UV-curable solvent-free pressure-sensitive adhesive and preparation method thereof

Abstract

The invention discloses a UV-curable solvent-free pressure-sensitive adhesive and a preparation method thereof. The preparation method of the UV-curable solvent-free pressure-sensitive adhesive is characterized in that the UV-curable solvent-free pressure-sensitive adhesive comprises the following raw material components in parts by weight: 5-10 parts of methyl vinyl silicone rubber with the vinyl content of 0.17-0.23 mol%; 1 to 1.5 parts of hydrogen-containing silicone oil, wherein the hydrogen content of the hydrogen-containing silicone oil is 0.36 to 1.0 mol%; 5 to 10 parts of diisocyanate; 0.05 to 0.5 part of a catalyst; 5 to 10 parts of hydroxyethyl acrylate; 80 to 100 parts of 2-ethylhexyl acrylate; 20 to 40 parts of butyl acrylate; 5-10 parts of acrylic acid; and 1-4 parts of a photoinitiator. The pressure-sensitive adhesive modified by using the methyl vinyl silicone rubber and the hydrogen-containing silicone oil is high in initial adhesion and long in retention time, and can still keep relatively good adhesion at extreme temperature.

Description

Technical Field

[0001] The invention relates to the field of adhesives, and in particular to a UV-curable solvent-free pressure-sensitive adhesive and a preparation method thereof. Background Art

[0002] Pressure sensitive adhesive (PSA) is an adhesive that only requires a small amount of pressure to achieve good bonding performance, and after peeling, no residual colloid will contaminate the bonded material. This adhesive can be bonded at room temperature without solvent evaporation or chemical reaction, which makes the application of PSA particularly easy and safe. According to the classification of monomer materials, PSA is mainly divided into: polyurethane PSA, acrylate PSA, silicone PSA and epoxy resin PSA. Among them, acrylate PSA is the most important and widely used type of PSA, with the advantages of many types of synthetic monomers, high transparency and good aging resistance.

[0003] Solvents are generally added in the preparation process of traditional acrylic pressure-sensitive adhesives. Although the addition of solvents can improve processing performance (such as adjusting viscosity and facilitating coating), the volatilization of solvents can easily cause the adhesive layer to shrink, easily form microcracks or pores, and reduce bonding strength and temperature resistance. In addition, uneven volatilization of solvents may also cause surface wrinkles or "orange peel" phenomenon, affecting appearance and sealing.

[0004] Therefore, how to provide a UV-curable solvent-free pressure-sensitive adhesive with good bonding strength and temperature resistance is a technical problem to be solved urgently in the art. Summary of the invention

[0005] To achieve the above object, the present invention provides a UV-curable solvent-free pressure-sensitive adhesive and a preparation method thereof.

[0006] The present invention provides a method for preparing a UV-curable solvent-free pressure-sensitive adhesive, wherein the raw materials include the following components in parts by weight:

[0007] Methyl vinyl silicone rubber: 5-10 parts, wherein the vinyl content of the methyl vinyl silicone rubber is 0.17-0.23 mol%;

[0008] Hydrogen-containing silicone oil: 1-1.5 parts, wherein the hydrogen content of the hydrogen-containing silicone oil is 0.36-1.0 mol%;

[0009] Diisocyanate: 5-10 parts;

[0010] Catalyst: 0.05-0.5 parts;

[0011] Hydroxyethyl acrylate: 5-10 parts;

[0012] Isooctyl acrylate: 80-100 parts;

[0013] Butyl acrylate: 20-40 parts;

[0014] Acrylic acid: 5-10 parts;

[0015] Photoinitiator: 1-4 parts;

[0016] The preparation method of the UV-curable solvent-free pressure-sensitive adhesive comprises the following steps:

[0017] Step 1: Mix methyl vinyl silicone rubber, hydrogenated silicone oil, diisocyanate, catalyst and solvent, and stir to react at 40-60° C. for 1-3 hours to obtain mixture 1;

[0018] Step 2: Mix the mixture 1 in step 1 and hydroxyethyl acrylate, and stir the mixture at 40-80° C. for 2-6 hours to obtain a mixture 2;

[0019] Step 3: Mix the mixture 2 in step 2 with isooctyl acrylate, butyl acrylate, acrylic acid and a photoinitiator, isolate oxygen for UV curing, and dry to obtain the UV-curable solvent-free pressure-sensitive adhesive.

