A solvent-based self-crosslinking acrylate resin and preparation method thereof

Abstract

The present invention discloses a solvent-based self-crosslinking acrylate resin and a preparation method thereof. The raw materials include the following components by weight: 80-105 parts of a vinyl monomer, 49-85 parts of a soft monomer, 20-60 parts of a hard monomer, 2-6 parts of a functional monomer, 1-2 parts of an initiator, 1-9 parts of an organic amine, and 200-220 parts of a solvent. The functional monomer is diacetone acrylamide, and the organic amine is a linear diamine (such as decanediamine) with 10 or more carbon atoms or a modified organic amine obtained by a Michael addition reaction between a difunctional acrylate monomer and aqueous ammonia. The present invention utilizes the properties of diacetone acrylamide reacting with specific amine compounds to achieve single-component self-crosslinking in a solvent-based acrylate resin, thereby preparing an acrylate resin that is easy to store for a long time without deterioration, easy to operate during use, and has both flexibility and high-temperature resistance.

Description

Technical Field

[0001] The present invention relates to a self-crosslinking acrylate resin and a preparation method thereof, in particular to a solvent-based self-crosslinking modified acrylate resin and a preparation method thereof. Background Art

[0002] Two-component acrylic resins are composed of two chemical substances: one is a polyurethane or epoxy resin, and the other is an acrylate. When these two substances are mixed, a chemical reaction occurs, resulting in a product with excellent properties, such as high mechanical strength, water resistance, and oil resistance. However, the two-component cross-linking system consists of two components: a base resin and a curing agent. These components must be stored separately and mixed in a specific ratio for use. Because it is a two-component resin, the correct mixing ratio and method of use must be mastered during mixing, and thorough stirring is required to prevent unsatisfactory curing due to uneven mixing. The remaining material after mixing cannot be stored or reused due to its easy cross-linking, and must be scrapped, resulting in waste and, if improperly handled, environmental pollution. When using a polyurethane curing agent, it is important to consider the chemical reactions that occur with long-term exposure to air. When using an epoxy curing agent, the cured product may suffer from changes in appearance due to oxidation of the epoxy resin. Compared with the two-component system, the one-component self-crosslinking acrylic resin has the following advantages on the basis of meeting the performance requirements: good storage stability, low construction difficulty, easy operation, beautiful finished product, and reduced material waste caused by resin crosslinking or uneven mixing.

[0003] Patents CN104804126A and CN108794682A disclose the synthesis of a self-crosslinking waterborne acrylic resin by introducing a ketone hydrazine structure (crosslinking reaction of diacetone acrylamide and adipic acid dihydrazide) into an acrylic resin emulsion, thereby preparing a one-component acrylic resin. However, this method is only feasible for waterborne acrylic resins; currently, one-component self-crosslinking cannot be achieved with solvent-based acrylic resins. Summary of the Invention

[0004] Purpose of the invention: The present invention aims to provide a one-component solvent-based self-crosslinking acrylate resin having both flexibility and high temperature resistance; another object of the present invention is to provide a method for preparing the solvent-based self-crosslinking acrylate resin.

[0005] Technical solution: The solvent-based self-crosslinking acrylate resin of the present invention comprises the following components in parts by weight:

[0006]

[0007]

[0008] The functional monomer is diacetone acrylamide, and the organic amine is a linear diamine or a modified organic amine having a carbon number of ≥10. The modified organic amine is obtained by Michael addition reaction of a difunctional acrylate monomer and ammonia water.

[0009] Preferably, the vinyl monomer is vinyl acetate.

[0010] Preferably, the soft monomer is an alkyl acrylate, specifically one or more of n-butyl acrylate, isobutyl acrylate, octyl methacrylate, ethyl acrylate, methyl acrylate, octyl acrylate, isooctyl acrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, and hydroxyethyl acrylate; the hard monomer is an alkyl acrylate, specifically one or more of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, isobornyl methacrylate, and isobornyl acrylate.

