A method for producing two-component and one-component moisture-curing polyurethane prepolymers that are excellent in safety, short-time setting properties, and moisture curing properties, and a manufacturing apparatus.

Abstract

This invention provides a method and apparatus for manufacturing two-component and novel (usable at room temperature) one-component moisture-curing polyurethane prepolymers, achieving both versatility and safety / environmental friendliness, further improvements in product manufacturing technology and performance (quality), energy savings, and improved ease of operation. [Solution] For the two-component and one-component types described above, safety was improved by using safe monodiisocyanates with low vapor pressure. Furthermore, quality was improved by increasing the accuracy of the constant reactivity ratio of the two components. In addition, for the one-component type, a product storage unit was added to the apparatus, enabling continuous production of one-component moisture-curable prepolymers and the economical construction of the apparatus. As a result, this led to the development of a novel room-temperature, one-component, moisture-curable product.

Description

Technical Field

[0001] The present invention relates to a continuous production method and a production apparatus for a two-component moisture-curing polyurethane prepolymer, which are excellent in safety, environmental friendliness, short-time synthesis, energy saving, operability, short-time fixing property (high adhesion to fixing) at room temperature, product reliability, and moisture curability. Furthermore, the present invention relates to a continuous production method, a production apparatus, and a product of a one-component prepolymer obtained using the production apparatus.

Background Art

[0002] The cured product of the current moisture-curing terminal isocyanate prepolymer used in products such as adhesives, sealants, and coatings is particularly well-known in the field of moisture-curing polyurethane reactive hot melt cured products (one-component type; abbreviated as PURHM). Under moisture barrier, the PURHM has easy fluidity under heating and forms instant high adhesion to solidification by cooling at room temperature. However, once it is fixed, through the moisture absorbed from the air and the surface of the adherend during the discharge process, it is converted into a thermosetting type (thermally irreversible) by a crosslinking reaction to give a strong cured body. Thus, it is a material excellent in easy operability by the one-component type, high productivity by instant fixing, and functional and performance aspects by the thermosetting type. Therefore, the product has widely penetrated the market and formed a domain in the industry.

[0003] The current PURHM has the above advantages but also has weaknesses. Its production is a batch method, which requires a long time (≈100 °C, several hours) under heating and consumes a large amount of energy for production. Also, when using the product, a dedicated coating machine is required, and the product is put into a melting tank, heated and remelted for use. Therefore, it is necessary to heat the entire apparatus including the piping and the discharge part, and a large amount of energy is also consumed during use. In contrast, the two-component type of the present technology is more energy-saving, establishes easy operability comparable to the one-component type, and can also make the production apparatus inexpensive and economical.

[0004] The inventors have consistently researched energy-saving PURHM to address the shortcomings of the current one-component method. As a result, in the prior invention (abbreviated as prior invention), focusing on the high-speed reactivity of polyurethane and the reaction without by-products, they discovered a method for stably synthesizing moisture-curing terminal isocyanate prepolyar directly from two raw materials in a short time, within a heated reactor, and using it as a product. This resulted in the invention of a new energy-saving, easy-to-operate, and economical manufacturing method that integrates manufacturing and product use. In the prior invention, a product evaluation method was disclosed in the manufacturing apparatus and system (Patent Document 1). Furthermore, a method for reducing residual monomers (Patent Document 2) was disclosed to improve the safety of the raw material isocyanate. In addition, an improvement to the problem of foaming of cured products during moisture curing was disclosed (Patent Document 3).

[0005] On the other hand, energy-saving, room-temperature two-component reaction-curing types (polyurethane, epoxy, acrylic, silicone, etc.), which are in competition with the present invention, are suitable for obtaining diverse and high-performance physical properties, but generally have the weakness of slow curing speed and lacking high productivity. If a rapid curing type is used, gelation (curing) due to the mixing of the two components in the mixer may occur, potentially clogging the mixer. In current technology, the minimum time required to suppress gelation at room temperature is approximately 2 to 5 minutes. As a countermeasure against this gelation, the inventor disclosed an improvement measure (Patent Document 4) in the previous invention (two-component rapid-curing polyurethane), but issues remained in terms of operability.

[0006] The inventors diligently conducted research to resolve the problems of the current one-component PURHM and the current room-temperature two-component reaction type, while aiming to combine the advantages of both. However, in order to achieve the above combination, there was still room for improvement in this technology (prior invention). The first issue is that the raw material isocyanate requires careful handling due to its safety and environmental impact. Moreover, since the present invention is used under heating, evaluation, improvement, and confirmation of safety were urgent priorities. This involved reviewing the raw materials (especially polyisocyanates (Non-Patent Documents 1-2)) and evaluating them appropriately. Secondly, polyurethane is excellent at rapid reactions and generates a large amount of reaction heat in the process. The goal was to utilize this reaction heat and improve the reactor to further reduce energy consumption. The third objective was to improve upon the two-component apparatus of the present invention, develop a more stable one-component continuous manufacturing apparatus using the same technology, and develop a one-component product that can be used at room temperature. The inventors have considered this matter and have focused on improving this technology.

