Polyurethane hot melt adhesive as well as preparation method and application thereof

Abstract

The invention discloses a polyurethane hot melt adhesive and a preparation method and application thereof, the polyurethane hot melt adhesive comprises the following raw materials: polyol, polyisocyanate and p-hydroxyphenyl alkyl alcohol, the polyol comprises polyester polyol, polycarbonate diol, polyolefin diol and polyether diol; the polyester polyol comprises polyester polyol A, polyester diol B and polyester diol C; the raw materials of the polyester polyol A comprise polyacid A and polyol A, the polyacid A is composed of isophthalic acid and adipic acid and / or phthalic anhydride, and the polyol A is composed of hexanediol, neopentyl glycol and trimethylolpropane; the polyester diol B is prepared from alkyl diol and alkyl diacid through a reaction, and the polyester diol C is crystalline polyester diol; the preparation method comprises the following steps: dehydrating polyhydric alcohols and other raw materials, mixing, reacting, and defoaming. The hot melt adhesive disclosed by the invention at least can meet the high-temperature production requirement in summer, is relatively good in temperature resistance, and has the characteristics of no spinning, no wire drawing, less adhesive coating amount and the like.

Description

Technical Field

[0001] The invention relates to the field of adhesives, and in particular to a polyurethane hot melt adhesive and a preparation method and application thereof. Background Art

[0002] At present, under the background of the booming development of the furniture industry, high-end customization has become a trend in the furniture industry. It not only represents consumers' pursuit of individuality and uniqueness, but also an important manifestation of furniture companies' technological innovation and quality improvement. In this trend, board edge banding is an important link in the furniture manufacturing process, and its edge banding details can directly affect consumers' intuitive impression of product quality. Customized furniture edge banding glue is an adhesive specially used for edge banding of artificial boards, among which polyurethane hot melt adhesive has excellent bonding strength, temperature resistance, chemical corrosion resistance and aging resistance.

[0003] Compared with traditional EVA hot melt adhesive, polyurethane hot melt adhesive has better water resistance, durability and cold resistance, the edge banding adhesive line prepared is thinner and more beautiful, and the comprehensive application cost is lower. In addition, this type of polyurethane hot melt adhesive does not contain toxic and harmful volatile chemicals such as formaldehyde and benzene, so it has the characteristics of green and environmental protection. With the continuous development of the custom furniture industry and the increasing demand of consumers, polyurethane hot melt edge banding adhesive has won wide recognition in the market for its excellent performance and green and environmental protection concept.

[0004] However, it is worth noting that in the high-temperature production environment in summer, the initial bonding strength of polyurethane hot melt adhesive may be affected to a certain extent, resulting in problems such as rebound at the end of straight edge banding, which may lead to problems such as reduced product quality, increased production costs, and damage to the brand image of the company.

[0005] It should be noted that the information disclosed in the above background technology section is only used to understand the background of the present application, so the background technology section of the present invention may contain background information about the problem or environment of the present invention, but not necessarily describe the prior art. Therefore, the content contained in the background technology section is not an admission of the applicant to the prior art. Summary of the invention

[0006] The object of the present invention is to overcome one or more deficiencies in the prior art and to provide an improved polyurethane hot melt adhesive which can at least meet the high temperature production requirements in summer.

[0007] The present invention also provides a preparation method of the polyurethane hot melt adhesive and application of the polyurethane hot melt adhesive in edge sealing of panels.

[0008] In order to achieve the above object, a technical solution adopted by the present invention is: a polyurethane hot melt adhesive, the raw materials of the polyurethane hot melt adhesive include:

[0009] 1) polyols, wherein the polyols include polyester polyols, polycarbonate diols, polyolefin diols and polyether diols; the polyester polyols account for more than 70% of the polyols in terms of mass percentage;

[0010] The polyester polyol comprises polyester polyol A, polyester diol B and polyester diol C;

[0011] The polyester polyol A has a branched structure, and the raw materials of the polyester polyol A include polyacid A and polyol A, wherein the polyacid A is composed of isophthalic acid and adipic acid and / or phthalic anhydride, and the polyol A is composed of hexanediol, neopentyl glycol and trimethylolpropane;

[0012] The polyester diol B is prepared by reacting an alkyl diol and an alkyl diacid, and the polyester diol C is a crystalline polyester diol;

[0013] 2) Polyisocyanate;

[0014] 3) Compound represented by formula (I)

[0015] R is C 1-6 alkyl.

[0016] In the present invention, the introduction of polyester polyol A into the system can improve the heat resistance of the polyurethane hot melt adhesive, thereby improving the initial bonding strength between the edge banding strip and the plate after it is unloaded from the machine during the production process in a high temperature environment in summer, and effectively avoiding problems such as the edge banding strip opening as soon as it is pulled and the rebound of the straight edge banding end; moreover, polyester polyol A has a lightly branched structure, which can promote the polyurethane hot melt adhesive to quickly produce a cross-linked network structure during the curing process, thereby promoting a significant increase in the peel strength of the polyurethane hot melt adhesive within 24 hours, and at the same time can also improve the final peel strength. Furthermore, the introduction of the compound represented by formula (I) in the formulation system of the present invention, on the one hand, plays the role of a chain extender. In addition, the hydroxyl groups on both sides of the benzene ring have different activities from isocyanate, and the reaction activity of the phenolic hydroxyl groups is lower than that of the hydroxyl groups of phenylalkyl alcohol and the polymer polyol. This will make the reaction rate of the hydroxyl groups different during the reaction, thereby inducing the polymerization process to tend to pre-polymerize the isocyanate and the polymer polyol first and then extend the chain, which is conducive to the formation of a prepolymer with a larger molecular weight. On the other hand, the compound represented by formula (I) has a benzene ring structure, which can further improve the rigidity of the hard segment, and is easily formed near the end of the molecular chain structure during the reaction, promoting microphase separation, thereby increasing the peel strength.

[0017] In some embodiments of the present invention, the feed mass ratio of the polyester polyol, the polycarbonate diol, the polyolefin diol and the polyether diol is 37-70:3-5:2-4:1.5-5.

