Polyester polyol for PUR wood glue, preparation method of polyester polyol, PUR wood glue and preparation method of PUR wood glue

Abstract

The invention relates to polyester polyol for PUR wood glue, a preparation method of the polyester polyol, the PUR wood glue and a preparation method of the PUR wood glue. The invention relates to polyester polyol for PUR (Polyurethane) wood glue. The polyester polyol comprises strong crystallization type polyester polyol, weak crystallization type polyester polyol and amorphous polyester polyol, the strong crystallization type polyester polyol is selected from at least one of first crystallization type polyester polyol and second crystallization type polyester polyol; the weak crystallization type polyester polyol is selected from at least one of third crystallization type polyester polyol and fourth crystallization type polyester polyol. According to the polyester polyol for the PUR wood glue, provided by the technical scheme of the invention, the combination of the components and the mass part ratio range of the components are determined through a large number of tests; according to the technical scheme, the PUR wood glue prepared from the polyester polyol for the PUR wood glue has better tensile shear strength and viscosity, moderate opening time, low cost and better comprehensive performance, and is beneficial to wide application.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, and in particular to a polyester polyol for PUR wood glue and a preparation method thereof, and PUR wood glue and a preparation method thereof. Background Art

[0002] Due to the rapid development of my country's wood industry, especially the current automobile industry, high-speed rail manufacturing industry, civil and military aircraft manufacturing industry, shipbuilding industry and construction industry, housing furniture, tourist attractions and various industries have developed rapidly in the past decade, and the demand for wood has been even more rapid. However, most domestic companies use purchased varieties of polyester polyols for the preparation of wood adhesives. Most of them are from Germany and Japan. The cost of using these purchased polyester polyols is too high and difficult to modify, resulting in a high cost of the obtained wood adhesive, and the performance sometimes cannot meet customer needs. Summary of the invention

[0003] Based on this, it is necessary to provide a low-cost polyester polyol for PUR wood glue and a preparation method thereof, PUR wood glue and a preparation method thereof that can produce PUR wood glue with good comprehensive performance.

[0004] A polyester polyol for PUR wood glue, wherein the polyester polyol comprises a strongly crystalline polyester polyol, a weakly crystalline polyester polyol and an amorphous polyester polyol;

[0005] The strongly crystalline polyester polyol is selected from at least one of a first crystalline polyester polyol and a second crystalline polyester polyol;

[0006] The raw materials for preparing the first crystalline polyester polyol include the following components in parts by mass:

[0007] Mix 100 parts of carboxylic acid;

[0008] 54 to 57 parts of 1,6-hexanediol; and

[0009] 32 to 34 parts of neopentyl glycol;

[0010] The raw materials for preparing the second crystalline polyester polyol include the following components in parts by mass:

[0011] Mix 100 parts of carboxylic acid;

[0012] 21 to 22 parts of 1,4-butanediol; and

[0013] 34 to 35 parts of ethylene glycol;

[0014] Wherein, in the raw materials for preparing the first crystalline polyester polyol and the raw materials for preparing the second crystalline polyester polyol, the mixed carboxylic acid comprises adipic acid and maleic acid, and the mass ratio of the adipic acid to the maleic acid is (11-15):(5-9);

[0015] The weakly crystalline polyester polyol is selected from at least one of a third crystalline polyester polyol and a fourth crystalline polyester polyol;

[0016] The raw materials for preparing the third crystalline polyester polyol include the following components in parts by mass:

[0017] Adipic acid 100 parts;

[0018] 34 to 35 parts of 1,6-hexanediol; and

[0019] 46 to 47 parts of diethylene glycol;

[0020] The raw materials for preparing the fourth crystalline polyester polyol include the following components in parts by mass:

[0021] Adipic acid 100 parts;

[0022] 44 to 45 parts of 1,4-butanediol; and

[0023] Neopentyl glycol 22 to 23 parts;

[0024] The raw materials for preparing the amorphous polyester polyol include the following components in parts by mass:

[0025] Adipic acid 100 parts;

[0026] 39 to 40 parts of ethylene glycol; and

[0027] 1,2-propylene glycol 5 to 6 parts.

[0028] In the polyester polyol for PUR wood glue of the technical solution of the present invention, the strongly crystalline polyester polyol, the weakly crystalline polyester polyol and the amorphous polyester polyol in the above-mentioned components and mass fraction ranges can be combined to prepare PUR wood glue with good performance. The combination of these components and the above-mentioned mass fraction ranges of each component are determined through a large number of experiments, so that the PUR wood glue prepared by the polyester polyol for PUR wood glue of the technical solution of the present invention has excellent tensile shear strength, viscosity and moderate open time, low cost and good comprehensive performance, which is conducive to wide application.

[0029] In a feasible implementation, the mass ratio of the strongly crystalline polyester polyol, the weakly crystalline polyester polyol and the amorphous polyester polyol is (3-17): (3-17): (9-13).