[0011] Preferably, the initiator is one of azo initiators such as azobisisobutyronitrile (AIBN), azobisisovaleronitrile (AMBN), azobisisoheptanenitrile (ABVN), dimethyl azobisisobutyrate (AIBME), azoisobutylcyanamide (CABN), and azobiscyclohexylcarbonitrile (ACCN). The azo initiator has an operating temperature range of above 50°C, decomposes evenly, forms only one free radical, has no other side reactions, is relatively stable, can be safely stored in its pure state, has easy-to-control polymerization reactions, has no residue during the polymerization process, and has a high product conversion rate.

[0012] Preferably, the solvent is an alcohol or ester solvent, the alcohol solvent is one or more of ethanol and isopropanol, and the ester solvent is one or more of ethyl acetate, n-propyl acetate, and butyl acetate.

[0013] Preferably, the modified organic amine is

[0014] Preferably, the organic amine is decanediamine.

[0015] The preparation method of the solvent-based self-crosslinking acrylate resin comprises the following steps:

[0016] (1) adding part of component 1 and part of the solvent into a reaction kettle, mixing evenly, and heating to reflux;

[0017] (2) adding the remaining component 1, components 2-5 and part of the solvent into the reaction kettle;

[0018] (3) After the addition is completed, the reaction temperature is kept at reflux and the reaction is continued;

[0019] (4) After the reaction is complete, add some solvent, stir evenly, and cool;

[0020] (5) Add the mixed solution of component 6 and the remaining solvent to the prepared acrylic resin, and mix them evenly to obtain the solvent-based self-crosslinking acrylic resin.

[0021] Preferably, the amount of solvent added in steps (1) and (2) is 22-24% of the total mass of the solvent, the amount of solvent added in step (4) is 44-49% of the total mass of the solvent, and the amount of solvent added in step (5) is 1-10% of the total mass of the solvent; the amount of component 1 added in steps (1) and (2) is 47-63% and 37-53% of the total mass of component 1, respectively.

[0022] Preferably, the dropwise addition time in step (2) is 3-5 hours, and the reaction time in step (3) is 3-5 hours.

[0023] Preferably, the synthesis method of the modified organic amine comprises the following steps:

[0024] Add ammonia water and ethanol solvent to the reactor, stir, cool to 5-10°C, gradually add ethanol solution of difunctional acrylate monomer, react at 5-10°C for 4-6 hours, return to room temperature and continue the reaction, and finally obtain ethanol solution of modified organic amine for use.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The resin is a one-component self-crosslinking resin, which solves the problems of two-component acrylic resins being difficult to store, having high construction requirements, being difficult, and wasting materials, and realizes one-component self-crosslinking in solvent-based acrylic resins; (2) By utilizing the reaction characteristics of diacetone acrylamide and specific amine compounds, one-component self-crosslinking is realized in solvent-based acrylic resins, thereby preparing an acrylic resin that is easy to store for a long time without deterioration, is easy to operate during use, and has both flexibility and high temperature resistance. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0027] The preparation process of modified organic amine is as follows:

[0028] Weigh 2 mol of aqueous ammonia and ethanol solvent into a reactor, stir, and cool to 5-10°C. Gradually add 1.1 mol of an ethanol solution of a difunctional acrylate monomer (ethylene glycol diacrylate or 1,4-butanediol dimethacrylate, etc.) dropwise. React at 5-10°C for 4-6 hours. Return to room temperature and continue the reaction for 3 hours to obtain an ethanol solution of the target modified organic amine (organic amine content 40%), which is set aside.

