TW202239796A - Preparation method of anti-yellowing TPU master batch - Google Patents

Abstract

A preparation method of an anti-yellowing-TPU master batch comprises the following steps: step 1, carrying out water removal treatment on a reaction container, putting isocyanate and ethyl cyanoacrylate into the reaction container at the temperature of 40-60 DEG C, introducing nitrogen into the reaction container, and stirring to form a first prepolymer, wherein the molar mass of the ethyl cyanoacrylate is 1/2 of the molar mass of the isocyanate; step 2, putting the first prepolymer and macromolecular dihydric alcohol into a reaction container at the temperature of 60-80 DEG C, filling nitrogen into the reaction container, stirring, reacting for 50-70 minutes, and discharging to form a second prepolymer; and step 3, putting the second prepolymer, a chain extender, an antioxidant and a catalyst into a reaction container at the temperature of 60-80 DEG C, and stirring for 30-60 seconds to form the yellowing-resistant TPU master batch. According to the invention, the ethyl cyanoacrylate is adopted to replace the traditional ultraviolet light absorber and light stabilizer, the yellowing structure is directly changed by a chemical method, the physical property of the TPU master batch is not changed, and the problem that the TPU master batch cannot be uniformly dispersed is avoided.

Description

A kind of preparation method of anti-yellowing TPU masterbatch

The invention relates to a preparation method of TPU master batches, in particular to a preparation method of anti-yellowing TPU master batches.

With the progress of the times, people have higher and higher requirements for the quality of life. The quality of daily necessities and some industrial products has been greatly different from the past. Among them, the domestic demand for thermoplastic polyurethane (TPU) It also grows proportionally every year. At present, the annual domestic usage reaches hundreds of thousands of tons.

The main raw material of TPU isocyanate is divided into aromatic and aliphatic, and aliphatic has been unable to grow significantly due to the cost relationship and the problem of back-end processing performance, especially in mainstream injection molding and extrusion products. It has been unable to effectively improve, so aromatic TPU still occupies the absolute majority of the market.

Although aromatic TPU has absolute advantages in terms of comprehensive physical properties, there have always been problems in its yellowing performance. This is because after natural use, covalent structures such as anthraquinone and quinone imine catalysts will gradually form in the aromatic TPU. Alkyl groups between benzene rings), and under the influence of ultraviolet light, it will cause yellowing of aromatic TPU.

There are many anti-yellowing agents on the market to solve the yellowing of aromatic TPU. Among them, ultraviolet light absorbers (Aniti-UV) and light stabilizers (Stabilizer) are used more, which shield the effect of ultraviolet light on aromatic TPU by physical methods. influence, and all have good effects.

However, at present, there is a problem of whether the anti-yellowing agents on the market can be uniformly dispersed: the amount of yellowing agents added is mostly between 0.3 and 1.5%. During processing, they are dispersed in TPU in a low-viscosity fluid state, and TPU particles are still high-viscosity fluids during the heating process, and cannot be co-mixed with low-viscosity fluids, that is, heterogeneous mixing.

In view of this, our inventors are concentrating on further research, and embark on research and development and improvement, hoping to solve the above problems with a better invention, and the present invention comes out after continuous testing and modification.

The technical solution of the present invention is aimed at the above-mentioned situation, in order to solve the above-mentioned problem and provide a kind of preparation method of anti-yellowing TPU masterbatch, described preparation method comprises:

Step 1. The reaction vessel is subjected to water removal treatment, and the isohydrogen salt and ethyl cyanoacrylate are placed in a reaction vessel at a temperature of 40-60°C. 1/2, fill the reaction vessel with nitrogen and stir until the NCO value reaches 16.6, then unload to form the first prepolymer;

Step 2. Put the first prepolymer and high molecular diol into a reaction vessel with a temperature of 60-80°C, fill the reaction vessel with nitrogen and stir it, react for 50-70 minutes and unload it to form the second prepolymer;

Step 3. Put the second prepolymer, chain extender, antioxidant and catalyst into a reaction vessel at a temperature of 60-80°C, stir for 30-60s, and maintain the NCO value at 33.2 to form an anti-yellowing TPU masterbatch.