[0030] In a feasible implementation, the raw materials for preparing the first crystalline polyester polyol include adipic acid, maleic acid, 1,6-hexanediol and neopentyl glycol, and the mass ratio of the adipic acid, the maleic acid, the 1,6-hexanediol and the neopentyl glycol is (74.5952:25.4048:55.5567:32.6508, 74.5952:25.4048:54.9876:32.3164) or (55.7208:44.2792:56.9864:33.4912);

[0031] The raw materials for preparing the second crystalline polyester polyol include adipic acid, maleic acid, 1,4-butanediol and ethylene glycol. The mass ratio of the adipic acid, maleic acid, 1,4-butanediol and ethylene glycol is (55.7208:44.2792:21.4859:34.5538) or (55.7208:44.2792:21.3106:34.2720).

[0032] In a feasible implementation, the raw materials for preparing the third crystalline polyester polyol include adipic acid, 1,6-hexanediol and diethylene glycol, and the mass ratio of the adipic acid, the 1,6-hexanediol and the diethylene glycol is (100:34.678:46.693), (100:34.371:46.414) or (100:34.199:46.0476);

[0033] The raw materials for preparing the fourth crystalline polyester polyol include adipic acid, 1,4-butanediol and neopentyl glycol, and the mass ratio of the adipic acid, the 1,4-butanediol and the neopentyl glycol is 100:44.800:22.205.

[0034] In a feasible implementation, the raw materials for preparing the amorphous polyester polyol include adipic acid, ethylene glycol and 1,2-propylene glycol, and the mass ratio of the adipic acid, the ethylene glycol and the 1,2-propylene glycol is (100:39.607:5.3929), (100:39.942:5.438) or (100:39.75:5.412).

[0035] A method for preparing any of the above-mentioned polyester polyols for PUR wood glue, wherein the polyester polyols include strongly crystalline polyester polyols, weakly crystalline polyester polyols and amorphous polyester polyols, and the preparation method of the strongly crystalline polyester polyols, the weakly crystalline polyester polyols or the amorphous polyester polyols comprises the following steps:

[0036] In a protective gas atmosphere, the carboxylic acid and the diol are uniformly mixed and then heated to 220°C to 230°C, the top temperature of the distillation tower is controlled to be 100°C to 102°C, and after the theoretical water output is completed, the heat preservation treatment is carried out, and then the introduction of the protective gas is stopped; the water generated by the reaction is removed by vacuum to obtain a strongly crystalline polyester polyol, a weakly crystalline polyester polyol or an amorphous polyester polyol.

[0037] The preparation method of the polyester polyol for PUR wood glue of the technical solution of the present invention is simple in process. It has been verified through experiments that the polyester polyol for PUR wood glue prepared by the above preparation method is suitable for PUR wood glue. The PUR wood glue prepared by the polyester polyol for PUR wood glue of the technical solution of the present invention has excellent tensile shear strength, viscosity and moderate open time, low cost and good comprehensive performance, which is conducive to wide application.

[0038] A PUR wood glue, wherein the raw materials for preparing the PUR wood glue include any one of the above polyester polyols, tetrahydrofuran polyol and diphenylmethane diisocyanate.

[0039] The PUR wood glue of the technical solution of the present invention includes the above-mentioned polyester polyol. Through experiments and verification, the PUR wood glue of the present invention has excellent tensile shear strength, viscosity and moderate open time, low cost and good comprehensive performance, which is conducive to wide application.

[0040] In a feasible implementation, the mass ratio of the polyester polyol, the tetrahydrofuran polyol and the diphenylmethane diisocyanate is (29-36): (17-19): (9-10);

[0041] The tetrahydrofuran polyol comprises polytetrahydrofuran diol with a molecular weight of 1000 and polytetrahydrofuran diol with a molecular weight of 2000, and the mass ratio of the polytetrahydrofuran diol with a molecular weight of 1000 to the polytetrahydrofuran diol with a molecular weight of 2000 is (44-47): (44-47).

[0042] In a feasible implementation, the raw material for preparing the PUR wood glue further includes a thickener, the mass ratio of the thickener to the polyester polyol is (11-14): (29-36), and the thickener is polyvinyl alcohol;

[0043] The raw materials for preparing the PUR wood glue also include a tackifier, and the mass ratio of the tackifier to the polyester polyol is (22-24): (29-36); the tackifier includes C5, N120 and N150, and the mass ratio of the C5, the N120 and the N150 is (10-13): (45-55): (45-60);

[0044] The raw materials for preparing the PUR wood glue also include an accelerator, and the mass ratio of the accelerator to the polyester polyol is (0.02-0.03):(145-180); the accelerator is dimorpholine diethyl ether.

[0045] A method for preparing any of the above-mentioned PUR wood glues comprises the following steps:

[0046] Dehydrating tetrahydrofuran polyol and polyester polyol respectively to obtain dehydrated tetrahydrofuran polyol and dehydrated polyester polyol; and

[0047] Diphenylmethane diisocyanate is heated and dissolved to obtain liquid diphenylmethane diisocyanate, and then the dehydrated tetrahydrofuran polyol and the dehydrated polyester polyol are added according to the measured value and mixed evenly, and the PUR wood glue is obtained after sufficient reaction at a temperature of 125° C. to 135° C.