[0020] In the present invention, the vinyl content in the methyl vinyl silicone rubber refers to the molar percentage, and the molar percentage of vinyl refers to the number of moles of vinyl in every 100 moles of methyl vinyl silicone rubber.

[0021] In the present invention, the hydrogen content in the hydrogen-containing silicone oil refers to the mole percentage, and the mole percentage of hydrogen content refers to the number of moles of hydrogen in every 100 moles of the hydrogen-containing silicone oil.

[0022] In a preferred embodiment of the present invention, the proportion of the methyl vinyl silicone rubber is 6-10 parts, such as 6 parts, 7 parts or 10 parts.

[0023] In a preferred embodiment of the present invention, the weight average molecular weight of the methyl vinyl silicone rubber is 10000-80000 g / mol, for example, 50000 g / mol.

[0024] In a preferred embodiment of the present invention, the vinyl content of the methyl vinyl silicone rubber is 0.17 mol % or 0.23 mol %.

[0025] In a preferred embodiment of the present invention, the methyl vinyl silicone rubber is purchased from Dongjue Silicone Group Co., Ltd.

[0026] In a preferred embodiment of the present invention, the amount of the hydrogen-containing silicone oil is 1 part or 1.5 parts.

[0027] In a preferred embodiment of the present invention, the hydrogen content of the hydrogen-containing silicone oil is 0.5-1.0 mol%, for example, 0.36 mol%, 0.5 mol%, 0.75 mol% or 1.0 mol%.

[0028] In a preferred embodiment of the present invention, the diisocyanate is isophorone diisocyanate.

[0029] In a preferred embodiment of the present invention, the diisocyanate is present in an amount of 5-8 parts, such as 5 parts, 6 parts, 7 parts or 8 parts.

[0030] In a preferred embodiment of the present invention, the amount of the catalyst is 0.1 part.

[0031] In a preferred embodiment of the present invention, the catalyst is dibutyltin dilaurate.

[0032] In a preferred embodiment of the present invention, the amount of hydroxyethyl acrylate is 6-8 parts, such as 6 parts, 7 parts or 8 parts.

[0033] In a preferred embodiment of the present invention, the amount of isooctyl acrylate is 80 parts, 90 parts or 100 parts.

[0034] In a preferred embodiment of the present invention, the amount of butyl acrylate is 25-40 parts, for example, 25 parts, 30 parts or 40 parts.

[0035] In a preferred embodiment of the present invention, the amount of acrylic acid is 7-10 parts, such as 7 parts, 8 parts or 10 parts.

[0036] In a preferred embodiment of the present invention, the photoinitiator is present in an amount of 1-3 parts, for example, 2 parts.

[0037] In a preferred embodiment of the present invention, the type of the photoinitiator is photoinitiator 6976, photoinitiator 1173, photoinitiator 184 or photoinitiator 907.

[0038] In a preferred embodiment of the present invention, the reaction temperature in step 1 is 50°C.

[0039] In a preferred embodiment of the present invention, the reaction time in step 1 is 2 hours.

[0040] In a preferred embodiment of the present invention, the reaction temperature in step 2 is 60°C.

[0041] In a preferred embodiment of the present invention, the reaction time in step 2 is 4 hours.

[0042] The invention also provides a UV-curable solvent-free pressure-sensitive adhesive, which is prepared by the method.

[0043] The reagents and raw materials used in the present invention are commercially available.

