Process for producing two-component and one-component moisture-curable polyurethane prepolymers, and production apparatus, which are excellent in safety, short-term fixability, and moisture-curability

Abstract

Provided are a production method and a production apparatus for two-component and novel (usable even at normal temperature) one-component moisture-curing polyurethane prepolymers, which achieve diversity, compatibility between safety and environmental friendliness, further improvement in product manufacturing technology and performance (quality), energy saving, and improvement in ease of operation. 【Solution means】Regarding the above two-component and one-component types, safety was improved by using a safe monodiisocyanate with a low vapor pressure. Also, quality improvement was achieved by enhancing the accuracy of the constant reactivity ratio of the two agents. In addition, for the one-component type, a product storage machine was added to the apparatus, and continuous production of the one-component moisture-curing prepolymer and the apparatus were produced economically. As a result, it led to the development of a novel normal-temperature one-component moisture-curing 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 adhesiveness to fixing) at room temperature, product reliability, and moisture curability. Furthermore, it relates to a continuous production method and a production apparatus for a one-component prepolymer obtained by using the production apparatus, and a product thereof.

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). The PURHM has easy fluidity under heating and forms instant high adhesiveness to solidification by cooling at room temperature under moisture barrier. However, once it is fixed, through the moisture absorbed from the air and the adherend surface 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 field in the industry.

[0003] While the current PURHM has the above advantages, it 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. 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, so it is necessary to heat the entire apparatus including pipes and discharge parts, and a large amount of energy is consumed during use. In contrast, the two-component type of this 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] In order to solve the problems of the current one-component method, the present inventor has been consistently researching energy-saving PURHM. As a result, in the prior invention (abbreviated as the prior invention), focusing on the high reactivity of polyurethane and the reaction without by-products, a method for stably synthesizing a moisture-curing terminal isocyanate prepolymer directly from two raw materials in a short time in a heated reactor was found, and an energy-saving, easy-to-operate, and economical new manufacturing method that integrates so-called manufacturing and product use and can be used as a product as it is was invented. Already, in the prior invention, [a product evaluation method was disclosed in the manufacturing apparatus and system (Patent Document 1). Also, in order to improve the safety of the raw material isocyanate, [a method for reducing residual monomers] (Patent Document 2) was disclosed. Furthermore, improvement of the problem of foaming of the cured product during moisture curing was disclosed (Patent Document 3).

[0005] On the other hand, energy-saving room-temperature two-component reaction-curing types (such as polyurethane, epoxy, acrylic, silicone, etc.) that are in a competitive relationship with the present invention are suitable for obtaining diverse and high-performance physical properties, but generally have the weakness of slow curing speed and lack of high productivity. If it is made into a fast-curing type, gelation (curing) due to the mixing of the two components in the mixer may occur, and there is a risk of blocking the mixer. In the current technology, the shortest time for suppressing gelation at room temperature is about 2 to 5 minutes. As a countermeasure against this gelation, the present inventor disclosed an improvement measure (Patent Document 4) in the prior invention (two-component mixing fast-curing polyurethane), but problems remained in terms of operability.

[0006] The present inventor has intensively studied to solve the problems of the current one-component PURHM and the current room-temperature two-component reaction type while integrating the advantages of both. However, in order to achieve the above integration, there was still room for improvement in this technology (prior application invention). The first is that the raw material isocyanate requires attention in handling due to safety and environmental properties. Moreover, since the present invention is used under heating, safety evaluation, improvement, and confirmation were urgent tasks. It was necessary to review and appropriately evaluate the raw materials (especially polyisocyanates (Non-Patent Documents 1 and 2)). The second is that polyurethane is excellent in high-speed reaction and generates a large amount of reaction heat during the process. It was necessary to further consider the utilization of the reaction heat and the improvement of the reactor to save more energy. Thirdly, the two-component device of the present invention was improved to develop a one-component continuous manufacturing device with a more stable feeling during use using the same technology and a one-component product that can be used even at normal temperature. The present inventor has studied this and dedicated himself to the improvement of this technology.