[0048] The preparation method of the PUR wood glue of the technical solution of the present invention is simple in process. Through experiments and verification, the PUR wood glue prepared by the above preparation method has the advantages of excellent tensile shear strength, viscosity and moderate open time, low cost and good comprehensive performance, which is conducive to wide application.

[0049] In a feasible implementation, the polyester polyol includes a strongly crystalline polyester polyol, a weakly crystalline polyester polyol and an amorphous polyester polyol, and the preparation method of the strongly crystalline polyester polyol, the weakly crystalline polyester polyol or the amorphous polyester polyol includes the following steps:

[0050] In a protective gas atmosphere, the carboxylic acid and the diol are uniformly mixed and then heated to 220°C to 230°C, the top temperature of the distillation tower is controlled to be 100°C to 102°C, and after the theoretical water output is completed, the heat preservation treatment is carried out, and then the introduction of the protective gas is stopped; the water generated by the reaction is removed by vacuum to obtain a strongly crystalline polyester polyol, a weakly crystalline polyester polyol or an amorphous polyester polyol. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The present invention is a flowchart of a method for preparing PUR wood glue according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0054] The raw materials of wood come from various resins, such as pine, elm, mahogany, etc. The present invention has conducted relevant research on the performance of elm products and mahogany products through understanding the products of the bonded materials, namely the wood products.

[0055] Generally, wood has a high moisture content. If the moisture content is too high, the quality of the wood being bonded will be affected. If the moisture content is too low, the wood will crack. Therefore, when using, it should be dried first to make its moisture content within the range of 12% to 15%. On this basis, the inventors of the present invention studied polyester polyols.

[0056] The polyester polyol for PUR wood glue according to one embodiment of the present invention includes a strongly crystalline polyester polyol, a weakly crystalline polyester polyol and an amorphous polyester polyol.

[0057] The strongly crystalline polyester polyol is selected from at least one of a first crystalline polyester polyol and a second crystalline polyester polyol.

[0058] Wherein, the raw materials for preparing the first crystalline polyester polyol include the following components in parts by mass:

[0059] Mix 100 parts of carboxylic acid;

[0060] 54 to 57 parts of 1,6-hexanediol; and

[0061] Neopentyl glycol 32 to 34 parts.

[0062] Among them, the raw materials for preparing the second crystalline polyester polyol include the following components in terms of mass fraction:

[0063] Mix 100 parts of carboxylic acid;

[0064] 21 to 22 parts of 1,4-butanediol; and

[0065] 34 to 35 parts of ethylene glycol.

[0066] Among them, in the raw materials for preparing the first crystalline polyester polyol and the raw materials for preparing the second crystalline polyester polyol, the mixed carboxylic acid includes adipic acid and maleic acid, and the mass ratio of adipic acid to maleic acid is (11-15):(5-9).

[0067] The weakly crystalline polyester polyol is selected from at least one of the third crystalline polyester polyol and the fourth crystalline polyester polyol.

[0068] Among them, the raw materials for preparing the third crystalline polyester polyol include the following components in parts by mass:

[0069] Adipic acid 100 parts;

[0070] 34 to 35 parts of 1,6-hexanediol; and

[0071] 46 to 67 parts of diethylene glycol.

[0072] Among them, the raw materials for preparing the fourth crystalline polyester polyol include the following components in parts by mass:

[0073] Adipic acid 100 parts;

[0074] 44 to 45 parts of 1,4-butanediol; and

[0075] Neopentyl glycol 22 to 23 parts.

[0076] Among them, the raw materials for preparing amorphous polyester polyol include the following components in terms of mass fraction:

[0077] Adipic acid 100 parts;

[0078] 39 to 40 parts of ethylene glycol; and

[0079] 1,2-propylene glycol 5 to 6 parts.

[0080] Among the above raw materials, diols such as ethylene glycol, 1,4-butanediol, and 1,2-propylene glycol are too flexible, resulting in too low strength. They are generally not used alone, but need to be mixed with two diols. For example, ethylene glycol and 1,4-butanediol are symmetrical in structure, and the polyester polyols prepared have obvious crystallinity, which is beneficial to improving the bonding strength. 1,2-propylene glycol is an asymmetric structural raw material, and the corresponding polyurethane resin obtained is non-crystalline. Therefore, 1,2-propylene glycol is mixed with ethylene glycol to obtain an amorphous polyester polyol. The diol prepared by diethylene glycol has better flexibility, so the use of ethylene glycol, propylene glycol and diethylene glycol mixed can improve the mechanical properties of wood. Neopentyl glycol can be used to prepare polyester diols with advantages of corrosion resistance, alkali resistance and hydrolysis resistance. Specifically, for looser wood, polyester polyol has a higher molecular weight and higher flexibility, so adding an appropriate amount of neopentyl glycol ester can improve the heat resistance of the wood, thereby preventing the wood from cracking and being damaged during use. Therefore, neopentyl glycol can utilize the curling of the wood to improve the adhesion of the veneer and is generally used for the edging of wood.

