A preparation method of rosin resin

Abstract

The present application provides a method for preparing rosin resin, which belongs to the field of rosin processing. The preparation method comprises the following steps: (1) putting rosin into a reactor, heating to 180-200°C under inert gas protection and melting; (2) adding a catalyst of 0.01-0.5% by weight of rosin and a polyol of 6-12% by weight of rosin, and reacting at 200-290°C for 6-15 hours; (3) evacuating until the rosin resin reaches a specified acid value; (4) adding an antioxidant of 0.01-0.5% by weight of rosin, stirring evenly, and discharging to obtain rosin resin. The present application adds a post-treatment agent, so that the prepared rosin resin has less effect on cell activity, shows excellent cell compatibility, and has good weather resistance, and has important application value in the medical field.

Description

Technical Field

[0001] The invention belongs to the field of rosin processing, and particularly relates to a method for preparing rosin resin. Background Art

[0002] Rosin is a natural plant-derived resource, primarily composed of resin acids. Due to its unique chemical structure and extensive biological activity, it is widely valued and commonly used in coatings, inks, adhesives, and other fields. The presence of carboxyl groups and conjugated double bonds in rosin molecules imparts a certain degree of reactivity, but this also presents significant drawbacks in its application, such as a high acid value and poor acid and alkali resistance. To expand its applications, rosin has been modified in various ways. The carboxyl groups and double bonds in rosin can be exploited for esterification and addition reactions to produce rosin resins with varying physical and chemical properties, such as hydrogenated rosin, disproportionated rosin, and polymerized rosin. Hydrogenated rosin is produced by hydrogenating the conjugated double bonds of the tertiary acid to form dihydrorosin or perhydrorosin; disproportionated rosin is produced by disproportionating the conjugated double bonds of the tertiary acid to form hydrogenated resin acids and dehydrogenated tertiary acids; and polymerized rosin is produced by polymerizing the double bonds in the rosin, destroying the conjugated double bonds within the tertiary acid, thereby improving its stability, lightening its color, and reducing its oxygen absorption.

[0003] Rosin resin prepared from rosin and its derivatives has the characteristics of light color, low acid value and good weather resistance. It can be used in coatings, inks, adhesives and other fields. However, the residual resin acid, small molecule free acid and monorosin acid ester produced by esterification reaction in rosin resin are potential contact allergens, which to a certain extent limits the application of rosin resin in the medical field.

[0004] For example, Chinese patent application 202111132863.0 discloses a method for preparing a degradable rosin resin, which comprises the following steps: melting the rosin under the protection of an inert gas; adding an unsaturated acid and reacting; adding a catalyst and a mixed alcohol and reacting; removing the water generated by the reaction, cooling, adding an antioxidant and a degradation accelerator, and mixing evenly to obtain the rosin resin. The rosin resin prepared by this invention is degradable and has a good appearance. When used in degradable hot melt adhesives, it has good stability and good viscosity, and has good application prospects. However, this application does not study the effect of rosin resin on cell activity, and the resulting degradable rosin resin cannot be better applied in the medical field.

[0005] For example, Chinese patent application No. 201810328598.5 discloses a method for preparing an ultra-light-colored rosin resin, the preparation steps of which include: first preparing a catalyst A for catalytic hydrogenation of rosin, then adding rosin and catalyst A to a reactor and sealing it, then vacuuming, leak checking, and exhausting the air, maintaining the reactor at normal pressure, then heating and melting the rosin, then introducing hydrogen to react, and then filtering and removing volatile components under negative pressure to obtain hydrogenated rosin; then reacting the hydrogenated rosin with glycerol to prepare rosin glycerol ester, and finally cooling, granulating, and packaging to obtain the ultra-light-colored rosin resin. This application still does not study the effect of rosin resin on cell activity, and the obtained ultra-light-colored rosin resin cannot be better applied in the medical field.

