Isocyanate composition, preparation method thereof and PVC (polyvinyl chloride) coating slurry

Abstract

The invention discloses an isocyanate composition, a preparation method thereof and PVC (polyvinyl chloride) coating slurry. The isocyanate composition is prepared from the following components in parts by mass: 15 to 50 parts of an isocyanate monomer, 0.1 to 2 parts of a bridging agent, 0.05 to 1.5 parts of a catalyst, 5 to 20 parts of a solvent, 40 to 70 parts of a plasticizer, 0.05 to 1 part of a stabilizer and 0.05 to 2 parts of a polymerization inhibitor. According to the isocyanate composition, the preparation method thereof and the PVC coating slurry provided by the invention, the bonding performance of the PVC slurry and synthetic fiber mesh cloth can be remarkably improved, and the product quality is remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of chemical materials, and relates to a composition, in particular to an isocyanate composition, a preparation method thereof and a PVC coating slurry. BACKGROUND

[0002] As a key raw material for the synthesis and application of polyurethane, isocyanate has been widely used in the fields of coatings and adhesives. However, due to the high volatility, high toxicity, poor heat resistance, weak adhesion and slow curing speed of conventional isocyanate monomers, they need to be modified before use. As common isocyanate monomers, toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI) have been developed into modified products on the market.

[0003] With the rapid development of the production capacity and variety types of PVC paste resins in China, the development and application of downstream products have also been rapidly developed. In the field of PVC coated fabrics, such as flame-retardant conveyor belts, light conveyor belts, high-grade waterproof cloth, coated tarpaulin and high-grade membrane structures, these coated fabric products are mostly composed of synthetic fiber mesh and PVC slurry, which significantly improves the tensile strength, tear strength and burst strength of PVC coated products. On the other hand, the synthetic fibers used in such fabric coating materials are mostly polyester and nylon. These chemical fiber materials have few reactive groups on the surface and weak anchoring ability. The adhesion of PVC paste resin slurry after direct coating, plasticizing and curing is weak, and the peel strength is low, which seriously affects the use and processing performance of fabric coating products. Therefore, how to obtain high peel strength of coated fabric products has become one of the important physical property indicators for distinguishing the market application and product quality of PVC fabric coating products.

[0004] Therefore, there is an urgent need to design a new PVC coating slurry to overcome at least some of the above-mentioned defects of existing PVC coating slurries. SUMMARY

[0005] The application provides an isocyanate composition, a preparation method thereof and a PVC coating slurry, which can significantly improve the adhesion and bonding performance of PVC slurry and synthetic fiber mesh, and significantly improve the product quality.

[0006] To solve the above technical problems, according to one aspect of the application, the following technical scheme is adopted: A preparation method of an isocyanate composition, the preparation method comprising: Step S1, into the reaction vessel is added mass fraction of 15~50 isocyanate monomer, mass fraction of 5~20 solvent, mass fraction of 40~70 plasticizer, mass fraction of 0.05~1.5 catalyst, mass fraction of 0.05~1 stabilizer, after feeding is completed, inert gas is passed in, stirring is started and heating is started, temperature is raised to 35~45 DEG C, reaction is carried out for a first set time; Step S2, continue to raise temperature to 70~80 DEG C, keep temperature and carry out reaction, after reaction is carried out for a second set time, test isocyanate group NCO content; Step S3, when isocyanate group NCO content reaches a first threshold value, reduce temperature to 40~50 DEG C, add mass fraction of 0.1~2 bridging agent, continue to keep temperature and carry out reaction, test isocyanate group NCO content; Step S4, when isocyanate group NCO content reaches a second threshold value, add polymerization inhibitor, continue to keep temperature and carry out reaction for a third set time, filter out material, seal and store; Wherein, the first threshold value is greater than or equal to 3.6%, less than or equal to 13%, the second threshold value is greater than or equal to 2.5%, less than or equal to 10%; the first threshold value is greater than or equal to the second threshold value.

[0007] As an embodiment of the application, in step S1, isocyanate monomer, solvent, plasticizer, catalyst and stabilizer are sequentially added into the reaction vessel; the inert gas passed in after feeding is completed is nitrogen; the reaction vessel is a reaction kettle, the reaction kettle is provided with a circulating condensing medium channel, a circulating condensing medium delivery switch is opened, and the circulating condensing medium is condensed water.

