Bio-based polymer emulsifier as well as preparation method and application thereof

Abstract

The invention relates to the technical field of polymer synthesis, in particular to a bio-based polymer emulsifier and a preparation method and application thereof.The preparation method comprises the steps that S1, castor oil and sulfydryl-containing acid react under ultraviolet irradiation in the presence of a photoinitiator, and after the reaction is completed, castor oil-based polycarboxylic acid is obtained through washing and distillation; s2, reacting the castor oil-based polycarboxylic acid prepared in the step S1 with glycerin monostearate and diisocyanate under the action of a catalyst to obtain a bio-based polymer emulsifier; after the bio-based polymer emulsifier provided by the invention is blended with polyvinyl alcohol, the water resistance and mechanical property of polyurethane and the high adhesive property of polyvinyl alcohol can be integrated, various properties of a traditional polyvinyl alcohol adhesive are effectively improved, for example, the problems of insufficient storage stability and insufficient waterproof property of the traditional polyvinyl alcohol adhesive are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer synthesis, and in particular to a bio-based polymer emulsifier and a preparation method and application thereof. Background Art

[0002] In the related art, the adhesives widely used in the wood industry are formaldehyde-based adhesives, such as the widely used urea-formaldehyde resin, phenol-formaldehyde resin, and melamine-formaldehyde resin; formaldehyde-based adhesives have excellent bonding properties and water resistance, but there are disadvantages that cannot be ignored: 1) The raw materials for the production of formaldehyde-based adhesives need to be obtained from petrochemical products, and their production process requires the consumption of non-renewable fossil resources; 2) Formaldehyde-based adhesives release formaldehyde during production and use, which can cause great harm to the environment and human body. Therefore, the wood adhesive industry needs to develop an environmentally friendly adhesive. Polyvinyl alcohol adhesives have high bonding strength to wood, fast curing speed, simple manufacturing process, wide source, low cost and no "trialdehyde", which is an environmentally friendly adhesive and is very popular in the market. However, the polyvinyl alcohol adhesives currently on the market have disadvantages such as insufficient stability, easy mold, and insufficient water resistance, and cannot be used in special environments such as humidity. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of existing polyvinyl alcohol adhesives such as insufficient stability and insufficient water resistance, and to provide a bio-based polymer emulsifier and its preparation method and application. The bio-based polymer emulsifier provided by the present invention is blended with a polyvinyl alcohol-starch solution to prepare an adhesive. The adhesive can effectively overcome the defects of traditional polyvinyl alcohol adhesives during storage and use.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for preparing a bio-based polymer emulsifier, comprising the following steps:

[0006] S1, reacting castor oil with an acid containing a thiol group in the presence of a photoinitiator under ultraviolet light, and washing and distilling the reaction to obtain a castor oil-based polycarboxylic acid;

[0007] S2. The castor oil-based polycarboxylic acid prepared in step S1 is reacted with glyceryl monostearate and diisocyanate in the presence of a catalyst to obtain a bio-based polymer emulsifier.

[0008] Preferably, in step S1, the acid containing a mercapto group is 3-mercaptopropionic acid.

[0009] Preferably, in step S1, the photoinitiator is photoinitiator-1173.

[0010] Preferably, in step S1, the irradiation conditions of ultraviolet light include: wavelength of 350-380nm, radiation intensity of 1500-1800μW·cm -2 , the irradiation time is 2-3h.

[0011] Preferably, in step S1, the weight ratio of the castor oil to the thiol-containing acid is 1:(0.12-0.16).

[0012] Preferably, in step S2, the amounts of the raw material components are: 10-15 parts by weight of castor oil-based polycarboxylic acid, 20-30 parts by weight of glyceryl monostearate, 18-30 parts by weight of diisocyanate, and 0.5-1 part by weight of catalyst.

[0013] Preferably, the diisocyanate is selected from one of MDI, HDI and IPDI.

[0014] The present invention also provides a bio-based polymer emulsifier, which is prepared by the above-mentioned preparation method.

