CN117946581A - One-component polyurethane primer and adhesive tape using the same - Google Patents

Abstract

The invention provides a single-component polyurethane primer, which is prepared from the following raw materials: the alcohol material comprises polyester polyol, wherein the polyester polyol comprises at least one of polyethylene glycol adipate butanediol polyol, polyethylene glycol adipate diethylene glycol polyol and poly (3-methyl-1, 5-pentanediol adipate) polyol; the isocyanate material comprises diisocyanate and polyisocyanate, wherein the molecular structure of the diisocyanate and/or polyisocyanate comprises aromatic rings, and the mass ratio of the diisocyanate is as follows: polyisocyanate=6 to 12:1 to 5; auxiliaries, wherein the auxiliaries comprise a catalyst; a solvent; and the alcohol materials are calculated according to the mass ratio: isocyanate material=1 to 2:0.7 to 1.7. The single-component polyurethane primer can form a primer layer which has high surface tension, is resistant to solvents and is not easy to be corroded by the solvents in the adhesive layer, and can improve the surface tension of a base material.

Description

One-component polyurethane primer and adhesive tape using the same

Technical Field

The invention belongs to the technical field of primers, and in particular relates to a one-component polyurethane primer and an adhesive tape using the same.

Background technique

In many cases, when using tapes and protective films to bond objects, due to the poor surface affinity of the substrate in the tapes and protective films, it is easy to cause poor structural stability of the tapes, resulting in undesirable phenomenon of debonding, thus failing to achieve the purpose of bonding. PET substrate has good heat resistance, high transparency and strength, is not easy to stretch, and has lower tension control requirements than other substrates. However, due to the regular structure of PET macromolecular chains and high crystallinity, its surface affinity, printability and ink adhesion are poor.

Commonly used methods for substrate surface treatment include corona treatment, but the corona treatment is time-sensitive, and the treatment effect will decay to varying degrees depending on the temperature and humidity of the storage environment and the storage time. Primer, as a pretreatment method, can increase the surface tension of the substrate, thereby improving the structural stability of the tape or protective film and reducing the occurrence of debonding. In addition, since the primer is set between the substrate and the adhesive layer, it improves the bonding performance between the adhesive layer and the substrate, and most of the adhesives on the market contain alcohols, esters, benzenes, and ketones, which can easily corrode the primer.

Therefore, it is necessary to prepare a primer that can increase the surface tension of the substrate and has good solvent resistance.

Summary of the invention

The object of the present invention is to provide a one-component polyurethane primer and an adhesive tape using the same, wherein the one-component polyurethane primer can form a primer layer which has large surface tension, is solvent-resistant, and is not easily corroded by solvents in the adhesive layer, and can improve the surface tension of a substrate.

According to a first aspect of the present invention, a one-component polyurethane primer is provided, and the raw materials for preparing the one-component polyurethane primer include: an alcohol material, the alcohol material includes a polyester polyol, the polyester polyol includes at least one of polyethylene glycol butanediol polyol (PEBA), polyethylene glycol diethylene glycol polyol (PEDA), and polyadipate-3-methyl-1,5-pentanediol polyol (PMA); an isocyanate material, the isocyanate material includes a diisocyanate and a polyisocyanate, the molecular structure of the diisocyanate and/or the polyisocyanate includes an aromatic ring, and calculated by mass ratio, the diisocyanate:polyisocyanate=6-12:1-5; an auxiliary agent, the auxiliary agent includes a catalyst; a solvent; and calculated by mass ratio, the alcohol material:isocyanate material=1-2:0.7-1.7.