[0007] In addition, the terms used in the present invention are defined as follows. · Regarding "moisture-curing polyurethane reactive hot melt": The current manufacturing method (product) is differentiated from the one-component type and the present technology is differentiated from the two-component type. · "Continuous manufacturing of the present invention" shall include "intermittent manufacturing associated with on-off manufacturing of products, etc.". · Regarding the normal temperature described as liquid at normal temperature, considering the recent global warming, it shall include a slightly heated state (near normal temperature; ≒ 35°C or less). · Regarding "high adhesion ~ fixation": There is no strict distinction between the two. "High adhesion" refers to a high-viscosity liquid state. Fixation indicates a property closer to "solidification". The viscosity is higher for fixation than for high adhesion. · Regarding "discharge" and "coating": There is no strict distinction. Coating refers to coating on the adherend after discharge. · "Prepolymer of the present invention": Under moisture barrier and at a specified heating temperature, it exhibits heat fluidity (thermoplasticity), and when it comes into contact with moisture (water), it exhibits a three-dimensional network structure of "gelation, (precursor of cross-linked body) and cross-linked body". · Regarding "cross-linked body" and "cured body": There is no strict distinction, and the cured body of the present invention refers to a heat-cured type cured body. · Regarding the handling of the vapor pressure values shown in the present invention: The vapor pressure handled in the present invention deals with a very small region. Therefore, special equipment and special technology are required for the measurement of measured values. The values used in the present invention are the values from authoritative publications and the values derived (calculated) from polymer and general chemical theories. In addition, the vapor pressures of the generated prepolymer at 100°C and 50°C are the values obtained from the virtual diagram shown in Table 1. [Patent Document 1] Japanese Patent Publication No. 5044749 [Patent Document 2] Japanese Patent Publication No. 5853295 [Patent Document 3] Japanese Patent Publication No. 6698981 [Patent Document 4] Japanese Patent Publication No. 5422282 [Non-Patent Document 1] Materials of the Japan Urethane Industry Association (Table 7, Separate Table 1) [Non-Patent Document 2] MSDS of the Urethane Raw Material Industry Association, Polymeric MDI; dated February 8, 2023; 5 pages) [Non-Patent Document 3] Course of Polymer Chemistry, written by Minoru Imoto and Ryichi Fujishiro, in 1967 [Disclosure of the Invention] [Problems to be Solved by the Invention]

[0008] The present invention is a further improvement in the method for producing a moisture-curable terminal isocyanate prepolymer composition that integrates the production and coating of a prior invention. That is, it is the diversity of the present invention, the compatibility of safety and environmental protection, the further improvement of product manufacturing technology and performance (quality), energy conservation, and the improvement of ease of operation. Regarding this technology, by adding new knowledge to the long-cultivated technology and completing a technology that has never existed before, the problems of the prior art are solved, and a method and apparatus for producing two-component and novel (usable even at room temperature) one-component moisture-curable polyurethane prepolymers are provided. [Means for Solving the Problems]

[0009] The inventor of the present invention has intensively studied the above problems. By adding new knowledge and solving the problems of the prior art, a method and apparatus for producing a novel moisture-curable polyurethane prepolymer could be provided

[0010] That is, the present invention consists of the following inventions. (1) A method for producing a two-component moisture-curing polyurethane prepolymer, using an apparatus that simultaneously manufactures and discharges / applies a prepolymer. Component A is a liquid diisocyanate with 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 -2 Pa) or less, as the main component. Component B is a liquid diol with a number average molecular weight (Mn) of 62 to 15,000 and a viscosity at 25°C of 50 to 50,000 mPa·s as the main component. The two components have a variation in the reaction ratio of the desired two components within the range of 95 to 105 (abbreviated as 1 ± 0.05) based on 100, preferably in the range of 1 ± 0.03, and are supplied to a substantially anhydrous reactor in a heated state while constantly maintaining this ratio. The prepolymer obtained by reacting at 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 heating temperature and high tack to fixation at 25°C. The vapor pressure of the prepolymer (diisocyanate) discharged from the discharge port at the lower part of the reactor at 50°C is at or below the TWA value (vapor pressure conversion; 0.45 mPa). It is characterized by excellent safety, environmental friendliness, energy saving, operability, short-time fixation at room temperature (high tack to fixation), product reliability, and moisture-curing properties. This is a method for producing a two-component moisture-curing polyurethane prepolymer.

[0011] (2) The method for producing a moisture-curing polyurethane prepolymer according to claim 1, wherein 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 a state obtained by using the heat of reaction of the two liquids or an external heater, and it is the method for producing a moisture-curing polyurethane prepolymer according to the above (1) or (2). (4) The reaction time in the above is 2 to 120 seconds, preferably 2 to 60 seconds, more preferably 2 to 30 seconds, and most preferably 1 to 15 seconds, and it is the method for producing a moisture-curing polyurethane prepolymer according to any one of the above (1) to (3). (5) The high tack to fixing property of the above prepolymer at 25°C is either a viscosity of 50,000 to 1,000,000 mPa·s or a fixing temperature of 20°C to 50°C. (6) The short-time curability time in the above is 2 to 120 seconds, preferably 1 to 30 seconds, more preferably 1 to 15 seconds, and it is the method for producing a moisture-curing polyurethane prepolymer according to any one of the above (1) to (5).

[0013] (7) A manufacturing apparatus for manufacturing the prepolymer of the above (1), wherein the heater for forming the heating state is a manufacturing apparatus for a moisture-curing polyurethane prepolymer that can be easily inserted and removed from the reactor. (8) The manufacturing apparatus of the above (7) may or may not have two each of (a) a storage container, (b) a precision metering dispenser, a switching valve that can be replaced with a polyol (both two liquids or one liquid) as needed to prevent gelation of the prepolymer produced in the reactor during and after the reaction, and (d) a reactor having one supply part and one discharge part, a connection part and connection pipes for connecting the above (a) to (d), and (e) various sensors and a control part for confirming the reaction product, and it is a manufacturing apparatus for a moisture-curing polyurethane prepolymer having a means for confirming the product. (9) The structure of the above (a) storage container includes a container having a double structure. (10) The above switching valve is preferably at least a three-way valve, and has a piping configuration that can be replaced with a polyol (both two liquids or one liquid) as needed to prevent gelation of the prepolymer produced in the reactor during and after the reaction.