[0008] As an embodiment of the application, in step S1, the first set time is 1~1.5h; in step S2, the second set time is 3~4h; in step S4, the third set time is 0.5~1h.

[0009] According to another aspect of the application, the following technical scheme is adopted: an isocyanate composition prepared by the above preparation method, the isocyanate composition comprising: mass fraction of 15~50 isocyanate monomer, mass fraction of 0.1~2 bridging agent, mass fraction of 0.05~1.5 catalyst, mass fraction of 5~20 solvent, mass fraction of 40~70 plasticizer, mass fraction of 0.05~1 stabilizer, mass fraction of 0.05~2 polymerization inhibitor.

[0010] As an embodiment of the present application, the raw material composition of the isocyanate composition and the mass percentage of each raw material are as follows: isocyanate monomer 15-50%, bridging agent 0.1-2%, catalyst 0.05-1.5%, solvent 5-20%, plasticizer 40-70%, stabilizer 0.05-1%, and polymerization inhibitor 0.05-2%.

[0011] As an embodiment of the present application, the viscosity of the finished isocyanate composition is 5000-35000 mPa·s at an ambient temperature of 25°C, and the content of isocyanate groups NCO is 2.5%-10%.

[0012] As an embodiment of the present application, the isocyanate monomer includes at least one of 2,4-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

[0013] As an embodiment of the present application, the bridging agent includes at least one of trimethylolpropane, glycerol, pentaerythritol, and sorbitol.

[0014] As an embodiment of the present application, the catalyst includes at least one of lithium acetate, sodium acetate, potassium acetate, triethylenediamine, triethylamine, tri-n-butyl phosphine, tetra- (dimethylamino) methyl bisphenol A, dibutyl tin dilaurate, N, N-dimethylbenzylamine, and N, N-diethylbenzylamine.

[0015] According to another aspect of the present application, the following technical solution is adopted: a PVC coating slurry including the above-mentioned isocyanate composition.

[0016] The isocyanate composition, the preparation method thereof, and the PVC coating slurry provided by the present application can significantly improve the bonding performance of the PVC slurry and the synthetic fiber mesh fabric. The reason is that the synthetic fiber mesh fabric, such as polyester and nylon, usually has active functional groups on the surface of the fiber, such as hydroxyl, amine, and carboxyl. The isocyanate functional groups in the slurry are used to react with the active functional groups, and the effective control of the structure and composition of the isocyanate composition is used to achieve strong bonding between the slurry and the fiber mesh fabric, thereby significantly improving the product quality. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The flowchart of the preparation method of the isocyanate composition in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0019] For a further understanding of the present application, preferred embodiments thereof will be described in conjunction with examples, but it will be understood that the description is merely intended to illustrate the features and advantages of the present application, and is not intended to limit the scope of the claims.

[0020] The description of this part is only for several typical embodiments, and the present application is not limited to the scope described in the embodiments. The same or similar prior art means and some technical features in the embodiments are mutually replaced, which are within the description and protection scope of the present application.

[0021] Unless otherwise indicated, all parts and percentages expressed herein are based upon weight, and all tests and measurements are conducted using methods contemporary with the filing date of this application. To the extent that any patent, patent application, or publication is cited in this application, the same is hereby incorporated by reference in its entirety into this application, and the equivalent thereof is intended to be expressly incorporated by reference into this application, particularly with respect to the definitions of the terms used therein and the disclosure of synthetic techniques, product and process design, polymers, comonomers, initiators or catalysts, etc. If there is a conflict between the definitions of terms provided in this application and that of a particular document incorporated herein by reference, the terms as defined in this application control.

[0022] Numerical ranges are approximate and thus include endpoints unless otherwise indicated. Numerical ranges include all values from and including the lower and the upper values, in increments of one unit. For ranges including an element or component of less than one, those less than one are considered to be included within the range, for example, weights, bulk descriptions, such as molecular weight, melt index, and the like, specify a range including all values up to, including the end value. For ranges that are less than one, those less than one are considered to be included within the range, for example, 1.1, 1.5, and the like. For ranges that include less than one unit, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. For ranges that include less than about 10 (for example, 1 to 5), one unit is generally considered to be 0.1. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest and highest value enumerated, are to be considered to be expressly stated in this application. It should also be noted that the terms "first", "second", or the like, are used herein merely to distinguish one element from another, and are not intended to designate a particular order or sequence unless otherwise indicated by the context.