[0081] Among the above raw materials, adipic acid has the advantages of good water resistance and stability; maleic acid has a symmetrical structure and a moderate molecular weight, and is suitable for the polyester polyol of the present invention.

[0082] Among them, the weakly crystalline polyester polyol can also be called semi-crystalline polyester polyol. The molecular weight of the crystalline polyester polyol is preferably 3000 to 4500, and the molecular weight of the amorphous polyester polyol is preferably 4000 to 6000.

[0083] The strongly crystalline polyester polyol, weakly crystalline polyester polyol and amorphous polyester polyol of the above components and mass fraction range can be combined to prepare PUR wood glue with better performance. The combination of these components and the above mass fraction range of each component are determined through a large number of experiments, so that the PUR wood glue prepared by the polyester polyol for PUR wood glue of the technical solution of the present invention has better tensile shear strength, viscosity and moderate open time, low cost and good comprehensive performance, which is conducive to wide application.

[0084] Based on the aforementioned embodiment, the mass ratio of the strongly crystalline polyester polyol, the weakly crystalline polyester polyol and the amorphous polyester polyol is (3-17):(3-17):(9-13).

[0085] On the basis of the above-mentioned embodiment, the raw materials for preparing the first crystalline polyester polyol include adipic acid, maleic acid, 1,6-hexanediol and neopentyl glycol, and the mass ratio of adipic acid, maleic acid, 1,6-hexanediol and neopentyl glycol is (74.5952:25.4048:55.5567:32.6508), (74.5952:25.4048:54.9876:32.3164) or (55.7208:4 4.2792:56.9864:33.4912); the raw materials for preparing the second crystalline polyester polyol include adipic acid, maleic acid, 1,4-butanediol and ethylene glycol, and the mass ratio of adipic acid, maleic acid, 1,4-butanediol and ethylene glycol is (55.7208:44.2792:21.4859:34.5538) or (55.7208:44.2792:21.3106:34.2720).

[0086] On the basis of the above-mentioned implementation mode, the raw materials for preparing the third crystalline polyester polyol include adipic acid, 1,6-hexanediol and diethylene glycol, and the mass ratio of adipic acid, 1,6-hexanediol and diethylene glycol is (100:34.678:46.693), (100:34.371:46.414) or (100:34.199:46.0476); the raw materials for preparing the fourth crystalline polyester polyol include adipic acid, 1,4-butanediol and neopentyl glycol, and the mass ratio of adipic acid, 1,4-butanediol and neopentyl glycol is 100:44.800:22.205.

[0087] Based on the above-mentioned embodiment, the raw materials for preparing amorphous polyester polyol include adipic acid, ethylene glycol and 1,2-propylene glycol, and the mass ratio of adipic acid, ethylene glycol and 1,2-propylene glycol is (100:39.607:5.3929), (100:39.942:5.438) or (100:39.75:5.412).

[0088] The polyester polyol of the present invention has a fast opening time of only about 15 seconds and a slow opening time of about 1 to 2 minutes, which can avoid the use being affected by too fast an opening time and the bonding effect and efficiency being affected by too long an opening time.

[0089] In the polyester polyol for PUR wood glue of the technical solution of the present invention, the strongly crystalline polyester polyol, the weakly crystalline polyester polyol and the amorphous polyester polyol in the above-mentioned components and mass fraction ranges can be combined to prepare PUR wood glue with good performance. The combination of these components and the above-mentioned mass fraction ranges of each component are determined through a large number of experiments, so that the PUR wood glue prepared by the polyester polyol for PUR wood glue of the technical solution of the present invention has excellent tensile shear strength, viscosity and moderate open time, low cost and good comprehensive performance, which is conducive to wide application.

[0090] A method for preparing a polyester polyol for PUR wood glue according to an embodiment of the present invention, wherein the polyester polyol includes a strongly crystalline polyester polyol, a weakly crystalline polyester polyol and an amorphous polyester polyol, and the method for preparing the strongly crystalline polyester polyol, the weakly crystalline polyester polyol or the amorphous polyester polyol includes the following steps:

[0091] In a protective gas atmosphere, the carboxylic acid and the diol are uniformly mixed and then heated to 220°C to 230°C, the top temperature of the distillation tower is controlled to be 100°C to 102°C, and after the theoretical water output is completed, the heat preservation treatment is carried out, and then the introduction of the protective gas is stopped; the water generated by the reaction is removed by vacuum to obtain a strongly crystalline polyester polyol, a weakly crystalline polyester polyol or an amorphous polyester polyol.

[0092] In the above steps, carboxylic acid refers to adipic acid and / or maleic acid, and diol refers to 1,6-hexanediol, neopentyl glycol, 1,4-butanediol, ethylene glycol, diethylene glycol and / or 1,2-propylene glycol. The specific raw material components and proportions of carboxylic acid and diol are not limited here, and the specific added components and proportions in this step are set according to the above formula.