The one-component polyurethane primer provided in this scheme can enhance the surface tension of the substrate, and the primer layer formed by the one-component polyurethane primer has high adhesion to the substrate, so that the substrate layer and the primer layer can be firmly attached. At the same time, the primer layer has good solvent resistance and is not easily corroded by alcohols, esters, benzenes, and ketones, so that the tape and protective film using the one-component polyurethane primer have good structural stability. This scheme uses polyester polyols with high polarity and isocyanate materials that meet the above requirements in accordance with the above ratio. The primer obtained has high cohesive strength and can form a primer layer with high surface tension, good adhesion, stable structure, good solvent resistance, good flexibility, and good tensile strength, which is conducive to the firm attachment of the substrate and the primer layer. Among them, the molecular structure of diisocyanate contains 2 isocyanate groups, and the molecular structure of polyisocyanate contains more than 2 isocyanate groups. When the one-component polyurethane primer is used to prepare the tape, the primer layer in the tape is not easily corroded by the adhesive, and the surface tension of the substrate can be stably increased, thereby improving the structural stability of the tape, so that after the tape is attached to the surface of the object and then torn off, it is not easy for residual glue to remain on the surface of the object. Especially when PET is used as the substrate, the one-component polyurethane primer can significantly increase the surface tension of the PET substrate, thereby improving the bonding effect between the PET substrate and the adhesive layer. In addition, the one-component polyurethane primer provided in this scheme is a hydroxyl-terminated polyurethane primer, which is not easy to react with water, avoiding the situation where the primer foams and expands when it encounters water, thereby further improving the storage stability of the primer and the water resistance and solvent resistance of the primer layer.

Preferably, the auxiliary agent includes a hydroxyl chain extender, and the molecular structure of the hydroxyl chain extender contains at least 2 hydroxyl groups; calculated by mass ratio, hydroxyl chain extender: isocyanate material = 0.2-0.5: 0.7-1.7. The above-mentioned hydroxyl chain extender contains at least 2 hydroxyl groups, so the hydroxyl chain extender belongs to an alcohol hydroxyl chain extender, and by using the above-mentioned content of alcohol hydroxyl chain extender and the above-mentioned isocyanate material to cross-link, the speed of the primer to completely dry can be increased, so that the primer has the performance of rapid surface drying, and can be directly dried and rolled up for use, which greatly improves production efficiency.

Preferably, the hydroxyl chain extender includes at least one of ethylene glycol (EG), 1,4-butanediol (BDO), diethylene glycol (DEG), and neopentyl glycol (NPG). When the reaction system contains a hydroxyl chain extender, the isocyanate material will first react with the above-mentioned hydroxyl chain extender with a small molecular weight, and then react with the alcohol material to form a primer. The inventor selected the above-mentioned high-polarity, low-cost, and easily available hydroxyl chain extender and the above-mentioned material system to prepare the primer, which can improve the crosslinking density of the primer, which is conducive to the primer forming a primer layer with high adhesion, stable structure, and high surface tension.

Preferably, the molecular weight of the polyester polyol is 1000 to 2000. By selecting the polyester polyol with the above molecular weight and combining it with isocyanate materials to prepare the primer, it is easy to form a primer layer with moderate hardness, good flexibility and tensile strength, and good solvent resistance, so that the adhesive layer structure using the primer is stable and not easy to have residual adhesive.

Preferably, the diisocyanate includes at least one of toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI). The use of the above-mentioned diisocyanates can not only improve the cohesive strength of the primer, but also easily form a primer layer with high adhesion to the substrate, good solvent resistance and high surface tension.

Preferably, the polyisocyanate includes at least one of toluene diisocyanate-trimethylolpropane adduct (TDI-TMP adduct) and polymethylene polyphenyl isocyanate (PAPI).

Preferably, the solvent includes N,N-dimethylformamide (DMF) and ethyl acetate, and the mass ratio is N,N-dimethylformamide:ethyl acetate=3-5:5-7. The inventors found that the above solvent has good compatibility with the above material system, can accommodate polyurethane with a high hard segment content, promote the dissolution of the one-component polyurethane primer, and avoid agglomeration or agglomeration of the one-component polyurethane primer during storage, thereby improving the storage stability of the one-component polyurethane primer.

Preferably, the catalyst comprises an organobismuth catalyst.

Preferably, the organic bismuth catalyst is a bismuth carboxylate.

Optionally, the organic bismuth catalyst is a bismuth carboxylate catalyst produced by King Industries of the United States with a brand name of K-KAT348.

