Sweat-absorbent acrylic adhesive and preparation method thereof

Abstract

The invention discloses a sweat-absorbent acrylic adhesive and a preparation method thereof. The sweat-absorbent acrylic adhesive is prepared from the following raw materials: 60 to 90 parts of acrylic ester; 40-60 parts of acrylate, wherein the acrylate is selected from magnesium acrylate and / or calcium acrylate; 10 to 20 parts of polyvinyl alcohol, wherein the weight-average molecular weight of the polyvinyl alcohol is 50000 to 90000; 0.1 to 1.0 part of an initiator; and 50 to 150 parts of a solvent. The acrylic adhesive disclosed by the invention has excellent water absorption and water retention properties, and is high in adhesive force and good in high-temperature resistance.

Description

Technical Field

[0001] The invention relates to the field of adhesives, and in particular to a sweat-absorbing 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] Acrylic adhesive has excellent adhesion to human skin, so it has been used in medical tapes for a long time, and can achieve good adhesion. The tape can be tightly attached to the human skin and is not easy to fall off. However, acrylic adhesives are not hydrophilic. If the skin sweats, the sweat will be wrapped between the film and the skin and cannot be eliminated. This will cause the tape to debond or lose its adhesive properties and fall off. At the same time, the skin will feel uncomfortable due to long-term contact with water, and even allergic rashes will occur.

[0005] Therefore, providing a technical means to improve the non-water absorption of acrylic adhesives while maintaining their excellent adhesive properties is a technical problem that needs to be solved urgently. Summary of the invention

[0006] To achieve the above object, the present invention provides a sweat-absorbing acrylic adhesive and a preparation method thereof.

[0007] The present invention provides a sweat-absorbing acrylic adhesive, the raw materials of which include:

[0008] 60-90 parts of acrylate;

[0009] 40-60 parts of acrylate, wherein the acrylate is selected from magnesium acrylate and / or calcium acrylate;

[0010] 10-20 parts of polyvinyl alcohol, wherein the weight average molecular weight of the polyvinyl alcohol is 50000-90000;

[0011] 0.1-1.0 parts of initiator;

[0012] 50-150 parts of solvent.

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

[0014] In a preferred embodiment of the present invention, the amount of the acrylic acid ester is 70-90 parts, for example, 70 parts, 80 parts or 90 parts.

[0015] In a preferred embodiment of the present invention, the amount of the acrylate is 50-60 parts, such as 50 parts or 60 parts.

[0016] In a preferred embodiment of the present invention, the amount of polyvinyl alcohol is 15-20 parts.

[0017] In a preferred embodiment of the present invention, the weight average molecular weight of the polyvinyl alcohol is 60,000-90,000, for example, 70,000.

[0018] In a preferred embodiment of the present invention, the initiator is sodium persulfate and sodium thiosulfate. The molar ratio of the sodium persulfate to the sodium thiosulfate can be 1:1.

[0019] In a preferred embodiment of the present invention, the initiator is one or more combinations of azobisisobutyronitrile, dibenzoyl peroxide, dodecanoyl peroxide, benzoyl peroxide and azobisisoheptylnitrile.

[0020] In a preferred embodiment of the present invention, the amount of the initiator is 0.2-0.6 parts, such as 0.3 parts or 0.6 parts.

[0021] In a preferred embodiment of the present invention, the amount of the solvent is 100 parts.

[0022] In a preferred embodiment of the present invention, the solvent is glycerol or 70% by volume ethanol.

[0023] The present invention also provides a method for preparing the sweat-absorbing acrylic adhesive, comprising the following steps:

[0024] S1, sequentially adding the acrylic ester, the acrylic acid salt, the polyvinyl alcohol, and 20-60% by weight of the solvent into a reaction container 1, and stirring evenly to obtain a mixture A;

[0025] S2, heating the mixed material A to 70-80° C., then slowly dropping 20-30% by weight of the initiator into the reaction solution for 0.5-1 h, and then keeping the mixture at 70-80° C. for 1-2 h to obtain a mixed material B;

[0026] S3, 10-30% by weight of the solvent and 20-30% by weight of the initiator are stirred evenly and then slowly added dropwise to the mixture B for 2-4 hours, followed by heat preservation at 70-80° C. for 0.2-0.4 hours to obtain a mixture C;

[0027] S4, adding the remaining initiator and solvent into the mixed material C, heating to 80-90° C., and reacting for 1-3 hours; after the reaction is completed, cooling the reaction liquid to 20-30° C. to obtain the sweat-absorbing acrylic adhesive.

