CN105062375B - A kind of Liquid optical clear adhesive of ultraviolet light solidification and preparation method and application - Google Patents

Abstract

The invention relates to a novel liquid optically transparent adhesive cured by ultraviolet light, a preparation method and application thereof. The transparent glue comprises the following composition by mass of raw materials: 30-70 parts of liquid rubber acrylate macromonomer, 20-60 parts of free radical active diluent, 5-10 parts of crosslinking agent, 1-10 parts of photoinitiator; liquid rubber The acrylate macromonomer is obtained by reacting hydroxyl-containing liquid rubber and acryloyl chloride compounds. The present invention also provides a preparation method of the above-mentioned transparent glue. The liquid optically transparent adhesive of the present invention has the advantages of good fluidity, low odor, and short curing time; after curing, the transparency is as high as 99%, the refractive index is about 1.5, excellent yellowing resistance and acid and alkali resistance, and has good adhesion performance and flexibility. It can be widely used in touch screen displays of electronic products.

Description

A kind of liquid optically transparent glue cured by ultraviolet light and its preparation method and application

technical field

The invention relates to a UV-cured optically transparent adhesive and its preparation method and application, in particular to a new type of UV-cured liquid rubber acrylate macromonomer that does not contain microgel and has high yellowing resistance. An optically transparent adhesive belongs to the field of adhesives.

Background technique

Ultraviolet (UV) curable liquid optically clear adhesive (LOCA) is a multi-component, medium-low viscosity, high light transmittance special adhesive. Because of its simple operation process and excellent mechanical properties, it is mainly used in touch screens and liquid crystal displays. The purpose is to reduce light loss, increase contrast, and improve display effects.

Among various UV-curable liquid optically transparent adhesives, acrylate monomers have good light transmission properties, high curing activity, and a refractive index close to that of ITO conductive glass (indium tin oxide conductive glass), which has attracted people's attention. However, common acrylate monomers have disadvantages such as low viscosity, poor flexibility and high cure shrinkage. In order to solve the above problems, people have designed and synthesized acrylate macromonomers, and prepared liquid optically transparent adhesives with acrylate monomers as diluents. The currently developed acrylate macromonomers are mainly divided into three categories: one is Epoxy acrylates; the second is polyurethane acrylates; the third is liquid rubber acrylates.

(1) epoxy resin acrylate

Chinese patent document CN102925094A (application number: 201210447242.6) discloses a UV-curable adhesive suitable for ultra-low temperature environments. %～22%; epoxy resin B: 38%～47%; diluent: 10%～20%; free radical initiator: 1～3%; cationic initiator: 2～4%. However, the UV curable adhesive has high rigidity, poor toughness and unsatisfactory light transmittance after curing.

(2) Polyurethane acrylates

Chinese patent document CN103242796A (application number: 201310196382.5) discloses a UV-curable liquid optical adhesive, which is characterized in that it consists of the following components by weight: 40-70 parts of polyurethane acrylate oligomer, (methyl) 20-40 parts of acrylate, 0.1-5 parts of photoinitiator, 1-10 parts of silane coupling agent, 0-10 parts of auxiliary agent. However, because the urethane acrylate oligomer contains polyol chain segments, the UV-curable liquid optical adhesive makes the product prone to yellowing.

Chinese patent document CN103031105A (application number: 201210576234.1) discloses a UV-curable liquid optical adhesive and a preparation method thereof, belonging to the field of adhesives. Using toluene diisocyanate, polyethylene glycol and hydroxyethyl acrylate as raw materials, the polyurethane acrylate macromonomer is synthesized by bulk method and multi-step reaction; and with this macromonomer as the main body, by adding photoinitiator and compound reactive diluent And other additives to make UV-curable liquid optical glue. However, the UV-curable liquid optical adhesive is more prone to yellowing due to the benzene ring and polyethylene glycol structure contained in the product.