[0018] In some embodiments of the present invention, the feed mass ratio of the polyester polyol A, the polyester diol B and the polyester diol C is 12-25:10-15:15-30.

[0019] In some embodiments of the present invention, the hydroxyl value of the polyester polyol A is 32-64 mg KOH / g.

[0020] In some embodiments of the present invention, the hydroxyl value of the polyester diol B is 28-58 mg KOH / g.

[0021] In some embodiments of the present invention, the hydroxyl value of the polyester diol C is 28-56 mg KOH / g.

[0022] In some embodiments of the present invention, the number average molecular weight of the polyester polyol A, the number average molecular weight of the polyester diol B and the number average molecular weight of the polyester diol C are 2000-4000 respectively.

[0023] In some embodiments of the present invention, the polyester polyol A is prepared by reacting the polyacid A and the polyol A. In parts by weight, the raw materials of the polyester polyol A include: 100 parts of polyacid A and 66-75 parts of polyol A.

[0024] In some embodiments of the present invention, in the polyacid A, the molar ratio of the isophthalic acid to the adipic acid and / or phthalic anhydride is 1:0.05-0.3.

[0025] In some embodiments of the present invention, in the polyol A, the molar ratio of the hexylene glycol, the neopentyl glycol and the trimethylolpropane is 1:4-11:0.05-0.3.

[0026] Furthermore, the preparation method of the polyester polyol A comprises: adding the required polyacid, hexylene glycol, neopentyl glycol and trimethylolpropane into a reaction kettle, heating to 170-180° C., starting stirring, introducing protective gas (such as nitrogen, inert gas, etc., inert gas includes argon, helium, etc.), and prepolymerizing for about 1-3 hours; heating by 15-25° C. every 1-3 hours, heating to 210-230° C., and performing ester exchange for 1-3 hours; adding a catalyst (such as tetrabutyl titanate, tetraisopropyl titanate, etc.), turning off the protective gas, reducing the pressure, sampling and analyzing at regular intervals (such as 0.1-2 hours), and when the acid value and hydroxyl value reach the expected values, cooling and discharging to obtain polyester polyol A.

[0027] Furthermore, the acid value of the polyester polyol A is ≤1 mg KOH / g.

[0028] In some embodiments of the present invention, the raw materials of the polyester diol B include polyacid B and polyol B, the polyacid B includes adipic acid, and the polyol B includes 1,4-butanediol and / or 1,6-hexanediol and neopentyl glycol and / or 2-methylpropanediol. Further, the polyester diol B is prepared by polycondensation of polyacid B and polyol B. According to some specific aspects of the present invention, the polyester diol B can be homemade or commercially available.

[0029] According to some specific aspects of the present invention, the preparation method of the polyester diol B includes: adding polyacid B and polyol B into a reaction kettle, heating to 130-150°C, starting stirring, introducing protective gas (such as nitrogen, inert gas, etc., inert gas includes argon, helium, etc.), and prepolymerizing for about 1-3 hours; heating by 15-25°C every 1-3 hours, heating to 210-235°C, and performing ester exchange for 1-3 hours; adding a catalyst (for example, tetrabutyl titanate, tetraisopropyl titanate, etc.), turning off the protective gas, reducing the pressure, sampling and analyzing at regular intervals (for example, 0.1-2 hours), and when the acid value and hydroxyl value reach the expected values ​​(acid value ≤1mgKOH / g, hydroxyl value is 28-58mg KOH / g), cooling and discharging to obtain polyester diol B.

[0030] In some embodiments of the present invention, the raw materials of the polyester diol C include polyacid C and polyol C, the polyacid C is a combination of one or more selected from adipic acid, sebacic acid, and dodecanedioic acid, and the polyol C is a combination of one or more selected from ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and dodecanediol. Further, the polyester diol C is prepared by polycondensation of polyacid C and polyol C. According to some specific aspects of the present invention, the polyester diol C can be homemade or commercially available, for example, Jiangsu Huada CMA-3566 can be selected.

[0031] In some embodiments of the invention, R is methyl, ethyl or propyl.

[0032] In some embodiments of the invention, R is substituted at the para position.

[0033] In some embodiments of the present invention, the mass ratio of the compound represented by formula (I) to the polyol is 0.0035-0.035:1, further 0.005-0.025:1, and further 0.005-0.015:1, in terms of mass percentage.

[0034] In some embodiments of the present invention, the number average molecular weight of the polycarbonate diol is 1000-3000, and the polycarbonate diol can be homemade or commercially available, for example, UBE's UH-200 can be used.

[0035] In some embodiments of the present invention, the polyolefin diol is a combination of one or more selected from polybutadiene diol, hydroxyl-terminated polybutadiene-acrylonitrile, and hydroxyl-terminated hydrogenated polybutadiene.

[0036] Furthermore, the number average molecular weight of the polyolefin diol is 1800-3000.

[0037] According to some specific aspects of the present invention, the polyolefin diol can be self-made or commercially available, for example, Cray Valley LBH-2000, HLBH-P2000, HLBH-P3000, etc. can be selected.

[0038] In some embodiments of the present invention, the polyether diol is polyoxypropylene diol or a combination thereof with polyoxyethylene diol.

[0039] Furthermore, the number average molecular weight of the polyether diol is 400-2000.

[0040] According to some specific aspects of the present invention, the polyether diol can be self-made or commercially available, for example, PEG1000, PPG400, PPG1000, PPG2000, etc. can be selected.

[0041] In some embodiments of the present invention, the raw material of the polyurethane hot melt adhesive further comprises a combination of one or more of an antioxidant, an inhibitor, a tackifying resin, and a filler.

[0042] Furthermore, the antioxidant can be selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 164 and antioxidant 264, and the amount of the antioxidant used accounts for 0.001 to 0.5% of the total raw material amount of the polyurethane hot melt adhesive.

[0043] Furthermore, the polymerization inhibitor is one or more of phosphoric acid and benzoyl chloride, and the dosage of the polymerization inhibitor accounts for 0.0002-0.1% of the total raw material dosage of the polyurethane hot melt adhesive.

