Polyurethane acrylate for UV light-curing adhesive and preparation method and application thereof

Abstract

The present invention belongs to the technical field of polyurethane acrylate, and specifically relates to a polyurethane acrylate for UV light-curing adhesive, and a preparation method and application thereof. The polyurethane acrylate for UV light-curing adhesive described in the present invention is made of the following raw materials: 30-80 parts of unsaturated polyester polyol, 24-32 parts of isocyanate intermediate, and 2-6 parts of hydroxy acrylate; the unsaturated polyester polyol is prepared using unsaturated small molecule dibasic acid, saturated small molecule dibasic acid, and small molecule diol as raw materials; the isocyanate intermediate is prepared by reacting isocyanate monomer with polyol. The polyurethane acrylate for UV light-curing adhesive of the present invention is applied to the preparation of UV light-curing polyurethane acrylate adhesive, which improves the ability of UV light-curing adhesive to resist high temperature and high humidity, and improves its service life; the present invention also provides its preparation method.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane acrylate, and specifically relates to polyurethane acrylate for UV light-curing adhesive and a preparation method and application thereof. Background Art

[0002] Polyurethane adhesives have the advantages of high bonding strength, long service life, and high structural design. Polyester adhesives have high bonding ability with polar substrates due to the presence of polar groups such as ester groups, and their own mechanical strength is excellent. They are widely used in various fields such as construction, automobiles, and medical treatment. As a branch of polyurethane adhesives, UV light-curing polyurethane acrylate adhesives have the characteristics of energy saving, environmental protection, and economic efficiency. However, there are still some shortcomings during use, such as insufficient hydrolysis resistance, insufficient weather resistance, and short service life in complex environments. As an important component of UV light-curing adhesives, the structure and performance of polyurethane acrylates will have a great impact on UV light-curing adhesives.

[0003] CN114874743A discloses a high-adhesion UV light-curing polyurethane acrylate adhesive and a preparation method thereof. Polyurethane acrylate is prepared from polyester polyol, isocyanate, hydroxyethyl acrylate, an inhibitor and a catalyst as raw materials, and the polyurethane acrylate is applied to a UV light-curing polyurethane acrylate adhesive to obtain a high-adhesion UV light-curing polyurethane acrylate adhesive with excellent mechanical strength. However, the polyester polyol used in the polyurethane adhesive system has low functionality, and there is no other raw material for increasing functionality in the system, which is not conducive to long-term use of the product under hot and humid conditions. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects of the prior art, provide polyurethane acrylate for UV light-curing adhesive, improve the ability of UV light-curing adhesive to resist high temperature and high humidity, improve its service life, and be applied to the preparation of UV light-curing polyurethane acrylate adhesive; the present invention also provides a preparation method thereof.

[0005] The polyurethane acrylate for UV light-curing adhesive of the present invention is prepared from the following raw materials in parts by weight: 30-80 parts of unsaturated polyester polyol, 24-32 parts of isocyanate intermediate, and 2-6 parts of hydroxy acrylate.

[0006] The unsaturated polyester polyol is prepared by using unsaturated small molecule dibasic acid, saturated small molecule dibasic acid and small molecule diol as raw materials under the action of catalyst A, hindered phenol antioxidant and polymerization inhibitor.

[0007] The isocyanate intermediate is an isocyanate-terminated prepolymer obtained by chain extension reaction of isocyanate monomer and polyol in the presence of catalyst B.

[0008] The catalyst A is an organic titanium catalyst, preferably tetrabutyl titanate; the catalyst B is an organic tin catalyst, preferably stannous chloride.

[0009] The hydroxy acrylate is one of hydroxyethyl acrylate and hydroxypropyl acrylate, preferably hydroxyethyl acrylate (HEA).

[0010] The unsaturated small molecule dibasic acid is one of fumaric acid, maleic acid, and itaconic acid, preferably maleic acid. The small molecule diol is a branched diol with a carbon number of ≥5, and the branched diol is one of neopentyl glycol, ethyl butyl propanediol, and 2,2,4-trimethyl-1,3-pentanediol, preferably neopentyl glycol.

[0011] The saturated small molecule dibasic acid is composed of an aromatic dibasic acid and an aliphatic small molecule dibasic acid with a carbon number ≥ 10. The aromatic dibasic acid is one of isophthalic acid and terephthalic acid. The aliphatic small molecule dibasic acid is one of sebacic acid, dodecanedioic acid, and dimer acid. The aromatic dibasic acid is preferably isophthalic acid, and the aliphatic small molecule dibasic acid is preferably sebacic acid.

