Rosin supplement / cationic rosin sizing agent and preparation method thereof

Abstract

The invention provides a rosin supplement / cationic rosin sizing agent, which is composed of rosin, a rosin supplement, a cationic polymer emulsifier and a dispersant, the use amount of the rosin supplement is 5-20wt% of the total use amount of the rosin and the rosin supplement, and the rosin supplement is formed by graft copolymerization of polyethylene wax, maleic anhydride and styrene. According to the rosin supplement / cationic rosin sizing agent, maleic anhydride and styrene are added into polyethylene wax to serve as grafting monomers, grafting modification is initiated by organic peroxide to obtain grafted modified polyethylene wax, then the grafted modified polyethylene wax and rosin are mixed and melted according to a certain proportion, a cationic polymer emulsifier and a dispersing agent are added, and water-in-oil emulsion is obtained; and finally adding hot water for phase inversion. The modified polyethylene wax is used as a rosin supplement to partially replace rosin to prepare the cationic rosin sizing agent, so that the stability and the sizing effect of the product can be greatly improved, the dosage of the rosin can be greatly reduced, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of rosin-based sizing agents, in particular to a rosin extender / cationic rosin sizing agent and a preparation method thereof. Background Art

[0002] In the field of papermaking, most of the domestic internal sizing agents are rosin-based, which are mainly used to improve the water resistance of paper, prevent ink penetration, and facilitate printing. Rosin sizing agents mainly include saponified rosin sizing, anionic dispersed rosin sizing and cationic dispersed rosin sizing. Among them, cationic rosin sizing is a dispersed rosin sizing with a positive charge, which can stay on the surface of the fiber by itself, reduce the amount of aluminum sulfate, and can achieve neutral or near-neutral sizing, which has broad development and application prospects.

[0003] However, the domestic price of rosin is relatively high, and the price of rosin raw materials also fluctuates due to seasonal influences, making the cost of sizing difficult to control. Therefore, it is very urgent to develop a low-cost, seasonally unrestricted, and stable supply rosin supplement to alleviate the impact of high and volatile rosin prices. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a rosin extender / cationic rosin sizing agent and a preparation method thereof, wherein polyethylene wax is modified by grafting acid anhydride and other substances, and is used to replace part of the rosin in a papermaking sizing agent, so as to improve the physicochemical properties such as solubility, emulsifiability, pigment dispersion and lubricity, improve product stability and sizing effect, and reduce production costs, so as to solve the above-mentioned technical problems existing in the prior art.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] A rosin extender / cationic rosin sizing agent consists of rosin, rosin extender, cationic polymer emulsifier and dispersant, wherein the amount of the rosin extender is 5-22wt% of the total amount of the rosin and the rosin extender, and the rosin extender is grafted modified polyethylene wax, which is formed by graft copolymerization of polyethylene wax, maleic anhydride and styrene.

[0007] Specifically, the grafted modified polyethylene wax is prepared by the following method: using organic peroxide as an initiator, adding maleic anhydride and styrene as grafting monomers to polyethylene wax, carrying out grafting modification at a temperature of 130-180°C, reacting for 3-6 hours, and cooling to room temperature to obtain grafted modified polyethylene wax, wherein the amount of the grafted monomer is 5-12wt% of the amount of polyethylene wax.

[0008] Preferably, a polyethylene wax having a molecular weight (Mn) of 2000-5000 is used, more preferably 2500-4500, most preferably 3000-4000.

[0009] The organic peroxide is selected from at least one of benzoyl peroxide, dibenzoyl oxide, tert-butyl peroxide and di-tert-butyl peroxide, and the added amount is 0.3-2wt% of the amount of the polyethylene wax.

[0010] The graft monomers are composed of maleic anhydride and styrene, wherein the amount of maleic anhydride is not less than 50wt% of the total amount of the graft monomers. Preferably, the amount of maleic anhydride is 50-80wt% of the total amount of the graft monomers, more preferably 60-75wt%, and most preferably 65-70wt%.

