Acrylic adhesive and preparation method thereof

Abstract

The invention discloses an acrylic adhesive and a preparation method thereof. The acrylic adhesive comprises the following raw materials: 70-90 parts of an acrylic monomer; the modified component is selected from polyethylene glycol with the molecular weight of 2000 to 3000, polypropylene glycol with the molecular weight of 2000 to 3000 or epoxy resin with the epoxy equivalent of 184 to 194 g / eq; 1-10 parts of an aldehyde component, wherein the aldehyde component is selected from one or more of cinnamyl aldehyde, p-hydroxycinnamaldehyde, vanillin and dihydrosinalaldehyde; 0.1 to 0.5 part of an initiator; 50 to 150 parts of a solvent; optionally, 0.3 to 1.0 part of an antistatic agent is also contained. The acrylic adhesive disclosed by the invention is relatively good in overall bending strength; the adhesive has strong high temperature resistance, no adhesive residue is left on a stainless steel plate after the stainless steel plate is cooled to room temperature after high temperature, and the adhesive is small in stripping force change and easy to strip after high temperature; and after being cured, the adhesive is high in transparency and low in haze.

Description

Technical Field

[0001] The invention relates to the field of adhesives, and in particular to an acrylic adhesive and a preparation method thereof. Background Art

[0002] Acrylic glue is a common adhesive, usually polymerized from acrylic ester monomers, with excellent bonding properties and weather resistance, and is widely used. In recent years, with the continuous advancement of science and technology, people have higher and higher requirements for the performance of adhesives, especially in special environments. Therefore, modifying acrylic glue to improve its performance has become one of the research hotspots.

[0003] The physical properties of acrylic glue are colorless, transparent, easy to flow, non-flammable, volatile, and aromatic liquid. It should be stored in a cool, ventilated warehouse, away from fire and heat sources. It is also called organic glass glue, which is a solvent-based adhesive. It achieves bonding by dissolving and completely evaporating the solvent. However, the acrylic glue on the market has weak toughness and is easily affected by the environment such as light. It is easy to burst or crack after being placed for a long time. Benzene and dichloromethane are often used in the production process. Dichloromethane, toluene and xylene are all restricted solvents in "GB 18583-2008 Limits of Hazardous Substances in Adhesives for Indoor Decoration and Renovation Materials", which have a greater impact on the environment. In addition, the addition of other additives will affect the transparency of acrylic glue.

[0004] Therefore, providing a technical means to solve the defects of acrylic glue such as toughness and easy cracking, while ensuring its beauty and transparency, is a technical problem that needs to be solved urgently. Summary of the invention

[0005] To achieve the above object, the present invention provides an acrylic adhesive and a preparation method thereof.

[0006] The present invention provides an acrylic adhesive, the raw materials of which include:

[0007] 70-90 parts of acrylic acid monomer;

[0008] 1-10 parts of a modifying component, wherein the modifying component is selected from polyethylene glycol with a molecular weight of 2000-3000, polypropylene glycol with a molecular weight of 2000-3000, or an epoxy resin with an epoxy equivalent of 184-194 g / eq;

[0009] 1-10 parts of aldehyde components, wherein the aldehyde components are selected from one or more of cinnamaldehyde, p-hydroxycinnamaldehyde, vanillin, and dihydrosinapine aldehyde;

[0010] 0.1-0.5 parts of initiator;

[0011] 50-150 parts of solvent;

[0012] Optionally, 0.3-1.0 parts of an antistatic agent is also contained.

[0013] In a preferred embodiment of the present invention, the acrylic monomer is methyl acrylate, ethyl acrylate, isobutyl acrylate, isooctyl acrylate or n-butyl acrylate.

[0014] In a preferred embodiment of the present invention, the acrylic acid monomer accounts for 75-90 parts, such as 75 parts, 80 parts, 85 parts or 90 parts.

[0015] In a preferred embodiment of the present invention, the modifying component is selected from polyethylene glycol with a molecular weight of 2000 or 3000.

[0016] In a preferred embodiment of the present invention, the modifying component is selected from polypropylene glycol with a molecular weight of 2000 or 3000.

[0017] In a preferred embodiment of the present invention, the modified component is selected from epoxy resin having an average molecular weight of 375.86 and an epoxy equivalent of 184 to 194 g / eq.