The liquid optically transparent adhesive of polyurethane acrylate can meet the requirements in terms of mechanical properties and optical properties, but its yellowing resistance and moisture resistance are poor.

(3) Liquid rubber acrylate

Liquid rubber has the characteristics of colorless and transparent, good light transmission performance, and no yellowing, especially in moisture barrier properties. Currently, liquid rubber-based acrylate macromonomers have become the mainstream of development.

Currently the most widely used liquid rubber acrylate macromonomer is a product called UC203 produced by Japan Kuraray Corporation. Its synthesis method is as follows: first graft maleic anhydride onto liquid polyisoprene, The reaction of ester hydroxyethyl ester is obtained, and the specific reaction equation is as follows:

The cured film obtained by using UC203 as the macromonomer and acrylate monomer as the diluent has a light transmittance as high as 99%, a hardness of only 12A-15A, a yellowing index of less than 0.5, and a refractive index of 1.5. However, since the reaction of polyisoprene grafted with maleic anhydride is a free radical polymerization reaction, cross-linking reactions between polyisoprene chains often occur, and microgel phenomenon is likely to occur.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a novel liquid optically transparent glue cured by ultraviolet light, its preparation method and application. In the present invention, liquid rubber containing hydroxyl groups is selected for esterification reaction with acryloyl chloride, free radical reaction is avoided, a new type of liquid rubber acrylate macromonomer is prepared, and a liquid optically transparent glue. Micro-crosslinking does not occur during the reaction process, and the product has high light transmittance, good toughness, and better yellowing resistance after curing.

Technical scheme of the present invention is as follows:

A novel liquid optically transparent adhesive cured by ultraviolet light, comprising the following components by mass of raw materials:

30-70 parts of liquid rubber acrylate macromonomer, 20-60 parts of free radical reactive diluent, 5-10 parts of crosslinking agent, 1-10 parts of photoinitiator;

The liquid rubber acrylate macromonomer is obtained by reacting hydroxyl-containing liquid rubber and acryloyl chloride compounds.

According to the present invention, preferably, the novel liquid optically transparent glue cured by ultraviolet light comprises the following components by mass of raw materials:

40-60 parts of liquid rubber acrylate macromonomer, 30-50 parts of free radical active diluent, 7-8 parts of crosslinking agent, and 3-7 parts of photoinitiator.

According to the present invention, preferably, said hydroxyl-containing liquid rubber is hydroxyl polybutadiene or hydroxyl polyisoprene; more preferably, said hydroxyl polybutadiene is hydroxyl-terminated polybutadiene, side hydroxyl Polybutadiene, star-shaped hydroxyl polybutadiene or a mixture of two or more, said hydroxyl-polyisoprene is hydroxyl-terminated polyisoprene, side-hydroxyl polyisoprene, star-shaped One or more than two kinds of hydroxyl polyisoprene mixed;

Preferably, the molecular weight of the hydroxyl-containing liquid rubber is 100-60000, more preferably 2000-50000, more preferably 5000-10000;

Preferably, the hydroxyl group content in the hydroxyl group-containing liquid rubber is 0.15 mmol/g-1.75 mmol/g, more preferably, the hydroxyl group content in the hydroxyl group-containing liquid rubber is 0.28-1.60 mmol/g. Hydroxyl-containing liquid rubber is commercially available, and can also be prepared by anion polymerization, living radical polymerization, free radical polymerization, coordination polymerization, etc. according to the prior art.

According to the present invention, preferably, the acryloyl chloride compound is one of acryloyl chloride, methacryloyl chloride, 2-ethylacryloyl chloride or 2-propylacryloyl chloride.

According to the present invention, preferably, the free radical reactive diluent is (meth)acrylate; further preferably, the (meth)acrylate is methyl (meth)acrylate, (meth)acrylic acid One of ethyl ester, n-butyl (meth)acrylate, isobutyl (meth)acrylate, hydroxyethyl (meth)acrylate, isobornyl (meth)acrylate or tetrahydrofurfuryl methacrylate Or a mixture of two or more.

