阅读说明：本技术 压敏胶、压敏胶层、制备压敏胶的方法和制备压敏胶层的方法 (Pressure-sensitive adhesive, pressure-sensitive adhesive layer, method for preparing pressure-sensitive adhesive and method for preparing pressure-sensitive adhesive layer ) 是由 宁雪峰 郑宏恩 于 2021-08-30 设计创作，主要内容包括：本发明涉及一种压敏胶,该压敏胶包括丙烯酸及其衍生物、多元醇及其衍生物、环氧树脂衍生物、硅烷偶联剂、引发剂、润湿剂、消泡剂、去离子水。本发明还涉及一种压敏胶层,压敏胶层包含压敏胶的固化反应产物。本发明还涉及一种制备压敏胶的方法和一种制备压敏胶层的方法。(The invention relates to a pressure-sensitive adhesive which comprises acrylic acid and derivatives thereof, polyhydric alcohol and derivatives thereof, epoxy resin derivatives, silane coupling agent, initiator, wetting agent, defoaming agent and deionized water. The present invention also relates to a pressure-sensitive adhesive layer comprising a cured reaction product of a pressure-sensitive adhesive. The invention also relates to a method for preparing the pressure-sensitive adhesive and a method for preparing the pressure-sensitive adhesive layer.)

1. The pressure-sensitive adhesive is characterized by comprising acrylic acid and derivatives thereof, polyhydric alcohol and derivatives thereof, epoxy resin derivatives, silane coupling agents, initiators, wetting agents, defoaming agents and deionized water.

2. The adhesive of claim 1 wherein the acrylic acid and its derivatives are a combination of ethyl acrylate, chloroethyl acrylate, acrylic acid, methyl acrylate, ethyl acrylate, vinyl acrylate.

3. The adhesive of claim 2, wherein the polyol and the derivative thereof are a combination of propanolamine, ethanol, triethanolamine, ethylene glycol, polyvinyl alcohol, propanolamine, isopropanol, n-propanol, panthenol.

4. The adhesive of claim 3, wherein the epoxy resin derivative is a combination of bisphenol A epoxy resin and novolac epoxy resin.

5. The adhesive according to claim 4, wherein the silane coupling agent is polydimethylsiloxane.

6. The adhesive of claim 5 wherein the initiator is a combination of di-t-butyl peroxide and 2, 4-dichloroperoxybenzoyl.

7. A pressure-sensitive adhesive layer comprising a cured reaction product of the pressure-sensitive adhesive according to claim 6.

8. A method of making a pressure sensitive adhesive, the method comprising the steps of: mixing the components of the pressure sensitive adhesive of claim 6.

9. A method of making a pressure sensitive adhesive layer, the method comprising the steps of: curing the pressure sensitive adhesive according to claim 6 at an ambient temperature of 75-90 ℃.

Technical Field

The invention relates to the field of adhesives, in particular to a pressure-sensitive adhesive, a pressure-sensitive adhesive layer, a method for preparing the pressure-sensitive adhesive and a method for preparing the pressure-sensitive adhesive layer.

Background

The pressure sensitive adhesive is a pressure sensitive adhesive. When in use, the pressure-sensitive adhesive can be firmly adhered to an adherend by applying only slight finger pressure without the aid of a solvent, heat or other means. The most widely used pressure sensitive adhesive at present is acrylate pressure sensitive adhesive.

However, the pressure-sensitive adhesive is oily pressure-sensitive adhesive at present, and the invention aims to provide a water-based pressure-sensitive adhesive composition.

Disclosure of Invention

The invention aims to provide a water-based pressure-sensitive adhesive, and a pressure-sensitive adhesive layer prepared from the water-based pressure-sensitive adhesive has almost no difference in various performance parameters compared with a pressure-sensitive adhesive layer prepared from an oily pressure-sensitive adhesive.