Preferably, the preparation method of the one-component polyurethane primer comprises the following operations: weighing the raw materials for preparing the one-component polyurethane primer according to the amount, wherein the auxiliary agent comprises a hydroxyl chain extender; prepolymerizing the alcohol material and the isocyanate material at a temperature of 70 to 80°C to obtain a polyurethane prepolymer; adding a hydroxyl chain extender to the polyurethane prepolymer, maintaining the reaction temperature at 70 to 80°C, until the isocyanate value in the reaction system is ≤0.1%. The inventor first prepares an NCO-terminated polyurethane prepolymer by prepolymerization, and then reacts the polyurethane prepolymer with a hydroxyl chain extender to obtain a hydroxyl-terminated polyurethane. The preparation method not only increases the hard segment content of the one-component polyurethane primer, but also effectively avoids the shortcomings of the NCO-terminated polyurethane, such as foaming in water and poor storage stability. In summary, the above-mentioned operation steps are used to prepare the one-component polyurethane primer, which easily makes the formed primer layer have the advantages of high surface tension, stable structure, and rapid surface drying.

According to another aspect of the present invention, there is provided an adhesive tape, which includes a substrate layer, a primer layer, and an adhesive layer arranged in sequence, and the primer layer is made of the above-mentioned single-component polyurethane primer. The adhesive tape provided by this scheme has a stable structure and is not easy to leave adhesive residue. The primer layer in the adhesive tape provides an adhesion surface with higher surface tension for the substrate layer to be attached to the adhesive layer, so that the structure of the adhesive tape is stable. When the adhesive layer is attached to the surface of an object and then torn off, the peeling force between the adhesive layer and the primer layer will be greater than the peeling force between the adhesive layer and most objects, thereby improving the structural stability of the adhesive tape and making it difficult for the adhesive tape to leave adhesive residue on the surface of the object.

Preferably, the substrate layer comprises polyethylene terephthalate. The inventors have found that when polyethylene terephthalate (PET) is selected as the substrate layer, the adhesion between the primer layer and the substrate layer is higher, and a higher surface tension can be provided for the PET substrate layer.

Preferably, the adhesive layer is made of at least one of TP-913 pressure-sensitive adhesive produced by Taiwan Nanbao Resin Company, Y-1410 produced by Anzu Chemical, and PSA-1330 pressure-sensitive adhesive produced by Guangdong Bang Curing Technology.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

Example 1

(1) Preparation of one-component polyurethane primer

The raw materials for preparing the one-component polyurethane primer include alcohol materials, isocyanate materials, additives, and solvents. The alcohol materials are composed of 14.8200 parts of polyester polyols, and the polyester polyols are polyethylene glycol adipate butanediol polyols (PEBA), and the molecular weight of the polyester polyols is 1000. The isocyanate materials are composed of 8.980 parts of diisocyanates and 4.000 parts of polyisocyanates, and the diisocyanates are diphenylmethane diisocyanate (MDI), and the polyisocyanates are toluene diisocyanate-trimethylolpropane adducts (TDI-TMP adducts) with a grade of L-75. The additives are 0.0059 parts of catalysts and 2.1700 parts of hydroxyl chain extenders. The catalyst is a bismuth carboxylate catalyst produced by King Industries in the United States with a grade of K-KAT348. The hydroxyl chain extenders include 1.1000 parts of ethylene glycol (EG) and 1.0700 parts of 1,4-butanediol (BDO). The solvent included 30 parts of N,N-dimethylformamide (DMF) and 45 parts of ethyl acetate.

From the mass fractions of the above materials, it can be calculated that the mass ratio of alcohol materials to isocyanate materials is 1.482:1.298. The mass ratio of diisocyanate to polyisocyanate is 8.980:4.000. The mass ratio of hydroxyl chain extender to isocyanate materials is 0.217:1.298. The mass ratio of N,N-dimethylformamide to ethyl acetate is 4:6.

The one-component polyurethane primer is prepared by the following steps:

S1. Add alcohol materials, isocyanate materials, hydroxyl chain extender ethylene glycol, catalyst, and 15 parts of solvent DMF into a reactor and stir for 15 minutes. Then add diisocyanate, polyisocyanate and 22.5 parts of solvent ethyl acetate to the reaction system, and heat the reaction system to 75°C for prepolymerization. Continue the reaction for 2.5 hours to obtain a polyurethane prepolymer;

S2. Adding a hydroxyl chain extender 1,4-butanediol and 22.5 parts of ethyl acetate as a solvent to the polyurethane prepolymer in multiple portions, maintaining the temperature of the reaction system at 70 to 80°C, and continuing the reaction for 2.5 hours;

S3. When the isocyanate value in the reaction system is ≤0.1%, there is no NCO residue in the reaction system. The remaining 15 parts of solvent DMF are added to the reaction system, stirred for 15 minutes, cooled and collected to obtain a one-component polyurethane primer.