[0044] Further, the tackifying resin can be selected from a combination of one or more of polyacrylic acid resin, polyolefin resin and EVA resin; further, the tackifying resin is a combination of polyacrylic acid resin, polyolefin resin and EVA resin in a mass ratio of 3 to 10: 2 to 4: 2 to 4. The tackifying resin has good solubility in polyol according to the mass ratio, so as to effectively improve the overall cohesion of the hot melt adhesive.

[0045] In some embodiments of the present invention, the polyacrylic acid resin can be selected from Japan Mitsubishi BR113, BR116, etc.; the polyolefin resin can be selected from SUNVISTA 666, VESTOPLAST 408, VESTOPLAST 508, etc., the vinyl acetate content in the EVA resin is 20-50%, and the EVA resin can be selected from Japan Tosoh EVA 720, EVA760, Japan Mitsui 40W, etc.

[0046] In some embodiments of the present invention, the filler can be selected from a combination of one or more of calcium carbonate, carbon dioxide, and mica. The filler accounts for 10 to 38% of the total raw material usage of the polyurethane hot melt adhesive, and can further be 15 to 35%. The addition of fillers can reduce the cost of hot melt adhesives and improve the overall mechanical properties of hot melt adhesives. Moreover, the addition of fillers can reduce the degree of glue drawing during the edge banding process and will not dirty the sheet material, thereby eliminating the step of cleaning the sheet material for the edge banding company, improving the production efficiency of the production company and reducing production costs.

[0047] In some embodiments of the present invention, the raw materials of the polyurethane hot melt adhesive include the following components in parts by weight:

[0048]

[0049] In some embodiments of the present invention, the polyisocyanate may be at least one of pure diphenylmethane diisocyanate, MDI-50, liquefied diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,5-naphthalene diisocyanate. The R value of the isocyanate is 1.3 to 2.2. Preferably, the R value of the isocyanate is 1.5 to 2.0.

[0050] Another technical solution provided by the present invention is a method for preparing the polyurethane hot melt adhesive described above, the preparation method comprising:

[0051] The polyol, antioxidant, tackifying resin and filler are uniformly mixed at 140-170° C., cooled to 100-140° C. for dehydration to a moisture content of less than 0.03%, then cooled to 90-110° C., the compound represented by formula (I) and the polymerization inhibitor are added for vacuum dehydration, and then polyisocyanate is added for reaction and degassing to obtain the polyurethane hot melt adhesive.

[0052] Another technical solution provided by the present invention is an application of the above-mentioned polyurethane hot melt adhesive in edge sealing of panels.

[0053] Furthermore, the board material includes plywood, particle board, density board, etc. The edge banding material includes PET, PVC, ABS, etc.

[0054] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0055] The polyurethane hot melt adhesive of the present invention can improve the heat resistance of the polyurethane hot melt adhesive through the design of the formula, thereby improving the edge sealing strength in the high temperature production process in summer, and avoiding the generation of problems such as edge banding rebound and edge warping. In addition, the prepared polyurethane hot melt adhesive has the characteristics of no glue throwing, no wire drawing, and less glue coating, and has good bonding strength for various types of plates and edge banding strips. Moreover, the glue line of the product after edge sealing is thinner and has a good appearance.

[0056] The polyurethane hot melt adhesive of the invention is solvent-free and green and environmentally friendly. DETAILED DESCRIPTION

[0057] The above scheme is further described below in conjunction with specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions adopted in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0058] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0059] Example 1

[0060] This example provides a polyurethane hot melt adhesive and a preparation method thereof, and the preparation method of the polyurethane hot melt adhesive comprises the following steps:

[0061] 1) Weigh 5 parts by weight of 1,6-hexanediol, 95 parts by weight of isophthalic acid, 6.8 parts by weight of 1,6-hexanediol, 61 parts by weight of neopentyl glycol, and 1.6 parts by weight of trimethylolpropane, put them into a reactor, heat them to 175° C., start stirring, introduce nitrogen, and prepolymerize for about 2 hours; heat them by 20° C. every 2 hours to 225° C., and perform ester exchange for 2 hours; add 0.008 parts by weight of tetrabutyl titanate, turn off nitrogen, reduce pressure, take samples and analyze them every hour, and when the acid value is ≤1 mg KOH / g and the hydroxyl value reaches about 41 mg KOH / g, cool and discharge to obtain polyester polyol A with a number average molecular weight of about 3000;

[0062] 100 parts by weight of 1,6-hexanediol, 80 parts by weight of 1,6-hexanediol, and 8.9 parts by weight of neopentyl glycol were weighed and put into a reactor, heated to 140° C., stirred, introduced nitrogen, and prepolymerized for about 2 hours; the temperature was increased by 20° C. every 2 hours to 225° C., and transesterification was performed for 2 hours; 0.008 parts by weight of tetrabutyl titanate was added, the nitrogen was turned off, the pressure was reduced, and samples were taken for analysis every hour. When the acid value was ≤1 mg KOH / g and the hydroxyl value reached about 56 mg KOH / g, the temperature was reduced and the material was discharged to obtain a polyester polyol B with a number average molecular weight of about 2000;

[0063] 2) 17 parts by weight of polyester polyol A, 10 parts by weight of polyester diol B, 19 parts by weight of polyester diol C-Jiangsu Huada CMA3566, 4 parts by weight of polycarbonate diol-Ube UBE's UH-200, 2 parts by weight of polyolefin diol-LBH-2000, 2 parts by weight of polyether diol-PPG 1000, 0.1 parts by weight of antioxidant 1010, 6 parts by weight of tackifying resin-polyacrylic resin-BR113, 2 parts by weight of tackifying resin-polyolefin resin-SUNVISTA666, 2 parts by weight of tackifying resin-EVA resin-40W, and 25 parts by weight of calcium carbonate are put into a reaction device, heated to 160° C., stirred and mixed evenly, cooled to 120° C., vacuum-dehydrated to a moisture content of less than 0.03%;

[0064] 3) Then the temperature was lowered to 90°C, 0.5 parts by weight of p-hydroxyphenylethanol and 0.01 parts by weight of phosphoric acid were added for vacuum dehydration, and then 9 parts by weight of MDI 50 (purchased from Wanhua Chemical) were added, and the reaction temperature was controlled at 90°C for 2 hours. Finally, vacuum was drawn at 120°C until there were no bubbles in the system, and the polyurethane hot melt adhesive was obtained.