[0012] The isocyanate monomer is one of isophorone diisocyanate, toluene diisocyanate and diphenylmethane diisocyanate, preferably isophorone diisocyanate; the polyol is one of trimethylolpropane and glycerol, preferably trimethylolpropane.

[0013] The hindered phenol antioxidant is RIANOX ® 1010, RIANOX ® 1076、RIANOX ® One of 1024, preferably RIANOX ® 1010.

[0014] The polymerization inhibitor is one of 1,1-diphenyl-2-trinitrophenylhydrazine, p-tert-butylcatechol and hydroquinone, preferably p-tert-butylcatechol.

[0015] The method for preparing the polyurethane acrylate for UV light-curing adhesive comprises the following steps:

[0016] (1) Preparation of unsaturated polyester polyol: unsaturated small molecule dibasic acid, saturated small molecule dibasic acid, small molecule diol, catalyst A, hindered phenol antioxidant, and polymerization inhibitor are added to a reactor, stirring is started, the temperature is increased to carry out esterification-ester exchange reaction, the hydroxyl value is measured, and the temperature is reduced to obtain unsaturated polyester polyol;

[0017] (2) Preparation of isocyanate intermediate: put isocyanate monomer and polyol into a reactor, mix them evenly, raise the temperature, add catalyst B, and react at 45-50°C to obtain isocyanate intermediate;

[0018] (3) Synthesis of polyurethane acrylate for UV light-curing adhesive: unsaturated polyester polyol and isocyanate intermediate are added into a reactor, heated to 80-85°C for reaction, cooled after the reaction is completed, hydroxy acrylate is added, and the reaction is continued at 60-65°C until the NCO content of the test system is ≤0.3wt.%, thereby obtaining polyurethane acrylate for UV light-curing adhesive.

[0019] In the step (1), the unsaturated small molecule dibasic acid accounts for 1-3% of the total molar amount of the unsaturated small molecule dibasic acid and the saturated small molecule dibasic acid, and the ratio of the total molar amount of the unsaturated small molecule dibasic acid and the saturated small molecule dibasic acid to the total molar amount of the small molecule diol is 1:1.15-1.4.

[0020] The application of the polyurethane acrylate for UV light-curing adhesive is to use it to prepare a moisture- and heat-resistant UV light-curing polyurethane acrylate adhesive, which specifically includes the following process: stirring polyurethane acrylate, isobornyl acrylate, and diphenyl-(2,4,6-trimethylbenzoyl)phosphine at 60-65° C., and degassing under a vacuum of -0.08 MPa to -0.1 MPa to obtain a moisture- and heat-resistant UV light-curing polyurethane acrylate adhesive.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) In the present invention, maleic acid is introduced into the unsaturated polyester polyol preparation process to participate in the reaction. The generated maleic anhydride increases the unsaturation in the chain segment, and the carbon-carbon double bond content in the polyurethane acrylate system is adjusted by the addition amount of maleic acid. The carbon-carbon double bonds in the maleic anhydride will participate in the reaction during the UV light curing process, further improving the crosslinking degree of the system and improving the mechanical properties of the UV light-curing polyurethane acrylate adhesive; at the same time, through the reaction of the isocyanate intermediate, the crosslinking degree of the system is further improved, making the overall structure more compact and improving its hydrolysis resistance.

[0023] (2) The present invention makes targeted selection of small molecule acids and small molecule alcohols when preparing unsaturated polyester polyols, introduces neopentyl glycol, isophthalic acid and sebacic acid, effectively reduces the crystallinity of polyurethane acrylate, makes it still have good fluidity at low temperature, and enhances its applicability. At the same time, sebacic acid with a longer molecular chain is selected for the synthesis of polyester polyols. Compared with adipic acid commonly used in polyester polyol products, the number of ester groups in polyester polyols with the same molecular weight is significantly reduced, and the hydrolysis rate of the polyurethane chain segment is slowed down by reducing the ester group density. At the same time, benzene rings are added to the chain segment to improve the heat resistance of the material, further increasing the high temperature and high humidity resistance of the UV light-curing polyurethane acrylate adhesive.