[0006] Therefore, it is necessary to develop a preparation method of rosin resin that has little effect on cell activity and can show excellent cell compatibility. Summary of the Invention

[0007] Based on the problems existing in the prior art, this application aims to provide a method for preparing rosin resin. The rosin resin prepared by this method has little effect on cell activity, can show excellent cell compatibility, and has important application value in the medical field.

[0008] To achieve the above-mentioned object of the invention, the present invention adopts the following technical solution: a method for preparing rosin resin, comprising the following steps:

[0009] (1) Put rosin into the reactor and heat it to 180-200°C under the protection of inert gas to melt it;

[0010] (2) adding 0.01-0.5% of the weight of rosin as a catalyst and 6-12% of the weight of rosin as a polyol, and reacting at 200° C.-290° C. for 6-15 hours;

[0011] (3) Vacuuming until the rosin resin reaches a specified acid value;

[0012] (4) Add 0.01-0.5% of the weight of rosin as antioxidant, stir evenly, and discharge the material to obtain rosin resin.

[0013] In some preferred embodiments, a post-treatment agent is further added in the above step (3), and the amount of the post-treatment agent added is 1-5% by weight of the rosin.

[0014] As some preferred embodiments, the rosin in the above step (1) is selected from one or more of wood rosin, gum rosin, hydrogenated rosin, disproportionated rosin, tall oil rosin and polymerized rosin;

[0015] Preferably, the rosin is horsetail rosin and / or wetland rosin.

[0016]

Term Explanation

[0017] Hydrogenated rosin: Hydrogenated rosin is formed by saturating some or all of the conjugated double bonds of abietic resin acids with hydrogen under the action of a catalyst, at specific temperatures and pressures. Rosin with some or all of the conjugated double bonds saturated with hydrogen is called hydrogenated rosin.

[0018] Disproportionated rosin: Disproportionated rosin is produced by a disproportionation reaction in which part of the rosin is oxidized and the other part is reduced in the presence of a catalyst. Disproportionated rosin is a mixture of dehydroabietic acid, dihydroabietic acid, and tetrahydroabietic acid.

[0019] Tall oil rosin: Tall oil rosin comes from the wood pulp and paper industry and is processed from black liquor recovered from kraft pulping.

[0020] Polymerized rosin: Polymerized rosin is a product obtained by bimolecular polymerization of the conjugated double bonds of abietic resin acids in rosin.

[0021] As some preferred embodiments, the catalyst described in the above step (2) is one or more selected from thiophenol compounds, hypophosphorous acid, hypophosphite, phosphorous acid, phosphite, alkali metal, alkaline earth metal and metal oxide.

[0022] As some preferred embodiments, the polyol described in the above step (2) is selected from one or more of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, glycerol, trimethylolpropane, 1,2,4-butanetriol, sorbitol, mannitol and pentaerythritol.

[0023] Preferably, the polyol is selected from one or more of glycerol, trimethylolpropane and pentaerythritol;

[0024] More preferably, the polyol is selected from glycerol and / or pentaerythritol.

[0025] More preferably, the polyol is a mixture of glycerol and pentaerythritol, with a mass ratio of 5-11:1-7; preferably 5:1.

[0026] As some preferred embodiments, the post-treatment agent is selected from one or more of compounds containing epoxy groups, isocyanates, and compounds that can react with carboxylate groups at relatively low temperatures to form macromolecules.

[0027] in,

[0028] The epoxy group-containing compound is selected from one or more of ethylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerol triglycidyl ether, glycidyl methacrylate, 4,4-dihydroxy-3,3,5,5-tetramethyldiphenylmethane diglycidyl ether and bisphenol A diglycidyl ether.

[0029] The isocyanate is selected from one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate.

[0030] As some preferred embodiments, the post-treatment agent is a mixture of ethylene glycol diglycidyl ether and toluene diisocyanate, with a mass ratio of 1-4:1-4; preferably 3:2.

[0031] As some preferred embodiments, the specified acid value in the above step (3) refers to a rosin resin acid value of less than 4; preferably, a rosin resin acid value of less than 2; and more preferably, a rosin resin acid value of less than 1.

