Acrylic resin and preparation method thereof

Abstract

The invention discloses acrylic resin and a preparation method thereof, and relates to the field of acrylic resin, and the acrylic resin comprises 45-70 parts of a monomer, 5-20 parts of allyl benzyl ether, 1-3 parts of an initiator and 1-2 parts of a chain transfer agent. The acrylic resin with narrow molecular weight distribution is prepared by selecting monomer types and combining with the allyl benzyl ether and the compounded chain transfer agent as raw materials, and the water resistance and weather resistance of the thermal insulation coating prepared from the acrylic resin are improved.

Description

Technical Field

[0001] The present application relates to the field of acrylic resins, and in particular to an acrylic resin and a preparation method thereof. Background Art

[0002] Acrylic resin is a general term for polymers of acrylic acid, methacrylic acid and their derivatives. It is widely used in many industries such as machinery, electronics, construction, leather finishing, papermaking, printing and dyeing, industrial plastics and daily necessities finishing.

[0003] At present, functional monomers with functional groups are added to acrylic resins according to their different uses, so as to provide corresponding properties for the acrylic resins. For example, functional monomers containing hydroxyl groups, benzene rings and other matrices are used to improve the water resistance, weather resistance and other properties of polyacrylic resins. However, with the addition of functional monomers, the molecular weight distribution of acrylic resins will be difficult to control. If the molecular weight distribution of acrylic resins is wide, the proportion of molecular chains that do not contain functional monomers in the acrylic resin will increase, reducing the stability of the functionality of the acrylic resin, resulting in deterioration of its weather resistance, water resistance and other properties. Summary of the invention

[0004] In view of the deficiencies of the above-mentioned related technologies, the present application provides an acrylic resin and a preparation method thereof. By selecting the monomer type and combining allyl benzyl ether and a compounded chain transfer agent as raw materials, an acrylic resin with a narrow molecular weight distribution is prepared, and the water resistance and weather resistance of the acrylic resin are improved. The acrylic resin of the present application is applied to building energy-saving materials such as thermal insulation coatings to give the coating film excellent water resistance and weather resistance.

[0005] In the first aspect, the present application provides an acrylic resin using the following technical solution:

[0006] An acrylic resin is prepared from the following components in parts by weight: 45-70 parts of a monomer, 5-20 parts of allyl benzyl ether, 1-3 parts of an initiator and 1-2 parts of a chain transfer agent.

[0007] Preferably, the weight ratio of the monomer to the allyl benzyl ether is 11:1-4.

[0008] Preferably, the weight ratio of the monomer to the allyl benzyl ether is 5.5:1.

[0009] Preferably, the monomer includes one or more of methyl methacrylate, isononyl acrylate, styrene, butyl acrylate, ethyl methacrylate, hydroxyethyl acrylate, 4-hydroxybutyl acrylate, methacrylic acid and acrylic acid.

[0010] Preferably, the monomers include hydroxyethyl acrylate and isononyl acrylate in a weight ratio of 1.2-4.5:1.

[0011] Preferably, the monomers include hydroxyethyl acrylate and isononyl acrylate in a weight ratio of 1.75:1.

[0012] By adopting the above scheme, when the weight ratio of the monomer to the allyl benzyl ether is 5.5:1; and the monomers are selected to copolymerize hydroxyethyl acrylate and isononyl acrylate in a weight ratio of 1.75:1, the prepared acrylic resin has the best water resistance and weather resistance when used. This may be because, hydroxyethyl acrylate is used as a functional monomer to prepare acrylic resin to form a continuous coating film through cross-linking with a curing agent, thereby improving water resistance, aging resistance, heat resistance and other properties. However, the hydroxyl group in the acrylic resin has a certain hydrophilicity, which is not conducive to preventing water absorption. The inventor added allyl benzyl ether for copolymerization. On the one hand, the side chain introduced phenyl to improve the hydrophobicity. On the other hand, the side chain lengths of allyl benzyl ether and hydroxyethyl acrylate are close after copolymerization. The introduced phenyl forms a certain shielding for the hydroxyl group and the ester group, thereby reducing the water absorption. The steric hindrance effect of the phenyl side chain is too long and affects the cross-linking of the hydroxyl group. The phenyl side chain is too short and the shielding of the hydrophilic group is insufficient, which is not conducive to the water resistance of the subsequent coating. In addition, the hydroxyl group side chain is slightly longer than the phenyl side chain, which is conducive to cross-linking, and the participation of isononyl acrylate in the polymerization makes the molecular chain side chain have a linear hydrophobic segment. The entanglement of the hydrophobic segment in the phenyl and hydroxyl side chains further supplements the hydrophobic effect of the benzene ring shielding, and has a low effect on the participation of the hydroxyl group in the subsequent curing. Therefore, the present application selects the above three monomers to participate in the copolymerization to prepare acrylic resin, which can have both excellent water resistance and cross-linking properties, so as to obtain a coating with excellent water resistance and aging resistance when used. Furthermore, the weight ratio of the monomer to the allyl benzyl ether is 5.5:1; the weight ratio of the monomer to hydroxyethyl acrylate and isononyl acrylate is 1.75:1, so that the prepared polymer chain can effectively achieve water resistance while maintaining the optimal cross-linking effect.