[0007] The terms and other concepts used in this invention are defined below. Regarding "moisture-curing polyurethane reactive hot melt": The current manufacturing method (product) will be differentiated as a one-component type, while this technology will be a two-component type. • "Continuous manufacturing according to the present invention" includes "intermittent manufacturing associated with on / off manufacturing of products, etc." • When referring to liquid at room temperature, "room temperature" includes a slightly heated state (near room temperature; approximately 35°C or below), taking into account recent global warming. Regarding "high adhesion" and "solidification": There is no strict distinction between the two. "High adhesion" refers to a highly viscous liquid state. Solidification exhibits properties closer to "solidification." Viscosity is higher for solidification than for high adhesion. Regarding "dispensing" and "coating": There is no strict distinction. Coating refers to applying a substance to a substrate after it has been dispensed. • The "prepolymer of the present invention" exhibits thermal fluidity (thermoplasticity) under moisture barrier conditions and at specified heating temperatures, and upon contact with moisture (water), it gels and exhibits a three-dimensional network structure of a crosslinking precursor and a crosslinking material. Regarding "crosslinked material" and "cured material": There is no strict distinction; the cured material in this invention refers to a thermosetting type cured material. • Handling of the vapor pressure values ​​shown in this invention; The vapor pressures dealt with in this invention are in an extremely small range; therefore, special equipment and special techniques are required for measuring the values. The numerical values ​​used were those from authoritative publications and values ​​derived (calculated) from polymer and general chemical theory. Furthermore, the vapor pressures of the resulting prepolymers at 100°C and 50°C were taken from the values ​​obtained from the virtual diagrams shown in Table 1. [Patent Document 1] Patent No. 5044749 [Patent Document 2] Patent No. 5853295 [Patent Document 3] Patent No. 6698981 [Patent Document 4] Patent No. 5422282 [Non-Patent Document 1] Materials from the Japan Urethane Industry Association (Table 7, Appendix 1) [Non-Patent Document 2] Urethane Raw Materials Industry Association MSDS Polymeric MDI; dated February 8, 2023; page 5) [Non-Patent Document 3] Textbook of Polymer Chemistry, by Minoru Imoto and Ryoichi Fujishiro, 1967. [Disclosure of the Invention] [Problems that the invention aims to solve]

[0008] This invention represents a further improvement to the method for producing moisture-curing terminal isocyanate prepolymer compositions, integrating the manufacturing and coating processes of the prior invention. Specifically, it aims to achieve both versatility, safety, and environmental friendliness, further improve the manufacturing technology and performance (quality) of the product, reduce energy consumption, and improve ease of operation. With regard to this technology, by adding new insights to the long-cultivated technology and completing a completely new technology, the aim is to resolve the problems of the conventional technology and provide a method and apparatus for producing two-component and novel (usable at room temperature) one-component moisture-curing polyurethane prepolymers. [Means for solving the problem]

[0009] The inventors of this invention have diligently investigated the above-mentioned problems. By adding new insights and resolving the problems of the prior art, we have been able to provide a novel method and apparatus for manufacturing moisture-curing polyurethane prepolymers.

[0010] In other words, the present invention consists of the following inventions. (1) A method for producing a two-component moisture-curable polyurethane prepolymer using an apparatus that simultaneously manufactures the prepolymer and dispenses / coats it, wherein liquid A is mainly composed of a liquid dily isocyanate having a number average molecular weight (Mn) of 150 to 10,000, a viscosity at 25°C of 5 to 100,000 mPa·s, and a vapor pressure of 1 Pa or less, preferably 10 mPa (10 to the power of minus 2 Pa) or less, and liquid B is mainly composed of a liquid diol having a number average molecular weight (Mn) of 62 to 15,000, and a viscosity at 25°C of 50 to 50,000 mPa·s, and the variation in the reaction ratio of the two liquids is within the range of 95 to 105 (abbreviated as 1 ± 0.05), preferably 1 ± 0.03, with 100 as the base. This is a method for producing a two-component moisture-curable polyurethane prepolymer, characterized by its safety, environmental friendliness, energy efficiency, ease of operation, short-time adhesion at room temperature (high adhesion to adhesion), product reliability, and excellent moisture-curability. The prepolymer obtained by supplying it to a substantially anhydrous reactor that is heated while maintaining the ratio at all times, with an NCO / OH group ratio of 1.3 / 1 to 3.0 / 1, a reaction temperature of 60 to 170°C, and a reaction time of 2 to 120 seconds exhibits fluidity at the heated temperature and high adhesion to adhesion at 25°C. The vapor pressure of the prepolymer (diisocyanate) obtained by discharge from the discharge port at the bottom of the reactor at 50°C is less than or equal to the TWA value (equivalent to vapor pressure; 0.45 mPa).

[0011] (2) A method for producing a moisture-curing polyurethane prepolymer according to claim 1, characterized in that the main component of the polyisocyanate is diisocyanate and the content of diisocyanate (relative to the total amount of polyisocyanate) is 70% by mass or more, and the main component of the polyol is diol and the content of diol (relative to the total amount of polyol) is 70% by mass or more.

[0012] (3) The above heating state is obtained by the reaction heat of the two liquids or by using an external heater, as described in (1) or (2) above. (4) The above reaction time is 2 to 120 seconds, preferably 2 to 60 seconds, more preferably 2 to 30 seconds, and most preferably 1 to 15 seconds, as described in any one of (1) to (3) above. (5) The above high tackiness to adhesion of the prepolymer at 25°C is such that the viscosity is 50,000 to 1,000,000 mPa·s, or the adhesion temperature is 20°C to 50°C. (6) The above short curing time is 2 to 120 seconds, preferably 1 to 30 seconds, and more preferably 1 to 15 seconds, as described in any one of (1) to (5) above.

[0013] (7) A manufacturing apparatus for producing the prepolymer of (1) above, wherein the heater for creating a heated state is a moisture-curing polyurethane prepolymer manufacturing apparatus that can be easily attached to and detached from the reactor. (8) The manufacturing apparatus of (7) comprises two (a) storage containers, a (b) precision quantitative dispensing machine, a (c) an optional switching valve, and a reactor having a supply section and a discharge section, a connection section and connecting piping for connecting (a) to (d), and (e) various sensors and a control section for confirming the reaction product, and is a moisture-curing polyurethane prepolymer manufacturing apparatus having means for confirming the product. (9) The structure of the storage container of (a) above includes a container with a double structure. (10) The switching valve of (a) above is preferably a three-way valve, and the piping configuration allows for substitution with polyol (both liquids or one liquid) to prevent gelation of the generated prepolymer in the reactor during and after the reaction as needed.

[0014] (11) The manufacturing apparatus of (8) above is characterized in that the prepolymer generated in the reactor is directly provided with a product storage container (f) for storing the product from the discharge part of the reactor, and it is the manufacturing apparatus of the moisture-curing type polyurethane prepolymer according to any one of (7) to (10) above. (12) The apparatus of (11) is an apparatus capable of continuously manufacturing a one-component type moisture-curing type polyurethane prepolymer. (13) It is a room-temperature one-component moisture-curing composition that can be used near room temperature and is manufactured by the manufacturing apparatus of (12) above. (14) The composition of (13) is a one-component moisture-curing polyurethane adhesive, coating agent, sealing agent, or molding material, etc.