Further, in step 1, before putting the isohydrogen salt and ethyl cyanoacrylate into the reaction container, it also includes: dissolving the isohydrogen salt in an environment of 75-85° C. for 170-190 minutes.

Further, in step 1, the dewatering treatment specifically includes:

Step 1.1, preheating the reaction vessel, the preheating temperature is 120~140°C;

Step 1.2, vacuumize the reaction vessel, the pressure is 750mmHg, and maintain for 110~130min;

Step 1.3, cool down to 40~60°C.

Further, in step 1, the overall viscosity of the first prepolymer is 1000~2000CPS.

Further, in step 1, the isohydrogen salt is one or a mixture of diphenylmethane diisocyanate and toluene diisocyanate.

Further, in step 2, the polymer diol is AA/EG polymer diol, polymer polycaprolactone diol, polymer polycarbonate diol, polymer polyether PTMEG diol, high One or more of molecular polyether PPG diols and polymer polyether PEG diols are mixed.

Further, in step 3, the chain extender is one or a mixture of 1,4 butanediol and ethylene glycol.

Further, the antioxidant is one or more mixtures of antioxidant BHT, antioxidant 1010, antioxidant 1076 and antioxidant 168.

Further, the catalyst is a mixture of one or more of stannous octoate, amine catalyst, bismuth and antimony.

After adopting the above technical scheme, the effect of the present invention is: the present invention uses ethyl cyanoacrylate to replace the traditional ultraviolet light absorber and light stabilizer, directly chemically changes the structure that causes yellowing, and does not change the TPU masterbatch at the same time The physical properties avoid the problem of non-uniform dispersion.

Regarding the technical means of our inventors, several preferred embodiments will be described in detail below in conjunction with the drawings, so as to provide an in-depth understanding and recognition of the present invention.

Below by embodiment technical solution of the present invention is described further:

The invention provides a preparation method of anti-yellowing TPU masterbatch, the preparation method comprising:

Step 1. The reaction vessel is dewatered, and the isohydrogen salt (that is, an aromatic material containing isocyanate group) and ethyl cyanoacrylate are placed in a reaction vessel at a temperature of 40~60°C. The moles of ethyl cyanoacrylate The mass is 1/2 of the molar mass of the isohydrogen salt, and the reaction vessel is charged with nitrogen and stirred until the NCO value reaches 16.6, and then unloading is performed to form the first prepolymer;

Step 2. Put the first prepolymer and high molecular diol into a reaction vessel with a temperature of 60-80°C, fill the reaction vessel with nitrogen and stir it, react for 50-70 minutes and unload it to form the second prepolymer;

Step 3. Put the second prepolymer, chain extender, antioxidant and catalyst into a reaction vessel at a temperature of 60-80°C, stir for 30-60s, and maintain the NCO value at 33.2 to form an anti-yellowing TPU masterbatch.

The invention adopts ethyl cyanoacrylate to replace the traditional ultraviolet light absorber and light stabilizer, and directly chemically changes its yellowing structure without changing the physical properties of the TPU masterbatch, avoiding the problem of inability to uniformly disperse.

Among them, ethyl cyanoacrylate not only occupies the α position between the diphenyl rings of the isohydrogen salt, but also has unsaturated double bonds, so the diphenyl rings no longer have the ability to produce anthraquinone and quinone imine catalysts The condition of equal covalent structure avoids the influence of ultraviolet light on the material, so that the TPU masterbatch no longer changes color. In addition, although ethyl cyanoacrylate contains two unsaturated double bonds, it is not easy to lose electrons and accelerate aging because it is located in the middle of the biphenyl ring, forming a shielding effect and reducing its activity.