According to the present invention, preferably, the crosslinking agent is ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate Or a mixture of one or two or more of trimethylolpropane triacrylate.

According to the present invention, preferably, the photoinitiator is benzophenone, bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2-methyl-1-[4-( Methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, 2-hydroxy-2-methyl-1-phenyl-1-propanone or 2-benzyl-2-dimethoxyamino-1-(4-morpholinephenyl)-1-butanone A sort of.

According to the present invention, the preparation method of the above-mentioned novel liquid optically transparent adhesive cured by ultraviolet light comprises the following steps:

Mix the liquid rubber acrylate macromonomer, the free radical active diluent and the crosslinking agent, stir evenly, add the photoinitiator and continue to stir until uniform and transparent, and then a new type of liquid optically transparent adhesive cured by ultraviolet light is obtained.

According to the present invention, the above-mentioned novel liquid optically transparent adhesive cured by ultraviolet light is used as an adhesive in electronic products, especially in touch screen displays.

A liquid rubber acrylate macromonomer is obtained by reacting hydroxyl-containing liquid rubber and acryloyl chloride compounds.

According to the present invention, the preparation method of above-mentioned liquid rubber acrylate macromer comprises steps as follows:

After the hydroxyl-containing liquid rubber is dehydrated, it is dissolved in a solvent, and a catalyst is added to react with acryloyl chloride compounds. After the reaction, the insoluble impurities are filtered to remove, and the filtrate is precipitated with alcohol, filtered again, washed with solids, and dried to obtain liquid rubber acrylate Large monomer.

According to the preparation method of the liquid rubber acrylate macromonomer of the present invention, preferably, the dehydration method of the hydroxyl-containing liquid rubber is: vacuum dehydration at a temperature of 100°C-120°C for 1-2 hours;

Preferably, the dissolving temperature in the solvent is 0-5°C. More preferably, the solvent is an oil-soluble solvent, more preferably benzene, toluene, tetrahydrofuran, dichloromethane, chloroform, dioxane, Dimethyl sulfoxide or N,N-dimethylformamide.

Preferably, the catalyst is a weakly basic organic or inorganic base, more preferably triethylamine or potassium carbonate;

Preferably, the reaction temperature is 40-80°C, more preferably, the reaction is stirred, the reaction time is 2-8 hours, and cooled to room temperature after the reaction;

Preferably, the alcohol described in the filtrate precipitation process with alcohol is ethanol;

Preferably, the hydroxyl liquid rubber:catalyst:acryloyl chloride compound=(50-100):(5-10):(6-15), mass ratio.

According to the present invention, the above-mentioned liquid rubber acrylate macromonomer is used in the preparation of novel liquid optically transparent glue cured by ultraviolet light.

The synthetic route of liquid rubber acrylate macromonomer of the present invention is as follows:

The present invention has the following advantages:

1. No microgel phenomenon occurs. The synthesis of the liquid rubber acrylate macromonomer of the present invention is obtained by selecting the hydroxyl-containing liquid rubber and the acryloyl chloride compound for esterification reaction, the reaction condition is mild, and the product is single. No cross-linking phenomenon will occur when it is used to prepare a new type of liquid optically clear adhesive cured by ultraviolet light, and the occurrence of microgel phenomenon is eliminated.

2. Excellent yellowing resistance. Neither the liquid rubber acrylate macromonomer nor the free radical reactive diluent of the present invention contains polyether segments and aromatic compounds that are prone to yellowing, which ensures that the new liquid optically transparent adhesive cured by ultraviolet light has better yellowing resistance transsexual.

3. Short curing time. Under the irradiation of ultraviolet light, the novel liquid optically transparent glue cured by ultraviolet light of the present invention is basically completely cured within 40-50 seconds, has short curing time and saves energy.

Description of drawings

Fig. 1 is the infrared spectrogram of double-terminated hydroxyl polybutadiene and polybutadiene acrylate macromonomer prepared in Example 1 of the present invention. Among them: a double-terminated hydroxyl polybutadiene, b polybutadiene acrylate macromonomer.