[0023] As used in connection with chemical compounds, the singular form "include," "comprise," and "have" is intended to encompass all isomeric forms, unless the context clearly indicates otherwise (e.g., "hexane" alone or in combination with other terms includes all isomeric forms of hexane). Additionally, the use of the terms "one," "an," or "the" to describe a noun also

[0024] The terms "comprising," "including," "containing," and variations thereof do not exclude any other components, steps or processes not expressly stated. To the extent that any of the terms "comprising," "including," or "having" are used in the detailed description and claims, such terms are intended to be inclusive in a manner similar to the term "comprising" as an open term with the same meaning, unless the context clearly indicates otherwise. The term "or" as used herein is intended to mean an inclusive "or" rather than an exclusive "or" unless the context clearly indicates otherwise. The term "includes" means "comprises" or is "consist of."

[0025] The sequence of steps in the various embodiments of the description is merely illustrative of the implementation of the present application and the implementation of the present application is not limited by the sequence of steps.

[0026] The present application further discloses a preparation method of the isocyanate composition, Figure 1 The flow chart of the preparation method of the isocyanate composition in an embodiment of the present application is shown in the figure; Figure 1 The preparation method comprises the following steps:

Step S1

[0027] In an embodiment of the present application, in the step S1, the isocyanate monomers, the solvent, the plasticizer, the catalyst, and the stabilizer are sequentially added into the reaction vessel; the inert gas introduced after the completion of the feeding is nitrogen; the reaction vessel is a reaction kettle, the reaction kettle is provided with a circulating condensing medium channel, the delivery switch of the circulating condensing medium is opened, and the circulating condensing medium is condensate water.

[0028]

Step S2

[0029]

Step S3

[0030]

Step S4

[0031] The first threshold value is greater than or equal to 3.6% and less than or equal to 13%, the second threshold value is greater than or equal to 2.5% and less than or equal to 10%, and the first threshold value is greater than or equal to the second threshold value. In an embodiment, the first threshold value is 3.6% and the second threshold value is 2.5%; in another embodiment, the first threshold value is 8% and the second threshold value is 6%; and in yet another embodiment, the first threshold value is 13% and the second threshold value is 10%.

[0032] The application further discloses an isocyanate composition prepared by the preparation method, which comprises: 15~50 mass fraction of isocyanate monomers, 0.1~2 mass fraction of a bridging agent, 0.05~1.5 mass fraction of a catalyst, 5~20 mass fraction of a solvent, 40~70 mass fraction of a plasticizer, 0.05~1 mass fraction of a stabilizer, and 0.05~2 mass fraction of a polymerization inhibitor.

[0033] In an embodiment of the application, the raw material composition of the isocyanate composition and the mass percentage of each raw material are as follows: 15~50% of isocyanate monomers, 0.1~2% of a bridging agent, 0.05~1.5% of a catalyst, 5~20% of a solvent, 40~70% of a plasticizer, 0.05~1% of a stabilizer, and 0.05~2% of a polymerization inhibitor.

[0034] In an embodiment, the viscosity of the finished isocyanate composition is 5000~35000 mPa·s at an ambient temperature of 25℃, and the isocyanate group NCO content is 2.5%~10%.

[0035] In an embodiment of the application, the isocyanate monomers comprise at least one of 2,4-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

[0036] The bridging agent comprises at least one of trimethylolpropane, glycerol, pentaerythritol, and sorbitol. The catalyst comprises at least one of lithium acetate, sodium acetate, potassium acetate, triethylenediamine, triethylamine, tri-n-butyl phosphine, tetra- (dimethylamino) methyl bisphenol A, dibutyl tin dilaurate, N, N-dimethylbenzylamine, and N, N-diethylbenzylamine.

[0037] In an embodiment of the present application, the isocyanate composition comprises isocyanate monomer with a mass fraction of 15, bridging agent with a mass fraction of 0.1, catalyst with a mass fraction of 0.05, solvent with a mass fraction of 5, plasticizer with a mass fraction of 40, stabilizer with a mass fraction of 0.05, and polymerization inhibitor with a mass fraction of 0.05.

[0038] In an embodiment of the present application, the isocyanate composition comprises isocyanate monomer with a mass fraction of 50, bridging agent with a mass fraction of 2, catalyst with a mass fraction of 1.5, solvent with a mass fraction of 20, plasticizer with a mass fraction of 70, stabilizer with a mass fraction of 1, and polymerization inhibitor with a mass fraction of 2.