[0013] Preferably, the chain transfer agent includes one or more of n-dodecyl mercaptan, tert-dodecyl mercaptan, α-methylstyrene dimer and isooctyl 3-mercaptopropionate.

[0014] Preferably, the chain transfer agent comprises tert-dodecyl mercaptan and isooctyl 3-mercaptopropionate in a weight ratio of 0.25-2:1.

[0015] Preferably, the chain transfer agent comprises tert-dodecyl mercaptan and isooctyl 3-mercaptopropionate in a weight ratio of 0.5:1.

[0016] Preferably, the ratio of the total weight of the monomer and allyl benzyl ether to the weight of the initiator is 30-37.5:1.

[0017] Preferably, the ratio of the total weight of the monomer and allyl benzyl ether to the weight of the initiator is 32.5:1.

[0018] Preferably, the initiator comprises one or more of tert-butyl peroxy-2-ethylhexanoate, azobisisobutyronitrile and azobisisovaleronitrile.

[0019] Preferably, the initiator is tert-butyl peroxy-2-ethylhexanoate.

[0020] In a second aspect, the present application provides a method for preparing an acrylic resin using the following technical solution.

[0021] A method for preparing acrylic resin comprises the following steps: mixing a monomer, allyl benzyl ether, an initiator, a chain transfer agent and a solvent for reaction at a temperature of 90-120° C. for a reaction time of 4-6 hours, and removing the solvent to obtain the acrylic resin.

[0022] Preferably, the allyl benzyl ether and the chain transfer agent are added in multiple batches during the reaction.

[0023] Preferably, 40% of allyl benzyl ether is added at the beginning of the reaction, the remaining allyl benzyl ether is added after 1.5 hours of reaction, 20% of the chain transfer agent is added after 1 hour of reaction, and the remaining chain transfer agent is added after 3 hours of reaction.

[0024] In a third aspect, the present application provides a thermal insulation coating comprising the above-mentioned acrylic resin.

[0025] In summary, the present application includes at least one of the following beneficial technical effects:

[0026] 1. By selecting the monomer types and combining allyl benzyl ether and a compounded chain transfer agent as raw materials, the hydrophobicity is improved by the phenyl group while the water absorption is reduced by the large side chain volume. On the one hand, it may be due to the selection of hydroxyethyl acrylate, isononyl acrylate and allyl benzyl ether as the main chain of the molecular chain, which increases the proportion of hydrophobic components in the main chain. At the same time, the large side chain containing hydrophobic functional groups is conducive to reducing the probability of contact between the ester group and the water molecule. The copolymerization of the three monomers improves the water resistance and crosslinking of the resin; on the other hand, by using tert-dodecyl mercaptan and isooctyl 3-mercaptopropionate as chain transfer agents, the polymer dispersibility index is reduced, so that the acrylic resin using hydroxyethyl acrylate, isononyl acrylate and allyl benzyl ether as the main chain has a narrow distribution, which improves the uniformity of the distribution of each component in the molecular chain, improves the water resistance and weather resistance, and obtains an acrylic resin with a narrow molecular weight distribution, which is conducive to forming a denser crosslinking network when crosslinked with a curing agent, thereby further improving the water resistance and weather resistance of the coating made of the thermal insulation coating;

[0027] 2. By selecting the chain transfer agent and adjusting the proportion, the molecular weight of the polyacrylic acid resin is adjusted to obtain an acrylic resin with a narrow molecular weight distribution, thereby improving the water resistance and weather resistance of the acrylic resin.

