtrate obtained by filtering in step 4) is reused in step 2).

Beneficial effects brought by the present invention: H ₂ O ₂ +FeSO ₄ oxidation system is used to oxidize the hydroxyl group in the corncob cellulose to carboxyl group, when the paper strengthening agent is added to the paper pulp, it can strengthen the pulp fiber The binding force, thereby improving the physical strength of the paper. Using agricultural waste corncobs as raw materials, the comprehensive utilization of renewable agricultural waste resources is realized.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute improper limitations to the present invention. In the attached picture:

The trend diagram of the influence of the H2O2 concentration _on the folding endurance in the modification process of Fig. ₁ ;

The trend diagram of the influence of _{H2O2concentration} on tensile index in the modification process of Fig. ₂ ;

Figure ₃ is a trend diagram of the impact of H2O2 concentration _on the burst index in the modification process;

Fig. 4. _The trend diagram of the effect of the concentration of H2O2 used in the modification process _on the tear index.

detailed description

Embodiment 1: sieve the corncob after pulverizing to obtain the corncob powder below 80 orders; use the glacial acetic acid of described corncob powder 25wt% and the sodium chlorite of 25wt% to be mixed with the first aqueous solution, corncob powder is in Treat in the first aqueous solution at a temperature of 75°C for 60 minutes; continue to add 10wt% glacial acetic acid and 10wt% sodium chlorite to the corncob powder, and continue to process the corncob powder for 50 minutes at a temperature of 80°C; The obtained intermediate is cooled, filtered, and washed with water until the lotion is not acidic to obtain a white intermediate; the white intermediate is added to water to make a 1wt% suspension, and the white intermediate is added at a temperature of 40° C. 0.005 parts by weight of FeSO ₄ As a catalyst, add 30% H ₂ O ₂ liquid, so that the concentration of H ₂ O ₂ in the reaction solution is 0.3 wt %; adjust the pH of the reaction solution with sodium hydroxide and/or hydrochloric acid The value is between 4.5 and 5.5, and the reaction time is controlled at 30 minutes; after the reaction is completed, the paper strengthening agent is obtained by filtering and washing. The poplar kraft pulp is thawed with water and beaten to 40°SR, diluted to a concentration of 2‰, adding 0.25wt% aluminum sulfate of dry pulp, adjusting the pH value of the slurry to 5, and adding 1wt% of dry pulp for this implementation After the paper strengthening agent prepared by example, after stirring evenly, according to the preparation of the national standard pulp laboratory paper sheet, the conventional sheet former method (QB/T3703-99) is used to take the paper sheet of quantitative 60g/m ² . After aging at 105°C for 20 minutes, balance the moisture for 24 hours under constant temperature and humidity conditions, and measure its strength.

Embodiment 2: sieve the corncob after pulverizing and make the corncob powder below 80 orders; Be formulated with the first aqueous solution with the glacial acetic acid of described corncob powder 10wt% and the sodium chlorite of 10wt%, corncob powder is in Treat in the first aqueous solution at a temperature of 80°C for 50 minutes; continue to add 25wt% of glacial acetic acid and 25wt% sodium chlorite to the corncob powder, and continue to process the corncob powder at a temperature of 75°C for 70 minutes; The obtained intermediate is cooled, filtered, and washed with water until the lotion is not acidic to obtain a white intermediate; the white intermediate is added to water to make a 2wt% suspension, and the white intermediate is added at a temperature of 40° C. 0.005 parts by weight of FeSO ₄ As a catalyst, add 30% H ₂ O ₂ liquid, so that the concentration of H ₂ O ₂ in the reaction solution is 0.6 wt %; adjust the pH of the reaction solution with sodium hydroxide and/or hydrochloric acid The value is between 4.5 and 5.5, and the reaction time is controlled at 45 minutes; after the reaction is completed, the paper strengthening agent is obtained by filtering and washing. Dissolve poplar kraft pulp with water and beat to 40°SR, dilute to a concentration of 2‰, adjust the pH value of the slurry to 7, add 4wt% dry pulp of the paper strengthening agent prepared in this embodiment, and stir evenly According to the national standard pulp laboratory paper preparation conventional paper former method (QB/T3703-99), the quantitative 60g/ ^m2 paper was taken. After aging at 105°C for 20 minutes, balance the moisture for 24 hours under constant temperature and humidity conditions, and measure its strength.