[0065] The prepared polyurethane hot melt adhesive was used for edge banding of multilayer board by edge banding machine Hefei Jindiao ZSF-60DL. The edge banding strip was made of PVC material and the ambient temperature was 36°C. After edge banding, it was put into the curing room for curing. At the same time, the peel strength of the edge banding was tested after leaving the machine, 15 minutes, 30 minutes, 24 hours, 48 ​​hours, and 72 hours. The peel strength data are shown in Table 1.

[0066] Example 2

[0067] This example provides a polyurethane hot melt adhesive and a preparation method thereof, and the preparation method of the polyurethane hot melt adhesive comprises the following steps:

[0068] 1) Weigh 5 parts by weight of 1,6-hexanediol, 95 parts by weight of isophthalic acid, 13.6 parts by weight of 1,6-hexanediol, 55 parts by weight of neopentyl glycol, and 1.6 parts by weight of trimethylolpropane, put them into a reactor, heat them to 175° C., start stirring, introduce nitrogen, and prepolymerize for about 2 hours; heat them by 20° C. every 2 hours to 225° C., and perform transesterification for 2 hours; add 0.008 parts by weight of tetrabutyl titanate, turn off nitrogen, reduce pressure, take samples and analyze them every hour, and when the acid value is ≤1 mg KOH / g and the hydroxyl value reaches about 41 mg KOH / g, cool and discharge to obtain polyester polyol A with a number average molecular weight of about 3000;

[0069] 100 parts by weight of 1,6-hexanediol, 80 parts by weight of 1,6-hexanediol, and 8.9 parts by weight of neopentyl glycol were weighed and put into a reactor, heated to 140° C., stirred, introduced nitrogen, and prepolymerized for about 2 hours; the temperature was increased by 20° C. every 2 hours to 225° C., and transesterification was performed for 2 hours; 0.008 parts by weight of tetrabutyl titanate was added, the nitrogen was turned off, the pressure was reduced, and samples were taken for analysis every hour. When the acid value was ≤1 mg KOH / g and the hydroxyl value reached about 56 mg KOH / g, the temperature was reduced and the material was discharged to obtain a polyester polyol B with a number average molecular weight of about 2000;

[0070] 2) 17 parts by weight of polyester polyol A, 10 parts by weight of polyester diol B, 19 parts by weight of polyester diol C-Jiangsu Huada CMA 3566, 4 parts by weight of polycarbonate diol-Ube UBE's UH-200, 2 parts by weight of polyolefin diol-LBH-2000, 2 parts by weight of polyether diol-PPG 1000, 0.1 parts by weight of antioxidant 1010, 6 parts by weight of tackifying resin-polyacrylic acid resin-BR113, 2 parts by weight of tackifying resin-polyolefin resin-SUNVISTA 666, 2 parts by weight of tackifying resin-EVA resin-40W, and 25 parts by weight of calcium carbonate are put into a reaction device, heated to 160° C., stirred and mixed evenly, cooled to 120° C., vacuum-dehydrated to a moisture content of less than 0.03%;

[0071] 3) Then the temperature was lowered to 90°C, 0.5 parts by weight of p-hydroxyphenylethanol and 0.01 parts by weight of phosphoric acid were added for vacuum dehydration, and then 9 parts by weight of MDI 50 (purchased from Wanhua Chemical) were added, and the reaction temperature was controlled at 90°C for 2 hours. Finally, vacuum was drawn at 120°C until there were no bubbles in the system, and the polyurethane hot melt adhesive was obtained.

[0072] The prepared polyurethane hot melt adhesive was used for edge banding of multilayer board by edge banding machine Hefei Jindiao ZSF-60DL. The edge banding strip was made of PVC material and the ambient temperature was 36°C. After edge banding, it was put into the curing room for curing. At the same time, the peel strength of the edge banding was tested after leaving the machine, 15 minutes, 30 minutes, 24 hours, 48 ​​hours, and 72 hours. The peel strength data are shown in Table 1.

[0073] Example 3

[0074] This example provides a polyurethane hot melt adhesive and a preparation method thereof, and the preparation method of the polyurethane hot melt adhesive comprises the following steps:

[0075] 1) Weigh 5 parts by weight of 1,6-hexanediol, 5 parts by weight of phthalic anhydride, 90 parts by weight of isophthalic acid, 6.8 parts by weight of 1,6-hexanediol, 61 parts by weight of neopentyl glycol, and 1.6 parts by weight of trimethylolpropane, put them into a reactor, heat them to 175° C., start stirring, introduce nitrogen, and prepolymerize for about 2 hours; heat them by 20° C. every 2 hours to 225° C., and perform ester exchange for 2 hours; add 0.008 parts by weight of tetrabutyl titanate, turn off nitrogen, reduce pressure, take samples and analyze them every hour, and when the acid value is ≤1 mg KOH / g and the hydroxyl value reaches about 41 mg KOH / g, cool and discharge to obtain polyester polyol A with a number average molecular weight of about 3000;

[0076] 100 parts by weight of 1,6-hexanediol, 80 parts by weight of 1,6-hexanediol, and 8.9 parts by weight of neopentyl glycol were weighed and put into a reactor, heated to 140° C., stirred, introduced nitrogen, and prepolymerized for about 2 hours; the temperature was increased by 20° C. every 2 hours to 225° C., and transesterification was performed for 2 hours; 0.008 parts by weight of tetrabutyl titanate was added, the nitrogen was turned off, the pressure was reduced, and samples were taken for analysis every hour. When the acid value was ≤1 mg KOH / g and the hydroxyl value reached about 56 mg KOH / g, the temperature was reduced and the material was discharged to obtain a polyester polyol B with a number average molecular weight of about 2000;