The obtained one-component polyurethane primer was tested, and the hard segment content was 50.59% and the solid content was 30%. According to the actual production and use requirements, the viscosity of the one-component polyurethane primer at 25°C can be in the range of 100 to 300 mPa·s. In other embodiments, the reaction time, NCO theoretical value, and the amount of material fed in batches in S1, S2, and S3 can be adjusted according to production requirements, provided that the total amount of raw materials fed and the normal preparation of the primer are not affected.

(2) Preparation of tape

The adhesive tape comprises a substrate layer, a primer layer, an adhesive layer, and a release film which are compounded in sequence. The primer layer is made of the one-component polyurethane primer provided in (1). The substrate layer is a polyethylene terephthalate (PET) film with a thickness of 50 μm, the adhesive layer is a high-viscosity acrylic pressure-sensitive adhesive with a brand name of TP-913 produced by Taiwan Nanbao Resin Co., Ltd., and the release film has a thickness of 25 μm.

The adhesive tape is prepared by the following steps:

First, the one-component polyurethane primer is diluted with solvent ethyl acetate to a solution with a concentration of 25%, and then the diluted one-component polyurethane primer is coated on the substrate layer with a coating thickness of 0.5 to 1 g/㎡. Then, the substrate layer is transferred to a 120°C environment and dried for 20 to 30 seconds to form a primer layer arranged on one side of the substrate layer to prepare a glue layer intermediate.

On the side of the primer layer facing away from the substrate layer, a high-viscosity acrylic pressure-sensitive adhesive is applied with a coating thickness of 20±1μm, and then it is transferred to a 120°C environment and dried for 20 to 30 seconds to form an adhesive layer. On the side of the adhesive layer facing away from the primer layer, a release film is attached to obtain an adhesive tape. The adhesive tape is transferred to a 50°C environment and aged for 24 hours.

Example 2

(1) Preparation of one-component polyurethane primer

The raw materials for preparing the one-component polyurethane primer include alcohol materials, isocyanate materials, additives, and solvents. The alcohol materials are composed of 16.4200 parts of polyester polyols, and the polyester polyols are polyethylene glycol diglycol polyols (PEDA), and the molecular weight of the polyester polyols is 2000. The isocyanate materials are composed of 7.5700 parts of diisocyanates and 1.6600 parts of polyisocyanates, and the diisocyanates are toluene diisocyanate (TDI), and the polyisocyanates are polymethylene polyphenyl isocyanate (PAPI). The additives contain 0.0049 parts of catalysts and 4.3300 parts of hydroxyl chain extenders. The catalyst is a bismuth carboxylate catalyst produced by King Industries in the United States with a brand name of K-KAT348. The hydroxyl chain extenders include 1.4800 parts of 1,4-butanediol (BDO) and 2.8500 parts of neopentyl glycol (NPG). The solvent included 24.5 parts of N,N-dimethylformamide (DMF) and 45.5 parts of ethyl acetate.

From the mass fractions of the above materials, it can be calculated that the mass ratio of alcohol materials to isocyanate materials is 1.642:0.923. The mass ratio of diisocyanate to polyisocyanate is 8.980:4.000. The mass ratio of hydroxyl chain extender to isocyanate materials is 0.433:0.923. The mass ratio of N,N-dimethylformamide to ethyl acetate is 3.5:6.5.

The preparation steps of the one-component polyurethane primer are similar to those of Example 1, except that the hydroxyl chain extender BDO is added in S1, and the hydroxyl chain extender NPG is added in S2.

The obtained one-component polyurethane primer was tested, and the hard segment content was 45.25% and the solid content was 30%. According to the actual production and use requirements, the viscosity of the one-component polyurethane primer at 25°C can be in the range of 100 to 300 mPa·s. In other embodiments, the reaction time, NCO theoretical value, and the amount of material fed in batches in S1, S2, and S3 can be adjusted according to production requirements, provided that the total amount of raw materials fed and the normal preparation of the primer are not affected.

