Preparation method of environment-friendly low-VOC (volatile organic compound) polyurethane adhesive

Abstract

The invention discloses a preparation method of an environment-friendly low-VOC (volatile organic compound) polyurethane adhesive, and relates to the technical field of low-VOC polyurethane adhesives, and the environment-friendly low-VOC polyurethane adhesive is prepared from the following raw materials in parts by weight: 40-60 parts of polyol, 20-40 parts of polyisocyanate, 5-15 parts of a chain extender, 0.1-1 part of a catalyst, 1-5 parts of an auxiliary agent and 10-30 parts of a low-volatile solvent. According to the preparation method of the environment-friendly low-VOC polyurethane adhesive, low-volatile solvents such as butyl acetate and propylene glycol methyl ether acetate are selected, and the preparation process is optimized, so that the content of VOC in the adhesive is greatly reduced, the pollution to the atmospheric environment is remarkably reduced, and the environment-friendly low-VOC polyurethane adhesive is prepared. The probability of occurrence of environmental problems such as photochemical smog is reduced, the health of a user is practically guaranteed, the harm that VOC stimulates the respiratory tract and causes anaphylactic reaction is avoided, and the current concepts of environmental protection and health are fully met.

Description

Technical Field

[0001] The present invention relates to the field of low-VOC polyurethane adhesives, and particularly to a preparation method of an environment-friendly low-VOC polyurethane adhesive. Background Art

[0002] Polyurethane adhesives have been extremely widely used in many fields such as construction, automobile manufacturing, packaging, electronic appliances, etc. due to their excellent adhesive properties, good chemical resistance, and outstanding flexibility. For example, in automobile manufacturing, polyurethane adhesives are used for bonding body structural parts, which can effectively improve the strength and safety of the vehicle body; in the packaging field, they can be used for bonding various packaging materials to ensure the sealing and stability of the packaging.

[0003] However, traditional polyurethane adhesives will release a large amount of volatile organic compounds (VOCs) during actual use. These VOCs not only cause serious pollution to the surrounding environment and exacerbate the deterioration of the atmospheric environment, such as forming photochemical smog, etc., but also pose many hazards to human health. For example, VOCs can irritate the human respiratory tract, causing discomfort symptoms such as coughing and asthma, and long-term exposure may also lead to allergic reactions and even induce more serious diseases.

[0004] Currently, in order to reduce the content of VOCs in polyurethane adhesives, usually low-volatile solvents are used, the formula is optimized, and the preparation process is improved. Although these methods can reduce the emission of VOCs to a certain extent, there are still obvious limitations. For example, when using low-volatile solvents, the solubility and fluidity of the adhesive may change, thereby affecting its coating performance in actual applications; during the process of optimizing the formula, the adhesive strength may decrease due to the adjustment of certain components, unable to meet the requirements of specific application scenarios; although improving the preparation process can control the generation of VOCs to a certain extent, it often increases the production cost and may also have problems such as a slower curing speed, affecting production efficiency. To solve the above problems, we propose a preparation method of an environment-friendly low-VOC polyurethane adhesive. Summary of the Invention

[0005] The main purpose of the present invention is to provide a preparation method of an environment-friendly low-VOC polyurethane adhesive, which can effectively solve the problems in the background art.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] An environmentally friendly low-VOC polyurethane adhesive, the components and contents of the raw materials used for the environmentally friendly low-VOC polyurethane adhesive include: 40-60 parts of polyol, 20-40 parts of polyisocyanate, 5-15 parts of chain extender, 0.1-1 part of catalyst, 1-5 parts of auxiliary agent, and 10-30 parts of low-volatile solvent.

[0008] Preferably, the polyol is one or a combination of polyether polyol, polyester polyol or polycarbonate polyol.

[0009] Preferably, the polyisocyanate is one or a combination of toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.

[0010] Preferably, the chain extender is one or a combination of ethylenediamine, diethylenetriamine, and 1,4-butanediol.

[0011] Preferably, the catalyst is one or a combination of dibutyltin dilaurate and stannous octoate.

[0012] Preferably, the auxiliary agent is one or a combination of antioxidant 1010, ultraviolet absorber UV-531, and silicone leveling agent.