[0032] As some preferred embodiments, the antioxidant described in the above step (4) is selected from one or more of 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, β-(4-hydroxyphenyl-3,5-di-tert-butyl)propionate and phosphite.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] (1) The present invention avoids the generation of monorosin acid ester during the esterification reaction by controlling the amount of polyol added.

[0035] (2) In the present application, a post-treatment agent is added to react the residual rosin acid and the low molecular weight free acid to generate substances with a larger molecular weight, and the prepared rosin resin has better weather resistance.

[0036] (3) The rosin resin prepared in this application has little effect on cell activity, shows excellent cell compatibility, and has important application value in the medical field. DETAILED DESCRIPTION

[0037] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further explained below in conjunction with specific embodiments. However, the following embodiments are only preferred embodiments of the present invention and are not exhaustive. Based on the embodiments in the embodiments, other embodiments obtained by those skilled in the art without making any creative work are all within the scope of protection of the present invention.

[0038] The experimental methods in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are commercially available unless otherwise specified.

[0039] Example 1 A method for preparing rosin resin

[0040] The following steps are involved:

[0041] (1) Place 600 g of horsetail rosin in a reaction flask equipped with a thermometer and a stirrer, and heat to 200°C under nitrogen protection to melt;

[0042] (2) adding 1.2 g of 4,4-thiobis(6-tert-butyl-3-methylphenol) and 72 g of glycerol, heating the mixture from 200°C to 270°C over 6 hours, and then stirring the mixture at 270°C for 8 hours;

[0043] (3) Vacuum for 1 hour to remove the water generated by the reaction, cool to 200°C, add 25 g of glycerol triglycidyl ether, and then stir and react at 200°C for 2 hours;

[0044] (4) Add 0.9 g of 2,6-di-tert-butyl-4-methylphenol, stir evenly, and discharge the material to obtain rosin resin.

[0045] Example 2 A method for preparing rosin resin

[0046] The following steps are involved:

[0047] (1) Place 600 g of horsetail rosin in a reaction flask equipped with a thermometer and a stirrer, and heat to 200°C under nitrogen protection to melt;

[0048] (2) adding 1.2 g of 4,4-thiobis(6-tert-butyl-3-methylphenol), 60 g of glycerol, and 12 g of pentaerythritol, heating the mixture from 200°C to 275°C over 6 hours, and then stirring the mixture at 275°C for 8 hours;

[0049] (3) Vacuum for 1 hour to remove the water generated by the reaction, cool to 200°C, add 15 g of ethylene glycol diglycidyl ether and 10 g of toluene diisocyanate, and then stir and react at 180°C for 2 hours;

[0050] (4) Add 0.9 g of 2,6-di-tert-butyl-4-methylphenol, stir evenly, and discharge the material to obtain rosin resin.

[0051] Example 3 A method for preparing rosin resin

[0052] The following steps are involved:

[0053] (1) Place 600 g of slash rosin in a reaction flask equipped with a thermometer and a stirrer, and heat to 200°C under nitrogen protection to melt;

[0054] (2) adding 1.2 g of 4,4-thiobis(6-tert-butyl-3-methylphenol) and 36 g of glycerol, heating the mixture from 200°C to 280°C over 6 hours, and then stirring the mixture at 280°C for 6 hours;

[0055] (3) Vacuum for 0.5 hours to remove the water generated by the reaction, cool to 220°C, add 30 g of bisphenol A diglycidyl ether, and then stir and react at 200°C for 2 hours;

[0056] (4) Add 0.9 g of 2,6-di-tert-butyl-4-methylphenol, stir evenly, and discharge the material to obtain rosin resin.