[0093] In the above step of preparing polyester polyol, the operation of uniformly mixing carboxylic acid and diol is: firstly put carboxylic acid into the reactor, then add diol and close the feeding cover. Further, after the reactants are heated to melt, a small amount of (or no) catalyst is added with a stirrer, and a protective gas is introduced. The protective gas can prevent air from entering the reactor, and the protective gas is preferably nitrogen.

[0094] In the above steps of preparing polyester polyols, during the heating process, water starts to flow out when the temperature in the reactor reaches about 150°C, and the temperature at the top of the distillation tower is controlled at 100°C to 102°C. The temperature in the reactor is continued to be increased until about 220°C, and the theoretical water output is completed (the water output time is usually 8h to 10h). After the theoretical water output is completed, the insulation time is 2h to 4h.

[0095] In the above steps of preparing polyester polyol, the vacuum degree of vacuuming is about 0.1 MPa. Depending on the molecular weight of the polyester polyol, the high vacuum time of polyester is 7h to 9h.

[0096] Furthermore, the present invention provides a series of novel polyester polyols for PUR wood glue (referred to as CJW-90 series) and a preparation method thereof. The raw materials are weighed according to Table 1, and the preparation method is as follows:

[0097] In a protective gas atmosphere, the carboxylic acid and the diol are mixed evenly and then heated to 220°C. The top temperature of the distillation tower is controlled at 100°C to 102°C. After the theoretical water output is completed, the heat preservation treatment is carried out, and then the introduction of the protective gas is stopped; the water generated by the reaction is removed by vacuum to obtain polyester polyol.

[0098] Table 1 Specific composition and raw material information of polyester polyols

[0099]

[0100]

[0101]

[0102]

[0103] The above CJW-90 series polyester polyol for PUR wood glue has the following properties:

[0104] Table 2 Performance indexes of CJW-90 series polyester polyols

[0105]

[0106] The preparation method of the polyester polyol for PUR wood glue of the technical solution of the present invention is simple in process. It has been verified through experiments that the polyester polyol for PUR wood glue prepared by the above preparation method is suitable for PUR wood glue. The PUR wood glue prepared by the polyester polyol for PUR wood glue of the technical solution of the present invention has excellent tensile shear strength, viscosity and moderate open time, low cost and good comprehensive performance, which is conducive to wide application.

[0107] In one embodiment of the PUR wood glue, the raw materials for preparing the PUR wood glue include any one of the above polyester polyols, tetramethylene glycol (PTMEG) and diphenylmethane diisocyanate (MDI).

[0108] Wherein, the structural formula of polytetrahydrofuran diol is as follows:

[0109]

[0110] The use of polytetramethylene glycol can improve the cold resistance and water resistance of wood. The combination of tetramethylene glycol and polyester polyol is beneficial to improving the mechanical properties of PUR wood glue for woodworking, while maintaining the excellent low temperature resistance, water resistance, oil resistance, wear resistance and mildew resistance brought by tetramethylene glycol.

[0111] Among them, diphenylmethane diisocyanate is a white solid crystal with low toxicity and low irritating odor. Further, diphenylmethane diisocyanate preferably uses MDI-100, which has excellent yellowing resistance and is suitable for high-grade wood products.

[0112] Based on the above-mentioned embodiment, the mass ratio of polyester polyol, tetrahydrofuran polyol and diphenylmethane diisocyanate is (29-36): (17-19): (9-10).

[0113] When the polyester polyol of the present invention is applied to PUR wood glue, MDI diisocyanate and polytetrahydrofuran diol are preferably used. MDI diisocyanate has excellent properties, and polytetrahydrofuran diol and polyester polyol participate in the reaction synergistically, which significantly improves the properties of the polyester polyol.

[0114] On the basis of the above-mentioned embodiment, the tetrahydrofuran polyol includes polytetrahydrofuran diol with a molecular weight of 1000 and polytetrahydrofuran diol with a molecular weight of 2000, and the mass ratio of polytetrahydrofuran diol with a molecular weight of 1000 to polytetrahydrofuran diol with a molecular weight of 2000 is (44-47): (44-47). The mixed use of polytetrahydrofuran diol with a molecular weight of 1000 and polytetrahydrofuran diol with a molecular weight of 2000 can reduce the viscosity of PUR monomer, thereby improving the flexibility of PUR. The PUR hot melt adhesive prepared according to the above mass ratio has excellent low temperature resistance, water resistance, oil resistance, wear resistance and mildew resistance.

[0115] On the basis of the above-mentioned embodiment, the raw materials for preparing PUR wood glue also include a thickener, the mass ratio of the thickener to the polyester polyol is (11-14): (29-36), and the thickener is polyvinyl alcohol. Polyvinyl alcohol EVA is beneficial to improving the bonding strength and adhesion of the hot melt adhesive.