[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 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 prior invention by the present inventor, that is, to expand the diversity of the present invention, 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 industry.

Best Mode for Carrying Out the Invention

[0016] · First, the present invention (measures for improving the problems of the prior invention, etc.) will be outlined below, and the details will be described in the examples. · Improvement in safety and environmental performance; Safety and environmental performance are the most important issues for users. There are concerns about the safety of raw material polyisocyanates, especially under heating conditions. In particular, since the present invention is carried out in a heating system, although it is a sealed system, great care must be taken with 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 shown 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 generated 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 a room temperature liquid polyisocyanate and a 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 crosslinking body formation and converted into a thermosetting hardening body (three-dimensional network structure). The present invention is a manufacturing method for two-component and one-component moisture-curing prepolymers that are precursors of the hardening body.

[0018] (2) Raw material polyisocyanate (Liquid A) On the premise of satisfying the isocyanate vapor pressure described above, all isocyanates that satisfy the following conditions can be used regardless of whether they are monomers or prepolymers. That is, they are bifunctional to trifunctional polyisocyanates that are liquid at room temperature and low molecular weight NCO-terminated prepolymers at both ends, and those with viscosities not particularly restricted and can be accurately discharged by a precision metering dispenser can be used. Usually, a range of 50,000 to 100,000 mPa·s is convenient for stable discharge. The above polyisocyanates and NCO-terminated prepolymers are usually used in a mixed state, and all systems without phase separation and with good miscibility can be used. The above polyisocyanates are bifunctional (mainly composed of diisocyanate (70% by mass or more), and those containing a part of trifunctional (triisocyanate) are also used. The reason for using diisocyanate as the main component is that it is suitable for obtaining the NCO-terminated linear prepolymer (thermoplastic) of the present invention. Among all the polyisocyanate components, the diisocyanate component is 70% by mass or more, preferably 80% by mass or more. In other words, an average functionality (Fn) of 2.3 to 1.8, preferably 2.1 to 1.9 is appropriate. The number average molecular weight (Mn) is appropriately in the range of 150 to 10,000, which is suitable for the production of multiple varieties of the present invention. However, it is not limited to this.

[0019] The reaction rate of the polyisocyanates used follows the order of aromatic > alicyclic > aliphatic. As an example of the aromatic type, the aforementioned MDI is a typical example. In the case of a catalyst-free system (MDI / polyol; 2 mg equivalent / 1 mg) equivalent mixture, the temperature rose by 30 to 50 °C within a few seconds. By effectively utilizing this reaction heat, further promotion of energy conservation is expected. As an example of the alicyclic type, the IPDI (isophorone diisocyanate) system is useful. Emphasizing safety, it is appropriate to utilize it as the raw material for the low molecular weight NCO prepolymer with both ends. As an example of the aliphatic type, there is the HDI system (hexamethylene diisocyanate), but HDI has a slow rate, a high vapor pressure, and has difficulties in use as a single substance. However, similar to IPDI, if prepolymerized and the remaining monomer is removed, it is useful as a raw material (see Table 1). There are commercially available products for this. For this raw material, high-speed reaction (high heat generation) was confirmed in a high-concentration addition system with a large amount of catalyst. Also, since the present invention emphasizes the effective utilization of reaction heat, the MDI system is appropriate. A large number of MDI system experiments were conducted in the prior invention (Patent Document 3). The system suitable for the present invention was selected from among them and further confirmed by additional experiments.

[0020] Examples of liquid MDI systems useful for safety and energy conservation are shown below: (a) MDI (diphenylmethane diisocyanate; (4,4’MDI, 2,4‘MDI, 2,2’MDI isomers or isomer mixtures), (b) carbodiimide-modified diisocyanate, uretdiimine-modified isocyanate (c) a terminal MDI-containing prepolymer obtained by reacting excess MDI with a diol, or (d) a blend of the terminal MDI-containing prepolymer and a 4,4‘MDI monomer, etc. Many of the room-temperature liquid terminal NCO prepolymers of (c) can be easily prepared by reacting with short-chain diols or low-viscosity diols under excess MDI, and these are also useful as raw materials. Also, many are supplied as commercial products. As an example, Coronate MX, Coronate MT, Coronate 1050, Millionate NM, Millionate MR200, etc. (above, Tosoh Corporation). Also, castor oil-modified terminal NCO prepolymers (URIC N2023; Ito Oil Co., Ltd.) etc. are mentioned, and are supplied by several other companies. These commercial products can all be used alone or as a mixture. The raw materials of the present invention are not limited to these.