[0057] Example 4 A method for preparing rosin resin

[0058] The following steps are involved:

[0059] (1) Place 600 g of slash rosin in a reaction flask equipped with a thermometer and a stirrer, and heat to 200°C under nitrogen protection to melt;

[0060] (2) adding 0.6 g of nonylphenol disulfide oligomer and 72 g of pentaerythritol, heating the mixture from 200° C. to 290° C. over 6 hours, and then stirring the mixture at 290° C. for 8 hours;

[0061] (3) Vacuum for 1 hour to remove the water generated by the reaction, cool to 200°C, add 6 g of isophorone diisocyanate, and then stir and react at 180°C for 2 hours;

[0062] (4) Add 0.3 g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and stir evenly to obtain rosin resin.

[0063] Example 5 A method for preparing rosin resin

[0064] The following steps are involved:

[0065] (1) Place 600 g of horsetail rosin in a reaction flask equipped with a thermometer and a stirrer, and heat to 200°C under nitrogen protection to melt;

[0066] (2) adding 1.2 g of 4,4-thiobis(6-tert-butyl-3-methylphenol) and 66 g of glycerol, heating the mixture from 200°C to 270°C over 6 hours, and then stirring the mixture at 270°C for 8 hours;

[0067] (3) Vacuum for 3 hours to remove the water generated by the reaction, the residual resin acid and the small molecular free acid in the rosin resin until the acid value of the rosin resin is less than 4;

[0068] (4) Cool the mixture to 220°C, add 0.9 g of 2,6-di-tert-butyl-4-methylphenol, stir evenly, and discharge the mixture to obtain rosin resin.

[0069] Comparative Example 1: Preparation method of rosin resin

[0070] The following steps are involved:

[0071] (1) Place 600 g of horsetail rosin in a reaction flask equipped with a thermometer and a stirrer, and heat to 200°C under nitrogen protection to melt;

[0072] (2) adding 1.2 g of 4,4-thiobis(6-tert-butyl-3-methylphenol) and 72 g of glycerol, heating the mixture from 200°C to 270°C over 6 hours, and then stirring the mixture at 270°C for 8 hours;

[0073] (3) Vacuum for 1 hour to remove the water generated by the reaction;

[0074] (4) Cool the mixture to 220°C, add 0.9 g of 2,6-di-tert-butyl-4-methylphenol, stir evenly, and discharge the mixture to obtain rosin resin.

[0075] Comparative Example 2

[0076] The difference from Example 1 is that in step (2), 78 g of glycerol is added, and the rest are the same.

[0077] Comparative Example 3

[0078] Rosin resin prepared in Example 3 of Chinese patent application 202111132863.0.

[0079] Effect test example

[0080] 1. In vitro cytotoxicity test

[0081] Test item: In vitro cytotoxicity test (extract test)

[0082] Test method: ISO 10993-5:2009 Biological evaluation of medical devices Part 5: In vitro cytotoxicity test

[0083] Test substance: Sample preparation was performed according to ISO 10993-12:2012. The test substance was immersed in the extract at 37°C for 24 hours. The volume of the extract was calculated based on the surface area or mass of the test substance.

[0084] Cell line: L-929 cells (mouse fibroblasts)

[0085] Extraction medium: MEM + 10% FBS

[0086] Color development reagent: MTT

[0087] Negative control: medical disposable PE gloves

[0088] Positive control: medical latex gloves

[0089] Operating procedure: Extract test (MTT cytotoxicity test)

[0090] The prepared cell suspension was inoculated into a 96-well culture plate. Blank, negative, positive, and test sample groups were set up, with 100 μL of cell suspension in each well. The plates were incubated in a CO2 incubator (containing 5% CO2 by volume, the same below) at 37°C for 24 hours, after which the original culture medium was discarded. Fresh cell culture medium was added to the blank control group, the negative control extract was added to the negative control group, the positive control solution or the positive control extract was added to the positive control group, and the test samples were added to the test material extract, with 100 μL added to each well. The plates were incubated in a CO2 incubator for another 24 hours. Twenty-four hours after the culture medium was replaced, cell morphology was observed under a microscope. 50 μL of 1 mg / mL MTT solution was added to each well. The plates were incubated for another 2 hours, after which the liquid was discarded. 100 μL of isopropanol was added to the plates, and the plates were shaken on a shaker for 10 minutes. The absorbance was measured at 570 nm and 650 nm using a microplate reader to calculate the relative survival rate (RGR) and determine cytotoxicity.

