A vegetable oil polyol and its preparation method and application

Abstract

The present invention belongs to the field of organic synthesis technology and specifically relates to a vegetable oil polyol, a preparation method, and applications thereof. The present invention uses vegetable oil acid and trimethylolpropane as raw materials to produce a vegetable oil polyol through esterification, epoxidation, and ring-opening reactions. The vegetable oil polyol has physical and chemical properties similar to castor oil but is cheaper than castor oil. The polyurethane material produced using the vegetable oil polyol as raw material exhibits excellent tensile properties and aging resistance, is low-cost, and uses renewable raw materials, meeting the requirements of green chemistry and sustainable development. Its tensile properties and aging resistance are superior to those of castor oil-based polyurethane materials, expanding the application scenarios of polyurethane and providing excellent social and economic benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and in particular relates to a vegetable oil polyol and a preparation method and application thereof. Background Art

[0002] Polyurethane, a polymer material, is widely used in fields such as construction, furniture, and automobiles. The raw material for polyurethane, oligomer polyols, is mostly derived from non-renewable fossil resources. Finding renewable alternatives to traditional raw materials has become a pressing requirement for the development of polyurethane material technology. The main alternative to oligomer polyols is vegetable oil polyols, which are currently mostly derived from castor oil, soybean oil, rapeseed oil, or palm oil. These polyols contain active functional groups such as double bonds and ester groups, and can be synthesized into bio-based polyols through chemical modification.

[0003] Castor oil is a plant-based polyol widely used in the preparation of polyurethanes. It can be used directly as a polyol in reactions, or its derivative polyols can be obtained through alcoholysis and transesterification. Polyether polyols can also be synthesized through ring-opening polymerization of propylene oxide / ethylene oxide at the hydroxyl group using a bimetallic catalyst. Polyurethane materials prepared from castor oil and its derivative polyols generally exhibit good thermal stability, hydrolysis resistance, and chemical resistance, and can be used to prepare polyurethane foams, elastomers, adhesives, and coatings. However, castor oil production is low, resulting in high prices. Furthermore, castor oil's simple structure makes modifications to it even more expensive. Furthermore, polyurethanes prepared from castor oil exhibit poor tensile properties and aging resistance. Therefore, obtaining a low-cost plant-based polyol that produces polyurethanes with excellent tensile and aging resistance remains a pressing issue in the field. Summary of the Invention

[0004] The object of the present invention is to provide a vegetable oil polyol and a preparation method and application thereof. The vegetable oil polyol provided by the present invention has low cost and the prepared polyurethane material has excellent tensile properties and aging resistance.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing vegetable oil polyols, comprising the following steps:

[0007] (1) Oleic acid and trimethylolpropane are mixed and subjected to esterification reaction to obtain trimethylolpropane oleate, the structure of which is shown in Formula I:

[0008]

[0009] (2) The trimethylolpropane oleate, the acid solution and the hydrogen peroxide solution are mixed to carry out an epoxidation reaction to obtain epoxy trimethylolpropane oleate, the structure of which is shown in Formula II:

[0010]

[0011] (3) The epoxy oleic acid trimethylolpropane ester and sulfuric acid solution are mixed to perform a ring-opening reaction to obtain a vegetable oil polyol having a structure as shown in Formula III:

[0012]

[0013] Preferably, in step (1), the mass ratio of oleic acid to trimethylolpropane is 700-900:210-270;

[0014] In step (2), the mass ratio of trimethylolpropane oleate to the acid solution is 1000:12-20;

[0015] The mass concentration of the acid solution is 80-100%;

[0016] The mass ratio of trimethylolpropane oleate and hydrogen peroxide solution is 1000:120-200;

[0017] The mass concentration of the hydrogen peroxide solution is 30-70%;

[0018] In step (3), the mass ratio of trimethylolpropane epoxyoleate to concentrated sulfuric acid in the sulfuric acid solution is 1000:1-1.8;

[0019] The mass concentration of the sulfuric acid solution is 0.5-1.5%.

[0020] Preferably, the esterification reaction is a multi-stage reaction, the temperature distribution of the multi-stage reaction is 160-230° C.; the total insulation time of the esterification reaction is 8-16 hours; and the esterification reaction is carried out in a protective gas.

[0021] Preferably, the temperature of the epoxidation reaction is 60-80° C., and the insulation time is 4-10 hours.

[0022] Preferably, the temperature of the ring-opening reaction is 95-107° C., and the insulation time is 4-8 hours.

[0023] Preferably, the temperature of the esterification reaction is obtained by programmed temperature rise, wherein oleic acid and trimethylolpropane are mixed and heated and kept warm in sequence for a first heating reaction, a second heating reaction, a third heating reaction, and a fourth heating reaction.

[0024] Preferably, the temperature of the first heating reaction is 160-170°C, and the holding time is 1-2 hours;

[0025] The temperature of the second heating reaction is 180-190°C, and the holding time is 1-2 hours;

[0026] The temperature of the third heating reaction is 200-210°C, and the insulation time is 1-2 hours;

[0027] The temperature of the fourth heating reaction is 220-230° C., and the insulation time is 5-10 hours.

[0028] The present invention also provides a vegetable oil polyol obtained by the preparation method described in the above scheme, the structure of which is shown in Formula III.

[0029] The present invention also provides the use of the vegetable oil polyol described in the above scheme in synthesizing polyurethane.

[0030] Preferably, the use of the vegetable oil polyol in the synthesis of polyurethane comprises the following steps:

[0031] (1) mixing a vegetable oil polyol, a plasticizer, an inorganic filler, a defoamer, and a catalyst, and removing water to obtain a premix;

[0032] (2) mixing the premix and the isocyanate group-containing compound to carry out a curing reaction to obtain polyurethane.