(2) Preparation of tape

This step and the raw material composition are strictly consistent with Example 1.

Example 3

(1) Preparation of one-component polyurethane primer

The raw materials for preparing the one-component polyurethane primer include alcohol materials, isocyanate materials, additives, and solvents. The alcohol materials are composed of 13.0800 parts of polyester polyols, and the polyester polyols are 7.8500 parts of polyadipate-3-methyl-1,5-pentanediol polyol (PMA) and 5.2300 parts of polyethylene adipate glycol butanediol polyol (PEBA). The molecular weight of PMA is 2000 and the molecular weight of PEBA is 1000. The isocyanate materials are composed of 11.49 parts of diisocyanate and 1.7500 parts of polyisocyanate. The diisocyanate is diphenylmethane diisocyanate (MDI) and the polyisocyanate is polymethylene polyphenyl isocyanate (PAPI). The additive contains 0.00523 parts of catalyst and 3.6600 parts of hydroxyl chain extender, the catalyst is a bismuth carboxylate catalyst with the brand name K-KAT348 produced by King Industries in the United States, and the hydroxyl chain extender includes 1.3000 parts of ethylene glycol (EG) and 2.3600 parts of 1,4-butanediol (BDO). The solvent includes 24.5 parts of N,N-dimethylformamide (DMF) and 45.5 parts of ethyl acetate.

From the mass fractions of the above materials, it can be calculated that the mass ratio of alcohol materials to isocyanate materials is 1.308:1.497. The mass ratio of diisocyanate to polyisocyanate is 11.4900:1.7500. The mass ratio of hydroxyl chain extender to isocyanate materials is 0.366:1.497. The mass ratio of N,N-dimethylformamide to ethyl acetate is 4.5:5.5.

The preparation steps of the one-component polyurethane primer are strictly consistent with those in Example 1.

The obtained one-component polyurethane primer was tested, and the hard segment content was 56.38% and the solid content was 30%. According to the actual production and use requirements, the viscosity of the one-component polyurethane primer at 25°C can be in the range of 100 to 300 mPa·s. In other embodiments, the reaction time, NCO theoretical value, and the amount of material fed in batches in S1, S2, and S3 can be adjusted according to production requirements, provided that the total amount of raw materials fed and the normal preparation of the primer are not affected.

(2) Preparation of tape

This step and the raw material composition are strictly consistent with Example 1.

Example 4

This embodiment refers to the preparation method provided in Example 1 to prepare an adhesive tape. The difference between this embodiment and Example 1 is that in the process of preparing the one-component polyurethane primer, the mass ratio of diisocyanate to polyisocyanate is 10:1 while keeping the feeding amount of isocyanate materials unchanged. The other raw material ratios and preparation methods are strictly consistent with those in Example 1.

Example 5

This embodiment refers to the preparation method provided in Example 1 to prepare an adhesive tape. The difference between this embodiment and Example 1 is that in the process of preparing the one-component polyurethane primer, the amount of isocyanate material is adjusted so that the mass ratio of alcohol material to isocyanate material is 1.5:1. The other raw material ratios and preparation methods are strictly consistent with those in Example 1.

Example 6

This embodiment refers to the preparation method provided in Example 1 to prepare an adhesive tape. The difference between this embodiment and Example 1 is that in the process of preparing the one-component polyurethane primer, a polyester polyol with an equal mass and a molecular weight of 1500 is selected to replace the polyester polyol in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

Example 7

This embodiment refers to the preparation method provided in Example 1 to prepare an adhesive tape. The difference between this embodiment and Example 1 is that in the process of preparing the one-component polyurethane primer, the following steps replace the step-by-step preparation operations of S1 and S2: the alcohol material, the isocyanate material, all the auxiliary agents, and part of the solvent are stirred evenly, and the reaction system is heated to 75°C and stirred for 5 hours. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

Comparative Example 1

This comparative example refers to the preparation method provided in Example 1 to prepare an adhesive tape. The difference between this comparative example and Example 1 is that in the process of preparing the one-component polyurethane primer, an equal mass of diisocyanate is selected to replace the polyisocyanate in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

Comparative Example 2

This comparative example refers to the preparation method provided in Example 1 to prepare an adhesive tape. The difference between this comparative example and Example 1 is that in the process of preparing the one-component polyurethane primer, an equal mass of HDI biuret is used to replace the polyisocyanate in Example 1, and an equal mass of isophorone diisocyanate is used to replace the diisocyanate in Example 1. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

Comparative Example 3

This comparative example refers to the preparation method provided in Example 1 to prepare an adhesive tape. The difference between this comparative example and Example 1 is that in the process of preparing the one-component polyurethane primer, the amount of the isocyanate material is adjusted so that the mass ratio of the alcohol material to the isocyanate material is 1:2. The other raw material ratios and preparation methods are strictly consistent with Example 1.

