Plant-based resin capable of contacting food as well as preparation method and application of plant-based resin

Abstract

The invention relates to the technical field of resin, in particular to plant-based resin capable of making contact with food and a preparation method and application thereof.The plant-based resin is prepared from, by weight, 40-50 parts of soybean oil, 12-18 parts of tung oil, 20-25 parts of pentaerythritol, 5-8 parts of diethylene glycol, 3-6 parts of trimethylolpropane, 15-20 parts of maleated rosin, 20-25 parts of polylactic resin and 18-22 parts of butyl acetate. 0.1 to 0.5 part of an antioxidant and 0.01 to 0.05 part of tetrabutyl titanate. According to the plant-based resin capable of making contact with the food, by selecting the raw materials and matching the resin framework with the flexible connecting material, the mechanical performance and adhesive force of the plant-based resin are improved, and the plant-based resin can be rapidly, firmly and permanently attached to a printing stock and can be applied to ink preparation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resin, in particular to a food-contactable plant-based resin and a preparation method and application thereof. BACKGROUND

[0002] The most core pain point of current food packaging is safety risk. Traditional petroleum-based ink usually contains mineral oil saturated hydrocarbon, mineral oil aromatic hydrocarbon, photoinitiator, plasticizer and other components. These substances are easy to migrate from the outer layer of the packaging to the food, posing a health risk, especially in high-fat foods. With the increasingly stringent global regulations and the media's reports on packaging safety incidents, consumers' concerns about food contamination by packaging are increasing.

[0003] Resin for ink is the heart and soul of ink, which determines most of the key performance of ink. The food safety of ink is first determined by resin. In order to improve safety, choosing plant-based resin can reduce pollution from the source. Plant-based resin uses natural and renewable plant resources as raw materials, and its chemical structure itself does not contain harmful substances of petroleum-based, greatly reducing the potential risk of toxic substance migration, providing consumers with a more secure choice.

[0004] However, the mechanical properties and durability of the existing plant-based resin are not good, and the adhesion is also not as good as traditional synthetic resin. Therefore, it is an urgent problem in the art to provide a more durable and stable plant-based resin. SUMMARY

[0005] The present application aims to at least overcome one of the defects of the prior art, and provides a food-contactable plant-based resin and a preparation method and application thereof. By selecting raw materials, the resin skeleton and flexible connecting material are matched to improve the mechanical properties and adhesion of the plant-based resin, which can be quickly, firmly and durably attached to the printing material, and can be applied in ink preparation.

[0006] In a first aspect, the embodiments of the present application provide a food-contactable plant-based resin, which is realized by the following technical solutions: A food-contactable plant-based resin, comprising the following preparation raw materials by weight: Soybean oil 40-50 parts, tung oil 12-18 parts, pentaerythritol 20-25 parts, diethylene glycol 5-8 parts, trimethylolpropane 3-6 parts, maleic rosin 15-20 parts, polylactic acid resin 20-25 parts, butyl acetate 18-22 parts, antioxidant 0.1-0.5 parts, and tetrabutyl titanate 0.01-0.05 parts.

[0007] The food-contactable plant-based resin according to the embodiments of the present application has at least the following beneficial effects: The molecular structure of the soybean oil of the present application contains long fatty acid chains and unsaturated double bonds, the long fatty acid chains provide flexibility and chain segment movement ability, and the unsaturated double bonds provide a chemical reaction active site. The soybean oil can reduce the brittleness of the resin, make the ink film after curing have better folding resistance and toughness, thereby obtaining good adhesion on food packaging, and at the same time improve the wettability of the pigment, so that the ink has bright color, good color development and good gloss.

[0008] The maleic rosin of the present application can enhance the hardness and heat resistance of the resin, solve the problem of too soft and sticky of pure vegetable oil resin, improve the scratch resistance and heat resistance of the ink film, and at the same time, the polar carboxyl functional group can form strong hydrogen bonds or chemical bonds with various substrates, improve the adhesion of the ink, and improve the compatibility of the resin with pigments and additives.

[0009] The polylactic acid resin of the present application has a relatively high molecular weight and a regular molecular structure, can form a continuous film with a certain strength, and makes up for the defects of poor film forming property and low strength when using soybean oil or rosin resin alone, and improves the strength and scratch resistance of the ink film.

[0010] The tung oil of the present application is mainly composed of triglyceride, and each fatty acid chain contains a conjugated triene, which has more active sites, so that the tung oil can undergo more chemical reactions, has a fast drying speed and can quickly form a tough coating film. The tung oil has strong adhesion, and the resin made of the tung oil can be firmly adhered to the surface of various materials to provide long-lasting protection effect. The tung oil has good weather resistance and corrosion resistance, and can improve the durability of the resin.