[0018] In the present invention, the epoxy resin can be purchased from E51 glycidyl ether epoxy resin of Baling Petrochemical, model CYD-128.

[0019] In a preferred embodiment of the present invention, the amount of the modifying component is 4-8 parts, such as 4 parts, 5 parts, 6 parts, 7 parts or 8 parts.

[0020] In a preferred embodiment of the present invention, the aldehyde component is selected from cinnamaldehyde, p-hydroxycinnamaldehyde, vanillin or dihydrosinapine aldehyde.

[0021] In a preferred embodiment of the present invention, the aldehyde component is present in an amount of 4-8 parts, such as 4 parts, 5 parts, 6 parts, 7 parts or 8 parts.

[0022] In a preferred embodiment of the present invention, the initiator is one or more combinations of azobisisobutyronitrile, dibenzoyl peroxide, dodecanoyl peroxide, benzoyl peroxide and azobisisoheptanenitrile.

[0023] In a preferred embodiment of the present invention, the amount of the initiator is 0.2-0.5 parts, for example 0.3 parts.

[0024] In a preferred embodiment of the present invention, the antistatic agent is one or more combinations of Cyastat LS, Cyast 609 and Cyastat SP.

[0025] In a preferred embodiment of the present invention, the amount of the antistatic agent is 0.3-0.7 parts, for example 0.5 parts.

[0026] The present invention also provides a method for preparing the acrylic adhesive, comprising the following steps:

[0027] S1, sequentially adding the acrylic monomer, the modified component and the aldehyde component into a reaction container 1, stirring them evenly to obtain a mixture A;

[0028] S2, add 5-15% by weight of the mixture A and 20-30% by weight of the solvent in the reaction container 2, stir evenly and heat to 70-80°C, then slowly drop 20-30% by weight of the initiator into the reaction solution for 0.5-1h, then keep the temperature at 70-80°C for 1-2h to obtain a mixture B;

[0029] S3, add the remaining mixed material A, 40-60% by weight of the solvent and 20-30% by weight of the initiator to the reaction container 3 in sequence, stir evenly and then slowly add to the mixed material B dropwise for 2-4 hours, then keep warm at 70-80°C for 0.2-0.4 hours to obtain a mixed material C;

[0030] S4, adding the remaining initiator and solvent to the mixed material C in sequence, heating to 80-90° C., and reacting for 1-3 hours; after the reaction is completed, cooling the reaction liquid to 20-30° C., adding the antistatic agent, stirring the reaction for 10-30 minutes, and then discharging the material to obtain the acrylic adhesive.

[0031] The reagents and raw materials used in the present invention are commercially available.

[0032] The positive and progressive effects of the present invention are:

[0033] The overall bending strength of the acrylic adhesive in the present invention is good; the adhesive has strong high temperature resistance, and there is no residual adhesive when peeled off from the stainless steel plate after cooling to room temperature after high temperature, and the peeling force changes little after high temperature, and it is easy to peel off; after the adhesive is cured, it has high transparency and low haze. DETAILED DESCRIPTION

[0034] 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.

[0035] In the following examples and comparative examples, the sources of the raw materials are as follows:

[0036] PEG1000: polyethylene glycol, a bifunctional polyether with a molecular weight of 1000;

[0037] PEG2000: polyethylene glycol, a bifunctional polyether with a molecular weight of 2000;

[0038] PEG3000: polyethylene glycol, a bifunctional polyether with a molecular weight of 3000;

[0039] PEG4000: polyethylene glycol, a bifunctional polyether with a molecular weight of 4000;

[0040] PPG1000: polypropylene glycol, difunctional polyether with molecular weight of 1000;

[0041] PPG2000: polypropylene glycol, difunctional polyether with molecular weight of 2000;

[0042] PPG3000: polypropylene glycol, bifunctional polyether with molecular weight of 3000;

[0043] PPG4000: polypropylene glycol, difunctional polyether with molecular weight of 4000;

[0044] Epoxy resin: E51 glycidyl ether epoxy resin purchased from Baling Petrochemical, model CYD-128; its average molecular weight is 375.86, and the epoxy equivalent is 184-194 g / eq.

[0045] Examples 1-5

[0046] The acrylic adhesives in Examples 1-5 are formulated in parts by weight as shown in Table 1 below.