[0028] The reagents and raw materials used in the present invention are commercially available.

[0029] The positive and progressive effects of the present invention are:

[0030] The acrylic adhesive of the present invention has excellent water absorption and water retention properties, strong bonding force and good high temperature resistance. DETAILED DESCRIPTION

[0031] 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.

[0032] In the following examples and comparative examples, the sources of the raw materials are as follows:

[0033] PVA: polyvinyl alcohol, purchased from Shanghai Aladdin.

[0034] Magnesium acrylate: CAS registration number 5698-98-6.

[0035] Calcium acrylate: CAS registration number 51366-35-9.

[0036] Sodium acrylate: CAS registration number 7446-81-3.

[0037] Examples 1-5, Comparative Examples 1-3

[0038] The acrylic adhesives in Examples 1-5 and Comparative Examples 1-3 are formulated in parts by weight as shown in Table 1 below.

[0039] Table 1

[0040]

[0041] According to the formula shown in Table 1, the preparation method is as follows:

[0042] S1, add acrylate, acrylate, PVA and 50 parts of solvent in a 100 mL single-necked flask in sequence, stir evenly, and obtain a mixture A;

[0043] S2, heating the mixed solution A to 70°C, then slowly dropping an initiator accounting for 30% of the total weight of the initiator into the mixed solution, the dropping time is 0.5h, and the mixture is kept at 70°C for 1h to obtain a mixed material B;

[0044] S3, 30 parts of solvent and 30% of the initiator by weight of the total initiator are uniformly mixed, and slowly added dropwise to the mixture B for 2 hours, and the mixture is kept at 70° C. for 0.2 hours to obtain a mixture C;

[0045] S4, adding the remaining initiator 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 to obtain acrylic glue.

[0046] Comparative Example 1

[0047] Except that the weight average molecular weight Mw of PVA is 40,000, other conditions are the same as those in Example 1.

[0048] Comparative Example 2

[0049] Except that the weight average molecular weight Mw of PVA is 100,000, other conditions are the same as those in Example 1.

[0050] Comparative Example 3

[0051] Except that the type of acrylate is sodium acrylate, other conditions are the same as those in Example 1.

[0052] Effect Example 1

[0053] The acrylic glue in Examples 1-5 and Comparative Examples 1-3 was in gel form, and a water absorption swelling ratio experiment and a water retention test were conducted.

[0054] (1) Determination of water absorption swelling ratio

[0055] The swelling ratio is usually defined as the ratio of the volume or size of the material after absorbing water to the original state. There are various methods for testing the swelling ratio, and the common ones are water immersion method, steam adsorption method, etc. This embodiment adopts the water immersion method.

[0056] The gel was cut into 20 mm*20 mm sheet samples, dried in a vacuum drying oven to a constant weight Wd, and soaked in deionized water at room temperature. The hydrogel was taken out at regular intervals, left to stand for 5 minutes, and then the surface moisture was wiped with filter paper. The weight Wt was weighed until the swelling equilibrium was reached, and the water absorption swelling ratio SR = (Wt-Wd) / Wd*100%. The test results are shown in Table 2.

[0057] (2) Determination of water retention

[0058] The acrylic glue after water absorption and swelling equilibrium is weighed Wd, and then placed in a 65°C vacuum oven for constant temperature storage. It is taken out and weighed at regular intervals, recorded as Wt'. The water retention performance of the hydrogel is expressed by the time-varying water content, and the water content Wc = (Wd-Wt') / Wd*100%. The test results are shown in Table 3.