[0015] The present invention also provides a use of the bio-based polymer emulsifier prepared by the above preparation method in emulsifying polyvinyl alcohol.

[0016] Preferably, the application includes:

[0017] Prepare a polyvinyl alcohol-starch solution, then add the bio-based polymer emulsifier into the polyvinyl alcohol-starch solution, and use it as an adhesive after it is evenly dispersed.

[0018] Preferably, the weight ratio of the bio-based polymer emulsifier to the polyvinyl alcohol-starch solution is (6-10): (80-100);

[0019] Preferably, the preparation method of the polyvinyl alcohol-starch solution comprises: dispersing 10-15 parts by weight of polyvinyl alcohol and 1-3 parts by weight of triethanolamine in 60-80 parts by weight of deionized water, then adding 5-10 parts by weight of oxidized corn starch while heating, heating to 80-90° C. after the addition is complete, and stirring at this temperature until the solution is completely dissolved, thereby obtaining the polyvinyl alcohol-starch solution.

[0020] Compared with the prior art, the present invention has the following technical effects:

[0021] According to the preparation method provided by the present invention, the double bonds contained in the castor oil can react with an acid containing a mercapto group in the presence of a photoinitiator and under ultraviolet light to obtain a castor oil-based polycarboxylic acid, which is used as a hydrophilic chain extender to react with glyceryl monostearate and diisocyanate under the action of a catalyst to obtain a castor oil-based polyurethane prepolymer with strong emulsification and dispersibility. The bio-based polymer emulsifier provided by the present invention is used as an emulsifier and curing agent for polyvinyl alcohol. The bio-based polymer emulsifier can be uniformly dispersed in the hydrophilic polyvinyl alcohol to form a stable composite structure. The hydrophobic segments in the bio-based polymer emulsifier can reduce the water absorption of the film, while the polyurethane cross-linked network can block water penetration. The introduction of the polyurethane system can improve the tensile strength and toughness of the polyvinyl alcohol adhesive, compensating for the brittleness of the pure polyvinyl alcohol film. Therefore, the bio-based polymer emulsifier provided by the present invention, after being blended with polyvinyl alcohol, can combine the water resistance and mechanical properties of polyurethane with the high adhesion performance of polyvinyl alcohol, effectively improving various aspects of the performance of traditional polyvinyl alcohol adhesives, such as improving their insufficient storage stability and insufficient waterproof performance. DETAILED DESCRIPTION

[0022] 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 with reference to specific embodiments.

[0023] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0024] Unless otherwise specified, the experimental materials and reagents used in the following examples can be obtained from commercial sources. If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions.

[0025] As mentioned above, the present invention provides a method for preparing a bio-based polymer emulsifier, comprising the following steps:

[0026] S1, reacting castor oil with an acid containing a thiol group in the presence of a photoinitiator under ultraviolet light, and washing and distilling the reaction to obtain a castor oil-based polycarboxylic acid;

[0027] S2. The castor oil-based polycarboxylic acid prepared in step S1 is reacted with glyceryl monostearate and diisocyanate in the presence of a catalyst to obtain a bio-based polymer emulsifier.

[0028] In the present invention, the castor oil is a renewable vegetable oil. The double bonds contained in the castor oil can react with an acid containing a mercapto group in the presence of a photoinitiator and under ultraviolet light to obtain a castor oil-based polycarboxylic acid. The castor oil-based polycarboxylic acid is used as a hydrophilic chain extender and reacted with glyceryl monostearate and diisocyanate under the action of a catalyst to obtain a castor oil-based polyurethane prepolymer with strong emulsification and dispersibility.