[0044] The positive and progressive effects of the present invention are:

[0045] The pressure-sensitive adhesive modified with methyl vinyl silicone rubber and hydrogenated silicone oil in the present invention has high initial adhesion and long retention time, and the 180° peeling strength of the PP plate at 25°C can reach up to 42N / 25mm, and can still maintain good adhesion at extreme temperatures. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the following examples and comparative examples, the full names and English abbreviations of the raw materials are as follows:

[0048] Methyl vinyl silicone rubber, relative molecular weight 50000 g / mol, purchased from Dongjue Silicone Group Co., Ltd.;

[0049] Hydrogen-containing silicone oil: hydrogen content 0.18-1.6 mol%, purchased from Guangdong Guiye New Material Technology Co., Ltd.;

[0050] Isophorone diisocyanate, referred to as IPDI;

[0051] Dibutyltin dilaurate, referred to as DBTL;

[0052] Hydroxyethyl acrylate, referred to as HEA;

[0053] Isooctyl acrylate, referred to as 2-EHA;

[0054] Butyl acrylate, referred to as BA;

[0055] Acrylic acid, referred to as AA;

[0056] (4-phenylthio)phenyl diphenyl sulfide, photoinitiator 6976, its chemical formula is usually abbreviated as Ar3S + SbF6 - ;

[0057] Photoinitiator 1173;

[0058] Photoinitiator 184;

[0059] Photoinitiator 907.

[0060] Examples 1-4, Comparative Examples 1-3

[0061] The UV-curable solvent-free pressure-sensitive adhesives in Examples 1-4 and Comparative Examples 1-3 have formulations and process conditions calculated by weight as shown in Table 1 below.

[0062] Table 1

[0063]

[0064]

[0065] According to the formula shown in Table 1, the preparation method of UV-curable solvent-free acrylic pressure-sensitive adhesive is as follows:

[0066] Step 1: After methyl vinyl silicone rubber, hydrogenated silicone oil and IPDI are stirred and mixed uniformly under a nitrogen atmosphere, DBTL is added, and the mixture is stirred and reacted at 50° C. for 2 h to obtain a mixture 1;

[0067] Step 2: Mix the mixture 1 in step 1 and HEA, and stir the mixture at 60° C. for 4 h to obtain a mixture 2;

[0068] Step 3: Evenly mix the mixture 2 in step 2 and 2-EHA, BA, AA and the photoinitiator, isolate oxygen for UV curing, and dry to obtain a UV-curable solvent-free acrylic pressure-sensitive adhesive.

[0069] Comparative Example 1

[0070] Except that the vinyl content of the methyl vinyl silicone rubber is 0.10 mol%, other conditions are the same as those in Example 1.

[0071] Comparative Example 2

[0072] Except that the vinyl content of the methyl vinyl silicone rubber was 0.40 mol%, other conditions were the same as those in Example 1.

[0073] Comparative Example 3

[0074] Except that the hydrogen content of the hydrogen-containing silicone oil is 0.18 mol%, other conditions are the same as those in Example 1.

[0075] Comparative Example 4

[0076] Except that the hydrogen content of the hydrogen-containing silicone oil is 1.6 mol%, other conditions are the same as those in Example 1.

[0077] Effect Example 1

[0078] The UV-curable solvent-free acrylic pressure-sensitive adhesive samples in Examples 1-4 and Comparative Examples 1-4 were cut into strips for storage, and the initial adhesion, retention, and 180° peel strength tests were performed on the samples in turn using a universal tensile testing machine and a constant temperature tape retention testing machine in accordance with GB / T31125-2014, GB / T 4851-2002, and GB / T 2792-2014 standards, respectively.

[0079] The specific results are shown in Table 2.

[0080] Table 2

[0081]

[0082] As can be seen from Table 2, the pressure-sensitive adhesive modified with methyl vinyl silicone rubber and hydrogenated silicone oil has high initial adhesion and long retention time. The 180° peel strength against PP board at 25°C can reach up to 42N / 25mm, and it can still maintain good adhesion at extreme temperatures.