[0077] 2) 17 parts by weight of polyester polyol A, 10 parts by weight of polyester diol B, 19 parts by weight of polyester diol C-Jiangsu Huada CMA 3566, 4 parts by weight of polycarbonate diol-Ube UBE's UH-200, 2 parts by weight of polyolefin diol-LBH-2000, 2 parts by weight of polyether diol-PPG 1000, 0.1 parts by weight of antioxidant 1010, 6 parts by weight of tackifying resin-polyacrylic acid resin-BR113, 2 parts by weight of tackifying resin-polyolefin resin-SUNVISTA 666, 2 parts by weight of tackifying resin-EVA resin-40W, and 25 parts by weight of calcium carbonate are put into a reaction device, heated to 160° C., stirred and mixed evenly, cooled to 120° C., vacuum-dehydrated to a moisture content of less than 0.03%;

[0078] 3) Then cool to 90°C, add 0.5 parts by weight of p-hydroxyphenylethanol and 0.01 parts by weight of phosphoric acid for vacuum dehydration, then add 9 parts by weight of MDI 50 (purchased from Wanhua Chemical), and control the reaction temperature to react at 90°C for 2h. Finally, evacuate the system at 120°C until there are no bubbles, and discharge the polyurethane hot melt adhesive. The prepared polyurethane hot melt adhesive is used for edge banding of multilayer board materials through the edge banding machine equipment Hefei Jindiao ZSF-60DL. The edge banding strip is made of PVC material, the ambient temperature is 36°C, and the edge banding is put into the health room for curing after completion. At the same time, the edge banding is tested for peel strength, and the peel strength is tested after the machine is removed, 15min, 30min, 24h, 48h, and 72h respectively. The peel strength data are shown in Table 1.

[0079] Example 4

[0080] This example provides a polyurethane hot melt adhesive and a preparation method thereof, and the preparation method of the polyurethane hot melt adhesive comprises the following steps:

[0081] 1) Weigh 5 parts by weight of 1,6-hexanediol, 5 parts by weight of phthalic anhydride, 90 parts by weight of isophthalic acid, 6.7 parts by weight of 1,6-hexanediol, 60.5 parts by weight of neopentyl glycol, and 2.1 parts by weight of trimethylolpropane, put them into a reactor, heat them to 175° C., start stirring, introduce nitrogen, and prepolymerize for about 2 hours; heat them by 20° C. every 2 hours to 225° C., and perform ester exchange for 2 hours; add 0.008 parts by weight of tetrabutyl titanate, turn off nitrogen, reduce pressure, take samples and analyze them every hour, and when the acid value is ≤1 mg KOH / g and the hydroxyl value reaches about 41 mg KOH / g, cool and discharge to obtain polyester polyol A with a number average molecular weight of about 3000;

[0082] 100 parts by weight of 1,6-hexanediol, 80 parts by weight of 1,6-hexanediol, and 8.9 parts by weight of neopentyl glycol were weighed and put into a reactor, heated to 140° C., stirred, introduced nitrogen, and prepolymerized for about 2 hours; the temperature was increased by 20° C. every 2 hours to 225° C., and transesterification was performed for 2 hours; 0.008 parts by weight of tetrabutyl titanate was added, the nitrogen was turned off, the pressure was reduced, and samples were taken for analysis every hour. When the acid value was ≤1 mg KOH / g and the hydroxyl value reached about 56 mg KOH / g, the temperature was reduced and the material was discharged to obtain a polyester polyol B with a number average molecular weight of about 2000;

[0083] 2) 17 parts by weight of polyester polyol A, 10 parts by weight of polyester diol B, 19 parts by weight of polyester diol C-Jiangsu Huada CMA 3566, 4 parts by weight of polycarbonate diol-Ube UBE's UH-200, 2 parts by weight of polyolefin diol-LBH-2000, 2 parts by weight of polyether diol-PPG 1000, 0.1 parts by weight of antioxidant 1010, 6 parts by weight of tackifying resin-polyacrylic acid resin-BR113, 2 parts by weight of tackifying resin-polyolefin resin-SUNVISTA 666, 2 parts by weight of tackifying resin-EVA resin-40W, and 25 parts by weight of calcium carbonate are put into a reaction device, heated to 160° C., stirred and mixed evenly, cooled to 120° C., vacuum-dehydrated to a moisture content of less than 0.03%;

[0084] 3) Then the temperature was lowered to 90°C, 0.5 parts by weight of p-hydroxyphenylethanol and 0.01 parts by weight of phosphoric acid were added for vacuum dehydration, and then 9 parts by weight of MDI 50 (purchased from Wanhua Chemical) were added, and the reaction temperature was controlled at 90°C for 2 hours. Finally, vacuum was drawn at 120°C until there were no bubbles in the system, and the polyurethane hot melt adhesive was obtained.

[0085] The prepared polyurethane hot melt adhesive was used for edge banding of multilayer board by edge banding machine Hefei Jindiao ZSF-60DL. The edge banding strip was made of PVC material and the ambient temperature was 36°C. After edge banding, it was put into the curing room for curing. At the same time, the peel strength of the edge banding was tested after leaving the machine, 15 minutes, 30 minutes, 24 hours, 48 ​​hours, and 72 hours. The peel strength data are shown in Table 1.