The first aspect of the present invention provides a pressure-sensitive adhesive, which is an aqueous system, and the solvent of the pressure-sensitive adhesive comprises: deionized water and a co-solvent having hydrophilic functional groups.

The pressure-sensitive adhesive comprises:

acrylic acid and derivatives thereof;

polyols and derivatives thereof;

an epoxy resin derivative;

a silane coupling agent;

an initiator;

a wetting agent;

defoaming agents;

deionized water.

Wherein, the mass of the acrylic acid and the derivatives thereof accounts for 34 to 57 percent of the total mass of the pressure sensitive adhesive, and the mass of the polyhydric alcohol and the derivatives thereof accounts for 6.5 to 10 percent of the total mass of the pressure sensitive adhesive.

A second aspect of the present invention provides a pressure-sensitive adhesive layer comprising a cured reaction product of the pressure-sensitive adhesive provided by the first aspect of the present invention.

A third aspect of the present invention provides a method of preparing a pressure-sensitive adhesive, the method comprising the steps of: the components of the pressure sensitive adhesive provided according to the first aspect of the invention are mixed for polymerization.

A fourth aspect of the present invention provides a method of preparing a pressure sensitive adhesive layer, the method comprising the steps of: the pressure-sensitive adhesive layer is prepared by adjusting the pressure-sensitive adhesive to a solid content (25-50%) suitable for coating using deionized water to prepare a slurry, and then coating the slurry on a support, wherein the pressure-sensitive adhesive layer is formed after the slurry is cured.

The pressure-sensitive adhesive layer prepared by the water-based pressure-sensitive adhesive provided by the invention can realize low adhesive force during initial pasting, can realize rework, and then ensures that the pressure-sensitive adhesive layer does not fall off along with the increase of the adhesive force along with the extension of the pasting time, and has good shear drop resistance.

The pressure-sensitive adhesive layer prepared by the water-based pressure-sensitive adhesive provided by the invention has good bonding force to a surface material, and greatly enhances the cohesive strength to achieve the effect of no adhesive residue and removal.

The pressure-sensitive adhesive layer provided by the invention can be suitable for various purposes which are applicable to the pressure-sensitive adhesive layer prepared by using the oily pressure-sensitive adhesive in the past. The pressure-sensitive adhesive layer provided by the present invention is useful as, for example, a pressure-sensitive adhesive tape for electrical insulation, and can be used as a pressure-sensitive adhesive tape for insulation, a pressure-sensitive adhesive tape for indication, a pressure-sensitive adhesive tape for identification, and the like, which are used for the protection or bundling of a wire harness of an automobile, the interlayer insulation and the outer surface insulation of electrical parts, electronic parts, and the like of a transformer, a coil, and the like. The pressure-sensitive adhesive layer provided by the invention is suitable for pressure-sensitive adhesive tapes for various purposes such as pressure-sensitive adhesive tapes for packaging corrugated boards, pressure-sensitive adhesive tapes for medical treatment, pressure-sensitive adhesive tapes for shielding and the like.

The following description will be given with reference to specific examples.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a pressure-sensitive adhesive, which is an aqueous system and comprises the following components: acrylic acid and derivatives thereof, polyhydric alcohol and derivatives thereof, epoxy resin derivatives, silane coupling agents, initiators, wetting agents, defoaming agents and deionized water.

The pressure-sensitive adhesive can be obtained by mixing the components of the pressure-sensitive adhesive provided by the invention. Preferably, the components of the pressure-sensitive adhesive provided by the invention are mixed in a glass container or a reaction kettle at the temperature of 20-30 ℃ and under the pressure of 1 atmosphere to obtain the pressure-sensitive adhesive.