Claims

1. A method for preparing a UV-curable solvent-free pressure-sensitive adhesive, characterized in that: The raw materials include the following components by weight: Methyl vinyl silicone rubber: 5-10 parts, wherein the vinyl content of the methyl vinyl silicone rubber is 0.17-0.23 mol%; Hydrogen-containing silicone oil: 1-1.5 parts, wherein the hydrogen content of the hydrogen-containing silicone oil is 0.36-1.0 mol%; Diisocyanate: 5-10 parts; Catalyst: 0.05-0.5 parts; Hydroxyethyl acrylate: 5-10 parts; Isooctyl acrylate: 80-100 parts; Butyl acrylate: 20-40 parts; Acrylic acid: 5-10 parts; Photoinitiator: 1-4 parts; The preparation method of the UV-curable solvent-free pressure-sensitive adhesive comprises the following steps: Step 1: Mix methyl vinyl silicone rubber, hydrogenated silicone oil, diisocyanate, catalyst and solvent, and stir to react at 40-60° C. for 1-3 hours to obtain mixture 1; Step 2: Mix the mixture 1 in step 1 and hydroxyethyl acrylate, and stir the mixture at 40-80° C. for 2-6 hours to obtain a mixture 2; Step 3: Mix the mixture 2 in step 2 with isooctyl acrylate, butyl acrylate, acrylic acid and a photoinitiator, isolate oxygen for UV curing, and dry to obtain the UV-curable solvent-free pressure-sensitive adhesive.

2. The method for preparing a UV-curable solvent-free pressure-sensitive adhesive according to claim 1, characterized in that: The amount of the methyl vinyl silicone rubber is 6-10 parts, for example 6 parts, 7 parts or 10 parts; And / or, the weight average molecular weight of the methyl vinyl silicone rubber is 10000-80000 g / mol, for example 50000 g / mol; And / or, the vinyl content of the methyl vinyl silicone rubber is 0.17 mol % or 0.23 mol %.

3. The method for preparing a UV-curable solvent-free pressure-sensitive adhesive according to claim 1, characterized in that: The amount of the hydrogen-containing silicone oil is 1 part or 1.5 parts; And / or, the hydrogen content of the hydrogen-containing silicone oil is 0.36 mol%, 0.5 mol%, 0.75 mol% or 1.0 mol%.

4. The method for preparing a UV-curable solvent-free pressure-sensitive adhesive according to claim 1, characterized in that: The diisocyanate is isophorone diisocyanate; and / or, the diisocyanate is present in an amount of 5 to 8 parts, such as 5 parts, 6 parts, 7 parts or 8 parts; And / or, the catalyst is present in an amount of 0.1 parts; And / or, the catalyst is dibutyltin dilaurate.

5. The method for preparing a UV-curable solvent-free pressure-sensitive adhesive according to claim 1, characterized in that: The amount of hydroxyethyl acrylate is 6-8 parts, for example 6 parts, 7 parts or 8 parts.

6. The method for preparing a UV-curable solvent-free pressure-sensitive adhesive according to claim 1, characterized in that: The amount of isooctyl acrylate is 80 parts, 90 parts or 100 parts.

7. The method for preparing a UV-curable solvent-free pressure-sensitive adhesive according to claim 1, characterized in that: The amount of butyl acrylate is 25-40 parts, such as 25 parts, 30 parts or 40 parts; And / or, the acrylic acid accounts for 7-10 parts, such as 7 parts, 8 parts or 10 parts.

8. The method for preparing a UV-curable solvent-free pressure-sensitive adhesive according to claim 1, characterized in that: The photoinitiator is present in an amount of 1 to 3 parts, for example 2 parts; And / or, the type of the photoinitiator is photoinitiator 6976, photoinitiator 1173, photoinitiator 184 or photoinitiator 907.

9. The method for preparing a UV-curable solvent-free pressure-sensitive adhesive according to any one of claims 1 to 8, characterized in that: The reaction temperature in step 1 is 50°C; And / or, the reaction time in step 1 is 2h; And / or, the reaction temperature in step 2 is 60°C; And / or, the reaction time in step 2 is 4 hours.

10. A UV-curable solvent-free pressure-sensitive adhesive, which is prepared by the preparation method of the UV-curable solvent-free pressure-sensitive adhesive according to any one of claims 1 to 9.

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