[0047] Table 1

[0048]

[0049] According to the formula shown in Table 1, the preparation method is as follows:

[0050] S1, adding acrylic acid, a modifying component, and an aldehyde into a reaction container 1 in sequence, and stirring them evenly to obtain a mixture A;

[0051] S2, 5% by weight of the mixture A and 50 parts by weight of the solvent were added to the reaction container 2 in sequence, stirred evenly, and the mixture was heated to 70° C., and then 0.06 parts of azobisisobutyronitrile were slowly added dropwise to the mixture for 0.5 h, and the mixture was kept at 70° C. for 1 h to obtain a mixture B;

[0052] S3, in reaction vessel 3, the remaining mixed material A, 40 parts of solvent and 0.06 parts of azobisisobutyronitrile are mixed in sequence and then slowly added dropwise to mixed material B for 2 hours, and the mixture is kept at 70° C. for 0.2 hours to obtain mixed material C;

[0053] S4, adding the remaining azobisisobutyronitrile and the remaining solvent into the mixture C, heating to 80°C, and reacting for 1 hour; after the reaction is completed, cooling the reaction liquid to 20°C, adding an antistatic agent, stirring the reaction for 10 minutes, and then discharging the material to obtain an acrylic adhesive.

[0054] Comparative Example 1

[0055] Except that the type of the modified component is PEG1000, other conditions are the same as those in Example 3.

[0056] Comparative Example 2

[0057] Except that the type of the modified component is PEG4000, other conditions are the same as those in Example 3.

[0058] Comparative Example 3

[0059] Except that the type of modified component is PPG1000, other conditions are the same as those in Example 3.

[0060] Comparative Example 4

[0061] Except that the type of the modified component is PPG4000, other conditions are the same as those in Example 3.

[0062] Effect Example 1

[0063] Weigh 100 parts of the acrylic adhesive in Examples 1-5 and Comparative Examples 1-4, 1.4 parts of a curing agent (isocyanate), and 34 parts of ethyl acetate as a solvent; add ethyl acetate to the curing agent to obtain a curing agent solution; add the curing agent solution to the acrylic adhesive, mix and stir evenly to obtain a mixed solution;

[0064] The obtained mixed solution was coated on an acrylic adhesive sample (length 15 mm, width 10 mm, height 30 mm), the test area was 15 mm × 10 mm, the mixed solution thickness was 23-27 μm, and it was cured at room temperature for 3 days, and then placed in a xenon lamp aging test box for aging, the xenon arc lamp was 162 W / m 2 .

[0065] The sample was bent on a universal testing machine with a span of 40 mm to obtain the bending strength. The bending strength was tested before xenon lamp aging, and after xenon lamp aging for 33h, 98h, 196h, 294h, 400h, 1176h and 1968h. Three groups of parallel samples were tested at each aging time. The bending strength test was carried out at room temperature of 22±1℃.

[0066] The test results are shown in Table 2.

[0067] Table 2

[0068]

[0069] Effect Example 2

[0070] Application in PET protective film: The mixed solution of the curing agent solution and the acrylic adhesive in Example 1 is evenly coated on the corona surface of a PET base film with a thickness of 50 μm, and is placed in a 90°C oven for 3 min until the adhesive surface is completely dry, and the dry adhesive thickness is controlled to be 9 μm; then, a release film with a thickness of 50 μm is covered on the adhesive surface to protect the adhesive surface, and it is placed in a 50°C oven for curing for 3 days.

[0071] Performance Test:

[0072] (1) PET protective film peeling force test: According to the GB 2792-1998 standard test method, the PET protective film with adhesive surface is attached to the SU304 stainless steel plate and soaked for 30 minutes. The test conditions are 23±2°C and humidity is 65±5%. The peeling force of the stainless steel plate in the 180° direction is measured in gf / 25mm. In addition, the peeling force is tested in an oven at 180°C for 1h and after cooling to room temperature. The results are shown in Table 3.

[0073] (2) Heat resistance test: A 25 mm wide PET protective film was cut and attached to a glass plate, and then placed in an oven and baked at 180°C for 3 h and 210°C for 1 h. After cooling to room temperature, the film was torn off and checked for any residual adhesive on the glass plate. The results are shown in Table 3.