Fig. 2 is the H NMR spectrum of the polybutadiene acrylate macromonomer prepared in Example 1 of the present invention.

detailed description

The present invention will be further described below through specific examples, but not limited thereto.

The raw materials used in the examples are conventional commercially available products.

Embodiment 1, the synthesis of polybutadiene acrylate macromonomer

Add 10.0g double-terminated hydroxyl polybutadiene (molecular weight is 5000, hydroxyl content is 0.64mmol/g) in the three-necked reaction flask that thermometer is housed, vacuumize dehydration at 120 DEG C for 1.5 hours; Drop to 0 DEG C, Add 30mL of chloroform to dissolve it, blow in nitrogen, and add 1.3g of triethylamine and 1.5g of methacryloyl chloride in sequence, and fully stir at 40°C for 6 hours of reaction. After the reaction was completed, the insoluble precipitate was removed by filtration, and the filtrate was dropped into 50 mL of absolute ethanol to precipitate the product, and vacuum-dried to obtain a polybutadiene acrylate macromonomer with a yield of more than 90%.

FTIR (KBr, cm ^-1 ): 1721 (C=O), 1263, (CO), 3650 (-OH) disappeared, as shown in Fig. 1 .

¹ HNMR (300MHz, CD ₃ Cl, ppm): 6.09 (1H, C=CH ₂ ), 5.50 (1H, C=CH ₂ ), 1.70 (3H, C=C-CH ₃ ), 3.67 (CH ₂ -OH ) is significantly weakened, as shown in Figure 2.

Embodiment 2, the preparation of the novel liquid optical transparent adhesive of ultraviolet curing

In the 100mL three-necked flask equipped with a stirrer, add 10g of the polybutadiene acrylate macromonomer prepared in Example 1, 4g of methyl methacrylate, 3g of isobornyl methacrylate, and 1g of butyl methacrylate , 2g of ethylene glycol dimethacrylate, after stirring evenly, add 0.6g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone, and continue stirring until uniform and transparent, that is, UV-cured A new liquid optically clear adhesive.

Embodiment 3,

In the 100mL three-necked flask equipped with a stirrer, add 8g of polybutadiene acrylate macromonomer prepared in Example 1, 4g of methyl methacrylate, 2g of butyl methacrylate, and 3g of isobornyl methacrylate , ethylene glycol dimethacrylate 2g, 1,6-hexanediol diacrylate 1g, after stirring evenly, add photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide 0.6g, continue to stir until it is uniform and transparent, and a new type of liquid optically transparent adhesive cured by ultraviolet light is obtained.

Embodiment 4,

In the 100mL three-necked flask equipped with a stirrer, add 12g of the polybutadiene acrylate macromonomer prepared in Example 1, 2g of methyl methacrylate, 2g of butyl methacrylate, and 2g of isobornyl methacrylate , 2g of diethylene glycol dimethacrylate, after stirring evenly, add 0.6g of photoinitiator 2-hydroxyl-2-methyl-1-phenyl-1-propanone, and continue to stir until it is uniform and transparent, and the ultraviolet light Cured new liquid optically clear adhesive.

Embodiment 5,

In a 100mL three-necked flask equipped with a stirrer, add 10 g of the polybutadiene acrylate macromonomer prepared in Example 1, 3 g of methyl methacrylate, 2 g of butyl methacrylate, and 2 g of isobornyl methacrylate , hydroxyethyl methacrylate 1g, ethylene glycol dimethacrylate 2g, after stirring evenly, add photoinitiator 2-hydroxyl-2-methyl-1-phenyl-1-propanone 0.6g, continue to stir until Uniform and transparent, that is, a new type of liquid optically transparent adhesive cured by ultraviolet light.