[0091] Test results:

[0092] In vitro cytotoxicity test (extract test)

[0093] According to ISO 10993.5-2009, a cell viability of ≥70% is considered non-cytotoxic.

[0094] According to ISO 10993.5-2009, a cell viability <70% is considered cytotoxic.

[0095] The test results are shown in Table 1 below.

[0096] Table 1 Relative viability test of rosin resin cells prepared in Examples 1-5 and Comparative Examples 1-3

[0097]

[0098] The test data in Table 1 above show that the rosin resins prepared in Examples 1-5 of the present application have a relatively high relative cell survival rate, reaching approximately 80%. However, in Comparative Example 1, the preparation method was changed, i.e., the acid value of the rosin resin was not controlled during the vacuuming process, resulting in a significantly lower relative cell survival rate. Changing the amount of polyol added in Comparative Example 2 also significantly affected the relative cell survival rate. In Comparative Example 3, the addition of maleic anhydride resulted in a higher acid value of the resulting rosin resin, which also significantly affected the relative cell survival rate.

[0099] 2. Weather resistance test

[0100] The color changes of the rosin resins obtained in Examples 1-5 and Comparative Examples 1-3 after aging at 175° C. for 0 h, 4 h, and 8 h were respectively detected. The results are shown in Table 2 below:

[0101] Table 2 Weathering resistance test of rosin resin prepared in Examples 1-5 and Comparative Examples 1-3

[0102]

[0103] The test data in Table 2 show that the rosin resins prepared in Examples 1-5 of the present application exhibit weather resistance. After heat aging at 175°C for 8 hours, the color of the rosin resins increased by no more than two shades. However, the rosin resins prepared in Comparative Examples 1-3 all contained residual resin acid and small molecular free acid, resulting in poor weather resistance.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that although the technical solutions of the present invention may be modified or replaced by equivalents, this does not deviate from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a rosin resin, characterized in that: The specific steps are as follows: (1) Put rosin into the reactor and heat it to 180-200°C under the protection of inert gas to melt it; (2) adding 0.01-0.5% of the weight of rosin as a catalyst and 6-12% of the weight of rosin as a polyol, and reacting at 200° C.-290° C. for 6-15 hours; (3) Vacuuming until the rosin resin reaches a specified acid value; (4) adding an antioxidant at a concentration of 0.01-0.5% by weight of rosin, stirring evenly, and discharging the material to obtain rosin resin; The polyol described in step (2) is a mixture of glycerol and pentaerythritol, and the mass ratio of the two is 5-11:1-7; In step (3), a post-treatment agent is also required to be added, and the amount of the post-treatment agent added is 1-5% by weight of the rosin; the post-treatment agent is a mixture of ethylene glycol diglycidyl ether and toluene diisocyanate, and the mass ratio thereof is 1-4:1-4; The specified acid value described in step (3) means that the acid value of the rosin resin is less than 4.

2. The preparation method according to claim 1, wherein: The mass ratio of the glycerol to the pentaerythritol is 5:

1.

3. The preparation method according to claim 1, wherein: The mass ratio of ethylene glycol diglycidyl ether to toluene diisocyanate is 3:

2.

4. The preparation method according to claim 1, wherein: The specified acid value described in step (3) means that the acid value of the rosin resin is less than 2.

5. The preparation method according to claim 1, wherein: The specified acid value described in step (3) means that the acid value of the rosin resin is less than 1.

6. The preparation method according to claim 1, wherein: The antioxidant described in step (4) is one or more selected from 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, β-(4-hydroxyphenyl-3,5-di-tert-butyl) propionate and phosphite.

7. A rosin resin prepared according to the preparation method according to any one of claims 1 to 6.

8. Use of the rosin resin according to claim 7 in the preparation of medical adhesive tape.

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