[0011] The cationic polymer emulsifier can be an emulsifier commonly used in the art, preferably a composite cationic emulsifier composed of fatty alcohol polyoxyethylene ether and polyamide polyamine epichlorohydrin. In the composite cationic emulsifier, the mass ratio of the two is fatty alcohol polyoxyethylene ether: polyamide polyamine epichlorohydrin = 1:1-3.

[0012] The dispersant is selected from at least one of sodium methylene dinaphthalene sulfonate, disodium methylene dinaphthalene sulfonate and sodium dodecylbenzene sulfonate.

[0013] The amount of the cationic polymer emulsifier and dispersant added can be adjusted according to the emulsification and dispersion of the mixture of rosin and grafted modified polyethylene wax. The ratio of raw materials, melting temperature, dispersion speed, properties of grafted modified polyethylene wax, etc. will affect the actual effect of emulsification and dispersion. Preferably, the amount of the cationic polymer emulsifier is 10-30wt% of the total amount of rosin and rosin extender, and the amount of the dispersant is 3-8wt% of the total amount of rosin and rosin extender.

[0014] Preferably, the amount of the rosin extender is 10-20wt% of the total amount of rosin and the rosin extender; more preferably, the amount of the rosin extender is 12-18wt% of the total amount of rosin and the rosin extender. The optimal amount of the rosin extender is 14-16wt% of the total amount of rosin and the rosin extender.

[0015] The present invention further provides a method for preparing the above-mentioned rosin extender / cationic rosin sizing agent, comprising the following steps:

[0016] S1. Using organic peroxide as an initiator, maleic anhydride and styrene are added to polyethylene wax as grafting monomers, and grafting modification is carried out at a temperature of 130-180°C for 3-6 hours, and then cooled to room temperature to obtain grafted modified polyethylene wax, i.e., rosin extender;

[0017] S2, add rosin and rosin extender into the reaction kettle, heat to 120-150°C, wait for the rosin and rosin extender to be completely melted, start stirring to mix the materials evenly, slowly add 90-95°C cationic polymer emulsifier and dispersant to obtain a viscous water-in-oil emulsion;

[0018] S3, adding hot water at 80-90° C. to promote phase inversion, obtaining a white oil-in-water emulsion, rapidly cooling and reducing the rotation speed, adding water to adjust the solid content to obtain the rosin extender / cationic rosin sizing agent.

[0019] Preferably, the stirring speed of step S2 is 500-800 r / min, and the addition time of the cationic polymer emulsifier lasts for 20-30 min.

[0020] Preferably, the phase inversion step in step S3 is completed under high-speed stirring, the stirring speed is 1000-1200 r / min, and the hot water addition time lasts for 20-30 min.

[0021] The inventor unexpectedly discovered that the use of grafted modified polyethylene wax as a rosin supplement to partially replace rosin to prepare a cationic rosin sizing agent can unexpectedly significantly improve the stability and sizing effect of the product. The specific principle is not very clear, but it is speculated that it may be due to the significant improvement in the polarity of the product after grafting on the polyethylene wax after modification. The inventor further discovered that the effect of directly copolymerizing and grafting maleic anhydride and styrene on polyethylene wax cannot be obtained by grafting maleic anhydride or styrene alone, or simply mixing the two separately grafted products after the reaction is completed. It is speculated that the copolymerization grafting of the two produces an unexpected synergistic effect. Based on the above findings, the present invention is completed.

[0022] Compared with the prior art, the present invention creatively adopts maleic anhydride and styrene to carry out graft copolymerization modification on polyethylene wax, and the obtained modified polyethylene wax is used as a rosin supplement to partially replace rosin to prepare a cationic rosin sizing agent, which can greatly improve the stability and sizing effect of the product, thereby greatly reducing the amount of rosin used and reducing production costs, and has important market value. DETAILED DESCRIPTION

[0023] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only used as examples, but are not used to limit the scope of the present invention. Those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalent solutions, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0024] The instruments or raw materials in the present invention without indicating the manufacturer are all conventional commercial instruments or raw materials.