Advantages of the Invention

[0015] As described above, the present invention has been able to further improve the manufacturing method of the two-component moisture-curing type polyurethane prepolymer that integrates the manufacturing and coating of the previous invention by the present inventor. That is, the present invention has been able to expand the diversity, achieve compatibility with environmental protection, improve manufacturing technology, performance, energy saving, and ease of operation. Moreover, it has led to the development of a continuous manufacturing method and apparatus for a one-component moisture-curing type polyurethane prepolymer that further develops this technology. The present invention is a technology that has never existed before, and for the first time, it has become possible to maintain the advantages of both the conventional technology (current one-component PURHM and current room-temperature two-component reaction-curing type). Also, different performances can be expected for current room-temperature one-component moisture-curing type products of different types. As a result, the present invention is expected to contribute to the industrial world.

Best Mode for Carrying Out the Invention

[0016] · First, the present invention (measures for improving the problems of the previous invention, etc.) is outlined below, and the details are described in the examples. · Improvement in safety and environmental friendliness; Safety and environmental friendliness are the most important issues for users. Regarding polyurethane, there are concerns about the safety of raw material polyisocyanates, especially under heating. In particular, although the present invention is a sealed system, it is carried out in a heating system, so care must be taken regarding the toxicity of isocyanate vapor and attention must be paid to raw material selection. The inventor created a vapor pressure diagram of highly usable isocyanate raw materials by examining authoritative documents such as various isocyanate raw materials (Non-Patent Documents 1 and 2), etc., and based on this, for the legally set vapor pressure that is the subject of the present invention, the present invention was first revealed to be extremely safe, as shown in Example 1 (Table 1). · One-component continuous manufacturing apparatus and product development; It was shown by model tests that it is possible to create products of one-component room-temperature moisture-curing type at room temperature, as shown in Example 2 (Table 2). (3) Promotion of energy conservation (utilization of reaction heat, improvement of heaters, etc.); The reaction heat generated by the two-component high-speed reaction was actively utilized. In particular, it was recognized that a large amount of heat is generated in the MDI system even without a catalyst. The amounts of heat generation were accumulated and utilized in the reactor, and the structures of the entire reactor and the heater are shown in Example 3 (Figure 1) and Example 4 (Figure 2). (4) Also, the summary of the present invention is shown in Example 5 (Table 3).

[0017] 2. The manufacturing method of the present invention will be described. (1) The present invention uses a two-component reaction apparatus in a heated state, and uses room-temperature liquid polyisocyanate and polyol as raw materials to instantaneously synthesize a moisture-curing prepolymer (thermoplastic) and discharge it as it is, and instantaneously high-adhesion ~ solidify it by air cooling. At the time of solidification, moisture and water in the external environment (in the air and the adherend) are absorbed. This moisture is used as a reaction source for cross-linking body formation and is converted into a thermosetting hardened body (three-dimensional network structure). The present invention is a method for manufacturing two-component and one-component moisture-curing prepolymers that are precursors of the hardened body.

[0018] (2) Raw material polyisocyanate (Liquid A) Assuming the isocyanate vapor pressure mentioned earlier is satisfied, any isocyanate that meets the following conditions, whether monomer or prepolymer, can be used. Specifically, liquid 2-3 functional polyisocyanates and low molecular weight terminal NCO prepolymers that are liquid at room temperature are usable. Viscosity is not particularly restricted, and any material that can be accurately dispensed by a precision metering dispenser is usable. Typically, a range of 50,000 to 100,000 mPa·s is convenient for stable dispensing. The above polyisocyanates and terminal NCO prepolymers are usually used in a mixed state, and any system that does not undergo phase separation and has good miscibility can be used. The above polyisocyanates are bifunctional (primarily diisocyanate, 70% or more by mass), and some also contain trifunctional (triisocyanate). The reason for using diisocyanate as the main component is that it is suitable for obtaining the terminal NCO type linear prepolymer (thermoplastic) of the present invention. The diisocyanate component accounts for 70% or more by mass, preferably 80% or more by mass, of the total polyisocyanate components. In other words, an average functional number (Fn) of 2.3 to 1.8, preferably 2.1 to 1.9, is appropriate. The number-average molecular weight (Mn) is suitable in the range of 150 to 10,000, which is suitable for the multi-product manufacturing of the present invention. However, it is not limited to this.

[0019] The reaction rates of the polyisocyanates used are in the order of aromatic > alicyclic > aliphatic. A representative example of aromatic polyisocyanates is MDI, and in a catalyst-free mixture (MDI / polyol; 2 mg equivalent / 1 mg), the temperature rose by 30-50°C in a few seconds. By effectively utilizing this reaction heat, further energy conservation is expected. An example of an alicyclic polyisocyanate is IPDI (isophorone diisocyanate). Prioritizing safety, it is appropriate to use it as a raw material for the low molecular weight, double-ended NCO prepolymers mentioned above. An example of an aliphatic polyisocyanate is HDI (hexamethylene diisocyanate), but HDI has a slow reaction rate and high vapor pressure, making it difficult to use alone. However, like IPDI, it is useful as a raw material if it is prepolymerized and the residue is preserved (see Table 1). This is available as a commercially available product. For this raw material, a high-speed reaction (high exothermic reaction) was confirmed in a high-concentration catalyst addition system. Furthermore, since the present invention emphasizes the effective utilization of reaction heat, an MDI system is suitable. Numerous experiments with MDI systems were conducted in the prior invention (Patent Document 3). From these, a system suitable for the present invention was narrowed down and further confirmed through follow-up experiments.