[0039] In an embodiment of the present application, the isocyanate composition comprises isocyanate monomer with a mass fraction of 30, bridging agent with a mass fraction of 1, catalyst with a mass fraction of 1, solvent with a mass fraction of 10, plasticizer with a mass fraction of 50, stabilizer with a mass fraction of 0.5, and polymerization inhibitor with a mass fraction of 1.

[0040] In a use scenario of the present application, the preparation process of the isocyanate composition is carried out according to the above-mentioned implementation steps, the formula (mass fraction) of each component raw material is shown in Table 1, the formula (mass fraction) of the PVC plastic paste slurry is shown in Table 2, and the application performance test results are shown in Table 3.

[0041] Table 1: Data table of isocyanate composition synthesis formula Raw material name Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 2,4-toluene diisocyanate 20 20 25 20 isophorone diisocyanate 20 20 hexamethylene diisocyanate 20 20 trimethylolpropane 0.5 glycerin 0.5 pentaerythritol 0.8 0.5 sorbitol 0.5 potassium acetate 0.5 0.5 0.5 dibutyltin dilaurate 0.5 0.5 butyl acetate 10 15 15 10 10 10 10 10 dibutyl phthalate 70 65 65 70 70 70 70 70 2,6-di-tert-butyl-p-cresol 1 1 1 1 1 methyl-p-toluenesulfonate 0.3 0.5 0.5 0.3 0.3 Note: The isocyanate compositions prepared in Examples 1-3 above are prepared according to the synthesis process disclosed in the present application, and Comparative Examples 1-3 are only room temperature compounded mixtures.

[0042] Table 2: Data table of PVC plastic paste implementation formula Raw material name Addition amount PVC paste resin 60 diisononyl phthalate 50 zinc-barium stabilizer 1.5 calcium carbonate 30 Table 3: Data table of application performance test results Performance test Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 b ]] viscosity a / mPa·s 15720 30357 32756 17307 27955 102 99 101 - Open time / min 165 90 75 150 105 225 270 255 ＞300 Peeling strength / (N / 5cm) 105.3 137.6 143.2 102.6 128.7 81.2 73.1 75.7 55.3 Note: a: Viscosity test: refer to GBT 2794-2022; b: Comparative Example 4 is a blank PVC plastic paste system without isocyanate composition.

[0043] In an embodiment of the present application, the prepared isocyanate composition is subjected to peel strength evaluation: the isocyanate composition of the present application or the comparative example is added to PVC plasticizing paste (material temperature 25℃), the isocyanate composition is added in an amount of 5%, after the isocyanate composition is stirred and mixed uniformly, the mixture is uniformly coated on a 1000dtexx1000dtex, woven density 20x20 root / inch polyester industrial silk woven fabric using a scraper, the coating weight per square is controlled at 250g±5g, and is placed in an oven at 200℃ for plasticization, the plasticization time is 90s. After the plasticization is completed, it is cooled to room temperature, cut into 5cmx20cm sample blocks, the above sample blocks are welded and fused two by two using a high-frequency welding machine, and then a peel strength tester is used for peel strength test, the tensile speed is 200mm / min.

[0044] In an embodiment of the present application, the prepared isocyanate composition is subjected to open time test: the isocyanate composition of the present application or the comparative example is added to PVC plasticizing paste (material temperature 25℃), the isocyanate composition is added in an amount of 5%, after the isocyanate composition is stirred and mixed uniformly, the viscosity of the mixture is tracked and tested every 15min using a rotary viscometer, and the time corresponding to the viscosity reaching 20000mPa.s is recorded.

[0045] The present application further discloses a PVC coating slurry, which comprises the above isocyanate composition.

[0046] In summary, the isocyanate composition, the preparation method thereof and the PVC coating slurry can significantly improve the bonding performance of the PVC slurry and the synthetic fiber mesh fabric. The reason is that the synthetic fiber mesh fabric, such as polyester and nylon, usually has active functional groups on the surface of the fiber, such as hydroxyl, amine and carboxyl, the isocyanate functional groups in the slurry are used to react with the active functional groups, and the effective control of the structure and composition of the isocyanate composition realizes the strong bonding between the slurry and the fiber mesh fabric, thereby significantly improving the product quality.