[0013] Preferably, the low-volatile solvent is one or a combination of butyl acetate and propylene glycol methyl ether acetate.

[0014] The present invention also provides a preparation method of a high-blocking sheet-type expansion adhesive, which specifically includes the following steps:

[0015] S1, adding polyol into a reaction kettle, and carrying out vacuum dehydration at 80-100 °C for 1-2 hours to remove the moisture and low-boiling impurities therein;

[0016] S2, adding a low-volatile solvent to the dehydrated polyol, stirring evenly, and slowly adding polyisocyanate at 40-60 °C, controlling the reaction temperature at 60-80 °C, and reacting for 2-4 hours to obtain a prepolymer;

[0017] S3, adding a chain extender to the prepolymer, and reacting at 60-80 °C for 1-2 hours to further extend the prepolymer;

[0018] S4, adding a catalyst and an auxiliary agent, and stirring and reacting at 40-60 °C for 0.5-1 hour to fully mix and react each component;

[0019] S5, cooling the reacted adhesive to room temperature, filtering to remove impurities, and obtaining an environmentally friendly low-VOC polyurethane adhesive product.

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

[0021] 1. By selecting low-volatility solvents such as butyl acetate and propylene glycol methyl ether acetate and optimizing the preparation process, the present invention greatly reduces the VOC content in the adhesive. This not only significantly reduces the pollution of the atmospheric environment and the occurrence probability of environmental problems such as photochemical smog, but also effectively protects the health of users, avoiding hazards such as VOC irritating the respiratory tract and causing allergic reactions, fully meeting the current environmental protection and health concepts.

[0022] 2. By optimizing the proportion of raw materials such as polyols, polyisocyanates, chain extenders, catalysts, and additives, the present invention ensures low VOC emissions while ensuring excellent bonding performance of the adhesive. Moreover, by adding additives such as antioxidants and ultraviolet absorbers, the antioxidant and ultraviolet resistance of the adhesive are effectively improved, extending its service life. The addition of an organosilicon leveling agent can improve the coating performance, enabling it to be coated more evenly in practical applications. Specific Embodiments

[0023] To make the technical means, creative features, achieved purposes, and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0024] The elements and features described in one embodiment of the present invention can be combined with the elements and features shown in one or more other embodiments. It should be noted that for the purpose of clarity, the representation and description of components or processes that are irrelevant to the present invention and known to those of ordinary skill in the art are omitted in the description.

[0025] The components and contents of the raw materials for the environmentally friendly low-VOC polyurethane adhesive include: 40 - 60 parts of polyol, 20 - 40 parts of polyisocyanate, 5 - 15 parts of chain extender, 0.1 - 1 part of catalyst, 1 - 5 parts of additive, and 10 - 30 parts of low-volatility solvent.

[0026] The polyol is one or a combination of polyether polyol, polyester polyol, or polycarbonate polyol.

[0027] The polyisocyanate is one or a combination of toluene diisocyanate, diphenylmethane diisocyanate, or hexamethylene diisocyanate.

[0028] The chain extender is one or a combination of ethylenediamine, diethylenetriamine, or 1,4-butanediol.

[0029] The catalyst is one or a combination of dibutyltin dilaurate and stannous octoate.

[0030] The additive is one or a combination of antioxidant 1010, ultraviolet absorber UV-531, or organosilicon leveling agent.

[0031] The low-volatility solvent is one or a combination of two of butyl acetate and propylene glycol methyl ether acetate.

[0032] The specific steps of the production method are as follows:

[0033] S1. Add the polyol to the reaction kettle, and carry out vacuum dehydration at 80 - 100 °C for 1 - 2 hours to remove the moisture and low-boiling impurities therein.

[0034] S2. Add the low-volatility solvent to the dehydrated polyol. After stirring evenly, slowly add the polyisocyanate at 40 - 60 °C, control the reaction temperature at 60 - 80 °C, and react for 2 - 4 hours to obtain a prepolymer.

[0035] S3. Add the chain extender to the prepolymer, and react at 60 - 80 °C for 1 - 2 hours to further extend the prepolymer.

[0036] S4. Add the catalyst and the auxiliary agent, and carry out stirring reaction at 40 - 60 °C for 0.5 - 1 hour to fully mix and react each component.