[0024] (3) The present invention effectively utilizes the different activities of the two NCO groups in isophorone diisocyanate. The isocyanate monomer is reacted with the polyol at a low temperature of 45-50°C to prepare the isocyanate intermediate, and the polyurethane acrylate is reacted at a high temperature of 80-85°C. The step-by-step reaction in the preparation process of the polyurethane acrylate makes the overall process more controllable, and the polyurethane structure is more regular and has better performance.

[0025] (4) The polyurethane acrylate prepared by the present invention has a high degree of crosslinking and a fast reaction activity. When applied to UV light-curing adhesives, it has a fast initial reaction speed, better initial adhesion, and better bonding performance. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with embodiments and comparative examples, but they do not limit the implementation of the present invention.

[0027] The raw materials used in the examples and comparative examples are conventional commercially available raw materials unless otherwise specified, and the process methods used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0028] The raw materials used in the embodiments and comparative examples are described as follows:

[0029] Maleic acid: Shandong Poly Chemical Co., Ltd.;

[0030] Neopentyl glycol: Binzhou Xinkeaode Technology Co., Ltd.;

[0031] Sebacic acid: Wilmar Oil & Fats Technology Co., Ltd.;

[0032] Isophthalic acid: Sinopec Yanshan Petrochemical Company;

[0033] Isophorone diisocyanate (IPDI): Bayer AG, Germany;

[0034] Trimethylolpropane: PetroChina Co., Ltd.

[0035] n-Butyl titanate: Shandong Heruidong Fine Chemical Co., Ltd.;

[0036] Stannous chloride: Hubei Xinghengye Technology Co., Ltd.;

[0037] Hydroxyethyl acrylate (HEA): Taiwan Double Bond Chemical Co., Ltd.;

[0038] RIANOX ® 1010: Tianjin Lianlong New Materials Co., Ltd.

[0039] 4-tert-Butylcatechol: Shandong Xinghai Chemical Co., Ltd.;

[0040] Diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (TPO): Taiwan Double Bond Chemical Co., Ltd.;

[0041] Isobornyl acrylate (IBOA): Taiwan Double Bond Chemical Co., Ltd.;

[0042] PE-7020: A polyester polyol with a functionality of 2 and an average molecular weight of 2000 synthesized from adipic acid and neopentyl glycol, produced by Shandong Yinuowei Polyurethane Co., Ltd.

[0043] The method for preparing the polyurethane acrylate for UV light-curing adhesive comprises the following steps:

[0044] (1) Preparation of unsaturated polyester polyol: weigh unsaturated small molecule dibasic acid, saturated small molecule dibasic acid, and small molecule diol, place in a reactor equipped with stirring, reflux, and nitrogen devices, add 30 ppm of catalyst A, 300 ppm of hindered phenol antioxidant, and 30 ppm of polymerization inhibitor, start stirring and heating, and carry out esterification-ester exchange reaction under nitrogen protection, react at 220° C. until the hydroxyl value reaches 56.1-112.2 mgKOH / g, then cool to obtain unsaturated polyester polyol;

[0045] (2) Preparation of isocyanate intermediate: 3 mol of isophorone diisocyanate and 1 mol of trimethylolpropane were added into a reactor, mixed evenly, heated, and 30 ppm of stannous chloride was added. The reaction was continued at 47.5±2.5°C until the NCO content of the system reached 15.75±0.25 wt.%, and the reaction was completed to obtain an isocyanate intermediate (IPDI-M).

[0046] (3) Synthesis of polyurethane acrylate for UV light-curing adhesive: unsaturated polyester polyol and isocyanate intermediate are added into a reactor and heated to 80-85°C for reaction. After the reaction is completed, the temperature is lowered to 60°C and hydroxy acrylate is added. The reaction is continued at 62.5±2.5°C until the NCO content of the test system is ≤0.3%. Polyurethane acrylate for UV light-curing adhesive is obtained.

[0047] The specific process of preparing the moisture-heat resistant UV light-curing polyurethane acrylate adhesive is as follows: 80 parts of polyurethane acrylate, 17 parts of isobornyl acrylate, and 3 parts of diphenyl-(2,4,6-trimethylbenzoyl)phosphine are stirred at 60° C. for 30 minutes at a stirring speed of 1000 r / min, and then degassed at a vacuum of -0.09±0.01 MPa for 30 minutes to obtain the moisture-heat resistant UV light-curing polyurethane acrylate adhesive.