[0020] Examples of liquid MDI systems useful for safety and energy saving are shown below; (a) MDI (diphenylmethane diisocyanate; Examples include (4,4'MDI, 2,4'MDI, 2,2'MDI isomers or mixtures of isomers), (b) carbodiimide-modified diisocyanates, uretodiimine-modified isocyanates, (c) terminal MDI-containing prepolymers obtained by reacting excess MDI with diols, or (d) blends of the terminal MDI-containing prepolymer and 4,4'MDI monomers. Many of the room-temperature liquid terminal NCO prepolymers of (c) can be easily produced by reacting them with short-chain diols or low-viscosity diols in excess MDI, and these are also useful as raw materials. Many are also available commercially, for example, Coronate MX, Coronate MT, Coronate 1050, Millionate NM, Millionate MR200, etc. (all from Tosoh Corporation). Also, castor oil-modified terminal NCO prepolymers (URIC Examples include N2023 (Ito Oil Co., Ltd.), and several other companies supplying these commercially available products, which can be used individually or in mixtures. The raw materials of the present invention are not limited to these.

[0021] (3) Polyol raw material (Solution B); A polyol that is liquid at room temperature (25°C) is most desirable, and a diol with an average functional number of 2 is preferred, but it may also contain a triol with 3 valent (3 functional) properties. Similar to the diisocyanate mentioned above, it is difficult to obtain a pure product due to impurities during synthesis, side reactions, and moisture absorption during storage. It can be used if the diol component content is 70% by mass or more of the total polyol component. Preferably it is 80% by mass or more. In other words, the average functional number (Fn) is 2.3 to 1.8, preferably 2.1 to 1.9. Also, the average molecular weight (Mn) is appropriate in the range of 62 to 15000. These diol raw materials are selected from diols usually described in urethane chemistry, with main chain structures including polytetramethylene ether systems, polyethylene oxide propylene glycol polyether systems, polyester systems, polycarbonate systems, castor oil modified systems, etc. Polyether diols are useful for their low viscosity, polycarbonate diols for their hydrolysis resistance and strength, and polyester diols for their heat resistance.

[0022] Furthermore, short-chain diols with 3 to 10 carbon layers are also useful as chain extenders. These include triethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, octanediol (2-ethyl-1,3-hexanediol), 2,4-diethyl-1,5-pentanediol, small amounts of trifunctional glycerin, trimethylolpropane, etc., which can be used as long as they do not reduce the heating fluidity of the prepolymer. These diols can be used alone or as mixed diols. However, the diols of the present invention are not limited to these.

[0023] (4) Catalyst; The MDI system of the present invention reacts very rapidly under heating, making instantaneous synthesis (approximately 100°C, 1-30 seconds or less) possible even in a catalyst-free system. The amount of catalyst added is greatly affected by the type of raw material, the amount of raw material used, and the reaction temperature, and as a result, the amount of heat generated also changes significantly. Therefore, to ensure safety (abnormal heat generation), it is best to start the reaction with a small amount of catalyst. However, since the present invention also aims at energy saving, a high amount of catalyst is effective in HDI prepoly systems to take advantage of this high reactivity. The catalysts used are known catalysts that are commonly used in polyurethane chemistry. Examples of such catalysts include: organometallic compounds of tin, iron, titanium, or bismuth, such as dibutyltin dilaurate (DBTDL), dioctyltin dilaurate, tin(II) salts of carboxylic acids, amines, etc., which are suitable catalysts for use in the present invention. The concentration of the catalyst in the composition used is approximately 0.0001 to 1.0% by mass, preferably 0.005 to 0.05% by weight, and more preferably 0.05 to 0.002% by mass. Catalysts described in general polyurethane chemistry are used.

[0024] (5 additives; The present invention benefits from the addition of additives. Stabilizers, adhesion promoters, fillers, tackifiers, pigments, antioxidants, UV absorbers, etc., can be included as desired. In particular, the addition of various inorganic powders and metal powders, from which substantial water has been removed, as fillers reduces the prepolymer concentration in the composition. This reduction in raw material monomers lowers the vapor pressure of the monomers in this invention, resulting in a safer product. Furthermore, it reduces the amount of carbon dioxide that causes foaming, thereby reducing foaming. It is also useful for controlling (mitigating) the large amount of reaction heat during the instantaneous synthesis of the prepolymer. Additionally, it can be expected to adjust the viscosity (adhesion, etc.) of the product. Moreover, it can be expected to improve various physical properties of the cured product, such as strength, heat resistance, weather resistance, water resistance, and chemical resistance. In this invention, improved adhesion is expected. Furthermore, it reduces product cost, resulting in significant economic benefits. Inorganic additives (powder) are available from various manufacturers and can be appropriately selected according to the product of this invention. The amount of inorganic filler added is influenced by the product type, composition, shape, particle size, etc., but is a maximum of 70% by mass or less. Preferably, it is 50% by mass or less. Organic powders, such as wood powder and algae powder, are also useful. However, the present invention is not limited to these.

[0025] (6) Conditions for producing prepolymers Next, we will explain the manufacturing conditions for the prepolymer. Variation in the reaction ratio of the two components; Standard reaction ratio; As a result of considering measures to stabilize and improve the quality of the present invention (two-component type), it is most important to constantly maintain the two raw material components within a certain range and supply them to the reactor to react. As mentioned above, when the standard value of the reaction ratio of the two components is set to 1, the appropriate condition is within the range of 1 ± 0.05, preferably 1 ± 0.03. To keep the variation within this range, the discharge accuracy of commercially available precision quantitative dispensers for two-component reactive adhesives is within 1 ± 0.03, so the problem of this variation can be solved by using or improving these commercially available products. Temperature; The reaction temperature is 60 to 170°C, preferably 70 to 130°C, more preferably 80 to 120°C. At temperatures above 170°C, there is a risk of deterioration of the generated prepolymer and concerns regarding safety (including vapor pressure). Also, at temperatures below 60°C, there is a risk of a decrease in the reaction rate and a decrease in the thermal fluidity of the product. Reaction time; The reaction time is 2 to 120 seconds, preferably 2 to 30 seconds, and more preferably 2 to 15 seconds. The NCO / OH group ratio is 1.3 / 1 to 3.0 / 1, preferably 1.3 / 1 to 2.5 / 1, and more preferably 1.5 / 1 to 2.0 / 1. A ratio of 3 / 1 or higher is undesirable because it results in an excess of unreacted diisocyanate raw materials, which significantly promotes foaming during moisture curing. It may also have negative effects on safety.