[0011] The food contactable plant-based resin of the present application improves the mechanical properties and adhesion of the plant-based resin by selecting raw materials and matching the resin skeleton with flexible connecting material, and can be quickly, firmly and durably adhered to the substrate, and can be applied in ink preparation.

[0012] According to some embodiments of the present application, the antioxidant is selected from at least one of 2,6-di-tert-butyl-p-cresol, tert-butyl hydroquinone, butylated hydroxyanisole, p-benzoquinone or o-methyl-p-benzoquinone. The antioxidant in the present application can increase the storage time of the food contactable plant-based resin, maintain the activity of the groups in the resin, and improve the curing effect of the ink.

[0013] According to some embodiments of the present application, the preparation method of the maleic rosin comprises the following steps: S1. Heat 50-60 parts of rosin to 180-190°C, then add 15-20 parts of maleic anhydride, and react at 180-190°C for a certain time; S2. Add glycidyl acrylate 12-16 parts, p-hydroxyanisole 0.05-0.1 parts, cetyl trimethyl ammonium bromide 0.2-0.5 parts, N,N-dimethylformamide 200-300 parts, and heat to 150-180℃ under nitrogen atmosphere for 6-9h. After the reaction is completed, filter out the impurities in the solution, wash, and vacuum dry to obtain maleic rosin.

[0014] Further, the reaction time in step S1 is 2-3h.

[0015] Further, the washing in step S2 is washing with n-hexane.

[0016] In a second aspect, the embodiments of the present application provide a preparation method of the plant-based resin that can contact food as described above, which is implemented through the following technical solution: A preparation method of a plant-based resin that can contact food, comprising the following steps: (1) Add soybean oil and tetrabutyl titanate according to weight parts and mix, add pentaerythritol, pass nitrogen, heat to 110℃, stir, continue to heat to 210-240℃ and maintain the temperature; (2) Cool to 160℃, add tung oil, diethylene glycol, trimethylolpropane, maleic rosin, and polylactic acid resin, stir, heat to 220-230℃ and maintain the temperature; (3) Cool to 160℃, add butyl acetate and antioxidant, mix uniformly and cool to room temperature to obtain the plant-based resin that can contact food.

[0017] According to some embodiments of the present application, the temperature maintaining time in step (1) is 2-4h.

[0018] According to some embodiments of the present application, the temperature maintaining time in step (2) is 3-5h.

[0019] The preparation method of the plant-based resin that can contact food according to the embodiments of the present application has at least the following beneficial effects: The preparation method of the present application has simple steps, does not require harsh production conditions and equipment, has no pollution in the manufacturing process, no toxic substance emission, does not harm the health of the operators, ensures the safety of production, has good economic benefits, and is suitable for industrialized production.

[0020] In a third aspect, the embodiments of the present application provide the application of the plant-based resin that can contact food as described above in ink. The ink made of the plant-based resin that can contact food of the present application has fast ink curing speed, high font gloss, strong font adhesion, and is not easy to fade. DETAILED DESCRIPTION

[0021] For the purposes of the present application, the technical solutions and advantages will be further described in detail below with reference to specific embodiments. The embodiments described herein are only a part of the embodiments of the present application and should not be understood as limiting the scope of protection of the present application. Example 1

[0022] Preparation of the plant-based resin that can contact food: (1) Soybean oil 45 parts, tetrabutyl titanate 0.03 parts were added and mixed according to weight parts, pentaerythritol 22 parts was added, nitrogen was introduced, the temperature was raised to 110°C, stirring, the temperature was continuously raised to 225°C and the temperature was maintained for 3h; (2) The temperature was lowered to 160°C, tung oil 15 parts, diethylene glycol 7 parts, trimethylolpropane 4 parts, maleic rosin 18 parts, polylactic acid resin 23 parts were added, stirring, the temperature was raised to 225°C and the temperature was maintained for 4h; (3) The temperature was lowered to 160°C, butyl acetate 20 parts, 2,6-di-tert-butyl-p-cresol 0.3 parts were added, mixed uniformly and lowered to room temperature to obtain the plant-based resin that can contact food; The preparation method of the maleic rosin is as follows: S1. The rosin 55 parts was heated to 185°C, then maleic anhydride 17 parts was added, and the reaction was carried out at 185°C for 2.5h; S2. Glycidyl acrylate 14 parts, p-hydroxyanisole 0.08 parts, cetyltrimethylammonium bromide 0.3 parts, N,N-dimethylformamide 260 parts were added, the temperature was raised to 160°C under nitrogen atmosphere and the reaction was carried out for 8h, after the reaction was completed, the impurities in the solution were removed by filtration, washed with n-hexane and vacuum dried to obtain the maleic rosin. Example 2