[0033] The present invention provides a method for preparing a vegetable oil polyol. Using vegetable oil acid and trimethylolpropane as raw materials, the method produces a vegetable oil polyol through esterification, epoxidation, and ring-opening reactions. The polyol has physical and chemical properties similar to castor oil but is cheaper than castor oil. The polyurethane material produced using the vegetable oil polyol as raw material exhibits superior tensile properties and aging resistance to castor oil-based polyurethane materials, demonstrating broad market prospects.

[0034] The present invention also provides a vegetable oil polyol obtained by the preparation method described in the above scheme. The vegetable oil polyol provided by the present invention has low cost, renewable raw materials, meets the requirements of green chemistry and sustainable development, and can be used to synthesize polyurethane materials.

[0035] The present invention also provides the use of the vegetable oil polyol described in the above scheme in the synthesis of polyurethane. The vegetable oil polyol provided by the present invention produces a polyurethane material with superior tensile properties and aging resistance compared to castor oil-based polyurethane materials, expanding the application scenarios of polyurethane and providing excellent social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 This is a hydrogen nuclear magnetic resonance spectrum of trimethylolpropane oleate prepared in Example 1 of the present invention;

[0038] Figure 2 This is a hydrogen nuclear magnetic resonance spectrum of trimethylolpropane epoxy oleate prepared in Example 1 of the present invention;

[0039] Figure 3 This is a hydrogen nuclear magnetic resonance spectrum of the vegetable oil polyol prepared in Example 1 of the present invention;

[0040] Figure 4 This is an infrared spectrum of trimethylolpropane oleate prepared in Example 1 of the present invention;

[0041] Figure 5 This is an infrared spectrum of trimethylolpropane epoxy oleate prepared in Example 1 of the present invention;

[0042] Figure 6 This is an infrared spectrum of the vegetable oil polyol prepared in Example 1 of the present invention;

[0043] Figure 7 This is a curing temperature-time curve diagram of the polyurethane prepared in Application Example 1 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0044] The present invention provides a method for preparing vegetable oil polyols, comprising the following steps:

[0045] (1) Oleic acid and trimethylolpropane are mixed and subjected to esterification reaction to obtain trimethylolpropane oleate, the structure of which is shown in Formula I:

[0046]

[0047] (2) The trimethylolpropane oleate, the acid solution and the hydrogen peroxide solution are mixed to carry out an epoxidation reaction to obtain epoxy trimethylolpropane oleate, the structure of which is shown in Formula II:

[0048]

[0049] (3) The epoxy oleic acid trimethylolpropane ester and sulfuric acid solution are mixed to carry out a ring-opening reaction to obtain a vegetable oil polyol having a structure as shown in Formula III:

[0050]

[0051] The present invention mixes oleic acid and trimethylolpropane to carry out an esterification reaction to obtain trimethylolpropane oleate, the structure of which is shown in Formula I. In the present invention, the reaction equation of the esterification reaction is:

[0052]

[0053] In the present invention, the oleic acid and trimethylolpropane are preferably mixed by stirring; the stirring speed is preferably 200 to 300 rpm, more preferably 230 to 270 rpm.

[0054] In the present invention, the mass ratio of oleic acid to trimethylolpropane is preferably 700-900:210-270, more preferably 750-850:230-260, and further preferably 780-820:240-250.

[0055] In the present invention, the acid value of the reaction product of the esterification reaction is measured by sampling once per hour. Preferably, the reaction is terminated when the acid value of the sample is less than 0.5 mgKOH / g to obtain trimethylolpropane oleate as a yellow oil.

[0056] In the present invention, the esterification reaction is a multi-stage reaction, and the temperature of the multi-stage reaction is preferably distributed in the range of 160 to 230° C.; the total insulation time of the esterification reaction is preferably 8 to 16 hours; the esterification reaction is preferably carried out in a protective gas; the protective gas is preferably nitrogen; the esterification reaction is preferably carried out under stirring conditions; the stirring speed is preferably 200 to 300 rpm, more preferably 230 to 270 rpm.

[0057] In the present invention, the temperature of the esterification reaction is preferably obtained by programmed temperature increase, and the programmed temperature increase is preferably: oleic acid and trimethylolpropane are mixed and heated and kept warm in sequence for a first heating reaction, a second heating reaction, a third heating reaction, and a fourth heating reaction.

[0058] In the present invention, the temperature of the first heating reaction is preferably 160-170°C, more preferably 163-167°C, and the insulation time is preferably 1-2h; the temperature of the second heating reaction is preferably 180-190°C, more preferably 183-187°C, and the insulation time is preferably 1-2h; the temperature of the third heating reaction is preferably 200-210°C, more preferably 203-207°C, and the insulation time is preferably 1-2h; the temperature of the fourth heating reaction is preferably 220-230°C, more preferably 223-227°C, and the insulation time is preferably 5-10h, more preferably 6-8h.

[0059] In the present invention, the esterification reaction apparatus is preferably a reaction apparatus equipped with a stirring device, a thermometer, a water separator, and a reflux condenser; the reaction apparatus is preferably a reaction kettle or a three-necked round-bottom flask. The trimethylolpropane oleate obtained by the esterification reaction of the present invention has an acid value of ≤1.0 mgKOH / g, an iodine value of 95-105 I2 / 100g, and a hydroxyl value of 110-120 mgKOH / g.