[0025] In the examples, polyethylene wax with a molecular weight (Mn) of 3400-3600 is used.

[0026] The cationic polymer emulsifier of the present invention can be an emulsifier commonly used in the art, such as cationic starch, cationic etherified starch, fatty alcohol polyoxyethylene ether, polydimethyldiallyl ammonium chloride, polyamide polyamine epichlorohydrin, cationic acrylate emulsifier, etc. Different emulsifiers and their dosages have a certain influence on the stability of the final sizing agent, and can be selected and adjusted according to actual conditions.

[0027] As a preferred embodiment, the cationic polymer emulsifier is compounded by fatty alcohol polyoxyethylene ether and polyamide polyamine epichlorohydrin. The preferred compounding ratio is a mass ratio of fatty alcohol polyoxyethylene ether: polyamide polyamine epichlorohydrin of 1:1-3. The sizing agent prepared by using the composite cationic polymer emulsifier with the above ratio has better stability and sizing performance.

[0028] Among them, the fatty alcohol polyoxyethylene ether can be used separately or in combination with AEO-3, AEO-7, AEO-9, AEO-15 and other types of fatty alcohol polyoxyethylene ether emulsifiers. In the following examples, AEO-9 fatty alcohol polyoxyethylene ether is used unless otherwise specified.

[0029] Polyamide polyamine epichlorohydrin can be a commercially available product. In the following embodiments, it is prepared by the following method: add diethylenetriamine to a three-necked flask, heat to 120°C in an oil bath, then add adipic acid under stirring, continue to heat to 160-180°C, keep warm for 4 hours, and stop heating. When the temperature of the reactant drops to 100°C, dilute with water to a solid content of 50%, and a 50% mass fraction polyamide polyamine prepolymer can be obtained; take the above polyamide polyamine prepolymer, stir and dilute with water to 25% mass fraction, slowly add epichlorohydrin under stirring, and control the dropwise addition time to 5min as much as possible, heat to 70°C and react for 70min, and immediately add dilute sulfuric acid to adjust the pH to 3-4 after the reaction is completed, and dilute to a solid content of 12.5% ​​for storage. The molar ratio of diethylenetriamine to adipic acid is 1.02:1, and the molar ratio of polyamide polyamine prepolymer to epichlorohydrin is 1:1.

[0030] Unless otherwise mentioned, the detection indicators involved in the embodiments of the present invention are detected by conventional detection methods in the art.

[0031] Example 1

[0032] 1) Preparation of rosin extender:

[0033] Add 1.2 parts of benzoyl peroxide, 7 parts of maleic anhydride and 3 parts of styrene to 100 parts of polyethylene wax, carry out graft modification at a temperature of 170°C, the reaction time is 5 hours, and then cool to room temperature to obtain graft modified polyethylene wax;

[0034] 2) Preparation of rosin extender / cationic rosin sizing agent:

[0035] Take 16 parts of grafted modified polyethylene wax and add them to the reactor together with 84 parts of rosin. Heat the two materials to 150°C and wait until they are completely melted, then start stirring to mix the materials evenly. Add 20 parts of a 95°C composite cationic polymer emulsifier (formed by compounding fatty alcohol polyoxyethylene ether and polyamide polyamine epichlorohydrin in a mass ratio of 1:2) and 5 parts of sodium methylene dinaphthalene sulfonate under high-speed stirring at a speed of 800 rpm, and add for 30 minutes to obtain an oil-in-water viscous emulsion. Further increase the stirring speed to 1200 rpm, add 90°C hot water to promote phase inversion, and add for 30 minutes to obtain a white water-in-oil emulsion. Rapidly cool down and reduce the speed, add an appropriate amount of water, and adjust the solid content to obtain the rosin extender / cationic rosin sizing agent.