[0086] Comparative Example 1

[0087] The polyurethane hot melt adhesive and its preparation method provided in this comparative example are basically the same as those in Example 1, except that the polyester polyol A is prepared by reacting adipic acid and neopentyl glycol, and specifically comprises the following steps:

[0088] 1) Weigh 100 parts by weight of 1,6-hexanediol and 76 parts by weight of neopentyl glycol, put them into a reactor, heat to 145° C., start stirring, introduce nitrogen, and prepolymerize for about 2 hours; heat by 20° C. every 2 hours, heat to 225° C., and perform ester exchange for 2 hours; add 0.008 parts by weight of tetrabutyl titanate, turn off nitrogen, reduce pressure, take samples and analyze every hour, and when the acid value is ≤1 mg KOH / g and the hydroxyl value reaches about 37 mg KOH / g, cool and discharge to obtain polyester polyol A with a number average molecular weight of about 3000;

[0089] 100 parts by weight of 1,6-hexanediol, 80 parts by weight of 1,6-hexanediol, and 8.9 parts by weight of neopentyl glycol were weighed and put into a reactor, heated to 140° C., stirred, introduced nitrogen, and prepolymerized for about 2 hours; the temperature was increased by 20° C. every 2 hours to 225° C., and transesterification was performed for 2 hours; 0.008 parts by weight of tetrabutyl titanate was added, the nitrogen was turned off, the pressure was reduced, and samples were taken for analysis every hour. When the acid value was ≤1 mg KOH / g and the hydroxyl value reached about 56 mg KOH / g, the temperature was reduced and the material was discharged to obtain a polyester polyol B with a number average molecular weight of about 2000;

[0090] 2) 17 parts by weight of polyester polyol A, 10 parts by weight of polyester polyol B, 19 parts by weight of CMA 3566, 4 parts by weight of UH-200, 2 parts by weight of LBH-2000, 2 parts by weight of PPG 1000, 0.1 parts by weight of antioxidant 1010, 6 parts by weight of BR113, 3 parts by weight of SUNVISTA 666, 3 parts by weight of 40W, and 25 parts by weight of calcium carbonate were weighed and put into a reaction device, the temperature was raised to 160° C., stirring was started to mix evenly, the temperature was lowered to 120° C., vacuum dehydration was performed until the moisture content of the material was less than 0.03%;

[0091] 3) Then the temperature was lowered to 90°C, 0.5 parts by weight of p-hydroxyphenylethanol and 0.01 parts by weight of phosphoric acid were added for vacuum dehydration, and then 9 parts by weight of MDI 50 (purchased from Wanhua Chemical) were added, and the reaction temperature was controlled at 90°C for 2 hours. Finally, vacuum was drawn at 120°C until there were no bubbles in the system, and the polyurethane hot melt adhesive was obtained.

[0092] The prepared polyurethane hot melt adhesive was used for edge banding of multilayer board by edge banding machine Hefei Jindiao ZSF-60DL. The edge banding strip was made of PVC material and the ambient temperature was 36°C. After edge banding, it was put into the curing room for curing. At the same time, the peel strength of the edge banding was tested after leaving the machine, 15 minutes, 30 minutes, 24 hours, 48 ​​hours, and 72 hours. The peel strength data are shown in Table 1.

[0093] Comparative Example 2

[0094] The polyurethane hot melt adhesive and its preparation method provided in this comparative example are basically the same as those in Example 1, except that the polyester polyol A is prepared by reacting phthalic anhydride and neopentyl glycol, and specifically comprises the following steps:

[0095] 1) Weigh 100 parts by weight of phthalic anhydride and 75.5 parts by weight of neopentyl glycol, put them into a reactor, heat to 145° C., start stirring, introduce nitrogen, and prepolymerize for about 2 hours; heat by 20° C. every 2 hours until the temperature reaches 225° C., and transesterify for 2 hours; add 0.008 parts by weight of tetrabutyl titanate, turn off nitrogen, reduce pressure, take samples and analyze every hour, and when the acid value is ≤1 mg KOH / g and the hydroxyl value reaches about 37 mg KOH / g, cool and discharge to obtain polyester polyol A with a number average molecular weight of about 3000;

[0096] 100 parts by weight of 1,6-hexanediol, 80 parts by weight of 1,6-hexanediol, and 8.9 parts by weight of neopentyl glycol were weighed and put into a reactor, heated to 140° C., stirred, introduced nitrogen, and prepolymerized for about 2 hours; the temperature was increased by 20° C. every 2 hours to 225° C., and transesterification was performed for 2 hours; 0.008 parts by weight of tetrabutyl titanate was added, the nitrogen was turned off, the pressure was reduced, and samples were taken for analysis every hour. When the acid value was ≤1 mg KOH / g and the hydroxyl value reached about 56 mg KOH / g, the temperature was reduced and the material was discharged to obtain a polyester polyol B with a number average molecular weight of about 2000;

[0097] 2) 17 parts by weight of polyester polyol A, 10 parts by weight of polyester polyol B, 19 parts by weight of CMA3566, 4 parts by weight of UH-200, 2 parts by weight of LBH-2000, 2 parts by weight of PPG 1000, 0.1 parts by weight of antioxidant 1010, 6 parts by weight of BR113, 3 parts by weight of SUNVISTA 666, 3 parts by weight of 40W, and 25 parts by weight of calcium carbonate were weighed and put into a reaction device, heated to 160° C., stirred and mixed evenly, cooled to 120° C., vacuumed and dehydrated to a moisture content of less than 0.03%;

[0098] 3) Then the temperature was lowered to 90°C, 0.5 parts by weight of p-hydroxyphenylethanol and 0.01 parts by weight of phosphoric acid were added for vacuum dehydration, and then 9 parts by weight of MDI 50 (purchased from Wanhua Chemical) were added, and the reaction temperature was controlled at 90°C for 2 hours. Finally, vacuum was drawn at 120°C until there were no bubbles in the system, and the polyurethane hot melt adhesive was obtained.

[0099] The prepared polyurethane hot melt adhesive was used for edge banding of multilayer board by edge banding machine Hefei Jindiao ZSF-60DL. The edge banding strip was made of PVC material and the ambient temperature was 36°C. After edge banding, it was put into the curing room for curing. At the same time, the peel strength of the edge banding was tested after leaving the machine, 15 minutes, 30 minutes, 24 hours, 48 ​​hours, and 72 hours. The peel strength data are shown in Table 1.