[0060] After obtaining trimethylolpropane oleate, the present invention mixes the trimethylolpropane oleate, an acid solution, and a hydrogen peroxide solution to perform an epoxidation reaction to obtain epoxy trimethylolpropane oleate, the structural formula of which is shown in Formula II. In the present invention, the reaction equation of the epoxidation reaction is:

[0061]

[0062] In the present invention, the mixing of trimethylolpropane oleate, acid solution and hydrogen peroxide solution is preferably carried out by premixing trimethylolpropane oleate and acid solution at room temperature, then heating the system to 40-50° C., and mixing the obtained premix with hydrogen peroxide solution.

[0063] In the present invention, the system is heated to 40-50° C., preferably 43-47° C.; the premix and the hydrogen peroxide solution are preferably mixed by dropwise adding the hydrogen peroxide solution to the premix; the dropwise addition rate is preferably 4-6 g / min, more preferably 4.5-5.5 g / min.

[0064] In the present invention, the mass ratio of trimethylolpropane oleate to the acid solution is preferably 1000:12-20, more preferably 1000:13-18, and further preferably 1000:14-17; the mass concentration of the acid solution is preferably 80-100%, more preferably 85-95%; and the acid in the acid solution is preferably one or both of formic acid and acetic acid.

[0065] In the present invention, the mass ratio of trimethylolpropane oleate to hydrogen peroxide solution is preferably 1000:120-200, more preferably 1000:130-180, and further preferably 1000:145-160; the mass concentration of the hydrogen peroxide solution is preferably 30-70%, more preferably 50%.

[0066] In the present invention, the epoxidation reaction temperature is preferably 60-80°C, more preferably 65-75°C, and even more preferably 70°C, and the holding time is preferably 4-10 hours, more preferably 6-8 hours, and even more preferably 7 hours.

[0067] In the present invention, after the epoxidation reaction, the product is preferably separated and the resulting supernatant is sequentially washed with water, dehydrated, and filtered. The supernatant is preferably washed with water until neutral. The dehydration is preferably performed by vacuum distillation. The vacuum degree of the vacuum distillation is preferably -0.08 to -0.10 MPa, more preferably -0.09 MPa, and the temperature is preferably 100 to 110°C, more preferably 105°C. The target moisture content of the dehydration is preferably no greater than 0.2%. Filtration is used to remove mechanical impurities that may have been introduced during the experiment.

[0068] In the present invention, the epoxidation reaction apparatus is preferably a reaction apparatus equipped with a stirring device, a thermometer, a separatory funnel, and a reflux condenser; the reaction apparatus is preferably a four-necked round-bottom flask or a reactor. The present invention prepares trimethylolpropane epoxyoleate through the epoxidation reaction. The trimethylolpropane epoxyoleate is a yellow oil having an acid value of ≤2 mgKOH / g, an epoxy value of 1.3% to 1.6%, an iodine value of 70 to 80 I2 / 100g, and a hydroxyl value of 110 to 120 mgKOH / g.

[0069] After obtaining epoxy oleic acid trimethylolpropane ester, the present invention mixes the epoxy oleic acid trimethylolpropane ester with a sulfuric acid solution to carry out a ring-opening reaction to obtain a vegetable oil polyol having a structure shown in Formula III.

[0070] In the present invention, the reaction equation of the ring-opening reaction is:

[0071]

[0072] In the present invention, the mass ratio of the epoxy oleate trimethylolpropane ester to the concentrated sulfuric acid in the sulfuric acid solution is preferably 1000:1-1.8, more preferably 1000:1.2-1.6, and further preferably 1000:1.4; the preparation of the sulfuric acid solution preferably comprises the following steps: mixing 98% by mass concentrated sulfuric acid and distilled water to obtain a sulfuric acid solution; the mass concentration of the sulfuric acid solution is preferably 0.5-1.5%, more preferably 0.7-1.2%.

[0073] In the present invention, the temperature of the ring-opening reaction is preferably 95-107° C., more preferably 98-105° C., further preferably 100-103° C., and the holding time is preferably 4-8 h, more preferably 6 h.

[0074] In the present invention, the ring-opening reaction device is preferably a reaction device with a stirring device, a thermometer and a reflux condenser; the reaction device is preferably a three-necked round-bottom flask or a reactor.

[0075] In the present invention, after the ring-opening reaction is completed, the resulting reaction product is preferably cooled and dehydrated; the final temperature of the cooling is preferably 65-75°C, more preferably 70°C; the dehydration preferably comprises: vacuum distilling the cooled product followed by nitrogen evacuation; the vacuum degree of the evacuation is preferably -0.08-0.10 MPa, more preferably -0.09 MPa; the evacuation time is preferably 1-3 hours, more preferably 2 hours. The present invention removes residual water and acidic compounds by vacuum distillation, and when the vacuum distillation is completed until there are no bubbles, the vacuum distillation is continued with nitrogen evacuation.

[0076] The present invention also provides a vegetable oil polyol obtained by the preparation method described in the above scheme, the structure of which is shown in Formula III:

[0077]

[0078] The vegetable oil polyol provided by the present invention has an acid value of ≤0.7 mgKOH / g, a hydroxyl value of 155-175 mgKOH / g, an iodine value of 65-75 I2 / 100g, and a viscosity at 25°C of 600-800 cps.

[0079] The present invention also provides the use of the vegetable oil polyol described in the above scheme in synthesizing polyurethane.

[0080] In the present invention, the application of the vegetable oil polyol in the synthesis of polyurethane preferably comprises the following steps:

[0081] (1) removing water from the vegetable oil polyol to obtain a pretreated product;

[0082] (2) mixing the pretreated material and a compound containing an isocyanate group to carry out a curing reaction to obtain a polyurethane.