It is worth mentioning that the use of highly reducing raw materials such as NO, NO ₂ , SO ₂ and halogen elements can also achieve the effect of anti-yellowing, but the above-mentioned raw materials will cause environmental pollution, and the cyanide used in the present invention Ethyl acrylate can meet environmental protection requirements.

Wherein, isocyanate is highly sensitive to water, and ethyl cyanoacrylate is higher for water sensitivity, and dehydration treatment can avoid moisture to isocyanate and ethyl cyanoacrylate to reaction vessel. Influenced by low temperature and long time of slow reaction, ethyl cyanoacrylate is embedded in the α position between the biphenyl rings to obtain a stable structure. In addition, filling with nitrogen can block the moisture in the air.

Wherein, in step 1, since the molar mass of ethyl cyanoacrylate is 1/2 of the molar mass of isohydrogen salt, it is ensured that the alkyl group between the aromatic diphenyl rings can only be absorbed by the molar mass of ethyl cyanoacrylate. 3π bonds are substituted, so there is no excess unsaturated group reaction.

Among them, since the high molecular weight diol is first polymerized in step 2, and then the chain extender is added in step 3, the implosion phenomenon that may occur during chain extension can be avoided.

Among them, because the activity of isocyanate is very high, it is easy to self-polymerize in an environment with a temperature exceeding 70°C for a long time. Therefore, the present invention adopts a three-stage polymerization method to avoid the problem of self-polymerization: first in step 1 at a low temperature Under normal circumstances, half of the reaction is completed (NCO value reaches 16.6), and after the activity is reduced, the temperature is raised in step 2 so that it can complete the long-chain chain extension reaction with the hydroxyl group. In step 3, because the short chain participates in the chain extension and the catalyst is added, Its reaction is the most intense, so antioxidants are added to prevent the negative effect of thermal oxidation, so that the NCO value is maintained at 33.2, thereby completing the entire polymerization reaction under the premise of avoiding the self-polymerization of isocyanate.

Among them, since the reaction temperature adopted in the present invention is lower than the reaction temperature above 90°C required for polymerizing TPU in the traditional process, the overall energy consumption can be reduced.

Specifically, the reaction vessel used in the present invention is a reaction kettle.

Specifically, in step 1, before putting the isohydrogen salt and ethyl cyanoacrylate into the reaction container, it also includes: dissolving the isohydrogen salt in an environment of 75-85° C. for 170-190 minutes.

Specifically, in step 1, the water removal treatment specifically includes:

Step 1.1, preheating the reaction vessel, the preheating temperature is 120~140°C;

Step 1.2, vacuumize the reaction vessel, the pressure is 750mmHg, and maintain for 110~130min;

Step 1.3, cool down to 40~60°C.

Specifically, in step 1, the overall viscosity of the first prepolymer is 1000-2000 CPS. A viscosity of 1000~2000CPS can ensure the smooth formation of finished products.

Specifically, in step 1, the isohydrogen salt is one or a mixture of diphenylmethane diisocyanate (MDI) and toluene diisocyanate (TDI).

Specifically, in step 2, before putting the first prepolymer and the high molecular diol into the reaction vessel, it also includes: putting the high molecular diol in an environment of 115~125°C for 110~130min Dissolved, and then placed in a room temperature environment for cooling.

Specifically, in step 2, the polymer diol is AA/EG polymer diol, polymer polycaprolactone diol, polymer polycarbonate diol, polymer polyether PTMEG diol, One or more of the polymer polyether PPG diol and the polymer polyether PEG diol are mixed.

Specifically, in step 3, the chain extender is one or a mixture of 1,4 butanediol and ethylene glycol.

Specifically, in step 3, the antioxidant is one or more mixtures of antioxidant BHT, antioxidant 1010, antioxidant 1076 and antioxidant 168.

Specifically, in step 3, the catalyst is a mixture of one or more of stannous octoate, amine catalysts, bismuth and antimony.