Embodiment 3: sieve corncob after pulverizing and make the corncob powder below 80 orders; Be formulated with the first aqueous solution with the glacial acetic acid of described corncob powder 20wt% and the sodium chlorite of 20wt%, corncob powder is in Treat in the first aqueous solution at a temperature of 78°C for 60 minutes; continue to add glacial acetic acid of 20wt% of the corncob powder and 20wt% sodium chlorite to prepare a second aqueous solution, and continue to process the corncob powder at a temperature of 77°C Treat for 60 minutes; the intermediate obtained after the treatment is cooled, filtered, and washed with water until the washing liquid is not acidic, and a white intermediate is obtained; the white intermediate is added to water to make a 5wt% suspension. 0.005 parts by weight of the white intermediate product FeSO ₄ As a catalyst, add 30% H ₂ O ₂ liquid, so that the concentration of H ₂ O ₂ in the reaction solution is 0.9 wt %; use sodium hydroxide and/or hydrochloric acid The pH value of the reaction solution is adjusted to 4.5-5.5, and the reaction time is controlled at 70 minutes; after the reaction is completed, the paper strengthening agent is obtained by filtering and washing. Dissolve poplar kraft pulp with water and beat to 40°SR, dilute to a concentration of 2‰, adjust the pH value of the slurry to 9, add 3wt% dry pulp of the paper strengthening agent prepared in this embodiment, and stir evenly According to the national standard pulp laboratory paper preparation conventional paper former method (QB/T3703-99), the quantitative 60g/ ^m2 paper was taken. After aging at 105°C for 20 minutes, balance the moisture for 24 hours under constant temperature and humidity conditions, and measure its strength.

Embodiment 4: sieve after corn cob pulverizes and make the corn cob powder below 80 orders; Be formulated with the glacial acetic acid of described corn cob powder 25wt% and the sodium chlorite of 25wt% aqueous solution, corn cob powder is at 75 ℃ Process in the solution at high temperature for 65 minutes; continue to add the glacial acetic acid of 25wt% of the corncob powder and 25wt% sodium chlorite, and continue to process the corncob powder for 50 minutes at a temperature of 80°C; the intermediate obtained after processing The product is cooled, filtered, and washed with water until the lotion is not acidic, and a white intermediate product is obtained; the white intermediate product is added to water to make a 5wt% suspension, and the white intermediate product is added at a temperature of 40° C. and 0.005 parts by weight of the white intermediate product FeSO ₄ As a catalyst, add 30% H ₂ O ₂ liquid, so that the concentration of H ₂ O ₂ in the reaction solution is 0.9wt%; adjust the pH value of the reaction solution at 4.5 with sodium hydroxide and/or hydrochloric acid ~5.5, the reaction time is controlled at 70 minutes; after the reaction is completed, the paper strengthening agent is obtained by filtering and washing. Dissolve poplar kraft pulp with water and beat to 40°SR, dilute to a concentration of 2‰, adjust the pH value of the slurry to 9, add 1wt% dry pulp of the paper strengthening agent prepared in this embodiment, and stir evenly According to the national standard pulp laboratory paper preparation conventional paper former method (QB/T3703-99), the quantitative 60g/ ^m2 paper was taken. After aging at 105°C for 20 minutes, balance the moisture for 24 hours under constant temperature and humidity conditions, and measure its strength.

Comparative Example Example: after dissolving poplar kraft pulp with water, beating to 40 ° SR, diluting to a concentration of 2 ‰, adjusting the pH value of the slurry to 5, and stirring evenly, according to the preparation of national standard pulp laboratory paper Conventional sheet former method (QB/ ^T3703-99 ) draws paper sheet with quantitative 60g/m2. After aging at 105°C for 20 minutes, balance the moisture for 24 hours under constant temperature and humidity conditions, and measure its strength. The paper product that each embodiment and comparative example obtains, after testing performance is as follows:

Under the condition of fixed oxidation time of 60 minutes, the modified product obtained by changing the oxidation concentration of H ₂ O ₂ is obtained by dissolving poplar kraft pulp with water, beating to 40°SR, diluting to a concentration of 2‰, and adjusting the pH value of the pulp To 5, add dry pulp 1wt% the present invention to change H ₂ O oxidized concentration _The paper strengthening agent that each embodiment makes, after stirring evenly, press the conventional paper former method (QB of the preparation of national standard pulp laboratory paper) / ^T3703-99 ) take paper sheets with a weight of 60g/m2. After aging at 105°C for 20 minutes, balance the moisture for 24 hours under constant temperature and humidity conditions, and measure its strength. The influence of different H ₂ O ₂ oxidation concentrations on paper properties was analyzed.