[0083] The present invention removes water from a vegetable oil polyol to obtain a pretreated product. In the present invention, the vegetable oil polyol is preferably mixed with one or more of a plasticizer, an inorganic filler, a defoamer, and a catalyst before the water is removed. The plasticizer is preferably dioctyl terephthalate; the inorganic filler is preferably calcium carbonate; the defoamer is preferably a silicone defoamer; the catalyst is preferably an organotin catalyst; and the organotin catalyst is preferably dibutyltin dilaurate.

[0084] In the present invention, the mass ratio of the vegetable oil polyol to the plasticizer is preferably 100:20-100, more preferably 100:50-100; the mass ratio of the vegetable oil polyol to the inorganic filler is preferably 100:50-200, more preferably 100:100-200; the mass ratio of the vegetable oil polyol to the defoaming agent is preferably 100:0.1-0.4, more preferably 100:0.15-0.30; the mass ratio of the vegetable oil polyol to the catalyst is preferably 100:0.05-0.10, more preferably 100:0.06-0.08.

[0085] In the present invention, the water removal method is preferably reduced pressure distillation; the vacuum degree of the reduced pressure distillation is preferably -0.08 to -0.10 MPa, more preferably -0.09 MPa, the temperature is preferably 100 to 110°C, more preferably 105°C, and the insulation time is preferably 1 to 3 hours, more preferably 2 hours.

[0086] After obtaining the pretreated material, the present invention mixes the pretreated material with an isocyanate group-containing compound to perform a curing reaction to obtain a polyurethane. In the present invention, the isocyanate group-containing compound preferably includes one or more of polymethylene polyphenyl polyisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate; the mass ratio of the pretreated material to the isocyanate group-containing compound is preferably 100:35-45, more preferably 100:38-42.

[0087] In the present invention, the temperature of the curing reaction is preferably room temperature, and the curing time is preferably 3 to 5 hours, more preferably 3.5 to 4.5 hours.

[0088] In order to further illustrate the present invention, the scheme of the present invention is described in detail below with reference to the accompanying drawings and embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0089] Example 1

[0090] A method for preparing vegetable oil polyols comprises the following steps:

[0091] (1) Esterification reaction:

[0092] In a three-necked round-bottom flask equipped with a stirring device, a thermometer, a water separator and a reflux condenser, 800 g of oleic acid and 240 g of trimethylolpropane were added in sequence, nitrogen was introduced and the temperature was raised to 170° C., 190° C. and 210° C. at 200 rpm with stirring, and the reaction was carried out by keeping the temperature at 230° C. for 4 hours. After that, sampling was started to measure the acid value, and sampling was carried out once every hour. When the acid value of the sample was less than 0.5 mgKOH / g, the reaction was terminated to obtain trimethylolpropane oleate as a yellow oil; the acid value, iodine value, iodine value and hydroxyl value were 0.45 mgKOH / g, 102.43 I2 / 100 g and 119.58 mgKOH / g, and the hydrogen nuclear magnetic resonance spectrum was as shown in FIG. Figure 1 As shown, the infrared spectrum is as follows Figure 4 As shown;

[0093] (2) Epoxidation reaction:

[0094] 1000 g of trimethylolpropane oleate described in step (1) and 15 g of formic acid with a mass fraction of 85% are added to a four-necked round-bottom flask with a stirring device, a thermometer, a separating funnel and a reflux condenser, and the temperature is raised to 40° C., and 125 g of hydrogen peroxide with a mass fraction of 70% is added dropwise at a rate of 4.5 g / min while stirring at a speed of 300 rpm. After the addition is complete, the mixture is kept warm at 70° C. for 8 h, the lower layer of acid water is separated, the upper layer of oily ester is washed with water until neutral, and water is removed by reduced pressure distillation at 100° C. and -0.1 MPa, and the mixture is filtered to obtain a light yellow oily substance, trimethylolpropane epoxy oleate; after testing, the acid value, epoxy value, iodine value, iodine value, and hydroxyl value of the substance are 1.32 mgKOH / g, 1.51%, 74.10I2 / 100g, and 115.13 mgKOH / g, and the hydrogen nuclear magnetic resonance spectrum thereof is as follows: Figure 2 As shown, the infrared spectrum is as follows Figure 5 As shown;

[0095] (3) Ring-opening reaction:

[0096] 1.5 g of 98% concentrated sulfuric acid was added to 120 g of distilled water and stirred to obtain a sulfuric acid solution. Then, 1000 g of the epoxy oleic acid trimethylolpropane ester prepared in step (2) and the sulfuric acid solution were sequentially added to a three-necked round-bottom flask equipped with a stirring device, a thermometer and a reflux condenser. The mixture was heated to 95° C. and refluxed for 8 h. After cooling to 70° C., the residual water and acidic compounds were removed by distillation under reduced pressure. When there were no bubbles, nitrogen was passed through and vacuum dehydration was continued for 2 h to obtain a vegetable oil polyol. After testing, the acid value, hydroxyl value, iodine value and viscosity at 25° C. were 0.28 mgKOH / g, 165.20 mgKOH / g, iodine value, 70.42 I2 / 100 g, and 654 cps, respectively. The hydrogen nuclear magnetic resonance spectrum was as shown in FIG. Figure 3 As shown, the infrared spectrum is as Figure 6 shown.