[Example 1]

In this embodiment, the preparation method of anti-yellowing TPU masterbatch comprises:

Step 1. The reaction vessel is subjected to water removal treatment. At the same time, MDI is put into an environment of 80°C for 180 minutes to dissolve, and then 2.5kg of MDI and 0.6kg of ethyl cyanoacrylate are placed in a reaction vessel at a temperature of 50°C. Fill the reaction vessel with nitrogen and stir until the NCO value reaches 16.6, then unload to form the first prepolymer;

Step 2. Dissolve the AA/EG polymer diol in an environment of 120°C for 120 minutes, then place it in a normal temperature environment for cooling, then add 3.1kg of the first prepolymer and 6.9kg of AA/EG Put the polymer diol into a reaction vessel with a temperature of 70°C, fill the reaction vessel with nitrogen gas and stir, react for 60 minutes and unload to form the second prepolymer;

Step 3. Put 10kg of the second prepolymer, 0.6kg of 1,4-butanediol, 0.01kg of antioxidant BHT and 0.002kg of stannous octoate into a reaction vessel at a temperature of 70°C, stir for 40s, and maintain the NCO value At 33.2, form anti-yellowing TPU masterbatch.

[Example 2]

In the present embodiment, the preparation method is similar to that of Example 1, except that:

In step 1, put 3.9kg of MDI and 0.98kg of ethyl cyanoacrylate into a reaction vessel with a temperature of 50°C; in step 2, put 4.88kg of the first prepolymer and 4.5kg of AA/EG The polymer dihydric alcohol is placed in a reaction vessel with a temperature of 70°C; in step 3, 9.38kg of the second prepolymer, 1.6kg of 1,4 butanediol, 0.01kg of antioxidant BHT and 0.002kg of Put stannous octoate into a reaction vessel with a temperature of 70°C.

[Comparative Example 1]

In the present embodiment, the preparation method is similar to that of Example 1, except that:

In step 1, 4.5kg of MDI was placed in a reaction vessel at a temperature of 50°C (that is, no ethyl cyanoacrylate was added); in step 2, 4.5kg of the first prepolymer and 3.9kg of AA/ EG polymer diol is placed in a reaction vessel with a temperature of 70°C; in step 3, 8.4kg of the second prepolymer, 1.6kg of 1,4 butanediol, 0.01kg of antioxidant BHT and 0.002kg The stannous octoate is placed in a reaction vessel with a temperature of 70°C.

[Comparative example 2]

In the present embodiment, the preparation method is similar to that of Example 1, except that:

In step 1, 4.5kg of MDI was placed in a reaction vessel at a temperature of 50°C (that is, no ethyl cyanoacrylate was added); in step 2, 4.5kg of the first prepolymer and 3.9kg of AA/ EG macromolecular diol is put into a reaction vessel with a temperature of 70°C; 1,4 butanediol, 0.01kg of antioxidant BHT and 0.002kg of stannous octoate were placed in a reaction vessel at a temperature of 70°C.

The anti-yellowing TPU masterbatch prepared by the above-mentioned examples was tested for anti-yellowing, and 20 test pieces were prepared for each embodiment. Among them, the TPU masterbatch of Example 1 had 19 times of 4th grade of anti-yellowing grade. The standard value is 4 grades; the TPU masterbatch of embodiment 2 occurs 18 times of 4 grades of yellowing resistance grade, and its standard value is 4 grades; the TPU masterbatch of comparative example 1 occurs 17 times of 2.5 grades of yellowing resistance grade, 3 The standard value of the sub-3 yellowing resistance grade is 2.5; 20 times of the 4th yellowing resistance grade in Comparative Example 2, and its standard value is 4 grades. As a result, the test results are as follows [Table 1]:

[Table 1] Anti-yellowing grade Example 1 Example 2 Comparative example 1 Comparative example 2 2.5 √ 3 3.5 4 √ √ √

The above test results prove that the preparation method of the present invention can solve the problem of yellowing of the TPU masterbatch, and the finished product can reach level 4 yellowing resistance, and avoid the problem of inhomogeneous dispersion.