[0028] 3. By controlling the addition of allyl benzyl ether and chain transfer agent in multiple batches during the reaction process in the preparation process of acrylic resin, on the one hand, the uniformity of the distribution of allyl benzyl ether in the molecular chain is improved, and on the other hand, it is conducive to the preparation of acrylic resin with a narrow molecular weight distribution. Under the combined effect, the water resistance and weather resistance of the acrylic resin are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a molecular weight distribution diagram of the acrylic resin of Example 2 in the present application;

[0030] Figure 2 is the molecular weight distribution diagram of the acrylic resin of Example 4 in the present application;

[0031] Figure 3 is the molecular weight distribution diagram of the acrylic resin of Example 8 in the present application;

[0032] Figure 4 is a molecular weight distribution diagram of the acrylic resin of Example 9 in the present application;

[0033] Figure 5 is a molecular weight distribution diagram of the acrylic resin of Example 10 in the present application;

[0034] Figure 6 This is a molecular weight distribution diagram of the acrylic resin of Comparative Example 1;

[0035] Figure 7 This is the molecular weight distribution diagram of the acrylic resin of Comparative Example 5. DETAILED DESCRIPTION

[0036] The present application is further described in detail below in conjunction with examples. The following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. In the following examples, if specific conditions are not specified, they are carried out according to normal conditions or conditions recommended by the manufacturer. The methods used are conventional methods known in the art unless otherwise specified, and the consumables and reagents used are commercially available unless otherwise specified. Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the recorded content may also be applied to the present invention.

[0037] The raw materials used in the examples and comparative examples can all be obtained commercially.

[0038] Examples 1-7

[0039] Examples 1-7 of the present application provide an acrylic resin, which is prepared by the following steps: under nitrogen protection, a monomer, a tert-butyl peroxide-2-ethylhexanoate initiator, and allyl benzyl ether are added to a sufficient amount of butyl glycol acetate solvent, stirred and dissolved evenly, and then added to a reaction kettle, heated to 100° C., continuously stirred, and kept warm for reaction for 2 hours, a chain transfer agent is added, the reaction is continued for 3 hours, and the butyl glycol acetate solvent is removed to obtain an acrylic resin.

[0040] The chain transfer agent in Example 1-7 is prepared by uniformly mixing tert-dodecyl mercaptan and isooctyl 3-mercaptopropionate. The composition ratio of each raw material in Example 1-7 is shown in Table 1 below.

[0041] Table 1: Raw material composition and proportion of acrylic resin of Examples 1-7

[0042]

[0043] Example 8

[0044] Example 8 of the present application provides an acrylic resin. The difference between Example 8 and Example 2 is that Example 8 uses 4-hydroxybutyl acrylate to replace hydroxyethyl acrylate.

[0045] Example 9

[0046] Example 9 of the present application provides an acrylic resin. The difference between Example 9 and Example 2 is that Example 9 uses methyl acrylate to replace isononyl acrylate.

[0047] Example 10

[0048] Example 10 of the present application provides an acrylic resin. The raw material composition and ratio of Example 10 are consistent with those of Example 2, and the acrylic resin is prepared by the following steps: under nitrogen protection, a monomer, a tert-butyl peroxide-2-ethylhexanoate initiator, and 40% of allyl benzyl ether are added to a sufficient amount of ethylene glycol butyl ether acetate solvent, stirred and dissolved evenly, and then added to a reactor, heated to 100° C., continuously stirred, and kept warm for reaction for 1 hour, 20% of a chain transfer agent is added, the reaction is continued for 0.5 hour, the remaining allyl benzyl ether is added, the reaction is continued for 1.5 hours, the remaining chain transfer agent is added, the reaction is continued for 2 hours, and the ethylene glycol butyl ether acetate solvent is removed to obtain an acrylic resin.

[0049] Comparative Examples 1-5

[0050] Comparative Examples 1-5 provide an acrylic resin. The difference between Comparative Examples 1-5 and Example 2 is that the raw material compositions and proportions of Comparative Examples 1-5 are shown in Table 2 below.

[0051] Table 2: Raw material composition and proportion of acrylic resin of Comparative Examples 1-5

[0052]

[0053] Test and Inspection

[0054] (1) The molecular weight distribution of the acrylic resins of Examples 1-10 and Comparative Examples 1-5 was detected, and the polymer dispersibility index (PDI) was calculated as shown in Table 3. The molecular weight distribution diagrams of Example 2, Example 4, Examples 8-10, Comparative Example 1 and Comparative Example 5 are shown in Table 3. Figure 1-7 shown.