[0026] (7) Properties of the resulting prepolymer; The above polyisocyanonetonate (Solution A) and polyol (Solution B) are used and produced under the above conditions. Prepolymer Viscosity; A moisture-curing (terminal NCO group) thermoplastic prepolymer that exhibits fluidity under heating and solidifies instantly upon dispensing and air cooling. The properties of the prepolymer are influenced by the raw material type (molecular weight, skeletal structure), molecular weight (NCO / OH group), etc., and in particular, viscosity behavior (fluidity under heating, and viscosity to adhesion at room temperature) affects various properties. This invention is well-suited for the manufacture of a wide variety of products and diverse applications. The viscosity of the prepolymer alone is suitable in a wide range of 50,000 mPa·s at 25°C and 500 mPa·s or more at 120°C, but is not limited to these ranges. Moisture-curing properties; when the heated fluid is discharged into the environment, it absorbs moisture from the air and the adherend, converting the moisture into a thermo-cured material (three-dimensional network structure) using moisture as a reaction source (amine crosslinking). The moisture crosslinking rate follows the reactivity of the polyisocyanate, showing aromatic > alicyclic > aliphatic. Moisture-curing properties are evaluated by the heat resistance temperature (by constant-rate heating method).

[0027] The manufacturing apparatus of the present invention will be described in the section on examples. 4. Examples; The present invention will be described below with reference to examples. The present invention is not limited to these examples.

[0028] [Table 1]

[0029] Example 1. Evaluation and Improvement of Safety; In order to evaluate the safety of raw materials such as poly-monomery isocyanates, six different product types (six types in the right-hand box) were selected as examples of the isocyanates in Table 1, referring to Non-Patent Documents 1 and 2, and vapor pressure diagrams were created from the values ​​of vapor pressure at 25°C and boiling point (three types) from Non-Patent Document 1. As a result, it was found that the slope of the diagram (vapor pressure (Pa) ~ reciprocal of absolute temperature (1 / T)) remained constant regardless of the type of isocyanate. Applying this slope to the MDI system, a vapor pressure diagram (virtual diagram) was created for monopolymeric MDI with an unknown boiling point (above 300°C). Inhalation toxicity was selected as the safety indicator and estimated from the legally regulated value (monomeric MDI). Since the raw materials used in this invention are carried out in a heating system, it is necessary to select raw materials with low vapor pressure. The permissible concentration for the human body (TWA; average concentration for regular workers, 8 hours a day, 40 hours a week) is specified as 0.05 mg per cubic meter as the vapor pressure at 25°C. Converting this to vapor pressure (calculation) gives 0.45 mPa, which is shown as a thick dotted line in the diagram. The MDI used in this invention (polypolymer: 0.4 mPa, monopolymer: 0.56 mPa) shows a vapor pressure lower than this specified value, indicating that there are no safety issues.

[0030] In this invention, the vapor pressure of the isocyanate at 25°C is limited to 1 Pa or less, preferably 10 mPa (10 to the power of minus 2 Pa) or less. This value exceeds the TWA value and cannot be used alone. However, in actual use systems, it is not used alone, and most of the diisocyanate is consumed in the prepolymer formation reaction with the polyol. In an NCO / OH ratio 2 / 1 system, theoretically 100% is consumed, but up to approximately 10% can be considered unreacted. In addition, dilution and curing by polyols and fillers, and reactions with water can also be considered. Therefore, the decrease in the initial concentration of the isocyanate (abbreviated as low vapor pressure treatment) is significant. Furthermore, the decrease in concentration of the isocyanate prepolymer due to the treatment of residual monomers is also significant. Taking all of the above into consideration, the vapor pressure value of this invention was limited.

[0031] Regarding the reduction in vapor pressure, the inventors estimated that the initial concentration of vapor pressure would be reduced by at least 1 / 20. Based on this, the low vapor pressure treatment and the corresponding diagram shown in Table 1 were created. In this invention, although it is used in a heating system, even in that case, the vapor pressure at 50°C, both pMDI and mMDI, remained within TWA, demonstrating a significant improvement in safety. Furthermore, the effect of prepolymerization was significant; in the figure, the HDI value of approximately 1 Pa in its pure form was shown to be less than 1 / 100 of the pure form after prepolymerization and residual monomer treatment (HDI concentration measurement) (based on analysis values ​​from the manufacturer). As a result, in terms of safety, this invention, although used in a heating system, can be said to be extremely safe. However, since sensitization reactions differ from person to person, measures to improve the working environment, such as wearing protective equipment and installing exhaust systems, are important to ensure greater safety.

[0032] [Table 2]

[0033] Example 2: Development of a room-temperature, one-component, moisture-curing product The inventors, having reviewed the test results of the prior invention (Patent Document 3) and conducted some follow-up tests, conceived an idea for utilizing a large amount of heat generation and developing a new type of room-temperature, one-component, moisture-type product. Therefore, they conducted tests to seek patent protection. The inventors collected and analyzed the basic data necessary for mass production through model tests. • Room temperature, one-component, moisture-curing model test; (a) Reaction apparatus; A stirring rod with a thermometer was set inside a 10 ml glass sample tube (outer diameter 21 mm, height 40 mm), a cap made of polyethylene / cellophane tape (registered trademark) composite sheet was made and placed over the sample tube, the stirring rod with a thermometer was enclosed inside and the cap was sealed to create a sample tube for the reactor. The cap was provided with a blow nozzle for replacing N2 gas inside the tube and an inlet for introducing the liquid agent (main agent, hardener). (b) The above sample tube was set in an aluminum heating block (100 mm square x 20 mm thick, central sample tube installation section (outer diameter 23 mm x depth 15 mm)) that had been preheated to 100°C, and the inside of the tube was replaced with N2 while blowing N2 gas through it.

