CN113773786B - A kind of polyurethane blend composition - Google Patents

Abstract

The invention discloses a polyurethane blend composition and a preparation method thereof. The polyurethane blend composition is prepared from raw materials containing a component A and a component B, wherein the component A is polyurethane containing polycarbonate diol; the component B is an acrylate copolymer containing methyl methacrylate and N, N-dimethylacrylamide. The polyurethane blend composition prepared by the invention has good compatibility and good high-temperature resistance.

Description

A kind of polyurethane blend composition

technical field

The invention belongs to the field of binder compositions, in particular to a polyurethane blend composition.

Background technique

Due to its unique molecular structure, polyurethane is widely used in various bonding fields, and has good flexibility, low temperature performance, and excellent cushioning and shock absorption functions. However, at higher temperatures (such as >=80°C), the hydrogen bonds between polyurethane molecules are significantly weakened, resulting in a significant decrease in the mechanical strength of polyurethane materials.

Blending modification is one of the effective methods to improve the high temperature resistance of polyurethane. The Chinese patent with the patent number CN110205081A discloses a two-component adhesive containing modified polyurethane acrylate resin. High temperature resistant fillers are added to the system to improve the high temperature resistance and ring test performance of the adhesive layer; the publication number is US6887917B The U.S. patent discloses a preparation method of UV-curable pressure-sensitive adhesive with good heat and moisture resistance. The system is polyacrylate (such as a copolymer of isooctyl acrylate and acrylic acid), monoacrylate functionalized low Polymer, PUA oligomer (and photoinitiator as components, prepared by blending, after curing, the adhesive film can form a semi-interpenetrating network, with high peel strength (> 40N/dm), and good heat resistance and moisture resistance.

In addition, it can also be modified by grafting. The Chinese patent No. CN106947053A reports a preparation method of epoxy resin modified polyurethane acrylate adhesive. This method makes polyurethane It reacts with acrylate and epoxy resin, and the prepared modified polyurethane acrylate adhesive has excellent heat resistance and bonding performance.

Due to its unique flexibility, low temperature and shock absorption, polyurethane is also playing more applications in optical displays. For materials used in optical displays, high light transmittance (average light transmittance >90% in the range of visible light 400nm-800nm) is often an important condition that must be met. Therefore, the use of blending modification to improve the mechanical properties of polyurethane needs to consider the compatibility of the blend system, because incompatible systems often lead to large phase separation, which will bring about a significant decrease in the light transmittance of the blend , the haze increases, making the blend unsuitable for applications requiring high light transmittance.

There are few literature reports on transparent polyurethane blends. US Patent No. US9790405B2 discloses a UV-curable polyurethane blend for optical display. The system includes a mixture of polyurethane and polyphenolic oxygen resin composed of polycarbonate diol. It is a solid adhesive film when used. It is used for the assembly of display modules, and after assembly, it is cured by ultraviolet light.

In order to make polyurethane's high flexibility, low temperature performance, and excellent shock absorption function play more roles in an increasing number of optical display devices, it is necessary to study more high-performance polyurethane blends.

Contents of the invention

A common problem in polymer blending is adjusting the compatibility between different materials. Incompatible systems will cause large-scale phase separation, resulting in decreased light transmittance and increased haze of the blend composition. In view of the problem of low light transmittance of the polyurethane material prepared by the blending method in the prior art, the primary purpose of the present invention is to provide a polyurethane blending composition.

In order to achieve the above object, the present invention adopts the following technical solutions to realize:

A polyurethane blend composition, prepared from raw materials comprising component A and component B, wherein component A is polyurethane comprising polycarbonate diol; component B is comprising methyl methacrylate Acrylate copolymer with N, N-dimethylacrylamide.

Preferably, the mass ratio of methyl methacrylate and N,N-dimethylacrylamide in the B component is 8:2˜2:8.

Preferably, the mass fraction of the acrylate copolymer of methyl methacrylate and N,N-dimethylacrylamide in component B in the polyurethane blend composition is x, and 10%≤x≤50%.