[0097] Figure 1 The H NMR spectrum of trimethylolpropane oleate prepared in Example 1 of the present invention is as follows: Figure 1 It can be found that the peak at δ = 0.88 ~ 0.89 ppm represents the methyl group, the peak at δ = 1.25 ~ 1.30 ppm represents the internal methylene group on the backbone chain of the oleic acid segment, the peak at δ = 1.62 ppm represents the methylene group connected to the methyl group in the oleic acid chain, the peak at δ = 2.02 ~ 2.04 ppm represents the methylene group at one end of the olefinic bond in the oleic acid chain, the peak at δ = 2.33 ~ 2.35 ppm represents the methylene group connected to the carbonyl group in the oleic acid chain, the peak at δ = 2.77 ppm represents the methylene group between the two olefinic bonds, and the peak at δ = 3.40 ~ 3.73 ppm represents the triolefinic bond. The methylene group connected to the methyl group in the hydroxymethylpropane group, the peak at δ = 4.01 to 4.03 ppm represents the methylene group -CH*2OCO- connected to the carbonyl group in the trimethylolpropane group, the peak at δ = 4.20 ppm represents the unreacted hydroxyl hydrogen -OH* in trimethylolpropane, and the peak at δ = 5.34 to 5.37 ppm represents the carbon-carbon double bond -CH*=CH*- on the oleic acid chain; it can be seen that the hydroxyl group in trimethylolpropane and the carboxyl group in oleic acid undergo esterification reaction to synthesize trimethylolpropane oleate, and at the same time, there is still a part of excess hydroxyl group in trimethylolpropane that has not reacted.

[0098] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of trimethylolpropane epoxy oleate prepared in Example 1 of the present invention. Figure 2 comparison Figure 1 It can be seen that Figure 2 A signal representing the chemical shift of methine hydrogen of the epoxy group appeared at δ=2.93 ppm, indicating that an epoxidation reaction occurred.

[0099] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the vegetable oil polyol prepared in Example 1 of the present invention. Figure 3 comparison Figure 2 It can be seen that in Figure 3 The signal representing the chemical shift of the methine hydrogen of the epoxy group at δ = 2.93 ppm disappeared, indicating that the epoxy group had been ring-opened.

[0100] Figure 4 The infrared spectrum of trimethylolpropane oleate prepared in Example 1 of the present invention is shown in FIG. Figure 4 It can be found that 3460cm -1 Attributable to the -OH stretching vibration absorption peak, 1061 cm -1 The stretching vibration absorption peaks are attributed to C-OH (primary alcohol), both of which indicate that some excess hydroxyl groups in trimethylolpropane are unreacted; 3008 cm -1The CH stretching vibration absorption peak at 2926 cm-1 is attributed to the unsaturated hydrocarbon CH=CH. -1 The absorption peak of CH asymmetric stretching vibration of -CH3 and -CH2- is 2854 cm -1 The absorption peak of CH symmetric stretching vibration of -CH3 and -CH2- is 1742 cm -1 The C=O stretching vibration absorption peak at 1243 cm-1 is attributed to the ester carbonyl group. -1 The absorption peak at 1173 cm is attributed to the asymmetric stretching vibration of the ester single bond COC. -1 The absorption peak is attributed to the symmetrical stretching vibration of the ester single bond COC, indicating that there are more ester bonds in the intermediate product, that is, the hydroxyl group in trimethylolpropane and the carboxyl group in oleic acid undergo esterification to synthesize trimethylolpropane oleate; 1463 cm -1 The peak of CH asymmetric bending vibration of -CH3 and -CH2- is 1384 cm -1 The absorption peak of CH symmetric bending vibration of -CH3 and -CH2- is 1354 cm -1 The absorption peak at 779 cm is attributed to the carbon-carbon single bond skeleton vibration of the four methylene carbons connected to the 2-position carbon in the trimethylolpropane group. -1 The absorption peak of CH bending vibration of unsaturated hydrocarbon CH=CH is 723 cm -1 The absorption peak is attributed to the plane rocking vibration of methylene.

[0101] Figure 5 The infrared spectrum of trimethylolpropane epoxy oleate prepared in Example 1 of the present invention is shown in FIG. Figure 5 comparison Figure 4 It can be seen that 3008cm -1 The CH stretching vibration absorption peak attributed to the unsaturated hydrocarbon CH=CH is significantly weakened, indicating that some carbon-carbon double bonds have undergone epoxidation reaction; however, due to the low degree of epoxidation, 840 cm is not marked in the infrared spectrum. -1 The asymmetric stretching vibration absorption peak of the nearby three-membered cyclic ether (epoxy bond)

[0102] Figure 6 This is the infrared spectrum of the vegetable oil polyol prepared in Example 1 of the present invention. Figure 6 comparison Figure 5 It can be seen that Figure 6 The peak positions of the characteristic peaks in Figure 5 There is no significant difference, which is due to Figure 5 No epoxy bond absorption peak was observed. Figure 6 After the ring opening, the disappearance of the epoxy bond is not observed; and after the ring opening, more hydroxyl groups are generated, so Figure 6 There is no significant change in the peak positions of the characteristic peaks. Figures 1 to 6 The detailed analysis fully demonstrates that the target vegetable oil polyols are successfully synthesized in the present invention.

[0103] Example 2

[0104] A method for preparing vegetable oil polyols comprises the following steps:

[0105] (1) Esterification reaction:

[0106] In a three-necked round-bottom flask equipped with a stirring device, a thermometer, a water trap and a reflux condenser, 700 g of oleic acid and 210 g of trimethylolpropane were added in sequence, nitrogen was introduced, and the temperature was raised to 160° C., 180° C., and 200° C. with stirring at 250 rpm, and the reaction was carried out by insulation for 2 h. After insulation for 6 h at 220° C., sampling was started to measure the acid value. Sampling was carried out once every hour. When the acid value of the sample was less than 0.5 mgKOH / g, the reaction was terminated to obtain trimethylolpropane oleate as a yellow oil; the acid value, iodine value, and hydroxyl value of the sample were 0.52 mgKOH / g, 98.13 I2 / 100g, and 115.47 mgKOH / g, respectively.