[0034] (3) Prepolymer synthesis; (c) First, while blowing N2 gas through the N2 gas inlet, 0.98 ml (8.53 mg equivalent) of the main component (A1) Coronate MX was added. Then, similarly, 0.66 ml of the curing agent (B1); P400 / octanediol (70 / 30 mass%) mixture (pre-filled in a 1 ml PP disposable container; 4.24 mg equivalent) was dropped in. Then, the inlet and other openings were quickly closed with adhesive. It was left to stand for about 1 minute. During this time, the two added liquids did not mix due to differences in specific gravity and polarity, and the liquid temperature (internal temperature) remained at 100°C, separating into two layers (lower layer A). No mixing or exothermic reaction was observed. The equivalent ratio of the raw materials (NCO / OH ratio) was 2.01 / 1.00. (d) Next, when the two liquids were vigorously manually mixed, the reaction started almost instantaneously, generating a rapid heat generation and causing the temperature to rise. After about 30 seconds, the liquid temperature reached about 140°C, and upon confirmation, the reaction tube was immediately removed from the heating block and air-cooled. The resulting liquid (liquid temperature A1; 130°C) was a colorless, bubble-free, easily flowing liquid. As the air-cooling time was extended, the liquid temperature decreased, and at liquid temperature A2 (100°C), the viscosity of the fluid increased. After about 20 minutes, it remained fluid up to about 80°C, and at about 35°C, a pale yellowish-brown, high-viscosity solid was obtained. (e) When the reaction tube was placed back on the aluminum block and reheated, the fluidity increased with the rise in liquid temperature. The fluidity at liquid temperatures of 100°C and 130°C was approximately the same as before cooling, confirming the thermal reversibility of the fluidity of the prepolymer composition.

[0035] (4) Evaluation of the cured product; After reheating (130°C), the fluid was collected and, in order to evaluate the product, the cap was removed and the fluid was taken out with an internally inserted stirring rod. The fluid was then applied in a strip across the entire surface of a 100mm square PP plate (thickness 0.1-2mm, width 3-10mm), left at room temperature (indoors) (measured over 1-30 days), and moisture curing properties (after 1 day) and other cured product properties (flexural strength, heat resistance) were measured. The applied material converted to a thermosetting type due to moisture curing, exhibiting tough strength and heat resistance of approximately 130°C or higher (meaning crosslinking formation). The results of the series of tests are shown in [Table 2].

[0036] Significance of the Model Test: (1) This model test is a batch method and differs from the continuous method of the present invention. However, in the continuous method, a two-component precision quantitative mixer (discharge volume variation of 1 ± 0.03) is used to continuously feed agent A / agent B at a constant ratio into a heated mixing reactor. Therefore, it can be said that there is virtually no difference between this model test and the continuous method. Of course, the amount of reaction heat etc. will differ depending on the feed amount, but this should be easily understood by developers in this field. Through this model test, insights were gained regarding the heated fluidity of the produced prepolymer, ultra-short time setting properties near room temperature and low-temperature setting temperature (high tackiness), and moisture curing properties. From this fact, it became possible to develop a continuous manufacturing method for a room-temperature one-component moisture-curing prepolymer and the product thereof. (2) In addition, the inventors have conducted a continuous model test (using a commercially available static mixer (made of SUS; internal volume ≈ 1.0 ml, 27 mixing elements) for the heating reactor / mixer, and replacing the two-liquid supply section with a precision metering pump, they have used two 5 ml disposable PP bottles (for agent A and agent B), and have confirmed the continuous production of prepolymers by synchronously discharging the two liquids into the reactor via silicone rubber (to secure the introduction flow path for the two liquids into SM). (3) Based on the model test in (1), it is expected that applying the relationship between the large amount of reaction heat generated (selection of two reactive substance species, adjustment of formulation, adjustment of catalyst addition amount, etc.), i.e., the amount of heat generated, to a model of an actual manufacturing machine (by conducting computer simulations, etc.) and designing the reactor will lead to improved energy efficiency. The test results for (1) are shown in Table 2.

[0037] See Figure 1.

[0038] Example 3. Figure 1 shows a conceptual diagram of the entire apparatus. Figure 1-1 shows a two-component moisture-curing prepolymer, Figure 1-2 shows a continuous manufacturing apparatus for a one-component moisture-curing prepolymer, and Figure 1-3 shows a manufacturing diagram of the one-component product.

[0039] [Figure 1-1 describes the two-component apparatus. This is a conceptual diagram of the manufacturing apparatus of the present invention. (a) Two storage containers (10, 20), and (a') Two raw material containers (11, 21), (b) Two precision quantitative dispensing machines (e.g., gear pumps (31, 32), (c) Switching valves (41, 42), (d) Reactor (50, discharge section 60), and (a)~(d)), connection parts, piping, sealing parts for connecting the components, and (e) various densifier parts (mass, temperature, color tone, etc.) and overall operation and control unit (power supply system and sequence, computer data processing and data storage, etc.). In this figure, (e) is omitted because the control technology of a known commercially available two-component reaction apparatus can be used, and is also disclosed in the inventor's prior invention (Patent Document 1). A prerequisite for using this apparatus is to constantly maintain a moisture-free state. (a) Two-component storage container; (10,20) Any material can be used, such as metal, glass, or plastic, as long as moisture barrier properties are maintained, but PP (polypropylene) is preferable in terms of ease of handling, light weight, and transparency. While the reaction liquids (Agent A and Agent B) can be stored directly, in this invention, a double-layer structure is preferable because it is used as a protective device for the product storage liquids (Agent A (11) and Agent B (21)). This is because it facilitates the operation and management of the storage container. In particular, if the isocyanate storage liquid is stored directly in the container, after use, the storage liquid will adhere firmly to the container (solidify due to moisture contamination), making it difficult to remove the hardened layer and significantly reducing operability. The raw material storage liquid is a dehydrated and defoamed product used as a blended product in a separate process, and the container material for the raw material storage liquid is preferably, but not limited to, a thin-layer multilayer (metal / film (PP)) that is meterable and moisture-impermeable. Alternatively, a thin-layer PP cup or the like can be placed inside the storage container and the product can be filled into it directly, but this is not the only possible method.

[0040] (b) Precision quantitative dispensing devices ((31, 32); Precision gear pumps, microgear pumps, mono pumps, and other precision quantitative pumps are used. The discharge volume can be precisely controlled by controlling the effective discharge volume of the pump and the pump rotation speed, making them very useful. Volumetric metering methods such as positive load metering and plunger metering are also effective. Devices that can consistently and stably dispense a precise quantitative volume through precision machining can be used. The discharge volume accuracy must be within ±3% of the standard discharge volume.