Embodiment 6, the synthesis of polybutadiene acrylate macromonomer

Add 10.0g double-terminated hydroxyl polybutadiene (molecular weight is 8000, hydroxyl content is 0.52mmol/g) in the three-necked reaction flask that thermometer is housed, vacuumize dehydration at 120 DEG C for 2 hours; Drop to 0 DEG C, Add 30mL of chloroform to dissolve it, pass through nitrogen, and add 1.05g of potassium carbonate and 1.12g of methacryloyl chloride in sequence, and fully stir at 40°C to react for 6 hours. Sampling and measuring the infrared spectrum confirmed that the 3650cm ^-1 hydroxyl absorption peak disappeared, the carbonyl absorption peak appeared at 1721cm ^-1 , and the 1163 cm ^-1 was the CO bond absorption peak.

After the reaction was completed, the insoluble precipitate was removed by filtration, and the filtrate was added dropwise into 50 mL of absolute ethanol to precipitate the product, and dried in vacuum to obtain a polybutadiene acrylate macromonomer.

Embodiment 7,

In a 100mL three-necked flask equipped with a stirrer, add 10g of the polybutadiene acrylate macromonomer prepared in Example 6, 2g of methyl methacrylate, 3g of butyl methacrylate, and 3g of isobornyl methacrylate , ethylene glycol dimethacrylate 2g, after stirring evenly, add 0.8g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone, continue to stir until uniform and transparent, that is, UV-cured A new liquid optically clear adhesive.

Embodiment 8,

In the 100mL three-necked flask equipped with a stirrer, add 8g of polybutadiene acrylate macromonomer prepared in Example 6, 3g of ethyl methacrylate, 3g of butyl methacrylate, and 2g of isobornyl methacrylate , hydroxyethyl methacrylate 2g, ethylene glycol dimethacrylate 1g, trimethylolpropane triacrylate 1g, after stirring evenly, add photoinitiator 2-hydroxyl-2-methyl-1-phenyl - 0.6 g of 1-acetone, continue to stir until uniform and transparent, and obtain a novel liquid optically transparent adhesive cured by ultraviolet light.

Embodiment 9,

In the 100mL three-necked flask equipped with a stirrer, add 8g of polybutadiene acrylate macromonomer prepared in Example 6, 3g of ethyl methacrylate, 2g of isobutyl methacrylate, and isobornyl methacrylate 2g, 2g of hydroxyethyl methacrylate, 2g of diethylene glycol dimethacrylate, 1g of trimethylolpropane triacrylate, after stirring evenly, add the photoinitiator 2-hydroxyl-2-methyl-1- Phenyl-1-acetone 0.6g, continue to stir until uniform and transparent, and obtain a novel liquid optically transparent adhesive cured by ultraviolet light.

Embodiment 10, the synthesis of polyisoprene acrylate macromonomer

Add 10.0g of double-terminated hydroxyl polyisoprene (molecular weight: 8000, hydroxyl content: 0.48mmol/g) into a three-necked reaction flask equipped with a thermometer, vacuumize and dehydrate at 100°C for 2 hours; drop to 0°C , add 30mL of chloroform to dissolve it, pass through nitrogen, and add 1.3g of triethylamine, 1.5g of methacryloyl chloride in sequence, and fully stir at 80°C, react for 2 hours. After the reaction was completed, the insoluble precipitate was removed by filtration, and the filtrate was dropped into 50 mL of absolute ethanol to precipitate the product, and vacuum-dried to obtain a polyisoprene acrylate macromonomer with a yield of more than 90%.

Embodiment 11,

Add 10.0g star-shaped hydroxy polybutadiene (molecular weight is 8000, hydroxyl content is 1.06mmol/g) in the three-necked reaction flask that thermometer is housed, vacuumize dehydration at 110 DEG C for 2 hours; Drop to 3 DEG C, Add 30 mL of chloroform to dissolve it, blow nitrogen, and add 1.0 g of triethylamine and 1.5 g of 2-ethylacryloyl chloride in sequence, and fully stir at 50 ° C for 4 hours. After the reaction was finished, the insoluble precipitate was removed by filtration, and the filtrate was dropped into 50 mL of absolute ethanol to precipitate the product, and vacuum-dried to obtain a polybutadiene acrylate macromonomer with a yield of more than 90%.