Preferably, the polyurethane of the polycarbonate diol described in component A is photocurable polyurethane acrylate.

Preferably, the polyurethane blend composition further includes a photoinitiator for initiating free radical polymerization.

Preferably, the average light transmittance of the polyurethane blend composition in the range of 400nm-800nm is >90%.

Preferably, the preparation method of the photocured polyurethane acrylate comprises the following steps: using polycarbonate diol as oligomer polyol, aliphatic diisocyanate as polyisocyanate, and small molecule diol as chain extender , using monohydroxyl (meth)acrylate as an end-capping agent to synthesize photocurable polyurethane acrylate.

Preferably, the specific implementation method of the preparation method of the photocured polyurethane acrylate is: adding an organic solvent to the polycarbonate diol, and then adding an aliphatic diisocyanate, controlling the temperature of the system to not exceed 75-85°C, Add the catalyst drop by drop. After the catalyst is added and the temperature stops rising, raise the temperature to 79-81°C; titrate the content of the remaining isocyanate NCO in the titration reaction. When the viscosity increases, add an organic solvent to measure the content of the remaining isocyanate NCO in the reaction. After the result is stable, first pass into dry air, then add a polymerization inhibitor and monohydroxyl (meth)acrylate, and use a Fourier transform infrared spectrometer to track the reaction. After the infrared characteristic peak of -NCO disappeared, the reaction was stopped, and the product was kept away from light.

Preferably, the molar ratio of the aliphatic diisocyanate: polycarbonate diol: small molecule diol: monohydroxyl (meth)acrylate is 2: 0.8-1.8: 0.1-1: 0.2-0.8;

The mass of the catalyst accounts for 0.05 to 0.1 wt% of the polycarbonate diol;

The mass of the polymerization inhibitor accounts for 0.05 to 0.1 wt% of the total mass of all synthetic monomers, and the monomers are aliphatic diisocyanate, polycarbonate diol, small molecule diol and monohydroxyl (meth)acrylic acid ester;

The aliphatic diisocyanate is hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane dimethylene One or more of diisocyanate, m-phenylene diisocyanate, and tetramethylxylylene diisocyanate;

The catalyst is one or both of dibutyltin dilaurate and stannous octoate;

The small molecule glycol is methylpropanediol, neopentyl glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, hexanediol, One or both of 1,4-cyclohexanedimethanol;

The two organic solvents are acetone, one or both of methyl ethyl ketone and ethyl acetate;

The polymerization inhibitor is one or both of 2,6-di-tert-butyl-p-cresol and 4-methoxyphenol;

Described monohydroxyl (meth) acrylate is -2-hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, in hydroxypropyl methacrylate one or two.

Preferably, the preparation method of the acrylate copolymer of methyl methacrylate and N,N-dimethylacrylamide described in component B comprises the following steps: taking methyl methacrylate, N,N-dimethyl Acrylamide is used as a polymerization monomer, adding a chain transfer agent and a chain initiator, and finally adding an organic solvent, after blowing nitrogen, raising the temperature to 60-80°C, and reacting for 18-24 hours, finally adding an organic solvent, and the system After dilution, the product was stored.

Preferably, the mass of the chain transfer agent accounts for 0.1-2.0 wt% of the total amount of methyl methacrylate and N,N-dimethylacrylamide;

The added amount of the chain initiator accounts for 0.1 to 1.0 wt% of the total amount of methyl methacrylate and N,N-dimethylacrylamide;

The chain initiator is one or more of azobisisovaleronitrile and azobisisoheptanonitrile;

The chain transfer agent is one or more of dodecyl mercaptan, isooctyl thioglycolate, isooctyl 3-mercaptopropionate, 2-mercaptoethanol, and 3-mercaptopropionic acid;

The organic solvent is one or both of acetone, methyl ethyl ketone and ethyl acetate.