[0047] The technical features of the above-described embodiments can be combined arbitrarily, and in order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0048] The description and applications of the present application are illustrative, and not intended to limit the scope of the present application. The effects or advantages of the embodiments can not be achieved in the embodiments due to various factors, and the description of the effects or advantages is not intended to limit the embodiments. Variations and modifications of the embodiments disclosed herein can be made based on the description and drawings of the embodiments, and it is known that various elements and components of the embodiments can be substituted with other elements and components of similar function. It will be apparent to those skilled in the art that the present application can be embodied in other specific forms, structures, arrangements, proportions, and with other components, materials, and elements, without departing from the spirit or essential characteristics of the present application. Other variations and modifications of the embodiments disclosed herein can be made based on the description and drawings of the embodiments without departing from the scope and spirit of the application.

Claims

1. A method for preparing an isocyanate composition, characterized in that: The preparation method comprises: Step S1, adding 15-50 parts by weight of an isocyanate monomer, 5-20 parts by weight of a solvent, 40-70 parts by weight of a plasticizer, 0.05-1.5 parts by weight of a catalyst, and 0.05-1 parts by weight of a stabilizer to a reaction vessel, introducing an inert gas after the addition is completed, stirring and heating, raising the temperature to 35-45° C. and reacting for a first set time; Step S2, continue heating to 70-80°C, keep warm for reaction, and start tracking and testing the NCO content of isocyanate groups after the second set reaction time; Step S3: When the NCO content of the isocyanate group reaches a first threshold, the temperature is lowered to 40-50° C., 0.1-2 parts by weight of a bridging agent is added, the reaction is continued at the temperature, and the NCO content of the isocyanate group is tracked and tested; Step S4: When the NCO content of the isocyanate group reaches the second threshold, adding a polymerization inhibitor, continuing the heat-keeping reaction for a third set time, filtering the material, and sealing and storing; Among them, the first threshold is greater than or equal to 3.6% and less than or equal to 13%, the second threshold is greater than or equal to 2.5% and less than or equal to 10%; the first threshold is greater than or equal to the second threshold.

2. The preparation method according to claim 1, wherein: In step S1, isocyanate monomer, solvent, plasticizer, catalyst, and stabilizer are added to the reaction container in sequence; the inert gas introduced after the addition is nitrogen; the reaction container is a reactor, and the reactor is provided with a circulating condensing medium channel, and the delivery switch of the circulating condensing medium is opened, and the circulating condensing medium is condensed water.

3. The preparation method according to claim 1, wherein: In step S1, the first set time is 1 to 1.5 hours; in step S2, the second set time is 3 to 4 hours; and in step S4, the third set time is 0.5 to 1 hour.

4. An isocyanate composition prepared by the preparation method according to any one of claims 1 to 3, characterized in that: The isocyanate composition comprises: 15 to 50 parts by mass of an isocyanate monomer, 0.1 to 2 parts by mass of a bridging agent, 0.05 to 1.5 parts by mass of a catalyst, 5 to 20 parts by mass of a solvent, 40 to 70 parts by mass of a plasticizer, 0.05 to 1 parts by mass of a stabilizer, and 0.05 to 2 parts by mass of a polymerization inhibitor.

5. The isocyanate composition according to claim 4, wherein: The raw material composition of the isocyanate composition and the mass percentages of the individual raw materials are: 15-50% of isocyanate monomer, 0.1-2% of bridging agent, 0.05-1.5% of catalyst, 5-20% of solvent, 40-70% of plasticizer, 0.05-1% of stabilizer, and 0.05-2% of polymerization inhibitor.

6. The isocyanate composition according to claim 4, wherein: The finished isocyanate composition has a viscosity of 5000-35000 mPa·s at an ambient temperature of 25° C. and an NCO content of 2.5%-10%.

7. The isocyanate composition according to claim 4, wherein: The isocyanate monomer includes at least one of 2,4-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

8. The isocyanate composition according to claim 4, wherein: The bridging agent includes at least one of trimethylolpropane, glycerol, pentaerythritol and sorbitol.

9. The isocyanate composition according to claim 4, wherein: The catalyst includes at least one of lithium acetate, sodium acetate, potassium acetate, triethylenediamine, triethylamine, tri-n-butylphosphine, tetrakis-(dimethylamino)methylbisphenol A, dibutyltin dilaurate, N,N-dimethylbenzylamine, and N,N-diethylbenzylamine.

10. A PVC coating slurry, characterized in that: The PVC coating slurry comprises the isocyanate composition according to any one of claims 4 to 9.

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