[0107] (2) Epoxidation reaction:

[0108] 1000 g of trimethylolpropane oleate described in step (1) and 18 g of 95% acetic acid by mass were added to a four-necked round-bottom flask equipped with a stirring device, a thermometer, a separating funnel and a reflux condenser, and the mixture was stirred and heated to 45° C. 180 g of 50% hydrogen peroxide by mass was added dropwise at a rate of 5 g / min while stirring at a speed of 250 rpm. After the addition was complete, the mixture was kept warm at 60° C. for 10 h, the lower layer of acid water was separated, the upper layer of oily ester was washed with water until neutral, and water was removed by reduced pressure distillation at 110° C. and −0.08 MPa, and the mixture was filtered to obtain a light yellow oily substance, trimethylolpropane epoxy oleate; the acid value, epoxy value, iodine value, and hydroxyl value of the substance were 1.51 mgKOH / g, 1.42%, 72.15I2 / 100g, and 113.22 mgKOH / g, respectively;

[0109] (3) Ring-opening reaction:

[0110] 1.3 g of 98% concentrated sulfuric acid was added to 100 g of distilled water and stirred uniformly to obtain a sulfuric acid solution. Then, 1000 g of the epoxy oleic acid trimethylolpropane ester prepared in step (2) and the sulfuric acid solution were sequentially added to a three-necked round-bottom flask equipped with a stirring device, a thermometer, and a reflux condenser. The mixture was heated to 100° C. with stirring and refluxed for 7 h. After cooling to 65° C., the mixture was distilled under reduced pressure to remove residual water and acidic compounds. When no bubbles were found, nitrogen was introduced and vacuum dehydration was continued for 3 h to obtain a vegetable oil polyol. The acid value, hydroxyl value, iodine value, and viscosity at 25° C. were 0.51 mgKOH / g, 160.32 mgKOH / g, and 69.33 I2 / 100 g, respectively, to obtain a vegetable oil polyol.

[0111] Example 3

[0112] A method for preparing vegetable oil polyols comprises the following steps:

[0113] (1) Esterification reaction:

[0114] In a three-necked round-bottom flask equipped with a stirring device, a thermometer, a water trap and a reflux condenser, 900 g of oleic acid and 270 g of trimethylolpropane were added in sequence, nitrogen was introduced, and the temperature was raised to 165° C., 185° C., and 205° C. with stirring at 300 rpm, and the reaction was kept at this temperature for 2 h. After the reaction was kept at 225° C. for 5 h, sampling was started to measure the acid value. Sampling was performed once every hour. When the acid value of the sample was less than 0.5 mgKOH / g, the reaction was terminated to obtain trimethylolpropane oleate as a yellow oil; the acid value, iodine value, and hydroxyl value of the sample were 0.61 mgKOH / g, 100.62 I2 / 100g, and 112.17 mgKOH / g, respectively.

[0115] (2) Epoxidation reaction:

[0116] 1000 g of the trimethylolpropane oleate described in step (1) and 20 g of formic acid with a mass fraction of 85% were added to a four-necked round-bottom flask equipped with a stirring device, a thermometer, a separating funnel and a reflux condenser, and the temperature was raised to 50° C. with stirring at a speed of 220 rpm, and 200 g of hydrogen peroxide with a mass fraction of 30% was added dropwise at a rate of 6 g / min. After the addition was complete, the mixture was kept warm at 80° C. for 4 h, the lower layer of acid water was separated, the upper layer of oily ester was washed with water until neutral, and water was removed by reduced pressure distillation at 110° C. and −0.08 MPa, and the mixture was filtered to obtain a light yellow oily substance, trimethylolpropane epoxy oleate; the acid value, epoxy value, iodine value, and hydroxyl value of the substance were 1.24 mgKOH / g, 1.57%, 76.23 I2 / 100 g, and 117.31 mgKOH / g, respectively.

[0117] (3) Ring-opening reaction:

[0118] 1.8 g of 98% concentrated sulfuric acid was added to 200 g of distilled water and stirred uniformly to obtain a sulfuric acid solution. Then, 1000 g of trimethylolpropane epoxy oleate prepared in step (2) and the sulfuric acid solution were sequentially added to a three-necked round-bottom flask equipped with a stirring device, a thermometer, and a reflux condenser. The mixture was heated to 103° C. with stirring and refluxed for 6 h. After cooling to 75° C., the mixture was distilled under reduced pressure to remove residual moisture and acidic compounds. When no bubbles were found, nitrogen was introduced and vacuum dehydration was continued for 2 h to obtain a vegetable oil polyol. The acid value, hydroxyl value, iodine value, and viscosity at 25° C. were 0.47 mgKOH / g, 172.36 mgKOH / g, 72.10 I2 / 100 g, and 765 cps, respectively.

[0119] Application Example 1

[0120] Formula: Example 1 vegetable oil polyol, R (the ratio of the amount of -NCO groups to the amount of -OH groups) = 1.1, 0.1% of the total weight of the defoamer, Example 1 vegetable oil polyol: PM-200 = 100:40.5 (mass ratio), room temperature during testing 16±1°C;

[0121] (1) Mix the vegetable oil polyol and the defoamer in proportion, stir evenly, heat to 110° C. and remove water by vacuum distillation to ensure that the water content is less than 0.05%. After the water content is qualified, cool to room temperature for use to obtain a premix;

[0122] (2) The premix and PM-200 were mixed evenly in proportion and cured at room temperature to obtain a polyurethane adhesive. The temperature and time were recorded during the curing process. The results were as follows: Figure 7 shown.