Comparative Example 4

This comparative example refers to the preparation method provided in Example 1 to prepare an adhesive tape. The difference between this comparative example and Example 1 is that in the process of preparing the one-component polyurethane primer, the amount of isocyanate material is adjusted so that the mass ratio of alcohol material to isocyanate material is 2:0.5. The other raw material ratios and preparation methods are strictly consistent with Example 1.

Comparative Example 5

This comparative example refers to the preparation method provided in Example 1 to prepare an adhesive tape. The difference between this comparative example and Example 1 is that in the process of preparing the adhesive tape, the coating of the one-component polyurethane primer is omitted, and the high-viscosity acrylic pressure-sensitive adhesive is directly coated on the substrate layer. The rest of the raw material ratios and preparation methods are strictly consistent with those in Example 1.

Test Example 1

1. Performance test of one-component polyurethane primer

Test object: the adhesive layer intermediate provided in Examples 1 to 7 and Comparative Examples 1 to 5. The adhesive layer intermediate comprises a substrate layer and a primer layer which are compounded in sequence, and the primer layer is prepared from the single-component polyurethane primer provided in Examples 1 to 7 and the primer provided in Comparative Examples 1 to 5, respectively.

Test items and test methods:

(1) Surface drying test: Cut the test object into 50mm*50mm pieces and place them on a horizontal table. Use a 25mm*50mm*50um PET original film to adhere the test object. If the PET original film can produce adhesion with the test object, it means that the coating is not surface dry, so the next step of testing is not performed.

(2) Corona value test: First, clean the surface of the test object and lay it flat on a horizontal table. Use a corona pen to lightly draw a line on the surface where the primer layer of the test object is located. If the liquid does not shrink within three seconds, the dyne value selected by the corona pen is reached, otherwise it is not reached. In this test, the substrate layer is set as the blank control group, and the surface dyne value of the blank control group is recorded.

(3) Back adhesion test: Cut the test object into 100mm*100mm size, laminate it with 50um PET original film, press the test object with 1kg pressing block, and place it in a 40℃ oven for 24h. After cooling to room temperature, test the peeling force between the primer layer and the original film in the test object. If the peeling force is 0, proceed to the next step. If the peeling force is tested, it means that the primer has poor temperature resistance and will be sticky in the actual roll sample. It has no practical application value and there is no need to proceed to the next step.

(4) Adhesion test: According to GB/T9286-1998, apply the coating on the 50um PET original film with a coating thickness of 3-5um. Use a 1mm spacing grid knife to scrape out 100 small squares. Use M600 or 610 tape to stick to the grids. Quickly pull up the 3M tape and test the number of peelings. If the number of peelings is ≤5% (i.e., above grade 4B), it is judged as qualified and enters the next step of testing.

2. Performance test of tape

Test objects: the adhesive tapes provided in Examples 1 to 7 and Comparative Examples 1 to 5.

Test items and test methods:

(1) 180° peel strength test: According to the test method in GB/T 2792-2014 Test method for peel strength of adhesive tape, the test object is cut into a size of 24mm*150mm, and the test object is spread on the glass, rolled back and forth three times with a 1kg rubber roller, and left at room temperature for 20 minutes. Then, the test object is peeled off from the glass at a peeling speed of 300mm/min, and the peel strength test is carried out, and whether there is residual adhesive on the glass is recorded.

Test results: The test results are shown in Table 1.