[0021] (3) Polyol raw material (Component B); A diol with an average functionality of 2 for the polyol that is liquid at room temperature (25 °C) is most desirable, but it may also contain a triol with a functionality of 3 (trifunctional). Similar to the above diisocyanate, it is difficult to obtain a pure product due to impurities, side reactions, moisture absorption during storage, etc. If the diol component content rate is 70 mass% or more in the total polyol component, it can be used. Desirably, it is 80 mass% or more. In other words, the average functionality (Fn) is 2.3 to 1.8, preferably 2.1 to 1.9. Also, for the average molecular weight (Mn), 62 to 15000 is appropriate. As these diol raw materials, the main chain structure includes polytetramethylene ether-based, polyethylene oxide-propylene oxide polyether-based, polyester-based, polycarbonate-based, castor oil-modified-based, etc., and is usually selected from diols described in urethane chemistry. Polyether diols are useful in terms of low viscosity, and polycarbonate diols are useful in terms of hydrolysis resistance and strength, and polyester diols are useful in terms of enhancing heat resistance.

[0022] Furthermore, short-chain diols as chain extenders with 3 to 10 carbon layers are also useful. They 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, a small amount of trifunctional glycerin, trimethylolpropane, etc., and can be used within the range that does not reduce the heat fluidity of the prepolymer. These diols can be used alone or as a mixed diol. However, the diols of the present invention are not limited to these.

[0023] (4) Catalyst; Since the MDI system of the present invention has a very fast reaction under heating, instantaneous synthesis (≒100 °C, about 1 to 30 seconds or less) is possible even in a non-catalytic system. The amount of catalyst added is greatly affected by the type of raw materials, the amount of raw materials used, and the reaction temperature. As a result, the heat generation amount also changes greatly. Therefore, from the perspective of ensuring safety (abnormal heat generation), it is better to carry out the reaction in a small amount system. However, since the present invention also pursues energy conservation, in order to make use of this high reactivity, a high addition of catalyst is effective for the HDI prepolymer system. The catalysts used are known catalysts used in ordinary polyurethane chemistry. Examples of these catalysts include organometallic compounds of tin, iron, titanium, or bismuth, such as dibutyltin dilaurate (DBTDL), dioctyltin dilaurate, etc., tin(II) salts of carboxylic acids, amine systems, etc., which are suitable as catalysts used in the present invention. The concentration of the catalyst in the composition used is about 0.0001 to 1.0% by mass, preferably 0.005 to 0.05% by weight, more preferably 0.05 to 0.002% by mass. Catalysts described in ordinary polyurethane chemistry are used.

[0024] (5) Additive; The addition of additives is useful in the present invention. If desired, stabilizers, adhesion promoters, fillers, tackifiers, pigments, antioxidants, ultraviolet absorbers, etc. can be contained. In particular, the addition of various inorganic powders and metal powders from which substantial moisture has been removed as fillers can lower the prepolymer concentration in the composition, and as a result, the reduction of the raw material monomer can lower the vapor pressure of the monomer of the present invention, and a safer product can be obtained. Also, it has the effect of reducing the amount of carbon dioxide gas that causes foaming and reducing foaming. It is also useful for controlling (relieving) a large amount of reaction heat during the instantaneous synthesis of prepolymers. Also, an effect of adjusting the viscosity (adhesive strength, etc.) of the product can be expected. Furthermore, effects of improving various physical properties such as strength, heat resistance, weather resistance, water resistance, and chemical resistance of the cured product can also be expected. In the present invention, an improvement in adhesive strength is expected. Furthermore, reducing the product price also has great economic efficiency. Inorganic additives etc. (powders) can be obtained from the products of each company and can be appropriately selected according to the product of the present invention. The addition amount of the inorganic filler is affected by the product type, composition, shape, particle size, etc., but is at most 70% by mass or less. Preferably it is 50% by mass or less. Also, organic powders such as wood powder and algae powder are also useful. However, the present invention is not limited thereto.

[0025] (6) Prepolymer production conditions Next, the production conditions of the prepolymer will be described. Variation in the reaction ratio of the two liquids; Standard reaction ratio; As a result of examining measures for stabilizing and improving the quality of the present invention (two-component type), it is most important to always maintain the two raw material liquids within a certain range and supply them to the reactor for reaction. As described above, when the standard value of the reaction ratio of the two liquids is set to 1, conditions within the range of 1 ± 0.05, preferably 1 ± 0.03 are appropriate. Regarding keeping within this variation range, since the discharge accuracy of commercially available precision metering applicators for two-component reaction adhesives is within 1 ± 0.03, if these commercially available products are used and improved, the problems of this variation can be solved. Temperature; The reaction temperature is 60 to 170 °C, preferably 70 to 130 °C, more preferably 80 °C to 120 °C. At a temperature of 170 °C or higher, there is a risk of deterioration of the produced prepolymer and concerns in terms of safety (including vapor pressure). Also, at 60 °C or lower, 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, more preferably 2 to 15 seconds. NCO / OH group ratio; It is 1.3 / 1 to 3.0 / 1, preferably 1.3 / 1 to 2.5 / 1, more preferably 1.5 / 1 to 2.0 / 1. When the ratio is 3 / 1 or more, unreacted diisocyanate raw materials remain in excess, and there is a remarkable tendency to promote foaming during moisture curing, which is not preferable. Also, there is a risk of acting negatively in terms of safety.