[0029] The bio-based polymer emulsifier provided by the present invention is used as an emulsifier and curing agent for polyvinyl alcohol. The bio-based polymer emulsifier can be uniformly dispersed in the hydrophilic polyvinyl alcohol to form a stable composite structure. The hydrophobic segments in the bio-based polymer emulsifier can reduce the water absorption of the film, while the polyurethane cross-linked network can block water penetration. The introduction of the polyurethane system can improve the tensile strength and toughness of the polyvinyl alcohol adhesive, compensating for the brittleness of the pure polyvinyl alcohol film. Therefore, the bio-based polymer emulsifier provided by the present invention, after being blended with polyvinyl alcohol, can combine the water resistance and mechanical properties of polyurethane with the high adhesion performance of polyvinyl alcohol, effectively improving various aspects of the performance of traditional polyvinyl alcohol adhesives, such as improving their insufficient storage stability and insufficient waterproof performance.

[0030] In the present invention, the thiol-containing acid can be selected from a wide range. In order to ensure the emulsifying properties of the final bio-based polymer emulsifier, in step S1, the thiol-containing acid is 3-mercaptopropionic acid. The inventors of the present application found that by adopting 3-mercaptopropionic acid, the reaction rate is ensured, and the reaction yield is higher than the reaction yield of other thiol-containing acids.

[0031] In the present invention, the type of the photoinitiator can be selected from a wide range. In order to ensure the emulsification performance of the final bio-based polymer emulsifier, in step S1, the photoinitiator is photoinitiator-1173.

[0032] In the present invention, the irradiation conditions of the ultraviolet light can be selected within a wide range. In order to ensure the emulsification performance of the final bio-based polymer emulsifier, in step S1, the irradiation conditions of the ultraviolet light include: a wavelength of 350-380nm, a radiation intensity of 1500-1800μW·cm -2 , the irradiation time is 2-3h.

[0033] In the present invention, the amount of the castor oil and the thiol-containing acid can be selected within a wide range. In order to ensure the emulsification performance of the final bio-based polymer emulsifier, the weight ratio of the castor oil to the thiol-containing acid is 1:(0.12-0.16).

[0034] In step S2 of the present invention, the amount of each raw material component can be selected within a wide range. In order to ensure the emulsification performance of the final bio-based polymer emulsifier, in step S2, the amount of each raw material component is: 10-15 parts by weight of castor oil-based polycarboxylic acid, 20-30 parts by weight of glyceryl monostearate, 18-30 parts by weight of diisocyanate, and 0.5-1 part by weight of catalyst.

[0035] In the present invention, the diisocyanate can be selected from those well known to those skilled in the art, for example, one of MDI (diphenylmethane diisocyanate), HDI (hexamethylene diisocyanate) and IPDI (isophorone diisocyanate).

[0036] The present invention also provides a bio-based polymer emulsifier prepared by the above preparation method; and the present invention also provides the use of the bio-based polymer emulsifier prepared by the above preparation method in emulsifying polyvinyl alcohol.

[0037] In some embodiments of the present invention, the application includes: preparing a polyvinyl alcohol-starch solution, and then adding the bio-based polymer emulsifier to the polyvinyl alcohol-starch solution, and then using it as an adhesive after it is evenly dispersed.

[0038] The weight ratio of the bio-based polymer emulsifier to the polyvinyl alcohol-starch solution can be selected within a wide range. In some embodiments of the present invention, the weight ratio of the bio-based polymer emulsifier to the polyvinyl alcohol-starch solution is (6-10): (80-100).

[0039] In this invention, oxidized corn starch and polyurethane introduced during the emulsification process inhibit microbial growth, overcoming the mold-forming defect of traditional polyvinyl alcohol adhesives. The oxidized corn starch and polyurethane hydrophobic segments dually inhibit microbial growth, extending the adhesive's service life.

[0040] In the present invention, the preparation method of the polyvinyl alcohol-starch solution comprises: dispersing 10-15 parts by weight of polyvinyl alcohol and 1-3 parts by weight of triethanolamine in 60-80 parts by weight of deionized water, then adding 5-10 parts by weight of oxidized corn starch while heating, heating to 80-90° C. after the addition is complete, and stirring at this temperature until the polyvinyl alcohol-starch solution is completely dissolved, thereby obtaining the polyvinyl alcohol-starch solution.