[0059] Table 2

[0060]

[0061]

[0062] Table 3

[0063] Effect Example 2

[0064] Take 100 parts of the acrylic glue in Example 1-5 and Comparative Example 1-3, 1.4 parts of a curing agent (isocyanate), and 34 parts of propylene glycol as a solvent; add propylene glycol to the curing agent to obtain a curing agent solution; add the curing agent solution to the acrylic glue, mix and stir evenly to obtain a mixed solution.

[0065] The mixed liquid was evenly coated on the corona surface of a 50 μm thick PET base film, and it was placed in a 90°C oven for 3 min until the adhesive surface was completely dry, and the dry adhesive thickness was controlled to be 9 μm; then, a 50 μm thick release film was covered on the adhesive surface to protect the adhesive surface, and it was placed in a 50°C oven for curing for 3 days.

[0066] Performance Test:

[0067] 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℃ 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 the oven at 180℃ for 1h and after cooling to room temperature. The results are shown in Table 4.

[0068] Table 4

[0069]

Claims

1. A sweat-absorbing acrylic adhesive, characterized in that: Its raw materials include: 60-90 parts of acrylate; 40-60 parts of acrylate, wherein the acrylate is selected from magnesium acrylate and / or calcium acrylate; 10-20 parts of polyvinyl alcohol, wherein the weight average molecular weight of the polyvinyl alcohol is 50000-90000; 0.1-1.0 parts of initiator; 50-150 parts of solvent.

2. The sweat-absorbing acrylic adhesive according to claim 1, characterized in that: The type of the acrylic acid ester is methyl acrylate, ethyl acrylate, isobutyl acrylate, isooctyl acrylate or n-butyl acrylate; And / or, the amount of the acrylic acid ester is 70-90 parts.

3. The sweat-absorbing acrylic adhesive according to claim 1, characterized in that: The amount of the acrylic acid ester is 70 parts, 80 parts or 90 parts.

4. The sweat-absorbing acrylic adhesive according to claim 1, characterized in that: The amount of the acrylate is 50-60 parts; And / or, the amount of polyvinyl alcohol is 15-20 parts.

5. The sweat-absorbing acrylic adhesive according to claim 1, characterized in that: The weight average molecular weight of the polyvinyl alcohol is 60,000-90,000.

6. The sweat-absorbing acrylic adhesive according to claim 1, characterized in that: The weight average molecular weight of the polyvinyl alcohol is 70,000.

7. The sweat-absorbing acrylic adhesive according to claim 1, characterized in that: The initiators are sodium persulfate and sodium thiosulfate, and the molar ratio of the sodium persulfate to the sodium thiosulfate is 1:

1.

8. The sweat-absorbing 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 amount of the initiator is 0.2-0.6 parts.

9. The sweat-absorbing acrylic adhesive according to claim 1, characterized in that: The initiator is present in an amount of 0.3 or 0.6 parts; And / or, the number of parts of the solvent is 100 parts; And / or, the solvent is glycerol or 70% by volume ethanol.

10. A method for preparing the sweat-absorbing acrylic adhesive according to any one of claims 1 to 9, characterized in that: The steps include: S1, sequentially adding the acrylic ester, the acrylic acid salt, the polyvinyl alcohol, and 20-60% by weight of the solvent into a reaction container 1, and stirring evenly to obtain a mixture A; S2, heating the mixed material A to 70-80° C., then slowly dropping 20-30% by weight of the initiator into the reaction solution for 0.5-1 h, and then keeping the mixture at 70-80° C. for 1-2 h to obtain a mixed material B; S3, 10-30% by weight of the solvent and 20-30% by weight of the initiator are stirred evenly and then slowly added dropwise to the mixture B for 2-4 hours, followed by heat preservation at 70-80° C. for 0.2-0.4 hours to obtain a mixture C; S4, adding the remaining initiator and solvent into the mixed material C, heating to 80-90° C., and reacting for 1-3 hours; after the reaction is completed, cooling the reaction liquid to 20-30° C. to obtain the sweat-absorbing acrylic adhesive.

Images