[0029] The synthetic route of modified organic amine 1 is as follows:

[0030]

[0031] The synthetic route of modified organic amine 2 is as follows:

[0032]

[0033] Example 1

[0034] 50 g of vinyl acetate and 50 g of ethanol were added to a reactor, mixed evenly, and heated to reflux; a solution obtained by mixing 40 g of vinyl acetate, 40 g of butyl methacrylate, 45 g of hydroxyethyl acrylate, 15 g of methyl methacrylate, 8 g of isobornyl acrylate, 2 g of diacetone acrylamide, 1 g of azobisisobutyronitrile, and 50 g of ethanol was added dropwise to the reactor for 3 hours; after the addition was completed, the reaction temperature was maintained at reflux, and the reaction was continued for 5 hours; after the reaction was completed, 100 g of ethanol was added, stirred evenly, and cooled to below 50° C.; 1.0 g of decanediamine and 9 g of ethanol were mixed evenly, added to the prepared acrylic resin, stirred evenly, and discharged to obtain the target resin solution.

[0035] Examples 2-8 and Comparative Examples 1-4 were carried out with reference to the method of Example 1, and the specific parameters are shown in Tables 1 and 2.

[0036] Table 1

[0037]

[0038]

[0039] Table 2

[0040]

[0041]

[0042] The obtained target resin solution was subjected to performance tests:

[0043] 1. Flexibility test

[0044] The specific method is as follows:

[0045] 1) The resin solutions of Examples 1-8 and Comparative Examples 1-4 were adjusted to the same solid content (20-30%) using ethanol or ethyl acetate solvent.

[0046] 2) Using a printing proofing machine, print the resin solution with adjusted solid content on a PET film to produce resin coating samples with the same wet film thickness.

[0047] 3) Dry at 120°C for 2 hours to ensure that the solvent in the resin solution is completely evaporated.

[0048] 4) Fold the dried resin coating sample in half with the coated surface facing the coated surface. At room temperature, use a 2 kg roller to roll back and forth along the fold 10 times (one back and forth counts as one time).

[0049] 5) Open the sample and observe whether there are any cracks in the resin coating at the fold. The test results are shown in Table 3.

[0050] 6) Judgment standard: cracks are unqualified; no cracks are qualified.

[0051] 2. Temperature resistance test

[0052] Test principle:

[0053] Use a heat sealer with temperature display and control to test the maximum temperature that the resin coating sample can withstand to determine the temperature resistance of the resin.

[0054] The specific method is as follows:

[0055] 1) The resin solutions of Examples 1-8 and Comparative Examples 1-4 were adjusted to the same solid content (20-30%) using ethanol or ethyl acetate solvent.

[0056] 2) Using a printing proofing machine, print the resin solution with adjusted solid content on a PET film to produce resin coating samples with the same wet film thickness.

[0057] 3) Dry at 120°C for 2 hours to ensure that the solvent in the resin solution is completely evaporated.

[0058] 4) Place A4 paper on the coated surface of the dried resin coating sample.

[0059] 5) Set the heat sealer temperature, pressure to 0.3 MPa, and time to 1 second

[0060] 6) Place the sample on the heat sealer with the PET side facing up, touching the upper end of the clamp (high temperature heating), and the A4 paper facing down, touching the lower end of the clamp. Press the test button to start the test, and remove the sample after the clamp is released.

[0061] 7) Peel off the A4 paper and observe whether the resin coating on the PET film is transferred to the A4 paper.

[0062] 8) The temperature resistance of the sample was determined by the highest temperature at which the resin coating did not transfer to the A4 paper. The test results are shown in Table 3.

[0063] 9) Judgment standard: below 140℃ is unqualified; 140-149℃ is qualified; 150-154℃ is good; 155℃ and above is excellent.

[0064] Table 3 Test results of Examples 1-8 and Comparative Examples 1-4

[0065] name Whether there are cracks Maximum temperature resistance (℃) Comprehensive judgment Example 1 none 150 good Example 2 none 145 qualified Example 3 none 160 Excellent Example 4 none 140 qualified Example 5 none 150 good Example 6 none 155 Excellent Example 7 none 140 qualified Example 8 none 160 Excellent Comparative Example 1 have 125 Unqualified Comparative Example 2 have 160 Unqualified Comparative Example 3 none 110 Unqualified Comparative Example 4 none 100 Unqualified

[0066] It can be seen from the data in Table 3 that the self-crosslinking acrylate resin prepared in the present invention has no cracks and a temperature resistance greater than 140° C., meeting the performance requirements.