[0055] Table 3:

[0056]

[0057]

[0058] (2) The acrylic resins of Examples 1-10 and Comparative Examples 1-5 were respectively used to prepare thermal insulation coatings (30 parts of acrylic resin, 3 parts of isocyanate curing agent, 15 parts of thermal insulation filler, and 20 parts of solvent) under the same conditions. Water resistance tests were performed according to standard GB / T1733, and the time when abnormalities occurred was observed and recorded every 12 hours. Ageing resistance tests were performed according to standard GB / T1865, and the time when abnormalities occurred was observed and recorded every 12 hours, as shown in Table 4 below.

[0059] Table 4:

[0060]

[0061]

[0062] Results Analysis

[0063] The following combines Table 1-4 and Figure 1-7 The experimental results provided are used to explain this application in detail.

[0064] Refer to Table 3 and Table 4 and Figure 1-5 The polymer dispersibility index of the acrylic resins of Examples 1-10 is less than 2.1, and after being made into thermal insulation coatings, the water resistance is tested to be more than 200 hours, and the aging resistance is tested to be more than 140 hours, indicating that the polypropylene resins prepared by the composition ratios of Examples 1-10 of the present application have a narrow molecular weight distribution, good water resistance and weather resistance.

[0065] Taking Example 2 as a control, Examples 4-5 show the effect of the proportion of chain transfer agent used in the preparation of acrylic resin on the molecular weight distribution of the obtained acrylic resin and the corresponding water resistance and weather resistance of the thermal insulation coating. The polymer dispersibility index of the acrylic resin of Example 2 is 1.529, which is less than the polymer dispersibility index of the acrylic resin of Example 4-5, and the water resistance and aging resistance of the thermal insulation coating made of the acrylic resin of Example 2 are better than the water resistance and aging resistance of the acrylic resin of Example 4-5. This shows that the use of a chain transfer agent of 1:2 tert-dodecyl mercaptan and isooctyl 3-mercaptopropionate is conducive to narrowing the molecular weight distribution of the acrylic resin and improving the water resistance and weather resistance of the acrylic resin.

[0066] Taking Example 2 as a control, Examples 6-7 show the effect of the ratio of allyl benzyl ether to monomer used in the preparation of acrylic resin on the molecular weight distribution of the obtained acrylic resin and the corresponding water resistance and weather resistance of the thermal insulation coating. The polymer dispersibility index of the acrylic resin of Example 2 is 1.529, which is less than the polymer dispersibility index of the acrylic resin of Examples 6-7, and the water resistance and aging resistance of the thermal insulation coating made of the acrylic resin of Example 2 are better than the water resistance and aging resistance of the acrylic resin of Examples 6-7. It shows that the use of a 5.5:1 monomer and allyl benzyl ether is conducive to narrowing the molecular weight distribution of the acrylic resin and improving the water resistance and weather resistance of the acrylic resin.

[0067] With Example 2 as a control, Examples 8-9 show the influence of the type of monomer used in the preparation of acrylic resin on the molecular weight distribution of the prepared acrylic resin and the corresponding water resistance and weather resistance of the thermal insulation coating. The polymer dispersibility index of the acrylic resin in Example 2 is 1.529, which is less than the polymer dispersibility index of the acrylic resin in Examples 8-9, and the water resistance and aging resistance of the thermal insulation coating made of the acrylic resin in Example 2 are better than those of the acrylic resin in Examples 8-9, indicating that the monomer selection of hydroxyethyl acrylate and isononyl acrylate and allyl benzyl ether for copolymerization is beneficial to improving the water resistance and weather resistance of the prepared acrylic resin when used as a thermal insulation coating. This may be because, hydroxyethyl acrylate is used as a functional monomer to prepare acrylic resin to form a continuous coating film through cross-linking with a curing agent, thereby improving the water resistance, aging resistance, heat resistance and other properties. However, the hydroxyl group in the acrylic resin has a certain hydrophilicity, which is not conducive to preventing water absorption. When allyl benzyl ether is added for copolymerization, on the one hand, the side chain introduces phenyl to improve the hydrophobicity. On the other hand, after copolymerization of allyl benzyl ether and hydroxyethyl acrylate, the side chain lengths are close, and the introduced phenyl forms a certain shielding for the hydroxyl group and the ester group, thereby reducing the water absorption. If the phenyl side chain is too long, the steric hindrance effect affects the cross-linking of the hydroxyl group, and if the phenyl side chain is too short, the shielding of the hydrophilic group is insufficient, both of which are not conducive to the water resistance of the subsequent coating. In addition, the hydroxyl group side chain is slightly longer than the phenyl side chain, which is conducive to cross-linking, and the participation of isononyl acrylate in the polymerization makes the molecular chain side chain have a linear hydrophobic segment. The entanglement of the hydrophobic segment in the phenyl and hydroxyl side chains further supplements the hydrophobic effect of the benzene ring shielding, and reduces the influence of the hydroxyl participation on the subsequent curing.