[0116] On the basis of the above-mentioned embodiment, the raw materials for preparing PUR wood glue further include a tackifier, and the mass ratio of the tackifier to the polyester polyol is (22-24): (29-36); the tackifier includes C5, N120 and N150, and the mass ratio of C5, N120 and N150 is (10-13): (45-55): (45-60). Among them, C5, N120 and N150 are all polycarbonate resins.

[0117] On the basis of the above-mentioned embodiment, the raw materials for preparing PUR wood glue further include an accelerator, and the mass ratio of the accelerator to the polyester polyol is (0.02-0.03):(145-180); the accelerator is dimorpholine diethyl ether.

[0118] The PUR wood glue of the technical solution of the present invention includes the above-mentioned polyester polyol. Through experiments and verification, the PUR wood glue of the present invention has excellent tensile shear strength, viscosity and moderate open time, low cost and good comprehensive performance, which is conducive to wide application.

[0119] See also Figure 1 The preparation method of PUR wood glue according to one embodiment of the present invention comprises the following steps:

[0120] S10, respectively dehydrating tetrahydrofuran polyol and polyester polyol to obtain dehydrated tetrahydrofuran polyol and dehydrated polyester polyol.

[0121] The temperature for dehydrating tetrahydrofuran polyol is 100°C to 120°C, and the temperature for dehydrating polyester polyol is 130°C to 140°C.

[0122] S20, heating and dissolving diphenylmethane diisocyanate to obtain liquid diphenylmethane diisocyanate, then adding dehydrated tetrahydrofuran polyol and dehydrated polyester polyol according to the measured value, mixing, and fully reacting at a temperature of 125° C. to 135° C. to obtain PUR wood glue.

[0123] Wherein, in step S20, MDI is added first and then polyester polyol is added. After heating reaction, no particles and gel blocks will be generated, otherwise particles will definitely be generated.

[0124] The time for sufficient reaction at a temperature of 125°C to 135°C is 20 minutes to 60 minutes.

[0125] Furthermore, in the preparation method of PUR wood glue of the present invention, the raw materials may also include additives such as thickeners, tackifiers and catalysts. In this case, in step S20, the above additives are evenly mixed with the dehydrated tetrahydrofuran polyol and the dehydrated polyester polyol, and the PUR wood glue is obtained after sufficient reaction.

[0126] The PUR wood glue obtained in step S20 is a moisture-curing reactive polyurethane hot melt adhesive. The advantage of the PUR wood glue prepared by using the multifunctional, high-performance polyester polyol is that it combines the bonding speed of traditional hot melt adhesives with the viscosity and strength of reactive adhesives.

[0127] The preparation method of the PUR wood glue of the technical solution of the present invention is simple in process. Through experiments and verification, the PUR wood glue prepared by the above preparation method has the advantages of excellent tensile shear strength, viscosity and moderate open time, low cost and good comprehensive performance, which is conducive to wide application.

[0128] With reference to the above implementation contents, in order to make the technical solution of the present invention more specific, clear and easy to understand, the technical solution of the present invention is now exemplified. However, it should be noted that the contents to be protected by the present invention are not limited to the following embodiments.

[0129] The raw materials used in the following examples include: diphenylmethane diisocyanate MDI-100, produced by Japan Polyurethane Industry Co., Ltd.; polytetrahydrofuran diol PTMEG-1000, in liquid form, with a functionality of 2, produced by Yangzhou Synthetic Chemical Plant; PTMEG-2000, in liquid form, with a functionality of 2, produced by Yangzhou Synthetic Chemical Plant; polyvinyl alcohol EVA-456, produced by Shanghai Petrochemical Co., Ltd.; polyvinyl alcohol EVA-742, produced by Shanghai Petrochemical Co., Ltd.; polycarbonate resin C5-5#, produced by Qianxu Chemical Plant, Jinshan District, Shanghai; polycarbonate resin TN-120, produced by Tangshan New District Chemical Resin Plant; polycarbonate resin TN-150, produced by Tangshan New District Chemical Resin Plant; dimorpholine diethyl ether DMDEE, produced by Shanghai Nanxiang Reagent Co., Ltd.

[0130] Embodiment 1 to Embodiment 3

[0131] Examples 1 to 3 respectively provide a polyester polyol for PUR wood glue and a preparation method thereof and PUR wood glue and a preparation method thereof. The raw materials are weighed according to Table 3.

[0132] The preparation method of polyester polyol for PUR wood glue is as follows:

[0133] In a protective gas atmosphere, carboxylic acid and diol are mixed evenly and then heated to 220°C. The top temperature of the distillation tower is controlled at 100°C to 102°C. After the theoretical water output is completed, insulation treatment is performed and then the introduction of protective gas is stopped. Vacuum is applied to remove the moisture generated by the reaction to obtain polyester polyols of various grades.

[0134] The preparation method of PUR wood glue is as follows:

[0135] 1. Provide 3 reactors, including 2 upper reactors and 1 lower reactor;

[0136] 2. PTMEG is placed in the upper reactor (1) and heated, dehydrated at 120°C for 2 hours, and then set aside.