[0123] Comparative Application Example 1

[0124] Formula: Example 1 vegetable oil polyol, R = 1.1, 0.1% defoamer by weight, castor oil: PM-200 = 100:40 (mass ratio), room temperature during testing 16 ± 1 ° C;

[0125] (1) Castor oil and defoamer are mixed in proportion, stirred evenly, heated to 110° C. and distilled under reduced pressure to remove water, ensuring that the water content is less than 0.05%. After the water content is qualified, the mixture is cooled to room temperature for use to obtain a premix;

[0126] (2) The premix and PM-200 were mixed evenly in proportion and cured at room temperature to obtain a polyurethane adhesive. The temperature and time were recorded during the curing process. The results were as follows: Figure 7 shown.

[0127] according to Figure 7It can be seen that during the curing process, the vegetable oil polyol of Example 1 reached its maximum temperature of 32.5° C. at 35 min, and the castor oil also reached its maximum temperature of 32.9° C. at 35 min. The reaction rates and heat release degrees of the two were similar.

[0128] Application Example 2

[0129] Component A: 50g of the vegetable oil polyol from Example 1, 50g of dioctyl terephthalate, 100g of calcium carbonate, 0.1% of the total weight of the polyurethane defoamer, and 0.04g of an organotin catalyst;

[0130] Component B: PM-200 20g;

[0131] (1) Mix the raw materials of component A in proportion, stir evenly, heat to 110°C and remove water by vacuum distillation to ensure that the moisture content is less than 0.05%. After the moisture content is qualified, cool to room temperature for use to obtain a premix;

[0132] (2) The premix and component B are mixed uniformly in proportion, and cured at room temperature. During the curing process, the drawing time and the surface drying time are recorded as a basis for judging the reaction speed, thereby obtaining a polyurethane adhesive.

[0133] Application Comparative Example 2

[0134] Component A: 50g castor oil, 50g dioctyl terephthalate, 100g calcium carbonate, 0.1% defoamer accounting for the total weight of polyurethane, and 0.04g organotin catalyst;

[0135] Component B: PM-200 20g;

[0136] (1) Mix the raw materials of component A in proportion, stir evenly, heat to 110°C and remove water by vacuum distillation to ensure that the moisture content is less than 0.05%. After the moisture content is qualified, cool to room temperature for use to obtain a premix;

[0137] (2) The premix and component B are mixed uniformly in proportion, and cured at room temperature. During the curing process, the drawing time and the surface drying time are recorded as a basis for judging the reaction speed, thereby obtaining a polyurethane adhesive.

[0138] The recorded results show that the drawing time of the vegetable oil polyol system of Application Example 2 is 55 minutes, and the surface drying time is 5 hours. The drawing time of the castor oil system of Comparative Example 2 is 40 minutes, and the surface drying time is 3.5 hours. This shows that after the addition of the plasticizer dioctyl terephthalate and the inorganic filler calcium carbonate, the reaction activity of the vegetable oil polyol is relatively slow. The reaction activity can be adjusted by adding a catalyst according to the needs of different industries.

[0139] Application Example 3

[0140] Formula: R=1.1

[0141] Component A: 50g of vegetable oil polyol from Example 1, 50g of dioctyl terephthalate, and 0.04g of organotin catalyst;

[0142] Component B: liquefied MDI 20g;

[0143] (1) Mix the raw materials of component A in proportion, stir evenly, heat to 110°C and remove water by vacuum distillation to ensure that the moisture content is less than 0.05%. After the moisture content is qualified, cool to room temperature for use to obtain a premix;

[0144] (2) The premix and component B were mixed evenly in proportion, poured into 8 plastic cups, each with a material thickness of 5 mm, and cured at room temperature for 72 hours before being placed in a constant temperature and humidity chamber for testing to obtain a polyurethane adhesive.

[0145] Application Comparative Example 3

[0146] Formula: R=1.1

[0147] Component A: 50g castor oil, 50g dioctyl terephthalate, 0.04g organotin catalyst;

[0148] Component B: liquefied MDI 20g;

[0149] (1) Mix the raw materials of component A in proportion, stir evenly, heat to 110°C and remove water by vacuum distillation to ensure that the moisture content is less than 0.05%. After the moisture content is qualified, cool to room temperature for use to obtain a premix;

[0150] (2) The premix and component B were mixed evenly in proportion, poured into 8 plastic cups, each with a material thickness of 5 mm, and cured at room temperature for 72 hours before being placed in a constant temperature and humidity chamber for testing to obtain a polyurethane adhesive.

[0151] The Shore hardness and tensile properties of the polyurethane adhesives prepared in Application Example 1 and Comparative Example 1 of the present invention were tested. The testing method was as follows: the polyurethane prepared in Application Example 1 or Comparative Example 1 was poured into a polytetrafluoroethylene dumbbell-shaped mold for curing. The total length of the mold was 160 mm, the width of the parallel section was 10 mm, the length of the parallel section was 60 mm, the clamping gauge length of the tensile testing machine was 50 mm, and the depth was 4 mm. After standing at room temperature for 72 hours, the Shore hardness and tensile properties were tested. The results are shown in Table 1.