[0037] S5. Cool the reacted adhesive to room temperature, filter to remove impurities, and obtain an environment-friendly low-VOC polyurethane adhesive product.

[0038] Example 1

[0039] Prepare according to the components and contents of specific raw materials: 43 parts of polyol, 25 parts of polyisocyanate, 10 parts of chain extender, 0.5 part of catalyst, 3 parts of auxiliary agent, and 20 parts of low-volatility solvent.

[0040] The specific steps of the production method are as follows:

[0041] S1. Add the polyol to the reaction kettle, and carry out vacuum dehydration at 88 °C for 1.5 hours to remove the moisture and low-boiling impurities therein.

[0042] S2. Add the low-volatility solvent to the dehydrated polyol. After stirring evenly, slowly add the polyisocyanate at 44 °C, control the reaction temperature at 68 °C, and react for 3 hours to obtain a prepolymer.

[0043] S3. Add the chain extender to the prepolymer, and react at 66 °C for 1 hour to further extend the prepolymer.

[0044] S4. Add the catalyst and the auxiliary agent, and carry out stirring reaction at 49 °C for 1 hour to fully mix and react each component.

[0045] S5. Cool the reacted adhesive to room temperature, filter to remove impurities, and obtain an environment-friendly low-VOC polyurethane adhesive product.

[0046] Example 2

[0047] Prepare according to the components and contents of specific raw materials: 55 parts of polyol, 26 parts of polyisocyanate, 8 parts of chain extender, 0.3 part of catalyst, 4 parts of auxiliary agent, and 15 parts of low-volatility solvent.

[0048] The specific steps of the production method are as follows:

[0049] S1. Add the polyol to the reaction kettle, and dehydrate it under vacuum at 95 °C for 1 hour to remove the moisture and low-boiling impurities therein.

[0050] S2. Add the low-volatility solvent to the dehydrated polyol. After stirring evenly, slowly add the polyisocyanate at 51 °C, control the reaction temperature at 77 °C, and react for 2 hours to obtain a prepolymer.

[0051] S3. Add the chain extender to the prepolymer and react at 63 °C for 2 hours to further extend the prepolymer.

[0052] S4. Add the catalyst and the auxiliary agent, and stir and react at 56 °C for 0.6 hour to fully mix and react the components.

[0053] S5. Cool the reacted adhesive to room temperature, filter to remove impurities, and obtain an environment-friendly low-VOC polyurethane adhesive product.

[0054] Example 3

[0055] Prepare according to the components and contents of specific raw materials: 52 parts of polyol, 27 parts of polyisocyanate, 8 parts of chain extender, 0.6 part of catalyst, 3 parts of auxiliary agent, and 24 parts of low-volatility solvent.

[0056] The specific steps of the production method are as follows:

[0057] S1. Add the polyol to the reaction kettle, and dehydrate it under vacuum at 86 °C for 1.8 hours to remove the moisture and low-boiling impurities therein.

[0058] S2. Add the low-volatility solvent to the dehydrated polyol. After stirring evenly, slowly add the polyisocyanate at 52 °C, control the reaction temperature at 74 °C, and react for 2.9 hours to obtain a prepolymer.

[0059] S3. Add the chain extender to the prepolymer and react at 66 °C for 1.9 hours to further extend the prepolymer.

[0060] S4. Add the catalyst and the auxiliary agent, and stir and react at 54 °C for 0.7 hour to fully mix and react the components.

[0061] S5. Cool the reacted adhesive to room temperature, filter to remove impurities, and obtain an environment-friendly low-VOC polyurethane adhesive product.

[0062] Example 4

[0063] Prepare according to the components and contents of specific raw materials: 46 parts of polyol, 31 parts of polyisocyanate, 9 parts of chain extender, 1 part of catalyst, 3 parts of auxiliary agent, and 16 parts of low-volatility solvent.

[0064] The specific steps of the production method are as follows:

[0065] S1. Add the polyol to the reaction kettle, and dehydrate it under vacuum at 92 °C for 1.3 hours to remove the moisture and low-boiling impurities therein.

[0066] S2. Add the low-volatility solvent to the dehydrated polyol. After stirring evenly, slowly add the polyisocyanate at 48 °C, control the reaction temperature at 64 °C, and react for 3.2 hours to obtain a prepolymer.