[0041] (c) Switching valve ((41, 42)) is useful for supplying the two-component reaction solution to the reactor via a pump. The switching valve is not strictly necessary, but it is useful to install it considering sudden accidents and maintenance inside the reactor (measures against product gelation, hardening, etc.). An example of replacing the reaction solution inside the reactor with polyol (both liquids via (41), shown by the dotted line in the figure) using the switching valve is shown. This greatly improved the operability inside the reactor. If the switching valve is not used, it is also possible to directly replace and clean the reactor with liquid B (polyol) via a pump. The advantage of polyol replacement in the present invention is that it is not necessary to completely replace the inside of the reactor, and work can be resumed while maintaining a polyol excess system (liquid state), resulting in good operability.

[0042] (d) Reactor; The reactor can be operated using only the heat of reaction without heating, or with a heater used as an auxiliary heating device. Two energy-saving methods are also possible. The choice of method depends on the reaction system (e.g., the amount of heat of reaction or the ease of controlling the heat of reaction). However, the reaction may be restricted due to insufficient heat of reaction, so it is desirable to use a heater in combination. If the heat of reaction is very large and difficult to control, it is effective to give the reactor a cooling function. The reactor structure is shown in Example 4 (Figure 2) below. It is desirable for the heater structure to be separate from the reactor. In addition, both static stirring (stack mixer method) and dynamic stirring can be used for stirring the reactor. In this figure, the stack mixer method, which has a simpler structure, is shown as an example. However, considering product manufacturing, the dynamic stirring method is considered superior in terms of operability and equipment maintenance. In the case of dynamic stirring, it is connected to a stepping motor via a coupler.

[0043] One-component continuous manufacturing apparatus; As shown in Figure 1-2, by equipping the reactor discharge tip with (f) a product storage container (70), it is possible to manufacture a one-component moisture-curing prepolymer continuous manufacturing apparatus using the same technology as the two-component apparatus described above. The discharge tip and the storage container (f) may or may not be connected to a pipe (Teflon®), and the (f) container may be either a simple receiving container or a product container. When obtaining the discharge liquid by installing (f) (70), measures such as blowing dry air are necessary to avoid the inclusion of moisture. The receiving container structure is not particularly limited. The receiving container material must be moisture-impermeable, and for product use, it is desirable that it be heat-sealable. A composite sheet as shown in Figure 1-3 is desirable, but it is not limited to this.

[0044] A one-component storage container and a room-temperature, one-component, moisture-curing product; as shown in Figure 1-3. The heat-fluid prepolymer produced in the two-component reactor is filled into the product storage container (70) via the discharge port (60), and when the filling liquid reaches near the top of the container, the top is fused together by heat sealing (62), etc. The product discharge port (63) at the bottom of the figure is closed from the beginning. For use, the port is opened and discharged, and the product is cured by moisture. By using this apparatus, a room-temperature, one-component product can be produced continuously and economically with inexpensive equipment. Furthermore, the product can be used manually (by hand pressure) at around 25°C (viscosity of 1 million mPa / s or less), and because it has excellent initial adhesion and bonding properties, it is useful as a household product (Example 2; see Table 2).

[0045] See Figure 2.

[0046] Example 4. Reactor Conceptual Diagram (a) Reactor structure, water-cooled type (2A); An example of this type is shown in Figure 2. It consists of the reactor body (2A10), reactor top cover (2A11), stirrer (2A12), seal section (2A15), intake ports for agent A and agent B (2A16, -17), discharge port (2A18), water-cooled structure section (2A13), and insulation section (2A14). The water-cooled section / insulation section (integrated) can be easily attached to and detached from the reactor body, and is used to cool the body and control the temperature when the reaction heat of the two liquids is excessive. The cooling section has a structure in which a metal tubing (pipe) is wrapped around the body via a heat-resistant film (Teflon®, etc.). Temperature control is performed by measuring the temperature with a thermograph and by automated control by a computer. (b) Reactor heating method (2B); Basically, it adopts a structure similar to the water-cooled method and is used supplementarily when the predetermined reaction temperature and time cannot be maintained due to insufficient reaction heat. The heating method is integrated with silicone rubber and insulation and is used by inserting and detaching it from the main body, but is not limited to this. A dynamic mechanical stirring method (stepping motor method) is assumed for the stirring method. The reason for adopting a dynamic method is that it is easy to manufacture the equipment, it can handle various reaction liquids (viscosity, structural viscosity, etc.), and it is easy to maintain, making it suitable as the equipment for the manufacturing method of the present invention. (d) Reactor design / simulation; (2C); Since the purpose is to manufacture small quantities of many different products, the reactor capacity has not been specified at this stage, but currently, an internal volume of approximately 3 to 10 ml and a continuous discharge rate of approximately 30 ml / min per minute are assumed. The main body will be made of metal (SUS, brass, copper, aluminum, etc.), and the reactor design will be optimized through computer simulation processing of the main body wall thickness (approximately 5 mm), discharge rate (raw material feed amount) ~ heat generation, specific heat of raw materials, heat capacity of metal (specific heat, specific gravity, mass), etc., and will be determined while verifying with experimental results. Initially, it is desirable to start with a small-capacity system to confirm safety due to heat generation. However, it is not limited to these.