[0026] (7) Properties of the produced prepolymer; Using the above polyisocyanatotonate (liquid A) and polyol (liquid B), produced under the above conditions Prepolymer viscosity; It is a moisture-curable (terminal NCO group) thermoplastic prepolymer, which exhibits fluidity under heating, and is instantaneously solidified by discharging as it is and air-cooling. The properties of the prepolymer are affected by raw material types (molecular weight, skeletal structure), molecular weight (NCO / OH group), etc. In particular, the viscosity behavior (fluidity under heating, and viscosity-to-adhesiveness at normal temperature) affects various properties. The present invention is rich in manufacturing various products and corresponding to various applications. The viscosity of the prepolymer alone is appropriately 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 thereto. Moisture curability; When discharging the heating fluid to the outside, it absorbs moisture in the air and on the adherend, and converts the moisture into a reaction source (amine crosslinking) to be converted into a thermoset hardening body (three-dimensional network structure). The moisture crosslinking rate follows the reactivity of the polyisocyanate, showing aromatic > alicyclic > aliphatic. The evaluation of moisture curability is the heat resistance temperature (by the constant rate heating method).

[0027] · The manufacturing apparatus of the present invention will be described in the section of the examples. 4. Examples; Hereinafter, the present invention will be described by examples. The present invention is not limited thereto.

[0028]

Table 1

[0029] Example 1. Safety evaluation and improvement: To evaluate the safety of raw material poly- and monomeric isocyanates, etc., referring to Non-Patent Document 1 and Non-Patent Document 2, six types (six types within the right frame) with different product types were selected as examples of the isocyanate in Table 1, and a vapor pressure diagram was created from the numerical values (three types) of the vapor pressure and boiling point at 25°C in 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)) showed a constant value regardless of the type of isocyanate. Applying this slope to the MDI system, a vapor pressure diagram (virtual diagram) of mono- and polymeric MDI with an unknown boiling point (300°C or higher) was created. As a safety index, inhalation toxicity was selected and estimated from the legal regulatory value (monomeric MDI). Since the raw materials used in the present invention are implemented in a heating system, it is necessary to select raw materials with a low vapor pressure. As the vapor pressure at 25°C, the allowable concentration for the human body (TWA; average concentration of normal workers for 8 hours a day, 40 hours a week) is stipulated to be 0.05 mg per cubic meter. When converted (calculated) to vapor pressure, it becomes 0.45 mPa, which is shown by the thick dotted line in the figure. The MDI (poly is 0.4 mPa and mono is 0.56 mPa) used in the present invention shows a lower vapor pressure than this regulated value, indicating that there is no safety problem.

[0030] In the present invention, the vapor pressure of 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 the actual use system, it is not used alone, and most of the diisocyanate is consumed in the prepolymer formation reaction with the polyol. In the NCO / OH ratio 2 / 1 system, it is theoretically consumed 100%, but a maximum of about 10% can be considered as unreacted. In addition, dilution and curing with polyols and fillers, and further reaction with water are also considered. Therefore, the decrease in the initial concentration of isocyanate (abbreviated as low vapor pressure treatment) is significant. Also, the decrease in concentration due to the treatment of residual monomers in the isocyanate prepolymer is significant. Including the above, the vapor pressure value of the present invention is limited.

[0031] Regarding this vapor pressure reduction, the inventor estimated that the initial concentration of the vapor pressure was reduced by at least ≒1 / 20. Based on this, the low vapor pressure treatment and the virtual diagram shown in Table 1 were created. In the present invention, although it is used in the heating system, even in that case, the vapor pressure at 50 °C is within the TWA for both pMDI and mMDI, indicating that the safety has been significantly improved. Also, the influence of prepolymerization is large. In the figure, it is shown that for HDI alone, the ≒1 Pa value becomes 1 / 100 or less of that of the monomer after prepolymerization by the residual monomer treatment (measurement of the concentration of HDI) (from the analysis values of the manufacturer). As a result, regarding safety, although the present invention is a heating system, it can be said that it is extremely safe. However, since the sensitization action varies among individuals, in order to achieve greater safety, improvement measures for the working environment such as wearing protective gear and installing exhaust facilities are important.

[0032]

Table 2

[0033] Example 2 Development of a room temperature one-component moisture-curing product · As a result of organizing the test results of the prior invention (Patent Document 3) and conducting some additional test runs, the inventor obtained ideas regarding the utilization of a large amount of heat generation and the development of a new type of room temperature one-component moisture-curing product, and thus conducted tests to patent it. The inventor 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 stirrer with a thermometer was set in a 10 ml glass sample tube (outer diameter 21 mmφ, height 40 mm). A cap made of a polyethylene / cellulose tape (registered trademark) composite sheet was fabricated, placed over the sample tube, and the stirrer with the thermometer was enclosed and the cap was sealed to create a sample tube for the reactor. Incidentally, the cap was provided with a blow-off port for replacing the N2 gas inside the tube and an inlet for the liquid agent (main agent, curing agent). (b) The above sample tube was set in an aluminum heating block (100 mm square x 20 mm thick) preheated to 100 °C, and the sample tube was set in the central sample tube installation part (outer diameter 23 mm x depth 15 mm). While blowing N2 gas, the inside of the tube was replaced with N2.