[0023] Preparation of the plant-based resin that can contact food: (1) Soybean oil 50 parts, tetrabutyl titanate 0.01 parts were added and mixed according to weight parts, pentaerythritol 25 parts was added, nitrogen was introduced, the temperature was raised to 110°C, stirring, the temperature was continuously raised to 210°C and the temperature was maintained for 4h; (2) The temperature was lowered to 160°C, tung oil 12 parts, diethylene glycol 8 parts, trimethylolpropane 3 parts, maleic rosin 20 parts, polylactic acid resin 20 parts were added, stirring, the temperature was raised to 230°C and the temperature was maintained for 3h; (3) The temperature was lowered to 160°C, butyl acetate 22 parts, tert-butyl hydroquinone 0.1 parts were added, mixed uniformly and lowered to room temperature to obtain the plant-based resin that can contact food; The preparation method of the maleic rosin is as follows: S1. The rosin 60 parts was heated to 180°C, then maleic anhydride 20 parts was added, and the reaction was carried out at 180°C for 3h; S2. Add glycidyl acrylate 12 parts, p-hydroxyanisole 0.1 part, cetyltrimethylammonium bromide 0.2 part, N,N-dimethylformamide 300 parts, and heat to 150°C under a nitrogen atmosphere for 9h. After the reaction is completed, filter out the impurities in the solution, wash with n-hexane, and vacuum dry to obtain maleic rosin. Example 3

[0024] Preparation of a food-contactable plant-based resin: (1) Add soybean oil 40 parts, tetrabutyl titanate 0.05 parts, and mix. Add pentaerythritol 20 parts, and stir while heating to 110°C. Continue to heat to 240°C and maintain the temperature for 2h. (2) Cool to 160°C, and add tung oil 18 parts, diethylene glycol 5 parts, trimethylolpropane 6 parts, maleic rosin 15 parts, and polylactic acid resin 25 parts. Stir, heat to 220°C, and maintain the temperature for 5h. (3) Cool to 160°C, and add butyl acetate 18 parts and butylated hydroxyanisole 0.5 parts. Mix well and cool to room temperature to obtain a food-contactable plant-based resin. The preparation method of the maleic rosin is as follows: S1. Heat rosin 50 parts to 190°C, and then add maleic anhydride 15 parts. React at 190°C for 2h. S2. Add glycidyl acrylate 16 parts, p-hydroxyanisole 0.05 parts, cetyltrimethylammonium bromide 0.5 parts, and N,N-dimethylformamide 200 parts. Heat to 180°C under a nitrogen atmosphere for 6h. After the reaction is completed, filter out the impurities in the solution, wash with n-hexane, and vacuum dry to obtain maleic rosin. Example 4

[0025] Preparation of a food-contactable plant-based resin: (1) Add soybean oil 45 parts and tetrabutyl titanate 0.02 parts, and mix. Add pentaerythritol 23 parts, and stir while heating to 110°C. Continue to heat to 220°C and maintain the temperature for 3h. (2) Cool to 160°C, and add tung oil 14 parts, diethylene glycol 6 parts, trimethylolpropane 5 parts, maleic rosin 17 parts, and polylactic acid resin 22 parts. Stir, heat to 230°C, and maintain the temperature for 4h. (3) Cool to 160°C, and add butyl acetate 21 parts and ortho-methyl hydroquinone 0.2 parts. Mix well and cool to room temperature to obtain a food-contactable plant-based resin. The preparation method of the maleic rosin is as follows: S1. Heat rosin 52 parts to 188°C, and then add maleic anhydride 18 parts. React at 188°C for 2h. S2. Add glycidyl acrylate 14 parts, p-hydroxyanisole 0.07 parts, cetyltrimethylammonium bromide 0.4 parts, N,N-dimethylformamide 250 parts, and heat to 160°C under a nitrogen atmosphere for 7h. After the reaction is completed, filter out the impurities in the solution, wash with n-hexane, and vacuum dry to obtain maleic rosin.