[0047] [Table 3]

[0048] Example 5.6 Summary of the present invention Examples 1 to 4 of the present invention and comparative examples (current one-component RHM and current two-component mixed type) are shown in Table 3, and the evaluation and usefulness of the present invention are discussed. From the results in Table 3, the present invention is (a) Compared to the current single-component RHM, it is considered to be superior in terms of energy efficiency, ease of use compared to adhesive RHM, and cost-effectiveness. In terms of performance, it is expected to be about the same. (b) Compared to the current room-temperature two-liquid mixing type, the present invention demonstrates superior short-time setting properties, and has shown that it improves upon the weaknesses of the said mixing type (slow setting and poor operability (gelation in the mixer)). (c) Furthermore, the present invention has demonstrated a new continuous manufacturing method for moisture-curing one-component products, and the significant advantage of being able to manufacture one-component products using the same technology as the two-component products of the present invention. Moreover, because the one-component product has a low setting temperature near room temperature, it has been found to be capable of becoming a room-temperature one-component moisture-curing (adhesive to bonding) product. (d) Furthermore, this room-temperature, one-component, moisture-curing product has a fast moisture-curing rate, and polyurethane is expected to be superior in terms of strength (flexibility, toughness, and tear strength) due to its high cohesive force in its molecular structure. Although not partially described in the table, current one-component, moisture-curing products (modified silicone products) that may become competitors in the future have weak cohesive force and an initial bonding strength of about 5 to 10 minutes, so it is thought that this product can be developed as a new material that complements current one-component products and current one-component, moisture-curing RHM. Based on the above, I believe the advanced nature and usefulness of this invention will be understood. [Brief explanation of the drawing]

[0049] [Figure 1] This is a conceptual diagram of the entire apparatus of the present invention. Figure 1-1 is a conceptual diagram of a two-component moisture-curing prepolymer manufacturing apparatus. Figure 1-2 is a conceptual diagram of a one-component moisture-curing prepolymer manufacturing apparatus. Figure 1-3 shows the storage structure of a one-component moisture-curing prepolymer and a concept of the product. [Figure 2] This is a conceptual diagram of the reactor structure of the present invention. [Explanation of Symbols]

[0050] 10. Storage container (Agent A) 20 Same as above (Agent B) 11. Raw material storage container (Agent A) 21 Same as above (Agent B) 31. Gear pump (Agent A) 32 Same as above; Agent B 41 Switching valve (Agent A) 42 Same as above (Agent B) 50 Reactors 60 Discharge part 70 Product storage container (single-component type) 63 One-component moisture-curing products 62 Same as above (product discharge port) 2A10 Reactor body 2A11 Reactor top cover 2A12 Stirrer 2A13 Water cooling pipe (cooling section) 2A14 Insulation section 2A15 Seal part 2A16 Agent A supply port 2A17 Agent B supply port 2A18 Discharge port 2B15 Heating part (heater)

Claims

1. A method for producing a two-component moisture-curable polyurethane prepolymer using an apparatus that simultaneously manufactures and dispenses / coats the prepolymer, wherein liquid A mainly consists of a diisocyanate with a viscosity of 5 to 100,000 mPa·s and a vapor pressure of 1 Pa or less at 25°C, and liquid B mainly consists of a diol with a viscosity of 50 to 50,000 mPa·s at 25°C, and the two liquids are supplied to a reactor under anhydrous conditions while being heated, with the variation of the desired reaction ratio of the two liquids (NCO / OH group ratio) being within the range of 1 ± 0.05, and this ratio being constantly maintained. A method for producing a two-component moisture-curable polyurethane prepolymer, characterized by a CO / OH group ratio of 1.3 / 1 to 3.0 / 1, a reaction temperature of 60 to 170°C, and a reaction time of 2 to 120 seconds, wherein the prepolymer obtained by reaction exhibits fluidity at the heating temperature and high adhesion to adhesion at 25°C, and the vapor pressure of the prepolymer (diisocyanate) discharged from the discharge port at the bottom of the reactor is less than or equal to the TWA value (permissible concentration for inhalation toxicity; converted to vapor pressure, 0.45 mPa) at 50°C, and excellent safety at room temperature, short-time adhesion, and moisture curing properties.

2. The method for producing a two-component moisture-curable polyurethane prepolymer according to claim 1, characterized in that the diisocyanate content is 70% by mass or more relative to the total polyisocyanate, and the diol content is 70% by mass or more relative to the total polyol.

3. A method for producing a two-component moisture-curable polyurethane prepolymer according to claim 1 or 2, characterized in that the heated state is obtained by the reaction heat from the two-component reaction or by using an external heater in combination.

4. A method for producing a two-component moisture-curable polyurethane prepolymer according to claim 1, characterized in that the reaction time is 2 to 30 seconds.

5. The method for producing a two-component moisture-curable polyurethane prepolymer according to claim 1, characterized in that the high tackiness to adhesion of the prepolymer at 25°C is such that the viscosity is 50,000 to 1,000,000 mPa·s, or the adhesion temperature is 20°C to 50°C.

6. A method for producing a two-component moisture-curable polyurethane prepolymer according to claim 1, characterized in that the short-time setting time is 2 to 60 seconds.

7. A prepolymer manufacturing apparatus used in the method for manufacturing a two-component moisture-curable polyurethane prepolymer according to claim 1, characterized in that the heater for creating a heated state can be easily inserted into and removed from the reactor.

8. The apparatus for producing a two-component moisture-curing polyurethane prepolymer according to claim 7, characterized in that it comprises (a) a storage container for two liquids, (b) a precision quantitative dispensing machine, (d) a reactor having a supply unit and a dispensing unit, a connecting unit and connecting piping for connecting (a) to (d), and (e) a unit comprising a reaction liquid, various sensors for confirming the reaction product and a control unit, and having means for confirming the product.

9. The apparatus for producing a two-component moisture-curing polyurethane prepolymer according to claim 8, characterized in that the storage container in (a) above is a separable double container.

10. The apparatus for producing a two-component moisture-curing polyurethane prepolymer according to claim 7, characterized in that the switching valve in (c) above has a piping configuration that allows it to be replaced with a polyol in order to prevent gelation of the produced prepolymer in the reactor during and after the reaction.

11. The apparatus for producing a two-component moisture-curing polyurethane prepolymer according to claim 7, characterized in that the prepolymer produced in the reactor is directly discharged from the reactor discharge section and a product storage container (f) for storing the product is provided.

12. The apparatus for producing a one-component moisture-curable polyurethane prepolymer according to claim 11, characterized in that it can continuously produce a one-component moisture-curable polyurethane prepolymer.

13. A polyurethane prepolymer manufactured by the apparatus for manufacturing a one-component moisture-curing polyurethane prepolymer described in claim 12, characterized in that it can be used at or near room temperature.

14. The room-temperature, one-component, moisture-curing polyurethane prepolymer according to claim 13, characterized by being an adhesive, coating agent, sealant, or molding material.

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