[0034] (3) Prepolymer synthesis; (c) First, while blowing N2 gas from the N2 gas inlet, 0.98 ml (8.53 mg equivalent) of the main agent (A1) Coronate MX was added. Next, in the same manner, 0.66 ml (previously filled with 1 ml of PP disposable liquid; 4.24 mg equivalent) of the curing agent (B1); P400 / octanediol (70 / 30 mass%) mixture was dropped. Then, quickly, the inlets and the like were closed with an adhesive. It was left standing for about 1 minute. During this period, the two liquids added were not mixed due to the difference in specific gravity and polarity, and the liquid temperature (internal temperature) was maintained at 100 °C and separated into two layers (lower layer A agent), and no mixing or heat generation due to the 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, and heat was generated rapidly, and the temperature increased. After about 30 seconds, the liquid temperature reached about 140 °C. After 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. At liquid temperature A2 (100 °C), the viscosity of the flowing liquid increased. After about 20 minutes, it showed fluidity up to about 80 °C, and a light tan, high-viscosity to solid state was obtained at about 35 °C. (e) The reaction tube was reinstalled in the aluminum block and reheated. As the liquid temperature increased, the fluidity increased. The fluidity at liquid temperatures of 100 °C and 130 °C was substantially the same as before cooling, respectively, and the thermoreversibility of the fluidity of the prepolymer composition was confirmed.

[0035] (4) Evaluation of the cured product; The flowing liquid after reheating (130 °C) was collected. To evaluate the product, the cap was removed, and the flowing liquid was taken out with a stirring rod sealed inside. The flowing liquid was applied in a strip shape over the entire surface on a 100 mm square PP plate (thickness, 0.1 - 2 mm, width 3 - 10 mm), and left at room temperature (indoors) (time-dependent measurement for 1 - 30 days). Moisture curability (after 1 day) and other cured product properties (flexural strength, heat resistance, etc.) were measured. The coated product was converted into a thermosetting type by moisture curing, and the strength was tough, and the heat resistance was approximately 130 °C or higher (indicating the formation of a crosslinked body). A series of test results are shown in [Table 2].

[0036] Significance of the model test: (1) This model test is a batch process, which is different from the continuous process of the present invention. In the continuous process, although a two-fluid precision metering mixer (variation in discharge volume: 1 ± 0.03) is used to continuously feed Agent A / Agent B to the heating and mixing reactor at a constant ratio all the time, it can be said that the test method is substantially the same as that in this model test. Of course, the reaction heat quantity, etc. will be different depending on the feed quantity, but it will be easily understood by developers in the industry. Through this model test, findings such as the heat flowability of the generated prepolymer, the ultra-short-time fixing property near room temperature, the low-temperature fixing temperature (high adhesiveness), and the moisture curability were obtained. From this fact, it led to the possibility of the continuous manufacturing method and product development of a one-component moisture-curing prepolymer at room temperature. (2) Also, separately, the inventor of the present invention has conducted a continuous model test (for the heating reactor / mixer, a commercially available static mixer (made of SUS; internal volume ≒ 1.0 ml, 27 mixing elements) is used, and the two-fluid supply part is replaced with precision metering pumps. Two 5-ml PP disposable ones are used (for Agent A and Agent B), and through a silicone rubber (ensuring the introduction flow path of the two fluids to the SM), the two fluids are discharged synchronously and continuously into the reactor, and a large number of continuous generations of prepolymers have been confirmed. (3) Through the model test in (1) this time, the reaction heat generated in large quantities (selection of two-fluid reactive substance types, formulation adjustment, adjustment of catalyst addition amount, etc.), that is, by applying the relationship of the calorific value to the actual manufacturing machine model (such as conducting computer simulations, etc.) and designing the reactor, it is expected to lead to an improvement in energy conservation. 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 device. Figure 1-1 is a two-component moisture-curing prepolymer, Figure 1-2 is a continuous manufacturing device for a one-component moisture-curing prepolymer, and Figure 1-3 is a manufacturing diagram of the one-component product.