[0067] As shown in Table 3, Examples 1 through 8 employ long-chain organic amines (decanediamine, and homemade modified organic amines 1 and 2) to prepare solvent-based self-crosslinking acrylates that meet both flexibility and high-temperature resistance requirements. Comparative Examples 1, 3, and 4 employ short-chain diamines, but the resulting resins fail to meet the required flexibility and temperature resistance. Comparative Example 2, which does not employ crosslinking but simply increases the resin's hardness to improve temperature resistance, results in a brittle, inflexible resin coating.

Claims

1. A solvent-based self-crosslinking acrylate resin, characterized in that: Its raw materials include the following components in parts by weight: Component 1: 80-105 parts of vinyl acetate Component 2: 49-85 parts of soft monomer Component 3: 20-60 parts of hard monomer Component 4: 2-6 parts of functional monomer Component 5: 1-2 parts initiator Component 6: 1-9 parts of organic amine Component 7: 200-220 parts solvent The functional monomer is diacetone acrylamide, and the organic amine is a linear diamine or a modified organic amine having a carbon number of ≥10. The modified organic amine is obtained by Michael addition reaction of a difunctional acrylate monomer and ammonia water.

2. The solvent-based self-crosslinking acrylate resin according to claim 1, characterized in that The soft monomer is one or more of n-butyl acrylate, isobutyl acrylate, octyl methacrylate, ethyl acrylate, methyl acrylate, octyl acrylate, isooctyl acrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, and hydroxyethyl acrylate.

3. The solvent-based self-crosslinking acrylate resin according to claim 1, characterized in that The hard monomer is one or more of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, isobornyl methacrylate, and isobornyl acrylate.

4. The solvent-based self-crosslinking acrylate resin according to claim 1, characterized in that The initiator is an azo initiator.

5. The solvent-based self-crosslinking acrylate resin according to claim 1, characterized in that: The solvent is an alcohol or ester solvent.

6. A method for preparing the solvent-based self-crosslinking acrylate resin according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Add part of component 1 and part of the solvent into a reactor, mix well, and heat to reflux; (2) Add the remaining component 1 and components 2-5 and a portion of the solvent into the reaction kettle; (3) After the addition is completed, the reaction temperature is kept at reflux and the reaction continues; (4) After the reaction is completed, add some solvent, stir evenly, and cool; (5) Add the mixed solution of component 6 and the remaining solvent to the prepared acrylic resin, and mix them evenly to obtain the solvent-based self-crosslinking acrylic resin.

7. The method for preparing the solvent-based self-crosslinking acrylate resin according to claim 6, wherein: The amount of solvent added in steps (1) and (2) is 22-24% of the total mass of the solvent, the amount of solvent added in step (4) is 44-49% of the total mass of the solvent, and the amount of solvent added in step (5) is 1-10% of the total mass of the solvent; the amount of component 1 added in steps (1) and (2) is 47-63% and 37-53% of the total mass of component 1, respectively.

8. The method for preparing the solvent-based self-crosslinking acrylate resin according to claim 6, wherein: The dropwise addition time in step (2) is 3-5 hours, and the reaction time in step (3) is 3-5 hours.

9. The method for preparing the solvent-based self-crosslinking acrylate resin according to claim 6, wherein: The synthesis method of the modified organic amine comprises the following steps: adding ammonia water and ethanol solvent to a reactor, stirring, cooling to 5-10° C., gradually adding dropwise an ethanol solution of a bifunctional acrylate monomer, reacting at 5-10° C. for 4-6 hours, returning to room temperature and continuing the reaction, and finally obtaining an ethanol solution of the modified organic amine for standby use.

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