The slurry prepared by mixing the pressure-sensitive adhesive and the deionized water can be coated on a proper carrier, and then the coated slurry is cured at high temperature to form the pressure-sensitive adhesive layer. The carrier may be rigid, flexible, transparent, or opaque, and may be made of any suitable material, such as a polymeric material, a glass or ceramic material, a metal, and the like. In some preferred embodiments, the carrier may be a polymeric material, for example a flexible polymeric film which may be a flexible backing. Suitable polymeric materials may include: polyolefin, polystyrene, polyester, nylon, polyvinyl alcohol, poly (vinylidene fluoride), or cellulose (e.g., cellulose acetate, or ethyl cellulose). The flexible support may have a specific microstructured surface. The support may also be made from a fabric, such as a fabric formed from synthetic or natural fibers. The fabric may be woven or non-woven. The suitable fibers may include cotton, nylon, rayon, glass, or ceramic. In addition, other suitable carriers may also include metal sheets, metal foils, metallized polymer films, ceramic sheets, or foams (such as acrylic foams, polyethylene foams, polyurethane foams, or neoprene foams).

The slurry disclosed by the invention can be adapted to a coated carrier by adjusting the leveling property and the sagging property of the slurry through adjusting the mass ratio of the pressure-sensitive adhesive to the deionized water. The slurry can be applied to the support using any suitable method, such as roll coating, flow coating, dip coating, spin coating, spray coating, knife coating, or die coating. These different coating methods allow for various suitable thicknesses of the slurry to be coated onto the support. The coating thickness may vary, wherein typical thicknesses of the pressure sensitive adhesive layer may be in the range of 2-500 μm, and may also be in the range of 25-250 μm.

The pressure-sensitive adhesive provided by the invention can be subjected to polymerization reaction in a high-temperature environment so as to be cured to form a pressure-sensitive adhesive layer, the polymerization reaction is induced to generate free radicals in the high-temperature environment through an initiator, the whole reaction temperature is controlled to be 75-90 ℃, and the curing of the pressure-sensitive adhesive in the high-temperature environment can comprise the following steps: (1) generation of free radicals: initiating agent under high temperature environment to decompose and generate free radical; (2) chain initiation: initiating unsaturated double bonds in resin and monomer molecules to generate new free radicals by the free radicals generated by the initiator; (3) chain extension: the free radicals generated by the resin and the monomer can further initiate unsaturated double bonds in the resin and the monomer molecules to generate free radicals for free radical chain reaction; and (4) chain termination: in chemical reactions, free radicals are susceptible to radical coupling or acidification due to their uncoupled electrons to terminate the chain reaction. As a result of the above reaction, the pressure-sensitive adhesive is cured to form a pressure-sensitive adhesive layer.

The specific component ratios of the pressure-sensitive adhesives provided in examples 1-5 are shown in table 1.

Pressure-sensitive adhesive layers with the same thickness were respectively prepared on the TPU adhesive films of the pressure-sensitive adhesives provided in examples 1 to 5 and the existing oily pressure-sensitive adhesives, to thereby obtain test samples, and the performance of the test samples was tested by the following method:

1. initial tack test: the adhesive surface of the pressure-sensitive adhesive layer of the test sample is attached to a glass plate, and then reworking can be realized to be qualified by tearing the adhesive surface by hands and then not remaining the adhesive;

2. and (3) weather resistance test: bonding the adhesive surface of the pressure-sensitive adhesive layer of the test sample to a glass plate with the bonding area of 10cm²Attaching the materials back and forth for three times by using a 2kg pressure roller, standing for 20 minutes, hanging 1kg in an environment with 60 ℃ and 95% relative humidity, observing the dropping condition and recording the retention time, wherein the longer the time is, the better the weather resistance is; attaching the adhesive surface of the pressure-sensitive adhesive layer of the test sample to a PC board with the attaching area of 10cm²Attaching the materials back and forth for three times by using a 2kg pressure roller, standing for 20 minutes, hanging 1kg in an environment with 80 ℃ and 95% relative humidity, observing the dropping condition and recording the retention time, wherein the longer the time is, the better the weather resistance is;

3. adhesion test: and (3) attaching the adhesive surface of the pressure-sensitive adhesive layer of the test sample to a glass plate, standing for 30 minutes and standing for 48 hours, and then respectively testing the peeling force, wherein the peeling force is high, which indicates that the pressure-sensitive adhesive layer has good adhesiveness and is not easy to fall off in the using process.