Table 1. Performance test results of one-component polyurethane primer and tape

Result analysis:

By comparing the test indicators of Examples 1 to 7 with those of Comparative Examples 1 to 5 in Table 1, it can be found that the one-component polyurethane primers provided in Examples 1 to 7 can all improve the corona value of the substrate layer, and have stable structure, good storage stability, and good solvent resistance. Among them, in the actual production test process, the one-component polyurethane primers provided in Comparative Examples 1 to 3 have obvious problems of poor storage stability. This is because the reaction R value in Comparative Examples 1 to 3 is too large, the formed polyurethane reaction has poor regularity, and the film is hard and brittle. Therefore, although the primers provided in Comparative Examples 1 to 3 can improve the surface corona value of the substrate layer in a short time, the structural stability is poor and it is impossible to provide a high corona value for a long time.

By comparing the performance of Examples 1 to 7 in Table 1 with that of Comparative Example 4, it can be found that the primer in Comparative Example 4 is difficult to dry on the surface. This is because the reaction R value in Comparative Example 4 is too small, which is equivalent to an excess of -OH, and is difficult to dry on the surface.

By comparing the performance of Examples 1 to 7 with Comparative Example 5, it can be found that the pretreatment method of the one-component polyurethane primer in Examples 1 to 7 not only improves the surface dyne value of the substrate layer, but also improves the structural stability of the tape. This shows that the one-component polyurethane primer has good solvent resistance and structural stability while being able to improve the surface tension of the substrate layer.

The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims (10)

1. A one-component polyurethane primer, characterized in that the raw materials for preparing the one-component polyurethane primer include: Alcohol materials, wherein the alcohol materials include polyester polyols, and the polyester polyols include at least one of polyethylene adipate glycol butanediol polyol, polyethylene adipate glycol diethylene glycol polyol, and polyadipate-3 methyl-1,5-pentanediol polyol; Isocyanate materials, wherein the isocyanate materials include diisocyanates and polyisocyanates, wherein the molecular structure of the diisocyanates and/or the polyisocyanates includes aromatic rings, and the mass ratio of the diisocyanate to the polyisocyanate is 6-12:1-5; Auxiliary agents, wherein the auxiliary agents include catalysts; Solvents; And calculated according to the mass ratio, the alcohol material: the isocyanate material = 1-2: 0.7-1.7. 2. The one-component polyurethane primer as described in claim 1 is characterized in that the auxiliary agent includes a hydroxyl type chain extender, and the molecular structure of the hydroxyl type chain extender contains at least 2 hydroxyl groups; calculated by mass ratio, the hydroxyl type chain extender: the isocyanate material = 0.2~0.5:0.7~1.7. 3. The one-component polyurethane primer as claimed in claim 2, characterized in that the hydroxyl type chain extender comprises at least one of ethylene glycol, 1,4-butanediol, diethylene glycol and neopentyl glycol. 4. The one-component polyurethane primer according to claim 1, characterized in that the molecular weight of the polyester polyol is 1000-2000. 5. The one-component polyurethane primer according to claim 1, characterized in that the diisocyanate comprises at least one of toluene diisocyanate and diphenylmethane diisocyanate. 6. The one-component polyurethane primer as claimed in claim 5, characterized in that the polyisocyanate comprises at least one of toluene diisocyanate-trimethylolpropane adduct and polymethylene polyphenyl isocyanate. 7. The one-component polyurethane primer as claimed in claim 1, characterized in that the solvent comprises N,N-dimethylformamide and ethyl acetate, and calculated by mass ratio, the N,N-dimethylformamide: the ethyl acetate = 3-5:5-7. 8. A one-component polyurethane primer according to any one of claims 1 to 7, characterized in that the preparation method thereof comprises the following operations: Weighing raw materials for preparing the one-component polyurethane primer according to quantity, wherein the auxiliary agent includes a hydroxyl type chain extender; Prepolymerizing the alcohol material and the isocyanate material at a temperature of 70 to 80° C. to obtain a polyurethane prepolymer; The hydroxyl type chain extender is added to the polyurethane prepolymer, and the reaction temperature is maintained at 70-80° C. until the isocyanate value in the reaction system is ≤0.1%. 9. An adhesive tape, characterized in that the adhesive tape comprises a substrate layer, a primer layer, and an adhesive layer arranged in sequence, and the primer layer is made of the one-component polyurethane primer according to any one of claims 1 to 8. 10. The adhesive tape of claim 9, wherein the substrate layer comprises polyethylene terephthalate.