[0039] The two-component type apparatus of Fig. 1-1 will be described. It shows 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 metering dispensers (e.g., gear pumps (31, 32)), (c) switching valves (41, 42), (d) reaction apparatuses (50, discharge part 60), and (a) to (d) connection parts, piping, and seal parts for connecting these members, and (e) various sensors (mass, temperature, color tone, etc.) and the overall operation / control part (power supply system, sequence, computer data processing, data storage, etc.). In this figure, for (e), since the control technology of a known commercially available two-component reaction type apparatus can be used and is also disclosed in the prior invention (Patent Document 1) by the present inventor, it is omitted. The prerequisite for using this apparatus is to always maintain a state under moisture barrier. (a) Two-component type storage containers; (10, 20) The material can be any of metal, glass, plastics, etc., as long as moisture barrier property is maintained, but PP (polypropylene) is desirable in terms of operability, light weight, transparency, etc. Although the reaction liquid agents (Agent A and Agent B) can be directly stored, in the present invention, since it is used as a protective device for the product storage liquids (Agent A (11), Agent B (21)), it is desirable to have a double structure. The reason is that it facilitates the operation and management of the storage containers. In particular, when directly storing an isocyanate storage liquid in the container, after using the storage liquid, etc., the storage liquid adheres strongly to the container (solidifies due to moisture mixing), and it is difficult to remove the cured layer, significantly reducing the operability. The raw material storage liquid is, in a separate process, a dehydrated and defoamed product used as a blended product. As the container material for the raw material storage liquid product, a thin-layer multi-layer (metal / film (PP)) with metering and moisture impermeability is desirable, but not limited to this. As an alternative method, a method such as providing a thin-layer PP cup, etc. inside the storage container and directly filling the product into it can be considered, but not limited to this.

[0040] (b) Precision metering and discharging device ((31, 32); precision gear pumps, micro gear pumps, mono pumps, etc., which are precision metering pumps such as these. The discharge volume can be accurately and precisely controlled by controlling the effective discharge volume of the pump, the pump rotation speed, etc., and is very useful. Also, volumetric metering methods such as the positive load metering method or the plunger metering method are also effective. Those that can constantly and stably discharge a precise metered discharge volume through precision machining can be used. The discharge volume accuracy needs to be within the range of ±3% of the standard discharge volume.

[0041] (c) Switching valve ((41, 42) is useful for supplying a two-component reaction liquid to the reactor via a pump. The switching valve is not necessarily required, but considering sudden accidents or maintenance inside the reactor (measures against gelation and hardening of the product, etc.), it is useful to install it. The replacement cleaning of the reaction liquid in the reactor with polyol (via (41), shown by the dotted line in the figure) using the switching valve was exemplified. As a result, the operability inside the reactor was greatly improved. Incidentally, when 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 there is no need to completely replace the inside of the reactor, and the operation can be resumed to the extent of maintaining a polyol excess system (liquid state), and the operability is good.

[0042] (d) Reactor; It is possible to implement the reactor in a non-heating method using only the reaction heat, a combined method using a heater as an auxiliary, or both energy-saving methods. Which method to adopt is selected according to the reaction system (such as the amount of reaction heat or the ease of controlling the reaction heat). However, since the reaction may be restricted due to insufficient reaction heat, it is desirable to use it in combination with a heater. When the reaction heat 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) described later. The heater structure preferably has a separated structure from the reactor. Also, as the stirring method of the reactor, either a static stirring method (static mixer method) or a dynamic stirring method can be used. In this figure, the static mixer method with a simpler structure is exemplified. However, considering the production of products, the dynamic stirring method is considered superior in terms of operability, equipment maintenance, etc. In the case of dynamic stirring, it is connected to a stepping motor via a coupler.

[0043] One-component continuous production device; By providing a (f) product storage container (70) at the tip of the reactor discharge part shown in FIGS. 1-2, it has been shown that it is possible to produce a continuous production device for a one-component moisture-curing prepolymer with a common technology with the previous two-component device. Whether the discharge tip and the storage container of (f) are connected by a pipe (Teflon (registered trademark)) or not is not necessary, and the (f) container can be either a simple receiving container or a product container. When obtaining the discharged liquid due to the installation of (70) of (f), measures such as blowing dry air are necessary to avoid the mixing of moisture. The receiver structure is not particularly limited. The receiver material should be moisture-impermeable, and it is desirable that it can be heat-sealed for products. Although the composite sheet shown in FIGS. 1-3 is desirable, it is not limited thereto.

[0044] One - component reservoir and room - temperature one - component moisture - curable product; as shown in FIGS. 1 - 3. The thermally - fluid prepolymer generated by the two - component reactor is filled into the product storage container (70) through the discharge port (60). When the filling liquid reaches near the upper part of the container, the upper part is heat - sealed (62), etc. The lower product discharge port (63) of the figure is closed from the beginning. In use, it is opened for discharge and moisture - cured to obtain the product. By using this device, room - temperature one - component products can be continuously and economically produced with inexpensive equipment. Also, for product use, at around 25°C (viscosity below 1,000,000 mPa / s), it is possible even manually (hand - pressure), and since it has excellent initial adhesion - to - fixation properties, it is useful as a household product (see Example 2; Table 2).