[0041] The following is a specific description of the method of emulsifying polyvinyl alcohol with a bio-based polymer emulsifier provided by the present invention to form a composite adhesive through specific examples.

[0042] Example 1

[0043] This embodiment provides a preparation method and application of a bio-based polymer emulsifier:

[0044] S1. 100 parts by weight of castor oil (refined castor oil, molecular weight 930, average functionality 2.7) and 14 parts by weight of 3-mercaptopropionic acid are reacted in the presence of 1.1 parts by weight of photoinitiator-1173 under ultraviolet light. After the reaction is completed, the mixture is washed with water four times and distilled to obtain a light yellow viscous liquid, which is a castor oil-based polycarboxylic acid;

[0045] The UV irradiation conditions are: wavelength 365nm, radiation intensity 1700μW·cm -2 , the irradiation time is 2h.

[0046] S2. In a three-necked flask, castor oil-based polycarboxylic acid is added as a hydrophilic chain extender, followed by the addition of glyceryl monostearate, the temperature is raised to 90°C, dehydrated, and then MDI and dilauryl alcohol as a catalyst are added to react to obtain a bio-based polymer emulsifier;

[0047] The amounts of the raw material components are as follows: 10 parts by weight of castor oil-based polycarboxylic acid, 22 parts by weight of glyceryl monostearate, 21 parts by weight of IPDI, and 0.5 parts by weight of dilauryl glycol as a catalyst.

[0048] S3. Prepare a polyvinyl alcohol-starch solution by dispersing 12 parts by weight of polyvinyl alcohol and 1.5 parts by weight of triethanolamine in 75 parts by weight of deionized water, then add 7 parts by weight of oxidized corn starch while heating the mixture. After the addition is complete, heat the mixture to 80° C. and stir while maintaining the temperature until the mixture is completely dissolved, thereby obtaining a polyvinyl alcohol-starch solution.

[0049] Add 6 parts by weight of the bio-based polymer emulsifier prepared in step S2 to 90 parts by weight of the polyvinyl alcohol-starch solution at one time, and after being evenly dispersed, it can be used as an adhesive;

[0050] The adhesive was sprayed onto the surface of the artificial board for 1 hour, and then completely dried for 48 hours before testing the tensile strength and water absorption rate. The test results are summarized in Table 1.

[0051] Example 2

[0052] This embodiment provides a preparation method and application of a bio-based polymer emulsifier:

[0053] S1, 95 parts by weight of castor oil (refined castor oil, molecular weight 930, average functionality 2.7) and 13.3 parts by weight of 3-mercaptopropionic acid are reacted in the presence of 1.0 part by weight of photoinitiator-1173 under ultraviolet light. After the reaction is completed, the mixture is washed with water four times and distilled to obtain a light yellow viscous liquid, which is castor oil-based polycarboxylic acid;

[0054] The UV irradiation conditions are: wavelength 365nm, radiation intensity 1700μW·cm -2 , the irradiation time is 2h.

[0055] S2. In a three-necked flask, castor oil-based polycarboxylic acid is added as a hydrophilic chain extender, followed by glyceryl monostearate. The temperature is raised to 90°C for dehydration, followed by addition of HMDI and catalyst dilauryl to react to obtain a bio-based polymer emulsifier.

[0056] The amounts of the raw material components are as follows: 12 parts by weight of castor oil-based polycarboxylic acid, 28 parts by weight of glyceryl monostearate, 28 parts by weight of IPDI, and 0.5 parts by weight of dilauryl glycol as a catalyst.

[0057] S3. Prepare a polyvinyl alcohol-starch solution by dispersing 15 parts by weight of polyvinyl alcohol and 2 parts by weight of triethanolamine in 70 parts by weight of deionized water, then add 8 parts by weight of oxidized corn starch while heating the mixture. After the addition is complete, heat the mixture to 80° C. and stir while maintaining the temperature until the mixture is completely dissolved, thereby obtaining a polyvinyl alcohol-starch solution.