[0074] (3) Haze: Haze transmission meter: BYK. After the equipment is calibrated, the release film of the sample is removed, and the sample is placed facing the test port on the right. The test button is pressed and the reading is recorded. The results are shown in Table 4.

[0075] Table 3

[0076]

[0077] Table 4

[0078]

Claims

1. An acrylic adhesive, characterized in that: Its raw materials include: 70-90 parts of acrylic acid monomer; 1-10 parts of a modifying component, wherein the modifying component is selected from polyethylene glycol with a molecular weight of 2000-3000, polypropylene glycol with a molecular weight of 2000-3000, or an epoxy resin with an epoxy equivalent of 184-194 g / eq; 1-10 parts of aldehyde components, wherein the aldehyde components are selected from one or more of cinnamaldehyde, p-hydroxycinnamaldehyde, vanillin, and dihydrosinapine aldehyde; 0.1-0.5 parts of initiator; 50-150 parts of solvent; Optionally, 0.3-1.0 parts of an antistatic agent is also contained.

2. The acrylic adhesive according to claim 1, characterized in that: The acrylic acid monomer is methyl acrylate, ethyl acrylate, isobutyl acrylate, isooctyl acrylate or n-butyl acrylate; And / or, the acrylic acid monomer accounts for 75-90 parts.

3. The acrylic adhesive according to claim 1, characterized in that: The acrylic monomer is present in an amount of 75 parts, 80 parts, 85 parts or 90 parts.

4. The acrylic adhesive according to claim 1, characterized in that: The modifying component is selected from polyethylene glycol with a molecular weight of 2000 or 3000; and / or, the modifying component is selected from polypropylene glycol with a molecular weight of 2000 or 3000; And / or, the modified component is selected from epoxy resin having an average molecular weight of 375.86 and an epoxy equivalent of 184 to 194 g / eq; And / or, the amount of the modifying component is 4-8 parts.

5. The acrylic adhesive according to claim 1, characterized in that: The amount of the modifying component is 4 parts, 5 parts, 6 parts, 7 parts or 8 parts.

6. The acrylic adhesive according to claim 1, characterized in that: The aldehyde component is selected from cinnamaldehyde, p-hydroxycinnamaldehyde, vanillin or dihydrosinapine aldehyde; And / or, the aldehyde component is present in an amount of 4-8 parts.

7. The acrylic adhesive according to claim 1, characterized in that: The amount of the aldehyde component is 4 parts, 5 parts, 6 parts, 7 parts or 8 parts.

8. The acrylic adhesive according to claim 1, characterized in that: The initiator is one or more combinations of azobisisobutyronitrile, dibenzoyl peroxide, dodecyl peroxide, benzoyl peroxide and azobisisoheptylnitrile; And / or, the initiator is present in an amount of 0.2-0.5 parts, such as 0.3 parts; And / or, the antistatic agent is one or more combinations of Cyastat LS, Cyast 609 and Cyastat SP; And / or, the amount of the antistatic agent is 0.3-0.7 parts, for example 0.5 parts.

9. The acrylic adhesive according to claim 1, characterized in that: The initiator is present in 0.3 parts; And / or, the amount of the antistatic agent is 0.5 part.

10. A method for preparing an acrylic adhesive as claimed in any one of claims 1 to 9, characterized in that: It includes the following steps: S1, sequentially adding the acrylic monomer, the modified component and the aldehyde component into a reaction container 1, stirring them evenly to obtain a mixture A; S2, add 5-15% by weight of the mixture A and 20-30% by weight of the solvent in the reaction container 2, stir evenly and heat to 70-80°C, then slowly drop 20-30% by weight of the initiator into the reaction solution for 0.5-1h, then keep the temperature at 70-80°C for 1-2h to obtain a mixture B; S3, add the remaining mixed material A, 40-60% by weight of the solvent and 20-30% by weight of the initiator to the reaction container 3 in sequence, stir evenly and then slowly add to the mixed material B dropwise for 2-4 hours, then keep warm at 70-80°C for 0.2-0.4 hours to obtain a mixed material C; S4, adding the remaining initiator and solvent to the mixed material C in sequence, heating to 80-90° C., and reacting for 1-3 hours; after the reaction is completed, cooling the reaction liquid to 20-30° C., adding the antistatic agent, stirring the reaction for 10-30 minutes, and then discharging the material to obtain the acrylic adhesive.

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