Embodiment 12,

In a 100mL three-necked flask equipped with a stirrer, add 30g of the polyisoprene acrylate macromonomer prepared in Example 10, 20g of n-butyl (meth)acrylate, and 5g of trimethylolpropane triacrylate, After stirring evenly, add 1 g of photoinitiator benzophenone, continue stirring until uniform and transparent, and obtain a novel liquid optically transparent adhesive cured by ultraviolet light.

Embodiment 13,

In the 100mL three-necked flask equipped with a stirrer, add 70g of polybutadiene acrylate macromonomer prepared in Example 11, 60g of hydroxyethyl acrylate, and 10g of tripropylene glycol diacrylate, and stir evenly , add photoinitiator 10g of ethyl 2,4,6-trimethylbenzoylphenyl phosphonate, continue to stir until uniform and transparent, and obtain a new type of liquid optically transparent adhesive cured by ultraviolet light.

Performance testing, performance testing of new liquid optically clear adhesives cured by UV light

1. The viscosity and curing time of the new UV-cured liquid optically transparent adhesives prepared in Examples 2-5 and Examples 7-9 were respectively tested.

The viscosity test uses a rotor viscometer NDJ-8S viscometer at 25°C.

Specific implementation of curing time performance test: pour the sample into a polytetrafluoroethylene mold, place it under a UV lamp for curing, and after curing for a period of time, lightly press the coating film with your fingers. If the surface of the coating film is not sticky and does not leave Fingerprint, the sample has been cured, record the curing time, the results are shown in Table 1.

Table 1 Viscosity and curing time of new liquid optically clear adhesives cured by UV light

It can be seen from Table 1 that the novel liquid optically transparent adhesive cured by ultraviolet light of the present invention is a colorless transparent liquid with a curing time of less than 60 seconds, and has the advantages of good fluidity, low odor and short curing time.

2. Take the UV-cured novel liquid optically transparent adhesives prepared in Examples 2-5 and Examples 7-9 respectively and perform performance tests after curing;

a Spread the sample evenly on the glass plate, and test it after the patch is cured.

b In the acid and alkali resistance test, the acid solution is 1.0mol/L hydrochloric acid solution, the lye is 1.0mol/L sodium hydroxide solution, the soaking time is 24 hours, and the product is qualified if it does not turn white after soaking, the results are shown in the table 2.

Table 2 Properties of UV-cured new liquid optically clear adhesive after curing

Example 2 Example 3 Example 4 Example 5 Example 7 Example 8 Example 9 Hardness (Shore A) twenty two twenty three 18 19 20 twenty three 25 Shear strength/MPa ^a 3.9 3.8 3.5 3.7 3.9 4.1 4.2 Elongation at break% 179 186 212 205 198 169 167 Refractive index 1.50 1.51 1.50 1.51 1.50 1.50 1.49 Transmittance% 98 99 99 99 99 99 98 yellowing index <0.4 <0.4 <0.4 <0.4 <0.4 <0.4 <0.4 Acid and alkali ^resistanceb qualified qualified qualified qualified qualified qualified qualified

It can be seen from Table 2 that the UV-cured novel liquid optically transparent adhesive of the present invention has a transparency as high as 99% after curing, and its refractive index is about 1.5, which is the same as the glass shading index; the shear strength of the glass plate is about 4.0MPa, showing excellent At the same time, the Shore hardness is within 25A, the elongation at break is 200%, and it has good flexibility. The anti-yellowing index is less than 0.4, which also meets the requirements; it also has excellent acid and alkali resistance.