[0048] Example 1

[0049] The method for preparing the polyurethane acrylate for UV light-curing adhesive comprises the following steps:

[0050] (1) Preparation of unsaturated polyester polyol: 5.0 mol of sebacic acid, 4.9 mol of isophthalic acid, 0.1 mol of maleic acid, and 11.5 mol of neopentyl glycol were placed in a reactor equipped with a stirring, reflux, and nitrogen device, and 30 ppm of tetrabutyl titanate and 300 ppm of RIANOX were added. ® 1010, 30ppm of p-tert-butylcatechol, stirring and heating, esterification-ester exchange reaction under nitrogen protection, reaction at 220℃, hydroxyl value of 56.1mgKOH / g, cooling, unsaturated polyester polyol (polyester 1) with an average molecular weight of 2000 is obtained;

[0051] (2) Preparation of isocyanate intermediate: 3 mol of isophorone diisocyanate and 1 mol of trimethylolpropane were added into a reactor, mixed evenly, heated, and 30 ppm of stannous chloride was added. The reaction was continued at 47.5±2.5°C until the NCO content of the system reached 15.75±0.25 wt.%, and the reaction was completed to obtain an isocyanate intermediate.

[0052] (3) Synthesis of polyurethane acrylate for UV light-curing adhesive: 80 parts of unsaturated polyester polyol and 32 parts of isocyanate intermediate were added into a reactor and heated to 82.5±2.5°C for reaction. After the reaction was completed, the temperature was lowered to 60°C and 4 parts of hydroxy acrylate were added. The temperature was kept at 62.5±2.5°C for reaction until the NCO content of the test system was ≤0.3wt.%, thereby obtaining polyurethane acrylate for UV light-curing adhesive.

[0053] The specific process of preparing the moisture-heat resistant UV light-curing polyurethane acrylate adhesive is as follows: 80 parts of the UV light-curing adhesive polyurethane acrylate prepared in this embodiment, 17 parts of isobornyl acrylate, and 3 parts of diphenyl-(2,4,6-trimethylbenzoyl)phosphine are stirred at 60° C. for 30 minutes at a stirring speed of 1000 r / min, and then degassed at a vacuum of -0.09±0.01 MPa for 30 minutes to obtain a moisture-heat resistant UV light-curing polyurethane acrylate adhesive.

[0054] Embodiment 2-4

[0055] (1) The raw materials and indicators used in preparing the unsaturated polyester polyols (polyester 2 to polyester 4) described in Examples 2-4 are shown in Table 1. The preparation methods and steps of the unsaturated polyester polyols described in Examples 2-4 are the same as those in Example 1;

[0056] (2) The raw materials and specific process for preparing the isocyanate intermediate in Example 2-4 are the same as those in Example 1;

[0057] (3) The unsaturated polyester polyol and isocyanate intermediate prepared in each example are used to prepare polyurethane acrylate for UV light-curing adhesive. The types and amounts of raw materials used are shown in Table 2. The preparation method and steps are the same as those in Example 1.

[0058] (4) Except for the type of polyurethane acrylate used in the UV light-curing adhesive, the specific process of the moisture-heat-resistant UV light-curing polyurethane acrylate adhesive described in Examples 2-4 is the same as that in Example 1.

[0059] Table 1 Raw materials and indexes of Examples 2-4

[0060]

[0061] Table 2: Raw materials for synthesizing polyurethane acrylate for UV light-curing adhesive in Example 2-4

[0062]

[0063] Comparative Example 1

[0064] The method for preparing the polyurethane acrylate for UV light-curing adhesive comprises the following steps:

[0065] (1) 5.0 mol of sebacic acid, 5.0 mol of isophthalic acid, and 11.5 mol of neopentyl glycol were placed in a reactor equipped with a stirring, reflux, and nitrogen device, and 30 ppm of tetrabutyl titanate, 30 ppm of p-tert-butyl catechol, and 300 ppm of RIANOX were added. ®1010, start stirring and heating, carry out esterification-ester exchange reaction under nitrogen protection, react at 220°C, and measure the hydroxyl value to be 56.1 mgKOH / g. Cool down to obtain saturated polyester polyol (polyester 5) with an average molecular weight of 2000;

[0066] (2) In Comparative Example 1, no isocyanate intermediate preparation is required, and IPDI of the same weight is used instead;

[0067] (3) Synthesis of polyurethane acrylate for UV light-curing adhesive The specific process for preparing the moisture-heat-resistant UV light-curing polyurethane acrylate adhesive is the same as that in Example 1. The raw materials used and their weight parts are shown in Table 3.