[0100] Comparative Example 3

[0101] The polyurethane hot melt adhesive and the preparation method thereof provided in this embodiment are basically the same as those in Example 1, except that: p-hydroxyphenylethanol is not added to the raw materials;

[0102] The preparation method comprises the following steps:

[0103] 1) Weigh 5 parts by weight of 1,6-hexanediol, 95 parts by weight of isophthalic acid, 6.8 parts by weight of 1,6-hexanediol, 61 parts by weight of neopentyl glycol, and 1.6 parts by weight of trimethylolpropane, put them into a reactor, heat them to 175° C., start stirring, introduce nitrogen, and prepolymerize for about 2 hours; heat them by 20° C. every 2 hours to 225° C., and perform ester exchange for 2 hours; add 0.008 parts by weight of tetrabutyl titanate, turn off nitrogen, reduce pressure, take samples and analyze them every hour, and when the acid value is ≤1 mg KOH / g and the hydroxyl value reaches about 41 mg KOH / g, cool and discharge to obtain polyester polyol A with a number average molecular weight of about 3000;

[0104] 100 parts by weight of 1,6-hexanediol, 80 parts by weight of 1,6-hexanediol, and 8.9 parts by weight of neopentyl glycol were weighed and put into a reactor, heated to 140° C., stirred, introduced nitrogen, and prepolymerized for about 2 hours; the temperature was increased by 20° C. every 2 hours to 225° C., and transesterification was performed for 2 hours; 0.008 parts by weight of tetrabutyl titanate was added, the nitrogen was turned off, the pressure was reduced, and samples were taken for analysis every hour. When the acid value was ≤1 mg KOH / g and the hydroxyl value reached about 56 mg KOH / g, the temperature was reduced and the material was discharged to obtain a polyester polyol B with a number average molecular weight of about 2000;

[0105] 2) 17 parts by weight of polyester polyol A, 10 parts by weight of polyester polyol B, 19 parts by weight of CMA 3566, 4 parts by weight of UH-200, 2 parts by weight of LBH-2000, 2 parts by weight of PPG 1000, 0.1 parts by weight of antioxidant 1010, 6 parts by weight of BR113, 2 parts by weight of SUNVISTA 666, 2 parts by weight of 40W, and 25 parts by weight of calcium carbonate were weighed and put into a reaction device, heated to 160° C., stirred and mixed evenly, cooled to 120° C., vacuum-dehydrated to a moisture content of less than 0.03%;

[0106] 3) Then the temperature was lowered to 90°C, 0.01 parts by weight of phosphoric acid was added for vacuum dehydration, and then 9 parts by weight of MDI 50 (purchased from Wanhua Chemical) was added, and the reaction temperature was controlled at 90°C for 2 hours. Finally, vacuum was drawn at 120°C until there were no bubbles in the system, and the polyurethane hot melt adhesive was obtained.

[0107] The prepared polyurethane hot melt adhesive was used for edge banding of multilayer board by edge banding machine Hefei Jindiao ZSF-60DL. The edge banding strip was made of PVC material and the ambient temperature was 36°C. After edge banding, it was put into the curing room for curing. At the same time, the peel strength of the edge banding was tested after leaving the machine, 15 minutes, 30 minutes, 24 hours, 48 ​​hours, and 72 hours. The peel strength data are shown in Table 1.

[0108] Comparative Example 4

[0109] The polyurethane hot melt adhesive and the preparation method thereof provided in this embodiment are basically the same as those in Example 1, except that: 1) 95 parts by weight of 1,6-hexanediol, 5 parts by weight of isophthalic acid, without adding trimethylolpropane, and 8.4 parts by weight of 1,6-hexanediol are weighed;

[0110] 2) Without adding polyester diol B, polycarbonate diol-Ube UH-200, polyolefin diol-LBH-2000, polyether diol-PPG 1000;

[0111] Adjust polyester polyol A to 35 parts by weight;

[0112] The preparation method comprises the following steps:

[0113] 1) Weigh 95 parts by weight of 1,6-hexanediol, 5 parts by weight of isophthalic acid, 8.4 parts by weight of 1,6-hexanediol, and 61 parts by weight of neopentyl glycol, put them into a reactor, heat them to 175° C., start stirring, introduce nitrogen, and prepolymerize for about 2 hours; heat them by 20° C. every 2 hours until they reach 220° C., and perform ester exchange for 2 hours; add 0.008 parts by weight of tetrabutyl titanate, turn off nitrogen, decompress, take samples and analyze them every hour, and when the acid value is ≤1 mg KOH / g and the hydroxyl value is ≤41 mg KOH / g, cool and discharge to obtain polyester polyol A with a number average molecular weight of about 3000;

[0114] 2) 35 parts by weight of polyester polyol A, 19 parts by weight of polyester diol C-Jiangsu Huada CMA 3566, 0.1 parts by weight of antioxidant 1010, 6 parts by weight of tackifying resin-polyacrylic acid resin-BR113, 2 parts by weight of tackifying resin-polyolefin resin-SUNVISTA 666, 2 parts by weight of tackifying resin-EVA resin-40W, and 25 parts by weight of calcium carbonate were put into a reaction device, heated to 160° C., stirred and mixed evenly, cooled to 120° C., vacuumed and dehydrated to a moisture content of less than 0.03%;

[0115] 3) Then the temperature was lowered to 90°C, 0.5 parts by weight of p-hydroxyphenylethanol and 0.01 parts by weight of phosphoric acid were added for vacuum dehydration, and then 9 parts by weight of MDI 50 (purchased from Wanhua Chemical) were added, and the reaction temperature was controlled at 90°C for 2 hours. Finally, vacuum was drawn at 120°C until there were no bubbles in the system, and the polyurethane hot melt adhesive was obtained.

[0116] The prepared polyurethane hot melt adhesive was used for edge banding of multilayer board by edge banding machine Hefei Jindiao ZSF-60DL. The edge banding strip was made of PVC material and the ambient temperature was 36°C. After edge banding, it was put into the curing room for curing. At the same time, the peel strength of the edge banding was tested after the machine was removed, 15 minutes, 30 minutes, 24 hours, 48 ​​hours, and 72 hours later (the test standard is: T / SHPTA046-2023 Reactive polyurethane hot melt adhesive for woodworking edge banding). The peel strength data are shown in Table 1.