[0036] Embodiment 2-14

[0037] Different amounts of rosin extender-grafted modified polyethylene wax were used to replace rosin, and other preparation steps and process conditions were the same as those in Example 1. The specific replacement amounts are shown in the following table:

[0038] Table 1 Amount of some raw materials used in Examples 2-14

[0039]

[0040]

[0041] Embodiment 15

[0042] 1) Preparation of rosin extender:

[0043] Add 2 parts of dibenzoyl oxide, 2.5 parts of maleic anhydride and 2.5 parts of styrene to 100 parts of polyethylene wax, carry out graft modification at a temperature of 130° C., the reaction time is 6 hours, and then cool to room temperature to obtain graft modified polyethylene wax;

[0044] 2) Preparation of rosin extender / cationic rosin sizing agent:

[0045] Take 16 parts of grafted modified polyethylene wax and add them to the reactor together with 84 parts of rosin. Heat the two materials to 120°C and wait until they are completely melted, then start stirring to mix the materials evenly. Add 10 parts of a 90°C composite cationic polymer emulsifier (formed by compounding fatty alcohol polyoxyethylene ether and polyamide polyamine epichlorohydrin in a mass ratio of 1:1) and 8 parts of disodium methylene dinaphthalene sulfonate under high-speed stirring at a speed of 500 rpm, and add for 20 minutes to obtain an oil-in-water viscous emulsion. Further increase the stirring speed to 1000 rpm, add 80°C hot water to promote phase inversion, and add for 20 minutes to obtain a white water-in-oil emulsion. Rapidly cool down and reduce the speed, add an appropriate amount of water, and adjust the solid content to obtain the rosin extender / cationic rosin sizing agent.

[0046] Example 16

[0047] 1) Preparation of rosin extender:

[0048] Add 0.5 parts of tert-butyl peroxide, 7 parts of maleic anhydride and 5 parts of styrene to 100 parts of polyethylene wax, carry out graft modification at a temperature of 180°C for 3 hours, and cool to room temperature to obtain graft modified polyethylene wax;

[0049] 2) Preparation of rosin extender / cationic rosin sizing agent:

[0050] Take 10 parts of grafted modified polyethylene wax and add them to the reactor together with 90 parts of rosin. Heat the two materials to 140°C until they are completely melted, then stir to mix the materials evenly. Add 30 parts of 93°C composite cationic polymer emulsifier (formed by compounding fatty alcohol polyoxyethylene ether and polyamide polyamine epichlorohydrin in a mass ratio of 1:3) and 3 parts of sodium dodecylbenzene sulfonate under high-speed stirring at a speed of 600 rpm, and add for 25 minutes to obtain a viscous water-in-oil emulsion. Further increase the stirring speed to 1100 rpm, add 85°C hot water to promote phase inversion, and add for 25 minutes to obtain a white water-in-oil emulsion. Rapidly cool down and reduce the speed, add an appropriate amount of water, and adjust the solid content to obtain the rosin extender / cationic rosin sizing agent.

[0051] Comparative Example 1

[0052] No grafted modified polyethylene wax is added, that is, 100% rosin is used, and the rest is the same as in Example 1. The specific steps are as follows: 100 parts of rosin are added to a reactor, heated to 150°C until the rosin is completely melted, and 20 parts of a 95°C composite cationic polymer emulsifier (formed by compounding fatty alcohol polyoxyethylene ether and polyamide polyamine epichlorohydrin in a mass ratio of 1:2) and 5 parts of sodium methylene dinaphthalene sulfonate are added under high-speed stirring at a speed of 800 rpm, and the addition time lasts for 30 minutes to obtain an oil-in-water viscous emulsion. Further increase the stirring speed to 1200 rpm, add 90°C hot water to promote phase inversion, and the addition time lasts for 30 minutes to obtain a water-in-oil white emulsion, quickly cool down and reduce the speed, add an appropriate amount of water, and adjust the solid content to obtain a cationic rosin sizing agent.