Mechanism of the present invention is:

When the polyacrylate contains methyl methacrylate and N,N-dimethylacrylamide, the polyacrylate can form a high light transmittance blend system with polycarbonate polyurethane acrylate. At the same time, due to the good compatibility, the obtained blend composition can improve the mechanical strength of the urethane acrylate material (such as the adhesion to the substrate).

Compared with the prior art, the present invention has the following advantages and beneficial effects:

The polyurethane blend composition prepared by the present invention has good compatibility (shown in the high light transmittance of the blend in the visible light range), and at the same time, its high temperature resistance is good, and the high temperature (70 ° C) peeling force is as high as 5.6 (N/25mm), high temperature (70 ℃) stickiness greater than 10000min.

detailed description

The present invention will be further described below in conjunction with specific examples, but the implementation examples do not limit the present invention in any way. Unless otherwise specified, the following reagents, methods and equipment are commonly used reagents, methods and equipment in the field of synthesis and processing.

Unless otherwise specified, all reagent materials used in the present invention are commercially available, wherein the polycarbonate diol has a molecular weight of 1000.

Example 1

A kind of preparation method of polyurethane blend composition, its preparation steps are as follows:

(1) Pour 50.00 g of polycarbonate diol into a 500 ml four-necked reaction flask connected with a mechanical stirrer, a condenser tube, a sample inlet and a temperature probe, dehydrate under vacuum at 110°C for 2 hours, cool down to 60°C, and After ten minutes of nitrogen purge, 30.66 g of methyl ethyl ketone (MEK) was added, followed by 8.41 g of hexamethylene diisocyanate (HDI) and 13.12 g of 4,4'-dicyclohexylmethane diisocyanate (HMDI), and Slowly add 0.025 g of dibutyltin dilaurate (DBTDL) dropwise, and control the temperature of the system not to exceed 80°C. After the catalyst was added dropwise and the temperature stopped rising, the temperature was raised to 80°C. The "di-n-butylamine method" was used to titrate the content of the remaining isocyanate NCO in the reaction. When the titration result becomes stable, slowly add 3.60 g of 1,4-butanediol (BD), and add 40.00 g of MEK when the viscosity of the system increases. Also use the "di-n-butylamine method" to track the reaction. After the result is stable, first pass through dry air for 5 minutes, then add 0.038 grams of 2,6-di-tert-butyl-p-cresol (BHT) and 1.18 grams of acrylic acid-2- Hydroxyethyl ester (HEA), use Fourier transform infrared spectrometer to track the reaction, after the infrared characteristic peak (2270cm ^-1 -2280cm ^-1 ) of -NCO disappears, stop the reaction, pour the product into a reagent bottle and store it in the dark, that is, it is prepared Polyurethane acrylate;

(2) Take 5 grams of methyl methacrylate (MMA), 5 grams of N,N-dimethylacrylamide (NNDMA) as polymerized monomers, 0.05 grams of 2-mercaptoethanol as a chain transfer agent, 0.0352 grams of azobis Isovaleronitrile (AMBN) as a chain initiator was added in batches to a 500 ml flask, followed by 5.93 g of MEK. After passing nitrogen for 10 minutes, raise the temperature to 65°C, react for 24 hours, and finally add 9.07 grams of MEK, after diluting the system, pour the product into a reagent bottle for storage, and then prepare polyacrylate;

(3) After mixing the urethane acrylate described in step (1) and the polyacrylate described in step (2) according to a mass ratio of 9:1, add 1% by weight of the total mass of urethane acrylate and polyacrylate Initiator Irgacure184, after mixing evenly, is poured on the self-made coating machine that is covered with polyethylene terephthalate (PET) film or the PET release film (thickness is 50 microns) that the surface is coated with silicone resin, regulates The distance between the scraper and the bottom plate, pull the PET film slowly and uniformly, so that the solution passes through the scraper to form a film with uniform thickness, and then put it in an 80°C blast drying oven to dry for 10 minutes, and then apply a layer of release film ( Thickness 50 microns) is coated on the adhesive film surface, obtains the polyurethane blend composition that adhesive film thickness is 25 microns.