[0137] 3. Add the polyester polyol into the upper reactor (2), dissolve and dehydrate at a dissolving temperature of 140°C for 2 hours, and set aside;

[0138] 4. Add MDI into the lower reactor and heat it to 80°C to dissolve it into liquid;

[0139] 5. Add the dehydrated PTMEG into the lower reactor according to the metered amount, and the lower reactor should be in an open state;

[0140] 6. Add the polyester polyol obtained in step 3 into the lower reactor according to the measured value. The lower reactor should be turned on in a stirring state and react for 40 minutes at a reaction temperature of 130°C;

[0141] 7. Add thickener, tackifier and catalyst into the lower reactor for stirring;

[0142] 8. After the reaction is completed, the product is placed in an aluminum bag and protected with nitrogen.

[0143] Table 3 Raw materials of polyester polyol for PUR wood glue and PUR wood glue of Example 1 to Example 3

[0144]

[0145] The isocyanate content (NCO) in the PUR wood glue of Example 1 is calculated as follows:

[0146] NCO%=MDI-PTMEG-PTMEG-CJW-9012-CJW-9014-CJW-9026=1.337%;

[0147] The calculation of the isocyanate content (NCO) in the PUR wood glue of Example 2 is as follows:

[0148] NCO%=MDI-PTMEG-PTMEG-CJW-9010-CJW-9016-CJW-9028=1.331%;

[0149] The calculation of the isocyanate content (NCO) in the PUR wood glue of Example 3 is as follows:

[0150] NCO%=MDI-PTMEG-PTMEG-CJW-9020-CJW-9024-CJW-9030=1.339%.

[0151] Performance Test:

[0152] 1. The PUR wood glue of Examples 1 to 3 was tested as follows. The test method is as follows. The performance indicators of the PUR wood glue are shown in Table 4.

[0153] ① Determination of open time: Touch lightly with your finger and the surface should not be sticky.

[0154] ② Determination of tensile shear strength: the test method is: test according to GB / T 7124-2008 Determination of tensile shear strength of adhesives (rigid material to rigid material);

[0155] ③ Determination of viscosity: the test method is: test according to HG / T 3660-1999 Determination of melt viscosity of hot melt adhesives.

[0156] ④ Determine the isocyanate content of PUR wood glue. Test method: Test according to "Determination of Isocyanate Content in Polymethylene Polyphenyl Isocyanate" (GB / T 12009.4-1989).

[0157] Table 4 Performance test data of PUR wood glue of Example 1 to Example 3

[0158]

[0159] As can be seen from Table 4, the viscosity of the PUR wood glue of Examples 1 to 3 of the present invention is moderate, and it is suitable for wood glue; the open time is moderate, which can avoid the open time being too fast to affect the use, and can avoid the open time being too long to affect the bonding effect and bonding efficiency; the tensile shear strength is good, indicating that the bonding force is good, and it is suitable for wood glue; the content of isocyanate groups is not much different from the theoretical content. The above shows that the PUR wood glue of Examples 1 to 3 of the present invention has low cost and good comprehensive performance, which is conducive to wide application.

[0160] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0161] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A polyester polyol for PUR wood glue, characterized in that: The polyester polyols include strongly crystalline polyester polyols, weakly crystalline polyester polyols and amorphous polyester polyols; The strongly crystalline polyester polyol is selected from at least one of a first crystalline polyester polyol and a second crystalline polyester polyol; The raw materials for preparing the first crystalline polyester polyol include the following components in parts by mass: Mix 100 parts of carboxylic acid; 54 to 57 parts of 1,6-hexanediol; and 32 to 34 parts of neopentyl glycol; The raw materials for preparing the second crystalline polyester polyol include the following components in parts by mass: Mix 100 parts of carboxylic acid; 21 to 22 parts of 1,4-butanediol; and 34 to 35 parts of ethylene glycol; Wherein, in the raw materials for preparing the first crystalline polyester polyol and the raw materials for preparing the second crystalline polyester polyol, the mixed carboxylic acid comprises adipic acid and maleic acid, and the mass ratio of the adipic acid to the maleic acid is (11-15):(5-9); The weakly crystalline polyester polyol is selected from at least one of a third crystalline polyester polyol and a fourth crystalline polyester polyol; The raw materials for preparing the third crystalline polyester polyol include the following components in parts by mass: Adipic acid 100 parts; 34 to 35 parts of 1,6-hexanediol; and 46 to 47 parts of diethylene glycol; The raw materials for preparing the fourth crystalline polyester polyol include the following components in parts by mass: Adipic acid 100 parts; 44 to 45 parts of 1,4-butanediol; and Neopentyl glycol 22 to 23 parts; The raw materials for preparing the amorphous polyester polyol include the following components in parts by mass: Adipic acid 100 parts; 39 to 40 parts of ethylene glycol; and 1,2-propylene glycol 5 to 6 parts.