[0068] With Example 2 as a control, Example 10 shows the effect of adding chain transfer agent and allyl benzyl ether in batches when preparing acrylic resin on the molecular weight distribution of the prepared acrylic resin and the water resistance and weather resistance of the corresponding thermal insulation coating. The polymer dispersibility index of the acrylic resin of Example 8 is 1.418, which is less than the polymer dispersibility index of the acrylic resin of Example 2, and the water resistance of the thermal insulation coating made of the acrylic resin of Example 8 is slightly better than the water resistance of the thermal insulation coating made of the acrylic resin of Example 2. It is analyzed that adding chain transfer agent and allyl benzyl ether in batches is beneficial to controlling the molecular weight distribution of acrylic resin while improving the uniformity of the molecular chain distribution of each component.

[0069] Refer to Table 3, Table 4 and Figure 6-7, with Example 2 as the control, the polymer dispersibility index of the acrylic resins of Comparative Examples 1-5 is much greater than that of the acrylic resin of Example 2, reaching more than 3, and the water resistance and aging resistance of the acrylic resin of Example 2 are much better than those of the acrylic resins of Comparative Examples 1-5. In Comparative Example 1, allyl benzyl ether is not added as the main chain component, and the composition and ratio of the chain transfer agent are adjusted in Comparative Examples 2-4, indicating that allyl benzyl ether is indispensable, and the use of 1:2 tert-dodecyl mercaptan and 3-isooctyl mercaptopropionate as chain transfer agents has a synergistic effect in narrowing the molecular weight distribution of the acrylic resin and improving the water resistance and weather resistance of the thermal insulation coating made of the acrylic resin.

[0070] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An acrylic resin, characterized in that: The invention is prepared from the following components in parts by weight: 45-70 parts of monomer, 5-20 parts of allyl benzyl ether, 1-3 parts of initiator and 1-2 parts of chain transfer agent.

2. An acrylic resin according to claim 1, characterized in that: The weight ratio of the monomer to the allyl benzyl ether is 11:1-4.

3. An acrylic resin according to claim 1, characterized in that: The monomers include one or more of methyl methacrylate, isononyl acrylate, styrene, butyl acrylate, ethyl methacrylate, hydroxyethyl acrylate, 4-hydroxybutyl acrylate, methacrylic acid and acrylic acid.

4. An acrylic resin according to claim 3, characterized in that: The monomers include hydroxyethyl acrylate and isononyl acrylate in a weight ratio of 1.2-4.5:

1.

5. An acrylic resin according to claim 1, characterized in that: The chain transfer agent includes one or more of n-dodecyl mercaptan, tert-dodecyl mercaptan, a-methylstyrene dimer and isooctyl 3-mercaptopropionate.

6. An acrylic resin according to claim 5, characterized in that: The chain transfer agent comprises tert-dodecyl mercaptan and isooctyl 3-mercaptopropionate in a weight ratio of 0.25-2:

1.

7. An acrylic resin according to claim 1, characterized in that: The ratio of the total weight of the monomer and allyl benzyl ether to the weight of the initiator is 30-37.5:

1.

8. An acrylic resin according to claim 1, characterized in that: The initiator includes one or more of tert-butyl peroxy-2-ethylhexanoate, azobisisobutyronitrile and azobisisovaleronitrile.

9. A method for preparing an acrylic resin as claimed in any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing monomers, allyl benzyl ether, an initiator, a chain transfer agent and a solvent for reaction at a temperature of 90-120° C. for a reaction time of 4-6 hours, and removing the solvent to obtain the acrylic resin.

10. The method for preparing an acrylic resin according to claim 9, characterized in that: The allyl benzyl ether and the chain transfer agent are added in batches during the reaction.

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