[0058] Add 6 parts by weight of the bio-based polymer emulsifier prepared in step S2 to 95 parts by weight of the polyvinyl alcohol-starch solution at one time, and after it is evenly dispersed, it can be used as an adhesive;

[0059] The adhesive was sprayed onto the surface of the artificial board for 1 hour, and then completely dried for 48 hours before testing the tensile strength and water absorption rate. The test results are summarized in Table 1.

[0060] Example 3

[0061] This embodiment provides a preparation method and application of a bio-based polymer emulsifier:

[0062] S1, 90 parts by weight of castor oil (refined castor oil, molecular weight 930, average functionality 2.7) and 12.6 parts by weight of 3-mercaptopropionic acid are reacted in the presence of 1.0 part by weight of photoinitiator-1173 under ultraviolet light. After the reaction is completed, the mixture is washed with water four times and distilled to obtain a light yellow viscous liquid, which is castor oil-based polycarboxylic acid;

[0063] The UV irradiation conditions are: wavelength 365nm, radiation intensity 1700μW·cm -2 , the irradiation time is 2h.

[0064] S2. In a three-necked flask, castor oil-based polycarboxylic acid is added as a hydrophilic chain extender, followed by glyceryl monostearate. The temperature is raised to 90°C for dehydration, followed by the addition of IPDI and catalyst dilauryl to react to obtain a bio-based polymer emulsifier.

[0065] The amounts of the raw material components are as follows: 15 parts by weight of castor oil-based polycarboxylic acid, 30 parts by weight of glyceryl monostearate, 28 parts by weight of IPDI, and 0.5 parts by weight of dilauryl glycol as a catalyst.

[0066] S3. Prepare a polyvinyl alcohol-starch solution by dispersing 10 parts by weight of polyvinyl alcohol and 3 parts by weight of triethanolamine in 77 parts by weight of deionized water, then adding 5 parts by weight of oxidized corn starch while heating. After the addition is complete, heat to 80° C. and stir while maintaining the temperature until the starch is completely dissolved, thereby obtaining a polyvinyl alcohol-starch solution.

[0067] Add 6 parts by weight of the bio-based polymer emulsifier prepared in step S2 to 85 parts by weight of the polyvinyl alcohol-starch solution at one time, and after it is evenly dispersed, it can be used as an adhesive;

[0068] The adhesive was sprayed onto the surface of the artificial board for 1 hour, and then completely dried for 48 hours before testing the tensile strength and water absorption rate. The test results are summarized in Table 1.

[0069] Comparative Example 1

[0070] The preparation method and application of the bio-based polymer emulsifier provided in this comparative example are basically the same as those in Example 1, except that, in this comparative example, the acid containing a thiol group is selected as thioglycolic acid; the other conditions remain unchanged, and the obtained adhesive is sprayed on the surface of the artificial board for 1 hour, and then the tensile strength and water absorption rate are tested after it is completely dried for 48 hours; the test results are summarized in Table 1.

[0071] Table 1:

[0072]

[0073]

[0074] In Table 1, commercially available polyvinyl alcohol emulsion was purchased from Anhui Wanwei High-tech Materials Co., Ltd., with the trade name PVA17-88. As can be seen from the data in Table 1, the adhesive formed by blending the bio-based polymer emulsifier provided by the present invention with polyvinyl alcohol has good strength performance and a low water absorption expansion rate, effectively overcoming the defects of traditional polyvinyl alcohol adhesives in strength and water absorption performance.

[0075] Comparative Example 3

[0076] In this comparative example, steps S1 and S2 are the same as those in Example 1, and oxidized corn starch is not added in step S3. Specifically, 12 parts by weight of polyvinyl alcohol and 1.5 parts by weight of triethanolamine are dispersed in 75 parts by weight of deionized water, and then the temperature is raised to 80° C. and stirred until completely dissolved to obtain a polyvinyl alcohol solution. 6 parts by weight of the bio-based polymer emulsifier prepared in step S2 are added to 90 parts by weight of the polyvinyl alcohol solution at one time, and after being evenly dispersed, the solution can be used as an adhesive.