[0026] Comparative Example 1 Preparation of a food contactable plant-based resin: (1) Add soybean oil 45 parts, tetrabutyl titanate 0.03 parts, and mix. Add pentaerythritol 22 parts, introduce nitrogen, heat to 110°C, stir, continue to heat to 225°C, and maintain the temperature for 3h; (2) Cool to 160°C, add soybean oil 15 parts, diethylene glycol 7 parts, trimethylolpropane 4 parts, maleic rosin 18 parts, and polylactic acid resin 23 parts, stir, heat to 225°C, and maintain the temperature for 4h; (3) Cool to 160°C, add butyl acetate 20 parts, 2,6-di-tert-butyl-p-cresol 0.3 parts, mix uniformly, and cool to room temperature to obtain a food contactable plant-based resin; The preparation method of the maleic rosin is as follows: S1. Heat rosin 55 parts to 185°C, then add maleic anhydride 17 parts, and react at 185°C for 2.5h; S2. Add glycidyl acrylate 14 parts, p-hydroxyanisole 0.08 parts, cetyltrimethylammonium bromide 0.3 parts, N,N-dimethylformamide 260 parts, heat to 160°C under a nitrogen atmosphere for 8h, filter out the impurities in the solution after the reaction is completed, wash with n-hexane, and vacuum dry to obtain maleic rosin.

[0027] Comparative Example 2 Preparation of a food contactable plant-based resin: (1) Add soybean oil 45 parts, tetrabutyl titanate 0.03 parts, and mix. Add pentaerythritol 22 parts, introduce nitrogen, heat to 110°C, stir, continue to heat to 225°C, and maintain the temperature for 3h; (2) Cool to 160°C, add tung oil 15 parts, diethylene glycol 7 parts, trimethylolpropane 4 parts, maleic rosin 41 parts, stir, heat to 225°C, and maintain the temperature for 4h; (3) Cool to 160°C, add butyl acetate 20 parts, 2,6-di-tert-butyl-p-cresol 0.3 parts, mix uniformly, and cool to room temperature to obtain a food contactable plant-based resin; The preparation method of the maleic rosin is as follows: S1. Heat rosin 55 parts to 185°C, then add maleic anhydride 17 parts, and react at 185°C for 2.5h; S2. Add glycidyl acrylate 14 parts, p-hydroxyanisole 0.08 parts, cetyltrimethylammonium bromide 0.3 parts, N,N-dimethylformamide 260 parts, and heat to 160°C under a nitrogen atmosphere for 8h. After the reaction is completed, filter out the impurities in the solution, wash with n-hexane, and vacuum dry to obtain maleic rosin.

[0028] Comparative Example 3 Preparation of a food-contactable plant-based resin: (1) Add soybean oil 45 parts, tetrabutyl titanate 0.03 parts, and mix. Add pentaerythritol 22 parts, introduce nitrogen, heat to 110°C, stir, continue to heat to 225°C, and maintain the temperature for 3h; (2) Cool to 160°C, add tung oil 15 parts, diethylene glycol 7 parts, trimethylolpropane 4 parts, rosin 18 parts, and polylactic acid resin 23 parts, stir, heat to 225°C, and maintain the temperature for 4h; (3) Cool to 160°C, add butyl acetate 20 parts, and 2,6-di-tert-butyl-p-cresol 0.3 parts, mix evenly, and cool to room temperature to obtain a food-contactable plant-based resin.

[0029] Experimental Example Take the food-contactable plant-based resins prepared in Examples 1-4 and Comparative Examples 1-3, add wax paste, anti-emulsifier, and color powder respectively to prepare inks, and print the inks on food packaging paper by offset printing respectively. The related properties of the inks and the printed matter are tested, and the test methods are as follows: The color is tested according to the standard of GB / T 13217.1-2020 (requirement ≥ level 4).

[0030] The tack is tested according to the standard of GB / T 18723-2002 (requirement 7.0-16.0).

[0031] The adhesion is tested according to the standard of GB / T 13217.1-2009 (requirement ≥ 95%).

[0032] The test method for wear resistance is a left-right swing type abrasion tester, and the test conditions are 4 pounds / 50 back and forth. The test evaluation standard for wear resistance is from poor to excellent, and is divided into levels 1-5.

[0033] The performance test data is shown in Table 1 below: Table 1

[0034] As can be seen from Table 1, the food-contactable plant-based resins of Examples 1-4 have good performance. Under the matching of specific raw material ratios, the color, tack, adhesion, and wear resistance of the prepared inks can all reach a high level.