[0117] Table 1 Peel strength values ​​at different time periods after edge sealing

[0118] After getting off the plane 15min 30min 24h 48h 72h Example 1 78N 120N 148N 175N 190N 195N Example 2 80N 118N 135N 176N 187N 190N Example 3 75N 118N 140N 176N 188N 192N Example 4 73N 124N 151N 177N 190N 197N Comparative Example 1 60N 85N 105N 121N 140N 146N Comparative Example 2 70N 101N 124N 143N 161N 168N Comparative Example 3 69N 110N 126N 160N 176N 181N Comparative Example 4 55N 76N 95N 110N 119N 121N

[0119] In the above test, the initial peel strength of Examples 1-4 is high after leaving the machine, the peel strength increases significantly within 24 hours, and the peel strength gradually stabilizes after 2 days. The initial peel strength of Comparative Example 1 is low after leaving the machine, the peel strength increases slowly within 24 hours, and the final peel strength is not high. The initial peel strength of Comparative Example 2 is relatively high after leaving the machine, but the peel strength increases slowly within 24 hours, and the peel strength is also lower than that of Example 1. The peel strength of Comparative Example 3 in each time period is lower than that of Example 1, and the peel strength increases slowly. The initial peel strength of Comparative Example 4 is low after leaving the machine, the peel strength increases slowly within 24 hours, and the final peel strength is not high.

[0120] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0121] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

Claims

1. A polyurethane hot melt adhesive, characterized in that: The raw materials of the polyurethane hot melt adhesive include: 1) polyols, wherein the polyols include polyester polyols, polycarbonate diols, polyolefin diols and polyether diols; the polyester polyols account for more than 70% of the polyols in terms of mass percentage; The polyester polyol comprises polyester polyol A, polyester diol B and polyester diol C; The polyester polyol A has a branched structure, and the raw materials of the polyester polyol A include polyacid A and polyol A, wherein the polyacid A is composed of isophthalic acid and adipic acid and / or phthalic anhydride, and the polyol A is composed of hexanediol, neopentyl glycol and trimethylolpropane; The polyester diol B is prepared by reacting an alkyl diol and an alkyl diacid, and the polyester diol C is a crystalline polyester diol; 2) Polyisocyanate; 3) Compound represented by formula (I) R is C 1-6 alkyl.

2. The polyurethane hot melt adhesive according to claim 1, characterized in that: The feed mass ratio of the polyester polyol, the polycarbonate diol, the polyolefin diol and the polyether diol is 37-70:3-5:2-4:1.5-5; and / or the feed mass ratio of the polyester polyol A, the polyester diol B and the polyester diol C is 12-25:10-15:15-30.

3. The polyurethane hot melt adhesive according to claim 1, characterized in that: The hydroxyl value of the polyester polyol A is 32-64 mg KOH / g; and / or, the hydroxyl value of the polyester diol B is 28-58 mg KOH / g; and / or, the hydroxyl value of the polyester diol C is 28-56 mg KOH / g; and / or, the number average molecular weight of the polyester polyol A, the number average molecular weight of the polyester diol B and the number average molecular weight of the polyester diol C are 2000-4000 respectively.

4. The polyurethane hot melt adhesive according to claim 1, characterized in that: The polyester polyol A is prepared by reacting the polyacid A and the polyol A. In terms of weight, the raw materials of the polyester polyol A include: 100 parts of polyacid A and 66-75 parts of polyol A; and / or, In the polyacid A, the molar ratio of the isophthalic acid to the adipic acid and / or phthalic anhydride is 1:0.05-0.3; and / or, In the polyol A, the molar ratio of the hexylene glycol, the neopentyl glycol and the trimethylolpropane is 1:4-11:0.05-0.

3.

5. The polyurethane hot melt adhesive according to claim 1, characterized in that: The raw materials of the polyester diol B include polyacid B and polyol B, the polyacid B includes adipic acid, and the polyol B includes 1,4-butanediol and / or 1,6-hexanediol and neopentyl glycol and / or 2-methylpropanediol; and / or, The raw materials of the polyester diol C include polyacid C and polyol C, wherein the polyacid C is a combination of one or more selected from adipic acid, sebacic acid, and dodecanedioic acid, and the polyol C is a combination of one or more selected from ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and dodecanediol.

6. The polyurethane hot melt adhesive according to claim 1, characterized in that: R is methyl, ethyl or propyl; and / or, R is substituted at the para position; and / or, in terms of mass percentage, the mass ratio of the compound represented by formula (I) to the polyol is 0.0035-0.035:1, further 0.005-0.025:1, and further 0.005-0.015:

1.

7. The polyurethane hot melt adhesive according to claim 1, characterized in that: The number average molecular weight of the polycarbonate diol is 1000-3000; and / or the polyolefin diol is a combination of one or more selected from polybutadiene diol, terminal hydroxyl polybutadiene-acrylonitrile, and terminal hydroxyl hydrogenated polybutadiene; and / or the number average molecular weight of the polyolefin diol is 1800-3000; and / or the polyether diol is polyoxypropylene diol or a combination thereof with polyoxyethylene diol; and / or the number average molecular weight of the polyether diol is 400-2000.

8. The polyurethane hot melt adhesive according to claim 1, characterized in that: The raw material of the polyurethane hot melt adhesive further comprises a combination of one or more of an antioxidant, an inhibitor, a tackifying resin, and a filler; Furthermore, the raw materials of the polyurethane hot melt adhesive include the following components in parts by weight:

9. A method for preparing the polyurethane hot melt adhesive according to any one of claims 1 to 8, characterized in that: The preparation method comprises: The polyol, antioxidant, tackifying resin and filler are uniformly mixed at 140-170° C., cooled to 100-140° C. for dehydration to a moisture content of less than 0.03%, then cooled to 90-110° C., the compound represented by formula (I) and the polymerization inhibitor are added for vacuum dehydration, and then polyisocyanate is added for reaction and degassing to obtain the polyurethane hot melt adhesive.

10. Use of the polyurethane hot melt adhesive according to any one of claims 1 to 8 in edge sealing of panels.

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