[0067] S3. Add the chain extender to the prepolymer and react at 78 °C for 1.6 hours to further extend the prepolymer.

[0068] S4. Add the catalyst and auxiliary agent, and stir and react at 45 °C for 0.8 hours to fully mix and react all components.

[0069] S5. Cool the reacted adhesive to room temperature, filter to remove impurities, and obtain an environmentally friendly low-VOC polyurethane adhesive product.

[0070] Example 5

[0071] Prepare according to the components and contents of specific raw materials: 52 parts of polyol, 33 parts of polyisocyanate, 14 parts of chain extender, 0.6 part of catalyst, 4 parts of auxiliary agent, and 22 parts of low-volatility solvent.

[0072] The specific steps of the production method are as follows:

[0073] S1. Add the polyol to the reaction kettle, and dehydrate it under vacuum at 82 °C for 1.6 hours to remove the moisture and low-boiling impurities therein.

[0074] S2. Add the low-volatility solvent to the dehydrated polyol. After stirring evenly, slowly add the polyisocyanate at 45 °C, control the reaction temperature at 69 °C, and react for 3.2 hours to obtain a prepolymer.

[0075] S3. Add the chain extender to the prepolymer and react at 73 °C for 1.6 hours to further extend the prepolymer.

[0076] S4. Add the catalyst and auxiliary agent, and stir and react at 46 °C for 0.6 hours to fully mix and react all components.

[0077] S5. Cool the reacted adhesive to room temperature, filter to remove impurities, and obtain an environmentally friendly low-VOC polyurethane adhesive product.

[0078] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly low-VOC polyurethane adhesive, characterized in that, The components and contents of the raw materials for the environmentally friendly low-VOC polyurethane adhesive include: 40-60 parts of polyol, 20-40 parts of polyisocyanate, 5-15 parts of chain extender, 0.1-1 part of catalyst, 1-5 parts of auxiliary agent, and 10-30 parts of low-volatility solvent.

2. An environmentally friendly low-VOC polyurethane adhesive according to claim 1, characterized in that, The polyol is one or a combination of polyether polyol, polyester polyol, or polycarbonate polyol.

3. An environmentally friendly low-VOC polyurethane adhesive according to claim 1, characterized in that, The polyisocyanate is one or a combination of toluene diisocyanate, diphenylmethane diisocyanate, or hexamethylene diisocyanate.

4. An environmentally friendly low-VOC polyurethane adhesive according to claim 1, characterized in that, The chain extender is one or a combination of ethylenediamine, diethylenetriamine, or 1,4-butanediol.

5. An environmentally friendly low-VOC polyurethane adhesive according to claim 1, characterized in that, The catalyst is one or a combination of dibutyltin dilaurate and stannous octoate.

6. An environmentally friendly low-VOC polyurethane adhesive according to claim 1, characterized in that, The auxiliary agent is one or a combination of antioxidant 1010, ultraviolet absorber UV-531, or silicone leveling agent.

7. An environmentally friendly low-VOC polyurethane adhesive according to claim 1, characterized in that, The low-volatility solvent is one or a combination of butyl acetate and propylene glycol methyl ether acetate.

8. A preparation method of an environmentally friendly low-VOC polyurethane adhesive, according to any one of claims 1-7, an environmentally friendly low-VOC polyurethane adhesive, characterized in that, Specifically, it includes the following steps: S1. Add the polyol to the reaction kettle, and carry out vacuum dehydration at 80-100 °C for 1-2 hours to remove the moisture and low-boiling impurities therein. S2. Add the low-volatility solvent to the dehydrated polyol. After stirring evenly, slowly add the polyisocyanate at 40-60 °C, control the reaction temperature at 60-80 °C, and react for 2-4 hours to obtain a prepolymer. S3. Add the chain extender to the prepolymer and react at 60-80 °C for 1-2 hours to further extend the prepolymer. S4. Add the catalyst and auxiliary agent, and stir and react at 40-60 °C for 0.5-1 hour to fully mix and react all components. S5. Cool the reacted adhesive to room temperature, filter to remove impurities, and obtain an environmentally friendly low-VOC polyurethane adhesive product.