[0068] Comparative Examples 2-4

[0069] The types and weight fractions of raw materials used in the preparation of polyurethane acrylate for UV light-curing adhesives in Comparative Examples 2-4 are shown in Table 3, and the preparation steps are the same as those in Example 1; the polyurethane acrylate for UV light-curing adhesives prepared in Comparative Examples 2-4 are used to prepare moisture- and heat-resistant UV light-curing polyurethane acrylate adhesives. Except for the different types of polyurethane acrylate for UV light-curing adhesives, the other raw materials, weight fractions of raw materials, and the preparation process are the same as those in Example 1.

[0070] Table 3 Comparative Examples 1-4 Raw Materials

[0071]

[0072] The UV light-curable polyurethane acrylate adhesives prepared in Examples 1-4 and Comparative Examples 1-4 were cured under a UV lamp. The UV light curing conditions were: using LED ultraviolet light with a wavelength of 395 nm for curing, and the radiation intensity was 1500 mJ / cm 2 , curing time is 30s, performance test is carried out after UV light curing, and the test results are shown in Table 4-Table 6.

[0073] The tensile strength and elongation at break are determined according to GB / T529-2009; hardness determination: the hardness of the adhesive sample is tested according to GB / T2411-2008, and the sample thickness is 4mm; the peel strength is determined according to GB / T2790-1995, where the flexible material is polyimide film, the material is glass, the adhesive layer width is 25mm, the thickness is 0.5mm, and the maximum peel force value is recorded; wet heat aging performance test: the double 85 test is used to detect the adhesive's ability to resist wet heat aging. The UV-cured sample is placed in a constant temperature and humidity chamber with a temperature of 85°C and a humidity of 85%, and its various properties are tested after 200 hours; the tensile strength retention rate and the peel strength retention rate are the ratio of the performance data after the double 85 test to the performance data before the test.

[0074] Table 4 Test results of tensile strength and elongation at break of double 85 before and after test

[0075]

[0076] Table 5 Hardness test results before and after double 85 test

[0077]

[0078] Table 6 Peel strength test results of double 85 before and after test

[0079]

[0080] It can be seen from Tables 4 to 6 that, through Example 1 and Comparative Example 1, the adhesive prepared using unsaturated polyester polyols does not have a large difference in initial mechanical properties and hardness compared with the adhesive prepared using saturated polyester polyols, but has a certain improvement in peel strength, and after the double 85 test, the performance loss is less. The reason is that the introduction of unsaturated double bonds in polyester polyols can participate in the free radical polymerization of double bonds during UV light curing, thereby improving the bonding strength of the adhesive and improving the peel strength. At the same time, the formation of unsaturated double bonds is conducive to the formation of a network structure of the adhesive, thereby improving the service life of the adhesive in a high temperature and high humidity environment.

[0081] It can be seen from Example 1, Comparative Example 2 and Comparative Example 3 that, by comparing the conventional polyester and the unsaturated polyester polyol prepared by the present invention, even when IPDI-M is used, the adhesive prepared by using the unsaturated polyester polyol has improved properties. The reason is that the embodiments use sebacic acid with a relatively long molecular chain and isophthalic acid with a benzene ring structure. The use of long-chain small molecular acids can reduce the ester content in the polyester polyol system, thereby reducing the performance degradation caused by the hydrolysis of ester groups in a high-humidity environment, and the introduction of small molecular acids with a benzene ring structure can improve the high temperature resistance of the polyester polyol. In Comparative Example 3 where no isocyanate intermediate is used, it is found that the adhesive performance is seriously degraded, especially after the double 85 test. The reason for this result is that the use of conventional polyester polyols reduces the crosslinking degree of the adhesive to a certain extent, while the use of IPDI instead of the isocyanate intermediate reduces the overall functionality of the adhesive, further reduces the crosslinking degree of the adhesive, makes the adhesive very easy to hydrolyze, and seriously reduces the product life.