[0053] Comparative Example 2

[0054] Maleic anhydride was grafted alone without adding styrene, and the rest was the same as in Example 1. The specific process is as follows:

[0055] 1) Preparation of rosin extender:

[0056] Add 1.2 parts of benzoyl peroxide and 7 parts of maleic anhydride to 100 parts of polyethylene wax, carry out graft modification at a temperature of 170°C, the reaction time is 5 hours, and then cool to room temperature to obtain graft modified polyethylene wax;

[0057] 2) Preparation of rosin extender / cationic rosin sizing agent, same as in Example 1.

[0058] Comparative Example 3

[0059] Styrene was grafted alone without adding maleic anhydride, and the rest was the same as in Example 1. The specific process is as follows:

[0060] 1) Preparation of rosin extender:

[0061] Add 1.2 parts of benzoyl peroxide and 3 parts of styrene to 100 parts of polyethylene wax, carry out graft modification at a temperature of 170°C, the reaction time is 5 hours, and then cool to room temperature to obtain graft modified polyethylene wax;

[0062] 2) Preparation of rosin extender / cationic rosin sizing agent, same as in Example 1.

[0063] Comparative Example 4

[0064] The grafted modified polyethylene waxes prepared in Comparative Examples 3 and 4 were mixed and used to prepare a rosin extender / cationic rosin sizing agent. The specific process is as follows:

[0065] Take 11.2 parts of the grafted modified polyethylene wax prepared in Comparative Example 2 and 4.8 parts of the grafted modified polyethylene wax prepared in Comparative Example 3, and add them together with 84 parts of rosin into the reactor. Heat the three materials to 150°C until they are completely melted, and then stir to mix the materials evenly. Add 20 parts of a 95°C composite cationic polymer emulsifier (formed by compounding fatty alcohol polyoxyethylene ether and polyamide polyamine epichlorohydrin in a mass ratio of 1:2) and 5 parts of sodium methylene dinaphthalene sulfonate under high-speed stirring at a speed of 800 rpm, and add for 30 minutes to obtain a viscous emulsion of water in oil. Further increase the stirring speed to 1200 rpm, add 90°C hot water to promote phase inversion, and add for 30 minutes to obtain a white emulsion of oil in water, quickly cool down and reduce the speed, add an appropriate amount of water, and adjust the solid content to obtain the rosin extender / cationic rosin sizing agent.

[0066] Application Examples

[0067] The sizing agents of the examples and comparative examples were applied to paper pulp for internal sizing, with an addition amount of 9 kg / t paper. The specific process is as follows:

[0068] Designed papermaking weight 100g / m 2 .

[0069] Process: pulp 85% + aluminum sulfate + rosin glue + talc 15% + CPAM (200ppm)

[0070] Sizing agent addition amount 9kg / t paper (wet / dry, each sample is added at 35% solid content)

[0071] According to the above process, the pH value of the blank pulp was adjusted to about 5.0 with a 30% aluminum sulfate solution, and then the sizing agent was added. After stirring for 1 minute, talcum powder was added, and after stirring for 1 minute, a retention agent was added. After 1 minute, the prepared pulp was removed, and the sheet was made with a 73-62 semi-automatic paper sheet former, and after being pressed with a 73-50 standard paper sheet press, the paper sample was dried with a glazing machine, and the 1-minute Cobb value of the paper sample was tested. Each sample was tested in parallel 3 times to obtain the average value. The test results are shown in Table 1.