Claims (4)

1. A liquid optically transparent adhesive cured by ultraviolet light, comprising the composition of raw material parts by mass as follows: 30-70 parts of liquid rubber acrylate macromonomer, 20-60 parts of free radical reactive diluent, 5-10 parts of crosslinking agent, 1-10 parts of photoinitiator; The liquid rubber acrylate macromonomer is obtained by reacting hydroxyl-containing liquid rubber and acryloyl chloride compounds, and the steps are as follows: Add 10.0 g of double-terminated hydroxyl polybutadiene into a three-necked reaction flask equipped with a thermometer, with a molecular weight of 5000 and a hydroxyl content of 0.64 mmol/g, vacuum dehydration at a temperature of 120 ° C for 1.5 hours; drop to 0 ° C, add Dissolve it in 30mL of chloroform, blow nitrogen, and add 1.3g of triethylamine and 1.5g of methacryloyl chloride in sequence, and fully stir at 40°C, and react for 6 hours; Drop into 50mL of absolute ethanol to precipitate the product, and dry it in vacuum to obtain polybutadiene acrylate macromonomer; Alternatively, add 10.0 g of double-terminated hydroxyl polybutadiene in a three-necked reaction flask equipped with a thermometer, with a molecular weight of 8000 and a hydroxyl content of 0.52 mmol/g, and vacuum dehydrate at a temperature of 120 ° C for 2 hours; drop to 0 ° C , add 30mL of chloroform to dissolve it, pass through nitrogen, and add 1.05g of potassium carbonate and 1.12g of methacryloyl chloride in sequence, and fully stir at 40°C, react for 6 hours; filter to remove insoluble precipitate after the reaction, and The filtrate was added dropwise to 50 mL of absolute ethanol to precipitate the product, and dried in vacuo to obtain a polybutadiene acrylate macromonomer; Alternatively, add 10.0 g of double-terminated hydroxyl polyisoprene with a molecular weight of 8000 and a hydroxyl content of 0.48 mmol/g into a three-necked reaction flask equipped with a thermometer, and vacuum dehydrate at a temperature of 100 ° C for 2 hours; ℃, add 30mL chloroform to dissolve it, pass nitrogen gas, and add 1.3g triethylamine and 1.5g methacryloyl chloride in sequence, and fully stir at 80℃, react for 2 hours; filter to remove insoluble precipitate after the reaction, And the filtrate was dropped into 50mL of absolute ethanol to precipitate the product, and vacuum-dried to obtain a polyisoprene acrylate macromonomer; The free radical active diluent is methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, hydroxyethyl (meth)acrylate One or more mixtures of esters, isobornyl (meth)acrylate or tetrahydrofurfuryl methacrylate; The cross-linking agent is ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate or trimethylolpropane trimethacrylate One or more than two kinds of acrylates mixed; The photoinitiator is benzophenone, bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2-methyl-1-[4-(methylthio)phenyl ]-2-(4-morpholino)-1-propanone, 1-hydroxycyclohexyl phenyl ketone, ethyl 2,4,6-trimethylbenzoylphenyl phosphonate, 2-hydroxy-2 - one of methyl-1-phenyl-1-propanone or 2-benzyl-2-dimethoxyamino-1-(4-morpholinephenyl)-1-butanone. 2. The liquid optically transparent glue cured by ultraviolet light according to claim 1, is characterized in that, comprises the composition of raw material mass parts as follows: 40-60 parts of liquid rubber acrylate macromonomer, 30-50 parts of free radical active diluent, 7-8 parts of crosslinking agent, and 3-7 parts of photoinitiator. 3. A preparation method of the liquid optically transparent adhesive cured by ultraviolet light according to any one of claims 1-2, comprising the following steps: Mix the liquid rubber acrylate macromonomer, the free radical active diluent and the crosslinking agent, stir evenly, add the photoinitiator and continue stirring until uniform and transparent, and obtain the liquid optically transparent adhesive cured by ultraviolet light. 4. The application of the liquid optically transparent glue cured by ultraviolet light according to any one of claims 1-2 as an adhesive in a touch screen display.