TABLE 1

The test results are shown in table 2, and it can be seen from the test results in table 2 that the initial tack of the pressure-sensitive adhesive layers prepared from the aqueous pressure-sensitive adhesives provided in examples 1 to 5 is acceptable, the reworking is easy, the weather resistance and the adhesiveness are good, and the performance of the pressure-sensitive adhesive layers prepared from the aqueous pressure-sensitive adhesives provided in examples 1 to 5 is almost the same as that of the pressure-sensitive adhesive layers prepared from the existing oily pressure-sensitive adhesives.

TABLE 2

Compared with the pressure-sensitive adhesive of an oily system, the pressure-sensitive adhesive of the existing aqueous system has the technical problems that: 1. the stability of the system at normal temperature; 2. the initial viscosity of the pressure-sensitive adhesive layer prepared by the pressure-sensitive adhesive of the water-based system through polymerization reaction is lower than that of the pressure-sensitive adhesive layer prepared by the pressure-sensitive adhesive of the oil-based system; 3. the weather resistance of the pressure-sensitive adhesive layer prepared by the pressure-sensitive adhesive of the water-based system through polymerization reaction is inferior to that of the pressure-sensitive adhesive layer prepared by the pressure-sensitive adhesive of the oil-based system.

In order to solve the technical problems, the inventor summarizes the technical core points of solving the technical problems through a large number of tests: 1. the specific component matching of the acrylic acid and the derivative thereof determines the basic stability of the pressure-sensitive adhesive of the aqueous system and the basic performance (including initial adhesiveness, weather resistance and adhesiveness) of the pressure-sensitive adhesive layer; 2. the added polyhydric alcohol and the derivative thereof need to meet the function of improving the stability of an aqueous system and also need to meet the function of participating in polymerization reaction under a high-temperature environment to improve the initial viscosity and the weather resistance of the pressure-sensitive adhesive layer.

Therefore, through a large number of experimental comparisons, the invention unexpectedly finds that when the specific components of the acrylic acid and the derivatives thereof are ethyl acrylate, chloroethyl acrylate, acrylic acid, methyl acrylate, ethyl acrylate and vinyl acrylate, the basic performance of the pressure-sensitive adhesive layer prepared by the pressure-sensitive adhesive of the water-based system is almost not different from that of the pressure-sensitive adhesive layer prepared by the pressure-sensitive adhesive of the oil-based system. The inventor conducts screening through a large number of experiments in the existing polyhydric alcohol and the derivative thereof according to the specific components of the selected acrylic acid and the derivative thereof, and the inventor surprisingly finds that when the specific components of the polyhydric alcohol and the derivative thereof are propanolamine, ethanol, triethanolamine, ethylene glycol, polyvinyl alcohol, propanolamine, isopropanol, n-propanol and panthenol, the pressure-sensitive adhesive in an aqueous system can be stably stored for a long time at normal temperature, and the initial viscosity and the weather resistance of the pressure-sensitive adhesive layer can be improved.

In the present invention, the specific components of the initiator are determined based on the specific components of acrylic acid and its derivatives.

According to the invention, the initial viscosity and weather resistance of the pressure-sensitive adhesive layer prepared from the pressure-sensitive adhesive of the aqueous system can be obviously improved by adding the epoxy resin derivative and the silane coupling agent into the pressure-sensitive adhesive of the aqueous system.

In the invention, the wetting agent and the defoaming agent are added into the pressure-sensitive adhesive of the aqueous system, so that the storage stability of the pressure-sensitive adhesive of the aqueous system at normal temperature can be obviously improved.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.