The above-described embodiments are only preferred examples of the present invention, and are not intended to limit the scope of the present invention, so all equivalent changes or modifications made according to the structure, features and principles described in the patent scope of the present invention should be Included in the patent application scope of the present invention.

To sum up, the technical means disclosed in the present invention can effectively solve the problems of conventional knowledge and achieve the expected purpose and effect, and it has not been published in publications before application, has not been publicly used, and has long-term progress. The invention mentioned in the patent law is correct. I file an application according to the law. I sincerely pray that Junshang Hui will give you a detailed review and grant the invention patent. I am very grateful to Dexin.

However, the above are only several preferred embodiments of the present invention, and should not limit the scope of the present invention, that is, all equivalent changes and modifications made according to the patent scope of the present invention and the content of the description of the invention are all Should still belong to the scope covered by the patent of the present invention.

〔this invention〕 none.

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Claims (9)

A kind of preparation method of anti-yellowing TPU masterbatch, it is characterized in that: described preparation method comprises: Step 1. The reaction vessel is subjected to water removal treatment, and the isohydrogen salt and ethyl cyanoacrylate are placed in a reaction vessel at a temperature of 40-60°C. 1/2, fill the reaction vessel with nitrogen and stir until the NCO value reaches 16.6, then unload to form the first prepolymer; Step 2. Put the first prepolymer and high molecular diol into a reaction vessel with a temperature of 60-80°C, fill the reaction vessel with nitrogen and stir it, react for 50-70 minutes and unload it to form the second prepolymer; Step 3. Put the second prepolymer, chain extender, antioxidant and catalyst into a reaction vessel at a temperature of 60-80°C, stir for 30-60s, and maintain the NCO value at 33.2 to form an anti-yellowing TPU masterbatch. The preparation method of the anti-yellowing TPU masterbatch as described in claim item 1, wherein, in step 1, before putting the isohydrogen salt and ethyl cyanoacrylate into the reaction container, it also includes: putting the isohydrogen salt in Put it into the environment of 75~85℃ for 170~190min to dissolve. The preparation method of the anti-yellowing TPU masterbatch as described in claim 1, wherein, in step 1, the water removal treatment specifically includes: Step 1.1, preheating the reaction vessel, the preheating temperature is 120~140°C; Step 1.2, vacuumize the reaction vessel, the pressure is 750mmHg, and maintain for 110~130min; Step 1.3, cool down to 40~60°C. The preparation method of anti-yellowing TPU masterbatch as described in Claim 1, wherein, in step 1, the overall viscosity of the first prepolymer is 1000~2000CPS. The preparation method of anti-yellowing TPU masterbatch as described in Claim 1, wherein, in step 1, the isohydrogen salt is one or a mixture of diphenylmethane diisocyanate and toluene diisocyanate. The preparation method of anti-yellowing TPU masterbatch as described in claim item 1, wherein, in step 2, polymer diol is AA/EG polymer diol, polymer polycaprolactone diol, high molecular weight polycaprolactone diol, One or more of molecular polycarbonate diol, high molecular polyether PTMEG diol, high molecular polyether PPG diol and high molecular polyether PEG diol are mixed. The preparation method of anti-yellowing TPU masterbatch as described in claim 1, wherein, in step 3, the chain extender is one or two kinds of mixtures of 1,4 butanediol and ethylene glycol. The preparation method of anti-yellowing TPU masterbatch according to claim 1, wherein the antioxidant is one or more of antioxidant BHT, antioxidant 1010, antioxidant 1076 and antioxidant 168 mixed. The preparation method of anti-yellowing TPU masterbatch as described in Claim 1, wherein the catalyst is one or more mixtures of stannous octoate, amine catalysts, bismuth and antimony.