[0045] See Figure 2

[0046] Example 4. Conceptual diagram of the reactor (a) Reactor structure - water - cooled type (2A); An example of this method is shown in FIG. 2. It consists of a reactor main body (2A10), a reactor upper cover (2A11), a stirrer (2A12), a seal part (2A15), inlets for agent A and agent B (2A16, - 17), a discharge port (2A18), a water - cooling structure part (2A13), and a heat - insulating part (2A14). The water - cooling part / heat - insulating part (integrated) can be easily inserted and removed from the reactor main body. When the reaction heat of the two components is excessive, the main body is cooled and temperature - controlled for use. The cooling part has a structure where metal fine tubes (pipes) are wound around the main body through a heat - resistant film (such as Teflon (registered trademark)). Also, for temperature control, the actual temperature is measured by thermography and automatically controlled by a computer. (b) Reactor heating method (2B); Basically, it has a similar structure to the water - cooled type and is used complementarily when the reaction heat is insufficient and a predetermined reaction temperature and time cannot be maintained. The heating method is integrated with the silicon rubber and the heat - insulating part and can be inserted and removed from the main body for use, but it is not limited to this. Assume a dynamic mechanical stirring method (stepping motor method) for the stirring method. The reason for adopting the dynamic method is that it is easy to process the device, is suitable for various reaction liquids (viscosity, structural viscosity, etc.), and is easy to maintain, making it appropriate as the device for the manufacturing method of the present invention. (d) Reactor design / simulation; (2C); Since the purpose is to manufacture small-lot and multi-variety products, the reactor capacity is not specified at the current stage. Currently, the internal volume is assumed to be ≒ 3 - 10 ml, and the continuous discharge volume per minute (about 30 ml / min maximum) is assumed. The main body uses metals (SUS, brass, copper, aluminum, etc.), and the thickness of the main body (assumed to be ≒ 5 mm), discharge volume (raw material feed volume) - heat generation amount, specific heat of the raw material, heat capacity of the metal (specific heat, specific gravity, mass), etc. are optimized through computer simulation processing, etc., and 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 - 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 were considered. From the results in Table 3, the present invention (a) is considered to be superior to the current one-component RHM, particularly in terms of energy conservation, operability of the adhesive type RHM, and economy. Also, it is expected to be comparable in terms of performance. (b) is excellent in short-term fixing property compared to the current room-temperature two-component mixed type, and the present invention has shown that it improves the weaknesses of the mixed type (slow fixing property and operability (gelation in the mixer)). (c) Furthermore, the present invention newly shows that the advantages of the continuous manufacturing method of the moisture-curing type one-component product and the one-component product can be produced by the same technology as the two-component type of the present invention. Moreover, since the one-component product has a low fixing temperature near room temperature, the result that it can become a room-temperature one-component moisture-curing type (adhesive type - adhesive type) product was obtained. (d) Furthermore, the room temperature single-component moisture-curing product has a fast moisture-curing speed, and since polyurethane has a high cohesive force in terms of its molecular structure, it is expected to be excellent in terms of strength (flexibility, toughness, tear strength). Although not partially described in the table, in the future, the current single-component moisture-curing product (modified silicone product) that may be in a competitive relationship has a weak cohesive force and an initial fixing strength of about 5 to 10 minutes. Therefore, it is considered that it can develop as a new material to complement the current single-component product and the current single-component moisture-curing RHM. Based on the above, it is considered that the advancement, usefulness, etc. of the present invention are understood.

Brief Description of the Drawings

[0049]

Figure 1

Figure 2

Explanation of Reference Numerals

[0050] 10 Storage Container (Agent A) 20 Ibid. (Agent B) 11 Raw Material Storage Container (Agent A) 21 Ibid. (Agent B) 31 Gear Pump (Agent A) 32 Ibid.; Agent B 41 Switching Valve (Agent A) 42 Ibid. (Agent B) 50 Reactor 60 Discharge Section 70 Product Storage Container (Single-Component Type) 63 Single-Component Moisture-Curing Product 62 Ibid. (Product Discharge Port) 2A10 Reactor Body 2A11 Reactor Upper Cover 2A12 Stirrer 2A13 Water Cooling Pipe (Cooling Section) 2A14 Heat 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 moisture-curable polyurethane prepolymer using an apparatus for simultaneously producing a prepolymer and discharging / coating the prepolymer, comprising: (i) liquid A mainly containing a diisocyanate having a viscosity of 5 to 100,000 mPa·s at 25°C; and liquid B mainly containing a diol having a viscosity of 50 to 50,000 mPa·s at 25°C; (ii) the two liquids are supplied to a reactor in an anhydrous state under heating while the desired reaction ratio (NCO / OH group ratio) of the two liquids is constantly maintained within a range of 1±0.03, and the NCO / OH group ratio is constantly maintained. A method for producing a moisture-curable polyurethane prepolymer (excluding those containing a foam inhibitor), characterized in that a prepolymer obtained by reacting at an H group ratio of 1.3 / 1 to 2 / 1 (excluding 2 / 1), a reaction temperature of 60 to 170°C, and a reaction time of 2 to 60 seconds exhibits fluidity at the heating temperature and high adhesion to stickiness at 25°C, and (iii) the vapor pressure at 80°C of the prepolymer obtained by discharging from a discharge port at the bottom of the reactor does not exceed 1 mPa, and the prepolymer is excellent in safety, short-time sticking property, and moisture curing property at room temperature.

2. The content of the diisocyanate is 70 to 100% by mass based on the total polyisocyanate, and the content of the diol is 70 to 100% by mass based on the total polyol.

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