2. The polyester polyol for PUR wood glue according to claim 1, characterized in that: The mass ratio of the strongly crystalline polyester polyol, the weakly crystalline polyester polyol and the amorphous polyester polyol is (3-17): (3-17): (9-13).

3. The polyester polyol for PUR wood glue according to claim 1, characterized in that: The raw materials for preparing the first crystalline polyester polyol include adipic acid, maleic acid, 1,6-hexanediol and neopentyl glycol, and the mass ratio of the adipic acid, the maleic acid, the 1,6-hexanediol and the neopentyl glycol is (74.5952:25.4048:55.5567:32.6508, 74.5952:25.4048:54.9876:32.3164) or (55.7208:44.2792:56.9864:33.4912); The raw materials for preparing the second crystalline polyester polyol include adipic acid, maleic acid, 1,4-butanediol and ethylene glycol. The mass ratio of the adipic acid, maleic acid, 1,4-butanediol and ethylene glycol is (55.7208:44.2792:21.4859:34.5538) or (55.7208:44.2792:21.3106:34.2720).

4. The polyester polyol for PUR wood glue according to claim 1, characterized in that: The raw materials for preparing the third crystalline polyester polyol include adipic acid, 1,6-hexanediol and diethylene glycol, and the mass ratio of the adipic acid, the 1,6-hexanediol and the diethylene glycol is (100:34.678:46.693), (100:34.371:46.414) or (100:34.199:46.0476); The raw materials for preparing the fourth crystalline polyester polyol include adipic acid, 1,4-butanediol and neopentyl glycol, and the mass ratio of the adipic acid, the 1,4-butanediol and the neopentyl glycol is 100:44.800:22.

205.

5. The polyester polyol for PUR wood glue according to claim 1, characterized in that: The raw materials for preparing the amorphous polyester polyol include adipic acid, ethylene glycol and 1,2-propylene glycol, and the mass ratio of the adipic acid, the ethylene glycol and the 1,2-propylene glycol is (100:39.607:5.3929), (100:39.942:5.438) or (100:39.75:5.412).

6. A method for preparing the polyester polyol for PUR wood glue according to any one of claims 1 to 5, characterized in that: The polyester polyol includes strongly crystalline polyester polyol, weakly crystalline polyester polyol and amorphous polyester polyol. The preparation method of the strongly crystalline polyester polyol, the weakly crystalline polyester polyol or the amorphous polyester polyol includes the following steps: In a protective gas atmosphere, the carboxylic acid and the diol are uniformly mixed and then heated to 220°C to 230°C, the top temperature of the distillation tower is controlled to be 100°C to 102°C, and after the theoretical water output is completed, the heat preservation treatment is carried out, and then the introduction of the protective gas is stopped; the water generated by the reaction is removed by vacuum to obtain a strongly crystalline polyester polyol, a weakly crystalline polyester polyol or an amorphous polyester polyol.

7. A PUR wood glue, characterized in that: The raw materials for preparing the PUR wood glue include the polyester polyol, tetrahydrofuran polyol and diphenylmethane diisocyanate described in any one of claims 1 to 6.

8. The PUR wood glue according to claim 7, characterized in that: The mass ratio of the polyester polyol, the tetrahydrofuran polyol and the diphenylmethane diisocyanate is (29-36): (17-19): (9-10); The tetrahydrofuran polyol comprises polytetrahydrofuran diol with a molecular weight of 1000 and polytetrahydrofuran diol with a molecular weight of 2000, and the mass ratio of the polytetrahydrofuran diol with a molecular weight of 1000 to the polytetrahydrofuran diol with a molecular weight of 2000 is (44-47): (44-47).

9. The PUR wood glue according to claim 7, characterized in that: The raw materials for preparing the PUR wood glue also include a thickener, the mass ratio of the thickener to the polyester polyol is (11-14): (29-36), and the thickener is polyvinyl alcohol; The raw materials for preparing the PUR wood glue also include a tackifier, and the mass ratio of the tackifier to the polyester polyol is (22-24): (29-36); the tackifier includes C5, N120 and N150, and the mass ratio of the C5, the N120 and the N150 is (10-13): (45-55): (45-60); The raw materials for preparing the PUR wood glue also include an accelerator, and the mass ratio of the accelerator to the polyester polyol is (0.02-0.03):(145-180); the accelerator is dimorpholine diethyl ether.

10. A method for preparing the PUR wood glue according to any one of claims 7 to 9, characterized in that: The steps include: Dehydrating tetrahydrofuran polyol and polyester polyol respectively to obtain dehydrated tetrahydrofuran polyol and dehydrated polyester polyol; and Diphenylmethane diisocyanate is heated and dissolved to obtain liquid diphenylmethane diisocyanate, and then the dehydrated tetrahydrofuran polyol and the dehydrated polyester polyol are added according to the measured value and mixed evenly, and the PUR wood glue is obtained after sufficient reaction at a temperature of 125° C. to 135° C.

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