Example 2

A kind of preparation method of polyurethane blend composition, its preparation steps are as follows:

(1) with embodiment 1;

(2) with embodiment 1;

(3) After mixing the urethane acrylate described in step (1) and the polyacrylate described in step (2) according to a mass ratio of 8:2, the rest of the operations are the same as in Example 1.

Comparative example 1

A kind of preparation method of polyurethane acrylate, its preparation step is as follows:

(1) with embodiment 1;

(2) The polyurethane acrylate prepared in step (1) is added with Irgacure184 accounting for 1 wt% of its mass, mixed evenly, and poured on a self-made coating machine covered with PET film or PET release film (both thickness is 50 microns) , adjust the distance between the scraper and the bottom plate, slowly pull the PET film at a uniform speed, let the solution pass through the scraper to form a film with uniform thickness, and then put it in an 80°C blast drying oven to dry for 10 minutes, and then release a layer The film (thickness 50 microns) is coated on the surface of the adhesive film to obtain a polyurethane acrylate adhesive film with an adhesive film thickness of 25 microns.

Comparative example 2

A kind of preparation method of polyurethane acrylate, its preparation step is as follows:

(1) with embodiment 1;

(2) Take 9 grams of methyl methacrylate (MMA) and 1 gram of N,N-dimethylacrylamide (NNDMA) as polymerized monomers, and other operations are the same as in Example 1;

(3) with embodiment 1.

Comparative example 3

A kind of preparation method of polyurethane acrylate, its preparation step is as follows:

(1) with embodiment 1;

(2) Take 1 gram of methyl methacrylate (MMA) and 9 grams of N,N-dimethylacrylamide (NNDMA) as polymerized monomers, and other operations are the same as in Example 1;

(3) with embodiment 1.

Related performance tests:

The products of Examples 1～2 and Comparative Examples 1～3 are tested as follows:

The light transmittance was tested by a UV-Vis spectrophotometer.

Normal temperature peel force, high temperature (70°C) peel force and high temperature (70°C) stickiness were tested by peel strength tester, constant temperature and humidity type peel strength tester and oven type tape retention tester respectively. The peel force test refers to the peel force test specification (executive standard GB 2792-1998), and the sticky test refers to the test method of adhesive tape stickiness (executive standard GB/T 4851-2014). The test results are shown in Table 1.

Table 1 Performance test list

It can be concluded from Table 1 that the normal temperature peeling force and high temperature (70°C) peeling force of PA (polyacrylate) modified PUA (polyurethane acrylate) have been significantly improved, and high temperature (70°C) stickiness The performance is still good, but when the PA content is 20%, the normal temperature peeling force of the system is lower than that of the PA content of 10%, and the high temperature peeling force is not much different, so the modification effect of PUA is better when the PA content is 10%.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (5)

1. A polyurethane blend composition is characterized by being prepared from raw materials containing a component A and a component B, wherein the component A is polyurethane containing polycarbonate diol; the component B is an acrylate copolymer containing methyl methacrylate and N, N-dimethylacrylamide;

the mass ratio of the methyl methacrylate to the N, N-dimethylacrylamide in the component B is 8:2-8, and the mass fraction of the acrylic ester copolymer of the methyl methacrylate and the N, N-dimethylacrylamide in the component B in the polyurethane blending composition is x, wherein x is more than or equal to 10% and less than or equal to 50%.

2. The polyurethane blend composition of claim 1, wherein the mass ratio of methyl methacrylate to N, N-dimethylacrylamide in component B is 1:1.

3. The polyurethane blend composition of claim 1, wherein the polyurethane of the polycarbonate diol in component a is a curable urethane acrylate.

4. A polyurethane blend composition according to any one of claims 1 to 3, wherein said polyurethane blend composition further comprises an initiator for initiating a free radical polymerization reaction.

5. A polyurethane blend composition according to any one of claims 1 to 3, wherein said polyurethane blend composition has an average light transmission >90% in the range of 400nm to 800 nm.