Figure 1 shows the influence trend of H ₂ O ₂ oxidation concentration on paper folding endurance. With the increase of H ₂ O ₂ oxidation concentration, the folding strength of the paper added with oxidized cellulose strengthening agent with an oxidation time of 60 minutes increased gradually, but the growth rate was fast at first and then slow. After adding the reinforcing agent, the intermolecular hydrogen bonding ability becomes stronger, the bonding force between fibers increases, and the folding resistance increases; if it is peroxidized, carboxyl groups are generated, and the glucose ring is cracked, which affects the bonding between fibers.

Figure 2 shows the influence trend of H ₂ O ₂ oxidation concentration on paper tensile index. With the increase of H ₂ O ₂ oxidation concentration, the tensile index of paper increases continuously.

Figure 3 shows the influence trend of H ₂ O ₂ oxidation concentration on paper burst index. With the increase of H ₂ O ₂ oxidation concentration, the burst index of paper increases gradually.

Figure 4 shows the influence trend of H ₂ O ₂ oxidation concentration on paper tear index. With the increase of H ₂ O ₂ oxidation concentration, the paper tear index showed a downward trend.

The results showed that: with the increase of the concentration of oxidized hydrogen peroxide and the prolongation of the reaction time of the paper strengthening agent prepared from corncobs, the dry tensile strength of the paper showed an upward trend; the burst index increased, but not as obviously as the increase of the dry tensile strength; The folding resistance showed a significant upward trend, and the tearing degree showed a downward trend. As the oxidation time increases, the oxygen content gradually increases, the hydrogen bonds between fibers increase, the binding force increases, and the folding and bursting resistance also increase. However, with the increase of oxidation time, the degree of polymerization of the modified corn cob decreased, which made the tear index decrease continuously. Preferably, the concentration of hydrogen peroxide is 0.7%-0.9%, and the oxidation time is 40-70 minutes, which has good technical effect.

In the present invention, paper weight, tensile index, tear index, burst index, and folding endurance are respectively according to the mensuration of national standard paper and cardboard quantitative (GB/T451.2-2002), the mensuration constant of paper and cardboard tensile strength. Rapid tensile method (100mm/min) (GB/T22898-2008), determination of tearing degree of paper and cardboard (GB/T455-2002), determination of paper bursting strength (GB/T454-2002), paper and cardboard Determination of folding endurance (GB/T457-2008) method for testing.

Apparently, the present invention is not limited to the above preferred embodiments, but can also be transformed and improved in various forms within the spirit of the claims and description of the present invention, so as to solve the same technical problems and obtain expected technical effects. restate. All solutions that a person of ordinary skill in the art can directly or associate from the content disclosed in the present invention, as long as they are within the spirit defined in the claims, also belong to the protection scope of the present invention.

Claims (2)

1. a method for paper strengthening agent is prepared in corncob modification, it is characterized in that, at least comprises the following steps:

1) corncob pulverizes the maize cob meal of below obtained 80 orders;

2) be mixed with first aqueous solution with the described glacial acetic acid of maize cob meal 10 ~ 25wt% and the sodium chlorite of 10 ~ 25wt%, maize cob meal processes 50 ~ 70 minutes at 75 ~ 80 DEG C of temperature in described first aqueous solution;

3) after upper step process, then add the described glacial acetic acid of maize cob meal 10 ~ 25wt% and the sodium chlorite of 10 ~ 25wt%, at 75 ~ 80 DEG C of temperature, continue process 50 ~ 70 minutes;

4) intermediate after upper step process cools, filter, be washed with water to washing lotion not in acid, obtained white intermediate product;

5) white intermediate product is added to the water, makes the suspension of 1wt% ~ 5wt%, at 40 DEG C of temperature and the FeSO adding described white intermediate product 0.005 weight portion ₄as under catalysts conditions, add the H of 30% ₂o ₂liquid, makes H ₂o ₂concentration in reactant liquor is 0.3wt% ~ 0.9wt%; Regulate the pH value of reactant liquor 4.5 ~ 5.5 with NaOH and/or hydrochloric acid, the reaction time controls at 30min ~ 70min;

6), after reaction terminates, after filtration, obtained paper strengthening agent is washed.

2. the method for paper strengthening agent is prepared in corncob modification according to claim 1, it is characterized in that: step 4) in filter the filtered fluid that obtains and be back to step 2) in.