[0035] The preparation raw materials of Comparative Example 1 are replaced with equal amount of soybean oil instead of tung oil, and the rest are the same as Example 1. The color, adhesion, and wear resistance of the ink made of the plant-based resin for contact food prepared in Comparative Example 1 are all significantly deteriorated, which shows that the tung oil of the present application is mainly composed of triglyceride, and contains one conjugated triene in each fatty acid chain, and the more active sites enable the tung oil to undergo more chemical reactions, and the fast drying speed can quickly form a tough coating film. The tung oil has strong adhesion, and the resin made of the tung oil can be firmly adhered to the surface of various materials to provide a long-lasting protection effect. The tung oil has good weather resistance and corrosion resistance, and can improve the durability of the resin.

[0036] The preparation raw materials of Comparative Example 2 are replaced with equal amount of maleic rosin instead of polylactic acid resin, and the rest are the same as Example 1. The wear resistance of the ink made of the plant-based resin for contact food prepared in Comparative Example 2 is significantly deteriorated, which shows that the polylactic acid resin of the present application has a high molecular weight and a regular molecular structure, and can form a continuous film with a certain strength, which makes up for the defects of poor film-forming property and low strength of pure soybean oil or rosin resin, and improves the strength and scratch resistance of the ink film.

[0037] The preparation raw materials of Comparative Example 3 are replaced with equal amount of rosin instead of maleic rosin, and the rest are the same as Example 1. The color, viscosity, adhesion, and wear resistance of the ink made of the plant-based resin for contact food prepared in Comparative Example 3 are all significantly deteriorated, which shows that the maleic rosin of the present application can enhance the hardness and heat resistance of the resin, solve the problem of too soft and sticky of pure plant oil resin, and improve the scratch resistance and heat resistance of the ink film. At the same time, the polar carboxyl functional group of the maleic rosin can form strong hydrogen bonds or chemical bonds with various printing substrates, improve the adhesion of the ink, and improve the compatibility of the resin with pigments and additives.

[0038] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements, or variations can be made to these embodiments without departing from the principles and purposes of the present application, and the technical solutions after these changes, modifications, replacements, or variations will all fall within the protection scope of the present application.

Claims

1. A plant-based resin that can contact food, characterized by, The preparation raw materials include the following weight parts: Soybean oil 40-50 parts, tung oil 12-18 parts, pentaerythritol 20-25 parts, diethylene glycol 5-8 parts, trimethylolpropane 3-6 parts, maleic rosin 15-20 parts, polylactic acid resin 20-25 parts, butyl acetate 18-22 parts, antioxidant 0.1-0.5 parts, tetrabutyl titanate 0.01-0.05 parts.

2. The plant-based resin that can come into contact with food according to claim 1, characterized by, The antioxidant is selected from at least one of 2,6-di-tert-butyl-p-cresol, tert-butyl hydroquinone, butylated hydroxyanisole, p-benzoquinone or o-methyl-p-benzoquinone.

3. The plant-based resin that can contact food according to claim 1, wherein, The preparation method of the maleic rosin includes the following steps: S1. Heating rosin 50-60 parts to 180-190℃, then adding maleic anhydride 15-20 parts, reacting at 180-190℃ for a certain time; S2. Adding glycidyl acrylate 12-16 parts, p-hydroxyanisole 0.05-0.1 parts, cetyltrimethylammonium bromide 0.2-0.5 parts, N,N-dimethylformamide 200-300 parts, heating to 150-180℃ under nitrogen atmosphere for 6-9h, after the reaction is completed, filtering out the impurities in the solution, washing, vacuum drying to obtain maleic rosin.

4. The plant-based resin that can contact food according to claim 3, characterized by, The reaction time in step S1 is 2-3h.

5. The plant-based resin that can contact food according to claim 3, characterized by, The washing in step S2 uses n-hexane for washing.

6. A method of producing a plant-based resin that can come into contact with food as claimed in any one of claims 1 to 5, characterized by, The method includes the following steps: (1) Adding soybean oil, tetrabutyl titanate and mixing according to weight parts, adding pentaerythritol, passing nitrogen, heating to 110℃, stirring, continuing to heat to 210-240℃ and keeping the temperature; (2) Cooling to 160℃, adding tung oil, diethylene glycol, trimethylolpropane, maleic rosin, polylactic acid resin, stirring, heating to 220-230℃ and keeping the temperature; (3) Cooling to 160℃, adding butyl acetate, antioxidant, mixing uniformly and cooling to room temperature to obtain a food contactable plant-based resin.

7. A method of preparing a plant-based resin that can come into contact with food according to claim 6, characterized in that, The temperature keeping time in step (1) is 2-4h.

8. The method of claim 6, wherein the plant-based resin is prepared by contacting food. The temperature keeping time in step (2) is 3-5h.

9. Application of the food contactable plant-based resin according to any one of claims 1 to 5 in ink.

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