[0077] The adhesive was sprayed onto the surface of the artificial board for 1 hour, and then completely dried for 48 hours before testing the tensile strength and water absorption rate. The test results are summarized in Table 1.

[0078] Antibacterial testing:

[0079] The artificial boards of Example 1 and Comparative Example 3 were subjected to antibacterial test with reference to Appendix A "Test Method for Antibacterial Performance" of JC / T2039-2010 "Antibacterial and Mildew-Resistant Wood Decorative Panels". Staphylococcus aureus (CGMCC: 1.282) was used as the target bacterial species. The test results are shown in Table 2.

[0080] Table 2:

[0081] Sample Antibacterial rate (%) Example 1 95.6％ Commercially available polyvinyl alcohol emulsion 75.8％ Comparative Example 3 72.2％

[0082] In Table 2, commercially available polyvinyl alcohol emulsion was purchased from Anhui Wanwei High-tech Materials Co., Ltd., with the trade name PVA17-88. It can be seen from the data in Table 2 that the application of the bio-based polymer emulsifier provided by the present invention has the advantage of good antibacterial effect, can effectively inhibit the growth of microorganisms during actual use, and achieve the advantage of extending the service life of the adhesive.

[0083] The basic principles, main features, and characteristics of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a bio-based polymer emulsifier, characterized in that: The following steps are involved: S1, reacting castor oil with an acid containing a thiol group in the presence of a photoinitiator under ultraviolet light, and washing and distilling the reaction to obtain a castor oil-based polycarboxylic acid; S2. The castor oil-based polycarboxylic acid prepared in step S1 is reacted with glyceryl monostearate and diisocyanate in the presence of a catalyst to obtain a bio-based polymer emulsifier.

2. The preparation method according to claim 1, characterized in that In step S1, the acid containing a mercapto group is 3-mercaptopropionic acid.

3. The preparation method according to claim 1, characterized in that In step S1, the photoinitiator is photoinitiator-1173.

4. The preparation method according to claim 1, characterized in that In step S1, the irradiation conditions of ultraviolet light include: wavelength of 350-380nm, radiation intensity of 1500-1800μW·cm -2 , the irradiation time is 2-3h.

5. The preparation method according to claim 1, characterized in that In step S1, the weight ratio of the castor oil to the thiol-containing acid is 1:(0.12-0.16).

6. The preparation method according to claim 1, characterized in that In step S2, the amounts of the raw material components are: 10-15 parts by weight of castor oil-based polycarboxylic acid, 20-30 parts by weight of glyceryl monostearate, 18-30 parts by weight of diisocyanate, and 0.5-1 part by weight of catalyst.

7. The preparation method according to claim 1, characterized in that The diisocyanate is selected from one of MDI, HDI and IPDI.

8. A bio-based polymer emulsifier, characterized in that: The method is prepared according to any one of claims 1 to 7.

9. Use of the bio-based polymer emulsifier prepared by the preparation method according to any one of claims 1 to 7 in emulsifying polyvinyl alcohol.

10. The use according to claim 9, characterized in that The applications include: Prepare a polyvinyl alcohol-starch solution, then add the bio-based polymer emulsifier into the polyvinyl alcohol-starch solution, and use it as an adhesive after it is evenly dispersed; Preferably, the weight ratio of the bio-based polymer emulsifier to the polyvinyl alcohol-starch solution is (6-10): (80-100); Preferably, the preparation method of the polyvinyl alcohol-starch solution comprises: dispersing 10-15 parts by weight of polyvinyl alcohol and 1-3 parts by weight of triethanolamine in 60-80 parts by weight of deionized water, then adding 5-10 parts by weight of oxidized corn starch while heating, heating to 80-90° C. after the addition is complete, and stirring at this temperature until the solution is completely dissolved, thereby obtaining the polyvinyl alcohol-starch solution.

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