[0082] By comparing Example 1 with Comparative Example 4, it can be seen that when the isocyanate intermediate IPDI-M prepared by the present invention is not used, the performance is more severely lost after the double 85 test. This is because the introduction of the isocyanate intermediate IPDI-M improves the overall functionality of the polyurethane adhesive system, making the structure of the system denser after curing, and making it difficult for water molecules to enter the interior of the structure, thereby slowing down the performance loss in a high humidity environment.

Claims

1. A polyurethane acrylate for UV light-curing adhesive, characterized in that: The method is prepared from the following raw materials in parts by weight: 30-80 parts of unsaturated polyester polyol, 24-32 parts of isocyanate intermediate, and 2-6 parts of hydroxy acrylate; The unsaturated polyester polyol is prepared by using unsaturated small molecule dibasic acid, saturated small molecule dibasic acid and small molecule diol as raw materials under the action of catalyst A, hindered phenol antioxidant and polymerization inhibitor; The unsaturated small molecule dibasic acid is one of fumaric acid, maleic acid, and itaconic acid; the small molecule diol is a branched diol with a carbon number of ≥5, and the branched diol is one of neopentyl glycol, ethyl butyl propylene glycol, and 2,2,4-trimethyl-1,3-pentanediol; The saturated small molecule dibasic acid is composed of an aromatic dibasic acid and an aliphatic small molecule dibasic acid with a carbon number of ≥10, the aromatic dibasic acid is one of isophthalic acid and terephthalic acid, and the aliphatic small molecule dibasic acid is one of sebacic acid, dodecanedioic acid, and dimer acid; the unsaturated small molecule dibasic acid accounts for 1-3% of the total molar amount of the unsaturated small molecule dibasic acid and the saturated small molecule dibasic acid; The isocyanate intermediate is an isocyanate-terminated prepolymer obtained by chain extension reaction of isocyanate monomer and polyol in the presence of catalyst B; The isocyanate monomer is one of isophorone diisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate, and the polyol is one of trimethylolpropane and glycerol; The catalyst A is an organic titanium catalyst, and the catalyst B is an organic tin catalyst.

2. The polyurethane acrylate for UV light-curing adhesive according to claim 1, characterized in that: The hydroxy acrylate is one of hydroxyethyl acrylate and hydroxypropyl acrylate.

3. The polyurethane acrylate for UV light-curing adhesive according to claim 1, characterized in that: The hindered phenol antioxidant is RIANOX ® 1010, RIANOX ® 1076、RIANOX ® One of 1024.

4. The polyurethane acrylate for UV light-curing adhesive according to claim 1, characterized in that: The polymerization inhibitor is one of 1,1-diphenyl-2-trinitrophenylhydrazine, p-tert-butylcatechol and hydroquinone.

5. A method for preparing the polyurethane acrylate for UV light-curing adhesive according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Preparation of unsaturated polyester polyol: unsaturated small molecule dibasic acid, saturated small molecule dibasic acid, small molecule diol, catalyst A, hindered phenol antioxidant, and polymerization inhibitor are added to a reactor, stirring is started, the temperature is increased to carry out esterification-ester exchange reaction, the hydroxyl value is measured, and the temperature is reduced to obtain unsaturated polyester polyol; (2) Preparation of isocyanate intermediate: put isocyanate monomer and polyol into a reactor, mix them evenly, raise the temperature, add catalyst B, and react at 45-50°C to obtain isocyanate intermediate; (3) Synthesis of polyurethane acrylate for UV light-curing adhesive: unsaturated polyester polyol and isocyanate intermediate are added into a reactor, heated to 80-85°C for reaction, cooled after the reaction is completed, hydroxy acrylate is added, and the reaction is continued at 60-65°C until the NCO content of the test system is ≤0.3wt.%, thereby obtaining polyurethane acrylate for UV light-curing adhesive.

6. The method for preparing polyurethane acrylate for UV light-curing adhesive according to claim 5, characterized in that: In the step (1), the ratio of the total molar amount of the unsaturated small molecule dibasic acid and the saturated small molecule dibasic acid to the total molar amount of the small molecule diol is 1:1.15-1.

4.

7. An application of the polyurethane acrylate for UV light-curing adhesive according to any one of claims 1 to 4, characterized in that: The polyurethane acrylate for UV light-curing adhesive is mixed with isobornyl acrylate and diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, stirred at 60-65° C., and degassed under a vacuum of -0.08 MPa to -0.1 MPa to prepare a moisture-heat-resistant UV light-curing polyurethane acrylate adhesive.

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