[0072] Table 2 Test results of water absorption performance of paper after internal sizing with different sizing agents

[0073]

[0074]

[0075] From the comparison of water absorption performance of hand-made paper samples, the use of grafted modified polyethylene wax as a rosin supplement to partially replace rosin to prepare cationic rosin sizing agent can greatly improve the water resistance of the product. Single grafting of maleic anhydride or styrene, or simply mixing the two single grafted products after the reaction, did not have a good effect on promoting water resistance, indicating that the copolymerization grafting of the two produced a significant synergistic effect.

[0076] It should be understood by those skilled in the art that the above embodiments are only examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be deformed or modified in any way without departing from the principles.

Claims

1. A rosin extender / cationic rosin sizing agent, characterized in that: The invention is composed of rosin, rosin extender, cationic polymer emulsifier and dispersant, wherein the amount of rosin extender is 5-22wt% of the total amount of rosin and rosin extender, the rosin extender is grafted modified polyethylene wax, and the grafted modified polyethylene wax is grafted copolymerized with polyethylene wax, maleic anhydride and styrene.

2. The rosin extender / cationic rosin sizing agent according to claim 1, characterized in that: The grafted modified polyethylene wax is prepared by the following method: using organic peroxide as an initiator, adding maleic anhydride and styrene as grafting monomers into polyethylene wax, carrying out grafting modification at a temperature of 130-180° C., reacting for 3-6 hours, and cooling to room temperature to obtain the grafted modified polyethylene wax, wherein the amount of the grafted monomer is 5-12wt% of the amount of the polyethylene wax.

3. The rosin extender / cationic rosin sizing agent according to claim 1, characterized in that: The organic peroxide is selected from at least one of benzoyl peroxide, dibenzoyl oxide, tert-butyl peroxide and di-tert-butyl peroxide.

4. The rosin extender / cationic rosin sizing agent according to claim 1, characterized in that: The amount of maleic anhydride in the graft monomer is not less than 50 wt % of the total amount of the graft monomer.

5. The rosin extender / cationic rosin sizing agent according to claim 4, characterized in that: The amount of maleic anhydride in the graft monomer is 60-75 wt % of the total amount of the graft monomer.

6. The rosin extender / cationic rosin sizing agent according to claim 1, characterized in that: The cationic polymer emulsifier is a composite cationic emulsifier composed of fatty alcohol polyoxyethylene ether and polyamide polyamine epichlorohydrin.

7. The rosin extender / cationic rosin sizing agent according to claim 1, characterized in that: The dispersant is selected from at least one of sodium methylene dinaphthalene sulfonate, disodium methylene dinaphthalene sulfonate and sodium dodecylbenzene sulfonate.

8. The rosin extender / cationic rosin sizing agent according to claim 1, characterized in that: The amount of the rosin extender is 14-16 wt % of the total amount of rosin and the rosin extender.

9. The method for preparing the rosin extender / cationic rosin sizing agent according to claims 1-8, characterized in that: The steps include: S1. Using organic peroxide as an initiator, maleic anhydride and styrene are added to polyethylene wax as grafting monomers, and grafting modification is carried out at a temperature of 130-180°C for 3-6 hours, and then cooled to room temperature to obtain grafted modified polyethylene wax, i.e., rosin extender; S2, add rosin and rosin extender into the reaction kettle, heat to 120-150°C, wait for the rosin and rosin extender to be completely melted, start stirring to mix the materials evenly, slowly add 90-95°C cationic polymer emulsifier and dispersant to obtain a viscous water-in-oil emulsion; S3, adding hot water at 80-90° C. to promote phase inversion, obtaining a white oil-in-water emulsion, rapidly cooling and reducing the rotation speed, adding water to adjust the solid content to obtain the rosin extender / cationic rosin sizing agent.

10. The method according to claim 9, characterized in that The stirring speed of step S2 is 500-800r / min, and the cationic polymer emulsifier is added for 20-30min; the phase inversion step of step S3 is completed under high-speed stirring, the stirring speed is 1000-1200r / min, and the hot water is added for 20-30min.

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