[0152] Table 1 Shore hardness and tensile properties of vegetable oil polyols and castor oil in Example 1

[0153] Polyol types Shore A hardness Elongation at break / % Tensile strength / MPa Vegetable oil polyols 68 57.49 3.37 castor oil 65 39.10 1.80

[0154] According to Table 1, the Shore hardness of the vegetable oil polyol adhesive is not much different from that of the castor oil system, but the elongation at break and tensile strength of the vegetable oil polyol adhesive are significantly better than those of the castor oil system.

[0155] The bonding performance of the polyurethane adhesive prepared in Application Example 1 and Comparative Example 1 of the present invention on the aluminum sheet was tested. The test method was as follows: an aluminum sheet made of 3003 material, 100 mm long, 25 mm wide, and 2 mm thick, was selected and polished with sandpaper before use to roughen the surface. The polishing length was 15 mm from one end of the aluminum sheet. A bonding line was drawn on the polished aluminum sheet at 12.5 mm from the roughened portion, and a clamping line was drawn on the other end at 37.5 mm. The prepared adhesive was bonded to the bonding line of the roughened portion of the two aluminum sheets, i.e., the bonding area was 25 mm * 12.5 mm. The sheets were clamped with a clamp and waited for curing. The sheets were placed at room temperature and the tensile shear strength was tested on the 1st, 3rd, and 7th days, respectively. The results are shown in Table 2.

[0156]

[0157]

[0158] According to Table 2, the bonding performance of vegetable oil polyol adhesive to aluminum sheet is significantly better than that of castor oil adhesive.

[0159] The polyurethane adhesives prepared in Application Example 3 and Comparative Example 3 of the present invention were tested for aging resistance. The test conditions were: a constant temperature and humidity test chamber with a set temperature of 85°C and a humidity of 85%. The test time was more than 1000 hours, and samples were taken every 200 hours to test aging resistance. After sampling in each time period, the Shore hardness, color changes, and whether there was cracking were observed. The results are shown in Table 3.

[0160] Table 3 Aging resistance of polyurethane adhesives in Application Example 3 and Comparative Example 3

[0161]

[0162]

[0163] According to Table 3, the Shore hardness of the vegetable oil polyol adhesive was 24.5A before aging, and dropped to 10A after aging for 1400 hours, a decrease of 60%; the Shore hardness of the castor oil adhesive was 37A before aging, and dropped to 0A after aging for 1400 hours, a decrease of 100%; the color change trends of the two adhesives are basically the same, and no cracking occurs during the aging process; overall, the aging resistance of the vegetable oil polyol adhesive is significantly better than that of the castor oil adhesive.

[0164] As can be seen from the above examples, the tensile properties, Shore hardness, bonding properties and aging resistance of the polyurethane material synthesized by the vegetable oil polyol provided by the present invention are all superior to those of the castor oil polyurethane material. The vegetable oil polyol provided by the present invention can replace castor oil and also has the advantage of low cost.

[0165] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing vegetable oil polyols, characterized in that: The following steps are involved: (1) Oleic acid and trimethylolpropane are mixed and subjected to esterification reaction to obtain trimethylolpropane oleate, the structure of which is shown in Formula I: Formula I; (2) Trimethylolpropane oleate, an acid solution, and a hydrogen peroxide solution are mixed to carry out an epoxidation reaction to obtain epoxy trimethylolpropane oleate, the structure of which is shown in Formula II: Formula II; (3) Trimethylolpropane epoxyoleate and sulfuric acid solution are mixed to undergo a ring-opening reaction to obtain a vegetable oil polyol having a structure shown in Formula III: Formula III; The esterification reaction is a multi-stage reaction with a temperature distribution of 160-230°C. The total holding time of the esterification reaction is 8-16 hours. The esterification reaction is carried out in a protective atmosphere. The temperature of the esterification reaction is obtained by temperature programming, wherein the temperature programming comprises: mixing oleic acid and trimethylolpropane and heating and keeping the mixture in sequence for a first heating reaction, a second heating reaction, a third heating reaction, and a fourth heating reaction; The temperature of the first heating reaction is 160~170℃, and the holding time is 1~2 hours; The temperature of the second heating reaction is 180~190℃, and the holding time is 1~2 hours; The temperature of the third heating reaction is 200-210°C, and the holding time is 1-2 h; The temperature of the fourth heating reaction is 220-230°C, and the holding time is 5-10 hours; The epoxidation reaction temperature is 60-80 °C, and the holding time is 4-10 h; The temperature of the ring-opening reaction is 95-107 °C, and the holding time is 4-8 h; In step (1), the mass ratio of oleic acid to trimethylolpropane is 700-900:210-270; In step (2), the mass ratio of trimethylolpropane oleate to the acid solution is 1000:12-20, and the acid in the acid solution is formic acid or acetic acid; The mass concentration of the acid solution is 80~100%; The mass ratio of trimethylolpropane oleate and hydrogen peroxide solution is 1000:120~200; The mass concentration of hydrogen peroxide solution is 30~70%.

2. The preparation method according to claim 1, characterized in that In step (3), the mass ratio of trimethylolpropane epoxyoleate to concentrated sulfuric acid in the sulfuric acid solution is 1000:1-1.8; The mass concentration of the sulfuric acid solution is 0.5-1.5%.

3. Use of the vegetable oil polyol represented by formula III obtained by the preparation method according to claim 1 or 2 in the synthesis of polyurethane, characterized in that: The following steps are involved: (1) Mixing vegetable oil polyol, plasticizer, inorganic filler, defoamer and catalyst and removing water to obtain a premix; (2) The premix and the compound containing an isocyanate group are mixed to undergo a curing reaction to obtain polyurethane.

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